From 103ec96b1336d3571b906a2d36b29e29df5e56fe Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 12 Jun 2012 16:20:29 +0200
Subject: [PATCH] --- yaml --- r: 320977 b: refs/heads/master c:
 4fcf1c6205fcfc7a226a144ae4d83b7f5415cab8 h: refs/heads/master i:   320975:
 6c5db1e1936cde51372c13c0eb5df1662aa160ad v: v3

---
 [refs]                   |  2 +-
 trunk/include/linux/mm.h |  1 +
 trunk/mm/filemap.c       | 19 +++++++++++++++++++
 trunk/mm/filemap_xip.c   |  1 +
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 7a14d733f0a5..5bcf7df6997e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 41c4d25f78c01ede13efee1f2e979f3f35dd26f6
+refs/heads/master: 4fcf1c6205fcfc7a226a144ae4d83b7f5415cab8
diff --git a/trunk/include/linux/mm.h b/trunk/include/linux/mm.h
index b36d08ce5c57..15987d8e1d59 100644
--- a/trunk/include/linux/mm.h
+++ b/trunk/include/linux/mm.h
@@ -1411,6 +1411,7 @@ extern void truncate_inode_pages_range(struct address_space *,
 
 /* generic vm_area_ops exported for stackable file systems */
 extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
+extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 
 /* mm/page-writeback.c */
 int write_one_page(struct page *page, int wait);
diff --git a/trunk/mm/filemap.c b/trunk/mm/filemap.c
index a4a5260b0279..51efee65c2cc 100644
--- a/trunk/mm/filemap.c
+++ b/trunk/mm/filemap.c
@@ -1712,8 +1712,27 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 }
 EXPORT_SYMBOL(filemap_fault);
 
+int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct page *page = vmf->page;
+	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+	int ret = VM_FAULT_LOCKED;
+
+	file_update_time(vma->vm_file);
+	lock_page(page);
+	if (page->mapping != inode->i_mapping) {
+		unlock_page(page);
+		ret = VM_FAULT_NOPAGE;
+		goto out;
+	}
+out:
+	return ret;
+}
+EXPORT_SYMBOL(filemap_page_mkwrite);
+
 const struct vm_operations_struct generic_file_vm_ops = {
 	.fault		= filemap_fault,
+	.page_mkwrite	= filemap_page_mkwrite,
 };
 
 /* This is used for a general mmap of a disk file */
diff --git a/trunk/mm/filemap_xip.c b/trunk/mm/filemap_xip.c
index 213ca1f53409..80b34ef82dfe 100644
--- a/trunk/mm/filemap_xip.c
+++ b/trunk/mm/filemap_xip.c
@@ -304,6 +304,7 @@ static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 static const struct vm_operations_struct xip_file_vm_ops = {
 	.fault	= xip_file_fault,
+	.page_mkwrite	= filemap_page_mkwrite,
 };
 
 int xip_file_mmap(struct file * file, struct vm_area_struct * vma)