From patchwork Tue Jan 3 10:44:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 13087361 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 19BA3C46467 for ; Tue, 3 Jan 2023 10:45:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237216AbjACKpB (ORCPT ); Tue, 3 Jan 2023 05:45:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237128AbjACKoi (ORCPT ); Tue, 3 Jan 2023 05:44:38 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BFC729592 for ; Tue, 3 Jan 2023 02:44:37 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 7C8283855F; Tue, 3 Jan 2023 10:44:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1672742676; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6PZfa14X74RoBzPDavN3w+TqisCcRb26GNpQu8tmi2Q=; b=gCXyyFYkEoq1GsRkAjsn3sDVIoAvtNvtmfZTofBUyUF1K0eoNhGKz2Nj/zi49dwo6kZDRx mfQAwfonX77SW/a7XryJ56GkXb2mmLDxbi3koVYCCI5Ok+jKD3UMXhyPJVJhoBM/R7Cr4L tOxsdJSNoW4R6HutJE3GHXNsGEAAkoQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1672742676; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6PZfa14X74RoBzPDavN3w+TqisCcRb26GNpQu8tmi2Q=; b=TYCs55YaqD0hcrSch8xT2NtH4DSsUbF/pEH8Nu7nm1CSXTsaM1GIo8bTaCHLj/Bte2tfV4 fQrbhMx9TTMQeiBQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 6DED91390C; Tue, 3 Jan 2023 10:44:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id Z4rRGhQHtGMdTAAAMHmgww (envelope-from ); Tue, 03 Jan 2023 10:44:36 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id EC38CA0742; Tue, 3 Jan 2023 11:44:35 +0100 (CET) From: Jan Kara To: Cc: Matthew Wilcox , Christoph Hellwig , Andrew Morton , Jan Kara Subject: [PATCH] fs: don't allocate blocks beyond EOF from __mpage_writepage Date: Tue, 3 Jan 2023 11:44:30 +0100 Message-Id: <20230103104430.27749-1-jack@suse.cz> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1034; i=jack@suse.cz; h=from:subject; bh=v/6sM6EENHzqzWQReoWn9B5pKtwhLRZbJueMePY1O1I=; b=owEBbQGS/pANAwAIAZydqgc/ZEDZAcsmYgBjtAcN8ap40RQH5vExQOW0af6TRCqMWSOJQ3XEcP2g XmJw7uWJATMEAAEIAB0WIQSrWdEr1p4yirVVKBycnaoHP2RA2QUCY7QHDQAKCRCcnaoHP2RA2dFLCA DIuUQDyK5U3UFStsY5eCo06MH22cqChk7P/rZ4B/rMLKfnWgpBJS7WwNt6rlm/tx4q2mKWQUs0PWCG p4+5uun7k2aPrWBxbAHpzYf+7IUvd+0SIHKTYMw/YDdxzJbxwd7V0y+b/hm0u/Y4w8G99meMQbTbhm FkYagCCLbqYCO6IlLj+87MQwkjRr2LnMQafgxLS1bbjJdHWdEa2Wu0XRhaRKkw0cwoj7cx0r9IaADt zuJWy38uobNp5WuY7oXt0I+Q0G08jYPC9ELuAVDtx9QuZj1AvLD+xxDz2LfMXUDk2o+EIMGSAki6ce hRp247m+bqTuGOGJ0FU3zzpKCuAKYv X-Developer-Key: i=jack@suse.cz; a=openpgp; fpr=93C6099A142276A28BBE35D815BC833443038D8C Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When __mpage_writepage() is called for a page beyond EOF, it will go and allocate all blocks underlying the page. This is not only unnecessary but this way blocks can get leaked (e.g. if a page beyond EOF is marked dirty but in the end write fails and i_size is not extended). Signed-off-by: Jan Kara Reviewed-by: Christoph Hellwig --- fs/mpage.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/mpage.c b/fs/mpage.c index 0f8ae954a579..9f040c1d5912 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -524,6 +524,12 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc, */ BUG_ON(!PageUptodate(page)); block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits); + /* + * Whole page beyond EOF? Skip allocating blocks to avoid leaking + * space. + */ + if (block_in_file >= (i_size + (1 << blkbits) - 1) >> blkbits) + goto page_is_mapped; last_block = (i_size - 1) >> blkbits; map_bh.b_page = page; for (page_block = 0; page_block < blocks_per_page; ) {