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From: Boaz Harrosh <boaz@plexistor.com>
To: Dave Chinner <david@fromorbit.com>,
	Matthew Wilcox <matthew.r.wilcox@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Jan Kara <jack@suse.cz>, Hugh Dickins <hughd@google.com>,
	Mel Gorman <mgorman@suse.de>,
	linux-mm@kvack.org, linux-nvdimm <linux-nvdimm@ml01.01.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Eryu Guan <eguan@redhat.com>
Subject: [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze protection
Date: Mon, 23 Mar 2015 14:52:35 +0200	[thread overview]
Message-ID: <55100C93.9040607@plexistor.com> (raw)
In-Reply-To: <55100B78.501@plexistor.com>

From: Yigal Korman <yigal@plexistor.com>

[v1]
Without this patch, c/mtime is not updated correctly when mmap'ed page is
first read from and then written to.

A new xfstest is submitted for testing this (generic/080)

[v2]
Jan Kara has pointed out that if we add the
sb_start/end_pagefault pair in the new pfn_mkwrite we
are then fixing another bug where: A user could start
writing to the page while filesystem is frozen.

CC: Jan Kara <jack@suse.cz>
CC: Matthew Wilcox <matthew.r.wilcox@intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yigal Korman <yigal@plexistor.com>
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
---
 fs/dax.c           | 17 +++++++++++++++++
 fs/ext2/file.c     |  1 +
 fs/ext4/file.c     |  1 +
 include/linux/fs.h |  1 +
 4 files changed, 20 insertions(+)

diff --git a/fs/dax.c b/fs/dax.c
index ed1619e..d0bd1f4 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -464,6 +464,23 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 EXPORT_SYMBOL_GPL(dax_fault);
 
 /**
+ * dax_pfn_mkwrite - handle first write to DAX page
+ * @vma: The virtual memory area where the fault occurred
+ * @vmf: The description of the fault
+ *
+ */
+int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+
+	sb_start_pagefault(sb);
+	file_update_time(vma->vm_file);
+	sb_end_pagefault(sb);
+	return VM_FAULT_NOPAGE;
+}
+EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);
+
+/**
  * dax_zero_page_range - zero a range within a page of a DAX file
  * @inode: The file being truncated
  * @from: The file offset that is being truncated to
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
index e317017..866a3ce 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -39,6 +39,7 @@ static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 static const struct vm_operations_struct ext2_dax_vm_ops = {
 	.fault		= ext2_dax_fault,
 	.page_mkwrite	= ext2_dax_mkwrite,
+	.pfn_mkwrite	= dax_pfn_mkwrite,
 };
 
 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 33a09da..b43a7a6 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -206,6 +206,7 @@ static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 static const struct vm_operations_struct ext4_dax_vm_ops = {
 	.fault		= ext4_dax_fault,
 	.page_mkwrite	= ext4_dax_mkwrite,
+	.pfn_mkwrite	= dax_pfn_mkwrite,
 };
 #else
 #define ext4_dax_vm_ops	ext4_file_vm_ops
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b4d71b5..24af817 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2597,6 +2597,7 @@ int dax_clear_blocks(struct inode *, sector_t block, long size);
 int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
 int dax_truncate_page(struct inode *, loff_t from, get_block_t);
 int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t);
+int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
 #define dax_mkwrite(vma, vmf, gb)	dax_fault(vma, vmf, gb)
 
 #ifdef CONFIG_BLOCK
-- 
1.9.3

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  parent reply	other threads:[~2015-03-23 12:52 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-23 12:47 [PATCH 0/3 v3] dax: Fix mmap-write not updating c/mtime Boaz Harrosh
2015-03-23 12:47 ` Boaz Harrosh
2015-03-23 12:49 ` [PATCH 1/3] mm: New pfn_mkwrite same as page_mkwrite for VM_PFNMAP Boaz Harrosh
2015-03-23 22:49   ` Andrew Morton
2015-03-23 22:49     ` Andrew Morton
2015-03-23 12:52 ` Boaz Harrosh [this message]
2015-03-23 12:54 ` [PATCH 3/3] RFC: dax: dax_prepare_freeze Boaz Harrosh
2015-03-23 22:40   ` Dave Chinner
2015-03-23 22:40     ` Dave Chinner
2015-03-24  6:14     ` Boaz Harrosh
2015-03-24  6:14       ` Boaz Harrosh
2015-03-25  2:22       ` Dave Chinner
2015-03-25  2:22         ` Dave Chinner
2015-03-25  8:10         ` Boaz Harrosh
2015-03-25  9:29           ` Dave Chinner
2015-03-25  9:29             ` Dave Chinner
2015-03-25 10:19             ` Boaz Harrosh
2015-03-25 10:19               ` Boaz Harrosh
2015-03-25 20:00               ` Dave Chinner
2015-03-25 20:00                 ` Dave Chinner
2015-03-26  8:02                 ` Boaz Harrosh
2015-03-26 20:58                   ` Dave Chinner
2015-03-26 20:58                     ` Dave Chinner
2015-03-24 12:37   ` Boaz Harrosh
2015-03-24 12:37     ` Boaz Harrosh
2015-03-25  2:26     ` Dave Chinner
2015-03-25  2:26       ` Dave Chinner
2015-03-25  8:31       ` Boaz Harrosh
2015-03-25  8:31         ` Boaz Harrosh
2015-03-25  9:41         ` Dave Chinner
2015-03-25  9:41           ` Dave Chinner
2015-03-25 10:40           ` Boaz Harrosh
2015-03-25 10:40             ` Boaz Harrosh
2015-03-25 20:05             ` Dave Chinner
2015-03-25 20:05               ` Dave Chinner
2015-03-23 12:56 ` [PATCH v4] xfstest: generic/080 test that mmap-write updates c/mtime Boaz Harrosh
2015-04-07  8:33 [PATCH 0/3 v5] dax: some dax fixes and cleanups Boaz Harrosh
2015-04-07  8:43 ` [PATCH 2/3] dax: use pfn_mkwrite to update c/mtime + freeze protection Boaz Harrosh
2015-04-07  8:43   ` Boaz Harrosh
2015-04-07 16:28   ` Jan Kara
2015-04-07 16:28     ` Jan Kara

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