From 0e3b210ce1722168227cb3bc7746256d0c0afece Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Wed, 15 Apr 2015 16:15:14 -0700 Subject: dax: use pfn_mkwrite to update c/mtime + freeze protection From: Yigal Korman [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 Signed-off-by: Boaz Harrosh Reviewed-by: Jan Kara Cc: Matthew Wilcox Cc: Dave Chinner Cc: Hugh Dickins Cc: Mel Gorman Cc: Kirill A. Shutemov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/dax.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'fs/dax.c') diff --git a/fs/dax.c b/fs/dax.c index ed1619ec6537..d0bd1f4f81b3 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -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 -- cgit v1.2.3-55-g7522