The following commit has been merged in the linux branch: commit 5e5e3e78ed9038b8f7112835d07084eefb9daa47 Author: NeilBrown neilb@suse.de Date: Fri Oct 16 16:35:30 2009 +1100

md: Fix handling of raid5 array which is being reshaped to fewer devices.

When a raid5 (or raid6) array is being reshaped to have fewer devices, conf->raid_disks is the latter and hence smaller number of devices. However sometimes we want to use a number which is the total number of currently required devices - the larger of the 'old' and 'new' sizes. Before we implemented reducing the number of devices, this was always 'new' i.e. ->raid_disks. Now we need max(raid_disks, previous_raid_disks) in those places.

This particularly affects assembling an array that was shutdown while in the middle of a reshape to fewer devices.

md.c needs a similar fix when interpreting the md metadata.

Signed-off-by: NeilBrown neilb@suse.de

diff --git a/drivers/md/md.c b/drivers/md/md.c index 26ba42a..10eb1fc 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2631,7 +2631,7 @@ static void analyze_sbs(mddev_t * mddev) rdev->desc_nr = i++; rdev->raid_disk = rdev->desc_nr; set_bit(In_sync, &rdev->flags); - } else if (rdev->raid_disk >= mddev->raid_disks) { + } else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) { rdev->raid_disk = -1; clear_bit(In_sync, &rdev->flags); } diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index d4ce51b..c4366c9 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -1238,22 +1238,22 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) static int grow_one_stripe(raid5_conf_t *conf) { struct stripe_head *sh; + int disks = max(conf->raid_disks, conf->previous_raid_disks); sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL); if (!sh) return 0; - memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev)); + memset(sh, 0, sizeof(*sh) + (disks-1)*sizeof(struct r5dev)); sh->raid_conf = conf; spin_lock_init(&sh->lock); #ifdef CONFIG_MULTICORE_RAID456 init_waitqueue_head(&sh->ops.wait_for_ops); #endif

- if (grow_buffers(sh, conf->raid_disks)) { - shrink_buffers(sh, conf->raid_disks); + if (grow_buffers(sh, disks)) { + shrink_buffers(sh, disks); kmem_cache_free(conf->slab_cache, sh); return 0; } - sh->disks = conf->raid_disks; /* we just created an active stripe so... */ atomic_set(&sh->count, 1); atomic_inc(&conf->active_stripes); @@ -1265,7 +1265,7 @@ static int grow_one_stripe(raid5_conf_t *conf) static int grow_stripes(raid5_conf_t *conf, int num) { struct kmem_cache *sc; - int devs = conf->raid_disks; + int devs = max(conf->raid_disks, conf->previous_raid_disks);

sprintf(conf->cache_name[0], "raid%d-%s", conf->level, mdname(conf->mddev)); @@ -3540,9 +3540,10 @@ static void unplug_slaves(mddev_t *mddev) { raid5_conf_t *conf = mddev->private; int i; + int devs = max(conf->raid_disks, conf->previous_raid_disks);

rcu_read_lock(); - for (i = 0; i < conf->raid_disks; i++) { + for (i = 0; i < devs; i++) { mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) { struct request_queue *r_queue = bdev_get_queue(rdev->bdev); @@ -4562,13 +4563,9 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)

if (!sectors) sectors = mddev->dev_sectors; - if (!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; - } + raid_disks = min(conf->raid_disks, conf->previous_raid_disks);

sectors &= ~((sector_t)mddev->chunk_sectors - 1); sectors &= ~((sector_t)mddev->new_chunk_sectors - 1); @@ -4669,7 +4666,7 @@ static int raid5_alloc_percpu(raid5_conf_t *conf) } per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page; } - scribble = kmalloc(scribble_len(conf->raid_disks), GFP_KERNEL); + scribble = kmalloc(conf->scribble_len, GFP_KERNEL); if (!scribble) { err = -ENOMEM; break; @@ -4690,7 +4687,7 @@ static int raid5_alloc_percpu(raid5_conf_t *conf) static raid5_conf_t *setup_conf(mddev_t *mddev) { raid5_conf_t *conf; - int raid_disk, memory; + int raid_disk, memory, max_disks; mdk_rdev_t *rdev; struct disk_info *disk;

@@ -4740,13 +4737,14 @@ static raid5_conf_t *setup_conf(mddev_t *mddev) conf->bypass_threshold = BYPASS_THRESHOLD;

conf->raid_disks = mddev->raid_disks; - conf->scribble_len = scribble_len(conf->raid_disks); if (mddev->reshape_position == MaxSector) conf->previous_raid_disks = mddev->raid_disks; else conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks; + max_disks = max(conf->raid_disks, conf->previous_raid_disks); + conf->scribble_len = scribble_len(max_disks);

- conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info), + conf->disks = kzalloc(max_disks * sizeof(struct disk_info), GFP_KERNEL); if (!conf->disks) goto abort; @@ -4764,7 +4762,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)

list_for_each_entry(rdev, &mddev->disks, same_set) { raid_disk = rdev->raid_disk; - if (raid_disk >= conf->raid_disks + if (raid_disk >= max_disks || raid_disk < 0) continue; disk = conf->disks + raid_disk; @@ -4796,7 +4794,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev) }

memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + - conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; + max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; if (grow_stripes(conf, conf->max_nr_stripes)) { printk(KERN_ERR "raid5: couldn't allocate %dkB for buffers\n", memory); @@ -4921,7 +4919,8 @@ static int run(mddev_t *mddev) test_bit(In_sync, &rdev->flags)) working_disks++;

- mddev->degraded = conf->raid_disks - working_disks; + mddev->degraded = (max(conf->raid_disks, conf->previous_raid_disks) + - working_disks);

if (mddev->degraded > conf->max_degraded) { printk(KERN_ERR "raid5: not enough operational devices for %s"