It really wants a btrfs_inode and will allow submit_compressed_extents
to be completely converted to btrfs_inode in follow up patches.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It really wants btrfs_inode and not a vfs inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't use the generic vfs inode for anything use btrfs_inode
directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't use the vfs inode for anything, can just as easily take
btrfs_inode. Follow up patches will convert callers as well.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is internal btrfs function what really needs the vfs_inode only for
igrab and a tracepoint.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The 'trans_list' member of an ordered extent was used to keep track of the
ordered extents for which a transaction commit had to wait. These were
ordered extents that were started and logged by an fsync. However we don't
do that anymore and before we stopped doing it we changed the approach to
wait for the ordered extents in commit 161c3549b4 ("Btrfs: change how
we wait for pending ordered extents"), which stopped using that list and
therefore the 'trans_list' member is not used anymore since that commit.
So just remove it since it's doing nothing and making each ordered extent
structure waste memory (2 pointers).
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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 'log_list' member of an ordered extent was used keep track of which
ordered extents we needed to wait after logging metadata, but is not used
anymore since commit 5636cf7d6d ("btrfs: remove the logged extents
infrastructure"), as we now always wait on ordered extent completion
before logging metadata. So just remove it since it's doing nothing and
making each ordered extent structure waste more memory (2 pointers).
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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 CPU and on-disk keys are mapped to two different structures because
of the endianness. There's an intermediate buffer used to do the
conversion, but this is not necessary when CPU and on-disk endianness
match.
Add optimized versions of helpers that take disk_key and use the buffer
directly for CPU keys or drop the intermediate buffer and conversion.
This saves a lot of stack space accross many functions and removes about
6K of generated binary code:
text data bss dec hex filename
1090439 17468 14912 1122819 112203 pre/btrfs.ko
1084613 17456 14912 1116981 110b35 post/btrfs.ko
Delta: -5826
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Before this patch, qgroup completely relies on per-inode extent io tree
to detect reserved data space leak.
However previous bug has already shown how release page before
btrfs_finish_ordered_io() could lead to leak, and since it's
QGROUP_RESERVED bit cleared without triggering qgroup rsv, it can't be
detected by per-inode extent io tree.
So this patch adds another (and hopefully the final) safety net to catch
qgroup data reserved space leak. At least the new safety net catches
all the leaks during development, so it should be pretty useful in the
real world.
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>
[BUG]
The following simple workload from fsstress can lead to qgroup reserved
data space leak:
0/0: creat f0 x:0 0 0
0/0: creat add id=0,parent=-1
0/1: write f0[259 1 0 0 0 0] [600030,27288] 0
0/4: dwrite - xfsctl(XFS_IOC_DIOINFO) f0[259 1 0 0 64 627318] return 25, fallback to stat()
0/4: dwrite f0[259 1 0 0 64 627318] [610304,106496] 0
This would cause btrfs qgroup to leak 20480 bytes for data reserved
space. If btrfs qgroup limit is enabled, such leak can lead to
unexpected early EDQUOT and unusable space.
[CAUSE]
When doing direct IO, kernel will try to writeback existing buffered
page cache, then invalidate them:
generic_file_direct_write()
|- filemap_write_and_wait_range();
|- invalidate_inode_pages2_range();
However for btrfs, the bi_end_io hook doesn't finish all its heavy work
right after bio ends. In fact, it delays its work further:
submit_extent_page(end_io_func=end_bio_extent_writepage);
end_bio_extent_writepage()
|- btrfs_writepage_endio_finish_ordered()
|- btrfs_init_work(finish_ordered_fn);
<<< Work queue execution >>>
finish_ordered_fn()
|- btrfs_finish_ordered_io();
|- Clear qgroup bits
This means, when filemap_write_and_wait_range() returns,
btrfs_finish_ordered_io() is not guaranteed to be executed, thus the
qgroup bits for related range are not cleared.
Now into how the leak happens, this will only focus on the overlapping
part of buffered and direct IO part.
1. After buffered write
The inode had the following range with QGROUP_RESERVED bit:
596 616K
|///////////////|
Qgroup reserved data space: 20K
2. Writeback part for range [596K, 616K)
Write back finished, but btrfs_finish_ordered_io() not get called
yet.
So we still have:
596K 616K
|///////////////|
Qgroup reserved data space: 20K
3. Pages for range [596K, 616K) get released
This will clear all qgroup bits, but don't update the reserved data
space.
So we have:
596K 616K
| |
Qgroup reserved data space: 20K
That number doesn't match the qgroup bit range anymore.
4. Dio prepare space for range [596K, 700K)
Qgroup reserved data space for that range, we got:
596K 616K 700K
|///////////////|///////////////////////|
Qgroup reserved data space: 20K + 104K = 124K
5. btrfs_finish_ordered_range() gets executed for range [596K, 616K)
Qgroup free reserved space for that range, we got:
596K 616K 700K
| |///////////////////////|
We need to free that range of reserved space.
Qgroup reserved data space: 124K - 20K = 104K
6. btrfs_finish_ordered_range() gets executed for range [596K, 700K)
However qgroup bit for range [596K, 616K) is already cleared in
previous step, so we only free 84K for qgroup reserved space.
596K 616K 700K
| | |
We need to free that range of reserved space.
Qgroup reserved data space: 104K - 84K = 20K
Now there is no way to release that 20K unless disabling qgroup or
unmounting the fs.
[FIX]
This patch will change the timing of btrfs_qgroup_release/free_data()
call. Here it uses buffered COW write as an example.
The new timing | The old timing
----------------------------------------+---------------------------------------
btrfs_buffered_write() | btrfs_buffered_write()
|- btrfs_qgroup_reserve_data() | |- btrfs_qgroup_reserve_data()
|
btrfs_run_delalloc_range() | btrfs_run_delalloc_range()
|- btrfs_add_ordered_extent() |
|- btrfs_qgroup_release_data() |
The reserved is passed into |
btrfs_ordered_extent structure |
|
btrfs_finish_ordered_io() | btrfs_finish_ordered_io()
|- The reserved space is passed to | |- btrfs_qgroup_release_data()
btrfs_qgroup_record | The resereved space is passed
| to btrfs_qgroup_recrod
|
btrfs_qgroup_account_extents() | btrfs_qgroup_account_extents()
|- btrfs_qgroup_free_refroot() | |- btrfs_qgroup_free_refroot()
The point of such change is to ensure, when ordered extents are
submitted, the qgroup reserved space is already released, to keep the
timing aligned with file_write_and_wait_range().
So that qgroup data reserved space is all bound to btrfs_ordered_extent
and solve the timing mismatch.
Fixes: f695fdcef8 ("btrfs: qgroup: Introduce functions to release/free qgroup reserve data space")
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The incoming qgroup reserved space timing will move the data reservation
to ordered extent completely.
However in btrfs_punch_hole_lock_range() will call
btrfs_invalidate_page(), which will clear QGROUP_RESERVED bit for the
range.
In current stage it's OK, but if we're making ordered extents handle the
reserved space, then btrfs_punch_hole_lock_range() can clear the
QGROUP_RESERVED bit before we submit ordered extent, leading to qgroup
reserved space leakage.
So here change the timing to make reserve data space after
btrfs_punch_hole_lock_range().
The new timing is fine for either current code or the new code.
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>
This is to prepare for the incoming timing change of qgroup reserved
data space and ordered extent.
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>
Function insert_reserved_file_extent() takes a long list of parameters,
which are all for btrfs_file_extent_item, even including two reserved
members, encryption and other_encoding.
This makes the parameter list unnecessary long for a function which only
gets called twice.
This patch will refactor the parameter list, by using
btrfs_file_extent_item as parameter directly to hugely reduce the number
of parameters.
Also, since there are only two callers, one in btrfs_finish_ordered_io()
which inserts file extent for ordered extent, and one
__btrfs_prealloc_file_range().
These two call sites have completely different context, where ordered
extent can be compressed, but will always be regular extent, while the
preallocated one is never going to be compressed and always has PREALLOC
type.
So use two small wrapper for these two different call sites to improve
readability.
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>
Add proper variable for the scrub page and use it instead of repeatedly
dereferencing the other structures.
Signed-off-by: David Sterba <dsterba@suse.com>
Use a simpler iteration over tree block pages, same what csum_tree_block
does: first page always exists, loop over the rest.
Signed-off-by: David Sterba <dsterba@suse.com>
Add proper variable for the scrub page and use it instead of repeatedly
dereferencing the other structures.
Signed-off-by: David Sterba <dsterba@suse.com>
Add proper variable for the scrub page and use it instead of repeatedly
dereferencing the other structures.
Signed-off-by: David Sterba <dsterba@suse.com>
The page contents with the checksum is available during the entire
function so we don't need to make a copy.
Signed-off-by: David Sterba <dsterba@suse.com>
BTRFS_SUPER_INFO_SIZE is 4096, and fits to a page on all supported
architectures, so we can calculate the checksum in one go.
Signed-off-by: David Sterba <dsterba@suse.com>
As the page mapping has been removed, rename the variables to 'kaddr'
that we use everywhere else. The type is changed to 'char *' so pointer
arithmetic works without casts.
Signed-off-by: David Sterba <dsterba@suse.com>
All pages that scrub uses in the scrub_block::pagev array are allocated
with GFP_KERNEL and never part of any mapping, so kmap is not necessary,
we only need to know the page address.
In scrub_write_page_to_dev_replace we don't even need to call
flush_dcache_page because of the same reason as above.
Signed-off-by: David Sterba <dsterba@suse.com>
This patch introduces a new "rescue=" mount option group for all mount
options for data recovery.
Different rescue sub options are seperated by ':'. E.g
"ro,rescue=nologreplay:usebackuproot".
The original plan was to use ';', but ';' needs to be escaped/quoted,
or it will be interpreted by bash, similar to '|'.
And obviously, user can specify rescue options one by one like:
"ro,rescue=nologreplay,rescue=usebackuproot".
The following mount options are converted to "rescue=", old mount
options are deprecated but still available for compatibility purpose:
- usebackuproot
Now it's "rescue=usebackuproot"
- nologreplay
Now it's "rescue=nologreplay"
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We currently use btrfs_check_data_free_space() when allocating space for
relocating data extents, but that is not necessary because that function
combines btrfs_alloc_data_chunk_ondemand(), which does the actual space
reservation, and btrfs_qgroup_reserve_data().
We can use btrfs_alloc_data_chunk_ondemand() directly because we know we
do not need to reserve qgroup space since we are dealing with a relocation
tree, which can never have qgroups (btrfs_qgroup_reserve_data() does
nothing as is_fstree() returns false for a relocation tree).
Conversely we can use btrfs_free_reserved_data_space_noquota() directly
instead of btrfs_free_reserved_data_space(), since we had no qgroup
reservation when allocating space.
This change is preparatory work for another patch in this series that
makes relocation reserve the exact amount of space it needs to relocate
a data block group. The function btrfs_check_data_free_space() has
the incovenient of requiring a start offset argument and we will want to
be able to allocate space for multiple ranges, which are not consecutive,
at once.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The start argument for btrfs_free_reserved_data_space_noquota() is only
used to make sure the amount of bytes we decrement from the bytes_may_use
counter of the data space_info object is aligned to the filesystem's
sector size. It serves no other purpose.
All its current callers always pass a length argument that is already
aligned to the sector size, so we can make the start argument go away.
In fact its presence makes it impossible to use it in a context where we
just want to free a number of bytes for a range for which either we do
not know its start offset or for freeing multiple ranges at once (which
are not contiguous).
This change is preparatory work for a patch (third patch in this series)
that makes relocation of data block groups that are not full reserve less
data space.
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>
As there is a dump_stack() done on memory allocation failures, these
messages might as well be deleted instead.
Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor tweaks ]
Signed-off-by: David Sterba <dsterba@suse.com>
Use the helper function where it is open coded to increment the
block_group reference count As btrfs_get_block_group() is a one-liner we
could have open-coded it, but its partner function
btrfs_put_block_group() isn't one-liner which does the free part in it.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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_return_cluster_to_free_space() returns only 0. And all its
parent functions don't need the return value either so make this a void
function.
Further, as none of the callers of btrfs_return_cluster_to_free_space()
is actually using the return from this function, make this function also
return void.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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>
Initially when the 'removed' flag was added to a block group to avoid
races between block group removal and fitrim, by commit 04216820fe
("Btrfs: fix race between fs trimming and block group remove/allocation"),
we had to lock the chunks mutex because we could be moving the block
group from its current list, the pending chunks list, into the pinned
chunks list, or we could just be adding it to the pinned chunks if it was
not in the pending chunks list. Both lists were protected by the chunk
mutex.
However we no longer have those lists since commit 1c11b63eff
("btrfs: replace pending/pinned chunks lists with io tree"), and locking
the chunk mutex is no longer necessary because of that. The same happens
at btrfs_unfreeze_block_group(), we lock the chunk mutex because the block
group's extent map could be part of the pinned chunks list and the call
to remove_extent_mapping() could be deleting it from that list, which
used to be protected by that mutex.
So just remove those lock and unlock calls as they are not needed anymore.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When find_first_block_group() finds a block group item in the extent-tree,
it does a lookup of the object in the extent mapping tree and does further
checks on the item.
Factor out this step from find_first_block_group() so we can further
simplify the code.
While we're at it, we can also just return early in
find_first_block_group(), if the tree slot isn't found.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We already have an fs_info in our function parameters, there's no need
to do the maths again and get fs_info from the extent_root just to get
the mapping_tree.
Instead directly grab the mapping_tree from fs_info.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Adresses held in 'logical' array are always guaranteed to fall within
the boundaries of the block group. That is, 'start' can never be
smaller than cache->start. This invariant follows from the way the
address are calculated in btrfs_rmap_block:
stripe_nr = physical - map->stripes[i].physical;
stripe_nr = div64_u64(stripe_nr, map->stripe_len);
bytenr = chunk_start + stripe_nr * io_stripe_size;
I.e it's always some IO stripe within the given chunk.
Exploit this invariant to simplify the body of the loop by removing the
unnecessary 'if' since its 'else' part is the one always executed.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
extent_map::orig_block_len contains the size of a physical stripe when
it's used to describe block groups (calculated in read_one_chunk via
calc_stripe_length or calculated in decide_stripe_size and then assigned
to extent_map::orig_block_len in create_chunk). Exploit this fact to get
the size directly rather than opencoding the calculations. No functional
changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The call to btrfs_btree_balance_dirty has been there since the early
days of BTRFS, when the btree was directly modified from the write path,
hence dirtied btree inode pages. With the implementation of b888db2bd7
("Btrfs: Add delayed allocation to the extent based page tree code")
13 years ago the btree is no longer modified from the write path, hence
there is no point in calling this function. Just remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into master
Pull btrfs fixes from David Sterba:
"A few resouce leak fixes from recent patches, all are stable material.
The problems have been observed during testing or have a reproducer"
* tag 'for-5.8-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix mount failure caused by race with umount
btrfs: fix page leaks after failure to lock page for delalloc
btrfs: qgroup: fix data leak caused by race between writeback and truncate
btrfs: fix double free on ulist after backref resolution failure
It is possible to cause a btrfs mount to fail by racing it with a slow
umount. The crux of the sequence is generic_shutdown_super not yet
calling sop->put_super before btrfs_mount_root calls btrfs_open_devices.
If that occurs, btrfs_open_devices will decide the opened counter is
non-zero, increment it, and skip resetting fs_devices->total_rw_bytes to
0. From here, mount will call sget which will result in grab_super
trying to take the super block umount semaphore. That semaphore will be
held by the slow umount, so mount will block. Before up-ing the
semaphore, umount will delete the super block, resulting in mount's sget
reliably allocating a new one, which causes the mount path to dutifully
fill it out, and increment total_rw_bytes a second time, which causes
the mount to fail, as we see double the expected bytes.
Here is the sequence laid out in greater detail:
CPU0 CPU1
down_write sb->s_umount
btrfs_kill_super
kill_anon_super(sb)
generic_shutdown_super(sb);
shrink_dcache_for_umount(sb);
sync_filesystem(sb);
evict_inodes(sb); // SLOW
btrfs_mount_root
btrfs_scan_one_device
fs_devices = device->fs_devices
fs_info->fs_devices = fs_devices
// fs_devices-opened makes this a no-op
btrfs_open_devices(fs_devices, mode, fs_type)
s = sget(fs_type, test, set, flags, fs_info);
find sb in s_instances
grab_super(sb);
down_write(&s->s_umount); // blocks
sop->put_super(sb)
// sb->fs_devices->opened == 2; no-op
spin_lock(&sb_lock);
hlist_del_init(&sb->s_instances);
spin_unlock(&sb_lock);
up_write(&sb->s_umount);
return 0;
retry lookup
don't find sb in s_instances (deleted by CPU0)
s = alloc_super
return s;
btrfs_fill_super(s, fs_devices, data)
open_ctree // fs_devices total_rw_bytes improperly set!
btrfs_read_chunk_tree
read_one_dev // increment total_rw_bytes again!!
super_total_bytes < fs_devices->total_rw_bytes // ERROR!!!
To fix this, we clear total_rw_bytes from within btrfs_read_chunk_tree
before the calls to read_one_dev, while holding the sb umount semaphore
and the uuid mutex.
To reproduce, it is sufficient to dirty a decent number of inodes, then
quickly umount and mount.
for i in $(seq 0 500)
do
dd if=/dev/zero of="/mnt/foo/$i" bs=1M count=1
done
umount /mnt/foo&
mount /mnt/foo
does the trick for me.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When locking pages for delalloc, we check if it's dirty and mapping still
matches. If it does not match, we need to return -EAGAIN and release all
pages. Only the current page was put though, iterate over all the
remaining pages too.
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running tests like generic/013 on test device with btrfs quota
enabled, it can normally lead to data leak, detected at unmount time:
BTRFS warning (device dm-3): qgroup 0/5 has unreleased space, type 0 rsv 4096
------------[ cut here ]------------
WARNING: CPU: 11 PID: 16386 at fs/btrfs/disk-io.c:4142 close_ctree+0x1dc/0x323 [btrfs]
RIP: 0010:close_ctree+0x1dc/0x323 [btrfs]
Call Trace:
btrfs_put_super+0x15/0x17 [btrfs]
generic_shutdown_super+0x72/0x110
kill_anon_super+0x18/0x30
btrfs_kill_super+0x17/0x30 [btrfs]
deactivate_locked_super+0x3b/0xa0
deactivate_super+0x40/0x50
cleanup_mnt+0x135/0x190
__cleanup_mnt+0x12/0x20
task_work_run+0x64/0xb0
__prepare_exit_to_usermode+0x1bc/0x1c0
__syscall_return_slowpath+0x47/0x230
do_syscall_64+0x64/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
---[ end trace caf08beafeca2392 ]---
BTRFS error (device dm-3): qgroup reserved space leaked
[CAUSE]
In the offending case, the offending operations are:
2/6: writev f2X[269 1 0 0 0 0] [1006997,67,288] 0
2/7: truncate f2X[269 1 0 0 48 1026293] 18388 0
The following sequence of events could happen after the writev():
CPU1 (writeback) | CPU2 (truncate)
-----------------------------------------------------------------
btrfs_writepages() |
|- extent_write_cache_pages() |
|- Got page for 1003520 |
| 1003520 is Dirty, no writeback |
| So (!clear_page_dirty_for_io()) |
| gets called for it |
|- Now page 1003520 is Clean. |
| | btrfs_setattr()
| | |- btrfs_setsize()
| | |- truncate_setsize()
| | New i_size is 18388
|- __extent_writepage() |
| |- page_offset() > i_size |
|- btrfs_invalidatepage() |
|- Page is clean, so no qgroup |
callback executed
This means, the qgroup reserved data space is not properly released in
btrfs_invalidatepage() as the page is Clean.
[FIX]
Instead of checking the dirty bit of a page, call
btrfs_qgroup_free_data() unconditionally in btrfs_invalidatepage().
As qgroup rsv are completely bound to the QGROUP_RESERVED bit of
io_tree, not bound to page status, thus we won't cause double freeing
anyway.
Fixes: 0b34c261e2 ("btrfs: qgroup: Prevent qgroup->reserved from going subzero")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Two refcounting fixes and one prepartory patch for upcoming splice
cleanup:
- fix double put of block group with nodatacow
- fix missing block group put when remounting with discard=async
- explicitly set splice callback (no functional change), to ease
integrating splice cleanup patches"
* tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: wire up iter_file_splice_write
btrfs: fix double put of block group with nocow
btrfs: discard: add missing put when grabbing block group from unused list
btrfs implements the iter_write op and thus can use the more efficient
iov_iter based splice implementation. For now falling back to the less
efficient default is pretty harmless, but I have a pending series that
removes the default, and thus would cause btrfs to not support splice
at all.
Reported-by: Andy Lavr <andy.lavr@gmail.com>
Tested-by: Andy Lavr <andy.lavr@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While debugging a patch that I wrote I was hitting use-after-free panics
when accessing block groups on unmount. This turned out to be because
in the nocow case if we bail out of doing the nocow for whatever reason
we need to call btrfs_dec_nocow_writers() if we called the inc. This
puts our block group, but a few error cases does
if (nocow) {
btrfs_dec_nocow_writers();
goto error;
}
unfortunately, error is
error:
if (nocow)
btrfs_dec_nocow_writers();
so we get a double put on our block group. Fix this by dropping the
error cases calling of btrfs_dec_nocow_writers(), as it's handled at the
error label now.
Fixes: 762bf09893 ("btrfs: improve error handling in run_delalloc_nocow")
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>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- regression fix of a leak in global block reserve accounting
- fix a (hard to hit) race of readahead vs releasepage that could lead
to crash
- convert all remaining uses of comment fall through annotations to the
pseudo keyword
- fix crash when mounting a fuzzed image with -o recovery
* tag 'for-5.8-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: reset tree root pointer after error in init_tree_roots
btrfs: fix reclaim_size counter leak after stealing from global reserve
btrfs: fix fatal extent_buffer readahead vs releasepage race
btrfs: convert comments to fallthrough annotations
[BUG]
The following small test script can trigger ASSERT() at unmount time:
mkfs.btrfs -f $dev
mount $dev $mnt
mount -o remount,discard=async $mnt
umount $mnt
The call trace:
assertion failed: atomic_read(&block_group->count) == 1, in fs/btrfs/block-group.c:3431
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.h:3204!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 4 PID: 10389 Comm: umount Tainted: G O 5.8.0-rc3-custom+ #68
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
btrfs_free_block_groups.cold+0x22/0x55 [btrfs]
close_ctree+0x2cb/0x323 [btrfs]
btrfs_put_super+0x15/0x17 [btrfs]
generic_shutdown_super+0x72/0x110
kill_anon_super+0x18/0x30
btrfs_kill_super+0x17/0x30 [btrfs]
deactivate_locked_super+0x3b/0xa0
deactivate_super+0x40/0x50
cleanup_mnt+0x135/0x190
__cleanup_mnt+0x12/0x20
task_work_run+0x64/0xb0
__prepare_exit_to_usermode+0x1bc/0x1c0
__syscall_return_slowpath+0x47/0x230
do_syscall_64+0x64/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The code:
ASSERT(atomic_read(&block_group->count) == 1);
btrfs_put_block_group(block_group);
[CAUSE]
Obviously it's some btrfs_get_block_group() call doesn't get its put
call.
The offending btrfs_get_block_group() happens here:
void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
{
if (list_empty(&bg->bg_list)) {
btrfs_get_block_group(bg);
list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
}
}
So every call sites removing the block group from unused_bgs list should
reduce the ref count of that block group.
However for async discard, it didn't follow the call convention:
void btrfs_discard_punt_unused_bgs_list(struct btrfs_fs_info *fs_info)
{
list_for_each_entry_safe(block_group, next, &fs_info->unused_bgs,
bg_list) {
list_del_init(&block_group->bg_list);
btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
}
}
And in btrfs_discard_queue_work(), it doesn't call
btrfs_put_block_group() either.
[FIX]
Fix the problem by reducing the reference count when we grab the block
group from unused_bgs list.
Reported-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Fixes: 6e80d4f8c4 ("btrfs: handle empty block_group removal for async discard")
CC: stable@vger.kernel.org # 5.6+
Tested-by: Marcos Paulo de Souza <mpdesouza@suse.com>
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>
Eric reported an issue where mounting -o recovery with a fuzzed fs
resulted in a kernel panic. This is because we tried to free the tree
node, except it was an error from the read. Fix this by properly
resetting the tree_root->node == NULL in this case. The panic was the
following
BTRFS warning (device loop0): failed to read tree root
BUG: kernel NULL pointer dereference, address: 000000000000001f
RIP: 0010:free_extent_buffer+0xe/0x90 [btrfs]
Call Trace:
free_root_extent_buffers.part.0+0x11/0x30 [btrfs]
free_root_pointers+0x1a/0xa2 [btrfs]
open_ctree+0x1776/0x18a5 [btrfs]
btrfs_mount_root.cold+0x13/0xfa [btrfs]
? selinux_fs_context_parse_param+0x37/0x80
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
fc_mount+0xe/0x30
vfs_kern_mount.part.0+0x71/0x90
btrfs_mount+0x147/0x3e0 [btrfs]
? cred_has_capability+0x7c/0x120
? legacy_get_tree+0x27/0x40
legacy_get_tree+0x27/0x40
vfs_get_tree+0x25/0xb0
do_mount+0x735/0xa40
__x64_sys_mount+0x8e/0xd0
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Nik says: this is problematic only if we fail on the last iteration of
the loop as this results in init_tree_roots returning err value with
tree_root->node = -ERR. Subsequently the caller does: fail_tree_roots
which calls free_root_pointers on the bogus value.
Reported-by: Eric Sandeen <sandeen@redhat.com>
Fixes: b8522a1e5f ("btrfs: Factor out tree roots initialization during mount")
CC: stable@vger.kernel.org # 5.5+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add details how the pointer gets dereferenced ]
Signed-off-by: David Sterba <dsterba@suse.com>
Under somewhat convoluted conditions, it is possible to attempt to
release an extent_buffer that is under io, which triggers a BUG_ON in
btrfs_release_extent_buffer_pages.
This relies on a few different factors. First, extent_buffer reads done
as readahead for searching use WAIT_NONE, so they free the local extent
buffer reference while the io is outstanding. However, they should still
be protected by TREE_REF. However, if the system is doing signficant
reclaim, and simultaneously heavily accessing the extent_buffers, it is
possible for releasepage to race with two concurrent readahead attempts
in a way that leaves TREE_REF unset when the readahead extent buffer is
released.
Essentially, if two tasks race to allocate a new extent_buffer, but the
winner who attempts the first io is rebuffed by a page being locked
(likely by the reclaim itself) then the loser will still go ahead with
issuing the readahead. The loser's call to find_extent_buffer must also
race with the reclaim task reading the extent_buffer's refcount as 1 in
a way that allows the reclaim to re-clear the TREE_REF checked by
find_extent_buffer.
The following represents an example execution demonstrating the race:
CPU0 CPU1 CPU2
reada_for_search reada_for_search
readahead_tree_block readahead_tree_block
find_create_tree_block find_create_tree_block
alloc_extent_buffer alloc_extent_buffer
find_extent_buffer // not found
allocates eb
lock pages
associate pages to eb
insert eb into radix tree
set TREE_REF, refs == 2
unlock pages
read_extent_buffer_pages // WAIT_NONE
not uptodate (brand new eb)
lock_page
if !trylock_page
goto unlock_exit // not an error
free_extent_buffer
release_extent_buffer
atomic_dec_and_test refs to 1
find_extent_buffer // found
try_release_extent_buffer
take refs_lock
reads refs == 1; no io
atomic_inc_not_zero refs to 2
mark_buffer_accessed
check_buffer_tree_ref
// not STALE, won't take refs_lock
refs == 2; TREE_REF set // no action
read_extent_buffer_pages // WAIT_NONE
clear TREE_REF
release_extent_buffer
atomic_dec_and_test refs to 1
unlock_page
still not uptodate (CPU1 read failed on trylock_page)
locks pages
set io_pages > 0
submit io
return
free_extent_buffer
release_extent_buffer
dec refs to 0
delete from radix tree
btrfs_release_extent_buffer_pages
BUG_ON(io_pages > 0)!!!
We observe this at a very low rate in production and were also able to
reproduce it in a test environment by introducing some spurious delays
and by introducing probabilistic trylock_page failures.
To fix it, we apply check_tree_ref at a point where it could not
possibly be unset by a competing task: after io_pages has been
incremented. All the codepaths that clear TREE_REF check for io, so they
would not be able to clear it after this point until the io is done.
Stack trace, for reference:
[1417839.424739] ------------[ cut here ]------------
[1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841!
[1417839.447024] invalid opcode: 0000 [#1] SMP
[1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0
[1417839.517008] Code: ed e9 ...
[1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202
[1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028
[1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0
[1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238
[1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000
[1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90
[1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000
[1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0
[1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[1417839.731320] Call Trace:
[1417839.737103] release_extent_buffer+0x39/0x90
[1417839.746913] read_block_for_search.isra.38+0x2a3/0x370
[1417839.758645] btrfs_search_slot+0x260/0x9b0
[1417839.768054] btrfs_lookup_file_extent+0x4a/0x70
[1417839.778427] btrfs_get_extent+0x15f/0x830
[1417839.787665] ? submit_extent_page+0xc4/0x1c0
[1417839.797474] ? __do_readpage+0x299/0x7a0
[1417839.806515] __do_readpage+0x33b/0x7a0
[1417839.815171] ? btrfs_releasepage+0x70/0x70
[1417839.824597] extent_readpages+0x28f/0x400
[1417839.833836] read_pages+0x6a/0x1c0
[1417839.841729] ? startup_64+0x2/0x30
[1417839.849624] __do_page_cache_readahead+0x13c/0x1a0
[1417839.860590] filemap_fault+0x6c7/0x990
[1417839.869252] ? xas_load+0x8/0x80
[1417839.876756] ? xas_find+0x150/0x190
[1417839.884839] ? filemap_map_pages+0x295/0x3b0
[1417839.894652] __do_fault+0x32/0x110
[1417839.902540] __handle_mm_fault+0xacd/0x1000
[1417839.912156] handle_mm_fault+0xaa/0x1c0
[1417839.921004] __do_page_fault+0x242/0x4b0
[1417839.930044] ? page_fault+0x8/0x30
[1417839.937933] page_fault+0x1e/0x30
[1417839.945631] RIP: 0033:0x33c4bae
[1417839.952927] Code: Bad RIP value.
[1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206
[1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000
[1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
[1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8
[1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79
[1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Convert fall through comments to the pseudo-keyword which is now the
preferred way.
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-5.8-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A number of fixes, located in two areas, one performance fix and one
fixup for better integration with another patchset.
- bug fixes in nowait aio:
- fix snapshot creation hang after nowait-aio was used
- fix failure to write to prealloc extent past EOF
- don't block when extent range is locked
- block group fixes:
- relocation failure when scrub runs in parallel
- refcount fix when removing fails
- fix race between removal and creation
- space accounting fixes
- reinstante fast path check for log tree at unlink time, fixes
performance drop up to 30% in REAIM
- kzfree/kfree fixup to ease treewide patchset renaming kzfree"
* tag 'for-5.8-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: use kfree() in btrfs_ioctl_get_subvol_info()
btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IO
btrfs: fix RWF_NOWAIT write not failling when we need to cow
btrfs: fix failure of RWF_NOWAIT write into prealloc extent beyond eof
btrfs: fix hang on snapshot creation after RWF_NOWAIT write
btrfs: check if a log root exists before locking the log_mutex on unlink
btrfs: fix bytes_may_use underflow when running balance and scrub in parallel
btrfs: fix data block group relocation failure due to concurrent scrub
btrfs: fix race between block group removal and block group creation
btrfs: fix a block group ref counter leak after failure to remove block group
In btrfs_ioctl_get_subvol_info(), there is a classic case where kzalloc()
was incorrectly paired with kzfree(). According to David Sterba, there
isn't any sensitive information in the subvol_info that needs to be
cleared before freeing. So kzfree() isn't really needed, use kfree()
instead.
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be
held for a long time or for ongoing IO to complete.
However when calling check_can_nocow(), if the inode has prealloc extents
or has the NOCOW flag set, we can block on extent (file range) locks
through the call to btrfs_lock_and_flush_ordered_range(). Such lock can
take a significant amount of time to be available. For example, a fiemap
task may be running, and iterating through the entire file range checking
all extents and doing backref walking to determine if they are shared,
or a readpage operation may be in progress.
Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(),
after locking the file range we wait for any existing ordered extent that
is in progress to complete. Another operation that can take a significant
amount of time and defeat the purpose of RWF_NOWAIT.
So fix this by trying to lock the file range and if it's currently locked
return -EAGAIN to user space. If we are able to lock the file range without
waiting and there is an ordered extent in the range, return -EAGAIN as
well, instead of waiting for it to complete. Finally, don't bother trying
to lock the snapshot lock of the root when attempting a RWF_NOWAIT write,
as that is only important for buffered writes.
Fixes: edf064e7c6 ("btrfs: nowait aio support")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we attempt to do a RWF_NOWAIT write against a file range for which we
can only do NOCOW for a part of it, due to the existence of holes or
shared extents for example, we proceed with the write as if it were
possible to NOCOW the whole range.
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ touch /mnt/sdj/bar
$ chattr +C /mnt/sdj/bar
$ xfs_io -d -c "pwrite -S 0xab -b 256K 0 256K" /mnt/bar
wrote 262144/262144 bytes at offset 0
256 KiB, 1 ops; 0.0003 sec (694.444 MiB/sec and 2777.7778 ops/sec)
$ xfs_io -c "fpunch 64K 64K" /mnt/bar
$ sync
$ xfs_io -d -c "pwrite -N -V 1 -b 128K -S 0xfe 0 128K" /mnt/bar
wrote 131072/131072 bytes at offset 0
128 KiB, 1 ops; 0.0007 sec (160.051 MiB/sec and 1280.4097 ops/sec)
This last write should fail with -EAGAIN since the file range from 64K to
128K is a hole. On xfs it fails, as expected, but on ext4 it currently
succeeds because apparently it is expensive to check if there are extents
allocated for the whole range, but I'll check with the ext4 people.
Fix the issue by checking if check_can_nocow() returns a number of
NOCOW'able bytes smaller then the requested number of bytes, and if it
does return -EAGAIN.
Fixes: edf064e7c6 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we attempt to write to prealloc extent located after eof using a
RWF_NOWAIT write, we always fail with -EAGAIN.
We do actually check if we have an allocated extent for the write at
the start of btrfs_file_write_iter() through a call to check_can_nocow(),
but later when we go into the actual direct IO write path we simply
return -EAGAIN if the write starts at or beyond EOF.
Trivial to reproduce:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ touch /mnt/foo
$ chattr +C /mnt/foo
$ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foo
wrote 65536/65536 bytes at offset 0
64 KiB, 16 ops; 0.0004 sec (135.575 MiB/sec and 34707.1584 ops/sec)
$ xfs_io -c "falloc -k 64K 1M" /mnt/foo
$ xfs_io -d -c "pwrite -N -V 1 -S 0xfe -b 64K 64K 64K" /mnt/foo
pwrite: Resource temporarily unavailable
On xfs and ext4 the write succeeds, as expected.
Fix this by removing the wrong check at btrfs_direct_IO().
Fixes: edf064e7c6 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we do a successful RWF_NOWAIT write we end up locking the snapshot lock
of the inode, through a call to check_can_nocow(), but we never unlock it.
This means the next attempt to create a snapshot on the subvolume will
hang forever.
Trivial reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ touch /mnt/foobar
$ chattr +C /mnt/foobar
$ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foobar
$ xfs_io -d -c "pwrite -N -V 1 -S 0xfe 0 64K" /mnt/foobar
$ btrfs subvolume snapshot -r /mnt /mnt/snap
--> hangs
Fix this by unlocking the snapshot lock if check_can_nocow() returned
success.
Fixes: edf064e7c6 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This brings back an optimization that commit e678934cbe ("btrfs:
Remove unnecessary check from join_running_log_trans") removed, but in
a different form. So it's almost equivalent to a revert.
That commit removed an optimization where we avoid locking a root's
log_mutex when there is no log tree created in the current transaction.
The affected code path is triggered through unlink operations.
That commit was based on the assumption that the optimization was not
necessary because we used to have the following checks when the patch
was authored:
int btrfs_del_dir_entries_in_log(...)
{
(...)
if (dir->logged_trans < trans->transid)
return 0;
ret = join_running_log_trans(root);
(...)
}
int btrfs_del_inode_ref_in_log(...)
{
(...)
if (inode->logged_trans < trans->transid)
return 0;
ret = join_running_log_trans(root);
(...)
}
However before that patch was merged, another patch was merged first which
replaced those checks because they were buggy.
That other patch corresponds to commit 803f0f64d1 ("Btrfs: fix fsync
not persisting dentry deletions due to inode evictions"). The assumption
that if the logged_trans field of an inode had a smaller value then the
current transaction's generation (transid) meant that the inode was not
logged in the current transaction was only correct if the inode was not
evicted and reloaded in the current transaction. So the corresponding bug
fix changed those checks and replaced them with the following helper
function:
static bool inode_logged(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode)
{
if (inode->logged_trans == trans->transid)
return true;
if (inode->last_trans == trans->transid &&
test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) &&
!test_bit(BTRFS_FS_LOG_RECOVERING, &trans->fs_info->flags))
return true;
return false;
}
So if we have a subvolume without a log tree in the current transaction
(because we had no fsyncs), every time we unlink an inode we can end up
trying to lock the log_mutex of the root through join_running_log_trans()
twice, once for the inode being unlinked (by btrfs_del_inode_ref_in_log())
and once for the parent directory (with btrfs_del_dir_entries_in_log()).
This means if we have several unlink operations happening in parallel for
inodes in the same subvolume, and the those inodes and/or their parent
inode were changed in the current transaction, we end up having a lot of
contention on the log_mutex.
The test robots from intel reported a -30.7% performance regression for
a REAIM test after commit e678934cbe ("btrfs: Remove unnecessary check
from join_running_log_trans").
So just bring back the optimization to join_running_log_trans() where we
check first if a log root exists before trying to lock the log_mutex. This
is done by checking for a bit that is set on the root when a log tree is
created and removed when a log tree is freed (at transaction commit time).
Commit e678934cbe ("btrfs: Remove unnecessary check from
join_running_log_trans") was merged in the 5.4 merge window while commit
803f0f64d1 ("Btrfs: fix fsync not persisting dentry deletions due to
inode evictions") was merged in the 5.3 merge window. But the first
commit was actually authored before the second commit (May 23 2019 vs
June 19 2019).
Reported-by: kernel test robot <rong.a.chen@intel.com>
Link: https://lore.kernel.org/lkml/20200611090233.GL12456@shao2-debian/
Fixes: e678934cbe ("btrfs: Remove unnecessary check from join_running_log_trans")
CC: stable@vger.kernel.org # 5.4+
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>
When balance and scrub are running in parallel it is possible to end up
with an underflow of the bytes_may_use counter of the data space_info
object, which triggers a warning like the following:
[134243.793196] BTRFS info (device sdc): relocating block group 1104150528 flags data
[134243.806891] ------------[ cut here ]------------
[134243.807561] WARNING: CPU: 1 PID: 26884 at fs/btrfs/space-info.h:125 btrfs_add_reserved_bytes+0x1da/0x280 [btrfs]
[134243.808819] Modules linked in: btrfs blake2b_generic xor (...)
[134243.815779] CPU: 1 PID: 26884 Comm: kworker/u8:8 Tainted: G W 5.6.0-rc7-btrfs-next-58 #5
[134243.816944] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[134243.818389] Workqueue: writeback wb_workfn (flush-btrfs-108483)
[134243.819186] RIP: 0010:btrfs_add_reserved_bytes+0x1da/0x280 [btrfs]
[134243.819963] Code: 0b f2 85 (...)
[134243.822271] RSP: 0018:ffffa4160aae7510 EFLAGS: 00010287
[134243.822929] RAX: 000000000000c000 RBX: ffff96159a8c1000 RCX: 0000000000000000
[134243.823816] RDX: 0000000000008000 RSI: 0000000000000000 RDI: ffff96158067a810
[134243.824742] RBP: ffff96158067a800 R08: 0000000000000001 R09: 0000000000000000
[134243.825636] R10: ffff961501432a40 R11: 0000000000000000 R12: 000000000000c000
[134243.826532] R13: 0000000000000001 R14: ffffffffffff4000 R15: ffff96158067a810
[134243.827432] FS: 0000000000000000(0000) GS:ffff9615baa00000(0000) knlGS:0000000000000000
[134243.828451] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[134243.829184] CR2: 000055bd7e414000 CR3: 00000001077be004 CR4: 00000000003606e0
[134243.830083] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[134243.830975] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[134243.831867] Call Trace:
[134243.832211] find_free_extent+0x4a0/0x16c0 [btrfs]
[134243.832846] btrfs_reserve_extent+0x91/0x180 [btrfs]
[134243.833487] cow_file_range+0x12d/0x490 [btrfs]
[134243.834080] fallback_to_cow+0x82/0x1b0 [btrfs]
[134243.834689] ? release_extent_buffer+0x121/0x170 [btrfs]
[134243.835370] run_delalloc_nocow+0x33f/0xa30 [btrfs]
[134243.836032] btrfs_run_delalloc_range+0x1ea/0x6d0 [btrfs]
[134243.836725] ? find_lock_delalloc_range+0x221/0x250 [btrfs]
[134243.837450] writepage_delalloc+0xe8/0x150 [btrfs]
[134243.838059] __extent_writepage+0xe8/0x4c0 [btrfs]
[134243.838674] extent_write_cache_pages+0x237/0x530 [btrfs]
[134243.839364] extent_writepages+0x44/0xa0 [btrfs]
[134243.839946] do_writepages+0x23/0x80
[134243.840401] __writeback_single_inode+0x59/0x700
[134243.841006] writeback_sb_inodes+0x267/0x5f0
[134243.841548] __writeback_inodes_wb+0x87/0xe0
[134243.842091] wb_writeback+0x382/0x590
[134243.842574] ? wb_workfn+0x4a2/0x6c0
[134243.843030] wb_workfn+0x4a2/0x6c0
[134243.843468] process_one_work+0x26d/0x6a0
[134243.843978] worker_thread+0x4f/0x3e0
[134243.844452] ? process_one_work+0x6a0/0x6a0
[134243.844981] kthread+0x103/0x140
[134243.845400] ? kthread_create_worker_on_cpu+0x70/0x70
[134243.846030] ret_from_fork+0x3a/0x50
[134243.846494] irq event stamp: 0
[134243.846892] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[134243.847682] hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134243.848687] softirqs last enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134243.849913] softirqs last disabled at (0): [<0000000000000000>] 0x0
[134243.850698] ---[ end trace bd7c03622e0b0a96 ]---
[134243.851335] ------------[ cut here ]------------
When relocating a data block group, for each extent allocated in the
block group we preallocate another extent with the same size for the
data relocation inode (we do it at prealloc_file_extent_cluster()).
We reserve space by calling btrfs_check_data_free_space(), which ends
up incrementing the data space_info's bytes_may_use counter, and
then call btrfs_prealloc_file_range() to allocate the extent, which
always decrements the bytes_may_use counter by the same amount.
The expectation is that writeback of the data relocation inode always
follows a NOCOW path, by writing into the preallocated extents. However,
when starting writeback we might end up falling back into the COW path,
because the block group that contains the preallocated extent was turned
into RO mode by a scrub running in parallel. The COW path then calls the
extent allocator which ends up calling btrfs_add_reserved_bytes(), and
this function decrements the bytes_may_use counter of the data space_info
object by an amount corresponding to the size of the allocated extent,
despite we haven't previously incremented it. When the counter currently
has a value smaller then the allocated extent we reset the counter to 0
and emit a warning, otherwise we just decrement it and slowly mess up
with this counter which is crucial for space reservation, the end result
can be granting reserved space to tasks when there isn't really enough
free space, and having the tasks fail later in critical places where
error handling consists of a transaction abort or hitting a BUG_ON().
Fix this by making sure that if we fallback to the COW path for a data
relocation inode, we increment the bytes_may_use counter of the data
space_info object. The COW path will then decrement it at
btrfs_add_reserved_bytes() on success or through its error handling part
by a call to extent_clear_unlock_delalloc() (which ends up calling
btrfs_clear_delalloc_extent() that does the decrement operation) in case
of an error.
Test case btrfs/061 from fstests could sporadically trigger this.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When running relocation of a data block group while scrub is running in
parallel, it is possible that the relocation will fail and abort the
current transaction with an -EINVAL error:
[134243.988595] BTRFS info (device sdc): found 14 extents, stage: move data extents
[134243.999871] ------------[ cut here ]------------
[134244.000741] BTRFS: Transaction aborted (error -22)
[134244.001692] WARNING: CPU: 0 PID: 26954 at fs/btrfs/ctree.c:1071 __btrfs_cow_block+0x6a7/0x790 [btrfs]
[134244.003380] Modules linked in: btrfs blake2b_generic xor raid6_pq (...)
[134244.012577] CPU: 0 PID: 26954 Comm: btrfs Tainted: G W 5.6.0-rc7-btrfs-next-58 #5
[134244.014162] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[134244.016184] RIP: 0010:__btrfs_cow_block+0x6a7/0x790 [btrfs]
[134244.017151] Code: 48 c7 c7 (...)
[134244.020549] RSP: 0018:ffffa41607863888 EFLAGS: 00010286
[134244.021515] RAX: 0000000000000000 RBX: ffff9614bdfe09c8 RCX: 0000000000000000
[134244.022822] RDX: 0000000000000001 RSI: ffffffffb3d63980 RDI: 0000000000000001
[134244.024124] RBP: ffff961589e8c000 R08: 0000000000000000 R09: 0000000000000001
[134244.025424] R10: ffffffffc0ae5955 R11: 0000000000000000 R12: ffff9614bd530d08
[134244.026725] R13: ffff9614ced41b88 R14: ffff9614bdfe2a48 R15: 0000000000000000
[134244.028024] FS: 00007f29b63c08c0(0000) GS:ffff9615ba600000(0000) knlGS:0000000000000000
[134244.029491] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[134244.030560] CR2: 00007f4eb339b000 CR3: 0000000130d6e006 CR4: 00000000003606f0
[134244.031997] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[134244.033153] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[134244.034484] Call Trace:
[134244.034984] btrfs_cow_block+0x12b/0x2b0 [btrfs]
[134244.035859] do_relocation+0x30b/0x790 [btrfs]
[134244.036681] ? do_raw_spin_unlock+0x49/0xc0
[134244.037460] ? _raw_spin_unlock+0x29/0x40
[134244.038235] relocate_tree_blocks+0x37b/0x730 [btrfs]
[134244.039245] relocate_block_group+0x388/0x770 [btrfs]
[134244.040228] btrfs_relocate_block_group+0x161/0x2e0 [btrfs]
[134244.041323] btrfs_relocate_chunk+0x36/0x110 [btrfs]
[134244.041345] btrfs_balance+0xc06/0x1860 [btrfs]
[134244.043382] ? btrfs_ioctl_balance+0x27c/0x310 [btrfs]
[134244.045586] btrfs_ioctl_balance+0x1ed/0x310 [btrfs]
[134244.045611] btrfs_ioctl+0x1880/0x3760 [btrfs]
[134244.049043] ? do_raw_spin_unlock+0x49/0xc0
[134244.049838] ? _raw_spin_unlock+0x29/0x40
[134244.050587] ? __handle_mm_fault+0x11b3/0x14b0
[134244.051417] ? ksys_ioctl+0x92/0xb0
[134244.052070] ksys_ioctl+0x92/0xb0
[134244.052701] ? trace_hardirqs_off_thunk+0x1a/0x1c
[134244.053511] __x64_sys_ioctl+0x16/0x20
[134244.054206] do_syscall_64+0x5c/0x280
[134244.054891] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[134244.055819] RIP: 0033:0x7f29b51c9dd7
[134244.056491] Code: 00 00 00 (...)
[134244.059767] RSP: 002b:00007ffcccc1dd08 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[134244.061168] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f29b51c9dd7
[134244.062474] RDX: 00007ffcccc1dda0 RSI: 00000000c4009420 RDI: 0000000000000003
[134244.063771] RBP: 0000000000000003 R08: 00005565cea4b000 R09: 0000000000000000
[134244.065032] R10: 0000000000000541 R11: 0000000000000202 R12: 00007ffcccc2060a
[134244.066327] R13: 00007ffcccc1dda0 R14: 0000000000000002 R15: 00007ffcccc1dec0
[134244.067626] irq event stamp: 0
[134244.068202] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[134244.069351] hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134244.070909] softirqs last enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134244.072392] softirqs last disabled at (0): [<0000000000000000>] 0x0
[134244.073432] ---[ end trace bd7c03622e0b0a99 ]---
The -EINVAL error comes from the following chain of function calls:
__btrfs_cow_block() <-- aborts the transaction
btrfs_reloc_cow_block()
replace_file_extents()
get_new_location() <-- returns -EINVAL
When relocating a data block group, for each allocated extent of the block
group, we preallocate another extent (at prealloc_file_extent_cluster()),
associated with the data relocation inode, and then dirty all its pages.
These preallocated extents have, and must have, the same size that extents
from the data block group being relocated have.
Later before we start the relocation stage that updates pointers (bytenr
field of file extent items) to point to the the new extents, we trigger
writeback for the data relocation inode. The expectation is that writeback
will write the pages to the previously preallocated extents, that it
follows the NOCOW path. That is generally the case, however, if a scrub
is running it may have turned the block group that contains those extents
into RO mode, in which case writeback falls back to the COW path.
However in the COW path instead of allocating exactly one extent with the
expected size, the allocator may end up allocating several smaller extents
due to free space fragmentation - because we tell it at cow_file_range()
that the minimum allocation size can match the filesystem's sector size.
This later breaks the relocation's expectation that an extent associated
to a file extent item in the data relocation inode has the same size as
the respective extent pointed by a file extent item in another tree - in
this case the extent to which the relocation inode poins to is smaller,
causing relocation.c:get_new_location() to return -EINVAL.
For example, if we are relocating a data block group X that has a logical
address of X and the block group has an extent allocated at the logical
address X + 128KiB with a size of 64KiB:
1) At prealloc_file_extent_cluster() we allocate an extent for the data
relocation inode with a size of 64KiB and associate it to the file
offset 128KiB (X + 128KiB - X) of the data relocation inode. This
preallocated extent was allocated at block group Z;
2) A scrub running in parallel turns block group Z into RO mode and
starts scrubing its extents;
3) Relocation triggers writeback for the data relocation inode;
4) When running delalloc (btrfs_run_delalloc_range()), we try first the
NOCOW path because the data relocation inode has BTRFS_INODE_PREALLOC
set in its flags. However, because block group Z is in RO mode, the
NOCOW path (run_delalloc_nocow()) falls back into the COW path, by
calling cow_file_range();
5) At cow_file_range(), in the first iteration of the while loop we call
btrfs_reserve_extent() to allocate a 64KiB extent and pass it a minimum
allocation size of 4KiB (fs_info->sectorsize). Due to free space
fragmentation, btrfs_reserve_extent() ends up allocating two extents
of 32KiB each, each one on a different iteration of that while loop;
6) Writeback of the data relocation inode completes;
7) Relocation proceeds and ends up at relocation.c:replace_file_extents(),
with a leaf which has a file extent item that points to the data extent
from block group X, that has a logical address (bytenr) of X + 128KiB
and a size of 64KiB. Then it calls get_new_location(), which does a
lookup in the data relocation tree for a file extent item starting at
offset 128KiB (X + 128KiB - X) and belonging to the data relocation
inode. It finds a corresponding file extent item, however that item
points to an extent that has a size of 32KiB, which doesn't match the
expected size of 64KiB, resuling in -EINVAL being returned from this
function and propagated up to __btrfs_cow_block(), which aborts the
current transaction.
To fix this make sure that at cow_file_range() when we call the allocator
we pass it a minimum allocation size corresponding the desired extent size
if the inode belongs to the data relocation tree, otherwise pass it the
filesystem's sector size as the minimum allocation size.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a race between block group removal and block group creation
when the removal is completed by a task running fitrim or scrub. When
this happens we end up failing the block group creation with an error
-EEXIST since we attempt to insert a duplicate block group item key
in the extent tree. That results in a transaction abort.
The race happens like this:
1) Task A is doing a fitrim, and at btrfs_trim_block_group() it freezes
block group X with btrfs_freeze_block_group() (until very recently
that was named btrfs_get_block_group_trimming());
2) Task B starts removing block group X, either because it's now unused
or due to relocation for example. So at btrfs_remove_block_group(),
while holding the chunk mutex and the block group's lock, it sets
the 'removed' flag of the block group and it sets the local variable
'remove_em' to false, because the block group is currently frozen
(its 'frozen' counter is > 0, until very recently this counter was
named 'trimming');
3) Task B unlocks the block group and the chunk mutex;
4) Task A is done trimming the block group and unfreezes the block group
by calling btrfs_unfreeze_block_group() (until very recently this was
named btrfs_put_block_group_trimming()). In this function we lock the
block group and set the local variable 'cleanup' to true because we
were able to decrement the block group's 'frozen' counter down to 0 and
the flag 'removed' is set in the block group.
Since 'cleanup' is set to true, it locks the chunk mutex and removes
the extent mapping representing the block group from the mapping tree;
5) Task C allocates a new block group Y and it picks up the logical address
that block group X had as the logical address for Y, because X was the
block group with the highest logical address and now the second block
group with the highest logical address, the last in the fs mapping tree,
ends at an offset corresponding to block group X's logical address (this
logical address selection is done at volumes.c:find_next_chunk()).
At this point the new block group Y does not have yet its item added
to the extent tree (nor the corresponding device extent items and
chunk item in the device and chunk trees). The new group Y is added to
the list of pending block groups in the transaction handle;
6) Before task B proceeds to removing the block group item for block
group X from the extent tree, which has a key matching:
(X logical offset, BTRFS_BLOCK_GROUP_ITEM_KEY, length)
task C while ending its transaction handle calls
btrfs_create_pending_block_groups(), which finds block group Y and
tries to insert the block group item for Y into the exten tree, which
fails with -EEXIST since logical offset is the same that X had and
task B hasn't yet deleted the key from the extent tree.
This failure results in a transaction abort, producing a stack like
the following:
------------[ cut here ]------------
BTRFS: Transaction aborted (error -17)
WARNING: CPU: 2 PID: 19736 at fs/btrfs/block-group.c:2074 btrfs_create_pending_block_groups+0x1eb/0x260 [btrfs]
Modules linked in: btrfs blake2b_generic xor raid6_pq (...)
CPU: 2 PID: 19736 Comm: fsstress Tainted: G W 5.6.0-rc7-btrfs-next-58 #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_create_pending_block_groups+0x1eb/0x260 [btrfs]
Code: ff ff ff 48 8b 55 50 f0 48 (...)
RSP: 0018:ffffa4160a1c7d58 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff961581909d98 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffffb3d63990 RDI: 0000000000000001
RBP: ffff9614f3356a58 R08: 0000000000000000 R09: 0000000000000001
R10: ffff9615b65b0040 R11: 0000000000000000 R12: ffff961581909c10
R13: ffff9615b0c32000 R14: ffff9614f3356ab0 R15: ffff9614be779000
FS: 00007f2ce2841e80(0000) GS:ffff9615bae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555f18780000 CR3: 0000000131d34005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btrfs_start_dirty_block_groups+0x398/0x4e0 [btrfs]
btrfs_commit_transaction+0xd0/0xc50 [btrfs]
? btrfs_attach_transaction_barrier+0x1e/0x50 [btrfs]
? __ia32_sys_fdatasync+0x20/0x20
iterate_supers+0xdb/0x180
ksys_sync+0x60/0xb0
__ia32_sys_sync+0xa/0x10
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2ce1d4d5b7
Code: 83 c4 08 48 3d 01 (...)
RSP: 002b:00007ffd8b558c58 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 000000000000002c RCX: 00007f2ce1d4d5b7
RDX: 00000000ffffffff RSI: 00000000186ba07b RDI: 000000000000002c
RBP: 0000555f17b9e520 R08: 0000000000000012 R09: 000000000000ce00
R10: 0000000000000078 R11: 0000000000000202 R12: 0000000000000032
R13: 0000000051eb851f R14: 00007ffd8b558cd0 R15: 0000555f1798ec20
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
softirqs last enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace bd7c03622e0b0a9c ]---
Fix this simply by making btrfs_remove_block_group() remove the block
group's item from the extent tree before it flags the block group as
removed. Also make the free space deletion from the free space tree
before flagging the block group as removed, to avoid a similar race
with adding and removing free space entries for the free space tree.
Fixes: 04216820fe ("Btrfs: fix race between fs trimming and block group remove/allocation")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When removing a block group, if we fail to delete the block group's item
from the extent tree, we jump to the 'out' label and end up decrementing
the block group's reference count once only (by 1), resulting in a counter
leak because the block group at that point was already removed from the
block group cache rbtree - so we have to decrement the reference count
twice, once for the rbtree and once for our lookup at the start of the
function.
There is a second bug where if removing the free space tree entries (the
call to remove_block_group_free_space()) fails we end up jumping to the
'out_put_group' label but end up decrementing the reference count only
once, when we should have done it twice, since we have already removed
the block group from the block group cache rbtree. This happens because
the reference count decrement for the rbtree reference happens after
attempting to remove the free space tree entries, which is far away from
the place where we remove the block group from the rbtree.
To make things less error prone, decrement the reference count for the
rbtree immediately after removing the block group from it. This also
eleminates the need for two different exit labels on error, renaming
'out_put_label' to just 'out' and removing the old 'out'.
Fixes: f6033c5e33 ("btrfs: fix block group leak when removing fails")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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>
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Merge tag 'for-5.8-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This reverts the direct io port to iomap infrastructure of btrfs
merged in the first pull request. We found problems in invalidate page
that don't seem to be fixable as regressions or without changing iomap
code that would not affect other filesystems.
There are four reverts in total, but three of them are followup
cleanups needed to revert a43a67a2d7 cleanly. The result is the
buffer head based implementation of direct io.
Reverts are not great, but under current circumstances I don't see
better options"
* tag 'for-5.8-part2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Revert "btrfs: switch to iomap_dio_rw() for dio"
Revert "fs: remove dio_end_io()"
Revert "btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK"
Revert "btrfs: split btrfs_direct_IO to read and write part"
This reverts commit a43a67a2d7.
This patch reverts the main part of switching direct io implementation
to iomap infrastructure. There's a problem in invalidate page that
couldn't be solved as regression in this development cycle.
The problem occurs when buffered and direct io are mixed, and the ranges
overlap. Although this is not recommended, filesystems implement
measures or fallbacks to make it somehow work. In this case, fallback to
buffered IO would be an option for btrfs (this already happens when
direct io is done on compressed data), but the change would be needed in
the iomap code, bringing new semantics to other filesystems.
Another problem arises when again the buffered and direct ios are mixed,
invalidation fails, then -EIO is set on the mapping and fsync will fail,
though there's no real error.
There have been discussions how to fix that, but revert seems to be the
least intrusive option.
Link: https://lore.kernel.org/linux-btrfs/20200528192103.xm45qoxqmkw7i5yl@fiona/
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit 5f008163a5.
The patch is a simplification after direct IO port to iomap
infrastructure, which gets reverted.
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit d8f3e73587.
The patch is a cleanup of direct IO port to iomap infrastructure,
which gets reverted.
Signed-off-by: David Sterba <dsterba@suse.com>
* Fix performance problems found in dioread_nolock now that it is the
default, caused by transaction leaks.
* Clean up fiemap handling in ext4
* Clean up and refactor multiple block allocator (mballoc) code
* Fix a problem with mballoc with a smaller file systems running out
of blocks because they couldn't properly use blocks that had been
reserved by inode preallocation.
* Fixed a race in ext4_sync_parent() versus rename()
* Simplify the error handling in the extent manipulation code
* Make sure all metadata I/O errors are felected to ext4_ext_dirty()'s and
ext4_make_inode_dirty()'s callers.
* Avoid passing an error pointer to brelse in ext4_xattr_set()
* Fix race which could result to freeing an inode on the dirty last
in data=journal mode.
* Fix refcount handling if ext4_iget() fails
* Fix a crash in generic/019 caused by a corrupted extent node
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"A lot of bug fixes and cleanups for ext4, including:
- Fix performance problems found in dioread_nolock now that it is the
default, caused by transaction leaks.
- Clean up fiemap handling in ext4
- Clean up and refactor multiple block allocator (mballoc) code
- Fix a problem with mballoc with a smaller file systems running out
of blocks because they couldn't properly use blocks that had been
reserved by inode preallocation.
- Fixed a race in ext4_sync_parent() versus rename()
- Simplify the error handling in the extent manipulation code
- Make sure all metadata I/O errors are felected to
ext4_ext_dirty()'s and ext4_make_inode_dirty()'s callers.
- Avoid passing an error pointer to brelse in ext4_xattr_set()
- Fix race which could result to freeing an inode on the dirty last
in data=journal mode.
- Fix refcount handling if ext4_iget() fails
- Fix a crash in generic/019 caused by a corrupted extent node"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (58 commits)
ext4: avoid unnecessary transaction starts during writeback
ext4: don't block for O_DIRECT if IOCB_NOWAIT is set
ext4: remove the access_ok() check in ext4_ioctl_get_es_cache
fs: remove the access_ok() check in ioctl_fiemap
fs: handle FIEMAP_FLAG_SYNC in fiemap_prep
fs: move fiemap range validation into the file systems instances
iomap: fix the iomap_fiemap prototype
fs: move the fiemap definitions out of fs.h
fs: mark __generic_block_fiemap static
ext4: remove the call to fiemap_check_flags in ext4_fiemap
ext4: split _ext4_fiemap
ext4: fix fiemap size checks for bitmap files
ext4: fix EXT4_MAX_LOGICAL_BLOCK macro
add comment for ext4_dir_entry_2 file_type member
jbd2: avoid leaking transaction credits when unreserving handle
ext4: drop ext4_journal_free_reserved()
ext4: mballoc: use lock for checking free blocks while retrying
ext4: mballoc: refactor ext4_mb_good_group()
ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling
ext4: mballoc: refactor ext4_mb_discard_preallocations()
...
By moving FIEMAP_FLAG_SYNC handling to fiemap_prep we ensure it is
handled once instead of duplicated, but can still be done under fs locks,
like xfs/iomap intended with its duplicate handling. Also make sure the
error value of filemap_write_and_wait is propagated to user space.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-8-hch@lst.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Replace fiemap_check_flags with a fiemap_prep helper that also takes the
inode and mapped range, and performs the sanity check and truncation
previously done in fiemap_check_range. This way the validation is inside
the file system itself and thus properly works for the stacked overlayfs
case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-7-hch@lst.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
No need to pull the fiemap definitions into almost every file in the
kernel build.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-5-hch@lst.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Merge tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"Highlights:
- speedup dead root detection during orphan cleanup, eg. when there
are many deleted subvolumes waiting to be cleaned, the trees are
now looked up in radix tree instead of a O(N^2) search
- snapshot creation with inherited qgroup will mark the qgroup
inconsistent, requires a rescan
- send will emit file capabilities after chown, this produces a
stream that does not need postprocessing to set the capabilities
again
- direct io ported to iomap infrastructure, cleaned up and simplified
code, notably removing last use of struct buffer_head in btrfs code
Core changes:
- factor out backreference iteration, to be used by ordinary
backreferences and relocation code
- improved global block reserve utilization
* better logic to serialize requests
* increased maximum available for unlink
* improved handling on large pages (64K)
- direct io cleanups and fixes
* simplify layering, where cloned bios were unnecessarily created
for some cases
* error handling fixes (submit, endio)
* remove repair worker thread, used to avoid deadlocks during
repair
- refactored block group reading code, preparatory work for new type
of block group storage that should improve mount time on large
filesystems
Cleanups:
- cleaned up (and slightly sped up) set/get helpers for metadata data
structure members
- root bit REF_COWS got renamed to SHAREABLE to reflect the that the
blocks of the tree get shared either among subvolumes or with the
relocation trees
Fixes:
- when subvolume deletion fails due to ENOSPC, the filesystem is not
turned read-only
- device scan deals with devices from other filesystems that changed
ownership due to overwrite (mkfs)
- fix a race between scrub and block group removal/allocation
- fix long standing bug of a runaway balance operation, printing the
same line to the syslog, caused by a stale status bit on a reloc
tree that prevented progress
- fix corrupt log due to concurrent fsync of inodes with shared
extents
- fix space underflow for NODATACOW and buffered writes when it for
some reason needs to fallback to COW mode"
* tag 'for-5.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (133 commits)
btrfs: fix space_info bytes_may_use underflow during space cache writeout
btrfs: fix space_info bytes_may_use underflow after nocow buffered write
btrfs: fix wrong file range cleanup after an error filling dealloc range
btrfs: remove redundant local variable in read_block_for_search
btrfs: open code key_search
btrfs: split btrfs_direct_IO to read and write part
btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK
fs: remove dio_end_io()
btrfs: switch to iomap_dio_rw() for dio
iomap: remove lockdep_assert_held()
iomap: add a filesystem hook for direct I/O bio submission
fs: export generic_file_buffered_read()
btrfs: turn space cache writeout failure messages into debug messages
btrfs: include error on messages about failure to write space/inode caches
btrfs: remove useless 'fail_unlock' label from btrfs_csum_file_blocks()
btrfs: do not ignore error from btrfs_next_leaf() when inserting checksums
btrfs: make checksum item extension more efficient
btrfs: fix corrupt log due to concurrent fsync of inodes with shared extents
btrfs: unexport btrfs_compress_set_level()
btrfs: simplify iget helpers
...
Merge updates from Andrew Morton:
"A few little subsystems and a start of a lot of MM patches.
Subsystems affected by this patch series: squashfs, ocfs2, parisc,
vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup,
swap, memcg, pagemap, memory-failure, vmalloc, kasan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits)
kasan: move kasan_report() into report.c
mm/mm_init.c: report kasan-tag information stored in page->flags
ubsan: entirely disable alignment checks under UBSAN_TRAP
kasan: fix clang compilation warning due to stack protector
x86/mm: remove vmalloc faulting
mm: remove vmalloc_sync_(un)mappings()
x86/mm/32: implement arch_sync_kernel_mappings()
x86/mm/64: implement arch_sync_kernel_mappings()
mm/ioremap: track which page-table levels were modified
mm/vmalloc: track which page-table levels were modified
mm: add functions to track page directory modifications
s390: use __vmalloc_node in stack_alloc
powerpc: use __vmalloc_node in alloc_vm_stack
arm64: use __vmalloc_node in arch_alloc_vmap_stack
mm: remove vmalloc_user_node_flags
mm: switch the test_vmalloc module to use __vmalloc_node
mm: remove __vmalloc_node_flags_caller
mm: remove both instances of __vmalloc_node_flags
mm: remove the prot argument to __vmalloc_node
mm: remove the pgprot argument to __vmalloc
...
Since the new pair function is introduced, we can call them to clean the
code in btrfs.
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Link: http://lkml.kernel.org/r/20200517214718.468-4-guoqing.jiang@cloud.ionos.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement the new readahead method in btrfs using the new
readahead_page_batch() function.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-18-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull uaccess/access_ok updates from Al Viro:
"Removals of trivially pointless access_ok() calls.
Note: the fiemap stuff was removed from the series, since they are
duplicates with part of ext4 series carried in Ted's tree"
* 'uaccess.access_ok' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vmci_host: get rid of pointless access_ok()
hfi1: get rid of pointless access_ok()
usb: get rid of pointless access_ok() calls
lpfc_debugfs: get rid of pointless access_ok()
efi_test: get rid of pointless access_ok()
drm_read(): get rid of pointless access_ok()
via-pmu: don't bother with access_ok()
drivers/crypto/ccp/sev-dev.c: get rid of pointless access_ok()
omapfb: get rid of pointless access_ok() calls
amifb: get rid of pointless access_ok() calls
drivers/fpga/dfl-afu-dma-region.c: get rid of pointless access_ok()
drivers/fpga/dfl-fme-pr.c: get rid of pointless access_ok()
cm4000_cs.c cmm_ioctl(): get rid of pointless access_ok()
nvram: drop useless access_ok()
n_hdlc_tty_read(): remove pointless access_ok()
tomoyo_write_control(): get rid of pointless access_ok()
btrfs_ioctl_send(): don't bother with access_ok()
fat_dir_ioctl(): hadn't needed that access_ok() for more than a decade...
dlmfs_file_write(): get rid of pointless access_ok()
We always preallocate a data extent for writing a free space cache, which
causes writeback to always try the nocow path first, since the free space
inode has the prealloc bit set in its flags.
However if the block group that contains the data extent for the space
cache has been turned to RO mode due to a running scrub or balance for
example, we have to fallback to the cow path. In that case once a new data
extent is allocated we end up calling btrfs_add_reserved_bytes(), which
decrements the counter named bytes_may_use from the data space_info object
with the expection that this counter was previously incremented with the
same amount (the size of the data extent).
However when we started writeout of the space cache at cache_save_setup(),
we incremented the value of the bytes_may_use counter through a call to
btrfs_check_data_free_space() and then decremented it through a call to
btrfs_prealloc_file_range_trans() immediately after. So when starting the
writeback if we fallback to cow mode we have to increment the counter
bytes_may_use of the data space_info again to compensate for the extent
allocation done by the cow path.
When this issue happens we are incorrectly decrementing the bytes_may_use
counter and when its current value is smaller then the amount we try to
subtract we end up with the following warning:
------------[ cut here ]------------
WARNING: CPU: 3 PID: 657 at fs/btrfs/space-info.h:115 btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
Modules linked in: btrfs blake2b_generic xor raid6_pq libcrc32c (...)
CPU: 3 PID: 657 Comm: kworker/u8:7 Tainted: G W 5.6.0-rc7-btrfs-next-58 #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
Workqueue: writeback wb_workfn (flush-btrfs-1591)
RIP: 0010:btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
Code: ff ff 48 (...)
RSP: 0000:ffffa41608f13660 EFLAGS: 00010287
RAX: 0000000000001000 RBX: ffff9615b93ae400 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffff9615b96ab410
RBP: fffffffffffee000 R08: 0000000000000001 R09: 0000000000000000
R10: ffff961585e62a40 R11: 0000000000000000 R12: ffff9615b96ab400
R13: ffff9615a1a2a000 R14: 0000000000012000 R15: ffff9615b93ae400
FS: 0000000000000000(0000) GS:ffff9615bb200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cbbc2ae178 CR3: 0000000115794006 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
find_free_extent+0x4a0/0x16c0 [btrfs]
btrfs_reserve_extent+0x91/0x180 [btrfs]
cow_file_range+0x12d/0x490 [btrfs]
btrfs_run_delalloc_range+0x9f/0x6d0 [btrfs]
? find_lock_delalloc_range+0x221/0x250 [btrfs]
writepage_delalloc+0xe8/0x150 [btrfs]
__extent_writepage+0xe8/0x4c0 [btrfs]
extent_write_cache_pages+0x237/0x530 [btrfs]
extent_writepages+0x44/0xa0 [btrfs]
do_writepages+0x23/0x80
__writeback_single_inode+0x59/0x700
writeback_sb_inodes+0x267/0x5f0
__writeback_inodes_wb+0x87/0xe0
wb_writeback+0x382/0x590
? wb_workfn+0x4a2/0x6c0
wb_workfn+0x4a2/0x6c0
process_one_work+0x26d/0x6a0
worker_thread+0x4f/0x3e0
? process_one_work+0x6a0/0x6a0
kthread+0x103/0x140
? kthread_create_worker_on_cpu+0x70/0x70
ret_from_fork+0x3a/0x50
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
softirqs last enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace bd7c03622e0b0a52 ]---
------------[ cut here ]------------
So fix this by incrementing the bytes_may_use counter of the data
space_info when we fallback to the cow path. If the cow path is successful
the counter is decremented after extent allocation (by
btrfs_add_reserved_bytes()), if it fails it ends up being decremented as
well when clearing the delalloc range (extent_clear_unlock_delalloc()).
This could be triggered sporadically by the test case btrfs/061 from
fstests.
Fixes: 82d5902d9c ("Btrfs: Support reading/writing on disk free ino cache")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When doing a buffered write we always try to reserve data space for it,
even when the file has the NOCOW bit set or the write falls into a file
range covered by a prealloc extent. This is done both because it is
expensive to check if we can do a nocow write (checking if an extent is
shared through reflinks or if there's a hole in the range for example),
and because when writeback starts we might actually need to fallback to
COW mode (for example the block group containing the target extents was
turned into RO mode due to a scrub or balance).
When we are unable to reserve data space we check if we can do a nocow
write, and if we can, we proceed with dirtying the pages and setting up
the range for delalloc. In this case the bytes_may_use counter of the
data space_info object is not incremented, unlike in the case where we
are able to reserve data space (done through btrfs_check_data_free_space()
which calls btrfs_alloc_data_chunk_ondemand()).
Later when running delalloc we attempt to start writeback in nocow mode
but we might revert back to cow mode, for example because in the meanwhile
a block group was turned into RO mode by a scrub or relocation. The cow
path after successfully allocating an extent ends up calling
btrfs_add_reserved_bytes(), which expects the bytes_may_use counter of
the data space_info object to have been incremented before - but we did
not do it when the buffered write started, since there was not enough
available data space. So btrfs_add_reserved_bytes() ends up decrementing
the bytes_may_use counter anyway, and when the counter's current value
is smaller then the size of the allocated extent we get a stack trace
like the following:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 20138 at fs/btrfs/space-info.h:115 btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
Modules linked in: btrfs blake2b_generic xor raid6_pq libcrc32c (...)
CPU: 0 PID: 20138 Comm: kworker/u8:15 Not tainted 5.6.0-rc7-btrfs-next-58 #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
Workqueue: writeback wb_workfn (flush-btrfs-1754)
RIP: 0010:btrfs_add_reserved_bytes+0x3d6/0x4e0 [btrfs]
Code: ff ff 48 (...)
RSP: 0018:ffffbda18a4b3568 EFLAGS: 00010287
RAX: 0000000000000000 RBX: ffff9ca076f5d800 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffff9ca068470410
RBP: fffffffffffff000 R08: 0000000000000001 R09: 0000000000000000
R10: ffff9ca079d58040 R11: 0000000000000000 R12: ffff9ca068470400
R13: ffff9ca0408b2000 R14: 0000000000001000 R15: ffff9ca076f5d800
FS: 0000000000000000(0000) GS:ffff9ca07a600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005605dbfe7048 CR3: 0000000138570006 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
find_free_extent+0x4a0/0x16c0 [btrfs]
btrfs_reserve_extent+0x91/0x180 [btrfs]
cow_file_range+0x12d/0x490 [btrfs]
run_delalloc_nocow+0x341/0xa40 [btrfs]
btrfs_run_delalloc_range+0x1ea/0x6d0 [btrfs]
? find_lock_delalloc_range+0x221/0x250 [btrfs]
writepage_delalloc+0xe8/0x150 [btrfs]
__extent_writepage+0xe8/0x4c0 [btrfs]
extent_write_cache_pages+0x237/0x530 [btrfs]
? btrfs_wq_submit_bio+0x9f/0xc0 [btrfs]
extent_writepages+0x44/0xa0 [btrfs]
do_writepages+0x23/0x80
__writeback_single_inode+0x59/0x700
writeback_sb_inodes+0x267/0x5f0
__writeback_inodes_wb+0x87/0xe0
wb_writeback+0x382/0x590
? wb_workfn+0x4a2/0x6c0
wb_workfn+0x4a2/0x6c0
process_one_work+0x26d/0x6a0
worker_thread+0x4f/0x3e0
? process_one_work+0x6a0/0x6a0
kthread+0x103/0x140
? kthread_create_worker_on_cpu+0x70/0x70
ret_from_fork+0x3a/0x50
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffff94ebdedf>] copy_process+0x74f/0x2020
softirqs last enabled at (0): [<ffffffff94ebdedf>] copy_process+0x74f/0x2020
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace f9f6ef8ec4cd8ec9 ]---
So to fix this, when falling back into cow mode check if space was not
reserved, by testing for the bit EXTENT_NORESERVE in the respective file
range, and if not, increment the bytes_may_use counter for the data
space_info object. Also clear the EXTENT_NORESERVE bit from the range, so
that if the cow path fails it decrements the bytes_may_use counter when
clearing the delalloc range (through the btrfs_clear_delalloc_extent()
callback).
Fixes: 7ee9e4405f ("Btrfs: check if we can nocow if we don't have data space")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If an error happens while running dellaloc in COW mode for a range, we can
end up calling extent_clear_unlock_delalloc() for a range that goes beyond
our range's end offset by 1 byte, which affects 1 extra page. This results
in clearing bits and doing page operations (such as a page unlock) outside
our target range.
Fix that by calling extent_clear_unlock_delalloc() with an inclusive end
offset, instead of an exclusive end offset, at cow_file_range().
Fixes: a315e68f6e ("Btrfs: fix invalid attempt to free reserved space on failure to cow range")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The local 'b' variable is only used to directly read values from passed
extent buffer. So eliminate it and directly use the input parameter.
Furthermore this shrinks the size of the following functions:
./scripts/bloat-o-meter ctree.orig fs/btrfs/ctree.o
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-73 (-73)
Function old new delta
read_block_for_search.isra 876 871 -5
push_node_left 1112 1044 -68
Total: Before=50348, After=50275, chg -0.14%
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 function wraps the optimisation implemented by d7396f0735
("Btrfs: optimize key searches in btrfs_search_slot") however this
optimisation is really used in only one place - btrfs_search_slot.
Just open code the optimisation and also add a comment explaining how it
works since it's not clear just by looking at the code - the key point
here is it depends on an internal invariant that BTRFS' btree provides,
namely intermediate pointers always contain the key at slot0 at the
child node. So in the case of exact match we can safely assume that the
given key will always be in slot 0 on lower levels.
Furthermore this results in a reduction of btrfs_search_slot's size:
./scripts/bloat-o-meter ctree.orig fs/btrfs/ctree.o
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-75 (-75)
Function old new delta
btrfs_search_slot 2783 2708 -75
Total: Before=50423, After=50348, chg -0.15%
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>
The read and write versions don't have anything in common except for the
call to iomap_dio_rw. So split this function, and merge each half into
its only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we now perform direct reads using i_rwsem, we can remove this
inode flag used to co-ordinate unlocked reads.
The truncate call takes i_rwsem. This means it is correctly synchronized
with concurrent direct reads.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Switch from __blockdev_direct_IO() to iomap_dio_rw().
Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
as iomap_begin() for iomap direct I/O functions. This function
allocates and locks all the blocks required for the I/O.
btrfs_submit_direct() is used as the submit_io() hook for direct I/O
ops.
Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.
We don't need address_space.direct_IO() anymore so set it to noop.
Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.
BTRFS direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.
Use iomap->iomap_end() to check for failed or incomplete direct I/O:
- for writes, call __endio_write_update_ordered()
- for reads, unlock extents
btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.
This patch removes last use of struct buffer_head from btrfs.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 1afb648e94 ("btrfs: use standard debug config option to
enable free-space-cache debug prints"), we started to log error messages
that were never logged before since there was no DEBUG macro defined
anywhere. This started to make test case btrfs/187 to fail very often,
as it greps for any btrfs error messages in dmesg/syslog and fails if
any is found:
(...)
btrfs/186 1s ... 2s
btrfs/187 - output mismatch (see .../results//btrfs/187.out.bad)
\--- tests/btrfs/187.out 2019-05-17 12:48:32.537340749 +0100
\+++ /home/fdmanana/git/hub/xfstests/results//btrfs/187.out.bad ...
\@@ -1,3 +1,8 @@
QA output created by 187
Create a readonly snapshot of 'SCRATCH_MNT' in 'SCRATCH_MNT/snap1'
Create a readonly snapshot of 'SCRATCH_MNT' in 'SCRATCH_MNT/snap2'
+[268364.139958] BTRFS error (device sdc): failed to write free space cache for block group 30408704
+[268380.156503] BTRFS error (device sdc): failed to write free space cache for block group 30408704
+[268380.161703] BTRFS error (device sdc): failed to write free space cache for block group 30408704
+[268380.253180] BTRFS error (device sdc): failed to write free space cache for block group 30408704
...
(Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/187.out ...
btrfs/188 4s ... 2s
(...)
The space cache write failures happen due to ENOSPC when attempting to
update the free space cache items in the root tree. This happens because
when starting or joining a transaction we don't know how many block
groups we will end up changing (due to extent allocation or release) and
therefore never reserve space for updating free space cache items.
More often than not, the free space cache writeout succeeds since the
metadata space info is not yet full nor very close to being full, but
when it is, the space cache writeout fails with ENOSPC.
Occasional failures to write space caches are not considered critical
since they can be rebuilt when mounting the filesystem or the next
attempt to write a free space cache in the next transaction commit might
succeed, so we used to hide those error messages with a preprocessor
check for the existence of the DEBUG macro that was never enabled
anywhere.
A few other generic test cases also trigger the error messages due to
ENOSPC failure when writing free space caches as well, however they don't
fail since they don't grep dmesg/syslog for any btrfs specific error
messages.
So change the messages from 'error' level to 'debug' level, as it doesn't
make much sense to have error messages triggered only if the debug macro
is enabled plus, more importantly, the error is not serious nor highly
unexpected.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the error messages logged when we fail to write a free space
cache or an inode cache are not very useful as they don't mention what
was the error. So include the error number in the messages.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The label 'fail_unlock' is pointless, all it does is to jump to the label
'out', so just remove it.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are currently treating any non-zero return value from btrfs_next_leaf()
the same way, by going to the code that inserts a new checksum item in the
tree. However if btrfs_next_leaf() returns an error (a value < 0), we
should just stop and return the error, and not behave as if nothing has
happened, since in that case we do not have a way to know if there is a
next leaf or we are currently at the last leaf already.
So fix that by returning the error from btrfs_next_leaf().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we want to add checksums into the checksums tree, or a log tree, we
try whenever possible to extend existing checksum items, as this helps
reduce amount of metadata space used, since adding a new item uses extra
metadata space for a btrfs_item structure (25 bytes).
However we have two inefficiencies in the current approach:
1) After finding a checksum item that covers a range with an end offset
that matches the start offset of the checksum range we want to insert,
we release the search path populated by btrfs_lookup_csum() and then
do another COW search on tree with the goal of getting additional
space for at least one checksum. Doing this path release and then
searching again is a waste of time because very often the leaf already
has enough free space for at least one more checksum;
2) After the COW search that guarantees we get free space in the leaf for
at least one more checksum, we end up not doing the extension of the
previous checksum item, and fallback to insertion of a new checksum
item, if the leaf doesn't have an amount of free space larger then the
space required for 2 checksums plus one btrfs_item structure - this is
pointless for two reasons:
a) We want to extend an existing item, so we don't need to account for
a btrfs_item structure (25 bytes);
b) We made the COW search with an insertion size for 1 single checksum,
so if the leaf ends up with a free space amount smaller then 2
checksums plus the size of a btrfs_item structure, we give up on the
extension of the existing item and jump to the 'insert' label, where
we end up releasing the path and then doing yet another search to
insert a new checksum item for a single checksum.
Fix these inefficiencies by doing the following:
- For case 1), before releasing the path just check if the leaf already
has enough space for at least 1 more checksum, and if it does, jump
directly to the item extension code, with releasing our current path,
which was already COWed by btrfs_lookup_csum();
- For case 2), fix the logic so that for item extension we require only
that the leaf has enough free space for 1 checksum, and not a minimum
of 2 checksums plus space for a btrfs_item structure.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we have extents shared amongst different inodes in the same subvolume,
if we fsync them in parallel we can end up with checksum items in the log
tree that represent ranges which overlap.
For example, consider we have inodes A and B, both sharing an extent that
covers the logical range from X to X + 64KiB:
1) Task A starts an fsync on inode A;
2) Task B starts an fsync on inode B;
3) Task A calls btrfs_csum_file_blocks(), and the first search in the
log tree, through btrfs_lookup_csum(), returns -EFBIG because it
finds an existing checksum item that covers the range from X - 64KiB
to X;
4) Task A checks that the checksum item has not reached the maximum
possible size (MAX_CSUM_ITEMS) and then releases the search path
before it does another path search for insertion (through a direct
call to btrfs_search_slot());
5) As soon as task A releases the path and before it does the search
for insertion, task B calls btrfs_csum_file_blocks() and gets -EFBIG
too, because there is an existing checksum item that has an end
offset that matches the start offset (X) of the checksum range we want
to log;
6) Task B releases the path;
7) Task A does the path search for insertion (through btrfs_search_slot())
and then verifies that the checksum item that ends at offset X still
exists and extends its size to insert the checksums for the range from
X to X + 64KiB;
8) Task A releases the path and returns from btrfs_csum_file_blocks(),
having inserted the checksums into an existing checksum item that got
its size extended. At this point we have one checksum item in the log
tree that covers the logical range from X - 64KiB to X + 64KiB;
9) Task B now does a search for insertion using btrfs_search_slot() too,
but it finds that the previous checksum item no longer ends at the
offset X, it now ends at an of offset X + 64KiB, so it leaves that item
untouched.
Then it releases the path and calls btrfs_insert_empty_item()
that inserts a checksum item with a key offset corresponding to X and
a size for inserting a single checksum (4 bytes in case of crc32c).
Subsequent iterations end up extending this new checksum item so that
it contains the checksums for the range from X to X + 64KiB.
So after task B returns from btrfs_csum_file_blocks() we end up with
two checksum items in the log tree that have overlapping ranges, one
for the range from X - 64KiB to X + 64KiB, and another for the range
from X to X + 64KiB.
Having checksum items that represent ranges which overlap, regardless of
being in the log tree or in the chekcsums tree, can lead to problems where
checksums for a file range end up not being found. This type of problem
has happened a few times in the past and the following commits fixed them
and explain in detail why having checksum items with overlapping ranges is
problematic:
27b9a8122f "Btrfs: fix csum tree corruption, duplicate and outdated checksums"
b84b8390d6 "Btrfs: fix file read corruption after extent cloning and fsync"
40e046acbd "Btrfs: fix missing data checksums after replaying a log tree"
Since this specific instance of the problem can only happen when logging
inodes, because it is the only case where concurrent attempts to insert
checksums for the same range can happen, fix the issue by using an extent
io tree as a range lock to serialize checksum insertion during inode
logging.
This issue could often be reproduced by the test case generic/457 from
fstests. When it happens it produces the following trace:
BTRFS critical (device dm-0): corrupt leaf: root=18446744073709551610 block=30625792 slot=42, csum end range (15020032) goes beyond the start range (15015936) of the next csum item
BTRFS info (device dm-0): leaf 30625792 gen 7 total ptrs 49 free space 2402 owner 18446744073709551610
BTRFS info (device dm-0): refs 1 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 15884
item 0 key (18446744073709551606 128 13979648) itemoff 3991 itemsize 4
item 1 key (18446744073709551606 128 13983744) itemoff 3987 itemsize 4
item 2 key (18446744073709551606 128 13987840) itemoff 3983 itemsize 4
item 3 key (18446744073709551606 128 13991936) itemoff 3979 itemsize 4
item 4 key (18446744073709551606 128 13996032) itemoff 3975 itemsize 4
item 5 key (18446744073709551606 128 14000128) itemoff 3971 itemsize 4
(...)
BTRFS error (device dm-0): block=30625792 write time tree block corruption detected
------------[ cut here ]------------
WARNING: CPU: 1 PID: 15884 at fs/btrfs/disk-io.c:539 btree_csum_one_bio+0x268/0x2d0 [btrfs]
Modules linked in: btrfs dm_thin_pool ...
CPU: 1 PID: 15884 Comm: fsx Tainted: G W 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btree_csum_one_bio+0x268/0x2d0 [btrfs]
Code: c7 c7 ...
RSP: 0018:ffffbb0109e6f8e0 EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffffe1c0847b6080 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffffaa963988 RDI: 0000000000000001
RBP: ffff956a4f4d2000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000526 R11: 0000000000000000 R12: ffff956a5cd28bb0
R13: 0000000000000000 R14: ffff956a649c9388 R15: 000000011ed82000
FS: 00007fb419959e80(0000) GS:ffff956a7aa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000fe6d54 CR3: 0000000138696005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btree_submit_bio_hook+0x67/0xc0 [btrfs]
submit_one_bio+0x31/0x50 [btrfs]
btree_write_cache_pages+0x2db/0x4b0 [btrfs]
? __filemap_fdatawrite_range+0xb1/0x110
do_writepages+0x23/0x80
__filemap_fdatawrite_range+0xd2/0x110
btrfs_write_marked_extents+0x15e/0x180 [btrfs]
btrfs_sync_log+0x206/0x10a0 [btrfs]
? kmem_cache_free+0x315/0x3b0
? btrfs_log_inode+0x1e8/0xf90 [btrfs]
? __mutex_unlock_slowpath+0x45/0x2a0
? lockref_put_or_lock+0x9/0x30
? dput+0x2d/0x580
? dput+0xb5/0x580
? btrfs_sync_file+0x464/0x4d0 [btrfs]
btrfs_sync_file+0x464/0x4d0 [btrfs]
do_fsync+0x38/0x60
__x64_sys_fsync+0x10/0x20
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb41953a6d0
Code: 48 3d ...
RSP: 002b:00007ffcc86bd218 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fb41953a6d0
RDX: 0000000000000009 RSI: 0000000000040000 RDI: 0000000000000003
RBP: 0000000000040000 R08: 0000000000000001 R09: 0000000000000009
R10: 0000000000000064 R11: 0000000000000246 R12: 0000556cf4b2c060
R13: 0000000000000100 R14: 0000000000000000 R15: 0000556cf322b420
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
softirqs last enabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
softirqs last disabled at (0): [<0000000000000000>] 0x0
---[ end trace d543fc76f5ad7fd8 ]---
In that trace the tree checker detected the overlapping checksum items at
the time when we triggered writeback for the log tree when syncing the
log.
Another trace that can happen is due to BUG_ON() when deleting checksum
items while logging an inode:
BTRFS critical (device dm-0): slot 81 key (18446744073709551606 128 13635584) new key (18446744073709551606 128 13635584)
BTRFS info (device dm-0): leaf 30949376 gen 7 total ptrs 98 free space 8527 owner 18446744073709551610
BTRFS info (device dm-0): refs 4 lock (w:1 r:0 bw:0 br:0 sw:1 sr:0) lock_owner 13473 current 13473
item 0 key (257 1 0) itemoff 16123 itemsize 160
inode generation 7 size 262144 mode 100600
item 1 key (257 12 256) itemoff 16103 itemsize 20
item 2 key (257 108 0) itemoff 16050 itemsize 53
extent data disk bytenr 13631488 nr 4096
extent data offset 0 nr 131072 ram 131072
(...)
------------[ cut here ]------------
kernel BUG at fs/btrfs/ctree.c:3153!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
CPU: 1 PID: 13473 Comm: fsx Not tainted 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_set_item_key_safe+0x1ea/0x270 [btrfs]
Code: 0f b6 ...
RSP: 0018:ffff95e3889179d0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000051 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffffb7763988 RDI: 0000000000000001
RBP: fffffffffffffff6 R08: 0000000000000000 R09: 0000000000000001
R10: 00000000000009ef R11: 0000000000000000 R12: ffff8912a8ba5a08
R13: ffff95e388917a06 R14: ffff89138dcf68c8 R15: ffff95e388917ace
FS: 00007fe587084e80(0000) GS:ffff8913baa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe587091000 CR3: 0000000126dac005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btrfs_del_csums+0x2f4/0x540 [btrfs]
copy_items+0x4b5/0x560 [btrfs]
btrfs_log_inode+0x910/0xf90 [btrfs]
btrfs_log_inode_parent+0x2a0/0xe40 [btrfs]
? dget_parent+0x5/0x370
btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
btrfs_sync_file+0x42b/0x4d0 [btrfs]
__x64_sys_msync+0x199/0x200
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fe586c65760
Code: 00 f7 ...
RSP: 002b:00007ffe250f98b8 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00000000000040e1 RCX: 00007fe586c65760
RDX: 0000000000000004 RSI: 0000000000006b51 RDI: 00007fe58708b000
RBP: 0000000000006a70 R08: 0000000000000003 R09: 00007fe58700cb61
R10: 0000000000000100 R11: 0000000000000246 R12: 00000000000000e1
R13: 00007fe58708b000 R14: 0000000000006b51 R15: 0000558de021a420
Modules linked in: dm_log_writes ...
---[ end trace c92a7f447a8515f5 ]---
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_compress_set_level() can be static function in the file
compression.c.
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>
The inode lookup starting at btrfs_iget takes the full location key,
while only the objectid is used to match the inode, because the lookup
happens inside the given root thus the inode number is unique.
The entire location key is properly set up in btrfs_init_locked_inode.
Simplify the helpers and pass only inode number, renaming it to 'ino'
instead of 'objectid'. This allows to remove temporary variables key,
saving some stack space.
Signed-off-by: David Sterba <dsterba@suse.com>
The main function to lookup a root by its id btrfs_get_fs_root takes the
whole key, while only using the objectid. The value of offset is preset
to (u64)-1 but not actually used until btrfs_find_root that does the
actual search.
Switch btrfs_get_fs_root to use only objectid and remove all local
variables that existed just for the lookup. The actual key for search is
set up in btrfs_get_fs_root, reusing another key variable.
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There are several reported runaway balance, that balance is flooding the
log with "found X extents" where the X never changes.
[CAUSE]
Commit d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after
merge_reloc_roots") introduced BTRFS_ROOT_DEAD_RELOC_TREE bit to
indicate that one subvolume has finished its tree blocks swap with its
reloc tree.
However if balance is canceled or hits ENOSPC halfway, we didn't clear
the BTRFS_ROOT_DEAD_RELOC_TREE bit, leaving that bit hanging forever
until unmount.
Any subvolume root with that bit, would cause backref cache to skip this
tree block, as it has finished its tree block swap. This would cause
all tree blocks of that root be ignored by balance, leading to runaway
balance.
[FIX]
Fix the problem by also clearing the BTRFS_ROOT_DEAD_RELOC_TREE bit for
the original subvolume of orphan reloc root.
Add an umount check for the stale bit still set.
Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When creating a snapshot, ordered extents need to be flushed and this
can take a long time.
In create_snapshot there are two locks held when this happens:
1. Destination directory inode lock
2. Global subvolume semaphore
This will unnecessarily block other operations like subvolume destroy,
create, or setflag until the snapshot is created.
We can fix that by moving the flush outside the locked section as this
does not depend on the aforementioned locks. The code factors out the
snapshot related work from create_snapshot to btrfs_mksnapshot.
__btrfs_ioctl_snap_create
btrfs_mksubvol
create_subvol
btrfs_mksnapshot
<flush>
btrfs_mksubvol
create_snapshot
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
SHAREABLE flag is set for subvolumes because users can create snapshot
for subvolumes, thus sharing tree blocks of them.
But data reloc tree is not exposed to user space, as it's only an
internal tree for data relocation, thus it doesn't need the full path
replacement handling at all.
This patch will make data reloc tree a non-shareable tree, and add
btrfs_fs_info::data_reloc_root for data reloc tree, so relocation code
can grab it from fs_info directly.
This would slightly improve tree relocation, as now data reloc tree
can go through regular COW routine to get relocated, without bothering
the complex tree reloc tree routine.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a lot of root owner checks in btrfs_truncate_inode_items()
like:
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root == fs_info->tree_root)
But considering that, only these trees can have INODE_ITEMs:
- tree root (for v1 space cache)
- subvolume trees
- tree reloc trees
- data reloc tree
- log trees
And since subvolume/tree reloc/data reloc trees all have SHAREABLE bit,
and we're checking tree root manually, so above check is just excluding
log trees.
This patch will replace two of such checks to a simpler one:
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
This would merge btrfs_drop_extent_cache() and lock_extent_bits() call
into the same if branch.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The name BTRFS_ROOT_REF_COWS is not very clear about the meaning.
In fact, that bit can only be set to those trees:
- Subvolume roots
- Data reloc root
- Reloc roots for above roots
All other trees won't get this bit set. So just by the result, it is
obvious that, roots with this bit set can have tree blocks shared with
other trees. Either shared by snapshots, or by reloc roots (an special
snapshot created by relocation).
This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to
make it easier to understand, and update all comment mentioning
"reference counted" to follow the rename.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit dccdb07bc9 ("btrfs: kill btrfs_fs_info::volume_mutex") removed
the last use of the volume_mutex, forgetting to update the comment.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The fallback path calls helper write_extent_buffer to do write of the
data spanning two extent buffer pages. As the size is known, we can do
the write directly in two steps. This removes one function call and
compiler can optimize memcpy as the sizes are known at compile time. The
cached token address is set to the second page.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper write_extent_buffer is called to do write of the data
spanning two extent buffer pages. As the size is known, we can do the
write directly in two steps. This removes one function call and
compiler can optimize memcpy as the sizes are known at compile time.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The fallback path calls helper read_extent_buffer to do read of the data
spanning two extent buffer pages. As the size is known, we can do the
read directly in two steps. This removes one function call and compiler
can optimize memcpy as the sizes are known at compile time. The cached
token address is set to the second page.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helper read_extent_buffer is called to do read of the data spanning
two extent buffer pages. As the size is known, we can do the read
directly in two steps. This removes one function call and compiler can
optimize memcpy as the sizes are known at compile time.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Helpers that iterate over extent buffer pages set up several variables,
one of them is finding out offset of the extent buffer start within a
page. Right now we have extent buffers aligned to page sizes so this is
effectively storing zero. This makes the code harder the follow and can
be simplified.
The same change is done in all the helpers:
* remove: size_t start_offset = offset_in_page(eb->start);
* simplify code using start_offset
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are many helpers around extent buffers, found in extent_io.h and
ctree.h. Most of them can be converted to take constified eb as there
are no changes to the extent buffer structure itself but rather the
pages.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All uses of map_private_extent_buffer have been replaced by more
effective way. The set/get helpers have their own bounds checker.
The function name was confusing since the non-private helper was removed
in a65917156e ("Btrfs: stop using highmem for extent_buffers") many
years ago.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The bin search jumps over the extent buffer item keys, comparing
directly the bytes if the key is in one page, or storing it in a
temporary buffer in case it spans two pages.
The mapping start and length are obtained from map_private_extent_buffer,
which is heavy weight compared to what we need. We know the key size and
can find out the eb page in a simple way. For keys spanning two pages
the fallback read_extent_buffer is used.
The temporary variables are reduced and moved to the scope of use.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The set/get token helpers either use the cached address in the token or
unconditionally call map_private_extent_buffer to get the address of
page containing the requested offset plus the mapping start and length.
Depending on the return value, the fast path uses unaligned put to write
data within a page, or fall back to write_extent_buffer that can handle
writes spanning more pages.
This is all wasteful. We know the number of bytes to write, 1/2/4/8 and
can find out the page. Then simply check if it's contained or the
fallback is needed. The token address is updated to the page, or the on
the next index, expecting that the next write will use that.
This saves one function call to map_private_extent_buffer and several
unnecessary temporary variables.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helpers unconditionally call map_private_extent_buffer to get the
address of page containing the requested offset plus the mapping start
and length. Depending on the return value, the fast path uses unaligned
put to write data within a page, or fall back to write_extent_buffer
that can handle writes spanning more pages.
This is all wasteful. We know the number of bytes to write, 1/2/4/8 and
can find out the page. Then simply check if it's contained or the
fallback is needed.
This saves one function call to map_private_extent_buffer and several
unnecessary temporary variables.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The set/get token helpers either use the cached address in the token or
unconditionally call map_private_extent_buffer to get the address of
page containing the requested offset plus the mapping start and length.
Depending on the return value, the fast path uses unaligned read to get
data within a page, or fall back to read_extent_buffer that can handle
reads spanning more pages.
This is all wasteful. We know the number of bytes to read, 1/2/4/8 and
can find out the page. Then simply check if it's contained or the
fallback is needed. The token address is updated to the page, or the on
the next index, expecting that the next read will use that.
This saves one function call to map_private_extent_buffer and several
unnecessary temporary variables.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helpers unconditionally call map_private_extent_buffer to get the
address of page containing the requested offset plus the mapping start
and length. Depending on the return value, the fast path uses unaligned
read to get data within a page, or fall back to read_extent_buffer that
can handle reads spanning more pages.
This is all wasteful. We know the number of bytes to read, 1/2/4/8 and
can find out the page. Then simply check if it's contained or the
fallback is needed.
This saves one function call to map_private_extent_buffer and several
unnecessary temporary variables.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The bounds checking is now done in map_private_extent_buffer but that
will be removed in following patches and some sanity checks should still
be done.
There are two separate checks to see the kind of out of bounds access:
partial (start offset is in the buffer) or complete (both start and end
are out).
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All the set/get helpers first check if the token contains a cached
address. After first use the address is always valid, but the extra
check is done for each call.
The token initialization can optimistically set it to the first extent
buffer page, that we know always exists. Then the condition in all
btrfs_token_*/btrfs_set_token_* can be simplified by removing the
address check from the condition, but for development the assertion
still makes sure it's valid.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The token is supposed to cache the last page used by the set/get
helpers. In leaf_space_used the first and last items are accessed, it's
not likely they'd be on the same page so there's some overhead caused
updating the token address but not using it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The set/get token is supposed to cache the last page that was accessed
so it speeds up subsequential access to the eb. It does not make sense
to use that for just one change, which is the case of inode size in
overwrite_item.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all set/get helpers use the eb from the token, we don't need to
pass it to many btrfs_token_*/btrfs_set_token_* helpers, saving some
stack space.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The token stores a copy of the extent buffer pointer but does not make
any use of it besides sanity checks. We can use it and drop the eb
parameter from several functions, this patch only switches the use
inside the set/get helpers.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
disk-io.h is included more than once in block-group.c, remove it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: David Sterba <dsterba@suse.com>
The name of this function contains the word "cache", which is left from
the times where btrfs_block_group was called btrfs_block_group_cache.
Now this "cache" doesn't match anything, and we have better namings for
functions like read/insert/remove_block_group_item().
Rename it to update_block_group_item().
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>
Currently the block group item insert is pretty straight forward, fill
the block group item structure and insert it into extent tree.
However the incoming skinny block group feature is going to change this,
so this patch will refactor insertion into a new function,
insert_block_group_item(), to make the incoming feature easier to add.
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>
When deleting a block group item, it's pretty straight forward, just
delete the item pointed by the key. However it will not be that
straight-forward for incoming skinny block group item.
So refactor the block group item deletion into a new function,
remove_block_group_item(), also to make the already lengthy
btrfs_remove_block_group() a little shorter.
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>
Structure btrfs_block_group has the following members which are
currently read from on-disk block group item and key:
- length - from item key
- used
- flags - from block group item
However for incoming skinny block group tree, we are going to read those
members from different sources.
This patch will refactor such read by:
- Don't initialize btrfs_block_group::length at allocation
Caller should initialize them manually.
Also to avoid possible (well, only two callers) missing
initialization, add extra ASSERT() in btrfs_add_block_group_cache().
- Refactor length/used/flags initialization into one function
The new function, fill_one_block_group() will handle the
initialization of such members.
- Use btrfs_block_group::length to replace key::offset
Since skinny block group item would have a different meaning for its
key offset.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Regular block group items in extent tree are scattered inside the huge
tree, thus forward readahead makes no sense.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever a chown is executed, all capabilities of the file being touched
are lost. When doing incremental send with a file with capabilities,
there is a situation where the capability can be lost on the receiving
side. The sequence of actions bellow shows the problem:
$ mount /dev/sda fs1
$ mount /dev/sdb fs2
$ touch fs1/foo.bar
$ setcap cap_sys_nice+ep fs1/foo.bar
$ btrfs subvolume snapshot -r fs1 fs1/snap_init
$ btrfs send fs1/snap_init | btrfs receive fs2
$ chgrp adm fs1/foo.bar
$ setcap cap_sys_nice+ep fs1/foo.bar
$ btrfs subvolume snapshot -r fs1 fs1/snap_complete
$ btrfs subvolume snapshot -r fs1 fs1/snap_incremental
$ btrfs send fs1/snap_complete | btrfs receive fs2
$ btrfs send -p fs1/snap_init fs1/snap_incremental | btrfs receive fs2
At this point, only a chown was emitted by "btrfs send" since only the
group was changed. This makes the cap_sys_nice capability to be dropped
from fs2/snap_incremental/foo.bar
To fix that, only emit capabilities after chown is emitted. The current
code first checks for xattrs that are new/changed, emits them, and later
emit the chown. Now, __process_new_xattr skips capabilities, letting
only finish_inode_if_needed to emit them, if they exist, for the inode
being processed.
This behavior was being worked around in "btrfs receive" side by caching
the capability and only applying it after chown. Now, xattrs are only
emmited _after_ chown, making that workaround not needed anymore.
Link: https://github.com/kdave/btrfs-progs/issues/202
CC: stable@vger.kernel.org # 4.4+
Suggested-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When scrubbing a stripe, whenever we find an extent we lookup for its
checksums in the checksum tree. However we do it even for metadata extents
which don't have checksum items stored in the checksum tree, that is
only for data extents.
So make the lookup for checksums only if we are processing with a data
extent.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The helpers btrfs_freeze_block_group() and btrfs_unfreeze_block_group()
used to be named btrfs_get_block_group_trimming() and
btrfs_put_block_group_trimming() respectively.
At the time they were added to free-space-cache.c, by commit e33e17ee10
("btrfs: add missing discards when unpinning extents with -o discard")
because all the trimming related functions were in free-space-cache.c.
Now that the helpers were renamed and are used in scrub context as well,
move them to block-group.c, a much more logical location for them.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Back in 2014, commit 04216820fe ("Btrfs: fix race between fs trimming
and block group remove/allocation"), I added the 'trimming' member to the
block group structure. Its purpose was to prevent races between trimming
and block group deletion/allocation by pinning the block group in a way
that prevents its logical address and device extents from being reused
while trimming is in progress for a block group, so that if another task
deletes the block group and then another task allocates a new block group
that gets the same logical address and device extents while the trimming
task is still in progress.
After the previous fix for scrub (patch "btrfs: fix a race between scrub
and block group removal/allocation"), scrub now also has the same needs that
trimming has, so the member name 'trimming' no longer makes sense.
Since there is already a 'pinned' member in the block group that refers
to space reservations (pinned bytes), rename the member to 'frozen',
add a comment on top of it to describe its general purpose and rename
the helpers to increment and decrement the counter as well, to match
the new member name.
The next patch in the series will move the helpers into a more suitable
file (from free-space-cache.c to block-group.c).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When scrub is verifying the extents of a block group for a device, it is
possible that the corresponding block group gets removed and its logical
address and device extents get used for a new block group allocation.
When this happens scrub incorrectly reports that errors were detected
and, if the the new block group has a different profile then the old one,
deleted block group, we can crash due to a null pointer dereference.
Possibly other unexpected and weird consequences can happen as well.
Consider the following sequence of actions that leads to the null pointer
dereference crash when scrub is running in parallel with balance:
1) Balance sets block group X to read-only mode and starts relocating it.
Block group X is a metadata block group, has a raid1 profile (two
device extents, each one in a different device) and a logical address
of 19424870400;
2) Scrub is running and finds device extent E, which belongs to block
group X. It enters scrub_stripe() to find all extents allocated to
block group X, the search is done using the extent tree;
3) Balance finishes relocating block group X and removes block group X;
4) Balance starts relocating another block group and when trying to
commit the current transaction as part of the preparation step
(prepare_to_relocate()), it blocks because scrub is running;
5) The scrub task finds the metadata extent at the logical address
19425001472 and marks the pages of the extent to be read by a bio
(struct scrub_bio). The extent item's flags, which have the bit
BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct
scrub_page). It is these flags in the scrub pages that tells the
bio's end io function (scrub_bio_end_io_worker) which type of extent
it is dealing with. At this point we end up with 4 pages in a bio
which is ready for submission (the metadata extent has a size of
16Kb, so that gives 4 pages on x86);
6) At the next iteration of scrub_stripe(), scrub checks that there is a
pause request from the relocation task trying to commit a transaction,
therefore it submits the pending bio and pauses, waiting for the
transaction commit to complete before resuming;
7) The relocation task commits the transaction. The device extent E, that
was used by our block group X, is now available for allocation, since
the commit root for the device tree was swapped by the transaction
commit;
8) Another task doing a direct IO write allocates a new data block group Y
which ends using device extent E. This new block group Y also ends up
getting the same logical address that block group X had: 19424870400.
This happens because block group X was the block group with the highest
logical address and, when allocating Y, find_next_chunk() returns the
end offset of the current last block group to be used as the logical
address for the new block group, which is
18351128576 + 1073741824 = 19424870400
So our new block group Y has the same logical address and device extent
that block group X had. However Y is a data block group, while X was
a metadata one, and Y has a raid0 profile, while X had a raid1 profile;
9) After allocating block group Y, the direct IO submits a bio to write
to device extent E;
10) The read bio submitted by scrub reads the 4 pages (16Kb) from device
extent E, which now correspond to the data written by the task that
did a direct IO write. Then at the end io function associated with
the bio, scrub_bio_end_io_worker(), we call scrub_block_complete()
which calls scrub_checksum(). This later function checks the flags
of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK
is set in the flags, so it assumes it has a metadata extent and
then calls scrub_checksum_tree_block(). That functions returns an
error, since interpreting data as a metadata extent causes the
checksum verification to fail.
So this makes scrub_checksum() call scrub_handle_errored_block(),
which determines 'failed_mirror_index' to be 1, since the device
extent E was allocated as the second mirror of block group X.
It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at
'sblocks_for_recheck', and all the memory is initialized to zeroes by
kcalloc().
After that it calls scrub_setup_recheck_block(), which is responsible
for filling each of those structures. However, when that function
calls btrfs_map_sblock() against the logical address of the metadata
extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches
the current block group Y. However block group Y has a raid0 profile
and not a raid1 profile like X had, so the following call returns 1:
scrub_nr_raid_mirrors(bbio)
And as a result scrub_setup_recheck_block() only initializes the
first (index 0) scrub_block structure in 'sblocks_for_recheck'.
Then scrub_recheck_block() is called by scrub_handle_errored_block()
with the second (index 1) scrub_block structure as the argument,
because 'failed_mirror_index' was previously set to 1.
This scrub_block was not initialized by scrub_setup_recheck_block(),
so it has zero pages, its 'page_count' member is 0 and its 'pagev'
page array has all members pointing to NULL.
Finally when scrub_recheck_block() calls scrub_recheck_block_checksum()
we have a NULL pointer dereference when accessing the flags of the first
page, as pavev[0] is NULL:
static void scrub_recheck_block_checksum(struct scrub_block *sblock)
{
(...)
if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
scrub_checksum_data(sblock);
(...)
}
Producing a stack trace like the following:
[542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028
[542998.010238] #PF: supervisor read access in kernel mode
[542998.010878] #PF: error_code(0x0000) - not-present page
[542998.011516] PGD 0 P4D 0
[542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1
[542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs]
[542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs]
[542998.018474] Code: 4c 89 e6 ...
[542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202
[542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000
[542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120
[542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001
[542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800
[542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0
[542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000
[542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0
[542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[542998.032380] Call Trace:
[542998.032752] scrub_recheck_block+0x162/0x400 [btrfs]
[542998.033500] ? __alloc_pages_nodemask+0x31e/0x460
[542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs]
[542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs]
[542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs]
[542998.036735] process_one_work+0x26d/0x6a0
[542998.037275] worker_thread+0x4f/0x3e0
[542998.037740] ? process_one_work+0x6a0/0x6a0
[542998.038378] kthread+0x103/0x140
[542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70
[542998.039419] ret_from_fork+0x3a/0x50
[542998.039875] Modules linked in: dm_snapshot dm_thin_pool ...
[542998.047288] CR2: 0000000000000028
[542998.047724] ---[ end trace bde186e176c7f96a ]---
This issue has been around for a long time, possibly since scrub exists.
The last time I ran into it was over 2 years ago. After recently fixing
fstests to pass the "--full-balance" command line option to btrfs-progs
when doing balance, several tests started to more heavily exercise balance
with fsstress, scrub and other operations in parallel, and therefore
started to hit this issue again (with btrfs/061 for example).
Fix this by having scrub increment the 'trimming' counter of the block
group, which pins the block group in such a way that it guarantees neither
its logical address nor device extents can be reused by future block group
allocations until we decrement the 'trimming' counter. Also make sure that
on each iteration of scrub_stripe() we stop scrubbing the block group if
it was removed already.
A later patch in the series will rename the block group's 'trimming'
counter and its helpers to a more generic name, since now it is not used
exclusively for pinning while trimming anymore.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The extent references v0 have been superseded long time go, there are
some unused declarations of access helpers. We can safely remove them
now. The struct btrfs_extent_ref_v0 is not used anywhere, but struct
btrfs_extent_item_v0 is still part of a backward compatibility check in
relocation.c and thus not removed.
Signed-off-by: David Sterba <dsterba@suse.com>
There's no callers in-tree anymore since
commit d24ee97b96 ("btrfs: use new helpers to set uuids in eb")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
For the following operation, qgroup is guaranteed to be screwed up due
to snapshot adding to a new qgroup:
# mkfs.btrfs -f $dev
# mount $dev $mnt
# btrfs qgroup en $mnt
# btrfs subv create $mnt/src
# xfs_io -f -c "pwrite 0 1m" $mnt/src/file
# sync
# btrfs qgroup create 1/0 $mnt/src
# btrfs subv snapshot -i 1/0 $mnt/src $mnt/snapshot
# btrfs qgroup show -prce $mnt/src
qgroupid rfer excl max_rfer max_excl parent child
-------- ---- ---- -------- -------- ------ -----
0/5 16.00KiB 16.00KiB none none --- ---
0/257 1.02MiB 16.00KiB none none --- ---
0/258 1.02MiB 16.00KiB none none 1/0 ---
1/0 0.00B 0.00B none none --- 0/258
^^^^^^^^^^^^^^^^^^^^
[CAUSE]
The problem is in btrfs_qgroup_inherit(), we don't have good enough
check to determine if the new relation would break the existing
accounting.
Unlike btrfs_add_qgroup_relation(), which has proper check to determine
if we can do quick update without a rescan, in btrfs_qgroup_inherit() we
can even assign a snapshot to multiple qgroups.
[FIX]
Fix it by manually marking qgroup inconsistent for snapshot inheritance.
For subvolume creation, since all its extents are exclusively owned, we
don't need to rescan.
In theory, we should call relation check like quick_update_accounting()
when doing qgroup inheritance and inform user about qgroup accounting
inconsistency.
But we don't have good mechanism to relay that back to the user in the
snapshot creation context, thus we can only silently mark the qgroup
inconsistent.
Anyway, user shouldn't use qgroup inheritance during snapshot creation,
and should add qgroup relationship after snapshot creation by 'btrfs
qgroup assign', which has a much better UI to inform user about qgroup
inconsistent and kick in rescan automatically.
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>
When mounting, we handle deleted subvolume and orphan items. First,
find add orphan roots, then add them to fs_root radix tree. Second, in
tree-root, process each orphan item, skip if it is dead root.
The original algorithm is based on the list of dead_roots, one by one to
visit and check whether the objectid is consistent, the time complexity
is O (n ^ 2). When processing 50000 deleted subvols, it takes about
120s.
Because btrfs_find_orphan_roots has already ran before us, and added
deleted subvol to fs_roots radix tree.
The fs root will only be removed from the fs_roots radix tree after the
cleaner process is started, and the cleaner will only start execution
after the mount is complete.
btrfs_orphan_cleanup can be called during the whole filesystem mount
lifetime, but only "tree root" will be used in this section of code, and
only mount time will be brought into tree root.
So we can quickly check whether the orphan item is dead root through the
fs_roots radix tree.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I've grepped logs for 'errno=.*unknown' and found -95, -117 and -122,
now added to the table. The wording is adjusted so it makes sense in
context of filesystem.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When an old device has new fsid through 'btrfs device add -f <dev>' our
fs_devices list has an alien device in one of the fs_devices lists.
By having an alien device in fs_devices, we have two issues so far
1. missing device does not not show as missing in the userland
2. degraded mount will fail
Both issues are caused by the fact that there's an alien device in the
fs_devices list. (Alien means that it does not belong to the filesystem,
identified by fsid, or does not contain btrfs filesystem at all, eg. due
to overwrite).
A device can be scanned/added through the control device ioctls
SCAN_DEV, DEVICES_READY or by ADD_DEV.
And device coming through the control device is checked against the all
other devices in the lists, but this was not the case for ADD_DEV.
This patch fixes both issues above by removing the alien device.
CC: stable@vger.kernel.org # 5.4+
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_free_extra_devids() updates fs_devices::latest_bdev to point to
the bdev with greatest device::generation number. For a typical-missing
device the generation number is zero so fs_devices::latest_bdev will
never point to it.
But if the missing device is due to alienation [1], then
device::generation is not zero and if it is greater or equal to the rest
of device generations in the list, then fs_devices::latest_bdev ends up
pointing to the missing device and reports the error like [2].
[1] We maintain devices of a fsid (as in fs_device::fsid) in the
fs_devices::devices list, a device is considered as an alien device
if its fsid does not match with the fs_device::fsid
Consider a working filesystem with raid1:
$ mkfs.btrfs -f -d raid1 -m raid1 /dev/sda /dev/sdb
$ mount /dev/sda /mnt-raid1
$ umount /mnt-raid1
While mnt-raid1 was unmounted the user force-adds one of its devices to
another btrfs filesystem:
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt-single
$ btrfs dev add -f /dev/sda /mnt-single
Now the original mnt-raid1 fails to mount in degraded mode, because
fs_devices::latest_bdev is pointing to the alien device.
$ mount -o degraded /dev/sdb /mnt-raid1
[2]
mount: wrong fs type, bad option, bad superblock on /dev/sdb,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
kernel: BTRFS warning (device sdb): devid 1 uuid 072a0192-675b-4d5a-8640-a5cf2b2c704d is missing
kernel: BTRFS error (device sdb): failed to read devices
kernel: BTRFS error (device sdb): open_ctree failed
Fix the root cause by checking if the device is not missing before it
can be considered for the fs_devices::latest_bdev.
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.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>
Use crypto_shash_digest() instead of crypto_shash_init() +
crypto_shash_update() + crypto_shash_final(). This is more efficient.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no need of goto out in open_fs_devices() as there is nothing
special done there.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.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>
At btrfs_log_prealloc_extents() we are checking if copy_items() returns a
value greater than 0. That used to happen in the past to signal the caller
that the path given to it was released and reused for other searches, but
as of commit 0e56315ca1 ("Btrfs: fix missing hole after hole punching
and fsync when using NO_HOLES"), the copy_items() function does not have
that behaviour anymore and always returns 0 or a negative value. So just
remove that check at btrfs_log_prealloc_extents(), which the previously
mentioned commit forgot to remove.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, direct I/O has its own versions of bio_readpage_error() and
btrfs_check_repairable() (dio_read_error() and
btrfs_check_dio_repairable(), respectively). The main difference is that
the direct I/O version doesn't do read validation. The rework of direct
I/O repair makes it possible to do validation, so we can get rid of
btrfs_check_dio_repairable() and combine bio_readpage_error() and
dio_read_error() into a new helper, btrfs_submit_read_repair().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This was originally added in commit 8b110e393c ("Btrfs: implement
repair function when direct read fails") to avoid a deadlock. In that
commit, the direct I/O read endio executes on the endio_workers
workqueue, submits a repair bio, and waits for it to complete. The
repair bio endio must execute on a different workqueue, otherwise it
could block on the endio_workers workqueue becoming available, which
won't happen because the original endio is blocked on the repair bio.
As of the previous commit, the original endio doesn't wait for the
repair bio, so this separate workqueue is unnecessary.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Direct I/O read repair was originally implemented in commit 8b110e393c
("Btrfs: implement repair function when direct read fails"). This
implementation is unnecessarily complicated. There is major code
duplication between __btrfs_subio_endio_read() (checks checksums and
handles I/O errors for files with checksums),
__btrfs_correct_data_nocsum() (handles I/O errors for files without
checksums), btrfs_retry_endio() (checks checksums and handles I/O errors
for retries of files with checksums), and btrfs_retry_endio_nocsum()
(handles I/O errors for retries of files without checksum). If it sounds
like these should be one function, that's because they should.
Additionally, these functions are very hard to follow due to their
excessive use of goto.
This commit replaces the original implementation. After the previous
commit getting rid of orig_bio, we can reuse the same endio callback for
repair I/O and the original I/O, we just need to track the file offset
and original iterator in the repair bio. We can also unify the handling
of files with and without checksums and simplify the control flow. We
also no longer have to wait for each repair I/O to complete one by one.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the worst case, there are _4_ layers of bios in the Btrfs direct I/O
path:
1. The bio created by the generic direct I/O code (dio_bio).
2. A clone of dio_bio we create in btrfs_submit_direct() to represent
the entire direct I/O range (orig_bio).
3. A partial clone of orig_bio limited to the size of a RAID stripe that
we create in btrfs_submit_direct_hook().
4. Clones of each of those split bios for each RAID stripe that we
create in btrfs_map_bio().
As of the previous commit, the second layer (orig_bio) is no longer
needed for anything: we can split dio_bio instead, and complete dio_bio
directly when all of the cloned bios complete. This lets us clean up a
bunch of cruft, including dip->subio_endio and dip->errors (we can use
dio_bio->bi_status instead). It also enables the next big cleanup of
direct I/O read repair.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The next commit will get rid of btrfs_dio_private->orig_bio. The only
thing we really need it for is containing all of the checksums, but we
can easily put the checksum array in btrfs_dio_private and have the
submitted bios reference the array. We can also look the checksums up
while we're setting up instead of the current awkward logic that looks
them up for orig_bio when the first split bio is submitted.
(Interestingly, btrfs_dio_private did contain the
checksums before commit 23ea8e5a07 ("Btrfs: load checksum data once
when submitting a direct read io"), but it didn't look them up up
front.)
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is really a reference count now, so convert it to refcount_t and
rename it to refs.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We haven't used this since commit 9be3395bcd ("Btrfs: use a btrfs
bioset instead of abusing bio internals").
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since its introduction in commit 2fe6303e7c ("Btrfs: split
bio_readpage_error into several functions"), btrfs_check_repairable()
has only been used from extent_io.c where it is defined.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
__readpage_endio_check() is also used from the direct I/O read code, so
give it a more descriptive name.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fix a couple of issues in the btrfs_lookup_bio_sums documentation:
* The bio doesn't need to be a btrfs_io_bio if dst was provided. Move
the declaration in the code to make that clear, too.
* dst must be large enough to hold nblocks * csum_size, not just
csum_size.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The purpose of the validation step is to distinguish between good and
bad sectors in a failed multi-sector read. If a multi-sector read
succeeded but some of those sectors had checksum errors, we don't need
to validate anything; we know the sectors with bad checksums need to be
repaired.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
