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super.c
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super.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*/
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#else
#include <linux/cred.h>
#include <linux/parser.h>
#endif
#include <linux/module.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/mount.h>
#include <linux/cred.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/blkdev.h>
#include <linux/fs_struct.h>
#include <linux/nls.h>
#include <linux/buffer_head.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0)
#include <linux/iversion.h>
#endif
#include "exfat_raw.h"
#include "exfat_fs.h"
#ifndef CONFIG_EXFAT_DEFAULT_IOCHARSET /* if Kconfig lacked iocharset */
#define CONFIG_EXFAT_DEFAULT_IOCHARSET "utf8"
#endif
static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
static struct kmem_cache *exfat_inode_cachep;
static void exfat_free_iocharset(struct exfat_sb_info *sbi)
{
if (sbi->options.iocharset != exfat_default_iocharset)
kfree(sbi->options.iocharset);
}
static void exfat_delayed_free(struct rcu_head *p)
{
struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
unload_nls(sbi->nls_io);
exfat_free_iocharset(sbi);
exfat_free_upcase_table(sbi);
kfree(sbi);
}
static void exfat_put_super(struct super_block *sb)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
mutex_lock(&sbi->s_lock);
exfat_free_bitmap(sbi);
brelse(sbi->boot_bh);
mutex_unlock(&sbi->s_lock);
call_rcu(&sbi->rcu, exfat_delayed_free);
}
static int exfat_sync_fs(struct super_block *sb, int wait)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
int err = 0;
if (!wait)
return 0;
/* If there are some dirty buffers in the bdev inode */
mutex_lock(&sbi->s_lock);
sync_blockdev(sb->s_bdev);
if (exfat_clear_volume_dirty(sb))
err = -EIO;
mutex_unlock(&sbi->s_lock);
return err;
}
static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
mutex_lock(&sbi->s_lock);
if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
mutex_unlock(&sbi->s_lock);
return -EIO;
}
mutex_unlock(&sbi->s_lock);
}
buf->f_type = sb->s_magic;
buf->f_bsize = sbi->cluster_size;
buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
buf->f_bfree = buf->f_blocks - sbi->used_clusters;
buf->f_bavail = buf->f_bfree;
buf->f_fsid.val[0] = (unsigned int)id;
buf->f_fsid.val[1] = (unsigned int)(id >> 32);
/* Unicode utf16 255 characters */
buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
return 0;
}
static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
bool sync;
/* retain persistent-flags */
new_flags |= sbi->vol_flags_persistent;
/* flags are not changed */
if (sbi->vol_flags == new_flags)
return 0;
sbi->vol_flags = new_flags;
/* skip updating volume dirty flag,
* if this volume has been mounted with read-only
*/
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0)
if (sb_rdonly(sb))
#else
if (sb->s_flags & MS_RDONLY)
#endif
return 0;
p_boot->vol_flags = cpu_to_le16(new_flags);
if ((new_flags & VOLUME_DIRTY) && !buffer_dirty(sbi->boot_bh))
sync = true;
else
sync = false;
set_buffer_uptodate(sbi->boot_bh);
mark_buffer_dirty(sbi->boot_bh);
if (sync)
sync_dirty_buffer(sbi->boot_bh);
return 0;
}
int exfat_set_volume_dirty(struct super_block *sb)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
}
int exfat_clear_volume_dirty(struct super_block *sb)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
}
static int exfat_show_options(struct seq_file *m, struct dentry *root)
{
struct super_block *sb = root->d_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_mount_options *opts = &sbi->options;
/* Show partition info */
if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
seq_printf(m, ",uid=%u",
from_kuid_munged(&init_user_ns, opts->fs_uid));
if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
seq_printf(m, ",gid=%u",
from_kgid_munged(&init_user_ns, opts->fs_gid));
seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
if (opts->allow_utime)
seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
if (opts->utf8)
seq_puts(m, ",iocharset=utf8");
else if (sbi->nls_io)
seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
if (opts->errors == EXFAT_ERRORS_CONT)
seq_puts(m, ",errors=continue");
else if (opts->errors == EXFAT_ERRORS_PANIC)
seq_puts(m, ",errors=panic");
else
seq_puts(m, ",errors=remount-ro");
if (opts->discard)
seq_puts(m, ",discard");
if (opts->time_offset)
seq_printf(m, ",time_offset=%d", opts->time_offset);
return 0;
}
static struct inode *exfat_alloc_inode(struct super_block *sb)
{
struct exfat_inode_info *ei;
ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
init_rwsem(&ei->truncate_lock);
return &ei->vfs_inode;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 4, 0)
static void exfat_free_inode(struct inode *inode)
{
kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
}
#else
static void exfat_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
}
static void exfat_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, exfat_i_callback);
}
static int exfat_remount(struct super_block *sb, int *flags, char *data)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0)
*flags |= SB_NODIRATIME;
#else
*flags |= MS_NODIRATIME;
#endif
sync_filesystem(sb);
return 0;
}
#endif
static const struct super_operations exfat_sops = {
.alloc_inode = exfat_alloc_inode,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 4, 0)
.free_inode = exfat_free_inode,
#else
.destroy_inode = exfat_destroy_inode,
.remount_fs = exfat_remount,
#endif
.write_inode = exfat_write_inode,
.evict_inode = exfat_evict_inode,
.put_super = exfat_put_super,
.sync_fs = exfat_sync_fs,
.statfs = exfat_statfs,
.show_options = exfat_show_options,
};
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
enum {
Opt_uid,
Opt_gid,
Opt_umask,
Opt_dmask,
Opt_fmask,
Opt_allow_utime,
Opt_charset,
Opt_errors,
Opt_discard,
Opt_time_offset,
/* Deprecated options */
Opt_utf8,
Opt_debug,
Opt_namecase,
Opt_codepage,
};
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
static const struct constant_table exfat_param_enums[] = {
{ "continue", EXFAT_ERRORS_CONT },
{ "panic", EXFAT_ERRORS_PANIC },
{ "remount-ro", EXFAT_ERRORS_RO },
{}
};
#else
static const struct fs_parameter_enum exfat_param_enums[] = {
{ Opt_errors, "continue", EXFAT_ERRORS_CONT },
{ Opt_errors, "panic", EXFAT_ERRORS_PANIC },
{ Opt_errors, "remount-ro", EXFAT_ERRORS_RO },
{}
};
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
static const struct fs_parameter_spec exfat_parameters[] = {
#else
static const struct fs_parameter_spec exfat_param_specs[] = {
#endif
fsparam_u32("uid", Opt_uid),
fsparam_u32("gid", Opt_gid),
fsparam_u32oct("umask", Opt_umask),
fsparam_u32oct("dmask", Opt_dmask),
fsparam_u32oct("fmask", Opt_fmask),
fsparam_u32oct("allow_utime", Opt_allow_utime),
fsparam_string("iocharset", Opt_charset),
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
fsparam_enum("errors", Opt_errors, exfat_param_enums),
#else
fsparam_enum("errors", Opt_errors),
#endif
fsparam_flag("discard", Opt_discard),
fsparam_s32("time_offset", Opt_time_offset),
__fsparam(NULL, "utf8", Opt_utf8, fs_param_deprecated,
NULL),
__fsparam(NULL, "debug", Opt_debug, fs_param_deprecated,
NULL),
__fsparam(fs_param_is_u32, "namecase", Opt_namecase,
fs_param_deprecated, NULL),
__fsparam(fs_param_is_u32, "codepage", Opt_codepage,
fs_param_deprecated, NULL),
{}
};
#if LINUX_VERSION_CODE <= KERNEL_VERSION(5, 6, 0)
static const struct fs_parameter_description exfat_parameters = {
.name = "exfat",
.specs = exfat_param_specs,
.enums = exfat_param_enums,
};
#endif
static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct exfat_sb_info *sbi = fc->s_fs_info;
struct exfat_mount_options *opts = &sbi->options;
struct fs_parse_result result;
int opt;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
opt = fs_parse(fc, exfat_parameters, param, &result);
#else
opt = fs_parse(fc, &exfat_parameters, param, &result);
#endif
if (opt < 0)
return opt;
switch (opt) {
case Opt_uid:
opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
break;
case Opt_gid:
opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
break;
case Opt_umask:
opts->fs_fmask = result.uint_32;
opts->fs_dmask = result.uint_32;
break;
case Opt_dmask:
opts->fs_dmask = result.uint_32;
break;
case Opt_fmask:
opts->fs_fmask = result.uint_32;
break;
case Opt_allow_utime:
opts->allow_utime = result.uint_32 & 0022;
break;
case Opt_charset:
exfat_free_iocharset(sbi);
opts->iocharset = param->string;
param->string = NULL;
break;
case Opt_errors:
opts->errors = result.uint_32;
break;
case Opt_discard:
opts->discard = 1;
break;
case Opt_time_offset:
/*
* Make the limit 24 just in case someone invents something
* unusual.
*/
if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
return -EINVAL;
opts->time_offset = result.int_32;
break;
case Opt_utf8:
case Opt_debug:
case Opt_namecase:
case Opt_codepage:
break;
default:
return -EINVAL;
}
return 0;
}
#else
enum {
Opt_uid,
Opt_gid,
Opt_umask,
Opt_dmask,
Opt_fmask,
Opt_allow_utime,
Opt_charset,
Opt_err_cont,
Opt_err_panic,
Opt_err_ro,
Opt_err,
Opt_discard,
Opt_time_offset,
/* Deprecated options */
Opt_utf8,
Opt_debug,
Opt_namecase,
Opt_codepage,
Opt_fs,
};
static const match_table_t exfat_tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_dmask, "dmask=%o"},
{Opt_fmask, "fmask=%o"},
{Opt_allow_utime, "allow_utime=%o"},
{Opt_charset, "iocharset=%s"},
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_discard, "discard"},
{Opt_codepage, "codepage=%u"},
{Opt_namecase, "namecase=%u"},
{Opt_debug, "debug"},
{Opt_utf8, "utf8"},
{Opt_err, NULL}
};
static int parse_options(struct super_block *sb, char *options, int silent,
struct exfat_mount_options *opts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
char *tmpstr;
opts->fs_uid = current_uid();
opts->fs_gid = current_gid();
opts->fs_fmask = opts->fs_dmask = current->fs->umask;
opts->allow_utime = -1;
opts->iocharset = exfat_default_iocharset;
opts->utf8 = 0;
opts->errors = EXFAT_ERRORS_RO;
opts->discard = 0;
if (!options)
goto out;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, exfat_tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
return 0;
opts->fs_uid = make_kuid(current_user_ns(), option);
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
opts->fs_gid = make_kgid(current_user_ns(), option);
break;
case Opt_umask:
case Opt_dmask:
case Opt_fmask:
if (match_octal(&args[0], &option))
return 0;
if (token != Opt_dmask)
opts->fs_fmask = option;
if (token != Opt_fmask)
opts->fs_dmask = option;
break;
case Opt_allow_utime:
if (match_octal(&args[0], &option))
return 0;
opts->allow_utime = option & (0022);
break;
case Opt_charset:
if (opts->iocharset != exfat_default_iocharset)
kfree(opts->iocharset);
tmpstr = match_strdup(&args[0]);
if (!tmpstr)
return -ENOMEM;
opts->iocharset = tmpstr;
break;
case Opt_err_cont:
opts->errors = EXFAT_ERRORS_CONT;
break;
case Opt_err_panic:
opts->errors = EXFAT_ERRORS_PANIC;
break;
case Opt_err_ro:
opts->errors = EXFAT_ERRORS_RO;
break;
case Opt_discard:
opts->discard = 1;
break;
case Opt_time_offset:
if (match_int(&args[0], &option))
return -EINVAL;
/*
* Make the limit 24 just in case someone
* invents something unusual.
*/
if (option < -24 * 60 || option > 24 * 60)
return -EINVAL;
opts->time_offset = option;
break;
case Opt_utf8:
case Opt_debug:
case Opt_namecase:
case Opt_codepage:
break;
default:
if (!silent) {
exfat_msg(sb, KERN_ERR,
"unrecognized mount option \"%s\" or missing value",
p);
}
return -EINVAL;
}
}
out:
if (opts->allow_utime == -1)
opts->allow_utime = ~opts->fs_dmask & (0022);
if (opts->discard) {
struct request_queue *q = bdev_get_queue(sb->s_bdev);
if (!blk_queue_discard(q))
exfat_msg(sb, KERN_WARNING,
"mounting with \"discard\" option, but the device does not support discard");
opts->discard = 0;
}
return 0;
}
#endif
static void exfat_hash_init(struct super_block *sb)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
int i;
spin_lock_init(&sbi->inode_hash_lock);
for (i = 0; i < EXFAT_HASH_SIZE; i++)
INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
}
static int exfat_read_root(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_inode_info *ei = EXFAT_I(inode);
struct exfat_chain cdir;
int num_subdirs, num_clu = 0;
exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
ei->entry = -1;
ei->start_clu = sbi->root_dir;
ei->flags = ALLOC_FAT_CHAIN;
ei->type = TYPE_DIR;
ei->version = 0;
ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
ei->hint_stat.eidx = 0;
ei->hint_stat.clu = sbi->root_dir;
ei->hint_femp.eidx = EXFAT_HINT_NONE;
exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
if (exfat_count_num_clusters(sb, &cdir, &num_clu))
return -EIO;
i_size_write(inode, num_clu << sbi->cluster_size_bits);
num_subdirs = exfat_count_dir_entries(sb, &cdir);
if (num_subdirs < 0)
return -EIO;
set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
inode->i_uid = sbi->options.fs_uid;
inode->i_gid = sbi->options.fs_gid;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0)
inode_inc_iversion(inode);
#else
inode->i_version++;
#endif
inode->i_generation = 0;
inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
inode->i_op = &exfat_dir_inode_operations;
inode->i_fop = &exfat_dir_operations;
inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
exfat_save_attr(inode, ATTR_SUBDIR);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0)
inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
current_time(inode);
#else
inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
CURRENT_TIME_SEC;
#endif
exfat_truncate_atime(&inode->i_atime);
return 0;
}
static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
{
struct exfat_sb_info *sbi = EXFAT_SB(sb);
if (!is_power_of_2(logical_sect) ||
logical_sect < 512 || logical_sect > 4096) {
exfat_err(sb, "bogus logical sector size %u", logical_sect);
return -EIO;
}
if (logical_sect < sb->s_blocksize) {
exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
logical_sect);
return -EIO;
}
if (logical_sect > sb->s_blocksize) {
brelse(sbi->boot_bh);
sbi->boot_bh = NULL;
if (!sb_set_blocksize(sb, logical_sect)) {
exfat_err(sb, "unable to set blocksize %u",
logical_sect);
return -EIO;
}
sbi->boot_bh = sb_bread(sb, 0);
if (!sbi->boot_bh) {
exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
sb->s_blocksize);
return -EIO;
}
}
return 0;
}
static int exfat_read_boot_sector(struct super_block *sb)
{
struct boot_sector *p_boot;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
/* set block size to read super block */
sb_min_blocksize(sb, 512);
/* read boot sector */
sbi->boot_bh = sb_bread(sb, 0);
if (!sbi->boot_bh) {
exfat_err(sb, "unable to read boot sector");
return -EIO;
}
p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
/* check the validity of BOOT */
if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
exfat_err(sb, "invalid boot record signature");
return -EINVAL;
}
if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
return -EINVAL;
}
/*
* must_be_zero field must be filled with zero to prevent mounting
* from FAT volume.
*/
if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
return -EINVAL;
if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
exfat_err(sb, "bogus number of FAT structure");
return -EINVAL;
}
sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
p_boot->sect_size_bits;
sbi->cluster_size = 1 << sbi->cluster_size_bits;
sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
if (p_boot->num_fats == 2)
sbi->FAT2_start_sector += sbi->num_FAT_sectors;
sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
/* because the cluster index starts with 2 */
sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
EXFAT_RESERVED_CLUSTERS;
sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
sbi->dentries_per_clu = 1 <<
(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
/* check consistencies */
if (sbi->num_FAT_sectors << p_boot->sect_size_bits <
sbi->num_clusters * 4) {
exfat_err(sb, "bogus fat length");
return -EINVAL;
}
if (sbi->data_start_sector <
sbi->FAT1_start_sector + sbi->num_FAT_sectors * p_boot->num_fats) {
exfat_err(sb, "bogus data start sector");
return -EINVAL;
}
if (sbi->vol_flags & VOLUME_DIRTY)
exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
if (sbi->vol_flags & MEDIA_FAILURE)
exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
/* exFAT file size is limited by a disk volume size */
sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
sbi->cluster_size_bits;
/* check logical sector size */
if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
return -EIO;
return 0;
}
static int exfat_verify_boot_region(struct super_block *sb)
{
struct buffer_head *bh = NULL;
u32 chksum = 0;
__le32 *p_sig, *p_chksum;
int sn, i;
/* read boot sector sub-regions */
for (sn = 0; sn < 11; sn++) {
bh = sb_bread(sb, sn);
if (!bh)
return -EIO;
if (sn != 0 && sn <= 8) {
/* extended boot sector sub-regions */
p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
sn, le32_to_cpu(*p_sig));
}
chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
brelse(bh);
}
/* boot checksum sub-regions */
bh = sb_bread(sb, sn);
if (!bh)
return -EIO;
for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
p_chksum = (__le32 *)&bh->b_data[i];
if (le32_to_cpu(*p_chksum) != chksum) {
exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
le32_to_cpu(*p_chksum), chksum);
brelse(bh);
return -EINVAL;
}
}
brelse(bh);
return 0;
}
/* mount the file system volume */
static int __exfat_fill_super(struct super_block *sb)
{
int ret;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
ret = exfat_read_boot_sector(sb);
if (ret) {
exfat_err(sb, "failed to read boot sector");
goto free_bh;
}
ret = exfat_verify_boot_region(sb);
if (ret) {
exfat_err(sb, "invalid boot region");
goto free_bh;
}
ret = exfat_create_upcase_table(sb);
if (ret) {
exfat_err(sb, "failed to load upcase table");
goto free_bh;
}
ret = exfat_load_bitmap(sb);
if (ret) {
exfat_err(sb, "failed to load alloc-bitmap");
goto free_upcase_table;
}
ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
if (ret) {
exfat_err(sb, "failed to scan clusters");
goto free_alloc_bitmap;
}
return 0;
free_alloc_bitmap:
exfat_free_bitmap(sbi);
free_upcase_table:
exfat_free_upcase_table(sbi);
free_bh:
brelse(sbi->boot_bh);
return ret;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
#else
static int exfat_fill_super(struct super_block *sb, void *data, int silent)
#endif
{
struct inode *root_inode;
int err;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
struct exfat_sb_info *sbi = sb->s_fs_info;
struct exfat_mount_options *opts = &sbi->options;
if (opts->allow_utime == (unsigned short)-1)
opts->allow_utime = ~opts->fs_dmask & 0022;
if (opts->discard) {
struct request_queue *q = bdev_get_queue(sb->s_bdev);
if (!blk_queue_discard(q)) {
exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
opts->discard = 0;
}
}
#else
struct exfat_sb_info *sbi;
/*
* GFP_KERNEL is ok here, because while we do hold the
* supeblock lock, memory pressure can't call back into
* the filesystem, since we're only just about to mount
* it and have no inodes etc active!
*/
sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
mutex_init(&sbi->s_lock);
sb->s_fs_info = sbi;
ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
err = parse_options(sb, data, silent, &sbi->options);
if (err) {
exfat_msg(sb, KERN_ERR, "failed to parse options");
goto check_nls_io;
}
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0)
sb->s_flags |= SB_NODIRATIME;
#else
sb->s_flags |= MS_NODIRATIME;
#endif
sb->s_magic = EXFAT_SUPER_MAGIC;
sb->s_op = &exfat_sops;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 4, 0)
sb->s_time_gran = 10 * NSEC_PER_MSEC;
sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
#endif
err = __exfat_fill_super(sb);
if (err) {
exfat_err(sb, "failed to recognize exfat type");
goto check_nls_io;
}
/* set up enough so that it can read an inode */
exfat_hash_init(sb);
if (!strcmp(sbi->options.iocharset, "utf8"))
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
opts->utf8 = 1;
#else
sbi->options.utf8 = 1;
#endif
else {
sbi->nls_io = load_nls(sbi->options.iocharset);
if (!sbi->nls_io) {
exfat_err(sb, "IO charset %s not found",
sbi->options.iocharset);
err = -EINVAL;
goto free_table;
}
}
if (sbi->options.utf8)
sb->s_d_op = &exfat_utf8_dentry_ops;
else
sb->s_d_op = &exfat_dentry_ops;
root_inode = new_inode(sb);
if (!root_inode) {
exfat_err(sb, "failed to allocate root inode");
err = -ENOMEM;
goto free_table;
}
root_inode->i_ino = EXFAT_ROOT_INO;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 16, 0)
inode_set_iversion(root_inode, 1);
#else
root_inode->i_version = 1;
#endif
err = exfat_read_root(root_inode);
if (err) {
exfat_err(sb, "failed to initialize root inode");
goto put_inode;
}
exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
insert_inode_hash(root_inode);
sb->s_root = d_make_root(root_inode);
if (!sb->s_root) {
exfat_err(sb, "failed to get the root dentry");
err = -ENOMEM;
goto put_inode;
}
return 0;
put_inode:
iput(root_inode);
sb->s_root = NULL;
free_table:
exfat_free_upcase_table(sbi);
exfat_free_bitmap(sbi);
brelse(sbi->boot_bh);
check_nls_io:
unload_nls(sbi->nls_io);
exfat_free_iocharset(sbi);
sb->s_fs_info = NULL;
kfree(sbi);
return err;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 6, 0)
static int exfat_get_tree(struct fs_context *fc)
{
return get_tree_bdev(fc, exfat_fill_super);
}
static void exfat_free(struct fs_context *fc)
{
struct exfat_sb_info *sbi = fc->s_fs_info;
if (sbi) {
exfat_free_iocharset(sbi);
kfree(sbi);
}
}
static int exfat_reconfigure(struct fs_context *fc)
{