Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753843Ab1EISrU (ORCPT ); Mon, 9 May 2011 14:47:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63660 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753445Ab1EISrT (ORCPT ); Mon, 9 May 2011 14:47:19 -0400 Message-ID: <4DC836B6.3040504@redhat.com> Date: Mon, 09 May 2011 14:47:18 -0400 From: Josef Bacik User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Dave Anderson CC: linux-kernel@vger.kernel.org, Josef Bacik Subject: Re: [PATCH] fs: kill default_llseek References: <843658708.415439.1304965839290.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com> In-Reply-To: <843658708.415439.1304965839290.JavaMail.root@zmail05.collab.prod.int.phx2.redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3553 Lines: 107 On 05/09/2011 02:30 PM, Dave Anderson wrote: > > > ----- Original Message ----- >> On 05/09/2011 02:03 PM, Dave Anderson wrote: >>> >>> On Thursday 05 May 2011 16:27:57 Josef Bacik wrote: >>>> Looking at this llseek stuff I noticed that default_llseek is the >>>> exact same as >>>> generic_file_llseek, so kill default_llseek. I patched this using >>>> spatch with >>>> just a simple >>>> >>>> @@ >>>> @@ >>>> >>>> - default_llseek >>>> + generic_file_llseek >>> >>> ... >>> >>>> diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c >>>> index d245cb2..6f37c39 100644 >>>> --- a/fs/proc/kcore.c >>>> +++ b/fs/proc/kcore.c >>>> @@ -558,7 +558,7 @@ static int open_kcore(struct inode *inode, >>>> struct file *filp) >>>> static const struct file_operations proc_kcore_operations = { >>>> .read = read_kcore, >>>> .open = open_kcore, >>>> - .llseek = default_llseek, >>>> + .llseek = generic_file_llseek, >>>> }; >>> >>>> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c >>>> index 74802bc5..0cafd9e 100644 >>>> --- a/fs/proc/vmcore.c >>>> +++ b/fs/proc/vmcore.c >>>> @@ -163,7 +163,7 @@ static ssize_t read_vmcore(struct file *file, >>>> char __user *buffer, >>>> >>>> static const struct file_operations proc_vmcore_operations = { >>>> .read = read_vmcore, >>>> - .llseek = default_llseek, >>>> + .llseek = generic_file_llseek, >>>> }; >>> >>> Both /proc/kcore and /proc/vmcore currently require >>> default_llseek(). >>> They were both changed to use generic_file_llseek(), but then >>> subsequently >>> reverted back to default_llseek(): >>> >>> commit c227e69028473c7c7994a9b0a2cc0034f3f7e0fe >>> Author: Arnd Bergmann >>> Date: Wed Sep 22 13:04:54 2010 -0700 >>> >>> /proc/vmcore: fix seeking >>> >>> Commit 73296bc611 ("procfs: Use generic_file_llseek in >>> /proc/vmcore") >>> broke seeking on /proc/vmcore. This changes it back to use >>> default_llseek >>> in order to restore the original behaviour. >>> ... >>> >>> >>> commit ceff1a770933e2ca2bf995b453dade4ec47a9878 >>> Author: Dave Anderson >>> Date: Wed Jan 12 17:00:36 2011 -0800 >>> >>> /proc/kcore: fix seeking >>> >>> Commit 34aacb2920 ("procfs: Use generic_file_llseek in >>> /proc/kcore") broke >>> seeking on /proc/kcore. This changes it back to use >>> default_llseek in >>> order to restore the original behavior. >>> ... >>> >> >> How is it getting s_maxbytes set to 0? I'm looking everywhere and I >> can't see how that can happen. It seems that anybody using sget should >> be getting it set to MAX_NONLFS so they should all be ok. I'm looking >> at proc in particular and it doesn't do anything special, so it should >> be ok. (Obviously it wasn't, I'm just trying to understand how we're >> getting s_maxbytes == 0 so we can fix that and kill default_llseek). >> Thanks, >> >> Josef > > Well, in the case of /proc/kcore, it was set to MAX_NON_LFS (2GB-1) > which is too small because the file offset values in the /proc/kcore > PT_LOAD segments may exceed or start beyond that offset value. > > I guessing the same thing was seen with /proc/vmcore, even > though Arnd's commit message implies that it was 0? > Ah yeah I guess that's it. Alright I'll think of something else. Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/