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  1. 14 Dec, 2009 6 commits
    • NeilBrown's avatar
      md: support barrier requests on all personalities. · a2826aa9
      NeilBrown authored 
      Previously barriers were only supported on RAID1.  This is because
other levels requires synchronisation across all devices and so needed
a different approach.
Here is that approach.

When a barrier arrives, we send a zero-length barrier to every active
device.  When that completes - and if the original request was not
empty -  we submit the barrier request itself (with the barrier flag
cleared) and then submit a fresh load of zero length barriers.

The barrier request itself is asynchronous, but any subsequent
request will block until the barrier completes.

The reason for clearing the barrier flag is that a barrier request is
allowed to fail.  If we pass a non-empty barrier through a striping
raid level it is conceivable that part of it could succeed and part
could fail.  That would be way too hard to deal with.
So if the first run of zero length barriers succeed, we assume all is
sufficiently well that we send the request and ignore errors in the
second run of barriers.

RAID5 needs extra care as write requests may not have been submitted
to the underlying devices yet.  So we flush the stripe cache before
proceeding with the barrier.

Note that the second set of zero-length barriers are submitted
immediately after the original request is submitted.  Thus when
a personality finds mddev->barrier to be set during make_request,
it should not return from make_request until the corresponding
per-device request(s) have been queued.

That will be done in later patches.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarAndre Noll <maan@systemlinux.org>
      a2826aa9
    • NeilBrown's avatar
      md: don't reset curr_resync_completed after an interrupted resync · efa59339
      NeilBrown authored 
      If a resync/recovery/check/repair is interrupted for some reason, it
can be useful to know exactly where it got up to.
So in that case, do not clear curr_resync_completed.
Initialise it when starting a resync/recovery/... instead.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      efa59339
    • NeilBrown's avatar
      md: adjust resync_min usefully when resync aborts. · c07b70ad
      NeilBrown authored 
      When a 'check' or 'repair' finished we should clear resync_min
so that a future check/repair will cover the whole array (by default).
However if it is interrupted, we should update resync_min to
where we got up to, so that when the check/repair continues it
just does the remainder of the array.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      c07b70ad
    • NeilBrown's avatar
      md: remove sparse warning:symbol XXX was not declared. · 7820f9e1
      NeilBrown authored 
      Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      7820f9e1
    • NeilBrown's avatar
      md/raid5: remove some sparse warnings. · 8553fe7e
      NeilBrown authored 
      qd_idx is previously declared and given exactly the same value!
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      8553fe7e
    • NeilBrown's avatar
      md/bitmap: protect against bitmap removal while being updated. · aa5cbd10
      NeilBrown authored 
      A write intent bitmap can be removed from an array while the
array is active.
When this happens, all IO is suspended and flushed before the
bitmap is removed.
However it is possible that bitmap_daemon_work is still running to
clear old bits from the bitmap.  If it is, it can dereference the
bitmap after it has been freed.

So introduce a new mutex to protect bitmap_daemon_work and get it
before destroying a bitmap.

This is suitable for any current -stable kernel.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Cc: stable@kernel.org
      aa5cbd10
  3. 12 Dec, 2009 34 commits
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