btrfs: store a block_device in struct btrfs_ordered_extent

Store the block device instead of the gendisk in the btrfs_ordered_extent
structure instead of acquiring a reference to it later.

Note: this is from series removing bdgrab/bdput, btrfs is one of the
last users.
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/inode.c

@@ -2992,7 +2992,7 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
 		goto out;
 	}
 
-	if (ordered_extent->disk)
+	if (ordered_extent->bdev)
 		btrfs_rewrite_logical_zoned(ordered_extent);
 
 	btrfs_free_io_failure_record(inode, start, end);

fs/btrfs/ordered-data.c

@@ -190,8 +190,6 @@ static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset
 	entry->truncated_len = (u64)-1;
 	entry->qgroup_rsv = ret;
 	entry->physical = (u64)-1;
-	entry->disk = NULL;
-	entry->partno = (u8)-1;
 
 	ASSERT(type == BTRFS_ORDERED_REGULAR ||
 	       type == BTRFS_ORDERED_NOCOW ||

fs/btrfs/ordered-data.h

@@ -145,8 +145,7 @@ struct btrfs_ordered_extent {
 	 * command in a workqueue context
 	 */
 	u64 physical;
-	struct gendisk *disk;
-	u8 partno;
+	struct block_device *bdev;
 };
 
 /*

fs/btrfs/zoned.c

@@ -1349,8 +1349,7 @@ void btrfs_record_physical_zoned(struct inode *inode, u64 file_offset,
 		return;
 
 	ordered->physical = physical;
-	ordered->disk = bio->bi_bdev->bd_disk;
-	ordered->partno = bio->bi_bdev->bd_partno;
+	ordered->bdev = bio->bi_bdev;
 
 	btrfs_put_ordered_extent(ordered);
 }
@@ -1362,18 +1361,16 @@ void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered)
 	struct extent_map_tree *em_tree;
 	struct extent_map *em;
 	struct btrfs_ordered_sum *sum;
-	struct block_device *bdev;
 	u64 orig_logical = ordered->disk_bytenr;
 	u64 *logical = NULL;
 	int nr, stripe_len;
 
 	/* Zoned devices should not have partitions. So, we can assume it is 0 */
-	ASSERT(ordered->partno == 0);
-	bdev = bdgrab(ordered->disk->part0);
-	if (WARN_ON(!bdev))
+	ASSERT(!bdev_is_partition(ordered->bdev));
+	if (WARN_ON(!ordered->bdev))
 		return;
 
-	if (WARN_ON(btrfs_rmap_block(fs_info, orig_logical, bdev,
+	if (WARN_ON(btrfs_rmap_block(fs_info, orig_logical, ordered->bdev,
 				     ordered->physical, &logical, &nr,
 				     &stripe_len)))
 		goto out;
@@ -1402,7 +1399,6 @@ void btrfs_rewrite_logical_zoned(struct btrfs_ordered_extent *ordered)
 
 out:
 	kfree(logical);
-	bdput(bdev);
 }
 
 bool btrfs_check_meta_write_pointer(struct btrfs_fs_info *fs_info,