From patchwork Fri Dec 2 09:25:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shiyang Ruan X-Patchwork-Id: 13062465 Received: from mail1.bemta34.messagelabs.com (mail1.bemta34.messagelabs.com [195.245.231.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3B2A1C2B for ; Fri, 2 Dec 2022 09:26:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fujitsu.com; s=170520fj; t=1669973161; i=@fujitsu.com; bh=7Gh67qKW0EaWHKgn5AoVn9psrj7yKSlvOKC1gXmit9M=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Qmosm8omzUsPVuQCzidCKcRa1vj79KIdvtncPuVfSzeuswDyAZVAFeDr/ngYEZDXM okkQDpjpswGK7+FQEmbkQeN/E5sgSHPBYwUKN1V2Hhp6fE/z4S+KEwwnxuV8H1zyMg im0gMBXDqJSHGYt/co6N2TrC3CQBzfyVXgq5+w0SN9LMonyPVfOGCDoFX9+2EJBe6b 0ad7azCsjQX5lGzPWK+50ZnsfCfq5ux9jzkTfP/QUDynz68GzSUuhH3cdZ9BtrIoaz 5+5kbgCx2kXsebs/CH4yxEe14du+FRFTSdlsxPAuyTi2tEFD3JSlCW7ktB9TJEXLxs qWmBqE93vJbRw== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrHIsWRWlGSWpSXmKPExsViZ8MxSXfFkc5 kg46dUhZz1q9hs5g+9QKjxZZj9xgtLj/hs9iz9ySLxeVdc9gsdv3ZwW6x8scfVgcOj1OLJDwW 73nJ5LFpVSebx4kZv1k8XmyeyejxeZNcAFsUa2ZeUn5FAmvGhVVn2At6dCp2zP7J3MB4TLmLk YtDSGALo8TOQ6dYIJzlTBInO06wQTh7GCWar9wEynBysAnoSFxY8Je1i5GDQ0SgWuLWUjaQML NAhsTxK3+YQWxhAT+Jzb/XgMVZBFQk1j85xgRi8wq4Ssz8fw7MlhBQkJjy8D1YPSdQfNv8t4w gtpCAi8Sej0eZIeoFJU7OfMICMV9C4uCLF8wgayUElCRmdsdDjKmQmDWrDWqkmsTVc5uYJzAK zkLSPQtJ9wJGplWMZsWpRWWpRbqGlnpJRZnpGSW5iZk5eolVuol6qaW65anFJbpGeonlxXqpx cV6xZW5yTkpenmpJZsYgdGSUqy4bgfj9GV/9A4xSnIwKYnyvlrWmSzEl5SfUpmRWJwRX1Sak1 p8iFGGg0NJgpf1AFBOsCg1PbUiLTMHGLkwaQkOHiUR3vd7gdK8xQWJucWZ6RCpU4yKUuK8uw4 BJQRAEhmleXBtsGRxiVFWSpiXkYGBQYinILUoN7MEVf4VozgHo5Iwb/U+oCk8mXklcNNfAS1m AlocKdYGsrgkESEl1cBU8f26R3/gQ42ZcpdeOc3wZHx78PmmVZ4yxwJy1TyvvZyms/V/6v06v fNnd8wLPn1o1dbXbJxXrj2+yc7AceBnIdPp53tsFp3mNLxwwO2U5pujko9b5rxmmX7+RVnkjH 8zBWp1chM7ig+nMXEdeXiqTO64n+KxfcpzFhUnNUvXeWrWVf+4YS7n2Xjop6Fpdoh7ff5ni4D ff279P6y1XXKWaOCkDZ5/nrhcj9/UoMp5quiGlYmbwJKuK/1fZ0rcffAgoFs/PvKs2+932ZfX KEqyS/rcWvozkHENp4q+ds3+nNSF0Vc+2ff6J80TP3xj7o+tnA13/7qEXZ7Ufiro9OQs81OzT l3y/uDJXnnA1O+jsBJLcUaioRZzUXEiAFCjZoWRAwAA X-Env-Sender: ruansy.fnst@fujitsu.com X-Msg-Ref: server-9.tower-571.messagelabs.com!1669973160!153515!1 X-Originating-IP: [62.60.8.146] X-SYMC-ESS-Client-Auth: outbound-route-from=pass X-StarScan-Received: X-StarScan-Version: 9.101.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 7087 invoked from network); 2 Dec 2022 09:26:00 -0000 Received: from unknown (HELO n03ukasimr02.n03.fujitsu.local) (62.60.8.146) by server-9.tower-571.messagelabs.com with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 2 Dec 2022 09:26:00 -0000 Received: from n03ukasimr02.n03.fujitsu.local (localhost [127.0.0.1]) by n03ukasimr02.n03.fujitsu.local (Postfix) with ESMTP id 1B5471000D7; Fri, 2 Dec 2022 09:26:00 +0000 (GMT) Received: from R01UKEXCASM126.r01.fujitsu.local (R01UKEXCASM126 [10.183.43.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by n03ukasimr02.n03.fujitsu.local (Postfix) with ESMTPS id 0E01B1000D5; Fri, 2 Dec 2022 09:26:00 +0000 (GMT) Received: from localhost.localdomain (10.167.225.141) by R01UKEXCASM126.r01.fujitsu.local (10.183.43.178) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Fri, 2 Dec 2022 09:25:56 +0000 From: Shiyang Ruan To: , , , CC: , , , Subject: [PATCH v2.1 3/8] fsdax: zero the edges if source is HOLE or UNWRITTEN Date: Fri, 2 Dec 2022 09:25:45 +0000 Message-ID: <1669973145-318-1-git-send-email-ruansy.fnst@fujitsu.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1669908538-55-4-git-send-email-ruansy.fnst@fujitsu.com> References: <1669908538-55-4-git-send-email-ruansy.fnst@fujitsu.com> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Originating-IP: [10.167.225.141] X-ClientProxiedBy: G08CNEXCHPEKD07.g08.fujitsu.local (10.167.33.80) To R01UKEXCASM126.r01.fujitsu.local (10.183.43.178) X-Virus-Scanned: ClamAV using ClamSMTP 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 copys data around the range. Signed-off-by: Shiyang Ruan Reviewed-by: Darrick J. Wong Reviewed-by: Allison Henderson --- fs/dax.c | 79 +++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 49 insertions(+), 30 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index a77739f2abe7..f12645d6f3c8 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1092,7 +1092,8 @@ static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos, } /** - * 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 @@ static int dax_iomap_direct_access(const struct iomap *iomap, loff_t pos, * * 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, uint64_t length, size_t align_size, 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 *iter, loff_t pos, size_t size) 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 struct iomap_iter *iomi, } 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 vm_fault *vmf, 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 vm_fault *vmf, *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); }