Commit 7ec05478 authored Mar 31, 2009 by NeilBrown

md/raid5: enhance raid5_size to work correctly with negative delta_disks



This is the first of four patches which combine to allow md/raid5 to
reduce the number of devices in the array by restriping the data over
a subset of the devices.

If the number of disks in a raid4/5/6 is being reduced, then the
default size must be based on the new number, not the old number
of devices.
In general, it should be based on the smaller of new and old.

Signed-off-by: NeilBrown <neilb@suse.de>

parent 34e04e87

drivers/md/raid5.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -4169,8 +4169,13 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)

		if (!sectors)
		sectors = mddev->dev_sectors;
		if (!raid_disks)
		if (!raid_disks) {
		/* size is defined by the smallest of previous and new size */
		if (conf->raid_disks < conf->previous_raid_disks)
		raid_disks = conf->raid_disks;
		else
		raid_disks = conf->previous_raid_disks;
		}

		sectors &= ~((sector_t)mddev->chunk_size/512 - 1);
		return sectors * (raid_disks - conf->max_degraded);

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