selinux: fix error initialization in inode_doinit_with_dentry()

Mark the inode security label as invalid if we cannot find
a dentry so that we will retry later rather than marking it
initialized with the unlabeled SID.

Fixes: 9287aed ("selinux: Convert isec->lock into a spinlock")
Signed-off-by: Tianyue Ren <rentianyue@kylinos.cn>
[PM: minor comment tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/hooks.c

@@ -1451,7 +1451,13 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			 * inode_doinit with a dentry, before these inodes could
 			 * be used again by userspace.
 			 */
-			goto out;
+			isec->initialized = LABEL_INVALID;
+			/*
+			 * There is nothing useful to jump to the "out"
+			 * label, except a needless spin lock/unlock
+			 * cycle.
+			 */
+			return 0;
 		}
 
 		rc = inode_doinit_use_xattr(inode, dentry, sbsec->def_sid,
@@ -1507,8 +1513,15 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			 * inode_doinit() with a dentry, before these inodes
 			 * could be used again by userspace.
 			 */
-			if (!dentry)
-				goto out;
+			if (!dentry) {
+				isec->initialized = LABEL_INVALID;
+				/*
+				 * There is nothing useful to jump to the "out"
+				 * label, except a needless spin lock/unlock
+				 * cycle.
+				 */
+				return 0;
+			}
 			rc = selinux_genfs_get_sid(dentry, sclass,
 						   sbsec->flags, &sid);
 			if (rc) {