kernel/git/stable/linux.git/fs/btrfs/accessors.h, branch master

btrfs: allow mounting filesystems with remap-tree incompat flag

2026-02-03T06:54:35+00:00

If we encounter a filesystem with the remap-tree incompat flag set, validate its compatibility with the other flags, and load the remap tree using the values that have been added to the superblock. The remap-tree feature depends on the free-space-tree, but no-holes and block-group-tree have been made dependencies to reduce the testing matrix. Similarly I'm not aware of any reason why mixed-bg and zoned would be incompatible with remap-tree, but this is blocked for the time being until it can be fully tested. Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: add extended version of struct block_group_item

2026-02-03T06:54:34+00:00

Add a struct btrfs_block_group_item_v2, which is used in the block group tree if the remap-tree incompat flag is set. This adds two new fields to the block group item: `remap_bytes` and `identity_remap_count`. `remap_bytes` records the amount of data that's physically within this block group, but nominally in another, remapped block group. This is necessary because this data will need to be moved first if this block group is itself relocated. If `remap_bytes` > 0, this is an indicator to the relocation thread that it will need to search the remap-tree for backrefs. A block group must also have `remap_bytes` == 0 before it can be dropped. `identity_remap_count` records how many identity remap items are located in the remap tree for this block group. When relocation is begun for this block group, this is set to the number of holes in the free-space tree for this range. As identity remaps are converted into actual remaps by the relocation process, this number is decreased. Once it reaches 0, either because of relocation or because extents have been deleted, the block group has been fully remapped and its chunk's device extents are removed. Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: add definitions and constants for remap-tree

2026-02-03T06:54:02+00:00

Add an incompat flag for the new remap-tree feature, and the constants and definitions needed to support it. Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: headers cleanup to remove unnecessary local includes

2025-11-24T21:34:52+00:00

[BUG] When I tried to remove btrfs_bio::fs_info and use btrfs_bio::inode to grab the fs_info, the header "btrfs_inode.h" is needed to access the full btrfs_inode structure. Then btrfs will fail to compile. [CAUSE] There is a recursive including chain: "bio.h" -> "btrfs_inode.h" -> "extent_map.h" -> "compression.h" -> "bio.h" That recursive including is causing problems for btrfs. [ENHANCEMENT] To reduce the risk of recursive including: - Remove unnecessary local includes from btrfs headers Either the included header is pulled in by other headers, or is completely unnecessary. - Remove btrfs local includes if the header only requires a pointer In that case let the implementing C file to pull the required header. This is especially important for headers like "btrfs_inode.h" which pulls in a lot of other btrfs headers, thus it's a mine field of recursive including. - Remove unnecessary temporary structure definition Either if we have included the header defining the structure, or completely unused. Now including "btrfs_inode.h" inside "bio.h" is completely fine, although "btrfs_inode.h" still includes "extent_map.h", but that header only includes "fs.h", no more chain back to "bio.h". Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: accessors: delete token versions of set/get helpers

2025-07-21T22:05:00+00:00

Once upon a time there was a need to cache address of extent buffer pages, as it was a costly operation (map_private_extent_buffer(), cfed81a04eb555 ("Btrfs: add the ability to cache a pointer into the eb")). This was not even due to use of HIGHMEM, this had been removed before that due to possible locking issues (a65917156e3459 ("Btrfs: stop using highmem for extent_buffers")). Over time the amount of work in the set/get helpers got reduced and became quite straightforward bounds checking with an unaligned read/write, commit db3756c879773c ("btrfs: remove unused map_private_extent_buffer"). The actual caching of the page_address()/folio_address() in the token was more work for very little gain. This depended on subsequent access into the same page/folio, otherwise the cached pointer had to be updated. For metadata-heavy operations this showed up in the 'perf top' profile where the btrfs_get_token_32() calls were at the top, on my testing machine consuming about 2-3%. The other generic 32/64 bit helpers also appeared in the profile with similar fraction. After removing use of the token helpers we can remove them completely, this leads to reduction of btrfs.ko by 6.7KiB on release config. text data bss dec hex filename 1463289 115665 16088 1595042 1856a2 pre/btrfs.ko 1456601 115665 16088 1588354 183c82 post/btrfs.ko DELTA: -6688 Reviewed-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: update include and forward declarations in headers

2025-03-18T19:35:43+00:00

Pass over all header files and add missing forward declarations, includes or fix include types. Signed-off-by: David Sterba

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h

btrfs: remove raid-stripe-tree encoding field from stripe_extent

2024-07-11T13:33:28+00:00

Remove the encoding field from 'struct btrfs_stripe_extent'. It was originally intended to encode the RAID type as well as if we're a data or a parity stripe. But the RAID type can be inferred form the block-group and the data vs. parity differentiation can be done easier with adding a new key type for parity stripes in the RAID stripe tree. Signed-off-by: Johannes Thumshirn Signed-off-by: David Sterba

btrfs: constify parameters of write_eb_member() and its users

2024-07-11T13:33:19+00:00

Reported by 'gcc -Wcast-qual', the argument from which write_extent_buffer() reads data to write to the eb should be const. In addition the const needs to be also added to __write_extent_buffer() local buffers. All callers of write_eb_member() can now be updated to use const for the input buffer structure or type. Reviewed-by: Boris Burkov Reviewed-by: Anand Jain Reviewed-by: Naohiro Aota Signed-off-by: David Sterba

btrfs: keep const when returning value from get_unaligned_le8()

2024-07-11T13:33:19+00:00

This was reported by 'gcc -Wcast-qual', the get_unaligned_le8() simply returns the argument and there's no reason to drop the cast. Reviewed-by: Boris Burkov Reviewed-by: Anand Jain Reviewed-by: Naohiro Aota Signed-off-by: David Sterba