Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: The file argument for fsync() is never null
  Btrfs: handle ERR_PTR from posix_acl_from_xattr()
  Btrfs: avoid BUG when dropping root and reference in same transaction
  Btrfs: prohibit a operation of changing acl's mask when noacl mount option used
  Btrfs: should add a permission check for setfacl
  Btrfs: btrfs_lookup_dir_item() can return ERR_PTR
  Btrfs: btrfs_read_fs_root_no_name() returns ERR_PTRs
  Btrfs: unwind after btrfs_start_transaction() errors
  Btrfs: btrfs_iget() returns ERR_PTR
  Btrfs: handle kzalloc() failure in open_ctree()
  Btrfs: handle error returns from btrfs_lookup_dir_item()
  Btrfs: Fix BUG_ON for fs converted from extN
  Btrfs: Fix null dereference in relocation.c
  Btrfs: fix remap_file_pages error
  Btrfs: uninitialized data is check_path_shared()
  Btrfs: fix fallocate regression
  Btrfs: fix loop device on top of btrfs

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,