From patchwork Mon Dec 27 12:54:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jingbo Xu X-Patchwork-Id: 12699759 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 43F50C4332F for ; Mon, 27 Dec 2021 12:55:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237061AbhL0Mzn (ORCPT ); Mon, 27 Dec 2021 07:55:43 -0500 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:43159 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236849AbhL0MzB (ORCPT ); Mon, 27 Dec 2021 07:55:01 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0V.vxTJW_1640609698; Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0V.vxTJW_1640609698) by smtp.aliyun-inc.com(127.0.0.1); Mon, 27 Dec 2021 20:54:59 +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 12/23] erofs: implement fscache-based metadata read Date: Mon, 27 Dec 2021 20:54:33 +0800 Message-Id: <20211227125444.21187-13-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 metadata from bootstrap blob file over fscache. Be noted that currently it only supports the scenario where the backing file has no hole. Once it hits a hole of the backing file, erofs will fail the IO with -EOPNOTSUPP for now. The following patch will fix this issue, i.e. implementing the demand reading mode. Signed-off-by: Jeffle Xu Reported-by: kernel test robot Reported-by: kernel test robot --- fs/erofs/data.c | 4 +-- fs/erofs/fscache.c | 59 +++++++++++++++++++++++++++++++++++++++++++++ fs/erofs/internal.h | 3 +++ fs/erofs/super.c | 7 ++---- 4 files changed, 66 insertions(+), 7 deletions(-) diff --git a/fs/erofs/data.c b/fs/erofs/data.c index 61fa431d0713..f0857c285fac 100644 --- a/fs/erofs/data.c +++ b/fs/erofs/data.c @@ -19,8 +19,8 @@ struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr) page = read_cache_page_gfp(mapping, blkaddr, mapping_gfp_constraint(mapping, ~__GFP_FS)); } else { - /* TODO: data path in nodev mode */ - page = ERR_PTR(-EINVAL); + page = erofs_readpage_from_fscache(EROFS_SB(sb)->bootstrap, + blkaddr); } /* should already be PageUptodate */ diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 4dfca7c95710..325f5663836b 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -6,6 +6,65 @@ static struct fscache_volume *volume; +static int erofs_begin_cache_operation(struct netfs_read_request *rreq) +{ + return fscache_begin_read_operation(&rreq->cache_resources, + rreq->netfs_priv); +} + +static void erofs_priv_cleanup(struct address_space *mapping, void *netfs_priv) +{ +} + +static void erofs_issue_op(struct netfs_read_subrequest *subreq) +{ + /* + * TODO: implement demand-read logic later. + * We rely on user daemon to prepare blob files under corresponding + * directory, and we can reach here if blob files don't exist. + */ + + netfs_subreq_terminated(subreq, -EOPNOTSUPP, false); +} + +const struct netfs_read_request_ops erofs_req_ops = { + .begin_cache_operation = erofs_begin_cache_operation, + .cleanup = erofs_priv_cleanup, + .issue_op = erofs_issue_op, +}; + +struct page *erofs_readpage_from_fscache(struct erofs_cookie_ctx *ctx, + pgoff_t index) +{ + struct folio *folio; + struct page *page; + struct super_block *sb = ctx->inode->i_sb; + int ret; + + page = find_or_create_page(ctx->inode->i_mapping, index, GFP_KERNEL); + if (unlikely(!page)) { + erofs_err(sb, "failed to allocate page"); + return ERR_PTR(-ENOMEM); + } + + /* The content is already buffered in the address space */ + if (PageUptodate(page)) { + unlock_page(page); + return page; + } + + /* Or a new page cache is created, then read the content from fscache */ + folio = page_folio(page); + + ret = netfs_readpage(NULL, folio, &erofs_req_ops, ctx->cookie); + if (unlikely(ret || !PageUptodate(page))) { + erofs_err(sb, "failed to read from fscache"); + return ERR_PTR(-EINVAL); + } + + return page; +} + static int erofs_fscache_init_cookie(struct erofs_cookie_ctx *ctx, char *path) { struct fscache_cookie *cookie; diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 4ee4ff6774ba..10fb7ef26ddf 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -585,6 +585,9 @@ struct erofs_cookie_ctx *erofs_fscache_get_ctx(struct super_block *sb, char *path); void erofs_fscache_put_ctx(struct erofs_cookie_ctx *ctx); +struct page *erofs_readpage_from_fscache(struct erofs_cookie_ctx *ctx, + pgoff_t index); + #define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */ #endif /* __EROFS_INTERNAL_H */ diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 141cabd01d32..0e5964d8b24b 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -334,25 +334,22 @@ static int erofs_init_devices(struct super_block *sb, static int erofs_read_superblock(struct super_block *sb) { - struct erofs_sb_info *sbi; + struct erofs_sb_info *sbi = EROFS_SB(sb); struct page *page; struct erofs_super_block *dsb; unsigned int blkszbits; void *data; int ret; - /* TODO: metadata path in nodev mode */ if (sb->s_bdev) page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL); else - page = ERR_PTR(-EOPNOTSUPP); + page = erofs_readpage_from_fscache(sbi->bootstrap, 0); if (IS_ERR(page)) { erofs_err(sb, "cannot read erofs superblock"); return PTR_ERR(page); } - sbi = EROFS_SB(sb); - data = kmap(page); dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);