/* * This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
* Copyright (C) 2006, 2007 University of Szeged, Hungary
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
* Zoltan Sogor
*/
/*
* This file implements directory operations.
*
* All FS operations in this file allocate budget before writing anything to the
* media. If they fail to allocate it, the error is returned. The only
* exceptions are 'ubifs_unlink()' and 'ubifs_rmdir()' which keep working even
* if they unable to allocate the budget, because deletion %-ENOSPC failure is
* not what users are usually ready to get. UBIFS budgeting subsystem has some
* space reserved for these purposes.
*
* All operations in this file write all inodes which they change straight
* away, instead of marking them dirty. For example, 'ubifs_link()' changes
* @i_size of the parent inode and writes the parent inode together with the
* target inode. This was done to simplify file-system recovery which would
* otherwise be very difficult to do. The only exception is rename which marks
* the re-named inode dirty (because its @i_ctime is updated) but does not
* write it, but just marks it as dirty.
*/
#include "ubifs.h"
/**
* inherit_flags - inherit flags of the parent inode.
* @dir: parent inode
* @mode: new inode mode flags
*
* This is a helper function for 'ubifs_new_inode()' which inherits flag of the
* parent directory inode @dir. UBIFS inodes inherit the following flags:
* o %UBIFS_COMPR_FL, which is useful to switch compression on/of on
* sub-directory basis;
* o %UBIFS_SYNC_FL - useful for the same reasons;
* o %UBIFS_DIRSYNC_FL - similar, but relevant only to directories.
*
* This function returns the inherited flags.
*/
static int inherit_flags(const struct inode *dir, umode_t mode)
{
int flags;
const struct ubifs_inode *ui = ubifs_inode(dir);
if (!S_ISDIR(dir->i_mode))
/*
* The parent is not a directory, which means that an extended
* attribute inode is being created. No flags.
*/
return 0;
flags = ui->flags & (UBIFS_COMPR_FL | UBIFS_SYNC_FL | UBIFS_DIRSYNC_FL);
if (!S_ISDIR(mode))
/* The "DIRSYNC" flag only applies to directories */
flags &= ~UBIFS_DIRSYNC_FL;
return flags;
}
/**
* ubifs_new_inode - allocate new UBIFS inode object.
* @c: UBIFS file-system description object
* @dir: parent directory inode
* @mode: inode mode flags
*
* This function finds an unused inode number, allocates new inode and
* initializes it. Returns new inode in case of success and an error code in
* case of failure.
*/
struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
umode_t mode)
{
struct inode *inode;
struct ubifs_inode *ui;
inode = new_inode(c->vfs_sb);
ui = ubifs_inode(inode);
if (!inode)
return ERR_PTR(-ENOMEM);
/*
* Set 'S_NOCMTIME' to prevent VFS form updating [mc]time of inodes and
* marking them dirty in file write path (see 'file_update_time()').
* UBIFS has to fully control "clean <-> dirty" transitions of inodes
* to make budgeting work.
*/
inode->i_flags |= S_NOCMTIME;
inode_init_owner(inode, dir, mode);
inode->i_mtime = inode->i_atime = inode->i_ctime =
ubifs_current_time(inode);
inode->i_mapping->nrpages = 0;
/* Disable readahead */
inode->i_mapping->backing_dev_info = &c->bdi;
switch (mode & S_IFMT) {
case S_IFREG:
inode->i_mapping->a_ops = &ubifs_file_address_operations;
inode->i_op = &ubifs_file_inode_operations;
inode->i_fop = &ubifs_file_operations;
break;
case S_IFDIR:
inode->i_op = &ubifs_dir_inode_operations;
inode->i_fop = &ubifs_dir_operations;
inode->i_size = ui->ui_size = UBIFS_INO_NODE_SZ;
break;
case S_IFLNK:
inode->i_op = &ubifs_symlink_inode_operations;
break;
case S_IFSOCK:
case S_IFIFO:
case S_IFBLK:
case