From patchwork Fri Aug 7 13:13:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruan Shiyang X-Patchwork-Id: 11705649 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 83DCE138C for ; Fri, 7 Aug 2020 13:13:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5B535221E2 for ; Fri, 7 Aug 2020 13:13:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B535221E2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cn.fujitsu.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7F04C8D00A3; Fri, 7 Aug 2020 09:13:53 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 7A26A8D003B; Fri, 7 Aug 2020 09:13:53 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6DF7F8D00A3; Fri, 7 Aug 2020 09:13:53 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0124.hostedemail.com [216.40.44.124]) by kanga.kvack.org (Postfix) with ESMTP id 5A6558D003B for ; Fri, 7 Aug 2020 09:13:53 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 18F6740DD for ; Fri, 7 Aug 2020 13:13:53 +0000 (UTC) X-FDA: 77123815146.27.edge63_5504c4d26fc0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id DD8AD3D663 for ; Fri, 7 Aug 2020 13:13:52 +0000 (UTC) X-Spam-Summary: 1,0,0,c72538f2c7290857,d41d8cd98f00b204,ruansy.fnst@cn.fujitsu.com,,RULES_HIT:41:355:379:541:800:960:973:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1535:1543:1711:1730:1747:1777:1792:2393:2559:2562:3138:3139:3140:3141:3142:3354:3865:3866:3867:3870:3871:3874:5007:6117:6120:6261:8603:10004:10400:11026:11473:11537:11658:11914:12043:12291:12296:12297:12438:12521:12555:12683:12895:13019:13894:14096:14097:14110:14181:14721:21080:21325:21451:21611:21627:21990:30054:30070,0,RBL:183.91.158.132:@cn.fujitsu.com:.lbl8.mailshell.net-62.16.2.100 64.201.201.201;04y8m38z4zxf45rqgw4wf91cao7kuycxe1e15qgkryzi1cbc7fr9n3aetpcksqm.4j41tuduombjeu1jerrkmjimj41ft6uujzrirqe4iz9xxg1a5c6a5mnxsjdsh1g.n-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: edge63_5504c4d26fc0 X-Filterd-Recvd-Size: 5755 Received: from heian.cn.fujitsu.com (mail.cn.fujitsu.com [183.91.158.132]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Fri, 7 Aug 2020 13:13:50 +0000 (UTC) X-IronPort-AV: E=Sophos;i="5.75,445,1589212800"; d="scan'208";a="97774909" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 07 Aug 2020 21:13:42 +0800 Received: from G08CNEXMBPEKD04.g08.fujitsu.local (unknown [10.167.33.201]) by cn.fujitsu.com (Postfix) with ESMTP id 349484CE38A0; Fri, 7 Aug 2020 21:13:40 +0800 (CST) Received: from G08CNEXCHPEKD06.g08.fujitsu.local (10.167.33.205) by G08CNEXMBPEKD04.g08.fujitsu.local (10.167.33.201) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 7 Aug 2020 21:13:42 +0800 Received: from localhost.localdomain (10.167.225.141) by G08CNEXCHPEKD06.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Fri, 7 Aug 2020 21:13:40 +0800 From: Shiyang Ruan To: , , CC: , , , , , , , , , Goldwyn Rodrigues Subject: [RFC PATCH 5/8] fsdax: replace mmap entry in case of CoW Date: Fri, 7 Aug 2020 21:13:33 +0800 Message-ID: <20200807131336.318774-6-ruansy.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200807131336.318774-1-ruansy.fnst@cn.fujitsu.com> References: <20200807131336.318774-1-ruansy.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-yoursite-MailScanner-ID: 349484CE38A0.AAB17 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: ruansy.fnst@cn.fujitsu.com X-Spam-Status: No X-Rspamd-Queue-Id: DD8AD3D663 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: We replace the existing entry to the newly allocated one in case of CoW. Also, we mark the entry as PAGECACHE_TAG_TOWRITE so writeback marks this entry as writeprotected. This helps us snapshots so new write pagefaults after snapshots trigger a CoW. Signed-off-by: Goldwyn Rodrigues Signed-off-by: Shiyang Ruan --- fs/dax.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 65553e3f7602..28b8e23b11ac 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -766,6 +766,9 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, return 0; } +#define DAX_IF_DIRTY (1ULL << 0) +#define DAX_IF_COW (1ULL << 1) + /* * By this point grab_mapping_entry() has ensured that we have a locked entry * of the appropriate size so we don't have to worry about downgrading PMDs to @@ -776,14 +779,16 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, static void *dax_insert_entry(struct xa_state *xas, struct address_space *mapping, struct vm_fault *vmf, pgoff_t bdoff, void *entry, pfn_t pfn, unsigned long flags, - bool dirty) + bool insert_flags) { void *new_entry = dax_make_entry(pfn, flags); + bool dirty = insert_flags & DAX_IF_DIRTY; + bool cow = insert_flags & DAX_IF_COW; if (dirty) __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); - if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) { + if (cow || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) { unsigned long index = xas->xa_index; /* we are replacing a zero page with block mapping */ if (dax_is_pmd_entry(entry)) @@ -795,7 +800,7 @@ static void *dax_insert_entry(struct xa_state *xas, xas_reset(xas); xas_lock_irq(xas); - if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { + if (cow || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { void *old; dax_disassociate_entry(entry, mapping, false); @@ -819,6 +824,9 @@ static void *dax_insert_entry(struct xa_state *xas, if (dirty) xas_set_mark(xas, PAGECACHE_TAG_DIRTY); + if (cow) + xas_set_mark(xas, PAGECACHE_TAG_TOWRITE); + xas_unlock_irq(xas); return entry; } @@ -1366,6 +1374,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, void *entry; pfn_t pfn; void *kaddr; + unsigned long insert_flags = 0; trace_dax_pte_fault(inode, vmf, ret); /* @@ -1491,8 +1500,10 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, goto finish_iomap; case IOMAP_UNWRITTEN: - if (write && iomap.flags & IOMAP_F_SHARED) + if (write && (iomap.flags & IOMAP_F_SHARED)) { + insert_flags |= DAX_IF_COW; goto cow; + } fallthrough; case IOMAP_HOLE: if (!write) { @@ -1602,6 +1613,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, int error; pfn_t pfn; void *kaddr; + unsigned long insert_flags = 0; /* * Check whether offset isn't beyond end of file now. Caller is @@ -1717,14 +1729,17 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, result = vmf_insert_pfn_pmd(vmf, pfn, write); break; case IOMAP_UNWRITTEN: - if (write && iomap.flags & IOMAP_F_SHARED) + if (write && (iomap.flags & IOMAP_F_SHARED)) { + insert_flags |= DAX_IF_COW; goto cow; + } fallthrough; case IOMAP_HOLE: - if (WARN_ON_ONCE(write)) + if (!write) { + result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry); break; - result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry); - break; + } + fallthrough; default: WARN_ON_ONCE(1); break;