e2fsck/dirinfo.c - platform/external/e2fsprogs - Git at Google

 /*
  * dirinfo.c --- maintains the directory information table for e2fsck.
  *
  * Copyright (C) 1993 Theodore Ts'o.  This file may be redistributed
  * under the terms of the GNU Public License.
  */

 #undef DIRINFO_DEBUG

 #include "e2fsck.h"
 #include <sys/stat.h>
 #include <fcntl.h>
 #include "uuid/uuid.h"

 #include <ext2fs/tdb.h>

 struct dir_info_db {
 	int		count;
 	int		size;
 	struct dir_info *array;
 	struct dir_info *last_lookup;
 	char		*tdb_fn;
 	TDB_CONTEXT	*tdb;
 };

 struct dir_info_iter {
 	int	i;
 	TDB_DATA	tdb_iter;
 };

 struct dir_info_ent {
 	ext2_ino_t		dotdot;	/* Parent according to '..' */
 	ext2_ino_t		parent; /* Parent according to treewalk */
 };


 static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir);

 static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
 {
 	struct dir_info_db	*db = ctx->dir_info;
 	unsigned int		threshold;
 	errcode_t		retval;
 	char			*tdb_dir, uuid[40];
 	int			fd, enable;

 	profile_get_string(ctx->profile, "scratch_files", "directory", 0, 0,
 			   &tdb_dir);
 	profile_get_uint(ctx->profile, "scratch_files",
 			 "numdirs_threshold", 0, 0, &threshold);
 	profile_get_boolean(ctx->profile, "scratch_files",
 			    "dirinfo", 0, 1, &enable);

 	if (!enable || !tdb_dir || access(tdb_dir, W_OK) ||
 	    (threshold && num_dirs <= threshold))
 		return;

 	retval = ext2fs_get_mem(strlen(tdb_dir) + 64, &db->tdb_fn);
 	if (retval)
 		return;

 	uuid_unparse(ctx->fs->super->s_uuid, uuid);
 	sprintf(db->tdb_fn, "%s/%s-dirinfo-XXXXXX", tdb_dir, uuid);
 	fd = mkstemp(db->tdb_fn);
 	db->tdb = tdb_open(db->tdb_fn, 0, TDB_CLEAR_IF_FIRST,
 			   O_RDWR | O_CREAT | O_TRUNC, 0600);
 	close(fd);
 }

 static void setup_db(e2fsck_t ctx)
 {
 	struct dir_info_db	*db;
 	ext2_ino_t		num_dirs;
 	errcode_t		retval;

 	db = (struct dir_info_db *)
 		e2fsck_allocate_memory(ctx, sizeof(struct dir_info_db),
 				       "directory map db");
 	db->count = db->size = 0;
 	db->array = 0;

 	ctx->dir_info = db;

 	retval = ext2fs_get_num_dirs(ctx->fs, &num_dirs);
 	if (retval)
 		num_dirs = 1024;	/* Guess */

 	setup_tdb(ctx, num_dirs);

 	if (db->tdb) {
 #ifdef DIRINFO_DEBUG
 		printf("Note: using tdb!\n");
 #endif
 		return;
 	}

 	db->size = num_dirs + 10;
 	db->array  = (struct dir_info *)
 		e2fsck_allocate_memory(ctx, db->size
 				       * sizeof (struct dir_info),
 				       "directory map");
 }

 /*
  * This subroutine is called during pass1 to create a directory info
  * entry.  During pass1, the passed-in parent is 0; it will get filled
  * in during pass2.
  */
 void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent)
 {
 	struct dir_info_db 	*db;
 	struct dir_info 	*dir, ent;
 	int			i, j;
 	errcode_t		retval;
 	unsigned long		old_size;

 #ifdef DIRINFO_DEBUG
 	printf("add_dir_info for inode (%lu, %lu)...\n", ino, parent);
 #endif
 	if (!ctx->dir_info)
 		setup_db(ctx);
 	db = ctx->dir_info;

 	if (ctx->dir_info->count >= ctx->dir_info->size) {
 		old_size = ctx->dir_info->size * sizeof(struct dir_info);
 		ctx->dir_info->size += 10;
 		retval = ext2fs_resize_mem(old_size, ctx->dir_info->size *
 					   sizeof(struct dir_info),
 					   &ctx->dir_info->array);
 		if (retval) {
 			ctx->dir_info->size -= 10;
 			return;
 		}
 	}

 	ent.ino = ino;
 	ent.parent = parent;
 	ent.dotdot = parent;

 	if (db->tdb) {
 		e2fsck_put_dir_info(ctx, &ent);
 		return;
 	}

 	/*
 	 * Normally, add_dir_info is called with each inode in
 	 * sequential order; but once in a while (like when pass 3
 	 * needs to recreate the root directory or lost+found
 	 * directory) it is called out of order.  In those cases, we
 	 * need to move the dir_info entries down to make room, since
 	 * the dir_info array needs to be sorted by inode number for
 	 * get_dir_info()'s sake.
 	 */
 	if (ctx->dir_info->count &&
 	    ctx->dir_info->array[ctx->dir_info->count-1].ino >= ino) {
 		for (i = ctx->dir_info->count-1; i > 0; i--)
 			if (ctx->dir_info->array[i-1].ino < ino)
 				break;
 		dir = &ctx->dir_info->array[i];
 		if (dir->ino != ino)
 			for (j = ctx->dir_info->count++; j > i; j--)
 				ctx->dir_info->array[j] = ctx->dir_info->array[j-1];
 	} else
 		dir = &ctx->dir_info->array[ctx->dir_info->count++];

 	dir->ino = ino;
 	dir->dotdot = parent;
 	dir->parent = parent;
 }

 /*
  * get_dir_info() --- given an inode number, try to find the directory
  * information entry for it.
  */
 static struct dir_info *e2fsck_get_dir_info(e2fsck_t ctx, ext2_ino_t ino)
 {
 	struct dir_info_db	*db = ctx->dir_info;
 	int			low, high, mid;
 	struct dir_info_ent	*buf;
 	static struct dir_info	ret_dir_info;

 	if (!db)
 		return 0;

 #ifdef DIRINFO_DEBUG
 	printf("e2fsck_get_dir_info %d...", ino);
 #endif

 	if (db->tdb) {
 		TDB_DATA key, data;

 		key.dptr = (unsigned char *) &ino;
 		key.dsize = sizeof(ext2_ino_t);

 		data = tdb_fetch(db->tdb, key);
 		if (!data.dptr) {
 			if (tdb_error(db->tdb) != TDB_ERR_NOEXIST)
 				printf("fetch failed: %s\n",
 				       tdb_errorstr(db->tdb));
 			return 0;
 		}

 		buf = (struct dir_info_ent *) data.dptr;
 		ret_dir_info.ino = ino;
 		ret_dir_info.dotdot = buf->dotdot;
 		ret_dir_info.parent = buf->parent;
 #ifdef DIRINFO_DEBUG
 		printf("(%d,%d,%d)\n", ino, buf->dotdot, buf->parent);
 #endif
 		free(data.dptr);
 		return &ret_dir_info;
 	}

 	if (db->last_lookup && db->last_lookup->ino == ino)
 		return db->last_lookup;

 	low = 0;
 	high = ctx->dir_info->count-1;
 	if (ino == ctx->dir_info->array[low].ino) {
 #ifdef DIRINFO_DEBUG
 		printf("(%d,%d,%d)\n", ino,
 		       ctx->dir_info->array[low].dotdot,
 		       ctx->dir_info->array[low].parent);
 #endif
 		return &ctx->dir_info->array[low];
 	}
 	if (ino == ctx->dir_info->array[high].ino) {
 #ifdef DIRINFO_DEBUG
 		printf("(%d,%d,%d)\n", ino,
 		       ctx->dir_info->array[high].dotdot,
 		       ctx->dir_info->array[high].parent);
 #endif
 		return &ctx->dir_info->array[high];
 	}

 	while (low < high) {
 		mid = (low+high)/2;
 		if (mid == low || mid == high)
 			break;
 		if (ino == ctx->dir_info->array[mid].ino) {
 #ifdef DIRINFO_DEBUG
 			printf("(%d,%d,%d)\n", ino,
 			       ctx->dir_info->array[mid].dotdot,
 			       ctx->dir_info->array[mid].parent);
 #endif
 			return &ctx->dir_info->array[mid];
 		}
 		if (ino < ctx->dir_info->array[mid].ino)
 			high = mid;
 		else
 			low = mid;
 	}
 	return 0;
 }

 static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir)
 {
 	struct dir_info_db	*db = ctx->dir_info;
 	struct dir_info_ent	buf;
 	TDB_DATA		key, data;

 #ifdef DIRINFO_DEBUG
 	printf("e2fsck_put_dir_info (%d, %d, %d)...", dir->ino, dir->dotdot,
 	       dir->parent);
 #endif

 	if (!db->tdb)
 		return;

 	buf.parent = dir->parent;
 	buf.dotdot = dir->dotdot;

 	key.dptr = (unsigned char *) &dir->ino;
 	key.dsize = sizeof(ext2_ino_t);
 	data.dptr = (unsigned char *) &buf;
 	data.dsize = sizeof(buf);

 	if (tdb_store(db->tdb, key, data, TDB_REPLACE) == -1) {
 		printf("store failed: %s\n", tdb_errorstr(db->tdb));
 	}
 	return;
 }

 /*
  * Free the dir_info structure when it isn't needed any more.
  */
 void e2fsck_free_dir_info(e2fsck_t ctx)
 {
 	if (ctx->dir_info) {
 		if (ctx->dir_info->tdb)
 			tdb_close(ctx->dir_info->tdb);
 		if (ctx->dir_info->tdb_fn) {
 			unlink(ctx->dir_info->tdb_fn);
 			free(ctx->dir_info->tdb_fn);
 		}
 		if (ctx->dir_info->array)
 			ext2fs_free_mem(&ctx->dir_info->array);
 		ctx->dir_info->array = 0;
 		ctx->dir_info->size = 0;
 		ctx->dir_info->count = 0;
 		ext2fs_free_mem(&ctx->dir_info);
 		ctx->dir_info = 0;
 	}
 }

 /*
  * Return the count of number of directories in the dir_info structure
  */
 int e2fsck_get_num_dirinfo(e2fsck_t ctx)
 {
 	return ctx->dir_info ? ctx->dir_info->count : 0;
 }

 extern struct dir_info_iter *e2fsck_dir_info_iter_begin(e2fsck_t ctx)
 {
 	struct dir_info_iter *iter;
 	struct dir_info_db *db = ctx->dir_info;

 	iter = e2fsck_allocate_memory(ctx, sizeof(struct dir_info_iter),
 				      "dir_info iterator");
 	memset(iter, 0, sizeof(iter));

 	if (db->tdb)
 		iter->tdb_iter = tdb_firstkey(db->tdb);

 	return iter;
 }

 extern void e2fsck_dir_info_iter_end(e2fsck_t ctx EXT2FS_ATTR((unused)),
 				     struct dir_info_iter *iter)
 {
 	free(iter->tdb_iter.dptr);
 	ext2fs_free_mem(&iter);
 }

 /*
  * A simple interator function
  */
 struct dir_info *e2fsck_dir_info_iter(e2fsck_t ctx, struct dir_info_iter *iter)
 {
 	TDB_DATA data, key;
 	struct dir_info_db *db = ctx->dir_info;
 	struct dir_info_ent *buf;
 	static struct dir_info ret_dir_info;

 	if (!ctx->dir_info || !iter)
 		return 0;

 	if (db->tdb) {
 		if (iter->tdb_iter.dptr == 0)
 			return 0;
 		key = iter->tdb_iter;
 		data = tdb_fetch(db->tdb, key);
 		if (!data.dptr) {
 			printf("iter fetch failed: %s\n",
 			       tdb_errorstr(db->tdb));
 			return 0;
 		}
 		buf = (struct dir_info_ent *) data.dptr;
 		ret_dir_info.ino = *((ext2_ino_t *) iter->tdb_iter.dptr);
 		ret_dir_info.dotdot = buf->dotdot;
 		ret_dir_info.parent = buf->parent;
 		iter->tdb_iter = tdb_nextkey(db->tdb, key);
 		free(key.dptr);
 		free(data.dptr);
 		return &ret_dir_info;
 	}

 	if (iter->i >= ctx->dir_info->count)
 		return 0;

 #ifdef DIRINFO_DEBUG
 	printf("iter(%d, %d, %d)...", ctx->dir_info->array[iter->i].ino,
 	       ctx->dir_info->array[iter->i].dotdot,
 	       ctx->dir_info->array[iter->i].parent);
 #endif
 	ctx->dir_info->last_lookup = ctx->dir_info->array + iter->i++;
 	return(ctx->dir_info->last_lookup);
 }

 /*
  * This function only sets the parent pointer, and requires that
  * dirinfo structure has already been created.
  */
 int e2fsck_dir_info_set_parent(e2fsck_t ctx, ext2_ino_t ino,
 			       ext2_ino_t parent)
 {
 	struct dir_info *p;

 	p = e2fsck_get_dir_info(ctx, ino);
 	if (!p)
 		return 1;
 	p->parent = parent;
 	e2fsck_put_dir_info(ctx, p);
 	return 0;
 }

 /*
  * This function only sets the dot dot pointer, and requires that
  * dirinfo structure has already been created.
  */
 int e2fsck_dir_info_set_dotdot(e2fsck_t ctx, ext2_ino_t ino,
 			       ext2_ino_t dotdot)
 {
 	struct dir_info *p;

 	p = e2fsck_get_dir_info(ctx, ino);
 	if (!p)
 		return 1;
 	p->dotdot = dotdot;
 	e2fsck_put_dir_info(ctx, p);
 	return 0;
 }

 /*
  * This function only sets the parent pointer, and requires that
  * dirinfo structure has already been created.
  */
 int e2fsck_dir_info_get_parent(e2fsck_t ctx, ext2_ino_t ino,
 			       ext2_ino_t *parent)
 {
 	struct dir_info *p;

 	p = e2fsck_get_dir_info(ctx, ino);
 	if (!p)
 		return 1;
 	*parent = p->parent;
 	return 0;
 }

 /*
  * This function only sets the dot dot pointer, and requires that
  * dirinfo structure has already been created.
  */
 int e2fsck_dir_info_get_dotdot(e2fsck_t ctx, ext2_ino_t ino,
 			       ext2_ino_t *dotdot)
 {
 	struct dir_info *p;

 	p = e2fsck_get_dir_info(ctx, ino);
 	if (!p)
 		return 1;
 	*dotdot = p->dotdot;
 	return 0;
 }
	/*
	* dirinfo.c --- maintains the directory information table for e2fsck.
	*
	* Copyright (C) 1993 Theodore Ts'o. This file may be redistributed
	* under the terms of the GNU Public License.
	*/

	#undef DIRINFO_DEBUG

	#include "e2fsck.h"
	#include <sys/stat.h>
	#include <fcntl.h>
	#include "uuid/uuid.h"

	#include <ext2fs/tdb.h>

	struct dir_info_db {
	int count;
	int size;
	struct dir_info *array;
	struct dir_info *last_lookup;
	char *tdb_fn;
	TDB_CONTEXT *tdb;
	};

	struct dir_info_iter {
	int i;
	TDB_DATA tdb_iter;
	};

	struct dir_info_ent {
	ext2_ino_t dotdot; /* Parent according to '..' */
	ext2_ino_t parent; /* Parent according to treewalk */
	};


	static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir);

	static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
	{
	struct dir_info_db *db = ctx->dir_info;
	unsigned int threshold;
	errcode_t retval;
	char *tdb_dir, uuid[40];
	int fd, enable;

	profile_get_string(ctx->profile, "scratch_files", "directory", 0, 0,
	&tdb_dir);
	profile_get_uint(ctx->profile, "scratch_files",
	"numdirs_threshold", 0, 0, &threshold);
	profile_get_boolean(ctx->profile, "scratch_files",
	"dirinfo", 0, 1, &enable);

	if (!enable \|\| !tdb_dir \|\| access(tdb_dir, W_OK) \|\|
	(threshold && num_dirs <= threshold))
	return;

	retval = ext2fs_get_mem(strlen(tdb_dir) + 64, &db->tdb_fn);
	if (retval)
	return;

	uuid_unparse(ctx->fs->super->s_uuid, uuid);
	sprintf(db->tdb_fn, "%s/%s-dirinfo-XXXXXX", tdb_dir, uuid);
	fd = mkstemp(db->tdb_fn);
	db->tdb = tdb_open(db->tdb_fn, 0, TDB_CLEAR_IF_FIRST,
	O_RDWR \| O_CREAT \| O_TRUNC, 0600);
	close(fd);
	}

	static void setup_db(e2fsck_t ctx)
	{
	struct dir_info_db *db;
	ext2_ino_t num_dirs;
	errcode_t retval;

	db = (struct dir_info_db *)
	e2fsck_allocate_memory(ctx, sizeof(struct dir_info_db),
	"directory map db");
	db->count = db->size = 0;
	db->array = 0;

	ctx->dir_info = db;

	retval = ext2fs_get_num_dirs(ctx->fs, &num_dirs);
	if (retval)
	num_dirs = 1024; /* Guess */

	setup_tdb(ctx, num_dirs);

	if (db->tdb) {
	#ifdef DIRINFO_DEBUG
	printf("Note: using tdb!\n");
	#endif
	return;
	}

	db->size = num_dirs + 10;
	db->array = (struct dir_info *)
	e2fsck_allocate_memory(ctx, db->size
	* sizeof (struct dir_info),
	"directory map");
	}

	/*
	* This subroutine is called during pass1 to create a directory info
	* entry. During pass1, the passed-in parent is 0; it will get filled
	* in during pass2.
	*/
	void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent)
	{
	struct dir_info_db *db;
	struct dir_info *dir, ent;
	int i, j;
	errcode_t retval;
	unsigned long old_size;

	#ifdef DIRINFO_DEBUG
	printf("add_dir_info for inode (%lu, %lu)...\n", ino, parent);
	#endif
	if (!ctx->dir_info)
	setup_db(ctx);
	db = ctx->dir_info;

	if (ctx->dir_info->count >= ctx->dir_info->size) {
	old_size = ctx->dir_info->size * sizeof(struct dir_info);
	ctx->dir_info->size += 10;
	retval = ext2fs_resize_mem(old_size, ctx->dir_info->size *
	sizeof(struct dir_info),
	&ctx->dir_info->array);
	if (retval) {
	ctx->dir_info->size -= 10;
	return;
	}
	}

	ent.ino = ino;
	ent.parent = parent;
	ent.dotdot = parent;

	if (db->tdb) {
	e2fsck_put_dir_info(ctx, &ent);
	return;
	}

	/*
	* Normally, add_dir_info is called with each inode in
	* sequential order; but once in a while (like when pass 3
	* needs to recreate the root directory or lost+found
	* directory) it is called out of order. In those cases, we
	* need to move the dir_info entries down to make room, since
	* the dir_info array needs to be sorted by inode number for
	* get_dir_info()'s sake.
	*/
	if (ctx->dir_info->count &&
	ctx->dir_info->array[ctx->dir_info->count-1].ino >= ino) {
	for (i = ctx->dir_info->count-1; i > 0; i--)
	if (ctx->dir_info->array[i-1].ino < ino)
	break;
	dir = &ctx->dir_info->array[i];
	if (dir->ino != ino)
	for (j = ctx->dir_info->count++; j > i; j--)
	ctx->dir_info->array[j] = ctx->dir_info->array[j-1];
	} else
	dir = &ctx->dir_info->array[ctx->dir_info->count++];

	dir->ino = ino;
	dir->dotdot = parent;
	dir->parent = parent;
	}

	/*
	* get_dir_info() --- given an inode number, try to find the directory
	* information entry for it.
	*/
	static struct dir_info *e2fsck_get_dir_info(e2fsck_t ctx, ext2_ino_t ino)
	{
	struct dir_info_db *db = ctx->dir_info;
	int low, high, mid;
	struct dir_info_ent *buf;
	static struct dir_info ret_dir_info;

	if (!db)
	return 0;

	#ifdef DIRINFO_DEBUG
	printf("e2fsck_get_dir_info %d...", ino);
	#endif

	if (db->tdb) {
	TDB_DATA key, data;

	key.dptr = (unsigned char *) &ino;
	key.dsize = sizeof(ext2_ino_t);

	data = tdb_fetch(db->tdb, key);
	if (!data.dptr) {
	if (tdb_error(db->tdb) != TDB_ERR_NOEXIST)
	printf("fetch failed: %s\n",
	tdb_errorstr(db->tdb));
	return 0;
	}

	buf = (struct dir_info_ent *) data.dptr;
	ret_dir_info.ino = ino;
	ret_dir_info.dotdot = buf->dotdot;
	ret_dir_info.parent = buf->parent;
	#ifdef DIRINFO_DEBUG
	printf("(%d,%d,%d)\n", ino, buf->dotdot, buf->parent);
	#endif
	free(data.dptr);
	return &ret_dir_info;
	}

	if (db->last_lookup && db->last_lookup->ino == ino)
	return db->last_lookup;

	low = 0;
	high = ctx->dir_info->count-1;
	if (ino == ctx->dir_info->array[low].ino) {
	#ifdef DIRINFO_DEBUG
	printf("(%d,%d,%d)\n", ino,
	ctx->dir_info->array[low].dotdot,
	ctx->dir_info->array[low].parent);
	#endif
	return &ctx->dir_info->array[low];
	}
	if (ino == ctx->dir_info->array[high].ino) {
	#ifdef DIRINFO_DEBUG
	printf("(%d,%d,%d)\n", ino,
	ctx->dir_info->array[high].dotdot,
	ctx->dir_info->array[high].parent);
	#endif
	return &ctx->dir_info->array[high];
	}

	while (low < high) {
	mid = (low+high)/2;
	if (mid == low \|\| mid == high)
	break;
	if (ino == ctx->dir_info->array[mid].ino) {
	#ifdef DIRINFO_DEBUG
	printf("(%d,%d,%d)\n", ino,
	ctx->dir_info->array[mid].dotdot,
	ctx->dir_info->array[mid].parent);
	#endif
	return &ctx->dir_info->array[mid];
	}
	if (ino < ctx->dir_info->array[mid].ino)
	high = mid;
	else
	low = mid;
	}
	return 0;
	}

	static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir)
	{
	struct dir_info_db *db = ctx->dir_info;
	struct dir_info_ent buf;
	TDB_DATA key, data;

	#ifdef DIRINFO_DEBUG
	printf("e2fsck_put_dir_info (%d, %d, %d)...", dir->ino, dir->dotdot,
	dir->parent);
	#endif

	if (!db->tdb)
	return;

	buf.parent = dir->parent;
	buf.dotdot = dir->dotdot;

	key.dptr = (unsigned char *) &dir->ino;
	key.dsize = sizeof(ext2_ino_t);
	data.dptr = (unsigned char *) &buf;
	data.dsize = sizeof(buf);

	if (tdb_store(db->tdb, key, data, TDB_REPLACE) == -1) {
	printf("store failed: %s\n", tdb_errorstr(db->tdb));
	}
	return;
	}

	/*
	* Free the dir_info structure when it isn't needed any more.
	*/
	void e2fsck_free_dir_info(e2fsck_t ctx)
	{
	if (ctx->dir_info) {
	if (ctx->dir_info->tdb)
	tdb_close(ctx->dir_info->tdb);
	if (ctx->dir_info->tdb_fn) {
	unlink(ctx->dir_info->tdb_fn);
	free(ctx->dir_info->tdb_fn);
	}
	if (ctx->dir_info->array)
	ext2fs_free_mem(&ctx->dir_info->array);
	ctx->dir_info->array = 0;
	ctx->dir_info->size = 0;
	ctx->dir_info->count = 0;
	ext2fs_free_mem(&ctx->dir_info);
	ctx->dir_info = 0;
	}
	}

	/*
	* Return the count of number of directories in the dir_info structure
	*/
	int e2fsck_get_num_dirinfo(e2fsck_t ctx)
	{
	return ctx->dir_info ? ctx->dir_info->count : 0;
	}

	extern struct dir_info_iter *e2fsck_dir_info_iter_begin(e2fsck_t ctx)
	{
	struct dir_info_iter *iter;
	struct dir_info_db *db = ctx->dir_info;

	iter = e2fsck_allocate_memory(ctx, sizeof(struct dir_info_iter),
	"dir_info iterator");
	memset(iter, 0, sizeof(iter));

	if (db->tdb)
	iter->tdb_iter = tdb_firstkey(db->tdb);

	return iter;
	}

	extern void e2fsck_dir_info_iter_end(e2fsck_t ctx EXT2FS_ATTR((unused)),
	struct dir_info_iter *iter)
	{
	free(iter->tdb_iter.dptr);
	ext2fs_free_mem(&iter);
	}

	/*
	* A simple interator function
	*/
	struct dir_info e2fsck_dir_info_iter(e2fsck_t ctx, struct dir_info_iter iter)
	{
	TDB_DATA data, key;
	struct dir_info_db *db = ctx->dir_info;
	struct dir_info_ent *buf;
	static struct dir_info ret_dir_info;

	if (!ctx->dir_info \|\| !iter)
	return 0;

	if (db->tdb) {
	if (iter->tdb_iter.dptr == 0)
	return 0;
	key = iter->tdb_iter;
	data = tdb_fetch(db->tdb, key);
	if (!data.dptr) {
	printf("iter fetch failed: %s\n",
	tdb_errorstr(db->tdb));
	return 0;
	}
	buf = (struct dir_info_ent *) data.dptr;
	ret_dir_info.ino = ((ext2_ino_t ) iter->tdb_iter.dptr);
	ret_dir_info.dotdot = buf->dotdot;
	ret_dir_info.parent = buf->parent;
	iter->tdb_iter = tdb_nextkey(db->tdb, key);
	free(key.dptr);
	free(data.dptr);
	return &ret_dir_info;
	}

	if (iter->i >= ctx->dir_info->count)
	return 0;

	#ifdef DIRINFO_DEBUG
	printf("iter(%d, %d, %d)...", ctx->dir_info->array[iter->i].ino,
	ctx->dir_info->array[iter->i].dotdot,
	ctx->dir_info->array[iter->i].parent);
	#endif
	ctx->dir_info->last_lookup = ctx->dir_info->array + iter->i++;
	return(ctx->dir_info->last_lookup);
	}

	/*
	* This function only sets the parent pointer, and requires that
	* dirinfo structure has already been created.
	*/
	int e2fsck_dir_info_set_parent(e2fsck_t ctx, ext2_ino_t ino,
	ext2_ino_t parent)
	{
	struct dir_info *p;

	p = e2fsck_get_dir_info(ctx, ino);
	if (!p)
	return 1;
	p->parent = parent;
	e2fsck_put_dir_info(ctx, p);
	return 0;
	}

	/*
	* This function only sets the dot dot pointer, and requires that
	* dirinfo structure has already been created.
	*/
	int e2fsck_dir_info_set_dotdot(e2fsck_t ctx, ext2_ino_t ino,
	ext2_ino_t dotdot)
	{
	struct dir_info *p;

	p = e2fsck_get_dir_info(ctx, ino);
	if (!p)
	return 1;
	p->dotdot = dotdot;
	e2fsck_put_dir_info(ctx, p);
	return 0;
	}

	/*
	* This function only sets the parent pointer, and requires that
	* dirinfo structure has already been created.
	*/
	int e2fsck_dir_info_get_parent(e2fsck_t ctx, ext2_ino_t ino,
	ext2_ino_t *parent)
	{
	struct dir_info *p;

	p = e2fsck_get_dir_info(ctx, ino);
	if (!p)
	return 1;
	*parent = p->parent;
	return 0;
	}

	/*
	* This function only sets the dot dot pointer, and requires that
	* dirinfo structure has already been created.
	*/
	int e2fsck_dir_info_get_dotdot(e2fsck_t ctx, ext2_ino_t ino,
	ext2_ino_t *dotdot)
	{
	struct dir_info *p;

	p = e2fsck_get_dir_info(ctx, ino);
	if (!p)
	return 1;
	*dotdot = p->dotdot;
	return 0;
	}