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authorJoel Becker <joel.becker@oracle.com>2005-12-15 14:29:43 -0800
committerJoel Becker <joel.becker@oracle.com>2006-01-03 11:45:28 -0800
commit7063fbf2261194f72ee75afca67b3b38b554b5fa (patch)
tree7bfe4eeab8ce784b767cf30886623d456c384718 /include/linux
parent88026842b0a760145aa71d69e74fbc9ec118ca44 (diff)
[PATCH] configfs: User-driven configuration filesystem
Configfs, a file system for userspace-driven kernel object configuration. The OCFS2 stack makes extensive use of this for propagation of cluster configuration information into kernel. Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/configfs.h205
1 files changed, 205 insertions, 0 deletions
diff --git a/include/linux/configfs.h b/include/linux/configfs.h
new file mode 100644
index 000000000000..acffb8c9073a
--- /dev/null
+++ b/include/linux/configfs.h
@@ -0,0 +1,205 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * configfs.h - definitions for the device driver filesystem
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ * Based on sysfs:
+ * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
+ *
+ * Based on kobject.h:
+ * Copyright (c) 2002-2003 Patrick Mochel
+ * Copyright (c) 2002-2003 Open Source Development Labs
+ *
+ * configfs Copyright (C) 2005 Oracle. All rights reserved.
+ *
+ * Please read Documentation/filesystems/configfs.txt before using the
+ * configfs interface, ESPECIALLY the parts about reference counts and
+ * item destructors.
+ */
+
+#ifndef _CONFIGFS_H_
+#define _CONFIGFS_H_
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/kref.h>
+
+#include <asm/atomic.h>
+#include <asm/semaphore.h>
+
+#define CONFIGFS_ITEM_NAME_LEN 20
+
+struct module;
+
+struct configfs_item_operations;
+struct configfs_group_operations;
+struct configfs_attribute;
+struct configfs_subsystem;
+
+struct config_item {
+ char *ci_name;
+ char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
+ struct kref ci_kref;
+ struct list_head ci_entry;
+ struct config_item *ci_parent;
+ struct config_group *ci_group;
+ struct config_item_type *ci_type;
+ struct dentry *ci_dentry;
+};
+
+extern int config_item_set_name(struct config_item *, const char *, ...);
+
+static inline char *config_item_name(struct config_item * item)
+{
+ return item->ci_name;
+}
+
+extern void config_item_init(struct config_item *);
+extern void config_item_init_type_name(struct config_item *item,
+ const char *name,
+ struct config_item_type *type);
+extern void config_item_cleanup(struct config_item *);
+
+extern struct config_item * config_item_get(struct config_item *);
+extern void config_item_put(struct config_item *);
+
+struct config_item_type {
+ struct module *ct_owner;
+ struct configfs_item_operations *ct_item_ops;
+ struct configfs_group_operations *ct_group_ops;
+ struct configfs_attribute **ct_attrs;
+};
+
+
+/**
+ * group - a group of config_items of a specific type, belonging
+ * to a specific subsystem.
+ */
+
+struct config_group {
+ struct config_item cg_item;
+ struct list_head cg_children;
+ struct configfs_subsystem *cg_subsys;
+ struct config_group **default_groups;
+};
+
+
+extern void config_group_init(struct config_group *group);
+extern void config_group_init_type_name(struct config_group *group,
+ const char *name,
+ struct config_item_type *type);
+
+
+static inline struct config_group *to_config_group(struct config_item *item)
+{
+ return item ? container_of(item,struct config_group,cg_item) : NULL;
+}
+
+static inline struct config_group *config_group_get(struct config_group *group)
+{
+ return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
+}
+
+static inline void config_group_put(struct config_group *group)
+{
+ config_item_put(&group->cg_item);
+}
+
+extern struct config_item *config_group_find_obj(struct config_group *, const char *);
+
+
+struct configfs_attribute {
+ char *ca_name;
+ struct module *ca_owner;
+ mode_t ca_mode;
+};
+
+
+/*
+ * If allow_link() exists, the item can symlink(2) out to other
+ * items. If the item is a group, it may support mkdir(2).
+ * Groups supply one of make_group() and make_item(). If the
+ * group supports make_group(), one can create group children. If it
+ * supports make_item(), one can create config_item children. If it has
+ * default_groups on group->default_groups, it has automatically created
+ * group children. default_groups may coexist alongsize make_group() or
+ * make_item(), but if the group wishes to have only default_groups
+ * children (disallowing mkdir(2)), it need not provide either function.
+ * If the group has commit(), it supports pending and commited (active)
+ * items.
+ */
+struct configfs_item_operations {
+ void (*release)(struct config_item *);
+ ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
+ ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
+ int (*allow_link)(struct config_item *src, struct config_item *target);
+ int (*drop_link)(struct config_item *src, struct config_item *target);
+};
+
+struct configfs_group_operations {
+ struct config_item *(*make_item)(struct config_group *group, const char *name);
+ struct config_group *(*make_group)(struct config_group *group, const char *name);
+ int (*commit_item)(struct config_item *item);
+ void (*drop_item)(struct config_group *group, struct config_item *item);
+};
+
+
+
+/**
+ * Use these macros to make defining attributes easier. See include/linux/device.h
+ * for examples..
+ */
+
+#if 0
+#define __ATTR(_name,_mode,_show,_store) { \
+ .attr = {.ca_name = __stringify(_name), .ca_mode = _mode, .ca_owner = THIS_MODULE }, \
+ .show = _show, \
+ .store = _store, \
+}
+
+#define __ATTR_RO(_name) { \
+ .attr = { .ca_name = __stringify(_name), .ca_mode = 0444, .ca_owner = THIS_MODULE }, \
+ .show = _name##_show, \
+}
+
+#define __ATTR_NULL { .attr = { .name = NULL } }
+
+#define attr_name(_attr) (_attr).attr.name
+#endif
+
+
+struct configfs_subsystem {
+ struct config_group su_group;
+ struct semaphore su_sem;
+};
+
+static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
+{
+ return group ?
+ container_of(group, struct configfs_subsystem, su_group) :
+ NULL;
+}
+
+int configfs_register_subsystem(struct configfs_subsystem *subsys);
+void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
+
+#endif /* __KERNEL__ */
+
+#endif /* _CONFIGFS_H_ */