7 files changed, 27 insertions, 5 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 7a75c3e0fd58..2ea9cd44aeae 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2359,7 +2359,7 @@ int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
         if (unlikely(ret < 0))
                 goto out_unlock;
         set_page_dirty(page);
-        wait_on_page_writeback(page);
+        wait_for_stable_page(page);
         return 0;
 out_unlock:
         unlock_page(page);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cbfe13bf5b2a..cd818d8bb221 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4968,7 +4968,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
                                             0, len, NULL,
                                             ext4_bh_unmapped)) {
                         /* Wait so that we don't change page under IO */
-                        wait_on_page_writeback(page);
+                        wait_for_stable_page(page);
                         ret = VM_FAULT_LOCKED;
                         goto out;
                 }
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 06b7092a3f25..2687f50d98cb 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -483,7 +483,7 @@ out:
         gfs2_holder_uninit(&gh);
         if (ret == 0) {
                 set_page_dirty(page);
-                wait_on_page_writeback(page);
+                wait_for_stable_page(page);
         }
         sb_end_pagefault(inode->i_sb);
         return block_page_mkwrite_return(ret);
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 61946883025c..bec4af6eab13 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -126,7 +126,7 @@ static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         nilfs_transaction_commit(inode->i_sb);
 
  mapped:
-        wait_on_page_writeback(page);
+        wait_for_stable_page(page);
  out:
         sb_end_pagefault(inode->i_sb);
         return block_page_mkwrite_return(ret);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 6da609d14c15..0e38e13eb249 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -414,6 +414,7 @@ static inline void wait_on_page_writeback(struct page *page)
 }
 
 extern void end_page_writeback(struct page *page);
+void wait_for_stable_page(struct page *page);
 
 /*
  * Add an arbitrary waiter to a page's wait queue
diff --git a/mm/filemap.c b/mm/filemap.c
index 24a7ea583f0c..c610076c30e1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1728,6 +1728,7 @@ int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
          * see the dirty page and writeprotect it again.
          */
         set_page_dirty(page);
+        wait_for_stable_page(page);
 out:
         sb_end_pagefault(inode->i_sb);
         return ret;
@@ -2274,7 +2275,7 @@ repeat:
                 return NULL;
         }
 found:
-        wait_on_page_writeback(page);
+        wait_for_stable_page(page);
         return page;
 }
 EXPORT_SYMBOL(grab_cache_page_write_begin);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 66a0024becd9..355d5ee69058 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2290,3 +2290,23 @@ int mapping_tagged(struct address_space *mapping, int tag)
         return radix_tree_tagged(&mapping->page_tree, tag);
 }
 EXPORT_SYMBOL(mapping_tagged);
+
+/**
+ * wait_for_stable_page() - wait for writeback to finish, if necessary.
+ * @page:       The page to wait on.
+ *
+ * This function determines if the given page is related to a backing device
+ * that requires page contents to be held stable during writeback.  If so, then
+ * it will wait for any pending writeback to complete.
+ */
+void wait_for_stable_page(struct page *page)
+{
+        struct address_space *mapping = page_mapping(page);
+        struct backing_dev_info *bdi = mapping->backing_dev_info;
+
+        if (!bdi_cap_stable_pages_required(bdi))
+                return;
+
+        wait_on_page_writeback(page);
+}
+EXPORT_SYMBOL_GPL(wait_for_stable_page);