From patchwork Thu May 11 16:50:22 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9722587 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 784AF60387 for ; Thu, 11 May 2017 16:50:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6DB7C286BD for ; Thu, 11 May 2017 16:50:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 62791286D6; Thu, 11 May 2017 16:50:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C0CD286E7 for ; Thu, 11 May 2017 16:50:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932621AbdEKQue (ORCPT ); Thu, 11 May 2017 12:50:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:34510 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757970AbdEKQue (ORCPT ); Thu, 11 May 2017 12:50:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8BAE9ACBE; Thu, 11 May 2017 16:50:32 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 3D12F1E11BB; Thu, 11 May 2017 18:50:32 +0200 (CEST) From: Jan Kara To: "Darrick J . Wong" Cc: , Jan Kara , stable@vger.kernel.org Subject: [PATCH 1/2] xfs: Fix missed holes in SEEK_HOLE implementation Date: Thu, 11 May 2017 18:50:22 +0200 Message-Id: <20170511165023.29887-1-jack@suse.cz> X-Mailer: git-send-email 2.12.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP XFS SEEK_HOLE implementation could miss a hole in an unwritten extent as can be seen by the following command: xfs_io -c "falloc 0 256k" -c "pwrite 0 56k" -c "pwrite 128k 8k" -c "seek -h 0" file wrote 57344/57344 bytes at offset 0 56 KiB, 14 ops; 0.0000 sec (49.312 MiB/sec and 12623.9856 ops/sec) wrote 8192/8192 bytes at offset 131072 8 KiB, 2 ops; 0.0000 sec (70.383 MiB/sec and 18018.0180 ops/sec) Whence Result HOLE 139264 Where we can see that hole at offset 56k was just ignored by SEEK_HOLE implementation. The bug is in xfs_find_get_desired_pgoff() which does not properly detect the case when a first page in the pagevec has larger index than expected (and even if the condition was right, we would fail to update the returned offset). Fix the problem by properly detecting when found page has larger offset than expected. CC: stable@vger.kernel.org Fixes: d126d43f631f996daeee5006714fed914be32368 Signed-off-by: Jan Kara Reviewed-by: Darrick J. Wong --- fs/xfs/xfs_file.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 35703a801372..df51c025adfe 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1077,13 +1077,12 @@ xfs_find_get_desired_pgoff( } /* - * At lease we found one page. If this is the first time we - * step into the loop, and if the first page index offset is - * greater than the given search offset, a hole was found. + * At least we found one page. If the current offset is smaller + * than the first page offset, a hole was found. */ - if (type == HOLE_OFF && lastoff == startoff && - lastoff < page_offset(pvec.pages[0])) { + if (type == HOLE_OFF && lastoff < page_offset(pvec.pages[0])) { found = true; + *offset = lastoff; break; }