ksmbd: fix oops from fuse driver

Marios reported kernel oops from fuse driver when ksmbd call
mark_inode_dirty(). This patch directly update ->i_ctime after removing
mark_inode_ditry() and notify_change will put inode to dirty list.

Cc: Tom Talpey <tom@talpey.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Böhme <slow@samba.org>
Cc: Hyunchul Lee <hyc.lee@gmail.com>
Reported-by: Marios Makassikis <mmakassikis@freebox.fr>
Tested-by: Marios Makassikis <mmakassikis@freebox.fr>
Acked-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -5483,7 +5483,6 @@ static int set_file_basic_info(struct ksmbd_file *fp,
 			       struct ksmbd_share_config *share)
 {
 	struct iattr attrs;
-	struct timespec64 ctime;
 	struct file *filp;
 	struct inode *inode;
 	struct user_namespace *user_ns;
@@ -5505,13 +5504,11 @@ static int set_file_basic_info(struct ksmbd_file *fp,
 		attrs.ia_valid |= (ATTR_ATIME | ATTR_ATIME_SET);
 	}
 
-	if (file_info->ChangeTime) {
+	attrs.ia_valid |= ATTR_CTIME;
+	if (file_info->ChangeTime)
 		attrs.ia_ctime = ksmbd_NTtimeToUnix(file_info->ChangeTime);
-		ctime = attrs.ia_ctime;
-		attrs.ia_valid |= ATTR_CTIME;
-	} else {
-		ctime = inode->i_ctime;
-	}
+	else
+		attrs.ia_ctime = inode->i_ctime;
 
 	if (file_info->LastWriteTime) {
 		attrs.ia_mtime = ksmbd_NTtimeToUnix(file_info->LastWriteTime);
@@ -5557,11 +5554,9 @@ static int set_file_basic_info(struct ksmbd_file *fp,
 			return -EACCES;
 
 		inode_lock(inode);
+		inode->i_ctime = attrs.ia_ctime;
+		attrs.ia_valid &= ~ATTR_CTIME;
 		rc = notify_change(user_ns, dentry, &attrs, NULL);
-		if (!rc) {
-			inode->i_ctime = ctime;
-			mark_inode_dirty(inode);
-		}
 		inode_unlock(inode);
 	}
 	return rc;