In the patch a2c8d27e5e ("btrfs: use a structure to pass arguments to
backref walking functions") Filipe converted everybody to using a new
context struct to use for backref lookups, but accidentally dropped the
BTRFS_SEQ_LAST usage that exists for qgroups. Add this back so we have
the previous behavior.
Fixes: a2c8d27e5e ("btrfs: use a structure to pass arguments to backref walking functions")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When removing the btrfs module we are not calling btrfs_cleanup_fs_uuids()
which results in leaking btrfs_fs_devices structures and other resources.
This is a regression recently introduced by a refactoring of the module
initialization and exit sequence, which simply removed the call to
btrfs_cleanup_fs_uuids() in the exit path, resulting in the leaks.
So fix this by calling btrfs_cleanup_fs_uuids() at exit_btrfs_fs().
Fixes: 5565b8e0ad ("btrfs: make module init/exit match their sequence")
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>
All error handling paths end to 'out', except this memory allocation
failure.
This is spurious. So branch to the error handling path also in this case.
It will add a call to:
memset(&root->defrag_progress, 0,
sizeof(root->defrag_progress));
Fixes: 6702ed490c ("Btrfs: Add run time btree defrag, and an ioctl to force btree defrag")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If new_whiteout_inode() fails, some resources need to be freed.
Add the missing goto to the error handling path.
Fixes: ab3c5c18e8 ("btrfs: setup qstr from dentrys using fscrypt helper")
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we print the transaction aborted message with a debug level, but
a transaction abort is an exceptional event that indicates something went
wrong and it's useful to have it printed with an error level as it helps
analysing problems in a production environment, where debug level messages
are typically not logged. For example reports from syzbot never include
the transaction aborted message, since the log level on the test machines
is above the debug level.
So change the log level from debug to error.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
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>
If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.
Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.
So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.
Reported-by: syzbot+0b1fb6b0108c27419f9f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@google.com/
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>
Store the error code before freeing the extent_map. Though it's
reference counted structure, in that function it's the first and last
allocation so this would lead to a potential use-after-free.
The error can happen eg. when chunk is stored on a missing device and
the degraded mount option is missing.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216721
Reported-by: eriri <1527030098@qq.com>
Fixes: adfb69af7d ("btrfs: add_missing_dev() should return the actual error")
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: void0red <void0red@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
As of commit 193df62457 ("btrfs: search for last logged dir index if
it's not cached in the inode"), the overwrite_item() function is always
called for a root that is from a fs/subvolume tree. In other words, now
it's only used during log replay to modify a fs/subvolume tree. Therefore
we can remove the logic that checks if we are dealing with a log tree at
overwrite_item().
So remove that logic, replacing it with an assertion and document that if
we ever need to support a log root there, we will need to clone the leaf
from the fs/subvolume tree and then release it before modifying the log
tree, which is needed to avoid a potential deadlock, similar to the one
recently fixed by a patch with the subject:
"btrfs: do not modify log tree while holding a leaf from fs tree locked"
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>
After commit 193df62457 ("btrfs: search for last logged dir index if
it's not cached in the inode"), there are no more callers of
do_overwrite_item(), except overwrite_item().
Originally both used to be the same function, but were split in
commit 086dcbfa50 ("btrfs: insert items in batches when logging a
directory when possible"), as there was the need to execute all logic
of overwrite_item() but skip the tree search, since in the context of
directory logging we already had a path with a leaf to copy data from.
So unify them again as there is no more need to have them split.
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>
Using strncpy() on NUL-terminated strings are deprecated. To avoid
possible forming of non-terminated string strscpy() should be used.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This was caught when syncing extent-io-tree.c into btrfs-progs. This
however isn't really a problem, the only way next would be uninitialized
is if we found the range we were looking for, and in this case we don't
care about next. However it's a compile error, so fix it up.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I don't know how this isn't caught when we build this in the kernel, but
while syncing extent-io-tree.c into btrfs-progs I got an error because
parent could potentially be uninitialized when we link in a new node,
specifically when the extent_io_tree is empty. This means we could have
garbage in the parent color. I don't know what the ramifications are of
that, but it's probably not great, so fix this by initializing parent to
NULL. I spot checked all of our other usages in btrfs and we appear to
be doing the correct thing everywhere else.
Fixes: c7e118cf98 ("btrfs: open code rbtree search in insert_state")
CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add annotations to functions that might sleep due to allocations or IO
and could be called from various contexts. In case of btrfs_search_slot
it's not obvious why it would sleep:
btrfs_search_slot
setup_nodes_for_search
reada_for_balance
btrfs_readahead_node_child
btrfs_readahead_tree_block
btrfs_find_create_tree_block
alloc_extent_buffer
kmem_cache_zalloc
/* allocate memory non-atomically, might sleep */
kmem_cache_alloc(GFP_NOFS|__GFP_NOFAIL|__GFP_ZERO)
read_extent_buffer_pages
submit_extent_page
/* disk IO, might sleep */
submit_one_bio
Other examples where the sleeping could happen is in 3 places might
sleep in update_qgroup_limit_item(), as shown below:
update_qgroup_limit_item
btrfs_alloc_path
/* allocate memory non-atomically, might sleep */
kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS)
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't have these defined in the kernel because we don't have any
users of these helpers. However we do use them in btrfs-progs, so
define them to make keeping accessors.h in sync between progs and the
kernel easier.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We already have this defined in btrfs-progs, add it to the kernel to
make it easier to sync these files into btrfs-progs.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is simply the same thing as btrfs_item_nr_offset(leaf, 0), so
remove this helper and replace it's usage with the above statement.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have some gnarly memmove and copy_extent_buffer calls for leaf
manipulation. This is because our item offsets aren't absolute, they're
based on 0 being where the items start in the leaf, which is after the
btrfs_header. This means any manipulation of the data requires adding
sizeof(struct btrfs_header) to the offsets we pull from the items.
Moving the items themselves is easier as the helpers are absolute
offsets, however we of course have to call the helpers to get the
offsets for the item numbers. This makes for
copy_extent_buffer/memmove_extent_buffer calls that are kind of hard to
reason about what's happening.
Fix this by pushing this logic into helpers. For data we'll only use
the item provided offsets, and the helpers will use the
BTRFS_LEAF_DATA_OFFSET addition for the offsets. Additionally for the
item manipulation simply pass in the item numbers, and then the helpers
will call the offset helper to get the actual offset into the leaf.
The diffstat makes this look like more code, but that's simply because I
added comments for the helpers, it's net negative for the amount of
code, and is easier to reason.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a change needed for extent tree v2, as we will be growing the
header size. This exists in btrfs-progs currently, and not having it
makes syncing accessors.[ch] more problematic. So make this change to
set us up for extent tree v2 and match what btrfs-progs does to make
syncing easier.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is actually a change for extent tree v2, but it exists in
btrfs-progs but not in the kernel. This makes it annoying to sync
accessors.h with btrfs-progs, and since this is the way I need it for
extent-tree v2 simply update these helpers to take the extent buffer in
order to make syncing possible now, and make the extent tree v2 stuff
easier moving forward.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These got moved because of copy+paste, but this code exists in ctree.c,
so move the declarations back into ctree.h.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These are very specific to how the extent buffer is defined, so this
differs between btrfs-progs and the kernel. Make things easier by
moving these helpers into extent_io.h so we don't have to worry about
this when syncing ctree.h.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These helpers use functions that are in multiple places, which makes it
tricky to sync them into btrfs-progs. Move them to file-item.h and then
include file-item.h in places that use these helpers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is only used in ctree.c, with the exception of zero'ing out extent
buffers we're getting ready to write out. In theory we shouldn't have
an extent buffer with 0 items that we're writing out, however I'd rather
be safe than sorry so open code it in extent_io.c, and then copy the
helper into ctree.c. This will make it easier to sync accessors.[ch]
into btrfs-progs, as this requires a helper that isn't defined in
accessors.h.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These accidentally got brought into accessors.h, but belong with the
btrfs_root definitions which are currently in ctree.h. Move these to
make it easier to sync accessors.[ch] into btrfs-progs.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
repair_io_failure ties directly into all the glory low-level details of
mapping a bio with a logic address to the actual physical location.
Move it right below btrfs_submit_bio to keep all the related logic
together.
Also move btrfs_repair_eb_io_failure to its caller in disk-io.c now that
repair_io_failure is available in a header.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The code used by btrfs_submit_bio only interacts with the rest of
volumes.c through __btrfs_map_block (which itself is a more generic
version of two exported helpers) and does not really have anything
to do with volumes.c. Create a new bio.c file and a bio.h header
going along with it for the btrfs_bio-based storage layer, which
will grow even more going forward.
Also update the file with my copyright notice given that a large
part of the moved code was written or rewritten by me.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
an various .c files don't have to include disk-io.h just for it.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
[ use tree-checker.h for the structure ]
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
For the following small script, btrfs will be unable to recover the
content of file1:
mkfs.btrfs -f -m raid1 -d raid5 -b 1G $dev1 $dev2 $dev3
mount $dev1 $mnt
xfs_io -f -c "pwrite -S 0xff 0 64k" -c sync $mnt/file1
md5sum $mnt/file1
umount $mnt
# Corrupt the above 64K data stripe.
xfs_io -f -c "pwrite -S 0x00 323026944 64K" -c sync $dev3
mount $dev1 $mnt
# Write a new 64K, which should be in the other data stripe
# And this is a sub-stripe write, which will cause RMW
xfs_io -f -c "pwrite 0 64k" -c sync $mnt/file2
md5sum $mnt/file1
umount $mnt
Above md5sum would fail.
[CAUSE]
There is a long existing problem for raid56 (not limited to btrfs
raid56) that, if we already have some corrupted on-disk data, and then
trigger a sub-stripe write (which needs RMW cycle), it can cause further
damage into P/Q stripe.
Disk 1: data 1 |0x000000000000| <- Corrupted
Disk 2: data 2 |0x000000000000|
Disk 2: parity |0xffffffffffff|
In above case, data 1 is already corrupted, the original data should be
64KiB of 0xff.
At this stage, if we read data 1, and it has data checksum, we can still
recovery going via the regular RAID56 recovery path.
But if now we decide to write some data into data 2, then we need to go
RMW.
Let's say we want to write 64KiB of '0x00' into data 2, then we read the
on-disk data of data 1, calculate the new parity, resulting the
following layout:
Disk 1: data 1 |0x000000000000| <- Corrupted
Disk 2: data 2 |0x000000000000| <- New '0x00' writes
Disk 2: parity |0x000000000000| <- New Parity.
But the new parity is calculated using the *corrupted* data 1, we can
no longer recover the correct data of data1. Thus the corruption is
forever there.
[FIX]
To solve above problem, this patch will do a full stripe data checksum
verification at RMW time.
This involves the following changes:
- Always read the full stripe (including data/P/Q) when doing RMW
Before we only read the missing data sectors, but since we may do a
data csum verification and recovery, we need to read everything out.
Please note that, if we have a cached rbio, we don't need to read
anything, and can treat it the same as full stripe write.
As only stripe with all its csum matches can be cached.
- Verify the data csum during read.
The goal is only the rbio stripe sectors, and only if the rbio
already has csum_buf/csum_bitmap filled.
And sectors which cannot pass csum verification will have their bit
set in error_bitmap.
- Always call recovery_sectors() after we read out all the sectors
Since error_bitmap will be updated during read, recover_sectors()
can easily find out all the bad sectors and try to recover (if still
under tolerance).
And since recovery_sectors() is already migrated to use error_bitmap,
it can skip vertical stripes which don't have any error.
- Verify the repaired sectors against its csum in recover_vertical()
- Rename rmw_read_and_wait() to rmw_read_wait_recover()
Since we will always recover the sectors, the old name is no longer
accurate.
Furthermore since recovery is already done in rmw_read_wait_recover(),
we no longer need to call recovery_sectors() inside rmw_rbio().
Obviously this will have a performance impact, as we are doing more
work during RMW cycle:
- Fetch the data checksums
- Do checksum verification for all data stripes
- Do checksum verification again after repair
But for full stripe write or cached rbio we won't have the overhead all,
thus for fully optimized RAID56 workload (always full stripe write),
there should be no extra overhead.
To me, the extra overhead looks reasonable, as data consistency is way
more important than performance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is for later data checksum verification at RMW time.
This patch will try to allocate the needed memory for a locked rbio if
the rbio is for data exclusively (we don't want to handle mixed bg yet).
The memory will be released when the rbio is finished.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although we have an existing function, btrfs_lookup_csums_range(), to
find all data checksums for a range, it's based on a btrfs_ordered_sum
list.
For the incoming RAID56 data checksum verification at RMW time, we don't
want to waste time by allocating temporary memory.
So this patch will introduce a new helper, btrfs_lookup_csums_bitmap().
It will use bitmap based result, which will be a perfect fit for later
RAID56 usage.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The refactoring involves the following parts:
- Introduce bytes_to_csum_size() and csum_size_to_bytes() helpers
As we have quite some open-coded calculations, some of them are even
split into two assignments just to fit 80 chars limit.
- Remove the @csum_size parameter from max_ordered_sum_bytes()
Csum size can be fetched from @fs_info.
And we will use the csum_size_to_bytes() helper anyway.
- Add a comment explaining how we handle the first search result
- Use newly introduced helpers to cleanup btrfs_lookup_csums_range()
- Move variables declaration to the minimal scope
- Never mix number of sectors with bytes
There are several locations doing things like:
size = min_t(size_t, csum_end - start,
max_ordered_sum_bytes(fs_info));
...
size >>= fs_info->sectorsize_bits
Or
offset = (start - key.offset) >> fs_info->sectorsize_bits;
offset *= csum_size;
Make sure these variables can only represent BYTES inside the
function, by using the above bytes_to_csum_size() helpers.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The __GFP_NOFAIL flag could loop indefinitely when allocation memory in
alloc_btrfs_io_context. The callers starting from __btrfs_map_block
already handle errors so it's safe to drop the flag.
Signed-off-by: Li zeming <zeming@nfschina.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If dev-replace failed to re-construct its data/metadata, the kernel
message would be incorrect for the missing device:
BTRFS info (device dm-1): dev_replace from <missing disk> (devid 2) to /dev/mapper/test-scratch2 started
BTRFS error (device dm-1): failed to rebuild valid logical 38862848 for dev (efault)
Note the above "dev (efault)" of the second line.
While the first line is properly reporting "<missing disk>".
[CAUSE]
Although dev-replace is using btrfs_dev_name(), the heavy lifting work
is still done by scrub (scrub is reused by both dev-replace and regular
scrub).
Unfortunately scrub code never uses btrfs_dev_name() helper, as it's
only declared locally inside dev-replace.c.
[FIX]
Fix the output by:
- Move the btrfs_dev_name() helper to volumes.h
- Use btrfs_dev_name() to replace open-coded rcu_str_deref() calls
Only zoned code is not touched, as I'm not familiar with degraded
zoned code.
- Constify return value and parameter
Now the output looks pretty sane:
BTRFS info (device dm-1): dev_replace from <missing disk> (devid 2) to /dev/mapper/test-scratch2 started
BTRFS error (device dm-1): failed to rebuild valid logical 38862848 for dev <missing disk>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During lseek (SEEK_HOLE/DATA), whenever we find a hole or prealloc extent,
we will look for delalloc in that range, and one of the things we do for
that is to find out ranges in the inode's io_tree marked with
EXTENT_DELALLOC, using calls to count_range_bits().
Typically there's a single, or few, searches in the io_tree for delalloc
per lseek call. However it's common for applications to keep calling
lseek with SEEK_HOLE and SEEK_DATA to find where extents and holes are in
a file, read the extents and skip holes in order to avoid unnecessary IO
and save disk space by preserving holes.
One popular user is the cp utility from coreutils. Starting with coreutils
9.0, cp uses SEEK_HOLE and SEEK_DATA to iterate over the extents of a
file. Before 9.0, it used fiemap to figure out where holes and extents are
in the source file. Another popular user is the tar utility when used with
the --sparse / -S option to detect and preserve holes.
Given that the pattern is to keep calling lseek with a start offset that
matches the returned offset from the previous lseek call, we can benefit
from caching the last extent state visited in count_range_bits() and use
it for the next count_range_bits() from the next lseek call. Example,
the following strace excerpt from running tar:
$ strace tar cJSvf foo.tar.xz qemu_disk_file.raw
(...)
lseek(5, 125019574272, SEEK_HOLE) = 125024989184
lseek(5, 125024989184, SEEK_DATA) = 125024993280
lseek(5, 125024993280, SEEK_HOLE) = 125025239040
lseek(5, 125025239040, SEEK_DATA) = 125025255424
lseek(5, 125025255424, SEEK_HOLE) = 125025353728
lseek(5, 125025353728, SEEK_DATA) = 125025357824
lseek(5, 125025357824, SEEK_HOLE) = 125026766848
lseek(5, 125026766848, SEEK_DATA) = 125026770944
lseek(5, 125026770944, SEEK_HOLE) = 125027053568
(...)
Shows that pattern, which is the same as with cp from coreutils 9.0+.
So start using a cached state for the delalloc searches in lseek, and
store it in struct file's private data so that it can be reused across
lseek calls.
This change is part of a patchset that is comprised of the following
patches:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
The following test was run before and after applying the whole patchset:
$ cat test-cp.sh
#!/bin/bash
DEV=/dev/sdh
MNT=/mnt/sdh
# coreutils 8.32, cp uses fiemap to detect holes and extents
#CP_PROG=/usr/bin/cp
# coreutils 9.1, cp uses SEEK_HOLE/DATA to detect holes and extents
CP_PROG=/home/fdmanana/git/hub/coreutils/src/cp
umount $DEV &> /dev/null
mkfs.btrfs -f $DEV
mount $DEV $MNT
FILE_SIZE=$((1024 * 1024 * 1024))
echo "Creating file with a size of $((FILE_SIZE / 1024 / 1024))M"
# Create a very sparse file, where each extent has a length of 4K and
# is preceded by a 4K hole and followed by another 4K hole.
start=$(date +%s%N)
echo -n > $MNT/foobar
for ((off = 0; off < $FILE_SIZE; off += 8192)); do
xfs_io -c "pwrite -S 0xab $off 4K" $MNT/foobar > /dev/null
echo -ne "\r$off / $FILE_SIZE ..."
done
end=$(date +%s%N)
echo -e "\nFile created ($(( (end - start) / 1000000 )) milliseconds)"
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds with data/metadata cached and delalloc"
# Flush all delalloc.
sync
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds with data/metadata cached and no delalloc"
# Unmount and mount again to test the case without any metadata
# loaded in memory.
umount $MNT
mount $DEV $MNT
start=$(date +%s%N)
$CP_PROG $MNT/foobar /dev/null
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "cp took $dur milliseconds without data/metadata cached and no delalloc"
umount $MNT
The results, running on a box with a non-debug kernel (Debian's default
kernel config), were the following:
128M file, before patchset:
cp took 16574 milliseconds with data/metadata cached and delalloc
cp took 122 milliseconds with data/metadata cached and no delalloc
cp took 20144 milliseconds without data/metadata cached and no delalloc
128M file, after patchset:
cp took 6277 milliseconds with data/metadata cached and delalloc
cp took 109 milliseconds with data/metadata cached and no delalloc
cp took 210 milliseconds without data/metadata cached and no delalloc
512M file, before patchset:
cp took 14369 milliseconds with data/metadata cached and delalloc
cp took 429 milliseconds with data/metadata cached and no delalloc
cp took 88034 milliseconds without data/metadata cached and no delalloc
512M file, after patchset:
cp took 12106 milliseconds with data/metadata cached and delalloc
cp took 427 milliseconds with data/metadata cached and no delalloc
cp took 824 milliseconds without data/metadata cached and no delalloc
1G file, before patchset:
cp took 10074 milliseconds with data/metadata cached and delalloc
cp took 886 milliseconds with data/metadata cached and no delalloc
cp took 181261 milliseconds without data/metadata cached and no delalloc
1G file, after patchset:
cp took 3320 milliseconds with data/metadata cached and delalloc
cp took 880 milliseconds with data/metadata cached and no delalloc
cp took 1801 milliseconds without data/metadata cached and no delalloc
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During fiemap, whenever we find a hole or prealloc extent, we will look
for delalloc in that range, and one of the things we do for that is to
find out ranges in the inode's io_tree marked with EXTENT_DELALLOC, using
calls to count_range_bits().
Since we process file extents from left to right, if we have a file with
several holes or prealloc extents, we benefit from keeping a cached extent
state record for calls to count_range_bits(). Most of the time the last
extent state record we visited in one call to count_range_bits() matches
the first extent state record we will use in the next call to
count_range_bits(), so there's a benefit here. So use an extent state
record to cache results from count_range_bits() calls during fiemap.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The comment for count_range_bits() mentions that the search is fast if we
are asking for a range with the EXTENT_DIRTY bit set. However that is no
longer true since we don't use that bit and the optimization for that was
removed in:
commit 71528e9e16 ("btrfs: get rid of extent_io_tree::dirty_bytes")
So remove that part of the comment mentioning the no longer existing
optimized case, and, while at it, add proper documentation describing the
purpose, arguments and return value of the function.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
An inode's io_tree can be quite large and there are cases where due to
delalloc it can have thousands of extent state records, which makes the
red black tree have a depth of 10 or more, making the operation of
count_range_bits() slow if we repeatedly call it for a range that starts
where, or after, the previous one we called it for. Such use cases are
when searching for delalloc in a file range that corresponds to a hole or
a prealloc extent, which is done during lseek SEEK_HOLE/DATA and fiemap.
So introduce a cached state parameter to count_range_bits() which we use
to store the last extent state record we visited, and then allow the
caller to pass it again on its next call to count_range_bits(). The next
patches in the series will make fiemap and lseek use the new parameter.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are no more users of btrfs_next_extent_map(), the previous patch
in the series ("btrfs: search for delalloc more efficiently during
lseek/fiemap") removed the last usage of the function, so delete it.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During lseek (SEEK_HOLE/DATA) and fiemap, when processing a file range
that corresponds to a hole or a prealloc extent, we have to check if
there's any delalloc in the range. We do it by searching for delalloc
ranges in the inode's io_tree (for unflushed delalloc) and in the inode's
extent map tree (for delalloc that is flushing).
We avoid searching the extent map tree if the number of outstanding
extents is 0, as in that case we can't have extent maps for our search
range in the tree that correspond to delalloc that is flushing. However
if we have any unflushed delalloc, due to buffered writes or mmap writes,
then the outstanding extents counter is not 0 and we'll search the extent
map tree. The tree may be large because it can have lots of extent maps
that were loaded by reads or created by previous writes, therefore taking
a significant time to search the tree, specially if have a file with a
lot of holes and/or prealloc extents.
We can improve on this by instead of searching the extent map tree,
searching the ordered extents tree of the inode, since when delalloc is
flushing we create an ordered extent along with the new extent map, while
holding the respective file range locked in the inode's io_tree. The
ordered extents tree is typically much smaller, since ordered extents have
a short life and get removed from the tree once they are completed, while
extent maps can stay for a very long time in the extent map tree, either
created by previous writes or loaded by read operations.
So use the ordered extents tree instead of the extent maps tree.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During lseek (SEEK_HOLE/DATA) and fiemap, when processing a file range
that corresponds to a hole or a prealloc extent, if we find that there is
no delalloc marked in the inode's io_tree but there is delalloc due to
an extent map in the io tree, then on the next iteration that calls
find_delalloc_subrange() we can skip searching the io tree again, since
on the first call we had no delalloc in the io tree for the whole range.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During fiemap and lseek (SEEK_HOLE/DATA), when looking for delalloc in a
range corresponding to a hole or a prealloc extent, if we found the whole
range marked as delalloc in the inode's io_tree, then we can terminate
immediately and avoid searching the extent map tree. If not, and if the
found delalloc starts at the same offset of our search start but ends
before our search range's end, then we can adjust the search range for
the search in the extent map tree. So implement those changes.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to set the EXTENT_UPDATE bit in an inode's io_tree to mark a
range as uptodate, we rely on the pages themselves being uptodate - page
reading is not triggered for already uptodate pages. Recently we removed
most use of the EXTENT_UPTODATE for buffered IO with commit 52b029f427
("btrfs: remove unnecessary EXTENT_UPTODATE state in buffered I/O path"),
but there were a few leftovers, namely when reading from holes and
successfully finishing read repair.
These leftovers are unnecessarily making an inode's tree larger and deeper,
slowing down searches on it. So remove all the leftovers.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BACKGROUND]
Although both btrfs metadata and data has their read time verification
done at endio time (btrfs_validate_metadata_buffer() and
btrfs_verify_data_csum()), metadata has extra verification, mostly
parentness check including first key/transid/owner_root/level, done at
read_tree_block() and btrfs_read_extent_buffer().
On the other hand, all the data verification is done at endio context.
[ENHANCEMENT]
This patch will make a new union in btrfs_bio, taking the space of the
old data checksums, thus it will not increase the memory usage.
With that extra btrfs_tree_parent_check inside btrfs_bio, we can just
pass the check parameter into read_extent_buffer_pages(), and before
submitting the bio, we can copy the check structure into btrfs_bio.
And finally at endio time, we can grab btrfs_bio::parent_check and pass
it to validate_extent_buffer(), to move the remaining checks into it.
This brings the following benefits:
- Much simpler btrfs_read_extent_buffer()
Now it only needs to iterate through all mirrors.
- Simpler read-time transid check
Previously we go verify_parent_transid() after reading out the extent
buffer.
Now the transid check is done inside the endio function, no other
code can modify the content.
Thus no need to use the extent lock anymore.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are several different tree block parentness check parameters used
across several helpers:
- level
Mandatory
- transid
Under most cases it's mandatory, but there are several backref cases
which skips this check.
- owner_root
- first_key
Utilized by most top-down tree search routine. Otherwise can be
skipped.
Those four members are not always mandatory checks, and some of them are
the same u64, which means if some arguments got swapped compiler will
not catch it.
Furthermore if we're going to further expand the parentness check, we
need to modify quite some helpers just to add one more parameter.
This patch will concentrate all these members into a structure called
btrfs_tree_parent_check, and pass that structure for the following
helpers:
- btrfs_read_extent_buffer()
- read_tree_block()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is a repeating code section in the parent function after calling
btrfs_alloc_device(), as below:
name = rcu_string_strdup(path, GFP_...);
if (!name) {
btrfs_free_device(device);
return ERR_PTR(-ENOMEM);
}
rcu_assign_pointer(device->name, name);
Except in add_missing_dev() for obvious reasons.
This patch consolidates that repeating code into the btrfs_alloc_device()
itself so that the parent function doesn't have to duplicate code.
This consolidation also helps to review issues regarding RCU lock
violation with device->name.
Parent function device_list_add() and add_missing_dev() use GFP_NOFS for
the allocation, whereas the rest of the parent functions use GFP_KERNEL,
so bring the NOFS allocation context using memalloc_nofs_save() in the
function device_list_add() and add_missing_dev() is already doing it.
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 input buffers passed down to compression must never be changed,
switch type to u8 as it's a raw byte buffer and use const.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since all the recovery paths have been migrated to the new error bitmap
based system, we can remove the old stripe number based system.
This cleanup involves one behavior change:
- Rebuild rbio can no longer be merged
Previously a rebuild rbio (caused by retry after data csum mismatch)
can be merged, if the error happens in the same stripe.
But with the new error bitmap based solution, it's much harder to
compare error bitmaps.
So here we just don't merge rebuild rbio at all.
This may introduce some performance impact at extreme corner cases,
but we're willing to take it.
Other than that, this patch will cleanup the following members:
- rbio::faila
- rbio::failb
They will be replaced by per-vertical stripe check, which is more
accurate.
- rbio::error
It will be replace by per-vertical stripe error bitmap check.
- Allow get_rbio_vertical_errors() to accept NULL pointers for
@faila and @failb
Some call sites only want to check if we have errors beyond the
tolerance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we have rbio::error_bitmap to indicate exactly where the errors
are (including read error and csum mismatch error), we can make recovery
path more accurate.
For example:
0 32K 64K
Data 1 |XXXXXXXX| |
Data 2 | |XXXXXXXXX|
Parity | | |
1) Get csum mismatch when reading data 1 [0, 32K)
2) Mark corresponding range error
The old code will mark the whole data 1 stripe as error.
While the new code will only mark data 1 [0, 32K) as error.
3) Recovery path
The old code will recover data 1 [0, 64K), all using Data 2 and
parity.
This means, Data 1 [32K, 64K) will be corrupted data, as data 2
[32K, 64K) is already corrupted.
While the new code will only recover data 1 [0, 32K), as only
that range has error so far.
This new behavior can avoid populating rbio cache with incorrect data.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs raid56 uses btrfs_raid_bio::faila and failb to indicate
which stripe(s) had IO errors.
But that has some problems:
- If one sector failed csum check, the whole stripe where the corruption
is will be marked error.
This can reduce the chance we do recover, like this:
0 4K 8K
Data 1 |XX| |
Data 2 | |XX|
Parity | | |
In above case, 0~4K in data 1 should be recovered using data 2 and
parity, while 4K~8K in data 2 should be recovered using data 1 and
parity.
Currently if we trigger read on 0~4K of data 1, we will also recover
4K~8K of data 1 using corrupted data 2 and parity, causing wrong
result in rbio cache.
- Harder to expand for future M-N scheme
As we're limited to just faila/b, two corruptions.
- Harder to expand to handle extra csum errors
This can be problematic if we start to do csum verification.
This patch will introduce an extra @error_bitmap, where one bit
represents error that happened for that sector.
The choice to introduce a new error bitmap other than reusing
sector_ptr, is to avoid extra search between rbio::stripe_sectors[] and
rbio::bio_sectors[].
Since we can submit bio using sectors from both sectors, doing proper
search on both array will more complex.
Although the new bitmap will take extra memory, later we can remove
things like @error and faila/b to save some memory.
Currently the new error bitmap and failab mechanism coexists, the error
bitmap is only updated at endio time and recover entrance.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
