fs/nilfs2/alloc.c

   1 /*
   2  * alloc.c - NILFS dat/inode allocator
   3  *
   4  * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Original code was written by Koji Sato <koji@osrg.net>.
  21  * Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
  22  *                                Amagai Yoshiji <amagai@osrg.net>.
  23  */
  24
  25 #include <linux/types.h>
  26 #include <linux/buffer_head.h>
  27 #include <linux/fs.h>
  28 #include <linux/bitops.h>
  29 #include <linux/slab.h>
  30 #include "mdt.h"
  31 #include "alloc.h"
  32
  33
  34 /**
  35  * nilfs_palloc_groups_per_desc_block - get the number of groups that a group
  36  *                                      descriptor block can maintain
  37  * @inode: inode of metadata file using this allocator
  38  */
  39 static inline unsigned long
  40 nilfs_palloc_groups_per_desc_block(const struct inode *inode)
  41 {
  42         return (1UL << inode->i_blkbits) /
  43                 sizeof(struct nilfs_palloc_group_desc);
  44 }
  45
  46 /**
  47  * nilfs_palloc_groups_count - get maximum number of groups
  48  * @inode: inode of metadata file using this allocator
  49  */
  50 static inline unsigned long
  51 nilfs_palloc_groups_count(const struct inode *inode)
  52 {
  53         return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
  54 }
  55
  56 /**
  57  * nilfs_palloc_init_blockgroup - initialize private variables for allocator
  58  * @inode: inode of metadata file using this allocator
  59  * @entry_size: size of the persistent object
  60  */
  61 int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned entry_size)
  62 {
  63         struct nilfs_mdt_info *mi = NILFS_MDT(inode);
  64
  65         mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
  66         if (!mi->mi_bgl)
  67                 return -ENOMEM;
  68
  69         bgl_lock_init(mi->mi_bgl);
  70
  71         nilfs_mdt_set_entry_size(inode, entry_size, 0);
  72
  73         mi->mi_blocks_per_group =
  74                 DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
  75                              mi->mi_entries_per_block) + 1;
  76                 /* Number of blocks in a group including entry blocks and
  77                    a bitmap block */
  78         mi->mi_blocks_per_desc_block =
  79                 nilfs_palloc_groups_per_desc_block(inode) *
  80                 mi->mi_blocks_per_group + 1;
  81                 /* Number of blocks per descriptor including the
  82                    descriptor block */
  83         return 0;
  84 }
  85
  86 /**
  87  * nilfs_palloc_group - get group number and offset from an entry number
  88  * @inode: inode of metadata file using this allocator
  89  * @nr: serial number of the entry (e.g. inode number)
  90  * @offset: pointer to store offset number in the group
  91  */
  92 static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
  93                                         unsigned long *offset)
  94 {
  95         __u64 group = nr;
  96
  97         *offset = do_div(group, nilfs_palloc_entries_per_group(inode));
  98         return group;
  99 }
 100
 101 /**
 102  * nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
 103  * @inode: inode of metadata file using this allocator
 104  * @group: group number
 105  *
 106  * nilfs_palloc_desc_blkoff() returns block offset of the descriptor
 107  * block which contains a descriptor of the specified group.
 108  */
 109 static unsigned long
 110 nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
 111 {
 112         unsigned long desc_block =
 113                 group / nilfs_palloc_groups_per_desc_block(inode);
 114         return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
 115 }
 116
 117 /**
 118  * nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
 119  * @inode: inode of metadata file using this allocator
 120  * @group: group number
 121  *
 122  * nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
 123  * block used to allocate/deallocate entries in the specified group.
 124  */
 125 static unsigned long
 126 nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
 127 {
 128         unsigned long desc_offset =
 129                 group % nilfs_palloc_groups_per_desc_block(inode);
 130         return nilfs_palloc_desc_blkoff(inode, group) + 1 +
 131                 desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
 132 }
 133
 134 /**
 135  * nilfs_palloc_group_desc_nfrees - get the number of free entries in a group
 136  * @inode: inode of metadata file using this allocator
 137  * @group: group number
 138  * @desc: pointer to descriptor structure for the group
 139  */
 140 static unsigned long
 141 nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
 142                                const struct nilfs_palloc_group_desc *desc)
 143 {
 144         unsigned long nfree;
 145
 146         spin_lock(nilfs_mdt_bgl_lock(inode, group));
 147         nfree = le32_to_cpu(desc->pg_nfrees);
 148         spin_unlock(nilfs_mdt_bgl_lock(inode, group));
 149         return nfree;
 150 }
 151
 152 /**
 153  * nilfs_palloc_group_desc_add_entries - adjust count of free entries
 154  * @inode: inode of metadata file using this allocator
 155  * @group: group number
 156  * @desc: pointer to descriptor structure for the group
 157  * @n: delta to be added
 158  */
 159 static void
 160 nilfs_palloc_group_desc_add_entries(struct inode *inode,
 161                                     unsigned long group,
 162                                     struct nilfs_palloc_group_desc *desc,
 163                                     u32 n)
 164 {
 165         spin_lock(nilfs_mdt_bgl_lock(inode, group));
 166         le32_add_cpu(&desc->pg_nfrees, n);
 167         spin_unlock(nilfs_mdt_bgl_lock(inode, group));
 168 }
 169
 170 /**
 171  * nilfs_palloc_entry_blkoff - get block offset of an entry block
 172  * @inode: inode of metadata file using this allocator
 173  * @nr: serial number of the entry (e.g. inode number)
 174  */
 175 static unsigned long
 176 nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
 177 {
 178         unsigned long group, group_offset;
 179
 180         group = nilfs_palloc_group(inode, nr, &group_offset);
 181
 182         return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
 183                 group_offset / NILFS_MDT(inode)->mi_entries_per_block;
 184 }
 185
 186 /**
 187  * nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
 188  * @inode: inode of metadata file
 189  * @bh: buffer head of the buffer to be initialized
 190  * @kaddr: kernel address mapped for the page including the buffer
 191  */
 192 static void nilfs_palloc_desc_block_init(struct inode *inode,
 193                                          struct buffer_head *bh, void *kaddr)
 194 {
 195         struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
 196         unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
 197         __le32 nfrees;
 198
 199         nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
 200         while (n-- > 0) {
 201                 desc->pg_nfrees = nfrees;
 202                 desc++;
 203         }
 204 }
 205
 206 static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
 207                                   int create,
 208                                   void (*init_block)(struct inode *,
 209                                                      struct buffer_head *,
 210                                                      void *),
 211                                   struct buffer_head **bhp,
 212                                   struct nilfs_bh_assoc *prev,
 213                                   spinlock_t *lock)
 214 {
 215         int ret;
 216
 217         spin_lock(lock);
 218         if (prev->bh && blkoff == prev->blkoff) {
 219                 get_bh(prev->bh);
 220                 *bhp = prev->bh;
 221                 spin_unlock(lock);
 222                 return 0;
 223         }
 224         spin_unlock(lock);
 225
 226         ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
 227         if (!ret) {
 228                 spin_lock(lock);
 229                 /*
 230                  * The following code must be safe for change of the
 231                  * cache contents during the get block call.
 232                  */
 233                 brelse(prev->bh);
 234                 get_bh(*bhp);
 235                 prev->bh = *bhp;
 236                 prev->blkoff = blkoff;
 237                 spin_unlock(lock);
 238         }
 239         return ret;
 240 }
 241
 242 /**
 243  * nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
 244  * @inode: inode of metadata file using this allocator
 245  * @group: group number
 246  * @create: create flag
 247  * @bhp: pointer to store the resultant buffer head
 248  */
 249 static int nilfs_palloc_get_desc_block(struct inode *inode,
 250                                        unsigned long group,
 251                                        int create, struct buffer_head **bhp)
 252 {
 253         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 254
 255         return nilfs_palloc_get_block(inode,
 256                                       nilfs_palloc_desc_blkoff(inode, group),
 257                                       create, nilfs_palloc_desc_block_init,
 258                                       bhp, &cache->prev_desc, &cache->lock);
 259 }
 260
 261 /**
 262  * nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
 263  * @inode: inode of metadata file using this allocator
 264  * @group: group number
 265  * @create: create flag
 266  * @bhp: pointer to store the resultant buffer head
 267  */
 268 static int nilfs_palloc_get_bitmap_block(struct inode *inode,
 269                                          unsigned long group,
 270                                          int create, struct buffer_head **bhp)
 271 {
 272         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 273
 274         return nilfs_palloc_get_block(inode,
 275                                       nilfs_palloc_bitmap_blkoff(inode, group),
 276                                       create, NULL, bhp,
 277                                       &cache->prev_bitmap, &cache->lock);
 278 }
 279
 280 /**
 281  * nilfs_palloc_get_entry_block - get buffer head of an entry block
 282  * @inode: inode of metadata file using this allocator
 283  * @nr: serial number of the entry (e.g. inode number)
 284  * @create: create flag
 285  * @bhp: pointer to store the resultant buffer head
 286  */
 287 int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
 288                                  int create, struct buffer_head **bhp)
 289 {
 290         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 291
 292         return nilfs_palloc_get_block(inode,
 293                                       nilfs_palloc_entry_blkoff(inode, nr),
 294                                       create, NULL, bhp,
 295                                       &cache->prev_entry, &cache->lock);
 296 }
 297
 298 /**
 299  * nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
 300  * @inode: inode of metadata file using this allocator
 301  * @group: group number
 302  * @bh: buffer head of the buffer storing the group descriptor block
 303  * @kaddr: kernel address mapped for the page including the buffer
 304  */
 305 static struct nilfs_palloc_group_desc *
 306 nilfs_palloc_block_get_group_desc(const struct inode *inode,
 307                                   unsigned long group,
 308                                   const struct buffer_head *bh, void *kaddr)
 309 {
 310         return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
 311                 group % nilfs_palloc_groups_per_desc_block(inode);
 312 }
 313
 314 /**
 315  * nilfs_palloc_block_get_entry - get kernel address of an entry
 316  * @inode: inode of metadata file using this allocator
 317  * @nr: serial number of the entry (e.g. inode number)
 318  * @bh: buffer head of the buffer storing the entry block
 319  * @kaddr: kernel address mapped for the page including the buffer
 320  */
 321 void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
 322                                    const struct buffer_head *bh, void *kaddr)
 323 {
 324         unsigned long entry_offset, group_offset;
 325
 326         nilfs_palloc_group(inode, nr, &group_offset);
 327         entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
 328
 329         return kaddr + bh_offset(bh) +
 330                 entry_offset * NILFS_MDT(inode)->mi_entry_size;
 331 }
 332
 333 /**
 334  * nilfs_palloc_find_available_slot - find available slot in a group
 335  * @inode: inode of metadata file using this allocator
 336  * @group: group number
 337  * @target: offset number of an entry in the group (start point)
 338  * @bitmap: bitmap of the group
 339  * @bsize: size in bits
 340  */
 341 static int nilfs_palloc_find_available_slot(struct inode *inode,
 342                                             unsigned long group,
 343                                             unsigned long target,
 344                                             unsigned char *bitmap,
 345                                             int bsize)
 346 {
 347         int curr, pos, end, i;
 348
 349         if (target > 0) {
 350                 end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
 351                 if (end > bsize)
 352                         end = bsize;
 353                 pos = nilfs_find_next_zero_bit(bitmap, end, target);
 354                 if (pos < end &&
 355                     !nilfs_set_bit_atomic(
 356                             nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
 357                         return pos;
 358         } else
 359                 end = 0;
 360
 361         for (i = 0, curr = end;
 362              i < bsize;
 363              i += BITS_PER_LONG, curr += BITS_PER_LONG) {
 364                 /* wrap around */
 365                 if (curr >= bsize)
 366                         curr = 0;
 367                 while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
 368                        != ~0UL) {
 369                         end = curr + BITS_PER_LONG;
 370                         if (end > bsize)
 371                                 end = bsize;
 372                         pos = nilfs_find_next_zero_bit(bitmap, end, curr);
 373                         if ((pos < end) &&
 374                             !nilfs_set_bit_atomic(
 375                                     nilfs_mdt_bgl_lock(inode, group), pos,
 376                                     bitmap))
 377                                 return pos;
 378                 }
 379         }
 380         return -ENOSPC;
 381 }
 382
 383 /**
 384  * nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
 385  *                                          in a group descriptor block
 386  * @inode: inode of metadata file using this allocator
 387  * @curr: current group number
 388  * @max: maximum number of groups
 389  */
 390 static unsigned long
 391 nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
 392                                        unsigned long curr, unsigned long max)
 393 {
 394         return min_t(unsigned long,
 395                      nilfs_palloc_groups_per_desc_block(inode) -
 396                      curr % nilfs_palloc_groups_per_desc_block(inode),
 397                      max - curr + 1);
 398 }
 399
 400 /**
 401  * nilfs_palloc_count_desc_blocks - count descriptor blocks number
 402  * @inode: inode of metadata file using this allocator
 403  * @desc_blocks: descriptor blocks number [out]
 404  */
 405 static int nilfs_palloc_count_desc_blocks(struct inode *inode,
 406                                             unsigned long *desc_blocks)
 407 {
 408         __u64 blknum;
 409         int ret;
 410
 411         ret = nilfs_bmap_last_key(NILFS_I(inode)->i_bmap, &blknum);
 412         if (likely(!ret))
 413                 *desc_blocks = DIV_ROUND_UP(
 414                         (unsigned long)blknum,
 415                         NILFS_MDT(inode)->mi_blocks_per_desc_block);
 416         return ret;
 417 }
 418
 419 /**
 420  * nilfs_palloc_mdt_file_can_grow - check potential opportunity for
 421  *                                      MDT file growing
 422  * @inode: inode of metadata file using this allocator
 423  * @desc_blocks: known current descriptor blocks count
 424  */
 425 static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
 426                                                     unsigned long desc_blocks)
 427 {
 428         return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
 429                         nilfs_palloc_groups_count(inode);
 430 }
 431
 432 /**
 433  * nilfs_palloc_count_max_entries - count max number of entries that can be
 434  *                                      described by descriptor blocks count
 435  * @inode: inode of metadata file using this allocator
 436  * @nused: current number of used entries
 437  * @nmaxp: max number of entries [out]
 438  */
 439 int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
 440 {
 441         unsigned long desc_blocks = 0;
 442         u64 entries_per_desc_block, nmax;
 443         int err;
 444
 445         err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
 446         if (unlikely(err))
 447                 return err;
 448
 449         entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
 450                                 nilfs_palloc_groups_per_desc_block(inode);
 451         nmax = entries_per_desc_block * desc_blocks;
 452
 453         if (nused == nmax &&
 454                         nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
 455                 nmax += entries_per_desc_block;
 456
 457         if (nused > nmax)
 458                 return -ERANGE;
 459
 460         *nmaxp = nmax;
 461         return 0;
 462 }
 463
 464 /**
 465  * nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
 466  * @inode: inode of metadata file using this allocator
 467  * @req: nilfs_palloc_req structure exchanged for the allocation
 468  */
 469 int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
 470                                      struct nilfs_palloc_req *req)
 471 {
 472         struct buffer_head *desc_bh, *bitmap_bh;
 473         struct nilfs_palloc_group_desc *desc;
 474         unsigned char *bitmap;
 475         void *desc_kaddr, *bitmap_kaddr;
 476         unsigned long group, maxgroup, ngroups;
 477         unsigned long group_offset, maxgroup_offset;
 478         unsigned long n, entries_per_group, groups_per_desc_block;
 479         unsigned long i, j;
 480         int pos, ret;
 481
 482         ngroups = nilfs_palloc_groups_count(inode);
 483         maxgroup = ngroups - 1;
 484         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 485         entries_per_group = nilfs_palloc_entries_per_group(inode);
 486         groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
 487
 488         for (i = 0; i < ngroups; i += n) {
 489                 if (group >= ngroups) {
 490                         /* wrap around */
 491                         group = 0;
 492                         maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
 493                                                       &maxgroup_offset) - 1;
 494                 }
 495                 ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
 496                 if (ret < 0)
 497                         return ret;
 498                 desc_kaddr = kmap(desc_bh->b_page);
 499                 desc = nilfs_palloc_block_get_group_desc(
 500                         inode, group, desc_bh, desc_kaddr);
 501                 n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
 502                                                            maxgroup);
 503                 for (j = 0; j < n; j++, desc++, group++) {
 504                         if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
 505                             > 0) {
 506                                 ret = nilfs_palloc_get_bitmap_block(
 507                                         inode, group, 1, &bitmap_bh);
 508                                 if (ret < 0)
 509                                         goto out_desc;
 510                                 bitmap_kaddr = kmap(bitmap_bh->b_page);
 511                                 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
 512                                 pos = nilfs_palloc_find_available_slot(
 513                                         inode, group, group_offset, bitmap,
 514                                         entries_per_group);
 515                                 if (pos >= 0) {
 516                                         /* found a free entry */
 517                                         nilfs_palloc_group_desc_add_entries(
 518                                                 inode, group, desc, -1);
 519                                         req->pr_entry_nr =
 520                                                 entries_per_group * group + pos;
 521                                         kunmap(desc_bh->b_page);
 522                                         kunmap(bitmap_bh->b_page);
 523
 524                                         req->pr_desc_bh = desc_bh;
 525                                         req->pr_bitmap_bh = bitmap_bh;
 526                                         return 0;
 527                                 }
 528                                 kunmap(bitmap_bh->b_page);
 529                                 brelse(bitmap_bh);
 530                         }
 531
 532                         group_offset = 0;
 533                 }
 534
 535                 kunmap(desc_bh->b_page);
 536                 brelse(desc_bh);
 537         }
 538
 539         /* no entries left */
 540         return -ENOSPC;
 541
 542  out_desc:
 543         kunmap(desc_bh->b_page);
 544         brelse(desc_bh);
 545         return ret;
 546 }
 547
 548 /**
 549  * nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
 550  * @inode: inode of metadata file using this allocator
 551  * @req: nilfs_palloc_req structure exchanged for the allocation
 552  */
 553 void nilfs_palloc_commit_alloc_entry(struct inode *inode,
 554                                      struct nilfs_palloc_req *req)
 555 {
 556         mark_buffer_dirty(req->pr_bitmap_bh);
 557         mark_buffer_dirty(req->pr_desc_bh);
 558         nilfs_mdt_mark_dirty(inode);
 559
 560         brelse(req->pr_bitmap_bh);
 561         brelse(req->pr_desc_bh);
 562 }
 563
 564 /**
 565  * nilfs_palloc_commit_free_entry - finish deallocating a persistent object
 566  * @inode: inode of metadata file using this allocator
 567  * @req: nilfs_palloc_req structure exchanged for the removal
 568  */
 569 void nilfs_palloc_commit_free_entry(struct inode *inode,
 570                                     struct nilfs_palloc_req *req)
 571 {
 572         struct nilfs_palloc_group_desc *desc;
 573         unsigned long group, group_offset;
 574         unsigned char *bitmap;
 575         void *desc_kaddr, *bitmap_kaddr;
 576
 577         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 578         desc_kaddr = kmap(req->pr_desc_bh->b_page);
 579         desc = nilfs_palloc_block_get_group_desc(inode, group,
 580                                                  req->pr_desc_bh, desc_kaddr);
 581         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 582         bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
 583
 584         if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
 585                                     group_offset, bitmap))
 586                 printk(KERN_WARNING "%s: entry number %llu already freed\n",
 587                        __func__, (unsigned long long)req->pr_entry_nr);
 588         else
 589                 nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
 590
 591         kunmap(req->pr_bitmap_bh->b_page);
 592         kunmap(req->pr_desc_bh->b_page);
 593
 594         mark_buffer_dirty(req->pr_desc_bh);
 595         mark_buffer_dirty(req->pr_bitmap_bh);
 596         nilfs_mdt_mark_dirty(inode);
 597
 598         brelse(req->pr_bitmap_bh);
 599         brelse(req->pr_desc_bh);
 600 }
 601
 602 /**
 603  * nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
 604  * @inode: inode of metadata file using this allocator
 605  * @req: nilfs_palloc_req structure exchanged for the allocation
 606  */
 607 void nilfs_palloc_abort_alloc_entry(struct inode *inode,
 608                                     struct nilfs_palloc_req *req)
 609 {
 610         struct nilfs_palloc_group_desc *desc;
 611         void *desc_kaddr, *bitmap_kaddr;
 612         unsigned char *bitmap;
 613         unsigned long group, group_offset;
 614
 615         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 616         desc_kaddr = kmap(req->pr_desc_bh->b_page);
 617         desc = nilfs_palloc_block_get_group_desc(inode, group,
 618                                                  req->pr_desc_bh, desc_kaddr);
 619         bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
 620         bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
 621         if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
 622                                     group_offset, bitmap))
 623                 printk(KERN_WARNING "%s: entry number %llu already freed\n",
 624                        __func__, (unsigned long long)req->pr_entry_nr);
 625         else
 626                 nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
 627
 628         kunmap(req->pr_bitmap_bh->b_page);
 629         kunmap(req->pr_desc_bh->b_page);
 630
 631         brelse(req->pr_bitmap_bh);
 632         brelse(req->pr_desc_bh);
 633
 634         req->pr_entry_nr = 0;
 635         req->pr_bitmap_bh = NULL;
 636         req->pr_desc_bh = NULL;
 637 }
 638
 639 /**
 640  * nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
 641  * @inode: inode of metadata file using this allocator
 642  * @req: nilfs_palloc_req structure exchanged for the removal
 643  */
 644 int nilfs_palloc_prepare_free_entry(struct inode *inode,
 645                                     struct nilfs_palloc_req *req)
 646 {
 647         struct buffer_head *desc_bh, *bitmap_bh;
 648         unsigned long group, group_offset;
 649         int ret;
 650
 651         group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
 652         ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
 653         if (ret < 0)
 654                 return ret;
 655         ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
 656         if (ret < 0) {
 657                 brelse(desc_bh);
 658                 return ret;
 659         }
 660
 661         req->pr_desc_bh = desc_bh;
 662         req->pr_bitmap_bh = bitmap_bh;
 663         return 0;
 664 }
 665
 666 /**
 667  * nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
 668  * @inode: inode of metadata file using this allocator
 669  * @req: nilfs_palloc_req structure exchanged for the removal
 670  */
 671 void nilfs_palloc_abort_free_entry(struct inode *inode,
 672                                    struct nilfs_palloc_req *req)
 673 {
 674         brelse(req->pr_bitmap_bh);
 675         brelse(req->pr_desc_bh);
 676
 677         req->pr_entry_nr = 0;
 678         req->pr_bitmap_bh = NULL;
 679         req->pr_desc_bh = NULL;
 680 }
 681
 682 /**
 683  * nilfs_palloc_group_is_in - judge if an entry is in a group
 684  * @inode: inode of metadata file using this allocator
 685  * @group: group number
 686  * @nr: serial number of the entry (e.g. inode number)
 687  */
 688 static int
 689 nilfs_palloc_group_is_in(struct inode *inode, unsigned long group, __u64 nr)
 690 {
 691         __u64 first, last;
 692
 693         first = group * nilfs_palloc_entries_per_group(inode);
 694         last = first + nilfs_palloc_entries_per_group(inode) - 1;
 695         return (nr >= first) && (nr <= last);
 696 }
 697
 698 /**
 699  * nilfs_palloc_freev - deallocate a set of persistent objects
 700  * @inode: inode of metadata file using this allocator
 701  * @entry_nrs: array of entry numbers to be deallocated
 702  * @nitems: number of entries stored in @entry_nrs
 703  */
 704 int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
 705 {
 706         struct buffer_head *desc_bh, *bitmap_bh;
 707         struct nilfs_palloc_group_desc *desc;
 708         unsigned char *bitmap;
 709         void *desc_kaddr, *bitmap_kaddr;
 710         unsigned long group, group_offset;
 711         int i, j, n, ret;
 712
 713         for (i = 0; i < nitems; i = j) {
 714                 group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
 715                 ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
 716                 if (ret < 0)
 717                         return ret;
 718                 ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
 719                                                     &bitmap_bh);
 720                 if (ret < 0) {
 721                         brelse(desc_bh);
 722                         return ret;
 723                 }
 724                 desc_kaddr = kmap(desc_bh->b_page);
 725                 desc = nilfs_palloc_block_get_group_desc(
 726                         inode, group, desc_bh, desc_kaddr);
 727                 bitmap_kaddr = kmap(bitmap_bh->b_page);
 728                 bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
 729                 for (j = i, n = 0;
 730                      (j < nitems) && nilfs_palloc_group_is_in(inode, group,
 731                                                               entry_nrs[j]);
 732                      j++) {
 733                         nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
 734                         if (!nilfs_clear_bit_atomic(
 735                                     nilfs_mdt_bgl_lock(inode, group),
 736                                     group_offset, bitmap)) {
 737                                 printk(KERN_WARNING
 738                                        "%s: entry number %llu already freed\n",
 739                                        __func__,
 740                                        (unsigned long long)entry_nrs[j]);
 741                         } else {
 742                                 n++;
 743                         }
 744                 }
 745                 nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
 746
 747                 kunmap(bitmap_bh->b_page);
 748                 kunmap(desc_bh->b_page);
 749
 750                 mark_buffer_dirty(desc_bh);
 751                 mark_buffer_dirty(bitmap_bh);
 752                 nilfs_mdt_mark_dirty(inode);
 753
 754                 brelse(bitmap_bh);
 755                 brelse(desc_bh);
 756         }
 757         return 0;
 758 }
 759
 760 void nilfs_palloc_setup_cache(struct inode *inode,
 761                               struct nilfs_palloc_cache *cache)
 762 {
 763         NILFS_MDT(inode)->mi_palloc_cache = cache;
 764         spin_lock_init(&cache->lock);
 765 }
 766
 767 void nilfs_palloc_clear_cache(struct inode *inode)
 768 {
 769         struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
 770
 771         spin_lock(&cache->lock);
 772         brelse(cache->prev_desc.bh);
 773         brelse(cache->prev_bitmap.bh);
 774         brelse(cache->prev_entry.bh);
 775         cache->prev_desc.bh = NULL;
 776         cache->prev_bitmap.bh = NULL;
 777         cache->prev_entry.bh = NULL;
 778         spin_unlock(&cache->lock);
 779 }
 780
 781 void nilfs_palloc_destroy_cache(struct inode *inode)
 782 {
 783         nilfs_palloc_clear_cache(inode);
 784         NILFS_MDT(inode)->mi_palloc_cache = NULL;
 785 }