Btrfs: fix memory leak in raid56

The local bio_list may have pending bios when doing cleanup, it can
end up with memory leak if they don't get freed.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -1326,6 +1326,9 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
 
 cleanup:
 	rbio_orig_end_io(rbio, BLK_STS_IOERR);
+
+	while ((bio = bio_list_pop(&bio_list)))
+		bio_put(bio);
 }
 
 /*
@@ -1582,6 +1585,10 @@ static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
 
 cleanup:
 	rbio_orig_end_io(rbio, BLK_STS_IOERR);
+
+	while ((bio = bio_list_pop(&bio_list)))
+		bio_put(bio);
+
 	return -EIO;
 
 finish:
@@ -2107,6 +2114,10 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
 	if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
 	    rbio->operation == BTRFS_RBIO_REBUILD_MISSING)
 		rbio_orig_end_io(rbio, BLK_STS_IOERR);
+
+	while ((bio = bio_list_pop(&bio_list)))
+		bio_put(bio);
+
 	return -EIO;
 }
 
@@ -2460,6 +2471,9 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 
 cleanup:
 	rbio_orig_end_io(rbio, BLK_STS_IOERR);
+
+	while ((bio = bio_list_pop(&bio_list)))
+		bio_put(bio);
 }
 
 static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
@@ -2569,12 +2583,12 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
 	int stripe;
 	struct bio *bio;
 
+	bio_list_init(&bio_list);
+
 	ret = alloc_rbio_essential_pages(rbio);
 	if (ret)
 		goto cleanup;
 
-	bio_list_init(&bio_list);
-
 	atomic_set(&rbio->error, 0);
 	/*
 	 * build a list of bios to read all the missing parts of this
@@ -2642,6 +2656,10 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
 
 cleanup:
 	rbio_orig_end_io(rbio, BLK_STS_IOERR);
+
+	while ((bio = bio_list_pop(&bio_list)))
+		bio_put(bio);
+
 	return;
 
 finish: