From patchwork Thu Oct 29 13:23:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brian Foster X-Patchwork-Id: 11866373 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0882D139F for ; Thu, 29 Oct 2020 13:24:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6E672076E for ; Thu, 29 Oct 2020 13:24:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VS4DRljD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727052AbgJ2NYI (ORCPT ); Thu, 29 Oct 2020 09:24:08 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:48066 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727005AbgJ2NYH (ORCPT ); Thu, 29 Oct 2020 09:24:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603977845; 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=OY8uEFwhhCpbmM11k5zwiPPtYztte7utm2kD/PT+in0=; b=VS4DRljDQW9N4vzYofxoyU5XPq04PG5PrrPRJ/bx/YYUdzHzsJ8Cmea8I92kD0kxQOr0PS XR5hchJMEtYwBSfUueuXiVh7Yaw8xQRqJOvngdL1jbsP/El/4LGRd/mlUQ8bRB9u6WO2pb Md9KOm/ZXtXk0cW3E0goVYot1V1gn20= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-259-8bXqWVDLPUO2LkwtrbwbvA-1; Thu, 29 Oct 2020 09:24:03 -0400 X-MC-Unique: 8bXqWVDLPUO2LkwtrbwbvA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1162B195D435; Thu, 29 Oct 2020 13:23:28 +0000 (UTC) Received: from bfoster.redhat.com (ovpn-113-186.rdu2.redhat.com [10.10.113.186]) by smtp.corp.redhat.com (Postfix) with ESMTP id 992245C63A; Thu, 29 Oct 2020 13:23:27 +0000 (UTC) From: Brian Foster To: linux-fsdevel@vger.kernel.org Cc: linux-xfs@vger.kernel.org Subject: [PATCH v2 2/3] iomap: support partial page discard on writeback block mapping failure Date: Thu, 29 Oct 2020 09:23:24 -0400 Message-Id: <20201029132325.1663790-3-bfoster@redhat.com> In-Reply-To: <20201029132325.1663790-1-bfoster@redhat.com> References: <20201029132325.1663790-1-bfoster@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org iomap writeback mapping failure only calls into ->discard_page() if the current page has not been added to the ioend. Accordingly, the XFS callback assumes a full page discard and invalidation. This is problematic for sub-page block size filesystems where some portion of a page might have been mapped successfully before a failure to map a delalloc block occurs. ->discard_page() is not called in that error scenario and the bio is explicitly failed by iomap via the error return from ->prepare_ioend(). As a result, the filesystem leaks delalloc blocks and corrupts the filesystem block counters. Since XFS is the only user of ->discard_page(), tweak the semantics to invoke the callback unconditionally on mapping errors and provide the file offset that failed to map. Update xfs_discard_page() to discard the corresponding portion of the file and pass the range along to iomap_invalidatepage(). The latter already properly handles both full and sub-page scenarios by not changing any iomap or page state on sub-page invalidations. Signed-off-by: Brian Foster Reviewed-by: Christoph Hellwig --- fs/iomap/buffered-io.c | 15 ++++++++------- fs/xfs/xfs_aops.c | 13 +++++++------ include/linux/iomap.h | 2 +- 3 files changed, 16 insertions(+), 14 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index bcfc288dba3f..d1f04eabc7e4 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1412,14 +1412,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, * appropriately. */ if (unlikely(error)) { + /* + * Let the filesystem know what portion of the current page + * failed to map. If the page wasn't been added to ioend, it + * won't be affected by I/O completion and we must unlock it + * now. + */ + if (wpc->ops->discard_page) + wpc->ops->discard_page(page, file_offset); if (!count) { - /* - * If the current page hasn't been added to ioend, it - * won't be affected by I/O completions and we must - * discard and unlock it right here. - */ - if (wpc->ops->discard_page) - wpc->ops->discard_page(page); ClearPageUptodate(page); unlock_page(page); goto done; diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index b35611882ff9..46920c530b20 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -527,13 +527,14 @@ xfs_prepare_ioend( */ static void xfs_discard_page( - struct page *page) + struct page *page, + loff_t fileoff) { struct inode *inode = page->mapping->host; struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; - loff_t offset = page_offset(page); - xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset); + unsigned int pageoff = offset_in_page(fileoff); + xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff); int error; if (XFS_FORCED_SHUTDOWN(mp)) @@ -541,14 +542,14 @@ xfs_discard_page( xfs_alert_ratelimited(mp, "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.", - page, ip->i_ino, offset); + page, ip->i_ino, fileoff); error = xfs_bmap_punch_delalloc_range(ip, start_fsb, - PAGE_SIZE / i_blocksize(inode)); + (PAGE_SIZE - pageoff) / i_blocksize(inode)); if (error && !XFS_FORCED_SHUTDOWN(mp)) xfs_alert(mp, "page discard unable to remove delalloc mapping."); out_invalidate: - iomap_invalidatepage(page, 0, PAGE_SIZE); + iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff); } static const struct iomap_writeback_ops xfs_writeback_ops = { diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 4d1d3c3469e9..36e0ab19210a 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -220,7 +220,7 @@ struct iomap_writeback_ops { * Optional, allows the file system to discard state on a page where * we failed to submit any I/O. */ - void (*discard_page)(struct page *page); + void (*discard_page)(struct page *page, loff_t fileoff); }; struct iomap_writepage_ctx {