From 32b268195c968892eec3cdb328e2594e379a658b Mon Sep 17 00:00:00 2001 From: Neil Brown Date: Thu, 23 Aug 2007 00:56:48 +0200 Subject: [PATCH] md: Allow re-add to work on array without bitmaps When an array has a bitmap, a device can be removed and re-added and only blocks changes since the removal (as recorded in the bitmap) will be resynced. It should be possible to do a similar thing to arrays without bitmaps. i.e. if a device is removed and re-added and *no* changes have been made in the interim, then the add should not require a resync. This patch allows that option. This means that when assembling an array one device at a time (e.g. during device discovery) the array can be enabled read-only as soon as enough devices are available, but extra devices can still be added without causing a resync. Signed-off-by: Neil Brown Signed-off-by: Adrian Bunk --- drivers/md/md.c | 25 ++++++++++++++----------- drivers/md/raid1.c | 6 ++++++ 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 22ca22c343c6..e0b81b607184 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -722,6 +722,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev) { mdp_disk_t *desc; mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page); + __u64 ev1 = md_event(sb); rdev->raid_disk = -1; rdev->flags = 0; @@ -738,7 +739,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev) mddev->layout = sb->layout; mddev->raid_disks = sb->raid_disks; mddev->size = sb->size; - mddev->events = md_event(sb); + mddev->events = ev1; mddev->bitmap_offset = 0; mddev->default_bitmap_offset = MD_SB_BYTES >> 9; @@ -773,7 +774,6 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev) } else if (mddev->pers == NULL) { /* Insist on good event counter while assembling */ - __u64 ev1 = md_event(sb); ++ev1; if (ev1 < mddev->events) return -EINVAL; @@ -781,11 +781,13 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev) /* if adding to array with a bitmap, then we can accept an * older device ... but not too old. */ - __u64 ev1 = md_event(sb); if (ev1 < mddev->bitmap->events_cleared) return 0; - } else /* just a hot-add of a new device, leave raid_disk at -1 */ - return 0; + } else { + if (ev1 < mddev->events) + /* just a hot-add of a new device, leave raid_disk at -1 */ + return 0; + } if (mddev->level != LEVEL_MULTIPATH) { desc = sb->disks + rdev->desc_nr; @@ -1067,6 +1069,7 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version) static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev) { struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page); + __u64 ev1 = le64_to_cpu(sb->events); rdev->raid_disk = -1; rdev->flags = 0; @@ -1082,7 +1085,7 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev) mddev->layout = le32_to_cpu(sb->layout); mddev->raid_disks = le32_to_cpu(sb->raid_disks); mddev->size = le64_to_cpu(sb->size)/2; - mddev->events = le64_to_cpu(sb->events); + mddev->events = ev1; mddev->bitmap_offset = 0; mddev->default_bitmap_offset = 1024 >> 9; @@ -1103,7 +1106,6 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev) } } else if (mddev->pers == NULL) { /* Insist of good event counter while assembling */ - __u64 ev1 = le64_to_cpu(sb->events); ++ev1; if (ev1 < mddev->events) return -EINVAL; @@ -1111,12 +1113,13 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev) /* If adding to array with a bitmap, then we can accept an * older device, but not too old. */ - __u64 ev1 = le64_to_cpu(sb->events); if (ev1 < mddev->bitmap->events_cleared) return 0; - } else /* just a hot-add of a new device, leave raid_disk at -1 */ - return 0; - + } else { + if (ev1 < mddev->events) + /* just a hot-add of a new device, leave raid_disk at -1 */ + return 0; + } if (mddev->level != LEVEL_MULTIPATH) { int role; rdev->desc_nr = le32_to_cpu(sb->dev_number); diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 0a01a0cbd88a..b8889200718b 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1630,6 +1630,12 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i /* before building a request, check if we can skip these blocks.. * This call the bitmap_start_sync doesn't actually record anything */ + if (mddev->bitmap == NULL && + mddev->recovery_cp == MaxSector && + conf->fullsync == 0) { + *skipped = 1; + return max_sector - sector_nr; + } if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) && !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { /* We can skip this block, and probably several more */ -- 2.39.5