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authorKazuya Mio <k-mio@sx.jp.nec.com>2011-12-01 16:51:07 +0900
committerBen Hutchings <ben@decadent.org.uk>2012-05-31 00:43:54 +0100
commit42bbdb289122169ec6d4f2a4bec848491c4408a7 (patch)
treeb36456b346cb3be18f8ed8f2a9b670faf86053e0
parentd2b6ee559fe72ec90da4eb623f3f01135c5a1ec7 (diff)
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 <k-mio@sx.jp.nec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--fs/super.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c
index afd0f1ad45e..2a698f6a3c2 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1166,6 +1166,8 @@ 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;
}