kernel/git/stable/linux.git/fs/btrfs/super.c, branch master

Merge tag 'for-7.2-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2026-07-28T15:13:45+00:00

Pull btrfs fixes from David Sterba: "Zoned mode: - fix assertion and handle case of finished zone and truncated extent - fix zone metadata write pointer on actual zone reset - fix deadlock caused metadata writeback and transaction commit - fix return value reuse leading to confusion about chunk reservations raid56 scrub: - fix tracking of sector checksums when there are not checksums found - fix inverted logic when submitting parity read bio mount/remount fixes: - fix leaking 'remount in progress' state which can break other operations to work (qgroup rescan, autodefrag, reclaim) - adjust using global block reserve after read-only mount when using rescue= option - handle missing raid stripe tree when mounted with 'ignorebadroots' Misc: - fix -Wmaybe-uninitialized warning in GET_CSUMS ioctl" * tag 'for-7.2-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: raid56: fix scrub read assembly submitting no reads btrfs: zoned: skip fully truncated ordered extents at zone finish btrfs: initialize 'args' to avoid compiler warning in btrfs_ioctl_get_csums() btrfs: zoned: fix missing chunk metadata reservation btrfs: raid56: fix an incorrect csum skip during scrub btrfs: report missing raid stripe tree root during lookup btrfs: skip global block reserve accounting for rescue mounts btrfs: zoned: reset meta_write_pointer on zone reset btrfs: zoned: fix deadlock between metadata writeback and transaction commit btrfs: fix leaking BTRFS_FS_STATE_REMOUNTING flag

fs: push nr_cached_objects memcg gating into individual filesystems

2026-07-23T09:35:02+00:00

Commit 0baad6f9b997 ("fs/super: skip non-memcg-aware nr_cached_objects in memcg slab shrink") added a check in fs/super.c that skipped every ->nr_cached_objects() hook whenever the shrinker was invoked for a non-root memcg, on the assumption that none of them honour sc->memcg. That assumption is wrong for XFS, whose inode-reclaim hook is intentionally driven from per-memcg contexts to free memcg-charged slab. Encoding a blanket "never memcg-aware" policy in fs/super.c short-circuits that path. Push the check down into the callbacks whose counters really are irrelevant to per-memcg reclaim - btrfs_nr_cached_objects() and shmem_unused_huge_count() - and drop the fs/super.c gate. Each filesystem can now lift the restriction independently if its counter later grows memcg awareness, without touching fs/super.c. Introduce mem_cgroup_shrink_is_root() in so the callbacks don't open-code "sc->memcg is NULL or root". Fixes: 0baad6f9b997 ("fs/super: skip non-memcg-aware nr_cached_objects in memcg slab shrink") Acked-by: Qi Zheng Reviewed-by: Jan Kara Reviewed-by: Shakeel Butt Signed-off-by: Usama Arif Link: https://patch.msgid.link/20260715103516.2410175-1-usama.arif@linux.dev Acked-by: David Sterba Reviewed-by: Baolin Wang Signed-off-by: Christian Brauner (Amutable)

btrfs: fix leaking BTRFS_FS_STATE_REMOUNTING flag

2026-07-21T04:39:39+00:00

[BUG] The following script can lead to unexpected qgroup rescan failure: # mkfs.btrfs -f -O quota $dev # mount $dev $mnt # mount -o remount,rescue=ibadroots $mnt ^^^^^ This above command is expected to fail # btrfs quota rescan -w $mnt ^^^^^ The above qgroup rescan is not expected to fail # btrfs qgroup show $mnt WARNING: qgroup data inconsistent, rescan recommended Qgroupid Referenced Exclusive Path -------- ---------- --------- ---- 0/5 16.00KiB 16.00KiB The above short script will be converted to a proper fstests case. [CAUSE] Inside btrfs_reconfigure(), if either btrfs_check_options() or btrfs_check_features() failed, we will always have BTRFS_FS_STATE_REMOUNTING set for the fs until the next successful remount. That BTRFS_FS_STATE_REMOUNTING flag will interrupt several operations, including: - Qgroup rescan - Auto defrag - Space reclaim [FIX] Change the error handling of btrfs_check_options() and btrfs_check_features() to goto restore label. Fixes: eddb1a433f26 ("btrfs: add reconfigure callback for fs_context") Reviewed-by: Johannes Thumshirn Signed-off-by: Qu Wenruo Signed-off-by: David Sterba

Merge tag 'for-7.2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2026-06-16T06:38:02+00:00

Pull btrfs updates from David Sterba: "The most noticeable change is to enable large folios by default, it's been in testing for a few releases. Related to that is huge folio support (still under experimental config). Otherwise a few ioctl updates, performance improvements and usual fixes and core changes. User visible changes: - enable large folios by default, added in 6.17 (under experimental build), no feature limitations, a big change internally - new ioctl to return raw checksums to userspace (a bit tricky given compression and tail extents), can be used for mkfs and deduplication optimizations - provide stable UUID for e.g. overlayfs and temp_fsid, also reflected in statvfs() field f_fsid, internal dev_t is hashed in to allow cloning - add 32bit compat version of GET_SUBVOL_INFO ioctl - in experimental build, support huge folios (up to 2M) Performance related improvements/changes: - limit bio size to the estimated optimum derived from the queue, this prevents build up of too much data for writeback, which could cause latency spikes (reported improvement 15% on sequential writes) - don't force direct IO to be serialized, forgotten change during mount API port, brings back +60% of throughput - lockless calculation of number of shrinkable extent maps, improve performance with many memcg allocated objects Notable fixes: - in zoned mode, fix a deadlock due to zone reclaim and relocation when space needs to be flushed - don't trim device which is internally not tracked as writeable (e.g. when missing device is being rescanned) - fix deadlock when cloning inline extent and mounted with flushoncommit - fix false IO failures after direct IO falls back to buffered write in some cases Core: - remove COW fixup mechanism completely; detect and fix changes to pages outside of filesystem tracking, guaranteed since 5.8, grace period is over - remove 2K block size support, experimental to test subpage code on x86_64 but now it would block folio changes - tree-checker improvements of: - free-space cache and tree items - root reference and backref items - extent state exceptions in reloc tree - subpage mode updates: - code optimizations, simplify tracking bitmaps - re-enable readahead of compressed extent - extend bitmap size to cover huge folios - add tracepoints related to sync, tree-log and transactions - device stats item tracking unification, remove item if there are no stats recorded, also don't leave stale stats on replaced device - allow extent buffer pages to be allocated as movable, to help page migration - added checks for proper extent buffer release - btrfs.ko code size reduction due to transaction abort call simplifications - several struct size reductions - more auto free conversions - more verbose assertions" * tag 'for-7.2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (130 commits) btrfs: fix use-after-free after relocation failure with concurrent COW btrfs: move WARN_ON on unexpected error in __add_tree_block() btrfs: move locking into btrfs_get_reloc_bg_bytenr() btrfs: lzo: reject compressed segment that overflows the compressed input btrfs: retry faulting in the pages after a zero sized short direct write btrfs: fix incorrect buffered IO fallback for append direct writes btrfs: fix false IO failure after falling back to buffered write btrfs: use verbose assertions in backref.c btrfs: print a message when a missing device re-appears btrfs: do not trim a device which is not writeable btrfs: return real error after lookup failure in btrfs_ioctl_default_subvol() btrfs: use mapping shared locking for reading super block btrfs: use lockless read in nr_cached_objects shrinker callback btrfs: switch local indicator variables to bools btrfs: send: pass bool for pending_move and refs_processed parameters btrfs: use shifts for sectorsize and nodesize btrfs: fix deadlock cloning inline extent when using flushoncommit btrfs: allocate eb-attached btree pages as movable btrfs: add 32-bit compat ioctl for BTRFS_IOC_GET_SUBVOL_INFO btrfs: derive f_fsid from on-disk fsid and dev_t ...

btrfs: use lockless read in nr_cached_objects shrinker callback

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

Under heavy memcg-driven slab reclaim with many memcgs and CPUs, shrink_slab_memcg() invokes the per-superblock count callback once per (memcg, NUMA node) tuple. For btrfs that callback reaches percpu_counter_sum_positive() on fs_info->evictable_extent_maps, which takes the percpu_counter's raw spinlock with IRQs disabled and walks every online CPU. With hundreds of memcgs driving reclaim on a host with dozens of CPUs, this counter lock becomes a global serialization point: profiles show CPU pinned in the spin_lock_irqsave acquire under __percpu_counter_sum, with cross-CPU IPIs hitting csd_lock_wait_toolong while waiting for spinning vCPUs. The shrinker count is advisory -- super_cache_count() already notes "counts can change between super_cache_count and super_cache_scan, so we really don't need locks here." Use percpu_counter_read_positive(), which is lockless. Worst-case skew is bounded by batch * num_online_cpus (a few thousand), negligible compared to the millions of extent maps a busy filesystem accumulates and well within the noise that the shrinker already tolerates. Tested-by: Boris Burkov Reviewed-by: Qu Wenruo Reviewed-by: Shakeel Butt Signed-off-by: Ben Maurer Signed-off-by: David Sterba

btrfs: switch local indicator variables to bools

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

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

btrfs: derive f_fsid from on-disk fsid and dev_t

2026-06-09T16:22:45+00:00

The f_fsid was originally derived from fs_devices->fsid and the subvolume root ID. However, when temp_fsid is active, fs_devices->fsid is randomized, making the standard derivation inconsistent. Since metadata_uuid is optional, it is not a reliable alternative. This patch instead retrieves the on-disk UUID from fs_info->super_copy->fsid. To prevent f_fsid collisions between original and cloned filesystems, this implementation hashes the dev_t for single-device btrfs filesystems to ensure uniqueness. This is limited to single-device filesystems as cloned mounts are currently only supported for that configuration. Note that f_fsid will change if the device is replaced. Additionally, since the kernel cannot distinguish between the original and the cloned filesystem, this new f_fsid derivation is applied to both. Link: https://lore.kernel.org/linux-btrfs/cover.1772095546.git.asj@kernel.org/ Link: https://lore.kernel.org/linux-btrfs/cover.1774092915.git.asj@kernel.org/ Signed-off-by: Anand Jain Signed-off-by: David Sterba

btrfs: zoned: don't account data relocation space-info in statfs free space

2026-06-09T16:22:44+00:00

Don't account the free space in a data relocation space-info sub-group as usable free space in statfs. This is misleading as no user allocations can be made in this space-info sub-group. It is only a target for relocation. Fixes: f92ee31e031c ("btrfs: introduce btrfs_space_info sub-group") Reviewed-by: Boris Burkov Reviewed-by: Naohiro Aota Signed-off-by: Johannes Thumshirn Signed-off-by: David Sterba

btrfs: tracepoints: add trace event for btrfs_log_inode()

2026-06-08T13:53:34+00:00

btrfs_log_inode() is one of the most important steps called during a fsync, as well as during rename and link operations on inodes that were previously logged. Add trace events for when entering and exiting that function. Reviewed-by: Johannes Thumshirn Signed-off-by: Filipe Manana Signed-off-by: David Sterba

btrfs: don't force DIO writes to be serialized

2026-06-08T13:53:31+00:00

Before btrfs switched to the new mount API in 2023, we were setting SB_NOSEC in btrfs_mount_root(). This flag tells the VFS that the filesystem may have files which don't have security xattrs, enabling it to do some optimizations. Unfortunately this was missed in the transition, meaning that IS_NOSEC will always return false for a btrfs inode. This means that btrfs_direct_write() calls will always get the inode lock exclusively, meaning that DIO writes to the same file will be serialized. On my machine, this one-line change results in a ~59% improvement in DIO throughput: Before patch: test: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=64 ... fio-3.39 Starting 32 processes test: Laying out IO file (1 file / 1024MiB) Jobs: 32 (f=32): [w(32)][100.0%][w=764MiB/s][w=195k IOPS][eta 00m:00s] test: (groupid=0, jobs=32): err= 0: pid=586: Wed Apr 22 13:03:04 2026 write: IOPS=202k, BW=787MiB/s (826MB/s)(46.1GiB/60012msec); 0 zone resets bw ( KiB/s): min=498714, max=1199892, per=100.00%, avg=806659.03, stdev=4229.94, samples=3808 iops : min=124677, max=299971, avg=201661.82, stdev=1057.49, samples=3808 cpu : usr=0.32%, sys=1.27%, ctx=8329204, majf=0, minf=1163 IO depths : 1=0.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=100.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0% issued rwts: total=0,12094328,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=64 Run status group 0 (all jobs): WRITE: bw=787MiB/s (826MB/s), 787MiB/s-787MiB/s (826MB/s-826MB/s), io=46.1GiB (49.5GB), run=60012-60012msec After patch: test: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=64 ... fio-3.39 Starting 32 processes test: Laying out IO file (1 file / 1024MiB) Jobs: 32 (f=32): [w(32)][100.0%][w=1255MiB/s][w=321k IOPS][eta 00m:00s] test: (groupid=0, jobs=32): err= 0: pid=572: Wed Apr 22 13:13:46 2026 write: IOPS=320k, BW=1250MiB/s (1311MB/s)(73.3GiB/60003msec); 0 zone resets bw ( MiB/s): min= 619, max= 2289, per=100.00%, avg=1251.28, stdev= 9.64, samples=3808 iops : min=158538, max=586025, avg=320320.80, stdev=2468.97, samples=3808 cpu : usr=0.35%, sys=11.50%, ctx=1584847, majf=0, minf=1160 IO depths : 1=0.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=100.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0% issued rwts: total=0,19203309,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=64 Run status group 0 (all jobs): WRITE: bw=1250MiB/s (1311MB/s), 1250MiB/s-1250MiB/s (1311MB/s-1311MB/s), io=73.3GiB (78.7GB), run=60003-60003msec The script to reproduce that: #!/bin/bash mkfs.btrfs -f /dev/nvme0n1 mount /dev/nvme0n1 /mnt/test mkdir /mnt/test/nocow chattr +C /mnt/test/nocow fio /root/test.fio # cat /root/test.fio [global] rw=randwrite ioengine=io_uring iodepth=64 size=1g direct=1 startdelay=20 force_async=4 ramp_time=5 runtime=60 group_reporting=1 numjobs=32 time_based disk_util=0 clat_percentiles=0 disable_lat=1 disable_clat=1 disable_slat=1 filename=/mnt/test/nocow/fiofile [test] name=test bs=4k stonewall This was on a VM with 8 cores and 8GB of RAM, with a real NVMe exposed through PCI passthrough. The figures for XFS and ext4 in comparison are both about ~3GB/s. Fixes: ad21f15b0f79 ("btrfs: switch to the new mount API") Signed-off-by: Mark Harmstone Signed-off-by: David Sterba