From patchwork Thu Jul 15 20:00:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthew Wilcox (Oracle)" X-Patchwork-Id: 12381055 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 18EA5C636C9 for ; Thu, 15 Jul 2021 20:31:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BB1FA613D4 for ; Thu, 15 Jul 2021 20:31:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB1FA613D4 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 24E018D00FD; Thu, 15 Jul 2021 16:31:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1FE458D00EC; Thu, 15 Jul 2021 16:31:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0C6738D00FD; Thu, 15 Jul 2021 16:31:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0037.hostedemail.com [216.40.44.37]) by kanga.kvack.org (Postfix) with ESMTP id DDD348D00EC for ; Thu, 15 Jul 2021 16:31:15 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C0D94BBDB for ; Thu, 15 Jul 2021 20:31:14 +0000 (UTC) X-FDA: 78365966868.17.67E6DDD Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 89E553000103 for ; Thu, 15 Jul 2021 20:31:14 +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=LY08HvZb1KdMfnKkEHmmRuOxfO GrLaQK7gJoqeX6SGaDFpYBnkIgBgeDrMTufPukFJbdIz8YhGKMuMdLLzvvWqLg55dJFet11wvGZ63 2JFOZjBn2a0XoRsdkNQ0tt7tCU32oYPSbHanmrMygve57dTD1KC8SYOXO11zztGf6bpmnibyB2Vg1 LzIFcxCM6etRinsZEh8NIwf0oAZjEuKgwubFSOrje0DoGblLXapjYw+Vz0JvQaZ1R6nkPfaCSSTmw 9jl1jLgyb43cmgHFTKvWmhAFKjP2g/lOdXRoLG28pVAvfGNpks1HANlBG8wBBM6sOpg8k6WpDWVDK P1vIVVKQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m47yq-003pwV-Ht; Thu, 15 Jul 2021 20:29:31 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" Subject: [PATCH v14 28/39] mm/filemap: Add folio_mkwrite_check_truncate() Date: Thu, 15 Jul 2021 21:00:19 +0100 Message-Id: <20210715200030.899216-29-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210715200030.899216-1-willy@infradead.org> References: <20210715200030.899216-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 89E553000103 X-Stat-Signature: mtodufhbgiagjtmum8ociwj7kx1hrzbw Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=LY08HvZb; spf=none (imf09.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-HE-Tag: 1626381074-874654 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) --- 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