From patchwork Fri May 20 04:44:58 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 9129831 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 84F376048B for ; Fri, 20 May 2016 15:08:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7778121BED for ; Fri, 20 May 2016 15:08:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6C4E227BE4; Fri, 20 May 2016 15:08:48 +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=-5.4 required=2.0 tests=BAYES_00, DATE_IN_PAST_06_12, 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 5E4B622067 for ; Fri, 20 May 2016 15:08:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756011AbcETPIm (ORCPT ); Fri, 20 May 2016 11:08:42 -0400 Received: from mail.kernel.org ([198.145.29.136]:42715 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755843AbcETPIk (ORCPT ); Fri, 20 May 2016 11:08:40 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C307420364 for ; Fri, 20 May 2016 15:08:38 +0000 (UTC) Received: from debian3.lan (bl12-226-64.dsl.telepac.pt [85.245.226.64]) (using TLSv1.2 with cipher AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9EC802012D for ; Fri, 20 May 2016 15:08:37 +0000 (UTC) From: fdmanana@kernel.org To: linux-btrfs@vger.kernel.org Subject: [PATCH 4/6] Btrfs: fix unprotected assignment of the left cursor for device replace Date: Fri, 20 May 2016 05:44:58 +0100 Message-Id: <1463719498-2057-1-git-send-email-fdmanana@kernel.org> X-Mailer: git-send-email 2.7.0.rc3 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Filipe Manana We were assigning new values to fields of the device replace object without holding the respective lock after processing each device extent. This is important for the left cursor field which can be accessed by a concurrent task running __btrfs_map_block (which, correctly, takes the device replace lock). So change these fields while holding the device replace lock. Signed-off-by: Filipe Manana Reviewed-by: Josef Bacik --- fs/btrfs/scrub.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index a181b52..a58e0ae 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3640,9 +3640,11 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, break; } + btrfs_dev_replace_lock(&fs_info->dev_replace, 1); dev_replace->cursor_right = found_key.offset + length; dev_replace->cursor_left = found_key.offset; dev_replace->item_needs_writeback = 1; + btrfs_dev_replace_unlock(&fs_info->dev_replace, 1); ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length, found_key.offset, cache, is_dev_replace); @@ -3716,8 +3718,10 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx, break; } + btrfs_dev_replace_lock(&fs_info->dev_replace, 1); dev_replace->cursor_left = dev_replace->cursor_right; dev_replace->item_needs_writeback = 1; + btrfs_dev_replace_unlock(&fs_info->dev_replace, 1); skip: key.offset = found_key.offset + length; btrfs_release_path(path);