From patchwork Sun Oct 18 12:04:58 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chandan Rajendra X-Patchwork-Id: 7429921 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 5C6D8BEEA4 for ; Sun, 18 Oct 2015 12:06:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 85D74206EA for ; Sun, 18 Oct 2015 12:06:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BADB206E6 for ; Sun, 18 Oct 2015 12:06:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752898AbbJRMGg (ORCPT ); Sun, 18 Oct 2015 08:06:36 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:60748 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752843AbbJRMGc (ORCPT ); Sun, 18 Oct 2015 08:06:32 -0400 Received: from /spool/local by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Sun, 18 Oct 2015 22:06:28 +1000 X-Helo: d23dlp01.au.ibm.com X-MailFrom: chandan@linux.vnet.ibm.com X-RcptTo: linux-btrfs@vger.kernel.org Received: from d23relay10.au.ibm.com (d23relay10.au.ibm.com [9.190.26.77]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 6B1B42CE8050 for ; Sun, 18 Oct 2015 23:06:28 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t9IC6KPp60096524 for ; Sun, 18 Oct 2015 23:06:28 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t9IC5sfT029463 for ; Sun, 18 Oct 2015 23:05:56 +1100 Received: from localhost.in.ibm.com ([9.79.245.171]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t9IC5NV4028832; Sun, 18 Oct 2015 23:05:51 +1100 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 V6 08/13] Btrfs: btrfs_submit_direct_hook: Handle map_length < bio vector length Date: Sun, 18 Oct 2015 17:34:58 +0530 Message-Id: <1445169903-13915-9-git-send-email-chandan@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1445169903-13915-1-git-send-email-chandan@linux.vnet.ibm.com> References: <1445169903-13915-1-git-send-email-chandan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15101812-0013-0000-0000-0000020A9BF9 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, T_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 8a79e53..1826603 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8150,9 +8150,11 @@ 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, @@ -8182,9 +8184,12 @@ 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 @@ -8205,7 +8210,6 @@ 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); @@ -8223,9 +8227,14 @@ 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++; } }