ext2fs(4): Fix a null dererence and clean an unclear switch

Coverity warned that the switch statement fell through.  While this was
intentional, the pattern wasn't especially clear.  I just changed it to a
conventional if pattern.

Reported by:	Coverity
CIDs:		1375851 (false positive), 1375853
Sponsored by:	Dell EMC Isilon

1 files changed, 20 insertions, 17 deletions

diff --git a/sys/fs/ext2fs/ext2_acl.c b/sys/fs/ext2fs/ext2_acl.c
index afea23da933d..0f47c2981f94 100644
--- a/sys/fs/ext2fs/ext2_acl.c
+++ b/sys/fs/ext2fs/ext2_acl.c
@@ -127,13 +127,18 @@ ext2_sync_inode_from_acl(struct acl *acl, struct inode *ip)
 static int
 ext4_acl_from_disk(char *value, size_t size, struct acl *acl)
 {
-	const char *end = value + size;
+	const char *end;
 	int n, count, s;
 
+	if (value == NULL)
+		return (EINVAL);
+
+	end = value + size;
+
 	if (((struct ext2_acl_header *)value)->a_version != EXT4_ACL_VERSION)
 		return (EINVAL);
 
-	if (!value || size < sizeof(struct ext2_acl_header))
+	if (size < sizeof(struct ext2_acl_header))
 		return (EINVAL);
 
 	s = size - sizeof(struct ext2_acl_header);
@@ -230,8 +235,7 @@ ext2_getacl_posix1e(struct vop_getacl_args *ap)
 
 	error = vn_extattr_get(ap->a_vp, IO_NODELOCKED, attrnamespace, attrname,
 	    &len, value, ap->a_td);
-	switch (error) {
-	case ENOATTR:
+	if (error == ENOATTR) {
 		switch (ap->a_type) {
 		case ACL_TYPE_ACCESS:
 			ap->a_aclp->acl_cnt = 3;
@@ -250,22 +254,21 @@ ext2_getacl_posix1e(struct vop_getacl_args *ap)
 			ap->a_aclp->acl_cnt = 0;
 			break;
 		}
-	case 0:
-		if (!error) {
-			error = ext4_acl_from_disk(value, len, ap->a_aclp);
-			if (error)
-				goto out;
-		}
-
-		if (error == ENOATTR)
-			error = 0;
+	} else if (error != 0)
+		goto out;
 
-		if (ap->a_type == ACL_TYPE_ACCESS)
-			ext2_sync_acl_from_inode(VTOI(ap->a_vp), ap->a_aclp);
-	default:
-		break;
+	if (!error) {
+		error = ext4_acl_from_disk(value, len, ap->a_aclp);
+		if (error)
+			goto out;
 	}
 
+	if (error == ENOATTR)
+		error = 0;
+
+	if (ap->a_type == ACL_TYPE_ACCESS)
+		ext2_sync_acl_from_inode(VTOI(ap->a_vp), ap->a_aclp);
+
 out:
 	free(value, M_TEMP);
 	return (error);