[GFS2] No lock_nolock

This patch merges the lock_nolock module into GFS2 itself. As well as removing
some of the overhead of the module, it also means that its now impossible to
build GFS2 without a lock module (which would be a pointless thing to do
anyway).

We also plan to merge lock_dlm into GFS2 in the future, but that is a more
tricky task, and will therefore be a separate patch.

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

1 files changed, 50 insertions, 2 deletions

diff --git a/fs/gfs2/locking.c b/fs/gfs2/locking.c
index 663fee728783..a4a367aa5cc1 100644
--- a/fs/gfs2/locking.c
+++ b/fs/gfs2/locking.c
@@ -23,12 +23,54 @@ struct lmh_wrapper {
         const struct lm_lockops *lw_ops;
 };
 
+static int nolock_mount(char *table_name, char *host_data,
+                        lm_callback_t cb, void *cb_data,
+                        unsigned int min_lvb_size, int flags,
+                        struct lm_lockstruct *lockstruct,
+                        struct kobject *fskobj);
+
 /* List of registered low-level locking protocols.  A file system selects one
    of them by name at mount time, e.g. lock_nolock, lock_dlm. */
 
+static const struct lm_lockops nolock_ops = {
+        .lm_proto_name = "lock_nolock",
+        .lm_mount = nolock_mount,
+};
+
+static struct lmh_wrapper nolock_proto  = {
+        .lw_list = LIST_HEAD_INIT(nolock_proto.lw_list),
+        .lw_ops = &nolock_ops,
+};
+
 static LIST_HEAD(lmh_list);
 static DEFINE_MUTEX(lmh_lock);
 
+static int nolock_mount(char *table_name, char *host_data,
+                        lm_callback_t cb, void *cb_data,
+                        unsigned int min_lvb_size, int flags,
+                        struct lm_lockstruct *lockstruct,
+                        struct kobject *fskobj)
+{
+        char *c;
+        unsigned int jid;
+
+        c = strstr(host_data, "jid=");
+        if (!c)
+                jid = 0;
+        else {
+                c += 4;
+                sscanf(c, "%u", &jid);
+        }
+
+        lockstruct->ls_jid = jid;
+        lockstruct->ls_first = 1;
+        lockstruct->ls_lvb_size = min_lvb_size;
+        lockstruct->ls_ops = &nolock_ops;
+        lockstruct->ls_flags = LM_LSFLAG_LOCAL;
+
+        return 0;
+}
+
 /**
  * gfs2_register_lockproto - Register a low-level locking protocol
  * @proto: the protocol definition
@@ -116,9 +158,13 @@ int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
         int try = 0;
         int error, found;
 
+
 retry:
         mutex_lock(&lmh_lock);
 
+        if (list_empty(&nolock_proto.lw_list))
+                list_add(&lmh_list, &nolock_proto.lw_list);
+
         found = 0;
         list_for_each_entry(lw, &lmh_list, lw_list) {
                 if (!strcmp(lw->lw_ops->lm_proto_name, proto_name)) {
@@ -139,7 +185,8 @@ retry:
                 goto out;
         }
 
-        if (!try_module_get(lw->lw_ops->lm_owner)) {
+        if (lw->lw_ops->lm_owner &&
+            !try_module_get(lw->lw_ops->lm_owner)) {
                 try = 0;
                 mutex_unlock(&lmh_lock);
                 msleep(1000);
@@ -158,7 +205,8 @@ out:
 void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct)
 {
         mutex_lock(&lmh_lock);
-        lockstruct->ls_ops->lm_unmount(lockstruct->ls_lockspace);
+        if (lockstruct->ls_ops->lm_unmount)
+                lockstruct->ls_ops->lm_unmount(lockstruct->ls_lockspace);
         if (lockstruct->ls_ops->lm_owner)
                 module_put(lockstruct->ls_ops->lm_owner);
         mutex_unlock(&lmh_lock);