X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Finotify.c;h=732ec4bd5774507f8c06c6e05cc90d4d2004a84b;hb=5b4b7a236e7787f16af4e15a6253d46d8e794be6;hp=3041503bde02f918382cacc49ec97275d1994b1f;hpb=b05005772f34497eb2b7415a651fe785cbe70e16;p=linux-2.6-omap-h63xx.git diff --git a/fs/inotify.c b/fs/inotify.c index 3041503bde0..732ec4bd577 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -38,26 +38,25 @@ #include static atomic_t inotify_cookie; -static atomic_t inotify_watches; -static kmem_cache_t *watch_cachep; -static kmem_cache_t *event_cachep; +static kmem_cache_t *watch_cachep __read_mostly; +static kmem_cache_t *event_cachep __read_mostly; -static struct vfsmount *inotify_mnt; +static struct vfsmount *inotify_mnt __read_mostly; /* these are configurable via /proc/sys/fs/inotify/ */ -int inotify_max_user_instances; -int inotify_max_user_watches; -int inotify_max_queued_events; +int inotify_max_user_instances __read_mostly; +int inotify_max_user_watches __read_mostly; +int inotify_max_queued_events __read_mostly; /* * 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_dev->mutex (protects inotify_device and watches->d_list) */ /* @@ -79,12 +78,12 @@ int inotify_max_queued_events; /* * struct inotify_device - 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 idr idr; /* idr mapping wd -> watch */ - struct semaphore sem; /* protects this bad boy */ + struct mutex mutex; /* protects this bad boy */ struct list_head events; /* list of queued events */ struct list_head watches; /* list of watches */ atomic_t count; /* reference count */ @@ -101,7 +100,7 @@ struct inotify_device { * 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. + * Protected by dev->mutex of the device in which we are queued. */ struct inotify_kernel_event { struct inotify_event event; /* the user-space event */ @@ -112,8 +111,8 @@ struct inotify_kernel_event { /* * 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. + * d_list is protected by dev->mutex of the associated watch->dev. + * i_list and mask are protected by inode->inotify_mutex of the associated inode. * dev, inode, and wd are never written to once the watch is created. */ struct inotify_watch { @@ -261,7 +260,7 @@ static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie, /* * inotify_dev_get_event - return the next event in the given dev's queue * - * Caller must hold dev->sem. + * Caller must hold dev->mutex. */ static inline struct inotify_kernel_event * inotify_dev_get_event(struct inotify_device *dev) @@ -272,7 +271,7 @@ inotify_dev_get_event(struct inotify_device *dev) /* * inotify_dev_queue_event - add a new event to the given device * - * Caller must hold dev->sem. Can sleep (calls kernel_event()). + * Caller must hold dev->mutex. Can sleep (calls kernel_event()). */ static void inotify_dev_queue_event(struct inotify_device *dev, struct inotify_watch *watch, u32 mask, @@ -315,7 +314,7 @@ static void inotify_dev_queue_event(struct inotify_device *dev, /* * remove_kevent - cleans up and ultimately frees the given kevent * - * Caller must hold dev->sem. + * Caller must hold dev->mutex. */ static void remove_kevent(struct inotify_device *dev, struct inotify_kernel_event *kevent) @@ -332,7 +331,7 @@ static void remove_kevent(struct inotify_device *dev, /* * inotify_dev_event_dequeue - destroy an event on the given device * - * Caller must hold dev->sem. + * Caller must hold dev->mutex. */ static void inotify_dev_event_dequeue(struct inotify_device *dev) { @@ -346,7 +345,7 @@ static void inotify_dev_event_dequeue(struct inotify_device *dev) /* * inotify_dev_get_wd - returns the next WD for use by the given dev * - * Callers must hold dev->sem. This function can sleep. + * Callers must hold dev->mutex. This function can sleep. */ static int inotify_dev_get_wd(struct inotify_device *dev, struct inotify_watch *watch) @@ -380,10 +379,52 @@ static int find_inode(const char __user *dirname, struct nameidata *nd, return error; } +/* + * 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); +} + +/* + * Get child dentry flag into synch with parent inode. + * Flag should always be clear for negative dentrys. + */ +static void set_dentry_child_flags(struct inode *inode, int watched) +{ + struct dentry *alias; + + spin_lock(&dcache_lock); + list_for_each_entry(alias, &inode->i_dentry, d_alias) { + struct dentry *child; + + 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); + } + } + spin_unlock(&dcache_lock); +} + /* * create_watch - creates a watch on the given device. * - * Callers must hold dev->sem. Calls inotify_dev_get_wd() so may sleep. + * Callers must hold dev->mutex. 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, @@ -426,7 +467,6 @@ static struct inotify_watch *create_watch(struct inotify_device *dev, get_inotify_watch(watch); atomic_inc(&dev->user->inotify_watches); - atomic_inc(&inotify_watches); return watch; } @@ -434,7 +474,7 @@ static struct inotify_watch *create_watch(struct inotify_device *dev, /* * inotify_find_dev - find the watch associated with the given inode and dev * - * 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) @@ -458,8 +498,10 @@ static void remove_watch_no_event(struct inotify_watch *watch, list_del(&watch->i_list); list_del(&watch->d_list); + if (!inotify_inode_watched(watch->inode)) + set_dentry_child_flags(watch->inode, 0); + atomic_dec(&dev->user->inotify_watches); - atomic_dec(&inotify_watches); idr_remove(&dev->idr, watch->wd); put_inotify_watch(watch); } @@ -469,7 +511,7 @@ static void remove_watch_no_event(struct inotify_watch *watch, * 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 + * Callers must hold both inode->inotify_mutex and dev->mutex. 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 @@ -481,16 +523,39 @@ static void remove_watch(struct inotify_watch *watch,struct inotify_device *dev) remove_watch_no_event(watch, dev); } +/* Kernel API */ + /* - * 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 @@ -507,21 +572,21 @@ void inotify_inode_queue_event(struct inode *inode, u32 mask, u32 cookie, 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); + mutex_lock(&dev->mutex); inotify_dev_queue_event(dev, watch, mask, cookie, name); if (watch_mask & IN_ONESHOT) remove_watch_no_event(watch, dev); - up(&dev->sem); + mutex_unlock(&dev->mutex); put_inotify_watch(watch); } } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); } EXPORT_SYMBOL_GPL(inotify_inode_queue_event); @@ -538,7 +603,7 @@ 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); @@ -569,7 +634,7 @@ 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) @@ -618,7 +683,7 @@ 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 +691,16 @@ 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); + mutex_lock(&dev->mutex); inotify_dev_queue_event(dev, watch, IN_UNMOUNT,0,NULL); remove_watch(watch, dev); - up(&dev->sem); + mutex_unlock(&dev->mutex); } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); iput(inode); spin_lock(&inode_lock); @@ -651,14 +716,14 @@ 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); + mutex_lock(&dev->mutex); remove_watch(watch, dev); - up(&dev->sem); + mutex_unlock(&dev->mutex); } - up(&inode->inotify_sem); + mutex_unlock(&inode->inotify_mutex); } EXPORT_SYMBOL_GPL(inotify_inode_is_dead); @@ -670,10 +735,10 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait) int ret = 0; poll_wait(file, &dev->wq, wait); - down(&dev->sem); + mutex_lock(&dev->mutex); if (!list_empty(&dev->events)) ret = POLLIN | POLLRDNORM; - up(&dev->sem); + mutex_unlock(&dev->mutex); return ret; } @@ -695,9 +760,9 @@ static ssize_t inotify_read(struct file *file, char __user *buf, prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); - down(&dev->sem); + mutex_lock(&dev->mutex); events = !list_empty(&dev->events); - up(&dev->sem); + mutex_unlock(&dev->mutex); if (events) { ret = 0; break; @@ -720,7 +785,7 @@ static ssize_t inotify_read(struct file *file, char __user *buf, if (ret) return ret; - down(&dev->sem); + mutex_lock(&dev->mutex); while (1) { struct inotify_kernel_event *kevent; @@ -750,7 +815,7 @@ static ssize_t inotify_read(struct file *file, char __user *buf, remove_kevent(dev, kevent); } - up(&dev->sem); + mutex_unlock(&dev->mutex); return ret; } @@ -763,37 +828,41 @@ static int inotify_release(struct inode *ignored, struct file *file) * 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. + * hold inode->inotify_mutex before dev->mutex. The following works. */ while (1) { struct inotify_watch *watch; struct list_head *watches; struct inode *inode; - down(&dev->sem); + mutex_lock(&dev->mutex); watches = &dev->watches; if (list_empty(watches)) { - up(&dev->sem); + mutex_unlock(&dev->mutex); break; } watch = list_entry(watches->next, struct inotify_watch, d_list); get_inotify_watch(watch); - up(&dev->sem); + mutex_unlock(&dev->mutex); inode = watch->inode; - down(&inode->inotify_sem); - down(&dev->sem); - remove_watch_no_event(watch, dev); - up(&dev->sem); - up(&inode->inotify_sem); + mutex_lock(&inode->inotify_mutex); + mutex_lock(&dev->mutex); + + /* make sure we didn't race with another list removal */ + if (likely(idr_find(&dev->idr, watch->wd))) + remove_watch_no_event(watch, dev); + + mutex_unlock(&dev->mutex); + mutex_unlock(&inode->inotify_mutex); put_inotify_watch(watch); } /* destroy all of the events on this device */ - down(&dev->sem); + mutex_lock(&dev->mutex); while (!list_empty(&dev->events)) inotify_dev_event_dequeue(dev); - up(&dev->sem); + mutex_unlock(&dev->mutex); /* free this device: the put matching the get in inotify_init() */ put_inotify_dev(dev); @@ -811,26 +880,25 @@ static int inotify_ignore(struct inotify_device *dev, s32 wd) struct inotify_watch *watch; struct inode *inode; - down(&dev->sem); + mutex_lock(&dev->mutex); watch = idr_find(&dev->idr, wd); if (unlikely(!watch)) { - up(&dev->sem); + mutex_unlock(&dev->mutex); return -EINVAL; } get_inotify_watch(watch); inode = watch->inode; - up(&dev->sem); + mutex_unlock(&dev->mutex); - down(&inode->inotify_sem); - down(&dev->sem); + mutex_lock(&inode->inotify_mutex); + mutex_lock(&dev->mutex); /* make sure that we did not race */ - watch = idr_find(&dev->idr, wd); - if (likely(watch)) + if (likely(idr_find(&dev->idr, wd) == watch)) remove_watch(watch, dev); - up(&dev->sem); - up(&inode->inotify_sem); + mutex_unlock(&dev->mutex); + mutex_unlock(&inode->inotify_mutex); put_inotify_watch(watch); return 0; @@ -855,7 +923,7 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, return ret; } -static struct file_operations inotify_fops = { +static const struct file_operations inotify_fops = { .poll = inotify_poll, .read = inotify_read, .release = inotify_release, @@ -905,7 +973,7 @@ asmlinkage long sys_inotify_init(void) INIT_LIST_HEAD(&dev->events); INIT_LIST_HEAD(&dev->watches); init_waitqueue_head(&dev->wq); - sema_init(&dev->sem, 1); + mutex_init(&dev->mutex); dev->event_count = 0; dev->queue_size = 0; dev->max_events = inotify_max_queued_events; @@ -960,8 +1028,8 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) inode = nd.dentry->d_inode; dev = filp->private_data; - down(&inode->inotify_sem); - down(&dev->sem); + mutex_lock(&inode->inotify_mutex); + mutex_lock(&dev->mutex); if (mask & IN_MASK_ADD) mask_add = 1; @@ -993,13 +1061,16 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) 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); list_add(&watch->i_list, &inode->inotify_watches); ret = watch->wd; out: - up(&dev->sem); - up(&inode->inotify_sem); + mutex_unlock(&dev->mutex); + mutex_unlock(&inode->inotify_mutex); path_release(&nd); fput_and_out: fput_light(filp, fput_needed); @@ -1065,7 +1136,6 @@ static int __init inotify_setup(void) 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),