diff options
| -rw-r--r-- | fs/notify/Kconfig | 13 | ||||
| -rw-r--r-- | fs/notify/Makefile | 2 | ||||
| -rw-r--r-- | fs/notify/fsnotify.c | 79 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 15 | ||||
| -rw-r--r-- | fs/notify/group.c | 198 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.c | 20 | ||||
| -rw-r--r-- | fs/notify/notification.c | 121 | ||||
| -rw-r--r-- | include/linux/fsnotify.h | 115 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 177 |
9 files changed, 705 insertions, 35 deletions
diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig index 50914d7303c..31dac7e3b0f 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 5a95b6010ce..db5467b5b58 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 00000000000..56bee0f10c3 --- /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 00000000000..c6a8bd47657 --- /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 00000000000..c6812953b96 --- /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 220c13f0d73..40b1cf914cc 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 00000000000..b8e9a87f8f5 --- /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); + diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 00fbd5b245c..6c9ebefdac8 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -13,6 +13,7 @@ #include <linux/dnotify.h> #include <linux/inotify.h> +#include <linux/fsnotify_backend.h> #include <linux/audit.h> /* @@ -35,6 +36,16 @@ static inline void fsnotify_d_move(struct dentry *entry) } /* + * fsnotify_link_count - inode's link count changed + */ +static inline void fsnotify_link_count(struct inode *inode) +{ + inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL); + + fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE); +} + +/* * fsnotify_move - file old_name at old_dir was moved to new_name at new_dir */ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, @@ -43,28 +54,47 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, { struct inode *source = moved->d_inode; u32 cookie = inotify_get_cookie(); + __u32 old_dir_mask = 0; + __u32 new_dir_mask = 0; - if (old_dir == new_dir) + if (old_dir == new_dir) { inode_dir_notify(old_dir, DN_RENAME); - else { + old_dir_mask = FS_DN_RENAME; + } else { inode_dir_notify(old_dir, DN_DELETE); + old_dir_mask = FS_DELETE; inode_dir_notify(new_dir, DN_CREATE); + new_dir_mask = FS_CREATE; } - if (isdir) + if (isdir) { isdir = IN_ISDIR; + old_dir_mask |= FS_IN_ISDIR; + new_dir_mask |= FS_IN_ISDIR; + } + + old_dir_mask |= FS_MOVED_FROM; + new_dir_mask |= FS_MOVED_TO; + inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name, source); inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name, source); + fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE); + fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE); + if (target) { inotify_inode_queue_event(target, IN_DELETE_SELF, 0, NULL, NULL); inotify_inode_is_dead(target); + + /* this is really a link_count change not a removal */ + fsnotify_link_count(target); } if (source) { inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL, NULL); + fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE); } audit_inode_child(new_name, moved, new_dir); } @@ -74,10 +104,12 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, */ static inline void fsnotify_nameremove(struct dentry *dentry, int isdir) { + __u32 mask = FS_DELETE; + if (isdir) - isdir = IN_ISDIR; + mask |= FS_IN_ISDIR; dnotify_parent(dentry, DN_DELETE); - inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name); + inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); } /* @@ -87,14 +119,8 @@ static inline void fsnotify_inoderemove(struct inode *inode) { inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL, NULL); inotify_inode_is_dead(inode); -} -/* - * fsnotify_link_count - inode's link count changed - */ -static inline void fsnotify_link_count(struct inode *inode) -{ - inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL); + fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE); } /* @@ -106,6 +132,8 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry) inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name, dentry->d_inode); audit_inode_child(dentry->d_name.name, dentry, inode); + + fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE); } /* @@ -120,6 +148,8 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct inode); fsnotify_link_count(inode); audit_inode_child(new_dentry->d_name.name, new_dentry, dir); + + fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE); } /* @@ -127,10 +157,14 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct */ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry) { + __u32 mask = (FS_CREATE | FS_IN_ISDIR); + struct inode *d_inode = dentry->d_inode; + inode_dir_notify(inode, DN_CREATE); - inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, - dentry->d_name.name, dentry->d_inode); + inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode); audit_inode_child(dentry->d_name.name, dentry, inode); + + fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE); } /* @@ -139,14 +173,16 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry) static inline void fsnotify_access(struct dentry *dentry) { struct inode *inode = dentry->d_inode; - u32 mask = IN_ACCESS; + __u32 mask = FS_ACCESS; if (S_ISDIR(inode->i_mode)) - mask |= IN_ISDIR; + mask |= FS_IN_ISDIR; dnotify_parent(dentry, DN_ACCESS); inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + + fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } /* @@ -155,14 +191,16 @@ static inline void fsnotify_access(struct dentry *dentry) static inline void fsnotify_modify(struct dentry *dentry) { struct inode *inode = dentry->d_inode; - u32 mask = IN_MODIFY; + __u32 mask = FS_MODIFY; if (S_ISDIR(inode->i_mode)) - mask |= IN_ISDIR; + mask |= FS_IN_ISDIR; dnotify_parent(dentry, DN_MODIFY); inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + + fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } /* @@ -171,13 +209,15 @@ static inline void fsnotify_modify(struct dentry *dentry) static inline void fsnotify_open(struct dentry *dentry) { struct inode *inode = dentry->d_inode; - u32 mask = IN_OPEN; + __u32 mask = FS_OPEN; if (S_ISDIR(inode->i_mode)) - mask |= IN_ISDIR; + mask |= FS_IN_ISDIR; inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + + fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } /* @@ -189,13 +229,15 @@ static inline void fsnotify_close(struct file *file) struct inode *inode = dentry->d_inode; const char *name = dentry->d_name.name; fmode_t mode = file->f_mode; - u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE; + __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE; if (S_ISDIR(inode->i_mode)) - mask |= IN_ISDIR; + mask |= FS_IN_ISDIR; inotify_dentry_parent_queue_event(dentry, mask, 0, name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + + fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE); } /* @@ -204,13 +246,15 @@ static inline void fsnotify_close(struct file *file) static inline void fsnotify_xattr(struct dentry *dentry) { struct inode *inode = dentry->d_inode; - u32 mask = IN_ATTRIB; + __u32 mask = FS_ATTRIB; if (S_ISDIR(inode->i_mode)) - mask |= IN_ISDIR; + mask |= FS_IN_ISDIR; inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + + fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } /* @@ -221,34 +265,34 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) { struct inode *inode = dentry->d_inode; int dn_mask = 0; - u32 in_mask = 0; + __u32 in_mask = 0; if (ia_valid & ATTR_UID) { - in_mask |= IN_ATTRIB; + in_mask |= FS_ATTRIB; dn_mask |= DN_ATTRIB; } if (ia_valid & ATTR_GID) { - in_mask |= IN_ATTRIB; + in_mask |= FS_ATTRIB; dn_mask |= DN_ATTRIB; } if (ia_valid & ATTR_SIZE) { - in_mask |= IN_MODIFY; + in_mask |= FS_MODIFY; dn_mask |= DN_MODIFY; } /* both times implies a utime(s) call */ if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) { - in_mask |= IN_ATTRIB; + in_mask |= FS_ATTRIB; dn_mask |= DN_ATTRIB; } else if (ia_valid & ATTR_ATIME) { - in_mask |= IN_ACCESS; + in_mask |= FS_ACCESS; dn_mask |= DN_ACCESS; } else if (ia_valid & ATTR_MTIME) { - in_mask |= IN_MODIFY; + in_mask |= FS_MODIFY; dn_mask |= DN_MODIFY; } if (ia_valid & ATTR_MODE) { - in_mask |= IN_ATTRIB; + in_mask |= FS_ATTRIB; dn_mask |= DN_ATTRIB; } @@ -256,14 +300,15 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) dnotify_parent(dentry, dn_mask); if (in_mask) { if (S_ISDIR(inode->i_mode)) - in_mask |= IN_ISDIR; + in_mask |= FS_IN_ISDIR; inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL); inotify_dentry_parent_queue_event(dentry, in_mask, 0, dentry->d_name.name); + fsnotify(inode, in_mask, inode, FSNOTIFY_EVENT_INODE); } } -#ifdef CONFIG_INOTIFY /* inotify helpers */ +#if defined(CONFIG_INOTIFY) || defined(CONFIG_FSNOTIFY) /* notify helpers */ /* * fsnotify_oldname_init - save off the old filename before we change it @@ -281,7 +326,7 @@ static inline void fsnotify_oldname_free(const char *old_name) kfree(old_name); } -#else /* CONFIG_INOTIFY */ +#else /* CONFIG_INOTIFY || CONFIG_FSNOTIFY */ static inline const char *fsnotify_oldname_init(const char *name) { diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h new file mode 100644 index 00000000000..1a55718b38a --- /dev/null +++ b/include/linux/fsnotify_backend.h @@ -0,0 +1,177 @@ +/* + * Filesystem access notification for Linux + * + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + */ + +#ifndef __LINUX_FSNOTIFY_BACKEND_H +#define __LINUX_FSNOTIFY_BACKEND_H + +#ifdef __KERNEL__ + +#include <linux/fs.h> /* struct inode */ +#include <linux/list.h> +#include <linux/path.h> /* struct path */ +#include <linux/spinlock.h> +#include <linux/types.h> + +#include <asm/atomic.h> + +/* + * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily + * convert between them. dnotify only needs conversion at watch creation + * so no perf loss there. fanotify isn't defined yet, so it can use the + * wholes if it needs more events. + */ +#define FS_ACCESS 0x00000001 /* File was accessed */ +#define FS_MODIFY 0x00000002 /* File was modified */ +#define FS_ATTRIB 0x00000004 /* Metadata changed */ +#define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */ +#define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */ +#define FS_OPEN 0x00000020 /* File was opened */ +#define FS_MOVED_FROM 0x00000040 /* File was moved from X */ +#define FS_MOVED_TO 0x00000080 /* File was moved to Y */ +#define FS_CREATE 0x00000100 /* Subfile was created */ +#define FS_DELETE 0x00000200 /* Subfile was deleted */ +#define FS_DELETE_SELF 0x00000400 /* Self was deleted */ +#define FS_MOVE_SELF 0x00000800 /* Self was moved */ + +#define FS_UNMOUNT 0x00002000 /* inode on umount fs */ +#define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */ +#define FS_IN_IGNORED 0x00008000 /* last inotify event here */ + +#define FS_IN_ISDIR 0x40000000 /* event occurred against dir */ +#define FS_IN_ONESHOT 0x80000000 /* only send event once */ + +#define FS_DN_RENAME 0x10000000 /* file renamed */ +#define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */ + +struct fsnotify_group; +struct fsnotify_event; + +/* + * Each group much define these ops. The fsnotify infrastructure will call + * these operations for each relevant group. + * + * handle_event - main call for a group to handle an fs event + * free_group_priv - called when a group refcnt hits 0 to clean up the private union + */ +struct fsnotify_ops { + int (*handle_event)(struct fsnotify_group *group, struct fsnotify_event *event); + void (*free_group_priv)(struct fsnotify_group *group); +}; + +/* + * A group is a "thing" that wants to receive notification about filesystem + * events. The mask holds the subset of event types this group cares about. + * refcnt on a group is up to the implementor and at any moment if it goes 0 + * everything will be cleaned up. + */ +struct fsnotify_group { + /* + * global list of all groups receiving events from fsnotify. + * anchored by fsnotify_groups and protected by either fsnotify_grp_mutex + * or fsnotify_grp_srcu depending on write vs read. + */ + struct list_head group_list; + + /* + * Defines all of the event types in which this group is interested. + * This mask is a bitwise OR of the FS_* events from above. Each time + * this mask changes for a group (if it changes) the correct functions + * must be called to update the global structures which indicate global + * interest in event types. + */ + __u32 mask; + + /* + * How the refcnt is used is up to each group. When the refcnt hits 0 + * fsnotify will clean up all of the resources associated with this group. + * As an example, the dnotify group will always have a refcnt=1 and that + * will never change. Inotify, on the other hand, has a group per + * inotify_init() and the refcnt will hit 0 only when that fd has been + * closed. + */ + atomic_t refcnt; /* things with interest in this group */ + unsigned int group_num; /* simply prevents accidental group collision */ + + const struct fsnotify_ops *ops; /* how this group handles things */ + + /* prevents double list_del of group_list. protected by global fsnotify_gr_mutex */ + bool on_group_list; + + /* groups can define private fields here or use the void *private */ + union { + void *private; + }; +}; + +/* + * all of the information about the original object we want to now send to + * a group. If you want to carry more info from the accessing task to the + * listener this structure is where you need to be adding fields. + */ +struct fsnotify_event { + spinlock_t lock; /* protection for the associated event_holder and private_list */ + /* to_tell may ONLY be dereferenced during handle_event(). */ + struct inode *to_tell; /* either the inode the event happened to or its parent */ + /* + * depending on the event type we should have either a path or inode + * We hold a reference on path, but NOT on inode. Since we have the ref on + * the path, it may be dereferenced at any point during this object's + * lifetime. That reference is dropped when this object's refcnt hits + * 0. If this event contains an inode instead of a path, the inode may + * ONLY be used during handle_event(). + */ + union { + struct path path; + struct inode *inode; + }; +/* when calling fsnotify tell it if the data is a path or inode */ +#define FSNOTIFY_EVENT_NONE 0 +#define FSNOTIFY_EVENT_PATH 1 +#define FSNOTIFY_EVENT_INODE 2 +#define FSNOTIFY_EVENT_FILE 3 + int data_type; /* which of the above union we have */ + atomic_t refcnt; /* how many groups still are using/need to send this event */ + __u32 mask; /* the type of access, bitwise OR for FS_* event types */ +}; + +#ifdef CONFIG_FSNOTIFY + +/* called from the vfs helpers */ + +/* main fsnotify call to send events */ +extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is); + + +/* called from fsnotify listeners, such as fanotify or dnotify */ + +/* must call when a group changes its ->mask */ +extern void fsnotify_recalc_global_mask(void); +/* get a reference to an existing or create a new group */ +extern struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, + __u32 mask, + const struct fsnotify_ops *ops); +/* drop reference on a group from fsnotify_obtain_group */ +extern void fsnotify_put_group(struct fsnotify_group *group); + +/* take a reference to an event */ +extern void fsnotify_get_event(struct fsnotify_event *event); +extern void fsnotify_put_event(struct fsnotify_event *event); +/* find private data previously attached to an event */ +extern struct fsnotify_event_private_data *fsnotify_get_priv_from_event(struct fsnotify_group *group, + struct fsnotify_event *event); + +/* put here because inotify does some weird stuff when destroying watches */ +extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, + void *data, int data_is); +#else + +static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is) +{} +#endif /* CONFIG_FSNOTIFY */ + +#endif /* __KERNEL __ */ + +#endif /* __LINUX_FSNOTIFY_BACKEND_H */ |