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From: Aaron Straus <aaron-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Neil Brown <neilb@suse.de>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	Trond Myklebust <trond.myklebust@fys.uio.no>,
	LKML Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [NFS] blocks of zeros (NULLs) in NFS files in kernels >= 2.6.20
Date: Thu, 11 Sep 2008 10:19:08 -0700	[thread overview]
Message-ID: <20080911171908.GE12037@merfinllc.com> (raw)
In-Reply-To: <8BFB4AE0-3EF1-41FA-A13B-27E380A79950@oracle.com>

Hi,

On Sep 11 12:55 PM, Chuck Lever wrote:
> A more thorough review of the NFS write and flush logic that exists in
> 2.6.27 is needed if we choose to recognize this issue as a real
> problem.

Yep.  

Sorry.  I didn't mean we should revert the hunk.  I was just trying to
help identify the cause of the new behavior.

I think this is a real problem albeit not a "serious" one.  Network
file-systems usually try to avoid readers seeing blocks of zeros in
files, especially in this simple writer/reader case.

It wouldn't be bad if the file is written out of order occasionally, but
we see this constantly now.

We cannot write/read log files to NFS mounts reliably any more.  That
seems like a valid use case which no longer works?

Anyway, thanks for your time!

				=a=



-- 
===================
Aaron Straus
aaron-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org

WARNING: multiple messages have this Message-ID (diff)
From: Aaron Straus <aaron@merfinllc.com>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Neil Brown <neilb@suse.de>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	Trond Myklebust <trond.myklebust@fys.uio.no>,
	LKML Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [NFS] blocks of zeros (NULLs) in NFS files in kernels >= 2.6.20
Date: Thu, 11 Sep 2008 10:19:08 -0700	[thread overview]
Message-ID: <20080911171908.GE12037@merfinllc.com> (raw)
In-Reply-To: <8BFB4AE0-3EF1-41FA-A13B-27E380A79950@oracle.com>

Hi,

On Sep 11 12:55 PM, Chuck Lever wrote:
> A more thorough review of the NFS write and flush logic that exists in
> 2.6.27 is needed if we choose to recognize this issue as a real
> problem.

Yep.  

Sorry.  I didn't mean we should revert the hunk.  I was just trying to
help identify the cause of the new behavior.

I think this is a real problem albeit not a "serious" one.  Network
file-systems usually try to avoid readers seeing blocks of zeros in
files, especially in this simple writer/reader case.

It wouldn't be bad if the file is written out of order occasionally, but
we see this constantly now.

We cannot write/read log files to NFS mounts reliably any more.  That
seems like a valid use case which no longer works?

Anyway, thanks for your time!

				=a=



-- 
===================
Aaron Straus
aaron@merfinllc.com

  reply	other threads:[~2008-09-11 17:19 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-05 19:19 [NFS] blocks of zeros (NULLs) in NFS files in kernels >= 2.6.20 Aaron Straus
2008-09-05 19:19 ` Aaron Straus
     [not found] ` <20080905191939.GG22796-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-05 19:56   ` [NFS] " Chuck Lever
2008-09-05 19:56     ` Chuck Lever
2008-09-05 20:04     ` Aaron Straus
2008-09-05 20:36       ` Bernd Eckenfels
     [not found]       ` <20080905200455.GH22796-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-05 20:36         ` Chuck Lever
2008-09-05 20:36           ` Chuck Lever
2008-09-05 22:14           ` Aaron Straus
2008-09-05 22:14             ` Aaron Straus
2008-09-06  0:03     ` Aaron Straus
2008-09-06  0:03       ` Aaron Straus
2008-09-08 19:02     ` Aaron Straus
2008-09-08 19:02       ` Aaron Straus
     [not found]       ` <20080908190212.GF28123-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-08 21:15         ` Chuck Lever
2008-09-08 21:15           ` Chuck Lever
     [not found]           ` <76bd70e30809081415h6b55a8dfl8171634c576ac946-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-09-08 22:02             ` Aaron Straus
2008-09-08 22:02               ` Aaron Straus
2008-09-09 19:46             ` Aaron Straus
2008-09-09 19:46               ` Aaron Straus
     [not found]               ` <20080909194644.GI5290-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-11 16:55                 ` Chuck Lever
2008-09-11 16:55                   ` Chuck Lever
2008-09-11 17:19                   ` Aaron Straus [this message]
2008-09-11 17:19                     ` Aaron Straus
     [not found]                     ` <20080911171908.GE12037-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-11 17:48                       ` Chuck Lever
2008-09-11 17:48                         ` Chuck Lever
2008-09-11 18:49                         ` Aaron Straus
2008-09-11 18:49                           ` Aaron Straus
     [not found]                           ` <20080911184951.GB19054-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-22 16:05                             ` Hans-Peter Jansen
2008-09-22 16:05                               ` Hans-Peter Jansen
     [not found]                               ` <200809221805.48463.hpj-2x7n3sizJbFeoWH0uzbU5w@public.gmane.org>
2008-09-22 16:35                                 ` Trond Myklebust
2008-09-22 16:35                                   ` Trond Myklebust
2008-09-22 17:04                                   ` Aaron Straus
2008-09-22 17:04                                     ` Aaron Straus
     [not found]                                     ` <20080922170414.GC12483-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-22 17:26                                       ` Chuck Lever
2008-09-22 17:26                                         ` Chuck Lever
     [not found]                                         ` <76bd70e30809221026g7bde774pbffa35881682ea4b-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2008-09-22 17:37                                           ` Aaron Straus
2008-09-22 17:37                                             ` Aaron Straus
2008-09-22 17:29                                       ` Trond Myklebust
2008-09-22 17:29                                         ` Trond Myklebust
2008-09-22 17:45                                         ` Aaron Straus
2008-09-22 17:45                                           ` Aaron Straus
     [not found]                                           ` <20080922174525.GF12483-bYFJunmd+ZV8UrSeD/g0lQ@public.gmane.org>
2008-09-22 18:43                                             ` Aaron Straus
2008-09-22 18:43                                               ` Aaron Straus
2008-09-22 18:45                                             ` Hans-Peter Jansen
2008-09-22 18:45                                               ` Hans-Peter Jansen
2008-09-22 18:45                                   ` Hans-Peter Jansen
2008-09-22 18:45                                     ` Hans-Peter Jansen

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