The path parameter was used for our own locking, that got converted to
rwsem eventually. Last usage in ac5887c8e0 ("btrfs: locking: remove
all the blocking helpers").
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Make sure we got the right timer struct for the zstd workspace reclaim
work.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function btrfs_set_range_writeback() was originally a callback for
metadata and data, to mark a range with writeback flag.
Then it was converted into a common function call for both metadata and
data.
From the very beginning, the function had been only called on a full page,
later converted to handle range inside a page.
But it never needed to handle multiple pages, and since commit
8189197425 ("btrfs: refactor __extent_writepage_io() to do
sector-by-sector submission") the function was only called on a
sector-by-sector basis.
This makes the function unnecessary, and can be converted to a simple
btrfs_folio_set_writeback() call instead.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When trying to flush qgroups in order to release space we run delayed
iputs in order to release space from recently deleted files (their link
counted reached zero), and then we start delalloc and wait for any
existing ordered extents to complete.
However there's a time window here where we end up not doing the final
iput on a deleted file which could release necessary space:
1) An unlink operation starts;
2) During the unlink, or right before it completes, delalloc is flushed
and an ordered extent is created;
3) When the ordered extent is created, the inode's ref count is
incremented (with igrab() at alloc_ordered_extent());
4) When the unlink finishes it doesn't drop the last reference on the
inode and so it doesn't trigger inode eviction to delete all of
the inode's items in its root and drop all references on its data
extents;
5) Another task enters try_flush_qgroup() to try to release space,
it runs all delayed iputs, but there's no delayed iput yet for that
deleted file because the ordered extent hasn't completed yet;
6) Then at try_flush_qgroup() we wait for the ordered extent to complete
and that results in adding a delayed iput at btrfs_put_ordered_extent()
when called from btrfs_finish_one_ordered();
7) Adding the delayed iput results in waking the cleaner kthread if it's
not running already. However it may take some time for it to be
scheduled, or it may be running but busy running auto defrag, dropping
deleted snapshots or doing other work, so by the time we return from
try_flush_qgroup() the space for deleted file isn't released.
Improve on this by running delayed iputs only after flushing delalloc
and waiting for ordered extent completion.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Performing the initial extent sector read on a RAID stripe-tree backed
filesystem with pre-allocated extents will cause the RAID stripe-tree
lookup code to return ENODATA, as pre-allocated extents do not have any
on-disk bytes and thus no RAID stripe-tree entries.
But the current scrub read code marks these extents as errors, because
the lookup fails.
If btrfs_map_block() returns -ENODATA, it means that the call to
btrfs_get_raid_extent_offset() returned -ENODATA, because there is no
entry for the corresponding range in the RAID stripe-tree. But as this
range is in the extent tree it means we've hit a pre-allocated extent. In
this case, don't mark the sector in the stripe's error bitmaps as faulty
and carry on to the next.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In case a lookup in the RAID stripe-tree fails, return ENODATA instead of
ENOENT to better distinguish stripe-tree lookups from other code paths
where we return ENOENT.
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we BUG_ON() in btrfs_finish_one_ordered() if we are finishing
an ordered extent that is flagged as NOCOW, but it's checksum list is
not empty.
This is clearly a logic error which we can recover from by aborting the
transaction.
For developer builds which enable CONFIG_BTRFS_ASSERT, also ASSERT()
that the list is empty.
Suggested-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently inside prepare_pages(), we handle the leading and tailing page
differently, and skip the middle pages (if any). This is to avoid
reading pages which are fully covered by the dirty range.
Refactor the code by moving all checks (alignment check, range check,
force read check) into prepare_uptodate_page().
So that prepare_pages() only needs to iterate all the pages
unconditionally.
And since we're here, also update prepare_uptodate_page() to use
folio API other than the old page API.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Inside btrfs_buffered_write(), we have a local variable @dirty_pages,
recording the number of pages we dirtied in the current iteration.
However we do not really need that variable, since it can be calculated
from @pos and @copied.
In fact there is already a problem inside the short copy path, where we
use @dirty_pages to calculate the range we need to release.
But that usage assumes sectorsize == PAGE_SIZE, which is no longer true.
Instead of keeping @dirty_pages and cause incorrect usage, just
calculate the number of dirtied pages inside btrfs_dirty_pages().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_try_tree_write_lock() has been unused since commit
50b21d7a06 ("btrfs: submit a writeback bio per extent_buffer").
Remove it as we don't need it anymore.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_is_parity_mirror() has been unused since commit 4886ff7b50
("btrfs: introduce a new helper to submit write bio for repair").
Remove it as the code was refactored and we don't need the helper
anymore.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_free_squota_rsv() was added in commit
e85a0adacf ("btrfs: ensure releasing squota reserve on head refs")
but has remained unused since then.
Remove it as we don't seem to need it and was probably a leftover.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add first stash of very basic self tests for the RAID stripe-tree.
More test cases will follow exercising the tree.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This macro is no longer used after the "btrfs: Cleaned up folio->page
conversion" series patch [1] was applied, so remove it.
[1]: https://patchwork.kernel.org/project/linux-btrfs/cover/20240828182908.3735344-1-lizetao1@huawei.com/
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The variable stop_loop was originally introduced in commit 625f1c8dc6
("Btrfs: improve the loop of scrub_stripe"). It was initialized to 0 in
commit 3b080b2564 ("Btrfs: scrub raid56 stripes in the right way").
However, in a later commit 18d30ab961 ("btrfs: scrub: use
scrub_simple_mirror() to handle RAID56 data stripe scrub"), the code
that modified stop_loop was removed, making the variable redundant.
Currently, stop_loop is only initialized with 0 and is never used or
modified within the scrub_stripe() function. As a result, this patch
removes the stop_loop variable to clean up the code and eliminate
unnecessary redundancy.
This change has no impact on functionality, as stop_loop was never
utilized in any meaningful way in the final version of the code.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Riyan Dhiman <riyandhiman14@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The qgroup record was allocated with kzalloc(), so it's pointless to set
its old_roots member to NULL. Remove the assignment.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of dereferencing the delayed refs from the transaction multiple
times, store it early in the local variable and then always use the
variable.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's no need to hold the delayed refs spinlock when calling
btrfs_qgroup_trace_extent_nolock() from btrfs_qgroup_trace_extent(), since
it doesn't change anything in delayed refs and it only changes the xarray
used to track qgroup extent records, which is protected by the xarray's
lock.
Holding the lock is only adding unnecessary lock contention with other
tasks that actually need to take the lock to add/remove/change delayed
references. So remove the locking.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of extracting fs_info from the transaction multiples times, store
it in a local variable and use it.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we track qgroup extent records in a xarray we don't need to have
a "bytenr" field in struct btrfs_qgroup_extent_record, since we can get
it from the index of the record in the xarray.
So remove the field and grab the bytenr from either the index key or any
other place where it's available (delayed refs). This reduces the size of
struct btrfs_qgroup_extent_record from 40 bytes down to 32 bytes, meaning
that we now can store 128 instances of this structure instead of 102 per
4K page.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove the duplicated transaction joining, block reserve setting and raid
extent inserting in btrfs_finish_ordered_extent().
While at it, also abort the transaction in case inserting a RAID
stripe-tree entry fails.
Suggested-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[PROBLEM]
Currently btrfs accepts any file path for its device, resulting some
weird situation:
# ./mount_by_fd /dev/test/scratch1 /mnt/btrfs/
The program has the following source code:
#include <fcntl.h>
#include <stdio.h>
#include <sys/mount.h>
int main(int argc, char *argv[]) {
int fd = open(argv[1], O_RDWR);
char path[256];
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
return mount(path, argv[2], "btrfs", 0, NULL);
}
Then we can have the following weird device path:
BTRFS: device fsid 2378be81-fe12-46d2-a9e8-68cf08dd98d5 devid 1 transid 7 /proc/self/fd/3 (253:2) scanned by mount_by_fd (18440)
Normally it's not a big deal, and later udev can trigger a device path
rename. But if udev didn't trigger, the device path "/proc/self/fd/3"
will show up in mtab.
[CAUSE]
For filename "/proc/self/fd/3", it means the opened file descriptor 3.
In above case, it's exactly the device we want to open, aka points to
"/dev/test/scratch1" which is another symlink pointing to "/dev/dm-2".
Inside kernel we solve the mount source using LOOKUP_FOLLOW, which
follows the symbolic link and grab the proper block device.
But inside btrfs we also save the filename into btrfs_device::name, and
utilize that member to report our mount source, which leads to the above
situation.
[FIX]
Instead of unconditionally trust the path, check if the original file
(not following the symbolic link) is inside "/dev/", if not, then
manually lookup the path to its final destination, and use that as our
device path.
This allows us to still use symbolic links, like
"/dev/mapper/test-scratch" from LVM2, which is required for fstests runs
with LVM2 setup.
And for really weird names, like the above case, we solve it to
"/dev/dm-2" instead.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1230641
Reported-by: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[PROBLEM]
It is very common for udev to trigger device scan, and every time a
mounted btrfs device got re-scan from different soft links, we will get
some of unnecessary device path updates, this is especially common
for LVM based storage:
# lvs
scratch1 test -wi-ao---- 10.00g
scratch2 test -wi-a----- 10.00g
scratch3 test -wi-a----- 10.00g
scratch4 test -wi-a----- 10.00g
scratch5 test -wi-a----- 10.00g
test test -wi-a----- 10.00g
# mkfs.btrfs -f /dev/test/scratch1
# mount /dev/test/scratch1 /mnt/btrfs
# dmesg -c
[ 205.705234] BTRFS: device fsid 7be2602f-9e35-4ecf-a6ff-9e91d2c182c9 devid 1 transid 6 /dev/mapper/test-scratch1 (253:4) scanned by mount (1154)
[ 205.710864] BTRFS info (device dm-4): first mount of filesystem 7be2602f-9e35-4ecf-a6ff-9e91d2c182c9
[ 205.711923] BTRFS info (device dm-4): using crc32c (crc32c-intel) checksum algorithm
[ 205.713856] BTRFS info (device dm-4): using free-space-tree
[ 205.722324] BTRFS info (device dm-4): checking UUID tree
So far so good, but even if we just touched any soft link of
"dm-4", we will get quite some unnecessary device path updates.
# touch /dev/mapper/test-scratch1
# dmesg -c
[ 469.295796] BTRFS info: devid 1 device path /dev/mapper/test-scratch1 changed to /dev/dm-4 scanned by (udev-worker) (1221)
[ 469.300494] BTRFS info: devid 1 device path /dev/dm-4 changed to /dev/mapper/test-scratch1 scanned by (udev-worker) (1221)
Such device path rename is unnecessary and can lead to random path
change due to the udev race.
[CAUSE]
Inside device_list_add(), we are using a very primitive way checking if
the device has changed, strcmp().
Which can never handle links well, no matter if it's hard or soft links.
So every different link of the same device will be treated as a different
device, causing the unnecessary device path update.
[FIX]
Introduce a helper, is_same_device(), and use path_equal() to properly
detect the same block device.
So that the different soft links won't trigger the rename race.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1230641
Reported-by: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Previously for btrfs with sector size smaller than page size (subpage),
we only allow compression if the range is fully page aligned.
This is to work around the asynchronous submission of compressed range,
which delayed the page unlock and writeback into a workqueue,
furthermore asynchronous submission can lock multiple sector range
across page boundary.
Such asynchronous submission makes it very hard to co-operate with other
regular writes.
With the recent changes to the subpage folio unlock path, now
asynchronous submission of compressed pages can co-operate with regular
submission, so enable sector perfect compression if it's an experimental
build.
The ETA for moving this feature out of experimental is 6.15, and I hope
all remaining corner cases can be exposed before that.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we only mark sectors as locked if there is a *NEW* delalloc
range for it.
But NEW delalloc range is not the same as dirty sectors we want to
submit, e.g:
0 32K 64K 96K 128K
| |////////||///////| |////|
120K
For above 64K page size case, writepage_delalloc() for page 0 will find
and lock the delalloc range [32K, 96K), which is beyond the page
boundary.
Then when writepage_delalloc() is called for the page 64K, since [64K,
96K) is already locked, only [120K, 128K) will be locked.
This means, although range [64K, 96K) is dirty and will be submitted
later by extent_writepage_io(), it will not be marked as locked.
This is fine for now, as we call btrfs_folio_end_writer_lock_bitmap() to
free every non-compressed sector, and compression is only allowed for
full page range.
But this is not safe for future sector perfect compression support, as
this can lead to double folio unlock:
Thread A | Thread B
---------------------------------------+--------------------------------
| submit_one_async_extent()
| |- extent_clear_unlock_delalloc()
extent_writepage() | |- btrfs_folio_end_writer_lock()
|- btrfs_folio_end_writer_lock_bitmap()| |- btrfs_subpage_end_and_test_writer()
| | | |- atomic_sub_and_test()
| | | /* Now the atomic value is 0 */
|- if (atomic_read() == 0) | |
|- folio_unlock() | |- folio_unlock()
The root cause is the above range [64K, 96K) is dirtied and should also
be locked but it isn't.
So to make everything more consistent and prepare for the incoming
sector perfect compression, mark all dirty sectors as locked.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently for subpage (sector size < page size) cases, we reuse subpage
locked bitmap to find out all delalloc ranges we have locked, and run
all those found ranges.
However such reuse is not perfect, e.g.:
0 32K 64K 96K 128K
| |////////||///////| |////|
120K
For above range, writepage_delalloc() for page 0 will handle the range
[32K, 96k), note delalloc range can be beyond the page boundary.
But writepage_delalloc() for page 64K will only handle range [120K,
128K), as the previous run on page 0 has already handled range [64K,
96K).
Meanwhile for the writeback we should expect range [64K, 96K) to also be
locked, this leads to the mismatch from locked bitmap and delalloc
range.
This is not causing problems yet, but it's still an inconsistent
behavior.
So instead of relying on the subpage locked bitmap, move the delalloc
range search using local @delalloc_bitmap, so that we can remove the
existing btrfs_folio_find_writer_locked().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function extent_writepage_io() will submit the dirty sectors inside
the page for the write.
But recently to co-operate with the incoming subpage compression
enhancement, a new bitmap is introduced to
btrfs_bio_ctrl::submit_bitmap, to only avoid a subset of the dirty
range.
This is because we can have the following cases with 64K page size:
0 16K 32K 48K 64K
| |/////////| |/|
52K
For range [16K, 32K), we queue the dirty range for compression, which is
ran in a delayed workqueue.
Then for range [48K, 52K), we go through the regular submission path.
In that case, our btrfs_bio_ctrl::submit_bitmap will exclude the range
[16K, 32K).
The dirty flags for the range [16K, 32K) is only cleared when the
compression is done, by the extent_clear_unlock_delalloc() call inside
submit_one_async_extent().
This patch fix the false alert by removing the
btrfs_folio_assert_not_dirty() check, since it's no longer correct for
subpage compression cases.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For btrfs with sector size < page size (e.g. 4K sector size, 64K page
size), and enable the sector perfect compression support, then the
following dirty range can lead to problems:
0 32K 64K 96K 128K
| |///////||//////| |/|
124K
In above case, if we start writeback for that inode, the last dirty
range [124K, 128K) will not be submitted and cause reserved space
leakage:
- Start writeback for page 0
We find the range [32K, 96K) is suitable for compression, and queue it
into a workqueue to do the delayed compression and submission.
- Compression happens for range [32K, 96K)
Function extent_range_clear_dirty_for_io() is called, however it is
only doing full page handling, not considering any the extra bitmaps
for subpage cases.
That function will clear page dirty for both page 0 and page 64K.
- Writeback for the inode is done
Because page 64K has its dirty flag cleared, it will not be considered
as a writeback target.
This means the range [124K, 128K) will not be submitted, and reserved
space for it will be leaked.
Fix this problem by using the subpage helper to clear the dirty flag.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[PROBLEM]
If sector perfect compression is enabled for sector size < page size
case, the following case can lead dirty ranges not being written back:
0 32K 64K 96K 128K
| |///////||//////| |/|
124K
In above example, the page size is 64K, and we need to write back above
two pages.
- Submit for page 0 (main thread)
We found delalloc range [32K, 96K), which can be compressed.
So we queue an async range for [32K, 96K).
This means, the page unlock/clearing dirty/setting writeback will
all happen in a workqueue context.
- The compression is done, and compressed range is submitted (workqueue)
Since the compression is done in asynchronously, the compression can
be done before the main thread to submit for page 64K.
Now the whole range [32K, 96K), involving two pages, will be marked
writeback.
- Submit for page 64K (main thread)
extent_write_cache_pages() got its wbc->sync_mode is WB_SYNC_NONE,
so it skips the writeback wait.
And unlock the page and exit. This means the dirty range [124K, 128K)
will never be submitted, until next writeback happens for page 64K.
This will never happen for previous kernels because:
- For sector size == page size case
Since one page is one sector, if a page is marked writeback it will
not have dirty flags.
So this corner case will never hit.
- For sector size < page size case
We never do subpage compression, a range can only be submitted for
compression if the range is fully page aligned.
This change makes the subpage behavior mostly the same as non-subpage
cases.
[ENHANCEMENT]
Instead of relying WB_SYNC_NONE check only, if it's a subpage case, then
always wait for writeback flags.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are already two bugs (one in zlib, one in zstd) that involved
compression path is not handling sector size < page size cases well.
So it makes more sense to make sure that btrfs_compress_folios() returns
Since we already have two bugs (one in zlib, one in zstd) in the
compression path resulting the @total_in be to larger than the
to-be-compressed range length, there is enough reason to add an ASSERT()
to make sure the total read-in length doesn't exceed the input length.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Inside zstd_compress_folios(), after exhausted one input page, we need
to switch to the next page as input.
However when counting the total input bytes (@tot_in), we always increase
it by PAGE_SIZE.
For the following case, it can cause incorrect value:
0 32K 64K 96K
| |///////////||///////////|
After compressing range [32K, 64K), we switch to the next page, and
increasing @tot_in by 64K, while we only read 32K.
This will cause the @total_in to return a value larger than the input
length.
Fix it by only increase @tot_in by the input size.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Inside zlib_compress_folios(), each time we switch the input page cache,
the @start is increased by PAGE_SIZE.
But for the incoming compression support for sector size < page size
(previously we support compression only when the range is fully page
aligned), this is not going to handle the following case:
0 32K 64K 96K
| |///////////||///////////|
@start has the initial value 32K, indicating the start filepos of the
to-be-compressed range.
And when grabbing the first page as input, we always call "start +=
PAGE_SIZE;".
But since @start is starting at 32K, it will be increased by 64K,
resulting it to be 96K for the next range, causing incorrect input range
and corruption for the future subpage compression.
Fix it by only increase @start by the input size.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently CONFIG_BTRFS_EXPERIMENTAL is not only for the extra debugging
output, but also for experimental features.
This is not ideal to distinguish planned but not yet stable features
from those purely designed for debugging.
This patch splits the following features into CONFIG_BTRFS_EXPERIMENTAL:
- Extent map shrinker
This seems to be the first one to exit experimental.
- Extent tree v2
This seems to be the last one to graduate from experimental.
- Raid stripe tree
- Csum offload mode
- Send protocol v3
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>
According to the description, CONFIG_BTRFS_DEBUG is only for extra
debug info, meanwhile sanity checks should be managed by
CONFIG_BTRFS_ASSERT.
There is no need to check both to enable assert_rbio().
Just remove the check for CONFIG_BTRFS_DEBUG.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-6.12-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more one-liners that fix some user visible problems:
- use correct range when clearing qgroup reservations after COW
- properly reset freed delayed ref list head
- fix ro/rw subvolume mounts to be backward compatible with old and
new mount API"
* tag 'for-6.12-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix the length of reserved qgroup to free
btrfs: reinitialize delayed ref list after deleting it from the list
btrfs: fix per-subvolume RO/RW flags with new mount API
Code to support CXL Dynamic Capacity devices will have extent ranges
which need to be compared for intersection not a subset as is being
checked in range_contains().
range_overlaps() is defined in btrfs with a different meaning from what
is required in the standard range code. Dan Williams pointed this out
in [1]. Adjust the btrfs call according to his suggestion there.
Then add a generic range_overlaps().
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Link: https://lore.kernel.org/all/65949f79ef908_8dc68294f2@dwillia2-xfh.jf.intel.com.notmuch/ [1]
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://patch.msgid.link/20241107-dcd-type2-upstream-v7-1-56a84e66bc36@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
The dealloc flag may be cleared and the extent won't reach the disk in
cow_file_range when errors path. The reserved qgroup space is freed in
commit 30479f31d4 ("btrfs: fix qgroup reserve leaks in
cow_file_range"). However, the length of untouched region to free needs
to be adjusted with the correct remaining region size.
Fixes: 30479f31d4 ("btrfs: fix qgroup reserve leaks in cow_file_range")
CC: stable@vger.kernel.org # 6.11+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Haisu Wang <haisuwang@tencent.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At insert_delayed_ref() if we need to update the action of an existing
ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's
ref_add_list using list_del(), which leaves the ref's add_list member
not reinitialized, as list_del() sets the next and prev members of the
list to LIST_POISON1 and LIST_POISON2, respectively.
If later we end up calling drop_delayed_ref() against the ref, which can
happen during merging or when destroying delayed refs due to a transaction
abort, we can trigger a crash since at drop_delayed_ref() we call
list_empty() against the ref's add_list, which returns false since
the list was not reinitialized after the list_del() and as a consequence
we call list_del() again at drop_delayed_ref(). This results in an
invalid list access since the next and prev members are set to poison
pointers, resulting in a splat if CONFIG_LIST_HARDENED and
CONFIG_DEBUG_LIST are set or invalid poison pointer dereferences
otherwise.
So fix this by deleting from the list with list_del_init() instead.
Fixes: 1d57ee9416 ("btrfs: improve delayed refs iterations")
CC: stable@vger.kernel.org # 4.19+
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>
[BUG]
With util-linux 2.40.2, the 'mount' utility is already utilizing the new
mount API. e.g:
# strace mount -o subvol=subv1,ro /dev/test/scratch1 /mnt/test/
...
fsconfig(3, FSCONFIG_SET_STRING, "source", "/dev/mapper/test-scratch1", 0) = 0
fsconfig(3, FSCONFIG_SET_STRING, "subvol", "subv1", 0) = 0
fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0
fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = 0
fsmount(3, FSMOUNT_CLOEXEC, 0) = 4
mount_setattr(4, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY, attr_clr=0, propagation=0 /* MS_??? */, userns_fd=0}, 32) = 0
move_mount(4, "", AT_FDCWD, "/mnt/test", MOVE_MOUNT_F_EMPTY_PATH) = 0
But this leads to a new problem, that per-subvolume RO/RW mount no
longer works, if the initial mount is RO:
# mount -o subvol=subv1,ro /dev/test/scratch1 /mnt/test
# mount -o rw,subvol=subv2 /dev/test/scratch1 /mnt/scratch
# mount | grep mnt
/dev/mapper/test-scratch1 on /mnt/test type btrfs (ro,relatime,discard=async,space_cache=v2,subvolid=256,subvol=/subv1)
/dev/mapper/test-scratch1 on /mnt/scratch type btrfs (ro,relatime,discard=async,space_cache=v2,subvolid=257,subvol=/subv2)
# touch /mnt/scratch/foobar
touch: cannot touch '/mnt/scratch/foobar': Read-only file system
This is a common use cases on distros.
[CAUSE]
We have a workaround for remount to handle the RO->RW change, but if the
mount is using the new mount API, we do not do that, and rely on the
mount tool NOT to set the ro flag.
But that's not how the mount tool is doing for the new API:
fsconfig(3, FSCONFIG_SET_STRING, "source", "/dev/mapper/test-scratch1", 0) = 0
fsconfig(3, FSCONFIG_SET_STRING, "subvol", "subv1", 0) = 0
fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0 <<<< Setting RO flag for super block
fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = 0
fsmount(3, FSMOUNT_CLOEXEC, 0) = 4
mount_setattr(4, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY, attr_clr=0, propagation=0 /* MS_??? */, userns_fd=0}, 32) = 0
move_mount(4, "", AT_FDCWD, "/mnt/test", MOVE_MOUNT_F_EMPTY_PATH) = 0
This means we will set the super block RO at the first mount.
Later RW mount will not try to reconfigure the fs to RW because the
mount tool is already using the new API.
This totally breaks the per-subvolume RO/RW mount behavior.
[FIX]
Do not skip the reconfiguration even if using the new API. The old
comments are just expecting any mount tool to properly skip the RO flag
set even if we specify "ro", which is not the reality.
Update the comments regarding the backward compatibility on the kernel
level so it works with old and new mount utilities.
CC: stable@vger.kernel.org # 6.8+
Fixes: f044b31867 ("btrfs: handle the ro->rw transition for mounting different subvolumes")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'for-6.12-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more stability fixes. There's one patch adding export of MIPS
cmpxchg helper, used in the error propagation fix.
- fix error propagation from split bios to the original btrfs bio
- fix merging of adjacent extents (normal operation, defragmentation)
- fix potential use after free after freeing btrfs device structures"
* tag 'for-6.12-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix defrag not merging contiguous extents due to merged extent maps
btrfs: fix extent map merging not happening for adjacent extents
btrfs: fix use-after-free of block device file in __btrfs_free_extra_devids()
btrfs: fix error propagation of split bios
MIPS: export __cmpxchg_small()
When running defrag (manual defrag) against a file that has extents that
are contiguous and we already have the respective extent maps loaded and
merged, we end up not defragging the range covered by those contiguous
extents. This happens when we have an extent map that was the result of
merging multiple extent maps for contiguous extents and the length of the
merged extent map is greater than or equals to the defrag threshold
length.
The script below reproduces this scenario:
$ cat test.sh
#!/bin/bash
DEV=/dev/sdi
MNT=/mnt/sdi
mkfs.btrfs -f $DEV
mount $DEV $MNT
# Create a 256K file with 4 extents of 64K each.
xfs_io -f -c "falloc 0 64K" \
-c "pwrite 0 64K" \
-c "falloc 64K 64K" \
-c "pwrite 64K 64K" \
-c "falloc 128K 64K" \
-c "pwrite 128K 64K" \
-c "falloc 192K 64K" \
-c "pwrite 192K 64K" \
$MNT/foo
umount $MNT
echo -n "Initial number of file extent items: "
btrfs inspect-internal dump-tree -t 5 $DEV | grep EXTENT_DATA | wc -l
mount $DEV $MNT
# Read the whole file in order to load and merge extent maps.
cat $MNT/foo > /dev/null
btrfs filesystem defragment -t 128K $MNT/foo
umount $MNT
echo -n "Number of file extent items after defrag with 128K threshold: "
btrfs inspect-internal dump-tree -t 5 $DEV | grep EXTENT_DATA | wc -l
mount $DEV $MNT
# Read the whole file in order to load and merge extent maps.
cat $MNT/foo > /dev/null
btrfs filesystem defragment -t 256K $MNT/foo
umount $MNT
echo -n "Number of file extent items after defrag with 256K threshold: "
btrfs inspect-internal dump-tree -t 5 $DEV | grep EXTENT_DATA | wc -l
Running it:
$ ./test.sh
Initial number of file extent items: 4
Number of file extent items after defrag with 128K threshold: 4
Number of file extent items after defrag with 256K threshold: 4
The 4 extents don't get merged because we have an extent map with a size
of 256K that is the result of merging the individual extent maps for each
of the four 64K extents and at defrag_lookup_extent() we have a value of
zero for the generation threshold ('newer_than' argument) since this is a
manual defrag. As a consequence we don't call defrag_get_extent() to get
an extent map representing a single file extent item in the inode's
subvolume tree, so we end up using the merged extent map at
defrag_collect_targets() and decide not to defrag.
Fix this by updating defrag_lookup_extent() to always discard extent maps
that were merged and call defrag_get_extent() regardless of the minimum
generation threshold ('newer_than' argument).
A test case for fstests will be sent along soon.
CC: stable@vger.kernel.org # 6.1+
Fixes: 199257a78b ("btrfs: defrag: don't use merged extent map for their generation check")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we have 3 or more adjacent extents in a file, that is, consecutive file
extent items pointing to adjacent extents, within a contiguous file range
and compatible flags, we end up not merging all the extents into a single
extent map.
For example:
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt/sdc
$ xfs_io -f -d -c "pwrite -b 64K 0 64K" \
-c "pwrite -b 64K 64K 64K" \
-c "pwrite -b 64K 128K 64K" \
-c "pwrite -b 64K 192K 64K" \
/mnt/sdc/foo
After all the ordered extents complete we unpin the extent maps and try
to merge them, but instead of getting a single extent map we get two
because:
1) When the first ordered extent completes (file range [0, 64K)) we
unpin its extent map and attempt to merge it with the extent map for
the range [64K, 128K), but we can't because that extent map is still
pinned;
2) When the second ordered extent completes (file range [64K, 128K)), we
unpin its extent map and merge it with the previous extent map, for
file range [0, 64K), but we can't merge with the next extent map, for
the file range [128K, 192K), because this one is still pinned.
The merged extent map for the file range [0, 128K) gets the flag
EXTENT_MAP_MERGED set;
3) When the third ordered extent completes (file range [128K, 192K)), we
unpin its extent map and attempt to merge it with the previous extent
map, for file range [0, 128K), but we can't because that extent map
has the flag EXTENT_MAP_MERGED set (mergeable_maps() returns false
due to different flags) while the extent map for the range [128K, 192K)
doesn't have that flag set.
We also can't merge it with the next extent map, for file range
[192K, 256K), because that one is still pinned.
At this moment we have 3 extent maps:
One for file range [0, 128K), with the flag EXTENT_MAP_MERGED set.
One for file range [128K, 192K).
One for file range [192K, 256K) which is still pinned;
4) When the fourth and final extent completes (file range [192K, 256K)),
we unpin its extent map and attempt to merge it with the previous
extent map, for file range [128K, 192K), which succeeds since none
of these extent maps have the EXTENT_MAP_MERGED flag set.
So we end up with 2 extent maps:
One for file range [0, 128K), with the flag EXTENT_MAP_MERGED set.
One for file range [128K, 256K), with the flag EXTENT_MAP_MERGED set.
Since after merging extent maps we don't attempt to merge again, that
is, merge the resulting extent map with the one that is now preceding
it (and the one following it), we end up with those two extent maps,
when we could have had a single extent map to represent the whole file.
Fix this by making mergeable_maps() ignore the EXTENT_MAP_MERGED flag.
While this doesn't present any functional issue, it prevents the merging
of extent maps which allows to save memory, and can make defrag not
merging extents too (that will be addressed in the next patch).
Fixes: 199257a78b ("btrfs: defrag: don't use merged extent map for their generation check")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Mounting btrfs from two images (which have the same one fsid and two
different dev_uuids) in certain executing order may trigger an UAF for
variable 'device->bdev_file' in __btrfs_free_extra_devids(). And
following are the details:
1. Attach image_1 to loop0, attach image_2 to loop1, and scan btrfs
devices by ioctl(BTRFS_IOC_SCAN_DEV):
/ btrfs_device_1 → loop0
fs_device
\ btrfs_device_2 → loop1
2. mount /dev/loop0 /mnt
btrfs_open_devices
btrfs_device_1->bdev_file = btrfs_get_bdev_and_sb(loop0)
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
fail: btrfs_close_devices // -ENOMEM
btrfs_close_bdev(btrfs_device_1)
fput(btrfs_device_1->bdev_file)
// btrfs_device_1->bdev_file is freed
btrfs_close_bdev(btrfs_device_2)
fput(btrfs_device_2->bdev_file)
3. mount /dev/loop1 /mnt
btrfs_open_devices
btrfs_get_bdev_and_sb(&bdev_file)
// EIO, btrfs_device_1->bdev_file is not assigned,
// which points to a freed memory area
btrfs_device_2->bdev_file = btrfs_get_bdev_and_sb(loop1)
btrfs_fill_super
open_ctree
btrfs_free_extra_devids
if (btrfs_device_1->bdev_file)
fput(btrfs_device_1->bdev_file) // UAF !
Fix it by setting 'device->bdev_file' as 'NULL' after closing the
btrfs_device in btrfs_close_one_device().
Fixes: 1423881941 ("btrfs: do not background blkdev_put()")
CC: stable@vger.kernel.org # 4.19+
Link: https://bugzilla.kernel.org/show_bug.cgi?id=219408
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add a helper to get the queue_limits from the bdev without having to
poke into the request_queue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20241029141937.249920-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Most of the callers of wbc_account_cgroup_owner() are converting a folio
to page before calling the function. wbc_account_cgroup_owner() is
converting the page back to a folio to call mem_cgroup_css_from_folio().
Convert wbc_account_cgroup_owner() to take a folio instead of a page,
and convert all callers to pass a folio directly except f2fs.
Convert the page to folio for all the callers from f2fs as they were the
only callers calling wbc_account_cgroup_owner() with a page. As f2fs is
already in the process of converting to folios, these call sites might
also soon be calling wbc_account_cgroup_owner() with a folio directly in
the future.
No functional changes. Only compile tested.
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20240926140121.203821-1-kernel@pankajraghav.com
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'for-6.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- mount option fixes:
- fix handling of compression mount options on remount
- reject rw remount in case there are options that don't work
in read-write mode (like rescue options)
- fix zone accounting of unusable space
- fix in-memory corruption when merging extent maps
- fix delalloc range locking for sector < page
- use more convenient default value of drop subtree threshold, clean
more subvolumes without the fallback to marking quotas inconsistent
- fix smatch warning about incorrect value passed to ERR_PTR
* tag 'for-6.12-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix passing 0 to ERR_PTR in btrfs_search_dir_index_item()
btrfs: reject ro->rw reconfiguration if there are hard ro requirements
btrfs: fix read corruption due to race with extent map merging
btrfs: fix the delalloc range locking if sector size < page size
btrfs: qgroup: set a more sane default value for subtree drop threshold
btrfs: clear force-compress on remount when compress mount option is given
btrfs: zoned: fix zone unusable accounting for freed reserved extent
The purpose of btrfs_bbio_propagate_error() shall be propagating an error
of split bio to its original btrfs_bio, and tell the error to the upper
layer. However, it's not working well on some cases.
* Case 1. Immediate (or quick) end_bio with an error
When btrfs sends btrfs_bio to mirrored devices, btrfs calls
btrfs_bio_end_io() when all the mirroring bios are completed. If that
btrfs_bio was split, it is from btrfs_clone_bioset and its end_io function
is btrfs_orig_write_end_io. For this case, btrfs_bbio_propagate_error()
accesses the orig_bbio's bio context to increase the error count.
That works well in most cases. However, if the end_io is called enough
fast, orig_bbio's (remaining part after split) bio context may not be
properly set at that time. Since the bio context is set when the orig_bbio
(the last btrfs_bio) is sent to devices, that might be too late for earlier
split btrfs_bio's completion. That will result in NULL pointer
dereference.
That bug is easily reproducible by running btrfs/146 on zoned devices [1]
and it shows the following trace.
[1] You need raid-stripe-tree feature as it create "-d raid0 -m raid1" FS.
BUG: kernel NULL pointer dereference, address: 0000000000000020
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 UID: 0 PID: 13 Comm: kworker/u32:1 Not tainted 6.11.0-rc7-BTRFS-ZNS+ #474
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: writeback wb_workfn (flush-btrfs-5)
RIP: 0010:btrfs_bio_end_io+0xae/0xc0 [btrfs]
BTRFS error (device dm-0): bdev /dev/mapper/error-test errs: wr 2, rd 0, flush 0, corrupt 0, gen 0
RSP: 0018:ffffc9000006f248 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888005a7f080 RCX: ffffc9000006f1dc
RDX: 0000000000000000 RSI: 000000000000000a RDI: ffff888005a7f080
RBP: ffff888011dfc540 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff82e508e0 R11: 0000000000000005 R12: ffff88800ddfbe58
R13: ffff888005a7f080 R14: ffff888005a7f158 R15: ffff888005a7f158
FS: 0000000000000000(0000) GS:ffff88803ea80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000020 CR3: 0000000002e22006 CR4: 0000000000370ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
? __die_body.cold+0x19/0x26
? page_fault_oops+0x13e/0x2b0
? _printk+0x58/0x73
? do_user_addr_fault+0x5f/0x750
? exc_page_fault+0x76/0x240
? asm_exc_page_fault+0x22/0x30
? btrfs_bio_end_io+0xae/0xc0 [btrfs]
? btrfs_log_dev_io_error+0x7f/0x90 [btrfs]
btrfs_orig_write_end_io+0x51/0x90 [btrfs]
dm_submit_bio+0x5c2/0xa50 [dm_mod]
? find_held_lock+0x2b/0x80
? blk_try_enter_queue+0x90/0x1e0
__submit_bio+0xe0/0x130
? ktime_get+0x10a/0x160
? lockdep_hardirqs_on+0x74/0x100
submit_bio_noacct_nocheck+0x199/0x410
btrfs_submit_bio+0x7d/0x150 [btrfs]
btrfs_submit_chunk+0x1a1/0x6d0 [btrfs]
? lockdep_hardirqs_on+0x74/0x100
? __folio_start_writeback+0x10/0x2c0
btrfs_submit_bbio+0x1c/0x40 [btrfs]
submit_one_bio+0x44/0x60 [btrfs]
submit_extent_folio+0x13f/0x330 [btrfs]
? btrfs_set_range_writeback+0xa3/0xd0 [btrfs]
extent_writepage_io+0x18b/0x360 [btrfs]
extent_write_locked_range+0x17c/0x340 [btrfs]
? __pfx_end_bbio_data_write+0x10/0x10 [btrfs]
run_delalloc_cow+0x71/0xd0 [btrfs]
btrfs_run_delalloc_range+0x176/0x500 [btrfs]
? find_lock_delalloc_range+0x119/0x260 [btrfs]
writepage_delalloc+0x2ab/0x480 [btrfs]
extent_write_cache_pages+0x236/0x7d0 [btrfs]
btrfs_writepages+0x72/0x130 [btrfs]
do_writepages+0xd4/0x240
? find_held_lock+0x2b/0x80
? wbc_attach_and_unlock_inode+0x12c/0x290
? wbc_attach_and_unlock_inode+0x12c/0x290
__writeback_single_inode+0x5c/0x4c0
? do_raw_spin_unlock+0x49/0xb0
writeback_sb_inodes+0x22c/0x560
__writeback_inodes_wb+0x4c/0xe0
wb_writeback+0x1d6/0x3f0
wb_workfn+0x334/0x520
process_one_work+0x1ee/0x570
? lock_is_held_type+0xc6/0x130
worker_thread+0x1d1/0x3b0
? __pfx_worker_thread+0x10/0x10
kthread+0xee/0x120
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Modules linked in: dm_mod btrfs blake2b_generic xor raid6_pq rapl
CR2: 0000000000000020
* Case 2. Earlier completion of orig_bbio for mirrored btrfs_bios
btrfs_bbio_propagate_error() assumes the end_io function for orig_bbio is
called last among split bios. In that case, btrfs_orig_write_end_io() sets
the bio->bi_status to BLK_STS_IOERR by seeing the bioc->error [2].
Otherwise, the increased orig_bio's bioc->error is not checked by anyone
and return BLK_STS_OK to the upper layer.
[2] Actually, this is not true. Because we only increases orig_bioc->errors
by max_errors, the condition "atomic_read(&bioc->error) > bioc->max_errors"
is still not met if only one split btrfs_bio fails.
* Case 3. Later completion of orig_bbio for un-mirrored btrfs_bios
In contrast to the above case, btrfs_bbio_propagate_error() is not working
well if un-mirrored orig_bbio is completed last. It sets
orig_bbio->bio.bi_status to the btrfs_bio's error. But, that is easily
over-written by orig_bbio's completion status. If the status is BLK_STS_OK,
the upper layer would not know the failure.
* Solution
Considering the above cases, we can only save the error status in the
orig_bbio (remaining part after split) itself as it is always
available. Also, the saved error status should be propagated when all the
split btrfs_bios are finished (i.e, bbio->pending_ios == 0).
This commit introduces "status" to btrfs_bbio and saves the first error of
split bios to original btrfs_bio's "status" variable. When all the split
bios are finished, the saved status is loaded into original btrfs_bio's
status.
With this commit, btrfs/146 on zoned devices does not hit the NULL pointer
dereference anymore.
Fixes: 852eee62d3 ("btrfs: allow btrfs_submit_bio to split bios")
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
