From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: reiserfs and SCSI oops seen in 2.6.9-rc2 with local SCSI disk IO Date: Mon, 04 Oct 2004 20:45:03 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1096937103.6679.4.camel@watt.suse.com> References: <4154372C.7070506@netapp.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from cantor.suse.de ([195.135.220.2]:5763 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S268729AbUJEAqD (ORCPT ); Mon, 4 Oct 2004 20:46:03 -0400 In-Reply-To: <4154372C.7070506@netapp.com> List-Id: linux-scsi@vger.kernel.org To: David Wysochanski , akpm@osdl.org Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org On Fri, 2004-09-24 at 11:03 -0400, David Wysochanski wrote: > I can reproduce this pretty easily with local disk. > > Here's some details about my setup (attached is the > full kernel config): > - dell 2650 (dual xeon, hyperthreading disabled) > - 1 local SCSI disk (root volume) > - 2 local SCSI disks (data), each with 10 partitions > of 100MB each, 6 of them reiserfs filesystems, 3 of them > ext3, and 3 of them ext2 (total of 20 unique filesystems) > - one instance of test program running on each of the > 20 filesystems > > Sorry, but at this time I can't share the test program itself > (I'm working on that). Let me try to describe it though. I think this is a bug in how reiserfs deals with small filesystems. There are a few different cases where it will try to use bitmap #2 even when there is only 1 bitmap. Each of your test filesystems will need only 1 bitmap for reiserfs, so while it is a valid bug, it's not the one you were originally trying to reproduce. This patch should do it (against 2.6.9-rc3). Thanks to Jan Kara for finding this bug. -chris On small filesystems (<128M), make sure not to reference bitmap blocks that don't exist. Index: linux.269rc3/fs/reiserfs/bitmap.c =================================================================== --- linux.269rc3.orig/fs/reiserfs/bitmap.c 2004-08-18 09:38:50.000000000 -0400 +++ linux.269rc3/fs/reiserfs/bitmap.c 2004-10-04 20:19:42.000000000 -0400 @@ -236,6 +236,9 @@ static int bmap_hash_id(struct super_blo if (!bm) bm = 1; } + /* this can only be true when SB_BMAP_NR = 1 */ + if (bm >= SB_BMAP_NR(s)) + bm = 0; return bm; } @@ -293,6 +296,10 @@ static int scan_bitmap (struct reiserfs_ get_bit_address (s, *start, &bm, &off); get_bit_address (s, finish, &end_bm, &end_off); + if (bm > SB_BMAP_NR(s)) + return 0; + if (end_bm > SB_BMAP_NR(s)) + end_bm = SB_BMAP_NR(s); /* When the bitmap is more than 10% free, anyone can allocate. * When it's less than 10% free, only files that already use the @@ -313,6 +320,7 @@ static int scan_bitmap (struct reiserfs_ if (nr_allocated) goto ret; } + /* we know from above that start is a reasonable number */ get_bit_address (s, *start, &bm, &off); } @@ -1050,9 +1058,10 @@ int reiserfs_allocate_blocknrs(reiserfs_ { int initial_amount_needed = amount_needed; int ret; + struct super_block *s = hint->th->t_super; /* Check if there is enough space, taking into account reserved space */ - if ( SB_FREE_BLOCKS(hint->th->t_super) - REISERFS_SB(hint->th->t_super)->reserved_blocks < + if ( SB_FREE_BLOCKS(s) - REISERFS_SB(s)->reserved_blocks < amount_needed - reserved_by_us) return NO_DISK_SPACE; /* should this be if !hint->inode && hint->preallocate? */ @@ -1072,6 +1081,8 @@ int reiserfs_allocate_blocknrs(reiserfs_ /* find search start and save it in hint structure */ determine_search_start(hint, amount_needed); + if (hint->search_start >= SB_BLOCK_COUNT(s)) + hint->search_start = SB_BLOCK_COUNT(s) - 1; /* allocation itself; fill new_blocknrs and preallocation arrays */ ret = blocknrs_and_prealloc_arrays_from_search_start