Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933397AbbLHJvu (ORCPT ); Tue, 8 Dec 2015 04:51:50 -0500 Received: from mail-wm0-f49.google.com ([74.125.82.49]:34497 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933369AbbLHJv1 (ORCPT ); Tue, 8 Dec 2015 04:51:27 -0500 From: Roman Pen Cc: Roman Pen , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [RFC PATCH 3/3] debugfs: update some bits of documentation Date: Tue, 8 Dec 2015 10:51:06 +0100 Message-Id: <1449568266-17404-4-git-send-email-r.peniaev@gmail.com> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1449568266-17404-1-git-send-email-r.peniaev@gmail.com> References: <1449568266-17404-1-git-send-email-r.peniaev@gmail.com> To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2296 Lines: 53 Include description of 'debugfs_create_dir_with_tmpfiles()' call. Signed-off-by: Roman Pen Cc: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org --- Documentation/filesystems/debugfs.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt index 4f45f71..150fabf 100644 --- a/Documentation/filesystems/debugfs.txt +++ b/Documentation/filesystems/debugfs.txt @@ -36,6 +36,31 @@ wrong. If ERR_PTR(-ENODEV) is returned, that is an indication that the kernel has been built without debugfs support and none of the functions described below will work. +Another way to create a directory where temporary files will be created +on demand is: + + struct dentry *debugfs_create_dir_with_tmpfiles(const char *name, + umode_t mode, struct dentry *parent, void *data, + const struct file_operations *fops); + +This function creates a directory in debugfs with the given name with +possibility to create temporary files on demand. Any attempt to open +a non-existent file in that directory will create a temporary file, +wich will be deleted when the last file descriptor is closed. This +temporary file is very similar to opening a directory with O_TMPFILE, +with the difference that a resulting dentry has a name, but still is +unhashed, so is invisible to outer world and can never be reached via +any pathname. + +How those temporary files on demand can be used? This is a way to provide +one additional parameter in a file name and specify an object name. E.g.: + + # cat /sys/kernel/debug/my_objects/$UUID + +Where $UUID is a UUID of an object which should be requested. This $UUID +file will never appear in lookup and will be deleted when 'cat' closes last +file descriptor. + The most general way to create a file within a debugfs directory is with: struct dentry *debugfs_create_file(const char *name, umode_t mode, -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/