gfs2: untangle the logic in gfs2_drevalidate

Before this patch, function gfs2_drevalidate was a horrific tangle of
unreadable labels, cases and goto statements. This patch tries to
simplify the logic and make it more readable.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/dentry.c

@@ -38,7 +38,7 @@ static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
 	struct inode *inode;
 	struct gfs2_holder d_gh;
 	struct gfs2_inode *ip = NULL;
-	int error;
+	int error, valid = 0;
 	int had_lock = 0;
 
 	if (flags & LOOKUP_RCU)
@@ -51,53 +51,30 @@ static int gfs2_drevalidate(struct dentry *dentry, unsigned int flags)
 
 	if (inode) {
 		if (is_bad_inode(inode))
-			goto invalid;
+			goto out;
 		ip = GFS2_I(inode);
 	}
 
-	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
-		goto valid;
+	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL) {
+		valid = 1;
+		goto out;
+	}
 
 	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
 	if (!had_lock) {
 		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
 		if (error)
-			goto fail;
-	} 
-
-	error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
-	switch (error) {
-	case 0:
-		if (!inode)
-			goto invalid_gunlock;
-		break;
-	case -ENOENT:
-		if (!inode)
-			goto valid_gunlock;
-		goto invalid_gunlock;
-	default:
-		goto fail_gunlock;
+			goto out;
 	}
 
-valid_gunlock:
-	if (!had_lock)
-		gfs2_glock_dq_uninit(&d_gh);
-valid:
-	dput(parent);
-	return 1;
+	error = gfs2_dir_check(d_inode(parent), &dentry->d_name, ip);
+	valid = inode ? !error : (error == -ENOENT);
 
-invalid_gunlock:
 	if (!had_lock)
 		gfs2_glock_dq_uninit(&d_gh);
-invalid:
+out:
 	dput(parent);
-	return 0;
-
-fail_gunlock:
-	gfs2_glock_dq_uninit(&d_gh);
-fail:
-	dput(parent);
-	return 0;
+	return valid;
 }
 
 static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)