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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*
* fatent.c: exFAT FAT entry manager
*/
#include <asm/unaligned.h>
#include "exfat.h"
#include "core.h"
/* All buffer structures are protected w/ fsi->v_sem */
static inline bool is_reserved_clus(u32 clus)
{
if (IS_CLUS_FREE(clus))
return true;
if (IS_CLUS_EOF(clus))
return true;
if (IS_CLUS_BAD(clus))
return true;
return false;
}
static inline bool is_valid_clus(FS_INFO_T *fsi, u32 clus)
{
if (clus < CLUS_BASE || fsi->num_clusters <= clus)
return false;
return true;
}
s32 exfat_ent_get(struct super_block *sb, u32 loc, u32 *content)
{
FS_INFO_T *fsi = &(EXFAT_SB(sb)->fsi);
u32 off, _content;
u64 sec;
u8 *fat_sector;
if (!is_valid_clus(fsi, loc)) {
exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", loc);
return -EIO;
}
sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2));
off = (loc << 2) & (u32)(sb->s_blocksize - 1);
fat_sector = exfat_fcache_getblk(sb, sec);
if (!fat_sector) {
exfat_fs_error(sb, "failed to access to FAT "
"(entry 0x%08x)", loc);
return -EIO;
}
_content = le32_to_cpu(*(__le32 *)(&fat_sector[off]));
/* remap reserved clusters to simplify code */
if (_content >= CLUSTER_32(0xFFFFFFF8))
_content = CLUS_EOF;
*content = CLUSTER_32(_content);
if (!is_reserved_clus(*content) && !is_valid_clus(fsi, *content)) {
exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x) "
"bogus content (0x%08x)", loc, *content);
return -EIO;
}
return 0;
}
s32 exfat_ent_set(struct super_block *sb, u32 loc, u32 content)
{
u32 off;
u64 sec;
u8 *fat_sector;
__le32 *fat_entry;
FS_INFO_T *fsi = &(EXFAT_SB(sb)->fsi);
sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2));
off = (loc << 2) & (u32)(sb->s_blocksize - 1);
fat_sector = exfat_fcache_getblk(sb, sec);
if (!fat_sector)
return -EIO;
fat_entry = (__le32 *)&(fat_sector[off]);
*fat_entry = cpu_to_le32(content);
return exfat_fcache_modify(sb, sec);
}
s32 exfat_ent_get_safe(struct super_block *sb, u32 loc, u32 *content)
{
s32 err = exfat_ent_get(sb, loc, content);
if (err)
return err;
if (IS_CLUS_FREE(*content)) {
exfat_fs_error(sb, "invalid access to FAT free cluster "
"(entry 0x%08x)", loc);
return -EIO;
}
if (IS_CLUS_BAD(*content)) {
exfat_fs_error(sb, "invalid access to FAT bad cluster "
"(entry 0x%08x)", loc);
return -EIO;
}
return 0;
}
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