Date: Wed, 18 Sep 2013 20:33:20 GMT From: dennis chang <dchang@panasas.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/182214: vop_stdfsync() incorrectly retries too many times Message-ID: <201309182033.r8IKXKwO048401@oldred.freebsd.org> Resent-Message-ID: <201309182040.r8IKe07n089338@freefall.freebsd.org>
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>Number: 182214
>Category: kern
>Synopsis: vop_stdfsync() incorrectly retries too many times
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Sep 18 20:40:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator: dennis chang
>Release: 7.2 and 10
>Organization:
panasas
>Environment:
>Description:
687 /*
688 * If synchronous the caller expects us to completely resolve all
689 * dirty buffers in the system. Wait for in-progress I/O to
690 * complete (which could include background bitmap writes), then
691 * retry if dirty blocks still exist.
692 */
693 if (ap->a_waitfor == MNT_WAIT) {
694 bufobj_wwait(bo, 0, 0);
695 if (bo->bo_dirty.bv_cnt > 0) {
696 /*
697 * If we are unable to write any of these buffers
698 * then we fail now rather than trying endlessly
699 * to write them out.
700 */
701 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
702 if ((error = bp->b_error) == 0) ---> error is constantly overwritten. It should bail out when any buffer has an error.
703 continue;
704 if (error == 0 && --maxretry >= 0) ----> error is from the last buffer, instead of any buffer.
705 goto loop1;
706 error = EAGAIN;
707 }
708 }
>How-To-Repeat:
>Fix:
687 /*
688 * If synchronous the caller expects us to completely resolve all
689 * dirty buffers in the system. Wait for in-progress I/O to
690 * complete (which could include background bitmap writes), then
691 * retry if dirty blocks still exist.
692 */
693 if (ap->a_waitfor == MNT_WAIT) {
694 bufobj_wwait(bo, 0, 0);
695 if (bo->bo_dirty.bv_cnt > 0) {
696 /*
697 * If we are unable to write any of these buffers
698 * then we fail now rather than trying endlessly
699 * to write them out.
700 */
701 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
702 if (bp->b_error)
703 error = b_error;
break;
}
}
704 if (error == 0 && --maxretry >= 0)
705 goto loop1;
706 error = EAGAIN;
707 }
708 }
>Release-Note:
>Audit-Trail:
>Unformatted:
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