/*
   *  linux/fs/affs/namei.c
   *
   *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   *
   *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
   *
   *  (C) 1991  Linus Torvalds - minix filesystem
   */
  
  #include "affs.h"
  
  typedef int (*toupper_t)(int);
  
  static int	 affs_toupper(int ch);

  static int	 affs_hash_dentry(const struct dentry *, struct qstr *);
  static int       affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,

  		unsigned int len, const char *str, const struct qstr *name);

  static int	 affs_intl_toupper(int ch);

  static int	 affs_intl_hash_dentry(const struct dentry *, struct qstr *);
  static int       affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,

  		unsigned int len, const char *str, const struct qstr *name);

  const struct dentry_operations affs_dentry_operations = {

  	.d_hash		= affs_hash_dentry,
  	.d_compare	= affs_compare_dentry,
  };

  const struct dentry_operations affs_intl_dentry_operations = {

  	.d_hash		= affs_intl_hash_dentry,
  	.d_compare	= affs_intl_compare_dentry,
  };
  
  
  /* Simple toupper() for DOS\1 */
  
  static int
  affs_toupper(int ch)
  {
  	return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
  }
  
  /* International toupper() for DOS\3 ("international") */
  
  static int
  affs_intl_toupper(int ch)
  {
  	return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
  		&& ch <= 0xFE && ch != 0xF7) ?
  		ch - ('a' - 'A') : ch;
  }
  
  static inline toupper_t
  affs_get_toupper(struct super_block *sb)
  {
  	return AFFS_SB(sb)->s_flags & SF_INTL ? affs_intl_toupper : affs_toupper;
  }
  
  /*
   * Note: the dentry argument is the parent dentry.
   */
  static inline int

  __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)

  {
  	const u8 *name = qstr->name;
  	unsigned long hash;
  	int i;

  	i = affs_check_name(qstr->name, qstr->len, notruncate);

  	if (i)
  		return i;
  
  	hash = init_name_hash();
  	i = min(qstr->len, 30u);
  	for (; i > 0; name++, i--)
  		hash = partial_name_hash(toupper(*name), hash);
  	qstr->hash = end_name_hash(hash);
  
  	return 0;
  }
  
  static int

  affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)

  {

  	return __affs_hash_dentry(qstr, affs_toupper,
  				  affs_nofilenametruncate(dentry));

  }

  static int

  affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)

  {

  	return __affs_hash_dentry(qstr, affs_intl_toupper,
  				  affs_nofilenametruncate(dentry));

  }

  static inline int __affs_compare_dentry(unsigned int len,

  		const char *str, const struct qstr *name, toupper_t toupper,
  		bool notruncate)

  {

  	const u8 *aname = str;
  	const u8 *bname = name->name;

  	/*
  	 * 'str' is the name of an already existing dentry, so the name
  	 * must be valid. 'name' must be validated first.

  	 */

  	if (affs_check_name(name->name, name->len, notruncate))

  		return 1;

  	/*
  	 * If the names are longer than the allowed 30 chars,

  	 * the excess is ignored, so their length may differ.
  	 */

  	if (len >= 30) {

  		if (name->len < 30)

  			return 1;
  		len = 30;

  	} else if (len != name->len)

  		return 1;
  
  	for (; len > 0; len--)
  		if (toupper(*aname++) != toupper(*bname++))
  			return 1;
  
  	return 0;
  }
  
  static int

  affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,

  		unsigned int len, const char *str, const struct qstr *name)

  {

  
  	return __affs_compare_dentry(len, str, name, affs_toupper,
  				     affs_nofilenametruncate(parent));

  }

  static int

  affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,

  		unsigned int len, const char *str, const struct qstr *name)

  {

  	return __affs_compare_dentry(len, str, name, affs_intl_toupper,
  				     affs_nofilenametruncate(parent));

  }
  
  /*
   * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
   */
  
  static inline int
  affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
  {
  	const u8 *name = dentry->d_name.name;
  	int len = dentry->d_name.len;
  
  	if (len >= 30) {
  		if (*name2 < 30)
  			return 0;
  		len = 30;
  	} else if (len != *name2)
  		return 0;
  
  	for (name2++; len > 0; len--)
  		if (toupper(*name++) != toupper(*name2++))
  			return 0;
  	return 1;
  }
  
  int
  affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
  {
  	toupper_t toupper = affs_get_toupper(sb);
  	int hash;
  
  	hash = len = min(len, 30u);
  	for (; len > 0; len--)
  		hash = (hash * 13 + toupper(*name++)) & 0x7ff;
  
  	return hash % AFFS_SB(sb)->s_hashsize;
  }
  
  static struct buffer_head *
  affs_find_entry(struct inode *dir, struct dentry *dentry)
  {
  	struct super_block *sb = dir->i_sb;
  	struct buffer_head *bh;
  	toupper_t toupper = affs_get_toupper(sb);
  	u32 key;
  
  	pr_debug("AFFS: find_entry(\"%.*s\")
  ", (int)dentry->d_name.len, dentry->d_name.name);
  
  	bh = affs_bread(sb, dir->i_ino);
  	if (!bh)
  		return ERR_PTR(-EIO);
  
  	key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
  
  	for (;;) {
  		affs_brelse(bh);
  		if (key == 0)
  			return NULL;
  		bh = affs_bread(sb, key);
  		if (!bh)
  			return ERR_PTR(-EIO);
  		if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
  			return bh;
  		key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
  	}
  }
  
  struct dentry *

  affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)

  {
  	struct super_block *sb = dir->i_sb;
  	struct buffer_head *bh;
  	struct inode *inode = NULL;
  
  	pr_debug("AFFS: lookup(\"%.*s\")
  ",(int)dentry->d_name.len,dentry->d_name.name);
  
  	affs_lock_dir(dir);
  	bh = affs_find_entry(dir, dentry);
  	affs_unlock_dir(dir);

  	if (IS_ERR(bh))

  		return ERR_CAST(bh);

  	if (bh) {
  		u32 ino = bh->b_blocknr;
  
  		/* store the real header ino in d_fsdata for faster lookups */
  		dentry->d_fsdata = (void *)(long)ino;
  		switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
  		//link to dirs disabled
  		//case ST_LINKDIR:
  		case ST_LINKFILE:
  			ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
  		}
  		affs_brelse(bh);

  		inode = affs_iget(sb, ino);
  		if (IS_ERR(inode))

  			return ERR_CAST(inode);

  	}

  	d_add(dentry, inode);
  	return NULL;
  }
  
  int
  affs_unlink(struct inode *dir, struct dentry *dentry)
  {

  	pr_debug("AFFS: unlink(dir=%d, %lu \"%.*s\")
  ", (u32)dir->i_ino,
  		 dentry->d_inode->i_ino,

  		 (int)dentry->d_name.len, dentry->d_name.name);
  
  	return affs_remove_header(dentry);
  }
  
  int

  affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)

  {
  	struct super_block *sb = dir->i_sb;
  	struct inode	*inode;
  	int		 error;

  	pr_debug("AFFS: create(%lu,\"%.*s\",0%ho)
  ",dir->i_ino,(int)dentry->d_name.len,

  		 dentry->d_name.name,mode);
  
  	inode = affs_new_inode(dir);
  	if (!inode)
  		return -ENOSPC;
  
  	inode->i_mode = mode;
  	mode_to_prot(inode);
  	mark_inode_dirty(inode);
  
  	inode->i_op = &affs_file_inode_operations;
  	inode->i_fop = &affs_file_operations;
  	inode->i_mapping->a_ops = (AFFS_SB(sb)->s_flags & SF_OFS) ? &affs_aops_ofs : &affs_aops;
  	error = affs_add_entry(dir, inode, dentry, ST_FILE);
  	if (error) {

  		clear_nlink(inode);

  		iput(inode);
  		return error;
  	}
  	return 0;
  }
  
  int

  affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)

  {
  	struct inode		*inode;
  	int			 error;

  	pr_debug("AFFS: mkdir(%lu,\"%.*s\",0%ho)
  ",dir->i_ino,

  		 (int)dentry->d_name.len,dentry->d_name.name,mode);
  
  	inode = affs_new_inode(dir);
  	if (!inode)
  		return -ENOSPC;
  
  	inode->i_mode = S_IFDIR | mode;
  	mode_to_prot(inode);
  
  	inode->i_op = &affs_dir_inode_operations;
  	inode->i_fop = &affs_dir_operations;
  
  	error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
  	if (error) {

  		clear_nlink(inode);

  		mark_inode_dirty(inode);
  		iput(inode);
  		return error;
  	}
  	return 0;
  }
  
  int
  affs_rmdir(struct inode *dir, struct dentry *dentry)
  {

  	pr_debug("AFFS: rmdir(dir=%u, %lu \"%.*s\")
  ", (u32)dir->i_ino,
  		 dentry->d_inode->i_ino,

  		 (int)dentry->d_name.len, dentry->d_name.name);
  
  	return affs_remove_header(dentry);
  }
  
  int
  affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
  {
  	struct super_block	*sb = dir->i_sb;
  	struct buffer_head	*bh;
  	struct inode		*inode;
  	char			*p;
  	int			 i, maxlen, error;
  	char			 c, lc;
  
  	pr_debug("AFFS: symlink(%lu,\"%.*s\" -> \"%s\")
  ",dir->i_ino,
  		 (int)dentry->d_name.len,dentry->d_name.name,symname);
  
  	maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
  	inode  = affs_new_inode(dir);
  	if (!inode)
  		return -ENOSPC;
  
  	inode->i_op = &affs_symlink_inode_operations;
  	inode->i_data.a_ops = &affs_symlink_aops;
  	inode->i_mode = S_IFLNK | 0777;
  	mode_to_prot(inode);
  
  	error = -EIO;
  	bh = affs_bread(sb, inode->i_ino);
  	if (!bh)
  		goto err;
  	i  = 0;
  	p  = (char *)AFFS_HEAD(bh)->table;
  	lc = '/';
  	if (*symname == '/') {

  		struct affs_sb_info *sbi = AFFS_SB(sb);

  		while (*symname == '/')
  			symname++;

  		spin_lock(&sbi->symlink_lock);
  		while (sbi->s_volume[i])	/* Cannot overflow */
  			*p++ = sbi->s_volume[i++];
  		spin_unlock(&sbi->symlink_lock);

  	}
  	while (i < maxlen && (c = *symname++)) {
  		if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
  			*p++ = '/';
  			i++;
  			symname += 2;
  			lc = '/';
  		} else if (c == '.' && lc == '/' && *symname == '/') {
  			symname++;
  			lc = '/';
  		} else {
  			*p++ = c;
  			lc   = c;
  			i++;
  		}
  		if (lc == '/')
  			while (*symname == '/')
  				symname++;
  	}
  	*p = 0;
  	mark_buffer_dirty_inode(bh, inode);
  	affs_brelse(bh);
  	mark_inode_dirty(inode);
  
  	error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
  	if (error)
  		goto err;
  
  	return 0;
  
  err:

  	clear_nlink(inode);

  	mark_inode_dirty(inode);
  	iput(inode);
  	return error;
  }
  
  int
  affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
  {
  	struct inode *inode = old_dentry->d_inode;
  
  	pr_debug("AFFS: link(%u, %u, \"%.*s\")
  ", (u32)inode->i_ino, (u32)dir->i_ino,
  		 (int)dentry->d_name.len,dentry->d_name.name);
  
  	return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
  }
  
  int
  affs_rename(struct inode *old_dir, struct dentry *old_dentry,
  	    struct inode *new_dir, struct dentry *new_dentry)
  {
  	struct super_block *sb = old_dir->i_sb;
  	struct buffer_head *bh = NULL;
  	int retval;
  
  	pr_debug("AFFS: rename(old=%u,\"%*s\" to new=%u,\"%*s\")
  ",
  		 (u32)old_dir->i_ino, (int)old_dentry->d_name.len, old_dentry->d_name.name,
  		 (u32)new_dir->i_ino, (int)new_dentry->d_name.len, new_dentry->d_name.name);

  	retval = affs_check_name(new_dentry->d_name.name,
  				 new_dentry->d_name.len,
  				 affs_nofilenametruncate(old_dentry));

  	if (retval)
  		return retval;
  
  	/* Unlink destination if it already exists */
  	if (new_dentry->d_inode) {
  		retval = affs_remove_header(new_dentry);
  		if (retval)
  			return retval;
  	}

  	bh = affs_bread(sb, old_dentry->d_inode->i_ino);
  	if (!bh)

  		return -EIO;

  
  	/* Remove header from its parent directory. */
  	affs_lock_dir(old_dir);
  	retval = affs_remove_hash(old_dir, bh);
  	affs_unlock_dir(old_dir);
  	if (retval)
  		goto done;
  
  	/* And insert it into the new directory with the new name. */
  	affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
  	affs_fix_checksum(sb, bh);
  	affs_lock_dir(new_dir);
  	retval = affs_insert_hash(new_dir, bh);
  	affs_unlock_dir(new_dir);
  	/* TODO: move it back to old_dir, if error? */
  
  done:
  	mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
  	affs_brelse(bh);
  	return retval;
  }