linux.git/fs/f2fs/segment.c, branch v7.2-rc2

f2fs: avoid unnecessary sanity check on ckpt_valid_blocks

2026-06-22T19:52:38+00:00

The calculation of sec->ckpt_valid_blocks are the same in both
set_ckpt_valid_blocks() and sanity_check_valid_blocks(), so it
doesn't necessary to call sanity_check_valid_blocks() right after
set_ckpt_valid_blocks().

Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

Revert: "f2fs: check in-memory sit version bitmap"

2026-06-22T19:52:35+00:00

Commit ae27d62e6bef ("f2fs: check in-memory sit version bitmap") added
a mirror for sit version bitmap, it expects to detect in-memory
corruption, however we never got any reports from the check points
for almost decade, let's remove the code, it can help to save
memories.

Cc: wallentx 
Suggested-by: Jaegeuk Kim 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

Revert: "f2fs: check in-memory block bitmap"

2026-06-22T19:52:35+00:00

Commit 355e78913c0d ("f2fs: check in-memory block bitmap") added
a mirror for valid block bitmap, it expects to detect in-memory
corruption, however we never got any reports from the check points
for almost decade, let's remove the code, it can help to save
memories.

Cc: wallentx 
Suggested-by: Jaegeuk Kim 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix potential deadlock in gc_merge path of f2fs_balance_fs()

2026-06-22T19:52:34+00:00

When we mount device w/ gc_merge mount option, we may suffer below
potential deadlock:

Kworker					GC trehad			Truncator
- f2fs_write_cache_pages
 - f2fs_write_single_data_page
  - f2fs_do_write_data_page
   - folio_start_writeback  --- set writeback flag on folio
   - f2fs_outplace_write_data
   : cached folio in internal bio cache
  - f2fs_balance_fs
   - wake_up(gc_thread)
   : wake up gc thread to run foreground GC
   - finish_wait(fggc_wq)
   : wait on the waitqueue --- wait on GC thread to finish the work
									- truncate_inode_pages_range
									 - __filemap_get_folio(, FGP_LOCK)  --- lock folio
									 - truncate_inode_partial_folio
									  - folio_wait_writeback            --- wait on writeback being cleared
					- do_garbage_collect
					 - move_data_page
					  - f2fs_get_lock_data_folio
					   - lock on folio  --- blocked on folio's lock

In order to avoid such deadlock, let's call below functions to commit
cached bios in GC_MERGE path of f2fs_balance_fs() as the same as we did
in NOGC_MERGE path.
- f2fs_submit_merged_write(sbi, DATA);
- f2fs_submit_all_merged_ipu_writes(sbi);

Cc: stable@kernel.org
Fixes: 351df4b20115 ("f2fs: add segment operations")
Cc: Ruipeng Qi 
Reported: Sandeep Dhavale 
Signed-off-by: Chao Yu 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix potential deadlock in f2fs_balance_fs()

2026-05-22T03:49:06+00:00

When the f2fs filesystem space is nearly exhausted, we encounter deadlock
issues as below:

INFO: task A:1890 blocked for more than 120 seconds.
      Tainted: G           O       6.12.41-g3fe07ddf05ab #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:A    state:D stack:0     pid:1890  tgid:1626  ppid:1153   flags:0x00000204
Call trace:
 __switch_to+0xf4/0x158
 __schedule+0x27c/0x908
 schedule+0x3c/0x118
 io_schedule+0x44/0x68
 folio_wait_bit_common+0x174/0x370
 folio_wait_bit+0x20/0x38
 folio_wait_writeback+0x54/0xc8
 truncate_inode_partial_folio+0x70/0x1e0
 truncate_inode_pages_range+0x1b0/0x450
 truncate_pagecache+0x54/0x88
 f2fs_file_write_iter+0x3e8/0xb80
 do_iter_readv_writev+0xf0/0x1e0
 vfs_writev+0x138/0x2c8
 do_writev+0x88/0x130
 __arm64_sys_writev+0x28/0x40
 invoke_syscall+0x50/0x120
 el0_svc_common.constprop.0+0xc8/0xf0
 do_el0_svc+0x24/0x38
 el0_svc+0x30/0xf8
 el0t_64_sync_handler+0x120/0x130
 el0t_64_sync+0x190/0x198

INFO: task kworker/u8:11:2680853 blocked for more than 120 seconds.
      Tainted: G           O       6.12.41-g3fe07ddf05ab #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:11   state:D stack:0     pid:2680853 tgid:2680853 ppid:2      flags:0x00000208
Workqueue: writeback wb_workfn (flush-254:0)
Call trace:
 __switch_to+0xf4/0x158
 __schedule+0x27c/0x908
 schedule+0x3c/0x118
 io_schedule+0x44/0x68
 folio_wait_bit_common+0x174/0x370
 __filemap_get_folio+0x214/0x348
 pagecache_get_page+0x20/0x70
 f2fs_get_read_data_page+0x150/0x3e8
 f2fs_get_lock_data_page+0x2c/0x160
 move_data_page+0x50/0x478
 do_garbage_collect+0xd38/0x1528
 f2fs_gc+0x240/0x7e0
 f2fs_balance_fs+0x1a0/0x208
 f2fs_write_single_data_page+0x6e4/0x730
 f2fs_write_cache_pages+0x378/0x9b0
 f2fs_write_data_pages+0x2e4/0x388
 do_writepages+0x8c/0x2c8
 __writeback_single_inode+0x4c/0x498
 writeback_sb_inodes+0x234/0x4a8
 __writeback_inodes_wb+0x58/0x118
 wb_writeback+0x2f8/0x3c0
 wb_workfn+0x2c4/0x508
 process_one_work+0x180/0x408
 worker_thread+0x258/0x368
 kthread+0x118/0x128
 ret_from_fork+0x10/0x200

INFO: task kworker/u8:8:2641297 blocked for more than 120 seconds.
      Tainted: G           O       6.12.41-g3fe07ddf05ab #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:8    state:D stack:0     pid:2641297 tgid:2641297 ppid:2      flags:0x00000208
Workqueue: writeback wb_workfn (flush-254:0)
Call trace:
 __switch_to+0xf4/0x158
 __schedule+0x27c/0x908
 rt_mutex_schedule+0x30/0x60
 __rt_mutex_slowlock_locked.constprop.0+0x460/0x8a8
 rwbase_write_lock+0x24c/0x378
 down_write+0x1c/0x30
 f2fs_balance_fs+0x184/0x208
 f2fs_write_inode+0xf4/0x328
 __writeback_single_inode+0x370/0x498
 writeback_sb_inodes+0x234/0x4a8
 __writeback_inodes_wb+0x58/0x118
 wb_writeback+0x2f8/0x3c0
 wb_workfn+0x2c4/0x508
 process_one_work+0x180/0x408
 worker_thread+0x258/0x368
 kthread+0x118/0x128
 ret_from_fork+0x10/0x20

INFO: task B:1902 blocked for more than 120 seconds.
      Tainted: G           O       6.12.41-g3fe07ddf05ab #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:B     state:D stack:0     pid:1902  tgid:1626  ppid:1153   flags:0x0000020c
Call trace:
 __switch_to+0xf4/0x158
 __schedule+0x27c/0x908
 rt_mutex_schedule+0x30/0x60
 __rt_mutex_slowlock_locked.constprop.0+0x460/0x8a8
 rwbase_write_lock+0x24c/0x378
 down_write+0x1c/0x30
 f2fs_balance_fs+0x184/0x208
 f2fs_map_blocks+0x94c/0x1110
 f2fs_file_write_iter+0x228/0xb80
 do_iter_readv_writev+0xf0/0x1e0
 vfs_writev+0x138/0x2c8
 do_writev+0x88/0x130
 __arm64_sys_writev+0x28/0x40
 invoke_syscall+0x50/0x120
 el0_svc_common.constprop.0+0xc8/0xf0
 do_el0_svc+0x24/0x38
 el0_svc+0x30/0xf8
 el0t_64_sync_handler+0x120/0x130
 el0t_64_sync+0x190/0x198

INFO: task sync:2769849 blocked for more than 120 seconds.
      Tainted: G           O       6.12.41-g3fe07ddf05ab #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:sync            state:D stack:0     pid:2769849 tgid:2769849 ppid:736    flags:0x0000020c
Call trace:
 __switch_to+0xf4/0x158
 __schedule+0x27c/0x908
 schedule+0x3c/0x118
 wb_wait_for_completion+0xb0/0xe8
 sync_inodes_sb+0xc8/0x2b0
 sync_inodes_one_sb+0x24/0x38
 iterate_supers+0xa8/0x138
 ksys_sync+0x54/0xc8
 __arm64_sys_sync+0x18/0x30
 invoke_syscall+0x50/0x120
 el0_svc_common.constprop.0+0xc8/0xf0
 do_el0_svc+0x24/0x38
 el0_svc+0x30/0xf8
 el0t_64_sync_handler+0x120/0x130
 el0t_64_sync+0x190/0x198

The root cause is a potential deadlock between the following tasks:

kworker/u8:11				Thread A
- f2fs_write_single_data_page
 - f2fs_do_write_data_page
  - folio_start_writeback(X)
  - f2fs_outplace_write_data
   - bio_add_folio(X)
 - folio_unlock(X)
					- truncate_inode_pages_range
					 - __filemap_get_folio(X, FGP_LOCK)
					 - truncate_inode_partial_folio(X)
					  - folio_wait_writeback(X)
 - f2fs_balance_fs
  - f2fs_gc
   - do_garbage_collect
    - move_data_page
     - f2fs_get_lock_data_page
      - __filemap_get_folio(X, FGP_LOCK)

Both threads try to access folio X. Thread A holds the lock but waits
for writeback, while kworker waits for the lock. This causes a deadlock.

Other threads also enter D state, waiting for locks such as gc_lock and
writepages.

OPU/IPU DATA folio are all affected by this issue. To avoid such
potential deadlocks, always commit these cached folios before
triggering f2fs_gc() in f2fs_balance_fs().

Suggested-by: Chao Yu 
Reviewed-by: Chao Yu 
Signed-off-by: Ruipeng Qi 
Signed-off-by: Jaegeuk Kim

f2fs: support to report fserror

2026-05-22T03:49:06+00:00

This patch supports to report fserror, it provides another way to let
userspace to monitor filesystem level error. In addition, it exports
/sys/fs/f2fs/features/fserror once f2fs kernel module start to support
the new feature, then generic/791 of fstests can notice the feature,
and verify validation of fserror report.

Cc: Darrick J. Wong 
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: map data writes to FDP streams

2026-05-22T03:49:06+00:00

From: Wenjie Qi 

F2FS already classifies DATA writes using its existing hot, warm and cold
temperature policy, but it only passes that intent down as a write hint.
That hint alone is not sufficient for NVMe FDP placement, because the
current NVMe command path consumes `bio->bi_write_stream` rather than
`bio->bi_write_hint` when selecting a placement ID.

When the target block device exposes write streams, map the existing F2FS
DATA temperature classes onto stream IDs and set `bio->bi_write_stream`
for both buffered and direct writes. If the device exposes no write
streams, keep the current behavior by leaving the stream unset.

The stream mapping is evaluated against the target block device of each
bio, so the existing per-device fallback behavior stays unchanged for
multi-device filesystems. Existing blkzoned restrictions also remain in
place.

The mapping is intentionally small and deterministic:

- 1 stream: hot, warm and cold all use stream 1
- 2 streams: hot/warm use 1, cold uses 2
- 3+ streams: hot uses 1, warm uses 2, cold uses 3

Signed-off-by: Wenjie Qi 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: fix to freeze GC and discard threads quickly

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

Suspend can fail if kernel threads do not freeze for a while.
f2fs_gc and f2fs_discard threads can perform long-running operations
that prevent them from reaching a freeze point in a timely manner.

This patch adds explicit freezing checks in the following locations:
1. f2fs_gc: Added a check at the 'retry' label to exit the loop quickly
   if freezing is requested, especially during heavy GC rounds.
2. __issue_discard_cmd: Added a 'suspended' flag to break both inner and
   outer loops during discard command issuance if freezing is detected
   after at least one command has been issued.
3. __issue_discard_cmd_orderly: Added a similar check for orderly discard
   to ensure responsiveness.

These checks ensure that the threads release locks safely and enter the
frozen state.

Signed-off-by: Daeho Jeong 
Reviewed-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: drop unused sbi parameter from f2fs_in_warm_node_list()

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

The sbi parameter in f2fs_in_warm_node_list() is not used. Remove it to
simplify the function.

Signed-off-by: Yongpeng Yang 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim