linux/fs/jfs/jfs_dmap.c
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   1/*
   2 *   Copyright (C) International Business Machines Corp., 2000-2004
   3 *   Portions Copyright (C) Tino Reichardt, 2012
   4 *
   5 *   This program is free software;  you can redistribute it and/or modify
   6 *   it under the terms of the GNU General Public License as published by
   7 *   the Free Software Foundation; either version 2 of the License, or
   8 *   (at your option) any later version.
   9 *
  10 *   This program is distributed in the hope that it will be useful,
  11 *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
  12 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  13 *   the GNU General Public License for more details.
  14 *
  15 *   You should have received a copy of the GNU General Public License
  16 *   along with this program;  if not, write to the Free Software
  17 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18 */
  19
  20#include <linux/fs.h>
  21#include <linux/slab.h>
  22#include "jfs_incore.h"
  23#include "jfs_superblock.h"
  24#include "jfs_dmap.h"
  25#include "jfs_imap.h"
  26#include "jfs_lock.h"
  27#include "jfs_metapage.h"
  28#include "jfs_debug.h"
  29#include "jfs_discard.h"
  30
  31/*
  32 *      SERIALIZATION of the Block Allocation Map.
  33 *
  34 *      the working state of the block allocation map is accessed in
  35 *      two directions:
  36 *
  37 *      1) allocation and free requests that start at the dmap
  38 *         level and move up through the dmap control pages (i.e.
  39 *         the vast majority of requests).
  40 *
  41 *      2) allocation requests that start at dmap control page
  42 *         level and work down towards the dmaps.
  43 *
  44 *      the serialization scheme used here is as follows.
  45 *
  46 *      requests which start at the bottom are serialized against each
  47 *      other through buffers and each requests holds onto its buffers
  48 *      as it works it way up from a single dmap to the required level
  49 *      of dmap control page.
  50 *      requests that start at the top are serialized against each other
  51 *      and request that start from the bottom by the multiple read/single
  52 *      write inode lock of the bmap inode. requests starting at the top
  53 *      take this lock in write mode while request starting at the bottom
  54 *      take the lock in read mode.  a single top-down request may proceed
  55 *      exclusively while multiple bottoms-up requests may proceed
  56 *      simultaneously (under the protection of busy buffers).
  57 *
  58 *      in addition to information found in dmaps and dmap control pages,
  59 *      the working state of the block allocation map also includes read/
  60 *      write information maintained in the bmap descriptor (i.e. total
  61 *      free block count, allocation group level free block counts).
  62 *      a single exclusive lock (BMAP_LOCK) is used to guard this information
  63 *      in the face of multiple-bottoms up requests.
  64 *      (lock ordering: IREAD_LOCK, BMAP_LOCK);
  65 *
  66 *      accesses to the persistent state of the block allocation map (limited
  67 *      to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
  68 */
  69
  70#define BMAP_LOCK_INIT(bmp)     mutex_init(&bmp->db_bmaplock)
  71#define BMAP_LOCK(bmp)          mutex_lock(&bmp->db_bmaplock)
  72#define BMAP_UNLOCK(bmp)        mutex_unlock(&bmp->db_bmaplock)
  73
  74/*
  75 * forward references
  76 */
  77static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
  78                        int nblocks);
  79static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
  80static int dbBackSplit(dmtree_t * tp, int leafno);
  81static int dbJoin(dmtree_t * tp, int leafno, int newval);
  82static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
  83static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
  84                    int level);
  85static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
  86static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
  87                       int nblocks);
  88static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
  89                       int nblocks,
  90                       int l2nb, s64 * results);
  91static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
  92                       int nblocks);
  93static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
  94                          int l2nb,
  95                          s64 * results);
  96static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
  97                     s64 * results);
  98static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
  99                      s64 * results);
 100static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
 101static int dbFindBits(u32 word, int l2nb);
 102static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
 103static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
 104static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
 105                      int nblocks);
 106static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
 107                      int nblocks);
 108static int dbMaxBud(u8 * cp);
 109static int blkstol2(s64 nb);
 110
 111static int cntlz(u32 value);
 112static int cnttz(u32 word);
 113
 114static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
 115                         int nblocks);
 116static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
 117static int dbInitDmapTree(struct dmap * dp);
 118static int dbInitTree(struct dmaptree * dtp);
 119static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
 120static int dbGetL2AGSize(s64 nblocks);
 121
 122/*
 123 *      buddy table
 124 *
 125 * table used for determining buddy sizes within characters of
 126 * dmap bitmap words.  the characters themselves serve as indexes
 127 * into the table, with the table elements yielding the maximum
 128 * binary buddy of free bits within the character.
 129 */
 130static const s8 budtab[256] = {
 131        3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
 132        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 133        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 134        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 135        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 136        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 137        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 138        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 139        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 140        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 141        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 142        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 143        2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 144        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 145        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
 146        2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
 147};
 148
 149/*
 150 * NAME:        dbMount()
 151 *
 152 * FUNCTION:    initializate the block allocation map.
 153 *
 154 *              memory is allocated for the in-core bmap descriptor and
 155 *              the in-core descriptor is initialized from disk.
 156 *
 157 * PARAMETERS:
 158 *      ipbmap  - pointer to in-core inode for the block map.
 159 *
 160 * RETURN VALUES:
 161 *      0       - success
 162 *      -ENOMEM - insufficient memory
 163 *      -EIO    - i/o error
 164 */
 165int dbMount(struct inode *ipbmap)
 166{
 167        struct bmap *bmp;
 168        struct dbmap_disk *dbmp_le;
 169        struct metapage *mp;
 170        int i;
 171
 172        /*
 173         * allocate/initialize the in-memory bmap descriptor
 174         */
 175        /* allocate memory for the in-memory bmap descriptor */
 176        bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
 177        if (bmp == NULL)
 178                return -ENOMEM;
 179
 180        /* read the on-disk bmap descriptor. */
 181        mp = read_metapage(ipbmap,
 182                           BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
 183                           PSIZE, 0);
 184        if (mp == NULL) {
 185                kfree(bmp);
 186                return -EIO;
 187        }
 188
 189        /* copy the on-disk bmap descriptor to its in-memory version. */
 190        dbmp_le = (struct dbmap_disk *) mp->data;
 191        bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
 192        bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
 193        bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
 194        bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
 195        bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
 196        bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
 197        bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
 198        bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
 199        bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
 200        bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
 201        bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
 202        bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
 203        for (i = 0; i < MAXAG; i++)
 204                bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
 205        bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
 206        bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
 207
 208        /* release the buffer. */
 209        release_metapage(mp);
 210
 211        /* bind the bmap inode and the bmap descriptor to each other. */
 212        bmp->db_ipbmap = ipbmap;
 213        JFS_SBI(ipbmap->i_sb)->bmap = bmp;
 214
 215        memset(bmp->db_active, 0, sizeof(bmp->db_active));
 216
 217        /*
 218         * allocate/initialize the bmap lock
 219         */
 220        BMAP_LOCK_INIT(bmp);
 221
 222        return (0);
 223}
 224
 225
 226/*
 227 * NAME:        dbUnmount()
 228 *
 229 * FUNCTION:    terminate the block allocation map in preparation for
 230 *              file system unmount.
 231 *
 232 *              the in-core bmap descriptor is written to disk and
 233 *              the memory for this descriptor is freed.
 234 *
 235 * PARAMETERS:
 236 *      ipbmap  - pointer to in-core inode for the block map.
 237 *
 238 * RETURN VALUES:
 239 *      0       - success
 240 *      -EIO    - i/o error
 241 */
 242int dbUnmount(struct inode *ipbmap, int mounterror)
 243{
 244        struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
 245
 246        if (!(mounterror || isReadOnly(ipbmap)))
 247                dbSync(ipbmap);
 248
 249        /*
 250         * Invalidate the page cache buffers
 251         */
 252        truncate_inode_pages(ipbmap->i_mapping, 0);
 253
 254        /* free the memory for the in-memory bmap. */
 255        kfree(bmp);
 256
 257        return (0);
 258}
 259
 260/*
 261 *      dbSync()
 262 */
 263int dbSync(struct inode *ipbmap)
 264{
 265        struct dbmap_disk *dbmp_le;
 266        struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
 267        struct metapage *mp;
 268        int i;
 269
 270        /*
 271         * write bmap global control page
 272         */
 273        /* get the buffer for the on-disk bmap descriptor. */
 274        mp = read_metapage(ipbmap,
 275                           BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
 276                           PSIZE, 0);
 277        if (mp == NULL) {
 278                jfs_err("dbSync: read_metapage failed!");
 279                return -EIO;
 280        }
 281        /* copy the in-memory version of the bmap to the on-disk version */
 282        dbmp_le = (struct dbmap_disk *) mp->data;
 283        dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
 284        dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
 285        dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
 286        dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
 287        dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
 288        dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
 289        dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
 290        dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
 291        dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
 292        dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
 293        dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
 294        dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
 295        for (i = 0; i < MAXAG; i++)
 296                dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
 297        dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
 298        dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
 299
 300        /* write the buffer */
 301        write_metapage(mp);
 302
 303        /*
 304         * write out dirty pages of bmap
 305         */
 306        filemap_write_and_wait(ipbmap->i_mapping);
 307
 308        diWriteSpecial(ipbmap, 0);
 309
 310        return (0);
 311}
 312
 313/*
 314 * NAME:        dbFree()
 315 *
 316 * FUNCTION:    free the specified block range from the working block
 317 *              allocation map.
 318 *
 319 *              the blocks will be free from the working map one dmap
 320 *              at a time.
 321 *
 322 * PARAMETERS:
 323 *      ip      - pointer to in-core inode;
 324 *      blkno   - starting block number to be freed.
 325 *      nblocks - number of blocks to be freed.
 326 *
 327 * RETURN VALUES:
 328 *      0       - success
 329 *      -EIO    - i/o error
 330 */
 331int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
 332{
 333        struct metapage *mp;
 334        struct dmap *dp;
 335        int nb, rc;
 336        s64 lblkno, rem;
 337        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
 338        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
 339        struct super_block *sb = ipbmap->i_sb;
 340
 341        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 342
 343        /* block to be freed better be within the mapsize. */
 344        if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
 345                IREAD_UNLOCK(ipbmap);
 346                printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
 347                       (unsigned long long) blkno,
 348                       (unsigned long long) nblocks);
 349                jfs_error(ip->i_sb,
 350                          "dbFree: block to be freed is outside the map");
 351                return -EIO;
 352        }
 353
 354        /**
 355         * TRIM the blocks, when mounted with discard option
 356         */
 357        if (JFS_SBI(sb)->flag & JFS_DISCARD)
 358                if (JFS_SBI(sb)->minblks_trim <= nblocks)
 359                        jfs_issue_discard(ipbmap, blkno, nblocks);
 360
 361        /*
 362         * free the blocks a dmap at a time.
 363         */
 364        mp = NULL;
 365        for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
 366                /* release previous dmap if any */
 367                if (mp) {
 368                        write_metapage(mp);
 369                }
 370
 371                /* get the buffer for the current dmap. */
 372                lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
 373                mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
 374                if (mp == NULL) {
 375                        IREAD_UNLOCK(ipbmap);
 376                        return -EIO;
 377                }
 378                dp = (struct dmap *) mp->data;
 379
 380                /* determine the number of blocks to be freed from
 381                 * this dmap.
 382                 */
 383                nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
 384
 385                /* free the blocks. */
 386                if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
 387                        jfs_error(ip->i_sb, "dbFree: error in block map\n");
 388                        release_metapage(mp);
 389                        IREAD_UNLOCK(ipbmap);
 390                        return (rc);
 391                }
 392        }
 393
 394        /* write the last buffer. */
 395        write_metapage(mp);
 396
 397        IREAD_UNLOCK(ipbmap);
 398
 399        return (0);
 400}
 401
 402
 403/*
 404 * NAME:        dbUpdatePMap()
 405 *
 406 * FUNCTION:    update the allocation state (free or allocate) of the
 407 *              specified block range in the persistent block allocation map.
 408 *
 409 *              the blocks will be updated in the persistent map one
 410 *              dmap at a time.
 411 *
 412 * PARAMETERS:
 413 *      ipbmap  - pointer to in-core inode for the block map.
 414 *      free    - 'true' if block range is to be freed from the persistent
 415 *                map; 'false' if it is to be allocated.
 416 *      blkno   - starting block number of the range.
 417 *      nblocks - number of contiguous blocks in the range.
 418 *      tblk    - transaction block;
 419 *
 420 * RETURN VALUES:
 421 *      0       - success
 422 *      -EIO    - i/o error
 423 */
 424int
 425dbUpdatePMap(struct inode *ipbmap,
 426             int free, s64 blkno, s64 nblocks, struct tblock * tblk)
 427{
 428        int nblks, dbitno, wbitno, rbits;
 429        int word, nbits, nwords;
 430        struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
 431        s64 lblkno, rem, lastlblkno;
 432        u32 mask;
 433        struct dmap *dp;
 434        struct metapage *mp;
 435        struct jfs_log *log;
 436        int lsn, difft, diffp;
 437        unsigned long flags;
 438
 439        /* the blocks better be within the mapsize. */
 440        if (blkno + nblocks > bmp->db_mapsize) {
 441                printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
 442                       (unsigned long long) blkno,
 443                       (unsigned long long) nblocks);
 444                jfs_error(ipbmap->i_sb,
 445                          "dbUpdatePMap: blocks are outside the map");
 446                return -EIO;
 447        }
 448
 449        /* compute delta of transaction lsn from log syncpt */
 450        lsn = tblk->lsn;
 451        log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
 452        logdiff(difft, lsn, log);
 453
 454        /*
 455         * update the block state a dmap at a time.
 456         */
 457        mp = NULL;
 458        lastlblkno = 0;
 459        for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
 460                /* get the buffer for the current dmap. */
 461                lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
 462                if (lblkno != lastlblkno) {
 463                        if (mp) {
 464                                write_metapage(mp);
 465                        }
 466
 467                        mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
 468                                           0);
 469                        if (mp == NULL)
 470                                return -EIO;
 471                        metapage_wait_for_io(mp);
 472                }
 473                dp = (struct dmap *) mp->data;
 474
 475                /* determine the bit number and word within the dmap of
 476                 * the starting block.  also determine how many blocks
 477                 * are to be updated within this dmap.
 478                 */
 479                dbitno = blkno & (BPERDMAP - 1);
 480                word = dbitno >> L2DBWORD;
 481                nblks = min(rem, (s64)BPERDMAP - dbitno);
 482
 483                /* update the bits of the dmap words. the first and last
 484                 * words may only have a subset of their bits updated. if
 485                 * this is the case, we'll work against that word (i.e.
 486                 * partial first and/or last) only in a single pass.  a
 487                 * single pass will also be used to update all words that
 488                 * are to have all their bits updated.
 489                 */
 490                for (rbits = nblks; rbits > 0;
 491                     rbits -= nbits, dbitno += nbits) {
 492                        /* determine the bit number within the word and
 493                         * the number of bits within the word.
 494                         */
 495                        wbitno = dbitno & (DBWORD - 1);
 496                        nbits = min(rbits, DBWORD - wbitno);
 497
 498                        /* check if only part of the word is to be updated. */
 499                        if (nbits < DBWORD) {
 500                                /* update (free or allocate) the bits
 501                                 * in this word.
 502                                 */
 503                                mask =
 504                                    (ONES << (DBWORD - nbits) >> wbitno);
 505                                if (free)
 506                                        dp->pmap[word] &=
 507                                            cpu_to_le32(~mask);
 508                                else
 509                                        dp->pmap[word] |=
 510                                            cpu_to_le32(mask);
 511
 512                                word += 1;
 513                        } else {
 514                                /* one or more words are to have all
 515                                 * their bits updated.  determine how
 516                                 * many words and how many bits.
 517                                 */
 518                                nwords = rbits >> L2DBWORD;
 519                                nbits = nwords << L2DBWORD;
 520
 521                                /* update (free or allocate) the bits
 522                                 * in these words.
 523                                 */
 524                                if (free)
 525                                        memset(&dp->pmap[word], 0,
 526                                               nwords * 4);
 527                                else
 528                                        memset(&dp->pmap[word], (int) ONES,
 529                                               nwords * 4);
 530
 531                                word += nwords;
 532                        }
 533                }
 534
 535                /*
 536                 * update dmap lsn
 537                 */
 538                if (lblkno == lastlblkno)
 539                        continue;
 540
 541                lastlblkno = lblkno;
 542
 543                LOGSYNC_LOCK(log, flags);
 544                if (mp->lsn != 0) {
 545                        /* inherit older/smaller lsn */
 546                        logdiff(diffp, mp->lsn, log);
 547                        if (difft < diffp) {
 548                                mp->lsn = lsn;
 549
 550                                /* move bp after tblock in logsync list */
 551                                list_move(&mp->synclist, &tblk->synclist);
 552                        }
 553
 554                        /* inherit younger/larger clsn */
 555                        logdiff(difft, tblk->clsn, log);
 556                        logdiff(diffp, mp->clsn, log);
 557                        if (difft > diffp)
 558                                mp->clsn = tblk->clsn;
 559                } else {
 560                        mp->log = log;
 561                        mp->lsn = lsn;
 562
 563                        /* insert bp after tblock in logsync list */
 564                        log->count++;
 565                        list_add(&mp->synclist, &tblk->synclist);
 566
 567                        mp->clsn = tblk->clsn;
 568                }
 569                LOGSYNC_UNLOCK(log, flags);
 570        }
 571
 572        /* write the last buffer. */
 573        if (mp) {
 574                write_metapage(mp);
 575        }
 576
 577        return (0);
 578}
 579
 580
 581/*
 582 * NAME:        dbNextAG()
 583 *
 584 * FUNCTION:    find the preferred allocation group for new allocations.
 585 *
 586 *              Within the allocation groups, we maintain a preferred
 587 *              allocation group which consists of a group with at least
 588 *              average free space.  It is the preferred group that we target
 589 *              new inode allocation towards.  The tie-in between inode
 590 *              allocation and block allocation occurs as we allocate the
 591 *              first (data) block of an inode and specify the inode (block)
 592 *              as the allocation hint for this block.
 593 *
 594 *              We try to avoid having more than one open file growing in
 595 *              an allocation group, as this will lead to fragmentation.
 596 *              This differs from the old OS/2 method of trying to keep
 597 *              empty ags around for large allocations.
 598 *
 599 * PARAMETERS:
 600 *      ipbmap  - pointer to in-core inode for the block map.
 601 *
 602 * RETURN VALUES:
 603 *      the preferred allocation group number.
 604 */
 605int dbNextAG(struct inode *ipbmap)
 606{
 607        s64 avgfree;
 608        int agpref;
 609        s64 hwm = 0;
 610        int i;
 611        int next_best = -1;
 612        struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
 613
 614        BMAP_LOCK(bmp);
 615
 616        /* determine the average number of free blocks within the ags. */
 617        avgfree = (u32)bmp->db_nfree / bmp->db_numag;
 618
 619        /*
 620         * if the current preferred ag does not have an active allocator
 621         * and has at least average freespace, return it
 622         */
 623        agpref = bmp->db_agpref;
 624        if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
 625            (bmp->db_agfree[agpref] >= avgfree))
 626                goto unlock;
 627
 628        /* From the last preferred ag, find the next one with at least
 629         * average free space.
 630         */
 631        for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
 632                if (agpref == bmp->db_numag)
 633                        agpref = 0;
 634
 635                if (atomic_read(&bmp->db_active[agpref]))
 636                        /* open file is currently growing in this ag */
 637                        continue;
 638                if (bmp->db_agfree[agpref] >= avgfree) {
 639                        /* Return this one */
 640                        bmp->db_agpref = agpref;
 641                        goto unlock;
 642                } else if (bmp->db_agfree[agpref] > hwm) {
 643                        /* Less than avg. freespace, but best so far */
 644                        hwm = bmp->db_agfree[agpref];
 645                        next_best = agpref;
 646                }
 647        }
 648
 649        /*
 650         * If no inactive ag was found with average freespace, use the
 651         * next best
 652         */
 653        if (next_best != -1)
 654                bmp->db_agpref = next_best;
 655        /* else leave db_agpref unchanged */
 656unlock:
 657        BMAP_UNLOCK(bmp);
 658
 659        /* return the preferred group.
 660         */
 661        return (bmp->db_agpref);
 662}
 663
 664/*
 665 * NAME:        dbAlloc()
 666 *
 667 * FUNCTION:    attempt to allocate a specified number of contiguous free
 668 *              blocks from the working allocation block map.
 669 *
 670 *              the block allocation policy uses hints and a multi-step
 671 *              approach.
 672 *
 673 *              for allocation requests smaller than the number of blocks
 674 *              per dmap, we first try to allocate the new blocks
 675 *              immediately following the hint.  if these blocks are not
 676 *              available, we try to allocate blocks near the hint.  if
 677 *              no blocks near the hint are available, we next try to
 678 *              allocate within the same dmap as contains the hint.
 679 *
 680 *              if no blocks are available in the dmap or the allocation
 681 *              request is larger than the dmap size, we try to allocate
 682 *              within the same allocation group as contains the hint. if
 683 *              this does not succeed, we finally try to allocate anywhere
 684 *              within the aggregate.
 685 *
 686 *              we also try to allocate anywhere within the aggregate for
 687 *              for allocation requests larger than the allocation group
 688 *              size or requests that specify no hint value.
 689 *
 690 * PARAMETERS:
 691 *      ip      - pointer to in-core inode;
 692 *      hint    - allocation hint.
 693 *      nblocks - number of contiguous blocks in the range.
 694 *      results - on successful return, set to the starting block number
 695 *                of the newly allocated contiguous range.
 696 *
 697 * RETURN VALUES:
 698 *      0       - success
 699 *      -ENOSPC - insufficient disk resources
 700 *      -EIO    - i/o error
 701 */
 702int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
 703{
 704        int rc, agno;
 705        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
 706        struct bmap *bmp;
 707        struct metapage *mp;
 708        s64 lblkno, blkno;
 709        struct dmap *dp;
 710        int l2nb;
 711        s64 mapSize;
 712        int writers;
 713
 714        /* assert that nblocks is valid */
 715        assert(nblocks > 0);
 716
 717        /* get the log2 number of blocks to be allocated.
 718         * if the number of blocks is not a log2 multiple,
 719         * it will be rounded up to the next log2 multiple.
 720         */
 721        l2nb = BLKSTOL2(nblocks);
 722
 723        bmp = JFS_SBI(ip->i_sb)->bmap;
 724
 725        mapSize = bmp->db_mapsize;
 726
 727        /* the hint should be within the map */
 728        if (hint >= mapSize) {
 729                jfs_error(ip->i_sb, "dbAlloc: the hint is outside the map");
 730                return -EIO;
 731        }
 732
 733        /* if the number of blocks to be allocated is greater than the
 734         * allocation group size, try to allocate anywhere.
 735         */
 736        if (l2nb > bmp->db_agl2size) {
 737                IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 738
 739                rc = dbAllocAny(bmp, nblocks, l2nb, results);
 740
 741                goto write_unlock;
 742        }
 743
 744        /*
 745         * If no hint, let dbNextAG recommend an allocation group
 746         */
 747        if (hint == 0)
 748                goto pref_ag;
 749
 750        /* we would like to allocate close to the hint.  adjust the
 751         * hint to the block following the hint since the allocators
 752         * will start looking for free space starting at this point.
 753         */
 754        blkno = hint + 1;
 755
 756        if (blkno >= bmp->db_mapsize)
 757                goto pref_ag;
 758
 759        agno = blkno >> bmp->db_agl2size;
 760
 761        /* check if blkno crosses over into a new allocation group.
 762         * if so, check if we should allow allocations within this
 763         * allocation group.
 764         */
 765        if ((blkno & (bmp->db_agsize - 1)) == 0)
 766                /* check if the AG is currently being written to.
 767                 * if so, call dbNextAG() to find a non-busy
 768                 * AG with sufficient free space.
 769                 */
 770                if (atomic_read(&bmp->db_active[agno]))
 771                        goto pref_ag;
 772
 773        /* check if the allocation request size can be satisfied from a
 774         * single dmap.  if so, try to allocate from the dmap containing
 775         * the hint using a tiered strategy.
 776         */
 777        if (nblocks <= BPERDMAP) {
 778                IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 779
 780                /* get the buffer for the dmap containing the hint.
 781                 */
 782                rc = -EIO;
 783                lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
 784                mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
 785                if (mp == NULL)
 786                        goto read_unlock;
 787
 788                dp = (struct dmap *) mp->data;
 789
 790                /* first, try to satisfy the allocation request with the
 791                 * blocks beginning at the hint.
 792                 */
 793                if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
 794                    != -ENOSPC) {
 795                        if (rc == 0) {
 796                                *results = blkno;
 797                                mark_metapage_dirty(mp);
 798                        }
 799
 800                        release_metapage(mp);
 801                        goto read_unlock;
 802                }
 803
 804                writers = atomic_read(&bmp->db_active[agno]);
 805                if ((writers > 1) ||
 806                    ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
 807                        /*
 808                         * Someone else is writing in this allocation
 809                         * group.  To avoid fragmenting, try another ag
 810                         */
 811                        release_metapage(mp);
 812                        IREAD_UNLOCK(ipbmap);
 813                        goto pref_ag;
 814                }
 815
 816                /* next, try to satisfy the allocation request with blocks
 817                 * near the hint.
 818                 */
 819                if ((rc =
 820                     dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
 821                    != -ENOSPC) {
 822                        if (rc == 0)
 823                                mark_metapage_dirty(mp);
 824
 825                        release_metapage(mp);
 826                        goto read_unlock;
 827                }
 828
 829                /* try to satisfy the allocation request with blocks within
 830                 * the same dmap as the hint.
 831                 */
 832                if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
 833                    != -ENOSPC) {
 834                        if (rc == 0)
 835                                mark_metapage_dirty(mp);
 836
 837                        release_metapage(mp);
 838                        goto read_unlock;
 839                }
 840
 841                release_metapage(mp);
 842                IREAD_UNLOCK(ipbmap);
 843        }
 844
 845        /* try to satisfy the allocation request with blocks within
 846         * the same allocation group as the hint.
 847         */
 848        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 849        if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
 850                goto write_unlock;
 851
 852        IWRITE_UNLOCK(ipbmap);
 853
 854
 855      pref_ag:
 856        /*
 857         * Let dbNextAG recommend a preferred allocation group
 858         */
 859        agno = dbNextAG(ipbmap);
 860        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
 861
 862        /* Try to allocate within this allocation group.  if that fails, try to
 863         * allocate anywhere in the map.
 864         */
 865        if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
 866                rc = dbAllocAny(bmp, nblocks, l2nb, results);
 867
 868      write_unlock:
 869        IWRITE_UNLOCK(ipbmap);
 870
 871        return (rc);
 872
 873      read_unlock:
 874        IREAD_UNLOCK(ipbmap);
 875
 876        return (rc);
 877}
 878
 879#ifdef _NOTYET
 880/*
 881 * NAME:        dbAllocExact()
 882 *
 883 * FUNCTION:    try to allocate the requested extent;
 884 *
 885 * PARAMETERS:
 886 *      ip      - pointer to in-core inode;
 887 *      blkno   - extent address;
 888 *      nblocks - extent length;
 889 *
 890 * RETURN VALUES:
 891 *      0       - success
 892 *      -ENOSPC - insufficient disk resources
 893 *      -EIO    - i/o error
 894 */
 895int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
 896{
 897        int rc;
 898        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
 899        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
 900        struct dmap *dp;
 901        s64 lblkno;
 902        struct metapage *mp;
 903
 904        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 905
 906        /*
 907         * validate extent request:
 908         *
 909         * note: defragfs policy:
 910         *  max 64 blocks will be moved.
 911         *  allocation request size must be satisfied from a single dmap.
 912         */
 913        if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
 914                IREAD_UNLOCK(ipbmap);
 915                return -EINVAL;
 916        }
 917
 918        if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
 919                /* the free space is no longer available */
 920                IREAD_UNLOCK(ipbmap);
 921                return -ENOSPC;
 922        }
 923
 924        /* read in the dmap covering the extent */
 925        lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
 926        mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
 927        if (mp == NULL) {
 928                IREAD_UNLOCK(ipbmap);
 929                return -EIO;
 930        }
 931        dp = (struct dmap *) mp->data;
 932
 933        /* try to allocate the requested extent */
 934        rc = dbAllocNext(bmp, dp, blkno, nblocks);
 935
 936        IREAD_UNLOCK(ipbmap);
 937
 938        if (rc == 0)
 939                mark_metapage_dirty(mp);
 940
 941        release_metapage(mp);
 942
 943        return (rc);
 944}
 945#endif /* _NOTYET */
 946
 947/*
 948 * NAME:        dbReAlloc()
 949 *
 950 * FUNCTION:    attempt to extend a current allocation by a specified
 951 *              number of blocks.
 952 *
 953 *              this routine attempts to satisfy the allocation request
 954 *              by first trying to extend the existing allocation in
 955 *              place by allocating the additional blocks as the blocks
 956 *              immediately following the current allocation.  if these
 957 *              blocks are not available, this routine will attempt to
 958 *              allocate a new set of contiguous blocks large enough
 959 *              to cover the existing allocation plus the additional
 960 *              number of blocks required.
 961 *
 962 * PARAMETERS:
 963 *      ip          -  pointer to in-core inode requiring allocation.
 964 *      blkno       -  starting block of the current allocation.
 965 *      nblocks     -  number of contiguous blocks within the current
 966 *                     allocation.
 967 *      addnblocks  -  number of blocks to add to the allocation.
 968 *      results -      on successful return, set to the starting block number
 969 *                     of the existing allocation if the existing allocation
 970 *                     was extended in place or to a newly allocated contiguous
 971 *                     range if the existing allocation could not be extended
 972 *                     in place.
 973 *
 974 * RETURN VALUES:
 975 *      0       - success
 976 *      -ENOSPC - insufficient disk resources
 977 *      -EIO    - i/o error
 978 */
 979int
 980dbReAlloc(struct inode *ip,
 981          s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
 982{
 983        int rc;
 984
 985        /* try to extend the allocation in place.
 986         */
 987        if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
 988                *results = blkno;
 989                return (0);
 990        } else {
 991                if (rc != -ENOSPC)
 992                        return (rc);
 993        }
 994
 995        /* could not extend the allocation in place, so allocate a
 996         * new set of blocks for the entire request (i.e. try to get
 997         * a range of contiguous blocks large enough to cover the
 998         * existing allocation plus the additional blocks.)
 999         */
1000        return (dbAlloc
1001                (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
1002}
1003
1004
1005/*
1006 * NAME:        dbExtend()
1007 *
1008 * FUNCTION:    attempt to extend a current allocation by a specified
1009 *              number of blocks.
1010 *
1011 *              this routine attempts to satisfy the allocation request
1012 *              by first trying to extend the existing allocation in
1013 *              place by allocating the additional blocks as the blocks
1014 *              immediately following the current allocation.
1015 *
1016 * PARAMETERS:
1017 *      ip          -  pointer to in-core inode requiring allocation.
1018 *      blkno       -  starting block of the current allocation.
1019 *      nblocks     -  number of contiguous blocks within the current
1020 *                     allocation.
1021 *      addnblocks  -  number of blocks to add to the allocation.
1022 *
1023 * RETURN VALUES:
1024 *      0       - success
1025 *      -ENOSPC - insufficient disk resources
1026 *      -EIO    - i/o error
1027 */
1028static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
1029{
1030        struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
1031        s64 lblkno, lastblkno, extblkno;
1032        uint rel_block;
1033        struct metapage *mp;
1034        struct dmap *dp;
1035        int rc;
1036        struct inode *ipbmap = sbi->ipbmap;
1037        struct bmap *bmp;
1038
1039        /*
1040         * We don't want a non-aligned extent to cross a page boundary
1041         */
1042        if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
1043            (rel_block + nblocks + addnblocks > sbi->nbperpage))
1044                return -ENOSPC;
1045
1046        /* get the last block of the current allocation */
1047        lastblkno = blkno + nblocks - 1;
1048
1049        /* determine the block number of the block following
1050         * the existing allocation.
1051         */
1052        extblkno = lastblkno + 1;
1053
1054        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
1055
1056        /* better be within the file system */
1057        bmp = sbi->bmap;
1058        if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
1059                IREAD_UNLOCK(ipbmap);
1060                jfs_error(ip->i_sb,
1061                          "dbExtend: the block is outside the filesystem");
1062                return -EIO;
1063        }
1064
1065        /* we'll attempt to extend the current allocation in place by
1066         * allocating the additional blocks as the blocks immediately
1067         * following the current allocation.  we only try to extend the
1068         * current allocation in place if the number of additional blocks
1069         * can fit into a dmap, the last block of the current allocation
1070         * is not the last block of the file system, and the start of the
1071         * inplace extension is not on an allocation group boundary.
1072         */
1073        if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
1074            (extblkno & (bmp->db_agsize - 1)) == 0) {
1075                IREAD_UNLOCK(ipbmap);
1076                return -ENOSPC;
1077        }
1078
1079        /* get the buffer for the dmap containing the first block
1080         * of the extension.
1081         */
1082        lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
1083        mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
1084        if (mp == NULL) {
1085                IREAD_UNLOCK(ipbmap);
1086                return -EIO;
1087        }
1088
1089        dp = (struct dmap *) mp->data;
1090
1091        /* try to allocate the blocks immediately following the
1092         * current allocation.
1093         */
1094        rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
1095
1096        IREAD_UNLOCK(ipbmap);
1097
1098        /* were we successful ? */
1099        if (rc == 0)
1100                write_metapage(mp);
1101        else
1102                /* we were not successful */
1103                release_metapage(mp);
1104
1105        return (rc);
1106}
1107
1108
1109/*
1110 * NAME:        dbAllocNext()
1111 *
1112 * FUNCTION:    attempt to allocate the blocks of the specified block
1113 *              range within a dmap.
1114 *
1115 * PARAMETERS:
1116 *      bmp     -  pointer to bmap descriptor
1117 *      dp      -  pointer to dmap.
1118 *      blkno   -  starting block number of the range.
1119 *      nblocks -  number of contiguous free blocks of the range.
1120 *
1121 * RETURN VALUES:
1122 *      0       - success
1123 *      -ENOSPC - insufficient disk resources
1124 *      -EIO    - i/o error
1125 *
1126 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1127 */
1128static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
1129                       int nblocks)
1130{
1131        int dbitno, word, rembits, nb, nwords, wbitno, nw;
1132        int l2size;
1133        s8 *leaf;
1134        u32 mask;
1135
1136        if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1137                jfs_error(bmp->db_ipbmap->i_sb,
1138                          "dbAllocNext: Corrupt dmap page");
1139                return -EIO;
1140        }
1141
1142        /* pick up a pointer to the leaves of the dmap tree.
1143         */
1144        leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1145
1146        /* determine the bit number and word within the dmap of the
1147         * starting block.
1148         */
1149        dbitno = blkno & (BPERDMAP - 1);
1150        word = dbitno >> L2DBWORD;
1151
1152        /* check if the specified block range is contained within
1153         * this dmap.
1154         */
1155        if (dbitno + nblocks > BPERDMAP)
1156                return -ENOSPC;
1157
1158        /* check if the starting leaf indicates that anything
1159         * is free.
1160         */
1161        if (leaf[word] == NOFREE)
1162                return -ENOSPC;
1163
1164        /* check the dmaps words corresponding to block range to see
1165         * if the block range is free.  not all bits of the first and
1166         * last words may be contained within the block range.  if this
1167         * is the case, we'll work against those words (i.e. partial first
1168         * and/or last) on an individual basis (a single pass) and examine
1169         * the actual bits to determine if they are free.  a single pass
1170         * will be used for all dmap words fully contained within the
1171         * specified range.  within this pass, the leaves of the dmap
1172         * tree will be examined to determine if the blocks are free. a
1173         * single leaf may describe the free space of multiple dmap
1174         * words, so we may visit only a subset of the actual leaves
1175         * corresponding to the dmap words of the block range.
1176         */
1177        for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
1178                /* determine the bit number within the word and
1179                 * the number of bits within the word.
1180                 */
1181                wbitno = dbitno & (DBWORD - 1);
1182                nb = min(rembits, DBWORD - wbitno);
1183
1184                /* check if only part of the word is to be examined.
1185                 */
1186                if (nb < DBWORD) {
1187                        /* check if the bits are free.
1188                         */
1189                        mask = (ONES << (DBWORD - nb) >> wbitno);
1190                        if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
1191                                return -ENOSPC;
1192
1193                        word += 1;
1194                } else {
1195                        /* one or more dmap words are fully contained
1196                         * within the block range.  determine how many
1197                         * words and how many bits.
1198                         */
1199                        nwords = rembits >> L2DBWORD;
1200                        nb = nwords << L2DBWORD;
1201
1202                        /* now examine the appropriate leaves to determine
1203                         * if the blocks are free.
1204                         */
1205                        while (nwords > 0) {
1206                                /* does the leaf describe any free space ?
1207                                 */
1208                                if (leaf[word] < BUDMIN)
1209                                        return -ENOSPC;
1210
1211                                /* determine the l2 number of bits provided
1212                                 * by this leaf.
1213                                 */
1214                                l2size =
1215                                    min((int)leaf[word], NLSTOL2BSZ(nwords));
1216
1217                                /* determine how many words were handled.
1218                                 */
1219                                nw = BUDSIZE(l2size, BUDMIN);
1220
1221                                nwords -= nw;
1222                                word += nw;
1223                        }
1224                }
1225        }
1226
1227        /* allocate the blocks.
1228         */
1229        return (dbAllocDmap(bmp, dp, blkno, nblocks));
1230}
1231
1232
1233/*
1234 * NAME:        dbAllocNear()
1235 *
1236 * FUNCTION:    attempt to allocate a number of contiguous free blocks near
1237 *              a specified block (hint) within a dmap.
1238 *
1239 *              starting with the dmap leaf that covers the hint, we'll
1240 *              check the next four contiguous leaves for sufficient free
1241 *              space.  if sufficient free space is found, we'll allocate
1242 *              the desired free space.
1243 *
1244 * PARAMETERS:
1245 *      bmp     -  pointer to bmap descriptor
1246 *      dp      -  pointer to dmap.
1247 *      blkno   -  block number to allocate near.
1248 *      nblocks -  actual number of contiguous free blocks desired.
1249 *      l2nb    -  log2 number of contiguous free blocks desired.
1250 *      results -  on successful return, set to the starting block number
1251 *                 of the newly allocated range.
1252 *
1253 * RETURN VALUES:
1254 *      0       - success
1255 *      -ENOSPC - insufficient disk resources
1256 *      -EIO    - i/o error
1257 *
1258 * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
1259 */
1260static int
1261dbAllocNear(struct bmap * bmp,
1262            struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
1263{
1264        int word, lword, rc;
1265        s8 *leaf;
1266
1267        if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
1268                jfs_error(bmp->db_ipbmap->i_sb,
1269                          "dbAllocNear: Corrupt dmap page");
1270                return -EIO;
1271        }
1272
1273        leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
1274
1275        /* determine the word within the dmap that holds the hint
1276         * (i.e. blkno).  also, determine the last word in the dmap
1277         * that we'll include in our examination.
1278         */
1279        word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
1280        lword = min(word + 4, LPERDMAP);
1281
1282        /* examine the leaves for sufficient free space.
1283         */
1284        for (; word < lword; word++) {
1285                /* does the leaf describe sufficient free space ?
1286                 */
1287                if (leaf[word] < l2nb)
1288                        continue;
1289
1290                /* determine the block number within the file system
1291                 * of the first block described by this dmap word.
1292                 */
1293                blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
1294
1295                /* if not all bits of the dmap word are free, get the
1296                 * starting bit number within the dmap word of the required
1297                 * string of free bits and adjust the block number with the
1298                 * value.
1299                 */
1300                if (leaf[word] < BUDMIN)
1301                        blkno +=
1302                            dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
1303
1304                /* allocate the blocks.
1305                 */
1306                if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
1307                        *results = blkno;
1308
1309                return (rc);
1310        }
1311
1312        return -ENOSPC;
1313}
1314
1315
1316/*
1317 * NAME:        dbAllocAG()
1318 *
1319 * FUNCTION:    attempt to allocate the specified number of contiguous
1320 *              free blocks within the specified allocation group.
1321 *
1322 *              unless the allocation group size is equal to the number
1323 *              of blocks per dmap, the dmap control pages will be used to
1324 *              find the required free space, if available.  we start the
1325 *              search at the highest dmap control page level which
1326 *              distinctly describes the allocation group's free space
1327 *              (i.e. the highest level at which the allocation group's
1328 *              free space is not mixed in with that of any other group).
1329 *              in addition, we start the search within this level at a
1330 *              height of the dmapctl dmtree at which the nodes distinctly
1331 *              describe the allocation group's free space.  at this height,
1332 *              the allocation group's free space may be represented by 1
1333 *              or two sub-trees, depending on the allocation group size.
1334 *              we search the top nodes of these subtrees left to right for
1335 *              sufficient free space.  if sufficient free space is found,
1336 *              the subtree is searched to find the leftmost leaf that
1337 *              has free space.  once we have made it to the leaf, we
1338 *              move the search to the next lower level dmap control page
1339 *              corresponding to this leaf.  we continue down the dmap control
1340 *              pages until we find the dmap that contains or starts the
1341 *              sufficient free space and we allocate at this dmap.
1342 *
1343 *              if the allocation group size is equal to the dmap size,
1344 *              we'll start at the dmap corresponding to the allocation
1345 *              group and attempt the allocation at this level.
1346 *
1347 *              the dmap control page search is also not performed if the
1348 *              allocation group is completely free and we go to the first
1349 *              dmap of the allocation group to do the allocation.  this is
1350 *              done because the allocation group may be part (not the first
1351 *              part) of a larger binary buddy system, causing the dmap
1352 *              control pages to indicate no free space (NOFREE) within
1353 *              the allocation group.
1354 *
1355 * PARAMETERS:
1356 *      bmp     -  pointer to bmap descriptor
1357 *      agno    - allocation group number.
1358 *      nblocks -  actual number of contiguous free blocks desired.
1359 *      l2nb    -  log2 number of contiguous free blocks desired.
1360 *      results -  on successful return, set to the starting block number
1361 *                 of the newly allocated range.
1362 *
1363 * RETURN VALUES:
1364 *      0       - success
1365 *      -ENOSPC - insufficient disk resources
1366 *      -EIO    - i/o error
1367 *
1368 * note: IWRITE_LOCK(ipmap) held on entry/exit;
1369 */
1370static int
1371dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
1372{
1373        struct metapage *mp;
1374        struct dmapctl *dcp;
1375        int rc, ti, i, k, m, n, agperlev;
1376        s64 blkno, lblkno;
1377        int budmin;
1378
1379        /* allocation request should not be for more than the
1380         * allocation group size.
1381         */
1382        if (l2nb > bmp->db_agl2size) {
1383                jfs_error(bmp->db_ipbmap->i_sb,
1384                          "dbAllocAG: allocation request is larger than the "
1385                          "allocation group size");
1386                return -EIO;
1387        }
1388
1389        /* determine the starting block number of the allocation
1390         * group.
1391         */
1392        blkno = (s64) agno << bmp->db_agl2size;
1393
1394        /* check if the allocation group size is the minimum allocation
1395         * group size or if the allocation group is completely free. if
1396         * the allocation group size is the minimum size of BPERDMAP (i.e.
1397         * 1 dmap), there is no need to search the dmap control page (below)
1398         * that fully describes the allocation group since the allocation
1399         * group is already fully described by a dmap.  in this case, we
1400         * just call dbAllocCtl() to search the dmap tree and allocate the
1401         * required space if available.
1402         *
1403         * if the allocation group is completely free, dbAllocCtl() is
1404         * also called to allocate the required space.  this is done for
1405         * two reasons.  first, it makes no sense searching the dmap control
1406         * pages for free space when we know that free space exists.  second,
1407         * the dmap control pages may indicate that the allocation group
1408         * has no free space if the allocation group is part (not the first
1409         * part) of a larger binary buddy system.
1410         */
1411        if (bmp->db_agsize == BPERDMAP
1412            || bmp->db_agfree[agno] == bmp->db_agsize) {
1413                rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1414                if ((rc == -ENOSPC) &&
1415                    (bmp->db_agfree[agno] == bmp->db_agsize)) {
1416                        printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
1417                               (unsigned long long) blkno,
1418                               (unsigned long long) nblocks);
1419                        jfs_error(bmp->db_ipbmap->i_sb,
1420                                  "dbAllocAG: dbAllocCtl failed in free AG");
1421                }
1422                return (rc);
1423        }
1424
1425        /* the buffer for the dmap control page that fully describes the
1426         * allocation group.
1427         */
1428        lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
1429        mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1430        if (mp == NULL)
1431                return -EIO;
1432        dcp = (struct dmapctl *) mp->data;
1433        budmin = dcp->budmin;
1434
1435        if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1436                jfs_error(bmp->db_ipbmap->i_sb,
1437                          "dbAllocAG: Corrupt dmapctl page");
1438                release_metapage(mp);
1439                return -EIO;
1440        }
1441
1442        /* search the subtree(s) of the dmap control page that describes
1443         * the allocation group, looking for sufficient free space.  to begin,
1444         * determine how many allocation groups are represented in a dmap
1445         * control page at the control page level (i.e. L0, L1, L2) that
1446         * fully describes an allocation group. next, determine the starting
1447         * tree index of this allocation group within the control page.
1448         */
1449        agperlev =
1450            (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
1451        ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
1452
1453        /* dmap control page trees fan-out by 4 and a single allocation
1454         * group may be described by 1 or 2 subtrees within the ag level
1455         * dmap control page, depending upon the ag size. examine the ag's
1456         * subtrees for sufficient free space, starting with the leftmost
1457         * subtree.
1458         */
1459        for (i = 0; i < bmp->db_agwidth; i++, ti++) {
1460                /* is there sufficient free space ?
1461                 */
1462                if (l2nb > dcp->stree[ti])
1463                        continue;
1464
1465                /* sufficient free space found in a subtree. now search down
1466                 * the subtree to find the leftmost leaf that describes this
1467                 * free space.
1468                 */
1469                for (k = bmp->db_agheight; k > 0; k--) {
1470                        for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
1471                                if (l2nb <= dcp->stree[m + n]) {
1472                                        ti = m + n;
1473                                        break;
1474                                }
1475                        }
1476                        if (n == 4) {
1477                                jfs_error(bmp->db_ipbmap->i_sb,
1478                                          "dbAllocAG: failed descending stree");
1479                                release_metapage(mp);
1480                                return -EIO;
1481                        }
1482                }
1483
1484                /* determine the block number within the file system
1485                 * that corresponds to this leaf.
1486                 */
1487                if (bmp->db_aglevel == 2)
1488                        blkno = 0;
1489                else if (bmp->db_aglevel == 1)
1490                        blkno &= ~(MAXL1SIZE - 1);
1491                else            /* bmp->db_aglevel == 0 */
1492                        blkno &= ~(MAXL0SIZE - 1);
1493
1494                blkno +=
1495                    ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
1496
1497                /* release the buffer in preparation for going down
1498                 * the next level of dmap control pages.
1499                 */
1500                release_metapage(mp);
1501
1502                /* check if we need to continue to search down the lower
1503                 * level dmap control pages.  we need to if the number of
1504                 * blocks required is less than maximum number of blocks
1505                 * described at the next lower level.
1506                 */
1507                if (l2nb < budmin) {
1508
1509                        /* search the lower level dmap control pages to get
1510                         * the starting block number of the dmap that
1511                         * contains or starts off the free space.
1512                         */
1513                        if ((rc =
1514                             dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
1515                                       &blkno))) {
1516                                if (rc == -ENOSPC) {
1517                                        jfs_error(bmp->db_ipbmap->i_sb,
1518                                                  "dbAllocAG: control page "
1519                                                  "inconsistent");
1520                                        return -EIO;
1521                                }
1522                                return (rc);
1523                        }
1524                }
1525
1526                /* allocate the blocks.
1527                 */
1528                rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1529                if (rc == -ENOSPC) {
1530                        jfs_error(bmp->db_ipbmap->i_sb,
1531                                  "dbAllocAG: unable to allocate blocks");
1532                        rc = -EIO;
1533                }
1534                return (rc);
1535        }
1536
1537        /* no space in the allocation group.  release the buffer and
1538         * return -ENOSPC.
1539         */
1540        release_metapage(mp);
1541
1542        return -ENOSPC;
1543}
1544
1545
1546/*
1547 * NAME:        dbAllocAny()
1548 *
1549 * FUNCTION:    attempt to allocate the specified number of contiguous
1550 *              free blocks anywhere in the file system.
1551 *
1552 *              dbAllocAny() attempts to find the sufficient free space by
1553 *              searching down the dmap control pages, starting with the
1554 *              highest level (i.e. L0, L1, L2) control page.  if free space
1555 *              large enough to satisfy the desired free space is found, the
1556 *              desired free space is allocated.
1557 *
1558 * PARAMETERS:
1559 *      bmp     -  pointer to bmap descriptor
1560 *      nblocks  -  actual number of contiguous free blocks desired.
1561 *      l2nb     -  log2 number of contiguous free blocks desired.
1562 *      results -  on successful return, set to the starting block number
1563 *                 of the newly allocated range.
1564 *
1565 * RETURN VALUES:
1566 *      0       - success
1567 *      -ENOSPC - insufficient disk resources
1568 *      -EIO    - i/o error
1569 *
1570 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1571 */
1572static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
1573{
1574        int rc;
1575        s64 blkno = 0;
1576
1577        /* starting with the top level dmap control page, search
1578         * down the dmap control levels for sufficient free space.
1579         * if free space is found, dbFindCtl() returns the starting
1580         * block number of the dmap that contains or starts off the
1581         * range of free space.
1582         */
1583        if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
1584                return (rc);
1585
1586        /* allocate the blocks.
1587         */
1588        rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
1589        if (rc == -ENOSPC) {
1590                jfs_error(bmp->db_ipbmap->i_sb,
1591                          "dbAllocAny: unable to allocate blocks");
1592                return -EIO;
1593        }
1594        return (rc);
1595}
1596
1597
1598/*
1599 * NAME:        dbDiscardAG()
1600 *
1601 * FUNCTION:    attempt to discard (TRIM) all free blocks of specific AG
1602 *
1603 *              algorithm:
1604 *              1) allocate blocks, as large as possible and save them
1605 *                 while holding IWRITE_LOCK on ipbmap
1606 *              2) trim all these saved block/length values
1607 *              3) mark the blocks free again
1608 *
1609 *              benefit:
1610 *              - we work only on one ag at some time, minimizing how long we
1611 *                need to lock ipbmap
1612 *              - reading / writing the fs is possible most time, even on
1613 *                trimming
1614 *
1615 *              downside:
1616 *              - we write two times to the dmapctl and dmap pages
1617 *              - but for me, this seems the best way, better ideas?
1618 *              /TR 2012
1619 *
1620 * PARAMETERS:
1621 *      ip      - pointer to in-core inode
1622 *      agno    - ag to trim
1623 *      minlen  - minimum value of contiguous blocks
1624 *
1625 * RETURN VALUES:
1626 *      s64     - actual number of blocks trimmed
1627 */
1628s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
1629{
1630        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
1631        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
1632        s64 nblocks, blkno;
1633        u64 trimmed = 0;
1634        int rc, l2nb;
1635        struct super_block *sb = ipbmap->i_sb;
1636
1637        struct range2trim {
1638                u64 blkno;
1639                u64 nblocks;
1640        } *totrim, *tt;
1641
1642        /* max blkno / nblocks pairs to trim */
1643        int count = 0, range_cnt;
1644        u64 max_ranges;
1645
1646        /* prevent others from writing new stuff here, while trimming */
1647        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
1648
1649        nblocks = bmp->db_agfree[agno];
1650        max_ranges = nblocks;
1651        do_div(max_ranges, minlen);
1652        range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
1653        totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
1654        if (totrim == NULL) {
1655                jfs_error(bmp->db_ipbmap->i_sb,
1656                          "dbDiscardAG: no memory for trim array");
1657                IWRITE_UNLOCK(ipbmap);
1658                return 0;
1659        }
1660
1661        tt = totrim;
1662        while (nblocks >= minlen) {
1663                l2nb = BLKSTOL2(nblocks);
1664
1665                /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
1666                rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
1667                if (rc == 0) {
1668                        tt->blkno = blkno;
1669                        tt->nblocks = nblocks;
1670                        tt++; count++;
1671
1672                        /* the whole ag is free, trim now */
1673                        if (bmp->db_agfree[agno] == 0)
1674                                break;
1675
1676                        /* give a hint for the next while */
1677                        nblocks = bmp->db_agfree[agno];
1678                        continue;
1679                } else if (rc == -ENOSPC) {
1680                        /* search for next smaller log2 block */
1681                        l2nb = BLKSTOL2(nblocks) - 1;
1682                        nblocks = 1 << l2nb;
1683                } else {
1684                        /* Trim any already allocated blocks */
1685                        jfs_error(bmp->db_ipbmap->i_sb,
1686                                "dbDiscardAG: -EIO");
1687                        break;
1688                }
1689
1690                /* check, if our trim array is full */
1691                if (unlikely(count >= range_cnt - 1))
1692                        break;
1693        }
1694        IWRITE_UNLOCK(ipbmap);
1695
1696        tt->nblocks = 0; /* mark the current end */
1697        for (tt = totrim; tt->nblocks != 0; tt++) {
1698                /* when mounted with online discard, dbFree() will
1699                 * call jfs_issue_discard() itself */
1700                if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
1701                        jfs_issue_discard(ip, tt->blkno, tt->nblocks);
1702                dbFree(ip, tt->blkno, tt->nblocks);
1703                trimmed += tt->nblocks;
1704        }
1705        kfree(totrim);
1706
1707        return trimmed;
1708}
1709
1710/*
1711 * NAME:        dbFindCtl()
1712 *
1713 * FUNCTION:    starting at a specified dmap control page level and block
1714 *              number, search down the dmap control levels for a range of
1715 *              contiguous free blocks large enough to satisfy an allocation
1716 *              request for the specified number of free blocks.
1717 *
1718 *              if sufficient contiguous free blocks are found, this routine
1719 *              returns the starting block number within a dmap page that
1720 *              contains or starts a range of contiqious free blocks that
1721 *              is sufficient in size.
1722 *
1723 * PARAMETERS:
1724 *      bmp     -  pointer to bmap descriptor
1725 *      level   -  starting dmap control page level.
1726 *      l2nb    -  log2 number of contiguous free blocks desired.
1727 *      *blkno  -  on entry, starting block number for conducting the search.
1728 *                 on successful return, the first block within a dmap page
1729 *                 that contains or starts a range of contiguous free blocks.
1730 *
1731 * RETURN VALUES:
1732 *      0       - success
1733 *      -ENOSPC - insufficient disk resources
1734 *      -EIO    - i/o error
1735 *
1736 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1737 */
1738static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
1739{
1740        int rc, leafidx, lev;
1741        s64 b, lblkno;
1742        struct dmapctl *dcp;
1743        int budmin;
1744        struct metapage *mp;
1745
1746        /* starting at the specified dmap control page level and block
1747         * number, search down the dmap control levels for the starting
1748         * block number of a dmap page that contains or starts off
1749         * sufficient free blocks.
1750         */
1751        for (lev = level, b = *blkno; lev >= 0; lev--) {
1752                /* get the buffer of the dmap control page for the block
1753                 * number and level (i.e. L0, L1, L2).
1754                 */
1755                lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
1756                mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1757                if (mp == NULL)
1758                        return -EIO;
1759                dcp = (struct dmapctl *) mp->data;
1760                budmin = dcp->budmin;
1761
1762                if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
1763                        jfs_error(bmp->db_ipbmap->i_sb,
1764                                  "dbFindCtl: Corrupt dmapctl page");
1765                        release_metapage(mp);
1766                        return -EIO;
1767                }
1768
1769                /* search the tree within the dmap control page for
1770                 * sufficient free space.  if sufficient free space is found,
1771                 * dbFindLeaf() returns the index of the leaf at which
1772                 * free space was found.
1773                 */
1774                rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
1775
1776                /* release the buffer.
1777                 */
1778                release_metapage(mp);
1779
1780                /* space found ?
1781                 */
1782                if (rc) {
1783                        if (lev != level) {
1784                                jfs_error(bmp->db_ipbmap->i_sb,
1785                                          "dbFindCtl: dmap inconsistent");
1786                                return -EIO;
1787                        }
1788                        return -ENOSPC;
1789                }
1790
1791                /* adjust the block number to reflect the location within
1792                 * the dmap control page (i.e. the leaf) at which free
1793                 * space was found.
1794                 */
1795                b += (((s64) leafidx) << budmin);
1796
1797                /* we stop the search at this dmap control page level if
1798                 * the number of blocks required is greater than or equal
1799                 * to the maximum number of blocks described at the next
1800                 * (lower) level.
1801                 */
1802                if (l2nb >= budmin)
1803                        break;
1804        }
1805
1806        *blkno = b;
1807        return (0);
1808}
1809
1810
1811/*
1812 * NAME:        dbAllocCtl()
1813 *
1814 * FUNCTION:    attempt to allocate a specified number of contiguous
1815 *              blocks starting within a specific dmap.
1816 *
1817 *              this routine is called by higher level routines that search
1818 *              the dmap control pages above the actual dmaps for contiguous
1819 *              free space.  the result of successful searches by these
1820 *              routines are the starting block numbers within dmaps, with
1821 *              the dmaps themselves containing the desired contiguous free
1822 *              space or starting a contiguous free space of desired size
1823 *              that is made up of the blocks of one or more dmaps. these
1824 *              calls should not fail due to insufficent resources.
1825 *
1826 *              this routine is called in some cases where it is not known
1827 *              whether it will fail due to insufficient resources.  more
1828 *              specifically, this occurs when allocating from an allocation
1829 *              group whose size is equal to the number of blocks per dmap.
1830 *              in this case, the dmap control pages are not examined prior
1831 *              to calling this routine (to save pathlength) and the call
1832 *              might fail.
1833 *
1834 *              for a request size that fits within a dmap, this routine relies
1835 *              upon the dmap's dmtree to find the requested contiguous free
1836 *              space.  for request sizes that are larger than a dmap, the
1837 *              requested free space will start at the first block of the
1838 *              first dmap (i.e. blkno).
1839 *
1840 * PARAMETERS:
1841 *      bmp     -  pointer to bmap descriptor
1842 *      nblocks  -  actual number of contiguous free blocks to allocate.
1843 *      l2nb     -  log2 number of contiguous free blocks to allocate.
1844 *      blkno    -  starting block number of the dmap to start the allocation
1845 *                  from.
1846 *      results -  on successful return, set to the starting block number
1847 *                 of the newly allocated range.
1848 *
1849 * RETURN VALUES:
1850 *      0       - success
1851 *      -ENOSPC - insufficient disk resources
1852 *      -EIO    - i/o error
1853 *
1854 * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
1855 */
1856static int
1857dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
1858{
1859        int rc, nb;
1860        s64 b, lblkno, n;
1861        struct metapage *mp;
1862        struct dmap *dp;
1863
1864        /* check if the allocation request is confined to a single dmap.
1865         */
1866        if (l2nb <= L2BPERDMAP) {
1867                /* get the buffer for the dmap.
1868                 */
1869                lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
1870                mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1871                if (mp == NULL)
1872                        return -EIO;
1873                dp = (struct dmap *) mp->data;
1874
1875                /* try to allocate the blocks.
1876                 */
1877                rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
1878                if (rc == 0)
1879                        mark_metapage_dirty(mp);
1880
1881                release_metapage(mp);
1882
1883                return (rc);
1884        }
1885
1886        /* allocation request involving multiple dmaps. it must start on
1887         * a dmap boundary.
1888         */
1889        assert((blkno & (BPERDMAP - 1)) == 0);
1890
1891        /* allocate the blocks dmap by dmap.
1892         */
1893        for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
1894                /* get the buffer for the dmap.
1895                 */
1896                lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1897                mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1898                if (mp == NULL) {
1899                        rc = -EIO;
1900                        goto backout;
1901                }
1902                dp = (struct dmap *) mp->data;
1903
1904                /* the dmap better be all free.
1905                 */
1906                if (dp->tree.stree[ROOT] != L2BPERDMAP) {
1907                        release_metapage(mp);
1908                        jfs_error(bmp->db_ipbmap->i_sb,
1909                                  "dbAllocCtl: the dmap is not all free");
1910                        rc = -EIO;
1911                        goto backout;
1912                }
1913
1914                /* determine how many blocks to allocate from this dmap.
1915                 */
1916                nb = min(n, (s64)BPERDMAP);
1917
1918                /* allocate the blocks from the dmap.
1919                 */
1920                if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
1921                        release_metapage(mp);
1922                        goto backout;
1923                }
1924
1925                /* write the buffer.
1926                 */
1927                write_metapage(mp);
1928        }
1929
1930        /* set the results (starting block number) and return.
1931         */
1932        *results = blkno;
1933        return (0);
1934
1935        /* something failed in handling an allocation request involving
1936         * multiple dmaps.  we'll try to clean up by backing out any
1937         * allocation that has already happened for this request.  if
1938         * we fail in backing out the allocation, we'll mark the file
1939         * system to indicate that blocks have been leaked.
1940         */
1941      backout:
1942
1943        /* try to backout the allocations dmap by dmap.
1944         */
1945        for (n = nblocks - n, b = blkno; n > 0;
1946             n -= BPERDMAP, b += BPERDMAP) {
1947                /* get the buffer for this dmap.
1948                 */
1949                lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
1950                mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
1951                if (mp == NULL) {
1952                        /* could not back out.  mark the file system
1953                         * to indicate that we have leaked blocks.
1954                         */
1955                        jfs_error(bmp->db_ipbmap->i_sb,
1956                                  "dbAllocCtl: I/O Error: Block Leakage.");
1957                        continue;
1958                }
1959                dp = (struct dmap *) mp->data;
1960
1961                /* free the blocks is this dmap.
1962                 */
1963                if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
1964                        /* could not back out.  mark the file system
1965                         * to indicate that we have leaked blocks.
1966                         */
1967                        release_metapage(mp);
1968                        jfs_error(bmp->db_ipbmap->i_sb,
1969                                  "dbAllocCtl: Block Leakage.");
1970                        continue;
1971                }
1972
1973                /* write the buffer.
1974                 */
1975                write_metapage(mp);
1976        }
1977
1978        return (rc);
1979}
1980
1981
1982/*
1983 * NAME:        dbAllocDmapLev()
1984 *
1985 * FUNCTION:    attempt to allocate a specified number of contiguous blocks
1986 *              from a specified dmap.
1987 *
1988 *              this routine checks if the contiguous blocks are available.
1989 *              if so, nblocks of blocks are allocated; otherwise, ENOSPC is
1990 *              returned.
1991 *
1992 * PARAMETERS:
1993 *      mp      -  pointer to bmap descriptor
1994 *      dp      -  pointer to dmap to attempt to allocate blocks from.
1995 *      l2nb    -  log2 number of contiguous block desired.
1996 *      nblocks -  actual number of contiguous block desired.
1997 *      results -  on successful return, set to the starting block number
1998 *                 of the newly allocated range.
1999 *
2000 * RETURN VALUES:
2001 *      0       - success
2002 *      -ENOSPC - insufficient disk resources
2003 *      -EIO    - i/o error
2004 *
2005 * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
2006 *      IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
2007 */
2008static int
2009dbAllocDmapLev(struct bmap * bmp,
2010               struct dmap * dp, int nblocks, int l2nb, s64 * results)
2011{
2012        s64 blkno;
2013        int leafidx, rc;
2014
2015        /* can't be more than a dmaps worth of blocks */
2016        assert(l2nb <= L2BPERDMAP);
2017
2018        /* search the tree within the dmap page for sufficient
2019         * free space.  if sufficient free space is found, dbFindLeaf()
2020         * returns the index of the leaf at which free space was found.
2021         */
2022        if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
2023                return -ENOSPC;
2024
2025        /* determine the block number within the file system corresponding
2026         * to the leaf at which free space was found.
2027         */
2028        blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
2029
2030        /* if not all bits of the dmap word are free, get the starting
2031         * bit number within the dmap word of the required string of free
2032         * bits and adjust the block number with this value.
2033         */
2034        if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
2035                blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
2036
2037        /* allocate the blocks */
2038        if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
2039                *results = blkno;
2040
2041        return (rc);
2042}
2043
2044
2045/*
2046 * NAME:        dbAllocDmap()
2047 *
2048 * FUNCTION:    adjust the disk allocation map to reflect the allocation
2049 *              of a specified block range within a dmap.
2050 *
2051 *              this routine allocates the specified blocks from the dmap
2052 *              through a call to dbAllocBits(). if the allocation of the
2053 *              block range causes the maximum string of free blocks within
2054 *              the dmap to change (i.e. the value of the root of the dmap's
2055 *              dmtree), this routine will cause this change to be reflected
2056 *              up through the appropriate levels of the dmap control pages
2057 *              by a call to dbAdjCtl() for the L0 dmap control page that
2058 *              covers this dmap.
2059 *
2060 * PARAMETERS:
2061 *      bmp     -  pointer to bmap descriptor
2062 *      dp      -  pointer to dmap to allocate the block range from.
2063 *      blkno   -  starting block number of the block to be allocated.
2064 *      nblocks -  number of blocks to be allocated.
2065 *
2066 * RETURN VALUES:
2067 *      0       - success
2068 *      -EIO    - i/o error
2069 *
2070 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2071 */
2072static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2073                       int nblocks)
2074{
2075        s8 oldroot;
2076        int rc;
2077
2078        /* save the current value of the root (i.e. maximum free string)
2079         * of the dmap tree.
2080         */
2081        oldroot = dp->tree.stree[ROOT];
2082
2083        /* allocate the specified (blocks) bits */
2084        dbAllocBits(bmp, dp, blkno, nblocks);
2085
2086        /* if the root has not changed, done. */
2087        if (dp->tree.stree[ROOT] == oldroot)
2088                return (0);
2089
2090        /* root changed. bubble the change up to the dmap control pages.
2091         * if the adjustment of the upper level control pages fails,
2092         * backout the bit allocation (thus making everything consistent).
2093         */
2094        if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
2095                dbFreeBits(bmp, dp, blkno, nblocks);
2096
2097        return (rc);
2098}
2099
2100
2101/*
2102 * NAME:        dbFreeDmap()
2103 *
2104 * FUNCTION:    adjust the disk allocation map to reflect the allocation
2105 *              of a specified block range within a dmap.
2106 *
2107 *              this routine frees the specified blocks from the dmap through
2108 *              a call to dbFreeBits(). if the deallocation of the block range
2109 *              causes the maximum string of free blocks within the dmap to
2110 *              change (i.e. the value of the root of the dmap's dmtree), this
2111 *              routine will cause this change to be reflected up through the
2112 *              appropriate levels of the dmap control pages by a call to
2113 *              dbAdjCtl() for the L0 dmap control page that covers this dmap.
2114 *
2115 * PARAMETERS:
2116 *      bmp     -  pointer to bmap descriptor
2117 *      dp      -  pointer to dmap to free the block range from.
2118 *      blkno   -  starting block number of the block to be freed.
2119 *      nblocks -  number of blocks to be freed.
2120 *
2121 * RETURN VALUES:
2122 *      0       - success
2123 *      -EIO    - i/o error
2124 *
2125 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2126 */
2127static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
2128                      int nblocks)
2129{
2130        s8 oldroot;
2131        int rc = 0, word;
2132
2133        /* save the current value of the root (i.e. maximum free string)
2134         * of the dmap tree.
2135         */
2136        oldroot = dp->tree.stree[ROOT];
2137
2138        /* free the specified (blocks) bits */
2139        rc = dbFreeBits(bmp, dp, blkno, nblocks);
2140
2141        /* if error or the root has not changed, done. */
2142        if (rc || (dp->tree.stree[ROOT] == oldroot))
2143                return (rc);
2144
2145        /* root changed. bubble the change up to the dmap control pages.
2146         * if the adjustment of the upper level control pages fails,
2147         * backout the deallocation.
2148         */
2149        if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
2150                word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
2151
2152                /* as part of backing out the deallocation, we will have
2153                 * to back split the dmap tree if the deallocation caused
2154                 * the freed blocks to become part of a larger binary buddy
2155                 * system.
2156                 */
2157                if (dp->tree.stree[word] == NOFREE)
2158                        dbBackSplit((dmtree_t *) & dp->tree, word);
2159
2160                dbAllocBits(bmp, dp, blkno, nblocks);
2161        }
2162
2163        return (rc);
2164}
2165
2166
2167/*
2168 * NAME:        dbAllocBits()
2169 *
2170 * FUNCTION:    allocate a specified block range from a dmap.
2171 *
2172 *              this routine updates the dmap to reflect the working
2173 *              state allocation of the specified block range. it directly
2174 *              updates the bits of the working map and causes the adjustment
2175 *              of the binary buddy system described by the dmap's dmtree
2176 *              leaves to reflect the bits allocated.  it also causes the
2177 *              dmap's dmtree, as a whole, to reflect the allocated range.
2178 *
2179 * PARAMETERS:
2180 *      bmp     -  pointer to bmap descriptor
2181 *      dp      -  pointer to dmap to allocate bits from.
2182 *      blkno   -  starting block number of the bits to be allocated.
2183 *      nblocks -  number of bits to be allocated.
2184 *
2185 * RETURN VALUES: none
2186 *
2187 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2188 */
2189static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2190                        int nblocks)
2191{
2192        int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2193        dmtree_t *tp = (dmtree_t *) & dp->tree;
2194        int size;
2195        s8 *leaf;
2196
2197        /* pick up a pointer to the leaves of the dmap tree */
2198        leaf = dp->tree.stree + LEAFIND;
2199
2200        /* determine the bit number and word within the dmap of the
2201         * starting block.
2202         */
2203        dbitno = blkno & (BPERDMAP - 1);
2204        word = dbitno >> L2DBWORD;
2205
2206        /* block range better be within the dmap */
2207        assert(dbitno + nblocks <= BPERDMAP);
2208
2209        /* allocate the bits of the dmap's words corresponding to the block
2210         * range. not all bits of the first and last words may be contained
2211         * within the block range.  if this is the case, we'll work against
2212         * those words (i.e. partial first and/or last) on an individual basis
2213         * (a single pass), allocating the bits of interest by hand and
2214         * updating the leaf corresponding to the dmap word. a single pass
2215         * will be used for all dmap words fully contained within the
2216         * specified range.  within this pass, the bits of all fully contained
2217         * dmap words will be marked as free in a single shot and the leaves
2218         * will be updated. a single leaf may describe the free space of
2219         * multiple dmap words, so we may update only a subset of the actual
2220         * leaves corresponding to the dmap words of the block range.
2221         */
2222        for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2223                /* determine the bit number within the word and
2224                 * the number of bits within the word.
2225                 */
2226                wbitno = dbitno & (DBWORD - 1);
2227                nb = min(rembits, DBWORD - wbitno);
2228
2229                /* check if only part of a word is to be allocated.
2230                 */
2231                if (nb < DBWORD) {
2232                        /* allocate (set to 1) the appropriate bits within
2233                         * this dmap word.
2234                         */
2235                        dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
2236                                                      >> wbitno);
2237
2238                        /* update the leaf for this dmap word. in addition
2239                         * to setting the leaf value to the binary buddy max
2240                         * of the updated dmap word, dbSplit() will split
2241                         * the binary system of the leaves if need be.
2242                         */
2243                        dbSplit(tp, word, BUDMIN,
2244                                dbMaxBud((u8 *) & dp->wmap[word]));
2245
2246                        word += 1;
2247                } else {
2248                        /* one or more dmap words are fully contained
2249                         * within the block range.  determine how many
2250                         * words and allocate (set to 1) the bits of these
2251                         * words.
2252                         */
2253                        nwords = rembits >> L2DBWORD;
2254                        memset(&dp->wmap[word], (int) ONES, nwords * 4);
2255
2256                        /* determine how many bits.
2257                         */
2258                        nb = nwords << L2DBWORD;
2259
2260                        /* now update the appropriate leaves to reflect
2261                         * the allocated words.
2262                         */
2263                        for (; nwords > 0; nwords -= nw) {
2264                                if (leaf[word] < BUDMIN) {
2265                                        jfs_error(bmp->db_ipbmap->i_sb,
2266                                                  "dbAllocBits: leaf page "
2267                                                  "corrupt");
2268                                        break;
2269                                }
2270
2271                                /* determine what the leaf value should be
2272                                 * updated to as the minimum of the l2 number
2273                                 * of bits being allocated and the l2 number
2274                                 * of bits currently described by this leaf.
2275                                 */
2276                                size = min((int)leaf[word], NLSTOL2BSZ(nwords));
2277
2278                                /* update the leaf to reflect the allocation.
2279                                 * in addition to setting the leaf value to
2280                                 * NOFREE, dbSplit() will split the binary
2281                                 * system of the leaves to reflect the current
2282                                 * allocation (size).
2283                                 */
2284                                dbSplit(tp, word, size, NOFREE);
2285
2286                                /* get the number of dmap words handled */
2287                                nw = BUDSIZE(size, BUDMIN);
2288                                word += nw;
2289                        }
2290                }
2291        }
2292
2293        /* update the free count for this dmap */
2294        le32_add_cpu(&dp->nfree, -nblocks);
2295
2296        BMAP_LOCK(bmp);
2297
2298        /* if this allocation group is completely free,
2299         * update the maximum allocation group number if this allocation
2300         * group is the new max.
2301         */
2302        agno = blkno >> bmp->db_agl2size;
2303        if (agno > bmp->db_maxag)
2304                bmp->db_maxag = agno;
2305
2306        /* update the free count for the allocation group and map */
2307        bmp->db_agfree[agno] -= nblocks;
2308        bmp->db_nfree -= nblocks;
2309
2310        BMAP_UNLOCK(bmp);
2311}
2312
2313
2314/*
2315 * NAME:        dbFreeBits()
2316 *
2317 * FUNCTION:    free a specified block range from a dmap.
2318 *
2319 *              this routine updates the dmap to reflect the working
2320 *              state allocation of the specified block range. it directly
2321 *              updates the bits of the working map and causes the adjustment
2322 *              of the binary buddy system described by the dmap's dmtree
2323 *              leaves to reflect the bits freed.  it also causes the dmap's
2324 *              dmtree, as a whole, to reflect the deallocated range.
2325 *
2326 * PARAMETERS:
2327 *      bmp     -  pointer to bmap descriptor
2328 *      dp      -  pointer to dmap to free bits from.
2329 *      blkno   -  starting block number of the bits to be freed.
2330 *      nblocks -  number of bits to be freed.
2331 *
2332 * RETURN VALUES: 0 for success
2333 *
2334 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2335 */
2336static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
2337                       int nblocks)
2338{
2339        int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
2340        dmtree_t *tp = (dmtree_t *) & dp->tree;
2341        int rc = 0;
2342        int size;
2343
2344        /* determine the bit number and word within the dmap of the
2345         * starting block.
2346         */
2347        dbitno = blkno & (BPERDMAP - 1);
2348        word = dbitno >> L2DBWORD;
2349
2350        /* block range better be within the dmap.
2351         */
2352        assert(dbitno + nblocks <= BPERDMAP);
2353
2354        /* free the bits of the dmaps words corresponding to the block range.
2355         * not all bits of the first and last words may be contained within
2356         * the block range.  if this is the case, we'll work against those
2357         * words (i.e. partial first and/or last) on an individual basis
2358         * (a single pass), freeing the bits of interest by hand and updating
2359         * the leaf corresponding to the dmap word. a single pass will be used
2360         * for all dmap words fully contained within the specified range.
2361         * within this pass, the bits of all fully contained dmap words will
2362         * be marked as free in a single shot and the leaves will be updated. a
2363         * single leaf may describe the free space of multiple dmap words,
2364         * so we may update only a subset of the actual leaves corresponding
2365         * to the dmap words of the block range.
2366         *
2367         * dbJoin() is used to update leaf values and will join the binary
2368         * buddy system of the leaves if the new leaf values indicate this
2369         * should be done.
2370         */
2371        for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
2372                /* determine the bit number within the word and
2373                 * the number of bits within the word.
2374                 */
2375                wbitno = dbitno & (DBWORD - 1);
2376                nb = min(rembits, DBWORD - wbitno);
2377
2378                /* check if only part of a word is to be freed.
2379                 */
2380                if (nb < DBWORD) {
2381                        /* free (zero) the appropriate bits within this
2382                         * dmap word.
2383                         */
2384                        dp->wmap[word] &=
2385                            cpu_to_le32(~(ONES << (DBWORD - nb)
2386                                          >> wbitno));
2387
2388                        /* update the leaf for this dmap word.
2389                         */
2390                        rc = dbJoin(tp, word,
2391                                    dbMaxBud((u8 *) & dp->wmap[word]));
2392                        if (rc)
2393                                return rc;
2394
2395                        word += 1;
2396                } else {
2397                        /* one or more dmap words are fully contained
2398                         * within the block range.  determine how many
2399                         * words and free (zero) the bits of these words.
2400                         */
2401                        nwords = rembits >> L2DBWORD;
2402                        memset(&dp->wmap[word], 0, nwords * 4);
2403
2404                        /* determine how many bits.
2405                         */
2406                        nb = nwords << L2DBWORD;
2407
2408                        /* now update the appropriate leaves to reflect
2409                         * the freed words.
2410                         */
2411                        for (; nwords > 0; nwords -= nw) {
2412                                /* determine what the leaf value should be
2413                                 * updated to as the minimum of the l2 number
2414                                 * of bits being freed and the l2 (max) number
2415                                 * of bits that can be described by this leaf.
2416                                 */
2417                                size =
2418                                    min(LITOL2BSZ
2419                                        (word, L2LPERDMAP, BUDMIN),
2420                                        NLSTOL2BSZ(nwords));
2421
2422                                /* update the leaf.
2423                                 */
2424                                rc = dbJoin(tp, word, size);
2425                                if (rc)
2426                                        return rc;
2427
2428                                /* get the number of dmap words handled.
2429                                 */
2430                                nw = BUDSIZE(size, BUDMIN);
2431                                word += nw;
2432                        }
2433                }
2434        }
2435
2436        /* update the free count for this dmap.
2437         */
2438        le32_add_cpu(&dp->nfree, nblocks);
2439
2440        BMAP_LOCK(bmp);
2441
2442        /* update the free count for the allocation group and
2443         * map.
2444         */
2445        agno = blkno >> bmp->db_agl2size;
2446        bmp->db_nfree += nblocks;
2447        bmp->db_agfree[agno] += nblocks;
2448
2449        /* check if this allocation group is not completely free and
2450         * if it is currently the maximum (rightmost) allocation group.
2451         * if so, establish the new maximum allocation group number by
2452         * searching left for the first allocation group with allocation.
2453         */
2454        if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
2455            (agno == bmp->db_numag - 1 &&
2456             bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
2457                while (bmp->db_maxag > 0) {
2458                        bmp->db_maxag -= 1;
2459                        if (bmp->db_agfree[bmp->db_maxag] !=
2460                            bmp->db_agsize)
2461                                break;
2462                }
2463
2464                /* re-establish the allocation group preference if the
2465                 * current preference is right of the maximum allocation
2466                 * group.
2467                 */
2468                if (bmp->db_agpref > bmp->db_maxag)
2469                        bmp->db_agpref = bmp->db_maxag;
2470        }
2471
2472        BMAP_UNLOCK(bmp);
2473
2474        return 0;
2475}
2476
2477
2478/*
2479 * NAME:        dbAdjCtl()
2480 *
2481 * FUNCTION:    adjust a dmap control page at a specified level to reflect
2482 *              the change in a lower level dmap or dmap control page's
2483 *              maximum string of free blocks (i.e. a change in the root
2484 *              of the lower level object's dmtree) due to the allocation
2485 *              or deallocation of a range of blocks with a single dmap.
2486 *
2487 *              on entry, this routine is provided with the new value of
2488 *              the lower level dmap or dmap control page root and the
2489 *              starting block number of the block range whose allocation
2490 *              or deallocation resulted in the root change.  this range
2491 *              is respresented by a single leaf of the current dmapctl
2492 *              and the leaf will be updated with this value, possibly
2493 *              causing a binary buddy system within the leaves to be
2494 *              split or joined.  the update may also cause the dmapctl's
2495 *              dmtree to be updated.
2496 *
2497 *              if the adjustment of the dmap control page, itself, causes its
2498 *              root to change, this change will be bubbled up to the next dmap
2499 *              control level by a recursive call to this routine, specifying
2500 *              the new root value and the next dmap control page level to
2501 *              be adjusted.
2502 * PARAMETERS:
2503 *      bmp     -  pointer to bmap descriptor
2504 *      blkno   -  the first block of a block range within a dmap.  it is
2505 *                 the allocation or deallocation of this block range that
2506 *                 requires the dmap control page to be adjusted.
2507 *      newval  -  the new value of the lower level dmap or dmap control
2508 *                 page root.
2509 *      alloc   -  'true' if adjustment is due to an allocation.
2510 *      level   -  current level of dmap control page (i.e. L0, L1, L2) to
2511 *                 be adjusted.
2512 *
2513 * RETURN VALUES:
2514 *      0       - success
2515 *      -EIO    - i/o error
2516 *
2517 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2518 */
2519static int
2520dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
2521{
2522        struct metapage *mp;
2523        s8 oldroot;
2524        int oldval;
2525        s64 lblkno;
2526        struct dmapctl *dcp;
2527        int rc, leafno, ti;
2528
2529        /* get the buffer for the dmap control page for the specified
2530         * block number and control page level.
2531         */
2532        lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
2533        mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
2534        if (mp == NULL)
2535                return -EIO;
2536        dcp = (struct dmapctl *) mp->data;
2537
2538        if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
2539                jfs_error(bmp->db_ipbmap->i_sb,
2540                          "dbAdjCtl: Corrupt dmapctl page");
2541                release_metapage(mp);
2542                return -EIO;
2543        }
2544
2545        /* determine the leaf number corresponding to the block and
2546         * the index within the dmap control tree.
2547         */
2548        leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
2549        ti = leafno + le32_to_cpu(dcp->leafidx);
2550
2551        /* save the current leaf value and the current root level (i.e.
2552         * maximum l2 free string described by this dmapctl).
2553         */
2554        oldval = dcp->stree[ti];
2555        oldroot = dcp->stree[ROOT];
2556
2557        /* check if this is a control page update for an allocation.
2558         * if so, update the leaf to reflect the new leaf value using
2559         * dbSplit(); otherwise (deallocation), use dbJoin() to update
2560         * the leaf with the new value.  in addition to updating the
2561         * leaf, dbSplit() will also split the binary buddy system of
2562         * the leaves, if required, and bubble new values within the
2563         * dmapctl tree, if required.  similarly, dbJoin() will join
2564         * the binary buddy system of leaves and bubble new values up
2565         * the dmapctl tree as required by the new leaf value.
2566         */
2567        if (alloc) {
2568                /* check if we are in the middle of a binary buddy
2569                 * system.  this happens when we are performing the
2570                 * first allocation out of an allocation group that
2571                 * is part (not the first part) of a larger binary
2572                 * buddy system.  if we are in the middle, back split
2573                 * the system prior to calling dbSplit() which assumes
2574                 * that it is at the front of a binary buddy system.
2575                 */
2576                if (oldval == NOFREE) {
2577                        rc = dbBackSplit((dmtree_t *) dcp, leafno);
2578                        if (rc)
2579                                return rc;
2580                        oldval = dcp->stree[ti];
2581                }
2582                dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
2583        } else {
2584                rc = dbJoin((dmtree_t *) dcp, leafno, newval);
2585                if (rc)
2586                        return rc;
2587        }
2588
2589        /* check if the root of the current dmap control page changed due
2590         * to the update and if the current dmap control page is not at
2591         * the current top level (i.e. L0, L1, L2) of the map.  if so (i.e.
2592         * root changed and this is not the top level), call this routine
2593         * again (recursion) for the next higher level of the mapping to
2594         * reflect the change in root for the current dmap control page.
2595         */
2596        if (dcp->stree[ROOT] != oldroot) {
2597                /* are we below the top level of the map.  if so,
2598                 * bubble the root up to the next higher level.
2599                 */
2600                if (level < bmp->db_maxlevel) {
2601                        /* bubble up the new root of this dmap control page to
2602                         * the next level.
2603                         */
2604                        if ((rc =
2605                             dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
2606                                      level + 1))) {
2607                                /* something went wrong in bubbling up the new
2608                                 * root value, so backout the changes to the
2609                                 * current dmap control page.
2610                                 */
2611                                if (alloc) {
2612                                        dbJoin((dmtree_t *) dcp, leafno,
2613                                               oldval);
2614                                } else {
2615                                        /* the dbJoin() above might have
2616                                         * caused a larger binary buddy system
2617                                         * to form and we may now be in the
2618                                         * middle of it.  if this is the case,
2619                                         * back split the buddies.
2620                                         */
2621                                        if (dcp->stree[ti] == NOFREE)
2622                                                dbBackSplit((dmtree_t *)
2623                                                            dcp, leafno);
2624                                        dbSplit((dmtree_t *) dcp, leafno,
2625                                                dcp->budmin, oldval);
2626                                }
2627
2628                                /* release the buffer and return the error.
2629                                 */
2630                                release_metapage(mp);
2631                                return (rc);
2632                        }
2633                } else {
2634                        /* we're at the top level of the map. update
2635                         * the bmap control page to reflect the size
2636                         * of the maximum free buddy system.
2637                         */
2638                        assert(level == bmp->db_maxlevel);
2639                        if (bmp->db_maxfreebud != oldroot) {
2640                                jfs_error(bmp->db_ipbmap->i_sb,
2641                                          "dbAdjCtl: the maximum free buddy is "
2642                                          "not the old root");
2643                        }
2644                        bmp->db_maxfreebud = dcp->stree[ROOT];
2645                }
2646        }
2647
2648        /* write the buffer.
2649         */
2650        write_metapage(mp);
2651
2652        return (0);
2653}
2654
2655
2656/*
2657 * NAME:        dbSplit()
2658 *
2659 * FUNCTION:    update the leaf of a dmtree with a new value, splitting
2660 *              the leaf from the binary buddy system of the dmtree's
2661 *              leaves, as required.
2662 *
2663 * PARAMETERS:
2664 *      tp      - pointer to the tree containing the leaf.
2665 *      leafno  - the number of the leaf to be updated.
2666 *      splitsz - the size the binary buddy system starting at the leaf
2667 *                must be split to, specified as the log2 number of blocks.
2668 *      newval  - the new value for the leaf.
2669 *
2670 * RETURN VALUES: none
2671 *
2672 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2673 */
2674static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
2675{
2676        int budsz;
2677        int cursz;
2678        s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2679
2680        /* check if the leaf needs to be split.
2681         */
2682        if (leaf[leafno] > tp->dmt_budmin) {
2683                /* the split occurs by cutting the buddy system in half
2684                 * at the specified leaf until we reach the specified
2685                 * size.  pick up the starting split size (current size
2686                 * - 1 in l2) and the corresponding buddy size.
2687                 */
2688                cursz = leaf[leafno] - 1;
2689                budsz = BUDSIZE(cursz, tp->dmt_budmin);
2690
2691                /* split until we reach the specified size.
2692                 */
2693                while (cursz >= splitsz) {
2694                        /* update the buddy's leaf with its new value.
2695                         */
2696                        dbAdjTree(tp, leafno ^ budsz, cursz);
2697
2698                        /* on to the next size and buddy.
2699                         */
2700                        cursz -= 1;
2701                        budsz >>= 1;
2702                }
2703        }
2704
2705        /* adjust the dmap tree to reflect the specified leaf's new
2706         * value.
2707         */
2708        dbAdjTree(tp, leafno, newval);
2709}
2710
2711
2712/*
2713 * NAME:        dbBackSplit()
2714 *
2715 * FUNCTION:    back split the binary buddy system of dmtree leaves
2716 *              that hold a specified leaf until the specified leaf
2717 *              starts its own binary buddy system.
2718 *
2719 *              the allocators typically perform allocations at the start
2720 *              of binary buddy systems and dbSplit() is used to accomplish
2721 *              any required splits.  in some cases, however, allocation
2722 *              may occur in the middle of a binary system and requires a
2723 *              back split, with the split proceeding out from the middle of
2724 *              the system (less efficient) rather than the start of the
2725 *              system (more efficient).  the cases in which a back split
2726 *              is required are rare and are limited to the first allocation
2727 *              within an allocation group which is a part (not first part)
2728 *              of a larger binary buddy system and a few exception cases
2729 *              in which a previous join operation must be backed out.
2730 *
2731 * PARAMETERS:
2732 *      tp      - pointer to the tree containing the leaf.
2733 *      leafno  - the number of the leaf to be updated.
2734 *
2735 * RETURN VALUES: none
2736 *
2737 * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
2738 */
2739static int dbBackSplit(dmtree_t * tp, int leafno)
2740{
2741        int budsz, bud, w, bsz, size;
2742        int cursz;
2743        s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2744
2745        /* leaf should be part (not first part) of a binary
2746         * buddy system.
2747         */
2748        assert(leaf[leafno] == NOFREE);
2749
2750        /* the back split is accomplished by iteratively finding the leaf
2751         * that starts the buddy system that contains the specified leaf and
2752         * splitting that system in two.  this iteration continues until
2753         * the specified leaf becomes the start of a buddy system.
2754         *
2755         * determine maximum possible l2 size for the specified leaf.
2756         */
2757        size =
2758            LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
2759                      tp->dmt_budmin);
2760
2761        /* determine the number of leaves covered by this size.  this
2762         * is the buddy size that we will start with as we search for
2763         * the buddy system that contains the specified leaf.
2764         */
2765        budsz = BUDSIZE(size, tp->dmt_budmin);
2766
2767        /* back split.
2768         */
2769        while (leaf[leafno] == NOFREE) {
2770                /* find the leftmost buddy leaf.
2771                 */
2772                for (w = leafno, bsz = budsz;; bsz <<= 1,
2773                     w = (w < bud) ? w : bud) {
2774                        if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
2775                                jfs_err("JFS: block map error in dbBackSplit");
2776                                return -EIO;
2777                        }
2778
2779                        /* determine the buddy.
2780                         */
2781                        bud = w ^ bsz;
2782
2783                        /* check if this buddy is the start of the system.
2784                         */
2785                        if (leaf[bud] != NOFREE) {
2786                                /* split the leaf at the start of the
2787                                 * system in two.
2788                                 */
2789                                cursz = leaf[bud] - 1;
2790                                dbSplit(tp, bud, cursz, cursz);
2791                                break;
2792                        }
2793                }
2794        }
2795
2796        if (leaf[leafno] != size) {
2797                jfs_err("JFS: wrong leaf value in dbBackSplit");
2798                return -EIO;
2799        }
2800        return 0;
2801}
2802
2803
2804/*
2805 * NAME:        dbJoin()
2806 *
2807 * FUNCTION:    update the leaf of a dmtree with a new value, joining
2808 *              the leaf with other leaves of the dmtree into a multi-leaf
2809 *              binary buddy system, as required.
2810 *
2811 * PARAMETERS:
2812 *      tp      - pointer to the tree containing the leaf.
2813 *      leafno  - the number of the leaf to be updated.
2814 *      newval  - the new value for the leaf.
2815 *
2816 * RETURN VALUES: none
2817 */
2818static int dbJoin(dmtree_t * tp, int leafno, int newval)
2819{
2820        int budsz, buddy;
2821        s8 *leaf;
2822
2823        /* can the new leaf value require a join with other leaves ?
2824         */
2825        if (newval >= tp->dmt_budmin) {
2826                /* pickup a pointer to the leaves of the tree.
2827                 */
2828                leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
2829
2830                /* try to join the specified leaf into a large binary
2831                 * buddy system.  the join proceeds by attempting to join
2832                 * the specified leafno with its buddy (leaf) at new value.
2833                 * if the join occurs, we attempt to join the left leaf
2834                 * of the joined buddies with its buddy at new value + 1.
2835                 * we continue to join until we find a buddy that cannot be
2836                 * joined (does not have a value equal to the size of the
2837                 * last join) or until all leaves have been joined into a
2838                 * single system.
2839                 *
2840                 * get the buddy size (number of words covered) of
2841                 * the new value.
2842                 */
2843                budsz = BUDSIZE(newval, tp->dmt_budmin);
2844
2845                /* try to join.
2846                 */
2847                while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
2848                        /* get the buddy leaf.
2849                         */
2850                        buddy = leafno ^ budsz;
2851
2852                        /* if the leaf's new value is greater than its
2853                         * buddy's value, we join no more.
2854                         */
2855                        if (newval > leaf[buddy])
2856                                break;
2857
2858                        /* It shouldn't be less */
2859                        if (newval < leaf[buddy])
2860                                return -EIO;
2861
2862                        /* check which (leafno or buddy) is the left buddy.
2863                         * the left buddy gets to claim the blocks resulting
2864                         * from the join while the right gets to claim none.
2865                         * the left buddy is also eligible to participate in
2866                         * a join at the next higher level while the right
2867                         * is not.
2868                         *
2869                         */
2870                        if (leafno < buddy) {
2871                                /* leafno is the left buddy.
2872                                 */
2873                                dbAdjTree(tp, buddy, NOFREE);
2874                        } else {
2875                                /* buddy is the left buddy and becomes
2876                                 * leafno.
2877                                 */
2878                                dbAdjTree(tp, leafno, NOFREE);
2879                                leafno = buddy;
2880                        }
2881
2882                        /* on to try the next join.
2883                         */
2884                        newval += 1;
2885                        budsz <<= 1;
2886                }
2887        }
2888
2889        /* update the leaf value.
2890         */
2891        dbAdjTree(tp, leafno, newval);
2892
2893        return 0;
2894}
2895
2896
2897/*
2898 * NAME:        dbAdjTree()
2899 *
2900 * FUNCTION:    update a leaf of a dmtree with a new value, adjusting
2901 *              the dmtree, as required, to reflect the new leaf value.
2902 *              the combination of any buddies must already be done before
2903 *              this is called.
2904 *
2905 * PARAMETERS:
2906 *      tp      - pointer to the tree to be adjusted.
2907 *      leafno  - the number of the leaf to be updated.
2908 *      newval  - the new value for the leaf.
2909 *
2910 * RETURN VALUES: none
2911 */
2912static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
2913{
2914        int lp, pp, k;
2915        int max;
2916
2917        /* pick up the index of the leaf for this leafno.
2918         */
2919        lp = leafno + le32_to_cpu(tp->dmt_leafidx);
2920
2921        /* is the current value the same as the old value ?  if so,
2922         * there is nothing to do.
2923         */
2924        if (tp->dmt_stree[lp] == newval)
2925                return;
2926
2927        /* set the new value.
2928         */
2929        tp->dmt_stree[lp] = newval;
2930
2931        /* bubble the new value up the tree as required.
2932         */
2933        for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
2934                /* get the index of the first leaf of the 4 leaf
2935                 * group containing the specified leaf (leafno).
2936                 */
2937                lp = ((lp - 1) & ~0x03) + 1;
2938
2939                /* get the index of the parent of this 4 leaf group.
2940                 */
2941                pp = (lp - 1) >> 2;
2942
2943                /* determine the maximum of the 4 leaves.
2944                 */
2945                max = TREEMAX(&tp->dmt_stree[lp]);
2946
2947                /* if the maximum of the 4 is the same as the
2948                 * parent's value, we're done.
2949                 */
2950                if (tp->dmt_stree[pp] == max)
2951                        break;
2952
2953                /* parent gets new value.
2954                 */
2955                tp->dmt_stree[pp] = max;
2956
2957                /* parent becomes leaf for next go-round.
2958                 */
2959                lp = pp;
2960        }
2961}
2962
2963
2964/*
2965 * NAME:        dbFindLeaf()
2966 *
2967 * FUNCTION:    search a dmtree_t for sufficient free blocks, returning
2968 *              the index of a leaf describing the free blocks if
2969 *              sufficient free blocks are found.
2970 *
2971 *              the search starts at the top of the dmtree_t tree and
2972 *              proceeds down the tree to the leftmost leaf with sufficient
2973 *              free space.
2974 *
2975 * PARAMETERS:
2976 *      tp      - pointer to the tree to be searched.
2977 *      l2nb    - log2 number of free blocks to search for.
2978 *      leafidx - return pointer to be set to the index of the leaf
2979 *                describing at least l2nb free blocks if sufficient
2980 *                free blocks are found.
2981 *
2982 * RETURN VALUES:
2983 *      0       - success
2984 *      -ENOSPC - insufficient free blocks.
2985 */
2986static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
2987{
2988        int ti, n = 0, k, x = 0;
2989
2990        /* first check the root of the tree to see if there is
2991         * sufficient free space.
2992         */
2993        if (l2nb > tp->dmt_stree[ROOT])
2994                return -ENOSPC;
2995
2996        /* sufficient free space available. now search down the tree
2997         * starting at the next level for the leftmost leaf that
2998         * describes sufficient free space.
2999         */
3000        for (k = le32_to_cpu(tp->dmt_height), ti = 1;
3001             k > 0; k--, ti = ((ti + n) << 2) + 1) {
3002                /* search the four nodes at this level, starting from
3003                 * the left.
3004                 */
3005                for (x = ti, n = 0; n < 4; n++) {
3006                        /* sufficient free space found.  move to the next
3007                         * level (or quit if this is the last level).
3008                         */
3009                        if (l2nb <= tp->dmt_stree[x + n])
3010                                break;
3011                }
3012
3013                /* better have found something since the higher
3014                 * levels of the tree said it was here.
3015                 */
3016                assert(n < 4);
3017        }
3018
3019        /* set the return to the leftmost leaf describing sufficient
3020         * free space.
3021         */
3022        *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
3023
3024        return (0);
3025}
3026
3027
3028/*
3029 * NAME:        dbFindBits()
3030 *
3031 * FUNCTION:    find a specified number of binary buddy free bits within a
3032 *              dmap bitmap word value.
3033 *
3034 *              this routine searches the bitmap value for (1 << l2nb) free
3035 *              bits at (1 << l2nb) alignments within the value.
3036 *
3037 * PARAMETERS:
3038 *      word    -  dmap bitmap word value.
3039 *      l2nb    -  number of free bits specified as a log2 number.
3040 *
3041 * RETURN VALUES:
3042 *      starting bit number of free bits.
3043 */
3044static int dbFindBits(u32 word, int l2nb)
3045{
3046        int bitno, nb;
3047        u32 mask;
3048
3049        /* get the number of bits.
3050         */
3051        nb = 1 << l2nb;
3052        assert(nb <= DBWORD);
3053
3054        /* complement the word so we can use a mask (i.e. 0s represent
3055         * free bits) and compute the mask.
3056         */
3057        word = ~word;
3058        mask = ONES << (DBWORD - nb);
3059
3060        /* scan the word for nb free bits at nb alignments.
3061         */
3062        for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
3063                if ((mask & word) == mask)
3064                        break;
3065        }
3066
3067        ASSERT(bitno < 32);
3068
3069        /* return the bit number.
3070         */
3071        return (bitno);
3072}
3073
3074
3075/*
3076 * NAME:        dbMaxBud(u8 *cp)
3077 *
3078 * FUNCTION:    determine the largest binary buddy string of free
3079 *              bits within 32-bits of the map.
3080 *
3081 * PARAMETERS:
3082 *      cp      -  pointer to the 32-bit value.
3083 *
3084 * RETURN VALUES:
3085 *      largest binary buddy of free bits within a dmap word.
3086 */
3087static int dbMaxBud(u8 * cp)
3088{
3089        signed char tmp1, tmp2;
3090
3091        /* check if the wmap word is all free. if so, the
3092         * free buddy size is BUDMIN.
3093         */
3094        if (*((uint *) cp) == 0)
3095                return (BUDMIN);
3096
3097        /* check if the wmap word is half free. if so, the
3098         * free buddy size is BUDMIN-1.
3099         */
3100        if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
3101                return (BUDMIN - 1);
3102
3103        /* not all free or half free. determine the free buddy
3104         * size thru table lookup using quarters of the wmap word.
3105         */
3106        tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
3107        tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
3108        return (max(tmp1, tmp2));
3109}
3110
3111
3112/*
3113 * NAME:        cnttz(uint word)
3114 *
3115 * FUNCTION:    determine the number of trailing zeros within a 32-bit
3116 *              value.
3117 *
3118 * PARAMETERS:
3119 *      value   -  32-bit value to be examined.
3120 *
3121 * RETURN VALUES:
3122 *      count of trailing zeros
3123 */
3124static int cnttz(u32 word)
3125{
3126        int n;
3127
3128        for (n = 0; n < 32; n++, word >>= 1) {
3129                if (word & 0x01)
3130                        break;
3131        }
3132
3133        return (n);
3134}
3135
3136
3137/*
3138 * NAME:        cntlz(u32 value)
3139 *
3140 * FUNCTION:    determine the number of leading zeros within a 32-bit
3141 *              value.
3142 *
3143 * PARAMETERS:
3144 *      value   -  32-bit value to be examined.
3145 *
3146 * RETURN VALUES:
3147 *      count of leading zeros
3148 */
3149static int cntlz(u32 value)
3150{
3151        int n;
3152
3153        for (n = 0; n < 32; n++, value <<= 1) {
3154                if (value & HIGHORDER)
3155                        break;
3156        }
3157        return (n);
3158}
3159
3160
3161/*
3162 * NAME:        blkstol2(s64 nb)
3163 *
3164 * FUNCTION:    convert a block count to its log2 value. if the block
3165 *              count is not a l2 multiple, it is rounded up to the next
3166 *              larger l2 multiple.
3167 *
3168 * PARAMETERS:
3169 *      nb      -  number of blocks
3170 *
3171 * RETURN VALUES:
3172 *      log2 number of blocks
3173 */
3174static int blkstol2(s64 nb)
3175{
3176        int l2nb;
3177        s64 mask;               /* meant to be signed */
3178
3179        mask = (s64) 1 << (64 - 1);
3180
3181        /* count the leading bits.
3182         */
3183        for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
3184                /* leading bit found.
3185                 */
3186                if (nb & mask) {
3187                        /* determine the l2 value.
3188                         */
3189                        l2nb = (64 - 1) - l2nb;
3190
3191                        /* check if we need to round up.
3192                         */
3193                        if (~mask & nb)
3194                                l2nb++;
3195
3196                        return (l2nb);
3197                }
3198        }
3199        assert(0);
3200        return 0;               /* fix compiler warning */
3201}
3202
3203
3204/*
3205 * NAME:        dbAllocBottomUp()
3206 *
3207 * FUNCTION:    alloc the specified block range from the working block
3208 *              allocation map.
3209 *
3210 *              the blocks will be alloc from the working map one dmap
3211 *              at a time.
3212 *
3213 * PARAMETERS:
3214 *      ip      -  pointer to in-core inode;
3215 *      blkno   -  starting block number to be freed.
3216 *      nblocks -  number of blocks to be freed.
3217 *
3218 * RETURN VALUES:
3219 *      0       - success
3220 *      -EIO    - i/o error
3221 */
3222int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
3223{
3224        struct metapage *mp;
3225        struct dmap *dp;
3226        int nb, rc;
3227        s64 lblkno, rem;
3228        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
3229        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
3230
3231        IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
3232
3233        /* block to be allocated better be within the mapsize. */
3234        ASSERT(nblocks <= bmp->db_mapsize - blkno);
3235
3236        /*
3237         * allocate the blocks a dmap at a time.
3238         */
3239        mp = NULL;
3240        for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
3241                /* release previous dmap if any */
3242                if (mp) {
3243                        write_metapage(mp);
3244                }
3245
3246                /* get the buffer for the current dmap. */
3247                lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
3248                mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
3249                if (mp == NULL) {
3250                        IREAD_UNLOCK(ipbmap);
3251                        return -EIO;
3252                }
3253                dp = (struct dmap *) mp->data;
3254
3255                /* determine the number of blocks to be allocated from
3256                 * this dmap.
3257                 */
3258                nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
3259
3260                /* allocate the blocks. */
3261                if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
3262                        release_metapage(mp);
3263                        IREAD_UNLOCK(ipbmap);
3264                        return (rc);
3265                }
3266        }
3267
3268        /* write the last buffer. */
3269        write_metapage(mp);
3270
3271        IREAD_UNLOCK(ipbmap);
3272
3273        return (0);
3274}
3275
3276
3277static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
3278                         int nblocks)
3279{
3280        int rc;
3281        int dbitno, word, rembits, nb, nwords, wbitno, agno;
3282        s8 oldroot;
3283        struct dmaptree *tp = (struct dmaptree *) & dp->tree;
3284
3285        /* save the current value of the root (i.e. maximum free string)
3286         * of the dmap tree.
3287         */
3288        oldroot = tp->stree[ROOT];
3289
3290        /* determine the bit number and word within the dmap of the
3291         * starting block.
3292         */
3293        dbitno = blkno & (BPERDMAP - 1);
3294        word = dbitno >> L2DBWORD;
3295
3296        /* block range better be within the dmap */
3297        assert(dbitno + nblocks <= BPERDMAP);
3298
3299        /* allocate the bits of the dmap's words corresponding to the block
3300         * range. not all bits of the first and last words may be contained
3301         * within the block range.  if this is the case, we'll work against
3302         * those words (i.e. partial first and/or last) on an individual basis
3303         * (a single pass), allocating the bits of interest by hand and
3304         * updating the leaf corresponding to the dmap word. a single pass
3305         * will be used for all dmap words fully contained within the
3306         * specified range.  within this pass, the bits of all fully contained
3307         * dmap words will be marked as free in a single shot and the leaves
3308         * will be updated. a single leaf may describe the free space of
3309         * multiple dmap words, so we may update only a subset of the actual
3310         * leaves corresponding to the dmap words of the block range.
3311         */
3312        for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
3313                /* determine the bit number within the word and
3314                 * the number of bits within the word.
3315                 */
3316                wbitno = dbitno & (DBWORD - 1);
3317                nb = min(rembits, DBWORD - wbitno);
3318
3319                /* check if only part of a word is to be allocated.
3320                 */
3321                if (nb < DBWORD) {
3322                        /* allocate (set to 1) the appropriate bits within
3323                         * this dmap word.
3324                         */
3325                        dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
3326                                                      >> wbitno);
3327
3328                        word++;
3329                } else {
3330                        /* one or more dmap words are fully contained
3331                         * within the block range.  determine how many
3332                         * words and allocate (set to 1) the bits of these
3333                         * words.
3334                         */
3335                        nwords = rembits >> L2DBWORD;
3336                        memset(&dp->wmap[word], (int) ONES, nwords * 4);
3337
3338                        /* determine how many bits */
3339                        nb = nwords << L2DBWORD;
3340                        word += nwords;
3341                }
3342        }
3343
3344        /* update the free count for this dmap */
3345        le32_add_cpu(&dp->nfree, -nblocks);
3346
3347        /* reconstruct summary tree */
3348        dbInitDmapTree(dp);
3349
3350        BMAP_LOCK(bmp);
3351
3352        /* if this allocation group is completely free,
3353         * update the highest active allocation group number
3354         * if this allocation group is the new max.
3355         */
3356        agno = blkno >> bmp->db_agl2size;
3357        if (agno > bmp->db_maxag)
3358                bmp->db_maxag = agno;
3359
3360        /* update the free count for the allocation group and map */
3361        bmp->db_agfree[agno] -= nblocks;
3362        bmp->db_nfree -= nblocks;
3363
3364        BMAP_UNLOCK(bmp);
3365
3366        /* if the root has not changed, done. */
3367        if (tp->stree[ROOT] == oldroot)
3368                return (0);
3369
3370        /* root changed. bubble the change up to the dmap control pages.
3371         * if the adjustment of the upper level control pages fails,
3372         * backout the bit allocation (thus making everything consistent).
3373         */
3374        if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
3375                dbFreeBits(bmp, dp, blkno, nblocks);
3376
3377        return (rc);
3378}
3379
3380
3381/*
3382 * NAME:        dbExtendFS()
3383 *
3384 * FUNCTION:    extend bmap from blkno for nblocks;
3385 *              dbExtendFS() updates bmap ready for dbAllocBottomUp();
3386 *
3387 * L2
3388 *  |
3389 *   L1---------------------------------L1
3390 *    |                                  |
3391 *     L0---------L0---------L0           L0---------L0---------L0
3392 *      |          |          |            |          |          |
3393 *       d0,...,dn  d0,...,dn  d0,...,dn    d0,...,dn  d0,...,dn  d0,.,dm;
3394 * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
3395 *
3396 * <---old---><----------------------------extend----------------------->
3397 */
3398int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
3399{
3400        struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
3401        int nbperpage = sbi->nbperpage;
3402        int i, i0 = true, j, j0 = true, k, n;
3403        s64 newsize;
3404        s64 p;
3405        struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
3406        struct dmapctl *l2dcp, *l1dcp, *l0dcp;
3407        struct dmap *dp;
3408        s8 *l0leaf, *l1leaf, *l2leaf;
3409        struct bmap *bmp = sbi->bmap;
3410        int agno, l2agsize, oldl2agsize;
3411        s64 ag_rem;
3412
3413        newsize = blkno + nblocks;
3414
3415        jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
3416                 (long long) blkno, (long long) nblocks, (long long) newsize);
3417
3418        /*
3419         *      initialize bmap control page.
3420         *
3421         * all the data in bmap control page should exclude
3422         * the mkfs hidden dmap page.
3423         */
3424
3425        /* update mapsize */
3426        bmp->db_mapsize = newsize;
3427        bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
3428
3429        /* compute new AG size */
3430        l2agsize = dbGetL2AGSize(newsize);
3431        oldl2agsize = bmp->db_agl2size;
3432
3433        bmp->db_agl2size = l2agsize;
3434        bmp->db_agsize = 1 << l2agsize;
3435
3436        /* compute new number of AG */
3437        agno = bmp->db_numag;
3438        bmp->db_numag = newsize >> l2agsize;
3439        bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
3440
3441        /*
3442         *      reconfigure db_agfree[]
3443         * from old AG configuration to new AG configuration;
3444         *
3445         * coalesce contiguous k (newAGSize/oldAGSize) AGs;
3446         * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
3447         * note: new AG size = old AG size * (2**x).
3448         */
3449        if (l2agsize == oldl2agsize)
3450                goto extend;
3451        k = 1 << (l2agsize - oldl2agsize);
3452        ag_rem = bmp->db_agfree[0];     /* save agfree[0] */
3453        for (i = 0, n = 0; i < agno; n++) {
3454                bmp->db_agfree[n] = 0;  /* init collection point */
3455
3456                /* coalesce contiguous k AGs; */
3457                for (j = 0; j < k && i < agno; j++, i++) {
3458                        /* merge AGi to AGn */
3459                        bmp->db_agfree[n] += bmp->db_agfree[i];
3460                }
3461        }
3462        bmp->db_agfree[0] += ag_rem;    /* restore agfree[0] */
3463
3464        for (; n < MAXAG; n++)
3465                bmp->db_agfree[n] = 0;
3466
3467        /*
3468         * update highest active ag number
3469         */
3470
3471        bmp->db_maxag = bmp->db_maxag / k;
3472
3473        /*
3474         *      extend bmap
3475         *
3476         * update bit maps and corresponding level control pages;
3477         * global control page db_nfree, db_agfree[agno], db_maxfreebud;
3478         */
3479      extend:
3480        /* get L2 page */
3481        p = BMAPBLKNO + nbperpage;      /* L2 page */
3482        l2mp = read_metapage(ipbmap, p, PSIZE, 0);
3483        if (!l2mp) {
3484                jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
3485                return -EIO;
3486        }
3487        l2dcp = (struct dmapctl *) l2mp->data;
3488
3489        /* compute start L1 */
3490        k = blkno >> L2MAXL1SIZE;
3491        l2leaf = l2dcp->stree + CTLLEAFIND + k;
3492        p = BLKTOL1(blkno, sbi->l2nbperpage);   /* L1 page */
3493
3494        /*
3495         * extend each L1 in L2
3496         */
3497        for (; k < LPERCTL; k++, p += nbperpage) {
3498                /* get L1 page */
3499                if (j0) {
3500                        /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
3501                        l1mp = read_metapage(ipbmap, p, PSIZE, 0);
3502                        if (l1mp == NULL)
3503                                goto errout;
3504                        l1dcp = (struct dmapctl *) l1mp->data;
3505
3506                        /* compute start L0 */
3507                        j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
3508                        l1leaf = l1dcp->stree + CTLLEAFIND + j;
3509                        p = BLKTOL0(blkno, sbi->l2nbperpage);
3510                        j0 = false;
3511                } else {
3512                        /* assign/init L1 page */
3513                        l1mp = get_metapage(ipbmap, p, PSIZE, 0);
3514                        if (l1mp == NULL)
3515                                goto errout;
3516
3517                        l1dcp = (struct dmapctl *) l1mp->data;
3518
3519                        /* compute start L0 */
3520                        j = 0;
3521                        l1leaf = l1dcp->stree + CTLLEAFIND;
3522                        p += nbperpage; /* 1st L0 of L1.k */
3523                }
3524
3525                /*
3526                 * extend each L0 in L1
3527                 */
3528                for (; j < LPERCTL; j++) {
3529                        /* get L0 page */
3530                        if (i0) {
3531                                /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
3532
3533                                l0mp = read_metapage(ipbmap, p, PSIZE, 0);
3534                                if (l0mp == NULL)
3535                                        goto errout;
3536                                l0dcp = (struct dmapctl *) l0mp->data;
3537
3538                                /* compute start dmap */
3539                                i = (blkno & (MAXL0SIZE - 1)) >>
3540                                    L2BPERDMAP;
3541                                l0leaf = l0dcp->stree + CTLLEAFIND + i;
3542                                p = BLKTODMAP(blkno,
3543                                              sbi->l2nbperpage);
3544                                i0 = false;
3545                        } else {
3546                                /* assign/init L0 page */
3547                                l0mp = get_metapage(ipbmap, p, PSIZE, 0);
3548                                if (l0mp == NULL)
3549                                        goto errout;
3550
3551                                l0dcp = (struct dmapctl *) l0mp->data;
3552
3553                                /* compute start dmap */
3554                                i = 0;
3555                                l0leaf = l0dcp->stree + CTLLEAFIND;
3556                                p += nbperpage; /* 1st dmap of L0.j */
3557                        }
3558
3559                        /*
3560                         * extend each dmap in L0
3561                         */
3562                        for (; i < LPERCTL; i++) {
3563                                /*
3564                                 * reconstruct the dmap page, and
3565                                 * initialize corresponding parent L0 leaf
3566                                 */
3567                                if ((n = blkno & (BPERDMAP - 1))) {
3568                                        /* read in dmap page: */
3569                                        mp = read_metapage(ipbmap, p,
3570                                                           PSIZE, 0);
3571                                        if (mp == NULL)
3572                                                goto errout;
3573                                        n = min(nblocks, (s64)BPERDMAP - n);
3574                                } else {
3575                                        /* assign/init dmap page */
3576                                        mp = read_metapage(ipbmap, p,
3577                                                           PSIZE, 0);
3578                                        if (mp == NULL)
3579                                                goto errout;
3580
3581                                        n = min(nblocks, (s64)BPERDMAP);
3582                                }
3583
3584                                dp = (struct dmap *) mp->data;
3585                                *l0leaf = dbInitDmap(dp, blkno, n);
3586
3587                                bmp->db_nfree += n;
3588                                agno = le64_to_cpu(dp->start) >> l2agsize;
3589                                bmp->db_agfree[agno] += n;
3590
3591                                write_metapage(mp);
3592
3593                                l0leaf++;
3594                                p += nbperpage;
3595
3596                                blkno += n;
3597                                nblocks -= n;
3598                                if (nblocks == 0)
3599                                        break;
3600                        }       /* for each dmap in a L0 */
3601
3602                        /*
3603                         * build current L0 page from its leaves, and
3604                         * initialize corresponding parent L1 leaf
3605                         */
3606                        *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
3607                        write_metapage(l0mp);
3608                        l0mp = NULL;
3609
3610                        if (nblocks)
3611                                l1leaf++;       /* continue for next L0 */
3612                        else {
3613                                /* more than 1 L0 ? */
3614                                if (j > 0)
3615                                        break;  /* build L1 page */
3616                                else {
3617                                        /* summarize in global bmap page */
3618                                        bmp->db_maxfreebud = *l1leaf;
3619                                        release_metapage(l1mp);
3620                                        release_metapage(l2mp);
3621                                        goto finalize;
3622                                }
3623                        }
3624                }               /* for each L0 in a L1 */
3625
3626                /*
3627                 * build current L1 page from its leaves, and
3628                 * initialize corresponding parent L2 leaf
3629                 */
3630                *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
3631                write_metapage(l1mp);
3632                l1mp = NULL;
3633
3634                if (nblocks)
3635                        l2leaf++;       /* continue for next L1 */
3636                else {
3637                        /* more than 1 L1 ? */
3638                        if (k > 0)
3639                                break;  /* build L2 page */
3640                        else {
3641                                /* summarize in global bmap page */
3642                                bmp->db_maxfreebud = *l2leaf;
3643                                release_metapage(l2mp);
3644                                goto finalize;
3645                        }
3646                }
3647        }                       /* for each L1 in a L2 */
3648
3649        jfs_error(ipbmap->i_sb,
3650                  "dbExtendFS: function has not returned as expected");
3651errout:
3652        if (l0mp)
3653                release_metapage(l0mp);
3654        if (l1mp)
3655                release_metapage(l1mp);
3656        release_metapage(l2mp);
3657        return -EIO;
3658
3659        /*
3660         *      finalize bmap control page
3661         */
3662finalize:
3663
3664        return 0;
3665}
3666
3667
3668/*
3669 *      dbFinalizeBmap()
3670 */
3671void dbFinalizeBmap(struct inode *ipbmap)
3672{
3673        struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
3674        int actags, inactags, l2nl;
3675        s64 ag_rem, actfree, inactfree, avgfree;
3676        int i, n;
3677
3678        /*
3679         *      finalize bmap control page
3680         */
3681//finalize:
3682        /*
3683         * compute db_agpref: preferred ag to allocate from
3684         * (the leftmost ag with average free space in it);
3685         */
3686//agpref:
3687        /* get the number of active ags and inacitve ags */
3688        actags = bmp->db_maxag + 1;
3689        inactags = bmp->db_numag - actags;
3690        ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1);        /* ??? */
3691
3692        /* determine how many blocks are in the inactive allocation
3693         * groups. in doing this, we must account for the fact that
3694         * the rightmost group might be a partial group (i.e. file
3695         * system size is not a multiple of the group size).
3696         */
3697        inactfree = (inactags && ag_rem) ?
3698            ((inactags - 1) << bmp->db_agl2size) + ag_rem
3699            : inactags << bmp->db_agl2size;
3700
3701        /* determine how many free blocks are in the active
3702         * allocation groups plus the average number of free blocks
3703         * within the active ags.
3704         */
3705        actfree = bmp->db_nfree - inactfree;
3706        avgfree = (u32) actfree / (u32) actags;
3707
3708        /* if the preferred allocation group has not average free space.
3709         * re-establish the preferred group as the leftmost
3710         * group with average free space.
3711         */
3712        if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
3713                for (bmp->db_agpref = 0; bmp->db_agpref < actags;
3714                     bmp->db_agpref++) {
3715                        if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
3716                                break;
3717                }
3718                if (bmp->db_agpref >= bmp->db_numag) {
3719                        jfs_error(ipbmap->i_sb,
3720                                  "cannot find ag with average freespace");
3721                }
3722        }
3723
3724        /*
3725         * compute db_aglevel, db_agheight, db_width, db_agstart:
3726         * an ag is covered in aglevel dmapctl summary tree,
3727         * at agheight level height (from leaf) with agwidth number of nodes
3728         * each, which starts at agstart index node of the smmary tree node
3729         * array;
3730         */
3731        bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
3732        l2nl =
3733            bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
3734        bmp->db_agheight = l2nl >> 1;
3735        bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
3736        for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
3737             i--) {
3738                bmp->db_agstart += n;
3739                n <<= 2;
3740        }
3741
3742}
3743
3744
3745/*
3746 * NAME:        dbInitDmap()/ujfs_idmap_page()
3747 *
3748 * FUNCTION:    initialize working/persistent bitmap of the dmap page
3749 *              for the specified number of blocks:
3750 *
3751 *              at entry, the bitmaps had been initialized as free (ZEROS);
3752 *              The number of blocks will only account for the actually
3753 *              existing blocks. Blocks which don't actually exist in
3754 *              the aggregate will be marked as allocated (ONES);
3755 *
3756 * PARAMETERS:
3757 *      dp      - pointer to page of map
3758 *      nblocks - number of blocks this page
3759 *
3760 * RETURNS: NONE
3761 */
3762static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
3763{
3764        int blkno, w, b, r, nw, nb, i;
3765
3766        /* starting block number within the dmap */
3767        blkno = Blkno & (BPERDMAP - 1);
3768
3769        if (blkno == 0) {
3770                dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
3771                dp->start = cpu_to_le64(Blkno);
3772
3773                if (nblocks == BPERDMAP) {
3774                        memset(&dp->wmap[0], 0, LPERDMAP * 4);
3775                        memset(&dp->pmap[0], 0, LPERDMAP * 4);
3776                        goto initTree;
3777                }
3778        } else {
3779                le32_add_cpu(&dp->nblocks, nblocks);
3780                le32_add_cpu(&dp->nfree, nblocks);
3781        }
3782
3783        /* word number containing start block number */
3784        w = blkno >> L2DBWORD;
3785
3786        /*
3787         * free the bits corresponding to the block range (ZEROS):
3788         * note: not all bits of the first and last words may be contained
3789         * within the block range.
3790         */
3791        for (r = nblocks; r > 0; r -= nb, blkno += nb) {
3792                /* number of bits preceding range to be freed in the word */
3793                b = blkno & (DBWORD - 1);
3794                /* number of bits to free in the word */
3795                nb = min(r, DBWORD - b);
3796
3797                /* is partial word to be freed ? */
3798                if (nb < DBWORD) {
3799                        /* free (set to 0) from the bitmap word */
3800                        dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3801                                                     >> b));
3802                        dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
3803                                                     >> b));
3804
3805                        /* skip the word freed */
3806                        w++;
3807                } else {
3808                        /* free (set to 0) contiguous bitmap words */
3809                        nw = r >> L2DBWORD;
3810                        memset(&dp->wmap[w], 0, nw * 4);
3811                        memset(&dp->pmap[w], 0, nw * 4);
3812
3813                        /* skip the words freed */
3814                        nb = nw << L2DBWORD;
3815                        w += nw;
3816                }
3817        }
3818
3819        /*
3820         * mark bits following the range to be freed (non-existing
3821         * blocks) as allocated (ONES)
3822         */
3823
3824        if (blkno == BPERDMAP)
3825                goto initTree;
3826
3827        /* the first word beyond the end of existing blocks */
3828        w = blkno >> L2DBWORD;
3829
3830        /* does nblocks fall on a 32-bit boundary ? */
3831        b = blkno & (DBWORD - 1);
3832        if (b) {
3833                /* mark a partial word allocated */
3834                dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
3835                w++;
3836        }
3837
3838        /* set the rest of the words in the page to allocated (ONES) */
3839        for (i = w; i < LPERDMAP; i++)
3840                dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
3841
3842        /*
3843         * init tree
3844         */
3845      initTree:
3846        return (dbInitDmapTree(dp));
3847}
3848
3849
3850/*
3851 * NAME:        dbInitDmapTree()/ujfs_complete_dmap()
3852 *
3853 * FUNCTION:    initialize summary tree of the specified dmap:
3854 *
3855 *              at entry, bitmap of the dmap has been initialized;
3856 *
3857 * PARAMETERS:
3858 *      dp      - dmap to complete
3859 *      blkno   - starting block number for this dmap
3860 *      treemax - will be filled in with max free for this dmap
3861 *
3862 * RETURNS:     max free string at the root of the tree
3863 */
3864static int dbInitDmapTree(struct dmap * dp)
3865{
3866        struct dmaptree *tp;
3867        s8 *cp;
3868        int i;
3869
3870        /* init fixed info of tree */
3871        tp = &dp->tree;
3872        tp->nleafs = cpu_to_le32(LPERDMAP);
3873        tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
3874        tp->leafidx = cpu_to_le32(LEAFIND);
3875        tp->height = cpu_to_le32(4);
3876        tp->budmin = BUDMIN;
3877
3878        /* init each leaf from corresponding wmap word:
3879         * note: leaf is set to NOFREE(-1) if all blocks of corresponding
3880         * bitmap word are allocated.
3881         */
3882        cp = tp->stree + le32_to_cpu(tp->leafidx);
3883        for (i = 0; i < LPERDMAP; i++)
3884                *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
3885
3886        /* build the dmap's binary buddy summary tree */
3887        return (dbInitTree(tp));
3888}
3889
3890
3891/*
3892 * NAME:        dbInitTree()/ujfs_adjtree()
3893 *
3894 * FUNCTION:    initialize binary buddy summary tree of a dmap or dmapctl.
3895 *
3896 *              at entry, the leaves of the tree has been initialized
3897 *              from corresponding bitmap word or root of summary tree
3898 *              of the child control page;
3899 *              configure binary buddy system at the leaf level, then
3900 *              bubble up the values of the leaf nodes up the tree.
3901 *
3902 * PARAMETERS:
3903 *      cp      - Pointer to the root of the tree
3904 *      l2leaves- Number of leaf nodes as a power of 2
3905 *      l2min   - Number of blocks that can be covered by a leaf
3906 *                as a power of 2
3907 *
3908 * RETURNS: max free string at the root of the tree
3909 */
3910static int dbInitTree(struct dmaptree * dtp)
3911{
3912        int l2max, l2free, bsize, nextb, i;
3913        int child, parent, nparent;
3914        s8 *tp, *cp, *cp1;
3915
3916        tp = dtp->stree;
3917
3918        /* Determine the maximum free string possible for the leaves */
3919        l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
3920
3921        /*
3922         * configure the leaf levevl into binary buddy system
3923         *
3924         * Try to combine buddies starting with a buddy size of 1
3925         * (i.e. two leaves). At a buddy size of 1 two buddy leaves
3926         * can be combined if both buddies have a maximum free of l2min;
3927         * the combination will result in the left-most buddy leaf having
3928         * a maximum free of l2min+1.
3929         * After processing all buddies for a given size, process buddies
3930         * at the next higher buddy size (i.e. current size * 2) and
3931         * the next maximum free (current free + 1).
3932         * This continues until the maximum possible buddy combination
3933         * yields maximum free.
3934         */
3935        for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
3936             l2free++, bsize = nextb) {
3937                /* get next buddy size == current buddy pair size */
3938                nextb = bsize << 1;
3939
3940                /* scan each adjacent buddy pair at current buddy size */
3941                for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
3942                     i < le32_to_cpu(dtp->nleafs);
3943                     i += nextb, cp += nextb) {
3944                        /* coalesce if both adjacent buddies are max free */
3945                        if (*cp == l2free && *(cp + bsize) == l2free) {
3946                                *cp = l2free + 1;       /* left take right */
3947                                *(cp + bsize) = -1;     /* right give left */
3948                        }
3949                }
3950        }
3951
3952        /*
3953         * bubble summary information of leaves up the tree.
3954         *
3955         * Starting at the leaf node level, the four nodes described by
3956         * the higher level parent node are compared for a maximum free and
3957         * this maximum becomes the value of the parent node.
3958         * when all lower level nodes are processed in this fashion then
3959         * move up to the next level (parent becomes a lower level node) and
3960         * continue the process for that level.
3961         */
3962        for (child = le32_to_cpu(dtp->leafidx),
3963             nparent = le32_to_cpu(dtp->nleafs) >> 2;
3964             nparent > 0; nparent >>= 2, child = parent) {
3965                /* get index of 1st node of parent level */
3966                parent = (child - 1) >> 2;
3967
3968                /* set the value of the parent node as the maximum
3969                 * of the four nodes of the current level.
3970                 */
3971                for (i = 0, cp = tp + child, cp1 = tp + parent;
3972                     i < nparent; i++, cp += 4, cp1++)
3973                        *cp1 = TREEMAX(cp);
3974        }
3975
3976        return (*tp);
3977}
3978
3979
3980/*
3981 *      dbInitDmapCtl()
3982 *
3983 * function: initialize dmapctl page
3984 */
3985static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
3986{                               /* start leaf index not covered by range */
3987        s8 *cp;
3988
3989        dcp->nleafs = cpu_to_le32(LPERCTL);
3990        dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
3991        dcp->leafidx = cpu_to_le32(CTLLEAFIND);
3992        dcp->height = cpu_to_le32(5);
3993        dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
3994
3995        /*
3996         * initialize the leaves of current level that were not covered
3997         * by the specified input block range (i.e. the leaves have no
3998         * low level dmapctl or dmap).
3999         */
4000        cp = &dcp->stree[CTLLEAFIND + i];
4001        for (; i < LPERCTL; i++)
4002                *cp++ = NOFREE;
4003
4004        /* build the dmap's binary buddy summary tree */
4005        return (dbInitTree((struct dmaptree *) dcp));
4006}
4007
4008
4009/*
4010 * NAME:        dbGetL2AGSize()/ujfs_getagl2size()
4011 *
4012 * FUNCTION:    Determine log2(allocation group size) from aggregate size
4013 *
4014 * PARAMETERS:
4015 *      nblocks - Number of blocks in aggregate
4016 *
4017 * RETURNS: log2(allocation group size) in aggregate blocks
4018 */
4019static int dbGetL2AGSize(s64 nblocks)
4020{
4021        s64 sz;
4022        s64 m;
4023        int l2sz;
4024
4025        if (nblocks < BPERDMAP * MAXAG)
4026                return (L2BPERDMAP);
4027
4028        /* round up aggregate size to power of 2 */
4029        m = ((u64) 1 << (64 - 1));
4030        for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
4031                if (m & nblocks)
4032                        break;
4033        }
4034
4035        sz = (s64) 1 << l2sz;
4036        if (sz < nblocks)
4037                l2sz += 1;
4038
4039        /* agsize = roundupSize/max_number_of_ag */
4040        return (l2sz - L2MAXAG);
4041}
4042
4043
4044/*
4045 * NAME:        dbMapFileSizeToMapSize()
4046 *
4047 * FUNCTION:    compute number of blocks the block allocation map file
4048 *              can cover from the map file size;
4049 *
4050 * RETURNS:     Number of blocks which can be covered by this block map file;
4051 */
4052
4053/*
4054 * maximum number of map pages at each level including control pages
4055 */
4056#define MAXL0PAGES      (1 + LPERCTL)
4057#define MAXL1PAGES      (1 + LPERCTL * MAXL0PAGES)
4058#define MAXL2PAGES      (1 + LPERCTL * MAXL1PAGES)
4059
4060/*
4061 * convert number of map pages to the zero origin top dmapctl level
4062 */
4063#define BMAPPGTOLEV(npages)     \
4064        (((npages) <= 3 + MAXL0PAGES) ? 0 : \
4065         ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
4066
4067s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
4068{
4069        struct super_block *sb = ipbmap->i_sb;
4070        s64 nblocks;
4071        s64 npages, ndmaps;
4072        int level, i;
4073        int complete, factor;
4074
4075        nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
4076        npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
4077        level = BMAPPGTOLEV(npages);
4078
4079        /* At each level, accumulate the number of dmap pages covered by
4080         * the number of full child levels below it;
4081         * repeat for the last incomplete child level.
4082         */
4083        ndmaps = 0;
4084        npages--;               /* skip the first global control page */
4085        /* skip higher level control pages above top level covered by map */
4086        npages -= (2 - level);
4087        npages--;               /* skip top level's control page */
4088        for (i = level; i >= 0; i--) {
4089                factor =
4090                    (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
4091                complete = (u32) npages / factor;
4092                ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
4093                                      ((i == 1) ? LPERCTL : 1));
4094
4095                /* pages in last/incomplete child */
4096                npages = (u32) npages % factor;
4097                /* skip incomplete child's level control page */
4098                npages--;
4099        }
4100
4101        /* convert the number of dmaps into the number of blocks
4102         * which can be covered by the dmaps;
4103         */
4104        nblocks = ndmaps << L2BPERDMAP;
4105
4106        return (nblocks);
4107}
4108
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