From: Boaz Harrosh <[email protected]> Subject: dax: use pfn_mkwrite to update c/mtime + freeze protection
From: Yigal Korman <[email protected]> [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 <[email protected]> Signed-off-by: Boaz Harrosh <[email protected]> Reviewed-by: Jan Kara <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Dave Chinner <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- 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 -puN fs/dax.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection fs/dax.c --- a/fs/dax.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection +++ a/fs/dax.c @@ -464,6 +464,23 @@ int dax_fault(struct vm_area_struct *vma 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 -puN fs/ext2/file.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection fs/ext2/file.c --- a/fs/ext2/file.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection +++ a/fs/ext2/file.c @@ -39,6 +39,7 @@ static int ext2_dax_mkwrite(struct vm_ar 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 -puN fs/ext4/file.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection fs/ext4/file.c --- a/fs/ext4/file.c~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection +++ a/fs/ext4/file.c @@ -206,6 +206,7 @@ static int ext4_dax_mkwrite(struct vm_ar 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 -puN include/linux/fs.h~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection include/linux/fs.h --- a/include/linux/fs.h~dax-use-pfn_mkwrite-to-update-c-mtime-freeze-protection +++ a/include/linux/fs.h @@ -2620,6 +2620,7 @@ int dax_clear_blocks(struct inode *, sec 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 _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
