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

From: Alasdair G Kergon
Date: Tue Nov 07 2006 - 18:35:21 EST


On Tue, Nov 07, 2006 at 03:18:08PM -0500, Mike Snitzer wrote:
> Srinivasa's description of the patch just speaks to how freeze_bdev
> and thaw_bdev are used by DM but completely skips justification for
> switching from mutex to semaphore. Why is it beneficial and/or
> necessary to use a semaphore instead of a mutex here?

This used to be a semaphore; someone changed it to a mutex; we started
getting device-mapper bug reports from people because the usage breaks the
stated semantics for a mutex; this patch puts things back while we consider
if there's a better way of doing things.

Alasdair
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agk@xxxxxxxxxx
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