text: /*
   *  linux/fs/ufs/balloc.c
   *
   * Copyright (C) 1998
   * Daniel Pirkl <daniel.pirkl@email.cz>
   * Charles University, Faculty of Mathematics and Physics
   *
   * UFS2 write support Evgeniy Dushistov <dushistov@mail.ru>, 2007
   */
  
  #include <linux/fs.h>
  #include <linux/stat.h>
  #include <linux/time.h>
  #include <linux/string.h>
  #include <linux/buffer_head.h>
  #include <linux/capability.h>
  #include <linux/bitops.h>
  #include <asm/byteorder.h>
  
  #include "ufs_fs.h"
  #include "ufs.h"
  #include "swab.h"
  #include "util.h"
  
  #define INVBLOCK ((u64)-1L)
  
  static u64 ufs_add_fragments(struct inode *, u64, unsigned, unsigned);
  static u64 ufs_alloc_fragments(struct inode *, unsigned, u64, unsigned, int *);
  static u64 ufs_alloccg_block(struct inode *, struct ufs_cg_private_info *, u64, int *);
  static u64 ufs_bitmap_search (struct super_block *, struct ufs_cg_private_info *, u64, unsigned);
  static unsigned char ufs_fragtable_8fpb[], ufs_fragtable_other[];
  static void ufs_clusteracct(struct super_block *, struct ufs_cg_private_info *, unsigned, int);
  
  /*
   * Free 'count' fragments from fragment number 'fragment'
   */
  void ufs_free_fragments(struct inode *inode, u64 fragment, unsigned count)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	unsigned cgno, bit, end_bit, bbase, blkmap, i;
  	u64 blkno;
  	
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  	
  	UFSD("ENTER, fragment %llu, count %u\n",
  	     (unsigned long long)fragment, count);
  	
  	if (ufs_fragnum(fragment) + count > uspi->s_fpg)
  		ufs_error (sb, "ufs_free_fragments", "internal error");
  
  	mutex_lock(&UFS_SB(sb)->s_lock);
  	
  	cgno = ufs_dtog(uspi, fragment);
  	bit = ufs_dtogd(uspi, fragment);
  	if (cgno >= uspi->s_ncg) {
  		ufs_panic (sb, "ufs_free_fragments", "freeing blocks are outside device");
  		goto failed;
  	}
  		
  	ucpi = ufs_load_cylinder (sb, cgno);
  	if (!ucpi) 
  		goto failed;
  	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
  	if (!ufs_cg_chkmagic(sb, ucg)) {
  		ufs_panic (sb, "ufs_free_fragments", "internal error, bad magic number on cg %u", cgno);
  		goto failed;
  	}
  
  	end_bit = bit + count;
  	bbase = ufs_blknum (bit);
  	blkmap = ubh_blkmap (UCPI_UBH(ucpi), ucpi->c_freeoff, bbase);
  	ufs_fragacct (sb, blkmap, ucg->cg_frsum, -1);
  	for (i = bit; i < end_bit; i++) {
  		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, i))
  			ubh_setbit (UCPI_UBH(ucpi), ucpi->c_freeoff, i);
  		else 
  			ufs_error (sb, "ufs_free_fragments",
  				   "bit already cleared for fragment %u", i);
  	}
  
  	inode_sub_bytes(inode, count << uspi->s_fshift);
  	fs32_add(sb, &ucg->cg_cs.cs_nffree, count);
  	uspi->cs_total.cs_nffree += count;
  	fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
  	blkmap = ubh_blkmap (UCPI_UBH(ucpi), ucpi->c_freeoff, bbase);
  	ufs_fragacct(sb, blkmap, ucg->cg_frsum, 1);
  
  	/*
  	 * Trying to reassemble free fragments into block
  	 */
  	blkno = ufs_fragstoblks (bbase);
  	if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno)) {
  		fs32_sub(sb, &ucg->cg_cs.cs_nffree, uspi->s_fpb);
  		uspi->cs_total.cs_nffree -= uspi->s_fpb;
  		fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, uspi->s_fpb);
  		if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
  			ufs_clusteracct (sb, ucpi, blkno, 1);
  		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
  		uspi->cs_total.cs_nbfree++;
  		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nbfree, 1);
  		if (uspi->fs_magic != UFS2_MAGIC) {
  			unsigned cylno = ufs_cbtocylno (bbase);
  
  			fs16_add(sb, &ubh_cg_blks(ucpi, cylno,
  						  ufs_cbtorpos(bbase)), 1);
  			fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
  		}
  	}
  	
  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));
  	ufs_mark_sb_dirty(sb);
  
  	mutex_unlock(&UFS_SB(sb)->s_lock);
  	UFSD("EXIT\n");
  	return;
  
  failed:
  	mutex_unlock(&UFS_SB(sb)->s_lock);
  	UFSD("EXIT (FAILED)\n");
  	return;
  }
  
  /*
   * Free 'count' fragments from fragment number 'fragment' (free whole blocks)
   */
  void ufs_free_blocks(struct inode *inode, u64 fragment, unsigned count)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	unsigned overflow, cgno, bit, end_bit, i;
  	u64 blkno;
  	
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  
  	UFSD("ENTER, fragment %llu, count %u\n",
  	     (unsigned long long)fragment, count);
  	
  	if ((fragment & uspi->s_fpbmask) || (count & uspi->s_fpbmask)) {
  		ufs_error (sb, "ufs_free_blocks", "internal error, "
  			   "fragment %llu, count %u\n",
  			   (unsigned long long)fragment, count);
  		goto failed;
  	}
  
  	mutex_lock(&UFS_SB(sb)->s_lock);
  	
  do_more:
  	overflow = 0;
  	cgno = ufs_dtog(uspi, fragment);
  	bit = ufs_dtogd(uspi, fragment);
  	if (cgno >= uspi->s_ncg) {
  		ufs_panic (sb, "ufs_free_blocks", "freeing blocks are outside device");
  		goto failed_unlock;
  	}
  	end_bit = bit + count;
  	if (end_bit > uspi->s_fpg) {
  		overflow = bit + count - uspi->s_fpg;
  		count -= overflow;
  		end_bit -= overflow;
  	}
  
  	ucpi = ufs_load_cylinder (sb, cgno);
  	if (!ucpi) 
  		goto failed_unlock;
  	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
  	if (!ufs_cg_chkmagic(sb, ucg)) {
  		ufs_panic (sb, "ufs_free_blocks", "internal error, bad magic number on cg %u", cgno);
  		goto failed_unlock;
  	}
  
  	for (i = bit; i < end_bit; i += uspi->s_fpb) {
  		blkno = ufs_fragstoblks(i);
  		if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno)) {
  			ufs_error(sb, "ufs_free_blocks", "freeing free fragment");
  		}
  		ubh_setblock(UCPI_UBH(ucpi), ucpi->c_freeoff, blkno);
  		inode_sub_bytes(inode, uspi->s_fpb << uspi->s_fshift);
  		if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
  			ufs_clusteracct (sb, ucpi, blkno, 1);
  
  		fs32_add(sb, &ucg->cg_cs.cs_nbfree, 1);
  		uspi->cs_total.cs_nbfree++;
  		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nbfree, 1);
  
  		if (uspi->fs_magic != UFS2_MAGIC) {
  			unsigned cylno = ufs_cbtocylno(i);
  
  			fs16_add(sb, &ubh_cg_blks(ucpi, cylno,
  						  ufs_cbtorpos(i)), 1);
  			fs32_add(sb, &ubh_cg_blktot(ucpi, cylno), 1);
  		}
  	}
  
  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));
  
  	if (overflow) {
  		fragment += count;
  		count = overflow;
  		goto do_more;
  	}
  
  	ufs_mark_sb_dirty(sb);
  	mutex_unlock(&UFS_SB(sb)->s_lock);
  	UFSD("EXIT\n");
  	return;
  
  failed_unlock:
  	mutex_unlock(&UFS_SB(sb)->s_lock);
  failed:
  	UFSD("EXIT (FAILED)\n");
  	return;
  }
  
  /*
   * Modify inode page cache in such way:
   * have - blocks with b_blocknr equal to oldb...oldb+count-1
   * get - blocks with b_blocknr equal to newb...newb+count-1
   * also we suppose that oldb...oldb+count-1 blocks
   * situated at the end of file.
   *
   * We can come here from ufs_writepage or ufs_prepare_write,
   * locked_page is argument of these functions, so we already lock it.
   */
  static void ufs_change_blocknr(struct inode *inode, sector_t beg,
  			       unsigned int count, sector_t oldb,
  			       sector_t newb, struct page *locked_page)
  {
  	const unsigned blks_per_page =
  		1 << (PAGE_SHIFT - inode->i_blkbits);
  	const unsigned mask = blks_per_page - 1;
  	struct address_space * const mapping = inode->i_mapping;
  	pgoff_t index, cur_index, last_index;
  	unsigned pos, j, lblock;
  	sector_t end, i;
  	struct page *page;
  	struct buffer_head *head, *bh;
  
  	UFSD("ENTER, ino %lu, count %u, oldb %llu, newb %llu\n",
  	      inode->i_ino, count,
  	     (unsigned long long)oldb, (unsigned long long)newb);
  
  	BUG_ON(!locked_page);
  	BUG_ON(!PageLocked(locked_page));
  
  	cur_index = locked_page->index;
  	end = count + beg;
  	last_index = end >> (PAGE_SHIFT - inode->i_blkbits);
  	for (i = beg; i < end; i = (i | mask) + 1) {
  		index = i >> (PAGE_SHIFT - inode->i_blkbits);
  
  		if (likely(cur_index != index)) {
  			page = ufs_get_locked_page(mapping, index);
  			if (!page)/* it was truncated */
  				continue;
  			if (IS_ERR(page)) {/* or EIO */
  				ufs_error(inode->i_sb, __func__,
  					  "read of page %llu failed\n",
  					  (unsigned long long)index);
  				continue;
  			}
  		} else
  			page = locked_page;
  
  		head = page_buffers(page);
  		bh = head;
  		pos = i & mask;
  		for (j = 0; j < pos; ++j)
  			bh = bh->b_this_page;
  
  
  		if (unlikely(index == last_index))
  			lblock = end & mask;
  		else
  			lblock = blks_per_page;
  
  		do {
  			if (j >= lblock)
  				break;
  			pos = (i - beg) + j;
  
  			if (!buffer_mapped(bh))
  					map_bh(bh, inode->i_sb, oldb + pos);
  			if (!buffer_uptodate(bh)) {
  				ll_rw_block(REQ_OP_READ, 0, 1, &bh);
  				wait_on_buffer(bh);
  				if (!buffer_uptodate(bh)) {
  					ufs_error(inode->i_sb, __func__,
  						  "read of block failed\n");
  					break;
  				}
  			}
  
  			UFSD(" change from %llu to %llu, pos %u\n",
  			     (unsigned long long)(pos + oldb),
  			     (unsigned long long)(pos + newb), pos);
  
  			bh->b_blocknr = newb + pos;
  			unmap_underlying_metadata(bh->b_bdev,
  						  bh->b_blocknr);
  			mark_buffer_dirty(bh);
  			++j;
  			bh = bh->b_this_page;
  		} while (bh != head);
  
  		if (likely(cur_index != index))
  			ufs_put_locked_page(page);
   	}
  	UFSD("EXIT\n");
  }
  
  static void ufs_clear_frags(struct inode *inode, sector_t beg, unsigned int n,
  			    int sync)
  {
  	struct buffer_head *bh;
  	sector_t end = beg + n;
  
  	for (; beg < end; ++beg) {
  		bh = sb_getblk(inode->i_sb, beg);
  		lock_buffer(bh);
  		memset(bh->b_data, 0, inode->i_sb->s_blocksize);
  		set_buffer_uptodate(bh);
  		mark_buffer_dirty(bh);
  		unlock_buffer(bh);
  		if (IS_SYNC(inode) || sync)
  			sync_dirty_buffer(bh);
  		brelse(bh);
  	}
  }
  
  u64 ufs_new_fragments(struct inode *inode, void *p, u64 fragment,
  			   u64 goal, unsigned count, int *err,
  			   struct page *locked_page)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_super_block_first * usb1;
  	unsigned cgno, oldcount, newcount;
  	u64 tmp, request, result;
  	
  	UFSD("ENTER, ino %lu, fragment %llu, goal %llu, count %u\n",
  	     inode->i_ino, (unsigned long long)fragment,
  	     (unsigned long long)goal, count);
  	
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  	usb1 = ubh_get_usb_first(uspi);
  	*err = -ENOSPC;
  
  	mutex_lock(&UFS_SB(sb)->s_lock);
  	tmp = ufs_data_ptr_to_cpu(sb, p);
  
  	if (count + ufs_fragnum(fragment) > uspi->s_fpb) {
  		ufs_warning(sb, "ufs_new_fragments", "internal warning"
  			    " fragment %llu, count %u",
  			    (unsigned long long)fragment, count);
  		count = uspi->s_fpb - ufs_fragnum(fragment); 
  	}
  	oldcount = ufs_fragnum (fragment);
  	newcount = oldcount + count;
  
  	/*
  	 * Somebody else has just allocated our fragments
  	 */
  	if (oldcount) {
  		if (!tmp) {
  			ufs_error(sb, "ufs_new_fragments", "internal error, "
  				  "fragment %llu, tmp %llu\n",
  				  (unsigned long long)fragment,
  				  (unsigned long long)tmp);
  			mutex_unlock(&UFS_SB(sb)->s_lock);
  			return INVBLOCK;
  		}
  		if (fragment < UFS_I(inode)->i_lastfrag) {
  			UFSD("EXIT (ALREADY ALLOCATED)\n");
  			mutex_unlock(&UFS_SB(sb)->s_lock);
  			return 0;
  		}
  	}
  	else {
  		if (tmp) {
  			UFSD("EXIT (ALREADY ALLOCATED)\n");
  			mutex_unlock(&UFS_SB(sb)->s_lock);
  			return 0;
  		}
  	}
  
  	/*
  	 * There is not enough space for user on the device
  	 */
  	if (!capable(CAP_SYS_RESOURCE) && ufs_freespace(uspi, UFS_MINFREE) <= 0) {
  		mutex_unlock(&UFS_SB(sb)->s_lock);
  		UFSD("EXIT (FAILED)\n");
  		return 0;
  	}
  
  	if (goal >= uspi->s_size) 
  		goal = 0;
  	if (goal == 0) 
  		cgno = ufs_inotocg (inode->i_ino);
  	else
  		cgno = ufs_dtog(uspi, goal);
  	 
  	/*
  	 * allocate new fragment
  	 */
  	if (oldcount == 0) {
  		result = ufs_alloc_fragments (inode, cgno, goal, count, err);
  		if (result) {
  			ufs_clear_frags(inode, result + oldcount,
  					newcount - oldcount, locked_page != NULL);
  			write_seqlock(&UFS_I(inode)->meta_lock);
  			ufs_cpu_to_data_ptr(sb, p, result);
  			write_sequnlock(&UFS_I(inode)->meta_lock);
  			*err = 0;
  			UFS_I(inode)->i_lastfrag =
  				max(UFS_I(inode)->i_lastfrag, fragment + count);
  		}
  		mutex_unlock(&UFS_SB(sb)->s_lock);
  		UFSD("EXIT, result %llu\n", (unsigned long long)result);
  		return result;
  	}
  
  	/*
  	 * resize block
  	 */
  	result = ufs_add_fragments(inode, tmp, oldcount, newcount);
  	if (result) {
  		*err = 0;
  		UFS_I(inode)->i_lastfrag = max(UFS_I(inode)->i_lastfrag,
  						fragment + count);
  		ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
  				locked_page != NULL);
  		mutex_unlock(&UFS_SB(sb)->s_lock);
  		UFSD("EXIT, result %llu\n", (unsigned long long)result);
  		return result;
  	}
  
  	/*
  	 * allocate new block and move data
  	 */
  	switch (fs32_to_cpu(sb, usb1->fs_optim)) {
  	    case UFS_OPTSPACE:
  		request = newcount;
  		if (uspi->s_minfree < 5 || uspi->cs_total.cs_nffree
  		    > uspi->s_dsize * uspi->s_minfree / (2 * 100))
  			break;
  		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
  		break;
  	    default:
  		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
  	
  	    case UFS_OPTTIME:
  		request = uspi->s_fpb;
  		if (uspi->cs_total.cs_nffree < uspi->s_dsize *
  		    (uspi->s_minfree - 2) / 100)
  			break;
  		usb1->fs_optim = cpu_to_fs32(sb, UFS_OPTTIME);
  		break;
  	}
  	result = ufs_alloc_fragments (inode, cgno, goal, request, err);
  	if (result) {
  		ufs_clear_frags(inode, result + oldcount, newcount - oldcount,
  				locked_page != NULL);
  		ufs_change_blocknr(inode, fragment - oldcount, oldcount,
  				   uspi->s_sbbase + tmp,
  				   uspi->s_sbbase + result, locked_page);
  		write_seqlock(&UFS_I(inode)->meta_lock);
  		ufs_cpu_to_data_ptr(sb, p, result);
  		write_sequnlock(&UFS_I(inode)->meta_lock);
  		*err = 0;
  		UFS_I(inode)->i_lastfrag = max(UFS_I(inode)->i_lastfrag,
  						fragment + count);
  		mutex_unlock(&UFS_SB(sb)->s_lock);
  		if (newcount < request)
  			ufs_free_fragments (inode, result + newcount, request - newcount);
  		ufs_free_fragments (inode, tmp, oldcount);
  		UFSD("EXIT, result %llu\n", (unsigned long long)result);
  		return result;
  	}
  
  	mutex_unlock(&UFS_SB(sb)->s_lock);
  	UFSD("EXIT (FAILED)\n");
  	return 0;
  }		
  
  static bool try_add_frags(struct inode *inode, unsigned frags)
  {
  	unsigned size = frags * i_blocksize(inode);
  	spin_lock(&inode->i_lock);
  	__inode_add_bytes(inode, size);
  	if (unlikely((u32)inode->i_blocks != inode->i_blocks)) {
  		__inode_sub_bytes(inode, size);
  		spin_unlock(&inode->i_lock);
  		return false;
  	}
  	spin_unlock(&inode->i_lock);
  	return true;
  }
  
  static u64 ufs_add_fragments(struct inode *inode, u64 fragment,
  			     unsigned oldcount, unsigned newcount)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	unsigned cgno, fragno, fragoff, count, fragsize, i;
  	
  	UFSD("ENTER, fragment %llu, oldcount %u, newcount %u\n",
  	     (unsigned long long)fragment, oldcount, newcount);
  	
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  	count = newcount - oldcount;
  	
  	cgno = ufs_dtog(uspi, fragment);
  	if (fs32_to_cpu(sb, UFS_SB(sb)->fs_cs(cgno).cs_nffree) < count)
  		return 0;
  	if ((ufs_fragnum (fragment) + newcount) > uspi->s_fpb)
  		return 0;
  	ucpi = ufs_load_cylinder (sb, cgno);
  	if (!ucpi)
  		return 0;
  	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
  	if (!ufs_cg_chkmagic(sb, ucg)) {
  		ufs_panic (sb, "ufs_add_fragments",
  			"internal error, bad magic number on cg %u", cgno);
  		return 0;
  	}
  
  	fragno = ufs_dtogd(uspi, fragment);
  	fragoff = ufs_fragnum (fragno);
  	for (i = oldcount; i < newcount; i++)
  		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i))
  			return 0;
  
  	if (!try_add_frags(inode, count))
  		return 0;
  	/*
  	 * Block can be extended
  	 */
  	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
  	for (i = newcount; i < (uspi->s_fpb - fragoff); i++)
  		if (ubh_isclr (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i))
  			break;
  	fragsize = i - oldcount;
  	if (!fs32_to_cpu(sb, ucg->cg_frsum[fragsize]))
  		ufs_panic (sb, "ufs_add_fragments",
  			"internal error or corrupted bitmap on cg %u", cgno);
  	fs32_sub(sb, &ucg->cg_frsum[fragsize], 1);
  	if (fragsize != count)
  		fs32_add(sb, &ucg->cg_frsum[fragsize - count], 1);
  	for (i = oldcount; i < newcount; i++)
  		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_freeoff, fragno + i);
  
  	fs32_sub(sb, &ucg->cg_cs.cs_nffree, count);
  	fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
  	uspi->cs_total.cs_nffree -= count;
  	
  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));
  	ufs_mark_sb_dirty(sb);
  
  	UFSD("EXIT, fragment %llu\n", (unsigned long long)fragment);
  	
  	return fragment;
  }
  
  #define UFS_TEST_FREE_SPACE_CG \
  	ucg = (struct ufs_cylinder_group *) UFS_SB(sb)->s_ucg[cgno]->b_data; \
  	if (fs32_to_cpu(sb, ucg->cg_cs.cs_nbfree)) \
  		goto cg_found; \
  	for (k = count; k < uspi->s_fpb; k++) \
  		if (fs32_to_cpu(sb, ucg->cg_frsum[k])) \
  			goto cg_found; 
  
  static u64 ufs_alloc_fragments(struct inode *inode, unsigned cgno,
  			       u64 goal, unsigned count, int *err)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_cg_private_info * ucpi;
  	struct ufs_cylinder_group * ucg;
  	unsigned oldcg, i, j, k, allocsize;
  	u64 result;
  	
  	UFSD("ENTER, ino %lu, cgno %u, goal %llu, count %u\n",
  	     inode->i_ino, cgno, (unsigned long long)goal, count);
  
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  	oldcg = cgno;
  	
  	/*
  	 * 1. searching on preferred cylinder group
  	 */
  	UFS_TEST_FREE_SPACE_CG
  
  	/*
  	 * 2. quadratic rehash
  	 */
  	for (j = 1; j < uspi->s_ncg; j *= 2) {
  		cgno += j;
  		if (cgno >= uspi->s_ncg) 
  			cgno -= uspi->s_ncg;
  		UFS_TEST_FREE_SPACE_CG
  	}
  
  	/*
  	 * 3. brute force search
  	 * We start at i = 2 ( 0 is checked at 1.step, 1 at 2.step )
  	 */
  	cgno = (oldcg + 1) % uspi->s_ncg;
  	for (j = 2; j < uspi->s_ncg; j++) {
  		cgno++;
  		if (cgno >= uspi->s_ncg)
  			cgno = 0;
  		UFS_TEST_FREE_SPACE_CG
  	}
  	
  	UFSD("EXIT (FAILED)\n");
  	return 0;
  
  cg_found:
  	ucpi = ufs_load_cylinder (sb, cgno);
  	if (!ucpi)
  		return 0;
  	ucg = ubh_get_ucg (UCPI_UBH(ucpi));
  	if (!ufs_cg_chkmagic(sb, ucg)) 
  		ufs_panic (sb, "ufs_alloc_fragments",
  			"internal error, bad magic number on cg %u", cgno);
  	ucg->cg_time = cpu_to_fs32(sb, get_seconds());
  
  	if (count == uspi->s_fpb) {
  		result = ufs_alloccg_block (inode, ucpi, goal, err);
  		if (result == INVBLOCK)
  			return 0;
  		goto succed;
  	}
  
  	for (allocsize = count; allocsize < uspi->s_fpb; allocsize++)
  		if (fs32_to_cpu(sb, ucg->cg_frsum[allocsize]) != 0)
  			break;
  	
  	if (allocsize == uspi->s_fpb) {
  		result = ufs_alloccg_block (inode, ucpi, goal, err);
  		if (result == INVBLOCK)
  			return 0;
  		goal = ufs_dtogd(uspi, result);
  		for (i = count; i < uspi->s_fpb; i++)
  			ubh_setbit (UCPI_UBH(ucpi), ucpi->c_freeoff, goal + i);
  		i = uspi->s_fpb - count;
  
  		inode_sub_bytes(inode, i << uspi->s_fshift);
  		fs32_add(sb, &ucg->cg_cs.cs_nffree, i);
  		uspi->cs_total.cs_nffree += i;
  		fs32_add(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, i);
  		fs32_add(sb, &ucg->cg_frsum[i], 1);
  		goto succed;
  	}
  
  	result = ufs_bitmap_search (sb, ucpi, goal, allocsize);
  	if (result == INVBLOCK)
  		return 0;
  	if (!try_add_frags(inode, count))
  		return 0;
  	for (i = 0; i < count; i++)
  		ubh_clrbit (UCPI_UBH(ucpi), ucpi->c_freeoff, result + i);
  	
  	fs32_sub(sb, &ucg->cg_cs.cs_nffree, count);
  	uspi->cs_total.cs_nffree -= count;
  	fs32_sub(sb, &UFS_SB(sb)->fs_cs(cgno).cs_nffree, count);
  	fs32_sub(sb, &ucg->cg_frsum[allocsize], 1);
  
  	if (count != allocsize)
  		fs32_add(sb, &ucg->cg_frsum[allocsize - count], 1);
  
  succed:
  	ubh_mark_buffer_dirty (USPI_UBH(uspi));
  	ubh_mark_buffer_dirty (UCPI_UBH(ucpi));
  	if (sb->s_flags & MS_SYNCHRONOUS)
  		ubh_sync_block(UCPI_UBH(ucpi));
  	ufs_mark_sb_dirty(sb);
  
  	result += cgno * uspi->s_fpg;
  	UFSD("EXIT3, result %llu\n", (unsigned long long)result);
  	return result;
  }
  
  static u64 ufs_alloccg_block(struct inode *inode,
  			     struct ufs_cg_private_info *ucpi,
  			     u64 goal, int *err)
  {
  	struct super_block * sb;
  	struct ufs_sb_private_info * uspi;
  	struct ufs_cylinder_group * ucg;
  	u64 result, blkno;
  
  	UFSD("ENTER, goal %llu\n", (unsigned long long)goal);
  
  	sb = inode->i_sb;
  	uspi = UFS_SB(sb)->s_uspi;
  	ucg = ubh_get_ucg(UCPI_UBH(ucpi));
  
  	if (goal == 0) {
  		goal = ucpi->c_rotor;
  		goto norot;
  	}
  	goal = ufs_blknum (goal);
  	goal = ufs_dtogd(uspi, goal);
  	
  	/*
  	 * If the requested block is available, use it.
  	 */
  	if (ubh_isblockset(UCPI_UBH(ucpi), ucpi->c_freeoff, ufs_fragstoblks(goal))) {
  		result = goal;
  		goto gotit;
  	}
  	
  norot:	
  	result = ufs_bitmap_search (sb, ucpi, goal, uspi->s_fpb);
  	if (result == INVBLOCK)
  		return INVBLOCK;
  	ucpi->c_rotor = result;
  gotit:
  	if (!try_add_frags(inode, uspi->s_fpb))
  		return 0;
  	blkno = ufs_fragstoblks(result);
  	ubh_clrblock (UCPI_UBH(ucpi), ucpi->c_freeoff, blkno);
  	if ((UFS_SB(sb)->s_flags & UFS_CG_MASK) == UFS_CG_44BSD)
  		ufs_clusteracct (sb, ucpi, blkno, -1);
  
  	fs32_sub(sb, &ucg->cg_cs.cs_nbfree, 1);
  	uspi->cs_total.cs_nbfree--;
  	fs32_sub(sb, &UFS_SB(sb)->fs_cs(ucpi->c_cgx).cs_nbfree, 1);
  
  	if (uspi->fs_magic != UFS2_MAGIC) {
  		unsigned cylno = ufs_cbtocylno((unsigned)result);
  
  		fs16_sub(sb, &ubh_cg_blks(ucpi, cylno,
  					  ufs_cbtorpos((unsigned)result)), 1);
  		fs32_sub(sb, &ubh_cg_blktot(ucpi, cylno), 1);
  	}
  	
  	UFSD("EXIT, result %llu\n", (unsigned long long)result);
  
  	return result;
  }
  
  static unsigned ubh_scanc(struct ufs_sb_private_info *uspi,
  			  struct ufs_buffer_head *ubh,
  			  unsigned begin, unsigned size,
  			  unsigned char *table, unsigned char mask)
  {
  	unsigned rest, offset;
  	unsigned char *cp;
  	
  
  	offset = begin & ~uspi->s_fmask;
  	begin >>= uspi->s_fshift;
  	for (;;) {
  		if ((offset + size) < uspi->s_fsize)
  			rest = size;
  		else
  			rest = uspi->s_fsize - offset;
  		size -= rest;
  		cp = ubh->bh[begin]->b_data + offset;
  		while ((table[*cp++] & mask) == 0 && --rest)
  			;
  		if (rest || !size)
  			break;
  		begin++;
  		offset = 0;
  	}
  	return (size + rest);
  }
  
  /*
   * Find a block of the specified size in the specified cylinder group.
   * @sp: pointer to super block
   * @ucpi: pointer to cylinder group info
   * @goal: near which block we want find new one
   * @count: specified size
   */
  static u64 ufs_bitmap_search(struct super_block *sb,
  			     struct ufs_cg_private_info *ucpi,
  			     u64 goal, unsigned count)
  {
  	/*
  	 * Bit patterns for identifying fragments in the block map
  	 * used as ((map & mask_arr) == want_arr)
  	 */
  	static const int mask_arr[9] = {
  		0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff
  	};
  	static const int want_arr[9] = {
  		0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe
  	};
  	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
  	unsigned start, length, loc;
  	unsigned pos, want, blockmap, mask, end;
  	u64 result;
  
  	UFSD("ENTER, cg %u, goal %llu, count %u\n", ucpi->c_cgx,
  	     (unsigned long long)goal, count);
  
  	if (goal)
  		start = ufs_dtogd(uspi, goal) >> 3;
  	else
  		start = ucpi->c_frotor >> 3;
  		
  	length = ((uspi->s_fpg + 7) >> 3) - start;
  	loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff + start, length,
  		(uspi->s_fpb == 8) ? ufs_fragtable_8fpb : ufs_fragtable_other,
  		1 << (count - 1 + (uspi->s_fpb & 7))); 
  	if (loc == 0) {
  		length = start + 1;
  		loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff, length,
  				(uspi->s_fpb == 8) ? ufs_fragtable_8fpb :
  				ufs_fragtable_other,
  				1 << (count - 1 + (uspi->s_fpb & 7)));
  		if (loc == 0) {
  			ufs_error(sb, "ufs_bitmap_search",
  				  "bitmap corrupted on cg %u, start %u,"
  				  " length %u, count %u, freeoff %u\n",
  				  ucpi->c_cgx, start, length, count,
  				  ucpi->c_freeoff);
  			return INVBLOCK;
  		}
  		start = 0;
  	}
  	result = (start + length - loc) << 3;
  	ucpi->c_frotor = result;
  
  	/*
  	 * found the byte in the map
  	 */
  
  	for (end = result + 8; result < end; result += uspi->s_fpb) {
  		blockmap = ubh_blkmap(UCPI_UBH(ucpi), ucpi->c_freeoff, result);
  		blockmap <<= 1;
  		mask = mask_arr[count];
  		want = want_arr[count];
  		for (pos = 0; pos <= uspi->s_fpb - count; pos++) {
  			if ((blockmap & mask) == want) {
  				UFSD("EXIT, result %llu\n",
  				     (unsigned long long)result);
  				return result + pos;
   			}
  			mask <<= 1;
  			want <<= 1;
   		}
   	}
  
  	ufs_error(sb, "ufs_bitmap_search", "block not in map on cg %u\n",
  		  ucpi->c_cgx);
  	UFSD("EXIT (FAILED)\n");
  	return INVBLOCK;
  }
  
  static void ufs_clusteracct(struct super_block * sb,
  	struct ufs_cg_private_info * ucpi, unsigned blkno, int cnt)
  {
  	struct ufs_sb_private_info * uspi;
  	int i, start, end, forw, back;
  	
  	uspi = UFS_SB(sb)->s_uspi;
  	if (uspi->s_contigsumsize <= 0)
  		return;
  
  	if (cnt > 0)
  		ubh_setbit(UCPI_UBH(ucpi), ucpi->c_clusteroff, blkno);
  	else
  		ubh_clrbit(UCPI_UBH(ucpi), ucpi->c_clusteroff, blkno);
  
  	/*
  	 * Find the size of the cluster going forward.
  	 */
  	start = blkno + 1;
  	end = start + uspi->s_contigsumsize;
  	if ( end >= ucpi->c_nclusterblks)
  		end = ucpi->c_nclusterblks;
  	i = ubh_find_next_zero_bit (UCPI_UBH(ucpi), ucpi->c_clusteroff, end, start);
  	if (i > end)
  		i = end;
  	forw = i - start;
  	
  	/*
  	 * Find the size of the cluster going backward.
  	 */
  	start = blkno - 1;
  	end = start - uspi->s_contigsumsize;
  	if (end < 0 ) 
  		end = -1;
  	i = ubh_find_last_zero_bit (UCPI_UBH(ucpi), ucpi->c_clusteroff, start, end);
  	if ( i < end) 
  		i = end;
  	back = start - i;
  	
  	/*
  	 * Account for old cluster and the possibly new forward and
  	 * back clusters.
  	 */
  	i = back + forw + 1;
  	if (i > uspi->s_contigsumsize)
  		i = uspi->s_contigsumsize;
  	fs32_add(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (i << 2)), cnt);
  	if (back > 0)
  		fs32_sub(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (back << 2)), cnt);
  	if (forw > 0)
  		fs32_sub(sb, (__fs32*)ubh_get_addr(UCPI_UBH(ucpi), ucpi->c_clustersumoff + (forw << 2)), cnt);
  }
  
  
  static unsigned char ufs_fragtable_8fpb[] = {
  	0x00, 0x01, 0x01, 0x02, 0x01, 0x01, 0x02, 0x04, 0x01, 0x01, 0x01, 0x03, 0x02, 0x03, 0x04, 0x08,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x02, 0x03, 0x03, 0x02, 0x04, 0x05, 0x08, 0x10,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
  	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x04, 0x05, 0x05, 0x06, 0x08, 0x09, 0x10, 0x20,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,	
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
  	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0A,
  	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04, 0x08, 0x09, 0x09, 0x0A, 0x10, 0x11, 0x20, 0x40,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x03, 0x03, 0x03, 0x03, 0x05, 0x05, 0x09, 0x11,
  	0x01, 0x01, 0x01, 0x03, 0x01, 0x01, 0x03, 0x05, 0x01, 0x01, 0x01, 0x03, 0x03, 0x03, 0x05, 0x09,
  	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07, 0x05, 0x05, 0x05, 0x07, 0x09, 0x09, 0x11, 0x21,
  	0x02, 0x03, 0x03, 0x02, 0x03, 0x03, 0x02, 0x06, 0x03, 0x03, 0x03, 0x03, 0x02, 0x03, 0x06, 0x0A,
  	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x07, 0x02, 0x03, 0x03, 0x02, 0x06, 0x07, 0x0A, 0x12,
  	0x04, 0x05, 0x05, 0x06, 0x05, 0x05, 0x06, 0x04, 0x05, 0x05, 0x05, 0x07, 0x06, 0x07, 0x04, 0x0C,
  	0x08, 0x09, 0x09, 0x0A, 0x09, 0x09, 0x0A, 0x0C, 0x10, 0x11, 0x11, 0x12, 0x20, 0x21, 0x40, 0x80,
  };
  
  static unsigned char ufs_fragtable_other[] = {
  	0x00, 0x16, 0x16, 0x2A, 0x16, 0x16, 0x26, 0x4E, 0x16, 0x16, 0x16, 0x3E, 0x2A, 0x3E, 0x4E, 0x8A,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x2A, 0x3E, 0x3E, 0x2A, 0x3E, 0x3E, 0x2E, 0x6E, 0x3E, 0x3E, 0x3E, 0x3E, 0x2A, 0x3E, 0x6E, 0xAA,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x26, 0x36, 0x36, 0x2E, 0x36, 0x36, 0x26, 0x6E, 0x36, 0x36, 0x36, 0x3E, 0x2E, 0x3E, 0x6E, 0xAE,
  	0x4E, 0x5E, 0x5E, 0x6E, 0x5E, 0x5E, 0x6E, 0x4E, 0x5E, 0x5E, 0x5E, 0x7E, 0x6E, 0x7E, 0x4E, 0xCE,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x16, 0x16, 0x16, 0x3E, 0x16, 0x16, 0x36, 0x5E, 0x16, 0x16, 0x16, 0x3E, 0x3E, 0x3E, 0x5E, 0x9E,
  	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0xBE,
  	0x2A, 0x3E, 0x3E, 0x2A, 0x3E, 0x3E, 0x2E, 0x6E, 0x3E, 0x3E, 0x3E, 0x3E, 0x2A, 0x3E, 0x6E, 0xAA,
  	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E,	0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x3E, 0x7E, 0xBE,
  	0x4E, 0x5E, 0x5E, 0x6E, 0x5E, 0x5E, 0x6E, 0x4E, 0x5E, 0x5E, 0x5E, 0x7E, 0x6E, 0x7E, 0x4E, 0xCE,
  	0x8A, 0x9E, 0x9E, 0xAA, 0x9E, 0x9E, 0xAE, 0xCE, 0x9E, 0x9E, 0x9E, 0xBE, 0xAA, 0xBE, 0xCE, 0x8A,
  };
  