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core_fat.c
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/*
* 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 : core_fat.c */
/* PURPOSE : FAT-fs core code for sdFAT */
/* */
/*----------------------------------------------------------------------*/
/* NOTES */
/* */
/* */
/************************************************************************/
#include <linux/version.h>
#include <linux/blkdev.h>
#include <linux/workqueue.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include "sdfat.h"
#include "core.h"
#include <asm/byteorder.h>
#include <asm/unaligned.h>
/*----------------------------------------------------------------------*/
/* Constant & Macro Definitions */
/*----------------------------------------------------------------------*/
#define MAX_LFN_ORDER (20)
/*
* MAX_EST_AU_SECT should be changed according to 32/64bits.
* On 32bit, 4KB page supports 512 clusters per AU.
* But, on 64bit, 4KB page can handle a half of total list_head of 32bit's.
* Bcause the size of list_head structure on 64bit increases twofold over 32bit.
*/
#if (BITS_PER_LONG == 64)
//#define MAX_EST_AU_SECT (16384) /* upto 8MB */
#define MAX_EST_AU_SECT (32768) /* upto 16MB, used more page for list_head */
#else
#define MAX_EST_AU_SECT (32768) /* upto 16MB */
#endif
/*======================================================================*/
/* Local Function Declarations */
/*======================================================================*/
static s32 __extract_uni_name_from_ext_entry(EXT_DENTRY_T *, u16 *, s32);
/*----------------------------------------------------------------------*/
/* Global Variable Definitions */
/*----------------------------------------------------------------------*/
/*----------------------------------------------------------------------*/
/* Local Variable Definitions */
/*----------------------------------------------------------------------*/
/*======================================================================*/
/* Local Function Definitions */
/*======================================================================*/
static u32 __calc_default_au_size(struct super_block *sb)
{
struct block_device *bdev = sb->s_bdev;
struct gendisk *disk;
struct request_queue *queue;
struct queue_limits *limit;
unsigned int est_au_sect = MAX_EST_AU_SECT;
unsigned int est_au_size = 0;
unsigned int queue_au_size = 0;
sector_t total_sect = 0;
/* we assumed that sector size is 512 bytes */
disk = bdev->bd_disk;
if (!disk)
goto out;
queue = disk->queue;
if (!queue)
goto out;
limit = &queue->limits;
queue_au_size = limit->discard_granularity;
/* estimate function(x) =
* (total_sect / 2) * 512 / 1024
* => (total_sect >> 1) >> 1)
* => (total_sect >> 2)
* => estimated bytes size
*
* ex1) <= 8GB -> 4MB
* ex2) 16GB -> 8MB
* ex3) >= 32GB -> 16MB
*/
total_sect = disk->part0.nr_sects;
est_au_size = total_sect >> 2;
/* au_size assumed that bytes per sector is 512 */
est_au_sect = est_au_size >> 9;
MMSG("DBG1: total_sect(%llu) est_au_size(%u) est_au_sect(%u)\n",
(u64)total_sect, est_au_size, est_au_sect);
if (est_au_sect <= 8192) {
/* 4MB */
est_au_sect = 8192;
} else if (est_au_sect <= 16384) {
/* 8MB */
est_au_sect = 16384;
} else {
/* 8MB or 16MB */
est_au_sect = MAX_EST_AU_SECT;
}
MMSG("DBG2: total_sect(%llu) est_au_size(%u) est_au_sect(%u)\n",
(u64)total_sect, est_au_size, est_au_sect);
if (est_au_size < queue_au_size &&
queue_au_size <= (MAX_EST_AU_SECT << 9)) {
DMSG("use queue_au_size(%u) instead of est_au_size(%u)\n",
queue_au_size, est_au_size);
est_au_sect = queue_au_size >> 9;
}
out:
if (sb->s_blocksize != 512) {
ASSERT(sb->s_blocksize_bits > 9);
sdfat_log_msg(sb, KERN_INFO,
"adjustment est_au_size by logical block size(%lu)",
sb->s_blocksize);
est_au_sect >>= (sb->s_blocksize_bits - 9);
}
sdfat_log_msg(sb, KERN_INFO, "set default AU sectors : %u "
"(queue_au_size : %u KB, disk_size : %llu MB)",
est_au_sect, queue_au_size >> 10, (u64)(total_sect >> 11));
return est_au_sect;
}
/*
* Cluster Management Functions
*/
static s32 fat_free_cluster(struct super_block *sb, CHAIN_T *p_chain, s32 do_relse)
{
s32 ret = -EIO;
s32 num_clusters = 0;
u32 clu, prev;
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
s32 i;
u64 sector;
/* invalid cluster number */
if (IS_CLUS_FREE(p_chain->dir) || IS_CLUS_EOF(p_chain->dir))
return 0;
/* no cluster to truncate */
if (!p_chain->size) {
DMSG("%s: cluster(%u) truncation is not required.",
__func__, p_chain->dir);
return 0;
}
/* check cluster validation */
if (!is_valid_clus(fsi, p_chain->dir)) {
EMSG("%s: invalid start cluster (%u)\n", __func__, p_chain->dir);
sdfat_debug_bug_on(1);
return -EIO;
}
set_sb_dirty(sb);
clu = p_chain->dir;
do {
if (do_relse) {
sector = CLUS_TO_SECT(fsi, clu);
for (i = 0; i < fsi->sect_per_clus; i++) {
if (dcache_release(sb, sector+i) == -EIO)
goto out;
}
}
prev = clu;
if (get_next_clus_safe(sb, &clu)) {
/* print more helpful log */
if (IS_CLUS_BAD(clu)) {
sdfat_log_msg(sb, KERN_ERR, "%s : "
"deleting bad cluster (clu[%u]->BAD)",
__func__, prev);
} else if (IS_CLUS_FREE(clu)) {
sdfat_log_msg(sb, KERN_ERR, "%s : "
"deleting free cluster (clu[%u]->FREE)",
__func__, prev);
}
goto out;
}
/* Free FAT chain */
if (fat_ent_set(sb, prev, CLUS_FREE))
goto out;
/* Update AMAP if needed */
if (fsi->amap) {
if (amap_release_cluster(sb, prev))
return -EIO;
}
num_clusters++;
} while (!IS_CLUS_EOF(clu));
/* success */
ret = 0;
out:
fsi->used_clusters -= num_clusters;
return ret;
} /* end of fat_free_cluster */
static s32 fat_alloc_cluster(struct super_block *sb, u32 num_alloc, CHAIN_T *p_chain, s32 dest)
{
s32 ret = -ENOSPC;
u32 i, num_clusters = 0, total_cnt;
u32 new_clu, last_clu = CLUS_EOF, read_clu;
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
total_cnt = fsi->num_clusters - CLUS_BASE;
if (unlikely(total_cnt < fsi->used_clusters)) {
sdfat_fs_error_ratelimit(sb,
"%s : invalid used clusters(t:%u,u:%u)\n",
__func__, total_cnt, fsi->used_clusters);
return -EIO;
}
if (num_alloc > total_cnt - fsi->used_clusters)
return -ENOSPC;
new_clu = p_chain->dir;
if (IS_CLUS_EOF(new_clu))
new_clu = fsi->clu_srch_ptr;
else if (new_clu >= fsi->num_clusters)
new_clu = CLUS_BASE;
set_sb_dirty(sb);
p_chain->dir = CLUS_EOF;
for (i = CLUS_BASE; i < fsi->num_clusters; i++) {
if (fat_ent_get(sb, new_clu, &read_clu)) {
ret = -EIO;
goto error;
}
if (IS_CLUS_FREE(read_clu)) {
if (fat_ent_set(sb, new_clu, CLUS_EOF)) {
ret = -EIO;
goto error;
}
num_clusters++;
if (IS_CLUS_EOF(p_chain->dir)) {
p_chain->dir = new_clu;
} else {
if (fat_ent_set(sb, last_clu, new_clu)) {
ret = -EIO;
goto error;
}
}
last_clu = new_clu;
if ((--num_alloc) == 0) {
fsi->clu_srch_ptr = new_clu;
fsi->used_clusters += num_clusters;
return 0;
}
}
if ((++new_clu) >= fsi->num_clusters)
new_clu = CLUS_BASE;
}
error:
if (num_clusters)
fat_free_cluster(sb, p_chain, 0);
return ret;
} /* end of fat_alloc_cluster */
static s32 fat_count_used_clusters(struct super_block *sb, u32 *ret_count)
{
s32 i;
u32 clu, count = 0;
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
for (i = CLUS_BASE; i < fsi->num_clusters; i++) {
if (fat_ent_get(sb, i, &clu))
return -EIO;
if (!IS_CLUS_FREE(clu))
count++;
}
*ret_count = count;
return 0;
} /* end of fat_count_used_clusters */
/*
* Directory Entry Management Functions
*/
static u32 fat_get_entry_type(DENTRY_T *p_entry)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
/* first byte of 32bytes dummy */
if (*(ep->name) == MSDOS_UNUSED)
return TYPE_UNUSED;
/* 0xE5 of Kanji Japanese is replaced to 0x05 */
else if (*(ep->name) == MSDOS_DELETED)
return TYPE_DELETED;
/* 11th byte of 32bytes dummy */
else if ((ep->attr & ATTR_EXTEND_MASK) == ATTR_EXTEND)
return TYPE_EXTEND;
else if (!(ep->attr & (ATTR_SUBDIR | ATTR_VOLUME)))
return TYPE_FILE;
else if ((ep->attr & (ATTR_SUBDIR | ATTR_VOLUME)) == ATTR_SUBDIR)
return TYPE_DIR;
else if ((ep->attr & (ATTR_SUBDIR | ATTR_VOLUME)) == ATTR_VOLUME)
return TYPE_VOLUME;
return TYPE_INVALID;
} /* end of fat_get_entry_type */
static void fat_set_entry_type(DENTRY_T *p_entry, u32 type)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
if (type == TYPE_UNUSED)
*(ep->name) = MSDOS_UNUSED; /* 0x0 */
else if (type == TYPE_DELETED)
*(ep->name) = MSDOS_DELETED; /* 0xE5 */
else if (type == TYPE_EXTEND)
ep->attr = ATTR_EXTEND;
else if (type == TYPE_DIR)
ep->attr = ATTR_SUBDIR;
else if (type == TYPE_FILE)
ep->attr = ATTR_ARCHIVE;
else if (type == TYPE_SYMLINK)
ep->attr = ATTR_ARCHIVE | ATTR_SYMLINK;
} /* end of fat_set_entry_type */
static u32 fat_get_entry_attr(DENTRY_T *p_entry)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
return (u32)ep->attr;
} /* end of fat_get_entry_attr */
static void fat_set_entry_attr(DENTRY_T *p_entry, u32 attr)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
ep->attr = (u8)attr;
} /* end of fat_set_entry_attr */
static u8 fat_get_entry_flag(DENTRY_T *p_entry)
{
return 0x01;
} /* end of fat_get_entry_flag */
static void fat_set_entry_flag(DENTRY_T *p_entry, u8 flags)
{
} /* end of fat_set_entry_flag */
static u32 fat_get_entry_clu0(DENTRY_T *p_entry)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
/* FIXME : is ok? */
return(((u32)(le16_to_cpu(ep->start_clu_hi)) << 16) | le16_to_cpu(ep->start_clu_lo));
} /* end of fat_get_entry_clu0 */
static void fat_set_entry_clu0(DENTRY_T *p_entry, u32 start_clu)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
ep->start_clu_lo = cpu_to_le16(CLUSTER_16(start_clu));
ep->start_clu_hi = cpu_to_le16(CLUSTER_16(start_clu >> 16));
} /* end of fat_set_entry_clu0 */
static u64 fat_get_entry_size(DENTRY_T *p_entry)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
return (u64)le32_to_cpu(ep->size);
} /* end of fat_get_entry_size */
static void fat_set_entry_size(DENTRY_T *p_entry, u64 size)
{
DOS_DENTRY_T *ep = (DOS_DENTRY_T *)p_entry;
ep->size = cpu_to_le32((u32)size);
} /* end of fat_set_entry_size */
static void fat_get_entry_time(DENTRY_T *p_entry, TIMESTAMP_T *tp, u8 mode)
{
u16 t = 0x00, d = 0x21;
DOS_DENTRY_T *ep = (DOS_DENTRY_T *) p_entry;
switch (mode) {
case TM_CREATE:
t = le16_to_cpu(ep->create_time);
d = le16_to_cpu(ep->create_date);
break;
case TM_MODIFY:
t = le16_to_cpu(ep->modify_time);
d = le16_to_cpu(ep->modify_date);
break;
}
tp->tz.value = 0x00;
tp->sec = (t & 0x001F) << 1;
tp->min = (t >> 5) & 0x003F;
tp->hour = (t >> 11);
tp->day = (d & 0x001F);
tp->mon = (d >> 5) & 0x000F;
tp->year = (d >> 9);
} /* end of fat_get_entry_time */
static void fat_set_entry_time(DENTRY_T *p_entry, TIMESTAMP_T *tp, u8 mode)
{
u16 t, d;
DOS_DENTRY_T *ep = (DOS_DENTRY_T *) p_entry;
t = (tp->hour << 11) | (tp->min << 5) | (tp->sec >> 1);
d = (tp->year << 9) | (tp->mon << 5) | tp->day;
switch (mode) {
case TM_CREATE:
ep->create_time = cpu_to_le16(t);
ep->create_date = cpu_to_le16(d);
break;
case TM_MODIFY:
ep->modify_time = cpu_to_le16(t);
ep->modify_date = cpu_to_le16(d);
break;
}
} /* end of fat_set_entry_time */
static void __init_dos_entry(struct super_block *sb, DOS_DENTRY_T *ep, u32 type, u32 start_clu)
{
TIMESTAMP_T tm, *tp;
fat_set_entry_type((DENTRY_T *) ep, type);
ep->start_clu_lo = cpu_to_le16(CLUSTER_16(start_clu));
ep->start_clu_hi = cpu_to_le16(CLUSTER_16(start_clu >> 16));
ep->size = 0;
tp = tm_now_sb(sb, &tm);
fat_set_entry_time((DENTRY_T *) ep, tp, TM_CREATE);
fat_set_entry_time((DENTRY_T *) ep, tp, TM_MODIFY);
ep->access_date = 0;
ep->create_time_ms = 0;
} /* end of __init_dos_entry */
static void __init_ext_entry(EXT_DENTRY_T *ep, s32 order, u8 chksum, u16 *uniname)
{
s32 i;
u8 end = false;
fat_set_entry_type((DENTRY_T *) ep, TYPE_EXTEND);
ep->order = (u8) order;
ep->sysid = 0;
ep->checksum = chksum;
ep->start_clu = 0;
/* unaligned name */
for (i = 0; i < 5; i++) {
if (!end) {
put_unaligned_le16(*uniname, &(ep->unicode_0_4[i<<1]));
if (*uniname == 0x0)
end = true;
else
uniname++;
} else {
put_unaligned_le16(0xFFFF, &(ep->unicode_0_4[i<<1]));
}
}
/* aligned name */
for (i = 0; i < 6; i++) {
if (!end) {
ep->unicode_5_10[i] = cpu_to_le16(*uniname);
if (*uniname == 0x0)
end = true;
else
uniname++;
} else {
ep->unicode_5_10[i] = cpu_to_le16(0xFFFF);
}
}
/* aligned name */
for (i = 0; i < 2; i++) {
if (!end) {
ep->unicode_11_12[i] = cpu_to_le16(*uniname);
if (*uniname == 0x0)
end = true;
else
uniname++;
} else {
ep->unicode_11_12[i] = cpu_to_le16(0xFFFF);
}
}
} /* end of __init_ext_entry */
static s32 fat_init_dir_entry(struct super_block *sb, CHAIN_T *p_dir, s32 entry, u32 type,
u32 start_clu, u64 size)
{
u64 sector;
DOS_DENTRY_T *dos_ep;
dos_ep = (DOS_DENTRY_T *) get_dentry_in_dir(sb, p_dir, entry, §or);
if (!dos_ep)
return -EIO;
__init_dos_entry(sb, dos_ep, type, start_clu);
dcache_modify(sb, sector);
return 0;
} /* end of fat_init_dir_entry */
static s32 fat_init_ext_entry(struct super_block *sb, CHAIN_T *p_dir, s32 entry, s32 num_entries,
UNI_NAME_T *p_uniname, DOS_NAME_T *p_dosname)
{
s32 i;
u64 sector;
u8 chksum;
u16 *uniname = p_uniname->name;
DOS_DENTRY_T *dos_ep;
EXT_DENTRY_T *ext_ep;
dos_ep = (DOS_DENTRY_T *) get_dentry_in_dir(sb, p_dir, entry, §or);
if (!dos_ep)
return -EIO;
dos_ep->lcase = p_dosname->name_case;
memcpy(dos_ep->name, p_dosname->name, DOS_NAME_LENGTH);
if (dcache_modify(sb, sector))
return -EIO;
if ((--num_entries) > 0) {
chksum = calc_chksum_1byte((void *) dos_ep->name, DOS_NAME_LENGTH, 0);
for (i = 1; i < num_entries; i++) {
ext_ep = (EXT_DENTRY_T *) get_dentry_in_dir(sb, p_dir, entry-i, §or);
if (!ext_ep)
return -EIO;
__init_ext_entry(ext_ep, i, chksum, uniname);
if (dcache_modify(sb, sector))
return -EIO;
uniname += 13;
}
ext_ep = (EXT_DENTRY_T *) get_dentry_in_dir(sb, p_dir, entry-i, §or);
if (!ext_ep)
return -EIO;
__init_ext_entry(ext_ep, i+MSDOS_LAST_LFN, chksum, uniname);
if (dcache_modify(sb, sector))
return -EIO;
}
return 0;
} /* end of fat_init_ext_entry */
static s32 fat_delete_dir_entry(struct super_block *sb, CHAIN_T *p_dir, s32 entry, s32 order, s32 num_entries)
{
s32 i;
u64 sector;
DENTRY_T *ep;
for (i = num_entries-1; i >= order; i--) {
ep = get_dentry_in_dir(sb, p_dir, entry-i, §or);
if (!ep)
return -EIO;
fat_set_entry_type(ep, TYPE_DELETED);
if (dcache_modify(sb, sector))
return -EIO;
}
return 0;
}
/* return values of fat_find_dir_entry()
* >= 0 : return dir entiry position with the name in dir
* -EEXIST : (root dir, ".") it is the root dir itself
* -ENOENT : entry with the name does not exist
* -EIO : I/O error
*/
static inline s32 __get_dentries_per_clu(FS_INFO_T *fsi, s32 clu)
{
if (IS_CLUS_FREE(clu)) /* FAT16 root_dir */
return fsi->dentries_in_root;
return fsi->dentries_per_clu;
}
static s32 fat_find_dir_entry(struct super_block *sb, FILE_ID_T *fid,
CHAIN_T *p_dir, UNI_NAME_T *p_uniname, s32 num_entries, DOS_NAME_T *p_dosname, u32 type)
{
s32 i, rewind = 0, dentry = 0, end_eidx = 0;
s32 chksum = 0, lfn_ord = 0, lfn_len = 0;
s32 dentries_per_clu, num_empty = 0;
u32 entry_type;
u16 entry_uniname[14], *uniname = NULL;
CHAIN_T clu;
DENTRY_T *ep;
HINT_T *hint_stat = &fid->hint_stat;
HINT_FEMP_T candi_empty;
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
/*
* REMARK:
* DOT and DOTDOT are handled by VFS layer
*/
dentries_per_clu = __get_dentries_per_clu(fsi, p_dir->dir);
clu.dir = p_dir->dir;
clu.flags = p_dir->flags;
if (hint_stat->eidx) {
clu.dir = hint_stat->clu;
dentry = hint_stat->eidx;
end_eidx = dentry;
}
candi_empty.eidx = -1;
MMSG("lookup dir= %s\n", p_dosname->name);
rewind:
while (!IS_CLUS_EOF(clu.dir)) {
i = dentry % dentries_per_clu;
for (; i < dentries_per_clu; i++, dentry++) {
if (rewind && (dentry == end_eidx))
goto not_found;
ep = get_dentry_in_dir(sb, &clu, i, NULL);
if (!ep)
return -EIO;
entry_type = fat_get_entry_type(ep);
/*
* Most directory entries have long name,
* So, we check extend directory entry first.
*/
if (entry_type == TYPE_EXTEND) {
EXT_DENTRY_T *ext_ep = (EXT_DENTRY_T *)ep;
u32 cur_ord = (u32)ext_ep->order;
u32 cur_chksum = (s32)ext_ep->checksum;
s32 len = 13;
u16 unichar;
num_empty = 0;
candi_empty.eidx = -1;
/* check whether new lfn or not */
if (cur_ord & MSDOS_LAST_LFN) {
cur_ord &= ~(MSDOS_LAST_LFN);
chksum = cur_chksum;
len = (13 * (cur_ord-1));
uniname = (p_uniname->name + len);
lfn_ord = cur_ord + 1;
lfn_len = 0;
/* check minimum name length */
if (cur_ord &&
(len > p_uniname->name_len)) {
/* MISMATCHED NAME LENGTH */
lfn_len = -1;
}
len = 0;
}
/* invalid lfn order */
if (!cur_ord || (cur_ord > MAX_LFN_ORDER) ||
((cur_ord + 1) != lfn_ord))
goto reset_dentry_set;
/* check checksum of directory entry set */
if (cur_chksum != chksum)
goto reset_dentry_set;
/* update order for next dentry */
lfn_ord = cur_ord;
/* check whether mismatched lfn or not */
if (lfn_len == -1) {
/* MISMATCHED LFN DENTRY SET */
continue;
}
if (!uniname) {
sdfat_fs_error(sb,
"%s : abnormal dentry "
"(start_clu[%u], "
"idx[%u])", __func__,
p_dir->dir, dentry);
sdfat_debug_bug_on(1);
return -EIO;
}
/* update position of name buffer */
uniname -= len;
/* get utf16 characters saved on this entry */
len = __extract_uni_name_from_ext_entry(ext_ep, entry_uniname, lfn_ord);
/* replace last char to null */
unichar = *(uniname+len);
*(uniname+len) = (u16)0x0;
/* uniname ext_dentry unit compare repeatdly */
if (nls_cmp_uniname(sb, uniname, entry_uniname)) {
/* DO HANDLE WRONG NAME */
lfn_len = -1;
} else {
/* add matched chars length */
lfn_len += len;
}
/* restore previous character */
*(uniname+len) = unichar;
/* jump to check next dentry */
continue;
} else if ((entry_type == TYPE_FILE) || (entry_type == TYPE_DIR)) {
DOS_DENTRY_T *dos_ep = (DOS_DENTRY_T *)ep;
u32 cur_chksum = (s32)calc_chksum_1byte(
(void *) dos_ep->name,
DOS_NAME_LENGTH, 0);
num_empty = 0;
candi_empty.eidx = -1;
MMSG("checking dir= %c%c%c%c%c%c%c%c%c%c%c\n",
dos_ep->name[0], dos_ep->name[1],
dos_ep->name[2], dos_ep->name[3],
dos_ep->name[4], dos_ep->name[5],
dos_ep->name[6], dos_ep->name[7],
dos_ep->name[8], dos_ep->name[9],
dos_ep->name[10]);
/*
* if there is no valid long filename,
* we should check short filename.
*/
if (!lfn_len || (cur_chksum != chksum)) {
/* check shortname */
if ((p_dosname->name[0] != '\0') &&
!nls_cmp_sfn(sb,
p_dosname->name,
dos_ep->name)) {
goto found;
}
/* check name length */
} else if ((lfn_len > 0) &&
((s32)p_uniname->name_len ==
lfn_len)) {
goto found;
}
/* DO HANDLE MISMATCHED SFN, FALL THROUGH */
} else if ((entry_type == TYPE_UNUSED) || (entry_type == TYPE_DELETED)) {
num_empty++;
if (candi_empty.eidx == -1) {
if (num_empty == 1) {
candi_empty.cur.dir = clu.dir;
candi_empty.cur.size = clu.size;
candi_empty.cur.flags = clu.flags;
}
if (num_empty >= num_entries) {
candi_empty.eidx = dentry - (num_empty - 1);
ASSERT(0 <= candi_empty.eidx);
candi_empty.count = num_empty;
if ((fid->hint_femp.eidx == -1) ||
(candi_empty.eidx <= fid->hint_femp.eidx)) {
memcpy(&fid->hint_femp,
&candi_empty,
sizeof(HINT_FEMP_T));
}
}
}
if (entry_type == TYPE_UNUSED)
goto not_found;
/* FALL THROUGH */
}
reset_dentry_set:
/* TYPE_DELETED, TYPE_VOLUME OR MISMATCHED SFN */
lfn_ord = 0;
lfn_len = 0;
chksum = 0;
}
if (IS_CLUS_FREE(p_dir->dir))
break; /* FAT16 root_dir */
if (get_next_clus_safe(sb, &clu.dir))
return -EIO;
}
not_found:
/* we started at not 0 index,so we should try to find target
* from 0 index to the index we started at.
*/
if (!rewind && end_eidx) {
rewind = 1;
dentry = 0;
clu.dir = p_dir->dir;
/* reset dentry set */
lfn_ord = 0;
lfn_len = 0;
chksum = 0;
/* reset empty hint_*/
num_empty = 0;
candi_empty.eidx = -1;
goto rewind;
}
/* initialized hint_stat */
hint_stat->clu = p_dir->dir;
hint_stat->eidx = 0;
return -ENOENT;
found:
/* next dentry we'll find is out of this cluster */
if (!((dentry + 1) % dentries_per_clu)) {
int ret = 0;
/* FAT16 root_dir */
if (IS_CLUS_FREE(p_dir->dir))
clu.dir = CLUS_EOF;
else
ret = get_next_clus_safe(sb, &clu.dir);
if (ret || IS_CLUS_EOF(clu.dir)) {
/* just initialized hint_stat */
hint_stat->clu = p_dir->dir;
hint_stat->eidx = 0;
return dentry;
}
}
hint_stat->clu = clu.dir;
hint_stat->eidx = dentry + 1;
return dentry;
} /* end of fat_find_dir_entry */
/* returns -EIO on error */
static s32 fat_count_ext_entries(struct super_block *sb, CHAIN_T *p_dir, s32 entry, DENTRY_T *p_entry)
{
s32 count = 0;
u8 chksum;
DOS_DENTRY_T *dos_ep = (DOS_DENTRY_T *) p_entry;
EXT_DENTRY_T *ext_ep;
chksum = calc_chksum_1byte((void *) dos_ep->name, DOS_NAME_LENGTH, 0);
for (entry--; entry >= 0; entry--) {
ext_ep = (EXT_DENTRY_T *)get_dentry_in_dir(sb, p_dir, entry, NULL);
if (!ext_ep)
return -EIO;
if ((fat_get_entry_type((DENTRY_T *)ext_ep) == TYPE_EXTEND) &&
(ext_ep->checksum == chksum)) {
count++;
if (ext_ep->order > MSDOS_LAST_LFN)
return count;
} else {
return count;
}
}
return count;
}
/*
* Name Conversion Functions
*/
static s32 __extract_uni_name_from_ext_entry(EXT_DENTRY_T *ep, u16 *uniname, s32 order)
{
s32 i, len = 0;
for (i = 0; i < 5; i++) {
*uniname = get_unaligned_le16(&(ep->unicode_0_4[i<<1]));
if (*uniname == 0x0)
return len;
uniname++;
len++;
}
if (order < 20) {
for (i = 0; i < 6; i++) {
/* FIXME : unaligned? */
*uniname = le16_to_cpu(ep->unicode_5_10[i]);
if (*uniname == 0x0)
return len;
uniname++;
len++;
}
} else {
for (i = 0; i < 4; i++) {
/* FIXME : unaligned? */
*uniname = le16_to_cpu(ep->unicode_5_10[i]);
if (*uniname == 0x0)
return len;
uniname++;
len++;
}
*uniname = 0x0; /* uniname[MAX_NAME_LENGTH] */
return len;
}
for (i = 0; i < 2; i++) {
/* FIXME : unaligned? */
*uniname = le16_to_cpu(ep->unicode_11_12[i]);
if (*uniname == 0x0)
return len;
uniname++;
len++;
}
*uniname = 0x0;
return len;
} /* end of __extract_uni_name_from_ext_entry */
static void fat_get_uniname_from_ext_entry(struct super_block *sb, CHAIN_T *p_dir, s32 entry, u16 *uniname)
{
u32 i;
u16 *name = uniname;
u32 chksum;
DOS_DENTRY_T *dos_ep =
(DOS_DENTRY_T *)get_dentry_in_dir(sb, p_dir, entry, NULL);
if (unlikely(!dos_ep))
goto invalid_lfn;
chksum = (u32)calc_chksum_1byte(
(void *) dos_ep->name,
DOS_NAME_LENGTH, 0);
for (entry--, i = 1; entry >= 0; entry--, i++) {
EXT_DENTRY_T *ep;
ep = (EXT_DENTRY_T *)get_dentry_in_dir(sb, p_dir, entry, NULL);
if (!ep)
goto invalid_lfn;
if (fat_get_entry_type((DENTRY_T *) ep) != TYPE_EXTEND)
goto invalid_lfn;
if (chksum != (u32)ep->checksum)
goto invalid_lfn;
if (i != (u32)(ep->order & ~(MSDOS_LAST_LFN)))
goto invalid_lfn;
__extract_uni_name_from_ext_entry(ep, name, (s32)i);