gfs2: gfs2_create_inode error handling fix

JIRA: https://issues.redhat.com/browse/RHEL-88093
Upstream Status: https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git

When gfs2_create_inode() finds a directory, make sure to return -EISDIR.

Fixes: 571a4b5 ("GFS2: bugger off early if O_CREAT open finds a directory")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
(cherry picked from commit 3a45c0cc8004aa5b1f0dfad05fe44b0a136f024f)

Author: Andreas Gruenbacher

fs/gfs2/inode.c

@@ -651,7 +651,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (!IS_ERR(inode)) {
 		if (S_ISDIR(inode->i_mode)) {
 			iput(inode);
-			inode = ERR_PTR(-EISDIR);
+			inode = NULL;
+			error = -EISDIR;
 			goto fail_gunlock;
 		}
 		d_instantiate(dentry, inode);