hammer - Fix bugs, fix serious snapshot bug, flush adjustments
[dragonfly.git] / sys / vfs / hammer2 / hammer2_freemap.c
1 /*
2  * Copyright (c) 2011-2018 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  * 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 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/fcntl.h>
39 #include <sys/buf.h>
40 #include <sys/proc.h>
41 #include <sys/namei.h>
42 #include <sys/mount.h>
43 #include <sys/vnode.h>
44 #include <sys/mountctl.h>
45
46 #include "hammer2.h"
47
48 #define FREEMAP_DEBUG   0
49
50 struct hammer2_fiterate {
51         hammer2_off_t   bpref;
52         hammer2_off_t   bnext;
53         int             loops;
54         int             relaxed;
55 };
56
57 typedef struct hammer2_fiterate hammer2_fiterate_t;
58
59 static int hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
60                         hammer2_blockref_t *bref, int radix,
61                         hammer2_fiterate_t *iter, hammer2_tid_t mtid);
62 static void hammer2_freemap_init(hammer2_dev_t *hmp,
63                         hammer2_key_t key, hammer2_chain_t *chain);
64 static int hammer2_bmap_alloc(hammer2_dev_t *hmp,
65                         hammer2_bmap_data_t *bmap, uint16_t class,
66                         int n, int sub_key, int radix, hammer2_key_t *basep);
67 static int hammer2_freemap_iterate(hammer2_chain_t **parentp,
68                         hammer2_chain_t **chainp,
69                         hammer2_fiterate_t *iter);
70
71 static __inline
72 int
73 hammer2_freemapradix(int radix)
74 {
75         return(radix);
76 }
77
78 /*
79  * Calculate the device offset for the specified FREEMAP_NODE or FREEMAP_LEAF
80  * bref.  Return a combined media offset and physical size radix.  Freemap
81  * chains use fixed storage offsets in the 4MB reserved area at the
82  * beginning of each 2GB zone
83  *
84  * XXX I made a mistake and made the reserved area begin at each LEVEL1 zone,
85  *     which is on a 1GB demark.  This will eat a little more space but for
86  *     now we retain compatibility and make FMZONEBASE every 1GB
87  *
88  *     (see same thing in hammer2_bulkfree.c near the top, as well as in
89  *     newfs_hammer2).
90  *
91  * Rotate between four possibilities.  Theoretically this means we have three
92  * good freemaps in case of a crash which we can use as a base for the fixup
93  * scan at mount-time.
94  */
95 #define H2FMZONEBASE(key)       ((key) & ~HAMMER2_FREEMAP_LEVEL1_MASK)
96 #define H2FMBASE(key, radix)    ((key) & ~(((hammer2_off_t)1 << (radix)) - 1))
97 #define H2FMSHIFT(radix)        ((hammer2_off_t)1 << (radix))
98
99 static
100 int
101 hammer2_freemap_reserve(hammer2_chain_t *chain, int radix)
102 {
103         hammer2_blockref_t *bref = &chain->bref;
104         hammer2_off_t off;
105         int index;
106         int index_inc;
107         size_t bytes;
108
109         /*
110          * Physical allocation size.
111          */
112         bytes = (size_t)1 << radix;
113
114         /*
115          * Calculate block selection index 0..7 of current block.  If this
116          * is the first allocation of the block (verses a modification of an
117          * existing block), we use index 0, otherwise we use the next rotating
118          * index.
119          */
120         if ((bref->data_off & ~HAMMER2_OFF_MASK_RADIX) == 0) {
121                 index = 0;
122         } else {
123                 off = bref->data_off & ~HAMMER2_OFF_MASK_RADIX &
124                       (((hammer2_off_t)1 <<
125                         HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
126                 off = off / HAMMER2_PBUFSIZE;
127                 KKASSERT(off >= HAMMER2_ZONE_FREEMAP_00 &&
128                          off < HAMMER2_ZONE_FREEMAP_END);
129                 index = (int)(off - HAMMER2_ZONE_FREEMAP_00) /
130                         HAMMER2_ZONE_FREEMAP_INC;
131                 KKASSERT(index >= 0 && index < HAMMER2_NFREEMAPS);
132                 if (++index == HAMMER2_NFREEMAPS)
133                         index = 0;
134         }
135
136         /*
137          * Calculate the block offset of the reserved block.  This will
138          * point into the 4MB reserved area at the base of the appropriate
139          * 2GB zone, once added to the FREEMAP_x selection above.
140          */
141         index_inc = index * HAMMER2_ZONE_FREEMAP_INC;
142
143         switch(bref->keybits) {
144         /* case HAMMER2_FREEMAP_LEVEL6_RADIX: not applicable */
145         case HAMMER2_FREEMAP_LEVEL5_RADIX:      /* 2EB */
146                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
147                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
148                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL5_RADIX) +
149                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
150                        HAMMER2_ZONEFM_LEVEL5) * HAMMER2_PBUFSIZE;
151                 break;
152         case HAMMER2_FREEMAP_LEVEL4_RADIX:      /* 2EB */
153                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
154                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
155                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL4_RADIX) +
156                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
157                        HAMMER2_ZONEFM_LEVEL4) * HAMMER2_PBUFSIZE;
158                 break;
159         case HAMMER2_FREEMAP_LEVEL3_RADIX:      /* 2PB */
160                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
161                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
162                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL3_RADIX) +
163                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
164                        HAMMER2_ZONEFM_LEVEL3) * HAMMER2_PBUFSIZE;
165                 break;
166         case HAMMER2_FREEMAP_LEVEL2_RADIX:      /* 2TB */
167                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE);
168                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
169                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL2_RADIX) +
170                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
171                        HAMMER2_ZONEFM_LEVEL2) * HAMMER2_PBUFSIZE;
172                 break;
173         case HAMMER2_FREEMAP_LEVEL1_RADIX:      /* 2GB */
174                 KKASSERT(bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
175                 KKASSERT(bytes == HAMMER2_FREEMAP_LEVELN_PSIZE);
176                 off = H2FMBASE(bref->key, HAMMER2_FREEMAP_LEVEL1_RADIX) +
177                       (index_inc + HAMMER2_ZONE_FREEMAP_00 +
178                        HAMMER2_ZONEFM_LEVEL1) * HAMMER2_PBUFSIZE;
179                 break;
180         default:
181                 panic("freemap: bad radix(2) %p %d\n", bref, bref->keybits);
182                 /* NOT REACHED */
183                 off = (hammer2_off_t)-1;
184                 break;
185         }
186         bref->data_off = off | radix;
187 #if FREEMAP_DEBUG
188         kprintf("FREEMAP BLOCK TYPE %d %016jx/%d DATA_OFF=%016jx\n",
189                 bref->type, bref->key, bref->keybits, bref->data_off);
190 #endif
191         return (0);
192 }
193
194 /*
195  * Normal freemap allocator
196  *
197  * Use available hints to allocate space using the freemap.  Create missing
198  * freemap infrastructure on-the-fly as needed (including marking initial
199  * allocations using the iterator as allocated, instantiating new 2GB zones,
200  * and dealing with the end-of-media edge case).
201  *
202  * ip and bpref are only used as a heuristic to determine locality of
203  * reference.  bref->key may also be used heuristically.
204  *
205  * This function is a NOP if bytes is 0.
206  */
207 int
208 hammer2_freemap_alloc(hammer2_chain_t *chain, size_t bytes)
209 {
210         hammer2_dev_t *hmp = chain->hmp;
211         hammer2_blockref_t *bref = &chain->bref;
212         hammer2_chain_t *parent;
213         hammer2_tid_t mtid;
214         int radix;
215         int error;
216         unsigned int hindex;
217         hammer2_fiterate_t iter;
218
219         /*
220          * If allocating or downsizing to zero we just get rid of whatever
221          * data_off we had.
222          */
223         if (bytes == 0) {
224                 chain->bref.data_off = 0;
225                 return 0;
226         }
227
228         KKASSERT(hmp->spmp);
229         mtid = hammer2_trans_sub(hmp->spmp);
230
231         /*
232          * Validate the allocation size.  It must be a power of 2.
233          *
234          * For now require that the caller be aware of the minimum
235          * allocation (1K).
236          */
237         radix = hammer2_getradix(bytes);
238         KKASSERT((size_t)1 << radix == bytes);
239
240         if (bref->type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
241             bref->type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
242                 /*
243                  * Freemap blocks themselves are assigned from the reserve
244                  * area, not allocated from the freemap.
245                  */
246                 error = hammer2_freemap_reserve(chain, radix);
247
248                 return error;
249         }
250
251         KKASSERT(bytes >= HAMMER2_ALLOC_MIN && bytes <= HAMMER2_ALLOC_MAX);
252
253         /*
254          * Calculate the starting point for our allocation search.
255          *
256          * Each freemap leaf is dedicated to a specific freemap_radix.
257          * The freemap_radix can be more fine-grained than the device buffer
258          * radix which results in inodes being grouped together in their
259          * own segment, terminal-data (16K or less) and initial indirect
260          * block being grouped together, and then full-indirect and full-data
261          * blocks (64K) being grouped together.
262          *
263          * The single most important aspect of this is the inode grouping
264          * because that is what allows 'find' and 'ls' and other filesystem
265          * topology operations to run fast.
266          */
267 #if 0
268         if (bref->data_off & ~HAMMER2_OFF_MASK_RADIX)
269                 bpref = bref->data_off & ~HAMMER2_OFF_MASK_RADIX;
270         else if (trans->tmp_bpref)
271                 bpref = trans->tmp_bpref;
272         else if (trans->tmp_ip)
273                 bpref = trans->tmp_ip->chain->bref.data_off;
274         else
275 #endif
276         /*
277          * Heuristic tracking index.  We would like one for each distinct
278          * bref type if possible.  heur_freemap[] has room for two classes
279          * for each type.  At a minimum we have to break-up our heuristic
280          * by device block sizes.
281          */
282         hindex = hammer2_devblkradix(radix) - HAMMER2_MINIORADIX;
283         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_NRADIX);
284         hindex += bref->type * HAMMER2_FREEMAP_HEUR_NRADIX;
285         hindex &= HAMMER2_FREEMAP_HEUR_TYPES * HAMMER2_FREEMAP_HEUR_NRADIX - 1;
286         KKASSERT(hindex < HAMMER2_FREEMAP_HEUR_SIZE);
287
288         iter.bpref = hmp->heur_freemap[hindex];
289         iter.relaxed = hmp->freemap_relaxed;
290
291         /*
292          * Make sure bpref is in-bounds.  It's ok if bpref covers a zone's
293          * reserved area, the try code will iterate past it.
294          */
295         if (iter.bpref > hmp->voldata.volu_size)
296                 iter.bpref = hmp->voldata.volu_size - 1;
297
298         /*
299          * Iterate the freemap looking for free space before and after.
300          */
301         parent = &hmp->fchain;
302         hammer2_chain_ref(parent);
303         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
304         error = HAMMER2_ERROR_EAGAIN;
305         iter.bnext = iter.bpref;
306         iter.loops = 0;
307
308         while (error == HAMMER2_ERROR_EAGAIN) {
309                 error = hammer2_freemap_try_alloc(&parent, bref, radix,
310                                                   &iter, mtid);
311         }
312         hmp->freemap_relaxed |= iter.relaxed;   /* heuristical, SMP race ok */
313         hmp->heur_freemap[hindex] = iter.bnext;
314         hammer2_chain_unlock(parent);
315         hammer2_chain_drop(parent);
316
317         return (error);
318 }
319
320 static int
321 hammer2_freemap_try_alloc(hammer2_chain_t **parentp,
322                           hammer2_blockref_t *bref, int radix,
323                           hammer2_fiterate_t *iter, hammer2_tid_t mtid)
324 {
325         hammer2_dev_t *hmp = (*parentp)->hmp;
326         hammer2_off_t l0size;
327         hammer2_off_t l1size;
328         hammer2_off_t l1mask;
329         hammer2_key_t key_dummy;
330         hammer2_chain_t *chain;
331         hammer2_off_t key;
332         size_t bytes;
333         uint16_t class;
334         int error;
335
336         /*
337          * Calculate the number of bytes being allocated, the number
338          * of contiguous bits of bitmap being allocated, and the bitmap
339          * mask.
340          *
341          * WARNING! cpu hardware may mask bits == 64 -> 0 and blow up the
342          *          mask calculation.
343          */
344         bytes = (size_t)1 << radix;
345         class = (bref->type << 8) | hammer2_devblkradix(radix);
346
347         /*
348          * Lookup the level1 freemap chain, creating and initializing one
349          * if necessary.  Intermediate levels will be created automatically
350          * when necessary by hammer2_chain_create().
351          */
352         key = H2FMBASE(iter->bnext, HAMMER2_FREEMAP_LEVEL1_RADIX);
353         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
354         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
355         l1mask = l1size - 1;
356
357         chain = hammer2_chain_lookup(parentp, &key_dummy, key, key + l1mask,
358                                      &error,
359                                      HAMMER2_LOOKUP_ALWAYS |
360                                      HAMMER2_LOOKUP_MATCHIND);
361
362         if (chain == NULL) {
363                 /*
364                  * Create the missing leaf, be sure to initialize
365                  * the auxillary freemap tracking information in
366                  * the bref.check.freemap structure.
367                  */
368 #if 0
369                 kprintf("freemap create L1 @ %016jx bpref %016jx\n",
370                         key, iter->bpref);
371 #endif
372                 error = hammer2_chain_create(parentp, &chain,
373                                      hmp->spmp, HAMMER2_METH_DEFAULT,
374                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
375                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
376                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
377                                      mtid, 0, 0);
378                 KKASSERT(error == 0);
379                 if (error == 0) {
380                         hammer2_chain_modify(chain, mtid, 0, 0);
381                         bzero(&chain->data->bmdata[0],
382                               HAMMER2_FREEMAP_LEVELN_PSIZE);
383                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
384                         chain->bref.check.freemap.avail = l1size;
385                         /* bref.methods should already be inherited */
386
387                         hammer2_freemap_init(hmp, key, chain);
388                 }
389         } else if (chain->error) {
390                 /*
391                  * Error during lookup.
392                  */
393                 kprintf("hammer2_freemap_try_alloc: %016jx: error %s\n",
394                         (intmax_t)bref->data_off,
395                         hammer2_error_str(chain->error));
396                 error = HAMMER2_ERROR_EIO;
397         } else if ((chain->bref.check.freemap.bigmask &
398                    ((size_t)1 << radix)) == 0) {
399                 /*
400                  * Already flagged as not having enough space
401                  */
402                 error = HAMMER2_ERROR_ENOSPC;
403         } else {
404                 /*
405                  * Modify existing chain to setup for adjustment.
406                  */
407                 hammer2_chain_modify(chain, mtid, 0, 0);
408         }
409
410         /*
411          * Scan 4MB entries.
412          */
413         if (error == 0) {
414                 hammer2_bmap_data_t *bmap;
415                 hammer2_key_t base_key;
416                 int count;
417                 int start;
418                 int n;
419
420                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF);
421                 start = (int)((iter->bnext - key) >>
422                               HAMMER2_FREEMAP_LEVEL0_RADIX);
423                 KKASSERT(start >= 0 && start < HAMMER2_FREEMAP_COUNT);
424                 hammer2_chain_modify(chain, mtid, 0, 0);
425
426                 error = HAMMER2_ERROR_ENOSPC;
427                 for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
428                         int availchk;
429
430                         if (start + count >= HAMMER2_FREEMAP_COUNT &&
431                             start - count < 0) {
432                                 break;
433                         }
434
435                         /*
436                          * Calculate bmap pointer from thart starting index
437                          * forwards.
438                          *
439                          * NOTE: bmap pointer is invalid if n >= FREEMAP_COUNT.
440                          */
441                         n = start + count;
442                         bmap = &chain->data->bmdata[n];
443
444                         if (n >= HAMMER2_FREEMAP_COUNT) {
445                                 availchk = 0;
446                         } else if (bmap->avail) {
447                                 availchk = 1;
448                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
449                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
450                                 availchk = 1;
451                         } else {
452                                 availchk = 0;
453                         }
454
455                         /*
456                          * Try to allocate from a matching freemap class
457                          * superblock.  If we are in relaxed mode we allocate
458                          * from any freemap class superblock.
459                          */
460                         if (availchk &&
461                             (bmap->class == 0 || bmap->class == class ||
462                              iter->relaxed)) {
463                                 base_key = key + n * l0size;
464                                 error = hammer2_bmap_alloc(hmp, bmap,
465                                                            class, n,
466                                                            (int)bref->key,
467                                                            radix,
468                                                            &base_key);
469                                 if (error != HAMMER2_ERROR_ENOSPC) {
470                                         key = base_key;
471                                         break;
472                                 }
473                         }
474
475                         /*
476                          * Calculate bmap pointer from thart starting index
477                          * backwards (locality).
478                          *
479                          * Must recalculate after potentially having called
480                          * hammer2_bmap_alloc() above in case chain was
481                          * reallocated.
482                          *
483                          * NOTE: bmap pointer is invalid if n < 0.
484                          */
485                         n = start - count;
486                         bmap = &chain->data->bmdata[n];
487                         if (n < 0) {
488                                 availchk = 0;
489                         } else if (bmap->avail) {
490                                 availchk = 1;
491                         } else if (radix < HAMMER2_FREEMAP_BLOCK_RADIX &&
492                                   (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK)) {
493                                 availchk = 1;
494                         } else {
495                                 availchk = 0;
496                         }
497
498                         /*
499                          * Try to allocate from a matching freemap class
500                          * superblock.  If we are in relaxed mode we allocate
501                          * from any freemap class superblock.
502                          */
503                         if (availchk &&
504                             (bmap->class == 0 || bmap->class == class ||
505                             iter->relaxed)) {
506                                 base_key = key + n * l0size;
507                                 error = hammer2_bmap_alloc(hmp, bmap,
508                                                            class, n,
509                                                            (int)bref->key,
510                                                            radix,
511                                                            &base_key);
512                                 if (error != HAMMER2_ERROR_ENOSPC) {
513                                         key = base_key;
514                                         break;
515                                 }
516                         }
517                 }
518
519                 /*
520                  * We only know for sure that we can clear the bitmap bit
521                  * if we scanned the entire array (start == 0).
522                  */
523                 if (error == HAMMER2_ERROR_ENOSPC && start == 0) {
524                         chain->bref.check.freemap.bigmask &=
525                                 (uint32_t)~((size_t)1 << radix);
526                 }
527                 /* XXX also scan down from original count */
528         }
529
530         if (error == 0) {
531                 /*
532                  * Assert validity.  Must be beyond the static allocator used
533                  * by newfs_hammer2 (and thus also beyond the aux area),
534                  * not go past the volume size, and must not be in the
535                  * reserved segment area for a zone.
536                  */
537                 KKASSERT(key >= hmp->voldata.allocator_beg &&
538                          key + bytes <= hmp->voldata.volu_size);
539                 KKASSERT((key & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
540                 bref->data_off = key | radix;
541
542                 /*
543                  * Record dedupability.  The dedup bits are cleared
544                  * when bulkfree transitions the freemap from 11->10,
545                  * and asserted to be clear on the 10->00 transition.
546                  *
547                  * We must record the bitmask with the chain locked
548                  * at the time we set the allocation bits to avoid
549                  * racing a bulkfree.
550                  */
551                 if (bref->type == HAMMER2_BREF_TYPE_DATA)
552                         hammer2_io_dedup_set(hmp, bref);
553 #if 0
554                 kprintf("alloc cp=%p %016jx %016jx using %016jx\n",
555                         chain,
556                         bref->key, bref->data_off, chain->bref.data_off);
557 #endif
558         } else if (error == HAMMER2_ERROR_ENOSPC) {
559                 /*
560                  * Return EAGAIN with next iteration in iter->bnext, or
561                  * return ENOSPC if the allocation map has been exhausted.
562                  */
563                 error = hammer2_freemap_iterate(parentp, &chain, iter);
564         }
565
566         /*
567          * Cleanup
568          */
569         if (chain) {
570                 hammer2_chain_unlock(chain);
571                 hammer2_chain_drop(chain);
572         }
573         return (error);
574 }
575
576 /*
577  * Allocate (1<<radix) bytes from the bmap whos base data offset is (*basep).
578  *
579  * If the linear iterator is mid-block we use it directly (the bitmap should
580  * already be marked allocated), otherwise we search for a block in the
581  * bitmap that fits the allocation request.
582  *
583  * A partial bitmap allocation sets the minimum bitmap granularity (16KB)
584  * to fully allocated and adjusts the linear allocator to allow the
585  * remaining space to be allocated.
586  *
587  * sub_key is the lower 32 bits of the chain->bref.key for the chain whos
588  * bref is being allocated.  If the radix represents an allocation >= 16KB
589  * (aka HAMMER2_FREEMAP_BLOCK_RADIX) we try to use this key to select the
590  * blocks directly out of the bmap.
591  */
592 static
593 int
594 hammer2_bmap_alloc(hammer2_dev_t *hmp, hammer2_bmap_data_t *bmap,
595                    uint16_t class, int n, int sub_key,
596                    int radix, hammer2_key_t *basep)
597 {
598         size_t size;
599         size_t bgsize;
600         int bmradix;
601         hammer2_bitmap_t bmmask;
602         int offset;
603         int i;
604         int j;
605
606         /*
607          * Take into account 2-bits per block when calculating bmradix.
608          */
609         size = (size_t)1 << radix;
610
611         if (radix <= HAMMER2_FREEMAP_BLOCK_RADIX) {
612                 bmradix = 2;
613                 /* (16K) 2 bits per allocation block */
614         } else {
615                 bmradix = (hammer2_bitmap_t)2 <<
616                           (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
617                 /* (32K-256K) 4, 8, 16, 32 bits per allocation block */
618         }
619
620         /*
621          * Use the linear iterator to pack small allocations, otherwise
622          * fall-back to finding a free 16KB chunk.  The linear iterator
623          * is only valid when *NOT* on a freemap chunking boundary (16KB).
624          * If it is the bitmap must be scanned.  It can become invalid
625          * once we pack to the boundary.  We adjust it after a bitmap
626          * allocation only for sub-16KB allocations (so the perfectly good
627          * previous value can still be used for fragments when 16KB+
628          * allocations are made inbetween fragmentary allocations).
629          *
630          * Beware of hardware artifacts when bmradix == 64 (intermediate
631          * result can wind up being '1' instead of '0' if hardware masks
632          * bit-count & 63).
633          *
634          * NOTE: j needs to be even in the j= calculation.  As an artifact
635          *       of the /2 division, our bitmask has to clear bit 0.
636          *
637          * NOTE: TODO this can leave little unallocatable fragments lying
638          *       around.
639          */
640         if (((uint32_t)bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) + size <=
641             HAMMER2_FREEMAP_BLOCK_SIZE &&
642             (bmap->linear & HAMMER2_FREEMAP_BLOCK_MASK) &&
643             bmap->linear < HAMMER2_SEGSIZE) {
644                 /*
645                  * Use linear iterator if it is not block-aligned to avoid
646                  * wasting space.
647                  */
648                 KKASSERT(bmap->linear >= 0 &&
649                          bmap->linear + size <= HAMMER2_SEGSIZE &&
650                          (bmap->linear & (HAMMER2_ALLOC_MIN - 1)) == 0);
651                 offset = bmap->linear;
652                 i = offset / (HAMMER2_SEGSIZE / 8);
653                 j = (offset / (HAMMER2_FREEMAP_BLOCK_SIZE / 2)) & 30;
654                 bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
655                          HAMMER2_BMAP_ALLONES :
656                          ((hammer2_bitmap_t)1 << bmradix) - 1;
657                 bmmask <<= j;
658                 bmap->linear = offset + size;
659         } else {
660                 /*
661                  * Try to index a starting point based on sub_key.  This
662                  * attempts to restore sequential block ordering on-disk
663                  * whenever possible, even if data is committed out of
664                  * order.
665                  *
666                  * i - Index bitmapq[], full data range represented is
667                  *     HAMMER2_BMAP_SIZE.
668                  *
669                  * j - Index within bitmapq[i], full data range represented is
670                  *     HAMMER2_BMAP_INDEX_SIZE.
671                  *
672                  * WARNING!
673                  */
674                 i = -1;
675                 j = -1;
676
677                 switch(class >> 8) {
678                 case HAMMER2_BREF_TYPE_DATA:
679                         if (radix >= HAMMER2_FREEMAP_BLOCK_RADIX) {
680                                 i = (sub_key & HAMMER2_BMAP_MASK) /
681                                     (HAMMER2_BMAP_SIZE / HAMMER2_BMAP_ELEMENTS);
682                                 j = (sub_key & HAMMER2_BMAP_INDEX_MASK) /
683                                     (HAMMER2_BMAP_INDEX_SIZE /
684                                      HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
685                                 j = j * 2;
686                         }
687                         break;
688                 case HAMMER2_BREF_TYPE_INODE:
689                         break;
690                 default:
691                         break;
692                 }
693                 if (i >= 0) {
694                         KKASSERT(i < HAMMER2_BMAP_ELEMENTS &&
695                                  j < 2 * HAMMER2_BMAP_BLOCKS_PER_ELEMENT);
696                         KKASSERT(j + bmradix <= HAMMER2_BMAP_BITS_PER_ELEMENT);
697                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
698                                  HAMMER2_BMAP_ALLONES :
699                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
700                         bmmask <<= j;
701
702                         if ((bmap->bitmapq[i] & bmmask) == 0)
703                                 goto success;
704                 }
705
706                 /*
707                  * General element scan.
708                  *
709                  * WARNING: (j) is iterating a bit index (by 2's)
710                  */
711                 for (i = 0; i < HAMMER2_BMAP_ELEMENTS; ++i) {
712                         bmmask = (bmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
713                                  HAMMER2_BMAP_ALLONES :
714                                  ((hammer2_bitmap_t)1 << bmradix) - 1;
715                         for (j = 0;
716                              j < HAMMER2_BMAP_BITS_PER_ELEMENT;
717                              j += bmradix) {
718                                 if ((bmap->bitmapq[i] & bmmask) == 0)
719                                         goto success;
720                                 bmmask <<= bmradix;
721                         }
722                 }
723                 /*fragments might remain*/
724                 /*KKASSERT(bmap->avail == 0);*/
725                 return (HAMMER2_ERROR_ENOSPC);
726 success:
727                 offset = i * (HAMMER2_SEGSIZE / HAMMER2_BMAP_ELEMENTS) +
728                          (j * (HAMMER2_FREEMAP_BLOCK_SIZE / 2));
729                 if (size & HAMMER2_FREEMAP_BLOCK_MASK)
730                         bmap->linear = offset + size;
731         }
732
733         /* 8 x (64/2) -> 256 x 16K -> 4MB */
734         KKASSERT(i >= 0 && i < HAMMER2_BMAP_ELEMENTS);
735
736         /*
737          * Optimize the buffer cache to avoid unnecessary read-before-write
738          * operations.
739          *
740          * The device block size could be larger than the allocation size
741          * so the actual bitmap test is somewhat more involved.  We have
742          * to use a compatible buffer size for this operation.
743          */
744         if ((bmap->bitmapq[i] & bmmask) == 0 &&
745             hammer2_devblksize(size) != size) {
746                 size_t psize = hammer2_devblksize(size);
747                 hammer2_off_t pmask = (hammer2_off_t)psize - 1;
748                 int pbmradix = (hammer2_bitmap_t)2 <<
749                                         (hammer2_devblkradix(radix) -
750                                HAMMER2_FREEMAP_BLOCK_RADIX);
751                 hammer2_bitmap_t pbmmask;
752                 int pradix = hammer2_getradix(psize);
753
754                 pbmmask = (pbmradix == HAMMER2_BMAP_BITS_PER_ELEMENT) ?
755                         HAMMER2_BMAP_ALLONES :
756                         ((hammer2_bitmap_t)1 << pbmradix) - 1;
757                 while ((pbmmask & bmmask) == 0)
758                         pbmmask <<= pbmradix;
759
760 #if 0
761                 kprintf("%016jx mask %016jx %016jx %016jx (%zd/%zd)\n",
762                         *basep + offset, bmap->bitmapq[i],
763                         pbmmask, bmmask, size, psize);
764 #endif
765
766                 if ((bmap->bitmapq[i] & pbmmask) == 0) {
767                         hammer2_io_t *dio;
768
769                         hammer2_io_newnz(hmp, class >> 8,
770                                         (*basep + (offset & ~pmask)) |
771                                         pradix, psize, &dio);
772                         hammer2_io_putblk(&dio);
773                 }
774         }
775
776 #if 0
777         /*
778          * When initializing a new inode segment also attempt to initialize
779          * an adjacent segment.  Be careful not to index beyond the array
780          * bounds.
781          *
782          * We do this to try to localize inode accesses to improve
783          * directory scan rates.  XXX doesn't improve scan rates.
784          */
785         if (size == HAMMER2_INODE_BYTES) {
786                 if (n & 1) {
787                         if (bmap[-1].radix == 0 && bmap[-1].avail)
788                                 bmap[-1].radix = radix;
789                 } else {
790                         if (bmap[1].radix == 0 && bmap[1].avail)
791                                 bmap[1].radix = radix;
792                 }
793         }
794 #endif
795         /*
796          * Calculate the bitmap-granular change in bgsize for the volume
797          * header.  We cannot use the fine-grained change here because
798          * the bulkfree code can't undo it.  If the bitmap element is already
799          * marked allocated it has already been accounted for.
800          */
801         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
802                 if (bmap->bitmapq[i] & bmmask)
803                         bgsize = 0;
804                 else
805                         bgsize = HAMMER2_FREEMAP_BLOCK_SIZE;
806         } else {
807                 bgsize = size;
808         }
809
810         /*
811          * Adjust the bitmap, set the class (it might have been 0),
812          * and available bytes, update the allocation offset (*basep)
813          * from the L0 base to the actual offset.
814          *
815          * Do not override the class if doing a relaxed class allocation.
816          *
817          * avail must reflect the bitmap-granular availability.  The allocator
818          * tests will also check the linear iterator.
819          */
820         bmap->bitmapq[i] |= bmmask;
821         if (bmap->class == 0)
822                 bmap->class = class;
823         bmap->avail -= bgsize;
824         *basep += offset;
825
826         /*
827          * Adjust the volume header's allocator_free parameter.  This
828          * parameter has to be fixed up by bulkfree which has no way to
829          * figure out sub-16K chunking, so it must be adjusted by the
830          * bitmap-granular size.
831          */
832         if (bgsize) {
833                 hammer2_voldata_lock(hmp);
834                 hammer2_voldata_modify(hmp);
835                 hmp->voldata.allocator_free -= bgsize;
836                 hammer2_voldata_unlock(hmp);
837         }
838
839         return(0);
840 }
841
842 /*
843  * Initialize a freemap for the storage area (in bytes) that begins at (key).
844  */
845 static
846 void
847 hammer2_freemap_init(hammer2_dev_t *hmp, hammer2_key_t key,
848                      hammer2_chain_t *chain)
849 {
850         hammer2_off_t l1size;
851         hammer2_off_t lokey;
852         hammer2_off_t hikey;
853         hammer2_bmap_data_t *bmap;
854         int count;
855
856         /*
857          * LEVEL1 is 1GB, there are two level1 1GB freemaps per 2GB zone.
858          */
859         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
860
861         /*
862          * Calculate the portion of the 1GB map that should be initialized
863          * as free.  Portions below or after will be initialized as allocated.
864          * SEGMASK-align the areas so we don't have to worry about sub-scans
865          * or endianess when using memset.
866          *
867          * WARNING! It is possible for lokey to be larger than hikey if the
868          *          entire 2GB segment is within the static allocation.
869          */
870         /*
871          * (1) Ensure that all statically allocated space from newfs_hammer2
872          *     is marked allocated, and take it up to the level1 base for
873          *     this key.
874          */
875         lokey = (hmp->voldata.allocator_beg + HAMMER2_SEGMASK64) &
876                 ~HAMMER2_SEGMASK64;
877         if (lokey < H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX))
878                 lokey = H2FMBASE(key, HAMMER2_FREEMAP_LEVEL1_RADIX);
879
880         /*
881          * (2) Ensure that the reserved area is marked allocated (typically
882          *     the first 4MB of each 2GB area being represented).  Since
883          *     each LEAF represents 1GB of storage and the zone is 2GB, we
884          *     have to adjust lowkey upward every other LEAF sequentially.
885          */
886         if (lokey < H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64)
887                 lokey = H2FMZONEBASE(key) + HAMMER2_ZONE_SEG64;
888
889         /*
890          * (3) Ensure that any trailing space at the end-of-volume is marked
891          *     allocated.
892          */
893         hikey = key + H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
894         if (hikey > hmp->voldata.volu_size) {
895                 hikey = hmp->voldata.volu_size & ~HAMMER2_SEGMASK64;
896         }
897
898         /*
899          * Heuristic highest possible value
900          */
901         chain->bref.check.freemap.avail =
902                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
903         bmap = &chain->data->bmdata[0];
904
905         /*
906          * Initialize bitmap (bzero'd by caller)
907          */
908         for (count = 0; count < HAMMER2_FREEMAP_COUNT; ++count) {
909                 if (key < lokey || key >= hikey) {
910                         memset(bmap->bitmapq, -1,
911                                sizeof(bmap->bitmapq));
912                         bmap->avail = 0;
913                         bmap->linear = HAMMER2_SEGSIZE;
914                         chain->bref.check.freemap.avail -=
915                                 H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
916                 } else {
917                         bmap->avail = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
918                 }
919                 key += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
920                 ++bmap;
921         }
922 }
923
924 /*
925  * The current Level 1 freemap has been exhausted, iterate to the next
926  * one, return ENOSPC if no freemaps remain.
927  *
928  * At least two loops are required.  If we are not in relaxed mode and
929  * we run out of storage we enter relaxed mode and do a third loop.
930  * The relaxed mode is recorded back in the hmp so once we enter the mode
931  * we remain relaxed until stuff begins to get freed and only do 2 loops.
932  *
933  * XXX this should rotate back to the beginning to handle freed-up space
934  * XXX or use intermediate entries to locate free space. TODO
935  */
936 static int
937 hammer2_freemap_iterate(hammer2_chain_t **parentp, hammer2_chain_t **chainp,
938                         hammer2_fiterate_t *iter)
939 {
940         hammer2_dev_t *hmp = (*parentp)->hmp;
941
942         iter->bnext &= ~(H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX) - 1);
943         iter->bnext += H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
944         if (iter->bnext >= hmp->voldata.volu_size) {
945                 iter->bnext = 0;
946                 if (++iter->loops >= 2) {
947                         if (iter->relaxed == 0)
948                                 iter->relaxed = 1;
949                         else
950                                 return (HAMMER2_ERROR_ENOSPC);
951                 }
952         }
953         return(HAMMER2_ERROR_EAGAIN);
954 }
955
956 /*
957  * Adjust the bit-pattern for data in the freemap bitmap according to
958  * (how).  This code is called from on-mount recovery to fixup (mark
959  * as allocated) blocks whos freemap upates might not have been committed
960  * in the last crash and is used by the bulk freemap scan to stage frees.
961  *
962  * WARNING! Cannot be called with a empty-data bref (radix == 0).
963  *
964  * XXX currently disabled when how == 0 (the normal real-time case).  At
965  * the moment we depend on the bulk freescan to actually free blocks.  It
966  * will still call this routine with a non-zero how to stage possible frees
967  * and to do the actual free.
968  */
969 void
970 hammer2_freemap_adjust(hammer2_dev_t *hmp, hammer2_blockref_t *bref,
971                        int how)
972 {
973         hammer2_off_t data_off = bref->data_off;
974         hammer2_chain_t *chain;
975         hammer2_chain_t *parent;
976         hammer2_bmap_data_t *bmap;
977         hammer2_key_t key;
978         hammer2_key_t key_dummy;
979         hammer2_off_t l0size;
980         hammer2_off_t l1size;
981         hammer2_off_t l1mask;
982         hammer2_tid_t mtid;
983         hammer2_bitmap_t *bitmap;
984         const hammer2_bitmap_t bmmask00 = 0;
985         hammer2_bitmap_t bmmask01;
986         hammer2_bitmap_t bmmask10;
987         hammer2_bitmap_t bmmask11;
988         size_t bytes;
989         uint16_t class;
990         int radix;
991         int start;
992         int count;
993         int modified = 0;
994         int error;
995         size_t bgsize = 0;
996
997         KKASSERT(how == HAMMER2_FREEMAP_DORECOVER);
998
999         KKASSERT(hmp->spmp);
1000         mtid = hammer2_trans_sub(hmp->spmp);
1001
1002         radix = (int)data_off & HAMMER2_OFF_MASK_RADIX;
1003         KKASSERT(radix != 0);
1004         data_off &= ~HAMMER2_OFF_MASK_RADIX;
1005         KKASSERT(radix <= HAMMER2_RADIX_MAX);
1006
1007         if (radix)
1008                 bytes = (size_t)1 << radix;
1009         else
1010                 bytes = 0;
1011         class = (bref->type << 8) | hammer2_devblkradix(radix);
1012
1013         /*
1014          * We can't adjust the freemap for data allocations made by
1015          * newfs_hammer2.
1016          */
1017         if (data_off < hmp->voldata.allocator_beg)
1018                 return;
1019
1020         KKASSERT((data_off & HAMMER2_ZONE_MASK64) >= HAMMER2_ZONE_SEG);
1021
1022         /*
1023          * Lookup the level1 freemap chain.  The chain must exist.
1024          */
1025         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL1_RADIX);
1026         l0size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL0_RADIX);
1027         l1size = H2FMSHIFT(HAMMER2_FREEMAP_LEVEL1_RADIX);
1028         l1mask = l1size - 1;
1029
1030         parent = &hmp->fchain;
1031         hammer2_chain_ref(parent);
1032         hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1033
1034         chain = hammer2_chain_lookup(&parent, &key_dummy, key, key + l1mask,
1035                                      &error,
1036                                      HAMMER2_LOOKUP_ALWAYS |
1037                                      HAMMER2_LOOKUP_MATCHIND);
1038
1039         /*
1040          * Stop early if we are trying to free something but no leaf exists.
1041          */
1042         if (chain == NULL && how != HAMMER2_FREEMAP_DORECOVER) {
1043                 kprintf("hammer2_freemap_adjust: %016jx: no chain\n",
1044                         (intmax_t)bref->data_off);
1045                 goto done;
1046         }
1047         if (chain->error) {
1048                 kprintf("hammer2_freemap_adjust: %016jx: error %s\n",
1049                         (intmax_t)bref->data_off,
1050                         hammer2_error_str(chain->error));
1051                 hammer2_chain_unlock(chain);
1052                 hammer2_chain_drop(chain);
1053                 chain = NULL;
1054                 goto done;
1055         }
1056
1057         /*
1058          * Create any missing leaf(s) if we are doing a recovery (marking
1059          * the block(s) as being allocated instead of being freed).  Be sure
1060          * to initialize the auxillary freemap tracking info in the
1061          * bref.check.freemap structure.
1062          */
1063         if (chain == NULL && how == HAMMER2_FREEMAP_DORECOVER) {
1064                 error = hammer2_chain_create(&parent, &chain,
1065                                      hmp->spmp, HAMMER2_METH_DEFAULT,
1066                                      key, HAMMER2_FREEMAP_LEVEL1_RADIX,
1067                                      HAMMER2_BREF_TYPE_FREEMAP_LEAF,
1068                                      HAMMER2_FREEMAP_LEVELN_PSIZE,
1069                                      mtid, 0, 0);
1070
1071                 if (hammer2_debug & 0x0040) {
1072                         kprintf("fixup create chain %p %016jx:%d\n",
1073                                 chain, chain->bref.key, chain->bref.keybits);
1074                 }
1075
1076                 if (error == 0) {
1077                         error = hammer2_chain_modify(chain, mtid, 0, 0);
1078                         KKASSERT(error == 0);
1079                         bzero(&chain->data->bmdata[0],
1080                               HAMMER2_FREEMAP_LEVELN_PSIZE);
1081                         chain->bref.check.freemap.bigmask = (uint32_t)-1;
1082                         chain->bref.check.freemap.avail = l1size;
1083                         /* bref.methods should already be inherited */
1084
1085                         hammer2_freemap_init(hmp, key, chain);
1086                 }
1087                 /* XXX handle error */
1088         }
1089
1090 #if FREEMAP_DEBUG
1091         kprintf("FREEMAP ADJUST TYPE %d %016jx/%d DATA_OFF=%016jx\n",
1092                 chain->bref.type, chain->bref.key,
1093                 chain->bref.keybits, chain->bref.data_off);
1094 #endif
1095
1096         /*
1097          * Calculate the bitmask (runs in 2-bit pairs).
1098          */
1099         start = ((int)(data_off >> HAMMER2_FREEMAP_BLOCK_RADIX) & 15) * 2;
1100         bmmask01 = (hammer2_bitmap_t)1 << start;
1101         bmmask10 = (hammer2_bitmap_t)2 << start;
1102         bmmask11 = (hammer2_bitmap_t)3 << start;
1103
1104         /*
1105          * Fixup the bitmap.  Partial blocks cannot be fully freed unless
1106          * a bulk scan is able to roll them up.
1107          */
1108         if (radix < HAMMER2_FREEMAP_BLOCK_RADIX) {
1109                 count = 1;
1110                 if (how == HAMMER2_FREEMAP_DOREALFREE)
1111                         how = HAMMER2_FREEMAP_DOMAYFREE;
1112         } else {
1113                 count = 1 << (radix - HAMMER2_FREEMAP_BLOCK_RADIX);
1114         }
1115
1116         /*
1117          * [re]load the bmap and bitmap pointers.  Each bmap entry covers
1118          * a 4MB swath.  The bmap itself (LEVEL1) covers 2GB.
1119          *
1120          * Be sure to reset the linear iterator to ensure that the adjustment
1121          * is not ignored.
1122          */
1123 again:
1124         bmap = &chain->data->bmdata[(int)(data_off >> HAMMER2_SEGRADIX) &
1125                                     (HAMMER2_FREEMAP_COUNT - 1)];
1126         bitmap = &bmap->bitmapq[(int)(data_off >> (HAMMER2_SEGRADIX - 3)) & 7];
1127
1128         if (modified)
1129                 bmap->linear = 0;
1130
1131         while (count) {
1132                 KKASSERT(bmmask11);
1133                 if (how == HAMMER2_FREEMAP_DORECOVER) {
1134                         /*
1135                          * Recovery request, mark as allocated.
1136                          */
1137                         if ((*bitmap & bmmask11) != bmmask11) {
1138                                 if (modified == 0) {
1139                                         hammer2_chain_modify(chain, mtid, 0, 0);
1140                                         modified = 1;
1141                                         goto again;
1142                                 }
1143                                 if ((*bitmap & bmmask11) == bmmask00) {
1144                                         bmap->avail -=
1145                                                 HAMMER2_FREEMAP_BLOCK_SIZE;
1146                                         bgsize += HAMMER2_FREEMAP_BLOCK_SIZE;
1147                                 }
1148                                 if (bmap->class == 0)
1149                                         bmap->class = class;
1150                                 *bitmap |= bmmask11;
1151                                 if (hammer2_debug & 0x0040) {
1152                                         kprintf("hammer2_freemap_recover: "
1153                                                 "fixup type=%02x "
1154                                                 "block=%016jx/%zd\n",
1155                                                 bref->type, data_off, bytes);
1156                                 }
1157                         } else {
1158                                 /*
1159                                 kprintf("hammer2_freemap_recover:  good "
1160                                         "type=%02x block=%016jx/%zd\n",
1161                                         bref->type, data_off, bytes);
1162                                 */
1163                         }
1164                 }
1165 #if 0
1166                 /*
1167                  * XXX this stuff doesn't work, avail is miscalculated and
1168                  * code 10 means something else now.
1169                  */
1170                 else if ((*bitmap & bmmask11) == bmmask11) {
1171                         /*
1172                          * Mayfree/Realfree request and bitmap is currently
1173                          * marked as being fully allocated.
1174                          */
1175                         if (!modified) {
1176                                 hammer2_chain_modify(chain, 0);
1177                                 modified = 1;
1178                                 goto again;
1179                         }
1180                         if (how == HAMMER2_FREEMAP_DOREALFREE)
1181                                 *bitmap &= ~bmmask11;
1182                         else
1183                                 *bitmap = (*bitmap & ~bmmask11) | bmmask10;
1184                 } else if ((*bitmap & bmmask11) == bmmask10) {
1185                         /*
1186                          * Mayfree/Realfree request and bitmap is currently
1187                          * marked as being possibly freeable.
1188                          */
1189                         if (how == HAMMER2_FREEMAP_DOREALFREE) {
1190                                 if (!modified) {
1191                                         hammer2_chain_modify(chain, 0);
1192                                         modified = 1;
1193                                         goto again;
1194                                 }
1195                                 *bitmap &= ~bmmask11;
1196                         }
1197                 } else {
1198                         /*
1199                          * 01 - Not implemented, currently illegal state
1200                          * 00 - Not allocated at all, illegal free.
1201                          */
1202                         panic("hammer2_freemap_adjust: "
1203                               "Illegal state %08x(%08x)",
1204                               *bitmap, *bitmap & bmmask11);
1205                 }
1206 #endif
1207                 --count;
1208                 bmmask01 <<= 2;
1209                 bmmask10 <<= 2;
1210                 bmmask11 <<= 2;
1211         }
1212 #if HAMMER2_BMAP_ELEMENTS != 8
1213 #error "hammer2_freemap.c: HAMMER2_BMAP_ELEMENTS expected to be 8"
1214 #endif
1215         if (how == HAMMER2_FREEMAP_DOREALFREE && modified) {
1216                 bmap->avail += 1 << radix;
1217                 KKASSERT(bmap->avail <= HAMMER2_SEGSIZE);
1218                 if (bmap->avail == HAMMER2_SEGSIZE &&
1219                     bmap->bitmapq[0] == 0 &&
1220                     bmap->bitmapq[1] == 0 &&
1221                     bmap->bitmapq[2] == 0 &&
1222                     bmap->bitmapq[3] == 0 &&
1223                     bmap->bitmapq[4] == 0 &&
1224                     bmap->bitmapq[5] == 0 &&
1225                     bmap->bitmapq[6] == 0 &&
1226                     bmap->bitmapq[7] == 0) {
1227                         key = H2FMBASE(data_off, HAMMER2_FREEMAP_LEVEL0_RADIX);
1228                         kprintf("Freeseg %016jx\n", (intmax_t)key);
1229                         bmap->class = 0;
1230                 }
1231         }
1232
1233         /*
1234          * chain->bref.check.freemap.bigmask (XXX)
1235          *
1236          * Setting bigmask is a hint to the allocation code that there might
1237          * be something allocatable.  We also set this in recovery... it
1238          * doesn't hurt and we might want to use the hint for other validation
1239          * operations later on.
1240          *
1241          * We could calculate the largest possible allocation and set the
1242          * radii that could fit, but its easier just to set bigmask to -1.
1243          */
1244         if (modified) {
1245                 chain->bref.check.freemap.bigmask = -1;
1246                 hmp->freemap_relaxed = 0;       /* reset heuristic */
1247         }
1248
1249         hammer2_chain_unlock(chain);
1250         hammer2_chain_drop(chain);
1251 done:
1252         hammer2_chain_unlock(parent);
1253         hammer2_chain_drop(parent);
1254
1255         if (bgsize) {
1256                 hammer2_voldata_lock(hmp);
1257                 hammer2_voldata_modify(hmp);
1258                 hmp->voldata.allocator_free -= bgsize;
1259                 hammer2_voldata_unlock(hmp);
1260         }
1261 }
1262
1263 /*
1264  * Validate the freemap, in three stages.
1265  *
1266  * stage-1      ALLOCATED     -> POSSIBLY FREE
1267  *              POSSIBLY FREE -> POSSIBLY FREE (type corrected)
1268  *
1269  *      This transitions bitmap entries from ALLOCATED to POSSIBLY FREE.
1270  *      The POSSIBLY FREE state does not mean that a block is actually free
1271  *      and may be transitioned back to ALLOCATED in stage-2.
1272  *
1273  *      This is typically done during normal filesystem operations when
1274  *      something is deleted or a block is replaced.
1275  *
1276  *      This is done by bulkfree in-bulk after a memory-bounded meta-data
1277  *      scan to try to determine what might be freeable.
1278  *
1279  *      This can be done unconditionally through a freemap scan when the
1280  *      intention is to brute-force recover the proper state of the freemap.
1281  *
1282  * stage-2      POSSIBLY FREE -> ALLOCATED      (scan metadata topology)
1283  *
1284  *      This is done by bulkfree during a meta-data scan to ensure that
1285  *      all blocks still actually allocated by the filesystem are marked
1286  *      as such.
1287  *
1288  *      NOTE! Live filesystem transitions to POSSIBLY FREE can occur while
1289  *            the bulkfree stage-2 and stage-3 is running.  The live filesystem
1290  *            will use the alternative POSSIBLY FREE type (2) to prevent
1291  *            stage-3 from improperly transitioning unvetted possibly-free
1292  *            blocks to FREE.
1293  *
1294  * stage-3      POSSIBLY FREE (type 1) -> FREE  (scan freemap)
1295  *
1296  *      This is done by bulkfree to finalize POSSIBLY FREE states.
1297  *
1298  */