super.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

			search_zone = 4;
		}
	} else /* if (zone == MFT_ZONE) */ {
		zone_end = vol->mft_zone_end;
		search_zone = 1;
	}
	/*
	 * buf_pos is the current bit position inside the bitmap. We use
	 * initial_location to determine whether or not to do a zone switch.
	 */
	buf_pos = initial_location = zone_start;
	/* Loop until all clusters are allocated, i.e. clusters == 0. */
	clusters = *count;
	rlpos = rlsize = 0;
	if (*count <= 0) {
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): *count <= 0, "
				"returning -EINVAL.\n");
		err = -EINVAL;
		goto err_ret;
	}
	while (1) {
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Start of outer while "
				"loop: done_zones = 0x%x, search_zone = %i, "
				"pass = %i, zone_start = 0x%x, zone_end = "
				"0x%x, initial_location = 0x%x, buf_pos = "
				"0x%x, rlpos = %i, rlsize = %i.\n",
				done_zones, search_zone, pass, zone_start,
				zone_end, initial_location, buf_pos, rlpos,
				rlsize);
		/* Loop until we run out of free clusters. */
		io.param = buf;
		io.size = PAGE_SIZE;
		io.do_read = 1;
		last_read_pos = buf_pos >> 3;
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): last_read_pos = "
				"0x%x.\n", last_read_pos);
		err = ntfs_readwrite_attr(vol->bitmap, data, last_read_pos,
				&io);
		if (err) {
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
					"ntfs_read_attr failed with error "
					"code %i, going to err_ret.\n", -err);
			goto err_ret;
		}
		if (!io.size) {
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): !io.size, "
					"going to zone_pass_done.\n");
			goto zone_pass_done;
		}
		buf_size = io.size << 3;
		lcn = buf_pos & 7;
		buf_pos &= ~7;
		need_writeback = 0;
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Before inner while "
				"loop: buf_size = 0x%x, lcn = 0x%x, buf_pos = "
				"0x%x, need_writeback = %i.\n", buf_size, lcn,
				buf_pos, need_writeback);
		while (lcn < buf_size && lcn + buf_pos < zone_end) {
			byte = buf + (lcn >> 3);
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): In inner "
					"while loop: buf_size = 0x%x, lcn = "
					"0x%x, buf_pos = 0x%x, need_writeback "
					"= %i, byte ofs = 0x%x, *byte = "
					"0x%x.\n", buf_size, lcn, buf_pos,
					need_writeback, lcn >> 3, *byte);
			/* Skip full bytes. */
			if (*byte == 0xff) {
				lcn += 8;
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"continuing while loop 1.\n");
				continue;
			}
			bit = 1 << (lcn & 7);
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): bit = %i.\n",
					bit);
			/* If the bit is already set, go onto the next one. */
			if (*byte & bit) {
				lcn++;
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"continuing while loop 2.\n");
				continue;
			}
			/* Allocate the bitmap bit. */
			*byte |= bit;
			/* We need to write this bitmap buffer back to disk! */
			need_writeback = 1;
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): *byte = "
					"0x%x, need_writeback = %i.\n", *byte,
					need_writeback);
			/* Reallocate memory if necessary. */
			if ((rlpos + 2) * sizeof(ntfs_runlist) >= rlsize) {
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Reallocating space.\n");
				/* Setup first free bit return value. */
				if (!rl2) {
					*location = lcn + buf_pos;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): *location = "
							"0x%x.\n", *location);
				}
				rlsize += PAGE_SIZE;
				rlt = ntfs_vmalloc(rlsize);
				if (!rlt) {
					err = -ENOMEM;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Failed to "
							"allocate memory, "
							"returning -ENOMEM, "
							"going to "
							"wb_err_ret.\n");
					goto wb_err_ret;
				}
				if (rl2) {
					ntfs_memcpy(rlt, rl2, rlsize -
							PAGE_SIZE);
					ntfs_vfree(rl2);
				}
				rl2 = rlt;
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Reallocated memory, rlsize = "
						"0x%x.\n", rlsize);
			}
			/*
			 * Coalesce with previous run if adjacent LCNs.
			 * Otherwise, append a new run.
			 */
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Adding run "
					"(lcn 0x%x, len 0x%x), prev_lcn = "
					"0x%x, lcn = 0x%x, buf_pos = 0x%x, "
					"prev_run_len = 0x%x, rlpos = %i.\n",
					lcn + buf_pos, 1, prev_lcn, lcn,
					buf_pos, prev_run_len, rlpos);
			if (prev_lcn == lcn + buf_pos - prev_run_len && rlpos) {
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Coalescing to run (lcn 0x%x, "
						"len 0x%x).\n",
						rl2[rlpos - 1].lcn,
						rl2[rlpos - 1].len);
				rl2[rlpos - 1].len = ++prev_run_len;
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Run now (lcn 0x%x, len 0x%x), "
						"prev_run_len = 0x%x.\n",
						rl2[rlpos - 1].lcn,
						rl2[rlpos - 1].len,
						prev_run_len);
			} else {
				if (rlpos)
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Adding new run, "
							"(previous run lcn "
							"0x%x, len 0x%x).\n",
							rl2[rlpos - 1].lcn,
							rl2[rlpos - 1].len);
				else
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Adding new run, "
							"is first run.\n");
				rl2[rlpos].lcn = prev_lcn = lcn + buf_pos;
				rl2[rlpos].len = prev_run_len =
						(ntfs_cluster_t)1;
				
				rlpos++;
			}
			/* Done? */
			if (!--clusters) {
				ntfs_cluster_t tc;
				/*
				 * Update the current zone position. Positions
				 * of already scanned zones have been updated
				 * during the respective zone switches.
				 */
				tc = lcn + buf_pos + 1;
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Done. Updating current zone "
						"position, tc = 0x%x, "
						"search_zone = %i.\n", tc,
						search_zone);
				switch (search_zone) {
				case 1:
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Before checks, "
							"vol->mft_zone_pos = "
							"0x%x.\n",
							vol->mft_zone_pos);
					if (tc >= vol->mft_zone_end) {
						vol->mft_zone_pos =
								vol->mft_lcn;
						if (!vol->mft_zone_end)
							vol->mft_zone_pos =
							     (ntfs_cluster_t)0;
					} else if ((initial_location >=
							vol->mft_zone_pos ||
							tc > vol->mft_zone_pos)
							&& tc >= vol->mft_lcn)
						vol->mft_zone_pos = tc;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): After checks, "
							"vol->mft_zone_pos = "
							"0x%x.\n",
							vol->mft_zone_pos);
					break;
				case 2:
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Before checks, "
							"vol->data1_zone_pos = "
							"0x%x.\n",
							vol->data1_zone_pos);
					if (tc >= vol->nr_clusters)
						vol->data1_zone_pos =
							     vol->mft_zone_end;
					else if ((initial_location >=
						    vol->data1_zone_pos ||
						    tc > vol->data1_zone_pos)
						    && tc >= vol->mft_zone_end)
						vol->data1_zone_pos = tc;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): After checks, "
							"vol->data1_zone_pos = "
							"0x%x.\n",
							vol->data1_zone_pos);
					break;
				case 4:
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Before checks, "
							"vol->data2_zone_pos = "
							"0x%x.\n",
							vol->data2_zone_pos);
					if (tc >= vol->mft_zone_start)
						vol->data2_zone_pos =
							(ntfs_cluster_t)0;
					else if (initial_location >=
						      vol->data2_zone_pos ||
						      tc > vol->data2_zone_pos)
						vol->data2_zone_pos = tc;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): After checks, "
							"vol->data2_zone_pos = "
							"0x%x.\n",
							vol->data2_zone_pos);
					break;
				default:
					BUG();
				}
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Going to done_ret.\n");
				goto done_ret;
			}
			lcn++;
		}
		buf_pos += buf_size;
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): After inner while "
				"loop: buf_size = 0x%x, lcn = 0x%x, buf_pos = "
				"0x%x, need_writeback = %i.\n", buf_size, lcn,
				buf_pos, need_writeback);
		if (need_writeback) {
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Writing "
					"back.\n");
			need_writeback = 0;
			io.param = buf;
			io.do_read = 0;
			err = ntfs_readwrite_attr(vol->bitmap, data,
					last_read_pos, &io);
			if (err) {
				ntfs_error(__FUNCTION__ "(): Bitmap writeback "
						"failed in read next buffer "
						"code path with error code "
						"%i.\n", -err);
				goto err_ret;
			}
		}
		if (buf_pos < zone_end) {
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Continuing "
					"outer while loop, buf_pos = 0x%x, "
					"zone_end = 0x%x.\n", buf_pos,
					zone_end);
			continue;
		}
zone_pass_done:	/* Finished with the current zone pass. */
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): At zone_pass_done, "
				"pass = %i.\n", pass);
		if (pass == 1) {
			/*
			 * Now do pass 2, scanning the first part of the zone
			 * we omitted in pass 1.
			 */
			pass = 2;
			zone_end = zone_start;
			switch (search_zone) {
			case 1: /* mft_zone */
				zone_start = vol->mft_zone_start;
				break;
			case 2: /* data1_zone */
				zone_start = vol->mft_zone_end;
				break;
			case 4: /* data2_zone */
				zone_start = (ntfs_cluster_t)0;
				break;
			default:
				BUG();
			}
			/* Sanity check. */
			if (zone_end < zone_start)
				zone_end = zone_start;
			buf_pos = zone_start;
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Continuing "
					"outer while loop, pass = 2, "
					"zone_start = 0x%x, zone_end = 0x%x, "
					"buf_pos = 0x%x.\n");
			continue;
		} /* pass == 2 */
done_zones_check:
		ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): At done_zones_check, "
				"search_zone = %i, done_zones before = 0x%x, "
				"done_zones after = 0x%x.\n",
				search_zone, done_zones, done_zones |
				search_zone);
		done_zones |= search_zone;
		if (done_zones < 7) {
			ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): Switching "
					"zone.\n");
			/* Now switch to the next zone we haven't done yet. */
			pass = 1;
			switch (search_zone) {
			case 1:
				ntfs_debug(DEBUG_OTHER, __FUNCTION__ "(): "
						"Switching from mft zone to "
						"data1 zone.\n");
				/* Update mft zone position. */
				if (rlpos) {
					ntfs_cluster_t tc;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): Before checks, "
							"vol->mft_zone_pos = "
							"0x%x.\n",
							vol->mft_zone_pos);
					tc = rl2[rlpos - 1].lcn +
							rl2[rlpos - 1].len;
					if (tc >= vol->mft_zone_end) {
						vol->mft_zone_pos =
								vol->mft_lcn;
						if (!vol->mft_zone_end)
							vol->mft_zone_pos =
							     (ntfs_cluster_t)0;
					} else if ((initial_location >=
							vol->mft_zone_pos ||
							tc > vol->mft_zone_pos)
							&& tc >= vol->mft_lcn)
						vol->mft_zone_pos = tc;
					ntfs_debug(DEBUG_OTHER, __FUNCTION__
							"(): After checks, "
							"vol->mft_zone_pos = "
							"0x%x.\n",
							vol->mft_zone_pos);
				}