sys/vfs/hammer2: Test bref type HAMMER2_BREF_TYPE_EMPTY instead 0
[dragonfly.git] / sys / vfs / hammer2 / hammer2_bulkfree.c
1 /*
2  * Copyright (c) 2013-2018 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  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/fcntl.h>
38 #include <sys/buf.h>
39 #include <sys/proc.h>
40 #include <sys/namei.h>
41 #include <sys/mount.h>
42 #include <sys/vnode.h>
43 #include <sys/mountctl.h>
44 #include <vm/vm_kern.h>
45 #include <vm/vm_extern.h>
46
47 #include "hammer2.h"
48
49 /*
50  * XXX I made a mistake and made the reserved area begin at each LEVEL1 zone,
51  *     which is on a 1GB demark.  This will eat a little more space but for
52  *     now we retain compatibility and make FMZONEBASE every 1GB
53  */
54 #define H2FMZONEBASE(key)       ((key) & ~HAMMER2_FREEMAP_LEVEL1_MASK)
55 #define H2FMBASE(key, radix)    ((key) & ~(((hammer2_off_t)1 << (radix)) - 1))
56 #define H2FMSHIFT(radix)        ((hammer2_off_t)1 << (radix))
57
58 /*
59  * breadth-first search
60  */
61 typedef struct hammer2_chain_save {
62         TAILQ_ENTRY(hammer2_chain_save) entry;
63         hammer2_chain_t *chain;
64         int pri;
65 } hammer2_chain_save_t;
66
67 TAILQ_HEAD(hammer2_chain_save_list, hammer2_chain_save);
68 typedef struct hammer2_chain_save_list hammer2_chain_save_list_t;
69
70 typedef struct hammer2_bulkfree_info {
71         hammer2_dev_t           *hmp;
72         kmem_anon_desc_t        kp;
73         hammer2_off_t           sbase;          /* sub-loop iteration */
74         hammer2_off_t           sstop;
75         hammer2_bmap_data_t     *bmap;
76         int                     depth;
77         long                    count_10_00;    /* staged->free      */
78         long                    count_11_10;    /* allocated->staged */
79         long                    count_00_11;    /* (should not happen) */
80         long                    count_01_11;    /* (should not happen) */
81         long                    count_10_11;    /* staged->allocated */
82         long                    count_l0cleans;
83         long                    count_linadjusts;
84         long                    count_inodes_scanned;
85         long                    count_dirents_scanned;
86         long                    count_dedup_factor;
87         long                    count_bytes_scanned;
88         long                    count_chains_scanned;
89         long                    count_chains_reported;
90         long                    bulkfree_calls;
91         int                     bulkfree_ticks;
92         hammer2_off_t           adj_free;
93         hammer2_tid_t           mtid;
94         hammer2_tid_t           saved_mirror_tid;
95         time_t                  save_time;
96         hammer2_chain_save_list_t list;
97         hammer2_dedup_t         *dedup;
98         int                     pri;
99 } hammer2_bulkfree_info_t;
100
101 static int h2_bulkfree_test(hammer2_bulkfree_info_t *info,
102                         hammer2_blockref_t *bref, int pri);
103
104 /*
105  * General bulk scan function with callback.  Called with a referenced
106  * but UNLOCKED parent.  The parent is returned in the same state.
107  */
108 static
109 int
110 hammer2_bulk_scan(hammer2_chain_t *parent,
111                   int (*func)(hammer2_bulkfree_info_t *info,
112                               hammer2_blockref_t *bref),
113                   hammer2_bulkfree_info_t *info)
114 {
115         hammer2_blockref_t bref;
116         hammer2_chain_t *chain;
117         int first = 1;
118         int rup_error;
119         int error;
120
121         ++info->pri;
122
123         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS |
124                                    HAMMER2_RESOLVE_SHARED);
125         chain = NULL;
126         rup_error = 0;
127         error = 0;
128
129         /*
130          * Generally loop on the contents if we have not been flagged
131          * for abort.
132          *
133          * Remember that these chains are completely isolated from
134          * the frontend, so we can release locks temporarily without
135          * imploding.
136          */
137         for (;;) {
138                 error |= hammer2_chain_scan(parent, &chain, &bref, &first,
139                                             HAMMER2_LOOKUP_NODATA |
140                                             HAMMER2_LOOKUP_SHARED);
141
142                 /*
143                  * Handle EOF or other error at current level.  This stops
144                  * the bulkfree scan.
145                  */
146                 if (error)
147                         break;
148
149                 /*
150                  * Account for dirents before thre data_off test, since most
151                  * dirents do not need a data reference.
152                  */
153                 if (bref.type == HAMMER2_BREF_TYPE_DIRENT)
154                         ++info->count_dirents_scanned;
155
156                 /*
157                  * Ignore brefs without data (typically dirents)
158                  */
159                 if ((bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0)
160                         continue;
161
162                 /*
163                  * Process bref, chain is only non-NULL if the bref
164                  * might be recursable (its possible that we sometimes get
165                  * a non-NULL chain where the bref cannot be recursed).
166                  */
167                 ++info->pri;
168                 if (h2_bulkfree_test(info, &bref, 1))
169                         continue;
170
171                 if (bref.type == HAMMER2_BREF_TYPE_INODE)
172                         ++info->count_inodes_scanned;
173
174                 error |= func(info, &bref);
175                 if (error)
176                         break;
177
178                 /*
179                  * A non-null chain is always returned if it is
180                  * recursive, otherwise a non-null chain might be
181                  * returned but usually is not when not recursive.
182                  */
183                 if (chain == NULL)
184                         continue;
185
186                 if (chain) {
187                         info->count_bytes_scanned += chain->bytes;
188                         ++info->count_chains_scanned;
189
190                         if (info->count_chains_scanned >=
191                             info->count_chains_reported + 1000000 ||
192                             (info->count_chains_scanned < 1000000 &&
193                              info->count_chains_scanned >=
194                              info->count_chains_reported + 100000)) {
195                                 kprintf(" chains %-7ld inodes %-7ld "
196                                         "dirents %-7ld bytes %5ldMB\n",
197                                         info->count_chains_scanned,
198                                         info->count_inodes_scanned,
199                                         info->count_dirents_scanned,
200                                         info->count_bytes_scanned / 1000000);
201                                 info->count_chains_reported =
202                                         info->count_chains_scanned;
203                         }
204                 }
205
206
207                 /*
208                  * Else check type and setup depth-first scan.
209                  *
210                  * Account for bytes actually read.
211                  */
212                 switch(chain->bref.type) {
213                 case HAMMER2_BREF_TYPE_INODE:
214                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
215                 case HAMMER2_BREF_TYPE_INDIRECT:
216                 case HAMMER2_BREF_TYPE_VOLUME:
217                 case HAMMER2_BREF_TYPE_FREEMAP:
218                         ++info->depth;
219                         if (info->depth > 16) {
220                                 hammer2_chain_save_t *save;
221                                 save = kmalloc(sizeof(*save), M_HAMMER2,
222                                                M_WAITOK | M_ZERO);
223                                 save->chain = chain;
224                                 hammer2_chain_ref(chain);
225                                 TAILQ_INSERT_TAIL(&info->list, save, entry);
226
227                                 /* guess */
228                                 info->pri += 10;
229                         } else {
230                                 int savepri = info->pri;
231
232                                 hammer2_chain_unlock(chain);
233                                 hammer2_chain_unlock(parent);
234                                 info->pri = 0;
235                                 rup_error |=
236                                         hammer2_bulk_scan(chain, func, info);
237                                 info->pri += savepri;
238                                 hammer2_chain_lock(parent,
239                                                    HAMMER2_RESOLVE_ALWAYS |
240                                                    HAMMER2_RESOLVE_SHARED);
241                                 hammer2_chain_lock(chain,
242                                                    HAMMER2_RESOLVE_ALWAYS |
243                                                    HAMMER2_RESOLVE_SHARED);
244                         }
245                         --info->depth;
246                         break;
247                 case HAMMER2_BREF_TYPE_DATA:
248                         break;
249                 default:
250                         /* does not recurse */
251                         break;
252                 }
253                 if (rup_error & HAMMER2_ERROR_ABORTED)
254                         break;
255         }
256         if (chain) {
257                 hammer2_chain_unlock(chain);
258                 hammer2_chain_drop(chain);
259         }
260
261         /*
262          * Save with higher pri now that we know what it is.
263          */
264         h2_bulkfree_test(info, &parent->bref, info->pri + 1);
265
266         hammer2_chain_unlock(parent);
267
268         return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
269 }
270
271 /*
272  * Bulkfree algorithm
273  *
274  * Repeat {
275  *      Chain flush (partial synchronization) XXX removed
276  *      Scan the whole topology - build in-memory freemap (mark 11)
277  *      Reconcile the in-memory freemap against the on-disk freemap.
278  *              ondisk xx -> ondisk 11 (if allocated)
279  *              ondisk 11 -> ondisk 10 (if free in-memory)
280  *              ondisk 10 -> ondisk 00 (if free in-memory) - on next pass
281  * }
282  *
283  * The topology scan may have to be performed multiple times to window
284  * freemaps which are too large to fit in kernel memory.
285  *
286  * Races are handled using a double-transition (11->10, 10->00).  The bulkfree
287  * scan snapshots the volume root's blockset and thus can run concurrent with
288  * normal operations, as long as a full flush is made between each pass to
289  * synchronize any modified chains (otherwise their blocks might be improperly
290  * freed).
291  *
292  * Temporary memory in multiples of 64KB is required to reconstruct the leaf
293  * hammer2_bmap_data blocks so they can later be compared against the live
294  * freemap.  Each 64KB block represents 128 x 16KB x 1024 = ~2 GB of storage.
295  * A 32MB save area thus represents around ~1 TB.  The temporary memory
296  * allocated can be specified.  If it is not sufficient multiple topology
297  * passes will be made.
298  */
299
300 /*
301  * Bulkfree callback info
302  */
303 static void hammer2_bulkfree_thread(void *arg __unused);
304 static void cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size);
305 static int h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo,
306                         hammer2_blockref_t *bref);
307 static int h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo);
308 static void h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
309                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
310                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base);
311
312 void
313 hammer2_bulkfree_init(hammer2_dev_t *hmp)
314 {
315         hammer2_thr_create(&hmp->bfthr, NULL, hmp,
316                            hmp->devrepname, -1, -1,
317                            hammer2_bulkfree_thread);
318 }
319
320 void
321 hammer2_bulkfree_uninit(hammer2_dev_t *hmp)
322 {
323         hammer2_thr_delete(&hmp->bfthr);
324 }
325
326 static void
327 hammer2_bulkfree_thread(void *arg)
328 {
329         hammer2_thread_t *thr = arg;
330         hammer2_ioc_bulkfree_t bfi;
331         uint32_t flags;
332
333         for (;;) {
334                 hammer2_thr_wait_any(thr,
335                                      HAMMER2_THREAD_STOP |
336                                      HAMMER2_THREAD_FREEZE |
337                                      HAMMER2_THREAD_UNFREEZE |
338                                      HAMMER2_THREAD_REMASTER,
339                                      hz * 60);
340
341                 flags = thr->flags;
342                 cpu_ccfence();
343                 if (flags & HAMMER2_THREAD_STOP)
344                         break;
345                 if (flags & HAMMER2_THREAD_FREEZE) {
346                         hammer2_thr_signal2(thr, HAMMER2_THREAD_FROZEN,
347                                                  HAMMER2_THREAD_FREEZE);
348                         continue;
349                 }
350                 if (flags & HAMMER2_THREAD_UNFREEZE) {
351                         hammer2_thr_signal2(thr, 0,
352                                                  HAMMER2_THREAD_FROZEN |
353                                                  HAMMER2_THREAD_UNFREEZE);
354                         continue;
355                 }
356                 if (flags & HAMMER2_THREAD_FROZEN)
357                         continue;
358                 if (flags & HAMMER2_THREAD_REMASTER) {
359                         hammer2_thr_signal2(thr, 0, HAMMER2_THREAD_REMASTER);
360                         bzero(&bfi, sizeof(bfi));
361                         bfi.size = 8192 * 1024;
362                         /* hammer2_bulkfree_pass(thr->hmp, &bfi); */
363                 }
364         }
365         thr->td = NULL;
366         hammer2_thr_signal(thr, HAMMER2_THREAD_STOPPED);
367         /* structure can go invalid at this point */
368 }
369
370 int
371 hammer2_bulkfree_pass(hammer2_dev_t *hmp, hammer2_chain_t *vchain,
372                       hammer2_ioc_bulkfree_t *bfi)
373 {
374         hammer2_bulkfree_info_t cbinfo;
375         hammer2_chain_save_t *save;
376         hammer2_off_t incr;
377         size_t size;
378         int error;
379
380         /*
381          * We have to clear the live dedup cache as it might have entries
382          * that are freeable as of now.  Any new entries in the dedup cache
383          * made after this point, even if they become freeable, will have
384          * previously been fully allocated and will be protected by the
385          * 2-stage bulkfree.
386          */
387         hammer2_dedup_clear(hmp);
388
389         /*
390          * Setup for free pass using the buffer size specified by the
391          * hammer2 utility, 32K-aligned.
392          */
393         bzero(&cbinfo, sizeof(cbinfo));
394         size = (bfi->size + HAMMER2_FREEMAP_LEVELN_PSIZE - 1) &
395                ~(size_t)(HAMMER2_FREEMAP_LEVELN_PSIZE - 1);
396
397         /*
398          * Cap at 1/4 physical memory (hammer2 utility will not normally
399          * ever specify a buffer this big, but leave the option available).
400          */
401         if (size > kmem_lim_size() * 1024 * 1024 / 4) {
402                 size = kmem_lim_size() * 1024 * 1024 / 4;
403                 kprintf("hammer2: Warning: capping bulkfree buffer at %jdM\n",
404                         (intmax_t)size / (1024 * 1024));
405         }
406
407 #define HAMMER2_FREEMAP_SIZEDIV \
408         (HAMMER2_FREEMAP_LEVEL1_SIZE / HAMMER2_FREEMAP_LEVELN_PSIZE)
409 #define HAMMER2_FREEMAP_SIZEMASK        (HAMMER2_FREEMAP_SIZEDIV - 1)
410
411         /*
412          * Cap at the size needed to cover the whole volume to avoid
413          * making an unnecessarily large allocation.
414          */
415         if (size > hmp->voldata.volu_size / HAMMER2_FREEMAP_SIZEDIV) {
416                 size = (hmp->voldata.volu_size + HAMMER2_FREEMAP_SIZEMASK) /
417                         HAMMER2_FREEMAP_SIZEDIV;
418         }
419
420         /*
421          * Minimum bitmap buffer size, then align to a LEVELN_PSIZE (32K)
422          * boundary.
423          */
424         if (size < 1024 * 1024)
425                 size = 1024 * 1024;
426         size = (size + HAMMER2_FREEMAP_LEVELN_PSIZE - 1) &
427                ~(size_t)(HAMMER2_FREEMAP_LEVELN_PSIZE - 1);
428
429         cbinfo.hmp = hmp;
430         cbinfo.bmap = kmem_alloc_swapbacked(&cbinfo.kp, size, VM_SUBSYS_HAMMER);
431         cbinfo.saved_mirror_tid = hmp->voldata.mirror_tid;
432
433         cbinfo.dedup = kmalloc(sizeof(*cbinfo.dedup) * HAMMER2_DEDUP_HEUR_SIZE,
434                                M_HAMMER2, M_WAITOK | M_ZERO);
435
436         kprintf("hammer2: bulkfree buf=%jdM\n",
437                 (intmax_t)size / (1024 * 1024));
438
439         /*
440          * Normalize start point to a 2GB boundary.  We operate on a
441          * 64KB leaf bitmap boundary which represents 2GB of storage.
442          */
443         cbinfo.sbase = bfi->sbase;
444         if (cbinfo.sbase > hmp->voldata.volu_size)
445                 cbinfo.sbase = hmp->voldata.volu_size;
446         cbinfo.sbase &= ~HAMMER2_FREEMAP_LEVEL1_MASK;
447         TAILQ_INIT(&cbinfo.list);
448
449         cbinfo.bulkfree_ticks = ticks;
450
451         /*
452          * Loop on a full meta-data scan as many times as required to
453          * get through all available storage.
454          */
455         error = 0;
456         while (cbinfo.sbase < hmp->voldata.volu_size) {
457                 /*
458                  * We have enough ram to represent (incr) bytes of storage.
459                  * Each 64KB of ram represents 2GB of storage.
460                  *
461                  * We must also clean out our de-duplication heuristic for
462                  * each (incr) bytes of storage, otherwise we wind up not
463                  * scanning meta-data for later areas of storage because
464                  * they had already been scanned in earlier areas of storage.
465                  * Since the ranging is different, we have to restart
466                  * the dedup heuristic too.
467                  */
468                 int allmedia;
469
470                 cbinfo_bmap_init(&cbinfo, size);
471                 bzero(cbinfo.dedup, sizeof(*cbinfo.dedup) *
472                                     HAMMER2_DEDUP_HEUR_SIZE);
473                 cbinfo.count_inodes_scanned = 0;
474                 cbinfo.count_dirents_scanned = 0;
475                 cbinfo.count_bytes_scanned = 0;
476                 cbinfo.count_chains_scanned = 0;
477                 cbinfo.count_chains_reported = 0;
478
479                 incr = size / HAMMER2_FREEMAP_LEVELN_PSIZE *
480                        HAMMER2_FREEMAP_LEVEL1_SIZE;
481                 if (hmp->voldata.volu_size - cbinfo.sbase <= incr) {
482                         cbinfo.sstop = hmp->voldata.volu_size;
483                         allmedia = 1;
484                 } else {
485                         cbinfo.sstop = cbinfo.sbase + incr;
486                         allmedia = 0;
487                 }
488                 kprintf("hammer2: pass %016jx-%016jx ",
489                         (intmax_t)cbinfo.sbase,
490                         (intmax_t)cbinfo.sstop);
491                 if (allmedia && cbinfo.sbase == 0)
492                         kprintf("(all media)\n");
493                 else if (allmedia)
494                         kprintf("(remaining media)\n");
495                 else
496                         kprintf("(%jdGB of media)\n",
497                                 (intmax_t)incr / (1024L*1024*1024));
498
499                 /*
500                  * Scan topology for stuff inside this range.
501                  *
502                  * NOTE - By not using a transaction the operation can
503                  *        run concurrent with the frontend as well as
504                  *        with flushes.
505                  *
506                  *        We cannot safely set a mtid without a transaction,
507                  *        and in fact we don't want to set one anyway.  We
508                  *        want the bulkfree to be passive and no interfere
509                  *        with crash recovery.
510                  */
511 #undef HAMMER2_BULKFREE_TRANS   /* undef - don't use transaction */
512 #ifdef HAMMER2_BULKFREE_TRANS
513                 hammer2_trans_init(hmp->spmp, 0);
514                 cbinfo.mtid = hammer2_trans_sub(hmp->spmp);
515 #else
516                 cbinfo.mtid = 0;
517 #endif
518                 cbinfo.pri = 0;
519                 error |= hammer2_bulk_scan(vchain, h2_bulkfree_callback,
520                                            &cbinfo);
521
522                 while ((save = TAILQ_FIRST(&cbinfo.list)) != NULL &&
523                        error == 0) {
524                         TAILQ_REMOVE(&cbinfo.list, save, entry);
525                         cbinfo.pri = 0;
526                         error |= hammer2_bulk_scan(save->chain,
527                                                    h2_bulkfree_callback,
528                                                    &cbinfo);
529                         hammer2_chain_drop(save->chain);
530                         kfree(save, M_HAMMER2);
531                 }
532                 while (save) {
533                         TAILQ_REMOVE(&cbinfo.list, save, entry);
534                         hammer2_chain_drop(save->chain);
535                         kfree(save, M_HAMMER2);
536                         save = TAILQ_FIRST(&cbinfo.list);
537                 }
538
539                 /*
540                  * If the complete scan succeeded we can synchronize our
541                  * in-memory freemap against live storage.  If an abort
542                  * occured we cannot safely synchronize our partially
543                  * filled-out in-memory freemap.
544                  */
545                 if (error) {
546                         kprintf("bulkfree lastdrop %d %d error=0x%04x\n",
547                                 vchain->refs, vchain->core.chain_count, error);
548                 } else {
549                         kprintf("bulkfree lastdrop %d %d\n",
550                                 vchain->refs, vchain->core.chain_count);
551
552                         error = h2_bulkfree_sync(&cbinfo);
553
554                         hammer2_voldata_lock(hmp);
555                         hammer2_voldata_modify(hmp);
556                         hmp->voldata.allocator_free += cbinfo.adj_free;
557                         hammer2_voldata_unlock(hmp);
558                 }
559
560                 /*
561                  * Cleanup for next loop.
562                  */
563 #ifdef HAMMER2_BULKFREE_TRANS
564                 hammer2_trans_done(hmp->spmp, 0);
565 #endif
566                 if (error)
567                         break;
568                 cbinfo.sbase = cbinfo.sstop;
569                 cbinfo.adj_free = 0;
570         }
571         kmem_free_swapbacked(&cbinfo.kp);
572         kfree(cbinfo.dedup, M_HAMMER2);
573         cbinfo.dedup = NULL;
574
575         bfi->sstop = cbinfo.sbase;
576
577         incr = bfi->sstop / (hmp->voldata.volu_size / 10000);
578         if (incr > 10000)
579                 incr = 10000;
580
581         kprintf("bulkfree pass statistics (%d.%02d%% storage processed):\n",
582                 (int)incr / 100,
583                 (int)incr % 100);
584
585         if (error) {
586                 kprintf("    bulkfree was aborted\n");
587         } else {
588                 kprintf("    transition->free   %ld\n", cbinfo.count_10_00);
589                 kprintf("    transition->staged %ld\n", cbinfo.count_11_10);
590                 kprintf("    ERR(00)->allocated %ld\n", cbinfo.count_00_11);
591                 kprintf("    ERR(01)->allocated %ld\n", cbinfo.count_01_11);
592                 kprintf("    staged->allocated  %ld\n", cbinfo.count_10_11);
593                 kprintf("    ~2MB segs cleaned  %ld\n", cbinfo.count_l0cleans);
594                 kprintf("    linear adjusts     %ld\n",
595                         cbinfo.count_linadjusts);
596                 kprintf("    dedup factor       %ld\n",
597                         cbinfo.count_dedup_factor);
598         }
599
600         return error;
601 }
602
603 static void
604 cbinfo_bmap_init(hammer2_bulkfree_info_t *cbinfo, size_t size)
605 {
606         hammer2_bmap_data_t *bmap = cbinfo->bmap;
607         hammer2_key_t key = cbinfo->sbase;
608         hammer2_key_t lokey;
609         hammer2_key_t hikey;
610
611         lokey = (cbinfo->hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
612                 ~HAMMER2_SEGMASK64;
613         hikey = cbinfo->hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
614
615         bzero(bmap, size);
616         while (size) {
617                 bzero(bmap, sizeof(*bmap));
618                 if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
619                         lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
620                 if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
621                         lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
622                 if (key < lokey || key >= hikey) {
623                         memset(bmap->bitmapq, -1,
624                                sizeof(bmap->bitmapq));
625                         bmap->avail = 0;
626                         bmap->linear = HAMMER2_SEGSIZE;
627                 } else {
628                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
629                 }
630                 size -= sizeof(*bmap);
631                 key += HAMMER2_FREEMAP_LEVEL0_SIZE;
632                 ++bmap;
633         }
634 }
635
636 static int
637 h2_bulkfree_callback(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref)
638 {
639         hammer2_bmap_data_t *bmap;
640         hammer2_off_t data_off;
641         uint16_t class;
642         size_t bytes;
643         int radix;
644
645         /*
646          * Check for signal and allow yield to userland during scan.
647          */
648         if (hammer2_signal_check(&cbinfo->save_time))
649                 return HAMMER2_ERROR_ABORTED;
650
651         /*
652          * Deal with kernel thread cpu or I/O hogging by limiting the
653          * number of chains scanned per second to hammer2_bulkfree_tps.
654          * Ignore leaf records (DIRENT and DATA), no per-record I/O is
655          * involved for those since we don't load their data.
656          */
657         if (bref->type != HAMMER2_BREF_TYPE_DATA &&
658             bref->type != HAMMER2_BREF_TYPE_DIRENT) {
659                 ++cbinfo->bulkfree_calls;
660                 if (cbinfo->bulkfree_calls > hammer2_bulkfree_tps) {
661                         int dticks = ticks - cbinfo->bulkfree_ticks;
662                         if (dticks < 0)
663                                 dticks = 0;
664                         if (dticks < hz) {
665                                 tsleep(&cbinfo->bulkfree_ticks, 0,
666                                        "h2bw", hz - dticks);
667                         }
668                         cbinfo->bulkfree_calls = 0;
669                         cbinfo->bulkfree_ticks = ticks;
670                 }
671         }
672
673         /*
674          * Calculate the data offset and determine if it is within
675          * the current freemap range being gathered.
676          */
677         data_off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
678         if (data_off < cbinfo->sbase || data_off >= cbinfo->sstop)
679                 return 0;
680         if (data_off < cbinfo->hmp->voldata.allocator_beg)
681                 return 0;
682         if (data_off >= cbinfo->hmp->voldata.volu_size)
683                 return 0;
684
685         /*
686          * Calculate the information needed to generate the in-memory
687          * freemap record.
688          *
689          * Hammer2 does not allow allocations to cross the L1 (2GB) boundary,
690          * it's a problem if it does.  (Or L0 (2MB) for that matter).
691          */
692         radix = (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
693         KKASSERT(radix != 0);
694         bytes = (size_t)1 << radix;
695         class = (bref->type << 8) | hammer2_devblkradix(radix);
696
697         if (data_off + bytes > cbinfo->sstop) {
698                 kprintf("hammer2_bulkfree_scan: illegal 2GB boundary "
699                         "%016jx %016jx/%d\n",
700                         (intmax_t)bref->data_off,
701                         (intmax_t)bref->key,
702                         bref->keybits);
703                 bytes = cbinfo->sstop - data_off;       /* XXX */
704         }
705
706         /*
707          * Convert to a storage offset relative to the beginning of the
708          * storage range we are collecting.  Then lookup the level0 bmap entry.
709          */
710         data_off -= cbinfo->sbase;
711         bmap = cbinfo->bmap + (data_off >> HAMMER2_FREEMAP_LEVEL0_RADIX);
712
713         /*
714          * Convert data_off to a bmap-relative value (~4MB storage range).
715          * Adjust linear, class, and avail.
716          *
717          * Hammer2 does not allow allocations to cross the L0 (4MB) boundary,
718          */
719         data_off &= HAMMER2_FREEMAP_LEVEL0_MASK;
720         if (data_off + bytes > HAMMER2_FREEMAP_LEVEL0_SIZE) {
721                 kprintf("hammer2_bulkfree_scan: illegal 4MB boundary "
722                         "%016jx %016jx/%d\n",
723                         (intmax_t)bref->data_off,
724                         (intmax_t)bref->key,
725                         bref->keybits);
726                 bytes = HAMMER2_FREEMAP_LEVEL0_SIZE - data_off;
727         }
728
729         if (bmap->class == 0) {
730                 bmap->class = class;
731                 bmap->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
732         }
733
734         /*
735          * NOTE: bmap->class does not have to match class.  Classification
736          *       is relaxed when free space is low, so some mixing can occur.
737          */
738 #if 0
739         /*
740          * XXX removed
741          */
742         if (bmap->class != class) {
743                 kprintf("hammer2_bulkfree_scan: illegal mixed class "
744                         "%016jx %016jx/%d (%04x vs %04x)\n",
745                         (intmax_t)bref->data_off,
746                         (intmax_t)bref->key,
747                         bref->keybits,
748                         class, bmap->class);
749         }
750 #endif
751
752         /*
753          * Just record the highest byte-granular offset for now.  Do not
754          * match against allocations which are in multiples of whole blocks.
755          *
756          * Make sure that any in-block linear offset at least covers the
757          * data range.  This can cause bmap->linear to become block-aligned.
758          */
759         if (bytes & HAMMER2_FREEMAP_BLOCK_MASK) {
760                 if (bmap->linear < (int32_t)data_off + (int32_t)bytes)
761                         bmap->linear = (int32_t)data_off + (int32_t)bytes;
762         } else if (bmap->linear >= (int32_t)data_off &&
763                    bmap->linear < (int32_t)data_off + (int32_t)bytes) {
764                 bmap->linear = (int32_t)data_off + (int32_t)bytes;
765         }
766
767         /*
768          * Adjust the hammer2_bitmap_t bitmap[HAMMER2_BMAP_ELEMENTS].
769          * 64-bit entries, 2 bits per entry, to code 11.
770          *
771          * NOTE: data_off mask to 524288, shift right by 14 (radix for 16384),
772          *       and multiply shift amount by 2 for sets of 2 bits.
773          *
774          * NOTE: The allocation can be smaller than HAMMER2_FREEMAP_BLOCK_SIZE.
775          *       also, data_off may not be FREEMAP_BLOCK_SIZE aligned.
776          */
777         while (bytes > 0) {
778                 hammer2_bitmap_t bmask;
779                 int bindex;
780
781                 bindex = (int)data_off >> (HAMMER2_FREEMAP_BLOCK_RADIX +
782                                            HAMMER2_BMAP_INDEX_RADIX);
783                 bmask = (hammer2_bitmap_t)3 <<
784                         ((((int)data_off & HAMMER2_BMAP_INDEX_MASK) >>
785                          HAMMER2_FREEMAP_BLOCK_RADIX) << 1);
786
787                 /*
788                  * NOTE! The (avail) calculation is bitmap-granular.  Multiple
789                  *       sub-granular records can wind up at the same bitmap
790                  *       position.
791                  */
792                 if ((bmap->bitmapq[bindex] & bmask) == 0) {
793                         if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE) {
794                                 bmap->avail -= HAMMER2_FREEMAP_BLOCK_SIZE;
795                         } else {
796                                 bmap->avail -= bytes;
797                         }
798                         bmap->bitmapq[bindex] |= bmask;
799                 }
800                 data_off += HAMMER2_FREEMAP_BLOCK_SIZE;
801                 if (bytes < HAMMER2_FREEMAP_BLOCK_SIZE)
802                         bytes = 0;
803                 else
804                         bytes -= HAMMER2_FREEMAP_BLOCK_SIZE;
805         }
806         return 0;
807 }
808
809 /*
810  * Synchronize the in-memory bitmap with the live freemap.  This is not a
811  * direct copy.  Instead the bitmaps must be compared:
812  *
813  *      In-memory       Live-freemap
814  *         00             11 -> 10      (do nothing if live modified)
815  *                        10 -> 00      (do nothing if live modified)
816  *         11             10 -> 11      handles race against live
817  *                        ** -> 11      nominally warn of corruption
818  * 
819  * We must also fixup the hints in HAMMER2_BREF_TYPE_FREEMAP_LEAF.
820  */
821 static int
822 h2_bulkfree_sync(hammer2_bulkfree_info_t *cbinfo)
823 {
824         hammer2_off_t data_off;
825         hammer2_key_t key;
826         hammer2_key_t key_dummy;
827         hammer2_bmap_data_t *bmap;
828         hammer2_bmap_data_t *live;
829         hammer2_chain_t *live_parent;
830         hammer2_chain_t *live_chain;
831         int bmapindex;
832         int error;
833
834         kprintf("hammer2_bulkfree - range ");
835
836         if (cbinfo->sbase < cbinfo->hmp->voldata.allocator_beg)
837                 kprintf("%016jx-",
838                         (intmax_t)cbinfo->hmp->voldata.allocator_beg);
839         else
840                 kprintf("%016jx-",
841                         (intmax_t)cbinfo->sbase);
842
843         if (cbinfo->sstop > cbinfo->hmp->voldata.volu_size)
844                 kprintf("%016jx\n",
845                         (intmax_t)cbinfo->hmp->voldata.volu_size);
846         else
847                 kprintf("%016jx\n",
848                         (intmax_t)cbinfo->sstop);
849                 
850         data_off = cbinfo->sbase;
851         bmap = cbinfo->bmap;
852
853         live_parent = &cbinfo->hmp->fchain;
854         hammer2_chain_ref(live_parent);
855         hammer2_chain_lock(live_parent, HAMMER2_RESOLVE_ALWAYS);
856         live_chain = NULL;
857         error = 0;
858
859         /*
860          * Iterate each hammer2_bmap_data_t line (128 bytes) managing
861          * 4MB of storage.
862          */
863         while (data_off < cbinfo->sstop) {
864                 /*
865                  * The freemap is not used below allocator_beg or beyond
866                  * volu_size.
867                  */
868
869                 if (data_off < cbinfo->hmp->voldata.allocator_beg)
870                         goto next;
871                 if (data_off >= cbinfo->hmp->voldata.volu_size)
872                         goto next;
873
874                 /*
875                  * Locate the freemap leaf on the live filesystem
876                  */
877                 key = (data_off & ~HAMMER2_FREEMAP_LEVEL1_MASK);
878
879                 if (live_chain == NULL || live_chain->bref.key != key) {
880                         if (live_chain) {
881                                 hammer2_chain_unlock(live_chain);
882                                 hammer2_chain_drop(live_chain);
883                         }
884                         live_chain = hammer2_chain_lookup(
885                                             &live_parent,
886                                             &key_dummy,
887                                             key,
888                                             key + HAMMER2_FREEMAP_LEVEL1_MASK,
889                                             &error,
890                                             HAMMER2_LOOKUP_ALWAYS);
891                         if (error) {
892                                 kprintf("hammer2_bulkfree: freemap lookup "
893                                         "error near %016jx, error %s\n",
894                                         (intmax_t)data_off,
895                                         hammer2_error_str(live_chain->error));
896                                 break;
897                         }
898                 }
899                 if (live_chain == NULL) {
900                         /*
901                          * XXX if we implement a full recovery mode we need
902                          * to create/recreate missing freemap chains if our
903                          * bmap has any allocated blocks.
904                          */
905                         if (bmap->class &&
906                             bmap->avail != HAMMER2_FREEMAP_LEVEL0_SIZE) {
907                                 kprintf("hammer2_bulkfree: cannot locate "
908                                         "live leaf for allocated data "
909                                         "near %016jx\n",
910                                         (intmax_t)data_off);
911                         }
912                         goto next;
913                 }
914                 if (live_chain->error) {
915                         kprintf("hammer2_bulkfree: unable to access freemap "
916                                 "near %016jx, error %s\n",
917                                 (intmax_t)data_off,
918                                 hammer2_error_str(live_chain->error));
919                         hammer2_chain_unlock(live_chain);
920                         hammer2_chain_drop(live_chain);
921                         live_chain = NULL;
922                         goto next;
923                 }
924
925                 bmapindex = (data_off & HAMMER2_FREEMAP_LEVEL1_MASK) >>
926                             HAMMER2_FREEMAP_LEVEL0_RADIX;
927                 live = &live_chain->data->bmdata[bmapindex];
928
929                 /*
930                  * Shortcut if the bitmaps match and the live linear
931                  * indicator is sane.  We can't do a perfect check of
932                  * live->linear because the only real requirement is that
933                  * if it is not block-aligned, that it not cover the space
934                  * within its current block which overlaps one of the data
935                  * ranges we scan.  We don't retain enough fine-grained
936                  * data in our scan to be able to set it exactly.
937                  *
938                  * TODO - we could shortcut this by testing that both
939                  * live->class and bmap->class are 0, and both avails are
940                  * set to HAMMER2_FREEMAP_LEVEL0_SIZE (4MB).
941                  */
942                 if (bcmp(live->bitmapq, bmap->bitmapq,
943                          sizeof(bmap->bitmapq)) == 0 &&
944                     live->linear >= bmap->linear) {
945                         goto next;
946                 }
947                 if (hammer2_debug & 1) {
948                         kprintf("live %016jx %04d.%04x (avail=%d)\n",
949                                 data_off, bmapindex, live->class, live->avail);
950                 }
951
952                 hammer2_chain_modify(live_chain, cbinfo->mtid, 0, 0);
953                 live_chain->bref.check.freemap.bigmask = -1;
954                 cbinfo->hmp->freemap_relaxed = 0;       /* reset heuristic */
955                 live = &live_chain->data->bmdata[bmapindex];
956
957                 h2_bulkfree_sync_adjust(cbinfo, data_off, live, bmap,
958                                         live_chain->bref.key +
959                                         bmapindex *
960                                         HAMMER2_FREEMAP_LEVEL0_SIZE);
961 next:
962                 data_off += HAMMER2_FREEMAP_LEVEL0_SIZE;
963                 ++bmap;
964         }
965         if (live_chain) {
966                 hammer2_chain_unlock(live_chain);
967                 hammer2_chain_drop(live_chain);
968         }
969         if (live_parent) {
970                 hammer2_chain_unlock(live_parent);
971                 hammer2_chain_drop(live_parent);
972         }
973         return error;
974 }
975
976 /*
977  * Merge the bulkfree bitmap against the existing bitmap.
978  */
979 static
980 void
981 h2_bulkfree_sync_adjust(hammer2_bulkfree_info_t *cbinfo,
982                         hammer2_off_t data_off, hammer2_bmap_data_t *live,
983                         hammer2_bmap_data_t *bmap, hammer2_key_t alloc_base)
984 {
985         int bindex;
986         int scount;
987         hammer2_off_t tmp_off;
988         hammer2_bitmap_t lmask;
989         hammer2_bitmap_t mmask;
990
991         tmp_off = data_off;
992
993         for (bindex = 0; bindex < HAMMER2_BMAP_ELEMENTS; ++bindex) {
994                 lmask = live->bitmapq[bindex];  /* live */
995                 mmask = bmap->bitmapq[bindex];  /* snapshotted bulkfree */
996                 if (lmask == mmask) {
997                         tmp_off += HAMMER2_BMAP_INDEX_SIZE;
998                         continue;
999                 }
1000
1001                 for (scount = 0;
1002                      scount < HAMMER2_BMAP_BITS_PER_ELEMENT;
1003                      scount += 2) {
1004                         if ((mmask & 3) == 0) {
1005                                 /*
1006                                  * in-memory 00         live 11 -> 10
1007                                  *                      live 10 -> 00
1008                                  *
1009                                  * Storage might be marked allocated or
1010                                  * staged and must be remarked staged or
1011                                  * free.
1012                                  */
1013                                 switch (lmask & 3) {
1014                                 case 0: /* 00 */
1015                                         break;
1016                                 case 1: /* 01 */
1017                                         kprintf("hammer2_bulkfree: cannot "
1018                                                 "transition m=00/l=01\n");
1019                                         break;
1020                                 case 2: /* 10 -> 00 */
1021                                         live->bitmapq[bindex] &=
1022                                             ~((hammer2_bitmap_t)2 << scount);
1023                                         live->avail +=
1024                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1025                                         if (live->avail >
1026                                             HAMMER2_FREEMAP_LEVEL0_SIZE) {
1027                                                 live->avail =
1028                                                     HAMMER2_FREEMAP_LEVEL0_SIZE;
1029                                         }
1030                                         cbinfo->adj_free +=
1031                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1032                                         ++cbinfo->count_10_00;
1033                                         hammer2_io_dedup_assert(
1034                                                 cbinfo->hmp,
1035                                                 tmp_off |
1036                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
1037                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
1038                                         break;
1039                                 case 3: /* 11 -> 10 */
1040                                         live->bitmapq[bindex] &=
1041                                             ~((hammer2_bitmap_t)1 << scount);
1042                                         ++cbinfo->count_11_10;
1043                                         hammer2_io_dedup_delete(
1044                                                 cbinfo->hmp,
1045                                                 HAMMER2_BREF_TYPE_DATA,
1046                                                 tmp_off |
1047                                                 HAMMER2_FREEMAP_BLOCK_RADIX,
1048                                                 HAMMER2_FREEMAP_BLOCK_SIZE);
1049                                         break;
1050                                 }
1051                         } else if ((mmask & 3) == 3) {
1052                                 /*
1053                                  * in-memory 11         live 10 -> 11
1054                                  *                      live ** -> 11
1055                                  *
1056                                  * Storage might be incorrectly marked free
1057                                  * or staged and must be remarked fully
1058                                  * allocated.
1059                                  */
1060                                 switch (lmask & 3) {
1061                                 case 0: /* 00 */
1062                                         ++cbinfo->count_00_11;
1063                                         cbinfo->adj_free -=
1064                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1065                                         live->avail -=
1066                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1067                                         if ((int32_t)live->avail < 0)
1068                                                 live->avail = 0;
1069                                         break;
1070                                 case 1: /* 01 */
1071                                         ++cbinfo->count_01_11;
1072                                         break;
1073                                 case 2: /* 10 -> 11 */
1074                                         ++cbinfo->count_10_11;
1075                                         break;
1076                                 case 3: /* 11 */
1077                                         break;
1078                                 }
1079                                 live->bitmapq[bindex] |=
1080                                         ((hammer2_bitmap_t)3 << scount);
1081                         }
1082                         mmask >>= 2;
1083                         lmask >>= 2;
1084                         tmp_off += HAMMER2_FREEMAP_BLOCK_SIZE;
1085                 }
1086         }
1087
1088         /*
1089          * Determine if the live bitmap is completely free and reset its
1090          * fields if so.  Otherwise check to see if we can reduce the linear
1091          * offset.
1092          */
1093         for (bindex = HAMMER2_BMAP_ELEMENTS - 1; bindex >= 0; --bindex) {
1094                 if (live->bitmapq[bindex] != 0)
1095                         break;
1096         }
1097         if (bindex < 0) {
1098                 /*
1099                  * Completely empty, reset entire segment
1100                  */
1101 #if 0
1102                 kprintf("hammer2: cleanseg %016jx.%04x (%d)\n",
1103                         alloc_base, live->class, live->avail);
1104 #endif
1105                 live->avail = HAMMER2_FREEMAP_LEVEL0_SIZE;
1106                 live->class = 0;
1107                 live->linear = 0;
1108                 ++cbinfo->count_l0cleans;
1109         } else if (bindex < 7) {
1110                 /*
1111                  * Partially full, bitmapq[bindex] != 0.  Our bulkfree pass
1112                  * does not record enough information to set live->linear
1113                  * exactly.
1114                  *
1115                  * NOTE: Setting live->linear to a sub-block (16K) boundary
1116                  *       forces the live code to iterate to the next fully
1117                  *       free block.  It does NOT mean that all blocks above
1118                  *       live->linear are available.
1119                  *
1120                  *       Setting live->linear to a fragmentary (less than
1121                  *       16K) boundary allows allocations to iterate within
1122                  *       that sub-block.
1123                  */
1124                 if (live->linear < bmap->linear &&
1125                     ((live->linear ^ bmap->linear) &
1126                      ~HAMMER2_FREEMAP_BLOCK_MASK) == 0) {
1127                         /*
1128                          * If greater than but still within the same
1129                          * sub-block as live we can adjust linear upward.
1130                          */
1131                         live->linear = bmap->linear;
1132                         ++cbinfo->count_linadjusts;
1133                 } else {
1134                         /*
1135                          * Otherwise adjust to the nearest higher or same
1136                          * sub-block boundary.  The live system may have
1137                          * bounced live->linear around so we cannot make any
1138                          * assumptions with regards to available fragmentary
1139                          * allocations.
1140                          */
1141                         live->linear =
1142                                 (bmap->linear + HAMMER2_FREEMAP_BLOCK_MASK) &
1143                                 ~HAMMER2_FREEMAP_BLOCK_MASK;
1144                         ++cbinfo->count_linadjusts;
1145                 }
1146         } else {
1147                 /*
1148                  * Completely full, effectively disable the linear iterator
1149                  */
1150                 live->linear = HAMMER2_SEGSIZE;
1151         }
1152
1153 #if 0
1154         if (bmap->class) {
1155                 kprintf("%016jx %04d.%04x (avail=%7d) "
1156                         "%08x %08x %08x %08x %08x %08x %08x %08x\n",
1157                         (intmax_t)data_off,
1158                         (int)((data_off &
1159                                HAMMER2_FREEMAP_LEVEL1_MASK) >>
1160                               HAMMER2_FREEMAP_LEVEL0_RADIX),
1161                         bmap->class,
1162                         bmap->avail,
1163                         bmap->bitmap[0], bmap->bitmap[1],
1164                         bmap->bitmap[2], bmap->bitmap[3],
1165                         bmap->bitmap[4], bmap->bitmap[5],
1166                         bmap->bitmap[6], bmap->bitmap[7]);
1167         }
1168 #endif
1169 }
1170
1171 /*
1172  * BULKFREE DEDUP HEURISTIC
1173  *
1174  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1175  *          All fields must be loaded into locals and validated.
1176  */
1177 static
1178 int
1179 h2_bulkfree_test(hammer2_bulkfree_info_t *cbinfo, hammer2_blockref_t *bref,
1180                  int pri)
1181 {
1182         hammer2_dedup_t *dedup;
1183         int best;
1184         int n;
1185         int i;
1186
1187         n = hammer2_icrc32(&bref->data_off, sizeof(bref->data_off));
1188         dedup = cbinfo->dedup + (n & (HAMMER2_DEDUP_HEUR_MASK & ~7));
1189
1190         for (i = best = 0; i < 8; ++i) {
1191                 if (dedup[i].data_off == bref->data_off) {
1192                         if (dedup[i].ticks < pri)
1193                                 dedup[i].ticks = pri;
1194                         if (pri == 1)
1195                                 cbinfo->count_dedup_factor += dedup[i].ticks;
1196                         return 1;
1197                 }
1198                 if (dedup[i].ticks < dedup[best].ticks)
1199                         best = i;
1200         }
1201         dedup[best].data_off = bref->data_off;
1202         dedup[best].ticks = pri;
1203
1204         return 0;
1205 }