From b098636cf04c89db4036fedc778da0acc666ad1a Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 11 May 2011 15:52:21 +1000 Subject: [PATCH] md: allow resync_start to be set while an array is active. The sysfs attribute 'resync_start' (known internally as recovery_cp), records where a resync is up to. A value of 0 means the array is not known to be in-sync at all. A value of MaxSector means the array is believed to be fully in-sync. When the size of member devices of an array (RAID1,RAID4/5/6) is increased, the array can be increased to match. This process sets resync_start to the old end-of-device offset so that the new part of the array gets resynced. However with RAID1 (and RAID6) a resync is not technically necessary and may be undesirable. So it would be good if the implied resync after the array is resized could be avoided. So: change 'resync_start' so the value can be changed while the array is active, and as a precaution only allow it to be changed while resync/recovery is 'frozen'. Changing it once resync has started is not going to be useful anyway. This allows the array to be resized without a resync by: write 'frozen' to 'sync_action' write new size to 'component_size' (this will set resync_start) write 'none' to 'resync_start' write 'idle' to 'sync_action'. Also slightly improve some tests on recovery_cp when resizing raid1/raid5. Now that an arbitrary value could be set we should be more careful in our tests. Signed-off-by: NeilBrown --- drivers/md/md.c | 2 +- drivers/md/raid1.c | 2 +- drivers/md/raid5.c | 3 ++- 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 5469ae35ee15..aa640a85bb21 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3324,7 +3324,7 @@ resync_start_store(mddev_t *mddev, const char *buf, size_t len) char *e; unsigned long long n = simple_strtoull(buf, &e, 10); - if (mddev->pers) + if (mddev->pers && !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)) return -EBUSY; if (cmd_match(buf, "none")) n = MaxSector; diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 779abbd2bb1d..5d096096f958 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2061,7 +2061,7 @@ static int raid1_resize(mddev_t *mddev, sector_t sectors) set_capacity(mddev->gendisk, mddev->array_sectors); revalidate_disk(mddev->gendisk); if (sectors > mddev->dev_sectors && - mddev->recovery_cp == MaxSector) { + mddev->recovery_cp > mddev->dev_sectors) { mddev->recovery_cp = mddev->dev_sectors; set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); } diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 51af7f3bfe52..34dd54539f7b 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5389,7 +5389,8 @@ static int raid5_resize(mddev_t *mddev, sector_t sectors) return -EINVAL; set_capacity(mddev->gendisk, mddev->array_sectors); revalidate_disk(mddev->gendisk); - if (sectors > mddev->dev_sectors && mddev->recovery_cp == MaxSector) { + if (sectors > mddev->dev_sectors && + mddev->recovery_cp > mddev->dev_sectors) { mddev->recovery_cp = mddev->dev_sectors; set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); }