NetBSD Problem Report #46246

From dholland@netbsd.org  Thu Mar 22 16:45:49 2012
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Date: Thu, 22 Mar 2012 16:45:58 +0000 (UTC)
From: dholland@netbsd.org
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To: gnats-bugs@gnats.NetBSD.org
Subject: tmpfs does not support sparse files (!?)
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>Number:         46246
>Category:       kern
>Synopsis:       tmpfs does not support sparse files (!?)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Mar 22 16:50:01 +0000 2012
>Last-Modified:  Mon Mar 26 05:45:01 +0000 2012
>Originator:     David A. Holland
>Release:        NetBSD 5.99.65
>Organization:
>Environment:
System: NetBSD  5.99.65 NetBSD 5.99.65 (GENERIC) #65: Mon Feb 13 01:38:30 EST 2012  dholland@valkyrie:/disk/disk1/home/dholland/netbsd/quotafix/src/sys/arch/i386/compile/obj.i386/GENERIC i386
Architecture: i386
Machine: i386
>Description:

tmpfs does not appear to support sparse files.

>How-To-Repeat:

# cat /root/x.c
#include <stdlib.h>
#include <unistd.h>
#include <err.h>

int main(int argc, char *argv[]) {
    if (truncate(argv[1], atol(argv[2])))
        err(1, "truncate");
    return 0;
}
# ls -l
# touch foo
# /root/x foo `expr 1024 \* 1024 \* 4`
# du foo
4096    foo
# 

>Fix:
send rmind chocolate? :-)

>Audit-Trail:
From: yamt@mwd.biglobe.ne.jp (YAMAMOTO Takashi)
To: gnats-bugs@NetBSD.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
	netbsd-bugs@netbsd.org
Subject: Re: kern/46246: tmpfs does not support sparse files (!?)
Date: Mon, 26 Mar 2012 05:41:33 +0000 (UTC)

 > tmpfs does not appear to support sparse files.

 iirc, a tmpfs file can be sparse as its underlying aobj does.
 but its GETATTR doesn't know the sparseness.

 YAMAMOTO Takarhi

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