Fanotify code has an own lock (access_lock) to protect a list of events
waiting for a response from userspace. However this is somewhat awkward
as the same list_head in the event is protected by notification_lock
if it is part of the notification queue and by access_lock if it is part
of the fanotify private queue which makes it difficult for any reliable
checks in the generic code. So make fanotify use the same lock -
notification_lock - for protecting its private event list.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 13 +++++--------
include/linux/fsnotify_backend.h | 1 -
2 files changed, 5 insertions(+), 9 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index e6f3fe9bb2ed..aed06fe2533d 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -147,7 +147,7 @@ static struct fanotify_perm_event_info *dequeue_event(
{
struct fanotify_perm_event_info *event, *return_e = NULL;
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_for_each_entry(event, &group->fanotify_data.access_list,
fae.fse.list) {
if (event->fd != fd)
@@ -157,7 +157,7 @@ static struct fanotify_perm_event_info *dequeue_event(
return_e = event;
break;
}
- spin_unlock(&group->fanotify_data.access_lock);
+ spin_unlock(&group->notification_lock);
pr_debug("%s: found return_re=%p\n", __func__, return_e);
@@ -309,10 +309,10 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
wake_up(&group->fanotify_data.access_waitq);
break;
}
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_add_tail(&kevent->list,
&group->fanotify_data.access_list);
- spin_unlock(&group->fanotify_data.access_lock);
+ spin_unlock(&group->notification_lock);
#endif
}
buf += ret;
@@ -371,7 +371,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
* Process all permission events on access_list and notification queue
* and simulate reply from userspace.
*/
- spin_lock(&group->fanotify_data.access_lock);
+ spin_lock(&group->notification_lock);
list_for_each_entry_safe(event, next, &group->fanotify_data.access_list,
fae.fse.list) {
pr_debug("%s: found group=%p event=%p\n", __func__, group,
@@ -380,14 +380,12 @@ static int fanotify_release(struct inode *ignored, struct file *file)
list_del_init(&event->fae.fse.list);
event->response = FAN_ALLOW;
}
- spin_unlock(&group->fanotify_data.access_lock);
/*
* Destroy all non-permission events. For permission events just
* dequeue them and set the response. They will be freed once the
* response is consumed and fanotify_get_response() returns.
*/
- spin_lock(&group->notification_lock);
while (!fsnotify_notify_queue_is_empty(group)) {
fsn_event = fsnotify_remove_first_event(group);
if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) {
@@ -767,7 +765,6 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
event_f_flags |= O_LARGEFILE;
group->fanotify_data.f_flags = event_f_flags;
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
- spin_lock_init(&group->fanotify_data.access_lock);
init_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list);
#endif
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 0713e873b1c9..79467b239fcf 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -177,7 +177,6 @@ struct fsnotify_group {
struct fanotify_group_private_data {
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
/* allows a group to block waiting for a userspace response */
- spinlock_t access_lock;
struct list_head access_list;
wait_queue_head_t access_waitq;
#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
--
2.6.6
--
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