/*
   *  linux/fs/adfs/super.c
   *
   *  Copyright (C) 1997-1999 Russell King
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #include <linux/module.h>

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

  #include <linux/parser.h>

  #include <linux/mount.h>
  #include <linux/seq_file.h>

  #include <linux/slab.h>

  #include <linux/statfs.h>

  #include <linux/user_namespace.h>

  #include "adfs.h"
  #include "dir_f.h"
  #include "dir_fplus.h"

  #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
  #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)

  void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
  {
  	char error_buf[128];
  	va_list args;
  
  	va_start(args, fmt);

  	vsnprintf(error_buf, sizeof(error_buf), fmt, args);

  	va_end(args);
  
  	printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %s
  ",
  		sb->s_id, function ? ": " : "",
  		function ? function : "", error_buf);
  }
  
  static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
  {
  	int i;
  
  	/* sector size must be 256, 512 or 1024 bytes */
  	if (dr->log2secsize != 8 &&
  	    dr->log2secsize != 9 &&
  	    dr->log2secsize != 10)
  		return 1;
  
  	/* idlen must be at least log2secsize + 3 */
  	if (dr->idlen < dr->log2secsize + 3)
  		return 1;
  
  	/* we cannot have such a large disc that we
  	 * are unable to represent sector offsets in
  	 * 32 bits.  This works out at 2.0 TB.
  	 */
  	if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
  		return 1;
  
  	/* idlen must be no greater than 19 v2 [1.0] */
  	if (dr->idlen > 19)
  		return 1;
  
  	/* reserved bytes should be zero */
  	for (i = 0; i < sizeof(dr->unused52); i++)
  		if (dr->unused52[i] != 0)
  			return 1;
  
  	return 0;
  }
  
  static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
  {
  	unsigned int v0, v1, v2, v3;
  	int i;
  
  	v0 = v1 = v2 = v3 = 0;
  	for (i = sb->s_blocksize - 4; i; i -= 4) {
  		v0 += map[i]     + (v3 >> 8);
  		v3 &= 0xff;
  		v1 += map[i + 1] + (v0 >> 8);
  		v0 &= 0xff;
  		v2 += map[i + 2] + (v1 >> 8);
  		v1 &= 0xff;
  		v3 += map[i + 3] + (v2 >> 8);
  		v2 &= 0xff;
  	}
  	v0 +=           v3 >> 8;
  	v1 += map[1] + (v0 >> 8);
  	v2 += map[2] + (v1 >> 8);
  	v3 += map[3] + (v2 >> 8);
  
  	return v0 ^ v1 ^ v2 ^ v3;
  }
  
  static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
  {
  	unsigned char crosscheck = 0, zonecheck = 1;
  	int i;
  
  	for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
  		unsigned char *map;
  
  		map = dm[i].dm_bh->b_data;
  
  		if (adfs_calczonecheck(sb, map) != map[0]) {
  			adfs_error(sb, "zone %d fails zonecheck", i);
  			zonecheck = 0;
  		}
  		crosscheck ^= map[3];
  	}
  	if (crosscheck != 0xff)
  		adfs_error(sb, "crosscheck != 0xff");
  	return crosscheck == 0xff && zonecheck;
  }
  
  static void adfs_put_super(struct super_block *sb)
  {
  	int i;
  	struct adfs_sb_info *asb = ADFS_SB(sb);
  
  	for (i = 0; i < asb->s_map_size; i++)
  		brelse(asb->s_map[i].dm_bh);
  	kfree(asb->s_map);

  	kfree_rcu(asb, rcu);

  }

  static int adfs_show_options(struct seq_file *seq, struct dentry *root)

  {

  	struct adfs_sb_info *asb = ADFS_SB(root->d_sb);

  	if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
  		seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
  	if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
  		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));

  	if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
  		seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
  	if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
  		seq_printf(seq, ",othmask=%o", asb->s_other_mask);

  	if (asb->s_ftsuffix != 0)
  		seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);

  
  	return 0;
  }

  enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};

  static const match_table_t tokens = {

  	{Opt_uid, "uid=%u"},
  	{Opt_gid, "gid=%u"},
  	{Opt_ownmask, "ownmask=%o"},
  	{Opt_othmask, "othmask=%o"},

  	{Opt_ftsuffix, "ftsuffix=%u"},

  	{Opt_err, NULL}
  };
  
  static int parse_options(struct super_block *sb, char *options)
  {
  	char *p;
  	struct adfs_sb_info *asb = ADFS_SB(sb);
  	int option;
  
  	if (!options)
  		return 0;
  
  	while ((p = strsep(&options, ",")) != NULL) {
  		substring_t args[MAX_OPT_ARGS];
  		int token;
  		if (!*p)
  			continue;
  
  		token = match_token(p, tokens, args);
  		switch (token) {
  		case Opt_uid:
  			if (match_int(args, &option))
  				return -EINVAL;

  			asb->s_uid = make_kuid(current_user_ns(), option);
  			if (!uid_valid(asb->s_uid))
  				return -EINVAL;

  			break;
  		case Opt_gid:
  			if (match_int(args, &option))
  				return -EINVAL;

  			asb->s_gid = make_kgid(current_user_ns(), option);
  			if (!gid_valid(asb->s_gid))
  				return -EINVAL;

  			break;
  		case Opt_ownmask:
  			if (match_octal(args, &option))
  				return -EINVAL;
  			asb->s_owner_mask = option;
  			break;
  		case Opt_othmask:
  			if (match_octal(args, &option))
  				return -EINVAL;
  			asb->s_other_mask = option;
  			break;

  		case Opt_ftsuffix:
  			if (match_int(args, &option))
  				return -EINVAL;
  			asb->s_ftsuffix = option;
  			break;

  		default:
  			printk("ADFS-fs: unrecognised mount option \"%s\" "
  					"or missing value
  ", p);
  			return -EINVAL;
  		}
  	}
  	return 0;
  }
  
  static int adfs_remount(struct super_block *sb, int *flags, char *data)
  {

  	sync_filesystem(sb);

  	*flags |= MS_NODIRATIME;
  	return parse_options(sb, data);
  }

  static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)

  {

  	struct super_block *sb = dentry->d_sb;
  	struct adfs_sb_info *sbi = ADFS_SB(sb);
  	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

  
  	buf->f_type    = ADFS_SUPER_MAGIC;

  	buf->f_namelen = sbi->s_namelen;
  	buf->f_bsize   = sb->s_blocksize;
  	buf->f_blocks  = sbi->s_size;
  	buf->f_files   = sbi->s_ids_per_zone * sbi->s_map_size;

  	buf->f_bavail  =

  	buf->f_bfree   = adfs_map_free(sb);

  	buf->f_ffree   = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;

  	buf->f_fsid.val[0] = (u32)id;
  	buf->f_fsid.val[1] = (u32)(id >> 32);

  
  	return 0;
  }

  static struct kmem_cache *adfs_inode_cachep;

  
  static struct inode *adfs_alloc_inode(struct super_block *sb)
  {
  	struct adfs_inode_info *ei;

  	ei = kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);

  	if (!ei)
  		return NULL;
  	return &ei->vfs_inode;
  }

  static void adfs_i_callback(struct rcu_head *head)

  {

  	struct inode *inode = container_of(head, struct inode, i_rcu);

  	kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
  }

  static void adfs_destroy_inode(struct inode *inode)
  {
  	call_rcu(&inode->i_rcu, adfs_i_callback);
  }

  static void init_once(void *foo)

  {
  	struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;

  	inode_init_once(&ei->vfs_inode);

  }

  static int __init init_inodecache(void)

  {
  	adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
  					     sizeof(struct adfs_inode_info),

  					     0, (SLAB_RECLAIM_ACCOUNT|

  						SLAB_MEM_SPREAD|SLAB_ACCOUNT),

  					     init_once);

  	if (adfs_inode_cachep == NULL)
  		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(adfs_inode_cachep);

  }

  static const struct super_operations adfs_sops = {

  	.alloc_inode	= adfs_alloc_inode,
  	.destroy_inode	= adfs_destroy_inode,
  	.write_inode	= adfs_write_inode,
  	.put_super	= adfs_put_super,
  	.statfs		= adfs_statfs,
  	.remount_fs	= adfs_remount,

  	.show_options	= adfs_show_options,

  };
  
  static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
  {
  	struct adfs_discmap *dm;
  	unsigned int map_addr, zone_size, nzones;
  	int i, zone;
  	struct adfs_sb_info *asb = ADFS_SB(sb);
  
  	nzones    = asb->s_map_size;
  	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
  	map_addr  = (nzones >> 1) * zone_size -
  		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
  	map_addr  = signed_asl(map_addr, asb->s_map2blk);
  
  	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
  
  	dm = kmalloc(nzones * sizeof(*dm), GFP_KERNEL);
  	if (dm == NULL) {
  		adfs_error(sb, "not enough memory");

  		return ERR_PTR(-ENOMEM);

  	}
  
  	for (zone = 0; zone < nzones; zone++, map_addr++) {
  		dm[zone].dm_startbit = 0;
  		dm[zone].dm_endbit   = zone_size;
  		dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
  		dm[zone].dm_bh       = sb_bread(sb, map_addr);
  
  		if (!dm[zone].dm_bh) {
  			adfs_error(sb, "unable to read map");
  			goto error_free;
  		}
  	}
  
  	/* adjust the limits for the first and last map zones */
  	i = zone - 1;
  	dm[0].dm_startblk = 0;
  	dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
  	dm[i].dm_endbit   = (le32_to_cpu(dr->disc_size_high) << (32 - dr->log2bpmb)) +
  			    (le32_to_cpu(dr->disc_size) >> dr->log2bpmb) +
  			    (ADFS_DR_SIZE_BITS - i * zone_size);
  
  	if (adfs_checkmap(sb, dm))
  		return dm;

  	adfs_error(sb, "map corrupted");

  
  error_free:
  	while (--zone >= 0)
  		brelse(dm[zone].dm_bh);
  
  	kfree(dm);

  	return ERR_PTR(-EIO);

  }
  
  static inline unsigned long adfs_discsize(struct adfs_discrecord *dr, int block_bits)
  {
  	unsigned long discsize;
  
  	discsize  = le32_to_cpu(dr->disc_size_high) << (32 - block_bits);
  	discsize |= le32_to_cpu(dr->disc_size) >> block_bits;
  
  	return discsize;
  }
  
  static int adfs_fill_super(struct super_block *sb, void *data, int silent)
  {
  	struct adfs_discrecord *dr;
  	struct buffer_head *bh;
  	struct object_info root_obj;
  	unsigned char *b_data;
  	struct adfs_sb_info *asb;
  	struct inode *root;

  	int ret = -EINVAL;

  
  	sb->s_flags |= MS_NODIRATIME;

  	asb = kzalloc(sizeof(*asb), GFP_KERNEL);

  	if (!asb)

  		return -ENOMEM;
  	sb->s_fs_info = asb;

  
  	/* set default options */

  	asb->s_uid = GLOBAL_ROOT_UID;
  	asb->s_gid = GLOBAL_ROOT_GID;

  	asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
  	asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;

  	asb->s_ftsuffix = 0;

  
  	if (parse_options(sb, data))
  		goto error;
  
  	sb_set_blocksize(sb, BLOCK_SIZE);
  	if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
  		adfs_error(sb, "unable to read superblock");

  		ret = -EIO;

  		goto error;
  	}
  
  	b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
  
  	if (adfs_checkbblk(b_data)) {
  		if (!silent)
  			printk("VFS: Can't find an adfs filesystem on dev "
  				"%s.
  ", sb->s_id);

  		ret = -EINVAL;

  		goto error_free_bh;
  	}
  
  	dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
  
  	/*
  	 * Do some sanity checks on the ADFS disc record
  	 */
  	if (adfs_checkdiscrecord(dr)) {
  		if (!silent)
  			printk("VPS: Can't find an adfs filesystem on dev "
  				"%s.
  ", sb->s_id);

  		ret = -EINVAL;

  		goto error_free_bh;
  	}
  
  	brelse(bh);
  	if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
  		bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
  		if (!bh) {
  			adfs_error(sb, "couldn't read superblock on "
  				"2nd try.");

  			ret = -EIO;

  			goto error;
  		}
  		b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
  		if (adfs_checkbblk(b_data)) {
  			adfs_error(sb, "disc record mismatch, very weird!");

  			ret = -EINVAL;

  			goto error_free_bh;
  		}
  		dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
  	} else {
  		if (!silent)
  			printk(KERN_ERR "VFS: Unsupported blocksize on dev "
  				"%s.
  ", sb->s_id);

  		ret = -EINVAL;

  		goto error;
  	}
  
  	/*
  	 * blocksize on this device should now be set to the ADFS log2secsize
  	 */
  
  	sb->s_magic		= ADFS_SUPER_MAGIC;
  	asb->s_idlen		= dr->idlen;
  	asb->s_map_size		= dr->nzones | (dr->nzones_high << 8);
  	asb->s_map2blk		= dr->log2bpmb - dr->log2secsize;
  	asb->s_size    		= adfs_discsize(dr, sb->s_blocksize_bits);
  	asb->s_version 		= dr->format_version;
  	asb->s_log2sharesize	= dr->log2sharesize;

  	asb->s_map = adfs_read_map(sb, dr);

  	if (IS_ERR(asb->s_map)) {
  		ret =  PTR_ERR(asb->s_map);

  		goto error_free_bh;

  	}

  
  	brelse(bh);
  
  	/*
  	 * set up enough so that we can read an inode
  	 */
  	sb->s_op = &adfs_sops;
  
  	dr = (struct adfs_discrecord *)(asb->s_map[0].dm_bh->b_data + 4);
  
  	root_obj.parent_id = root_obj.file_id = le32_to_cpu(dr->root);
  	root_obj.name_len  = 0;

  	/* Set root object date as 01 Jan 1987 00:00:00 */
  	root_obj.loadaddr  = 0xfff0003f;
  	root_obj.execaddr  = 0xec22c000;

  	root_obj.size	   = ADFS_NEWDIR_SIZE;
  	root_obj.attr	   = ADFS_NDA_DIRECTORY   | ADFS_NDA_OWNER_READ |
  			     ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;

  	root_obj.filetype  = -1;

  
  	/*
  	 * If this is a F+ disk with variable length directories,
  	 * get the root_size from the disc record.
  	 */
  	if (asb->s_version) {
  		root_obj.size = le32_to_cpu(dr->root_size);
  		asb->s_dir     = &adfs_fplus_dir_ops;
  		asb->s_namelen = ADFS_FPLUS_NAME_LEN;
  	} else {
  		asb->s_dir     = &adfs_f_dir_ops;
  		asb->s_namelen = ADFS_F_NAME_LEN;
  	}

  	/*
  	 * ,xyz hex filetype suffix may be added by driver
  	 * to files that have valid RISC OS filetype
  	 */
  	if (asb->s_ftsuffix)
  		asb->s_namelen += 4;

  	sb->s_d_op = &adfs_dentry_operations;

  	root = adfs_iget(sb, &root_obj);

  	sb->s_root = d_make_root(root);

  	if (!sb->s_root) {
  		int i;

  		for (i = 0; i < asb->s_map_size; i++)
  			brelse(asb->s_map[i].dm_bh);
  		kfree(asb->s_map);
  		adfs_error(sb, "get root inode failed
  ");

  		ret = -EIO;

  		goto error;

  	}

  	return 0;
  
  error_free_bh:
  	brelse(bh);
  error:
  	sb->s_fs_info = NULL;
  	kfree(asb);

  	return ret;

  }

  static struct dentry *adfs_mount(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data)

  {

  	return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);

  }
  
  static struct file_system_type adfs_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "adfs",

  	.mount		= adfs_mount,

  	.kill_sb	= kill_block_super,
  	.fs_flags	= FS_REQUIRES_DEV,
  };

  MODULE_ALIAS_FS("adfs");

  
  static int __init init_adfs_fs(void)
  {
  	int err = init_inodecache();
  	if (err)
  		goto out1;
  	err = register_filesystem(&adfs_fs_type);
  	if (err)
  		goto out;
  	return 0;
  out:
  	destroy_inodecache();
  out1:
  	return err;
  }
  
  static void __exit exit_adfs_fs(void)
  {
  	unregister_filesystem(&adfs_fs_type);
  	destroy_inodecache();
  }
  
  module_init(init_adfs_fs)
  module_exit(exit_adfs_fs)

  MODULE_LICENSE("GPL");