GFS2: Reinstate withdraw ack system

This patch reinstates the ack system which withdraw should be using. It
appears to have been accidentally forgotten when the lock module was
merged into GFS2, due to two different sysfs files having the same name.

Reported-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

4 files changed, 28 insertions, 1 deletions

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 1533cf8b4269..e2601ba38ef5 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -642,6 +642,7 @@ struct gfs2_sbd {
 	wait_queue_head_t sd_glock_wait;
 	atomic_t sd_glock_disposal;
 	struct completion sd_locking_init;
+	struct completion sd_wdack;
 	struct delayed_work sd_control_work;
 
 	/* Inode Stuff */
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index e063f22d9e4c..1b612be4b873 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -81,6 +81,7 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
 	init_waitqueue_head(&sdp->sd_glock_wait);
 	atomic_set(&sdp->sd_glock_disposal, 0);
 	init_completion(&sdp->sd_locking_init);
+	init_completion(&sdp->sd_wdack);
 	spin_lock_init(&sdp->sd_statfs_spin);
 
 	spin_lock_init(&sdp->sd_rindex_spin);
diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index 462e84142759..4fb9ad80d260 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -330,6 +330,28 @@ static ssize_t block_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
 	return ret;
 }
 
+static ssize_t wdack_show(struct gfs2_sbd *sdp, char *buf)
+{
+	int val = completion_done(&sdp->sd_wdack) ? 1 : 0;
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t wdack_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int val;
+
+	val = simple_strtol(buf, NULL, 0);
+
+	if ((val == 1) &&
+	    !strcmp(sdp->sd_lockstruct.ls_ops->lm_proto_name, "lock_dlm"))
+		complete(&sdp->sd_wdack);
+	else
+		ret = -EINVAL;
+	return ret;
+}
+
 static ssize_t lkfirst_show(struct gfs2_sbd *sdp, char *buf)
 {
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
@@ -461,7 +483,7 @@ static struct gfs2_attr gdlm_attr_##_name = __ATTR(_name,_mode,_show,_store)
 
 GDLM_ATTR(proto_name,		0444, proto_name_show,		NULL);
 GDLM_ATTR(block,		0644, block_show,		block_store);
-GDLM_ATTR(withdraw,		0644, withdraw_show,		withdraw_store);
+GDLM_ATTR(withdraw,		0644, wdack_show,		wdack_store);
 GDLM_ATTR(jid,			0644, jid_show,			jid_store);
 GDLM_ATTR(first,		0644, lkfirst_show,		lkfirst_store);
 GDLM_ATTR(first_done,		0444, first_done_show,		NULL);
diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index f00d7c5744f6..6402fb69d71b 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -54,6 +54,9 @@ int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
 
 		kobject_uevent(&sdp->sd_kobj, KOBJ_OFFLINE);
 
+		if (!strcmp(sdp->sd_lockstruct.ls_ops->lm_proto_name, "lock_dlm"))
+			wait_for_completion(&sdp->sd_wdack);
+
 		if (lm->lm_unmount) {
 			fs_err(sdp, "telling LM to unmount\n");
 			lm->lm_unmount(sdp);