kernel/linux.git/fs/btrfs/compression.c, branch v6.6.133

btrfs: zlib: fix and simplify the inline extent decompression

2024-08-29T15:33:32+00:00

[ Upstream commit 2c25716dcc25a0420c4ad49d6e6bf61e60a21434 ] [BUG] If we have a filesystem with 4k sectorsize, and an inlined compressed extent created like this: item 4 key (257 INODE_ITEM 0) itemoff 15863 itemsize 160 generation 8 transid 8 size 4096 nbytes 4096 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 1 flags 0x0(none) item 5 key (257 INODE_REF 256) itemoff 15839 itemsize 24 index 2 namelen 14 name: source_inlined item 6 key (257 EXTENT_DATA 0) itemoff 15770 itemsize 69 generation 8 type 0 (inline) inline extent data size 48 ram_bytes 4096 compression 1 (zlib) Which has an inline compressed extent at file offset 0, and its decompressed size is 4K, allowing us to reflink that 4K range to another location (which will not be compressed). If we do such reflink on a subpage system, it would fail like this: # xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest XFS_IOC_CLONE_RANGE: Input/output error [CAUSE] In zlib_decompress(), we didn't treat @start_byte as just a page offset, but also use it as an indicator on whether we should switch our output buffer. In reality, for subpage cases, although @start_byte can be non-zero, we should never switch input/output buffer, since the whole input/output buffer should never exceed one sector. Note: The above assumption is only not true if we're going to support multi-page sectorsize. Thus the current code using @start_byte as a condition to switch input/output buffer or finish the decompression is completely incorrect. [FIX] The fix involves several modifications: - Rename @start_byte to @dest_pgoff to properly express its meaning - Add an extra ASSERT() inside btrfs_decompress() to make sure the input/output size never exceeds one sector. - Use Z_FINISH flag to make sure the decompression happens in one go - Remove the loop needed to switch input/output buffers - Use correct destination offset inside the destination page - Consider early end as an error After the fix, even on 64K page sized aarch64, above reflink now works as expected: # xfs_io -f -c "reflink $mnt/source_inlined 0 60k 4k" $mnt/dest linked 4096/4096 bytes at offset 61440 And resulted a correct file layout: item 9 key (258 INODE_ITEM 0) itemoff 15542 itemsize 160 generation 10 transid 10 size 65536 nbytes 4096 block group 0 mode 100600 links 1 uid 0 gid 0 rdev 0 sequence 1 flags 0x0(none) item 10 key (258 INODE_REF 256) itemoff 15528 itemsize 14 index 3 namelen 4 name: dest item 11 key (258 XATTR_ITEM 3817753667) itemoff 15445 itemsize 83 location key (0 UNKNOWN.0 0) type XATTR transid 10 data_len 37 name_len 16 name: security.selinux data unconfined_u:object_r:unlabeled_t:s0 item 12 key (258 EXTENT_DATA 61440) itemoff 15392 itemsize 53 generation 10 type 1 (regular) extent data disk byte 13631488 nr 4096 extent data offset 0 nr 4096 ram 4096 extent compression 0 (none) Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: fix extent map use-after-free when adding pages to compressed bio

2024-08-03T06:54:13+00:00

commit 8e7860543a94784d744c7ce34b78a2e11beefa5c upstream. At add_ra_bio_pages() we are accessing the extent map to calculate 'add_size' after we dropped our reference on the extent map, resulting in a use-after-free. Fix this by computing 'add_size' before dropping our extent map reference. Reported-by: syzbot+853d80cba98ce1157ae6@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/000000000000038144061c6d18f2@google.com/ Fixes: 6a4049102055 ("btrfs: subpage: make add_ra_bio_pages() compatible") CC: stable@vger.kernel.org # 6.1+ Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: make btrfs_compressed_bioset static

2023-06-19T15:01:44+00:00

The 'btrfs_compressed_bioset' struct isn't exported outside of the fs/btrfs/compression.c file, so make it static to fix the following sparse warning: fs/btrfs/compression.c:40:16: warning: symbol 'btrfs_compressed_bioset' was not declared. Should it be static? Reviewed-by: Christoph Hellwig Signed-off-by: Ben Dooks Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: use btrfs_finish_ordered_extent to complete compressed writes

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

Use the btrfs_finish_ordered_extent helper to complete compressed writes using the bbio->ordered pointer instead of requiring an rbtree lookup in the otherwise equivalent btrfs_mark_ordered_io_finished called from btrfs_writepage_endio_finish_ordered. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add an ordered_extent pointer to struct btrfs_bio

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

Add a pointer to the ordered_extent to the existing union in struct btrfs_bio, so all code dealing with data write bios can just use a pointer dereference to retrieve the ordered_extent instead of doing multiple rbtree lookups per I/O. The reference to this ordered_extent is dropped at end I/O time, which implies that an extra one must be acquired when the bio is split. This also requires moving the btrfs_extract_ordered_extent call into btrfs_split_bio so that the invariant of always having a valid ordered_extent reference for the btrfs_bio is kept. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: pass an ordered_extent to btrfs_submit_compressed_write

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

btrfs_submit_compressed_write always operates on a single ordered_extent. Make that explicit by using btrfs_alloc_ordered_extent in the callers and passing the ordered_extent to btrfs_submit_compressed_write. This will help with storing and ordered_extent pointer in the btrfs_bio in subsequent patches. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: limit write bios to a single ordered extent

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

Currently buffered writeback bios are allowed to span multiple ordered_extents, although that basically never actually happens since commit 4a445b7b6178 ("btrfs: don't merge pages into bio if their page offset is not contiguous"). Supporting bios than span ordered_extents complicates the file checksumming code, and prevents us from adding an ordered_extent pointer to the btrfs_bio structure. Use the existing code to limit a bio to single ordered_extent for zoned device writes for all writes. This allows to remove the REQ_BTRFS_ONE_ORDERED flags, and the handling of multiple ordered_extents in btrfs_csum_one_bio. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: stop setting PageError in the data I/O path

2023-06-19T11:59:35+00:00

PageError is not used by the VFS/MM and deprecated because it uses up a page bit and has no coherent rules. Instead read errors are usually propagated by not setting or clearing the uptodate bit, and write errors are propagated through the address_space. Btrfs now only sets the flag and never clears it for data pages, so just remove all places setting it, and the subpage error bit. Note that the error propagation for superblock writes that work on the block device mapping still uses PageError for now, but that will be addressed in a separate series. Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: remove the mirror_num argument to btrfs_submit_compressed_read

2023-06-19T11:59:27+00:00

Given that read recovery for data I/O is handled in the storage layer, the mirror_num argument to btrfs_submit_compressed_read is always 0, so remove it. Reviewed-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: use SECTOR_SHIFT to convert physical offset to LBA

2023-06-19T11:59:23+00:00

Use SECTOR_SHIFT while converting a physical address to an LBA, makes it more readable. Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba