text: // SPDX-License-Identifier: GPL-2.0
  /*
   *  linux/fs/affs/amigaffs.c
   *
   *  (c) 1996  Hans-Joachim Widmaier - Rewritten
   *
   *  (C) 1993  Ray Burr - Amiga FFS filesystem.
   *
   *  Please send bug reports to: hjw@zvw.de
   */
  
  #include <linux/math64.h>
  #include "affs.h"
  
  /*
   * Functions for accessing Amiga-FFS structures.
   */
  
  
  /* Insert a header block bh into the directory dir
   * caller must hold AFFS_DIR->i_hash_lock!
   */
  
  int
  affs_insert_hash(struct inode *dir, struct buffer_head *bh)
  {
  	struct super_block *sb = dir->i_sb;
  	struct buffer_head *dir_bh;
  	u32 ino, hash_ino;
  	int offset;
  
  	ino = bh->b_blocknr;
  	offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
  
  	pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
  
  	dir_bh = affs_bread(sb, dir->i_ino);
  	if (!dir_bh)
  		return -EIO;
  
  	hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
  	while (hash_ino) {
  		affs_brelse(dir_bh);
  		dir_bh = affs_bread(sb, hash_ino);
  		if (!dir_bh)
  			return -EIO;
  		hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
  	}
  	AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
  	AFFS_TAIL(sb, bh)->hash_chain = 0;
  	affs_fix_checksum(sb, bh);
  
  	if (dir->i_ino == dir_bh->b_blocknr)
  		AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
  	else
  		AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
  
  	affs_adjust_checksum(dir_bh, ino);
  	mark_buffer_dirty_inode(dir_bh, dir);
  	affs_brelse(dir_bh);
  
  	dir->i_mtime = dir->i_ctime = current_time(dir);
  	dir->i_version++;
  	mark_inode_dirty(dir);
  
  	return 0;
  }
  
  /* Remove a header block from its directory.
   * caller must hold AFFS_DIR->i_hash_lock!
   */
  
  int
  affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
  {
  	struct super_block *sb;
  	struct buffer_head *bh;
  	u32 rem_ino, hash_ino;
  	__be32 ino;
  	int offset, retval;
  
  	sb = dir->i_sb;
  	rem_ino = rem_bh->b_blocknr;
  	offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
  	pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
  		 rem_ino, offset);
  
  	bh = affs_bread(sb, dir->i_ino);
  	if (!bh)
  		return -EIO;
  
  	retval = -ENOENT;
  	hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
  	while (hash_ino) {
  		if (hash_ino == rem_ino) {
  			ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
  			if (dir->i_ino == bh->b_blocknr)
  				AFFS_HEAD(bh)->table[offset] = ino;
  			else
  				AFFS_TAIL(sb, bh)->hash_chain = ino;
  			affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
  			mark_buffer_dirty_inode(bh, dir);
  			AFFS_TAIL(sb, rem_bh)->parent = 0;
  			retval = 0;
  			break;
  		}
  		affs_brelse(bh);
  		bh = affs_bread(sb, hash_ino);
  		if (!bh)
  			return -EIO;
  		hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
  	}
  
  	affs_brelse(bh);
  
  	dir->i_mtime = dir->i_ctime = current_time(dir);
  	dir->i_version++;
  	mark_inode_dirty(dir);
  
  	return retval;
  }
  
  static void
  affs_fix_dcache(struct inode *inode, u32 entry_ino)
  {
  	struct dentry *dentry;
  	spin_lock(&inode->i_lock);
  	hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
  		if (entry_ino == (u32)(long)dentry->d_fsdata) {
  			dentry->d_fsdata = (void *)inode->i_ino;
  			break;
  		}
  	}
  	spin_unlock(&inode->i_lock);
  }
  
  
  /* Remove header from link chain */
  
  static int
  affs_remove_link(struct dentry *dentry)
  {
  	struct inode *dir, *inode = d_inode(dentry);
  	struct super_block *sb = inode->i_sb;
  	struct buffer_head *bh, *link_bh = NULL;
  	u32 link_ino, ino;
  	int retval;
  
  	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
  	retval = -EIO;
  	bh = affs_bread(sb, inode->i_ino);
  	if (!bh)
  		goto done;
  
  	link_ino = (u32)(long)dentry->d_fsdata;
  	if (inode->i_ino == link_ino) {
  		/* we can't remove the head of the link, as its blocknr is still used as ino,
  		 * so we remove the block of the first link instead.
  		 */ 
  		link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
  		link_bh = affs_bread(sb, link_ino);
  		if (!link_bh)
  			goto done;
  
  		dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
  		if (IS_ERR(dir)) {
  			retval = PTR_ERR(dir);
  			goto done;
  		}
  
  		affs_lock_dir(dir);
  		/*
  		 * if there's a dentry for that block, make it
  		 * refer to inode itself.
  		 */
  		affs_fix_dcache(inode, link_ino);
  		retval = affs_remove_hash(dir, link_bh);
  		if (retval) {
  			affs_unlock_dir(dir);
  			goto done;
  		}
  		mark_buffer_dirty_inode(link_bh, inode);
  
  		memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
  		retval = affs_insert_hash(dir, bh);
  		if (retval) {
  			affs_unlock_dir(dir);
  			goto done;
  		}
  		mark_buffer_dirty_inode(bh, inode);
  
  		affs_unlock_dir(dir);
  		iput(dir);
  	} else {
  		link_bh = affs_bread(sb, link_ino);
  		if (!link_bh)
  			goto done;
  	}
  
  	while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
  		if (ino == link_ino) {
  			__be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
  			AFFS_TAIL(sb, bh)->link_chain = ino2;
  			affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
  			mark_buffer_dirty_inode(bh, inode);
  			retval = 0;
  			/* Fix the link count, if bh is a normal header block without links */
  			switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
  			case ST_LINKDIR:
  			case ST_LINKFILE:
  				break;
  			default:
  				if (!AFFS_TAIL(sb, bh)->link_chain)
  					set_nlink(inode, 1);
  			}
  			affs_free_block(sb, link_ino);
  			goto done;
  		}
  		affs_brelse(bh);
  		bh = affs_bread(sb, ino);
  		if (!bh)
  			goto done;
  	}
  	retval = -ENOENT;
  done:
  	affs_brelse(link_bh);
  	affs_brelse(bh);
  	return retval;
  }
  
  
  static int
  affs_empty_dir(struct inode *inode)
  {
  	struct super_block *sb = inode->i_sb;
  	struct buffer_head *bh;
  	int retval, size;
  
  	retval = -EIO;
  	bh = affs_bread(sb, inode->i_ino);
  	if (!bh)
  		goto done;
  
  	retval = -ENOTEMPTY;
  	for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
  		if (AFFS_HEAD(bh)->table[size])
  			goto not_empty;
  	retval = 0;
  not_empty:
  	affs_brelse(bh);
  done:
  	return retval;
  }
  
  
  /* Remove a filesystem object. If the object to be removed has
   * links to it, one of the links must be changed to inherit
   * the file or directory. As above, any inode will do.
   * The buffer will not be freed. If the header is a link, the
   * block will be marked as free.
   * This function returns a negative error number in case of
   * an error, else 0 if the inode is to be deleted or 1 if not.
   */
  
  int
  affs_remove_header(struct dentry *dentry)
  {
  	struct super_block *sb;
  	struct inode *inode, *dir;
  	struct buffer_head *bh = NULL;
  	int retval;
  
  	dir = d_inode(dentry->d_parent);
  	sb = dir->i_sb;
  
  	retval = -ENOENT;
  	inode = d_inode(dentry);
  	if (!inode)
  		goto done;
  
  	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
  	retval = -EIO;
  	bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
  	if (!bh)
  		goto done;
  
  	affs_lock_link(inode);
  	affs_lock_dir(dir);
  	switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
  	case ST_USERDIR:
  		/* if we ever want to support links to dirs
  		 * i_hash_lock of the inode must only be
  		 * taken after some checks
  		 */
  		affs_lock_dir(inode);
  		retval = affs_empty_dir(inode);
  		affs_unlock_dir(inode);
  		if (retval)
  			goto done_unlock;
  		break;
  	default:
  		break;
  	}
  
  	retval = affs_remove_hash(dir, bh);
  	if (retval)
  		goto done_unlock;
  	mark_buffer_dirty_inode(bh, inode);
  
  	affs_unlock_dir(dir);
  
  	if (inode->i_nlink > 1)
  		retval = affs_remove_link(dentry);
  	else
  		clear_nlink(inode);
  	affs_unlock_link(inode);
  	inode->i_ctime = current_time(inode);
  	mark_inode_dirty(inode);
  
  done:
  	affs_brelse(bh);
  	return retval;
  
  done_unlock:
  	affs_unlock_dir(dir);
  	affs_unlock_link(inode);
  	goto done;
  }
  
  /* Checksum a block, do various consistency checks and optionally return
     the blocks type number.  DATA points to the block.  If their pointers
     are non-null, *PTYPE and *STYPE are set to the primary and secondary
     block types respectively, *HASHSIZE is set to the size of the hashtable
     (which lets us calculate the block size).
     Returns non-zero if the block is not consistent. */
  
  u32
  affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
  {
  	__be32 *ptr = (__be32 *)bh->b_data;
  	u32 sum;
  	int bsize;
  
  	sum = 0;
  	for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
  		sum += be32_to_cpu(*ptr++);
  	return sum;
  }
  
  /*
   * Calculate the checksum of a disk block and store it
   * at the indicated position.
   */
  
  void
  affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
  {
  	int cnt = sb->s_blocksize / sizeof(__be32);
  	__be32 *ptr = (__be32 *)bh->b_data;
  	u32 checksum;
  	__be32 *checksumptr;
  
  	checksumptr = ptr + 5;
  	*checksumptr = 0;
  	for (checksum = 0; cnt > 0; ptr++, cnt--)
  		checksum += be32_to_cpu(*ptr);
  	*checksumptr = cpu_to_be32(-checksum);
  }
  
  void
  affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
  {
  	u32	 days;
  	u32	 minute;
  	s32	 rem;
  
  	secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
  	if (secs < 0)
  		secs = 0;
  	days    = div_s64_rem(secs, 86400, &rem);
  	minute  = rem / 60;
  	rem    -= minute * 60;
  
  	ds->days = cpu_to_be32(days);
  	ds->mins = cpu_to_be32(minute);
  	ds->ticks = cpu_to_be32(rem * 50);
  }
  
  umode_t
  affs_prot_to_mode(u32 prot)
  {
  	umode_t mode = 0;
  
  	if (!(prot & FIBF_NOWRITE))
  		mode |= 0200;
  	if (!(prot & FIBF_NOREAD))
  		mode |= 0400;
  	if (!(prot & FIBF_NOEXECUTE))
  		mode |= 0100;
  	if (prot & FIBF_GRP_WRITE)
  		mode |= 0020;
  	if (prot & FIBF_GRP_READ)
  		mode |= 0040;
  	if (prot & FIBF_GRP_EXECUTE)
  		mode |= 0010;
  	if (prot & FIBF_OTR_WRITE)
  		mode |= 0002;
  	if (prot & FIBF_OTR_READ)
  		mode |= 0004;
  	if (prot & FIBF_OTR_EXECUTE)
  		mode |= 0001;
  
  	return mode;
  }
  
  void
  affs_mode_to_prot(struct inode *inode)
  {
  	u32 prot = AFFS_I(inode)->i_protect;
  	umode_t mode = inode->i_mode;
  
  	if (!(mode & 0100))
  		prot |= FIBF_NOEXECUTE;
  	if (!(mode & 0400))
  		prot |= FIBF_NOREAD;
  	if (!(mode & 0200))
  		prot |= FIBF_NOWRITE;
  	if (mode & 0010)
  		prot |= FIBF_GRP_EXECUTE;
  	if (mode & 0040)
  		prot |= FIBF_GRP_READ;
  	if (mode & 0020)
  		prot |= FIBF_GRP_WRITE;
  	if (mode & 0001)
  		prot |= FIBF_OTR_EXECUTE;
  	if (mode & 0004)
  		prot |= FIBF_OTR_READ;
  	if (mode & 0002)
  		prot |= FIBF_OTR_WRITE;
  
  	AFFS_I(inode)->i_protect = prot;
  }
  
  void
  affs_error(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_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
  	if (!sb_rdonly(sb))
  		pr_warn("Remounting filesystem read-only\n");
  	sb->s_flags |= SB_RDONLY;
  	va_end(args);
  }
  
  void
  affs_warning(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("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
  	va_end(args);
  }
  
  bool
  affs_nofilenametruncate(const struct dentry *dentry)
  {
  	return affs_test_opt(AFFS_SB(dentry->d_sb)->s_flags, SF_NO_TRUNCATE);
  }
  
  /* Check if the name is valid for a affs object. */
  
  int
  affs_check_name(const unsigned char *name, int len, bool notruncate)
  {
  	int	 i;
  
  	if (len > AFFSNAMEMAX) {
  		if (notruncate)
  			return -ENAMETOOLONG;
  		len = AFFSNAMEMAX;
  	}
  	for (i = 0; i < len; i++) {
  		if (name[i] < ' ' || name[i] == ':'
  		    || (name[i] > 0x7e && name[i] < 0xa0))
  			return -EINVAL;
  	}
  
  	return 0;
  }
  
  /* This function copies name to bstr, with at most 30
   * characters length. The bstr will be prepended by
   * a length byte.
   * NOTE: The name will must be already checked by
   *       affs_check_name()!
   */
  
  int
  affs_copy_name(unsigned char *bstr, struct dentry *dentry)
  {
  	u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
  
  	*bstr++ = len;
  	memcpy(bstr, dentry->d_name.name, len);
  	return len;
  }
  