git.oblomov.eu Git - linux-2.6/blob - drivers/char/ftape/zftape/zftape-vtbl.c

   1 /*
   2  *      Copyright (c) 1995-1997 Claus-Justus Heine
   3
   4  This program is free software; you can redistribute it and/or
   5  modify it under the terms of the GNU General Public License as
   6  published by the Free Software Foundation; either version 2, or (at
   7  your option) any later version.
   8
   9  This program is distributed in the hope that it will be useful, but
  10  WITHOUT ANY WARRANTY; without even the implied warranty of
  11  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  General Public License for more details.
  13
  14  You should have received a copy of the GNU General Public License
  15  along with this program; see the file COPYING.  If not, write to
  16  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  17  USA.
  18
  19  *
  20  * $Source: /homes/cvs/ftape-stacked/ftape/zftape/zftape-vtbl.c,v $
  21  * $Revision: 1.7.6.1 $
  22  * $Date: 1997/11/24 13:48:31 $
  23  *
  24  *      This file defines a volume table as defined in various QIC
  25  *      standards.
  26  *
  27  *      This is a minimal implementation, just allowing ordinary DOS
  28  *      :( prgrams to identify the cartridge as used.
  29  */
  30
  31 #include <linux/errno.h>
  32 #include <linux/mm.h>
  33 #include <linux/slab.h>
  34
  35 #include <linux/zftape.h>
  36 #include "../zftape/zftape-init.h"
  37 #include "../zftape/zftape-eof.h"
  38 #include "../zftape/zftape-ctl.h"
  39 #include "../zftape/zftape-write.h"
  40 #include "../zftape/zftape-read.h"
  41 #include "../zftape/zftape-rw.h"
  42 #include "../zftape/zftape-vtbl.h"
  43
  44 #define ZFT_CMAP_HACK /* leave this defined to hide the compression map */
  45
  46 /*
  47  *  global variables
  48  */
  49 int zft_qic_mode   = 1; /* use the vtbl */
  50 int zft_old_ftape; /* prevents old ftaped tapes to be overwritten */
  51 int zft_volume_table_changed; /* for write_header_segments() */
  52
  53 /*
  54  *  private variables (only exported for inline functions)
  55  */
  56 LIST_HEAD(zft_vtbl);
  57
  58 /*  We could also allocate these dynamically when extracting the volume table
  59  *  sizeof(zft_volinfo) is about 32 or something close to that
  60  */
  61 static zft_volinfo  tape_vtbl;
  62 static zft_volinfo  eot_vtbl;
  63 static zft_volinfo *cur_vtbl;
  64
  65 static inline void zft_new_vtbl_entry(void)
  66 {
  67         struct list_head *tmp = &zft_last_vtbl->node;
  68         zft_volinfo *new = zft_kmalloc(sizeof(zft_volinfo));
  69
  70         list_add(&new->node, tmp);
  71         new->count = zft_eom_vtbl->count ++;
  72 }
  73
  74 void zft_free_vtbl(void)
  75 {
  76         for (;;) {
  77                 struct list_head *tmp = zft_vtbl.prev;
  78                 zft_volinfo *vtbl;
  79
  80                 if (tmp == &zft_vtbl)
  81                         break;
  82                 list_del(tmp);
  83                 vtbl = list_entry(tmp, zft_volinfo, node);
  84                 zft_kfree(vtbl, sizeof(zft_volinfo));
  85         }
  86         INIT_LIST_HEAD(&zft_vtbl);
  87         cur_vtbl = NULL;
  88 }
  89
  90 /*  initialize vtbl, called by ftape_new_cartridge()
  91  */
  92 void zft_init_vtbl(void)
  93 {
  94         zft_volinfo *new;
  95
  96         zft_free_vtbl();
  97
  98         /*  Create the two dummy vtbl entries
  99          */
 100         new = zft_kmalloc(sizeof(zft_volinfo));
 101         list_add(&new->node, &zft_vtbl);
 102         new = zft_kmalloc(sizeof(zft_volinfo));
 103         list_add(&new->node, &zft_vtbl);
 104         zft_head_vtbl->end_seg   = ft_first_data_segment;
 105         zft_head_vtbl->blk_sz    = zft_blk_sz;
 106         zft_head_vtbl->count     = -1;
 107         zft_eom_vtbl->start_seg  = ft_first_data_segment + 1;
 108         zft_eom_vtbl->end_seg    = ft_last_data_segment + 1;
 109         zft_eom_vtbl->blk_sz     = zft_blk_sz;
 110         zft_eom_vtbl->count      = 0;
 111
 112         /*  Reset the pointer for zft_find_volume()
 113          */
 114         cur_vtbl = zft_eom_vtbl;
 115
 116         /* initialize the dummy vtbl entries for zft_qic_mode == 0
 117          */
 118         eot_vtbl.start_seg       = ft_last_data_segment + 1;
 119         eot_vtbl.end_seg         = ft_last_data_segment + 1;
 120         eot_vtbl.blk_sz          = zft_blk_sz;
 121         eot_vtbl.count           = -1;
 122         tape_vtbl.start_seg = ft_first_data_segment;
 123         tape_vtbl.end_seg   = ft_last_data_segment;
 124         tape_vtbl.blk_sz    = zft_blk_sz;
 125         tape_vtbl.size      = zft_capacity;
 126         tape_vtbl.count     = 0;
 127 }
 128
 129 /* check for a valid VTBL signature.
 130  */
 131 static int vtbl_signature_valid(__u8 signature[4])
 132 {
 133         const char *vtbl_ids[] = VTBL_IDS; /* valid signatures */
 134         int j;
 135
 136         for (j = 0;
 137              (j < NR_ITEMS(vtbl_ids)) && (memcmp(signature, vtbl_ids[j], 4) != 0);
 138              j++);
 139         return j < NR_ITEMS(vtbl_ids);
 140 }
 141
 142 /* We used to store the block-size of the volume in the volume-label,
 143  * using the keyword "blocksize". The blocksize written to the
 144  * volume-label is in bytes.
 145  *
 146  * We use this now only for compatibility with old zftape version. We
 147  * store the blocksize directly as binary number in the vendor
 148  * extension part of the volume entry.
 149  */
 150 static int check_volume_label(const char *label, int *blk_sz)
 151 {
 152         int valid_format;
 153         char *blocksize;
 154         TRACE_FUN(ft_t_flow);
 155
 156         TRACE(ft_t_noise, "called with \"%s\" / \"%s\"", label, ZFT_VOL_NAME);
 157         if (strncmp(label, ZFT_VOL_NAME, strlen(ZFT_VOL_NAME)) != 0) {
 158                 *blk_sz = 1; /* smallest block size that we allow */
 159                 valid_format = 0;
 160         } else {
 161                 TRACE(ft_t_noise, "got old style zftape vtbl entry");
 162                 /* get the default blocksize */
 163                 /* use the kernel strstr()   */
 164                 blocksize= strstr(label, " blocksize ");
 165                 if (blocksize) {
 166                         blocksize += strlen(" blocksize ");
 167                         for(*blk_sz= 0;
 168                             *blocksize >= '0' && *blocksize <= '9';
 169                             blocksize++) {
 170                                 *blk_sz *= 10;
 171                                 *blk_sz += *blocksize - '0';
 172                         }
 173                         if (*blk_sz > ZFT_MAX_BLK_SZ) {
 174                                 *blk_sz= 1;
 175                                 valid_format= 0;
 176                         } else {
 177                                 valid_format = 1;
 178                         }
 179                 } else {
 180                         *blk_sz= 1;
 181                         valid_format= 0;
 182                 }
 183         }
 184         TRACE_EXIT valid_format;
 185 }
 186
 187 /*   check for a zftape volume
 188  */
 189 static int check_volume(__u8 *entry, zft_volinfo *volume)
 190 {
 191         TRACE_FUN(ft_t_flow);
 192
 193         if(strncmp(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
 194                    strlen(ZFTAPE_SIG)) == 0) {
 195                 TRACE(ft_t_noise, "got new style zftape vtbl entry");
 196                 volume->blk_sz = GET2(entry, VTBL_EXT+EXT_ZFTAPE_BLKSZ);
 197                 volume->qic113 = entry[VTBL_EXT+EXT_ZFTAPE_QIC113];
 198                 TRACE_EXIT 1;
 199         } else {
 200                 TRACE_EXIT check_volume_label(&entry[VTBL_DESC], &volume->blk_sz);
 201         }
 202 }
 203
 204
 205 /* create zftape specific vtbl entry, the volume bounds are inserted
 206  * in the calling function, zft_create_volume_headers()
 207  */
 208 static void create_zft_volume(__u8 *entry, zft_volinfo *vtbl)
 209 {
 210         TRACE_FUN(ft_t_flow);
 211
 212         memset(entry, 0, VTBL_SIZE);
 213         memcpy(&entry[VTBL_SIG], VTBL_ID, 4);
 214         sprintf(&entry[VTBL_DESC], ZFT_VOL_NAME" %03d", vtbl->count);
 215         entry[VTBL_FLAGS] = (VTBL_FL_NOT_VERIFIED | VTBL_FL_SEG_SPANNING);
 216         entry[VTBL_M_NO] = 1; /* multi_cartridge_count */
 217         strcpy(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG);
 218         PUT2(entry, VTBL_EXT+EXT_ZFTAPE_BLKSZ, vtbl->blk_sz);
 219         if (zft_qic113) {
 220                 PUT8(entry, VTBL_DATA_SIZE, vtbl->size);
 221                 entry[VTBL_CMPR] = VTBL_CMPR_UNREG;
 222                 if (vtbl->use_compression) { /* use compression: */
 223                         entry[VTBL_CMPR] |= VTBL_CMPR_USED;
 224                 }
 225                 entry[VTBL_EXT+EXT_ZFTAPE_QIC113] = 1;
 226         } else {
 227                 PUT4(entry, VTBL_DATA_SIZE, vtbl->size);
 228                 entry[VTBL_K_CMPR] = VTBL_CMPR_UNREG;
 229                 if (vtbl->use_compression) { /* use compression: */
 230                         entry[VTBL_K_CMPR] |= VTBL_CMPR_USED;
 231                 }
 232         }
 233         if (ft_format_code == fmt_big) {
 234                 /* SCSI like vtbl, store the number of used
 235                  * segments as 4 byte value
 236                  */
 237                 PUT4(entry, VTBL_SCSI_SEGS, vtbl->end_seg-vtbl->start_seg + 1);
 238         } else {
 239                 /* normal, QIC-80MC like vtbl
 240                  */
 241                 PUT2(entry, VTBL_START, vtbl->start_seg);
 242                 PUT2(entry, VTBL_END, vtbl->end_seg);
 243         }
 244         TRACE_EXIT;
 245 }
 246
 247 /* this one creates the volume headers for each volume. It is assumed
 248  * that buffer already contains the old volume-table, so that vtbl
 249  * entries without the zft_volume flag set can savely be ignored.
 250  */
 251 static void zft_create_volume_headers(__u8 *buffer)
 252 {
 253         __u8 *entry;
 254         struct list_head *tmp;
 255         zft_volinfo *vtbl;
 256         TRACE_FUN(ft_t_flow);
 257
 258 #ifdef ZFT_CMAP_HACK
 259         if((strncmp(&buffer[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
 260                     strlen(ZFTAPE_SIG)) == 0) &&
 261            buffer[VTBL_EXT+EXT_ZFTAPE_CMAP] != 0) {
 262                 TRACE(ft_t_noise, "deleting cmap volume");
 263                 memmove(buffer, buffer + VTBL_SIZE,
 264                         FT_SEGMENT_SIZE - VTBL_SIZE);
 265         }
 266 #endif
 267         entry = buffer;
 268         for (tmp = zft_head_vtbl->node.next;
 269              tmp != &zft_eom_vtbl->node;
 270              tmp = tmp->next) {
 271                 vtbl = list_entry(tmp, zft_volinfo, node);
 272                 /* we now fill in the values only for newly created volumes.
 273                  */
 274                 if (vtbl->new_volume) {
 275                         create_zft_volume(entry, vtbl);
 276                         vtbl->new_volume = 0; /* clear the flag */
 277                 }
 278
 279                 DUMP_VOLINFO(ft_t_noise, &entry[VTBL_DESC], vtbl);
 280                 entry += VTBL_SIZE;
 281         }
 282         memset(entry, 0, FT_SEGMENT_SIZE - zft_eom_vtbl->count * VTBL_SIZE);
 283         TRACE_EXIT;
 284 }
 285
 286 /*  write volume table to tape. Calls zft_create_volume_headers()
 287  */
 288 int zft_update_volume_table(unsigned int segment)
 289 {
 290         int result = 0;
 291         __u8 *verify_buf = NULL;
 292         TRACE_FUN(ft_t_flow);
 293
 294         TRACE_CATCH(result = ftape_read_segment(ft_first_data_segment,
 295                                                 zft_deblock_buf,
 296                                                 FT_RD_SINGLE),);
 297         zft_create_volume_headers(zft_deblock_buf);
 298         TRACE(ft_t_noise, "writing volume table segment %d", segment);
 299         if (zft_vmalloc_once(&verify_buf, FT_SEGMENT_SIZE) == 0) {
 300                 TRACE_CATCH(zft_verify_write_segments(segment,
 301                                                       zft_deblock_buf, result,
 302                                                       verify_buf),
 303                             zft_vfree(&verify_buf, FT_SEGMENT_SIZE));
 304                 zft_vfree(&verify_buf, FT_SEGMENT_SIZE);
 305         } else {
 306                 TRACE_CATCH(ftape_write_segment(segment, zft_deblock_buf,
 307                                                 FT_WR_SINGLE),);
 308         }
 309         TRACE_EXIT 0;
 310 }
 311
 312 /* non zftape volumes are handled in raw mode. Thus we need to
 313  * calculate the raw amount of data contained in those segments.
 314  */
 315 static void extract_alien_volume(__u8 *entry, zft_volinfo *vtbl)
 316 {
 317         TRACE_FUN(ft_t_flow);
 318
 319         vtbl->size  = (zft_calc_tape_pos(zft_last_vtbl->end_seg+1) -
 320                        zft_calc_tape_pos(zft_last_vtbl->start_seg));
 321         vtbl->use_compression = 0;
 322         vtbl->qic113 = zft_qic113;
 323         if (vtbl->qic113) {
 324                 TRACE(ft_t_noise,
 325                       "Fake alien volume's size from " LL_X " to " LL_X,
 326                       LL(GET8(entry, VTBL_DATA_SIZE)), LL(vtbl->size));
 327         } else {
 328                 TRACE(ft_t_noise,
 329                       "Fake alien volume's size from %d to " LL_X,
 330                       (int)GET4(entry, VTBL_DATA_SIZE), LL(vtbl->size));
 331         }
 332         TRACE_EXIT;
 333 }
 334
 335
 336 /* extract an zftape specific volume
 337  */
 338 static void extract_zft_volume(__u8 *entry, zft_volinfo *vtbl)
 339 {
 340         TRACE_FUN(ft_t_flow);
 341
 342         if (vtbl->qic113) {
 343                 vtbl->size = GET8(entry, VTBL_DATA_SIZE);
 344                 vtbl->use_compression =
 345                         (entry[VTBL_CMPR] & VTBL_CMPR_USED) != 0;
 346         } else {
 347                 vtbl->size = GET4(entry, VTBL_DATA_SIZE);
 348                 if (entry[VTBL_K_CMPR] & VTBL_CMPR_UNREG) {
 349                         vtbl->use_compression =
 350                                 (entry[VTBL_K_CMPR] & VTBL_CMPR_USED) != 0;
 351                 } else if (entry[VTBL_CMPR] & VTBL_CMPR_UNREG) {
 352                         vtbl->use_compression =
 353                                 (entry[VTBL_CMPR] & VTBL_CMPR_USED) != 0;
 354                 } else {
 355                         TRACE(ft_t_warn, "Geeh! There is something wrong:\n"
 356                               KERN_INFO "QIC compression (Rev = K): %x\n"
 357                               KERN_INFO "QIC compression (Rev > K): %x",
 358                               entry[VTBL_K_CMPR], entry[VTBL_CMPR]);
 359                 }
 360         }
 361         TRACE_EXIT;
 362 }
 363
 364 /* extract the volume table from buffer. "buffer" must already contain
 365  * the vtbl-segment
 366  */
 367 int zft_extract_volume_headers(__u8 *buffer)
 368 {
 369         __u8 *entry;
 370         TRACE_FUN(ft_t_flow);
 371
 372         zft_init_vtbl();
 373         entry = buffer;
 374 #ifdef ZFT_CMAP_HACK
 375         if ((strncmp(&entry[VTBL_EXT+EXT_ZFTAPE_SIG], ZFTAPE_SIG,
 376                      strlen(ZFTAPE_SIG)) == 0) &&
 377             entry[VTBL_EXT+EXT_ZFTAPE_CMAP] != 0) {
 378                 TRACE(ft_t_noise, "ignoring cmap volume");
 379                 entry += VTBL_SIZE;
 380         }
 381 #endif
 382         /* the end of the vtbl is indicated by an invalid signature
 383          */
 384         while (vtbl_signature_valid(&entry[VTBL_SIG]) &&
 385                (entry - buffer) < FT_SEGMENT_SIZE) {
 386                 zft_new_vtbl_entry();
 387                 if (ft_format_code == fmt_big) {
 388                         /* SCSI like vtbl, stores only the number of
 389                          * segments used
 390                          */
 391                         unsigned int num_segments= GET4(entry, VTBL_SCSI_SEGS);
 392                         zft_last_vtbl->start_seg = zft_eom_vtbl->start_seg;
 393                         zft_last_vtbl->end_seg =
 394                                 zft_last_vtbl->start_seg + num_segments - 1;
 395                 } else {
 396                         /* `normal', QIC-80 like vtbl
 397                          */
 398                         zft_last_vtbl->start_seg = GET2(entry, VTBL_START);
 399                         zft_last_vtbl->end_seg   = GET2(entry, VTBL_END);
 400                 }
 401                 zft_eom_vtbl->start_seg  = zft_last_vtbl->end_seg + 1;
 402                 /* check if we created this volume and get the
 403                  * blk_sz
 404                  */
 405                 zft_last_vtbl->zft_volume = check_volume(entry, zft_last_vtbl);
 406                 if (zft_last_vtbl->zft_volume == 0) {
 407                         extract_alien_volume(entry, zft_last_vtbl);
 408                 } else {
 409                         extract_zft_volume(entry, zft_last_vtbl);
 410                 }
 411                 DUMP_VOLINFO(ft_t_noise, &entry[VTBL_DESC], zft_last_vtbl);
 412                 entry +=VTBL_SIZE;
 413         }
 414 #if 0
 415 /*
 416  *  undefine to test end of tape handling
 417  */
 418         zft_new_vtbl_entry();
 419         zft_last_vtbl->start_seg = zft_eom_vtbl->start_seg;
 420         zft_last_vtbl->end_seg   = ft_last_data_segment - 10;
 421         zft_last_vtbl->blk_sz          = zft_blk_sz;
 422         zft_last_vtbl->zft_volume      = 1;
 423         zft_last_vtbl->qic113          = zft_qic113;
 424         zft_last_vtbl->size = (zft_calc_tape_pos(zft_last_vtbl->end_seg+1)
 425                                - zft_calc_tape_pos(zft_last_vtbl->start_seg));
 426 #endif
 427         TRACE_EXIT 0;
 428 }
 429
 430 /* this functions translates the failed_sector_log, misused as
 431  * EOF-marker list, into a virtual volume table. The table mustn't be
 432  * written to tape, because this would occupy the first data segment,
 433  * which should be the volume table, but is actually the first segment
 434  * that is filled with data (when using standard ftape).  We assume,
 435  * that we get a non-empty failed_sector_log.
 436  */
 437 int zft_fake_volume_headers (eof_mark_union *eof_map, int num_failed_sectors)
 438 {
 439         unsigned int segment, sector;
 440         int have_eom = 0;
 441         int vol_no;
 442         TRACE_FUN(ft_t_flow);
 443
 444         if ((num_failed_sectors >= 2) &&
 445             (GET2(&eof_map[num_failed_sectors - 1].mark.segment, 0)
 446              ==
 447              GET2(&eof_map[num_failed_sectors - 2].mark.segment, 0) + 1) &&
 448             (GET2(&eof_map[num_failed_sectors - 1].mark.date, 0) == 1)) {
 449                 /* this should be eom. We keep the remainder of the
 450                  * tape as another volume.
 451                  */
 452                 have_eom = 1;
 453         }
 454         zft_init_vtbl();
 455         zft_eom_vtbl->start_seg = ft_first_data_segment;
 456         for(vol_no = 0; vol_no < num_failed_sectors - have_eom; vol_no ++) {
 457                 zft_new_vtbl_entry();
 458
 459                 segment = GET2(&eof_map[vol_no].mark.segment, 0);
 460                 sector  = GET2(&eof_map[vol_no].mark.date, 0);
 461
 462                 zft_last_vtbl->start_seg  = zft_eom_vtbl->start_seg;
 463                 zft_last_vtbl->end_seg    = segment;
 464                 zft_eom_vtbl->start_seg  = segment + 1;
 465                 zft_last_vtbl->blk_sz     = 1;
 466                 zft_last_vtbl->size       =
 467                         (zft_calc_tape_pos(zft_last_vtbl->end_seg)
 468                          - zft_calc_tape_pos(zft_last_vtbl->start_seg)
 469                          + (sector-1) * FT_SECTOR_SIZE);
 470                 TRACE(ft_t_noise,
 471                       "failed sector log: segment: %d, sector: %d",
 472                       segment, sector);
 473                 DUMP_VOLINFO(ft_t_noise, "Faked volume", zft_last_vtbl);
 474         }
 475         if (!have_eom) {
 476                 zft_new_vtbl_entry();
 477                 zft_last_vtbl->start_seg = zft_eom_vtbl->start_seg;
 478                 zft_last_vtbl->end_seg   = ft_last_data_segment;
 479                 zft_eom_vtbl->start_seg  = ft_last_data_segment + 1;
 480                 zft_last_vtbl->size      = zft_capacity;
 481                 zft_last_vtbl->size     -= zft_calc_tape_pos(zft_last_vtbl->start_seg);
 482                 zft_last_vtbl->blk_sz    = 1;
 483                 DUMP_VOLINFO(ft_t_noise, "Faked volume",zft_last_vtbl);
 484         }
 485         TRACE_EXIT 0;
 486 }
 487
 488 /* update the internal volume table
 489  *
 490  * if before start of last volume: erase all following volumes if
 491  * inside a volume: set end of volume to infinity
 492  *
 493  * this function is intended to be called every time _ftape_write() is
 494  * called
 495  *
 496  * return: 0 if no new volume was created, 1 if a new volume was
 497  * created
 498  *
 499  * NOTE: we don't need to check for zft_mode as ftape_write() does
 500  * that already. This function gets never called without accessing
 501  * zftape via the *qft* devices
 502  */
 503
 504 int zft_open_volume(zft_position *pos, int blk_sz, int use_compression)
 505 {
 506         TRACE_FUN(ft_t_flow);
 507
 508         if (!zft_qic_mode) {
 509                 TRACE_EXIT 0;
 510         }
 511         if (zft_tape_at_lbot(pos)) {
 512                 zft_init_vtbl();
 513                 if(zft_old_ftape) {
 514                         /* clear old ftape's eof marks */
 515                         zft_clear_ftape_file_marks();
 516                         zft_old_ftape = 0; /* no longer old ftape */
 517                 }
 518                 zft_reset_position(pos);
 519         }
 520         if (pos->seg_pos != zft_last_vtbl->end_seg + 1) {
 521                 TRACE_ABORT(-EIO, ft_t_bug,
 522                       "BUG: seg_pos: %d, zft_last_vtbl->end_seg: %d",
 523                       pos->seg_pos, zft_last_vtbl->end_seg);
 524         }
 525         TRACE(ft_t_noise, "create new volume");
 526         if (zft_eom_vtbl->count >= ZFT_MAX_VOLUMES) {
 527                 TRACE_ABORT(-ENOSPC, ft_t_err,
 528                             "Error: maxmimal number of volumes exhausted "
 529                             "(maxmimum is %d)", ZFT_MAX_VOLUMES);
 530         }
 531         zft_new_vtbl_entry();
 532         pos->volume_pos = pos->seg_byte_pos = 0;
 533         zft_last_vtbl->start_seg       = pos->seg_pos;
 534         zft_last_vtbl->end_seg         = ft_last_data_segment; /* infinity */
 535         zft_last_vtbl->blk_sz          = blk_sz;
 536         zft_last_vtbl->size            = zft_capacity;
 537         zft_last_vtbl->zft_volume      = 1;
 538         zft_last_vtbl->use_compression = use_compression;
 539         zft_last_vtbl->qic113          = zft_qic113;
 540         zft_last_vtbl->new_volume      = 1;
 541         zft_last_vtbl->open            = 1;
 542         zft_volume_table_changed = 1;
 543         zft_eom_vtbl->start_seg  = ft_last_data_segment + 1;
 544         TRACE_EXIT 0;
 545 }
 546
 547 /*  perform mtfsf, mtbsf, not allowed without zft_qic_mode
 548  */
 549 int zft_skip_volumes(int count, zft_position *pos)
 550 {
 551         const zft_volinfo *vtbl;
 552         TRACE_FUN(ft_t_flow);
 553
 554         TRACE(ft_t_noise, "count: %d", count);
 555
 556         vtbl= zft_find_volume(pos->seg_pos);
 557         while (count > 0 && vtbl != zft_eom_vtbl) {
 558                 vtbl = list_entry(vtbl->node.next, zft_volinfo, node);
 559                 count --;
 560         }
 561         while (count < 0 && vtbl != zft_first_vtbl) {
 562                 vtbl = list_entry(vtbl->node.prev, zft_volinfo, node);
 563                 count ++;
 564         }
 565         pos->seg_pos        = vtbl->start_seg;
 566         pos->seg_byte_pos   = 0;
 567         pos->volume_pos     = 0;
 568         pos->tape_pos       = zft_calc_tape_pos(pos->seg_pos);
 569         zft_just_before_eof = vtbl->size == 0;
 570         if (zft_cmpr_ops) {
 571                 (*zft_cmpr_ops->reset)();
 572         }
 573         zft_deblock_segment = -1; /* no need to keep cache */
 574         TRACE(ft_t_noise, "repositioning to:\n"
 575               KERN_INFO "zft_seg_pos        : %d\n"
 576               KERN_INFO "zft_seg_byte_pos   : %d\n"
 577               KERN_INFO "zft_tape_pos       : " LL_X "\n"
 578               KERN_INFO "zft_volume_pos     : " LL_X "\n"
 579               KERN_INFO "file number        : %d",
 580               pos->seg_pos, pos->seg_byte_pos,
 581               LL(pos->tape_pos), LL(pos->volume_pos), vtbl->count);
 582         zft_resid = count < 0 ? -count : count;
 583         TRACE_EXIT zft_resid ? -EINVAL : 0;
 584 }
 585
 586 /* the following simply returns the raw data position of the EOM
 587  * marker, MTIOCSIZE ioctl
 588  */
 589 __s64 zft_get_eom_pos(void)
 590 {
 591         if (zft_qic_mode) {
 592                 return zft_calc_tape_pos(zft_eom_vtbl->start_seg);
 593         } else {
 594                 /* there is only one volume in raw mode */
 595                 return zft_capacity;
 596         }
 597 }
 598
 599 /* skip to eom, used for MTEOM
 600  */
 601 void zft_skip_to_eom(zft_position *pos)
 602 {
 603         TRACE_FUN(ft_t_flow);
 604         pos->seg_pos      = zft_eom_vtbl->start_seg;
 605         pos->seg_byte_pos =
 606                 pos->volume_pos     =
 607                 zft_just_before_eof = 0;
 608         pos->tape_pos = zft_calc_tape_pos(pos->seg_pos);
 609         TRACE(ft_t_noise, "ftape positioned to segment %d, data pos " LL_X,
 610               pos->seg_pos, LL(pos->tape_pos));
 611         TRACE_EXIT;
 612 }
 613
 614 /*  write an EOF-marker by setting zft_last_vtbl->end_seg to seg_pos.
 615  *  NOTE: this function assumes that zft_last_vtbl points to a valid
 616  *  vtbl entry
 617  *
 618  *  NOTE: this routine always positions before the EOF marker
 619  */
 620 int zft_close_volume(zft_position *pos)
 621 {
 622         TRACE_FUN(ft_t_any);
 623
 624         if (zft_vtbl_empty || !zft_last_vtbl->open) { /* should not happen */
 625                 TRACE(ft_t_noise, "There are no volumes to finish");
 626                 TRACE_EXIT -EIO;
 627         }
 628         if (pos->seg_byte_pos == 0 &&
 629             pos->seg_pos != zft_last_vtbl->start_seg) {
 630                 pos->seg_pos --;
 631                 pos->seg_byte_pos      = zft_get_seg_sz(pos->seg_pos);
 632         }
 633         zft_last_vtbl->end_seg   = pos->seg_pos;
 634         zft_last_vtbl->size      = pos->volume_pos;
 635         zft_volume_table_changed = 1;
 636         zft_just_before_eof      = 1;
 637         zft_eom_vtbl->start_seg  = zft_last_vtbl->end_seg + 1;
 638         zft_last_vtbl->open      = 0; /* closed */
 639         TRACE_EXIT 0;
 640 }
 641
 642 /* write count file-marks at current position.
 643  *
 644  *  The tape is positioned after the eof-marker, that is at byte 0 of
 645  *  the segment following the eof-marker
 646  *
 647  *  this function is only allowed in zft_qic_mode
 648  *
 649  *  Only allowed when tape is at BOT or EOD.
 650  */
 651 int zft_weof(unsigned int count, zft_position *pos)
 652 {
 653
 654         TRACE_FUN(ft_t_flow);
 655
 656         if (!count) { /* write zero EOF marks should be a real no-op */
 657                 TRACE_EXIT 0;
 658         }
 659         zft_volume_table_changed = 1;
 660         if (zft_tape_at_lbot(pos)) {
 661                 zft_init_vtbl();
 662                 if(zft_old_ftape) {
 663                         /* clear old ftape's eof marks */
 664                         zft_clear_ftape_file_marks();
 665                         zft_old_ftape = 0;    /* no longer old ftape */
 666                 }
 667         }
 668         if (zft_last_vtbl->open) {
 669                 zft_close_volume(pos);
 670                 zft_move_past_eof(pos);
 671                 count --;
 672         }
 673         /* now it's easy, just append eof-marks, that is empty
 674          * volumes, to the end of the already recorded media.
 675          */
 676         while (count > 0 &&
 677                pos->seg_pos <= ft_last_data_segment &&
 678                zft_eom_vtbl->count < ZFT_MAX_VOLUMES) {
 679                 TRACE(ft_t_noise,
 680                       "Writing zero sized file at segment %d", pos->seg_pos);
 681                 zft_new_vtbl_entry();
 682                 zft_last_vtbl->start_seg       = pos->seg_pos;
 683                 zft_last_vtbl->end_seg         = pos->seg_pos;
 684                 zft_last_vtbl->size            = 0;
 685                 zft_last_vtbl->blk_sz          = zft_blk_sz;
 686                 zft_last_vtbl->zft_volume      = 1;
 687                 zft_last_vtbl->use_compression = 0;
 688                 pos->tape_pos += zft_get_seg_sz(pos->seg_pos);
 689                 zft_eom_vtbl->start_seg = ++ pos->seg_pos;
 690                 count --;
 691         }
 692         if (count > 0) {
 693                 /*  there are two possibilities: end of tape, or the
 694                  *  maximum number of files is exhausted.
 695                  */
 696                 zft_resid = count;
 697                 TRACE(ft_t_noise,"Number of marks NOT written: %d", zft_resid);
 698                 if (zft_eom_vtbl->count == ZFT_MAX_VOLUMES) {
 699                         TRACE_ABORT(-EINVAL, ft_t_warn,
 700                                     "maximum allowed number of files "
 701                                     "exhausted: %d", ZFT_MAX_VOLUMES);
 702                 } else {
 703                         TRACE_ABORT(-ENOSPC,
 704                                     ft_t_noise, "reached end of tape");
 705                 }
 706         }
 707         TRACE_EXIT 0;
 708 }
 709
 710 const zft_volinfo *zft_find_volume(unsigned int seg_pos)
 711 {
 712         TRACE_FUN(ft_t_flow);
 713
 714         TRACE(ft_t_any, "called with seg_pos %d",seg_pos);
 715         if (!zft_qic_mode) {
 716                 if (seg_pos > ft_last_data_segment) {
 717                         TRACE_EXIT &eot_vtbl;
 718                 }
 719                 tape_vtbl.blk_sz =  zft_blk_sz;
 720                 TRACE_EXIT &tape_vtbl;
 721         }
 722         if (seg_pos < zft_first_vtbl->start_seg) {
 723                 TRACE_EXIT (cur_vtbl = zft_first_vtbl);
 724         }
 725         while (seg_pos > cur_vtbl->end_seg) {
 726                 cur_vtbl = list_entry(cur_vtbl->node.next, zft_volinfo, node);
 727                 TRACE(ft_t_noise, "%d - %d", cur_vtbl->start_seg, cur_vtbl->end_seg);
 728         }
 729         while (seg_pos < cur_vtbl->start_seg) {
 730                 cur_vtbl = list_entry(cur_vtbl->node.prev, zft_volinfo, node);
 731                 TRACE(ft_t_noise, "%d - %d", cur_vtbl->start_seg, cur_vtbl->end_seg);
 732         }
 733         if (seg_pos > cur_vtbl->end_seg || seg_pos < cur_vtbl->start_seg) {
 734                 TRACE(ft_t_bug, "This cannot happen");
 735         }
 736         DUMP_VOLINFO(ft_t_noise, "", cur_vtbl);
 737         TRACE_EXIT cur_vtbl;
 738 }
 739
 740 /* this function really assumes that we are just before eof
 741  */
 742 void zft_move_past_eof(zft_position *pos)
 743 {
 744         TRACE_FUN(ft_t_flow);
 745
 746         TRACE(ft_t_noise, "old seg. pos: %d", pos->seg_pos);
 747         pos->tape_pos += zft_get_seg_sz(pos->seg_pos++) - pos->seg_byte_pos;
 748         pos->seg_byte_pos = 0;
 749         pos->volume_pos   = 0;
 750         if (zft_cmpr_ops) {
 751                 (*zft_cmpr_ops->reset)();
 752         }
 753         zft_just_before_eof =  0;
 754         zft_deblock_segment = -1; /* no need to cache it anymore */
 755         TRACE(ft_t_noise, "new seg. pos: %d", pos->seg_pos);
 756         TRACE_EXIT;
 757 }