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Bug #4238

krbd: still more barrier fixes

Added by Alex Elder over 7 years ago. Updated over 7 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Target version:
% Done:

0%

Source:
Development
Tags:
Backport:
Regression:
No
Severity:
3 - minor
Reviewed:
Affected Versions:
ceph-qa-suite:
Pull request ID:
Crash signature:

Description

While looking at http://tracker.ceph.com/issues/4079 I
concluded that the fix I put in for this might still
not be right:
07741308 rbd: add barriers near done flag operations

Fix it, and use full memory barriers to be conservative
about it and be done with this issue once and for all.

History

#1 Updated by Alex Elder over 7 years ago

  • Status changed from In Progress to Fix Under Review
  • Target version set to v0.58

Posted for review.

commit 5ba6ae1682d395087cf854dc7dd8a4c72419b47b
Author: Alex Elder <elder@inktank.com>
Date:   Thu Feb 21 10:10:06 2013 -0600

    rbd: barriers are hard

    Let's go shopping!

    I'm afraid this may not have gotten it right:
        07741308  rbd: add barriers near done flag operations

    The smp_wmb() should have been done *before* setting the done flag,
    to ensure all other data was valid before marking the object request
    done.

    Switch to use atomic_inc_return() here to set the done flag, which
    allows us to verify we don't mark something done more than once.
    Doing this also implies general barriers before and after the call.

    And although a read memory barrier might have been sufficient before
    reading the done flag, convert this to a full memory barrier just
    to put this issue to bed.

    This resolves:
        http://tracker.ceph.com/issues/4238

    Signed-off-by: Alex Elder <elder@inktank.com>

#2 Updated by Alex Elder over 7 years ago

  • Status changed from Fix Under Review to Resolved

This has been committed.

commit 632b88cadece050ca925d74bda250c4a320c5cc7
Author: Alex Elder <>
Date: Thu Feb 21 10:10:06 2013 -0600

rbd: barriers are hard

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