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linux/fs/exfat/super.c
Linus Torvalds 511fb5bafe v6.6-vfs.super 
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Merge tag 'v6.6-vfs.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull superblock updates from Christian Brauner:
 "This contains the super rework that was ready for this cycle. The
  first part changes the order of how we open block devices and allocate
  superblocks, contains various cleanups, simplifications, and a new
  mechanism to wait on superblock state changes.

  This unblocks work to ultimately limit the number of writers to a
  block device. Jan has already scheduled follow-up work that will be
  ready for v6.7 and allows us to restrict the number of writers to a
  given block device. That series builds on this work right here.

  The second part contains filesystem freezing updates.

  Overview:

  The generic superblock changes are rougly organized as follows
  (ignoring additional minor cleanups):

   (1) Removal of the bd_super member from struct block_device.

       This was a very odd back pointer to struct super_block with
       unclear rules. For all relevant places we have other means to get
       the same information so just get rid of this.

   (2) Simplify rules for superblock cleanup.

       Roughly, everything that is allocated during fs_context
       initialization and that's stored in fs_context->s_fs_info needs
       to be cleaned up by the fs_context->free() implementation before
       the superblock allocation function has been called successfully.

       After sget_fc() returned fs_context->s_fs_info has been
       transferred to sb->s_fs_info at which point sb->kill_sb() if
       fully responsible for cleanup. Adhering to these rules means that
       cleanup of sb->s_fs_info in fill_super() is to be avoided as it's
       brittle and inconsistent.

       Cleanup shouldn't be duplicated between sb->put_super() as
       sb->put_super() is only called if sb->s_root has been set aka
       when the filesystem has been successfully born (SB_BORN). That
       complexity should be avoided.

       This also means that block devices are to be closed in
       sb->kill_sb() instead of sb->put_super(). More details in the
       lower section.

   (3) Make it possible to lookup or create a superblock before opening
       block devices

       There's a subtle dependency on (2) as some filesystems did rely
       on fill_super() to be called in order to correctly clean up
       sb->s_fs_info. All these filesystems have been fixed.

   (4) Switch most filesystem to follow the same logic as the generic
       mount code now does as outlined in (3).

   (5) Use the superblock as the holder of the block device. We can now
       easily go back from block device to owning superblock.

   (6) Export and extend the generic fs_holder_ops and use them as
       holder ops everywhere and remove the filesystem specific holder
       ops.

   (7) Call from the block layer up into the filesystem layer when the
       block device is removed, allowing to shut down the filesystem
       without risk of deadlocks.

   (8) Get rid of get_super().

       We can now easily go back from the block device to owning
       superblock and can call up from the block layer into the
       filesystem layer when the device is removed. So no need to wade
       through all registered superblock to find the owning superblock
       anymore"

Link: https://lore.kernel.org/lkml/20230824-prall-intakt-95dbffdee4a0@brauner/

* tag 'v6.6-vfs.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (47 commits)
  super: use higher-level helper for {freeze,thaw}
  super: wait until we passed kill super
  super: wait for nascent superblocks
  super: make locking naming consistent
  super: use locking helpers
  fs: simplify invalidate_inodes
  fs: remove get_super
  block: call into the file system for ioctl BLKFLSBUF
  block: call into the file system for bdev_mark_dead
  block: consolidate __invalidate_device and fsync_bdev
  block: drop the "busy inodes on changed media" log message
  dasd: also call __invalidate_device when setting the device offline
  amiflop: don't call fsync_bdev in FDFMTBEG
  floppy: call disk_force_media_change when changing the format
  block: simplify the disk_force_media_change interface
  nbd: call blk_mark_disk_dead in nbd_clear_sock_ioctl
  xfs use fs_holder_ops for the log and RT devices
  xfs: drop s_umount over opening the log and RT devices
  ext4: use fs_holder_ops for the log device
  ext4: drop s_umount over opening the log device
  ...
2023-08-28 11:04:18 -07:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*/
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#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/iversion.h>
#include <linux/nls.h>
#include <linux/buffer_head.h>
#include <linux/magic.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
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_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);
unload_nls(sbi->nls_io);
exfat_free_upcase_table(sbi);
}
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 = u64_to_fsid(id);
/* 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;
/* 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 (sb_rdonly(sb))
return 0;
p_boot->vol_flags = cpu_to_le16(new_flags);
set_buffer_uptodate(sbi->boot_bh);
mark_buffer_dirty(sbi->boot_bh);
__sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
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->keep_last_dots)
seq_puts(m, ",keep_last_dots");
if (opts->sys_tz)
seq_puts(m, ",sys_tz");
else 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 = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
init_rwsem(&ei->truncate_lock);
return &ei->vfs_inode;
}
static void exfat_free_inode(struct inode *inode)
{
kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
}
static const struct super_operations exfat_sops = {
.alloc_inode = exfat_alloc_inode,
.free_inode = exfat_free_inode,
.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,
};
enum {
Opt_uid,
Opt_gid,
Opt_umask,
Opt_dmask,
Opt_fmask,
Opt_allow_utime,
Opt_charset,
Opt_errors,
Opt_discard,
Opt_keep_last_dots,
Opt_sys_tz,
Opt_time_offset,
/* Deprecated options */
Opt_utf8,
Opt_debug,
Opt_namecase,
Opt_codepage,
};
static const struct constant_table exfat_param_enums[] = {
{ "continue", EXFAT_ERRORS_CONT },
{ "panic", EXFAT_ERRORS_PANIC },
{ "remount-ro", EXFAT_ERRORS_RO },
{}
};
static const struct fs_parameter_spec exfat_parameters[] = {
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),
fsparam_enum("errors", Opt_errors, exfat_param_enums),
fsparam_flag("discard", Opt_discard),
fsparam_flag("keep_last_dots", Opt_keep_last_dots),
fsparam_flag("sys_tz", Opt_sys_tz),
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),
{}
};
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;
opt = fs_parse(fc, exfat_parameters, param, &result);
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_keep_last_dots:
opts->keep_last_dots = 1;
break;
case Opt_sys_tz:
opts->sys_tz = 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;
}
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;
inode_inc_iversion(inode);
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 = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
ei->i_size_aligned = i_size_read(inode);
ei->i_size_ondisk = i_size_read(inode);
exfat_save_attr(inode, ATTR_SUBDIR);
inode->i_mtime = inode->i_atime = ei->i_crtime = inode_set_ctime_current(inode);
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)) {
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;
}
/*
* sect_size_bits could be at least 9 and at most 12.
*/
if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
exfat_err(sb, "bogus sector size bits : %u",
p_boot->sect_size_bits);
return -EINVAL;
}
/*
* sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
*/
if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
exfat_err(sb, "bogus sectors bits per cluster : %u",
p_boot->sect_per_clus_bits);
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 ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
(u64)sbi->num_clusters * 4) {
exfat_err(sb, "bogus fat length");
return -EINVAL;
}
if (sbi->data_start_sector <
(u64)sbi->FAT1_start_sector +
(u64)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;
}
static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct exfat_sb_info *sbi = sb->s_fs_info;
struct exfat_mount_options *opts = &sbi->options;
struct inode *root_inode;
int err;
if (opts->allow_utime == (unsigned short)-1)
opts->allow_utime = ~opts->fs_dmask & 0022;
if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
opts->discard = 0;
}
sb->s_flags |= SB_NODIRATIME;
sb->s_magic = EXFAT_SUPER_MAGIC;
sb->s_op = &exfat_sops;
sb->s_time_gran = 10 * NSEC_PER_MSEC;
sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
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"))
opts->utf8 = 1;
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;
inode_set_iversion(root_inode, 1);
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 free_table;
}
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);
return err;
}
static int exfat_get_tree(struct fs_context *fc)
{
return get_tree_bdev(fc, exfat_fill_super);
}
static void exfat_free_sbi(struct exfat_sb_info *sbi)
{
exfat_free_iocharset(sbi);
kfree(sbi);
}
static void exfat_free(struct fs_context *fc)
{
struct exfat_sb_info *sbi = fc->s_fs_info;
if (sbi)
exfat_free_sbi(sbi);
}
static int exfat_reconfigure(struct fs_context *fc)
{
fc->sb_flags |= SB_NODIRATIME;
/* volume flag will be updated in exfat_sync_fs */
sync_filesystem(fc->root->d_sb);
return 0;
}
static const struct fs_context_operations exfat_context_ops = {
.parse_param = exfat_parse_param,
.get_tree = exfat_get_tree,
.free = exfat_free,
.reconfigure = exfat_reconfigure,
};
static int exfat_init_fs_context(struct fs_context *fc)
{
struct exfat_sb_info *sbi;
sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
mutex_init(&sbi->s_lock);
mutex_init(&sbi->bitmap_lock);
ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
sbi->options.fs_uid = current_uid();
sbi->options.fs_gid = current_gid();
sbi->options.fs_fmask = current->fs->umask;
sbi->options.fs_dmask = current->fs->umask;
sbi->options.allow_utime = -1;
sbi->options.iocharset = exfat_default_iocharset;
sbi->options.errors = EXFAT_ERRORS_RO;
fc->s_fs_info = sbi;
fc->ops = &exfat_context_ops;
return 0;
}
static void exfat_kill_sb(struct super_block *sb)
{
struct exfat_sb_info *sbi = sb->s_fs_info;
kill_block_super(sb);
if (sbi)
exfat_free_sbi(sbi);
}
static struct file_system_type exfat_fs_type = {
.owner = THIS_MODULE,
.name = "exfat",
.init_fs_context = exfat_init_fs_context,
.parameters = exfat_parameters,
.kill_sb = exfat_kill_sb,
.fs_flags = FS_REQUIRES_DEV,
};
static void exfat_inode_init_once(void *foo)
{
struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
spin_lock_init(&ei->cache_lru_lock);
ei->nr_caches = 0;
ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
INIT_LIST_HEAD(&ei->cache_lru);
INIT_HLIST_NODE(&ei->i_hash_fat);
inode_init_once(&ei->vfs_inode);
}
static int __init init_exfat_fs(void)
{
int err;
err = exfat_cache_init();
if (err)
return err;
exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
sizeof(struct exfat_inode_info),
0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
exfat_inode_init_once);
if (!exfat_inode_cachep) {
err = -ENOMEM;
goto shutdown_cache;
}
err = register_filesystem(&exfat_fs_type);
if (err)
goto destroy_cache;
return 0;
destroy_cache:
kmem_cache_destroy(exfat_inode_cachep);
shutdown_cache:
exfat_cache_shutdown();
return err;
}
static void __exit exit_exfat_fs(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(exfat_inode_cachep);
unregister_filesystem(&exfat_fs_type);
exfat_cache_shutdown();
}
module_init(init_exfat_fs);
module_exit(exit_exfat_fs);
MODULE_ALIAS_FS("exfat");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("exFAT filesystem support");
MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
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