From: jing zhang Subject: [PATCH] ext4: BUG_ON triggered in ext4_mb_complex_scan_group() Date: Mon, 5 Apr 2010 12:30:19 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: "Theodore Ts'o" , "Aneesh Kumar K. V" , Andreas Dilger , Dave Kleikamp To: linux-ext4 Return-path: Received: from mail-gw0-f46.google.com ([74.125.83.46]:53453 "EHLO mail-gw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732Ab0DEEaU (ORCPT ); Mon, 5 Apr 2010 00:30:20 -0400 Received: by gwb19 with SMTP id 19so1030021gwb.19 for ; Sun, 04 Apr 2010 21:30:19 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Jing Zhang Date: Mon Apr 5 12:10:50 2010 BUG_ON is triggered at [line:1762] in ext4_mb_complex_scan_group(), 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,