kernel/linux.git/fs/btrfs/relocation.h, branch v7.0.10

btrfs: handle setting up relocation of block group with remap-tree

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

Handle the preliminary work for relocating a block group in a filesystem with the remap-tree flag set. If the block group is SYSTEM btrfs_relocate_block_group() proceeds as it does already, as bootstrapping issues mean that these block groups have to be processed the existing way. Similarly with METADATA_REMAP blocks, which are dealt with in a later patch. Otherwise we walk the free-space tree for the block group in question, recording any holes. These get converted into identity remaps and placed in the remap tree, and the block group's REMAPPED flag is set. From now on no new allocations are possible within this block group, and any I/O to it will be funnelled through btrfs_translate_remap(). We store the number of identity remaps in `identity_remap_count`, so that we know when we've removed the last one and the block group is fully remapped. The change in btrfs_read_roots() is because data relocations no longer rely on the data reloc tree as a hidden subvolume in which to do snapshots. (Thanks to Sun YangKai for his suggestions.) Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: handle deletions from remapped block group

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

Handle the case where we free an extent from a block group that has the REMAPPED flag set. Because the remap tree is orthogonal to the extent tree, for data this may be within any number of identity remaps or actual remaps. If we're freeing a metadata node, this will be wholly inside one or the other. btrfs_remove_extent_from_remap_tree() searches the remap tree for the remaps that cover the range in question, then calls remove_range_from_remap_tree() for each one, to punch a hole in the remap and adjust the free-space tree. For an identity remap, remove_range_from_remap_tree() will adjust the block group's `identity_remap_count` if this changes. If it reaches zero we mark the block group as fully remapped. For an identity remap, remove_range_from_remap_tree() will adjust the block group's `identity_remap_count` if this changes. If it reaches zero we mark the block group as fully remapped. Fully remapped block groups have their chunk stripes removed and their device extents freed, which makes the disk space available again to the chunk allocator. This happens asynchronously: in the cleaner thread for sync discard and nodiscard, and (in a later patch) in the discard worker for async discard. Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: redirect I/O for remapped block groups

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

Change btrfs_map_block() so that if the block group has the REMAPPED flag set, we call btrfs_translate_remap() to obtain a new address. btrfs_translate_remap() searches the remap tree for a range corresponding to the logical address passed to btrfs_map_block(). If it is within an identity remap, this part of the block group hasn't yet been relocated, and so we use the existing address. If it is within an actual remap, we subtract the start of the remap range and add the address of its destination, contained in the item's payload. Reviewed-by: Boris Burkov Signed-off-by: Mark Harmstone Signed-off-by: David Sterba

btrfs: don't print relocation messages from auto reclaim

2025-07-21T22:09:22+00:00

When BTRFS is doing automatic block-group reclaim, it is spamming the kernel log messages a lot. Add a 'verbose' parameter to btrfs_relocate_chunk() and btrfs_relocate_block_group() to control the verbosity of these log message. This way the old behaviour of printing log messages on a user-space initiated balance operation can be kept while excessive log spamming due to auto reclaim is mitigated. Reviewed-by: Boris Burkov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add forward declarations and headers, part 1

2024-03-04T15:24:49+00:00

Do a cleanup in the short headers: - add forward declarations for types referenced by pointers - add includes when types need them This fixes potential compilation problems if the headers are reordered or the missing includes are not provided indirectly. Signed-off-by: David Sterba

btrfs: relocation: constify parameters where possible

2023-10-12T14:44:13+00:00

Lots of the functions in relocation.c don't change pointer parameters but lack the annotations. Add them and reformat according to current coding style if needed. Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba

btrfs: relocation: return bool from btrfs_should_ignore_reloc_root

2023-10-12T14:44:13+00:00

btrfs_should_ignore_reloc_root() is a predicate so it should return bool. Reviewed-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Signed-off-by: David Sterba

btrfs: pass an ordered_extent to btrfs_reloc_clone_csums

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

Both callers of btrfs_reloc_clone_csums allocate the ordered_extent that btrfs_reloc_clone_csums operates on. Switch them to use btrfs_alloc_ordered_extent instead of btrfs_add_ordered_extent and pass the ordered_extent to btrfs_reloc_clone_csums instead of doing an extra lookup. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: output affected files when relocation fails

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

[PROBLEM] When relocation fails (mostly due to checksum mismatch), we only got very cryptic error messages like: BTRFS info (device dm-4): relocating block group 13631488 flags data BTRFS warning (device dm-4): csum failed root -9 ino 257 off 0 csum 0x373e1ae3 expected csum 0x98757625 mirror 1 BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0 BTRFS info (device dm-4): balance: ended with status: -5 The end user has to decipher the above messages and use various tools to locate the affected files and find a way to fix the problem (mostly deleting the file). This is not an easy work even for experienced developer, not to mention the end users. [SCRUB IS DOING BETTER] By contrast, scrub is providing much better error messages: BTRFS error (device dm-4): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488 BTRFS warning (device dm-4): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file) BTRFS info (device dm-4): scrub: finished on devid 1 with status: 0 Which provides the affected files directly to the end user. [IMPROVEMENT] Instead of the generic data checksum error messages, which is not doing a good job for data reloc inodes, this patch introduce a scrub like backref walking based solution. When a sector fails its checksum for data reloc inode, we go the following workflow: - Get the real logical bytenr For data reloc inode, the file offset is the offset inside the block group. Thus the real logical bytenr is @file_off + @block_group->start. - Do an extent type check If it's tree blocks it's much easier to handle, just go through all the tree block backref. - Do a backref walk and inode path resolution for data extents This is mostly the same as scrub. But unfortunately we can not reuse the same function as the output format is different. Now the new output would be more user friendly: BTRFS info (device dm-4): relocating block group 13631488 flags data BTRFS warning (device dm-4): csum failed root -9 ino 257 off 0 logical 13631488 csum 0x373e1ae3 expected csum 0x98757625 mirror 1 BTRFS warning (device dm-4): checksum error at logical 13631488 mirror 1 root 5 inode 257 offset 0 length 4096 links 1 (path: file) BTRFS error (device dm-4): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 2, gen 0 BTRFS info (device dm-4): balance: ended with status: -5 Reviewed-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: move relocation prototypes into relocation.h

2022-12-05T17:00:47+00:00

Move these out of ctree.h into relocation.h to cut down on code in ctree.h Reviewed-by: Johannes Thumshirn Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba