// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/fs/isofs/inode.c
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 *      1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
 *      1994  Eberhard Mönkeberg - multi session handling.
 *      1995  Mark Dobie - allow mounting of some weird VideoCDs and PhotoCDs.
 *      1997  Gordon Chaffee - Joliet CDs
 *      1998  Eric Lammerts - ISO 9660 Level 3
 *      2004  Paul Serice - Inode Support pushed out from 4GB to 128GB
 *      2004  Paul Serice - NFS Export Operations
 */

#include <linux/init.h>
#include <linux/module.h>

#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/nls.h>
#include <linux/ctype.h>
#include <linux/statfs.h>
#include <linux/cdrom.h>
#include <linux/parser.h>
#include <linux/mpage.h>
#include <linux/user_namespace.h>
#include <linux/seq_file.h>
#include <linux/blkdev.h>

#include "isofs.h"
#include "zisofs.h"

/* max tz offset is 13 hours */
#define MAX_TZ_OFFSET (52*15*60)

#define BEQUIET

static int isofs_hashi(const struct dentry *parent, struct qstr *qstr);
static int isofs_dentry_cmpi(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name);

#ifdef CONFIG_JOLIET
static int isofs_hashi_ms(const struct dentry *parent, struct qstr *qstr);
static int isofs_hash_ms(const struct dentry *parent, struct qstr *qstr);
static int isofs_dentry_cmpi_ms(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name);
static int isofs_dentry_cmp_ms(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name);
#endif

static void isofs_put_super(struct super_block *sb)
{
        struct isofs_sb_info *sbi = ISOFS_SB(sb);

#ifdef CONFIG_JOLIET
        unload_nls(sbi->s_nls_iocharset);
#endif

        kfree(sbi);
        sb->s_fs_info = NULL;
        return;
}

static int isofs_read_inode(struct inode *, int relocated);
static int isofs_statfs (struct dentry *, struct kstatfs *);
static int isofs_show_options(struct seq_file *, struct dentry *);

static struct kmem_cache *isofs_inode_cachep;

static struct inode *isofs_alloc_inode(struct super_block *sb)
{
        struct iso_inode_info *ei;
        ei = kmem_cache_alloc(isofs_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;
        return &ei->vfs_inode;
}

static void isofs_free_inode(struct inode *inode)
{
        kmem_cache_free(isofs_inode_cachep, ISOFS_I(inode));
}

static void init_once(void *foo)
{
        struct iso_inode_info *ei = foo;

        inode_init_once(&ei->vfs_inode);
}

static int __init init_inodecache(void)
{
        isofs_inode_cachep = kmem_cache_create("isofs_inode_cache",
                                        sizeof(struct iso_inode_info),
                                        0, (SLAB_RECLAIM_ACCOUNT|
                                        SLAB_MEM_SPREAD|SLAB_ACCOUNT),
                                        init_once);
        if (!isofs_inode_cachep)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        /*
         * Make sure all delayed rcu free inodes are flushed before we
         * destroy cache.
         */
        rcu_barrier();
        kmem_cache_destroy(isofs_inode_cachep);
}

static int isofs_remount(struct super_block *sb, int *flags, char *data)
{
        sync_filesystem(sb);
        if (!(*flags & SB_RDONLY))
                return -EROFS;
        return 0;
}

static const struct super_operations isofs_sops = {
        .alloc_inode    = isofs_alloc_inode,
        .free_inode     = isofs_free_inode,
        .put_super      = isofs_put_super,
        .statfs         = isofs_statfs,
        .remount_fs     = isofs_remount,
        .show_options   = isofs_show_options,
};


static const struct dentry_operations isofs_dentry_ops[] = {
        {
                .d_hash         = isofs_hashi,
                .d_compare      = isofs_dentry_cmpi,
        },
#ifdef CONFIG_JOLIET
        {
                .d_hash         = isofs_hash_ms,
                .d_compare      = isofs_dentry_cmp_ms,
        },
        {
                .d_hash         = isofs_hashi_ms,
                .d_compare      = isofs_dentry_cmpi_ms,
        },
#endif
};

struct iso9660_options{
        unsigned int rock:1;
        unsigned int joliet:1;
        unsigned int cruft:1;
        unsigned int hide:1;
        unsigned int showassoc:1;
        unsigned int nocompress:1;
        unsigned int overriderockperm:1;
        unsigned int uid_set:1;
        unsigned int gid_set:1;
        unsigned int utf8:1;
        unsigned char map;
        unsigned char check;
        unsigned int blocksize;
        umode_t fmode;
        umode_t dmode;
        kgid_t gid;
        kuid_t uid;
        char *iocharset;
        /* LVE */
        s32 session;
        s32 sbsector;
};

/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hashi_common(const struct dentry *dentry, struct qstr *qstr, int ms)
{
        const char *name;
        int len;
        char c;
        unsigned long hash;

        len = qstr->len;
        name = qstr->name;
        if (ms) {
                while (len && name[len-1] == '.')
                        len--;
        }

        hash = init_name_hash(dentry);
        while (len--) {
                c = tolower(*name++);
                hash = partial_name_hash(c, hash);
        }
        qstr->hash = end_name_hash(hash);

        return 0;
}

/*
 * Compare of two isofs names.
 */
static int isofs_dentry_cmp_common(
                unsigned int len, const char *str,
                const struct qstr *name, int ms, int ci)
{
        int alen, blen;

        /* A filename cannot end in '.' or we treat it like it has none */
        alen = name->len;
        blen = len;
        if (ms) {
                while (alen && name->name[alen-1] == '.')
                        alen--;
                while (blen && str[blen-1] == '.')
                        blen--;
        }
        if (alen == blen) {
                if (ci) {
                        if (strncasecmp(name->name, str, alen) == 0)
                                return 0;
                } else {
                        if (strncmp(name->name, str, alen) == 0)
                                return 0;
                }
        }
        return 1;
}

static int
isofs_hashi(const struct dentry *dentry, struct qstr *qstr)
{
        return isofs_hashi_common(dentry, qstr, 0);
}

static int
isofs_dentry_cmpi(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name)
{
        return isofs_dentry_cmp_common(len, str, name, 0, 1);
}

#ifdef CONFIG_JOLIET
/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hash_common(const struct dentry *dentry, struct qstr *qstr, int ms)
{
        const char *name;
        int len;

        len = qstr->len;
        name = qstr->name;
        if (ms) {
                while (len && name[len-1] == '.')
                        len--;
        }

        qstr->hash = full_name_hash(dentry, name, len);

        return 0;
}

static int
isofs_hash_ms(const struct dentry *dentry, struct qstr *qstr)
{
        return isofs_hash_common(dentry, qstr, 1);
}

static int
isofs_hashi_ms(const struct dentry *dentry, struct qstr *qstr)
{
        return isofs_hashi_common(dentry, qstr, 1);
}

static int
isofs_dentry_cmp_ms(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name)
{
        return isofs_dentry_cmp_common(len, str, name, 1, 0);
}

static int
isofs_dentry_cmpi_ms(const struct dentry *dentry,
                unsigned int len, const char *str, const struct qstr *name)
{
        return isofs_dentry_cmp_common(len, str, name, 1, 1);
}
#endif

enum {
        Opt_block, Opt_check_r, Opt_check_s, Opt_cruft, Opt_gid, Opt_ignore,
        Opt_iocharset, Opt_map_a, Opt_map_n, Opt_map_o, Opt_mode, Opt_nojoliet,
        Opt_norock, Opt_sb, Opt_session, Opt_uid, Opt_unhide, Opt_utf8, Opt_err,
        Opt_nocompress, Opt_hide, Opt_showassoc, Opt_dmode, Opt_overriderockperm,
};

static const match_table_t tokens = {
        {Opt_norock, "norock"},
        {Opt_nojoliet, "nojoliet"},
        {Opt_unhide, "unhide"},
        {Opt_hide, "hide"},
        {Opt_showassoc, "showassoc"},
        {Opt_cruft, "cruft"},
        {Opt_utf8, "utf8"},
        {Opt_iocharset, "iocharset=%s"},
        {Opt_map_a, "map=acorn"},
        {Opt_map_a, "map=a"},
        {Opt_map_n, "map=normal"},
        {Opt_map_n, "map=n"},
        {Opt_map_o, "map=off"},
        {Opt_map_o, "map=o"},
        {Opt_session, "session=%u"},
        {Opt_sb, "sbsector=%u"},
        {Opt_check_r, "check=relaxed"},
        {Opt_check_r, "check=r"},
        {Opt_check_s, "check=strict"},
        {Opt_check_s, "check=s"},
        {Opt_uid, "uid=%u"},
        {Opt_gid, "gid=%u"},
        {Opt_mode, "mode=%u"},
        {Opt_dmode, "dmode=%u"},
        {Opt_overriderockperm, "overriderockperm"},
        {Opt_block, "block=%u"},
        {Opt_ignore, "conv=binary"},
        {Opt_ignore, "conv=b"},
        {Opt_ignore, "conv=text"},
        {Opt_ignore, "conv=t"},
        {Opt_ignore, "conv=mtext"},
        {Opt_ignore, "conv=m"},
        {Opt_ignore, "conv=auto"},
        {Opt_ignore, "conv=a"},
        {Opt_nocompress, "nocompress"},
        {Opt_err, NULL}
};

static int parse_options(char *options, struct iso9660_options *popt)
{
        char *p;
        int option;
        unsigned int uv;

        popt->map = 'n';
        popt->rock = 1;
        popt->joliet = 1;
        popt->cruft = 0;
        popt->hide = 0;
        popt->showassoc = 0;
        popt->check = 'u';              /* unset */
        popt->nocompress = 0;
        popt->blocksize = 1024;
        popt->fmode = popt->dmode = ISOFS_INVALID_MODE;
        popt->uid_set = 0;
        popt->gid_set = 0;
        popt->gid = GLOBAL_ROOT_GID;
        popt->uid = GLOBAL_ROOT_UID;
        popt->iocharset = NULL;
        popt->utf8 = 0;
        popt->overriderockperm = 0;
        popt->session=-1;
        popt->sbsector=-1;
        if (!options)
                return 1;

        while ((p = strsep(&options, ",")) != NULL) {
                int token;
                substring_t args[MAX_OPT_ARGS];
                unsigned n;

                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_norock:
                        popt->rock = 0;
                        break;
                case Opt_nojoliet:
                        popt->joliet = 0;
                        break;
                case Opt_hide:
                        popt->hide = 1;
                        break;
                case Opt_unhide:
                case Opt_showassoc:
                        popt->showassoc = 1;
                        break;
                case Opt_cruft:
                        popt->cruft = 1;
                        break;
                case Opt_utf8:
                        popt->utf8 = 1;
                        break;
#ifdef CONFIG_JOLIET
                case Opt_iocharset:
                        kfree(popt->iocharset);
                        popt->iocharset = match_strdup(&args[0]);
                        if (!popt->iocharset)
                                return 0;
                        break;
#endif
                case Opt_map_a:
                        popt->map = 'a';
                        break;
                case Opt_map_o:
                        popt->map = 'o';
                        break;
                case Opt_map_n:
                        popt->map = 'n';
                        break;
                case Opt_session:
                        if (match_int(&args[0], &option))
                                return 0;
                        n = option;
                        /*
                         * Track numbers are supposed to be in range 1-99, the
                         * mount option starts indexing at 0.
                         */
                        if (n >= 99)
                                return 0;
                        popt->session = n + 1;
                        break;
                case Opt_sb:
                        if (match_int(&args[0], &option))
                                return 0;
                        popt->sbsector = option;
                        break;
                case Opt_check_r:
                        popt->check = 'r';
                        break;
                case Opt_check_s:
                        popt->check = 's';
                        break;
                case Opt_ignore:
                        break;
                case Opt_uid:
                        if (match_uint(&args[0], &uv))
                                return 0;
                        popt->uid = make_kuid(current_user_ns(), uv);
                        if (!uid_valid(popt->uid))
                                return 0;
                        popt->uid_set = 1;
                        break;
                case Opt_gid:
                        if (match_uint(&args[0], &uv))
                                return 0;
                        popt->gid = make_kgid(current_user_ns(), uv);
                        if (!gid_valid(popt->gid))
                                return 0;
                        popt->gid_set = 1;
                        break;
                case Opt_mode:
                        if (match_int(&args[0], &option))
                                return 0;
                        popt->fmode = option;
                        break;
                case Opt_dmode:
                        if (match_int(&args[0], &option))
                                return 0;
                        popt->dmode = option;
                        break;
                case Opt_overriderockperm:
                        popt->overriderockperm = 1;
                        break;
                case Opt_block:
                        if (match_int(&args[0], &option))
                                return 0;
                        n = option;
                        if (n != 512 && n != 1024 && n != 2048)
                                return 0;
                        popt->blocksize = n;
                        break;
                case Opt_nocompress:
                        popt->nocompress = 1;
                        break;
                default:
                        return 0;
                }
        }
        return 1;
}

/*
 * Display the mount options in /proc/mounts.
 */
static int isofs_show_options(struct seq_file *m, struct dentry *root)
{
        struct isofs_sb_info *sbi = ISOFS_SB(root->d_sb);

        if (!sbi->s_rock)               seq_puts(m, ",norock");
        else if (!sbi->s_joliet_level)  seq_puts(m, ",nojoliet");
        if (sbi->s_cruft)               seq_puts(m, ",cruft");
        if (sbi->s_hide)                seq_puts(m, ",hide");
        if (sbi->s_nocompress)          seq_puts(m, ",nocompress");
        if (sbi->s_overriderockperm)    seq_puts(m, ",overriderockperm");
        if (sbi->s_showassoc)           seq_puts(m, ",showassoc");
        if (sbi->s_utf8)                seq_puts(m, ",utf8");

        if (sbi->s_check)               seq_printf(m, ",check=%c", sbi->s_check);
        if (sbi->s_mapping)             seq_printf(m, ",map=%c", sbi->s_mapping);
        if (sbi->s_session != 255)      seq_printf(m, ",session=%u", sbi->s_session - 1);
        if (sbi->s_sbsector != -1)      seq_printf(m, ",sbsector=%u", sbi->s_sbsector);

        if (root->d_sb->s_blocksize != 1024)
                seq_printf(m, ",blocksize=%lu", root->d_sb->s_blocksize);

        if (sbi->s_uid_set)
                seq_printf(m, ",uid=%u",
                           from_kuid_munged(&init_user_ns, sbi->s_uid));
        if (sbi->s_gid_set)
                seq_printf(m, ",gid=%u",
                           from_kgid_munged(&init_user_ns, sbi->s_gid));

        if (sbi->s_dmode != ISOFS_INVALID_MODE)
                seq_printf(m, ",dmode=%o", sbi->s_dmode);
        if (sbi->s_fmode != ISOFS_INVALID_MODE)
                seq_printf(m, ",fmode=%o", sbi->s_fmode);

#ifdef CONFIG_JOLIET
        if (sbi->s_nls_iocharset &&
            strcmp(sbi->s_nls_iocharset->charset, CONFIG_NLS_DEFAULT) != 0)
                seq_printf(m, ",iocharset=%s", sbi->s_nls_iocharset->charset);
#endif
        return 0;
}

/*
 * look if the driver can tell the multi session redirection value
 *
 * don't change this if you don't know what you do, please!
 * Multisession is legal only with XA disks.
 * A non-XA disk with more than one volume descriptor may do it right, but
 * usually is written in a nowhere standardized "multi-partition" manner.
 * Multisession uses absolute addressing (solely the first frame of the whole
 * track is #0), multi-partition uses relative addressing (each first frame of
 * each track is #0), and a track is not a session.
 *
 * A broken CDwriter software or drive firmware does not set new standards,
 * at least not if conflicting with the existing ones.
 *
 * emoenke@gwdg.de
 */
#define WE_OBEY_THE_WRITTEN_STANDARDS 1

static unsigned int isofs_get_last_session(struct super_block *sb, s32 session)
{
        struct cdrom_device_info *cdi = disk_to_cdi(sb->s_bdev->bd_disk);
        unsigned int vol_desc_start = 0;

        if (session > 0) {
                struct cdrom_tocentry te;

                if (!cdi)
                        return 0;

                te.cdte_track = session;
                te.cdte_format = CDROM_LBA;
                if (cdrom_read_tocentry(cdi, &te) == 0) {
                        printk(KERN_DEBUG "ISOFS: Session %d start %d type %d\n",
                                session, te.cdte_addr.lba,
                                te.cdte_ctrl & CDROM_DATA_TRACK);
                        if ((te.cdte_ctrl & CDROM_DATA_TRACK) == 4)
                                return te.cdte_addr.lba;
                }

                printk(KERN_ERR "ISOFS: Invalid session number or type of track\n");
        }

        if (cdi) {
                struct cdrom_multisession ms_info;

                ms_info.addr_format = CDROM_LBA;
                if (cdrom_multisession(cdi, &ms_info) == 0) {
#if WE_OBEY_THE_WRITTEN_STANDARDS
                        /* necessary for a valid ms_info.addr */
                        if (ms_info.xa_flag)
#endif
                                vol_desc_start = ms_info.addr.lba;
                }
        }

        return vol_desc_start;
}

/*
 * Check if root directory is empty (has less than 3 files).
 *
 * Used to detect broken CDs where ISO root directory is empty but Joliet root
 * directory is OK. If such CD has Rock Ridge extensions, they will be disabled
 * (and Joliet used instead) or else no files would be visible.
 */
static bool rootdir_empty(struct super_block *sb, unsigned long block)
{
        int offset = 0, files = 0, de_len;
        struct iso_directory_record *de;
        struct buffer_head *bh;

        bh = sb_bread(sb, block);
        if (!bh)
                return true;
        while (files < 3) {
                de = (struct iso_directory_record *) (bh->b_data + offset);
                de_len = *(unsigned char *) de;
                if (de_len == 0)
                        break;
                files++;
                offset += de_len;
        }
        brelse(bh);
        return files < 3;
}

/*
 * Initialize the superblock and read the root inode.
 */
static int isofs_fill_super(struct super_block *s, void *data, int silent)
{
        struct buffer_head *bh = NULL, *pri_bh = NULL;
        struct hs_primary_descriptor *h_pri = NULL;
        struct iso_primary_descriptor *pri = NULL;
        struct iso_supplementary_descriptor *sec = NULL;
        struct iso_directory_record *rootp;
        struct inode *inode;
        struct iso9660_options opt;
        struct isofs_sb_info *sbi;
        unsigned long first_data_zone;
        int joliet_level = 0;
        int iso_blknum, block;
        int orig_zonesize;
        int table, error = -EINVAL;
        unsigned int vol_desc_start;

        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
                return -ENOMEM;
        s->s_fs_info = sbi;

        if (!parse_options((char *)data, &opt))
                goto out_freesbi;

        /*
         * First of all, get the hardware blocksize for this device.
         * If we don't know what it is, or the hardware blocksize is
         * larger than the blocksize the user specified, then use
         * that value.
         */
        /*
         * What if bugger tells us to go beyond page size?
         */
        if (bdev_logical_block_size(s->s_bdev) > 2048) {
                printk(KERN_WARNING
                       "ISOFS: unsupported/invalid hardware sector size %d\n",
                        bdev_logical_block_size(s->s_bdev));
                goto out_freesbi;
        }
        opt.blocksize = sb_min_blocksize(s, opt.blocksize);

        sbi->s_high_sierra = 0; /* default is iso9660 */
        sbi->s_session = opt.session;
        sbi->s_sbsector = opt.sbsector;

        vol_desc_start = (opt.sbsector != -1) ?
                opt.sbsector : isofs_get_last_session(s,opt.session);

        for (iso_blknum = vol_desc_start+16;
                iso_blknum < vol_desc_start+100; iso_blknum++) {
                struct hs_volume_descriptor *hdp;
                struct iso_volume_descriptor  *vdp;

                block = iso_blknum << (ISOFS_BLOCK_BITS - s->s_blocksize_bits);
                if (!(bh = sb_bread(s, block)))
                        goto out_no_read;

                vdp = (struct iso_volume_descriptor *)bh->b_data;
                hdp = (struct hs_volume_descriptor *)bh->b_data;

                /*
                 * Due to the overlapping physical location of the descriptors,
                 * ISO CDs can match hdp->id==HS_STANDARD_ID as well. To ensure
                 * proper identification in this case, we first check for ISO.
                 */
                if (strncmp (vdp->id, ISO_STANDARD_ID, sizeof vdp->id) == 0) {
                        if (isonum_711(vdp->type) == ISO_VD_END)
                                break;
                        if (isonum_711(vdp->type) == ISO_VD_PRIMARY) {
                                if (!pri) {
                                        pri = (struct iso_primary_descriptor *)vdp;
                                        /* Save the buffer in case we need it ... */
                                        pri_bh = bh;
                                        bh = NULL;
                                }
                        }
#ifdef CONFIG_JOLIET
                        else if (isonum_711(vdp->type) == ISO_VD_SUPPLEMENTARY) {
                                sec = (struct iso_supplementary_descriptor *)vdp;
                                if (sec->escape[0] == 0x25 && sec->escape[1] == 0x2f) {
                                        if (opt.joliet) {
                                                if (sec->escape[2] == 0x40)
                                                        joliet_level = 1;
                                                else if (sec->escape[2] == 0x43)
                                                        joliet_level = 2;
                                                else if (sec->escape[2] == 0x45)
                                                        joliet_level = 3;

                                                printk(KERN_DEBUG "ISO 9660 Extensions: "
                                                        "Microsoft Joliet Level %d\n",
                                                        joliet_level);
                                        }
                                        goto root_found;
                                } else {
                                /* Unknown supplementary volume descriptor */
                                sec = NULL;
                                }
                        }
#endif
                } else {
                        if (strncmp (hdp->id, HS_STANDARD_ID, sizeof hdp->id) == 0) {
                                if (isonum_711(hdp->type) != ISO_VD_PRIMARY)
                                        goto out_freebh;

                                sbi->s_high_sierra = 1;
                                opt.rock = 0;
                                h_pri = (struct hs_primary_descriptor *)vdp;
                                goto root_found;
                        }
                }

                /* Just skip any volume descriptors we don't recognize */

                brelse(bh);
                bh = NULL;
        }
        /*
         * If we fall through, either no volume descriptor was found,
         * or else we passed a primary descriptor looking for others.
         */
        if (!pri)
                goto out_unknown_format;
        brelse(bh);
        bh = pri_bh;
        pri_bh = NULL;

root_found:
        /* We don't support read-write mounts */
        if (!sb_rdonly(s)) {
                error = -EACCES;
                goto out_freebh;
        }

        if (joliet_level && (!pri || !opt.rock)) {
                /* This is the case of Joliet with the norock mount flag.
                 * A disc with both Joliet and Rock Ridge is handled later
                 */
                pri = (struct iso_primary_descriptor *) sec;
        }

        if(sbi->s_high_sierra){
                rootp = (struct iso_directory_record *) h_pri->root_directory_record;
                sbi->s_nzones = isonum_733(h_pri->volume_space_size);
                sbi->s_log_zone_size = isonum_723(h_pri->logical_block_size);
                sbi->s_max_size = isonum_733(h_pri->volume_space_size);
        } else {
                if (!pri)
                        goto out_freebh;
                rootp = (struct iso_directory_record *) pri->root_directory_record;
                sbi->s_nzones = isonum_733(pri->volume_space_size);
                sbi->s_log_zone_size = isonum_723(pri->logical_block_size);
                sbi->s_max_size = isonum_733(pri->volume_space_size);
        }

        sbi->s_ninodes = 0; /* No way to figure this out easily */

        orig_zonesize = sbi->s_log_zone_size;
        /*
         * If the zone size is smaller than the hardware sector size,
         * this is a fatal error.  This would occur if the disc drive
         * had sectors that were 2048 bytes, but the filesystem had
         * blocks that were 512 bytes (which should only very rarely
         * happen.)
         */
        if (orig_zonesize < opt.blocksize)
                goto out_bad_size;

        /* RDE: convert log zone size to bit shift */
        switch (sbi->s_log_zone_size) {
        case  512: sbi->s_log_zone_size =  9; break;
        case 1024: sbi->s_log_zone_size = 10; break;
        case 2048: sbi->s_log_zone_size = 11; break;

        default:
                goto out_bad_zone_size;
        }

        s->s_magic = ISOFS_SUPER_MAGIC;

        /*
         * With multi-extent files, file size is only limited by the maximum
         * size of a file system, which is 8 TB.
         */
        s->s_maxbytes = 0x80000000000LL;

        /* ECMA-119 timestamp from 1900/1/1 with tz offset */
        s->s_time_min = mktime64(1900, 1, 1, 0, 0, 0) - MAX_TZ_OFFSET;
        s->s_time_max = mktime64(U8_MAX+1900, 12, 31, 23, 59, 59) + MAX_TZ_OFFSET;

        /* Set this for reference. Its not currently used except on write
           which we don't have .. */

        first_data_zone = isonum_733(rootp->extent) +
                          isonum_711(rootp->ext_attr_length);
        sbi->s_firstdatazone = first_data_zone;
#ifndef BEQUIET
        printk(KERN_DEBUG "ISOFS: Max size:%ld   Log zone size:%ld\n",
                sbi->s_max_size, 1UL << sbi->s_log_zone_size);
        printk(KERN_DEBUG "ISOFS: First datazone:%ld\n", sbi->s_firstdatazone);
        if(sbi->s_high_sierra)
                printk(KERN_DEBUG "ISOFS: Disc in High Sierra format.\n");
#endif

        /*
         * If the Joliet level is set, we _may_ decide to use the
         * secondary descriptor, but can't be sure until after we
         * read the root inode. But before reading the root inode
         * we may need to change the device blocksize, and would
         * rather release the old buffer first. So, we cache the
         * first_data_zone value from the secondary descriptor.
         */
        if (joliet_level) {
                pri = (struct iso_primary_descriptor *) sec;
                rootp = (struct iso_directory_record *)
                        pri->root_directory_record;
                first_data_zone = isonum_733(rootp->extent) +
                                isonum_711(rootp->ext_attr_length);
        }

        /*
         * We're all done using the volume descriptor, and may need
         * to change the device blocksize, so release the buffer now.
         */
        brelse(pri_bh);
        brelse(bh);

        /*
         * Force the blocksize to 512 for 512 byte sectors.  The file
         * read primitives really get it wrong in a bad way if we don't
         * do this.
         *
         * Note - we should never be setting the blocksize to something
         * less than the hardware sector size for the device.  If we
         * do, we would end up having to read larger buffers and split
         * out portions to satisfy requests.
         *
         * Note2- the idea here is that we want to deal with the optimal
         * zonesize in the filesystem.  If we have it set to something less,
         * then we have horrible problems with trying to piece together
         * bits of adjacent blocks in order to properly read directory
         * entries.  By forcing the blocksize in this way, we ensure
         * that we will never be required to do this.
         */
        sb_set_blocksize(s, orig_zonesize);

        sbi->s_nls_iocharset = NULL;

#ifdef CONFIG_JOLIET
        if (joliet_level && opt.utf8 == 0) {
                char *p = opt.iocharset ? opt.iocharset : CONFIG_NLS_DEFAULT;
                sbi->s_nls_iocharset = load_nls(p);
                if (! sbi->s_nls_iocharset) {
                        /* Fail only if explicit charset specified */
                        if (opt.iocharset)
                                goto out_freesbi;
                        sbi->s_nls_iocharset = load_nls_default();
                }
        }
#endif
        s->s_op = &isofs_sops;
        s->s_export_op = &isofs_export_ops;
        sbi->s_mapping = opt.map;
        sbi->s_rock = (opt.rock ? 2 : 0);
        sbi->s_rock_offset = -1; /* initial offset, will guess until SP is found*/
        sbi->s_cruft = opt.cruft;
        sbi->s_hide = opt.hide;
        sbi->s_showassoc = opt.showassoc;
        sbi->s_uid = opt.uid;
        sbi->s_gid = opt.gid;
        sbi->s_uid_set = opt.uid_set;
        sbi->s_gid_set = opt.gid_set;
        sbi->s_utf8 = opt.utf8;
        sbi->s_nocompress = opt.nocompress;
        sbi->s_overriderockperm = opt.overriderockperm;
        /*
         * It would be incredibly stupid to allow people to mark every file
         * on the disk as suid, so we merely allow them to set the default
         * permissions.
         */
        if (opt.fmode != ISOFS_INVALID_MODE)
                sbi->s_fmode = opt.fmode & 0777;
        else
                sbi->s_fmode = ISOFS_INVALID_MODE;
        if (opt.dmode != ISOFS_INVALID_MODE)
                sbi->s_dmode = opt.dmode & 0777;
        else
                sbi->s_dmode = ISOFS_INVALID_MODE;

        /*
         * Read the root inode, which _may_ result in changing
         * the s_rock flag. Once we have the final s_rock value,
         * we then decide whether to use the Joliet descriptor.
         */
        inode = isofs_iget(s, sbi->s_firstdatazone, 0);
        if (IS_ERR(inode))
                goto out_no_root;

        /*
         * Fix for broken CDs with Rock Ridge and empty ISO root directory but
         * correct Joliet root directory.
         */
        if (sbi->s_rock == 1 && joliet_level &&
                                rootdir_empty(s, sbi->s_firstdatazone)) {
                printk(KERN_NOTICE
                        "ISOFS: primary root directory is empty. "
                        "Disabling Rock Ridge and switching to Joliet.");
                sbi->s_rock = 0;
        }

        /*
         * If this disk has both Rock Ridge and Joliet on it, then we
         * want to use Rock Ridge by default.  This can be overridden
         * by using the norock mount option.  There is still one other
         * possibility that is not taken into account: a Rock Ridge
         * CD with Unicode names.  Until someone sees such a beast, it
         * will not be supported.
         */
        if (sbi->s_rock == 1) {
                joliet_level = 0;
        } else if (joliet_level) {
                sbi->s_rock = 0;
                if (sbi->s_firstdatazone != first_data_zone) {
                        sbi->s_firstdatazone = first_data_zone;
                        printk(KERN_DEBUG
                                "ISOFS: changing to secondary root\n");
                        iput(inode);
                        inode = isofs_iget(s, sbi->s_firstdatazone, 0);
                        if (IS_ERR(inode))
                                goto out_no_root;
                }
        }

        if (opt.check == 'u') {
                /* Only Joliet is case insensitive by default */
                if (joliet_level)
                        opt.check = 'r';
                else
                        opt.check = 's';
        }
        sbi->s_joliet_level = joliet_level;

        /* Make sure the root inode is a directory */
        if (!S_ISDIR(inode->i_mode)) {
                printk(KERN_WARNING
                        "isofs_fill_super: root inode is not a directory. "
                        "Corrupted media?\n");
                goto out_iput;
        }

        table = 0;
        if (joliet_level)
                table += 2;
        if (opt.check == 'r')
                table++;
        sbi->s_check = opt.check;

        if (table)
                s->s_d_op = &isofs_dentry_ops[table - 1];

        /* get the root dentry */
        s->s_root = d_make_root(inode);
        if (!(s->s_root)) {
                error = -ENOMEM;
                goto out_no_inode;
        }

        kfree(opt.iocharset);

        return 0;

        /*
         * Display error messages and free resources.
         */
out_iput:
        iput(inode);
        goto out_no_inode;
out_no_root:
        error = PTR_ERR(inode);
        if (error != -ENOMEM)
                printk(KERN_WARNING "%s: get root inode failed\n", __func__);
out_no_inode:
#ifdef CONFIG_JOLIET
        unload_nls(sbi->s_nls_iocharset);

#endif
        goto out_freesbi;
out_no_read:
        printk(KERN_WARNING "%s: bread failed, dev=%s, iso_blknum=%d, block=%d\n",
                __func__, s->s_id, iso_blknum, block);
        goto out_freebh;
out_bad_zone_size:
        printk(KERN_WARNING "ISOFS: Bad logical zone size %ld\n",
                sbi->s_log_zone_size);
        goto out_freebh;
out_bad_size:
        printk(KERN_WARNING "ISOFS: Logical zone size(%d) < hardware blocksize(%u)\n",
                orig_zonesize, opt.blocksize);
        goto out_freebh;
out_unknown_format:
        if (!silent)
                printk(KERN_WARNING "ISOFS: Unable to identify CD-ROM format.\n");

out_freebh:
        brelse(bh);
        brelse(pri_bh);
out_freesbi:
        kfree(opt.iocharset);
        kfree(sbi);
        s->s_fs_info = NULL;
        return error;
}

static int isofs_statfs (struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

        buf->f_type = ISOFS_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = (ISOFS_SB(sb)->s_nzones
                << (ISOFS_SB(sb)->s_log_zone_size - sb->s_blocksize_bits));
        buf->f_bfree = 0;
        buf->f_bavail = 0;
        buf->f_files = ISOFS_SB(sb)->s_ninodes;
        buf->f_ffree = 0;
        buf->f_fsid = u64_to_fsid(id);
        buf->f_namelen = NAME_MAX;
        return 0;
}

/*
 * Get a set of blocks; filling in buffer_heads if already allocated
 * or getblk() if they are not.  Returns the number of blocks inserted
 * (-ve == error.)
 */
int isofs_get_blocks(struct inode *inode, sector_t iblock,
                     struct buffer_head **bh, unsigned long nblocks)
{
        unsigned long b_off = iblock;
        unsigned offset, sect_size;
        unsigned int firstext;
        unsigned long nextblk, nextoff;
        int section, rv, error;
        struct iso_inode_info *ei = ISOFS_I(inode);

        error = -EIO;
        rv = 0;
        if (iblock != b_off) {
                printk(KERN_DEBUG "%s: block number too large\n", __func__);
                goto abort;
        }


        offset = 0;
        firstext = ei->i_first_extent;
        sect_size = ei->i_section_size >> ISOFS_BUFFER_BITS(inode);
        nextblk = ei->i_next_section_block;
        nextoff = ei->i_next_section_offset;
        section = 0;

        while (nblocks) {
                /* If we are *way* beyond the end of the file, print a message.
                 * Access beyond the end of the file up to the next page boundary
                 * is normal, however because of the way the page cache works.
                 * In this case, we just return 0 so that we can properly fill
                 * the page with useless information without generating any
                 * I/O errors.
                 */
                if (b_off > ((inode->i_size + PAGE_SIZE - 1) >> ISOFS_BUFFER_BITS(inode))) {
                        printk(KERN_DEBUG "%s: block >= EOF (%lu, %llu)\n",
                                __func__, b_off,
                                (unsigned long long)inode->i_size);
                        goto abort;
                }

                /* On the last section, nextblk == 0, section size is likely to
                 * exceed sect_size by a partial block, and access beyond the
                 * end of the file will reach beyond the section size, too.
                 */
                while (nextblk && (b_off >= (offset + sect_size))) {
                        struct inode *ninode;

                        offset += sect_size;
                        ninode = isofs_iget(inode->i_sb, nextblk, nextoff);
                        if (IS_ERR(ninode)) {
                                error = PTR_ERR(ninode);
                                goto abort;
                        }
                        firstext  = ISOFS_I(ninode)->i_first_extent;
                        sect_size = ISOFS_I(ninode)->i_section_size >> ISOFS_BUFFER_BITS(ninode);
                        nextblk   = ISOFS_I(ninode)->i_next_section_block;
                        nextoff   = ISOFS_I(ninode)->i_next_section_offset;
                        iput(ninode);

                        if (++section > 100) {
                                printk(KERN_DEBUG "%s: More than 100 file sections ?!?"
                                        " aborting...\n", __func__);
                                printk(KERN_DEBUG "%s: block=%lu firstext=%u sect_size=%u "
                                        "nextblk=%lu nextoff=%lu\n", __func__,
                                        b_off, firstext, (unsigned) sect_size,
                                        nextblk, nextoff);
                                goto abort;
                        }
                }

                if (*bh) {
                        map_bh(*bh, inode->i_sb, firstext + b_off - offset);
                } else {
                        *bh = sb_getblk(inode->i_sb, firstext+b_off-offset);
                        if (!*bh)
                                goto abort;
                }
                bh++;   /* Next buffer head */
                b_off++;        /* Next buffer offset */
                nblocks--;
                rv++;
        }

        error = 0;
abort:
        return rv != 0 ? rv : error;
}

/*
 * Used by the standard interfaces.
 */
static int isofs_get_block(struct inode *inode, sector_t iblock,
                    struct buffer_head *bh_result, int create)
{
        int ret;

        if (create) {
                printk(KERN_DEBUG "%s: Kernel tries to allocate a block\n", __func__);
                return -EROFS;
        }

        ret = isofs_get_blocks(inode, iblock, &bh_result, 1);
        return ret < 0 ? ret : 0;
}

static int isofs_bmap(struct inode *inode, sector_t block)
{
        struct buffer_head dummy;
        int error;

        dummy.b_state = 0;
        dummy.b_blocknr = -1000;
        error = isofs_get_block(inode, block, &dummy, 0);
        if (!error)
                return dummy.b_blocknr;
        return 0;
}

struct buffer_head *isofs_bread(struct inode *inode, sector_t block)
{
        sector_t blknr = isofs_bmap(inode, block);
        if (!blknr)
                return NULL;
        return sb_bread(inode->i_sb, blknr);
}

static int isofs_readpage(struct file *file, struct page *page)
{
        return mpage_readpage(page, isofs_get_block);
}

static void isofs_readahead(struct readahead_control *rac)
{
        mpage_readahead(rac, isofs_get_block);
}

static sector_t _isofs_bmap(struct address_space *mapping, sector_t block)
{
        return generic_block_bmap(mapping,block,isofs_get_block);
}

static const struct address_space_operations isofs_aops = {
        .readpage = isofs_readpage,
        .readahead = isofs_readahead,
        .bmap = _isofs_bmap
};

static int isofs_read_level3_size(struct inode *inode)
{
        unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
        int high_sierra = ISOFS_SB(inode->i_sb)->s_high_sierra;
        struct buffer_head *bh = NULL;
        unsigned long block, offset, block_saved, offset_saved;
        int i = 0;
        int more_entries = 0;
        struct iso_directory_record *tmpde = NULL;
        struct iso_inode_info *ei = ISOFS_I(inode);

        inode->i_size = 0;

        /* The first 16 blocks are reserved as the System Area.  Thus,
         * no inodes can appear in block 0.  We use this to flag that
         * this is the last section. */
        ei->i_next_section_block = 0;
        ei->i_next_section_offset = 0;

        block = ei->i_iget5_block;
        offset = ei->i_iget5_offset;

        do {
                struct iso_directory_record *de;
                unsigned int de_len;

                if (!bh) {
                        bh = sb_bread(inode->i_sb, block);
                        if (!bh)
                                goto out_noread;
                }
                de = (struct iso_directory_record *) (bh->b_data + offset);
                de_len = *(unsigned char *) de;

                if (de_len == 0) {
                        brelse(bh);
                        bh = NULL;
                        ++block;
                        offset = 0;
                        continue;
                }

                block_saved = block;
                offset_saved = offset;
                offset += de_len;

                /* Make sure we have a full directory entry */
                if (offset >= bufsize) {
                        int slop = bufsize - offset + de_len;
                        if (!tmpde) {
                                tmpde = kmalloc(256, GFP_KERNEL);
                                if (!tmpde)
                                        goto out_nomem;
                        }
                        memcpy(tmpde, de, slop);
                        offset &= bufsize - 1;
                        block++;
                        brelse(bh);
                        bh = NULL;
                        if (offset) {
                                bh = sb_bread(inode->i_sb, block);
                                if (!bh)
                                        goto out_noread;
                                memcpy((void *)tmpde+slop, bh->b_data, offset);
                        }
                        de = tmpde;
                }

                inode->i_size += isonum_733(de->size);
                if (i == 1) {
                        ei->i_next_section_block = block_saved;
                        ei->i_next_section_offset = offset_saved;
                }

                more_entries = de->flags[-high_sierra] & 0x80;

                i++;
                if (i > 100)
                        goto out_toomany;
        } while (more_entries);
out:
        kfree(tmpde);
        if (bh)
                brelse(bh);
        return 0;

out_nomem:
        if (bh)
                brelse(bh);
        return -ENOMEM;

out_noread:
        printk(KERN_INFO "ISOFS: unable to read i-node block %lu\n", block);
        kfree(tmpde);
        return -EIO;

out_toomany:
        printk(KERN_INFO "%s: More than 100 file sections ?!?, aborting...\n"
                "isofs_read_level3_size: inode=%lu\n",
                __func__, inode->i_ino);
        goto out;
}

static int isofs_read_inode(struct inode *inode, int relocated)
{
        struct super_block *sb = inode->i_sb;
        struct isofs_sb_info *sbi = ISOFS_SB(sb);
        unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
        unsigned long block;
        int high_sierra = sbi->s_high_sierra;
        struct buffer_head *bh;
        struct iso_directory_record *de;
        struct iso_directory_record *tmpde = NULL;
        unsigned int de_len;
        unsigned long offset;
        struct iso_inode_info *ei = ISOFS_I(inode);
        int ret = -EIO;

        block = ei->i_iget5_block;
        bh = sb_bread(inode->i_sb, block);
        if (!bh)
                goto out_badread;

        offset = ei->i_iget5_offset;

        de = (struct iso_directory_record *) (bh->b_data + offset);
        de_len = *(unsigned char *) de;

        if (offset + de_len > bufsize) {
                int frag1 = bufsize - offset;

                tmpde = kmalloc(de_len, GFP_KERNEL);
                if (!tmpde) {
                        ret = -ENOMEM;
                        goto fail;
                }
                memcpy(tmpde, bh->b_data + offset, frag1);
                brelse(bh);
                bh = sb_bread(inode->i_sb, ++block);
                if (!bh)
                        goto out_badread;
                memcpy((char *)tmpde+frag1, bh->b_data, de_len - frag1);
                de = tmpde;
        }

        inode->i_ino = isofs_get_ino(ei->i_iget5_block,
                                        ei->i_iget5_offset,
                                        ISOFS_BUFFER_BITS(inode));

        /* Assume it is a normal-format file unless told otherwise */
        ei->i_file_format = isofs_file_normal;

        if (de->flags[-high_sierra] & 2) {
                if (sbi->s_dmode != ISOFS_INVALID_MODE)
                        inode->i_mode = S_IFDIR | sbi->s_dmode;
                else
                        inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
                set_nlink(inode, 1);    /*
                                         * Set to 1.  We know there are 2, but
                                         * the find utility tries to optimize
                                         * if it is 2, and it screws up.  It is
                                         * easier to give 1 which tells find to
                                         * do it the hard way.
                                         */
        } else {
                if (sbi->s_fmode != ISOFS_INVALID_MODE) {
                        inode->i_mode = S_IFREG | sbi->s_fmode;
                } else {
                        /*
                         * Set default permissions: r-x for all.  The disc
                         * could be shared with DOS machines so virtually
                         * anything could be a valid executable.
                         */
                        inode->i_mode = S_IFREG | S_IRUGO | S_IXUGO;
                }
                set_nlink(inode, 1);
        }
        inode->i_uid = sbi->s_uid;
        inode->i_gid = sbi->s_gid;
        inode->i_blocks = 0;

        ei->i_format_parm[0] = 0;
        ei->i_format_parm[1] = 0;
        ei->i_format_parm[2] = 0;

        ei->i_section_size = isonum_733(de->size);
        if (de->flags[-high_sierra] & 0x80) {
                ret = isofs_read_level3_size(inode);
                if (ret < 0)
                        goto fail;
                ret = -EIO;
        } else {
                ei->i_next_section_block = 0;
                ei->i_next_section_offset = 0;
                inode->i_size = isonum_733(de->size);
        }

        /*
         * Some dipshit decided to store some other bit of information
         * in the high byte of the file length.  Truncate size in case
         * this CDROM was mounted with the cruft option.
         */

        if (sbi->s_cruft)
                inode->i_size &= 0x00ffffff;

        if (de->interleave[0]) {
                printk(KERN_DEBUG "ISOFS: Interleaved files not (yet) supported.\n");
                inode->i_size = 0;
        }

        /* I have no idea what file_unit_size is used for, so
           we will flag it for now */
        if (de->file_unit_size[0] != 0) {
                printk(KERN_DEBUG "ISOFS: File unit size != 0 for ISO file (%ld).\n",
                        inode->i_ino);
        }

        /* I have no idea what other flag bits are used for, so
           we will flag it for now */
#ifdef DEBUG
        if((de->flags[-high_sierra] & ~2)!= 0){
                printk(KERN_DEBUG "ISOFS: Unusual flag settings for ISO file "
                                "(%ld %x).\n",
                        inode->i_ino, de->flags[-high_sierra]);
        }
#endif

        inode->i_mtime.tv_sec =
        inode->i_atime.tv_sec =
        inode->i_ctime.tv_sec = iso_date(de->date, high_sierra);
        inode->i_mtime.tv_nsec =
        inode->i_atime.tv_nsec =
        inode->i_ctime.tv_nsec = 0;

        ei->i_first_extent = (isonum_733(de->extent) +
                        isonum_711(de->ext_attr_length));

        /* Set the number of blocks for stat() - should be done before RR */
        inode->i_blocks = (inode->i_size + 511) >> 9;

        /*
         * Now test for possible Rock Ridge extensions which will override
         * some of these numbers in the inode structure.
         */

        if (!high_sierra) {
                parse_rock_ridge_inode(de, inode, relocated);
                /* if we want uid/gid set, override the rock ridge setting */
                if (sbi->s_uid_set)
                        inode->i_uid = sbi->s_uid;
                if (sbi->s_gid_set)
                        inode->i_gid = sbi->s_gid;
        }
        /* Now set final access rights if overriding rock ridge setting */
        if (S_ISDIR(inode->i_mode) && sbi->s_overriderockperm &&
            sbi->s_dmode != ISOFS_INVALID_MODE)
                inode->i_mode = S_IFDIR | sbi->s_dmode;
        if (S_ISREG(inode->i_mode) && sbi->s_overriderockperm &&
            sbi->s_fmode != ISOFS_INVALID_MODE)
                inode->i_mode = S_IFREG | sbi->s_fmode;

        /* Install the inode operations vector */
        if (S_ISREG(inode->i_mode)) {
                inode->i_fop = &generic_ro_fops;
                switch (ei->i_file_format) {
#ifdef CONFIG_ZISOFS
                case isofs_file_compressed:
                        inode->i_data.a_ops = &zisofs_aops;
                        break;
#endif
                default:
                        inode->i_data.a_ops = &isofs_aops;
                        break;
                }
        } else if (S_ISDIR(inode->i_mode)) {
                inode->i_op = &isofs_dir_inode_operations;
                inode->i_fop = &isofs_dir_operations;
        } else if (S_ISLNK(inode->i_mode)) {
                inode->i_op = &page_symlink_inode_operations;
                inode_nohighmem(inode);
                inode->i_data.a_ops = &isofs_symlink_aops;
        } else
                /* XXX - parse_rock_ridge_inode() had already set i_rdev. */
                init_special_inode(inode, inode->i_mode, inode->i_rdev);

        ret = 0;
out:
        kfree(tmpde);
        if (bh)
                brelse(bh);
        return ret;

out_badread:
        printk(KERN_WARNING "ISOFS: unable to read i-node block\n");
fail:
        goto out;
}

struct isofs_iget5_callback_data {
        unsigned long block;
        unsigned long offset;
};

static int isofs_iget5_test(struct inode *ino, void *data)
{
        struct iso_inode_info *i = ISOFS_I(ino);
        struct isofs_iget5_callback_data *d =
                (struct isofs_iget5_callback_data*)data;
        return (i->i_iget5_block == d->block)
                && (i->i_iget5_offset == d->offset);
}

static int isofs_iget5_set(struct inode *ino, void *data)
{
        struct iso_inode_info *i = ISOFS_I(ino);
        struct isofs_iget5_callback_data *d =
                (struct isofs_iget5_callback_data*)data;
        i->i_iget5_block = d->block;
        i->i_iget5_offset = d->offset;
        return 0;
}

/* Store, in the inode's containing structure, the block and block
 * offset that point to the underlying meta-data for the inode.  The
 * code below is otherwise similar to the iget() code in
 * include/linux/fs.h */
struct inode *__isofs_iget(struct super_block *sb,
                           unsigned long block,
                           unsigned long offset,
                           int relocated)
{
        unsigned long hashval;
        struct inode *inode;
        struct isofs_iget5_callback_data data;
        long ret;

        if (offset >= 1ul << sb->s_blocksize_bits)
                return ERR_PTR(-EINVAL);

        data.block = block;
        data.offset = offset;

        hashval = (block << sb->s_blocksize_bits) | offset;

        inode = iget5_locked(sb, hashval, &isofs_iget5_test,
                                &isofs_iget5_set, &data);

        if (!inode)
                return ERR_PTR(-ENOMEM);

        if (inode->i_state & I_NEW) {
                ret = isofs_read_inode(inode, relocated);
                if (ret < 0) {
                        iget_failed(inode);
                        inode = ERR_PTR(ret);
                } else {
                        unlock_new_inode(inode);
                }
        }

        return inode;
}

static struct dentry *isofs_mount(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, isofs_fill_super);
}

static struct file_system_type iso9660_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "iso9660",
        .mount          = isofs_mount,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("iso9660");
MODULE_ALIAS("iso9660");

static int __init init_iso9660_fs(void)
{
        int err = init_inodecache();
        if (err)
                goto out;
#ifdef CONFIG_ZISOFS
        err = zisofs_init();
        if (err)
                goto out1;
#endif
        err = register_filesystem(&iso9660_fs_type);
        if (err)
                goto out2;
        return 0;
out2:
#ifdef CONFIG_ZISOFS
        zisofs_cleanup();
out1:
#endif
        destroy_inodecache();
out:
        return err;
}

static void __exit exit_iso9660_fs(void)
{
        unregister_filesystem(&iso9660_fs_type);
#ifdef CONFIG_ZISOFS
        zisofs_cleanup();
#endif
        destroy_inodecache();
}

module_init(init_iso9660_fs)
module_exit(exit_iso9660_fs)
MODULE_LICENSE("GPL");