From patchwork Sun Jan 8 19:40:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 13092666 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 8BFC3C54EBC for ; Sun, 8 Jan 2023 19:43:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234617AbjAHTnm (ORCPT ); Sun, 8 Jan 2023 14:43:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234231AbjAHTnH (ORCPT ); Sun, 8 Jan 2023 14:43:07 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7786DF24 for ; Sun, 8 Jan 2023 11:41:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673206866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WHGmm+6pyhfRGaoS1tmIeM5ClqKPuUJWD5zTFMeTau0=; b=MHYo8a0QMIad+hT8+/DFaOg28ZED93/VwR/Blj/9eK6CI5H0A7+cVNC+T7vUeV8TnI42tH irqYGDrNhZ45ILlF5IDwAkKVNNl9CtnIPPKNo3RJ95vpZ+zZklP9z3/t/jkEaBMK4H6uPc VG3BIjeX0zNQ3tDbX7MeT3DEWDioNzE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-518-KEJkthAlMJaUugpo3cwnOQ-1; Sun, 08 Jan 2023 14:41:01 -0500 X-MC-Unique: KEJkthAlMJaUugpo3cwnOQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3CF073806077; Sun, 8 Jan 2023 19:41:01 +0000 (UTC) Received: from pasta.redhat.com (ovpn-192-3.brq.redhat.com [10.40.192.3]) by smtp.corp.redhat.com (Postfix) with ESMTP id BC023492B06; Sun, 8 Jan 2023 19:40:58 +0000 (UTC) From: Andreas Gruenbacher To: Christoph Hellwig , "Darrick J . Wong" , Alexander Viro , Matthew Wilcox Cc: Andreas Gruenbacher , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, cluster-devel@redhat.com Subject: [RFC v6 08/10] iomap/xfs: Eliminate the iomap_valid handler Date: Sun, 8 Jan 2023 20:40:32 +0100 Message-Id: <20230108194034.1444764-9-agruenba@redhat.com> In-Reply-To: <20230108194034.1444764-1-agruenba@redhat.com> References: <20230108194034.1444764-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Eliminate the ->iomap_valid() handler by switching to a ->get_folio() handler and validating the mapping there. Signed-off-by: Andreas Gruenbacher Reviewed-by: Christoph Hellwig --- fs/iomap/buffered-io.c | 26 +++++--------------------- fs/xfs/xfs_iomap.c | 37 ++++++++++++++++++++++++++----------- include/linux/iomap.h | 23 ++++++----------------- 3 files changed, 37 insertions(+), 49 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 006ddf933948..72dfbc3cb086 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -638,10 +638,9 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter, static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, size_t len, struct folio **foliop) { - const struct iomap_page_ops *page_ops = iter->iomap.page_ops; const struct iomap *srcmap = iomap_iter_srcmap(iter); struct folio *folio; - int status = 0; + int status; BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length); if (srcmap != &iter->iomap) @@ -654,27 +653,12 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); folio = __iomap_get_folio(iter, pos, len); - if (IS_ERR(folio)) - return PTR_ERR(folio); - - /* - * Now we have a locked folio, before we do anything with it we need to - * check that the iomap we have cached is not stale. The inode extent - * mapping can change due to concurrent IO in flight (e.g. - * IOMAP_UNWRITTEN state can change and memory reclaim could have - * reclaimed a previously partially written page at this index after IO - * completion before this write reaches this file offset) and hence we - * could do the wrong thing here (zero a page range incorrectly or fail - * to zero) and corrupt data. - */ - if (page_ops && page_ops->iomap_valid) { - bool iomap_valid = page_ops->iomap_valid(iter->inode, - &iter->iomap); - if (!iomap_valid) { + if (IS_ERR(folio)) { + if (folio == ERR_PTR(-ESTALE)) { iter->iomap.flags |= IOMAP_F_STALE; - status = 0; - goto out_unlock; + return 0; } + return PTR_ERR(folio); } if (pos + len > folio_pos(folio) + folio_size(folio)) diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 669c1bc5c3a7..d0bf99539180 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -62,29 +62,44 @@ xfs_iomap_inode_sequence( return cookie | READ_ONCE(ip->i_df.if_seq); } -/* - * Check that the iomap passed to us is still valid for the given offset and - * length. - */ -static bool -xfs_iomap_valid( - struct inode *inode, - const struct iomap *iomap) +static struct folio * +xfs_get_folio( + struct iomap_iter *iter, + loff_t pos, + unsigned len) { + struct inode *inode = iter->inode; + struct iomap *iomap = &iter->iomap; struct xfs_inode *ip = XFS_I(inode); + struct folio *folio; + folio = iomap_get_folio(iter, pos); + if (IS_ERR(folio)) + return folio; + + /* + * Now that we have a locked folio, we need to check that the iomap we + * have cached is not stale. The inode extent mapping can change due to + * concurrent IO in flight (e.g., IOMAP_UNWRITTEN state can change and + * memory reclaim could have reclaimed a previously partially written + * page at this index after IO completion before this write reaches + * this file offset) and hence we could do the wrong thing here (zero a + * page range incorrectly or fail to zero) and corrupt data. + */ if (iomap->validity_cookie != xfs_iomap_inode_sequence(ip, iomap->flags)) { trace_xfs_iomap_invalid(ip, iomap); - return false; + folio_unlock(folio); + folio_put(folio); + return ERR_PTR(-ESTALE); } XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS); - return true; + return folio; } const struct iomap_page_ops xfs_iomap_page_ops = { - .iomap_valid = xfs_iomap_valid, + .get_folio = xfs_get_folio, }; int diff --git a/include/linux/iomap.h b/include/linux/iomap.h index da226032aedc..0ae2cddbedd6 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -134,29 +134,18 @@ static inline bool iomap_inline_data_valid(const struct iomap *iomap) * When get_folio succeeds, put_folio will always be called to do any * cleanup work necessary. put_folio is responsible for unlocking and putting * @folio. + * + * When an iomap is created, the filesystem can store internal state (e.g., a + * sequence number) in iomap->validity_cookie. The get_folio handler can use + * this validity cookie to detect when the iomap needs to be refreshed because + * it is no longer up to date. In that case, the function should return + * ERR_PTR(-ESTALE) to retry the operation with a fresh mapping. */ struct iomap_page_ops { struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos, unsigned len); void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied, struct folio *folio); - - /* - * Check that the cached iomap still maps correctly to the filesystem's - * internal extent map. FS internal extent maps can change while iomap - * is iterating a cached iomap, so this hook allows iomap to detect that - * the iomap needs to be refreshed during a long running write - * operation. - * - * The filesystem can store internal state (e.g. a sequence number) in - * iomap->validity_cookie when the iomap is first mapped to be able to - * detect changes between mapping time and whenever .iomap_valid() is - * called. - * - * This is called with the folio over the specified file position held - * locked by the iomap code. - */ - bool (*iomap_valid)(struct inode *inode, const struct iomap *iomap); }; /*