kernel/linux.git/fs/f2fs/super.c, branch v7.1

f2fs: allow empty mount string for Opt_usr|grp|projjquota

2026-04-13T22:50:51+00:00

The fsparam_string_empty() gives an error when mounting without string, since its type is set to fsparam_flag in VFS. So, let's allow the flag as well. This addresses xfstests/f2fs/015 and f2fs/021. Fixes: d18535132523 ("f2fs: separate the options parsing and options checking") Reviewed-by: Daeho Jeong Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix to preserve previous reserve_{blocks,node} value when remount

2026-04-02T16:24:20+00:00

The following steps will change previous value of reserve_{blocks,node}, this dones not match the original intention. 1.mount -t f2fs -o reserve_root=8192 imgfile test_mount/ F2FS-fs (loop56): Mounted with checkpoint version = 1b69f8c7 mount info: /dev/block/loop56 on /data/test_mount type f2fs (xxx,reserve_root=8192,reserve_node=0,resuid=0,resgid=0,xxx) 2.mount -t f2fs -o remount,reserve_root=4096 /data/test_mount F2FS-fs (loop56): Preserve previous reserve_root=8192 check mount info: reserve_root change to 4096 /dev/block/loop56 on /data/test_mount type f2fs (xxx,reserve_root=4096,reserve_node=0,resuid=0,resgid=0,xxx) Prior to commit d18535132523 ("f2fs: separate the options parsing and options checking"), the value of reserve_{blocks,node} was only set during the first mount, along with the corresponding mount option F2FS_MOUNT_RESERVE_{ROOT,NODE} . If the mount option F2FS_MOUNT_RESERVE_{ROOT,NODE} was found to have been set during the mount/remount, the previously value of reserve_{blocks,node} would also be preserved, as shown in the code below. if (test_opt(sbi, RESERVE_ROOT)) { f2fs_info(sbi, "Preserve previous reserve_root=%u", F2FS_OPTION(sbi).root_reserved_blocks); } else { F2FS_OPTION(sbi).root_reserved_blocks = arg; set_opt(sbi, RESERVE_ROOT); } But commit d18535132523 ("f2fs: separate the options parsing and options checking") only preserved the previous mount option; it did not preserve the previous value of reserve_{blocks,node}. Since value of reserve_{blocks,node} value is assigned or not depends on ctx->spec_mask, ctx->spec_mask should be alos handled in f2fs_check_opt_consistency. This patch will clear the corresponding ctx->spec_mask bits in f2fs_check_opt_consistency to preserve the previously values of reserve_{blocks,node} if it already have a value. Fixes: d18535132523 ("f2fs: separate the options parsing and options checking") Signed-off-by: Zhiguo Niu Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: invalidate block device page cache on umount

2026-04-02T16:24:20+00:00

Neither F2FS nor VFS invalidates the block device page cache, which results in reading stale metadata. An example scenario is shown below: Terminal A Terminal B mount /dev/vdb /mnt/f2fs touch mx // ino = 4 sync dump.f2fs -i 4 /dev/vdb// block on "[Y/N]" touch mx2 // ino = 5 sync umount /mnt/f2fs dump.f2fs -i 5 /dev/vdb // block addr is 0 After umount, the block device page cache is not purged, causing `dump.f2fs -i 5 /dev/vdb` to read stale metadata and see inode 5 with block address 0. Btrfs has encountered a similar issue before, the solution there was to call sync_blockdev() and invalidate_bdev() when the device is closed: mail-archive.com/linux-btrfs@vger.kernel.org/msg54188.html For the root user, the f2fs kernel calls sync_blockdev() on umount to flush all cached data to disk, and f2fs-tools can release the page cache by issuing ioctl(fd, BLKFLSBUF) when accessing the device. However, non-root users are not permitted to drop the page cache, and may still observe stale data. This patch calls sync_blockdev() and invalidate_bdev() during umount to invalidate the block device page cache, thereby preventing stale metadata from being read. Note that this may result in an extra sync_blockdev() call on the first device, in both f2fs_put_super() and kill_block_super(). The second call do nothing, as there are no dirty pages left to flush. It ensures that non-root users do not observe stale data. Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix false alarm of lockdep on cp_global_sem lock

2026-04-02T16:24:20+00:00

lockdep reported a potential deadlock: a) TCMU device removal context: - call del_gendisk() to get q->q_usage_counter - call start_flush_work() to get work_completion of wb->dwork b) f2fs writeback context: - in wb_workfn(), which holds work_completion of wb->dwork - call f2fs_balance_fs() to get sbi->gc_lock c) f2fs vfs_write context: - call f2fs_gc() to get sbi->gc_lock - call f2fs_write_checkpoint() to get sbi->cp_global_sem d) f2fs mount context: - call recover_fsync_data() to get sbi->cp_global_sem - call f2fs_check_and_fix_write_pointer() to call blkdev_report_zones() that goes down to blk_mq_alloc_request and get q->q_usage_counter Original callstack is in Closes tag. However, I think this is a false alarm due to before mount returns successfully (context d), we can not access file therein via vfs_write (context c). Let's introduce per-sb cp_global_sem_key, and assign the key for cp_global_sem, so that lockdep can recognize cp_global_sem from different super block correctly. A lot of work are done by Shin'ichiro Kawasaki, thanks a lot for the work. Fixes: c426d99127b1 ("f2fs: Check write pointer consistency of open zones") Cc: stable@kernel.org Reported-and-tested-by: Shin'ichiro Kawasaki Closes: https://lore.kernel.org/linux-f2fs-devel/20260218125237.3340441-1-shinichiro.kawasaki@wdc.com Signed-off-by: Shin'ichiro Kawasaki Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix to do sanity check on dcc->discard_cmd_cnt conditionally

2026-04-02T16:24:19+00:00

Syzbot reported a f2fs bug as below: ------------[ cut here ]------------ kernel BUG at fs/f2fs/segment.c:1900! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 6527 Comm: syz.5.110 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:f2fs_issue_discard_timeout+0x59b/0x5a0 fs/f2fs/segment.c:1900 Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c d6 fe ff ff 48 89 df e8 a8 5e fa fd e9 c9 fe ff ff e8 4e 46 94 fd 90 0f 0b e8 46 46 94 fd 90 <0f> 0b 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 RSP: 0018:ffffc9000494f940 EFLAGS: 00010283 RAX: ffffffff843009ca RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc9001ca78000 RSI: 00000000000029f3 RDI: 00000000000029f4 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100893a431 R12: 1ffff1100893a430 R13: 1ffff1100c2b702c R14: dffffc0000000000 R15: ffff8880449d2160 FS: 00007ffa35fed6c0(0000) GS:ffff88812643d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2b68634000 CR3: 0000000039f62000 CR4: 00000000003526f0 Call Trace: __f2fs_remount fs/f2fs/super.c:2960 [inline] f2fs_reconfigure+0x108a/0x1710 fs/f2fs/super.c:5443 reconfigure_super+0x227/0x8a0 fs/super.c:1080 do_remount fs/namespace.c:3391 [inline] path_mount+0xdc5/0x10e0 fs/namespace.c:4151 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffa37dbda0a The root cause is there will be race condition in between f2fs_ioc_fitrim() and f2fs_remount(): - f2fs_remount - f2fs_ioc_fitrim - f2fs_issue_discard_timeout - __issue_discard_cmd - __drop_discard_cmd - __wait_all_discard_cmd - f2fs_trim_fs - f2fs_write_checkpoint - f2fs_clear_prefree_segments - f2fs_issue_discard - __issue_discard_async - __queue_discard_cmd - __update_discard_tree_range - __insert_discard_cmd - __create_discard_cmd : atomic_inc(&dcc->discard_cmd_cnt); - sanity check on dcc->discard_cmd_cnt (expect discard_cmd_cnt to be zero) This will only happen when fitrim races w/ remount rw, if we remount to readonly filesystem, remount will wait until mnt_pcp.mnt_writers to zero, that means fitrim is not in process at that time. Cc: stable@kernel.org Fixes: 2482c4325dfe ("f2fs: detect bug_on in f2fs_wait_discard_bios") Reported-by: syzbot+62538b67389ee582837a@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/69b07d7c.050a0220.8df7.09a1.GAE@google.com Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: use more generic f2fs_stop_checkpoint()

2026-03-24T17:21:01+00:00

Let's use more generic f2fs_stop_checkpoint() instead of f2fs_handle_critical_error() to handle critical error in f2fs. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

Merge tag 'f2fs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

2026-02-14T17:48:10+00:00

Pull f2fs updates from Jaegeuk Kim: "In this development cycle, we focused on several key performance optimizations: - introducing large folio support to enhance read speeds for immutable files - reducing checkpoint=enable latency by flushing only committed dirty pages - implementing tracepoints to diagnose and resolve lock priority inversion. Additionally, we introduced the packed_ssa feature to optimize the SSA footprint when utilizing large block sizes. Detail summary: Enhancements: - support large folio for immutable non-compressed case - support non-4KB block size without packed_ssa feature - optimize f2fs_enable_checkpoint() to avoid long delay - optimize f2fs_overwrite_io() for f2fs_iomap_begin - optimize NAT block loading during checkpoint write - add write latency stats for NAT and SIT blocks in f2fs_write_checkpoint - pin files do not require sbi->writepages lock for ordering - avoid f2fs_map_blocks() for consecutive holes in readpages - flush plug periodically during GC to maximize readahead effect - add tracepoints to catch lock overheads - add several sysfs entries to tune internal lock priorities Fixes: - fix lock priority inversion issue - fix incomplete block usage in compact SSA summaries - fix to show simulate_lock_timeout correctly - fix to avoid mapping wrong physical block for swapfile - fix IS_CHECKPOINTED flag inconsistency issue caused by concurrent atomic commit and checkpoint writes - fix to avoid UAF in f2fs_write_end_io()" * tag 'f2fs-for-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (61 commits) f2fs: sysfs: introduce critical_task_priority f2fs: introduce trace_f2fs_priority_update f2fs: fix lock priority inversion issue f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin f2fs: fix incomplete block usage in compact SSA summaries f2fs: decrease maximum flush retry count in f2fs_enable_checkpoint() f2fs: optimize NAT block loading during checkpoint write f2fs: change size parameter of __has_cursum_space() to unsigned int f2fs: add write latency stats for NAT and SIT blocks in f2fs_write_checkpoint f2fs: pin files do not require sbi->writepages lock for ordering f2fs: fix to show simulate_lock_timeout correctly f2fs: introduce FAULT_SKIP_WRITE f2fs: check skipped write in f2fs_enable_checkpoint() Revert "f2fs: add timeout in f2fs_enable_checkpoint()" f2fs: fix to unlock folio in f2fs_read_data_large_folio() f2fs: fix error path handling in f2fs_read_data_large_folio() f2fs: use folio_end_read f2fs: fix to avoid mapping wrong physical block for swapfile f2fs: avoid f2fs_map_blocks() for consecutive holes in readpages f2fs: advance index and offset after zeroing in large folio read ...

f2fs: sysfs: introduce critical_task_priority

2026-02-10T20:53:21+00:00

This patch introduces /sys/fs/f2fs//critical_task_priority, w/ this new sysfs interface, we can tune priority of f2fs_ckpt thread and f2fs_gc thread. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim