From patchwork Thu Jan 27 16:02:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12726978 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 A76ECC4332F for ; Thu, 27 Jan 2022 16:03:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234765AbiA0QDM (ORCPT ); Thu, 27 Jan 2022 11:03:12 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32175 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243116AbiA0QDI (ORCPT ); Thu, 27 Jan 2022 11:03:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643299388; 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; bh=4ZL9XkCQu7wUBYOqBR+5ICE3qgGhVimK2dNlAPGnydc=; b=MrCMkiG+EIimhnFVIKD+ivCnxwbg/I12hdCCYhiDcsrVTcmHwojJCsdl5DvznlqIn6RDwD 84cARVBlwBHZzkV27PwiDw3dYzSuSmMC2dPxgQc7mUpvGAGBKvmgWsxuMI907eU2lOjSXK dPqtg8+h5bYfw/WmvjiQ8NQIcufIUYM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-100-iimi_g4iNTWrIlX10fhqZA-1; Thu, 27 Jan 2022 11:03:02 -0500 X-MC-Unique: iimi_g4iNTWrIlX10fhqZA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 56E2F814249; Thu, 27 Jan 2022 16:03:01 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 34D1922DEF; Thu, 27 Jan 2022 16:02:59 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 4/4] cifs: Implement cache I/O by accessing the cache directly From: David Howells To: Steve French Cc: Shyam Prasad N , linux-cifs@vger.kernel.org, linux-cachefs@redhat.com, dhowells@redhat.com, Shyam Prasad N , Jeff Layton , Matthew Wilcox , Linus Torvalds , linux-cifs@vger.kernel.org, linux-cachefs@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 27 Jan 2022 16:02:58 +0000 Message-ID: <164329937835.843658.13129382687019174242.stgit@warthog.procyon.org.uk> In-Reply-To: <164329930161.843658.7387773437540491743.stgit@warthog.procyon.org.uk> References: <164329930161.843658.7387773437540491743.stgit@warthog.procyon.org.uk> User-Agent: StGit/1.4 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Move cifs to using fscache DIO API instead of the old upstream I/O API as that has been removed. This is a stopgap solution as the intention is that at sometime in the future, the cache will move to using larger blocks and won't be able to store individual pages in order to deal with the potential for data corruption due to the backing filesystem being able insert/remove bridging blocks of zeros into its extent list[1]. cifs then reads and writes cache pages synchronously and one page at a time. The preferred change would be to use the netfs lib, but the new I/O API can be used directly. It's just that as the cache now needs to track data for itself, caching blocks may exceed page size... This code is somewhat borrowed from my "fallback I/O" patchset[2]. Signed-off-by: David Howells cc: Steve French cc: Shyam Prasad N cc: linux-cifs@vger.kernel.org cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/YO17ZNOcq+9PajfQ@mit.edu [1] Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2] --- fs/cifs/file.c | 55 +++++++++++++++++++++-- fs/cifs/fscache.c | 126 +++++++++++++++++++++++++++++++++++++++++++++-------- fs/cifs/fscache.h | 79 +++++++++++++++++++++------------ 3 files changed, 207 insertions(+), 53 deletions(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index be62dc29dc54..1b41b6f2a04b 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4276,12 +4276,12 @@ cifs_readv_complete(struct work_struct *work) } else SetPageError(page); - unlock_page(page); - if (rdata->result == 0 || (rdata->result == -EAGAIN && got_bytes)) cifs_readpage_to_fscache(rdata->mapping->host, page); + unlock_page(page); + got_bytes -= min_t(unsigned int, PAGE_SIZE, got_bytes); put_page(page); @@ -4396,7 +4396,11 @@ static void cifs_readahead(struct readahead_control *ractl) struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(ractl->file); struct TCP_Server_Info *server; pid_t pid; - unsigned int xid, last_batch_size = 0; + unsigned int xid, nr_pages, last_batch_size = 0, cache_nr_pages = 0; + pgoff_t next_cached = ULONG_MAX; + bool caching = fscache_cookie_enabled(cifs_inode_cookie(ractl->mapping->host)) && + cifs_inode_cookie(ractl->mapping->host)->cache_priv; + bool check_cache = caching; xid = get_xid(); @@ -4414,12 +4418,52 @@ static void cifs_readahead(struct readahead_control *ractl) /* * Chop the readahead request up into rsize-sized read requests. */ - while (readahead_count(ractl) - last_batch_size) { - unsigned int i, nr_pages, got, rsize; + while ((nr_pages = readahead_count(ractl) - last_batch_size)) { + unsigned int i, got, rsize; struct page *page; struct cifs_readdata *rdata; struct cifs_credits credits_on_stack; struct cifs_credits *credits = &credits_on_stack; + pgoff_t index = readahead_index(ractl) + last_batch_size; + + /* + * Find out if we have anything cached in the range of + * interest, and if so, where the next chunk of cached data is. + */ + if (caching) { + if (check_cache) { + rc = cifs_fscache_query_occupancy( + ractl->mapping->host, index, nr_pages, + &next_cached, &cache_nr_pages); + if (rc < 0) + caching = false; + check_cache = false; + } + + if (index == next_cached) { + /* + * TODO: Send a whole batch of pages to be read + * by the cache. + */ + page = readahead_page(ractl); + BUG_ON(!page); + if (cifs_readpage_from_fscache(ractl->mapping->host, + page) < 0) { + /* + * TODO: Deal with cache read failure + * here, but for the moment, delegate + * that to readpage. + */ + caching = false; + } + unlock_page(page); + next_cached++; + cache_nr_pages--; + if (cache_nr_pages == 0) + check_cache = true; + continue; + } + } if (open_file->invalidHandle) { rc = cifs_reopen_file(open_file, true); @@ -4435,6 +4479,7 @@ static void cifs_readahead(struct readahead_control *ractl) if (rc) break; nr_pages = min_t(size_t, rsize / PAGE_SIZE, readahead_count(ractl)); + nr_pages = min_t(size_t, nr_pages, next_cached - index); /* * Give up immediately if rsize is too small to read an entire diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c index efaac4d5ff55..f98cfcc0d397 100644 --- a/fs/cifs/fscache.c +++ b/fs/cifs/fscache.c @@ -134,37 +134,127 @@ void cifs_fscache_release_inode_cookie(struct inode *inode) } } +static inline void fscache_end_operation(struct netfs_cache_resources *cres) +{ + const struct netfs_cache_ops *ops = fscache_operation_valid(cres); + + if (ops) + ops->end_operation(cres); +} + /* - * Retrieve a page from FS-Cache + * Fallback page reading interface. */ -int __cifs_readpage_from_fscache(struct inode *inode, struct page *page) +static int fscache_fallback_read_page(struct inode *inode, struct page *page) { - cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n", - __func__, CIFS_I(inode)->fscache, page, inode); - return -ENOBUFS; // Needs conversion to using netfslib + struct netfs_cache_resources cres; + struct fscache_cookie *cookie = cifs_inode_cookie(inode); + struct iov_iter iter; + struct bio_vec bvec[1]; + int ret; + + memset(&cres, 0, sizeof(cres)); + bvec[0].bv_page = page; + bvec[0].bv_offset = 0; + bvec[0].bv_len = PAGE_SIZE; + iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE); + + ret = fscache_begin_read_operation(&cres, cookie); + if (ret < 0) + return ret; + + ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL, + NULL, NULL); + fscache_end_operation(&cres); + return ret; } /* - * Retrieve a set of pages from FS-Cache + * Fallback page writing interface. */ -int __cifs_readpages_from_fscache(struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) +static int fscache_fallback_write_page(struct inode *inode, struct page *page, + bool no_space_allocated_yet) { - cifs_dbg(FYI, "%s: (0x%p/%u/0x%p)\n", - __func__, CIFS_I(inode)->fscache, *nr_pages, inode); - return -ENOBUFS; // Needs conversion to using netfslib + struct netfs_cache_resources cres; + struct fscache_cookie *cookie = cifs_inode_cookie(inode); + struct iov_iter iter; + struct bio_vec bvec[1]; + loff_t start = page_offset(page); + size_t len = PAGE_SIZE; + int ret; + + memset(&cres, 0, sizeof(cres)); + bvec[0].bv_page = page; + bvec[0].bv_offset = 0; + bvec[0].bv_len = PAGE_SIZE; + iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE); + + ret = fscache_begin_write_operation(&cres, cookie); + if (ret < 0) + return ret; + + ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode), + no_space_allocated_yet); + if (ret == 0) + ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL); + fscache_end_operation(&cres); + return ret; } -void __cifs_readpage_to_fscache(struct inode *inode, struct page *page) +/* + * Retrieve a page from FS-Cache + */ +int __cifs_readpage_from_fscache(struct inode *inode, struct page *page) { - struct cifsInodeInfo *cifsi = CIFS_I(inode); + int ret; - WARN_ON(!cifsi->fscache); + cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n", + __func__, cifs_inode_cookie(inode), page, inode); + ret = fscache_fallback_read_page(inode, page); + if (ret < 0) + return ret; + + /* Read completed synchronously */ + SetPageUptodate(page); + return 0; +} + +void __cifs_readpage_to_fscache(struct inode *inode, struct page *page) +{ cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n", - __func__, cifsi->fscache, page, inode); + __func__, cifs_inode_cookie(inode), page, inode); + + fscache_fallback_write_page(inode, page, true); +} + +/* + * Query the cache occupancy. + */ +int __cifs_fscache_query_occupancy(struct inode *inode, + pgoff_t first, unsigned nr_pages, + pgoff_t *_data_first, + unsigned int *_data_nr_pages) +{ + struct netfs_cache_resources cres; + struct fscache_cookie *cookie = cifs_inode_cookie(inode); + loff_t start, data_start; + size_t len, data_len; + int ret; - // Needs conversion to using netfslib + ret = fscache_begin_read_operation(&cres, cookie); + if (ret < 0) + return ret; + + start = first * PAGE_SIZE; + len = nr_pages * PAGE_SIZE; + ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE, + &data_start, &data_len); + if (ret == 0) { + *_data_first = data_start / PAGE_SIZE; + *_data_nr_pages = len / PAGE_SIZE; + } + + fscache_end_operation(&cres); + return ret; } diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h index c6ca49ac33d4..ed4b08df1961 100644 --- a/fs/cifs/fscache.h +++ b/fs/cifs/fscache.h @@ -9,6 +9,7 @@ #ifndef _CIFS_FSCACHE_H #define _CIFS_FSCACHE_H +#include #include #include "cifsglob.h" @@ -58,14 +59,6 @@ void cifs_fscache_fill_coherency(struct inode *inode, } -extern int cifs_fscache_release_page(struct page *page, gfp_t gfp); -extern int __cifs_readpage_from_fscache(struct inode *, struct page *); -extern int __cifs_readpages_from_fscache(struct inode *, - struct address_space *, - struct list_head *, - unsigned *); -extern void __cifs_readpage_to_fscache(struct inode *, struct page *); - static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return CIFS_I(inode)->fscache; @@ -80,33 +73,52 @@ static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags i_size_read(inode), flags); } -static inline int cifs_readpage_from_fscache(struct inode *inode, - struct page *page) -{ - if (CIFS_I(inode)->fscache) - return __cifs_readpage_from_fscache(inode, page); +extern int __cifs_fscache_query_occupancy(struct inode *inode, + pgoff_t first, unsigned nr_pages, + pgoff_t *_data_first, + unsigned int *_data_nr_pages); - return -ENOBUFS; +static inline int cifs_fscache_query_occupancy(struct inode *inode, + pgoff_t first, unsigned nr_pages, + pgoff_t *_data_first, + unsigned int *_data_nr_pages) +{ + if (!cifs_inode_cookie(inode)) + return -ENOBUFS; + return __cifs_fscache_query_occupancy(inode, first, nr_pages, + _data_first, _data_nr_pages); } -static inline int cifs_readpages_from_fscache(struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) +extern int __cifs_readpage_from_fscache(struct inode *, struct page *); +extern void __cifs_readpage_to_fscache(struct inode *, struct page *); + + +static inline int cifs_readpage_from_fscache(struct inode *inode, + struct page *page) { - if (CIFS_I(inode)->fscache) - return __cifs_readpages_from_fscache(inode, mapping, pages, - nr_pages); + if (cifs_inode_cookie(inode)) + return __cifs_readpage_from_fscache(inode, page); return -ENOBUFS; } static inline void cifs_readpage_to_fscache(struct inode *inode, struct page *page) { - if (PageFsCache(page)) + if (cifs_inode_cookie(inode)) __cifs_readpage_to_fscache(inode, page); } +static inline int cifs_fscache_release_page(struct page *page, gfp_t gfp) +{ + if (PageFsCache(page)) { + if (current_is_kswapd() || !(gfp & __GFP_FS)) + return false; + wait_on_page_fscache(page); + fscache_note_page_release(cifs_inode_cookie(page->mapping->host)); + } + return true; +} + #else /* CONFIG_CIFS_FSCACHE */ static inline void cifs_fscache_fill_coherency(struct inode *inode, @@ -123,22 +135,29 @@ static inline void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool upd static inline struct fscache_cookie *cifs_inode_cookie(struct inode *inode) { return NULL; } static inline void cifs_invalidate_cache(struct inode *inode, unsigned int flags) {} -static inline int -cifs_readpage_from_fscache(struct inode *inode, struct page *page) +static inline int cifs_fscache_query_occupancy(struct inode *inode, + pgoff_t first, unsigned nr_pages, + pgoff_t *_data_first, + unsigned int *_data_nr_pages) { + *_data_first = ULONG_MAX; + *_data_nr_pages = 0; return -ENOBUFS; } -static inline int cifs_readpages_from_fscache(struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) +static inline int +cifs_readpage_from_fscache(struct inode *inode, struct page *page) { return -ENOBUFS; } -static inline void cifs_readpage_to_fscache(struct inode *inode, - struct page *page) {} +static inline +void cifs_readpage_to_fscache(struct inode *inode, struct page *page) {} + +static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) +{ + return true; /* May release page */ +} #endif /* CONFIG_CIFS_FSCACHE */