ksmbd: Fix resource leak in smb2_lock()

"flock" is leaked if an error happens before smb2_lock_init(), as the
lock is not added to the lock_list to be cleaned up.
Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -6857,6 +6857,7 @@ int smb2_lock(struct ksmbd_work *work)
 		if (lock_start > U64_MAX - lock_length) {
 			pr_err("Invalid lock range requested\n");
 			rsp->hdr.Status = STATUS_INVALID_LOCK_RANGE;
+			locks_free_lock(flock);
 			goto out;
 		}
 
@@ -6876,6 +6877,7 @@ int smb2_lock(struct ksmbd_work *work)
 				    "the end offset(%llx) is smaller than the start offset(%llx)\n",
 				    flock->fl_end, flock->fl_start);
 			rsp->hdr.Status = STATUS_INVALID_LOCK_RANGE;
+			locks_free_lock(flock);
 			goto out;
 		}
 
@@ -6887,6 +6889,7 @@ int smb2_lock(struct ksmbd_work *work)
 				    flock->fl_type != F_UNLCK) {
 					pr_err("conflict two locks in one request\n");
 					err = -EINVAL;
+					locks_free_lock(flock);
 					goto out;
 				}
 			}
@@ -6895,6 +6898,7 @@ int smb2_lock(struct ksmbd_work *work)
 		smb_lock = smb2_lock_init(flock, cmd, flags, &lock_list);
 		if (!smb_lock) {
 			err = -EINVAL;
+			locks_free_lock(flock);
 			goto out;
 		}
 	}