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Commit 155505c1 authored by Namjae Jeon's avatar Namjae Jeon Committed by lixiang
Browse files

exfat: add bitmap operations 



This adds the implementation of bitmap operations for exfat.

Signed-off-by: default avatarNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: default avatarSungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: default avatarPali Rohár <pali.rohar@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Git-commit: 1e49a94cf707204b66a3fb242f2814712c941f52
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/


Change-Id: I6b3f723d89f772d70ff8468ef7bc5d944c25d21f
Signed-off-by: default avatarlixiang <lixiang@codeaurora.org>
parent 58680258

fs/exfat/balloc.c

0 → 100644
+280 −0
Original line number Original line Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.

 */



#include <linux/blkdev.h>

#include <linux/slab.h>

#include <linux/buffer_head.h>



#include "exfat_raw.h"

#include "exfat_fs.h"



static const unsigned char free_bit[] = {

	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*  0 ~  19*/

	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~  39*/

	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~  59*/

	0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~  79*/

	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~  99*/

	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/

	0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/

	0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/

	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/

	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/

	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/

	0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/

	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0                /*240 ~ 254*/

};



static const unsigned char used_bit[] = {

	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/*  0 ~  19*/

	2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~  39*/

	2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~  59*/

	4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~  79*/

	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~  99*/

	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/

	4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/

	3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/

	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/

	4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/

	3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/

	5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/

	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8             /*240 ~ 255*/

};



/*

 *  Allocation Bitmap Management Functions

 */

static int exfat_allocate_bitmap(struct super_block *sb,

		struct exfat_dentry *ep)

{

	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	long long map_size;

	unsigned int i, need_map_size;

	sector_t sector;



	sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);

	map_size = le64_to_cpu(ep->dentry.bitmap.size);

	need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)

		+ 1;

	if (need_map_size != map_size) {

		exfat_msg(sb, KERN_ERR,

				"bogus allocation bitmap size(need : %u, cur : %lld)",

				need_map_size, map_size);

		/*

		 * Only allowed when bogus allocation

		 * bitmap size is large

		 */

		if (need_map_size > map_size)

			return -EIO;

	}

	sbi->map_sectors = ((need_map_size - 1) >>

			(sb->s_blocksize_bits)) + 1;

	sbi->vol_amap = kmalloc_array(sbi->map_sectors,

				sizeof(struct buffer_head *), GFP_KERNEL);

	if (!sbi->vol_amap)

		return -ENOMEM;



	sector = exfat_cluster_to_sector(sbi, sbi->map_clu);

	for (i = 0; i < sbi->map_sectors; i++) {

		sbi->vol_amap[i] = sb_bread(sb, sector + i);

		if (!sbi->vol_amap[i]) {

			/* release all buffers and free vol_amap */

			int j = 0;



			while (j < i)

				brelse(sbi->vol_amap[j++]);



			kfree(sbi->vol_amap);

			sbi->vol_amap = NULL;

			return -EIO;

		}

	}



	sbi->pbr_bh = NULL;

	return 0;

}



int exfat_load_bitmap(struct super_block *sb)

{

	unsigned int i, type;

	struct exfat_chain clu;

	struct exfat_sb_info *sbi = EXFAT_SB(sb);



	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);

	while (clu.dir != EXFAT_EOF_CLUSTER) {

		for (i = 0; i < sbi->dentries_per_clu; i++) {

			struct exfat_dentry *ep;

			struct buffer_head *bh;



			ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);

			if (!ep)

				return -EIO;



			type = exfat_get_entry_type(ep);

			if (type == TYPE_UNUSED)

				break;

			if (type != TYPE_BITMAP)

				continue;

			if (ep->dentry.bitmap.flags == 0x0) {

				int err;



				err = exfat_allocate_bitmap(sb, ep);

				brelse(bh);

				return err;

			}

			brelse(bh);

		}



		if (exfat_get_next_cluster(sb, &clu.dir))

			return -EIO;

	}



	return -EINVAL;

}



void exfat_free_bitmap(struct exfat_sb_info *sbi)

{

	int i;



	brelse(sbi->pbr_bh);



	for (i = 0; i < sbi->map_sectors; i++)

		__brelse(sbi->vol_amap[i]);



	kfree(sbi->vol_amap);

}



/*

 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of

 * the cluster heap.

 */

int exfat_set_bitmap(struct inode *inode, unsigned int clu)

{

	int i, b;

	unsigned int ent_idx;

	struct super_block *sb = inode->i_sb;

	struct exfat_sb_info *sbi = EXFAT_SB(sb);



	WARN_ON(clu < EXFAT_FIRST_CLUSTER);

	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);

	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);

	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);



	set_bit_le(b, sbi->vol_amap[i]->b_data);

	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));

	return 0;

}



/*

 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of

 * the cluster heap.

 */

void exfat_clear_bitmap(struct inode *inode, unsigned int clu)

{

	int i, b;

	unsigned int ent_idx;

	struct super_block *sb = inode->i_sb;

	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	struct exfat_mount_options *opts = &sbi->options;



	WARN_ON(clu < EXFAT_FIRST_CLUSTER);

	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);

	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);

	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);



	clear_bit_le(b, sbi->vol_amap[i]->b_data);

	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));



	if (opts->discard) {

		int ret_discard;



		ret_discard = sb_issue_discard(sb,

			exfat_cluster_to_sector(sbi, clu +

						EXFAT_RESERVED_CLUSTERS),

			(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);



		if (ret_discard == -EOPNOTSUPP) {

			exfat_msg(sb, KERN_ERR,

				"discard not supported by device, disabling");

			opts->discard = 0;

		}

	}

}



/*

 * If the value of "clu" is 0, it means cluster 2 which is the first cluster of

 * the cluster heap.

 */

unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)

{

	unsigned int i, map_i, map_b, ent_idx;

	unsigned int clu_base, clu_free;

	unsigned char k, clu_mask;

	struct exfat_sb_info *sbi = EXFAT_SB(sb);



	WARN_ON(clu < EXFAT_FIRST_CLUSTER);

	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);

	clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK));

	clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);



	map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);

	map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);



	for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;

	     i += BITS_PER_BYTE) {

		k = *(sbi->vol_amap[map_i]->b_data + map_b);

		if (clu_mask > 0) {

			k |= clu_mask;

			clu_mask = 0;

		}

		if (k < 0xFF) {

			clu_free = clu_base + free_bit[k];

			if (clu_free < sbi->num_clusters)

				return clu_free;

		}

		clu_base += BITS_PER_BYTE;



		if (++map_b >= sb->s_blocksize ||

		    clu_base >= sbi->num_clusters) {

			if (++map_i >= sbi->map_sectors) {

				clu_base = EXFAT_FIRST_CLUSTER;

				map_i = 0;

			}

			map_b = 0;

		}

	}



	return EXFAT_EOF_CLUSTER;

}



int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)

{

	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	unsigned int count = 0;

	unsigned int i, map_i = 0, map_b = 0;

	unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);

	unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK;

	unsigned char clu_bits;

	const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011,

		0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111};



	total_clus &= ~last_mask;

	for (i = 0; i < total_clus; i += BITS_PER_BYTE) {

		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);

		count += used_bit[clu_bits];

		if (++map_b >= (unsigned int)sb->s_blocksize) {

			map_i++;

			map_b = 0;

		}

	}



	if (last_mask) {

		clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b);

		clu_bits &= last_bit_mask[last_mask];

		count += used_bit[clu_bits];

	}



	*ret_count = count;

	return 0;

}
 
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