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linux/fs/exfat/dir.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*/
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/buffer_head.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
static int exfat_extract_uni_name(struct exfat_dentry *ep,
unsigned short *uniname)
{
int i, len = 0;
for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
*uniname = le16_to_cpu(ep->dentry.name.unicode_0_14[i]);
if (*uniname == 0x0)
return len;
uniname++;
len++;
}
*uniname = 0x0;
return len;
}
static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
struct exfat_chain *p_dir, int entry, unsigned short *uniname)
{
int i;
struct exfat_entry_set_cache *es;
es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
if (!es)
return;
/*
* First entry : file entry
* Second entry : stream-extension entry
* Third entry : first file-name entry
* So, the index of first file-name dentry should start from 2.
*/
for (i = 2; i < es->num_entries; i++) {
struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
/* end of name entry */
if (exfat_get_entry_type(ep) != TYPE_EXTEND)
break;
exfat_extract_uni_name(ep, uniname);
uniname += EXFAT_FILE_NAME_LEN;
}
exfat_free_dentry_set(es, false);
}
/* read a directory entry from the opened directory */
static int exfat_readdir(struct inode *inode, struct exfat_dir_entry *dir_entry)
{
int i, dentries_per_clu, dentries_per_clu_bits = 0;
unsigned int type, clu_offset;
sector_t sector;
struct exfat_chain dir, clu;
struct exfat_uni_name uni_name;
struct exfat_dentry *ep;
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_inode_info *ei = EXFAT_I(inode);
unsigned int dentry = ei->rwoffset & 0xFFFFFFFF;
struct buffer_head *bh;
/* check if the given file ID is opened */
if (ei->type != TYPE_DIR)
return -EPERM;
if (ei->entry == -1)
exfat_chain_set(&dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
else
exfat_chain_set(&dir, ei->start_clu,
EXFAT_B_TO_CLU(i_size_read(inode), sbi), ei->flags);
dentries_per_clu = sbi->dentries_per_clu;
dentries_per_clu_bits = ilog2(dentries_per_clu);
clu_offset = dentry >> dentries_per_clu_bits;
exfat_chain_dup(&clu, &dir);
if (clu.flags == ALLOC_NO_FAT_CHAIN) {
clu.dir += clu_offset;
clu.size -= clu_offset;
} else {
/* hint_information */
if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
clu_offset -= ei->hint_bmap.off;
clu.dir = ei->hint_bmap.clu;
}
while (clu_offset > 0) {
if (exfat_get_next_cluster(sb, &(clu.dir)))
return -EIO;
clu_offset--;
}
}
while (clu.dir != EXFAT_EOF_CLUSTER) {
i = dentry & (dentries_per_clu - 1);
for ( ; i < dentries_per_clu; i++, dentry++) {
ep = exfat_get_dentry(sb, &clu, i, &bh, &sector);
if (!ep)
return -EIO;
type = exfat_get_entry_type(ep);
if (type == TYPE_UNUSED) {
brelse(bh);
break;
}
if (type != TYPE_FILE && type != TYPE_DIR) {
brelse(bh);
continue;
}
dir_entry->attr = le16_to_cpu(ep->dentry.file.attr);
exfat_get_entry_time(sbi, &dir_entry->crtime,
ep->dentry.file.create_tz,
ep->dentry.file.create_time,
ep->dentry.file.create_date,
ep->dentry.file.create_time_cs);
exfat_get_entry_time(sbi, &dir_entry->mtime,
ep->dentry.file.modify_tz,
ep->dentry.file.modify_time,
ep->dentry.file.modify_date,
ep->dentry.file.modify_time_cs);
exfat_get_entry_time(sbi, &dir_entry->atime,
ep->dentry.file.access_tz,
ep->dentry.file.access_time,
ep->dentry.file.access_date,
0);
*uni_name.name = 0x0;
exfat_get_uniname_from_ext_entry(sb, &dir, dentry,
uni_name.name);
exfat_utf16_to_nls(sb, &uni_name,
dir_entry->namebuf.lfn,
dir_entry->namebuf.lfnbuf_len);
brelse(bh);
ep = exfat_get_dentry(sb, &clu, i + 1, &bh, NULL);
if (!ep)
return -EIO;
dir_entry->size =
le64_to_cpu(ep->dentry.stream.valid_size);
brelse(bh);
ei->hint_bmap.off = dentry >> dentries_per_clu_bits;
ei->hint_bmap.clu = clu.dir;
ei->rwoffset = ++dentry;
return 0;
}
if (clu.flags == ALLOC_NO_FAT_CHAIN) {
if (--clu.size > 0)
clu.dir++;
else
clu.dir = EXFAT_EOF_CLUSTER;
} else {
if (exfat_get_next_cluster(sb, &(clu.dir)))
return -EIO;
}
}
dir_entry->namebuf.lfn[0] = '\0';
ei->rwoffset = dentry;
return 0;
}
static void exfat_init_namebuf(struct exfat_dentry_namebuf *nb)
{
nb->lfn = NULL;
nb->lfnbuf_len = 0;
}
static int exfat_alloc_namebuf(struct exfat_dentry_namebuf *nb)
{
nb->lfn = __getname();
if (!nb->lfn)
return -ENOMEM;
nb->lfnbuf_len = MAX_VFSNAME_BUF_SIZE;
return 0;
}
static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
{
if (!nb->lfn)
return;
__putname(nb->lfn);
exfat_init_namebuf(nb);
}
/* skip iterating emit_dots when dir is empty */
#define ITER_POS_FILLED_DOTS (2)
static int exfat_iterate(struct file *filp, struct dir_context *ctx)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct super_block *sb = inode->i_sb;
struct inode *tmp;
struct exfat_dir_entry de;
struct exfat_dentry_namebuf *nb = &(de.namebuf);
struct exfat_inode_info *ei = EXFAT_I(inode);
unsigned long inum;
loff_t cpos, i_pos;
int err = 0, fake_offset = 0;
exfat_init_namebuf(nb);
mutex_lock(&EXFAT_SB(sb)->s_lock);
cpos = ctx->pos;
if (!dir_emit_dots(filp, ctx))
goto unlock;
if (ctx->pos == ITER_POS_FILLED_DOTS) {
cpos = 0;
fake_offset = 1;
}
if (cpos & (DENTRY_SIZE - 1)) {
err = -ENOENT;
goto unlock;
}
/* name buffer should be allocated before use */
err = exfat_alloc_namebuf(nb);
if (err)
goto unlock;
get_new:
ei->rwoffset = EXFAT_B_TO_DEN(cpos);
if (cpos >= i_size_read(inode))
goto end_of_dir;
err = exfat_readdir(inode, &de);
if (err) {
/*
* At least we tried to read a sector. Move cpos to next sector
* position (should be aligned).
*/
if (err == -EIO) {
cpos += 1 << (sb->s_blocksize_bits);
cpos &= ~(sb->s_blocksize - 1);
}
err = -EIO;
goto end_of_dir;
}
cpos = EXFAT_DEN_TO_B(ei->rwoffset);
if (!nb->lfn[0])
goto end_of_dir;
i_pos = ((loff_t)ei->start_clu << 32) |
((ei->rwoffset - 1) & 0xffffffff);
tmp = exfat_iget(sb, i_pos);
if (tmp) {
inum = tmp->i_ino;
iput(tmp);
} else {
inum = iunique(sb, EXFAT_ROOT_INO);
}
/*
* Before calling dir_emit(), sb_lock should be released.
* Because page fault can occur in dir_emit() when the size
* of buffer given from user is larger than one page size.
*/
mutex_unlock(&EXFAT_SB(sb)->s_lock);
if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
(de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
goto out_unlocked;
mutex_lock(&EXFAT_SB(sb)->s_lock);
ctx->pos = cpos;
goto get_new;
end_of_dir:
if (!cpos && fake_offset)
cpos = ITER_POS_FILLED_DOTS;
ctx->pos = cpos;
unlock:
mutex_unlock(&EXFAT_SB(sb)->s_lock);
out_unlocked:
/*
* To improve performance, free namebuf after unlock sb_lock.
* If namebuf is not allocated, this function do nothing
*/
exfat_free_namebuf(nb);
return err;
}
const struct file_operations exfat_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate = exfat_iterate,
.fsync = generic_file_fsync,
};
int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
{
int ret;
exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
ret = exfat_alloc_cluster(inode, 1, clu);
if (ret)
return ret;
return exfat_zeroed_cluster(inode, clu->dir);
}
int exfat_calc_num_entries(struct exfat_uni_name *p_uniname)
{
int len;
len = p_uniname->name_len;
if (len == 0)
return -EINVAL;
/* 1 file entry + 1 stream entry + name entries */
return ((len - 1) / EXFAT_FILE_NAME_LEN + 3);
}
unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
{
if (ep->type == EXFAT_UNUSED)
return TYPE_UNUSED;
if (IS_EXFAT_DELETED(ep->type))
return TYPE_DELETED;
if (ep->type == EXFAT_INVAL)
return TYPE_INVALID;
if (IS_EXFAT_CRITICAL_PRI(ep->type)) {
if (ep->type == EXFAT_BITMAP)
return TYPE_BITMAP;
if (ep->type == EXFAT_UPCASE)
return TYPE_UPCASE;
if (ep->type == EXFAT_VOLUME)
return TYPE_VOLUME;
if (ep->type == EXFAT_FILE) {
if (le16_to_cpu(ep->dentry.file.attr) & ATTR_SUBDIR)
return TYPE_DIR;
return TYPE_FILE;
}
return TYPE_CRITICAL_PRI;
}
if (IS_EXFAT_BENIGN_PRI(ep->type)) {
if (ep->type == EXFAT_GUID)
return TYPE_GUID;
if (ep->type == EXFAT_PADDING)
return TYPE_PADDING;
if (ep->type == EXFAT_ACLTAB)
return TYPE_ACLTAB;
return TYPE_BENIGN_PRI;
}
if (IS_EXFAT_CRITICAL_SEC(ep->type)) {
if (ep->type == EXFAT_STREAM)
return TYPE_STREAM;
if (ep->type == EXFAT_NAME)
return TYPE_EXTEND;
if (ep->type == EXFAT_ACL)
return TYPE_ACL;
return TYPE_CRITICAL_SEC;
}
return TYPE_BENIGN_SEC;
}
static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
{
if (type == TYPE_UNUSED) {
ep->type = EXFAT_UNUSED;
} else if (type == TYPE_DELETED) {
ep->type &= EXFAT_DELETE;
} else if (type == TYPE_STREAM) {
ep->type = EXFAT_STREAM;
} else if (type == TYPE_EXTEND) {
ep->type = EXFAT_NAME;
} else if (type == TYPE_BITMAP) {
ep->type = EXFAT_BITMAP;
} else if (type == TYPE_UPCASE) {
ep->type = EXFAT_UPCASE;
} else if (type == TYPE_VOLUME) {
ep->type = EXFAT_VOLUME;
} else if (type == TYPE_DIR) {
ep->type = EXFAT_FILE;
ep->dentry.file.attr = cpu_to_le16(ATTR_SUBDIR);
} else if (type == TYPE_FILE) {
ep->type = EXFAT_FILE;
ep->dentry.file.attr = cpu_to_le16(ATTR_ARCHIVE);
}
}
static void exfat_init_stream_entry(struct exfat_dentry *ep,
unsigned char flags, unsigned int start_clu,
unsigned long long size)
{
exfat_set_entry_type(ep, TYPE_STREAM);
ep->dentry.stream.flags = flags;
ep->dentry.stream.start_clu = cpu_to_le32(start_clu);
ep->dentry.stream.valid_size = cpu_to_le64(size);
ep->dentry.stream.size = cpu_to_le64(size);
}
static void exfat_init_name_entry(struct exfat_dentry *ep,
unsigned short *uniname)
{
int i;
exfat_set_entry_type(ep, TYPE_EXTEND);
ep->dentry.name.flags = 0x0;
for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
ep->dentry.name.unicode_0_14[i] = cpu_to_le16(*uniname);
if (*uniname == 0x0)
break;
uniname++;
}
}
int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
int entry, unsigned int type, unsigned int start_clu,
unsigned long long size)
{
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct timespec64 ts = current_time(inode);
sector_t sector;
struct exfat_dentry *ep;
struct buffer_head *bh;
/*
* We cannot use exfat_get_dentry_set here because file ep is not
* initialized yet.
*/
ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
if (!ep)
return -EIO;
exfat_set_entry_type(ep, type);
exfat_set_entry_time(sbi, &ts,
&ep->dentry.file.create_tz,
&ep->dentry.file.create_time,
&ep->dentry.file.create_date,
&ep->dentry.file.create_time_cs);
exfat_set_entry_time(sbi, &ts,
&ep->dentry.file.modify_tz,
&ep->dentry.file.modify_time,
&ep->dentry.file.modify_date,
&ep->dentry.file.modify_time_cs);
exfat_set_entry_time(sbi, &ts,
&ep->dentry.file.access_tz,
&ep->dentry.file.access_time,
&ep->dentry.file.access_date,
NULL);
exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
brelse(bh);
ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
if (!ep)
return -EIO;
exfat_init_stream_entry(ep,
(type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
start_clu, size);
exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
brelse(bh);
return 0;
}
int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
int entry)
{
struct super_block *sb = inode->i_sb;
int ret = 0;
int i, num_entries;
sector_t sector;
u16 chksum;
struct exfat_dentry *ep, *fep;
struct buffer_head *fbh, *bh;
fep = exfat_get_dentry(sb, p_dir, entry, &fbh, &sector);
if (!fep)
return -EIO;
num_entries = fep->dentry.file.num_ext + 1;
chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
for (i = 1; i < num_entries; i++) {
ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
if (!ep) {
ret = -EIO;
goto release_fbh;
}
chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
CS_DEFAULT);
brelse(bh);
}
fep->dentry.file.checksum = cpu_to_le16(chksum);
exfat_update_bh(sb, fbh, IS_DIRSYNC(inode));
release_fbh:
brelse(fbh);
return ret;
}
int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
int entry, int num_entries, struct exfat_uni_name *p_uniname)
{
struct super_block *sb = inode->i_sb;
int i;
sector_t sector;
unsigned short *uniname = p_uniname->name;
struct exfat_dentry *ep;
struct buffer_head *bh;
int sync = IS_DIRSYNC(inode);
ep = exfat_get_dentry(sb, p_dir, entry, &bh, &sector);
if (!ep)
return -EIO;
ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
exfat_update_bh(sb, bh, sync);
brelse(bh);
ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector);
if (!ep)
return -EIO;
ep->dentry.stream.name_len = p_uniname->name_len;
ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
exfat_update_bh(sb, bh, sync);
brelse(bh);
for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
if (!ep)
return -EIO;
exfat_init_name_entry(ep, uniname);
exfat_update_bh(sb, bh, sync);
brelse(bh);
uniname += EXFAT_FILE_NAME_LEN;
}
exfat_update_dir_chksum(inode, p_dir, entry);
return 0;
}
int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
int entry, int order, int num_entries)
{
struct super_block *sb = inode->i_sb;
int i;
sector_t sector;
struct exfat_dentry *ep;
struct buffer_head *bh;
for (i = order; i < num_entries; i++) {
ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, &sector);
if (!ep)
return -EIO;
exfat_set_entry_type(ep, TYPE_DELETED);
exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
brelse(bh);
}
return 0;
}
void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
{
int chksum_type = CS_DIR_ENTRY, i;
unsigned short chksum = 0;
struct exfat_dentry *ep;
for (i = 0; i < es->num_entries; i++) {
ep = exfat_get_dentry_cached(es, i);
chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
chksum_type);
chksum_type = CS_DEFAULT;
}
ep = exfat_get_dentry_cached(es, 0);
ep->dentry.file.checksum = cpu_to_le16(chksum);
es->modified = true;
}
void exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
{
int i;
for (i = 0; i < es->num_bh; i++) {
if (es->modified)
exfat_update_bh(es->sb, es->bh[i], sync);
brelse(es->bh[i]);
}
kfree(es);
}
static int exfat_walk_fat_chain(struct super_block *sb,
struct exfat_chain *p_dir, unsigned int byte_offset,
unsigned int *clu)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
unsigned int clu_offset;
unsigned int cur_clu;
clu_offset = EXFAT_B_TO_CLU(byte_offset, sbi);
cur_clu = p_dir->dir;
if (p_dir->flags == ALLOC_NO_FAT_CHAIN) {
cur_clu += clu_offset;
} else {
while (clu_offset > 0) {
if (exfat_get_next_cluster(sb, &cur_clu))
return -EIO;
if (cur_clu == EXFAT_EOF_CLUSTER) {
exfat_fs_error(sb,
"invalid dentry access beyond EOF (clu : %u, eidx : %d)",
p_dir->dir,
EXFAT_B_TO_DEN(byte_offset));
return -EIO;
}
clu_offset--;
}
}
*clu = cur_clu;
return 0;
}
int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
int entry, sector_t *sector, int *offset)
{
int ret;
unsigned int off, clu = 0;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
off = EXFAT_DEN_TO_B(entry);
ret = exfat_walk_fat_chain(sb, p_dir, off, &clu);
if (ret)
return ret;
/* byte offset in cluster */
off = EXFAT_CLU_OFFSET(off, sbi);
/* byte offset in sector */
*offset = EXFAT_BLK_OFFSET(off, sb);
/* sector offset in cluster */
*sector = EXFAT_B_TO_BLK(off, sb);
*sector += exfat_cluster_to_sector(sbi, clu);
return 0;
}
#define EXFAT_MAX_RA_SIZE (128*1024)
static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct buffer_head *bh;
unsigned int max_ra_count = EXFAT_MAX_RA_SIZE >> sb->s_blocksize_bits;
unsigned int page_ra_count = PAGE_SIZE >> sb->s_blocksize_bits;
unsigned int adj_ra_count = max(sbi->sect_per_clus, page_ra_count);
unsigned int ra_count = min(adj_ra_count, max_ra_count);
/* Read-ahead is not required */
if (sbi->sect_per_clus == 1)
return 0;
if (sec < sbi->data_start_sector) {
exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
(unsigned long long)sec, sbi->data_start_sector);
return -EIO;
}
/* Not sector aligned with ra_count, resize ra_count to page size */
if ((sec - sbi->data_start_sector) & (ra_count - 1))
ra_count = page_ra_count;
bh = sb_find_get_block(sb, sec);
if (!bh || !buffer_uptodate(bh)) {
unsigned int i;
for (i = 0; i < ra_count; i++)
sb_breadahead(sb, (sector_t)(sec + i));
}
brelse(bh);
return 0;
}
struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
sector_t *sector)
{
unsigned int dentries_per_page = EXFAT_B_TO_DEN(PAGE_SIZE);
int off;
sector_t sec;
if (p_dir->dir == DIR_DELETED) {
exfat_err(sb, "abnormal access to deleted dentry");
return NULL;
}
if (exfat_find_location(sb, p_dir, entry, &sec, &off))
return NULL;
if (p_dir->dir != EXFAT_FREE_CLUSTER &&
!(entry & (dentries_per_page - 1)))
exfat_dir_readahead(sb, sec);
*bh = sb_bread(sb, sec);
if (!*bh)
return NULL;
if (sector)
*sector = sec;
return (struct exfat_dentry *)((*bh)->b_data + off);
}
enum exfat_validate_dentry_mode {
ES_MODE_STARTED,
ES_MODE_GET_FILE_ENTRY,
ES_MODE_GET_STRM_ENTRY,
ES_MODE_GET_NAME_ENTRY,
ES_MODE_GET_CRITICAL_SEC_ENTRY,
};
static bool exfat_validate_entry(unsigned int type,
enum exfat_validate_dentry_mode *mode)
{
if (type == TYPE_UNUSED || type == TYPE_DELETED)
return false;
switch (*mode) {
case ES_MODE_STARTED:
if (type != TYPE_FILE && type != TYPE_DIR)
return false;
*mode = ES_MODE_GET_FILE_ENTRY;
return true;
case ES_MODE_GET_FILE_ENTRY:
if (type != TYPE_STREAM)
return false;
*mode = ES_MODE_GET_STRM_ENTRY;
return true;
case ES_MODE_GET_STRM_ENTRY:
if (type != TYPE_EXTEND)
return false;
*mode = ES_MODE_GET_NAME_ENTRY;
return true;
case ES_MODE_GET_NAME_ENTRY:
if (type == TYPE_STREAM)
return false;
if (type != TYPE_EXTEND) {
if (!(type & TYPE_CRITICAL_SEC))
return false;
*mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
}
return true;
case ES_MODE_GET_CRITICAL_SEC_ENTRY:
if (type == TYPE_EXTEND || type == TYPE_STREAM)
return false;
if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
return false;
return true;
default:
WARN_ON_ONCE(1);
return false;
}
}
struct exfat_dentry *exfat_get_dentry_cached(
struct exfat_entry_set_cache *es, int num)
{
int off = es->start_off + num * DENTRY_SIZE;
struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
return (struct exfat_dentry *)p;
}
/*
* Returns a set of dentries for a file or dir.
*
* Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
* User should call exfat_get_dentry_set() after setting 'modified' to apply
* changes made in this entry set to the real device.
*
* in:
* sb+p_dir+entry: indicates a file/dir
* type: specifies how many dentries should be included.
* return:
* pointer of entry set on success,
* NULL on failure.
*/
struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
struct exfat_chain *p_dir, int entry, unsigned int type)
{
int ret, i, num_bh;
unsigned int off, byte_offset, clu = 0;
sector_t sec;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_entry_set_cache *es;
struct exfat_dentry *ep;
int num_entries;
enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
struct buffer_head *bh;
if (p_dir->dir == DIR_DELETED) {
exfat_err(sb, "access to deleted dentry");
return NULL;
}
byte_offset = EXFAT_DEN_TO_B(entry);
ret = exfat_walk_fat_chain(sb, p_dir, byte_offset, &clu);
if (ret)
return NULL;
es = kzalloc(sizeof(*es), GFP_KERNEL);
if (!es)
return NULL;
es->sb = sb;
es->modified = false;
/* byte offset in cluster */
byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
/* byte offset in sector */
off = EXFAT_BLK_OFFSET(byte_offset, sb);
es->start_off = off;
/* sector offset in cluster */
sec = EXFAT_B_TO_BLK(byte_offset, sb);
sec += exfat_cluster_to_sector(sbi, clu);
bh = sb_bread(sb, sec);
if (!bh)
goto free_es;
es->bh[es->num_bh++] = bh;
ep = exfat_get_dentry_cached(es, 0);
if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
goto free_es;
num_entries = type == ES_ALL_ENTRIES ?
ep->dentry.file.num_ext + 1 : type;
es->num_entries = num_entries;
num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
for (i = 1; i < num_bh; i++) {
/* get the next sector */
if (exfat_is_last_sector_in_cluster(sbi, sec)) {
if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
clu++;
else if (exfat_get_next_cluster(sb, &clu))
goto free_es;
sec = exfat_cluster_to_sector(sbi, clu);
} else {
sec++;
}
bh = sb_bread(sb, sec);
if (!bh)
goto free_es;
es->bh[es->num_bh++] = bh;
}
/* validiate cached dentries */
for (i = 1; i < num_entries; i++) {
ep = exfat_get_dentry_cached(es, i);
if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
goto free_es;
}
return es;
free_es:
exfat_free_dentry_set(es, false);
return NULL;
}
enum {
DIRENT_STEP_FILE,
DIRENT_STEP_STRM,
DIRENT_STEP_NAME,
DIRENT_STEP_SECD,
};
/*
* return values:
* >= 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
*/
int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
int num_entries, unsigned int type)
{
int i, rewind = 0, dentry = 0, end_eidx = 0, num_ext = 0, len;
int order, step, name_len = 0;
int dentries_per_clu, num_empty = 0;
unsigned int entry_type;
unsigned short *uniname = NULL;
struct exfat_chain clu;
struct exfat_hint *hint_stat = &ei->hint_stat;
struct exfat_hint_femp candi_empty;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
dentries_per_clu = sbi->dentries_per_clu;
exfat_chain_dup(&clu, p_dir);
if (hint_stat->eidx) {
clu.dir = hint_stat->clu;
dentry = hint_stat->eidx;
end_eidx = dentry;
}
candi_empty.eidx = EXFAT_HINT_NONE;
rewind:
order = 0;
step = DIRENT_STEP_FILE;
while (clu.dir != EXFAT_EOF_CLUSTER) {
i = dentry & (dentries_per_clu - 1);
for (; i < dentries_per_clu; i++, dentry++) {
struct exfat_dentry *ep;
struct buffer_head *bh;
if (rewind && dentry == end_eidx)
goto not_found;
ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
if (!ep)
return -EIO;
entry_type = exfat_get_entry_type(ep);
if (entry_type == TYPE_UNUSED ||
entry_type == TYPE_DELETED) {
step = DIRENT_STEP_FILE;
num_empty++;
if (candi_empty.eidx == EXFAT_HINT_NONE &&
num_empty == 1) {
exfat_chain_set(&candi_empty.cur,
clu.dir, clu.size, clu.flags);
}
if (candi_empty.eidx == EXFAT_HINT_NONE &&
num_empty >= num_entries) {
candi_empty.eidx =
dentry - (num_empty - 1);
WARN_ON(candi_empty.eidx < 0);
candi_empty.count = num_empty;
if (ei->hint_femp.eidx ==
EXFAT_HINT_NONE ||
candi_empty.eidx <=
ei->hint_femp.eidx) {
memcpy(&ei->hint_femp,
&candi_empty,
sizeof(candi_empty));
}
}
brelse(bh);
if (entry_type == TYPE_UNUSED)
goto not_found;
continue;
}
num_empty = 0;
candi_empty.eidx = EXFAT_HINT_NONE;
if (entry_type == TYPE_FILE || entry_type == TYPE_DIR) {
step = DIRENT_STEP_FILE;
if (type == TYPE_ALL || type == entry_type) {
num_ext = ep->dentry.file.num_ext;
step = DIRENT_STEP_STRM;
}
brelse(bh);
continue;
}
if (entry_type == TYPE_STREAM) {
u16 name_hash;
if (step != DIRENT_STEP_STRM) {
step = DIRENT_STEP_FILE;
brelse(bh);
continue;
}
step = DIRENT_STEP_FILE;
name_hash = le16_to_cpu(
ep->dentry.stream.name_hash);
if (p_uniname->name_hash == name_hash &&
p_uniname->name_len ==
ep->dentry.stream.name_len) {
step = DIRENT_STEP_NAME;
order = 1;
name_len = 0;
}
brelse(bh);
continue;
}
brelse(bh);
if (entry_type == TYPE_EXTEND) {
unsigned short entry_uniname[16], unichar;
if (step != DIRENT_STEP_NAME) {
step = DIRENT_STEP_FILE;
continue;
}
if (++order == 2)
uniname = p_uniname->name;
else
uniname += EXFAT_FILE_NAME_LEN;
len = exfat_extract_uni_name(ep, entry_uniname);
name_len += len;
unichar = *(uniname+len);
*(uniname+len) = 0x0;
if (exfat_uniname_ncmp(sb, uniname,
entry_uniname, len)) {
step = DIRENT_STEP_FILE;
} else if (p_uniname->name_len == name_len) {
if (order == num_ext)
goto found;
step = DIRENT_STEP_SECD;
}
*(uniname+len) = unichar;
continue;
}
if (entry_type &
(TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)) {
if (step == DIRENT_STEP_SECD) {
if (++order == num_ext)
goto found;
continue;
}
}
step = DIRENT_STEP_FILE;
}
if (clu.flags == ALLOC_NO_FAT_CHAIN) {
if (--clu.size > 0)
clu.dir++;
else
clu.dir = EXFAT_EOF_CLUSTER;
} else {
if (exfat_get_next_cluster(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 empty hint */
num_empty = 0;
candi_empty.eidx = EXFAT_HINT_NONE;
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 - 1))) {
int ret = 0;
if (clu.flags == ALLOC_NO_FAT_CHAIN) {
if (--clu.size > 0)
clu.dir++;
else
clu.dir = EXFAT_EOF_CLUSTER;
} else {
ret = exfat_get_next_cluster(sb, &clu.dir);
}
if (ret || clu.dir != EXFAT_EOF_CLUSTER) {
/* just initialized hint_stat */
hint_stat->clu = p_dir->dir;
hint_stat->eidx = 0;
return (dentry - num_ext);
}
}
hint_stat->clu = clu.dir;
hint_stat->eidx = dentry + 1;
return dentry - num_ext;
}
int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
int entry, struct exfat_dentry *ep)
{
int i, count = 0;
unsigned int type;
struct exfat_dentry *ext_ep;
struct buffer_head *bh;
for (i = 0, entry++; i < ep->dentry.file.num_ext; i++, entry++) {
ext_ep = exfat_get_dentry(sb, p_dir, entry, &bh, NULL);
if (!ext_ep)
return -EIO;
type = exfat_get_entry_type(ext_ep);
brelse(bh);
if (type == TYPE_EXTEND || type == TYPE_STREAM)
count++;
else
break;
}
return count;
}
int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
{
int i, count = 0;
int dentries_per_clu;
unsigned int entry_type;
struct exfat_chain clu;
struct exfat_dentry *ep;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct buffer_head *bh;
dentries_per_clu = sbi->dentries_per_clu;
exfat_chain_dup(&clu, p_dir);
while (clu.dir != EXFAT_EOF_CLUSTER) {
for (i = 0; i < dentries_per_clu; i++) {
ep = exfat_get_dentry(sb, &clu, i, &bh, NULL);
if (!ep)
return -EIO;
entry_type = exfat_get_entry_type(ep);
brelse(bh);
if (entry_type == TYPE_UNUSED)
return count;
if (entry_type != TYPE_DIR)
continue;
count++;
}
if (clu.flags == ALLOC_NO_FAT_CHAIN) {
if (--clu.size > 0)
clu.dir++;
else
clu.dir = EXFAT_EOF_CLUSTER;
} else {
if (exfat_get_next_cluster(sb, &(clu.dir)))
return -EIO;
}
}
return count;
}
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