patch-1.3.72 linux/drivers/char/ftape/ftape-eof.c
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- Lines: 556
- Date:
Wed Mar 6 15:07:19 1996
- Orig file:
v1.3.71/linux/drivers/char/ftape/ftape-eof.c
- Orig date:
Thu Jan 1 02:00:00 1970
diff -u --recursive --new-file v1.3.71/linux/drivers/char/ftape/ftape-eof.c linux/drivers/char/ftape/ftape-eof.c
@@ -0,0 +1,555 @@
+
+/*
+ * 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/module.h>
+#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;
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov
with Sam's (original) version of this