fs: dlm: fix memory leak when fenced

I got some kmemleak report when a node was fenced. The user space tool
dlm_controld will therefore run some rmdir() in dlm configfs which was
triggering some memleaks. This patch stores the sps and cms attributes
which stores some handling for subdirectories of the configfs cluster
entry and free them if they get released as the parent directory gets
freed.

unreferenced object 0xffff88810d9e3e00 (size 192):
  comm "dlm_controld", pid 342, jiffies 4294698126 (age 55438.801s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 73 70 61 63 65 73 00 00  ........spaces..
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000db8b640b>] make_cluster+0x5d/0x360
    [<000000006a571db4>] configfs_mkdir+0x274/0x730
    [<00000000b094501c>] vfs_mkdir+0x27e/0x340
    [<0000000058b0adaf>] do_mkdirat+0xff/0x1b0
    [<00000000d1ffd156>] do_syscall_64+0x40/0x80
    [<00000000ab1408c8>] entry_SYSCALL_64_after_hwframe+0x44/0xae
unreferenced object 0xffff88810d9e3a00 (size 192):
  comm "dlm_controld", pid 342, jiffies 4294698126 (age 55438.801s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 63 6f 6d 6d 73 00 00 00  ........comms...
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000a7ef6ad2>] make_cluster+0x82/0x360
    [<000000006a571db4>] configfs_mkdir+0x274/0x730
    [<00000000b094501c>] vfs_mkdir+0x27e/0x340
    [<0000000058b0adaf>] do_mkdirat+0xff/0x1b0
    [<00000000d1ffd156>] do_syscall_64+0x40/0x80
    [<00000000ab1408c8>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

Author: Alexander Aring

fs/dlm/config.c

@@ -80,6 +80,9 @@ struct dlm_cluster {
 	unsigned int cl_new_rsb_count;
 	unsigned int cl_recover_callbacks;
 	char cl_cluster_name[DLM_LOCKSPACE_LEN];
+
+	struct dlm_spaces *sps;
+	struct dlm_comms *cms;
 };
 
 static struct dlm_cluster *config_item_to_cluster(struct config_item *i)
@@ -410,6 +413,9 @@ static struct config_group *make_cluster(struct config_group *g,
 	if (!cl || !sps || !cms)
 		goto fail;
 
+	cl->sps = sps;
+	cl->cms = cms;
+
 	config_group_init_type_name(&cl->group, name, &cluster_type);
 	config_group_init_type_name(&sps->ss_group, "spaces", &spaces_type);
 	config_group_init_type_name(&cms->cs_group, "comms", &comms_type);
@@ -459,6 +465,9 @@ static void drop_cluster(struct config_group *g, struct config_item *i)
 static void release_cluster(struct config_item *i)
 {
 	struct dlm_cluster *cl = config_item_to_cluster(i);
+
+	kfree(cl->sps);
+	kfree(cl->cms);
 	kfree(cl);
 }