gfs2: Get rid of gfs2_ilookup

Now that gfs2_lookup_by_inum only takes the inode glock for new inodes
(and not for cached inodes anymore), there no longer is a need to
optimize the cached-inode case in gfs2_get_dentry or delete_work_func,
and gfs2_ilookup can be removed.

In addition, gfs2_get_dentry wasn't checking the GFS2_DIF_SYSTEM flag in
i_diskflags in the gfs2_ilookup case (see gfs2_lookup_by_inum); this
inconsistency goes away as well.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index ce46375..1138a61 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -575,8 +575,7 @@
 {
 	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
-	struct gfs2_inode *ip;
-	struct inode *inode = NULL;
+	struct inode *inode;
 	u64 no_addr = gl->gl_name.ln_number;
 
 	/* If someone's using this glock to create a new dinode, the block must
@@ -585,13 +584,7 @@
 	if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
 		goto out;
 
-	ip = gl->gl_object;
-	/* Note: Unsafe to dereference ip as we don't hold right refs/locks */
-
-	if (ip)
-		inode = gfs2_ilookup(sdp->sd_vfs, no_addr);
-	if (IS_ERR_OR_NULL(inode))
-		inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
+	inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
 	if (inode && !IS_ERR(inode)) {
 		d_prune_aliases(inode);
 		iput(inode);