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/config.h> /* for CONFIG_ZFT_DFLT_BLK_SZ */
  28 #include <linux/errno.h>
  29 #include <linux/mm.h>
  30
  31 #include <linux/zftape.h>
  32 #include "../zftape/zftape-init.h"
  33 #include "../zftape/zftape-eof.h"
  34 #include "../zftape/zftape-ctl.h"
  35 #include "../zftape/zftape-write.h"
  36 #include "../zftape/zftape-read.h"
  37 #include "../zftape/zftape-rw.h"
  38 #include "../zftape/zftape-vtbl.h"
  39
  40 /*      Global vars.
  41  */
  42
  43 __u8 *zft_deblock_buf;
  44 __u8 *zft_hseg_buf;
  45 int zft_deblock_segment = -1;
  46 zft_status_enum zft_io_state = zft_idle;
  47 int zft_header_changed;
  48 int zft_qic113; /* conform to old specs. and old zftape */
  49 int zft_use_compression;
  50 zft_position zft_pos = {
  51         -1, /* seg_pos */
  52         0,  /* seg_byte_pos */
  53         0,  /* tape_pos */
  54         0   /* volume_pos */
  55 };
  56 unsigned int zft_blk_sz = CONFIG_ZFT_DFLT_BLK_SZ;
  57 __s64 zft_capacity;
  58
  59 unsigned int zft_written_segments;
  60 int zft_label_changed;
  61
  62 /*      Local vars.
  63  */
  64
  65 unsigned int zft_get_seg_sz(unsigned int segment)
  66 {
  67         int size;
  68         TRACE_FUN(ft_t_any);
  69
  70         size = FT_SEGMENT_SIZE -
  71                 count_ones(ftape_get_bad_sector_entry(segment))*FT_SECTOR_SIZE;
  72         if (size > 0) {
  73                 TRACE_EXIT (unsigned)size;
  74         } else {
  75                 TRACE_EXIT 0;
  76         }
  77 }
  78
  79 /* ftape_set_flags(). Claus-Justus Heine, 1994/1995
  80  */
  81 void zft_set_flags(unsigned minor_unit)
  82 {
  83         TRACE_FUN(ft_t_flow);
  84
  85         zft_use_compression = zft_qic_mode = 0;
  86         switch (minor_unit & ZFT_MINOR_OP_MASK) {
  87         case (ZFT_Q80_MODE | ZFT_ZIP_MODE):
  88         case ZFT_ZIP_MODE:
  89                 zft_use_compression = 1;
  90         case 0:
  91         case ZFT_Q80_MODE:
  92                 zft_qic_mode = 1;
  93                 if (zft_mt_compression) { /* override the default */
  94                         zft_use_compression = 1;
  95                 }
  96                 break;
  97         case ZFT_RAW_MODE:
  98                 TRACE(ft_t_noise, "switching to raw mode");
  99                 break;
 100         default:
 101                 TRACE(ft_t_warn, "Warning:\n"
 102                       KERN_INFO "Wrong combination of minor device bits.\n"
 103                       KERN_INFO "Switching to raw read-only mode.");
 104                 zft_write_protected = 1;
 105                 break;
 106         }
 107         TRACE_EXIT;
 108 }
 109
 110 /* computes the segment and byte offset inside the segment
 111  * corresponding to tape_pos.
 112  *
 113  * tape_pos gives the offset in bytes from the beginning of the
 114  * ft_first_data_segment *seg_byte_pos is the offset in the current
 115  * segment in bytes
 116  *
 117  * Of, if this routine was called often one should cache the last data
 118  * pos it was called with, but actually this is only needed in
 119  * ftape_seek_block(), that is, almost never.
 120  */
 121 int zft_calc_seg_byte_coord(int *seg_byte_pos, __s64 tape_pos)
 122 {
 123         int segment;
 124         int seg_sz;
 125         TRACE_FUN(ft_t_flow);
 126
 127         if (tape_pos == 0) {
 128                 *seg_byte_pos = 0;
 129                 segment = ft_first_data_segment;
 130         } else {
 131                 seg_sz = 0;
 132
 133                 for (segment = ft_first_data_segment;
 134                      ((tape_pos > 0) && (segment <= ft_last_data_segment));
 135                      segment++) {
 136                         seg_sz = zft_get_seg_sz(segment);
 137                         tape_pos -= seg_sz;
 138                 }
 139                 if(tape_pos >= 0) {
 140                         /* the case tape_pos > != 0 means that the
 141                          * argument tape_pos lies beyond the EOT.
 142                          */
 143                         *seg_byte_pos= 0;
 144                 } else { /* tape_pos < 0 */
 145                         segment--;
 146                         *seg_byte_pos= tape_pos + seg_sz;
 147                 }
 148         }
 149         TRACE_EXIT(segment);
 150 }
 151
 152 /* ftape_calc_tape_pos().
 153  *
 154  * computes the offset in bytes from the beginning of the
 155  * ft_first_data_segment inverse to ftape_calc_seg_byte_coord
 156  *
 157  * We should do some caching. But how:
 158  *
 159  * Each time the header segments are read in, this routine is called
 160  * with ft_tracks_per_tape*segments_per_track argumnet. So this should be
 161  * the time to reset the cache.
 162  *
 163  * Also, it might be in the future that the bad sector map gets
 164  * changed.  -> reset the cache
 165  */
 166 static int seg_pos;
 167 static __s64 tape_pos;
 168
 169 __s64 zft_get_capacity(void)
 170 {
 171         seg_pos  = ft_first_data_segment;
 172         tape_pos = 0;
 173
 174         while (seg_pos <= ft_last_data_segment) {
 175                 tape_pos += zft_get_seg_sz(seg_pos ++);
 176         }
 177         return tape_pos;
 178 }
 179
 180 __s64 zft_calc_tape_pos(int segment)
 181 {
 182         int d1, d2, d3;
 183         TRACE_FUN(ft_t_any);
 184
 185         if (segment > ft_last_data_segment) {
 186                 TRACE_EXIT zft_capacity;
 187         }
 188         if (segment < ft_first_data_segment) {
 189                 TRACE_EXIT 0;
 190         }
 191         d2 = segment - seg_pos;
 192         if (-d2 > 10) {
 193                 d1 = segment - ft_first_data_segment;
 194                 if (-d2 > d1) {
 195                         tape_pos = 0;
 196                         seg_pos = ft_first_data_segment;
 197                         d2 = d1;
 198                 }
 199         }
 200         if (d2 > 10) {
 201                 d3 = ft_last_data_segment - segment;
 202                 if (d2 > d3) {
 203                         tape_pos = zft_capacity;
 204                         seg_pos  = ft_last_data_segment + 1;
 205                         d2 = -d3;
 206                 }
 207         }
 208         if (d2 > 0) {
 209                 while (seg_pos < segment) {
 210                         tape_pos +=  zft_get_seg_sz(seg_pos++);
 211                 }
 212         } else {
 213                 while (seg_pos > segment) {
 214                         tape_pos -=  zft_get_seg_sz(--seg_pos);
 215                 }
 216         }
 217         TRACE(ft_t_noise, "new cached pos: %d", seg_pos);
 218
 219         TRACE_EXIT tape_pos;
 220 }
 221
 222 /* copy Z-label string to buffer, keeps track of the correct offset in
 223  * `buffer'
 224  */
 225 void zft_update_label(__u8 *buffer)
 226 {
 227         TRACE_FUN(ft_t_flow);
 228
 229         if (strncmp(&buffer[FT_LABEL], ZFTAPE_LABEL,
 230                     sizeof(ZFTAPE_LABEL)-1) != 0) {
 231                 TRACE(ft_t_info, "updating label from \"%s\" to \"%s\"",
 232                       &buffer[FT_LABEL], ZFTAPE_LABEL);
 233                 strcpy(&buffer[FT_LABEL], ZFTAPE_LABEL);
 234                 memset(&buffer[FT_LABEL] + sizeof(ZFTAPE_LABEL) - 1, ' ',
 235                        FT_LABEL_SZ - sizeof(ZFTAPE_LABEL + 1));
 236                 PUT4(buffer, FT_LABEL_DATE, 0);
 237                 zft_label_changed = zft_header_changed = 1; /* changed */
 238         }
 239         TRACE_EXIT;
 240 }
 241
 242 int zft_verify_write_segments(unsigned int segment,
 243                               __u8 *data, size_t size,
 244                               __u8 *buffer)
 245 {
 246         int result;
 247         __u8 *write_buf;
 248         __u8 *src_buf;
 249         int single;
 250         int seg_pos;
 251         int seg_sz;
 252         int remaining;
 253         ft_write_mode_t write_mode;
 254         TRACE_FUN(ft_t_flow);
 255
 256         seg_pos   = segment;
 257         seg_sz    = zft_get_seg_sz(seg_pos);
 258         src_buf   = data;
 259         single    = size <= seg_sz;
 260         remaining = size;
 261         do {
 262                 TRACE(ft_t_noise, "\n"
 263                       KERN_INFO "remaining: %d\n"
 264                       KERN_INFO "seg_sz   : %d\n"
 265                       KERN_INFO "segment  : %d",
 266                       remaining, seg_sz, seg_pos);
 267                 if (remaining == seg_sz) {
 268                         write_buf = src_buf;
 269                         write_mode = single ? FT_WR_SINGLE : FT_WR_MULTI;
 270                         remaining = 0;
 271                 } else if (remaining > seg_sz) {
 272                         write_buf = src_buf;
 273                         write_mode = FT_WR_ASYNC; /* don't start tape */
 274                         remaining -= seg_sz;
 275                 } else { /* remaining < seg_sz */
 276                         write_buf = buffer;
 277                         memcpy(write_buf, src_buf, remaining);
 278                         memset(&write_buf[remaining],'\0',seg_sz-remaining);
 279                         write_mode = single ? FT_WR_SINGLE : FT_WR_MULTI;
 280                         remaining = 0;
 281                 }
 282                 if ((result = ftape_write_segment(seg_pos,
 283                                                   write_buf,
 284                                                   write_mode)) != seg_sz) {
 285                         TRACE(ft_t_err, "Error: "
 286                               "Couldn't write segment %d", seg_pos);
 287                         TRACE_EXIT result < 0 ? result : -EIO; /* bail out */
 288                 }
 289                 zft_written_segments ++;
 290                 seg_sz = zft_get_seg_sz(++seg_pos);
 291                 src_buf += result;
 292         } while (remaining > 0);
 293         if (ftape_get_status()->fti_state == writing) {
 294                 TRACE_CATCH(ftape_loop_until_writes_done(),);
 295                 TRACE_CATCH(ftape_abort_operation(),);
 296                 zft_prevent_flush();
 297         }
 298         seg_pos = segment;
 299         src_buf = data;
 300         remaining = size;
 301         do {
 302                 TRACE_CATCH(result = ftape_read_segment(seg_pos, buffer,
 303                                                         single ? FT_RD_SINGLE
 304                                                         : FT_RD_AHEAD),);
 305                 if (memcmp(src_buf, buffer,
 306                            remaining > result ? result : remaining) != 0) {
 307                         TRACE_ABORT(-EIO, ft_t_err,
 308                                     "Failed to verify written segment %d",
 309                                     seg_pos);
 310                 }
 311                 remaining -= result;
 312                 TRACE(ft_t_noise, "verify successful:\n"
 313                       KERN_INFO "segment  : %d\n"
 314                       KERN_INFO "segsize  : %d\n"
 315                       KERN_INFO "remaining: %d",
 316                       seg_pos, result, remaining);
 317                 src_buf   += seg_sz;
 318                 seg_pos++;
 319         } while (remaining > 0);
 320         TRACE_EXIT size;
 321 }
 322
 323
 324 /* zft_erase().  implemented compression-handling
 325  *
 326  * calculate the first data-segment when using/not using compression.
 327  *
 328  * update header-segment and compression-map-segment.
 329  */
 330 int zft_erase(void)
 331 {
 332         int result = 0;
 333         TRACE_FUN(ft_t_flow);
 334
 335         if (!zft_header_read) {
 336                 TRACE_CATCH(zft_vmalloc_once((void **)&zft_hseg_buf,
 337                                              FT_SEGMENT_SIZE),);
 338                 /* no need to read the vtbl and compression map */
 339                 TRACE_CATCH(ftape_read_header_segment(zft_hseg_buf),);
 340                 if ((zft_old_ftape =
 341                      zft_ftape_validate_label(&zft_hseg_buf[FT_LABEL]))) {
 342                         zft_ftape_extract_file_marks(zft_hseg_buf);
 343                 }
 344                 TRACE(ft_t_noise,
 345                       "ft_first_data_segment: %d, ft_last_data_segment: %d",
 346                       ft_first_data_segment, ft_last_data_segment);
 347                 zft_qic113 = (ft_format_code != fmt_normal &&
 348                               ft_format_code != fmt_1100ft &&
 349                               ft_format_code != fmt_425ft);
 350         }
 351         if (zft_old_ftape) {
 352                 zft_clear_ftape_file_marks();
 353                 zft_old_ftape = 0; /* no longer old ftape */
 354         }
 355         PUT2(zft_hseg_buf, FT_CMAP_START, 0);
 356         zft_volume_table_changed = 1;
 357         zft_capacity = zft_get_capacity();
 358         zft_init_vtbl();
 359         /* the rest must be done in ftape_update_header_segments
 360          */
 361         zft_header_read = 1;
 362         zft_header_changed = 1; /* force update of timestamp */
 363         result = zft_update_header_segments();
 364
 365         ftape_abort_operation();
 366
 367         zft_reset_position(&zft_pos);
 368         zft_set_flags (zft_unit);
 369         TRACE_EXIT result;
 370 }
 371
 372 unsigned int zft_get_time(void)
 373 {
 374         unsigned int date = FT_TIME_STAMP(2097, 11, 30, 23, 59, 59); /* fun */
 375         return date;
 376 }