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>

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 8c928cd72b61..4665bff1bf55 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2843,8 +2843,7 @@ static inline bool is_valid_data_blkaddr(struct f2fs_sb_info *sbi,
  */
 int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync);
 void f2fs_truncate_data_blocks(struct dnode_of_data *dn);
-int f2fs_truncate_blocks(struct inode *inode, u64 from, bool lock,
-							bool buf_write);
+int f2fs_truncate_blocks(struct inode *inode, u64 from, bool lock);
 int f2fs_truncate(struct inode *inode);
 int f2fs_getattr(const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int flags);