1 files changed, 30 insertions, 3 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a4373db5967..42bf9916805 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -307,9 +307,7 @@ int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
                 goto err;
         }
         found_level = btrfs_header_level(eb);
-        spin_lock(&root->fs_info->hash_lock);
-        btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
-        spin_unlock(&root->fs_info->hash_lock);
+
         csum_tree_block(root, eb, 0);
 err:
         free_extent_buffer(eb);
@@ -1998,7 +1996,36 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
         return ret;
 }
 
+int btree_lock_page_hook(struct page *page)
+{
+        struct inode *inode = page->mapping->host;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        struct extent_buffer *eb;
+        unsigned long len;
+        u64 bytenr = page_offset(page);
+
+        if (page->private == EXTENT_PAGE_PRIVATE)
+                goto out;
+
+        len = page->private >> 2;
+        eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
+        if (!eb)
+                goto out;
+
+        btrfs_tree_lock(eb);
+        spin_lock(&root->fs_info->hash_lock);
+        btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
+        spin_unlock(&root->fs_info->hash_lock);
+        btrfs_tree_unlock(eb);
+        free_extent_buffer(eb);
+out:
+        lock_page(page);
+        return 0;
+}
+
 static struct extent_io_ops btree_extent_io_ops = {
+        .write_cache_pages_lock_hook = btree_lock_page_hook,
         .writepage_io_hook = btree_writepage_io_hook,
         .readpage_end_io_hook = btree_readpage_end_io_hook,
         .submit_bio_hook = btree_submit_bio_hook,