From: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
To: Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org, tmb@mandriva.org
Cc: Fran?ois Figarola <francois.figarola@i-consult.fr>,
device-mapper development <dm-devel@redhat.com>,
Neil Brown <neilb@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-raid@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
stable@kernel.org
Subject: [BUGFIX] [PATCH] freeze_bdev: don't deactivate successfully frozen MS_RDONLY sb
Date: Fri, 29 Jan 2010 09:56:22 +0900 [thread overview]
Message-ID: <4B623236.90003@ce.jp.nec.com> (raw)
In-Reply-To: <20100128182528.GA29926@infradead.org>
Thanks Thomas and Christoph for testing and review.
I removed 'smp_wmb()' before up_write from the previous patch,
since up_write() should have necessary ordering constraints.
(I.e. the change of s_frozen is visible to others after up_write)
I'm quite sure the change is harmless but if you are uncomfortable
with Tested-by/Reviewed-by on the modified patch, please remove them.
If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of
deactivate_locked_super().
Also, keep sb->s_frozen consistent so that remount can check the frozen state.
Otherwise a crash reported here can happen:
http://lkml.org/lkml/2010/1/16/37
http://lkml.org/lkml/2010/1/28/53
This patch should be applied for 2.6.32 stable series, too.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@kernel.org
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 73d6a73..d11d028 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -246,7 +246,8 @@ struct super_block *freeze_bdev(struct block_device *bdev)
if (!sb)
goto out;
if (sb->s_flags & MS_RDONLY) {
- deactivate_locked_super(sb);
+ sb->s_frozen = SB_FREEZE_TRANS;
+ up_write(&sb->s_umount);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb;
}
@@ -307,7 +308,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
BUG_ON(sb->s_bdev != bdev);
down_write(&sb->s_umount);
if (sb->s_flags & MS_RDONLY)
- goto out_deactivate;
+ goto out_unfrozen;
if (sb->s_op->unfreeze_fs) {
error = sb->s_op->unfreeze_fs(sb);
@@ -321,11 +322,11 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
}
}
+out_unfrozen:
sb->s_frozen = SB_UNFROZEN;
smp_wmb();
wake_up(&sb->s_wait_unfrozen);
-out_deactivate:
if (sb)
deactivate_locked_super(sb);
out_unlock:
next prev parent reply other threads:[~2010-01-29 1:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-16 9:58 [BUG] kernel 2.6.32.x hangs during boot process François Figarola
2010-01-23 0:07 ` Andrew Morton
2010-01-28 2:42 ` Neil Brown
2010-01-28 6:32 ` [dm-devel] " Jun'ichi Nomura
2010-01-28 18:16 ` Thomas Backlund
2010-01-28 18:25 ` Christoph Hellwig
2010-01-29 0:56 ` Jun'ichi Nomura [this message]
2010-01-30 18:44 ` [BUGFIX] [PATCH] freeze_bdev: don't deactivate successfully frozen MS_RDONLY sb Thomas Backlund
2010-01-29 7:06 ` [dm-devel] [BUG] kernel 2.6.32.x hangs during boot process François Figarola
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4B623236.90003@ce.jp.nec.com \
--to=j-nomura@ce.jp.nec.com \
--cc=akpm@linux-foundation.org \
--cc=dm-devel@redhat.com \
--cc=francois.figarola@i-consult.fr \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-raid@vger.kernel.org \
--cc=neilb@suse.de \
--cc=stable@kernel.org \
--cc=tmb@mandriva.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).