[PATCH] md: optimise reconstruction when re-adding a recently failed drive.
When an array is degraded, bit in the intent-bitmap are never cleared. So if
a recently failed drive is re-added, we only need to reconstruct the block
that are still reflected in the bitmap.
This patch adds support for this re-adding.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c3b4772..3f5234f 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -811,9 +811,12 @@
{
conf_t *conf = mddev->private;
int found = 0;
- int mirror;
+ int mirror = 0;
mirror_info_t *p;
+ if (rdev->saved_raid_disk >= 0 &&
+ conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
+ mirror = rdev->saved_raid_disk;
for (mirror=0; mirror < mddev->raid_disks; mirror++)
if ( !(p=conf->mirrors+mirror)->rdev) {
@@ -830,6 +833,8 @@
p->head_position = 0;
rdev->raid_disk = mirror;
found = 1;
+ if (rdev->saved_raid_disk != mirror)
+ conf->fullsync = 1;
p->rdev = rdev;
break;
}
