lcnalloc.c

LINUX下读写NTFS分区的工具。 已经集成了通过LIBCONV库支持中文的代码。

					ntfs_log_debug("Start_vcn: %lld\n", 
						       start_vcn);
				}
				
				rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
				rl[rlpos].length = prev_run_len = 1;
				rlpos++;
			}
			
			ntfs_log_debug("RUN:   %-16lld %-16lld %-16lld\n", 
				       rl[rlpos - 1].vcn, rl[rlpos - 1].lcn, 
				       rl[rlpos - 1].length);
			/* Done? */
			if (!--clusters) {
				if (used_zone_pos)
					ntfs_cluster_update_zone_pos(vol, 
						search_zone, lcn + bmp_pos + 1 +
							NTFS_LCNALLOC_SKIP);
				goto done_ret;
			}
			
			lcn++;
		}
		
		if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback)) {
			err = errno;
			goto err_ret;
		}
		
		if (!used_zone_pos) {
			
			used_zone_pos = 1;
			
			if (search_zone == 1)
				zone_start = vol->mft_zone_pos;
			else if (search_zone == 2)
				zone_start = vol->data1_zone_pos;
			else
				zone_start = vol->data2_zone_pos;
			
			if (!zone_start || zone_start == vol->mft_zone_start ||
					zone_start == vol->mft_zone_end)
				pass = 2;
			bmp_pos = zone_start;
		} else
			bmp_pos += buf_size;
		
		if (bmp_pos < zone_end)
			continue;

zone_pass_done:
		ntfs_log_trace("Finished current zone pass(%i).\n", pass);
		if (pass == 1) {
			
			pass = 2;
			zone_end = zone_start;
			
			if (search_zone == 1)
				zone_start = vol->mft_zone_start;
			else if (search_zone == 2)
				zone_start = vol->mft_zone_end;
			else
				zone_start = 0;
			
			/* Sanity check. */
			if (zone_end < zone_start)
				zone_end = zone_start;
			
			bmp_pos = zone_start;
			
			continue;
		} 
		/* pass == 2 */
done_zones_check:
		done_zones |= search_zone;
		if (done_zones < 7) {
			ntfs_log_trace("Switching zone.\n");
			pass = 1;
			if (rlpos) {
				LCN tc = tc = rl[rlpos - 1].lcn + 
				      rl[rlpos - 1].length + NTFS_LCNALLOC_SKIP;
				
				if (used_zone_pos)
					ntfs_cluster_update_zone_pos(vol, 
						search_zone, tc);
			}
			
			switch (search_zone) {
			case 1:
				ntfs_log_trace("Zone switch: mft -> data1\n");
switch_to_data1_zone:		search_zone = 2;
				zone_start = vol->data1_zone_pos;
				zone_end = vol->nr_clusters;
				if (zone_start == vol->mft_zone_end)
					pass = 2;
				break;
			case 2:
				ntfs_log_trace("Zone switch: data1 -> data2\n");
				search_zone = 4;
				zone_start = vol->data2_zone_pos;
				zone_end = vol->mft_zone_start;
				if (!zone_start)
					pass = 2;
				break;
			case 4:
				if (!(done_zones & 2)) {
					ntfs_log_trace("data2 -> data1\n");
					goto switch_to_data1_zone;
				}
				ntfs_log_trace("Zone switch: data2 -> mft\n");
				search_zone = 1;
				zone_start = vol->mft_zone_pos;
				zone_end = vol->mft_zone_end;
				if (!zone_start == vol->mft_zone_start)
					pass = 2;
				break;
			}
			
			bmp_pos = zone_start;
			
			if (zone_start == zone_end) {
				ntfs_log_trace("Empty zone, skipped.\n");
				goto done_zones_check;
			}
			
			continue;
		}
		
		ntfs_log_trace("All zones are finished, no space on device.\n");
		err = ENOSPC;
		goto err_ret;
	}
done_ret:
	ntfs_log_debug("At done_ret.\n");
	/* Add runlist terminator element. */
	rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
	rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
	rl[rlpos].length = 0;
	if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback)) {
		err = errno;
		goto err_ret;
	}
done_err_ret:
	free(buf);
	if (err) {
		errno = err;
		ntfs_log_perror("Failed to allocate clusters");
		rl = NULL;
	}
out:	
	ntfs_log_leave("\n");
	return rl;

wb_err_ret:
	ntfs_log_trace("At wb_err_ret.\n");
	if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback))
		err = errno;
err_ret:
	ntfs_log_trace("At err_ret.\n");
	if (rl) {
		/* Add runlist terminator element. */
		rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
		rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
		rl[rlpos].length = 0;
		ntfs_debug_runlist_dump(rl);
		ntfs_cluster_free_from_rl(vol, rl);
		free(rl);
		rl = NULL;
	}
	goto done_err_ret;
}

/**
 * ntfs_cluster_free_from_rl - free clusters from runlist
 * @vol:	mounted ntfs volume on which to free the clusters
 * @rl:		runlist from which deallocate clusters
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
int ntfs_cluster_free_from_rl(ntfs_volume *vol, runlist *rl)
{
	s64 nr_freed = 0;
	int ret = -1;

	ntfs_log_trace("Entering.\n");

	for (; rl->length; rl++) {

		ntfs_log_trace("Dealloc lcn 0x%llx, len 0x%llx.\n",
			       (long long)rl->lcn, (long long)rl->length);

		if (rl->lcn >= 0) { 
			if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn, 
						  rl->length)) {
				ntfs_log_perror("Cluster deallocation failed "
					       "(%lld, %lld)",
						(long long)rl->lcn, 
						(long long)rl->length);
				goto out;
			}
			nr_freed += rl->length ; 
		}
	}

	ret = 0;
out:
	vol->free_clusters += nr_freed; 
	if (vol->free_clusters > vol->nr_clusters)
		ntfs_log_error("Too many free clusters (%lld > %lld)!",
			       (long long)vol->free_clusters, 
			       (long long)vol->nr_clusters);
	return ret;
}

/**
 * ntfs_cluster_free - free clusters on an ntfs volume
 * @vol:	mounted ntfs volume on which to free the clusters
 * @na:		attribute whose runlist describes the clusters to free
 * @start_vcn:	vcn in @rl at which to start freeing clusters
 * @count:	number of clusters to free or -1 for all clusters
 *
 * Free @count clusters starting at the cluster @start_vcn in the runlist
 * described by the attribute @na from the mounted ntfs volume @vol.
 *
 * If @count is -1, all clusters from @start_vcn to the end of the runlist
 * are deallocated.
 *
 * On success return the number of deallocated clusters (not counting sparse
 * clusters) and on error return -1 with errno set to the error code.
 */
int ntfs_cluster_free(ntfs_volume *vol, ntfs_attr *na, VCN start_vcn, s64 count)
{
	runlist *rl;
	s64 delta, to_free, nr_freed = 0;
	int ret = -1;

	if (!vol || !vol->lcnbmp_na || !na || start_vcn < 0 ||
			(count < 0 && count != -1)) {
		ntfs_log_trace("Invalid arguments!\n");
		errno = EINVAL;
		return -1;
	}
	
	ntfs_log_enter("Entering for inode 0x%llx, attr 0x%x, count 0x%llx, "
		       "vcn 0x%llx.\n", (unsigned long long)na->ni->mft_no,
		       na->type, (long long)count, (long long)start_vcn);

	rl = ntfs_attr_find_vcn(na, start_vcn);
	if (!rl) {
		if (errno == ENOENT)
			ret = 0;
		goto leave;
	}

	if (rl->lcn < 0 && rl->lcn != LCN_HOLE) {
		errno = EIO;
		ntfs_log_perror("%s: Unexpected lcn (%lld)", __FUNCTION__, 
				(long long)rl->lcn);
		goto leave;
	}

	/* Find the starting cluster inside the run that needs freeing. */
	delta = start_vcn - rl->vcn;

	/* The number of clusters in this run that need freeing. */
	to_free = rl->length - delta;
	if (count >= 0 && to_free > count)
		to_free = count;

	if (rl->lcn != LCN_HOLE) {
		/* Do the actual freeing of the clusters in this run. */
		if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn + delta,
					  to_free))
			goto leave;
		nr_freed = to_free;
	} 

	/* Go to the next run and adjust the number of clusters left to free. */
	++rl;
	if (count >= 0)
		count -= to_free;

	/*
	 * Loop over the remaining runs, using @count as a capping value, and
	 * free them.
	 */
	for (; rl->length && count != 0; ++rl) {
		// FIXME: Need to try ntfs_attr_map_runlist() for attribute
		//	  list support! (AIA)
		if (rl->lcn < 0 && rl->lcn != LCN_HOLE) {
			// FIXME: Eeek! We need rollback! (AIA)
			errno = EIO;
			ntfs_log_perror("%s: Invalid lcn (%lli)", 
					__FUNCTION__, (long long)rl->lcn);
			goto out;
		}

		/* The number of clusters in this run that need freeing. */
		to_free = rl->length;
		if (count >= 0 && to_free > count)
			to_free = count;

		if (rl->lcn != LCN_HOLE) {
			if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn,
					to_free)) {
				// FIXME: Eeek! We need rollback! (AIA)
				ntfs_log_perror("%s: Clearing bitmap run failed",
						__FUNCTION__);
				goto out;
			}
			nr_freed += to_free;
		}

		if (count >= 0)
			count -= to_free;
	}

	if (count != -1 && count != 0) {
		// FIXME: Eeek! BUG()
		errno = EIO;
		ntfs_log_perror("%s: count still not zero (%lld)", __FUNCTION__,
			       (long long)count);
		goto out;
	}

	ret = nr_freed;
out:
	vol->free_clusters += nr_freed ; 
	if (vol->free_clusters > vol->nr_clusters)
		ntfs_log_error("Too many free clusters (%lld > %lld)!",
			       (long long)vol->free_clusters, 
			       (long long)vol->nr_clusters);
leave:	
	ntfs_log_leave("\n");
	return ret;
}