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 <[e-mail]>
Cc: Ronnie Sahlberg <[e-mail]>
Cc: Ralph Böhme <[e-mail]>
Cc: Hyunchul Lee <[e-mail]>
Reported-by: Marios Makassikis <[e-mail]>
Tested-by: Marios Makassikis <[e-mail]>
Acked-by: Hyunchul Lee <[e-mail]>
Signed-off-by: Namjae Jeon <[e-mail]>
Signed-off-by: Steve French <[e-mail]>

fs/ksmbd/smb2pdu.c

···
 			       struct ksmbd_share_config *share)
 {
 	struct iattr attrs;
-	struct timespec64 ctime;
 	struct file *filp;
 	struct inode *inode;
 	struct user_namespace *user_ns;
···
 		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);
···
 			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;