gfs2: Fix inode height consistency check

The maximum allowed height of an inode's metadata tree depends on the
filesystem block size; it is lower for bigger-block filesystems.  When
reading in an inode, make sure that the height doesn't exceed the
maximum allowed height.

Arrays like sd_heightsize are sized to be big enough for any filesystem
block size; they will often be slightly bigger than what's needed for a
specific filesystem.

Reported-by: syzbot+45d4691b1ed3c48eba05@syzkaller.appspotmail.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Author: Andreas Gruenbacher

fs/gfs2/glops.c

@@ -396,6 +396,7 @@ static int inode_go_demote_ok(const struct gfs2_glock *gl)
 
 static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 {
+	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 	const struct gfs2_dinode *str = buf;
 	struct timespec64 atime;
 	u16 height, depth;
@@ -442,7 +443,7 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 	/* i_diskflags and i_eattr must be set before gfs2_set_inode_flags() */
 	gfs2_set_inode_flags(inode);
 	height = be16_to_cpu(str->di_height);
-	if (unlikely(height > GFS2_MAX_META_HEIGHT))
+	if (unlikely(height > sdp->sd_max_height))
 		goto corrupt;
 	ip->i_height = (u8)height;