Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...

[linux.git] / fs / inotify.c

diff --git a/fs/inotify.c b/fs/inotify.c
index f5099d86fd91fba6d3574e804be85a26e2201d68..690e72595e6e6048addba645cf179cb418208f50 100644 (file)
--- a/fs/inotify.c
+++ b/fs/inotify.c
@@ -168,20 +168,14 @@ static void set_dentry_child_flags(struct inode *inode, int watched)
                struct dentry *child;
 
                list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
-                       if (!child->d_inode) {
-                               WARN_ON(child->d_flags & DCACHE_INOTIFY_PARENT_WATCHED);
+                       if (!child->d_inode)
                                continue;
-                       }
+
                        spin_lock(&child->d_lock);
-                       if (watched) {
-                               WARN_ON(child->d_flags &
-                                               DCACHE_INOTIFY_PARENT_WATCHED);
+                       if (watched)
                                child->d_flags |= DCACHE_INOTIFY_PARENT_WATCHED;
-                       } else {
-                               WARN_ON(!(child->d_flags &
-                                       DCACHE_INOTIFY_PARENT_WATCHED));
-                               child->d_flags&=~DCACHE_INOTIFY_PARENT_WATCHED;
-                       }
+                       else
+                               child->d_flags &=~DCACHE_INOTIFY_PARENT_WATCHED;
                        spin_unlock(&child->d_lock);
                }
        }
@@ -253,7 +247,6 @@ void inotify_d_instantiate(struct dentry *entry, struct inode *inode)
        if (!inode)
                return;
 
-       WARN_ON(entry->d_flags & DCACHE_INOTIFY_PARENT_WATCHED);
        spin_lock(&entry->d_lock);
        parent = entry->d_parent;
        if (parent->d_inode && inotify_inode_watched(parent->d_inode))
@@ -509,7 +502,7 @@ void inotify_destroy(struct inotify_handle *ih)
                        mutex_unlock(&ih->mutex);
                        break;
                }
-               watch = list_entry(watches->next, struct inotify_watch, h_list);
+               watch = list_first_entry(watches, struct inotify_watch, h_list);
                get_inotify_watch(watch);
                mutex_unlock(&ih->mutex);
 
@@ -627,6 +620,7 @@ 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;
@@ -653,12 +647,18 @@ s32 inotify_add_watch(struct inotify_handle *ih, struct inotify_watch *watch,
         */
        watch->inode = igrab(inode);
 
-       if (!inotify_inode_watched(inode))
-               set_dentry_child_flags(inode, 1);
-
        /* 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);
@@ -666,6 +666,49 @@ out:
 }
 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