Btrfs: fix btrfs page_mkwrite to return locked page

This closes a whole where the page may be written before
the page_mkwrite caller has a chance to dirty it

(thanks to Nick Piggin)

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 233fe6f26120c61a7c2a4da5692f3fc7a8ede943..c846482e79850ff2ba3a7eb97bfb23932fa44782 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4552,11 +4552,14 @@ again:
        }
        ClearPageChecked(page);
        set_page_dirty(page);
+       SetPageUptodate(page);
 
        BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
 out_unlock:
+       if (!ret)
+               return VM_FAULT_LOCKED;
        unlock_page(page);
 out:
        return ret;