[DLM] wait for config check during join [6/6]

Joining the lockspace should wait for the initial round of inter-node
config checks to complete before returning.  This way, if there's a
configuration mismatch between the joining node and the existing nodes,
the join can fail and return an error to the application.

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

4 files changed, 40 insertions, 2 deletions

diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index a8d6e993697c..03ba6c4fd5c2 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -472,6 +472,8 @@ struct dlm_ls {
 
         wait_queue_head_t       ls_uevent_wait; /* user part of join/leave */
         int                     ls_uevent_result;
+        struct completion       ls_members_done;
+        int                     ls_members_result;
 
         struct miscdevice       ls_device;
 
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index a3a50e67e4dd..c8f0c15ac166 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -197,13 +197,24 @@ static int do_uevent(struct dlm_ls *ls, int in)
         else
                 kobject_uevent(&ls->ls_kobj, KOBJ_OFFLINE);
 
+        log_debug(ls, "%s the lockspace group...", in ? "joining" : "leaving");
+
+        /* dlm_controld will see the uevent, do the necessary group management
+           and then write to sysfs to wake us */
+
         error = wait_event_interruptible(ls->ls_uevent_wait,
                         test_and_clear_bit(LSFL_UEVENT_WAIT, &ls->ls_flags));
+
+        log_debug(ls, "group event done %d %d", error, ls->ls_uevent_result);
+
         if (error)
                 goto out;
 
         error = ls->ls_uevent_result;
  out:
+        if (error)
+                log_error(ls, "group %s failed %d %d", in ? "join" : "leave",
+                          error, ls->ls_uevent_result);
         return error;
 }
 
@@ -490,6 +501,8 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
 
         init_waitqueue_head(&ls->ls_uevent_wait);
         ls->ls_uevent_result = 0;
+        init_completion(&ls->ls_members_done);
+        ls->ls_members_result = -1;
 
         ls->ls_recoverd_task = NULL;
         mutex_init(&ls->ls_recoverd_active);
@@ -540,10 +553,21 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         /* let kobject handle freeing of ls if there's an error */
         do_unreg = 1;
 
+        /* This uevent triggers dlm_controld in userspace to add us to the
+           group of nodes that are members of this lockspace (managed by the
+           cluster infrastructure.)  Once it's done that, it tells us who the
+           current lockspace members are (via configfs) and then tells the
+           lockspace to start running (via sysfs) in dlm_ls_start(). */
+
         error = do_uevent(ls, 1);
         if (error)
                 goto out_stop;
 
+        wait_for_completion(&ls->ls_members_done);
+        error = ls->ls_members_result;
+        if (error)
+                goto out_members;
+
         dlm_create_debug_file(ls);
 
         log_debug(ls, "join complete");
@@ -551,6 +575,10 @@ static int new_lockspace(char *name, int namelen, void **lockspace,
         *lockspace = ls;
         return 0;
 
+ out_members:
+        do_uevent(ls, 0);
+        dlm_clear_members(ls);
+        kfree(ls->ls_node_array);
  out_stop:
         dlm_recoverd_stop(ls);
  out_delist:
@@ -588,6 +616,8 @@ int dlm_new_lockspace(char *name, int namelen, void **lockspace,
         error = new_lockspace(name, namelen, lockspace, flags, lvblen);
         if (!error)
                 ls_count++;
+        else if (!ls_count)
+                threads_stop();
  out:
         mutex_unlock(&ls_lock);
         return error;
diff --git a/fs/dlm/member.c b/fs/dlm/member.c
index f08faec3d854..073599dced2a 100644
--- a/fs/dlm/member.c
+++ b/fs/dlm/member.c
@@ -233,6 +233,12 @@ int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
         *neg_out = neg;
 
         error = ping_members(ls);
+        if (!error || error == -EPROTO) {
+                /* new_lockspace() may be waiting to know if the config
+                   is good or bad */
+                ls->ls_members_result = error;
+                complete(&ls->ls_members_done);
+        }
         if (error)
                 goto out;
 
diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 6bfbd6153809..f71c23542f0f 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -90,7 +90,7 @@ static int check_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
                 log_error(ls, "version mismatch: %x nodeid %d: %x",
                           DLM_HEADER_MAJOR | DLM_HEADER_MINOR, nodeid,
                           rc->rc_header.h_version);
-                return -EINVAL;
+                return -EPROTO;
         }
 
         if (rf->rf_lvblen != ls->ls_lvblen ||
@@ -98,7 +98,7 @@ static int check_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
                 log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
                           ls->ls_lvblen, ls->ls_exflags,
                           nodeid, rf->rf_lvblen, rf->rf_lsflags);
-                return -EINVAL;
+                return -EPROTO;
         }
         return 0;
 }