diff options
Diffstat (limited to 'fs/sdfat/fatent.c')
-rw-r--r-- | fs/sdfat/fatent.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/fs/sdfat/fatent.c b/fs/sdfat/fatent.c new file mode 100644 index 000000000000..fca32a50d336 --- /dev/null +++ b/fs/sdfat/fatent.c @@ -0,0 +1,420 @@ +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +/************************************************************************/ +/* */ +/* PROJECT : exFAT & FAT12/16/32 File System */ +/* FILE : fatent.c */ +/* PURPOSE : sdFAT FAT entry manager */ +/* */ +/*----------------------------------------------------------------------*/ +/* NOTES */ +/* */ +/* */ +/************************************************************************/ + +#include <asm/unaligned.h> + +#include "sdfat.h" +#include "core.h" + +/*----------------------------------------------------------------------*/ +/* Global Variable Definitions */ +/*----------------------------------------------------------------------*/ +/* All buffer structures are protected w/ fsi->v_sem */ + +/*----------------------------------------------------------------------*/ +/* Static functions */ +/*----------------------------------------------------------------------*/ + +/*======================================================================*/ +/* FAT Read/Write Functions */ +/*======================================================================*/ +/* in : sb, loc + * out: content + * returns 0 on success, -1 on error + */ +static s32 exfat_ent_get(struct super_block *sb, u32 loc, u32 *content) +{ + u32 off, _content; + u64 sec; + u8 *fat_sector; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + /* fsi->vol_type == EXFAT */ + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2)); + off = (loc << 2) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + 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); + return 0; +} + +static 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 = &(SDFAT_SB(sb)->fsi); + + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2)); + off = (loc << 2) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + fat_entry = (__le32 *)&(fat_sector[off]); + *fat_entry = cpu_to_le32(content); + + return fcache_modify(sb, sec); +} + +#define FATENT_FAT32_VALID_MASK (0x0FFFFFFFU) +#define FATENT_FAT32_IGNORE_MASK (0xF0000000U) +static s32 fat32_ent_get(struct super_block *sb, u32 loc, u32 *content) +{ + u32 off, _content; + u64 sec; + u8 *fat_sector; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2)); + off = (loc << 2) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + _content = le32_to_cpu(*(__le32 *)(&fat_sector[off])); + _content &= FATENT_FAT32_VALID_MASK; + + /* remap reserved clusters to simplify code */ + if (_content == CLUSTER_32(0x0FFFFFF7U)) + _content = CLUS_BAD; + else if (_content >= CLUSTER_32(0x0FFFFFF8U)) + _content = CLUS_EOF; + + *content = CLUSTER_32(_content); + return 0; +} + +static s32 fat32_ent_set(struct super_block *sb, u32 loc, u32 content) +{ + u32 off; + u64 sec; + u8 *fat_sector; + __le32 *fat_entry; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + content &= FATENT_FAT32_VALID_MASK; + + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-2)); + off = (loc << 2) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + fat_entry = (__le32 *)&(fat_sector[off]); + content |= (le32_to_cpu(*fat_entry) & FATENT_FAT32_IGNORE_MASK); + *fat_entry = cpu_to_le32(content); + + return fcache_modify(sb, sec); +} + +#define FATENT_FAT16_VALID_MASK (0x0000FFFFU) +static s32 fat16_ent_get(struct super_block *sb, u32 loc, u32 *content) +{ + u32 off, _content; + u64 sec; + u8 *fat_sector; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-1)); + off = (loc << 1) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + _content = (u32)le16_to_cpu(*(__le16 *)(&fat_sector[off])); + _content &= FATENT_FAT16_VALID_MASK; + + /* remap reserved clusters to simplify code */ + if (_content == CLUSTER_16(0xFFF7U)) + _content = CLUS_BAD; + else if (_content >= CLUSTER_16(0xFFF8U)) + _content = CLUS_EOF; + + *content = CLUSTER_32(_content); + return 0; +} + +static s32 fat16_ent_set(struct super_block *sb, u32 loc, u32 content) +{ + u32 off; + u64 sec; + u8 *fat_sector; + __le16 *fat_entry; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + content &= FATENT_FAT16_VALID_MASK; + + sec = fsi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-1)); + off = (loc << 1) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + fat_entry = (__le16 *)&(fat_sector[off]); + *fat_entry = cpu_to_le16(content); + + return fcache_modify(sb, sec); +} + +#define FATENT_FAT12_VALID_MASK (0x00000FFFU) +static s32 fat12_ent_get(struct super_block *sb, u32 loc, u32 *content) +{ + u32 off, _content; + u64 sec; + u8 *fat_sector; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + sec = fsi->FAT1_start_sector + ((loc + (loc >> 1)) >> sb->s_blocksize_bits); + off = (loc + (loc >> 1)) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + if (off == (u32)(sb->s_blocksize - 1)) { + _content = (u32) fat_sector[off]; + + fat_sector = fcache_getblk(sb, ++sec); + if (!fat_sector) + return -EIO; + + _content |= (u32) fat_sector[0] << 8; + } else { + _content = get_unaligned_le16(&fat_sector[off]); + } + + if (loc & 1) + _content >>= 4; + + _content &= FATENT_FAT12_VALID_MASK; + + /* remap reserved clusters to simplify code */ + if (_content == CLUSTER_16(0x0FF7U)) + _content = CLUS_BAD; + else if (_content >= CLUSTER_16(0x0FF8U)) + _content = CLUS_EOF; + + *content = CLUSTER_32(_content); + return 0; +} + +static s32 fat12_ent_set(struct super_block *sb, u32 loc, u32 content) +{ + u32 off; + u64 sec; + u8 *fat_sector, *fat_entry; + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + content &= FATENT_FAT12_VALID_MASK; + + sec = fsi->FAT1_start_sector + ((loc + (loc >> 1)) >> sb->s_blocksize_bits); + off = (loc + (loc >> 1)) & (u32)(sb->s_blocksize - 1); + + fat_sector = fcache_getblk(sb, sec); + if (!fat_sector) + return -EIO; + + if (loc & 1) { /* odd */ + + content <<= 4; + + if (off == (u32)(sb->s_blocksize-1)) { + fat_sector[off] = (u8)(content | (fat_sector[off] & 0x0F)); + if (fcache_modify(sb, sec)) + return -EIO; + + fat_sector = fcache_getblk(sb, ++sec); + if (!fat_sector) + return -EIO; + + fat_sector[0] = (u8)(content >> 8); + } else { + fat_entry = &(fat_sector[off]); + content |= 0x000F & get_unaligned_le16(fat_entry); + put_unaligned_le16(content, fat_entry); + } + } else { /* even */ + fat_sector[off] = (u8)(content); + + if (off == (u32)(sb->s_blocksize-1)) { + fat_sector[off] = (u8)(content); + if (fcache_modify(sb, sec)) + return -EIO; + + fat_sector = fcache_getblk(sb, ++sec); + if (!fat_sector) + return -EIO; + + fat_sector[0] = (u8)((fat_sector[0] & 0xF0) | (content >> 8)); + } else { + fat_entry = &(fat_sector[off]); + content |= 0xF000 & get_unaligned_le16(fat_entry); + put_unaligned_le16(content, fat_entry); + } + } + return fcache_modify(sb, sec); +} + + +static FATENT_OPS_T fat12_ent_ops = { + fat12_ent_get, + fat12_ent_set +}; + +static FATENT_OPS_T fat16_ent_ops = { + fat16_ent_get, + fat16_ent_set +}; + +static FATENT_OPS_T fat32_ent_ops = { + fat32_ent_get, + fat32_ent_set +}; + +static FATENT_OPS_T exfat_ent_ops = { + exfat_ent_get, + exfat_ent_set +}; + +s32 fat_ent_ops_init(struct super_block *sb) +{ + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + switch (fsi->vol_type) { + case EXFAT: + fsi->fatent_ops = &exfat_ent_ops; + break; + case FAT32: + fsi->fatent_ops = &fat32_ent_ops; + break; + case FAT16: + fsi->fatent_ops = &fat16_ent_ops; + break; + case FAT12: + fsi->fatent_ops = &fat12_ent_ops; + break; + default: + fsi->fatent_ops = NULL; + EMSG("Unknown volume type : %d", (int)fsi->vol_type); + return -ENOTSUPP; + } + + return 0; +} + +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 fat_ent_get(struct super_block *sb, u32 loc, u32 *content) +{ + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + s32 err; + + if (!is_valid_clus(fsi, loc)) { + sdfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", loc); + return -EIO; + } + + err = fsi->fatent_ops->ent_get(sb, loc, content); + if (err) { + sdfat_fs_error(sb, "failed to access to FAT " + "(entry 0x%08x, err:%d)", loc, err); + return err; + } + + if (!is_reserved_clus(*content) && !is_valid_clus(fsi, *content)) { + sdfat_fs_error(sb, "invalid access to FAT (entry 0x%08x) " + "bogus content (0x%08x)", loc, *content); + return -EIO; + } + + return 0; +} + +s32 fat_ent_set(struct super_block *sb, u32 loc, u32 content) +{ + FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi); + + return fsi->fatent_ops->ent_set(sb, loc, content); +} + +s32 fat_ent_get_safe(struct super_block *sb, u32 loc, u32 *content) +{ + s32 err = fat_ent_get(sb, loc, content); + + if (err) + return err; + + if (IS_CLUS_FREE(*content)) { + sdfat_fs_error(sb, "invalid access to FAT free cluster " + "(entry 0x%08x)", loc); + return -EIO; + } + + if (IS_CLUS_BAD(*content)) { + sdfat_fs_error(sb, "invalid access to FAT bad cluster " + "(entry 0x%08x)", loc); + return -EIO; + } + + return 0; +} + +/* end of fatent.c */ |