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2026-03-12btrfs: fix compat mask in error messages in btrfs_check_features()Mark Harmstone1-3/+3
[ Upstream commit 587bb33b10bda645a1028c1737ad3992b3d7cf61 ] Commit d7f67ac9a928 ("btrfs: relax block-group-tree feature dependency checks") introduced a regression when it comes to handling unsupported incompat or compat_ro flags. Beforehand we only printed the flags that we didn't recognize, afterwards we printed them all, which is less useful. Fix the error handling so it behaves like it used to. Fixes: d7f67ac9a928 ("btrfs: relax block-group-tree feature dependency checks") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: print correct subvol num if active swapfile prevents deletionMark Harmstone1-1/+1
[ Upstream commit 1c7e9111f4e6d6d42bc47759c9af1ef91f03ac2c ] Fix the error message in btrfs_delete_subvolume() if we can't delete a subvolume because it has an active swapfile: we were printing the number of the parent rather than the target. Fixes: 60021bd754c6 ("btrfs: prevent subvol with swapfile from being deleted") Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: fix warning in scrub_verify_one_metadata()Mark Harmstone1-1/+1
[ Upstream commit 44e2fda66427a0442d8d2c0e6443256fb458ab6b ] Commit b471965fdb2d ("btrfs: fix replace/scrub failure with metadata_uuid") fixed the comparison in scrub_verify_one_metadata() to use metadata_uuid rather than fsid, but left the warning as it was. Fix it so it matches what we're doing. Fixes: b471965fdb2d ("btrfs: fix replace/scrub failure with metadata_uuid") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: fix objectid value in error message in check_extent_data_ref()Mark Harmstone1-1/+1
[ Upstream commit a10172780526c2002e062102ad4f2aabac495889 ] Fix a copy-paste error in check_extent_data_ref(): we're printing root as in the message above, we should be printing objectid. Fixes: f333a3c7e832 ("btrfs: tree-checker: validate dref root and objectid") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: fix incorrect key offset in error message in check_dev_extent_item()Mark Harmstone1-1/+1
[ Upstream commit 511dc8912ae3e929c1a182f5e6b2326516fd42a0 ] Fix the error message in check_dev_extent_item(), when an overlapping stripe is encountered. For dev extents, objectid is the disk number and offset the physical address, so prev_key->objectid should actually be prev_key->offset. (I can't take any credit for this one - this was discovered by Chris and his friend Claude.) Reported-by: Chris Mason <clm@fb.com> Fixes: 008e2512dc56 ("btrfs: tree-checker: add dev extent item checks") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: fix error message order of parameters in btrfs_delete_delayed_dir_index()Mark Harmstone1-1/+1
[ Upstream commit 3cf0f35779d364cf2003c617bb7f3f3e41023372 ] Fix the error message in btrfs_delete_delayed_dir_index() if __btrfs_add_delayed_item() fails: the message says root, inode, index, error, but we're actually passing index, root, inode, error. Fixes: adc1ef55dc04 ("btrfs: add details to error messages at btrfs_delete_delayed_dir_index()") Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: Filipe Manana <fdmanana@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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-12btrfs: free pages on error in btrfs_uring_read_extent()Miquel Sabaté Solà1-1/+6
[ Upstream commit 3f501412f2079ca14bf68a18d80a2b7a823f1f64 ] In this function the 'pages' object is never freed in the hopes that it is picked up by btrfs_uring_read_finished() whenever that executes in the future. But that's just the happy path. Along the way previous allocations might have gone wrong, or we might not get -EIOCBQUEUED from btrfs_encoded_read_regular_fill_pages(). In all these cases, we go to a cleanup section that frees all memory allocated by this function without assuming any deferred execution, and this also needs to happen for the 'pages' allocation. Fixes: 34310c442e17 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)") Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com> Reviewed-by: Filipe Manana <fdmanana@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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: continue trimming remaining devices on failurejinbaohong1-1/+1
[ Upstream commit 912d1c6680bdb40b72b1b9204706f32b6eb842c3 ] Commit 93bba24d4b5a ("btrfs: Enhance btrfs_trim_fs function to handle error better") intended to make device trimming continue even if one device fails, tracking failures and reporting them at the end. However, it used 'break' instead of 'continue', causing the loop to exit on the first device failure. Fix this by replacing 'break' with 'continue'. Fixes: 93bba24d4b5a ("btrfs: Enhance btrfs_trim_fs function to handle error better") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Robbie Ko <robbieko@synology.com> Signed-off-by: jinbaohong <jinbaohong@synology.com> Reviewed-by: Filipe Manana <fdmanana@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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: zoned: fixup last alloc pointer after extent removal for RAID0/10Naohiro Aota1-15/+179
[ Upstream commit 52ee9965d09b2c56a027613db30d1fb20d623861 ] When a block group is composed of a sequential write zone and a conventional zone, we recover the (pseudo) write pointer of the conventional zone using the end of the last allocated position. However, if the last extent in a block group is removed, the last extent position will be smaller than the other real write pointer position. Then, that will cause an error due to mismatch of the write pointers. We can fixup this case by moving the alloc_offset to the corresponding write pointer position. Fixes: 568220fa9657 ("btrfs: zoned: support RAID0/1/10 on top of raid stripe tree") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: zoned: fixup last alloc pointer after extent removal for DUPNaohiro Aota1-0/+14
[ Upstream commit e2d848649e64de39fc1b9c64002629b4daa1105d ] When a block group is composed of a sequential write zone and a conventional zone, we recover the (pseudo) write pointer of the conventional zone using the end of the last allocated position. However, if the last extent in a block group is removed, the last extent position will be smaller than the other real write pointer position. Then, that will cause an error due to mismatch of the write pointers. We can fixup this case by moving the alloc_offset to the corresponding write pointer position. Fixes: c0d90a79e8e6 ("btrfs: zoned: fix alloc_offset calculation for partly conventional block groups") CC: stable@vger.kernel.org # 6.16+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: zoned: fixup last alloc pointer after extent removal for RAID1Naohiro Aota1-0/+15
[ Upstream commit dda3ec9ee6b3e120603bff1b798f25b51e54ac5d ] When a block group is composed of a sequential write zone and a conventional zone, we recover the (pseudo) write pointer of the conventional zone using the end of the last allocated position. However, if the last extent in a block group is removed, the last extent position will be smaller than the other real write pointer position. Then, that will cause an error due to mismatch of the write pointers. We can fixup this case by moving the alloc_offset to the corresponding write pointer position. Fixes: 568220fa9657 ("btrfs: zoned: support RAID0/1/10 on top of raid stripe tree") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: fix periodic reclaim conditionSun YangKai2-11/+16
[ Upstream commit 19eff93dc738e8afaa59cb374b44bb5a162e6c2d ] Problems with current implementation: 1. reclaimable_bytes is signed while chunk_sz is unsigned, causing negative reclaimable_bytes to trigger reclaim unexpectedly 2. The "space must be freed between scans" assumption breaks the two-scan requirement: first scan marks block groups, second scan reclaims them. Without the second scan, no reclamation occurs. Instead, track actual reclaim progress: pause reclaim when block groups will be reclaimed, and resume only when progress is made. This ensures reclaim continues until no further progress can be made. And resume periodic reclaim when there's enough free space. And we take care if reclaim is making any progress now, so it's unnecessary to set periodic_reclaim_ready to false when failed to reclaim a block group. Fixes: 813d4c6422516 ("btrfs: prevent pathological periodic reclaim loops") CC: stable@vger.kernel.org # 6.12+ Suggested-by: Boris Burkov <boris@bur.io> Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Sun YangKai <sunk67188@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: do not ASSERT() when the fs flips RO inside btrfs_repair_io_failure()Qu Wenruo1-1/+7
[ Upstream commit 8ceaad6cd6e7fa5f73b0b2796a2e85d75d37e9f3 ] [BUG] There is a bug report that when btrfs hits ENOSPC error in a critical path, btrfs flips RO (this part is expected, although the ENOSPC bug still needs to be addressed). The problem is after the RO flip, if there is a read repair pending, we can hit the ASSERT() inside btrfs_repair_io_failure() like the following: BTRFS info (device vdc): relocating block group 30408704 flags metadata|raid1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -28) WARNING: fs/btrfs/extent-tree.c:3235 at __btrfs_free_extent.isra.0+0x453/0xfd0, CPU#1: btrfs/383844 Modules linked in: kvm_intel kvm irqbypass [...] ---[ end trace 0000000000000000 ]--- BTRFS info (device vdc state EA): 2 enospc errors during balance BTRFS info (device vdc state EA): balance: ended with status: -30 BTRFS error (device vdc state EA): parent transid verify failed on logical 30556160 mirror 2 wanted 8 found 6 BTRFS error (device vdc state EA): bdev /dev/nvme0n1 errs: wr 0, rd 0, flush 0, corrupt 10, gen 0 [...] assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 ------------[ cut here ]------------ assertion failed: !(fs_info->sb->s_flags & SB_RDONLY) :: 0, in fs/btrfs/bio.c:938 kernel BUG at fs/btrfs/bio.c:938! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 868 Comm: kworker/u8:13 Tainted: G W N 6.19.0-rc6+ #4788 PREEMPT(full) Tainted: [W]=WARN, [N]=TEST Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Workqueue: btrfs-endio simple_end_io_work RIP: 0010:btrfs_repair_io_failure.cold+0xb2/0x120 RSP: 0000:ffffc90001d2bcf0 EFLAGS: 00010246 RAX: 0000000000000051 RBX: 0000000000001000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8305cf42 RDI: 00000000ffffffff RBP: 0000000000000002 R08: 00000000fffeffff R09: ffffffff837fa988 R10: ffffffff8327a9e0 R11: 6f69747265737361 R12: ffff88813018d310 R13: ffff888168b8a000 R14: ffffc90001d2bd90 R15: ffff88810a169000 FS: 0000000000000000(0000) GS:ffff8885e752c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 ------------[ cut here ]------------ [CAUSE] The cause of -ENOSPC error during the test case btrfs/124 is still unknown, although it's known that we still have cases where metadata can be over-committed but can not be fulfilled correctly, thus if we hit such ENOSPC error inside a critical path, we have no choice but abort the current transaction. This will mark the fs read-only. The problem is inside the btrfs_repair_io_failure() path that we require the fs not to be mount read-only. This is normally fine, but if we are doing a read-repair meanwhile the fs flips RO due to a critical error, we can enter btrfs_repair_io_failure() with super block set to read-only, thus triggering the above crash. [FIX] Just replace the ASSERT() with a proper return if the fs is already read-only. Reported-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-btrfs/20260126045555.GB31641@lst.de/ Tested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: replace BUG() with error handling in __btrfs_balance()Adarsh Das1-2/+8
[ Upstream commit be6324a809dbda76d5fdb23720ad9b20e5c1905c ] We search with offset (u64)-1 which should never match exactly. Previously this was handled with BUG(). Now logs an error and return -EUCLEAN. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Adarsh Das <adarshdas950@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: handle user interrupt properly in btrfs_trim_fs()jinbaohong1-0/+11
[ Upstream commit bfb670b9183b0e4ba660aff2e396ec1cc01d0761 ] When a fatal signal is pending or the process is freezing, btrfs_trim_block_group() and btrfs_trim_free_extents() return -ERESTARTSYS. Currently this is treated as a regular error: the loops continue to the next iteration and count it as a block group or device failure. Instead, break out of the loops immediately and return -ERESTARTSYS to userspace without counting it as a failure. Also skip the device loop entirely if the block group loop was interrupted. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Robbie Ko <robbieko@synology.com> Signed-off-by: jinbaohong <jinbaohong@synology.com> Reviewed-by: Filipe Manana <fdmanana@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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: fallback to buffered IO if the data profile has duplicationQu Wenruo1-0/+12
[ Upstream commit 7c2830f00c3e086292c1ee9f27b61efaf8e76c9a ] [BACKGROUND] Inspired by a recent kernel bug report, which is related to direct IO buffer modification during writeback, that leads to contents mismatch of different RAID1 mirrors. [CAUSE AND PROBLEMS] The root cause is exactly the same explained in commit 968f19c5b1b7 ("btrfs: always fallback to buffered write if the inode requires checksum"), that we can not trust direct IO buffer which can be modified halfway during writeback. Unlike data checksum verification, if this happened on inodes without data checksum but has the data has extra mirrors, it will lead to stealth data mismatch on different mirrors. This will be way harder to detect without data checksum. Furthermore for RAID56, we can even have data without checksum and data with checksum mixed inside the same full stripe. In that case if the direct IO buffer got changed halfway for the nodatasum part, the data with checksum immediately lost its ability to recover, e.g.: " " = Good old data or parity calculated using good old data "X" = Data modified during writeback 0 32K 64K Data 1 | | Has csum Data 2 |XXXXXXXXXXXXXXXX | No csum Parity | | In above case, the parity is calculated using data 1 (has csum, from page cache, won't change during writeback), and old data 2 (has no csum, direct IO write). After parity is calculated, but before submission to the storage, direct IO buffer of data 2 is modified, causing the range [0, 32K) of data 2 has a different content. Now all data is submitted to the storage, and the fs got fully synced. Then the device of data 1 is lost, has to be rebuilt from data 2 and parity. But since the data 2 has some modified data, and the parity is calculated using old data, the recovered data is no the same for data 1, causing data checksum mismatch. [FIX] Fix the problem by checking the data allocation profile. If our data allocation profile is either RAID0 or SINGLE, we can allow true zero-copy direct IO and the end user is fully responsible for any race. However this is not going to fix all situations, as it's still possible to race with balance where the fs got a new data profile after the data allocation profile check. But this fix should still greatly reduce the window of the original bug. Link: https://bugzilla.kernel.org/show_bug.cgi?id=99171 Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04btrfs: don't BUG() on unexpected delayed ref type in run_one_delayed_ref()Filipe Manana1-8/+12
[ Upstream commit c7d1d4ff56744074e005771aff193b927392d51f ] There is no need to BUG(), we can just return an error and log an error message. Reviewed-by: Boris Burkov <boris@bur.io> 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not foundFilipe Manana1-4/+7
[ Upstream commit ecb7c2484cfc83a93658907580035a8adf1e0a92 ] If btrfs_search_slot_for_read() returns 1, it means we did not find any key greater than or equals to the key we asked for, meaning we have reached the end of the tree and therefore the path is not valid. If this happens we need to break out of the loop and stop, instead of continuing and accessing an invalid path. Fixes: 5223cc60b40a ("btrfs: drop the path before adding qgroup items when enabling qgroups") 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: use the correct type to initialize block reserve for delayed refsFilipe Manana2-4/+5
[ Upstream commit 2155d0c0a761a56ce7ede83a26eb23ea0f935260 ] When initializing the delayed refs block reserve for a transaction handle we are passing a type of BTRFS_BLOCK_RSV_DELOPS, which is meant for delayed items and not for delayed refs. The correct type for delayed refs is BTRFS_BLOCK_RSV_DELREFS. On release of any excess space reserved in a local delayed refs reserve, we also should transfer that excess space to the global block reserve (it it's full, we return to the space info for general availability). By initializing a transaction's local delayed refs block reserve with a type of BTRFS_BLOCK_RSV_DELOPS, we were also causing any excess space released from the delayed block reserve (fs_info->delayed_block_rsv, used for delayed inodes and items) to be transferred to the global block reserve instead of the global delayed refs block reserve. This was an unintentional change in commit 28270e25c69a ("btrfs: always reserve space for delayed refs when starting transaction"), but it's not particularly serious as things tend to cancel out each other most of the time and it's relatively rare to be anywhere near exhaustion of the global reserve. Fix this by initializing a transaction's local delayed refs reserve with a type of BTRFS_BLOCK_RSV_DELREFS and making btrfs_block_rsv_release() attempt to transfer unused space from such a reserve into the global block reserve, just as we did before that commit for when the block reserve is a delayed refs rsv. Reported-by: Alex Lyakas <alex.lyakas@zadara.com> Link: https://lore.kernel.org/linux-btrfs/CAOcd+r0FHG5LWzTSu=LknwSoqxfw+C00gFAW7fuX71+Z5AfEew@mail.gmail.com/ Fixes: 28270e25c69a ("btrfs: always reserve space for delayed refs when starting transaction") Reviewed-by: Alex Lyakas <alex.lyakas@zadara.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: reset block group size class when it becomes emptyJiasheng Jiang1-0/+10
[ Upstream commit 5870ec7c8fe57a8b2c65005e5da5efc054faa3e6 ] Block group size classes are managed consistently everywhere. Currently, btrfs_use_block_group_size_class() sets a block group's size class to specialize it for a specific allocation size. However, this size class remains "stale" even if the block group becomes completely empty (both used and reserved bytes reach zero). This happens in two scenarios: 1. When space reservations are freed (e.g., due to errors or transaction aborts) via btrfs_free_reserved_bytes(). 2. When the last extent in a block group is freed via btrfs_update_block_group(). While size classes are advisory, a stale size class can cause find_free_extent to unnecessarily skip candidate block groups during initial search loops. This undermines the purpose of size classes to reduce fragmentation by keeping block groups restricted to a specific size class when they could be reused for any size. Fix this by resetting the size class to BTRFS_BG_SZ_NONE whenever a block group's used and reserved counts both reach zero. This ensures that empty block groups are fully available for any allocation size in the next cycle. Fixes: 52bb7a2166af ("btrfs: introduce size class to block group allocator") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: fix EEXIST abort due to non-consecutive gaps in chunk allocationBoris Burkov1-60/+183
[ Upstream commit b14c5e04bd0f722ed631845599d52d03fcae1bc1 ] I have been observing a number of systems aborting at insert_dev_extents() in btrfs_create_pending_block_groups(). The following is a sample stack trace of such an abort coming from forced chunk allocation (typically behind CONFIG_BTRFS_EXPERIMENTAL) but this can theoretically happen to any DUP chunk allocation. [81.801] ------------[ cut here ]------------ [81.801] BTRFS: Transaction aborted (error -17) [81.801] WARNING: fs/btrfs/block-group.c:2876 at btrfs_create_pending_block_groups+0x721/0x770 [btrfs], CPU#1: bash/319 [81.802] Modules linked in: virtio_net btrfs xor zstd_compress raid6_pq null_blk [81.803] CPU: 1 UID: 0 PID: 319 Comm: bash Kdump: loaded Not tainted 6.19.0-rc6+ #319 NONE [81.803] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014 [81.804] RIP: 0010:btrfs_create_pending_block_groups+0x723/0x770 [btrfs] [81.806] RSP: 0018:ffffa36241a6bce8 EFLAGS: 00010282 [81.806] RAX: 000000000000000d RBX: ffff8e699921e400 RCX: 0000000000000000 [81.807] RDX: 0000000002040001 RSI: 00000000ffffffef RDI: ffffffffc0608bf0 [81.807] RBP: 00000000ffffffef R08: ffff8e69830f6000 R09: 0000000000000007 [81.808] R10: ffff8e699921e5e8 R11: 0000000000000000 R12: ffff8e6999228000 [81.808] R13: ffff8e6984d82000 R14: ffff8e69966a69c0 R15: ffff8e69aa47b000 [81.809] FS: 00007fec6bdd9740(0000) GS:ffff8e6b1b379000(0000) knlGS:0000000000000000 [81.809] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [81.810] CR2: 00005604833670f0 CR3: 0000000116679000 CR4: 00000000000006f0 [81.810] Call Trace: [81.810] <TASK> [81.810] __btrfs_end_transaction+0x3e/0x2b0 [btrfs] [81.811] btrfs_force_chunk_alloc_store+0xcd/0x140 [btrfs] [81.811] kernfs_fop_write_iter+0x15f/0x240 [81.812] vfs_write+0x264/0x500 [81.812] ksys_write+0x6c/0xe0 [81.812] do_syscall_64+0x66/0x770 [81.812] entry_SYSCALL_64_after_hwframe+0x76/0x7e [81.813] RIP: 0033:0x7fec6be66197 [81.814] RSP: 002b:00007fffb159dd30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 [81.815] RAX: ffffffffffffffda RBX: 00007fec6bdd9740 RCX: 00007fec6be66197 [81.815] RDX: 0000000000000002 RSI: 0000560483374f80 RDI: 0000000000000001 [81.816] RBP: 0000560483374f80 R08: 0000000000000000 R09: 0000000000000000 [81.816] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002 [81.817] R13: 00007fec6bfb85c0 R14: 00007fec6bfb5ee0 R15: 00005604833729c0 [81.817] </TASK> [81.817] irq event stamp: 20039 [81.818] hardirqs last enabled at (20047): [<ffffffff99a68302>] __up_console_sem+0x52/0x60 [81.818] hardirqs last disabled at (20056): [<ffffffff99a682e7>] __up_console_sem+0x37/0x60 [81.819] softirqs last enabled at (19470): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0 [81.819] softirqs last disabled at (19463): [<ffffffff999d2b46>] __irq_exit_rcu+0x96/0xc0 [81.820] ---[ end trace 0000000000000000 ]--- [81.820] BTRFS: error (device dm-7 state A) in btrfs_create_pending_block_groups:2876: errno=-17 Object already exists Inspecting these aborts with drgn, I observed a pattern of overlapping chunk_maps. Note how stripe 1 of the first chunk overlaps in physical address with stripe 0 of the second chunk. Physical Start Physical End Length Logical Type Stripe ---------------------------------------------------------------------------------------------------- 0x0000000102500000 0x0000000142500000 1.0G 0x0000000641d00000 META|DUP 0/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000641d00000 META|DUP 1/2 0x0000000142500000 0x0000000182500000 1.0G 0x0000000601d00000 META|DUP 0/2 0x0000000182500000 0x00000001c2500000 1.0G 0x0000000601d00000 META|DUP 1/2 Now how could this possibly happen? All chunk allocation is protected by the chunk_mutex so racing allocations should see a consistent view of the CHUNK_ALLOCATED bit in the chunk allocation extent-io-tree (device->alloc_state as set by chunk_map_device_set_bits()) The tree itself is protected by a spin lock, and clearing/setting the bits is always protected by fs_info->mapping_tree_lock, so no race is apparent. It turns out that there is a subtle bug in the logic regarding chunk allocations that have happened in the current transaction, known as "pending extents". The chunk allocation as defined in find_free_dev_extent() is a loop which searches the commit root of the dev_root and looks for gaps between DEV_EXTENT items. For those gaps, it then checks alloc_state bitmap for any pending extents and adjusts the hole that it finds accordingly. However, the logic in that adjustment assumes that the first pending extent is the only one in that range. e.g., given a layout with two non-consecutive pending extents in a hole passed to dev_extent_hole_check() via *hole_start and *hole_size: |----pending A----| real hole |----pending B----| | candidate hole | *hole_start *hole_start + *hole_size the code incorrectly returns a "hole" from the end of pending extent A until the passed in hole end, failing to account for pending B. However, it is not entirely obvious that it is actually possible to produce such a layout. I was able to reproduce it, but with some contortions: I continued to use the force chunk allocation sysfs file and I introduced a long delay (10 seconds) into the start of the cleaner thread. I also prevented the unused bgs cleaning logic from ever deleting metadata bgs. These help make it easier to deterministically produce the condition but shouldn't really matter if you imagine the conditions happening by race/luck. Allocations/frees can happen concurrently with the cleaner thread preparing to process an unused extent and both create some used chunks with an unused chunk interleaved, all during one transaction. Then btrfs_delete_unused_bgs() sees the unused one and clears it, leaving a range with several pending chunk allocations and a gap in the middle. The basic idea is that the unused_bgs cleanup work happens on a worker so if we allocate 3 block groups in one transaction, then the cleaner work kicked off by the previous transaction comes through and deletes the middle one of the 3, then the commit root shows no dev extents and we have the bad pattern in the extent-io-tree. One final consideration is that the code happens to loop to the next hole if there are no more extents at all, so we need one more dev extent way past the area we are working in. Something like the following demonstrates the technique: # push the BG frontier out to 20G fallocate -l 20G $mnt/foo # allocate one more that will prevent the "no more dev extents" luck fallocate -l 1G $mnt/sticky # sync sync # clear out the allocation area rm $mnt/foo sync _cleaner # let everything quiesce sleep 20 sync # dev tree should have one bg 20G out and the rest at the beginning.. # sort of like an empty FS but with a random sticky chunk. # kick off the cleaner in the background, remember it will sleep 10s # before doing interesting work _cleaner & sleep 3 # create 3 trivial block groups, all empty, all immediately marked as unused. echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc" echo 1 > "$(_btrfs_sysfs_space_info $dev data)/force_chunk_alloc" echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc" # let the cleaner thread definitely finish, it will remove the data bg sleep 10 # this allocation sees the non-consecutive pending metadata chunks with # data chunk gap of 1G and allocates a 2G extent in that hole. ENOSPC! echo 1 > "$(_btrfs_sysfs_space_info $dev metadata)/force_chunk_alloc" As for the fix, it is not that obvious. I could not see a trivial way to do it even by adding backup loops into find_free_dev_extent(), so I opted to change the semantics of dev_extent_hole_check() to not stop looping until it finds a sufficiently big hole. For clarity, this also required changing the helper function contains_pending_extent() into two new helpers which find the first pending extent and the first suitable hole in a range. I attempted to clean up the documentation and range calculations to be as consistent and clear as possible for the future. I also looked at the zoned case and concluded that the loop there is different and not to be unified with this one. As far as I can tell, the zoned check will only further constrain the hole so looping back to find more holes is acceptable. Though given that zoned really only appends, I find it highly unlikely that it is susceptible to this bug. Fixes: 1b9845081633 ("Btrfs: fix find_free_dev_extent() malfunction in case device tree has hole") Reported-by: Dimitrios Apostolou <jimis@gmx.net> Closes: https://lore.kernel.org/linux-btrfs/q7760374-q1p4-029o-5149-26p28421s468@tzk.arg/ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: fix block_group_tree dirty_list corruptionBoris Burkov1-7/+0
[ Upstream commit 3a1f4264daed4b419c325a7fe35e756cada3cf82 ] When the incompat flag EXTENT_TREE_V2 is set, we unconditionally add the block group tree to the switch_commits list before calling switch_commit_roots, as we do for the tree root and the chunk root. However, the block group tree uses normal root dirty tracking and in any transaction that does an allocation and dirties a block group, the block group root will already be linked to a list by the dirty_list field and this use of list_add_tail() is invalid and corrupts the prev/next members of block_group_root->dirty_list. This is apparent on a subsequent list_del on the prev if we enable CONFIG_DEBUG_LIST: [32.1571] ------------[ cut here ]------------ [32.1572] list_del corruption. next->prev should beffff958890202538, but was ffff9588992bd538. (next=ffff958890201538) [32.1575] WARNING: lib/list_debug.c:65 at 0x0, CPU#3: sync/607 [32.1583] CPU: 3 UID: 0 PID: 607 Comm: sync Not tainted 6.18.0 #24PREEMPT(none) [32.1585] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS1.17.0-4.fc41 04/01/2014 [32.1587] RIP: 0010:__list_del_entry_valid_or_report+0x108/0x120 [32.1593] RSP: 0018:ffffaa288287fdd0 EFLAGS: 00010202 [32.1594] RAX: 0000000000000001 RBX: ffff95889326e800 RCX:ffff958890201538 [32.1596] RDX: ffff9588992bd538 RSI: ffff958890202538 RDI:ffffffff82a41e00 [32.1597] RBP: ffff958890202538 R08: ffffffff828fc1e8 R09:00000000ffffefff [32.1599] R10: ffffffff8288c200 R11: ffffffff828e4200 R12:ffff958890201538 [32.1601] R13: ffff95889326e958 R14: ffff958895c24000 R15:ffff958890202538 [32.1603] FS: 00007f0c28eb5740(0000) GS:ffff958af2bd2000(0000)knlGS:0000000000000000 [32.1605] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [32.1607] CR2: 00007f0c28e8a3cc CR3: 0000000109942005 CR4:0000000000370ef0 [32.1609] Call Trace: [32.1610] <TASK> [32.1611] switch_commit_roots+0x82/0x1d0 [btrfs] [32.1615] btrfs_commit_transaction+0x968/0x1550 [btrfs] [32.1618] ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs] [32.1621] __iterate_supers+0xe8/0x190 [32.1622] ? __pfx_sync_fs_one_sb+0x10/0x10 [32.1623] ksys_sync+0x63/0xb0 [32.1624] __do_sys_sync+0xe/0x20 [32.1625] do_syscall_64+0x73/0x450 [32.1626] entry_SYSCALL_64_after_hwframe+0x76/0x7e [32.1627] RIP: 0033:0x7f0c28d05d2b [32.1632] RSP: 002b:00007ffc9d988048 EFLAGS: 00000246 ORIG_RAX:00000000000000a2 [32.1634] RAX: ffffffffffffffda RBX: 00007ffc9d988228 RCX:00007f0c28d05d2b [32.1636] RDX: 00007f0c28e02301 RSI: 00007ffc9d989b21 RDI:00007f0c28dba90d [32.1637] RBP: 0000000000000001 R08: 0000000000000001 R09:0000000000000000 [32.1639] R10: 0000000000000000 R11: 0000000000000246 R12:000055b96572cb80 [32.1641] R13: 000055b96572b19f R14: 00007f0c28dfa434 R15:000055b96572b034 [32.1643] </TASK> [32.1644] irq event stamp: 0 [32.1644] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [32.1646] hardirqs last disabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260 [32.1648] softirqs last enabled at (0): [<ffffffff81298817>]copy_process+0xb37/0x2260 [32.1650] softirqs last disabled at (0): [<0000000000000000>] 0x0 [32.1652] ---[ end trace 0000000000000000 ]--- Furthermore, this list corruption eventually (when we happen to add a new block group) results in getting the switch_commits and dirty_cowonly_roots lists mixed up and attempting to call update_root on the tree root which can't be found in the tree root, resulting in a transaction abort: [87.8269] BTRFS critical (device nvme1n1): unable to find root key (1 0 0) in tree 1 [87.8272] ------------[ cut here ]------------ [87.8274] BTRFS: Transaction aborted (error -117) [87.8275] WARNING: fs/btrfs/root-tree.c:153 at 0x0, CPU#4: sync/703 [87.8285] CPU: 4 UID: 0 PID: 703 Comm: sync Not tainted 6.18.0 #25 PREEMPT(none) [87.8287] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-4.fc41 04/01/2014 [87.8289] RIP: 0010:btrfs_update_root+0x296/0x790 [btrfs] [87.8295] RSP: 0018:ffffa58d035dfd60 EFLAGS: 00010282 [87.8297] RAX: ffff9a59126ddb68 RBX: ffff9a59126dc000 RCX: 0000000000000000 [87.8299] RDX: 0000000000000000 RSI: 00000000ffffff8b RDI: ffffffffc0b28270 [87.8301] RBP: ffff9a5904aec000 R08: 0000000000000000 R09: 00000000ffffefff [87.8303] R10: ffffffff9ac8c200 R11: ffffffff9ace4200 R12: 0000000000000001 [87.8305] R13: ffff9a59041740e8 R14: ffff9a5904aec1f7 R15: ffff9a590fdefaf0 [87.8307] FS: 00007f54cde6b740(0000) GS:ffff9a5b5a81c000(0000) knlGS:0000000000000000 [87.8309] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [87.8310] CR2: 00007f54cde403cc CR3: 0000000112902004 CR4: 0000000000370ef0 [87.8312] Call Trace: [87.8313] <TASK> [87.8314] ? _raw_spin_unlock+0x23/0x40 [87.8315] commit_cowonly_roots+0x1ad/0x250 [btrfs] [87.8317] ? btrfs_commit_transaction+0x79b/0x1560 [btrfs] [87.8320] btrfs_commit_transaction+0x8aa/0x1560 [btrfs] [87.8322] ? btrfs_attach_transaction_barrier+0x23/0x60 [btrfs] [87.8325] __iterate_supers+0xf1/0x170 [87.8326] ? __pfx_sync_fs_one_sb+0x10/0x10 [87.8327] ksys_sync+0x63/0xb0 [87.8328] __do_sys_sync+0xe/0x20 [87.8329] do_syscall_64+0x73/0x450 [87.8330] entry_SYSCALL_64_after_hwframe+0x76/0x7e [87.8331] RIP: 0033:0x7f54cdd05d2b [87.8336] RSP: 002b:00007fff1b58ff78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 [87.8338] RAX: ffffffffffffffda RBX: 00007fff1b590158 RCX: 00007f54cdd05d2b [87.8340] RDX: 00007f54cde02301 RSI: 00007fff1b592b66 RDI: 00007f54cddba90d [87.8342] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 [87.8344] R10: 0000000000000000 R11: 0000000000000246 R12: 000055e07ca96b80 [87.8346] R13: 000055e07ca9519f R14: 00007f54cddfa434 R15: 000055e07ca95034 [87.8348] </TASK> [87.8348] irq event stamp: 0 [87.8349] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [87.8351] hardirqs last disabled at (0): [<ffffffff99698797>] copy_process+0xb37/0x21e0 [87.8353] softirqs last enabled at (0): [<ffffffff99698797>] copy_process+0xb37/0x21e0 [87.8355] softirqs last disabled at (0): [<0000000000000000>] 0x0 [87.8357] ---[ end trace 0000000000000000 ]--- [87.8358] BTRFS: error (device nvme1n1 state A) in btrfs_update_root:153: errno=-117 Filesystem corrupted [87.8360] BTRFS info (device nvme1n1 state EA): forced readonly [87.8362] BTRFS warning (device nvme1n1 state EA): Skipping commit of aborted transaction. [87.8364] BTRFS: error (device nvme1n1 state EA) in cleanup_transaction:2037: errno=-117 Filesystem corrupted Since the block group tree was pulled out of the extent tree and uses normal root dirty tracking, remove the offending extra list_add. This fixes the list corruption and the resulting fs corruption. Fixes: 14033b08a029 ("btrfs: don't save block group root into super block") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: qgroup: return correct error when deleting qgroup relation itemFilipe Manana1-1/+3
[ Upstream commit 51b1fcf71c88c3c89e7dcf07869c5de837b1f428 ] If we fail to delete the second qgroup relation item, we end up returning success or -ENOENT in case the first item does not exist, instead of returning the error from the second item deletion. Fixes: 73798c465b66 ("btrfs: qgroup: Try our best to delete qgroup relations") 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-27btrfs: zoned: don't zone append to conventional zoneJohannes Thumshirn2-10/+12
[ Upstream commit b39b26e017c7889181cb84032e22bef72e81cf29 ] In case of a zoned RAID, it can happen that a data write is targeting a sequential write required zone and a conventional zone. In this case the bio will be marked as REQ_OP_ZONE_APPEND but for the conventional zone, this needs to be REQ_OP_WRITE. The setting of REQ_OP_ZONE_APPEND is deferred to the last possible time in btrfs_submit_dev_bio(), but the decision if we can use zone append is cached in btrfs_bio. CC: Naohiro Aota <naohiro.aota@wdc.com> Fixes: e9b9b911e03c ("btrfs: add raid stripe tree to features enabled with debug config") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-03Merge tag 'for-6.19-rc8-tag' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fix from David Sterba: "A regression fix for a memory leak when raid56 is used" * tag 'for-6.19-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: raid56: fix memory leak of btrfs_raid_bio::stripe_uptodate_bitmap
2026-02-03btrfs: raid56: fix memory leak of btrfs_raid_bio::stripe_uptodate_bitmapFilipe Manana1-0/+1
We allocate the bitmap but we never free it in free_raid_bio_pointers(). Fix this by adding a bitmap_free() call against the stripe_uptodate_bitmap of a raid bio. Fixes: 1810350b04ef ("btrfs: raid56: move sector_ptr::uptodate into a dedicated bitmap") Reported-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-btrfs/20260126045315.GA31641@lst.de/ Reviewed-by: Qu Wenruo <wqu@suse.com> Tested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-29Merge tag 'for-6.19-rc7-tag' of ↵Linus Torvalds4-26/+3
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - fix leaked folio refcount on s390x when using hw zlib compression acceleration - remove own threshold from ->writepages() which could collide with cgroup limits and lead to a deadlock when metadadata are not written because the amount is under the internal limit * tag 'for-6.19-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: zlib: fix the folio leak on S390 hardware acceleration btrfs: do not strictly require dirty metadata threshold for metadata writepages
2026-01-21btrfs: zlib: fix the folio leak on S390 hardware accelerationQu Wenruo1-0/+1
[BUG] After commit aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration buffer preparation"), we no longer release the folio of the page cache of folio returned by btrfs_compress_filemap_get_folio() for S390 hardware acceleration path. [CAUSE] Before that commit, we call kumap_local() and folio_put() after handling each folio. Although the timing is not ideal (it release previous folio at the beginning of the loop, and rely on some extra cleanup out of the loop), it at least handles the folio release correctly. Meanwhile the refactored code is easier to read, it lacks the call to release the filemap folio. [FIX] Add the missing folio_put() for copy_data_into_buffer(). CC: linux-s390@vger.kernel.org # 6.18+ Fixes: aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration buffer preparation") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-21btrfs: do not strictly require dirty metadata threshold for metadata writepagesQu Wenruo3-26/+2
[BUG] There is an internal report that over 1000 processes are waiting at the io_schedule_timeout() of balance_dirty_pages(), causing a system hang and trigger a kernel coredump. The kernel is v6.4 kernel based, but the root problem still applies to any upstream kernel before v6.18. [CAUSE] From Jan Kara for his wisdom on the dirty page balance behavior first. This cgroup dirty limit was what was actually playing the role here because the cgroup had only a small amount of memory and so the dirty limit for it was something like 16MB. Dirty throttling is responsible for enforcing that nobody can dirty (significantly) more dirty memory than there's dirty limit. Thus when a task is dirtying pages it periodically enters into balance_dirty_pages() and we let it sleep there to slow down the dirtying. When the system is over dirty limit already (either globally or within a cgroup of the running task), we will not let the task exit from balance_dirty_pages() until the number of dirty pages drops below the limit. So in this particular case, as I already mentioned, there was a cgroup with relatively small amount of memory and as a result with dirty limit set at 16MB. A task from that cgroup has dirtied about 28MB worth of pages in btrfs btree inode and these were practically the only dirty pages in that cgroup. So that means the only way to reduce the dirty pages of that cgroup is to writeback the dirty pages of btrfs btree inode, and only after that those processes can exit balance_dirty_pages(). Now back to the btrfs part, btree_writepages() is responsible for writing back dirty btree inode pages. The problem here is, there is a btrfs internal threshold that if the btree inode's dirty bytes are below the 32M threshold, it will not do any writeback. This behavior is to batch as much metadata as possible so we won't write back those tree blocks and then later re-COW them again for another modification. This internal 32MiB is higher than the existing dirty page size (28MiB), meaning no writeback will happen, causing a deadlock between btrfs and cgroup: - Btrfs doesn't want to write back btree inode until more dirty pages - Cgroup/MM doesn't want more dirty pages for btrfs btree inode Thus any process touching that btree inode is put into sleep until the number of dirty pages is reduced. Thanks Jan Kara a lot for the analysis of the root cause. [ENHANCEMENT] Since kernel commit b55102826d7d ("btrfs: set AS_KERNEL_FILE on the btree_inode"), btrfs btree inode pages will only be charged to the root cgroup which should have a much larger limit than btrfs' 32MiB threshold. So it should not affect newer kernels. But for all current LTS kernels, they are all affected by this problem, and backporting the whole AS_KERNEL_FILE may not be a good idea. Even for newer kernels I still think it's a good idea to get rid of the internal threshold at btree_writepages(), since for most cases cgroup/MM has a better view of full system memory usage than btrfs' fixed threshold. For internal callers using btrfs_btree_balance_dirty() since that function is already doing internal threshold check, we don't need to bother them. But for external callers of btree_writepages(), just respect their requests and write back whatever they want, ignoring the internal btrfs threshold to avoid such deadlock on btree inode dirty page balancing. CC: stable@vger.kernel.org CC: Jan Kara <jack@suse.cz> Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-21Merge tag 'for-6.19-rc6-tag' of ↵Linus Torvalds5-2/+73
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - protect reading super block vs setting block size externally (found by syzbot) - make sure no transaction is started in read-only mode even with some rescue mount option combinations - fix checksum calculation of backup super blocks when block-group-tree is enabled - more extensive mount-time checks of device items that could be left after device replace and attempting degraded mount - fix build warning with -Wmaybe-uninitialized on loongarch64-gcc 12 * tag 'for-6.19-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: add extra device item checks at mount btrfs: fix missing fields in superblock backup with BLOCK_GROUP_TREE btrfs: reject new transactions if the fs is fully read-only btrfs: sync read disk super and set block size btrfs: fix Wmaybe-uninitialized warning in replay_one_buffer()
2026-01-20btrfs: add extra device item checks at mountQu Wenruo3-0/+48
[BUG] There is a bug report where after a dev-replace, the replace source device with devid 4 is properly erased (dump tree shows it's the old devid 4), but the target device is still using devid 0. When the user tries to mount the fs degraded, the mount failed with the following errors: BTRFS: device fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 devid 5 transid 1394395 /dev/sda (8:0) scanned by btrfs (261) BTRFS: device fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 devid 6 transid 1394395 /dev/sde (8:64) scanned by btrfs (261) BTRFS: device fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 devid 0 transid 1394395 /dev/sdd (8:48) scanned by btrfs (261) BTRFS: device fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 devid 3 transid 1394395 /dev/sdf (8:80) scanned by btrfs (261) BTRFS info (device sdd): first mount of filesystem 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 BTRFS info (device sdd): using crc32c (crc32c-intel) checksum algorithm BTRFS warning (device sdd): devid 4 uuid 01e2081c-9c2a-4071-b9f4-e1b27e571ff5 is missing BTRFS info (device sdd): bdev <missing disk> errs: wr 84994544, rd 15567, flush 65872, corrupt 0, gen 0 BTRFS info (device sdd): bdev /dev/sdd errs: wr 71489901, rd 0, flush 30001, corrupt 0, gen 0 BTRFS error (device sdd): replace without active item, run 'device scan --forget' on the target device BTRFS error (device sdd): failed to init dev_replace: -117 BTRFS error (device sdd): open_ctree failed: -117 [CAUSE] The devid 0 didn't get its devid updated is its own problem, here I'm only focusing on the mount failure itself. The mount is not caused by the missing device, as the fs has RAID1C3 for metadata and RAID10 for data, thus is completely able to tolerate one missing device. The device tree shows the dev-replace has properly finished: item 7 key (0 DEV_REPLACE 0) itemoff 15931 itemsize 72 src devid -1 cursor left 11091821199360 cursor right 11091821199360 mode ALWAYS state FINISHED write errors 0 uncorrectable read errors 0 ^^^^^^^^ And the chunk tree shows there is no devid 0: leaf 37980736602112 items 23 free space 12548 generation 1394388 owner CHUNK_TREE leaf 37980736602112 flags 0x1(WRITTEN) backref revision 1 fs uuid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 chunk uuid d074c661-6311-4570-b59f-a5c83fd37f8e item 0 key (DEV_ITEMS DEV_ITEM 3) itemoff 16185 itemsize 98 devid 3 total_bytes 20000588955648 bytes_used 8282877984768 io_align 4096 io_width 4096 sector_size 4096 type 0 generation 0 start_offset 0 dev_group 0 seek_speed 0 bandwidth 0 uuid 0d596b69-fb0d-4031-b4af-a301d0868b8b fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 ... Which shows the first device is devid 3. But there is indeed /dev/sdd with devid 0: superblock: bytenr=65536, device=/dev/sdd --------------------------------------------------------- csum_type 0 (crc32c) csum_size 4 csum 0xd4bed87e [match] bytenr 65536 flags 0x1 ( WRITTEN ) magic _BHRfS_M [match] fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 ... uuid_tree_generation 1394388 dev_item.uuid ee6532ad-5442-45f7-87fb-7703e29ed934 dev_item.fsid 84a1ed4a-365c-45c3-a9ee-a7df525dc3c9 [match] dev_item.type 0 dev_item.total_bytes 20000588955648 dev_item.bytes_used 8292541661184 dev_item.io_align 0 dev_item.io_width 0 dev_item.sector_size 0 dev_item.devid 0 <<< So this means device scan will register sdd as devid 0 into the fs, then during btrfs_init_dev_replace(), we located the replace progress item, found the previous replace is finished, but we still need to check if the dev-replace target device (devid 0) exists. If that device exists, we error out showing that error message. But to be honest the end user may not really remember which device is the replace target device, thus not sure what to do in the next step. [ENHANCEMENT] To make the error more obvious, and tell the end user which devices should be unregistered: - Introduce BTRFS_DEV_STATE_ITEM_FOUND flag During device item read from the chunk tree, set the flag for each found device item. - Verify there is no device without the above flag during mount Even missing device should have that flag set. If we found a device without that flag set, it means it's an unexpected one and should be rejected. - More detailed error message on what to do next This will show all unexpected devices and tell the end user to use 'btrfs dev scan --forget' to forget them or remove them before mount. There is an example dmesg where a device of a valid filesystem is modified to have devid 0, then try degraded mount: BTRFS info (device dm-6): first mount of filesystem 7c873869-844c-4b39-bd75-a96148bf4656 BTRFS info (device dm-6): using crc32c checksum algorithm BTRFS warning (device dm-6): devid 3 uuid b4a9f35b-db42-4ac4-b55a-cbf81d3b9683 is missing BTRFS error (device dm-6): devid 0 path /dev/mapper/test-scratch3 is registered but not found in chunk tree BTRFS error (device dm-6): please remove above devices or use 'btrfs device scan --forget <dev>' to unregister them before mount BTRFS error (device dm-6): open_ctree failed: -117 Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-20btrfs: fix missing fields in superblock backup with BLOCK_GROUP_TREEMark Harmstone1-1/+1
When the BLOCK_GROUP_TREE compat_ro flag is set, the extent root and csum root fields are getting missed. This is because EXTENT_TREE_V2 treated these differently, and when they were split off this special-casing was mistakenly assigned to BGT rather than the rump EXTENT_TREE_V2. There's no reason why the existence of the block group tree should mean that we don't record the details of the last commit's extent root and csum root. Fix the code in backup_super_roots() so that the correct check gets made. Fixes: 1c56ab991903 ("btrfs: separate BLOCK_GROUP_TREE compat RO flag from EXTENT_TREE_V2") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-20btrfs: reject new transactions if the fs is fully read-onlyQu Wenruo2-0/+21
[BUG] There is a bug report where a heavily fuzzed fs is mounted with all rescue mount options, which leads to the following warnings during unmount: BTRFS: Transaction aborted (error -22) Modules linked in: CPU: 0 UID: 0 PID: 9758 Comm: repro.out Not tainted 6.19.0-rc5-00002-gb71e635feefc #7 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:find_free_extent_update_loop fs/btrfs/extent-tree.c:4208 [inline] RIP: 0010:find_free_extent+0x52f0/0x5d20 fs/btrfs/extent-tree.c:4611 Call Trace: <TASK> btrfs_reserve_extent+0x2cd/0x790 fs/btrfs/extent-tree.c:4705 btrfs_alloc_tree_block+0x1e1/0x10e0 fs/btrfs/extent-tree.c:5157 btrfs_force_cow_block+0x578/0x2410 fs/btrfs/ctree.c:517 btrfs_cow_block+0x3c4/0xa80 fs/btrfs/ctree.c:708 btrfs_search_slot+0xcad/0x2b50 fs/btrfs/ctree.c:2130 btrfs_truncate_inode_items+0x45d/0x2350 fs/btrfs/inode-item.c:499 btrfs_evict_inode+0x923/0xe70 fs/btrfs/inode.c:5628 evict+0x5f4/0xae0 fs/inode.c:837 __dentry_kill+0x209/0x660 fs/dcache.c:670 finish_dput+0xc9/0x480 fs/dcache.c:879 shrink_dcache_for_umount+0xa0/0x170 fs/dcache.c:1661 generic_shutdown_super+0x67/0x2c0 fs/super.c:621 kill_anon_super+0x3b/0x70 fs/super.c:1289 btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2127 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318 task_work_run+0x1d4/0x260 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x694/0x22f0 kernel/exit.c:971 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 __do_sys_exit_group kernel/exit.c:1123 [inline] __se_sys_exit_group kernel/exit.c:1121 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe8/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x44f639 Code: Unable to access opcode bytes at 0x44f60f. RSP: 002b:00007ffc15c4e088 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000004c32f0 RCX: 000000000044f639 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffffffffffc0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004c32f0 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 </TASK> Since rescue mount options will mark the full fs read-only, there should be no new transaction triggered. But during unmount we will evict all inodes, which can trigger a new transaction, and triggers warnings on a heavily corrupted fs. [CAUSE] Btrfs allows new transaction even on a read-only fs, this is to allow log replay happen even on read-only mounts, just like what ext4/xfs do. However with rescue mount options, the fs is fully read-only and cannot be remounted read-write, thus in that case we should also reject any new transactions. [FIX] If we find the fs has rescue mount options, we should treat the fs as error, so that no new transaction can be started. Reported-by: Jiaming Zhang <r772577952@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CANypQFYw8Nt8stgbhoycFojOoUmt+BoZ-z8WJOZVxcogDdwm=Q@mail.gmail.com/ Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-20btrfs: sync read disk super and set block sizeEdward Adam Davis1-0/+2
When the user performs a btrfs mount, the block device is not set correctly. The user sets the block size of the block device to 0x4000 by executing the BLKBSZSET command. Since the block size change also changes the mapping->flags value, this further affects the result of the mapping_min_folio_order() calculation. Let's analyze the following two scenarios: Scenario 1: Without executing the BLKBSZSET command, the block size is 0x1000, and mapping_min_folio_order() returns 0; Scenario 2: After executing the BLKBSZSET command, the block size is 0x4000, and mapping_min_folio_order() returns 2. do_read_cache_folio() allocates a folio before the BLKBSZSET command is executed. This results in the allocated folio having an order value of 0. Later, after BLKBSZSET is executed, the block size increases to 0x4000, and the mapping_min_folio_order() calculation result becomes 2. This leads to two undesirable consequences: 1. filemap_add_folio() triggers a VM_BUG_ON_FOLIO(folio_order(folio) < mapping_min_folio_order(mapping)) assertion. 2. The syzbot report [1] shows a null pointer dereference in create_empty_buffers() due to a buffer head allocation failure. Synchronization should be established based on the inode between the BLKBSZSET command and read cache page to prevent inconsistencies in block size or mapping flags before and after folio allocation. [1] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:create_empty_buffers+0x4d/0x480 fs/buffer.c:1694 Call Trace: folio_create_buffers+0x109/0x150 fs/buffer.c:1802 block_read_full_folio+0x14c/0x850 fs/buffer.c:2403 filemap_read_folio+0xc8/0x2a0 mm/filemap.c:2496 do_read_cache_folio+0x266/0x5c0 mm/filemap.c:4096 do_read_cache_page mm/filemap.c:4162 [inline] read_cache_page_gfp+0x29/0x120 mm/filemap.c:4195 btrfs_read_disk_super+0x192/0x500 fs/btrfs/volumes.c:1367 Reported-by: syzbot+b4a2af3000eaa84d95d5@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b4a2af3000eaa84d95d5 Signed-off-by: Edward Adam Davis <eadavis@qq.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-20btrfs: fix Wmaybe-uninitialized warning in replay_one_buffer()Qiang Ma1-1/+1
Warning was found when compiling using loongarch64-gcc 12.3.1: $ make CFLAGS_tree-log.o=-Wmaybe-uninitialized In file included from fs/btrfs/ctree.h:21, from fs/btrfs/tree-log.c:12: fs/btrfs/accessors.h: In function 'replay_one_buffer': fs/btrfs/accessors.h:66:16: warning: 'inode_item' may be used uninitialized [-Wmaybe-uninitialized] 66 | return btrfs_get_##bits(eb, s, offsetof(type, member)); \ | ^~~~~~~~~~ fs/btrfs/tree-log.c:2803:42: note: 'inode_item' declared here 2803 | struct btrfs_inode_item *inode_item; | ^~~~~~~~~~ Initialize the inode_item to NULL, the compiler does not seem to see the relation between the first 'wc->log_key.type == BTRFS_INODE_ITEM_KEY' check and the other one that also checks the replay phase. Signed-off-by: Qiang Ma <maqianga@uniontech.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-18Merge tag 'for-6.19-rc5-tag' of ↵Linus Torvalds8-68/+41
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - with large folios in use, fix partial incorrect update of a reflinked range - fix potential deadlock in iget when lookup fails and eviction is needed - in send, validate inline extent type while detecting file holes - fix memory leak after an error when creating a space info - remove zone statistics from sysfs again, the output size limitations make it unusable, we'll do it in another way in another release - test fixes: - return proper error codes from block remapping tests - fix tree root leaks in qgroup tests after errors * tag 'for-6.19-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: remove zoned statistics from sysfs btrfs: fix memory leaks in create_space_info() error paths btrfs: invalidate pages instead of truncate after reflinking btrfs: update the Kconfig string for CONFIG_BTRFS_EXPERIMENTAL btrfs: send: check for inline extents in range_is_hole_in_parent() btrfs: tests: fix return 0 on rmap test failure btrfs: tests: fix root tree leak in btrfs_test_qgroups() btrfs: release path before iget_failed() in btrfs_read_locked_inode()
2026-01-15btrfs: remove zoned statistics from sysfsJohannes Thumshirn1-52/+0
Remove the newly introduced zoned statistics from sysfs, as sysfs can only show a single page this will truncate the output on a busy filesystem. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-12btrfs: fix memory leaks in create_space_info() error pathsJiasheng Jiang1-2/+6
In create_space_info(), the 'space_info' object is allocated at the beginning of the function. However, there are two error paths where the function returns an error code without freeing the allocated memory: 1. When create_space_info_sub_group() fails in zoned mode. 2. When btrfs_sysfs_add_space_info_type() fails. In both cases, 'space_info' has not yet been added to the fs_info->space_info list, resulting in a memory leak. Fix this by adding an error handling label to kfree(space_info) before returning. Fixes: 2be12ef79fe9 ("btrfs: Separate space_info create/update") Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-12btrfs: invalidate pages instead of truncate after reflinkingFilipe Manana1-10/+13
Qu reported that generic/164 often fails because the read operations get zeroes when it expects to either get all bytes with a value of 0x61 or 0x62. The issue stems from truncating the pages from the page cache instead of invalidating, as truncating can zero page contents. This zeroing is not just in case the range is not page sized (as it's commented in truncate_inode_pages_range()) but also in case we are using large folios, they need to be split and the splitting fails. Stealing Qu's comment in the thread linked below: "We can have the following case: 0 4K 8K 12K 16K | | | | | |<---- Extent A ----->|<----- Extent B ------>| The page size is still 4K, but the folio we got is 16K. Then if we remap the range for [8K, 16K), then truncate_inode_pages_range() will get the large folio 0 sized 16K, then call truncate_inode_partial_folio(). Which later calls folio_zero_range() for the [8K, 16K) range first, then tries to split the folio into smaller ones to properly drop them from the cache. But if splitting failed (e.g. racing with other operations holding the filemap lock), the partially zeroed large folio will be kept, resulting the range [8K, 16K) being zeroed meanwhile the folio is still a 16K sized large one." So instead of truncating, invalidate the page cache range with a call to filemap_invalidate_inode(), which besides not doing any zeroing also ensures that while it's invalidating folios, no new folios are added. This helps ensure that buffered reads that happen while a reflink operation is in progress always get either the whole old data (the one before the reflink) or the whole new data, which is what generic/164 expects. Link: https://lore.kernel.org/linux-btrfs/7fb9b44f-9680-4c22-a47f-6648cb109ddf@suse.com/ Reported-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-12btrfs: update the Kconfig string for CONFIG_BTRFS_EXPERIMENTALQu Wenruo1-1/+5
The following new features are missing: - Async checksum - Shutdown ioctl and auto-degradation - Larger block size support Which is dependent on larger folios. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-09Merge tag 'for-6.19-rc4-tag' of ↵Linus Torvalds4-17/+39
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - fix potential NULL pointer dereference when replaying tree log after an error - release path before initializing extent tree to avoid potential deadlock when allocating new inode - on filesystems with block size > page size - fix potential read out of bounds during encoded read of an inline extent - only enforce free space tree if v1 cache is required - print correct tree id in error message * tag 'for-6.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: show correct warning if can't read data reloc tree btrfs: fix NULL pointer dereference in do_abort_log_replay() btrfs: force free space tree for bs > ps cases btrfs: only enforce free space tree if v1 cache is required for bs < ps cases btrfs: release path before initializing extent tree in btrfs_read_locked_inode() btrfs: avoid access-beyond-folio for bs > ps encoded writes
2026-01-09btrfs: send: check for inline extents in range_is_hole_in_parent()Qu Wenruo1-0/+2
Before accessing the disk_bytenr field of a file extent item we need to check if we are dealing with an inline extent. This is because for inline extents their data starts at the offset of the disk_bytenr field. So accessing the disk_bytenr means we are accessing inline data or in case the inline data is less than 8 bytes we can actually cause an invalid memory access if this inline extent item is the first item in the leaf or access metadata from other items. Fixes: 82bfb2e7b645 ("Btrfs: incremental send, fix unnecessary hole writes for sparse files") 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>
2026-01-09btrfs: tests: fix return 0 on rmap test failureNaohiro Aota1-0/+3
In test_rmap_blocks(), we have ret = 0 before checking the results. We need to set it to -EINVAL, so that a mismatching result will return -EINVAL not 0. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-09btrfs: tests: fix root tree leak in btrfs_test_qgroups()Zilin Guan1-3/+3
If btrfs_insert_fs_root() fails, the tmp_root allocated by btrfs_alloc_dummy_root() is leaked because its initial reference count is not decremented. Fix this by calling btrfs_put_root() unconditionally after btrfs_insert_fs_root(). This ensures the local reference is always dropped. Also fix a copy-paste error in the error message where the subvolume root insertion failure was incorrectly logged as "fs root". Co-developed-by: Jianhao Xu <jianhao.xu@seu.edu.cn> Signed-off-by: Jianhao Xu <jianhao.xu@seu.edu.cn> Signed-off-by: Zilin Guan <zilin@seu.edu.cn> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-09btrfs: release path before iget_failed() in btrfs_read_locked_inode()Filipe Manana1-0/+9
In btrfs_read_locked_inode() if we fail to lookup the inode, we jump to the 'out' label with a path that has a read locked leaf and then we call iget_failed(). This can result in a ABBA deadlock, since iget_failed() triggers inode eviction and that causes the release of the delayed inode, which must lock the delayed inode's mutex, and a task updating a delayed inode starts by taking the node's mutex and then modifying the inode's subvolume btree. Syzbot reported the following lockdep splat for this: ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ btrfs-cleaner/8725 is trying to acquire lock: ffff0000d6826a48 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 but task is already holding lock: ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-tree-00){++++}-{4:4}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x198/0x39c kernel/locking/lockdep.c:5889 up_read+0x24/0x3c kernel/locking/rwsem.c:1632 btrfs_tree_read_unlock+0xdc/0x298 fs/btrfs/locking.c:169 btrfs_tree_unlock_rw fs/btrfs/locking.h:218 [inline] btrfs_search_slot+0xa6c/0x223c fs/btrfs/ctree.c:2133 btrfs_lookup_inode+0xd8/0x38c fs/btrfs/inode-item.c:395 __btrfs_update_delayed_inode+0x124/0xed0 fs/btrfs/delayed-inode.c:1032 btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1118 [inline] __btrfs_commit_inode_delayed_items+0x15f8/0x1748 fs/btrfs/delayed-inode.c:1141 __btrfs_run_delayed_items+0x1ac/0x514 fs/btrfs/delayed-inode.c:1176 btrfs_run_delayed_items_nr+0x28/0x38 fs/btrfs/delayed-inode.c:1219 flush_space+0x26c/0xb68 fs/btrfs/space-info.c:828 do_async_reclaim_metadata_space+0x110/0x364 fs/btrfs/space-info.c:1158 btrfs_async_reclaim_metadata_space+0x90/0xd8 fs/btrfs/space-info.c:1226 process_one_work+0x7e8/0x155c kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3427 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 -> #0 (&delayed_node->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [inline] btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326 btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587 evict+0x414/0x928 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput+0x95c/0xad4 fs/inode.c:1966 iget_failed+0xec/0x134 fs/bad_inode.c:248 btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101 btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837 btrfs_run_defrag_inode fs/btrfs/defrag.c:237 [inline] btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrfs/defrag.c:309 cleaner_kthread+0x21c/0x418 fs/btrfs/disk-io.c:1516 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(btrfs-tree-00); lock(&delayed_node->mutex); lock(btrfs-tree-00); lock(&delayed_node->mutex); *** DEADLOCK *** 1 lock held by btrfs-cleaner/8725: #0: ffff0000dbeba878 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x44/0x2ec fs/btrfs/locking.c:145 stack backtrace: CPU: 0 UID: 0 PID: 8725 Comm: btrfs-cleaner Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043 check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598 __mutex_lock kernel/locking/mutex.c:760 [inline] mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812 __btrfs_release_delayed_node+0xa0/0x9b0 fs/btrfs/delayed-inode.c:290 btrfs_release_delayed_node fs/btrfs/delayed-inode.c:315 [inline] btrfs_remove_delayed_node+0x68/0x84 fs/btrfs/delayed-inode.c:1326 btrfs_evict_inode+0x578/0xe28 fs/btrfs/inode.c:5587 evict+0x414/0x928 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput+0x95c/0xad4 fs/inode.c:1966 iget_failed+0xec/0x134 fs/bad_inode.c:248 btrfs_read_locked_inode+0xe1c/0x1234 fs/btrfs/inode.c:4101 btrfs_iget+0x1b0/0x264 fs/btrfs/inode.c:5837 btrfs_run_defrag_inode fs/btrfs/defrag.c:237 [inline] btrfs_run_defrag_inodes+0x520/0xdc4 fs/btrfs/defrag.c:309 cleaner_kthread+0x21c/0x418 fs/btrfs/disk-io.c:1516 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 Fix this by releasing the path before calling iget_failed(). Reported-by: syzbot+c1c6edb02bea1da754d8@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/694530c2.a70a0220.207337.010d.GAE@google.com/ Fixes: 69673992b1ae ("btrfs: push cleanup into btrfs_read_locked_inode()") Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-06btrfs: show correct warning if can't read data reloc treeMark Harmstone1-0/+1
If a filesystem is missing its data reloc tree, we get something like this in dmesg: BTRFS warning (device loop11): failed to read root (objectid=4): -2 BTRFS error (device loop11): open_ctree failed: -2 objectid is BTRFS_DEV_TREE_OBJECTID, but this should actually be the value of BTRFS_DATA_RELOC_TREE_OBJECTID. btrfs_read_roots() prints location.objectid on failure, but this isn't set when reading the data reloc tree. Set location.objectid to the correct value on failure, so that the error message makes sense. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Mark Harmstone <mark@harmstone.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-06btrfs: fix NULL pointer dereference in do_abort_log_replay()Suchit Karunakaran1-1/+1
Coverity reported a NULL pointer dereference issue (CID 1666756) in do_abort_log_replay(). When btrfs_alloc_path() fails in replay_one_buffer(), wc->subvol_path is NULL, but btrfs_abort_log_replay() calls do_abort_log_replay() which unconditionally dereferences wc->subvol_path when attempting to print debug information. Fix this by adding a NULL check before dereferencing wc->subvol_path in do_abort_log_replay(). Fixes: 2753e4917624 ("btrfs: dump detailed info and specific messages on log replay failures") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2026-01-06btrfs: force free space tree for bs > ps casesQu Wenruo1-1/+1
[BUG] Currently we only enforcing the free space tree for bs < ps cases, but with the recently added bs > ps support, we lack the free space tree enforcing, causing explicit v1 cache mount option to fail on bs > ps cases: # mount -o space_cache=v1 /dev/test/scratch1 /mnt/btrfs/ mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/mapper/test-scratch1, missing codepage or helper program, or other error. dmesg(1) may have more information after failed mount system call. # dmesg -t | tail -n7 BTRFS: device fsid ac14a6fa-4ec9-449e-aec9-7d1777bfdc06 devid 1 transid 11 /dev/mapper/test-scratch1 (253:3) scanned by mount (2849) BTRFS info (device dm-3): first mount of filesystem ac14a6fa-4ec9-449e-aec9-7d1777bfdc06 BTRFS info (device dm-3): using crc32c checksum algorithm BTRFS warning (device dm-3): support for block size 8192 with page size 4096 is experimental, some features may be missing BTRFS warning (device dm-3): space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2 BTRFS warning (device dm-3): v1 space cache is not supported for page size 4096 with sectorsize 8192 BTRFS error (device dm-3): open_ctree failed: -22 [FIX] Just enable the same free space tree for bs > ps cases, aligning the behavior to bs < ps cases. 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>
2026-01-06btrfs: only enforce free space tree if v1 cache is required for bs < ps casesQu Wenruo1-7/+5
[BUG] Since the introduction of btrfs bs < ps support, v1 cache was never on the plan due to its hard coded PAGE_SIZE usage, and the future plan to properly deprecate it. However for bs < ps cases, even if 'nospace_cache,clear_cache' mount option is specified, it's never respected and free space tree is always enabled: mkfs.btrfs -f -O ^bgt,fst $dev mount $dev $mnt -o clear_cache,nospace_cache umount $mnt btrfs ins dump-super $dev ... compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) ... This means a different behavior compared to bs >= ps cases. [CAUSE] The forcing usage of v2 space cache is done inside btrfs_set_free_space_cache_settings(), however it never checks if we're even using space cache but always enabling v2 cache. [FIX] Instead unconditionally enable v2 cache, only forcing v2 cache if the old v1 cache is required. Now v2 space cache can be properly disabled on bs < ps cases: mkfs.btrfs -f -O ^bgt,fst $dev mount $dev $mnt -o clear_cache,nospace_cache umount $mnt btrfs ins dump-super $dev ... compat_ro_flags 0x0 ... Fixes: 9f73f1aef98b ("btrfs: force v2 space cache usage for subpage mount") 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>
2026-01-06btrfs: release path before initializing extent tree in btrfs_read_locked_inode()Filipe Manana1-5/+14
In btrfs_read_locked_inode() we are calling btrfs_init_file_extent_tree() while holding a path with a read locked leaf from a subvolume tree, and btrfs_init_file_extent_tree() may do a GFP_KERNEL allocation, which can trigger reclaim. This can create a circular lock dependency which lockdep warns about with the following splat: [6.1433] ====================================================== [6.1574] WARNING: possible circular locking dependency detected [6.1583] 6.18.0+ #4 Tainted: G U [6.1591] ------------------------------------------------------ [6.1599] kswapd0/117 is trying to acquire lock: [6.1606] ffff8d9b6333c5b8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1625] but task is already holding lock: [6.1633] ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x195/0xc60 [6.1646] which lock already depends on the new lock. [6.1657] the existing dependency chain (in reverse order) is: [6.1667] -> #2 (fs_reclaim){+.+.}-{0:0}: [6.1677] fs_reclaim_acquire+0x9d/0xd0 [6.1685] __kmalloc_cache_noprof+0x59/0x750 [6.1694] btrfs_init_file_extent_tree+0x90/0x100 [6.1702] btrfs_read_locked_inode+0xc3/0x6b0 [6.1710] btrfs_iget+0xbb/0xf0 [6.1716] btrfs_lookup_dentry+0x3c5/0x8e0 [6.1724] btrfs_lookup+0x12/0x30 [6.1731] lookup_open.isra.0+0x1aa/0x6a0 [6.1739] path_openat+0x5f7/0xc60 [6.1746] do_filp_open+0xd6/0x180 [6.1753] do_sys_openat2+0x8b/0xe0 [6.1760] __x64_sys_openat+0x54/0xa0 [6.1768] do_syscall_64+0x97/0x3e0 [6.1776] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1784] -> #1 (btrfs-tree-00){++++}-{3:3}: [6.1794] lock_release+0x127/0x2a0 [6.1801] up_read+0x1b/0x30 [6.1808] btrfs_search_slot+0x8e0/0xff0 [6.1817] btrfs_lookup_inode+0x52/0xd0 [6.1825] __btrfs_update_delayed_inode+0x73/0x520 [6.1833] btrfs_commit_inode_delayed_inode+0x11a/0x120 [6.1842] btrfs_log_inode+0x608/0x1aa0 [6.1849] btrfs_log_inode_parent+0x249/0xf80 [6.1857] btrfs_log_dentry_safe+0x3e/0x60 [6.1865] btrfs_sync_file+0x431/0x690 [6.1872] do_fsync+0x39/0x80 [6.1879] __x64_sys_fsync+0x13/0x20 [6.1887] do_syscall_64+0x97/0x3e0 [6.1894] entry_SYSCALL_64_after_hwframe+0x76/0x7e [6.1903] -> #0 (&delayed_node->mutex){+.+.}-{3:3}: [6.1913] __lock_acquire+0x15e9/0x2820 [6.1920] lock_acquire+0xc9/0x2d0 [6.1927] __mutex_lock+0xcc/0x10a0 [6.1934] __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1944] btrfs_evict_inode+0x20b/0x4b0 [6.1952] evict+0x15a/0x2f0 [6.1958] prune_icache_sb+0x91/0xd0 [6.1966] super_cache_scan+0x150/0x1d0 [6.1974] do_shrink_slab+0x155/0x6f0 [6.1981] shrink_slab+0x48e/0x890 [6.1988] shrink_one+0x11a/0x1f0 [6.1995] shrink_node+0xbfd/0x1320 [6.1002] balance_pgdat+0x67f/0xc60 [6.1321] kswapd+0x1dc/0x3e0 [6.1643] kthread+0xff/0x240 [6.1965] ret_from_fork+0x223/0x280 [6.1287] ret_from_fork_asm+0x1a/0x30 [6.1616] other info that might help us debug this: [6.1561] Chain exists of: &delayed_node->mutex --> btrfs-tree-00 --> fs_reclaim [6.1503] Possible unsafe locking scenario: [6.1110] CPU0 CPU1 [6.1411] ---- ---- [6.1707] lock(fs_reclaim); [6.1998] lock(btrfs-tree-00); [6.1291] lock(fs_reclaim); [6.1581] lock(&delayed_node->mutex); [6.1874] *** DEADLOCK *** [6.1716] 2 locks held by kswapd0/117: [6.1999] #0: ffffffffa4ab8ce0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x195/0xc60 [6.1294] #1: ffff8d998344b0e0 (&type->s_umount_key#40){++++}- {3:3}, at: super_cache_scan+0x37/0x1d0 [6.1596] stack backtrace: [6.1183] CPU: 11 UID: 0 PID: 117 Comm: kswapd0 Tainted: G U 6.18.0+ #4 PREEMPT(lazy) [6.1185] Tainted: [U]=USER [6.1186] Hardware name: ASUS System Product Name/PRIME B560M-A AC, BIOS 2001 02/01/2023 [6.1187] Call Trace: [6.1187] <TASK> [6.1189] dump_stack_lvl+0x6e/0xa0 [6.1192] print_circular_bug.cold+0x17a/0x1c0 [6.1194] check_noncircular+0x175/0x190 [6.1197] __lock_acquire+0x15e9/0x2820 [6.1200] lock_acquire+0xc9/0x2d0 [6.1201] ? __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1204] __mutex_lock+0xcc/0x10a0 [6.1206] ? __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1208] ? __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1211] ? __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1213] __btrfs_release_delayed_node.part.0+0x39/0x2f0 [6.1215] btrfs_evict_inode+0x20b/0x4b0 [6.1217] ? lock_acquire+0xc9/0x2d0 [6.1220] evict+0x15a/0x2f0 [6.1222] prune_icache_sb+0x91/0xd0 [6.1224] super_cache_scan+0x150/0x1d0 [6.1226] do_shrink_slab+0x155/0x6f0 [6.1228] shrink_slab+0x48e/0x890 [6.1229] ? shrink_slab+0x2d2/0x890 [6.1231] shrink_one+0x11a/0x1f0 [6.1234] shrink_node+0xbfd/0x1320 [6.1236] ? shrink_node+0xa2d/0x1320 [6.1236] ? shrink_node+0xbd3/0x1320 [6.1239] ? balance_pgdat+0x67f/0xc60 [6.1239] balance_pgdat+0x67f/0xc60 [6.1241] ? finish_task_switch.isra.0+0xc4/0x2a0 [6.1246] kswapd+0x1dc/0x3e0 [6.1247] ? __pfx_autoremove_wake_function+0x10/0x10 [6.1249] ? __pfx_kswapd+0x10/0x10 [6.1250] kthread+0xff/0x240 [6.1251] ? __pfx_kthread+0x10/0x10 [6.1253] ret_from_fork+0x223/0x280 [6.1255] ? __pfx_kthread+0x10/0x10 [6.1257] ret_from_fork_asm+0x1a/0x30 [6.1260] </TASK> This is because: 1) The fsync task is holding an inode's delayed node mutex (for a directory) while calling __btrfs_update_delayed_inode() and that needs to do a search on the subvolume's btree (therefore read lock some extent buffers); 2) The lookup task, at btrfs_lookup(), triggered reclaim with the GFP_KERNEL allocation done by btrfs_init_file_extent_tree() while holding a read lock on a subvolume leaf; 3) The reclaim triggered kswapd which is doing inode eviction for the directory inode the fsync task is using as an argument to btrfs_commit_inode_delayed_inode() - but in that call chain we are trying to read lock the same leaf that the lookup task is holding while calling btrfs_init_file_extent_tree() and doing the GFP_KERNEL allocation. Fix this by calling btrfs_init_file_extent_tree() after we don't need the path anymore and release it in btrfs_read_locked_inode(). Reported-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Link: https://lore.kernel.org/linux-btrfs/6e55113a22347c3925458a5d840a18401a38b276.camel@linux.intel.com/ Fixes: 8679d2687c35 ("btrfs: initialize inode::file_extent_tree after i_mode has been set") 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>