[md PATCH 2/6] md/raid5: enhance raid5_size to work correctly with negative delta_disks
From: NeilBrown <hidden>
Date: 2009-03-24 08:53:32
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
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 <redacted> --- drivers/md/raid5.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3b71f01..74e89c1 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);