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// 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/bitmap.h>
#include <linux/buffer_head.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
#if BITS_PER_LONG == 32
#define __le_long __le32
#define lel_to_cpu(A) le32_to_cpu(A)
#define cpu_to_lel(A) cpu_to_le32(A)
#elif BITS_PER_LONG == 64
#define __le_long __le64
#define lel_to_cpu(A) le64_to_cpu(A)
#define cpu_to_lel(A) cpu_to_le64(A)
#else
#error "BITS_PER_LONG not 32 or 64"
#endif
/*
* 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_err(sb, "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 = kvmalloc_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++]);
kvfree(sbi->vol_amap);
sbi->vol_amap = NULL;
return -EIO;
}
}
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);
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;
for (i = 0; i < sbi->map_sectors; i++)
__brelse(sbi->vol_amap[i]);
kvfree(sbi->vol_amap);
}
int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
{
int i, b;
unsigned int ent_idx;
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
if (!is_valid_cluster(sbi, clu))
return -EINVAL;
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(sbi->vol_amap[i], sync);
return 0;
}
void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
{
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;
if (!is_valid_cluster(sbi, clu))
return;
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(sbi->vol_amap[i], sync);
if (opts->discard) {
int ret_discard;
ret_discard = sb_issue_discard(sb,
exfat_cluster_to_sector(sbi, clu),
(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
if (ret_discard == -EOPNOTSUPP) {
exfat_err(sb, "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 long clu_bits, clu_mask;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
__le_long bitval;
WARN_ON(clu < EXFAT_FIRST_CLUSTER);
ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
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_LONG) {
bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
if (clu_mask > 0) {
bitval |= cpu_to_lel(clu_mask);
clu_mask = 0;
}
if (lel_to_cpu(bitval) != ULONG_MAX) {
clu_bits = lel_to_cpu(bitval);
clu_free = clu_base + ffz(clu_bits);
if (clu_free < sbi->num_clusters)
return clu_free;
}
clu_base += BITS_PER_LONG;
map_b += sizeof(long);
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_LONG - 1);
unsigned long *bitmap, clu_bits;
total_clus &= ~last_mask;
for (i = 0; i < total_clus; i += BITS_PER_LONG) {
bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
count += hweight_long(*bitmap);
map_b += sizeof(long);
if (map_b >= (unsigned int)sb->s_blocksize) {
map_i++;
map_b = 0;
}
}
if (last_mask) {
bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
clu_bits = lel_to_cpu(*(__le_long *)bitmap);
count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
}
*ret_count = count;
return 0;
}
int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
{
unsigned int trim_begin, trim_end, count, next_free_clu;
u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
int err = 0;
clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
EXFAT_FIRST_CLUSTER);
clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
trim_minlen = range->minlen >> sbi->cluster_size_bits;
if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
return -EINVAL;
if (clu_end >= sbi->num_clusters)
clu_end = sbi->num_clusters - 1;
mutex_lock(&sbi->bitmap_lock);
trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
if (trim_begin == EXFAT_EOF_CLUSTER)
goto unlock;
next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
if (next_free_clu == EXFAT_EOF_CLUSTER)
goto unlock;
do {
if (next_free_clu == trim_end + 1) {
/* extend trim range for continuous free cluster */
trim_end++;
} else {
/* trim current range if it's larger than trim_minlen */
count = trim_end - trim_begin + 1;
if (count >= trim_minlen) {
err = sb_issue_discard(sb,
exfat_cluster_to_sector(sbi, trim_begin),
count * sbi->sect_per_clus, GFP_NOFS, 0);
if (err)
goto unlock;
trimmed_total += count;
}
/* set next start point of the free hole */
trim_begin = trim_end = next_free_clu;
}
if (next_free_clu >= clu_end)
break;
if (fatal_signal_pending(current)) {
err = -ERESTARTSYS;
goto unlock;
}
next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
} while (next_free_clu != EXFAT_EOF_CLUSTER &&
next_free_clu > trim_end);
/* try to trim remainder */
count = trim_end - trim_begin + 1;
if (count >= trim_minlen) {
err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
count * sbi->sect_per_clus, GFP_NOFS, 0);
if (err)
goto unlock;
trimmed_total += count;
}
unlock:
mutex_unlock(&sbi->bitmap_lock);
range->len = trimmed_total << sbi->cluster_size_bits;
return err;
}
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