GNU bug report logs - #21790
[PATCH] coreutils/cp: handle EOF extents correctly

Previous Next

Full log

View this message in rfc822 format

From: Pádraig Brady <P <at> draigBrady.com>
To: Dmitry Monakhov <dmonakhov <at> openvz.org>, 21790 <at> debbugs.gnu.org
Cc: vvs <at> parallels.com, devel <at> openvz.org
Subject: bug#21790: [PATCH] coreutils/cp: handle EOF extents correctly
Date: Fri, 30 Oct 2015 16:57:04 +0000

On 30/10/15 09:02, Dmitry Monakhov wrote:
> fallocate can allocate extens beyond EOF via FALLOC_FL_KEEP_SIZE.
> Currenly sparse engine tries to copy such extents which is wrong and
> result in silent data corruption (leave file with incorrect size).
> 
> ##TESTCASE
> echo blabla > sparse_falloc.in
> truncate -s 2M sparse_falloc.in
> fallocate -n -o 4M -l 1M sparse_falloc.in
> cp sparse_falloc.in sparse_falloc.out
> cmp sparse_falloc.in sparse_falloc.out

Ouch.  Thanks for the analysis and patch.
It looks correct.  I'll analyze further before applying.

thanks!
Pádraig.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.