From: Al Viro <viro@zeniv.linux.org.uk>
To: Omar Sandoval <osandov@osandov.com>
Cc: Trond Myklebust <trondmy@hammerspace.com>,
"amir73il@gmail.com" <amir73il@gmail.com>,
"dhowells@redhat.com" <dhowells@redhat.com>,
"lsf-pc@lists.linux-foundation.org"
<lsf-pc@lists.linux-foundation.org>, "hch@lst.de" <hch@lst.de>,
"miklos@szeredi.hu" <miklos@szeredi.hu>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: [LSF/MM/BPF TOPIC] Allowing linkat() to replace the destination
Date: Sat, 18 Jan 2020 02:20:32 +0000 [thread overview]
Message-ID: <20200118022032.GR8904@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200118011734.GD295250@vader>
On Fri, Jan 17, 2020 at 05:17:34PM -0800, Omar Sandoval wrote:
> > No. This is completely wrong; just make it ->link_replace() and be done
> > with that; no extra arguments and *always* the same conditions wrt
> > positive/negative. One of the reasons why ->rename() tends to be
> > ugly (and a source of quite a few bugs over years) are those "if
> > target is positive/if target is negative" scattered over the instances.
> >
> > Make the choice conditional upon the positivity of target.
>
> Yup, you already convinced me that ->link_replace() is better in your
> last email.
FWIW, that might be not so simple ;-/ Reason: NFS-like stuff. Client
sees a negative in cache; the problem is how to decide whether to
tell the server "OK, I want normal link()" vs. "if it turns out that
someone has created it by the time you see the request, give do
a replacing link". Sure, if could treat ->link() telling you -EEXIST
as "OK, repeat it with ->link_replace(), then", but that's an extra
roundtrip...
Hell knows... I would really like to avoid any kind of ->atomic_open()
redux ;-/
next prev parent reply other threads:[~2020-01-18 2:20 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 12:49 [LSF/MM/BPF TOPIC] Allowing linkat() to replace the destination David Howells
2020-01-17 14:33 ` Trond Myklebust
2020-01-17 14:47 ` David Howells
2020-01-17 14:56 ` Trond Myklebust
2020-01-17 16:01 ` Al Viro
2020-01-17 15:46 ` Al Viro
2020-01-17 16:12 ` Trond Myklebust
2020-01-17 16:48 ` Al Viro
2020-01-17 16:36 ` Omar Sandoval
2020-01-17 16:59 ` Al Viro
2020-01-17 17:28 ` Omar Sandoval
2020-01-17 18:17 ` Al Viro
2020-01-17 20:22 ` Omar Sandoval
2020-01-17 22:22 ` Al Viro
2020-01-17 23:54 ` Omar Sandoval
2020-01-18 0:47 ` Al Viro
2020-01-18 1:17 ` Omar Sandoval
2020-01-18 2:20 ` Al Viro [this message]
2020-01-21 23:05 ` Omar Sandoval
2020-01-22 6:57 ` Amir Goldstein
2020-01-22 22:10 ` Omar Sandoval
2020-01-23 3:47 ` Al Viro
2020-01-23 7:16 ` Dave Chinner
2020-01-23 7:47 ` Amir Goldstein
2020-01-24 21:25 ` Dave Chinner
2020-01-31 5:24 ` Darrick J. Wong
2020-01-31 5:29 ` hch
2020-01-31 7:00 ` Amir Goldstein
2020-01-31 20:33 ` Omar Sandoval
2020-01-31 21:55 ` Amir Goldstein
2020-01-28 1:27 ` Omar Sandoval
2020-01-28 14:35 ` David Howells
2020-01-31 5:31 ` hch
2020-01-31 8:04 ` David Howells
2020-01-31 8:56 ` Amir Goldstein
2020-01-22 9:53 ` David Howells
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