[PATCH 1/2] btrfs: remove conditional path allocation from read_locked_inode, add path allocation to iget

[Leo Martins <loemra.dev@gmail.com>]

Move the path allocation from inside btrfs_read_locked_inode to
btrfs_iget. This makes the code easier to reason about as it is clear
where the allocation occurs and who is in charge of freeing the path.
I have investigated all of the callers of btrfs_iget_path to make sure 
that it is never called with a null path with the expectation
of a path allocation. All of the null calls seem to come from btrfs_iget
so it makes sense to do the allocation within btrfs_iget.

---
 fs/btrfs/inode.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 07858d63378f..b89b4b1bd3da 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3790,10 +3790,9 @@ static int btrfs_init_file_extent_tree(struct btrfs_inode *inode)
  * read an inode from the btree into the in-memory inode
  */
 static int btrfs_read_locked_inode(struct inode *inode,
-				   struct btrfs_path *in_path)
+				   struct btrfs_path *path)
 {
 	struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
-	struct btrfs_path *path = in_path;
 	struct extent_buffer *leaf;
 	struct btrfs_inode_item *inode_item;
 	struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -3813,18 +3812,10 @@ static int btrfs_read_locked_inode(struct inode *inode,
 	if (!ret)
 		filled = true;
 
-	if (!path) {
-		path = btrfs_alloc_path();
-		if (!path)
-			return -ENOMEM;
-	}
-
 	btrfs_get_inode_key(BTRFS_I(inode), &location);
 
 	ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
 	if (ret) {
-		if (path != in_path)
-			btrfs_free_path(path);
 		return ret;
 	}
 
@@ -3960,8 +3951,6 @@ static int btrfs_read_locked_inode(struct inode *inode,
 				  btrfs_ino(BTRFS_I(inode)),
 				  btrfs_root_id(root), ret);
 	}
-	if (path != in_path)
-		btrfs_free_path(path);
 
 	if (!maybe_acls)
 		cache_no_acl(inode);
@@ -5631,7 +5620,15 @@ struct inode *btrfs_iget_path(u64 ino, struct btrfs_root *root,
 
 struct inode *btrfs_iget(u64 ino, struct btrfs_root *root)
 {
-	return btrfs_iget_path(ino, root, NULL);
+	struct btrfs_path *path = btrfs_alloc_path();
+
+	if (!path)
+		return ERR_PTR(-ENOMEM);
+
+	struct inode *inode = btrfs_iget_path(ino, root, path);
+
+	btrfs_free_path(path);
+	return inode;
 }
 
 static struct inode *new_simple_dir(struct inode *dir,
-- 
2.43.5