From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Thornber <thornber@redhat.com>
Subject: Re: [PATCH] dm-bufio
Date: Mon, 17 Oct 2011 12:14:43 +0100
Message-ID: <20111017111442.GG13963@ubuntu>
References: <Pine.LNX.4.64.1110141500160.29246@hs20-bc2-1.build.redhat.com>
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To: Mikulas Patocka <mpatocka@redhat.com>
Cc: dm-devel@redhat.com, Mike Snitzer <msnitzer@redhat.com>, "Alasdair G. Kergon" <agk@redhat.com>
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On Fri, Oct 14, 2011 at 03:14:34PM -0400, Mikulas Patocka wrote:
@@ -999,15 +1013,19 @@ again:
                 * someone is doing some writes simultaneously with us --- in
                 * this case, stop dropping the lock.
                 */
                if (dropped_lock)
                        goto again;
        }
        wake_up(&c->free_buffer_wait);
        dm_bufio_unlock(c);

-       a = xchg(&c->async_write_error, 0);
+       if (likely(!c->async_write_error))
+               a = 0;
+       else
+               a = xchg(&c->async_write_error, 0);
        f = dm_bufio_issue_flush(c);


I didn't change this.  Is it also fixing a preexisting issue?