drivers/char/ftape/zftape/zftape-rw.c

   1 /*
   2  *      Copyright (C) 1996, 1997 Claus-Justus Heine
   3
   4  This program is free software; you can redistribute it and/or modify
   5  it under the terms of the GNU General Public License as published by
   6  the Free Software Foundation; either version 2, or (at your option)
   7  any later version.
   8
   9  This program is distributed in the hope that it will be useful,
  10  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  GNU 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, USA.
  17
  18  *
  19  * $Source: /homes/cvs/ftape-stacked/ftape/zftape/zftape-rw.c,v $
  20  * $Revision: 1.2 $
  21  * $Date: 1997/10/05 19:19:08 $
  22  *
  23  *      This file contains some common code for the r/w code for
  24  *      zftape.
  25  */
  26
  27 #include <linux/errno.h>
  28 #include <linux/mm.h>
  29
  30 #include <linux/zftape.h>
  31 #include "../zftape/zftape-init.h"
  32 #include "../zftape/zftape-eof.h"
  33 #include "../zftape/zftape-ctl.h"
  34 #include "../zftape/zftape-write.h"
  35 #include "../zftape/zftape-read.h"
  36 #include "../zftape/zftape-rw.h"
  37 #include "../zftape/zftape-vtbl.h"
  38
  39 /*      Global vars.
  40  */
  41
  42 __u8 *zft_deblock_buf;
  43 __u8 *zft_hseg_buf;
  44 int zft_deblock_segment = -1;
  45 zft_status_enum zft_io_state = zft_idle;
  46 int zft_header_changed;
  47 int zft_qic113; /* conform to old specs. and old zftape */
  48 int zft_use_compression;
  49 zft_position zft_pos = {
  50         -1, /* seg_pos */
  51         0,  /* seg_byte_pos */
  52         0,  /* tape_pos */
  53         0   /* volume_pos */
  54 };
  55 unsigned int zft_blk_sz = CONFIG_ZFT_DFLT_BLK_SZ;
  56 __s64 zft_capacity;
  57
  58 unsigned int zft_written_segments;
  59 int zft_label_changed;
  60
  61 /*      Local vars.
  62  */
  63
  64 unsigned int zft_get_seg_sz(unsigned int segment)
  65 {
  66         int size;
  67         TRACE_FUN(ft_t_any);
  68
  69         size = FT_SEGMENT_SIZE -
  70                 count_ones(ftape_get_bad_sector_entry(segment))*FT_SECTOR_SIZE;
  71         if (size > 0) {
  72                 TRACE_EXIT (unsigned)size;
  73         } else {
  74                 TRACE_EXIT 0;
  75         }
  76 }
  77
  78 /* ftape_set_flags(). Claus-Justus Heine, 1994/1995
  79  */
  80 void zft_set_flags(unsigned minor_unit)
  81 {
  82         TRACE_FUN(ft_t_flow);
  83
  84         zft_use_compression = zft_qic_mode = 0;
  85         switch (minor_unit & ZFT_MINOR_OP_MASK) {
  86         case (ZFT_Q80_MODE | ZFT_ZIP_MODE):
  87         case ZFT_ZIP_MODE:
  88                 zft_use_compression = 1;
  89         case 0:
  90         case ZFT_Q80_MODE:
  91                 zft_qic_mode = 1;
  92                 if (zft_mt_compression) { /* override the default */
  93                         zft_use_compression = 1;
  94                 }
  95                 break;
  96         case ZFT_RAW_MODE:
  97                 TRACE(ft_t_noise, "switching to raw mode");
  98                 break;
  99         default:
 100                 TRACE(ft_t_warn, "Warning:\n"
 101                       KERN_INFO "Wrong combination of minor device bits.\n"
 102                       KERN_INFO "Switching to raw read-only mode.");
 103                 zft_write_protected = 1;
 104                 break;
 105         }
 106         TRACE_EXIT;
 107 }
 108
 109 /* computes the segment and byte offset inside the segment
 110  * corresponding to tape_pos.
 111  *
 112  * tape_pos gives the offset in bytes from the beginning of the
 113  * ft_first_data_segment *seg_byte_pos is the offset in the current
 114  * segment in bytes
 115  *
 116  * Of, if this routine was called often one should cache the last data
 117  * pos it was called with, but actually this is only needed in
 118  * ftape_seek_block(), that is, almost never.
 119  */
 120 int zft_calc_seg_byte_coord(int *seg_byte_pos, __s64 tape_pos)
 121 {
 122         int segment;
 123         int seg_sz;
 124         TRACE_FUN(ft_t_flow);
 125
 126         if (tape_pos == 0) {
 127                 *seg_byte_pos = 0;
 128                 segment = ft_first_data_segment;
 129         } else {
 130                 seg_sz = 0;
 131
 132                 for (segment = ft_first_data_segment;
 133                      ((tape_pos > 0) && (segment <= ft_last_data_segment));
 134                      segment++) {
 135                         seg_sz = zft_get_seg_sz(segment);
 136                         tape_pos -= seg_sz;
 137                 }
 138                 if(tape_pos >= 0) {
 139                         /* the case tape_pos > != 0 means that the
 140                          * argument tape_pos lies beyond the EOT.
 141                          */
 142                         *seg_byte_pos= 0;
 143                 } else { /* tape_pos < 0 */
 144                         segment--;
 145                         *seg_byte_pos= tape_pos + seg_sz;
 146                 }
 147         }
 148         TRACE_EXIT(segment);
 149 }
 150
 151 /* ftape_calc_tape_pos().
 152  *
 153  * computes the offset in bytes from the beginning of the
 154  * ft_first_data_segment inverse to ftape_calc_seg_byte_coord
 155  *
 156  * We should do some caching. But how:
 157  *
 158  * Each time the header segments are read in, this routine is called
 159  * with ft_tracks_per_tape*segments_per_track argumnet. So this should be
 160  * the time to reset the cache.
 161  *
 162  * Also, it might be in the future that the bad sector map gets
 163  * changed.  -> reset the cache
 164  */
 165 static int seg_pos;
 166 static __s64 tape_pos;
 167
 168 __s64 zft_get_capacity(void)
 169 {
 170         seg_pos  = ft_first_data_segment;
 171         tape_pos = 0;
 172
 173         while (seg_pos <= ft_last_data_segment) {
 174                 tape_pos += zft_get_seg_sz(seg_pos ++);
 175         }
 176         return tape_pos;
 177 }
 178
 179 __s64 zft_calc_tape_pos(int segment)
 180 {
 181         int d1, d2, d3;
 182         TRACE_FUN(ft_t_any);
 183
 184         if (segment > ft_last_data_segment) {
 185                 TRACE_EXIT zft_capacity;
 186         }
 187         if (segment < ft_first_data_segment) {
 188                 TRACE_EXIT 0;
 189         }
 190         d2 = segment - seg_pos;
 191         if (-d2 > 10) {
 192                 d1 = segment - ft_first_data_segment;
 193                 if (-d2 > d1) {
 194                         tape_pos = 0;
 195                         seg_pos = ft_first_data_segment;
 196                         d2 = d1;
 197                 }
 198         }
 199         if (d2 > 10) {
 200                 d3 = ft_last_data_segment - segment;
 201                 if (d2 > d3) {
 202                         tape_pos = zft_capacity;
 203                         seg_pos  = ft_last_data_segment + 1;
 204                         d2 = -d3;
 205                 }
 206         }
 207         if (d2 > 0) {
 208                 while (seg_pos < segment) {
 209                         tape_pos +=  zft_get_seg_sz(seg_pos++);
 210                 }
 211         } else {
 212                 while (seg_pos > segment) {
 213                         tape_pos -=  zft_get_seg_sz(--seg_pos);
 214                 }
 215         }
 216         TRACE(ft_t_noise, "new cached pos: %d", seg_pos);
 217
 218         TRACE_EXIT tape_pos;
 219 }
 220
 221 /* copy Z-label string to buffer, keeps track of the correct offset in
 222  * `buffer'
 223  */
 224 void zft_update_label(__u8 *buffer)
 225 {
 226         TRACE_FUN(ft_t_flow);
 227
 228         if (strncmp(&buffer[FT_LABEL], ZFTAPE_LABEL,
 229                     sizeof(ZFTAPE_LABEL)-1) != 0) {
 230                 TRACE(ft_t_info, "updating label from \"%s\" to \"%s\"",
 231                       &buffer[FT_LABEL], ZFTAPE_LABEL);
 232                 strcpy(&buffer[FT_LABEL], ZFTAPE_LABEL);
 233                 memset(&buffer[FT_LABEL] + sizeof(ZFTAPE_LABEL) - 1, ' ',
 234                        FT_LABEL_SZ - sizeof(ZFTAPE_LABEL + 1));
 235                 PUT4(buffer, FT_LABEL_DATE, 0);
 236                 zft_label_changed = zft_header_changed = 1; /* changed */
 237         }
 238         TRACE_EXIT;
 239 }
 240
 241 int zft_verify_write_segments(unsigned int segment,
 242                               __u8 *data, size_t size,
 243                               __u8 *buffer)
 244 {
 245         int result;
 246         __u8 *write_buf;
 247         __u8 *src_buf;
 248         int single;
 249         int seg_pos;
 250         int seg_sz;
 251         int remaining;
 252         ft_write_mode_t write_mode;
 253         TRACE_FUN(ft_t_flow);
 254
 255         seg_pos   = segment;
 256         seg_sz    = zft_get_seg_sz(seg_pos);
 257         src_buf   = data;
 258         single    = size <= seg_sz;
 259         remaining = size;
 260         do {
 261                 TRACE(ft_t_noise, "\n"
 262                       KERN_INFO "remaining: %d\n"
 263                       KERN_INFO "seg_sz   : %d\n"
 264                       KERN_INFO "segment  : %d",
 265                       remaining, seg_sz, seg_pos);
 266                 if (remaining == seg_sz) {
 267                         write_buf = src_buf;
 268                         write_mode = single ? FT_WR_SINGLE : FT_WR_MULTI;
 269                         remaining = 0;
 270                 } else if (remaining > seg_sz) {
 271                         write_buf = src_buf;
 272                         write_mode = FT_WR_ASYNC; /* don't start tape */
 273                         remaining -= seg_sz;
 274                 } else { /* remaining < seg_sz */
 275                         write_buf = buffer;
 276                         memcpy(write_buf, src_buf, remaining);
 277                         memset(&write_buf[remaining],'\0',seg_sz-remaining);
 278                         write_mode = single ? FT_WR_SINGLE : FT_WR_MULTI;
 279                         remaining = 0;
 280                 }
 281                 if ((result = ftape_write_segment(seg_pos,
 282                                                   write_buf,
 283                                                   write_mode)) != seg_sz) {
 284                         TRACE(ft_t_err, "Error: "
 285                               "Couldn't write segment %d", seg_pos);
 286                         TRACE_EXIT result < 0 ? result : -EIO; /* bail out */
 287                 }
 288                 zft_written_segments ++;
 289                 seg_sz = zft_get_seg_sz(++seg_pos);
 290                 src_buf += result;
 291         } while (remaining > 0);
 292         if (ftape_get_status()->fti_state == writing) {
 293                 TRACE_CATCH(ftape_loop_until_writes_done(),);
 294                 TRACE_CATCH(ftape_abort_operation(),);
 295                 zft_prevent_flush();
 296         }
 297         seg_pos = segment;
 298         src_buf = data;
 299         remaining = size;
 300         do {
 301                 TRACE_CATCH(result = ftape_read_segment(seg_pos, buffer,
 302                                                         single ? FT_RD_SINGLE
 303                                                         : FT_RD_AHEAD),);
 304                 if (memcmp(src_buf, buffer,
 305                            remaining > result ? result : remaining) != 0) {
 306                         TRACE_ABORT(-EIO, ft_t_err,
 307                                     "Failed to verify written segment %d",
 308                                     seg_pos);
 309                 }
 310                 remaining -= result;
 311                 TRACE(ft_t_noise, "verify successful:\n"
 312                       KERN_INFO "segment  : %d\n"
 313                       KERN_INFO "segsize  : %d\n"
 314                       KERN_INFO "remaining: %d",
 315                       seg_pos, result, remaining);
 316                 src_buf   += seg_sz;
 317                 seg_pos++;
 318         } while (remaining > 0);
 319         TRACE_EXIT size;
 320 }
 321
 322
 323 /* zft_erase().  implemented compression-handling
 324  *
 325  * calculate the first data-segment when using/not using compression.
 326  *
 327  * update header-segment and compression-map-segment.
 328  */
 329 int zft_erase(void)
 330 {
 331         int result = 0;
 332         TRACE_FUN(ft_t_flow);
 333
 334         if (!zft_header_read) {
 335                 TRACE_CATCH(zft_vmalloc_once((void **)&zft_hseg_buf,
 336                                              FT_SEGMENT_SIZE),);
 337                 /* no need to read the vtbl and compression map */
 338                 TRACE_CATCH(ftape_read_header_segment(zft_hseg_buf),);
 339                 if ((zft_old_ftape =
 340                      zft_ftape_validate_label(&zft_hseg_buf[FT_LABEL]))) {
 341                         zft_ftape_extract_file_marks(zft_hseg_buf);
 342                 }
 343                 TRACE(ft_t_noise,
 344                       "ft_first_data_segment: %d, ft_last_data_segment: %d",
 345                       ft_first_data_segment, ft_last_data_segment);
 346                 zft_qic113 = (ft_format_code != fmt_normal &&
 347                               ft_format_code != fmt_1100ft &&
 348                               ft_format_code != fmt_425ft);
 349         }
 350         if (zft_old_ftape) {
 351                 zft_clear_ftape_file_marks();
 352                 zft_old_ftape = 0; /* no longer old ftape */
 353         }
 354         PUT2(zft_hseg_buf, FT_CMAP_START, 0);
 355         zft_volume_table_changed = 1;
 356         zft_capacity = zft_get_capacity();
 357         zft_init_vtbl();
 358         /* the rest must be done in ftape_update_header_segments
 359          */
 360         zft_header_read = 1;
 361         zft_header_changed = 1; /* force update of timestamp */
 362         result = zft_update_header_segments();
 363
 364         ftape_abort_operation();
 365
 366         zft_reset_position(&zft_pos);
 367         zft_set_flags (zft_unit);
 368         TRACE_EXIT result;
 369 }
 370
 371 unsigned int zft_get_time(void)
 372 {
 373         unsigned int date = FT_TIME_STAMP(2097, 11, 30, 23, 59, 59); /* fun */
 374         return date;
 375 }