/*
 * super.c
 *
 * PURPOSE
 *  Super block routines for the OSTA-UDF(tm) filesystem.
 *
 * DESCRIPTION
 *  OSTA-UDF(tm) = Optical Storage Technology Association
 *  Universal Disk Format.
 *
 *  This code is based on version 2.00 of the UDF specification,
 *  and revision 3 of the ECMA 167 standard [equivalent to ISO 13346].
 *    http://www.osta.org/
 *    https://www.ecma.ch/
 *    https://www.iso.org/
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *    ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998 Dave Boynton
 *  (C) 1998-2004 Ben Fennema
 *  (C) 2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  09/24/98 dgb  changed to allow compiling outside of kernel, and
 *                added some debugging.
 *  10/01/98 dgb  updated to allow (some) possibility of compiling w/2.0.34
 *  10/16/98      attempting some multi-session support
 *  10/17/98      added freespace count for "df"
 *  11/11/98 gr   added novrs option
 *  11/26/98 dgb  added fileset,anchor mount options
 *  12/06/98 blf  really hosed things royally. vat/sparing support. sequenced
 *                vol descs. rewrote option handling based on isofs
 *  12/20/98      find the free space bitmap (if it exists)
 */

#include "udfdecl.h"

#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/stat.h>
#include <linux/cdrom.h>
#include <linux/nls.h>
#include <linux/vfs.h>
#include <linux/vmalloc.h>
#include <linux/errno.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/bitmap.h>
#include <linux/crc-itu-t.h>
#include <linux/log2.h>
#include <asm/byteorder.h>

#include "udf_sb.h"
#include "udf_i.h"

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

enum {
        VDS_POS_PRIMARY_VOL_DESC,
        VDS_POS_UNALLOC_SPACE_DESC,
        VDS_POS_LOGICAL_VOL_DESC,
        VDS_POS_IMP_USE_VOL_DESC,
        VDS_POS_LENGTH
};

#define VSD_FIRST_SECTOR_OFFSET         32768
#define VSD_MAX_SECTOR_OFFSET           0x800000

/*
 * Maximum number of Terminating Descriptor / Logical Volume Integrity
 * Descriptor redirections. The chosen numbers are arbitrary - just that we
 * hopefully don't limit any real use of rewritten inode on write-once media
 * but avoid looping for too long on corrupted media.
 */
#define UDF_MAX_TD_NESTING 64
#define UDF_MAX_LVID_NESTING 1000

enum { UDF_MAX_LINKS = 0xffff };

/* These are the "meat" - everything else is stuffing */
static int udf_fill_super(struct super_block *, void *, int);
static void udf_put_super(struct super_block *);
static int udf_sync_fs(struct super_block *, int);
static int udf_remount_fs(struct super_block *, int *, char *);
static void udf_load_logicalvolint(struct super_block *, struct kernel_extent_ad);
static void udf_open_lvid(struct super_block *);
static void udf_close_lvid(struct super_block *);
static unsigned int udf_count_free(struct super_block *);
static int udf_statfs(struct dentry *, struct kstatfs *);
static int udf_show_options(struct seq_file *, struct dentry *);

struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct super_block *sb)
{
        struct logicalVolIntegrityDesc *lvid;
        unsigned int partnum;
        unsigned int offset;

        if (!UDF_SB(sb)->s_lvid_bh)
                return NULL;
        lvid = (struct logicalVolIntegrityDesc *)UDF_SB(sb)->s_lvid_bh->b_data;
        partnum = le32_to_cpu(lvid->numOfPartitions);
        if ((sb->s_blocksize - sizeof(struct logicalVolIntegrityDescImpUse) -
             offsetof(struct logicalVolIntegrityDesc, impUse)) /
             (2 * sizeof(uint32_t)) < partnum) {
                udf_err(sb, "Logical volume integrity descriptor corrupted "
                        "(numOfPartitions = %u)!\n", partnum);
                return NULL;
        }
        /* The offset is to skip freeSpaceTable and sizeTable arrays */
        offset = partnum * 2 * sizeof(uint32_t);
        return (struct logicalVolIntegrityDescImpUse *)&(lvid->impUse[offset]);
}

/* UDF filesystem type */
static struct dentry *udf_mount(struct file_system_type *fs_type,
                      int flags, const char *dev_name, void *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, udf_fill_super);
}

static struct file_system_type udf_fstype = {
        .owner          = THIS_MODULE,
        .name           = "udf",
        .mount          = udf_mount,
        .kill_sb        = kill_block_super,
        .fs_flags       = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("udf");

static struct kmem_cache *udf_inode_cachep;

static struct inode *udf_alloc_inode(struct super_block *sb)
{
        struct udf_inode_info *ei;
        ei = kmem_cache_alloc(udf_inode_cachep, GFP_KERNEL);
        if (!ei)
                return NULL;

        ei->i_unique = 0;
        ei->i_lenExtents = 0;
        ei->i_lenStreams = 0;
        ei->i_next_alloc_block = 0;
        ei->i_next_alloc_goal = 0;
        ei->i_strat4096 = 0;
        ei->i_streamdir = 0;
        init_rwsem(&ei->i_data_sem);
        ei->cached_extent.lstart = -1;
        spin_lock_init(&ei->i_extent_cache_lock);

        return &ei->vfs_inode;
}

static void udf_free_in_core_inode(struct inode *inode)
{
        kmem_cache_free(udf_inode_cachep, UDF_I(inode));
}

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

        ei->i_data = NULL;
        inode_init_once(&ei->vfs_inode);
}

static int __init init_inodecache(void)
{
        udf_inode_cachep = kmem_cache_create("udf_inode_cache",
                                             sizeof(struct udf_inode_info),
                                             0, (SLAB_RECLAIM_ACCOUNT |
                                                 SLAB_MEM_SPREAD |
                                                 SLAB_ACCOUNT),
                                             init_once);
        if (!udf_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(udf_inode_cachep);
}

/* Superblock operations */
static const struct super_operations udf_sb_ops = {
        .alloc_inode    = udf_alloc_inode,
        .free_inode     = udf_free_in_core_inode,
        .write_inode    = udf_write_inode,
        .evict_inode    = udf_evict_inode,
        .put_super      = udf_put_super,
        .sync_fs        = udf_sync_fs,
        .statfs         = udf_statfs,
        .remount_fs     = udf_remount_fs,
        .show_options   = udf_show_options,
};

struct udf_options {
        unsigned char novrs;
        unsigned int blocksize;
        unsigned int session;
        unsigned int lastblock;
        unsigned int anchor;
        unsigned int flags;
        umode_t umask;
        kgid_t gid;
        kuid_t uid;
        umode_t fmode;
        umode_t dmode;
        struct nls_table *nls_map;
};

static int __init init_udf_fs(void)
{
        int err;

        err = init_inodecache();
        if (err)
                goto out1;
        err = register_filesystem(&udf_fstype);
        if (err)
                goto out;

        return 0;

out:
        destroy_inodecache();

out1:
        return err;
}

static void __exit exit_udf_fs(void)
{
        unregister_filesystem(&udf_fstype);
        destroy_inodecache();
}

static int udf_sb_alloc_partition_maps(struct super_block *sb, u32 count)
{
        struct udf_sb_info *sbi = UDF_SB(sb);

        sbi->s_partmaps = kcalloc(count, sizeof(*sbi->s_partmaps), GFP_KERNEL);
        if (!sbi->s_partmaps) {
                sbi->s_partitions = 0;
                return -ENOMEM;
        }

        sbi->s_partitions = count;
        return 0;
}

static void udf_sb_free_bitmap(struct udf_bitmap *bitmap)
{
        int i;
        int nr_groups = bitmap->s_nr_groups;

        for (i = 0; i < nr_groups; i++)
                brelse(bitmap->s_block_bitmap[i]);

        kvfree(bitmap);
}

static void udf_free_partition(struct udf_part_map *map)
{
        int i;
        struct udf_meta_data *mdata;

        if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
                iput(map->s_uspace.s_table);
        if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP)
                udf_sb_free_bitmap(map->s_uspace.s_bitmap);
        if (map->s_partition_type == UDF_SPARABLE_MAP15)
                for (i = 0; i < 4; i++)
                        brelse(map->s_type_specific.s_sparing.s_spar_map[i]);
        else if (map->s_partition_type == UDF_METADATA_MAP25) {
                mdata = &map->s_type_specific.s_metadata;
                iput(mdata->s_metadata_fe);
                mdata->s_metadata_fe = NULL;

                iput(mdata->s_mirror_fe);
                mdata->s_mirror_fe = NULL;

                iput(mdata->s_bitmap_fe);
                mdata->s_bitmap_fe = NULL;
        }
}

static void udf_sb_free_partitions(struct super_block *sb)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        int i;

        if (!sbi->s_partmaps)
                return;
        for (i = 0; i < sbi->s_partitions; i++)
                udf_free_partition(&sbi->s_partmaps[i]);
        kfree(sbi->s_partmaps);
        sbi->s_partmaps = NULL;
}

static int udf_show_options(struct seq_file *seq, struct dentry *root)
{
        struct super_block *sb = root->d_sb;
        struct udf_sb_info *sbi = UDF_SB(sb);

        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT))
                seq_puts(seq, ",nostrict");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_BLOCKSIZE_SET))
                seq_printf(seq, ",bs=%lu", sb->s_blocksize);
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
                seq_puts(seq, ",unhide");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
                seq_puts(seq, ",undelete");
        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_USE_AD_IN_ICB))
                seq_puts(seq, ",noadinicb");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_USE_SHORT_AD))
                seq_puts(seq, ",shortad");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_UID_FORGET))
                seq_puts(seq, ",uid=forget");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_GID_FORGET))
                seq_puts(seq, ",gid=forget");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET))
                seq_printf(seq, ",uid=%u", from_kuid(&init_user_ns, sbi->s_uid));
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET))
                seq_printf(seq, ",gid=%u", from_kgid(&init_user_ns, sbi->s_gid));
        if (sbi->s_umask != 0)
                seq_printf(seq, ",umask=%ho", sbi->s_umask);
        if (sbi->s_fmode != UDF_INVALID_MODE)
                seq_printf(seq, ",mode=%ho", sbi->s_fmode);
        if (sbi->s_dmode != UDF_INVALID_MODE)
                seq_printf(seq, ",dmode=%ho", sbi->s_dmode);
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_SESSION_SET))
                seq_printf(seq, ",session=%d", sbi->s_session);
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_LASTBLOCK_SET))
                seq_printf(seq, ",lastblock=%u", sbi->s_last_block);
        if (sbi->s_anchor != 0)
                seq_printf(seq, ",anchor=%u", sbi->s_anchor);
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8))
                seq_puts(seq, ",utf8");
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP) && sbi->s_nls_map)
                seq_printf(seq, ",iocharset=%s", sbi->s_nls_map->charset);

        return 0;
}

/*
 * udf_parse_options
 *
 * PURPOSE
 *      Parse mount options.
 *
 * DESCRIPTION
 *      The following mount options are supported:
 *
 *      gid=            Set the default group.
 *      umask=          Set the default umask.
 *      mode=           Set the default file permissions.
 *      dmode=          Set the default directory permissions.
 *      uid=            Set the default user.
 *      bs=             Set the block size.
 *      unhide          Show otherwise hidden files.
 *      undelete        Show deleted files in lists.
 *      adinicb         Embed data in the inode (default)
 *      noadinicb       Don't embed data in the inode
 *      shortad         Use short ad's
 *      longad          Use long ad's (default)
 *      nostrict        Unset strict conformance
 *      iocharset=      Set the NLS character set
 *
 *      The remaining are for debugging and disaster recovery:
 *
 *      novrs           Skip volume sequence recognition
 *
 *      The following expect a offset from 0.
 *
 *      session=        Set the CDROM session (default= last session)
 *      anchor=         Override standard anchor location. (default= 256)
 *      volume=         Override the VolumeDesc location. (unused)
 *      partition=      Override the PartitionDesc location. (unused)
 *      lastblock=      Set the last block of the filesystem/
 *
 *      The following expect a offset from the partition root.
 *
 *      fileset=        Override the fileset block location. (unused)
 *      rootdir=        Override the root directory location. (unused)
 *              WARNING: overriding the rootdir to a non-directory may
 *              yield highly unpredictable results.
 *
 * PRE-CONDITIONS
 *      options         Pointer to mount options string.
 *      uopts           Pointer to mount options variable.
 *
 * POST-CONDITIONS
 *      <return>        1       Mount options parsed okay.
 *      <return>        0       Error parsing mount options.
 *
 * HISTORY
 *      July 1, 1997 - Andrew E. Mileski
 *      Written, tested, and released.
 */

enum {
        Opt_novrs, Opt_nostrict, Opt_bs, Opt_unhide, Opt_undelete,
        Opt_noadinicb, Opt_adinicb, Opt_shortad, Opt_longad,
        Opt_gid, Opt_uid, Opt_umask, Opt_session, Opt_lastblock,
        Opt_anchor, Opt_volume, Opt_partition, Opt_fileset,
        Opt_rootdir, Opt_utf8, Opt_iocharset,
        Opt_err, Opt_uforget, Opt_uignore, Opt_gforget, Opt_gignore,
        Opt_fmode, Opt_dmode
};

static const match_table_t tokens = {
        {Opt_novrs,     "novrs"},
        {Opt_nostrict,  "nostrict"},
        {Opt_bs,        "bs=%u"},
        {Opt_unhide,    "unhide"},
        {Opt_undelete,  "undelete"},
        {Opt_noadinicb, "noadinicb"},
        {Opt_adinicb,   "adinicb"},
        {Opt_shortad,   "shortad"},
        {Opt_longad,    "longad"},
        {Opt_uforget,   "uid=forget"},
        {Opt_uignore,   "uid=ignore"},
        {Opt_gforget,   "gid=forget"},
        {Opt_gignore,   "gid=ignore"},
        {Opt_gid,       "gid=%u"},
        {Opt_uid,       "uid=%u"},
        {Opt_umask,     "umask=%o"},
        {Opt_session,   "session=%u"},
        {Opt_lastblock, "lastblock=%u"},
        {Opt_anchor,    "anchor=%u"},
        {Opt_volume,    "volume=%u"},
        {Opt_partition, "partition=%u"},
        {Opt_fileset,   "fileset=%u"},
        {Opt_rootdir,   "rootdir=%u"},
        {Opt_utf8,      "utf8"},
        {Opt_iocharset, "iocharset=%s"},
        {Opt_fmode,     "mode=%o"},
        {Opt_dmode,     "dmode=%o"},
        {Opt_err,       NULL}
};

static int udf_parse_options(char *options, struct udf_options *uopt,
                             bool remount)
{
        char *p;
        int option;
        unsigned int uv;

        uopt->novrs = 0;
        uopt->session = 0xFFFFFFFF;
        uopt->lastblock = 0;
        uopt->anchor = 0;

        if (!options)
                return 1;

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

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_novrs:
                        uopt->novrs = 1;
                        break;
                case Opt_bs:
                        if (match_int(&args[0], &option))
                                return 0;
                        n = option;
                        if (n != 512 && n != 1024 && n != 2048 && n != 4096)
                                return 0;
                        uopt->blocksize = n;
                        uopt->flags |= (1 << UDF_FLAG_BLOCKSIZE_SET);
                        break;
                case Opt_unhide:
                        uopt->flags |= (1 << UDF_FLAG_UNHIDE);
                        break;
                case Opt_undelete:
                        uopt->flags |= (1 << UDF_FLAG_UNDELETE);
                        break;
                case Opt_noadinicb:
                        uopt->flags &= ~(1 << UDF_FLAG_USE_AD_IN_ICB);
                        break;
                case Opt_adinicb:
                        uopt->flags |= (1 << UDF_FLAG_USE_AD_IN_ICB);
                        break;
                case Opt_shortad:
                        uopt->flags |= (1 << UDF_FLAG_USE_SHORT_AD);
                        break;
                case Opt_longad:
                        uopt->flags &= ~(1 << UDF_FLAG_USE_SHORT_AD);
                        break;
                case Opt_gid:
                        if (match_uint(args, &uv))
                                return 0;
                        uopt->gid = make_kgid(current_user_ns(), uv);
                        if (!gid_valid(uopt->gid))
                                return 0;
                        uopt->flags |= (1 << UDF_FLAG_GID_SET);
                        break;
                case Opt_uid:
                        if (match_uint(args, &uv))
                                return 0;
                        uopt->uid = make_kuid(current_user_ns(), uv);
                        if (!uid_valid(uopt->uid))
                                return 0;
                        uopt->flags |= (1 << UDF_FLAG_UID_SET);
                        break;
                case Opt_umask:
                        if (match_octal(args, &option))
                                return 0;
                        uopt->umask = option;
                        break;
                case Opt_nostrict:
                        uopt->flags &= ~(1 << UDF_FLAG_STRICT);
                        break;
                case Opt_session:
                        if (match_int(args, &option))
                                return 0;
                        uopt->session = option;
                        if (!remount)
                                uopt->flags |= (1 << UDF_FLAG_SESSION_SET);
                        break;
                case Opt_lastblock:
                        if (match_int(args, &option))
                                return 0;
                        uopt->lastblock = option;
                        if (!remount)
                                uopt->flags |= (1 << UDF_FLAG_LASTBLOCK_SET);
                        break;
                case Opt_anchor:
                        if (match_int(args, &option))
                                return 0;
                        uopt->anchor = option;
                        break;
                case Opt_volume:
                case Opt_partition:
                case Opt_fileset:
                case Opt_rootdir:
                        /* Ignored (never implemented properly) */
                        break;
                case Opt_utf8:
                        uopt->flags |= (1 << UDF_FLAG_UTF8);
                        break;
                case Opt_iocharset:
                        if (!remount) {
                                if (uopt->nls_map)
                                        unload_nls(uopt->nls_map);
                                /*
                                 * load_nls() failure is handled later in
                                 * udf_fill_super() after all options are
                                 * parsed.
                                 */
                                uopt->nls_map = load_nls(args[0].from);
                                uopt->flags |= (1 << UDF_FLAG_NLS_MAP);
                        }
                        break;
                case Opt_uforget:
                        uopt->flags |= (1 << UDF_FLAG_UID_FORGET);
                        break;
                case Opt_uignore:
                case Opt_gignore:
                        /* These options are superseeded by uid=<number> */
                        break;
                case Opt_gforget:
                        uopt->flags |= (1 << UDF_FLAG_GID_FORGET);
                        break;
                case Opt_fmode:
                        if (match_octal(args, &option))
                                return 0;
                        uopt->fmode = option & 0777;
                        break;
                case Opt_dmode:
                        if (match_octal(args, &option))
                                return 0;
                        uopt->dmode = option & 0777;
                        break;
                default:
                        pr_err("bad mount option \"%s\" or missing value\n", p);
                        return 0;
                }
        }
        return 1;
}

static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
{
        struct udf_options uopt;
        struct udf_sb_info *sbi = UDF_SB(sb);
        int error = 0;

        if (!(*flags & SB_RDONLY) && UDF_QUERY_FLAG(sb, UDF_FLAG_RW_INCOMPAT))
                return -EACCES;

        sync_filesystem(sb);

        uopt.flags = sbi->s_flags;
        uopt.uid   = sbi->s_uid;
        uopt.gid   = sbi->s_gid;
        uopt.umask = sbi->s_umask;
        uopt.fmode = sbi->s_fmode;
        uopt.dmode = sbi->s_dmode;
        uopt.nls_map = NULL;

        if (!udf_parse_options(options, &uopt, true))
                return -EINVAL;

        write_lock(&sbi->s_cred_lock);
        sbi->s_flags = uopt.flags;
        sbi->s_uid   = uopt.uid;
        sbi->s_gid   = uopt.gid;
        sbi->s_umask = uopt.umask;
        sbi->s_fmode = uopt.fmode;
        sbi->s_dmode = uopt.dmode;
        write_unlock(&sbi->s_cred_lock);

        if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
                goto out_unlock;

        if (*flags & SB_RDONLY)
                udf_close_lvid(sb);
        else
                udf_open_lvid(sb);

out_unlock:
        return error;
}

/*
 * Check VSD descriptor. Returns -1 in case we are at the end of volume
 * recognition area, 0 if the descriptor is valid but non-interesting, 1 if
 * we found one of NSR descriptors we are looking for.
 */
static int identify_vsd(const struct volStructDesc *vsd)
{
        int ret = 0;

        if (!memcmp(vsd->stdIdent, VSD_STD_ID_CD001, VSD_STD_ID_LEN)) {
                switch (vsd->structType) {
                case 0:
                        udf_debug("ISO9660 Boot Record found\n");
                        break;
                case 1:
                        udf_debug("ISO9660 Primary Volume Descriptor found\n");
                        break;
                case 2:
                        udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
                        break;
                case 3:
                        udf_debug("ISO9660 Volume Partition Descriptor found\n");
                        break;
                case 255:
                        udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
                        break;
                default:
                        udf_debug("ISO9660 VRS (%u) found\n", vsd->structType);
                        break;
                }
        } else if (!memcmp(vsd->stdIdent, VSD_STD_ID_BEA01, VSD_STD_ID_LEN))
                ; /* ret = 0 */
        else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR02, VSD_STD_ID_LEN))
                ret = 1;
        else if (!memcmp(vsd->stdIdent, VSD_STD_ID_NSR03, VSD_STD_ID_LEN))
                ret = 1;
        else if (!memcmp(vsd->stdIdent, VSD_STD_ID_BOOT2, VSD_STD_ID_LEN))
                ; /* ret = 0 */
        else if (!memcmp(vsd->stdIdent, VSD_STD_ID_CDW02, VSD_STD_ID_LEN))
                ; /* ret = 0 */
        else {
                /* TEA01 or invalid id : end of volume recognition area */
                ret = -1;
        }

        return ret;
}

/*
 * Check Volume Structure Descriptors (ECMA 167 2/9.1)
 * We also check any "CD-ROM Volume Descriptor Set" (ECMA 167 2/8.3.1)
 * @return   1 if NSR02 or NSR03 found,
 *          -1 if first sector read error, 0 otherwise
 */
static int udf_check_vsd(struct super_block *sb)
{
        struct volStructDesc *vsd = NULL;
        loff_t sector = VSD_FIRST_SECTOR_OFFSET;
        int sectorsize;
        struct buffer_head *bh = NULL;
        int nsr = 0;
        struct udf_sb_info *sbi;
        loff_t session_offset;

        sbi = UDF_SB(sb);
        if (sb->s_blocksize < sizeof(struct volStructDesc))
                sectorsize = sizeof(struct volStructDesc);
        else
                sectorsize = sb->s_blocksize;

        session_offset = (loff_t)sbi->s_session << sb->s_blocksize_bits;
        sector += session_offset;

        udf_debug("Starting at sector %u (%lu byte sectors)\n",
                  (unsigned int)(sector >> sb->s_blocksize_bits),
                  sb->s_blocksize);
        /* Process the sequence (if applicable). The hard limit on the sector
         * offset is arbitrary, hopefully large enough so that all valid UDF
         * filesystems will be recognised. There is no mention of an upper
         * bound to the size of the volume recognition area in the standard.
         *  The limit will prevent the code to read all the sectors of a
         * specially crafted image (like a bluray disc full of CD001 sectors),
         * potentially causing minutes or even hours of uninterruptible I/O
         * activity. This actually happened with uninitialised SSD partitions
         * (all 0xFF) before the check for the limit and all valid IDs were
         * added */
        for (; !nsr && sector < VSD_MAX_SECTOR_OFFSET; sector += sectorsize) {
                /* Read a block */
                bh = udf_tread(sb, sector >> sb->s_blocksize_bits);
                if (!bh)
                        break;

                vsd = (struct volStructDesc *)(bh->b_data +
                                              (sector & (sb->s_blocksize - 1)));
                nsr = identify_vsd(vsd);
                /* Found NSR or end? */
                if (nsr) {
                        brelse(bh);
                        break;
                }
                /*
                 * Special handling for improperly formatted VRS (e.g., Win10)
                 * where components are separated by 2048 bytes even though
                 * sectors are 4K
                 */
                if (sb->s_blocksize == 4096) {
                        nsr = identify_vsd(vsd + 1);
                        /* Ignore unknown IDs... */
                        if (nsr < 0)
                                nsr = 0;
                }
                brelse(bh);
        }

        if (nsr > 0)
                return 1;
        else if (!bh && sector - session_offset == VSD_FIRST_SECTOR_OFFSET)
                return -1;
        else
                return 0;
}

static int udf_verify_domain_identifier(struct super_block *sb,
                                        struct regid *ident, char *dname)
{
        struct domainIdentSuffix *suffix;

        if (memcmp(ident->ident, UDF_ID_COMPLIANT, strlen(UDF_ID_COMPLIANT))) {
                udf_warn(sb, "Not OSTA UDF compliant %s descriptor.\n", dname);
                goto force_ro;
        }
        if (ident->flags & ENTITYID_FLAGS_DIRTY) {
                udf_warn(sb, "Possibly not OSTA UDF compliant %s descriptor.\n",
                         dname);
                goto force_ro;
        }
        suffix = (struct domainIdentSuffix *)ident->identSuffix;
        if ((suffix->domainFlags & DOMAIN_FLAGS_HARD_WRITE_PROTECT) ||
            (suffix->domainFlags & DOMAIN_FLAGS_SOFT_WRITE_PROTECT)) {
                if (!sb_rdonly(sb)) {
                        udf_warn(sb, "Descriptor for %s marked write protected."
                                 " Forcing read only mount.\n", dname);
                }
                goto force_ro;
        }
        return 0;

force_ro:
        if (!sb_rdonly(sb))
                return -EACCES;
        UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
        return 0;
}

static int udf_load_fileset(struct super_block *sb, struct fileSetDesc *fset,
                            struct kernel_lb_addr *root)
{
        int ret;

        ret = udf_verify_domain_identifier(sb, &fset->domainIdent, "file set");
        if (ret < 0)
                return ret;

        *root = lelb_to_cpu(fset->rootDirectoryICB.extLocation);
        UDF_SB(sb)->s_serial_number = le16_to_cpu(fset->descTag.tagSerialNum);

        udf_debug("Rootdir at block=%u, partition=%u\n",
                  root->logicalBlockNum, root->partitionReferenceNum);
        return 0;
}

static int udf_find_fileset(struct super_block *sb,
                            struct kernel_lb_addr *fileset,
                            struct kernel_lb_addr *root)
{
        struct buffer_head *bh = NULL;
        uint16_t ident;
        int ret;

        if (fileset->logicalBlockNum == 0xFFFFFFFF &&
            fileset->partitionReferenceNum == 0xFFFF)
                return -EINVAL;

        bh = udf_read_ptagged(sb, fileset, 0, &ident);
        if (!bh)
                return -EIO;
        if (ident != TAG_IDENT_FSD) {
                brelse(bh);
                return -EINVAL;
        }

        udf_debug("Fileset at block=%u, partition=%u\n",
                  fileset->logicalBlockNum, fileset->partitionReferenceNum);

        UDF_SB(sb)->s_partition = fileset->partitionReferenceNum;
        ret = udf_load_fileset(sb, (struct fileSetDesc *)bh->b_data, root);
        brelse(bh);
        return ret;
}

/*
 * Load primary Volume Descriptor Sequence
 *
 * Return <0 on error, 0 on success. -EAGAIN is special meaning next sequence
 * should be tried.
 */
static int udf_load_pvoldesc(struct super_block *sb, sector_t block)
{
        struct primaryVolDesc *pvoldesc;
        uint8_t *outstr;
        struct buffer_head *bh;
        uint16_t ident;
        int ret;
        struct timestamp *ts;

        outstr = kmalloc(128, GFP_NOFS);
        if (!outstr)
                return -ENOMEM;

        bh = udf_read_tagged(sb, block, block, &ident);
        if (!bh) {
                ret = -EAGAIN;
                goto out2;
        }

        if (ident != TAG_IDENT_PVD) {
                ret = -EIO;
                goto out_bh;
        }

        pvoldesc = (struct primaryVolDesc *)bh->b_data;

        udf_disk_stamp_to_time(&UDF_SB(sb)->s_record_time,
                              pvoldesc->recordingDateAndTime);
        ts = &pvoldesc->recordingDateAndTime;
        udf_debug("recording time %04u/%02u/%02u %02u:%02u (%x)\n",
                  le16_to_cpu(ts->year), ts->month, ts->day, ts->hour,
                  ts->minute, le16_to_cpu(ts->typeAndTimezone));

        ret = udf_dstrCS0toChar(sb, outstr, 31, pvoldesc->volIdent, 32);
        if (ret < 0) {
                strcpy(UDF_SB(sb)->s_volume_ident, "InvalidName");
                pr_warn("incorrect volume identification, setting to "
                        "'InvalidName'\n");
        } else {
                strncpy(UDF_SB(sb)->s_volume_ident, outstr, ret);
        }
        udf_debug("volIdent[] = '%s'\n", UDF_SB(sb)->s_volume_ident);

        ret = udf_dstrCS0toChar(sb, outstr, 127, pvoldesc->volSetIdent, 128);
        if (ret < 0) {
                ret = 0;
                goto out_bh;
        }
        outstr[ret] = 0;
        udf_debug("volSetIdent[] = '%s'\n", outstr);

        ret = 0;
out_bh:
        brelse(bh);
out2:
        kfree(outstr);
        return ret;
}

struct inode *udf_find_metadata_inode_efe(struct super_block *sb,
                                        u32 meta_file_loc, u32 partition_ref)
{
        struct kernel_lb_addr addr;
        struct inode *metadata_fe;

        addr.logicalBlockNum = meta_file_loc;
        addr.partitionReferenceNum = partition_ref;

        metadata_fe = udf_iget_special(sb, &addr);

        if (IS_ERR(metadata_fe)) {
                udf_warn(sb, "metadata inode efe not found\n");
                return metadata_fe;
        }
        if (UDF_I(metadata_fe)->i_alloc_type != ICBTAG_FLAG_AD_SHORT) {
                udf_warn(sb, "metadata inode efe does not have short allocation descriptors!\n");
                iput(metadata_fe);
                return ERR_PTR(-EIO);
        }

        return metadata_fe;
}

static int udf_load_metadata_files(struct super_block *sb, int partition,
                                   int type1_index)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct udf_part_map *map;
        struct udf_meta_data *mdata;
        struct kernel_lb_addr addr;
        struct inode *fe;

        map = &sbi->s_partmaps[partition];
        mdata = &map->s_type_specific.s_metadata;
        mdata->s_phys_partition_ref = type1_index;

        /* metadata address */
        udf_debug("Metadata file location: block = %u part = %u\n",
                  mdata->s_meta_file_loc, mdata->s_phys_partition_ref);

        fe = udf_find_metadata_inode_efe(sb, mdata->s_meta_file_loc,
                                         mdata->s_phys_partition_ref);
        if (IS_ERR(fe)) {
                /* mirror file entry */
                udf_debug("Mirror metadata file location: block = %u part = %u\n",
                          mdata->s_mirror_file_loc, mdata->s_phys_partition_ref);

                fe = udf_find_metadata_inode_efe(sb, mdata->s_mirror_file_loc,
                                                 mdata->s_phys_partition_ref);

                if (IS_ERR(fe)) {
                        udf_err(sb, "Both metadata and mirror metadata inode efe can not found\n");
                        return PTR_ERR(fe);
                }
                mdata->s_mirror_fe = fe;
        } else
                mdata->s_metadata_fe = fe;


        /*
         * bitmap file entry
         * Note:
         * Load only if bitmap file location differs from 0xFFFFFFFF (DCN-5102)
        */
        if (mdata->s_bitmap_file_loc != 0xFFFFFFFF) {
                addr.logicalBlockNum = mdata->s_bitmap_file_loc;
                addr.partitionReferenceNum = mdata->s_phys_partition_ref;

                udf_debug("Bitmap file location: block = %u part = %u\n",
                          addr.logicalBlockNum, addr.partitionReferenceNum);

                fe = udf_iget_special(sb, &addr);
                if (IS_ERR(fe)) {
                        if (sb_rdonly(sb))
                                udf_warn(sb, "bitmap inode efe not found but it's ok since the disc is mounted read-only\n");
                        else {
                                udf_err(sb, "bitmap inode efe not found and attempted read-write mount\n");
                                return PTR_ERR(fe);
                        }
                } else
                        mdata->s_bitmap_fe = fe;
        }

        udf_debug("udf_load_metadata_files Ok\n");
        return 0;
}

int udf_compute_nr_groups(struct super_block *sb, u32 partition)

{
        struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
        return DIV_ROUND_UP(map->s_partition_len +
                            (sizeof(struct spaceBitmapDesc) << 3),
                            sb->s_blocksize * 8);
}

static struct udf_bitmap *udf_sb_alloc_bitmap(struct super_block *sb, u32 index)
{
        struct udf_bitmap *bitmap;
        int nr_groups = udf_compute_nr_groups(sb, index);

        bitmap = kvzalloc(struct_size(bitmap, s_block_bitmap, nr_groups),
                          GFP_KERNEL);
        if (!bitmap)
                return NULL;

        bitmap->s_nr_groups = nr_groups;
        return bitmap;
}

static int check_partition_desc(struct super_block *sb,
                                struct partitionDesc *p,
                                struct udf_part_map *map)
{
        bool umap, utable, fmap, ftable;
        struct partitionHeaderDesc *phd;

        switch (le32_to_cpu(p->accessType)) {
        case PD_ACCESS_TYPE_READ_ONLY:
        case PD_ACCESS_TYPE_WRITE_ONCE:
        case PD_ACCESS_TYPE_NONE:
                goto force_ro;
        }

        /* No Partition Header Descriptor? */
        if (strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR02) &&
            strcmp(p->partitionContents.ident, PD_PARTITION_CONTENTS_NSR03))
                goto force_ro;

        phd = (struct partitionHeaderDesc *)p->partitionContentsUse;
        utable = phd->unallocSpaceTable.extLength;
        umap = phd->unallocSpaceBitmap.extLength;
        ftable = phd->freedSpaceTable.extLength;
        fmap = phd->freedSpaceBitmap.extLength;

        /* No allocation info? */
        if (!utable && !umap && !ftable && !fmap)
                goto force_ro;

        /* We don't support blocks that require erasing before overwrite */
        if (ftable || fmap)
                goto force_ro;
        /* UDF 2.60: 2.3.3 - no mixing of tables & bitmaps, no VAT. */
        if (utable && umap)
                goto force_ro;

        if (map->s_partition_type == UDF_VIRTUAL_MAP15 ||
            map->s_partition_type == UDF_VIRTUAL_MAP20 ||
            map->s_partition_type == UDF_METADATA_MAP25)
                goto force_ro;

        return 0;
force_ro:
        if (!sb_rdonly(sb))
                return -EACCES;
        UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
        return 0;
}

static int udf_fill_partdesc_info(struct super_block *sb,
                struct partitionDesc *p, int p_index)
{
        struct udf_part_map *map;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct partitionHeaderDesc *phd;
        int err;

        map = &sbi->s_partmaps[p_index];

        map->s_partition_len = le32_to_cpu(p->partitionLength); /* blocks */
        map->s_partition_root = le32_to_cpu(p->partitionStartingLocation);

        if (p->accessType == cpu_to_le32(PD_ACCESS_TYPE_READ_ONLY))
                map->s_partition_flags |= UDF_PART_FLAG_READ_ONLY;
        if (p->accessType == cpu_to_le32(PD_ACCESS_TYPE_WRITE_ONCE))
                map->s_partition_flags |= UDF_PART_FLAG_WRITE_ONCE;
        if (p->accessType == cpu_to_le32(PD_ACCESS_TYPE_REWRITABLE))
                map->s_partition_flags |= UDF_PART_FLAG_REWRITABLE;
        if (p->accessType == cpu_to_le32(PD_ACCESS_TYPE_OVERWRITABLE))
                map->s_partition_flags |= UDF_PART_FLAG_OVERWRITABLE;

        udf_debug("Partition (%d type %x) starts at physical %u, block length %u\n",
                  p_index, map->s_partition_type,
                  map->s_partition_root, map->s_partition_len);

        err = check_partition_desc(sb, p, map);
        if (err)
                return err;

        /*
         * Skip loading allocation info it we cannot ever write to the fs.
         * This is a correctness thing as we may have decided to force ro mount
         * to avoid allocation info we don't support.
         */
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_RW_INCOMPAT))
                return 0;

        phd = (struct partitionHeaderDesc *)p->partitionContentsUse;
        if (phd->unallocSpaceTable.extLength) {
                struct kernel_lb_addr loc = {
                        .logicalBlockNum = le32_to_cpu(
                                phd->unallocSpaceTable.extPosition),
                        .partitionReferenceNum = p_index,
                };
                struct inode *inode;

                inode = udf_iget_special(sb, &loc);
                if (IS_ERR(inode)) {
                        udf_debug("cannot load unallocSpaceTable (part %d)\n",
                                  p_index);
                        return PTR_ERR(inode);
                }
                map->s_uspace.s_table = inode;
                map->s_partition_flags |= UDF_PART_FLAG_UNALLOC_TABLE;
                udf_debug("unallocSpaceTable (part %d) @ %lu\n",
                          p_index, map->s_uspace.s_table->i_ino);
        }

        if (phd->unallocSpaceBitmap.extLength) {
                struct udf_bitmap *bitmap = udf_sb_alloc_bitmap(sb, p_index);
                if (!bitmap)
                        return -ENOMEM;
                map->s_uspace.s_bitmap = bitmap;
                bitmap->s_extPosition = le32_to_cpu(
                                phd->unallocSpaceBitmap.extPosition);
                map->s_partition_flags |= UDF_PART_FLAG_UNALLOC_BITMAP;
                udf_debug("unallocSpaceBitmap (part %d) @ %u\n",
                          p_index, bitmap->s_extPosition);
        }

        return 0;
}

static void udf_find_vat_block(struct super_block *sb, int p_index,
                               int type1_index, sector_t start_block)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct udf_part_map *map = &sbi->s_partmaps[p_index];
        sector_t vat_block;
        struct kernel_lb_addr ino;
        struct inode *inode;

        /*
         * VAT file entry is in the last recorded block. Some broken disks have
         * it a few blocks before so try a bit harder...
         */
        ino.partitionReferenceNum = type1_index;
        for (vat_block = start_block;
             vat_block >= map->s_partition_root &&
             vat_block >= start_block - 3; vat_block--) {
                ino.logicalBlockNum = vat_block - map->s_partition_root;
                inode = udf_iget_special(sb, &ino);
                if (!IS_ERR(inode)) {
                        sbi->s_vat_inode = inode;
                        break;
                }
        }
}

static int udf_load_vat(struct super_block *sb, int p_index, int type1_index)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct udf_part_map *map = &sbi->s_partmaps[p_index];
        struct buffer_head *bh = NULL;
        struct udf_inode_info *vati;
        uint32_t pos;
        struct virtualAllocationTable20 *vat20;
        sector_t blocks = i_size_read(sb->s_bdev->bd_inode) >>
                          sb->s_blocksize_bits;

        udf_find_vat_block(sb, p_index, type1_index, sbi->s_last_block);
        if (!sbi->s_vat_inode &&
            sbi->s_last_block != blocks - 1) {
                pr_notice("Failed to read VAT inode from the last recorded block (%lu), retrying with the last block of the device (%lu).\n",
                          (unsigned long)sbi->s_last_block,
                          (unsigned long)blocks - 1);
                udf_find_vat_block(sb, p_index, type1_index, blocks - 1);
        }
        if (!sbi->s_vat_inode)
                return -EIO;

        if (map->s_partition_type == UDF_VIRTUAL_MAP15) {
                map->s_type_specific.s_virtual.s_start_offset = 0;
                map->s_type_specific.s_virtual.s_num_entries =
                        (sbi->s_vat_inode->i_size - 36) >> 2;
        } else if (map->s_partition_type == UDF_VIRTUAL_MAP20) {
                vati = UDF_I(sbi->s_vat_inode);
                if (vati->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
                        pos = udf_block_map(sbi->s_vat_inode, 0);
                        bh = sb_bread(sb, pos);
                        if (!bh)
                                return -EIO;
                        vat20 = (struct virtualAllocationTable20 *)bh->b_data;
                } else {
                        vat20 = (struct virtualAllocationTable20 *)
                                                        vati->i_data;
                }

                map->s_type_specific.s_virtual.s_start_offset =
                        le16_to_cpu(vat20->lengthHeader);
                map->s_type_specific.s_virtual.s_num_entries =
                        (sbi->s_vat_inode->i_size -
                                map->s_type_specific.s_virtual.
                                        s_start_offset) >> 2;
                brelse(bh);
        }
        return 0;
}

/*
 * Load partition descriptor block
 *
 * Returns <0 on error, 0 on success, -EAGAIN is special - try next descriptor
 * sequence.
 */
static int udf_load_partdesc(struct super_block *sb, sector_t block)
{
        struct buffer_head *bh;
        struct partitionDesc *p;
        struct udf_part_map *map;
        struct udf_sb_info *sbi = UDF_SB(sb);
        int i, type1_idx;
        uint16_t partitionNumber;
        uint16_t ident;
        int ret;

        bh = udf_read_tagged(sb, block, block, &ident);
        if (!bh)
                return -EAGAIN;
        if (ident != TAG_IDENT_PD) {
                ret = 0;
                goto out_bh;
        }

        p = (struct partitionDesc *)bh->b_data;
        partitionNumber = le16_to_cpu(p->partitionNumber);

        /* First scan for TYPE1 and SPARABLE partitions */
        for (i = 0; i < sbi->s_partitions; i++) {
                map = &sbi->s_partmaps[i];
                udf_debug("Searching map: (%u == %u)\n",
                          map->s_partition_num, partitionNumber);
                if (map->s_partition_num == partitionNumber &&
                    (map->s_partition_type == UDF_TYPE1_MAP15 ||
                     map->s_partition_type == UDF_SPARABLE_MAP15))
                        break;
        }

        if (i >= sbi->s_partitions) {
                udf_debug("Partition (%u) not found in partition map\n",
                          partitionNumber);
                ret = 0;
                goto out_bh;
        }

        ret = udf_fill_partdesc_info(sb, p, i);
        if (ret < 0)
                goto out_bh;

        /*
         * Now rescan for VIRTUAL or METADATA partitions when SPARABLE and
         * PHYSICAL partitions are already set up
         */
        type1_idx = i;
        map = NULL; /* supress 'maybe used uninitialized' warning */
        for (i = 0; i < sbi->s_partitions; i++) {
                map = &sbi->s_partmaps[i];

                if (map->s_partition_num == partitionNumber &&
                    (map->s_partition_type == UDF_VIRTUAL_MAP15 ||
                     map->s_partition_type == UDF_VIRTUAL_MAP20 ||
                     map->s_partition_type == UDF_METADATA_MAP25))
                        break;
        }

        if (i >= sbi->s_partitions) {
                ret = 0;
                goto out_bh;
        }

        ret = udf_fill_partdesc_info(sb, p, i);
        if (ret < 0)
                goto out_bh;

        if (map->s_partition_type == UDF_METADATA_MAP25) {
                ret = udf_load_metadata_files(sb, i, type1_idx);
                if (ret < 0) {
                        udf_err(sb, "error loading MetaData partition map %d\n",
                                i);
                        goto out_bh;
                }
        } else {
                /*
                 * If we have a partition with virtual map, we don't handle
                 * writing to it (we overwrite blocks instead of relocating
                 * them).
                 */
                if (!sb_rdonly(sb)) {
                        ret = -EACCES;
                        goto out_bh;
                }
                UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
                ret = udf_load_vat(sb, i, type1_idx);
                if (ret < 0)
                        goto out_bh;
        }
        ret = 0;
out_bh:
        /* In case loading failed, we handle cleanup in udf_fill_super */
        brelse(bh);
        return ret;
}

static int udf_load_sparable_map(struct super_block *sb,
                                 struct udf_part_map *map,
                                 struct sparablePartitionMap *spm)
{
        uint32_t loc;
        uint16_t ident;
        struct sparingTable *st;
        struct udf_sparing_data *sdata = &map->s_type_specific.s_sparing;
        int i;
        struct buffer_head *bh;

        map->s_partition_type = UDF_SPARABLE_MAP15;
        sdata->s_packet_len = le16_to_cpu(spm->packetLength);
        if (!is_power_of_2(sdata->s_packet_len)) {
                udf_err(sb, "error loading logical volume descriptor: "
                        "Invalid packet length %u\n",
                        (unsigned)sdata->s_packet_len);
                return -EIO;
        }
        if (spm->numSparingTables > 4) {
                udf_err(sb, "error loading logical volume descriptor: "
                        "Too many sparing tables (%d)\n",
                        (int)spm->numSparingTables);
                return -EIO;
        }
        if (le32_to_cpu(spm->sizeSparingTable) > sb->s_blocksize) {
                udf_err(sb, "error loading logical volume descriptor: "
                        "Too big sparing table size (%u)\n",
                        le32_to_cpu(spm->sizeSparingTable));
                return -EIO;
        }

        for (i = 0; i < spm->numSparingTables; i++) {
                loc = le32_to_cpu(spm->locSparingTable[i]);
                bh = udf_read_tagged(sb, loc, loc, &ident);
                if (!bh)
                        continue;

                st = (struct sparingTable *)bh->b_data;
                if (ident != 0 ||
                    strncmp(st->sparingIdent.ident, UDF_ID_SPARING,
                            strlen(UDF_ID_SPARING)) ||
                    sizeof(*st) + le16_to_cpu(st->reallocationTableLen) >
                                                        sb->s_blocksize) {
                        brelse(bh);
                        continue;
                }

                sdata->s_spar_map[i] = bh;
        }
        map->s_partition_func = udf_get_pblock_spar15;
        return 0;
}

static int udf_load_logicalvol(struct super_block *sb, sector_t block,
                               struct kernel_lb_addr *fileset)
{
        struct logicalVolDesc *lvd;
        int i, offset;
        uint8_t type;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct genericPartitionMap *gpm;
        uint16_t ident;
        struct buffer_head *bh;
        unsigned int table_len;
        int ret;

        bh = udf_read_tagged(sb, block, block, &ident);
        if (!bh)
                return -EAGAIN;
        BUG_ON(ident != TAG_IDENT_LVD);
        lvd = (struct logicalVolDesc *)bh->b_data;
        table_len = le32_to_cpu(lvd->mapTableLength);
        if (table_len > sb->s_blocksize - sizeof(*lvd)) {
                udf_err(sb, "error loading logical volume descriptor: "
                        "Partition table too long (%u > %lu)\n", table_len,
                        sb->s_blocksize - sizeof(*lvd));
                ret = -EIO;
                goto out_bh;
        }

        ret = udf_verify_domain_identifier(sb, &lvd->domainIdent,
                                           "logical volume");
        if (ret)
                goto out_bh;
        ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
        if (ret)
                goto out_bh;

        for (i = 0, offset = 0;
             i < sbi->s_partitions && offset < table_len;
             i++, offset += gpm->partitionMapLength) {
                struct udf_part_map *map = &sbi->s_partmaps[i];
                gpm = (struct genericPartitionMap *)
                                &(lvd->partitionMaps[offset]);
                type = gpm->partitionMapType;
                if (type == 1) {
                        struct genericPartitionMap1 *gpm1 =
                                (struct genericPartitionMap1 *)gpm;
                        map->s_partition_type = UDF_TYPE1_MAP15;
                        map->s_volumeseqnum = le16_to_cpu(gpm1->volSeqNum);
                        map->s_partition_num = le16_to_cpu(gpm1->partitionNum);
                        map->s_partition_func = NULL;
                } else if (type == 2) {
                        struct udfPartitionMap2 *upm2 =
                                                (struct udfPartitionMap2 *)gpm;
                        if (!strncmp(upm2->partIdent.ident, UDF_ID_VIRTUAL,
                                                strlen(UDF_ID_VIRTUAL))) {
                                u16 suf =
                                        le16_to_cpu(((__le16 *)upm2->partIdent.
                                                        identSuffix)[0]);
                                if (suf < 0x0200) {
                                        map->s_partition_type =
                                                        UDF_VIRTUAL_MAP15;
                                        map->s_partition_func =
                                                        udf_get_pblock_virt15;
                                } else {
                                        map->s_partition_type =
                                                        UDF_VIRTUAL_MAP20;
                                        map->s_partition_func =
                                                        udf_get_pblock_virt20;
                                }
                        } else if (!strncmp(upm2->partIdent.ident,
                                                UDF_ID_SPARABLE,
                                                strlen(UDF_ID_SPARABLE))) {
                                ret = udf_load_sparable_map(sb, map,
                                        (struct sparablePartitionMap *)gpm);
                                if (ret < 0)
                                        goto out_bh;
                        } else if (!strncmp(upm2->partIdent.ident,
                                                UDF_ID_METADATA,
                                                strlen(UDF_ID_METADATA))) {
                                struct udf_meta_data *mdata =
                                        &map->s_type_specific.s_metadata;
                                struct metadataPartitionMap *mdm =
                                                (struct metadataPartitionMap *)
                                                &(lvd->partitionMaps[offset]);
                                udf_debug("Parsing Logical vol part %d type %u  id=%s\n",
                                          i, type, UDF_ID_METADATA);

                                map->s_partition_type = UDF_METADATA_MAP25;
                                map->s_partition_func = udf_get_pblock_meta25;

                                mdata->s_meta_file_loc   =
                                        le32_to_cpu(mdm->metadataFileLoc);
                                mdata->s_mirror_file_loc =
                                        le32_to_cpu(mdm->metadataMirrorFileLoc);
                                mdata->s_bitmap_file_loc =
                                        le32_to_cpu(mdm->metadataBitmapFileLoc);
                                mdata->s_alloc_unit_size =
                                        le32_to_cpu(mdm->allocUnitSize);
                                mdata->s_align_unit_size =
                                        le16_to_cpu(mdm->alignUnitSize);
                                if (mdm->flags & 0x01)
                                        mdata->s_flags |= MF_DUPLICATE_MD;

                                udf_debug("Metadata Ident suffix=0x%x\n",
                                          le16_to_cpu(*(__le16 *)
                                                      mdm->partIdent.identSuffix));
                                udf_debug("Metadata part num=%u\n",
                                          le16_to_cpu(mdm->partitionNum));
                                udf_debug("Metadata part alloc unit size=%u\n",
                                          le32_to_cpu(mdm->allocUnitSize));
                                udf_debug("Metadata file loc=%u\n",
                                          le32_to_cpu(mdm->metadataFileLoc));
                                udf_debug("Mirror file loc=%u\n",
                                          le32_to_cpu(mdm->metadataMirrorFileLoc));
                                udf_debug("Bitmap file loc=%u\n",
                                          le32_to_cpu(mdm->metadataBitmapFileLoc));
                                udf_debug("Flags: %d %u\n",
                                          mdata->s_flags, mdm->flags);
                        } else {
                                udf_debug("Unknown ident: %s\n",
                                          upm2->partIdent.ident);
                                continue;
                        }
                        map->s_volumeseqnum = le16_to_cpu(upm2->volSeqNum);
                        map->s_partition_num = le16_to_cpu(upm2->partitionNum);
                }
                udf_debug("Partition (%d:%u) type %u on volume %u\n",
                          i, map->s_partition_num, type, map->s_volumeseqnum);
        }

        if (fileset) {
                struct long_ad *la = (struct long_ad *)&(lvd->logicalVolContentsUse[0]);

                *fileset = lelb_to_cpu(la->extLocation);
                udf_debug("FileSet found in LogicalVolDesc at block=%u, partition=%u\n",
                          fileset->logicalBlockNum,
                          fileset->partitionReferenceNum);
        }
        if (lvd->integritySeqExt.extLength)
                udf_load_logicalvolint(sb, leea_to_cpu(lvd->integritySeqExt));
        ret = 0;

        if (!sbi->s_lvid_bh) {
                /* We can't generate unique IDs without a valid LVID */
                if (sb_rdonly(sb)) {
                        UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
                } else {
                        udf_warn(sb, "Damaged or missing LVID, forcing "
                                     "readonly mount\n");
                        ret = -EACCES;
                }
        }
out_bh:
        brelse(bh);
        return ret;
}

/*
 * Find the prevailing Logical Volume Integrity Descriptor.
 */
static void udf_load_logicalvolint(struct super_block *sb, struct kernel_extent_ad loc)
{
        struct buffer_head *bh, *final_bh;
        uint16_t ident;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct logicalVolIntegrityDesc *lvid;
        int indirections = 0;

        while (++indirections <= UDF_MAX_LVID_NESTING) {
                final_bh = NULL;
                while (loc.extLength > 0 &&
                        (bh = udf_read_tagged(sb, loc.extLocation,
                                        loc.extLocation, &ident))) {
                        if (ident != TAG_IDENT_LVID) {
                                brelse(bh);
                                break;
                        }

                        brelse(final_bh);
                        final_bh = bh;

                        loc.extLength -= sb->s_blocksize;
                        loc.extLocation++;
                }

                if (!final_bh)
                        return;

                brelse(sbi->s_lvid_bh);
                sbi->s_lvid_bh = final_bh;

                lvid = (struct logicalVolIntegrityDesc *)final_bh->b_data;
                if (lvid->nextIntegrityExt.extLength == 0)
                        return;

                loc = leea_to_cpu(lvid->nextIntegrityExt);
        }

        udf_warn(sb, "Too many LVID indirections (max %u), ignoring.\n",
                UDF_MAX_LVID_NESTING);
        brelse(sbi->s_lvid_bh);
        sbi->s_lvid_bh = NULL;
}

/*
 * Step for reallocation of table of partition descriptor sequence numbers.
 * Must be power of 2.
 */
#define PART_DESC_ALLOC_STEP 32

struct part_desc_seq_scan_data {
        struct udf_vds_record rec;
        u32 partnum;
};

struct desc_seq_scan_data {
        struct udf_vds_record vds[VDS_POS_LENGTH];
        unsigned int size_part_descs;
        unsigned int num_part_descs;
        struct part_desc_seq_scan_data *part_descs_loc;
};

static struct udf_vds_record *handle_partition_descriptor(
                                struct buffer_head *bh,
                                struct desc_seq_scan_data *data)
{
        struct partitionDesc *desc = (struct partitionDesc *)bh->b_data;
        int partnum;
        int i;

        partnum = le16_to_cpu(desc->partitionNumber);
        for (i = 0; i < data->num_part_descs; i++)
                if (partnum == data->part_descs_loc[i].partnum)
                        return &(data->part_descs_loc[i].rec);
        if (data->num_part_descs >= data->size_part_descs) {
                struct part_desc_seq_scan_data *new_loc;
                unsigned int new_size = ALIGN(partnum, PART_DESC_ALLOC_STEP);

                new_loc = kcalloc(new_size, sizeof(*new_loc), GFP_KERNEL);
                if (!new_loc)
                        return ERR_PTR(-ENOMEM);
                memcpy(new_loc, data->part_descs_loc,
                       data->size_part_descs * sizeof(*new_loc));
                kfree(data->part_descs_loc);
                data->part_descs_loc = new_loc;
                data->size_part_descs = new_size;
        }
        return &(data->part_descs_loc[data->num_part_descs++].rec);
}


static struct udf_vds_record *get_volume_descriptor_record(uint16_t ident,
                struct buffer_head *bh, struct desc_seq_scan_data *data)
{
        switch (ident) {
        case TAG_IDENT_PVD: /* ISO 13346 3/10.1 */
                return &(data->vds[VDS_POS_PRIMARY_VOL_DESC]);
        case TAG_IDENT_IUVD: /* ISO 13346 3/10.4 */
                return &(data->vds[VDS_POS_IMP_USE_VOL_DESC]);
        case TAG_IDENT_LVD: /* ISO 13346 3/10.6 */
                return &(data->vds[VDS_POS_LOGICAL_VOL_DESC]);
        case TAG_IDENT_USD: /* ISO 13346 3/10.8 */
                return &(data->vds[VDS_POS_UNALLOC_SPACE_DESC]);
        case TAG_IDENT_PD: /* ISO 13346 3/10.5 */
                return handle_partition_descriptor(bh, data);
        }
        return NULL;
}

/*
 * Process a main/reserve volume descriptor sequence.
 *   @block             First block of first extent of the sequence.
 *   @lastblock         Lastblock of first extent of the sequence.
 *   @fileset           There we store extent containing root fileset
 *
 * Returns <0 on error, 0 on success. -EAGAIN is special - try next descriptor
 * sequence
 */
static noinline int udf_process_sequence(
                struct super_block *sb,
                sector_t block, sector_t lastblock,
                struct kernel_lb_addr *fileset)
{
        struct buffer_head *bh = NULL;
        struct udf_vds_record *curr;
        struct generic_desc *gd;
        struct volDescPtr *vdp;
        bool done = false;
        uint32_t vdsn;
        uint16_t ident;
        int ret;
        unsigned int indirections = 0;
        struct desc_seq_scan_data data;
        unsigned int i;

        memset(data.vds, 0, sizeof(struct udf_vds_record) * VDS_POS_LENGTH);
        data.size_part_descs = PART_DESC_ALLOC_STEP;
        data.num_part_descs = 0;
        data.part_descs_loc = kcalloc(data.size_part_descs,
                                      sizeof(*data.part_descs_loc),
                                      GFP_KERNEL);
        if (!data.part_descs_loc)
                return -ENOMEM;

        /*
         * Read the main descriptor sequence and find which descriptors
         * are in it.
         */
        for (; (!done && block <= lastblock); block++) {
                bh = udf_read_tagged(sb, block, block, &ident);
                if (!bh)
                        break;

                /* Process each descriptor (ISO 13346 3/8.3-8.4) */
                gd = (struct generic_desc *)bh->b_data;
                vdsn = le32_to_cpu(gd->volDescSeqNum);
                switch (ident) {
                case TAG_IDENT_VDP: /* ISO 13346 3/10.3 */
                        if (++indirections > UDF_MAX_TD_NESTING) {
                                udf_err(sb, "too many Volume Descriptor "
                                        "Pointers (max %u supported)\n",
                                        UDF_MAX_TD_NESTING);
                                brelse(bh);
                                ret = -EIO;
                                goto out;
                        }

                        vdp = (struct volDescPtr *)bh->b_data;
                        block = le32_to_cpu(vdp->nextVolDescSeqExt.extLocation);
                        lastblock = le32_to_cpu(
                                vdp->nextVolDescSeqExt.extLength) >>
                                sb->s_blocksize_bits;
                        lastblock += block - 1;
                        /* For loop is going to increment 'block' again */
                        block--;
                        break;
                case TAG_IDENT_PVD: /* ISO 13346 3/10.1 */
                case TAG_IDENT_IUVD: /* ISO 13346 3/10.4 */
                case TAG_IDENT_LVD: /* ISO 13346 3/10.6 */
                case TAG_IDENT_USD: /* ISO 13346 3/10.8 */
                case TAG_IDENT_PD: /* ISO 13346 3/10.5 */
                        curr = get_volume_descriptor_record(ident, bh, &data);
                        if (IS_ERR(curr)) {
                                brelse(bh);
                                ret = PTR_ERR(curr);
                                goto out;
                        }
                        /* Descriptor we don't care about? */
                        if (!curr)
                                break;
                        if (vdsn >= curr->volDescSeqNum) {
                                curr->volDescSeqNum = vdsn;
                                curr->block = block;
                        }
                        break;
                case TAG_IDENT_TD: /* ISO 13346 3/10.9 */
                        done = true;
                        break;
                }
                brelse(bh);
        }
        /*
         * Now read interesting descriptors again and process them
         * in a suitable order
         */
        if (!data.vds[VDS_POS_PRIMARY_VOL_DESC].block) {
                udf_err(sb, "Primary Volume Descriptor not found!\n");
                ret = -EAGAIN;
                goto out;
        }
        ret = udf_load_pvoldesc(sb, data.vds[VDS_POS_PRIMARY_VOL_DESC].block);
        if (ret < 0)
                goto out;

        if (data.vds[VDS_POS_LOGICAL_VOL_DESC].block) {
                ret = udf_load_logicalvol(sb,
                                data.vds[VDS_POS_LOGICAL_VOL_DESC].block,
                                fileset);
                if (ret < 0)
                        goto out;
        }

        /* Now handle prevailing Partition Descriptors */
        for (i = 0; i < data.num_part_descs; i++) {
                ret = udf_load_partdesc(sb, data.part_descs_loc[i].rec.block);
                if (ret < 0)
                        goto out;
        }
        ret = 0;
out:
        kfree(data.part_descs_loc);
        return ret;
}

/*
 * Load Volume Descriptor Sequence described by anchor in bh
 *
 * Returns <0 on error, 0 on success
 */
static int udf_load_sequence(struct super_block *sb, struct buffer_head *bh,
                             struct kernel_lb_addr *fileset)
{
        struct anchorVolDescPtr *anchor;
        sector_t main_s, main_e, reserve_s, reserve_e;
        int ret;

        anchor = (struct anchorVolDescPtr *)bh->b_data;

        /* Locate the main sequence */
        main_s = le32_to_cpu(anchor->mainVolDescSeqExt.extLocation);
        main_e = le32_to_cpu(anchor->mainVolDescSeqExt.extLength);
        main_e = main_e >> sb->s_blocksize_bits;
        main_e += main_s - 1;

        /* Locate the reserve sequence */
        reserve_s = le32_to_cpu(anchor->reserveVolDescSeqExt.extLocation);
        reserve_e = le32_to_cpu(anchor->reserveVolDescSeqExt.extLength);
        reserve_e = reserve_e >> sb->s_blocksize_bits;
        reserve_e += reserve_s - 1;

        /* Process the main & reserve sequences */
        /* responsible for finding the PartitionDesc(s) */
        ret = udf_process_sequence(sb, main_s, main_e, fileset);
        if (ret != -EAGAIN)
                return ret;
        udf_sb_free_partitions(sb);
        ret = udf_process_sequence(sb, reserve_s, reserve_e, fileset);
        if (ret < 0) {
                udf_sb_free_partitions(sb);
                /* No sequence was OK, return -EIO */
                if (ret == -EAGAIN)
                        ret = -EIO;
        }
        return ret;
}

/*
 * Check whether there is an anchor block in the given block and
 * load Volume Descriptor Sequence if so.
 *
 * Returns <0 on error, 0 on success, -EAGAIN is special - try next anchor
 * block
 */
static int udf_check_anchor_block(struct super_block *sb, sector_t block,
                                  struct kernel_lb_addr *fileset)
{
        struct buffer_head *bh;
        uint16_t ident;
        int ret;

        if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV) &&
            udf_fixed_to_variable(block) >=
            i_size_read(sb->s_bdev->bd_inode) >> sb->s_blocksize_bits)
                return -EAGAIN;

        bh = udf_read_tagged(sb, block, block, &ident);
        if (!bh)
                return -EAGAIN;
        if (ident != TAG_IDENT_AVDP) {
                brelse(bh);
                return -EAGAIN;
        }
        ret = udf_load_sequence(sb, bh, fileset);
        brelse(bh);
        return ret;
}

/*
 * Search for an anchor volume descriptor pointer.
 *
 * Returns < 0 on error, 0 on success. -EAGAIN is special - try next set
 * of anchors.
 */
static int udf_scan_anchors(struct super_block *sb, sector_t *lastblock,
                            struct kernel_lb_addr *fileset)
{
        sector_t last[6];
        int i;
        struct udf_sb_info *sbi = UDF_SB(sb);
        int last_count = 0;
        int ret;

        /* First try user provided anchor */
        if (sbi->s_anchor) {
                ret = udf_check_anchor_block(sb, sbi->s_anchor, fileset);
                if (ret != -EAGAIN)
                        return ret;
        }
        /*
         * according to spec, anchor is in either:
         *     block 256
         *     lastblock-256
         *     lastblock
         *  however, if the disc isn't closed, it could be 512.
         */
        ret = udf_check_anchor_block(sb, sbi->s_session + 256, fileset);
        if (ret != -EAGAIN)
                return ret;
        /*
         * The trouble is which block is the last one. Drives often misreport
         * this so we try various possibilities.
         */
        last[last_count++] = *lastblock;
        if (*lastblock >= 1)
                last[last_count++] = *lastblock - 1;
        last[last_count++] = *lastblock + 1;
        if (*lastblock >= 2)
                last[last_count++] = *lastblock - 2;
        if (*lastblock >= 150)
                last[last_count++] = *lastblock - 150;
        if (*lastblock >= 152)
                last[last_count++] = *lastblock - 152;

        for (i = 0; i < last_count; i++) {
                if (last[i] >= i_size_read(sb->s_bdev->bd_inode) >>
                                sb->s_blocksize_bits)
                        continue;
                ret = udf_check_anchor_block(sb, last[i], fileset);
                if (ret != -EAGAIN) {
                        if (!ret)
                                *lastblock = last[i];
                        return ret;
                }
                if (last[i] < 256)
                        continue;
                ret = udf_check_anchor_block(sb, last[i] - 256, fileset);
                if (ret != -EAGAIN) {
                        if (!ret)
                                *lastblock = last[i];
                        return ret;
                }
        }

        /* Finally try block 512 in case media is open */
        return udf_check_anchor_block(sb, sbi->s_session + 512, fileset);
}

/*
 * Find an anchor volume descriptor and load Volume Descriptor Sequence from
 * area specified by it. The function expects sbi->s_lastblock to be the last
 * block on the media.
 *
 * Return <0 on error, 0 if anchor found. -EAGAIN is special meaning anchor
 * was not found.
 */
static int udf_find_anchor(struct super_block *sb,
                           struct kernel_lb_addr *fileset)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        sector_t lastblock = sbi->s_last_block;
        int ret;

        ret = udf_scan_anchors(sb, &lastblock, fileset);
        if (ret != -EAGAIN)
                goto out;

        /* No anchor found? Try VARCONV conversion of block numbers */
        UDF_SET_FLAG(sb, UDF_FLAG_VARCONV);
        lastblock = udf_variable_to_fixed(sbi->s_last_block);
        /* Firstly, we try to not convert number of the last block */
        ret = udf_scan_anchors(sb, &lastblock, fileset);
        if (ret != -EAGAIN)
                goto out;

        lastblock = sbi->s_last_block;
        /* Secondly, we try with converted number of the last block */
        ret = udf_scan_anchors(sb, &lastblock, fileset);
        if (ret < 0) {
                /* VARCONV didn't help. Clear it. */
                UDF_CLEAR_FLAG(sb, UDF_FLAG_VARCONV);
        }
out:
        if (ret == 0)
                sbi->s_last_block = lastblock;
        return ret;
}

/*
 * Check Volume Structure Descriptor, find Anchor block and load Volume
 * Descriptor Sequence.
 *
 * Returns < 0 on error, 0 on success. -EAGAIN is special meaning anchor
 * block was not found.
 */
static int udf_load_vrs(struct super_block *sb, struct udf_options *uopt,
                        int silent, struct kernel_lb_addr *fileset)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        int nsr = 0;
        int ret;

        if (!sb_set_blocksize(sb, uopt->blocksize)) {
                if (!silent)
                        udf_warn(sb, "Bad block size\n");
                return -EINVAL;
        }
        sbi->s_last_block = uopt->lastblock;
        if (!uopt->novrs) {
                /* Check that it is NSR02 compliant */
                nsr = udf_check_vsd(sb);
                if (!nsr) {
                        if (!silent)
                                udf_warn(sb, "No VRS found\n");
                        return -EINVAL;
                }
                if (nsr == -1)
                        udf_debug("Failed to read sector at offset %d. "
                                  "Assuming open disc. Skipping validity "
                                  "check\n", VSD_FIRST_SECTOR_OFFSET);
                if (!sbi->s_last_block)
                        sbi->s_last_block = udf_get_last_block(sb);
        } else {
                udf_debug("Validity check skipped because of novrs option\n");
        }

        /* Look for anchor block and load Volume Descriptor Sequence */
        sbi->s_anchor = uopt->anchor;
        ret = udf_find_anchor(sb, fileset);
        if (ret < 0) {
                if (!silent && ret == -EAGAIN)
                        udf_warn(sb, "No anchor found\n");
                return ret;
        }

        return 0;
}

static void udf_finalize_lvid(struct logicalVolIntegrityDesc *lvid)
{
        struct timespec64 ts;

        ktime_get_real_ts64(&ts);
        udf_time_to_disk_stamp(&lvid->recordingDateAndTime, ts);
        lvid->descTag.descCRC = cpu_to_le16(
                crc_itu_t(0, (char *)lvid + sizeof(struct tag),
                        le16_to_cpu(lvid->descTag.descCRCLength)));
        lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
}

static void udf_open_lvid(struct super_block *sb)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct buffer_head *bh = sbi->s_lvid_bh;
        struct logicalVolIntegrityDesc *lvid;
        struct logicalVolIntegrityDescImpUse *lvidiu;

        if (!bh)
                return;
        lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
        lvidiu = udf_sb_lvidiu(sb);
        if (!lvidiu)
                return;

        mutex_lock(&sbi->s_alloc_mutex);
        lvidiu->impIdent.identSuffix[0] = UDF_OS_CLASS_UNIX;
        lvidiu->impIdent.identSuffix[1] = UDF_OS_ID_LINUX;
        if (le32_to_cpu(lvid->integrityType) == LVID_INTEGRITY_TYPE_CLOSE)
                lvid->integrityType = cpu_to_le32(LVID_INTEGRITY_TYPE_OPEN);
        else
                UDF_SET_FLAG(sb, UDF_FLAG_INCONSISTENT);

        udf_finalize_lvid(lvid);
        mark_buffer_dirty(bh);
        sbi->s_lvid_dirty = 0;
        mutex_unlock(&sbi->s_alloc_mutex);
        /* Make opening of filesystem visible on the media immediately */
        sync_dirty_buffer(bh);
}

static void udf_close_lvid(struct super_block *sb)
{
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct buffer_head *bh = sbi->s_lvid_bh;
        struct logicalVolIntegrityDesc *lvid;
        struct logicalVolIntegrityDescImpUse *lvidiu;

        if (!bh)
                return;
        lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
        lvidiu = udf_sb_lvidiu(sb);
        if (!lvidiu)
                return;

        mutex_lock(&sbi->s_alloc_mutex);
        lvidiu->impIdent.identSuffix[0] = UDF_OS_CLASS_UNIX;
        lvidiu->impIdent.identSuffix[1] = UDF_OS_ID_LINUX;
        if (UDF_MAX_WRITE_VERSION > le16_to_cpu(lvidiu->maxUDFWriteRev))
                lvidiu->maxUDFWriteRev = cpu_to_le16(UDF_MAX_WRITE_VERSION);
        if (sbi->s_udfrev > le16_to_cpu(lvidiu->minUDFReadRev))
                lvidiu->minUDFReadRev = cpu_to_le16(sbi->s_udfrev);
        if (sbi->s_udfrev > le16_to_cpu(lvidiu->minUDFWriteRev))
                lvidiu->minUDFWriteRev = cpu_to_le16(sbi->s_udfrev);
        if (!UDF_QUERY_FLAG(sb, UDF_FLAG_INCONSISTENT))
                lvid->integrityType = cpu_to_le32(LVID_INTEGRITY_TYPE_CLOSE);

        /*
         * We set buffer uptodate unconditionally here to avoid spurious
         * warnings from mark_buffer_dirty() when previous EIO has marked
         * the buffer as !uptodate
         */
        set_buffer_uptodate(bh);
        udf_finalize_lvid(lvid);
        mark_buffer_dirty(bh);
        sbi->s_lvid_dirty = 0;
        mutex_unlock(&sbi->s_alloc_mutex);
        /* Make closing of filesystem visible on the media immediately */
        sync_dirty_buffer(bh);
}

u64 lvid_get_unique_id(struct super_block *sb)
{
        struct buffer_head *bh;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct logicalVolIntegrityDesc *lvid;
        struct logicalVolHeaderDesc *lvhd;
        u64 uniqueID;
        u64 ret;

        bh = sbi->s_lvid_bh;
        if (!bh)
                return 0;

        lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
        lvhd = (struct logicalVolHeaderDesc *)lvid->logicalVolContentsUse;

        mutex_lock(&sbi->s_alloc_mutex);
        ret = uniqueID = le64_to_cpu(lvhd->uniqueID);
        if (!(++uniqueID & 0xFFFFFFFF))
                uniqueID += 16;
        lvhd->uniqueID = cpu_to_le64(uniqueID);
        udf_updated_lvid(sb);
        mutex_unlock(&sbi->s_alloc_mutex);

        return ret;
}

static int udf_fill_super(struct super_block *sb, void *options, int silent)
{
        int ret = -EINVAL;
        struct inode *inode = NULL;
        struct udf_options uopt;
        struct kernel_lb_addr rootdir, fileset;
        struct udf_sb_info *sbi;
        bool lvid_open = false;

        uopt.flags = (1 << UDF_FLAG_USE_AD_IN_ICB) | (1 << UDF_FLAG_STRICT);
        /* By default we'll use overflow[ug]id when UDF inode [ug]id == -1 */
        uopt.uid = make_kuid(current_user_ns(), overflowuid);
        uopt.gid = make_kgid(current_user_ns(), overflowgid);
        uopt.umask = 0;
        uopt.fmode = UDF_INVALID_MODE;
        uopt.dmode = UDF_INVALID_MODE;
        uopt.nls_map = NULL;

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

        sb->s_fs_info = sbi;

        mutex_init(&sbi->s_alloc_mutex);

        if (!udf_parse_options((char *)options, &uopt, false))
                goto parse_options_failure;

        if (uopt.flags & (1 << UDF_FLAG_UTF8) &&
            uopt.flags & (1 << UDF_FLAG_NLS_MAP)) {
                udf_err(sb, "utf8 cannot be combined with iocharset\n");
                goto parse_options_failure;
        }
        if ((uopt.flags & (1 << UDF_FLAG_NLS_MAP)) && !uopt.nls_map) {
                uopt.nls_map = load_nls_default();
                if (!uopt.nls_map)
                        uopt.flags &= ~(1 << UDF_FLAG_NLS_MAP);
                else
                        udf_debug("Using default NLS map\n");
        }
        if (!(uopt.flags & (1 << UDF_FLAG_NLS_MAP)))
                uopt.flags |= (1 << UDF_FLAG_UTF8);

        fileset.logicalBlockNum = 0xFFFFFFFF;
        fileset.partitionReferenceNum = 0xFFFF;

        sbi->s_flags = uopt.flags;
        sbi->s_uid = uopt.uid;
        sbi->s_gid = uopt.gid;
        sbi->s_umask = uopt.umask;
        sbi->s_fmode = uopt.fmode;
        sbi->s_dmode = uopt.dmode;
        sbi->s_nls_map = uopt.nls_map;
        rwlock_init(&sbi->s_cred_lock);

        if (uopt.session == 0xFFFFFFFF)
                sbi->s_session = udf_get_last_session(sb);
        else
                sbi->s_session = uopt.session;

        udf_debug("Multi-session=%d\n", sbi->s_session);

        /* Fill in the rest of the superblock */
        sb->s_op = &udf_sb_ops;
        sb->s_export_op = &udf_export_ops;

        sb->s_magic = UDF_SUPER_MAGIC;
        sb->s_time_gran = 1000;

        if (uopt.flags & (1 << UDF_FLAG_BLOCKSIZE_SET)) {
                ret = udf_load_vrs(sb, &uopt, silent, &fileset);
        } else {
                uopt.blocksize = bdev_logical_block_size(sb->s_bdev);
                while (uopt.blocksize <= 4096) {
                        ret = udf_load_vrs(sb, &uopt, silent, &fileset);
                        if (ret < 0) {
                                if (!silent && ret != -EACCES) {
                                        pr_notice("Scanning with blocksize %u failed\n",
                                                  uopt.blocksize);
                                }
                                brelse(sbi->s_lvid_bh);
                                sbi->s_lvid_bh = NULL;
                                /*
                                 * EACCES is special - we want to propagate to
                                 * upper layers that we cannot handle RW mount.
                                 */
                                if (ret == -EACCES)
                                        break;
                        } else
                                break;

                        uopt.blocksize <<= 1;
                }
        }
        if (ret < 0) {
                if (ret == -EAGAIN) {
                        udf_warn(sb, "No partition found (1)\n");
                        ret = -EINVAL;
                }
                goto error_out;
        }

        udf_debug("Lastblock=%u\n", sbi->s_last_block);

        if (sbi->s_lvid_bh) {
                struct logicalVolIntegrityDescImpUse *lvidiu =
                                                        udf_sb_lvidiu(sb);
                uint16_t minUDFReadRev;
                uint16_t minUDFWriteRev;

                if (!lvidiu) {
                        ret = -EINVAL;
                        goto error_out;
                }
                minUDFReadRev = le16_to_cpu(lvidiu->minUDFReadRev);
                minUDFWriteRev = le16_to_cpu(lvidiu->minUDFWriteRev);
                if (minUDFReadRev > UDF_MAX_READ_VERSION) {
                        udf_err(sb, "minUDFReadRev=%x (max is %x)\n",
                                minUDFReadRev,
                                UDF_MAX_READ_VERSION);
                        ret = -EINVAL;
                        goto error_out;
                } else if (minUDFWriteRev > UDF_MAX_WRITE_VERSION) {
                        if (!sb_rdonly(sb)) {
                                ret = -EACCES;
                                goto error_out;
                        }
                        UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
                }

                sbi->s_udfrev = minUDFWriteRev;

                if (minUDFReadRev >= UDF_VERS_USE_EXTENDED_FE)
                        UDF_SET_FLAG(sb, UDF_FLAG_USE_EXTENDED_FE);
                if (minUDFReadRev >= UDF_VERS_USE_STREAMS)
                        UDF_SET_FLAG(sb, UDF_FLAG_USE_STREAMS);
        }

        if (!sbi->s_partitions) {
                udf_warn(sb, "No partition found (2)\n");
                ret = -EINVAL;
                goto error_out;
        }

        if (sbi->s_partmaps[sbi->s_partition].s_partition_flags &
                        UDF_PART_FLAG_READ_ONLY) {
                if (!sb_rdonly(sb)) {
                        ret = -EACCES;
                        goto error_out;
                }
                UDF_SET_FLAG(sb, UDF_FLAG_RW_INCOMPAT);
        }

        ret = udf_find_fileset(sb, &fileset, &rootdir);
        if (ret < 0) {
                udf_warn(sb, "No fileset found\n");
                goto error_out;
        }

        if (!silent) {
                struct timestamp ts;
                udf_time_to_disk_stamp(&ts, sbi->s_record_time);
                udf_info("Mounting volume '%s', timestamp %04u/%02u/%02u %02u:%02u (%x)\n",
                         sbi->s_volume_ident,
                         le16_to_cpu(ts.year), ts.month, ts.day,
                         ts.hour, ts.minute, le16_to_cpu(ts.typeAndTimezone));
        }
        if (!sb_rdonly(sb)) {
                udf_open_lvid(sb);
                lvid_open = true;
        }

        /* Assign the root inode */
        /* assign inodes by physical block number */
        /* perhaps it's not extensible enough, but for now ... */
        inode = udf_iget(sb, &rootdir);
        if (IS_ERR(inode)) {
                udf_err(sb, "Error in udf_iget, block=%u, partition=%u\n",
                       rootdir.logicalBlockNum, rootdir.partitionReferenceNum);
                ret = PTR_ERR(inode);
                goto error_out;
        }

        /* Allocate a dentry for the root inode */
        sb->s_root = d_make_root(inode);
        if (!sb->s_root) {
                udf_err(sb, "Couldn't allocate root dentry\n");
                ret = -ENOMEM;
                goto error_out;
        }
        sb->s_maxbytes = MAX_LFS_FILESIZE;
        sb->s_max_links = UDF_MAX_LINKS;
        return 0;

error_out:
        iput(sbi->s_vat_inode);
parse_options_failure:
        if (uopt.nls_map)
                unload_nls(uopt.nls_map);
        if (lvid_open)
                udf_close_lvid(sb);
        brelse(sbi->s_lvid_bh);
        udf_sb_free_partitions(sb);
        kfree(sbi);
        sb->s_fs_info = NULL;

        return ret;
}

void _udf_err(struct super_block *sb, const char *function,
              const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, fmt);

        vaf.fmt = fmt;
        vaf.va = &args;

        pr_err("error (device %s): %s: %pV", sb->s_id, function, &vaf);

        va_end(args);
}

void _udf_warn(struct super_block *sb, const char *function,
               const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, fmt);

        vaf.fmt = fmt;
        vaf.va = &args;

        pr_warn("warning (device %s): %s: %pV", sb->s_id, function, &vaf);

        va_end(args);
}

static void udf_put_super(struct super_block *sb)
{
        struct udf_sb_info *sbi;

        sbi = UDF_SB(sb);

        iput(sbi->s_vat_inode);
        if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP))
                unload_nls(sbi->s_nls_map);
        if (!sb_rdonly(sb))
                udf_close_lvid(sb);
        brelse(sbi->s_lvid_bh);
        udf_sb_free_partitions(sb);
        mutex_destroy(&sbi->s_alloc_mutex);
        kfree(sb->s_fs_info);
        sb->s_fs_info = NULL;
}

static int udf_sync_fs(struct super_block *sb, int wait)
{
        struct udf_sb_info *sbi = UDF_SB(sb);

        mutex_lock(&sbi->s_alloc_mutex);
        if (sbi->s_lvid_dirty) {
                struct buffer_head *bh = sbi->s_lvid_bh;
                struct logicalVolIntegrityDesc *lvid;

                lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
                udf_finalize_lvid(lvid);

                /*
                 * Blockdevice will be synced later so we don't have to submit
                 * the buffer for IO
                 */
                mark_buffer_dirty(bh);
                sbi->s_lvid_dirty = 0;
        }
        mutex_unlock(&sbi->s_alloc_mutex);

        return 0;
}

static int udf_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct logicalVolIntegrityDescImpUse *lvidiu;
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

        lvidiu = udf_sb_lvidiu(sb);
        buf->f_type = UDF_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = sbi->s_partmaps[sbi->s_partition].s_partition_len;
        buf->f_bfree = udf_count_free(sb);
        buf->f_bavail = buf->f_bfree;
        /*
         * Let's pretend each free block is also a free 'inode' since UDF does
         * not have separate preallocated table of inodes.
         */
        buf->f_files = (lvidiu != NULL ? (le32_to_cpu(lvidiu->numFiles) +
                                          le32_to_cpu(lvidiu->numDirs)) : 0)
                        + buf->f_bfree;
        buf->f_ffree = buf->f_bfree;
        buf->f_namelen = UDF_NAME_LEN;
        buf->f_fsid = u64_to_fsid(id);

        return 0;
}

static unsigned int udf_count_free_bitmap(struct super_block *sb,
                                          struct udf_bitmap *bitmap)
{
        struct buffer_head *bh = NULL;
        unsigned int accum = 0;
        int index;
        udf_pblk_t block = 0, newblock;
        struct kernel_lb_addr loc;
        uint32_t bytes;
        uint8_t *ptr;
        uint16_t ident;
        struct spaceBitmapDesc *bm;

        loc.logicalBlockNum = bitmap->s_extPosition;
        loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
        bh = udf_read_ptagged(sb, &loc, 0, &ident);

        if (!bh) {
                udf_err(sb, "udf_count_free failed\n");
                goto out;
        } else if (ident != TAG_IDENT_SBD) {
                brelse(bh);
                udf_err(sb, "udf_count_free failed\n");
                goto out;
        }

        bm = (struct spaceBitmapDesc *)bh->b_data;
        bytes = le32_to_cpu(bm->numOfBytes);
        index = sizeof(struct spaceBitmapDesc); /* offset in first block only */
        ptr = (uint8_t *)bh->b_data;

        while (bytes > 0) {
                u32 cur_bytes = min_t(u32, bytes, sb->s_blocksize - index);
                accum += bitmap_weight((const unsigned long *)(ptr + index),
                                        cur_bytes * 8);
                bytes -= cur_bytes;
                if (bytes) {
                        brelse(bh);
                        newblock = udf_get_lb_pblock(sb, &loc, ++block);
                        bh = udf_tread(sb, newblock);
                        if (!bh) {
                                udf_debug("read failed\n");
                                goto out;
                        }
                        index = 0;
                        ptr = (uint8_t *)bh->b_data;
                }
        }
        brelse(bh);
out:
        return accum;
}

static unsigned int udf_count_free_table(struct super_block *sb,
                                         struct inode *table)
{
        unsigned int accum = 0;
        uint32_t elen;
        struct kernel_lb_addr eloc;
        int8_t etype;
        struct extent_position epos;

        mutex_lock(&UDF_SB(sb)->s_alloc_mutex);
        epos.block = UDF_I(table)->i_location;
        epos.offset = sizeof(struct unallocSpaceEntry);
        epos.bh = NULL;

        while ((etype = udf_next_aext(table, &epos, &eloc, &elen, 1)) != -1)
                accum += (elen >> table->i_sb->s_blocksize_bits);

        brelse(epos.bh);
        mutex_unlock(&UDF_SB(sb)->s_alloc_mutex);

        return accum;
}

static unsigned int udf_count_free(struct super_block *sb)
{
        unsigned int accum = 0;
        struct udf_sb_info *sbi = UDF_SB(sb);
        struct udf_part_map *map;
        unsigned int part = sbi->s_partition;
        int ptype = sbi->s_partmaps[part].s_partition_type;

        if (ptype == UDF_METADATA_MAP25) {
                part = sbi->s_partmaps[part].s_type_specific.s_metadata.
                                                        s_phys_partition_ref;
        } else if (ptype == UDF_VIRTUAL_MAP15 || ptype == UDF_VIRTUAL_MAP20) {
                /*
                 * Filesystems with VAT are append-only and we cannot write to
                 * them. Let's just report 0 here.
                 */
                return 0;
        }

        if (sbi->s_lvid_bh) {
                struct logicalVolIntegrityDesc *lvid =
                        (struct logicalVolIntegrityDesc *)
                        sbi->s_lvid_bh->b_data;
                if (le32_to_cpu(lvid->numOfPartitions) > part) {
                        accum = le32_to_cpu(
                                        lvid->freeSpaceTable[part]);
                        if (accum == 0xFFFFFFFF)
                                accum = 0;
                }
        }

        if (accum)
                return accum;

        map = &sbi->s_partmaps[part];
        if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
                accum += udf_count_free_bitmap(sb,
                                               map->s_uspace.s_bitmap);
        }
        if (accum)
                return accum;

        if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE) {
                accum += udf_count_free_table(sb,
                                              map->s_uspace.s_table);
        }
        return accum;
}

MODULE_AUTHOR("Ben Fennema");
MODULE_DESCRIPTION("Universal Disk Format Filesystem");
MODULE_LICENSE("GPL");
module_init(init_udf_fs)
module_exit(exit_udf_fs)