path: root/fs/afs/dir.c

/* dir.c: AFS filesystem directory handling
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include "internal.h"

static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
				 unsigned int flags);
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, struct dir_context *ctx);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static void afs_d_release(struct dentry *dentry);
static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
				  loff_t fpos, u64 ino, unsigned dtype);
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
		      bool excl);
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static int afs_rmdir(struct inode *dir, struct dentry *dentry);
static int afs_unlink(struct inode *dir, struct dentry *dentry);
static int afs_link(struct dentry *from, struct inode *dir,
		    struct dentry *dentry);
static int afs_symlink(struct inode *dir, struct dentry *dentry,
		       const char *content);
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
		      struct inode *new_dir, struct dentry *new_dentry);

const struct file_operations afs_dir_file_operations = {
	.open		= afs_dir_open,
	.release	= afs_release,
	.iterate	= afs_readdir,
	.lock		= afs_lock,
	.llseek		= generic_file_llseek,
};

const struct inode_operations afs_dir_inode_operations = {
	.create		= afs_create,
	.lookup		= afs_lookup,
	.link		= afs_link,
	.unlink		= afs_unlink,
	.symlink	= afs_symlink,
	.mkdir		= afs_mkdir,
	.rmdir		= afs_rmdir,
	.rename		= afs_rename,
	.permission	= afs_permission,
	.getattr	= afs_getattr,
	.setattr	= afs_setattr,
};

const struct dentry_operations afs_fs_dentry_operations = {
	.d_revalidate	= afs_d_revalidate,
	.d_delete	= afs_d_delete,
	.d_release	= afs_d_release,
	.d_automount	= afs_d_automount,
};

#define AFS_DIR_HASHTBL_SIZE	128
#define AFS_DIR_DIRENT_SIZE	32
#define AFS_DIRENT_PER_BLOCK	64

union afs_dirent {
	struct {
		uint8_t		valid;
		uint8_t		unused[1];
		__be16		hash_next;
		__be32		vnode;
		__be32		unique;
		uint8_t		name[16];
		uint8_t		overflow[4];	/* if any char of the name (inc
						 * NUL) reaches here, consume
						 * the next dirent too */
	} u;
	uint8_t	extended_name[32];
};

/* AFS directory page header (one at the beginning of every 2048-byte chunk) */
struct afs_dir_pagehdr {
	__be16		npages;
	__be16		magic;
#define AFS_DIR_MAGIC htons(1234)
	uint8_t		nentries;
	uint8_t		bitmap[8];
	uint8_t		pad[19];
};

/* directory block layout */
union afs_dir_block {

	struct afs_dir_pagehdr pagehdr;

	struct {
		struct afs_dir_pagehdr	pagehdr;
		uint8_t			alloc_ctrs[128];
		/* dir hash table */
		uint16_t		hashtable[AFS_DIR_HASHTBL_SIZE];
	} hdr;

	union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
};

/* layout on a linux VM page */
struct afs_dir_page {
	union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
};

struct afs_lookup_cookie {
	struct dir_context ctx;
	struct afs_fid	fid;
	struct qstr name;
	int		found;
};

/*
 * check that a directory page is valid
 */
static inline void afs_dir_check_page(struct inode *dir, struct page *page)
{
	struct afs_dir_page *dbuf;
	loff_t latter;
	int tmp, qty;

#if 0
	/* check the page count */
	qty = desc.size / sizeof(dbuf->blocks[0]);
	if (qty == 0)
		goto error;

	if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
		printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
		       __func__, dir->i_ino, qty,
		       ntohs(dbuf->blocks[0].pagehdr.npages));
		goto error;
	}
#endif

	/* determine how many magic numbers there should be in this page */
	latter = dir->i_size - page_offset(page);
	if (latter >= PAGE_SIZE)
		qty = PAGE_SIZE;
	else
		qty = latter;
	qty /= sizeof(union afs_dir_block);

	/* check them */
	dbuf = page_address(