summaryrefslogtreecommitdiff
path: root/fs/btrfs/free-space-tree.c
AgeCommit message (Collapse)Author
2026-06-09btrfs: switch local indicator variables to boolsDavid Sterba
For all local indicator variables do simple switch to bool, done on all files. Signed-off-by: David Sterba <dsterba@suse.com>
2026-06-08btrfs: free-space-tree: reject mismatched extent and bitmap itemsZhang Cen
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 <wqu@suse.com> Signed-off-by: Zhang Cen <rollkingzzc@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-06-08btrfs: add missing unlikely to if branches leading to a DEBUG_WARN()Filipe Manana
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 <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21btrfs: handle unexpected free-space-tree key typesDavid Sterba
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 <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-03-17btrfs: check for NULL root after calls to btrfs_extent_root()Filipe Manana
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 <clm@meta.com> Link: https://lore.kernel.org/linux-btrfs/20260208161657.3972997-1-clm@meta.com/ Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: use the btrfs_block_group_end() helper everywhereFilipe Manana
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 <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: handle setting up relocation of block group with remap-treeMark Harmstone
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 <boris@bur.io> Signed-off-by: Mark Harmstone <mark@harmstone.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: update outdated comment in __add_block_group_free_space()Julia Lawall
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 <Julia.Lawall@inria.fr> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: add mount time auto fix for orphan fst entriesQu Wenruo
[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 <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-02-03btrfs: merge setting ret and return retDavid Sterba
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 <dsterba@suse.com>
2025-11-25btrfs: remaining BTRFS_PATH_AUTO_FREE conversionsDavid Sterba
Do the remaining btrfs_path conversion to the auto cleaning, this seems to be the last one. Most of the conversions are trivial, only adding the declaration and removing the freeing, or changing the goto patterns to return. There are some functions with many changes, like __btrfs_free_extent(), btrfs_remove_from_free_space_tree() or btrfs_add_to_free_space_tree() but it still follows the same pattern. Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: use bool type for btrfs_path members used as booleansFilipe Manana
Many fields of struct btrfs_path are used as booleans but their type is an unsigned int (of one 1 bit width to save space). Change the type to bool keeping the :1 suffix so that they combine with the previous u8 fields in order to save space. This makes the code more clear by using explicit true/false and more in line with the preferred style, preserving the size of the structure. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: fix comment in alloc_bitmap() and drop stale TODORajeev Tapadia
All callers of alloc_bitmap() hold a transaction handle, so GFP_NOFS is needed to avoid deadlocks on recursion. Update the comment and drop the stale TODO. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Rajeev Tapadia <rtapadia730@gmail.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-11-24btrfs: ignore ENOMEM from alloc_bitmap()Boris Burkov
btrfs_convert_free_space_to_bitmaps() and btrfs_convert_free_space_to_extents() both allocate a bitmap struct with: bitmap_size = free_space_bitmap_size(fs_info, block_group->length); bitmap = alloc_bitmap(bitmap_size); if (!bitmap) { ret = -ENOMEM; btrfs_abort_transaction(trans); return ret; } This conversion is done based on a heuristic and the check triggers each time we call update_free_space_extent_count() on a block group (each time we add/remove an extent or modify a bitmap). Furthermore, nothing relies on maintaining some invariant of bitmap density, it's just an optimization for space usage. Therefore, it is safe to simply ignore any memory allocation errors that occur, rather than aborting the transaction and leaving the fs read only. Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-10-13btrfs: do not assert we found block group item when creating free space treeFilipe Manana
Currently, when building a free space tree at populate_free_space_tree(), if we are not using the block group tree feature, we always expect to find block group items (either extent items or a block group item with key type BTRFS_BLOCK_GROUP_ITEM_KEY) when we search the extent tree with btrfs_search_slot_for_read(), so we assert that we found an item. However this expectation is wrong since we can have a new block group created in the current transaction which is still empty and for which we still have not added the block group's item to the extent tree, in which case we do not have any items in the extent tree associated to the block group. The insertion of a new block group's block group item in the extent tree happens at btrfs_create_pending_block_groups() when it calls the helper insert_block_group_item(). This typically is done when a transaction handle is released, committed or when running delayed refs (either as part of a transaction commit or when serving tickets for space reservation if we are low on free space). So remove the assertion at populate_free_space_tree() even when the block group tree feature is not enabled and update the comment to mention this case. Syzbot reported this with the following stack trace: BTRFS info (device loop3 state M): rebuilding free space tree assertion failed: ret == 0 :: 0, in fs/btrfs/free-space-tree.c:1115 ------------[ cut here ]------------ kernel BUG at fs/btrfs/free-space-tree.c:1115! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 6352 Comm: syz.3.25 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:populate_free_space_tree+0x700/0x710 fs/btrfs/free-space-tree.c:1115 Code: ff ff e8 d3 (...) RSP: 0018:ffffc9000430f780 EFLAGS: 00010246 RAX: 0000000000000043 RBX: ffff88805b709630 RCX: fea61d0e2e79d000 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffffc9000430f8b0 R08: ffffc9000430f4a7 R09: 1ffff92000861e94 R10: dffffc0000000000 R11: fffff52000861e95 R12: 0000000000000001 R13: 1ffff92000861f00 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f424d9fe6c0(0000) GS:ffff888125afc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd78ad212c0 CR3: 0000000076d68000 CR4: 00000000003526f0 Call Trace: <TASK> btrfs_rebuild_free_space_tree+0x1ba/0x6d0 fs/btrfs/free-space-tree.c:1364 btrfs_start_pre_rw_mount+0x128f/0x1bf0 fs/btrfs/disk-io.c:3062 btrfs_remount_rw fs/btrfs/super.c:1334 [inline] btrfs_reconfigure+0xaed/0x2160 fs/btrfs/super.c:1559 reconfigure_super+0x227/0x890 fs/super.c:1076 do_remount fs/namespace.c:3279 [inline] path_mount+0xd1a/0xfe0 fs/namespace.c:4027 do_mount fs/namespace.c:4048 [inline] __do_sys_mount fs/namespace.c:4236 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4213 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f424e39066a Code: d8 64 89 02 (...) RSP: 002b:00007f424d9fde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f424d9fdef0 RCX: 00007f424e39066a RDX: 0000200000000180 RSI: 0000200000000380 RDI: 0000000000000000 RBP: 0000200000000180 R08: 00007f424d9fdef0 R09: 0000000000000020 R10: 0000000000000020 R11: 0000000000000246 R12: 0000200000000380 R13: 00007f424d9fdeb0 R14: 0000000000000000 R15: 00002000000002c0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- Reported-by: syzbot+884dc4621377ba579a6f@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/68dc3dab.a00a0220.102ee.004e.GAE@google.com/ Fixes: a5ed91828518 ("Btrfs: implement the free space B-tree") CC: <stable@vger.kernel.org> # 6.1.x: 1961d20f6fa8: btrfs: fix assertion when building free space tree CC: <stable@vger.kernel.org> # 6.1.x Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23btrfs: add unlikely annotations to branches leading to transaction abortDavid Sterba
The unlikely() annotation is a static prediction hint that compiler may use to reorder code out of hot path. We use it elsewhere (namely tree-checker.c) for error branches that almost never happen. Transaction abort is one such error, the btrfs_abort_transaction() inlines code to check the state and print a warning, this ought to be out of the hot path. The most common pattern is when transaction abort is called after checking a return value and the control flow leads to a quick return. In other cases it may not be necessary to add unlikely() e.g. when the function returns anyway or the control flow is not changed noticeably. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-09-23btrfs: add unlikely annotations to branches leading to EIODavid Sterba
The unlikely() annotation is a static prediction hint that compiler may use to reorder code out of hot path. We use it elsewhere (namely tree-checker.c) for error branches that almost never happen, where EIO is one of them. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: cache if we are using free space bitmaps for a block groupFilipe Manana
Every time we add free space to the free space tree or we remove free space from the free space tree, we do a lookup for the block group's free space info item in the free space tree. This takes time, navigating the btree and we may block either on IO when reading extent buffers from disk or on extent buffer lock contention due to concurrency. Instead of doing this lookup every time, cache the result in the block structure and use it after the first lookup. This adds two boolean members to the block group structure but doesn't increase the structure's size. The following script that runs fs_mark was used to measure the time spent on run_delayed_tree_ref(), since down that call chain we have calls to add and remove free space to/from the free space tree (calls to btrfs_add_to_free_space_tree() and btrfs_remove_from_free_space_tree()): $ cat test.sh #!/bin/bash DEV=/dev/nullb0 MNT=/mnt FILES=100000 THREADS=$(nproc --all) echo "performance" | \ tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor umount $DEV &> /dev/null mkfs.btrfs -f $DEV mount -o ssd $DEV $MNT OPTS="-S 0 -L 5 -n $FILES -s 0 -t $THREADS -k" for ((i = 1; i <= $THREADS; i++)); do OPTS="$OPTS -d $MNT/d$i" done fs_mark $OPTS umount $MNT This is a heavy metadata test as it's exercising only file creation, so a lot of allocations of metadata extents, creating delayed refs for adding new metadata extents and dropping existing ones due to COW. The results of the times it took to execute run_delayed_tree_ref(), in nanoseconds, are the following. Before this change: Range: 1868.000 - 6482857.000; Mean: 10231.430; Median: 7005.000; Stddev: 27993.173 Percentiles: 90th: 13342.000; 95th: 23279.000; 99th: 82448.000 1868.000 - 4222.038: 270696 ############ 4222.038 - 9541.029: 1201327 ##################################################### 9541.029 - 21559.383: 385436 ################# 21559.383 - 48715.063: 64942 ### 48715.063 - 110073.800: 31454 # 110073.800 - 248714.944: 8218 | 248714.944 - 561977.042: 1030 | 561977.042 - 1269798.254: 295 | 1269798.254 - 2869132.711: 116 | 2869132.711 - 6482857.000: 28 | After this change: Range: 1554.000 - 4557014.000; Mean: 9168.164; Median: 6391.000; Stddev: 21467.060 Percentiles: 90th: 12478.000; 95th: 20964.000; 99th: 72234.000 1554.000 - 3453.820: 219004 ############ 3453.820 - 7674.743: 980645 ##################################################### 7674.743 - 17052.574: 552486 ############################## 17052.574 - 37887.762: 68558 #### 37887.762 - 84178.322: 31557 ## 84178.322 - 187024.331: 12102 # 187024.331 - 415522.355: 1364 | 415522.355 - 923187.626: 256 | 923187.626 - 2051092.468: 125 | 2051092.468 - 4557014.000: 21 | Approximate improvement in the first four buckets is about 20%. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: add and use helper to determine if using bitmaps in free space treeFilipe Manana
When adding and removing free space to the free space tree, we need to lookup the respective block group's free info item in the free space tree, check its flags for the BTRFS_FREE_SPACE_USING_BITMAPS bit and then release the path. Move these steps into a helper function and use it in both sites. This will also help avoiding duplicate code in a subsequent change. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: use fs_info from local variable in btrfs_convert_free_space_to_extents()Filipe Manana
There's no need to dereference the block group to extract fs_info as we have already stored fs_info in a local variable. So use the local variable instead. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: avoid double slot decrement at btrfs_convert_free_space_to_extents()Filipe Manana
There's no need to subtract 1 from path->slots[0] and then decrement the slot, we can reduce the generated assembly code by decrementing the slot and then use it. Module size before: $ size fs/btrfs/btrfs.ko text data bss dec hex filename 1846220 162998 16136 2025354 1ee78a fs/btrfs/btrfs.ko Module size after: $ size fs/btrfs/btrfs.ko text data bss dec hex filename 1846204 162998 16136 2025338 1ee77a fs/btrfs/btrfs.ko Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: turn remove argument of modify_free_space_bitmap() to booleanFilipe Manana
The argument is used as a boolean, so switch its type from int to bool. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: rename free_space_set_bits() and make it less confusingFilipe Manana
The free_space_set_bits() is used both to set a range of bits or to clear range of bits, depending on the 'bit' argument value. So the name is very misleading since it's not used only to set bits. Furthermore the 'bit' argument is an integer when a boolean is all that is needed plus its name is singular, which gives the idea the function operates on a single bit and not on a range of bits. So rename the function to free_space_modify_bits(), rename the 'bit' argument to 'set_bits' and turn the argument to bool instead of int. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: add btrfs prefix to free space tree exported functionsFilipe Manana
A few of the free space tree exported functions have a 'btrfs_' prefix in their name, but most don't. Not only is this inconsistent, the preferred style is to have such a prefix, to avoid potential collisions in the future with other kernel code and offer a somewhat better readibility by making it obvious in calls sites that we are calling btrfs specific code. So add the 'btrfs_' prefix to all free space tree functions that are missing it. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from load_free_space_extents()Filipe Manana
All we do under the label is to return, so there's no point in having it, just return directly whenever we get an error. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from load_free_space_bitmaps()Filipe Manana
All we do under the label is to return, so there's no point in having it, just return directly whenever we get an error. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from add_free_space_extent()Filipe Manana
All we do under the label is to return, so there's no point in having it, just return directly whenever we get an error. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from remove_free_space_extent()Filipe Manana
All we do under the label is to return, so there's no point in having it, just return directly whenever we get an error. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from modify_free_space_bitmap()Filipe Manana
All we do under the label is to return, so there's no point in having it, just return directly whenever we get an error. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: make free_space_test_bit() return a boolean insteadFilipe Manana
The function returns the result of another function that returns a boolean (extent_buffer_test_bit()), and all the callers need is a boolean an not an integer. So change its return type from int to bool, and modify the callers to store results in booleans instead of integers, which also makes them simpler. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: make extent_buffer_test_bit() return a boolean insteadFilipe Manana
All the callers want is to determine if a bit is set and all of them call the function and do a double negation (!!) on its result to get a boolean. So change it to return a boolean and simplify callers. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from update_free_space_extent_count()Filipe Manana
Just return directly, we don't need the label since all we do under it is to return. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: remove pointless out label from add_new_free_space_info()Filipe Manana
We can just return directly if btrfs_insert_empty_item() fails, there is no need to release the path before returning, as all callers (or upper in the call chain) will free the path if they get an error from the call to add_new_free_space_info(), which is also a common pattern everywhere in btrfs. Finally there's no need to set 'ret' to 0 if the call to btrfs_insert_empty_item() didn't fail, since 'ret' is already 0. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: check BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE at __add_block_group_free_space()Filipe Manana
Every caller of __add_block_group_free_space() is checking if the flag BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE is set before calling it. This is duplicate code and it's prone to some mistake in case we add more callers in the future. So move the check for that flag into the start of __add_block_group_free_space(), and, as a consequence, the path allocation from add_block_group_free_space() is moved into __add_block_group_free_space(), to preserve the behaviour of allocating a path only if the flag BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE is set. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: always abort transaction on failure to add block group to free space treeFilipe Manana
Only one of the callers of __add_block_group_free_space() aborts the transaction if the call fails, while the others don't do it and it's either never done up the call chain or much higher in the call chain. So make sure we abort the transaction at __add_block_group_free_space() if it fails, which brings a couple benefits: 1) If some call chain never aborts the transaction, we avoid having some metadata inconsistency because BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE is cleared when we enter __add_block_group_free_space() and therefore __add_block_group_free_space() is never called again to add the block group items to the free space tree, since the function is only called when that flag is set in a block group; 2) If the call chain already aborts the transaction, then we get a better trace that points to the exact step from __add_block_group_free_space() which failed, which is better for analysis. So abort the transaction at __add_block_group_free_space() if any of its steps fails. CC: stable@vger.kernel.org # 6.6+ Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: move transaction aborts to the error site in add_block_group_free_space()David Sterba
Transaction aborts should be done next to the place the error happens, which was not done in add_block_group_free_space(). Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-07-21btrfs: move transaction aborts to the error site in ↵David Sterba
remove_block_group_free_space() Transaction aborts should be done next to the place the error happens, which was not done in remove_block_group_free_space(). Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-06-27btrfs: fix failure to rebuild free space tree using multiple transactionsFilipe Manana
If we are rebuilding a free space tree, while modifying the free space tree we may need to allocate a new metadata block group. If we end up using multiple transactions for the rebuild, when we call btrfs_end_transaction() we enter btrfs_create_pending_block_groups() which calls add_block_group_free_space() to add items to the free space tree for the block group. Then later during the free space tree rebuild, at btrfs_rebuild_free_space_tree(), we may find such new block groups and call populate_free_space_tree() for them, which fails with -EEXIST because there are already items in the free space tree. Then we abort the transaction with -EEXIST at btrfs_rebuild_free_space_tree(). Notice that we say "may find" the new block groups because a new block group may be inserted in the block groups rbtree, which is being iterated by the rebuild process, before or after the current node where the rebuild process is currently at. Syzbot recently reported such case which produces a trace like the following: ------------[ cut here ]------------ BTRFS: Transaction aborted (error -17) WARNING: CPU: 1 PID: 7626 at fs/btrfs/free-space-tree.c:1341 btrfs_rebuild_free_space_tree+0x470/0x54c fs/btrfs/free-space-tree.c:1341 Modules linked in: CPU: 1 UID: 0 PID: 7626 Comm: syz.2.25 Not tainted 6.15.0-rc7-syzkaller-00085-gd7fa1af5b33e-dirty #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : btrfs_rebuild_free_space_tree+0x470/0x54c fs/btrfs/free-space-tree.c:1341 lr : btrfs_rebuild_free_space_tree+0x470/0x54c fs/btrfs/free-space-tree.c:1341 sp : ffff80009c4f7740 x29: ffff80009c4f77b0 x28: ffff0000d4c3f400 x27: 0000000000000000 x26: dfff800000000000 x25: ffff70001389eee8 x24: 0000000000000003 x23: 1fffe000182b6e7b x22: 0000000000000000 x21: ffff0000c15b73d8 x20: 00000000ffffffef x19: ffff0000c15b7378 x18: 1fffe0003386f276 x17: ffff80008f31e000 x16: ffff80008adbe98c x15: 0000000000000001 x14: 1fffe0001b281550 x13: 0000000000000000 x12: 0000000000000000 x11: ffff60001b281551 x10: 0000000000000003 x9 : 1c8922000a902c00 x8 : 1c8922000a902c00 x7 : ffff800080485878 x6 : 0000000000000000 x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff80008047843c x2 : 0000000000000001 x1 : ffff80008b3ebc40 x0 : 0000000000000001 Call trace: btrfs_rebuild_free_space_tree+0x470/0x54c fs/btrfs/free-space-tree.c:1341 (P) btrfs_start_pre_rw_mount+0xa78/0xe10 fs/btrfs/disk-io.c:3074 btrfs_remount_rw fs/btrfs/super.c:1319 [inline] btrfs_reconfigure+0x828/0x2418 fs/btrfs/super.c:1543 reconfigure_super+0x1d4/0x6f0 fs/super.c:1083 do_remount fs/namespace.c:3365 [inline] path_mount+0xb34/0xde0 fs/namespace.c:4200 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount fs/namespace.c:4409 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4409 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 irq event stamp: 330 hardirqs last enabled at (329): [<ffff80008048590c>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1525 [inline] hardirqs last enabled at (329): [<ffff80008048590c>] finish_lock_switch+0xb0/0x1c0 kernel/sched/core.c:5130 hardirqs last disabled at (330): [<ffff80008adb9e60>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:511 softirqs last enabled at (10): [<ffff8000801fbf10>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (8): [<ffff8000801fbedc>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- Fix this by flagging new block groups which had their free space tree entries already added and then skip them in the rebuild process. Also, since the rebuild may be triggered when doing a remount, make sure that when we clear an existing free space tree that we clear such flag from every existing block group, otherwise we would skip those block groups during the rebuild. Reported-by: syzbot+d0014fb0fc39c5487ae5@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/68460a54.050a0220.daf97.0af5.GAE@google.com/ Fixes: 882af9f13e83 ("btrfs: handle free space tree rebuild in multiple transactions") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-06-19btrfs: fix assertion when building free space treeFilipe Manana
When building the free space tree with the block group tree feature enabled, we can hit an assertion failure like this: BTRFS info (device loop0 state M): rebuilding free space tree assertion failed: ret == 0, in fs/btrfs/free-space-tree.c:1102 ------------[ cut here ]------------ kernel BUG at fs/btrfs/free-space-tree.c:1102! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Modules linked in: CPU: 1 UID: 0 PID: 6592 Comm: syz-executor322 Not tainted 6.15.0-rc7-syzkaller-gd7fa1af5b33e #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : populate_free_space_tree+0x514/0x518 fs/btrfs/free-space-tree.c:1102 lr : populate_free_space_tree+0x514/0x518 fs/btrfs/free-space-tree.c:1102 sp : ffff8000a4ce7600 x29: ffff8000a4ce76e0 x28: ffff0000c9bc6000 x27: ffff0000ddfff3d8 x26: ffff0000ddfff378 x25: dfff800000000000 x24: 0000000000000001 x23: ffff8000a4ce7660 x22: ffff70001499cecc x21: ffff0000e1d8c160 x20: ffff0000e1cb7800 x19: ffff0000e1d8c0b0 x18: 00000000ffffffff x17: ffff800092f39000 x16: ffff80008ad27e48 x15: ffff700011e740c0 x14: 1ffff00011e740c0 x13: 0000000000000004 x12: ffffffffffffffff x11: ffff700011e740c0 x10: 0000000000ff0100 x9 : 94ef24f55d2dbc00 x8 : 94ef24f55d2dbc00 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000a4ce6f98 x4 : ffff80008f415ba0 x3 : ffff800080548ef0 x2 : 0000000000000000 x1 : 0000000100000000 x0 : 000000000000003e Call trace: populate_free_space_tree+0x514/0x518 fs/btrfs/free-space-tree.c:1102 (P) btrfs_rebuild_free_space_tree+0x14c/0x54c fs/btrfs/free-space-tree.c:1337 btrfs_start_pre_rw_mount+0xa78/0xe10 fs/btrfs/disk-io.c:3074 btrfs_remount_rw fs/btrfs/super.c:1319 [inline] btrfs_reconfigure+0x828/0x2418 fs/btrfs/super.c:1543 reconfigure_super+0x1d4/0x6f0 fs/super.c:1083 do_remount fs/namespace.c:3365 [inline] path_mount+0xb34/0xde0 fs/namespace.c:4200 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount fs/namespace.c:4409 [inline] __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4409 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Code: f0047182 91178042 528089c3 9771d47b (d4210000) ---[ end trace 0000000000000000 ]--- This happens because we are processing an empty block group, which has no extents allocated from it, there are no items for this block group, including the block group item since block group items are stored in a dedicated tree when using the block group tree feature. It also means this is the block group with the highest start offset, so there are no higher keys in the extent root, hence btrfs_search_slot_for_read() returns 1 (no higher key found). Fix this by asserting 'ret' is 0 only if the block group tree feature is not enabled, in which case we should find a block group item for the block group since it's stored in the extent root and block group item keys are greater than extent item keys (the value for BTRFS_BLOCK_GROUP_ITEM_KEY is 192 and for BTRFS_EXTENT_ITEM_KEY and BTRFS_METADATA_ITEM_KEY the values are 168 and 169 respectively). In case 'ret' is 1, we just need to add a record to the free space tree which spans the whole block group, and we can achieve this by making 'ret == 0' as the while loop's condition. Reported-by: syzbot+36fae25c35159a763a2a@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/6841dca8.a00a0220.d4325.0020.GAE@google.com/ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: move transaction aborts to the error site in add_to_free_space_tree()David Sterba
Transaction aborts should be done next to the place the error happens, which was not done in add_to_free_space_tree(). Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: move transaction aborts to the error site in ↵David Sterba
remove_from_free_space_tree() Transaction aborts should be done next to the place the error happens, which was not done in remove_from_free_space_tree(). Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: move transaction aborts to the error site in ↵David Sterba
convert_free_space_to_extents() Transaction aborts should be done next to the place the error happens, which was not done in convert_free_space_to_extents(). The DEBUG_WARN() is removed because we get the abort message. Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: move transaction aborts to the error site in ↵David Sterba
convert_free_space_to_bitmaps() Transaction aborts should be done next to the place the error happens, which was not done in convert_free_space_to_bitmaps(). The DEBUG_WARN() is removed because we get the abort message. Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15btrfs: convert ASSERT(0) with handled errors to DEBUG_WARN()David Sterba
The use of ASSERT(0) is maybe useful for some cases but more like a notice for developers. Assertions can be compiled in independently so convert it to a debugging helper. The difference is that it's just a warning and will not end up in BUG(). The converted cases are in connection with proper error handling. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-03-18btrfs: use BTRFS_PATH_AUTO_FREE in load_free_space_tree()David Sterba
This is the trivial pattern for path auto free, initialize at the beginning and free at the end with simple goto -> return conversions. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-03-18btrfs: use BTRFS_PATH_AUTO_FREE in clear_free_space_tree()David Sterba
This is the trivial pattern for path auto free, initialize at the beginning and free at the end with simple goto -> return conversions. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-03-18btrfs: use BTRFS_PATH_AUTO_FREE in populate_free_space_tree()David Sterba
This is the trivial pattern for path auto free, initialize at the beginning and free at the end with simple goto -> return conversions. This applies to both path and path2. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13btrfs: free-space-tree: remove unnecessary calls to btrfs_mark_buffer_dirty()Filipe Manana
We have several places explicitly calling btrfs_mark_buffer_dirty() but that is not necessarily since the target leaf came from a path that was obtained for a btree search function that modifies the btree, something ike btrfs_insert_empty_item() or anything else that ends up calling btrfs_search_slot() with a value of 1 for its 'cow' argument. These just make the code more verbose, confusing and add a little extra overhead and well as increase the module's text size, so remove them. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2025-01-13btrfs: handle free space tree rebuild in multiple transactionsQu Wenruo
During free space tree rebuild, we're holding a transaction handle for the whole rebuild process. This can lead to blocked task warning, e.g. btrfs-transaction kthread (which is already created before btrfs_start_pre_rw_mount()) can be waked up to join and commit the current transaction. But the free space tree rebuild process may need to go through thousands block groups, this will block btrfs-transaction kthread for a long time. Fix the problem by calling btrfs_should_end_transaction() after each block group, so that we won't hold the transaction handle too long. And since the free-space-tree rebuild can be split into multiple transactions, we need to consider the safety when the rebuild process is interrupted. Thankfully since we only set the FREE_SPACE_TREE compat_ro flag without FREE_SPACE_TREE_VALID flag, even if the rebuild is interrupted, on the next RW mount, we will still go rebuild the free space tree, by deleting any items we have and re-starting the rebuild from scratch. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: do not BUG_ON() when freeing tree block after errorFilipe Manana
When freeing a tree block, at btrfs_free_tree_block(), if we fail to create a delayed reference we don't deal with the error and just do a BUG_ON(). The error most likely to happen is -ENOMEM, and we have a comment mentioning that only -ENOMEM can happen, but that is not true, because in case qgroups are enabled any error returned from btrfs_qgroup_trace_extent_post() (can be -EUCLEAN or anything returned from btrfs_search_slot() for example) can be propagated back to btrfs_free_tree_block(). So stop doing a BUG_ON() and return the error to the callers and make them abort the transaction to prevent leaking space. Syzbot was triggering this, likely due to memory allocation failure injection. Reported-by: syzbot+a306f914b4d01b3958fe@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/000000000000fcba1e05e998263c@google.com/ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>