vfs: fix unconditional write_super() call in file_fsync()

We need to check ->s_dirt before calling write_super().  It became the cause
of an unneeded write.

This bug was noticed by Sudhanshu Saxena.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
OGAWA Hirofumi 2008-04-29 00:59:42 -07:00 committed by Linus Torvalds
parent 8f0cfa52a1
commit 762873c251

View file

@ -64,7 +64,7 @@ int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
/* sync the superblock to buffers */
sb = inode->i_sb;
lock_super(sb);
if (sb->s_op->write_super)
if (sb->s_dirt && sb->s_op->write_super)
sb->s_op->write_super(sb);
unlock_super(sb);