From fcb2c2e95085336d1d6ac9cc1a07a783f80e60c0 Mon Sep 17 00:00:00 2001 From: Kazuya Mio Date: Thu, 1 Dec 2011 16:51:07 +0900 Subject: wake up s_wait_unfrozen when ->freeze_fs fails commit e1616300a20c80396109c1cf013ba9a36055a3da upstream. dd slept infinitely when fsfeeze failed because of EIO. To fix this problem, if ->freeze_fs fails, freeze_super() wakes up the tasks waiting for the filesystem to become unfrozen. When s_frozen isn't SB_UNFROZEN in __generic_file_aio_write(), the function sleeps until FITHAW ioctl wakes up s_wait_unfrozen. However, if ->freeze_fs fails, s_frozen is set to SB_UNFROZEN and then freeze_super() returns an error number. In this case, FITHAW ioctl returns EINVAL because s_frozen is already SB_UNFROZEN. There is no way to wake up s_wait_unfrozen, so __generic_file_aio_write() sleeps infinitely. Signed-off-by: Kazuya Mio Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/super.c b/fs/super.c index ab3d672..caf4dfa 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1009,6 +1009,8 @@ int freeze_super(struct super_block *sb) printk(KERN_ERR "VFS:Filesystem freeze failed\n"); sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); deactivate_locked_super(sb); return ret; } -- cgit v1.1