lib/ext2fs/alloc.c - nest-hello/e2fsprogs - Git at Google

 /*
  * alloc.c --- allocate new inodes, blocks for ext2fs
  *
  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
  *
  * %Begin-Header%
  * This file may be redistributed under the terms of the GNU Library
  * General Public License, version 2.
  * %End-Header%
  */

 #include "config.h"
 #include <stdio.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 #include <time.h>
 #include <string.h>
 #if HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
 #if HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif

 #include "ext2_fs.h"
 #include "ext2fs.h"

 /*
  * Clear the uninit block bitmap flag if necessary
  */
 static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
 {
 	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
 	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
 		return;

 	/* uninit block bitmaps are now initialized in read_bitmaps() */

 	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 	ext2fs_group_desc_csum_set(fs, group);
 	ext2fs_mark_super_dirty(fs);
 	ext2fs_mark_bb_dirty(fs);
 }

 /*
  * Check for uninit inode bitmaps and deal with them appropriately
  */
 static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
 			  dgrp_t group)
 {
 	ext2_ino_t	i, ino;

 	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
 					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
 	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
 		return;

 	ino = (group * fs->super->s_inodes_per_group) + 1;
 	for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
 		ext2fs_fast_unmark_inode_bitmap2(map, ino);

 	ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
 	/* Mimics what the kernel does */
 	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 	ext2fs_group_desc_csum_set(fs, group);
 	ext2fs_mark_ib_dirty(fs);
 	ext2fs_mark_super_dirty(fs);
 }

 /*
  * Right now, just search forward from the parent directory's block
  * group to find the next free inode.
  *
  * Should have a special policy for directories.
  */
 errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
 			   int mode EXT2FS_ATTR((unused)),
 			   ext2fs_inode_bitmap map, ext2_ino_t *ret)
 {
 	ext2_ino_t	start_inode = 0;
 	ext2_ino_t	i, ino_in_group, upto, first_zero;
 	errcode_t	retval;
 	dgrp_t		group;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (!map)
 		map = fs->inode_map;
 	if (!map)
 		return EXT2_ET_NO_INODE_BITMAP;

 	if (dir > 0) {
 		group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
 		start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
 	}
 	if (start_inode < EXT2_FIRST_INODE(fs->super))
 		start_inode = EXT2_FIRST_INODE(fs->super);
 	if (start_inode > fs->super->s_inodes_count)
 		return EXT2_ET_INODE_ALLOC_FAIL;
 	i = start_inode;
 	do {
 		ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
 		group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);

 		check_inode_uninit(fs, map, group);
 		upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
 		if (i < start_inode && upto >= start_inode)
 			upto = start_inode - 1;
 		if (upto > fs->super->s_inodes_count)
 			upto = fs->super->s_inodes_count;

 		retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
 							      &first_zero);
 		if (retval == 0) {
 			i = first_zero;
 			break;
 		}
 		if (retval != ENOENT)
 			return EXT2_ET_INODE_ALLOC_FAIL;
 		i = upto + 1;
 		if (i > fs->super->s_inodes_count)
 			i = EXT2_FIRST_INODE(fs->super);
 	} while (i != start_inode);

 	if (ext2fs_test_inode_bitmap2(map, i))
 		return EXT2_ET_INODE_ALLOC_FAIL;
 	*ret = i;
 	return 0;
 }

 /*
  * Stupid algorithm --- we now just search forward starting from the
  * goal.  Should put in a smarter one someday....
  */
 errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
 			   ext2fs_block_bitmap map, blk64_t *ret)
 {
 	errcode_t retval;
 	blk64_t	b = 0;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (!map)
 		map = fs->block_map;
 	if (!map)
 		return EXT2_ET_NO_BLOCK_BITMAP;
 	if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
 		goal = fs->super->s_first_data_block;
 	goal &= ~EXT2FS_CLUSTER_MASK(fs);

 	retval = ext2fs_find_first_zero_block_bitmap2(map,
 			goal, ext2fs_blocks_count(fs->super) - 1, &b);
 	if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
 		retval = ext2fs_find_first_zero_block_bitmap2(map,
 			fs->super->s_first_data_block, goal - 1, &b);
 	if (retval == ENOENT)
 		return EXT2_ET_BLOCK_ALLOC_FAIL;
 	if (retval)
 		return retval;

 	clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
 	*ret = b;
 	return 0;
 }

 errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
 			   ext2fs_block_bitmap map, blk_t *ret)
 {
 	errcode_t retval;
 	blk64_t val;
 	retval = ext2fs_new_block2(fs, goal, map, &val);
 	if (!retval)
 		*ret = (blk_t) val;
 	return retval;
 }

 /*
  * This function zeros out the allocated block, and updates all of the
  * appropriate filesystem records.
  */
 errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
 			     char *block_buf, blk64_t *ret)
 {
 	errcode_t	retval;
 	blk64_t		block;
 	char		*buf = 0;

 	if (!block_buf) {
 		retval = ext2fs_get_mem(fs->blocksize, &buf);
 		if (retval)
 			return retval;
 		block_buf = buf;
 	}
 	memset(block_buf, 0, fs->blocksize);

 	if (fs->get_alloc_block) {
 		retval = (fs->get_alloc_block)(fs, goal, &block);
 		if (retval)
 			goto fail;
 	} else {
 		if (!fs->block_map) {
 			retval = ext2fs_read_block_bitmap(fs);
 			if (retval)
 				goto fail;
 		}

 		retval = ext2fs_new_block2(fs, goal, 0, &block);
 		if (retval)
 			goto fail;
 	}

 	retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
 	if (retval)
 		goto fail;

 	ext2fs_block_alloc_stats2(fs, block, +1);
 	*ret = block;

 fail:
 	if (buf)
 		ext2fs_free_mem(&buf);
 	return retval;
 }

 errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
 			     char *block_buf, blk_t *ret)
 {
 	errcode_t retval;
 	blk64_t	val;
 	retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
 	if (!retval)
 		*ret = (blk_t) val;
 	return retval;
 }

 errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
 				 int num, ext2fs_block_bitmap map, blk64_t *ret)
 {
 	blk64_t	b = start;
 	int	c_ratio;

 	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

 	if (!map)
 		map = fs->block_map;
 	if (!map)
 		return EXT2_ET_NO_BLOCK_BITMAP;
 	if (!b)
 		b = fs->super->s_first_data_block;
 	if (!finish)
 		finish = start;
 	if (!num)
 		num = 1;
 	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
 	b &= ~(c_ratio - 1);
 	finish &= ~(c_ratio -1);
 	do {
 		if (b + num - 1 >= ext2fs_blocks_count(fs->super)) {
 			if (finish > start)
 				return EXT2_ET_BLOCK_ALLOC_FAIL;
 			b = fs->super->s_first_data_block;
 		}
 		if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
 			*ret = b;
 			return 0;
 		}
 		b += c_ratio;
 	} while (b != finish);
 	return EXT2_ET_BLOCK_ALLOC_FAIL;
 }

 errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
 				 int num, ext2fs_block_bitmap map, blk_t *ret)
 {
 	errcode_t retval;
 	blk64_t val;
 	retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
 	if(!retval)
 		*ret = (blk_t) val;
 	return retval;
 }

 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 				     errcode_t (*func)(ext2_filsys fs,
 						       blk64_t goal,
 						       blk64_t *ret),
 				     errcode_t (**old)(ext2_filsys fs,
 						       blk64_t goal,
 						       blk64_t *ret))
 {
 	if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
 		return;

 	if (old)
 		*old = fs->get_alloc_block;

 	fs->get_alloc_block = func;
 }
	/*
	* alloc.c --- allocate new inodes, blocks for ext2fs
	*
	* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
	*
	* %Begin-Header%
	* This file may be redistributed under the terms of the GNU Library
	* General Public License, version 2.
	* %End-Header%
	*/

	#include "config.h"
	#include <stdio.h>
	#if HAVE_UNISTD_H
	#include <unistd.h>
	#endif
	#include <time.h>
	#include <string.h>
	#if HAVE_SYS_STAT_H
	#include <sys/stat.h>
	#endif
	#if HAVE_SYS_TYPES_H
	#include <sys/types.h>
	#endif

	#include "ext2_fs.h"
	#include "ext2fs.h"

	/*
	* Clear the uninit block bitmap flag if necessary
	*/
	static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
	{
	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
	EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) \|\|
	!(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
	return;

	/* uninit block bitmaps are now initialized in read_bitmaps() */

	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
	ext2fs_group_desc_csum_set(fs, group);
	ext2fs_mark_super_dirty(fs);
	ext2fs_mark_bb_dirty(fs);
	}

	/*
	* Check for uninit inode bitmaps and deal with them appropriately
	*/
	static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
	dgrp_t group)
	{
	ext2_ino_t i, ino;

	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
	EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) \|\|
	!(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
	return;

	ino = (group * fs->super->s_inodes_per_group) + 1;
	for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
	ext2fs_fast_unmark_inode_bitmap2(map, ino);

	ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
	/* Mimics what the kernel does */
	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
	ext2fs_group_desc_csum_set(fs, group);
	ext2fs_mark_ib_dirty(fs);
	ext2fs_mark_super_dirty(fs);
	}

	/*
	* Right now, just search forward from the parent directory's block
	* group to find the next free inode.
	*
	* Should have a special policy for directories.
	*/
	errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
	int mode EXT2FS_ATTR((unused)),
	ext2fs_inode_bitmap map, ext2_ino_t *ret)
	{
	ext2_ino_t start_inode = 0;
	ext2_ino_t i, ino_in_group, upto, first_zero;
	errcode_t retval;
	dgrp_t group;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
	map = fs->inode_map;
	if (!map)
	return EXT2_ET_NO_INODE_BITMAP;

	if (dir > 0) {
	group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
	start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
	}
	if (start_inode < EXT2_FIRST_INODE(fs->super))
	start_inode = EXT2_FIRST_INODE(fs->super);
	if (start_inode > fs->super->s_inodes_count)
	return EXT2_ET_INODE_ALLOC_FAIL;
	i = start_inode;
	do {
	ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
	group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);

	check_inode_uninit(fs, map, group);
	upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
	if (i < start_inode && upto >= start_inode)
	upto = start_inode - 1;
	if (upto > fs->super->s_inodes_count)
	upto = fs->super->s_inodes_count;

	retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
	&first_zero);
	if (retval == 0) {
	i = first_zero;
	break;
	}
	if (retval != ENOENT)
	return EXT2_ET_INODE_ALLOC_FAIL;
	i = upto + 1;
	if (i > fs->super->s_inodes_count)
	i = EXT2_FIRST_INODE(fs->super);
	} while (i != start_inode);

	if (ext2fs_test_inode_bitmap2(map, i))
	return EXT2_ET_INODE_ALLOC_FAIL;
	*ret = i;
	return 0;
	}

	/*
	* Stupid algorithm --- we now just search forward starting from the
	* goal. Should put in a smarter one someday....
	*/
	errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
	ext2fs_block_bitmap map, blk64_t *ret)
	{
	errcode_t retval;
	blk64_t b = 0;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
	map = fs->block_map;
	if (!map)
	return EXT2_ET_NO_BLOCK_BITMAP;
	if (!goal \|\| (goal >= ext2fs_blocks_count(fs->super)))
	goal = fs->super->s_first_data_block;
	goal &= ~EXT2FS_CLUSTER_MASK(fs);

	retval = ext2fs_find_first_zero_block_bitmap2(map,
	goal, ext2fs_blocks_count(fs->super) - 1, &b);
	if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
	retval = ext2fs_find_first_zero_block_bitmap2(map,
	fs->super->s_first_data_block, goal - 1, &b);
	if (retval == ENOENT)
	return EXT2_ET_BLOCK_ALLOC_FAIL;
	if (retval)
	return retval;

	clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
	*ret = b;
	return 0;
	}

	errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
	ext2fs_block_bitmap map, blk_t *ret)
	{
	errcode_t retval;
	blk64_t val;
	retval = ext2fs_new_block2(fs, goal, map, &val);
	if (!retval)
	*ret = (blk_t) val;
	return retval;
	}

	/*
	* This function zeros out the allocated block, and updates all of the
	* appropriate filesystem records.
	*/
	errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
	char block_buf, blk64_t ret)
	{
	errcode_t retval;
	blk64_t block;
	char *buf = 0;

	if (!block_buf) {
	retval = ext2fs_get_mem(fs->blocksize, &buf);
	if (retval)
	return retval;
	block_buf = buf;
	}
	memset(block_buf, 0, fs->blocksize);

	if (fs->get_alloc_block) {
	retval = (fs->get_alloc_block)(fs, goal, &block);
	if (retval)
	goto fail;
	} else {
	if (!fs->block_map) {
	retval = ext2fs_read_block_bitmap(fs);
	if (retval)
	goto fail;
	}

	retval = ext2fs_new_block2(fs, goal, 0, &block);
	if (retval)
	goto fail;
	}

	retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
	if (retval)
	goto fail;

	ext2fs_block_alloc_stats2(fs, block, +1);
	*ret = block;

	fail:
	if (buf)
	ext2fs_free_mem(&buf);
	return retval;
	}

	errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
	char block_buf, blk_t ret)
	{
	errcode_t retval;
	blk64_t val;
	retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
	if (!retval)
	*ret = (blk_t) val;
	return retval;
	}

	errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
	int num, ext2fs_block_bitmap map, blk64_t *ret)
	{
	blk64_t b = start;
	int c_ratio;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
	map = fs->block_map;
	if (!map)
	return EXT2_ET_NO_BLOCK_BITMAP;
	if (!b)
	b = fs->super->s_first_data_block;
	if (!finish)
	finish = start;
	if (!num)
	num = 1;
	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
	b &= ~(c_ratio - 1);
	finish &= ~(c_ratio -1);
	do {
	if (b + num - 1 >= ext2fs_blocks_count(fs->super)) {
	if (finish > start)
	return EXT2_ET_BLOCK_ALLOC_FAIL;
	b = fs->super->s_first_data_block;
	}
	if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
	*ret = b;
	return 0;
	}
	b += c_ratio;
	} while (b != finish);
	return EXT2_ET_BLOCK_ALLOC_FAIL;
	}

	errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
	int num, ext2fs_block_bitmap map, blk_t *ret)
	{
	errcode_t retval;
	blk64_t val;
	retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
	if(!retval)
	*ret = (blk_t) val;
	return retval;
	}

	void ext2fs_set_alloc_block_callback(ext2_filsys fs,
	errcode_t (*func)(ext2_filsys fs,
	blk64_t goal,
	blk64_t *ret),
	errcode_t (**old)(ext2_filsys fs,
	blk64_t goal,
	blk64_t *ret))
	{
	if (!fs \|\| fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
	return;

	if (old)
	*old = fs->get_alloc_block;

	fs->get_alloc_block = func;
	}