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authorNeilBrown <neilb@suse.de>2009-03-31 15:10:36 +1100
committerNeilBrown <neilb@suse.de>2009-03-31 15:10:36 +1100
commit7ec0547838976d088dfb9cb0adb073e6e8a15aa3 (patch)
tree32f2d5aa5d112e99bebbfb9bfde49ba82b66809d /drivers
parent34e04e87fb8b2c62c9e8868f41c8179d0e15f51a (diff)
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/raid5.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3930b3e9aa0..5694eb8941b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4169,8 +4169,13 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
if (!sectors)
sectors = mddev->dev_sectors;
- if (!raid_disks)
- raid_disks = conf->previous_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);