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dax: use pfn_mkwrite to update c/mtime + freeze protection

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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.

Signed-off-by: Yigal Korman <yigal@plexistor.com>
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Boaz Harrosh 2015-04-15 16:15:14 -07:00 committed by Linus Torvalds
parent dd9061846a
commit 0e3b210ce1
4 changed files with 20 additions and 0 deletions
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17
fs/dax.c
View File

@ -463,6 +463,23 @@ 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

1
fs/ext2/file.c
View File

@ -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)

1
fs/ext4/file.c
View File

@ -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

1
include/linux/fs.h
View File

@ -2620,6 +2620,7 @@ 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