Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751161AbWJWUjr (ORCPT ); Mon, 23 Oct 2006 16:39:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751298AbWJWUjr (ORCPT ); Mon, 23 Oct 2006 16:39:47 -0400 Received: from calculon.skynet.ie ([193.1.99.88]:58782 "EHLO calculon.skynet.ie") by vger.kernel.org with ESMTP id S1751161AbWJWUjq (ORCPT ); Mon, 23 Oct 2006 16:39:46 -0400 Date: Mon, 23 Oct 2006 21:39:44 +0100 To: Damien Wyart Cc: OGAWA Hirofumi , linux-kernel , Nick Piggin , Andrew Morton Subject: Re: 2.6.19-rc2-mm2 : empty files on vfat file system Message-ID: <20061023203944.GA17290@skynet.ie> References: <20061021104454.GA1996@localhost.localdomain> <87lkn9x0ly.fsf@duaron.myhome.or.jp> <20061021173849.GA1999@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20061021173849.GA1999@localhost.localdomain> User-Agent: Mutt/1.5.9i From: mel@skynet.ie (Mel Gorman) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2084 Lines: 46 On (21/10/06 19:38), Damien Wyart didst pronounce: > > > I have noticed something strange (and bad :) since using > > > 2.6.19-rc2-mm2 (the problem is NOT present on 2.6.19-rc2-mm1 ; do > > > not know for mainline, I have not been able to test yet, but I think > > > there have not been recent changes in this area) : writing a file to > > > a vfat fs (fat 32) writes it, but with size 0 and no content. > > * OGAWA Hirofumi [2006-10-21 22:24]: > > diff -puN fs/fat/inode.c~fs-prepare_write-fixes fs/fat/inode.c > > --- a/fs/fat/inode.c~fs-prepare_write-fixes > > +++ a/fs/fat/inode.c > > @@ -150,7 +150,11 @@ static int fat_commit_write(struct file > > unsigned from, unsigned to) > > { > > struct inode *inode = page->mapping->host; > > - int err = generic_commit_write(file, page, from, to); > > + int err; > > + if (to - from > 0) > > + return 0; > > + > > + err = generic_commit_write(file, page, from, to); > > if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { > > inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; > > MSDOS_I(inode)->i_attrs |= ATTR_ARCH; > > > This change does't update ->i_size. Could you just delete, and test > > it? Anyway, this seems wrong even if it's "if ((to - from) == 0)". > > Reverting the change makes the problem go away. But I do not know if > this is safe wrt the fs-prepare_write-fixes patch. > I don't know about the fix, but the issue is pretty serious for IA64 and the EFI bootloader. On the IA64 I have access to, the bootloader and related files are stored on a VFAT file system so when an automated system ran a simple boot-test, the bootloader was blown away as a result. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - 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/