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=-5.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 19E48C2D0A3 for ; Fri, 6 Nov 2020 12:52:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 958ED206C1 for ; Fri, 6 Nov 2020 12:51:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="ZqAg/Ctl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727235AbgKFMv6 (ORCPT ); Fri, 6 Nov 2020 07:51:58 -0500 Received: from mx2.suse.de ([195.135.220.15]:33706 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726757AbgKFMv6 (ORCPT ); Fri, 6 Nov 2020 07:51:58 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604667116; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=ahvMiva3wO5sQyfgh8V5SiMQoNE7VEFY0/GlN29QTFI=; b=ZqAg/Ctlcq61EcDYVpgDoiSuQ52EZP6OmoFmatQlfVM6FSzx0nrxvVtCpKIgAUPgYu130T wRJiDhifp6hlAo/UPBFwPH7jNDADOibsoCQjs5t60V8cH7Qtf6SINlvExHYiHiZ4EOiG3D nuVQ9eDr/h3TFJj22y83LDKHOikTFyk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 56B01AB8F; Fri, 6 Nov 2020 12:51:56 +0000 (UTC) Subject: Re: [PATCH 19/32] btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To: Qu Wenruo , linux-btrfs@vger.kernel.org Cc: Goldwyn Rodrigues References: <20201103133108.148112-1-wqu@suse.com> <20201103133108.148112-20-wqu@suse.com> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: Date: Fri, 6 Nov 2020 14:51:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201103133108.148112-20-wqu@suse.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 3.11.20 г. 15:30 ч., Qu Wenruo wrote: > To support sectorsize < PAGE_SIZE case, we need to take extra care for > extent buffer accessors. > > Since sectorsize is smaller than PAGE_SIZE, one page can contain > multiple tree blocks, we must use eb->start to determine the real offset > to read/write for extent buffer accessors. > > This patch introduces two helpers to do these: > - get_eb_page_index() > This is to calculate the index to access extent_buffer::pages. > It's just a simple wrapper around "start >> PAGE_SHIFT". > > For sectorsize == PAGE_SIZE case, nothing is changed. > For sectorsize < PAGE_SIZE case, we always get index as 0, and > the existing page shift works also fine. > > - get_eb_page_offset() > This is to calculate the offset to access extent_buffer::pages. nit: This is the same sentence as for get_eb_page_index, I think you mean this calculates the offset in the page to start reading from. > This needs to take extent_buffer::start into consideration. > > For sectorsize == PAGE_SIZE case, extent_buffer::start is always > aligned to PAGE_SIZE, thus adding extent_buffer::start to > offset_in_page() won't change the result. > For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives > us the correct offset to access. > > This patch will touch the following parts to cover all extent buffer > accessors: > > - BTRFS_SETGET_HEADER_FUNCS() > - read_extent_buffer() > - read_extent_buffer_to_user() > - memcmp_extent_buffer() > - write_extent_buffer_chunk_tree_uuid() > - write_extent_buffer_fsid() > - write_extent_buffer() > - memzero_extent_buffer() > - copy_extent_buffer_full() > - copy_extent_buffer() > - memcpy_extent_buffer() > - memmove_extent_buffer() > - btrfs_get_token_##bits() > - btrfs_get_##bits() > - btrfs_set_token_##bits() > - btrfs_set_##bits() > - generic_bin_search() > > @@ -3314,6 +3315,39 @@ static inline void assertfail(const char *expr, const char* file, int line) { } > #define ASSERT(expr) (void)(expr) > #endif > > +/* > + * Get the correct offset inside the page of extent buffer. > + * > + * Will handle both sectorsize == PAGE_SIZE and sectorsize < PAGE_SIZE cases. > + * > + * @eb: The target extent buffer > + * @start: The offset inside the extent buffer > + */ > +static inline size_t get_eb_page_offset(const struct extent_buffer *eb, > + unsigned long offset_in_eb) nit: Rename to offset, you already pass an extent buffer so it's natural that the offset pertain to this eb. > +{ > + /* > + * For sectorsize == PAGE_SIZE case, eb->start will always be aligned > + * to PAGE_SIZE, thus adding it won't cause any difference. > + * > + * For sectorsize < PAGE_SIZE, we must only read the data belongs to > + * the eb, thus we have to take the eb->start into consideration. > + */ > + return offset_in_page(offset_in_eb + eb->start); > +} > + > +static inline unsigned long get_eb_page_index(unsigned long offset_in_eb) nit: Rename to offset since "in_eb" doesn't bring any value just makes the variable's name somewhat awkward. > +{ > + /* > + * For sectorsize == PAGE_SIZE case, plain >> PAGE_SHIFT is enough. > + * > + * For sectorsize < PAGE_SIZE case, we only support 64K PAGE_SIZE, > + * and has ensured all tree blocks are contained in one page, thus > + * we always get index == 0. > + */ > + return offset_in_eb >> PAGE_SHIFT; > +} > + > /* > * Use that for functions that are conditionally exported for sanity tests but > * otherwise static > @@ -5873,10 +5873,22 @@ void copy_extent_buffer_full(const struct extent_buffer *dst, > > ASSERT(dst->len == src->len); > > - num_pages = num_extent_pages(dst); > - for (i = 0; i < num_pages; i++) > - copy_page(page_address(dst->pages[i]), > - page_address(src->pages[i])); > + if (dst->fs_info->sectorsize == PAGE_SIZE) { > + num_pages = num_extent_pages(dst); > + for (i = 0; i < num_pages; i++) > + copy_page(page_address(dst->pages[i]), > + page_address(src->pages[i])); > + } else { > + unsigned long src_index = get_eb_page_index(0); > + unsigned long dst_index = get_eb_page_index(0); nit: unsigned long src_index = 0, dst_index = 0; and remove the ASSERT() below > + size_t src_offset = get_eb_page_offset(src, 0); > + size_t dst_offset = get_eb_page_offset(dst, 0); > + > + ASSERT(src_index == 0 && dst_index == 0); > + memcpy(page_address(dst->pages[dst_index]) + dst_offset, > + page_address(src->pages[src_index]) + src_offset, > + src->len); > + } > }