We can create a reloc root when we record the root in the trans, which
can fail for all sorts of different reasons. Propagate this error up
the chain of callers. Future patches will fix the callers of
btrfs_record_root_in_trans() to handle the error.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
record_root_in_trans can currently fail, so handle this failure
properly.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
record_root_in_trans can fail currently, handle this failure properly.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
record_root_in_trans can fail currently, so handle this failure
properly.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in start_transaction.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in relocate_tree_block.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in create_subvol.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in btrfs_recover_log_trees.
This appears tricky, however we have a reference count on the
destination root, so if this fails we need to continue on in the loop to
make sure the proper cleanup is done.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in btrfs_delete_subvolume.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in btrfs_rename.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in btrfs_rename_exchange.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Generally speaking this shouldn't ever fail, the corresponding fs root
for the reloc root will already be in memory, so we won't get ENOMEM
here.
However if there is no corresponding root for the reloc root then we
could get ENOMEM when we try to allocate it or we could get ENOENT
when we look it up and see that it doesn't exist.
Convert these BUG_ON()'s into ASSERT()'s and add proper error handling
for the case of corruption.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We will record the fs root or the reloc root in the trans in
select_reloc_root. These will actually return errors in the following
patches, so check their return value here and return it up the stack.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have several BUG_ON()'s in select_reloc_root() that can be tripped if
there is an extent tree corruption. Convert these to ASSERT()'s, because
if we hit it during testing it really is bad, or could indicate a
problem with the backref walking code.
However if users hit these problems it generally indicates corruption,
I've hit a few machines in the fleet that trip over these with clearly
corrupted extent trees, so be nice and print out an error message and
return an error instead of bringing the whole box down.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently select_reloc_root() doesn't return an error, but followup
patches will make it possible for it to return an error. We do have
proper error recovery in do_relocation however, so handle the
possibility of select_reloc_root() having an error properly instead of
BUG_ON(!root).
I've also adjusted select_reloc_root() to return ERR_PTR(-ENOENT) if we
don't find a root, instead of NULL, to make the error case easier to
deal with. I've replaced the BUG_ON(!root) with an ASSERT(0) for this
case as it indicates we messed up the backref walking code, but it could
also indicate corruption.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a couple of BUG_ON()'s in relocate_tree_block() that can be
tripped if we have file system corruption. Convert these to ASSERT()'s
so developers still get yelled at when they break the backref code, but
error out nicely for users so the whole box doesn't go down.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A few of these are checking for correctness, and won't be triggered by
corrupted file systems, so convert them to ASSERT() instead of BUG_ON()
and add a comment explaining their existence.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Implement readahead_batch_length() to determine the number of bytes in
the current batch of readahead pages and use it in btrfs. Also use the
readahead_pos to get the offset.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two forward declarations deep in extent_io.h, move them
to the beginning and remove the duplicate one.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch adds an overview how btrfs subpage support works:
- limitations
- behavior
- basic implementation points
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Current set_btree_ioerr() only accepts @page parameter and grabs extent
buffer from page::private. This works fine for sector size == PAGE_SIZE
case, but not for subpage case.
Add an extra parameter, @eb, for callers to pass extent buffer to this
function, so that subpage code can reuse this function.
And also add subpage special handling to update
btrfs_subpage::error_bitmap.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For set_extent_buffer_dirty() to support subpage sized metadata, just
call btrfs_page_set_dirty() to handle both cases.
For clear_extent_buffer_dirty(), it needs to clear the page dirty if and
only if all extent buffers in the page range are no longer dirty.
Also do the same for page error.
This is pretty different from the existing clear_extent_buffer_dirty()
routine, so add a new helper function,
clear_subpage_extent_buffer_dirty() to do this for subpage metadata.
Also since the main part of clearing page dirty code is still the same,
extract that into btree_clear_page_dirty() so that it can be utilized
for both cases.
But there is a special race between set_extent_buffer_dirty() and
clear_extent_buffer_dirty(), where we can clear the page dirty.
[POSSIBLE RACE WINDOW]
For the race window between clear_subpage_extent_buffer_dirty() and
set_extent_buffer_dirty(), due to the fact that we can't call
clear_page_dirty_for_io() under subpage spin lock, we can race like
below:
T1 (eb1 in the same page) | T2 (eb2 in the same page)
-------------------------------+------------------------------
set_extent_buffer_dirty() | clear_extent_buffer_dirty()
|- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty()
| | |- btrfs_clear_and_test_dirty()
| | | Since eb2 is the last dirty page
| | | we got:
| | | last == true;
| | |
|- btrfs_page_set_dirty() | |
| We set the page dirty and | |
| subpage dirty bitmap | |
| | |- if (last)
| | | Since we don't have subpage lock
| | | held, now @last is no longer
| | | correct
| | |- btree_clear_page_dirty()
| | Now PageDirty == false, even if
| | we have dirty_bitmap not zero.
|- ASSERT(PageDirty()); |
^^^^ CRASH
The solution here is to also lock the eb->pages[0] for subpage case of
set_extent_buffer_dirty(), to prevent racing with
clear_extent_buffer_dirty().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are quite some assert checks on page uptodate in extent buffer
write accessors. They ensure the destination page is already uptodate.
This is fine for regular sector size case, but not for subpage case, as
for subpage we only mark the page uptodate if the page contains no hole
and all its extent buffers are uptodate.
So instead of checking PageUptodate(), for subpage case we check the
uptodate bitmap of btrfs_subpage structure.
To make the check more elegant, introduce a helper,
assert_eb_page_uptodate() to do the check for both subpage and regular
sector size cases.
The following functions are involved:
- write_extent_buffer_chunk_tree_uuid()
- write_extent_buffer_fsid()
- write_extent_buffer()
- memzero_extent_buffer()
- copy_extent_buffer()
- extent_buffer_test_bit()
- extent_buffer_bitmap_set()
- extent_buffer_bitmap_clear()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In alloc_extent_buffer(), we make sure that the newly allocated page is
never dirty.
This is fine for sector size == PAGE_SIZE case, but for subpage it's
possible that one extent buffer in the page is dirty, thus the whole
page is marked dirty, and could cause false alert.
To support subpage, call btrfs_page_test_dirty() to handle both cases.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a new helper, csum_dirty_subpage_buffers(), to iterate through all
dirty extent buffers in one bvec.
Also extract the code of calculating csum for one extent buffer into
csum_one_extent_buffer(), so that both the existing csum_dirty_buffer()
and the new csum_dirty_subpage_buffers() can reuse the same routine.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For btree_set_page_dirty(), we should also check the extent buffer
sanity for subpage support.
Unlike the regular sector size case, since one page can contain multiple
extent buffers, we need to make sure there is at least one dirty extent
buffer in the page.
So this patch will iterate through the btrfs_subpage::dirty_bitmap
to get the extent buffers, and check if any dirty extent buffer in the page
range has EXTENT_BUFFER_DIRTY and proper refs.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduces the following functions to handle subpage writeback status:
- btrfs_subpage_set_writeback()
- btrfs_subpage_clear_writeback()
- btrfs_subpage_test_writeback()
These helpers can only be called when the range is ensured to be
inside the page.
- btrfs_page_set_writeback()
- btrfs_page_clear_writeback()
- btrfs_page_test_writeback()
These helpers can handle both regular sector size and subpage without
problem.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce the following functions to handle subpage dirty status:
- btrfs_subpage_set_dirty()
- btrfs_subpage_clear_dirty()
- btrfs_subpage_test_dirty()
These helpers can only be called when the range is ensured to be
inside the page.
- btrfs_page_set_dirty()
- btrfs_page_clear_dirty()
- btrfs_page_test_dirty()
These helpers can handle both regular sector size and subpage without
problem.
Thus they would be used to replace PageDirty() related calls in
later patches.
There is one special point to note here, just like set_page_dirty() and
clear_page_dirty_for_io(), btrfs_*page_set_dirty() and
btrfs_*page_clear_dirty() must be called with page locked.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_invalidatepage() we re-declare @tree variable as
btrfs_ordered_inode_tree.
Since it's only used to do the spinlock, we can grab it from inode
directly, and remove the unnecessary declaration completely.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_invalidatepage() we introduce a temporary variable, new_len, to
update ordered->truncated_len. But we can use min() to replace it
completely and no need for the variable.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Export supported sector sizes in /sys/fs/btrfs/features/supported_sectorsizes.
Currently all architectures have PAGE_SIZE, There's some disparity
between read-only and read-write support but that will be unified in the
future so there's only one file exporting the size.
The read-only support for systems with 64K pages also works for 4K
sector size.
This new sysfs interface would help eg. mkfs.btrfs to print more
accurate warnings about potentially incompatible option combinations.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently a full send operation uses the standard btree readahead when
iterating over the subvolume/snapshot btree, which despite bringing good
performance benefits, it could be improved in a few aspects for use cases
such as full send operations, which are guaranteed to visit every node
and leaf of a btree, in ascending and sequential order. The limitations
of that standard btree readahead implementation are the following:
1) It only triggers readahead for leaves that are physically close
to the leaf being read, within a 64K range;
2) It only triggers readahead for the next or previous leaves if the
leaf being read is not currently in memory;
3) It never triggers readahead for nodes.
So add a new readahead mode that addresses all these points and use it
for full send operations.
The following test script was used to measure the improvement on a box
using an average, consumer grade, spinning disk and with 16GiB of RAM:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
MKFS_OPTIONS="--nodesize 16384" # default, just to be explicit
MOUNT_OPTIONS="-o max_inline=2048" # default, just to be explicit
mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
# Create files with inline data to make it easier and faster to create
# large btrees.
add_files()
{
local total=$1
local start_offset=$2
local number_jobs=$3
local total_per_job=$(($total / $number_jobs))
echo "Creating $total new files using $number_jobs jobs"
for ((n = 0; n < $number_jobs; n++)); do
(
local start_num=$(($start_offset + $n * $total_per_job))
for ((i = 1; i <= $total_per_job; i++)); do
local file_num=$((start_num + $i))
local file_path="$MNT/file_${file_num}"
xfs_io -f -c "pwrite -S 0xab 0 2000" $file_path > /dev/null
if [ $? -ne 0 ]; then
echo "Failed creating file $file_path"
break
fi
done
) &
worker_pids[$n]=$!
done
wait ${worker_pids[@]}
sync
echo
echo "btree node/leaf count: $(btrfs inspect-internal dump-tree -t 5 $DEV | egrep '^(node|leaf) ' | wc -l)"
}
initial_file_count=500000
add_files $initial_file_count 0 4
echo
echo "Creating first snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap1
echo
echo "Adding more files..."
add_files $((initial_file_count / 4)) $initial_file_count 4
echo
echo "Updating 1/50th of the initial files..."
for ((i = 1; i < $initial_file_count; i += 50)); do
xfs_io -c "pwrite -S 0xcd 0 20" $MNT/file_$i > /dev/null
done
echo
echo "Creating second snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap2
umount $MNT
echo 3 > /proc/sys/vm/drop_caches
blockdev --flushbufs $DEV &> /dev/null
hdparm -F $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
echo
echo "Testing full send..."
start=$(date +%s)
btrfs send $MNT/snap1 > /dev/null
end=$(date +%s)
echo
echo "Full send took $((end - start)) seconds"
umount $MNT
The durations of the full send operation in seconds were the following:
Before this change: 217 seconds
After this change: 205 seconds (-5.7%)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we are running out of space for updating the chunk tree, that is,
when we are low on available space in the system space info, if we have
many task concurrently allocating block groups, via fallocate for example,
many of them can end up all allocating new system chunks when only one is
needed. In extreme cases this can lead to exhaustion of the system chunk
array, which has a size limit of 2048 bytes, and results in a transaction
abort with errno EFBIG, producing a trace in dmesg like the following,
which was triggered on a PowerPC machine with a node/leaf size of 64K:
[1359.518899] ------------[ cut here ]------------
[1359.518980] BTRFS: Transaction aborted (error -27)
[1359.519135] WARNING: CPU: 3 PID: 16463 at ../fs/btrfs/block-group.c:1968 btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs]
[1359.519152] Modules linked in: (...)
[1359.519239] Supported: Yes, External
[1359.519252] CPU: 3 PID: 16463 Comm: stress-ng Tainted: G X 5.3.18-47-default #1 SLE15-SP3
[1359.519274] NIP: c008000000e36fe8 LR: c008000000e36fe4 CTR: 00000000006de8e8
[1359.519293] REGS: c00000056890b700 TRAP: 0700 Tainted: G X (5.3.18-47-default)
[1359.519317] MSR: 800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 48008222 XER: 00000007
[1359.519356] CFAR: c00000000013e170 IRQMASK: 0
[1359.519356] GPR00: c008000000e36fe4 c00000056890b990 c008000000e83200 0000000000000026
[1359.519356] GPR04: 0000000000000000 0000000000000000 0000d52a3b027651 0000000000000007
[1359.519356] GPR08: 0000000000000003 0000000000000001 0000000000000007 0000000000000000
[1359.519356] GPR12: 0000000000008000 c00000063fe44600 000000001015e028 000000001015dfd0
[1359.519356] GPR16: 000000000000404f 0000000000000001 0000000000010000 0000dd1e287affff
[1359.519356] GPR20: 0000000000000001 c000000637c9a000 ffffffffffffffe5 0000000000000000
[1359.519356] GPR24: 0000000000000004 0000000000000000 0000000000000100 ffffffffffffffc0
[1359.519356] GPR28: c000000637c9a000 c000000630e09230 c000000630e091d8 c000000562188b08
[1359.519561] NIP [c008000000e36fe8] btrfs_create_pending_block_groups+0x340/0x3c0 [btrfs]
[1359.519613] LR [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs]
[1359.519626] Call Trace:
[1359.519671] [c00000056890b990] [c008000000e36fe4] btrfs_create_pending_block_groups+0x33c/0x3c0 [btrfs] (unreliable)
[1359.519729] [c00000056890ba90] [c008000000d68d44] __btrfs_end_transaction+0xbc/0x2f0 [btrfs]
[1359.519782] [c00000056890bae0] [c008000000e309ac] btrfs_alloc_data_chunk_ondemand+0x154/0x610 [btrfs]
[1359.519844] [c00000056890bba0] [c008000000d8a0fc] btrfs_fallocate+0xe4/0x10e0 [btrfs]
[1359.519891] [c00000056890bd00] [c0000000004a23b4] vfs_fallocate+0x174/0x350
[1359.519929] [c00000056890bd50] [c0000000004a3cf8] ksys_fallocate+0x68/0xf0
[1359.519957] [c00000056890bda0] [c0000000004a3da8] sys_fallocate+0x28/0x40
[1359.519988] [c00000056890bdc0] [c000000000038968] system_call_exception+0xe8/0x170
[1359.520021] [c00000056890be20] [c00000000000cb70] system_call_common+0xf0/0x278
[1359.520037] Instruction dump:
[1359.520049] 7d0049ad 40c2fff4 7c0004ac 71490004 40820024 2f83fffb 419e0048 3c620000
[1359.520082] e863bcb8 7ec4b378 48010d91 e8410018 <0fe00000> 3c820000 e884bcc8 7ec6b378
[1359.520122] ---[ end trace d6c186e151022e20 ]---
The following steps explain how we can end up in this situation:
1) Task A is at check_system_chunk(), either because it is allocating a
new data or metadata block group, at btrfs_chunk_alloc(), or because
it is removing a block group or turning a block group RO. It does not
matter why;
2) Task A sees that there is not enough free space in the system
space_info object, that is 'left' is < 'thresh'. And at this point
the system space_info has a value of 0 for its 'bytes_may_use'
counter;
3) As a consequence task A calls btrfs_alloc_chunk() in order to allocate
a new system block group (chunk) and then reserves 'thresh' bytes in
the chunk block reserve with the call to btrfs_block_rsv_add(). This
changes the chunk block reserve's 'reserved' and 'size' counters by an
amount of 'thresh', and changes the 'bytes_may_use' counter of the
system space_info object from 0 to 'thresh'.
Also during its call to btrfs_alloc_chunk(), we end up increasing the
value of the 'total_bytes' counter of the system space_info object by
8MiB (the size of a system chunk stripe). This happens through the
call chain:
btrfs_alloc_chunk()
create_chunk()
btrfs_make_block_group()
btrfs_update_space_info()
4) After it finishes the first phase of the block group allocation, at
btrfs_chunk_alloc(), task A unlocks the chunk mutex;
5) At this point the new system block group was added to the transaction
handle's list of new block groups, but its block group item, device
items and chunk item were not yet inserted in the extent, device and
chunk trees, respectively. That only happens later when we call
btrfs_finish_chunk_alloc() through a call to
btrfs_create_pending_block_groups();
Note that only when we update the chunk tree, through the call to
btrfs_finish_chunk_alloc(), we decrement the 'reserved' counter
of the chunk block reserve as we COW/allocate extent buffers,
through:
btrfs_alloc_tree_block()
btrfs_use_block_rsv()
btrfs_block_rsv_use_bytes()
And the system space_info's 'bytes_may_use' is decremented everytime
we allocate an extent buffer for COW operations on the chunk tree,
through:
btrfs_alloc_tree_block()
btrfs_reserve_extent()
find_free_extent()
btrfs_add_reserved_bytes()
If we end up COWing less chunk btree nodes/leaves than expected, which
is the typical case since the amount of space we reserve is always
pessimistic to account for the worst possible case, we release the
unused space through:
btrfs_create_pending_block_groups()
btrfs_trans_release_chunk_metadata()
btrfs_block_rsv_release()
block_rsv_release_bytes()
btrfs_space_info_free_bytes_may_use()
But before task A gets into btrfs_create_pending_block_groups()...
6) Many other tasks start allocating new block groups through fallocate,
each one does the first phase of block group allocation in a
serialized way, since btrfs_chunk_alloc() takes the chunk mutex
before calling check_system_chunk() and btrfs_alloc_chunk().
However before everyone enters the final phase of the block group
allocation, that is, before calling btrfs_create_pending_block_groups(),
new tasks keep coming to allocate new block groups and while at
check_system_chunk(), the system space_info's 'bytes_may_use' keeps
increasing each time a task reserves space in the chunk block reserve.
This means that eventually some other task can end up not seeing enough
free space in the system space_info and decide to allocate yet another
system chunk.
This may repeat several times if yet more new tasks keep allocating
new block groups before task A, and all the other tasks, finish the
creation of the pending block groups, which is when reserved space
in excess is released. Eventually this can result in exhaustion of
system chunk array in the superblock, with btrfs_add_system_chunk()
returning EFBIG, resulting later in a transaction abort.
Even when we don't reach the extreme case of exhausting the system
array, most, if not all, unnecessarily created system block groups
end up being unused since when finishing creation of the first
pending system block group, the creation of the following ones end
up not needing to COW nodes/leaves of the chunk tree, so we never
allocate and deallocate from them, resulting in them never being
added to the list of unused block groups - as a consequence they
don't get deleted by the cleaner kthread - the only exceptions are
if we unmount and mount the filesystem again, which adds any unused
block groups to the list of unused block groups, if a scrub is
run, which also adds unused block groups to the unused list, and
under some circumstances when using a zoned filesystem or async
discard, which may also add unused block groups to the unused list.
So fix this by:
*) Tracking the number of reserved bytes for the chunk tree per
transaction, which is the sum of reserved chunk bytes by each
transaction handle currently being used;
*) When there is not enough free space in the system space_info,
if there are other transaction handles which reserved chunk space,
wait for some of them to complete in order to have enough excess
reserved space released, and then try again. Otherwise proceed with
the creation of a new system chunk.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we reflink to or from a file opened with O_SYNC/O_DSYNC or to/from a
file that has the S_SYNC attribute set, we totally ignore that and do not
durably persist the reflink changes. Since a reflink can change the data
readable from a file (and mtime/ctime, or a file size), it makes sense to
durably persist (fsync) the source and destination files/ranges.
This was previously discussed at:
https://lore.kernel.org/linux-btrfs/20200903035225.GJ6090@magnolia/
The recently introduced test case generic/628, from fstests, exercises
these scenarios and currently fails without this change.
So make sure we fsync the source and destination files/ranges when either
of them was opened with O_SYNC/O_DSYNC or has the S_SYNC attribute set,
just like XFS already does.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
gcc complains that the ctl->max_chunk_size member might be used
uninitialized when none of the three conditions for initializing it in
init_alloc_chunk_ctl_policy_zoned() are true:
In function ‘init_alloc_chunk_ctl_policy_zoned’,
inlined from ‘init_alloc_chunk_ctl’ at fs/btrfs/volumes.c:5023:3,
inlined from ‘btrfs_alloc_chunk’ at fs/btrfs/volumes.c:5340:2:
include/linux/compiler-gcc.h:48:45: error: ‘ctl.max_chunk_size’ may be used uninitialized [-Werror=maybe-uninitialized]
4998 | ctl->max_chunk_size = min(limit, ctl->max_chunk_size);
| ^~~
fs/btrfs/volumes.c: In function ‘btrfs_alloc_chunk’:
fs/btrfs/volumes.c:5316:32: note: ‘ctl’ declared here
5316 | struct alloc_chunk_ctl ctl;
| ^~~
If we ever get into this condition, something is seriously
wrong, as validity is checked in the callers
btrfs_alloc_chunk
init_alloc_chunk_ctl
init_alloc_chunk_ctl_policy_zoned
so the same logic as in init_alloc_chunk_ctl_policy_regular()
and a few other places should be applied. This avoids both further
data corruption, and the compile-time warning.
Fixes: 1cd6121f2a ("btrfs: zoned: implement zoned chunk allocator")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In commit d77815461f ("btrfs: Avoid trucating page or punching hole
in a already existed hole."), existing holes can be skipped by calling
find_first_non_hole() to adjust start and len. However, if the given len
is invalid and large, when an EXTENT_MAP_HOLE extent is found, len will
not be set to zero because (em->start + em->len) is less than
(start + len). Then the ret will be 1 but len will not be set to 0.
The propagated non-zero ret will result in fallocate failure.
In the while-loop of btrfs_replace_file_extents(), len is not updated
every time before it calls find_first_non_hole(). That is, after
btrfs_drop_extents() successfully drops the last non-hole file extent,
it may fail with ENOSPC when attempting to drop a file extent item
representing a hole. The problem can happen. After it calls
find_first_non_hole(), the cur_offset will be adjusted to be larger
than or equal to end. However, since the len is not set to zero, the
break-loop condition (ret && !len) will not be met. After it leaves the
while-loop, fallocate will return 1, which is an unexpected return
value.
We're not able to construct a reproducible way to let
btrfs_drop_extents() fail with ENOSPC after it drops the last non-hole
file extent but with remaining holes left. However, it's quite easy to
fix. We just need to update and check the len every time before we call
find_first_non_hole(). To make the while loop more readable, we also
pull the variable updates to the bottom of loop like this:
while (cur_offset < end) {
...
// update cur_offset & len
// advance cur_offset & len in hole-punching case if needed
}
Reported-by: Robbie Ko <robbieko@synology.com>
Fixes: d77815461f ("btrfs: Avoid trucating page or punching hole in a already existed hole.")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 6e37d24599 ("btrfs: zoned: fix deadlock on log sync") pointed out
a deadlock warning and removed mutex_{lock,unlock} of fs_info::tree_root->log_mutex.
While it looks like it always cause a deadlock, we didn't see actual
deadlock in fstests runs. The reason is log_root_tree->log_mutex !=
fs_info->tree_root->log_mutex, not taking the same lock. So, the warning
was actually a false-positive.
Since btrfs_alloc_log_tree_node() is protected only by
fs_info->tree_root->log_mutex, we can (and should) move the code out of
the lock scope of log_root_tree->log_mutex and silence the warning.
Fixes: 6e37d24599 ("btrfs: zoned: fix deadlock on log sync")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a comment at btrfs_replace_file_extents() that mentions that we
set the full sync flag on an inode when cloning into a file with a size
greater than or equals to 16MiB, through try_release_extent_mapping() when
we truncate the page cache after replacing file extents during a clone
operation.
That is not true anymore since commit 5e548b3201 ("btrfs: do not set
the full sync flag on the inode during page release"), so update the
comment to remove that part and rephrase it slightly to make it more
clear why the full sync flag is set at btrfs_replace_file_extents().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_orphan_cleanup() has a comment referring to find_dead_roots, but
function does not exists since commit cb517eabba ("Btrfs: cleanup the
similar code of the fs root read"). What we use now to find and load dead
roots is btrfs_find_orphan_roots(). So update the comment and make it a
bit more detailed about why we can not delete an orphan item for a root.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We used to encode two different numbers in the tree mod log counter used
for sequence numbers, one in the upper 32 bits and the other one in the
lower 32 bits. However that is no longer the case, we stopped doing that
since commit fcebe4562d ("Btrfs: rework qgroup accounting").
So update the debug message at btrfs_check_delayed_seq to stop extracting
the two 32 bits counters and print instead the 64 bits sequence numbers.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two places outside the tree mod log module that extract the
lowest sequence number of the tree mod log. These places end up
duplicating code and open coding the logic and internal implementation
details of the tree mod log. So add a helper to the tree mod log module
and header that returns the lowest sequence number or 0 if there aren't
any tree mod log users at the moment.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_tree_mod_log_free_eb() we check if we are dealing with a leaf,
and if so, return immediately and do nothing. However this check can be
removed, because after it we call tree_mod_need_log(), which returns
false when given an extent buffer that corresponds to a leaf.
So just remove the leaf check and pass the extent buffer to
tree_mod_need_log().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of exposing implementation details of the tree mod log to check
if there are active tree mod log users at btrfs_free_tree_block(), use
the new bit BTRFS_FS_TREE_MOD_LOG_USERS for fs_info->flags instead. This
way extent-tree.c does not need to known about any of the internals of
the tree mod log and avoids taking a lock unnecessarily as well.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The tree modification log functions are called very frequently, basically
they are called every time a btree is modified (a pointer added or removed
to a node, a new root for a btree is set, etc). Because of that, to avoid
heavy lock contention on the lock that protects the list of tree mod log
users, we have checks that test the emptiness of the list with a full
memory barrier before the checks, so that when there are no tree mod log
users we avoid taking the lock.
Replace the memory barrier and list emptiness check with a test for a new
bit set at fs_info->flags. This bit is used to indicate when there are
tree mod log users, set whenever a user is added to the list and cleared
when the last user is removed from the list. This makes the intention a
bit more obvious and possibly more efficient (assuming test_bit() may be
cheaper than a full memory barrier on some architectures).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Several functions of the tree modification log use integers as booleans,
so change them to use booleans instead, making their use more clear.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The tree modification log, which records modifications done to btrees, is
quite large and currently spread all over ctree.c, which is a huge file
already.
To make things better organized, move all that code into its own separate
source and header files. Functions and definitions that are used outside
of the module (mostly by ctree.c) are renamed so that they start with a
"btrfs_" prefix. Everything else remains unchanged.
This makes it easier to go over the tree modification log code every
time I need to go read it to fix a bug.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment updates ]
Signed-off-by: David Sterba <dsterba@suse.com>
btrfsic_read_block() (which calls kmap()) and
btrfsic_release_block_ctx() (which calls kunmap()) are always called
within a single thread of execution.
Therefore the mappings created within these calls can be a thread local
mapping.
Convert the kmap() of bloc_ctx->pagev to kmap_local_page(). Luckily the
unmap loops backwards through the array pointer so no adjustment needs
to be made to the unmapping order.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Again there is an array of pointers which must be unmapped in the correct
order.
Convert the kmap()'s to kmap_local_page() and adjust the unmapping
to work backwards through the unmapping loop.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These kmaps are thread local and don't need to be atomic. So they can use
the more efficient kmap_local_page(). However, the mapping of pages in
the stripes and the additional parity and qstripe pages are a bit
trickier because the unmapping must occur in the opposite order from the
mapping. Furthermore, the pointer array in __raid_recover_end_io() may
get reordered.
Convert these calls to kmap_local_page() taking care to reverse the
unmappings of any page arrays as well as being careful with the mappings
of any special pages such as the parity and qstripe pages.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Use a simple coccinelle script to help convert the most common
kmap()/kunmap() patterns to kmap_local_page()/kunmap_local().
Note that some kmaps which were caught by this script needed to be
handled by hand because of the strict unmapping order of kunmap_local()
so they are not included in this patch. But this script got us started.
There's another temp variable added for the final length write to the
first page so it does not interfere with cpage_out that is used for
mapping other pages.
The development of this patch was aided by the follow script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap and replace with kmap_local_page then mark kunmap
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
@ catch_all @
expression e, e2;
@@
(
-kmap(e)
+kmap_local_page(e)
)
...
(
-kunmap(...)
+kunmap_local()
)
// </smpl>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The in_range() macro is defined twice in btrfs' source, once in ctree.h
and once in misc.h.
Remove the definition in ctree.h and include misc.h in the files depending
on it.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_inode_in_log() checks the list of modified extents of the
inode, and has a comment mentioning why, as it used to be necessary to
make sure if we did something like the following:
mmap write range A
mmap write range B
msync range A (ranged fsync)
msync range B (ranged fsync)
we ended up with both ranges being logged.
If we did not check it, then the second fsync would do nothing because
btrfs_inode_in_log() would return true. This was added in 125c4cf9f3
("Btrfs: set inode's logged_trans/last_log_commit after ranged fsync") and
test case generic/325 from fstests exercises that scenario.
However, as of commit 487781796d ("btrfs: make fast fsyncs wait only
for writeback"), every ranged fsync is now turned into a full ranged fsync
(operates on the range from 0 to LLONG_MAX), so it is now pointless to
test of emptiness of the list of modified extents, and the comment is
clearly outdated.
So just remove the comment and list emptiness check, while also changing
the function's return type to be a boolean instead of an integer.
In case one day we get support for ranged fsyncs again, it will be easy
to notice the check is necessary again, because it will make generic/325
always fail.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a race between marking that an inode needs to be logged, either
at btrfs_set_inode_last_trans() or at btrfs_page_mkwrite(), and between
btrfs_sync_log(). The following steps describe how the race happens.
1) We are at transaction N;
2) Inode I was previously fsynced in the current transaction so it has:
inode->logged_trans set to N;
3) The inode's root currently has:
root->log_transid set to 1
root->last_log_commit set to 0
Which means only one log transaction was committed to far, log
transaction 0. When a log tree is created we set ->log_transid and
->last_log_commit of its parent root to 0 (at btrfs_add_log_tree());
4) One more range of pages is dirtied in inode I;
5) Some task A starts an fsync against some other inode J (same root), and
so it joins log transaction 1.
Before task A calls btrfs_sync_log()...
6) Task B starts an fsync against inode I, which currently has the full
sync flag set, so it starts delalloc and waits for the ordered extent
to complete before calling btrfs_inode_in_log() at btrfs_sync_file();
7) During ordered extent completion we have btrfs_update_inode() called
against inode I, which in turn calls btrfs_set_inode_last_trans(),
which does the following:
spin_lock(&inode->lock);
inode->last_trans = trans->transaction->transid;
inode->last_sub_trans = inode->root->log_transid;
inode->last_log_commit = inode->root->last_log_commit;
spin_unlock(&inode->lock);
So ->last_trans is set to N and ->last_sub_trans set to 1.
But before setting ->last_log_commit...
8) Task A is at btrfs_sync_log():
- it increments root->log_transid to 2
- starts writeback for all log tree extent buffers
- waits for the writeback to complete
- writes the super blocks
- updates root->last_log_commit to 1
It's a lot of slow steps between updating root->log_transid and
root->last_log_commit;
9) The task doing the ordered extent completion, currently at
btrfs_set_inode_last_trans(), then finally runs:
inode->last_log_commit = inode->root->last_log_commit;
spin_unlock(&inode->lock);
Which results in inode->last_log_commit being set to 1.
The ordered extent completes;
10) Task B is resumed, and it calls btrfs_inode_in_log() which returns
true because we have all the following conditions met:
inode->logged_trans == N which matches fs_info->generation &&
inode->last_subtrans (1) <= inode->last_log_commit (1) &&
inode->last_subtrans (1) <= root->last_log_commit (1) &&
list inode->extent_tree.modified_extents is empty
And as a consequence we return without logging the inode, so the
existing logged version of the inode does not point to the extent
that was written after the previous fsync.
It should be impossible in practice for one task be able to do so much
progress in btrfs_sync_log() while another task is at
btrfs_set_inode_last_trans() right after it reads root->log_transid and
before it reads root->last_log_commit. Even if kernel preemption is enabled
we know the task at btrfs_set_inode_last_trans() can not be preempted
because it is holding the inode's spinlock.
However there is another place where we do the same without holding the
spinlock, which is in the memory mapped write path at:
vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
{
(...)
BTRFS_I(inode)->last_trans = fs_info->generation;
BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
(...)
So with preemption happening after setting ->last_sub_trans and before
setting ->last_log_commit, it is less of a stretch to have another task
do enough progress at btrfs_sync_log() such that the task doing the memory
mapped write ends up with ->last_sub_trans and ->last_log_commit set to
the same value. It is still a big stretch to get there, as the task doing
btrfs_sync_log() has to start writeback, wait for its completion and write
the super blocks.
So fix this in two different ways:
1) For btrfs_set_inode_last_trans(), simply set ->last_log_commit to the
value of ->last_sub_trans minus 1;
2) For btrfs_page_mkwrite() only set the inode's ->last_sub_trans, just
like we do for buffered and direct writes at btrfs_file_write_iter(),
which is all we need to make sure multiple writes and fsyncs to an
inode in the same transaction never result in an fsync missing that
the inode changed and needs to be logged. Turn this into a helper
function and use it both at btrfs_page_mkwrite() and at
btrfs_file_write_iter() - this also fixes the problem that at
btrfs_page_mkwrite() we were setting those fields without the
protection of the inode's spinlock.
This is an extremely unlikely race to happen in practice.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing an fsync we flush all delalloc, lock the inode (VFS lock), flush
any new delalloc that might have been created before taking the lock and
then wait either for the ordered extents to complete or just for the
writeback to complete (depending on whether the full sync flag is set or
not). We then start logging the inode and assume that while we are doing it
no one else is touching the inode's file extent items (or adding new ones).
That is generally true because all operations that modify an inode acquire
the inode's lock first, including buffered and direct IO writes. However
there is one exception: memory mapped writes, which do not and can not
acquire the inode's lock.
This can cause two types of issues: ending up logging file extent items
with overlapping ranges, which is detected by the tree checker and will
result in aborting the transaction when starting writeback for a log
tree's extent buffers, or a silent corruption where we log a version of
the file that never existed.
Scenario 1 - logging overlapping extents
The following steps explain how we can end up with file extents items with
overlapping ranges in a log tree due to a race between a fsync and memory
mapped writes:
1) Task A starts an fsync on inode X, which has the full sync runtime flag
set. First it starts by flushing all delalloc for the inode;
2) Task A then locks the inode and flushes any other delalloc that might
have been created after the previous flush and waits for all ordered
extents to complete;
3) In the inode's root we have the following leaf:
Leaf N, generation == current transaction id:
---------------------------------------------------------
| (...) [ file extent item, offset 640K, length 128K ] |
---------------------------------------------------------
The last file extent item in leaf N covers the file range from 640K to
768K;
4) Task B does a memory mapped write for the page corresponding to the
file range from 764K to 768K;
5) Task A starts logging the inode. At copy_inode_items_to_log() it uses
btrfs_search_forward() to search for leafs modified in the current
transaction that contain items for the inode. It finds leaf N and copies
all the inode items from that leaf into the log tree.
Now the log tree has a copy of the last file extent item from leaf N.
At the end of the while loop at copy_inode_items_to_log(), we have the
minimum key set to:
min_key.objectid = <inode X number>
min_key.type = BTRFS_EXTENT_DATA_KEY
min_key.offset = 640K
Then we increment the key's offset by 1 so that the next call to
btrfs_search_forward() leaves us at the first key greater than the key
we just processed.
But before btrfs_search_forward() is called again...
6) Dellaloc for the page at offset 764K, dirtied by task B, is started.
It can be started for several reasons:
- The async reclaim task is attempting to satisfy metadata or data
reservation requests, and it has reached a point where it decided
to flush delalloc;
- Due to memory pressure the VMM triggers writeback of dirty pages;
- The system call sync_file_range(2) is called from user space.
7) When the respective ordered extent completes, it trims the length of
the existing file extent item for file offset 640K from 128K to 124K,
and a new file extent item is added with a key offset of 764K and a
length of 4K;
8) Task A calls btrfs_search_forward(), which returns us a path pointing
to the leaf (can be leaf N or some other) containing the new file extent
item for file offset 764K.
We end up copying this item to the log tree, which overlaps with the
last copied file extent item, which covers the file range from 640K to
768K.
When writeback is triggered for log tree's extent buffers, the issue
will be detected by the tree checker which will dump a trace and an
error message on dmesg/syslog. If the writeback is triggered when
syncing the log, which typically is, then we also end up aborting the
current transaction.
This is the same type of problem fixed in 0c713cbab6 ("Btrfs: fix race
between ranged fsync and writeback of adjacent ranges").
Scenario 2 - logging a version of the file that never existed
This scenario only happens when using the NO_HOLES feature and results in
a silent corruption, in the sense that is not detectable by 'btrfs check'
or the tree checker:
1) We have an inode I with a size of 1M and two file extent items, one
covering an extent with disk_bytenr == X for the file range [0, 512K)
and another one covering another extent with disk_bytenr == Y for the
file range [512K, 1M);
2) A hole is punched for the file range [512K, 1M);
3) Task A starts an fsync of inode I, which has the full sync runtime flag
set. It starts by flushing all existing delalloc, locks the inode (VFS
lock), starts any new delalloc that might have been created before
taking the lock and waits for all ordered extents to complete;
4) Some other task does a memory mapped write for the page corresponding to
the file range [640K, 644K) for example;
5) Task A then logs all items of the inode with the call to
copy_inode_items_to_log();
6) In the meanwhile delalloc for the range [640K, 644K) is started. It can
be started for several reasons:
- The async reclaim task is attempting to satisfy metadata or data
reservation requests, and it has reached a point where it decided
to flush delalloc;
- Due to memory pressure the VMM triggers writeback of dirty pages;
- The system call sync_file_range(2) is called from user space.
7) The ordered extent for the range [640K, 644K) completes and a file
extent item for that range is added to the subvolume tree, pointing
to a 4K extent with a disk_bytenr == Z;
8) Task A then calls btrfs_log_holes(), to scan for implicit holes in
the subvolume tree. It finds two implicit holes:
- one for the file range [512K, 640K)
- one for the file range [644K, 1M)
As a result we end up neither logging a hole for the range [640K, 644K)
nor logging the file extent item with a disk_bytenr == Z.
This means that if we have a power failure and replay the log tree we
end up getting the following file extent layout:
[ disk_bytenr X ] [ hole ] [ disk_bytenr Y ] [ hole ]
0 512K 512K 640K 640K 644K 644K 1M
Which does not corresponding to any layout the file ever had before
the power failure. The only two valid layouts would be:
[ disk_bytenr X ] [ hole ]
0 512K 512K 1M
and
[ disk_bytenr X ] [ hole ] [ disk_bytenr Z ] [ hole ]
0 512K 512K 640K 640K 644K 644K 1M
This can be fixed by serializing memory mapped writes with fsync, and there
are two ways to do it:
1) Make a fsync lock the entire file range, from 0 to (u64)-1 / LLONG_MAX
in the inode's io tree. This prevents the race but also blocks any reads
during the duration of the fsync, which has a negative impact for many
common workloads;
2) Make an fsync write lock the i_mmap_lock semaphore in the inode. This
semaphore was recently added by Josef's patch set:
btrfs: add a i_mmap_lock to our inode
btrfs: cleanup inode_lock/inode_unlock uses
btrfs: exclude mmaps while doing remap
btrfs: exclude mmap from happening during all fallocate operations
and is used to solve races between memory mapped writes and
clone/dedupe/fallocate. This also makes us have the same behaviour we
have regarding other writes (buffered and direct IO) and fsync - block
them while the inode logging is in progress.
This change uses the second approach due to the performance impact of the
first one.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's a small window where a deadlock can happen between fallocate and
mmap. This is described in detail by Filipe:
"""
When doing a fallocate operation we lock the inode, flush delalloc within
the target range, wait for any ordered extents to complete and then lock
the file range. Before we lock the range and after we flush delalloc,
there is a time window where another task can come in and do a memory
mapped write for a page within the fallocate range.
This means that after fallocate locks the range, there can be a dirty page
in the range. More often than not, this does not cause any problem.
The exception is when we are low on available metadata space, because an
fallocate operation needs to start a transaction while holding the file
range locked, either through btrfs_prealloc_file_range() or through the
call to btrfs_fallocate_update_isize(). If that's the case, we can end up
in a deadlock. The following list of steps explains how that happens:
1) A fallocate operation starts, locks the inode, flushes delalloc in the
range and waits for ordered extents in the range to complete;
2) Before the fallocate task locks the file range, another task does a
memory mapped write for a page in the fallocate target range. This is
possible since memory mapped writes do not (and can not) lock the
inode;
3) The fallocate task locks the file range. At this point there is one
dirty page in the range (due to the memory mapped write);
4) When the fallocate task attempts to start a transaction, it blocks when
attempting to reserve metadata space, since we are low on available
metadata space. Before blocking (wait on its reservation ticket), it
starts the async reclaim task (if not running already);
5) The async reclaim task is not able to release space through any other
means, so it decides to flush delalloc for inodes with dirty pages.
It finds that the inode used in the fallocate operation has a dirty
page and therefore queues a job (fs_info->flush_workers workqueue) to
flush delalloc for that inode and waits on that job to complete;
6) The flush job blocks when attempting to lock the file range because
it is currently locked by the fallocate task;
7) The fallocate task keeps waiting for its metadata reservation, waiting
for a wakeup on its reservation ticket. The async reclaim task is
waiting on the flush job, which in turn is waiting for locking the file
range that is currently locked by the fallocate task. So unless some
other task is able to release enough metadata space, for example an
ordered extent for some other inode completes, we end up in a deadlock
between all these tasks.
When this happens stack traces like the following show up in dmesg/syslog:
INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000
Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
schedule+0x45/0xe0
lock_extent_bits+0x1e6/0x2d0 [btrfs]
? finish_wait+0x90/0x90
btrfs_invalidatepage+0x32c/0x390 [btrfs]
? __mod_memcg_state+0x8e/0x160
__extent_writepage+0x2d4/0x400 [btrfs]
extent_write_cache_pages+0x2b2/0x500 [btrfs]
? lock_release+0x20e/0x4c0
? trace_hardirqs_on+0x1b/0xf0
extent_writepages+0x43/0x90 [btrfs]
? lock_acquire+0x1a3/0x490
do_writepages+0x43/0xe0
? __filemap_fdatawrite_range+0xa4/0x100
__filemap_fdatawrite_range+0xc5/0x100
btrfs_run_delalloc_work+0x17/0x40 [btrfs]
btrfs_work_helper+0xf1/0x600 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x50/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000
Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
? kvm_clock_read+0x14/0x30
? wait_for_completion+0x81/0x110
schedule+0x45/0xe0
schedule_timeout+0x30c/0x580
? _raw_spin_unlock_irqrestore+0x3c/0x60
? lock_acquire+0x1a3/0x490
? try_to_wake_up+0x7a/0xa20
? lock_release+0x20e/0x4c0
? lock_acquired+0x199/0x490
? wait_for_completion+0x81/0x110
wait_for_completion+0xab/0x110
start_delalloc_inodes+0x2af/0x390 [btrfs]
btrfs_start_delalloc_roots+0x12d/0x250 [btrfs]
flush_space+0x24f/0x660 [btrfs]
btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x20f/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
(...)
several tasks waiting for the inode lock held by the fallocate task below
(...)
RIP: 0033:0x7f61efe73fff
Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5.
RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff
RDX: 00000000ffffff9c RSI: 0000560fbd5d90a0 RDI: 00000000ffffff9c
RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003
R10: 0000560fbd5d7ad0 R11: 0000000000000202 R12: 0000000000000001
R13: 000000000000005e R14: 00007ffc3371bea0 R15: 00007ffc3371beb0
task:fdm-stress state:D stack: 0 pid:2508243 ppid:2508153 flags:0x00000000
Call Trace:
__schedule+0x5d1/0xcf0
? _raw_spin_unlock_irqrestore+0x3c/0x60
schedule+0x45/0xe0
__reserve_bytes+0x4a4/0xb10 [btrfs]
? finish_wait+0x90/0x90
btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs]
btrfs_block_rsv_add+0x1f/0x50 [btrfs]
start_transaction+0x2d1/0x760 [btrfs]
btrfs_replace_file_extents+0x120/0x930 [btrfs]
? btrfs_fallocate+0xdcf/0x1260 [btrfs]
btrfs_fallocate+0xdfb/0x1260 [btrfs]
? filename_lookup+0xf1/0x180
vfs_fallocate+0x14f/0x440
ioctl_preallocate+0x92/0xc0
do_vfs_ioctl+0x66b/0x750
? __do_sys_newfstat+0x53/0x60
__x64_sys_ioctl+0x62/0xb0
do_syscall_64+0x33/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
"""
Fix this by disallowing mmaps from happening while we're doing any of
the fallocate operations on this inode.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Darrick reported a potential issue to me where we could allow mmap
writes after validating a page range matched in the case of dedupe.
Generally we rely on lock page -> lock extent with the ordered flush to
protect us, but this is done after we check the pages because we use the
generic helpers, so we could modify the page in between doing the check
and locking the range.
There also exists a deadlock, as described by Filipe
"""
When cloning a file range, we lock the inodes, flush any delalloc within
the respective file ranges, wait for any ordered extents and then lock the
file ranges in both inodes. This means that right after we flush delalloc
and before we lock the file ranges, memory mapped writes can come in and
dirty pages in the file ranges of the clone operation.
Most of the time this is harmless and causes no problems. However, if we
are low on available metadata space, we can later end up in a deadlock
when starting a transaction to replace file extent items. This happens if
when allocating metadata space for the transaction, we need to wait for
the async reclaim thread to release space and the reclaim thread needs to
flush delalloc for the inode that got the memory mapped write and has its
range locked by the clone task.
Basically what happens is the following:
1) A clone operation locks inodes A and B, flushes delalloc for both
inodes in the respective file ranges and waits for any ordered extents
in those ranges to complete;
2) Before the clone task locks the file ranges, another task does a
memory mapped write (which does not lock the inode) for one of the
inodes of the clone operation. So now we have a dirty page in one of
the ranges used by the clone operation;
3) The clone operation locks the file ranges for inodes A and B;
4) Later, when iterating over the file extents of inode A, the clone
task attempts to start a transaction. There's not enough available
free metadata space, so the async reclaim task is started (if not
running already) and we wait for someone to wake us up on our
reservation ticket;
5) The async reclaim task is not able to release space by any other
means and decides to flush delalloc for the inode of the clone
operation;
6) The workqueue job used to flush the inode blocks when starting
delalloc for the inode, since the file range is currently locked by
the clone task;
7) But the clone task is waiting on its reservation ticket and the async
reclaim task is waiting on the flush job to complete, which can't
progress since the clone task has the file range locked. So unless
some other task is able to release space, for example an ordered
extent for some other inode completes, we have a deadlock between all
these tasks;
When this happens stack traces like the following show up in dmesg/syslog:
INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000
Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
schedule+0x45/0xe0
lock_extent_bits+0x1e6/0x2d0 [btrfs]
? finish_wait+0x90/0x90
btrfs_invalidatepage+0x32c/0x390 [btrfs]
? __mod_memcg_state+0x8e/0x160
__extent_writepage+0x2d4/0x400 [btrfs]
extent_write_cache_pages+0x2b2/0x500 [btrfs]
? lock_release+0x20e/0x4c0
? trace_hardirqs_on+0x1b/0xf0
extent_writepages+0x43/0x90 [btrfs]
? lock_acquire+0x1a3/0x490
do_writepages+0x43/0xe0
? __filemap_fdatawrite_range+0xa4/0x100
__filemap_fdatawrite_range+0xc5/0x100
btrfs_run_delalloc_work+0x17/0x40 [btrfs]
btrfs_work_helper+0xf1/0x600 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x50/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000
Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
? kvm_clock_read+0x14/0x30
? wait_for_completion+0x81/0x110
schedule+0x45/0xe0
schedule_timeout+0x30c/0x580
? _raw_spin_unlock_irqrestore+0x3c/0x60
? lock_acquire+0x1a3/0x490
? try_to_wake_up+0x7a/0xa20
? lock_release+0x20e/0x4c0
? lock_acquired+0x199/0x490
? wait_for_completion+0x81/0x110
wait_for_completion+0xab/0x110
start_delalloc_inodes+0x2af/0x390 [btrfs]
btrfs_start_delalloc_roots+0x12d/0x250 [btrfs]
flush_space+0x24f/0x660 [btrfs]
btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x20f/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
(...)
several other tasks blocked on inode locks held by the clone task below
(...)
RIP: 0033:0x7f61efe73fff
Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5.
RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff
RDX: 00000000ffffff9c RSI: 0000560fbd604690 RDI: 00000000ffffff9c
RBP: 00007ffc3371beb0 R08: 0000000000000002 R09: 0000560fbd5d75f0
R10: 0000560fbd5d81f0 R11: 0000000000000202 R12: 0000000000000002
R13: 000000000000000b R14: 00007ffc3371bea0 R15: 00007ffc3371beb0
task: fdm-stress state:D stack: 0 pid:2508234 ppid:2508153 flags:0x00004000
Call Trace:
__schedule+0x5d1/0xcf0
? _raw_spin_unlock_irqrestore+0x3c/0x60
schedule+0x45/0xe0
__reserve_bytes+0x4a4/0xb10 [btrfs]
? finish_wait+0x90/0x90
btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs]
btrfs_block_rsv_add+0x1f/0x50 [btrfs]
start_transaction+0x2d1/0x760 [btrfs]
btrfs_replace_file_extents+0x120/0x930 [btrfs]
? lock_release+0x20e/0x4c0
btrfs_clone+0x3e4/0x7e0 [btrfs]
? btrfs_lookup_first_ordered_extent+0x8e/0x100 [btrfs]
btrfs_clone_files+0xf6/0x150 [btrfs]
btrfs_remap_file_range+0x324/0x3d0 [btrfs]
do_clone_file_range+0xd4/0x1f0
vfs_clone_file_range+0x4d/0x230
? lock_release+0x20e/0x4c0
ioctl_file_clone+0x8f/0xc0
do_vfs_ioctl+0x342/0x750
__x64_sys_ioctl+0x62/0xb0
do_syscall_64+0x33/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
"""
Fix both of these issues by excluding mmaps from happening we are doing
any sort of remap, which prevents this race completely.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A few places we intermix btrfs_inode_lock with a inode_unlock, and some
places we just use inode_lock/inode_unlock instead of btrfs_inode_lock.
None of these places are using this incorrectly, but as we adjust some
of these callers it would be nice to keep everything consistent, so
convert everybody to use btrfs_inode_lock/btrfs_inode_unlock.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We need to be able to exclude page_mkwrite from happening concurrently
with certain operations. To facilitate this, add a i_mmap_lock to our
inode, down_read() it in our mkwrite, and add a new ILOCK flag to
indicate that we want to take the i_mmap_lock as well. I used pahole to
check the size of the btrfs_inode, the sizes are as follows
no lockdep:
before: 1120 (3 per 4k page)
after: 1160 (3 per 4k page)
lockdep:
before: 2072 (1 per 4k page)
after: 2224 (1 per 4k page)
We're slightly larger but it doesn't change how many objects we can fit
per page.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The parameter mirror is not used and does not make sense for checksum
verification of the given bio.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
force_cow can be calculated from inode and does not need to be passed as
an argument.
This simplifies run_delalloc_nocow() call from btrfs_run_delalloc_range()
A new function, should_nocow() checks if the range should be NOCOWed or
not. The function returns true iff either BTRFS_INODE_NODATA or
BTRFS_INODE_PREALLOC, but is not a defrag extent.
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix the following coccicheck warnings:
./fs/btrfs/volumes.c:1462:10-11: WARNING: return of 0/1 in function
'dev_extent_hole_check_zoned' with return type bool.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we do not do btree read ahead when doing an incremental send,
however we know that we will read and process any node or leaf in the
send root that has a generation greater than the generation of the parent
root. So triggering read ahead for such nodes and leafs is beneficial
for an incremental send.
This change does that, triggers read ahead of any node or leaf in the
send root that has a generation greater then the generation of the
parent root. As for the parent root, no readahead is triggered because
knowing in advance which nodes/leaves are going to be read is not so
linear and there's often a large time window between visiting nodes or
leaves of the parent root. So I opted to leave out the parent root,
and triggering read ahead for its nodes/leaves seemed to have not made
significant difference.
The following test script was used to measure the improvement on a box
using an average, consumer grade, spinning disk and with 16GiB of ram:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
MKFS_OPTIONS="--nodesize 16384" # default, just to be explicit
MOUNT_OPTIONS="-o max_inline=2048" # default, just to be explicit
mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
# Create files with inline data to make it easier and faster to create
# large btrees.
add_files()
{
local total=$1
local start_offset=$2
local number_jobs=$3
local total_per_job=$(($total / $number_jobs))
echo "Creating $total new files using $number_jobs jobs"
for ((n = 0; n < $number_jobs; n++)); do
(
local start_num=$(($start_offset + $n * $total_per_job))
for ((i = 1; i <= $total_per_job; i++)); do
local file_num=$((start_num + $i))
local file_path="$MNT/file_${file_num}"
xfs_io -f -c "pwrite -S 0xab 0 2000" $file_path > /dev/null
if [ $? -ne 0 ]; then
echo "Failed creating file $file_path"
break
fi
done
) &
worker_pids[$n]=$!
done
wait ${worker_pids[@]}
sync
echo
echo "btree node/leaf count: $(btrfs inspect-internal dump-tree -t 5 $DEV | egrep '^(node|leaf) ' | wc -l)"
}
initial_file_count=500000
add_files $initial_file_count 0 4
echo
echo "Creating first snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap1
echo
echo "Adding more files..."
add_files $((initial_file_count / 4)) $initial_file_count 4
echo
echo "Updating 1/50th of the initial files..."
for ((i = 1; i < $initial_file_count; i += 50)); do
xfs_io -c "pwrite -S 0xcd 0 20" $MNT/file_$i > /dev/null
done
echo
echo "Creating second snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap2
umount $MNT
echo 3 > /proc/sys/vm/drop_caches
blockdev --flushbufs $DEV &> /dev/null
hdparm -F $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
echo
echo "Testing full send..."
start=$(date +%s)
btrfs send $MNT/snap1 > /dev/null
end=$(date +%s)
echo
echo "Full send took $((end - start)) seconds"
umount $MNT
echo 3 > /proc/sys/vm/drop_caches
blockdev --flushbufs $DEV &> /dev/null
hdparm -F $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
echo
echo "Testing incremental send..."
start=$(date +%s)
btrfs send -p $MNT/snap1 $MNT/snap2 > /dev/null
end=$(date +%s)
echo
echo "Incremental send took $((end - start)) seconds"
umount $MNT
Before this change, incremental send duration:
with $initial_file_count == 200000: 51 seconds
with $initial_file_count == 500000: 168 seconds
After this change, incremental send duration:
with $initial_file_count == 200000: 39 seconds (-26.7%)
with $initial_file_count == 500000: 125 seconds (-29.4%)
For $initial_file_count == 200000 there are 62600 nodes and leaves in the
btree of the first snapshot, and 77759 nodes and leaves in the btree of
the second snapshot. The root nodes were at level 2.
While for $initial_file_count == 500000 there are 152476 nodes and leaves
in the btree of the first snapshot, and 190511 nodes and leaves in the
btree of the second snapshot. The root nodes were at level 2 as well.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing a full send we know that we are going to be reading every node
and leaf of the send root, so we benefit from enabling read ahead for the
btree.
This change enables read ahead for full send operations only, incremental
sends will have read ahead enabled in a different way by a separate patch.
The following test script was used to measure the improvement on a box
using an average, consumer grade, spinning disk and with 16GiB of RAM:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
MKFS_OPTIONS="--nodesize 16384" # default, just to be explicit
MOUNT_OPTIONS="-o max_inline=2048" # default, just to be explicit
mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
# Create files with inline data to make it easier and faster to create
# large btrees.
add_files()
{
local total=$1
local start_offset=$2
local number_jobs=$3
local total_per_job=$(($total / $number_jobs))
echo "Creating $total new files using $number_jobs jobs"
for ((n = 0; n < $number_jobs; n++)); do
(
local start_num=$(($start_offset + $n * $total_per_job))
for ((i = 1; i <= $total_per_job; i++)); do
local file_num=$((start_num + $i))
local file_path="$MNT/file_${file_num}"
xfs_io -f -c "pwrite -S 0xab 0 2000" $file_path > /dev/null
if [ $? -ne 0 ]; then
echo "Failed creating file $file_path"
break
fi
done
) &
worker_pids[$n]=$!
done
wait ${worker_pids[@]}
sync
echo
echo "btree node/leaf count: $(btrfs inspect-internal dump-tree -t 5 $DEV | egrep '^(node|leaf) ' | wc -l)"
}
initial_file_count=500000
add_files $initial_file_count 0 4
echo
echo "Creating first snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap1
echo
echo "Adding more files..."
add_files $((initial_file_count / 4)) $initial_file_count 4
echo
echo "Updating 1/50th of the initial files..."
for ((i = 1; i < $initial_file_count; i += 50)); do
xfs_io -c "pwrite -S 0xcd 0 20" $MNT/file_$i > /dev/null
done
echo
echo "Creating second snapshot..."
btrfs subvolume snapshot -r $MNT $MNT/snap2
umount $MNT
echo 3 > /proc/sys/vm/drop_caches
blockdev --flushbufs $DEV &> /dev/null
hdparm -F $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
echo
echo "Testing full send..."
start=$(date +%s)
btrfs send $MNT/snap1 > /dev/null
end=$(date +%s)
echo
echo "Full send took $((end - start)) seconds"
umount $MNT
echo 3 > /proc/sys/vm/drop_caches
blockdev --flushbufs $DEV &> /dev/null
hdparm -F $DEV &> /dev/null
mount $MOUNT_OPTIONS $DEV $MNT
echo
echo "Testing incremental send..."
start=$(date +%s)
btrfs send -p $MNT/snap1 $MNT/snap2 > /dev/null
end=$(date +%s)
echo
echo "Incremental send took $((end - start)) seconds"
umount $MNT
Before this change, full send duration:
with $initial_file_count == 200000: 165 seconds
with $initial_file_count == 500000: 407 seconds
After this change, full send duration:
with $initial_file_count == 200000: 149 seconds (-10.2%)
with $initial_file_count == 500000: 353 seconds (-14.2%)
For $initial_file_count == 200000 there are 62600 nodes and leaves in the
btree of the first snapshot, while for $initial_file_count == 500000 there
are 152476 nodes and leaves. The roots were at level 2.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_block_rsv_add can return only ENOSPC since it's called with
NO_FLUSH modifier. This so simplify the logic in
btrfs_delayed_inode_reserve_metadata to exploit this invariant.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add assert and comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
It's only used for tracepoint to obtain the inode number, but we already
have the ino from btrfs_delayed_node::inode_id.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's no longer expected to call this function with an open transaction
so all the workarounds concerning this can be removed. In fact it'll
constitute a bug to call this function with a transaction already held
so WARN in this case.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Drop function declarations at the beginning of the file scrub.c. These
functions are defined before they are used in the same file and don't
need forward declaration.
No functional changes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_extent_readonly() checks if the block group is readonly, the bool
return type should be used.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_extent_readonly() is used by can_nocow_extent() in inode.c. So
move it from extent-tree.c to inode.c and declare it as static.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_inc_block_group_ro wants to ensure that the current transaction is
not running dirty block groups, if it is it waits and loops again.
That logic is currently implemented using a goto label. Actually using
a proper do {} while() construct doesn't hurt readability nor does it
introduce excessive nesting and makes the relevant code stand out by
being encompassed in the loop construct. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
No point in duplicating the functionality just use the generic helper
that has the same semantics.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is small error in comment about BTRFS_ORDERED_* flags, added in
commit 3c198fe064 ("btrfs: rework the order of
btrfs_ordered_extent::flags") but the fixup did not get merged in time.
The 4 types are for ordered extent itself, not for direct io.
Only 3 types support direct io, REGULAR/NOCOW/PREALLOC.
Fix the comment to reflect that.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Use the fileattr API to let the VFS handle locking, permission checking and
conversion.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.12-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fix from David Sterba:
"One more patch that we'd like to get to 5.12 before release.
It's changing where and how the superblock is stored in the zoned
mode. It is an on-disk format change but so far there are no
implications for users as the proper mkfs support hasn't been merged
and is waiting for the kernel side to settle.
Until now, the superblocks were derived from the zone index, but zone
size can differ per device. This is changed to be based on fixed
offset values, to make it independent of the device zone size.
The work on that got a bit delayed, we discussed the exact locations
to support potential device sizes and usecases. (Partially delayed
also due to my vacation.) Having that in the same release where the
zoned mode is declared usable is highly desired, there are userspace
projects that need to be updated to recognize the feature. Pushing
that to the next release would make things harder to test"
* tag 'for-5.12-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: move superblock logging zone location
Moves the location of the superblock logging zones. The new locations of
the logging zones are now determined based on fixed block addresses
instead of on fixed zone numbers.
The old placement method based on fixed zone numbers causes problems when
one needs to inspect a file system image without access to the drive zone
information. In such case, the super block locations cannot be reliably
determined as the zone size is unknown. By locating the superblock logging
zones using fixed addresses, we can scan a dumped file system image without
the zone information since a super block copy will always be present at or
after the fixed known locations.
Introduce the following three pairs of zones containing fixed offset
locations, regardless of the device zone size.
- primary superblock: offset 0B (and the following zone)
- first copy: offset 512G (and the following zone)
- Second copy: offset 4T (4096G, and the following zone)
If a logging zone is outside of the disk capacity, we do not record the
superblock copy.
The first copy position is much larger than for a non-zoned filesystem,
which is at 64M. This is to avoid overlapping with the log zones for
the primary superblock. This higher location is arbitrary but allows
supporting devices with very large zone sizes, plus some space around in
between.
Such large zone size is unrealistic and very unlikely to ever be seen in
real devices. Currently, SMR disks have a zone size of 256MB, and we are
expecting ZNS drives to be in the 1-4GB range, so this limit gives us
room to breathe. For now, we only allow zone sizes up to 8GB. The
maximum zone size that would still fit in the space is 256G.
The fixed location addresses are somewhat arbitrary, with the intent of
maintaining superblock reliability for smaller and larger devices, with
the preference for the latter. For this reason, there are two superblocks
under the first 1T. This should cover use cases for physical devices and
for emulated/device-mapper devices.
The superblock logging zones are reserved for superblock logging and
never used for data or metadata blocks. Note that we only reserve the
two zones per primary/copy actually used for superblock logging. We do
not reserve the ranges of zones possibly containing superblocks with the
largest supported zone size (0-16GB, 512G-528GB, 4096G-4112G).
The zones containing the fixed location offsets used to store
superblocks on a non-zoned volume are also reserved to avoid confusion.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
list_sort() internally casts the comparison function passed to it
to a different type with constant struct list_head pointers, and
uses this pointer to call the functions, which trips indirect call
Control-Flow Integrity (CFI) checking.
Instead of removing the consts, this change defines the
list_cmp_func_t type and changes the comparison function types of
all list_sort() callers to use const pointers, thus avoiding type
mismatches.
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-10-samitolvanen@google.com
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Merge tag 'for-5.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Fixes for issues that have some user visibility and are simple enough
for this time of development cycle:
- a few fixes for rescue= mount option, adding more checks for
missing trees
- fix sleeping in atomic context on qgroup deletion
- fix subvolume deletion on mount
- fix build with M= syntax
- fix checksum mismatch error message for direct io"
* tag 'for-5.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix check_data_csum() error message for direct I/O
btrfs: fix sleep while in non-sleep context during qgroup removal
btrfs: fix subvolume/snapshot deletion not triggered on mount
btrfs: fix build when using M=fs/btrfs
btrfs: do not initialize dev replace for bad dev root
btrfs: initialize device::fs_info always
btrfs: do not initialize dev stats if we have no dev_root
btrfs: zoned: remove outdated WARN_ON in direct IO
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Merge tag 'for-5.12-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"There are still regressions being found and fixed in the zoned mode
and subpage code, the rest are fixes for bugs reported by users.
Regressions:
- subpage block support:
- readahead works on the proper block size
- fix last page zeroing
- zoned mode:
- linked list corruption for tree log
Fixes:
- qgroup leak after falloc failure
- tree mod log and backref resolving:
- extent buffer cloning race when resolving backrefs
- pin deleted leaves with active tree mod log users
- drop debugging flag from slab cache"
* tag 'for-5.12-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: always pin deleted leaves when there are active tree mod log users
btrfs: fix race when cloning extent buffer during rewind of an old root
btrfs: fix slab cache flags for free space tree bitmap
btrfs: subpage: make readahead work properly
btrfs: subpage: fix wild pointer access during metadata read failure
btrfs: zoned: fix linked list corruption after log root tree allocation failure
btrfs: fix qgroup data rsv leak caused by falloc failure
btrfs: track qgroup released data in own variable in insert_prealloc_file_extent
btrfs: fix wrong offset to zero out range beyond i_size
Commit 1dae796aabf6 ("btrfs: inode: sink parameter start and len to
check_data_csum()") replaced the start parameter to check_data_csum()
with page_offset(), but page_offset() is not meaningful for direct I/O
pages. Bring back the start parameter.
Fixes: 265d4ac03f ("btrfs: sink parameter start and len to check_data_csum")
CC: stable@vger.kernel.org # 5.11+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During the mount procedure we are calling btrfs_orphan_cleanup() against
the root tree, which will find all orphans items in this tree. When an
orphan item corresponds to a deleted subvolume/snapshot (instead of an
inode space cache), it must not delete the orphan item, because that will
cause btrfs_find_orphan_roots() to not find the orphan item and therefore
not add the corresponding subvolume root to the list of dead roots, which
results in the subvolume's tree never being deleted by the cleanup thread.
The same applies to the remount from RO to RW path.
Fix this by making btrfs_find_orphan_roots() run before calling
btrfs_orphan_cleanup() against the root tree.
A test case for fstests will follow soon.
Reported-by: Robbie Ko <robbieko@synology.com>
Link: https://lore.kernel.org/linux-btrfs/b19f4310-35e0-606e-1eea-2dd84d28c5da@synology.com/
Fixes: 638331fa56 ("btrfs: fix transaction leak and crash after cleaning up orphans on RO mount")
CC: stable@vger.kernel.org # 5.11+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are people building the module with M= that's supposed to be used
for external modules. This got broken in e9aa7c285d ("btrfs: enable
W=1 checks for btrfs").
$ make M=fs/btrfs
scripts/Makefile.lib:10: *** Recursive variable 'KBUILD_CFLAGS' references itself (eventually). Stop.
make: *** [Makefile:1755: modules] Error 2
There's a difference compared to 'make fs/btrfs/btrfs.ko' which needs
to rebuild a few more things and also the dependency modules need to be
available. It could fail with eg.
WARNING: Symbol version dump "Module.symvers" is missing.
Modules may not have dependencies or modversions.
In some environments it's more convenient to rebuild just the btrfs
module by M= so let's make it work.
The problem is with recursive variable evaluation in += so the
conditional C options are stored in a temporary variable to avoid the
recursion.
Signed-off-by: David Sterba <dsterba@suse.com>
While helping Neal fix his broken file system I added a debug patch to
catch if we were calling btrfs_search_slot with a NULL root, and this
stack trace popped:
we tried to search with a NULL root
CPU: 0 PID: 1760 Comm: mount Not tainted 5.11.0-155.nealbtrfstest.1.fc34.x86_64 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/22/2020
Call Trace:
dump_stack+0x6b/0x83
btrfs_search_slot.cold+0x11/0x1b
? btrfs_init_dev_replace+0x36/0x450
btrfs_init_dev_replace+0x71/0x450
open_ctree+0x1054/0x1610
btrfs_mount_root.cold+0x13/0xfa
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
vfs_kern_mount.part.0+0x71/0xb0
btrfs_mount+0x131/0x3d0
? legacy_get_tree+0x27/0x40
? btrfs_show_options+0x640/0x640
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
path_mount+0x441/0xa80
__x64_sys_mount+0xf4/0x130
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f644730352e
Fix this by not starting the device replace stuff if we do not have a
NULL dev root.
Reported-by: Neal Gompa <ngompa13@gmail.com>
CC: stable@vger.kernel.org # 5.11+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Neal reported a panic trying to use -o rescue=all
BUG: kernel NULL pointer dereference, address: 0000000000000030
PGD 0 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 PID: 696 Comm: mount Tainted: G W 5.12.0-rc2+ #296
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
RIP: 0010:btrfs_device_init_dev_stats+0x1d/0x200
RSP: 0018:ffffafaec1483bb8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff9a5715bcb298 RCX: 0000000000000070
RDX: ffff9a5703248000 RSI: ffff9a57052ea150 RDI: ffff9a5715bca400
RBP: ffff9a57052ea150 R08: 0000000000000070 R09: ffff9a57052ea150
R10: 000130faf0741c10 R11: 0000000000000000 R12: ffff9a5703700000
R13: 0000000000000000 R14: ffff9a5715bcb278 R15: ffff9a57052ea150
FS: 00007f600d122c40(0000) GS:ffff9a577bc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 0000000112a46005 CR4: 0000000000370ef0
Call Trace:
? btrfs_init_dev_stats+0x1f/0xf0
? kmem_cache_alloc+0xef/0x1f0
btrfs_init_dev_stats+0x5f/0xf0
open_ctree+0x10cb/0x1720
btrfs_mount_root.cold+0x12/0xea
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
vfs_kern_mount.part.0+0x71/0xb0
btrfs_mount+0x10d/0x380
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
path_mount+0x433/0xa00
__x64_sys_mount+0xe3/0x120
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
This happens because when we call btrfs_init_dev_stats we do
device->fs_info->dev_root. However device->fs_info isn't initialized
because we were only calling btrfs_init_devices_late() if we properly
read the device root. However we don't actually need the device root to
init the devices, this function simply assigns the devices their
->fs_info pointer properly, so this needs to be done unconditionally
always so that we can properly dereference device->fs_info in rescue
cases.
Reported-by: Neal Gompa <ngompa13@gmail.com>
CC: stable@vger.kernel.org # 5.11+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_submit_direct() there's a WAN_ON_ONCE() that will trigger if
we're submitting a DIO write on a zoned filesystem but are not using
REQ_OP_ZONE_APPEND to submit the IO to the block device.
This is a left over from a previous version where btrfs_dio_iomap_begin()
didn't use btrfs_use_zone_append() to check for sequential write only
zones.
It is an oversight from the development phase. In v11 (I think) I've
added 08f455593f ("btrfs: zoned: cache if block group is on a
sequential zone") and forgot to remove the WARN_ON_ONCE() for
544d24f9de ("btrfs: zoned: enable zone append writing for direct IO").
When developing auto relocation I got hit by the WARN as a block groups
where relocated to conventional zone and the dio code calls
btrfs_use_zone_append() introduced by 08f455593f to check if it can
use zone append (a.k.a. if it's a sequential zone) or not and sets the
appropriate flags for iomap.
I've never hit it in testing before, as I was relying on emulation to
test the conventional zones code but this one case wasn't hit, because
on emulation fs_info->max_zone_append_size is 0 and the WARN doesn't
trigger either.
Fixes: 544d24f9de ("btrfs: zoned: enable zone append writing for direct IO")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When freeing a tree block we may end up adding its extent back to the
free space cache/tree, as long as there are no more references for it,
it was created in the current transaction and writeback for it never
happened. This is generally fine, however when we have tree mod log
operations it can result in inconsistent versions of a btree after
unwinding extent buffers with the recorded tree mod log operations.
This is because:
* We only log operations for nodes (adding and removing key/pointers),
for leaves we don't do anything;
* This means that we can log a MOD_LOG_KEY_REMOVE_WHILE_FREEING operation
for a node that points to a leaf that was deleted;
* Before we apply the logged operation to unwind a node, we can have
that leaf's extent allocated again, either as a node or as a leaf, and
possibly for another btree. This is possible if the leaf was created in
the current transaction and writeback for it never started, in which
case btrfs_free_tree_block() returns its extent back to the free space
cache/tree;
* Then, before applying the tree mod log operation, some task allocates
the metadata extent just freed before, and uses it either as a leaf or
as a node for some btree (can be the same or another one, it does not
matter);
* After applying the MOD_LOG_KEY_REMOVE_WHILE_FREEING operation we now
get the target node with an item pointing to the metadata extent that
now has content different from what it had before the leaf was deleted.
It might now belong to a different btree and be a node and not a leaf
anymore.
As a consequence, the results of searches after the unwinding can be
unpredictable and produce unexpected results.
So make sure we pin extent buffers corresponding to leaves when there
are tree mod log users.
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While resolving backreferences, as part of a logical ino ioctl call or
fiemap, we can end up hitting a BUG_ON() when replaying tree mod log
operations of a root, triggering a stack trace like the following:
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.c:1210!
invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 PID: 19054 Comm: crawl_335 Tainted: G W 5.11.0-2d11c0084b02-misc-next+ #89
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:__tree_mod_log_rewind+0x3b1/0x3c0
Code: 05 48 8d 74 10 (...)
RSP: 0018:ffffc90001eb70b8 EFLAGS: 00010297
RAX: 0000000000000000 RBX: ffff88812344e400 RCX: ffffffffb28933b6
RDX: 0000000000000007 RSI: dffffc0000000000 RDI: ffff88812344e42c
RBP: ffffc90001eb7108 R08: 1ffff11020b60a20 R09: ffffed1020b60a20
R10: ffff888105b050f9 R11: ffffed1020b60a1f R12: 00000000000000ee
R13: ffff8880195520c0 R14: ffff8881bc958500 R15: ffff88812344e42c
FS: 00007fd1955e8700(0000) GS:ffff8881f5600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efdb7928718 CR3: 000000010103a006 CR4: 0000000000170ee0
Call Trace:
btrfs_search_old_slot+0x265/0x10d0
? lock_acquired+0xbb/0x600
? btrfs_search_slot+0x1090/0x1090
? free_extent_buffer.part.61+0xd7/0x140
? free_extent_buffer+0x13/0x20
resolve_indirect_refs+0x3e9/0xfc0
? lock_downgrade+0x3d0/0x3d0
? __kasan_check_read+0x11/0x20
? add_prelim_ref.part.11+0x150/0x150
? lock_downgrade+0x3d0/0x3d0
? __kasan_check_read+0x11/0x20
? lock_acquired+0xbb/0x600
? __kasan_check_write+0x14/0x20
? do_raw_spin_unlock+0xa8/0x140
? rb_insert_color+0x30/0x360
? prelim_ref_insert+0x12d/0x430
find_parent_nodes+0x5c3/0x1830
? resolve_indirect_refs+0xfc0/0xfc0
? lock_release+0xc8/0x620
? fs_reclaim_acquire+0x67/0xf0
? lock_acquire+0xc7/0x510
? lock_downgrade+0x3d0/0x3d0
? lockdep_hardirqs_on_prepare+0x160/0x210
? lock_release+0xc8/0x620
? fs_reclaim_acquire+0x67/0xf0
? lock_acquire+0xc7/0x510
? poison_range+0x38/0x40
? unpoison_range+0x14/0x40
? trace_hardirqs_on+0x55/0x120
btrfs_find_all_roots_safe+0x142/0x1e0
? find_parent_nodes+0x1830/0x1830
? btrfs_inode_flags_to_xflags+0x50/0x50
iterate_extent_inodes+0x20e/0x580
? tree_backref_for_extent+0x230/0x230
? lock_downgrade+0x3d0/0x3d0
? read_extent_buffer+0xdd/0x110
? lock_downgrade+0x3d0/0x3d0
? __kasan_check_read+0x11/0x20
? lock_acquired+0xbb/0x600
? __kasan_check_write+0x14/0x20
? _raw_spin_unlock+0x22/0x30
? __kasan_check_write+0x14/0x20
iterate_inodes_from_logical+0x129/0x170
? iterate_inodes_from_logical+0x129/0x170
? btrfs_inode_flags_to_xflags+0x50/0x50
? iterate_extent_inodes+0x580/0x580
? __vmalloc_node+0x92/0xb0
? init_data_container+0x34/0xb0
? init_data_container+0x34/0xb0
? kvmalloc_node+0x60/0x80
btrfs_ioctl_logical_to_ino+0x158/0x230
btrfs_ioctl+0x205e/0x4040
? __might_sleep+0x71/0xe0
? btrfs_ioctl_get_supported_features+0x30/0x30
? getrusage+0x4b6/0x9c0
? __kasan_check_read+0x11/0x20
? lock_release+0xc8/0x620
? __might_fault+0x64/0xd0
? lock_acquire+0xc7/0x510
? lock_downgrade+0x3d0/0x3d0
? lockdep_hardirqs_on_prepare+0x210/0x210
? lockdep_hardirqs_on_prepare+0x210/0x210
? __kasan_check_read+0x11/0x20
? do_vfs_ioctl+0xfc/0x9d0
? ioctl_file_clone+0xe0/0xe0
? lock_downgrade+0x3d0/0x3d0
? lockdep_hardirqs_on_prepare+0x210/0x210
? __kasan_check_read+0x11/0x20
? lock_release+0xc8/0x620
? __task_pid_nr_ns+0xd3/0x250
? lock_acquire+0xc7/0x510
? __fget_files+0x160/0x230
? __fget_light+0xf2/0x110
__x64_sys_ioctl+0xc3/0x100
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fd1976e2427
Code: 00 00 90 48 8b 05 (...)
RSP: 002b:00007fd1955e5cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd1955e5f40 RCX: 00007fd1976e2427
RDX: 00007fd1955e5f48 RSI: 00000000c038943b RDI: 0000000000000004
RBP: 0000000001000000 R08: 0000000000000000 R09: 00007fd1955e6120
R10: 0000557835366b00 R11: 0000000000000246 R12: 0000000000000004
R13: 00007fd1955e5f48 R14: 00007fd1955e5f40 R15: 00007fd1955e5ef8
Modules linked in:
---[ end trace ec8931a1c36e57be ]---
(gdb) l *(__tree_mod_log_rewind+0x3b1)
0xffffffff81893521 is in __tree_mod_log_rewind (fs/btrfs/ctree.c:1210).
1205 * the modification. as we're going backwards, we do the
1206 * opposite of each operation here.
1207 */
1208 switch (tm->op) {
1209 case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
1210 BUG_ON(tm->slot < n);
1211 fallthrough;
1212 case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
1213 case MOD_LOG_KEY_REMOVE:
1214 btrfs_set_node_key(eb, &tm->key, tm->slot);
Here's what happens to hit that BUG_ON():
1) We have one tree mod log user (through fiemap or the logical ino ioctl),
with a sequence number of 1, so we have fs_info->tree_mod_seq == 1;
2) Another task is at ctree.c:balance_level() and we have eb X currently as
the root of the tree, and we promote its single child, eb Y, as the new
root.
Then, at ctree.c:balance_level(), we call:
tree_mod_log_insert_root(eb X, eb Y, 1);
3) At tree_mod_log_insert_root() we create tree mod log elements for each
slot of eb X, of operation type MOD_LOG_KEY_REMOVE_WHILE_FREEING each
with a ->logical pointing to ebX->start. These are placed in an array
named tm_list.
Lets assume there are N elements (N pointers in eb X);
4) Then, still at tree_mod_log_insert_root(), we create a tree mod log
element of operation type MOD_LOG_ROOT_REPLACE, ->logical set to
ebY->start, ->old_root.logical set to ebX->start, ->old_root.level set
to the level of eb X and ->generation set to the generation of eb X;
5) Then tree_mod_log_insert_root() calls tree_mod_log_free_eb() with
tm_list as argument. After that, tree_mod_log_free_eb() calls
__tree_mod_log_insert() for each member of tm_list in reverse order,
from highest slot in eb X, slot N - 1, to slot 0 of eb X;
6) __tree_mod_log_insert() sets the sequence number of each given tree mod
log operation - it increments fs_info->tree_mod_seq and sets
fs_info->tree_mod_seq as the sequence number of the given tree mod log
operation.
This means that for the tm_list created at tree_mod_log_insert_root(),
the element corresponding to slot 0 of eb X has the highest sequence
number (1 + N), and the element corresponding to the last slot has the
lowest sequence number (2);
7) Then, after inserting tm_list's elements into the tree mod log rbtree,
the MOD_LOG_ROOT_REPLACE element is inserted, which gets the highest
sequence number, which is N + 2;
8) Back to ctree.c:balance_level(), we free eb X by calling
btrfs_free_tree_block() on it. Because eb X was created in the current
transaction, has no other references and writeback did not happen for
it, we add it back to the free space cache/tree;
9) Later some other task T allocates the metadata extent from eb X, since
it is marked as free space in the space cache/tree, and uses it as a
node for some other btree;
10) The tree mod log user task calls btrfs_search_old_slot(), which calls
get_old_root(), and finally that calls __tree_mod_log_oldest_root()
with time_seq == 1 and eb_root == eb Y;
11) First iteration of the while loop finds the tree mod log element with
sequence number N + 2, for the logical address of eb Y and of type
MOD_LOG_ROOT_REPLACE;
12) Because the operation type is MOD_LOG_ROOT_REPLACE, we don't break out
of the loop, and set root_logical to point to tm->old_root.logical
which corresponds to the logical address of eb X;
13) On the next iteration of the while loop, the call to
tree_mod_log_search_oldest() returns the smallest tree mod log element
for the logical address of eb X, which has a sequence number of 2, an
operation type of MOD_LOG_KEY_REMOVE_WHILE_FREEING and corresponds to
the old slot N - 1 of eb X (eb X had N items in it before being freed);
14) We then break out of the while loop and return the tree mod log operation
of type MOD_LOG_ROOT_REPLACE (eb Y), and not the one for slot N - 1 of
eb X, to get_old_root();
15) At get_old_root(), we process the MOD_LOG_ROOT_REPLACE operation
and set "logical" to the logical address of eb X, which was the old
root. We then call tree_mod_log_search() passing it the logical
address of eb X and time_seq == 1;
16) Then before calling tree_mod_log_search(), task T adds a key to eb X,
which results in adding a tree mod log operation of type
MOD_LOG_KEY_ADD to the tree mod log - this is done at
ctree.c:insert_ptr() - but after adding the tree mod log operation
and before updating the number of items in eb X from 0 to 1...
17) The task at get_old_root() calls tree_mod_log_search() and gets the
tree mod log operation of type MOD_LOG_KEY_ADD just added by task T.
Then it enters the following if branch:
if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
(...)
} (...)
Calls read_tree_block() for eb X, which gets a reference on eb X but
does not lock it - task T has it locked.
Then it clones eb X while it has nritems set to 0 in its header, before
task T sets nritems to 1 in eb X's header. From hereupon we use the
clone of eb X which no other task has access to;
18) Then we call __tree_mod_log_rewind(), passing it the MOD_LOG_KEY_ADD
mod log operation we just got from tree_mod_log_search() in the
previous step and the cloned version of eb X;
19) At __tree_mod_log_rewind(), we set the local variable "n" to the number
of items set in eb X's clone, which is 0. Then we enter the while loop,
and in its first iteration we process the MOD_LOG_KEY_ADD operation,
which just decrements "n" from 0 to (u32)-1, since "n" is declared with
a type of u32. At the end of this iteration we call rb_next() to find the
next tree mod log operation for eb X, that gives us the mod log operation
of type MOD_LOG_KEY_REMOVE_WHILE_FREEING, for slot 0, with a sequence
number of N + 1 (steps 3 to 6);
20) Then we go back to the top of the while loop and trigger the following
BUG_ON():
(...)
switch (tm->op) {
case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
BUG_ON(tm->slot < n);
fallthrough;
(...)
Because "n" has a value of (u32)-1 (4294967295) and tm->slot is 0.
Fix this by taking a read lock on the extent buffer before cloning it at
ctree.c:get_old_root(). This should be done regardless of the extent
buffer having been freed and reused, as a concurrent task might be
modifying it (while holding a write lock on it).
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Link: https://lore.kernel.org/linux-btrfs/20210227155037.GN28049@hungrycats.org/
Fixes: 834328a849 ("Btrfs: tree mod log's old roots could still be part of the tree")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The free space tree bitmap slab cache is created with SLAB_RED_ZONE but
that's a debugging flag and not always enabled. Also the other slabs are
created with at least SLAB_MEM_SPREAD that we want as well to average
the memory placement cost.
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Fixes: 3acd48507d ("btrfs: fix allocation of free space cache v1 bitmap pages")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: David Sterba <dsterba@suse.com>
In readahead infrastructure, we are using a lot of hard coded PAGE_SHIFT
while we're not doing anything specific to PAGE_SIZE.
One of the most affected part is the radix tree operation of
btrfs_fs_info::reada_tree.
If using PAGE_SHIFT, subpage metadata readahead is broken and does no
help reading metadata ahead.
Fix the problem by using btrfs_fs_info::sectorsize_bits so that
readahead could work for subpage.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running fstests for btrfs subpage read-write test, it has a very
high chance to crash at generic/475 with the following stack:
BTRFS warning (device dm-8): direct IO failed ino 510 rw 1,34817 sector 0xcdf0 len 94208 err no 10
Unable to handle kernel paging request at virtual address ffff80001157e7c0
CPU: 2 PID: 687125 Comm: kworker/u12:4 Tainted: G WC 5.12.0-rc2-custom+ #5
Hardware name: Khadas VIM3 (DT)
Workqueue: btrfs-endio-meta btrfs_work_helper [btrfs]
pc : queued_spin_lock_slowpath+0x1a0/0x390
lr : do_raw_spin_lock+0xc4/0x11c
Call trace:
queued_spin_lock_slowpath+0x1a0/0x390
_raw_spin_lock+0x68/0x84
btree_readahead_hook+0x38/0xc0 [btrfs]
end_bio_extent_readpage+0x504/0x5f4 [btrfs]
bio_endio+0x170/0x1a4
end_workqueue_fn+0x3c/0x60 [btrfs]
btrfs_work_helper+0x1b0/0x1b4 [btrfs]
process_one_work+0x22c/0x430
worker_thread+0x70/0x3a0
kthread+0x13c/0x140
ret_from_fork+0x10/0x30
Code: 910020e0 8b0200c2 f861d884 aa0203e1 (f8246827)
[CAUSE]
In end_bio_extent_readpage(), if we hit an error during read, we will
handle the error differently for data and metadata.
For data we queue a repair, while for metadata, we record the error and
let the caller choose what to do.
But the code is still using page->private to grab extent buffer, which
no longer points to extent buffer for subpage metadata pages.
Thus this wild pointer access leads to above crash.
[FIX]
Introduce a helper, find_extent_buffer_readpage(), to grab extent
buffer.
The difference against find_extent_buffer_nospinlock() is:
- Also handles regular sectorsize == PAGE_SIZE case
- No extent buffer refs increase/decrease
As extent buffer under IO must have non-zero refs, so this is safe
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When using a zoned filesystem, while syncing the log, if we fail to
allocate the root node for the log root tree, we are not removing the
log context we allocated on stack from the list of log contexts of the
log root tree. This means after the return from btrfs_sync_log() we get
a corrupted linked list.
Fix this by allocating the node before adding our stack allocated context
to the list of log contexts of the log root tree.
Fixes: 3ddebf27fc ("btrfs: zoned: reorder log node allocation on zoned filesystem")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running fsstress with only falloc workload, and a very low qgroup
limit set, we can get qgroup data rsv leak at unmount time.
BTRFS warning (device dm-0): qgroup 0/5 has unreleased space, type 0 rsv 20480
BTRFS error (device dm-0): qgroup reserved space leaked
The minimal reproducer looks like:
#!/bin/bash
dev=/dev/test/test
mnt="/mnt/btrfs"
fsstress=~/xfstests-dev/ltp/fsstress
runtime=8
workload()
{
umount $dev &> /dev/null
umount $mnt &> /dev/null
mkfs.btrfs -f $dev > /dev/null
mount $dev $mnt
btrfs quota en $mnt
btrfs quota rescan -w $mnt
btrfs qgroup limit 16m 0/5 $mnt
$fsstress -w -z -f creat=10 -f fallocate=10 -p 2 -n 100 \
-d $mnt -v > /tmp/fsstress
umount $mnt
if dmesg | grep leak ; then
echo "!!! FAILED !!!"
exit 1
fi
}
for (( i=0; i < $runtime; i++)); do
echo "=== $i/$runtime==="
workload
done
Normally it would fail before round 4.
[CAUSE]
In function insert_prealloc_file_extent(), we first call
btrfs_qgroup_release_data() to know how many bytes are reserved for
qgroup data rsv.
Then use that @qgroup_released number to continue our work.
But after we call btrfs_qgroup_release_data(), we should either queue
@qgroup_released to delayed ref or free them manually in error path.
Unfortunately, we lack the error handling to free the released bytes,
leaking qgroup data rsv.
All the error handling function outside won't help at all, as we have
released the range, meaning in inode io tree, the EXTENT_QGROUP_RESERVED
bit is already cleared, thus all btrfs_qgroup_free_data() call won't
free any data rsv.
[FIX]
Add free_qgroup tag to manually free the released qgroup data rsv.
Reported-by: Nikolay Borisov <nborisov@suse.com>
Reported-by: David Sterba <dsterba@suse.cz>
Fixes: 9729f10a60 ("btrfs: inode: move qgroup reserved space release to the callers of insert_reserved_file_extent()")
CC: stable@vger.kernel.org # 5.10+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a piece of weird code in insert_prealloc_file_extent(), which
looks like:
ret = btrfs_qgroup_release_data(inode, file_offset, len);
if (ret < 0)
return ERR_PTR(ret);
if (trans) {
ret = insert_reserved_file_extent(trans, inode,
file_offset, &stack_fi,
true, ret);
...
}
extent_info.is_new_extent = true;
extent_info.qgroup_reserved = ret;
...
Note how the variable @ret is abused here, and if anyone is adding code
just after btrfs_qgroup_release_data() call, it's super easy to
overwrite the @ret and cause tons of qgroup related bugs.
Fix such abuse by introducing new variable @qgroup_released, so that we
won't reuse the existing variable @ret.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
The test generic/091 fails , with the following output:
fsx -N 10000 -o 128000 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z -W
mapped writes DISABLED
Seed set to 1
main: filesystem does not support fallocate mode FALLOC_FL_COLLAPSE_RANGE, disabling!
main: filesystem does not support fallocate mode FALLOC_FL_INSERT_RANGE, disabling!
skipping zero size read
truncating to largest ever: 0xe400
copying to largest ever: 0x1f400
cloning to largest ever: 0x70000
cloning to largest ever: 0x77000
fallocating to largest ever: 0x7a120
Mapped Read: non-zero data past EOF (0x3a7ff) page offset 0x800 is 0xf2e1 <<<
...
[CAUSE]
In commit c28ea613fa ("btrfs: subpage: fix the false data csum mismatch error")
end_bio_extent_readpage() changes to only zero the range inside the bvec
for incoming subpage support.
But that commit is using incorrect offset to calculate the start.
For subpage, we can have a case that the whole bvec is beyond isize,
thus we need to calculate the correct offset.
But the offending commit is using @end (bvec end), other than @start
(bvec start) to calculate the start offset.
This means, we only zero the last byte of the bvec, not from the isize.
This stupid bug makes the range beyond isize is not properly zeroed, and
failed above test.
[FIX]
Use correct @start to calculate the range start.
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: c28ea613fa ("btrfs: subpage: fix the false data csum mismatch error")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'block-5.12-2021-03-12-v2' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"Mostly just random fixes all over the map.
The only odd-one-out change is finally getting the rename of
BIO_MAX_PAGES to BIO_MAX_VECS done. This should've been done with the
multipage bvec change, but it's been left.
Do it now to avoid hassles around changes piling up for the next merge
window.
Summary:
- NVMe pull request:
- one more quirk (Dmitry Monakhov)
- fix max_zone_append_sectors initialization (Chaitanya Kulkarni)
- nvme-fc reset/create race fix (James Smart)
- fix status code on aborts/resets (Hannes Reinecke)
- fix the CSS check for ZNS namespaces (Chaitanya Kulkarni)
- fix a use after free in a debug printk in nvme-rdma (Lv Yunlong)
- Follow-up NVMe error fix for NULL 'id' (Christoph)
- Fixup for the bd_size_lock being IRQ safe, now that the offending
driver has been dropped (Damien).
- rsxx probe failure error return (Jia-Ju)
- umem probe failure error return (Wei)
- s390/dasd unbind fixes (Stefan)
- blk-cgroup stats summing fix (Xunlei)
- zone reset handling fix (Damien)
- Rename BIO_MAX_PAGES to BIO_MAX_VECS (Christoph)
- Suppress uevent trigger for hidden devices (Daniel)
- Fix handling of discard on busy device (Jan)
- Fix stale cache issue with zone reset (Shin'ichiro)"
* tag 'block-5.12-2021-03-12-v2' of git://git.kernel.dk/linux-block:
nvme: fix the nsid value to print in nvme_validate_or_alloc_ns
block: Discard page cache of zone reset target range
block: Suppress uevent for hidden device when removed
block: rename BIO_MAX_PAGES to BIO_MAX_VECS
nvme-pci: add the DISABLE_WRITE_ZEROES quirk for a Samsung PM1725a
nvme-rdma: Fix a use after free in nvmet_rdma_write_data_done
nvme-core: check ctrl css before setting up zns
nvme-fc: fix racing controller reset and create association
nvme-fc: return NVME_SC_HOST_ABORTED_CMD when a command has been aborted
nvme-fc: set NVME_REQ_CANCELLED in nvme_fc_terminate_exchange()
nvme: add NVME_REQ_CANCELLED flag in nvme_cancel_request()
nvme: simplify error logic in nvme_validate_ns()
nvme: set max_zone_append_sectors nvme_revalidate_zones
block: rsxx: fix error return code of rsxx_pci_probe()
block: Fix REQ_OP_ZONE_RESET_ALL handling
umem: fix error return code in mm_pci_probe()
blk-cgroup: Fix the recursive blkg rwstat
s390/dasd: fix hanging IO request during DASD driver unbind
s390/dasd: fix hanging DASD driver unbind
block: Try to handle busy underlying device on discard
Ever since the addition of multipage bio_vecs BIO_MAX_PAGES has been
horribly confusingly misnamed. Rename it to BIO_MAX_VECS to stop
confusing users of the bio API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210311110137.1132391-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"More regression fixes and stabilization.
Regressions:
- zoned mode
- count zone sizes in wider int types
- fix space accounting for read-only block groups
- subpage: fix page tail zeroing
Fixes:
- fix spurious warning when remounting with free space tree
- fix warning when creating a directory with smack enabled
- ioctl checks for qgroup inheritance when creating a snapshot
- qgroup
- fix missing unlock on error path in zero range
- fix amount of released reservation on error
- fix flushing from unsafe context with open transaction,
potentially deadlocking
- minor build warning fixes"
* tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: do not account freed region of read-only block group as zone_unusable
btrfs: zoned: use sector_t for zone sectors
btrfs: subpage: fix the false data csum mismatch error
btrfs: fix warning when creating a directory with smack enabled
btrfs: don't flush from btrfs_delayed_inode_reserve_metadata
btrfs: export and rename qgroup_reserve_meta
btrfs: free correct amount of space in btrfs_delayed_inode_reserve_metadata
btrfs: fix spurious free_space_tree remount warning
btrfs: validate qgroup inherit for SNAP_CREATE_V2 ioctl
btrfs: unlock extents in btrfs_zero_range in case of quota reservation errors
btrfs: ref-verify: use 'inline void' keyword ordering
We migrate zone unusable bytes to read-only bytes when a block group is
set to read-only, and account all the free region as bytes_readonly.
Thus, we should not increase block_group->zone_unusable when the block
group is read-only.
Fixes: 169e0da91a ("btrfs: zoned: track unusable bytes for zones")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We need to use sector_t for zone_sectors, or it would set the zone size
to zero when the size >= 4GB (= 2^24 sectors) by shifting the
zone_sectors value by SECTOR_SHIFT. We're assuming zones sizes up to
8GiB.
Fixes: 5b31646898 ("btrfs: get zone information of zoned block devices")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running fstresss, we can hit strange data csum mismatch where the
on-disk data is in fact correct (passes scrub).
With some extra debug info added, we have the following traces:
0482us: btrfs_do_readpage: root=5 ino=284 offset=393216, submit force=0 pgoff=0 iosize=8192
0494us: btrfs_do_readpage: root=5 ino=284 offset=401408, submit force=0 pgoff=8192 iosize=4096
0498us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=393216 len=8192
0591us: btrfs_do_readpage: root=5 ino=284 offset=405504, submit force=0 pgoff=12288 iosize=36864
0594us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=401408 len=4096
0863us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=405504 len=36864
0933us: btrfs_verify_data_csum: root=5 ino=284 offset=393216 len=8192
0967us: btrfs_do_readpage: root=5 ino=284 offset=442368, skip beyond isize pgoff=49152 iosize=16384
1047us: btrfs_verify_data_csum: root=5 ino=284 offset=401408 len=4096
1163us: btrfs_verify_data_csum: root=5 ino=284 offset=405504 len=36864
1290us: check_data_csum: !!! root=5 ino=284 offset=438272 pg_off=45056 !!!
7387us: end_bio_extent_readpage: root=5 ino=284 before pending_read_bios=0
[CAUSE]
Normally we expect all submitted bio reads to only touch the range we
specified, and under subpage context, it means we should only touch the
range specified in each bvec.
But in data read path, inside end_bio_extent_readpage(), we have page
zeroing which only takes regular page size into consideration.
This means for subpage if we have an inode whose content looks like below:
0 16K 32K 48K 64K
|///////| |///////| |
|//| = data needs to be read from disk
| | = hole
And i_size is 64K initially.
Then the following race can happen:
T1 | T2
--------------------------------+--------------------------------
btrfs_do_readpage() |
|- isize = 64K; |
| At this time, the isize is |
| 64K |
| |
|- submit_extent_page() |
| submit previous assembled bio|
| assemble bio for [0, 16K) |
| |
|- submit_extent_page() |
submit read bio for [0, 16K) |
assemble read bio for |
[32K, 48K) |
|
| btrfs_setsize()
| |- i_size_write(, 16K);
| Now i_size is only 16K
end_io() for [0K, 16K) |
|- end_bio_extent_readpage() |
|- btrfs_verify_data_csum() |
| No csum error |
|- i_size = 16K; |
|- zero_user_segment(16K, |
PAGE_SIZE); |
!!! We zeroed range |
!!! [32K, 48K) |
| end_io for [32K, 48K)
| |- end_bio_extent_readpage()
| |- btrfs_verify_data_csum()
| ! CSUM MISMATCH !
| ! As the range is zeroed now !
[FIX]
To fix the problem, make end_bio_extent_readpage() to only zero the
range of bvec.
The bug only affects subpage read-write support, as for full read-only
mount we can't change i_size thus won't hit the race condition.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we have smack enabled, during the creation of a directory smack may
attempt to add a "smack transmute" xattr on the inode, which results in
the following warning and trace:
WARNING: CPU: 3 PID: 2548 at fs/btrfs/transaction.c:537 start_transaction+0x489/0x4f0
Modules linked in: nft_objref nf_conntrack_netbios_ns (...)
CPU: 3 PID: 2548 Comm: mkdir Not tainted 5.9.0-rc2smack+ #81
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
RIP: 0010:start_transaction+0x489/0x4f0
Code: e9 be fc ff ff (...)
RSP: 0018:ffffc90001887d10 EFLAGS: 00010202
RAX: ffff88816f1e0000 RBX: 0000000000000201 RCX: 0000000000000003
RDX: 0000000000000201 RSI: 0000000000000002 RDI: ffff888177849000
RBP: ffff888177849000 R08: 0000000000000001 R09: 0000000000000004
R10: ffffffff825e8f7a R11: 0000000000000003 R12: ffffffffffffffe2
R13: 0000000000000000 R14: ffff88803d884270 R15: ffff8881680d8000
FS: 00007f67317b8440(0000) GS:ffff88817bcc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f67247a22a8 CR3: 000000004bfbc002 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
? slab_free_freelist_hook+0xea/0x1b0
? trace_hardirqs_on+0x1c/0xe0
btrfs_setxattr_trans+0x3c/0xf0
__vfs_setxattr+0x63/0x80
smack_d_instantiate+0x2d3/0x360
security_d_instantiate+0x29/0x40
d_instantiate_new+0x38/0x90
btrfs_mkdir+0x1cf/0x1e0
vfs_mkdir+0x14f/0x200
do_mkdirat+0x6d/0x110
do_syscall_64+0x2d/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f673196ae6b
Code: 8b 05 11 (...)
RSP: 002b:00007ffc3c679b18 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00000000000001ff RCX: 00007f673196ae6b
RDX: 0000000000000000 RSI: 00000000000001ff RDI: 00007ffc3c67a30d
RBP: 00007ffc3c67a30d R08: 00000000000001ff R09: 0000000000000000
R10: 000055d3e39fe930 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc3c679cd8 R14: 00007ffc3c67a30d R15: 00007ffc3c679ce0
irq event stamp: 11029
hardirqs last enabled at (11037): [<ffffffff81153fe6>] console_unlock+0x486/0x670
hardirqs last disabled at (11044): [<ffffffff81153c01>] console_unlock+0xa1/0x670
softirqs last enabled at (8864): [<ffffffff81e0102f>] asm_call_on_stack+0xf/0x20
softirqs last disabled at (8851): [<ffffffff81e0102f>] asm_call_on_stack+0xf/0x20
This happens because at btrfs_mkdir() we call d_instantiate_new() while
holding a transaction handle, which results in the following call chain:
btrfs_mkdir()
trans = btrfs_start_transaction(root, 5);
d_instantiate_new()
smack_d_instantiate()
__vfs_setxattr()
btrfs_setxattr_trans()
btrfs_start_transaction()
start_transaction()
WARN_ON()
--> a tansaction start has TRANS_EXTWRITERS
set in its type
h->orig_rsv = h->block_rsv
h->block_rsv = NULL
btrfs_end_transaction(trans)
Besides the warning triggered at start_transaction, we set the handle's
block_rsv to NULL which may cause some surprises later on.
So fix this by making btrfs_setxattr_trans() not start a transaction when
we already have a handle on one, stored in current->journal_info, and use
that handle. We are good to use the handle because at btrfs_mkdir() we did
reserve space for the xattr and the inode item.
Reported-by: Casey Schaufler <casey@schaufler-ca.com>
CC: stable@vger.kernel.org # 5.4+
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>
Link: https://lore.kernel.org/linux-btrfs/434d856f-bd7b-4889-a6ec-e81aaebfa735@schaufler-ca.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Calling btrfs_qgroup_reserve_meta_prealloc from
btrfs_delayed_inode_reserve_metadata can result in flushing delalloc
while holding a transaction and delayed node locks. This is deadlock
prone. In the past multiple commits:
* ae5e070eac ("btrfs: qgroup: don't try to wait flushing if we're
already holding a transaction")
* 6f23277a49 ("btrfs: qgroup: don't commit transaction when we already
hold the handle")
Tried to solve various aspects of this but this was always a
whack-a-mole game. Unfortunately those 2 fixes don't solve a deadlock
scenario involving btrfs_delayed_node::mutex. Namely, one thread
can call btrfs_dirty_inode as a result of reading a file and modifying
its atime:
PID: 6963 TASK: ffff8c7f3f94c000 CPU: 2 COMMAND: "test"
#0 __schedule at ffffffffa529e07d
#1 schedule at ffffffffa529e4ff
#2 schedule_timeout at ffffffffa52a1bdd
#3 wait_for_completion at ffffffffa529eeea <-- sleeps with delayed node mutex held
#4 start_delalloc_inodes at ffffffffc0380db5
#5 btrfs_start_delalloc_snapshot at ffffffffc0393836
#6 try_flush_qgroup at ffffffffc03f04b2
#7 __btrfs_qgroup_reserve_meta at ffffffffc03f5bb6 <-- tries to reserve space and starts delalloc inodes.
#8 btrfs_delayed_update_inode at ffffffffc03e31aa <-- acquires delayed node mutex
#9 btrfs_update_inode at ffffffffc0385ba8
#10 btrfs_dirty_inode at ffffffffc038627b <-- TRANSACTIION OPENED
#11 touch_atime at ffffffffa4cf0000
#12 generic_file_read_iter at ffffffffa4c1f123
#13 new_sync_read at ffffffffa4ccdc8a
#14 vfs_read at ffffffffa4cd0849
#15 ksys_read at ffffffffa4cd0bd1
#16 do_syscall_64 at ffffffffa4a052eb
#17 entry_SYSCALL_64_after_hwframe at ffffffffa540008c
This will cause an asynchronous work to flush the delalloc inodes to
happen which can try to acquire the same delayed_node mutex:
PID: 455 TASK: ffff8c8085fa4000 CPU: 5 COMMAND: "kworker/u16:30"
#0 __schedule at ffffffffa529e07d
#1 schedule at ffffffffa529e4ff
#2 schedule_preempt_disabled at ffffffffa529e80a
#3 __mutex_lock at ffffffffa529fdcb <-- goes to sleep, never wakes up.
#4 btrfs_delayed_update_inode at ffffffffc03e3143 <-- tries to acquire the mutex
#5 btrfs_update_inode at ffffffffc0385ba8 <-- this is the same inode that pid 6963 is holding
#6 cow_file_range_inline.constprop.78 at ffffffffc0386be7
#7 cow_file_range at ffffffffc03879c1
#8 btrfs_run_delalloc_range at ffffffffc038894c
#9 writepage_delalloc at ffffffffc03a3c8f
#10 __extent_writepage at ffffffffc03a4c01
#11 extent_write_cache_pages at ffffffffc03a500b
#12 extent_writepages at ffffffffc03a6de2
#13 do_writepages at ffffffffa4c277eb
#14 __filemap_fdatawrite_range at ffffffffa4c1e5bb
#15 btrfs_run_delalloc_work at ffffffffc0380987 <-- starts running delayed nodes
#16 normal_work_helper at ffffffffc03b706c
#17 process_one_work at ffffffffa4aba4e4
#18 worker_thread at ffffffffa4aba6fd
#19 kthread at ffffffffa4ac0a3d
#20 ret_from_fork at ffffffffa54001ff
To fully address those cases the complete fix is to never issue any
flushing while holding the transaction or the delayed node lock. This
patch achieves it by calling qgroup_reserve_meta directly which will
either succeed without flushing or will fail and return -EDQUOT. In the
latter case that return value is going to be propagated to
btrfs_dirty_inode which will fallback to start a new transaction. That's
fine as the majority of time we expect the inode will have
BTRFS_DELAYED_NODE_INODE_DIRTY flag set which will result in directly
copying the in-memory state.
Fixes: c53e965360 ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Following commit f218ea6c47 ("btrfs: delayed-inode: Remove wrong
qgroup meta reservation calls") this function now reserves num_bytes,
rather than the fixed amount of nodesize. As such this requires the
same amount to be freed in case of failure. Fix this by adjusting
the amount we are freeing.
Fixes: f218ea6c47 ("btrfs: delayed-inode: Remove wrong qgroup meta reservation calls")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The intended logic of the check is to catch cases where the desired
free_space_tree setting doesn't match the mounted setting, and the
remount is anything but ro->rw. However, it makes the mistake of
checking equality on a masked integer (btrfs_test_opt) against a boolean
(btrfs_fs_compat_ro).
If you run the reproducer:
$ mount -o space_cache=v2 dev mnt
$ mount -o remount,ro mnt
you would expect no warning, because the remount is not attempting to
change the free space tree setting, but we do see the warning.
To fix this, add explicit bool type casts to the condition.
I tested a variety of transitions:
sudo mount -o space_cache=v2 /dev/vg0/lv0 mnt/lol
(fst enabled)
mount -o remount,ro mnt/lol
(no warning, no fst change)
sudo mount -o remount,rw,space_cache=v1,clear_cache
(no warning, ro->rw)
sudo mount -o remount,rw,space_cache=v2 mnt
(warning, rw->rw with change)
sudo mount -o remount,ro mnt
(no warning, no fst change)
sudo mount -o remount,rw,space_cache=v2 mnt
(no warning, no fst change)
Reported-by: Chris Murphy <lists@colorremedies.com>
CC: stable@vger.kernel.org # 5.11
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The problem is we're copying "inherit" from user space but we don't
necessarily know that we're copying enough data for a 64 byte
struct. Then the next problem is that 'inherit' has a variable size
array at the end, and we have to verify that array is the size we
expected.
Fixes: 6f72c7e20d ("Btrfs: add qgroup inheritance")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If btrfs_qgroup_reserve_data returns an error (i.e quota limit reached)
the handling logic directly goes to the 'out' label without first
unlocking the extent range between lockstart, lockend. This results in
deadlocks as other processes try to lock the same extent.
Fixes: a7f8b1c2ac ("btrfs: file: reserve qgroup space after the hole punch range is locked")
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix build warnings of function signature when CONFIG_STACKTRACE is not
enabled by reordering the 'inline' and 'void' keywords.
../fs/btrfs/ref-verify.c:221:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]
static void inline __save_stack_trace(struct ref_action *ra)
../fs/btrfs/ref-verify.c:225:1: warning: ‘inline’ is not at beginning of declaration [-Wold-style-declaration]
static void inline __print_stack_trace(struct btrfs_fs_info *fs_info,
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull kmap conversion updates from David Sterba:
"This contains changes regarding kmap API use and eg conversion from
kmap_atomic to kmap_local_page.
The API belongs to memory management but to save cross-tree
dependency headaches we've agreed to take it through the btrfs tree
because there are some trivial conversions possible, while the rest
will need some time and getting the easy cases out of the way would be
convenient.
The changes can be grouped:
- function exports, new helpers
- new VM_BUG_ON for additional verification; it's been discussed if
it should be VM_BUG_ON or BUG_ON, the former was chosen due to
performance reasons
- code replaced by relevant helpers"
[ This is an updated version of a request that originally came in during
the merge window, but I asked for some updates:
https://lore.kernel.org/lkml/cover.1614090658.git.dsterba@suse.com/
which is why this got merge after the merge window closed. - Linus ]
* 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: use copy_highpage() instead of 2 kmaps()
btrfs: use memcpy_[to|from]_page() and kmap_local_page()
mm/highmem: Add VM_BUG_ON() to mem*_page() calls
mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page()
mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page()
mm/highmem: Lift memcpy_[to|from]_page to core
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Merge tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"This is the first batch of fixes that usually arrive during the merge
window code freeze. Regressions and stable material.
Regressions:
- fix deadlock in log sync in zoned mode
- fix bugs in subpage mode still wrongly assuming sectorsize == page
size
Fixes:
- fix missing kunmap of the Q stripe in RAID6
- block group fixes:
- fix race between extent freeing/allocation when using bitmaps
- avoid double put of block group when emptying cluster
- swapfile fixes:
- fix swapfile writes vs running scrub
- fix swapfile activation vs snapshot creation
- fix stale data exposure after cloning a hole with NO_HOLES enabled
- remove tree-checker check that does not work in case information
from other leaves is necessary"
* tag 'for-5.12-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: fix deadlock on log sync
btrfs: avoid double put of block group when emptying cluster
btrfs: fix stale data exposure after cloning a hole with NO_HOLES enabled
btrfs: tree-checker: do not error out if extent ref hash doesn't match
btrfs: fix race between swap file activation and snapshot creation
btrfs: fix race between writes to swap files and scrub
btrfs: avoid checking for RO block group twice during nocow writeback
btrfs: fix race between extent freeing/allocation when using bitmaps
btrfs: make check_compressed_csum() to be subpage compatible
btrfs: make btrfs_submit_compressed_read() subpage compatible
btrfs: fix raid6 qstripe kmap
There are many places where kmap/memove/kunmap patterns occur.
This pattern exists in the core common function copy_highpage().
Use copy_highpage to avoid open coding the use of kmap and leverages the
core functions use of kmap_local_page().
Development of this patch was aided by the following coccinelle script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/copypage/kunmap pattern and replace with copy_highpage calls
//
// NOTE: The expressions in the copy page version of this kmap pattern are
// overly complex and so these all need individual attention.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// Then a copy_page where we have 2 pages involved.
//
@ copy_page_rule @
expression page, page2, To, From, Size;
identifier ptr, ptr2;
type VP, VP2;
@@
/* kmap */
(
-VP ptr = kmap(page);
...
-VP2 ptr2 = kmap(page2);
|
-VP ptr = kmap_atomic(page);
...
-VP2 ptr2 = kmap_atomic(page2);
|
-ptr = kmap(page);
...
-ptr2 = kmap(page2);
|
-ptr = kmap_atomic(page);
...
-ptr2 = kmap_atomic(page2);
)
// 1 or more copy versions of the entire page
<+...
(
-copy_page(To, From);
+copy_highpage(To, From);
|
-memmove(To, From, Size);
+memmoveExtra(To, From, Size);
)
...+>
/* kunmap */
(
-kunmap(page2);
...
-kunmap(page);
|
-kunmap(page);
...
-kunmap(page2);
|
-kmap_atomic(ptr2);
...
-kmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on copy_page_rule
@
identifier copy_page_rule.ptr;
identifier copy_page_rule.ptr2;
type VP, VP1;
type VP2, VP21;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
-VP2 ptr2;
... when != ptr2;
? VP21 ptr2;
// </smpl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are many places where the pattern kmap/memcpy/kunmap occurs.
This pattern was lifted to the core common functions
memcpy_[to|from]_page().
Use these new functions to reduce the code, eliminate direct uses of
kmap, and leverage the new core functions use of kmap_local_page().
Also, there is 1 place where a kmap/memcpy is followed by an
optional memset. Here we leave the kmap open coded to avoid remapping
the page but use kmap_local_page() directly.
Development of this patch was aided by the coccinelle script:
// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/memcpy/kunmap pattern and replace with memcpy*page calls
//
// NOTE: Offsets and other expressions may be more complex than what the script
// will automatically generate. Therefore a catchall rule is provided to find
// the pattern which then must be evaluated by hand.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:
//
// simple memcpy version
//
@ memcpy_rule1 @
expression page, T, F, B, Off;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
-memcpy(ptr + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(ptr, F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, ptr + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, ptr, B);
+memcpy_from_page(T, page, 0, B);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule1
@
identifier memcpy_rule1.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
//
// Some callers kmap without a temp pointer
//
@ memcpy_rule2 @
expression page, T, Off, F, B;
@@
<+...
(
-memcpy(kmap(page) + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(kmap(page), F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, kmap(page) + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, kmap(page), B);
+memcpy_from_page(T, page, 0, B);
)
...+>
-kunmap(page);
// No need for the ptr variable removal
//
// Catch all
//
@ memcpy_rule3 @
expression page;
expression GenTo, GenFrom, GenSize;
identifier ptr;
type VP;
@@
(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
//
// Some call sites have complex expressions within the memcpy
// match a catch all to be evaluated by hand.
//
-memcpy(GenTo, GenFrom, GenSize);
+memcpy_to_pageExtra(page, GenTo, GenFrom, GenSize);
+memcpy_from_pageExtra(GenTo, page, GenFrom, GenSize);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)
// Remove any pointers left unused
@
depends on memcpy_rule3
@
identifier memcpy_rule3.ptr;
type VP, VP1;
@@
-VP ptr;
... when != ptr;
? VP1 ptr;
// <smpl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Rename generic_file_buffered_read to match the naming of filemap_fault,
also update the written parameter to a more descriptive name and improve
the kerneldoc comment.
Link: https://lkml.kernel.org/r/20210122160140.223228-18-willy@infradead.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdfhttps://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
1d7b902e28
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
Lockdep with fstests test case btrfs/041 detected a unsafe locking
scenario when we allocate the log node on a zoned filesystem.
btrfs/041
============================================
WARNING: possible recursive locking detected
5.11.0-rc7+ #939 Not tainted
--------------------------------------------
xfs_io/698 is trying to acquire lock:
ffff88810cd673a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x3d1/0xee0 [btrfs]
but task is already holding lock:
ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&root->log_mutex);
lock(&root->log_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by xfs_io/698:
#0: ffff88810cd66620 (sb_internal){.+.+}-{0:0}, at: btrfs_sync_file+0x2c3/0x570 [btrfs]
#1: ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]
stack backtrace:
CPU: 0 PID: 698 Comm: xfs_io Not tainted 5.11.0-rc7+ #939
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
Call Trace:
dump_stack+0x77/0x97
__lock_acquire.cold+0xb9/0x32a
lock_acquire+0xb5/0x400
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
__mutex_lock+0x7b/0x8d0
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
? btrfs_sync_log+0x3d1/0xee0 [btrfs]
? find_first_extent_bit+0x9f/0x100 [btrfs]
? __mutex_unlock_slowpath+0x35/0x270
btrfs_sync_log+0x3d1/0xee0 [btrfs]
btrfs_sync_file+0x3a8/0x570 [btrfs]
__x64_sys_fsync+0x34/0x60
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This happens, because we are taking the ->log_mutex albeit it has already
been locked.
Also while at it, fix the bogus unlock of the tree_log_mutex in the error
handling.
Fixes: 3ddebf27fc ("btrfs: zoned: reorder log node allocation on zoned filesystem")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's wrong calling btrfs_put_block_group in
__btrfs_return_cluster_to_free_space if the block group passed is
different than the block group the cluster represents. As this means the
cluster doesn't have a reference to the passed block group. This results
in double put and a use-after-free bug.
Fix this by simply bailing if the block group we passed in does not
match the block group on the cluster.
Fixes: fa9c0d795f ("Btrfs: rework allocation clustering")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
When using the NO_HOLES feature, if we clone a file range that spans only
a hole into a range that is at or beyond the current i_size of the
destination file, we end up not setting the full sync runtime flag on the
inode. As a result, if we then fsync the destination file and have a power
failure, after log replay we can end up exposing stale data instead of
having a hole for that range.
The conditions for this to happen are the following:
1) We have a file with a size of, for example, 1280K;
2) There is a written (non-prealloc) extent for the file range from 1024K
to 1280K with a length of 256K;
3) This particular file extent layout is durably persisted, so that the
existing superblock persisted on disk points to a subvolume root where
the file has that exact file extent layout and state;
4) The file is truncated to a smaller size, to an offset lower than the
start offset of its last extent, for example to 800K. The truncate sets
the full sync runtime flag on the inode;
6) Fsync the file to log it and clear the full sync runtime flag;
7) Clone a region that covers only a hole (implicit hole due to NO_HOLES)
into the file with a destination offset that starts at or beyond the
256K file extent item we had - for example to offset 1024K;
8) Since the clone operation does not find extents in the source range,
we end up in the if branch at the bottom of btrfs_clone() where we
punch a hole for the file range starting at offset 1024K by calling
btrfs_replace_file_extents(). There we end up not setting the full
sync flag on the inode, because we don't know we are being called in
a clone context (and not fallocate's punch hole operation), and
neither do we create an extent map to represent a hole because the
requested range is beyond eof;
9) A further fsync to the file will be a fast fsync, since the clone
operation did not set the full sync flag, and therefore it relies on
modified extent maps to correctly log the file layout. But since
it does not find any extent map marking the range from 1024K (the
previous eof) to the new eof, it does not log a file extent item
for that range representing the hole;
10) After a power failure no hole for the range starting at 1024K is
punched and we end up exposing stale data from the old 256K extent.
Turning this into exact steps:
$ mkfs.btrfs -f -O no-holes /dev/sdi
$ mount /dev/sdi /mnt
# Create our test file with 3 extents of 256K and a 256K hole at offset
# 256K. The file has a size of 1280K.
$ xfs_io -f -s \
-c "pwrite -S 0xab -b 256K 0 256K" \
-c "pwrite -S 0xcd -b 256K 512K 256K" \
-c "pwrite -S 0xef -b 256K 768K 256K" \
-c "pwrite -S 0x73 -b 256K 1024K 256K" \
/mnt/sdi/foobar
# Make sure it's durably persisted. We want the last committed super
# block to point to this particular file extent layout.
sync
# Now truncate our file to a smaller size, falling within a position of
# the second extent. This sets the full sync runtime flag on the inode.
# Then fsync the file to log it and clear the full sync flag from the
# inode. The third extent is no longer part of the file and therefore
# it is not logged.
$ xfs_io -c "truncate 800K" -c "fsync" /mnt/foobar
# Now do a clone operation that only clones the hole and sets back the
# file size to match the size it had before the truncate operation
# (1280K).
$ xfs_io \
-c "reflink /mnt/foobar 256K 1024K 256K" \
-c "fsync" \
/mnt/foobar
# File data before power failure:
$ od -A d -t x1 /mnt/foobar
0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
*
0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
*
0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
*
0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
1310720
<power fail>
# Mount the fs again to replay the log tree.
$ mount /dev/sdi /mnt
# File data after power failure:
$ od -A d -t x1 /mnt/foobar
0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
*
0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
*
0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
*
0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
1048576 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73
*
1310720
The range from 1024K to 1280K should correspond to a hole but instead it
points to stale data, to the 256K extent that should not exist after the
truncate operation.
The issue does not exists when not using NO_HOLES, because for that case
we use file extent items to represent holes, these are found and copied
during the loop that iterates over extents at btrfs_clone(), and that
causes btrfs_replace_file_extents() to be called with a non-NULL
extent_info argument and therefore set the full sync runtime flag on the
inode.
So fix this by making the code that deals with a trailing hole during
cloning, at btrfs_clone(), to set the full sync flag on the inode, if the
range starts at or beyond the current i_size.
A test case for fstests will follow soon.
Backporting notes: for kernel 5.4 the change goes to ioctl.c into
btrfs_clone before the last call to btrfs_punch_hole_range.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The tree checker checks the extent ref hash at read and write time to
make sure we do not corrupt the file system. Generally extent
references go inline, but if we have enough of them we need to make an
item, which looks like
key.objectid = <bytenr>
key.type = <BTRFS_EXTENT_DATA_REF_KEY|BTRFS_TREE_BLOCK_REF_KEY>
key.offset = hash(tree, owner, offset)
However if key.offset collide with an unrelated extent reference we'll
simply key.offset++ until we get something that doesn't collide.
Obviously this doesn't match at tree checker time, and thus we error
while writing out the transaction. This is relatively easy to
reproduce, simply do something like the following
xfs_io -f -c "pwrite 0 1M" file
offset=2
for i in {0..10000}
do
xfs_io -c "reflink file 0 ${offset}M 1M" file
offset=$(( offset + 2 ))
done
xfs_io -c "reflink file 0 17999258914816 1M" file
xfs_io -c "reflink file 0 35998517829632 1M" file
xfs_io -c "reflink file 0 53752752058368 1M" file
btrfs filesystem sync
And the sync will error out because we'll abort the transaction. The
magic values above are used because they generate hash collisions with
the first file in the main subvol.
The fix for this is to remove the hash value check from tree checker, as
we have no idea which offset ours should belong to.
Reported-by: Tuomas Lähdekorpi <tuomas.lahdekorpi@gmail.com>
Fixes: 0785a9aacf ("btrfs: tree-checker: Add EXTENT_DATA_REF check")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment]
Signed-off-by: David Sterba <dsterba@suse.com>
When creating a snapshot we check if the current number of swap files, in
the root, is non-zero, and if it is, we error out and warn that we can not
create the snapshot because there are active swap files.
However this is racy because when a task started activation of a swap
file, another task might have started already snapshot creation and might
have seen the counter for the number of swap files as zero. This means
that after the swap file is activated we may end up with a snapshot of the
same root successfully created, and therefore when the first write to the
swap file happens it has to fall back into COW mode, which should never
happen for active swap files.
Basically what can happen is:
1) Task A starts snapshot creation and enters ioctl.c:create_snapshot().
There it sees that root->nr_swapfiles has a value of 0 so it continues;
2) Task B enters btrfs_swap_activate(). It is not aware that another task
started snapshot creation but it did not finish yet. It increments
root->nr_swapfiles from 0 to 1;
3) Task B checks that the file meets all requirements to be an active
swap file - it has NOCOW set, there are no snapshots for the inode's
root at the moment, no file holes, no reflinked extents, etc;
4) Task B returns success and now the file is an active swap file;
5) Task A commits the transaction to create the snapshot and finishes.
The swap file's extents are now shared between the original root and
the snapshot;
6) A write into an extent of the swap file is attempted - there is a
snapshot of the file's root, so we fall back to COW mode and therefore
the physical location of the extent changes on disk.
So fix this by taking the snapshot lock during swap file activation before
locking the extent range, as that is the order in which we lock these
during buffered writes.
Fixes: ed46ff3d42 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we active a swap file, at btrfs_swap_activate(), we acquire the
exclusive operation lock to prevent the physical location of the swap
file extents to be changed by operations such as balance and device
replace/resize/remove. We also call there can_nocow_extent() which,
among other things, checks if the block group of a swap file extent is
currently RO, and if it is we can not use the extent, since a write
into it would result in COWing the extent.
However we have no protection against a scrub operation running after we
activate the swap file, which can result in the swap file extents to be
COWed while the scrub is running and operating on the respective block
group, because scrub turns a block group into RO before it processes it
and then back again to RW mode after processing it. That means an attempt
to write into a swap file extent while scrub is processing the respective
block group, will result in COWing the extent, changing its physical
location on disk.
Fix this by making sure that block groups that have extents that are used
by active swap files can not be turned into RO mode, therefore making it
not possible for a scrub to turn them into RO mode. When a scrub finds a
block group that can not be turned to RO due to the existence of extents
used by swap files, it proceeds to the next block group and logs a warning
message that mentions the block group was skipped due to active swap
files - this is the same approach we currently use for balance.
Fixes: ed46ff3d42 ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During the nocow writeback path, we currently iterate the rbtree of block
groups twice: once for checking if the target block group is RO with the
call to btrfs_extent_readonly()), and once again for getting a nocow
reference on the block group with a call to btrfs_inc_nocow_writers().
Since btrfs_inc_nocow_writers() already returns false when the target
block group is RO, remove the call to btrfs_extent_readonly(). Not only
we avoid searching the blocks group rbtree twice, it also helps reduce
contention on the lock that protects it (specially since it is a spin
lock and not a read-write lock). That may make a noticeable difference
on very large filesystems, with thousands of allocated block groups.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During allocation the allocator will try to allocate an extent using
cluster policy. Once the current cluster is exhausted it will remove the
entry under btrfs_free_cluster::lock and subsequently acquire
btrfs_free_space_ctl::tree_lock to dispose of the already-deleted entry
and adjust btrfs_free_space_ctl::total_bitmap. This poses a problem
because there exists a race condition between removing the entry under
one lock and doing the necessary accounting holding a different lock
since extent freeing only uses the 2nd lock. This can result in the
following situation:
T1: T2:
btrfs_alloc_from_cluster insert_into_bitmap <holds tree_lock>
if (entry->bytes == 0) if (block_group && !list_empty(&block_group->cluster_list)) {
rb_erase(entry)
spin_unlock(&cluster->lock);
(total_bitmaps is still 4) spin_lock(&cluster->lock);
<doesn't find entry in cluster->root>
spin_lock(&ctl->tree_lock); <goes to new_bitmap label, adds
<blocked since T2 holds tree_lock> <a new entry and calls add_new_bitmap>
recalculate_thresholds <crashes,
due to total_bitmaps
becoming 5 and triggering
an ASSERT>
To fix this ensure that once depleted, the cluster entry is deleted when
both cluster lock and tree locks are held in the allocator (T1), this
ensures that even if there is a race with a concurrent
insert_into_bitmap call it will correctly find the entry in the cluster
and add the new space to it.
CC: <stable@vger.kernel.org> # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently check_compressed_csum() completely relies on sectorsize ==
PAGE_SIZE to do checksum verification for compressed extents.
To make it subpage compatible, this patch will:
- Do extra calculation for the csum range
Since we have multiple sectors inside a page, we need to only hash
the range we want, not the full page anymore.
- Do sector-by-sector hash inside the page
With this patch and previous conversion on
btrfs_submit_compressed_read(), now we can read subpage compressed
extents properly, and do proper csum verification.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For compressed read, we always submit page read using page size. This
doesn't work well with subpage, as for subpage one page can contain
several sectors. Such submission will read range out of what we want,
and cause problems.
Thankfully to make it subpage compatible, we only need to change how the
last page of the compressed extent is read.
Instead of always adding a full page to the compressed read bio, if we're
at the last page, calculate the size using compressed length, so that we
only add part of the range into the compressed read bio.
Since we are here, also change the PAGE_SIZE used in
lookup_extent_mapping() to sectorsize.
This modification won't cause any functional change, as
lookup_extent_mapping() can handle the case where the search range is
larger than found extent range.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a qstripe is required an extra page is allocated and mapped. There
were 3 problems:
1) There is no corresponding call of kunmap() for the qstripe page.
2) There is no reason to map the qstripe page more than once if the
number of bits set in rbio->dbitmap is greater than one.
3) There is no reason to map the parity page and unmap it each time
through the loop.
The page memory can continue to be reused with a single mapping on each
iteration by raid6_call.gen_syndrome() without remapping. So map the
page for the duration of the loop.
Similarly, improve the algorithm by mapping the parity page just 1 time.
Fixes: 5a6ac9eacb ("Btrfs, raid56: support parity scrub on raid56")
CC: stable@vger.kernel.org # 4.4.x: c17af96554: btrfs: raid56: simplify tracking of Q stripe presence
CC: stable@vger.kernel.org # 4.4.x
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
"Another nice round of removing more code than what is added, mostly
due to Christoph's relentless pursuit of tech debt removal/cleanups.
This pull request contains:
- Two series of BFQ improvements (Paolo, Jan, Jia)
- Block iov_iter improvements (Pavel)
- bsg error path fix (Pan)
- blk-mq scheduler improvements (Jan)
- -EBUSY discard fix (Jan)
- bvec allocation improvements (Ming, Christoph)
- bio allocation and init improvements (Christoph)
- Store bdev pointer in bio instead of gendisk + partno (Christoph)
- Block trace point cleanups (Christoph)
- hard read-only vs read-only split (Christoph)
- Block based swap cleanups (Christoph)
- Zoned write granularity support (Damien)
- Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)"
* tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits)
mm: simplify swapdev_block
sd_zbc: clear zone resources for non-zoned case
block: introduce blk_queue_clear_zone_settings()
zonefs: use zone write granularity as block size
block: introduce zone_write_granularity limit
block: use blk_queue_set_zoned in add_partition()
nullb: use blk_queue_set_zoned() to setup zoned devices
nvme: cleanup zone information initialization
block: document zone_append_max_bytes attribute
block: use bi_max_vecs to find the bvec pool
md/raid10: remove dead code in reshape_request
block: mark the bio as cloned in bio_iov_bvec_set
block: set BIO_NO_PAGE_REF in bio_iov_bvec_set
block: remove a layer of indentation in bio_iov_iter_get_pages
block: turn the nr_iovecs argument to bio_alloc* into an unsigned short
block: remove the 1 and 4 vec bvec_slabs entries
block: streamline bvec_alloc
block: factor out a bvec_alloc_gfp helper
block: move struct biovec_slab to bio.c
block: reuse BIO_INLINE_VECS for integrity bvecs
...
- Adjust the final parameter of iomap_dio_rw.
- Add a new flag to request that iomap directio writes return EAGAIN if
the write is not a pure overwrite within EOF; this will be used to
reduce lock contention with unaligned direct writes on XFS.
- Amend XFS' directio code to eliminate exclusive locking for unaligned
direct writes if the circumstances permit
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Merge tag 'iomap-5.12-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"The big change in this cycle is some new code to make it possible for
XFS to try unaligned directio overwrites without taking locks. If the
block is fully written and within EOF (i.e. doesn't require any
further fs intervention) then we can let the unlocked write proceed.
If not, we fall back to synchronizing direct writes.
Summary:
- Adjust the final parameter of iomap_dio_rw.
- Add a new flag to request that iomap directio writes return EAGAIN
if the write is not a pure overwrite within EOF; this will be used
to reduce lock contention with unaligned direct writes on XFS.
- Amend XFS' directio code to eliminate exclusive locking for
unaligned direct writes if the circumstances permit"
* tag 'iomap-5.12-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: reduce exclusive locking on unaligned dio
xfs: split the unaligned DIO write code out
xfs: improve the reflink_bounce_dio_write tracepoint
xfs: simplify the read/write tracepoints
xfs: remove the buffered I/O fallback assert
xfs: cleanup the read/write helper naming
xfs: make xfs_file_aio_write_checks IOCB_NOWAIT-aware
xfs: factor out a xfs_ilock_iocb helper
iomap: add a IOMAP_DIO_OVERWRITE_ONLY flag
iomap: pass a flags argument to iomap_dio_rw
iomap: rename the flags variable in __iomap_dio_rw
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Merge tag 'for-5.12-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This brings updates of space handling, performance improvements or bug
fixes. The subpage block size and zoned mode features have reached
state where they're usable but with limitations.
Performance or related:
- do not block on deleted block group mutex in the cleaner, avoids
some long stalls
- improved flushing: make it work better with ticket space
reservations and avoid excessive transaction commits in some
scenarios, slightly improves throughput for random write load
- preemptive background flushing: separate the logic from ticket
reservations, improve the accounting and decisions when to flush in
low space conditions
- less lock contention related to running delayed refs, let just one
thread do the flushing when there are many inside transaction
commit
- dbench workload improvements: avoid unnecessary work when logging
inodes, fewer fallbacks to transaction commit and thus less waiting
for it (+7% throughput, -20% latency)
Core:
- subpage block size
- currently read-only support
- refactor and generalize code where sectorsize is assumed to be
page size, add the subpage handling everywhere
- the read-write support is on the way, page sizes are still
limited to 4K or 64K
- zoned mode, first working version but with limitations
- SMR/ZBC/ZNS friendly allocation mode, utilizing the "no fixed
location for structures" and chunked allocation
- superblock as the only fixed data structure needs special
handling, uses 2 consecutive zones as a ring buffer
- tree-log support with a dedicated block group to avoid unordered
writes
- emulated zones on non-zoned devices
- not yet working
- all non-single block group profiles, requires more zone write
pointer synchronization between the multiple block groups
- fitrim due to dependency on space cache, can be implemented
Fixes:
- ref-verify: proper tree owner and node level tracking
- fix pinned byte accounting, causing some early ENOSPC now more
likely due to other changes in delayed refs
Other:
- error handling fixes and improvements
- more error injection points
- more function documentation
- more and updated tracepoints
- subset of W=1 checked by default
- update comments to allow more automatic kdoc parameter checks"
* tag 'for-5.12-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (144 commits)
btrfs: zoned: enable to mount ZONED incompat flag
btrfs: zoned: deal with holes writing out tree-log pages
btrfs: zoned: reorder log node allocation on zoned filesystem
btrfs: zoned: serialize log transaction on zoned filesystems
btrfs: zoned: extend zoned allocator to use dedicated tree-log block group
btrfs: split alloc_log_tree()
btrfs: zoned: relocate block group to repair IO failure in zoned filesystems
btrfs: zoned: enable relocation on a zoned filesystem
btrfs: zoned: support dev-replace in zoned filesystems
btrfs: zoned: implement copying for zoned device-replace
btrfs: zoned: implement cloning for zoned device-replace
btrfs: zoned: mark block groups to copy for device-replace
btrfs: zoned: do not use async metadata checksum on zoned filesystems
btrfs: zoned: wait for existing extents before truncating
btrfs: zoned: serialize metadata IO
btrfs: zoned: introduce dedicated data write path for zoned filesystems
btrfs: zoned: enable zone append writing for direct IO
btrfs: zoned: use ZONE_APPEND write for zoned mode
btrfs: save irq flags when looking up an ordered extent
btrfs: zoned: cache if block group is on a sequential zone
...
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Merge tag 'for-5.11-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fix from David Sterba:
"A regression fix caused by a refactoring in 5.11.
A corrupted superblock wouldn't be detected by checksum verification
due to wrongly placed initialization of the checksum length, thus
making memcmp always work"
* tag 'for-5.11-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: initialize fs_info::csum_size earlier in open_ctree
User reported that btrfs-progs misc-tests/028-superblock-recover fails:
[TEST/misc] 028-superblock-recover
unexpected success: mounted fs with corrupted superblock
test failed for case 028-superblock-recover
The test case expects that a broken image with bad superblock will be
rejected to be mounted. However, the test image just passed csum check
of superblock and was successfully mounted.
Commit 55fc29bed8 ("btrfs: use cached value of fs_info::csum_size
everywhere") replaces all calls to btrfs_super_csum_size by
fs_info::csum_size. The calls include the place where fs_info->csum_size
is not initialized. So btrfs_check_super_csum() passes because memcmp()
with len 0 always returns 0.
Fix it by caching csum size in btrfs_fs_info::csum_size once we know the
csum type in superblock is valid in open_ctree().
Link: https://github.com/kdave/btrfs-progs/issues/250
Fixes: 55fc29bed8 ("btrfs: use cached value of fs_info::csum_size everywhere")
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This final patch adds the ZONED incompat flag to the supported flags
and enables to mount ZONED flagged file system.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since the zoned filesystem requires sequential write out of metadata, we
cannot proceed with a hole in tree-log pages. When such a hole exists,
btree_write_cache_pages() will return -EAGAIN. This happens when someone,
e.g., a concurrent transaction commit, writes a dirty extent in this
tree-log commit.
If we are not going to wait for the extents, we can hope the concurrent
writing fills the hole for us. So, we can ignore the error in this case and
hope the next write will succeed.
If we want to wait for them and got the error, we cannot wait for them
because it will cause a deadlock. So, let's bail out to a full commit in
this case.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is the 3/3 patch to enable tree-log on zoned filesystems.
The allocation order of nodes of "fs_info->log_root_tree" and nodes of
"root->log_root" is not the same as the writing order of them. So, the
writing causes unaligned write errors.
Reorder the allocation of them by delaying allocation of the root node of
"fs_info->log_root_tree," so that the node buffers can go out sequentially
to devices.
Cc: Filipe Manana <fdmanana@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is the 2/3 patch to enable tree-log on zoned filesystems.
Since we can start more than one log transactions per subvolume
simultaneously, nodes from multiple transactions can be allocated
interleaved. Such mixed allocation results in non-sequential writes at
the time of a log transaction commit. The nodes of the global log root
tree (fs_info->log_root_tree), also have the same problem with mixed
allocation.
Serializes log transactions by waiting for a committing transaction when
someone tries to start a new transaction, to avoid the mixed allocation
problem. We must also wait for running log transactions from another
subvolume, but there is no easy way to detect which subvolume root is
running a log transaction. So, this patch forbids starting a new log
transaction when other subvolumes already allocated the global log root
tree.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is the 1/3 patch to enable tree log on zoned filesystems.
The tree-log feature does not work on a zoned filesystem as is. Blocks for
a tree-log tree are allocated mixed with other metadata blocks and btrfs
writes and syncs the tree-log blocks to devices at the time of fsync(),
which has a different timing than a global transaction commit. As a
result, both writing tree-log blocks and writing other metadata blocks
become non-sequential writes that zoned filesystems must avoid.
Introduce a dedicated block group for tree-log blocks, so that tree-log
blocks and other metadata blocks can be separate write streams. As a
result, each write stream can now be written to devices separately.
"fs_info->treelog_bg" tracks the dedicated block group and assigns
"treelog_bg" on-demand on tree-log block allocation time.
This commit extends the zoned block allocator to use the block group.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a preparation patch for the next patch. Split alloc_log_tree()
into two parts. The first one allocating the tree structure, remains in
alloc_log_tree() and the second part allocating the tree node, which is
moved into btrfs_alloc_log_tree_node().
Also export the latter part is to be used in the next patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a bad checksum is found and if the filesystem has a mirror of the
damaged data, we read the correct data from the mirror and writes it to
damaged blocks. This however, violates the sequential write constraints
of a zoned block device.
We can consider three methods to repair an IO failure in zoned filesystems:
(1) Reset and rewrite the damaged zone
(2) Allocate new device extent and replace the damaged device extent to
the new extent
(3) Relocate the corresponding block group
Method (1) is most similar to a behavior done with regular devices.
However, it also wipes non-damaged data in the same device extent, and
so it unnecessary degrades non-damaged data.
Method (2) is much like device replacing but done in the same device. It
is safe because it keeps the device extent until the replacing finish.
However, extending device replacing is non-trivial. It assumes
"src_dev->physical == dst_dev->physical". Also, the extent mapping
replacing function should be extended to support replacing device extent
position in one device.
Method (3) invokes relocation of the damaged block group and is
straightforward to implement. It relocates all the mirrored device
extents, so it potentially is a more costly operation than method (1) or
(2). But it relocates only used extents which reduce the total IO size.
Let's apply method (3) for now. In the future, we can extend device-replace
and apply method (2).
For protecting a block group gets relocated multiple time with multiple
IO errors, this commit introduces "relocating_repair" bit to show it's
now relocating to repair IO failures. Also it uses a new kthread
"btrfs-relocating-repair", not to block IO path with relocating process.
This commit also supports repairing in the scrub process.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently fallocate() is disabled on a zoned filesystem. Since current
relocation process relies on preallocation to move file data extents, it
must be handled differently.
On a zoned filesystem, we just truncate the inode to the size that we
wanted to pre-allocate. Then, we flush dirty pages on the file before
finishing the relocation process. run_delalloc_zoned() will handle all
the allocations and submit IOs to the underlying layers.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is 4/4 patch to implement device-replace on zoned filesystems.
Even after the copying is done, the write pointers of the source device
and the destination device may not be synchronized. For example, when
the last allocated extent is freed before device-replace process, the
extent is not copied, leaving a hole there.
Synchronize the write pointers by writing zeroes to the destination
device.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is 3/4 patch to implement device-replace on zoned filesystems.
This commit implements copying. To do this, it tracks the write pointer
during the device replace process. As device-replace's copy process is
smart enough to only copy used extents on the source device, we have to
fill the gap to honor the sequential write requirement in the target
device.
The device-replace process on zoned filesystems must copy or clone all
the extents in the source device exactly once. So, we need to ensure
allocations started just before the dev-replace process to have their
corresponding extent information in the B-trees.
finish_extent_writes_for_zoned() implements that functionality, which
basically is the removed code in the commit 042528f8d8 ("Btrfs: fix
block group remaining RO forever after error during device replace").
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is 2/4 patch to implement device replace for zoned filesystems.
In zoned mode, a block group must be either copied (from the source
device to the target device) or cloned (to both devices).
Implement the cloning part. If a block group targeted by an IO is marked
to copy, we should not clone the IO to the destination device, because
the block group is eventually copied by the replace process.
This commit also handles cloning of device reset.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is the 1/4 patch to support device-replace on zoned filesystems.
We have two types of IOs during the device replace process. One is an IO
to "copy" (by the scrub functions) all the device extents from the source
device to the destination device. The other one is an IO to "clone" (by
handle_ops_on_dev_replace()) new incoming write IOs from users to the
source device into the target device.
Cloning incoming IOs can break the sequential write rule in on target
device. When a write is mapped in the middle of a block group, the IO is
directed to the middle of a target device zone, which breaks the
sequential write requirement.
However, the cloning function cannot be disabled since incoming IOs
targeting already copied device extents must be cloned so that the IO is
executed on the target device.
We cannot use dev_replace->cursor_{left,right} to determine whether a bio
is going to a not yet copied region. Since we have a time gap between
finishing btrfs_scrub_dev() and rewriting the mapping tree in
btrfs_dev_replace_finishing(), we can have a newly allocated device extent
which is never cloned nor copied.
So the point is to copy only already existing device extents. This patch
introduces mark_block_group_to_copy() to mark existing block groups as a
target of copying. Then, handle_ops_on_dev_replace() and dev-replace can
check the flag to do their job.
Also, btrfs_finish_block_group_to_copy() will check if the copied stripe
is the last stripe in the block group. With the last stripe copied,
the to_copy flag is finally disabled. Afterwards we can safely clone
incoming IOs on this block group.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
On zoned filesystems, btrfs uses per-fs zoned_meta_io_lock to serialize
the metadata write IOs.
Even with this serialization, write bios sent from btree_write_cache_pages
can be reordered by async checksum workers as these workers are per CPU
and not per zone.
To preserve write bio ordering, we disable async metadata checksum on a
zoned filesystem. This does not result in lower performance with HDDs as
a single CPU core is fast enough to do checksum for a single zone write
stream with the maximum possible bandwidth of the device. If multiple
zones are being written simultaneously, HDD seek overhead lowers the
achievable maximum bandwidth, resulting again in a per zone checksum
serialization not affecting the performance.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When truncating a file, file buffers which have already been allocated
but not yet written may be truncated. Truncating these buffers could
cause breakage of a sequential write pattern in a block group if the
truncated blocks are for example followed by blocks allocated to another
file. To avoid this problem, always wait for write out of all unwritten
buffers before proceeding with the truncate execution.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We cannot use zone append for writing metadata, because the B-tree nodes
have references to each other using logical address. Without knowing
the address in advance, we cannot construct the tree in the first place.
So we need to serialize write IOs for metadata.
We cannot add a mutex around allocation and submission because metadata
blocks are allocated in an earlier stage to build up B-trees.
Add a zoned_meta_io_lock and hold it during metadata IO submission in
btree_write_cache_pages() to serialize IOs.
Furthermore, this adds a per-block group metadata IO submission pointer
"meta_write_pointer" to ensure sequential writing, which can break when
attempting to write back blocks in an unfinished transaction. If the
writing out failed because of a hole and the write out is for data
integrity (WB_SYNC_ALL), it returns EAGAIN.
A caller like fsync() code should handle this properly e.g. by falling
back to a full transaction commit.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If more than one IO is issued for one file extent, these IO can be
written to separate regions on a device. Since we cannot map one file
extent to such a separate area on a zoned filesystem, we need to follow
the "one IO == one ordered extent" rule.
The normal buffered, uncompressed and not pre-allocated write path (used
by cow_file_range()) sometimes does not follow this rule. It can write a
part of an ordered extent when specified a region to write e.g., when
its called from fdatasync().
Introduce a dedicated (uncompressed buffered) data write path for zoned
filesystems, that will COW the region and write it at once.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Likewise to buffered IO, enable zone append writing for direct IO when
its used on a zoned block device.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Enable zone append writing for zoned mode. When using zone append, a
bio is issued to the start of a target zone and the device decides to
place it inside the zone. Upon completion the device reports the actual
written position back to the host.
Three parts are necessary to enable zone append mode. First, modify the
bio to use REQ_OP_ZONE_APPEND in btrfs_submit_bio_hook() and adjust the
bi_sector to point the beginning of the zone.
Second, record the returned physical address (and disk/partno) to the
ordered extent in end_bio_extent_writepage() after the bio has been
completed. We cannot resolve the physical address to the logical address
because we can neither take locks nor allocate a buffer in this end_bio
context. So, we need to record the physical address to resolve it later
in btrfs_finish_ordered_io().
And finally, rewrite the logical addresses of the extent mapping and
checksum data according to the physical address using btrfs_rmap_block.
If the returned address matches the originally allocated address, we can
skip this rewriting process.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A following patch will add another caller of
btrfs_lookup_ordered_extent(), but from a bio's endio context.
btrfs_lookup_ordered_extent() uses spin_lock_irq() which unconditionally
disables interrupts. Change this to spin_lock_irqsave() so interrupts
aren't disabled and re-enabled unconditionally.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
On a zoned filesystem, cache if a block group is on a sequential write
only zone.
On sequential write only zones, we can use REQ_OP_ZONE_APPEND for
writing data, therefore provide btrfs_use_zone_append() to figure out if
IO is targeting a sequential write only zone and we can use
REQ_OP_ZONE_APPEND for data writing.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_rmap_block currently reverse-maps the physical addresses on all
devices to the corresponding logical addresses.
Extend the function to match to a specified device. The old functionality
of querying all devices is left intact by specifying NULL as target
device.
A block_device instead of a btrfs_device is passed into btrfs_rmap_block,
as this function is intended to reverse-map the result of a bio, which
only has a block_device.
Also export the function for later use.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To ensure that an ordered extent maps to a contiguous region on disk, we
need to maintain a "one bio == one ordered extent" rule.
Ensure that constructing bio does not span more than an ordered extent.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For a zone append write, the device decides the location the data is being
written to. Therefore we cannot ensure that two bios are written
consecutively on the device. In order to ensure that an ordered extent
maps to a contiguous region on disk, we need to maintain a "one bio ==
one ordered extent" rule.
Implement splitting of an ordered extent and extent map on bio submission
to adhere to the rule.
extract_ordered_extent() hooks into btrfs_submit_data_bio() and splits the
corresponding ordered extent so that the ordered extent's region fits into
one bio and the corresponding device limits.
Several sanity checks need to be done in extract_ordered_extent() e.g.
- We cannot split once end_bio'd ordered extent because we cannot divide
ordered->bytes_left for the split ones
- We do not expect a compressed ordered extent
- We should not have checksum list because we omit the list splitting.
Since the function is called before btrfs_wq_submit_bio() or
btrfs_csum_one_bio(), this should be always ensured.
We also need to split an extent map by creating a new one. If not,
unpin_extent_cache() complains about the difference between the start of
the extent map and the file's logical offset.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Zoned filesystems use REQ_OP_ZONE_APPEND bios for writing to actual
devices.
Let btrfs_end_bio() and btrfs_op be aware of it, by mapping
REQ_OP_ZONE_APPEND to BTRFS_MAP_WRITE and using btrfs_op() instead of
bio_op().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A zoned device has its own hardware restrictions e.g. max_zone_append_size
when using REQ_OP_ZONE_APPEND. To follow these restrictions, use
bio_add_zone_append_page() instead of bio_add_page(). We need target device
to use bio_add_zone_append_page(), so this commit reads the chunk
information to cache the target device to btrfs_io_bio(bio)->device.
Caching only the target device is sufficient here as zoned filesystems
only supports the single profile at the moment. Once more profiles will be
supported btrfs_io_bio can hold an extent_map to be able to check for the
restrictions of all devices the btrfs_bio will be mapped to.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out adding a page to a bio from submit_extent_page(). The page
is added only when bio_flags are the same, contiguous and the added page
fits in the same stripe as pages in the bio.
Condition checks are reordered to allow early return to avoid possibly
heavy btrfs_bio_fits_in_stripe() calling.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We must reset the zones of a deleted unused block group to rewind the
zones' write pointers to the zones' start.
To do this, we can use the DISCARD_SYNC code to do the reset when the
filesystem is running on zoned devices.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since the allocation info of a tree log node is not recorded in the extent
tree, calculate_alloc_pointer() cannot detect this node, so the pointer
can be over a tree node.
Replaying the log calls btrfs_remove_free_space() for each node in the
log tree.
So, advance the pointer after the node to not allocate over it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Tree manipulating operations like merging nodes often release
once-allocated tree nodes. Such nodes are cleaned so that pages in the
node are not uselessly written out. On zoned volumes, however, such
optimization blocks the following IOs as the cancellation of the write
out of the freed blocks breaks the sequential write sequence expected by
the device.
Introduce a list of clean and unwritten extent buffers that have been
released in a transaction. Redirty the buffers so that
btree_write_cache_pages() can send proper bios to the devices.
Besides it clears the entire content of the extent buffer not to confuse
raw block scanners e.g. 'btrfs check'. By clearing the content,
csum_dirty_buffer() complains about bytenr mismatch, so avoid the
checking and checksum using newly introduced buffer flag
EXTENT_BUFFER_NO_CHECK.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Implement a sequential extent allocator for zoned filesystems. This
allocator only needs to check if there is enough space in the block group
after the allocation pointer to satisfy the extent allocation request.
Therefore the allocator never manages bitmaps or clusters. Also, add
assertions to the corresponding functions.
As zone append writing is used, it would be unnecessary to track the
allocation offset, as the allocator only needs to check available space.
But by tracking and returning the offset as an allocated region, we can
skip modification of ordered extents and checksum information when there
is no IO reordering.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In a zoned filesystem a once written then freed region is not usable
until the underlying zone has been reset. So we need to distinguish such
unusable space from usable free space.
Therefore we need to introduce the "zone_unusable" field to the block
group structure, and "bytes_zone_unusable" to the space_info structure
to track the unusable space.
Pinned bytes are always reclaimed to the unusable space. But, when an
allocated region is returned before using e.g., the block group becomes
read-only between allocation time and reservation time, we can safely
return the region to the block group. For the situation, this commit
introduces "btrfs_add_free_space_unused". This behaves the same as
btrfs_add_free_space() on regular filesystem. On zoned filesystems, it
rewinds the allocation offset.
Because the read-only bytes tracks free but unusable bytes when the block
group is read-only, we need to migrate the zone_unusable bytes to
read-only bytes when a block group is marked read-only.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Conventional zones do not have a write pointer, so we cannot use it to
determine the allocation offset for sequential allocation if a block
group contains a conventional zone.
But instead, we can consider the end of the highest addressed extent in
the block group for the allocation offset.
For new block group, we cannot calculate the allocation offset by
consulting the extent tree, because it can cause deadlock by taking
extent buffer lock after chunk mutex, which is already taken in
btrfs_make_block_group(). Since it is a new block group anyways, we can
simply set the allocation offset to 0.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A zoned filesystem must allocate blocks at the zones' write pointer. The
device's write pointer position can be mapped to a logical address within
a block group. To facilitate this, add an "alloc_offset" to the
block-group to track the logical addresses of the write pointer.
This logical address is populated in btrfs_load_block_group_zone_info()
from the write pointers of corresponding zones.
For now, zoned filesystems the single profile. Supporting non-single
profile with zone append writing is not trivial. For example, in the DUP
profile, we send a zone append writing IO to two zones on a device. The
device reply with written LBAs for the IOs. If the offsets of the
returned addresses from the beginning of the zone are different, then it
results in different logical addresses.
We need fine-grained logical to physical mapping to support such separated
physical address issue. Since it should require additional metadata type,
disable non-single profiles for now.
This commit supports the case all the zones in a block group are
sequential. The next patch will handle the case having a conventional
zone.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a check in verify_one_dev_extent() to ensure that a device extent on
a zoned block device is aligned to the respective zone boundary.
If it isn't, mark the filesystem as unclean.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Implement a zoned chunk and device extent allocator. One device zone
becomes a device extent so that a zone reset affects only this device
extent and does not change the state of blocks in the neighbor device
extents.
To implement the allocator, we need to extend the following functions for
a zoned filesystem.
- init_alloc_chunk_ctl
- dev_extent_search_start
- dev_extent_hole_check
- decide_stripe_size
init_alloc_chunk_ctl_zoned() is mostly the same as regular one. It always
set the stripe_size to the zone size and aligns the parameters to the zone
size.
dev_extent_search_start() only aligns the start offset to zone boundaries.
We don't care about the first 1MB like in regular filesystem because we
anyway reserve the first two zones for superblock logging.
dev_extent_hole_check_zoned() checks if zones in given hole are either
conventional or empty sequential zones. Also, it skips zones reserved for
superblock logging.
With the change to the hole, the new hole may now contain pending extents.
So, in this case, loop again to check that.
Finally, decide_stripe_size_zoned() should shrink the number of devices
instead of stripe size because we need to honor stripe_size == zone_size.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Run a zoned filesystem on non-zoned devices. This is done by "slicing up"
the block device into static sized chunks and fake a conventional zone on
each of them. The emulated zone size is determined from the size of device
extent.
This is mainly aimed at testing of zoned filesystems, i.e. the zoned
chunk allocator, on regular block devices.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The implementation of fitrim depends on space cache, which is not used
and disabled for zoned extent allocator. So the current code does not
work with zoned filesystem.
In the future, we can implement fitrim for zoned filesystems by enabling
space cache (but, only for fitrim) or scanning the extent tree at fitrim
time. For now, disallow fitrim on zoned filesystems.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Don't set the zoned flag in fs_info as soon as we're encountering the
incompat filesystem flag for a zoned filesystem on mount. The zoned flag
in fs_info is in a union together with the zone_size, so setting it too
early will result in setting an incorrect zone_size as well.
Once the correct zone_size is read from the device, we can rely on the
zoned flag in fs_info as well to determine if the filesystem is zoned.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have no write pointer in conventional zones, we cannot
determine the allocation offset from it. Instead, we set the allocation
offset after the highest addressed extent. This is done by reading the
extent tree in btrfs_load_block_group_zone_info().
However, this function is called from btrfs_read_block_groups(), so the
read lock for the tree node could be recursively taken.
To avoid this unsafe locking scenario, release the path before reading
the extent tree to get the allocation offset.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A zoned filesystem currently has a superblock at the beginning of the
superblock logging zones if the zones are conventional. This difference
in superblock position causes a chicken-and-egg problem for filesystems
with emulated zones. Since the device is a regular (non-zoned) device,
we cannot know if the filesystem is regular or zoned while reading the
superblock. But, to load the superblock, we need to see if it is
emulated zoned or not.
Place the superblocks at the same location as they are on regular
filesystem on regular devices to solve the problem. It is possible
because it's ensured that all the superblock locations are at an
(emulated) conventional zone on regular devices.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a preparation patch to implement zone emulation on a regular
device.
To emulate a zoned filesystem on a regular (non-zoned) device, we need to
decide an emulated zone size. Instead of making it a compile-time static
value, we'll make it configurable at mkfs time. Since we have one zone ==
one device extent restriction, we can determine the emulated zone size
from the size of a device extent. We can extend btrfs_get_dev_zone_info()
to show a regular device filled with conventional zones once the zone size
is decided.
The current call site of btrfs_get_dev_zone_info() during the mount process
is earlier than loading the file system trees so that we don't know the
size of a device extent at this point. Thus we can't slice a regular device
to conventional zones.
This patch introduces btrfs_get_dev_zone_info_all_devices to load the zone
info for all the devices. And, it places this function in open_ctree()
after loading the trees.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_copy_root(), if the call to btrfs_inc_ref() fails we end up
returning without unlocking and releasing our reference on the extent
buffer named "cow" we previously allocated with btrfs_alloc_tree_block().
So fix that by unlocking the extent buffer and dropping our reference on
it before returning.
Fixes: be20aa9dba ("Btrfs: Add mount option to turn off data cow")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In read_extent_buffer_pages(), if we failed to lock the page atomically,
we just exit with return value 0.
This is counter-intuitive, as normally if we can't lock what we need, we
would return something like EAGAIN.
But that return hides under (wait == WAIT_NONE) branch, which only gets
triggered for readahead.
And for readahead, if we failed to lock the page, it means the extent
buffer is either being read by other thread, or has been read and is
under modification. Either way the eb will or has been cached, thus
readahead has no need to wait for it.
Add comment on this counter-intuitive behavior.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This adds the basic RO mount ability for 4K sector size on 64K page
system.
Currently we only plan to support 4K and 64K page system.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs data page read path, the page status update are handled in two
different locations:
btrfs_do_read_page()
{
while (cur <= end) {
/* No need to read from disk */
if (HOLE/PREALLOC/INLINE){
memset();
set_extent_uptodate();
continue;
}
/* Read from disk */
ret = submit_extent_page(end_bio_extent_readpage);
}
end_bio_extent_readpage()
{
endio_readpage_uptodate_page_status();
}
This is fine for sectorsize == PAGE_SIZE case, as for above loop we
should only hit one branch and then exit.
But for subpage, there is more work to be done in page status update:
- Page Unlock condition
Unlike regular page size == sectorsize case, we can no longer just
unlock a page.
Only the last reader of the page can unlock the page.
This means, we can unlock the page either in the while() loop, or in
the endio function.
- Page uptodate condition
Since we have multiple sectors to read for a page, we can only mark
the full page uptodate if all sectors are uptodate.
To handle both subpage and regular cases, introduce a pair of functions
to help handling page status update:
- begin_page_read()
For regular case, it does nothing.
For subpage case, it updates the reader counters so that later
end_page_read() can know who is the last one to unlock the page.
- end_page_read()
This is just endio_readpage_uptodate_page_status() renamed.
The original name is a little too long and too specific for endio.
The new thing added is the condition for page unlock.
Now for subpage data, we unlock the page if we're the last reader.
This does not only provide the basis for subpage data read, but also
hide the special handling of page read from the main read loop.
Also, since we're changing how the page lock is handled, there are two
existing error paths where we need to manually unlock the page before
calling begin_page_read().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To support subpage sector size, data also need extra info to make sure
which sectors in a page are uptodate/dirty/...
This patch will make pages for data inodes get btrfs_subpage structure
attached, and detached when the page is freed.
This patch also slightly changes the timing when
set_page_extent_mapped() is called to make sure:
- We have page->mapping set
page->mapping->host is used to grab btrfs_fs_info, thus we can only
call this function after page is mapped to an inode.
One call site attaches pages to inode manually, thus we have to modify
the timing of set_page_extent_mapped() a bit.
- As soon as possible, before other operations
Since memory allocation can fail, we have to do extra error handling.
Calling set_page_extent_mapped() as soon as possible can simply the
error handling for several call sites.
The idea is pretty much the same as iomap_page, but with more bitmaps
for btrfs specific cases.
Currently the plan is to switch iomap if iomap can provide sector
aligned write back (only write back dirty sectors, but not the full
page, data balance require this feature).
So we will stick to btrfs specific bitmap for now.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For subpage metadata validation check, there are some differences:
- Read must finish in one bvec
Since we're just reading one subpage range in one page, it should
never be split into two bios nor two bvecs.
- How to grab the existing eb
Instead of grabbing eb using page->private, we have to go search radix
tree as we don't have any direct pointer at hand.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To handle subpage status update, add the following:
- Use btrfs_page_*() subpage-aware helpers to update page status
Now we can handle both cases well.
- No page unlock for subpage metadata
Since subpage metadata doesn't utilize page locking at all, skip it.
For subpage data locking, it's handled in later commits.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a helper, read_extent_buffer_subpage(), to do the subpage
extent buffer read.
The difference between regular and subpage routines are:
- No page locking
Here we completely rely on extent locking.
Page locking can reduce the concurrency greatly, as if we lock one
page to read one extent buffer, all the other extent buffers in the
same page will have to wait.
- Extent uptodate condition
Despite the existing PageUptodate() and EXTENT_BUFFER_UPTODATE check,
We also need to check btrfs_subpage::uptodate_bitmap.
- No page iteration
Just one page, no need to loop, this greatly simplified the subpage
routine.
This patch only implements the bio submit part, no endio support yet.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Unlike the original try_release_extent_buffer(),
try_release_subpage_extent_buffer() will iterate through all the ebs in
the page, and try to release each.
We can release the full page only after there's no private attached,
which means all ebs of that page have been released as well.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For btrfs_clone_extent_buffer(), it's mostly the same code of
__alloc_dummy_extent_buffer(), except it has extra page copy.
So to make it subpage compatible, we only need to:
- Call set_extent_buffer_uptodate() instead of SetPageUptodate()
This will set correct uptodate bit for subpage and regular sector size
cases.
Since we're calling set_extent_buffer_uptodate() which will also set
EXTENT_BUFFER_UPTODATE bit, we don't need to manually set that bit
either.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To support subpage in set_extent_buffer_uptodate and
clear_extent_buffer_uptodate we only need to use the subpage-aware
helpers to update the page bits.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce the following functions to handle subpage error status:
- btrfs_subpage_set_error()
- btrfs_subpage_clear_error()
- btrfs_subpage_test_error()
These helpers can only be called when the page has subpage attached
and the range is ensured to be inside the page.
- btrfs_page_set_error()
- btrfs_page_clear_error()
- btrfs_page_test_error()
These helpers can handle both regular sector size and subpage without
problem.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce the following functions to handle subpage uptodate status:
- btrfs_subpage_set_uptodate()
- btrfs_subpage_clear_uptodate()
- btrfs_subpage_test_uptodate()
These helpers can only be called when the page has subpage attached
and the range is ensured to be inside the page.
- btrfs_page_set_uptodate()
- btrfs_page_clear_uptodate()
- btrfs_page_test_uptodate()
These helpers can handle both regular sector size and subpage.
Although caller should still ensure that the range is inside the page.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are locations where we allocate dummy extent buffers for temporary
usage, like in tree_mod_log_rewind() or get_old_root().
These dummy extent buffers will be handled by the same eb accessors, and
if they don't have page::private subpage eb accessors could fail.
To address such problems, make __alloc_dummy_extent_buffer() attach
page private for dummy extent buffers too.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_release_extent_buffer_pages(), we need to add extra handling
for subpage.
Introduce a helper, detach_extent_buffer_page(), to do different
handling for regular and subpage cases.
For subpage case, handle detaching page private.
For unmapped (dummy or cloned) ebs, we can detach the page private
immediately as the page can only be attached to one unmapped eb.
For mapped ebs, we have to ensure there are no eb in the page range
before we delete it, as page->private is shared between all ebs in the
same page.
But there is a subpage specific race, where we can race with extent
buffer allocation, and clear the page private while new eb is still
being utilized, like this:
Extent buffer A is the new extent buffer which will be allocated,
while extent buffer B is the last existing extent buffer of the page.
T1 (eb A) | T2 (eb B)
-------------------------------+------------------------------
alloc_extent_buffer() | btrfs_release_extent_buffer_pages()
|- p = find_or_create_page() | |
|- attach_extent_buffer_page() | |
| | |- detach_extent_buffer_page()
| | |- if (!page_range_has_eb())
| | | No new eb in the page range yet
| | | As new eb A hasn't yet been
| | | inserted into radix tree.
| | |- btrfs_detach_subpage()
| | |- detach_page_private();
|- radix_tree_insert() |
Then we have a metadata eb whose page has no private bit.
To avoid such race, we introduce a subpage metadata-specific member,
btrfs_subpage::eb_refs.
In alloc_extent_buffer() we increase eb_refs in the critical section of
private_lock. Then page_range_has_eb() will return true for
detach_extent_buffer_page(), and will not detach page private.
The section is marked by:
- btrfs_page_inc_eb_refs()
- btrfs_page_dec_eb_refs()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For subpage case, grab_extent_buffer() can't really get an extent buffer
just from btrfs_subpage.
We have radix tree lock protecting us from inserting the same eb into
the tree. Thus we don't really need to do the extra hassle, just let
alloc_extent_buffer() handle the existing eb in radix tree.
Now if two ebs are being allocated as the same time, one will fail with
-EEIXST when inserting into the radix tree.
So for grab_extent_buffer(), just always return NULL for subpage case.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For subpage case, we need to allocate additional memory for each
metadata page.
So we need to:
- Allow attach_extent_buffer_page() to return int to indicate allocation
failure
- Allow manually pre-allocate subpage memory for alloc_extent_buffer()
As we don't want to use GFP_ATOMIC under spinlock, we introduce
btrfs_alloc_subpage() and btrfs_free_subpage() functions for this
purpose.
(The simple wrap for btrfs_free_subpage() is for later convert to
kmem_cache. Already internally tested without problem)
- Preallocate btrfs_subpage structure for alloc_extent_buffer()
We don't want to call memory allocation with spinlock held, so
do preallocation before we acquire mapping->private_lock.
- Handle subpage and regular case differently in
attach_extent_buffer_page()
For regular case, no change, just do the usual thing.
For subpage case, allocate new memory or use the preallocated memory.
For future subpage metadata, we will make use of radix tree to grab
extent buffer.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For sectorsize < page size support, we need a structure to record extra
status info for each sector of a page.
Introduce the skeleton structure, all subpage related code would go to
subpage.[ch].
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For the incoming subpage support, UNMAPPED extent buffer will have
different behavior in btrfs_release_extent_buffer().
This means we need to set UNMAPPED bit early before calling
btrfs_release_extent_buffer().
Currently there is only one caller which relies on
btrfs_release_extent_buffer() in its error path while set UNMAPPED bit
late:
- btrfs_clone_extent_buffer()
Make it subpage compatible by setting the UNMAPPED bit early, since
we're here, also move the UPTODATE bit early.
There is another caller, __alloc_dummy_extent_buffer(), setting
UNMAPPED bit late, but that function clean up the allocated page
manually, thus no need for any modification.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
PAGE_CLEAR_DIRTY and PAGE_SET_WRITEBACK are two defines used in
__process_pages_contig(), to let the function know to clear page dirty
bit and then set page writeback.
However page writeback and dirty bits are conflicting (at least for
sector size == PAGE_SIZE case), this means these two have to be always
updated together.
This means we can merge PAGE_CLEAR_DIRTY and PAGE_SET_WRITEBACK to
PAGE_START_WRITEBACK.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Often an fsync needs to fallback to a transaction commit for several
reasons (to ensure consistency after a power failure, a new block group
was allocated or a temporary error such as ENOMEM or ENOSPC happened).
In that case the log is marked as needing a full commit and any concurrent
tasks attempting to log inodes or commit the log will also fallback to the
transaction commit. When this happens they all wait for the task that first
started the transaction commit to finish the transaction commit - however
they wait until the full transaction commit happens, which is not needed,
as they only need to wait for the superblocks to be persisted and not for
unpinning all the extents pinned during the transaction's lifetime, which
even for short lived transactions can be a few thousand and take some
significant amount of time to complete - for dbench workloads I have
observed up to 4~5 milliseconds of time spent unpinning extents in the
worst cases, and the number of pinned extents was between 2 to 3 thousand.
So allow fsync tasks to skip waiting for the unpinning of extents when
they call btrfs_commit_transaction() and they were not the task that
started the transaction commit (that one has to do it, the alternative
would be to offload the transaction commit to another task so that it
could avoid waiting for the extent unpinning or offload the extent
unpinning to another task).
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
After applying the entire patchset, dbench shows improvements in respect
to throughput and latency. The script used to measure it is the following:
$ cat dbench-test.sh
#!/bin/bash
DEV=/dev/sdk
MNT=/mnt/sdk
MOUNT_OPTIONS="-o ssd"
MKFS_OPTIONS="-m single -d single"
echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
umount $DEV &> /dev/null
mkfs.btrfs -f $MKFS_OPTIONS $DEV
mount $MOUNT_OPTIONS $DEV $MNT
dbench -D $MNT -t 300 64
umount $MNT
The test was run on a physical machine with 12 cores (Intel corei7), 64G
of ram, using a NVMe device and a non-debug kernel configuration (Debian's
default configuration).
Before applying patchset, 32 clients:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 9627107 0.153 61.938
Close 7072076 0.001 3.175
Rename 407633 1.222 44.439
Unlink 1943895 0.658 44.440
Deltree 256 17.339 110.891
Mkdir 128 0.003 0.009
Qpathinfo 8725406 0.064 17.850
Qfileinfo 1529516 0.001 2.188
Qfsinfo 1599884 0.002 1.457
Sfileinfo 784200 0.005 3.562
Find 3373513 0.411 30.312
WriteX 4802132 0.053 29.054
ReadX 15089959 0.002 5.801
LockX 31344 0.002 0.425
UnlockX 31344 0.001 0.173
Flush 674724 5.952 341.830
Throughput 1008.02 MB/sec 32 clients 32 procs max_latency=341.833 ms
After applying patchset, 32 clients:
After patchset, with 32 clients:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 9931568 0.111 25.597
Close 7295730 0.001 2.171
Rename 420549 0.982 49.714
Unlink 2005366 0.497 39.015
Deltree 256 11.149 89.242
Mkdir 128 0.002 0.014
Qpathinfo 9001863 0.049 20.761
Qfileinfo 1577730 0.001 2.546
Qfsinfo 1650508 0.002 3.531
Sfileinfo 809031 0.005 5.846
Find 3480259 0.309 23.977
WriteX 4952505 0.043 41.283
ReadX 15568127 0.002 5.476
LockX 32338 0.002 0.978
UnlockX 32338 0.001 2.032
Flush 696017 7.485 228.835
Throughput 1049.91 MB/sec 32 clients 32 procs max_latency=228.847 ms
--> +4.1% throughput, -39.6% max latency
Before applying patchset, 64 clients:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 8956748 0.342 108.312
Close 6579660 0.001 3.823
Rename 379209 2.396 81.897
Unlink 1808625 1.108 131.148
Deltree 256 25.632 172.176
Mkdir 128 0.003 0.018
Qpathinfo 8117615 0.131 55.916
Qfileinfo 1423495 0.001 2.635
Qfsinfo 1488496 0.002 5.412
Sfileinfo 729472 0.007 8.643
Find 3138598 0.855 78.321
WriteX 4470783 0.102 79.442
ReadX 14038139 0.002 7.578
LockX 29158 0.002 0.844
UnlockX 29158 0.001 0.567
Flush 627746 14.168 506.151
Throughput 924.738 MB/sec 64 clients 64 procs max_latency=506.154 ms
After applying patchset, 64 clients:
Operation Count AvgLat MaxLat
----------------------------------------
NTCreateX 9069003 0.303 43.193
Close 6662328 0.001 3.888
Rename 383976 2.194 46.418
Unlink 1831080 1.022 43.873
Deltree 256 24.037 155.763
Mkdir 128 0.002 0.005
Qpathinfo 8219173 0.137 30.233
Qfileinfo 1441203 0.001 3.204
Qfsinfo 1507092 0.002 4.055
Sfileinfo 738775 0.006 5.431
Find 3177874 0.936 38.170
WriteX 4526152 0.084 39.518
ReadX 14213562 0.002 24.760
LockX 29522 0.002 1.221
UnlockX 29522 0.001 0.694
Flush 635652 14.358 422.039
Throughput 990.13 MB/sec 64 clients 64 procs max_latency=422.043 ms
--> +6.8% throughput, -18.1% max latency
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we fsync an inode, if it is a directory, a regular file that was
created in the current transaction or has last_unlink_trans set to the
generation of the current transaction, we check if any of its ancestor
inodes (and the inode itself if it is a directory) can not be logged and
need a fallback to a full transaction commit - if so, we return with a
value of 1 in order to fallback to a transaction commit.
However we often do not need to fallback to a transaction commit because:
1) The ancestor inode is not an immediate parent, and therefore there is
not an explicit request to log it and it is not needed neither to
guarantee the consistency of the inode originally asked to be logged
(fsynced) nor its immediate parent;
2) The ancestor inode was already logged before, in which case any link,
unlink or rename operation updates the log as needed.
So for these two cases we can avoid an unnecessary transaction commit.
Therefore remove check_parent_dirs_for_sync() and add a check at the top
of btrfs_log_inode() to make us fallback immediately to a transaction
commit when we are logging a directory inode that can not be logged and
needs a full transaction commit. All we need to protect is the case where
after renaming a file someone fsyncs only the old directory, which would
result is losing the renamed file after a log replay.
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When logging new directory entries of a directory, we log the inodes of
new dentries and the inodes of dentries pointing to directories that
may have been created in past transactions. For the case of directories
we log in full mode, which can be particularly expensive for large
directories.
We do use btrfs_inode_in_log() to skip already logged inodes, however for
that helper to return true, it requires that the log transaction used to
log the inode to be already committed. This means that when we have more
than one task using the same log transaction we can end up logging an
inode multiple times, which is a waste of time and not necessary since
the log will be committed by one of the tasks and the others will wait for
the log transaction to be committed before returning to user space.
So simply replace the use of btrfs_inode_in_log() with the new helper
function need_log_inode(), introduced in a previous commit.
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Some times when we fsync an inode we need to do a full log of all its
ancestors (due to unlink, link or rename operations), which can be an
expensive operation, specially if the directories are large.
However if we find an ancestor directory inode that is already logged in
the current transaction, and has no inserted/updated/deleted xattrs since
it was last logged, we can skip logging the directory again. We are safe
to skip that since we know that for logged directories, any link, unlink
or rename operations that implicate the directory will update the log as
necessary.
So use the helper need_log_dir(), introduced in a previous commit, to
detect already logged directories that can be skipped.
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we fsync a new file, created in the current transaction, we check
all its ancestor inodes and always log them if they were created in the
current transaction - even if we have already logged them before, which
is a waste of time.
So avoid logging new ancestor inodes if they were already logged before
and have no xattrs added/updated/removed since they were last logged.
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we fill an inode item for logging we are setting its nbytes field
with the value returned by inode_get_bytes() (a VFS API), however we do
not need it because it is not used during log replay. In fact, for fast
fsyncs, when we call inode_get_bytes() we may even get an outdated value
for nbytes because the nbytes field of the inode is only updated when
ordered extents complete, and a fast fsync only waits for writeback to
complete, it does not wait for ordered extent completion.
So just remove the setup of nbytes and add an explicit comment mentioning
why we do not set it. This also avoids adding contention on the inode's
i_lock (VFS) with concurrent stat() calls, since that spinlock is used by
inode_get_bytes() which is also called by our stat callback
(btrfs_getattr()).
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we remove a directory entry, as part of an unlink operation, if the
directory was logged before we must remove the directory index items from
the log. We are also updating the inode item of the directory to update
its i_size, but that is not necessary because during log replay we do not
need it and we correctly adjust the i_size in the inode item of the
subvolume as we process directory index items and replay deletes.
This is not needed since commit d555438b6e ("Btrfs: drop dir i_size
when adding new names on replay"), where we explicitly ignore the i_size
of directory inode items on log replay. Before that we used it but it
was buggy as mentioned in that commit's change log (i_size got a larger
value then it should have).
So stop updating the i_size of the directory inode item in the log, as
that is a waste of time, adds more log contention to the log tree and
often results in COWing more extent buffers for the log tree.
This code path is triggered often during dbench workloads for example.
This patch is part of a patchset comprised of the following patches:
btrfs: remove unnecessary directory inode item update when deleting dir entry
btrfs: stop setting nbytes when filling inode item for logging
btrfs: avoid logging new ancestor inodes when logging new inode
btrfs: skip logging directories already logged when logging all parents
btrfs: skip logging inodes already logged when logging new entries
btrfs: remove unnecessary check_parent_dirs_for_sync()
btrfs: make concurrent fsyncs wait less when waiting for a transaction commit
Performance results, after applying all patches, are mentioned in the
change log of the last patch.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before this change, the btrfs_get_io_geometry() function was calling
btrfs_get_chunk_map() to get the extent mapping, necessary for
calculating the I/O geometry. It was using that extent mapping only
internally and freeing the pointer after its execution.
That resulted in calling btrfs_get_chunk_map() de facto twice by the
__btrfs_map_block() function. It was calling btrfs_get_io_geometry()
first and then calling btrfs_get_chunk_map() directly to get the extent
mapping, used by the rest of the function.
Change that to passing the extent mapping to the btrfs_get_io_geometry()
function as an argument.
This could improve performance in some cases. For very large
filesystems, i.e. several thousands of allocated chunks, not only this
avoids searching two times the rbtree, saving time, it may also help
reducing contention on the lock that protects the tree - thinking of
writeback starting for multiple inodes, other tasks allocating or
removing chunks, and anything else that requires access to the rbtree.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Michal Rostecki <mrostecki@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add Filipe's analysis ]
Signed-off-by: David Sterba <dsterba@suse.com>
Commit dbfdb6d1b3 ("Btrfs: Search for all ordered extents that could
span across a page") make btrfs_invalidapage() to search all ordered
extents.
The offending code looks like this:
again:
start = page_start;
ordered = btrfs_lookup_ordered_range(inode, start, page_end - start + 1);
if (ordred) {
end = min(page_end,
ordered->file_offset + ordered->num_bytes - 1);
/* Do the cleanup */
start = end + 1;
if (start < page_end)
goto again;
}
The behavior is indeed necessary for the incoming subpage support, but
when it iterates through all the ordered extents, it also resets the
search range @start.
This means, for the following cases, we can double account the ordered
extents, causing its bytes_left underflow:
Page offset
0 16K 32K
|<--- OE 1 --->|<--- OE 2 ---->|
As the first iteration will find ordered extent (OE) 1, which doesn't
cover the full page, thus after cleanup code, we need to retry again.
But again label will reset start to page_start, and we got OE 1 again,
which causes double accounting on OE 1, and cause OE 1's byte_left to
underflow.
This problem can only happen for subpage case, as for regular sectorsize
== PAGE_SIZE case, we will always find a OE ends at or after page end,
thus no way to trigger the problem.
Move the again label after start = page_start. There will be more
comprehensive rework to convert the open coded loop to a proper while
loop for subpage support.
Fixes: dbfdb6d1b3 ("Btrfs: Search for all ordered extents that could span across a page")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix the following coccicheck warnings:
./fs/btrfs/delayed-inode.c:1157:39-41: WARNING !A || A && B is
equivalent to !A || B.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Suggested-by: Jiapeng Zhong <oswb@linux.alibaba.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Abaci Team <abaci-bugfix@linux.alibaba.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The comment for can_nocow_extent() says that the function will flush
ordered extents, however that never happens and was never true before the
comment was added in commit e4ecaf90bc ("btrfs: add comments for
btrfs_check_can_nocow() and can_nocow_extent()"). This is true only for
the function btrfs_check_can_nocow(), which after that commit was renamed
to check_can_nocow(). So just remove that part of the comment.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Often when I'm debugging ENOSPC related issues I have to resort to
printing the entire ENOSPC state with trace_printk() in different spots.
This gets pretty annoying, so add a trace state that does this for us.
Then add a trace point at the end of preemptive flushing so you can see
the state of the space_info when we decide to exit preemptive flushing.
This helped me figure out we weren't kicking in the preemptive flushing
soon enough.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have normal ticketed flushing and preemptive flushing, adjust
the tracepoint so that we know the source of the flushing action to make
it easier to debug problems.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Starting preemptive flushing at 50% of available free space is a good
start, but some workloads are particularly abusive and can quickly
overwhelm the preemptive flushing code and drive us into using tickets.
Handle this by clamping down on our threshold for starting and
continuing to run preemptive flushing. This is particularly important
for our overcommit case, as we can really drive the file system into
overages and then it's more difficult to pull it back as we start to
actually fill up the file system.
The clamping is essentially 2^CLAMP, but we start at 1 so whatever we
calculate for overcommit is the baseline.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A lot of this was added all in one go with no explanation, and is a bit
unwieldy and confusing. Simplify the logic to start preemptive flushing
if we've reserved more than half of our available free space.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_calc_reclaim_metadata_size does two things, it returns
the space currently required for flushing by the tickets, and if there
are no tickets it calculates a value for the preemptive flushing.
However for the normal ticketed flushing we really only care about the
space required for tickets. We will accidentally come in and flush one
time, but as soon as we see there are no tickets we bail out of our
flushing.
Fix this by making btrfs_calc_reclaim_metadata_size really only tell us
what is required for flushing if we have people waiting on space. Then
move the preemptive flushing logic into need_preemptive_reclaim(). We
ignore btrfs_calc_reclaim_metadata_size() in need_preemptive_reclaim()
because if we are in this path then we made our reservation and there
are not pending tickets currently, so we do not need to check it, simply
do the fuzzy logic to check if we're getting low on space.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we're flushing space for tickets then we have
space_info->reclaim_size set and we do not need to do background
reclaim.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All of our normal flushing is asynchronous reclaim, so this helper is
poorly named. This is more checking if we need to preemptively flush
space, so rename it to need_preemptive_reclaim.
Also switch it to bool and make it plain static as followup patches will
move more code here.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently if we ever have to flush space because we do not have enough
we allocate a ticket and attach it to the space_info, and then
systematically flush things in the filesystem that hold space
reservations until our space is reclaimed.
However this has a latency cost, we must go to sleep and wait for the
flushing to make progress before we are woken up and allowed to continue
doing our work.
In order to address that we used to kick off the async worker to flush
space preemptively, so that we could be reclaiming space hopefully
before any tasks needed to stop and wait for space to reclaim.
When I introduced the ticketed ENOSPC stuff this broke slightly in the
fact that we were using tickets to indicate if we were done flushing.
No tickets, no more flushing. However this meant that we essentially
never preemptively flushed. This caused a write performance regression
that Nikolay noticed in an unrelated patch that removed the committing
of the transaction during btrfs_end_transaction.
The behavior that happened pre that patch was btrfs_end_transaction()
would see that we were low on space, and it would commit the
transaction. This was bad because in this particular case you could end
up with thousands and thousands of transactions being committed during
the 5 minute reproducer. With the patch to remove this behavior we got
much more sane transaction commits, but we ended up slower because we
would write for a while, flush, write for a while, flush again.
To address this we need to reinstate a preemptive flushing mechanism.
However it is distinctly different from our ticketing flushing in that
it doesn't have tickets to base it's decisions on. Instead of bolting
this logic into our existing flushing work, add another worker to handle
this preemptive flushing. Here we will attempt to be slightly
intelligent about the things that we flushing, attempting to balance
between whichever pool is taking up the most space.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Solely for preemptive flushing, we want to be able to force the
transaction commit without any of the ambiguity of
may_commit_transaction(). This is because may_commit_transaction()
checks tickets and such, and in preemptive flushing we already know
it'll be helpful, so use this to keep the code nice and clean and
straightforward.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
We track dio_bytes because the shrink delalloc code needs to know if we
have more DIO in flight than we have normal buffered IO. The reason for
this is because we can't "flush" DIO, we have to just wait on the
ordered extents to finish.
However this is true of all ordered extents. If we have more ordered
space outstanding than dirty pages we should be waiting on ordered
extents. We already are ok on this front technically, because we always
do a FLUSH_DELALLOC_WAIT loop, but I want to use the ordered counter in
the preemptive flushing code as well, so change this to count all
ordered bytes instead of just DIO ordered bytes.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While debugging a ENOSPC related performance problem I needed to see the
time difference between start and end of a reserve ticket, so add a
trace point to report when we handle a reserve ticket.
I opted to spit out start_ns itself without calculating the difference
because there could be a gap between enabling the tracepoint and setting
start_ns. Doing it this way allows us to filter on 0 start_ns so we
don't get bogus entries, and we can easily calculate the time difference
with bpftrace or something else.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I got a automated message from somebody who runs clang against our
kernels and it's because I used the wrong enum type for what I passed
into flush_space, caught by -Wenum-conversion. Change the argument to
be explicitly the enum we're expecting to make everything consistent.
Maybe eventually gcc will catch errors like this.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_compare_trees and changed_cb use a void *ctx parameter instead of
struct send_ctx *sctx but when used in changed_cb it is immediately
cast to `struct send_ctx *sctx = ctx;`.
changed_cb is only ever called from btrfs_compare_trees and full_send_tree:
- full_send_tree already passes a struct send_ctx *sctx
- btrfs_compare_trees is only called by send_subvol with a struct send_ctx *sctx
- void *ctx in btrfs_compare_trees is only used to be passed to changed_cb
So casting to/from void *ctx seems unnecessary and directly using
struct send_ctx *sctx instead provides better type-safety.
The original reason for using void *ctx in the first place seems to have
been dropped with 1b51d6fce4 ("btrfs: send: remove indirect callback
parameter for changed_cb").
Signed-off-by: Roman Anasal <roman.anasal@bdsu.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We love running delayed refs in commit_cowonly_roots, but it is a bit
excessive. I was seeing cases of running 3 or 4 refs a few times in a
row during this time. Instead simply:
- update all of the roots first
- then run delayed refs
- then handle the empty block groups case
- and then if we have any more dirty roots do the whole thing again
This allows us to be much more efficient with our delayed ref running,
as we can batch a few more operations at once.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This was added in commit 361048f586 ("Btrfs: fix full backref problem
when inserting shared block reference") to address a problem where we
hit the following BUG_ON() in alloc_reserved_tree_block
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
However this BUG_ON() is bogus, and was removed by previous commit:
btrfs: remove bogus BUG_ON in alloc_reserved_tree_block
We no longer need to run delayed refs because of this, and can remove
this flushing here.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The fix 361048f586 ("Btrfs: fix full backref problem when inserting
shared block reference") added a delayed ref flushing at subvolume
creation time in order to avoid hitting this particular BUG_ON().
Before this fix, we were tripping the BUG_ON() by
1. Modify snapshot A, which creates blocks with a normal reference for
snapshot A, as A is the owner of these blocks. We now have delayed
refs for these blocks.
2. Create a snapshot of A named B, which pushes references for the
children blocks of the root node for the new root B, thus creating
more delayed refs for newly allocated blocks.
3. A is modified, and because the metadata blocks can now be shared, it
must push FULL_BACKREF references to the children of any block that A
COWs down it's path to its target key.
4. Delayed refs are run. Because these are newly allocated blocks, we
have ->must_insert_reserved reserved set on the delayed ref head, we
call into alloc_reserved_tree_block() to add the extent item, and
then add our ref. At the time of this fix, we were ordering
FULL_BACKREF delayed ref operations first, so we'd go to add this
reference and then BUG_ON() because we didn't have the FULL_BACKREF
flag set.
The patch fixed this problem by making sure we ran the delayed refs
before we had the chance to modify A. This meant that any *new* blocks
would have had their extent items created _before_ we would ever
actually COW down and generate FULL_BACKREF entries. Thus the problem
went away.
However this BUG_ON() is actually completely bogus. The existence of a
full backref doesn't necessarily mean that FULL_BACKREF must be set on
that block, it must only be set on the actual parent itself. Consider
the example provided above. If we COW down one path from A, any nodes
are going to have a FULL_BACKREF ref pushed down to _all_ of their
children, but not all of the children are going to have FULL_BACKREF
set. It is completely valid to have an extent item with normal and full
backrefs without FULL_BACKREF actually set on the block itself.
As a final note, I have been testing with the patch (applied after this
one)
btrfs: stop running all delayed refs during snapshot
which removed this flushing. My test was a torture test which did a lot
of operations while snapshotting and deleting snapshots as well as
relocation, and I never tripped this BUG_ON(). This is actually because
at the time of 361048f586, we ordered SHARED keys _before_ normal
references, and thus they would get run first. However currently they
are ordered _after_ normal references, so we'd do the initial creation
without having a shared reference, and thus not hit this BUG_ON(), which
explains why I didn't start hitting this problem during my testing with
my other patch applied.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The commit d672633545 ("btrfs: qgroup: Make snapshot accounting work
with new extent-oriented qgroup.") added a flush of the delayed refs
during snapshot creation in order to get the qgroup accounting properly.
However this code has changed and been moved to it's own helper that is
skipped if qgroups are turned off. Move the flushing to the helper, as
we do not need it when qgroups are turned off.
Also add a comment explaining why it exists, and why it doesn't actually
save us. This will be helpful later when we try to fix qgroup
accounting properly.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We try to pre-flush the delayed refs when committing, because we want to
do as little work as possible in the critical section of the transaction
commit.
However doing this twice can lead to very long transaction commit delays
as other threads are allowed to continue to generate more delayed refs,
which potentially delays the commit by multiple minutes in very extreme
cases.
So simply stick to one pre-flush, and then continue the rest of the
transaction commit.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Previously our delayed ref running used the total number of items as the
items to run. However we changed that to number of heads to run with
the delayed_refs_rsv, as generally we want to run all of the operations
for one bytenr.
But with btrfs_run_delayed_refs(trans, 0) we set our count to 2x the
number of items that we have. This is generally fine, but if we have
some operation generation loads of delayed refs while we're doing this
pre-flushing in the transaction commit, we'll just spin forever doing
delayed refs.
Fix this to simply pick the number of delayed refs we currently have,
that way we do not end up doing a lot of extra work that's being
generated in other threads.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I've been running a stress test that runs 20 workers in their own
subvolume, which are running an fsstress instance with 4 threads per
worker, which is 80 total fsstress threads. In addition to this I'm
running balance in the background as well as creating and deleting
snapshots. This test takes around 12 hours to run normally, going
slower and slower as the test goes on.
The reason for this is because fsstress is running fsync sometimes, and
because we're messing with block groups we often fall through to
btrfs_commit_transaction, so will often have 20-30 threads all calling
btrfs_commit_transaction at the same time.
These all get stuck contending on the extent tree while they try to run
delayed refs during the initial part of the commit.
This is suboptimal, really because the extent tree is a single point of
failure we only want one thread acting on that tree at once to reduce
lock contention.
Fix this by making the flushing mechanism a bit operation, to make it
easy to use test_and_set_bit() in order to make sure only one task does
this initial flush.
Once we're into the transaction commit we only have one thread doing
delayed ref running, it's just this initial pre-flush that is
problematic. With this patch my stress test takes around 90 minutes to
run, instead of 12 hours.
The memory barrier is not necessary for the flushing bit as it's
ordered, unlike plain int. The transaction state accessed in
btrfs_should_end_transaction could be affected by that too as it's not
always used under transaction lock. Upon Nikolay's analysis in [1]
it's not necessary:
In should_end_transaction it's read without holding any locks. (U)
It's modified in btrfs_cleanup_transaction without holding the
fs_info->trans_lock (U), but the STATE_ERROR flag is going to be set.
set in cleanup_transaction under fs_info->trans_lock (L)
set in btrfs_commit_trans to COMMIT_START under fs_info->trans_lock.(L)
set in btrfs_commit_trans to COMMIT_DOING under fs_info->trans_lock.(L)
set in btrfs_commit_trans to COMMIT_UNBLOCK under
fs_info->trans_lock.(L)
set in btrfs_commit_trans to COMMIT_COMPLETED without locks but at this
point the transaction is finished and fs_info->running_trans is NULL (U
but irrelevant).
So by the looks of it we can have a concurrent READ race with a WRITE,
due to reads not taking a lock. In this case what we want to ensure is
we either see new or old state. I consulted with Will Deacon and he said
that in such a case we'd want to annotate the accesses to ->state with
(READ|WRITE)_ONCE so as to avoid a theoretical tear, in this case I
don't think this could happen but I imagine at some point KCSAN would
flag such an access as racy (which it is).
[1] https://lore.kernel.org/linux-btrfs/e1fd5cc1-0f28-f670-69f4-e9958b4964e6@suse.com
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add comments regarding memory barrier ]
Signed-off-by: David Sterba <dsterba@suse.com>
While running some stress tests I started getting hung task messages.
This is because the delete unused block groups code has to take the
delete_unused_bgs_mutex to do it's work, which is taken by balance to
make sure we don't delete block groups while we're balancing.
The problem is that balance can take a while, and so we were getting
hung task warnings. We don't need to block and run these things, and
the cleaner is needed to do other work, so trylock on this mutex and
just bail if we can't acquire it right away.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While testing my error handling patches, I added a error injection site
at btrfs_inc_extent_ref, to validate the error handling I added was
doing the correct thing. However I hit a pretty ugly corruption while
doing this check, with the following error injection stack trace:
btrfs_inc_extent_ref
btrfs_copy_root
create_reloc_root
btrfs_init_reloc_root
btrfs_record_root_in_trans
btrfs_start_transaction
btrfs_update_inode
btrfs_update_time
touch_atime
file_accessed
btrfs_file_mmap
This is because we do not catch the error from btrfs_inc_extent_ref,
which in practice would be ENOMEM, which means we lose the extent
references for a root that has already been allocated and inserted,
which is the problem. Fix this by aborting the transaction if we fail
to do the reference modification.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A weird KASAN problem that Zygo reported could have been easily caught
if we checked for basic things in our backref freeing code. We have two
methods of freeing a backref node
- btrfs_backref_free_node: this just is kfree() essentially.
- btrfs_backref_drop_node: this actually unlinks the node and cleans up
everything and then calls btrfs_backref_free_node().
We should mostly be using btrfs_backref_drop_node(), to make sure the
node is properly unlinked from the backref cache, and only use
btrfs_backref_free_node() when we know the node isn't actually linked to
the backref cache. We made a mistake here and thus got the KASAN splat.
Make this style of issue easier to find by adding some ASSERT()'s to
btrfs_backref_free_node() and adjusting our deletion stuff to properly
init the list so we can rely on list_empty() checks working properly.
BUG: KASAN: use-after-free in btrfs_backref_cleanup_node+0x18a/0x420
Read of size 8 at addr ffff888112402950 by task btrfs/28836
CPU: 0 PID: 28836 Comm: btrfs Tainted: G W 5.10.0-e35f27394290-for-next+ #23
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack+0xbc/0xf9
? btrfs_backref_cleanup_node+0x18a/0x420
print_address_description.constprop.8+0x21/0x210
? record_print_text.cold.34+0x11/0x11
? btrfs_backref_cleanup_node+0x18a/0x420
? btrfs_backref_cleanup_node+0x18a/0x420
kasan_report.cold.10+0x20/0x37
? btrfs_backref_cleanup_node+0x18a/0x420
__asan_load8+0x69/0x90
btrfs_backref_cleanup_node+0x18a/0x420
btrfs_backref_release_cache+0x83/0x1b0
relocate_block_group+0x394/0x780
? merge_reloc_roots+0x4a0/0x4a0
btrfs_relocate_block_group+0x26e/0x4c0
btrfs_relocate_chunk+0x52/0x120
btrfs_balance+0xe2e/0x1900
? check_flags.part.50+0x6c/0x1e0
? btrfs_relocate_chunk+0x120/0x120
? kmem_cache_alloc_trace+0xa06/0xcb0
? _copy_from_user+0x83/0xc0
btrfs_ioctl_balance+0x3a7/0x460
btrfs_ioctl+0x24c8/0x4360
? __kasan_check_read+0x11/0x20
? check_chain_key+0x1f4/0x2f0
? __asan_loadN+0xf/0x20
? btrfs_ioctl_get_supported_features+0x30/0x30
? kvm_sched_clock_read+0x18/0x30
? check_chain_key+0x1f4/0x2f0
? lock_downgrade+0x3f0/0x3f0
? handle_mm_fault+0xad6/0x2150
? do_vfs_ioctl+0xfc/0x9d0
? ioctl_file_clone+0xe0/0xe0
? check_flags.part.50+0x6c/0x1e0
? check_flags.part.50+0x6c/0x1e0
? check_flags+0x26/0x30
? lock_is_held_type+0xc3/0xf0
? syscall_enter_from_user_mode+0x1b/0x60
? do_syscall_64+0x13/0x80
? rcu_read_lock_sched_held+0xa1/0xd0
? __kasan_check_read+0x11/0x20
? __fget_light+0xae/0x110
__x64_sys_ioctl+0xc3/0x100
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4c4bdfe427
RSP: 002b:00007fff33ee6df8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff33ee6e98 RCX: 00007f4c4bdfe427
RDX: 00007fff33ee6e98 RSI: 00000000c4009420 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000078
R10: fffffffffffff59d R11: 0000000000000202 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fff33ee8a34 R15: 0000000000000001
Allocated by task 28836:
kasan_save_stack+0x21/0x50
__kasan_kmalloc.constprop.18+0xbe/0xd0
kasan_kmalloc+0x9/0x10
kmem_cache_alloc_trace+0x410/0xcb0
btrfs_backref_alloc_node+0x46/0xf0
btrfs_backref_add_tree_node+0x60d/0x11d0
build_backref_tree+0xc5/0x700
relocate_tree_blocks+0x2be/0xb90
relocate_block_group+0x2eb/0x780
btrfs_relocate_block_group+0x26e/0x4c0
btrfs_relocate_chunk+0x52/0x120
btrfs_balance+0xe2e/0x1900
btrfs_ioctl_balance+0x3a7/0x460
btrfs_ioctl+0x24c8/0x4360
__x64_sys_ioctl+0xc3/0x100
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 28836:
kasan_save_stack+0x21/0x50
kasan_set_track+0x20/0x30
kasan_set_free_info+0x1f/0x30
__kasan_slab_free+0xf3/0x140
kasan_slab_free+0xe/0x10
kfree+0xde/0x200
btrfs_backref_error_cleanup+0x452/0x530
build_backref_tree+0x1a5/0x700
relocate_tree_blocks+0x2be/0xb90
relocate_block_group+0x2eb/0x780
btrfs_relocate_block_group+0x26e/0x4c0
btrfs_relocate_chunk+0x52/0x120
btrfs_balance+0xe2e/0x1900
btrfs_ioctl_balance+0x3a7/0x460
btrfs_ioctl+0x24c8/0x4360
__x64_sys_ioctl+0xc3/0x100
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff888112402900
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 80 bytes inside of
128-byte region [ffff888112402900, ffff888112402980)
The buggy address belongs to the page:
page:0000000028b1cd08 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888131c810c0 pfn:0x112402
flags: 0x17ffe0000000200(slab)
raw: 017ffe0000000200 ffffea000424f308 ffffea0007d572c8 ffff888100040440
raw: ffff888131c810c0 ffff888112402000 0000000100000009 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888112402800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888112402880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888112402900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888112402980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888112402a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Link: https://lore.kernel.org/linux-btrfs/20201208194607.GI31381@hungrycats.org/
CC: stable@vger.kernel.org # 5.10+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The backref code is looking for a reloc_root that corresponds to the
given fs root. However any number of things could have gone wrong while
initializing that reloc_root, like ENOMEM while trying to allocate the
root itself, or EIO while trying to write the root item. This would
result in no corresponding reloc_root being in the reloc root cache, and
thus would return NULL when we do the find_reloc_root() call.
Because of this we do not want to WARN_ON(). This presumably was meant
to catch developer errors, cases where we messed up adding the reloc
root. However we can easily hit this case with error injection, and
thus should not do a WARN_ON().
CC: stable@vger.kernel.org # 5.10+
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While doing error injection testing with my relocation patches I hit the
following assert:
assertion failed: list_empty(&block_group->dirty_list), in fs/btrfs/block-group.c:3356
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.h:3357!
invalid opcode: 0000 [#1] SMP NOPTI
CPU: 0 PID: 24351 Comm: umount Tainted: G W 5.10.0-rc3+ #193
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
RIP: 0010:assertfail.constprop.0+0x18/0x1a
RSP: 0018:ffffa09b019c7e00 EFLAGS: 00010282
RAX: 0000000000000056 RBX: ffff8f6492c18000 RCX: 0000000000000000
RDX: ffff8f64fbc27c60 RSI: ffff8f64fbc19050 RDI: ffff8f64fbc19050
RBP: ffff8f6483bbdc00 R08: 0000000000000000 R09: 0000000000000000
R10: ffffa09b019c7c38 R11: ffffffff85d70928 R12: ffff8f6492c18100
R13: ffff8f6492c18148 R14: ffff8f6483bbdd70 R15: dead000000000100
FS: 00007fbfda4cdc40(0000) GS:ffff8f64fbc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbfda666fd0 CR3: 000000013cf66002 CR4: 0000000000370ef0
Call Trace:
btrfs_free_block_groups.cold+0x55/0x55
close_ctree+0x2c5/0x306
? fsnotify_destroy_marks+0x14/0x100
generic_shutdown_super+0x6c/0x100
kill_anon_super+0x14/0x30
btrfs_kill_super+0x12/0x20
deactivate_locked_super+0x36/0xa0
cleanup_mnt+0x12d/0x190
task_work_run+0x5c/0xa0
exit_to_user_mode_prepare+0x1b1/0x1d0
syscall_exit_to_user_mode+0x54/0x280
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This happened because I injected an error in btrfs_cow_block() while
running the dirty block groups. When we run the dirty block groups, we
splice the list onto a local list to process. However if an error
occurs, we only cleanup the transactions dirty block group list, not any
pending block groups we have on our locally spliced list.
In fact if we fail to allocate a path in this function we'll also fail
to clean up the splice list.
Fix this by splicing the list back onto the transaction dirty block
group list so that the block groups are cleaned up. Then add a 'out'
label and have the error conditions jump to out so that the errors are
handled properly. This also has the side-effect of fixing a problem
where we would clear 'ret' on error because we unconditionally ran
btrfs_run_delayed_refs().
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When recovering a relocation, if we run into a reloc root that has 0
refs we simply add it to the reloc_control->reloc_roots list, and then
clean it up later. The problem with this is __del_reloc_root() doesn't
do anything if the root isn't in the radix tree, which in this case it
won't be because we never call __add_reloc_root() on the reloc_root.
This exit condition simply isn't correct really. During normal
operation we can remove ourselves from the rb tree and then we're meant
to clean up later at merge_reloc_roots() time, and this happens
correctly. During recovery we're depending on free_reloc_roots() to
drop our references, but we're short-circuiting.
Fix this by continuing to check if we're on the list and dropping
ourselves from the reloc_control root list and dropping our reference
appropriately. Change the corresponding BUG_ON() to an ASSERT() that
does the correct thing if we aren't in the rb tree.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Comment for processed extent end of range has an unnecessary "in",
remove it.
Signed-off-by: Nigel Christian <nigel.l.christian@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
My recent patch set "A variety of lock contention fixes", found here
https://lore.kernel.org/linux-btrfs/cover.1608319304.git.josef@toxicpanda.com/
(Tracked in https://github.com/btrfs/linux/issues/86)
that reduce lock contention on the extent root by running delayed refs
less often resulted in a regression in generic/371. This test
fallocate()'s the fs until it's full, deletes all the files, and then
tries to fallocate() until full again.
Before these patches we would run all of the delayed refs during
flushing, and then would commit the transaction because we had plenty of
pinned space to recover in order to allocate. However my patches made
it so we weren't running the delayed refs as aggressively, which meant
that we appeared to have less pinned space when we were deciding to
commit the transaction.
We use the space_info->total_bytes_pinned to approximate how much space
we have pinned. It's approximate because if we remove a reference to an
extent we may free it, but there may be more references to it than we
know of at that point, but we account it as pinned at the creation time,
and then it's properly accounted when the delayed ref runs.
The way we account for pinned space is if the
delayed_ref_head->total_ref_mod is < 0, because that is clearly a
freeing option. However there is another case, and that is where
->total_ref_mod == 0 && ->must_insert_reserved == 1.
When we allocate a new extent, we have ->total_ref_mod == 1 and we have
->must_insert_reserved == 1. This is used to indicate that it is a
brand new extent and will need to have its extent entry added before we
modify any references on the delayed ref head. But if we subsequently
remove that extent reference, our ->total_ref_mod will be 0, and that
space will be pinned and freed. Accounting for this case properly
allows for generic/371 to pass with my delayed refs patches applied.
It's important to note that this problem exists without the referenced
patches, it just was uncovered by them.
CC: stable@vger.kernel.org # 5.10
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we pass things around to figure out if we maybe freeing data
based on the state of the delayed refs head. This makes the accounting
sort of confusing and hard to follow, as it's distinctly separate from
the delayed ref heads stuff, but also depends on it entirely.
Fix this by explicitly adjusting the space_info->total_bytes_pinned in
the delayed refs code. We now have two places where we modify this
counter, once where we create the delayed and destroy the delayed refs,
and once when we pin and unpin the extents. This means there is a
slight overlap between delayed refs and the pin/unpin mechanisms, but
this is simply used by the ENOSPC infrastructure to determine if we need
to commit the transaction, so there's no adverse affect from this, we
might simply commit thinking it will give us enough space when it might
not.
CC: stable@vger.kernel.org # 5.10
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that the btrfs' codebase is clean of almost all W=1 warnings let's
enable those checks unconditionally for the entire fs/btrfs/ and its
subdirectories to catch potential errors during development.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add some comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes warning:
fs/btrfs/zoned.c:491:6: warning: variable ‘zone_size’ set but not used [-Wunused-but-set-variable]
491 | u64 zone_size;
which got introduced in 12659251ca ("btrfs: implement log-structured
superblock for ZONED mode"). We'll enable the warning by default and
want clean build until the relevant zoned patches land.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This makes the file W=1 clean and fixes the following warnings:
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search'
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search'
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search'
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search'
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search'
fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search'
fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit'
fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit'
fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit'
fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit'
fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit'
fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit'
fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit'
fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit'
fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit'
fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit'
fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages'
fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With these fixes space-info.c is clear for W=1 warnings, namely the
following ones are fixed:
fs/btrfs/space-info.c:575: warning: Function parameter or member 'fs_info' not described in 'may_commit_transaction'
fs/btrfs/space-info.c:575: warning: Function parameter or member 'space_info' not described in 'may_commit_transaction'
fs/btrfs/space-info.c:1231: warning: Function parameter or member 'fs_info' not described in 'handle_reserve_ticket'
fs/btrfs/space-info.c:1231: warning: Function parameter or member 'space_info' not described in 'handle_reserve_ticket'
fs/btrfs/space-info.c:1231: warning: Function parameter or member 'ticket' not described in 'handle_reserve_ticket'
fs/btrfs/space-info.c:1231: warning: Function parameter or member 'flush' not described in 'handle_reserve_ticket'
fs/btrfs/space-info.c:1315: warning: Function parameter or member 'fs_info' not described in '__reserve_bytes'
fs/btrfs/space-info.c:1315: warning: Function parameter or member 'space_info' not described in '__reserve_bytes'
fs/btrfs/space-info.c:1315: warning: Function parameter or member 'orig_bytes' not described in '__reserve_bytes'
fs/btrfs/space-info.c:1315: warning: Function parameter or member 'flush' not described in '__reserve_bytes'
fs/btrfs/space-info.c:1427: warning: Function parameter or member 'root' not described in 'btrfs_reserve_metadata_bytes'
fs/btrfs/space-info.c:1427: warning: Function parameter or member 'block_rsv' not described in 'btrfs_reserve_metadata_bytes'
fs/btrfs/space-info.c:1427: warning: Function parameter or member 'orig_bytes' not described in 'btrfs_reserve_metadata_bytes'
fs/btrfs/space-info.c:1427: warning: Function parameter or member 'flush' not described in 'btrfs_reserve_metadata_bytes'
fs/btrfs/space-info.c:1462: warning: Function parameter or member 'fs_info' not described in 'btrfs_reserve_data_bytes'
fs/btrfs/space-info.c:1462: warning: Function parameter or member 'bytes' not described in 'btrfs_reserve_data_bytes'
fs/btrfs/space-info.c:1462: warning: Function parameter or member 'flush' not described in 'btrfs_reserve_data_bytes'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes following warnings:
fs/btrfs/delalloc-space.c:205: warning: Function parameter or member 'inode' not described in 'btrfs_inode_rsv_release'
fs/btrfs/delalloc-space.c:205: warning: Function parameter or member 'qgroup_free' not described in 'btrfs_inode_rsv_release'
fs/btrfs/delalloc-space.c:472: warning: Function parameter or member 'reserved' not described in 'btrfs_delalloc_release_space'
fs/btrfs/delalloc-space.c:472: warning: Function parameter or member 'qgroup_free' not described in 'btrfs_delalloc_release_space'
fs/btrfs/delalloc-space.c:472: warning: Excess function parameter 'release_bytes' description in 'btrfs_delalloc_release_space'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes fs/btrfs/inode.c:3101: warning: Function parameter or member 'fs_info' not described in 'btrfs_wait_on_delayed_iputs'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes fs/btrfs/block-group.c:1570: warning: Function parameter or member 'fs_info' not described in 'btrfs_rmap_block'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes fs/btrfs/discard.c:203: warning: Function parameter or member 'now' not described in 'peek_discard_list'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes following W=1 warnings:
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'root' not described in '__btrfs_write_out_cache'
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'inode' not described in '__btrfs_write_out_cache'
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'ctl' not described in '__btrfs_write_out_cache'
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'block_group' not described in '__btrfs_write_out_cache'
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'io_ctl' not described in '__btrfs_write_out_cache'
fs/btrfs/free-space-cache.c:1317: warning: Function parameter or member 'trans' not described in '__btrfs_write_out_cache'
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes the following warnings:
fs/btrfs/delayed-ref.c:80: warning: Function parameter or member 'fs_info' not described in 'btrfs_delayed_refs_rsv_release'
fs/btrfs/delayed-ref.c:80: warning: Function parameter or member 'nr' not described in 'btrfs_delayed_refs_rsv_release'
fs/btrfs/delayed-ref.c:128: warning: Function parameter or member 'fs_info' not described in 'btrfs_migrate_to_delayed_refs_rsv'
fs/btrfs/delayed-ref.c:128: warning: Function parameter or member 'src' not described in 'btrfs_migrate_to_delayed_refs_rsv'
fs/btrfs/delayed-ref.c:128: warning: Function parameter or member 'num_bytes' not described in 'btrfs_migrate_to_delayed_refs_rsv'
fs/btrfs/delayed-ref.c:174: warning: Function parameter or member 'fs_info' not described in 'btrfs_delayed_refs_rsv_refill'
fs/btrfs/delayed-ref.c:174: warning: Function parameter or member 'flush' not described in 'btrfs_delayed_refs_rsv_refill'
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes following W=1 warnings:
fs/btrfs/file-item.c:27: warning: Cannot understand * @inode: the inode we want to update the disk_i_size for
on line 27 - I thought it was a doc line
fs/btrfs/file-item.c:65: warning: Cannot understand * @inode - the inode we're modifying
on line 65 - I thought it was a doc line
fs/btrfs/file-item.c:91: warning: Cannot understand * @inode - the inode we're modifying
on line 91 - I thought it was a doc line
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes the following compiler warnings:
fs/btrfs/extent_map.c:601: warning: Function parameter or member 'fs_info' not described in 'btrfs_add_extent_mapping'
fs/btrfs/extent_map.c:601: warning: Function parameter or member 'em_tree' not described in 'btrfs_add_extent_mapping'
fs/btrfs/extent_map.c:601: warning: Function parameter or member 'em_in' not described in 'btrfs_add_extent_mapping'
fs/btrfs/extent_map.c:601: warning: Function parameter or member 'start' not described in 'btrfs_add_extent_mapping'
fs/btrfs/extent_map.c:601: warning: Function parameter or member 'len' not described in 'btrfs_add_extent_mapping'
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes fs/btrfs/extent_map.c:399: warning: Function parameter or member
'modified' not described in 'add_extent_mapping'
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
