diff options
| -rw-r--r-- | MAINTAINERS | 2 | ||||
| -rw-r--r-- | fs/notify/inotify/Kconfig | 20 | ||||
| -rw-r--r-- | fs/notify/inotify/Makefile | 2 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.h | 21 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_fsnotify.c | 137 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 837 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 11 | ||||
| -rw-r--r-- | init/Kconfig | 3 |
8 files changed, 585 insertions, 448 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 96e0c8c..e697b67 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2858,6 +2858,8 @@ P: John McCutchan M: john@johnmccutchan.com P: Robert Love M: rlove@rlove.org +P: Eric Paris +M: eparis@parisplace.org L: linux-kernel@vger.kernel.org S: Maintained F: Documentation/filesystems/inotify.txt diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig index 4467928..5356884 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 <file:Documentation/filesystems/inotify.txt> - 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 <file:Documentation/filesystems/inotify.txt> diff --git a/fs/notify/inotify/Makefile b/fs/notify/inotify/Makefile index e290f3b..9438281 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 0000000..ea2605a --- /dev/null +++ b/fs/notify/inotify/inotify.h @@ -0,0 +1,21 @@ +#include <linux/fsnotify_backend.h> +#include <linux/inotify.h> +#include <linux/slab.h> /* 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 0000000..160da54 --- /dev/null +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -0,0 +1,137 @@ +/* + * fs/inotify_user.c - inotify support for userspace + * + * Authors: + * John McCutchan <ttb@tentacle.dhs.org> + * Robert Love <rml@novell.com> + * + * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. + * + * Copyright (C) 2009 Eric Paris <Red Hat Inc> + * 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 <linux/fs.h> /* struct inode */ +#include <linux/fsnotify_backend.h> +#include <linux/inotify.h> +#include <linux/path.h> /* struct path */ +#include <linux/slab.h> /* kmem_* */ +#include <linux/types.h> + +#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 1634319..982a412 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 <Red Hat Inc> + * 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 <linux/kernel.h> -#include <linux/sched.h> -#include <linux/slab.h> -#include <linux/fs.h> #include <linux/file.h> -#include <linux/mount.h> -#include <linux/namei.h> -#include <linux/poll.h> -#include <linux/init.h> -#include <linux/list.h> +#include <linux/fs.h> /* struct inode */ +#include <linux/fsnotify_backend.h> +#include <linux/idr.h> +#include <linux/init.h> /* module_init */ #include <linux/inotify.h> +#include <linux/kernel.h> /* roundup() */ +#include <linux/magic.h> /* superblock magic number */ +#include <linux/mount.h> /* mntget */ +#include <linux/namei.h> /* LOOKUP_FOLLOW */ +#include <linux/path.h> /* struct path */ +#include <linux/sched.h> /* struct user */ +#include <linux/slab.h> /* struct kmem_cache */ #include <linux/syscalls.h> -#include <linux/magic.h> +#include <linux/types.h> +#include <linux/uaccess.h> +#include <linux/poll.h> +#include <linux/wait.h> -#include <asm/ioctls.h> +#include "inotify.h" -static struct kmem_cache *watch_cachep __read_mostly; -static struct kmem_cache *event_cachep __read_mostly; +#include <asm/ioctls.h> 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); diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index d2c0ee3..44848aa 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -9,6 +9,7 @@ #ifdef __KERNEL__ +#include <linux/idr.h> /* inotify uses this */ #include <linux/fs.h> /* struct inode */ #include <linux/list.h> #include <linux/path.h> /* struct path */ @@ -59,6 +60,7 @@ /* listeners that hard code group numbers near the top */ #define DNOTIFY_GROUP_NUM UINT_MAX +#define INOTIFY_GROUP_NUM (DNOTIFY_GROUP_NUM-1) struct fsnotify_group; struct fsnotify_event; @@ -141,6 +143,15 @@ struct fsnotify_group { /* groups can define private fields here or use the void *private */ union { void *private; +#ifdef CONFIG_INOTIFY_USER + struct inotify_group_private_data { + spinlock_t idr_lock; + struct idr idr; + u32 last_wd; + struct fasync_struct *fa; /* async notification */ + struct user_struct *user; + } inotify_data; +#endif }; }; diff --git a/init/Kconfig b/init/Kconfig index d4e9671..5de1c17c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -302,7 +302,8 @@ config AUDITSYSCALL config AUDIT_TREE def_bool y - depends on AUDITSYSCALL && INOTIFY + depends on AUDITSYSCALL + select INOTIFY menu "RCU Subsystem" |
