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From: "Colin Walters" <walters@verbum.org>
To: "Jeff Layton" <jlayton@kernel.org>, "Dave Chinner" <david@fromorbit.com>
Cc: "Al Viro" <viro@zeniv.linux.org.uk>,
	linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-nfs@vger.kernel.org, "David Howells" <dhowells@redhat.com>,
	"Frank Filz" <ffilzlnx@mindspring.com>
Subject: Re: [PATCH] vfs: report an inode version in statx for IS_I_VERSION inodes
Date: Fri, 26 Aug 2022 04:44:23 -0400	[thread overview]
Message-ID: <0c5ef1d2-235c-48c1-9a7a-5e52f3a34855@www.fastmail.com> (raw)
In-Reply-To: <0339f5f540010ba1bae74121d33c0643f26fefab.camel@kernel.org>

Bigger picture, I think eventually I'm going to rework stuff related to my use case to be more similar to the container stack, specifically using overlayfs; so it's quite possible by the time iversion is exposed to userspace, I won't have any strong want/need of it myself.

On Thu, Aug 25, 2022, at 3:48 PM, Jeff Layton wrote:

> IOW, should this value mean that something _did_ change in the inode or
> that something _may_ have changed in it?

In my case it's basically the same as IMA - we want to only compute the sha256 digest of files that actually changed.  Some false positives are hence OK - but that also means the usefulness of the feature degrades in proportion to that number.

A bit more detail:

I didn't deep dive into the XFS mention about internal/background iversion changes, but AIUI at a high level it sounds like those iversion changes happen mainly (only?) when the file is recently created and pending writeback, which doesn't seem like a problem in practice.  I do agree with Ingo's old quote about atime though in https://lwn.net/Articles/244829/ and this thread reminded me to use `noatime` on my main workstation (again; I'd recently changed how I provision it).





  reply	other threads:[~2022-08-26  8:44 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-19 11:56 [PATCH] vfs: report an inode version in statx for IS_I_VERSION inodes Jeff Layton
2022-08-23 10:01 ` Florian Weimer
2022-08-23 10:16   ` Jeff Layton
2022-08-23 21:53 ` Dave Chinner
2022-08-24 10:17   ` Jeff Layton
2022-08-25 18:48   ` Colin Walters
2022-08-25 19:48     ` Jeff Layton
2022-08-26  8:44       ` Colin Walters [this message]
2022-08-27  7:38     ` Greg KH

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