From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:51869 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbcFWB2k (ORCPT ); Wed, 22 Jun 2016 21:28:40 -0400 Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u5N1SeM5012667 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 23 Jun 2016 01:28:40 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0022.oracle.com (8.14.4/8.13.8) with ESMTP id u5N1Sdtd004283 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 23 Jun 2016 01:28:39 GMT Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by aserv0122.oracle.com (8.13.8/8.13.8) with ESMTP id u5N1Sbtu023207 for ; Thu, 23 Jun 2016 01:28:38 GMT From: Liu Bo To: linux-btrfs@vger.kernel.org Subject: [PATCH] Btrfs: cleanup BUG_ON in merge_bio Date: Wed, 22 Jun 2016 18:31:49 -0700 Message-Id: <1466645509-26910-1-git-send-email-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: One can use btrfs-corrupt-block to hit BUG_ON() in merge_bio(), thus this aims to stop anyone to panic the whole system by using their btrfs. Since the error in merge_bio can only come from __btrfs_map_block() when chunk tree mapping has something insane and __btrfs_map_block() has already had printed the reason, we can just return errors in merge_bio. Signed-off-by: Liu Bo --- fs/btrfs/extent_io.c | 1 - fs/btrfs/inode.c | 8 ++++++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index aa44d3e..a8661fb 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2756,7 +2756,6 @@ static int merge_bio(int rw, struct extent_io_tree *tree, struct page *page, if (tree->ops && tree->ops->merge_bio_hook) ret = tree->ops->merge_bio_hook(rw, page, offset, size, bio, bio_flags); - BUG_ON(ret < 0); return ret; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 8b1212e..d203c06 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1822,6 +1822,10 @@ static void btrfs_clear_bit_hook(struct inode *inode, /* * extent_io.c merge_bio_hook, this must check the chunk tree to make sure * we don't create bios that span stripes or chunks + * + * return 1 if page cannot be merged to bio + * return 0 if page can be merged to bio + * return error otherwise */ int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset, size_t size, struct bio *bio, @@ -1840,8 +1844,8 @@ int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset, map_length = length; ret = btrfs_map_block(root->fs_info, rw, logical, &map_length, NULL, 0); - /* Will always return 0 with map_multi == NULL */ - BUG_ON(ret < 0); + if (ret < 0) + return ret; if (map_length < length + size) return 1; return 0; -- 2.5.5