btrfs: pass a block_device to btrfs_bio_clone

Pass the block_device to bio_alloc_clone instead of setting it later.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -3192,13 +3192,13 @@ struct bio *btrfs_bio_alloc(unsigned int nr_iovecs)
 	return bio;
 }
 
-struct bio *btrfs_bio_clone(struct bio *bio)
+struct bio *btrfs_bio_clone(struct block_device *bdev, struct bio *bio)
 {
 	struct btrfs_bio *bbio;
 	struct bio *new;
 
 	/* Bio allocation backed by a bioset does not fail */
-	new = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOFS, &btrfs_bioset);
+	new = bio_alloc_clone(bdev, bio, GFP_NOFS, &btrfs_bioset);
 	bbio = btrfs_bio(new);
 	btrfs_bio_init(bbio);
 	bbio->iter = bio->bi_iter;

fs/btrfs/extent_io.h

@@ -280,7 +280,7 @@ void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
 
 int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array);
 struct bio *btrfs_bio_alloc(unsigned int nr_iovecs);
-struct bio *btrfs_bio_clone(struct bio *bio);
+struct bio *btrfs_bio_clone(struct block_device *bdev, struct bio *bio);
 struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size);
 
 void end_extent_writepage(struct page *page, int err, u64 start, u64 end);

fs/btrfs/volumes.c

@@ -6824,12 +6824,13 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 			continue;
 		}
 
-		if (dev_nr < total_devs - 1)
-			bio = btrfs_bio_clone(first_bio);
-		else
+		if (dev_nr < total_devs - 1) {
+			bio = btrfs_bio_clone(dev->bdev, first_bio);
+		} else {
 			bio = first_bio;
+			bio_set_dev(bio, dev->bdev);
+		}
 
-		bio_set_dev(bio, dev->bdev);
 		submit_stripe_bio(bioc, bio, bioc->stripes[dev_nr].physical, dev);
 	}
 	btrfs_bio_counter_dec(fs_info);