// SPDX-License-Identifier: GPL-2.0
/*
 *
 * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
 *
 *
 *                 terminology
 *
 * cluster - allocation unit     - 512,1K,2K,4K,...,2M
 * vcn - virtual cluster number  - Offset inside the file in clusters.
 * vbo - virtual byte offset     - Offset inside the file in bytes.
 * lcn - logical cluster number  - 0 based cluster in clusters heap.
 * lbo - logical byte offset     - Absolute position inside volume.
 * run - maps VCN to LCN         - Stored in attributes in packed form.
 * attr - attribute segment      - std/name/data etc records inside MFT.
 * mi  - MFT inode               - One MFT record(usually 1024 bytes or 4K), consists of attributes.
 * ni  - NTFS inode              - Extends linux inode. consists of one or more mft inodes.
 * index - unit inside directory - 2K, 4K, <=page size, does not depend on cluster size.
 * resident attribute            - Attribute with content stored directly in the MFT record
 * non-resident attribute        - Attribute with content stored in clusters
 * data_size                     - Size of attribute content in bytes. Equal to inode->i_size
 * valid_size                    - Number of bytes written to the non-resident attribute
 * allocated_size                - Total size of clusters allocated for non-resident content
 * total_size                    - Actual size of allocated clusters for sparse or compressed attributes
 *                               - Constraint: valid_size <= data_size <= allocated_size
 *
 * WSL - Windows Subsystem for Linux
 * https://docs.microsoft.com/en-us/windows/wsl/file-permissions
 * It stores uid/gid/mode/dev in xattr
 *
 * ntfs allows up to 2^64 clusters per volume.
 * It means you should use 64 bits lcn to operate with ntfs.
 * Implementation of ntfs.sys uses only 32 bits lcn.
 * Default ntfs3 uses 32 bits lcn too.
 * ntfs3 built with CONFIG_NTFS3_64BIT_CLUSTER (ntfs3_64) uses 64 bits per lcn.
 *
 *
 *     ntfs limits, cluster size is 4K (2^12)
 * -----------------------------------------------------------------------------
 * | Volume size   | Clusters | ntfs.sys | ntfs3  | ntfs3_64 | mkntfs | chkdsk |
 * -----------------------------------------------------------------------------
 * | < 16T, 2^44   |  < 2^32  |  yes     |  yes   |   yes    |  yes   |  yes   |
 * | > 16T, 2^44   |  > 2^32  |  no      |  no    |   yes    |  yes   |  yes   |
 * ----------------------------------------------------------|------------------
 *
 * To mount large volumes as ntfs one should use large cluster size (up to 2M)
 * The maximum volume size in this case is 2^32 * 2^21 = 2^53 = 8P
 *
 *     ntfs limits, cluster size is 2M (2^21)
 * -----------------------------------------------------------------------------
 * | < 8P, 2^53    |  < 2^32  |  yes     |  yes   |   yes    |  yes   |  yes   |
 * | > 8P, 2^53    |  > 2^32  |  no      |  no    |   yes    |  yes   |  yes   |
 * ----------------------------------------------------------|------------------
 *
 */

#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/exportfs.h>
#include <linux/fs.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/fs_struct.h>
#include <linux/log2.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/nls.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/statfs.h>

#include "debug.h"
#include "ntfs.h"
#include "ntfs_fs.h"
#ifdef CONFIG_NTFS3_LZX_XPRESS
#include "lib/lib.h"
#endif

#ifdef CONFIG_PRINTK
/*
 * ntfs_printk - Trace warnings/notices/errors.
 *
 * Thanks Joe Perches <joe@perches.com> for implementation
 */
void ntfs_printk(const struct super_block *sb, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;
        int level;
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        /* Should we use different ratelimits for warnings/notices/errors? */
        if (!___ratelimit(&sbi->msg_ratelimit, "ntfs3"))
                return;

        va_start(args, fmt);

        level = printk_get_level(fmt);
        vaf.fmt = printk_skip_level(fmt);
        vaf.va = &args;
        printk("%c%cntfs3(%s): %pV\n", KERN_SOH_ASCII, level, sb->s_id, &vaf);

        va_end(args);
}

static char s_name_buf[512];
static atomic_t s_name_buf_cnt = ATOMIC_INIT(1); // 1 means 'free s_name_buf'.

/*
 * ntfs_inode_printk
 *
 * Print warnings/notices/errors about inode using name or inode number.
 */
void ntfs_inode_printk(struct inode *inode, const char *fmt, ...)
{
        struct super_block *sb = inode->i_sb;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        char *name;
        va_list args;
        struct va_format vaf;
        int level;

        if (!___ratelimit(&sbi->msg_ratelimit, "ntfs3"))
                return;

        /* Use static allocated buffer, if possible. */
        name = atomic_dec_and_test(&s_name_buf_cnt) ?
                       s_name_buf :
                       kmalloc(sizeof(s_name_buf), GFP_NOFS);

        if (name) {
                struct dentry *de = d_find_alias(inode);

                if (de) {
                        int len;
                        spin_lock(&de->d_lock);
                        len = snprintf(name, sizeof(s_name_buf), " \"%s\"",
                                       de->d_name.name);
                        spin_unlock(&de->d_lock);
                        if (len <= 0)
                                name[0] = 0;
                        else if (len >= sizeof(s_name_buf))
                                name[sizeof(s_name_buf) - 1] = 0;
                } else {
                        name[0] = 0;
                }
                dput(de); /* Cocci warns if placed in branch "if (de)" */
        }

        va_start(args, fmt);

        level = printk_get_level(fmt);
        vaf.fmt = printk_skip_level(fmt);
        vaf.va = &args;

        printk("%c%cntfs3(%s): ino=%lx,%s %pV\n", KERN_SOH_ASCII, level,
               sb->s_id, inode->i_ino, name ? name : "", &vaf);

        va_end(args);

        atomic_inc(&s_name_buf_cnt);
        if (name != s_name_buf)
                kfree(name);
}
#endif

/*
 * Shared memory struct.
 *
 * On-disk ntfs's upcase table is created by ntfs formatter.
 * 'upcase' table is 128K bytes of memory.
 * We should read it into memory when mounting.
 * Several ntfs volumes likely use the same 'upcase' table.
 * It is good idea to share in-memory 'upcase' table between different volumes.
 * Unfortunately winxp/vista/win7 use different upcase tables.
 */
static DEFINE_SPINLOCK(s_shared_lock);

static struct {
        void *ptr;
        u32 len;
        int cnt;
} s_shared[8];

/*
 * ntfs_set_shared
 *
 * Return:
 * * @ptr - If pointer was saved in shared memory.
 * * NULL - If pointer was not shared.
 */
void *ntfs_set_shared(void *ptr, u32 bytes)
{
        void *ret = NULL;
        int i, j = -1;

        spin_lock(&s_shared_lock);
        for (i = 0; i < ARRAY_SIZE(s_shared); i++) {
                if (!s_shared[i].cnt) {
                        j = i;
                } else if (bytes == s_shared[i].len &&
                           !memcmp(s_shared[i].ptr, ptr, bytes)) {
                        s_shared[i].cnt += 1;
                        ret = s_shared[i].ptr;
                        break;
                }
        }

        if (!ret && j != -1) {
                s_shared[j].ptr = ptr;
                s_shared[j].len = bytes;
                s_shared[j].cnt = 1;
                ret = ptr;
        }
        spin_unlock(&s_shared_lock);

        return ret;
}

/*
 * ntfs_put_shared
 *
 * Return:
 * * @ptr - If pointer is not shared anymore.
 * * NULL - If pointer is still shared.
 */
void *ntfs_put_shared(void *ptr)
{
        void *ret = ptr;
        int i;

        spin_lock(&s_shared_lock);
        for (i = 0; i < ARRAY_SIZE(s_shared); i++) {
                if (s_shared[i].cnt && s_shared[i].ptr == ptr) {
                        if (--s_shared[i].cnt)
                                ret = NULL;
                        break;
                }
        }
        spin_unlock(&s_shared_lock);

        return ret;
}

static inline void put_mount_options(struct ntfs_mount_options *options)
{
        kfree(options->nls_name);
        unload_nls(options->nls);
        kfree(options);
}

enum Opt {
        Opt_uid,
        Opt_gid,
        Opt_umask,
        Opt_dmask,
        Opt_fmask,
        Opt_immutable,
        Opt_discard,
        Opt_force,
        Opt_sparse,
        Opt_nohidden,
        Opt_hide_dot_files,
        Opt_windows_names,
        Opt_showmeta,
        Opt_acl,
        Opt_acl_bool,
        Opt_iocharset,
        Opt_prealloc,
        Opt_prealloc_bool,
        Opt_nocase,
        Opt_delalloc,
        Opt_delalloc_bool,
        Opt_err,
};

// clang-format off
static const struct fs_parameter_spec ntfs_fs_parameters[] = {
        fsparam_uid("uid",              Opt_uid),
        fsparam_gid("gid",              Opt_gid),
        fsparam_u32oct("umask",         Opt_umask),
        fsparam_u32oct("dmask",         Opt_dmask),
        fsparam_u32oct("fmask",         Opt_fmask),
        fsparam_flag("sys_immutable",   Opt_immutable),
        fsparam_flag("discard",         Opt_discard),
        fsparam_flag("force",           Opt_force),
        fsparam_flag("sparse",          Opt_sparse),
        fsparam_flag("nohidden",        Opt_nohidden),
        fsparam_flag("hide_dot_files",  Opt_hide_dot_files),
        fsparam_flag("windows_names",   Opt_windows_names),
        fsparam_flag("showmeta",        Opt_showmeta),
        fsparam_flag("acl",             Opt_acl),
        fsparam_bool("acl",             Opt_acl_bool),
        fsparam_string("iocharset",     Opt_iocharset),
        fsparam_flag("prealloc",        Opt_prealloc),
        fsparam_bool("prealloc",        Opt_prealloc_bool),
        fsparam_flag("nocase",          Opt_nocase),
        fsparam_flag("delalloc",        Opt_delalloc),
        fsparam_bool("delalloc",        Opt_delalloc_bool),
        {}
};
// clang-format on

/*
 * Load nls table or if @nls is utf8 then return NULL.
 *
 */
static struct nls_table *ntfs_load_nls(const char *nls)
{
        struct nls_table *ret;

        if (!nls)
                nls = CONFIG_NLS_DEFAULT;

        if (strcmp(nls, "utf8") == 0)
                return NULL;

        if (strcmp(nls, CONFIG_NLS_DEFAULT) == 0)
                return load_nls_default();

        ret = load_nls(nls);
        if (ret)
                return ret;

        return ERR_PTR(-EINVAL);
}

static int ntfs_fs_parse_param(struct fs_context *fc,
                               struct fs_parameter *param)
{
        struct ntfs_mount_options *opts = fc->fs_private;
        struct fs_parse_result result;
        int opt;

        opt = fs_parse(fc, ntfs_fs_parameters, param, &result);
        if (opt < 0)
                return opt;

        switch (opt) {
        case Opt_uid:
                opts->fs_uid = result.uid;
                break;
        case Opt_gid:
                opts->fs_gid = result.gid;
                break;
        case Opt_umask:
                if (result.uint_32 & ~07777)
                        return invalf(fc, "ntfs3: Invalid value for umask.");
                opts->fs_fmask_inv = ~result.uint_32;
                opts->fs_dmask_inv = ~result.uint_32;
                opts->fmask = 1;
                opts->dmask = 1;
                break;
        case Opt_dmask:
                if (result.uint_32 & ~07777)
                        return invalf(fc, "ntfs3: Invalid value for dmask.");
                opts->fs_dmask_inv = ~result.uint_32;
                opts->dmask = 1;
                break;
        case Opt_fmask:
                if (result.uint_32 & ~07777)
                        return invalf(fc, "ntfs3: Invalid value for fmask.");
                opts->fs_fmask_inv = ~result.uint_32;
                opts->fmask = 1;
                break;
        case Opt_immutable:
                opts->sys_immutable = 1;
                break;
        case Opt_discard:
                opts->discard = 1;
                break;
        case Opt_force:
                opts->force = 1;
                break;
        case Opt_sparse:
                opts->sparse = 1;
                break;
        case Opt_nohidden:
                opts->nohidden = 1;
                break;
        case Opt_hide_dot_files:
                opts->hide_dot_files = 1;
                break;
        case Opt_windows_names:
                opts->windows_names = 1;
                break;
        case Opt_showmeta:
                opts->showmeta = 1;
                break;
        case Opt_acl_bool:
                if (result.boolean) {
                        fallthrough;
                case Opt_acl:
#ifdef CONFIG_NTFS3_FS_POSIX_ACL
                        fc->sb_flags |= SB_POSIXACL;
#else
                        return invalf(
                                fc, "ntfs3: Support for ACL not compiled in!");
#endif
                } else
                        fc->sb_flags &= ~SB_POSIXACL;
                break;
        case Opt_iocharset:
                kfree(opts->nls_name);
                opts->nls_name = param->string;
                param->string = NULL;
                break;
        case Opt_prealloc:
                opts->prealloc = 1;
                break;
        case Opt_prealloc_bool:
                opts->prealloc = result.boolean;
                break;
        case Opt_nocase:
                opts->nocase = 1;
                break;
        case Opt_delalloc:
                opts->delalloc = 1;
                break;
        case Opt_delalloc_bool:
                opts->delalloc = result.boolean;
                break;
        default:
                /* Should not be here unless we forget add case. */
                return -EINVAL;
        }
        return 0;
}

static int ntfs_fs_reconfigure(struct fs_context *fc)
{
        struct super_block *sb = fc->root->d_sb;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct ntfs_mount_options *new_opts = fc->fs_private;
        int ro_rw;

        /* If ntfs3 is used as legacy ntfs enforce read-only mode. */
        if (is_legacy_ntfs(sb)) {
                fc->sb_flags |= SB_RDONLY;
                goto out;
        }

        ro_rw = sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY);
        if (ro_rw && (sbi->flags & NTFS_FLAGS_NEED_REPLAY)) {
                errorf(fc,
                       "ntfs3: Couldn't remount rw because journal is not replayed. Please umount/remount instead\n");
                return -EINVAL;
        }

        new_opts->nls = ntfs_load_nls(new_opts->nls_name);
        if (IS_ERR(new_opts->nls)) {
                new_opts->nls = NULL;
                errorf(fc, "ntfs3: Cannot load iocharset %s",
                       new_opts->nls_name);
                return -EINVAL;
        }
        if (new_opts->nls != sbi->options->nls)
                return invalf(
                        fc,
                        "ntfs3: Cannot use different iocharset when remounting!");

        if (ro_rw && (sbi->volume.flags & VOLUME_FLAG_DIRTY) &&
            !new_opts->force) {
                errorf(fc,
                       "ntfs3: Volume is dirty and \"force\" flag is not set!");
                return -EINVAL;
        }

out:
        sync_filesystem(sb);
        swap(sbi->options, fc->fs_private);

        return 0;
}

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_info_root;

/*
 * ntfs3_volinfo:
 *
 * The content of /proc/fs/ntfs3/<dev>/volinfo
 *
 * ntfs3.1
 * cluster size
 * number of clusters
 * total number of mft records
 * number of used mft records ~= number of files + folders
 * real state of ntfs "dirty"/"clean"
 * current state of ntfs "dirty"/"clean"
*/
static int ntfs3_volinfo(struct seq_file *m, void *o)
{
        struct super_block *sb = m->private;
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        seq_printf(m, "ntfs%d.%d\n%u\n%zu\n%zu\n%zu\n%s\n%s\n",
                   sbi->volume.major_ver, sbi->volume.minor_ver,
                   sbi->cluster_size, sbi->used.bitmap.nbits,
                   sbi->mft.bitmap.nbits,
                   sbi->mft.bitmap.nbits - wnd_zeroes(&sbi->mft.bitmap),
                   sbi->volume.real_dirty ? "dirty" : "clean",
                   (sbi->volume.flags & VOLUME_FLAG_DIRTY) ? "dirty" : "clean");

        return 0;
}

static int ntfs3_volinfo_open(struct inode *inode, struct file *file)
{
        return single_open(file, ntfs3_volinfo, pde_data(inode));
}

/* read /proc/fs/ntfs3/<dev>/label */
static int ntfs3_label_show(struct seq_file *m, void *o)
{
        struct super_block *sb = m->private;
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        seq_printf(m, "%s\n", sbi->volume.label);

        return 0;
}

/* write /proc/fs/ntfs3/<dev>/label */
static ssize_t ntfs3_label_write(struct file *file, const char __user *buffer,
                                 size_t count, loff_t *ppos)
{
        int err;
        struct super_block *sb = pde_data(file_inode(file));
        ssize_t ret = count;
        u8 *label;

        if (sb_rdonly(sb))
                return -EROFS;

        label = kmalloc(count, GFP_NOFS);

        if (!label)
                return -ENOMEM;

        if (copy_from_user(label, buffer, ret)) {
                ret = -EFAULT;
                goto out;
        }
        while (ret > 0 && label[ret - 1] == '\n')
                ret -= 1;

        err = ntfs_set_label(sb->s_fs_info, label, ret);

        if (err < 0) {
                ntfs_err(sb, "failed (%d) to write label", err);
                ret = err;
                goto out;
        }

        *ppos += count;
        ret = count;
out:
        kfree(label);
        return ret;
}

static int ntfs3_label_open(struct inode *inode, struct file *file)
{
        return single_open(file, ntfs3_label_show, pde_data(inode));
}

static const struct proc_ops ntfs3_volinfo_fops = {
        .proc_read = seq_read,
        .proc_lseek = seq_lseek,
        .proc_release = single_release,
        .proc_open = ntfs3_volinfo_open,
};

static const struct proc_ops ntfs3_label_fops = {
        .proc_read = seq_read,
        .proc_lseek = seq_lseek,
        .proc_release = single_release,
        .proc_open = ntfs3_label_open,
        .proc_write = ntfs3_label_write,
};

static void ntfs_create_procdir(struct super_block *sb)
{
        struct proc_dir_entry *e;

        if (!proc_info_root)
                return;

        e = proc_mkdir(sb->s_id, proc_info_root);
        if (e) {
                struct ntfs_sb_info *sbi = sb->s_fs_info;

                proc_create_data("volinfo", 0444, e, &ntfs3_volinfo_fops, sb);
                proc_create_data("label", 0644, e, &ntfs3_label_fops, sb);
                sbi->procdir = e;
        }
}

static void ntfs_remove_procdir(struct super_block *sb)
{
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        if (!sbi->procdir)
                return;

        remove_proc_entry("label", sbi->procdir);
        remove_proc_entry("volinfo", sbi->procdir);
        remove_proc_entry(sb->s_id, proc_info_root);
        sbi->procdir = NULL;
}

static void ntfs_create_proc_root(void)
{
        proc_info_root = proc_mkdir("fs/ntfs3", NULL);
}

static void ntfs_remove_proc_root(void)
{
        if (proc_info_root) {
                remove_proc_entry("fs/ntfs3", NULL);
                proc_info_root = NULL;
        }
}
#else
// clang-format off
static void ntfs_create_procdir(struct super_block *sb){}
static void ntfs_remove_procdir(struct super_block *sb){}
static void ntfs_create_proc_root(void){}
static void ntfs_remove_proc_root(void){}
// clang-format on
#endif

static struct kmem_cache *ntfs_inode_cachep;

static struct inode *ntfs_alloc_inode(struct super_block *sb)
{
        struct ntfs_inode *ni = alloc_inode_sb(sb, ntfs_inode_cachep, GFP_NOFS);

        if (!ni)
                return NULL;

        memset(ni, 0, offsetof(struct ntfs_inode, vfs_inode));
        mutex_init(&ni->ni_lock);
        return &ni->vfs_inode;
}

static void ntfs_free_inode(struct inode *inode)
{
        struct ntfs_inode *ni = ntfs_i(inode);

        mutex_destroy(&ni->ni_lock);
        kmem_cache_free(ntfs_inode_cachep, ni);
}

static void init_once(void *foo)
{
        struct ntfs_inode *ni = foo;

        inode_init_once(&ni->vfs_inode);
}

/*
 * Noinline to reduce binary size.
 */
static noinline void ntfs3_put_sbi(struct ntfs_sb_info *sbi)
{
        wnd_close(&sbi->mft.bitmap);
        wnd_close(&sbi->used.bitmap);

        if (sbi->mft.ni) {
                iput(&sbi->mft.ni->vfs_inode);
                sbi->mft.ni = NULL;
        }

        if (sbi->security.ni) {
                iput(&sbi->security.ni->vfs_inode);
                sbi->security.ni = NULL;
        }

        if (sbi->reparse.ni) {
                iput(&sbi->reparse.ni->vfs_inode);
                sbi->reparse.ni = NULL;
        }

        if (sbi->objid.ni) {
                iput(&sbi->objid.ni->vfs_inode);
                sbi->objid.ni = NULL;
        }

        if (sbi->volume.ni) {
                iput(&sbi->volume.ni->vfs_inode);
                sbi->volume.ni = NULL;
        }

        ntfs_update_mftmirr(sbi);

        indx_clear(&sbi->security.index_sii);
        indx_clear(&sbi->security.index_sdh);
        indx_clear(&sbi->reparse.index_r);
        indx_clear(&sbi->objid.index_o);
}

static void ntfs3_free_sbi(struct ntfs_sb_info *sbi)
{
        kfree(sbi->new_rec);
        kvfree(ntfs_put_shared(sbi->upcase));
        kvfree(sbi->def_table);
        kfree(sbi->compress.lznt);
#ifdef CONFIG_NTFS3_LZX_XPRESS
        xpress_free_decompressor(sbi->compress.xpress);
        lzx_free_decompressor(sbi->compress.lzx);
#endif
        kfree(sbi);
}

static void ntfs_put_super(struct super_block *sb)
{
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        ntfs_remove_procdir(sb);

        /* Mark rw ntfs as clear, if possible. */
        ntfs_set_state(sbi, NTFS_DIRTY_CLEAR);

        if (sbi->options) {
                put_mount_options(sbi->options);
                sbi->options = NULL;
        }

        ntfs3_put_sbi(sbi);
}

static int ntfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct wnd_bitmap *wnd = &sbi->used.bitmap;
        CLST da_clusters = ntfs_get_da(sbi);

        buf->f_type = sb->s_magic;
        buf->f_bsize = buf->f_frsize = sbi->cluster_size;
        buf->f_blocks = wnd->nbits;

        buf->f_bfree = wnd_zeroes(wnd);
        if (buf->f_bfree > da_clusters) {
                buf->f_bfree -= da_clusters;
        } else {
                buf->f_bfree = 0;
        }
        buf->f_bavail = buf->f_bfree;

        buf->f_fsid.val[0] = sbi->volume.ser_num;
        buf->f_fsid.val[1] = sbi->volume.ser_num >> 32;
        buf->f_namelen = NTFS_NAME_LEN;

        return 0;
}

static int ntfs_show_options(struct seq_file *m, struct dentry *root)
{
        struct super_block *sb = root->d_sb;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct ntfs_mount_options *opts = sbi->options;
        struct user_namespace *user_ns = seq_user_ns(m);

        seq_printf(m, ",uid=%u", from_kuid_munged(user_ns, opts->fs_uid));
        seq_printf(m, ",gid=%u", from_kgid_munged(user_ns, opts->fs_gid));
        if (opts->dmask)
                seq_printf(m, ",dmask=%04o", opts->fs_dmask_inv ^ 0xffff);
        if (opts->fmask)
                seq_printf(m, ",fmask=%04o", opts->fs_fmask_inv ^ 0xffff);
        if (opts->sys_immutable)
                seq_puts(m, ",sys_immutable");
        if (opts->discard)
                seq_puts(m, ",discard");
        if (opts->force)
                seq_puts(m, ",force");
        if (opts->sparse)
                seq_puts(m, ",sparse");
        if (opts->nohidden)
                seq_puts(m, ",nohidden");
        if (opts->hide_dot_files)
                seq_puts(m, ",hide_dot_files");
        if (opts->windows_names)
                seq_puts(m, ",windows_names");
        if (opts->showmeta)
                seq_puts(m, ",showmeta");
        if (sb->s_flags & SB_POSIXACL)
                seq_puts(m, ",acl");
        if (opts->nls)
                seq_printf(m, ",iocharset=%s", opts->nls->charset);
        else
                seq_puts(m, ",iocharset=utf8");
        if (opts->prealloc)
                seq_puts(m, ",prealloc");
        if (opts->nocase)
                seq_puts(m, ",nocase");
        if (opts->delalloc)
                seq_puts(m, ",delalloc");

        return 0;
}

/*
 * ntfs_shutdown - super_operations::shutdown
 */
static void ntfs_shutdown(struct super_block *sb)
{
        set_bit(NTFS_FLAGS_SHUTDOWN_BIT, &ntfs_sb(sb)->flags);
}

/*
 * ntfs_sync_fs - super_operations::sync_fs
 */
static int ntfs_sync_fs(struct super_block *sb, int wait)
{
        int err = 0, err2;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct ntfs_inode *ni;
        struct inode *inode;

        if (unlikely(ntfs3_forced_shutdown(sb)))
                return -EIO;

        ni = sbi->security.ni;
        if (ni) {
                inode = &ni->vfs_inode;
                err2 = _ni_write_inode(inode, wait);
                if (err2 && !err)
                        err = err2;
        }

        ni = sbi->objid.ni;
        if (ni) {
                inode = &ni->vfs_inode;
                err2 = _ni_write_inode(inode, wait);
                if (err2 && !err)
                        err = err2;
        }

        ni = sbi->reparse.ni;
        if (ni) {
                inode = &ni->vfs_inode;
                err2 = _ni_write_inode(inode, wait);
                if (err2 && !err)
                        err = err2;
        }

        if (!err)
                ntfs_set_state(sbi, NTFS_DIRTY_CLEAR);

        ntfs_update_mftmirr(sbi);

        if (wait) {
                sync_blockdev(sb->s_bdev);
                blkdev_issue_flush(sb->s_bdev);
        }

        return err;
}

static const struct super_operations ntfs_sops = {
        .alloc_inode = ntfs_alloc_inode,
        .free_inode = ntfs_free_inode,
        .evict_inode = ntfs_evict_inode,
        .put_super = ntfs_put_super,
        .statfs = ntfs_statfs,
        .show_options = ntfs_show_options,
        .shutdown = ntfs_shutdown,
        .sync_fs = ntfs_sync_fs,
        .write_inode = ntfs3_write_inode,
};

static struct inode *ntfs_export_get_inode(struct super_block *sb, u64 ino,
                                           u32 generation)
{
        struct MFT_REF ref;
        struct inode *inode;

        ref.low = cpu_to_le32(ino);
#ifdef CONFIG_NTFS3_64BIT_CLUSTER
        ref.high = cpu_to_le16(ino >> 32);
#else
        ref.high = 0;
#endif
        ref.seq = cpu_to_le16(generation);

        inode = ntfs_iget5(sb, &ref, NULL);
        if (!IS_ERR(inode) && is_bad_inode(inode)) {
                iput(inode);
                inode = ERR_PTR(-ESTALE);
        }

        return inode;
}

static struct dentry *ntfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
                                        int fh_len, int fh_type)
{
        return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
                                    ntfs_export_get_inode);
}

static struct dentry *ntfs_fh_to_parent(struct super_block *sb, struct fid *fid,
                                        int fh_len, int fh_type)
{
        return generic_fh_to_parent(sb, fid, fh_len, fh_type,
                                    ntfs_export_get_inode);
}

/* TODO: == ntfs_sync_inode */
static int ntfs_nfs_commit_metadata(struct inode *inode)
{
        return _ni_write_inode(inode, 1);
}

static const struct export_operations ntfs_export_ops = {
        .encode_fh = generic_encode_ino32_fh,
        .fh_to_dentry = ntfs_fh_to_dentry,
        .fh_to_parent = ntfs_fh_to_parent,
        .get_parent = ntfs3_get_parent,
        .commit_metadata = ntfs_nfs_commit_metadata,
};

/*
 * format_size_gb - Return Gb,Mb to print with "%u.%02u Gb".
 */
static u32 format_size_gb(const u64 bytes, u32 *mb)
{
        /* Do simple right 30 bit shift of 64 bit value. */
        u64 kbytes = bytes >> 10;
        u32 kbytes32 = kbytes;

        *mb = (100 * (kbytes32 & 0xfffff) + 0x7ffff) >> 20;
        if (*mb >= 100)
                *mb = 99;

        return (kbytes32 >> 20) | (((u32)(kbytes >> 32)) << 12);
}

static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot)
{
        if (boot->sectors_per_clusters <= 0x80)
                return boot->sectors_per_clusters;
        if (boot->sectors_per_clusters >= 0xf4) /* limit shift to 2MB max */
                return 1U << (-(s8)boot->sectors_per_clusters);
        return -EINVAL;
}

/*
 * ntfs_init_from_boot - Init internal info from on-disk boot sector.
 *
 * NTFS mount begins from boot - special formatted 512 bytes.
 * There are two boots: the first and the last 512 bytes of volume.
 * The content of boot is not changed during ntfs life.
 *
 * NOTE: ntfs.sys checks only first (primary) boot.
 * chkdsk checks both boots.
 */
static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
                               u64 dev_size, struct NTFS_BOOT **boot2)
{
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        int err;
        u32 mb, gb, boot_sector_size, sct_per_clst, record_size;
        u64 sectors, clusters, mlcn, mlcn2, dev_size0;
        struct NTFS_BOOT *boot;
        struct buffer_head *bh;
        struct MFT_REC *rec;
        u16 fn, ao;
        u8 cluster_bits;
        u32 boot_off = 0;
        sector_t boot_block = 0;
        const char *hint = "Primary boot";

        /* Save original dev_size. Used with alternative boot. */
        dev_size0 = dev_size;

        sbi->volume.blocks = dev_size >> PAGE_SHIFT;

        /* Set dummy blocksize to read boot_block. */
        if (!sb_min_blocksize(sb, PAGE_SIZE)) {
                return -EINVAL;
        }

read_boot:
        bh = ntfs_bread(sb, boot_block);
        if (!bh)
                return boot_block ? -EINVAL : -EIO;

        err = -EINVAL;

        /* Corrupted image; do not read OOB */
        if (bh->b_size - sizeof(*boot) < boot_off)
                goto out;

        boot = (struct NTFS_BOOT *)Add2Ptr(bh->b_data, boot_off);

        if (memcmp(boot->system_id, "NTFS    ", sizeof("NTFS    ") - 1)) {
                ntfs_err(sb, "%s signature is not NTFS.", hint);
                goto out;
        }

        /* 0x55AA is not mandaroty. Thanks Maxim Suhanov*/
        /*if (0x55 != boot->boot_magic[0] || 0xAA != boot->boot_magic[1])
         *      goto out;
         */

        boot_sector_size = ((u32)boot->bytes_per_sector[1] << 8) |
                           boot->bytes_per_sector[0];
        if (boot_sector_size < SECTOR_SIZE ||
            !is_power_of_2(boot_sector_size)) {
                ntfs_err(sb, "%s: invalid bytes per sector %u.", hint,
                         boot_sector_size);
                goto out;
        }

        /* cluster size: 512, 1K, 2K, 4K, ... 2M */
        sct_per_clst = true_sectors_per_clst(boot);
        if ((int)sct_per_clst < 0 || !is_power_of_2(sct_per_clst)) {
                ntfs_err(sb, "%s: invalid sectors per cluster %u.", hint,
                         sct_per_clst);
                goto out;
        }

        sbi->cluster_size = boot_sector_size * sct_per_clst;
        sbi->cluster_bits = cluster_bits = blksize_bits(sbi->cluster_size);
        sbi->cluster_mask = sbi->cluster_size - 1;
        sbi->cluster_mask_inv = ~(u64)sbi->cluster_mask;

        mlcn = le64_to_cpu(boot->mft_clst);
        mlcn2 = le64_to_cpu(boot->mft2_clst);
        sectors = le64_to_cpu(boot->sectors_per_volume);

        if (mlcn * sct_per_clst >= sectors || mlcn2 * sct_per_clst >= sectors) {
                ntfs_err(
                        sb,
                        "%s: start of MFT 0x%llx (0x%llx) is out of volume 0x%llx.",
                        hint, mlcn, mlcn2, sectors);
                goto out;
        }

        if (boot->record_size >= 0) {
                record_size = (u32)boot->record_size << cluster_bits;
        } else if (-boot->record_size <= MAXIMUM_SHIFT_BYTES_PER_MFT) {
                record_size = 1u << (-boot->record_size);
        } else {
                ntfs_err(sb, "%s: invalid record size %d.", hint,
                         boot->record_size);
                goto out;
        }

        sbi->record_size = record_size;
        sbi->record_bits = blksize_bits(record_size);
        sbi->attr_size_tr = (5 * record_size >> 4); // ~320 bytes

        /* Check MFT record size. */
        if (record_size < SECTOR_SIZE || !is_power_of_2(record_size)) {
                ntfs_err(sb, "%s: invalid bytes per MFT record %u (%d).", hint,
                         record_size, boot->record_size);
                goto out;
        }

        if (record_size > MAXIMUM_BYTES_PER_MFT) {
                ntfs_err(sb, "Unsupported bytes per MFT record %u.",
                         record_size);
                goto out;
        }

        if (boot->index_size >= 0) {
                sbi->index_size = (u32)boot->index_size << cluster_bits;
        } else if (-boot->index_size <= MAXIMUM_SHIFT_BYTES_PER_INDEX) {
                sbi->index_size = 1u << (-boot->index_size);
        } else {
                ntfs_err(sb, "%s: invalid index size %d.", hint,
                         boot->index_size);
                goto out;
        }

        /* Check index record size. */
        if (sbi->index_size < SECTOR_SIZE || !is_power_of_2(sbi->index_size)) {
                ntfs_err(sb, "%s: invalid bytes per index %u(%d).", hint,
                         sbi->index_size, boot->index_size);
                goto out;
        }

        if (sbi->index_size > MAXIMUM_BYTES_PER_INDEX) {
                ntfs_err(sb, "%s: unsupported bytes per index %u.", hint,
                         sbi->index_size);
                goto out;
        }

        sbi->volume.size = sectors * boot_sector_size;

        gb = format_size_gb(sbi->volume.size + boot_sector_size, &mb);

        /*
         * - Volume formatted and mounted with the same sector size.
         * - Volume formatted 4K and mounted as 512.
         * - Volume formatted 512 and mounted as 4K.
         */
        if (boot_sector_size != sector_size) {
                ntfs_warn(
                        sb,
                        "Different NTFS sector size (%u) and media sector size (%u).",
                        boot_sector_size, sector_size);
                dev_size += sector_size - 1;
        }

        sbi->bdev_blocksize = max(boot_sector_size, sector_size);
        sbi->mft.lbo = mlcn << cluster_bits;
        sbi->mft.lbo2 = mlcn2 << cluster_bits;

        /* Compare boot's cluster and sector. */
        if (sbi->cluster_size < boot_sector_size) {
                ntfs_err(sb, "%s: invalid bytes per cluster (%u).", hint,
                         sbi->cluster_size);
                goto out;
        }

        /* Compare boot's cluster and media sector. */
        if (sbi->cluster_size < sector_size) {
                /* No way to use ntfs_get_block in this case. */
                ntfs_err(
                        sb,
                        "Failed to mount 'cause NTFS's cluster size (%u) is less than media sector size (%u).",
                        sbi->cluster_size, sector_size);
                goto out;
        }

        sbi->max_bytes_per_attr =
                record_size - ALIGN(MFTRECORD_FIXUP_OFFSET, 8) -
                ALIGN(((record_size >> SECTOR_SHIFT) * sizeof(short)), 8) -
                ALIGN(sizeof(enum ATTR_TYPE), 8);

        sbi->volume.ser_num = le64_to_cpu(boot->serial_num);

        /* Warning if RAW volume. */
        if (dev_size < sbi->volume.size + boot_sector_size) {
                u32 mb0, gb0;

                gb0 = format_size_gb(dev_size, &mb0);
                ntfs_warn(
                        sb,
                        "RAW NTFS volume: Filesystem size %u.%02u Gb > volume size %u.%02u Gb. Mount in read-only.",
                        gb, mb, gb0, mb0);
                sb->s_flags |= SB_RDONLY;
        }

        clusters = sbi->volume.size >> cluster_bits;
#ifndef CONFIG_NTFS3_64BIT_CLUSTER
        /* 32 bits per cluster. */
        if (clusters >> 32) {
                ntfs_notice(
                        sb,
                        "NTFS %u.%02u Gb is too big to use 32 bits per cluster.",
                        gb, mb);
                goto out;
        }
#elif BITS_PER_LONG < 64
#error "CONFIG_NTFS3_64BIT_CLUSTER incompatible in 32 bit OS"
#endif

        sbi->used.bitmap.nbits = clusters;

        rec = kzalloc(record_size, GFP_NOFS);
        if (!rec) {
                err = -ENOMEM;
                goto out;
        }

        sbi->new_rec = rec;
        rec->rhdr.sign = NTFS_FILE_SIGNATURE;
        rec->rhdr.fix_off = cpu_to_le16(MFTRECORD_FIXUP_OFFSET);
        fn = (sbi->record_size >> SECTOR_SHIFT) + 1;
        rec->rhdr.fix_num = cpu_to_le16(fn);
        ao = ALIGN(MFTRECORD_FIXUP_OFFSET + sizeof(short) * fn, 8);
        rec->attr_off = cpu_to_le16(ao);
        rec->used = cpu_to_le32(ao + ALIGN(sizeof(enum ATTR_TYPE), 8));
        rec->total = cpu_to_le32(sbi->record_size);
        ((struct ATTRIB *)Add2Ptr(rec, ao))->type = ATTR_END;

        sb_set_blocksize(sb, min_t(u32, sbi->cluster_size, PAGE_SIZE));

        sbi->block_mask = sb->s_blocksize - 1;
        sbi->blocks_per_cluster = sbi->cluster_size >> sb->s_blocksize_bits;
        sbi->volume.blocks = sbi->volume.size >> sb->s_blocksize_bits;

        /* Maximum size for normal files. */
        sbi->maxbytes = (clusters << cluster_bits) - 1;

#ifdef CONFIG_NTFS3_64BIT_CLUSTER
        if (clusters >= (1ull << (64 - cluster_bits)))
                sbi->maxbytes = -1;
        sbi->maxbytes_sparse = -1;
        sb->s_maxbytes = MAX_LFS_FILESIZE;
#else
        /* Maximum size for sparse file. */
        sbi->maxbytes_sparse = (1ull << (cluster_bits + 32)) - 1;
        sb->s_maxbytes = 0xFFFFFFFFull << cluster_bits;
#endif

        /*
         * Compute the MFT zone at two steps.
         * It would be nice if we are able to allocate 1/8 of
         * total clusters for MFT but not more then 512 MB.
         */
        sbi->zone_max = min_t(CLST, 0x20000000 >> cluster_bits, clusters >> 3);

        err = 0;

        if (bh->b_blocknr && !sb_rdonly(sb)) {
                /*
                 * Alternative boot is ok but primary is not ok.
                 * Do not update primary boot here 'cause it may be faked boot.
                 * Let ntfs to be mounted and update boot later.
                 */
                *boot2 = kmemdup(boot, sizeof(*boot), GFP_NOFS | __GFP_NOWARN);
        }

out:
        brelse(bh);

        if (err == -EINVAL && !boot_block && dev_size0 > PAGE_SHIFT) {
                u32 block_size = min_t(u32, sector_size, PAGE_SIZE);
                u64 lbo = dev_size0 - sizeof(*boot);

                boot_block = lbo >> blksize_bits(block_size);
                boot_off = lbo & (block_size - 1);
                if (boot_block && block_size >= boot_off + sizeof(*boot)) {
                        /*
                         * Try alternative boot (last sector)
                         */
                        sb_set_blocksize(sb, block_size);
                        hint = "Alternative boot";
                        dev_size = dev_size0; /* restore original size. */
                        goto read_boot;
                }
        }

        return err;
}

/*
 * ntfs_fill_super - Try to mount.
 */
static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
        int err;
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct block_device *bdev = sb->s_bdev;
        struct ntfs_mount_options *fc_opts;
        struct ntfs_mount_options *options = NULL;
        struct inode *inode;
        struct ntfs_inode *ni;
        size_t i, tt, bad_len, bad_frags;
        CLST vcn, lcn, len;
        struct ATTRIB *attr;
        const struct VOLUME_INFO *info;
        u32 done, bytes;
        struct ATTR_DEF_ENTRY *t;
        u16 *shared;
        struct MFT_REF ref;
        bool ro = sb_rdonly(sb);
        struct NTFS_BOOT *boot2 = NULL;

        ref.high = 0;

        sbi->sb = sb;
        fc_opts = fc->fs_private;
        if (!fc_opts) {
                errorf(fc, "missing mount options");
                return -EINVAL;
        }
        options = kmemdup(fc_opts, sizeof(*fc_opts), GFP_KERNEL);
        if (!options)
                return -ENOMEM;

        if (fc_opts->nls_name) {
                options->nls_name = kstrdup(fc_opts->nls_name, GFP_KERNEL);
                if (!options->nls_name) {
                        kfree(options);
                        return -ENOMEM;
                }
        }
        sbi->options = options;
        sb->s_flags |= SB_NODIRATIME;
        sb->s_magic = 0x7366746e; // "ntfs"
        sb->s_op = &ntfs_sops;
        sb->s_export_op = &ntfs_export_ops;
        sb->s_time_gran = NTFS_TIME_GRAN; // 100 nsec
        sb->s_xattr = ntfs_xattr_handlers;
        set_default_d_op(sb, options->nocase ? &ntfs_dentry_ops : NULL);

        options->nls = ntfs_load_nls(options->nls_name);
        if (IS_ERR(options->nls)) {
                options->nls = NULL;
                errorf(fc, "Cannot load nls %s", options->nls_name);
                err = -EINVAL;
                goto out;
        }

        if (bdev_max_discard_sectors(bdev) && bdev_discard_granularity(bdev)) {
                sbi->discard_granularity = bdev_discard_granularity(bdev);
                sbi->discard_granularity_mask_inv =
                        ~(u64)(sbi->discard_granularity - 1);
        }

        /* Parse boot. */
        err = ntfs_init_from_boot(sb, bdev_logical_block_size(bdev),
                                  bdev_nr_bytes(bdev), &boot2);
        if (err)
                goto out;

        /*
         * Load $Volume. This should be done before $LogFile
         * 'cause 'sbi->volume.ni' is used in 'ntfs_set_state'.
         */
        ref.low = cpu_to_le32(MFT_REC_VOL);
        ref.seq = cpu_to_le16(MFT_REC_VOL);
        inode = ntfs_iget5(sb, &ref, &NAME_VOLUME);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $Volume (%d).", err);
                goto out;
        }

        ni = ntfs_i(inode);

        /* Load and save label (not necessary). */
        attr = ni_find_attr(ni, NULL, NULL, ATTR_LABEL, NULL, 0, NULL, NULL);

        if (!attr) {
                /* It is ok if no ATTR_LABEL */
        } else if (!attr->non_res && !is_attr_ext(attr)) {
                /* $AttrDef allows labels to be up to 128 symbols. */
                err = utf16s_to_utf8s(resident_data(attr),
                                      le32_to_cpu(attr->res.data_size) >> 1,
                                      UTF16_LITTLE_ENDIAN, sbi->volume.label,
                                      sizeof(sbi->volume.label));
                if (err < 0)
                        sbi->volume.label[0] = 0;
        } else {
                /* Should we break mounting here? */
                //err = -EINVAL;
                //goto put_inode_out;
        }

        attr = ni_find_attr(ni, attr, NULL, ATTR_VOL_INFO, NULL, 0, NULL, NULL);
        if (!attr || is_attr_ext(attr) ||
            !(info = resident_data_ex(attr, SIZEOF_ATTRIBUTE_VOLUME_INFO))) {
                ntfs_err(sb, "$Volume is corrupted.");
                err = -EINVAL;
                goto put_inode_out;
        }

        sbi->volume.major_ver = info->major_ver;
        sbi->volume.minor_ver = info->minor_ver;
        sbi->volume.flags = info->flags;
        sbi->volume.ni = ni;
        if (info->flags & VOLUME_FLAG_DIRTY) {
                sbi->volume.real_dirty = true;
                ntfs_info(sb, "It is recommended to use chkdsk.");
        }

        /* Load $MFTMirr to estimate recs_mirr. */
        ref.low = cpu_to_le32(MFT_REC_MIRR);
        ref.seq = cpu_to_le16(MFT_REC_MIRR);
        inode = ntfs_iget5(sb, &ref, &NAME_MIRROR);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $MFTMirr (%d).", err);
                goto out;
        }

        sbi->mft.recs_mirr = ntfs_up_cluster(sbi, inode->i_size) >>
                             sbi->record_bits;

        iput(inode);

        /* Load LogFile to replay. */
        ref.low = cpu_to_le32(MFT_REC_LOG);
        ref.seq = cpu_to_le16(MFT_REC_LOG);
        inode = ntfs_iget5(sb, &ref, &NAME_LOGFILE);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load \x24LogFile (%d).", err);
                goto out;
        }

        ni = ntfs_i(inode);

        err = ntfs_loadlog_and_replay(ni, sbi);
        if (err)
                goto put_inode_out;

        iput(inode);

        if ((sbi->flags & NTFS_FLAGS_NEED_REPLAY) && !ro) {
                ntfs_warn(sb, "failed to replay log file. Can't mount rw!");
                err = -EINVAL;
                goto out;
        }

        if ((sbi->volume.flags & VOLUME_FLAG_DIRTY) && !ro && !options->force) {
                ntfs_warn(sb, "volume is dirty and \"force\" flag is not set!");
                err = -EINVAL;
                goto out;
        }

        /* Load $MFT. */
        ref.low = cpu_to_le32(MFT_REC_MFT);
        ref.seq = cpu_to_le16(1);

        inode = ntfs_iget5(sb, &ref, &NAME_MFT);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $MFT (%d).", err);
                goto out;
        }

        ni = ntfs_i(inode);

        sbi->mft.used = ni->i_valid >> sbi->record_bits;
        tt = inode->i_size >> sbi->record_bits;
        sbi->mft.next_free = MFT_REC_USER;

        err = wnd_init(&sbi->mft.bitmap, sb, tt);
        if (err)
                goto put_inode_out;

        err = ni_load_all_mi(ni);
        if (err) {
                ntfs_err(sb, "Failed to load $MFT's subrecords (%d).", err);
                goto put_inode_out;
        }

        sbi->mft.ni = ni;

        /* Load $Bitmap. */
        ref.low = cpu_to_le32(MFT_REC_BITMAP);
        ref.seq = cpu_to_le16(MFT_REC_BITMAP);
        inode = ntfs_iget5(sb, &ref, &NAME_BITMAP);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $Bitmap (%d).", err);
                goto out;
        }

#ifndef CONFIG_NTFS3_64BIT_CLUSTER
        if (inode->i_size >> 32) {
                err = -EINVAL;
                goto put_inode_out;
        }
#endif

        /* Check bitmap boundary. */
        tt = sbi->used.bitmap.nbits;
        if (inode->i_size < ntfs3_bitmap_size(tt)) {
                ntfs_err(sb, "$Bitmap is corrupted.");
                err = -EINVAL;
                goto put_inode_out;
        }

        err = wnd_init(&sbi->used.bitmap, sb, tt);
        if (err) {
                ntfs_err(sb, "Failed to initialize $Bitmap (%d).", err);
                goto put_inode_out;
        }

        iput(inode);

        /* Compute the MFT zone. */
        err = ntfs_refresh_zone(sbi);
        if (err) {
                ntfs_err(sb, "Failed to initialize MFT zone (%d).", err);
                goto out;
        }

        /* Load $BadClus. */
        ref.low = cpu_to_le32(MFT_REC_BADCLUST);
        ref.seq = cpu_to_le16(MFT_REC_BADCLUST);
        inode = ntfs_iget5(sb, &ref, &NAME_BADCLUS);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $BadClus (%d).", err);
                goto out;
        }

        ni = ntfs_i(inode);
        bad_len = bad_frags = 0;
        for (i = 0; run_get_entry(&ni->file.run, i, &vcn, &lcn, &len); i++) {
                if (lcn == SPARSE_LCN)
                        continue;

                bad_len += len;
                bad_frags += 1;
                if (ro)
                        continue;

                if (wnd_set_used_safe(&sbi->used.bitmap, lcn, len, &tt) || tt) {
                        /* Bad blocks marked as free in bitmap. */
                        ntfs_set_state(sbi, NTFS_DIRTY_ERROR);
                }
        }
        if (bad_len) {
                /*
                 * Notice about bad blocks.
                 * In normal cases these blocks are marked as used in bitmap.
                 * And we never allocate space in it.
                 */
                ntfs_notice(sb,
                            "Volume contains %zu bad blocks in %zu fragments.",
                            bad_len, bad_frags);
        }
        iput(inode);

        /* Load $AttrDef. */
        ref.low = cpu_to_le32(MFT_REC_ATTR);
        ref.seq = cpu_to_le16(MFT_REC_ATTR);
        inode = ntfs_iget5(sb, &ref, &NAME_ATTRDEF);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $AttrDef (%d)", err);
                goto out;
        }

        /*
         * Typical $AttrDef contains up to 20 entries.
         * Check for extremely large/small size.
         */
        if (inode->i_size < sizeof(struct ATTR_DEF_ENTRY) ||
            inode->i_size > 100 * sizeof(struct ATTR_DEF_ENTRY)) {
                ntfs_err(sb, "Looks like $AttrDef is corrupted (size=%llu).",
                         inode->i_size);
                err = -EINVAL;
                goto put_inode_out;
        }

        bytes = inode->i_size;
        sbi->def_table = t = kvmalloc(bytes, GFP_KERNEL);
        if (!t) {
                err = -ENOMEM;
                goto put_inode_out;
        }

        /* Read the entire file. */
        err = inode_read_data(inode, sbi->def_table, bytes);
        if (err) {
                ntfs_err(sb, "Failed to read $AttrDef (%d).", err);
                goto put_inode_out;
        }

        if (ATTR_STD != t->type) {
                ntfs_err(sb, "$AttrDef is corrupted.");
                err = -EINVAL;
                goto put_inode_out;
        }

        t += 1;
        sbi->def_entries = 1;
        done = sizeof(struct ATTR_DEF_ENTRY);

        while (done + sizeof(struct ATTR_DEF_ENTRY) <= bytes) {
                u32 t32 = le32_to_cpu(t->type);
                u64 sz = le64_to_cpu(t->max_sz);

                if ((t32 & 0xF) || le32_to_cpu(t[-1].type) >= t32)
                        break;

                if (t->type == ATTR_REPARSE)
                        sbi->reparse.max_size = sz;
                else if (t->type == ATTR_EA)
                        sbi->ea_max_size = sz;

                done += sizeof(struct ATTR_DEF_ENTRY);
                t += 1;
                sbi->def_entries += 1;
        }
        iput(inode);

        /* Load $UpCase. */
        ref.low = cpu_to_le32(MFT_REC_UPCASE);
        ref.seq = cpu_to_le16(MFT_REC_UPCASE);
        inode = ntfs_iget5(sb, &ref, &NAME_UPCASE);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load $UpCase (%d).", err);
                goto out;
        }

        if (inode->i_size != 0x10000 * sizeof(short)) {
                err = -EINVAL;
                ntfs_err(sb, "$UpCase is corrupted.");
                goto put_inode_out;
        }

        /* Read the entire file. */
        err = inode_read_data(inode, sbi->upcase, 0x10000 * sizeof(short));
        if (err) {
                ntfs_err(sb, "Failed to read $UpCase (%d).", err);
                goto put_inode_out;
        }

#ifdef __BIG_ENDIAN
        {
                u16 *dst = sbi->upcase;

                for (i = 0; i < 0x10000; i++)
                        __swab16s(dst++);
        }
#endif

        shared = ntfs_set_shared(sbi->upcase, 0x10000 * sizeof(short));
        if (shared && sbi->upcase != shared) {
                kvfree(sbi->upcase);
                sbi->upcase = shared;
        }

        iput(inode);

        if (is_ntfs3(sbi)) {
                /* Load $Secure. */
                err = ntfs_security_init(sbi);
                if (err) {
                        ntfs_err(sb, "Failed to initialize $Secure (%d).", err);
                        goto out;
                }

                /* Load $Extend. */
                err = ntfs_extend_init(sbi);
                if (err) {
                        ntfs_warn(sb, "Failed to initialize $Extend.");
                        goto load_root;
                }

                /* Load $Extend/$Reparse. */
                err = ntfs_reparse_init(sbi);
                if (err) {
                        ntfs_warn(sb, "Failed to initialize $Extend/$Reparse.");
                        goto load_root;
                }

                /* Load $Extend/$ObjId. */
                err = ntfs_objid_init(sbi);
                if (err) {
                        ntfs_warn(sb, "Failed to initialize $Extend/$ObjId.");
                        goto load_root;
                }
        }

load_root:
        /* Load root. */
        ref.low = cpu_to_le32(MFT_REC_ROOT);
        ref.seq = cpu_to_le16(MFT_REC_ROOT);
        inode = ntfs_iget5(sb, &ref, &NAME_ROOT);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                ntfs_err(sb, "Failed to load root (%d).", err);
                goto out;
        }

        /*
         * Final check. Looks like this case should never occurs.
         */
        if (!inode->i_op) {
                err = -EINVAL;
                ntfs_err(sb, "Failed to load root (%d).", err);
                goto put_inode_out;
        }

        sb->s_root = d_make_root(inode);
        if (!sb->s_root) {
                err = -ENOMEM;
                goto put_inode_out;
        }

        if (boot2) {
                /*
                 * Alternative boot is ok but primary is not ok.
                 * Volume is recognized as NTFS. Update primary boot.
                 */
                struct buffer_head *bh0 = sb_getblk(sb, 0);
                if (bh0) {
                        wait_on_buffer(bh0);
                        lock_buffer(bh0);
                        memcpy(bh0->b_data, boot2, sizeof(*boot2));
                        set_buffer_uptodate(bh0);
                        mark_buffer_dirty(bh0);
                        unlock_buffer(bh0);
                        if (!sync_dirty_buffer(bh0))
                                ntfs_warn(sb, "primary boot is updated");
                        put_bh(bh0);
                }

                kfree(boot2);
        }

        ntfs_create_procdir(sb);

        if (is_legacy_ntfs(sb))
                sb->s_flags |= SB_RDONLY;
        return 0;

put_inode_out:
        iput(inode);
out:
        /* sbi->options == options */
        if (options) {
                put_mount_options(sbi->options);
                sbi->options = NULL;
        }

        ntfs3_put_sbi(sbi);
        kfree(boot2);
        return err;
}

void ntfs_unmap_meta(struct super_block *sb, CLST lcn, CLST len)
{
        struct ntfs_sb_info *sbi = sb->s_fs_info;
        struct block_device *bdev = sb->s_bdev;
        sector_t devblock = (u64)lcn * sbi->blocks_per_cluster;
        unsigned long blocks = (u64)len * sbi->blocks_per_cluster;
        unsigned long cnt = 0;
        unsigned long limit = global_zone_page_state(NR_FREE_PAGES)
                              << (PAGE_SHIFT - sb->s_blocksize_bits);

        if (limit >= 0x2000)
                limit -= 0x1000;
        else if (limit < 32)
                limit = 32;
        else
                limit >>= 1;

        while (blocks--) {
                clean_bdev_aliases(bdev, devblock++, 1);
                if (cnt++ >= limit) {
                        sync_blockdev(bdev);
                        cnt = 0;
                }
        }
}

/*
 * ntfs_discard - Issue a discard request (trim for SSD).
 */
int ntfs_discard(struct ntfs_sb_info *sbi, CLST lcn, CLST len)
{
        int err;
        u64 lbo, bytes, start, end;
        struct super_block *sb;

        if (sbi->used.next_free_lcn == lcn + len)
                sbi->used.next_free_lcn = lcn;

        if (sbi->flags & NTFS_FLAGS_NODISCARD)
                return -EOPNOTSUPP;

        if (!sbi->options->discard)
                return -EOPNOTSUPP;

        lbo = (u64)lcn << sbi->cluster_bits;
        bytes = (u64)len << sbi->cluster_bits;

        /* Align up 'start' on discard_granularity. */
        start = (lbo + sbi->discard_granularity - 1) &
                sbi->discard_granularity_mask_inv;
        /* Align down 'end' on discard_granularity. */
        end = (lbo + bytes) & sbi->discard_granularity_mask_inv;

        sb = sbi->sb;
        if (start >= end)
                return 0;

        err = blkdev_issue_discard(sb->s_bdev, start >> 9, (end - start) >> 9,
                                   GFP_NOFS);

        if (err == -EOPNOTSUPP)
                sbi->flags |= NTFS_FLAGS_NODISCARD;

        return err;
}

static int ntfs_fs_get_tree(struct fs_context *fc)
{
        return get_tree_bdev(fc, ntfs_fill_super);
}

/*
 * ntfs_fs_free - Free fs_context.
 *
 * Note that this will be called after fill_super and reconfigure
 * even when they pass. So they have to take pointers if they pass.
 */
static void ntfs_fs_free(struct fs_context *fc)
{
        struct ntfs_mount_options *opts = fc->fs_private;
        struct ntfs_sb_info *sbi = fc->s_fs_info;

        if (sbi) {
                ntfs3_put_sbi(sbi);
                ntfs3_free_sbi(sbi);
        }

        if (opts)
                put_mount_options(opts);
}

// clang-format off
static const struct fs_context_operations ntfs_context_ops = {
        .parse_param    = ntfs_fs_parse_param,
        .get_tree       = ntfs_fs_get_tree,
        .reconfigure    = ntfs_fs_reconfigure,
        .free           = ntfs_fs_free,
};
// clang-format on

/*
 * ntfs_init_fs_context - Initialize sbi and opts
 *
 * This will called when mount/remount. We will first initialize
 * options so that if remount we can use just that.
 */
static int __ntfs_init_fs_context(struct fs_context *fc)
{
        struct ntfs_mount_options *opts;
        struct ntfs_sb_info *sbi;

        opts = kzalloc_obj(struct ntfs_mount_options, GFP_NOFS);
        if (!opts)
                return -ENOMEM;

        /* Default options. */
        opts->fs_uid = current_uid();
        opts->fs_gid = current_gid();
        opts->fs_fmask_inv = ~current_umask();
        opts->fs_dmask_inv = ~current_umask();
        opts->prealloc = 1;

#ifdef CONFIG_NTFS3_FS_POSIX_ACL
        /* Set the default value 'acl' */
        fc->sb_flags |= SB_POSIXACL;
#endif

        if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
                goto ok;

        sbi = kzalloc_obj(struct ntfs_sb_info, GFP_NOFS);
        if (!sbi)
                goto free_opts;

        sbi->upcase = kvmalloc(0x10000 * sizeof(short), GFP_KERNEL);
        if (!sbi->upcase)
                goto free_sbi;

        ratelimit_state_init(&sbi->msg_ratelimit, DEFAULT_RATELIMIT_INTERVAL,
                             DEFAULT_RATELIMIT_BURST);

        mutex_init(&sbi->compress.mtx_lznt);
#ifdef CONFIG_NTFS3_LZX_XPRESS
        mutex_init(&sbi->compress.mtx_xpress);
        mutex_init(&sbi->compress.mtx_lzx);
#endif

        fc->s_fs_info = sbi;
ok:
        fc->fs_private = opts;
        fc->ops = &ntfs_context_ops;

        return 0;
free_sbi:
        kfree(sbi);
free_opts:
        kfree(opts);
        return -ENOMEM;
}

static int ntfs_init_fs_context(struct fs_context *fc)
{
        return __ntfs_init_fs_context(fc);
}

static void ntfs3_kill_sb(struct super_block *sb)
{
        struct ntfs_sb_info *sbi = sb->s_fs_info;

        kill_block_super(sb);

        if (sbi->options)
                put_mount_options(sbi->options);
        ntfs3_free_sbi(sbi);
}

// clang-format off
static struct file_system_type ntfs_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "ntfs3",
        .init_fs_context        = ntfs_init_fs_context,
        .parameters             = ntfs_fs_parameters,
        .kill_sb                = ntfs3_kill_sb,
        .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};

#if IS_ENABLED(CONFIG_NTFS_FS)
static int ntfs_legacy_init_fs_context(struct fs_context *fc)
{
        int ret;

        ret = __ntfs_init_fs_context(fc);
        /* If ntfs3 is used as legacy ntfs enforce read-only mode. */
        fc->sb_flags |= SB_RDONLY;
        return ret;
}

static struct file_system_type ntfs_legacy_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "ntfs",
        .init_fs_context        = ntfs_legacy_init_fs_context,
        .parameters             = ntfs_fs_parameters,
        .kill_sb                = ntfs3_kill_sb,
        .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("ntfs");

static inline void register_as_ntfs_legacy(void)
{
        int err = register_filesystem(&ntfs_legacy_fs_type);
        if (err)
                pr_warn("ntfs3: Failed to register legacy ntfs filesystem driver: %d\n", err);
}

static inline void unregister_as_ntfs_legacy(void)
{
        unregister_filesystem(&ntfs_legacy_fs_type);
}
bool is_legacy_ntfs(struct super_block *sb)
{
        return sb->s_type == &ntfs_legacy_fs_type;
}
#else
static inline void register_as_ntfs_legacy(void) {}
static inline void unregister_as_ntfs_legacy(void) {}
#endif

// clang-format on

static int __init init_ntfs_fs(void)
{
        int err;

        if (IS_ENABLED(CONFIG_NTFS3_FS_POSIX_ACL))
                pr_info("ntfs3: Enabled Linux POSIX ACLs support\n");
        if (IS_ENABLED(CONFIG_NTFS3_64BIT_CLUSTER))
                pr_notice(
                        "ntfs3: Warning: Activated 64 bits per cluster. Windows does not support this\n");
        if (IS_ENABLED(CONFIG_NTFS3_LZX_XPRESS))
                pr_info("ntfs3: Read-only LZX/Xpress compression included\n");

        ntfs_create_proc_root();

        err = ntfs3_init_bitmap();
        if (err)
                goto out2;

        ntfs_inode_cachep = kmem_cache_create(
                "ntfs_inode_cache", sizeof(struct ntfs_inode), 0,
                (SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT), init_once);
        if (!ntfs_inode_cachep) {
                err = -ENOMEM;
                goto out1;
        }

        register_as_ntfs_legacy();
        err = register_filesystem(&ntfs_fs_type);
        if (err)
                goto out;

        return 0;
out:
        kmem_cache_destroy(ntfs_inode_cachep);
out1:
        ntfs3_exit_bitmap();
out2:
        ntfs_remove_proc_root();
        return err;
}

static void __exit exit_ntfs_fs(void)
{
        rcu_barrier();
        kmem_cache_destroy(ntfs_inode_cachep);
        unregister_filesystem(&ntfs_fs_type);
        unregister_as_ntfs_legacy();
        ntfs3_exit_bitmap();
        ntfs_remove_proc_root();
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ntfs3 read/write filesystem");
#ifdef CONFIG_NTFS3_FS_POSIX_ACL
MODULE_INFO(behaviour, "Enabled Linux POSIX ACLs support");
#endif
#ifdef CONFIG_NTFS3_64BIT_CLUSTER
MODULE_INFO(
        cluster,
        "Warning: Activated 64 bits per cluster. Windows does not support this");
#endif
#ifdef CONFIG_NTFS3_LZX_XPRESS
MODULE_INFO(compression, "Read-only lzx/xpress compression included");
#endif

MODULE_AUTHOR("Konstantin Komarov");
MODULE_ALIAS_FS("ntfs3");

module_init(init_ntfs_fs);
module_exit(exit_ntfs_fs);