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

   1 /*
   2  *      Copyright (C) 1996, 1997 Claus 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-write.c,v $
  20  * $Revision: 1.3 $
  21  * $Date: 1997/11/06 00:50:29 $
  22  *
  23  *      This file contains the writing code
  24  *      for the QIC-117 floppy-tape driver for Linux.
  25  */
  26
  27 #include <linux/errno.h>
  28 #include <linux/mm.h>
  29
  30 #include <linux/zftape.h>
  31
  32 #include <asm/uaccess.h>
  33
  34 #include "../zftape/zftape-init.h"
  35 #include "../zftape/zftape-eof.h"
  36 #include "../zftape/zftape-ctl.h"
  37 #include "../zftape/zftape-write.h"
  38 #include "../zftape/zftape-read.h"
  39 #include "../zftape/zftape-rw.h"
  40 #include "../zftape/zftape-vtbl.h"
  41
  42 /*      Global vars.
  43  */
  44
  45 /*      Local vars.
  46  */
  47 static int last_write_failed;
  48 static int need_flush;
  49
  50 void zft_prevent_flush(void)
  51 {
  52         need_flush = 0;
  53 }
  54
  55 static int zft_write_header_segments(__u8* buffer)
  56 {
  57         int header_1_ok = 0;
  58         int header_2_ok = 0;
  59         unsigned int time_stamp;
  60         TRACE_FUN(ft_t_noise);
  61
  62         TRACE_CATCH(ftape_abort_operation(),);
  63         ftape_seek_to_bot();    /* prevents extra rewind */
  64         if (GET4(buffer, 0) != FT_HSEG_MAGIC) {
  65                 TRACE_ABORT(-EIO, ft_t_err,
  66                             "wrong header signature found, aborting");
  67         }
  68         /*   Be optimistic: */
  69         PUT4(buffer, FT_SEG_CNT,
  70              zft_written_segments + GET4(buffer, FT_SEG_CNT) + 2);
  71         if ((time_stamp = zft_get_time()) != 0) {
  72                 PUT4(buffer, FT_WR_DATE, time_stamp);
  73                 if (zft_label_changed) {
  74                         PUT4(buffer, FT_LABEL_DATE, time_stamp);
  75                 }
  76         }
  77         TRACE(ft_t_noise,
  78               "writing first header segment %d", ft_header_segment_1);
  79         header_1_ok = zft_verify_write_segments(ft_header_segment_1,
  80                                                 buffer, FT_SEGMENT_SIZE,
  81                                                 zft_deblock_buf) >= 0;
  82         TRACE(ft_t_noise,
  83               "writing second header segment %d", ft_header_segment_2);
  84         header_2_ok = zft_verify_write_segments(ft_header_segment_2,
  85                                                 buffer, FT_SEGMENT_SIZE,
  86                                                 zft_deblock_buf) >= 0;
  87         if (!header_1_ok) {
  88                 TRACE(ft_t_warn, "Warning: "
  89                       "update of first header segment failed");
  90         }
  91         if (!header_2_ok) {
  92                 TRACE(ft_t_warn, "Warning: "
  93                       "update of second header segment failed");
  94         }
  95         if (!header_1_ok && !header_2_ok) {
  96                 TRACE_ABORT(-EIO, ft_t_err, "Error: "
  97                       "update of both header segments failed.");
  98         }
  99         TRACE_EXIT 0;
 100 }
 101
 102 int zft_update_header_segments(void)
 103 {
 104         TRACE_FUN(ft_t_noise);
 105
 106         /*  must NOT use zft_write_protected, as it also includes the
 107          *  file access mode. But we also want to update when soft
 108          *  write protection is enabled (O_RDONLY)
 109          */
 110         if (ft_write_protected || zft_old_ftape) {
 111                 TRACE_ABORT(0, ft_t_noise, "Tape set read-only: no update");
 112         }
 113         if (!zft_header_read) {
 114                 TRACE_ABORT(0, ft_t_noise, "Nothing to update");
 115         }
 116         if (!zft_header_changed) {
 117                 zft_header_changed = zft_written_segments > 0;
 118         }
 119         if (!zft_header_changed && !zft_volume_table_changed) {
 120                 TRACE_ABORT(0, ft_t_noise, "Nothing to update");
 121         }
 122         TRACE(ft_t_noise, "Updating header segments");
 123         if (ftape_get_status()->fti_state == writing) {
 124                 TRACE_CATCH(ftape_loop_until_writes_done(),);
 125         }
 126         TRACE_CATCH(ftape_abort_operation(),);
 127
 128         zft_deblock_segment = -1; /* invalidate the cache */
 129         if (zft_header_changed) {
 130                 TRACE_CATCH(zft_write_header_segments(zft_hseg_buf),);
 131         }
 132         if (zft_volume_table_changed) {
 133                 TRACE_CATCH(zft_update_volume_table(ft_first_data_segment),);
 134         }
 135         zft_header_changed =
 136                 zft_volume_table_changed =
 137                 zft_label_changed        =
 138                 zft_written_segments     = 0;
 139         TRACE_CATCH(ftape_abort_operation(),);
 140         ftape_seek_to_bot();
 141         TRACE_EXIT 0;
 142 }
 143
 144 static int read_merge_buffer(int seg_pos, __u8 *buffer, int offset, int seg_sz)
 145 {
 146         int result = 0;
 147         const ft_trace_t old_tracing = TRACE_LEVEL;
 148         TRACE_FUN(ft_t_flow);
 149
 150         if (zft_qic_mode) {
 151                 /*  writing in the middle of a volume is NOT allowed
 152                  *
 153                  */
 154                 TRACE(ft_t_noise, "No need to read a segment");
 155                 memset(buffer + offset, 0, seg_sz - offset);
 156                 TRACE_EXIT 0;
 157         }
 158         TRACE(ft_t_any, "waiting");
 159         ftape_start_writing(FT_WR_MULTI);
 160         TRACE_CATCH(ftape_loop_until_writes_done(),);
 161
 162         TRACE(ft_t_noise, "trying to read segment %d from offset %d",
 163               seg_pos, offset);
 164         SET_TRACE_LEVEL(ft_t_bug);
 165         result = zft_fetch_segment_fraction(seg_pos, buffer,
 166                                             FT_RD_SINGLE,
 167                                             offset, seg_sz - offset);
 168         SET_TRACE_LEVEL(old_tracing);
 169         if (result != (seg_sz - offset)) {
 170                 TRACE(ft_t_noise, "Ignore error: read_segment() result: %d",
 171                       result);
 172                 memset(buffer + offset, 0, seg_sz - offset);
 173         }
 174         TRACE_EXIT 0;
 175 }
 176
 177 /* flush the write buffer to tape and write an eof-marker at the
 178  * current position if not in raw mode.  This function always
 179  * positions the tape before the eof-marker.  _ftape_close() should
 180  * then advance to the next segment.
 181  *
 182  * the parameter "finish_volume" describes whether to position before
 183  * or after the possibly created file-mark. We always position after
 184  * the file-mark when called from ftape_close() and a flush was needed
 185  * (that is ftape_write() was the last tape operation before calling
 186  * ftape_flush) But we always position before the file-mark when this
 187  * function get's called from outside ftape_close()
 188  */
 189 int zft_flush_buffers(void)
 190 {
 191         int result;
 192         int data_remaining;
 193         int this_segs_size;
 194         TRACE_FUN(ft_t_flow);
 195
 196         TRACE(ft_t_data_flow,
 197               "entered, ftape_state = %d", ftape_get_status()->fti_state);
 198         if (ftape_get_status()->fti_state != writing && !need_flush) {
 199                 TRACE_ABORT(0, ft_t_noise, "no need for flush");
 200         }
 201         zft_io_state = zft_idle; /*  triggers some initializations for the
 202                                   *  read and write routines
 203                                   */
 204         if (last_write_failed) {
 205                 ftape_abort_operation();
 206                 TRACE_EXIT -EIO;
 207         }
 208         TRACE(ft_t_noise, "flushing write buffers");
 209         this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
 210         if (this_segs_size == zft_pos.seg_byte_pos) {
 211                 zft_pos.seg_pos ++;
 212                 data_remaining = zft_pos.seg_byte_pos = 0;
 213         } else {
 214                 data_remaining = zft_pos.seg_byte_pos;
 215         }
 216         /* If there is any data not written to tape yet, append zero's
 217          * up to the end of the sector (if using compression) or merge
 218          * it with the data existing on the tape Then write the
 219          * segment(s) to tape.
 220          */
 221         TRACE(ft_t_noise, "Position:\n"
 222               KERN_INFO "seg_pos  : %d\n"
 223               KERN_INFO "byte pos : %d\n"
 224               KERN_INFO "remaining: %d",
 225               zft_pos.seg_pos, zft_pos.seg_byte_pos, data_remaining);
 226         if (data_remaining > 0) {
 227                 do {
 228                         this_segs_size = zft_get_seg_sz(zft_pos.seg_pos);
 229                         if (this_segs_size > data_remaining) {
 230                                 TRACE_CATCH(read_merge_buffer(zft_pos.seg_pos,
 231                                                               zft_deblock_buf,
 232                                                               data_remaining,
 233                                                               this_segs_size),
 234                                             last_write_failed = 1);
 235                         }
 236                         result = ftape_write_segment(zft_pos.seg_pos,
 237                                                      zft_deblock_buf,
 238                                                      FT_WR_MULTI);
 239                         if (result != this_segs_size) {
 240                                 TRACE(ft_t_err, "flush buffers failed");
 241                                 zft_pos.tape_pos    -= zft_pos.seg_byte_pos;
 242                                 zft_pos.seg_byte_pos = 0;
 243
 244                                 last_write_failed = 1;
 245                                 TRACE_EXIT result;
 246                         }
 247                         zft_written_segments ++;
 248                         TRACE(ft_t_data_flow,
 249                               "flush, moved out buffer: %d", result);
 250                         /* need next segment for more data (empty segments?)
 251                          */
 252                         if (result < data_remaining) {
 253                                 if (result > 0) {
 254                                         /* move remainder to buffer beginning
 255                                          */
 256                                         memmove(zft_deblock_buf,
 257                                                 zft_deblock_buf + result,
 258                                                 FT_SEGMENT_SIZE - result);
 259                                 }
 260                         }
 261                         data_remaining -= result;
 262                         zft_pos.seg_pos ++;
 263                 } while (data_remaining > 0);
 264                 TRACE(ft_t_any, "result: %d", result);
 265                 zft_deblock_segment = --zft_pos.seg_pos;
 266                 if (data_remaining == 0) {  /* first byte next segment */
 267                         zft_pos.seg_byte_pos = this_segs_size;
 268                 } else { /* after data previous segment, data_remaining < 0 */
 269                         zft_pos.seg_byte_pos = data_remaining + result;
 270                 }
 271         } else {
 272                 TRACE(ft_t_noise, "zft_deblock_buf empty");
 273                 zft_pos.seg_pos --;
 274                 zft_pos.seg_byte_pos = zft_get_seg_sz (zft_pos.seg_pos);
 275                 ftape_start_writing(FT_WR_MULTI);
 276         }
 277         TRACE(ft_t_any, "waiting");
 278         if ((result = ftape_loop_until_writes_done()) < 0) {
 279                 /* that's really bad. What to to with zft_tape_pos?
 280                  */
 281                 TRACE(ft_t_err, "flush buffers failed");
 282         }
 283         TRACE(ft_t_any, "zft_seg_pos: %d, zft_seg_byte_pos: %d",
 284               zft_pos.seg_pos, zft_pos.seg_byte_pos);
 285         last_write_failed  =
 286                 need_flush = 0;
 287         TRACE_EXIT result;
 288 }
 289
 290 /* return-value: the number of bytes removed from the user-buffer
 291  *
 292  * out:
 293  *      int *write_cnt: how much actually has been moved to the
 294  *                      zft_deblock_buf
 295  *      int req_len  : MUST NOT BE CHANGED, except at EOT, in
 296  *                      which case it may be adjusted
 297  * in :
 298  *      char *buff        : the user buffer
 299  *      int buf_pos_write : copy of buf_len_wr int
 300  *      this_segs_size    : the size in bytes of the actual segment
 301  *                          char
 302  *      *zft_deblock_buf   : zft_deblock_buf
 303  */
 304 static int zft_simple_write(int *cnt,
 305                             __u8 *dst_buf, const int seg_sz,
 306                             const __u8 __user *src_buf, const int req_len,
 307                             const zft_position *pos,const zft_volinfo *volume)
 308 {
 309         int space_left;
 310         TRACE_FUN(ft_t_flow);
 311
 312         /* volume->size holds the tape capacity while volume is open */
 313         if (pos->tape_pos + volume->blk_sz > volume->size) {
 314                 TRACE_EXIT -ENOSPC;
 315         }
 316         /*  remaining space in this segment, NOT zft_deblock_buf
 317          */
 318         space_left = seg_sz - pos->seg_byte_pos;
 319         *cnt = req_len < space_left ? req_len : space_left;
 320         if (copy_from_user(dst_buf + pos->seg_byte_pos, src_buf, *cnt) != 0) {
 321                 TRACE_EXIT -EFAULT;
 322         }
 323         TRACE_EXIT *cnt;
 324 }
 325
 326 static int check_write_access(int req_len,
 327                               const zft_volinfo **volume,
 328                               zft_position *pos,
 329                               const unsigned int blk_sz)
 330 {
 331         int result;
 332         TRACE_FUN(ft_t_flow);
 333
 334         if ((req_len % zft_blk_sz) != 0) {
 335                 TRACE_ABORT(-EINVAL, ft_t_info,
 336                             "write-count %d must be multiple of block-size %d",
 337                             req_len, blk_sz);
 338         }
 339         if (zft_io_state == zft_writing) {
 340                 /*  all other error conditions have been checked earlier
 341                  */
 342                 TRACE_EXIT 0;
 343         }
 344         zft_io_state = zft_idle;
 345         TRACE_CATCH(zft_check_write_access(pos),);
 346         /*  If we haven't read the header segment yet, do it now.
 347          *  This will verify the configuration, get the bad sector
 348          *  table and read the volume table segment
 349          */
 350         if (!zft_header_read) {
 351                 TRACE_CATCH(zft_read_header_segments(),);
 352         }
 353         /*  fine. Now the tape is either at BOT or at EOD,
 354          *  Write start of volume now
 355          */
 356         TRACE_CATCH(zft_open_volume(pos, blk_sz, zft_use_compression),);
 357         *volume = zft_find_volume(pos->seg_pos);
 358         DUMP_VOLINFO(ft_t_noise, "", *volume);
 359         zft_just_before_eof = 0;
 360         /* now merge with old data if necessary */
 361         if (!zft_qic_mode && pos->seg_byte_pos != 0){
 362                 result = zft_fetch_segment(pos->seg_pos,
 363                                            zft_deblock_buf,
 364                                            FT_RD_SINGLE);
 365                 if (result < 0) {
 366                         if (result == -EINTR || result == -ENOSPC) {
 367                                 TRACE_EXIT result;
 368                         }
 369                         TRACE(ft_t_noise,
 370                               "ftape_read_segment() result: %d. "
 371                               "This might be normal when using "
 372                               "a newly\nformatted tape", result);
 373                         memset(zft_deblock_buf, '\0', pos->seg_byte_pos);
 374                 }
 375         }
 376         zft_io_state = zft_writing;
 377         TRACE_EXIT 0;
 378 }
 379
 380 static int fill_deblock_buf(__u8 *dst_buf, const int seg_sz,
 381                             zft_position *pos, const zft_volinfo *volume,
 382                             const char __user *usr_buf, const int req_len)
 383 {
 384         int cnt = 0;
 385         int result = 0;
 386         TRACE_FUN(ft_t_flow);
 387
 388         if (seg_sz == 0) {
 389                 TRACE_ABORT(0, ft_t_data_flow, "empty segment");
 390         }
 391         TRACE(ft_t_data_flow, "\n"
 392               KERN_INFO "remaining req_len: %d\n"
 393               KERN_INFO "          buf_pos: %d",
 394               req_len, pos->seg_byte_pos);
 395         /* zft_deblock_buf will not contain a valid segment any longer */
 396         zft_deblock_segment = -1;
 397         if (zft_use_compression) {
 398                 TRACE_CATCH(zft_cmpr_lock(1 /* try to load */),);
 399                 TRACE_CATCH(result= (*zft_cmpr_ops->write)(&cnt,
 400                                                            dst_buf, seg_sz,
 401                                                            usr_buf, req_len,
 402                                                            pos, volume),);
 403         } else {
 404                 TRACE_CATCH(result= zft_simple_write(&cnt,
 405                                                      dst_buf, seg_sz,
 406                                                      usr_buf, req_len,
 407                                                      pos, volume),);
 408         }
 409         pos->volume_pos   += result;
 410         pos->seg_byte_pos += cnt;
 411         pos->tape_pos     += cnt;
 412         TRACE(ft_t_data_flow, "\n"
 413               KERN_INFO "removed from user-buffer : %d bytes.\n"
 414               KERN_INFO "copied to zft_deblock_buf: %d bytes.\n"
 415               KERN_INFO "zft_tape_pos             : " LL_X " bytes.",
 416               result, cnt, LL(pos->tape_pos));
 417         TRACE_EXIT result;
 418 }
 419
 420
 421 /*  called by the kernel-interface routine "zft_write()"
 422  */
 423 int _zft_write(const char __user *buff, int req_len)
 424 {
 425         int result = 0;
 426         int written = 0;
 427         int write_cnt;
 428         int seg_sz;
 429         static const zft_volinfo *volume = NULL;
 430         TRACE_FUN(ft_t_flow);
 431
 432         zft_resid         = req_len;
 433         last_write_failed = 1; /* reset to 0 when successful */
 434         /* check if write is allowed
 435          */
 436         TRACE_CATCH(check_write_access(req_len, &volume,&zft_pos,zft_blk_sz),);
 437         while (req_len > 0) {
 438                 /* Allow us to escape from this loop with a signal !
 439                  */
 440                 FT_SIGNAL_EXIT(_DONT_BLOCK);
 441                 seg_sz = zft_get_seg_sz(zft_pos.seg_pos);
 442                 if ((write_cnt = fill_deblock_buf(zft_deblock_buf,
 443                                                   seg_sz,
 444                                                   &zft_pos,
 445                                                   volume,
 446                                                   buff,
 447                                                   req_len)) < 0) {
 448                         zft_resid -= written;
 449                         if (write_cnt == -ENOSPC) {
 450                                 /* leave the remainder to flush_buffers()
 451                                  */
 452                                 TRACE(ft_t_info, "No space left on device");
 453                                 last_write_failed = 0;
 454                                 if (!need_flush) {
 455                                         need_flush = written > 0;
 456                                 }
 457                                 TRACE_EXIT written > 0 ? written : -ENOSPC;
 458                         } else {
 459                                 TRACE_EXIT result;
 460                         }
 461                 }
 462                 if (zft_pos.seg_byte_pos == seg_sz) {
 463                         TRACE_CATCH(ftape_write_segment(zft_pos.seg_pos,
 464                                                         zft_deblock_buf,
 465                                                         FT_WR_ASYNC),
 466                                     zft_resid -= written);
 467                         zft_written_segments ++;
 468                         zft_pos.seg_byte_pos =  0;
 469                         zft_deblock_segment  = zft_pos.seg_pos;
 470                         ++zft_pos.seg_pos;
 471                 }
 472                 written += write_cnt;
 473                 buff    += write_cnt;
 474                 req_len -= write_cnt;
 475         } /* while (req_len > 0) */
 476         TRACE(ft_t_data_flow, "remaining in blocking buffer: %d",
 477                zft_pos.seg_byte_pos);
 478         TRACE(ft_t_data_flow, "just written bytes: %d", written);
 479         last_write_failed = 0;
 480         zft_resid -= written;
 481         need_flush = need_flush || written > 0;
 482         TRACE_EXIT written;               /* bytes written */
 483 }