On 9/13/12 6:03 AM, Fernando Luis Vázquez Cao wrote:
> The thawing of a filesystem through sysrq-j loops infinitely as it
> incorrectly detects a thawed filesytsem as frozen and tries to
> unfreeze repeatedly. This is a regression caused by
> 4504230a71566785a05d3e6b53fa1ee071b864eb ("freeze_bdev: grab active
> reference to frozen superblocks") in that it no longer returned
> -EINVAL for superblocks that were not frozen.
>
> Return -EINVAL when the filesystem is already unfrozen to avoid this
> problem.
>
> Cc: Josef Bacik <jbacik@xxxxxxxxxxxx>
> Cc: Eric Sandeen <sandeen@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Signed-off-by: Fernando Luis Vazquez Cao <fernando@xxxxxxxxxxxxx>
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
I actually sent a simpler (but less cleaned up) version of this 2 years ago,
I guess it got missed and I didn't notice. So thanks!
-Eric
> ---
>
> diff -urNp vfs-orig/fs/block_dev.c vfs/fs/block_dev.c
> --- vfs-orig/fs/block_dev.c 2012-07-04 18:57:54.000000000 +0900
> +++ vfs/fs/block_dev.c 2012-07-12 13:22:38.124815295 +0900
> @@ -319,22 +319,17 @@ int thaw_bdev(struct block_device *bdev,
> if (!bdev->bd_fsfreeze_count)
> goto out;
>
> - error = 0;
> - if (--bdev->bd_fsfreeze_count > 0)
> - goto out;
> -
> - if (!sb)
> + if (--bdev->bd_fsfreeze_count > 0 || !sb) {
> + error = 0;
> goto out;
> + }
>
> error = thaw_super(sb);
> - if (error) {
> + if (error)
> bdev->bd_fsfreeze_count++;
> - mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return error;
> - }
> out:
> mutex_unlock(&bdev->bd_fsfreeze_mutex);
> - return 0;
> + return error;
> }
> EXPORT_SYMBOL(thaw_bdev);
>
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
