From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from hermes.rz.uni-sb.de (hermes.rz.uni-sb.de [134.96.7.3]) by kvack.org (8.8.7/8.8.7) with ESMTP id KAA10402 for ; Sat, 20 Mar 1999 10:33:41 -0500 Message-ID: <36F3BFDA.ED1B42B7@stud.uni-sb.de> Date: Sat, 20 Mar 1999 16:33:46 +0100 From: Manfred Spraul Reply-To: masp0008@stud.uni-sb.de MIME-Version: 1.0 Subject: Re: Possible optimization in ext2_file_write() References: <199903181816.XAA12650@vxindia.vxindia.veritas.com> <199903191448.OAA01416@dax.scot.redhat.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: "Stephen C. Tweedie" Cc: V Ganesh , linux-kernel@vger.rutgers.edu, linux-mm@kvack.org List-ID: "Stephen C. Tweedie" wrote: > > Hi, > > On Thu, 18 Mar 1999 23:46:57 +0530 (IST), V Ganesh > said: > > > it looks like whenever we write a partial block which > > doesn't exist in the buffer cache, ext2_file_write() (and > > possibly the write functions of other filesystems) directly > > reads that block from the block device without checking if > > it is present in the page cache. > > Correct... I don't know what you are exactly talking about, but there is another problem except speed: Most modern harddisks remap bad sectors, so sometimes you can't read a sector, but if you write the sector is remapped. I.e. if you "create a new file, write 400 bytes, close the file, sync", then the data sector should not be read. Our current Windows 95 & Windows NT file system drivers read the data sector, and that has caused problems (older ZIP disks, SyQuest, my own damnaged harddisk?-I don't remember the details). Regards, Manfred -- To unsubscribe, send a message with 'unsubscribe linux-mm my@address' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/