text: /*
   *  linux/fs/affs/inode.c
   *
   *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   *
   *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   *
   *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
   *
   *  (C) 1991  Linus Torvalds - minix filesystem
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/statfs.h>
  #include <linux/parser.h>
  #include <linux/magic.h>
  #include <linux/sched.h>
  #include <linux/cred.h>
  #include <linux/slab.h>
  #include <linux/writeback.h>
  #include <linux/blkdev.h>
  #include <linux/seq_file.h>
  #include <linux/iversion.h>
  #include "affs.h"
  
  static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
  static int affs_show_options(struct seq_file *m, struct dentry *root);
  static int affs_remount (struct super_block *sb, int *flags, char *data);
  
  static void
  affs_commit_super(struct super_block *sb, int wait)
  {
  	struct affs_sb_info *sbi = AFFS_SB(sb);
  	struct buffer_head *bh = sbi->s_root_bh;
  	struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
  
  	lock_buffer(bh);
  	affs_secs_to_datestamp(ktime_get_real_seconds(), &tail->disk_change);
  	affs_fix_checksum(sb, bh);
  	unlock_buffer(bh);
  
  	mark_buffer_dirty(bh);
  	if (wait)
  		sync_dirty_buffer(bh);
  }
  
  static void
  affs_put_super(struct super_block *sb)
  {
  	struct affs_sb_info *sbi = AFFS_SB(sb);
  	pr_debug("%s()\n", __func__);
  
  	cancel_delayed_work_sync(&sbi->sb_work);
  }
  
  static int
  affs_sync_fs(struct super_block *sb, int wait)
  {
  	affs_commit_super(sb, wait);
  	return 0;
  }
  
  static void flush_superblock(struct work_struct *work)
  {
  	struct affs_sb_info *sbi;
  	struct super_block *sb;
  
  	sbi = container_of(work, struct affs_sb_info, sb_work.work);
  	sb = sbi->sb;
  
  	spin_lock(&sbi->work_lock);
  	sbi->work_queued = 0;
  	spin_unlock(&sbi->work_lock);
  
  	affs_commit_super(sb, 1);
  }
  
  void affs_mark_sb_dirty(struct super_block *sb)
  {
  	struct affs_sb_info *sbi = AFFS_SB(sb);
  	unsigned long delay;
  
  	if (sb_rdonly(sb))
  	       return;
  
  	spin_lock(&sbi->work_lock);
  	if (!sbi->work_queued) {
  	       delay = msecs_to_jiffies(dirty_writeback_interval * 10);
  	       queue_delayed_work(system_long_wq, &sbi->sb_work, delay);
  	       sbi->work_queued = 1;
  	}
  	spin_unlock(&sbi->work_lock);
  }
  
  static struct kmem_cache * affs_inode_cachep;
  
  static struct inode *affs_alloc_inode(struct super_block *sb)
  {
  	struct affs_inode_info *i;
  
  	i = kmem_cache_alloc(affs_inode_cachep, GFP_KERNEL);
  	if (!i)
  		return NULL;
  
  	inode_set_iversion(&i->vfs_inode, 1);
  	i->i_lc = NULL;
  	i->i_ext_bh = NULL;
  	i->i_pa_cnt = 0;
  
  	return &i->vfs_inode;
  }
  
  static void affs_i_callback(struct rcu_head *head)
  {
  	struct inode *inode = container_of(head, struct inode, i_rcu);
  	kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
  }
  
  static void affs_destroy_inode(struct inode *inode)
  {
  	call_rcu(&inode->i_rcu, affs_i_callback);
  }
  
  static void init_once(void *foo)
  {
  	struct affs_inode_info *ei = (struct affs_inode_info *) foo;
  
  	sema_init(&ei->i_link_lock, 1);
  	sema_init(&ei->i_ext_lock, 1);
  	inode_init_once(&ei->vfs_inode);
  }
  
  static int __init init_inodecache(void)
  {
  	affs_inode_cachep = kmem_cache_create("affs_inode_cache",
  					     sizeof(struct affs_inode_info),
  					     0, (SLAB_RECLAIM_ACCOUNT|
  						SLAB_MEM_SPREAD|SLAB_ACCOUNT),
  					     init_once);
  	if (affs_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(affs_inode_cachep);
  }
  
  static const struct super_operations affs_sops = {
  	.alloc_inode	= affs_alloc_inode,
  	.destroy_inode	= affs_destroy_inode,
  	.write_inode	= affs_write_inode,
  	.evict_inode	= affs_evict_inode,
  	.put_super	= affs_put_super,
  	.sync_fs	= affs_sync_fs,
  	.statfs		= affs_statfs,
  	.remount_fs	= affs_remount,
  	.show_options	= affs_show_options,
  };
  
  enum {
  	Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
  	Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
  	Opt_verbose, Opt_volume, Opt_ignore, Opt_err,
  };
  
  static const match_table_t tokens = {
  	{Opt_bs, "bs=%u"},
  	{Opt_mode, "mode=%o"},
  	{Opt_mufs, "mufs"},
  	{Opt_notruncate, "nofilenametruncate"},
  	{Opt_prefix, "prefix=%s"},
  	{Opt_protect, "protect"},
  	{Opt_reserved, "reserved=%u"},
  	{Opt_root, "root=%u"},
  	{Opt_setgid, "setgid=%u"},
  	{Opt_setuid, "setuid=%u"},
  	{Opt_verbose, "verbose"},
  	{Opt_volume, "volume=%s"},
  	{Opt_ignore, "grpquota"},
  	{Opt_ignore, "noquota"},
  	{Opt_ignore, "quota"},
  	{Opt_ignore, "usrquota"},
  	{Opt_err, NULL},
  };
  
  static int
  parse_options(char *options, kuid_t *uid, kgid_t *gid, int *mode, int *reserved, s32 *root,
  		int *blocksize, char **prefix, char *volume, unsigned long *mount_opts)
  {
  	char *p;
  	substring_t args[MAX_OPT_ARGS];
  
  	/* Fill in defaults */
  
  	*uid        = current_uid();
  	*gid        = current_gid();
  	*reserved   = 2;
  	*root       = -1;
  	*blocksize  = -1;
  	volume[0]   = ':';
  	volume[1]   = 0;
  	*mount_opts = 0;
  	if (!options)
  		return 1;
  
  	while ((p = strsep(&options, ",")) != NULL) {
  		int token, n, option;
  		if (!*p)
  			continue;
  
  		token = match_token(p, tokens, args);
  		switch (token) {
  		case Opt_bs:
  			if (match_int(&args[0], &n))
  				return 0;
  			if (n != 512 && n != 1024 && n != 2048
  			    && n != 4096) {
  				pr_warn("Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
  				return 0;
  			}
  			*blocksize = n;
  			break;
  		case Opt_mode:
  			if (match_octal(&args[0], &option))
  				return 0;
  			*mode = option & 0777;
  			affs_set_opt(*mount_opts, SF_SETMODE);
  			break;
  		case Opt_mufs:
  			affs_set_opt(*mount_opts, SF_MUFS);
  			break;
  		case Opt_notruncate:
  			affs_set_opt(*mount_opts, SF_NO_TRUNCATE);
  			break;
  		case Opt_prefix:
  			kfree(*prefix);
  			*prefix = match_strdup(&args[0]);
  			if (!*prefix)
  				return 0;
  			affs_set_opt(*mount_opts, SF_PREFIX);
  			break;
  		case Opt_protect:
  			affs_set_opt(*mount_opts, SF_IMMUTABLE);
  			break;
  		case Opt_reserved:
  			if (match_int(&args[0], reserved))
  				return 0;
  			break;
  		case Opt_root:
  			if (match_int(&args[0], root))
  				return 0;
  			break;
  		case Opt_setgid:
  			if (match_int(&args[0], &option))
  				return 0;
  			*gid = make_kgid(current_user_ns(), option);
  			if (!gid_valid(*gid))
  				return 0;
  			affs_set_opt(*mount_opts, SF_SETGID);
  			break;
  		case Opt_setuid:
  			if (match_int(&args[0], &option))
  				return 0;
  			*uid = make_kuid(current_user_ns(), option);
  			if (!uid_valid(*uid))
  				return 0;
  			affs_set_opt(*mount_opts, SF_SETUID);
  			break;
  		case Opt_verbose:
  			affs_set_opt(*mount_opts, SF_VERBOSE);
  			break;
  		case Opt_volume: {
  			char *vol = match_strdup(&args[0]);
  			if (!vol)
  				return 0;
  			strlcpy(volume, vol, 32);
  			kfree(vol);
  			break;
  		}
  		case Opt_ignore:
  		 	/* Silently ignore the quota options */
  			break;
  		default:
  			pr_warn("Unrecognized mount option \"%s\" or missing value\n",
  				p);
  			return 0;
  		}
  	}
  	return 1;
  }
  
  static int affs_show_options(struct seq_file *m, struct dentry *root)
  {
  	struct super_block *sb = root->d_sb;
  	struct affs_sb_info *sbi = AFFS_SB(sb);
  
  	if (sb->s_blocksize)
  		seq_printf(m, ",bs=%lu", sb->s_blocksize);
  	if (affs_test_opt(sbi->s_flags, SF_SETMODE))
  		seq_printf(m, ",mode=%o", sbi->s_mode);
  	if (affs_test_opt(sbi->s_flags, SF_MUFS))
  		seq_puts(m, ",mufs");
  	if (affs_test_opt(sbi->s_flags, SF_NO_TRUNCATE))
  		seq_puts(m, ",nofilenametruncate");
  	if (affs_test_opt(sbi->s_flags, SF_PREFIX))
  		seq_printf(m, ",prefix=%s", sbi->s_prefix);
  	if (affs_test_opt(sbi->s_flags, SF_IMMUTABLE))
  		seq_puts(m, ",protect");
  	if (sbi->s_reserved != 2)
  		seq_printf(m, ",reserved=%u", sbi->s_reserved);
  	if (sbi->s_root_block != (sbi->s_reserved + sbi->s_partition_size - 1) / 2)
  		seq_printf(m, ",root=%u", sbi->s_root_block);
  	if (affs_test_opt(sbi->s_flags, SF_SETGID))
  		seq_printf(m, ",setgid=%u",
  			   from_kgid_munged(&init_user_ns, sbi->s_gid));
  	if (affs_test_opt(sbi->s_flags, SF_SETUID))
  		seq_printf(m, ",setuid=%u",
  			   from_kuid_munged(&init_user_ns, sbi->s_uid));
  	if (affs_test_opt(sbi->s_flags, SF_VERBOSE))
  		seq_puts(m, ",verbose");
  	if (sbi->s_volume[0])
  		seq_printf(m, ",volume=%s", sbi->s_volume);
  	return 0;
  }
  
  /* This function definitely needs to be split up. Some fine day I'll
   * hopefully have the guts to do so. Until then: sorry for the mess.
   */
  
  static int affs_fill_super(struct super_block *sb, void *data, int silent)
  {
  	struct affs_sb_info	*sbi;
  	struct buffer_head	*root_bh = NULL;
  	struct buffer_head	*boot_bh;
  	struct inode		*root_inode = NULL;
  	s32			 root_block;
  	int			 size, blocksize;
  	u32			 chksum;
  	int			 num_bm;
  	int			 i, j;
  	kuid_t			 uid;
  	kgid_t			 gid;
  	int			 reserved;
  	unsigned long		 mount_flags;
  	int			 tmp_flags;	/* fix remount prototype... */
  	u8			 sig[4];
  	int			 ret;
  
  	pr_debug("read_super(%s)\n", data ? (const char *)data : "no options");
  
  	sb->s_magic             = AFFS_SUPER_MAGIC;
  	sb->s_op                = &affs_sops;
  	sb->s_flags |= SB_NODIRATIME;
  
  	sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL);
  	if (!sbi)
  		return -ENOMEM;
  
  	sb->s_fs_info = sbi;
  	sbi->sb = sb;
  	mutex_init(&sbi->s_bmlock);
  	spin_lock_init(&sbi->symlink_lock);
  	spin_lock_init(&sbi->work_lock);
  	INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
  
  	if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
  				&blocksize,&sbi->s_prefix,
  				sbi->s_volume, &mount_flags)) {
  		pr_err("Error parsing options\n");
  		return -EINVAL;
  	}
  	/* N.B. after this point s_prefix must be released */
  
  	sbi->s_flags   = mount_flags;
  	sbi->s_mode    = i;
  	sbi->s_uid     = uid;
  	sbi->s_gid     = gid;
  	sbi->s_reserved= reserved;
  
  	/* Get the size of the device in 512-byte blocks.
  	 * If we later see that the partition uses bigger
  	 * blocks, we will have to change it.
  	 */
  
  	size = i_size_read(sb->s_bdev->bd_inode) >> 9;
  	pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
  
  	affs_set_blocksize(sb, PAGE_SIZE);
  	/* Try to find root block. Its location depends on the block size. */
  
  	i = bdev_logical_block_size(sb->s_bdev);
  	j = PAGE_SIZE;
  	if (blocksize > 0) {
  		i = j = blocksize;
  		size = size / (blocksize / 512);
  	}
  
  	for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
  		sbi->s_root_block = root_block;
  		if (root_block < 0)
  			sbi->s_root_block = (reserved + size - 1) / 2;
  		pr_debug("setting blocksize to %d\n", blocksize);
  		affs_set_blocksize(sb, blocksize);
  		sbi->s_partition_size = size;
  
  		/* The root block location that was calculated above is not
  		 * correct if the partition size is an odd number of 512-
  		 * byte blocks, which will be rounded down to a number of
  		 * 1024-byte blocks, and if there were an even number of
  		 * reserved blocks. Ideally, all partition checkers should
  		 * report the real number of blocks of the real blocksize,
  		 * but since this just cannot be done, we have to try to
  		 * find the root block anyways. In the above case, it is one
  		 * block behind the calculated one. So we check this one, too.
  		 */
  		for (num_bm = 0; num_bm < 2; num_bm++) {
  			pr_debug("Dev %s, trying root=%u, bs=%d, "
  				"size=%d, reserved=%d\n",
  				sb->s_id,
  				sbi->s_root_block + num_bm,
  				blocksize, size, reserved);
  			root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
  			if (!root_bh)
  				continue;
  			if (!affs_checksum_block(sb, root_bh) &&
  			    be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
  			    be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
  				sbi->s_hashsize    = blocksize / 4 - 56;
  				sbi->s_root_block += num_bm;
  				goto got_root;
  			}
  			affs_brelse(root_bh);
  			root_bh = NULL;
  		}
  	}
  	if (!silent)
  		pr_err("No valid root block on device %s\n", sb->s_id);
  	return -EINVAL;
  
  	/* N.B. after this point bh must be released */
  got_root:
  	/* Keep super block in cache */
  	sbi->s_root_bh = root_bh;
  	root_block = sbi->s_root_block;
  
  	/* Find out which kind of FS we have */
  	boot_bh = sb_bread(sb, 0);
  	if (!boot_bh) {
  		pr_err("Cannot read boot block\n");
  		return -EINVAL;
  	}
  	memcpy(sig, boot_bh->b_data, 4);
  	brelse(boot_bh);
  	chksum = be32_to_cpu(*(__be32 *)sig);
  
  	/* Dircache filesystems are compatible with non-dircache ones
  	 * when reading. As long as they aren't supported, writing is
  	 * not recommended.
  	 */
  	if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
  	     || chksum == MUFS_DCOFS) && !sb_rdonly(sb)) {
  		pr_notice("Dircache FS - mounting %s read only\n", sb->s_id);
  		sb->s_flags |= SB_RDONLY;
  	}
  	switch (chksum) {
  	case MUFS_FS:
  	case MUFS_INTLFFS:
  	case MUFS_DCFFS:
  		affs_set_opt(sbi->s_flags, SF_MUFS);
  		/* fall thru */
  	case FS_INTLFFS:
  	case FS_DCFFS:
  		affs_set_opt(sbi->s_flags, SF_INTL);
  		break;
  	case MUFS_FFS:
  		affs_set_opt(sbi->s_flags, SF_MUFS);
  		break;
  	case FS_FFS:
  		break;
  	case MUFS_OFS:
  		affs_set_opt(sbi->s_flags, SF_MUFS);
  		/* fall thru */
  	case FS_OFS:
  		affs_set_opt(sbi->s_flags, SF_OFS);
  		sb->s_flags |= SB_NOEXEC;
  		break;
  	case MUFS_DCOFS:
  	case MUFS_INTLOFS:
  		affs_set_opt(sbi->s_flags, SF_MUFS);
  	case FS_DCOFS:
  	case FS_INTLOFS:
  		affs_set_opt(sbi->s_flags, SF_INTL);
  		affs_set_opt(sbi->s_flags, SF_OFS);
  		sb->s_flags |= SB_NOEXEC;
  		break;
  	default:
  		pr_err("Unknown filesystem on device %s: %08X\n",
  		       sb->s_id, chksum);
  		return -EINVAL;
  	}
  
  	if (affs_test_opt(mount_flags, SF_VERBOSE)) {
  		u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
  		pr_notice("Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
  			len > 31 ? 31 : len,
  			AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
  			sig, sig[3] + '0', blocksize);
  	}
  
  	sb->s_flags |= SB_NODEV | SB_NOSUID;
  
  	sbi->s_data_blksize = sb->s_blocksize;
  	if (affs_test_opt(sbi->s_flags, SF_OFS))
  		sbi->s_data_blksize -= 24;
  
  	tmp_flags = sb->s_flags;
  	ret = affs_init_bitmap(sb, &tmp_flags);
  	if (ret)
  		return ret;
  	sb->s_flags = tmp_flags;
  
  	/* set up enough so that it can read an inode */
  
  	root_inode = affs_iget(sb, root_block);
  	if (IS_ERR(root_inode))
  		return PTR_ERR(root_inode);
  
  	if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL))
  		sb->s_d_op = &affs_intl_dentry_operations;
  	else
  		sb->s_d_op = &affs_dentry_operations;
  
  	sb->s_root = d_make_root(root_inode);
  	if (!sb->s_root) {
  		pr_err("AFFS: Get root inode failed\n");
  		return -ENOMEM;
  	}
  
  	sb->s_export_op = &affs_export_ops;
  	pr_debug("s_flags=%lX\n", sb->s_flags);
  	return 0;
  }
  
  static int
  affs_remount(struct super_block *sb, int *flags, char *data)
  {
  	struct affs_sb_info	*sbi = AFFS_SB(sb);
  	int			 blocksize;
  	kuid_t			 uid;
  	kgid_t			 gid;
  	int			 mode;
  	int			 reserved;
  	int			 root_block;
  	unsigned long		 mount_flags;
  	int			 res = 0;
  	char			*new_opts;
  	char			 volume[32];
  	char			*prefix = NULL;
  
  	new_opts = kstrdup(data, GFP_KERNEL);
  	if (data && !new_opts)
  		return -ENOMEM;
  
  	pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data);
  
  	sync_filesystem(sb);
  	*flags |= SB_NODIRATIME;
  
  	memcpy(volume, sbi->s_volume, 32);
  	if (!parse_options(data, &uid, &gid, &mode, &reserved, &root_block,
  			   &blocksize, &prefix, volume,
  			   &mount_flags)) {
  		kfree(prefix);
  		kfree(new_opts);
  		return -EINVAL;
  	}
  
  	flush_delayed_work(&sbi->sb_work);
  
  	sbi->s_flags = mount_flags;
  	sbi->s_mode  = mode;
  	sbi->s_uid   = uid;
  	sbi->s_gid   = gid;
  	/* protect against readers */
  	spin_lock(&sbi->symlink_lock);
  	if (prefix) {
  		kfree(sbi->s_prefix);
  		sbi->s_prefix = prefix;
  	}
  	memcpy(sbi->s_volume, volume, 32);
  	spin_unlock(&sbi->symlink_lock);
  
  	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
  		return 0;
  
  	if (*flags & SB_RDONLY)
  		affs_free_bitmap(sb);
  	else
  		res = affs_init_bitmap(sb, flags);
  
  	return res;
  }
  
  static int
  affs_statfs(struct dentry *dentry, struct kstatfs *buf)
  {
  	struct super_block *sb = dentry->d_sb;
  	int		 free;
  	u64		 id = huge_encode_dev(sb->s_bdev->bd_dev);
  
  	pr_debug("%s() partsize=%d, reserved=%d\n",
  		 __func__, AFFS_SB(sb)->s_partition_size,
  		 AFFS_SB(sb)->s_reserved);
  
  	free          = affs_count_free_blocks(sb);
  	buf->f_type    = AFFS_SUPER_MAGIC;
  	buf->f_bsize   = sb->s_blocksize;
  	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
  	buf->f_bfree   = free;
  	buf->f_bavail  = free;
  	buf->f_fsid.val[0] = (u32)id;
  	buf->f_fsid.val[1] = (u32)(id >> 32);
  	buf->f_namelen = AFFSNAMEMAX;
  	return 0;
  }
  
  static struct dentry *affs_mount(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data)
  {
  	return mount_bdev(fs_type, flags, dev_name, data, affs_fill_super);
  }
  
  static void affs_kill_sb(struct super_block *sb)
  {
  	struct affs_sb_info *sbi = AFFS_SB(sb);
  	kill_block_super(sb);
  	if (sbi) {
  		affs_free_bitmap(sb);
  		affs_brelse(sbi->s_root_bh);
  		kfree(sbi->s_prefix);
  		mutex_destroy(&sbi->s_bmlock);
  		kfree(sbi);
  	}
  }
  
  static struct file_system_type affs_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "affs",
  	.mount		= affs_mount,
  	.kill_sb	= affs_kill_sb,
  	.fs_flags	= FS_REQUIRES_DEV,
  };
  MODULE_ALIAS_FS("affs");
  
  static int __init init_affs_fs(void)
  {
  	int err = init_inodecache();
  	if (err)
  		goto out1;
  	err = register_filesystem(&affs_fs_type);
  	if (err)
  		goto out;
  	return 0;
  out:
  	destroy_inodecache();
  out1:
  	return err;
  }
  
  static void __exit exit_affs_fs(void)
  {
  	unregister_filesystem(&affs_fs_type);
  	destroy_inodecache();
  }
  
  MODULE_DESCRIPTION("Amiga filesystem support for Linux");
  MODULE_LICENSE("GPL");
  
  module_init(init_affs_fs)
  module_exit(exit_affs_fs)
  