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From: Pavel Raiskup <praiskup@redhat.com>
To: bug-tar@gnu.org
Cc: Joerg Schilling <Joerg.Schilling@fokus.fraunhofer.de>,
	eggert@cs.ucla.edu, mhw@netris.org, linux-btrfs@vger.kernel.org
Subject: Re: [Bug-tar] [PATCH] Re: Detection of sparse files is broken on btrfs
Date: Wed, 10 Jan 2018 13:00:19 +0100	[thread overview]
Message-ID: <3363772.gnJ4KdsmPr@nb.usersys.redhat.com> (raw)
In-Reply-To: <5a54965c.D6Hm4qlW4vP6gFVx%Joerg.Schilling@fokus.fraunhofer.de>

On Tuesday, January 9, 2018 11:15:56 AM CET Joerg Schilling wrote:
> Pavel Raiskup <praiskup@redhat.com> wrote:
> 
> > On Tuesday, January 9, 2018 8:59:06 AM CET Paul Eggert wrote:
> > > Pavel Raiskup wrote:
> > > > So what about special casing that filesystem, where we can lseek() for
> > > > holes anyway?
> > > 
> > > If we can lseek for holes, then why not just do that?
> >
> > Checking whether lseek() actually works costs some additional syscalls _per
> > sparse_ file;  checking for ST_NBLOCKS() is without this penalty.
> 
> Well, star does this since a long time and the penalty is a few microseconds.

It would be interesting to see how network filesystems are affected.

Pavel




  reply	other threads:[~2018-01-10 12:00 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <87fu7hccci.fsf@netris.org>
2018-01-09  7:46 ` [PATCH] Re: [Bug-tar] Detection of sparse files is broken on btrfs Pavel Raiskup
2018-01-09  7:59   ` [Bug-tar] [PATCH] " Paul Eggert
2018-01-09  8:25     ` Pavel Raiskup
2018-01-09 10:15       ` Joerg Schilling
2018-01-10 12:00         ` Pavel Raiskup [this message]
2018-01-09 10:12     ` Joerg Schilling

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