From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Kleikamp Subject: Re: [PATCH 10/13: eCryptfs] Mmap operations Date: Fri, 05 May 2006 10:22:28 -0500 Message-ID: <1146842548.10109.27.camel@kleikamp.austin.ibm.com> References: <84144f020605040813q29fcddcr1c846d27cf156432@mail.gmail.com> <20060504031755.GA28257@hellewell.homeip.net> <20060504034127.GI28613@hellewell.homeip.net> <23514.1146779003@warthog.cambridge.redhat.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Pekka Enberg , Phillip Hellewell , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk, mike@halcrow.us, mhalcrow@us.ibm.com, mcthomps@us.ibm.com, toml@us.ibm.com, yoder1@us.ibm.com, James Morris , "Stephen C. Tweedie" , Erez Zadok Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:5338 "EHLO e35.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751588AbWEEPWt (ORCPT ); Fri, 5 May 2006 11:22:49 -0400 To: David Howells In-Reply-To: <23514.1146779003@warthog.cambridge.redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, 2006-05-04 at 22:43 +0100, David Howells wrote: > Pekka Enberg wrote: > > > > + rc = mapping->a_ops->readpage(file, page); > > > > What's the purpose of this second read? > > When writing CacheFiles, I noticed that ext3 would occasionally unlock a page > that had neither PG_uptodate nor PG_error set, and so I had to force another > readpage() on it. I understand this comes from the FiST package. In that code, there is a comment in one of these functions explaining the second read. It would be nice to have that comment in here too: /* * call readpage() again if we returned from wait_on_page with a * page that's not up-to-date; that can happen when a partial * page has a few buffers which are ok, but not the whole * page. */ I'm a bit surprised that this could happen. Shaggy -- David Kleikamp IBM Linux Technology Center