btrfs: raid56: simplify code flow in rmw_rbio

Remove the write goto label by moving the data page allocation and data
read into the branch.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -2300,12 +2300,10 @@ static int rmw_rbio(struct btrfs_raid_bio *rbio)
 	 * Either full stripe write, or we have every data sector already
 	 * cached, can go to write path immediately.
 	 */
-	if (rbio_is_full(rbio) || !need_read_stripe_sectors(rbio))
-		goto write;
-
+	if (!rbio_is_full(rbio) && need_read_stripe_sectors(rbio)) {
 		/*
-	 * Now we're doing sub-stripe write, also need all data stripes to do
-	 * the full RMW.
+		 * Now we're doing sub-stripe write, also need all data stripes
+		 * to do the full RMW.
 		 */
 		ret = alloc_rbio_data_pages(rbio);
 		if (ret < 0)
@@ -2316,8 +2314,8 @@ static int rmw_rbio(struct btrfs_raid_bio *rbio)
 		ret = rmw_read_wait_recover(rbio);
 		if (ret < 0)
 			return ret;
+	}
 
-write:
 	/*
 	 * At this stage we're not allowed to add any new bios to the
 	 * bio list any more, anyone else that wants to change this stripe