From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935577AbcA0TEO (ORCPT ); Wed, 27 Jan 2016 14:04:14 -0500 Received: from mga02.intel.com ([134.134.136.20]:1668 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934459AbcA0TC7 (ORCPT ); Wed, 27 Jan 2016 14:02:59 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,356,1449561600"; d="scan'208";a="870032685" From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , "Theodore Ts'o" , Dan Williams , Jan Kara , Matthew Wilcox , linux-ext4@vger.kernel.org, linux-nvdimm@ml01.01.org Subject: [PATCH] ext2, ext4: Fix issue with missing journal entry Date: Wed, 27 Jan 2016 12:01:48 -0700 Message-Id: <1453921308-5544-1-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As it is currently written ext4_dax_mkwrite() assumes that the call into __dax_mkwrite() will not have to do a block allocation so it doesn't create a journal entry. For a read that creates a zero page to cover a hole followed by a write that actually allocates storage this is incorrect. The ext4_dax_mkwrite() -> __dax_mkwrite() -> __dax_fault() path calls get_blocks() to allocate storage. Fix this by having the ->page_mkwrite fault handler call ext4_dax_fault() as this function already has all the logic needed to allocate a journal entry and call __dax_fault(). Also update the ext2 fault handlers in this same way to remove duplicate code and keep the logic between ext2 and ext4 the same. Signed-off-by: Ross Zwisler --- fs/ext2/file.c | 19 +------------------ fs/ext4/file.c | 19 ++----------------- 2 files changed, 3 insertions(+), 35 deletions(-) diff --git a/fs/ext2/file.c b/fs/ext2/file.c index 2c88d68..c1400b1 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -80,23 +80,6 @@ static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, return ret; } -static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) -{ - struct inode *inode = file_inode(vma->vm_file); - struct ext2_inode_info *ei = EXT2_I(inode); - int ret; - - sb_start_pagefault(inode->i_sb); - file_update_time(vma->vm_file); - down_read(&ei->dax_sem); - - ret = __dax_mkwrite(vma, vmf, ext2_get_block, NULL); - - up_read(&ei->dax_sem); - sb_end_pagefault(inode->i_sb); - return ret; -} - static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) { @@ -124,7 +107,7 @@ static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma, static const struct vm_operations_struct ext2_dax_vm_ops = { .fault = ext2_dax_fault, .pmd_fault = ext2_dax_pmd_fault, - .page_mkwrite = ext2_dax_mkwrite, + .page_mkwrite = ext2_dax_fault, .pfn_mkwrite = ext2_dax_pfn_mkwrite, }; diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 1126436..d2e8500 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -262,23 +262,8 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, return result; } -static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) -{ - int err; - struct inode *inode = file_inode(vma->vm_file); - - sb_start_pagefault(inode->i_sb); - file_update_time(vma->vm_file); - down_read(&EXT4_I(inode)->i_mmap_sem); - err = __dax_mkwrite(vma, vmf, ext4_dax_mmap_get_block, NULL); - up_read(&EXT4_I(inode)->i_mmap_sem); - sb_end_pagefault(inode->i_sb); - - return err; -} - /* - * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_mkwrite() + * Handle write fault for VM_MIXEDMAP mappings. Similarly to ext4_dax_fault() * handler we check for races agaist truncate. Note that since we cycle through * i_mmap_sem, we are sure that also any hole punching that began before we * were called is finished by now and so if it included part of the file we @@ -311,7 +296,7 @@ static int ext4_dax_pfn_mkwrite(struct vm_area_struct *vma, static const struct vm_operations_struct ext4_dax_vm_ops = { .fault = ext4_dax_fault, .pmd_fault = ext4_dax_pmd_fault, - .page_mkwrite = ext4_dax_mkwrite, + .page_mkwrite = ext4_dax_fault, .pfn_mkwrite = ext4_dax_pfn_mkwrite, }; #else -- 2.5.0