linux-stable.git/drivers/md/raid5.c, branch v3.4

md/raid5: Fix a bug about judging if the operation is syncing or replacing

2012-04-03T05:37:38+00:00

When create a raid5 using assume-clean and echo check or repair to
sync_action.Then component disks did not operated IO but the raid
check/resync faster than normal.
Because the judgement in function analyse_stripe():
		if (do_recovery ||
		    sh->sector >= conf->mddev->recovery_cp)
			s->syncing = 1;
		else
			s->replacing = 1;
When check or repair,the recovery_cp == MaxSectore,so syncing equal zero
not one.

This bug was introduced by commit 9a3e1101b827
    md/raid5:  detect and handle replacements during recovery.
so this patch is suitable for 3.3-stable.

Cc: stable@vger.kernel.org
Signed-off-by: majianpeng 
Signed-off-by: NeilBrown

md/raid5: fix handling of bad blocks during recovery.

2012-04-03T05:36:17+00:00

1/ We can only treat a known-bad-block like a read-error if we
   have the data that belongs in that block.  So fix that test.

2/ If we cannot recovery a stripe due to insufficient data,
   don't tell "md_done_sync" that the sync failed unless we really
   did fail something.  If we successfully record bad blocks,
   that is success.

Reported-by: "majianpeng" 
Signed-off-by: NeilBrown

md: tidy up rdev_for_each usage.

2012-03-19T01:46:39+00:00

md.h has an 'rdev_for_each()' macro for iterating the rdevs in an
mddev.  However it uses the 'safe' version of list_for_each_entry,
and so requires the extra variable, but doesn't include 'safe' in the
name, which is useful documentation.

Consequently some places use this safe version without needing it, and
many use an explicity list_for_each entry.

So:
 - rename rdev_for_each to rdev_for_each_safe
 - create a new rdev_for_each which uses the plain
   list_for_each_entry,
 - use the 'safe' version only where needed, and convert all other
   list_for_each_entry calls to use rdev_for_each.

Signed-off-by: NeilBrown

md: allow re-add to failed arrays.

2012-03-19T01:46:37+00:00

When an array is failed (some data inaccessible) then there is no
point attempting to add a spare as it could not possibly be recovered.

However that may be value in re-adding a recently removed device.
e.g. if there is a write-intent-bitmap and it is clear, then access
to the data could be restored by this action.

So don't reject a re-add to a failed array for RAID10 and RAID5 (the
only arrays  types that check for a failed array).

Signed-off-by: NeilBrown

md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read().

2012-03-13T00:21:25+00:00

Signed-off-by: majianpeng 
Signed-off-by: NeilBrown

md/raid5: removed unused 'added_devices' variable.

2012-03-13T00:21:21+00:00

commit 908f4fbd265733 removed the last user of this variable,
so we should discard it completely.

Signed-off-by: NeilBrown

md/raid5: make sure reshape_position is cleared on error path.

2012-03-13T00:21:18+00:00

Leaving a valid reshape_position value in place could be confusing.

Signed-off-by: NeilBrown

md/raid5: Mark device want_replacement when we see a write error.

2011-12-22T23:17:54+00:00

Now that WantReplacement drives are replaced cleanly, mark a drive
as WantReplacement when we see a write error.  It might get failed soon so
the WantReplacement flag is irrelevant, but if the write error is recorded
in the bad block log, we still want to activate any spare that might
be available.

Reviewed-by: Dan Williams 
Signed-off-by:  NeilBrown

md/raid5: If there is a spare and a want_replacement device, start replacement.

2011-12-22T23:17:53+00:00

When attempting to add a spare to a RAID[456] array, also consider
adding it as a replacement for a want_replacement device.

This requires that common md code attempt hot_add even when the array
is not formally degraded.

Reviewed-by: Dan Williams 
Signed-off-by: NeilBrown

md/raid5: recognise replacements when assembling array.

2011-12-22T23:17:53+00:00

If a Replacement is seen, file it as such.

If we see two replacements (or two normal devices) for the one slot,
abort.

Reviewed-by: Dan Williams 
Signed-off-by: NeilBrown