/*
   *  linux/fs/adfs/dir_fplus.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/buffer_head.h>

  #include <linux/slab.h>

  #include "adfs.h"
  #include "dir_fplus.h"
  
  static int
  adfs_fplus_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir)
  {
  	struct adfs_bigdirheader *h;
  	struct adfs_bigdirtail *t;
  	unsigned long block;
  	unsigned int blk, size;
  	int i, ret = -EIO;
  
  	dir->nr_buffers = 0;

  	/* start off using fixed bh set - only alloc for big dirs */
  	dir->bh_fplus = &dir->bh[0];

  	block = __adfs_block_map(sb, id, 0);
  	if (!block) {
  		adfs_error(sb, "dir object %X has a hole at offset 0", id);
  		goto out;
  	}

  	dir->bh_fplus[0] = sb_bread(sb, block);
  	if (!dir->bh_fplus[0])

  		goto out;
  	dir->nr_buffers += 1;

  	h = (struct adfs_bigdirheader *)dir->bh_fplus[0]->b_data;

  	size = le32_to_cpu(h->bigdirsize);
  	if (size != sz) {

  		printk(KERN_WARNING "adfs: adfs_fplus_read:"
  					" directory header size %X
  "
  					" does not match directory size %X
  ",
  					size, sz);

  	}
  
  	if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 ||
  	    h->bigdirversion[2] != 0 || size & 2047 ||

  	    h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME)) {
  		printk(KERN_WARNING "adfs: dir object %X has"
  					" malformed dir header
  ", id);

  		goto out;

  	}

  
  	size >>= sb->s_blocksize_bits;

  	if (size > sizeof(dir->bh)/sizeof(dir->bh[0])) {
  		/* this directory is too big for fixed bh set, must allocate */
  		struct buffer_head **bh_fplus =
  			kzalloc(size * sizeof(struct buffer_head *),
  				GFP_KERNEL);
  		if (!bh_fplus) {
  			adfs_error(sb, "not enough memory for"
  					" dir object %X (%d blocks)", id, size);
  			goto out;
  		}
  		dir->bh_fplus = bh_fplus;
  		/* copy over the pointer to the block that we've already read */
  		dir->bh_fplus[0] = dir->bh[0];
  	}

  	for (blk = 1; blk < size; blk++) {
  		block = __adfs_block_map(sb, id, blk);
  		if (!block) {
  			adfs_error(sb, "dir object %X has a hole at offset %d", id, blk);
  			goto out;
  		}

  		dir->bh_fplus[blk] = sb_bread(sb, block);
  		if (!dir->bh_fplus[blk]) {
  			adfs_error(sb,	"dir object %X failed read for"
  					" offset %d, mapped block %X",
  					id, blk, block);

  			goto out;

  		}
  
  		dir->nr_buffers += 1;

  	}

  	t = (struct adfs_bigdirtail *)
  		(dir->bh_fplus[size - 1]->b_data + (sb->s_blocksize - 8));

  
  	if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) ||
  	    t->bigdirendmasseq != h->startmasseq ||

  	    t->reserved[0] != 0 || t->reserved[1] != 0) {
  		printk(KERN_WARNING "adfs: dir object %X has "
  					"malformed dir end
  ", id);

  		goto out;

  	}

  
  	dir->parent_id = le32_to_cpu(h->bigdirparent);
  	dir->sb = sb;
  	return 0;

  out:

  	if (dir->bh_fplus) {
  		for (i = 0; i < dir->nr_buffers; i++)
  			brelse(dir->bh_fplus[i]);
  
  		if (&dir->bh[0] != dir->bh_fplus)
  			kfree(dir->bh_fplus);
  
  		dir->bh_fplus = NULL;
  	}
  
  	dir->nr_buffers = 0;

  	dir->sb = NULL;
  	return ret;
  }
  
  static int
  adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos)
  {

  	struct adfs_bigdirheader *h =
  		(struct adfs_bigdirheader *) dir->bh_fplus[0]->b_data;

  	int ret = -ENOENT;
  
  	if (fpos <= le32_to_cpu(h->bigdirentries)) {
  		dir->pos = fpos;
  		ret = 0;
  	}
  
  	return ret;
  }
  
  static void
  dir_memcpy(struct adfs_dir *dir, unsigned int offset, void *to, int len)
  {
  	struct super_block *sb = dir->sb;
  	unsigned int buffer, partial, remainder;
  
  	buffer = offset >> sb->s_blocksize_bits;
  	offset &= sb->s_blocksize - 1;
  
  	partial = sb->s_blocksize - offset;
  
  	if (partial >= len)

  		memcpy(to, dir->bh_fplus[buffer]->b_data + offset, len);

  	else {
  		char *c = (char *)to;
  
  		remainder = len - partial;

  		memcpy(c,
  			dir->bh_fplus[buffer]->b_data + offset,
  			partial);
  
  		memcpy(c + partial,
  			dir->bh_fplus[buffer + 1]->b_data,
  			remainder);

  	}
  }
  
  static int
  adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
  {

  	struct adfs_bigdirheader *h =
  		(struct adfs_bigdirheader *) dir->bh_fplus[0]->b_data;

  	struct adfs_bigdirentry bde;
  	unsigned int offset;
  	int i, ret = -ENOENT;
  
  	if (dir->pos >= le32_to_cpu(h->bigdirentries))
  		goto out;
  
  	offset = offsetof(struct adfs_bigdirheader, bigdirname);
  	offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
  	offset += dir->pos * sizeof(struct adfs_bigdirentry);
  
  	dir_memcpy(dir, offset, &bde, sizeof(struct adfs_bigdirentry));
  
  	obj->loadaddr = le32_to_cpu(bde.bigdirload);
  	obj->execaddr = le32_to_cpu(bde.bigdirexec);
  	obj->size     = le32_to_cpu(bde.bigdirlen);
  	obj->file_id  = le32_to_cpu(bde.bigdirindaddr);
  	obj->attr     = le32_to_cpu(bde.bigdirattr);
  	obj->name_len = le32_to_cpu(bde.bigdirobnamelen);
  
  	offset = offsetof(struct adfs_bigdirheader, bigdirname);
  	offset += ((le32_to_cpu(h->bigdirnamelen) + 4) & ~3);
  	offset += le32_to_cpu(h->bigdirentries) * sizeof(struct adfs_bigdirentry);
  	offset += le32_to_cpu(bde.bigdirobnameptr);
  
  	dir_memcpy(dir, offset, obj->name, obj->name_len);
  	for (i = 0; i < obj->name_len; i++)
  		if (obj->name[i] == '/')
  			obj->name[i] = '.';

  	obj->filetype = -1;
  
  	/*
  	 * object is a file and is filetyped and timestamped?
  	 * RISC OS 12-bit filetype is stored in load_address[19:8]
  	 */
  	if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
  		(0xfff00000 == (0xfff00000 & obj->loadaddr))) {
  		obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);
  
  		/* optionally append the ,xyz hex filetype suffix */
  		if (ADFS_SB(dir->sb)->s_ftsuffix)
  			obj->name_len +=
  				append_filetype_suffix(
  					&obj->name[obj->name_len],
  					obj->filetype);
  	}

  	dir->pos += 1;
  	ret = 0;
  out:
  	return ret;
  }

  static int
  adfs_fplus_sync(struct adfs_dir *dir)
  {
  	int err = 0;
  	int i;
  
  	for (i = dir->nr_buffers - 1; i >= 0; i--) {

  		struct buffer_head *bh = dir->bh_fplus[i];

  		sync_dirty_buffer(bh);
  		if (buffer_req(bh) && !buffer_uptodate(bh))
  			err = -EIO;
  	}
  
  	return err;
  }

  static void
  adfs_fplus_free(struct adfs_dir *dir)
  {
  	int i;

  	if (dir->bh_fplus) {
  		for (i = 0; i < dir->nr_buffers; i++)
  			brelse(dir->bh_fplus[i]);
  
  		if (&dir->bh[0] != dir->bh_fplus)
  			kfree(dir->bh_fplus);
  
  		dir->bh_fplus = NULL;
  	}
  
  	dir->nr_buffers = 0;

  	dir->sb = NULL;
  }
  
  struct adfs_dir_ops adfs_fplus_dir_ops = {
  	.read		= adfs_fplus_read,
  	.setpos		= adfs_fplus_setpos,
  	.getnext	= adfs_fplus_getnext,

  	.sync		= adfs_fplus_sync,

  	.free		= adfs_fplus_free
  };