patch-2.1.66 linux/drivers/char/ftape/ftape-eof.c

• Lines: 555
• Date: Wed Dec 31 16:00:00 1969
• Orig file: v2.1.65/linux/drivers/char/ftape/ftape-eof.c
• Orig date: Thu Mar 14 01:53:44 1996

diff -u --recursive --new-file v2.1.65/linux/drivers/char/ftape/ftape-eof.c linux/drivers/char/ftape/ftape-eof.c
@@ -1,554 +0,0 @@
-
-/*
- *      Copyright (C) 1994-1995 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-eof.c,v $
- $Author: bas $
- *
- $Revision: 1.21 $
- $Date: 1995/05/27 08:54:21 $
- $State: Beta $
- *
- *      This file contains the eof mark handling code
- *      for the QIC-40/80 floppy-tape driver for Linux.
- */
-
-#include <linux/ftape.h>
-#include <linux/string.h>
-#include <linux/errno.h>
-
-#include "tracing.h"
-#include "ftape-eof.h"
-#include "ftape-write.h"
-#include "ftape-read.h"
-#include "ftape-rw.h"
-#include "ftape-ctl.h"
-#include "ftape-bsm.h"
-
-/*      Global vars.
- */
-int failed_sector_log_changed = 0;
-int eof_mark = 0;
-
-/*      Local vars.
- */
-static struct failed_sector_entry {
-	unsigned short segment;
-	unsigned short sector;
-} *eof_mark_ptr;
-
-typedef union {
-	struct failed_sector_entry mark;
-	unsigned long entry;
-} eof_mark_union;
-
-/*  a copy of the failed sector log from the header segment.
- */
-static eof_mark_union eof_map[(2048 - 256) / 4];
-
-/*  index into eof_map table pointing to last found eof mark.
- */
-static int eof_index;
-
-/*  number of eof marks (entries in bad sector log) on tape.
- */
-static int nr_of_eof_marks = -1;
-
-static char linux_tape_label[] = "Linux raw format V";
-enum {
-	min_fmt_version = 1, max_fmt_version = 2
-};
-static unsigned ftape_fmt_version = 0;
-
-
-/*  Ftape (mis)uses the bad sector log to record end-of-file marks.
- *  Initially (when the tape is erased) all entries in the bad sector
- *  log are added to the tape's bad sector map. The bad sector log
- *  then is cleared.
- *
- *  The bad sector log normally contains entries of the form:
- *  even 16-bit word: segment number of bad sector
- *   odd 16-bit word: encoded date
- *  There can be a total of 448 entries (1792 bytes).
- *
- *  My guess is that no program is using this bad sector log (the
- *  format seems useless as there is no indication of the bad sector
- *  itself, only the segment)
- *  However, if any program does use the bad sector log, the format
- *  used by ftape will let the program think there are some bad sectors
- *  and no harm is done.
- *  
- *  The eof mark entries that ftape stores in the bad sector log:
- *  even 16-bit word: segment number of eof mark
- *   odd 16-bit word: sector number of eof mark [1..32]
- *  
- *  The eof_map as maintained is a sorted list of eof mark entries.
- *
- *
- *  The tape name field in the header segments is used to store a
- *  linux tape identification string and a version number.
- *  This way the tape can be recognized as a Linux raw format
- *  tape when using tools under other OS's.
- *
- *  'Wide' QIC tapes (format code 4) don't have a failed sector list
- *  anymore. That space is used for the (longer) bad sector map that
- *  now is a variable length list too.
- *  We now store our end-of-file marker list after the bad-sector-map
- *  on tape. The list is delimited by a (long) 0 entry.
- */
-
-int ftape_validate_label(char *label)
-{
-	TRACE_FUN(8, "ftape_validate_label");
-	int result = 0;
-
-	TRACEx1(4, "tape  label = `%s'", label);
-	ftape_fmt_version = 0;
-	if (memcmp(label, linux_tape_label, strlen(linux_tape_label)) == 0) {
-		int pos = strlen(linux_tape_label);
-		while (label[pos] >= '0' && label[pos] <= '9') {
-			ftape_fmt_version *= 10;
-			ftape_fmt_version = label[pos++] - '0';
-		}
-		result = (ftape_fmt_version >= min_fmt_version &&
-			  ftape_fmt_version <= max_fmt_version);
-	}
-	TRACEx1(4, "format version = %d", ftape_fmt_version);
-	TRACE_EXIT;
-	return result;
-}
-
-static byte *
- find_end_of_eof_list(byte * ptr, byte * limit)
-{
-	while (ptr + 3 < limit) {
-		if (*(unsigned long *) ptr) {
-			++(unsigned long *) ptr;
-		} else {
-			return ptr;
-		}
-	}
-	return NULL;
-}
-
-void reset_eof_list(void)
-{
-	TRACE_FUN(8, "reset_eof_list");
-
-	eof_mark_ptr = &eof_map[0].mark;
-	eof_index = 0;
-	eof_mark = 0;
-	TRACE_EXIT;
-}
-
-/*  Test if `segment' has an eof mark set (optimized for sequential access).
- *  return 0 if not eof mark or sector number (> 0) if eof mark set.
- */
-int check_for_eof(unsigned segment)
-{
-	TRACE_FUN(8, "check_for_eof");
-	static unsigned last_reference = INT_MAX;
-	int result;
-
-	if (segment < last_reference) {
-		reset_eof_list();
-	}
-	last_reference = segment;
-	while (eof_index < nr_of_eof_marks && segment > eof_mark_ptr->segment) {
-		++eof_mark_ptr;
-		++eof_index;
-	}
-	if (eof_index < nr_of_eof_marks && segment == eof_mark_ptr->segment) {
-		TRACEx3(5, "hit mark %d/%d at index %d",
-			eof_map[eof_index].mark.segment, eof_map[eof_index].mark.sector,
-			eof_index);
-		if (eof_mark_ptr->sector >= SECTORS_PER_SEGMENT) {
-			TRACEx2(-1, "Bad file mark detected: %d/%d",
-			    eof_mark_ptr->segment, eof_mark_ptr->sector);
-			result = 0;	/* return bogus (but valid) value */
-		} else {
-			result = eof_mark_ptr->sector;
-		}
-	} else {
-		result = 0;
-	}
-	TRACE_EXIT;
-	return result;
-}
-
-void clear_eof_mark_if_set(unsigned segment, unsigned byte_count)
-{
-	TRACE_FUN(5, "clear_eof_mark_if_set");
-	if (ftape_fmt_version != 0 &&
-	    check_for_eof(segment) > 0 &&
-	    byte_count >= eof_mark_ptr->sector * SECTOR_SIZE) {
-		TRACEx3(5, "clearing mark %d/%d at index %d",
-		 eof_mark_ptr->segment, eof_mark_ptr->sector, eof_index);
-		memmove(&eof_map[eof_index], &eof_map[eof_index + 1],
-			(nr_of_eof_marks - eof_index) * sizeof(*eof_map));
-		--nr_of_eof_marks;
-		failed_sector_log_changed = 1;
-	}
-	TRACE_EXIT;
-}
-
-void put_file_mark_in_map(unsigned segment, unsigned sector)
-{
-	TRACE_FUN(8, "put_file_mark_in_map");
-	eof_mark_union new;
-	int index;
-	eof_mark_union *ptr;
-
-	if (ftape_fmt_version != 0) {
-		new.mark.segment = segment;
-		new.mark.sector = sector;
-		for (index = 0, ptr = &eof_map[0];
-		  index < nr_of_eof_marks && ptr->mark.segment < segment;
-		     ++index, ++ptr) {
-		}
-		if (index < nr_of_eof_marks) {
-			if (ptr->mark.segment == segment) {
-				/* overwrite */
-				if (ptr->mark.sector == sector) {
-					TRACEx2(5, "mark %d/%d already exists",
-						new.mark.segment, new.mark.sector);
-				} else {
-					TRACEx5(5, "overwriting %d/%d at index %d with %d/%d",
-						ptr->mark.segment, ptr->mark.sector, index,
-						new.mark.segment, new.mark.sector);
-					ptr->entry = new.entry;
-					failed_sector_log_changed = 1;
-				}
-			} else {
-				/* insert */
-				TRACEx5(5, "inserting %d/%d at index %d before %d/%d",
-				new.mark.segment, new.mark.sector, index,
-				    ptr->mark.segment, ptr->mark.sector);
-				memmove(ptr + 1, ptr, (nr_of_eof_marks - index) * sizeof(*eof_map));
-				ptr->entry = new.entry;
-				++nr_of_eof_marks;
-				failed_sector_log_changed = 1;
-			}
-		} else {
-			/* append */
-			TRACEx3(5, "appending %d/%d at index %d",
-				new.mark.segment, new.mark.sector, index);
-			ptr->entry = new.entry;
-			++nr_of_eof_marks;
-			failed_sector_log_changed = 1;
-		}
-	}
-	TRACE_EXIT;
-}
-
-/*  Write count file marks to tape starting at first non-bad
- *  sector following the given segment and sector.
- *  sector = base 1 !
- */
-int ftape_weof(unsigned count, unsigned segment, unsigned sector)
-{
-	TRACE_FUN(5, "ftape_weof");
-	int result = 0;
-	unsigned long mask = get_bad_sector_entry(segment);
-	unsigned sector_nr = 0;
-
-	if (ftape_fmt_version != 0) {
-		if (sector < 1 || sector > 29 ||
-		    segment + count >= ftape_last_segment.id) {
-			TRACEx3(5, "parameter out of range: %d, %d, %d", count, segment, sector);
-			result = -EIO;
-		} else {
-			while (count-- > 0) {
-				do {	/* count logical sectors */
-					do {	/* skip until good sector */
-						while (mask & 1) {	/* skip bad sectors */
-							++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;
-}