dlm: allow multiple lockspace creates
Add a count for lockspace create and release so that create can
be called multiple times to use the lockspace from different places.
Also add the new flag DLM_LSFL_NEWEXCL to create a lockspace with
the previous behavior of returning -EEXIST if the lockspace already
exists.
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 34f14a1..6542110 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2006-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
@@ -340,10 +340,15 @@
return error;
}
-static int create_misc_device(struct dlm_ls *ls, char *name)
+static int dlm_device_register(struct dlm_ls *ls, char *name)
{
int error, len;
+ /* The device is already registered. This happens when the
+ lockspace is created multiple times from userspace. */
+ if (ls->ls_device.name)
+ return 0;
+
error = -ENOMEM;
len = strlen(name) + strlen(name_prefix) + 2;
ls->ls_device.name = kzalloc(len, GFP_KERNEL);
@@ -363,6 +368,22 @@
return error;
}
+int dlm_device_deregister(struct dlm_ls *ls)
+{
+ int error;
+
+ /* The device is not registered. This happens when the lockspace
+ was never used from userspace, or when device_create_lockspace()
+ calls dlm_release_lockspace() after the register fails. */
+ if (!ls->ls_device.name)
+ return 0;
+
+ error = misc_deregister(&ls->ls_device);
+ if (!error)
+ kfree(ls->ls_device.name);
+ return error;
+}
+
static int device_user_purge(struct dlm_user_proc *proc,
struct dlm_purge_params *params)
{
@@ -397,7 +418,7 @@
if (!ls)
return -ENOENT;
- error = create_misc_device(ls, params->name);
+ error = dlm_device_register(ls, params->name);
dlm_put_lockspace(ls);
if (error)
@@ -421,31 +442,22 @@
if (!ls)
return -ENOENT;
- /* Deregister the misc device first, so we don't have
- * a device that's not attached to a lockspace. If
- * dlm_release_lockspace fails then we can recreate it
- */
- error = misc_deregister(&ls->ls_device);
- if (error) {
- dlm_put_lockspace(ls);
- goto out;
- }
- kfree(ls->ls_device.name);
-
if (params->flags & DLM_USER_LSFLG_FORCEFREE)
force = 2;
lockspace = ls->ls_local_handle;
-
- /* dlm_release_lockspace waits for references to go to zero,
- so all processes will need to close their device for the ls
- before the release will procede */
-
dlm_put_lockspace(ls);
+
+ /* The final dlm_release_lockspace waits for references to go to
+ zero, so all processes will need to close their device for the
+ ls before the release will proceed. release also calls the
+ device_deregister above. Converting a positive return value
+ from release to zero means that userspace won't know when its
+ release was the final one, but it shouldn't need to know. */
+
error = dlm_release_lockspace(lockspace, force);
- if (error)
- create_misc_device(ls, ls->ls_name);
- out:
+ if (error > 0)
+ error = 0;
return error;
}