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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 479B7C43461 for ; Tue, 15 Sep 2020 05:35:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C9E120756 for ; Tue, 15 Sep 2020 05:35:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726146AbgIOFfx (ORCPT ); Tue, 15 Sep 2020 01:35:53 -0400 Received: from mx2.suse.de ([195.135.220.15]:42984 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726131AbgIOFfv (ORCPT ); Tue, 15 Sep 2020 01:35:51 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 57B19AC98 for ; Tue, 15 Sep 2020 05:36:05 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v2 06/19] btrfs: don't allow tree block to cross page boundary for subpage support Date: Tue, 15 Sep 2020 13:35:19 +0800 Message-Id: <20200915053532.63279-7-wqu@suse.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915053532.63279-1-wqu@suse.com> References: <20200915053532.63279-1-wqu@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org As a preparation for subpage sector size support (allowing filesystem with sector size smaller than page size to be mounted) if the sector size is smaller than page size, we don't allow tree block to be read if it cross 64K(*) boundary. The 64K is selected because: - We are only going to support 64K page size for subpage - 64K is also the max node size btrfs supports This ensures that, tree blocks are always contained in one page for a system with 64K page size, which can greatly simplify the handling. Or we need to do complex multi-page handling for tree blocks. Currently the only way to create such tree blocks crossing 64K boundary is by btrfs-convert, which will get fixed soon and doesn't get wide-spread usage. Signed-off-by: Qu Wenruo --- fs/btrfs/extent_io.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index e56aa68cd9fe..9af972999a09 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5232,6 +5232,13 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, btrfs_err(fs_info, "bad tree block start %llu", start); return ERR_PTR(-EINVAL); } + if (fs_info->sectorsize < PAGE_SIZE && round_down(start, PAGE_SIZE) != + round_down(start + len - 1, PAGE_SIZE)) { + btrfs_err(fs_info, + "tree block crosses page boundary, start %llu nodesize %lu", + start, len); + return ERR_PTR(-EINVAL); + } eb = find_extent_buffer(fs_info, start); if (eb) -- 2.28.0