X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fgfs2%2Flocking.c;fp=fs%2Fgfs2%2Flocking.c;h=bc4abcdcd602a968fd3bb3534bb4365f3f243302;hb=76828883507a47dae78837ab5dec5a5b4513c667;hp=0000000000000000000000000000000000000000;hpb=64ba3f394c830ec48a1c31b53dcae312c56f1604;p=linux-2.6.git

diff --git a/fs/gfs2/locking.c b/fs/gfs2/locking.c
new file mode 100644
index 000000000..bc4abcdcd
--- /dev/null
+++ b/fs/gfs2/locking.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 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
+ * of the GNU General Public License version 2.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <linux/lm_interface.h>
+
+struct lmh_wrapper {
+	struct list_head lw_list;
+	const struct lm_lockops *lw_ops;
+};
+
+/* 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 LIST_HEAD(lmh_list);
+static DEFINE_MUTEX(lmh_lock);
+
+/**
+ * gfs2_register_lockproto - Register a low-level locking protocol
+ * @proto: the protocol definition
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+int gfs2_register_lockproto(const struct lm_lockops *proto)
+{
+	struct lmh_wrapper *lw;
+
+	mutex_lock(&lmh_lock);
+
+	list_for_each_entry(lw, &lmh_list, lw_list) {
+		if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
+			mutex_unlock(&lmh_lock);
+			printk(KERN_INFO "GFS2: protocol %s already exists\n",
+			       proto->lm_proto_name);
+			return -EEXIST;
+		}
+	}
+
+	lw = kzalloc(sizeof(struct lmh_wrapper), GFP_KERNEL);
+	if (!lw) {
+		mutex_unlock(&lmh_lock);
+		return -ENOMEM;
+	}
+
+	lw->lw_ops = proto;
+	list_add(&lw->lw_list, &lmh_list);
+
+	mutex_unlock(&lmh_lock);
+
+	return 0;
+}
+
+/**
+ * gfs2_unregister_lockproto - Unregister a low-level locking protocol
+ * @proto: the protocol definition
+ *
+ */
+
+void gfs2_unregister_lockproto(const struct lm_lockops *proto)
+{
+	struct lmh_wrapper *lw;
+
+	mutex_lock(&lmh_lock);
+
+	list_for_each_entry(lw, &lmh_list, lw_list) {
+		if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
+			list_del(&lw->lw_list);
+			mutex_unlock(&lmh_lock);
+			kfree(lw);
+			return;
+		}
+	}
+
+	mutex_unlock(&lmh_lock);
+
+	printk(KERN_WARNING "GFS2: can't unregister lock protocol %s\n",
+	       proto->lm_proto_name);
+}
+
+/**
+ * gfs2_mount_lockproto - Mount a lock protocol
+ * @proto_name - the name of the protocol
+ * @table_name - the name of the lock space
+ * @host_data - data specific to this host
+ * @cb - the callback to the code using the lock module
+ * @sdp - The GFS2 superblock
+ * @min_lvb_size - the mininum LVB size that the caller can deal with
+ * @flags - LM_MFLAG_*
+ * @lockstruct - a structure returned describing the mount
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+int gfs2_mount_lockproto(char *proto_name, 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)
+{
+	struct lmh_wrapper *lw = NULL;
+	int try = 0;
+	int error, found;
+
+retry:
+	mutex_lock(&lmh_lock);
+
+	found = 0;
+	list_for_each_entry(lw, &lmh_list, lw_list) {
+		if (!strcmp(lw->lw_ops->lm_proto_name, proto_name)) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		if (!try && capable(CAP_SYS_MODULE)) {
+			try = 1;
+			mutex_unlock(&lmh_lock);
+			request_module(proto_name);
+			goto retry;
+		}
+		printk(KERN_INFO "GFS2: can't find protocol %s\n", proto_name);
+		error = -ENOENT;
+		goto out;
+	}
+
+	if (!try_module_get(lw->lw_ops->lm_owner)) {
+		try = 0;
+		mutex_unlock(&lmh_lock);
+		msleep(1000);
+		goto retry;
+	}
+
+	error = lw->lw_ops->lm_mount(table_name, host_data, cb, cb_data,
+				     min_lvb_size, flags, lockstruct, fskobj);
+	if (error)
+		module_put(lw->lw_ops->lm_owner);
+out:
+	mutex_unlock(&lmh_lock);
+	return error;
+}
+
+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_owner)
+		module_put(lockstruct->ls_ops->lm_owner);
+	mutex_unlock(&lmh_lock);
+}
+
+/**
+ * gfs2_withdraw_lockproto - abnormally unmount a lock module
+ * @lockstruct: the lockstruct passed into mount
+ *
+ */
+
+void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct)
+{
+	mutex_lock(&lmh_lock);
+	lockstruct->ls_ops->lm_withdraw(lockstruct->ls_lockspace);
+	if (lockstruct->ls_ops->lm_owner)
+		module_put(lockstruct->ls_ops->lm_owner);
+	mutex_unlock(&lmh_lock);
+}
+
+EXPORT_SYMBOL_GPL(gfs2_register_lockproto);
+EXPORT_SYMBOL_GPL(gfs2_unregister_lockproto);
+EXPORT_SYMBOL_GPL(gfs2_withdraw_lockproto);
+EXPORT_SYMBOL_GPL(gfs2_mount_lockproto);
+EXPORT_SYMBOL_GPL(gfs2_unmount_lockproto);