From patchwork Tue Jan 27 12:45:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: ZhangZhen X-Patchwork-Id: 5717731 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7EE94C058D for ; Tue, 27 Jan 2015 12:46:59 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 74014201BB for ; Tue, 27 Jan 2015 12:46:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 561F220160 for ; Tue, 27 Jan 2015 12:46:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758335AbbA0Mq2 (ORCPT ); Tue, 27 Jan 2015 07:46:28 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:46710 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932483AbbA0MqZ (ORCPT ); Tue, 27 Jan 2015 07:46:25 -0500 Received: from 172.24.2.119 (EHLO szxeml434-hub.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CIP93587; Tue, 27 Jan 2015 20:45:58 +0800 (CST) Received: from [127.0.0.1] (10.111.68.57) by szxeml434-hub.china.huawei.com (10.82.67.225) with Microsoft SMTP Server id 14.3.158.1; Tue, 27 Jan 2015 20:45:49 +0800 Message-ID: <54C78879.3010603@huawei.com> Date: Tue, 27 Jan 2015 20:45:45 +0800 From: Zhang Zhen User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: , CC: Wang Nan , , , Subject: [RESEND PATCH] inotify: update documentation to reflect code changes References: <1418785193-31576-1-git-send-email-zhenzhang.zhang@huawei.com> In-Reply-To: <1418785193-31576-1-git-send-email-zhenzhang.zhang@huawei.com> X-Originating-IP: [10.111.68.57] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The inotify kernel interface was removed by Eric Paris in this commit: 2dfc1ca inotify: remove inotify in kernel interface. Signed-off-by: Zhang Zhen --- Documentation/filesystems/inotify.txt | 120 +--------------------------------- 1 file changed, 2 insertions(+), 118 deletions(-) diff --git a/Documentation/filesystems/inotify.txt b/Documentation/filesystems/inotify.txt index cfd0271..9b74b45 100644 --- a/Documentation/filesystems/inotify.txt +++ b/Documentation/filesystems/inotify.txt @@ -69,123 +69,7 @@ Prototypes: int inotify_rm_watch (int fd, __u32 mask); -(iii) Kernel Interface - -Inotify's kernel API consists a set of functions for managing watches and an -event callback. - -To use the kernel API, you must first initialize an inotify instance with a set -of inotify_operations. You are given an opaque inotify_handle, which you use -for any further calls to inotify. - - struct inotify_handle *ih = inotify_init(my_event_handler); - -You must provide a function for processing events and a function for destroying -the inotify watch. - - void handle_event(struct inotify_watch *watch, u32 wd, u32 mask, - u32 cookie, const char *name, struct inode *inode) - - watch - the pointer to the inotify_watch that triggered this call - wd - the watch descriptor - mask - describes the event that occurred - cookie - an identifier for synchronizing events - name - the dentry name for affected files in a directory-based event - inode - the affected inode in a directory-based event - - void destroy_watch(struct inotify_watch *watch) - -You may add watches by providing a pre-allocated and initialized inotify_watch -structure and specifying the inode to watch along with an inotify event mask. -You must pin the inode during the call. You will likely wish to embed the -inotify_watch structure in a structure of your own which contains other -information about the watch. Once you add an inotify watch, it is immediately -subject to removal depending on filesystem events. You must grab a reference if -you depend on the watch hanging around after the call. - - inotify_init_watch(&my_watch->iwatch); - inotify_get_watch(&my_watch->iwatch); // optional - s32 wd = inotify_add_watch(ih, &my_watch->iwatch, inode, mask); - inotify_put_watch(&my_watch->iwatch); // optional - -You may use the watch descriptor (wd) or the address of the inotify_watch for -other inotify operations. You must not directly read or manipulate data in the -inotify_watch. Additionally, you must not call inotify_add_watch() more than -once for a given inotify_watch structure, unless you have first called either -inotify_rm_watch() or inotify_rm_wd(). - -To determine if you have already registered a watch for a given inode, you may -call inotify_find_watch(), which gives you both the wd and the watch pointer for -the inotify_watch, or an error if the watch does not exist. - - wd = inotify_find_watch(ih, inode, &watchp); - -You may use container_of() on the watch pointer to access your own data -associated with a given watch. When an existing watch is found, -inotify_find_watch() bumps the refcount before releasing its locks. You must -put that reference with: - - put_inotify_watch(watchp); - -Call inotify_find_update_watch() to update the event mask for an existing watch. -inotify_find_update_watch() returns the wd of the updated watch, or an error if -the watch does not exist. - - wd = inotify_find_update_watch(ih, inode, mask); - -An existing watch may be removed by calling either inotify_rm_watch() or -inotify_rm_wd(). - - int ret = inotify_rm_watch(ih, &my_watch->iwatch); - int ret = inotify_rm_wd(ih, wd); - -A watch may be removed while executing your event handler with the following: - - inotify_remove_watch_locked(ih, iwatch); - -Call inotify_destroy() to remove all watches from your inotify instance and -release it. If there are no outstanding references, inotify_destroy() will call -your destroy_watch op for each watch. - - inotify_destroy(ih); - -When inotify removes a watch, it sends an IN_IGNORED event to your callback. -You may use this event as an indication to free the watch memory. Note that -inotify may remove a watch due to filesystem events, as well as by your request. -If you use IN_ONESHOT, inotify will remove the watch after the first event, at -which point you may call the final inotify_put_watch. - -(iv) Kernel Interface Prototypes - - struct inotify_handle *inotify_init(struct inotify_operations *ops); - - inotify_init_watch(struct inotify_watch *watch); - - s32 inotify_add_watch(struct inotify_handle *ih, - struct inotify_watch *watch, - struct inode *inode, u32 mask); - - s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode, - struct inotify_watch **watchp); - - s32 inotify_find_update_watch(struct inotify_handle *ih, - struct inode *inode, u32 mask); - - int inotify_rm_wd(struct inotify_handle *ih, u32 wd); - - int inotify_rm_watch(struct inotify_handle *ih, - struct inotify_watch *watch); - - void inotify_remove_watch_locked(struct inotify_handle *ih, - struct inotify_watch *watch); - - void inotify_destroy(struct inotify_handle *ih); - - void get_inotify_watch(struct inotify_watch *watch); - void put_inotify_watch(struct inotify_watch *watch); - - -(v) Internal Kernel Implementation +(iii) Internal Kernel Implementation Each inotify instance is represented by an inotify_handle structure. Inotify's userspace consumers also have an inotify_device which is @@ -198,7 +82,7 @@ See fs/notify/inotify/inotify_fsnotify.c and fs/notify/inotify/inotify_user.c for the locking and lifetime rules. -(vi) Rationale +(iv) Rationale Q: What is the design decision behind not tying the watch to the open fd of the watched object?