kernel/git/stable/linux.git/fs/btrfs/free-space-tree.c, branch master

btrfs: switch local indicator variables to bools

2026-06-09T16:22:46+00:00

For all local indicator variables do simple switch to bool, done on all files. Signed-off-by: David Sterba

btrfs: free-space-tree: reject mismatched extent and bitmap items

2026-06-08T13:53:32+00:00

btrfs_load_free_space_tree() reads FREE_SPACE_INFO once and then chooses the bitmap or extent loader for all following free-space records until the next FREE_SPACE_INFO item. Those loaders currently enforce the selected record type only with ASSERT(). On production builds without CONFIG_BTRFS_ASSERT, a malformed free-space tree can therefore be decoded in the wrong mode. An EXTENT item can reach btrfs_free_space_test_bit() as bitmap data, while a BITMAP item can be added as a full free extent. The latter corrupts the in-memory free-space cache and the former can read beyond the item payload. Sanitizer validation reported: general protection fault Call trace: assert_eb_folio_uptodate() (fs/btrfs/extent_io.c:4134) extent_buffer_test_bit() (?:?) btrfs_free_space_test_bit() (fs/btrfs/free-space-tree.c:518) srso_alias_return_thunk() (arch/x86/include/asm/nospec-branch.h:375) __entry_text_end() (?:?) __asan_memcpy() (mm/kasan/shadow.c:103) read_extent_buffer() (?:?) load_free_space_bitmaps() (fs/btrfs/free-space-tree.c:1548) btrfs_get_32() (fs/btrfs/free-space-tree.c:?) btrfs_set_16() (fs/btrfs/free-space-tree.c:?) kmem_cache_alloc_noprof() (?:?) btrfs_load_free_space_tree() (fs/btrfs/free-space-tree.c:1685) load_free_space_tree_for_test() (?:?) rcu_disable_urgency_upon_qs() (kernel/rcu/tree.c:721) vprintk_emit() (?:?) __up_write() (kernel/locking/rwsem.c:1401) clone_commit_root_for_test() (?:?) test_extent_as_bitmap_mode_mismatch() (?:?) kmem_cache_free() (?:?) btrfs_free_path() (fs/btrfs/free-space-tree.c:1449) __add_block_group_free_space() (fs/btrfs/free-space-tree.c:20) run_test() (?:?) do_raw_spin_unlock() (?:?) btrfs_test_free_space_tree() (fs/btrfs/tests/free-space-tree-tests.c:547) btrfs_test_qgroups() (fs/btrfs/tests/qgroup-tests.c:462) btrfs_run_sanity_tests() (fs/btrfs/free-space-tree.c:?) init_btrfs_fs() (fs/btrfs/super.c:2690) do_one_initcall() (init/main.c:1382) __kasan_kmalloc() (?:?) rcu_is_watching() (?:?) do_initcalls() (init/main.c:1457) kernel_init_freeable() (init/main.c:1674) kernel_init() (init/main.c:1584) ret_from_fork() (?:?) __switch_to() (?:?) ret_from_fork_asm() (?:?) Validate every post-info key before decoding it. Reject keys whose type does not match the mode selected by FREE_SPACE_INFO, and reject keys whose range extends past the block group, returning -EUCLEAN instead of feeding the wrong record type to the bitmap or extent decoder. Also reject zero-length FREE_SPACE_EXTENT items in tree-checker, matching the existing FREE_SPACE_BITMAP zero-length check. This keeps the loader range check simple and prevents a zero-length extent item from being a valid on-disk free-space record. Reviewed-by: Qu Wenruo Signed-off-by: Zhang Cen Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add missing unlikely to if branches leading to a DEBUG_WARN()

2026-06-08T13:53:30+00:00

If statement branches that lead to a DEBUG_WARN() are unexpected to happen and in most places we surround their expressions with the unlikely tag, however a few places are missing. Add the unlikely tag to those missing places to make it explicit to a reader that it's not expected and to hint the compiler to generate better code. Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: handle unexpected free-space-tree key types

2026-04-21T02:02:02+00:00

Replace the conditional assertions with proper error handling and transaction abort if we find an unexpected key type in the free space tree. Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba

btrfs: check for NULL root after calls to btrfs_extent_root()

2026-03-17T10:22:49+00:00

btrfs_extent_root() can return a NULL pointer in case the root we are looking for is not in the rb tree that tracks roots. So add checks to every caller that is missing such check to log a message and return an error. The same applies to callers of btrfs_block_group_root(), since it calls btrfs_extent_root(). Reported-by: Chris Mason Link: https://lore.kernel.org/linux-btrfs/20260208161657.3972997-1-clm@meta.com/ Reviewed-by: Boris Burkov Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: use the btrfs_block_group_end() helper everywhere

2026-02-03T06:54:36+00:00

We have a helper to calculate a block group's exclusive end offset, but we only use it in some places. Update every site that open codes the calculation to use the helper. Reviewed-by: Johannes Thumshirn Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

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: update outdated comment in __add_block_group_free_space()

2026-02-03T06:51:42+00:00

The function add_block_group_free_space() was renamed btrfs_add_block_group_free_space() by commit 6fc5ef782988 ("btrfs: add btrfs prefix to free space tree exported functions"). Update the comment accordingly. Do some reorganization of the next few lines to keep the comment within 80 characters. Signed-off-by: Julia Lawall Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add mount time auto fix for orphan fst entries

2026-02-03T06:51:34+00:00

[BUG] Before btrfs-progs v6.16.1 release, mkfs.btrfs can leave free space tree entries for deleted chunks: # mkfs.btrfs -f -O fst $dev # btrfs ins dump-tree -t chunk $dev btrfs-progs v6.16 chunk tree leaf 22036480 items 4 free space 15781 generation 8 owner CHUNK_TREE leaf 22036480 flags 0x1(WRITTEN) backref revision 1 item 0 key (DEV_ITEMS DEV_ITEM 1) itemoff 16185 itemsize 98 item 1 key (FIRST_CHUNK_TREE CHUNK_ITEM 13631488) itemoff 16105 itemsize 80 ^^^ The first chunk is at 13631488 item 2 key (FIRST_CHUNK_TREE CHUNK_ITEM 22020096) itemoff 15993 itemsize 112 item 3 key (FIRST_CHUNK_TREE CHUNK_ITEM 30408704) itemoff 15881 itemsize 112 # btrfs ins dump-tree -t free-space-tree $dev btrfs-progs v6.16 free space tree key (FREE_SPACE_TREE ROOT_ITEM 0) leaf 30556160 items 13 free space 15918 generation 8 owner FREE_SPACE_TREE leaf 30556160 flags 0x1(WRITTEN) backref revision 1 item 0 key (1048576 FREE_SPACE_INFO 4194304) itemoff 16275 itemsize 8 free space info extent count 1 flags 0 item 1 key (1048576 FREE_SPACE_EXTENT 4194304) itemoff 16275 itemsize 0 free space extent item 2 key (5242880 FREE_SPACE_INFO 8388608) itemoff 16267 itemsize 8 free space info extent count 1 flags 0 item 3 key (5242880 FREE_SPACE_EXTENT 8388608) itemoff 16267 itemsize 0 free space extent ^^^ Above 4 items are all before the first chunk. item 4 key (13631488 FREE_SPACE_INFO 8388608) itemoff 16259 itemsize 8 free space info extent count 1 flags 0 item 5 key (13631488 FREE_SPACE_EXTENT 8388608) itemoff 16259 itemsize 0 free space extent ... This can trigger btrfs check errors. [CAUSE] It's a bug in free space tree implementation of btrfs-progs, which doesn't delete involved fst entries for the to-be-deleted chunk/block group. [ENHANCEMENT] The mostly common fix is to clear the space cache and rebuild it, but that requires a ro->rw remount which may not be possible for rootfs, and also relies on users to use "clear_cache" mount option manually. Here introduce a kernel fix for it, which will delete any entries that is before the first block group automatically at the first RW mount. For filesystems without such problem, the overhead is just a single tree search and no modification to the free space tree, thus the overhead should be minimal. Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: merge setting ret and return ret

2026-02-03T05:38:33+00:00

In many places we have pattern: ret = ...; return ret; This can be simplified to a direct return, removing 'ret' if not otherwise needed. The places in self tests are not converted so we can add more test cases without changing surrounding code (extent-map-tests.c:test_case_4()). Signed-off-by: David Sterba