[dm-devel] Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex

[Eric Sandeen]

Andrew Morton wrote:

>> --- linux-2.6.19-rc4.orig/fs/buffer.c	2006-11-07 17:06:20.000000000 +0000
>> +++ linux-2.6.19-rc4/fs/buffer.c	2006-11-07 17:26:04.000000000 +0000
>> @@ -188,7 +188,9 @@ struct super_block *freeze_bdev(struct b
>>  {
>>  	struct super_block *sb;
>>  
>> -	mutex_lock(&bdev->bd_mount_mutex);
>> +	if (down_trylock(&bdev->bd_mount_sem))
>> +		return -EBUSY;
>> +
> 
> This is a functional change which isn't described in the changelog.  What's
> happening here?

Only allow one bdev-freezer in at a time, rather than queueing them up?

-Eric