linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andreas Dilger <adilger@dilger.ca>
To: mtk.manpages@gmail.com
Cc: Josef Bacik <josef@redhat.com>,
	Eric Gouriou <egouriou@google.com>,
	inux-man@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Lucian Adrian Grijincu <lucian.grijincu@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Dave Chinner <dchinner@redhat.com>
Subject: Re: [PATCH] fallocate.2: add FALLOC_FL_PUNCH_HOLE flag definition
Date: Tue, 20 Sep 2011 23:25:40 -0600	[thread overview]
Message-ID: <804BB4B7-E19F-41EE-81A3-25D4389B54B9@dilger.ca> (raw)
In-Reply-To: <CAKgNAkhCptHn_UxReeZeSNaP0yNr+iWYd3fcxrD_PHohqQVxuQ@mail.gmail.com>

On 2011-09-20, at 10:11 PM, Michael Kerrisk wrote:
> Thanks for this patch. As noted in another mail, Lucian also sent a
> patch for FALLOC_FL_PUNCH_HOLE, and I applied his patch first, and
> then added some pieces from yours, as well as some of my own edits.
> 
> However, the addition of a second class of operation to the man page
> made it clear that some significant restructuring of the page is
> required. So I substantially reworked the page, including the
> preexisting material on the default "file allocation" operation (Dave
> C please note).
> 
> \b.TP
> .B EINVAL
> .I offset
> was less than 0, or
> .I len
> was less than or equal to 0.

I wasn't sure if this is a bug in the manpage or actually how it is done
in the kernel, but it seems this is a kernel implementation issue...

Does it make sense to return an error if len == 0?  That just adds extra
complexity on the part of the application, and doesn't reduce complexity
in the kernel (whether the kernel checks for len == 0 and returns 0 or
-EINVAL is not any different).  read() and write() and malloc() all allow
a length of zero to succeed, since applications may compute this length
and sometimes it is zero.

Cheers, Andreas






  reply	other threads:[~2011-09-21  5:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-15 17:07 [PATCH] fallocate.2: add FALLOC_FL_PUNCH_HOLE flag definition Josef Bacik
2011-09-19  5:08 ` Michael Kerrisk
2011-09-19  6:32   ` Dave Chinner
2011-09-21  4:11   ` Michael Kerrisk
2011-09-21  5:25     ` Andreas Dilger [this message]
2011-09-21  5:49       ` Michael Kerrisk

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=804BB4B7-E19F-41EE-81A3-25D4389B54B9@dilger.ca \
    --to=adilger@dilger.ca \
    --cc=dchinner@redhat.com \
    --cc=egouriou@google.com \
    --cc=inux-man@vger.kernel.org \
    --cc=josef@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lucian.grijincu@gmail.com \
    --cc=mtk.manpages@gmail.com \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).