1 files changed, 8 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 08760ff9bab7..40b4a8ec17fe 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1180,19 +1180,26 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
                 goto out;
 
         ret = -ENOMEM;
+again:
         page = grab_cache_page(mapping, index);
         if (!page)
                 goto out;
         if (!PageUptodate(page)) {
                 ret = btrfs_readpage(NULL, page);
                 lock_page(page);
+                if (page->mapping != mapping) {
+                        unlock_page(page);
+                        page_cache_release(page);
+                        goto again;
+                }
                 if (!PageUptodate(page)) {
                         ret = -EIO;
                         goto out;
                 }
         }
-        page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 
+        page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+        wait_on_page_writeback(page);
         ret = btrfs_cow_one_page(inode, page, offset);
 
         unlock_page(page);