fs/ocfs2/suballoc.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * suballoc.c
   5  *
   6  * metadata alloc and free
   7  * Inspired by ext3 block groups.
   8  *
   9  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2 of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public
  22  * License along with this program; if not, write to the
  23  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24  * Boston, MA 021110-1307, USA.
  25  */
  26
  27 #include <linux/fs.h>
  28 #include <linux/types.h>
  29 #include <linux/slab.h>
  30 #include <linux/highmem.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 #include "uptodate.h"
  46
  47 #include "buffer_head_io.h"
  48
  49 static inline void ocfs2_debug_bg(struct ocfs2_group_desc *bg);
  50 static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe);
  51 static inline u16 ocfs2_find_victim_chain(struct ocfs2_chain_list *cl);
  52 static int ocfs2_block_group_fill(handle_t *handle,
  53                                   struct inode *alloc_inode,
  54                                   struct buffer_head *bg_bh,
  55                                   u64 group_blkno,
  56                                   u16 my_chain,
  57                                   struct ocfs2_chain_list *cl);
  58 static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
  59                                    struct inode *alloc_inode,
  60                                    struct buffer_head *bh);
  61
  62 static int ocfs2_cluster_group_search(struct inode *inode,
  63                                       struct buffer_head *group_bh,
  64                                       u32 bits_wanted, u32 min_bits,
  65                                       u16 *bit_off, u16 *bits_found);
  66 static int ocfs2_block_group_search(struct inode *inode,
  67                                     struct buffer_head *group_bh,
  68                                     u32 bits_wanted, u32 min_bits,
  69                                     u16 *bit_off, u16 *bits_found);
  70 static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
  71                                      struct ocfs2_alloc_context *ac,
  72                                      handle_t *handle,
  73                                      u32 bits_wanted,
  74                                      u32 min_bits,
  75                                      u16 *bit_off,
  76                                      unsigned int *num_bits,
  77                                      u64 *bg_blkno);
  78 static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
  79                                          int nr);
  80 static inline int ocfs2_block_group_set_bits(handle_t *handle,
  81                                              struct inode *alloc_inode,
  82                                              struct ocfs2_group_desc *bg,
  83                                              struct buffer_head *group_bh,
  84                                              unsigned int bit_off,
  85                                              unsigned int num_bits);
  86 static inline int ocfs2_block_group_clear_bits(handle_t *handle,
  87                                                struct inode *alloc_inode,
  88                                                struct ocfs2_group_desc *bg,
  89                                                struct buffer_head *group_bh,
  90                                                unsigned int bit_off,
  91                                                unsigned int num_bits);
  92
  93 static int ocfs2_relink_block_group(handle_t *handle,
  94                                     struct inode *alloc_inode,
  95                                     struct buffer_head *fe_bh,
  96                                     struct buffer_head *bg_bh,
  97                                     struct buffer_head *prev_bg_bh,
  98                                     u16 chain);
  99 static inline int ocfs2_block_group_reasonably_empty(struct ocfs2_group_desc *bg,
 100                                                      u32 wanted);
 101 static int ocfs2_free_suballoc_bits(handle_t *handle,
 102                                     struct inode *alloc_inode,
 103                                     struct buffer_head *alloc_bh,
 104                                     unsigned int start_bit,
 105                                     u64 bg_blkno,
 106                                     unsigned int count);
 107 static inline u64 ocfs2_which_suballoc_group(u64 block,
 108                                              unsigned int bit);
 109 static inline u32 ocfs2_desc_bitmap_to_cluster_off(struct inode *inode,
 110                                                    u64 bg_blkno,
 111                                                    u16 bg_bit_off);
 112 static inline u64 ocfs2_which_cluster_group(struct inode *inode,
 113                                             u32 cluster);
 114 static inline void ocfs2_block_to_cluster_group(struct inode *inode,
 115                                                 u64 data_blkno,
 116                                                 u64 *bg_blkno,
 117                                                 u16 *bg_bit_off);
 118
 119 void ocfs2_free_alloc_context(struct ocfs2_alloc_context *ac)
 120 {
 121         struct inode *inode = ac->ac_inode;
 122
 123         if (inode) {
 124                 if (ac->ac_which != OCFS2_AC_USE_LOCAL)
 125                         ocfs2_meta_unlock(inode, 1);
 126
 127                 mutex_unlock(&inode->i_mutex);
 128
 129                 iput(inode);
 130         }
 131         if (ac->ac_bh)
 132                 brelse(ac->ac_bh);
 133         kfree(ac);
 134 }
 135
 136 static u32 ocfs2_bits_per_group(struct ocfs2_chain_list *cl)
 137 {
 138         return (u32)le16_to_cpu(cl->cl_cpg) * (u32)le16_to_cpu(cl->cl_bpc);
 139 }
 140
 141 /* somewhat more expensive than our other checks, so use sparingly. */
 142 static int ocfs2_check_group_descriptor(struct super_block *sb,
 143                                         struct ocfs2_dinode *di,
 144                                         struct ocfs2_group_desc *gd)
 145 {
 146         unsigned int max_bits;
 147
 148         if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
 149                 OCFS2_RO_ON_INVALID_GROUP_DESC(sb, gd);
 150                 return -EIO;
 151         }
 152
 153         if (di->i_blkno != gd->bg_parent_dinode) {
 154                 ocfs2_error(sb, "Group descriptor # %llu has bad parent "
 155                             "pointer (%llu, expected %llu)",
 156                             (unsigned long long)le64_to_cpu(gd->bg_blkno),
 157                             (unsigned long long)le64_to_cpu(gd->bg_parent_dinode),
 158                             (unsigned long long)le64_to_cpu(di->i_blkno));
 159                 return -EIO;
 160         }
 161
 162         max_bits = le16_to_cpu(di->id2.i_chain.cl_cpg) * le16_to_cpu(di->id2.i_chain.cl_bpc);
 163         if (le16_to_cpu(gd->bg_bits) > max_bits) {
 164                 ocfs2_error(sb, "Group descriptor # %llu has bit count of %u",
 165                             (unsigned long long)le64_to_cpu(gd->bg_blkno),
 166                             le16_to_cpu(gd->bg_bits));
 167                 return -EIO;
 168         }
 169
 170         if (le16_to_cpu(gd->bg_chain) >=
 171             le16_to_cpu(di->id2.i_chain.cl_next_free_rec)) {
 172                 ocfs2_error(sb, "Group descriptor # %llu has bad chain %u",
 173                             (unsigned long long)le64_to_cpu(gd->bg_blkno),
 174                             le16_to_cpu(gd->bg_chain));
 175                 return -EIO;
 176         }
 177
 178         if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {
 179                 ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
 180                             "claims that %u are free",
 181                             (unsigned long long)le64_to_cpu(gd->bg_blkno),
 182                             le16_to_cpu(gd->bg_bits),
 183                             le16_to_cpu(gd->bg_free_bits_count));
 184                 return -EIO;
 185         }
 186
 187         if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {
 188                 ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "
 189                             "max bitmap bits of %u",
 190                             (unsigned long long)le64_to_cpu(gd->bg_blkno),
 191                             le16_to_cpu(gd->bg_bits),
 192                             8 * le16_to_cpu(gd->bg_size));
 193                 return -EIO;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static int ocfs2_block_group_fill(handle_t *handle,
 200                                   struct inode *alloc_inode,
 201                                   struct buffer_head *bg_bh,
 202                                   u64 group_blkno,
 203                                   u16 my_chain,
 204                                   struct ocfs2_chain_list *cl)
 205 {
 206         int status = 0;
 207         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 208         struct super_block * sb = alloc_inode->i_sb;
 209
 210         mlog_entry_void();
 211
 212         if (((unsigned long long) bg_bh->b_blocknr) != group_blkno) {
 213                 ocfs2_error(alloc_inode->i_sb, "group block (%llu) != "
 214                             "b_blocknr (%llu)",
 215                             (unsigned long long)group_blkno,
 216                             (unsigned long long) bg_bh->b_blocknr);
 217                 status = -EIO;
 218                 goto bail;
 219         }
 220
 221         status = ocfs2_journal_access(handle,
 222                                       alloc_inode,
 223                                       bg_bh,
 224                                       OCFS2_JOURNAL_ACCESS_CREATE);
 225         if (status < 0) {
 226                 mlog_errno(status);
 227                 goto bail;
 228         }
 229
 230         memset(bg, 0, sb->s_blocksize);
 231         strcpy(bg->bg_signature, OCFS2_GROUP_DESC_SIGNATURE);
 232         bg->bg_generation = cpu_to_le32(OCFS2_SB(sb)->fs_generation);
 233         bg->bg_size = cpu_to_le16(ocfs2_group_bitmap_size(sb));
 234         bg->bg_bits = cpu_to_le16(ocfs2_bits_per_group(cl));
 235         bg->bg_chain = cpu_to_le16(my_chain);
 236         bg->bg_next_group = cl->cl_recs[my_chain].c_blkno;
 237         bg->bg_parent_dinode = cpu_to_le64(OCFS2_I(alloc_inode)->ip_blkno);
 238         bg->bg_blkno = cpu_to_le64(group_blkno);
 239         /* set the 1st bit in the bitmap to account for the descriptor block */
 240         ocfs2_set_bit(0, (unsigned long *)bg->bg_bitmap);
 241         bg->bg_free_bits_count = cpu_to_le16(le16_to_cpu(bg->bg_bits) - 1);
 242
 243         status = ocfs2_journal_dirty(handle, bg_bh);
 244         if (status < 0)
 245                 mlog_errno(status);
 246
 247         /* There is no need to zero out or otherwise initialize the
 248          * other blocks in a group - All valid FS metadata in a block
 249          * group stores the superblock fs_generation value at
 250          * allocation time. */
 251
 252 bail:
 253         mlog_exit(status);
 254         return status;
 255 }
 256
 257 static inline u16 ocfs2_find_smallest_chain(struct ocfs2_chain_list *cl)
 258 {
 259         u16 curr, best;
 260
 261         best = curr = 0;
 262         while (curr < le16_to_cpu(cl->cl_count)) {
 263                 if (le32_to_cpu(cl->cl_recs[best].c_total) >
 264                     le32_to_cpu(cl->cl_recs[curr].c_total))
 265                         best = curr;
 266                 curr++;
 267         }
 268         return best;
 269 }
 270
 271 /*
 272  * We expect the block group allocator to already be locked.
 273  */
 274 static int ocfs2_block_group_alloc(struct ocfs2_super *osb,
 275                                    struct inode *alloc_inode,
 276                                    struct buffer_head *bh)
 277 {
 278         int status, credits;
 279         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) bh->b_data;
 280         struct ocfs2_chain_list *cl;
 281         struct ocfs2_alloc_context *ac = NULL;
 282         handle_t *handle = NULL;
 283         u32 bit_off, num_bits;
 284         u16 alloc_rec;
 285         u64 bg_blkno;
 286         struct buffer_head *bg_bh = NULL;
 287         struct ocfs2_group_desc *bg;
 288
 289         BUG_ON(ocfs2_is_cluster_bitmap(alloc_inode));
 290
 291         mlog_entry_void();
 292
 293         cl = &fe->id2.i_chain;
 294         status = ocfs2_reserve_clusters(osb,
 295                                         le16_to_cpu(cl->cl_cpg),
 296                                         &ac);
 297         if (status < 0) {
 298                 if (status != -ENOSPC)
 299                         mlog_errno(status);
 300                 goto bail;
 301         }
 302
 303         credits = ocfs2_calc_group_alloc_credits(osb->sb,
 304                                                  le16_to_cpu(cl->cl_cpg));
 305         handle = ocfs2_start_trans(osb, credits);
 306         if (IS_ERR(handle)) {
 307                 status = PTR_ERR(handle);
 308                 handle = NULL;
 309                 mlog_errno(status);
 310                 goto bail;
 311         }
 312
 313         status = ocfs2_claim_clusters(osb,
 314                                       handle,
 315                                       ac,
 316                                       le16_to_cpu(cl->cl_cpg),
 317                                       &bit_off,
 318                                       &num_bits);
 319         if (status < 0) {
 320                 if (status != -ENOSPC)
 321                         mlog_errno(status);
 322                 goto bail;
 323         }
 324
 325         alloc_rec = ocfs2_find_smallest_chain(cl);
 326
 327         /* setup the group */
 328         bg_blkno = ocfs2_clusters_to_blocks(osb->sb, bit_off);
 329         mlog(0, "new descriptor, record %u, at block %llu\n",
 330              alloc_rec, (unsigned long long)bg_blkno);
 331
 332         bg_bh = sb_getblk(osb->sb, bg_blkno);
 333         if (!bg_bh) {
 334                 status = -EIO;
 335                 mlog_errno(status);
 336                 goto bail;
 337         }
 338         ocfs2_set_new_buffer_uptodate(alloc_inode, bg_bh);
 339
 340         status = ocfs2_block_group_fill(handle,
 341                                         alloc_inode,
 342                                         bg_bh,
 343                                         bg_blkno,
 344                                         alloc_rec,
 345                                         cl);
 346         if (status < 0) {
 347                 mlog_errno(status);
 348                 goto bail;
 349         }
 350
 351         bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 352
 353         status = ocfs2_journal_access(handle, alloc_inode,
 354                                       bh, OCFS2_JOURNAL_ACCESS_WRITE);
 355         if (status < 0) {
 356                 mlog_errno(status);
 357                 goto bail;
 358         }
 359
 360         le32_add_cpu(&cl->cl_recs[alloc_rec].c_free,
 361                      le16_to_cpu(bg->bg_free_bits_count));
 362         le32_add_cpu(&cl->cl_recs[alloc_rec].c_total, le16_to_cpu(bg->bg_bits));
 363         cl->cl_recs[alloc_rec].c_blkno  = cpu_to_le64(bg_blkno);
 364         if (le16_to_cpu(cl->cl_next_free_rec) < le16_to_cpu(cl->cl_count))
 365                 le16_add_cpu(&cl->cl_next_free_rec, 1);
 366
 367         le32_add_cpu(&fe->id1.bitmap1.i_used, le16_to_cpu(bg->bg_bits) -
 368                                         le16_to_cpu(bg->bg_free_bits_count));
 369         le32_add_cpu(&fe->id1.bitmap1.i_total, le16_to_cpu(bg->bg_bits));
 370         le32_add_cpu(&fe->i_clusters, le16_to_cpu(cl->cl_cpg));
 371
 372         status = ocfs2_journal_dirty(handle, bh);
 373         if (status < 0) {
 374                 mlog_errno(status);
 375                 goto bail;
 376         }
 377
 378         spin_lock(&OCFS2_I(alloc_inode)->ip_lock);
 379         OCFS2_I(alloc_inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
 380         fe->i_size = cpu_to_le64(ocfs2_clusters_to_bytes(alloc_inode->i_sb,
 381                                              le32_to_cpu(fe->i_clusters)));
 382         spin_unlock(&OCFS2_I(alloc_inode)->ip_lock);
 383         i_size_write(alloc_inode, le64_to_cpu(fe->i_size));
 384         alloc_inode->i_blocks =
 385                 ocfs2_align_bytes_to_sectors(i_size_read(alloc_inode));
 386
 387         status = 0;
 388 bail:
 389         if (handle)
 390                 ocfs2_commit_trans(osb, handle);
 391
 392         if (ac)
 393                 ocfs2_free_alloc_context(ac);
 394
 395         if (bg_bh)
 396                 brelse(bg_bh);
 397
 398         mlog_exit(status);
 399         return status;
 400 }
 401
 402 static int ocfs2_reserve_suballoc_bits(struct ocfs2_super *osb,
 403                                        struct ocfs2_alloc_context *ac,
 404                                        int type,
 405                                        u32 slot)
 406 {
 407         int status;
 408         u32 bits_wanted = ac->ac_bits_wanted;
 409         struct inode *alloc_inode;
 410         struct buffer_head *bh = NULL;
 411         struct ocfs2_dinode *fe;
 412         u32 free_bits;
 413
 414         mlog_entry_void();
 415
 416         alloc_inode = ocfs2_get_system_file_inode(osb, type, slot);
 417         if (!alloc_inode) {
 418                 mlog_errno(-EINVAL);
 419                 return -EINVAL;
 420         }
 421
 422         mutex_lock(&alloc_inode->i_mutex);
 423
 424         status = ocfs2_meta_lock(alloc_inode, &bh, 1);
 425         if (status < 0) {
 426                 mutex_unlock(&alloc_inode->i_mutex);
 427                 iput(alloc_inode);
 428
 429                 mlog_errno(status);
 430                 return status;
 431         }
 432
 433         ac->ac_inode = alloc_inode;
 434
 435         fe = (struct ocfs2_dinode *) bh->b_data;
 436         if (!OCFS2_IS_VALID_DINODE(fe)) {
 437                 OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
 438                 status = -EIO;
 439                 goto bail;
 440         }
 441         if (!(fe->i_flags & cpu_to_le32(OCFS2_CHAIN_FL))) {
 442                 ocfs2_error(alloc_inode->i_sb, "Invalid chain allocator %llu",
 443                             (unsigned long long)le64_to_cpu(fe->i_blkno));
 444                 status = -EIO;
 445                 goto bail;
 446         }
 447
 448         free_bits = le32_to_cpu(fe->id1.bitmap1.i_total) -
 449                 le32_to_cpu(fe->id1.bitmap1.i_used);
 450
 451         if (bits_wanted > free_bits) {
 452                 /* cluster bitmap never grows */
 453                 if (ocfs2_is_cluster_bitmap(alloc_inode)) {
 454                         mlog(0, "Disk Full: wanted=%u, free_bits=%u\n",
 455                              bits_wanted, free_bits);
 456                         status = -ENOSPC;
 457                         goto bail;
 458                 }
 459
 460                 status = ocfs2_block_group_alloc(osb, alloc_inode, bh);
 461                 if (status < 0) {
 462                         if (status != -ENOSPC)
 463                                 mlog_errno(status);
 464                         goto bail;
 465                 }
 466                 atomic_inc(&osb->alloc_stats.bg_extends);
 467
 468                 /* You should never ask for this much metadata */
 469                 BUG_ON(bits_wanted >
 470                        (le32_to_cpu(fe->id1.bitmap1.i_total)
 471                         - le32_to_cpu(fe->id1.bitmap1.i_used)));
 472         }
 473
 474         get_bh(bh);
 475         ac->ac_bh = bh;
 476 bail:
 477         if (bh)
 478                 brelse(bh);
 479
 480         mlog_exit(status);
 481         return status;
 482 }
 483
 484 int ocfs2_reserve_new_metadata(struct ocfs2_super *osb,
 485                                struct ocfs2_dinode *fe,
 486                                struct ocfs2_alloc_context **ac)
 487 {
 488         int status;
 489         u32 slot;
 490
 491         *ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
 492         if (!(*ac)) {
 493                 status = -ENOMEM;
 494                 mlog_errno(status);
 495                 goto bail;
 496         }
 497
 498         (*ac)->ac_bits_wanted = ocfs2_extend_meta_needed(fe);
 499         (*ac)->ac_which = OCFS2_AC_USE_META;
 500
 501 #ifndef OCFS2_USE_ALL_METADATA_SUBALLOCATORS
 502         slot = 0;
 503 #else
 504         slot = osb->slot_num;
 505 #endif
 506
 507         (*ac)->ac_group_search = ocfs2_block_group_search;
 508
 509         status = ocfs2_reserve_suballoc_bits(osb, (*ac),
 510                                              EXTENT_ALLOC_SYSTEM_INODE, slot);
 511         if (status < 0) {
 512                 if (status != -ENOSPC)
 513                         mlog_errno(status);
 514                 goto bail;
 515         }
 516
 517         status = 0;
 518 bail:
 519         if ((status < 0) && *ac) {
 520                 ocfs2_free_alloc_context(*ac);
 521                 *ac = NULL;
 522         }
 523
 524         mlog_exit(status);
 525         return status;
 526 }
 527
 528 int ocfs2_reserve_new_inode(struct ocfs2_super *osb,
 529                             struct ocfs2_alloc_context **ac)
 530 {
 531         int status;
 532
 533         *ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
 534         if (!(*ac)) {
 535                 status = -ENOMEM;
 536                 mlog_errno(status);
 537                 goto bail;
 538         }
 539
 540         (*ac)->ac_bits_wanted = 1;
 541         (*ac)->ac_which = OCFS2_AC_USE_INODE;
 542
 543         (*ac)->ac_group_search = ocfs2_block_group_search;
 544
 545         status = ocfs2_reserve_suballoc_bits(osb, *ac,
 546                                              INODE_ALLOC_SYSTEM_INODE,
 547                                              osb->slot_num);
 548         if (status < 0) {
 549                 if (status != -ENOSPC)
 550                         mlog_errno(status);
 551                 goto bail;
 552         }
 553
 554         status = 0;
 555 bail:
 556         if ((status < 0) && *ac) {
 557                 ocfs2_free_alloc_context(*ac);
 558                 *ac = NULL;
 559         }
 560
 561         mlog_exit(status);
 562         return status;
 563 }
 564
 565 /* local alloc code has to do the same thing, so rather than do this
 566  * twice.. */
 567 int ocfs2_reserve_cluster_bitmap_bits(struct ocfs2_super *osb,
 568                                       struct ocfs2_alloc_context *ac)
 569 {
 570         int status;
 571
 572         ac->ac_which = OCFS2_AC_USE_MAIN;
 573         ac->ac_group_search = ocfs2_cluster_group_search;
 574
 575         status = ocfs2_reserve_suballoc_bits(osb, ac,
 576                                              GLOBAL_BITMAP_SYSTEM_INODE,
 577                                              OCFS2_INVALID_SLOT);
 578         if (status < 0 && status != -ENOSPC) {
 579                 mlog_errno(status);
 580                 goto bail;
 581         }
 582
 583 bail:
 584         return status;
 585 }
 586
 587 /* Callers don't need to care which bitmap (local alloc or main) to
 588  * use so we figure it out for them, but unfortunately this clutters
 589  * things a bit. */
 590 int ocfs2_reserve_clusters(struct ocfs2_super *osb,
 591                            u32 bits_wanted,
 592                            struct ocfs2_alloc_context **ac)
 593 {
 594         int status;
 595
 596         mlog_entry_void();
 597
 598         *ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
 599         if (!(*ac)) {
 600                 status = -ENOMEM;
 601                 mlog_errno(status);
 602                 goto bail;
 603         }
 604
 605         (*ac)->ac_bits_wanted = bits_wanted;
 606
 607         status = -ENOSPC;
 608         if (ocfs2_alloc_should_use_local(osb, bits_wanted)) {
 609                 status = ocfs2_reserve_local_alloc_bits(osb,
 610                                                         bits_wanted,
 611                                                         *ac);
 612                 if ((status < 0) && (status != -ENOSPC)) {
 613                         mlog_errno(status);
 614                         goto bail;
 615                 } else if (status == -ENOSPC) {
 616                         /* reserve_local_bits will return enospc with
 617                          * the local alloc inode still locked, so we
 618                          * can change this safely here. */
 619                         mlog(0, "Disabling local alloc\n");
 620                         /* We set to OCFS2_LA_DISABLED so that umount
 621                          * can clean up what's left of the local
 622                          * allocation */
 623                         osb->local_alloc_state = OCFS2_LA_DISABLED;
 624                 }
 625         }
 626
 627         if (status == -ENOSPC) {
 628                 status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
 629                 if (status < 0) {
 630                         if (status != -ENOSPC)
 631                                 mlog_errno(status);
 632                         goto bail;
 633                 }
 634         }
 635
 636         status = 0;
 637 bail:
 638         if ((status < 0) && *ac) {
 639                 ocfs2_free_alloc_context(*ac);
 640                 *ac = NULL;
 641         }
 642
 643         mlog_exit(status);
 644         return status;
 645 }
 646
 647 /*
 648  * More or less lifted from ext3. I'll leave their description below:
 649  *
 650  * "For ext3 allocations, we must not reuse any blocks which are
 651  * allocated in the bitmap buffer's "last committed data" copy.  This
 652  * prevents deletes from freeing up the page for reuse until we have
 653  * committed the delete transaction.
 654  *
 655  * If we didn't do this, then deleting something and reallocating it as
 656  * data would allow the old block to be overwritten before the
 657  * transaction committed (because we force data to disk before commit).
 658  * This would lead to corruption if we crashed between overwriting the
 659  * data and committing the delete.
 660  *
 661  * @@@ We may want to make this allocation behaviour conditional on
 662  * data-writes at some point, and disable it for metadata allocations or
 663  * sync-data inodes."
 664  *
 665  * Note: OCFS2 already does this differently for metadata vs data
 666  * allocations, as those bitmaps are seperate and undo access is never
 667  * called on a metadata group descriptor.
 668  */
 669 static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,
 670                                          int nr)
 671 {
 672         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 673
 674         if (ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap))
 675                 return 0;
 676         if (!buffer_jbd(bg_bh) || !bh2jh(bg_bh)->b_committed_data)
 677                 return 1;
 678
 679         bg = (struct ocfs2_group_desc *) bh2jh(bg_bh)->b_committed_data;
 680         return !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
 681 }
 682
 683 static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,
 684                                              struct buffer_head *bg_bh,
 685                                              unsigned int bits_wanted,
 686                                              unsigned int total_bits,
 687                                              u16 *bit_off,
 688                                              u16 *bits_found)
 689 {
 690         void *bitmap;
 691         u16 best_offset, best_size;
 692         int offset, start, found, status = 0;
 693         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 694
 695         if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {
 696                 OCFS2_RO_ON_INVALID_GROUP_DESC(osb->sb, bg);
 697                 return -EIO;
 698         }
 699
 700         found = start = best_offset = best_size = 0;
 701         bitmap = bg->bg_bitmap;
 702
 703         while((offset = ocfs2_find_next_zero_bit(bitmap, total_bits, start)) != -1) {
 704                 if (offset == total_bits)
 705                         break;
 706
 707                 if (!ocfs2_test_bg_bit_allocatable(bg_bh, offset)) {
 708                         /* We found a zero, but we can't use it as it
 709                          * hasn't been put to disk yet! */
 710                         found = 0;
 711                         start = offset + 1;
 712                 } else if (offset == start) {
 713                         /* we found a zero */
 714                         found++;
 715                         /* move start to the next bit to test */
 716                         start++;
 717                 } else {
 718                         /* got a zero after some ones */
 719                         found = 1;
 720                         start = offset + 1;
 721                 }
 722                 if (found > best_size) {
 723                         best_size = found;
 724                         best_offset = start - found;
 725                 }
 726                 /* we got everything we needed */
 727                 if (found == bits_wanted) {
 728                         /* mlog(0, "Found it all!\n"); */
 729                         break;
 730                 }
 731         }
 732
 733         /* XXX: I think the first clause is equivalent to the second
 734          *      - jlbec */
 735         if (found == bits_wanted) {
 736                 *bit_off = start - found;
 737                 *bits_found = found;
 738         } else if (best_size) {
 739                 *bit_off = best_offset;
 740                 *bits_found = best_size;
 741         } else {
 742                 status = -ENOSPC;
 743                 /* No error log here -- see the comment above
 744                  * ocfs2_test_bg_bit_allocatable */
 745         }
 746
 747         return status;
 748 }
 749
 750 static inline int ocfs2_block_group_set_bits(handle_t *handle,
 751                                              struct inode *alloc_inode,
 752                                              struct ocfs2_group_desc *bg,
 753                                              struct buffer_head *group_bh,
 754                                              unsigned int bit_off,
 755                                              unsigned int num_bits)
 756 {
 757         int status;
 758         void *bitmap = bg->bg_bitmap;
 759         int journal_type = OCFS2_JOURNAL_ACCESS_WRITE;
 760
 761         mlog_entry_void();
 762
 763         if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {
 764                 OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);
 765                 status = -EIO;
 766                 goto bail;
 767         }
 768         BUG_ON(le16_to_cpu(bg->bg_free_bits_count) < num_bits);
 769
 770         mlog(0, "block_group_set_bits: off = %u, num = %u\n", bit_off,
 771              num_bits);
 772
 773         if (ocfs2_is_cluster_bitmap(alloc_inode))
 774                 journal_type = OCFS2_JOURNAL_ACCESS_UNDO;
 775
 776         status = ocfs2_journal_access(handle,
 777                                       alloc_inode,
 778                                       group_bh,
 779                                       journal_type);
 780         if (status < 0) {
 781                 mlog_errno(status);
 782                 goto bail;
 783         }
 784
 785         le16_add_cpu(&bg->bg_free_bits_count, -num_bits);
 786
 787         while(num_bits--)
 788                 ocfs2_set_bit(bit_off++, bitmap);
 789
 790         status = ocfs2_journal_dirty(handle,
 791                                      group_bh);
 792         if (status < 0) {
 793                 mlog_errno(status);
 794                 goto bail;
 795         }
 796
 797 bail:
 798         mlog_exit(status);
 799         return status;
 800 }
 801
 802 /* find the one with the most empty bits */
 803 static inline u16 ocfs2_find_victim_chain(struct ocfs2_chain_list *cl)
 804 {
 805         u16 curr, best;
 806
 807         BUG_ON(!cl->cl_next_free_rec);
 808
 809         best = curr = 0;
 810         while (curr < le16_to_cpu(cl->cl_next_free_rec)) {
 811                 if (le32_to_cpu(cl->cl_recs[curr].c_free) >
 812                     le32_to_cpu(cl->cl_recs[best].c_free))
 813                         best = curr;
 814                 curr++;
 815         }
 816
 817         BUG_ON(best >= le16_to_cpu(cl->cl_next_free_rec));
 818         return best;
 819 }
 820
 821 static int ocfs2_relink_block_group(handle_t *handle,
 822                                     struct inode *alloc_inode,
 823                                     struct buffer_head *fe_bh,
 824                                     struct buffer_head *bg_bh,
 825                                     struct buffer_head *prev_bg_bh,
 826                                     u16 chain)
 827 {
 828         int status;
 829         /* there is a really tiny chance the journal calls could fail,
 830          * but we wouldn't want inconsistent blocks in *any* case. */
 831         u64 fe_ptr, bg_ptr, prev_bg_ptr;
 832         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) fe_bh->b_data;
 833         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
 834         struct ocfs2_group_desc *prev_bg = (struct ocfs2_group_desc *) prev_bg_bh->b_data;
 835
 836         if (!OCFS2_IS_VALID_DINODE(fe)) {
 837                 OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
 838                 status = -EIO;
 839                 goto out;
 840         }
 841         if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {
 842                 OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);
 843                 status = -EIO;
 844                 goto out;
 845         }
 846         if (!OCFS2_IS_VALID_GROUP_DESC(prev_bg)) {
 847                 OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, prev_bg);
 848                 status = -EIO;
 849                 goto out;
 850         }
 851
 852         mlog(0, "Suballoc %llu, chain %u, move group %llu to top, prev = %llu\n",
 853              (unsigned long long)fe->i_blkno, chain,
 854              (unsigned long long)bg->bg_blkno,
 855              (unsigned long long)prev_bg->bg_blkno);
 856
 857         fe_ptr = le64_to_cpu(fe->id2.i_chain.cl_recs[chain].c_blkno);
 858         bg_ptr = le64_to_cpu(bg->bg_next_group);
 859         prev_bg_ptr = le64_to_cpu(prev_bg->bg_next_group);
 860
 861         status = ocfs2_journal_access(handle, alloc_inode, prev_bg_bh,
 862                                       OCFS2_JOURNAL_ACCESS_WRITE);
 863         if (status < 0) {
 864                 mlog_errno(status);
 865                 goto out_rollback;
 866         }
 867
 868         prev_bg->bg_next_group = bg->bg_next_group;
 869
 870         status = ocfs2_journal_dirty(handle, prev_bg_bh);
 871         if (status < 0) {
 872                 mlog_errno(status);
 873                 goto out_rollback;
 874         }
 875
 876         status = ocfs2_journal_access(handle, alloc_inode, bg_bh,
 877                                       OCFS2_JOURNAL_ACCESS_WRITE);
 878         if (status < 0) {
 879                 mlog_errno(status);
 880                 goto out_rollback;
 881         }
 882
 883         bg->bg_next_group = fe->id2.i_chain.cl_recs[chain].c_blkno;
 884
 885         status = ocfs2_journal_dirty(handle, bg_bh);
 886         if (status < 0) {
 887                 mlog_errno(status);
 888                 goto out_rollback;
 889         }
 890
 891         status = ocfs2_journal_access(handle, alloc_inode, fe_bh,
 892                                       OCFS2_JOURNAL_ACCESS_WRITE);
 893         if (status < 0) {
 894                 mlog_errno(status);
 895                 goto out_rollback;
 896         }
 897
 898         fe->id2.i_chain.cl_recs[chain].c_blkno = bg->bg_blkno;
 899
 900         status = ocfs2_journal_dirty(handle, fe_bh);
 901         if (status < 0) {
 902                 mlog_errno(status);
 903                 goto out_rollback;
 904         }
 905
 906         status = 0;
 907 out_rollback:
 908         if (status < 0) {
 909                 fe->id2.i_chain.cl_recs[chain].c_blkno = cpu_to_le64(fe_ptr);
 910                 bg->bg_next_group = cpu_to_le64(bg_ptr);
 911                 prev_bg->bg_next_group = cpu_to_le64(prev_bg_ptr);
 912         }
 913 out:
 914         mlog_exit(status);
 915         return status;
 916 }
 917
 918 static inline int ocfs2_block_group_reasonably_empty(struct ocfs2_group_desc *bg,
 919                                                      u32 wanted)
 920 {
 921         return le16_to_cpu(bg->bg_free_bits_count) > wanted;
 922 }
 923
 924 /* return 0 on success, -ENOSPC to keep searching and any other < 0
 925  * value on error. */
 926 static int ocfs2_cluster_group_search(struct inode *inode,
 927                                       struct buffer_head *group_bh,
 928                                       u32 bits_wanted, u32 min_bits,
 929                                       u16 *bit_off, u16 *bits_found)
 930 {
 931         int search = -ENOSPC;
 932         int ret;
 933         struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *) group_bh->b_data;
 934         u16 tmp_off, tmp_found;
 935         unsigned int max_bits, gd_cluster_off;
 936
 937         BUG_ON(!ocfs2_is_cluster_bitmap(inode));
 938
 939         if (gd->bg_free_bits_count) {
 940                 max_bits = le16_to_cpu(gd->bg_bits);
 941
 942                 /* Tail groups in cluster bitmaps which aren't cpg
 943                  * aligned are prone to partial extention by a failed
 944                  * fs resize. If the file system resize never got to
 945                  * update the dinode cluster count, then we don't want
 946                  * to trust any clusters past it, regardless of what
 947                  * the group descriptor says. */
 948                 gd_cluster_off = ocfs2_blocks_to_clusters(inode->i_sb,
 949                                                           le64_to_cpu(gd->bg_blkno));
 950                 if ((gd_cluster_off + max_bits) >
 951                     OCFS2_I(inode)->ip_clusters) {
 952                         max_bits = OCFS2_I(inode)->ip_clusters - gd_cluster_off;
 953                         mlog(0, "Desc %llu, bg_bits %u, clusters %u, use %u\n",
 954                              (unsigned long long)le64_to_cpu(gd->bg_blkno),
 955                              le16_to_cpu(gd->bg_bits),
 956                              OCFS2_I(inode)->ip_clusters, max_bits);
 957                 }
 958
 959                 ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),
 960                                                         group_bh, bits_wanted,
 961                                                         max_bits,
 962                                                         &tmp_off, &tmp_found);
 963                 if (ret)
 964                         return ret;
 965
 966                 /* ocfs2_block_group_find_clear_bits() might
 967                  * return success, but we still want to return
 968                  * -ENOSPC unless it found the minimum number
 969                  * of bits. */
 970                 if (min_bits <= tmp_found) {
 971                         *bit_off = tmp_off;
 972                         *bits_found = tmp_found;
 973                         search = 0; /* success */
 974                 }
 975         }
 976
 977         return search;
 978 }
 979
 980 static int ocfs2_block_group_search(struct inode *inode,
 981                                     struct buffer_head *group_bh,
 982                                     u32 bits_wanted, u32 min_bits,
 983                                     u16 *bit_off, u16 *bits_found)
 984 {
 985         int ret = -ENOSPC;
 986         struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) group_bh->b_data;
 987
 988         BUG_ON(min_bits != 1);
 989         BUG_ON(ocfs2_is_cluster_bitmap(inode));
 990
 991         if (bg->bg_free_bits_count)
 992                 ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),
 993                                                         group_bh, bits_wanted,
 994                                                         le16_to_cpu(bg->bg_bits),
 995                                                         bit_off, bits_found);
 996
 997         return ret;
 998 }
 999
1000 static int ocfs2_alloc_dinode_update_counts(struct inode *inode,
1001                                        handle_t *handle,
1002                                        struct buffer_head *di_bh,
1003                                        u32 num_bits,
1004                                        u16 chain)
1005 {
1006         int ret;
1007         u32 tmp_used;
1008         struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
1009         struct ocfs2_chain_list *cl = (struct ocfs2_chain_list *) &di->id2.i_chain;
1010
1011         ret = ocfs2_journal_access(handle, inode, di_bh,
1012                                    OCFS2_JOURNAL_ACCESS_WRITE);
1013         if (ret < 0) {
1014                 mlog_errno(ret);
1015                 goto out;
1016         }
1017
1018         tmp_used = le32_to_cpu(di->id1.bitmap1.i_used);
1019         di->id1.bitmap1.i_used = cpu_to_le32(num_bits + tmp_used);
1020         le32_add_cpu(&cl->cl_recs[chain].c_free, -num_bits);
1021
1022         ret = ocfs2_journal_dirty(handle, di_bh);
1023         if (ret < 0)
1024                 mlog_errno(ret);
1025
1026 out:
1027         return ret;
1028 }
1029
1030 static int ocfs2_search_one_group(struct ocfs2_alloc_context *ac,
1031                                   handle_t *handle,
1032                                   u32 bits_wanted,
1033                                   u32 min_bits,
1034                                   u16 *bit_off,
1035                                   unsigned int *num_bits,
1036                                   u64 gd_blkno,
1037                                   u16 *bits_left)
1038 {
1039         int ret;
1040         u16 found;
1041         struct buffer_head *group_bh = NULL;
1042         struct ocfs2_group_desc *gd;
1043         struct inode *alloc_inode = ac->ac_inode;
1044
1045         ret = ocfs2_read_block(OCFS2_SB(alloc_inode->i_sb), gd_blkno,
1046                                &group_bh, OCFS2_BH_CACHED, alloc_inode);
1047         if (ret < 0) {
1048                 mlog_errno(ret);
1049                 return ret;
1050         }
1051
1052         gd = (struct ocfs2_group_desc *) group_bh->b_data;
1053         if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {
1054                 OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, gd);
1055                 ret = -EIO;
1056                 goto out;
1057         }
1058
1059         ret = ac->ac_group_search(alloc_inode, group_bh, bits_wanted, min_bits,
1060                                   bit_off, &found);
1061         if (ret < 0) {
1062                 if (ret != -ENOSPC)
1063                         mlog_errno(ret);
1064                 goto out;
1065         }
1066
1067         *num_bits = found;
1068
1069         ret = ocfs2_alloc_dinode_update_counts(alloc_inode, handle, ac->ac_bh,
1070                                                *num_bits,
1071                                                le16_to_cpu(gd->bg_chain));
1072         if (ret < 0) {
1073                 mlog_errno(ret);
1074                 goto out;
1075         }
1076
1077         ret = ocfs2_block_group_set_bits(handle, alloc_inode, gd, group_bh,
1078                                          *bit_off, *num_bits);
1079         if (ret < 0)
1080                 mlog_errno(ret);
1081
1082         *bits_left = le16_to_cpu(gd->bg_free_bits_count);
1083
1084 out:
1085         brelse(group_bh);
1086
1087         return ret;
1088 }
1089
1090 static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
1091                               handle_t *handle,
1092                               u32 bits_wanted,
1093                               u32 min_bits,
1094                               u16 *bit_off,
1095                               unsigned int *num_bits,
1096                               u64 *bg_blkno,
1097                               u16 *bits_left)
1098 {
1099         int status;
1100         u16 chain, tmp_bits;
1101         u32 tmp_used;
1102         u64 next_group;
1103         struct inode *alloc_inode = ac->ac_inode;
1104         struct buffer_head *group_bh = NULL;
1105         struct buffer_head *prev_group_bh = NULL;
1106         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) ac->ac_bh->b_data;
1107         struct ocfs2_chain_list *cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
1108         struct ocfs2_group_desc *bg;
1109
1110         chain = ac->ac_chain;
1111         mlog(0, "trying to alloc %u bits from chain %u, inode %llu\n",
1112              bits_wanted, chain,
1113              (unsigned long long)OCFS2_I(alloc_inode)->ip_blkno);
1114
1115         status = ocfs2_read_block(OCFS2_SB(alloc_inode->i_sb),
1116                                   le64_to_cpu(cl->cl_recs[chain].c_blkno),
1117                                   &group_bh, OCFS2_BH_CACHED, alloc_inode);
1118         if (status < 0) {
1119                 mlog_errno(status);
1120                 goto bail;
1121         }
1122         bg = (struct ocfs2_group_desc *) group_bh->b_data;
1123         status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);
1124         if (status) {
1125                 mlog_errno(status);
1126                 goto bail;
1127         }
1128
1129         status = -ENOSPC;
1130         /* for now, the chain search is a bit simplistic. We just use
1131          * the 1st group with any empty bits. */
1132         while ((status = ac->ac_group_search(alloc_inode, group_bh,
1133                                              bits_wanted, min_bits, bit_off,
1134                                              &tmp_bits)) == -ENOSPC) {
1135                 if (!bg->bg_next_group)
1136                         break;
1137
1138                 if (prev_group_bh) {
1139                         brelse(prev_group_bh);
1140                         prev_group_bh = NULL;
1141                 }
1142                 next_group = le64_to_cpu(bg->bg_next_group);
1143                 prev_group_bh = group_bh;
1144                 group_bh = NULL;
1145                 status = ocfs2_read_block(OCFS2_SB(alloc_inode->i_sb),
1146                                           next_group, &group_bh,
1147                                           OCFS2_BH_CACHED, alloc_inode);
1148                 if (status < 0) {
1149                         mlog_errno(status);
1150                         goto bail;
1151                 }
1152                 bg = (struct ocfs2_group_desc *) group_bh->b_data;
1153                 status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);
1154                 if (status) {
1155                         mlog_errno(status);
1156                         goto bail;
1157                 }
1158         }
1159         if (status < 0) {
1160                 if (status != -ENOSPC)
1161                         mlog_errno(status);
1162                 goto bail;
1163         }
1164
1165         mlog(0, "alloc succeeds: we give %u bits from block group %llu\n",
1166              tmp_bits, (unsigned long long)bg->bg_blkno);
1167
1168         *num_bits = tmp_bits;
1169
1170         BUG_ON(*num_bits == 0);
1171
1172         /*
1173          * Keep track of previous block descriptor read. When
1174          * we find a target, if we have read more than X
1175          * number of descriptors, and the target is reasonably
1176          * empty, relink him to top of his chain.
1177          *
1178          * We've read 0 extra blocks and only send one more to
1179          * the transaction, yet the next guy to search has a
1180          * much easier time.
1181          *
1182          * Do this *after* figuring out how many bits we're taking out
1183          * of our target group.
1184          */
1185         if (ac->ac_allow_chain_relink &&
1186             (prev_group_bh) &&
1187             (ocfs2_block_group_reasonably_empty(bg, *num_bits))) {
1188                 status = ocfs2_relink_block_group(handle, alloc_inode,
1189                                                   ac->ac_bh, group_bh,
1190                                                   prev_group_bh, chain);
1191                 if (status < 0) {
1192                         mlog_errno(status);
1193                         goto bail;
1194                 }
1195         }
1196
1197         /* Ok, claim our bits now: set the info on dinode, chainlist
1198          * and then the group */
1199         status = ocfs2_journal_access(handle,
1200                                       alloc_inode,
1201                                       ac->ac_bh,
1202                                       OCFS2_JOURNAL_ACCESS_WRITE);
1203         if (status < 0) {
1204                 mlog_errno(status);
1205                 goto bail;
1206         }
1207
1208         tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used);
1209         fe->id1.bitmap1.i_used = cpu_to_le32(*num_bits + tmp_used);
1210         le32_add_cpu(&cl->cl_recs[chain].c_free, -(*num_bits));
1211
1212         status = ocfs2_journal_dirty(handle,
1213                                      ac->ac_bh);
1214         if (status < 0) {
1215                 mlog_errno(status);
1216                 goto bail;
1217         }
1218
1219         status = ocfs2_block_group_set_bits(handle,
1220                                             alloc_inode,
1221                                             bg,
1222                                             group_bh,
1223                                             *bit_off,
1224                                             *num_bits);
1225         if (status < 0) {
1226                 mlog_errno(status);
1227                 goto bail;
1228         }
1229
1230         mlog(0, "Allocated %u bits from suballocator %llu\n", *num_bits,
1231              (unsigned long long)fe->i_blkno);
1232
1233         *bg_blkno = le64_to_cpu(bg->bg_blkno);
1234         *bits_left = le16_to_cpu(bg->bg_free_bits_count);
1235 bail:
1236         if (group_bh)
1237                 brelse(group_bh);
1238         if (prev_group_bh)
1239                 brelse(prev_group_bh);
1240
1241         mlog_exit(status);
1242         return status;
1243 }
1244
1245 /* will give out up to bits_wanted contiguous bits. */
1246 static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb,
1247                                      struct ocfs2_alloc_context *ac,
1248                                      handle_t *handle,
1249                                      u32 bits_wanted,
1250                                      u32 min_bits,
1251                                      u16 *bit_off,
1252                                      unsigned int *num_bits,
1253                                      u64 *bg_blkno)
1254 {
1255         int status;
1256         u16 victim, i;
1257         u16 bits_left = 0;
1258         u64 hint_blkno = ac->ac_last_group;
1259         struct ocfs2_chain_list *cl;
1260         struct ocfs2_dinode *fe;
1261
1262         mlog_entry_void();
1263
1264         BUG_ON(ac->ac_bits_given >= ac->ac_bits_wanted);
1265         BUG_ON(bits_wanted > (ac->ac_bits_wanted - ac->ac_bits_given));
1266         BUG_ON(!ac->ac_bh);
1267
1268         fe = (struct ocfs2_dinode *) ac->ac_bh->b_data;
1269         if (!OCFS2_IS_VALID_DINODE(fe)) {
1270                 OCFS2_RO_ON_INVALID_DINODE(osb->sb, fe);
1271                 status = -EIO;
1272                 goto bail;
1273         }
1274         if (le32_to_cpu(fe->id1.bitmap1.i_used) >=
1275             le32_to_cpu(fe->id1.bitmap1.i_total)) {
1276                 ocfs2_error(osb->sb, "Chain allocator dinode %llu has %u used "
1277                             "bits but only %u total.",
1278                             (unsigned long long)le64_to_cpu(fe->i_blkno),
1279                             le32_to_cpu(fe->id1.bitmap1.i_used),
1280                             le32_to_cpu(fe->id1.bitmap1.i_total));
1281                 status = -EIO;
1282                 goto bail;
1283         }
1284
1285         if (hint_blkno) {
1286                 /* Attempt to short-circuit the usual search mechanism
1287                  * by jumping straight to the most recently used
1288                  * allocation group. This helps us mantain some
1289                  * contiguousness across allocations. */
1290                 status = ocfs2_search_one_group(ac, handle, bits_wanted,
1291                                                 min_bits, bit_off, num_bits,
1292                                                 hint_blkno, &bits_left);
1293                 if (!status) {
1294                         /* Be careful to update *bg_blkno here as the
1295                          * caller is expecting it to be filled in, and
1296                          * ocfs2_search_one_group() won't do that for
1297                          * us. */
1298                         *bg_blkno = hint_blkno;
1299                         goto set_hint;
1300                 }
1301                 if (status < 0 && status != -ENOSPC) {
1302                         mlog_errno(status);
1303                         goto bail;
1304                 }
1305         }
1306
1307         cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
1308
1309         victim = ocfs2_find_victim_chain(cl);
1310         ac->ac_chain = victim;
1311         ac->ac_allow_chain_relink = 1;
1312
1313         status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits, bit_off,
1314                                     num_bits, bg_blkno, &bits_left);
1315         if (!status)
1316                 goto set_hint;
1317         if (status < 0 && status != -ENOSPC) {
1318                 mlog_errno(status);
1319                 goto bail;
1320         }
1321
1322         mlog(0, "Search of victim chain %u came up with nothing, "
1323              "trying all chains now.\n", victim);
1324
1325         /* If we didn't pick a good victim, then just default to
1326          * searching each chain in order. Don't allow chain relinking
1327          * because we only calculate enough journal credits for one
1328          * relink per alloc. */
1329         ac->ac_allow_chain_relink = 0;
1330         for (i = 0; i < le16_to_cpu(cl->cl_next_free_rec); i ++) {
1331                 if (i == victim)
1332                         continue;
1333                 if (!cl->cl_recs[i].c_free)
1334                         continue;
1335
1336                 ac->ac_chain = i;
1337                 status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits,
1338                                             bit_off, num_bits, bg_blkno,
1339                                             &bits_left);
1340                 if (!status)
1341                         break;
1342                 if (status < 0 && status != -ENOSPC) {
1343                         mlog_errno(status);
1344                         goto bail;
1345                 }
1346         }
1347
1348 set_hint:
1349         if (status != -ENOSPC) {
1350                 /* If the next search of this group is not likely to
1351                  * yield a suitable extent, then we reset the last
1352                  * group hint so as to not waste a disk read */
1353                 if (bits_left < min_bits)
1354                         ac->ac_last_group = 0;
1355                 else
1356                         ac->ac_last_group = *bg_blkno;
1357         }
1358
1359 bail:
1360         mlog_exit(status);
1361         return status;
1362 }
1363
1364 int ocfs2_claim_metadata(struct ocfs2_super *osb,
1365                          handle_t *handle,
1366                          struct ocfs2_alloc_context *ac,
1367                          u32 bits_wanted,
1368                          u16 *suballoc_bit_start,
1369                          unsigned int *num_bits,
1370                          u64 *blkno_start)
1371 {
1372         int status;
1373         u64 bg_blkno;
1374
1375         BUG_ON(!ac);
1376         BUG_ON(ac->ac_bits_wanted < (ac->ac_bits_given + bits_wanted));
1377         BUG_ON(ac->ac_which != OCFS2_AC_USE_META);
1378
1379         status = ocfs2_claim_suballoc_bits(osb,
1380                                            ac,
1381                                            handle,
1382                                            bits_wanted,
1383                                            1,
1384                                            suballoc_bit_start,
1385                                            num_bits,
1386                                            &bg_blkno);
1387         if (status < 0) {
1388                 mlog_errno(status);
1389                 goto bail;
1390         }
1391         atomic_inc(&osb->alloc_stats.bg_allocs);
1392
1393         *blkno_start = bg_blkno + (u64) *suballoc_bit_start;
1394         ac->ac_bits_given += (*num_bits);
1395         status = 0;
1396 bail:
1397         mlog_exit(status);
1398         return status;
1399 }
1400
1401 int ocfs2_claim_new_inode(struct ocfs2_super *osb,
1402                           handle_t *handle,
1403                           struct ocfs2_alloc_context *ac,
1404                           u16 *suballoc_bit,
1405                           u64 *fe_blkno)
1406 {
1407         int status;
1408         unsigned int num_bits;
1409         u64 bg_blkno;
1410
1411         mlog_entry_void();
1412
1413         BUG_ON(!ac);
1414         BUG_ON(ac->ac_bits_given != 0);
1415         BUG_ON(ac->ac_bits_wanted != 1);
1416         BUG_ON(ac->ac_which != OCFS2_AC_USE_INODE);
1417
1418         status = ocfs2_claim_suballoc_bits(osb,
1419                                            ac,
1420                                            handle,
1421                                            1,
1422                                            1,
1423                                            suballoc_bit,
1424                                            &num_bits,
1425                                            &bg_blkno);
1426         if (status < 0) {
1427                 mlog_errno(status);
1428                 goto bail;
1429         }
1430         atomic_inc(&osb->alloc_stats.bg_allocs);
1431
1432         BUG_ON(num_bits != 1);
1433
1434         *fe_blkno = bg_blkno + (u64) (*suballoc_bit);
1435         ac->ac_bits_given++;
1436         status = 0;
1437 bail:
1438         mlog_exit(status);
1439         return status;
1440 }
1441
1442 /* translate a group desc. blkno and it's bitmap offset into
1443  * disk cluster offset. */
1444 static inline u32 ocfs2_desc_bitmap_to_cluster_off(struct inode *inode,
1445                                                    u64 bg_blkno,
1446                                                    u16 bg_bit_off)
1447 {
1448         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1449         u32 cluster = 0;
1450
1451         BUG_ON(!ocfs2_is_cluster_bitmap(inode));
1452
1453         if (bg_blkno != osb->first_cluster_group_blkno)
1454                 cluster = ocfs2_blocks_to_clusters(inode->i_sb, bg_blkno);
1455         cluster += (u32) bg_bit_off;
1456         return cluster;
1457 }
1458
1459 /* given a cluster offset, calculate which block group it belongs to
1460  * and return that block offset. */
1461 static inline u64 ocfs2_which_cluster_group(struct inode *inode,
1462                                             u32 cluster)
1463 {
1464         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1465         u32 group_no;
1466
1467         BUG_ON(!ocfs2_is_cluster_bitmap(inode));
1468
1469         group_no = cluster / osb->bitmap_cpg;
1470         if (!group_no)
1471                 return osb->first_cluster_group_blkno;
1472         return ocfs2_clusters_to_blocks(inode->i_sb,
1473                                         group_no * osb->bitmap_cpg);
1474 }
1475
1476 /* given the block number of a cluster start, calculate which cluster
1477  * group and descriptor bitmap offset that corresponds to. */
1478 static inline void ocfs2_block_to_cluster_group(struct inode *inode,
1479                                                 u64 data_blkno,
1480                                                 u64 *bg_blkno,
1481                                                 u16 *bg_bit_off)
1482 {
1483         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
1484         u32 data_cluster = ocfs2_blocks_to_clusters(osb->sb, data_blkno);
1485
1486         BUG_ON(!ocfs2_is_cluster_bitmap(inode));
1487
1488         *bg_blkno = ocfs2_which_cluster_group(inode,
1489                                               data_cluster);
1490
1491         if (*bg_blkno == osb->first_cluster_group_blkno)
1492                 *bg_bit_off = (u16) data_cluster;
1493         else
1494                 *bg_bit_off = (u16) ocfs2_blocks_to_clusters(osb->sb,
1495                                                              data_blkno - *bg_blkno);
1496 }
1497
1498 /*
1499  * min_bits - minimum contiguous chunk from this total allocation we
1500  * can handle. set to what we asked for originally for a full
1501  * contig. allocation, set to '1' to indicate we can deal with extents
1502  * of any size.
1503  */
1504 int ocfs2_claim_clusters(struct ocfs2_super *osb,
1505                          handle_t *handle,
1506                          struct ocfs2_alloc_context *ac,
1507                          u32 min_clusters,
1508                          u32 *cluster_start,
1509                          u32 *num_clusters)
1510 {
1511         int status;
1512         unsigned int bits_wanted = ac->ac_bits_wanted - ac->ac_bits_given;
1513         u64 bg_blkno = 0;
1514         u16 bg_bit_off;
1515
1516         mlog_entry_void();
1517
1518         BUG_ON(!ac);
1519         BUG_ON(ac->ac_bits_given >= ac->ac_bits_wanted);
1520
1521         BUG_ON(ac->ac_which != OCFS2_AC_USE_LOCAL
1522                && ac->ac_which != OCFS2_AC_USE_MAIN);
1523
1524         if (ac->ac_which == OCFS2_AC_USE_LOCAL) {
1525                 status = ocfs2_claim_local_alloc_bits(osb,
1526                                                       handle,
1527                                                       ac,
1528                                                       bits_wanted,
1529                                                       cluster_start,
1530                                                       num_clusters);
1531                 if (!status)
1532                         atomic_inc(&osb->alloc_stats.local_data);
1533         } else {
1534                 if (min_clusters > (osb->bitmap_cpg - 1)) {
1535                         /* The only paths asking for contiguousness
1536                          * should know about this already. */
1537                         mlog(ML_ERROR, "minimum allocation requested exceeds "
1538                                        "group bitmap size!");
1539                         status = -ENOSPC;
1540                         goto bail;
1541                 }
1542                 /* clamp the current request down to a realistic size. */
1543                 if (bits_wanted > (osb->bitmap_cpg - 1))
1544                         bits_wanted = osb->bitmap_cpg - 1;
1545
1546                 status = ocfs2_claim_suballoc_bits(osb,
1547                                                    ac,
1548                                                    handle,
1549                                                    bits_wanted,
1550                                                    min_clusters,
1551                                                    &bg_bit_off,
1552                                                    num_clusters,
1553                                                    &bg_blkno);
1554                 if (!status) {
1555                         *cluster_start =
1556                                 ocfs2_desc_bitmap_to_cluster_off(ac->ac_inode,
1557                                                                  bg_blkno,
1558                                                                  bg_bit_off);
1559                         atomic_inc(&osb->alloc_stats.bitmap_data);
1560                 }
1561         }
1562         if (status < 0) {
1563                 if (status != -ENOSPC)
1564                         mlog_errno(status);
1565                 goto bail;
1566         }
1567
1568         ac->ac_bits_given += *num_clusters;
1569
1570 bail:
1571         mlog_exit(status);
1572         return status;
1573 }
1574
1575 static inline int ocfs2_block_group_clear_bits(handle_t *handle,
1576                                                struct inode *alloc_inode,
1577                                                struct ocfs2_group_desc *bg,
1578                                                struct buffer_head *group_bh,
1579                                                unsigned int bit_off,
1580                                                unsigned int num_bits)
1581 {
1582         int status;
1583         unsigned int tmp;
1584         int journal_type = OCFS2_JOURNAL_ACCESS_WRITE;
1585         struct ocfs2_group_desc *undo_bg = NULL;
1586
1587         mlog_entry_void();
1588
1589         if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {
1590                 OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);
1591                 status = -EIO;
1592                 goto bail;
1593         }
1594
1595         mlog(0, "off = %u, num = %u\n", bit_off, num_bits);
1596
1597         if (ocfs2_is_cluster_bitmap(alloc_inode))
1598                 journal_type = OCFS2_JOURNAL_ACCESS_UNDO;
1599
1600         status = ocfs2_journal_access(handle, alloc_inode, group_bh,
1601                                       journal_type);
1602         if (status < 0) {
1603                 mlog_errno(status);
1604                 goto bail;
1605         }
1606
1607         if (ocfs2_is_cluster_bitmap(alloc_inode))
1608                 undo_bg = (struct ocfs2_group_desc *) bh2jh(group_bh)->b_committed_data;
1609
1610         tmp = num_bits;
1611         while(tmp--) {
1612                 ocfs2_clear_bit((bit_off + tmp),
1613                                 (unsigned long *) bg->bg_bitmap);
1614                 if (ocfs2_is_cluster_bitmap(alloc_inode))
1615                         ocfs2_set_bit(bit_off + tmp,
1616                                       (unsigned long *) undo_bg->bg_bitmap);
1617         }
1618         le16_add_cpu(&bg->bg_free_bits_count, num_bits);
1619
1620         status = ocfs2_journal_dirty(handle, group_bh);
1621         if (status < 0)
1622                 mlog_errno(status);
1623 bail:
1624         return status;
1625 }
1626
1627 /*
1628  * expects the suballoc inode to already be locked.
1629  */
1630 static int ocfs2_free_suballoc_bits(handle_t *handle,
1631                                     struct inode *alloc_inode,
1632                                     struct buffer_head *alloc_bh,
1633                                     unsigned int start_bit,
1634                                     u64 bg_blkno,
1635                                     unsigned int count)
1636 {
1637         int status = 0;
1638         u32 tmp_used;
1639         struct ocfs2_super *osb = OCFS2_SB(alloc_inode->i_sb);
1640         struct ocfs2_dinode *fe = (struct ocfs2_dinode *) alloc_bh->b_data;
1641         struct ocfs2_chain_list *cl = &fe->id2.i_chain;
1642         struct buffer_head *group_bh = NULL;
1643         struct ocfs2_group_desc *group;
1644
1645         mlog_entry_void();
1646
1647         if (!OCFS2_IS_VALID_DINODE(fe)) {
1648                 OCFS2_RO_ON_INVALID_DINODE(alloc_inode->i_sb, fe);
1649                 status = -EIO;
1650                 goto bail;
1651         }
1652         BUG_ON((count + start_bit) > ocfs2_bits_per_group(cl));
1653
1654         mlog(0, "%llu: freeing %u bits from group %llu, starting at %u\n",
1655              (unsigned long long)OCFS2_I(alloc_inode)->ip_blkno, count,
1656              (unsigned long long)bg_blkno, start_bit);
1657
1658         status = ocfs2_read_block(osb, bg_blkno, &group_bh, OCFS2_BH_CACHED,
1659                                   alloc_inode);
1660         if (status < 0) {
1661                 mlog_errno(status);
1662                 goto bail;
1663         }
1664
1665         group = (struct ocfs2_group_desc *) group_bh->b_data;
1666         status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, group);
1667         if (status) {
1668                 mlog_errno(status);
1669                 goto bail;
1670         }
1671         BUG_ON((count + start_bit) > le16_to_cpu(group->bg_bits));
1672
1673         status = ocfs2_block_group_clear_bits(handle, alloc_inode,
1674                                               group, group_bh,
1675                                               start_bit, count);
1676         if (status < 0) {
1677                 mlog_errno(status);
1678                 goto bail;
1679         }
1680
1681         status = ocfs2_journal_access(handle, alloc_inode, alloc_bh,
1682                                       OCFS2_JOURNAL_ACCESS_WRITE);
1683         if (status < 0) {
1684                 mlog_errno(status);
1685                 goto bail;
1686         }
1687
1688         le32_add_cpu(&cl->cl_recs[le16_to_cpu(group->bg_chain)].c_free,
1689                      count);
1690         tmp_used = le32_to_cpu(fe->id1.bitmap1.i_used);
1691         fe->id1.bitmap1.i_used = cpu_to_le32(tmp_used - count);
1692
1693         status = ocfs2_journal_dirty(handle, alloc_bh);
1694         if (status < 0) {
1695                 mlog_errno(status);
1696                 goto bail;
1697         }
1698
1699 bail:
1700         if (group_bh)
1701                 brelse(group_bh);
1702
1703         mlog_exit(status);
1704         return status;
1705 }
1706
1707 static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
1708 {
1709         u64 group = block - (u64) bit;
1710
1711         return group;
1712 }
1713
1714 int ocfs2_free_dinode(handle_t *handle,
1715                       struct inode *inode_alloc_inode,
1716                       struct buffer_head *inode_alloc_bh,
1717                       struct ocfs2_dinode *di)
1718 {
1719         u64 blk = le64_to_cpu(di->i_blkno);
1720         u16 bit = le16_to_cpu(di->i_suballoc_bit);
1721         u64 bg_blkno = ocfs2_which_suballoc_group(blk, bit);
1722
1723         return ocfs2_free_suballoc_bits(handle, inode_alloc_inode,
1724                                         inode_alloc_bh, bit, bg_blkno, 1);
1725 }
1726
1727 int ocfs2_free_extent_block(handle_t *handle,
1728                             struct inode *eb_alloc_inode,
1729                             struct buffer_head *eb_alloc_bh,
1730                             struct ocfs2_extent_block *eb)
1731 {
1732         u64 blk = le64_to_cpu(eb->h_blkno);
1733         u16 bit = le16_to_cpu(eb->h_suballoc_bit);
1734         u64 bg_blkno = ocfs2_which_suballoc_group(blk, bit);
1735
1736         return ocfs2_free_suballoc_bits(handle, eb_alloc_inode, eb_alloc_bh,
1737                                         bit, bg_blkno, 1);
1738 }
1739
1740 int ocfs2_free_clusters(handle_t *handle,
1741                        struct inode *bitmap_inode,
1742                        struct buffer_head *bitmap_bh,
1743                        u64 start_blk,
1744                        unsigned int num_clusters)
1745 {
1746         int status;
1747         u16 bg_start_bit;
1748         u64 bg_blkno;
1749         struct ocfs2_dinode *fe;
1750
1751         /* You can't ever have a contiguous set of clusters
1752          * bigger than a block group bitmap so we never have to worry
1753          * about looping on them. */
1754
1755         mlog_entry_void();
1756
1757         /* This is expensive. We can safely remove once this stuff has
1758          * gotten tested really well. */
1759         BUG_ON(start_blk != ocfs2_clusters_to_blocks(bitmap_inode->i_sb, ocfs2_blocks_to_clusters(bitmap_inode->i_sb, start_blk)));
1760
1761         fe = (struct ocfs2_dinode *) bitmap_bh->b_data;
1762
1763         ocfs2_block_to_cluster_group(bitmap_inode, start_blk, &bg_blkno,
1764                                      &bg_start_bit);
1765
1766         mlog(0, "want to free %u clusters starting at block %llu\n",
1767              num_clusters, (unsigned long long)start_blk);
1768         mlog(0, "bg_blkno = %llu, bg_start_bit = %u\n",
1769              (unsigned long long)bg_blkno, bg_start_bit);
1770
1771         status = ocfs2_free_suballoc_bits(handle, bitmap_inode, bitmap_bh,
1772                                           bg_start_bit, bg_blkno,
1773                                           num_clusters);
1774         if (status < 0)
1775                 mlog_errno(status);
1776
1777         mlog_exit(status);
1778         return status;
1779 }
1780
1781 static inline void ocfs2_debug_bg(struct ocfs2_group_desc *bg)
1782 {
1783         printk("Block Group:\n");
1784         printk("bg_signature:       %s\n", bg->bg_signature);
1785         printk("bg_size:            %u\n", bg->bg_size);
1786         printk("bg_bits:            %u\n", bg->bg_bits);
1787         printk("bg_free_bits_count: %u\n", bg->bg_free_bits_count);
1788         printk("bg_chain:           %u\n", bg->bg_chain);
1789         printk("bg_generation:      %u\n", le32_to_cpu(bg->bg_generation));
1790         printk("bg_next_group:      %llu\n",
1791                (unsigned long long)bg->bg_next_group);
1792         printk("bg_parent_dinode:   %llu\n",
1793                (unsigned long long)bg->bg_parent_dinode);
1794         printk("bg_blkno:           %llu\n",
1795                (unsigned long long)bg->bg_blkno);
1796 }
1797
1798 static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe)
1799 {
1800         int i;
1801
1802         printk("Suballoc Inode %llu:\n", (unsigned long long)fe->i_blkno);
1803         printk("i_signature:                  %s\n", fe->i_signature);
1804         printk("i_size:                       %llu\n",
1805                (unsigned long long)fe->i_size);
1806         printk("i_clusters:                   %u\n", fe->i_clusters);
1807         printk("i_generation:                 %u\n",
1808                le32_to_cpu(fe->i_generation));
1809         printk("id1.bitmap1.i_used:           %u\n",
1810                le32_to_cpu(fe->id1.bitmap1.i_used));
1811         printk("id1.bitmap1.i_total:          %u\n",
1812                le32_to_cpu(fe->id1.bitmap1.i_total));
1813         printk("id2.i_chain.cl_cpg:           %u\n", fe->id2.i_chain.cl_cpg);
1814         printk("id2.i_chain.cl_bpc:           %u\n", fe->id2.i_chain.cl_bpc);
1815         printk("id2.i_chain.cl_count:         %u\n", fe->id2.i_chain.cl_count);
1816         printk("id2.i_chain.cl_next_free_rec: %u\n",
1817                fe->id2.i_chain.cl_next_free_rec);
1818         for(i = 0; i < fe->id2.i_chain.cl_next_free_rec; i++) {
1819                 printk("fe->id2.i_chain.cl_recs[%d].c_free:  %u\n", i,
1820                        fe->id2.i_chain.cl_recs[i].c_free);
1821                 printk("fe->id2.i_chain.cl_recs[%d].c_total: %u\n", i,
1822                        fe->id2.i_chain.cl_recs[i].c_total);
1823                 printk("fe->id2.i_chain.cl_recs[%d].c_blkno: %llu\n", i,
1824                        (unsigned long long)fe->id2.i_chain.cl_recs[i].c_blkno);
1825         }
1826 }