From patchwork Fri Aug 26 21:47:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 12956655 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8C0AC3DA6B for ; Fri, 26 Aug 2022 21:49:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345310AbiHZVt1 (ORCPT ); Fri, 26 Aug 2022 17:49:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345237AbiHZVtL (ORCPT ); Fri, 26 Aug 2022 17:49:11 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D848E86B0; Fri, 26 Aug 2022 14:47:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 77380611B8; Fri, 26 Aug 2022 21:47:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0523C433C1; Fri, 26 Aug 2022 21:47:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661550470; bh=gLz5Ruse5elfcIgvMDWKp/BReownfZtaD32WbbWr76A=; h=From:To:Cc:Subject:Date:From; b=FfcrPUI2YtcwItJUli98wIyMhirsFq8i/ojoPLXVo4YVq5CrRAammwmg8IU+jM7nK h3ZWcORGhfZ5E2MPhkdk4hMmEMx67+WTrQpYNf22qqBjkysL7AsDGszadAod937Rbl kMGcojNQDcJaTl5ErtpYRKwsRj8WscbmbfDqROL4CeifPc/+ZerLa3gGarI8KU03o/ VT/ujDmyDKADuDo6MH9uECUTCmhpHyBKtyvxWcNWTJzjZYnmdL5BpVvNK6I95LeVgt tA6Eq1HK4BaVHo+SoOMUxdSzH1nKqDzEOuJLX2D0LkzyE2OESJYNM/0pCWOM4/rlkI c+/rmFfC8elyQ== From: Jeff Layton To: tytso@mit.edu, adilger.kernel@dilger.ca, djwong@kernel.org, david@fromorbit.com, trondmy@hammerspace.com, neilb@suse.de, viro@zeniv.linux.org.uk, zohar@linux.ibm.com, xiubli@redhat.com, chuck.lever@oracle.com, lczerner@redhat.com, jack@suse.cz, brauner@kernel.org, linux-man@vger.kernel.org Cc: linux-api@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ceph@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org Subject: [man-pages PATCH] statx, inode: document the new STATX_INO_VERSION field Date: Fri, 26 Aug 2022 17:47:47 -0400 Message-Id: <20220826214747.134964-1-jlayton@kernel.org> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org We're planning to expose the inode change attribute via statx. Document what this value means and what an observer can infer from a change in its value. Signed-off-by: Jeff Layton --- man2/statx.2 | 13 +++++++++++++ man7/inode.7 | 10 ++++++++++ 2 files changed, 23 insertions(+) diff --git a/man2/statx.2 b/man2/statx.2 index 0d1b4591f74c..644fb251f114 100644 --- a/man2/statx.2 +++ b/man2/statx.2 @@ -62,6 +62,7 @@ struct statx { __u32 stx_dev_major; /* Major ID */ __u32 stx_dev_minor; /* Minor ID */ __u64 stx_mnt_id; /* Mount ID */ + __u64 stx_ino_version; /* Inode change attribute */ }; .EE .in @@ -247,6 +248,7 @@ STATX_BTIME Want stx_btime STATX_ALL The same as STATX_BASIC_STATS | STATX_BTIME. It is deprecated and should not be used. STATX_MNT_ID Want stx_mnt_id (since Linux 5.8) +STATX_INO_VERSION Want stx_ino_version (since Linux 6.1) .TE .in .PP @@ -411,6 +413,17 @@ and corresponds to the number in the first field in one of the records in For further information on the above fields, see .BR inode (7). .\" +.TP +.I stx_ino_version +The inode version, also known as the inode change attribute. This +value is intended to change any time there is an inode status change. Any +operation that would cause the stx_ctime to change should also cause +stx_ino_version to change, even when there is no apparent change to the +stx_ctime due to timestamp granularity. +.IP +Note that an observer cannot infer anything about the nature or +magnitude of the change from the value of this field. A change in this value +only indicates that there may have been an explicit change in the inode. .SS File attributes The .I stx_attributes diff --git a/man7/inode.7 b/man7/inode.7 index 9b255a890720..d296bb6df70c 100644 --- a/man7/inode.7 +++ b/man7/inode.7 @@ -184,6 +184,16 @@ Last status change timestamp (ctime) This is the file's last status change timestamp. It is changed by writing or by setting inode information (i.e., owner, group, link count, mode, etc.). +.TP +Inode version (i_version) +(not returned in the \fIstat\fP structure); \fIstatx.stx_ino_version\fP +.IP +This is the inode change attribute. Any operation that would result in a ctime +change should also result in a change to this value. The value must change even +in the case where the ctime change is not evident due to timestamp granularity. +An observer cannot infer anything from the actual value about the nature or +magnitude of the change. If it is different from the last time it was checked, +then something may have made an explicit change to the inode. .PP The timestamp fields report time measured with a zero point at the .IR Epoch ,