From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A4F3C64E7A for ; Tue, 1 Dec 2020 18:09:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B0FC2206D5 for ; Tue, 1 Dec 2020 18:09:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="EaiM0siA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404280AbgLASJb (ORCPT ); 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <29f468ffe7b19dbebae2201f10307ec4f34f1c88.1606834393.git.josef@toxicpanda.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 1.12.20 г. 16:53 ч., Josef Bacik wrote: > While doing error injection I would sometimes get a corrupt file system. > This is because I was injecting errors at btrfs_search_slot, but would > only do it one time per stack. This uncovered a problem in > commit_fs_roots, where if we get an error we would just break. However > we're in a second loop, the first loop being a loop to find all the nit: s/second/nested as initially I go confused about us being in a 2nd loop iteration. Using nested makes it a bit clearer > dirty fs roots, and then subsequent root updates would succeed clearing > the error value. > > This isn't likely to happen in real scenarios, however we could > potentially get a random ENOMEM once and then not again, and we'd end up > with a corrupted file system. Fix this by moving the error checking > around a bit to the main loop, as this is the only place where something > will fail, and return the error as soon as it occurs. > > With this patch my reproducer no longer corrupts the file system. > > Signed-off-by: Josef Bacik > --- > fs/btrfs/transaction.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c > index 1dac76b7ea96..b05f75654b16 100644 > --- a/fs/btrfs/transaction.c > +++ b/fs/btrfs/transaction.c > @@ -1328,7 +1328,6 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) > struct btrfs_root *gang[8]; > int i; > int ret; > - int err = 0; > > spin_lock(&fs_info->fs_roots_radix_lock); > while (1) { > @@ -1340,6 +1339,8 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) > break; > for (i = 0; i < ret; i++) { > struct btrfs_root *root = gang[i]; > + int err; > + > radix_tree_tag_clear(&fs_info->fs_roots_radix, > (unsigned long)root->root_key.objectid, > BTRFS_ROOT_TRANS_TAG); > @@ -1366,14 +1367,14 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans) > err = btrfs_update_root(trans, fs_info->tree_root, > &root->root_key, > &root->root_item); > - spin_lock(&fs_info->fs_roots_radix_lock); > if (err) > - break; > + return err; > + spin_lock(&fs_info->fs_roots_radix_lock); > btrfs_qgroup_free_meta_all_pertrans(root); > } > } > spin_unlock(&fs_info->fs_roots_radix_lock); > - return err; > + return 0; > } > > /* >