1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/lvfs/fsfilt.c b/drivers/staging/lustre/lustre/lvfs/fsfilt.c
new file mode 100644
index 000000000000..064445cbdb57
--- /dev/null
+++ b/drivers/staging/lustre/lustre/lvfs/fsfilt.c
@@ -0,0 +1,138 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+
+#define DEBUG_SUBSYSTEM S_FILTER
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/module.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/libcfs/libcfs.h>
+#include <lustre_fsfilt.h>
+
+LIST_HEAD(fsfilt_types);
+
+static struct fsfilt_operations *fsfilt_search_type(const char *type)
+{
+	struct fsfilt_operations *found;
+	struct list_head *p;
+
+	list_for_each(p, &fsfilt_types) {
+		found = list_entry(p, struct fsfilt_operations, fs_list);
+		if (!strcmp(found->fs_type, type)) {
+			return found;
+		}
+	}
+	return NULL;
+}
+
+int fsfilt_register_ops(struct fsfilt_operations *fs_ops)
+{
+	struct fsfilt_operations *found;
+
+	/* lock fsfilt_types list */
+	if ((found = fsfilt_search_type(fs_ops->fs_type))) {
+		if (found != fs_ops) {
+			CERROR("different operations for type %s\n",
+			       fs_ops->fs_type);
+			/* unlock fsfilt_types list */
+			RETURN(-EEXIST);
+		}
+	} else {
+		try_module_get(THIS_MODULE);
+		list_add(&fs_ops->fs_list, &fsfilt_types);
+	}
+
+	/* unlock fsfilt_types list */
+	return 0;
+}
+EXPORT_SYMBOL(fsfilt_register_ops);
+
+void fsfilt_unregister_ops(struct fsfilt_operations *fs_ops)
+{
+	struct list_head *p;
+
+	/* lock fsfilt_types list */
+	list_for_each(p, &fsfilt_types) {
+		struct fsfilt_operations *found;
+
+		found = list_entry(p, typeof(*found), fs_list);
+		if (found == fs_ops) {
+			list_del(p);
+			module_put(THIS_MODULE);
+			break;
+		}
+	}
+	/* unlock fsfilt_types list */
+}
+EXPORT_SYMBOL(fsfilt_unregister_ops);
+
+struct fsfilt_operations *fsfilt_get_ops(const char *type)
+{
+	struct fsfilt_operations *fs_ops;
+
+	/* lock fsfilt_types list */
+	if (!(fs_ops = fsfilt_search_type(type))) {
+		char name[32];
+		int rc;
+
+		snprintf(name, sizeof(name) - 1, "fsfilt_%s", type);
+		name[sizeof(name) - 1] = '\0';
+
+		if (!(rc = request_module("%s", name))) {
+			fs_ops = fsfilt_search_type(type);
+			CDEBUG(D_INFO, "Loaded module '%s'\n", name);
+			if (!fs_ops)
+				rc = -ENOENT;
+		}
+
+		if (rc) {
+			CERROR("Can't find %s interface\n", name);
+			RETURN(ERR_PTR(rc < 0 ? rc : -rc));
+			/* unlock fsfilt_types list */
+		}
+	}
+	try_module_get(fs_ops->fs_owner);
+	/* unlock fsfilt_types list */
+
+	return fs_ops;
+}
+EXPORT_SYMBOL(fsfilt_get_ops);
+
+void fsfilt_put_ops(struct fsfilt_operations *fs_ops)
+{
+	module_put(fs_ops->fs_owner);
+}
+EXPORT_SYMBOL(fsfilt_put_ops);