From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933727Ab0J1VcD (ORCPT ); Thu, 28 Oct 2010 17:32:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9597 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760146Ab0J1Vbt (ORCPT ); Thu, 28 Oct 2010 17:31:49 -0400 From: Eric Paris Subject: [PATCH 02/20] fsnotify: implement ordering between notifiers To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: agruen@suse.de, tvrtko.ursulin@sophos.com Date: Thu, 28 Oct 2010 17:31:45 -0400 Message-ID: <20101028213145.24810.11059.stgit@paris.rdu.redhat.com> In-Reply-To: <20101028213139.24810.34058.stgit@paris.rdu.redhat.com> References: <20101028213139.24810.34058.stgit@paris.rdu.redhat.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org fanotify needs to be able to specify that some groups get events before others. They use this idea to make sure that a hierarchical storage manager gets access to files before programs which actually use them. This is purely infrastructure. Everything will have a priority of 0, but the infrastructure will exist for it to be non-zero. Signed-off-by: Eric Paris --- fs/notify/inode_mark.c | 9 +++++++-- fs/notify/vfsmount_mark.c | 6 +++++- include/linux/fsnotify_backend.h | 8 ++++++++ 3 files changed, 20 insertions(+), 3 deletions(-) diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 21ed106..4c29fcf 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -177,7 +177,8 @@ void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *mark, * Attach an initialized mark to a given inode. * These marks may be used for the fsnotify backend to determine which * event types should be delivered to which group and for which inodes. These - * marks are ordered according to the group's location in memory. + * marks are ordered according to priority, highest number first, and then by + * the group's location in memory. */ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, struct inode *inode, @@ -211,7 +212,11 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, goto out; } - if (mark->group < lmark->group) + if (mark->group->priority < lmark->group->priority) + continue; + + if ((mark->group->priority == lmark->group->priority) && + (mark->group < lmark->group)) continue; hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c index 56772b5..85eebff 100644 --- a/fs/notify/vfsmount_mark.c +++ b/fs/notify/vfsmount_mark.c @@ -169,7 +169,11 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, goto out; } - if (mark->group < lmark->group) + if (mark->group->priority < lmark->group->priority) + continue; + + if ((mark->group->priority == lmark->group->priority) && + (mark->group < lmark->group)) continue; hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list); diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index e40190d..8253295 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -129,6 +129,14 @@ struct fsnotify_group { wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */ unsigned int q_len; /* events on the queue */ unsigned int max_events; /* maximum events allowed on the list */ + /* + * Valid fsnotify group priorities. Events are send in order from highest + * priority to lowest priority. We default to the lowest priority. + */ + #define FS_PRIO_0 0 /* normal notifiers, no permissions */ + #define FS_PRIO_1 1 /* fanotify content based access control */ + #define FS_PRIO_2 2 /* fanotify pre-content access */ + unsigned int priority; /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */ spinlock_t mark_lock; /* protect marks_list */