Messages in this thread Patch in this message | | | Date | Fri, 18 May 2012 14:16:47 -0700 | From | Greg KH <> | Subject | [ 48/54] wake up s_wait_unfrozen when ->freeze_fs fails |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Kazuya Mio <k-mio@sx.jp.nec.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/super.c | 2 ++ 1 file changed, 2 insertions(+)
--- 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; }
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