From patchwork Thu Jan 27 16:02:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12726975 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 9DC14C433F5 for ; Thu, 27 Jan 2022 16:02:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243363AbiA0QCs (ORCPT ); Thu, 27 Jan 2022 11:02:48 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46539 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243384AbiA0QCo (ORCPT ); Thu, 27 Jan 2022 11:02:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643299363; 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=grgUgfVgMs24xTDdp7Xwmf4GZ7AO1AtKBw4OccoD5vE=; b=bbW45I/MxPuCCqFbORPsRapqGFL8n3EI3H1YmFbeQh9Jo5/qeXSTsROardlRHopkZQr7fQ KPYr+8yCX6P6VqhZ005orpgUF3aA2XA6Fk8uNxkzdqppXo6KXVmCkzXOaGS9sCCzCglrq4 6QrCfVhbX+HJrdoyLvfuUI2HwjJGBew= 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-110-HRdacyVINwuZeJox0qoJfA-1; Thu, 27 Jan 2022 11:02:38 -0500 X-MC-Unique: HRdacyVINwuZeJox0qoJfA-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 02F8C86A8A3; Thu, 27 Jan 2022 16:02:37 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id EBCDB22DEB; Thu, 27 Jan 2022 16:02:34 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 1/4] Fix a warning about a malformed kernel doc comment in cifs by removing the From: David Howells To: Steve French Cc: 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 16:02:34 +0000 Message-ID: <164329935406.843658.13491453034739838581.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 marker. Signed-off-by: David Howells --- fs/cifs/connect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 11a22a30ee14..ed210d774a21 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -162,7 +162,7 @@ static void cifs_resolve_server(struct work_struct *work) mutex_unlock(&server->srv_mutex); } -/** +/* * Mark all sessions and tcons for reconnect. * * @server needs to be previously set to CifsNeedReconnect. From patchwork Thu Jan 27 16:02:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12726976 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 1A601C433F5 for ; Thu, 27 Jan 2022 16:02:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243398AbiA0QCy (ORCPT ); Thu, 27 Jan 2022 11:02:54 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:49199 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243394AbiA0QCx (ORCPT ); Thu, 27 Jan 2022 11:02:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643299372; 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=R7H8HnWg6mvv+5wkCfISgYNI0aJyRykR/uY+lYkt+JU=; b=eHLLDDXJl2yXUWm4l+bNgSo148KJv8e0+8ZufZswaLpNaWlpLXRujErvvtaVJaQEwHY77Y i++Ypx5BWH3+Rn39wOcDWAB78L9d0/mzNyK2wLqGK5yQo9Xs5zkP1RSAmwgmh46t8RlsgY FE5NbBN4pg1C1nzKC6AsPoyt+JsGQY8= 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-211-yYxnuKQ1PVWYC0je-bub3A-1; Thu, 27 Jan 2022 11:02:46 -0500 X-MC-Unique: yYxnuKQ1PVWYC0je-bub3A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 12D382FD1B; Thu, 27 Jan 2022 16:02:45 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 172E51091ED5; Thu, 27 Jan 2022 16:02:42 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 2/4] cifs: Transition from ->readpages() to ->readahead() From: David Howells To: Steve French Cc: Shyam Prasad N , Matthew Wilcox , Jeff Layton , 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 16:02:42 +0000 Message-ID: <164329936223.843658.12642597353101325076.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 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Transition the cifs filesystem from using the old ->readpages() method to using the new ->readahead() method. For the moment, this removes any invocation of fscache to read data from the local cache, leaving that to another patch. Signed-off-by: David Howells cc: Steve French cc: Shyam Prasad N cc: Matthew Wilcox cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: linux-cachefs@redhat.com --- fs/cifs/file.c | 172 +++++++++++--------------------------------------------- 1 file changed, 35 insertions(+), 137 deletions(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 59334be9ed3b..be62dc29dc54 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -4269,8 +4269,6 @@ cifs_readv_complete(struct work_struct *work) for (i = 0; i < rdata->nr_pages; i++) { struct page *page = rdata->pages[i]; - lru_cache_add(page); - if (rdata->result == 0 || (rdata->result == -EAGAIN && got_bytes)) { flush_dcache_page(page); @@ -4340,7 +4338,6 @@ readpages_fill_pages(struct TCP_Server_Info *server, * fill them until the writes are flushed. */ zero_user(page, 0, PAGE_SIZE); - lru_cache_add(page); flush_dcache_page(page); SetPageUptodate(page); unlock_page(page); @@ -4350,7 +4347,6 @@ readpages_fill_pages(struct TCP_Server_Info *server, continue; } else { /* no need to hold page hostage */ - lru_cache_add(page); unlock_page(page); put_page(page); rdata->pages[i] = NULL; @@ -4393,92 +4389,16 @@ cifs_readpages_copy_into_pages(struct TCP_Server_Info *server, return readpages_fill_pages(server, rdata, iter, iter->count); } -static int -readpages_get_pages(struct address_space *mapping, struct list_head *page_list, - unsigned int rsize, struct list_head *tmplist, - unsigned int *nr_pages, loff_t *offset, unsigned int *bytes) +static void cifs_readahead(struct readahead_control *ractl) { - struct page *page, *tpage; - unsigned int expected_index; int rc; - gfp_t gfp = readahead_gfp_mask(mapping); - - INIT_LIST_HEAD(tmplist); - - page = lru_to_page(page_list); - - /* - * Lock the page and put it in the cache. Since no one else - * should have access to this page, we're safe to simply set - * PG_locked without checking it first. - */ - __SetPageLocked(page); - rc = add_to_page_cache_locked(page, mapping, - page->index, gfp); - - /* give up if we can't stick it in the cache */ - if (rc) { - __ClearPageLocked(page); - return rc; - } - - /* move first page to the tmplist */ - *offset = (loff_t)page->index << PAGE_SHIFT; - *bytes = PAGE_SIZE; - *nr_pages = 1; - list_move_tail(&page->lru, tmplist); - - /* now try and add more pages onto the request */ - expected_index = page->index + 1; - list_for_each_entry_safe_reverse(page, tpage, page_list, lru) { - /* discontinuity ? */ - if (page->index != expected_index) - break; - - /* would this page push the read over the rsize? */ - if (*bytes + PAGE_SIZE > rsize) - break; - - __SetPageLocked(page); - rc = add_to_page_cache_locked(page, mapping, page->index, gfp); - if (rc) { - __ClearPageLocked(page); - break; - } - list_move_tail(&page->lru, tmplist); - (*bytes) += PAGE_SIZE; - expected_index++; - (*nr_pages)++; - } - return rc; -} - -static int cifs_readpages(struct file *file, struct address_space *mapping, - struct list_head *page_list, unsigned num_pages) -{ - int rc; - int err = 0; - struct list_head tmplist; - struct cifsFileInfo *open_file = file->private_data; - struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file); + struct cifsFileInfo *open_file = ractl->file->private_data; + struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(ractl->file); struct TCP_Server_Info *server; pid_t pid; - unsigned int xid; + unsigned int xid, last_batch_size = 0; xid = get_xid(); - /* - * Reads as many pages as possible from fscache. Returns -ENOBUFS - * immediately if the cookie is negative - * - * After this point, every page in the list might have PG_fscache set, - * so we will need to clean that up off of every page we don't use. - */ - rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list, - &num_pages); - if (rc == 0) { - free_xid(xid); - return rc; - } if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) pid = open_file->pid; @@ -4489,39 +4409,32 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses); cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n", - __func__, file, mapping, num_pages); + __func__, ractl->file, ractl->mapping, readahead_count(ractl)); /* - * Start with the page at end of list and move it to private - * list. Do the same with any following pages until we hit - * the rsize limit, hit an index discontinuity, or run out of - * pages. Issue the async read and then start the loop again - * until the list is empty. - * - * Note that list order is important. The page_list is in - * the order of declining indexes. When we put the pages in - * the rdata->pages, then we want them in increasing order. + * Chop the readahead request up into rsize-sized read requests. */ - while (!list_empty(page_list) && !err) { - unsigned int i, nr_pages, bytes, rsize; - loff_t offset; - struct page *page, *tpage; + while (readahead_count(ractl) - last_batch_size) { + unsigned int i, nr_pages, got, rsize; + struct page *page; struct cifs_readdata *rdata; struct cifs_credits credits_on_stack; struct cifs_credits *credits = &credits_on_stack; if (open_file->invalidHandle) { rc = cifs_reopen_file(open_file, true); - if (rc == -EAGAIN) - continue; - else if (rc) + if (rc) { + if (rc == -EAGAIN) + continue; break; + } } rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize, &rsize, credits); if (rc) break; + nr_pages = min_t(size_t, rsize / PAGE_SIZE, readahead_count(ractl)); /* * Give up immediately if rsize is too small to read an entire @@ -4529,16 +4442,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, * reach this point however since we set ra_pages to 0 when the * rsize is smaller than a cache page. */ - if (unlikely(rsize < PAGE_SIZE)) { - add_credits_and_wake_if(server, credits, 0); - free_xid(xid); - return 0; - } - - nr_pages = 0; - err = readpages_get_pages(mapping, page_list, rsize, &tmplist, - &nr_pages, &offset, &bytes); - if (!nr_pages) { + if (unlikely(!nr_pages)) { add_credits_and_wake_if(server, credits, 0); break; } @@ -4546,36 +4450,31 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete); if (!rdata) { /* best to give up if we're out of mem */ - list_for_each_entry_safe(page, tpage, &tmplist, lru) { - list_del(&page->lru); - lru_cache_add(page); - unlock_page(page); - put_page(page); - } - rc = -ENOMEM; add_credits_and_wake_if(server, credits, 0); break; } - rdata->cfile = cifsFileInfo_get(open_file); - rdata->server = server; - rdata->mapping = mapping; - rdata->offset = offset; - rdata->bytes = bytes; - rdata->pid = pid; - rdata->pagesz = PAGE_SIZE; - rdata->tailsz = PAGE_SIZE; + got = __readahead_batch(ractl, rdata->pages, nr_pages); + if (got != nr_pages) { + pr_warn("__readahead_batch() returned %u/%u\n", + got, nr_pages); + nr_pages = got; + } + + rdata->nr_pages = nr_pages; + rdata->bytes = readahead_batch_length(ractl); + rdata->cfile = cifsFileInfo_get(open_file); + rdata->server = server; + rdata->mapping = ractl->mapping; + rdata->offset = readahead_pos(ractl); + rdata->pid = pid; + rdata->pagesz = PAGE_SIZE; + rdata->tailsz = PAGE_SIZE; rdata->read_into_pages = cifs_readpages_read_into_pages; rdata->copy_into_pages = cifs_readpages_copy_into_pages; - rdata->credits = credits_on_stack; - - list_for_each_entry_safe(page, tpage, &tmplist, lru) { - list_del(&page->lru); - rdata->pages[rdata->nr_pages++] = page; - } + rdata->credits = credits_on_stack; rc = adjust_credits(server, &rdata->credits, rdata->bytes); - if (!rc) { if (rdata->cfile->invalidHandle) rc = -EAGAIN; @@ -4587,7 +4486,6 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, add_credits_and_wake_if(server, &rdata->credits, 0); for (i = 0; i < rdata->nr_pages; i++) { page = rdata->pages[i]; - lru_cache_add(page); unlock_page(page); put_page(page); } @@ -4597,10 +4495,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, } kref_put(&rdata->refcount, cifs_readdata_release); + last_batch_size = nr_pages; } free_xid(xid); - return rc; } /* @@ -4924,7 +4822,7 @@ void cifs_oplock_break(struct work_struct *work) * In the non-cached mode (mount with cache=none), we shunt off direct read and write requests * so this method should never be called. * - * Direct IO is not yet supported in the cached mode. + * Direct IO is not yet supported in the cached mode. */ static ssize_t cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter) @@ -5006,7 +4904,7 @@ static int cifs_set_page_dirty(struct page *page) const struct address_space_operations cifs_addr_ops = { .readpage = cifs_readpage, - .readpages = cifs_readpages, + .readahead = cifs_readahead, .writepage = cifs_writepage, .writepages = cifs_writepages, .write_begin = cifs_write_begin, From patchwork Thu Jan 27 16:02:50 2022 Content-Type: text/plain; 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 3/4] netfs, cachefiles: Add a method to query presence of data in the cache From: David Howells To: Steve French Cc: 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 16:02:50 +0000 Message-ID: <164329937029.843658.11237280189554156735.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 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Add a netfs_cache_ops method by which a network filesystem can ask the cache about what data it has available and where so that it can make a multipage read more efficient. Signed-off-by: David Howells cc: linux-cachefs@redhat.com --- Documentation/filesystems/netfs_library.rst | 16 +++++++ fs/cachefiles/io.c | 59 +++++++++++++++++++++++++++ include/linux/netfs.h | 7 +++ 3 files changed, 82 insertions(+) diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst index 136f8da3d0e2..4f373a8ec47b 100644 --- a/Documentation/filesystems/netfs_library.rst +++ b/Documentation/filesystems/netfs_library.rst @@ -462,6 +462,10 @@ operation table looks like the following:: struct iov_iter *iter, netfs_io_terminated_t term_func, void *term_func_priv); + + int (*query_occupancy)(struct netfs_cache_resources *cres, + loff_t start, size_t len, size_t granularity, + loff_t *_data_start, size_t *_data_len); }; With a termination handler function pointer:: @@ -536,6 +540,18 @@ The methods defined in the table are: indicating whether the termination is definitely happening in the caller's context. + * ``query_occupancy()`` + + [Required] Called to find out where the next piece of data is within a + particular region of the cache. The start and length of the region to be + queried are passed in, along with the granularity to which the answer needs + to be aligned. The function passes back the start and length of the data, + if any, available within that region. Note that there may be a hole at the + front. + + It returns 0 if some data was found, -ENODATA if there was no usable data + within the region or -ENOBUFS if there is no caching on this file. + Note that these methods are passed a pointer to the cache resource structure, not the read request structure as they could be used in other situations where there isn't a read request structure as well, such as writing dirty data to the diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c index 04eb52736990..753986ea1583 100644 --- a/fs/cachefiles/io.c +++ b/fs/cachefiles/io.c @@ -191,6 +191,64 @@ static int cachefiles_read(struct netfs_cache_resources *cres, return ret; } +/* + * Query the occupancy of the cache in a region, returning where the next chunk + * of data starts and how long it is. + */ +static int cachefiles_query_occupancy(struct netfs_cache_resources *cres, + loff_t start, size_t len, size_t granularity, + loff_t *_data_start, size_t *_data_len) +{ + struct cachefiles_object *object; + struct file *file; + loff_t off, off2; + + *_data_start = -1; + *_data_len = 0; + + if (!fscache_wait_for_operation(cres, FSCACHE_WANT_READ)) + return -ENOBUFS; + + object = cachefiles_cres_object(cres); + file = cachefiles_cres_file(cres); + granularity = max_t(size_t, object->volume->cache->bsize, granularity); + + _enter("%pD,%li,%llx,%zx/%llx", + file, file_inode(file)->i_ino, start, len, + i_size_read(file_inode(file))); + + off = cachefiles_inject_read_error(); + if (off == 0) + off = vfs_llseek(file, start, SEEK_DATA); + if (off == -ENXIO) + return -ENODATA; /* Beyond EOF */ + if (off < 0 && off >= (loff_t)-MAX_ERRNO) + return -ENOBUFS; /* Error. */ + if (round_up(off, granularity) >= start + len) + return -ENODATA; /* No data in range */ + + off2 = cachefiles_inject_read_error(); + if (off2 == 0) + off2 = vfs_llseek(file, off, SEEK_HOLE); + if (off2 == -ENXIO) + return -ENODATA; /* Beyond EOF */ + if (off2 < 0 && off2 >= (loff_t)-MAX_ERRNO) + return -ENOBUFS; /* Error. */ + + /* Round away partial blocks */ + off = round_up(off, granularity); + off2 = round_down(off2, granularity); + if (off2 <= off) + return -ENODATA; + + *_data_start = off; + if (off2 > start + len) + *_data_len = len; + else + *_data_len = off2 - off; + return 0; +} + /* * Handle completion of a write to the cache. */ @@ -545,6 +603,7 @@ static const struct netfs_cache_ops cachefiles_netfs_cache_ops = { .write = cachefiles_write, .prepare_read = cachefiles_prepare_read, .prepare_write = cachefiles_prepare_write, + .query_occupancy = cachefiles_query_occupancy, }; /* diff --git a/include/linux/netfs.h b/include/linux/netfs.h index b46c39d98bbd..614f22213e21 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -244,6 +244,13 @@ struct netfs_cache_ops { int (*prepare_write)(struct netfs_cache_resources *cres, loff_t *_start, size_t *_len, loff_t i_size, bool no_space_allocated_yet); + + /* Query the occupancy of the cache in a region, returning where the + * next chunk of data starts and how long it is. + */ + int (*query_occupancy)(struct netfs_cache_resources *cres, + loff_t start, size_t len, size_t granularity, + loff_t *_data_start, size_t *_data_len); }; struct readahead_control; 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; 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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 */