ext4: fix EXT4_IOC_GROUP_ADD ioctl

BugLink: https://bugs.launchpad.net/bugs/1811647

commit e647e291 upstream.

Commit e2b911c5 ("ext4: clean up feature test macros with
predicate functions") broke the EXT4_IOC_GROUP_ADD ioctl.  This was
not noticed since only very old versions of resize2fs (before
e2fsprogs 1.42) use this ioctl.  However, using a new kernel with an
enterprise Linux userspace will cause attempts to use online resize to
fail with "No reserved GDT blocks".

Fixes: e2b911c5 ("ext4: clean up feature test macros with predicate...")
Cc: stable@kernel.org # v4.4
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: ruippan (潘睿) <ruippan@tencent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

fs/ext4/resize.c

@@ -1600,7 +1600,7 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 	}
 
 	if (reserved_gdb || gdb_off == 0) {
-		if (ext4_has_feature_resize_inode(sb) ||
+		if (!ext4_has_feature_resize_inode(sb) ||
 		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
 			ext4_warning(sb,
 				     "No reserved GDT blocks, can't resize");