X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Finotify.c;h=f5099d86fd91fba6d3574e804be85a26e2201d68;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=3041503bde02f918382cacc49ec97275d1994b1f;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/fs/inotify.c b/fs/inotify.c index 3041503bd..f5099d86f 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -5,7 +5,10 @@ * John McCutchan * Robert Love * + * Kernel API added by: Amy Griffis + * * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. * * 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 @@ -20,429 +23,184 @@ #include #include -#include #include #include #include #include -#include -#include -#include -#include +#include #include #include #include #include -#include - -#include static atomic_t inotify_cookie; -static atomic_t inotify_watches; - -static kmem_cache_t *watch_cachep; -static kmem_cache_t *event_cachep; - -static struct vfsmount *inotify_mnt; - -/* these are configurable via /proc/sys/fs/inotify/ */ -int inotify_max_user_instances; -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()) + * iprune_mutex (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) + * inode->inotify_mutex (protects inode->inotify_watches and watches->i_list) + * inotify_handle->mutex (protects inotify_handle and watches->h_list) + * + * The inode->inotify_mutex and inotify_handle->mutex and held during execution + * of a caller's event handler. Thus, the caller must not hold any locks + * taken in their event handler while calling any of the published inotify + * interfaces. */ /* - * Lifetimes of the three main data structures--inotify_device, inode, and + * Lifetimes of the three main data structures--inotify_handle, inode, and * inotify_watch--are managed by reference count. * - * 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_handle: Lifetime is from inotify_init() to inotify_destroy(). + * Additional references can bump the count via get_inotify_handle() and drop + * the count via put_inotify_handle(). * - * 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(). + * inotify_watch: for inotify's purposes, lifetime is from inotify_add_watch() + * to remove_watch_no_event(). Additional references can bump the count via + * get_inotify_watch() and drop the count via put_inotify_watch(). The caller + * is reponsible for the final put after receiving IN_IGNORED, or when using + * IN_ONESHOT after receiving the first event. Inotify does the final put if + * inotify_destroy() is called. * * inode: Pinned so long as the inode is associated with a watch, from - * create_watch() to put_inotify_watch(). + * inotify_add_watch() to the final put_inotify_watch(). */ /* - * struct inotify_device - represents an inotify instance + * struct inotify_handle - represents an inotify instance * - * This structure is protected by the semaphore 'sem'. + * This structure is protected by the mutex 'mutex'. */ -struct inotify_device { - wait_queue_head_t wq; /* wait queue for i/o */ +struct inotify_handle { struct idr idr; /* idr mapping wd -> watch */ - struct semaphore sem; /* protects this bad boy */ - struct list_head events; /* list of queued events */ + struct mutex mutex; /* protects this bad boy */ 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 */ u32 last_wd; /* the last wd allocated */ + const struct inotify_operations *in_ops; /* inotify caller operations */ }; -/* - * 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 */ -}; - -#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) +static inline void get_inotify_handle(struct inotify_handle *ih) { - atomic_inc(&dev->count); + atomic_inc(&ih->count); } -static inline void put_inotify_dev(struct inotify_device *dev) +static inline void put_inotify_handle(struct inotify_handle *ih) { - if (atomic_dec_and_test(&dev->count)) { - atomic_dec(&dev->user->inotify_devs); - free_uid(dev->user); - idr_destroy(&dev->idr); - kfree(dev); + if (atomic_dec_and_test(&ih->count)) { + idr_destroy(&ih->idr); + kfree(ih); } } -static inline void get_inotify_watch(struct inotify_watch *watch) +/** + * get_inotify_watch - grab a reference to an inotify_watch + * @watch: watch to grab + */ +void get_inotify_watch(struct inotify_watch *watch) { atomic_inc(&watch->count); } +EXPORT_SYMBOL_GPL(get_inotify_watch); -/* +/** * put_inotify_watch - decrements the ref count on a given watch. cleans up - * the watch and its references if the count reaches zero. + * watch references if the count reaches zero. inotify_watch is freed by + * inotify callers via the destroy_watch() op. + * @watch: watch to release */ -static inline void put_inotify_watch(struct inotify_watch *watch) +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); -} + struct inotify_handle *ih = watch->ih; -/* - * 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); + iput(watch->inode); + ih->in_ops->destroy_watch(watch); + put_inotify_handle(ih); } } +EXPORT_SYMBOL_GPL(put_inotify_watch); /* - * inotify_dev_get_wd - returns the next WD for use by the given dev + * inotify_handle_get_wd - returns the next WD for use by the given handle * - * Callers must hold dev->sem. This function can sleep. + * Callers must hold ih->mutex. This function can sleep. */ -static int inotify_dev_get_wd(struct inotify_device *dev, - struct inotify_watch *watch) +static int inotify_handle_get_wd(struct inotify_handle *ih, + struct inotify_watch *watch) { int ret; do { - if (unlikely(!idr_pre_get(&dev->idr, GFP_KERNEL))) + if (unlikely(!idr_pre_get(&ih->idr, GFP_KERNEL))) return -ENOSPC; - ret = idr_get_new_above(&dev->idr, watch, dev->last_wd+1, &watch->wd); + ret = idr_get_new_above(&ih->idr, watch, ih->last_wd+1, &watch->wd); } while (ret == -EAGAIN); + if (likely(!ret)) + ih->last_wd = watch->wd; + return ret; } /* - * find_inode - resolve a user-given path to a specific inode and return a nd + * 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 int find_inode(const char __user *dirname, struct nameidata *nd, - unsigned flags) +static inline int inotify_inode_watched(struct inode *inode) { - int error; - - error = __user_walk(dirname, flags, nd); - if (error) - return error; - /* you can only watch an inode if you have read permissions on it */ - error = vfs_permission(nd, MAY_READ); - if (error) - path_release(nd); - return error; + return !list_empty(&inode->inotify_watches); } /* - * 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. + * Get child dentry flag into synch with parent inode. + * Flag should always be clear for negative dentrys. */ -static struct inotify_watch *create_watch(struct inotify_device *dev, - u32 mask, struct inode *inode) +static void set_dentry_child_flags(struct inode *inode, int watched) { - struct inotify_watch *watch; - int ret; + struct dentry *alias; - if (atomic_read(&dev->user->inotify_watches) >= - inotify_max_user_watches) - return ERR_PTR(-ENOSPC); + spin_lock(&dcache_lock); + list_for_each_entry(alias, &inode->i_dentry, d_alias) { + struct dentry *child; - 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); + list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { + if (!child->d_inode) { + WARN_ON(child->d_flags & DCACHE_INOTIFY_PARENT_WATCHED); + continue; + } + spin_lock(&child->d_lock); + if (watched) { + WARN_ON(child->d_flags & + DCACHE_INOTIFY_PARENT_WATCHED); + child->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; + } else { + WARN_ON(!(child->d_flags & + DCACHE_INOTIFY_PARENT_WATCHED)); + child->d_flags&=~DCACHE_INOTIFY_PARENT_WATCHED; + } + spin_unlock(&child->d_lock); + } } - - dev->last_wd = watch->wd; - 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); - atomic_inc(&inotify_watches); - - return watch; + spin_unlock(&dcache_lock); } /* - * inotify_find_dev - find the watch associated with the given inode and dev + * inotify_find_handle - find the watch associated with the given inode and + * handle * - * Callers must hold inode->inotify_sem. + * Callers must hold inode->inotify_mutex. */ -static struct inotify_watch *inode_find_dev(struct inode *inode, - struct inotify_device *dev) +static struct inotify_watch *inode_find_handle(struct inode *inode, + struct inotify_handle *ih) { struct inotify_watch *watch; list_for_each_entry(watch, &inode->inotify_watches, i_list) { - if (watch->dev == dev) + if (watch->ih == ih) return watch; } @@ -450,47 +208,72 @@ static struct inotify_watch *inode_find_dev(struct inode *inode, } /* - * remove_watch_no_event - remove_watch() without the IN_IGNORED event. + * remove_watch_no_event - remove watch without the IN_IGNORED event. + * + * Callers must hold both inode->inotify_mutex and ih->mutex. */ static void remove_watch_no_event(struct inotify_watch *watch, - struct inotify_device *dev) + struct inotify_handle *ih) { list_del(&watch->i_list); - list_del(&watch->d_list); + list_del(&watch->h_list); - atomic_dec(&dev->user->inotify_watches); - atomic_dec(&inotify_watches); - idr_remove(&dev->idr, watch->wd); - put_inotify_watch(watch); + if (!inotify_inode_watched(watch->inode)) + set_dentry_child_flags(watch->inode, 0); + + idr_remove(&ih->idr, watch->wd); } -/* - * 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. +/** + * inotify_remove_watch_locked - Remove a watch from both the handle and the + * inode. Sends the IN_IGNORED event signifying that the inode is no longer + * watched. May be invoked from a caller's event handler. + * @ih: inotify handle associated with watch + * @watch: watch to remove * - * 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. + * Callers must hold both inode->inotify_mutex and ih->mutex. */ -static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev) +void inotify_remove_watch_locked(struct inotify_handle *ih, + struct inotify_watch *watch) { - inotify_dev_queue_event(dev, watch, IN_IGNORED, 0, NULL); - remove_watch_no_event(watch, dev); + remove_watch_no_event(watch, ih); + ih->in_ops->handle_event(watch, watch->wd, IN_IGNORED, 0, NULL, NULL); } +EXPORT_SYMBOL_GPL(inotify_remove_watch_locked); + +/* Kernel API for producing events */ /* - * 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. + * inotify_d_instantiate - instantiate dcache entry for inode */ -static inline int inotify_inode_watched(struct inode *inode) +void inotify_d_instantiate(struct dentry *entry, struct inode *inode) { - return !list_empty(&inode->inotify_watches); + struct dentry *parent; + + if (!inode) + return; + + WARN_ON(entry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED); + spin_lock(&entry->d_lock); + parent = entry->d_parent; + if (parent->d_inode && inotify_inode_watched(parent->d_inode)) + entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; + spin_unlock(&entry->d_lock); } -/* Kernel API */ +/* + * inotify_d_move - dcache entry has been moved + */ +void inotify_d_move(struct dentry *entry) +{ + struct dentry *parent; + + parent = entry->d_parent; + if (inotify_inode_watched(parent->d_inode)) + entry->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; + else + entry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED; +} /** * inotify_inode_queue_event - queue an event to all watches on this inode @@ -498,30 +281,30 @@ static inline int inotify_inode_watched(struct inode *inode) * @mask: event mask describing this event * @cookie: cookie for synchronization, or zero * @name: filename, if any + * @n_inode: inode associated with name */ void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie, - const char *name) + const char *name, struct inode *n_inode) { struct inotify_watch *watch, *next; if (!inotify_inode_watched(inode)) return; - down(&inode->inotify_sem); + mutex_lock(&inode->inotify_mutex); 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); + struct inotify_handle *ih= watch->ih; + mutex_lock(&ih->mutex); if (watch_mask & IN_ONESHOT) - remove_watch_no_event(watch, dev); - up(&dev->sem); - put_inotify_watch(watch); + remove_watch_no_event(watch, ih); + ih->in_ops->handle_event(watch, watch->wd, mask, cookie, + name, n_inode); + mutex_unlock(&ih->mutex); } } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); } EXPORT_SYMBOL_GPL(inotify_inode_queue_event); @@ -538,7 +321,7 @@ void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask, struct dentry *parent; struct inode *inode; - if (!atomic_read (&inotify_watches)) + if (!(dentry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED)) return; spin_lock(&dentry->d_lock); @@ -548,7 +331,8 @@ void inotify_dentry_parent_queue_event(struct dentry *dentry, u32 mask, if (inotify_inode_watched(inode)) { dget(parent); spin_unlock(&dentry->d_lock); - inotify_inode_queue_event(inode, mask, cookie, name); + inotify_inode_queue_event(inode, mask, cookie, name, + dentry->d_inode); dput(parent); } else spin_unlock(&dentry->d_lock); @@ -569,7 +353,7 @@ EXPORT_SYMBOL_GPL(inotify_get_cookie); * @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. + * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay. * We temporarily drop inode_lock, however, and CAN block. */ void inotify_unmount_inodes(struct list_head *list) @@ -600,7 +384,7 @@ void inotify_unmount_inodes(struct list_head *list) need_iput_tmp = need_iput; need_iput = NULL; - /* In case the remove_watch() drops a reference. */ + /* In case inotify_remove_watch_locked() drops a reference. */ if (inode != need_iput_tmp) __iget(inode); else @@ -618,7 +402,7 @@ void inotify_unmount_inodes(struct list_head *list) * 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. + * iprune_mutex keeps shrink_icache_memory() away. */ spin_unlock(&inode_lock); @@ -626,16 +410,17 @@ void inotify_unmount_inodes(struct list_head *list) iput(need_iput_tmp); /* for each watch, send IN_UNMOUNT and then remove it */ - down(&inode->inotify_sem); + mutex_lock(&inode->inotify_mutex); 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); + struct inotify_handle *ih= watch->ih; + mutex_lock(&ih->mutex); + ih->in_ops->handle_event(watch, watch->wd, IN_UNMOUNT, 0, + NULL, NULL); + inotify_remove_watch_locked(ih, watch); + mutex_unlock(&ih->mutex); } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); iput(inode); spin_lock(&inode_lock); @@ -651,428 +436,293 @@ void inotify_inode_is_dead(struct inode *inode) { struct inotify_watch *watch, *next; - down(&inode->inotify_sem); + mutex_lock(&inode->inotify_mutex); 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); + struct inotify_handle *ih = watch->ih; + mutex_lock(&ih->mutex); + inotify_remove_watch_locked(ih, watch); + mutex_unlock(&ih->mutex); } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); } EXPORT_SYMBOL_GPL(inotify_inode_is_dead); -/* Device Interface */ +/* Kernel Consumer API */ -static unsigned int inotify_poll(struct file *file, poll_table *wait) +/** + * inotify_init - allocate and initialize an inotify instance + * @ops: caller's inotify operations + */ +struct inotify_handle *inotify_init(const struct inotify_operations *ops) { - struct inotify_device *dev = file->private_data; - int ret = 0; + struct inotify_handle *ih; - poll_wait(file, &dev->wq, wait); - down(&dev->sem); - if (!list_empty(&dev->events)) - ret = POLLIN | POLLRDNORM; - up(&dev->sem); + ih = kmalloc(sizeof(struct inotify_handle), GFP_KERNEL); + if (unlikely(!ih)) + return ERR_PTR(-ENOMEM); - return ret; + idr_init(&ih->idr); + INIT_LIST_HEAD(&ih->watches); + mutex_init(&ih->mutex); + ih->last_wd = 0; + ih->in_ops = ops; + atomic_set(&ih->count, 0); + get_inotify_handle(ih); + + return ih; } +EXPORT_SYMBOL_GPL(inotify_init); -static ssize_t inotify_read(struct file *file, char __user *buf, - size_t count, loff_t *pos) +/** + * inotify_init_watch - initialize an inotify watch + * @watch: watch to initialize + */ +void inotify_init_watch(struct inotify_watch *watch) { - 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; + INIT_LIST_HEAD(&watch->h_list); + INIT_LIST_HEAD(&watch->i_list); + atomic_set(&watch->count, 0); + get_inotify_watch(watch); /* initial get */ } +EXPORT_SYMBOL_GPL(inotify_init_watch); -static int inotify_release(struct inode *ignored, struct file *file) +/** + * inotify_destroy - clean up and destroy an inotify instance + * @ih: inotify handle + */ +void inotify_destroy(struct inotify_handle *ih) { - struct inotify_device *dev = file->private_data; - /* - * Destroy all of the watches on this device. Unfortunately, not very + * Destroy all of the watches for this handle. 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. + * hold inode->inotify_mutex before ih->mutex. The following works. */ while (1) { struct inotify_watch *watch; struct list_head *watches; struct inode *inode; - down(&dev->sem); - watches = &dev->watches; + mutex_lock(&ih->mutex); + watches = &ih->watches; if (list_empty(watches)) { - up(&dev->sem); + mutex_unlock(&ih->mutex); break; } - watch = list_entry(watches->next, struct inotify_watch, d_list); + watch = list_entry(watches->next, struct inotify_watch, h_list); get_inotify_watch(watch); - up(&dev->sem); + mutex_unlock(&ih->mutex); 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); - } + mutex_lock(&inode->inotify_mutex); + mutex_lock(&ih->mutex); - /* destroy all of the events on this device */ - down(&dev->sem); - while (!list_empty(&dev->events)) - inotify_dev_event_dequeue(dev); - up(&dev->sem); + /* make sure we didn't race with another list removal */ + if (likely(idr_find(&ih->idr, watch->wd))) { + remove_watch_no_event(watch, ih); + put_inotify_watch(watch); + } - /* free this device: the put matching the get in inotify_init() */ - put_inotify_dev(dev); + mutex_unlock(&ih->mutex); + mutex_unlock(&inode->inotify_mutex); + put_inotify_watch(watch); + } - return 0; + /* free this handle: the put matching the get in inotify_init() */ + put_inotify_handle(ih); } +EXPORT_SYMBOL_GPL(inotify_destroy); -/* - * inotify_ignore - remove a given wd from this inotify instance. +/** + * inotify_find_watch - find an existing watch for an (ih,inode) pair + * @ih: inotify handle + * @inode: inode to watch + * @watchp: pointer to existing inotify_watch * - * Can sleep. + * Caller must pin given inode (via nameidata). */ -static int inotify_ignore(struct inotify_device *dev, s32 wd) +s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, + struct inotify_watch **watchp) { - 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); + struct inotify_watch *old; + int ret = -ENOENT; - down(&inode->inotify_sem); - down(&dev->sem); + mutex_lock(&inode->inotify_mutex); + mutex_lock(&ih->mutex); - /* make sure that we did not race */ - watch = idr_find(&dev->idr, wd); - if (likely(watch)) - remove_watch(watch, dev); + old = inode_find_handle(inode, ih); + if (unlikely(old)) { + get_inotify_watch(old); /* caller must put watch */ + *watchp = old; + ret = old->wd; + } - up(&dev->sem); - up(&inode->inotify_sem); - put_inotify_watch(watch); + mutex_unlock(&ih->mutex); + mutex_unlock(&inode->inotify_mutex); - return 0; + return ret; } +EXPORT_SYMBOL_GPL(inotify_find_watch); -static long inotify_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) +/** + * inotify_find_update_watch - find and update the mask of an existing watch + * @ih: inotify handle + * @inode: inode's watch to update + * @mask: mask of events to watch + * + * Caller must pin given inode (via nameidata). + */ +s32 inotify_find_update_watch(struct inotify_handle *ih, struct inode *inode, + u32 mask) { - 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; - } + struct inotify_watch *old; + int mask_add = 0; + int ret; - return ret; -} + if (mask & IN_MASK_ADD) + mask_add = 1; -static struct file_operations inotify_fops = { - .poll = inotify_poll, - .read = inotify_read, - .release = inotify_release, - .unlocked_ioctl = inotify_ioctl, - .compat_ioctl = inotify_ioctl, -}; + /* don't allow invalid bits: we don't want flags set */ + mask &= IN_ALL_EVENTS | IN_ONESHOT; + if (unlikely(!mask)) + return -EINVAL; -asmlinkage long sys_inotify_init(void) -{ - struct inotify_device *dev; - struct user_struct *user; - struct file *filp; - int fd, ret; - - fd = get_unused_fd(); - if (fd < 0) - return fd; - - filp = get_empty_filp(); - if (!filp) { - ret = -ENFILE; - goto out_put_fd; - } + mutex_lock(&inode->inotify_mutex); + mutex_lock(&ih->mutex); - user = get_uid(current->user); - if (unlikely(atomic_read(&user->inotify_devs) >= - inotify_max_user_instances)) { - ret = -EMFILE; - goto out_free_uid; - } - - dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL); - if (unlikely(!dev)) { - ret = -ENOMEM; - goto out_free_uid; + /* + * Handle the case of re-adding a watch on an (inode,ih) pair that we + * are already watching. We just update the mask and return its wd. + */ + old = inode_find_handle(inode, ih); + if (unlikely(!old)) { + ret = -ENOENT; + 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; - filp->private_data = dev; - - 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; - dev->last_wd = 0; - atomic_set(&dev->count, 0); - - get_inotify_dev(dev); - atomic_inc(&user->inotify_devs); - fd_install(fd, filp); - - return fd; -out_free_uid: - free_uid(user); - put_filp(filp); -out_put_fd: - put_unused_fd(fd); + if (mask_add) + old->mask |= mask; + else + old->mask = mask; + ret = old->wd; +out: + mutex_unlock(&ih->mutex); + mutex_unlock(&inode->inotify_mutex); return ret; } +EXPORT_SYMBOL_GPL(inotify_find_update_watch); -asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) +/** + * inotify_add_watch - add a watch to an inotify instance + * @ih: inotify handle + * @watch: caller allocated watch structure + * @inode: inode to watch + * @mask: mask of events to watch + * + * Caller must pin given inode (via nameidata). + * Caller must ensure it only calls inotify_add_watch() once per watch. + * Calls inotify_handle_get_wd() so may sleep. + */ +s32 inotify_add_watch(struct inotify_handle *ih, struct inotify_watch *watch, + struct inode *inode, u32 mask) { - struct inotify_watch *watch, *old; - struct inode *inode; - struct inotify_device *dev; - struct nameidata nd; - struct file *filp; - int ret, fput_needed; - int mask_add = 0; - unsigned flags = 0; - - filp = fget_light(fd, &fput_needed); - if (unlikely(!filp)) - return -EBADF; + int ret = 0; - /* verify that this is indeed an inotify instance */ - if (unlikely(filp->f_op != &inotify_fops)) { - ret = -EINVAL; - goto fput_and_out; - } + /* don't allow invalid bits: we don't want flags set */ + mask &= IN_ALL_EVENTS | IN_ONESHOT; + if (unlikely(!mask)) + return -EINVAL; + watch->mask = mask; - if (!(mask & IN_DONT_FOLLOW)) - flags |= LOOKUP_FOLLOW; - if (mask & IN_ONLYDIR) - flags |= LOOKUP_DIRECTORY; + mutex_lock(&inode->inotify_mutex); + mutex_lock(&ih->mutex); - ret = find_inode(path, &nd, flags); + /* Initialize a new watch */ + ret = inotify_handle_get_wd(ih, watch); if (unlikely(ret)) - goto fput_and_out; - - /* 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); - - if (mask & IN_MASK_ADD) - mask_add = 1; - - /* don't let user-space set invalid bits: we don't want flags set */ - mask &= IN_ALL_EVENTS | IN_ONESHOT; - if (unlikely(!mask)) { - ret = -EINVAL; goto out; - } + ret = watch->wd; + + /* save a reference to handle and bump the count to make it official */ + get_inotify_handle(ih); + watch->ih = ih; /* - * 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. + * 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. */ - old = inode_find_dev(inode, dev); - if (unlikely(old)) { - if (mask_add) - old->mask |= mask; - else - old->mask = mask; - ret = old->wd; - goto out; - } + watch->inode = igrab(inode); - watch = create_watch(dev, mask, inode); - if (unlikely(IS_ERR(watch))) { - ret = PTR_ERR(watch); - goto out; - } + if (!inotify_inode_watched(inode)) + set_dentry_child_flags(inode, 1); - /* Add the watch to the device's and the inode's list */ - list_add(&watch->d_list, &dev->watches); + /* Add the watch to the handle's and the inode's list */ + list_add(&watch->h_list, &ih->watches); list_add(&watch->i_list, &inode->inotify_watches); - ret = watch->wd; out: - up(&dev->sem); - up(&inode->inotify_sem); - path_release(&nd); -fput_and_out: - fput_light(filp, fput_needed); + mutex_unlock(&ih->mutex); + mutex_unlock(&inode->inotify_mutex); return ret; } +EXPORT_SYMBOL_GPL(inotify_add_watch); -asmlinkage long sys_inotify_rm_watch(int fd, u32 wd) +/** + * inotify_rm_wd - remove a watch from an inotify instance + * @ih: inotify handle + * @wd: watch descriptor to remove + * + * Can sleep. + */ +int inotify_rm_wd(struct inotify_handle *ih, u32 wd) { - struct file *filp; - struct inotify_device *dev; - int ret, fput_needed; - - filp = fget_light(fd, &fput_needed); - if (unlikely(!filp)) - return -EBADF; + struct inotify_watch *watch; + struct inode *inode; - /* verify that this is indeed an inotify instance */ - if (unlikely(filp->f_op != &inotify_fops)) { - ret = -EINVAL; - goto out; + mutex_lock(&ih->mutex); + watch = idr_find(&ih->idr, wd); + if (unlikely(!watch)) { + mutex_unlock(&ih->mutex); + return -EINVAL; } + get_inotify_watch(watch); + inode = watch->inode; + mutex_unlock(&ih->mutex); - dev = filp->private_data; - ret = inotify_ignore(dev, wd); + mutex_lock(&inode->inotify_mutex); + mutex_lock(&ih->mutex); -out: - fput_light(filp, fput_needed); - return ret; + /* make sure that we did not race */ + if (likely(idr_find(&ih->idr, wd) == watch)) + inotify_remove_watch_locked(ih, watch); + + mutex_unlock(&ih->mutex); + mutex_unlock(&inode->inotify_mutex); + put_inotify_watch(watch); + + return 0; } +EXPORT_SYMBOL_GPL(inotify_rm_wd); -static struct super_block * -inotify_get_sb(struct file_system_type *fs_type, int flags, - const char *dev_name, void *data) +/** + * inotify_rm_watch - remove a watch from an inotify instance + * @ih: inotify handle + * @watch: watch to remove + * + * Can sleep. + */ +int inotify_rm_watch(struct inotify_handle *ih, + struct inotify_watch *watch) { - return get_sb_pseudo(fs_type, "inotify", NULL, 0xBAD1DEA); + return inotify_rm_wd(ih, watch->wd); } - -static struct file_system_type inotify_fs_type = { - .name = "inotifyfs", - .get_sb = inotify_get_sb, - .kill_sb = kill_anon_super, -}; +EXPORT_SYMBOL_GPL(inotify_rm_watch); /* - * 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(). + * inotify_setup - core initialization function */ static int __init inotify_setup(void) { - 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 (IS_ERR(inotify_mnt)) - panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt)); - - inotify_max_queued_events = 16384; - inotify_max_user_instances = 128; - inotify_max_user_watches = 8192; - atomic_set(&inotify_cookie, 0); - atomic_set(&inotify_watches, 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); return 0; }