linux-kernel - Re: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing

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Message-ID: <4df4ef0c0801111415r85c602axdd5d4c85e5bf40ed@mail.gmail.com>
Date:	Sat, 12 Jan 2008 01:15:45 +0300
From:	"Anton Salikhmetov" <salikhmetov@...il.com>
To:	"Peter Staubach" <staubach@...hat.com>
Cc:	linux-mm@...ck.org, jakob@...hought.net,
	linux-kernel@...r.kernel.org, Valdis.Kletnieks@...edu,
	riel@...hat.com, ksm@...dk, jesper.juhl@...il.com
Subject: Re: [PATCH 2/2][RFC][BUG] msync: updating ctime and mtime at syncing

2008/1/12, Peter Staubach <staubach@...hat.com>:
> Anton Salikhmetov wrote:
> > 2008/1/11, Peter Staubach <staubach@...hat.com>:
> >
> >> Anton Salikhmetov wrote:
> >>
> >>> From: Anton Salikhmetov <salikhmetov@...il.com>
> >>>
> >>> The patch contains changes for updating the ctime and mtime fields for memory mapped files:
> >>>
> >>> 1) adding a new flag triggering update of the inode data;
> >>> 2) implementing a helper function for checking that flag and updating ctime and mtime;
> >>> 3) updating time stamps for mapped files in sys_msync() and do_fsync().
> >>>
> >> Sorry, one other issue to throw out too -- an mmap'd block device
> >> should also have its inode time fields updated.  This is a little
> >> tricky because the inode referenced via mapping->host isn't the
> >> one that needs to have the time fields updated on.
> >>
> >> I have attached the patch that I submitted last.  It is quite out
> >> of date, but does show my attempt to resolve some of these issues.
> >>
> >
> > Thanks for your feedback!
> >
> > Now I'm looking at your solution and thinking about which parts of it
> > I could adapt to the infrastructure I'm trying to develop.
> >
> > However, I would like to address the block device case within
> > a separate project. But for now, I want the msync() and fsync()
> > system calls to update ctime and mtime at least for memory-mapped
> > regular files properly. I feel that even this little improvement could address
> > many customer's troubles such as the one Jacob Oestergaard reported
> > in the bug #2645.
>
> Not that I disagree and I also have customers who would really like
> to see this situation addressed so that I can then fix it in RHEL,
> but the block device issue was raised by Andrew Morton during my
> first attempt to get a patch integrated.
>
> Just so that you are aware of who has raised which issues...  :-)

Yes, I remember that email by Andrew Morton (http://lkml.org/lkml/2006/6/19/6).
In fact, I went over that thread many times while working on my
solution for this bug.

Nevertheless, I presume the block device case to be addressed in a
separate patch
series, just like the "auto-updating" feature.

>
>     Thanx...
>
>        ps
>
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