From mboxrd@z Thu Jan 1 00:00:00 1970 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 A0CDCC001B2 for ; Mon, 12 Dec 2022 02:16:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231277AbiLLCQc (ORCPT ); Sun, 11 Dec 2022 21:16:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231249AbiLLCOk (ORCPT ); Sun, 11 Dec 2022 21:14:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4A55116D for ; Sun, 11 Dec 2022 18:14:35 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 947A8B80B69 for ; Mon, 12 Dec 2022 02:14:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E272C433EF; Mon, 12 Dec 2022 02:14:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1670811273; bh=QtjNMMITobjn+cIAWuxhyZzT0QeWngD9zcvLPuXB5GE=; h=Date:To:From:Subject:From; b=uhdTqFfUmNZGX71H8J59W7pyE9ARFOJjqE0puOc12IxfUE0g6hdYAkmmxU/KiF0u+ 00BMvJvMi02juN9lNx1xDIf61BeDhFgPe2RNddAiC47ghDSJon3+X+qyMt12ZvuLol RlSY7rLylkvNFMkJjJcecYM0OSUNKfOQ5qyVs5V4= Date: Sun, 11 Dec 2022 18:14:32 -0800 To: mm-commits@vger.kernel.org, jhubbard@nvidia.com, jgg@nvidia.com, djwong@kernel.org, david@fromorbit.com, dan.j.williams@intel.com, apopple@nvidia.com, allison.henderson@oracle.com, ruansy.fnst@fujitsu.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] fsdax-zero-the-edges-if-source-is-hole-or-unwritten.patch removed from -mm tree Message-Id: <20221212021433.4E272C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: fsdax: zero the edges if source is HOLE or UNWRITTEN has been removed from the -mm tree. Its filename was fsdax-zero-the-edges-if-source-is-hole-or-unwritten.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Shiyang Ruan Subject: fsdax: zero the edges if source is HOLE or UNWRITTEN Date: Thu, 1 Dec 2022 15:28:53 +0000 If srcmap contains invalid data, such as HOLE and UNWRITTEN, the dest page should be zeroed. Otherwise, since it's a pmem, old data may remains on the dest page, the result of CoW will be incorrect. The function name is also not easy to understand, rename it to "dax_iomap_copy_around()", which means it copies data around the range. [akpm@linux-foundation.org: update dax_iomap_copy_around() kerneldoc, per Darrick] Link: https://lkml.kernel.org/r/1669973145-318-1-git-send-email-ruansy.fnst@fujitsu.com Link: https://lkml.kernel.org/r/1669908538-55-4-git-send-email-ruansy.fnst@fujitsu.com Signed-off-by: Shiyang Ruan Reviewed-by: Darrick J. Wong Reviewed-by: Allison Henderson Cc: Alistair Popple Cc: Dan Williams Cc: Dave Chinner Cc: Jason Gunthorpe Cc: John Hubbard Signed-off-by: Andrew Morton --- fs/dax.c | 79 ++++++++++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 30 deletions(-) --- a/fs/dax.c~fsdax-zero-the-edges-if-source-is-hole-or-unwritten +++ a/fs/dax.c @@ -1092,7 +1092,8 @@ out: } /** - * dax_iomap_cow_copy - Copy the data from source to destination before write + * dax_iomap_copy_around - Prepare for an unaligned write to a shared/cow page + * by copying the data before and after the range to be written. * @pos: address to do copy from. * @length: size of copy operation. * @align_size: aligned w.r.t align_size (either PMD_SIZE or PAGE_SIZE) @@ -1101,35 +1102,50 @@ out: * * This can be called from two places. Either during DAX write fault (page * aligned), to copy the length size data to daddr. Or, while doing normal DAX - * write operation, dax_iomap_actor() might call this to do the copy of either + * write operation, dax_iomap_iter() might call this to do the copy of either * start or end unaligned address. In the latter case the rest of the copy of - * aligned ranges is taken care by dax_iomap_actor() itself. + * aligned ranges is taken care by dax_iomap_iter() itself. + * If the srcmap contains invalid data, such as HOLE and UNWRITTEN, zero the + * area to make sure no old data remains. */ -static int dax_iomap_cow_copy(loff_t pos, uint64_t length, size_t align_size, +static int dax_iomap_copy_around(loff_t pos, uint64_t length, size_t align_size, const struct iomap *srcmap, void *daddr) { loff_t head_off = pos & (align_size - 1); size_t size = ALIGN(head_off + length, align_size); loff_t end = pos + length; loff_t pg_end = round_up(end, align_size); + /* copy_all is usually in page fault case */ bool copy_all = head_off == 0 && end == pg_end; + /* zero the edges if srcmap is a HOLE or IOMAP_UNWRITTEN */ + bool zero_edge = srcmap->flags & IOMAP_F_SHARED || + srcmap->type == IOMAP_UNWRITTEN; void *saddr = 0; int ret = 0; - ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL); - if (ret) - return ret; + if (!zero_edge) { + ret = dax_iomap_direct_access(srcmap, pos, size, &saddr, NULL); + if (ret) + return ret; + } if (copy_all) { - ret = copy_mc_to_kernel(daddr, saddr, length); - return ret ? -EIO : 0; + if (zero_edge) + memset(daddr, 0, size); + else + ret = copy_mc_to_kernel(daddr, saddr, length); + goto out; } /* Copy the head part of the range */ if (head_off) { - ret = copy_mc_to_kernel(daddr, saddr, head_off); - if (ret) - return -EIO; + if (zero_edge) + memset(daddr, 0, head_off); + else { + ret = copy_mc_to_kernel(daddr, saddr, head_off); + if (ret) + return -EIO; + } } /* Copy the tail part of the range */ @@ -1137,12 +1153,19 @@ static int dax_iomap_cow_copy(loff_t pos loff_t tail_off = head_off + length; loff_t tail_len = pg_end - end; - ret = copy_mc_to_kernel(daddr + tail_off, saddr + tail_off, - tail_len); - if (ret) - return -EIO; + if (zero_edge) + memset(daddr + tail_off, 0, tail_len); + else { + ret = copy_mc_to_kernel(daddr + tail_off, + saddr + tail_off, tail_len); + if (ret) + return -EIO; + } } - return 0; +out: + if (zero_edge) + dax_flush(srcmap->dax_dev, daddr, size); + return ret ? -EIO : 0; } /* @@ -1241,13 +1264,10 @@ static int dax_memzero(struct iomap_iter if (ret < 0) return ret; memset(kaddr + offset, 0, size); - if (srcmap->addr != iomap->addr) { - ret = dax_iomap_cow_copy(pos, size, PAGE_SIZE, srcmap, - kaddr); - if (ret < 0) - return ret; - dax_flush(iomap->dax_dev, kaddr, PAGE_SIZE); - } else + if (iomap->flags & IOMAP_F_SHARED) + ret = dax_iomap_copy_around(pos, size, PAGE_SIZE, srcmap, + kaddr); + else dax_flush(iomap->dax_dev, kaddr + offset, size); return ret; } @@ -1401,8 +1421,8 @@ static loff_t dax_iomap_iter(const struc } if (cow) { - ret = dax_iomap_cow_copy(pos, length, PAGE_SIZE, srcmap, - kaddr); + ret = dax_iomap_copy_around(pos, length, PAGE_SIZE, + srcmap, kaddr); if (ret) break; } @@ -1547,7 +1567,7 @@ static vm_fault_t dax_fault_iter(struct struct xa_state *xas, void **entry, bool pmd) { const struct iomap *iomap = &iter->iomap; - const struct iomap *srcmap = &iter->srcmap; + const struct iomap *srcmap = iomap_iter_srcmap(iter); size_t size = pmd ? PMD_SIZE : PAGE_SIZE; loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT; bool write = iter->flags & IOMAP_WRITE; @@ -1578,9 +1598,8 @@ static vm_fault_t dax_fault_iter(struct *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, entry_flags); - if (write && - srcmap->type != IOMAP_HOLE && srcmap->addr != iomap->addr) { - err = dax_iomap_cow_copy(pos, size, size, srcmap, kaddr); + if (write && iomap->flags & IOMAP_F_SHARED) { + err = dax_iomap_copy_around(pos, size, size, srcmap, kaddr); if (err) return dax_fault_return(err); } _ Patches currently in -mm which might be from ruansy.fnst@fujitsu.com are