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From: malahal@us.ibm.com
To: dm-devel@redhat.com
Subject: Re: [PATCH] a deadlock bug in the kernel-side device mapper code
Date: Fri, 6 Nov 2009 09:27:38 -0800	[thread overview]
Message-ID: <20091106172738.GA9738@us.ibm.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0911052157170.18661@hs20-bc2-1.build.redhat.com>

Mikulas Patocka [mpatocka@redhat.com] wrote:
> This patch introduces a new lock, _name_read_lock, that is placed around
> regions that modify pointer to the hash with dm_set_mdptr or that modify
> hc->name or hc->uuid. When this lock is taken, the caller can safely read
> the name and uuid.
> 
> This lock has much smaller span than _hash_lock and thus lock recursion
> can't happen.

This lock actually guarantees that hash cell, name (and uuid) don't
disappear when someone holds this lock. How about naming it to something
like _hashcell_name_uuid_lock()???

Thanks, Malahal.

  parent reply	other threads:[~2009-11-06 17:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-05 13:21 a deadlock bug in the kernel-side device mapper code guy keren
2009-11-05 14:24 ` Alasdair G Kergon
2009-11-06  2:58   ` [PATCH] " Mikulas Patocka
     [not found]     ` <20091106151504.GS13375@agk-dp.fab.redhat.com>
2009-11-06 16:30       ` Mikulas Patocka
2009-11-06 17:27     ` malahal [this message]
2009-11-09  8:51     ` Mike Anderson
2009-11-09 17:57       ` malahal
2009-11-09 22:24         ` malahal
2009-11-10  0:24         ` Alasdair G Kergon
2009-11-10  1:50           ` malahal
2009-11-10  5:24             ` Mike Anderson
2009-11-10  6:13       ` Mikulas Patocka
2009-11-06  0:24 ` Kiyoshi Ueda

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