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From: Theodore Ts'o <tytso@mit.edu>
To: Phillip Susi <psusi@ubuntu.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH] e2fslibs: fix llseek on i386
Date: Thu, 24 Jan 2013 15:32:30 -0500	[thread overview]
Message-ID: <20130124203230.GA20776@thunk.org> (raw)
In-Reply-To: <5101980D.30904@ubuntu.com>

On Thu, Jan 24, 2013 at 03:22:37PM -0500, Phillip Susi wrote:
> 
> On 1/24/2013 2:51 PM, Theodore Ts'o wrote:
> > How did you find this?  I've done a quick search for SEEK_CUR, and
> > it looks like only place where this could cause a problem is with 
> > e2image.  And a quick test of a i386 version of e2image with a
> > large file system is that it does indeed blow up with an
> > "Inappropriate ioctl for device" error.
> 
> That's where I found it, but the error should be "seek: Value too
> large for defined data type"

Well, I did my testing using an i386 debian/testing chroot running
under a x86-64 3.8.0-rc3 kernel.  I'm guessing it was the use of a
32-bit userspace / 64-bit kernel that probably explains the
difference.

> > Is there any other potential problems that are caused by this bug?
> > I like to explain the impacts of bug fixes in libext2fs for folks
> > who are doing bug fix / code archeology.
> 
> If e2image is the only internal user of the call with SEEK_CUR, then I
> guess it only affects any external users of the library who were doing
> this ( I am not aware of any ).

Well, there are some binaries that aren't usually built by most
distributions (make-sparse and copy-sparse), but in terms of primary
e2fsprogs programs (mke2fs, e2fskc, tune2fs, chattr, lsattr, etc.)
nope, none of them use SEEK_CUR.

The lib/ext2fs/fileio.c file does use SEEK_CUR, which means it might
impact 3rd party packages such as e2tools and ext2fuse (although
that's generally only used on Mac and Windows systems).

Cheers,

					- Ted

  reply	other threads:[~2013-01-24 20:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-24 16:21 [PATCH] e2fslibs: fix llseek on i386 Phillip Susi
2013-01-24 19:51 ` Theodore Ts'o
2013-01-24 20:22   ` Phillip Susi
2013-01-24 20:32     ` Theodore Ts'o [this message]
2013-01-25  2:25       ` Zheng Liu
2013-01-25  2:16         ` Theodore Ts'o
2013-01-25  2:48           ` Zheng Liu
2013-01-25  4:13 ` Theodore Ts'o
2013-01-25  4:14   ` [PATCH] libext2fs: fix ext2fs_llseek " Theodore Ts'o
2013-01-25  4:34     ` Phillip Susi

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