sys/vfs/hammer2/hammer2_chain.c

   1 /*
   2  * Copyright (c) 2011-2012 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@dragonflybsd.org>
   6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35 /*
  36  * This subsystem handles direct and indirect block searches, recursions,
  37  * creation, and deletion.  Chains of blockrefs are tracked and modifications
  38  * are flag for propagation... eventually all the way back to the volume
  39  * header.
  40  */
  41
  42 #include <sys/cdefs.h>
  43 #include <sys/cdefs.h>
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/types.h>
  47 #include <sys/lock.h>
  48 #include <sys/uuid.h>
  49
  50 #include "hammer2.h"
  51
  52 SPLAY_GENERATE(hammer2_chain_splay, hammer2_chain, snode, hammer2_chain_cmp);
  53
  54 static int hammer2_indirect_optimize;   /* XXX SYSCTL */
  55
  56 static hammer2_chain_t *hammer2_chain_create_indirect(
  57                         hammer2_mount_t *hmp, hammer2_chain_t *parent,
  58                         hammer2_key_t key, int keybits);
  59
  60 /*
  61  * Compare function for chain splay tree
  62  */
  63 int
  64 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
  65 {
  66         return(chain2->index - chain1->index);
  67 }
  68
  69 /*
  70  * Allocate a new disconnected chain element representing the specified
  71  * bref.  The chain element is locked exclusively and refs is set to 1.
  72  *
  73  * This essentially allocates a system memory structure representing one
  74  * of the media structure types, including inodes.
  75  */
  76 hammer2_chain_t *
  77 hammer2_chain_alloc(hammer2_mount_t *hmp, hammer2_blockref_t *bref)
  78 {
  79         hammer2_chain_t *chain;
  80         hammer2_inode_t *ip;
  81         hammer2_indblock_t *np;
  82         hammer2_data_t *dp;
  83
  84         /*
  85          * Construct the appropriate system structure.
  86          */
  87         switch(bref->type) {
  88         case HAMMER2_BREF_TYPE_INODE:
  89                 ip = kmalloc(sizeof(*ip), hmp->minode, M_WAITOK | M_ZERO);
  90                 chain = &ip->chain;
  91                 chain->u.ip = ip;
  92                 lockinit(&chain->lk, "inode", 0, LK_CANRECURSE);
  93                 ip->hmp = hmp;
  94                 break;
  95         case HAMMER2_BREF_TYPE_INDIRECT:
  96                 np = kmalloc(sizeof(*np), hmp->mchain, M_WAITOK | M_ZERO);
  97                 chain = &np->chain;
  98                 chain->u.np = np;
  99                 lockinit(&chain->lk, "iblk", 0, LK_CANRECURSE);
 100                 break;
 101         case HAMMER2_BREF_TYPE_DATA:
 102                 dp = kmalloc(sizeof(*dp), hmp->mchain, M_WAITOK | M_ZERO);
 103                 chain = &dp->chain;
 104                 chain->u.dp = dp;
 105                 lockinit(&chain->lk, "dblk", 0, LK_CANRECURSE);
 106                 break;
 107         case HAMMER2_BREF_TYPE_VOLUME:
 108                 chain = NULL;
 109                 panic("hammer2_chain_get: volume type illegal for op");
 110         default:
 111                 chain = NULL;
 112                 panic("hammer2_chain_get: unrecognized blockref type: %d",
 113                       bref->type);
 114         }
 115         chain->bref = *bref;
 116         chain->index = -1;      /* not yet assigned */
 117         chain->refs = 1;
 118         lockmgr(&chain->lk, LK_EXCLUSIVE);
 119
 120         return (chain);
 121 }
 122
 123 /*
 124  * Free a disconnected chain element
 125  */
 126 void
 127 hammer2_chain_free(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 128 {
 129         void *mem;
 130
 131         KKASSERT(chain->bp == NULL);
 132         KKASSERT(chain->data == NULL);
 133         KKASSERT(chain->bref.type != HAMMER2_BREF_TYPE_INODE ||
 134                  chain->u.ip->vp == NULL);
 135
 136         if ((mem = chain->u.mem) != NULL) {
 137                 chain->u.mem = NULL;
 138                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
 139                         kfree(mem, hmp->minode);
 140                 else
 141                         kfree(mem, hmp->mchain);
 142         }
 143 }
 144
 145 /*
 146  * Add a reference to a chain element (for shared access).  The chain
 147  * element must already have at least 1 ref controlled by the caller.
 148  */
 149 void
 150 hammer2_chain_ref(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 151 {
 152         KKASSERT(chain->refs > 0);
 153         atomic_add_int(&chain->refs, 1);
 154 }
 155
 156 /*
 157  * Drop the callers reference to the chain element.  If the ref count
 158  * reaches zero the chain element and its related structure (typically an
 159  * inode or indirect block) will be freed and the parent will be
 160  * recursively dropped.
 161  *
 162  * Modified elements hold an additional reference so it should not be
 163  * possible for the count on a modified element to drop to 0.
 164  *
 165  * The chain element must NOT be locked by the caller.
 166  *
 167  * The parent might or might not be locked by the caller but if so it
 168  * will also be referenced so we shouldn't recurse upward.
 169  */
 170 void
 171 hammer2_chain_drop(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 172 {
 173         hammer2_chain_t *parent;
 174         u_int refs;
 175
 176         while (chain) {
 177                 refs = chain->refs;
 178                 cpu_ccfence();
 179                 KKASSERT(refs > 0);
 180                 if (refs == 1) {
 181                         KKASSERT(chain != &hmp->vchain);
 182                         parent = chain->parent;
 183                         if (parent)
 184                                 lockmgr(&parent->lk, LK_EXCLUSIVE);
 185                         if (atomic_cmpset_int(&chain->refs, 1, 0)) {
 186                                 /*
 187                                  * Succeeded, recurse and drop parent
 188                                  */
 189                                 if (!(chain->flags & HAMMER2_CHAIN_DELETED)) {
 190                                         SPLAY_REMOVE(hammer2_chain_splay,
 191                                                      &parent->shead, chain);
 192                                         atomic_set_int(&chain->flags,
 193                                                        HAMMER2_CHAIN_DELETED);
 194                                         /* parent refs dropped via recursion */
 195                                 }
 196                                 chain->parent = NULL;
 197                                 if (parent)
 198                                         lockmgr(&parent->lk, LK_RELEASE);
 199                                 hammer2_chain_free(hmp, chain);
 200                                 chain = parent;
 201                                 /* recurse on parent */
 202                         } else {
 203                                 if (parent)
 204                                         lockmgr(&parent->lk, LK_RELEASE);
 205                                 /* retry the same chain */
 206                         }
 207                 } else {
 208                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1)) {
 209                                 /*
 210                                  * Succeeded, count did not reach zero so
 211                                  * cut out of the loop.
 212                                  */
 213                                 break;
 214                         }
 215                         /* retry the same chain */
 216                 }
 217         }
 218 }
 219
 220 /*
 221  * Lock a chain element, acquiring its data with I/O if necessary.
 222  *
 223  * Returns 0 on success or an error code if the data could not be acquired.
 224  * The chain element is locked either way.
 225  *
 226  * chain->data will be pointed either at the embedded data (e.g. for
 227  * inodes), in which case the buffer cache buffer is released, or will
 228  * point into the bp->b_data buffer with the bp left intact while locked.
 229  */
 230 int
 231 hammer2_chain_lock(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 232 {
 233         hammer2_blockref_t *bref;
 234         hammer2_off_t off_hi;
 235         size_t off_lo;
 236         int error;
 237         void *data;
 238
 239         /*
 240          * Lock the element.  Under certain conditions this might end up
 241          * being a recursive lock.
 242          */
 243         KKASSERT(chain->refs > 0);
 244         lockmgr(&chain->lk, LK_EXCLUSIVE);
 245
 246         /*
 247          * The volume header is a special case
 248          */
 249         if (chain->bref.type == HAMMER2_BREF_TYPE_VOLUME)
 250                 return(0);
 251
 252         /*
 253          * bp must be NULL, so if the data pointer is valid here it points
 254          * to embedded data and no I/O is necessary (whether modified or not).
 255          */
 256         KKASSERT(chain->bp == NULL);
 257         if (chain->data)
 258                 return (0);
 259
 260         /*
 261          * If data is NULL we must issue I/O.  Any error returns the error
 262          * code but leaves the chain locked.
 263          *
 264          * If the chain was modified a new bref will have already been
 265          * allocated and its related bp is probably still sitting in the
 266          * buffer cache.
 267          */
 268         bref = &chain->bref;
 269
 270         off_hi = bref->data_off & HAMMER2_OFF_MASK_HI;
 271         off_lo = (size_t)bref->data_off & HAMMER2_OFF_MASK_LO;
 272         KKASSERT(off_hi != 0);
 273         error = bread(hmp->devvp, off_hi, HAMMER2_PBUFSIZE, &chain->bp);
 274
 275         if (error) {
 276                 kprintf("hammer2_chain_get: I/O error %016jx: %d\n",
 277                         (intmax_t)off_hi, error);
 278                 brelse(chain->bp);
 279                 chain->bp = NULL;
 280                 return (error);
 281         }
 282
 283         /*
 284          * Setup the data pointer, either pointing it to an embedded data
 285          * structure and copying the data from the buffer, or pointint it
 286          * into the buffer.
 287          *
 288          * The buffer is not retained when copying to an embedded data
 289          * structure in order to avoid potential deadlocks or recursions
 290          * on the same physical buffer.
 291          */
 292         switch (bref->type) {
 293         case HAMMER2_BREF_TYPE_VOLUME:
 294                 /*
 295                  * Copy data from bp to embedded buffer
 296                  */
 297                 KKASSERT(0);    /* not yet - have mount use this soon */
 298                 KKASSERT(off_hi == 0);
 299                 bcopy((char *)chain->bp->b_data + off_lo,
 300                       &hmp->voldata, HAMMER2_PBUFSIZE);
 301                 chain->data = (void *)&hmp->voldata;
 302                 brelse(chain->bp);
 303                 chain->bp = NULL;
 304                 break;
 305         case HAMMER2_BREF_TYPE_INODE:
 306                 /*
 307                  * Copy data from bp to embedded buffer.
 308                  */
 309                 bcopy((char *)chain->bp->b_data + off_lo,
 310                       &chain->u.ip->ip_data,
 311                       HAMMER2_INODE_BYTES);
 312                 chain->data = (void *)&chain->u.ip->ip_data;
 313                 brelse(chain->bp);
 314                 chain->bp = NULL;
 315                 break;
 316         default:
 317                 /*
 318                  * Leave bp intact
 319                  */
 320                 data = (char *)chain->bp->b_data + off_lo;
 321                 chain->data = data;
 322                 break;
 323         }
 324         return (0);
 325 }
 326
 327 /*
 328  * Convert a locked chain that was retrieved read-only to read-write.
 329  *
 330  * If not already marked modified a new physical block will be allocated
 331  * and assigned to the bref.  If the data is pointing into an existing
 332  * bp it will be copied to the new bp and the new bp will replace the
 333  * existing bp.
 334  *
 335  * If the data is embedded we allocate the new physical block but don't
 336  * bother copying the data into it (yet).
 337  */
 338 void
 339 hammer2_chain_modify(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 340 {
 341         hammer2_chain_t *parent;
 342         struct buf *nbp;
 343         size_t bytes;
 344         void *ndata;
 345         int error;
 346
 347         /*
 348          * If the chain is already marked MODIFIED1 we can just return.
 349          */
 350         if (chain->flags & HAMMER2_CHAIN_MODIFIED1) {
 351                 KKASSERT(chain->data != NULL);
 352                 return;
 353         }
 354
 355         /*
 356          * A deleted inode may still be active but unreachable via sync
 357          * because it has been disconnected from the tree.  Do not allow
 358          * deleted inodes to be marked as being modified because this will
 359          * bump the refs and never get resolved by the sync, leaving the
 360          * inode structure allocated after umount.
 361          */
 362         if ((chain->flags & HAMMER2_CHAIN_DELETED) &&
 363             chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
 364                 KKASSERT(chain->data != NULL);
 365                 return;
 366         }
 367
 368         /*
 369          * Set MODIFIED1 and add a chain ref to prevent destruction.  Both
 370          * modified flags share the same ref.
 371          */
 372         atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
 373         if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
 374                 hammer2_chain_ref(hmp, chain);
 375
 376         /*
 377          * We must allocate the copy-on-write block.
 378          *
 379          * If the data is embedded no other action is required.
 380          *
 381          * If the data is not embedded we acquire and clear the
 382          * new block.  If chain->data is not NULL we then do the
 383          * copy-on-write.  chain->data will then be repointed to the new
 384          * buffer and the old buffer will be released.
 385          *
 386          * For newly created elements with no prior allocation we go
 387          * through the copy-on-write steps except without the copying part.
 388          */
 389
 390         bytes = 1 << (int)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
 391         if (chain != &hmp->vchain) {
 392                 chain->bref.data_off = hammer2_freemap_alloc(hmp, bytes);
 393                 /* XXX failed allocation */
 394         }
 395
 396         switch(chain->bref.type) {
 397         case HAMMER2_BREF_TYPE_VOLUME:          /* embedded */
 398         case HAMMER2_BREF_TYPE_INODE:           /* embedded */
 399                 /*
 400                  * data points to embedded structure, no copy needed
 401                  */
 402                 error = 0;
 403                 break;
 404         case HAMMER2_BREF_TYPE_INDIRECT:
 405         case HAMMER2_BREF_TYPE_DATA:
 406                 /*
 407                  * data (if not NULL) points into original bp, copy-on-write
 408                  * to new block.
 409                  */
 410                 KKASSERT(chain != &hmp->vchain);        /* safety */
 411                 if (bytes == HAMMER2_PBUFSIZE) {
 412                         nbp = getblk(hmp->devvp,
 413                                      chain->bref.data_off & HAMMER2_OFF_MASK_HI,
 414                                      HAMMER2_PBUFSIZE, 0, 0);
 415                         vfs_bio_clrbuf(nbp);
 416                         error = 0;
 417                 } else {
 418                         error = bread(hmp->devvp,
 419                                      chain->bref.data_off & HAMMER2_OFF_MASK_HI,
 420                                      HAMMER2_PBUFSIZE, &nbp);
 421                         KKASSERT(error == 0);/* XXX handle error */
 422                 }
 423                 ndata = nbp->b_data + (chain->bref.data_off &
 424                                        HAMMER2_OFF_MASK_LO);
 425                 if (chain->data) {
 426                         bcopy(chain->data, ndata, bytes);
 427                         KKASSERT(chain->bp != NULL);
 428                         brelse(chain->bp);
 429                 }
 430                 chain->bp = nbp;
 431                 chain->data = ndata;
 432                 break;
 433         default:
 434                 panic("hammer2_chain_modify: unknown bref type");
 435                 break;
 436
 437         }
 438
 439         /*
 440          * Recursively mark the parent chain elements so flushes can find
 441          * modified elements.
 442          *
 443          * NOTE: The flush code will modify a SUBMODIFIED-flagged chain
 444          *       during the flush recursion after clearing the parent's
 445          *       SUBMODIFIED bit.  We don't want to re-set the parent's
 446          *       SUBMODIFIED bit in this case!
 447          */
 448         if ((chain->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 449                 parent = chain->parent;
 450                 while (parent &&
 451                        (parent->flags & HAMMER2_CHAIN_SUBMODIFIED) == 0) {
 452                         atomic_set_int(&parent->flags,
 453                                        HAMMER2_CHAIN_SUBMODIFIED);
 454                         parent = parent->parent;
 455                 }
 456         }
 457 }
 458
 459 /*
 460  * Unlock a chain element without dropping its reference count.
 461  * (see hammer2_chain_put() to do both).
 462  *
 463  * Non-embedded data references (chain->bp != NULL) are returned to the
 464  * system and the data field is cleared in that case.  If modified the
 465  * dirty buffer is still returned to the system, can be flushed to disk by
 466  * the system at any time, and will be reconstituted/re-read as needed.
 467  */
 468 void
 469 hammer2_chain_unlock(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 470 {
 471         if (chain->bp) {
 472                 chain->data = NULL;
 473                 if (chain->flags & HAMMER2_CHAIN_MODIFIED1) {
 474                         if (chain->flags & HAMMER2_CHAIN_IOFLUSH) {
 475                                 atomic_clear_int(&chain->flags,
 476                                                  HAMMER2_CHAIN_IOFLUSH);
 477                                 bdwrite(chain->bp);
 478                         } else {
 479                                 bdwrite(chain->bp);
 480                         }
 481                 } else {
 482                         /* bp might still be dirty */
 483                         bqrelse(chain->bp);
 484                 }
 485                 chain->bp = NULL;
 486         }
 487         lockmgr(&chain->lk, LK_RELEASE);
 488 }
 489
 490 /*
 491  * Locate an in-memory chain.  The parent must be locked.  The in-memory
 492  * chain is returned or NULL if no in-memory chain is present.
 493  *
 494  * NOTE: A chain on-media might exist for this index when NULL is returned.
 495  */
 496 hammer2_chain_t *
 497 hammer2_chain_find(hammer2_mount_t *hmp, hammer2_chain_t *parent, int index)
 498 {
 499         hammer2_chain_t dummy;
 500         hammer2_chain_t *chain;
 501
 502         dummy.index = index;
 503         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead, &dummy);
 504         return (chain);
 505 }
 506
 507 /*
 508  * Return a locked chain structure with all associated data acquired.
 509  *
 510  * Caller must lock the parent on call, the returned child will be locked.
 511  */
 512 hammer2_chain_t *
 513 hammer2_chain_get(hammer2_mount_t *hmp, hammer2_chain_t *parent,
 514                   int index, int flags)
 515 {
 516         hammer2_blockref_t *bref;
 517         hammer2_chain_t *chain;
 518         hammer2_chain_t dummy;
 519
 520         /*
 521          * First see if we have a (possibly modified) chain element cached
 522          * for this (parent, index).  Acquire the data if necessary.
 523          *
 524          * If chain->data is non-NULL the chain should already be marked
 525          * modified.
 526          */
 527         dummy.index = index;
 528         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead, &dummy);
 529         if (chain) {
 530                 hammer2_chain_ref(hmp, chain);
 531                 if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 532                         hammer2_chain_lock(hmp, chain);
 533                 return(chain);
 534         }
 535
 536         /*
 537          * Otherwise lookup the bref and issue I/O (switch on the parent)
 538          */
 539         switch(parent->bref.type) {
 540         case HAMMER2_BREF_TYPE_INODE:
 541                 KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
 542                 bref = &parent->data->ipdata.u.blockset.blockref[index];
 543                 break;
 544         case HAMMER2_BREF_TYPE_INDIRECT:
 545                 KKASSERT(index >= 0 && index < HAMMER2_IND_COUNT);
 546                 bref = &parent->data->npdata.blockref[index];
 547                 break;
 548         case HAMMER2_BREF_TYPE_VOLUME:
 549                 KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
 550                 bref = &hmp->voldata.sroot_blockset.blockref[index];
 551                 break;
 552         default:
 553                 bref = NULL;
 554                 panic("hammer2_chain_get: unrecognized blockref type: %d",
 555                       parent->bref.type);
 556         }
 557
 558         /*
 559          * Allocate a chain structure representing the existing media
 560          * entry.  Thus the chain is *not* INITIAL and certainly not
 561          * MODIFIED (yet).
 562          */
 563         chain = hammer2_chain_alloc(hmp, bref);
 564
 565         /*
 566          * Link the chain into its parent.  Caller is expected to hold an
 567          * exclusive lock on the parent.
 568          */
 569         chain->parent = parent;
 570         chain->index = index;
 571         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, chain))
 572                 panic("hammer2_chain_link: collision");
 573         KKASSERT(parent->refs > 1);
 574         atomic_add_int(&parent->refs, 1);       /* for splay entry */
 575
 576         /*
 577          * Additional linkage for inodes.  Reuse the parent pointer to
 578          * find the parent directory.
 579          */
 580         if (bref->type == HAMMER2_BREF_TYPE_INODE) {
 581                 while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT)
 582                         parent = parent->parent;
 583                 if (parent->bref.type == HAMMER2_BREF_TYPE_INODE)
 584                         chain->u.ip->pip = parent->u.ip;
 585         }
 586
 587         /*
 588          * Our new chain structure has already been referenced and locked
 589          * but the lock code handles the I/O so call it to resolve the data.
 590          * Then release one of our two exclusive locks.
 591          *
 592          * If NOLOCK is set the release will release the one-and-only lock.
 593          */
 594         if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 595                 hammer2_chain_lock(hmp, chain);
 596         lockmgr(&chain->lk, LK_RELEASE);
 597
 598         return (chain);
 599 }
 600
 601 /*
 602  * Unlock and dereference a chain after use.  It is possible for this to
 603  * recurse up the chain.
 604  */
 605 void
 606 hammer2_chain_put(hammer2_mount_t *hmp, hammer2_chain_t *chain)
 607 {
 608         hammer2_chain_unlock(hmp, chain);
 609         hammer2_chain_drop(hmp, chain);
 610 }
 611
 612 /*
 613  * Locate any key between key_beg and key_end inclusive.  (*parentp)
 614  * typically points to an inode but can also point to a related indirect
 615  * block and this function will recurse upwards and find the inode again.
 616  *
 617  * WARNING!  THIS DOES NOT RETURN KEYS IN LOGICAL KEY ORDER!  ANY KEY
 618  *           WITHIN THE RANGE CAN BE RETURNED.  HOWEVER, AN ITERATION
 619  *           WHICH PICKS UP WHERE WE LEFT OFF WILL CONTINUE THE SCAN.
 620  *
 621  * (*parentp) must be exclusively locked and referenced and can be an inode
 622  * or an existing indirect block within the inode.
 623  *
 624  * On return (*parentp) will be modified to point at the deepest parent chain
 625  * element encountered during the search, as a helper for an insertion or
 626  * deletion.   The new (*parentp) will be locked and referenced and the old
 627  * will be unlocked and dereferenced (no change if they are both the same).
 628  *
 629  * The matching chain will be returned exclusively locked and referenced.
 630  *
 631  * NULL is returned if no match was found, but (*parentp) will still
 632  * potentially be adjusted.
 633  *
 634  * This function will also recurse up the chain if the key is not within the
 635  * current parent's range.  (*parentp) can never be set to NULL.  An iteration
 636  * can simply allow (*parentp) to float inside the loop.
 637  */
 638 hammer2_chain_t *
 639 hammer2_chain_lookup(hammer2_mount_t *hmp, hammer2_chain_t **parentp,
 640                      hammer2_key_t key_beg, hammer2_key_t key_end,
 641                      int flags)
 642 {
 643         hammer2_chain_t *parent;
 644         hammer2_chain_t *chain;
 645         hammer2_chain_t *tmp;
 646         hammer2_blockref_t *base;
 647         hammer2_blockref_t *bref;
 648         hammer2_key_t scan_beg;
 649         hammer2_key_t scan_end;
 650         int count = 0;
 651         int i;
 652
 653         /*
 654          * Recurse (*parentp) upward if necessary until the parent completely
 655          * encloses the key range or we hit the inode.
 656          */
 657         parent = *parentp;
 658         while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
 659                 scan_beg = parent->bref.key;
 660                 scan_end = scan_beg +
 661                            ((hammer2_key_t)1 << parent->bref.keybits) - 1;
 662                 if (key_beg >= scan_beg && key_end <= scan_end)
 663                         break;
 664                 hammer2_chain_unlock(hmp, parent);
 665                 parent = parent->parent;
 666                 hammer2_chain_ref(hmp, parent);         /* ref new parent */
 667                 hammer2_chain_lock(hmp, parent);        /* lock new parent */
 668                 hammer2_chain_drop(hmp, *parentp);      /* drop old parent */
 669                 *parentp = parent;                      /* new parent */
 670         }
 671
 672 again:
 673         /*
 674          * Locate the blockref array.  Currently we do a fully associative
 675          * search through the array.
 676          */
 677         switch(parent->bref.type) {
 678         case HAMMER2_BREF_TYPE_INODE:
 679                 /*
 680                  * Special shortcut for embedded data returns the inode
 681                  * itself.  Callers must detect this condition and access
 682                  * the embedded data (the strategy code does this for us).
 683                  *
 684                  * This is only applicable to regular files and softlinks.
 685                  */
 686                 if (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
 687                         hammer2_chain_ref(hmp, parent);
 688                         if ((flags & HAMMER2_LOOKUP_NOLOCK) == 0)
 689                                 hammer2_chain_lock(hmp, parent);
 690                         return (parent);
 691                 }
 692                 base = &parent->data->ipdata.u.blockset.blockref[0];
 693                 count = HAMMER2_SET_COUNT;
 694                 break;
 695         case HAMMER2_BREF_TYPE_INDIRECT:
 696                 if (parent->data == NULL)
 697                         panic("parent->data is NULL");
 698                 base = &parent->data->npdata.blockref[0];
 699                 count = HAMMER2_IND_COUNT;
 700                 break;
 701         case HAMMER2_BREF_TYPE_VOLUME:
 702                 base = &hmp->voldata.sroot_blockset.blockref[0];
 703                 count = HAMMER2_SET_COUNT;
 704                 break;
 705         default:
 706                 panic("hammer2_chain_lookup: unrecognized blockref type: %d",
 707                       parent->bref.type);
 708                 base = NULL;    /* safety */
 709                 count = 0;      /* safety */
 710         }
 711
 712         /*
 713          * If the element and key overlap we use the element.
 714          */
 715         bref = NULL;
 716         for (i = 0; i < count; ++i) {
 717                 tmp = hammer2_chain_find(hmp, parent, i);
 718                 bref = (tmp) ? &tmp->bref : &base[i];
 719                 if (bref->type == 0)
 720                         continue;
 721                 scan_beg = bref->key;
 722                 scan_end = scan_beg + ((hammer2_key_t)1 << bref->keybits) - 1;
 723                 if (key_beg <= scan_end && key_end >= scan_beg)
 724                         break;
 725         }
 726         if (i == count) {
 727                 if (key_beg == key_end)
 728                         return (NULL);
 729                 return (hammer2_chain_next(hmp, parentp, NULL,
 730                                            key_beg, key_end, flags));
 731         }
 732
 733         /*
 734          * Acquire the new chain element.  If the chain element is an
 735          * indirect block we must search recursively.
 736          */
 737         chain = hammer2_chain_get(hmp, parent, i, flags);
 738         if (chain == NULL)
 739                 return (NULL);
 740
 741         /*
 742          * If the chain element is an indirect block it becomes the new
 743          * parent and we loop on it.  We must fixup the chain we loop on
 744          * if the caller passed flags to us that aren't sufficient for our
 745          * needs.
 746          */
 747         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
 748                 hammer2_chain_put(hmp, parent);
 749                 *parentp = parent = chain;
 750                 if (flags & HAMMER2_LOOKUP_NOLOCK)
 751                         hammer2_chain_lock(hmp, chain);
 752                 goto again;
 753         }
 754
 755         /*
 756          * All done, return chain
 757          */
 758         return (chain);
 759 }
 760
 761 /*
 762  * After having issued a lookup we can iterate all matching keys.
 763  *
 764  * If chain is non-NULL we continue the iteration from just after it's index.
 765  *
 766  * If chain is NULL we assume the parent was exhausted and continue the
 767  * iteration at the next parent.
 768  */
 769 hammer2_chain_t *
 770 hammer2_chain_next(hammer2_mount_t *hmp, hammer2_chain_t **parentp,
 771                    hammer2_chain_t *chain,
 772                    hammer2_key_t key_beg, hammer2_key_t key_end,
 773                    int flags)
 774 {
 775         hammer2_chain_t *parent;
 776         hammer2_chain_t *tmp;
 777         hammer2_blockref_t *base;
 778         hammer2_blockref_t *bref;
 779         hammer2_key_t scan_beg;
 780         hammer2_key_t scan_end;
 781         int i;
 782         int count;
 783
 784         parent = *parentp;
 785
 786 again:
 787         /*
 788          * Calculate the next index and recalculate the parent if necessary.
 789          */
 790         if (chain) {
 791                 /*
 792                  * Continue iteration within current parent.  If not NULL
 793                  * the passed-in chain may or may not be locked, based on
 794                  * the LOOKUP_NOLOCK flag (passed in as returned from lookup
 795                  * or a prior next).
 796                  */
 797                 i = chain->index + 1;
 798                 if (flags & HAMMER2_LOOKUP_NOLOCK)
 799                         hammer2_chain_drop(hmp, chain);
 800                 else
 801                         hammer2_chain_put(hmp, chain);
 802
 803                 /*
 804                  * Any scan where the lookup returned degenerate data embedded
 805                  * in the inode has an invalid index and must terminate.
 806                  */
 807                 if (chain == parent)
 808                         return(NULL);
 809                 chain = NULL;
 810         } else if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT) {
 811                 /*
 812                  * We reached the end of the iteration.
 813                  */
 814                 return (NULL);
 815         } else {
 816                 /*
 817                  * Continue iteration with next parent unless the current
 818                  * parent covers the range.
 819                  */
 820                 hammer2_chain_t *nparent;
 821
 822                 if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT)
 823                         return (NULL);
 824
 825                 scan_beg = parent->bref.key;
 826                 scan_end = scan_beg +
 827                             ((hammer2_key_t)1 << parent->bref.keybits) - 1;
 828                 if (key_beg >= scan_beg && key_end <= scan_end)
 829                         return (NULL);
 830
 831                 i = parent->index + 1;
 832                 nparent = parent->parent;
 833                 hammer2_chain_ref(hmp, nparent);        /* ref new parent */
 834                 hammer2_chain_unlock(hmp, parent);
 835                 hammer2_chain_lock(hmp, nparent);       /* lock new parent */
 836                 hammer2_chain_drop(hmp, parent);        /* drop old parent */
 837                 *parentp = parent = nparent;
 838         }
 839
 840 again2:
 841         /*
 842          * Locate the blockref array.  Currently we do a fully associative
 843          * search through the array.
 844          */
 845         switch(parent->bref.type) {
 846         case HAMMER2_BREF_TYPE_INODE:
 847                 base = &parent->data->ipdata.u.blockset.blockref[0];
 848                 count = HAMMER2_SET_COUNT;
 849                 break;
 850         case HAMMER2_BREF_TYPE_INDIRECT:
 851                 base = &parent->data->npdata.blockref[0];
 852                 count = HAMMER2_IND_COUNT;
 853                 break;
 854         case HAMMER2_BREF_TYPE_VOLUME:
 855                 base = &hmp->voldata.sroot_blockset.blockref[0];
 856                 count = HAMMER2_SET_COUNT;
 857                 break;
 858         default:
 859                 panic("hammer2_chain_next: unrecognized blockref type: %d",
 860                       parent->bref.type);
 861                 base = NULL;    /* safety */
 862                 count = 0;      /* safety */
 863                 break;
 864         }
 865         KKASSERT(i <= count);
 866
 867         /*
 868          * Look for the key.  If we are unable to find a match and an exact
 869          * match was requested we return NULL.  If a range was requested we
 870          * run hammer2_chain_next() to iterate.
 871          */
 872         bref = NULL;
 873         while (i < count) {
 874                 tmp = hammer2_chain_find(hmp, parent, i);
 875                 bref = (tmp) ? &tmp->bref : &base[i];
 876                 if (bref->type == 0) {
 877                         ++i;
 878                         continue;
 879                 }
 880                 scan_beg = bref->key;
 881                 scan_end = scan_beg + ((hammer2_key_t)1 << bref->keybits) - 1;
 882                 if (key_beg <= scan_end && key_end >= scan_beg)
 883                         break;
 884                 ++i;
 885         }
 886
 887         /*
 888          * If we couldn't find a match recurse up a parent to continue the
 889          * search.
 890          */
 891         if (i == count)
 892                 goto again;
 893
 894         /*
 895          * Acquire the new chain element.  If the chain element is an
 896          * indirect block we must search recursively.
 897          */
 898         chain = hammer2_chain_get(hmp, parent, i, flags);
 899         if (chain == NULL)
 900                 return (NULL);
 901
 902         /*
 903          * If the chain element is an indirect block it becomes the new
 904          * parent and we loop on it.  We may have to lock the chain when
 905          * cycling it in as the new parent as it will not be locked if the
 906          * caller passed NOLOCK.
 907          */
 908         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT) {
 909                 hammer2_chain_put(hmp, parent);
 910                 *parentp = parent = chain;
 911                 if (flags & HAMMER2_LOOKUP_NOLOCK)
 912                         hammer2_chain_lock(hmp, chain);
 913                 i = 0;
 914                 goto again2;
 915         }
 916
 917         /*
 918          * All done, return chain
 919          */
 920         return (chain);
 921 }
 922
 923 /*
 924  * Create and return a new hammer2 system memory structure of the specified
 925  * key, type and size and insert it RELATIVE TO (PARENT).
 926  *
 927  * (parent) is typically either an inode or an indirect  block, acquired
 928  * acquired as a side effect of issuing a prior failed lookup.  parent
 929  * must be locked and held.  Do not pass the inode chain to this function
 930  * unless that is the chain returned by the failed lookup.
 931  *
 932  * Non-indirect types will automatically allocate indirect blocks as required
 933  * if the new item does not fit in the current (parent).
 934  *
 935  * Indirect types will move a portion of the existing blockref array in
 936  * (parent) into the new indirect type and then use one of the free slots
 937  * to emplace the new indirect type.
 938  *
 939  * A new locked, referenced chain element is returned of the specified type.
 940  * This element will also be marked as modified and contain a data area
 941  * ready for initialization.
 942  */
 943 hammer2_chain_t *
 944 hammer2_chain_create(hammer2_mount_t *hmp, hammer2_chain_t *parent,
 945                      hammer2_chain_t *chain,
 946                      hammer2_key_t key, int keybits, int type, size_t bytes)
 947 {
 948         hammer2_blockref_t dummy;
 949         hammer2_blockref_t *base;
 950         hammer2_blockref_t *bref;
 951         hammer2_chain_t dummy_chain;
 952         int unlock_parent = 0;
 953         int allocated = 0;
 954         int count;
 955         int i;
 956
 957         if (chain == NULL) {
 958                 /*
 959                  * First allocate media space and construct the dummy bref,
 960                  * then allocate the in-memory chain structure.
 961                  */
 962                 bzero(&dummy, sizeof(dummy));
 963                 dummy.type = type;
 964                 dummy.key = key;
 965                 dummy.keybits = keybits;
 966                 dummy.data_off = hammer2_freemap_bytes_to_radix(bytes);
 967                 chain = hammer2_chain_alloc(hmp, &dummy);
 968                 allocated = 1;
 969
 970                 /*
 971                  * We set the WAS_MODIFIED flag here so the chain gets
 972                  * marked as modified below.
 973                  */
 974                 chain->flags |= HAMMER2_CHAIN_INITIAL |
 975                                 HAMMER2_CHAIN_WAS_MODIFIED;
 976
 977                 /*
 978                  * Recalculate bytes to reflect the actual media block
 979                  * allocation.
 980                  */
 981                 bytes = (hammer2_off_t)1 <<
 982                         (int)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
 983
 984                 switch(type) {
 985                 case HAMMER2_BREF_TYPE_VOLUME:
 986                         panic("hammer2_chain_create: called with volume type");
 987                         break;
 988                 case HAMMER2_BREF_TYPE_INODE:
 989                         KKASSERT(bytes == HAMMER2_INODE_BYTES);
 990                         chain->data = (void *)&chain->u.ip->ip_data;
 991                         break;
 992                 default:
 993                         /* leave chain->data NULL */
 994                         KKASSERT(chain->data == NULL);
 995                         break;
 996                 }
 997         } else {
 998                 /*
 999                  * Potentially update the chain's key/keybits, but it will
1000                  * only be marked modified if WAS_MODIFIED is set (if it
1001                  * was modified at the time of its removal during a rename).
1002                  */
1003                 chain->bref.key = key;
1004                 chain->bref.keybits = keybits;
1005         }
1006
1007 again:
1008         /*
1009          * Locate a free blockref in the parent's array
1010          */
1011         switch(parent->bref.type) {
1012         case HAMMER2_BREF_TYPE_INODE:
1013                 KKASSERT(parent->data != NULL);
1014                 base = &parent->data->ipdata.u.blockset.blockref[0];
1015                 count = HAMMER2_SET_COUNT;
1016                 break;
1017         case HAMMER2_BREF_TYPE_INDIRECT:
1018                 KKASSERT(parent->data != NULL);
1019                 base = &parent->data->npdata.blockref[0];
1020                 count = HAMMER2_IND_COUNT;
1021                 break;
1022         case HAMMER2_BREF_TYPE_VOLUME:
1023                 KKASSERT(parent->data != NULL);
1024                 base = &hmp->voldata.sroot_blockset.blockref[0];
1025                 count = HAMMER2_SET_COUNT;
1026                 break;
1027         default:
1028                 panic("hammer2_chain_create: unrecognized blockref type: %d",
1029                       parent->bref.type);
1030                 count = 0;
1031                 break;
1032         }
1033
1034         /*
1035          * Scan for an unallocated bref, also skipping any slots occupied
1036          * by in-memory chain elements that may not yet have been updated
1037          * in the parent's bref array.
1038          */
1039         bzero(&dummy_chain, sizeof(dummy_chain));
1040         bref = NULL;
1041         for (i = 0; i < count; ++i) {
1042                 bref = &base[i];
1043                 dummy_chain.index = i;
1044                 if (bref->type == 0 &&
1045                     SPLAY_FIND(hammer2_chain_splay,
1046                                &parent->shead, &dummy_chain) == NULL) {
1047                         break;
1048                 }
1049         }
1050
1051         /*
1052          * If no free blockref count be found we must create an indirect
1053          * block and move a number of blockrefs into it.  With the parent
1054          * locked we can safely lock each child in order to move it without
1055          * causing a deadlock.
1056          *
1057          * This may return the new indirect block or the old parent depending
1058          * on where the key falls.
1059          */
1060         if (i == count) {
1061                 hammer2_chain_t *nparent;
1062
1063                 nparent = hammer2_chain_create_indirect(hmp, parent,
1064                                                         key, keybits);
1065                 if (nparent == NULL) {
1066                         if (allocated)
1067                                 hammer2_chain_free(hmp, chain);
1068                         chain = NULL;
1069                         goto done;
1070                 }
1071                 if (parent != nparent) {
1072                         if (unlock_parent)
1073                                 hammer2_chain_put(hmp, parent);
1074                         parent = nparent;
1075                         unlock_parent = 1;
1076                 }
1077                 goto again;
1078         }
1079
1080         /*
1081          * Link the chain into its parent.
1082          */
1083         if (chain->parent != NULL)
1084                 panic("hammer2: hammer2_chain_create: chain already connected");
1085         KKASSERT(chain->parent == NULL);
1086         chain->parent = parent;
1087         chain->index = i;
1088         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, chain))
1089                 panic("hammer2_chain_link: collision");
1090         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
1091         KKASSERT(parent->refs > 1);
1092         atomic_add_int(&parent->refs, 1);
1093
1094         /*
1095          * Additional linkage for inodes.  Reuse the parent pointer to
1096          * find the parent directory.
1097          */
1098         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1099                 hammer2_chain_t *scan = parent;
1100                 while (scan->bref.type == HAMMER2_BREF_TYPE_INDIRECT)
1101                         scan = scan->parent;
1102                 if (scan->bref.type == HAMMER2_BREF_TYPE_INODE)
1103                         chain->u.ip->pip = scan->u.ip;
1104         }
1105
1106         /*
1107          * Mark the newly created or previously disconnected chain element
1108          * as modified and fully resolve the chain->data pointer.  The
1109          * WAS_MODIFIED bit will be set in both cases.
1110          *
1111          * Chain elements with embedded data will not issue I/O at this time.
1112          * A new block will be allocated for the buffer but not instantiated.
1113          *
1114          * Chain elements which do not use embedded data will allocate
1115          * the new block AND instantiate its buffer cache buffer, pointing
1116          * the data at the bp.
1117          */
1118         if (chain->flags & HAMMER2_CHAIN_WAS_MODIFIED) {
1119                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_WAS_MODIFIED);
1120                 hammer2_chain_modify(hmp, chain);
1121         }
1122
1123 done:
1124         if (unlock_parent)
1125                 hammer2_chain_put(hmp, parent);
1126         return (chain);
1127 }
1128
1129 /*
1130  * Create an indirect block that covers one or more of the elements in the
1131  * current parent.  Either returns the existing parent with no locking or
1132  * ref changes or returns the new indirect block locked and referenced,
1133  * depending on what the specified key falls into.
1134  *
1135  * The key/keybits for the indirect mode only needs to follow three rules:
1136  *
1137  * (1) That all elements underneath it fit within its key space and
1138  *
1139  * (2) That all elements outside it are outside its key space.
1140  *
1141  * (3) When creating the new indirect block any elements in the current
1142  *     parent that fit within the new indirect block's keyspace must be
1143  *     moved into the new indirect block.
1144  *
1145  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
1146  *     keyspace the the current parent, but lookup/iteration rules will
1147  *     ensure (and must ensure) that rule (2) for all parents leading up
1148  *     to the nearest inode or the root volume header is adhered to.  This
1149  *     is accomplished by always recursing through matching keyspaces in
1150  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
1151  *
1152  * The current implementation calculates the current worst-case keyspace by
1153  * iterating the current parent and then divides it into two halves, choosing
1154  * whichever half has the most elements (not necessarily the half containing
1155  * the requested key).
1156  *
1157  * We can also opt to use the half with the least number of elements.  This
1158  * causes lower-numbered keys (aka logical file offsets) to recurse through
1159  * fewer indirect blocks and higher-numbered keys to recurse through more.
1160  * This also has the risk of not moving enough elements to the new indirect
1161  * block and being forced to create several indirect blocks before the element
1162  * can be inserted.
1163  */
1164 static
1165 hammer2_chain_t *
1166 hammer2_chain_create_indirect(hammer2_mount_t *hmp, hammer2_chain_t *parent,
1167                               hammer2_key_t create_key, int create_bits)
1168 {
1169         hammer2_blockref_t *base;
1170         hammer2_blockref_t *bref;
1171         hammer2_chain_t *chain;
1172         hammer2_chain_t *ichain;
1173         hammer2_chain_t dummy;
1174         hammer2_key_t key = create_key;
1175         int keybits = create_bits;
1176         int locount = 0;
1177         int hicount = 0;
1178         int count;
1179         int i;
1180
1181         /*
1182          * Mark the parent modified so our base[] pointer remains valid
1183          * while we move entries.
1184          */
1185         hammer2_chain_modify(hmp, parent);
1186
1187         /*
1188          * Locate a free blockref in the parent's array
1189          */
1190         switch(parent->bref.type) {
1191         case HAMMER2_BREF_TYPE_INODE:
1192                 base = &parent->data->ipdata.u.blockset.blockref[0];
1193                 count = HAMMER2_SET_COUNT;
1194                 break;
1195         case HAMMER2_BREF_TYPE_INDIRECT:
1196                 base = &parent->data->npdata.blockref[0];
1197                 count = HAMMER2_IND_COUNT;
1198                 break;
1199         case HAMMER2_BREF_TYPE_VOLUME:
1200                 base = &hmp->voldata.sroot_blockset.blockref[0];
1201                 count = HAMMER2_SET_COUNT;
1202                 break;
1203         default:
1204                 panic("hammer2_chain_create_indirect: "
1205                       "unrecognized blockref type: %d",
1206                       parent->bref.type);
1207                 count = 0;
1208                 break;
1209         }
1210
1211         /*
1212          * Scan for an unallocated bref, also skipping any slots occupied
1213          * by in-memory chain elements that may not yet have been updated
1214          * in the parent's bref array.
1215          */
1216         bzero(&dummy, sizeof(dummy));
1217         for (i = 0; i < count; ++i) {
1218                 int nkeybits;
1219
1220                 bref = &base[i];
1221                 if (bref->type == 0) {
1222                         dummy.index = i;
1223                         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead,
1224                                            &dummy);
1225                         if (chain == NULL)
1226                                 continue;
1227                         bref = &chain->bref;
1228                 }
1229
1230                 /*
1231                  * Expand our calculated key range (key, keybits) to fit
1232                  * the scanned key.  nkeybits represents the full range
1233                  * that we will later cut in half (two halves @ nkeybits - 1).
1234                  */
1235                 nkeybits = keybits;
1236                 if (nkeybits < bref->keybits)
1237                         nkeybits = bref->keybits;
1238                 while ((~(((hammer2_key_t)1 << nkeybits) - 1) &
1239                         (key ^ bref->key)) != 0) {
1240                         ++nkeybits;
1241                 }
1242
1243                 /*
1244                  * If the new key range is larger we have to determine
1245                  * which side of the new key range the existing keys fall
1246                  * under by checking the high bit, then collapsing the
1247                  * locount into the hicount or vise-versa.
1248                  */
1249                 if (keybits != nkeybits) {
1250                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
1251                                 hicount += locount;
1252                                 locount = 0;
1253                         } else {
1254                                 locount += hicount;
1255                                 hicount = 0;
1256                         }
1257                         keybits = nkeybits;
1258                 }
1259
1260                 /*
1261                  * The newly scanned key will be in the lower half or the
1262                  * higher half of the (new) key range.
1263                  */
1264                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
1265                         ++hicount;
1266                 else
1267                         ++locount;
1268         }
1269
1270         /*
1271          * Adjust keybits to represent half of the full range calculated
1272          * above.
1273          */
1274         --keybits;
1275
1276         /*
1277          * Select whichever half contains the most elements.  Theoretically
1278          * we can select either side as long as it contains at least one
1279          * element (in order to ensure that a free slot is present to hold
1280          * the indirect block).
1281          */
1282         key &= ~(((hammer2_key_t)1 << keybits) - 1);
1283         if (hammer2_indirect_optimize) {
1284                 /*
1285                  * Insert node for least number of keys, this will arrange
1286                  * the first few blocks of a large file or the first few
1287                  * inodes in a directory with fewer indirect blocks when
1288                  * created linearly.
1289                  */
1290                 if (hicount < locount && hicount != 0)
1291                         key |= (hammer2_key_t)1 << keybits;
1292                 else
1293                         key &= ~(hammer2_key_t)1 << keybits;
1294         } else {
1295                 /*
1296                  * Insert node for most number of keys, best for heavily
1297                  * fragmented files.
1298                  */
1299                 if (hicount > locount)
1300                         key |= (hammer2_key_t)1 << keybits;
1301                 else
1302                         key &= ~(hammer2_key_t)1 << keybits;
1303         }
1304
1305         /*
1306          * Ok, create our new indirect block
1307          */
1308         dummy.bref.type = HAMMER2_BREF_TYPE_INDIRECT;
1309         dummy.bref.key = key;
1310         dummy.bref.keybits = keybits;
1311         dummy.bref.data_off = (hammer2_off_t)
1312                             hammer2_freemap_bytes_to_radix(HAMMER2_PBUFSIZE);
1313         ichain = hammer2_chain_alloc(hmp, &dummy.bref);
1314         ichain->flags |= HAMMER2_CHAIN_INITIAL;
1315
1316         /*
1317          * Iterate the original parent and move the matching brefs into
1318          * the new indirect block.
1319          */
1320         for (i = 0; i < count; ++i) {
1321                 /*
1322                  * For keying purposes access the bref from the media or
1323                  * from our in-memory cache.  In cases where the in-memory
1324                  * cache overrides the media the keyrefs will be the same
1325                  * anyway so we can avoid checking the cache when the media
1326                  * has a key.
1327                  */
1328                 bref = &base[i];
1329                 if (bref->type == 0) {
1330                         dummy.index = i;
1331                         chain = SPLAY_FIND(hammer2_chain_splay, &parent->shead,
1332                                            &dummy);
1333                         if (chain == NULL) {
1334                                 /*
1335                                  * Select index indirect block is placed in
1336                                  */
1337                                 if (ichain->index < 0)
1338                                         ichain->index = i;
1339                                 continue;
1340                         }
1341                         bref = &chain->bref;
1342                 }
1343
1344                 /*
1345                  * Skip keys not in the chosen half (low or high), only bit
1346                  * (keybits - 1) needs to be compared but for safety we
1347                  * will compare all msb bits plus that bit again.
1348                  */
1349                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
1350                     (key ^ bref->key)) != 0) {
1351                         continue;
1352                 }
1353
1354                 /*
1355                  * This element is being moved, its slot is available
1356                  * for our indirect block.
1357                  */
1358                 if (ichain->index < 0)
1359                         ichain->index = i;
1360
1361                 /*
1362                  * Load the new indirect block by acquiring or allocating
1363                  * the related chain entries, then simply move it to the
1364                  * new parent (ichain).
1365                  *
1366                  * Flagging the new chain entry MOVED will cause a flush
1367                  * to synchronize its block into the new indirect block.
1368                  * The chain is unlocked after being moved but needs to
1369                  * retain a reference for the MOVED state
1370                  *
1371                  * We must still set SUBMODIFIED in the parent but we do
1372                  * that after the loop.
1373                  *
1374                  * XXX we really need a lock here but we don't need the
1375                  *     data.  NODATA feature needed.
1376                  */
1377                 chain = hammer2_chain_get(hmp, parent, i,
1378                                           HAMMER2_LOOKUP_NOLOCK);
1379                 SPLAY_REMOVE(hammer2_chain_splay, &parent->shead, chain);
1380                 if (SPLAY_INSERT(hammer2_chain_splay, &ichain->shead, chain))
1381                         panic("hammer2_chain_create_indirect: collision");
1382                 chain->parent = ichain;
1383                 bzero(&base[i], sizeof(base[i]));
1384                 atomic_add_int(&parent->refs, -1);
1385                 atomic_add_int(&ichain->refs, 1);
1386                 if (chain->flags & HAMMER2_CHAIN_MOVED) {
1387                         /* We don't need the ref from the chain_get */
1388                         hammer2_chain_drop(hmp, chain);
1389                 } else {
1390                         /* MOVED bit inherits the ref from the chain_get */
1391                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
1392                 }
1393                 KKASSERT(parent->refs > 0);
1394                 chain = NULL;
1395         }
1396
1397         /*
1398          * Insert the new indirect block into the parent now that we've
1399          * cleared out some entries in the parent.  We calculated a good
1400          * insertion index in the loop above (ichain->index).
1401          */
1402         KKASSERT(ichain->index >= 0);
1403         if (SPLAY_INSERT(hammer2_chain_splay, &parent->shead, ichain))
1404                 panic("hammer2_chain_create_indirect: ichain insertion");
1405         ichain->parent = parent;
1406         atomic_add_int(&parent->refs, 1);
1407
1408         /*
1409          * Mark the new indirect block modified after insertion, which
1410          * will propagate up through parent all the way to the root and
1411          * also allocate the physical block in ichain for our caller.
1412          *
1413          * We have to set SUBMODIFIED in ichain's flags manually so the
1414          * flusher knows it has to recurse through it to get to all of
1415          * our moved blocks.
1416          */
1417         hammer2_chain_modify(hmp, ichain);
1418         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_SUBMODIFIED);
1419
1420         /*
1421          * Figure out what to return.
1422          */
1423         if (create_bits >= keybits) {
1424                 /*
1425                  * Key being created is way outside the key range,
1426                  * return the original parent.
1427                  */
1428                 hammer2_chain_put(hmp, ichain);
1429         } else if (~(((hammer2_key_t)1 << keybits) - 1) &
1430                    (create_key ^ key)) {
1431                 /*
1432                  * Key being created is outside the key range,
1433                  * return the original parent.
1434                  */
1435                 hammer2_chain_put(hmp, ichain);
1436         } else {
1437                 /*
1438                  * Otherwise its in the range, return the new parent.
1439                  */
1440                 parent = ichain;
1441         }
1442
1443         return(parent);
1444 }
1445
1446 /*
1447  * Physically delete the specified chain element.  Note that inodes with
1448  * open descriptors should not be deleted (as with other filesystems) until
1449  * the last open descriptor is closed.
1450  *
1451  * This routine will remove the chain element from its parent and potentially
1452  * also recurse upward and delete indirect blocks which become empty as a
1453  * side effect.
1454  *
1455  * The caller must pass a pointer to the chain's parent, also locked and
1456  * referenced.  (*parentp) will be modified in a manner similar to a lookup
1457  * or iteration when indirect blocks are also deleted as a side effect.
1458  */
1459 void
1460 hammer2_chain_delete(hammer2_mount_t *hmp, hammer2_chain_t *parent,
1461                      hammer2_chain_t *chain)
1462 {
1463         hammer2_blockref_t *base;
1464         int count;
1465
1466         if (chain->parent != parent)
1467                 panic("hammer2_chain_delete: parent mismatch");
1468
1469         /*
1470          * Mark the parent modified so our base[] pointer remains valid
1471          * while we move entries.
1472          *
1473          * Calculate the blockref reference in the parent
1474          */
1475         hammer2_chain_modify(hmp, parent);
1476
1477         switch(parent->bref.type) {
1478         case HAMMER2_BREF_TYPE_INODE:
1479                 base = &parent->data->ipdata.u.blockset.blockref[0];
1480                 count = HAMMER2_SET_COUNT;
1481                 break;
1482         case HAMMER2_BREF_TYPE_INDIRECT:
1483                 base = &parent->data->npdata.blockref[0];
1484                 count = HAMMER2_IND_COUNT;
1485                 break;
1486         case HAMMER2_BREF_TYPE_VOLUME:
1487                 base = &hmp->voldata.sroot_blockset.blockref[0];
1488                 count = HAMMER2_SET_COUNT;
1489                 break;
1490         default:
1491                 panic("hammer2_chain_delete: unrecognized blockref type: %d",
1492                       parent->bref.type);
1493                 count = 0;
1494                 break;
1495         }
1496
1497         /*
1498          * Disconnect the bref in the parent, remove the chain, and
1499          * disconnect in-memory fields from the parent.
1500          */
1501         KKASSERT(chain->index >= 0 && chain->index < count);
1502         base += chain->index;
1503         bzero(base, sizeof(*base));
1504
1505         SPLAY_REMOVE(hammer2_chain_splay, &parent->shead, chain);
1506         atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
1507         atomic_add_int(&parent->refs, -1);      /* for splay entry */
1508         chain->index = -1;
1509
1510         chain->parent = NULL;
1511         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
1512                 chain->u.ip->pip = NULL;
1513
1514         /*
1515          * Nobody references the underlying object any more so we can
1516          * clear any pending modification(s) on it.  This can theoretically
1517          * recurse downward but even just clearing the bit on this item
1518          * will effectively recurse if someone is doing a rm -rf and greatly
1519          * reduce the I/O required.
1520          *
1521          * The MODIFIED1 bit is cleared but we have to remember the old state
1522          * in case this deletion is related to a rename.  The ref on the
1523          * chain is shared by both modified flags.
1524          */
1525         if (chain->flags & HAMMER2_CHAIN_MODIFIED1) {
1526                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
1527                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_WAS_MODIFIED);
1528                 if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
1529                         hammer2_chain_drop(hmp, chain);
1530         }
1531 }
1532
1533 /*
1534  * Recursively flush the specified chain.  The chain is locked and
1535  * referenced by the caller and will remain so on return.
1536  *
1537  * This cannot be called with the volume header's vchain (yet).
1538  *
1539  * PASS1 - clear the MODIFIED1 bit (and set the MODIFIED2 bit XXX)
1540  *
1541  */
1542 static void
1543 hammer2_chain_flush_pass1(hammer2_mount_t *hmp, hammer2_chain_t *chain)
1544 {
1545         /*
1546          * Flush any children of this chain entry.
1547          */
1548         if (chain->flags & HAMMER2_CHAIN_SUBMODIFIED) {
1549                 hammer2_blockref_t *base;
1550                 hammer2_chain_t *scan;
1551                 hammer2_chain_t *next;
1552                 int count;
1553                 int submodified = 0;
1554
1555                 /*
1556                  * Modifications to the children will propagate up, forcing
1557                  * us to become modified and copy-on-write too.
1558                  *
1559                  * Clear SUBMODIFIED now, races during the flush will re-set
1560                  * it.
1561                  */
1562                 hammer2_chain_modify(hmp, chain);
1563                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_SUBMODIFIED);
1564
1565                 /*
1566                  * The blockref in the parent's array must be repointed at
1567                  * the new block allocated by the child after its flush.
1568                  *
1569                  * Calculate the base of the array.
1570                  */
1571                 switch(chain->bref.type) {
1572                 case HAMMER2_BREF_TYPE_INODE:
1573                         KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
1574                         base = &chain->data->ipdata.u.blockset.blockref[0];
1575                         count = HAMMER2_SET_COUNT;
1576                         break;
1577                 case HAMMER2_BREF_TYPE_INDIRECT:
1578                         base = &chain->data->npdata.blockref[0];
1579                         count = HAMMER2_IND_COUNT;
1580                         break;
1581                 case HAMMER2_BREF_TYPE_VOLUME:
1582                         KKASSERT(index >= 0 && index < HAMMER2_SET_COUNT);
1583                         base = &hmp->voldata.sroot_blockset.blockref[0];
1584                         count = HAMMER2_SET_COUNT;
1585                         break;
1586                 default:
1587                         base = NULL;
1588                         panic("hammer2_chain_get: unrecognized blockref type: %d",
1589                               chain->bref.type);
1590                 }
1591
1592                 /*
1593                  * Flush the children and update the blockrefs in the parent.
1594                  * Be careful of ripouts during the loop.
1595                  */
1596                 next = SPLAY_MIN(hammer2_chain_splay, &chain->shead);
1597                 while ((scan = next) != NULL) {
1598                         next = SPLAY_NEXT(hammer2_chain_splay, &chain->shead,
1599                                           scan);
1600                         if (scan->flags & (HAMMER2_CHAIN_SUBMODIFIED |
1601                                            HAMMER2_CHAIN_MODIFIED1 |
1602                                            HAMMER2_CHAIN_MOVED)) {
1603                                 hammer2_chain_ref(hmp, scan);
1604                                 hammer2_chain_lock(hmp, scan);
1605                                 hammer2_chain_flush_pass1(hmp, scan);
1606                                 if (scan->flags & (HAMMER2_CHAIN_SUBMODIFIED |
1607                                                    HAMMER2_CHAIN_MODIFIED1)) {
1608                                         submodified = 1;
1609                                         kprintf("x");
1610                                 } else {
1611                                         KKASSERT(scan->index < count);
1612                                         base[scan->index] = scan->bref;
1613                                         if (scan->flags & HAMMER2_CHAIN_MOVED) {
1614                                                 atomic_clear_int(&scan->flags,
1615                                                          HAMMER2_CHAIN_MOVED);
1616                                                 hammer2_chain_drop(hmp, scan);
1617                                         }
1618                                 }
1619                                 hammer2_chain_put(hmp, scan);
1620                         }
1621                 }
1622                 if (submodified) {
1623                         atomic_set_int(&chain->flags,
1624                                        HAMMER2_CHAIN_SUBMODIFIED);
1625                 }
1626         }
1627
1628         /*
1629          * Flush this chain entry only if it is marked modified.
1630          */
1631         if ((chain->flags & HAMMER2_CHAIN_MODIFIED1) == 0)
1632                 return;
1633
1634         /*
1635          * Clear MODIFIED1 and set HAMMER2_CHAIN_MOVED.  The MODIFIED{1,2}
1636          * bits own a single parent ref and the MOVED bit owns its own
1637          * parent ref.
1638          */
1639         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED1);
1640         if (chain->flags & HAMMER2_CHAIN_MOVED) {
1641                 if ((chain->flags & HAMMER2_CHAIN_MODIFIED2) == 0)
1642                         hammer2_chain_drop(hmp, chain);
1643         } else {
1644                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
1645                 if (chain->flags & HAMMER2_CHAIN_MODIFIED2)
1646                         hammer2_chain_ref(hmp, chain);
1647         }
1648
1649         /*
1650          * If this is part of a recursive flush we can go ahead and write
1651          * out the buffer cache buffer and pass a new bref back up the chain.
1652          *
1653          * This will never be a volume header.
1654          */
1655         if (chain != &hmp->vchain) {
1656                 hammer2_blockref_t *bref;
1657                 hammer2_off_t off_hi;
1658                 struct buf *bp;
1659                 size_t off_lo;
1660                 size_t bytes;
1661                 int error;
1662
1663                 KKASSERT(chain->data != NULL);
1664                 bref = &chain->bref;
1665
1666                 off_hi = bref->data_off & HAMMER2_OFF_MASK_HI;
1667                 off_lo = (size_t)bref->data_off & HAMMER2_OFF_MASK_LO;
1668                 bytes = 1 << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
1669                 KKASSERT(off_hi != 0);  /* not the root volume header */
1670
1671                 if (chain->bp) {
1672                         /*
1673                          * The data is mapped directly to the bp.  Dirty the
1674                          * bp so it gets flushed out by the kernel later on.
1675                          */
1676                         bdirty(chain->bp);
1677                 } else {
1678                         /*
1679                          * The data is embedded, we have to acquire the
1680                          * buffer cache buffer and copy the data into it.
1681                          */
1682                         bp = NULL;
1683                         error = bread(hmp->devvp, off_hi,
1684                                       HAMMER2_PBUFSIZE, &bp);
1685                         KKASSERT(error == 0); /* XXX */
1686
1687                         /*
1688                          * Copy the data to the buffer, mark the buffer
1689                          * dirty, and convert the chain to unmodified.
1690                          */
1691                         bcopy(chain->data, (char *)bp->b_data + off_lo, bytes);
1692                         bdwrite(bp);
1693                         bp = NULL;
1694
1695                         chain->bref.check.iscsi32.value =
1696                                         hammer2_icrc32(chain->data, bytes);
1697                 }
1698         }
1699         {
1700                 hammer2_blockref_t *bref;
1701
1702                 bref = &chain->bref;
1703
1704                 switch(bref->type) {
1705                 case HAMMER2_BREF_TYPE_VOLUME:
1706                         KKASSERT(chain->data != NULL);
1707                         KKASSERT(chain->bp == NULL);
1708
1709                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT1]=
1710                                 hammer2_icrc32(
1711                                         (char *)&hmp->voldata +
1712                                          HAMMER2_VOLUME_ICRC1_OFF,
1713                                         HAMMER2_VOLUME_ICRC1_SIZE);
1714                         hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT0]=
1715                                 hammer2_icrc32(
1716                                         (char *)&hmp->voldata +
1717                                          HAMMER2_VOLUME_ICRC0_OFF,
1718                                         HAMMER2_VOLUME_ICRC0_SIZE);
1719                         hmp->voldata.icrc_volheader =
1720                                 hammer2_icrc32(
1721                                         (char *)&hmp->voldata +
1722                                          HAMMER2_VOLUME_ICRCVH_OFF,
1723                                         HAMMER2_VOLUME_ICRCVH_SIZE);
1724                         break;
1725                 }
1726         }
1727 }
1728
1729 #if 0
1730 /*
1731  * PASS2 - not yet implemented (should be called only with the root chain?)
1732  */
1733 static void
1734 hammer2_chain_flush_pass2(hammer2_mount_t *hmp, hammer2_chain_t *chain)
1735 {
1736 }
1737 #endif
1738
1739 void
1740 hammer2_chain_flush(hammer2_mount_t *hmp, hammer2_chain_t *chain)
1741 {
1742         hammer2_chain_flush_pass1(hmp, chain);
1743 }