btrfs: zoned: pass start block to btrfs_use_zone_append

btrfs_use_zone_append only needs the passed in extent_map's block_start
member, so there's no need to pass in the full extent map.

This also enables the use of btrfs_use_zone_append in places where we only
have a start byte but no extent_map.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 304ce64..1bb8ee9 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -1278,7 +1278,7 @@ void btrfs_free_redirty_list(struct btrfs_transaction *trans)
 	spin_unlock(&trans->releasing_ebs_lock);
 }
 
-bool btrfs_use_zone_append(struct btrfs_inode *inode, struct extent_map *em)
+bool btrfs_use_zone_append(struct btrfs_inode *inode, u64 start)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	struct btrfs_block_group *cache;
@@ -1293,7 +1293,7 @@ bool btrfs_use_zone_append(struct btrfs_inode *inode, struct extent_map *em)
 	if (!is_data_inode(&inode->vfs_inode))
 		return false;
 
-	cache = btrfs_lookup_block_group(fs_info, em->block_start);
+	cache = btrfs_lookup_block_group(fs_info, start);
 	ASSERT(cache);
 	if (!cache)
 		return false;