/* * Copyright (C) 1993-1995 Bas Laarhoven. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. $Source: /home/bas/distr/ftape-2.03b/RCS/ftape-read.c,v $ $Author: bas $ * $Revision: 1.30 $ $Date: 1995/05/27 08:54:21 $ $State: Beta $ * * This file contains the reading code * for the QIC-117 floppy-tape driver for Linux. */ #include #include #include #include #include #include "tracing.h" #include "ftape-read.h" #include "qic117.h" #include "ftape-io.h" #include "ftape-ctl.h" #include "ftape-rw.h" #include "ftape-write.h" #include "ftape-eof.h" #include "ecc.h" #include "ftape-bsm.h" /* Global vars. */ /* Local vars. */ int buf_pos_rd = 0; int buf_len_rd = 0; void ftape_zap_read_buffers(void) { int i; for (i = 0; i < NR_BUFFERS; ++i) { /* * changed to "fit" with dynamic allocation of tape_buffer. --khp */ buffer[i].address = tape_buffer[i]; buffer[i].status = waiting; buffer[i].bytes = 0; buffer[i].skip = 0; buffer[i].retry = 0; } buf_len_rd = 0; buf_pos_rd = 0; eof_mark = 0; ftape_state = idle; } static unsigned long convert_sector_map(buffer_struct * buff) { TRACE_FUN(8, "convert_sector_map"); int i = 0; unsigned long bad_map = get_bad_sector_entry(buff->segment_id); unsigned long src_map = buff->soft_error_map | buff->hard_error_map; unsigned long dst_map = 0; if (bad_map || src_map) { TRACEx1(5, "bad_map = 0x%08lx", bad_map); TRACEx1(5, "src_map = 0x%08lx", src_map); } while (bad_map) { while ((bad_map & 1) == 0) { if (src_map & 1) { dst_map |= (1 << i); } src_map >>= 1; bad_map >>= 1; ++i; } /* (bad_map & 1) == 1 */ src_map >>= 1; bad_map >>= 1; } if (src_map) { dst_map |= (src_map << i); } if (dst_map) { TRACEx1(5, "dst_map = 0x%08lx", dst_map); } TRACE_EXIT; return dst_map; } int correct_and_copy(unsigned int tail, byte * destination) { TRACE_FUN(8, "correct_and_copy"); struct memory_segment mseg; int result; BAD_SECTOR read_bad; mseg.read_bad = convert_sector_map(&buffer[tail]); mseg.marked_bad = 0; /* not used... */ mseg.blocks = buffer[tail].bytes / SECTOR_SIZE; mseg.data = buffer[tail].address; /* If there are no data sectors we can skip this segment. */ if (mseg.blocks <= 3) { TRACE(4, "empty segment"); TRACE_EXIT; return 0; } read_bad = mseg.read_bad; history.crc_errors += count_ones(read_bad); result = ecc_correct_data(&mseg); if (read_bad != 0 || mseg.corrected != 0) { TRACElx(4, "crc error map:", read_bad); TRACElx(4, "corrected map:", mseg.corrected); history.corrected += count_ones(mseg.corrected); } if (result == ECC_CORRECTED || result == ECC_OK) { if (result == ECC_CORRECTED) { TRACEi(3, "ecc corrected segment:", buffer[tail].segment_id); } memcpy(destination, mseg.data, (mseg.blocks - 3) * SECTOR_SIZE); if ((read_bad ^ mseg.corrected) & mseg.corrected) { /* sectors corrected without crc errors set */ history.crc_failures++; } TRACE_EXIT; return (mseg.blocks - 3) * SECTOR_SIZE; } else { TRACEi(1, "ecc failure on segment", buffer[tail].segment_id); history.ecc_failures++; TRACE_EXIT; return -EAGAIN; /* should retry */ } TRACE_EXIT; return 0; } /* Read given segment into buffer at address. */ int read_segment(unsigned segment_id, byte * address, int *eof_mark, int read_ahead) { TRACE_FUN(5, "read_segment"); int read_done = 0; int result = 0; int bytes_read = 0; int retry = 0; TRACEi(5, "segment_id =", segment_id); if (ftape_state != reading) { if (ftape_state == writing) { ftape_flush_buffers(); /* flush write buffer */ TRACE(5, "calling ftape_abort_operation"); result = ftape_abort_operation(); if (result < 0) { TRACE(1, "ftape_abort_operation failed"); TRACE_EXIT; return -EIO; } } else { /* clear remaining read buffers */ ftape_zap_read_buffers(); } ftape_state = reading; } if (segment_id >= segments_per_track * tracks_per_tape) { TRACE(5, "reading past end of tape"); TRACE_EXIT; return -ENOSPC; } for (;;) { /* Search all full buffers for the first matching the wanted segment. * Clear other buffers on the fly. */ while (!read_done && buffer[tail].status == done) { if (buffer[tail].segment_id == segment_id) { unsigned eof_sector; unsigned sector_count = 0; unsigned long bsm = get_bad_sector_entry(segment_id); int i; /* If out buffer is already full, return its contents. */ if (buffer[tail].deleted) { TRACEi(5, "found segment in cache :", segment_id); TRACE_EXIT; /* Return a value that read_header_segment understands. * As this should only occur when searching for the header * segments it shouldn't be misinterpreted elsewhere. */ return 0; } TRACEi(5, "found segment in cache :", segment_id); eof_sector = check_for_eof(segment_id); if (eof_sector > 0) { TRACEi(5, "end of file mark in sector:", eof_sector); for (i = 1; i < eof_sector; ++i) { if ((bsm & 1) == 0) { ++sector_count; } bsm >>= 1; } *eof_mark = 1; } if (eof_sector != 1) { /* not found or gt 1 */ result = correct_and_copy(tail, address); TRACEi(5, "segment contains (bytes) :", result); if (result < 0) { if (result != -EAGAIN) { TRACE_EXIT; return result; } /* keep read_done == 0, will trigger ftape_abort_operation * because reading wrong segment. */ TRACE(1, "ecc failed, retry"); ++retry; } else { read_done = 1; } } else { read_done = 1; } if (eof_sector > 0) { bytes_read = sector_count * SECTOR_SIZE; TRACEi(5, "partial read count:", bytes_read); } else { bytes_read = result; } } else { TRACEi(5, "zapping segment in cache :", buffer[tail].segment_id); } buffer[tail].status = waiting; next_buffer(&tail); } if (!read_done && buffer[tail].status == reading) { if (buffer[tail].segment_id == segment_id) { int result = wait_segment(reading); if (result < 0) { if (result == -EINTR) { TRACE_EXIT; return result; } TRACE(1, "wait_segment failed while reading"); ftape_abort_operation(); } } else { /* We're reading the wrong segment, stop runner. */ ftape_abort_operation(); } } /* if just passed the last segment on a track, wait for BOT or EOT mark. */ if (runner_status == logical_eot) { int status; result = ftape_ready_wait(timeout.seek, &status); if (result < 0) { TRACE(1, "ftape_ready_wait waiting for eot/bot failed"); } if ((status & (QIC_STATUS_AT_BOT | QIC_STATUS_AT_EOT)) == 0) { TRACE(1, "eot/bot not reached"); } runner_status = end_of_tape; } /* should runner stop ? */ if (runner_status == aborting || runner_status == buffer_overrun || runner_status == end_of_tape) { if (runner_status != end_of_tape && !(runner_status == aborting && !tape_running)) { ftape_dumb_stop(); } if (runner_status == aborting) { if (buffer[head].status == reading || buffer[head].status == error) { if (buffer[head].status == error) { history.defects += count_ones(buffer[head].hard_error_map); } buffer[head].status = waiting; } } runner_status = idle; /* aborted ? */ } /* If segment to read is empty, do not start runner for it, * but wait for next read call. */ if (get_bad_sector_entry(segment_id) == EMPTY_SEGMENT) { bytes_read = 0; /* flag empty segment */ read_done = 1; } /* Allow escape from this loop on signal ! */ if (current->signal & _DONT_BLOCK) { TRACE(2, "interrupted by non-blockable signal"); TRACE_EXIT; return -EINTR; } /* If we got a segment: quit, or else retry up to limit. */ if (read_done) { break; } if (retry > RETRIES_ON_ECC_ERROR) { history.defects++; TRACE(1, "too many retries on ecc failure"); TRACE_EXIT; return -ENODATA; } /* Now at least one buffer is empty ! * Restart runner & tape if needed. */ TRACEx3(8, "head: %d, tail: %d, runner_status: %d", head, tail, runner_status); TRACEx2(8, "buffer[].status, [head]: %d, [tail]: %d", buffer[head].status, buffer[tail].status); if (buffer[tail].status == waiting) { setup_new_segment(&buffer[head], segment_id, -1); if (!read_ahead) { buffer[head].next_segment = 0; /* disable read-ahead */ } calc_next_cluster(&buffer[head]); if (runner_status == idle) { result = ftape_start_tape(segment_id, buffer[head].sector_offset); if (result < 0) { TRACEx1(1, "Error: segment %d unreachable", segment_id); TRACE_EXIT; return result; } runner_status = running; } buffer[head].status = reading; setup_fdc_and_dma(&buffer[head], FDC_READ); } } if (read_done) { TRACE_EXIT; return bytes_read; } else { TRACE(1, "too many retries"); TRACE_EXIT; return -EIO; } } int read_header_segment(byte * address) { TRACE_FUN(5, "read_header_segment"); int i; int result; int header_segment = -1; unsigned int max_floppy_side; unsigned int max_floppy_track; unsigned int max_floppy_sector; int first_failed = 0; int status; int new_tape_len; result = ftape_report_drive_status(&status); if (result < 0) { TRACE(1, "error: error_status or report failure"); TRACE_EXIT; return -EIO; } TRACE(5, "reading..."); ftape_last_segment.id = 68; /* will allow us to read the header ! */ /* We're looking for the first header segment. * A header segment cannot contain bad sectors, therefor at the * tape start, segments with bad sectors are (according to QIC-40/80) * written with deleted data marks and must be skipped. */ used_header_segment = -1; result = 0; for (header_segment = 0; header_segment < ftape_last_segment.id && result == 0; ++header_segment) { /* Set no read-ahead, the isr will force read-ahead whenever * it encounters deleted data ! */ result = read_segment(header_segment, address, &status, 0); if (result < 0 && !first_failed) { TRACE(1, "header segment damaged, trying backup"); first_failed = 1; result = 0; /* force read of next (backup) segment */ } } if (result < 0 || header_segment >= ftape_last_segment.id) { TRACE(1, "no readable header segment found"); TRACE_EXIT; return -EIO; } result = ftape_abort_operation(); if (result < 0) { TRACE(1, "ftape_abort_operation failed"); TRACE_EXIT; return -EIO; } if (GET4(address, 0) != 0xaa55aa55) { TRACE(1, "wrong signature in header segment"); TRACE_EXIT; return -EIO; } header_segment_1 = GET2(address, 6); header_segment_2 = GET2(address, 8); TRACEx2(2, "header segments are %d and %d", header_segment_1, header_segment_2); used_header_segment = (first_failed) ? header_segment_2 : header_segment_1; /* Verify tape parameters... * QIC-40/80 spec: tape_parameters: * * segments-per-track segments_per_track * tracks-per-cartridge tracks_per_tape * max-floppy-side (segments_per_track * * tracks_per_tape - 1) / * segments_per_head * max-floppy-track segments_per_head / * segments_per_cylinder - 1 * max-floppy-sector segments_per_cylinder * * SECTORS_PER_SEGMENT */ format_code = (format_type) * (address + 4); segments_per_track = GET2(address, 24); tracks_per_tape = *(address + 26); max_floppy_side = *(address + 27); max_floppy_track = *(address + 28); max_floppy_sector = *(address + 29); TRACEx6(4, "(fmt/spt/tpc/fhm/ftm/fsm) = %d/%d/%d/%d/%d/%d", format_code, segments_per_track, tracks_per_tape, max_floppy_side, max_floppy_track, max_floppy_sector); new_tape_len = tape_len; switch (format_code) { case fmt_425ft: new_tape_len = 425; break; case fmt_normal: if (tape_len == 0) { /* otherwise 307 ft */ new_tape_len = 205; } break; case fmt_1100ft: new_tape_len = 1100; break; case fmt_wide:{ int segments_per_1000_inch = 1; /* non-zero default for switch */ switch (qic_std) { case QIC_TAPE_QIC40: segments_per_1000_inch = 332; break; case QIC_TAPE_QIC80: segments_per_1000_inch = 488; break; case QIC_TAPE_QIC3010: segments_per_1000_inch = 730; break; case QIC_TAPE_QIC3020: segments_per_1000_inch = 1430; break; } new_tape_len = (1000 * segments_per_track + (segments_per_1000_inch - 1)) / segments_per_1000_inch; break; } default: TRACE(1, "unknown tape format, please report !"); TRACE_EXIT; return -EIO; } if (new_tape_len != tape_len) { tape_len = new_tape_len; TRACEx1(1, "calculated tape length is %d ft", tape_len); ftape_calc_timeouts(); } if (segments_per_track == 0 && tracks_per_tape == 0 && max_floppy_side == 0 && max_floppy_track == 0 && max_floppy_sector == 0) { /* QIC-40 Rev E and earlier has no values in the header. */ segments_per_track = 68; tracks_per_tape = 20; max_floppy_side = 1; max_floppy_track = 169; max_floppy_sector = 128; } /* This test will compensate for the wrong parameter on tapes * formatted by Conner software. */ if (segments_per_track == 150 && tracks_per_tape == 28 && max_floppy_side == 7 && max_floppy_track == 149 && max_floppy_sector == 128) { TRACE(-1, "the famous CONNER bug: max_floppy_side off by one !"); max_floppy_side = 6; } /* This test will compensate for the wrong parameter on tapes * formatted by Colorado Windows software. */ if (segments_per_track == 150 && tracks_per_tape == 28 && max_floppy_side == 6 && max_floppy_track == 150 && max_floppy_sector == 128) { TRACE(-1, "the famous Colorado bug: max_floppy_track off by one !"); max_floppy_track = 149; } segments_per_head = ((max_floppy_sector / SECTORS_PER_SEGMENT) * (max_floppy_track + 1)); /* * Verify drive_configuration with tape parameters */ if (segments_per_head == 0 || segments_per_cylinder == 0 || ((segments_per_track * tracks_per_tape - 1) / segments_per_head != max_floppy_side) || (segments_per_head / segments_per_cylinder - 1 != max_floppy_track) || (segments_per_cylinder * SECTORS_PER_SEGMENT != max_floppy_sector) #ifdef TESTING || (format_code == 4 && (max_floppy_track != 254 || max_floppy_sector != 128)) #endif ) { TRACE(1, "Tape parameters inconsistency, please report"); TRACE_EXIT; return -EIO; } first_data_segment = GET2(address, 10); /* first data segment */ TRACEi(4, "first data segment:", first_data_segment); extract_bad_sector_map(address); /* Find the highest segment id that allows still one full * deblock_buffer to be written to tape. */ ftape_last_segment.size = 0; for (i = segments_per_track * tracks_per_tape - 1; i >= 0; --i) { int space = SECTORS_PER_SEGMENT - 3 - count_ones(get_bad_sector_entry(i)); if (space > 0) { ftape_last_segment.size += space; /* sectors free */ ftape_last_segment.free = (ftape_last_segment.size - sizeof(deblock_buffer) / SECTOR_SIZE); if (ftape_last_segment.free >= 0) { ftape_last_segment.id = i; TRACEx2(4, "`last' segment is %d, %d Kb", ftape_last_segment.id, ftape_last_segment.size); break; } } } /* Copy the failed sector log into our local buffer. */ if (!ftape_validate_label(&deblock_buffer[30])) { TRACE(-1, "This tape has no `Linux raw format' label,\n" "***** Use `mt' to erase this tape if you want to use file marks !"); } else { extract_file_marks(address); } ftape_reset_position(); TRACE_EXIT; return 0; } int _ftape_read(char *buff, int req_len) { TRACE_FUN(5, "_ftape_read"); int result = 0; int cnt; int to_do = req_len; static int remaining; int bytes_read = 0; if (ftape_offline || !formatted || no_tape) { TRACEx3(-1, "offline = %d, formatted = %d, no_tape = %d", ftape_offline, formatted, no_tape); result = -EIO; } else { history.used |= 1; if (first_data_segment == -1) { result = read_header_segment(deblock_buffer); } } if (result < 0) { TRACE_EXIT; return result; } /* As GNU tar doesn't accept partial read counts when the multiple * volume flag is set, we make sure to return the requested amount * of data. Except, of course, at the end of the tape or file mark. */ while (to_do > 0) { /* don't return with a partial count ! */ /* If we're reading the `last' segment(s) on tape, make sure we don't * get more than 29 Kb from it (As it only contains this much). * This works only for sequential access, so random access should * stay away from this `last' segment. * Note: ftape_seg_pos points to the next segment that will be * read, so it's one too high here! */ if (!eof_mark && ftape_seg_pos - 1 >= ftape_last_segment.id) { TRACEi(5, "remaining of last segment:", remaining); if (to_do > remaining) { to_do = remaining; /* fake a smaller request */ TRACE(5, "clipped request to remaining"); } } while (!eof_mark && buf_len_rd == 0) { /* When starting to read the `last' segment, set remaining */ if (ftape_seg_pos == ftape_last_segment.id) { remaining = sizeof(deblock_buffer); TRACEi(5, "remaining set to:", remaining); } result = read_segment(ftape_seg_pos, deblock_buffer, &eof_mark, 1); if (result < 0) { if (result == -ENODATA) { /* Unable to recover tape data, return error and skip bad spot. */ ++ftape_seg_pos; } TRACEx1(4, "read_segment result: %d", result); TRACE_EXIT; return result; } /* Allow escape from this loop on signal ! */ if (current->signal & _DONT_BLOCK) { TRACE(2, "interrupted by non-blockable signal"); TRACE_EXIT; return -EINTR; } buf_pos_rd = 0; buf_len_rd = result; ++ftape_seg_pos; } /* Take as much as we can use */ cnt = (buf_len_rd < to_do) ? buf_len_rd : to_do; TRACEi(7, "nr bytes just read:", cnt); if (cnt > 0) { result = verify_area(VERIFY_WRITE, buff, cnt); if (result) { TRACEx1(1, "verify_area failed, exitcode = %d", result); TRACE_EXIT; return -EIO; } copy_to_user(buff, deblock_buffer + buf_pos_rd, cnt); buff += cnt; to_do -= cnt; /* what's left from req_len */ remaining -= cnt; /* what remains on this tape */ bytes_read += cnt; /* what we got so far */ buf_pos_rd += cnt; /* index in buffer */ buf_len_rd -= cnt; /* remaining bytes in buffer */ } if (eof_mark && buf_len_rd == 0) { /* nothing left */ TRACE(5, "partial count because of eof mark"); if (bytes_read == 0) { eof_mark = 0; /* no need for mark next read */ } break; } } TRACE_EXIT; return bytes_read; }