Messages in this thread | | | Date | Mon, 28 Apr 2008 09:03:58 -0400 | From | Christoph Hellwig <> | Subject | Re: [RFC PATCH 1/3] Implement generic freeze feature |
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On Mon, Apr 28, 2008 at 09:59:55PM +0900, Takashi Sato wrote: >> I think the protection against double freezes would be better done by >> using a trylock on bd_mount_sem. > > 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.
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