smb: client: Fix refcount leak for cifs_sb_tlink

Fix three refcount inconsistency issues related to `cifs_sb_tlink`.

Comments for `cifs_sb_tlink` state that `cifs_put_tlink()` needs to be
called after successful calls to `cifs_sb_tlink()`. Three calls fail to
update refcount accordingly, leading to possible resource leaks.

Fixes: 8ceb984 ("CIFS: Move rename to ops struct")
Fixes: 2f1afe2 ("cifs: Use smb 2 - 3 and cifsacl mount options getacl functions")
Fixes: 366ed84 ("cifs: Use smb 2 - 3 and cifsacl mount options setacl function")
Cc: [email protected]
Signed-off-by: Shuhao Fu <[email protected]>
Signed-off-by: Steve French <[email protected]>

Author: sfu2

fs/smb/client/inode.c

@@ -2431,8 +2431,10 @@ cifs_do_rename(const unsigned int xid, struct dentry *from_dentry,
 	tcon = tlink_tcon(tlink);
 	server = tcon->ses->server;
 
-	if (!server->ops->rename)
-		return -ENOSYS;
+	if (!server->ops->rename) {
+		rc = -ENOSYS;
+		goto do_rename_exit;
+	}
 
 	/* try path-based rename first */
 	rc = server->ops->rename(xid, tcon, from_dentry,

fs/smb/client/smb2ops.c

@@ -3212,8 +3212,7 @@ get_smb2_acl_by_path(struct cifs_sb_info *cifs_sb,
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path) {
 		rc = -ENOMEM;
-		free_xid(xid);
-		return ERR_PTR(rc);
+		goto put_tlink;
 	}
 
 	oparms = (struct cifs_open_parms) {
@@ -3245,6 +3244,7 @@ get_smb2_acl_by_path(struct cifs_sb_info *cifs_sb,
 		SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 	}
 
+put_tlink:
 	cifs_put_tlink(tlink);
 	free_xid(xid);
 
@@ -3285,8 +3285,7 @@ set_smb2_acl(struct smb_ntsd *pnntsd, __u32 acllen,
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path) {
 		rc = -ENOMEM;
-		free_xid(xid);
-		return rc;
+		goto put_tlink;
 	}
 
 	oparms = (struct cifs_open_parms) {
@@ -3307,6 +3306,7 @@ set_smb2_acl(struct smb_ntsd *pnntsd, __u32 acllen,
 		SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
 	}
 
+put_tlink:
 	cifs_put_tlink(tlink);
 	free_xid(xid);
 	return rc;