[dm-devel] Re: [RFC PATCH 1/3] Implement generic freeze feature

[Takashi Sato]

Hi,

>> bd_mount_sem can protect against only freezes and cannot protect against
>> unfreezes.  If multiple unfreezes run in parallel,  the multiple up() for
>> bd_mount_sem might occur incorrectly.
>
> Indeed.  The bit flag would fix that because unfreeze could then check
> for the bit beeing set first.  So that's probably the easiest way to go.

I think the bit flag is more efficient than the semaphore.
So I will consider whether it can be used for the freeze feature.

Cheers, Takashi