inode.c

这是Linux系统下的对UDF文件系统新增的功能

		if (!goal)
		{
			if (!(goal = pgoal))
				goal = UDF_I_LOCATION(inode).logicalBlockNum + 1;
		}

		if (!(newblocknum = udf_new_block(inode->i_sb, inode,
			UDF_I_LOCATION(inode).partitionReferenceNum, goal, err)))
		{
			udf_release_data(pbh);
			*err = -ENOSPC;
			return NULL;
		}
		UDF_I_LENEXTENTS(inode) += inode->i_sb->s_blocksize;
	}

	/* if the extent the requsted block is located in contains multiple blocks,
       split the extent into at most three extents. blocks prior to requested
       block, requested block, and blocks after requested block */
	udf_split_extents(inode, &c, offset, newblocknum, laarr, &endnum);

#ifdef UDF_PREALLOCATE
	/* preallocate blocks */
	udf_prealloc_extents(inode, c, lastblock, laarr, &endnum);
#endif

	/* merge any continuous blocks in laarr */
	udf_merge_extents(inode, laarr, &endnum);

	/* write back the new extents, inserting new extents if the new number
       of extents is greater than the old number, and deleting extents if
       the new number of extents is less than the old number */
	udf_update_extents(inode, laarr, startnum, endnum, pbloc, pextoffset, &pbh);

	udf_release_data(pbh);

	if (!(newblock = udf_get_pblock(inode->i_sb, newblocknum,
		UDF_I_LOCATION(inode).partitionReferenceNum, 0)))
	{
		return NULL;
	}
	*phys = newblock;
	*err = 0;
	*new = 1;
	UDF_I_NEXT_ALLOC_BLOCK(inode) = block;
	UDF_I_NEXT_ALLOC_GOAL(inode) = newblocknum;
	inode->i_ctime = CURRENT_TIME;

	if (IS_SYNC(inode))
		udf_sync_inode(inode);
	else
		mark_inode_dirty(inode);
	return result;
}

static void udf_split_extents(struct inode *inode, int *c, int offset, int newblocknum,
	long_ad laarr[EXTENT_MERGE_SIZE], int *endnum)
{
	if ((laarr[*c].extLength >> 30) == (EXT_NOT_RECORDED_ALLOCATED >> 30) ||
		(laarr[*c].extLength >> 30) == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
	{
		int curr = *c;
		int blen = ((laarr[curr].extLength & UDF_EXTENT_LENGTH_MASK) +
			inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
		int8_t etype = (laarr[curr].extLength >> 30);

		if (blen == 1)
			;
		else if (!offset || blen == offset + 1)
		{
			laarr[curr+2] = laarr[curr+1];
			laarr[curr+1] = laarr[curr];
		}
		else
		{
			laarr[curr+3] = laarr[curr+1];
			laarr[curr+2] = laarr[curr+1] = laarr[curr];
		}

		if (offset)
		{
			if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
			{
				udf_free_blocks(inode->i_sb, inode, laarr[curr].extLocation, 0, offset);
				laarr[curr].extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |
					(offset << inode->i_sb->s_blocksize_bits);
				laarr[curr].extLocation.logicalBlockNum = 0;
				laarr[curr].extLocation.partitionReferenceNum = 0;
			}
			else
				laarr[curr].extLength = (etype << 30) |
					(offset << inode->i_sb->s_blocksize_bits);
			curr ++;
			(*c) ++;
			(*endnum) ++;
		}
		
		laarr[curr].extLocation.logicalBlockNum = newblocknum;
		if (etype == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
			laarr[curr].extLocation.partitionReferenceNum =
				UDF_I_LOCATION(inode).partitionReferenceNum;
		laarr[curr].extLength = EXT_RECORDED_ALLOCATED |
			inode->i_sb->s_blocksize;
		curr ++;

		if (blen != offset + 1)
		{
			if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
				laarr[curr].extLocation.logicalBlockNum += (offset + 1);
			laarr[curr].extLength = (etype << 30) |
				((blen - (offset + 1)) << inode->i_sb->s_blocksize_bits);
			curr ++;
			(*endnum) ++;
		}
	}
}

static void udf_prealloc_extents(struct inode *inode, int c, int lastblock,
	 long_ad laarr[EXTENT_MERGE_SIZE], int *endnum)
{
	int start, length = 0, currlength = 0, i;

	if (*endnum >= (c+1))
	{
		if (!lastblock)
			return;
		else
			start = c;
	}
	else
	{
		if ((laarr[c+1].extLength >> 30) == (EXT_NOT_RECORDED_ALLOCATED >> 30))
		{
			start = c+1;
			length = currlength = (((laarr[c+1].extLength & UDF_EXTENT_LENGTH_MASK) +
				inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits);
		}
		else
			start = c;
	}

	for (i=start+1; i<=*endnum; i++)
	{
		if (i == *endnum)
		{
			if (lastblock)
				length += UDF_DEFAULT_PREALLOC_BLOCKS;
		}
		else if ((laarr[i].extLength >> 30) == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
			length += (((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
				inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits);
		else
			break;
	}

	if (length)
	{
		int next = laarr[start].extLocation.logicalBlockNum +
			(((laarr[start].extLength & UDF_EXTENT_LENGTH_MASK) +
			inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits);
		int numalloc = udf_prealloc_blocks(inode->i_sb, inode,
			laarr[start].extLocation.partitionReferenceNum,
			next, (UDF_DEFAULT_PREALLOC_BLOCKS > length ? length :
				UDF_DEFAULT_PREALLOC_BLOCKS) - currlength);

		if (numalloc)
		{
			if (start == (c+1))
				laarr[start].extLength +=
					(numalloc << inode->i_sb->s_blocksize_bits);
			else
			{
				memmove(&laarr[c+2], &laarr[c+1],
					sizeof(long_ad) * (*endnum - (c+1)));
				(*endnum) ++;
				laarr[c+1].extLocation.logicalBlockNum = next;
				laarr[c+1].extLocation.partitionReferenceNum =
					laarr[c].extLocation.partitionReferenceNum;
				laarr[c+1].extLength = EXT_NOT_RECORDED_ALLOCATED |
					(numalloc << inode->i_sb->s_blocksize_bits);
				start = c+1;
			}

			for (i=start+1; numalloc && i<*endnum; i++)
			{
				int elen = ((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
					inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;

				if (elen > numalloc)
				{
					laarr[i].extLength -=
						(numalloc << inode->i_sb->s_blocksize_bits);
					numalloc = 0;
				}
				else
				{
					numalloc -= elen;
					if (*endnum > (i+1))
						memmove(&laarr[i], &laarr[i+1], 
							sizeof(long_ad) * (*endnum - (i+1)));
					i --;
					(*endnum) --;
				}
			}
			UDF_I_LENEXTENTS(inode) += numalloc << inode->i_sb->s_blocksize_bits;
		}
	}
}

static void udf_merge_extents(struct inode *inode,
	 long_ad laarr[EXTENT_MERGE_SIZE], int *endnum)
{
	int i;

	for (i=0; i<(*endnum-1); i++)
	{
		if ((laarr[i].extLength >> 30) == (laarr[i+1].extLength >> 30))
		{
			if (((laarr[i].extLength >> 30) == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)) ||
				((laarr[i+1].extLocation.logicalBlockNum - laarr[i].extLocation.logicalBlockNum) ==
				(((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
				inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits)))
			{
				if (((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
					(laarr[i+1].extLength & UDF_EXTENT_LENGTH_MASK) +
					inode->i_sb->s_blocksize - 1) & ~UDF_EXTENT_LENGTH_MASK)
				{
					laarr[i+1].extLength = (laarr[i+1].extLength -
						(laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
						UDF_EXTENT_LENGTH_MASK) & ~(inode->i_sb->s_blocksize-1);
					laarr[i].extLength = (laarr[i].extLength & UDF_EXTENT_FLAG_MASK) +
						(UDF_EXTENT_LENGTH_MASK + 1) - inode->i_sb->s_blocksize;
					laarr[i+1].extLocation.logicalBlockNum =
						laarr[i].extLocation.logicalBlockNum +
						((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) >>
							inode->i_sb->s_blocksize_bits);
				}
				else
				{
					laarr[i].extLength = laarr[i+1].extLength +
						(((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
						inode->i_sb->s_blocksize - 1) & ~(inode->i_sb->s_blocksize-1));
					if (*endnum > (i+2))
						memmove(&laarr[i+1], &laarr[i+2],
							sizeof(long_ad) * (*endnum - (i+2)));
					i --;
					(*endnum) --;
				}
			}
		}
		else if (((laarr[i].extLength >> 30) == (EXT_NOT_RECORDED_ALLOCATED >> 30)) &&
			((laarr[i+1].extLength >> 30) == (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30)))
		{
			udf_free_blocks(inode->i_sb, inode, laarr[i].extLocation, 0,
				((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
				inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits);
			laarr[i].extLocation.logicalBlockNum = 0;
			laarr[i].extLocation.partitionReferenceNum = 0;

			if (((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
				(laarr[i+1].extLength & UDF_EXTENT_LENGTH_MASK) +
				inode->i_sb->s_blocksize - 1) & ~UDF_EXTENT_LENGTH_MASK)
			{
				laarr[i+1].extLength = (laarr[i+1].extLength -
					(laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
					UDF_EXTENT_LENGTH_MASK) & ~(inode->i_sb->s_blocksize-1);
				laarr[i].extLength = (laarr[i].extLength & UDF_EXTENT_FLAG_MASK) +
					(UDF_EXTENT_LENGTH_MASK + 1) - inode->i_sb->s_blocksize;
			}
			else
			{
				laarr[i].extLength = laarr[i+1].extLength +
					(((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
					inode->i_sb->s_blocksize - 1) & ~(inode->i_sb->s_blocksize-1));
				if (*endnum > (i+2))
					memmove(&laarr[i+1], &laarr[i+2],
						sizeof(long_ad) * (*endnum - (i+2)));
				i --;
				(*endnum) --;
			}
		}
		else if ((laarr[i].extLength >> 30) == (EXT_NOT_RECORDED_ALLOCATED >> 30))
		{
			udf_free_blocks(inode->i_sb, inode, laarr[i].extLocation, 0,
				((laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) +
			       inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits);
			laarr[i].extLocation.logicalBlockNum = 0;
			laarr[i].extLocation.partitionReferenceNum = 0;
			laarr[i].extLength = (laarr[i].extLength & UDF_EXTENT_LENGTH_MASK) |
				EXT_NOT_RECORDED_NOT_ALLOCATED;
		}
	}
}

static void udf_update_extents(struct inode *inode,
	long_ad laarr[EXTENT_MERGE_SIZE], int startnum, int endnum,
	lb_addr pbloc, uint32_t pextoffset, struct buffer_head **pbh)
{
	int start = 0, i;
	lb_addr tmploc;
	uint32_t tmplen;

	if (startnum > endnum)
	{
		for (i=0; i<(startnum-endnum); i++)
		{
			udf_delete_aext(inode, pbloc, pextoffset, laarr[i].extLocation,
				laarr[i].extLength, *pbh);
		}
	}
	else if (startnum < endnum)
	{
		for (i=0; i<(endnum-startnum); i++)
		{
			udf_insert_aext(inode, pbloc, pextoffset, laarr[i].extLocation,
				laarr[i].extLength, *pbh);
			udf_next_aext(inode, &pbloc, &pextoffset, &laarr[i].extLocation,
				&laarr[i].extLength, pbh, 1);
			start ++;
		}
	}

	for (i=start; i<endnum; i++)
	{
		udf_next_aext(inode, &pbloc, &pextoffset, &tmploc, &tmplen, pbh, 0);
		udf_write_aext(inode, pbloc, &pextoffset, laarr[i].extLocation,
			laarr[i].extLength, *pbh, 1);
	}
}

struct buffer_head * udf_bread(struct inode * inode, int block,
	int create, int * err)
{
	struct buffer_head * bh = NULL;

	bh = udf_getblk(inode, block, create, err);
	if (!bh)
		return NULL;

	if (buffer_uptodate(bh))
		return bh;
	ll_rw_block(READ, 1, &bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;
	brelse(bh);
	*err = -EIO;
	return NULL;
}

void udf_truncate(struct inode * inode)
{
	int offset;
	int err;

	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
			S_ISLNK(inode->i_mode)))
		return;
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return;

	lock_kernel();
	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
	{
		if (inode->i_sb->s_blocksize < (udf_file_entry_alloc_offset(inode) +
			inode->i_size))
		{
			udf_expand_file_adinicb(inode, inode->i_size, &err);
			if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
			{
				inode->i_size = UDF_I_LENALLOC(inode);
				unlock_kernel();
				return;
			}
			else
				udf_truncate_extents(inode);
		}
		else
		{
			offset = inode->i_size & (inode->i_sb->s_blocksize - 1);
			memset(UDF_I_DATA(inode) + UDF_I_LENEATTR(inode) + offset, 0x00, inode->i_sb->s_blocksize - offset - udf_file_entry_alloc_offset(inode));
			UDF_I_LENALLOC(inode) = inode->i_size;
		}
	}
	else
	{
		block_truncate_page(inode->i_mapping, inode->i_size, udf_get_block);
		udf_truncate_extents(inode);
	}	

	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	if (IS_SYNC(inode))
		udf_sync_inode (inode);
	else
		mark_inode_dirty(inode);
	unlock_kernel();
}

/*
 * udf_read_inode
 *
 * PURPOSE
 *	Read an inode.
 *
 * DESCRIPTION
 *	This routine is called by iget() [which is called by udf_iget()]
 *      (clean_inode() will have been called first)
 *	when an inode is first read into memory.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 *
 * 12/19/98 dgb  Updated to fix size problems.
 */

void
udf_read_inode(struct inode *inode)
{
	memset(&UDF_I_LOCATION(inode), 0xFF, sizeof(lb_addr));
}

void
__udf_read_inode(struct inode *inode)
{
	struct buffer_head *bh = NULL;
	struct fileEntry *fe;
	uint16_t ident;

	/*
	 * Set defaults, but the inode is still incomplete!
	 * Note: get_new_inode() sets the following on a new inode:
	 *      i_sb = sb
	 *      i_no = ino
	 *      i_flags = sb->s_flags
	 *      i_state = 0
	 * clean_inode(): zero fills and sets
	 *      i_count = 1
	 *      i_nlink = 1
	 *      i_op = NULL;
	 */
	inode->i_blksize = PAGE_SIZE;

	bh = udf_read_ptagged(inode->i_sb, UDF_I_LOCATION(inode), 0, &ident);

	if (!bh)
	{
		printk(KERN_ERR "udf: udf_read_inode(ino %ld) failed !bh\n",
			inode->i_ino);
		make_bad_inode(inode);
		return;
	}

	if (ident != TAG_IDENT_FE && ident != TAG_IDENT_EFE &&
		ident != TAG_IDENT_USE)
	{
		printk(KERN_ERR "udf: udf_read_inode(ino %ld) failed ident=%d\n",
			inode->i_ino, ident);
		udf_release_data(bh);
		make_bad_inode(inode);
		return;
	}

	fe = (struct fileEntry *)bh->b_data;

	if (le16_to_cpu(fe->icbTag.strategyType) == 4096)
	{
		struct buffer_head *ibh = NULL, *nbh = NULL;
		struct indirectEntry *ie;

		ibh = udf_read_ptagged(inode->i_sb, UDF_I_LOCATION(inode), 1, &ident);
		if (ident == TAG_IDENT_IE)
		{
			if (ibh)
			{
				lb_addr loc;
				ie = (struct indirectEntry *)ibh->b_data;
	
				loc = lelb_to_cpu(ie->indirectICB.extLocation);
	
				if (ie->indirectICB.extLength && 
					(nbh = udf_read_ptagged(inode->i_sb, loc, 0, &ident)))
				{
					if (ident == TAG_IDENT_FE ||
						ident == TAG_IDENT_EFE)
					{
						memcpy(&UDF_I_LOCATION(inode), &loc, sizeof(lb_addr));
						udf_release_data(bh);
						udf_release_data(ibh);
						udf_release_data(nbh);
						__udf_read_inode(inode);
						return;
					}
					else
					{
						udf_release_data(nbh);
						udf_release_data(ibh);
					}
				}
				else
					udf_release_data(ibh);
			}
		}
		else
			udf_release_data(ibh);
	}
	else if (le16_to_cpu(fe->icbTag.strategyType) != 4)
	{
		printk(KERN_ERR "udf: unsupported strategy type: %d\n",
			le16_to_cpu(fe->icbTag.strategyType));
		udf_release_data(bh);
		make_bad_inode(inode);
		return;
	}
	udf_fill_inode(inode, bh);
	udf_release_data(bh);
}

static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)