[Ocfs2-devel] [PATCH 7/7] Don't allow cluster_stack changes if FS are mounted

[Goldwyn Rodrigues <rgoldwyn@suse.de>]

---
 fs/ocfs2/dlmglue.c   |  3 ++-
 fs/ocfs2/stackglue.c | 18 ++++++++++++++++++
 fs/ocfs2/stackglue.h |  3 +++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index f2d48c8..65b4280 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3023,7 +3023,7 @@ local:
 	ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
 
 	osb->cconn = conn;
-
+	ocfs2_inc_mount_count();
 	status = 0;
 bail:
 	if (status < 0) {
@@ -3058,6 +3058,7 @@ void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
 
 	ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
 	osb->cconn = NULL;
+	ocfs2_dec_mount_count();
 
 	ocfs2_dlm_shutdown_debug(osb);
 }
diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index 4dd732b..e352a2e 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -41,6 +41,7 @@ static DEFINE_SPINLOCK(ocfs2_stack_lock);
 static LIST_HEAD(ocfs2_stack_list);
 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
+static atomic_t mount_count = ATOMIC_INIT(0);
 
 /*
  * The stack currently in use.  If not null, active_stack->sp_count > 0,
@@ -417,6 +418,18 @@ int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 }
 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 
+void ocfs2_inc_mount_count()
+{
+	atomic_inc(&mount_count);
+}
+EXPORT_SYMBOL_GPL(ocfs2_inc_mount_count);
+
+void ocfs2_dec_mount_count()
+{
+	atomic_dec(&mount_count);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dec_mount_count);
+
 /*
  * Leave the group for this filesystem.  This is executed by a userspace
  * program (stored in ocfs2_hb_ctl_path).
@@ -569,6 +582,11 @@ static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 	size_t len = count;
 	ssize_t ret;
 
+	if (atomic_read(&mount_count) > 0) {
+		printk(KERN_NOTICE "ocfs2_stackglue: Cannot set cluster_stack when filesystems are mounted.\n");
+		return -EINVAL;
+	}
+
 	if (len == 0)
 		return len;
 
diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h
index d3a54df..da4a913 100644
--- a/fs/ocfs2/stackglue.h
+++ b/fs/ocfs2/stackglue.h
@@ -293,6 +293,9 @@ int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 
 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto);
 
+void ocfs2_inc_mount_count(void);
+void ocfs2_dec_mount_count(void);
+
 
 /* Used by stack plugins */
 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
-- 
1.8.1.4


-- 
Goldwyn