f2fs: fix potential data inconsistence of checkpoint
Previously, we changed lock from cp_rwsem to node_change, it solved
the deadlock issue which was caused by below race condition:
Thread A Thread B
- f2fs_setattr
- f2fs_lock_op -- read_lock
- dquot_transfer
- __dquot_transfer
- dquot_acquire
- commit_dqblk
- f2fs_quota_write
- f2fs_write_begin
- f2fs_write_failed
- write_checkpoint
- block_operations
- f2fs_lock_all -- write_lock
- f2fs_truncate_blocks
- f2fs_lock_op -- read_lock
But it breaks the sematics of cp_rwsem, in other callers like:
- f2fs_file_write_iter -> f2fs_write_begin -> f2fs_write_failed
- f2fs_direct_IO -> f2fs_write_failed
We allow to truncate dnode w/o cp_rwsem held, result in incorrect sit
bitmap update, which can cause further data corruption.
So this patch reverts previous fix implementation, and try to fix
deadlock by skipping calling f2fs_truncate_blocks() in f2fs_write_failed()
only for quota file, and keep the preallocated data/node in the tail of
quota file, we can expecte that the preallocated space can be used to
store quota info latter soon.
Fixes: af033b2aa8a8 ("f2fs: guarantee journalled quota data by checkpoint")
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
4 files changed