kmem_cache_t *sc;
int devs = conf->raid_disks;
- sprintf(conf->cache_name, "raid5/%s", mdname(conf->mddev));
-
- sc = kmem_cache_create(conf->cache_name,
+ sprintf(conf->cache_name[0], "raid5/%s", mdname(conf->mddev));
+ sprintf(conf->cache_name[1], "raid5/%s-alt", mdname(conf->mddev));
+ conf->active_name = 0;
+ sc = kmem_cache_create(conf->cache_name[conf->active_name],
sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
0, 0, NULL, NULL);
if (!sc)
return 1;
conf->slab_cache = sc;
+ conf->pool_size = devs;
while (num--) {
if (!grow_one_stripe(conf))
return 1;
}
return 0;
}
+static int resize_stripes(raid5_conf_t *conf, int newsize)
+{
+ /* Make all the stripes able to hold 'newsize' devices.
+ * New slots in each stripe get 'page' set to a new page.
+ *
+ * This happens in stages:
+ * 1/ create a new kmem_cache and allocate the required number of
+ * stripe_heads.
+ * 2/ gather all the old stripe_heads and tranfer the pages across
+ * to the new stripe_heads. This will have the side effect of
+ * freezing the array as once all stripe_heads have been collected,
+ * no IO will be possible. Old stripe heads are freed once their
+ * pages have been transferred over, and the old kmem_cache is
+ * freed when all stripes are done.
+ * 3/ reallocate conf->disks to be suitable bigger. If this fails,
+ * we simple return a failre status - no need to clean anything up.
+ * 4/ allocate new pages for the new slots in the new stripe_heads.
+ * If this fails, we don't bother trying the shrink the
+ * stripe_heads down again, we just leave them as they are.
+ * As each stripe_head is processed the new one is released into
+ * active service.
+ *
+ * Once step2 is started, we cannot afford to wait for a write,
+ * so we use GFP_NOIO allocations.
+ */
+ struct stripe_head *osh, *nsh;
+ LIST_HEAD(newstripes);
+ struct disk_info *ndisks;
+ int err = 0;
+ kmem_cache_t *sc;
+ int i;
+
+ if (newsize <= conf->pool_size)
+ return 0; /* never bother to shrink */
+
+ /* Step 1 */
+ sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
+ sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
+ 0, 0, NULL, NULL);
+ if (!sc)
+ return -ENOMEM;
+
+ for (i = conf->max_nr_stripes; i; i--) {
+ nsh = kmem_cache_alloc(sc, GFP_KERNEL);
+ if (!nsh)
+ break;
+
+ memset(nsh, 0, sizeof(*nsh) + (newsize-1)*sizeof(struct r5dev));
+
+ nsh->raid_conf = conf;
+ spin_lock_init(&nsh->lock);
+
+ list_add(&nsh->lru, &newstripes);
+ }
+ if (i) {
+ /* didn't get enough, give up */
+ while (!list_empty(&newstripes)) {
+ nsh = list_entry(newstripes.next, struct stripe_head, lru);
+ list_del(&nsh->lru);
+ kmem_cache_free(sc, nsh);
+ }
+ kmem_cache_destroy(sc);
+ return -ENOMEM;
+ }
+ /* Step 2 - Must use GFP_NOIO now.
+ * OK, we have enough stripes, start collecting inactive
+ * stripes and copying them over
+ */
+ list_for_each_entry(nsh, &newstripes, lru) {
+ spin_lock_irq(&conf->device_lock);
+ wait_event_lock_irq(conf->wait_for_stripe,
+ !list_empty(&conf->inactive_list),
+ conf->device_lock,
+ unplug_slaves(conf->mddev);
+ );
+ osh = get_free_stripe(conf);
+ spin_unlock_irq(&conf->device_lock);
+ atomic_set(&nsh->count, 1);
+ for(i=0; i<conf->pool_size; i++)
+ nsh->dev[i].page = osh->dev[i].page;
+ for( ; i<newsize; i++)
+ nsh->dev[i].page = NULL;
+ kmem_cache_free(conf->slab_cache, osh);
+ }
+ kmem_cache_destroy(conf->slab_cache);
+
+ /* Step 3.
+ * At this point, we are holding all the stripes so the array
+ * is completely stalled, so now is a good time to resize
+ * conf->disks.
+ */
+ ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
+ if (ndisks) {
+ for (i=0; i<conf->raid_disks; i++)
+ ndisks[i] = conf->disks[i];
+ kfree(conf->disks);
+ conf->disks = ndisks;
+ } else
+ err = -ENOMEM;
+
+ /* Step 4, return new stripes to service */
+ while(!list_empty(&newstripes)) {
+ nsh = list_entry(newstripes.next, struct stripe_head, lru);
+ list_del_init(&nsh->lru);
+ for (i=conf->raid_disks; i < newsize; i++)
+ if (nsh->dev[i].page == NULL) {
+ struct page *p = alloc_page(GFP_NOIO);
+ nsh->dev[i].page = p;
+ if (!p)
+ err = -ENOMEM;
+ }
+ release_stripe(nsh);
+ }
+ /* critical section pass, GFP_NOIO no longer needed */
+
+ conf->slab_cache = sc;
+ conf->active_name = 1-conf->active_name;
+ conf->pool_size = newsize;
+ return err;
+}
+
static int drop_one_stripe(raid5_conf_t *conf)
{
return 0;
if (atomic_read(&sh->count))
BUG();
- shrink_buffers(sh, conf->raid_disks);
+ shrink_buffers(sh, conf->pool_size);
kmem_cache_free(conf->slab_cache, sh);
atomic_dec(&conf->active_stripes);
return 1;
projects / linux-beck.git / blobdiff