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From:   "NeilBrown" <neilb@suse.de>
To:     "Jeff Layton" <jlayton@kernel.org>
Cc:     "Dave Chinner" <david@fromorbit.com>,
        "Mimi Zohar" <zohar@linux.ibm.com>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org,
        linux-ext4@vger.kernel.org,
        "Trond Myklebust" <trondmy@hammerspace.com>
Subject: Re: [PATCH] iversion: update comments with info about atime updates
In-reply-to: <6cbcb33d33613f50dd5e485ecbf6ce7e305f3d6f.camel@kernel.org>
References: <20220822133309.86005-1-jlayton@kernel.org>,
 <ceb8f09a4cb2de67f40604d03ee0c475feb3130a.camel@linux.ibm.com>,
 <f17b9d627703bee2a7b531a051461671648a9dbd.camel@kernel.org>,
 <18827b350fbf6719733fda814255ec20d6dcf00f.camel@linux.ibm.com>,
 <4cc84440d954c022d0235bf407a60da66a6ccc39.camel@kernel.org>,
 <20220822233231.GJ3600936@dread.disaster.area>,
 <6cbcb33d33613f50dd5e485ecbf6ce7e305f3d6f.camel@kernel.org>
Date:   Tue, 23 Aug 2022 21:38:07 +1000
Message-id: <166125468756.23264.2859374883806269821@noble.neil.brown.name>
Precedence: bulk

On Tue, 23 Aug 2022, Jeff Layton wrote:
> So, we can refer to that and simply say:
> 
> "If the function updates the mtime or ctime on the inode, then the
> i_version should be incremented. If only the atime is being updated,
> then the i_version should not be incremented. The exception to this rule
> is explicit atime updates via utimes() or similar mechanism, which
> should result in the i_version being incremented."

Is that exception needed?  utimes() updates ctime.

https://man7.org/linux/man-pages/man2/utimes.2.html

doesn't say that, but

https://pubs.opengroup.org/onlinepubs/007904875/functions/utimes.html

does, as does the code.

NeilBrown