Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull VFS changes from Al Viro:
 "First pile out of several (there _definitely_ will be more).  Stuff in
  this one:

   - unification of d_splice_alias()/d_materialize_unique()

   - iov_iter rewrite

   - killing a bunch of ->f_path.dentry users (and f_dentry macro).

     Getting that completed will make life much simpler for
     unionmount/overlayfs, since then we'll be able to limit the places
     sensitive to file _dentry_ to reasonably few.  Which allows to have
     file_inode(file) pointing to inode in a covered layer, with dentry
     pointing to (negative) dentry in union one.

     Still not complete, but much closer now.

   - crapectomy in lustre (dead code removal, mostly)

   - "let's make seq_printf return nothing" preparations

   - assorted cleanups and fixes

  There _definitely_ will be more piles"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  copy_from_iter_nocache()
  new helper: iov_iter_kvec()
  csum_and_copy_..._iter()
  iov_iter.c: handle ITER_KVEC directly
  iov_iter.c: convert copy_to_iter() to iterate_and_advance
  iov_iter.c: convert copy_from_iter() to iterate_and_advance
  iov_iter.c: get rid of bvec_copy_page_{to,from}_iter()
  iov_iter.c: convert iov_iter_zero() to iterate_and_advance
  iov_iter.c: convert iov_iter_get_pages_alloc() to iterate_all_kinds
  iov_iter.c: convert iov_iter_get_pages() to iterate_all_kinds
  iov_iter.c: convert iov_iter_npages() to iterate_all_kinds
  iov_iter.c: iterate_and_advance
  iov_iter.c: macros for iterating over iov_iter
  kill f_dentry macro
  dcache: fix kmemcheck warning in switch_names
  new helper: audit_file()
  nfsd_vfs_write(): use file_inode()
  ncpfs: use file_inode()
  kill f_dentry uses
  lockd: get rid of ->f_path.dentry->d_sb
  ...

fs/btrfs/inode.c

@@ -5303,7 +5303,7 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 			return ERR_CAST(inode);
 	}
 
-	return d_materialise_unique(dentry, inode);
+	return d_splice_alias(inode, dentry);
 }
 
 unsigned char btrfs_filetype_table[] = {

fs/btrfs/ioctl.c

@@ -5296,7 +5296,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 		ret = btrfs_start_delalloc_roots(root->fs_info, 0, -1);
 		if (ret)
 			return ret;
-		ret = btrfs_sync_fs(file->f_dentry->d_sb, 1);
+		ret = btrfs_sync_fs(file_inode(file)->i_sb, 1);
 		/*
 		 * The transaction thread may want to do more work,
 		 * namely it pokes the cleaner ktread that will start