[PATCH] fix up new filp allocators

Some new uses of get_empty_filp() have crept in; switched
to alloc_file() to make sure that pieces of initialization
won't be missing.

We really need to kill get_empty_filp().

[AV] fixed dentry leak on failure exit in anon_inode_getfd()

Cc: Erez Zadok <[e-mail]>
Cc: Trond Myklebust <[e-mail]>
Cc: "J Bruce Fields" <[e-mail]>
Acked-by: Al Viro <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Dave Hansen <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

fs/anon_inodes.c

···
 
 	if (IS_ERR(anon_inode_inode))
 		return -ENODEV;
-	file = get_empty_filp();
-	if (!file)
-		return -ENFILE;
 
 	error = get_unused_fd();
 	if (error < 0)
-		goto err_put_filp;
+		return error;
 	fd = error;
 
 	/*
···
 	dentry->d_flags &= ~DCACHE_UNHASHED;
 	d_instantiate(dentry, anon_inode_inode);
 
-	file->f_path.mnt = mntget(anon_inode_mnt);
-	file->f_path.dentry = dentry;
+	error = -ENFILE;
+	file = alloc_file(anon_inode_mnt, dentry,
+			  FMODE_READ | FMODE_WRITE, fops);
+	if (!file)
+		goto err_dput;
 	file->f_mapping = anon_inode_inode->i_mapping;
 
 	file->f_pos = 0;
 	file->f_flags = O_RDWR;
-	file->f_op = fops;
-	file->f_mode = FMODE_READ | FMODE_WRITE;
 	file->f_version = 0;
 	file->private_data = priv;
 
···
 	*pfile = file;
 	return 0;
 
+err_dput:
+	dput(dentry);
 err_put_unused_fd:
 	put_unused_fd(fd);
-err_put_filp:
-	put_filp(file);
 	return error;
 }
 EXPORT_SYMBOL_GPL(anon_inode_getfd);

fs/file_table.c

···
 /* Find an unused file structure and return a pointer to it.
  * Returns NULL, if there are no more free file structures or
  * we run out of memory.
+ *
+ * Be very careful using this.  You are responsible for
+ * getting write access to any mount that you might assign
+ * to this filp, if it is opened for write.  If this is not
+ * done, you will imbalance int the mount's writer count
+ * and a warning at __fput() time.
  */
 struct file *get_empty_filp(void)
 {

fs/pipe.c

···
 	struct dentry *dentry;
 	struct qstr name = { .name = "" };
 
-	f = get_empty_filp();
-	if (!f)
-		return ERR_PTR(-ENFILE);
 	err = -ENFILE;
 	inode = get_pipe_inode();
 	if (!inode)
-		goto err_file;
+		goto err;
 
 	err = -ENOMEM;
 	dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name);
···
 	 */
 	dentry->d_flags &= ~DCACHE_UNHASHED;
 	d_instantiate(dentry, inode);
-	f->f_path.mnt = mntget(pipe_mnt);
-	f->f_path.dentry = dentry;
+
+	err = -ENFILE;
+	f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipe_fops);
+	if (!f)
+		goto err_dentry;
 	f->f_mapping = inode->i_mapping;
 
 	f->f_flags = O_WRONLY;
-	f->f_op = &write_pipe_fops;
-	f->f_mode = FMODE_WRITE;
 	f->f_version = 0;
 
 	return f;
 
+ err_dentry:
+	dput(dentry);
  err_inode:
 	free_pipe_info(inode);
 	iput(inode);
- err_file:
-	put_filp(f);
+ err:
 	return ERR_PTR(err);
 }