[Ocfs2-tools-devel] [PATCH 1/6] ocfs2_hb_ctl: Use ocfs2_hb_ctl again for o2cb umount(2).

[Joel Becker]

We've determined that mountpoints cannot be safely tracked from
userspace.  The only safe place to leave a filesystem group is in
put_super(7).  We used to do this via ocfs2_hb_ctl, and we're going to
do so again.

This change does three things:

1) Puts ocfs2_hb_ctl(8) back in /proc/sys/fs/ocfs2/nm/hb_ctl_path
2) Teaches ocfs2_hb_ctl(8) to do nothing when the cluster stack isn't o2cb
3) Teaches umount.ocfs2(8) to skip cluster interaction when the cluster
   stack *is* o2cb.

Thus, ocfs2_hb_ctl(8) is used for o2cb clusters and umount.ocfs2(8) is
used for all other cluster stacks.  Future changes will add support for
all cluster stacks to ocfs2_hb_ctk(8), removing the need for
umount.ocfs2(8).

Signed-off-by: Joel Becker <joel.becker at oracle.com>
---
 mount.ocfs2/umount.ocfs2.c  |   11 ++++++++++-
 ocfs2_hb_ctl/ocfs2_hb_ctl.c |   29 ++++++++++++++++++++++++++---
 vendor/common/o2cb.init.sh  |   12 ------------
 3 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/mount.ocfs2/umount.ocfs2.c b/mount.ocfs2/umount.ocfs2.c
index 81d1382..fe49753 100644
--- a/mount.ocfs2/umount.ocfs2.c
+++ b/mount.ocfs2/umount.ocfs2.c
@@ -146,6 +146,7 @@ int main(int argc, char **argv)
 	struct o2cb_cluster_desc cluster;
 	struct o2cb_region_desc desc;
 	int clustered = 1;
+	const char *stack = "";
 
 	initialize_ocfs_error_table();
 	initialize_o2dl_error_table();
@@ -189,6 +190,13 @@ int main(int argc, char **argv)
 			goto bail;
 		}
 
+		ret = o2cb_get_stack_name(&stack);
+		if (ret) {
+			com_err(progname, ret, "while querying cluster stack");
+			ret = -EINVAL;
+			goto bail;
+		}
+
 		ret = ocfs2_fill_cluster_desc(fs, &cluster);
 		if (ret) {
 			com_err(progname, ret,
@@ -232,7 +240,8 @@ int main(int argc, char **argv)
 	if (rc)
 		goto unblock;
 
-	if (clustered) {
+	/* For now, only call group_leave for non-o2cb stacks */
+	if (clustered && strcmp(stack, "o2cb")) {
 		ret = o2cb_group_leave(&cluster, &desc);
 		if (ret) {
 			com_err(progname, ret,
diff --git a/ocfs2_hb_ctl/ocfs2_hb_ctl.c b/ocfs2_hb_ctl/ocfs2_hb_ctl.c
index 88c60a8..5cf3485 100644
--- a/ocfs2_hb_ctl/ocfs2_hb_ctl.c
+++ b/ocfs2_hb_ctl/ocfs2_hb_ctl.c
@@ -45,6 +45,7 @@
 #define DEV_PREFIX      "/dev/"
 #define PROC_IDE_FORMAT "/proc/ide/%s/media"
 #define IONICE_PATH	"/usr/bin/ionice"
+#define MOUNT_SERVICE	"mount.ocfs2"
 
 enum hb_ctl_action {
 	HB_ACTION_UNKNOWN,
@@ -452,9 +453,17 @@ static int process_options(struct hb_ctl_options *hbo)
 	case HB_ACTION_STOP:
 		/* For stop must specify exactly one of uuid or device. */
 		if ((hbo->uuid_str && hbo->dev_str) ||
-		    (!hbo->uuid_str && !hbo->dev_str) ||
-		    !hbo->service)
-			ret = -EINVAL;
+		    (!hbo->uuid_str && !hbo->dev_str))
+		       ret = -EINVAL;
+		else if (!hbo->service) {
+			/* This is a special case - the kernel calls us
+			 * with uuid_str and ! service.  In that case only
+			 * we fill in the service */
+			if (hbo->uuid_str)
+				hbo->service = strdup(MOUNT_SERVICE);
+			else
+				ret = -EINVAL;
+		}
 		break;
 
 	case HB_ACTION_REFINFO:
@@ -507,6 +516,7 @@ int main(int argc, char **argv)
 		.action = HB_ACTION_UNKNOWN,
 	};
 	char hbuuid[33];
+	const char *stack = "";
 
 	setbuf(stdout, NULL);
 	setbuf(stderr, NULL);
@@ -539,6 +549,19 @@ int main(int argc, char **argv)
 		goto bail;
 	}
 
+	err = o2cb_get_stack_name(&stack);
+	if (err) {
+		com_err(progname, err, "while querying cluster stack");
+		ret = -EINVAL;
+		goto bail;
+	}
+
+	/* For now, skip non-o2cb stacks */
+	if (strcmp(stack, "o2cb")) {
+		ret = 0;
+		goto bail;
+	}
+
 	if (!hbo.uuid_str) {
 		err = get_uuid(hbo.dev_str, hbuuid);
 		if (err) {
diff --git a/vendor/common/o2cb.init.sh b/vendor/common/o2cb.init.sh
index 4269e6e..810b004 100644
--- a/vendor/common/o2cb.init.sh
+++ b/vendor/common/o2cb.init.sh
@@ -896,18 +896,6 @@ load_stack_o2cb()
     mount_filesystem "ocfs2_dlmfs" "/dlm"
     if_fail $?
 
-    #
-    # This version of ocfs2-tools relies on umount.ocfs2, so we don't need
-    # to call ocfs2_hb_ctl from the kernel.  Given that older drivers may
-    # still want to, we have them just call /bin/true.
-    #
-    echo "/bin/true" >/proc/sys/fs/ocfs2/nm/hb_ctl_path
-    if [ $? != 0 ]
-    then
-        echo -n "Clearing kernel heartbeat control path: "
-        if_fail 1 "Unable to set hb_ctl_path"
-    fi
-
     return 0
 }
 
-- 
1.5.4.5