[dm-devel] Re: [PATCH 2/3] Implement generic freeze feature

[Takashi Sato]

Hi,

>> -void thaw_bdev(struct block_device *bdev, struct super_block *sb)
>> +int thaw_bdev(struct block_device *bdev, struct super_block *sb)
>>  {
>> + int error = 0;
>> +
>> + mutex_lock(&bdev->bd_fsfreeze_mutex);
>> + if (!bdev->bd_fsfreeze_count) {
>> + mutex_unlock(&bdev->bd_fsfreeze_mutex);
>> + return -EINVAL;
> 
> This would be a programming error, yes?

This is not a kernel programming error but a user's.
thaw_bdev() is called via the unfreeze ioctl.  If a user calls the unfreeze
ioctl for an unfrozen filesystem, this error will be returned.
So a WARN_ON isn't needed.

> If so, a WARN_ON is more appropriate than a silent runtime error.
> 
>> + }

Cheers, Takashi