From 90586523eb4b349806887c62ee70685a49415124 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:20 -0400 Subject: fsnotify: unified filesystem notification backend 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. fsnotify can be extended to be the backend for inotify or the upcoming fanotify. fsnotify provides a mechanism for "groups" to register for some set of filesystem events and to then deliver those events to those groups for processing. fsnotify has a number of benefits, the first being actually shrinking the size of an inode. Before fsnotify to support both dnotify and inotify an inode had unsigned long i_dnotify_mask; /* Directory notify events */ struct dnotify_struct *i_dnotify; /* for directory notifications */ struct list_head inotify_watches; /* watches on this inode */ struct mutex inotify_mutex; /* protects the watches list But with fsnotify this same functionallity (and more) is done with just __u32 i_fsnotify_mask; /* all events for this inode */ struct hlist_head i_fsnotify_mark_entries; /* marks on this inode */ That's right, inotify, dnotify, and fanotify all in 64 bits. We used that much space just in inotify_watches alone, before this patch set. fsnotify object lifetime and locking is MUCH better than what we have today. inotify locking is incredibly complex. See 8f7b0ba1c8539 as an example of what's been busted since inception. inotify needs to know internal semantics of superblock destruction and unmounting to function. The inode pinning and vfs contortions are horrible. no fsnotify implementers do allocation under locks. This means things like f04b30de3 which (due to an overabundance of caution) changes GFP_KERNEL to GFP_NOFS can be reverted. There are no longer any allocation rules when using or implementing your own fsnotify listener. fsnotify paves the way for fanotify. In brief fanotify is a notification mechanism that delivers the lisener both an 'event' and an open file descriptor to the object in question. This means that fanotify is pathname agnostic. Some on lkml may not care for the original companies or users that pushed for TALPA, but fanotify was designed with flexibility and input for other users in mind. The readahead group expressed interest in fanotify as it could be used to profile disk access on boot without breaking the audit system. The desktop search groups have also expressed interest in fanotify as it solves a number of the race conditions and problems present with managing inotify when more than a limited number of specific files are of interest. fanotify can provide for a userspace access control system which makes it a clean interface for AV vendors to hook without trying to do binary patching on the syscall table, LSM, and everywhere else they do their things today. With this patch series fanotify can be implemented in less than 1200 lines of easy to review code. Almost all of which is the socket based user interface. This patch series builds fsnotify to the point that it can implement dnotify and inotify_user. Patches exist and will be sent soon after acceptance to finish the in kernel inotify conversion (audit) and implement fanotify. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/Kconfig | 13 +++ fs/notify/Makefile | 2 + fs/notify/fsnotify.c | 79 ++++++++++++++++++ fs/notify/fsnotify.h | 15 ++++ fs/notify/group.c | 198 ++++++++++++++++++++++++++++++++++++++++++++ fs/notify/inotify/inotify.c | 20 +++++ fs/notify/notification.c | 121 +++++++++++++++++++++++++++ 7 files changed, 448 insertions(+) create mode 100644 fs/notify/fsnotify.c create mode 100644 fs/notify/fsnotify.h create mode 100644 fs/notify/group.c create mode 100644 fs/notify/notification.c (limited to 'fs') 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 + * + * 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 +#include +#include +#include +#include + +#include +#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 +#include +#include +#include + +/* 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 + * + * 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 +#include +#include +#include +#include +#include + +#include +#include "fsnotify.h" + +#include + +/* 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 #include #include +#include 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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#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); + -- cgit v1.2.2 From 3be25f49b9d6a97eae9bcb96d3292072b7658bd8 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:26 -0400 Subject: fsnotify: add marks to inodes so groups can interpret how to handle those inodes This patch creates a way for fsnotify groups to attach marks to inodes. These marks have little meaning to the generic fsnotify infrastructure and thus their meaning should be interpreted by the group that attached them to the inode's list. dnotify and inotify will make use of these markings to indicate which inodes are of interest to their respective groups. But this implementation has the useful property that in the future other listeners could actually use the marks for the exact opposite reason, aka to indicate which inodes it had NO interest in. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/inode.c | 9 ++ fs/notify/Makefile | 2 +- fs/notify/fsnotify.c | 13 ++ fs/notify/fsnotify.h | 5 + fs/notify/group.c | 49 +++++++- fs/notify/inode_mark.c | 329 +++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 405 insertions(+), 2 deletions(-) create mode 100644 fs/notify/inode_mark.c (limited to 'fs') diff --git a/fs/inode.c b/fs/inode.c index bca0c618fdb..54c63ce3de2 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -189,6 +190,10 @@ struct inode *inode_init_always(struct super_block *sb, struct inode *inode) inode->i_private = NULL; inode->i_mapping = mapping; +#ifdef CONFIG_FSNOTIFY + inode->i_fsnotify_mask = 0; +#endif + return inode; out_free_security: @@ -221,6 +226,7 @@ void destroy_inode(struct inode *inode) BUG_ON(inode_has_buffers(inode)); ima_inode_free(inode); security_inode_free(inode); + fsnotify_inode_delete(inode); if (inode->i_sb->s_op->destroy_inode) inode->i_sb->s_op->destroy_inode(inode); else @@ -252,6 +258,9 @@ void inode_init_once(struct inode *inode) INIT_LIST_HEAD(&inode->inotify_watches); mutex_init(&inode->inotify_mutex); #endif +#ifdef CONFIG_FSNOTIFY + INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries); +#endif } EXPORT_SYMBOL(inode_init_once); diff --git a/fs/notify/Makefile b/fs/notify/Makefile index db5467b5b58..0922cc826c4 100644 --- a/fs/notify/Makefile +++ b/fs/notify/Makefile @@ -1,4 +1,4 @@ -obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o +obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o obj-y += dnotify/ obj-y += inotify/ diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 56bee0f10c3..d5654629c65 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -25,6 +25,15 @@ #include #include "fsnotify.h" +/* + * Clear all of the marks on an inode when it is being evicted from core + */ +void __fsnotify_inode_delete(struct inode *inode) +{ + fsnotify_clear_marks_by_inode(inode); +} +EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); + /* * 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 @@ -43,6 +52,8 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is) if (!(mask & fsnotify_mask)) return; + if (!(mask & to_tell->i_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 @@ -51,6 +62,8 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is) idx = srcu_read_lock(&fsnotify_grp_srcu); list_for_each_entry_rcu(group, &fsnotify_groups, group_list) { if (mask & group->mask) { + if (!group->ops->should_send_event(group, to_tell, mask)) + continue; if (!event) { event = fsnotify_create_event(to_tell, mask, data, data_is); /* shit, we OOM'd and now we can't tell, maybe diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index c6a8bd47657..8ebcbe893c9 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -12,4 +12,9 @@ extern struct srcu_struct fsnotify_grp_srcu; extern struct list_head fsnotify_groups; /* all bitwise OR of all event types (FS_*) for all fsnotify_groups */ extern __u32 fsnotify_mask; + +/* final kfree of a group */ +extern void fsnotify_final_destroy_group(struct fsnotify_group *group); +/* run the list of all marks associated with inode and flag them to be freed */ +extern void fsnotify_clear_marks_by_inode(struct inode *inode); #endif /* __FS_NOTIFY_FSNOTIFY_H_ */ diff --git a/fs/notify/group.c b/fs/notify/group.c index c6812953b96..a29d2fa6792 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -54,6 +54,29 @@ void fsnotify_recalc_global_mask(void) fsnotify_mask = mask; } +/* + * Update the group->mask by running all of the marks associated with this + * group and finding the bitwise | of all of the mark->mask. If we change + * the group->mask we need to update the global mask of events interesting + * to the system. + */ +void fsnotify_recalc_group_mask(struct fsnotify_group *group) +{ + __u32 mask = 0; + __u32 old_mask = group->mask; + struct fsnotify_mark_entry *entry; + + spin_lock(&group->mark_lock); + list_for_each_entry(entry, &group->mark_entries, g_list) + mask |= entry->mask; + spin_unlock(&group->mark_lock); + + group->mask = mask; + + if (old_mask != mask) + fsnotify_recalc_global_mask(); +} + /* * Take a reference to a group so things found under the fsnotify_grp_mutex * can't get freed under us @@ -66,7 +89,7 @@ static void fsnotify_get_group(struct fsnotify_group *group) /* * Final freeing of a group */ -static void fsnotify_destroy_group(struct fsnotify_group *group) +void fsnotify_final_destroy_group(struct fsnotify_group *group) { if (group->ops->free_group_priv) group->ops->free_group_priv(group); @@ -74,6 +97,24 @@ static void fsnotify_destroy_group(struct fsnotify_group *group) kfree(group); } +/* + * Trying to get rid of a group. We need to first get rid of any outstanding + * allocations and then free the group. Remember that fsnotify_clear_marks_by_group + * could miss marks that are being freed by inode and those marks could still + * hold a reference to this group (via group->num_marks) If we get into that + * situtation, the fsnotify_final_destroy_group will get called when that final + * mark is freed. + */ +static void fsnotify_destroy_group(struct fsnotify_group *group) +{ + /* clear all inode mark entries for this group */ + fsnotify_clear_marks_by_group(group); + + /* past the point of no return, matches the initial value of 1 */ + if (atomic_dec_and_test(&group->num_marks)) + fsnotify_final_destroy_group(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 @@ -173,6 +214,10 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, group->group_num = group_num; group->mask = mask; + spin_lock_init(&group->mark_lock); + atomic_set(&group->num_marks, 0); + INIT_LIST_HEAD(&group->mark_entries); + group->ops = ops; mutex_lock(&fsnotify_grp_mutex); @@ -188,6 +233,8 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, /* group not found, add a new one */ list_add_rcu(&group->group_list, &fsnotify_groups); group->on_group_list = 1; + /* being on the fsnotify_groups list holds one num_marks */ + atomic_inc(&group->num_marks); mutex_unlock(&fsnotify_grp_mutex); diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c new file mode 100644 index 00000000000..cdc15414697 --- /dev/null +++ b/fs/notify/inode_mark.c @@ -0,0 +1,329 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris + * + * 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. + */ + +/* + * fsnotify inode mark locking/lifetime/and refcnting + * + * REFCNT: + * The mark->refcnt tells how many "things" in the kernel currently are + * referencing this object. The object typically will live inside the kernel + * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task + * which can find this object holding the appropriete locks, can take a reference + * and the object itself is guarenteed to survive until the reference is dropped. + * + * LOCKING: + * There are 3 spinlocks involved with fsnotify inode marks and they MUST + * be taken in order as follows: + * + * entry->lock + * group->mark_lock + * inode->i_lock + * + * entry->lock protects 2 things, entry->group and entry->inode. You must hold + * that lock to dereference either of these things (they could be NULL even with + * the lock) + * + * group->mark_lock protects the mark_entries list anchored inside a given group + * and each entry is hooked via the g_list. It also sorta protects the + * free_g_list, which when used is anchored by a private list on the stack of the + * task which held the group->mark_lock. + * + * inode->i_lock protects the i_fsnotify_mark_entries list anchored inside a + * given inode and each entry is hooked via the i_list. (and sorta the + * free_i_list) + * + * + * LIFETIME: + * Inode marks survive between when they are added to an inode and when their + * refcnt==0. + * + * The inode mark can be cleared for a number of different reasons including: + * - The inode is unlinked for the last time. (fsnotify_inode_remove) + * - The inode is being evicted from cache. (fsnotify_inode_delete) + * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) + * - Something explicitly requests that it be removed. (fsnotify_destroy_mark_by_entry) + * - The fsnotify_group associated with the mark is going away and all such marks + * need to be cleaned up. (fsnotify_clear_marks_by_group) + * + * Worst case we are given an inode and need to clean up all the marks on that + * inode. We take i_lock and walk the i_fsnotify_mark_entries safely. For each + * mark on the list we take a reference (so the mark can't disappear under us). + * We remove that mark form the inode's list of marks and we add this mark to a + * private list anchored on the stack using i_free_list; At this point we no + * longer fear anything finding the mark using the inode's list of marks. + * + * We can safely and locklessly run the private list on the stack of everything + * we just unattached from the original inode. For each mark on the private list + * we grab the mark-> and can thus dereference mark->group and mark->inode. If + * we see the group and inode are not NULL we take those locks. Now holding all + * 3 locks we can completely remove the mark from other tasks finding it in the + * future. Remember, 10 things might already be referencing this mark, but they + * better be holding a ref. We drop our reference we took before we unhooked it + * from the inode. When the ref hits 0 we can free the mark. + * + * Very similarly for freeing by group, except we use free_g_list. + * + * This has the very interesting property of being able to run concurrently with + * any (or all) other directions. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include "fsnotify.h" + +void fsnotify_get_mark(struct fsnotify_mark_entry *entry) +{ + atomic_inc(&entry->refcnt); +} + +void fsnotify_put_mark(struct fsnotify_mark_entry *entry) +{ + if (atomic_dec_and_test(&entry->refcnt)) + entry->free_mark(entry); +} + +/* + * Recalculate the mask of events relevant to a given inode locked. + */ +static void fsnotify_recalc_inode_mask_locked(struct inode *inode) +{ + struct fsnotify_mark_entry *entry; + struct hlist_node *pos; + __u32 new_mask = 0; + + assert_spin_locked(&inode->i_lock); + + hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) + new_mask |= entry->mask; + inode->i_fsnotify_mask = new_mask; +} + +/* + * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types + * any notifier is interested in hearing for this inode. + */ +void fsnotify_recalc_inode_mask(struct inode *inode) +{ + spin_lock(&inode->i_lock); + fsnotify_recalc_inode_mask_locked(inode); + spin_unlock(&inode->i_lock); +} + +/* + * Any time a mark is getting freed we end up here. + * The caller had better be holding a reference to this mark so we don't actually + * do the final put under the entry->lock + */ +void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) +{ + struct fsnotify_group *group; + struct inode *inode; + + spin_lock(&entry->lock); + + group = entry->group; + inode = entry->inode; + + BUG_ON(group && !inode); + BUG_ON(!group && inode); + + /* if !group something else already marked this to die */ + if (!group) { + spin_unlock(&entry->lock); + return; + } + + /* 1 from caller and 1 for being on i_list/g_list */ + BUG_ON(atomic_read(&entry->refcnt) < 2); + + spin_lock(&group->mark_lock); + spin_lock(&inode->i_lock); + + hlist_del_init(&entry->i_list); + entry->inode = NULL; + + list_del_init(&entry->g_list); + entry->group = NULL; + + fsnotify_put_mark(entry); /* for i_list and g_list */ + + /* + * this mark is now off the inode->i_fsnotify_mark_entries list and we + * hold the inode->i_lock, so this is the perfect time to update the + * inode->i_fsnotify_mask + */ + fsnotify_recalc_inode_mask_locked(inode); + + spin_unlock(&inode->i_lock); + spin_unlock(&group->mark_lock); + spin_unlock(&entry->lock); + + /* + * Some groups like to know that marks are being freed. This is a + * callback to the group function to let it know that this entry + * is being freed. + */ + group->ops->freeing_mark(entry, group); + + /* + * it's possible that this group tried to destroy itself, but this + * this mark was simultaneously being freed by inode. If that's the + * case, we finish freeing the group here. + */ + if (unlikely(atomic_dec_and_test(&group->num_marks))) + fsnotify_final_destroy_group(group); +} + +/* + * Given a group, destroy all of the marks associated with that group. + */ +void fsnotify_clear_marks_by_group(struct fsnotify_group *group) +{ + struct fsnotify_mark_entry *lentry, *entry; + LIST_HEAD(free_list); + + spin_lock(&group->mark_lock); + list_for_each_entry_safe(entry, lentry, &group->mark_entries, g_list) { + list_add(&entry->free_g_list, &free_list); + list_del_init(&entry->g_list); + fsnotify_get_mark(entry); + } + spin_unlock(&group->mark_lock); + + list_for_each_entry_safe(entry, lentry, &free_list, free_g_list) { + fsnotify_destroy_mark_by_entry(entry); + fsnotify_put_mark(entry); + } +} + +/* + * Given an inode, destroy all of the marks associated with that inode. + */ +void fsnotify_clear_marks_by_inode(struct inode *inode) +{ + struct fsnotify_mark_entry *entry, *lentry; + struct hlist_node *pos, *n; + LIST_HEAD(free_list); + + spin_lock(&inode->i_lock); + hlist_for_each_entry_safe(entry, pos, n, &inode->i_fsnotify_mark_entries, i_list) { + list_add(&entry->free_i_list, &free_list); + hlist_del_init(&entry->i_list); + fsnotify_get_mark(entry); + } + spin_unlock(&inode->i_lock); + + list_for_each_entry_safe(entry, lentry, &free_list, free_i_list) { + fsnotify_destroy_mark_by_entry(entry); + fsnotify_put_mark(entry); + } +} + +/* + * given a group and inode, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL + */ +struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group, + struct inode *inode) +{ + struct fsnotify_mark_entry *entry; + struct hlist_node *pos; + + assert_spin_locked(&inode->i_lock); + + hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) { + if (entry->group == group) { + fsnotify_get_mark(entry); + return entry; + } + } + return NULL; +} + +/* + * Nothing fancy, just initialize lists and locks and counters. + */ +void fsnotify_init_mark(struct fsnotify_mark_entry *entry, + void (*free_mark)(struct fsnotify_mark_entry *entry)) + +{ + spin_lock_init(&entry->lock); + atomic_set(&entry->refcnt, 1); + INIT_HLIST_NODE(&entry->i_list); + entry->group = NULL; + entry->mask = 0; + entry->inode = NULL; + entry->free_mark = free_mark; +} + +/* + * Attach an initialized mark entry to a given group and inode. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which group and for which inodes. + */ +int fsnotify_add_mark(struct fsnotify_mark_entry *entry, + struct fsnotify_group *group, struct inode *inode) +{ + struct fsnotify_mark_entry *lentry; + int ret = 0; + + /* + * LOCKING ORDER!!!! + * entry->lock + * group->mark_lock + * inode->i_lock + */ + spin_lock(&entry->lock); + spin_lock(&group->mark_lock); + spin_lock(&inode->i_lock); + + entry->group = group; + entry->inode = inode; + + lentry = fsnotify_find_mark_entry(group, inode); + if (!lentry) { + hlist_add_head(&entry->i_list, &inode->i_fsnotify_mark_entries); + list_add(&entry->g_list, &group->mark_entries); + + fsnotify_get_mark(entry); /* for i_list and g_list */ + + atomic_inc(&group->num_marks); + + fsnotify_recalc_inode_mask_locked(inode); + } + + spin_unlock(&inode->i_lock); + spin_unlock(&group->mark_lock); + spin_unlock(&entry->lock); + + if (lentry) { + ret = -EEXIST; + fsnotify_put_mark(lentry); + } + + return ret; +} -- cgit v1.2.2 From c28f7e56e9d95fb531dc3be8df2e7f52bee76d21 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:29 -0400 Subject: fsnotify: parent event notification inotify and dnotify both use a similar parent notification mechanism. We add a generic parent notification mechanism to fsnotify for both of these to use. This new machanism also adds the dentry flag optimization which exists for inotify to dnotify. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/fsnotify.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/notify/fsnotify.h | 5 +++ fs/notify/inode_mark.c | 17 ++++++++++ 3 files changed, 113 insertions(+) (limited to 'fs') diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index d5654629c65..7fc760067a6 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -34,6 +34,97 @@ void __fsnotify_inode_delete(struct inode *inode) } EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); +/* + * Given an inode, first check if we care what happens to our children. Inotify + * and dnotify both tell their parents about events. If we care about any event + * on a child we run all of our children and set a dentry flag saying that the + * parent cares. Thus when an event happens on a child it can quickly tell if + * if there is a need to find a parent and send the event to the parent. + */ +void __fsnotify_update_child_dentry_flags(struct inode *inode) +{ + struct dentry *alias; + int watched; + + if (!S_ISDIR(inode->i_mode)) + return; + + /* determine if the children should tell inode about their events */ + watched = fsnotify_inode_watches_children(inode); + + spin_lock(&dcache_lock); + /* run all of the dentries associated with this inode. Since this is a + * directory, there damn well better only be one item on this list */ + list_for_each_entry(alias, &inode->i_dentry, d_alias) { + struct dentry *child; + + /* run all of the children of the original inode and fix their + * d_flags to indicate parental interest (their parent is the + * original inode) */ + list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { + if (!child->d_inode) + continue; + + spin_lock(&child->d_lock); + if (watched) + child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; + else + child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; + spin_unlock(&child->d_lock); + } + } + spin_unlock(&dcache_lock); +} + +/* Notify this dentry's parent about a child's events. */ +void __fsnotify_parent(struct dentry *dentry, __u32 mask) +{ + struct dentry *parent; + struct inode *p_inode; + bool send = false; + bool should_update_children = false; + + if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) + return; + + spin_lock(&dentry->d_lock); + parent = dentry->d_parent; + p_inode = parent->d_inode; + + if (fsnotify_inode_watches_children(p_inode)) { + if (p_inode->i_fsnotify_mask & mask) { + dget(parent); + send = true; + } + } else { + /* + * The parent doesn't care about events on it's children but + * at least one child thought it did. We need to run all the + * children and update their d_flags to let them know p_inode + * doesn't care about them any more. + */ + dget(parent); + should_update_children = true; + } + + spin_unlock(&dentry->d_lock); + + if (send) { + /* we are notifying a parent so come up with the new mask which + * specifies these are events which came from a child. */ + mask |= FS_EVENT_ON_CHILD; + + fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE); + dput(parent); + } + + if (unlikely(should_update_children)) { + __fsnotify_update_child_dentry_flags(p_inode); + dput(parent); + } +} +EXPORT_SYMBOL_GPL(__fsnotify_parent); + /* * 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 diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 8ebcbe893c9..83b8ec0a8ec 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -17,4 +17,9 @@ extern __u32 fsnotify_mask; extern void fsnotify_final_destroy_group(struct fsnotify_group *group); /* run the list of all marks associated with inode and flag them to be freed */ extern void fsnotify_clear_marks_by_inode(struct inode *inode); +/* + * update the dentry->d_flags of all of inode's children to indicate if inode cares + * about events that happen to its children. + */ +extern void __fsnotify_update_child_dentry_flags(struct inode *inode); #endif /* __FS_NOTIFY_FSNOTIFY_H_ */ diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index cdc15414697..a39534845b2 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -131,6 +131,8 @@ void fsnotify_recalc_inode_mask(struct inode *inode) spin_lock(&inode->i_lock); fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); + + __fsnotify_update_child_dentry_flags(inode); } /* @@ -189,6 +191,19 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) */ group->ops->freeing_mark(entry, group); + /* + * __fsnotify_update_child_dentry_flags(inode); + * + * I really want to call that, but we can't, we have no idea if the inode + * still exists the second we drop the entry->lock. + * + * The next time an event arrive to this inode from one of it's children + * __fsnotify_parent will see that the inode doesn't care about it's + * children and will update all of these flags then. So really this + * is just a lazy update (and could be a perf win...) + */ + + /* * it's possible that this group tried to destroy itself, but this * this mark was simultaneously being freed by inode. If that's the @@ -323,6 +338,8 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry, if (lentry) { ret = -EEXIST; fsnotify_put_mark(lentry); + } else { + __fsnotify_update_child_dentry_flags(inode); } return ret; -- cgit v1.2.2 From 3c5119c05d624f95f4967d16b38c9624b816bdb9 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:33 -0400 Subject: dnotify: reimplement dnotify using fsnotify Reimplement dnotify using fsnotify. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/dnotify/Kconfig | 1 + fs/notify/dnotify/dnotify.c | 469 ++++++++++++++++++++++++++++++++++---------- 2 files changed, 363 insertions(+), 107 deletions(-) (limited to 'fs') diff --git a/fs/notify/dnotify/Kconfig b/fs/notify/dnotify/Kconfig index 26adf5dfa64..904ff8d5405 100644 --- a/fs/notify/dnotify/Kconfig +++ b/fs/notify/dnotify/Kconfig @@ -1,5 +1,6 @@ config DNOTIFY bool "Dnotify support" + depends on FSNOTIFY default y help Dnotify is a directory-based per-fd file change notification system diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index b0aa2cde80b..d9d80f502c6 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -3,6 +3,9 @@ * * Copyright (C) 2000,2001,2002 Stephen Rothwell * + * Copyright (C) 2009 Eric Paris + * dnotify was largly rewritten to use the new fsnotify infrastructure + * * 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 @@ -21,24 +24,178 @@ #include #include #include +#include int dir_notify_enable __read_mostly = 1; -static struct kmem_cache *dn_cache __read_mostly; +static struct kmem_cache *dnotify_struct_cache __read_mostly; +static struct kmem_cache *dnotify_mark_entry_cache __read_mostly; +static struct fsnotify_group *dnotify_group __read_mostly; +static DEFINE_MUTEX(dnotify_mark_mutex); + +/* + * dnotify will attach one of these to each inode (i_fsnotify_mark_entries) which + * is being watched by dnotify. If multiple userspace applications are watching + * the same directory with dnotify their information is chained in dn + */ +struct dnotify_mark_entry { + struct fsnotify_mark_entry fsn_entry; + struct dnotify_struct *dn; +}; -static void redo_inode_mask(struct inode *inode) +/* + * When a process starts or stops watching an inode the set of events which + * dnotify cares about for that inode may change. This function runs the + * list of everything receiving dnotify events about this directory and calculates + * the set of all those events. After it updates what dnotify is interested in + * it calls the fsnotify function so it can update the set of all events relevant + * to this inode. + */ +static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) { - unsigned long new_mask; + __u32 new_mask, old_mask; struct dnotify_struct *dn; + struct dnotify_mark_entry *dnentry = container_of(entry, + struct dnotify_mark_entry, + fsn_entry); + + assert_spin_locked(&entry->lock); + old_mask = entry->mask; new_mask = 0; - for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next) - new_mask |= dn->dn_mask & ~DN_MULTISHOT; - inode->i_dnotify_mask = new_mask; + for (dn = dnentry->dn; dn != NULL; dn = dn->dn_next) + new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT); + entry->mask = new_mask; + + if (old_mask == new_mask) + return; + + if (entry->inode) + fsnotify_recalc_inode_mask(entry->inode); } +/* + * Mains fsnotify call where events are delivered to dnotify. + * Find the dnotify mark on the relevant inode, run the list of dnotify structs + * on that mark and determine which of them has expressed interest in receiving + * events of this type. When found send the correct process and signal and + * destroy the dnotify struct if it was not registered to receive multiple + * events. + */ +static int dnotify_handle_event(struct fsnotify_group *group, + struct fsnotify_event *event) +{ + struct fsnotify_mark_entry *entry = NULL; + struct dnotify_mark_entry *dnentry; + struct inode *to_tell; + struct dnotify_struct *dn; + struct dnotify_struct **prev; + struct fown_struct *fown; + + to_tell = event->to_tell; + + spin_lock(&to_tell->i_lock); + entry = fsnotify_find_mark_entry(group, to_tell); + spin_unlock(&to_tell->i_lock); + + /* unlikely since we alreay passed dnotify_should_send_event() */ + if (unlikely(!entry)) + return 0; + dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + + spin_lock(&entry->lock); + prev = &dnentry->dn; + while ((dn = *prev) != NULL) { + if ((dn->dn_mask & event->mask) == 0) { + prev = &dn->dn_next; + continue; + } + fown = &dn->dn_filp->f_owner; + send_sigio(fown, dn->dn_fd, POLL_MSG); + if (dn->dn_mask & FS_DN_MULTISHOT) + prev = &dn->dn_next; + else { + *prev = dn->dn_next; + kmem_cache_free(dnotify_struct_cache, dn); + dnotify_recalc_inode_mask(entry); + } + } + + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); + + return 0; +} + +/* + * Given an inode and mask determine if dnotify would be interested in sending + * userspace notification for that pair. + */ +static bool dnotify_should_send_event(struct fsnotify_group *group, + struct inode *inode, __u32 mask) +{ + struct fsnotify_mark_entry *entry; + bool send; + + /* !dir_notify_enable should never get here, don't waste time checking + if (!dir_notify_enable) + return 0; */ + + /* not a dir, dnotify doesn't care */ + if (!S_ISDIR(inode->i_mode)) + return false; + + spin_lock(&inode->i_lock); + entry = fsnotify_find_mark_entry(group, inode); + spin_unlock(&inode->i_lock); + + /* no mark means no dnotify watch */ + if (!entry) + return false; + + spin_lock(&entry->lock); + send = (mask & entry->mask) ? true : false; + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ + + return send; +} + +static void dnotify_freeing_mark(struct fsnotify_mark_entry *entry, + struct fsnotify_group *group) +{ + /* dnotify doesn't care than an inode is on the way out */ +} + +static void dnotify_free_mark(struct fsnotify_mark_entry *entry) +{ + struct dnotify_mark_entry *dnentry = container_of(entry, + struct dnotify_mark_entry, + fsn_entry); + + BUG_ON(dnentry->dn); + + kmem_cache_free(dnotify_mark_entry_cache, dnentry); +} + +static struct fsnotify_ops dnotify_fsnotify_ops = { + .handle_event = dnotify_handle_event, + .should_send_event = dnotify_should_send_event, + .free_group_priv = NULL, + .freeing_mark = dnotify_freeing_mark, +}; + +/* + * Called every time a file is closed. Looks first for a dnotify mark on the + * inode. If one is found run all of the ->dn entries attached to that + * mark for one relevant to this process closing the file and remove that + * dnotify_struct. If that was the last dnotify_struct also remove the + * fsnotify_mark_entry. + */ void dnotify_flush(struct file *filp, fl_owner_t id) { + struct fsnotify_mark_entry *entry; + struct dnotify_mark_entry *dnentry; struct dnotify_struct *dn; struct dnotify_struct **prev; struct inode *inode; @@ -46,145 +203,243 @@ void dnotify_flush(struct file *filp, fl_owner_t id) inode = filp->f_path.dentry->d_inode; if (!S_ISDIR(inode->i_mode)) return; + spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; + entry = fsnotify_find_mark_entry(dnotify_group, inode); + spin_unlock(&inode->i_lock); + if (!entry) + return; + dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + + mutex_lock(&dnotify_mark_mutex); + + spin_lock(&entry->lock); + prev = &dnentry->dn; while ((dn = *prev) != NULL) { if ((dn->dn_owner == id) && (dn->dn_filp == filp)) { *prev = dn->dn_next; - redo_inode_mask(inode); - kmem_cache_free(dn_cache, dn); + kmem_cache_free(dnotify_struct_cache, dn); + dnotify_recalc_inode_mask(entry); break; } prev = &dn->dn_next; } - spin_unlock(&inode->i_lock); + + spin_unlock(&entry->lock); + + /* nothing else could have found us thanks to the dnotify_mark_mutex */ + if (dnentry->dn == NULL) + fsnotify_destroy_mark_by_entry(entry); + + fsnotify_recalc_group_mask(dnotify_group); + + mutex_unlock(&dnotify_mark_mutex); + + fsnotify_put_mark(entry); +} + +/* this conversion is done only at watch creation */ +static __u32 convert_arg(unsigned long arg) +{ + __u32 new_mask = FS_EVENT_ON_CHILD; + + if (arg & DN_MULTISHOT) + new_mask |= FS_DN_MULTISHOT; + if (arg & DN_DELETE) + new_mask |= (FS_DELETE | FS_MOVED_FROM); + if (arg & DN_MODIFY) + new_mask |= FS_MODIFY; + if (arg & DN_ACCESS) + new_mask |= FS_ACCESS; + if (arg & DN_ATTRIB) + new_mask |= FS_ATTRIB; + if (arg & DN_RENAME) + new_mask |= FS_DN_RENAME; + if (arg & DN_CREATE) + new_mask |= (FS_CREATE | FS_MOVED_TO); + + return new_mask; } +/* + * If multiple processes watch the same inode with dnotify there is only one + * dnotify mark in inode->i_fsnotify_mark_entries but we chain a dnotify_struct + * onto that mark. This function either attaches the new dnotify_struct onto + * that list, or it |= the mask onto an existing dnofiy_struct. + */ +static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnentry, + fl_owner_t id, int fd, struct file *filp, __u32 mask) +{ + struct dnotify_struct *odn; + + odn = dnentry->dn; + while (odn != NULL) { + /* adding more events to existing dnofiy_struct? */ + if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { + odn->dn_fd = fd; + odn->dn_mask |= mask; + return -EEXIST; + } + odn = odn->dn_next; + } + + dn->dn_mask = mask; + dn->dn_fd = fd; + dn->dn_filp = filp; + dn->dn_owner = id; + dn->dn_next = dnentry->dn; + dnentry->dn = dn; + + return 0; +} + +/* + * When a process calls fcntl to attach a dnotify watch to a directory it ends + * up here. Allocate both a mark for fsnotify to add and a dnotify_struct to be + * attached to the fsnotify_mark. + */ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) { + struct dnotify_mark_entry *new_dnentry, *dnentry; + struct fsnotify_mark_entry *new_entry, *entry; struct dnotify_struct *dn; - struct dnotify_struct *odn; - struct dnotify_struct **prev; struct inode *inode; fl_owner_t id = current->files; struct file *f; - int error = 0; + int destroy = 0, error = 0; + __u32 mask; + + /* we use these to tell if we need to kfree */ + new_entry = NULL; + dn = NULL; + if (!dir_notify_enable) { + error = -EINVAL; + goto out_err; + } + + /* a 0 mask means we are explicitly removing the watch */ if ((arg & ~DN_MULTISHOT) == 0) { dnotify_flush(filp, id); - return 0; + error = 0; + goto out_err; } - if (!dir_notify_enable) - return -EINVAL; + + /* dnotify only works on directories */ inode = filp->f_path.dentry->d_inode; - if (!S_ISDIR(inode->i_mode)) - return -ENOTDIR; - dn = kmem_cache_alloc(dn_cache, GFP_KERNEL); - if (dn == NULL) - return -ENOMEM; - spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; - while ((odn = *prev) != NULL) { - if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { - odn->dn_fd = fd; - odn->dn_mask |= arg; - inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; - goto out_free; - } - prev = &odn->dn_next; + if (!S_ISDIR(inode->i_mode)) { + error = -ENOTDIR; + goto out_err; } - rcu_read_lock(); - f = fcheck(fd); - rcu_read_unlock(); - /* we'd lost the race with close(), sod off silently */ - /* note that inode->i_lock prevents reordering problems - * between accesses to descriptor table and ->i_dnotify */ - if (f != filp) - goto out_free; + /* expect most fcntl to add new rather than augment old */ + dn = kmem_cache_alloc(dnotify_struct_cache, GFP_KERNEL); + if (!dn) { + error = -ENOMEM; + goto out_err; + } - error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); - if (error) - goto out_free; + /* new fsnotify mark, we expect most fcntl calls to add a new mark */ + new_dnentry = kmem_cache_alloc(dnotify_mark_entry_cache, GFP_KERNEL); + if (!new_dnentry) { + error = -ENOMEM; + goto out_err; + } - dn->dn_mask = arg; - dn->dn_fd = fd; - dn->dn_filp = filp; - dn->dn_owner = id; - inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; - dn->dn_next = inode->i_dnotify; - inode->i_dnotify = dn; - spin_unlock(&inode->i_lock); - return 0; + /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */ + mask = convert_arg(arg); -out_free: - spin_unlock(&inode->i_lock); - kmem_cache_free(dn_cache, dn); - return error; -} + /* set up the new_entry and new_dnentry */ + new_entry = &new_dnentry->fsn_entry; + fsnotify_init_mark(new_entry, dnotify_free_mark); + new_entry->mask = mask; + new_dnentry->dn = NULL; -void __inode_dir_notify(struct inode *inode, unsigned long event) -{ - struct dnotify_struct * dn; - struct dnotify_struct **prev; - struct fown_struct * fown; - int changed = 0; + /* this is needed to prevent the fcntl/close race described below */ + mutex_lock(&dnotify_mark_mutex); + /* add the new_entry or find an old one. */ spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; - while ((dn = *prev) != NULL) { - if ((dn->dn_mask & event) == 0) { - prev = &dn->dn_next; - continue; - } - fown = &dn->dn_filp->f_owner; - send_sigio(fown, dn->dn_fd, POLL_MSG); - if (dn->dn_mask & DN_MULTISHOT) - prev = &dn->dn_next; - else { - *prev = dn->dn_next; - changed = 1; - kmem_cache_free(dn_cache, dn); - } - } - if (changed) - redo_inode_mask(inode); + entry = fsnotify_find_mark_entry(dnotify_group, inode); spin_unlock(&inode->i_lock); -} - -EXPORT_SYMBOL(__inode_dir_notify); + if (entry) { + dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + spin_lock(&entry->lock); + } else { + fsnotify_add_mark(new_entry, dnotify_group, inode); + spin_lock(&new_entry->lock); + entry = new_entry; + dnentry = new_dnentry; + /* we used new_entry, so don't free it */ + new_entry = NULL; + } -/* - * This is hopelessly wrong, but unfixable without API changes. At - * least it doesn't oops the kernel... - * - * To safely access ->d_parent we need to keep d_move away from it. Use the - * dentry's d_lock for this. - */ -void dnotify_parent(struct dentry *dentry, unsigned long event) -{ - struct dentry *parent; + rcu_read_lock(); + f = fcheck(fd); + rcu_read_unlock(); - if (!dir_notify_enable) - return; + /* if (f != filp) means that we lost a race and another task/thread + * actually closed the fd we are still playing with before we grabbed + * the dnotify_mark_mutex and entry->lock. Since closing the fd is the + * only time we clean up the mark entries we need to get our mark off + * the list. */ + if (f != filp) { + /* if we added ourselves, shoot ourselves, it's possible that + * the flush actually did shoot this entry. That's fine too + * since multiple calls to destroy_mark is perfectly safe, if + * we found a dnentry already attached to the inode, just sod + * off silently as the flush at close time dealt with it. + */ + if (dnentry == new_dnentry) + destroy = 1; + goto out; + } - spin_lock(&dentry->d_lock); - parent = dentry->d_parent; - if (parent->d_inode->i_dnotify_mask & event) { - dget(parent); - spin_unlock(&dentry->d_lock); - __inode_dir_notify(parent->d_inode, event); - dput(parent); - } else { - spin_unlock(&dentry->d_lock); + error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); + if (error) { + /* if we added, we must shoot */ + if (dnentry == new_dnentry) + destroy = 1; + goto out; } + + error = attach_dn(dn, dnentry, id, fd, filp, mask); + /* !error means that we attached the dn to the dnentry, so don't free it */ + if (!error) + dn = NULL; + /* -EEXIST means that we didn't add this new dn and used an old one. + * that isn't an error (and the unused dn should be freed) */ + else if (error == -EEXIST) + error = 0; + + dnotify_recalc_inode_mask(entry); +out: + spin_unlock(&entry->lock); + + if (destroy) + fsnotify_destroy_mark_by_entry(entry); + + fsnotify_recalc_group_mask(dnotify_group); + + mutex_unlock(&dnotify_mark_mutex); + fsnotify_put_mark(entry); +out_err: + if (new_entry) + fsnotify_put_mark(new_entry); + if (dn) + kmem_cache_free(dnotify_struct_cache, dn); + return error; } -EXPORT_SYMBOL_GPL(dnotify_parent); static int __init dnotify_init(void) { - dn_cache = kmem_cache_create("dnotify_cache", - sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL); + dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC); + dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC); + + dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM, + 0, &dnotify_fsnotify_ops); + if (IS_ERR(dnotify_group)) + panic("unable to allocate fsnotify group for dnotify\n"); return 0; } -- cgit v1.2.2 From a2d8bc6cb4a3024661baf877242f123787d0c054 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:37 -0400 Subject: fsnotify: generic notification queue and waitq inotify needs to do asyc notification in which event information is stored on a queue until the listener is ready to receive it. This patch implements a generic notification queue for inotify (and later fanotify) to store events to be sent at a later time. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/fsnotify.h | 9 ++ fs/notify/group.c | 9 ++ fs/notify/notification.c | 230 +++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 241 insertions(+), 7 deletions(-) (limited to 'fs') diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 83b8ec0a8ec..4dc240824b2 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -13,8 +13,12 @@ extern struct list_head fsnotify_groups; /* all bitwise OR of all event types (FS_*) for all fsnotify_groups */ extern __u32 fsnotify_mask; +/* destroy all events sitting in this groups notification queue */ +extern void fsnotify_flush_notify(struct fsnotify_group *group); + /* final kfree of a group */ extern void fsnotify_final_destroy_group(struct fsnotify_group *group); + /* run the list of all marks associated with inode and flag them to be freed */ extern void fsnotify_clear_marks_by_inode(struct inode *inode); /* @@ -22,4 +26,9 @@ extern void fsnotify_clear_marks_by_inode(struct inode *inode); * about events that happen to its children. */ extern void __fsnotify_update_child_dentry_flags(struct inode *inode); + +/* allocate and destroy and event holder to attach events to notification/access queues */ +extern struct fsnotify_event_holder *fsnotify_alloc_event_holder(void); +extern void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder); + #endif /* __FS_NOTIFY_FSNOTIFY_H_ */ diff --git a/fs/notify/group.c b/fs/notify/group.c index a29d2fa6792..0e1677144bc 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -91,6 +91,9 @@ static void fsnotify_get_group(struct fsnotify_group *group) */ void fsnotify_final_destroy_group(struct fsnotify_group *group) { + /* clear the notification queue of all events */ + fsnotify_flush_notify(group); + if (group->ops->free_group_priv) group->ops->free_group_priv(group); @@ -214,6 +217,12 @@ struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, group->group_num = group_num; group->mask = mask; + mutex_init(&group->notification_mutex); + INIT_LIST_HEAD(&group->notification_list); + init_waitqueue_head(&group->notification_waitq); + group->q_len = 0; + group->max_events = UINT_MAX; + spin_lock_init(&group->mark_lock); atomic_set(&group->num_marks, 0); INIT_LIST_HEAD(&group->mark_entries); diff --git a/fs/notify/notification.c b/fs/notify/notification.c index b8e9a87f8f5..dddecc74e63 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -16,6 +16,21 @@ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ +/* + * Basic idea behind the notification queue: An fsnotify group (like inotify) + * sends the userspace notification about events asyncronously some time after + * the event happened. When inotify gets an event it will need to add that + * event to the group notify queue. Since a single event might need to be on + * multiple group's notification queues we can't add the event directly to each + * queue and instead add a small "event_holder" to each queue. This event_holder + * has a pointer back to the original event. Since the majority of events are + * going to end up on one, and only one, notification queue we embed one + * event_holder into each event. This means we have a single allocation instead + * of always needing two. If the embedded event_holder is already in use by + * another group a new event_holder (from fsnotify_event_holder_cachep) will be + * allocated and used. + */ + #include #include #include @@ -33,6 +48,21 @@ #include "fsnotify.h" static struct kmem_cache *fsnotify_event_cachep; +static struct kmem_cache *fsnotify_event_holder_cachep; +/* + * This is a magic event we send when the q is too full. Since it doesn't + * hold real event information we just keep one system wide and use it any time + * it is needed. It's refcnt is set 1 at kernel init time and will never + * get set to 0 so it will never get 'freed' + */ +static struct fsnotify_event q_overflow_event; + +/* return true if the notify queue is empty, false otherwise */ +bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group) +{ + BUG_ON(!mutex_is_locked(&group->notification_mutex)); + return list_empty(&group->notification_list) ? true : false; +} void fsnotify_get_event(struct fsnotify_event *event) { @@ -52,19 +82,176 @@ void fsnotify_put_event(struct fsnotify_event *event) } } +struct fsnotify_event_holder *fsnotify_alloc_event_holder(void) +{ + return kmem_cache_alloc(fsnotify_event_holder_cachep, GFP_KERNEL); +} + +void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder) +{ + kmem_cache_free(fsnotify_event_holder_cachep, holder); +} + +/* + * check if 2 events contain the same information. + */ +static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) +{ + if ((old->mask == new->mask) && + (old->to_tell == new->to_tell) && + (old->data_type == new->data_type)) { + switch (old->data_type) { + case (FSNOTIFY_EVENT_INODE): + if (old->inode == new->inode) + return true; + break; + case (FSNOTIFY_EVENT_PATH): + if ((old->path.mnt == new->path.mnt) && + (old->path.dentry == new->path.dentry)) + return true; + case (FSNOTIFY_EVENT_NONE): + return true; + }; + } + return false; +} + /* - * Allocate a new event which will be sent to each group's handle_event function - * if the group was interested in this particular event. + * Add an event to the group notification queue. The group can later pull this + * event off the queue to deal with. If the event is successfully added to the + * group's notification queue, a reference is taken on event. */ -struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, - void *data, int data_type) +int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event) +{ + struct fsnotify_event_holder *holder = NULL; + struct list_head *list = &group->notification_list; + struct fsnotify_event_holder *last_holder; + struct fsnotify_event *last_event; + + /* + * There is one fsnotify_event_holder embedded inside each fsnotify_event. + * Check if we expect to be able to use that holder. If not alloc a new + * holder. + * For the overflow event it's possible that something will use the in + * event holder before we get the lock so we may need to jump back and + * alloc a new holder, this can't happen for most events... + */ + if (!list_empty(&event->holder.event_list)) { +alloc_holder: + holder = fsnotify_alloc_event_holder(); + if (!holder) + return -ENOMEM; + } + + mutex_lock(&group->notification_mutex); + + if (group->q_len >= group->max_events) + event = &q_overflow_event; + + spin_lock(&event->lock); + + if (list_empty(&event->holder.event_list)) { + if (unlikely(holder)) + fsnotify_destroy_event_holder(holder); + holder = &event->holder; + } else if (unlikely(!holder)) { + /* between the time we checked above and got the lock the in + * event holder was used, go back and get a new one */ + spin_unlock(&event->lock); + mutex_unlock(&group->notification_mutex); + goto alloc_holder; + } + + if (!list_empty(list)) { + last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list); + last_event = last_holder->event; + if (event_compare(last_event, event)) { + spin_unlock(&event->lock); + mutex_unlock(&group->notification_mutex); + if (holder != &event->holder) + fsnotify_destroy_event_holder(holder); + return 0; + } + } + + group->q_len++; + holder->event = event; + + fsnotify_get_event(event); + list_add_tail(&holder->event_list, list); + spin_unlock(&event->lock); + mutex_unlock(&group->notification_mutex); + + wake_up(&group->notification_waitq); + return 0; +} + +/* + * Remove and return the first event from the notification list. There is a + * reference held on this event since it was on the list. It is the responsibility + * of the caller to drop this reference. + */ +struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group) { struct fsnotify_event *event; + struct fsnotify_event_holder *holder; - event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL); - if (!event) - return NULL; + BUG_ON(!mutex_is_locked(&group->notification_mutex)); + holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list); + + event = holder->event; + + spin_lock(&event->lock); + holder->event = NULL; + list_del_init(&holder->event_list); + spin_unlock(&event->lock); + + /* event == holder means we are referenced through the in event holder */ + if (holder != &event->holder) + fsnotify_destroy_event_holder(holder); + + group->q_len--; + + return event; +} + +/* + * This will not remove the event, that must be done with fsnotify_remove_notify_event() + */ +struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group) +{ + struct fsnotify_event *event; + struct fsnotify_event_holder *holder; + + BUG_ON(!mutex_is_locked(&group->notification_mutex)); + + holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list); + event = holder->event; + + return event; +} + +/* + * Called when a group is being torn down to clean up any outstanding + * event notifications. + */ +void fsnotify_flush_notify(struct fsnotify_group *group) +{ + struct fsnotify_event *event; + + mutex_lock(&group->notification_mutex); + while (!fsnotify_notify_queue_is_empty(group)) { + event = fsnotify_remove_notify_event(group); + fsnotify_put_event(event); /* matches fsnotify_add_notify_event */ + } + mutex_unlock(&group->notification_mutex); +} + +static void initialize_event(struct fsnotify_event *event) +{ + event->holder.event = NULL; + INIT_LIST_HEAD(&event->holder.event_list); atomic_set(&event->refcnt, 1); spin_lock_init(&event->lock); @@ -72,7 +259,32 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, event->path.dentry = NULL; event->path.mnt = NULL; event->inode = NULL; + event->data_type = FSNOTIFY_EVENT_NONE; + event->to_tell = NULL; +} + +/* + * fsnotify_create_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. + * + * @to_tell the inode which is supposed to receive the event (sometimes a + * parent of the inode to which the event happened. + * @mask what actually happened. + * @data pointer to the object which was actually affected + * @data_type flag indication if the data is a file, path, inode, nothing... + */ +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; + + initialize_event(event); event->to_tell = to_tell; switch (data_type) { @@ -114,6 +326,10 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, __init int fsnotify_notification_init(void) { fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC); + fsnotify_event_holder_cachep = KMEM_CACHE(fsnotify_event_holder, SLAB_PANIC); + + initialize_event(&q_overflow_event); + q_overflow_event.mask = FS_Q_OVERFLOW; return 0; } -- cgit v1.2.2 From 62ffe5dfba056f7ba81d710fee9f28c58a42fdd6 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:43 -0400 Subject: fsnotify: include pathnames with entries when possible When inotify wants to send events to a directory about a child it includes the name of the original file. This patch collects that filename and makes it available for notification. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/fsnotify.c | 7 ++++--- fs/notify/notification.c | 16 +++++++++++++++- 2 files changed, 19 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 7fc760067a6..675129fa9fd 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -114,7 +114,8 @@ void __fsnotify_parent(struct dentry *dentry, __u32 mask) * specifies these are events which came from a child. */ mask |= FS_EVENT_ON_CHILD; - fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE); + fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, + dentry->d_name.name); dput(parent); } @@ -131,7 +132,7 @@ EXPORT_SYMBOL_GPL(__fsnotify_parent); * 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) +void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name) { struct fsnotify_group *group; struct fsnotify_event *event = NULL; @@ -156,7 +157,7 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is) if (!group->ops->should_send_event(group, to_tell, mask)) continue; if (!event) { - event = fsnotify_create_event(to_tell, mask, data, data_is); + event = fsnotify_create_event(to_tell, mask, data, data_is, file_name); /* shit, we OOM'd and now we can't tell, maybe * someday someone else will want to do something * here */ diff --git a/fs/notify/notification.c b/fs/notify/notification.c index dddecc74e63..c69b18b9aba 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -78,6 +78,7 @@ void fsnotify_put_event(struct fsnotify_event *event) if (event->data_type == FSNOTIFY_EVENT_PATH) path_put(&event->path); + kfree(event->file_name); kmem_cache_free(fsnotify_event_cachep, event); } } @@ -262,6 +263,9 @@ static void initialize_event(struct fsnotify_event *event) event->data_type = FSNOTIFY_EVENT_NONE; event->to_tell = NULL; + + event->file_name = NULL; + event->name_len = 0; } /* @@ -274,9 +278,10 @@ static void initialize_event(struct fsnotify_event *event) * @mask what actually happened. * @data pointer to the object which was actually affected * @data_type flag indication if the data is a file, path, inode, nothing... + * @name the filename, if available */ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, - void *data, int data_type) + void *data, int data_type, const char *name) { struct fsnotify_event *event; @@ -285,6 +290,15 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, return NULL; initialize_event(event); + + if (name) { + event->file_name = kstrdup(name, GFP_KERNEL); + if (!event->file_name) { + kmem_cache_free(fsnotify_event_cachep, event); + return NULL; + } + event->name_len = strlen(event->file_name); + } event->to_tell = to_tell; switch (data_type) { -- cgit v1.2.2 From 47882c6f51e8ef41fbbe2bbb746a1ea3228dd7ca Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:47 -0400 Subject: fsnotify: add correlations between events As part of the standard inotify events it includes a correlation cookie between two dentry move operations. This patch includes the same behaviour in fsnotify events. It is needed so that inotify userspace can be implemented on top of fsnotify. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/fsnotify.c | 6 +++--- fs/notify/notification.c | 20 ++++++++++++++++++-- 2 files changed, 21 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 675129fa9fd..f11d75f0236 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -115,7 +115,7 @@ void __fsnotify_parent(struct dentry *dentry, __u32 mask) mask |= FS_EVENT_ON_CHILD; fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, - dentry->d_name.name); + dentry->d_name.name, 0); dput(parent); } @@ -132,7 +132,7 @@ EXPORT_SYMBOL_GPL(__fsnotify_parent); * 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, const char *file_name) +void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name, u32 cookie) { struct fsnotify_group *group; struct fsnotify_event *event = NULL; @@ -157,7 +157,7 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const if (!group->ops->should_send_event(group, to_tell, mask)) continue; if (!event) { - event = fsnotify_create_event(to_tell, mask, data, data_is, file_name); + event = fsnotify_create_event(to_tell, mask, data, data_is, file_name, cookie); /* shit, we OOM'd and now we can't tell, maybe * someday someone else will want to do something * here */ diff --git a/fs/notify/notification.c b/fs/notify/notification.c index c69b18b9aba..346f6e5c355 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -56,6 +57,17 @@ static struct kmem_cache *fsnotify_event_holder_cachep; * get set to 0 so it will never get 'freed' */ static struct fsnotify_event q_overflow_event; +static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0); + +/** + * fsnotify_get_cookie - return a unique cookie for use in synchronizing events. + * Called from fsnotify_move, which is inlined into filesystem modules. + */ +u32 fsnotify_get_cookie(void) +{ + return atomic_inc_return(&fsnotify_sync_cookie); +} +EXPORT_SYMBOL_GPL(fsnotify_get_cookie); /* return true if the notify queue is empty, false otherwise */ bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group) @@ -266,6 +278,8 @@ static void initialize_event(struct fsnotify_event *event) event->file_name = NULL; event->name_len = 0; + + event->sync_cookie = 0; } /* @@ -280,8 +294,8 @@ static void initialize_event(struct fsnotify_event *event) * @data_type flag indication if the data is a file, path, inode, nothing... * @name the filename, if available */ -struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, - void *data, int data_type, const char *name) +struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data, + int data_type, const char *name, u32 cookie) { struct fsnotify_event *event; @@ -299,6 +313,8 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, } event->name_len = strlen(event->file_name); } + + event->sync_cookie = cookie; event->to_tell = to_tell; switch (data_type) { -- cgit v1.2.2 From e4aff117368cfdd3567ee41844d216d079b55173 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:50 -0400 Subject: fsnotify: allow groups to add private data to events inotify needs per group information attached to events. This patch allows groups to attach private information and implements a callback so that information can be freed when an event is being destroyed. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/dnotify/dnotify.c | 1 + fs/notify/notification.c | 52 +++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 49 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index d9d80f502c6..12f9e6b1ffe 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -183,6 +183,7 @@ static struct fsnotify_ops dnotify_fsnotify_ops = { .should_send_event = dnotify_should_send_event, .free_group_priv = NULL, .freeing_mark = dnotify_freeing_mark, + .free_event_priv = NULL, }; /* diff --git a/fs/notify/notification.c b/fs/notify/notification.c index 346f6e5c355..959b73e756f 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -90,6 +90,8 @@ void fsnotify_put_event(struct fsnotify_event *event) if (event->data_type == FSNOTIFY_EVENT_PATH) path_put(&event->path); + BUG_ON(!list_empty(&event->private_data_list)); + kfree(event->file_name); kmem_cache_free(fsnotify_event_cachep, event); } @@ -106,7 +108,29 @@ void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder) } /* - * check if 2 events contain the same information. + * Find the private data that the group previously attached to this event when + * the group added the event to the notification queue (fsnotify_add_notify_event) + */ +struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group, struct fsnotify_event *event) +{ + struct fsnotify_event_private_data *lpriv; + struct fsnotify_event_private_data *priv = NULL; + + assert_spin_locked(&event->lock); + + list_for_each_entry(lpriv, &event->private_data_list, event_list) { + if (lpriv->group == group) { + priv = lpriv; + list_del(&priv->event_list); + break; + } + } + return priv; +} + +/* + * Check if 2 events contain the same information. We do not compare private data + * but at this moment that isn't a problem for any know fsnotify listeners. */ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) { @@ -134,13 +158,17 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new * event off the queue to deal with. If the event is successfully added to the * group's notification queue, a reference is taken on event. */ -int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event) +int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event, + struct fsnotify_event_private_data *priv) { struct fsnotify_event_holder *holder = NULL; struct list_head *list = &group->notification_list; struct fsnotify_event_holder *last_holder; struct fsnotify_event *last_event; + /* easy to tell if priv was attached to the event */ + INIT_LIST_HEAD(&priv->event_list); + /* * There is one fsnotify_event_holder embedded inside each fsnotify_event. * Check if we expect to be able to use that holder. If not alloc a new @@ -158,8 +186,11 @@ alloc_holder: mutex_lock(&group->notification_mutex); - if (group->q_len >= group->max_events) + if (group->q_len >= group->max_events) { event = &q_overflow_event; + /* sorry, no private data on the overflow event */ + priv = NULL; + } spin_lock(&event->lock); @@ -183,7 +214,7 @@ alloc_holder: mutex_unlock(&group->notification_mutex); if (holder != &event->holder) fsnotify_destroy_event_holder(holder); - return 0; + return -EEXIST; } } @@ -192,6 +223,8 @@ alloc_holder: fsnotify_get_event(event); list_add_tail(&holder->event_list, list); + if (priv) + list_add_tail(&priv->event_list, &event->private_data_list); spin_unlock(&event->lock); mutex_unlock(&group->notification_mutex); @@ -252,10 +285,19 @@ struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group) void fsnotify_flush_notify(struct fsnotify_group *group) { struct fsnotify_event *event; + struct fsnotify_event_private_data *priv; mutex_lock(&group->notification_mutex); while (!fsnotify_notify_queue_is_empty(group)) { event = fsnotify_remove_notify_event(group); + /* if they don't implement free_event_priv they better not have attached any */ + if (group->ops->free_event_priv) { + spin_lock(&event->lock); + priv = fsnotify_remove_priv_from_event(group, event); + spin_unlock(&event->lock); + if (priv) + group->ops->free_event_priv(priv); + } fsnotify_put_event(event); /* matches fsnotify_add_notify_event */ } mutex_unlock(&group->notification_mutex); @@ -274,6 +316,8 @@ static void initialize_event(struct fsnotify_event *event) event->inode = NULL; event->data_type = FSNOTIFY_EVENT_NONE; + INIT_LIST_HEAD(&event->private_data_list); + event->to_tell = NULL; event->file_name = NULL; -- cgit v1.2.2 From 1ef5f13c6c8acd3fd10db9f1743f3b4cf30a4abb Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:54 -0400 Subject: fsnotify: fsnotify marks on inodes pin them in core This patch pins any inodes with an fsnotify mark in core. The idea is that as soon as the mark is removed from the inode->fsnotify_mark_entries list the inode will be iput. In reality is doesn't quite work exactly this way. The igrab will happen when the mark is added to an inode, but the iput will happen when the inode pointer is NULL'd inside the mark. It's possible that 2 racing things will try to remove the mark from different directions. One may try to remove the mark because of an explicit request and one might try to remove it because the inode was deleted. It's possible that the removal because of inode deletion will remove the mark from the inode's list, but the removal by explicit request will actually set entry->inode == NULL; and call the iput. This is safe. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/inode_mark.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'fs') diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index a39534845b2..282150f74cf 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -204,6 +204,8 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) */ + iput(inode); + /* * it's possible that this group tried to destroy itself, but this * this mark was simultaneously being freed by inode. If that's the @@ -306,6 +308,10 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry, struct fsnotify_mark_entry *lentry; int ret = 0; + inode = igrab(inode); + if (unlikely(!inode)) + return -EINVAL; + /* * LOCKING ORDER!!!! * entry->lock @@ -337,6 +343,7 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry, if (lentry) { ret = -EEXIST; + iput(inode); fsnotify_put_mark(lentry); } else { __fsnotify_update_child_dentry_flags(inode); -- cgit v1.2.2 From 164bc6195139047faaf5ada1278332e99494803b Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:01:58 -0400 Subject: fsnotify: handle filesystem unmounts with fsnotify marks When an fs is unmounted with an fsnotify mark entry attached to one of its inodes we need to destroy that mark entry and we also (like inotify) send an unmount event. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/inode.c | 1 + fs/notify/inode_mark.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 73 insertions(+) (limited to 'fs') diff --git a/fs/inode.c b/fs/inode.c index 54c63ce3de2..ca337014ae2 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -407,6 +407,7 @@ int invalidate_inodes(struct super_block *sb) mutex_lock(&iprune_mutex); spin_lock(&inode_lock); inotify_unmount_inodes(&sb->s_inodes); + fsnotify_unmount_inodes(&sb->s_inodes); busy = invalidate_list(&sb->s_inodes, &throw_away); spin_unlock(&inode_lock); diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 282150f74cf..0a499d2c619 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -89,6 +89,7 @@ #include #include #include +#include /* for inode_lock */ #include @@ -351,3 +352,74 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry, return ret; } + +/** + * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes. + * @list: list of inodes being unmounted (sb->s_inodes) + * + * Called with inode_lock held, protecting the unmounting super block's list + * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. + * We temporarily drop inode_lock, however, and CAN block. + */ +void fsnotify_unmount_inodes(struct list_head *list) +{ + struct inode *inode, *next_i, *need_iput = NULL; + + list_for_each_entry_safe(inode, next_i, list, i_sb_list) { + struct inode *need_iput_tmp; + + /* + * We cannot __iget() an inode in state I_CLEAR, I_FREEING, + * I_WILL_FREE, or I_NEW which is fine because by that point + * the inode cannot have any associated watches. + */ + if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) + continue; + + /* + * If i_count is zero, the inode cannot have any watches and + * doing an __iget/iput with MS_ACTIVE clear would actually + * evict all inodes with zero i_count from icache which is + * unnecessarily violent and may in fact be illegal to do. + */ + if (!atomic_read(&inode->i_count)) + continue; + + need_iput_tmp = need_iput; + need_iput = NULL; + + /* In case fsnotify_inode_delete() drops a reference. */ + if (inode != need_iput_tmp) + __iget(inode); + else + need_iput_tmp = NULL; + + /* In case the dropping of a reference would nuke next_i. */ + if ((&next_i->i_sb_list != list) && + atomic_read(&next_i->i_count) && + !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) { + __iget(next_i); + need_iput = next_i; + } + + /* + * We can safely drop inode_lock here because we hold + * references on both inode and next_i. Also no new inodes + * will be added since the umount has begun. Finally, + * iprune_mutex keeps shrink_icache_memory() away. + */ + spin_unlock(&inode_lock); + + if (need_iput_tmp) + iput(need_iput_tmp); + + /* for each watch, send FS_UNMOUNT and then remove it */ + fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); + + fsnotify_inode_delete(inode); + + iput(inode); + + spin_lock(&inode_lock); + } +} -- cgit v1.2.2 From 63c882a05416e18de6fb59f7dd6da48f3bbe8273 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 21 May 2009 17:02:01 -0400 Subject: inotify: reimplement inotify using fsnotify Reimplement inotify_user using fsnotify. This should be feature for feature exactly the same as the original inotify_user. This does not make any changes to the in kernel inotify feature used by audit. Those patches (and the eventual removal of in kernel inotify) will come after the new inotify_user proves to be working correctly. Signed-off-by: Eric Paris Acked-by: Al Viro Cc: Christoph Hellwig --- fs/notify/inotify/Kconfig | 20 +- fs/notify/inotify/Makefile | 2 +- fs/notify/inotify/inotify.h | 21 + fs/notify/inotify/inotify_fsnotify.c | 137 ++++++ fs/notify/inotify/inotify_user.c | 837 +++++++++++++++++------------------ 5 files changed, 570 insertions(+), 447 deletions(-) create mode 100644 fs/notify/inotify/inotify.h create mode 100644 fs/notify/inotify/inotify_fsnotify.c (limited to 'fs') diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig index 44679284102..5356884289a 100644 --- a/fs/notify/inotify/Kconfig +++ b/fs/notify/inotify/Kconfig @@ -1,26 +1,30 @@ config INOTIFY bool "Inotify file change notification support" - default y + default n ---help--- - Say Y here to enable inotify support. Inotify is a file change - notification system and a replacement for dnotify. Inotify fixes - numerous shortcomings in dnotify and introduces several new features - including multiple file events, one-shot support, and unmount - notification. + Say Y here to enable legacy in kernel inotify support. Inotify is a + file change notification system. It is a replacement for dnotify. + This option only provides the legacy inotify in kernel API. There + are no in tree kernel users of this interface since it is deprecated. + You only need this if you are loading an out of tree kernel module + that uses inotify. For more information, see - If unsure, say Y. + If unsure, say N. config INOTIFY_USER bool "Inotify support for userspace" - depends on INOTIFY + depends on FSNOTIFY default y ---help--- Say Y here to enable inotify support for userspace, including the associated system calls. Inotify allows monitoring of both files and directories via a single open fd. Events are read from the file descriptor, which is also select()- and poll()-able. + Inotify fixes numerous shortcomings in dnotify and introduces several + new features including multiple file events, one-shot support, and + unmount notification. For more information, see diff --git a/fs/notify/inotify/Makefile b/fs/notify/inotify/Makefile index e290f3bb9d8..94382817136 100644 --- a/fs/notify/inotify/Makefile +++ b/fs/notify/inotify/Makefile @@ -1,2 +1,2 @@ obj-$(CONFIG_INOTIFY) += inotify.o -obj-$(CONFIG_INOTIFY_USER) += inotify_user.o +obj-$(CONFIG_INOTIFY_USER) += inotify_fsnotify.o inotify_user.o diff --git a/fs/notify/inotify/inotify.h b/fs/notify/inotify/inotify.h new file mode 100644 index 00000000000..ea2605a58b8 --- /dev/null +++ b/fs/notify/inotify/inotify.h @@ -0,0 +1,21 @@ +#include +#include +#include /* struct kmem_cache */ + +extern struct kmem_cache *event_priv_cachep; + +struct inotify_event_private_data { + struct fsnotify_event_private_data fsnotify_event_priv_data; + int wd; +}; + +struct inotify_inode_mark_entry { + /* fsnotify_mark_entry MUST be the first thing */ + struct fsnotify_mark_entry fsn_entry; + int wd; +}; + +extern void inotify_destroy_mark_entry(struct fsnotify_mark_entry *entry, struct fsnotify_group *group); +extern void inotify_free_event_priv(struct fsnotify_event_private_data *event_priv); + +extern const struct fsnotify_ops inotify_fsnotify_ops; diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c new file mode 100644 index 00000000000..160da548683 --- /dev/null +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -0,0 +1,137 @@ +/* + * fs/inotify_user.c - inotify support for userspace + * + * Authors: + * John McCutchan + * Robert Love + * + * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. + * + * Copyright (C) 2009 Eric Paris + * inotify was largely rewriten to make use of the fsnotify infrastructure + * + * 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. + */ + +#include /* struct inode */ +#include +#include +#include /* struct path */ +#include /* kmem_* */ +#include + +#include "inotify.h" + +static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) +{ + struct fsnotify_mark_entry *entry; + struct inotify_inode_mark_entry *ientry; + struct inode *to_tell; + struct inotify_event_private_data *event_priv; + struct fsnotify_event_private_data *fsn_event_priv; + int wd, ret; + + to_tell = event->to_tell; + + spin_lock(&to_tell->i_lock); + entry = fsnotify_find_mark_entry(group, to_tell); + spin_unlock(&to_tell->i_lock); + /* race with watch removal? We already passes should_send */ + if (unlikely(!entry)) + return 0; + ientry = container_of(entry, struct inotify_inode_mark_entry, + fsn_entry); + wd = ientry->wd; + + event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); + if (unlikely(!event_priv)) + return -ENOMEM; + + fsn_event_priv = &event_priv->fsnotify_event_priv_data; + + fsn_event_priv->group = group; + event_priv->wd = wd; + + ret = fsnotify_add_notify_event(group, event, fsn_event_priv); + /* EEXIST is not an error */ + if (ret == -EEXIST) + ret = 0; + + /* did event_priv get attached? */ + if (list_empty(&fsn_event_priv->event_list)) + inotify_free_event_priv(fsn_event_priv); + + /* + * If we hold the entry until after the event is on the queue + * IN_IGNORED won't be able to pass this event in the queue + */ + fsnotify_put_mark(entry); + + return ret; +} + +static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) +{ + inotify_destroy_mark_entry(entry, group); +} + +static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) +{ + struct fsnotify_mark_entry *entry; + bool send; + + spin_lock(&inode->i_lock); + entry = fsnotify_find_mark_entry(group, inode); + spin_unlock(&inode->i_lock); + if (!entry) + return false; + + send = (entry->mask & mask); + + /* find took a reference */ + fsnotify_put_mark(entry); + + return send; +} + +static int idr_callback(int id, void *p, void *data) +{ + BUG(); + return 0; +} + +static void inotify_free_group_priv(struct fsnotify_group *group) +{ + /* ideally the idr is empty and we won't hit the BUG in teh callback */ + idr_for_each(&group->inotify_data.idr, idr_callback, NULL); + idr_remove_all(&group->inotify_data.idr); + idr_destroy(&group->inotify_data.idr); +} + +void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv) +{ + struct inotify_event_private_data *event_priv; + + + event_priv = container_of(fsn_event_priv, struct inotify_event_private_data, + fsnotify_event_priv_data); + + kmem_cache_free(event_priv_cachep, event_priv); +} + +const struct fsnotify_ops inotify_fsnotify_ops = { + .handle_event = inotify_handle_event, + .should_send_event = inotify_should_send_event, + .free_group_priv = inotify_free_group_priv, + .free_event_priv = inotify_free_event_priv, + .freeing_mark = inotify_freeing_mark, +}; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 1634319e240..982a412ac5b 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -8,6 +8,9 @@ * Copyright (C) 2005 John McCutchan * Copyright 2006 Hewlett-Packard Development Company, L.P. * + * Copyright (C) 2009 Eric Paris + * inotify was largely rewriten to make use of the fsnotify infrastructure + * * 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 @@ -19,94 +22,48 @@ * General Public License for more details. */ -#include -#include -#include -#include #include -#include -#include -#include -#include -#include +#include /* struct inode */ +#include +#include +#include /* module_init */ #include +#include /* roundup() */ +#include /* superblock magic number */ +#include /* mntget */ +#include /* LOOKUP_FOLLOW */ +#include /* struct path */ +#include /* struct user */ +#include /* struct kmem_cache */ #include -#include +#include +#include +#include +#include -#include +#include "inotify.h" -static struct kmem_cache *watch_cachep __read_mostly; -static struct kmem_cache *event_cachep __read_mostly; +#include static struct vfsmount *inotify_mnt __read_mostly; +/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */ +static struct inotify_event nul_inotify_event; + /* these are configurable via /proc/sys/fs/inotify/ */ static int inotify_max_user_instances __read_mostly; -static int inotify_max_user_watches __read_mostly; static int inotify_max_queued_events __read_mostly; +int inotify_max_user_watches __read_mostly; -/* - * Lock ordering: - * - * inotify_dev->up_mutex (ensures we don't re-add the same watch) - * inode->inotify_mutex (protects inode's watch list) - * inotify_handle->mutex (protects inotify_handle's watch list) - * inotify_dev->ev_mutex (protects device's event queue) - */ +static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; +struct kmem_cache *event_priv_cachep __read_mostly; +static struct fsnotify_event *inotify_ignored_event; /* - * Lifetimes of the main data structures: - * - * inotify_device: Lifetime is managed by reference count, from - * sys_inotify_init() until release. Additional references can bump the count - * via get_inotify_dev() and drop the count via put_inotify_dev(). - * - * inotify_user_watch: Lifetime is from create_watch() to the receipt of an - * IN_IGNORED event from inotify, or when using IN_ONESHOT, to receipt of the - * first event, or to inotify_destroy(). + * When inotify registers a new group it increments this and uses that + * value as an offset to set the fsnotify group "name" and priority. */ - -/* - * struct inotify_device - represents an inotify instance - * - * This structure is protected by the mutex 'mutex'. - */ -struct inotify_device { - wait_queue_head_t wq; /* wait queue for i/o */ - struct mutex ev_mutex; /* protects event queue */ - struct mutex up_mutex; /* synchronizes watch updates */ - struct list_head events; /* list of queued events */ - struct user_struct *user; /* user who opened this dev */ - struct inotify_handle *ih; /* inotify handle */ - struct fasync_struct *fa; /* async notification */ - atomic_t count; /* reference count */ - unsigned int queue_size; /* size of the queue (bytes) */ - unsigned int event_count; /* number of pending events */ - unsigned int max_events; /* maximum number of events */ -}; - -/* - * struct inotify_kernel_event - An inotify event, originating from a watch and - * queued for user-space. A list of these is attached to each instance of the - * device. In read(), this list is walked and all events that can fit in the - * buffer are returned. - * - * Protected by dev->ev_mutex of the device in which we are queued. - */ -struct inotify_kernel_event { - struct inotify_event event; /* the user-space event */ - struct list_head list; /* entry in inotify_device's list */ - char *name; /* filename, if any */ -}; - -/* - * struct inotify_user_watch - our version of an inotify_watch, we add - * a reference to the associated inotify_device. - */ -struct inotify_user_watch { - struct inotify_device *dev; /* associated device */ - struct inotify_watch wdata; /* inotify watch data */ -}; +static atomic_t inotify_grp_num; #ifdef CONFIG_SYSCTL @@ -149,280 +106,36 @@ ctl_table inotify_table[] = { }; #endif /* CONFIG_SYSCTL */ -static inline void get_inotify_dev(struct inotify_device *dev) -{ - atomic_inc(&dev->count); -} - -static inline void put_inotify_dev(struct inotify_device *dev) -{ - if (atomic_dec_and_test(&dev->count)) { - atomic_dec(&dev->user->inotify_devs); - free_uid(dev->user); - kfree(dev); - } -} - -/* - * free_inotify_user_watch - cleans up the watch and its references - */ -static void free_inotify_user_watch(struct inotify_watch *w) -{ - struct inotify_user_watch *watch; - struct inotify_device *dev; - - watch = container_of(w, struct inotify_user_watch, wdata); - dev = watch->dev; - - atomic_dec(&dev->user->inotify_watches); - put_inotify_dev(dev); - kmem_cache_free(watch_cachep, watch); -} - -/* - * kernel_event - create a new kernel event with the given parameters - * - * This function can sleep. - */ -static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie, - const char *name) -{ - struct inotify_kernel_event *kevent; - - kevent = kmem_cache_alloc(event_cachep, GFP_NOFS); - if (unlikely(!kevent)) - return NULL; - - /* we hand this out to user-space, so zero it just in case */ - memset(&kevent->event, 0, sizeof(struct inotify_event)); - - kevent->event.wd = wd; - kevent->event.mask = mask; - kevent->event.cookie = cookie; - - INIT_LIST_HEAD(&kevent->list); - - if (name) { - size_t len, rem, event_size = sizeof(struct inotify_event); - - /* - * We need to pad the filename so as to properly align an - * array of inotify_event structures. Because the structure is - * small and the common case is a small filename, we just round - * up to the next multiple of the structure's sizeof. This is - * simple and safe for all architectures. - */ - len = strlen(name) + 1; - rem = event_size - len; - if (len > event_size) { - rem = event_size - (len % event_size); - if (len % event_size == 0) - rem = 0; - } - - kevent->name = kmalloc(len + rem, GFP_NOFS); - if (unlikely(!kevent->name)) { - kmem_cache_free(event_cachep, kevent); - return NULL; - } - memcpy(kevent->name, name, len); - if (rem) - memset(kevent->name + len, 0, rem); - kevent->event.len = len + rem; - } else { - kevent->event.len = 0; - kevent->name = NULL; - } - - return kevent; -} - -/* - * inotify_dev_get_event - return the next event in the given dev's queue - * - * Caller must hold dev->ev_mutex. - */ -static inline struct inotify_kernel_event * -inotify_dev_get_event(struct inotify_device *dev) -{ - return list_entry(dev->events.next, struct inotify_kernel_event, list); -} - -/* - * inotify_dev_get_last_event - return the last event in the given dev's queue - * - * Caller must hold dev->ev_mutex. - */ -static inline struct inotify_kernel_event * -inotify_dev_get_last_event(struct inotify_device *dev) +static inline __u32 inotify_arg_to_mask(u32 arg) { - if (list_empty(&dev->events)) - return NULL; - return list_entry(dev->events.prev, struct inotify_kernel_event, list); -} + __u32 mask; -/* - * inotify_dev_queue_event - event handler registered with core inotify, adds - * a new event to the given device - * - * Can sleep (calls kernel_event()). - */ -static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask, - u32 cookie, const char *name, - struct inode *ignored) -{ - struct inotify_user_watch *watch; - struct inotify_device *dev; - struct inotify_kernel_event *kevent, *last; + /* everything should accept their own ignored and cares about children */ + mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD); - watch = container_of(w, struct inotify_user_watch, wdata); - dev = watch->dev; + /* mask off the flags used to open the fd */ + mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT)); - mutex_lock(&dev->ev_mutex); - - /* we can safely put the watch as we don't reference it while - * generating the event - */ - if (mask & IN_IGNORED || w->mask & IN_ONESHOT) - put_inotify_watch(w); /* final put */ - - /* coalescing: drop this event if it is a dupe of the previous */ - last = inotify_dev_get_last_event(dev); - if (last && last->event.mask == mask && last->event.wd == wd && - last->event.cookie == cookie) { - const char *lastname = last->name; - - if (!name && !lastname) - goto out; - if (name && lastname && !strcmp(lastname, name)) - goto out; - } - - /* the queue overflowed and we already sent the Q_OVERFLOW event */ - if (unlikely(dev->event_count > dev->max_events)) - goto out; - - /* if the queue overflows, we need to notify user space */ - if (unlikely(dev->event_count == dev->max_events)) - kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL); - else - kevent = kernel_event(wd, mask, cookie, name); - - if (unlikely(!kevent)) - goto out; - - /* queue the event and wake up anyone waiting */ - dev->event_count++; - dev->queue_size += sizeof(struct inotify_event) + kevent->event.len; - list_add_tail(&kevent->list, &dev->events); - wake_up_interruptible(&dev->wq); - kill_fasync(&dev->fa, SIGIO, POLL_IN); - -out: - mutex_unlock(&dev->ev_mutex); -} - -/* - * remove_kevent - cleans up the given kevent - * - * Caller must hold dev->ev_mutex. - */ -static void remove_kevent(struct inotify_device *dev, - struct inotify_kernel_event *kevent) -{ - list_del(&kevent->list); - - dev->event_count--; - dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len; -} - -/* - * free_kevent - frees the given kevent. - */ -static void free_kevent(struct inotify_kernel_event *kevent) -{ - kfree(kevent->name); - kmem_cache_free(event_cachep, kevent); -} - -/* - * inotify_dev_event_dequeue - destroy an event on the given device - * - * Caller must hold dev->ev_mutex. - */ -static void inotify_dev_event_dequeue(struct inotify_device *dev) -{ - if (!list_empty(&dev->events)) { - struct inotify_kernel_event *kevent; - kevent = inotify_dev_get_event(dev); - remove_kevent(dev, kevent); - free_kevent(kevent); - } -} - -/* - * find_inode - resolve a user-given path to a specific inode - */ -static int find_inode(const char __user *dirname, struct path *path, - unsigned flags) -{ - int error; - - error = user_path_at(AT_FDCWD, dirname, flags, path); - if (error) - return error; - /* you can only watch an inode if you have read permissions on it */ - error = inode_permission(path->dentry->d_inode, MAY_READ); - if (error) - path_put(path); - return error; + return mask; } -/* - * create_watch - creates a watch on the given device. - * - * Callers must hold dev->up_mutex. - */ -static int create_watch(struct inotify_device *dev, struct inode *inode, - u32 mask) +static inline u32 inotify_mask_to_arg(__u32 mask) { - struct inotify_user_watch *watch; - int ret; - - if (atomic_read(&dev->user->inotify_watches) >= - inotify_max_user_watches) - return -ENOSPC; - - watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL); - if (unlikely(!watch)) - return -ENOMEM; - - /* save a reference to device and bump the count to make it official */ - get_inotify_dev(dev); - watch->dev = dev; - - atomic_inc(&dev->user->inotify_watches); - - inotify_init_watch(&watch->wdata); - ret = inotify_add_watch(dev->ih, &watch->wdata, inode, mask); - if (ret < 0) - free_inotify_user_watch(&watch->wdata); - - return ret; + return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED | + IN_Q_OVERFLOW); } -/* Device Interface */ - +/* intofiy userspace file descriptor functions */ static unsigned int inotify_poll(struct file *file, poll_table *wait) { - struct inotify_device *dev = file->private_data; + struct fsnotify_group *group = file->private_data; int ret = 0; - poll_wait(file, &dev->wq, wait); - mutex_lock(&dev->ev_mutex); - if (!list_empty(&dev->events)) + poll_wait(file, &group->notification_waitq, wait); + mutex_lock(&group->notification_mutex); + if (!fsnotify_notify_queue_is_empty(group)) ret = POLLIN | POLLRDNORM; - mutex_unlock(&dev->ev_mutex); + mutex_unlock(&group->notification_mutex); return ret; } @@ -432,26 +145,29 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait) * enough to fit in "count". Return an error pointer if * not large enough. * - * Called with the device ev_mutex held. + * Called with the group->notification_mutex held. */ -static struct inotify_kernel_event *get_one_event(struct inotify_device *dev, - size_t count) +static struct fsnotify_event *get_one_event(struct fsnotify_group *group, + size_t count) { size_t event_size = sizeof(struct inotify_event); - struct inotify_kernel_event *kevent; + struct fsnotify_event *event; - if (list_empty(&dev->events)) + if (fsnotify_notify_queue_is_empty(group)) return NULL; - kevent = inotify_dev_get_event(dev); - if (kevent->name) - event_size += kevent->event.len; + event = fsnotify_peek_notify_event(group); + + event_size += roundup(event->name_len, event_size); if (event_size > count) return ERR_PTR(-EINVAL); - remove_kevent(dev, kevent); - return kevent; + /* held the notification_mutex the whole time, so this is the + * same event we peeked above */ + fsnotify_remove_notify_event(group); + + return event; } /* @@ -460,51 +176,90 @@ static struct inotify_kernel_event *get_one_event(struct inotify_device *dev, * We already checked that the event size is smaller than the * buffer we had in "get_one_event()" above. */ -static ssize_t copy_event_to_user(struct inotify_kernel_event *kevent, +static ssize_t copy_event_to_user(struct fsnotify_group *group, + struct fsnotify_event *event, char __user *buf) { + struct inotify_event inotify_event; + struct fsnotify_event_private_data *fsn_priv; + struct inotify_event_private_data *priv; size_t event_size = sizeof(struct inotify_event); + size_t name_len; + + /* we get the inotify watch descriptor from the event private data */ + spin_lock(&event->lock); + fsn_priv = fsnotify_remove_priv_from_event(group, event); + spin_unlock(&event->lock); + + if (!fsn_priv) + inotify_event.wd = -1; + else { + priv = container_of(fsn_priv, struct inotify_event_private_data, + fsnotify_event_priv_data); + inotify_event.wd = priv->wd; + inotify_free_event_priv(fsn_priv); + } + + /* round up event->name_len so it is a multiple of event_size */ + name_len = roundup(event->name_len, event_size); + inotify_event.len = name_len; + + inotify_event.mask = inotify_mask_to_arg(event->mask); + inotify_event.cookie = event->sync_cookie; - if (copy_to_user(buf, &kevent->event, event_size)) + /* send the main event */ + if (copy_to_user(buf, &inotify_event, event_size)) return -EFAULT; - if (kevent->name) { - buf += event_size; + buf += event_size; - if (copy_to_user(buf, kevent->name, kevent->event.len)) + /* + * fsnotify only stores the pathname, so here we have to send the pathname + * and then pad that pathname out to a multiple of sizeof(inotify_event) + * with zeros. I get my zeros from the nul_inotify_event. + */ + if (name_len) { + unsigned int len_to_zero = name_len - event->name_len; + /* copy the path name */ + if (copy_to_user(buf, event->file_name, event->name_len)) return -EFAULT; + buf += event->name_len; - event_size += kevent->event.len; + /* fill userspace with 0's from nul_inotify_event */ + if (copy_to_user(buf, &nul_inotify_event, len_to_zero)) + return -EFAULT; + buf += len_to_zero; + event_size += name_len; } + return event_size; } static ssize_t inotify_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { - struct inotify_device *dev; + struct fsnotify_group *group; + struct fsnotify_event *kevent; char __user *start; int ret; DEFINE_WAIT(wait); start = buf; - dev = file->private_data; + group = file->private_data; while (1) { - struct inotify_kernel_event *kevent; + prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); - prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); - - mutex_lock(&dev->ev_mutex); - kevent = get_one_event(dev, count); - mutex_unlock(&dev->ev_mutex); + mutex_lock(&group->notification_mutex); + kevent = get_one_event(group, count); + mutex_unlock(&group->notification_mutex); if (kevent) { ret = PTR_ERR(kevent); if (IS_ERR(kevent)) break; - ret = copy_event_to_user(kevent, buf); - free_kevent(kevent); + ret = copy_event_to_user(group, kevent, buf); + fsnotify_put_event(kevent); if (ret < 0) break; buf += ret; @@ -525,7 +280,7 @@ static ssize_t inotify_read(struct file *file, char __user *buf, schedule(); } - finish_wait(&dev->wq, &wait); + finish_wait(&group->notification_waitq, &wait); if (start != buf && ret != -EFAULT) ret = buf - start; return ret; @@ -533,25 +288,19 @@ static ssize_t inotify_read(struct file *file, char __user *buf, static int inotify_fasync(int fd, struct file *file, int on) { - struct inotify_device *dev = file->private_data; + struct fsnotify_group *group = file->private_data; - return fasync_helper(fd, file, on, &dev->fa) >= 0 ? 0 : -EIO; + return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO; } static int inotify_release(struct inode *ignored, struct file *file) { - struct inotify_device *dev = file->private_data; - - inotify_destroy(dev->ih); + struct fsnotify_group *group = file->private_data; - /* destroy all of the events on this device */ - mutex_lock(&dev->ev_mutex); - while (!list_empty(&dev->events)) - inotify_dev_event_dequeue(dev); - mutex_unlock(&dev->ev_mutex); + fsnotify_clear_marks_by_group(group); - /* free this device: the put matching the get in inotify_init() */ - put_inotify_dev(dev); + /* free this group, matching get was inotify_init->fsnotify_obtain_group */ + fsnotify_put_group(group); return 0; } @@ -559,16 +308,27 @@ static int inotify_release(struct inode *ignored, struct file *file) static long inotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct inotify_device *dev; + struct fsnotify_group *group; + struct fsnotify_event_holder *holder; + struct fsnotify_event *event; void __user *p; int ret = -ENOTTY; + size_t send_len = 0; - dev = file->private_data; + group = file->private_data; p = (void __user *) arg; switch (cmd) { case FIONREAD: - ret = put_user(dev->queue_size, (int __user *) p); + mutex_lock(&group->notification_mutex); + list_for_each_entry(holder, &group->notification_list, event_list) { + event = holder->event; + send_len += sizeof(struct inotify_event); + send_len += roundup(event->name_len, + sizeof(struct inotify_event)); + } + mutex_unlock(&group->notification_mutex); + ret = put_user(send_len, (int __user *) p); break; } @@ -576,23 +336,233 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, } static const struct file_operations inotify_fops = { - .poll = inotify_poll, - .read = inotify_read, - .fasync = inotify_fasync, - .release = inotify_release, - .unlocked_ioctl = inotify_ioctl, + .poll = inotify_poll, + .read = inotify_read, + .fasync = inotify_fasync, + .release = inotify_release, + .unlocked_ioctl = inotify_ioctl, .compat_ioctl = inotify_ioctl, }; -static const struct inotify_operations inotify_user_ops = { - .handle_event = inotify_dev_queue_event, - .destroy_watch = free_inotify_user_watch, -}; +/* + * find_inode - resolve a user-given path to a specific inode + */ +static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags) +{ + int error; + + error = user_path_at(AT_FDCWD, dirname, flags, path); + if (error) + return error; + /* you can only watch an inode if you have read permissions on it */ + error = inode_permission(path->dentry->d_inode, MAY_READ); + if (error) + path_put(path); + return error; +} + +/* + * When, for whatever reason, inotify is done with a mark (or what used to be a + * watch) we need to remove that watch from the idr and we need to send IN_IGNORED + * for the given wd. + * + * There is a bit of recursion here. The loop looks like: + * inotify_destroy_mark_entry -> fsnotify_destroy_mark_by_entry -> + * inotify_freeing_mark -> inotify_destory_mark_entry -> restart + * But the loop is broken in 2 places. fsnotify_destroy_mark_by_entry sets + * entry->group = NULL before the call to inotify_freeing_mark, so the if (egroup) + * test below will not call back to fsnotify again. But even if that test wasn't + * there this would still be safe since fsnotify_destroy_mark_by_entry() is + * safe from recursion. + */ +void inotify_destroy_mark_entry(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) +{ + struct inotify_inode_mark_entry *ientry; + struct inotify_event_private_data *event_priv; + struct fsnotify_event_private_data *fsn_event_priv; + struct fsnotify_group *egroup; + struct idr *idr; + + spin_lock(&entry->lock); + egroup = entry->group; + + /* if egroup we aren't really done and something might still send events + * for this inode, on the callback we'll send the IN_IGNORED */ + if (egroup) { + spin_unlock(&entry->lock); + fsnotify_destroy_mark_by_entry(entry); + return; + } + spin_unlock(&entry->lock); + + ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + + event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); + if (unlikely(!event_priv)) + goto skip_send_ignore; + + fsn_event_priv = &event_priv->fsnotify_event_priv_data; + + fsn_event_priv->group = group; + event_priv->wd = ientry->wd; + + fsnotify_add_notify_event(group, inotify_ignored_event, fsn_event_priv); + + /* did the private data get added? */ + if (list_empty(&fsn_event_priv->event_list)) + inotify_free_event_priv(fsn_event_priv); + +skip_send_ignore: + + /* remove this entry from the idr */ + spin_lock(&group->inotify_data.idr_lock); + idr = &group->inotify_data.idr; + idr_remove(idr, ientry->wd); + spin_unlock(&group->inotify_data.idr_lock); + + /* removed from idr, drop that reference */ + fsnotify_put_mark(entry); +} + +/* ding dong the mark is dead */ +static void inotify_free_mark(struct fsnotify_mark_entry *entry) +{ + struct inotify_inode_mark_entry *ientry = (struct inotify_inode_mark_entry *)entry; + + kmem_cache_free(inotify_inode_mark_cachep, ientry); +} + +static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) +{ + struct fsnotify_mark_entry *entry = NULL; + struct inotify_inode_mark_entry *ientry; + int ret = 0; + int add = (arg & IN_MASK_ADD); + __u32 mask; + __u32 old_mask, new_mask; + + /* don't allow invalid bits: we don't want flags set */ + mask = inotify_arg_to_mask(arg); + if (unlikely(!mask)) + return -EINVAL; + + ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); + if (unlikely(!ientry)) + return -ENOMEM; + /* we set the mask at the end after attaching it */ + fsnotify_init_mark(&ientry->fsn_entry, inotify_free_mark); + ientry->wd = 0; + +find_entry: + spin_lock(&inode->i_lock); + entry = fsnotify_find_mark_entry(group, inode); + spin_unlock(&inode->i_lock); + if (entry) { + kmem_cache_free(inotify_inode_mark_cachep, ientry); + ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + } else { + if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) { + ret = -ENOSPC; + goto out_err; + } + + ret = fsnotify_add_mark(&ientry->fsn_entry, group, inode); + if (ret == -EEXIST) + goto find_entry; + else if (ret) + goto out_err; + + entry = &ientry->fsn_entry; +retry: + ret = -ENOMEM; + if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) + goto out_err; + + spin_lock(&group->inotify_data.idr_lock); + /* if entry is added to the idr we keep the reference obtained + * through fsnotify_mark_add. remember to drop this reference + * when entry is removed from idr */ + ret = idr_get_new_above(&group->inotify_data.idr, entry, + ++group->inotify_data.last_wd, + &ientry->wd); + spin_unlock(&group->inotify_data.idr_lock); + if (ret) { + if (ret == -EAGAIN) + goto retry; + goto out_err; + } + atomic_inc(&group->inotify_data.user->inotify_watches); + } + + spin_lock(&entry->lock); + + old_mask = entry->mask; + if (add) { + entry->mask |= mask; + new_mask = entry->mask; + } else { + entry->mask = mask; + new_mask = entry->mask; + } + + spin_unlock(&entry->lock); + + if (old_mask != new_mask) { + /* more bits in old than in new? */ + int dropped = (old_mask & ~new_mask); + /* more bits in this entry than the inode's mask? */ + int do_inode = (new_mask & ~inode->i_fsnotify_mask); + /* more bits in this entry than the group? */ + int do_group = (new_mask & ~group->mask); + + /* update the inode with this new entry */ + if (dropped || do_inode) + fsnotify_recalc_inode_mask(inode); + + /* update the group mask with the new mask */ + if (dropped || do_group) + fsnotify_recalc_group_mask(group); + } + + return ientry->wd; + +out_err: + /* see this isn't supposed to happen, just kill the watch */ + if (entry) { + fsnotify_destroy_mark_by_entry(entry); + fsnotify_put_mark(entry); + } + return ret; +} + +static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events) +{ + struct fsnotify_group *group; + unsigned int grp_num; + + /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ + grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num)); + group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops); + if (IS_ERR(group)) + return group; + + group->max_events = max_events; + + spin_lock_init(&group->inotify_data.idr_lock); + idr_init(&group->inotify_data.idr); + group->inotify_data.last_wd = 0; + group->inotify_data.user = user; + group->inotify_data.fa = NULL; + + return group; +} + + +/* inotify syscalls */ SYSCALL_DEFINE1(inotify_init1, int, flags) { - struct inotify_device *dev; - struct inotify_handle *ih; + struct fsnotify_group *group; struct user_struct *user; struct file *filp; int fd, ret; @@ -621,45 +591,27 @@ SYSCALL_DEFINE1(inotify_init1, int, flags) goto out_free_uid; } - dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); - if (unlikely(!dev)) { - ret = -ENOMEM; + /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ + group = inotify_new_group(user, inotify_max_queued_events); + if (IS_ERR(group)) { + ret = PTR_ERR(group); goto out_free_uid; } - ih = inotify_init(&inotify_user_ops); - if (IS_ERR(ih)) { - ret = PTR_ERR(ih); - goto out_free_dev; - } - dev->ih = ih; - dev->fa = NULL; - filp->f_op = &inotify_fops; filp->f_path.mnt = mntget(inotify_mnt); filp->f_path.dentry = dget(inotify_mnt->mnt_root); filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping; filp->f_mode = FMODE_READ; filp->f_flags = O_RDONLY | (flags & O_NONBLOCK); - filp->private_data = dev; - - INIT_LIST_HEAD(&dev->events); - init_waitqueue_head(&dev->wq); - mutex_init(&dev->ev_mutex); - mutex_init(&dev->up_mutex); - dev->event_count = 0; - dev->queue_size = 0; - dev->max_events = inotify_max_queued_events; - dev->user = user; - atomic_set(&dev->count, 0); - - get_inotify_dev(dev); + filp->private_data = group; + atomic_inc(&user->inotify_devs); + fd_install(fd, filp); return fd; -out_free_dev: - kfree(dev); + out_free_uid: free_uid(user); put_filp(filp); @@ -676,8 +628,8 @@ SYSCALL_DEFINE0(inotify_init) SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, u32, mask) { + struct fsnotify_group *group; struct inode *inode; - struct inotify_device *dev; struct path path; struct file *filp; int ret, fput_needed; @@ -698,20 +650,20 @@ SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname, if (mask & IN_ONLYDIR) flags |= LOOKUP_DIRECTORY; - ret = find_inode(pathname, &path, flags); - if (unlikely(ret)) + ret = inotify_find_inode(pathname, &path, flags); + if (ret) goto fput_and_out; - /* inode held in place by reference to path; dev by fget on fd */ + /* inode held in place by reference to path; group by fget on fd */ inode = path.dentry->d_inode; - dev = filp->private_data; + group = filp->private_data; - mutex_lock(&dev->up_mutex); - ret = inotify_find_update_watch(dev->ih, inode, mask); - if (ret == -ENOENT) - ret = create_watch(dev, inode, mask); - mutex_unlock(&dev->up_mutex); + /* create/update an inode mark */ + ret = inotify_update_watch(group, inode, mask); + if (unlikely(ret)) + goto path_put_and_out; +path_put_and_out: path_put(&path); fput_and_out: fput_light(filp, fput_needed); @@ -720,9 +672,10 @@ fput_and_out: SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) { + struct fsnotify_group *group; + struct fsnotify_mark_entry *entry; struct file *filp; - struct inotify_device *dev; - int ret, fput_needed; + int ret = 0, fput_needed; filp = fget_light(fd, &fput_needed); if (unlikely(!filp)) @@ -734,10 +687,20 @@ SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) goto out; } - dev = filp->private_data; + group = filp->private_data; - /* we free our watch data when we get IN_IGNORED */ - ret = inotify_rm_wd(dev->ih, wd); + spin_lock(&group->inotify_data.idr_lock); + entry = idr_find(&group->inotify_data.idr, wd); + if (unlikely(!entry)) { + spin_unlock(&group->inotify_data.idr_lock); + ret = -EINVAL; + goto out; + } + fsnotify_get_mark(entry); + spin_unlock(&group->inotify_data.idr_lock); + + inotify_destroy_mark_entry(entry, group); + fsnotify_put_mark(entry); out: fput_light(filp, fput_needed); @@ -753,9 +716,9 @@ inotify_get_sb(struct file_system_type *fs_type, int flags, } static struct file_system_type inotify_fs_type = { - .name = "inotifyfs", - .get_sb = inotify_get_sb, - .kill_sb = kill_anon_super, + .name = "inotifyfs", + .get_sb = inotify_get_sb, + .kill_sb = kill_anon_super, }; /* @@ -775,18 +738,16 @@ static int __init inotify_user_setup(void) if (IS_ERR(inotify_mnt)) panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); + inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC); + event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); + inotify_ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, FSNOTIFY_EVENT_NONE, NULL, 0); + if (!inotify_ignored_event) + panic("unable to allocate the inotify ignored event\n"); + inotify_max_queued_events = 16384; inotify_max_user_instances = 128; inotify_max_user_watches = 8192; - watch_cachep = kmem_cache_create("inotify_watch_cache", - sizeof(struct inotify_user_watch), - 0, SLAB_PANIC, NULL); - event_cachep = kmem_cache_create("inotify_event_cache", - sizeof(struct inotify_kernel_event), - 0, SLAB_PANIC, NULL); - return 0; } - module_init(inotify_user_setup); -- cgit v1.2.2 From 5ac697b793a3c45005c568df692518da6e690390 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 11 Jun 2009 11:09:47 -0400 Subject: dnotify: do not use ?true:false when assigning to a bool dnotify_should send event assigned a bool using ?true:false when computing a bit operation. This is poitless and the bool type does this for us. Signed-off-by: Eric Paris --- fs/notify/dnotify/dnotify.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 12f9e6b1ffe..5134e898f60 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -154,7 +154,7 @@ static bool dnotify_should_send_event(struct fsnotify_group *group, return false; spin_lock(&entry->lock); - send = (mask & entry->mask) ? true : false; + send = (mask & entry->mask); spin_unlock(&entry->lock); fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ -- cgit v1.2.2 From ce61856bd2aadb064f595e5c0444376a2b117c41 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 11 Jun 2009 11:09:47 -0400 Subject: dnotify: do not bother to lock entry->lock when reading mask entry->lock is needed to make sure entry->mask does not change while manipulating it. In dnotify_should_send_event() we don't care if we get an old or a new mask value out of this entry so there is no point it taking the lock. Signed-off-by: Eric Paris --- fs/notify/dnotify/dnotify.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 5134e898f60..ec459b6e8c6 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -153,9 +153,8 @@ static bool dnotify_should_send_event(struct fsnotify_group *group, if (!entry) return false; - spin_lock(&entry->lock); send = (mask & entry->mask); - spin_unlock(&entry->lock); + fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ return send; -- cgit v1.2.2 From e42e27736de80045f925564ea27a1d32957219e7 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 11 Jun 2009 11:09:47 -0400 Subject: inotify/dnotify: should_send_event shouldn't match on FS_EVENT_ON_CHILD inotify and dnotify will both indicate that they want any event which came from a child inode. The fix is to mask off FS_EVENT_ON_CHILD when deciding if inotify or dnotify is interested in a given event. Signed-off-by: Eric Paris --- fs/notify/dnotify/dnotify.c | 1 + fs/notify/fsnotify.c | 8 +++++--- fs/notify/inotify/inotify_fsnotify.c | 1 + 3 files changed, 7 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index ec459b6e8c6..98a751614c7 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -153,6 +153,7 @@ static bool dnotify_should_send_event(struct fsnotify_group *group, if (!entry) return false; + mask = (mask & ~FS_EVENT_ON_CHILD); send = (mask & entry->mask); fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index f11d75f0236..ec2f7bd7681 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -137,14 +137,16 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const struct fsnotify_group *group; struct fsnotify_event *event = NULL; int idx; + /* global tests shouldn't care about events on child only the specific event */ + __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); if (list_empty(&fsnotify_groups)) return; - if (!(mask & fsnotify_mask)) + if (!(test_mask & fsnotify_mask)) return; - if (!(mask & to_tell->i_fsnotify_mask)) + if (!(test_mask & to_tell->i_fsnotify_mask)) return; /* * SRCU!! the groups list is very very much read only and the path is @@ -153,7 +155,7 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const */ idx = srcu_read_lock(&fsnotify_grp_srcu); list_for_each_entry_rcu(group, &fsnotify_groups, group_list) { - if (mask & group->mask) { + if (test_mask & group->mask) { if (!group->ops->should_send_event(group, to_tell, mask)) continue; if (!event) { diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 160da548683..7ef75b83247 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -95,6 +95,7 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode if (!entry) return false; + mask = (mask & ~FS_EVENT_ON_CHILD); send = (entry->mask & mask); /* find took a reference */ -- cgit v1.2.2 From a092ee20fd33d2df0990dcbf2235afc181612818 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 11 Jun 2009 11:09:48 -0400 Subject: fsnotify: allow groups to set freeing_mark to null Most fsnotify listeners (all but inotify) do not care about marks being freed. Allow groups to set freeing_mark to null and do not call any function if it is set that way. Signed-off-by: Eric Paris --- fs/notify/dnotify/dnotify.c | 8 +------- fs/notify/inode_mark.c | 3 ++- 2 files changed, 3 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 98a751614c7..828a889be90 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -161,12 +161,6 @@ static bool dnotify_should_send_event(struct fsnotify_group *group, return send; } -static void dnotify_freeing_mark(struct fsnotify_mark_entry *entry, - struct fsnotify_group *group) -{ - /* dnotify doesn't care than an inode is on the way out */ -} - static void dnotify_free_mark(struct fsnotify_mark_entry *entry) { struct dnotify_mark_entry *dnentry = container_of(entry, @@ -182,7 +176,7 @@ static struct fsnotify_ops dnotify_fsnotify_ops = { .handle_event = dnotify_handle_event, .should_send_event = dnotify_should_send_event, .free_group_priv = NULL, - .freeing_mark = dnotify_freeing_mark, + .freeing_mark = NULL, .free_event_priv = NULL, }; diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 0a499d2c619..c8a07c65482 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -190,7 +190,8 @@ void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) * callback to the group function to let it know that this entry * is being freed. */ - group->ops->freeing_mark(entry, group); + if (group->ops->freeing_mark) + group->ops->freeing_mark(entry, group); /* * __fsnotify_update_child_dentry_flags(inode); -- cgit v1.2.2