From manningc2@actrix.gen.nz Tue Apr 08 04:08:51 2008 Received: from smtp.firstline.co.nz ([203.167.210.162] helo=firstline.co.nz) by stoneboat.aleph1.co.uk with smtp (Exim 4.63) (envelope-from ) id 1Jj4CK-0005fw-6Y for yaffs@lists.aleph1.co.uk; Tue, 08 Apr 2008 04:08:51 +0100 Received: (qmail 7256 invoked by uid 453); 8 Apr 2008 03:08:23 -0000 X-Virus-Checked: Checked by ClamAV on firstline.co.nz Received: from Unknown (HELO [192.168.0.29]) (10.14.0.253) by firstline.co.nz (qpsmtpd/0.40) with ESMTP; Tue, 08 Apr 2008 15:08:23 +1200 From: Charles Manning To: yaffs@lists.aleph1.co.uk Date: Tue, 8 Apr 2008 15:08:22 +1200 User-Agent: KMail/1.9.6 References: <47F9C698.5060608@mizi.com> <200804081010.02409.manningc2@actrix.gen.nz> <47FAE05B.3050303@mizi.com> In-Reply-To: <47FAE05B.3050303@mizi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="euc-kr" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200804081508.22696.manningc2@actrix.gen.nz> X-SA-Exim-Connect-IP: 203.167.210.162 X-SA-Exim-Mail-From: manningc2@actrix.gen.nz X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on stoneboat.aleph1.co.uk X-Spam-Level: X-Spam-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_NEUTRAL autolearn=no version=3.2.3 X-SA-Exim-Version: 4.2.1 (built Tue, 09 Jan 2007 17:23:22 +0000) X-SA-Exim-Scanned: Yes (on stoneboat.aleph1.co.uk) Subject: Re: [Yaffs] mmap, power-off, and data is lost X-BeenThere: yaffs@lists.aleph1.co.uk X-Mailman-Version: 2.1.9 Precedence: list List-Id: Discussion of YAFFS NAND flash filesystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Apr 2008 03:08:51 -0000 On Tuesday 08 April 2008 15:02:51 Louis JANG wrote: > Hi Charles, > > Charles Manning =BE=B4 =B1=DB: > > On Monday 07 April 2008 19:00:40 Louis JANG wrote: > >> Hi all, > >> > >> I'm using yaffs in several mobile platform, and using mmap interface to > >> read/write contents of file in yaffs. it works well in normal situatio= n, > >> but it losts data when I turn off its power without unmount. > > > > With mmapping, the data lives in the page cache until it is flushed to > > the fs. > > > > YAFFS will not see the data until the mmapping is flushed through. This > > will only happen when the pages are sync'ed back to the fs by msync() = or > > when the page mapping is invalidated (page pushed out or munmap) > > > > As James says, msync should do what you need. > > I added msync before munmap, and data wasn't lost when I use MS_SYNC > flag. I also tried with MS_ASYNC and wait about more than 10 seconds, > but data was lost in this case. The thing to do here is to inspect the kernel code (VFS and mmap code) and= =20 determine what is actually happening during the MS_ASYNC case and munmap. It could be that yaffs needs to do something on munmap, but I would have=20 expected the kernel mmap code to flush pahes on the unmap. > > However, the sample code invalidated mmap area by munmap already, and > cached data should be flushed, but it wasn't. and I called sync command > in shell also. > > Regards, > Louis JANG > > > > _______________________________________________ > yaffs mailing list > yaffs@lists.aleph1.co.uk > http://lists.aleph1.co.uk/cgi-bin/mailman/listinfo/yaffs