From: Roland Mainz <roland.mainz@nrubsig.org>
To: cygwin-developers@cygwin.com
Subject: Re: SEEK_HOLE Support in Cygwin?
Date: Thu, 24 Aug 2023 14:03:04 +0200 [thread overview]
Message-ID: <CAKAoaQ=b=ybsevaPdZS0euPvRUX2a8PakFGrWx=YmDfoR=Hh7A@mail.gmail.com> (raw)
In-Reply-To: <CALXu0Uc7CYc4LQZCw_3zumgxHbmE+RTcy9P26FdvSKvCfc-exQ@mail.gmail.com>
On Mon, Aug 21, 2023 at 6:33 AM Cedric Blancher
<cedric.blancher@gmail.com> wrote:
> On Thu, 10 Aug 2023 at 10:28, Corinna Vinschen
> <corinna-cygwin@cygwin.com> wrote:
> > On Aug 10 04:43, Cedric Blancher wrote:
[snip]
> > > > Note that this defaults to the default behaviour described in the
> > > > Linux man page, see https://man7.org/linux/man-pages/man2/lseek.2.html
> > > >
> > > > I.e., "In the simplest implementation, a filesystem can support the
> > > > operations by making SEEK_HOLE always return the offset of the end of
> > > > the file, and making SEEK_DATA always return offset"
> > >
> > > So this supports multiple holes in one file, right?
> >
> > Curious question. Cygwin supports sparse files for ages. Only the
> > lseek options SEEK_HOLE and SEEK_DATA are new.
>
> Is SEEK_HOLE support enabled for MSFT NFSv3 client?
The NFSv3 protocol does not support sparse files.
Support for sparse files, including SEEK_HOLE/SEEK_DATA, and
allocating/deallocating blocks was added in NFSv4.2 (see
https://datatracker.ietf.org/doc/html/rfc7862#page-32).
What needs to be done now is to add NFSv4.2 READ_PLUS support to the
CITI NFSv4.[12] driver, and hook up |FILE_SUPPORTS_SPARSE_FILES|
support - then sparse files should work.
Question for Corinna:
Does Cygwin support allocation/deallocation of filesystem blocks via
Linux's |fallocate()|-API ?
----
Bye,
Roland
--
__ . . __
(o.\ \/ /.o) roland.mainz@nrubsig.org
\__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer
/O /==\ O\ TEL +49 641 3992797
(;O/ \/ \O;)
next prev parent reply other threads:[~2023-08-24 12:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-06 17:14 Cedric Blancher
2023-08-07 8:33 ` Corinna Vinschen
2023-08-09 15:30 ` Corinna Vinschen
2023-08-10 2:43 ` Cedric Blancher
2023-08-10 8:28 ` Corinna Vinschen
2023-08-21 4:33 ` Cedric Blancher
2023-08-21 8:32 ` Corinna Vinschen
2023-08-24 12:03 ` Roland Mainz [this message]
2023-08-25 9:05 ` Corinna Vinschen
2023-08-25 11:09 ` Roland Mainz
2023-08-25 11:23 ` Corinna Vinschen
2023-08-25 11:43 ` Corinna Vinschen
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='CAKAoaQ=b=ybsevaPdZS0euPvRUX2a8PakFGrWx=YmDfoR=Hh7A@mail.gmail.com' \
--to=roland.mainz@nrubsig.org \
--cc=cygwin-developers@cygwin.com \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).