From patchwork Thu Jul 15 03:36:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12378733 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A515EC07E96 for ; Thu, 15 Jul 2021 04:41:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4EEC361360 for ; Thu, 15 Jul 2021 04:41:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4EEC361360 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A40CD8D0054; Thu, 15 Jul 2021 00:41:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A175F8D004B; Thu, 15 Jul 2021 00:41:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E0408D0054; Thu, 15 Jul 2021 00:41:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0205.hostedemail.com [216.40.44.205]) by kanga.kvack.org (Postfix) with ESMTP id 6B4468D004B for ; Thu, 15 Jul 2021 00:41:12 -0400 (EDT) Received: from smtpin38.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 583BE824556B for ; Thu, 15 Jul 2021 04:41:11 +0000 (UTC) X-FDA: 78363572742.38.9739EE0 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf04.hostedemail.com (Postfix) with ESMTP id BDCD350000A6 for ; Thu, 15 Jul 2021 04:41:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Y5UinLMttKqw/QQSFxAT646FpHEwMgiRMjMa0npizhw=; b=WFH6dlsELQVVjX+HV0NFGHdH0w eGSPPKkomxBY/it3OaWwIJtUH3cn/z61yOH2qmOC9bnKnvtnrdYsI7VaucKXIf0iN3o/fLuMXQqWN cXmR7nM2/96m5Ef5p1XljULiwp/SvpQpri892bhQWR8ThSYAz7lsfXONLYqW5wXFkuR69bXPRAMfl 2P3W7FLuQqA/pGWPvMQFTniqu9us+wmqZ0MMdu6hUTjcgzyl6k9Lrb7aU/AlJqNNf1a2RHSm995yd wDUtr9Z8BDkH1rsj1Vd0WdH6ECkWYO+ncm3Qj2MwyWhMwK7BLzFi2GeMsXg2MqnC6n0qVdhGFFuWK G0fBBm4w==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m3t9v-002yBw-SA; Thu, 15 Jul 2021 04:40:05 +0000 From: "Matthew Wilcox (Oracle)" To: linux-kernel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v14 078/138] mm/filemap: Add folio_mkwrite_check_truncate() Date: Thu, 15 Jul 2021 04:36:04 +0100 Message-Id: <20210715033704.692967-79-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210715033704.692967-1-willy@infradead.org> References: <20210715033704.692967-1-willy@infradead.org> MIME-Version: 1.0 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=WFH6dlsE; spf=none (imf04.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam02 X-Stat-Signature: uzd1a948oemxd4qxyzipnyc96dn7794o X-Rspamd-Queue-Id: BDCD350000A6 X-HE-Tag: 1626324070-797605 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This is the folio equivalent of page_mkwrite_check_truncate(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: David Howells --- include/linux/pagemap.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 412db88b8d0c..18c06c3e42c3 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -1121,6 +1121,34 @@ static inline unsigned long dir_pages(struct inode *inode) PAGE_SHIFT; } +/** + * folio_mkwrite_check_truncate - check if folio was truncated + * @folio: the folio to check + * @inode: the inode to check the folio against + * + * Return: the number of bytes in the folio up to EOF, + * or -EFAULT if the folio was truncated. + */ +static inline ssize_t folio_mkwrite_check_truncate(struct folio *folio, + struct inode *inode) +{ + loff_t size = i_size_read(inode); + pgoff_t index = size >> PAGE_SHIFT; + size_t offset = offset_in_folio(folio, size); + + if (!folio->mapping) + return -EFAULT; + + /* folio is wholly inside EOF */ + if (folio_next_index(folio) - 1 < index) + return folio_size(folio); + /* folio is wholly past EOF */ + if (folio->index > index || !offset) + return -EFAULT; + /* folio is partially inside EOF */ + return offset; +} + /** * page_mkwrite_check_truncate - check if page was truncated * @page: the page to check