/*
   *  linux/fs/ufs/util.c
   *
   * Copyright (C) 1998
   * Daniel Pirkl <daniel.pirkl@email.cz>
   * Charles University, Faculty of Mathematics and Physics
   */
   
  #include <linux/string.h>
  #include <linux/slab.h>
  #include <linux/buffer_head.h>
  
  #include "ufs_fs.h"
  #include "ufs.h"
  #include "swab.h"
  #include "util.h"
  
  struct ufs_buffer_head * _ubh_bread_ (struct ufs_sb_private_info * uspi,
  	struct super_block *sb, u64 fragment, u64 size)
  {
  	struct ufs_buffer_head * ubh;
  	unsigned i, j ;
  	u64  count = 0;
  	if (size & ~uspi->s_fmask)
  		return NULL;
  	count = size >> uspi->s_fshift;
  	if (count > UFS_MAXFRAG)
  		return NULL;
  	ubh = kmalloc (sizeof (struct ufs_buffer_head), GFP_NOFS);
  	if (!ubh)
  		return NULL;
  	ubh->fragment = fragment;
  	ubh->count = count;
  	for (i = 0; i < count; i++)
  		if (!(ubh->bh[i] = sb_bread(sb, fragment + i)))
  			goto failed;
  	for (; i < UFS_MAXFRAG; i++)
  		ubh->bh[i] = NULL;
  	return ubh;
  failed:
  	for (j = 0; j < i; j++)
  		brelse (ubh->bh[j]);
  	kfree(ubh);
  	return NULL;
  }
  
  struct ufs_buffer_head * ubh_bread_uspi (struct ufs_sb_private_info * uspi,
  	struct super_block *sb, u64 fragment, u64 size)
  {
  	unsigned i, j;
  	u64 count = 0;
  	if (size & ~uspi->s_fmask)
  		return NULL;
  	count = size >> uspi->s_fshift;
  	if (count <= 0 || count > UFS_MAXFRAG)
  		return NULL;
  	USPI_UBH(uspi)->fragment = fragment;
  	USPI_UBH(uspi)->count = count;
  	for (i = 0; i < count; i++)
  		if (!(USPI_UBH(uspi)->bh[i] = sb_bread(sb, fragment + i)))
  			goto failed;
  	for (; i < UFS_MAXFRAG; i++)
  		USPI_UBH(uspi)->bh[i] = NULL;
  	return USPI_UBH(uspi);
  failed:
  	for (j = 0; j < i; j++)
  		brelse (USPI_UBH(uspi)->bh[j]);
  	return NULL;
  }
  
  void ubh_brelse (struct ufs_buffer_head * ubh)
  {
  	unsigned i;
  	if (!ubh)
  		return;
  	for (i = 0; i < ubh->count; i++)
  		brelse (ubh->bh[i]);
  	kfree (ubh);
  }
  
  void ubh_brelse_uspi (struct ufs_sb_private_info * uspi)
  {
  	unsigned i;
  	if (!USPI_UBH(uspi))
  		return;
  	for ( i = 0; i < USPI_UBH(uspi)->count; i++ ) {
  		brelse (USPI_UBH(uspi)->bh[i]);
  		USPI_UBH(uspi)->bh[i] = NULL;
  	}
  }
  
  void ubh_mark_buffer_dirty (struct ufs_buffer_head * ubh)
  {
  	unsigned i;
  	if (!ubh)
  		return;
  	for ( i = 0; i < ubh->count; i++ )
  		mark_buffer_dirty (ubh->bh[i]);
  }
  
  void ubh_mark_buffer_uptodate (struct ufs_buffer_head * ubh, int flag)
  {
  	unsigned i;
  	if (!ubh)
  		return;
  	if (flag) {
  		for ( i = 0; i < ubh->count; i++ )
  			set_buffer_uptodate (ubh->bh[i]);
  	} else {
  		for ( i = 0; i < ubh->count; i++ )
  			clear_buffer_uptodate (ubh->bh[i]);
  	}
  }
  
  void ubh_sync_block(struct ufs_buffer_head *ubh)
  {
  	if (ubh) {
  		unsigned i;
  
  		for (i = 0; i < ubh->count; i++)
  			write_dirty_buffer(ubh->bh[i], WRITE);
  
  		for (i = 0; i < ubh->count; i++)
  			wait_on_buffer(ubh->bh[i]);
  	}
  }
  
  void ubh_bforget (struct ufs_buffer_head * ubh)
  {
  	unsigned i;
  	if (!ubh) 
  		return;
  	for ( i = 0; i < ubh->count; i++ ) if ( ubh->bh[i] ) 
  		bforget (ubh->bh[i]);
  }
   
  int ubh_buffer_dirty (struct ufs_buffer_head * ubh)
  {
  	unsigned i;
  	unsigned result = 0;
  	if (!ubh)
  		return 0;
  	for ( i = 0; i < ubh->count; i++ )
  		result |= buffer_dirty(ubh->bh[i]);
  	return result;
  }
  
  void _ubh_ubhcpymem_(struct ufs_sb_private_info * uspi, 
  	unsigned char * mem, struct ufs_buffer_head * ubh, unsigned size)
  {
  	unsigned len, bhno;
  	if (size > (ubh->count << uspi->s_fshift))
  		size = ubh->count << uspi->s_fshift;
  	bhno = 0;
  	while (size) {
  		len = min_t(unsigned int, size, uspi->s_fsize);
  		memcpy (mem, ubh->bh[bhno]->b_data, len);
  		mem += uspi->s_fsize;
  		size -= len;
  		bhno++;
  	}
  }
  
  void _ubh_memcpyubh_(struct ufs_sb_private_info * uspi, 
  	struct ufs_buffer_head * ubh, unsigned char * mem, unsigned size)
  {
  	unsigned len, bhno;
  	if (size > (ubh->count << uspi->s_fshift))
  		size = ubh->count << uspi->s_fshift;
  	bhno = 0;
  	while (size) {
  		len = min_t(unsigned int, size, uspi->s_fsize);
  		memcpy (ubh->bh[bhno]->b_data, mem, len);
  		mem += uspi->s_fsize;
  		size -= len;
  		bhno++;
  	}
  }
  
  dev_t
  ufs_get_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi)
  {
  	__u32 fs32;
  	dev_t dev;
  
  	if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
  		fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[1]);
  	else
  		fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[0]);
  	switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
  	case UFS_ST_SUNx86:
  	case UFS_ST_SUN:
  		if ((fs32 & 0xffff0000) == 0 ||
  		    (fs32 & 0xffff0000) == 0xffff0000)
  			dev = old_decode_dev(fs32 & 0x7fff);
  		else
  			dev = MKDEV(sysv_major(fs32), sysv_minor(fs32));
  		break;
  
  	default:
  		dev = old_decode_dev(fs32);
  		break;
  	}
  	return dev;
  }
  
  void
  ufs_set_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi, dev_t dev)
  {
  	__u32 fs32;
  
  	switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
  	case UFS_ST_SUNx86:
  	case UFS_ST_SUN:
  		fs32 = sysv_encode_dev(dev);
  		if ((fs32 & 0xffff8000) == 0) {
  			fs32 = old_encode_dev(dev);
  		}
  		break;
  
  	default:
  		fs32 = old_encode_dev(dev);
  		break;
  	}
  	if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
  		ufsi->i_u1.i_data[1] = cpu_to_fs32(sb, fs32);
  	else
  		ufsi->i_u1.i_data[0] = cpu_to_fs32(sb, fs32);
  }
  
  /**
   * ufs_get_locked_page() - locate, pin and lock a pagecache page, if not exist
   * read it from disk.
   * @mapping: the address_space to search
   * @index: the page index
   *
   * Locates the desired pagecache page, if not exist we'll read it,
   * locks it, increments its reference
   * count and returns its address.
   *
   */
  
  struct page *ufs_get_locked_page(struct address_space *mapping,
  				 pgoff_t index)
  {
  	struct page *page;
  
  	page = find_lock_page(mapping, index);
  	if (!page) {
  		page = read_mapping_page(mapping, index, NULL);
  
  		if (IS_ERR(page)) {
  			printk(KERN_ERR "ufs_change_blocknr: "
  			       "read_mapping_page error: ino %lu, index: %lu
  ",
  			       mapping->host->i_ino, index);
  			goto out;
  		}
  
  		lock_page(page);
  
  		if (unlikely(page->mapping == NULL)) {
  			/* Truncate got there first */
  			unlock_page(page);
  			page_cache_release(page);
  			page = NULL;
  			goto out;
  		}
  
  		if (!PageUptodate(page) || PageError(page)) {
  			unlock_page(page);
  			page_cache_release(page);
  
  			printk(KERN_ERR "ufs_change_blocknr: "
  			       "can not read page: ino %lu, index: %lu
  ",
  			       mapping->host->i_ino, index);
  
  			page = ERR_PTR(-EIO);
  		}
  	}
  out:
  	return page;
  }