From patchwork Tue Sep 27 16:08:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 9352279 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B4DAA608A0 for ; Tue, 27 Sep 2016 16:08:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A6743286CD for ; Tue, 27 Sep 2016 16:08:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9B1F928979; Tue, 27 Sep 2016 16:08:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3D12029296 for ; Tue, 27 Sep 2016 16:08:54 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id D3AB41A1EA1; Tue, 27 Sep 2016 09:08:41 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 44F731A1E26 for ; Tue, 27 Sep 2016 09:08:37 -0700 (PDT) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B25C27502E; Tue, 27 Sep 2016 16:08:32 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 21ED01E11BB; Tue, 27 Sep 2016 18:08:31 +0200 (CEST) From: Jan Kara To: linux-mm@kvack.org Subject: [PATCH 20/20] dax: Clear dirty entry tags on cache flush Date: Tue, 27 Sep 2016 18:08:24 +0200 Message-Id: <1474992504-20133-21-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.6 In-Reply-To: <1474992504-20133-1-git-send-email-jack@suse.cz> References: <1474992504-20133-1-git-send-email-jack@suse.cz> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jan Kara , linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, "Kirill A. Shutemov" MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP Currently we never clear dirty tags in DAX mappings and thus address ranges to flush accumulate. Now that we have locking of radix tree entries, we have all the locking necessary to reliably clear the radix tree dirty tag when flushing caches for corresponding address range. Similarly to page_mkclean() we also have to write-protect pages to get a page fault when the page is next written to so that we can mark the entry dirty again. Signed-off-by: Jan Kara Reviewed-by: Ross Zwisler --- fs/dax.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/fs/dax.c b/fs/dax.c index a2d3781c9f4e..233f548d298e 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "internal.h" @@ -668,6 +669,59 @@ static void *dax_insert_mapping_entry(struct address_space *mapping, return new_entry; } +static inline unsigned long +pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) +{ + unsigned long address; + + address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); + return address; +} + +/* Walk all mappings of a given index of a file and writeprotect them */ +static void dax_mapping_entry_mkclean(struct address_space *mapping, + pgoff_t index, unsigned long pfn) +{ + struct vm_area_struct *vma; + pte_t *ptep; + pte_t pte; + spinlock_t *ptl; + bool changed; + + i_mmap_lock_read(mapping); + vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { + unsigned long address; + + cond_resched(); + + if (!(vma->vm_flags & VM_SHARED)) + continue; + + address = pgoff_address(index, vma); + changed = false; + if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) + continue; + if (pfn != pte_pfn(*ptep)) + goto unlock; + if (!pte_dirty(*ptep) && !pte_write(*ptep)) + goto unlock; + + flush_cache_page(vma, address, pfn); + pte = ptep_clear_flush(vma, address, ptep); + pte = pte_wrprotect(pte); + pte = pte_mkclean(pte); + set_pte_at(vma->vm_mm, address, ptep, pte); + changed = true; +unlock: + pte_unmap_unlock(ptep, ptl); + + if (changed) + mmu_notifier_invalidate_page(vma->vm_mm, address); + } + i_mmap_unlock_read(mapping); +} + static int dax_writeback_one(struct block_device *bdev, struct address_space *mapping, pgoff_t index, void *entry) { @@ -735,7 +789,17 @@ static int dax_writeback_one(struct block_device *bdev, goto unmap; } + dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(dax.pfn)); wb_cache_pmem(dax.addr, dax.size); + /* + * After we have flushed the cache, we can clear the dirty tag. There + * cannot be new dirty data in the pfn after the flush has completed as + * the pfn mappings are writeprotected and fault waits for mapping + * entry lock. + */ + spin_lock_irq(&mapping->tree_lock); + radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); + spin_unlock_irq(&mapping->tree_lock); unmap: dax_unmap_atomic(bdev, &dax); put_locked_mapping_entry(mapping, index, entry);