From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pat LaVarre Subject: Re: zeroes read back more often than appended Date: 21 Oct 2003 12:44:54 -0600 Sender: linux-fsdevel-owner@vger.kernel.org Message-ID: <1066761894.3350.100.camel@patehci2> References: <1065553341.8172.45.camel@patehci2> <20031007204951.A25423@falcon.csc.calpoly.edu> <1065732882.5176.14.camel@patehci2> <1065747151.2314.12.camel@patehci2> <1065803984.3037.7.camel@patehci2> <1065809754.3037.105.camel@patehci2> <1066091916.3011.2.camel@patehci2> <1066096137.3314.32.camel@patehci2> <1066692050.2814.33.camel@patehci2> <1066747637.8228.7.camel@patehci2> <1066754816.12021.1.camel@patehci2> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from email-out1.iomega.com ([147.178.1.82]:57293 "EHLO email.iomega.com") by vger.kernel.org with ESMTP id S263281AbTJUSpE (ORCPT ); Tue, 21 Oct 2003 14:45:04 -0400 Received: from royntex01.iomegacorp.com (unknown [147.178.90.120]) by email.iomega.com (Postfix) with ESMTP id 9B4151913 for ; Tue, 21 Oct 2003 12:45:03 -0600 (MDT) To: linux-fsdevel@vger.kernel.org In-Reply-To: <1066754816.12021.1.camel@patehci2> List-Id: linux-fsdevel.vger.kernel.org Yes I can confirm. Try appending nonzero to multiple files in a round robin sequence, and udf.ko reads back zero in place of the nonzero written. mkfs in place of mkudffs reads back only the nonzero written. CONFIG_SMP is not set. CONFIG_PREEMPT is not set. I did tell dd to write all the backing store without skipping over any of it. Changing those variables does fix the "width x height" test case of one file, but not the "width x height x depth" test case of multiple files. In particular I tried: fswhd 0 768 mkudffs 0xFF600 0xC8 0x3 fswhd 0 768 mkudffs 0xFF600 0xC8 0x1 fswhd 0 768 mkudffs 0xFF600 0xC8 0x2 That sequence actually took down my kernel once, but for me that trouble did not repeat. I do not yet know where to go to begin learning how to see the dmesg leading up to an oops. oops kill my remote ssh. Pat LaVarre P.S. tty logs follow. Two files with mkudffs, reads zeroes from both files ouch. One file with mkudffs, ok because of CONFIG = PREEMPT = off. Two files with mkfs in place of mkudffs, ok. $ $ cd /mnt/hda11 $ $ fswhd 0 768 mkudffs 0xFF600 0xC8 0x2 Linux 2.6.0.8-udf i686 /mnt/hda11 dd if=/dev/zero of=dd.bin bs=1M seek=0 count=768 2>/dev/null -rw-rw-r-- 1 pat pat 805306368 Oct 21 11:49 dd.bin mkudffs 1.0.0b2 for UDF FS 1.0.0-cvs, 2002/02/09 0 hexdump -C whd0.bin | head -3 00000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| * 06fbe000 00 00 00 00 00 00 00 00 aa aa aa aa aa aa aa aa |................| hexdump -C whd1.bin | head -3 00000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| * 06ebb000 00 00 00 00 00 00 00 00 aa aa aa aa aa aa aa aa |................| +++ 2.dmesg 2003-10-21 11:50:13.486227568 -0600 + already set +UDF-fs DEBUG fs/udf/balloc.c:192:udf_bitmap_free_blocks: bit 15865 already set +UDF-fs DEBUG fs/udf/balloc.c:193:udf_bitmap_free_blocks: byte= 2 +UDF-fs DEBUG fs/udf/balloc.c:192:udf_bitmap_free_blocks: bit 15865 already set $ $ fswhd 0 768 mkudffs 0xFF600 0xC8 0x1 Linux 2.6.0.8-udf i686 /mnt/hda11 dd if=/dev/zero of=dd.bin bs=1M seek=0 count=768 2>/dev/null -rw-rw-r-- 1 pat pat 805306368 Oct 21 11:46 dd.bin mkudffs 1.0.0b2 for UDF FS 1.0.0-cvs, 2002/02/09 0 hexdump -C whd0.bin | head -3 00000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| * 0c783000 $ $ fswhd 0 768 mkfs 0xFF600 0xC8 0x2 Linux 2.6.0.8-udf i686 /mnt/hda11 dd if=/dev/zero of=dd.bin bs=1M seek=0 count=768 2>/dev/null -rw-rw-r-- 1 pat pat 805306368 Oct 21 11:52 dd.bin Usage: mkfs [-V] [-t fstype] [fs-options] device [size] mke2fs 1.32 (09-Nov-2002) 0 hexdump -C whd0.bin | head -3 00000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| * 0c783000 hexdump -C whd1.bin | head -3 00000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa |................| * 0c783000 $