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DM RAID: Fix for "sync" directive ineffectiveness 

There are two table arguments that can be given to a DM RAID target
that control whether the array is forced to (re)synchronize or skip
initialization: "sync" and "nosync".  When "sync" is given, we set
mddev->recovery_cp to 0 in order to cause the device to resynchronize.
This is insufficient if there is a bitmap in use, because the array
will simply look at the bitmap and see that there is no recovery
necessary.

The fix is to skip over the loading of the superblocks when "sync" is
given, causing new superblocks to be written that will force the array
to go through initialization (i.e. synchronization).

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Jonathan Brassow 2012-10-11 13:42:19 +11:00 committed by NeilBrown
parent 7386199c47
commit 761becff01
1 changed files with 13 additions and 0 deletions
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13
drivers/md/dm-raid.c
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@ -1017,6 +1017,19 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
freshest = NULL;
rdev_for_each_safe(rdev, tmp, mddev) {
/*
* Skipping super_load due to DMPF_SYNC will cause
* the array to undergo initialization again as
* though it were new. This is the intended effect
* of the "sync" directive.
*
* When reshaping capability is added, we must ensure
* that the "sync" directive is disallowed during the
* reshape.
*/
if (rs->print_flags & DMPF_SYNC)
continue;
if (!rdev->meta_bdev)
continue;