fs/ntfs/lcnalloc.c

   1 /*
   2  * lcnalloc.c - Cluster (de)allocation code.  Part of the Linux-NTFS project.
   3  *
   4  * Copyright (c) 2004-2005 Anton Altaparmakov
   5  *
   6  * This program/include file is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as published
   8  * by the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program/include file is distributed in the hope that it will be
  12  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program (in the main directory of the Linux-NTFS
  18  * distribution in the file COPYING); if not, write to the Free Software
  19  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #ifdef NTFS_RW
  23
  24 #include <linux/pagemap.h>
  25
  26 #include "lcnalloc.h"
  27 #include "debug.h"
  28 #include "bitmap.h"
  29 #include "inode.h"
  30 #include "volume.h"
  31 #include "attrib.h"
  32 #include "malloc.h"
  33 #include "aops.h"
  34 #include "ntfs.h"
  35
  36 /**
  37  * ntfs_cluster_free_from_rl_nolock - free clusters from runlist
  38  * @vol:        mounted ntfs volume on which to free the clusters
  39  * @rl:         runlist describing the clusters to free
  40  *
  41  * Free all the clusters described by the runlist @rl on the volume @vol.  In
  42  * the case of an error being returned, at least some of the clusters were not
  43  * freed.
  44  *
  45  * Return 0 on success and -errno on error.
  46  *
  47  * Locking: - The volume lcn bitmap must be locked for writing on entry and is
  48  *            left locked on return.
  49  */
  50 int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  51                 const runlist_element *rl)
  52 {
  53         struct inode *lcnbmp_vi = vol->lcnbmp_ino;
  54         int ret = 0;
  55
  56         ntfs_debug("Entering.");
  57         if (!rl)
  58                 return 0;
  59         for (; rl->length; rl++) {
  60                 int err;
  61
  62                 if (rl->lcn < 0)
  63                         continue;
  64                 err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length);
  65                 if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err))
  66                         ret = err;
  67         }
  68         ntfs_debug("Done.");
  69         return ret;
  70 }
  71
  72 /**
  73  * ntfs_cluster_alloc - allocate clusters on an ntfs volume
  74  * @vol:        mounted ntfs volume on which to allocate the clusters
  75  * @start_vcn:  vcn to use for the first allocated cluster
  76  * @count:      number of clusters to allocate
  77  * @start_lcn:  starting lcn at which to allocate the clusters (or -1 if none)
  78  * @zone:       zone from which to allocate the clusters
  79  *
  80  * Allocate @count clusters preferably starting at cluster @start_lcn or at the
  81  * current allocator position if @start_lcn is -1, on the mounted ntfs volume
  82  * @vol. @zone is either DATA_ZONE for allocation of normal clusters or
  83  * MFT_ZONE for allocation of clusters for the master file table, i.e. the
  84  * $MFT/$DATA attribute.
  85  *
  86  * @start_vcn specifies the vcn of the first allocated cluster.  This makes
  87  * merging the resulting runlist with the old runlist easier.
  88  *
  89  * You need to check the return value with IS_ERR().  If this is false, the
  90  * function was successful and the return value is a runlist describing the
  91  * allocated cluster(s).  If IS_ERR() is true, the function failed and
  92  * PTR_ERR() gives you the error code.
  93  *
  94  * Notes on the allocation algorithm
  95  * =================================
  96  *
  97  * There are two data zones.  First is the area between the end of the mft zone
  98  * and the end of the volume, and second is the area between the start of the
  99  * volume and the start of the mft zone.  On unmodified/standard NTFS 1.x
 100  * volumes, the second data zone does not exist due to the mft zone being
 101  * expanded to cover the start of the volume in order to reserve space for the
 102  * mft bitmap attribute.
 103  *
 104  * This is not the prettiest function but the complexity stems from the need of
 105  * implementing the mft vs data zoned approach and from the fact that we have
 106  * access to the lcn bitmap in portions of up to 8192 bytes at a time, so we
 107  * need to cope with crossing over boundaries of two buffers.  Further, the
 108  * fact that the allocator allows for caller supplied hints as to the location
 109  * of where allocation should begin and the fact that the allocator keeps track
 110  * of where in the data zones the next natural allocation should occur,
 111  * contribute to the complexity of the function.  But it should all be
 112  * worthwhile, because this allocator should: 1) be a full implementation of
 113  * the MFT zone approach used by Windows NT, 2) cause reduction in
 114  * fragmentation, and 3) be speedy in allocations (the code is not optimized
 115  * for speed, but the algorithm is, so further speed improvements are probably
 116  * possible).
 117  *
 118  * FIXME: We should be monitoring cluster allocation and increment the MFT zone
 119  * size dynamically but this is something for the future.  We will just cause
 120  * heavier fragmentation by not doing it and I am not even sure Windows would
 121  * grow the MFT zone dynamically, so it might even be correct not to do this.
 122  * The overhead in doing dynamic MFT zone expansion would be very large and
 123  * unlikely worth the effort. (AIA)
 124  *
 125  * TODO: I have added in double the required zone position pointer wrap around
 126  * logic which can be optimized to having only one of the two logic sets.
 127  * However, having the double logic will work fine, but if we have only one of
 128  * the sets and we get it wrong somewhere, then we get into trouble, so
 129  * removing the duplicate logic requires _very_ careful consideration of _all_
 130  * possible code paths.  So at least for now, I am leaving the double logic -
 131  * better safe than sorry... (AIA)
 132  *
 133  * Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked
 134  *            on return.
 135  *          - This function takes the volume lcn bitmap lock for writing and
 136  *            modifies the bitmap contents.
 137  */
 138 runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
 139                 const s64 count, const LCN start_lcn,
 140                 const NTFS_CLUSTER_ALLOCATION_ZONES zone)
 141 {
 142         LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
 143         LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
 144         s64 clusters;
 145         loff_t i_size;
 146         struct inode *lcnbmp_vi;
 147         runlist_element *rl = NULL;
 148         struct address_space *mapping;
 149         struct page *page = NULL;
 150         u8 *buf, *byte;
 151         int err = 0, rlpos, rlsize, buf_size;
 152         u8 pass, done_zones, search_zone, need_writeback = 0, bit;
 153
 154         ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn "
 155                         "0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn,
 156                         (unsigned long long)count,
 157                         (unsigned long long)start_lcn,
 158                         zone == MFT_ZONE ? "MFT" : "DATA");
 159         BUG_ON(!vol);
 160         lcnbmp_vi = vol->lcnbmp_ino;
 161         BUG_ON(!lcnbmp_vi);
 162         BUG_ON(start_vcn < 0);
 163         BUG_ON(count < 0);
 164         BUG_ON(start_lcn < -1);
 165         BUG_ON(zone < FIRST_ZONE);
 166         BUG_ON(zone > LAST_ZONE);
 167
 168         /* Return NULL if @count is zero. */
 169         if (!count)
 170                 return NULL;
 171         /* Take the lcnbmp lock for writing. */
 172         down_write(&vol->lcnbmp_lock);
 173         /*
 174          * If no specific @start_lcn was requested, use the current data zone
 175          * position, otherwise use the requested @start_lcn but make sure it
 176          * lies outside the mft zone.  Also set done_zones to 0 (no zones done)
 177          * and pass depending on whether we are starting inside a zone (1) or
 178          * at the beginning of a zone (2).  If requesting from the MFT_ZONE,
 179          * we either start at the current position within the mft zone or at
 180          * the specified position.  If the latter is out of bounds then we start
 181          * at the beginning of the MFT_ZONE.
 182          */
 183         done_zones = 0;
 184         pass = 1;
 185         /*
 186          * zone_start and zone_end are the current search range.  search_zone
 187          * is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of
 188          * volume) and 4 for data zone 2 (start of volume till start of mft
 189          * zone).
 190          */
 191         zone_start = start_lcn;
 192         if (zone_start < 0) {
 193                 if (zone == DATA_ZONE)
 194                         zone_start = vol->data1_zone_pos;
 195                 else
 196                         zone_start = vol->mft_zone_pos;
 197                 if (!zone_start) {
 198                         /*
 199                          * Zone starts at beginning of volume which means a
 200                          * single pass is sufficient.
 201                          */
 202                         pass = 2;
 203                 }
 204         } else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start &&
 205                         zone_start < vol->mft_zone_end) {
 206                 zone_start = vol->mft_zone_end;
 207                 /*
 208                  * Starting at beginning of data1_zone which means a single
 209                  * pass in this zone is sufficient.
 210                  */
 211                 pass = 2;
 212         } else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start ||
 213                         zone_start >= vol->mft_zone_end)) {
 214                 zone_start = vol->mft_lcn;
 215                 if (!vol->mft_zone_end)
 216                         zone_start = 0;
 217                 /*
 218                  * Starting at beginning of volume which means a single pass
 219                  * is sufficient.
 220                  */
 221                 pass = 2;
 222         }
 223         if (zone == MFT_ZONE) {
 224                 zone_end = vol->mft_zone_end;
 225                 search_zone = 1;
 226         } else /* if (zone == DATA_ZONE) */ {
 227                 /* Skip searching the mft zone. */
 228                 done_zones |= 1;
 229                 if (zone_start >= vol->mft_zone_end) {
 230                         zone_end = vol->nr_clusters;
 231                         search_zone = 2;
 232                 } else {
 233                         zone_end = vol->mft_zone_start;
 234                         search_zone = 4;
 235                 }
 236         }
 237         /*
 238          * bmp_pos is the current bit position inside the bitmap.  We use
 239          * bmp_initial_pos to determine whether or not to do a zone switch.
 240          */
 241         bmp_pos = bmp_initial_pos = zone_start;
 242
 243         /* Loop until all clusters are allocated, i.e. clusters == 0. */
 244         clusters = count;
 245         rlpos = rlsize = 0;
 246         mapping = lcnbmp_vi->i_mapping;
 247         i_size = i_size_read(lcnbmp_vi);
 248         while (1) {
 249                 ntfs_debug("Start of outer while loop: done_zones 0x%x, "
 250                                 "search_zone %i, pass %i, zone_start 0x%llx, "
 251                                 "zone_end 0x%llx, bmp_initial_pos 0x%llx, "
 252                                 "bmp_pos 0x%llx, rlpos %i, rlsize %i.",
 253                                 done_zones, search_zone, pass,
 254                                 (unsigned long long)zone_start,
 255                                 (unsigned long long)zone_end,
 256                                 (unsigned long long)bmp_initial_pos,
 257                                 (unsigned long long)bmp_pos, rlpos, rlsize);
 258                 /* Loop until we run out of free clusters. */
 259                 last_read_pos = bmp_pos >> 3;
 260                 ntfs_debug("last_read_pos 0x%llx.",
 261                                 (unsigned long long)last_read_pos);
 262                 if (last_read_pos > i_size) {
 263                         ntfs_debug("End of attribute reached.  "
 264                                         "Skipping to zone_pass_done.");
 265                         goto zone_pass_done;
 266                 }
 267                 if (likely(page)) {
 268                         if (need_writeback) {
 269                                 ntfs_debug("Marking page dirty.");
 270                                 flush_dcache_page(page);
 271                                 set_page_dirty(page);
 272                                 need_writeback = 0;
 273                         }
 274                         ntfs_unmap_page(page);
 275                 }
 276                 page = ntfs_map_page(mapping, last_read_pos >>
 277                                 PAGE_CACHE_SHIFT);
 278                 if (IS_ERR(page)) {
 279                         err = PTR_ERR(page);
 280                         ntfs_error(vol->sb, "Failed to map page.");
 281                         goto out;
 282                 }
 283                 buf_size = last_read_pos & ~PAGE_CACHE_MASK;
 284                 buf = page_address(page) + buf_size;
 285                 buf_size = PAGE_CACHE_SIZE - buf_size;
 286                 if (unlikely(last_read_pos + buf_size > i_size))
 287                         buf_size = i_size - last_read_pos;
 288                 buf_size <<= 3;
 289                 lcn = bmp_pos & 7;
 290                 bmp_pos &= ~(LCN)7;
 291                 ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, "
 292                                 "bmp_pos 0x%llx, need_writeback %i.", buf_size,
 293                                 (unsigned long long)lcn,
 294                                 (unsigned long long)bmp_pos, need_writeback);
 295                 while (lcn < buf_size && lcn + bmp_pos < zone_end) {
 296                         byte = buf + (lcn >> 3);
 297                         ntfs_debug("In inner while loop: buf_size %i, "
 298                                         "lcn 0x%llx, bmp_pos 0x%llx, "
 299                                         "need_writeback %i, byte ofs 0x%x, "
 300                                         "*byte 0x%x.", buf_size,
 301                                         (unsigned long long)lcn,
 302                                         (unsigned long long)bmp_pos,
 303                                         need_writeback,
 304                                         (unsigned int)(lcn >> 3),
 305                                         (unsigned int)*byte);
 306                         /* Skip full bytes. */
 307                         if (*byte == 0xff) {
 308                                 lcn = (lcn + 8) & ~(LCN)7;
 309                                 ntfs_debug("Continuing while loop 1.");
 310                                 continue;
 311                         }
 312                         bit = 1 << (lcn & 7);
 313                         ntfs_debug("bit %i.", bit);
 314                         /* If the bit is already set, go onto the next one. */
 315                         if (*byte & bit) {
 316                                 lcn++;
 317                                 ntfs_debug("Continuing while loop 2.");
 318                                 continue;
 319                         }
 320                         /*
 321                          * Allocate more memory if needed, including space for
 322                          * the terminator element.
 323                          * ntfs_malloc_nofs() operates on whole pages only.
 324                          */
 325                         if ((rlpos + 2) * sizeof(*rl) > rlsize) {
 326                                 runlist_element *rl2;
 327
 328                                 ntfs_debug("Reallocating memory.");
 329                                 if (!rl)
 330                                         ntfs_debug("First free bit is at LCN "
 331                                                         "0x%llx.",
 332                                                         (unsigned long long)
 333                                                         (lcn + bmp_pos));
 334                                 rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
 335                                 if (unlikely(!rl2)) {
 336                                         err = -ENOMEM;
 337                                         ntfs_error(vol->sb, "Failed to "
 338                                                         "allocate memory.");
 339                                         goto out;
 340                                 }
 341                                 memcpy(rl2, rl, rlsize);
 342                                 ntfs_free(rl);
 343                                 rl = rl2;
 344                                 rlsize += PAGE_SIZE;
 345                                 ntfs_debug("Reallocated memory, rlsize 0x%x.",
 346                                                 rlsize);
 347                         }
 348                         /* Allocate the bitmap bit. */
 349                         *byte |= bit;
 350                         /* We need to write this bitmap page to disk. */
 351                         need_writeback = 1;
 352                         ntfs_debug("*byte 0x%x, need_writeback is set.",
 353                                         (unsigned int)*byte);
 354                         /*
 355                          * Coalesce with previous run if adjacent LCNs.
 356                          * Otherwise, append a new run.
 357                          */
 358                         ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), "
 359                                         "prev_lcn 0x%llx, lcn 0x%llx, "
 360                                         "bmp_pos 0x%llx, prev_run_len 0x%llx, "
 361                                         "rlpos %i.",
 362                                         (unsigned long long)(lcn + bmp_pos),
 363                                         1ULL, (unsigned long long)prev_lcn,
 364                                         (unsigned long long)lcn,
 365                                         (unsigned long long)bmp_pos,
 366                                         (unsigned long long)prev_run_len,
 367                                         rlpos);
 368                         if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
 369                                 ntfs_debug("Coalescing to run (lcn 0x%llx, "
 370                                                 "len 0x%llx).",
 371                                                 (unsigned long long)
 372                                                 rl[rlpos - 1].lcn,
 373                                                 (unsigned long long)
 374                                                 rl[rlpos - 1].length);
 375                                 rl[rlpos - 1].length = ++prev_run_len;
 376                                 ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), "
 377                                                 "prev_run_len 0x%llx.",
 378                                                 (unsigned long long)
 379                                                 rl[rlpos - 1].lcn,
 380                                                 (unsigned long long)
 381                                                 rl[rlpos - 1].length,
 382                                                 (unsigned long long)
 383                                                 prev_run_len);
 384                         } else {
 385                                 if (likely(rlpos)) {
 386                                         ntfs_debug("Adding new run, (previous "
 387                                                         "run lcn 0x%llx, "
 388                                                         "len 0x%llx).",
 389                                                         (unsigned long long)
 390                                                         rl[rlpos - 1].lcn,
 391                                                         (unsigned long long)
 392                                                         rl[rlpos - 1].length);
 393                                         rl[rlpos].vcn = rl[rlpos - 1].vcn +
 394                                                         prev_run_len;
 395                                 } else {
 396                                         ntfs_debug("Adding new run, is first "
 397                                                         "run.");
 398                                         rl[rlpos].vcn = start_vcn;
 399                                 }
 400                                 rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
 401                                 rl[rlpos].length = prev_run_len = 1;
 402                                 rlpos++;
 403                         }
 404                         /* Done? */
 405                         if (!--clusters) {
 406                                 LCN tc;
 407                                 /*
 408                                  * Update the current zone position.  Positions
 409                                  * of already scanned zones have been updated
 410                                  * during the respective zone switches.
 411                                  */
 412                                 tc = lcn + bmp_pos + 1;
 413                                 ntfs_debug("Done. Updating current zone "
 414                                                 "position, tc 0x%llx, "
 415                                                 "search_zone %i.",
 416                                                 (unsigned long long)tc,
 417                                                 search_zone);
 418                                 switch (search_zone) {
 419                                 case 1:
 420                                         ntfs_debug("Before checks, "
 421                                                         "vol->mft_zone_pos "
 422                                                         "0x%llx.",
 423                                                         (unsigned long long)
 424                                                         vol->mft_zone_pos);
 425                                         if (tc >= vol->mft_zone_end) {
 426                                                 vol->mft_zone_pos =
 427                                                                 vol->mft_lcn;
 428                                                 if (!vol->mft_zone_end)
 429                                                         vol->mft_zone_pos = 0;
 430                                         } else if ((bmp_initial_pos >=
 431                                                         vol->mft_zone_pos ||
 432                                                         tc > vol->mft_zone_pos)
 433                                                         && tc >= vol->mft_lcn)
 434                                                 vol->mft_zone_pos = tc;
 435                                         ntfs_debug("After checks, "
 436                                                         "vol->mft_zone_pos "
 437                                                         "0x%llx.",
 438                                                         (unsigned long long)
 439                                                         vol->mft_zone_pos);
 440                                         break;
 441                                 case 2:
 442                                         ntfs_debug("Before checks, "
 443                                                         "vol->data1_zone_pos "
 444                                                         "0x%llx.",
 445                                                         (unsigned long long)
 446                                                         vol->data1_zone_pos);
 447                                         if (tc >= vol->nr_clusters)
 448                                                 vol->data1_zone_pos =
 449                                                              vol->mft_zone_end;
 450                                         else if ((bmp_initial_pos >=
 451                                                     vol->data1_zone_pos ||
 452                                                     tc > vol->data1_zone_pos)
 453                                                     && tc >= vol->mft_zone_end)
 454                                                 vol->data1_zone_pos = tc;
 455                                         ntfs_debug("After checks, "
 456                                                         "vol->data1_zone_pos "
 457                                                         "0x%llx.",
 458                                                         (unsigned long long)
 459                                                         vol->data1_zone_pos);
 460                                         break;
 461                                 case 4:
 462                                         ntfs_debug("Before checks, "
 463                                                         "vol->data2_zone_pos "
 464                                                         "0x%llx.",
 465                                                         (unsigned long long)
 466                                                         vol->data2_zone_pos);
 467                                         if (tc >= vol->mft_zone_start)
 468                                                 vol->data2_zone_pos = 0;
 469                                         else if (bmp_initial_pos >=
 470                                                       vol->data2_zone_pos ||
 471                                                       tc > vol->data2_zone_pos)
 472                                                 vol->data2_zone_pos = tc;
 473                                         ntfs_debug("After checks, "
 474                                                         "vol->data2_zone_pos "
 475                                                         "0x%llx.",
 476                                                         (unsigned long long)
 477                                                         vol->data2_zone_pos);
 478                                         break;
 479                                 default:
 480                                         BUG();
 481                                 }
 482                                 ntfs_debug("Finished.  Going to out.");
 483                                 goto out;
 484                         }
 485                         lcn++;
 486                 }
 487                 bmp_pos += buf_size;
 488                 ntfs_debug("After inner while loop: buf_size 0x%x, lcn "
 489                                 "0x%llx, bmp_pos 0x%llx, need_writeback %i.",
 490                                 buf_size, (unsigned long long)lcn,
 491                                 (unsigned long long)bmp_pos, need_writeback);
 492                 if (bmp_pos < zone_end) {
 493                         ntfs_debug("Continuing outer while loop, "
 494                                         "bmp_pos 0x%llx, zone_end 0x%llx.",
 495                                         (unsigned long long)bmp_pos,
 496                                         (unsigned long long)zone_end);
 497                         continue;
 498                 }
 499 zone_pass_done: /* Finished with the current zone pass. */
 500                 ntfs_debug("At zone_pass_done, pass %i.", pass);
 501                 if (pass == 1) {
 502                         /*
 503                          * Now do pass 2, scanning the first part of the zone
 504                          * we omitted in pass 1.
 505                          */
 506                         pass = 2;
 507                         zone_end = zone_start;
 508                         switch (search_zone) {
 509                         case 1: /* mft_zone */
 510                                 zone_start = vol->mft_zone_start;
 511                                 break;
 512                         case 2: /* data1_zone */
 513                                 zone_start = vol->mft_zone_end;
 514                                 break;
 515                         case 4: /* data2_zone */
 516                                 zone_start = 0;
 517                                 break;
 518                         default:
 519                                 BUG();
 520                         }
 521                         /* Sanity check. */
 522                         if (zone_end < zone_start)
 523                                 zone_end = zone_start;
 524                         bmp_pos = zone_start;
 525                         ntfs_debug("Continuing outer while loop, pass 2, "
 526                                         "zone_start 0x%llx, zone_end 0x%llx, "
 527                                         "bmp_pos 0x%llx.",
 528                                         (unsigned long long)zone_start,
 529                                         (unsigned long long)zone_end,
 530                                         (unsigned long long)bmp_pos);
 531                         continue;
 532                 } /* pass == 2 */
 533 done_zones_check:
 534                 ntfs_debug("At done_zones_check, search_zone %i, done_zones "
 535                                 "before 0x%x, done_zones after 0x%x.",
 536                                 search_zone, done_zones,
 537                                 done_zones | search_zone);
 538                 done_zones |= search_zone;
 539                 if (done_zones < 7) {
 540                         ntfs_debug("Switching zone.");
 541                         /* Now switch to the next zone we haven't done yet. */
 542                         pass = 1;
 543                         switch (search_zone) {
 544                         case 1:
 545                                 ntfs_debug("Switching from mft zone to data1 "
 546                                                 "zone.");
 547                                 /* Update mft zone position. */
 548                                 if (rlpos) {
 549                                         LCN tc;
 550
 551                                         ntfs_debug("Before checks, "
 552                                                         "vol->mft_zone_pos "
 553                                                         "0x%llx.",
 554                                                         (unsigned long long)
 555                                                         vol->mft_zone_pos);
 556                                         tc = rl[rlpos - 1].lcn +
 557                                                         rl[rlpos - 1].length;
 558                                         if (tc >= vol->mft_zone_end) {
 559                                                 vol->mft_zone_pos =
 560                                                                 vol->mft_lcn;
 561                                                 if (!vol->mft_zone_end)
 562                                                         vol->mft_zone_pos = 0;
 563                                         } else if ((bmp_initial_pos >=
 564                                                         vol->mft_zone_pos ||
 565                                                         tc > vol->mft_zone_pos)
 566                                                         && tc >= vol->mft_lcn)
 567                                                 vol->mft_zone_pos = tc;
 568                                         ntfs_debug("After checks, "
 569                                                         "vol->mft_zone_pos "
 570                                                         "0x%llx.",
 571                                                         (unsigned long long)
 572                                                         vol->mft_zone_pos);
 573                                 }
 574                                 /* Switch from mft zone to data1 zone. */
 575 switch_to_data1_zone:           search_zone = 2;
 576                                 zone_start = bmp_initial_pos =
 577                                                 vol->data1_zone_pos;
 578                                 zone_end = vol->nr_clusters;
 579                                 if (zone_start == vol->mft_zone_end)
 580                                         pass = 2;
 581                                 if (zone_start >= zone_end) {
 582                                         vol->data1_zone_pos = zone_start =
 583                                                         vol->mft_zone_end;
 584                                         pass = 2;
 585                                 }
 586                                 break;
 587                         case 2:
 588                                 ntfs_debug("Switching from data1 zone to "
 589                                                 "data2 zone.");
 590                                 /* Update data1 zone position. */
 591                                 if (rlpos) {
 592                                         LCN tc;
 593
 594                                         ntfs_debug("Before checks, "
 595                                                         "vol->data1_zone_pos "
 596                                                         "0x%llx.",
 597                                                         (unsigned long long)
 598                                                         vol->data1_zone_pos);
 599                                         tc = rl[rlpos - 1].lcn +
 600                                                         rl[rlpos - 1].length;
 601                                         if (tc >= vol->nr_clusters)
 602                                                 vol->data1_zone_pos =
 603                                                              vol->mft_zone_end;
 604                                         else if ((bmp_initial_pos >=
 605                                                     vol->data1_zone_pos ||
 606                                                     tc > vol->data1_zone_pos)
 607                                                     && tc >= vol->mft_zone_end)
 608                                                 vol->data1_zone_pos = tc;
 609                                         ntfs_debug("After checks, "
 610                                                         "vol->data1_zone_pos "
 611                                                         "0x%llx.",
 612                                                         (unsigned long long)
 613                                                         vol->data1_zone_pos);
 614                                 }
 615                                 /* Switch from data1 zone to data2 zone. */
 616                                 search_zone = 4;
 617                                 zone_start = bmp_initial_pos =
 618                                                 vol->data2_zone_pos;
 619                                 zone_end = vol->mft_zone_start;
 620                                 if (!zone_start)
 621                                         pass = 2;
 622                                 if (zone_start >= zone_end) {
 623                                         vol->data2_zone_pos = zone_start =
 624                                                         bmp_initial_pos = 0;
 625                                         pass = 2;
 626                                 }
 627                                 break;
 628                         case 4:
 629                                 ntfs_debug("Switching from data2 zone to "
 630                                                 "data1 zone.");
 631                                 /* Update data2 zone position. */
 632                                 if (rlpos) {
 633                                         LCN tc;
 634
 635                                         ntfs_debug("Before checks, "
 636                                                         "vol->data2_zone_pos "
 637                                                         "0x%llx.",
 638                                                         (unsigned long long)
 639                                                         vol->data2_zone_pos);
 640                                         tc = rl[rlpos - 1].lcn +
 641                                                         rl[rlpos - 1].length;
 642                                         if (tc >= vol->mft_zone_start)
 643                                                 vol->data2_zone_pos = 0;
 644                                         else if (bmp_initial_pos >=
 645                                                       vol->data2_zone_pos ||
 646                                                       tc > vol->data2_zone_pos)
 647                                                 vol->data2_zone_pos = tc;
 648                                         ntfs_debug("After checks, "
 649                                                         "vol->data2_zone_pos "
 650                                                         "0x%llx.",
 651                                                         (unsigned long long)
 652                                                         vol->data2_zone_pos);
 653                                 }
 654                                 /* Switch from data2 zone to data1 zone. */
 655                                 goto switch_to_data1_zone;
 656                         default:
 657                                 BUG();
 658                         }
 659                         ntfs_debug("After zone switch, search_zone %i, "
 660                                         "pass %i, bmp_initial_pos 0x%llx, "
 661                                         "zone_start 0x%llx, zone_end 0x%llx.",
 662                                         search_zone, pass,
 663                                         (unsigned long long)bmp_initial_pos,
 664                                         (unsigned long long)zone_start,
 665                                         (unsigned long long)zone_end);
 666                         bmp_pos = zone_start;
 667                         if (zone_start == zone_end) {
 668                                 ntfs_debug("Empty zone, going to "
 669                                                 "done_zones_check.");
 670                                 /* Empty zone. Don't bother searching it. */
 671                                 goto done_zones_check;
 672                         }
 673                         ntfs_debug("Continuing outer while loop.");
 674                         continue;
 675                 } /* done_zones == 7 */
 676                 ntfs_debug("All zones are finished.");
 677                 /*
 678                  * All zones are finished!  If DATA_ZONE, shrink mft zone.  If
 679                  * MFT_ZONE, we have really run out of space.
 680                  */
 681                 mft_zone_size = vol->mft_zone_end - vol->mft_zone_start;
 682                 ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end "
 683                                 "0x%llx, mft_zone_size 0x%llx.",
 684                                 (unsigned long long)vol->mft_zone_start,
 685                                 (unsigned long long)vol->mft_zone_end,
 686                                 (unsigned long long)mft_zone_size);
 687                 if (zone == MFT_ZONE || mft_zone_size <= 0) {
 688                         ntfs_debug("No free clusters left, going to out.");
 689                         /* Really no more space left on device. */
 690                         err = -ENOSPC;
 691                         goto out;
 692                 } /* zone == DATA_ZONE && mft_zone_size > 0 */
 693                 ntfs_debug("Shrinking mft zone.");
 694                 zone_end = vol->mft_zone_end;
 695                 mft_zone_size >>= 1;
 696                 if (mft_zone_size > 0)
 697                         vol->mft_zone_end = vol->mft_zone_start + mft_zone_size;
 698                 else /* mft zone and data2 zone no longer exist. */
 699                         vol->data2_zone_pos = vol->mft_zone_start =
 700                                         vol->mft_zone_end = 0;
 701                 if (vol->mft_zone_pos >= vol->mft_zone_end) {
 702                         vol->mft_zone_pos = vol->mft_lcn;
 703                         if (!vol->mft_zone_end)
 704                                 vol->mft_zone_pos = 0;
 705                 }
 706                 bmp_pos = zone_start = bmp_initial_pos =
 707                                 vol->data1_zone_pos = vol->mft_zone_end;
 708                 search_zone = 2;
 709                 pass = 2;
 710                 done_zones &= ~2;
 711                 ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, "
 712                                 "vol->mft_zone_start 0x%llx, "
 713                                 "vol->mft_zone_end 0x%llx, "
 714                                 "vol->mft_zone_pos 0x%llx, search_zone 2, "
 715                                 "pass 2, dones_zones 0x%x, zone_start 0x%llx, "
 716                                 "zone_end 0x%llx, vol->data1_zone_pos 0x%llx, "
 717                                 "continuing outer while loop.",
 718                                 (unsigned long long)mft_zone_size,
 719                                 (unsigned long long)vol->mft_zone_start,
 720                                 (unsigned long long)vol->mft_zone_end,
 721                                 (unsigned long long)vol->mft_zone_pos,
 722                                 done_zones, (unsigned long long)zone_start,
 723                                 (unsigned long long)zone_end,
 724                                 (unsigned long long)vol->data1_zone_pos);
 725         }
 726         ntfs_debug("After outer while loop.");
 727 out:
 728         ntfs_debug("At out.");
 729         /* Add runlist terminator element. */
 730         if (likely(rl)) {
 731                 rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
 732                 rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
 733                 rl[rlpos].length = 0;
 734         }
 735         if (likely(page && !IS_ERR(page))) {
 736                 if (need_writeback) {
 737                         ntfs_debug("Marking page dirty.");
 738                         flush_dcache_page(page);
 739                         set_page_dirty(page);
 740                         need_writeback = 0;
 741                 }
 742                 ntfs_unmap_page(page);
 743         }
 744         if (likely(!err)) {
 745                 up_write(&vol->lcnbmp_lock);
 746                 ntfs_debug("Done.");
 747                 return rl;
 748         }
 749         ntfs_error(vol->sb, "Failed to allocate clusters, aborting "
 750                         "(error %i).", err);
 751         if (rl) {
 752                 int err2;
 753
 754                 if (err == -ENOSPC)
 755                         ntfs_debug("Not enough space to complete allocation, "
 756                                         "err -ENOSPC, first free lcn 0x%llx, "
 757                                         "could allocate up to 0x%llx "
 758                                         "clusters.",
 759                                         (unsigned long long)rl[0].lcn,
 760                                         (unsigned long long)(count - clusters));
 761                 /* Deallocate all allocated clusters. */
 762                 ntfs_debug("Attempting rollback...");
 763                 err2 = ntfs_cluster_free_from_rl_nolock(vol, rl);
 764                 if (err2) {
 765                         ntfs_error(vol->sb, "Failed to rollback (error %i).  "
 766                                         "Leaving inconsistent metadata!  "
 767                                         "Unmount and run chkdsk.", err2);
 768                         NVolSetErrors(vol);
 769                 }
 770                 /* Free the runlist. */
 771                 ntfs_free(rl);
 772         } else if (err == -ENOSPC)
 773                 ntfs_debug("No space left at all, err = -ENOSPC, first free "
 774                                 "lcn = 0x%llx.",
 775                                 (long long)vol->data1_zone_pos);
 776         up_write(&vol->lcnbmp_lock);
 777         return ERR_PTR(err);
 778 }
 779
 780 /**
 781  * __ntfs_cluster_free - free clusters on an ntfs volume
 782  * @ni:         ntfs inode whose runlist describes the clusters to free
 783  * @start_vcn:  vcn in the runlist of @ni at which to start freeing clusters
 784  * @count:      number of clusters to free or -1 for all clusters
 785  * @is_rollback:        true if this is a rollback operation
 786  *
 787  * Free @count clusters starting at the cluster @start_vcn in the runlist
 788  * described by the vfs inode @ni.
 789  *
 790  * If @count is -1, all clusters from @start_vcn to the end of the runlist are
 791  * deallocated.  Thus, to completely free all clusters in a runlist, use
 792  * @start_vcn = 0 and @count = -1.
 793  *
 794  * @is_rollback should always be FALSE, it is for internal use to rollback
 795  * errors.  You probably want to use ntfs_cluster_free() instead.
 796  *
 797  * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
 798  * has to deal with it later.
 799  *
 800  * Return the number of deallocated clusters (not counting sparse ones) on
 801  * success and -errno on error.
 802  *
 803  * Locking: - The runlist described by @ni must be locked for writing on entry
 804  *            and is locked on return.  Note the runlist may be modified when
 805  *            needed runlist fragments need to be mapped.
 806  *          - The volume lcn bitmap must be unlocked on entry and is unlocked
 807  *            on return.
 808  *          - This function takes the volume lcn bitmap lock for writing and
 809  *            modifies the bitmap contents.
 810  */
 811 s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
 812                 const BOOL is_rollback)
 813 {
 814         s64 delta, to_free, total_freed, real_freed;
 815         ntfs_volume *vol;
 816         struct inode *lcnbmp_vi;
 817         runlist_element *rl;
 818         int err;
 819
 820         BUG_ON(!ni);
 821         ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count "
 822                         "0x%llx.%s", ni->mft_no, (unsigned long long)start_vcn,
 823                         (unsigned long long)count,
 824                         is_rollback ? " (rollback)" : "");
 825         vol = ni->vol;
 826         lcnbmp_vi = vol->lcnbmp_ino;
 827         BUG_ON(!lcnbmp_vi);
 828         BUG_ON(start_vcn < 0);
 829         BUG_ON(count < -1);
 830         /*
 831          * Lock the lcn bitmap for writing but only if not rolling back.  We
 832          * must hold the lock all the way including through rollback otherwise
 833          * rollback is not possible because once we have cleared a bit and
 834          * dropped the lock, anyone could have set the bit again, thus
 835          * allocating the cluster for another use.
 836          */
 837         if (likely(!is_rollback))
 838                 down_write(&vol->lcnbmp_lock);
 839
 840         total_freed = real_freed = 0;
 841
 842         rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, NULL);
 843         if (IS_ERR(rl)) {
 844                 if (!is_rollback)
 845                         ntfs_error(vol->sb, "Failed to find first runlist "
 846                                         "element (error %li), aborting.",
 847                                         PTR_ERR(rl));
 848                 err = PTR_ERR(rl);
 849                 goto err_out;
 850         }
 851         if (unlikely(rl->lcn < LCN_HOLE)) {
 852                 if (!is_rollback)
 853                         ntfs_error(vol->sb, "First runlist element has "
 854                                         "invalid lcn, aborting.");
 855                 err = -EIO;
 856                 goto err_out;
 857         }
 858         /* Find the starting cluster inside the run that needs freeing. */
 859         delta = start_vcn - rl->vcn;
 860
 861         /* The number of clusters in this run that need freeing. */
 862         to_free = rl->length - delta;
 863         if (count >= 0 && to_free > count)
 864                 to_free = count;
 865
 866         if (likely(rl->lcn >= 0)) {
 867                 /* Do the actual freeing of the clusters in this run. */
 868                 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta,
 869                                 to_free, likely(!is_rollback) ? 0 : 1);
 870                 if (unlikely(err)) {
 871                         if (!is_rollback)
 872                                 ntfs_error(vol->sb, "Failed to clear first run "
 873                                                 "(error %i), aborting.", err);
 874                         goto err_out;
 875                 }
 876                 /* We have freed @to_free real clusters. */
 877                 real_freed = to_free;
 878         };
 879         /* Go to the next run and adjust the number of clusters left to free. */
 880         ++rl;
 881         if (count >= 0)
 882                 count -= to_free;
 883
 884         /* Keep track of the total "freed" clusters, including sparse ones. */
 885         total_freed = to_free;
 886         /*
 887          * Loop over the remaining runs, using @count as a capping value, and
 888          * free them.
 889          */
 890         for (; rl->length && count != 0; ++rl) {
 891                 if (unlikely(rl->lcn < LCN_HOLE)) {
 892                         VCN vcn;
 893
 894                         /* Attempt to map runlist. */
 895                         vcn = rl->vcn;
 896                         rl = ntfs_attr_find_vcn_nolock(ni, vcn, NULL);
 897                         if (IS_ERR(rl)) {
 898                                 err = PTR_ERR(rl);
 899                                 if (!is_rollback)
 900                                         ntfs_error(vol->sb, "Failed to map "
 901                                                         "runlist fragment or "
 902                                                         "failed to find "
 903                                                         "subsequent runlist "
 904                                                         "element.");
 905                                 goto err_out;
 906                         }
 907                         if (unlikely(rl->lcn < LCN_HOLE)) {
 908                                 if (!is_rollback)
 909                                         ntfs_error(vol->sb, "Runlist element "
 910                                                         "has invalid lcn "
 911                                                         "(0x%llx).",
 912                                                         (unsigned long long)
 913                                                         rl->lcn);
 914                                 err = -EIO;
 915                                 goto err_out;
 916                         }
 917                 }
 918                 /* The number of clusters in this run that need freeing. */
 919                 to_free = rl->length;
 920                 if (count >= 0 && to_free > count)
 921                         to_free = count;
 922
 923                 if (likely(rl->lcn >= 0)) {
 924                         /* Do the actual freeing of the clusters in the run. */
 925                         err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn,
 926                                         to_free, likely(!is_rollback) ? 0 : 1);
 927                         if (unlikely(err)) {
 928                                 if (!is_rollback)
 929                                         ntfs_error(vol->sb, "Failed to clear "
 930                                                         "subsequent run.");
 931                                 goto err_out;
 932                         }
 933                         /* We have freed @to_free real clusters. */
 934                         real_freed += to_free;
 935                 }
 936                 /* Adjust the number of clusters left to free. */
 937                 if (count >= 0)
 938                         count -= to_free;
 939
 940                 /* Update the total done clusters. */
 941                 total_freed += to_free;
 942         }
 943         if (likely(!is_rollback))
 944                 up_write(&vol->lcnbmp_lock);
 945
 946         BUG_ON(count > 0);
 947
 948         /* We are done.  Return the number of actually freed clusters. */
 949         ntfs_debug("Done.");
 950         return real_freed;
 951 err_out:
 952         if (is_rollback)
 953                 return err;
 954         /* If no real clusters were freed, no need to rollback. */
 955         if (!real_freed) {
 956                 up_write(&vol->lcnbmp_lock);
 957                 return err;
 958         }
 959         /*
 960          * Attempt to rollback and if that succeeds just return the error code.
 961          * If rollback fails, set the volume errors flag, emit an error
 962          * message, and return the error code.
 963          */
 964         delta = __ntfs_cluster_free(ni, start_vcn, total_freed, TRUE);
 965         if (delta < 0) {
 966                 ntfs_error(vol->sb, "Failed to rollback (error %i).  Leaving "
 967                                 "inconsistent metadata!  Unmount and run "
 968                                 "chkdsk.", (int)delta);
 969                 NVolSetErrors(vol);
 970         }
 971         up_write(&vol->lcnbmp_lock);
 972         ntfs_error(vol->sb, "Aborting (error %i).", err);
 973         return err;
 974 }
 975
 976 #endif /* NTFS_RW */