* allocated and used.
*/
+#include <linux/file.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
* 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);
/**
return;
if (atomic_dec_and_test(&event->refcnt)) {
- if (event->data_type == FSNOTIFY_EVENT_PATH)
- path_put(&event->path);
+ pr_debug("%s: event=%p\n", __func__, event);
+
+ if (event->data_type == FSNOTIFY_EVENT_FILE)
+ fput(event->file);
BUG_ON(!list_empty(&event->private_data_list));
kfree(event->file_name);
+ put_pid(event->tgid);
kmem_cache_free(fsnotify_event_cachep, event);
}
}
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);
}
/*
return priv;
}
-/*
- * 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.
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)) {
* 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++;
mutex_unlock(&group->notification_mutex);
wake_up(&group->notification_waitq);
- return ret;
+ return return_event;
}
/*
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;
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;
+
+ enum event_spinlock_class {
+ SPINLOCK_OLD,
+ SPINLOCK_NEW,
+ };
- event->to_tell = NULL;
+ pr_debug("%s: old_event=%p new_event=%p\n", __func__, old_event, new_event);
- event->file_name = NULL;
- event->name_len = 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));
- event->sync_cookie = 0;
+ 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_FILE)
+ get_file(event->file);
+
+ return 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) {
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;
+ event->file = data;
+ get_file(event->file);
break;
}
case FSNOTIFY_EVENT_INODE:
event->inode = data;
- event->data_type = FSNOTIFY_EVENT_INODE;
break;
case FSNOTIFY_EVENT_NONE:
event->inode = NULL;
- event->path.dentry = NULL;
- event->path.mnt = NULL;
+ event->file = NULL;
break;
default:
BUG();
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;
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff