From: Kazuya Mio <k-mio@sx.jp.nec.com>
Date: Thu, 1 Dec 2011 07:51:07 +0000 (+0900)
Subject: wake up s_wait_unfrozen when ->freeze_fs fails
X-Git-Tag: v3.3-rc1~3^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e1616300a20c80396109c1cf013ba9a36055a3da;p=pandora-kernel.git

wake up s_wait_unfrozen when ->freeze_fs fails

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>
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