fs/nilfs2/alloc.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * alloc.c - NILFS dat/inode allocator
   4  *
   5  * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Originally written by Koji Sato.
   8  * Two allocators were unified by Ryusuke Konishi and Amagai Yoshiji.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/buffer_head.h>
  13 #include <linux/fs.h>
  14 #include <linux/bitops.h>
  15 #include <linux/slab.h>
  16 #include "mdt.h"
  17 #include "alloc.h"
  18
  19
  20 /**
  21  * nilfs_palloc_groups_per_desc_block - get the number of groups that a group
  22  *                                      descriptor block can maintain
  23  * @inode: inode of metadata file using this allocator
  24  */
  25 static inline unsigned long
  26 nilfs_palloc_groups_per_desc_block(const struct inode *inode)
  27 {
  28         return i_blocksize(inode) /
  29                 sizeof(struct nilfs_palloc_group_desc);
  30 }
  31
  32 /**
  33  * nilfs_palloc_groups_count - get maximum number of groups
  34  * @inode: inode of metadata file using this allocator
  35  */
  36 static inline unsigned long
  37 nilfs_palloc_groups_count(const struct inode *inode)
  38 {
  39         return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
  40 }
  41
  42 /**
  43  * nilfs_palloc_init_blockgroup - initialize private variables for allocator
  44  * @inode: inode of metadata file using this allocator
  45  * @entry_size: size of the persistent object
  46  */
  47 int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned int entry_size)
  48 {
  49         struct nilfs_mdt_info *mi = NILFS_MDT(inode);
  50
  51         mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
  52         if (!mi->mi_bgl)
  53                 return -ENOMEM;
  54
  55         bgl_lock_init(mi->mi_bgl);
  56
  57         nilfs_mdt_set_entry_size(inode, entry_size, 0);
  58
  59         mi->mi_blocks_per_group =
  60                 DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
  61                              mi->mi_entries_per_block) + 1;
  62                 /*
  63                  * Number of blocks in a group including entry blocks
  64                  * and a bitmap block
  65                  */
  66         mi->mi_blocks_per_desc_block =
  67                 nilfs_palloc_groups_per_desc_block(inode) *
  68                 mi->mi_blocks_per_group + 1;
  69                 /*
  70                  * Number of blocks per descriptor including the
  71                  * descriptor block
  72                  */
  73         return 0;
  74 }
  75
  76 /**
  77  * nilfs_palloc_group - get group number and offset from an entry number
  78  * @inode: inode of metadata file using this allocator
  79  * @nr: serial number of the entry (e.g. inode number)
  80  * @offset: pointer to store offset number in the group
  81  */
  82 static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
  83                                         unsigned long *offset)
  84 {
  85         __u64 group = nr;
  86
  87         *offset = do_div(group, nilfs_palloc_entries_per_group(inode));
  88         return group;
  89 }
  90
  91 /**
  92  * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
  93  * @inode: inode of metadata file using this allocator
  94  * @group: group number
  95  *
  96  * nilfs_palloc_desc_blkoff() returns block offset of the descriptor
  97  * block which contains a descriptor of the specified group.
  98  */
  99 static unsigned long
 100 nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
 101 {
 102         unsigned long desc_block =
 103                 group / nilfs_palloc_groups_per_desc_block(inode);
 104         return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
 105 }
 106
 107 /**
 108  * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
 109  * @inode: inode of metadata file using this allocator
 110  * @group: group number
 111  *
 112  * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
 113  * block used to allocate/deallocate entries in the specified group.
 114  */
 115 static unsigned long
 116 nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
 117 {
 118         unsigned long desc_offset =
 119                 group % nilfs_palloc_groups_per_desc_block(inode);
 120         return nilfs_palloc_desc_blkoff(inode, group) + 1 +
 121                 desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
 122 }
 123
 124 /**
 125  * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
 126  * @desc: pointer to descriptor structure for the group
 127  * @lock: spin lock protecting @desc
 128  */
 129 static unsigned long
 130 nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
 131                                spinlock_t *lock)
 132 {
 133         unsigned long nfree;
 134
 135         spin_lock(lock);
 136         nfree = le32_to_cpu(desc->pg_nfrees);
 137         spin_unlock(lock);
 138         return nfree;
 139 }
 140
 141 /**
 142  * nilfs_palloc_group_desc_add_entries - adjust count of free entries
 143  * @desc: pointer to descriptor structure for the group
 144  * @lock: spin lock protecting @desc
 145  * @n: delta to be added
 146  */
 147 static u32
 148 nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
 149                                     spinlock_t *lock, u32 n)
 150 {
 151         u32 nfree;
 152
 153         spin_lock(lock);
 154         le32_add_cpu(&desc->pg_nfrees, n);
 155         nfree = le32_to_cpu(desc->pg_nfrees);
 156         spin_unlock(lock);
 157         return nfree;
 158 }
 159
 160 /**
 161  * nilfs_palloc_entry_blkoff - get block offset of an entry block
 162  * @inode: inode of metadata file using this allocator
 163  * @nr: serial number of the entry (e.g. inode number)
 164  */
 165 static unsigned long
 166 nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
 167 {
 168         unsigned long group, group_offset;
 169
 170         group = nilfs_palloc_group(inode, nr, &group_offset);
 171
 172         return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
 173                 group_offset / NILFS_MDT(inode)->mi_entries_per_block;
 174 }
 175
 176 /**
 177  * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
 178  * @inode: inode of metadata file
 179  * @bh: buffer head of the buffer to be initialized
 180  * @kaddr: kernel address mapped for the page including the buffer
 181  */
 182 static void nilfs_palloc_desc_block_init(struct inode *inode,
 183                                          struct buffer_head *bh, void *kaddr)
 184 {
 185         struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
 186         unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
 187         __le32 nfrees;
 188
 189         nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
 190         while (n-- > 0) {
 191                 desc->pg_nfrees = nfrees;
 192                 desc++;
 193         }
 194 }
 195
 196 static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
 197                                   int create,
 198                                   void (*init_block)(struct inode *,
 199                                                      struct buffer_head *,
 200                                                      void *),
 201                                   struct buffer_head **bhp,
 202                                   struct nilfs_bh_assoc *prev,
 203                                   spinlock_t *lock)
 204 {
 205         int ret;
 206
 207         spin_lock(lock);
 208         if (prev->bh && blkoff == prev->blkoff) {
 209                 get_bh(prev->bh);
 210                 *bhp = prev->bh;
 211                 spin_unlock(lock);
 212                 return 0;
 213         }
 214         spin_unlock(lock);
 215
 216         ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
 217         if (!ret) {
 218                 spin_lock(lock);
 219                 /*
 220                  * The following code must be safe for change of the
 221                  * cache contents during the get block call.
 222                  */
 223                 brelse(prev->bh);
 224                 get_bh(*bhp);
 225                 prev->bh = *bhp;
 226                 prev->blkoff = blkoff;
 227                 spin_unlock(lock);
 228         }
 229         return ret;
 230 }
 231
 232 /**
 233  * nilfs_palloc_delete_block - delete a block on the persistent allocator file
 234  * @inode: inode of metadata file using this allocator
 235  * @blkoff: block offset
 236  * @prev: nilfs_bh_assoc struct of the last used buffer
 237  * @lock: spin lock protecting @prev
 238  */
 239 static int nilfs_palloc_delete_block(struct inode *inode, unsigned long blkoff,
 240                                      struct nilfs_bh_assoc *prev,
 241                                      spinlock_t *lock)
 242 {
 243         spin_lock(lock);
 244         if (prev->bh && blkoff == prev->blkoff) {
 245                 brelse(prev->bh);
 246                 prev->bh = NULL;
 247         }
 248         spin_unlock(lock);
 249         return nilfs_mdt_delete_block(inode, blkoff);
 250 }
 251
 252 /**
 253  * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
 254  * @inode: inode of metadata file using this allocator
 255  * @group: group number
 256  * @create: create flag
 257  * @bhp: pointer to store the resultant buffer head
 258  */
 259 static int nilfs_palloc_get_desc_block(struct inode *inode,
 260                                        unsigned long group,
 261                                        int create, struct buffer_head **bhp)
 262 {
 263         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 264
 265         return nilfs_palloc_get_block(inode,
 266                                       nilfs_palloc_desc_blkoff(inode, group),
 267                                       create, nilfs_palloc_desc_block_init,
 268                                       bhp, &cache->prev_desc, &cache->lock);
 269 }
 270
 271 /**
 272  * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
 273  * @inode: inode of metadata file using this allocator
 274  * @group: group number
 275  * @create: create flag
 276  * @bhp: pointer to store the resultant buffer head
 277  */
 278 static int nilfs_palloc_get_bitmap_block(struct inode *inode,
 279                                          unsigned long group,
 280                                          int create, struct buffer_head **bhp)
 281 {
 282         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 283
 284         return nilfs_palloc_get_block(inode,
 285                                       nilfs_palloc_bitmap_blkoff(inode, group),
 286                                       create, NULL, bhp,
 287                                       &cache->prev_bitmap, &cache->lock);
 288 }
 289
 290 /**
 291  * nilfs_palloc_delete_bitmap_block - delete a bitmap block
 292  * @inode: inode of metadata file using this allocator
 293  * @group: group number
 294  */
 295 static int nilfs_palloc_delete_bitmap_block(struct inode *inode,
 296                                             unsigned long group)
 297 {
 298         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 299
 300         return nilfs_palloc_delete_block(inode,
 301                                          nilfs_palloc_bitmap_blkoff(inode,
 302                                                                     group),
 303                                          &cache->prev_bitmap, &cache->lock);
 304 }
 305
 306 /**
 307  * nilfs_palloc_get_entry_block - get buffer head of an entry block
 308  * @inode: inode of metadata file using this allocator
 309  * @nr: serial number of the entry (e.g. inode number)
 310  * @create: create flag
 311  * @bhp: pointer to store the resultant buffer head
 312  */
 313 int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
 314                                  int create, struct buffer_head **bhp)
 315 {
 316         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 317
 318         return nilfs_palloc_get_block(inode,
 319                                       nilfs_palloc_entry_blkoff(inode, nr),
 320                                       create, NULL, bhp,
 321                                       &cache->prev_entry, &cache->lock);
 322 }
 323
 324 /**
 325  * nilfs_palloc_delete_entry_block - delete an entry block
 326  * @inode: inode of metadata file using this allocator
 327  * @nr: serial number of the entry
 328  */
 329 static int nilfs_palloc_delete_entry_block(struct inode *inode, __u64 nr)
 330 {
 331         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 332
 333         return nilfs_palloc_delete_block(inode,
 334                                          nilfs_palloc_entry_blkoff(inode, nr),
 335                                          &cache->prev_entry, &cache->lock);
 336 }
 337
 338 /**
 339  * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
 340  * @inode: inode of metadata file using this allocator
 341  * @group: group number
 342  * @bh: buffer head of the buffer storing the group descriptor block
 343  * @kaddr: kernel address mapped for the page including the buffer
 344  */
 345 static struct nilfs_palloc_group_desc *
 346 nilfs_palloc_block_get_group_desc(const struct inode *inode,
 347                                   unsigned long group,
 348                                   const struct buffer_head *bh, void *kaddr)
 349 {
 350         return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
 351                 group % nilfs_palloc_groups_per_desc_block(inode);
 352 }
 353
 354 /**
 355  * nilfs_palloc_block_get_entry - get kernel address of an entry
 356  * @inode: inode of metadata file using this allocator
 357  * @nr: serial number of the entry (e.g. inode number)
 358  * @bh: buffer head of the buffer storing the entry block
 359  * @kaddr: kernel address mapped for the page including the buffer
 360  */
 361 void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
 362                                    const struct buffer_head *bh, void *kaddr)
 363 {
 364         unsigned long entry_offset, group_offset;
 365
 366         nilfs_palloc_group(inode, nr, &group_offset);
 367         entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
 368
 369         return kaddr + bh_offset(bh) +
 370                 entry_offset * NILFS_MDT(inode)->mi_entry_size;
 371 }
 372
 373 /**
 374  * nilfs_palloc_find_available_slot - find available slot in a group
 375  * @bitmap: bitmap of the group
 376  * @target: offset number of an entry in the group (start point)
 377  * @bsize: size in bits
 378  * @lock: spin lock protecting @bitmap
 379  */
 380 static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
 381                                             unsigned long target,
 382                                             unsigned int bsize,
 383                                             spinlock_t *lock)
 384 {
 385         int pos, end = bsize;
 386
 387         if (likely(target < bsize)) {
 388                 pos = target;
 389                 do {
 390                         pos = nilfs_find_next_zero_bit(bitmap, end, pos);
 391                         if (pos >= end)
 392                                 break;
 393                         if (!nilfs_set_bit_atomic(lock, pos, bitmap))
 394                                 return pos;
 395                 } while (++pos < end);
 396
 397                 end = target;
 398         }
 399
 400         /* wrap around */
 401         for (pos = 0; pos < end; pos++) {
 402                 pos = nilfs_find_next_zero_bit(bitmap, end, pos);
 403                 if (pos >= end)
 404                         break;
 405                 if (!nilfs_set_bit_atomic(lock, pos, bitmap))
 406                         return pos;
 407         }
 408
 409         return -ENOSPC;
 410 }
 411
 412 /**
 413  * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
 414  *                                          in a group descriptor block
 415  * @inode: inode of metadata file using this allocator
 416  * @curr: current group number
 417  * @max: maximum number of groups
 418  */
 419 static unsigned long
 420 nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
 421                                        unsigned long curr, unsigned long max)
 422 {
 423         return min_t(unsigned long,
 424                      nilfs_palloc_groups_per_desc_block(inode) -
 425                      curr % nilfs_palloc_groups_per_desc_block(inode),
 426                      max - curr + 1);
 427 }
 428
 429 /**
 430  * nilfs_palloc_count_desc_blocks - count descriptor blocks number
 431  * @inode: inode of metadata file using this allocator
 432  * @desc_blocks: descriptor blocks number [out]
 433  */
 434 static int nilfs_palloc_count_desc_blocks(struct inode *inode,
 435                                             unsigned long *desc_blocks)
 436 {
 437         __u64 blknum;
 438         int ret;
 439
 440         ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
 441         if (likely(!ret))
 442                 *desc_blocks = DIV_ROUND_UP(
 443                         (unsigned long)blknum,
 444                         NILFS_MDT(inode)->mi_blocks_per_desc_block);
 445         return ret;
 446 }
 447
 448 /**
 449  * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
 450  *                                      MDT file growing
 451  * @inode: inode of metadata file using this allocator
 452  * @desc_blocks: known current descriptor blocks count
 453  */
 454 static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
 455                                                     unsigned long desc_blocks)
 456 {
 457         return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
 458                         nilfs_palloc_groups_count(inode);
 459 }
 460
 461 /**
 462  * nilfs_palloc_count_max_entries - count max number of entries that can be
 463  *                                      described by descriptor blocks count
 464  * @inode: inode of metadata file using this allocator
 465  * @nused: current number of used entries
 466  * @nmaxp: max number of entries [out]
 467  */
 468 int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
 469 {
 470         unsigned long desc_blocks = 0;
 471         u64 entries_per_desc_block, nmax;
 472         int err;
 473
 474         err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
 475         if (unlikely(err))
 476                 return err;
 477
 478         entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
 479                                 nilfs_palloc_groups_per_desc_block(inode);
 480         nmax = entries_per_desc_block * desc_blocks;
 481
 482         if (nused == nmax &&
 483                         nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
 484                 nmax += entries_per_desc_block;
 485
 486         if (nused > nmax)
 487                 return -ERANGE;
 488
 489         *nmaxp = nmax;
 490         return 0;
 491 }
 492
 493 /**
 494  * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
 495  * @inode: inode of metadata file using this allocator
 496  * @req: nilfs_palloc_req structure exchanged for the allocation
 497  */
 498 int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
 499                                      struct nilfs_palloc_req *req)
 500 {
 501         struct buffer_head *desc_bh, *bitmap_bh;
 502         struct nilfs_palloc_group_desc *desc;
 503         unsigned char *bitmap;
 504         void *desc_kaddr, *bitmap_kaddr;
 505         unsigned long group, maxgroup, ngroups;
 506         unsigned long group_offset, maxgroup_offset;
 507         unsigned long n, entries_per_group;
 508         unsigned long i, j;
 509         spinlock_t *lock;
 510         int pos, ret;
 511
 512         ngroups = nilfs_palloc_groups_count(inode);
 513         maxgroup = ngroups - 1;
 514         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 515         entries_per_group = nilfs_palloc_entries_per_group(inode);
 516
 517         for (i = 0; i < ngroups; i += n) {
 518                 if (group >= ngroups) {
 519                         /* wrap around */
 520                         group = 0;
 521                         maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
 522                                                       &maxgroup_offset) - 1;
 523                 }
 524                 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
 525                 if (ret < 0)
 526                         return ret;
 527                 desc_kaddr = kmap(desc_bh->b_page);
 528                 desc = nilfs_palloc_block_get_group_desc(
 529                         inode, group, desc_bh, desc_kaddr);
 530                 n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
 531                                                            maxgroup);
 532                 for (j = 0; j < n; j++, desc++, group++) {
 533                         lock = nilfs_mdt_bgl_lock(inode, group);
 534                         if (nilfs_palloc_group_desc_nfrees(desc, lock) > 0) {
 535                                 ret = nilfs_palloc_get_bitmap_block(
 536                                         inode, group, 1, &bitmap_bh);
 537                                 if (ret < 0)
 538                                         goto out_desc;
 539                                 bitmap_kaddr = kmap(bitmap_bh->b_page);
 540                                 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
 541                                 pos = nilfs_palloc_find_available_slot(
 542                                         bitmap, group_offset,
 543                                         entries_per_group, lock);
 544                                 if (pos >= 0) {
 545                                         /* found a free entry */
 546                                         nilfs_palloc_group_desc_add_entries(
 547                                                 desc, lock, -1);
 548                                         req->pr_entry_nr =
 549                                                 entries_per_group * group + pos;
 550                                         kunmap(desc_bh->b_page);
 551                                         kunmap(bitmap_bh->b_page);
 552
 553                                         req->pr_desc_bh = desc_bh;
 554                                         req->pr_bitmap_bh = bitmap_bh;
 555                                         return 0;
 556                                 }
 557                                 kunmap(bitmap_bh->b_page);
 558                                 brelse(bitmap_bh);
 559                         }
 560
 561                         group_offset = 0;
 562                 }
 563
 564                 kunmap(desc_bh->b_page);
 565                 brelse(desc_bh);
 566         }
 567
 568         /* no entries left */
 569         return -ENOSPC;
 570
 571  out_desc:
 572         kunmap(desc_bh->b_page);
 573         brelse(desc_bh);
 574         return ret;
 575 }
 576
 577 /**
 578  * nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
 579  * @inode: inode of metadata file using this allocator
 580  * @req: nilfs_palloc_req structure exchanged for the allocation
 581  */
 582 void nilfs_palloc_commit_alloc_entry(struct inode *inode,
 583                                      struct nilfs_palloc_req *req)
 584 {
 585         mark_buffer_dirty(req->pr_bitmap_bh);
 586         mark_buffer_dirty(req->pr_desc_bh);
 587         nilfs_mdt_mark_dirty(inode);
 588
 589         brelse(req->pr_bitmap_bh);
 590         brelse(req->pr_desc_bh);
 591 }
 592
 593 /**
 594  * nilfs_palloc_commit_free_entry - finish deallocating a persistent object
 595  * @inode: inode of metadata file using this allocator
 596  * @req: nilfs_palloc_req structure exchanged for the removal
 597  */
 598 void nilfs_palloc_commit_free_entry(struct inode *inode,
 599                                     struct nilfs_palloc_req *req)
 600 {
 601         struct nilfs_palloc_group_desc *desc;
 602         unsigned long group, group_offset;
 603         unsigned char *bitmap;
 604         void *desc_kaddr, *bitmap_kaddr;
 605         spinlock_t *lock;
 606
 607         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 608         desc_kaddr = kmap(req->pr_desc_bh->b_page);
 609         desc = nilfs_palloc_block_get_group_desc(inode, group,
 610                                                  req->pr_desc_bh, desc_kaddr);
 611         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 612         bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
 613         lock = nilfs_mdt_bgl_lock(inode, group);
 614
 615         if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
 616                 nilfs_msg(inode->i_sb, KERN_WARNING,
 617                           "%s (ino=%lu): entry number %llu already freed",
 618                           __func__, inode->i_ino,
 619                           (unsigned long long)req->pr_entry_nr);
 620         else
 621                 nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 622
 623         kunmap(req->pr_bitmap_bh->b_page);
 624         kunmap(req->pr_desc_bh->b_page);
 625
 626         mark_buffer_dirty(req->pr_desc_bh);
 627         mark_buffer_dirty(req->pr_bitmap_bh);
 628         nilfs_mdt_mark_dirty(inode);
 629
 630         brelse(req->pr_bitmap_bh);
 631         brelse(req->pr_desc_bh);
 632 }
 633
 634 /**
 635  * nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
 636  * @inode: inode of metadata file using this allocator
 637  * @req: nilfs_palloc_req structure exchanged for the allocation
 638  */
 639 void nilfs_palloc_abort_alloc_entry(struct inode *inode,
 640                                     struct nilfs_palloc_req *req)
 641 {
 642         struct nilfs_palloc_group_desc *desc;
 643         void *desc_kaddr, *bitmap_kaddr;
 644         unsigned char *bitmap;
 645         unsigned long group, group_offset;
 646         spinlock_t *lock;
 647
 648         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 649         desc_kaddr = kmap(req->pr_desc_bh->b_page);
 650         desc = nilfs_palloc_block_get_group_desc(inode, group,
 651                                                  req->pr_desc_bh, desc_kaddr);
 652         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 653         bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
 654         lock = nilfs_mdt_bgl_lock(inode, group);
 655
 656         if (!nilfs_clear_bit_atomic(lock, group_offset, bitmap))
 657                 nilfs_msg(inode->i_sb, KERN_WARNING,
 658                           "%s (ino=%lu): entry number %llu already freed",
 659                           __func__, inode->i_ino,
 660                           (unsigned long long)req->pr_entry_nr);
 661         else
 662                 nilfs_palloc_group_desc_add_entries(desc, lock, 1);
 663
 664         kunmap(req->pr_bitmap_bh->b_page);
 665         kunmap(req->pr_desc_bh->b_page);
 666
 667         brelse(req->pr_bitmap_bh);
 668         brelse(req->pr_desc_bh);
 669
 670         req->pr_entry_nr = 0;
 671         req->pr_bitmap_bh = NULL;
 672         req->pr_desc_bh = NULL;
 673 }
 674
 675 /**
 676  * nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
 677  * @inode: inode of metadata file using this allocator
 678  * @req: nilfs_palloc_req structure exchanged for the removal
 679  */
 680 int nilfs_palloc_prepare_free_entry(struct inode *inode,
 681                                     struct nilfs_palloc_req *req)
 682 {
 683         struct buffer_head *desc_bh, *bitmap_bh;
 684         unsigned long group, group_offset;
 685         int ret;
 686
 687         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 688         ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
 689         if (ret < 0)
 690                 return ret;
 691         ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
 692         if (ret < 0) {
 693                 brelse(desc_bh);
 694                 return ret;
 695         }
 696
 697         req->pr_desc_bh = desc_bh;
 698         req->pr_bitmap_bh = bitmap_bh;
 699         return 0;
 700 }
 701
 702 /**
 703  * nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
 704  * @inode: inode of metadata file using this allocator
 705  * @req: nilfs_palloc_req structure exchanged for the removal
 706  */
 707 void nilfs_palloc_abort_free_entry(struct inode *inode,
 708                                    struct nilfs_palloc_req *req)
 709 {
 710         brelse(req->pr_bitmap_bh);
 711         brelse(req->pr_desc_bh);
 712
 713         req->pr_entry_nr = 0;
 714         req->pr_bitmap_bh = NULL;
 715         req->pr_desc_bh = NULL;
 716 }
 717
 718 /**
 719  * nilfs_palloc_freev - deallocate a set of persistent objects
 720  * @inode: inode of metadata file using this allocator
 721  * @entry_nrs: array of entry numbers to be deallocated
 722  * @nitems: number of entries stored in @entry_nrs
 723  */
 724 int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
 725 {
 726         struct buffer_head *desc_bh, *bitmap_bh;
 727         struct nilfs_palloc_group_desc *desc;
 728         unsigned char *bitmap;
 729         void *desc_kaddr, *bitmap_kaddr;
 730         unsigned long group, group_offset;
 731         __u64 group_min_nr, last_nrs[8];
 732         const unsigned long epg = nilfs_palloc_entries_per_group(inode);
 733         const unsigned int epb = NILFS_MDT(inode)->mi_entries_per_block;
 734         unsigned int entry_start, end, pos;
 735         spinlock_t *lock;
 736         int i, j, k, ret;
 737         u32 nfree;
 738
 739         for (i = 0; i < nitems; i = j) {
 740                 int change_group = false;
 741                 int nempties = 0, n = 0;
 742
 743                 group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
 744                 ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
 745                 if (ret < 0)
 746                         return ret;
 747                 ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
 748                                                     &bitmap_bh);
 749                 if (ret < 0) {
 750                         brelse(desc_bh);
 751                         return ret;
 752                 }
 753
 754                 /* Get the first entry number of the group */
 755                 group_min_nr = (__u64)group * epg;
 756
 757                 bitmap_kaddr = kmap(bitmap_bh->b_page);
 758                 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
 759                 lock = nilfs_mdt_bgl_lock(inode, group);
 760
 761                 j = i;
 762                 entry_start = rounddown(group_offset, epb);
 763                 do {
 764                         if (!nilfs_clear_bit_atomic(lock, group_offset,
 765                                                     bitmap)) {
 766                                 nilfs_msg(inode->i_sb, KERN_WARNING,
 767                                           "%s (ino=%lu): entry number %llu already freed",
 768                                           __func__, inode->i_ino,
 769                                           (unsigned long long)entry_nrs[j]);
 770                         } else {
 771                                 n++;
 772                         }
 773
 774                         j++;
 775                         if (j >= nitems || entry_nrs[j] < group_min_nr ||
 776                             entry_nrs[j] >= group_min_nr + epg) {
 777                                 change_group = true;
 778                         } else {
 779                                 group_offset = entry_nrs[j] - group_min_nr;
 780                                 if (group_offset >= entry_start &&
 781                                     group_offset < entry_start + epb) {
 782                                         /* This entry is in the same block */
 783                                         continue;
 784                                 }
 785                         }
 786
 787                         /* Test if the entry block is empty or not */
 788                         end = entry_start + epb;
 789                         pos = nilfs_find_next_bit(bitmap, end, entry_start);
 790                         if (pos >= end) {
 791                                 last_nrs[nempties++] = entry_nrs[j - 1];
 792                                 if (nempties >= ARRAY_SIZE(last_nrs))
 793                                         break;
 794                         }
 795
 796                         if (change_group)
 797                                 break;
 798
 799                         /* Go on to the next entry block */
 800                         entry_start = rounddown(group_offset, epb);
 801                 } while (true);
 802
 803                 kunmap(bitmap_bh->b_page);
 804                 mark_buffer_dirty(bitmap_bh);
 805                 brelse(bitmap_bh);
 806
 807                 for (k = 0; k < nempties; k++) {
 808                         ret = nilfs_palloc_delete_entry_block(inode,
 809                                                               last_nrs[k]);
 810                         if (ret && ret != -ENOENT)
 811                                 nilfs_msg(inode->i_sb, KERN_WARNING,
 812                                           "error %d deleting block that object (entry=%llu, ino=%lu) belongs to",
 813                                           ret, (unsigned long long)last_nrs[k],
 814                                           inode->i_ino);
 815                 }
 816
 817                 desc_kaddr = kmap_atomic(desc_bh->b_page);
 818                 desc = nilfs_palloc_block_get_group_desc(
 819                         inode, group, desc_bh, desc_kaddr);
 820                 nfree = nilfs_palloc_group_desc_add_entries(desc, lock, n);
 821                 kunmap_atomic(desc_kaddr);
 822                 mark_buffer_dirty(desc_bh);
 823                 nilfs_mdt_mark_dirty(inode);
 824                 brelse(desc_bh);
 825
 826                 if (nfree == nilfs_palloc_entries_per_group(inode)) {
 827                         ret = nilfs_palloc_delete_bitmap_block(inode, group);
 828                         if (ret && ret != -ENOENT)
 829                                 nilfs_msg(inode->i_sb, KERN_WARNING,
 830                                           "error %d deleting bitmap block of group=%lu, ino=%lu",
 831                                           ret, group, inode->i_ino);
 832                 }
 833         }
 834         return 0;
 835 }
 836
 837 void nilfs_palloc_setup_cache(struct inode *inode,
 838                               struct nilfs_palloc_cache *cache)
 839 {
 840         NILFS_MDT(inode)->mi_palloc_cache = cache;
 841         spin_lock_init(&cache->lock);
 842 }
 843
 844 void nilfs_palloc_clear_cache(struct inode *inode)
 845 {
 846         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 847
 848         spin_lock(&cache->lock);
 849         brelse(cache->prev_desc.bh);
 850         brelse(cache->prev_bitmap.bh);
 851         brelse(cache->prev_entry.bh);
 852         cache->prev_desc.bh = NULL;
 853         cache->prev_bitmap.bh = NULL;
 854         cache->prev_entry.bh = NULL;
 855         spin_unlock(&cache->lock);
 856 }
 857
 858 void nilfs_palloc_destroy_cache(struct inode *inode)
 859 {
 860         nilfs_palloc_clear_cache(inode);
 861         NILFS_MDT(inode)->mi_palloc_cache = NULL;
 862 }