GFS2: Merge lock_dlm module into GFS2

This is the big patch that I've been working on for some time
now. There are many reasons for wanting to make this change
such as:
 o Reducing overhead by eliminating duplicated fields between structures
 o Simplifcation of the code (reduces the code size by a fair bit)
 o The locking interface is now the DLM interface itself as proposed
   some time ago.
 o Fewer lookups of glocks when processing replies from the DLM
 o Fewer memory allocations/deallocations for each glock
 o Scope to do further optimisations in the future (but this patch is
   more than big enough for now!)

Please note that (a) this patch relates to the lock_dlm module and
not the DLM itself, that is still a separate module; and (b) that
we retain the ability to build GFS2 as a standalone single node
filesystem with out requiring the DLM.

This patch needs a lot of testing, hence my keeping it I restarted
my -git tree after the last merge window. That way, this has the maximum
exposure before its merged. This is (modulo a few minor bug fixes) the
same patch that I've been posting on and off the the last three months
and its passed a number of different tests so far.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/util.c

@@ -13,7 +13,6 @@
 #include <linux/buffer_head.h>
 #include <linux/crc32.h>
 #include <linux/gfs2_ondisk.h>
-#include <linux/lm_interface.h>
 #include <asm/uaccess.h>
 
 #include "gfs2.h"
@@ -35,6 +34,8 @@ void gfs2_assert_i(struct gfs2_sbd *sdp)
 
 int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
 {
+	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+	const struct lm_lockops *lm = ls->ls_ops;
 	va_list args;
 
 	if (test_and_set_bit(SDF_SHUTDOWN, &sdp->sd_flags))
@@ -47,8 +48,12 @@ int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
 	fs_err(sdp, "about to withdraw this file system\n");
 	BUG_ON(sdp->sd_args.ar_debug);
 
-	fs_err(sdp, "telling LM to withdraw\n");
-	gfs2_withdraw_lockproto(&sdp->sd_lockstruct);
+	kobject_uevent(&sdp->sd_kobj, KOBJ_OFFLINE);
+
+	if (lm->lm_unmount) {
+		fs_err(sdp, "telling LM to unmount\n");
+		lm->lm_unmount(sdp);
+	}
 	fs_err(sdp, "withdrawn\n");
 	dump_stack();