ftape-eof.c

arm平台上的uclinux系统全部源代码

							++sector_nr;
							mask >>= 1;
						}
						if (sector_nr >= 29) {
							if (++segment >= ftape_last_segment.id) {
								TRACEx1(5, "segment out of range: %d", segment);
								result = -EIO;
								break;
							}
							mask = get_bad_sector_entry(segment);
							sector_nr = 0;
						}
					} while (mask & 1);
					++sector_nr;	/* point to good sector */
					mask >>= 1;
				} while (--sector);
				if (result >= 0) {
					TRACEx2(5, "writing filemark %d/%d", segment, sector_nr);
					put_file_mark_in_map(segment, sector_nr);
					++segment;	/* next segment */
					sector_nr = 0;
					sector = 1;	/* first sector */
				}
			}
		}
	} else {
		result = -EPERM;
	}
	TRACE_EXIT;
	return result;
}

int ftape_erase(void)
{
	TRACE_FUN(5, "ftape_erase");
	int result = 0;
	int i;
	unsigned long now = 0;
	byte *buffer = deblock_buffer;

	if (write_protected) {
		result = -EROFS;
	} else {
		result = read_header_segment(buffer);
		if (result >= 0) {
			/*  Copy entries from bad-sector-log into bad-sector-map
			 */
			TRACEx1(5, "old label: `%s'", (char *) (buffer + 30));
			if (!ftape_validate_label((char *) &buffer[30])) {
				TRACE(5, "invalid label, overwriting with new");
				memset(buffer + 30, 0, 44);
				memcpy(buffer + 30, linux_tape_label, strlen(linux_tape_label));
				buffer[30 + strlen(linux_tape_label)] = '2';
				TRACEx1(5, "new label: `%s'", (char *) (buffer + 30));
				PUT4(buffer, 74, now);
				if (format_code != 4) {
					for (i = 0; i < nr_of_eof_marks; ++i) {
						unsigned failing_segment = eof_map[i].mark.segment;

						if (!valid_segment_no(failing_segment)) {
							TRACEi(4, "bad entry in failed sector log:", failing_segment);
						} else {
							put_bad_sector_entry(failing_segment, EMPTY_SEGMENT);
							TRACEx2(4, "moved entry %d from failed sector log (%d)",
								i, failing_segment);
						}
					}
				}
			}
			/*  Clear failed sector log: remove all tape marks
			 */
			failed_sector_log_changed = 1;
			memset(eof_map, 0, sizeof(eof_map));
			nr_of_eof_marks = 0;
			ftape_fmt_version = max_fmt_version;
#if 0
			fix_tape(buffer);	/* see ftape-bsm.c ! */
#endif
			result = ftape_update_header_segments(buffer, 1);
			prevent_flush();	/* prevent flush_buffers writing file marks */
			reset_eof_list();
		}
	}
	TRACE_EXIT;
	return result;
}

void extract_file_marks(byte * address)
{
	TRACE_FUN(8, "extract_file_marks");
	int i;

	if (format_code == 4) {
		byte *end;
		byte *start = find_end_of_bsm_list(address + 256,
					     address + 29 * SECTOR_SIZE);

		memset(eof_map, 0, sizeof(eof_map));
		nr_of_eof_marks = 0;
		if (start) {
			start += 3;	/* skip end of list mark */
			end = find_end_of_eof_list(start, address + 29 * SECTOR_SIZE);
			if (end && end - start <= sizeof(eof_map)) {
				nr_of_eof_marks = (end - start) / sizeof(unsigned long);
				memcpy(eof_map, start, end - start);
			} else {
				TRACE(1, "File Mark List is too long or damaged !");
			}
		} else {
			TRACE(1, "Bad Sector List is too long or damaged !");
		}
	} else {
		memcpy(eof_map, address + 256, sizeof(eof_map));
		nr_of_eof_marks = GET2(address, 144);
	}
	TRACEi(4, "number of file marks:", nr_of_eof_marks);
	if (ftape_fmt_version == 1) {
		TRACE(-1, "swapping version 1 fields");
		/*  version 1 format uses swapped sector and segment fields, correct that !
		 */
		for (i = 0; i < nr_of_eof_marks; ++i) {
			unsigned short tmp = eof_map[i].mark.segment;
			eof_map[i].mark.segment = eof_map[i].mark.sector;
			eof_map[i].mark.sector = tmp;
		}
	}
	for (i = 0; i < nr_of_eof_marks; ++i) {
		TRACEx2(4, "eof mark: %5d/%2d",
			eof_map[i].mark.segment, eof_map[i].mark.sector);
	}
	reset_eof_list();
	TRACE_EXIT;
}

int update_failed_sector_log(byte * buffer)
{
	TRACE_FUN(8, "update_failed_sector_log");

	if (ftape_fmt_version != 0 && failed_sector_log_changed) {
		if (ftape_fmt_version == 1) {
			TRACE(-1, "upgrading version 1 format to version 2");
			/*  version 1 will be upgraded to version 2 when written.
			 */
			buffer[30 + strlen(linux_tape_label)] = '2';
			ftape_fmt_version = 2;
			TRACEx1(-1, "new tape label = \"%s\"", &buffer[30]);
		}
		if (format_code == 4) {
			byte *dest = find_end_of_bsm_list(buffer + 256,
					  buffer + 29 * SECTOR_SIZE) + 3;

			if (dest) {
				TRACEx2(4, "eof_map at byte offset %6d, size %d",
					dest - buffer - 256, nr_of_eof_marks * sizeof(unsigned long));
				memcpy(dest, eof_map, nr_of_eof_marks * sizeof(unsigned long));
				PUT4(dest, nr_of_eof_marks * sizeof(unsigned long), 0);
			}
		} else {
			memcpy(buffer + 256, eof_map, sizeof(eof_map));
			PUT2(buffer, 144, nr_of_eof_marks);
		}
		failed_sector_log_changed = 0;
		return 1;
	}
	TRACE_EXIT;
	return 0;
}

int ftape_seek_eom(void)
{
	TRACE_FUN(5, "ftape_seek_eom");
	int result = 0;
	unsigned eom;

	if (first_data_segment == -1) {
		result = read_header_segment(deblock_buffer);
	}
	if (result >= 0 && ftape_fmt_version != 0) {
		eom = first_data_segment;
		eof_index = 0;
		eof_mark_ptr = &eof_map[0].mark;
		/*  If fresh tape, count should be zero but we don't
		 *  want to worry about the case it's one.
		 */
		for (eof_index = 1, eof_mark_ptr = &eof_map[1].mark;
		     eof_index < nr_of_eof_marks; ++eof_index, ++eof_mark_ptr) {
			/*  The eom is recorded as two eof marks in succeeding segments
			 *  where the second one is always at segment number 1.
			 */
			if (eof_mark_ptr->sector == 1) {
				if (eof_mark_ptr->segment == (eof_mark_ptr - 1)->segment + 1) {
					eom = eof_mark_ptr->segment;
					break;
				}
			}
		}
		ftape_seg_pos = eom;
		TRACEx1(5, "eom found at segment %d", eom);
	} else {
		TRACE(5, "Couldn't get eof mark table");
		result = -EIO;
	}
	TRACE_EXIT;
	return result;
}

int ftape_seek_eof(unsigned count)
{
	TRACE_FUN(5, "ftape_seek_eof");
	int result = 0;
	enum {
		not = 0, begin, end
	} bad_seek = not;

	if (first_data_segment == -1) {
		result = read_header_segment(deblock_buffer);
	}
	TRACEx1(5, "tape positioned at segment %d", ftape_seg_pos);
	if (ftape_fmt_version == 0) {
		result = -1;
	}
	if (result >= 0 && count != 0) {
		for (eof_index = 0; eof_index <= nr_of_eof_marks; ++eof_index) {
			if (eof_index == nr_of_eof_marks ||	/* start seeking after last mark */
			    ftape_seg_pos <= eof_map[eof_index].mark.segment) {
				eof_index += count;
				if (eof_index < 1) {	/* begin of tape */
					ftape_seg_pos = first_data_segment;
					if (eof_index < 0) {	/* `before' begin of tape */
						eof_index = 0;
						bad_seek = begin;
					}
				} else if (eof_index >= nr_of_eof_marks) {	/* `after' end of tape */
					ftape_seg_pos = segments_per_track * tracks_per_tape;
					if (eof_index > nr_of_eof_marks) {
						eof_index = nr_of_eof_marks;
						bad_seek = end;
					}
				} else {	/* after requested file mark */
					ftape_seg_pos = eof_map[eof_index - 1].mark.segment + 1;
				}
				eof_mark_ptr = &eof_map[eof_index].mark;
				break;
			}
		}
	}
	if (result < 0) {
		TRACE(5, "Couldn't get eof mark table");
		result = -EIO;
	} else if (bad_seek != not) {
		TRACEx1(1, "seek reached %s of tape",
			(bad_seek == begin) ? "begin" : "end");
		result = -EIO;
	} else {
		TRACEx1(5, "tape repositioned to segment %d", ftape_seg_pos);
	}
	TRACE_EXIT;
	return result;
}

int ftape_file_no(daddr_t * f_no, daddr_t * b_no)
{
	TRACE_FUN(5, "ftape_file_no");
	int result = 0;
	int i;

	*f_no = eof_index;
	*b_no = ftape_seg_pos;
	TRACEi(4, "number of file marks:", nr_of_eof_marks);
	for (i = 0; i < nr_of_eof_marks; ++i) {
		TRACEx2(4, "eof mark: %5d/%2d",
			eof_map[i].mark.segment, eof_map[i].mark.sector);
	}
	TRACE_EXIT;
	return result;
}