fs/xfs/xfs_rtalloc.c

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_shared.h"
  21 #include "xfs_format.h"
  22 #include "xfs_log_format.h"
  23 #include "xfs_trans_resv.h"
  24 #include "xfs_bit.h"
  25 #include "xfs_mount.h"
  26 #include "xfs_inode.h"
  27 #include "xfs_bmap.h"
  28 #include "xfs_bmap_util.h"
  29 #include "xfs_bmap_btree.h"
  30 #include "xfs_alloc.h"
  31 #include "xfs_error.h"
  32 #include "xfs_trans.h"
  33 #include "xfs_trans_space.h"
  34 #include "xfs_trace.h"
  35 #include "xfs_buf.h"
  36 #include "xfs_icache.h"
  37 #include "xfs_rtalloc.h"
  38
  39
  40 /*
  41  * Read and return the summary information for a given extent size,
  42  * bitmap block combination.
  43  * Keeps track of a current summary block, so we don't keep reading
  44  * it from the buffer cache.
  45  */
  46 static int
  47 xfs_rtget_summary(
  48         xfs_mount_t     *mp,            /* file system mount structure */
  49         xfs_trans_t     *tp,            /* transaction pointer */
  50         int             log,            /* log2 of extent size */
  51         xfs_rtblock_t   bbno,           /* bitmap block number */
  52         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
  53         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
  54         xfs_suminfo_t   *sum)           /* out: summary info for this block */
  55 {
  56         return xfs_rtmodify_summary_int(mp, tp, log, bbno, 0, rbpp, rsb, sum);
  57 }
  58
  59 /*
  60  * Return whether there are any free extents in the size range given
  61  * by low and high, for the bitmap block bbno.
  62  */
  63 STATIC int                              /* error */
  64 xfs_rtany_summary(
  65         xfs_mount_t     *mp,            /* file system mount structure */
  66         xfs_trans_t     *tp,            /* transaction pointer */
  67         int             low,            /* low log2 extent size */
  68         int             high,           /* high log2 extent size */
  69         xfs_rtblock_t   bbno,           /* bitmap block number */
  70         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
  71         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
  72         int             *stat)          /* out: any good extents here? */
  73 {
  74         int             error;          /* error value */
  75         int             log;            /* loop counter, log2 of ext. size */
  76         xfs_suminfo_t   sum;            /* summary data */
  77
  78         /*
  79          * Loop over logs of extent sizes.  Order is irrelevant.
  80          */
  81         for (log = low; log <= high; log++) {
  82                 /*
  83                  * Get one summary datum.
  84                  */
  85                 error = xfs_rtget_summary(mp, tp, log, bbno, rbpp, rsb, &sum);
  86                 if (error) {
  87                         return error;
  88                 }
  89                 /*
  90                  * If there are any, return success.
  91                  */
  92                 if (sum) {
  93                         *stat = 1;
  94                         return 0;
  95                 }
  96         }
  97         /*
  98          * Found nothing, return failure.
  99          */
 100         *stat = 0;
 101         return 0;
 102 }
 103
 104
 105 /*
 106  * Copy and transform the summary file, given the old and new
 107  * parameters in the mount structures.
 108  */
 109 STATIC int                              /* error */
 110 xfs_rtcopy_summary(
 111         xfs_mount_t     *omp,           /* old file system mount point */
 112         xfs_mount_t     *nmp,           /* new file system mount point */
 113         xfs_trans_t     *tp)            /* transaction pointer */
 114 {
 115         xfs_rtblock_t   bbno;           /* bitmap block number */
 116         xfs_buf_t       *bp;            /* summary buffer */
 117         int             error;          /* error return value */
 118         int             log;            /* summary level number (log length) */
 119         xfs_suminfo_t   sum;            /* summary data */
 120         xfs_fsblock_t   sumbno;         /* summary block number */
 121
 122         bp = NULL;
 123         for (log = omp->m_rsumlevels - 1; log >= 0; log--) {
 124                 for (bbno = omp->m_sb.sb_rbmblocks - 1;
 125                      (xfs_srtblock_t)bbno >= 0;
 126                      bbno--) {
 127                         error = xfs_rtget_summary(omp, tp, log, bbno, &bp,
 128                                 &sumbno, &sum);
 129                         if (error)
 130                                 return error;
 131                         if (sum == 0)
 132                                 continue;
 133                         error = xfs_rtmodify_summary(omp, tp, log, bbno, -sum,
 134                                 &bp, &sumbno);
 135                         if (error)
 136                                 return error;
 137                         error = xfs_rtmodify_summary(nmp, tp, log, bbno, sum,
 138                                 &bp, &sumbno);
 139                         if (error)
 140                                 return error;
 141                         ASSERT(sum > 0);
 142                 }
 143         }
 144         return 0;
 145 }
 146 /*
 147  * Mark an extent specified by start and len allocated.
 148  * Updates all the summary information as well as the bitmap.
 149  */
 150 STATIC int                              /* error */
 151 xfs_rtallocate_range(
 152         xfs_mount_t     *mp,            /* file system mount point */
 153         xfs_trans_t     *tp,            /* transaction pointer */
 154         xfs_rtblock_t   start,          /* start block to allocate */
 155         xfs_extlen_t    len,            /* length to allocate */
 156         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
 157         xfs_fsblock_t   *rsb)           /* in/out: summary block number */
 158 {
 159         xfs_rtblock_t   end;            /* end of the allocated extent */
 160         int             error;          /* error value */
 161         xfs_rtblock_t   postblock = 0;  /* first block allocated > end */
 162         xfs_rtblock_t   preblock = 0;   /* first block allocated < start */
 163
 164         end = start + len - 1;
 165         /*
 166          * Assume we're allocating out of the middle of a free extent.
 167          * We need to find the beginning and end of the extent so we can
 168          * properly update the summary.
 169          */
 170         error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
 171         if (error) {
 172                 return error;
 173         }
 174         /*
 175          * Find the next allocated block (end of free extent).
 176          */
 177         error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
 178                 &postblock);
 179         if (error) {
 180                 return error;
 181         }
 182         /*
 183          * Decrement the summary information corresponding to the entire
 184          * (old) free extent.
 185          */
 186         error = xfs_rtmodify_summary(mp, tp,
 187                 XFS_RTBLOCKLOG(postblock + 1 - preblock),
 188                 XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
 189         if (error) {
 190                 return error;
 191         }
 192         /*
 193          * If there are blocks not being allocated at the front of the
 194          * old extent, add summary data for them to be free.
 195          */
 196         if (preblock < start) {
 197                 error = xfs_rtmodify_summary(mp, tp,
 198                         XFS_RTBLOCKLOG(start - preblock),
 199                         XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
 200                 if (error) {
 201                         return error;
 202                 }
 203         }
 204         /*
 205          * If there are blocks not being allocated at the end of the
 206          * old extent, add summary data for them to be free.
 207          */
 208         if (postblock > end) {
 209                 error = xfs_rtmodify_summary(mp, tp,
 210                         XFS_RTBLOCKLOG(postblock - end),
 211                         XFS_BITTOBLOCK(mp, end + 1), 1, rbpp, rsb);
 212                 if (error) {
 213                         return error;
 214                 }
 215         }
 216         /*
 217          * Modify the bitmap to mark this extent allocated.
 218          */
 219         error = xfs_rtmodify_range(mp, tp, start, len, 0);
 220         return error;
 221 }
 222
 223 /*
 224  * Attempt to allocate an extent minlen<=len<=maxlen starting from
 225  * bitmap block bbno.  If we don't get maxlen then use prod to trim
 226  * the length, if given.  Returns error; returns starting block in *rtblock.
 227  * The lengths are all in rtextents.
 228  */
 229 STATIC int                              /* error */
 230 xfs_rtallocate_extent_block(
 231         xfs_mount_t     *mp,            /* file system mount point */
 232         xfs_trans_t     *tp,            /* transaction pointer */
 233         xfs_rtblock_t   bbno,           /* bitmap block number */
 234         xfs_extlen_t    minlen,         /* minimum length to allocate */
 235         xfs_extlen_t    maxlen,         /* maximum length to allocate */
 236         xfs_extlen_t    *len,           /* out: actual length allocated */
 237         xfs_rtblock_t   *nextp,         /* out: next block to try */
 238         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
 239         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
 240         xfs_extlen_t    prod,           /* extent product factor */
 241         xfs_rtblock_t   *rtblock)       /* out: start block allocated */
 242 {
 243         xfs_rtblock_t   besti;          /* best rtblock found so far */
 244         xfs_rtblock_t   bestlen;        /* best length found so far */
 245         xfs_rtblock_t   end;            /* last rtblock in chunk */
 246         int             error;          /* error value */
 247         xfs_rtblock_t   i;              /* current rtblock trying */
 248         xfs_rtblock_t   next;           /* next rtblock to try */
 249         int             stat;           /* status from internal calls */
 250
 251         /*
 252          * Loop over all the extents starting in this bitmap block,
 253          * looking for one that's long enough.
 254          */
 255         for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
 256                 end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
 257              i <= end;
 258              i++) {
 259                 /*
 260                  * See if there's a free extent of maxlen starting at i.
 261                  * If it's not so then next will contain the first non-free.
 262                  */
 263                 error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
 264                 if (error) {
 265                         return error;
 266                 }
 267                 if (stat) {
 268                         /*
 269                          * i for maxlen is all free, allocate and return that.
 270                          */
 271                         error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
 272                                 rsb);
 273                         if (error) {
 274                                 return error;
 275                         }
 276                         *len = maxlen;
 277                         *rtblock = i;
 278                         return 0;
 279                 }
 280                 /*
 281                  * In the case where we have a variable-sized allocation
 282                  * request, figure out how big this free piece is,
 283                  * and if it's big enough for the minimum, and the best
 284                  * so far, remember it.
 285                  */
 286                 if (minlen < maxlen) {
 287                         xfs_rtblock_t   thislen;        /* this extent size */
 288
 289                         thislen = next - i;
 290                         if (thislen >= minlen && thislen > bestlen) {
 291                                 besti = i;
 292                                 bestlen = thislen;
 293                         }
 294                 }
 295                 /*
 296                  * If not done yet, find the start of the next free space.
 297                  */
 298                 if (next < end) {
 299                         error = xfs_rtfind_forw(mp, tp, next, end, &i);
 300                         if (error) {
 301                                 return error;
 302                         }
 303                 } else
 304                         break;
 305         }
 306         /*
 307          * Searched the whole thing & didn't find a maxlen free extent.
 308          */
 309         if (minlen < maxlen && besti != -1) {
 310                 xfs_extlen_t    p;      /* amount to trim length by */
 311
 312                 /*
 313                  * If size should be a multiple of prod, make that so.
 314                  */
 315                 if (prod > 1 && (p = do_mod(bestlen, prod)))
 316                         bestlen -= p;
 317                 /*
 318                  * Allocate besti for bestlen & return that.
 319                  */
 320                 error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
 321                 if (error) {
 322                         return error;
 323                 }
 324                 *len = bestlen;
 325                 *rtblock = besti;
 326                 return 0;
 327         }
 328         /*
 329          * Allocation failed.  Set *nextp to the next block to try.
 330          */
 331         *nextp = next;
 332         *rtblock = NULLRTBLOCK;
 333         return 0;
 334 }
 335
 336 /*
 337  * Allocate an extent of length minlen<=len<=maxlen, starting at block
 338  * bno.  If we don't get maxlen then use prod to trim the length, if given.
 339  * Returns error; returns starting block in *rtblock.
 340  * The lengths are all in rtextents.
 341  */
 342 STATIC int                              /* error */
 343 xfs_rtallocate_extent_exact(
 344         xfs_mount_t     *mp,            /* file system mount point */
 345         xfs_trans_t     *tp,            /* transaction pointer */
 346         xfs_rtblock_t   bno,            /* starting block number to allocate */
 347         xfs_extlen_t    minlen,         /* minimum length to allocate */
 348         xfs_extlen_t    maxlen,         /* maximum length to allocate */
 349         xfs_extlen_t    *len,           /* out: actual length allocated */
 350         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
 351         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
 352         xfs_extlen_t    prod,           /* extent product factor */
 353         xfs_rtblock_t   *rtblock)       /* out: start block allocated */
 354 {
 355         int             error;          /* error value */
 356         xfs_extlen_t    i;              /* extent length trimmed due to prod */
 357         int             isfree;         /* extent is free */
 358         xfs_rtblock_t   next;           /* next block to try (dummy) */
 359
 360         ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 361         /*
 362          * Check if the range in question (for maxlen) is free.
 363          */
 364         error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
 365         if (error) {
 366                 return error;
 367         }
 368         if (isfree) {
 369                 /*
 370                  * If it is, allocate it and return success.
 371                  */
 372                 error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
 373                 if (error) {
 374                         return error;
 375                 }
 376                 *len = maxlen;
 377                 *rtblock = bno;
 378                 return 0;
 379         }
 380         /*
 381          * If not, allocate what there is, if it's at least minlen.
 382          */
 383         maxlen = next - bno;
 384         if (maxlen < minlen) {
 385                 /*
 386                  * Failed, return failure status.
 387                  */
 388                 *rtblock = NULLRTBLOCK;
 389                 return 0;
 390         }
 391         /*
 392          * Trim off tail of extent, if prod is specified.
 393          */
 394         if (prod > 1 && (i = maxlen % prod)) {
 395                 maxlen -= i;
 396                 if (maxlen < minlen) {
 397                         /*
 398                          * Now we can't do it, return failure status.
 399                          */
 400                         *rtblock = NULLRTBLOCK;
 401                         return 0;
 402                 }
 403         }
 404         /*
 405          * Allocate what we can and return it.
 406          */
 407         error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
 408         if (error) {
 409                 return error;
 410         }
 411         *len = maxlen;
 412         *rtblock = bno;
 413         return 0;
 414 }
 415
 416 /*
 417  * Allocate an extent of length minlen<=len<=maxlen, starting as near
 418  * to bno as possible.  If we don't get maxlen then use prod to trim
 419  * the length, if given.  The lengths are all in rtextents.
 420  */
 421 STATIC int                              /* error */
 422 xfs_rtallocate_extent_near(
 423         xfs_mount_t     *mp,            /* file system mount point */
 424         xfs_trans_t     *tp,            /* transaction pointer */
 425         xfs_rtblock_t   bno,            /* starting block number to allocate */
 426         xfs_extlen_t    minlen,         /* minimum length to allocate */
 427         xfs_extlen_t    maxlen,         /* maximum length to allocate */
 428         xfs_extlen_t    *len,           /* out: actual length allocated */
 429         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
 430         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
 431         xfs_extlen_t    prod,           /* extent product factor */
 432         xfs_rtblock_t   *rtblock)       /* out: start block allocated */
 433 {
 434         int             any;            /* any useful extents from summary */
 435         xfs_rtblock_t   bbno;           /* bitmap block number */
 436         int             error;          /* error value */
 437         int             i;              /* bitmap block offset (loop control) */
 438         int             j;              /* secondary loop control */
 439         int             log2len;        /* log2 of minlen */
 440         xfs_rtblock_t   n;              /* next block to try */
 441         xfs_rtblock_t   r;              /* result block */
 442
 443         ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 444         /*
 445          * If the block number given is off the end, silently set it to
 446          * the last block.
 447          */
 448         if (bno >= mp->m_sb.sb_rextents)
 449                 bno = mp->m_sb.sb_rextents - 1;
 450         /*
 451          * Try the exact allocation first.
 452          */
 453         error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
 454                 rbpp, rsb, prod, &r);
 455         if (error) {
 456                 return error;
 457         }
 458         /*
 459          * If the exact allocation worked, return that.
 460          */
 461         if (r != NULLRTBLOCK) {
 462                 *rtblock = r;
 463                 return 0;
 464         }
 465         bbno = XFS_BITTOBLOCK(mp, bno);
 466         i = 0;
 467         ASSERT(minlen != 0);
 468         log2len = xfs_highbit32(minlen);
 469         /*
 470          * Loop over all bitmap blocks (bbno + i is current block).
 471          */
 472         for (;;) {
 473                 /*
 474                  * Get summary information of extents of all useful levels
 475                  * starting in this bitmap block.
 476                  */
 477                 error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
 478                         bbno + i, rbpp, rsb, &any);
 479                 if (error) {
 480                         return error;
 481                 }
 482                 /*
 483                  * If there are any useful extents starting here, try
 484                  * allocating one.
 485                  */
 486                 if (any) {
 487                         /*
 488                          * On the positive side of the starting location.
 489                          */
 490                         if (i >= 0) {
 491                                 /*
 492                                  * Try to allocate an extent starting in
 493                                  * this block.
 494                                  */
 495                                 error = xfs_rtallocate_extent_block(mp, tp,
 496                                         bbno + i, minlen, maxlen, len, &n, rbpp,
 497                                         rsb, prod, &r);
 498                                 if (error) {
 499                                         return error;
 500                                 }
 501                                 /*
 502                                  * If it worked, return it.
 503                                  */
 504                                 if (r != NULLRTBLOCK) {
 505                                         *rtblock = r;
 506                                         return 0;
 507                                 }
 508                         }
 509                         /*
 510                          * On the negative side of the starting location.
 511                          */
 512                         else {          /* i < 0 */
 513                                 /*
 514                                  * Loop backwards through the bitmap blocks from
 515                                  * the starting point-1 up to where we are now.
 516                                  * There should be an extent which ends in this
 517                                  * bitmap block and is long enough.
 518                                  */
 519                                 for (j = -1; j > i; j--) {
 520                                         /*
 521                                          * Grab the summary information for
 522                                          * this bitmap block.
 523                                          */
 524                                         error = xfs_rtany_summary(mp, tp,
 525                                                 log2len, mp->m_rsumlevels - 1,
 526                                                 bbno + j, rbpp, rsb, &any);
 527                                         if (error) {
 528                                                 return error;
 529                                         }
 530                                         /*
 531                                          * If there's no extent given in the
 532                                          * summary that means the extent we
 533                                          * found must carry over from an
 534                                          * earlier block.  If there is an
 535                                          * extent given, we've already tried
 536                                          * that allocation, don't do it again.
 537                                          */
 538                                         if (any)
 539                                                 continue;
 540                                         error = xfs_rtallocate_extent_block(mp,
 541                                                 tp, bbno + j, minlen, maxlen,
 542                                                 len, &n, rbpp, rsb, prod, &r);
 543                                         if (error) {
 544                                                 return error;
 545                                         }
 546                                         /*
 547                                          * If it works, return the extent.
 548                                          */
 549                                         if (r != NULLRTBLOCK) {
 550                                                 *rtblock = r;
 551                                                 return 0;
 552                                         }
 553                                 }
 554                                 /*
 555                                  * There weren't intervening bitmap blocks
 556                                  * with a long enough extent, or the
 557                                  * allocation didn't work for some reason
 558                                  * (i.e. it's a little * too short).
 559                                  * Try to allocate from the summary block
 560                                  * that we found.
 561                                  */
 562                                 error = xfs_rtallocate_extent_block(mp, tp,
 563                                         bbno + i, minlen, maxlen, len, &n, rbpp,
 564                                         rsb, prod, &r);
 565                                 if (error) {
 566                                         return error;
 567                                 }
 568                                 /*
 569                                  * If it works, return the extent.
 570                                  */
 571                                 if (r != NULLRTBLOCK) {
 572                                         *rtblock = r;
 573                                         return 0;
 574                                 }
 575                         }
 576                 }
 577                 /*
 578                  * Loop control.  If we were on the positive side, and there's
 579                  * still more blocks on the negative side, go there.
 580                  */
 581                 if (i > 0 && (int)bbno - i >= 0)
 582                         i = -i;
 583                 /*
 584                  * If positive, and no more negative, but there are more
 585                  * positive, go there.
 586                  */
 587                 else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
 588                         i++;
 589                 /*
 590                  * If negative or 0 (just started), and there are positive
 591                  * blocks to go, go there.  The 0 case moves to block 1.
 592                  */
 593                 else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
 594                         i = 1 - i;
 595                 /*
 596                  * If negative or 0 and there are more negative blocks,
 597                  * go there.
 598                  */
 599                 else if (i <= 0 && (int)bbno + i > 0)
 600                         i--;
 601                 /*
 602                  * Must be done.  Return failure.
 603                  */
 604                 else
 605                         break;
 606         }
 607         *rtblock = NULLRTBLOCK;
 608         return 0;
 609 }
 610
 611 /*
 612  * Allocate an extent of length minlen<=len<=maxlen, with no position
 613  * specified.  If we don't get maxlen then use prod to trim
 614  * the length, if given.  The lengths are all in rtextents.
 615  */
 616 STATIC int                              /* error */
 617 xfs_rtallocate_extent_size(
 618         xfs_mount_t     *mp,            /* file system mount point */
 619         xfs_trans_t     *tp,            /* transaction pointer */
 620         xfs_extlen_t    minlen,         /* minimum length to allocate */
 621         xfs_extlen_t    maxlen,         /* maximum length to allocate */
 622         xfs_extlen_t    *len,           /* out: actual length allocated */
 623         xfs_buf_t       **rbpp,         /* in/out: summary block buffer */
 624         xfs_fsblock_t   *rsb,           /* in/out: summary block number */
 625         xfs_extlen_t    prod,           /* extent product factor */
 626         xfs_rtblock_t   *rtblock)       /* out: start block allocated */
 627 {
 628         int             error;          /* error value */
 629         int             i;              /* bitmap block number */
 630         int             l;              /* level number (loop control) */
 631         xfs_rtblock_t   n;              /* next block to be tried */
 632         xfs_rtblock_t   r;              /* result block number */
 633         xfs_suminfo_t   sum;            /* summary information for extents */
 634
 635         ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 636         ASSERT(maxlen != 0);
 637
 638         /*
 639          * Loop over all the levels starting with maxlen.
 640          * At each level, look at all the bitmap blocks, to see if there
 641          * are extents starting there that are long enough (>= maxlen).
 642          * Note, only on the initial level can the allocation fail if
 643          * the summary says there's an extent.
 644          */
 645         for (l = xfs_highbit32(maxlen); l < mp->m_rsumlevels; l++) {
 646                 /*
 647                  * Loop over all the bitmap blocks.
 648                  */
 649                 for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
 650                         /*
 651                          * Get the summary for this level/block.
 652                          */
 653                         error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
 654                                 &sum);
 655                         if (error) {
 656                                 return error;
 657                         }
 658                         /*
 659                          * Nothing there, on to the next block.
 660                          */
 661                         if (!sum)
 662                                 continue;
 663                         /*
 664                          * Try allocating the extent.
 665                          */
 666                         error = xfs_rtallocate_extent_block(mp, tp, i, maxlen,
 667                                 maxlen, len, &n, rbpp, rsb, prod, &r);
 668                         if (error) {
 669                                 return error;
 670                         }
 671                         /*
 672                          * If it worked, return that.
 673                          */
 674                         if (r != NULLRTBLOCK) {
 675                                 *rtblock = r;
 676                                 return 0;
 677                         }
 678                         /*
 679                          * If the "next block to try" returned from the
 680                          * allocator is beyond the next bitmap block,
 681                          * skip to that bitmap block.
 682                          */
 683                         if (XFS_BITTOBLOCK(mp, n) > i + 1)
 684                                 i = XFS_BITTOBLOCK(mp, n) - 1;
 685                 }
 686         }
 687         /*
 688          * Didn't find any maxlen blocks.  Try smaller ones, unless
 689          * we're asking for a fixed size extent.
 690          */
 691         if (minlen > --maxlen) {
 692                 *rtblock = NULLRTBLOCK;
 693                 return 0;
 694         }
 695         ASSERT(minlen != 0);
 696         ASSERT(maxlen != 0);
 697
 698         /*
 699          * Loop over sizes, from maxlen down to minlen.
 700          * This time, when we do the allocations, allow smaller ones
 701          * to succeed.
 702          */
 703         for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
 704                 /*
 705                  * Loop over all the bitmap blocks, try an allocation
 706                  * starting in that block.
 707                  */
 708                 for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
 709                         /*
 710                          * Get the summary information for this level/block.
 711                          */
 712                         error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
 713                                                   &sum);
 714                         if (error) {
 715                                 return error;
 716                         }
 717                         /*
 718                          * If nothing there, go on to next.
 719                          */
 720                         if (!sum)
 721                                 continue;
 722                         /*
 723                          * Try the allocation.  Make sure the specified
 724                          * minlen/maxlen are in the possible range for
 725                          * this summary level.
 726                          */
 727                         error = xfs_rtallocate_extent_block(mp, tp, i,
 728                                         XFS_RTMAX(minlen, 1 << l),
 729                                         XFS_RTMIN(maxlen, (1 << (l + 1)) - 1),
 730                                         len, &n, rbpp, rsb, prod, &r);
 731                         if (error) {
 732                                 return error;
 733                         }
 734                         /*
 735                          * If it worked, return that extent.
 736                          */
 737                         if (r != NULLRTBLOCK) {
 738                                 *rtblock = r;
 739                                 return 0;
 740                         }
 741                         /*
 742                          * If the "next block to try" returned from the
 743                          * allocator is beyond the next bitmap block,
 744                          * skip to that bitmap block.
 745                          */
 746                         if (XFS_BITTOBLOCK(mp, n) > i + 1)
 747                                 i = XFS_BITTOBLOCK(mp, n) - 1;
 748                 }
 749         }
 750         /*
 751          * Got nothing, return failure.
 752          */
 753         *rtblock = NULLRTBLOCK;
 754         return 0;
 755 }
 756
 757 /*
 758  * Allocate space to the bitmap or summary file, and zero it, for growfs.
 759  */
 760 STATIC int
 761 xfs_growfs_rt_alloc(
 762         struct xfs_mount        *mp,            /* file system mount point */
 763         xfs_extlen_t            oblocks,        /* old count of blocks */
 764         xfs_extlen_t            nblocks,        /* new count of blocks */
 765         struct xfs_inode        *ip)            /* inode (bitmap/summary) */
 766 {
 767         xfs_fileoff_t           bno;            /* block number in file */
 768         struct xfs_buf          *bp;    /* temporary buffer for zeroing */
 769         xfs_daddr_t             d;              /* disk block address */
 770         int                     error;          /* error return value */
 771         xfs_fsblock_t           firstblock;/* first block allocated in xaction */
 772         struct xfs_bmap_free    flist;          /* list of freed blocks */
 773         xfs_fsblock_t           fsbno;          /* filesystem block for bno */
 774         struct xfs_bmbt_irec    map;            /* block map output */
 775         int                     nmap;           /* number of block maps */
 776         int                     resblks;        /* space reservation */
 777         struct xfs_trans        *tp;
 778
 779         /*
 780          * Allocate space to the file, as necessary.
 781          */
 782         while (oblocks < nblocks) {
 783                 tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ALLOC);
 784                 resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
 785                 /*
 786                  * Reserve space & log for one extent added to the file.
 787                  */
 788                 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_growrtalloc,
 789                                           resblks, 0);
 790                 if (error)
 791                         goto out_trans_cancel;
 792                 /*
 793                  * Lock the inode.
 794                  */
 795                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 796                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 797
 798                 xfs_bmap_init(&flist, &firstblock);
 799                 /*
 800                  * Allocate blocks to the bitmap file.
 801                  */
 802                 nmap = 1;
 803                 error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks,
 804                                         XFS_BMAPI_METADATA, &firstblock,
 805                                         resblks, &map, &nmap, &flist);
 806                 if (!error && nmap < 1)
 807                         error = -ENOSPC;
 808                 if (error)
 809                         goto out_bmap_cancel;
 810                 /*
 811                  * Free any blocks freed up in the transaction, then commit.
 812                  */
 813                 error = xfs_bmap_finish(&tp, &flist, NULL);
 814                 if (error)
 815                         goto out_bmap_cancel;
 816                 error = xfs_trans_commit(tp);
 817                 if (error)
 818                         return error;
 819                 /*
 820                  * Now we need to clear the allocated blocks.
 821                  * Do this one block per transaction, to keep it simple.
 822                  */
 823                 for (bno = map.br_startoff, fsbno = map.br_startblock;
 824                      bno < map.br_startoff + map.br_blockcount;
 825                      bno++, fsbno++) {
 826                         tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ZERO);
 827                         /*
 828                          * Reserve log for one block zeroing.
 829                          */
 830                         error = xfs_trans_reserve(tp, &M_RES(mp)->tr_growrtzero,
 831                                                   0, 0);
 832                         if (error)
 833                                 goto out_trans_cancel;
 834                         /*
 835                          * Lock the bitmap inode.
 836                          */
 837                         xfs_ilock(ip, XFS_ILOCK_EXCL);
 838                         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 839                         /*
 840                          * Get a buffer for the block.
 841                          */
 842                         d = XFS_FSB_TO_DADDR(mp, fsbno);
 843                         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
 844                                 mp->m_bsize, 0);
 845                         if (bp == NULL) {
 846                                 error = -EIO;
 847                                 goto out_trans_cancel;
 848                         }
 849                         memset(bp->b_addr, 0, mp->m_sb.sb_blocksize);
 850                         xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
 851                         /*
 852                          * Commit the transaction.
 853                          */
 854                         error = xfs_trans_commit(tp);
 855                         if (error)
 856                                 return error;
 857                 }
 858                 /*
 859                  * Go on to the next extent, if any.
 860                  */
 861                 oblocks = map.br_startoff + map.br_blockcount;
 862         }
 863
 864         return 0;
 865
 866 out_bmap_cancel:
 867         xfs_bmap_cancel(&flist);
 868 out_trans_cancel:
 869         xfs_trans_cancel(tp);
 870         return error;
 871 }
 872
 873 /*
 874  * Visible (exported) functions.
 875  */
 876
 877 /*
 878  * Grow the realtime area of the filesystem.
 879  */
 880 int
 881 xfs_growfs_rt(
 882         xfs_mount_t     *mp,            /* mount point for filesystem */
 883         xfs_growfs_rt_t *in)            /* growfs rt input struct */
 884 {
 885         xfs_rtblock_t   bmbno;          /* bitmap block number */
 886         xfs_buf_t       *bp;            /* temporary buffer */
 887         int             error;          /* error return value */
 888         xfs_mount_t     *nmp;           /* new (fake) mount structure */
 889         xfs_rfsblock_t  nrblocks;       /* new number of realtime blocks */
 890         xfs_extlen_t    nrbmblocks;     /* new number of rt bitmap blocks */
 891         xfs_rtblock_t   nrextents;      /* new number of realtime extents */
 892         uint8_t         nrextslog;      /* new log2 of sb_rextents */
 893         xfs_extlen_t    nrsumblocks;    /* new number of summary blocks */
 894         uint            nrsumlevels;    /* new rt summary levels */
 895         uint            nrsumsize;      /* new size of rt summary, bytes */
 896         xfs_sb_t        *nsbp;          /* new superblock */
 897         xfs_extlen_t    rbmblocks;      /* current number of rt bitmap blocks */
 898         xfs_extlen_t    rsumblocks;     /* current number of rt summary blks */
 899         xfs_sb_t        *sbp;           /* old superblock */
 900         xfs_fsblock_t   sumbno;         /* summary block number */
 901
 902         sbp = &mp->m_sb;
 903         /*
 904          * Initial error checking.
 905          */
 906         if (!capable(CAP_SYS_ADMIN))
 907                 return -EPERM;
 908         if (mp->m_rtdev_targp == NULL || mp->m_rbmip == NULL ||
 909             (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
 910             (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
 911                 return -EINVAL;
 912         if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
 913                 return error;
 914         /*
 915          * Read in the last block of the device, make sure it exists.
 916          */
 917         error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 918                                 XFS_FSB_TO_BB(mp, nrblocks - 1),
 919                                 XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
 920         if (error)
 921                 return error;
 922         xfs_buf_relse(bp);
 923
 924         /*
 925          * Calculate new parameters.  These are the final values to be reached.
 926          */
 927         nrextents = nrblocks;
 928         do_div(nrextents, in->extsize);
 929         nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
 930         nrextslog = xfs_highbit32(nrextents);
 931         nrsumlevels = nrextslog + 1;
 932         nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks;
 933         nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
 934         nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
 935         /*
 936          * New summary size can't be more than half the size of
 937          * the log.  This prevents us from getting a log overflow,
 938          * since we'll log basically the whole summary file at once.
 939          */
 940         if (nrsumblocks > (mp->m_sb.sb_logblocks >> 1))
 941                 return -EINVAL;
 942         /*
 943          * Get the old block counts for bitmap and summary inodes.
 944          * These can't change since other growfs callers are locked out.
 945          */
 946         rbmblocks = XFS_B_TO_FSB(mp, mp->m_rbmip->i_d.di_size);
 947         rsumblocks = XFS_B_TO_FSB(mp, mp->m_rsumip->i_d.di_size);
 948         /*
 949          * Allocate space to the bitmap and summary files, as necessary.
 950          */
 951         error = xfs_growfs_rt_alloc(mp, rbmblocks, nrbmblocks, mp->m_rbmip);
 952         if (error)
 953                 return error;
 954         error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks, mp->m_rsumip);
 955         if (error)
 956                 return error;
 957         /*
 958          * Allocate a new (fake) mount/sb.
 959          */
 960         nmp = kmem_alloc(sizeof(*nmp), KM_SLEEP);
 961         /*
 962          * Loop over the bitmap blocks.
 963          * We will do everything one bitmap block at a time.
 964          * Skip the current block if it is exactly full.
 965          * This also deals with the case where there were no rtextents before.
 966          */
 967         for (bmbno = sbp->sb_rbmblocks -
 968                      ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
 969              bmbno < nrbmblocks;
 970              bmbno++) {
 971                 xfs_trans_t     *tp;
 972
 973                 *nmp = *mp;
 974                 nsbp = &nmp->m_sb;
 975                 /*
 976                  * Calculate new sb and mount fields for this round.
 977                  */
 978                 nsbp->sb_rextsize = in->extsize;
 979                 nsbp->sb_rbmblocks = bmbno + 1;
 980                 nsbp->sb_rblocks =
 981                         XFS_RTMIN(nrblocks,
 982                                   nsbp->sb_rbmblocks * NBBY *
 983                                   nsbp->sb_blocksize * nsbp->sb_rextsize);
 984                 nsbp->sb_rextents = nsbp->sb_rblocks;
 985                 do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
 986                 ASSERT(nsbp->sb_rextents != 0);
 987                 nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
 988                 nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
 989                 nrsumsize =
 990                         (uint)sizeof(xfs_suminfo_t) * nrsumlevels *
 991                         nsbp->sb_rbmblocks;
 992                 nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
 993                 nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
 994                 /*
 995                  * Start a transaction, get the log reservation.
 996                  */
 997                 tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_FREE);
 998                 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_growrtfree,
 999                                           0, 0);
1000                 if (error)
1001                         goto error_cancel;
1002                 /*
1003                  * Lock out other callers by grabbing the bitmap inode lock.
1004                  */
1005                 xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
1006                 xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
1007                 /*
1008                  * Update the bitmap inode's size.
1009                  */
1010                 mp->m_rbmip->i_d.di_size =
1011                         nsbp->sb_rbmblocks * nsbp->sb_blocksize;
1012                 xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
1013                 /*
1014                  * Get the summary inode into the transaction.
1015                  */
1016                 xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL);
1017                 xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
1018                 /*
1019                  * Update the summary inode's size.
1020                  */
1021                 mp->m_rsumip->i_d.di_size = nmp->m_rsumsize;
1022                 xfs_trans_log_inode(tp, mp->m_rsumip, XFS_ILOG_CORE);
1023                 /*
1024                  * Copy summary data from old to new sizes.
1025                  * Do this when the real size (not block-aligned) changes.
1026                  */
1027                 if (sbp->sb_rbmblocks != nsbp->sb_rbmblocks ||
1028                     mp->m_rsumlevels != nmp->m_rsumlevels) {
1029                         error = xfs_rtcopy_summary(mp, nmp, tp);
1030                         if (error)
1031                                 goto error_cancel;
1032                 }
1033                 /*
1034                  * Update superblock fields.
1035                  */
1036                 if (nsbp->sb_rextsize != sbp->sb_rextsize)
1037                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
1038                                 nsbp->sb_rextsize - sbp->sb_rextsize);
1039                 if (nsbp->sb_rbmblocks != sbp->sb_rbmblocks)
1040                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
1041                                 nsbp->sb_rbmblocks - sbp->sb_rbmblocks);
1042                 if (nsbp->sb_rblocks != sbp->sb_rblocks)
1043                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
1044                                 nsbp->sb_rblocks - sbp->sb_rblocks);
1045                 if (nsbp->sb_rextents != sbp->sb_rextents)
1046                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
1047                                 nsbp->sb_rextents - sbp->sb_rextents);
1048                 if (nsbp->sb_rextslog != sbp->sb_rextslog)
1049                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
1050                                 nsbp->sb_rextslog - sbp->sb_rextslog);
1051                 /*
1052                  * Free new extent.
1053                  */
1054                 bp = NULL;
1055                 error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
1056                         nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
1057                 if (error) {
1058 error_cancel:
1059                         xfs_trans_cancel(tp);
1060                         break;
1061                 }
1062                 /*
1063                  * Mark more blocks free in the superblock.
1064                  */
1065                 xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS,
1066                         nsbp->sb_rextents - sbp->sb_rextents);
1067                 /*
1068                  * Update mp values into the real mp structure.
1069                  */
1070                 mp->m_rsumlevels = nrsumlevels;
1071                 mp->m_rsumsize = nrsumsize;
1072
1073                 error = xfs_trans_commit(tp);
1074                 if (error)
1075                         break;
1076         }
1077
1078         /*
1079          * Free the fake mp structure.
1080          */
1081         kmem_free(nmp);
1082
1083         return error;
1084 }
1085
1086 /*
1087  * Allocate an extent in the realtime subvolume, with the usual allocation
1088  * parameters.  The length units are all in realtime extents, as is the
1089  * result block number.
1090  */
1091 int                                     /* error */
1092 xfs_rtallocate_extent(
1093         xfs_trans_t     *tp,            /* transaction pointer */
1094         xfs_rtblock_t   bno,            /* starting block number to allocate */
1095         xfs_extlen_t    minlen,         /* minimum length to allocate */
1096         xfs_extlen_t    maxlen,         /* maximum length to allocate */
1097         xfs_extlen_t    *len,           /* out: actual length allocated */
1098         xfs_alloctype_t type,           /* allocation type XFS_ALLOCTYPE... */
1099         int             wasdel,         /* was a delayed allocation extent */
1100         xfs_extlen_t    prod,           /* extent product factor */
1101         xfs_rtblock_t   *rtblock)       /* out: start block allocated */
1102 {
1103         xfs_mount_t     *mp = tp->t_mountp;
1104         int             error;          /* error value */
1105         xfs_rtblock_t   r;              /* result allocated block */
1106         xfs_fsblock_t   sb;             /* summary file block number */
1107         xfs_buf_t       *sumbp;         /* summary file block buffer */
1108
1109         ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
1110         ASSERT(minlen > 0 && minlen <= maxlen);
1111
1112         /*
1113          * If prod is set then figure out what to do to minlen and maxlen.
1114          */
1115         if (prod > 1) {
1116                 xfs_extlen_t    i;
1117
1118                 if ((i = maxlen % prod))
1119                         maxlen -= i;
1120                 if ((i = minlen % prod))
1121                         minlen += prod - i;
1122                 if (maxlen < minlen) {
1123                         *rtblock = NULLRTBLOCK;
1124                         return 0;
1125                 }
1126         }
1127
1128         sumbp = NULL;
1129         /*
1130          * Allocate by size, or near another block, or exactly at some block.
1131          */
1132         switch (type) {
1133         case XFS_ALLOCTYPE_ANY_AG:
1134                 error = xfs_rtallocate_extent_size(mp, tp, minlen, maxlen, len,
1135                                 &sumbp, &sb, prod, &r);
1136                 break;
1137         case XFS_ALLOCTYPE_NEAR_BNO:
1138                 error = xfs_rtallocate_extent_near(mp, tp, bno, minlen, maxlen,
1139                                 len, &sumbp, &sb, prod, &r);
1140                 break;
1141         case XFS_ALLOCTYPE_THIS_BNO:
1142                 error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen,
1143                                 len, &sumbp, &sb, prod, &r);
1144                 break;
1145         default:
1146                 error = -EIO;
1147                 ASSERT(0);
1148         }
1149         if (error)
1150                 return error;
1151
1152         /*
1153          * If it worked, update the superblock.
1154          */
1155         if (r != NULLRTBLOCK) {
1156                 long    slen = (long)*len;
1157
1158                 ASSERT(*len >= minlen && *len <= maxlen);
1159                 if (wasdel)
1160                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FREXTENTS, -slen);
1161                 else
1162                         xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, -slen);
1163         }
1164         *rtblock = r;
1165         return 0;
1166 }
1167
1168 /*
1169  * Initialize realtime fields in the mount structure.
1170  */
1171 int                             /* error */
1172 xfs_rtmount_init(
1173         struct xfs_mount        *mp)    /* file system mount structure */
1174 {
1175         struct xfs_buf          *bp;    /* buffer for last block of subvolume */
1176         struct xfs_sb           *sbp;   /* filesystem superblock copy in mount */
1177         xfs_daddr_t             d;      /* address of last block of subvolume */
1178         int                     error;
1179
1180         sbp = &mp->m_sb;
1181         if (sbp->sb_rblocks == 0)
1182                 return 0;
1183         if (mp->m_rtdev_targp == NULL) {
1184                 xfs_warn(mp,
1185         "Filesystem has a realtime volume, use rtdev=device option");
1186                 return -ENODEV;
1187         }
1188         mp->m_rsumlevels = sbp->sb_rextslog + 1;
1189         mp->m_rsumsize =
1190                 (uint)sizeof(xfs_suminfo_t) * mp->m_rsumlevels *
1191                 sbp->sb_rbmblocks;
1192         mp->m_rsumsize = roundup(mp->m_rsumsize, sbp->sb_blocksize);
1193         mp->m_rbmip = mp->m_rsumip = NULL;
1194         /*
1195          * Check that the realtime section is an ok size.
1196          */
1197         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
1198         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
1199                 xfs_warn(mp, "realtime mount -- %llu != %llu",
1200                         (unsigned long long) XFS_BB_TO_FSB(mp, d),
1201                         (unsigned long long) mp->m_sb.sb_rblocks);
1202                 return -EFBIG;
1203         }
1204         error = xfs_buf_read_uncached(mp->m_rtdev_targp,
1205                                         d - XFS_FSB_TO_BB(mp, 1),
1206                                         XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
1207         if (error) {
1208                 xfs_warn(mp, "realtime device size check failed");
1209                 return error;
1210         }
1211         xfs_buf_relse(bp);
1212         return 0;
1213 }
1214
1215 /*
1216  * Get the bitmap and summary inodes into the mount structure
1217  * at mount time.
1218  */
1219 int                                     /* error */
1220 xfs_rtmount_inodes(
1221         xfs_mount_t     *mp)            /* file system mount structure */
1222 {
1223         int             error;          /* error return value */
1224         xfs_sb_t        *sbp;
1225
1226         sbp = &mp->m_sb;
1227         if (sbp->sb_rbmino == NULLFSINO)
1228                 return 0;
1229         error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip);
1230         if (error)
1231                 return error;
1232         ASSERT(mp->m_rbmip != NULL);
1233         ASSERT(sbp->sb_rsumino != NULLFSINO);
1234         error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip);
1235         if (error) {
1236                 IRELE(mp->m_rbmip);
1237                 return error;
1238         }
1239         ASSERT(mp->m_rsumip != NULL);
1240         return 0;
1241 }
1242
1243 void
1244 xfs_rtunmount_inodes(
1245         struct xfs_mount        *mp)
1246 {
1247         if (mp->m_rbmip)
1248                 IRELE(mp->m_rbmip);
1249         if (mp->m_rsumip)
1250                 IRELE(mp->m_rsumip);
1251 }
1252
1253 /*
1254  * Pick an extent for allocation at the start of a new realtime file.
1255  * Use the sequence number stored in the atime field of the bitmap inode.
1256  * Translate this to a fraction of the rtextents, and return the product
1257  * of rtextents and the fraction.
1258  * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
1259  */
1260 int                                     /* error */
1261 xfs_rtpick_extent(
1262         xfs_mount_t     *mp,            /* file system mount point */
1263         xfs_trans_t     *tp,            /* transaction pointer */
1264         xfs_extlen_t    len,            /* allocation length (rtextents) */
1265         xfs_rtblock_t   *pick)          /* result rt extent */
1266 {
1267         xfs_rtblock_t   b;              /* result block */
1268         int             log2;           /* log of sequence number */
1269         __uint64_t      resid;          /* residual after log removed */
1270         __uint64_t      seq;            /* sequence number of file creation */
1271         __uint64_t      *seqp;          /* pointer to seqno in inode */
1272
1273         ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
1274
1275         seqp = (__uint64_t *)&VFS_I(mp->m_rbmip)->i_atime;
1276         if (!(mp->m_rbmip->i_d.di_flags & XFS_DIFLAG_NEWRTBM)) {
1277                 mp->m_rbmip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
1278                 *seqp = 0;
1279         }
1280         seq = *seqp;
1281         if ((log2 = xfs_highbit64(seq)) == -1)
1282                 b = 0;
1283         else {
1284                 resid = seq - (1ULL << log2);
1285                 b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
1286                     (log2 + 1);
1287                 if (b >= mp->m_sb.sb_rextents)
1288                         b = do_mod(b, mp->m_sb.sb_rextents);
1289                 if (b + len > mp->m_sb.sb_rextents)
1290                         b = mp->m_sb.sb_rextents - len;
1291         }
1292         *seqp = seq + 1;
1293         xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
1294         *pick = b;
1295         return 0;
1296 }