btrfs: do not return errors from raid56_parity_write

Always consume the bio and call the end_io handler on error instead of
returning an error and letting the caller handle it.  This matches what
the block layer submission does and avoids any confusion on who
needs to handle errors.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Tested-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -1803,18 +1803,19 @@ static void rbio_add_bio(struct btrfs_raid_bio *rbio, struct bio *orig_bio)
 /*
  * our main entry point for writes from the rest of the FS.
  */
-int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
+void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
 {
 	struct btrfs_fs_info *fs_info = bioc->fs_info;
 	struct btrfs_raid_bio *rbio;
 	struct btrfs_plug_cb *plug = NULL;
 	struct blk_plug_cb *cb;
-	int ret;
+	int ret = 0;
 
 	rbio = alloc_rbio(fs_info, bioc);
 	if (IS_ERR(rbio)) {
 		btrfs_put_bioc(bioc);
-		return PTR_ERR(rbio);
+		ret = PTR_ERR(rbio);
+		goto out;
 	}
 	rbio->operation = BTRFS_RBIO_WRITE;
 	rbio_add_bio(rbio, bio);
@@ -1829,8 +1830,8 @@ int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
 	if (rbio_is_full(rbio)) {
 		ret = full_stripe_write(rbio);
 		if (ret)
-			btrfs_bio_counter_dec(fs_info);
-		return ret;
+			goto out_dec_counter;
+		return;
 	}
 
 	cb = blk_check_plugged(btrfs_raid_unplug, fs_info, sizeof(*plug));
@@ -1841,13 +1842,19 @@ int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
 			INIT_LIST_HEAD(&plug->rbio_list);
 		}
 		list_add_tail(&rbio->plug_list, &plug->rbio_list);
-		ret = 0;
 	} else {
 		ret = __raid56_parity_write(rbio);
 		if (ret)
-			btrfs_bio_counter_dec(fs_info);
+			goto out_dec_counter;
 	}
-	return ret;
+
+	return;
+
+out_dec_counter:
+	btrfs_bio_counter_dec(fs_info);
+out:
+	bio->bi_status = errno_to_blk_status(ret);
+	bio_endio(bio);
 }
 
 /*

fs/btrfs/raid56.h

@@ -167,7 +167,7 @@ struct btrfs_device;
 
 int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 			  int mirror_num, int generic_io);
-int raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
+void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
 
 void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,
 			    unsigned int pgoff, u64 logical);

fs/btrfs/volumes.c

@@ -6762,7 +6762,7 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 	if ((bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
 	    ((btrfs_op(bio) == BTRFS_MAP_WRITE) || (mirror_num > 1))) {
 		if (btrfs_op(bio) == BTRFS_MAP_WRITE)
-			ret = raid56_parity_write(bio, bioc);
+			raid56_parity_write(bio, bioc);
 		else
 			ret = raid56_parity_recover(bio, bioc, mirror_num, 1);
 		goto out_dec;