path: root/fs/jffs2/dir.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include "jffs2_fs_i.h"
#include "jffs2_fs_sb.h"
#include <linux/time.h>
#include "nodelist.h"

static int jffs2_readdir (struct file *, struct dir_context *);

static int jffs2_create (struct inode *,struct dentry *,umode_t,
			 bool);
static struct dentry *jffs2_lookup (struct inode *,struct dentry *,
				    unsigned int);
static int jffs2_link (struct dentry *,struct inode *,struct dentry *);
static int jffs2_unlink (struct inode *,struct dentry *);
static int jffs2_symlink (struct inode *,struct dentry *,const char *);
static int jffs2_mkdir (struct inode *,struct dentry *,umode_t);
static int jffs2_rmdir (struct inode *,struct dentry *);
static int jffs2_mknod (struct inode *,struct dentry *,umode_t,dev_t);
static int jffs2_rename (struct inode *, struct dentry *,
			 struct inode *, struct dentry *);

const struct file_operations jffs2_dir_operations =
{
	.read =		generic_read_dir,
	.iterate_shared=jffs2_readdir,
	.unlocked_ioctl=jffs2_ioctl,
	.fsync =	jffs2_fsync,
	.llseek =	generic_file_llseek,
};


const struct inode_operations jffs2_dir_inode_operations =
{
	.create =	jffs2_create,
	.lookup =	jffs2_lookup,
	.link =		jffs2_link,
	.unlink =	jffs2_unlink,
	.symlink =	jffs2_symlink,
	.mkdir =	jffs2_mkdir,
	.rmdir =	jffs2_rmdir,
	.mknod =	jffs2_mknod,
	.rename =	jffs2_rename,
	.get_acl =	jffs2_get_acl,
	.set_acl =	jffs2_set_acl,
	.setattr =	jffs2_setattr,
	.setxattr =	jffs2_setxattr,
	.getxattr =	jffs2_getxattr,
	.listxattr =	jffs2_listxattr,
	.removexattr =	jffs2_removexattr
};

/***********************************************************************/


/* We keep the dirent list sorted in increasing order of name hash,
   and we use the same hash function as the dentries. Makes this
   nice and simple
*/
static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
				   unsigned int flags)
{
	struct jffs2_inode_info *dir_f;
	struct jffs2_full_dirent *fd = NULL, *fd_list;
	uint32_t ino = 0;
	struct inode *inode = NULL;
	unsigned int nhash;

	jffs2_dbg(1, "jffs2_lookup()\n");

	if (target->d_name.len > JFFS2_MAX_NAME_LEN)
		return ERR_PTR(-ENAMETOOLONG);

	dir_f = JFFS2_INODE_INFO(dir_i);

	/* The 'nhash' on the fd_list is not the same as the dentry hash */
	nhash = full_name_hash(NULL, target->d_name.name, target->d_name.len);

	mutex_lock(&dir_f->sem);

	/* NB: The 2.2 backport will need to explicitly check for '.' and '..' here */
	for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= nhash; fd_list = fd_list->next) {
		if (fd_list->nhash == nhash &&
		    (!fd || fd_list->version > fd->version) &&
		    strlen(fd_list->name) == target->d_name.len &&
		    !strncmp(fd_list->name, target->d_name.name, target->d_name.len)) {
			fd = fd_list;
		}
	}
	if (fd)
		ino = fd->ino;
	mutex_unlock(&dir_f->sem);
	if (ino) {
		inode = jffs2_iget(dir_i->i_sb, ino);
		if (IS_ERR(inode))
			pr_warn("iget() failed for ino #%u\n", ino);
	}

	return d_splice_alias(inode, target);
}

/***********************************************************************/


static int jffs2_readdir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	struct jffs2_full_dirent *fd;
	unsigned long curofs = 1;

	jffs2_dbg(1, "jffs2_readdir() for dir_i #%lu\n", inode->i_ino);

	if (!dir_emit_dots(file, ctx))
		return 0;

	mutex_lock(&f->sem);
	for (fd = f->dents; fd; fd = fd->next) {
		curofs++;
		/* First loop: curofs = 2; pos = 2 */
		if (curofs < ctx->pos) {
			jffs2_dbg(2, "Skipping dirent: \"%s\", ino #%u, type %d, because curofs %ld < offset %ld\n",
				  fd->name, fd->ino, fd->