diff options
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/Kconfig | 1 | ||||
| -rw-r--r-- | fs/notify/Makefile | 4 | ||||
| -rw-r--r-- | fs/notify/dnotify/dnotify.c | 213 | ||||
| -rw-r--r-- | fs/notify/fanotify/Kconfig | 26 | ||||
| -rw-r--r-- | fs/notify/fanotify/Makefile | 1 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 212 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 760 | ||||
| -rw-r--r-- | fs/notify/fsnotify.c | 201 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 27 | ||||
| -rw-r--r-- | fs/notify/group.c | 182 | ||||
| -rw-r--r-- | fs/notify/inode_mark.c | 337 | ||||
| -rw-r--r-- | fs/notify/inotify/Kconfig | 15 | ||||
| -rw-r--r-- | fs/notify/inotify/Makefile | 1 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.c | 873 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify.h | 7 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_fsnotify.c | 151 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 369 | ||||
| -rw-r--r-- | fs/notify/mark.c | 371 | ||||
| -rw-r--r-- | fs/notify/notification.c | 209 | ||||
| -rw-r--r-- | fs/notify/vfsmount_mark.c | 187 |
20 files changed, 2424 insertions, 1723 deletions
diff --git a/fs/notify/Kconfig b/fs/notify/Kconfig index dffbb0911d02..22c629eedd82 100644 --- a/fs/notify/Kconfig +++ b/fs/notify/Kconfig @@ -3,3 +3,4 @@ config FSNOTIFY source "fs/notify/dnotify/Kconfig" source "fs/notify/inotify/Kconfig" +source "fs/notify/fanotify/Kconfig" diff --git a/fs/notify/Makefile b/fs/notify/Makefile index 0922cc826c46..ae5f33a6d868 100644 --- a/fs/notify/Makefile +++ b/fs/notify/Makefile @@ -1,4 +1,6 @@ -obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o +obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o \ + mark.o vfsmount_mark.o obj-y += dnotify/ obj-y += inotify/ +obj-y += fanotify/ diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 7e54e52964dd..3344bdd5506e 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -29,17 +29,17 @@ int dir_notify_enable __read_mostly = 1; static struct kmem_cache *dnotify_struct_cache __read_mostly; -static struct kmem_cache *dnotify_mark_entry_cache __read_mostly; +static struct kmem_cache *dnotify_mark_cache __read_mostly; static struct fsnotify_group *dnotify_group __read_mostly; static DEFINE_MUTEX(dnotify_mark_mutex); /* - * dnotify will attach one of these to each inode (i_fsnotify_mark_entries) which + * dnotify will attach one of these to each inode (i_fsnotify_marks) which * is being watched by dnotify. If multiple userspace applications are watching * the same directory with dnotify their information is chained in dn */ -struct dnotify_mark_entry { - struct fsnotify_mark_entry fsn_entry; +struct dnotify_mark { + struct fsnotify_mark fsn_mark; struct dnotify_struct *dn; }; @@ -51,27 +51,27 @@ struct dnotify_mark_entry { * it calls the fsnotify function so it can update the set of all events relevant * to this inode. */ -static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) +static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark) { __u32 new_mask, old_mask; struct dnotify_struct *dn; - struct dnotify_mark_entry *dnentry = container_of(entry, - struct dnotify_mark_entry, - fsn_entry); + struct dnotify_mark *dn_mark = container_of(fsn_mark, + struct dnotify_mark, + fsn_mark); - assert_spin_locked(&entry->lock); + assert_spin_locked(&fsn_mark->lock); - old_mask = entry->mask; + old_mask = fsn_mark->mask; new_mask = 0; - for (dn = dnentry->dn; dn != NULL; dn = dn->dn_next) + for (dn = dn_mark->dn; dn != NULL; dn = dn->dn_next) new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT); - entry->mask = new_mask; + fsnotify_set_mark_mask_locked(fsn_mark, new_mask); if (old_mask == new_mask) return; - if (entry->inode) - fsnotify_recalc_inode_mask(entry->inode); + if (fsn_mark->i.inode) + fsnotify_recalc_inode_mask(fsn_mark->i.inode); } /* @@ -83,29 +83,25 @@ static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) * events. */ static int dnotify_handle_event(struct fsnotify_group *group, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, struct fsnotify_event *event) { - struct fsnotify_mark_entry *entry = NULL; - struct dnotify_mark_entry *dnentry; + struct dnotify_mark *dn_mark; struct inode *to_tell; struct dnotify_struct *dn; struct dnotify_struct **prev; struct fown_struct *fown; __u32 test_mask = event->mask & ~FS_EVENT_ON_CHILD; - to_tell = event->to_tell; + BUG_ON(vfsmount_mark); - spin_lock(&to_tell->i_lock); - entry = fsnotify_find_mark_entry(group, to_tell); - spin_unlock(&to_tell->i_lock); + to_tell = event->to_tell; - /* unlikely since we alreay passed dnotify_should_send_event() */ - if (unlikely(!entry)) - return 0; - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + dn_mark = container_of(inode_mark, struct dnotify_mark, fsn_mark); - spin_lock(&entry->lock); - prev = &dnentry->dn; + spin_lock(&inode_mark->lock); + prev = &dn_mark->dn; while ((dn = *prev) != NULL) { if ((dn->dn_mask & test_mask) == 0) { prev = &dn->dn_next; @@ -118,12 +114,11 @@ static int dnotify_handle_event(struct fsnotify_group *group, else { *prev = dn->dn_next; kmem_cache_free(dnotify_struct_cache, dn); - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(inode_mark); } } - spin_unlock(&entry->lock); - fsnotify_put_mark(entry); + spin_unlock(&inode_mark->lock); return 0; } @@ -133,44 +128,27 @@ static int dnotify_handle_event(struct fsnotify_group *group, * userspace notification for that pair. */ static bool dnotify_should_send_event(struct fsnotify_group *group, - struct inode *inode, __u32 mask) + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + __u32 mask, void *data, int data_type) { - struct fsnotify_mark_entry *entry; - bool send; - - /* !dir_notify_enable should never get here, don't waste time checking - if (!dir_notify_enable) - return 0; */ - /* not a dir, dnotify doesn't care */ if (!S_ISDIR(inode->i_mode)) return false; - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); - - /* no mark means no dnotify watch */ - if (!entry) - return false; - - mask = (mask & ~FS_EVENT_ON_CHILD); - send = (mask & entry->mask); - - fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */ - - return send; + return true; } -static void dnotify_free_mark(struct fsnotify_mark_entry *entry) +static void dnotify_free_mark(struct fsnotify_mark *fsn_mark) { - struct dnotify_mark_entry *dnentry = container_of(entry, - struct dnotify_mark_entry, - fsn_entry); + struct dnotify_mark *dn_mark = container_of(fsn_mark, + struct dnotify_mark, + fsn_mark); - BUG_ON(dnentry->dn); + BUG_ON(dn_mark->dn); - kmem_cache_free(dnotify_mark_entry_cache, dnentry); + kmem_cache_free(dnotify_mark_cache, dn_mark); } static struct fsnotify_ops dnotify_fsnotify_ops = { @@ -183,15 +161,15 @@ static struct fsnotify_ops dnotify_fsnotify_ops = { /* * Called every time a file is closed. Looks first for a dnotify mark on the - * inode. If one is found run all of the ->dn entries attached to that + * inode. If one is found run all of the ->dn structures attached to that * mark for one relevant to this process closing the file and remove that * dnotify_struct. If that was the last dnotify_struct also remove the - * fsnotify_mark_entry. + * fsnotify_mark. */ void dnotify_flush(struct file *filp, fl_owner_t id) { - struct fsnotify_mark_entry *entry; - struct dnotify_mark_entry *dnentry; + struct fsnotify_mark *fsn_mark; + struct dnotify_mark *dn_mark; struct dnotify_struct *dn; struct dnotify_struct **prev; struct inode *inode; @@ -200,38 +178,34 @@ void dnotify_flush(struct file *filp, fl_owner_t id) if (!S_ISDIR(inode->i_mode)) return; - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(dnotify_group, inode); - spin_unlock(&inode->i_lock); - if (!entry) + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); + if (!fsn_mark) return; - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); + dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); mutex_lock(&dnotify_mark_mutex); - spin_lock(&entry->lock); - prev = &dnentry->dn; + spin_lock(&fsn_mark->lock); + prev = &dn_mark->dn; while ((dn = *prev) != NULL) { if ((dn->dn_owner == id) && (dn->dn_filp == filp)) { *prev = dn->dn_next; kmem_cache_free(dnotify_struct_cache, dn); - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(fsn_mark); break; } prev = &dn->dn_next; } - spin_unlock(&entry->lock); + spin_unlock(&fsn_mark->lock); /* nothing else could have found us thanks to the dnotify_mark_mutex */ - if (dnentry->dn == NULL) - fsnotify_destroy_mark_by_entry(entry); - - fsnotify_recalc_group_mask(dnotify_group); + if (dn_mark->dn == NULL) + fsnotify_destroy_mark(fsn_mark); mutex_unlock(&dnotify_mark_mutex); - fsnotify_put_mark(entry); + fsnotify_put_mark(fsn_mark); } /* this conversion is done only at watch creation */ @@ -259,16 +233,16 @@ static __u32 convert_arg(unsigned long arg) /* * If multiple processes watch the same inode with dnotify there is only one - * dnotify mark in inode->i_fsnotify_mark_entries but we chain a dnotify_struct + * dnotify mark in inode->i_fsnotify_marks but we chain a dnotify_struct * onto that mark. This function either attaches the new dnotify_struct onto * that list, or it |= the mask onto an existing dnofiy_struct. */ -static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnentry, +static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark *dn_mark, fl_owner_t id, int fd, struct file *filp, __u32 mask) { struct dnotify_struct *odn; - odn = dnentry->dn; + odn = dn_mark->dn; while (odn != NULL) { /* adding more events to existing dnofiy_struct? */ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { @@ -283,8 +257,8 @@ static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnent dn->dn_fd = fd; dn->dn_filp = filp; dn->dn_owner = id; - dn->dn_next = dnentry->dn; - dnentry->dn = dn; + dn->dn_next = dn_mark->dn; + dn_mark->dn = dn; return 0; } @@ -296,8 +270,8 @@ static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnent */ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) { - struct dnotify_mark_entry *new_dnentry, *dnentry; - struct fsnotify_mark_entry *new_entry, *entry; + struct dnotify_mark *new_dn_mark, *dn_mark; + struct fsnotify_mark *new_fsn_mark, *fsn_mark; struct dnotify_struct *dn; struct inode *inode; fl_owner_t id = current->files; @@ -306,7 +280,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) __u32 mask; /* we use these to tell if we need to kfree */ - new_entry = NULL; + new_fsn_mark = NULL; dn = NULL; if (!dir_notify_enable) { @@ -336,8 +310,8 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) } /* new fsnotify mark, we expect most fcntl calls to add a new mark */ - new_dnentry = kmem_cache_alloc(dnotify_mark_entry_cache, GFP_KERNEL); - if (!new_dnentry) { + new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL); + if (!new_dn_mark) { error = -ENOMEM; goto out_err; } @@ -345,29 +319,27 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */ mask = convert_arg(arg); - /* set up the new_entry and new_dnentry */ - new_entry = &new_dnentry->fsn_entry; - fsnotify_init_mark(new_entry, dnotify_free_mark); - new_entry->mask = mask; - new_dnentry->dn = NULL; + /* set up the new_fsn_mark and new_dn_mark */ + new_fsn_mark = &new_dn_mark->fsn_mark; + fsnotify_init_mark(new_fsn_mark, dnotify_free_mark); + new_fsn_mark->mask = mask; + new_dn_mark->dn = NULL; /* this is needed to prevent the fcntl/close race described below */ mutex_lock(&dnotify_mark_mutex); - /* add the new_entry or find an old one. */ - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(dnotify_group, inode); - spin_unlock(&inode->i_lock); - if (entry) { - dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry); - spin_lock(&entry->lock); + /* add the new_fsn_mark or find an old one. */ + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); + if (fsn_mark) { + dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); + spin_lock(&fsn_mark->lock); } else { - fsnotify_add_mark(new_entry, dnotify_group, inode); - spin_lock(&new_entry->lock); - entry = new_entry; - dnentry = new_dnentry; - /* we used new_entry, so don't free it */ - new_entry = NULL; + fsnotify_add_mark(new_fsn_mark, dnotify_group, inode, NULL, 0); + spin_lock(&new_fsn_mark->lock); + fsn_mark = new_fsn_mark; + dn_mark = new_dn_mark; + /* we used new_fsn_mark, so don't free it */ + new_fsn_mark = NULL; } rcu_read_lock(); @@ -376,17 +348,17 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) /* if (f != filp) means that we lost a race and another task/thread * actually closed the fd we are still playing with before we grabbed - * the dnotify_mark_mutex and entry->lock. Since closing the fd is the - * only time we clean up the mark entries we need to get our mark off + * the dnotify_mark_mutex and fsn_mark->lock. Since closing the fd is the + * only time we clean up the marks we need to get our mark off * the list. */ if (f != filp) { /* if we added ourselves, shoot ourselves, it's possible that - * the flush actually did shoot this entry. That's fine too + * the flush actually did shoot this fsn_mark. That's fine too * since multiple calls to destroy_mark is perfectly safe, if - * we found a dnentry already attached to the inode, just sod + * we found a dn_mark already attached to the inode, just sod * off silently as the flush at close time dealt with it. */ - if (dnentry == new_dnentry) + if (dn_mark == new_dn_mark) destroy = 1; goto out; } @@ -394,13 +366,13 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); if (error) { /* if we added, we must shoot */ - if (dnentry == new_dnentry) + if (dn_mark == new_dn_mark) destroy = 1; goto out; } - error = attach_dn(dn, dnentry, id, fd, filp, mask); - /* !error means that we attached the dn to the dnentry, so don't free it */ + error = attach_dn(dn, dn_mark, id, fd, filp, mask); + /* !error means that we attached the dn to the dn_mark, so don't free it */ if (!error) dn = NULL; /* -EEXIST means that we didn't add this new dn and used an old one. @@ -408,20 +380,18 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) else if (error == -EEXIST) error = 0; - dnotify_recalc_inode_mask(entry); + dnotify_recalc_inode_mask(fsn_mark); out: - spin_unlock(&entry->lock); + spin_unlock(&fsn_mark->lock); if (destroy) - fsnotify_destroy_mark_by_entry(entry); - - fsnotify_recalc_group_mask(dnotify_group); + fsnotify_destroy_mark(fsn_mark); mutex_unlock(&dnotify_mark_mutex); - fsnotify_put_mark(entry); + fsnotify_put_mark(fsn_mark); out_err: - if (new_entry) - fsnotify_put_mark(new_entry); + if (new_fsn_mark) + fsnotify_put_mark(new_fsn_mark); if (dn) kmem_cache_free(dnotify_struct_cache, dn); return error; @@ -430,10 +400,9 @@ out_err: static int __init dnotify_init(void) { dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC); - dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC); + dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC); - dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM, - 0, &dnotify_fsnotify_ops); + dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops); if (IS_ERR(dnotify_group)) panic("unable to allocate fsnotify group for dnotify\n"); return 0; diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig new file mode 100644 index 000000000000..3ac36b7bf6b9 --- /dev/null +++ b/fs/notify/fanotify/Kconfig @@ -0,0 +1,26 @@ +config FANOTIFY + bool "Filesystem wide access notification" + select FSNOTIFY + select ANON_INODES + default n + ---help--- + Say Y here to enable fanotify suport. fanotify is a file access + notification system which differs from inotify in that it sends + and open file descriptor to the userspace listener along with + the event. + + If unsure, say Y. + +config FANOTIFY_ACCESS_PERMISSIONS + bool "fanotify permissions checking" + depends on FANOTIFY + depends on SECURITY + default n + ---help--- + Say Y here is you want fanotify listeners to be able to make permissions + decisions concerning filesystem events. This is used by some fanotify + listeners which need to scan files before allowing the system access to + use those files. This is used by some anti-malware vendors and by some + hierarchical storage managent systems. + + If unsure, say N. diff --git a/fs/notify/fanotify/Makefile b/fs/notify/fanotify/Makefile new file mode 100644 index 000000000000..0999213e7e6e --- /dev/null +++ b/fs/notify/fanotify/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_FANOTIFY) += fanotify.o fanotify_user.o diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c new file mode 100644 index 000000000000..756566fe8449 --- /dev/null +++ b/fs/notify/fanotify/fanotify.c @@ -0,0 +1,212 @@ +#include <linux/fanotify.h> +#include <linux/fdtable.h> +#include <linux/fsnotify_backend.h> +#include <linux/init.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> /* UINT_MAX */ +#include <linux/mount.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/wait.h> + +static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new) +{ + pr_debug("%s: old=%p new=%p\n", __func__, old, new); + + if (old->to_tell == new->to_tell && + old->data_type == new->data_type && + old->tgid == new->tgid) { + switch (old->data_type) { + case (FSNOTIFY_EVENT_PATH): + if ((old->path.mnt == new->path.mnt) && + (old->path.dentry == new->path.dentry)) + return true; + case (FSNOTIFY_EVENT_NONE): + return true; + default: + BUG(); + }; + } + return false; +} + +/* and the list better be locked by something too! */ +static struct fsnotify_event *fanotify_merge(struct list_head *list, + struct fsnotify_event *event) +{ + struct fsnotify_event_holder *test_holder; + struct fsnotify_event *test_event = NULL; + struct fsnotify_event *new_event; + + pr_debug("%s: list=%p event=%p\n", __func__, list, event); + + + list_for_each_entry_reverse(test_holder, list, event_list) { + if (should_merge(test_holder->event, event)) { + test_event = test_holder->event; + break; + } + } + + if (!test_event) + return NULL; + + fsnotify_get_event(test_event); + + /* if they are exactly the same we are done */ + if (test_event->mask == event->mask) + return test_event; + + /* + * if the refcnt == 2 this is the only queue + * for this event and so we can update the mask + * in place. + */ + if (atomic_read(&test_event->refcnt) == 2) { + test_event->mask |= event->mask; + return test_event; + } + + new_event = fsnotify_clone_event(test_event); + + /* done with test_event */ + fsnotify_put_event(test_event); + + /* couldn't allocate memory, merge was not possible */ + if (unlikely(!new_event)) + return ERR_PTR(-ENOMEM); + + /* build new event and replace it on the list */ + new_event->mask = (test_event->mask | event->mask); + fsnotify_replace_event(test_holder, new_event); + + /* we hold a reference on new_event from clone_event */ + return new_event; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static int fanotify_get_response_from_access(struct fsnotify_group *group, + struct fsnotify_event *event) +{ + int ret; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + wait_event(group->fanotify_data.access_waitq, event->response); + + /* userspace responded, convert to something usable */ + spin_lock(&event->lock); + switch (event->response) { + case FAN_ALLOW: + ret = 0; + break; + case FAN_DENY: + default: + ret = -EPERM; + } + event->response = 0; + spin_unlock(&event->lock); + + pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, + group, event, ret); + + return ret; +} +#endif + +static int fanotify_handle_event(struct fsnotify_group *group, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *fanotify_mark, + struct fsnotify_event *event) +{ + int ret = 0; + struct fsnotify_event *notify_event = NULL; + + BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(FAN_OPEN != FS_OPEN); + BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); + BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); + BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); + BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + notify_event = fsnotify_add_notify_event(group, event, NULL, fanotify_merge); + if (IS_ERR(notify_event)) + return PTR_ERR(notify_event); + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (event->mask & FAN_ALL_PERM_EVENTS) { + /* if we merged we need to wait on the new event */ + if (notify_event) + event = notify_event; + ret = fanotify_get_response_from_access(group, event); + } +#endif + + if (notify_event) + fsnotify_put_event(notify_event); + + return ret; +} + +static bool fanotify_should_send_event(struct fsnotify_group *group, + struct inode *to_tell, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmnt_mark, + __u32 event_mask, void *data, int data_type) +{ + __u32 marks_mask, marks_ignored_mask; + + pr_debug("%s: group=%p to_tell=%p inode_mark=%p vfsmnt_mark=%p " + "mask=%x data=%p data_type=%d\n", __func__, group, to_tell, + inode_mark, vfsmnt_mark, event_mask, data, data_type); + + pr_debug("%s: group=%p vfsmount_mark=%p inode_mark=%p mask=%x\n", + __func__, group, vfsmnt_mark, inode_mark, event_mask); + + /* sorry, fanotify only gives a damn about files and dirs */ + if (!S_ISREG(to_tell->i_mode) && + !S_ISDIR(to_tell->i_mode)) + return false; + + /* if we don't have enough info to send an event to userspace say no */ + if (data_type != FSNOTIFY_EVENT_PATH) + return false; + + if (inode_mark && vfsmnt_mark) { + marks_mask = (vfsmnt_mark->mask | inode_mark->mask); + marks_ignored_mask = (vfsmnt_mark->ignored_mask | inode_mark->ignored_mask); + } else if (inode_mark) { + /* + * if the event is for a child and this inode doesn't care about + * events on the child, don't send it! + */ + if ((event_mask & FS_EVENT_ON_CHILD) && + !(inode_mark->mask & FS_EVENT_ON_CHILD)) + return false; + marks_mask = inode_mark->mask; + marks_ignored_mask = inode_mark->ignored_mask; + } else if (vfsmnt_mark) { + marks_mask = vfsmnt_mark->mask; + marks_ignored_mask = vfsmnt_mark->ignored_mask; + } else { + BUG(); + } + + if (event_mask & marks_mask & ~marks_ignored_mask) + return true; + + return false; +} + +const struct fsnotify_ops fanotify_fsnotify_ops = { + .handle_event = fanotify_handle_event, + .should_send_event = fanotify_should_send_event, + .free_group_priv = NULL, + .free_event_priv = NULL, + .freeing_mark = NULL, +}; diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c new file mode 100644 index 000000000000..032b837fcd11 --- /dev/null +++ b/fs/notify/fanotify/fanotify_user.c @@ -0,0 +1,760 @@ +#include <linux/fanotify.h> +#include <linux/fcntl.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/anon_inodes.h> +#include <linux/fsnotify_backend.h> +#include <linux/init.h> +#include <linux/mount.h> +#include <linux/namei.h> +#include <linux/poll.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#include <asm/ioctls.h> + +extern const struct fsnotify_ops fanotify_fsnotify_ops; + +static struct kmem_cache *fanotify_mark_cache __read_mostly; +static struct kmem_cache *fanotify_response_event_cache __read_mostly; + +struct fanotify_response_event { + struct list_head list; + __s32 fd; + struct fsnotify_event *event; +}; + +/* + * Get an fsnotify notification event if one exists and is small + * enough to fit in "count". Return an error pointer if the count + * is not large enough. + * + * Called with the group->notification_mutex held. + */ +static struct fsnotify_event *get_one_event(struct fsnotify_group *group, + size_t count) +{ + BUG_ON(!mutex_is_locked(&group->notification_mutex)); + + pr_debug("%s: group=%p count=%zd\n", __func__, group, count); + + if (fsnotify_notify_queue_is_empty(group)) + return NULL; + + if (FAN_EVENT_METADATA_LEN > count) + return ERR_PTR(-EINVAL); + + /* held the notification_mutex the whole time, so this is the + * same event we peeked above */ + return fsnotify_remove_notify_event(group); +} + +static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event) +{ + int client_fd; + struct dentry *dentry; + struct vfsmount *mnt; + struct file *new_file; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + client_fd = get_unused_fd(); + if (client_fd < 0) + return client_fd; + + if (event->data_type != FSNOTIFY_EVENT_PATH) { + WARN_ON(1); + put_unused_fd(client_fd); + return -EINVAL; + } + + /* + * we need a new file handle for the userspace program so it can read even if it was + * originally opened O_WRONLY. + */ + dentry = dget(event->path.dentry); + mnt = mntget(event->path.mnt); + /* it's possible this event was an overflow event. in that case dentry and mnt + * are NULL; That's fine, just don't call dentry open */ + if (dentry && mnt) + new_file = dentry_open(dentry, mnt, + group->fanotify_data.f_flags | FMODE_NONOTIFY, + current_cred()); + else + new_file = ERR_PTR(-EOVERFLOW); + if (IS_ERR(new_file)) { + /* + * we still send an event even if we can't open the file. this + * can happen when say tasks are gone and we try to open their + * /proc files or we try to open a WRONLY file like in sysfs + * we just send the errno to userspace since there isn't much + * else we can do. + */ + put_unused_fd(client_fd); + client_fd = PTR_ERR(new_file); + } else { + fd_install(client_fd, new_file); + } + + return client_fd; +} + +static ssize_t fill_event_metadata(struct fsnotify_group *group, + struct fanotify_event_metadata *metadata, + struct fsnotify_event *event) +{ + pr_debug("%s: group=%p metadata=%p event=%p\n", __func__, + group, metadata, event); + + metadata->event_len = FAN_EVENT_METADATA_LEN; + metadata->vers = FANOTIFY_METADATA_VERSION; + metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS; + metadata->pid = pid_vnr(event->tgid); + metadata->fd = create_fd(group, event); + + return metadata->fd; +} + +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, + __s32 fd) +{ + struct fanotify_response_event *re, *return_re = NULL; + + mutex_lock(&group->fanotify_data.access_mutex); + list_for_each_entry(re, &group->fanotify_data.access_list, list) { + if (re->fd != fd) + continue; + + list_del_init(&re->list); + return_re = re; + break; + } + mutex_unlock(&group->fanotify_data.access_mutex); + + pr_debug("%s: found return_re=%p\n", __func__, return_re); + + return return_re; +} + +static int process_access_response(struct fsnotify_group *group, + struct fanotify_response *response_struct) +{ + struct fanotify_response_event *re; + __s32 fd = response_struct->fd; + __u32 response = response_struct->response; + + pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, + fd, response); + /* + * make sure the response is valid, if invalid we do nothing and either + * userspace can send a valid responce or we will clean it up after the + * timeout + */ + switch (response) { + case FAN_ALLOW: + case FAN_DENY: + break; + default: + return -EINVAL; + } + + if (fd < 0) + return -EINVAL; + + re = dequeue_re(group, fd); + if (!re) + return -ENOENT; + + re->event->response = response; + + wake_up(&group->fanotify_data.access_waitq); + + kmem_cache_free(fanotify_response_event_cache, re); + + return 0; +} + +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return 0; + + re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); + if (!re) + return -ENOMEM; + + re->event = event; + re->fd = fd; + + mutex_lock(&group->fanotify_data.access_mutex); + list_add_tail(&re->list, &group->fanotify_data.access_list); + mutex_unlock(&group->fanotify_data.access_mutex); + + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return; + + re = dequeue_re(group, fd); + if (!re) + return; + + BUG_ON(re->event != event); + + kmem_cache_free(fanotify_response_event_cache, re); + + return; +} +#else +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return; +} +#endif + +static ssize_t copy_event_to_user(struct fsnotify_group *group, + struct fsnotify_event *event, + char __user *buf) +{ + struct fanotify_event_metadata fanotify_event_metadata; + int fd, ret; + + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + + fd = fill_event_metadata(group, &fanotify_event_metadata, event); + if (fd < 0) + return fd; + + ret = prepare_for_access_response(group, event, fd); + if (ret) + goto out_close_fd; + + ret = -EFAULT; + if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN)) + goto out_kill_access_response; + + return FAN_EVENT_METADATA_LEN; + +out_kill_access_response: + remove_access_response(group, event, fd); +out_close_fd: + sys_close(fd); + return ret; +} + +/* intofiy userspace file descriptor functions */ +static unsigned int fanotify_poll(struct file *file, poll_table *wait) +{ + struct fsnotify_group *group = file->private_data; + int ret = 0; + + poll_wait(file, &group->notification_waitq, wait); + mutex_lock(&group->notification_mutex); + if (!fsnotify_notify_queue_is_empty(group)) + ret = POLLIN | POLLRDNORM; + mutex_unlock(&group->notification_mutex); + + return ret; +} + +static ssize_t fanotify_read(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + struct fsnotify_group *group; + struct fsnotify_event *kevent; + char __user *start; + int ret; + DEFINE_WAIT(wait); + + start = buf; + group = file->private_data; + + pr_debug("%s: group=%p\n", __func__, group); + + while (1) { + prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE); + + mutex_lock(&group->notification_mutex); + kevent = get_one_event(group, count); + mutex_unlock(&group->notification_mutex); + + if (kevent) { + ret = PTR_ERR(kevent); + if (IS_ERR(kevent)) + break; + ret = copy_event_to_user(group, kevent, buf); + fsnotify_put_event(kevent); + if (ret < 0) + break; + buf += ret; + count -= ret; + continue; + } + + ret = -EAGAIN; + if (file->f_flags & O_NONBLOCK) + break; + ret = -EINTR; + if (signal_pending(current)) + break; + + if (start != buf) + break; + + schedule(); + } + + finish_wait(&group->notification_waitq, &wait); + if (start != buf && ret != -EFAULT) + ret = buf - start; + return ret; +} + +static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) +{ +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + struct fanotify_response response = { .fd = -1, .response = -1 }; + struct fsnotify_group *group; + int ret; + + group = file->private_data; + + if (count > sizeof(response)) + count = sizeof(response); + + pr_debug("%s: group=%p count=%zu\n", __func__, group, count); + + if (copy_from_user(&response, buf, count)) + return -EFAULT; + + ret = process_access_response(group, &response); + if (ret < 0) + count = ret; + + return count; +#else + return -EINVAL; +#endif +} + +static int fanotify_release(struct inode *ignored, struct file *file) +{ + struct fsnotify_group *group = file->private_data; + + pr_debug("%s: file=%p group=%p\n", __func__, file, group); + + /* matches the fanotify_init->fsnotify_alloc_group */ + fsnotify_put_group(group); + + return 0; +} + +static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct fsnotify_group *group; + struct fsnotify_event_holder *holder; + void __user *p; + int ret = -ENOTTY; + size_t send_len = 0; + + group = file->private_data; + + p = (void __user *) arg; + + switch (cmd) { + case FIONREAD: + mutex_lock(&group->notification_mutex); + list_for_each_entry(holder, &group->notification_list, event_list) + send_len += FAN_EVENT_METADATA_LEN; + mutex_unlock(&group->notification_mutex); + ret = put_user(send_len, (int __user *) p); + break; + } + + return ret; +} + +static const struct file_operations fanotify_fops = { + .poll = fanotify_poll, + .read = fanotify_read, + .write = fanotify_write, + .fasync = NULL, + .release = fanotify_release, + .unlocked_ioctl = fanotify_ioctl, + .compat_ioctl = fanotify_ioctl, +}; + +static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) +{ + kmem_cache_free(fanotify_mark_cache, fsn_mark); +} + +static int fanotify_find_path(int dfd, const char __user *filename, + struct path *path, unsigned int flags) +{ + int ret; + + pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__, + dfd, filename, flags); + + if (filename == NULL) { + struct file *file; + int fput_needed; + + ret = -EBADF; + file = fget_light(dfd, &fput_needed); + if (!file) + goto out; + + ret = -ENOTDIR; + if ((flags & FAN_MARK_ONLYDIR) && + !(S_ISDIR(file->f_path.dentry->d_inode->i_mode))) { + fput_light(file, fput_needed); + goto out; + } + + *path = file->f_path; + path_get(path); + fput_light(file, fput_needed); + } else { + unsigned int lookup_flags = 0; + + if (!(flags & FAN_MARK_DONT_FOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + if (flags & FAN_MARK_ONLYDIR) + lookup_flags |= LOOKUP_DIRECTORY; + + ret = user_path_at(dfd, filename, lookup_flags, path); + if (ret) + goto out; + } + + /* you can only watch an inode if you have read permissions on it */ + ret = inode_permission(path->dentry->d_inode, MAY_READ); + if (ret) + path_put(path); +out: + return ret; +} + +static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark, + __u32 mask, + unsigned int flags) +{ + __u32 oldmask; + + spin_lock(&fsn_mark->lock); + if (!(flags & FAN_MARK_IGNORED_MASK)) { + oldmask = fsn_mark->mask; + fsnotify_set_mark_mask_locked(fsn_mark, (oldmask & ~mask)); + } else { + oldmask = fsn_mark->ignored_mask; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask & ~mask)); + } + spin_unlock(&fsn_mark->lock); + + if (!(oldmask & ~mask)) + fsnotify_destroy_mark(fsn_mark); + + return mask & oldmask; +} + +static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark = NULL; + __u32 removed; + + fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); + if (!fsn_mark) + return -ENOENT; + + removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); + fsnotify_put_mark(fsn_mark); + if (removed & mnt->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); + + return 0; +} + +static int fanotify_remove_inode_mark(struct fsnotify_group *group, + struct inode *inode, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark = NULL; + __u32 removed; + + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) + return -ENOENT; + + removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags); + /* matches the fsnotify_find_inode_mark() */ + fsnotify_put_mark(fsn_mark); + if (removed & inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); + + return 0; +} + +static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark, + __u32 mask, + unsigned int flags) +{ + __u32 oldmask; + + spin_lock(&fsn_mark->lock); + if (!(flags & FAN_MARK_IGNORED_MASK)) { + oldmask = fsn_mark->mask; + fsnotify_set_mark_mask_locked(fsn_mark, (oldmask | mask)); + } else { + oldmask = fsn_mark->ignored_mask; + fsnotify_set_mark_ignored_mask_locked(fsn_mark, (oldmask | mask)); + if (flags & FAN_MARK_IGNORED_SURV_MODIFY) + fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY; + } + spin_unlock(&fsn_mark->lock); + + return mask & ~oldmask; +} + +static int fanotify_add_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark; + __u32 added; + + fsn_mark = fsnotify_find_vfsmount_mark(group, mnt); + if (!fsn_mark) { + int ret; + + fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); + if (!fsn_mark) + return -ENOMEM; + + fsnotify_init_mark(fsn_mark, fanotify_free_mark); + ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0); + if (ret) { + fanotify_free_mark(fsn_mark); + return ret; + } + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + fsnotify_put_mark(fsn_mark); + if (added & ~mnt->mnt_fsnotify_mask) + fsnotify_recalc_vfsmount_mask(mnt); + + return 0; +} + +static int fanotify_add_inode_mark(struct fsnotify_group *group, + struct inode *inode, __u32 mask, + unsigned int flags) +{ + struct fsnotify_mark *fsn_mark; + __u32 added; + + pr_debug("%s: group=%p inode=%p\n", __func__, group, inode); + + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) { + int ret; + + fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL); + if (!fsn_mark) + return -ENOMEM; + + fsnotify_init_mark(fsn_mark, fanotify_free_mark); + ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0); + if (ret) { + fanotify_free_mark(fsn_mark); + return ret; + } + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); + fsnotify_put_mark(fsn_mark); + if (added & ~inode->i_fsnotify_mask) + fsnotify_recalc_inode_mask(inode); + return 0; +} + +/* fanotify syscalls */ +SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) +{ + struct fsnotify_group *group; + int f_flags, fd; + + pr_debug("%s: flags=%d event_f_flags=%d\n", + __func__, flags, event_f_flags); + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (flags & ~FAN_ALL_INIT_FLAGS) + return -EINVAL; + + f_flags = O_RDWR | FMODE_NONOTIFY; + if (flags & FAN_CLOEXEC) + f_flags |= O_CLOEXEC; + if (flags & FAN_NONBLOCK) + f_flags |= O_NONBLOCK; + + /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ + group = fsnotify_alloc_group(&fanotify_fsnotify_ops); + if (IS_ERR(group)) + return PTR_ERR(group); + + group->fanotify_data.f_flags = event_f_flags; +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + mutex_init(&group->fanotify_data.access_mutex); + init_waitqueue_head(&group->fanotify_data.access_waitq); + INIT_LIST_HEAD(&group->fanotify_data.access_list); +#endif + + fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags); + if (fd < 0) + goto out_put_group; + + return fd; + +out_put_group: + fsnotify_put_group(group); + return fd; +} + +SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, + __u64 mask, int dfd, + const char __user * pathname) +{ + struct inode *inode = NULL; + struct vfsmount *mnt = NULL; + struct fsnotify_group *group; + struct file *filp; + struct path path; + int ret, fput_needed; + + pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n", + __func__, fanotify_fd, flags, dfd, pathname, mask); + + /* we only use the lower 32 bits as of right now. */ + if (mask & ((__u64)0xffffffff << 32)) + return -EINVAL; + + if (flags & ~FAN_ALL_MARK_FLAGS) + return -EINVAL; + switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { + case FAN_MARK_ADD: + case FAN_MARK_REMOVE: + case FAN_MARK_FLUSH: + break; + default: + return -EINVAL; + } +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) +#else + if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) +#endif + return -EINVAL; + + filp = fget_light(fanotify_fd, &fput_needed); + if (unlikely(!filp)) + return -EBADF; + + /* verify that this is indeed an fanotify instance */ + ret = -EINVAL; + if (unlikely(filp->f_op != &fanotify_fops)) + goto fput_and_out; + + ret = fanotify_find_path(dfd, pathname, &path, flags); + if (ret) + goto fput_and_out; + + /* inode held in place by reference to path; group by fget on fd */ + if (!(flags & FAN_MARK_MOUNT)) + inode = path.dentry->d_inode; + else + mnt = path.mnt; + group = filp->private_data; + + /* create/update an inode mark */ + switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) { + case FAN_MARK_ADD: + if (flags & FAN_MARK_MOUNT) + ret = fanotify_add_vfsmount_mark(group, mnt, mask, flags); + else + ret = fanotify_add_inode_mark(group, inode, mask, flags); + break; + case FAN_MARK_REMOVE: + if (flags & FAN_MARK_MOUNT) + ret = fanotify_remove_vfsmount_mark(group, mnt, mask, flags); + else + ret = fanotify_remove_inode_mark(group, inode, mask, flags); + break; + case FAN_MARK_FLUSH: + if (flags & FAN_MARK_MOUNT) + fsnotify_clear_vfsmount_marks_by_group(group); + else + fsnotify_clear_inode_marks_by_group(group); + break; + default: + ret = -EINVAL; + } + + path_put(&path); +fput_and_out: + fput_light(filp, fput_needed); + return ret; +} + +#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS +asmlinkage long SyS_fanotify_mark(long fanotify_fd, long flags, __u64 mask, + long dfd, long pathname) +{ + return SYSC_fanotify_mark((int) fanotify_fd, (unsigned int) flags, + mask, (int) dfd, + (const char __user *) pathname); +} +SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); +#endif + +/* + * fanotify_user_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 fanotify_user_setup(void) +{ + fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); + fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, + SLAB_PANIC); + + return 0; +} +device_initcall(fanotify_user_setup); diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index fcc2f064af83..3970392b2722 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -21,6 +21,7 @@ #include <linux/gfp.h> #include <linux/init.h> #include <linux/module.h> +#include <linux/mount.h> #include <linux/srcu.h> #include <linux/fsnotify_backend.h> @@ -35,6 +36,11 @@ void __fsnotify_inode_delete(struct inode *inode) } EXPORT_SYMBOL_GPL(__fsnotify_inode_delete); +void __fsnotify_vfsmount_delete(struct vfsmount *mnt) +{ + fsnotify_clear_marks_by_mount(mnt); +} + /* * Given an inode, first check if we care what happens to our children. Inotify * and dnotify both tell their parents about events. If we care about any event @@ -78,13 +84,16 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) } /* Notify this dentry's parent about a child's events. */ -void __fsnotify_parent(struct dentry *dentry, __u32 mask) +void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask) { struct dentry *parent; struct inode *p_inode; bool send = false; bool should_update_children = false; + if (!dentry) + dentry = path->dentry; + if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) return; @@ -115,8 +124,12 @@ void __fsnotify_parent(struct dentry *dentry, __u32 mask) * specifies these are events which came from a child. */ mask |= FS_EVENT_ON_CHILD; - fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, - dentry->d_name.name, 0); + if (path) + fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, + dentry->d_name.name, 0); + else + fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, + dentry->d_name.name, 0); dput(parent); } @@ -127,63 +140,181 @@ void __fsnotify_parent(struct dentry *dentry, __u32 mask) } EXPORT_SYMBOL_GPL(__fsnotify_parent); +static int send_to_group(struct inode *to_tell, struct vfsmount *mnt, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + __u32 mask, void *data, + int data_is, u32 cookie, + const unsigned char *file_name, + struct fsnotify_event **event) +{ + struct fsnotify_group *group = inode_mark->group; + __u32 inode_test_mask = (mask & ~FS_EVENT_ON_CHILD); + __u32 vfsmount_test_mask = (mask & ~FS_EVENT_ON_CHILD); + + pr_debug("%s: group=%p to_tell=%p mnt=%p mark=%p mask=%x data=%p" + " data_is=%d cookie=%d event=%p\n", __func__, group, to_tell, + mnt, inode_mark, mask, data, data_is, cookie, *event); + + /* clear ignored on inode modification */ + if (mask & FS_MODIFY) { + if (inode_mark && + !(inode_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + inode_mark->ignored_mask = 0; + if (vfsmount_mark && + !(vfsmount_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + vfsmount_mark->ignored_mask = 0; + } + + /* does the inode mark tell us to do something? */ + if (inode_mark) { + inode_test_mask &= inode_mark->mask; + inode_test_mask &= ~inode_mark->ignored_mask; + } + + /* does the vfsmount_mark tell us to do something? */ + if (vfsmount_mark) { + vfsmount_test_mask &= vfsmount_mark->mask; + vfsmount_test_mask &= ~vfsmount_mark->ignored_mask; + if (inode_mark) + vfsmount_test_mask &= ~inode_mark->ignored_mask; + } + + if (!inode_test_mask && !vfsmount_test_mask) + return 0; + + if (group->ops->should_send_event(group, to_tell, inode_mark, + vfsmount_mark, mask, data, + data_is) == false) + return 0; + + if (!*event) { + *event = fsnotify_create_event(to_tell, mask, data, + data_is, file_name, + cookie, GFP_KERNEL); + if (!*event) + return -ENOMEM; + } + return group->ops->handle_event(group, inode_mark, vfsmount_mark, *event); +} + /* * This is the main call to fsnotify. The VFS calls into hook specific functions * in linux/fsnotify.h. Those functions then in turn call here. Here will call * out to all of the registered fsnotify_group. Those groups can then use the * notification event in whatever means they feel necessary. */ -void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name, u32 cookie) +int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, + const unsigned char *file_name, u32 cookie) { - struct fsnotify_group *group; + struct hlist_node *inode_node, *vfsmount_node; + struct fsnotify_mark *inode_mark = NULL, *vfsmount_mark = NULL; + struct fsnotify_group *inode_group, *vfsmount_group; struct fsnotify_event *event = NULL; - int idx; + struct vfsmount *mnt; + int idx, ret = 0; + bool used_inode = false, used_vfsmount = false; /* global tests shouldn't care about events on child only the specific event */ __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD); - if (list_empty(&fsnotify_groups)) - return; + if (data_is == FSNOTIFY_EVENT_PATH) + mnt = ((struct path *)data)->mnt; + else + mnt = NULL; - if (!(test_mask & fsnotify_mask)) - return; - - if (!(test_mask & to_tell->i_fsnotify_mask)) - return; /* - * SRCU!! the groups list is very very much read only and the path is - * very hot. The VAST majority of events are not going to need to do - * anything other than walk the list so it's crazy to pre-allocate. + * if this is a modify event we may need to clear the ignored masks + * otherwise return if neither the inode nor the vfsmount care about + * this type of event. */ - idx = srcu_read_lock(&fsnotify_grp_srcu); - list_for_each_entry_rcu(group, &fsnotify_groups, group_list) { - if (test_mask & group->mask) { - if (!group->ops->should_send_event(group, to_tell, mask)) - continue; - if (!event) { - event = fsnotify_create_event(to_tell, mask, data, - data_is, file_name, cookie, - GFP_KERNEL); - /* shit, we OOM'd and now we can't tell, maybe - * someday someone else will want to do something - * here */ - if (!event) - break; - } - group->ops->handle_event(group, event); + if (!(mask & FS_MODIFY) && + !(test_mask & to_tell->i_fsnotify_mask) && + !(mnt && test_mask & mnt->mnt_fsnotify_mask)) + return 0; + + idx = srcu_read_lock(&fsnotify_mark_srcu); + + if ((mask & FS_MODIFY) || + (test_mask & to_tell->i_fsnotify_mask)) + inode_node = srcu_dereference(to_tell->i_fsnotify_marks.first, + &fsnotify_mark_srcu); + else + inode_node = NULL; + + if (mnt) { + if ((mask & FS_MODIFY) || + (test_mask & mnt->mnt_fsnotify_mask)) + vfsmount_node = srcu_dereference(mnt->mnt_fsnotify_marks.first, + &fsnotify_mark_srcu); + else + vfsmount_node = NULL; + } else { + mnt = NULL; + vfsmount_node = NULL; + } + + while (inode_node || vfsmount_node) { + if (inode_node) { + inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), + struct fsnotify_mark, i.i_list); + inode_group = inode_mark->group; + } else + inode_group = (void *)-1; + + if (vfsmount_node) { + vfsmount_mark = hlist_entry(srcu_dereference(vfsmount_node, &fsnotify_mark_srcu), + struct fsnotify_mark, m.m_list); + vfsmount_group = vfsmount_mark->group; + } else + vfsmount_group = (void *)-1; + + if (inode_group < vfsmount_group) { + /* handle inode */ + send_to_group(to_tell, NULL, inode_mark, NULL, mask, data, + data_is, cookie, file_name, &event); + used_inode = true; + } else if (vfsmount_group < inode_group) { + send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data, + data_is, cookie, file_name, &event); + used_vfsmount = true; + } else { + send_to_group(to_tell, mnt, inode_mark, vfsmount_mark, + mask, data, data_is, cookie, file_name, + &event); + used_vfsmount = true; + used_inode = true; } + + if (used_inode) + inode_node = srcu_dereference(inode_node->next, + &fsnotify_mark_srcu); + if (used_vfsmount) + vfsmount_node = srcu_dereference(vfsmount_node->next, + &fsnotify_mark_srcu); } - srcu_read_unlock(&fsnotify_grp_srcu, idx); + + srcu_read_unlock(&fsnotify_mark_srcu, idx); /* * fsnotify_create_event() took a reference so the event can't be cleaned * up while we are still trying to add it to lists, drop that one. */ if (event) fsnotify_put_event(event); + + return ret; } EXPORT_SYMBOL_GPL(fsnotify); static __init int fsnotify_init(void) { - return init_srcu_struct(&fsnotify_grp_srcu); + int ret; + + BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23); + + ret = init_srcu_struct(&fsnotify_mark_srcu); + if (ret) + panic("initializing fsnotify_mark_srcu"); + + return 0; } -subsys_initcall(fsnotify_init); +core_initcall(fsnotify_init); diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 4dc240824b2d..85e7d2b431d9 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -6,21 +6,34 @@ #include <linux/srcu.h> #include <linux/types.h> -/* protects reads of fsnotify_groups */ -extern struct srcu_struct fsnotify_grp_srcu; -/* all groups which receive fsnotify events */ -extern struct list_head fsnotify_groups; -/* all bitwise OR of all event types (FS_*) for all fsnotify_groups */ -extern __u32 fsnotify_mask; - /* destroy all events sitting in this groups notification queue */ extern void fsnotify_flush_notify(struct fsnotify_group *group); +/* protects reads of inode and vfsmount marks list */ +extern struct srcu_struct fsnotify_mark_srcu; + +extern void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *fsn_mark, + __u32 mask); +/* add a mark to an inode */ +extern int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups); +/* add a mark to a vfsmount */ +extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct vfsmount *mnt, + int allow_dups); + /* final kfree of a group */ extern void fsnotify_final_destroy_group(struct fsnotify_group *group); +/* vfsmount specific destruction of a mark */ +extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark); +/* inode specific destruction of a mark */ +extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); /* run the list of all marks associated with inode and flag them to be freed */ extern void fsnotify_clear_marks_by_inode(struct inode *inode); +/* run the list of all marks associated with vfsmount and flag them to be freed */ +extern void fsnotify_clear_marks_by_mount(struct vfsmount *mnt); /* * update the dentry->d_flags of all of inode's children to indicate if inode cares * about events that happen to its children. diff --git a/fs/notify/group.c b/fs/notify/group.c index 0e1677144bc5..d309f38449cb 100644 --- a/fs/notify/group.c +++ b/fs/notify/group.c @@ -28,64 +28,6 @@ #include <asm/atomic.h> -/* protects writes to fsnotify_groups and fsnotify_mask */ -static DEFINE_MUTEX(fsnotify_grp_mutex); -/* protects reads while running the fsnotify_groups list */ -struct srcu_struct fsnotify_grp_srcu; -/* all groups registered to receive filesystem notifications */ -LIST_HEAD(fsnotify_groups); -/* bitwise OR of all events (FS_*) interesting to some group on this system */ -__u32 fsnotify_mask; - -/* - * When a new group registers or changes it's set of interesting events - * this function updates the fsnotify_mask to contain all interesting events - */ -void fsnotify_recalc_global_mask(void) -{ - struct fsnotify_group *group; - __u32 mask = 0; - int idx; - - idx = srcu_read_lock(&fsnotify_grp_srcu); - list_for_each_entry_rcu(group, &fsnotify_groups, group_list) - mask |= group->mask; - srcu_read_unlock(&fsnotify_grp_srcu, idx); - fsnotify_mask = mask; -} - -/* - * Update the group->mask by running all of the marks associated with this - * group and finding the bitwise | of all of the mark->mask. If we change - * the group->mask we need to update the global mask of events interesting - * to the system. - */ -void fsnotify_recalc_group_mask(struct fsnotify_group *group) -{ - __u32 mask = 0; - __u32 old_mask = group->mask; - struct fsnotify_mark_entry *entry; - - spin_lock(&group->mark_lock); - list_for_each_entry(entry, &group->mark_entries, g_list) - mask |= entry->mask; - spin_unlock(&group->mark_lock); - - group->mask = mask; - - if (old_mask != mask) - fsnotify_recalc_global_mask(); -} - -/* - * Take a reference to a group so things found under the fsnotify_grp_mutex - * can't get freed under us - */ -static void fsnotify_get_group(struct fsnotify_group *group) -{ - atomic_inc(&group->refcnt); -} - /* * Final freeing of a group */ @@ -110,145 +52,53 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group) */ static void fsnotify_destroy_group(struct fsnotify_group *group) { - /* clear all inode mark entries for this group */ + /* clear all inode marks for this group */ fsnotify_clear_marks_by_group(group); + synchronize_srcu(&fsnotify_mark_srcu); + /* past the point of no return, matches the initial value of 1 */ if (atomic_dec_and_test(&group->num_marks)) fsnotify_final_destroy_group(group); } /* - * Remove this group from the global list of groups that will get events - * this can be done even if there are still references and things still using - * this group. This just stops the group from getting new events. - */ -static void __fsnotify_evict_group(struct fsnotify_group *group) -{ - BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex)); - - if (group->on_group_list) - list_del_rcu(&group->group_list); - group->on_group_list = 0; -} - -/* - * Called when a group is no longer interested in getting events. This can be - * used if a group is misbehaving or if for some reason a group should no longer - * get any filesystem events. - */ -void fsnotify_evict_group(struct fsnotify_group *group) -{ - mutex_lock(&fsnotify_grp_mutex); - __fsnotify_evict_group(group); - mutex_unlock(&fsnotify_grp_mutex); -} - -/* * Drop a reference to a group. Free it if it's through. */ void fsnotify_put_group(struct fsnotify_group *group) { - if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex)) - return; - - /* - * OK, now we know that there's no other users *and* we hold mutex, - * so no new references will appear - */ - __fsnotify_evict_group(group); - - /* - * now it's off the list, so the only thing we might care about is - * srcu access.... - */ - mutex_unlock(&fsnotify_grp_mutex); - synchronize_srcu(&fsnotify_grp_srcu); - - /* and now it is really dead. _Nothing_ could be seeing it */ - fsnotify_recalc_global_mask(); - fsnotify_destroy_group(group); -} - -/* - * Simply run the fsnotify_groups list and find a group which matches - * the given parameters. If a group is found we take a reference to that - * group. - */ -static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask, - const struct fsnotify_ops *ops) -{ - struct fsnotify_group *group_iter; - struct fsnotify_group *group = NULL; - - BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex)); - - list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) { - if (group_iter->group_num == group_num) { - if ((group_iter->mask == mask) && - (group_iter->ops == ops)) { - fsnotify_get_group(group_iter); - group = group_iter; - } else - group = ERR_PTR(-EEXIST); - } - } - return group; + if (atomic_dec_and_test(&group->refcnt)) + fsnotify_destroy_group(group); } /* - * Either finds an existing group which matches the group_num, mask, and ops or - * creates a new group and adds it to the global group list. In either case we - * take a reference for the group returned. + * Create a new fsnotify_group and hold a reference for the group returned. */ -struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask, - const struct fsnotify_ops *ops) +struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) { - struct fsnotify_group *group, *tgroup; + struct fsnotify_group *group; - /* very low use, simpler locking if we just always alloc */ - group = kmalloc(sizeof(struct fsnotify_group), GFP_KERNEL); + group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL); if (!group) return ERR_PTR(-ENOMEM); + /* set to 0 when there a no external references to this group */ atomic_set(&group->refcnt, 1); - - group->on_group_list = 0; - group->group_num = group_num; - group->mask = mask; + /* + * hits 0 when there are no external references AND no marks for + * this group + */ + atomic_set(&group->num_marks, 1); mutex_init(&group->notification_mutex); INIT_LIST_HEAD(&group->notification_list); init_waitqueue_head(&group->notification_waitq); - group->q_len = 0; group->max_events = UINT_MAX; spin_lock_init(&group->mark_lock); - atomic_set(&group->num_marks, 0); - INIT_LIST_HEAD(&group->mark_entries); + INIT_LIST_HEAD(&group->marks_list); group->ops = ops; - mutex_lock(&fsnotify_grp_mutex); - tgroup = fsnotify_find_group(group_num, mask, ops); - if (tgroup) { - /* group already exists */ - mutex_unlock(&fsnotify_grp_mutex); - /* destroy the new one we made */ - fsnotify_put_group(group); - return tgroup; - } - - /* group not found, add a new one */ - list_add_rcu(&group->group_list, &fsnotify_groups); - group->on_group_list = 1; - /* being on the fsnotify_groups list holds one num_marks */ - atomic_inc(&group->num_marks); - - mutex_unlock(&fsnotify_grp_mutex); - - if (mask) - fsnotify_recalc_global_mask(); - return group; } diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 0399bcbe09c8..33297c005060 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -16,72 +16,6 @@ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ -/* - * fsnotify inode mark locking/lifetime/and refcnting - * - * REFCNT: - * The mark->refcnt tells how many "things" in the kernel currently are - * referencing this object. The object typically will live inside the kernel - * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task - * which can find this object holding the appropriete locks, can take a reference - * and the object itself is guarenteed to survive until the reference is dropped. - * - * LOCKING: - * There are 3 spinlocks involved with fsnotify inode marks and they MUST - * be taken in order as follows: - * - * entry->lock - * group->mark_lock - * inode->i_lock - * - * entry->lock protects 2 things, entry->group and entry->inode. You must hold - * that lock to dereference either of these things (they could be NULL even with - * the lock) - * - * group->mark_lock protects the mark_entries list anchored inside a given group - * and each entry is hooked via the g_list. It also sorta protects the - * free_g_list, which when used is anchored by a private list on the stack of the - * task which held the group->mark_lock. - * - * inode->i_lock protects the i_fsnotify_mark_entries list anchored inside a - * given inode and each entry is hooked via the i_list. (and sorta the - * free_i_list) - * - * - * LIFETIME: - * Inode marks survive between when they are added to an inode and when their - * refcnt==0. - * - * The inode mark can be cleared for a number of different reasons including: - * - The inode is unlinked for the last time. (fsnotify_inode_remove) - * - The inode is being evicted from cache. (fsnotify_inode_delete) - * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) - * - Something explicitly requests that it be removed. (fsnotify_destroy_mark_by_entry) - * - The fsnotify_group associated with the mark is going away and all such marks - * need to be cleaned up. (fsnotify_clear_marks_by_group) - * - * Worst case we are given an inode and need to clean up all the marks on that - * inode. We take i_lock and walk the i_fsnotify_mark_entries safely. For each - * mark on the list we take a reference (so the mark can't disappear under us). - * We remove that mark form the inode's list of marks and we add this mark to a - * private list anchored on the stack using i_free_list; At this point we no - * longer fear anything finding the mark using the inode's list of marks. - * - * We can safely and locklessly run the private list on the stack of everything - * we just unattached from the original inode. For each mark on the private list - * we grab the mark-> and can thus dereference mark->group and mark->inode. If - * we see the group and inode are not NULL we take those locks. Now holding all - * 3 locks we can completely remove the mark from other tasks finding it in the - * future. Remember, 10 things might already be referencing this mark, but they - * better be holding a ref. We drop our reference we took before we unhooked it - * from the inode. When the ref hits 0 we can free the mark. - * - * Very similarly for freeing by group, except we use free_g_list. - * - * This has the very interesting property of being able to run concurrently with - * any (or all) other directions. - */ - #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> @@ -95,30 +29,19 @@ #include <linux/fsnotify_backend.h> #include "fsnotify.h" -void fsnotify_get_mark(struct fsnotify_mark_entry *entry) -{ - atomic_inc(&entry->refcnt); -} - -void fsnotify_put_mark(struct fsnotify_mark_entry *entry) -{ - if (atomic_dec_and_test(&entry->refcnt)) - entry->free_mark(entry); -} - /* * Recalculate the mask of events relevant to a given inode locked. */ static void fsnotify_recalc_inode_mask_locked(struct inode *inode) { - struct fsnotify_mark_entry *entry; + struct fsnotify_mark *mark; struct hlist_node *pos; __u32 new_mask = 0; assert_spin_locked(&inode->i_lock); - hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) - new_mask |= entry->mask; + hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) + new_mask |= mark->mask; inode->i_fsnotify_mask = new_mask; } @@ -135,107 +58,26 @@ void fsnotify_recalc_inode_mask(struct inode *inode) __fsnotify_update_child_dentry_flags(inode); } -/* - * Any time a mark is getting freed we end up here. - * The caller had better be holding a reference to this mark so we don't actually - * do the final put under the entry->lock - */ -void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry) +void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) { - struct fsnotify_group *group; - struct inode *inode; + struct inode *inode = mark->i.inode; - spin_lock(&entry->lock); + assert_spin_locked(&mark->lock); + assert_spin_locked(&mark->group->mark_lock); - group = entry->group; - inode = entry->inode; - - BUG_ON(group && !inode); - BUG_ON(!group && inode); - - /* if !group something else already marked this to die */ - if (!group) { - spin_unlock(&entry->lock); - return; - } - - /* 1 from caller and 1 for being on i_list/g_list */ - BUG_ON(atomic_read(&entry->refcnt) < 2); - - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); - hlist_del_init(&entry->i_list); - entry->inode = NULL; - - list_del_init(&entry->g_list); - entry->group = NULL; - - fsnotify_put_mark(entry); /* for i_list and g_list */ + hlist_del_init_rcu(&mark->i.i_list); + mark->i.inode = NULL; /* - * this mark is now off the inode->i_fsnotify_mark_entries list and we + * this mark is now off the inode->i_fsnotify_marks list and we * hold the inode->i_lock, so this is the perfect time to update the * inode->i_fsnotify_mask */ fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&entry->lock); - - /* - * Some groups like to know that marks are being freed. This is a - * callback to the group function to let it know that this entry - * is being freed. - */ - if (group->ops->freeing_mark) - group->ops->freeing_mark(entry, group); - - /* - * __fsnotify_update_child_dentry_flags(inode); - * - * I really want to call that, but we can't, we have no idea if the inode - * still exists the second we drop the entry->lock. - * - * The next time an event arrive to this inode from one of it's children - * __fsnotify_parent will see that the inode doesn't care about it's - * children and will update all of these flags then. So really this - * is just a lazy update (and could be a perf win...) - */ - - - iput(inode); - - /* - * it's possible that this group tried to destroy itself, but this - * this mark was simultaneously being freed by inode. If that's the - * case, we finish freeing the group here. - */ - if (unlikely(atomic_dec_and_test(&group->num_marks))) - fsnotify_final_destroy_group(group); -} - -/* - * Given a group, destroy all of the marks associated with that group. - */ -void fsnotify_clear_marks_by_group(struct fsnotify_group *group) -{ - struct fsnotify_mark_entry *lentry, *entry; - LIST_HEAD(free_list); - - spin_lock(&group->mark_lock); - list_for_each_entry_safe(entry, lentry, &group->mark_entries, g_list) { - list_add(&entry->free_g_list, &free_list); - list_del_init(&entry->g_list); - fsnotify_get_mark(entry); - } - spin_unlock(&group->mark_lock); - - list_for_each_entry_safe(entry, lentry, &free_list, free_g_list) { - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); - } } /* @@ -243,112 +85,145 @@ void fsnotify_clear_marks_by_group(struct fsnotify_group *group) */ void fsnotify_clear_marks_by_inode(struct inode *inode) { - struct fsnotify_mark_entry *entry, *lentry; + struct fsnotify_mark *mark, *lmark; struct hlist_node *pos, *n; LIST_HEAD(free_list); spin_lock(&inode->i_lock); - hlist_for_each_entry_safe(entry, pos, n, &inode->i_fsnotify_mark_entries, i_list) { - list_add(&entry->free_i_list, &free_list); - hlist_del_init(&entry->i_list); - fsnotify_get_mark(entry); + hlist_for_each_entry_safe(mark, pos, n, &inode->i_fsnotify_marks, i.i_list) { + list_add(&mark->i.free_i_list, &free_list); + hlist_del_init_rcu(&mark->i.i_list); + fsnotify_get_mark(mark); } spin_unlock(&inode->i_lock); - list_for_each_entry_safe(entry, lentry, &free_list, free_i_list) { - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); + list_for_each_entry_safe(mark, lmark, &free_list, i.free_i_list) { + fsnotify_destroy_mark(mark); + fsnotify_put_mark(mark); } } /* + * Given a group clear all of the inode marks associated with that group. + */ +void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) +{ + fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_INODE); +} + +/* * given a group and inode, find the mark associated with that combination. * if found take a reference to that mark and return it, else return NULL */ -struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group, - struct inode *inode) +struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group, + struct inode *inode) { - struct fsnotify_mark_entry *entry; + struct fsnotify_mark *mark; struct hlist_node *pos; assert_spin_locked(&inode->i_lock); - hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) { - if (entry->group == group) { - fsnotify_get_mark(entry); - return entry; + hlist_for_each_entry(mark, pos, &inode->i_fsnotify_marks, i.i_list) { + if (mark->group == group) { + fsnotify_get_mark(mark); + return mark; } } return NULL; } /* - * Nothing fancy, just initialize lists and locks and counters. + * given a group and inode, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL */ -void fsnotify_init_mark(struct fsnotify_mark_entry *entry, - void (*free_mark)(struct fsnotify_mark_entry *entry)) +struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, + struct inode *inode) +{ + struct fsnotify_mark *mark; + + spin_lock(&inode->i_lock); + mark = fsnotify_find_inode_mark_locked(group, inode); + spin_unlock(&inode->i_lock); + return mark; +} + +/* + * If we are setting a mark mask on an inode mark we should pin the inode + * in memory. + */ +void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, + __u32 mask) { - spin_lock_init(&entry->lock); - atomic_set(&entry->refcnt, 1); - INIT_HLIST_NODE(&entry->i_list); - entry->group = NULL; - entry->mask = 0; - entry->inode = NULL; - entry->free_mark = free_mark; + struct inode *inode; + + assert_spin_locked(&mark->lock); + + if (mask && + mark->i.inode && + !(mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) { + mark->flags |= FSNOTIFY_MARK_FLAG_OBJECT_PINNED; + inode = igrab(mark->i.inode); + /* + * we shouldn't be able to get here if the inode wasn't + * already safely held in memory. But bug in case it + * ever is wrong. + */ + BUG_ON(!inode); + } } /* - * Attach an initialized mark entry to a given group and inode. + * Attach an initialized mark to a given inode. * These marks may be used for the fsnotify backend to determine which - * event types should be delivered to which group and for which inodes. + * event types should be delivered to which group and for which inodes. These + * marks are ordered according to the group's location in memory. */ -int fsnotify_add_mark(struct fsnotify_mark_entry *entry, - struct fsnotify_group *group, struct inode *inode) +int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups) { - struct fsnotify_mark_entry *lentry; + struct fsnotify_mark *lmark; + struct hlist_node *node, *last = NULL; int ret = 0; - inode = igrab(inode); - if (unlikely(!inode)) - return -EINVAL; + mark->flags |= FSNOTIFY_MARK_FLAG_INODE; + + assert_spin_locked(&mark->lock); + assert_spin_locked(&group->mark_lock); - /* - * LOCKING ORDER!!!! - * entry->lock - * group->mark_lock - * inode->i_lock - */ - spin_lock(&entry->lock); - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); - lentry = fsnotify_find_mark_entry(group, inode); - if (!lentry) { - entry->group = group; - entry->inode = inode; + mark->i.inode = inode; - hlist_add_head(&entry->i_list, &inode->i_fsnotify_mark_entries); - list_add(&entry->g_list, &group->mark_entries); + /* is mark the first mark? */ + if (hlist_empty(&inode->i_fsnotify_marks)) { + hlist_add_head_rcu(&mark->i.i_list, &inode->i_fsnotify_marks); + goto out; + } - fsnotify_get_mark(entry); /* for i_list and g_list */ + /* should mark be in the middle of the current list? */ + hlist_for_each_entry(lmark, node, &inode->i_fsnotify_marks, i.i_list) { + last = node; + + if ((lmark->group == group) && !allow_dups) { + ret = -EEXIST; + goto out; + } - atomic_inc(&group->num_marks); + if (mark->group < lmark->group) + continue; - fsnotify_recalc_inode_mask_locked(inode); + hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); + goto out; } + BUG_ON(last == NULL); + /* mark should be the last entry. last is the current last entry */ + hlist_add_after_rcu(last, &mark->i.i_list); +out: + fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&entry->lock); - - if (lentry) { - ret = -EEXIST; - iput(inode); - fsnotify_put_mark(lentry); - } else { - __fsnotify_update_child_dentry_flags(inode); - } return ret; } @@ -369,11 +244,11 @@ void fsnotify_unmount_inodes(struct list_head *list) struct inode *need_iput_tmp; /* - * We cannot __iget() an inode in state I_CLEAR, I_FREEING, + * We cannot __iget() an inode in state I_FREEING, * I_WILL_FREE, or I_NEW which is fine because by that point * the inode cannot have any associated watches. */ - if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) + if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) continue; /* @@ -397,7 +272,7 @@ void fsnotify_unmount_inodes(struct list_head *list) /* 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))) { + !(next_i->i_state & (I_FREEING | I_WILL_FREE))) { __iget(next_i); need_iput = next_i; } diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig index b3a159b21cfd..b981fc0c8379 100644 --- a/fs/notify/inotify/Kconfig +++ b/fs/notify/inotify/Kconfig @@ -1,18 +1,3 @@ -config INOTIFY - bool "Inotify file change notification support" - default n - ---help--- - Say Y here to enable legacy in kernel inotify support. Inotify is a - file change notification system. It is a replacement for dnotify. - This option only provides the legacy inotify in kernel API. There - are no in tree kernel users of this interface since it is deprecated. - You only need this if you are loading an out of tree kernel module - that uses inotify. - - For more information, see <file:Documentation/filesystems/inotify.txt> - - If unsure, say N. - config INOTIFY_USER bool "Inotify support for userspace" select ANON_INODES diff --git a/fs/notify/inotify/Makefile b/fs/notify/inotify/Makefile index 943828171362..a380dabe09de 100644 --- a/fs/notify/inotify/Makefile +++ b/fs/notify/inotify/Makefile @@ -1,2 +1 @@ -obj-$(CONFIG_INOTIFY) += inotify.o obj-$(CONFIG_INOTIFY_USER) += inotify_fsnotify.o inotify_user.o diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c deleted file mode 100644 index 27b75ebc7460..000000000000 --- a/fs/notify/inotify/inotify.c +++ /dev/null @@ -1,873 +0,0 @@ -/* - * fs/inotify.c - inode-based file event notifications - * - * Authors: - * John McCutchan <ttb@tentacle.dhs.org> - * Robert Love <rml@novell.com> - * - * Kernel API added by: Amy Griffis <amy.griffis@hp.com> - * - * 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 - * Free Software Foundation; either version 2, or (at your option) any - * later version. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - */ - -#include <linux/module.h> -#include <linux/kernel.h> -#include <linux/spinlock.h> -#include <linux/idr.h> -#include <linux/slab.h> -#include <linux/fs.h> -#include <linux/sched.h> -#include <linux/init.h> -#include <linux/list.h> -#include <linux/writeback.h> -#include <linux/inotify.h> -#include <linux/fsnotify_backend.h> - -static atomic_t inotify_cookie; - -/* - * Lock ordering: - * - * dentry->d_lock (used to keep d_move() away from dentry->d_parent) - * iprune_mutex (synchronize shrink_icache_memory()) - * inode_lock (protects the super_block->s_inodes 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_handle, inode, and - * inotify_watch--are managed by reference count. - * - * 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: 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 - * inotify_add_watch() to the final put_inotify_watch(). - */ - -/* - * struct inotify_handle - represents an inotify instance - * - * This structure is protected by the mutex 'mutex'. - */ -struct inotify_handle { - struct idr idr; /* idr mapping wd -> watch */ - struct mutex mutex; /* protects this bad boy */ - struct list_head watches; /* list of watches */ - atomic_t count; /* reference count */ - u32 last_wd; /* the last wd allocated */ - const struct inotify_operations *in_ops; /* inotify caller operations */ -}; - -static inline void get_inotify_handle(struct inotify_handle *ih) -{ - atomic_inc(&ih->count); -} - -static inline void put_inotify_handle(struct inotify_handle *ih) -{ - if (atomic_dec_and_test(&ih->count)) { - idr_destroy(&ih->idr); - kfree(ih); - } -} - -/** - * 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); - -int pin_inotify_watch(struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - if (atomic_inc_not_zero(&sb->s_active)) { - atomic_inc(&watch->count); - return 1; - } - return 0; -} - -/** - * put_inotify_watch - decrements the ref count on a given watch. cleans up - * watch references if the count reaches zero. inotify_watch is freed by - * inotify callers via the destroy_watch() op. - * @watch: watch to release - */ -void put_inotify_watch(struct inotify_watch *watch) -{ - if (atomic_dec_and_test(&watch->count)) { - struct inotify_handle *ih = watch->ih; - - iput(watch->inode); - ih->in_ops->destroy_watch(watch); - put_inotify_handle(ih); - } -} -EXPORT_SYMBOL_GPL(put_inotify_watch); - -void unpin_inotify_watch(struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - put_inotify_watch(watch); - deactivate_super(sb); -} - -/* - * inotify_handle_get_wd - returns the next WD for use by the given handle - * - * Callers must hold ih->mutex. This function can sleep. - */ -static int inotify_handle_get_wd(struct inotify_handle *ih, - struct inotify_watch *watch) -{ - int ret; - - do { - if (unlikely(!idr_pre_get(&ih->idr, GFP_NOFS))) - return -ENOSPC; - 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; -} - -/* - * 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) - continue; - - spin_lock(&child->d_lock); - if (watched) - child->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED; - else - child->d_flags &=~DCACHE_INOTIFY_PARENT_WATCHED; - spin_unlock(&child->d_lock); - } - } - spin_unlock(&dcache_lock); -} - -/* - * inotify_find_handle - find the watch associated with the given inode and - * handle - * - * Callers must hold inode->inotify_mutex. - */ -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->ih == ih) - return watch; - } - - return NULL; -} - -/* - * 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_handle *ih) -{ - list_del(&watch->i_list); - list_del(&watch->h_list); - - if (!inotify_inode_watched(watch->inode)) - set_dentry_child_flags(watch->inode, 0); - - idr_remove(&ih->idr, watch->wd); -} - -/** - * 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 - * - * Callers must hold both inode->inotify_mutex and ih->mutex. - */ -void inotify_remove_watch_locked(struct inotify_handle *ih, - struct inotify_watch *watch) -{ - 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_d_instantiate - instantiate dcache entry for inode - */ -void inotify_d_instantiate(struct dentry *entry, struct inode *inode) -{ - struct dentry *parent; - - if (!inode) - return; - - 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); -} - -/* - * 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 - * @inode: inode event is originating from - * @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, struct inode *n_inode) -{ - struct inotify_watch *watch, *next; - - if (!inotify_inode_watched(inode)) - return; - - 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_handle *ih= watch->ih; - mutex_lock(&ih->mutex); - if (watch_mask & IN_ONESHOT) - remove_watch_no_event(watch, ih); - ih->in_ops->handle_event(watch, watch->wd, mask, cookie, - name, n_inode); - mutex_unlock(&ih->mutex); - } - } - mutex_unlock(&inode->inotify_mutex); -} -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; - - if (!(dentry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED)) - return; - - 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, - dentry->d_inode); - 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_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) -{ - 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; - - /* - * We cannot __iget() an inode in state I_CLEAR, I_FREEING, - * I_WILL_FREE, or I_NEW which is fine because by that point - * the inode cannot have any associated watches. - */ - if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW)) - continue; - - /* - * If i_count is zero, the inode cannot have any watches and - * doing an __iget/iput with MS_ACTIVE clear would actually - * evict all inodes with zero i_count from icache which is - * unnecessarily violent and may in fact be illegal to do. - */ - if (!atomic_read(&inode->i_count)) - continue; - - need_iput_tmp = need_iput; - need_iput = NULL; - /* In case inotify_remove_watch_locked() drops a reference. */ - if (inode != need_iput_tmp) - __iget(inode); - else - need_iput_tmp = NULL; - /* In case the dropping of a reference would nuke next_i. */ - if ((&next_i->i_sb_list != list) && - atomic_read(&next_i->i_count) && - !(next_i->i_state & (I_CLEAR | I_FREEING | - I_WILL_FREE))) { - __iget(next_i); - need_iput = next_i; - } - - /* - * We can safely drop inode_lock here because we hold - * references on both inode and next_i. Also no new inodes - * will be added since the umount has begun. Finally, - * iprune_mutex keeps shrink_icache_memory() away. - */ - spin_unlock(&inode_lock); - - if (need_iput_tmp) - iput(need_iput_tmp); - - /* for each watch, send IN_UNMOUNT and then remove it */ - mutex_lock(&inode->inotify_mutex); - watches = &inode->inotify_watches; - list_for_each_entry_safe(watch, next_w, watches, i_list) { - struct inotify_handle *ih= watch->ih; - get_inotify_watch(watch); - 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); - put_inotify_watch(watch); - } - mutex_unlock(&inode->inotify_mutex); - 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; - - mutex_lock(&inode->inotify_mutex); - list_for_each_entry_safe(watch, next, &inode->inotify_watches, i_list) { - struct inotify_handle *ih = watch->ih; - mutex_lock(&ih->mutex); - inotify_remove_watch_locked(ih, watch); - mutex_unlock(&ih->mutex); - } - mutex_unlock(&inode->inotify_mutex); -} -EXPORT_SYMBOL_GPL(inotify_inode_is_dead); - -/* Kernel Consumer API */ - -/** - * 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_handle *ih; - - ih = kmalloc(sizeof(struct inotify_handle), GFP_KERNEL); - if (unlikely(!ih)) - return ERR_PTR(-ENOMEM); - - 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); - -/** - * inotify_init_watch - initialize an inotify watch - * @watch: watch to initialize - */ -void inotify_init_watch(struct inotify_watch *watch) -{ - 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); - -/* - * Watch removals suck violently. To kick the watch out we need (in this - * order) inode->inotify_mutex and ih->mutex. That's fine if we have - * a hold on inode; however, for all other cases we need to make damn sure - * we don't race with umount. We can *NOT* just grab a reference to a - * watch - inotify_unmount_inodes() will happily sail past it and we'll end - * with reference to inode potentially outliving its superblock. Ideally - * we just want to grab an active reference to superblock if we can; that - * will make sure we won't go into inotify_umount_inodes() until we are - * done. Cleanup is just deactivate_super(). However, that leaves a messy - * case - what if we *are* racing with umount() and active references to - * superblock can't be acquired anymore? We can bump ->s_count, grab - * ->s_umount, which will wait until the superblock is shut down and the - * watch in question is pining for fjords. - * - * And yes, this is far beyond mere "not very pretty"; so's the entire - * concept of inotify to start with. - */ - -/** - * pin_to_kill - pin the watch down for removal - * @ih: inotify handle - * @watch: watch to kill - * - * Called with ih->mutex held, drops it. Possible return values: - * 0 - nothing to do, it has died - * 1 - remove it, drop the reference and deactivate_super() - */ -static int pin_to_kill(struct inotify_handle *ih, struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - - if (atomic_inc_not_zero(&sb->s_active)) { - get_inotify_watch(watch); - mutex_unlock(&ih->mutex); - return 1; /* the best outcome */ - } - spin_lock(&sb_lock); - sb->s_count++; - spin_unlock(&sb_lock); - mutex_unlock(&ih->mutex); /* can't grab ->s_umount under it */ - down_read(&sb->s_umount); - /* fs is already shut down; the watch is dead */ - drop_super(sb); - return 0; -} - -static void unpin_and_kill(struct inotify_watch *watch) -{ - struct super_block *sb = watch->inode->i_sb; - put_inotify_watch(watch); - deactivate_super(sb); -} - -/** - * inotify_destroy - clean up and destroy an inotify instance - * @ih: inotify handle - */ -void inotify_destroy(struct inotify_handle *ih) -{ - /* - * 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_mutex before ih->mutex. The following works. - * - * AV: it had to become even uglier to start working ;-/ - */ - while (1) { - struct inotify_watch *watch; - struct list_head *watches; - struct super_block *sb; - struct inode *inode; - - mutex_lock(&ih->mutex); - watches = &ih->watches; - if (list_empty(watches)) { - mutex_unlock(&ih->mutex); - break; - } - watch = list_first_entry(watches, struct inotify_watch, h_list); - sb = watch->inode->i_sb; - if (!pin_to_kill(ih, watch)) - continue; - - inode = watch->inode; - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* 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); - } - - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - unpin_and_kill(watch); - } - - /* free this handle: the put matching the get in inotify_init() */ - put_inotify_handle(ih); -} -EXPORT_SYMBOL_GPL(inotify_destroy); - -/** - * 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 - * - * Caller must pin given inode (via nameidata). - */ -s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, - struct inotify_watch **watchp) -{ - struct inotify_watch *old; - int ret = -ENOENT; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - old = inode_find_handle(inode, ih); - if (unlikely(old)) { - get_inotify_watch(old); /* caller must put watch */ - *watchp = old; - ret = old->wd; - } - - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - - return ret; -} -EXPORT_SYMBOL_GPL(inotify_find_watch); - -/** - * 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_watch *old; - int mask_add = 0; - int ret; - - if (mask & IN_MASK_ADD) - mask_add = 1; - - /* don't allow invalid bits: we don't want flags set */ - mask &= IN_ALL_EVENTS | IN_ONESHOT; - if (unlikely(!mask)) - return -EINVAL; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* - * 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; - } - - 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); - -/** - * 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) -{ - int ret = 0; - int newly_watched; - - /* 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; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* Initialize a new watch */ - ret = inotify_handle_get_wd(ih, watch); - if (unlikely(ret)) - 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; - - /* - * 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); - - /* Add the watch to the handle's and the inode's list */ - newly_watched = !inotify_inode_watched(inode); - list_add(&watch->h_list, &ih->watches); - list_add(&watch->i_list, &inode->inotify_watches); - /* - * Set child flags _after_ adding the watch, so there is no race - * windows where newly instantiated children could miss their parent's - * watched flag. - */ - if (newly_watched) - set_dentry_child_flags(inode, 1); - -out: - mutex_unlock(&ih->mutex); - mutex_unlock(&inode->inotify_mutex); - return ret; -} -EXPORT_SYMBOL_GPL(inotify_add_watch); - -/** - * inotify_clone_watch - put the watch next to existing one - * @old: already installed watch - * @new: new watch - * - * Caller must hold the inotify_mutex of inode we are dealing with; - * it is expected to remove the old watch before unlocking the inode. - */ -s32 inotify_clone_watch(struct inotify_watch *old, struct inotify_watch *new) -{ - struct inotify_handle *ih = old->ih; - int ret = 0; - - new->mask = old->mask; - new->ih = ih; - - mutex_lock(&ih->mutex); - - /* Initialize a new watch */ - ret = inotify_handle_get_wd(ih, new); - if (unlikely(ret)) - goto out; - ret = new->wd; - - get_inotify_handle(ih); - - new->inode = igrab(old->inode); - - list_add(&new->h_list, &ih->watches); - list_add(&new->i_list, &old->inode->inotify_watches); -out: - mutex_unlock(&ih->mutex); - return ret; -} - -void inotify_evict_watch(struct inotify_watch *watch) -{ - get_inotify_watch(watch); - mutex_lock(&watch->ih->mutex); - inotify_remove_watch_locked(watch->ih, watch); - mutex_unlock(&watch->ih->mutex); -} - -/** - * 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 inotify_watch *watch; - struct super_block *sb; - struct inode *inode; - - mutex_lock(&ih->mutex); - watch = idr_find(&ih->idr, wd); - if (unlikely(!watch)) { - mutex_unlock(&ih->mutex); - return -EINVAL; - } - sb = watch->inode->i_sb; - if (!pin_to_kill(ih, watch)) - return 0; - - inode = watch->inode; - - mutex_lock(&inode->inotify_mutex); - mutex_lock(&ih->mutex); - - /* 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); - unpin_and_kill(watch); - - return 0; -} -EXPORT_SYMBOL_GPL(inotify_rm_wd); - -/** - * 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 inotify_rm_wd(ih, watch->wd); -} -EXPORT_SYMBOL_GPL(inotify_rm_watch); - -/* - * inotify_setup - core initialization function - */ -static int __init inotify_setup(void) -{ - BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); - BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); - BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); - BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); - BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); - BUILD_BUG_ON(IN_OPEN != FS_OPEN); - BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); - BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); - BUILD_BUG_ON(IN_CREATE != FS_CREATE); - BUILD_BUG_ON(IN_DELETE != FS_DELETE); - BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); - BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); - BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); - - BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); - BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR); - BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); - BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); - - atomic_set(&inotify_cookie, 0); - - return 0; -} - -module_init(inotify_setup); diff --git a/fs/notify/inotify/inotify.h b/fs/notify/inotify/inotify.h index f234f3a4c8ca..b6642e4de4bf 100644 --- a/fs/notify/inotify/inotify.h +++ b/fs/notify/inotify/inotify.h @@ -9,13 +9,12 @@ struct inotify_event_private_data { int wd; }; -struct inotify_inode_mark_entry { - /* fsnotify_mark_entry MUST be the first thing */ - struct fsnotify_mark_entry fsn_entry; +struct inotify_inode_mark { + struct fsnotify_mark fsn_mark; int wd; }; -extern void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, +extern void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group); extern void inotify_free_event_priv(struct fsnotify_event_private_data *event_priv); diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index e27960cd76ab..a91b69a6a291 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -22,6 +22,7 @@ * General Public License for more details. */ +#include <linux/dcache.h> /* d_unlinked */ #include <linux/fs.h> /* struct inode */ #include <linux/fsnotify_backend.h> #include <linux/inotify.h> @@ -32,26 +33,84 @@ #include "inotify.h" -static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event) +/* + * Check if 2 events contain the same information. We do not compare private data + * but at this moment that isn't a problem for any know fsnotify listeners. + */ +static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) +{ + if ((old->mask == new->mask) && + (old->to_tell == new->to_tell) && + (old->data_type == new->data_type) && + (old->name_len == new->name_len)) { + switch (old->data_type) { + case (FSNOTIFY_EVENT_INODE): + /* remember, after old was put on the wait_q we aren't + * allowed to look at the inode any more, only thing + * left to check was if the file_name is the same */ + if (!old->name_len || + !strcmp(old->file_name, new->file_name)) + return true; + break; + case (FSNOTIFY_EVENT_PATH): + if ((old->path.mnt == new->path.mnt) && + (old->path.dentry == new->path.dentry)) + return true; + break; + case (FSNOTIFY_EVENT_NONE): + if (old->mask & FS_Q_OVERFLOW) + return true; + else if (old->mask & FS_IN_IGNORED) + return false; + return true; + }; + } + return false; +} + +static struct fsnotify_event *inotify_merge(struct list_head *list, + struct fsnotify_event *event) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; + struct fsnotify_event_holder *last_holder; + struct fsnotify_event *last_event; + + /* and the list better be locked by something too */ + spin_lock(&event->lock); + + last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list); + last_event = last_holder->event; + if (event_compare(last_event, event)) + fsnotify_get_event(last_event); + else + last_event = NULL; + + spin_unlock(&event->lock); + + return last_event; +} + +static int inotify_handle_event(struct fsnotify_group *group, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + struct fsnotify_event *event) +{ + struct inotify_inode_mark *i_mark; struct inode *to_tell; struct inotify_event_private_data *event_priv; struct fsnotify_event_private_data *fsn_event_priv; - int wd, ret; + struct fsnotify_event *added_event; + int wd, ret = 0; + + BUG_ON(vfsmount_mark); + + pr_debug("%s: group=%p event=%p to_tell=%p mask=%x\n", __func__, group, + event, event->to_tell, event->mask); to_tell = event->to_tell; - spin_lock(&to_tell->i_lock); - entry = fsnotify_find_mark_entry(group, to_tell); - spin_unlock(&to_tell->i_lock); - /* race with watch removal? We already passes should_send */ - if (unlikely(!entry)) - return 0; - ientry = container_of(entry, struct inotify_inode_mark_entry, - fsn_entry); - wd = ientry->wd; + i_mark = container_of(inode_mark, struct inotify_inode_mark, + fsn_mark); + wd = i_mark->wd; event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); if (unlikely(!event_priv)) @@ -62,48 +121,40 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev fsn_event_priv->group = group; event_priv->wd = wd; - ret = fsnotify_add_notify_event(group, event, fsn_event_priv); - if (ret) { + added_event = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge); + if (added_event) { inotify_free_event_priv(fsn_event_priv); - /* EEXIST says we tail matched, EOVERFLOW isn't something - * to report up the stack. */ - if ((ret == -EEXIST) || - (ret == -EOVERFLOW)) - ret = 0; + if (!IS_ERR(added_event)) + fsnotify_put_event(added_event); + else + ret = PTR_ERR(added_event); } - /* - * If we hold the entry until after the event is on the queue - * IN_IGNORED won't be able to pass this event in the queue - */ - fsnotify_put_mark(entry); + if (inode_mark->mask & IN_ONESHOT) + fsnotify_destroy_mark(inode_mark); return ret; } -static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group) +static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) { - inotify_ignored_and_remove_idr(entry, group); + inotify_ignored_and_remove_idr(fsn_mark, group); } -static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask) +static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + __u32 mask, void *data, int data_type) { - struct fsnotify_mark_entry *entry; - bool send; - - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); - if (!entry) - return false; + if ((inode_mark->mask & FS_EXCL_UNLINK) && + (data_type == FSNOTIFY_EVENT_PATH)) { + struct path *path = data; - mask = (mask & ~FS_EVENT_ON_CHILD); - send = (entry->mask & mask); - - /* find took a reference */ - fsnotify_put_mark(entry); + if (d_unlinked(path->dentry)) + return false; + } - return send; + return true; } /* @@ -115,18 +166,18 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode */ static int idr_callback(int id, void *p, void *data) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; static bool warned = false; if (warned) return 0; warned = true; - entry = p; - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + fsn_mark = p; + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); - WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in " + WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " "idr. Probably leaking memory\n", id, p, data); /* @@ -135,9 +186,9 @@ static int idr_callback(int id, void *p, void *data) * out why we got here and the panic is no worse than the original * BUG() that was here. */ - if (entry) - printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n", - entry->group, entry->inode, ientry->wd); + if (fsn_mark) + printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", + fsn_mark->group, fsn_mark->i.inode, i_mark->wd); return 0; } diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index e46ca685b9be..bf7f6d776c31 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -46,17 +46,11 @@ /* these are configurable via /proc/sys/fs/inotify/ */ static int inotify_max_user_instances __read_mostly; static int inotify_max_queued_events __read_mostly; -int inotify_max_user_watches __read_mostly; +static int inotify_max_user_watches __read_mostly; static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; struct kmem_cache *event_priv_cachep __read_mostly; -/* - * When inotify registers a new group it increments this and uses that - * value as an offset to set the fsnotify group "name" and priority. - */ -static atomic_t inotify_grp_num; - #ifdef CONFIG_SYSCTL #include <linux/sysctl.h> @@ -96,11 +90,14 @@ static inline __u32 inotify_arg_to_mask(u32 arg) { __u32 mask; - /* everything should accept their own ignored and cares about children */ - mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD); + /* + * everything should accept their own ignored, cares about children, + * and should receive events when the inode is unmounted + */ + mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD | FS_UNMOUNT); /* mask off the flags used to open the fd */ - mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT)); + mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT | IN_EXCL_UNLINK)); return mask; } @@ -144,6 +141,8 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group, event = fsnotify_peek_notify_event(group); + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + if (event->name_len) event_size += roundup(event->name_len + 1, event_size); @@ -173,6 +172,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, size_t event_size = sizeof(struct inotify_event); size_t name_len = 0; + pr_debug("%s: group=%p event=%p\n", __func__, group, event); + /* we get the inotify watch descriptor from the event private data */ spin_lock(&event->lock); fsn_priv = fsnotify_remove_priv_from_event(group, event); @@ -245,6 +246,8 @@ static ssize_t inotify_read(struct file *file, char __user *buf, kevent = get_one_event(group, count); mutex_unlock(&group->notification_mutex); + pr_debug("%s: group=%p kevent=%p\n", __func__, group, kevent); + if (kevent) { ret = PTR_ERR(kevent); if (IS_ERR(kevent)) @@ -289,6 +292,8 @@ static int inotify_release(struct inode *ignored, struct file *file) struct fsnotify_group *group = file->private_data; struct user_struct *user = group->inotify_data.user; + pr_debug("%s: group=%p\n", __func__, group); + fsnotify_clear_marks_by_group(group); /* free this group, matching get was inotify_init->fsnotify_obtain_group */ @@ -312,6 +317,8 @@ static long inotify_ioctl(struct file *file, unsigned int cmd, group = file->private_data; p = (void __user *) arg; + pr_debug("%s: group=%p cmd=%u\n", __func__, group, cmd); + switch (cmd) { case FIONREAD: mutex_lock(&group->notification_mutex); @@ -357,59 +364,159 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns return error; } +static int inotify_add_to_idr(struct idr *idr, spinlock_t *idr_lock, + int *last_wd, + struct inotify_inode_mark *i_mark) +{ + int ret; + + do { + if (unlikely(!idr_pre_get(idr, GFP_KERNEL))) + return -ENOMEM; + + spin_lock(idr_lock); + ret = idr_get_new_above(idr, i_mark, *last_wd + 1, + &i_mark->wd); + /* we added the mark to the idr, take a reference */ + if (!ret) { + *last_wd = i_mark->wd; + fsnotify_get_mark(&i_mark->fsn_mark); + } + spin_unlock(idr_lock); + } while (ret == -EAGAIN); + + return ret; +} + +static struct inotify_inode_mark *inotify_idr_find_locked(struct fsnotify_group *group, + int wd) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *i_mark; + + assert_spin_locked(idr_lock); + + i_mark = idr_find(idr, wd); + if (i_mark) { + struct fsnotify_mark *fsn_mark = &i_mark->fsn_mark; + + fsnotify_get_mark(fsn_mark); + /* One ref for being in the idr, one ref we just took */ + BUG_ON(atomic_read(&fsn_mark->refcnt) < 2); + } + + return i_mark; +} + +static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group, + int wd) +{ + struct inotify_inode_mark *i_mark; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + + spin_lock(idr_lock); + i_mark = inotify_idr_find_locked(group, wd); + spin_unlock(idr_lock); + + return i_mark; +} + +static void do_inotify_remove_from_idr(struct fsnotify_group *group, + struct inotify_inode_mark *i_mark) +{ + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + int wd = i_mark->wd; + + assert_spin_locked(idr_lock); + + idr_remove(idr, wd); + + /* removed from the idr, drop that ref */ + fsnotify_put_mark(&i_mark->fsn_mark); +} + /* * Remove the mark from the idr (if present) and drop the reference * on the mark because it was in the idr. */ static void inotify_remove_from_idr(struct fsnotify_group *group, - struct inotify_inode_mark_entry *ientry) + struct inotify_inode_mark *i_mark) { - struct idr *idr; - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *found_ientry; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; + struct inotify_inode_mark *found_i_mark = NULL; int wd; - spin_lock(&group->inotify_data.idr_lock); - idr = &group->inotify_data.idr; - wd = ientry->wd; + spin_lock(idr_lock); + wd = i_mark->wd; - if (wd == -1) + /* + * does this i_mark think it is in the idr? we shouldn't get called + * if it wasn't.... + */ + if (wd == -1) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); goto out; + } - entry = idr_find(&group->inotify_data.idr, wd); - if (unlikely(!entry)) + /* Lets look in the idr to see if we find it */ + found_i_mark = inotify_idr_find_locked(group, wd); + if (unlikely(!found_i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); goto out; + } - found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); - if (unlikely(found_ientry != ientry)) { - /* We found an entry in the idr with the right wd, but it's - * not the entry we were told to remove. eparis seriously - * fucked up somewhere. */ - WARN_ON(1); - ientry->wd = -1; + /* + * We found an mark in the idr at the right wd, but it's + * not the mark we were told to remove. eparis seriously + * fucked up somewhere. + */ + if (unlikely(found_i_mark != i_mark)) { + WARN_ONCE(1, "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p " + "mark->inode=%p found_i_mark=%p found_i_mark->wd=%d " + "found_i_mark->group=%p found_i_mark->inode=%p\n", + __func__, i_mark, i_mark->wd, i_mark->fsn_mark.group, + i_mark->fsn_mark.i.inode, found_i_mark, found_i_mark->wd, + found_i_mark->fsn_mark.group, + found_i_mark->fsn_mark.i.inode); goto out; } - /* One ref for being in the idr, one ref held by the caller */ - BUG_ON(atomic_read(&entry->refcnt) < 2); - - idr_remove(idr, wd); - ientry->wd = -1; + /* + * One ref for being in the idr + * one ref held by the caller trying to kill us + * one ref grabbed by inotify_idr_find + */ + if (unlikely(atomic_read(&i_mark->fsn_mark.refcnt) < 3)) { + printk(KERN_ERR "%s: i_mark=%p i_mark->wd=%d i_mark->group=%p" + " i_mark->inode=%p\n", __func__, i_mark, i_mark->wd, + i_mark->fsn_mark.group, i_mark->fsn_mark.i.inode); + /* we can't really recover with bad ref cnting.. */ + BUG(); + } - /* removed from the idr, drop that ref */ - fsnotify_put_mark(entry); + do_inotify_remove_from_idr(group, i_mark); out: - spin_unlock(&group->inotify_data.idr_lock); + /* match the ref taken by inotify_idr_find_locked() */ + if (found_i_mark) + fsnotify_put_mark(&found_i_mark->fsn_mark); + i_mark->wd = -1; + spin_unlock(idr_lock); } /* * Send IN_IGNORED for this wd, remove this wd from the idr. */ -void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, +void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) { - struct inotify_inode_mark_entry *ientry; - struct fsnotify_event *ignored_event; + struct inotify_inode_mark *i_mark; + struct fsnotify_event *ignored_event, *notify_event; struct inotify_event_private_data *event_priv; struct fsnotify_event_private_data *fsn_event_priv; int ret; @@ -420,7 +527,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, if (!ignored_event) return; - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS); if (unlikely(!event_priv)) @@ -429,37 +536,44 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, fsn_event_priv = &event_priv->fsnotify_event_priv_data; fsn_event_priv->group = group; - event_priv->wd = ientry->wd; - - ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); - if (ret) + event_priv->wd = i_mark->wd; + + notify_event = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL); + if (notify_event) { + if (IS_ERR(notify_event)) + ret = PTR_ERR(notify_event); + else + fsnotify_put_event(notify_event); inotify_free_event_priv(fsn_event_priv); + } skip_send_ignore: /* matches the reference taken when the event was created */ fsnotify_put_event(ignored_event); - /* remove this entry from the idr */ - inotify_remove_from_idr(group, ientry); + /* remove this mark from the idr */ + inotify_remove_from_idr(group, i_mark); atomic_dec(&group->inotify_data.user->inotify_watches); } /* ding dong the mark is dead */ -static void inotify_free_mark(struct fsnotify_mark_entry *entry) +static void inotify_free_mark(struct fsnotify_mark *fsn_mark) { - struct inotify_inode_mark_entry *ientry = (struct inotify_inode_mark_entry *)entry; + struct inotify_inode_mark *i_mark; + + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); - kmem_cache_free(inotify_inode_mark_cachep, ientry); + kmem_cache_free(inotify_inode_mark_cachep, i_mark); } static int inotify_update_existing_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) { - struct fsnotify_mark_entry *entry; - struct inotify_inode_mark_entry *ientry; + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; __u32 old_mask, new_mask; __u32 mask; int add = (arg & IN_MASK_ADD); @@ -467,52 +581,43 @@ static int inotify_update_existing_watch(struct fsnotify_group *group, /* don't allow invalid bits: we don't want flags set */ mask = inotify_arg_to_mask(arg); - if (unlikely(!mask)) + if (unlikely(!(mask & IN_ALL_EVENTS))) return -EINVAL; - spin_lock(&inode->i_lock); - entry = fsnotify_find_mark_entry(group, inode); - spin_unlock(&inode->i_lock); - if (!entry) + fsn_mark = fsnotify_find_inode_mark(group, inode); + if (!fsn_mark) return -ENOENT; - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); - spin_lock(&entry->lock); + spin_lock(&fsn_mark->lock); - old_mask = entry->mask; - if (add) { - entry->mask |= mask; - new_mask = entry->mask; - } else { - entry->mask = mask; - new_mask = entry->mask; - } + old_mask = fsn_mark->mask; + if (add) + fsnotify_set_mark_mask_locked(fsn_mark, (fsn_mark->mask | mask)); + else + fsnotify_set_mark_mask_locked(fsn_mark, mask); + new_mask = fsn_mark->mask; - spin_unlock(&entry->lock); + spin_unlock(&fsn_mark->lock); if (old_mask != new_mask) { /* more bits in old than in new? */ int dropped = (old_mask & ~new_mask); - /* more bits in this entry than the inode's mask? */ + /* more bits in this fsn_mark than the inode's mask? */ int do_inode = (new_mask & ~inode->i_fsnotify_mask); - /* more bits in this entry than the group? */ - int do_group = (new_mask & ~group->mask); - /* update the inode with this new entry */ + /* update the inode with this new fsn_mark */ if (dropped || do_inode) fsnotify_recalc_inode_mask(inode); - /* update the group mask with the new mask */ - if (dropped || do_group) - fsnotify_recalc_group_mask(group); } /* return the wd */ - ret = ientry->wd; + ret = i_mark->wd; - /* match the get from fsnotify_find_mark_entry() */ - fsnotify_put_mark(entry); + /* match the get from fsnotify_find_mark() */ + fsnotify_put_mark(fsn_mark); return ret; } @@ -521,73 +626,51 @@ static int inotify_new_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) { - struct inotify_inode_mark_entry *tmp_ientry; + struct inotify_inode_mark *tmp_i_mark; __u32 mask; int ret; + struct idr *idr = &group->inotify_data.idr; + spinlock_t *idr_lock = &group->inotify_data.idr_lock; /* don't allow invalid bits: we don't want flags set */ mask = inotify_arg_to_mask(arg); - if (unlikely(!mask)) + if (unlikely(!(mask & IN_ALL_EVENTS))) return -EINVAL; - tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); - if (unlikely(!tmp_ientry)) + tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); + if (unlikely(!tmp_i_mark)) return -ENOMEM; - fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark); - tmp_ientry->fsn_entry.mask = mask; - tmp_ientry->wd = -1; + fsnotify_init_mark(&tmp_i_mark->fsn_mark, inotify_free_mark); + tmp_i_mark->fsn_mark.mask = mask; + tmp_i_mark->wd = -1; ret = -ENOSPC; if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) goto out_err; -retry: - ret = -ENOMEM; - if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) - goto out_err; - /* we are putting the mark on the idr, take a reference */ - fsnotify_get_mark(&tmp_ientry->fsn_entry); - - spin_lock(&group->inotify_data.idr_lock); - ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, - group->inotify_data.last_wd+1, - &tmp_ientry->wd); - spin_unlock(&group->inotify_data.idr_lock); - if (ret) { - /* we didn't get on the idr, drop the idr reference */ - fsnotify_put_mark(&tmp_ientry->fsn_entry); - - /* idr was out of memory allocate and try again */ - if (ret == -EAGAIN) - goto retry; + ret = inotify_add_to_idr(idr, idr_lock, &group->inotify_data.last_wd, + tmp_i_mark); + if (ret) goto out_err; - } /* we are on the idr, now get on the inode */ - ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); + ret = fsnotify_add_mark(&tmp_i_mark->fsn_mark, group, inode, NULL, 0); if (ret) { /* we failed to get on the inode, get off the idr */ - inotify_remove_from_idr(group, tmp_ientry); + inotify_remove_from_idr(group, tmp_i_mark); goto out_err; } - /* update the idr hint, who cares about races, it's just a hint */ - group->inotify_data.last_wd = tmp_ientry->wd; - /* increment the number of watches the user has */ atomic_inc(&group->inotify_data.user->inotify_watches); - /* return the watch descriptor for this new entry */ - ret = tmp_ientry->wd; - - /* if this mark added a new event update the group mask */ - if (mask & ~group->mask) - fsnotify_recalc_group_mask(group); + /* return the watch descriptor for this new mark */ + ret = tmp_i_mark->wd; out_err: - /* match the ref from fsnotify_init_markentry() */ - fsnotify_put_mark(&tmp_ientry->fsn_entry); + /* match the ref from fsnotify_init_mark() */ + fsnotify_put_mark(&tmp_i_mark->fsn_mark); return ret; } @@ -616,11 +699,8 @@ retry: static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events) { struct fsnotify_group *group; - unsigned int grp_num; - /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */ - grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num)); - group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops); + group = fsnotify_alloc_group(&inotify_fsnotify_ops); if (IS_ERR(group)) return group; @@ -726,7 +806,7 @@ fput_and_out: SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) { struct fsnotify_group *group; - struct fsnotify_mark_entry *entry; + struct inotify_inode_mark *i_mark; struct file *filp; int ret = 0, fput_needed; @@ -735,25 +815,23 @@ SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd) return -EBADF; /* verify that this is indeed an inotify instance */ - if (unlikely(filp->f_op != &inotify_fops)) { - ret = -EINVAL; + ret = -EINVAL; + if (unlikely(filp->f_op != &inotify_fops)) goto out; - } group = filp->private_data; - spin_lock(&group->inotify_data.idr_lock); - entry = idr_find(&group->inotify_data.idr, wd); - if (unlikely(!entry)) { - spin_unlock(&group->inotify_data.idr_lock); - ret = -EINVAL; + ret = -EINVAL; + i_mark = inotify_idr_find(group, wd); + if (unlikely(!i_mark)) goto out; - } - fsnotify_get_mark(entry); - spin_unlock(&group->inotify_data.idr_lock); - fsnotify_destroy_mark_by_entry(entry); - fsnotify_put_mark(entry); + ret = 0; + + fsnotify_destroy_mark(&i_mark->fsn_mark); + + /* match ref taken by inotify_idr_find */ + fsnotify_put_mark(&i_mark->fsn_mark); out: fput_light(filp, fput_needed); @@ -767,7 +845,28 @@ out: */ static int __init inotify_user_setup(void) { - inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC); + BUILD_BUG_ON(IN_ACCESS != FS_ACCESS); + BUILD_BUG_ON(IN_MODIFY != FS_MODIFY); + BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB); + BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE); + BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); + BUILD_BUG_ON(IN_OPEN != FS_OPEN); + BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM); + BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO); + BUILD_BUG_ON(IN_CREATE != FS_CREATE); + BUILD_BUG_ON(IN_DELETE != FS_DELETE); + BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF); + BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF); + BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT); + BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW); + BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED); + BUILD_BUG_ON(IN_EXCL_UNLINK != FS_EXCL_UNLINK); + BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR); + BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT); + + BUG_ON(hweight32(ALL_INOTIFY_BITS) != 21); + + inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark, SLAB_PANIC); event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); inotify_max_queued_events = 16384; diff --git a/fs/notify/mark.c b/fs/notify/mark.c new file mode 100644 index 000000000000..325185e514bb --- /dev/null +++ b/fs/notify/mark.c @@ -0,0 +1,371 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/* + * fsnotify inode mark locking/lifetime/and refcnting + * + * REFCNT: + * The mark->refcnt tells how many "things" in the kernel currently are + * referencing this object. The object typically will live inside the kernel + * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task + * which can find this object holding the appropriete locks, can take a reference + * and the object itself is guarenteed to survive until the reference is dropped. + * + * LOCKING: + * There are 3 spinlocks involved with fsnotify inode marks and they MUST + * be taken in order as follows: + * + * mark->lock + * group->mark_lock + * inode->i_lock + * + * mark->lock protects 2 things, mark->group and mark->inode. You must hold + * that lock to dereference either of these things (they could be NULL even with + * the lock) + * + * group->mark_lock protects the marks_list anchored inside a given group + * and each mark is hooked via the g_list. It also sorta protects the + * free_g_list, which when used is anchored by a private list on the stack of the + * task which held the group->mark_lock. + * + * inode->i_lock protects the i_fsnotify_marks list anchored inside a + * given inode and each mark is hooked via the i_list. (and sorta the + * free_i_list) + * + * + * LIFETIME: + * Inode marks survive between when they are added to an inode and when their + * refcnt==0. + * + * The inode mark can be cleared for a number of different reasons including: + * - The inode is unlinked for the last time. (fsnotify_inode_remove) + * - The inode is being evicted from cache. (fsnotify_inode_delete) + * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) + * - Something explicitly requests that it be removed. (fsnotify_destroy_mark) + * - The fsnotify_group associated with the mark is going away and all such marks + * need to be cleaned up. (fsnotify_clear_marks_by_group) + * + * Worst case we are given an inode and need to clean up all the marks on that + * inode. We take i_lock and walk the i_fsnotify_marks safely. For each + * mark on the list we take a reference (so the mark can't disappear under us). + * We remove that mark form the inode's list of marks and we add this mark to a + * private list anchored on the stack using i_free_list; At this point we no + * longer fear anything finding the mark using the inode's list of marks. + * + * We can safely and locklessly run the private list on the stack of everything + * we just unattached from the original inode. For each mark on the private list + * we grab the mark-> and can thus dereference mark->group and mark->inode. If + * we see the group and inode are not NULL we take those locks. Now holding all + * 3 locks we can completely remove the mark from other tasks finding it in the + * future. Remember, 10 things might already be referencing this mark, but they + * better be holding a ref. We drop our reference we took before we unhooked it + * from the inode. When the ref hits 0 we can free the mark. + * + * Very similarly for freeing by group, except we use free_g_list. + * + * This has the very interesting property of being able to run concurrently with + * any (or all) other directions. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/srcu.h> +#include <linux/writeback.h> /* for inode_lock */ + +#include <asm/atomic.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" + +struct srcu_struct fsnotify_mark_srcu; +static DEFINE_SPINLOCK(destroy_lock); +static LIST_HEAD(destroy_list); +static DECLARE_WAIT_QUEUE_HEAD(destroy_waitq); + +void fsnotify_get_mark(struct fsnotify_mark *mark) +{ + atomic_inc(&mark->refcnt); +} + +void fsnotify_put_mark(struct fsnotify_mark *mark) +{ + if (atomic_dec_and_test(&mark->refcnt)) + mark->free_mark(mark); +} + +/* + * Any time a mark is getting freed we end up here. + * The caller had better be holding a reference to this mark so we don't actually + * do the final put under the mark->lock + */ +void fsnotify_destroy_mark(struct fsnotify_mark *mark) +{ + struct fsnotify_group *group; + struct inode *inode = NULL; + + spin_lock(&mark->lock); + + group = mark->group; + + /* something else already called this function on this mark */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + spin_unlock(&mark->lock); + return; + } + + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + + /* 1 from caller and 1 for being on i_list/g_list */ + BUG_ON(atomic_read(&mark->refcnt) < 2); + + spin_lock(&group->mark_lock); + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { + inode = mark->i.inode; + fsnotify_destroy_inode_mark(mark); + } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT) + fsnotify_destroy_vfsmount_mark(mark); + else + BUG(); + + list_del_init(&mark->g_list); + + spin_unlock(&group->mark_lock); + spin_unlock(&mark->lock); + + spin_lock(&destroy_lock); + list_add(&mark->destroy_list, &destroy_list); + spin_unlock(&destroy_lock); + wake_up(&destroy_waitq); + + /* + * Some groups like to know that marks are being freed. This is a + * callback to the group function to let it know that this mark + * is being freed. + */ + if (group->ops->freeing_mark) + group->ops->freeing_mark(mark, group); + + /* + * __fsnotify_update_child_dentry_flags(inode); + * + * I really want to call that, but we can't, we have no idea if the inode + * still exists the second we drop the mark->lock. + * + * The next time an event arrive to this inode from one of it's children + * __fsnotify_parent will see that the inode doesn't care about it's + * children and will update all of these flags then. So really this + * is just a lazy update (and could be a perf win...) + */ + + if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) + iput(inode); + + /* + * it's possible that this group tried to destroy itself, but this + * this mark was simultaneously being freed by inode. If that's the + * case, we finish freeing the group here. + */ + if (unlikely(atomic_dec_and_test(&group->num_marks))) + fsnotify_final_destroy_group(group); +} + +void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask) +{ + assert_spin_locked(&mark->lock); + + mark->mask = mask; + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) + fsnotify_set_inode_mark_mask_locked(mark, mask); +} + +void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask) +{ + assert_spin_locked(&mark->lock); + + mark->ignored_mask = mask; +} + +/* + * Attach an initialized mark to a given group and fs object. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which group. + */ +int fsnotify_add_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + struct vfsmount *mnt, int allow_dups) +{ + int ret = 0; + + BUG_ON(inode && mnt); + BUG_ON(!inode && !mnt); + + /* + * LOCKING ORDER!!!! + * mark->lock + * group->mark_lock + * inode->i_lock + */ + spin_lock(&mark->lock); + spin_lock(&group->mark_lock); + + mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE; + + mark->group = group; + list_add(&mark->g_list, &group->marks_list); + atomic_inc(&group->num_marks); + fsnotify_get_mark(mark); /* for i_list and g_list */ + + if (inode) { + ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups); + if (ret) + goto err; + } else if (mnt) { + ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups); + if (ret) + goto err; + } else { + BUG(); + } + + spin_unlock(&group->mark_lock); + + /* this will pin the object if appropriate */ + fsnotify_set_mark_mask_locked(mark, mark->mask); + + spin_unlock(&mark->lock); + + if (inode) + __fsnotify_update_child_dentry_flags(inode); + + return ret; +err: + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + list_del_init(&mark->g_list); + mark->group = NULL; + atomic_dec(&group->num_marks); + + spin_unlock(&group->mark_lock); + spin_unlock(&mark->lock); + + spin_lock(&destroy_lock); + list_add(&mark->destroy_list, &destroy_list); + spin_unlock(&destroy_lock); + wake_up(&destroy_waitq); + + return ret; +} + +/* + * clear any marks in a group in which mark->flags & flags is true + */ +void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, + unsigned int flags) +{ + struct fsnotify_mark *lmark, *mark; + LIST_HEAD(free_list); + + spin_lock(&group->mark_lock); + list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { + if (mark->flags & flags) { + list_add(&mark->free_g_list, &free_list); + list_del_init(&mark->g_list); + fsnotify_get_mark(mark); + } + } + spin_unlock(&group->mark_lock); + + list_for_each_entry_safe(mark, lmark, &free_list, free_g_list) { + fsnotify_destroy_mark(mark); + fsnotify_put_mark(mark); + } +} + +/* + * Given a group, destroy all of the marks associated with that group. + */ +void fsnotify_clear_marks_by_group(struct fsnotify_group *group) +{ + fsnotify_clear_marks_by_group_flags(group, (unsigned int)-1); +} + +void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) +{ + assert_spin_locked(&old->lock); + new->i.inode = old->i.inode; + new->m.mnt = old->m.mnt; + new->group = old->group; + new->mask = old->mask; + new->free_mark = old->free_mark; +} + +/* + * Nothing fancy, just initialize lists and locks and counters. + */ +void fsnotify_init_mark(struct fsnotify_mark *mark, + void (*free_mark)(struct fsnotify_mark *mark)) +{ + memset(mark, 0, sizeof(*mark)); + spin_lock_init(&mark->lock); + atomic_set(&mark->refcnt, 1); + mark->free_mark = free_mark; +} + +static int fsnotify_mark_destroy(void *ignored) +{ + struct fsnotify_mark *mark, *next; + LIST_HEAD(private_destroy_list); + + for (;;) { + spin_lock(&destroy_lock); + /* exchange the list head */ + list_replace_init(&destroy_list, &private_destroy_list); + spin_unlock(&destroy_lock); + + synchronize_srcu(&fsnotify_mark_srcu); + + list_for_each_entry_safe(mark, next, &private_destroy_list, destroy_list) { + list_del_init(&mark->destroy_list); + fsnotify_put_mark(mark); + } + + wait_event_interruptible(destroy_waitq, !list_empty(&destroy_list)); + } + + return 0; +} + +static int __init fsnotify_mark_init(void) +{ + struct task_struct *thread; + + thread = kthread_run(fsnotify_mark_destroy, NULL, + "fsnotify_mark"); + if (IS_ERR(thread)) + panic("unable to start fsnotify mark destruction thread."); + + return 0; +} +device_initcall(fsnotify_mark_init); diff --git a/fs/notify/notification.c b/fs/notify/notification.c index b8bf53b4c108..f39260f8f865 100644 --- a/fs/notify/notification.c +++ b/fs/notify/notification.c @@ -56,7 +56,7 @@ static struct kmem_cache *fsnotify_event_holder_cachep; * it is needed. It's refcnt is set 1 at kernel init time and will never * get set to 0 so it will never get 'freed' */ -static struct fsnotify_event q_overflow_event; +static struct fsnotify_event *q_overflow_event; static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0); /** @@ -87,12 +87,15 @@ void fsnotify_put_event(struct fsnotify_event *event) return; if (atomic_dec_and_test(&event->refcnt)) { + pr_debug("%s: event=%p\n", __func__, event); + if (event->data_type == FSNOTIFY_EVENT_PATH) path_put(&event->path); BUG_ON(!list_empty(&event->private_data_list)); kfree(event->file_name); + put_pid(event->tgid); kmem_cache_free(fsnotify_event_cachep, event); } } @@ -104,7 +107,8 @@ struct fsnotify_event_holder *fsnotify_alloc_event_holder(void) void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder) { - kmem_cache_free(fsnotify_event_holder_cachep, holder); + if (holder) + kmem_cache_free(fsnotify_event_holder_cachep, holder); } /* @@ -129,53 +133,20 @@ struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnot } /* - * Check if 2 events contain the same information. We do not compare private data - * but at this moment that isn't a problem for any know fsnotify listeners. - */ -static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new) -{ - if ((old->mask == new->mask) && - (old->to_tell == new->to_tell) && - (old->data_type == new->data_type) && - (old->name_len == new->name_len)) { - switch (old->data_type) { - case (FSNOTIFY_EVENT_INODE): - /* remember, after old was put on the wait_q we aren't - * allowed to look at the inode any more, only thing - * left to check was if the file_name is the same */ - if (!old->name_len || - !strcmp(old->file_name, new->file_name)) - return true; - break; - case (FSNOTIFY_EVENT_PATH): - if ((old->path.mnt == new->path.mnt) && - (old->path.dentry == new->path.dentry)) - return true; - break; - case (FSNOTIFY_EVENT_NONE): - if (old->mask & FS_Q_OVERFLOW) - return true; - else if (old->mask & FS_IN_IGNORED) - return false; - return false; - }; - } - return false; -} - -/* * Add an event to the group notification queue. The group can later pull this * event off the queue to deal with. If the event is successfully added to the * group's notification queue, a reference is taken on event. */ -int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event, - struct fsnotify_event_private_data *priv) +struct fsnotify_event *fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event, + struct fsnotify_event_private_data *priv, + struct fsnotify_event *(*merge)(struct list_head *, + struct fsnotify_event *)) { + struct fsnotify_event *return_event = NULL; struct fsnotify_event_holder *holder = NULL; struct list_head *list = &group->notification_list; - struct fsnotify_event_holder *last_holder; - struct fsnotify_event *last_event; - int ret = 0; + + pr_debug("%s: group=%p event=%p priv=%p\n", __func__, group, event, priv); /* * There is one fsnotify_event_holder embedded inside each fsnotify_event. @@ -189,18 +160,40 @@ int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_even alloc_holder: holder = fsnotify_alloc_event_holder(); if (!holder) - return -ENOMEM; + return ERR_PTR(-ENOMEM); } mutex_lock(&group->notification_mutex); if (group->q_len >= group->max_events) { - event = &q_overflow_event; - ret = -EOVERFLOW; + event = q_overflow_event; + + /* + * we need to return the overflow event + * which means we need a ref + */ + fsnotify_get_event(event); + return_event = event; + /* sorry, no private data on the overflow event */ priv = NULL; } + if (!list_empty(list) && merge) { + struct fsnotify_event *tmp; + + tmp = merge(list, event); + if (tmp) { + mutex_unlock(&group->notification_mutex); + + if (return_event) + fsnotify_put_event(return_event); + if (holder != &event->holder) + fsnotify_destroy_event_holder(holder); + return tmp; + } + } + spin_lock(&event->lock); if (list_empty(&event->holder.event_list)) { @@ -212,19 +205,13 @@ alloc_holder: * event holder was used, go back and get a new one */ spin_unlock(&event->lock); mutex_unlock(&group->notification_mutex); - goto alloc_holder; - } - if (!list_empty(list)) { - last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list); - last_event = last_holder->event; - if (event_compare(last_event, event)) { - spin_unlock(&event->lock); - mutex_unlock(&group->notification_mutex); - if (holder != &event->holder) - fsnotify_destroy_event_holder(holder); - return -EEXIST; + if (return_event) { + fsnotify_put_event(return_event); + return_event = NULL; } + + goto alloc_holder; } group->q_len++; @@ -238,7 +225,7 @@ alloc_holder: mutex_unlock(&group->notification_mutex); wake_up(&group->notification_waitq); - return ret; + return return_event; } /* @@ -253,6 +240,8 @@ struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group BUG_ON(!mutex_is_locked(&group->notification_mutex)); + pr_debug("%s: group=%p\n", __func__, group); + holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list); event = holder->event; @@ -314,25 +303,82 @@ void fsnotify_flush_notify(struct fsnotify_group *group) static void initialize_event(struct fsnotify_event *event) { - event->holder.event = NULL; INIT_LIST_HEAD(&event->holder.event_list); atomic_set(&event->refcnt, 1); spin_lock_init(&event->lock); - event->path.dentry = NULL; - event->path.mnt = NULL; - event->inode = NULL; - event->data_type = FSNOTIFY_EVENT_NONE; - INIT_LIST_HEAD(&event->private_data_list); +} + +/* + * Caller damn well better be holding whatever mutex is protecting the + * old_holder->event_list and the new_event must be a clean event which + * cannot be found anywhere else in the kernel. + */ +int fsnotify_replace_event(struct fsnotify_event_holder *old_holder, + struct fsnotify_event *new_event) +{ + struct fsnotify_event *old_event = old_holder->event; + struct fsnotify_event_holder *new_holder = &new_event->holder; - event->to_tell = NULL; + enum event_spinlock_class { + SPINLOCK_OLD, + SPINLOCK_NEW, + }; - event->file_name = NULL; - event->name_len = 0; + pr_debug("%s: old_event=%p new_event=%p\n", __func__, old_event, new_event); - event->sync_cookie = 0; + /* + * if the new_event's embedded holder is in use someone + * screwed up and didn't give us a clean new event. + */ + BUG_ON(!list_empty(&new_holder->event_list)); + + spin_lock_nested(&old_event->lock, SPINLOCK_OLD); + spin_lock_nested(&new_event->lock, SPINLOCK_NEW); + + new_holder->event = new_event; + list_replace_init(&old_holder->event_list, &new_holder->event_list); + + spin_unlock(&new_event->lock); + spin_unlock(&old_event->lock); + + /* event == holder means we are referenced through the in event holder */ + if (old_holder != &old_event->holder) + fsnotify_destroy_event_holder(old_holder); + + fsnotify_get_event(new_event); /* on the list take reference */ + fsnotify_put_event(old_event); /* off the list, drop reference */ + + return 0; +} + +struct fsnotify_event *fsnotify_clone_event(struct fsnotify_event *old_event) +{ + struct fsnotify_event *event; + + event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL); + if (!event) + return NULL; + + pr_debug("%s: old_event=%p new_event=%p\n", __func__, old_event, event); + + memcpy(event, old_event, sizeof(*event)); + initialize_event(event); + + if (event->name_len) { + event->file_name = kstrdup(old_event->file_name, GFP_KERNEL); + if (!event->file_name) { + kmem_cache_free(fsnotify_event_cachep, event); + return NULL; + } + } + event->tgid = get_pid(old_event->tgid); + if (event->data_type == FSNOTIFY_EVENT_PATH) + path_get(&event->path); + + return event; } /* @@ -348,15 +394,18 @@ static void initialize_event(struct fsnotify_event *event) * @name the filename, if available */ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data, - int data_type, const char *name, u32 cookie, - gfp_t gfp) + int data_type, const unsigned char *name, + u32 cookie, gfp_t gfp) { struct fsnotify_event *event; - event = kmem_cache_alloc(fsnotify_event_cachep, gfp); + event = kmem_cache_zalloc(fsnotify_event_cachep, gfp); if (!event) return NULL; + pr_debug("%s: event=%p to_tell=%p mask=%x data=%p data_type=%d\n", + __func__, event, to_tell, mask, data, data_type); + initialize_event(event); if (name) { @@ -368,30 +417,21 @@ struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, event->name_len = strlen(event->file_name); } + event->tgid = get_pid(task_tgid(current)); event->sync_cookie = cookie; event->to_tell = to_tell; + event->data_type = data_type; switch (data_type) { - case FSNOTIFY_EVENT_FILE: { - struct file *file = data; - struct path *path = &file->f_path; - event->path.dentry = path->dentry; - event->path.mnt = path->mnt; - path_get(&event->path); - event->data_type = FSNOTIFY_EVENT_PATH; - break; - } case FSNOTIFY_EVENT_PATH: { struct path *path = data; event->path.dentry = path->dentry; event->path.mnt = path->mnt; path_get(&event->path); - event->data_type = FSNOTIFY_EVENT_PATH; break; } case FSNOTIFY_EVENT_INODE: event->inode = data; - event->data_type = FSNOTIFY_EVENT_INODE; break; case FSNOTIFY_EVENT_NONE: event->inode = NULL; @@ -412,8 +452,11 @@ __init int fsnotify_notification_init(void) fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC); fsnotify_event_holder_cachep = KMEM_CACHE(fsnotify_event_holder, SLAB_PANIC); - initialize_event(&q_overflow_event); - q_overflow_event.mask = FS_Q_OVERFLOW; + q_overflow_event = fsnotify_create_event(NULL, FS_Q_OVERFLOW, NULL, + FSNOTIFY_EVENT_NONE, NULL, 0, + GFP_KERNEL); + if (!q_overflow_event) + panic("unable to allocate fsnotify q_overflow_event\n"); return 0; } diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c new file mode 100644 index 000000000000..56772b578fbd --- /dev/null +++ b/fs/notify/vfsmount_mark.c @@ -0,0 +1,187 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mount.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/writeback.h> /* for inode_lock */ + +#include <asm/atomic.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" + +void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) +{ + struct fsnotify_mark *mark, *lmark; + struct hlist_node *pos, *n; + LIST_HEAD(free_list); + + spin_lock(&mnt->mnt_root->d_lock); + hlist_for_each_entry_safe(mark, pos, n, &mnt->mnt_fsnotify_marks, m.m_list) { + list_add(&mark->m.free_m_list, &free_list); + hlist_del_init_rcu(&mark->m.m_list); + fsnotify_get_mark(mark); + } + spin_unlock(&mnt->mnt_root->d_lock); + + list_for_each_entry_safe(mark, lmark, &free_list, m.free_m_list) { + fsnotify_destroy_mark(mark); + fsnotify_put_mark(mark); + } +} + +void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) +{ + fsnotify_clear_marks_by_group_flags(group, FSNOTIFY_MARK_FLAG_VFSMOUNT); +} + +/* + * Recalculate the mask of events relevant to a given vfsmount locked. + */ +static void fsnotify_recalc_vfsmount_mask_locked(struct vfsmount *mnt) +{ + struct fsnotify_mark *mark; + struct hlist_node *pos; + __u32 new_mask = 0; + + assert_spin_locked(&mnt->mnt_root->d_lock); + + hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) + new_mask |= mark->mask; + mnt->mnt_fsnotify_mask = new_mask; +} + +/* + * Recalculate the mnt->mnt_fsnotify_mask, or the mask of all FS_* event types + * any notifier is interested in hearing for this mount point + */ +void fsnotify_recalc_vfsmount_mask(struct vfsmount *mnt) +{ + spin_lock(&mnt->mnt_root->d_lock); + fsnotify_recalc_vfsmount_mask_locked(mnt); + spin_unlock(&mnt->mnt_root->d_lock); +} + +void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark) +{ + struct vfsmount *mnt = mark->m.mnt; + + assert_spin_locked(&mark->lock); + assert_spin_locked(&mark->group->mark_lock); + + spin_lock(&mnt->mnt_root->d_lock); + + hlist_del_init_rcu(&mark->m.m_list); + mark->m.mnt = NULL; + + fsnotify_recalc_vfsmount_mask_locked(mnt); + + spin_unlock(&mnt->mnt_root->d_lock); +} + +static struct fsnotify_mark *fsnotify_find_vfsmount_mark_locked(struct fsnotify_group *group, + struct vfsmount *mnt) +{ + struct fsnotify_mark *mark; + struct hlist_node *pos; + + assert_spin_locked(&mnt->mnt_root->d_lock); + + hlist_for_each_entry(mark, pos, &mnt->mnt_fsnotify_marks, m.m_list) { + if (mark->group == group) { + fsnotify_get_mark(mark); + return mark; + } + } + return NULL; +} + +/* + * given a group and vfsmount, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL + */ +struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, + struct vfsmount *mnt) +{ + struct fsnotify_mark *mark; + + spin_lock(&mnt->mnt_root->d_lock); + mark = fsnotify_find_vfsmount_mark_locked(group, mnt); + spin_unlock(&mnt->mnt_root->d_lock); + + return mark; +} + +/* + * Attach an initialized mark to a given group and vfsmount. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which groups. + */ +int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct vfsmount *mnt, + int allow_dups) +{ + struct fsnotify_mark *lmark; + struct hlist_node *node, *last = NULL; + int ret = 0; + + mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT; + + assert_spin_locked(&mark->lock); + assert_spin_locked(&group->mark_lock); + + spin_lock(&mnt->mnt_root->d_lock); + + mark->m.mnt = mnt; + + /* is mark the first mark? */ + if (hlist_empty(&mnt->mnt_fsnotify_marks)) { + hlist_add_head_rcu(&mark->m.m_list, &mnt->mnt_fsnotify_marks); + goto out; + } + + /* should mark be in the middle of the current list? */ + hlist_for_each_entry(lmark, node, &mnt->mnt_fsnotify_marks, m.m_list) { + last = node; + + if ((lmark->group == group) && !allow_dups) { + ret = -EEXIST; + goto out; + } + + if (mark->group < lmark->group) + continue; + + hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list); + goto out; + } + + BUG_ON(last == NULL); + /* mark should be the last entry. last is the current last entry */ + hlist_add_after_rcu(last, &mark->m.m_list); +out: + fsnotify_recalc_vfsmount_mask_locked(mnt); + spin_unlock(&mnt->mnt_root->d_lock); + + return ret; +} |