btrfs: directly pass the inode to btrfs_is_data_extent_shared()

Currently we pass a root and an inode number as arguments for
btrfs_is_data_extent_shared() and the inode number is always from an
inode that belongs to that root (it wouldn't make sense otherwise).
In every context that we call btrfs_is_data_extent_shared() (fiemap only),
we have an inode available, so directly pass the inode to the function
instead of a root and inode number. This reduces the number of parameters
and it makes the function's signature conform to most other functions we
have.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/backref.c

@@ -1658,8 +1658,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
 /*
  * Check if a data extent is shared or not.
  *
- * @root:        The root the inode belongs to.
- * @inum:        Number of the inode whose extent we are checking.
+ * @inode:       The inode whose extent we are checking.
  * @bytenr:      Logical bytenr of the extent we are checking.
  * @extent_gen:  Generation of the extent (file extent item) or 0 if it is
  *               not known.
@@ -1678,11 +1677,12 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache,
  *
  * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.
  */
-int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
+int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 				u64 extent_gen,
 				struct ulist *roots, struct ulist *tmp,
 				struct btrfs_backref_shared_cache *cache)
 {
+	struct btrfs_root *root = inode->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct btrfs_trans_handle *trans;
 	struct ulist_iterator uiter;
@@ -1691,7 +1691,7 @@ int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
 	int ret = 0;
 	struct share_check shared = {
 		.root_objectid = root->root_key.objectid,
-		.inum = inum,
+		.inum = btrfs_ino(inode),
 		.share_count = 0,
 		.have_delayed_delete_refs = false,
 	};

fs/btrfs/backref.h

@@ -77,7 +77,7 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
 			  u64 start_off, struct btrfs_path *path,
 			  struct btrfs_inode_extref **ret_extref,
 			  u64 *found_off);
-int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
+int btrfs_is_data_extent_shared(struct btrfs_inode *inode, u64 bytenr,
 				u64 extent_gen,
 				struct ulist *roots, struct ulist *tmp,
 				struct btrfs_backref_shared_cache *cache);

fs/btrfs/extent_io.c

@@ -3712,7 +3712,6 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 			       u64 start, u64 end)
 {
 	const u64 i_size = i_size_read(&inode->vfs_inode);
-	const u64 ino = btrfs_ino(inode);
 	u64 cur_offset = start;
 	u64 last_delalloc_end = 0;
 	u32 prealloc_flags = FIEMAP_EXTENT_UNWRITTEN;
@@ -3752,8 +3751,8 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 
 		if (prealloc_len > 0) {
 			if (!checked_extent_shared && fieinfo->fi_extents_max) {
-				ret = btrfs_is_data_extent_shared(inode->root,
-							  ino, disk_bytenr,
+				ret = btrfs_is_data_extent_shared(inode,
+							  disk_bytenr,
 							  extent_gen, roots,
 							  tmp_ulist,
 							  backref_cache);
@@ -3802,8 +3801,8 @@ static int fiemap_process_hole(struct btrfs_inode *inode,
 		}
 
 		if (!checked_extent_shared && fieinfo->fi_extents_max) {
-			ret = btrfs_is_data_extent_shared(inode->root,
-							  ino, disk_bytenr,
+			ret = btrfs_is_data_extent_shared(inode,
+							  disk_bytenr,
 							  extent_gen, roots,
 							  tmp_ulist,
 							  backref_cache);
@@ -3904,7 +3903,6 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 	const u64 ino = btrfs_ino(inode);
 	struct extent_state *cached_state = NULL;
 	struct btrfs_path *path;
-	struct btrfs_root *root = inode->root;
 	struct fiemap_cache cache = { 0 };
 	struct btrfs_backref_shared_cache *backref_cache;
 	struct ulist *roots;
@@ -3925,8 +3923,8 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		goto out;
 	}
 
-	lockstart = round_down(start, root->fs_info->sectorsize);
-	lockend = round_up(start + len, root->fs_info->sectorsize);
+	lockstart = round_down(start, inode->root->fs_info->sectorsize);
+	lockend = round_up(start + len, inode->root->fs_info->sectorsize);
 	prev_extent_end = lockstart;
 
 	lock_extent(&inode->io_tree, lockstart, lockend, &cached_state);
@@ -4034,7 +4032,7 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
 		} else {
 			/* We have a regular extent. */
 			if (fieinfo->fi_extents_max) {
-				ret = btrfs_is_data_extent_shared(root, ino,
+				ret = btrfs_is_data_extent_shared(inode,
 								  disk_bytenr,
 								  extent_gen,
 								  roots,