Revert "GFS2: Don't add all glocks to the lru"

This reverts commit e7ccaf5.

Before commit e7ccaf5, every time a resource group glock was
dequeued by gfs2_glock_dq(), it was added to the glock LRU list even
though the glock was still referenced by the resource group and could
never be evicted, anyway.  Commit e7ccaf5 added a GLOF_LRU hack to
avoid that overhead for resource group glocks, and that hack was since
adopted for some other types of glocks as well.

We now no longer add glocks to the glock LRU list while they are still
referenced.  This solves the underlying problem, and obsoletes the
GLOF_LRU hack.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
(cherry picked from commit 3e5257c810cba91e274d07f3db5cf013c7c830be)

Author: Andreas Gruenbacher

fs/gfs2/glock.c

@@ -239,11 +239,7 @@ static int demote_ok(const struct gfs2_glock *gl)
 
 static void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
 {
-	if (!(gl->gl_ops->go_flags & GLOF_LRU))
-		return;
-
 	spin_lock(&lru_lock);
-
 	list_move_tail(&gl->gl_lru, &lru_list);
 
 	if (!test_bit(GLF_LRU, &gl->gl_flags)) {
@@ -256,9 +252,6 @@ static void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
 
 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
 {
-	if (!(gl->gl_ops->go_flags & GLOF_LRU))
-		return;
-
 	spin_lock(&lru_lock);
 	if (test_bit(GLF_LRU, &gl->gl_flags)) {
 		list_del_init(&gl->gl_lru);

fs/gfs2/glops.c

@@ -727,7 +727,7 @@ const struct gfs2_glock_operations gfs2_inode_glops = {
 	.go_held = inode_go_held,
 	.go_dump = inode_go_dump,
 	.go_type = LM_TYPE_INODE,
-	.go_flags = GLOF_ASPACE | GLOF_LRU | GLOF_LVB,
+	.go_flags = GLOF_ASPACE | GLOF_LVB,
 	.go_unlocked = inode_go_unlocked,
 };
 
@@ -751,13 +751,13 @@ const struct gfs2_glock_operations gfs2_iopen_glops = {
 	.go_type = LM_TYPE_IOPEN,
 	.go_callback = iopen_go_callback,
 	.go_dump = inode_go_dump,
-	.go_flags = GLOF_LRU | GLOF_NONDISK,
+	.go_flags = GLOF_NONDISK,
 	.go_subclass = 1,
 };
 
 const struct gfs2_glock_operations gfs2_flock_glops = {
 	.go_type = LM_TYPE_FLOCK,
-	.go_flags = GLOF_LRU | GLOF_NONDISK,
+	.go_flags = GLOF_NONDISK,
 };
 
 const struct gfs2_glock_operations gfs2_nondisk_glops = {
@@ -768,7 +768,7 @@ const struct gfs2_glock_operations gfs2_nondisk_glops = {
 
 const struct gfs2_glock_operations gfs2_quota_glops = {
 	.go_type = LM_TYPE_QUOTA,
-	.go_flags = GLOF_LVB | GLOF_LRU | GLOF_NONDISK,
+	.go_flags = GLOF_LVB | GLOF_NONDISK,
 };
 
 const struct gfs2_glock_operations gfs2_journal_glops = {

fs/gfs2/incore.h

@@ -230,7 +230,6 @@ struct gfs2_glock_operations {
 	const unsigned long go_flags;
 #define GLOF_ASPACE 1 /* address space attached */
 #define GLOF_LVB    2 /* Lock Value Block attached */
-#define GLOF_LRU    4 /* LRU managed */
 #define GLOF_NONDISK   8 /* not I/O related */
 };