lkml.org 
[lkml]   [2010]   [Jun]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/5] fsfreeze: Prevent emergency thaw from looping infinitely
On Thu, Jun 10, 2010 at 05:19:50PM +1000, Dave Chinner wrote:
> Return -EINVAL when the filesystem is already unfrozen to avoid this
> problem.


This includes some additional changes in addition to the description,
and at least one of them seems incorrect.

> - error = 0;
> - if (--bdev->bd_fsfreeze_count > 0)
> + if (!sb)
> goto out;
>
> - if (!sb)
> + error = 0;
> + if (--bdev->bd_fsfreeze_count > 0)
> goto out;

Here you reorder the sb check to be before the counter decrement. But
we do support calling freeze_bdev on a device without a superblock, and
you would leak bd_fsfreeze_count for that case and wrongly return
-EINVAL on unthaw for these now.

> error = thaw_super(sb);
> - if (error) {
> + if (error)
> bdev->bd_fsfreeze_count++;
> - mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return error;
> - }

Ok, useful cleanup.

> out:
> mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return 0;
> + return error;

And this is the actual fix of course, also looks good.



\
 
 \ /
  Last update: 2010-06-14 17:21    [W:0.297 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site