kernel/linux.git/fs/btrfs/ordered-data.h, branch v6.6.145

btrfs: fix false IO failure after falling back to buffered write

2026-07-24T14:03:52+00:00

[ Upstream commit 66ff4d366e7eb4d31813d2acabf3af512ce03aa5 ] [BUG] The test case generic/362 will fail with "nodatasum" mount option (*): MOUNT_OPTIONS -- -o nodatasum /dev/mapper/test-scratch1 /mnt/scratch # generic/362 0s ... - output mismatch (see /home/adam/xfstests/results//generic/362.out.bad) # --- tests/generic/362.out 2024-08-24 15:31:37.200000000 +0930 # +++ /home/adam/xfstests/results//generic/362.out.bad 2026-05-27 10:21:17.574771567 +0930 # @@ -1,2 +1,3 @@ # QA output created by 362 # +First write failed: Input/output error # Silence is golden # ... *: If the test case has been executed before with default data checksum, the failure will not reproduce. Need the following fix to make it reliably reproducible: https://lore.kernel.org/linux-btrfs/20260528111659.87113-1-wqu@suse.com/ [CAUSE] Inside __iomap_dio_rw(), the -EFAULT/-ENOTBLK error is not directly returned. Thus we never got an error pointer from __iomap_dio_rw(). The call chain looks like this: btrfs_direct_write() |- btrfs_dio_write() |- __iomap_dio_rw() | |- iomap_iter() | | |- btrfs_dio_iomap_begin() | | Now an ordered extent is allocated for the 4K write. | | | |- iomi.status = iomap_dio_iter() | | Where iomap_dio_iter() returned -EFAULT. | | | |- ret = iomap_iter() | | |- btrfs_dio_iomap_end() | | | |- btrfs_finish_ordered_extent(uptodate = false) | | | | |- can_finish_ordered_extent() | | | | |- btrfs_mark_ordered_extent_error() | | | | |- mapping_set_error() | | | | Now the address space is marked error. | | | | return -ENOTBLK | | |- return -ENOTBLK | |- if (ret == -ENOTBLK) { ret = 0; } | Now the return value is reset to 0. | Thus no error pointer will be returned. | |- ret = iomap_dio_complete() | Since no byte is submitted, @ret is 0. | |- Fallback to buffered IO | And the buffered write finished without error | |- filemap_fdatawait_range() |- filemap_check_errors() The previous error is recorded, thus an error is returned However the buffered write is properly submitted and finished, the error is from the btrfs_finish_ordered_extent() call with @uptodate = false. [FIX] When a short dio write happened, any range that is submitted will have btrfs_extract_ordered_extent() to be called, thus the submitted range will always have an OE just covering the submitted range. The remaining OE range is never submitted, thus they should be treated as truncated, not an error. So that we can properly reclaim and not insert an unnecessary file extent item, without marking the mapping as error. Extract a helper, btrfs_mark_ordered_extent_truncated(), and utilize that helper to mark the direct IO ordered extent as truncated, so it won't cause failure for the later buffered fallback. [REASON FOR NO FIXES TAG] The bug itself is pretty old, at commit f85781fb505e ("btrfs: switch to iomap for direct IO") we're already passing @uptodate=false finishing the OE. But at that time OE with IOERR won't call mapping_set_error(), so it's not exposed. Later commit d61bec08b904 ("btrfs: mark ordered extent and inode with error if we fail to finish") finally exposed the bug, but that commit is doing a correct job, not the root cause. Anyway the bug is very old, dating back to 5.1x days, thus only CC to stable. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

btrfs: add support for inserting raid stripe extents

2026-03-25T10:05:30+00:00

[ Upstream commit 02c372e1f016e5113217597ab37b399c4e407477 ] Add support for inserting stripe extents into the raid stripe tree on completion of every write that needs an extra logical-to-physical translation when using RAID. Inserting the stripe extents happens after the data I/O has completed, this is done to a) support zone-append and b) rule out the possibility of a RAID-write-hole. Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba Stable-dep-of: 511dc8912ae3 ("btrfs: fix incorrect key offset in error message in check_dev_extent_item()") Signed-off-by: Sasha Levin

btrfs: add a btrfs_finish_ordered_extent helper

2023-06-19T11:59:37+00:00

Add a helper to complete an ordered_extent without first doing a lookup. The tracepoint cannot use the ordered_extent class as we also want to print the range. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: remove btrfs_add_ordered_extent

2023-06-19T11:59:36+00:00

All callers are gone now. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: defer splitting of ordered extents until I/O completion

2023-06-19T11:59:33+00:00

The btrfs zoned completion code currently needs an ordered_extent and extent_map per bio so that it can account for the non-predictable write location from Zone Append. To archive that it currently splits the ordered_extent and extent_map at I/O submission time, and then records the actual physical address in the ->physical field of the ordered_extent. This patch instead switches to record the "original" physical address that the btrfs allocator assigned in spare space in the btrfs_bio, and then rewrites the logical address in the btrfs_ordered_sum structure at I/O completion time. This allows the ordered extent completion handler to simply walk the list of ordered csums and split the ordered extent as needed. This removes an extra ordered extent and extent_map lookup and manipulation during the I/O submission path, and instead batches it in the I/O completion path where we need to touch these anyway. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: return the new ordered_extent from btrfs_split_ordered_extent

2023-06-19T11:59:33+00:00

Return the ordered_extent split from the passed in one. This will be needed to be able to store an ordered_extent in the btrfs_bio. Reviewed-by: Naohiro Aota Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: optimize the logical to physical mapping for zoned writes

2023-06-19T11:59:32+00:00

The current code to store the final logical to physical mapping for a zone append write in the extent tree is rather inefficient. It first has to split the ordered extent so that there is one ordered extent per bio, so that it can look up the ordered extent on I/O completion in btrfs_record_physical_zoned and store the physical LBA returned by the block driver in the ordered extent. btrfs_rewrite_logical_zoned then has to do a lookup in the chunk tree to see what physical address the logical address for this bio / ordered extent is mapped to, and then rewrite it in the extent tree. To optimize this process, we can store the physical address assigned in the chunk tree to the original logical address and a pointer to btrfs_ordered_sum structure the in the btrfs_bio structure, and then use this information to rewrite the logical address in the btrfs_ordered_sum structure directly at I/O completion time in btrfs_record_physical_zoned. btrfs_rewrite_logical_zoned then simply updates the logical address in the extent tree and the ordered_extent itself. The code in btrfs_rewrite_logical_zoned now runs for all data I/O completions in zoned file systems, which is fine as there is no remapping to do for non-append writes to conventional zones or for relocation, and the overhead for quickly breaking out of the loop is very low. Because zoned file systems now need the ordered_sums structure to record the actual write location returned by zone append, allocate dummy structures without the csum array for them when the I/O doesn't use checksums, and free them when completing the ordered_extent. Note that the btrfs_bio doesn't grow as the new field are places into a union that is so far not used for data writes and has plenty of space left in it. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename the bytenr field in struct btrfs_ordered_sum to logical

2023-06-19T11:59:32+00:00

btrfs_ordered_sum::bytendr stores a logical address. Make that clear by renaming it to ->logical. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: mark the len field in struct btrfs_ordered_sum as unsigned

2023-06-19T11:59:32+00:00

len can't ever be negative, so mark it as an u32 instead of int. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: sink parameter len to btrfs_split_ordered_extent

2023-04-17T16:01:21+00:00

btrfs_split_ordered_extent is only ever asked to split out the beginning of an ordered_extent (i.e. post == 0). Change it to only take a len to split out, and switch it to allocate the new extent for the beginning, as that helps with callers that want to keep a pointer to the ordered_extent that it is stealing from. Reviewed-by: Naohiro Aota Reviewed-by: Josef Bacik Tested-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba