From patchwork Wed Oct 28 08:10:22 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chandan Rajendra X-Patchwork-Id: 7508181 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 899EB9F6E4 for ; Wed, 28 Oct 2015 08:11:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 94E05205DA for ; Wed, 28 Oct 2015 08:11:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F8E9205CA for ; Wed, 28 Oct 2015 08:11:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755668AbbJ1IL2 (ORCPT ); Wed, 28 Oct 2015 04:11:28 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:59537 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755678AbbJ1IKq (ORCPT ); Wed, 28 Oct 2015 04:10:46 -0400 Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 28 Oct 2015 13:40:41 +0530 X-Helo: d28dlp03.in.ibm.com X-MailFrom: chandan@linux.vnet.ibm.com X-RcptTo: linux-btrfs@vger.kernel.org Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id CA9C81258068 for ; Wed, 28 Oct 2015 13:40:35 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay02.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t9S8AdRR50069720 for ; Wed, 28 Oct 2015 13:40:39 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t9S8AaI4003535 for ; Wed, 28 Oct 2015 13:40:38 +0530 Received: from localhost.in.ibm.com ([9.124.35.170]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t9S8AZk4003373; Wed, 28 Oct 2015 13:40:36 +0530 From: Chandan Rajendra To: linux-btrfs@vger.kernel.org Cc: Chandan Rajendra , clm@fb.com, jbacik@fb.com, bo.li.liu@oracle.com, dsterba@suse.cz, quwenruo@cn.fujitsu.com, chandan@mykolab.com Subject: [PATCH V8 08/13] Btrfs: btrfs_submit_direct_hook: Handle map_length < bio vector length Date: Wed, 28 Oct 2015 13:40:22 +0530 Message-Id: <1446019827-685-9-git-send-email-chandan@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1446019827-685-1-git-send-email-chandan@linux.vnet.ibm.com> References: <1446019827-685-1-git-send-email-chandan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15102808-0017-0000-0000-0000081564DA Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In subpagesize-blocksize scenario, map_length can be less than the length of a bio vector. Such a condition may cause btrfs_submit_direct_hook() to submit a zero length bio. Fix this by comparing map_length against block size rather than with bv_len. Signed-off-by: Chandan Rajendra --- fs/btrfs/inode.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0dbeccb..cbb05d0 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8248,9 +8248,11 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, u64 file_offset = dip->logical_offset; u64 submit_len = 0; u64 map_length; - int nr_pages = 0; - int ret; + u32 blocksize = root->sectorsize; int async_submit = 0; + int nr_sectors; + int ret; + int i; map_length = orig_bio->bi_iter.bi_size; ret = btrfs_map_block(root->fs_info, rw, start_sector << 9, @@ -8280,9 +8282,12 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, atomic_inc(&dip->pending_bios); while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) { - if (map_length < submit_len + bvec->bv_len || - bio_add_page(bio, bvec->bv_page, bvec->bv_len, - bvec->bv_offset) < bvec->bv_len) { + nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len); + i = 0; +next_block: + if (unlikely(map_length < submit_len + blocksize || + bio_add_page(bio, bvec->bv_page, blocksize, + bvec->bv_offset + (i * blocksize)) < blocksize)) { /* * inc the count before we submit the bio so * we know the end IO handler won't happen before @@ -8303,7 +8308,6 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, file_offset += submit_len; submit_len = 0; - nr_pages = 0; bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS); @@ -8321,9 +8325,14 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip, bio_put(bio); goto out_err; } + + goto next_block; } else { - submit_len += bvec->bv_len; - nr_pages++; + submit_len += blocksize; + if (--nr_sectors) { + i++; + goto next_block; + } bvec++; } }