From: Eric Sandeen Subject: Re: [PATCH] ext4: BUG_ON triggered in ext4_mb_complex_scan_group() Date: Sun, 04 Apr 2010 23:36:06 -0500 Message-ID: <4BB968B6.1060005@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4 , "Theodore Ts'o" , "Aneesh Kumar K. V" , Andreas Dilger , Dave Kleikamp To: jing zhang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:15644 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749Ab0DEEgR (ORCPT ); Mon, 5 Apr 2010 00:36:17 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: jing zhang wrote: > From: Jing Zhang > > Date: Mon Apr 5 12:10:50 2010 > > BUG_ON is triggered at [line:1762] in ext4_mb_complex_scan_group(), Do you have a test case which can trigger this BUG_ON? -Eric > and fix is to change the return value of mb_find_extent() if the > needed extent can not be found. The fix can also be applied to other > points where mb_find_extent() is called. > > Cc: Theodore Ts'o > Cc: Andreas Dilger > Cc: Dave Kleikamp > Cc: "Aneesh Kumar K. V" > Signed-off-by: Jing Zhang > --- > fs/ext4/mballoc.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index bba1282..fbb6899 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -1321,7 +1321,7 @@ static int mb_find_extent(struct ext4_buddy > *e4b, int order, int block, > ex->fe_len = 0; > ex->fe_start = 0; > ex->fe_group = 0; > - return 0; > + return -ENOSPC; > } > > /* FIXME dorp order completely ? */ > @@ -1358,6 +1358,8 @@ static int mb_find_extent(struct ext4_buddy > *e4b, int order, int block, > } > > BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3))); > + if (needed > ex->fe_len) > + return -ENOSPC; > return ex->fe_len; > } > > @@ -1758,7 +1760,8 @@ void ext4_mb_complex_scan_group(struct > ext4_allocation_context *ac, > break; > } > > - mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex); > + if (0 > mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex)) > + break; > BUG_ON(ex.fe_len <= 0); > if (free < ex.fe_len) { > ext4_grp_locked_error(sb, e4b->bd_group, > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html