From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [patch 1/2] mm: dont clear PG_uptodate in invalidate_complete_page2() Date: Wed, 25 Jun 2008 18:38:38 +0100 Message-ID: <20080625173837.GA10005@shareable.org> References: <20080625124038.103406301@szeredi.hu> <20080625124121.839734708@szeredi.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Miklos Szeredi , jens.axboe@oracle.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, hugh@veritas.com, nickpiggin@yahoo.com.au To: Linus Torvalds Return-path: Received: from mail2.shareable.org ([80.68.89.115]:50387 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752433AbYFYRio (ORCPT ); Wed, 25 Jun 2008 13:38:44 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Linus Torvalds wrote: > I also really don't think this even fixes the problems you have with > FUSE/NFSD - because you'll still be reading zeroes for a truncated file. > Yes, you get the rigth counts, but you don't get the right data. ... > That's "correct" from a splice() kind of standpoint (it's essentially a > temporary mmap() with MAP_PRIVATE), but the thing is, it just sounds like > the whole "page went away" thing is a more fundamental issue. It sounds > like nfds should hold a read-lock on the file while it has any IO in > flight, or something like that. I'm thinking any kind of user-space server using splice() will not want to transmit zeros either, when another process truncates the file. E.g. Apache, Samba, etc. Does this problem affect sendfile() users? -- Jamie