fs/ocfs2/localalloc.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * localalloc.c
   5  *
   6  * Node local data allocation
   7  *
   8  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #include <linux/fs.h>
  27 #include <linux/types.h>
  28 #include <linux/slab.h>
  29 #include <linux/highmem.h>
  30 #include <linux/bitops.h>
  31
  32 #define MLOG_MASK_PREFIX ML_DISK_ALLOC
  33 #include <cluster/masklog.h>
  34
  35 #include "ocfs2.h"
  36
  37 #include "alloc.h"
  38 #include "dlmglue.h"
  39 #include "inode.h"
  40 #include "journal.h"
  41 #include "localalloc.h"
  42 #include "suballoc.h"
  43 #include "super.h"
  44 #include "sysfile.h"
  45
  46 #include "buffer_head_io.h"
  47
  48 #define OCFS2_LOCAL_ALLOC(dinode)       (&((dinode)->id2.i_lab))
  49
  50 static inline int ocfs2_local_alloc_window_bits(struct ocfs2_super *osb);
  51
  52 static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc);
  53
  54 static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
  55                                              struct ocfs2_dinode *alloc,
  56                                              u32 numbits);
  57
  58 static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc);
  59
  60 static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
  61                                     struct ocfs2_journal_handle *handle,
  62                                     struct ocfs2_dinode *alloc,
  63                                     struct inode *main_bm_inode,
  64                                     struct buffer_head *main_bm_bh);
  65
  66 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
  67                                                 struct ocfs2_journal_handle *handle,
  68                                                 struct ocfs2_alloc_context **ac,
  69                                                 struct inode **bitmap_inode,
  70                                                 struct buffer_head **bitmap_bh);
  71
  72 static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
  73                                         struct ocfs2_journal_handle *handle,
  74                                         struct ocfs2_alloc_context *ac);
  75
  76 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
  77                                           struct inode *local_alloc_inode);
  78
  79 /*
  80  * Determine how large our local alloc window should be, in bits.
  81  *
  82  * These values (and the behavior in ocfs2_alloc_should_use_local) have
  83  * been chosen so that most allocations, including new block groups go
  84  * through local alloc.
  85  */
  86 static inline int ocfs2_local_alloc_window_bits(struct ocfs2_super *osb)
  87 {
  88         BUG_ON(osb->s_clustersize_bits < 12);
  89
  90         return 2048 >> (osb->s_clustersize_bits - 12);
  91 }
  92
  93 /*
  94  * Tell us whether a given allocation should use the local alloc
  95  * file. Otherwise, it has to go to the main bitmap.
  96  */
  97 int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
  98 {
  99         int la_bits = ocfs2_local_alloc_window_bits(osb);
 100
 101         if (osb->local_alloc_state != OCFS2_LA_ENABLED)
 102                 return 0;
 103
 104         /* la_bits should be at least twice the size (in clusters) of
 105          * a new block group. We want to be sure block group
 106          * allocations go through the local alloc, so allow an
 107          * allocation to take up to half the bitmap. */
 108         if (bits > (la_bits / 2))
 109                 return 0;
 110
 111         return 1;
 112 }
 113
 114 int ocfs2_load_local_alloc(struct ocfs2_super *osb)
 115 {
 116         int status = 0;
 117         struct ocfs2_dinode *alloc = NULL;
 118         struct buffer_head *alloc_bh = NULL;
 119         u32 num_used;
 120         struct inode *inode = NULL;
 121         struct ocfs2_local_alloc *la;
 122
 123         mlog_entry_void();
 124
 125         /* read the alloc off disk */
 126         inode = ocfs2_get_system_file_inode(osb, LOCAL_ALLOC_SYSTEM_INODE,
 127                                             osb->slot_num);
 128         if (!inode) {
 129                 status = -EINVAL;
 130                 mlog_errno(status);
 131                 goto bail;
 132         }
 133
 134         status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno,
 135                                   &alloc_bh, 0, inode);
 136         if (status < 0) {
 137                 mlog_errno(status);
 138                 goto bail;
 139         }
 140
 141         alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
 142         la = OCFS2_LOCAL_ALLOC(alloc);
 143
 144         if (!(le32_to_cpu(alloc->i_flags) &
 145             (OCFS2_LOCAL_ALLOC_FL|OCFS2_BITMAP_FL))) {
 146                 mlog(ML_ERROR, "Invalid local alloc inode, %llu\n",
 147                      (unsigned long long)OCFS2_I(inode)->ip_blkno);
 148                 status = -EINVAL;
 149                 goto bail;
 150         }
 151
 152         if ((la->la_size == 0) ||
 153             (le16_to_cpu(la->la_size) > ocfs2_local_alloc_size(inode->i_sb))) {
 154                 mlog(ML_ERROR, "Local alloc size is invalid (la_size = %u)\n",
 155                      le16_to_cpu(la->la_size));
 156                 status = -EINVAL;
 157                 goto bail;
 158         }
 159
 160         /* do a little verification. */
 161         num_used = ocfs2_local_alloc_count_bits(alloc);
 162
 163         /* hopefully the local alloc has always been recovered before
 164          * we load it. */
 165         if (num_used
 166             || alloc->id1.bitmap1.i_used
 167             || alloc->id1.bitmap1.i_total
 168             || la->la_bm_off)
 169                 mlog(ML_ERROR, "Local alloc hasn't been recovered!\n"
 170                      "found = %u, set = %u, taken = %u, off = %u\n",
 171                      num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
 172                      le32_to_cpu(alloc->id1.bitmap1.i_total),
 173                      OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
 174
 175         osb->local_alloc_bh = alloc_bh;
 176         osb->local_alloc_state = OCFS2_LA_ENABLED;
 177
 178 bail:
 179         if (status < 0)
 180                 if (alloc_bh)
 181                         brelse(alloc_bh);
 182         if (inode)
 183                 iput(inode);
 184
 185         mlog_exit(status);
 186         return status;
 187 }
 188
 189 /*
 190  * return any unused bits to the bitmap and write out a clean
 191  * local_alloc.
 192  *
 193  * local_alloc_bh is optional. If not passed, we will simply use the
 194  * one off osb. If you do pass it however, be warned that it *will* be
 195  * returned brelse'd and NULL'd out.*/
 196 void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
 197 {
 198         int status;
 199         struct ocfs2_journal_handle *handle = NULL;
 200         struct inode *local_alloc_inode = NULL;
 201         struct buffer_head *bh = NULL;
 202         struct buffer_head *main_bm_bh = NULL;
 203         struct inode *main_bm_inode = NULL;
 204         struct ocfs2_dinode *alloc_copy = NULL;
 205         struct ocfs2_dinode *alloc = NULL;
 206
 207         mlog_entry_void();
 208
 209         if (osb->local_alloc_state == OCFS2_LA_UNUSED)
 210                 goto bail;
 211
 212         local_alloc_inode =
 213                 ocfs2_get_system_file_inode(osb,
 214                                             LOCAL_ALLOC_SYSTEM_INODE,
 215                                             osb->slot_num);
 216         if (!local_alloc_inode) {
 217                 status = -ENOENT;
 218                 mlog_errno(status);
 219                 goto bail;
 220         }
 221
 222         osb->local_alloc_state = OCFS2_LA_DISABLED;
 223
 224         handle = ocfs2_alloc_handle(osb);
 225         if (!handle) {
 226                 status = -ENOMEM;
 227                 mlog_errno(status);
 228                 goto bail;
 229         }
 230
 231         main_bm_inode = ocfs2_get_system_file_inode(osb,
 232                                                     GLOBAL_BITMAP_SYSTEM_INODE,
 233                                                     OCFS2_INVALID_SLOT);
 234         if (!main_bm_inode) {
 235                 status = -EINVAL;
 236                 mlog_errno(status);
 237                 goto bail;
 238         }
 239
 240         ocfs2_handle_add_inode(handle, main_bm_inode);
 241         status = ocfs2_meta_lock(main_bm_inode, handle, &main_bm_bh, 1);
 242         if (status < 0) {
 243                 mlog_errno(status);
 244                 goto bail;
 245         }
 246
 247         /* WINDOW_MOVE_CREDITS is a bit heavy... */
 248         handle = ocfs2_start_trans(osb, handle, OCFS2_WINDOW_MOVE_CREDITS);
 249         if (IS_ERR(handle)) {
 250                 mlog_errno(PTR_ERR(handle));
 251                 handle = NULL;
 252                 goto bail;
 253         }
 254
 255         bh = osb->local_alloc_bh;
 256         alloc = (struct ocfs2_dinode *) bh->b_data;
 257
 258         alloc_copy = kmalloc(bh->b_size, GFP_KERNEL);
 259         if (!alloc_copy) {
 260                 status = -ENOMEM;
 261                 goto bail;
 262         }
 263         memcpy(alloc_copy, alloc, bh->b_size);
 264
 265         status = ocfs2_journal_access(handle, local_alloc_inode, bh,
 266                                       OCFS2_JOURNAL_ACCESS_WRITE);
 267         if (status < 0) {
 268                 mlog_errno(status);
 269                 goto bail;
 270         }
 271
 272         ocfs2_clear_local_alloc(alloc);
 273
 274         status = ocfs2_journal_dirty(handle, bh);
 275         if (status < 0) {
 276                 mlog_errno(status);
 277                 goto bail;
 278         }
 279
 280         brelse(bh);
 281         osb->local_alloc_bh = NULL;
 282         osb->local_alloc_state = OCFS2_LA_UNUSED;
 283
 284         status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
 285                                           main_bm_inode, main_bm_bh);
 286         if (status < 0)
 287                 mlog_errno(status);
 288
 289 bail:
 290         if (handle)
 291                 ocfs2_commit_trans(handle);
 292
 293         if (main_bm_bh)
 294                 brelse(main_bm_bh);
 295
 296         if (main_bm_inode)
 297                 iput(main_bm_inode);
 298
 299         if (local_alloc_inode)
 300                 iput(local_alloc_inode);
 301
 302         if (alloc_copy)
 303                 kfree(alloc_copy);
 304
 305         mlog_exit_void();
 306 }
 307
 308 /*
 309  * We want to free the bitmap bits outside of any recovery context as
 310  * we'll need a cluster lock to do so, but we must clear the local
 311  * alloc before giving up the recovered nodes journal. To solve this,
 312  * we kmalloc a copy of the local alloc before it's change for the
 313  * caller to process with ocfs2_complete_local_alloc_recovery
 314  */
 315 int ocfs2_begin_local_alloc_recovery(struct ocfs2_super *osb,
 316                                      int slot_num,
 317                                      struct ocfs2_dinode **alloc_copy)
 318 {
 319         int status = 0;
 320         struct buffer_head *alloc_bh = NULL;
 321         struct inode *inode = NULL;
 322         struct ocfs2_dinode *alloc;
 323
 324         mlog_entry("(slot_num = %d)\n", slot_num);
 325
 326         *alloc_copy = NULL;
 327
 328         inode = ocfs2_get_system_file_inode(osb,
 329                                             LOCAL_ALLOC_SYSTEM_INODE,
 330                                             slot_num);
 331         if (!inode) {
 332                 status = -EINVAL;
 333                 mlog_errno(status);
 334                 goto bail;
 335         }
 336
 337         mutex_lock(&inode->i_mutex);
 338
 339         status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno,
 340                                   &alloc_bh, 0, inode);
 341         if (status < 0) {
 342                 mlog_errno(status);
 343                 goto bail;
 344         }
 345
 346         *alloc_copy = kmalloc(alloc_bh->b_size, GFP_KERNEL);
 347         if (!(*alloc_copy)) {
 348                 status = -ENOMEM;
 349                 goto bail;
 350         }
 351         memcpy((*alloc_copy), alloc_bh->b_data, alloc_bh->b_size);
 352
 353         alloc = (struct ocfs2_dinode *) alloc_bh->b_data;
 354         ocfs2_clear_local_alloc(alloc);
 355
 356         status = ocfs2_write_block(osb, alloc_bh, inode);
 357         if (status < 0)
 358                 mlog_errno(status);
 359
 360 bail:
 361         if ((status < 0) && (*alloc_copy)) {
 362                 kfree(*alloc_copy);
 363                 *alloc_copy = NULL;
 364         }
 365
 366         if (alloc_bh)
 367                 brelse(alloc_bh);
 368
 369         if (inode) {
 370                 mutex_unlock(&inode->i_mutex);
 371                 iput(inode);
 372         }
 373
 374         mlog_exit(status);
 375         return status;
 376 }
 377
 378 /*
 379  * Step 2: By now, we've completed the journal recovery, we've stamped
 380  * a clean local alloc on disk and dropped the node out of the
 381  * recovery map. Dlm locks will no longer stall, so lets clear out the
 382  * main bitmap.
 383  */
 384 int ocfs2_complete_local_alloc_recovery(struct ocfs2_super *osb,
 385                                         struct ocfs2_dinode *alloc)
 386 {
 387         int status;
 388         struct ocfs2_journal_handle *handle = NULL;
 389         struct buffer_head *main_bm_bh = NULL;
 390         struct inode *main_bm_inode = NULL;
 391
 392         mlog_entry_void();
 393
 394         handle = ocfs2_alloc_handle(osb);
 395         if (!handle) {
 396                 status = -ENOMEM;
 397                 mlog_errno(status);
 398                 goto bail;
 399         }
 400
 401         main_bm_inode = ocfs2_get_system_file_inode(osb,
 402                                                     GLOBAL_BITMAP_SYSTEM_INODE,
 403                                                     OCFS2_INVALID_SLOT);
 404         if (!main_bm_inode) {
 405                 status = -EINVAL;
 406                 mlog_errno(status);
 407                 goto bail;
 408         }
 409
 410         ocfs2_handle_add_inode(handle, main_bm_inode);
 411         status = ocfs2_meta_lock(main_bm_inode, handle, &main_bm_bh, 1);
 412         if (status < 0) {
 413                 mlog_errno(status);
 414                 goto bail;
 415         }
 416
 417         handle = ocfs2_start_trans(osb, handle, OCFS2_WINDOW_MOVE_CREDITS);
 418         if (IS_ERR(handle)) {
 419                 status = PTR_ERR(handle);
 420                 handle = NULL;
 421                 mlog_errno(status);
 422                 goto bail;
 423         }
 424
 425         /* we want the bitmap change to be recorded on disk asap */
 426         ocfs2_handle_set_sync(handle, 1);
 427
 428         status = ocfs2_sync_local_to_main(osb, handle, alloc,
 429                                           main_bm_inode, main_bm_bh);
 430         if (status < 0)
 431                 mlog_errno(status);
 432
 433 bail:
 434         if (handle)
 435                 ocfs2_commit_trans(handle);
 436
 437         if (main_bm_bh)
 438                 brelse(main_bm_bh);
 439
 440         if (main_bm_inode)
 441                 iput(main_bm_inode);
 442
 443         mlog_exit(status);
 444         return status;
 445 }
 446
 447 /*
 448  * make sure we've got at least bitswanted contiguous bits in the
 449  * local alloc. You lose them when you drop i_mutex.
 450  *
 451  * We will add ourselves to the transaction passed in, but may start
 452  * our own in order to shift windows.
 453  */
 454 int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
 455                                    struct ocfs2_journal_handle *passed_handle,
 456                                    u32 bits_wanted,
 457                                    struct ocfs2_alloc_context *ac)
 458 {
 459         int status;
 460         struct ocfs2_dinode *alloc;
 461         struct inode *local_alloc_inode;
 462         unsigned int free_bits;
 463
 464         mlog_entry_void();
 465
 466         BUG_ON(!passed_handle);
 467         BUG_ON(!ac);
 468         BUG_ON(passed_handle->flags & OCFS2_HANDLE_STARTED);
 469
 470         local_alloc_inode =
 471                 ocfs2_get_system_file_inode(osb,
 472                                             LOCAL_ALLOC_SYSTEM_INODE,
 473                                             osb->slot_num);
 474         if (!local_alloc_inode) {
 475                 status = -ENOENT;
 476                 mlog_errno(status);
 477                 goto bail;
 478         }
 479         ocfs2_handle_add_inode(passed_handle, local_alloc_inode);
 480
 481         if (osb->local_alloc_state != OCFS2_LA_ENABLED) {
 482                 status = -ENOSPC;
 483                 goto bail;
 484         }
 485
 486         if (bits_wanted > ocfs2_local_alloc_window_bits(osb)) {
 487                 mlog(0, "Asking for more than my max window size!\n");
 488                 status = -ENOSPC;
 489                 goto bail;
 490         }
 491
 492         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 493
 494         if (le32_to_cpu(alloc->id1.bitmap1.i_used) !=
 495             ocfs2_local_alloc_count_bits(alloc)) {
 496                 ocfs2_error(osb->sb, "local alloc inode %llu says it has "
 497                             "%u free bits, but a count shows %u",
 498                             (unsigned long long)le64_to_cpu(alloc->i_blkno),
 499                             le32_to_cpu(alloc->id1.bitmap1.i_used),
 500                             ocfs2_local_alloc_count_bits(alloc));
 501                 status = -EIO;
 502                 goto bail;
 503         }
 504
 505         free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
 506                 le32_to_cpu(alloc->id1.bitmap1.i_used);
 507         if (bits_wanted > free_bits) {
 508                 /* uhoh, window change time. */
 509                 status =
 510                         ocfs2_local_alloc_slide_window(osb, local_alloc_inode);
 511                 if (status < 0) {
 512                         if (status != -ENOSPC)
 513                                 mlog_errno(status);
 514                         goto bail;
 515                 }
 516         }
 517
 518         ac->ac_inode = igrab(local_alloc_inode);
 519         get_bh(osb->local_alloc_bh);
 520         ac->ac_bh = osb->local_alloc_bh;
 521         ac->ac_which = OCFS2_AC_USE_LOCAL;
 522         status = 0;
 523 bail:
 524         if (local_alloc_inode)
 525                 iput(local_alloc_inode);
 526
 527         mlog_exit(status);
 528         return status;
 529 }
 530
 531 int ocfs2_claim_local_alloc_bits(struct ocfs2_super *osb,
 532                                  struct ocfs2_journal_handle *handle,
 533                                  struct ocfs2_alloc_context *ac,
 534                                  u32 min_bits,
 535                                  u32 *bit_off,
 536                                  u32 *num_bits)
 537 {
 538         int status, start;
 539         struct inode *local_alloc_inode;
 540         u32 bits_wanted;
 541         void *bitmap;
 542         struct ocfs2_dinode *alloc;
 543         struct ocfs2_local_alloc *la;
 544
 545         mlog_entry_void();
 546         BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL);
 547
 548         bits_wanted = ac->ac_bits_wanted - ac->ac_bits_given;
 549         local_alloc_inode = ac->ac_inode;
 550         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 551         la = OCFS2_LOCAL_ALLOC(alloc);
 552
 553         start = ocfs2_local_alloc_find_clear_bits(osb, alloc, bits_wanted);
 554         if (start == -1) {
 555                 /* TODO: Shouldn't we just BUG here? */
 556                 status = -ENOSPC;
 557                 mlog_errno(status);
 558                 goto bail;
 559         }
 560
 561         bitmap = la->la_bitmap;
 562         *bit_off = le32_to_cpu(la->la_bm_off) + start;
 563         /* local alloc is always contiguous by nature -- we never
 564          * delete bits from it! */
 565         *num_bits = bits_wanted;
 566
 567         status = ocfs2_journal_access(handle, local_alloc_inode,
 568                                       osb->local_alloc_bh,
 569                                       OCFS2_JOURNAL_ACCESS_WRITE);
 570         if (status < 0) {
 571                 mlog_errno(status);
 572                 goto bail;
 573         }
 574
 575         while(bits_wanted--)
 576                 ocfs2_set_bit(start++, bitmap);
 577
 578         alloc->id1.bitmap1.i_used = cpu_to_le32(*num_bits +
 579                                 le32_to_cpu(alloc->id1.bitmap1.i_used));
 580
 581         status = ocfs2_journal_dirty(handle, osb->local_alloc_bh);
 582         if (status < 0) {
 583                 mlog_errno(status);
 584                 goto bail;
 585         }
 586
 587         status = 0;
 588 bail:
 589         mlog_exit(status);
 590         return status;
 591 }
 592
 593 static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc)
 594 {
 595         int i;
 596         u8 *buffer;
 597         u32 count = 0;
 598         struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
 599
 600         mlog_entry_void();
 601
 602         buffer = la->la_bitmap;
 603         for (i = 0; i < le16_to_cpu(la->la_size); i++)
 604                 count += hweight8(buffer[i]);
 605
 606         mlog_exit(count);
 607         return count;
 608 }
 609
 610 static int ocfs2_local_alloc_find_clear_bits(struct ocfs2_super *osb,
 611                                              struct ocfs2_dinode *alloc,
 612                                              u32 numbits)
 613 {
 614         int numfound, bitoff, left, startoff, lastzero;
 615         void *bitmap = NULL;
 616
 617         mlog_entry("(numbits wanted = %u)\n", numbits);
 618
 619         if (!alloc->id1.bitmap1.i_total) {
 620                 mlog(0, "No bits in my window!\n");
 621                 bitoff = -1;
 622                 goto bail;
 623         }
 624
 625         bitmap = OCFS2_LOCAL_ALLOC(alloc)->la_bitmap;
 626
 627         numfound = bitoff = startoff = 0;
 628         lastzero = -1;
 629         left = le32_to_cpu(alloc->id1.bitmap1.i_total);
 630         while ((bitoff = ocfs2_find_next_zero_bit(bitmap, left, startoff)) != -1) {
 631                 if (bitoff == left) {
 632                         /* mlog(0, "bitoff (%d) == left", bitoff); */
 633                         break;
 634                 }
 635                 /* mlog(0, "Found a zero: bitoff = %d, startoff = %d, "
 636                    "numfound = %d\n", bitoff, startoff, numfound);*/
 637
 638                 /* Ok, we found a zero bit... is it contig. or do we
 639                  * start over?*/
 640                 if (bitoff == startoff) {
 641                         /* we found a zero */
 642                         numfound++;
 643                         startoff++;
 644                 } else {
 645                         /* got a zero after some ones */
 646                         numfound = 1;
 647                         startoff = bitoff+1;
 648                 }
 649                 /* we got everything we needed */
 650                 if (numfound == numbits) {
 651                         /* mlog(0, "Found it all!\n"); */
 652                         break;
 653                 }
 654         }
 655
 656         mlog(0, "Exiting loop, bitoff = %d, numfound = %d\n", bitoff,
 657              numfound);
 658
 659         if (numfound == numbits)
 660                 bitoff = startoff - numfound;
 661         else
 662                 bitoff = -1;
 663
 664 bail:
 665         mlog_exit(bitoff);
 666         return bitoff;
 667 }
 668
 669 static void ocfs2_clear_local_alloc(struct ocfs2_dinode *alloc)
 670 {
 671         struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
 672         int i;
 673         mlog_entry_void();
 674
 675         alloc->id1.bitmap1.i_total = 0;
 676         alloc->id1.bitmap1.i_used = 0;
 677         la->la_bm_off = 0;
 678         for(i = 0; i < le16_to_cpu(la->la_size); i++)
 679                 la->la_bitmap[i] = 0;
 680
 681         mlog_exit_void();
 682 }
 683
 684 #if 0
 685 /* turn this on and uncomment below to aid debugging window shifts. */
 686 static void ocfs2_verify_zero_bits(unsigned long *bitmap,
 687                                    unsigned int start,
 688                                    unsigned int count)
 689 {
 690         unsigned int tmp = count;
 691         while(tmp--) {
 692                 if (ocfs2_test_bit(start + tmp, bitmap)) {
 693                         printk("ocfs2_verify_zero_bits: start = %u, count = "
 694                                "%u\n", start, count);
 695                         printk("ocfs2_verify_zero_bits: bit %u is set!",
 696                                start + tmp);
 697                         BUG();
 698                 }
 699         }
 700 }
 701 #endif
 702
 703 /*
 704  * sync the local alloc to main bitmap.
 705  *
 706  * assumes you've already locked the main bitmap -- the bitmap inode
 707  * passed is used for caching.
 708  */
 709 static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
 710                                     struct ocfs2_journal_handle *handle,
 711                                     struct ocfs2_dinode *alloc,
 712                                     struct inode *main_bm_inode,
 713                                     struct buffer_head *main_bm_bh)
 714 {
 715         int status = 0;
 716         int bit_off, left, count, start;
 717         u64 la_start_blk;
 718         u64 blkno;
 719         void *bitmap;
 720         struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
 721
 722         mlog_entry("total = %u, COUNT = %u, used = %u\n",
 723                    le32_to_cpu(alloc->id1.bitmap1.i_total),
 724                    ocfs2_local_alloc_count_bits(alloc),
 725                    le32_to_cpu(alloc->id1.bitmap1.i_used));
 726
 727         if (!alloc->id1.bitmap1.i_total) {
 728                 mlog(0, "nothing to sync!\n");
 729                 goto bail;
 730         }
 731
 732         if (le32_to_cpu(alloc->id1.bitmap1.i_used) ==
 733             le32_to_cpu(alloc->id1.bitmap1.i_total)) {
 734                 mlog(0, "all bits were taken!\n");
 735                 goto bail;
 736         }
 737
 738         la_start_blk = ocfs2_clusters_to_blocks(osb->sb,
 739                                                 le32_to_cpu(la->la_bm_off));
 740         bitmap = la->la_bitmap;
 741         start = count = bit_off = 0;
 742         left = le32_to_cpu(alloc->id1.bitmap1.i_total);
 743
 744         while ((bit_off = ocfs2_find_next_zero_bit(bitmap, left, start))
 745                != -1) {
 746                 if ((bit_off < left) && (bit_off == start)) {
 747                         count++;
 748                         start++;
 749                         continue;
 750                 }
 751                 if (count) {
 752                         blkno = la_start_blk +
 753                                 ocfs2_clusters_to_blocks(osb->sb,
 754                                                          start - count);
 755
 756                         mlog(0, "freeing %u bits starting at local alloc bit "
 757                              "%u (la_start_blk = %llu, blkno = %llu)\n",
 758                              count, start - count,
 759                              (unsigned long long)la_start_blk,
 760                              (unsigned long long)blkno);
 761
 762                         status = ocfs2_free_clusters(handle, main_bm_inode,
 763                                                      main_bm_bh, blkno, count);
 764                         if (status < 0) {
 765                                 mlog_errno(status);
 766                                 goto bail;
 767                         }
 768                 }
 769                 if (bit_off >= left)
 770                         break;
 771                 count = 1;
 772                 start = bit_off + 1;
 773         }
 774
 775 bail:
 776         mlog_exit(status);
 777         return status;
 778 }
 779
 780 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
 781                                                 struct ocfs2_journal_handle *handle,
 782                                                 struct ocfs2_alloc_context **ac,
 783                                                 struct inode **bitmap_inode,
 784                                                 struct buffer_head **bitmap_bh)
 785 {
 786         int status;
 787
 788         *ac = kcalloc(1, sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
 789         if (!(*ac)) {
 790                 status = -ENOMEM;
 791                 mlog_errno(status);
 792                 goto bail;
 793         }
 794
 795         (*ac)->ac_handle = handle;
 796         (*ac)->ac_bits_wanted = ocfs2_local_alloc_window_bits(osb);
 797
 798         status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
 799         if (status < 0) {
 800                 if (status != -ENOSPC)
 801                         mlog_errno(status);
 802                 goto bail;
 803         }
 804
 805         *bitmap_inode = (*ac)->ac_inode;
 806         igrab(*bitmap_inode);
 807         *bitmap_bh = (*ac)->ac_bh;
 808         get_bh(*bitmap_bh);
 809         status = 0;
 810 bail:
 811         if ((status < 0) && *ac) {
 812                 ocfs2_free_alloc_context(*ac);
 813                 *ac = NULL;
 814         }
 815
 816         mlog_exit(status);
 817         return status;
 818 }
 819
 820 /*
 821  * pass it the bitmap lock in lock_bh if you have it.
 822  */
 823 static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
 824                                         struct ocfs2_journal_handle *handle,
 825                                         struct ocfs2_alloc_context *ac)
 826 {
 827         int status = 0;
 828         u32 cluster_off, cluster_count;
 829         struct ocfs2_dinode *alloc = NULL;
 830         struct ocfs2_local_alloc *la;
 831
 832         mlog_entry_void();
 833
 834         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 835         la = OCFS2_LOCAL_ALLOC(alloc);
 836
 837         if (alloc->id1.bitmap1.i_total)
 838                 mlog(0, "asking me to alloc a new window over a non-empty "
 839                      "one\n");
 840
 841         mlog(0, "Allocating %u clusters for a new window.\n",
 842              ocfs2_local_alloc_window_bits(osb));
 843
 844         /* Instruct the allocation code to try the most recently used
 845          * cluster group. We'll re-record the group used this pass
 846          * below. */
 847         ac->ac_last_group = osb->la_last_gd;
 848
 849         /* we used the generic suballoc reserve function, but we set
 850          * everything up nicely, so there's no reason why we can't use
 851          * the more specific cluster api to claim bits. */
 852         status = ocfs2_claim_clusters(osb, handle, ac,
 853                                       ocfs2_local_alloc_window_bits(osb),
 854                                       &cluster_off, &cluster_count);
 855         if (status < 0) {
 856                 if (status != -ENOSPC)
 857                         mlog_errno(status);
 858                 goto bail;
 859         }
 860
 861         osb->la_last_gd = ac->ac_last_group;
 862
 863         la->la_bm_off = cpu_to_le32(cluster_off);
 864         alloc->id1.bitmap1.i_total = cpu_to_le32(cluster_count);
 865         /* just in case... In the future when we find space ourselves,
 866          * we don't have to get all contiguous -- but we'll have to
 867          * set all previously used bits in bitmap and update
 868          * la_bits_set before setting the bits in the main bitmap. */
 869         alloc->id1.bitmap1.i_used = 0;
 870         memset(OCFS2_LOCAL_ALLOC(alloc)->la_bitmap, 0,
 871                le16_to_cpu(la->la_size));
 872
 873         mlog(0, "New window allocated:\n");
 874         mlog(0, "window la_bm_off = %u\n",
 875              OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
 876         mlog(0, "window bits = %u\n", le32_to_cpu(alloc->id1.bitmap1.i_total));
 877
 878 bail:
 879         mlog_exit(status);
 880         return status;
 881 }
 882
 883 /* Note that we do *NOT* lock the local alloc inode here as
 884  * it's been locked already for us. */
 885 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
 886                                           struct inode *local_alloc_inode)
 887 {
 888         int status = 0;
 889         struct buffer_head *main_bm_bh = NULL;
 890         struct inode *main_bm_inode = NULL;
 891         struct ocfs2_journal_handle *handle = NULL;
 892         struct ocfs2_dinode *alloc;
 893         struct ocfs2_dinode *alloc_copy = NULL;
 894         struct ocfs2_alloc_context *ac = NULL;
 895
 896         mlog_entry_void();
 897
 898         handle = ocfs2_alloc_handle(osb);
 899         if (!handle) {
 900                 status = -ENOMEM;
 901                 mlog_errno(status);
 902                 goto bail;
 903         }
 904
 905         /* This will lock the main bitmap for us. */
 906         status = ocfs2_local_alloc_reserve_for_window(osb,
 907                                                       handle,
 908                                                       &ac,
 909                                                       &main_bm_inode,
 910                                                       &main_bm_bh);
 911         if (status < 0) {
 912                 if (status != -ENOSPC)
 913                         mlog_errno(status);
 914                 goto bail;
 915         }
 916
 917         handle = ocfs2_start_trans(osb, handle, OCFS2_WINDOW_MOVE_CREDITS);
 918         if (IS_ERR(handle)) {
 919                 status = PTR_ERR(handle);
 920                 handle = NULL;
 921                 mlog_errno(status);
 922                 goto bail;
 923         }
 924
 925         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 926
 927         /* We want to clear the local alloc before doing anything
 928          * else, so that if we error later during this operation,
 929          * local alloc shutdown won't try to double free main bitmap
 930          * bits. Make a copy so the sync function knows which bits to
 931          * free. */
 932         alloc_copy = kmalloc(osb->local_alloc_bh->b_size, GFP_KERNEL);
 933         if (!alloc_copy) {
 934                 status = -ENOMEM;
 935                 mlog_errno(status);
 936                 goto bail;
 937         }
 938         memcpy(alloc_copy, alloc, osb->local_alloc_bh->b_size);
 939
 940         status = ocfs2_journal_access(handle, local_alloc_inode,
 941                                       osb->local_alloc_bh,
 942                                       OCFS2_JOURNAL_ACCESS_WRITE);
 943         if (status < 0) {
 944                 mlog_errno(status);
 945                 goto bail;
 946         }
 947
 948         ocfs2_clear_local_alloc(alloc);
 949
 950         status = ocfs2_journal_dirty(handle, osb->local_alloc_bh);
 951         if (status < 0) {
 952                 mlog_errno(status);
 953                 goto bail;
 954         }
 955
 956         status = ocfs2_sync_local_to_main(osb, handle, alloc_copy,
 957                                           main_bm_inode, main_bm_bh);
 958         if (status < 0) {
 959                 mlog_errno(status);
 960                 goto bail;
 961         }
 962
 963         status = ocfs2_local_alloc_new_window(osb, handle, ac);
 964         if (status < 0) {
 965                 if (status != -ENOSPC)
 966                         mlog_errno(status);
 967                 goto bail;
 968         }
 969
 970         atomic_inc(&osb->alloc_stats.moves);
 971
 972         status = 0;
 973 bail:
 974         if (handle)
 975                 ocfs2_commit_trans(handle);
 976
 977         if (main_bm_bh)
 978                 brelse(main_bm_bh);
 979
 980         if (main_bm_inode)
 981                 iput(main_bm_inode);
 982
 983         if (alloc_copy)
 984                 kfree(alloc_copy);
 985
 986         if (ac)
 987                 ocfs2_free_alloc_context(ac);
 988
 989         mlog_exit(status);
 990         return status;
 991 }
 992