* [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs()
@ 2026-03-25 13:37 ruipengqi
2026-04-20 1:41 ` Ruipeng Qi
2026-04-20 7:35 ` Chao Yu
0 siblings, 2 replies; 5+ messages in thread
From: ruipengqi @ 2026-03-25 13:37 UTC (permalink / raw)
To: jaegeuk; +Cc: chao, linux-f2fs-devel, linux-kernel, Ruipeng Qi
From: Ruipeng Qi <ruipengqi3@gmail.com>
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 //0xfffffe0d6ca08300
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.
To avoid this potential deadlock, always call f2fs_submit_merged_write
before triggering f2fs_gc in f2fs_balance_fs.
Signed-off-by: Ruipeng Qi <ruipengqi3@gmail.com>
---
fs/f2fs/segment.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6a97fe76712b..b58299e49c23 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -454,6 +454,20 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
io_schedule();
finish_wait(&sbi->gc_thread->fggc_wq, &wait);
} else {
+
+ /*
+ * Before triggering foreground GC, submit all cached DATA
+ * write bios. During writeback, pages may be added to
+ * write_io[DATA].bio with PG_writeback set but the bio not
+ * yet submitted. If GC's move_data_page() blocks on
+ * __folio_lock() for such a folio, and the lock holder waits
+ * for PG_writeback to clear via VFS folio_wait_writeback()
+ * neither thread can make progress. Flushing here ensures
+ * the bio completion callback can clear PG_writeback.
+ */
+
+ f2fs_submit_merged_write(sbi, DATA);
+
struct f2fs_gc_control gc_control = {
.victim_segno = NULL_SEGNO,
.init_gc_type = f2fs_sb_has_blkzoned(sbi) ?
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() 2026-03-25 13:37 [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() ruipengqi @ 2026-04-20 1:41 ` Ruipeng Qi 2026-04-20 7:35 ` Chao Yu 1 sibling, 0 replies; 5+ messages in thread From: Ruipeng Qi @ 2026-04-20 1:41 UTC (permalink / raw) To: jaegeuk; +Cc: chao, linux-f2fs-devel, linux-kernel On 2026/3/25 21:37, ruipengqi wrote: > From: Ruipeng Qi<ruipengqi3@gmail.com> > > 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 //0xfffffe0d6ca08300 > 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. > > To avoid this potential deadlock, always call f2fs_submit_merged_write > before triggering f2fs_gc in f2fs_balance_fs. > > Signed-off-by: Ruipeng Qi<ruipengqi3@gmail.com> > --- > fs/f2fs/segment.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 6a97fe76712b..b58299e49c23 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -454,6 +454,20 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) > io_schedule(); > finish_wait(&sbi->gc_thread->fggc_wq, &wait); > } else { > + > + /* > + * Before triggering foreground GC, submit all cached DATA > + * write bios. During writeback, pages may be added to > + * write_io[DATA].bio with PG_writeback set but the bio not > + * yet submitted. If GC's move_data_page() blocks on > + * __folio_lock() for such a folio, and the lock holder waits > + * for PG_writeback to clear via VFS folio_wait_writeback() > + * neither thread can make progress. Flushing here ensures > + * the bio completion callback can clear PG_writeback. > + */ > + > + f2fs_submit_merged_write(sbi, DATA); > + > struct f2fs_gc_control gc_control = { > .victim_segno = NULL_SEGNO, > .init_gc_type = f2fs_sb_has_blkzoned(sbi) ? Hi jaegeuk, chao Gentle ping on this patch. Could you please take a look when you have time? If there are any issues with the patch, I'm happy to address them in a new version. Thanks ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() 2026-03-25 13:37 [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() ruipengqi 2026-04-20 1:41 ` Ruipeng Qi @ 2026-04-20 7:35 ` Chao Yu 2026-04-26 9:30 ` Ruipeng Qi 1 sibling, 1 reply; 5+ messages in thread From: Chao Yu @ 2026-04-20 7:35 UTC (permalink / raw) To: ruipengqi, jaegeuk; +Cc: chao, linux-f2fs-devel, linux-kernel Hi Ruipeng, Sorry, I missed your patch. On 3/25/2026 9:37 PM, ruipengqi wrote: > From: Ruipeng Qi <ruipengqi3@gmail.com> > > 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 //0xfffffe0d6ca08300 > 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. > > To avoid this potential deadlock, always call f2fs_submit_merged_write > before triggering f2fs_gc in f2fs_balance_fs. > > Signed-off-by: Ruipeng Qi <ruipengqi3@gmail.com> > --- > fs/f2fs/segment.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 6a97fe76712b..b58299e49c23 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -454,6 +454,20 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) > io_schedule(); > finish_wait(&sbi->gc_thread->fggc_wq, &wait); > } else { > + > + /* > + * Before triggering foreground GC, submit all cached DATA > + * write bios. During writeback, pages may be added to > + * write_io[DATA].bio with PG_writeback set but the bio not > + * yet submitted. If GC's move_data_page() blocks on > + * __folio_lock() for such a folio, and the lock holder waits > + * for PG_writeback to clear via VFS folio_wait_writeback() > + * neither thread can make progress. Flushing here ensures > + * the bio completion callback can clear PG_writeback. > + */ > + > + f2fs_submit_merged_write(sbi, DATA); Do we need to call f2fs_submit_merged_ipu_write(sbi, bio, NULL) to commit cached IPU folios as well? Not sure, this race condition will happen for node folio. Thanks, > + > struct f2fs_gc_control gc_control = { > .victim_segno = NULL_SEGNO, > .init_gc_type = f2fs_sb_has_blkzoned(sbi) ? ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() 2026-04-20 7:35 ` Chao Yu @ 2026-04-26 9:30 ` Ruipeng Qi 2026-04-27 7:46 ` Chao Yu 0 siblings, 1 reply; 5+ messages in thread From: Ruipeng Qi @ 2026-04-26 9:30 UTC (permalink / raw) To: Chao Yu, jaegeuk; +Cc: linux-f2fs-devel, linux-kernel On 2026/4/20 15:35, Chao Yu wrote: > Hi Ruipeng, > > Sorry, I missed your patch. > > On 3/25/2026 9:37 PM, ruipengqi wrote: >> From: Ruipeng Qi <ruipengqi3@gmail.com> >> >> 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 //0xfffffe0d6ca08300 >> 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. >> >> To avoid this potential deadlock, always call f2fs_submit_merged_write >> before triggering f2fs_gc in f2fs_balance_fs. >> >> Signed-off-by: Ruipeng Qi <ruipengqi3@gmail.com> >> --- >> fs/f2fs/segment.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index 6a97fe76712b..b58299e49c23 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -454,6 +454,20 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, >> bool need) >> io_schedule(); >> finish_wait(&sbi->gc_thread->fggc_wq, &wait); >> } else { >> + >> + /* >> + * Before triggering foreground GC, submit all cached DATA >> + * write bios. During writeback, pages may be added to >> + * write_io[DATA].bio with PG_writeback set but the bio not >> + * yet submitted. If GC's move_data_page() blocks on >> + * __folio_lock() for such a folio, and the lock holder waits >> + * for PG_writeback to clear via VFS folio_wait_writeback() >> + * neither thread can make progress. Flushing here ensures >> + * the bio completion callback can clear PG_writeback. >> + */ >> + >> + f2fs_submit_merged_write(sbi, DATA); > > Do we need to call f2fs_submit_merged_ipu_write(sbi, bio, NULL) to commit > cached IPU folios as well? > > Not sure, this race condition will happen for node folio. > > Thanks, > Hi, Chao Thanks for your suggestion. After deeper analysis, this race condition applies to IPU folios but not node folios. Node folios are unlikely to have this flow. I will send a corrected version shortly. v2: - Commit cached OPU and IPU folios, not just OPU folios as in v1. BTW, Do you think it is possible to add an optional ->wait_folio_writeback() callback to address_space_operations. when provided, truncate_inode_partial_folio() calls f2fs_wait_on_page_writeback instead of the generic folio_wait_writeback(), which also fix this race condition. Thanks, >> + >> struct f2fs_gc_control gc_control = { >> .victim_segno = NULL_SEGNO, >> .init_gc_type = f2fs_sb_has_blkzoned(sbi) ? ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() 2026-04-26 9:30 ` Ruipeng Qi @ 2026-04-27 7:46 ` Chao Yu 0 siblings, 0 replies; 5+ messages in thread From: Chao Yu @ 2026-04-27 7:46 UTC (permalink / raw) To: Ruipeng Qi, jaegeuk; +Cc: chao, linux-f2fs-devel, linux-kernel On 4/26/26 17:30, Ruipeng Qi wrote: > > On 2026/4/20 15:35, Chao Yu wrote: >> Hi Ruipeng, >> >> Sorry, I missed your patch. >> >> On 3/25/2026 9:37 PM, ruipengqi wrote: >>> From: Ruipeng Qi <ruipengqi3@gmail.com> >>> >>> 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 //0xfffffe0d6ca08300 >>> 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. >>> >>> To avoid this potential deadlock, always call f2fs_submit_merged_write >>> before triggering f2fs_gc in f2fs_balance_fs. >>> >>> Signed-off-by: Ruipeng Qi <ruipengqi3@gmail.com> >>> --- >>> fs/f2fs/segment.c | 14 ++++++++++++++ >>> 1 file changed, 14 insertions(+) >>> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>> index 6a97fe76712b..b58299e49c23 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -454,6 +454,20 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) >>> io_schedule(); >>> finish_wait(&sbi->gc_thread->fggc_wq, &wait); >>> } else { >>> + >>> + /* >>> + * Before triggering foreground GC, submit all cached DATA >>> + * write bios. During writeback, pages may be added to >>> + * write_io[DATA].bio with PG_writeback set but the bio not >>> + * yet submitted. If GC's move_data_page() blocks on >>> + * __folio_lock() for such a folio, and the lock holder waits >>> + * for PG_writeback to clear via VFS folio_wait_writeback() >>> + * neither thread can make progress. Flushing here ensures >>> + * the bio completion callback can clear PG_writeback. >>> + */ >>> + >>> + f2fs_submit_merged_write(sbi, DATA); >> >> Do we need to call f2fs_submit_merged_ipu_write(sbi, bio, NULL) to commit >> cached IPU folios as well? >> >> Not sure, this race condition will happen for node folio. >> >> Thanks, >> > Hi, Chao > > Thanks for your suggestion. After deeper analysis, this race condition > applies to IPU folios but not node folios. Node folios are unlikely to > have this flow. Ruipeng, I agree, I don't see any flow calling truncate_inode_pages_range(node_inode) will race w/ writepage -> balance_fs. > > I will send a corrected version shortly. > v2: > - Commit cached OPU and IPU folios, not just OPU folios as in v1. > > BTW, Do you think it is possible to add an optional ->wait_folio_writeback() > callback to address_space_operations. when provided, > truncate_inode_partial_folio() calls f2fs_wait_on_page_writeback instead of > the generic folio_wait_writeback(), which also fix this race condition. Yes, I think it will be better as it can fix all potential wait_writeback bugs, I guess we can have a try. Thanks, > > Thanks, > >>> + >>> struct f2fs_gc_control gc_control = { >>> .victim_segno = NULL_SEGNO, >>> .init_gc_type = f2fs_sb_has_blkzoned(sbi) ? ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-04-27 7:46 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-03-25 13:37 [PATCH] f2fs: fix potential deadlock in f2fs_balance_fs() ruipengqi 2026-04-20 1:41 ` Ruipeng Qi 2026-04-20 7:35 ` Chao Yu 2026-04-26 9:30 ` Ruipeng Qi 2026-04-27 7:46 ` Chao Yu
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