[Cluster-devel] GFS2: Remove loopy umount code

[Steven Whitehouse <swhiteho@redhat.com>]

This is a follow up to the patch I posted yesterday and does
the "next bit" of the changes.

From 69a14ddaf57449c3f6ecfe96a898df5ded1a4256 Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho@redhat.com>
Date: Tue, 8 Dec 2009 15:45:50 +0000
Subject: GFS2: Remove loopy umount code

As a consequence of the previous patch, we can now remove the
loop which used to be required due to the circular dependency
between the inodes and glocks. Instead we can just invalidate
the inodes, and then clear up any glocks which are left.

Also we no longer need the rwsem since there is no longer any
danger of the inode invalidation calling back into the glock
code (and from there back into the inode code).

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---
 fs/gfs2/glock.c      |   35 ++++-------------------------------
 fs/gfs2/ops_fstype.c |    3 +--
 fs/gfs2/super.c      |    1 +
 3 files changed, 6 insertions(+), 33 deletions(-)

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 736d05b..6e1e526 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -19,7 +19,6 @@
 #include <linux/list.h>
 #include <linux/wait.h>
 #include <linux/module.h>
-#include <linux/rwsem.h>
 #include <asm/uaccess.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
@@ -60,7 +59,6 @@ static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0)
 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
 
-static DECLARE_RWSEM(gfs2_umount_flush_sem);
 static struct dentry *gfs2_root;
 static struct workqueue_struct *glock_workqueue;
 struct workqueue_struct *gfs2_delete_workqueue;
@@ -714,7 +712,6 @@ static void glock_work_func(struct work_struct *work)
 		finish_xmote(gl, gl->gl_reply);
 		drop_ref = 1;
 	}
-	down_read(&gfs2_umount_flush_sem);
 	spin_lock(&gl->gl_spin);
 	if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
 	    gl->gl_state != LM_ST_UNLOCKED &&
@@ -727,7 +724,6 @@ static void glock_work_func(struct work_struct *work)
 	}
 	run_queue(gl, 0);
 	spin_unlock(&gl->gl_spin);
-	up_read(&gfs2_umount_flush_sem);
 	if (!delay ||
 	    queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
 		gfs2_glock_put(gl);
@@ -1511,35 +1507,12 @@ void gfs2_glock_thaw(struct gfs2_sbd *sdp)
 
 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
 {
-	unsigned long t;
 	unsigned int x;
-	int cont;
 
-	t = jiffies;
-
-	for (;;) {
-		cont = 0;
-		for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
-			if (examine_bucket(clear_glock, sdp, x))
-				cont = 1;
-		}
-
-		if (!cont)
-			break;
-
-		if (time_after_eq(jiffies,
-				  t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
-			fs_warn(sdp, "Unmount seems to be stalled. "
-				     "Dumping lock state...\n");
-			gfs2_dump_lockstate(sdp);
-			t = jiffies;
-		}
-
-		down_write(&gfs2_umount_flush_sem);
-		invalidate_inodes(sdp->sd_vfs);
-		up_write(&gfs2_umount_flush_sem);
-		msleep(10);
-	}
+	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
+		examine_bucket(clear_glock, sdp, x);
+	flush_workqueue(glock_workqueue);
+	gfs2_dump_lockstate(sdp);
 }
 
 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index edfee24..717222a 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1231,10 +1231,9 @@ fail_sb:
 fail_locking:
 	init_locking(sdp, &mount_gh, UNDO);
 fail_lm:
+	invalidate_inodes(sb);
 	gfs2_gl_hash_clear(sdp);
 	gfs2_lm_unmount(sdp);
-	while (invalidate_inodes(sb))
-		yield();
 fail_sys:
 	gfs2_sys_fs_del(sdp);
 fail:
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 8ddc613..c008b08 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -858,6 +858,7 @@ restart:
 	gfs2_clear_rgrpd(sdp);
 	gfs2_jindex_free(sdp);
 	/*  Take apart glock structures and buffer lists  */
+	invalidate_inodes(sdp->sd_vfs);
 	gfs2_gl_hash_clear(sdp);
 	/*  Unmount the locking protocol  */
 	gfs2_lm_unmount(sdp);
-- 
1.6.2.5