From 0eeca28300df110bd6ed54b31193c83b87921443 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Tue, 12 Jul 2005 17:06:03 -0400 Subject: [PATCH] inotify inotify is intended to correct the deficiencies of dnotify, particularly its inability to scale and its terrible user interface: * dnotify requires the opening of one fd per each directory that you intend to watch. This quickly results in too many open files and pins removable media, preventing unmount. * dnotify is directory-based. You only learn about changes to directories. Sure, a change to a file in a directory affects the directory, but you are then forced to keep a cache of stat structures. * dnotify's interface to user-space is awful. Signals? inotify provides a more usable, simple, powerful solution to file change notification: * inotify's interface is a system call that returns a fd, not SIGIO. You get a single fd, which is select()-able. * inotify has an event that says "the filesystem that the item you were watching is on was unmounted." * inotify can watch directories or files. Inotify is currently used by Beagle (a desktop search infrastructure), Gamin (a FAM replacement), and other projects. See Documentation/filesystems/inotify.txt. Signed-off-by: Robert Love Cc: John McCutchan Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/inotify.c | 999 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 999 insertions(+) create mode 100644 fs/inotify.c (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c new file mode 100644 index 000000000000..e423bfe0c86f --- /dev/null +++ b/fs/inotify.c @@ -0,0 +1,999 @@ +/* + * fs/inotify.c - inode-based file event notifications + * + * Authors: + * John McCutchan + * Robert Love + * + * Copyright (C) 2005 John McCutchan + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +static atomic_t inotify_cookie; + +static kmem_cache_t *watch_cachep; +static kmem_cache_t *event_cachep; + +static struct vfsmount *inotify_mnt; + +/* These are configurable via /proc/sys/inotify */ +int inotify_max_user_devices; +int inotify_max_user_watches; +int inotify_max_queued_events; + +/* + * Lock ordering: + * + * dentry->d_lock (used to keep d_move() away from dentry->d_parent) + * iprune_sem (synchronize shrink_icache_memory()) + * inode_lock (protects the super_block->s_inodes list) + * inode->inotify_sem (protects inode->inotify_watches and watches->i_list) + * inotify_dev->sem (protects inotify_device and watches->d_list) + */ + +/* + * Lifetimes of the three main data structures--inotify_device, inode, and + * inotify_watch--are managed by reference count. + * + * inotify_device: Lifetime is from open until release. Additional references + * can bump the count via get_inotify_dev() and drop the count via + * put_inotify_dev(). + * + * inotify_watch: Lifetime is from create_watch() to destory_watch(). + * Additional references can bump the count via get_inotify_watch() and drop + * the count via put_inotify_watch(). + * + * inode: Pinned so long as the inode is associated with a watch, from + * create_watch() to put_inotify_watch(). + */ + +/* + * struct inotify_device - represents an open instance of an inotify device + * + * This structure is protected by the semaphore 'sem'. + */ +struct inotify_device { + wait_queue_head_t wq; /* wait queue for i/o */ + struct idr idr; /* idr mapping wd -> watch */ + struct semaphore sem; /* protects this bad boy */ + struct list_head events; /* list of queued events */ + struct list_head watches; /* list of watches */ + atomic_t count; /* reference count */ + struct user_struct *user; /* user who opened this dev */ + 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->sem 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_watch - represents a watch request on a specific inode + * + * d_list is protected by dev->sem of the associated watch->dev. + * i_list and mask are protected by inode->inotify_sem of the associated inode. + * dev, inode, and wd are never written to once the watch is created. + */ +struct inotify_watch { + struct list_head d_list; /* entry in inotify_device's list */ + struct list_head i_list; /* entry in inode's list */ + atomic_t count; /* reference count */ + struct inotify_device *dev; /* associated device */ + struct inode *inode; /* associated inode */ + s32 wd; /* watch descriptor */ + u32 mask; /* event mask for this watch */ +}; + +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); + } +} + +static inline void get_inotify_watch(struct inotify_watch *watch) +{ + atomic_inc(&watch->count); +} + +/* + * put_inotify_watch - decrements the ref count on a given watch. cleans up + * the watch and its references if the count reaches zero. + */ +static inline void put_inotify_watch(struct inotify_watch *watch) +{ + if (atomic_dec_and_test(&watch->count)) { + put_inotify_dev(watch->dev); + iput(watch->inode); + 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_KERNEL); + 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_KERNEL); + 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->sem. + */ +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_queue_event - add a new event to the given device + * + * Caller must hold dev->sem. Can sleep (calls kernel_event()). + */ +static void inotify_dev_queue_event(struct inotify_device *dev, + struct inotify_watch *watch, u32 mask, + u32 cookie, const char *name) +{ + struct inotify_kernel_event *kevent, *last; + + /* coalescing: drop this event if it is a dupe of the previous */ + last = inotify_dev_get_event(dev); + if (last && last->event.mask == mask && last->event.wd == watch->wd && + last->event.cookie == cookie) { + const char *lastname = last->name; + + if (!name && !lastname) + return; + if (name && lastname && !strcmp(lastname, name)) + return; + } + + /* the queue overflowed and we already sent the Q_OVERFLOW event */ + if (unlikely(dev->event_count > dev->max_events)) + return; + + /* 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(watch->wd, mask, cookie, name); + + if (unlikely(!kevent)) + return; + + /* 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); +} + +/* + * remove_kevent - cleans up and ultimately frees the given kevent + * + * Caller must hold dev->sem. + */ +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; + + kfree(kevent->name); + kmem_cache_free(event_cachep, kevent); +} + +/* + * inotify_dev_event_dequeue - destroy an event on the given device + * + * Caller must hold dev->sem. + */ +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); + } +} + +/* + * inotify_dev_get_wd - returns the next WD for use by the given dev + * + * Callers must hold dev->sem. This function can sleep. + */ +static int inotify_dev_get_wd(struct inotify_device *dev, + struct inotify_watch *watch) +{ + int ret; + + do { + if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL))) + return -ENOSPC; + ret = idr_get_new(&dev->idr, watch, &watch->wd); + } while (ret == -EAGAIN); + + return ret; +} + +/* + * find_inode - resolve a user-given path to a specific inode and return a nd + */ +static int find_inode(const char __user *dirname, struct nameidata *nd) +{ + int error; + + error = __user_walk(dirname, LOOKUP_FOLLOW, nd); + if (error) + return error; + /* you can only watch an inode if you have read permissions on it */ + error = permission(nd->dentry->d_inode, MAY_READ, NULL); + if (error) + path_release (nd); + return error; +} + +/* + * create_watch - creates a watch on the given device. + * + * Callers must hold dev->sem. Calls inotify_dev_get_wd() so may sleep. + * Both 'dev' and 'inode' (by way of nameidata) need to be pinned. + */ +static struct inotify_watch *create_watch(struct inotify_device *dev, + u32 mask, struct inode *inode) +{ + struct inotify_watch *watch; + int ret; + + if (atomic_read(&dev->user->inotify_watches) >= inotify_max_user_watches) + return ERR_PTR(-ENOSPC); + + watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL); + if (unlikely(!watch)) + return ERR_PTR(-ENOMEM); + + ret = inotify_dev_get_wd(dev, watch); + if (unlikely(ret)) { + kmem_cache_free(watch_cachep, watch); + return ERR_PTR(ret); + } + + watch->mask = mask; + atomic_set(&watch->count, 0); + INIT_LIST_HEAD(&watch->d_list); + INIT_LIST_HEAD(&watch->i_list); + + /* save a reference to device and bump the count to make it official */ + get_inotify_dev(dev); + watch->dev = dev; + + /* + * Save a reference to the inode and bump the ref count to make it + * official. We hold a reference to nameidata, which makes this safe. + */ + watch->inode = igrab(inode); + + /* bump our own count, corresponding to our entry in dev->watches */ + get_inotify_watch(watch); + + atomic_inc(&dev->user->inotify_watches); + + return watch; +} + +/* + * inotify_find_dev - find the watch associated with the given inode and dev + * + * Callers must hold inode->inotify_sem. + */ +static struct inotify_watch *inode_find_dev(struct inode *inode, + struct inotify_device *dev) +{ + struct inotify_watch *watch; + + list_for_each_entry(watch, &inode->inotify_watches, i_list) { + if (watch->dev == dev) + return watch; + } + + return NULL; +} + +/* + * remove_watch_no_event - remove_watch() without the IN_IGNORED event. + */ +static void remove_watch_no_event(struct inotify_watch *watch, + struct inotify_device *dev) +{ + list_del(&watch->i_list); + list_del(&watch->d_list); + + atomic_dec(&dev->user->inotify_watches); + idr_remove(&dev->idr, watch->wd); + put_inotify_watch(watch); +} + +/* + * remove_watch - Remove a watch from both the device and the inode. Sends + * the IN_IGNORED event to the given device signifying that the inode is no + * longer watched. + * + * Callers must hold both inode->inotify_sem and dev->sem. We drop a + * reference to the inode before returning. + * + * The inode is not iput() so as to remain atomic. If the inode needs to be + * iput(), the call returns one. Otherwise, it returns zero. + */ +static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev) +{ + inotify_dev_queue_event(dev, watch, IN_IGNORED, 0, NULL); + remove_watch_no_event(watch, dev); +} + +/* + * inotify_inode_watched - returns nonzero if there are watches on this inode + * and zero otherwise. We call this lockless, we do not care if we race. + */ +static inline int inotify_inode_watched(struct inode *inode) +{ + return !list_empty(&inode->inotify_watches); +} + +/* Kernel API */ + +/** + * inotify_inode_queue_event - queue an event to all watches on this inode + * @inode: inode event is originating from + * @mask: event mask describing this event + * @cookie: cookie for synchronization, or zero + * @name: filename, if any + */ +void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie, + const char *name) +{ + struct inotify_watch *watch, *next; + + if (!inotify_inode_watched(inode)) + return; + + down(&inode->inotify_sem); + list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { + u32 watch_mask = watch->mask; + if (watch_mask & mask) { + struct inotify_device *dev = watch->dev; + get_inotify_watch(watch); + down(&dev->sem); + inotify_dev_queue_event(dev, watch, mask, cookie, name); + if (watch_mask & IN_ONESHOT) + remove_watch_no_event(watch, dev); + up(&dev->sem); + put_inotify_watch(watch); + } + } + up(&inode->inotify_sem); +} +EXPORT_SYMBOL_GPL(inotify_inode_queue_event); + +/** + * inotify_dentry_parent_queue_event - queue an event to a dentry's parent + * @dentry: the dentry in question, we queue against this dentry's parent + * @mask: event mask describing this event + * @cookie: cookie for synchronization, or zero + * @name: filename, if any + */ +void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask, + u32 cookie, const char *name) +{ + struct dentry *parent; + struct inode *inode; + + spin_lock(&dentry->d_lock); + parent = dentry->d_parent; + inode = parent->d_inode; + + if (inotify_inode_watched(inode)) { + dget(parent); + spin_unlock(&dentry->d_lock); + inotify_inode_queue_event(inode, mask, cookie, name); + dput(parent); + } else + spin_unlock(&dentry->d_lock); +} +EXPORT_SYMBOL_GPL(inotify_dentry_parent_queue_event); + +/** + * inotify_get_cookie - return a unique cookie for use in synchronizing events. + */ +u32 inotify_get_cookie(void) +{ + return atomic_inc_return(&inotify_cookie); +} +EXPORT_SYMBOL_GPL(inotify_get_cookie); + +/** + * inotify_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_sem held, keeping shrink_icache_memory() at bay. + * We temporarily drop inode_lock, however, and CAN block. + */ +void inotify_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 inotify_watch *watch, *next_w; + struct inode *need_iput_tmp; + struct list_head *watches; + + /* + * 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; + + /* + * We cannot __iget() an inode in state I_CLEAR, I_FREEING, or + * I_WILL_FREE 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)) + continue; + + need_iput_tmp = need_iput; + need_iput = NULL; + /* In case the remove_watch() 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_sem keeps shrink_icache_memory() away. + */ + spin_unlock(&inode_lock); + + if (need_iput_tmp) + iput(need_iput_tmp); + + /* for each watch, send IN_UNMOUNT and then remove it */ + down(&inode->inotify_sem); + watches = &inode->inotify_watches; + list_for_each_entry_safe(watch, next_w, watches, i_list) { + struct inotify_device *dev = watch->dev; + down(&dev->sem); + inotify_dev_queue_event(dev, watch, IN_UNMOUNT,0,NULL); + remove_watch(watch, dev); + up(&dev->sem); + } + up(&inode->inotify_sem); + iput(inode); + + spin_lock(&inode_lock); + } +} +EXPORT_SYMBOL_GPL(inotify_unmount_inodes); + +/** + * inotify_inode_is_dead - an inode has been deleted, cleanup any watches + * @inode: inode that is about to be removed + */ +void inotify_inode_is_dead(struct inode *inode) +{ + struct inotify_watch *watch, *next; + + down(&inode->inotify_sem); + list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { + struct inotify_device *dev = watch->dev; + down(&dev->sem); + remove_watch(watch, dev); + up(&dev->sem); + } + up(&inode->inotify_sem); +} +EXPORT_SYMBOL_GPL(inotify_inode_is_dead); + +/* Device Interface */ + +static unsigned int inotify_poll(struct file *file, poll_table *wait) +{ + struct inotify_device *dev = file->private_data; + int ret = 0; + + poll_wait(file, &dev->wq, wait); + down(&dev->sem); + if (!list_empty(&dev->events)) + ret = POLLIN | POLLRDNORM; + up(&dev->sem); + + return ret; +} + +static ssize_t inotify_read(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + size_t event_size = sizeof (struct inotify_event); + struct inotify_device *dev; + char __user *start; + int ret; + DEFINE_WAIT(wait); + + start = buf; + dev = file->private_data; + + while (1) { + int events; + + prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); + + down(&dev->sem); + events = !list_empty(&dev->events); + up(&dev->sem); + if (events) { + ret = 0; + break; + } + + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + break; + } + + if (signal_pending(current)) { + ret = -EINTR; + break; + } + + schedule(); + } + + finish_wait(&dev->wq, &wait); + if (ret) + return ret; + + down(&dev->sem); + while (1) { + struct inotify_kernel_event *kevent; + + ret = buf - start; + if (list_empty(&dev->events)) + break; + + kevent = inotify_dev_get_event(dev); + if (event_size + kevent->event.len > count) + break; + + if (copy_to_user(buf, &kevent->event, event_size)) { + ret = -EFAULT; + break; + } + buf += event_size; + count -= event_size; + + if (kevent->name) { + if (copy_to_user(buf, kevent->name, kevent->event.len)){ + ret = -EFAULT; + break; + } + buf += kevent->event.len; + count -= kevent->event.len; + } + + remove_kevent(dev, kevent); + } + up(&dev->sem); + + return ret; +} + +static int inotify_release(struct inode *ignored, struct file *file) +{ + struct inotify_device *dev = file->private_data; + + /* + * Destroy all of the watches on this device. Unfortunately, not very + * pretty. We cannot do a simple iteration over the list, because we + * do not know the inode until we iterate to the watch. But we need to + * hold inode->inotify_sem before dev->sem. The following works. + */ + while (1) { + struct inotify_watch *watch; + struct list_head *watches; + struct inode *inode; + + down(&dev->sem); + watches = &dev->watches; + if (list_empty(watches)) { + up(&dev->sem); + break; + } + watch = list_entry(watches->next, struct inotify_watch, d_list); + get_inotify_watch(watch); + up(&dev->sem); + + inode = watch->inode; + down(&inode->inotify_sem); + down(&dev->sem); + remove_watch_no_event(watch, dev); + up(&dev->sem); + up(&inode->inotify_sem); + put_inotify_watch(watch); + } + + /* destroy all of the events on this device */ + down(&dev->sem); + while (!list_empty(&dev->events)) + inotify_dev_event_dequeue(dev); + up(&dev->sem); + + /* free this device: the put matching the get in inotify_open() */ + put_inotify_dev(dev); + + return 0; +} + +/* + * inotify_ignore - handle the INOTIFY_IGNORE ioctl, asking that a given wd be + * removed from the device. + * + * Can sleep. + */ +static int inotify_ignore(struct inotify_device *dev, s32 wd) +{ + struct inotify_watch *watch; + struct inode *inode; + + down(&dev->sem); + watch = idr_find(&dev->idr, wd); + if (unlikely(!watch)) { + up(&dev->sem); + return -EINVAL; + } + get_inotify_watch(watch); + inode = watch->inode; + up(&dev->sem); + + down(&inode->inotify_sem); + down(&dev->sem); + + /* make sure that we did not race */ + watch = idr_find(&dev->idr, wd); + if (likely(watch)) + remove_watch(watch, dev); + + up(&dev->sem); + up(&inode->inotify_sem); + put_inotify_watch(watch); + + return 0; +} + +static long inotify_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct inotify_device *dev; + void __user *p; + int ret = -ENOTTY; + + dev = file->private_data; + p = (void __user *) arg; + + switch (cmd) { + case FIONREAD: + ret = put_user(dev->queue_size, (int __user *) p); + break; + } + + return ret; +} + +static struct file_operations inotify_fops = { + .poll = inotify_poll, + .read = inotify_read, + .release = inotify_release, + .unlocked_ioctl = inotify_ioctl, + .compat_ioctl = inotify_ioctl, +}; + +asmlinkage long sys_inotify_init(void) +{ + struct inotify_device *dev; + struct user_struct *user; + int ret = -ENOTTY; + int fd; + struct file *filp; + + fd = get_unused_fd(); + if (fd < 0) { + ret = fd; + goto out; + } + + filp = get_empty_filp(); + if (!filp) { + put_unused_fd(fd); + ret = -ENFILE; + goto out; + } + filp->f_op = &inotify_fops; + filp->f_vfsmnt = mntget(inotify_mnt); + filp->f_dentry = dget(inotify_mnt->mnt_root); + filp->f_mapping = filp->f_dentry->d_inode->i_mapping; + filp->f_mode = FMODE_READ; + filp->f_flags = O_RDONLY; + + user = get_uid(current->user); + + if (unlikely(atomic_read(&user->inotify_devs) >= inotify_max_user_devices)) { + ret = -EMFILE; + goto out_err; + } + + dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); + if (unlikely(!dev)) { + ret = -ENOMEM; + goto out_err; + } + + idr_init(&dev->idr); + INIT_LIST_HEAD(&dev->events); + INIT_LIST_HEAD(&dev->watches); + init_waitqueue_head(&dev->wq); + sema_init(&dev->sem, 1); + 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); + atomic_inc(&user->inotify_devs); + + filp->private_data = dev; + fd_install (fd, filp); + return fd; +out_err: + put_unused_fd (fd); + put_filp (filp); + free_uid(user); +out: + return ret; +} + +asmlinkage long sys_inotify_add_watch(int fd, const char *path, u32 mask) +{ + struct inotify_watch *watch, *old; + struct inode *inode; + struct inotify_device *dev; + struct nameidata nd; + struct file *filp; + int ret; + + filp = fget(fd); + if (!filp) + return -EBADF; + + dev = filp->private_data; + + ret = find_inode ((const char __user*)path, &nd); + if (ret) + goto fput_and_out; + + /* Held in place by reference in nd */ + inode = nd.dentry->d_inode; + + down(&inode->inotify_sem); + down(&dev->sem); + + /* don't let user-space set invalid bits: we don't want flags set */ + mask &= IN_ALL_EVENTS; + if (!mask) { + ret = -EINVAL; + goto out; + } + + /* + * Handle the case of re-adding a watch on an (inode,dev) pair that we + * are already watching. We just update the mask and return its wd. + */ + old = inode_find_dev(inode, dev); + if (unlikely(old)) { + old->mask = mask; + ret = old->wd; + goto out; + } + + watch = create_watch(dev, mask, inode); + if (unlikely(IS_ERR(watch))) { + ret = PTR_ERR(watch); + goto out; + } + + /* Add the watch to the device's and the inode's list */ + list_add(&watch->d_list, &dev->watches); + list_add(&watch->i_list, &inode->inotify_watches); + ret = watch->wd; +out: + path_release (&nd); + up(&dev->sem); + up(&inode->inotify_sem); +fput_and_out: + fput(filp); + return ret; +} + +asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) +{ + struct file *filp; + struct inotify_device *dev; + int ret; + + filp = fget(fd); + if (!filp) + return -EBADF; + dev = filp->private_data; + ret = inotify_ignore (dev, wd); + fput(filp); + return ret; +} + +static struct super_block * +inotify_get_sb(struct file_system_type *fs_type, int flags, + const char *dev_name, void *data) +{ + return get_sb_pseudo(fs_type, "inotify", NULL, 0xBAD1DEA); +} + +static struct file_system_type inotify_fs_type = { + .name = "inotifyfs", + .get_sb = inotify_get_sb, + .kill_sb = kill_anon_super, +}; + +/* + * inotify_init - Our initialization function. Note that we cannnot return + * error because we have compiled-in VFS hooks. So an (unlikely) failure here + * must result in panic(). + */ +static int __init inotify_init(void) +{ + register_filesystem(&inotify_fs_type); + inotify_mnt = kern_mount(&inotify_fs_type); + + inotify_max_queued_events = 8192; + inotify_max_user_devices = 128; + inotify_max_user_watches = 8192; + + atomic_set(&inotify_cookie, 0); + + watch_cachep = kmem_cache_create("inotify_watch_cache", + sizeof(struct inotify_watch), + 0, SLAB_PANIC, NULL, NULL); + event_cachep = kmem_cache_create("inotify_event_cache", + sizeof(struct inotify_kernel_event), + 0, SLAB_PANIC, NULL, NULL); + + printk(KERN_INFO "inotify syscall\n"); + + return 0; +} + +module_init(inotify_init); -- cgit v1.2.3 From 0399cb08c54708db231d616f106f64d920e0b723 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Wed, 13 Jul 2005 12:38:18 -0400 Subject: [PATCH] inotify: move sysctl This moves the inotify sysctl knobs to "/proc/sys/fs/inotify" from "/proc/sys/fs". Also some related cleanup. Signed-off-by: Robert Love Signed-off-by: Linus Torvalds --- fs/inotify.c | 49 +++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index e423bfe0c86f..fb4803131423 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -45,8 +45,8 @@ static kmem_cache_t *event_cachep; static struct vfsmount *inotify_mnt; -/* These are configurable via /proc/sys/inotify */ -int inotify_max_user_devices; +/* these are configurable via /proc/sys/fs/inotify/ */ +int inotify_max_user_instances; int inotify_max_user_watches; int inotify_max_queued_events; @@ -125,6 +125,47 @@ struct inotify_watch { u32 mask; /* event mask for this watch */ }; +#ifdef CONFIG_SYSCTL + +#include + +static int zero; + +ctl_table inotify_table[] = { + { + .ctl_name = INOTIFY_MAX_USER_INSTANCES, + .procname = "max_user_instances", + .data = &inotify_max_user_instances, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero, + }, + { + .ctl_name = INOTIFY_MAX_USER_WATCHES, + .procname = "max_user_watches", + .data = &inotify_max_user_watches, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero, + }, + { + .ctl_name = INOTIFY_MAX_QUEUED_EVENTS, + .procname = "max_queued_events", + .data = &inotify_max_queued_events, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero + }, + { .ctl_name = 0 } +}; +#endif /* CONFIG_SYSCTL */ + static inline void get_inotify_dev(struct inotify_device *dev) { atomic_inc(&dev->count); @@ -842,7 +883,7 @@ asmlinkage long sys_inotify_init(void) user = get_uid(current->user); - if (unlikely(atomic_read(&user->inotify_devs) >= inotify_max_user_devices)) { + if (unlikely(atomic_read(&user->inotify_devs) >= inotify_max_user_instances)) { ret = -EMFILE; goto out_err; } @@ -979,7 +1020,7 @@ static int __init inotify_init(void) inotify_mnt = kern_mount(&inotify_fs_type); inotify_max_queued_events = 8192; - inotify_max_user_devices = 128; + inotify_max_user_instances = 8; inotify_max_user_watches = 8192; atomic_set(&inotify_cookie, 0); -- cgit v1.2.3 From 9a556e89081b0c1c2f83cee915363b15a68a6f2d Mon Sep 17 00:00:00 2001 From: Robert Love Date: Wed, 13 Jul 2005 13:49:23 -0400 Subject: [PATCH] inotify: misc cleanup Really simple, basic cleanup. Signed-off-by: Robert Love Signed-off-by: Linus Torvalds --- fs/inotify.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index fb4803131423..54757be888b6 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -29,8 +29,6 @@ #include #include #include -#include -#include #include #include #include @@ -934,7 +932,7 @@ asmlinkage long sys_inotify_add_watch(int fd, const char *path, u32 mask) dev = filp->private_data; - ret = find_inode ((const char __user*)path, &nd); + ret = find_inode((const char __user*) path, &nd); if (ret) goto fput_and_out; @@ -991,8 +989,9 @@ asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) if (!filp) return -EBADF; dev = filp->private_data; - ret = inotify_ignore (dev, wd); + ret = inotify_ignore(dev, wd); fput(filp); + return ret; } @@ -1032,8 +1031,6 @@ static int __init inotify_init(void) sizeof(struct inotify_kernel_event), 0, SLAB_PANIC, NULL, NULL); - printk(KERN_INFO "inotify syscall\n"); - return 0; } -- cgit v1.2.3 From b680716ed28baf549f777fb125fc23ba975985c5 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:07:13 -0400 Subject: [PATCH] inotify: misc. cleanup Miscellaneous invariant clean up, comment fixes, and so on. Trivial stuff. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 66 +++++++++++++++++++++++++++++------------------------------- 1 file changed, 32 insertions(+), 34 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index 54757be888b6..a87926584cd2 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -62,8 +62,8 @@ int inotify_max_queued_events; * Lifetimes of the three main data structures--inotify_device, inode, and * inotify_watch--are managed by reference count. * - * inotify_device: Lifetime is from open until release. Additional references - * can bump the count via get_inotify_dev() and drop the count via + * inotify_device: Lifetime is from inotify_init() until release. Additional + * references can bump the count via get_inotify_dev() and drop the count via * put_inotify_dev(). * * inotify_watch: Lifetime is from create_watch() to destory_watch(). @@ -75,7 +75,7 @@ int inotify_max_queued_events; */ /* - * struct inotify_device - represents an open instance of an inotify device + * struct inotify_device - represents an inotify instance * * This structure is protected by the semaphore 'sem'. */ @@ -371,7 +371,7 @@ static int find_inode(const char __user *dirname, struct nameidata *nd) /* you can only watch an inode if you have read permissions on it */ error = permission(nd->dentry->d_inode, MAY_READ, NULL); if (error) - path_release (nd); + path_release(nd); return error; } @@ -387,7 +387,8 @@ static struct inotify_watch *create_watch(struct inotify_device *dev, struct inotify_watch *watch; int ret; - if (atomic_read(&dev->user->inotify_watches) >= inotify_max_user_watches) + if (atomic_read(&dev->user->inotify_watches) >= + inotify_max_user_watches) return ERR_PTR(-ENOSPC); watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL); @@ -783,15 +784,14 @@ static int inotify_release(struct inode *ignored, struct file *file) inotify_dev_event_dequeue(dev); up(&dev->sem); - /* free this device: the put matching the get in inotify_open() */ + /* free this device: the put matching the get in inotify_init() */ put_inotify_dev(dev); return 0; } /* - * inotify_ignore - handle the INOTIFY_IGNORE ioctl, asking that a given wd be - * removed from the device. + * inotify_ignore - remove a given wd from this inotify instance. * * Can sleep. */ @@ -856,15 +856,12 @@ asmlinkage long sys_inotify_init(void) { struct inotify_device *dev; struct user_struct *user; - int ret = -ENOTTY; - int fd; - struct file *filp; + struct file *filp; + int fd, ret; fd = get_unused_fd(); - if (fd < 0) { - ret = fd; - goto out; - } + if (fd < 0) + return fd; filp = get_empty_filp(); if (!filp) { @@ -872,16 +869,11 @@ asmlinkage long sys_inotify_init(void) ret = -ENFILE; goto out; } - filp->f_op = &inotify_fops; - filp->f_vfsmnt = mntget(inotify_mnt); - filp->f_dentry = dget(inotify_mnt->mnt_root); - filp->f_mapping = filp->f_dentry->d_inode->i_mapping; - filp->f_mode = FMODE_READ; - filp->f_flags = O_RDONLY; user = get_uid(current->user); - if (unlikely(atomic_read(&user->inotify_devs) >= inotify_max_user_instances)) { + if (unlikely(atomic_read(&user->inotify_devs) >= + inotify_max_user_instances)) { ret = -EMFILE; goto out_err; } @@ -892,6 +884,14 @@ asmlinkage long sys_inotify_init(void) goto out_err; } + filp->f_op = &inotify_fops; + filp->f_vfsmnt = mntget(inotify_mnt); + filp->f_dentry = dget(inotify_mnt->mnt_root); + filp->f_mapping = filp->f_dentry->d_inode->i_mapping; + filp->f_mode = FMODE_READ; + filp->f_flags = O_RDONLY; + filp->private_data = dev; + idr_init(&dev->idr); INIT_LIST_HEAD(&dev->events); INIT_LIST_HEAD(&dev->watches); @@ -905,9 +905,8 @@ asmlinkage long sys_inotify_init(void) get_inotify_dev(dev); atomic_inc(&user->inotify_devs); + fd_install(fd, filp); - filp->private_data = dev; - fd_install (fd, filp); return fd; out_err: put_unused_fd (fd); @@ -917,7 +916,7 @@ out: return ret; } -asmlinkage long sys_inotify_add_watch(int fd, const char *path, u32 mask) +asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) { struct inotify_watch *watch, *old; struct inode *inode; @@ -930,21 +929,20 @@ asmlinkage long sys_inotify_add_watch(int fd, const char *path, u32 mask) if (!filp) return -EBADF; - dev = filp->private_data; - - ret = find_inode((const char __user*) path, &nd); - if (ret) + ret = find_inode(path, &nd); + if (unlikely(ret)) goto fput_and_out; - /* Held in place by reference in nd */ + /* inode held in place by reference to nd; dev by fget on fd */ inode = nd.dentry->d_inode; + dev = filp->private_data; down(&inode->inotify_sem); down(&dev->sem); /* don't let user-space set invalid bits: we don't want flags set */ mask &= IN_ALL_EVENTS; - if (!mask) { + if (unlikely(!mask)) { ret = -EINVAL; goto out; } @@ -1009,11 +1007,11 @@ static struct file_system_type inotify_fs_type = { }; /* - * inotify_init - Our initialization function. Note that we cannnot return + * inotify_setup - Our initialization function. Note that we cannnot return * error because we have compiled-in VFS hooks. So an (unlikely) failure here * must result in panic(). */ -static int __init inotify_init(void) +static int __init inotify_setup(void) { register_filesystem(&inotify_fs_type); inotify_mnt = kern_mount(&inotify_fs_type); @@ -1034,4 +1032,4 @@ static int __init inotify_init(void) return 0; } -module_init(inotify_init); +module_init(inotify_setup); -- cgit v1.2.3 From 33ea2f52b8758ef62ae4a9d2f91821c47d999ee9 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:08:37 -0400 Subject: [PATCH] inotify: use fget_light As an optimization, use fget_light() and fput_light() where possible. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index a87926584cd2..807209f0bcda 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -923,10 +923,10 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) struct inotify_device *dev; struct nameidata nd; struct file *filp; - int ret; + int ret, fput_needed; - filp = fget(fd); - if (!filp) + filp = fget_light(fd, &fput_needed); + if (unlikely(!filp)) return -EBADF; ret = find_inode(path, &nd); @@ -973,7 +973,7 @@ out: up(&dev->sem); up(&inode->inotify_sem); fput_and_out: - fput(filp); + fput_light(filp, fput_needed); return ret; } @@ -981,14 +981,14 @@ asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) { struct file *filp; struct inotify_device *dev; - int ret; + int ret, fput_needed; - filp = fget(fd); - if (!filp) + filp = fget_light(fd, &fput_needed); + if (unlikely(!filp)) return -EBADF; dev = filp->private_data; ret = inotify_ignore(dev, wd); - fput(filp); + fput_light(filp, fput_needed); return ret; } -- cgit v1.2.3 From 783bc29bbc5d6625a4669d3eb1d989a8fb275d43 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:10:08 -0400 Subject: [PATCH] inotify: oops fix Bug fix: Ensure that the fd passed to inotify_add_watch() and inotify_rm_watch() belongs to inotify. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index 807209f0bcda..b55d6e4a0911 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -929,6 +929,12 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) if (unlikely(!filp)) return -EBADF; + /* verify that this is indeed an inotify instance */ + if (unlikely(filp->f_op != &inotify_fops)) { + ret = -EINVAL; + goto fput_and_out; + } + ret = find_inode(path, &nd); if (unlikely(ret)) goto fput_and_out; @@ -986,10 +992,18 @@ asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) filp = fget_light(fd, &fput_needed); if (unlikely(!filp)) return -EBADF; + + /* verify that this is indeed an inotify instance */ + if (unlikely(filp->f_op != &inotify_fops)) { + ret = -EINVAL; + goto out; + } + dev = filp->private_data; ret = inotify_ignore(dev, wd); - fput_light(filp, fput_needed); +out: + fput_light(filp, fput_needed); return ret; } -- cgit v1.2.3 From 5eb22cbcdb849886c2584389faff5afb56c23876 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:12:19 -0400 Subject: [PATCH] inotify: exit path cleanups Handle error out paths better. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index b55d6e4a0911..d41c53c8dfd0 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -865,23 +865,21 @@ asmlinkage long sys_inotify_init(void) filp = get_empty_filp(); if (!filp) { - put_unused_fd(fd); ret = -ENFILE; - goto out; + goto out_put_fd; } user = get_uid(current->user); - if (unlikely(atomic_read(&user->inotify_devs) >= inotify_max_user_instances)) { ret = -EMFILE; - goto out_err; + goto out_free_uid; } dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); if (unlikely(!dev)) { ret = -ENOMEM; - goto out_err; + goto out_free_uid; } filp->f_op = &inotify_fops; @@ -908,11 +906,11 @@ asmlinkage long sys_inotify_init(void) fd_install(fd, filp); return fd; -out_err: - put_unused_fd (fd); - put_filp (filp); +out_free_uid: free_uid(user); -out: + put_filp(filp); +out_put_fd: + put_unused_fd(fd); return ret; } @@ -975,9 +973,9 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) list_add(&watch->i_list, &inode->inotify_watches); ret = watch->wd; out: - path_release (&nd); up(&dev->sem); up(&inode->inotify_sem); + path_release(&nd); fput_and_out: fput_light(filp, fput_needed); return ret; -- cgit v1.2.3 From 1b2ccf0cc15af717263c7cfe5d0aaf5ac057489e Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:13:43 -0400 Subject: [PATCH] inotify: change default limits Change default inotify limits: Maximum instances per user to 128 and maximum events per queue to 16k. The max instances used to be 128; the change to 8 was a mistake. Memory consumption is fine. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index d41c53c8dfd0..6a0ba2c858e6 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -1028,8 +1028,8 @@ static int __init inotify_setup(void) register_filesystem(&inotify_fs_type); inotify_mnt = kern_mount(&inotify_fs_type); - inotify_max_queued_events = 8192; - inotify_max_user_instances = 8; + inotify_max_queued_events = 16384; + inotify_max_user_instances = 128; inotify_max_user_watches = 8192; atomic_set(&inotify_cookie, 0); -- cgit v1.2.3 From e5ca844a9d795e97c08bc7901c62a48c28469eb0 Mon Sep 17 00:00:00 2001 From: Robert Love Date: Mon, 25 Jul 2005 15:17:34 -0400 Subject: [PATCH] inotify: check retval in init Check for (unlikely) errors in the filesystem initialization stuff in our module_init() function. Signed-off-by: Robert Love Signed-off-by: John McCutchan Signed-off-by: Linus Torvalds --- fs/inotify.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index 6a0ba2c858e6..cdfff9067149 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -1025,8 +1025,15 @@ static struct file_system_type inotify_fs_type = { */ static int __init inotify_setup(void) { - register_filesystem(&inotify_fs_type); + int ret; + + ret = register_filesystem(&inotify_fs_type); + if (unlikely(ret)) + panic("inotify: register_filesystem returned %d!\n", ret); + inotify_mnt = kern_mount(&inotify_fs_type); + if (unlikely(PTR_ERR(inotify_mnt))) + panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); inotify_max_queued_events = 16384; inotify_max_user_instances = 128; -- cgit v1.2.3 From 89373de7dd010832d8b68cb37dabb33ff5a688bb Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 26 Jul 2005 14:08:38 -0700 Subject: [PATCH] inotify: fix oops fix Cc: Robert Love Cc: John McCutchan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/inotify.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index cdfff9067149..a8a714e48140 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -1032,7 +1032,7 @@ static int __init inotify_setup(void) panic("inotify: register_filesystem returned %d!\n", ret); inotify_mnt = kern_mount(&inotify_fs_type); - if (unlikely(PTR_ERR(inotify_mnt))) + if (IS_ERR(inotify_mnt)) panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); inotify_max_queued_events = 16384; -- cgit v1.2.3 From b9c55d29e9fced1eb1b4c252b2efd4b55a0c3c7f Mon Sep 17 00:00:00 2001 From: John McCutchan Date: Mon, 1 Aug 2005 11:00:45 -0400 Subject: [PATCH] inotify: fix race between the kernel and user space When you rm a watch, an IN_IGNORED event is sent down the event queue with the watch descriptor that you just rm'd. If you then add a watch you could get the ignored watch's wd and if you haven't read the entire event queue, user space will think that it's newly created watch was just ignored. To avoid this problem we just use idr_get_new_above instead of idr_get_new. Signed-off-by: John McCutchan Signed-off-by: Robert Love Signed-off-by: Linus Torvalds --- fs/inotify.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/inotify.c') diff --git a/fs/inotify.c b/fs/inotify.c index a8a714e48140..27ebcac5e07f 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -90,6 +90,7 @@ struct inotify_device { 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 */ + u32 last_wd; /* the last wd allocated */ }; /* @@ -352,7 +353,7 @@ static int inotify_dev_get_wd(struct inotify_device *dev, do { if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL))) return -ENOSPC; - ret = idr_get_new(&dev->idr, watch, &watch->wd); + ret = idr_get_new_above(&dev->idr, watch, dev->last_wd, &watch->wd); } while (ret == -EAGAIN); return ret; @@ -401,6 +402,7 @@ static struct inotify_watch *create_watch(struct inotify_device *dev, return ERR_PTR(ret); } + dev->last_wd = ret; watch->mask = mask; atomic_set(&watch->count, 0); INIT_LIST_HEAD(&watch->d_list); @@ -899,6 +901,7 @@ asmlinkage long sys_inotify_init(void) dev->queue_size = 0; dev->max_events = inotify_max_queued_events; dev->user = user; + dev->last_wd = 0; atomic_set(&dev->count, 0); get_inotify_dev(dev); -- cgit v1.2.3