The special overflow event is allocated as struct fanotify_path_event,
but with a null path.
Use a special event type to identify the overflow event, so the helper
fanotify_has_event_path() will always indicate a non null path.
Allocating the overflow event doesn't need any of the fancy stuff in
fanotify_alloc_event(), so create a simplified helper for allocating the
overflow event.
There is also no need to store and report the pid with an overflow event.
Suggested-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 27 +++++++++++----------------
fs/notify/fanotify/fanotify.h | 15 +++++++++------
fs/notify/fanotify/fanotify_user.c | 21 ++++++++++++++++-----
3 files changed, 36 insertions(+), 27 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index d9fc83dd994a..921ff05e1877 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -344,11 +344,11 @@ static struct inode *fanotify_fid_inode(struct inode *to_tell, u32 event_mask,
return fsnotify_data_inode(data, data_type);
}
-struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
- struct inode *inode, u32 mask,
- const void *data, int data_type,
- const struct qstr *file_name,
- __kernel_fsid_t *fsid)
+static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
+ struct inode *inode, u32 mask,
+ const void *data, int data_type,
+ const struct qstr *file_name,
+ __kernel_fsid_t *fsid)
{
struct fanotify_event *event = NULL;
struct fanotify_fid_event *ffe = NULL;
@@ -426,8 +426,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
* event queue, so event reported on parent is merged with event
* reported on child when both directory and child watches exist.
*/
- fsnotify_init_event(&event->fse, (unsigned long)id);
- event->mask = mask;
+ fanotify_init_event(event, (unsigned long)id, mask);
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
event->pid = get_pid(task_pid(current));
else
@@ -443,15 +442,8 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
fanotify_encode_fh(fanotify_event_dir_fh(event), id, gfp);
if (fanotify_event_has_path(event)) {
- struct path *p = fanotify_event_path(event);
-
- if (path) {
- *p = *path;
- path_get(path);
- } else {
- p->mnt = NULL;
- p->dentry = NULL;
- }
+ *fanotify_event_path(event) = *path;
+ path_get(path);
}
out:
memalloc_unuse_memcg();
@@ -640,6 +632,9 @@ static void fanotify_free_event(struct fsnotify_event *fsn_event)
case FANOTIFY_EVENT_TYPE_FID_NAME:
fanotify_free_name_event(event);
break;
+ case FANOTIFY_EVENT_TYPE_OVERFLOW:
+ kfree(event);
+ break;
default:
WARN_ON_ONCE(1);
}
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 8ce7ccfc4b0d..1b2a3bbe6008 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -63,6 +63,7 @@ enum fanotify_event_type {
FANOTIFY_EVENT_TYPE_FID_NAME, /* variable length */
FANOTIFY_EVENT_TYPE_PATH,
FANOTIFY_EVENT_TYPE_PATH_PERM,
+ FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */
};
struct fanotify_event {
@@ -72,6 +73,14 @@ struct fanotify_event {
struct pid *pid;
};
+static inline void fanotify_init_event(struct fanotify_event *event,
+ unsigned long id, u32 mask)
+{
+ fsnotify_init_event(&event->fse, id);
+ event->mask = mask;
+ event->pid = NULL;
+}
+
struct fanotify_fid_event {
struct fanotify_event fae;
__kernel_fsid_t fsid;
@@ -202,9 +211,3 @@ static inline struct path *fanotify_event_path(struct fanotify_event *event)
else
return NULL;
}
-
-struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
- struct inode *inode, u32 mask,
- const void *data, int data_type,
- const struct qstr *file_name,
- __kernel_fsid_t *fsid);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 63b5dffdca9e..8f3c70873598 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -831,13 +831,26 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
FSNOTIFY_OBJ_TYPE_INODE, mask, flags, fsid);
}
+static struct fsnotify_event *fanotify_alloc_overflow_event(void)
+{
+ struct fanotify_event *oevent;
+
+ oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT);
+ if (!oevent)
+ return NULL;
+
+ fanotify_init_event(oevent, 0, FS_Q_OVERFLOW);
+ oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW;
+
+ return &oevent->fse;
+}
+
/* fanotify syscalls */
SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
{
struct fsnotify_group *group;
int f_flags, fd;
struct user_struct *user;
- struct fanotify_event *oevent;
pr_debug("%s: flags=%x event_f_flags=%x\n",
__func__, flags, event_f_flags);
@@ -892,13 +905,11 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
atomic_inc(&user->fanotify_listeners);
group->memcg = get_mem_cgroup_from_mm(current->mm);
- oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL,
- FSNOTIFY_EVENT_NONE, NULL, NULL);
- if (unlikely(!oevent)) {
+ group->overflow_event = fanotify_alloc_overflow_event();
+ if (unlikely(!group->overflow_event)) {
fd = -ENOMEM;
goto out_destroy_group;
}
- group->overflow_event = &oevent->fse;
if (force_o_largefile())
event_f_flags |= O_LARGEFILE;
--
2.17.1
