Merge tag 'md/4.1-rc3-fixes' of git://neil.brown.name/md

Pull md bugfixes from Neil Brown:
 "A few fixes for md.

  Most of these are related to the new "batched stripe writeout", but
  there are a few others"

* tag 'md/4.1-rc3-fixes' of git://neil.brown.name/md:
  md/raid5: fix handling of degraded stripes in batches.
  md/raid5: fix allocation of 'scribble' array.
  md/raid5: don't record new size if resize_stripes fails.
  md/raid5: avoid reading parity blocks for full-stripe write to degraded array
  md/raid5: more incorrect BUG_ON in handle_stripe_fill.
  md/raid5: new alloc_stripe() to allocate an initialize a stripe.
  md-raid0: conditional mddev->queue access to suit dm-raid

2 files changed, 73 insertions, 55 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 2cb59a641cd244..6a68ef5246d499 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -188,8 +188,9 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 		}
 		dev[j] = rdev1;
 
-		disk_stack_limits(mddev->gendisk, rdev1->bdev,
-				  rdev1->data_offset << 9);
+		if (mddev->queue)
+			disk_stack_limits(mddev->gendisk, rdev1->bdev,
+					  rdev1->data_offset << 9);
 
 		if (rdev1->bdev->bd_disk->queue->merge_bvec_fn)
 			conf->has_merge_bvec = 1;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 77dfd720aaa00e..1ba97fdc6df1e3 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1078,9 +1078,6 @@ again:
 			pr_debug("skip op %ld on disc %d for sector %llu\n",
 				bi->bi_rw, i, (unsigned long long)sh->sector);
 			clear_bit(R5_LOCKED, &sh->dev[i].flags);
-			if (sh->batch_head)
-				set_bit(STRIPE_BATCH_ERR,
-					&sh->batch_head->state);
 			set_bit(STRIPE_HANDLE, &sh->state);
 		}
 
@@ -1971,17 +1968,30 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 	put_cpu();
 }
 
+static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp)
+{
+	struct stripe_head *sh;
+
+	sh = kmem_cache_zalloc(sc, gfp);
+	if (sh) {
+		spin_lock_init(&sh->stripe_lock);
+		spin_lock_init(&sh->batch_lock);
+		INIT_LIST_HEAD(&sh->batch_list);
+		INIT_LIST_HEAD(&sh->lru);
+		atomic_set(&sh->count, 1);
+	}
+	return sh;
+}
 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
 {
 	struct stripe_head *sh;
-	sh = kmem_cache_zalloc(conf->slab_cache, gfp);
+
+	sh = alloc_stripe(conf->slab_cache, gfp);
 	if (!sh)
 		return 0;
 
 	sh->raid_conf = conf;
 
-	spin_lock_init(&sh->stripe_lock);
-
 	if (grow_buffers(sh, gfp)) {
 		shrink_buffers(sh);
 		kmem_cache_free(conf->slab_cache, sh);
@@ -1990,13 +2000,8 @@ static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
 	sh->hash_lock_index =
 		conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
 	/* we just created an active stripe so... */
-	atomic_set(&sh->count, 1);
 	atomic_inc(&conf->active_stripes);
-	INIT_LIST_HEAD(&sh->lru);
 
-	spin_lock_init(&sh->batch_lock);
-	INIT_LIST_HEAD(&sh->batch_list);
-	sh->batch_head = NULL;
 	release_stripe(sh);
 	conf->max_nr_stripes++;
 	return 1;
@@ -2060,6 +2065,35 @@ static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
 	return ret;
 }
 
+static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
+{
+	unsigned long cpu;
+	int err = 0;
+
+	mddev_suspend(conf->mddev);
+	get_online_cpus();
+	for_each_present_cpu(cpu) {
+		struct raid5_percpu *percpu;
+		struct flex_array *scribble;
+
+		percpu = per_cpu_ptr(conf->percpu, cpu);
+		scribble = scribble_alloc(new_disks,
+					  new_sectors / STRIPE_SECTORS,
+					  GFP_NOIO);
+
+		if (scribble) {
+			flex_array_free(percpu->scribble);
+			percpu->scribble = scribble;
+		} else {
+			err = -ENOMEM;
+			break;
+		}
+	}
+	put_online_cpus();
+	mddev_resume(conf->mddev);
+	return err;
+}
+
 static int resize_stripes(struct r5conf *conf, int newsize)
 {
 	/* Make all the stripes able to hold 'newsize' devices.
@@ -2088,7 +2122,6 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 	struct stripe_head *osh, *nsh;
 	LIST_HEAD(newstripes);
 	struct disk_info *ndisks;
-	unsigned long cpu;
 	int err;
 	struct kmem_cache *sc;
 	int i;
@@ -2109,13 +2142,11 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 		return -ENOMEM;
 
 	for (i = conf->max_nr_stripes; i; i--) {
-		nsh = kmem_cache_zalloc(sc, GFP_KERNEL);
+		nsh = alloc_stripe(sc, GFP_KERNEL);
 		if (!nsh)
 			break;
 
 		nsh->raid_conf = conf;
-		spin_lock_init(&nsh->stripe_lock);
-
 		list_add(&nsh->lru, &newstripes);
 	}
 	if (i) {
@@ -2142,13 +2173,11 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 				    lock_device_hash_lock(conf, hash));
 		osh = get_free_stripe(conf, hash);
 		unlock_device_hash_lock(conf, hash);
-		atomic_set(&nsh->count, 1);
+
 		for(i=0; i<conf->pool_size; i++) {
 			nsh->dev[i].page = osh->dev[i].page;
 			nsh->dev[i].orig_page = osh->dev[i].page;
 		}
-		for( ; i<newsize; i++)
-			nsh->dev[i].page = NULL;
 		nsh->hash_lock_index = hash;
 		kmem_cache_free(conf->slab_cache, osh);
 		cnt++;
@@ -2174,25 +2203,6 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 	} else
 		err = -ENOMEM;
 
-	get_online_cpus();
-	for_each_present_cpu(cpu) {
-		struct raid5_percpu *percpu;
-		struct flex_array *scribble;
-
-		percpu = per_cpu_ptr(conf->percpu, cpu);
-		scribble = scribble_alloc(newsize, conf->chunk_sectors /
-			STRIPE_SECTORS, GFP_NOIO);
-
-		if (scribble) {
-			flex_array_free(percpu->scribble);
-			percpu->scribble = scribble;
-		} else {
-			err = -ENOMEM;
-			break;
-		}
-	}
-	put_online_cpus();
-
 	/* Step 4, return new stripes to service */
 	while(!list_empty(&newstripes)) {
 		nsh = list_entry(newstripes.next, struct stripe_head, lru);
@@ -2212,7 +2222,8 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 
 	conf->slab_cache = sc;
 	conf->active_name = 1-conf->active_name;
-	conf->pool_size = newsize;
+	if (!err)
+		conf->pool_size = newsize;
 	return err;
 }
 
@@ -2434,7 +2445,7 @@ static void raid5_end_write_request(struct bio *bi, int error)
 	}
 	rdev_dec_pending(rdev, conf->mddev);
 
-	if (sh->batch_head && !uptodate)
+	if (sh->batch_head && !uptodate && !replacement)
 		set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
 
 	if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
@@ -3278,7 +3289,9 @@ static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
 		/* reconstruct-write isn't being forced */
 		return 0;
 	for (i = 0; i < s->failed; i++) {
-		if (!test_bit(R5_UPTODATE, &fdev[i]->flags) &&
+		if (s->failed_num[i] != sh->pd_idx &&
+		    s->failed_num[i] != sh->qd_idx &&
+		    !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
 		    !test_bit(R5_OVERWRITE, &fdev[i]->flags))
 			return 1;
 	}
@@ -3298,6 +3311,7 @@ static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
 		 */
 		BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
 		BUG_ON(test_bit(R5_Wantread, &dev->flags));
+		BUG_ON(sh->batch_head);
 		if ((s->uptodate == disks - 1) &&
 		    (s->failed && (disk_idx == s->failed_num[0] ||
 				   disk_idx == s->failed_num[1]))) {
@@ -3366,7 +3380,6 @@ static void handle_stripe_fill(struct stripe_head *sh,
 {
 	int i;
 
-	BUG_ON(sh->batch_head);
 	/* look for blocks to read/compute, skip this if a compute
 	 * is already in flight, or if the stripe contents are in the
 	 * midst of changing due to a write
@@ -4198,15 +4211,9 @@ static void check_break_stripe_batch_list(struct stripe_head *sh)
 		return;
 
 	head_sh = sh;
-	do {
-		sh = list_first_entry(&sh->batch_list,
-				      struct stripe_head, batch_list);
-		BUG_ON(sh == head_sh);
-	} while (!test_bit(STRIPE_DEGRADED, &sh->state));
 
-	while (sh != head_sh) {
-		next = list_first_entry(&sh->batch_list,
-					struct stripe_head, batch_list);
+	list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
+
 		list_del_init(&sh->batch_list);
 
 		set_mask_bits(&sh->state, ~STRIPE_EXPAND_SYNC_FLAG,
@@ -4226,8 +4233,6 @@ static void check_break_stripe_batch_list(struct stripe_head *sh)
 
 		set_bit(STRIPE_HANDLE, &sh->state);
 		release_stripe(sh);
-
-		sh = next;
 	}
 }
 
@@ -6221,8 +6226,11 @@ static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu
 		percpu->spare_page = alloc_page(GFP_KERNEL);
 	if (!percpu->scribble)
 		percpu->scribble = scribble_alloc(max(conf->raid_disks,
-			conf->previous_raid_disks), conf->chunk_sectors /
-			STRIPE_SECTORS, GFP_KERNEL);
+						      conf->previous_raid_disks),
+						  max(conf->chunk_sectors,
+						      conf->prev_chunk_sectors)
+						   / STRIPE_SECTORS,
+						  GFP_KERNEL);
 
 	if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
 		free_scratch_buffer(conf, percpu);
@@ -7198,6 +7206,15 @@ static int check_reshape(struct mddev *mddev)
 	if (!check_stripe_cache(mddev))
 		return -ENOSPC;
 
+	if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
+	    mddev->delta_disks > 0)
+		if (resize_chunks(conf,
+				  conf->previous_raid_disks
+				  + max(0, mddev->delta_disks),
+				  max(mddev->new_chunk_sectors,
+				      mddev->chunk_sectors)
+			    ) < 0)
+			return -ENOMEM;
 	return resize_stripes(conf, (conf->previous_raid_disks
 				     + mddev->delta_disks));
 }