diff options
Diffstat (limited to 'fs/notify/fsnotify.c')
| -rw-r--r-- | fs/notify/fsnotify.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index ff69ae24c4e8..272c8a1dab3c 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -117,17 +117,13 @@ void fsnotify_sb_free(struct super_block *sb) * parent cares. Thus when an event happens on a child it can quickly tell * if there is a need to find a parent and send the event to the parent. */ -void __fsnotify_update_child_dentry_flags(struct inode *inode) +void fsnotify_set_children_dentry_flags(struct inode *inode) { struct dentry *alias; - int watched; if (!S_ISDIR(inode->i_mode)) return; - /* determine if the children should tell inode about their events */ - watched = fsnotify_inode_watches_children(inode); - spin_lock(&inode->i_lock); /* run all of the dentries associated with this inode. Since this is a * directory, there damn well better only be one item on this list */ @@ -143,10 +139,7 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) continue; spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); - if (watched) - child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; - else - child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; + child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; spin_unlock(&child->d_lock); } spin_unlock(&alias->d_lock); @@ -154,6 +147,24 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) spin_unlock(&inode->i_lock); } +/* + * Lazily clear false positive PARENT_WATCHED flag for child whose parent had + * stopped watching children. + */ +static void fsnotify_clear_child_dentry_flag(struct inode *pinode, + struct dentry *dentry) +{ + spin_lock(&dentry->d_lock); + /* + * d_lock is a sufficient barrier to prevent observing a non-watched + * parent state from before the fsnotify_set_children_dentry_flags() + * or fsnotify_update_flags() call that had set PARENT_WATCHED. + */ + if (!fsnotify_inode_watches_children(pinode)) + dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; + spin_unlock(&dentry->d_lock); +} + /* Are inode/sb/mount interested in parent and name info with this event? */ static bool fsnotify_event_needs_parent(struct inode *inode, __u32 mnt_mask, __u32 mask) @@ -228,7 +239,7 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data, p_inode = parent->d_inode; p_mask = fsnotify_inode_watches_children(p_inode); if (unlikely(parent_watched && !p_mask)) - __fsnotify_update_child_dentry_flags(p_inode); + fsnotify_clear_child_dentry_flag(p_inode, dentry); /* * Include parent/name in notification either if some notification |