linux/fs/nilfs2/alloc.c
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   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 */
  25static inline unsigned long
  26nilfs_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 */
  36static inline unsigned long
  37nilfs_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 */
  47int 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 */
  82static 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 */
  99static unsigned long
 100nilfs_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 */
 115static unsigned long
 116nilfs_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 */
 129static unsigned long
 130nilfs_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 */
 147static u32
 148nilfs_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 */
 165static unsigned long
 166nilfs_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 */
 182static 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
 196static 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 */
 239static 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 */
 259static 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 */
 278static 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 */
 295static 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 */
 313int 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 */
 329static 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 */
 345static struct nilfs_palloc_group_desc *
 346nilfs_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 */
 361void *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 */
 380static 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 */
 419static unsigned long
 420nilfs_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 */
 434static 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 */
 454static 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 */
 468int 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 */
 498int 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 */
 582void 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 */
 598void 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 */
 639void 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 */
 680int 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 */
 707void 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 */
 724int 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
 837void 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
 844void 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
 858void nilfs_palloc_destroy_cache(struct inode *inode)
 859{
 860        nilfs_palloc_clear_cache(inode);
 861        NILFS_MDT(inode)->mi_palloc_cache = NULL;
 862}
 863