1 files changed, 10 insertions, 2 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 787b50a16a14..e354c33df082 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1140,7 +1140,7 @@ int btrfs_sync_file(struct file *file, int datasync)
         /*
          * ok we haven't committed the transaction yet, lets do a commit
          */
-        if (file && file->private_data)
+        if (file->private_data)
                 btrfs_ioctl_trans_end(file);
 
         trans = btrfs_start_transaction(root, 0);
@@ -1190,14 +1190,22 @@ static const struct vm_operations_struct btrfs_file_vm_ops = {
 
 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
 {
-        vma->vm_ops = &btrfs_file_vm_ops;
+        struct address_space *mapping = filp->f_mapping;
+
+        if (!mapping->a_ops->readpage)
+                return -ENOEXEC;
+
         file_accessed(filp);
+        vma->vm_ops = &btrfs_file_vm_ops;
+        vma->vm_flags |= VM_CAN_NONLINEAR;
+
         return 0;
 }
 
 const struct file_operations btrfs_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = do_sync_read,
+        .write          = do_sync_write,
         .aio_read       = generic_file_aio_read,
         .splice_read    = generic_file_splice_read,
         .aio_write      = btrfs_file_aio_write,