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author | Chao Yu <yuchao0@huawei.com> | 2020-03-20 13:14:31 +0300 |
---|---|---|
committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-03-31 06:46:23 +0300 |
commit | 466357dc9b5ff555d16b7f9a0ff264eb9d5d908b (patch) | |
tree | 3a070c8627316525782c3b0ec727b7a93b651187 /fs | |
parent | ad8d6a02d685ecf046c369d72285a5e69adaf66e (diff) | |
download | linux-466357dc9b5ff555d16b7f9a0ff264eb9d5d908b.tar.xz |
f2fs: fix potential deadlock on compressed quota file
generic/232 reports below deadlock:
fsstress D 0 96980 96969 0x00084000
Call Trace:
schedule+0x4a/0xb0
io_schedule+0x12/0x40
__lock_page+0x127/0x1d0
pagecache_get_page+0x1d8/0x250
prepare_compress_overwrite+0xe0/0x490 [f2fs]
f2fs_prepare_compress_overwrite+0x5d/0x80 [f2fs]
f2fs_write_begin+0x833/0xb90 [f2fs]
f2fs_quota_write+0x145/0x1e0 [f2fs]
write_blk+0x36/0x80 [quota_tree]
do_insert_tree+0x2ac/0x4a0 [quota_tree]
do_insert_tree+0x26e/0x4a0 [quota_tree]
qtree_write_dquot+0x70/0x190 [quota_tree]
v2_write_dquot+0x43/0x90 [quota_v2]
dquot_acquire+0x77/0x100
f2fs_dquot_acquire+0x2f/0x60 [f2fs]
dqget+0x310/0x450
dquot_transfer+0xb2/0x120
f2fs_setattr+0x11a/0x4a0 [f2fs]
notify_change+0x349/0x480
chown_common+0x168/0x1c0
do_fchownat+0xbc/0xf0
__x64_sys_lchown+0x21/0x30
do_syscall_64+0x5f/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
task PC stack pid father
kworker/u256:0 D 0 103444 2 0x80084000
Workqueue: writeback wb_workfn (flush-251:1)
Call Trace:
schedule+0x4a/0xb0
schedule_timeout+0x15e/0x2f0
io_schedule_timeout+0x19/0x40
congestion_wait+0x7e/0x120
f2fs_write_multi_pages+0x12a/0x840 [f2fs]
f2fs_write_cache_pages+0x48f/0x790 [f2fs]
f2fs_write_data_pages+0x2db/0x330 [f2fs]
do_writepages+0x1a/0x60
__writeback_single_inode+0x3d/0x340
writeback_sb_inodes+0x225/0x4a0
wb_writeback+0xf7/0x320
wb_workfn+0xba/0x470
process_one_work+0x16c/0x3f0
worker_thread+0x4c/0x440
kthread+0xf8/0x130
ret_from_fork+0x35/0x40
fsstress D 0 5277 5266 0x00084000
Call Trace:
schedule+0x4a/0xb0
rwsem_down_write_slowpath+0x29d/0x540
block_operations+0x105/0x360 [f2fs]
f2fs_write_checkpoint+0x101/0x1010 [f2fs]
f2fs_sync_fs+0xa8/0x130 [f2fs]
f2fs_do_sync_file+0x1ad/0x890 [f2fs]
do_fsync+0x38/0x60
__x64_sys_fdatasync+0x13/0x20
do_syscall_64+0x5f/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The root cause is there is potential deadlock between quota data
update and writeback.
Kworker Thread B Thread C
- f2fs_write_cache_pages
- lock whole cluster --- A
- f2fs_write_multi_pages
- f2fs_write_raw_pages
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_setattr
- f2fs_lock_op --- B
- f2fs_write_checkpoint
- block_operations
- f2fs_lock_all --- B
- dquot_transfer
- f2fs_quota_write
- f2fs_prepare_compress_overwrite
- pagecache_get_page --- A
- f2fs_trylock_op failed --- B
- congestion_wait
- goto rewrite
To fix this issue, during quota file writeback, just redirty all pages
left in cluster rather holding pages' lock in cluster and looping retrying
lock cp_rwsem.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/f2fs/compress.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index f9cf75fe4a12..00fd6f904139 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -1002,6 +1002,15 @@ retry_write: unlock_page(cc->rpages[i]); ret = 0; } else if (ret == -EAGAIN) { + /* + * for quota file, just redirty left pages to + * avoid deadlock caused by cluster update race + * from foreground operation. + */ + if (IS_NOQUOTA(cc->inode)) { + err = 0; + goto out_err; + } ret = 0; cond_resched(); congestion_wait(BLK_RW_ASYNC, @@ -1011,16 +1020,12 @@ retry_write: goto retry_write; } err = ret; - goto out_fail; + goto out_err; } *submitted += _submitted; } return 0; - -out_fail: - /* TODO: revoke partially updated block addresses */ - BUG_ON(compr_blocks); out_err: for (++i; i < cc->cluster_size; i++) { if (!cc->rpages[i]) |