btrfs: get rid of btrfs_add_nondir()

This is a trivial wrapper around btrfs_add_link(). The only thing it
does other than moving arguments around is translating a > 0 return
value to -EEXIST. As far as I can tell, btrfs_add_link() won't return >
0 (and if it did, the existing callsites in, e.g., btrfs_mkdir() would
be broken). The check itself dates back to commit 2c90e5d6 ("Btrfs:
still corruption hunting"), so it's probably left over from debugging.
Let's just get rid of btrfs_add_nondir().
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -6350,18 +6350,6 @@ int btrfs_add_link(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
-			    struct btrfs_inode *dir, struct dentry *dentry,
-			    struct btrfs_inode *inode, int backref, u64 index)
-{
-	int err = btrfs_add_link(trans, dir, inode,
-				 dentry->d_name.name, dentry->d_name.len,
-				 backref, index);
-	if (err > 0)
-		err = -EEXIST;
-	return err;
-}
-
 static int btrfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, dev_t rdev)
 {
@@ -6408,8 +6396,8 @@ static int btrfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	if (err)
 		goto out_unlock;
 
-	err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
-			0, index);
+	err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
+			     dentry->d_name.name, dentry->d_name.len, 0, index);
 	if (err)
 		goto out_unlock;
 
@@ -6476,8 +6464,8 @@ static int btrfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 	if (err)
 		goto out_unlock;
 
-	err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
-			0, index);
+	err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
+			     dentry->d_name.name, dentry->d_name.len, 0, index);
 	if (err)
 		goto out_unlock;
 
@@ -6536,8 +6524,8 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	ihold(inode);
 	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
 
-	err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
-			1, index);
+	err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
+			     dentry->d_name.name, dentry->d_name.len, 1, index);
 
 	if (err) {
 		drop_inode = 1;
@@ -9317,8 +9305,8 @@ static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
 	if (ret)
 		goto out;
 
-	ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
-				BTRFS_I(inode), 0, index);
+	ret = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
+			     dentry->d_name.name, dentry->d_name.len, 0, index);
 	if (ret)
 		goto out;
 
@@ -9856,8 +9844,9 @@ static int btrfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 	 * elsewhere above.
 	 */
 	if (!err)
-		err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
-				BTRFS_I(inode), 0, index);
+		err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
+				     dentry->d_name.name, dentry->d_name.len, 0,
+				     index);
 	if (err)
 		goto out_unlock;