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466357dc9b
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.