Merge tag 'dm-4.4-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Five stable fixes:

   - Two DM btree bufio buffer leak fixes that resolve reported BUG_ONs
     during DM thinp metadata close's dm_bufio_client_destroy().

   - A DM thinp range discard fix to handle discarding a partially
     mapped range.

   - A DM thinp metadata snapshot fix to make sure the btree roots saved
     in the metadata snapshot are the most current.

   - A DM space map metadata refcounting fix that improves both DM thinp
     and DM cache metadata"

* tag 'dm-4.4-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm btree: fix bufio buffer leaks in dm_btree_del() error path
  dm space map metadata: fix ref counting bug when bootstrapping a new space map
  dm thin metadata: fix bug when taking a metadata snapshot
  dm thin metadata: fix bug in dm_thin_remove_range()
  dm btree: fix leak of bufio-backed block in btree_split_sibling error path

drivers/md/dm-thin-metadata.c

@@ -1206,6 +1206,12 @@ static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
 	struct dm_block *copy, *sblock;
 	dm_block_t held_root;
 
+	/*
+	 * We commit to ensure the btree roots which we increment in a
+	 * moment are up to date.
+	 */
+	__commit_transaction(pmd);
+
 	/*
 	 * Copy the superblock.
 	 */
@@ -1538,7 +1544,7 @@ static int __remove(struct dm_thin_device *td, dm_block_t block)
 static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)
 {
 	int r;
-	unsigned count;
+	unsigned count, total_count = 0;
 	struct dm_pool_metadata *pmd = td->pmd;
 	dm_block_t keys[1] = { td->id };
 	__le64 value;
@@ -1561,11 +1567,29 @@ static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_
 	if (r)
 		return r;
 
+	/*
+	 * Remove leaves stops at the first unmapped entry, so we have to
+	 * loop round finding mapped ranges.
+	 */
+	while (begin < end) {
+		r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);
+		if (r == -ENODATA)
+			break;
+
+		if (r)
+			return r;
+
+		if (begin >= end)
+			break;
+
 		r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);
 		if (r)
 			return r;
 
-	td->mapped_blocks -= count;
+		total_count += count;
+	}
+
+	td->mapped_blocks -= total_count;
 	td->changed = 1;
 
 	/*

drivers/md/persistent-data/dm-btree.c

@@ -63,6 +63,11 @@ int lower_bound(struct btree_node *n, uint64_t key)
 	return bsearch(n, key, 0);
 }
 
+static int upper_bound(struct btree_node *n, uint64_t key)
+{
+	return bsearch(n, key, 1);
+}
+
 void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
 		  struct dm_btree_value_type *vt)
 {
@@ -252,6 +257,16 @@ static void pop_frame(struct del_stack *s)
 	dm_tm_unlock(s->tm, f->b);
 }
 
+static void unlock_all_frames(struct del_stack *s)
+{
+	struct frame *f;
+
+	while (unprocessed_frames(s)) {
+		f = s->spine + s->top--;
+		dm_tm_unlock(s->tm, f->b);
+	}
+}
+
 int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 {
 	int r;
@@ -308,9 +323,13 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
 			pop_frame(s);
 		}
 	}
-
 out:
+	if (r) {
+		/* cleanup all frames of del_stack */
+		unlock_all_frames(s);
+	}
 	kfree(s);
+
 	return r;
 }
 EXPORT_SYMBOL_GPL(dm_btree_del);
@@ -392,6 +411,82 @@ int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
 }
 EXPORT_SYMBOL_GPL(dm_btree_lookup);
 
+static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,
+				       uint64_t key, uint64_t *rkey, void *value_le)
+{
+	int r, i;
+	uint32_t flags, nr_entries;
+	struct dm_block *node;
+	struct btree_node *n;
+
+	r = bn_read_lock(info, root, &node);
+	if (r)
+		return r;
+
+	n = dm_block_data(node);
+	flags = le32_to_cpu(n->header.flags);
+	nr_entries = le32_to_cpu(n->header.nr_entries);
+
+	if (flags & INTERNAL_NODE) {
+		i = lower_bound(n, key);
+		if (i < 0 || i >= nr_entries) {
+			r = -ENODATA;
+			goto out;
+		}
+
+		r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
+		if (r == -ENODATA && i < (nr_entries - 1)) {
+			i++;
+			r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);
+		}
+
+	} else {
+		i = upper_bound(n, key);
+		if (i < 0 || i >= nr_entries) {
+			r = -ENODATA;
+			goto out;
+		}
+
+		*rkey = le64_to_cpu(n->keys[i]);
+		memcpy(value_le, value_ptr(n, i), info->value_type.size);
+	}
+out:
+	dm_tm_unlock(info->tm, node);
+	return r;
+}
+
+int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
+			 uint64_t *keys, uint64_t *rkey, void *value_le)
+{
+	unsigned level;
+	int r = -ENODATA;
+	__le64 internal_value_le;
+	struct ro_spine spine;
+
+	init_ro_spine(&spine, info);
+	for (level = 0; level < info->levels - 1u; level++) {
+		r = btree_lookup_raw(&spine, root, keys[level],
+				     lower_bound, rkey,
+				     &internal_value_le, sizeof(uint64_t));
+		if (r)
+			goto out;
+
+		if (*rkey != keys[level]) {
+			r = -ENODATA;
+			goto out;
+		}
+
+		root = le64_to_cpu(internal_value_le);
+	}
+
+	r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);
+out:
+	exit_ro_spine(&spine);
+	return r;
+}
+
+EXPORT_SYMBOL_GPL(dm_btree_lookup_next);
+
 /*
  * Splits a node by creating a sibling node and shifting half the nodes
  * contents across.  Assumes there is a parent node, and it has room for
@@ -473,8 +568,10 @@ static int btree_split_sibling(struct shadow_spine *s, unsigned parent_index,
 
 	r = insert_at(sizeof(__le64), pn, parent_index + 1,
 		      le64_to_cpu(rn->keys[0]), &location);
-	if (r)
+	if (r) {
+		unlock_block(s->info, right);
 		return r;
+	}
 
 	if (key < le64_to_cpu(rn->keys[0])) {
 		unlock_block(s->info, right);

drivers/md/persistent-data/dm-btree.h

@@ -109,6 +109,13 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root);
 int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
 		    uint64_t *keys, void *value_le);
 
+/*
+ * Tries to find the first key where the bottom level key is >= to that
+ * given.  Useful for skipping empty sections of the btree.
+ */
+int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,
+			 uint64_t *keys, uint64_t *rkey, void *value_le);
+
 /*
  * Insertion (or overwrite an existing value).  O(ln(n))
  */
@@ -135,9 +142,10 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,
 		    uint64_t *keys, dm_block_t *new_root);
 
 /*
- * Removes values between 'keys' and keys2, where keys2 is keys with the
- * final key replaced with 'end_key'.  'end_key' is the one-past-the-end
- * value.  'keys' may be altered.
+ * Removes a _contiguous_ run of values starting from 'keys' and not
+ * reaching keys2 (where keys2 is keys with the final key replaced with
+ * 'end_key').  'end_key' is the one-past-the-end value.  'keys' may be
+ * altered.
  */
 int dm_btree_remove_leaves(struct dm_btree_info *info, dm_block_t root,
 			   uint64_t *keys, uint64_t end_key,

drivers/md/persistent-data/dm-space-map-metadata.c

@@ -136,7 +136,7 @@ static int brb_push(struct bop_ring_buffer *brb,
 	return 0;
 }
 
-static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
+static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
 {
 	struct block_op *bop;
 
@@ -147,6 +147,17 @@ static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
 	result->type = bop->type;
 	result->block = bop->block;
 
+	return 0;
+}
+
+static int brb_pop(struct bop_ring_buffer *brb)
+{
+	struct block_op *bop;
+
+	if (brb_empty(brb))
+		return -ENODATA;
+
+	bop = brb->bops + brb->begin;
 	brb->begin = brb_next(brb, brb->begin);
 
 	return 0;
@@ -211,7 +222,7 @@ static int apply_bops(struct sm_metadata *smm)
 	while (!brb_empty(&smm->uncommitted)) {
 		struct block_op bop;
 
-		r = brb_pop(&smm->uncommitted, &bop);
+		r = brb_peek(&smm->uncommitted, &bop);
 		if (r) {
 			DMERR("bug in bop ring buffer");
 			break;
@@ -220,6 +231,8 @@ static int apply_bops(struct sm_metadata *smm)
 		r = commit_bop(smm, &bop);
 		if (r)
 			break;
+
+		brb_pop(&smm->uncommitted);
 	}
 
 	return r;
@@ -683,7 +696,6 @@ static struct dm_space_map bootstrap_ops = {
 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 {
 	int r, i;
-	enum allocation_event ev;
 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 	dm_block_t old_len = smm->ll.nr_blocks;
 
@@ -705,11 +717,12 @@ static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 	 * allocate any new blocks.
 	 */
 	do {
-		for (i = old_len; !r && i < smm->begin; i++) {
-			r = sm_ll_inc(&smm->ll, i, &ev);
+		for (i = old_len; !r && i < smm->begin; i++)
+			r = add_bop(smm, BOP_INC, i);
+
 		if (r)
 			goto out;
-		}
+
 		old_len = smm->begin;
 
 		r = apply_bops(smm);
@@ -754,7 +767,6 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
 {
 	int r;
 	dm_block_t i;
-	enum allocation_event ev;
 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
 
 	smm->begin = superblock + 1;
@@ -782,7 +794,7 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
 	 * allocated blocks that they were built from.
 	 */
 	for (i = superblock; !r && i < smm->begin; i++)
-		r = sm_ll_inc(&smm->ll, i, &ev);
+		r = add_bop(smm, BOP_INC, i);
 
 	if (r)
 		return r;