diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b24d116eaf0b..f9091bd41e99 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1306,8 +1306,10 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 			 u64 num_bytes, u64 *actual_bytes)
 {
-	int ret;
+	int ret = 0;
 	u64 discarded_bytes = 0;
+	u64 end = bytenr + num_bytes;
+	u64 cur = bytenr;
 	struct btrfs_bio *bbio = NULL;
 
 
@@ -1316,15 +1318,23 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 	 * associated to its stripes that don't go away while we are discarding.
 	 */
 	btrfs_bio_counter_inc_blocked(fs_info);
-	/* Tell the block device(s) that the sectors can be discarded */
-	ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
-			      &bbio, 0);
-	/* Error condition is -ENOMEM */
-	if (!ret) {
-		struct btrfs_bio_stripe *stripe = bbio->stripes;
+	while (cur < end) {
+		struct btrfs_bio_stripe *stripe;
 		int i;
 
+		num_bytes = end - cur;
+		/* Tell the block device(s) that the sectors can be discarded */
+		ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, cur,
+				      &num_bytes, &bbio, 0);
+		/*
+		 * Error can be -ENOMEM, -ENOENT (no such chunk mapping) or
+		 * -EOPNOTSUPP. For any such error, @num_bytes is not updated,
+		 * thus we can't continue anyway.
+		 */
+		if (ret < 0)
+			goto out;
 
+		stripe = bbio->stripes;
 		for (i = 0; i < bbio->num_stripes; i++, stripe++) {
 			u64 bytes;
 			struct request_queue *req_q;
@@ -1341,10 +1351,19 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 						  stripe->physical,
 						  stripe->length,
 						  &bytes);
-			if (!ret)
+			if (!ret) {
 				discarded_bytes += bytes;
-			else if (ret != -EOPNOTSUPP)
-				break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
+			} else if (ret != -EOPNOTSUPP) {
+				/*
+				 * Logic errors or -ENOMEM, or -EIO, but
+				 * unlikely to happen.
+				 *
+				 * And since there are two loops, explicitly
+				 * go to out to avoid confusion.
+				 */
+				btrfs_put_bbio(bbio);
+				goto out;
+			}
 
 			/*
 			 * Just in case we get back EOPNOTSUPP for some reason,
@@ -1354,7 +1373,9 @@ int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
 			ret = 0;
 		}
 		btrfs_put_bbio(bbio);
+		cur += num_bytes;
 	}
+out:
 	btrfs_bio_counter_dec(fs_info);
 
 	if (actual_bytes)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 6a0288d17b7d..e6c458d99722 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5374,12 +5374,13 @@ void btrfs_put_bbio(struct btrfs_bio *bbio)
  * replace.
  */
 static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
-					 u64 logical, u64 length,
+					 u64 logical, u64 *length_ret,
 					 struct btrfs_bio **bbio_ret)
 {
 	struct extent_map *em;
 	struct map_lookup *map;
 	struct btrfs_bio *bbio;
+	u64 length = *length_ret;
 	u64 offset;
 	u64 stripe_nr;
 	u64 stripe_nr_end;
@@ -5413,6 +5414,7 @@ static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
 
 	offset = logical - em->start;
 	length = min_t(u64, em->start + em->len - logical, length);
+	*length_ret = length;
 
 	stripe_len = map->stripe_len;
 	/*
@@ -5827,7 +5829,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
 
 	if (op == BTRFS_MAP_DISCARD)
 		return __btrfs_map_block_for_discard(fs_info, logical,
-						     *length, bbio_ret);
+						     length, bbio_ret);
 
 	ret = btrfs_get_io_geometry(fs_info, op, logical, *length, &geom);
 	if (ret < 0)