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-rw-r--r--fs/notify/Kconfig13
-rw-r--r--fs/notify/Makefile2
-rw-r--r--fs/notify/fsnotify.c79
-rw-r--r--fs/notify/fsnotify.h15
-rw-r--r--fs/notify/group.c198
-rw-r--r--fs/notify/inotify/inotify.c20
-rw-r--r--fs/notify/notification.c121
7 files changed, 448 insertions, 0 deletions
diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig
index 50914d7..31dac7e 100644
--- a/fs/notify/Kconfig
+++ b/fs/notify/Kconfig
@@ -1,2 +1,15 @@
+config FSNOTIFY
+ bool "Filesystem notification backend"
+ default y
+ ---help---
+ fsnotify is a backend for filesystem notification. fsnotify does
+ not provide any userspace interface but does provide the basis
+ needed for other notification schemes such as dnotify, inotify,
+ and fanotify.
+
+ Say Y here to enable fsnotify suport.
+
+ If unsure, say Y.
+
source "fs/notify/dnotify/Kconfig"
source "fs/notify/inotify/Kconfig"
diff --git a/fs/notify/Makefile b/fs/notify/Makefile
index 5a95b60..db5467b 100644
--- a/fs/notify/Makefile
+++ b/fs/notify/Makefile
@@ -1,2 +1,4 @@
+obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o
+
obj-y += dnotify/
obj-y += inotify/
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
new file mode 100644
index 0000000..56bee0f
--- /dev/null
+++ b/fs/notify/fsnotify.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * 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, 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; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/dcache.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/srcu.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+/*
+ * This is the main call to fsnotify. The VFS calls into hook specific functions
+ * in linux/fsnotify.h. Those functions then in turn call here. Here will call
+ * out to all of the registered fsnotify_group. Those groups can then use the
+ * notification event in whatever means they feel necessary.
+ */
+void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is)
+{
+ struct fsnotify_group *group;
+ struct fsnotify_event *event = NULL;
+ int idx;
+
+ if (list_empty(&fsnotify_groups))
+ return;
+
+ if (!(mask & fsnotify_mask))
+ return;
+
+ /*
+ * SRCU!! the groups list is very very much read only and the path is
+ * very hot. The VAST majority of events are not going to need to do
+ * anything other than walk the list so it's crazy to pre-allocate.
+ */
+ idx = srcu_read_lock(&fsnotify_grp_srcu);
+ list_for_each_entry_rcu(group, &fsnotify_groups, group_list) {
+ if (mask & group->mask) {
+ if (!event) {
+ event = fsnotify_create_event(to_tell, mask, data, data_is);
+ /* shit, we OOM'd and now we can't tell, maybe
+ * someday someone else will want to do something
+ * here */
+ if (!event)
+ break;
+ }
+ group->ops->handle_event(group, event);
+ }
+ }
+ srcu_read_unlock(&fsnotify_grp_srcu, idx);
+ /*
+ * fsnotify_create_event() took a reference so the event can't be cleaned
+ * up while we are still trying to add it to lists, drop that one.
+ */
+ if (event)
+ fsnotify_put_event(event);
+}
+EXPORT_SYMBOL_GPL(fsnotify);
+
+static __init int fsnotify_init(void)
+{
+ return init_srcu_struct(&fsnotify_grp_srcu);
+}
+subsys_initcall(fsnotify_init);
diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h
new file mode 100644
index 0000000..c6a8bd4
--- /dev/null
+++ b/fs/notify/fsnotify.h
@@ -0,0 +1,15 @@
+#ifndef __FS_NOTIFY_FSNOTIFY_H_
+#define __FS_NOTIFY_FSNOTIFY_H_
+
+#include <linux/list.h>
+#include <linux/fsnotify.h>
+#include <linux/srcu.h>
+#include <linux/types.h>
+
+/* protects reads of fsnotify_groups */
+extern struct srcu_struct fsnotify_grp_srcu;
+/* all groups which receive fsnotify events */
+extern struct list_head fsnotify_groups;
+/* all bitwise OR of all event types (FS_*) for all fsnotify_groups */
+extern __u32 fsnotify_mask;
+#endif /* __FS_NOTIFY_FSNOTIFY_H_ */
diff --git a/fs/notify/group.c b/fs/notify/group.c
new file mode 100644
index 0000000..c681295
--- /dev/null
+++ b/fs/notify/group.c
@@ -0,0 +1,198 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * 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, 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; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+#include <linux/rculist.h>
+#include <linux/wait.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+#include <asm/atomic.h>
+
+/* protects writes to fsnotify_groups and fsnotify_mask */
+static DEFINE_MUTEX(fsnotify_grp_mutex);
+/* protects reads while running the fsnotify_groups list */
+struct srcu_struct fsnotify_grp_srcu;
+/* all groups registered to receive filesystem notifications */
+LIST_HEAD(fsnotify_groups);
+/* bitwise OR of all events (FS_*) interesting to some group on this system */
+__u32 fsnotify_mask;
+
+/*
+ * When a new group registers or changes it's set of interesting events
+ * this function updates the fsnotify_mask to contain all interesting events
+ */
+void fsnotify_recalc_global_mask(void)
+{
+ struct fsnotify_group *group;
+ __u32 mask = 0;
+ int idx;
+
+ idx = srcu_read_lock(&fsnotify_grp_srcu);
+ list_for_each_entry_rcu(group, &fsnotify_groups, group_list)
+ mask |= group->mask;
+ srcu_read_unlock(&fsnotify_grp_srcu, idx);
+ fsnotify_mask = mask;
+}
+
+/*
+ * Take a reference to a group so things found under the fsnotify_grp_mutex
+ * can't get freed under us
+ */
+static void fsnotify_get_group(struct fsnotify_group *group)
+{
+ atomic_inc(&group->refcnt);
+}
+
+/*
+ * Final freeing of a group
+ */
+static void fsnotify_destroy_group(struct fsnotify_group *group)
+{
+ if (group->ops->free_group_priv)
+ group->ops->free_group_priv(group);
+
+ kfree(group);
+}
+
+/*
+ * Remove this group from the global list of groups that will get events
+ * this can be done even if there are still references and things still using
+ * this group. This just stops the group from getting new events.
+ */
+static void __fsnotify_evict_group(struct fsnotify_group *group)
+{
+ BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
+
+ if (group->on_group_list)
+ list_del_rcu(&group->group_list);
+ group->on_group_list = 0;
+}
+
+/*
+ * Called when a group is no longer interested in getting events. This can be
+ * used if a group is misbehaving or if for some reason a group should no longer
+ * get any filesystem events.
+ */
+void fsnotify_evict_group(struct fsnotify_group *group)
+{
+ mutex_lock(&fsnotify_grp_mutex);
+ __fsnotify_evict_group(group);
+ mutex_unlock(&fsnotify_grp_mutex);
+}
+
+/*
+ * Drop a reference to a group. Free it if it's through.
+ */
+void fsnotify_put_group(struct fsnotify_group *group)
+{
+ if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex))
+ return;
+
+ /*
+ * OK, now we know that there's no other users *and* we hold mutex,
+ * so no new references will appear
+ */
+ __fsnotify_evict_group(group);
+
+ /*
+ * now it's off the list, so the only thing we might care about is
+ * srcu access....
+ */
+ mutex_unlock(&fsnotify_grp_mutex);
+ synchronize_srcu(&fsnotify_grp_srcu);
+
+ /* and now it is really dead. _Nothing_ could be seeing it */
+ fsnotify_recalc_global_mask();
+ fsnotify_destroy_group(group);
+}
+
+/*
+ * Simply run the fsnotify_groups list and find a group which matches
+ * the given parameters. If a group is found we take a reference to that
+ * group.
+ */
+static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask,
+ const struct fsnotify_ops *ops)
+{
+ struct fsnotify_group *group_iter;
+ struct fsnotify_group *group = NULL;
+
+ BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
+
+ list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) {
+ if (group_iter->group_num == group_num) {
+ if ((group_iter->mask == mask) &&
+ (group_iter->ops == ops)) {
+ fsnotify_get_group(group_iter);
+ group = group_iter;
+ } else
+ group = ERR_PTR(-EEXIST);
+ }
+ }
+ return group;
+}
+
+/*
+ * Either finds an existing group which matches the group_num, mask, and ops or
+ * creates a new group and adds it to the global group list. In either case we
+ * take a reference for the group returned.
+ */
+struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
+ const struct fsnotify_ops *ops)
+{
+ struct fsnotify_group *group, *tgroup;
+
+ /* very low use, simpler locking if we just always alloc */
+ group = kmalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
+ if (!group)
+ return ERR_PTR(-ENOMEM);
+
+ atomic_set(&group->refcnt, 1);
+
+ group->on_group_list = 0;
+ group->group_num = group_num;
+ group->mask = mask;
+
+ group->ops = ops;
+
+ mutex_lock(&fsnotify_grp_mutex);
+ tgroup = fsnotify_find_group(group_num, mask, ops);
+ if (tgroup) {
+ /* group already exists */
+ mutex_unlock(&fsnotify_grp_mutex);
+ /* destroy the new one we made */
+ fsnotify_put_group(group);
+ return tgroup;
+ }
+
+ /* group not found, add a new one */
+ list_add_rcu(&group->group_list, &fsnotify_groups);
+ group->on_group_list = 1;
+
+ mutex_unlock(&fsnotify_grp_mutex);
+
+ if (mask)
+ fsnotify_recalc_global_mask();
+
+ return group;
+}
diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c
index 220c13f..40b1cf9 100644
--- a/fs/notify/inotify/inotify.c
+++ b/fs/notify/inotify/inotify.c
@@ -32,6 +32,7 @@
#include <linux/list.h>
#include <linux/writeback.h>
#include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
static atomic_t inotify_cookie;
@@ -905,6 +906,25 @@ EXPORT_SYMBOL_GPL(inotify_rm_watch);
*/
static int __init inotify_setup(void)
{
+ BUILD_BUG_ON(IN_ACCESS != FS_ACCESS);
+ BUILD_BUG_ON(IN_MODIFY != FS_MODIFY);
+ BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB);
+ BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE);
+ BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
+ BUILD_BUG_ON(IN_OPEN != FS_OPEN);
+ BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM);
+ BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO);
+ BUILD_BUG_ON(IN_CREATE != FS_CREATE);
+ BUILD_BUG_ON(IN_DELETE != FS_DELETE);
+ BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF);
+ BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF);
+ BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW);
+
+ BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT);
+ BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR);
+ BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED);
+ BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
+
atomic_set(&inotify_cookie, 0);
return 0;
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
new file mode 100644
index 0000000..b8e9a87
--- /dev/null
+++ b/fs/notify/notification.c
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * 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, 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; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mount.h>
+#include <linux/mutex.h>
+#include <linux/namei.h>
+#include <linux/path.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <asm/atomic.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+static struct kmem_cache *fsnotify_event_cachep;
+
+void fsnotify_get_event(struct fsnotify_event *event)
+{
+ atomic_inc(&event->refcnt);
+}
+
+void fsnotify_put_event(struct fsnotify_event *event)
+{
+ if (!event)
+ return;
+
+ if (atomic_dec_and_test(&event->refcnt)) {
+ if (event->data_type == FSNOTIFY_EVENT_PATH)
+ path_put(&event->path);
+
+ kmem_cache_free(fsnotify_event_cachep, event);
+ }
+}
+
+/*
+ * Allocate a new event which will be sent to each group's handle_event function
+ * if the group was interested in this particular event.
+ */
+struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
+ void *data, int data_type)
+{
+ struct fsnotify_event *event;
+
+ event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);
+ if (!event)
+ return NULL;
+
+ atomic_set(&event->refcnt, 1);
+
+ spin_lock_init(&event->lock);
+
+ event->path.dentry = NULL;
+ event->path.mnt = NULL;
+ event->inode = NULL;
+
+ event->to_tell = to_tell;
+
+ switch (data_type) {
+ case FSNOTIFY_EVENT_FILE: {
+ struct file *file = data;
+ struct path *path = &file->f_path;
+ event->path.dentry = path->dentry;
+ event->path.mnt = path->mnt;
+ path_get(&event->path);
+ event->data_type = FSNOTIFY_EVENT_PATH;
+ break;
+ }
+ case FSNOTIFY_EVENT_PATH: {
+ struct path *path = data;
+ event->path.dentry = path->dentry;
+ event->path.mnt = path->mnt;
+ path_get(&event->path);
+ event->data_type = FSNOTIFY_EVENT_PATH;
+ break;
+ }
+ case FSNOTIFY_EVENT_INODE:
+ event->inode = data;
+ event->data_type = FSNOTIFY_EVENT_INODE;
+ break;
+ case FSNOTIFY_EVENT_NONE:
+ event->inode = NULL;
+ event->path.dentry = NULL;
+ event->path.mnt = NULL;
+ break;
+ default:
+ BUG();
+ }
+
+ event->mask = mask;
+
+ return event;
+}
+
+__init int fsnotify_notification_init(void)
+{
+ fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC);
+
+ return 0;
+}
+subsys_initcall(fsnotify_notification_init);
+
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