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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DBF5C43381 for ; Tue, 26 Mar 2019 19:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CBFB20823 for ; Tue, 26 Mar 2019 19:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732660AbfCZTDg (ORCPT ); Tue, 26 Mar 2019 15:03:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:37008 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732504AbfCZTDe (ORCPT ); Tue, 26 Mar 2019 15:03:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4BBC0AF79; Tue, 26 Mar 2019 19:03:33 +0000 (UTC) From: Goldwyn Rodrigues To: linux-btrfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Goldwyn Rodrigues Subject: [PATCH 08/15] dax: add dax_iomap_cow to copy a mmap page before writing Date: Tue, 26 Mar 2019 14:02:54 -0500 Message-Id: <20190326190301.32365-9-rgoldwyn@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190326190301.32365-1-rgoldwyn@suse.de> References: <20190326190301.32365-1-rgoldwyn@suse.de> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Goldwyn Rodrigues dax_iomap_cow copies a page before presenting for mmap. Signed-off-by: Goldwyn Rodrigues --- fs/dax.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index e254535dd830..21ee3df6f02c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1269,6 +1269,33 @@ static bool dax_fault_is_synchronous(unsigned long flags, && (iomap->flags & IOMAP_F_DIRTY); } +static int dax_iomap_cow(struct iomap *iomap, loff_t pos, pfn_t *pfn) +{ + void *daddr; + pgoff_t pgoff; + long rc; + int id; + sector_t sector; + + pos = round_down(pos, PAGE_SIZE); + + sector = round_down(iomap->addr + iomap->offset - pos, PAGE_SIZE) >> 9; + rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff); + if (rc) + return rc; + + id = dax_read_lock(); + rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &daddr, pfn); + if (rc < 0) + goto out; + + dax_to_dax_copy(iomap, pos, daddr, PAGE_SIZE); + +out: + dax_read_unlock(id); + return rc; +} + static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) { @@ -1372,7 +1399,11 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); major = VM_FAULT_MAJOR; } - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); + + if (iomap.flags & IOMAP_F_COW) + error = dax_iomap_cow(&iomap, pos, &pfn); + else + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); if (error < 0) goto error_finish_iomap; -- 2.16.4