Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751419AbWE2VkV (ORCPT ); Mon, 29 May 2006 17:40:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751427AbWE2VkU (ORCPT ); Mon, 29 May 2006 17:40:20 -0400 Received: from ns2.suse.de ([195.135.220.15]:48058 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1751424AbWE2VkO (ORCPT ); Mon, 29 May 2006 17:40:14 -0400 Date: Mon, 29 May 2006 23:40:11 +0200 From: Olaf Hering To: linux-kernel@vger.kernel.org Subject: cramfs corruption after BLKFLSBUF on loop device Message-ID: <20060529214011.GA417@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-DOS: I got your 640K Real Mode Right Here Buddy! X-Homeland-Security: You are not supposed to read this line! You are a terrorist! User-Agent: Mutt und vi sind doch schneller als Notes (und GroupWise) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1894 Lines: 46 This script will cause cramfs decompression errors, on SMP at least: #!/bin/bash while :;do blockdev --flushbufs /dev/loop0;done /dev/null& while :;do ps faxs /dev/null&done /dev/null& while :;do dmesg /dev/null&done /dev/null& while :;do find /mounts/instsys -type f -print0|xargs -0 cat &>/dev/null;done ... Error -3 while decompressing! c0000000009592a2(2649)->c0000000edf87000(4096) Error -3 while decompressing! c000000000959298(2520)->c0000000edbc7000(4096) Error -3 while decompressing! c000000000959c70(2489)->c0000000f1482000(4096) Error -3 while decompressing! c00000000095a629(2355)->c0000000edaff000(4096) Error -3 while decompressing! ... evms_access does the ioctl (lots of them) on the loop device. Its a long standing bug, 2.6.5 fails as well. cramfs_read() clears parts of the src buffer because the page is not uptodate. invalidate_bdev() touched the page last. cramfs_read() was called from line 480 or 490 when the PageUptodate(page) test fails. ... 464 static int cramfs_readpage(struct file *file, struct page * page) .. 479 if (page->index) 480 start_offset = *(u32 *) cramfs_read(sb, blkptr_offset-4, 4); .. 488 bytes_filled = cramfs_uncompress_block(pgdata, 489 PAGE_CACHE_SIZE, 490 cramfs_read(sb, start_offset, compr_len), 491 compr_len); ... There are rumors that cramfs is not smp safe... Maybe the only hope is to tell evms to not do that ioctl for loop. - 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/