/*
* 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;
}
