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-rw-r--r--fs/notify/fsnotify.c92
1 files changed, 70 insertions, 22 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 23b5cfbeed50..a61aaa710825 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>
@@ -134,6 +135,45 @@ void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
}
EXPORT_SYMBOL_GPL(__fsnotify_parent);
+static void send_to_group(__u32 mask,
+ struct fsnotify_group *group,
+ void *data, int data_is, const char *file_name,
+ u32 cookie, struct fsnotify_event **event,
+ struct inode *to_tell)
+{
+ if (!group->ops->should_send_event(group, to_tell, mask,
+ data, data_is))
+ return;
+ 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)
+ return;
+ }
+ group->ops->handle_event(group, *event);
+}
+
+static bool needed_by_vfsmount(__u32 test_mask, void *data, int data_is)
+{
+ struct path *path;
+
+ if (data_is == FSNOTIFY_EVENT_PATH)
+ path = (struct path *)data;
+ else if (data_is == FSNOTIFY_EVENT_FILE)
+ path = &((struct file *)data)->f_path;
+ else
+ return false;
+
+ /* hook in this when mnt->mnt_fsnotify_mask is defined */
+ /* return (test_mask & path->mnt->mnt_fsnotify_mask); */
+ return false;
+}
/*
* 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
@@ -148,38 +188,46 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
/* 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_inode_groups))
- return;
+ /* if no fsnotify listeners, nothing to do */
+ if (list_empty(&fsnotify_inode_groups) &&
+ list_empty(&fsnotify_vfsmount_groups))
+ return;
+
+ /* if none of the directed listeners or vfsmount listeners care */
+ if (!(test_mask & fsnotify_inode_mask) &&
+ !(test_mask & fsnotify_vfsmount_mask))
+ return;
+
+ /* if this inode's directed listeners don't care and nothing on the vfsmount
+ * listeners list cares, nothing to do */
+ if (!(test_mask & to_tell->i_fsnotify_mask) &&
+ !needed_by_vfsmount(test_mask, data, data_is))
+ return;
- if (!(test_mask & fsnotify_inode_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.
*/
idx = srcu_read_lock(&fsnotify_grp_srcu);
- list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
- if (test_mask & group->mask) {
- if (!group->ops->should_send_event(group, to_tell, mask,
- data, data_is))
- 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;
+
+ if (test_mask & to_tell->i_fsnotify_mask) {
+ list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
+ if (test_mask & group->mask) {
+ send_to_group(mask, group, data, data_is,
+ file_name, cookie, &event, to_tell);
}
- group->ops->handle_event(group, event);
}
}
+ if (needed_by_vfsmount(test_mask, data, data_is)) {
+ list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list) {
+ if (test_mask & group->mask) {
+ send_to_group(mask, group, data, data_is,
+ file_name, cookie, &event, to_tell);
+ }
+ }
+ }
+
srcu_read_unlock(&fsnotify_grp_srcu, idx);
/*
* fsnotify_create_event() took a reference so the event can't be cleaned