From patchwork Mon Dec 27 12:54:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jingbo Xu X-Patchwork-Id: 12699747 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38BE8C433F5 for ; Mon, 27 Dec 2021 12:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236890AbhL0MzI (ORCPT ); Mon, 27 Dec 2021 07:55:08 -0500 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:39581 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236868AbhL0MzC (ORCPT ); Mon, 27 Dec 2021 07:55:02 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0V.xJoRI_1640609699; Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0V.xJoRI_1640609699) by smtp.aliyun-inc.com(127.0.0.1); Mon, 27 Dec 2021 20:55:00 +0800 From: Jeffle Xu To: dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org Cc: linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org Subject: [PATCH v1 13/23] erofs: implement fscache-based data read Date: Mon, 27 Dec 2021 20:54:34 +0800 Message-Id: <20211227125444.21187-14-jefflexu@linux.alibaba.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211227125444.21187-1-jefflexu@linux.alibaba.com> References: <20211227125444.21187-1-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This patch implements the data plane of reading data from bootstrap blob file over fscache. Be noted that currently compressed layout is not supported yet. Signed-off-by: Jeffle Xu --- fs/erofs/fscache.c | 91 +++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/inode.c | 6 ++- fs/erofs/internal.h | 1 + 3 files changed, 97 insertions(+), 1 deletion(-) diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 325f5663836b..bfcec831d58a 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -65,6 +65,97 @@ struct page *erofs_readpage_from_fscache(struct erofs_cookie_ctx *ctx, return page; } +static inline void do_copy_page(struct page *from, struct page *to, + size_t offset, size_t len) +{ + char *vfrom, *vto; + + vfrom = kmap_atomic(from); + vto = kmap_atomic(to); + memcpy(vto, vfrom + offset, len); + kunmap_atomic(vto); + kunmap_atomic(vfrom); +} + +static int erofs_fscache_do_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + struct erofs_inode *vi = EROFS_I(inode); + struct super_block *sb = inode->i_sb; + struct erofs_map_blocks map; + erofs_off_t o_la, pa; + size_t offset, len; + struct page *ipage; + int ret; + + if (erofs_inode_is_data_compressed(vi->datalayout)) { + erofs_info(sb, "compressed layout not supported yet"); + return -EOPNOTSUPP; + } + + o_la = page_offset(page); + map.m_la = o_la; + + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW); + if (ret) + return ret; + + if (!(map.m_flags & EROFS_MAP_MAPPED)) { + zero_user(page, 0, PAGE_SIZE); + return 0; + } + + /* + * 1) For FLAT_PLAIN/FLAT_INLINE layout, the output map.m_la shall be + * equal to o_la, and the output map.m_pa is exactly the physical + * address of o_la. + * 2) For CHUNK_BASED layout, the output map.m_la is rounded down to the + * nearest chunk boundary, and the output map.m_pa is actually the + * physical address of this chunk boundary. So we need to recalculate + * the actual physical address of o_la. + */ + pa = map.m_pa + o_la - map.m_la; + + ipage = erofs_get_meta_page(sb, erofs_blknr(pa)); + if (IS_ERR(ipage)) + return PTR_ERR(ipage); + + /* + * @offset refers to the page offset inside @ipage. + * 1) Except for the inline layout, the offset shall all be 0, and @pa + * shall be aligned with EROFS_BLKSIZ in this case. Thus we can + * conveniently get the offset from @pa. + * 2) While for the inline layout, the offset may be non-zero. Since + * currently only flat layout supports inline, we can calculate the + * offset from the corresponding physical address. + */ + offset = erofs_blkoff(pa); + len = min_t(u64, map.m_llen, PAGE_SIZE); + + do_copy_page(ipage, page, offset, len); + + unlock_page(ipage); + return 0; +} + +static int erofs_fscache_readpage(struct file *file, struct page *page) +{ + int ret; + + ret = erofs_fscache_do_readpage(file, page); + if (ret) + SetPageError(page); + else + SetPageUptodate(page); + + unlock_page(page); + return ret; +} + +const struct address_space_operations erofs_fscache_access_aops = { + .readpage = erofs_fscache_readpage, +}; + static int erofs_fscache_init_cookie(struct erofs_cookie_ctx *ctx, char *path) { struct fscache_cookie *cookie; diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index 2345f1de438e..452d147277c4 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -299,7 +299,11 @@ static int erofs_fill_inode(struct inode *inode, int isdir) err = z_erofs_fill_inode(inode); goto out_unlock; } - inode->i_mapping->a_ops = &erofs_raw_access_aops; + + if (inode->i_sb->s_bdev) + inode->i_mapping->a_ops = &erofs_raw_access_aops; + else + inode->i_mapping->a_ops = &erofs_fscache_access_aops; out_unlock: unlock_page(page); diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 10fb7ef26ddf..f3a1aa429a93 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -357,6 +357,7 @@ struct page *erofs_grab_cache_page_nowait(struct address_space *mapping, extern const struct super_operations erofs_sops; extern const struct address_space_operations erofs_raw_access_aops; +extern const struct address_space_operations erofs_fscache_access_aops; extern const struct address_space_operations z_erofs_aops; /*