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authorBoaz Harrosh <boaz@plexistor.com>2015-04-16 01:15:14 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-16 01:35:20 +0200
commit0e3b210ce1722168227cb3bc7746256d0c0afece (patch)
tree61e29f2d7d7c5e12029cafcbb0c42165a2cc1f20 /fs
parentmm: new pfn_mkwrite same as page_mkwrite for VM_PFNMAP (diff)
downloadlinux-0e3b210ce1722168227cb3bc7746256d0c0afece.tar.xz
linux-0e3b210ce1722168227cb3bc7746256d0c0afece.zip
dax: use pfn_mkwrite to update c/mtime + freeze protection
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/dax.c17
-rw-r--r--fs/ext2/file.c1
-rw-r--r--fs/ext4/file.c1
3 files changed, 19 insertions, 0 deletions
diff --git a/fs/dax.c b/fs/dax.c
index ed1619ec6537..d0bd1f4f81b3 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 e31701713516..866a3ce3f864 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 598abbbe6786..aa78c70553f4 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