hammer2 - update documentation, begin working on callback I/O
[dragonfly.git] / sys / vfs / hammer2 / hammer2_chain.c
1 /*
2  * Copyright (c) 2011-2014 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  * and Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 /*
36  * This subsystem implements most of the core support functions for
37  * the hammer2_chain structure.
38  *
39  * Chains are the in-memory version on media objects (volume header, inodes,
40  * indirect blocks, data blocks, etc).  Chains represent a portion of the
41  * HAMMER2 topology.
42  *
43  * Chains are no-longer delete-duplicated.  Instead, the original in-memory
44  * chain will be moved along with its block reference (e.g. for things like
45  * renames, hardlink operations, modifications, etc), and will be indexed
46  * on a secondary list for flush handling instead of propagating a flag
47  * upward to the root.
48  *
49  * Concurrent front-end operations can still run against backend flushes
50  * as long as they do not cross the current flush boundary.  An operation
51  * running above the current flush (in areas not yet flushed) can become
52  * part of the current flush while ano peration running below the current
53  * flush can become part of the next flush.
54  */
55 #include <sys/cdefs.h>
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/types.h>
59 #include <sys/lock.h>
60 #include <sys/kern_syscall.h>
61 #include <sys/uuid.h>
62
63 #include <crypto/sha2/sha2.h>
64
65 #include "hammer2.h"
66
67 static int hammer2_indirect_optimize;   /* XXX SYSCTL */
68
69 static hammer2_chain_t *hammer2_chain_create_indirect(
70                 hammer2_trans_t *trans, hammer2_chain_t *parent,
71                 hammer2_key_t key, int keybits, int for_type, int *errorp);
72 static void hammer2_chain_drop_data(hammer2_chain_t *chain, int lastdrop);
73 static hammer2_chain_t *hammer2_combined_find(
74                 hammer2_chain_t *parent,
75                 hammer2_blockref_t *base, int count,
76                 int *cache_indexp, hammer2_key_t *key_nextp,
77                 hammer2_key_t key_beg, hammer2_key_t key_end,
78                 hammer2_blockref_t **bresp);
79
80 /*
81  * Basic RBTree for chains (core->rbtree and core->dbtree).  Chains cannot
82  * overlap in the RB trees.  Deleted chains are moved from rbtree to either
83  * dbtree or to dbq.
84  *
85  * Chains in delete-duplicate sequences can always iterate through core_entry
86  * to locate the live version of the chain.
87  */
88 RB_GENERATE(hammer2_chain_tree, hammer2_chain, rbnode, hammer2_chain_cmp);
89
90 int
91 hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2)
92 {
93         hammer2_key_t c1_beg;
94         hammer2_key_t c1_end;
95         hammer2_key_t c2_beg;
96         hammer2_key_t c2_end;
97
98         /*
99          * Compare chains.  Overlaps are not supposed to happen and catch
100          * any software issues early we count overlaps as a match.
101          */
102         c1_beg = chain1->bref.key;
103         c1_end = c1_beg + ((hammer2_key_t)1 << chain1->bref.keybits) - 1;
104         c2_beg = chain2->bref.key;
105         c2_end = c2_beg + ((hammer2_key_t)1 << chain2->bref.keybits) - 1;
106
107         if (c1_end < c2_beg)    /* fully to the left */
108                 return(-1);
109         if (c1_beg > c2_end)    /* fully to the right */
110                 return(1);
111         return(0);              /* overlap (must not cross edge boundary) */
112 }
113
114 static __inline
115 int
116 hammer2_isclusterable(hammer2_chain_t *chain)
117 {
118         if (hammer2_cluster_enable) {
119                 if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
120                     chain->bref.type == HAMMER2_BREF_TYPE_INODE ||
121                     chain->bref.type == HAMMER2_BREF_TYPE_DATA) {
122                         return(1);
123                 }
124         }
125         return(0);
126 }
127
128 /*
129  * Make a chain visible to the flusher.  The flusher needs to be able to
130  * do flushes of a subdirectory chains or single files so it does a top-down
131  * recursion using the ONFLUSH flag for the recursion.  It locates MODIFIED
132  * or UPDATE chains and flushes back up the chain to the root.
133  */
134 void
135 hammer2_chain_setflush(hammer2_trans_t *trans, hammer2_chain_t *chain)
136 {
137         hammer2_chain_t *parent;
138
139         if ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
140                 spin_lock(&chain->core.cst.spin);
141                 while ((chain->flags & HAMMER2_CHAIN_ONFLUSH) == 0) {
142                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONFLUSH);
143                         if ((parent = chain->parent) == NULL)
144                                 break;
145                         spin_lock(&parent->core.cst.spin);
146                         spin_unlock(&chain->core.cst.spin);
147                         chain = parent;
148                 }
149                 spin_unlock(&chain->core.cst.spin);
150         }
151 }
152
153 /*
154  * Allocate a new disconnected chain element representing the specified
155  * bref.  chain->refs is set to 1 and the passed bref is copied to
156  * chain->bref.  chain->bytes is derived from the bref.
157  *
158  * chain->core is NOT allocated and the media data and bp pointers are left
159  * NULL.  The caller must call chain_core_alloc() to allocate or associate
160  * a core with the chain.
161  *
162  * chain->pmp inherits pmp unless the chain is an inode (other than the
163  * super-root inode).
164  *
165  * NOTE: Returns a referenced but unlocked (because there is no core) chain.
166  */
167 hammer2_chain_t *
168 hammer2_chain_alloc(hammer2_mount_t *hmp, hammer2_pfsmount_t *pmp,
169                     hammer2_trans_t *trans, hammer2_blockref_t *bref)
170 {
171         hammer2_chain_t *chain;
172         u_int bytes = 1U << (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
173
174         /*
175          * Construct the appropriate system structure.
176          */
177         switch(bref->type) {
178         case HAMMER2_BREF_TYPE_INODE:
179         case HAMMER2_BREF_TYPE_INDIRECT:
180         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
181         case HAMMER2_BREF_TYPE_DATA:
182         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
183                 /*
184                  * Chain's are really only associated with the hmp but we
185                  * maintain a pmp association for per-mount memory tracking
186                  * purposes.  The pmp can be NULL.
187                  */
188                 chain = kmalloc(sizeof(*chain), hmp->mchain, M_WAITOK | M_ZERO);
189                 break;
190         case HAMMER2_BREF_TYPE_VOLUME:
191         case HAMMER2_BREF_TYPE_FREEMAP:
192                 chain = NULL;
193                 panic("hammer2_chain_alloc volume type illegal for op");
194         default:
195                 chain = NULL;
196                 panic("hammer2_chain_alloc: unrecognized blockref type: %d",
197                       bref->type);
198         }
199
200         /*
201          * Initialize the new chain structure.
202          */
203         chain->pmp = pmp;
204         chain->hmp = hmp;
205         chain->bref = *bref;
206         chain->bytes = bytes;
207         chain->refs = 1;
208         chain->flags = HAMMER2_CHAIN_ALLOCATED;
209
210         /*
211          * Set the PFS boundary flag if this chain represents a PFS root.
212          */
213         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
214                 chain->flags |= HAMMER2_CHAIN_PFSBOUNDARY;
215
216         return (chain);
217 }
218
219 /*
220  * Associate an existing core with the chain or allocate a new core.
221  *
222  * The core is not locked.  No additional refs on the chain are made.
223  * (trans) must not be NULL if (core) is not NULL.
224  *
225  * When chains are delete-duplicated during flushes we insert nchain on
226  * the ownerq after ochain instead of at the end in order to give the
227  * drop code visibility in the correct order, otherwise drops can be missed.
228  */
229 void
230 hammer2_chain_core_alloc(hammer2_trans_t *trans, hammer2_chain_t *chain)
231 {
232         hammer2_chain_core_t *core = &chain->core;
233
234         /*
235          * Fresh core under nchain (no multi-homing of ochain's
236          * sub-tree).
237          */
238         RB_INIT(&core->rbtree); /* live chains */
239         ccms_cst_init(&core->cst, chain);
240 }
241
242 /*
243  * Add a reference to a chain element, preventing its destruction.
244  *
245  * (can be called with spinlock held)
246  */
247 void
248 hammer2_chain_ref(hammer2_chain_t *chain)
249 {
250         atomic_add_int(&chain->refs, 1);
251 }
252
253 /*
254  * Insert the chain in the core rbtree.
255  *
256  * Normal insertions are placed in the live rbtree.  Insertion of a deleted
257  * chain is a special case used by the flush code that is placed on the
258  * unstaged deleted list to avoid confusing the live view.
259  */
260 #define HAMMER2_CHAIN_INSERT_SPIN       0x0001
261 #define HAMMER2_CHAIN_INSERT_LIVE       0x0002
262 #define HAMMER2_CHAIN_INSERT_RACE       0x0004
263
264 static
265 int
266 hammer2_chain_insert(hammer2_chain_t *parent, hammer2_chain_t *chain,
267                      int flags, int generation)
268 {
269         hammer2_chain_t *xchain;
270         int error = 0;
271
272         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
273                 spin_lock(&parent->core.cst.spin);
274
275         /*
276          * Interlocked by spinlock, check for race
277          */
278         if ((flags & HAMMER2_CHAIN_INSERT_RACE) &&
279             parent->core.generation != generation) {
280                 error = EAGAIN;
281                 goto failed;
282         }
283
284         /*
285          * Insert chain
286          */
287         xchain = RB_INSERT(hammer2_chain_tree, &parent->core.rbtree, chain);
288         KASSERT(xchain == NULL,
289                 ("hammer2_chain_insert: collision %p %p", chain, xchain));
290         atomic_set_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
291         chain->parent = parent;
292         ++parent->core.chain_count;
293         ++parent->core.generation;      /* XXX incs for _get() too, XXX */
294
295         /*
296          * We have to keep track of the effective live-view blockref count
297          * so the create code knows when to push an indirect block.
298          */
299         if (flags & HAMMER2_CHAIN_INSERT_LIVE)
300                 atomic_add_int(&parent->core.live_count, 1);
301 failed:
302         if (flags & HAMMER2_CHAIN_INSERT_SPIN)
303                 spin_unlock(&parent->core.cst.spin);
304         return error;
305 }
306
307 /*
308  * Drop the caller's reference to the chain.  When the ref count drops to
309  * zero this function will try to disassociate the chain from its parent and
310  * deallocate it, then recursely drop the parent using the implied ref
311  * from the chain's chain->parent.
312  */
313 static hammer2_chain_t *hammer2_chain_lastdrop(hammer2_chain_t *chain);
314
315 void
316 hammer2_chain_drop(hammer2_chain_t *chain)
317 {
318         u_int refs;
319         u_int need = 0;
320
321         if (hammer2_debug & 0x200000)
322                 Debugger("drop");
323
324         if (chain->flags & HAMMER2_CHAIN_UPDATE)
325                 ++need;
326         if (chain->flags & HAMMER2_CHAIN_MODIFIED)
327                 ++need;
328         KKASSERT(chain->refs > need);
329
330         while (chain) {
331                 refs = chain->refs;
332                 cpu_ccfence();
333                 KKASSERT(refs > 0);
334
335                 if (refs == 1) {
336                         chain = hammer2_chain_lastdrop(chain);
337                 } else {
338                         if (atomic_cmpset_int(&chain->refs, refs, refs - 1))
339                                 break;
340                         /* retry the same chain */
341                 }
342         }
343 }
344
345 /*
346  * Safe handling of the 1->0 transition on chain.  Returns a chain for
347  * recursive drop or NULL, possibly returning the same chain if the atomic
348  * op fails.
349  *
350  * Whem two chains need to be recursively dropped we use the chain
351  * we would otherwise free to placehold the additional chain.  It's a bit
352  * convoluted but we can't just recurse without potentially blowing out
353  * the kernel stack.
354  *
355  * The chain cannot be freed if it has a non-empty core (children) or
356  * it is not at the head of ownerq.
357  *
358  * The cst spinlock is allowed nest child-to-parent (not parent-to-child).
359  */
360 static
361 hammer2_chain_t *
362 hammer2_chain_lastdrop(hammer2_chain_t *chain)
363 {
364         hammer2_pfsmount_t *pmp;
365         hammer2_mount_t *hmp;
366         hammer2_chain_t *parent;
367         hammer2_chain_t *rdrop;
368
369         /*
370          * Spinlock the core and check to see if it is empty.  If it is
371          * not empty we leave chain intact with refs == 0.  The elements
372          * in core->rbtree are associated with other chains contemporary
373          * with ours but not with our chain directly.
374          */
375         spin_lock(&chain->core.cst.spin);
376
377         /*
378          * We can't free non-stale chains with children until we are
379          * able to free the children because there might be a flush
380          * dependency.  Flushes of stale children (which should also
381          * have their deleted flag set) short-cut recursive flush
382          * dependencies and can be freed here.  Any flushes which run
383          * through stale children due to the flush synchronization
384          * point should have a FLUSH_* bit set in the chain and not
385          * reach lastdrop at this time.
386          *
387          * NOTE: We return (chain) on failure to retry.
388          */
389         if (chain->core.chain_count) {
390                 if (atomic_cmpset_int(&chain->refs, 1, 0)) {
391                         spin_unlock(&chain->core.cst.spin);
392                         chain = NULL;   /* success */
393                 } else {
394                         spin_unlock(&chain->core.cst.spin);
395                 }
396                 return(chain);
397         }
398         /* no chains left under us */
399
400         /*
401          * chain->core has no children left so no accessors can get to our
402          * chain from there.  Now we have to lock the parent core to interlock
403          * remaining possible accessors that might bump chain's refs before
404          * we can safely drop chain's refs with intent to free the chain.
405          */
406         hmp = chain->hmp;
407         pmp = chain->pmp;       /* can be NULL */
408         rdrop = NULL;
409
410         /*
411          * Spinlock the parent and try to drop the last ref on chain.
412          * On success remove chain from its parent, otherwise return NULL.
413          *
414          * (normal core locks are top-down recursive but we define core
415          *  spinlocks as bottom-up recursive, so this is safe).
416          */
417         if ((parent = chain->parent) != NULL) {
418                 spin_lock(&parent->core.cst.spin);
419                 if (atomic_cmpset_int(&chain->refs, 1, 0) == 0) {
420                         /* 1->0 transition failed */
421                         spin_unlock(&parent->core.cst.spin);
422                         spin_unlock(&chain->core.cst.spin);
423                         return(chain);  /* retry */
424                 }
425
426                 /*
427                  * 1->0 transition successful, remove chain from its
428                  * above core.
429                  */
430                 if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
431                         RB_REMOVE(hammer2_chain_tree,
432                                   &parent->core.rbtree, chain);
433                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
434                         --parent->core.chain_count;
435                         chain->parent = NULL;
436                 }
437
438                 /*
439                  * If our chain was the last chain in the parent's core the
440                  * core is now empty and its parent might have to be
441                  * re-dropped if it has 0 refs.
442                  */
443                 if (parent->core.chain_count == 0) {
444                         rdrop = parent;
445                         if (atomic_cmpset_int(&rdrop->refs, 0, 1) == 0) {
446                                 rdrop = NULL;
447                         }
448                 }
449                 spin_unlock(&parent->core.cst.spin);
450                 parent = NULL;  /* safety */
451         }
452
453         /*
454          * Successful 1->0 transition and the chain can be destroyed now.
455          *
456          * We still have the core spinlock, and core's chain_count is 0.
457          * Any parent spinlock is gone.
458          */
459         spin_unlock(&chain->core.cst.spin);
460         KKASSERT(RB_EMPTY(&chain->core.rbtree) &&
461                  chain->core.chain_count == 0);
462         KKASSERT(chain->core.cst.count == 0);
463         KKASSERT(chain->core.cst.upgrade == 0);
464
465         /*
466          * All spin locks are gone, finish freeing stuff.
467          */
468         KKASSERT((chain->flags & (HAMMER2_CHAIN_UPDATE |
469                                   HAMMER2_CHAIN_MODIFIED)) == 0);
470         hammer2_chain_drop_data(chain, 1);
471
472         KKASSERT(chain->dio == NULL);
473
474         /*
475          * Once chain resources are gone we can use the now dead chain
476          * structure to placehold what might otherwise require a recursive
477          * drop, because we have potentially two things to drop and can only
478          * return one directly.
479          */
480         if (chain->flags & HAMMER2_CHAIN_ALLOCATED) {
481                 chain->flags &= ~HAMMER2_CHAIN_ALLOCATED;
482                 chain->hmp = NULL;
483                 kfree(chain, hmp->mchain);
484         }
485
486         /*
487          * Possible chaining loop when parent re-drop needed.
488          */
489         return(rdrop);
490 }
491
492 /*
493  * On either last lock release or last drop
494  */
495 static void
496 hammer2_chain_drop_data(hammer2_chain_t *chain, int lastdrop)
497 {
498         /*hammer2_mount_t *hmp = chain->hmp;*/
499
500         switch(chain->bref.type) {
501         case HAMMER2_BREF_TYPE_VOLUME:
502         case HAMMER2_BREF_TYPE_FREEMAP:
503                 if (lastdrop)
504                         chain->data = NULL;
505                 break;
506         default:
507                 KKASSERT(chain->data == NULL);
508                 break;
509         }
510 }
511
512 /*
513  * Ref and lock a chain element, acquiring its data with I/O if necessary,
514  * and specify how you would like the data to be resolved.
515  *
516  * Returns 0 on success or an error code if the data could not be acquired.
517  * The chain element is locked on return regardless of whether an error
518  * occurred or not.
519  *
520  * The lock is allowed to recurse, multiple locking ops will aggregate
521  * the requested resolve types.  Once data is assigned it will not be
522  * removed until the last unlock.
523  *
524  * HAMMER2_RESOLVE_NEVER - Do not resolve the data element.
525  *                         (typically used to avoid device/logical buffer
526  *                          aliasing for data)
527  *
528  * HAMMER2_RESOLVE_MAYBE - Do not resolve data elements for chains in
529  *                         the INITIAL-create state (indirect blocks only).
530  *
531  *                         Do not resolve data elements for DATA chains.
532  *                         (typically used to avoid device/logical buffer
533  *                          aliasing for data)
534  *
535  * HAMMER2_RESOLVE_ALWAYS- Always resolve the data element.
536  *
537  * HAMMER2_RESOLVE_SHARED- (flag) The chain is locked shared, otherwise
538  *                         it will be locked exclusive.
539  *
540  * NOTE: Embedded elements (volume header, inodes) are always resolved
541  *       regardless.
542  *
543  * NOTE: Specifying HAMMER2_RESOLVE_ALWAYS on a newly-created non-embedded
544  *       element will instantiate and zero its buffer, and flush it on
545  *       release.
546  *
547  * NOTE: (data) elements are normally locked RESOLVE_NEVER or RESOLVE_MAYBE
548  *       so as not to instantiate a device buffer, which could alias against
549  *       a logical file buffer.  However, if ALWAYS is specified the
550  *       device buffer will be instantiated anyway.
551  *
552  * WARNING! If data must be fetched a shared lock will temporarily be
553  *          upgraded to exclusive.  However, a deadlock can occur if
554  *          the caller owns more than one shared lock.
555  */
556 int
557 hammer2_chain_lock(hammer2_chain_t *chain, int how)
558 {
559         hammer2_mount_t *hmp;
560         hammer2_blockref_t *bref;
561         ccms_state_t ostate;
562         char *bdata;
563         int error;
564
565         /*
566          * Ref and lock the element.  Recursive locks are allowed.
567          */
568         if ((how & HAMMER2_RESOLVE_NOREF) == 0)
569                 hammer2_chain_ref(chain);
570         atomic_add_int(&chain->lockcnt, 1);
571
572         hmp = chain->hmp;
573         KKASSERT(hmp != NULL);
574
575         /*
576          * Get the appropriate lock.
577          */
578         if (how & HAMMER2_RESOLVE_SHARED)
579                 ccms_thread_lock(&chain->core.cst, CCMS_STATE_SHARED);
580         else
581                 ccms_thread_lock(&chain->core.cst, CCMS_STATE_EXCLUSIVE);
582
583         /*
584          * If we already have a valid data pointer no further action is
585          * necessary.
586          */
587         if (chain->data)
588                 return (0);
589
590         /*
591          * Do we have to resolve the data?
592          */
593         switch(how & HAMMER2_RESOLVE_MASK) {
594         case HAMMER2_RESOLVE_NEVER:
595                 return(0);
596         case HAMMER2_RESOLVE_MAYBE:
597                 if (chain->flags & HAMMER2_CHAIN_INITIAL)
598                         return(0);
599                 if (chain->bref.type == HAMMER2_BREF_TYPE_DATA)
600                         return(0);
601 #if 0
602                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE)
603                         return(0);
604                 if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF)
605                         return(0);
606 #endif
607                 /* fall through */
608         case HAMMER2_RESOLVE_ALWAYS:
609                 break;
610         }
611
612         /*
613          * Upgrade to an exclusive lock so we can safely manipulate the
614          * buffer cache.  If another thread got to it before us we
615          * can just return.
616          */
617         ostate = ccms_thread_lock_upgrade(&chain->core.cst);
618         if (chain->data) {
619                 ccms_thread_lock_downgrade(&chain->core.cst, ostate);
620                 return (0);
621         }
622
623         /*
624          * We must resolve to a device buffer, either by issuing I/O or
625          * by creating a zero-fill element.  We do not mark the buffer
626          * dirty when creating a zero-fill element (the hammer2_chain_modify()
627          * API must still be used to do that).
628          *
629          * The device buffer is variable-sized in powers of 2 down
630          * to HAMMER2_MIN_ALLOC (typically 1K).  A 64K physical storage
631          * chunk always contains buffers of the same size. (XXX)
632          *
633          * The minimum physical IO size may be larger than the variable
634          * block size.
635          */
636         bref = &chain->bref;
637
638         /*
639          * The getblk() optimization can only be used on newly created
640          * elements if the physical block size matches the request.
641          */
642         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
643                 error = hammer2_io_new(hmp, bref->data_off, chain->bytes,
644                                         &chain->dio);
645         } else {
646                 error = hammer2_io_bread(hmp, bref->data_off, chain->bytes,
647                                          &chain->dio);
648                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
649         }
650
651         if (error) {
652                 kprintf("hammer2_chain_lock: I/O error %016jx: %d\n",
653                         (intmax_t)bref->data_off, error);
654                 hammer2_io_bqrelse(&chain->dio);
655                 ccms_thread_lock_downgrade(&chain->core.cst, ostate);
656                 return (error);
657         }
658
659 #if 0
660         /*
661          * No need for this, always require that hammer2_chain_modify()
662          * be called before any modifying operations, which ensures that
663          * the underlying dio is dirty.
664          */
665         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) &&
666             !hammer2_io_isdirty(chain->dio)) {
667                 hammer2_io_setdirty(chain->dio);
668         }
669 #endif
670
671         /*
672          * Clear INITIAL.  In this case we used io_new() and the buffer has
673          * been zero'd and marked dirty.
674          */
675         bdata = hammer2_io_data(chain->dio, chain->bref.data_off);
676         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
677                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
678                 chain->bref.flags |= HAMMER2_BREF_FLAG_ZERO;
679         } else if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
680                 /*
681                  * check data not currently synchronized due to
682                  * modification.  XXX assumes data stays in the buffer
683                  * cache, which might not be true (need biodep on flush
684                  * to calculate crc?  or simple crc?).
685                  */
686         } else {
687                 if (hammer2_chain_testcheck(chain, bdata) == 0) {
688                         kprintf("chain %016jx.%02x meth=%02x CHECK FAIL %08x (flags=%08x)\n",
689
690                                 chain->bref.data_off,
691                                 chain->bref.type,
692                                 chain->bref.methods,
693                                 hammer2_icrc32(bdata, chain->bytes),
694                                 chain->flags);
695                 }
696         }
697
698         /*
699          * Setup the data pointer, either pointing it to an embedded data
700          * structure and copying the data from the buffer, or pointing it
701          * into the buffer.
702          *
703          * The buffer is not retained when copying to an embedded data
704          * structure in order to avoid potential deadlocks or recursions
705          * on the same physical buffer.
706          */
707         switch (bref->type) {
708         case HAMMER2_BREF_TYPE_VOLUME:
709         case HAMMER2_BREF_TYPE_FREEMAP:
710                 /*
711                  * Copy data from bp to embedded buffer
712                  */
713                 panic("hammer2_chain_lock: called on unresolved volume header");
714                 break;
715         case HAMMER2_BREF_TYPE_INODE:
716         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
717         case HAMMER2_BREF_TYPE_INDIRECT:
718         case HAMMER2_BREF_TYPE_DATA:
719         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
720         default:
721                 /*
722                  * Point data at the device buffer and leave dio intact.
723                  */
724                 chain->data = (void *)bdata;
725                 break;
726         }
727         ccms_thread_lock_downgrade(&chain->core.cst, ostate);
728         return (0);
729 }
730
731 /*
732  * Unlock and deref a chain element.
733  *
734  * On the last lock release any non-embedded data (chain->dio) will be
735  * retired.
736  */
737 void
738 hammer2_chain_unlock(hammer2_chain_t *chain)
739 {
740         ccms_state_t ostate;
741         long *counterp;
742         u_int lockcnt;
743
744         /*
745          * The core->cst lock can be shared across several chains so we
746          * need to track the per-chain lockcnt separately.
747          *
748          * If multiple locks are present (or being attempted) on this
749          * particular chain we can just unlock, drop refs, and return.
750          *
751          * Otherwise fall-through on the 1->0 transition.
752          */
753         for (;;) {
754                 lockcnt = chain->lockcnt;
755                 KKASSERT(lockcnt > 0);
756                 cpu_ccfence();
757                 if (lockcnt > 1) {
758                         if (atomic_cmpset_int(&chain->lockcnt,
759                                               lockcnt, lockcnt - 1)) {
760                                 ccms_thread_unlock(&chain->core.cst);
761                                 hammer2_chain_drop(chain);
762                                 return;
763                         }
764                 } else {
765                         if (atomic_cmpset_int(&chain->lockcnt, 1, 0))
766                                 break;
767                 }
768                 /* retry */
769         }
770
771         /*
772          * On the 1->0 transition we upgrade the core lock (if necessary)
773          * to exclusive for terminal processing.  If after upgrading we find
774          * that lockcnt is non-zero, another thread is racing us and will
775          * handle the unload for us later on, so just cleanup and return
776          * leaving the data/io intact
777          *
778          * Otherwise if lockcnt is still 0 it is possible for it to become
779          * non-zero and race, but since we hold the core->cst lock
780          * exclusively all that will happen is that the chain will be
781          * reloaded after we unload it.
782          */
783         ostate = ccms_thread_lock_upgrade(&chain->core.cst);
784         if (chain->lockcnt) {
785                 ccms_thread_unlock_upgraded(&chain->core.cst, ostate);
786                 hammer2_chain_drop(chain);
787                 return;
788         }
789
790         /*
791          * Shortcut the case if the data is embedded or not resolved.
792          *
793          * Do NOT NULL out chain->data (e.g. inode data), it might be
794          * dirty.
795          */
796         if (chain->dio == NULL) {
797                 if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0)
798                         hammer2_chain_drop_data(chain, 0);
799                 ccms_thread_unlock_upgraded(&chain->core.cst, ostate);
800                 hammer2_chain_drop(chain);
801                 return;
802         }
803
804         /*
805          * Statistics
806          */
807         if (hammer2_io_isdirty(chain->dio) == 0) {
808                 ;
809         } else if (chain->flags & HAMMER2_CHAIN_IOFLUSH) {
810                 switch(chain->bref.type) {
811                 case HAMMER2_BREF_TYPE_DATA:
812                         counterp = &hammer2_ioa_file_write;
813                         break;
814                 case HAMMER2_BREF_TYPE_INODE:
815                         counterp = &hammer2_ioa_meta_write;
816                         break;
817                 case HAMMER2_BREF_TYPE_INDIRECT:
818                         counterp = &hammer2_ioa_indr_write;
819                         break;
820                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
821                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
822                         counterp = &hammer2_ioa_fmap_write;
823                         break;
824                 default:
825                         counterp = &hammer2_ioa_volu_write;
826                         break;
827                 }
828                 *counterp += chain->bytes;
829         } else {
830                 switch(chain->bref.type) {
831                 case HAMMER2_BREF_TYPE_DATA:
832                         counterp = &hammer2_iod_file_write;
833                         break;
834                 case HAMMER2_BREF_TYPE_INODE:
835                         counterp = &hammer2_iod_meta_write;
836                         break;
837                 case HAMMER2_BREF_TYPE_INDIRECT:
838                         counterp = &hammer2_iod_indr_write;
839                         break;
840                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
841                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
842                         counterp = &hammer2_iod_fmap_write;
843                         break;
844                 default:
845                         counterp = &hammer2_iod_volu_write;
846                         break;
847                 }
848                 *counterp += chain->bytes;
849         }
850
851         /*
852          * Clean out the dio.
853          *
854          * If a device buffer was used for data be sure to destroy the
855          * buffer when we are done to avoid aliases (XXX what about the
856          * underlying VM pages?).
857          *
858          * NOTE: Freemap leaf's use reserved blocks and thus no aliasing
859          *       is possible.
860          *
861          * NOTE: The isdirty check tracks whether we have to bdwrite() the
862          *       buffer or not.  The buffer might already be dirty.  The
863          *       flag is re-set when chain_modify() is called, even if
864          *       MODIFIED is already set, allowing the OS to retire the
865          *       buffer independent of a hammer2 flush.
866          */
867         chain->data = NULL;
868         if ((chain->flags & HAMMER2_CHAIN_IOFLUSH) &&
869             hammer2_io_isdirty(chain->dio)) {
870                 hammer2_io_bawrite(&chain->dio);
871         } else {
872                 hammer2_io_bqrelse(&chain->dio);
873         }
874         ccms_thread_unlock_upgraded(&chain->core.cst, ostate);
875         hammer2_chain_drop(chain);
876 }
877
878 /*
879  * This counts the number of live blockrefs in a block array and
880  * also calculates the point at which all remaining blockrefs are empty.
881  * This routine can only be called on a live chain (DUPLICATED flag not set).
882  *
883  * NOTE: Flag is not set until after the count is complete, allowing
884  *       callers to test the flag without holding the spinlock.
885  *
886  * NOTE: If base is NULL the related chain is still in the INITIAL
887  *       state and there are no blockrefs to count.
888  *
889  * NOTE: live_count may already have some counts accumulated due to
890  *       creation and deletion and could even be initially negative.
891  */
892 void
893 hammer2_chain_countbrefs(hammer2_chain_t *chain,
894                          hammer2_blockref_t *base, int count)
895 {
896         spin_lock(&chain->core.cst.spin);
897         if ((chain->core.flags & HAMMER2_CORE_COUNTEDBREFS) == 0) {
898                 if (base) {
899                         while (--count >= 0) {
900                                 if (base[count].type)
901                                         break;
902                         }
903                         chain->core.live_zero = count + 1;
904                         while (count >= 0) {
905                                 if (base[count].type)
906                                         atomic_add_int(&chain->core.live_count,
907                                                        1);
908                                 --count;
909                         }
910                 } else {
911                         chain->core.live_zero = 0;
912                 }
913                 /* else do not modify live_count */
914                 atomic_set_int(&chain->core.flags, HAMMER2_CORE_COUNTEDBREFS);
915         }
916         spin_unlock(&chain->core.cst.spin);
917 }
918
919 /*
920  * Resize the chain's physical storage allocation in-place.  This function does
921  * not adjust the data pointer and must be followed by (typically) a
922  * hammer2_chain_modify() call to copy any old data over and adjust the
923  * data pointer.
924  *
925  * Chains can be resized smaller without reallocating the storage.  Resizing
926  * larger will reallocate the storage.  Excess or prior storage is reclaimed
927  * asynchronously at a later time.
928  *
929  * Must be passed an exclusively locked parent and chain.
930  *
931  * This function is mostly used with DATA blocks locked RESOLVE_NEVER in order
932  * to avoid instantiating a device buffer that conflicts with the vnode data
933  * buffer.  However, because H2 can compress or encrypt data, the chain may
934  * have a dio assigned to it in those situations, and they do not conflict.
935  *
936  * XXX return error if cannot resize.
937  */
938 void
939 hammer2_chain_resize(hammer2_trans_t *trans, hammer2_inode_t *ip,
940                      hammer2_chain_t *parent, hammer2_chain_t *chain,
941                      int nradix, int flags)
942 {
943         hammer2_mount_t *hmp;
944         size_t obytes;
945         size_t nbytes;
946
947         hmp = chain->hmp;
948
949         /*
950          * Only data and indirect blocks can be resized for now.
951          * (The volu root, inodes, and freemap elements use a fixed size).
952          */
953         KKASSERT(chain != &hmp->vchain);
954         KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA ||
955                  chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT);
956
957         /*
958          * Nothing to do if the element is already the proper size
959          */
960         obytes = chain->bytes;
961         nbytes = 1U << nradix;
962         if (obytes == nbytes)
963                 return;
964         chain->data_count += (ssize_t)(nbytes - obytes);
965
966         /*
967          * Make sure the old data is instantiated so we can copy it.  If this
968          * is a data block, the device data may be superfluous since the data
969          * might be in a logical block, but compressed or encrypted data is
970          * another matter.
971          *
972          * NOTE: The modify will set BMAPUPD for us if BMAPPED is set.
973          */
974         hammer2_chain_modify(trans, chain, 0);
975
976         /*
977          * Relocate the block, even if making it smaller (because different
978          * block sizes may be in different regions).
979          *
980          * (data blocks only, we aren't copying the storage here).
981          */
982         hammer2_freemap_alloc(trans, chain, nbytes);
983         chain->bytes = nbytes;
984         /*ip->delta_dcount += (ssize_t)(nbytes - obytes);*/ /* XXX atomic */
985
986         /*
987          * We don't want the followup chain_modify() to try to copy data
988          * from the old (wrong-sized) buffer.  It won't know how much to
989          * copy.  This case should only occur during writes when the
990          * originator already has the data to write in-hand.
991          */
992         if (chain->dio) {
993                 KKASSERT(chain->bref.type == HAMMER2_BREF_TYPE_DATA);
994                 hammer2_io_brelse(&chain->dio);
995                 chain->data = NULL;
996         }
997 }
998
999 #if 0
1000
1001 /*
1002  * REMOVED - see cluster code
1003  *
1004  * Set a chain modified, making it read-write and duplicating it if necessary.
1005  * This function will assign a new physical block to the chain if necessary
1006  *
1007  * Duplication of already-modified chains is possible when the modification
1008  * crosses a flush synchronization boundary.
1009  *
1010  * Non-data blocks - The chain should be locked to at least the RESOLVE_MAYBE
1011  *                   level or the COW operation will not work.
1012  *
1013  * Data blocks     - The chain is usually locked RESOLVE_NEVER so as not to
1014  *                   run the data through the device buffers.
1015  *
1016  * This function may return a different chain than was passed, in which case
1017  * the old chain will be unlocked and the new chain will be locked.
1018  *
1019  * ip->chain may be adjusted by hammer2_chain_modify_ip().
1020  */
1021 hammer2_inode_data_t *
1022 hammer2_chain_modify_ip(hammer2_trans_t *trans, hammer2_inode_t *ip,
1023                         hammer2_chain_t **chainp, int flags)
1024 {
1025         atomic_set_int(&ip->flags, HAMMER2_INODE_MODIFIED);
1026         hammer2_chain_modify(trans, chainp, flags);
1027         if (ip->chain != *chainp)
1028                 hammer2_inode_repoint(ip, NULL, *chainp);
1029         if (ip->vp)
1030                 vsetisdirty(ip->vp);
1031         return(&ip->chain->data->ipdata);
1032 }
1033
1034 #endif
1035
1036 void
1037 hammer2_chain_modify(hammer2_trans_t *trans, hammer2_chain_t *chain, int flags)
1038 {
1039         hammer2_blockref_t obref;
1040         hammer2_mount_t *hmp;
1041         hammer2_io_t *dio;
1042         int error;
1043         int wasinitial;
1044         int newmod;
1045         char *bdata;
1046
1047         hmp = chain->hmp;
1048         obref = chain->bref;
1049
1050         /*
1051          * Data is not optional for freemap chains (we must always be sure
1052          * to copy the data on COW storage allocations).
1053          */
1054         if (chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
1055             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
1056                 KKASSERT((chain->flags & HAMMER2_CHAIN_INITIAL) ||
1057                          (flags & HAMMER2_MODIFY_OPTDATA) == 0);
1058         }
1059
1060         /*
1061          * Data must be resolved if already assigned unless explicitly
1062          * flagged otherwise.
1063          */
1064         if (chain->data == NULL && (flags & HAMMER2_MODIFY_OPTDATA) == 0 &&
1065             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
1066                 hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
1067                 hammer2_chain_unlock(chain);
1068         }
1069
1070         /*
1071          * Otherwise do initial-chain handling.  Set MODIFIED to indicate
1072          * that the chain has been modified.  Set UPDATE to ensure that
1073          * the blockref is updated in the parent.
1074          */
1075         if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0) {
1076                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1077                 hammer2_chain_ref(chain);
1078                 hammer2_pfs_memory_inc(chain->pmp);
1079                 newmod = 1;
1080         } else {
1081                 newmod = 0;
1082         }
1083         if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0) {
1084                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
1085                 hammer2_chain_ref(chain);
1086         }
1087
1088         /*
1089          * The modification or re-modification requires an allocation and
1090          * possible COW.
1091          *
1092          * We normally always allocate new storage here.  If storage exists
1093          * and MODIFY_NOREALLOC is passed in, we do not allocate new storage.
1094          */
1095         if (chain != &hmp->vchain && chain != &hmp->fchain) {
1096                 if ((chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX) == 0 ||
1097                      ((flags & HAMMER2_MODIFY_NOREALLOC) == 0 && newmod)
1098                 ) {
1099                         hammer2_freemap_alloc(trans, chain, chain->bytes);
1100                         /* XXX failed allocation */
1101                 }
1102         }
1103
1104         /*
1105          * Set BMAPUPD to tell the flush code that an existing blockmap entry
1106          * requires updating as well as to tell the delete code that the
1107          * chain's blockref might not exactly match (in terms of physical size
1108          * or block offset) the one in the parent's blocktable.  The base key
1109          * of course will still match.
1110          */
1111         if (chain->flags & HAMMER2_CHAIN_BMAPPED)
1112                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPUPD);
1113
1114         /*
1115          * Short-cut data blocks which the caller does not need an actual
1116          * data reference to (aka OPTDATA), as long as the chain does not
1117          * already have a data pointer to the data.  This generally means
1118          * that the modifications are being done via the logical buffer cache.
1119          * The INITIAL flag relates only to the device data buffer and thus
1120          * remains unchange in this situation.
1121          */
1122         if (chain->bref.type == HAMMER2_BREF_TYPE_DATA &&
1123             (flags & HAMMER2_MODIFY_OPTDATA) &&
1124             chain->data == NULL) {
1125                 goto skip2;
1126         }
1127
1128         /*
1129          * Clearing the INITIAL flag (for indirect blocks) indicates that
1130          * we've processed the uninitialized storage allocation.
1131          *
1132          * If this flag is already clear we are likely in a copy-on-write
1133          * situation but we have to be sure NOT to bzero the storage if
1134          * no data is present.
1135          */
1136         if (chain->flags & HAMMER2_CHAIN_INITIAL) {
1137                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1138                 wasinitial = 1;
1139         } else {
1140                 wasinitial = 0;
1141         }
1142
1143         /*
1144          * Instantiate data buffer and possibly execute COW operation
1145          */
1146         switch(chain->bref.type) {
1147         case HAMMER2_BREF_TYPE_VOLUME:
1148         case HAMMER2_BREF_TYPE_FREEMAP:
1149                 /*
1150                  * The data is embedded, no copy-on-write operation is
1151                  * needed.
1152                  */
1153                 KKASSERT(chain->dio == NULL);
1154                 break;
1155         case HAMMER2_BREF_TYPE_INODE:
1156         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1157         case HAMMER2_BREF_TYPE_DATA:
1158         case HAMMER2_BREF_TYPE_INDIRECT:
1159         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1160                 /*
1161                  * Perform the copy-on-write operation
1162                  *
1163                  * zero-fill or copy-on-write depending on whether
1164                  * chain->data exists or not and set the dirty state for
1165                  * the new buffer.  hammer2_io_new() will handle the
1166                  * zero-fill.
1167                  */
1168                 KKASSERT(chain != &hmp->vchain && chain != &hmp->fchain);
1169
1170                 if (wasinitial) {
1171                         error = hammer2_io_new(hmp, chain->bref.data_off,
1172                                                chain->bytes, &dio);
1173                 } else {
1174                         error = hammer2_io_bread(hmp, chain->bref.data_off,
1175                                                  chain->bytes, &dio);
1176                 }
1177                 hammer2_adjreadcounter(&chain->bref, chain->bytes);
1178                 KKASSERT(error == 0);
1179
1180                 bdata = hammer2_io_data(dio, chain->bref.data_off);
1181
1182                 if (chain->data) {
1183                         KKASSERT(chain->dio != NULL);
1184                         if (chain->data != (void *)bdata) {
1185                                 bcopy(chain->data, bdata, chain->bytes);
1186                         }
1187                 } else if (wasinitial == 0) {
1188                         /*
1189                          * We have a problem.  We were asked to COW but
1190                          * we don't have any data to COW with!
1191                          */
1192                         panic("hammer2_chain_modify: having a COW %p\n",
1193                               chain);
1194                 }
1195
1196                 /*
1197                  * Retire the old buffer, replace with the new.  Dirty or
1198                  * redirty the new buffer.
1199                  *
1200                  * WARNING! The system buffer cache may have already flushed
1201                  *          the buffer, so we must be sure to [re]dirty it
1202                  *          for further modification.
1203                  */
1204                 if (chain->dio)
1205                         hammer2_io_brelse(&chain->dio);
1206                 chain->data = (void *)bdata;
1207                 chain->dio = dio;
1208                 hammer2_io_setdirty(dio);       /* modified by bcopy above */
1209                 break;
1210         default:
1211                 panic("hammer2_chain_modify: illegal non-embedded type %d",
1212                       chain->bref.type);
1213                 break;
1214
1215         }
1216 skip2:
1217         /*
1218          * setflush on parent indicating that the parent must recurse down
1219          * to us.  Do not call on chain itself which might already have it
1220          * set.
1221          */
1222         if (chain->parent)
1223                 hammer2_chain_setflush(trans, chain->parent);
1224
1225         /*
1226          * Adjust the freemap bitmap to indicate that the related blocks
1227          * MIGHT be freeable.  Bulkfree must still determine that the blocks
1228          * are actually freeable.
1229          */
1230         if (obref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE &&
1231             obref.type != HAMMER2_BREF_TYPE_FREEMAP_LEAF &&
1232             (obref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
1233                 hammer2_freemap_adjust(trans, hmp,
1234                                        &obref, HAMMER2_FREEMAP_DOMAYFREE);
1235         }
1236 }
1237
1238 /*
1239  * Volume header data locks
1240  */
1241 void
1242 hammer2_voldata_lock(hammer2_mount_t *hmp)
1243 {
1244         lockmgr(&hmp->vollk, LK_EXCLUSIVE);
1245 }
1246
1247 void
1248 hammer2_voldata_unlock(hammer2_mount_t *hmp)
1249 {
1250         lockmgr(&hmp->vollk, LK_RELEASE);
1251 }
1252
1253 void
1254 hammer2_voldata_modify(hammer2_mount_t *hmp)
1255 {
1256         if ((hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) == 0) {
1257                 atomic_set_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1258                 hammer2_chain_ref(&hmp->vchain);
1259                 hammer2_pfs_memory_inc(hmp->vchain.pmp);
1260         }
1261 }
1262
1263 /*
1264  * This function returns the chain at the nearest key within the specified
1265  * range.  The returned chain will be referenced but not locked.
1266  *
1267  * This function will recurse through chain->rbtree as necessary and will
1268  * return a *key_nextp suitable for iteration.  *key_nextp is only set if
1269  * the iteration value is less than the current value of *key_nextp.
1270  *
1271  * The caller should use (*key_nextp) to calculate the actual range of
1272  * the returned element, which will be (key_beg to *key_nextp - 1), because
1273  * there might be another element which is superior to the returned element
1274  * and overlaps it.
1275  *
1276  * (*key_nextp) can be passed as key_beg in an iteration only while non-NULL
1277  * chains continue to be returned.  On EOF (*key_nextp) may overflow since
1278  * it will wind up being (key_end + 1).
1279  *
1280  * WARNING!  Must be called with child's spinlock held.  Spinlock remains
1281  *           held through the operation.
1282  */
1283 struct hammer2_chain_find_info {
1284         hammer2_chain_t         *best;
1285         hammer2_key_t           key_beg;
1286         hammer2_key_t           key_end;
1287         hammer2_key_t           key_next;
1288 };
1289
1290 static int hammer2_chain_find_cmp(hammer2_chain_t *child, void *data);
1291 static int hammer2_chain_find_callback(hammer2_chain_t *child, void *data);
1292
1293 static
1294 hammer2_chain_t *
1295 hammer2_chain_find(hammer2_chain_t *parent, hammer2_key_t *key_nextp,
1296                           hammer2_key_t key_beg, hammer2_key_t key_end)
1297 {
1298         struct hammer2_chain_find_info info;
1299
1300         info.best = NULL;
1301         info.key_beg = key_beg;
1302         info.key_end = key_end;
1303         info.key_next = *key_nextp;
1304
1305         RB_SCAN(hammer2_chain_tree, &parent->core.rbtree,
1306                 hammer2_chain_find_cmp, hammer2_chain_find_callback,
1307                 &info);
1308         *key_nextp = info.key_next;
1309 #if 0
1310         kprintf("chain_find %p %016jx:%016jx next=%016jx\n",
1311                 parent, key_beg, key_end, *key_nextp);
1312 #endif
1313
1314         return (info.best);
1315 }
1316
1317 static
1318 int
1319 hammer2_chain_find_cmp(hammer2_chain_t *child, void *data)
1320 {
1321         struct hammer2_chain_find_info *info = data;
1322         hammer2_key_t child_beg;
1323         hammer2_key_t child_end;
1324
1325         child_beg = child->bref.key;
1326         child_end = child_beg + ((hammer2_key_t)1 << child->bref.keybits) - 1;
1327
1328         if (child_end < info->key_beg)
1329                 return(-1);
1330         if (child_beg > info->key_end)
1331                 return(1);
1332         return(0);
1333 }
1334
1335 static
1336 int
1337 hammer2_chain_find_callback(hammer2_chain_t *child, void *data)
1338 {
1339         struct hammer2_chain_find_info *info = data;
1340         hammer2_chain_t *best;
1341         hammer2_key_t child_end;
1342
1343         /*
1344          * WARNING! Do not discard DUPLICATED chains, it is possible that
1345          *          we are catching an insertion half-way done.  If a
1346          *          duplicated chain turns out to be the best choice the
1347          *          caller will re-check its flags after locking it.
1348          *
1349          * WARNING! Layerq is scanned forwards, exact matches should keep
1350          *          the existing info->best.
1351          */
1352         if ((best = info->best) == NULL) {
1353                 /*
1354                  * No previous best.  Assign best
1355                  */
1356                 info->best = child;
1357         } else if (best->bref.key <= info->key_beg &&
1358                    child->bref.key <= info->key_beg) {
1359                 /*
1360                  * Illegal overlap.
1361                  */
1362                 KKASSERT(0);
1363                 /*info->best = child;*/
1364         } else if (child->bref.key < best->bref.key) {
1365                 /*
1366                  * Child has a nearer key and best is not flush with key_beg.
1367                  * Set best to child.  Truncate key_next to the old best key.
1368                  */
1369                 info->best = child;
1370                 if (info->key_next > best->bref.key || info->key_next == 0)
1371                         info->key_next = best->bref.key;
1372         } else if (child->bref.key == best->bref.key) {
1373                 /*
1374                  * If our current best is flush with the child then this
1375                  * is an illegal overlap.
1376                  *
1377                  * key_next will automatically be limited to the smaller of
1378                  * the two end-points.
1379                  */
1380                 KKASSERT(0);
1381                 info->best = child;
1382         } else {
1383                 /*
1384                  * Keep the current best but truncate key_next to the child's
1385                  * base.
1386                  *
1387                  * key_next will also automatically be limited to the smaller
1388                  * of the two end-points (probably not necessary for this case
1389                  * but we do it anyway).
1390                  */
1391                 if (info->key_next > child->bref.key || info->key_next == 0)
1392                         info->key_next = child->bref.key;
1393         }
1394
1395         /*
1396          * Always truncate key_next based on child's end-of-range.
1397          */
1398         child_end = child->bref.key + ((hammer2_key_t)1 << child->bref.keybits);
1399         if (child_end && (info->key_next > child_end || info->key_next == 0))
1400                 info->key_next = child_end;
1401
1402         return(0);
1403 }
1404
1405 /*
1406  * Retrieve the specified chain from a media blockref, creating the
1407  * in-memory chain structure which reflects it.
1408  *
1409  * To handle insertion races pass the INSERT_RACE flag along with the
1410  * generation number of the core.  NULL will be returned if the generation
1411  * number changes before we have a chance to insert the chain.  Insert
1412  * races can occur because the parent might be held shared.
1413  *
1414  * Caller must hold the parent locked shared or exclusive since we may
1415  * need the parent's bref array to find our block.
1416  *
1417  * WARNING! chain->pmp is left NULL if the bref represents a PFS mount
1418  *          point.
1419  */
1420 hammer2_chain_t *
1421 hammer2_chain_get(hammer2_chain_t *parent, int generation,
1422                   hammer2_blockref_t *bref)
1423 {
1424         hammer2_mount_t *hmp = parent->hmp;
1425         hammer2_chain_t *chain;
1426         int error;
1427
1428         /*
1429          * Allocate a chain structure representing the existing media
1430          * entry.  Resulting chain has one ref and is not locked.
1431          */
1432         if (bref->flags & HAMMER2_BREF_FLAG_PFSROOT)
1433                 chain = hammer2_chain_alloc(hmp, NULL, NULL, bref);
1434         else
1435                 chain = hammer2_chain_alloc(hmp, parent->pmp, NULL, bref);
1436         hammer2_chain_core_alloc(NULL, chain);
1437         /* ref'd chain returned */
1438
1439         /*
1440          * Flag that the chain is in the parent's blockmap so delete/flush
1441          * knows what to do with it.
1442          */
1443         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
1444
1445         /*
1446          * Link the chain into its parent.  A spinlock is required to safely
1447          * access the RBTREE, and it is possible to collide with another
1448          * hammer2_chain_get() operation because the caller might only hold
1449          * a shared lock on the parent.
1450          */
1451         KKASSERT(parent->refs > 0);
1452         error = hammer2_chain_insert(parent, chain,
1453                                      HAMMER2_CHAIN_INSERT_SPIN |
1454                                      HAMMER2_CHAIN_INSERT_RACE,
1455                                      generation);
1456         if (error) {
1457                 KKASSERT((chain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
1458                 kprintf("chain %p get race\n", chain);
1459                 hammer2_chain_drop(chain);
1460                 chain = NULL;
1461         } else {
1462                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
1463         }
1464
1465         /*
1466          * Return our new chain referenced but not locked, or NULL if
1467          * a race occurred.
1468          */
1469         return (chain);
1470 }
1471
1472 /*
1473  * Lookup initialization/completion API
1474  */
1475 hammer2_chain_t *
1476 hammer2_chain_lookup_init(hammer2_chain_t *parent, int flags)
1477 {
1478         if (flags & HAMMER2_LOOKUP_SHARED) {
1479                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS |
1480                                            HAMMER2_RESOLVE_SHARED);
1481         } else {
1482                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1483         }
1484         return (parent);
1485 }
1486
1487 void
1488 hammer2_chain_lookup_done(hammer2_chain_t *parent)
1489 {
1490         if (parent)
1491                 hammer2_chain_unlock(parent);
1492 }
1493
1494 static
1495 hammer2_chain_t *
1496 hammer2_chain_getparent(hammer2_chain_t **parentp, int how)
1497 {
1498         hammer2_chain_t *oparent;
1499         hammer2_chain_t *nparent;
1500
1501         /*
1502          * Be careful of order, oparent must be unlocked before nparent
1503          * is locked below to avoid a deadlock.
1504          */
1505         oparent = *parentp;
1506         spin_lock(&oparent->core.cst.spin);
1507         nparent = oparent->parent;
1508         hammer2_chain_ref(nparent);
1509         spin_unlock(&oparent->core.cst.spin);
1510         if (oparent) {
1511                 hammer2_chain_unlock(oparent);
1512                 oparent = NULL;
1513         }
1514
1515         hammer2_chain_lock(nparent, how | HAMMER2_RESOLVE_NOREF);
1516         *parentp = nparent;
1517
1518         return (nparent);
1519 }
1520
1521 /*
1522  * Locate the first chain whos key range overlaps (key_beg, key_end) inclusive.
1523  * (*parentp) typically points to an inode but can also point to a related
1524  * indirect block and this function will recurse upwards and find the inode
1525  * again.
1526  *
1527  * (*parentp) must be exclusively locked and referenced and can be an inode
1528  * or an existing indirect block within the inode.
1529  *
1530  * On return (*parentp) will be modified to point at the deepest parent chain
1531  * element encountered during the search, as a helper for an insertion or
1532  * deletion.   The new (*parentp) will be locked and referenced and the old
1533  * will be unlocked and dereferenced (no change if they are both the same).
1534  *
1535  * The matching chain will be returned exclusively locked.  If NOLOCK is
1536  * requested the chain will be returned only referenced.
1537  *
1538  * NULL is returned if no match was found, but (*parentp) will still
1539  * potentially be adjusted.
1540  *
1541  * On return (*key_nextp) will point to an iterative value for key_beg.
1542  * (If NULL is returned (*key_nextp) is set to key_end).
1543  *
1544  * This function will also recurse up the chain if the key is not within the
1545  * current parent's range.  (*parentp) can never be set to NULL.  An iteration
1546  * can simply allow (*parentp) to float inside the loop.
1547  *
1548  * NOTE!  chain->data is not always resolved.  By default it will not be
1549  *        resolved for BREF_TYPE_DATA, FREEMAP_NODE, or FREEMAP_LEAF.  Use
1550  *        HAMMER2_LOOKUP_ALWAYS to force resolution (but be careful w/
1551  *        BREF_TYPE_DATA as the device buffer can alias the logical file
1552  *        buffer).
1553  */
1554 hammer2_chain_t *
1555 hammer2_chain_lookup(hammer2_chain_t **parentp, hammer2_key_t *key_nextp,
1556                      hammer2_key_t key_beg, hammer2_key_t key_end,
1557                      int *cache_indexp, int flags, int *ddflagp)
1558 {
1559         hammer2_mount_t *hmp;
1560         hammer2_chain_t *parent;
1561         hammer2_chain_t *chain;
1562         hammer2_blockref_t *base;
1563         hammer2_blockref_t *bref;
1564         hammer2_blockref_t bcopy;
1565         hammer2_key_t scan_beg;
1566         hammer2_key_t scan_end;
1567         int count = 0;
1568         int how_always = HAMMER2_RESOLVE_ALWAYS;
1569         int how_maybe = HAMMER2_RESOLVE_MAYBE;
1570         int how;
1571         int generation;
1572         int maxloops = 300000;
1573
1574         *ddflagp = 0;
1575         if (flags & HAMMER2_LOOKUP_ALWAYS) {
1576                 how_maybe = how_always;
1577                 how = HAMMER2_RESOLVE_ALWAYS;
1578         } else if (flags & (HAMMER2_LOOKUP_NODATA | HAMMER2_LOOKUP_NOLOCK)) {
1579                 how = HAMMER2_RESOLVE_NEVER;
1580         } else {
1581                 how = HAMMER2_RESOLVE_MAYBE;
1582         }
1583         if (flags & (HAMMER2_LOOKUP_SHARED | HAMMER2_LOOKUP_NOLOCK)) {
1584                 how_maybe |= HAMMER2_RESOLVE_SHARED;
1585                 how_always |= HAMMER2_RESOLVE_SHARED;
1586                 how |= HAMMER2_RESOLVE_SHARED;
1587         }
1588
1589         /*
1590          * Recurse (*parentp) upward if necessary until the parent completely
1591          * encloses the key range or we hit the inode.
1592          *
1593          * This function handles races against the flusher doing a delete-
1594          * duplicate above us and re-homes the parent to the duplicate in
1595          * that case, otherwise we'd wind up recursing down a stale chain.
1596          */
1597         parent = *parentp;
1598         hmp = parent->hmp;
1599
1600         while (parent->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1601                parent->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
1602                 scan_beg = parent->bref.key;
1603                 scan_end = scan_beg +
1604                            ((hammer2_key_t)1 << parent->bref.keybits) - 1;
1605                 if (key_beg >= scan_beg && key_end <= scan_end)
1606                         break;
1607                 parent = hammer2_chain_getparent(parentp, how_maybe);
1608         }
1609
1610 again:
1611         if (--maxloops == 0)
1612                 panic("hammer2_chain_lookup: maxloops");
1613         /*
1614          * Locate the blockref array.  Currently we do a fully associative
1615          * search through the array.
1616          */
1617         switch(parent->bref.type) {
1618         case HAMMER2_BREF_TYPE_INODE:
1619                 /*
1620                  * Special shortcut for embedded data returns the inode
1621                  * itself.  Callers must detect this condition and access
1622                  * the embedded data (the strategy code does this for us).
1623                  *
1624                  * This is only applicable to regular files and softlinks.
1625                  */
1626                 if (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
1627                         if (flags & HAMMER2_LOOKUP_NOLOCK)
1628                                 hammer2_chain_ref(parent);
1629                         else
1630                                 hammer2_chain_lock(parent, how_always);
1631                         *key_nextp = key_end + 1;
1632                         *ddflagp = 1;
1633                         return (parent);
1634                 }
1635                 base = &parent->data->ipdata.u.blockset.blockref[0];
1636                 count = HAMMER2_SET_COUNT;
1637                 break;
1638         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1639         case HAMMER2_BREF_TYPE_INDIRECT:
1640                 /*
1641                  * Handle MATCHIND on the parent
1642                  */
1643                 if (flags & HAMMER2_LOOKUP_MATCHIND) {
1644                         scan_beg = parent->bref.key;
1645                         scan_end = scan_beg +
1646                                ((hammer2_key_t)1 << parent->bref.keybits) - 1;
1647                         if (key_beg == scan_beg && key_end == scan_end) {
1648                                 chain = parent;
1649                                 hammer2_chain_lock(chain, how_maybe);
1650                                 *key_nextp = scan_end + 1;
1651                                 goto done;
1652                         }
1653                 }
1654                 /*
1655                  * Optimize indirect blocks in the INITIAL state to avoid
1656                  * I/O.
1657                  */
1658                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
1659                         base = NULL;
1660                 } else {
1661                         if (parent->data == NULL)
1662                                 panic("parent->data is NULL");
1663                         base = &parent->data->npdata[0];
1664                 }
1665                 count = parent->bytes / sizeof(hammer2_blockref_t);
1666                 break;
1667         case HAMMER2_BREF_TYPE_VOLUME:
1668                 base = &hmp->voldata.sroot_blockset.blockref[0];
1669                 count = HAMMER2_SET_COUNT;
1670                 break;
1671         case HAMMER2_BREF_TYPE_FREEMAP:
1672                 base = &hmp->voldata.freemap_blockset.blockref[0];
1673                 count = HAMMER2_SET_COUNT;
1674                 break;
1675         default:
1676                 panic("hammer2_chain_lookup: unrecognized blockref type: %d",
1677                       parent->bref.type);
1678                 base = NULL;    /* safety */
1679                 count = 0;      /* safety */
1680         }
1681
1682         /*
1683          * Merged scan to find next candidate.
1684          *
1685          * hammer2_base_*() functions require the parent->core.live_* fields
1686          * to be synchronized.
1687          *
1688          * We need to hold the spinlock to access the block array and RB tree
1689          * and to interlock chain creation.
1690          */
1691         if ((parent->core.flags & HAMMER2_CORE_COUNTEDBREFS) == 0)
1692                 hammer2_chain_countbrefs(parent, base, count);
1693
1694         /*
1695          * Combined search
1696          */
1697         spin_lock(&parent->core.cst.spin);
1698         chain = hammer2_combined_find(parent, base, count,
1699                                       cache_indexp, key_nextp,
1700                                       key_beg, key_end,
1701                                       &bref);
1702         generation = parent->core.generation;
1703
1704         /*
1705          * Exhausted parent chain, iterate.
1706          */
1707         if (bref == NULL) {
1708                 spin_unlock(&parent->core.cst.spin);
1709                 if (key_beg == key_end) /* short cut single-key case */
1710                         return (NULL);
1711
1712                 /*
1713                  * Stop if we reached the end of the iteration.
1714                  */
1715                 if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
1716                     parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
1717                         return (NULL);
1718                 }
1719
1720                 /*
1721                  * Calculate next key, stop if we reached the end of the
1722                  * iteration, otherwise go up one level and loop.
1723                  */
1724                 key_beg = parent->bref.key +
1725                           ((hammer2_key_t)1 << parent->bref.keybits);
1726                 if (key_beg == 0 || key_beg > key_end)
1727                         return (NULL);
1728                 parent = hammer2_chain_getparent(parentp, how_maybe);
1729                 goto again;
1730         }
1731
1732         /*
1733          * Selected from blockref or in-memory chain.
1734          */
1735         if (chain == NULL) {
1736                 bcopy = *bref;
1737                 spin_unlock(&parent->core.cst.spin);
1738                 chain = hammer2_chain_get(parent, generation,
1739                                           &bcopy);
1740                 if (chain == NULL) {
1741                         kprintf("retry lookup parent %p keys %016jx:%016jx\n",
1742                                 parent, key_beg, key_end);
1743                         goto again;
1744                 }
1745                 if (bcmp(&bcopy, bref, sizeof(bcopy))) {
1746                         hammer2_chain_drop(chain);
1747                         goto again;
1748                 }
1749         } else {
1750                 hammer2_chain_ref(chain);
1751                 spin_unlock(&parent->core.cst.spin);
1752         }
1753
1754         /*
1755          * chain is referenced but not locked.  We must lock the chain
1756          * to obtain definitive DUPLICATED/DELETED state
1757          */
1758         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1759             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
1760                 hammer2_chain_lock(chain, how_maybe | HAMMER2_RESOLVE_NOREF);
1761         } else {
1762                 hammer2_chain_lock(chain, how | HAMMER2_RESOLVE_NOREF);
1763         }
1764
1765         /*
1766          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
1767          *
1768          * NOTE: Chain's key range is not relevant as there might be
1769          *       one-offs within the range that are not deleted.
1770          *
1771          * NOTE: Lookups can race delete-duplicate because
1772          *       delete-duplicate does not lock the parent's core
1773          *       (they just use the spinlock on the core).  We must
1774          *       check for races by comparing the DUPLICATED flag before
1775          *       releasing the spinlock with the flag after locking the
1776          *       chain.
1777          */
1778         if (chain->flags & HAMMER2_CHAIN_DELETED) {
1779                 hammer2_chain_unlock(chain);
1780                 key_beg = *key_nextp;
1781                 if (key_beg == 0 || key_beg > key_end)
1782                         return(NULL);
1783                 goto again;
1784         }
1785
1786         /*
1787          * If the chain element is an indirect block it becomes the new
1788          * parent and we loop on it.  We must maintain our top-down locks
1789          * to prevent the flusher from interfering (i.e. doing a
1790          * delete-duplicate and leaving us recursing down a deleted chain).
1791          *
1792          * The parent always has to be locked with at least RESOLVE_MAYBE
1793          * so we can access its data.  It might need a fixup if the caller
1794          * passed incompatible flags.  Be careful not to cause a deadlock
1795          * as a data-load requires an exclusive lock.
1796          *
1797          * If HAMMER2_LOOKUP_MATCHIND is set and the indirect block's key
1798          * range is within the requested key range we return the indirect
1799          * block and do NOT loop.  This is usually only used to acquire
1800          * freemap nodes.
1801          */
1802         if (chain->bref.type == HAMMER2_BREF_TYPE_INDIRECT ||
1803             chain->bref.type == HAMMER2_BREF_TYPE_FREEMAP_NODE) {
1804                 hammer2_chain_unlock(parent);
1805                 *parentp = parent = chain;
1806                 goto again;
1807         }
1808 done:
1809         /*
1810          * All done, return the chain
1811          */
1812         return (chain);
1813 }
1814
1815 /*
1816  * After having issued a lookup we can iterate all matching keys.
1817  *
1818  * If chain is non-NULL we continue the iteration from just after it's index.
1819  *
1820  * If chain is NULL we assume the parent was exhausted and continue the
1821  * iteration at the next parent.
1822  *
1823  * parent must be locked on entry and remains locked throughout.  chain's
1824  * lock status must match flags.  Chain is always at least referenced.
1825  *
1826  * WARNING!  The MATCHIND flag does not apply to this function.
1827  */
1828 hammer2_chain_t *
1829 hammer2_chain_next(hammer2_chain_t **parentp, hammer2_chain_t *chain,
1830                    hammer2_key_t *key_nextp,
1831                    hammer2_key_t key_beg, hammer2_key_t key_end,
1832                    int *cache_indexp, int flags)
1833 {
1834         hammer2_chain_t *parent;
1835         int how_maybe;
1836         int ddflag;
1837
1838         /*
1839          * Calculate locking flags for upward recursion.
1840          */
1841         how_maybe = HAMMER2_RESOLVE_MAYBE;
1842         if (flags & (HAMMER2_LOOKUP_SHARED | HAMMER2_LOOKUP_NOLOCK))
1843                 how_maybe |= HAMMER2_RESOLVE_SHARED;
1844
1845         parent = *parentp;
1846
1847         /*
1848          * Calculate the next index and recalculate the parent if necessary.
1849          */
1850         if (chain) {
1851                 key_beg = chain->bref.key +
1852                           ((hammer2_key_t)1 << chain->bref.keybits);
1853                 if (flags & HAMMER2_LOOKUP_NOLOCK)
1854                         hammer2_chain_drop(chain);
1855                 else
1856                         hammer2_chain_unlock(chain);
1857
1858                 /*
1859                  * Any scan where the lookup returned degenerate data embedded
1860                  * in the inode has an invalid index and must terminate.
1861                  */
1862                 if (chain == parent)
1863                         return(NULL);
1864                 if (key_beg == 0 || key_beg > key_end)
1865                         return(NULL);
1866                 chain = NULL;
1867         } else if (parent->bref.type != HAMMER2_BREF_TYPE_INDIRECT &&
1868                    parent->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE) {
1869                 /*
1870                  * We reached the end of the iteration.
1871                  */
1872                 return (NULL);
1873         } else {
1874                 /*
1875                  * Continue iteration with next parent unless the current
1876                  * parent covers the range.
1877                  */
1878                 key_beg = parent->bref.key +
1879                           ((hammer2_key_t)1 << parent->bref.keybits);
1880                 if (key_beg == 0 || key_beg > key_end)
1881                         return (NULL);
1882                 parent = hammer2_chain_getparent(parentp, how_maybe);
1883         }
1884
1885         /*
1886          * And execute
1887          */
1888         return (hammer2_chain_lookup(parentp, key_nextp,
1889                                      key_beg, key_end,
1890                                      cache_indexp, flags, &ddflag));
1891 }
1892
1893 /*
1894  * The raw scan function is similar to lookup/next but does not seek to a key.
1895  * Blockrefs are iterated via first_chain = (parent, NULL) and
1896  * next_chain = (parent, chain).
1897  *
1898  * The passed-in parent must be locked and its data resolved.  The returned
1899  * chain will be locked.  Pass chain == NULL to acquire the first sub-chain
1900  * under parent and then iterate with the passed-in chain (which this
1901  * function will unlock).
1902  */
1903 hammer2_chain_t *
1904 hammer2_chain_scan(hammer2_chain_t *parent, hammer2_chain_t *chain,
1905                    int *cache_indexp, int flags)
1906 {
1907         hammer2_mount_t *hmp;
1908         hammer2_blockref_t *base;
1909         hammer2_blockref_t *bref;
1910         hammer2_blockref_t bcopy;
1911         hammer2_key_t key;
1912         hammer2_key_t next_key;
1913         int count = 0;
1914         int how_always = HAMMER2_RESOLVE_ALWAYS;
1915         int how_maybe = HAMMER2_RESOLVE_MAYBE;
1916         int how;
1917         int generation;
1918         int maxloops = 300000;
1919
1920         hmp = parent->hmp;
1921
1922         /*
1923          * Scan flags borrowed from lookup
1924          */
1925         if (flags & HAMMER2_LOOKUP_ALWAYS) {
1926                 how_maybe = how_always;
1927                 how = HAMMER2_RESOLVE_ALWAYS;
1928         } else if (flags & (HAMMER2_LOOKUP_NODATA | HAMMER2_LOOKUP_NOLOCK)) {
1929                 how = HAMMER2_RESOLVE_NEVER;
1930         } else {
1931                 how = HAMMER2_RESOLVE_MAYBE;
1932         }
1933         if (flags & (HAMMER2_LOOKUP_SHARED | HAMMER2_LOOKUP_NOLOCK)) {
1934                 how_maybe |= HAMMER2_RESOLVE_SHARED;
1935                 how_always |= HAMMER2_RESOLVE_SHARED;
1936                 how |= HAMMER2_RESOLVE_SHARED;
1937         }
1938
1939         /*
1940          * Calculate key to locate first/next element, unlocking the previous
1941          * element as we go.  Be careful, the key calculation can overflow.
1942          */
1943         if (chain) {
1944                 key = chain->bref.key +
1945                       ((hammer2_key_t)1 << chain->bref.keybits);
1946                 hammer2_chain_unlock(chain);
1947                 chain = NULL;
1948                 if (key == 0)
1949                         goto done;
1950         } else {
1951                 key = 0;
1952         }
1953
1954 again:
1955         if (--maxloops == 0)
1956                 panic("hammer2_chain_scan: maxloops");
1957         /*
1958          * Locate the blockref array.  Currently we do a fully associative
1959          * search through the array.
1960          */
1961         switch(parent->bref.type) {
1962         case HAMMER2_BREF_TYPE_INODE:
1963                 /*
1964                  * An inode with embedded data has no sub-chains.
1965                  */
1966                 if (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA)
1967                         goto done;
1968                 base = &parent->data->ipdata.u.blockset.blockref[0];
1969                 count = HAMMER2_SET_COUNT;
1970                 break;
1971         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1972         case HAMMER2_BREF_TYPE_INDIRECT:
1973                 /*
1974                  * Optimize indirect blocks in the INITIAL state to avoid
1975                  * I/O.
1976                  */
1977                 if (parent->flags & HAMMER2_CHAIN_INITIAL) {
1978                         base = NULL;
1979                 } else {
1980                         if (parent->data == NULL)
1981                                 panic("parent->data is NULL");
1982                         base = &parent->data->npdata[0];
1983                 }
1984                 count = parent->bytes / sizeof(hammer2_blockref_t);
1985                 break;
1986         case HAMMER2_BREF_TYPE_VOLUME:
1987                 base = &hmp->voldata.sroot_blockset.blockref[0];
1988                 count = HAMMER2_SET_COUNT;
1989                 break;
1990         case HAMMER2_BREF_TYPE_FREEMAP:
1991                 base = &hmp->voldata.freemap_blockset.blockref[0];
1992                 count = HAMMER2_SET_COUNT;
1993                 break;
1994         default:
1995                 panic("hammer2_chain_lookup: unrecognized blockref type: %d",
1996                       parent->bref.type);
1997                 base = NULL;    /* safety */
1998                 count = 0;      /* safety */
1999         }
2000
2001         /*
2002          * Merged scan to find next candidate.
2003          *
2004          * hammer2_base_*() functions require the parent->core.live_* fields
2005          * to be synchronized.
2006          *
2007          * We need to hold the spinlock to access the block array and RB tree
2008          * and to interlock chain creation.
2009          */
2010         if ((parent->core.flags & HAMMER2_CORE_COUNTEDBREFS) == 0)
2011                 hammer2_chain_countbrefs(parent, base, count);
2012
2013         next_key = 0;
2014         spin_lock(&parent->core.cst.spin);
2015         chain = hammer2_combined_find(parent, base, count,
2016                                       cache_indexp, &next_key,
2017                                       key, HAMMER2_KEY_MAX,
2018                                       &bref);
2019         generation = parent->core.generation;
2020
2021         /*
2022          * Exhausted parent chain, we're done.
2023          */
2024         if (bref == NULL) {
2025                 spin_unlock(&parent->core.cst.spin);
2026                 KKASSERT(chain == NULL);
2027                 goto done;
2028         }
2029
2030         /*
2031          * Selected from blockref or in-memory chain.
2032          */
2033         if (chain == NULL) {
2034                 bcopy = *bref;
2035                 spin_unlock(&parent->core.cst.spin);
2036                 chain = hammer2_chain_get(parent, generation, &bcopy);
2037                 if (chain == NULL) {
2038                         kprintf("retry scan parent %p keys %016jx\n",
2039                                 parent, key);
2040                         goto again;
2041                 }
2042                 if (bcmp(&bcopy, bref, sizeof(bcopy))) {
2043                         hammer2_chain_drop(chain);
2044                         chain = NULL;
2045                         goto again;
2046                 }
2047         } else {
2048                 hammer2_chain_ref(chain);
2049                 spin_unlock(&parent->core.cst.spin);
2050         }
2051
2052         /*
2053          * chain is referenced but not locked.  We must lock the chain
2054          * to obtain definitive DUPLICATED/DELETED state
2055          */
2056         hammer2_chain_lock(chain, how | HAMMER2_RESOLVE_NOREF);
2057
2058         /*
2059          * Skip deleted chains (XXX cache 'i' end-of-block-array? XXX)
2060          *
2061          * NOTE: chain's key range is not relevant as there might be
2062          *       one-offs within the range that are not deleted.
2063          *
2064          * NOTE: XXX this could create problems with scans used in
2065          *       situations other than mount-time recovery.
2066          *
2067          * NOTE: Lookups can race delete-duplicate because
2068          *       delete-duplicate does not lock the parent's core
2069          *       (they just use the spinlock on the core).  We must
2070          *       check for races by comparing the DUPLICATED flag before
2071          *       releasing the spinlock with the flag after locking the
2072          *       chain.
2073          */
2074         if (chain->flags & HAMMER2_CHAIN_DELETED) {
2075                 hammer2_chain_unlock(chain);
2076                 chain = NULL;
2077
2078                 key = next_key;
2079                 if (key == 0)
2080                         goto done;
2081                 goto again;
2082         }
2083
2084 done:
2085         /*
2086          * All done, return the chain or NULL
2087          */
2088         return (chain);
2089 }
2090
2091 /*
2092  * Create and return a new hammer2 system memory structure of the specified
2093  * key, type and size and insert it under (*parentp).  This is a full
2094  * insertion, based on the supplied key/keybits, and may involve creating
2095  * indirect blocks and moving other chains around via delete/duplicate.
2096  *
2097  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (*parentp) TO THE INSERTION
2098  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
2099  * FULL.  This typically means that the caller is creating the chain after
2100  * doing a hammer2_chain_lookup().
2101  *
2102  * (*parentp) must be exclusive locked and may be replaced on return
2103  * depending on how much work the function had to do.
2104  *
2105  * (*chainp) usually starts out NULL and returns the newly created chain,
2106  * but if the caller desires the caller may allocate a disconnected chain
2107  * and pass it in instead.
2108  *
2109  * This function should NOT be used to insert INDIRECT blocks.  It is
2110  * typically used to create/insert inodes and data blocks.
2111  *
2112  * Caller must pass-in an exclusively locked parent the new chain is to
2113  * be inserted under, and optionally pass-in a disconnected, exclusively
2114  * locked chain to insert (else we create a new chain).  The function will
2115  * adjust (*parentp) as necessary, create or connect the chain, and
2116  * return an exclusively locked chain in *chainp.
2117  */
2118 int
2119 hammer2_chain_create(hammer2_trans_t *trans, hammer2_chain_t **parentp,
2120                      hammer2_chain_t **chainp, hammer2_pfsmount_t *pmp,
2121                      hammer2_key_t key, int keybits, int type, size_t bytes,
2122                      int flags)
2123 {
2124         hammer2_mount_t *hmp;
2125         hammer2_chain_t *chain;
2126         hammer2_chain_t *parent;
2127         hammer2_blockref_t *base;
2128         hammer2_blockref_t dummy;
2129         int allocated = 0;
2130         int error = 0;
2131         int count;
2132         int maxloops = 300000;
2133
2134         /*
2135          * Topology may be crossing a PFS boundary.
2136          */
2137         parent = *parentp;
2138         KKASSERT(ccms_thread_lock_owned(&parent->core.cst));
2139         hmp = parent->hmp;
2140         chain = *chainp;
2141
2142         if (chain == NULL) {
2143                 /*
2144                  * First allocate media space and construct the dummy bref,
2145                  * then allocate the in-memory chain structure.  Set the
2146                  * INITIAL flag for fresh chains which do not have embedded
2147                  * data.
2148                  */
2149                 bzero(&dummy, sizeof(dummy));
2150                 dummy.type = type;
2151                 dummy.key = key;
2152                 dummy.keybits = keybits;
2153                 dummy.data_off = hammer2_getradix(bytes);
2154                 dummy.methods = parent->bref.methods;
2155                 chain = hammer2_chain_alloc(hmp, pmp, trans, &dummy);
2156                 hammer2_chain_core_alloc(trans, chain);
2157
2158                 /*
2159                  * Lock the chain manually, chain_lock will load the chain
2160                  * which we do NOT want to do.  (note: chain->refs is set
2161                  * to 1 by chain_alloc() for us, but lockcnt is not).
2162                  */
2163                 chain->lockcnt = 1;
2164                 ccms_thread_lock(&chain->core.cst, CCMS_STATE_EXCLUSIVE);
2165                 allocated = 1;
2166
2167                 /*
2168                  * We do NOT set INITIAL here (yet).  INITIAL is only
2169                  * used for indirect blocks.
2170                  *
2171                  * Recalculate bytes to reflect the actual media block
2172                  * allocation.
2173                  */
2174                 bytes = (hammer2_off_t)1 <<
2175                         (int)(chain->bref.data_off & HAMMER2_OFF_MASK_RADIX);
2176                 chain->bytes = bytes;
2177
2178                 switch(type) {
2179                 case HAMMER2_BREF_TYPE_VOLUME:
2180                 case HAMMER2_BREF_TYPE_FREEMAP:
2181                         panic("hammer2_chain_create: called with volume type");
2182                         break;
2183                 case HAMMER2_BREF_TYPE_INDIRECT:
2184                         panic("hammer2_chain_create: cannot be used to"
2185                               "create indirect block");
2186                         break;
2187                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2188                         panic("hammer2_chain_create: cannot be used to"
2189                               "create freemap root or node");
2190                         break;
2191                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2192                         KKASSERT(bytes == sizeof(chain->data->bmdata));
2193                         /* fall through */
2194                 case HAMMER2_BREF_TYPE_INODE:
2195                 case HAMMER2_BREF_TYPE_DATA:
2196                 default:
2197                         /*
2198                          * leave chain->data NULL, set INITIAL
2199                          */
2200                         KKASSERT(chain->data == NULL);
2201                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
2202                         break;
2203                 }
2204
2205                 /*
2206                  * Set statistics for pending updates.  These will be
2207                  * synchronized by the flush code.
2208                  */
2209                 switch(type) {
2210                 case HAMMER2_BREF_TYPE_INODE:
2211                         chain->inode_count = 1;
2212                         break;
2213                 case HAMMER2_BREF_TYPE_DATA:
2214                 case HAMMER2_BREF_TYPE_INDIRECT:
2215                         chain->data_count = chain->bytes;
2216                         break;
2217                 }
2218         } else {
2219                 /*
2220                  * We are reattaching a previously deleted chain, possibly
2221                  * under a new parent and possibly with a new key/keybits.
2222                  * The chain does not have to be in a modified state.  The
2223                  * UPDATE flag will be set later on in this routine.
2224                  *
2225                  * Do NOT mess with the current state of the INITIAL flag.
2226                  */
2227                 chain->bref.key = key;
2228                 chain->bref.keybits = keybits;
2229                 if (chain->flags & HAMMER2_CHAIN_DELETED)
2230                         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_DELETED);
2231                 KKASSERT(chain->parent == NULL);
2232         }
2233
2234         /*
2235          * Calculate how many entries we have in the blockref array and
2236          * determine if an indirect block is required.
2237          */
2238 again:
2239         if (--maxloops == 0)
2240                 panic("hammer2_chain_create: maxloops");
2241
2242         switch(parent->bref.type) {
2243         case HAMMER2_BREF_TYPE_INODE:
2244                 KKASSERT((parent->data->ipdata.op_flags &
2245                           HAMMER2_OPFLAG_DIRECTDATA) == 0);
2246                 KKASSERT(parent->data != NULL);
2247                 base = &parent->data->ipdata.u.blockset.blockref[0];
2248                 count = HAMMER2_SET_COUNT;
2249                 break;
2250         case HAMMER2_BREF_TYPE_INDIRECT:
2251         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2252                 if (parent->flags & HAMMER2_CHAIN_INITIAL)
2253                         base = NULL;
2254                 else
2255                         base = &parent->data->npdata[0];
2256                 count = parent->bytes / sizeof(hammer2_blockref_t);
2257                 break;
2258         case HAMMER2_BREF_TYPE_VOLUME:
2259                 KKASSERT(parent->data != NULL);
2260                 base = &hmp->voldata.sroot_blockset.blockref[0];
2261                 count = HAMMER2_SET_COUNT;
2262                 break;
2263         case HAMMER2_BREF_TYPE_FREEMAP:
2264                 KKASSERT(parent->data != NULL);
2265                 base = &hmp->voldata.freemap_blockset.blockref[0];
2266                 count = HAMMER2_SET_COUNT;
2267                 break;
2268         default:
2269                 panic("hammer2_chain_create: unrecognized blockref type: %d",
2270                       parent->bref.type);
2271                 base = NULL;
2272                 count = 0;
2273                 break;
2274         }
2275
2276         /*
2277          * Make sure we've counted the brefs
2278          */
2279         if ((parent->core.flags & HAMMER2_CORE_COUNTEDBREFS) == 0)
2280                 hammer2_chain_countbrefs(parent, base, count);
2281
2282         KKASSERT(parent->core.live_count >= 0 &&
2283                  parent->core.live_count <= count);
2284
2285         /*
2286          * If no free blockref could be found we must create an indirect
2287          * block and move a number of blockrefs into it.  With the parent
2288          * locked we can safely lock each child in order to delete+duplicate
2289          * it without causing a deadlock.
2290          *
2291          * This may return the new indirect block or the old parent depending
2292          * on where the key falls.  NULL is returned on error.
2293          */
2294         if (parent->core.live_count == count) {
2295                 hammer2_chain_t *nparent;
2296
2297                 nparent = hammer2_chain_create_indirect(trans, parent,
2298                                                         key, keybits,
2299                                                         type, &error);
2300                 if (nparent == NULL) {
2301                         if (allocated)
2302                                 hammer2_chain_drop(chain);
2303                         chain = NULL;
2304                         goto done;
2305                 }
2306                 if (parent != nparent) {
2307                         hammer2_chain_unlock(parent);
2308                         parent = *parentp = nparent;
2309                 }
2310                 goto again;
2311         }
2312
2313         /*
2314          * Link the chain into its parent.
2315          */
2316         if (chain->parent != NULL)
2317                 panic("hammer2: hammer2_chain_create: chain already connected");
2318         KKASSERT(chain->parent == NULL);
2319         hammer2_chain_insert(parent, chain,
2320                              HAMMER2_CHAIN_INSERT_SPIN |
2321                              HAMMER2_CHAIN_INSERT_LIVE,
2322                              0);
2323
2324         if (allocated) {
2325                 /*
2326                  * Mark the newly created chain modified.  This will cause
2327                  * UPDATE to be set.
2328                  *
2329                  * Device buffers are not instantiated for DATA elements
2330                  * as these are handled by logical buffers.
2331                  *
2332                  * Indirect and freemap node indirect blocks are handled
2333                  * by hammer2_chain_create_indirect() and not by this
2334                  * function.
2335                  *
2336                  * Data for all other bref types is expected to be
2337                  * instantiated (INODE, LEAF).
2338                  */
2339                 switch(chain->bref.type) {
2340                 case HAMMER2_BREF_TYPE_DATA:
2341                 case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2342                 case HAMMER2_BREF_TYPE_INODE:
2343                         hammer2_chain_modify(trans, chain,
2344                                              HAMMER2_MODIFY_OPTDATA);
2345                         break;
2346                 default:
2347                         /*
2348                          * Remaining types are not supported by this function.
2349                          * In particular, INDIRECT and LEAF_NODE types are
2350                          * handled by create_indirect().
2351                          */
2352                         panic("hammer2_chain_create: bad type: %d",
2353                               chain->bref.type);
2354                         /* NOT REACHED */
2355                         break;
2356                 }
2357         } else {
2358                 /*
2359                  * When reconnecting a chain we must set UPDATE and
2360                  * setflush so the flush recognizes that it must update
2361                  * the bref in the parent.
2362                  */
2363                 if ((chain->flags & HAMMER2_CHAIN_UPDATE) == 0) {
2364                         hammer2_chain_ref(chain);
2365                         atomic_set_int(&chain->flags, HAMMER2_CHAIN_UPDATE);
2366                 }
2367                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2368                     (flags & HAMMER2_INSERT_NOSTATS) == 0) {
2369                         KKASSERT(chain->data);
2370                         chain->inode_count_up +=
2371                                 chain->data->ipdata.inode_count;
2372                         chain->data_count_up +=
2373                                 chain->data->ipdata.data_count;
2374                 }
2375         }
2376
2377         /*
2378          * We must setflush(parent) to ensure that it recurses through to
2379          * chain.  setflush(chain) might not work because ONFLUSH is possibly
2380          * already set in the chain (so it won't recurse up to set it in the
2381          * parent).
2382          */
2383         hammer2_chain_setflush(trans, parent);
2384
2385 done:
2386         *chainp = chain;
2387
2388         return (error);
2389 }
2390
2391 /*
2392  * Move the chain from its old parent to a new parent.  The chain must have
2393  * already been deleted or already disconnected (or never associated) with
2394  * a parent.  The chain is reassociated with the new parent and the deleted
2395  * flag will be cleared (no longer deleted).  The chain's modification state
2396  * is not altered.
2397  *
2398  * THE CALLER MUST HAVE ALREADY PROPERLY SEEKED (parent) TO THE INSERTION
2399  * POINT SANS ANY REQUIRED INDIRECT BLOCK CREATIONS DUE TO THE ARRAY BEING
2400  * FULL.  This typically means that the caller is creating the chain after
2401  * doing a hammer2_chain_lookup().
2402  *
2403  * A non-NULL bref is typically passed when key and keybits must be overridden.
2404  * Note that hammer2_cluster_duplicate() *ONLY* uses the key and keybits fields
2405  * from a passed-in bref and uses the old chain's bref for everything else.
2406  *
2407  * If (parent) is non-NULL then the new duplicated chain is inserted under
2408  * the parent.
2409  *
2410  * If (parent) is NULL then the newly duplicated chain is not inserted
2411  * anywhere, similar to if it had just been chain_alloc()'d (suitable for
2412  * passing into hammer2_chain_create() after this function returns).
2413  *
2414  * WARNING! This function calls create which means it can insert indirect
2415  *          blocks.  This can cause other unrelated chains in the parent to
2416  *          be moved to a newly inserted indirect block in addition to the
2417  *          specific chain.
2418  */
2419 void
2420 hammer2_chain_rename(hammer2_trans_t *trans, hammer2_blockref_t *bref,
2421                      hammer2_chain_t **parentp, hammer2_chain_t *chain,
2422                      int flags)
2423 {
2424         hammer2_mount_t *hmp;
2425         hammer2_chain_t *parent;
2426         size_t bytes;
2427
2428         /*
2429          * WARNING!  We should never resolve DATA to device buffers
2430          *           (XXX allow it if the caller did?), and since
2431          *           we currently do not have the logical buffer cache
2432          *           buffer in-hand to fix its cached physical offset
2433          *           we also force the modify code to not COW it. XXX
2434          */
2435         hmp = chain->hmp;
2436         KKASSERT(chain->parent == NULL);
2437
2438         /*
2439          * Now create a duplicate of the chain structure, associating
2440          * it with the same core, making it the same size, pointing it
2441          * to the same bref (the same media block).
2442          */
2443         if (bref == NULL)
2444                 bref = &chain->bref;
2445         bytes = (hammer2_off_t)1 <<
2446                 (int)(bref->data_off & HAMMER2_OFF_MASK_RADIX);
2447
2448         /*
2449          * If parent is not NULL the duplicated chain will be entered under
2450          * the parent and the UPDATE bit set to tell flush to update
2451          * the blockref.
2452          *
2453          * We must setflush(parent) to ensure that it recurses through to
2454          * chain.  setflush(chain) might not work because ONFLUSH is possibly
2455          * already set in the chain (so it won't recurse up to set it in the
2456          * parent).
2457          *
2458          * Having both chains locked is extremely important for atomicy.
2459          */
2460         if (parentp && (parent = *parentp) != NULL) {
2461                 KKASSERT(ccms_thread_lock_owned(&parent->core.cst));
2462                 KKASSERT(parent->refs > 0);
2463
2464                 hammer2_chain_create(trans, parentp, &chain, chain->pmp,
2465                                      bref->key, bref->keybits, bref->type,
2466                                      chain->bytes, flags);
2467                 KKASSERT(chain->flags & HAMMER2_CHAIN_UPDATE);
2468                 hammer2_chain_setflush(trans, *parentp);
2469         }
2470 }
2471
2472 /*
2473  * Helper function for deleting chains.
2474  *
2475  * The chain is removed from the live view (the RBTREE) as well as the parent's
2476  * blockmap.  Both chain and its parent must be locked.
2477  */
2478 static void
2479 _hammer2_chain_delete_helper(hammer2_trans_t *trans,
2480                              hammer2_chain_t *parent, hammer2_chain_t *chain,
2481                              int flags)
2482 {
2483         hammer2_mount_t *hmp;
2484
2485         KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0);
2486         hmp = chain->hmp;
2487
2488         if (chain->flags & HAMMER2_CHAIN_BMAPPED) {
2489                 /*
2490                  * Chain is blockmapped, so there must be a parent.
2491                  * Atomically remove the chain from the parent and remove
2492                  * the blockmap entry.
2493                  */
2494                 hammer2_blockref_t *base;
2495                 int count;
2496
2497                 KKASSERT(parent != NULL);
2498                 KKASSERT((parent->flags & HAMMER2_CHAIN_INITIAL) == 0);
2499                 hammer2_chain_modify(trans, parent,
2500                                      HAMMER2_MODIFY_OPTDATA);
2501
2502                 /*
2503                  * Calculate blockmap pointer
2504                  */
2505                 KKASSERT(chain->flags & HAMMER2_CHAIN_ONRBTREE);
2506                 spin_lock(&parent->core.cst.spin);
2507
2508                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
2509                 atomic_add_int(&parent->core.live_count, -1);
2510                 ++parent->core.generation;
2511                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
2512                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
2513                 --parent->core.chain_count;
2514                 chain->parent = NULL;
2515
2516                 switch(parent->bref.type) {
2517                 case HAMMER2_BREF_TYPE_INODE:
2518                         /*
2519                          * Access the inode's block array.  However, there
2520                          * is no block array if the inode is flagged
2521                          * DIRECTDATA.  The DIRECTDATA case typicaly only
2522                          * occurs when a hardlink has been shifted up the
2523                          * tree and the original inode gets replaced with
2524                          * an OBJTYPE_HARDLINK placeholding inode.
2525                          */
2526                         if (parent->data &&
2527                             (parent->data->ipdata.op_flags &
2528                              HAMMER2_OPFLAG_DIRECTDATA) == 0) {
2529                                 base =
2530                                    &parent->data->ipdata.u.blockset.blockref[0];
2531                         } else {
2532                                 base = NULL;
2533                         }
2534                         count = HAMMER2_SET_COUNT;
2535                         break;
2536                 case HAMMER2_BREF_TYPE_INDIRECT:
2537                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2538                         if (parent->data)
2539                                 base = &parent->data->npdata[0];
2540                         else
2541                                 base = NULL;
2542                         count = parent->bytes / sizeof(hammer2_blockref_t);
2543                         break;
2544                 case HAMMER2_BREF_TYPE_VOLUME:
2545                         base = &hmp->voldata.sroot_blockset.blockref[0];
2546                         count = HAMMER2_SET_COUNT;
2547                         break;
2548                 case HAMMER2_BREF_TYPE_FREEMAP:
2549                         base = &parent->data->npdata[0];
2550                         count = HAMMER2_SET_COUNT;
2551                         break;
2552                 default:
2553                         base = NULL;
2554                         count = 0;
2555                         panic("hammer2_flush_pass2: "
2556                               "unrecognized blockref type: %d",
2557                               parent->bref.type);
2558                 }
2559
2560                 /*
2561                  * delete blockmapped chain from its parent.
2562                  *
2563                  * The parent is not affected by any statistics in chain
2564                  * which are pending synchronization.  That is, there is
2565                  * nothing to undo in the parent since they have not yet
2566                  * been incorporated into the parent.
2567                  *
2568                  * The parent is affected by statistics stored in inodes.
2569                  * Those have already been synchronized, so they must be
2570                  * undone.  XXX split update possible w/delete in middle?
2571                  */
2572                 if (base) {
2573                         if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2574                             (flags & HAMMER2_DELETE_NOSTATS) == 0) {
2575                                 KKASSERT(chain->data != NULL);
2576                                 parent->data_count -=
2577                                         chain->data->ipdata.data_count;
2578                                 parent->inode_count -=
2579                                         chain->data->ipdata.inode_count;
2580                         }
2581
2582                         int cache_index = -1;
2583                         hammer2_base_delete(trans, parent, base, count,
2584                                             &cache_index, chain);
2585                 }
2586                 spin_unlock(&parent->core.cst.spin);
2587         } else if (chain->flags & HAMMER2_CHAIN_ONRBTREE) {
2588                 /*
2589                  * Chain is not blockmapped but a parent is present.
2590                  * Atomically remove the chain from the parent.  There is
2591                  * no blockmap entry to remove.
2592                  *
2593                  * Because chain was associated with a parent but not
2594                  * synchronized, the chain's *_count_up fields contain
2595                  * inode adjustment statistics which must be undone.
2596                  */
2597                 spin_lock(&parent->core.cst.spin);
2598                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2599                     (flags & HAMMER2_DELETE_NOSTATS) == 0) {
2600                         KKASSERT(chain->data != NULL);
2601                         chain->data_count_up -=
2602                                 chain->data->ipdata.data_count;
2603                         chain->inode_count_up -=
2604                                 chain->data->ipdata.inode_count;
2605                 }
2606                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
2607                 atomic_add_int(&parent->core.live_count, -1);
2608                 ++parent->core.generation;
2609                 RB_REMOVE(hammer2_chain_tree, &parent->core.rbtree, chain);
2610                 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONRBTREE);
2611                 --parent->core.chain_count;
2612                 chain->parent = NULL;
2613                 spin_unlock(&parent->core.cst.spin);
2614         } else {
2615                 /*
2616                  * Chain is not blockmapped and has no parent.  This
2617                  * is a degenerate case.
2618                  */
2619                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DELETED);
2620         }
2621
2622         /*
2623          * If the deletion is permanent (i.e. the chain is not simply being
2624          * moved within the topology), adjust the freemap to indicate that
2625          * the block *might* be freeable.  bulkfree must still determine
2626          * that it is actually freeable.
2627          */
2628         if ((flags & HAMMER2_DELETE_PERMANENT) &&
2629             chain->bref.type != HAMMER2_BREF_TYPE_FREEMAP_NODE &&
2630             chain->bref.type != HAMMER2_BREF_TYPE_FREEMAP_LEAF &&
2631             (chain->bref.data_off & ~HAMMER2_OFF_MASK_RADIX)) {
2632                 hammer2_freemap_adjust(trans, hmp, &chain->bref,
2633                                        HAMMER2_FREEMAP_DOMAYFREE);
2634         }
2635 }
2636
2637 /*
2638  * Create an indirect block that covers one or more of the elements in the
2639  * current parent.  Either returns the existing parent with no locking or
2640  * ref changes or returns the new indirect block locked and referenced
2641  * and leaving the original parent lock/ref intact as well.
2642  *
2643  * If an error occurs, NULL is returned and *errorp is set to the error.
2644  *
2645  * The returned chain depends on where the specified key falls.
2646  *
2647  * The key/keybits for the indirect mode only needs to follow three rules:
2648  *
2649  * (1) That all elements underneath it fit within its key space and
2650  *
2651  * (2) That all elements outside it are outside its key space.
2652  *
2653  * (3) When creating the new indirect block any elements in the current
2654  *     parent that fit within the new indirect block's keyspace must be
2655  *     moved into the new indirect block.
2656  *
2657  * (4) The keyspace chosen for the inserted indirect block CAN cover a wider
2658  *     keyspace the the current parent, but lookup/iteration rules will
2659  *     ensure (and must ensure) that rule (2) for all parents leading up
2660  *     to the nearest inode or the root volume header is adhered to.  This
2661  *     is accomplished by always recursing through matching keyspaces in
2662  *     the hammer2_chain_lookup() and hammer2_chain_next() API.
2663  *
2664  * The current implementation calculates the current worst-case keyspace by
2665  * iterating the current parent and then divides it into two halves, choosing
2666  * whichever half has the most elements (not necessarily the half containing
2667  * the requested key).
2668  *
2669  * We can also opt to use the half with the least number of elements.  This
2670  * causes lower-numbered keys (aka logical file offsets) to recurse through
2671  * fewer indirect blocks and higher-numbered keys to recurse through more.
2672  * This also has the risk of not moving enough elements to the new indirect
2673  * block and being forced to create several indirect blocks before the element
2674  * can be inserted.
2675  *
2676  * Must be called with an exclusively locked parent.
2677  */
2678 static int hammer2_chain_indkey_freemap(hammer2_chain_t *parent,
2679                                 hammer2_key_t *keyp, int keybits,
2680                                 hammer2_blockref_t *base, int count);
2681 static int hammer2_chain_indkey_normal(hammer2_chain_t *parent,
2682                                 hammer2_key_t *keyp, int keybits,
2683                                 hammer2_blockref_t *base, int count);
2684 static
2685 hammer2_chain_t *
2686 hammer2_chain_create_indirect(hammer2_trans_t *trans, hammer2_chain_t *parent,
2687                               hammer2_key_t create_key, int create_bits,
2688                               int for_type, int *errorp)
2689 {
2690         hammer2_mount_t *hmp;
2691         hammer2_blockref_t *base;
2692         hammer2_blockref_t *bref;
2693         hammer2_blockref_t bcopy;
2694         hammer2_chain_t *chain;
2695         hammer2_chain_t *ichain;
2696         hammer2_chain_t dummy;
2697         hammer2_key_t key = create_key;
2698         hammer2_key_t key_beg;
2699         hammer2_key_t key_end;
2700         hammer2_key_t key_next;
2701         int keybits = create_bits;
2702         int count;
2703         int nbytes;
2704         int cache_index;
2705         int loops;
2706         int reason;
2707         int generation;
2708         int maxloops = 300000;
2709
2710         /*
2711          * Calculate the base blockref pointer or NULL if the chain
2712          * is known to be empty.  We need to calculate the array count
2713          * for RB lookups either way.
2714          */
2715         hmp = parent->hmp;
2716         *errorp = 0;
2717         KKASSERT(ccms_thread_lock_owned(&parent->core.cst));
2718
2719         /*hammer2_chain_modify(trans, &parent, HAMMER2_MODIFY_OPTDATA);*/
2720         if (parent->flags & HAMMER2_CHAIN_INITIAL) {
2721                 base = NULL;
2722
2723                 switch(parent->bref.type) {
2724                 case HAMMER2_BREF_TYPE_INODE:
2725                         count = HAMMER2_SET_COUNT;
2726                         break;
2727                 case HAMMER2_BREF_TYPE_INDIRECT:
2728                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2729                         count = parent->bytes / sizeof(hammer2_blockref_t);
2730                         break;
2731                 case HAMMER2_BREF_TYPE_VOLUME:
2732                         count = HAMMER2_SET_COUNT;
2733                         break;
2734                 case HAMMER2_BREF_TYPE_FREEMAP:
2735                         count = HAMMER2_SET_COUNT;
2736                         break;
2737                 default:
2738                         panic("hammer2_chain_create_indirect: "
2739                               "unrecognized blockref type: %d",
2740                               parent->bref.type);
2741                         count = 0;
2742                         break;
2743                 }
2744         } else {
2745                 switch(parent->bref.type) {
2746                 case HAMMER2_BREF_TYPE_INODE:
2747                         base = &parent->data->ipdata.u.blockset.blockref[0];
2748                         count = HAMMER2_SET_COUNT;
2749                         break;
2750                 case HAMMER2_BREF_TYPE_INDIRECT:
2751                 case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2752                         base = &parent->data->npdata[0];
2753                         count = parent->bytes / sizeof(hammer2_blockref_t);
2754                         break;
2755                 case HAMMER2_BREF_TYPE_VOLUME:
2756                         base = &hmp->voldata.sroot_blockset.blockref[0];
2757                         count = HAMMER2_SET_COUNT;
2758                         break;
2759                 case HAMMER2_BREF_TYPE_FREEMAP:
2760                         base = &hmp->voldata.freemap_blockset.blockref[0];
2761                         count = HAMMER2_SET_COUNT;
2762                         break;
2763                 default:
2764                         panic("hammer2_chain_create_indirect: "
2765                               "unrecognized blockref type: %d",
2766                               parent->bref.type);
2767                         count = 0;
2768                         break;
2769                 }
2770         }
2771
2772         /*
2773          * dummy used in later chain allocation (no longer used for lookups).
2774          */
2775         bzero(&dummy, sizeof(dummy));
2776
2777         /*
2778          * When creating an indirect block for a freemap node or leaf
2779          * the key/keybits must be fitted to static radix levels because
2780          * particular radix levels use particular reserved blocks in the
2781          * related zone.
2782          *
2783          * This routine calculates the key/radix of the indirect block
2784          * we need to create, and whether it is on the high-side or the
2785          * low-side.
2786          */
2787         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
2788             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
2789                 keybits = hammer2_chain_indkey_freemap(parent, &key, keybits,
2790                                                        base, count);
2791         } else {
2792                 keybits = hammer2_chain_indkey_normal(parent, &key, keybits,
2793                                                       base, count);
2794         }
2795
2796         /*
2797          * Normalize the key for the radix being represented, keeping the
2798          * high bits and throwing away the low bits.
2799          */
2800         key &= ~(((hammer2_key_t)1 << keybits) - 1);
2801
2802         /*
2803          * How big should our new indirect block be?  It has to be at least
2804          * as large as its parent.
2805          */
2806         if (parent->bref.type == HAMMER2_BREF_TYPE_INODE)
2807                 nbytes = HAMMER2_IND_BYTES_MIN;
2808         else
2809                 nbytes = HAMMER2_IND_BYTES_MAX;
2810         if (nbytes < count * sizeof(hammer2_blockref_t))
2811                 nbytes = count * sizeof(hammer2_blockref_t);
2812
2813         /*
2814          * Ok, create our new indirect block
2815          */
2816         if (for_type == HAMMER2_BREF_TYPE_FREEMAP_NODE ||
2817             for_type == HAMMER2_BREF_TYPE_FREEMAP_LEAF) {
2818                 dummy.bref.type = HAMMER2_BREF_TYPE_FREEMAP_NODE;
2819         } else {
2820                 dummy.bref.type = HAMMER2_BREF_TYPE_INDIRECT;
2821         }
2822         dummy.bref.key = key;
2823         dummy.bref.keybits = keybits;
2824         dummy.bref.data_off = hammer2_getradix(nbytes);
2825         dummy.bref.methods = parent->bref.methods;
2826
2827         ichain = hammer2_chain_alloc(hmp, parent->pmp, trans, &dummy.bref);
2828         atomic_set_int(&ichain->flags, HAMMER2_CHAIN_INITIAL);
2829         hammer2_chain_core_alloc(trans, ichain);
2830         hammer2_chain_lock(ichain, HAMMER2_RESOLVE_MAYBE);
2831         hammer2_chain_drop(ichain);     /* excess ref from alloc */
2832
2833         /*
2834          * We have to mark it modified to allocate its block, but use
2835          * OPTDATA to allow it to remain in the INITIAL state.  Otherwise
2836          * it won't be acted upon by the flush code.
2837          */
2838         hammer2_chain_modify(trans, ichain, HAMMER2_MODIFY_OPTDATA);
2839
2840         /*
2841          * Iterate the original parent and move the matching brefs into
2842          * the new indirect block.
2843          *
2844          * XXX handle flushes.
2845          */
2846         key_beg = 0;
2847         key_end = HAMMER2_KEY_MAX;
2848         cache_index = 0;
2849         spin_lock(&parent->core.cst.spin);
2850         loops = 0;
2851         reason = 0;
2852
2853         for (;;) {
2854                 if (++loops > 100000) {
2855                     spin_unlock(&parent->core.cst.spin);
2856                     panic("excessive loops r=%d p=%p base/count %p:%d %016jx\n",
2857                           reason, parent, base, count, key_next);
2858                 }
2859
2860                 /*
2861                  * NOTE: spinlock stays intact, returned chain (if not NULL)
2862                  *       is not referenced or locked which means that we
2863                  *       cannot safely check its flagged / deletion status
2864                  *       until we lock it.
2865                  */
2866                 chain = hammer2_combined_find(parent, base, count,
2867                                               &cache_index, &key_next,
2868                                               key_beg, key_end,
2869                                               &bref);
2870                 generation = parent->core.generation;
2871                 if (bref == NULL)
2872                         break;
2873                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
2874
2875                 /*
2876                  * Skip keys that are not within the key/radix of the new
2877                  * indirect block.  They stay in the parent.
2878                  */
2879                 if ((~(((hammer2_key_t)1 << keybits) - 1) &
2880                     (key ^ bref->key)) != 0) {
2881                         goto next_key_spinlocked;
2882                 }
2883
2884                 /*
2885                  * Load the new indirect block by acquiring the related
2886                  * chains (potentially from media as it might not be
2887                  * in-memory).  Then move it to the new parent (ichain)
2888                  * via DELETE-DUPLICATE.
2889                  *
2890                  * chain is referenced but not locked.  We must lock the
2891                  * chain to obtain definitive DUPLICATED/DELETED state
2892                  */
2893                 if (chain) {
2894                         /*
2895                          * Use chain already present in the RBTREE
2896                          */
2897                         hammer2_chain_ref(chain);
2898                         spin_unlock(&parent->core.cst.spin);
2899                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_NEVER |
2900                                                   HAMMER2_RESOLVE_NOREF);
2901                 } else {
2902                         /*
2903                          * Get chain for blockref element.  _get returns NULL
2904                          * on insertion race.
2905                          */
2906                         bcopy = *bref;
2907                         spin_unlock(&parent->core.cst.spin);
2908                         chain = hammer2_chain_get(parent, generation, &bcopy);
2909                         if (chain == NULL) {
2910                                 reason = 1;
2911                                 spin_lock(&parent->core.cst.spin);
2912                                 continue;
2913                         }
2914                         if (bcmp(&bcopy, bref, sizeof(bcopy))) {
2915                                 kprintf("REASON 2\n");
2916                                 reason = 2;
2917                                 hammer2_chain_drop(chain);
2918                                 spin_lock(&parent->core.cst.spin);
2919                                 continue;
2920                         }
2921                         hammer2_chain_lock(chain, HAMMER2_RESOLVE_NEVER |
2922                                                   HAMMER2_RESOLVE_NOREF);
2923                 }
2924
2925                 /*
2926                  * This is always live so if the chain has been deleted
2927                  * we raced someone and we have to retry.
2928                  *
2929                  * NOTE: Lookups can race delete-duplicate because
2930                  *       delete-duplicate does not lock the parent's core
2931                  *       (they just use the spinlock on the core).  We must
2932                  *       check for races by comparing the DUPLICATED flag before
2933                  *       releasing the spinlock with the flag after locking the
2934                  *       chain.
2935                  *
2936                  *       (note reversed logic for this one)
2937                  */
2938                 if (chain->flags & HAMMER2_CHAIN_DELETED) {
2939                         hammer2_chain_unlock(chain);
2940                         goto next_key;
2941                 }
2942
2943                 /*
2944                  * Shift the chain to the indirect block.
2945                  *
2946                  * WARNING! No reason for us to load chain data, pass NOSTATS
2947                  *          to prevent delete/insert from trying to access
2948                  *          inode stats (and thus asserting if there is no
2949                  *          chain->data loaded).
2950                  */
2951                 hammer2_chain_delete(trans, parent, chain,
2952                                      HAMMER2_DELETE_NOSTATS);
2953                 hammer2_chain_rename(trans, NULL, &ichain, chain,
2954                                      HAMMER2_INSERT_NOSTATS);
2955                 hammer2_chain_unlock(chain);
2956                 KKASSERT(parent->refs > 0);
2957                 chain = NULL;
2958 next_key:
2959                 spin_lock(&parent->core.cst.spin);
2960 next_key_spinlocked:
2961                 if (--maxloops == 0)
2962                         panic("hammer2_chain_create_indirect: maxloops");
2963                 reason = 4;
2964                 if (key_next == 0 || key_next > key_end)
2965                         break;
2966                 key_beg = key_next;
2967                 /* loop */
2968         }
2969         spin_unlock(&parent->core.cst.spin);
2970
2971         /*
2972          * Insert the new indirect block into the parent now that we've
2973          * cleared out some entries in the parent.  We calculated a good
2974          * insertion index in the loop above (ichain->index).
2975          *
2976          * We don't have to set UPDATE here because we mark ichain
2977          * modified down below (so the normal modified -> flush -> set-moved
2978          * sequence applies).
2979          *
2980          * The insertion shouldn't race as this is a completely new block
2981          * and the parent is locked.
2982          */
2983         KKASSERT((ichain->flags & HAMMER2_CHAIN_ONRBTREE) == 0);
2984         hammer2_chain_insert(parent, ichain,
2985                              HAMMER2_CHAIN_INSERT_SPIN |
2986                              HAMMER2_CHAIN_INSERT_LIVE,
2987                              0);
2988
2989         /*
2990          * Make sure flushes propogate after our manual insertion.
2991          */
2992         hammer2_chain_setflush(trans, ichain);
2993         hammer2_chain_setflush(trans, parent);
2994
2995         /*
2996          * Figure out what to return.
2997          */
2998         if (~(((hammer2_key_t)1 << keybits) - 1) &
2999                    (create_key ^ key)) {
3000                 /*
3001                  * Key being created is outside the key range,
3002                  * return the original parent.
3003                  */
3004                 hammer2_chain_unlock(ichain);
3005         } else {
3006                 /*
3007                  * Otherwise its in the range, return the new parent.
3008                  * (leave both the new and old parent locked).
3009                  */
3010                 parent = ichain;
3011         }
3012
3013         return(parent);
3014 }
3015
3016 /*
3017  * Calculate the keybits and highside/lowside of the freemap node the
3018  * caller is creating.
3019  *
3020  * This routine will specify the next higher-level freemap key/radix
3021  * representing the lowest-ordered set.  By doing so, eventually all
3022  * low-ordered sets will be moved one level down.
3023  *
3024  * We have to be careful here because the freemap reserves a limited
3025  * number of blocks for a limited number of levels.  So we can't just
3026  * push indiscriminately.
3027  */
3028 int
3029 hammer2_chain_indkey_freemap(hammer2_chain_t *parent, hammer2_key_t *keyp,
3030                              int keybits, hammer2_blockref_t *base, int count)
3031 {
3032         hammer2_chain_t *chain;
3033         hammer2_blockref_t *bref;
3034         hammer2_key_t key;
3035         hammer2_key_t key_beg;
3036         hammer2_key_t key_end;
3037         hammer2_key_t key_next;
3038         int cache_index;
3039         int locount;
3040         int hicount;
3041         int maxloops = 300000;
3042
3043         key = *keyp;
3044         locount = 0;
3045         hicount = 0;
3046         keybits = 64;
3047
3048         /*
3049          * Calculate the range of keys in the array being careful to skip
3050          * slots which are overridden with a deletion.
3051          */
3052         key_beg = 0;
3053         key_end = HAMMER2_KEY_MAX;
3054         cache_index = 0;
3055         spin_lock(&parent->core.cst.spin);
3056
3057         for (;;) {
3058                 if (--maxloops == 0) {
3059                         panic("indkey_freemap shit %p %p:%d\n",
3060                               parent, base, count);
3061                 }
3062                 chain = hammer2_combined_find(parent, base, count,
3063                                               &cache_index, &key_next,
3064                                               key_beg, key_end,
3065                                               &bref);
3066
3067                 /*
3068                  * Exhausted search
3069                  */
3070                 if (bref == NULL)
3071                         break;
3072
3073                 /*
3074                  * Skip deleted chains.
3075                  */
3076                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
3077                         if (key_next == 0 || key_next > key_end)
3078                                 break;
3079                         key_beg = key_next;
3080                         continue;
3081                 }
3082
3083                 /*
3084                  * Use the full live (not deleted) element for the scan
3085                  * iteration.  HAMMER2 does not allow partial replacements.
3086                  *
3087                  * XXX should be built into hammer2_combined_find().
3088                  */
3089                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
3090
3091                 if (keybits > bref->keybits) {
3092                         key = bref->key;
3093                         keybits = bref->keybits;
3094                 } else if (keybits == bref->keybits && bref->key < key) {
3095                         key = bref->key;
3096                 }
3097                 if (key_next == 0)
3098                         break;
3099                 key_beg = key_next;
3100         }
3101         spin_unlock(&parent->core.cst.spin);
3102
3103         /*
3104          * Return the keybits for a higher-level FREEMAP_NODE covering
3105          * this node.
3106          */
3107         switch(keybits) {
3108         case HAMMER2_FREEMAP_LEVEL0_RADIX:
3109                 keybits = HAMMER2_FREEMAP_LEVEL1_RADIX;
3110                 break;
3111         case HAMMER2_FREEMAP_LEVEL1_RADIX:
3112                 keybits = HAMMER2_FREEMAP_LEVEL2_RADIX;
3113                 break;
3114         case HAMMER2_FREEMAP_LEVEL2_RADIX:
3115                 keybits = HAMMER2_FREEMAP_LEVEL3_RADIX;
3116                 break;
3117         case HAMMER2_FREEMAP_LEVEL3_RADIX:
3118                 keybits = HAMMER2_FREEMAP_LEVEL4_RADIX;
3119                 break;
3120         case HAMMER2_FREEMAP_LEVEL4_RADIX:
3121                 panic("hammer2_chain_indkey_freemap: level too high");
3122                 break;
3123         default:
3124                 panic("hammer2_chain_indkey_freemap: bad radix");
3125                 break;
3126         }
3127         *keyp = key;
3128
3129         return (keybits);
3130 }
3131
3132 /*
3133  * Calculate the keybits and highside/lowside of the indirect block the
3134  * caller is creating.
3135  */
3136 static int
3137 hammer2_chain_indkey_normal(hammer2_chain_t *parent, hammer2_key_t *keyp,
3138                             int keybits, hammer2_blockref_t *base, int count)
3139 {
3140         hammer2_blockref_t *bref;
3141         hammer2_chain_t *chain;
3142         hammer2_key_t key_beg;
3143         hammer2_key_t key_end;
3144         hammer2_key_t key_next;
3145         hammer2_key_t key;
3146         int nkeybits;
3147         int locount;
3148         int hicount;
3149         int cache_index;
3150         int maxloops = 300000;
3151
3152         key = *keyp;
3153         locount = 0;
3154         hicount = 0;
3155
3156         /*
3157          * Calculate the range of keys in the array being careful to skip
3158          * slots which are overridden with a deletion.  Once the scan
3159          * completes we will cut the key range in half and shift half the
3160          * range into the new indirect block.
3161          */
3162         key_beg = 0;
3163         key_end = HAMMER2_KEY_MAX;
3164         cache_index = 0;
3165         spin_lock(&parent->core.cst.spin);
3166
3167         for (;;) {
3168                 if (--maxloops == 0) {
3169                         panic("indkey_freemap shit %p %p:%d\n",
3170                               parent, base, count);
3171                 }
3172                 chain = hammer2_combined_find(parent, base, count,
3173                                               &cache_index, &key_next,
3174                                               key_beg, key_end,
3175                                               &bref);
3176
3177                 /*
3178                  * Exhausted search
3179                  */
3180                 if (bref == NULL)
3181                         break;
3182
3183                 /*
3184                  * NOTE: No need to check DUPLICATED here because we do
3185                  *       not release the spinlock.
3186                  */
3187                 if (chain && (chain->flags & HAMMER2_CHAIN_DELETED)) {
3188                         if (key_next == 0 || key_next > key_end)
3189                                 break;
3190                         key_beg = key_next;
3191                         continue;
3192                 }
3193
3194                 /*
3195                  * Use the full live (not deleted) element for the scan
3196                  * iteration.  HAMMER2 does not allow partial replacements.
3197                  *
3198                  * XXX should be built into hammer2_combined_find().
3199                  */
3200                 key_next = bref->key + ((hammer2_key_t)1 << bref->keybits);
3201
3202                 /*
3203                  * Expand our calculated key range (key, keybits) to fit
3204                  * the scanned key.  nkeybits represents the full range
3205                  * that we will later cut in half (two halves @ nkeybits - 1).
3206                  */
3207                 nkeybits = keybits;
3208                 if (nkeybits < bref->keybits) {
3209                         if (bref->keybits > 64) {
3210                                 kprintf("bad bref chain %p bref %p\n",
3211                                         chain, bref);
3212                                 Debugger("fubar");
3213                         }
3214                         nkeybits = bref->keybits;
3215                 }
3216                 while (nkeybits < 64 &&
3217                        (~(((hammer2_key_t)1 << nkeybits) - 1) &
3218                         (key ^ bref->key)) != 0) {
3219                         ++nkeybits;
3220                 }
3221
3222                 /*
3223                  * If the new key range is larger we have to determine
3224                  * which side of the new key range the existing keys fall
3225                  * under by checking the high bit, then collapsing the
3226                  * locount into the hicount or vise-versa.
3227                  */
3228                 if (keybits != nkeybits) {
3229                         if (((hammer2_key_t)1 << (nkeybits - 1)) & key) {
3230                                 hicount += locount;
3231                                 locount = 0;
3232                         } else {
3233                                 locount += hicount;
3234                                 hicount = 0;
3235                         }
3236                         keybits = nkeybits;
3237                 }
3238
3239                 /*
3240                  * The newly scanned key will be in the lower half or the
3241                  * upper half of the (new) key range.
3242                  */
3243                 if (((hammer2_key_t)1 << (nkeybits - 1)) & bref->key)
3244                         ++hicount;
3245                 else
3246                         ++locount;
3247
3248                 if (key_next == 0)
3249                         break;
3250                 key_beg = key_next;
3251         }
3252         spin_unlock(&parent->core.cst.spin);
3253         bref = NULL;    /* now invalid (safety) */
3254
3255         /*
3256          * Adjust keybits to represent half of the full range calculated
3257          * above (radix 63 max)
3258          */
3259         --keybits;
3260
3261         /*
3262          * Select whichever half contains the most elements.  Theoretically
3263          * we can select either side as long as it contains at least one
3264          * element (in order to ensure that a free slot is present to hold
3265          * the indirect block).
3266          */
3267         if (hammer2_indirect_optimize) {
3268                 /*
3269                  * Insert node for least number of keys, this will arrange
3270                  * the first few blocks of a large file or the first few
3271                  * inodes in a directory with fewer indirect blocks when
3272                  * created linearly.
3273                  */
3274                 if (hicount < locount && hicount != 0)
3275                         key |= (hammer2_key_t)1 << keybits;
3276                 else
3277                         key &= ~(hammer2_key_t)1 << keybits;
3278         } else {
3279                 /*
3280                  * Insert node for most number of keys, best for heavily
3281                  * fragmented files.
3282                  */
3283                 if (hicount > locount)
3284                         key |= (hammer2_key_t)1 << keybits;
3285                 else
3286                         key &= ~(hammer2_key_t)1 << keybits;
3287         }
3288         *keyp = key;
3289
3290         return (keybits);
3291 }
3292
3293 /*
3294  * Sets CHAIN_DELETED and remove the chain's blockref from the parent if
3295  * it exists.
3296  *
3297  * Both parent and chain must be locked exclusively.
3298  *
3299  * This function will modify the parent if the blockref requires removal
3300  * from the parent's block table.
3301  *
3302  * This function is NOT recursive.  Any entity already pushed into the
3303  * chain (such as an inode) may still need visibility into its contents,
3304  * as well as the ability to read and modify the contents.  For example,
3305  * for an unlinked file which is still open.
3306  */
3307 void
3308 hammer2_chain_delete(hammer2_trans_t *trans, hammer2_chain_t *parent,
3309                      hammer2_chain_t *chain, int flags)
3310 {
3311         KKASSERT(ccms_thread_lock_owned(&chain->core.cst));
3312
3313         /*
3314          * Nothing to do if already marked.
3315          *
3316          * We need the spinlock on the core whos RBTREE contains chain
3317          * to protect against races.
3318          */
3319         if ((chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
3320                 KKASSERT((chain->flags & HAMMER2_CHAIN_DELETED) == 0 &&
3321                          chain->parent == parent);
3322                 _hammer2_chain_delete_helper(trans, parent, chain, flags);
3323         }
3324
3325         if (flags & HAMMER2_DELETE_PERMANENT) {
3326                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_DESTROY);
3327                 hammer2_flush(trans, chain);
3328         } else {
3329                 /* XXX might not be needed */
3330                 hammer2_chain_setflush(trans, chain);
3331         }
3332 }
3333
3334 /*
3335  * Returns the index of the nearest element in the blockref array >= elm.
3336  * Returns (count) if no element could be found.
3337  *
3338  * Sets *key_nextp to the next key for loop purposes but does not modify
3339  * it if the next key would be higher than the current value of *key_nextp.
3340  * Note that *key_nexp can overflow to 0, which should be tested by the
3341  * caller.
3342  *
3343  * (*cache_indexp) is a heuristic and can be any value without effecting
3344  * the result.
3345  *
3346  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
3347  *           held through the operation.
3348  */
3349 static int
3350 hammer2_base_find(hammer2_chain_t *parent,
3351                   hammer2_blockref_t *base, int count,
3352                   int *cache_indexp, hammer2_key_t *key_nextp,
3353                   hammer2_key_t key_beg, hammer2_key_t key_end)
3354 {
3355         hammer2_blockref_t *scan;
3356         hammer2_key_t scan_end;
3357         int i;
3358         int limit;
3359
3360         /*
3361          * Require the live chain's already have their core's counted
3362          * so we can optimize operations.
3363          */
3364         KKASSERT(parent->core.flags & HAMMER2_CORE_COUNTEDBREFS);
3365
3366         /*
3367          * Degenerate case
3368          */
3369         if (count == 0 || base == NULL)
3370                 return(count);
3371
3372         /*
3373          * Sequential optimization using *cache_indexp.  This is the most
3374          * likely scenario.
3375          *
3376          * We can avoid trailing empty entries on live chains, otherwise
3377          * we might have to check the whole block array.
3378          */
3379         i = *cache_indexp;
3380         cpu_ccfence();
3381         limit = parent->core.live_zero;
3382         if (i >= limit)
3383                 i = limit - 1;
3384         if (i < 0)
3385                 i = 0;
3386         KKASSERT(i < count);
3387
3388         /*
3389          * Search backwards
3390          */
3391         scan = &base[i];
3392         while (i > 0 && (scan->type == 0 || scan->key > key_beg)) {
3393                 --scan;
3394                 --i;
3395         }
3396         *cache_indexp = i;
3397
3398         /*
3399          * Search forwards, stop when we find a scan element which
3400          * encloses the key or until we know that there are no further
3401          * elements.
3402          */
3403         while (i < count) {
3404                 if (scan->type != 0) {
3405                         scan_end = scan->key +
3406                                    ((hammer2_key_t)1 << scan->keybits) - 1;
3407                         if (scan->key > key_beg || scan_end >= key_beg)
3408                                 break;
3409                 }
3410                 if (i >= limit)
3411                         return (count);
3412                 ++scan;
3413                 ++i;
3414         }
3415         if (i != count) {
3416                 *cache_indexp = i;
3417                 if (i >= limit) {
3418                         i = count;
3419                 } else {
3420                         scan_end = scan->key +
3421                                    ((hammer2_key_t)1 << scan->keybits);
3422                         if (scan_end && (*key_nextp > scan_end ||
3423                                          *key_nextp == 0)) {
3424                                 *key_nextp = scan_end;
3425                         }
3426                 }
3427         }
3428         return (i);
3429 }
3430
3431 /*
3432  * Do a combined search and return the next match either from the blockref
3433  * array or from the in-memory chain.  Sets *bresp to the returned bref in
3434  * both cases, or sets it to NULL if the search exhausted.  Only returns
3435  * a non-NULL chain if the search matched from the in-memory chain.
3436  *
3437  * When no in-memory chain has been found and a non-NULL bref is returned
3438  * in *bresp.
3439  *
3440  *
3441  * The returned chain is not locked or referenced.  Use the returned bref
3442  * to determine if the search exhausted or not.  Iterate if the base find
3443  * is chosen but matches a deleted chain.
3444  *
3445  * WARNING!  Must be called with parent's spinlock held.  Spinlock remains
3446  *           held through the operation.
3447  */
3448 static hammer2_chain_t *
3449 hammer2_combined_find(hammer2_chain_t *parent,
3450                       hammer2_blockref_t *base, int count,
3451                       int *cache_indexp, hammer2_key_t *key_nextp,
3452                       hammer2_key_t key_beg, hammer2_key_t key_end,
3453                       hammer2_blockref_t **bresp)
3454 {
3455         hammer2_blockref_t *bref;
3456         hammer2_chain_t *chain;
3457         int i;
3458
3459         /*
3460          * Lookup in block array and in rbtree.
3461          */
3462         *key_nextp = key_end + 1;
3463         i = hammer2_base_find(parent, base, count, cache_indexp,
3464                               key_nextp, key_beg, key_end);
3465         chain = hammer2_chain_find(parent, key_nextp, key_beg, key_end);
3466
3467         /*
3468          * Neither matched
3469          */
3470         if (i == count && chain == NULL) {
3471                 *bresp = NULL;
3472                 return(NULL);
3473         }
3474
3475         /*
3476          * Only chain matched.
3477          */
3478         if (i == count) {
3479                 bref = &chain->bref;
3480                 goto found;
3481         }
3482
3483         /*
3484          * Only blockref matched.
3485          */
3486         if (chain == NULL) {
3487                 bref = &base[i];
3488                 goto found;
3489         }
3490
3491         /*
3492          * Both in-memory and blockref matched, select the nearer element.
3493          *
3494          * If both are flush with the left-hand side or both are the
3495          * same distance away, select the chain.  In this situation the
3496          * chain must have been loaded from the matching blockmap.
3497          */
3498         if ((chain->bref.key <= key_beg && base[i].key <= key_beg) ||
3499             chain->bref.key == base[i].key) {
3500                 KKASSERT(chain->bref.key == base[i].key);
3501                 bref = &chain->bref;
3502                 goto found;
3503         }
3504
3505         /*
3506          * Select the nearer key
3507          */
3508         if (chain->bref.key < base[i].key) {
3509                 bref = &chain->bref;
3510         } else {
3511                 bref = &base[i];
3512                 chain = NULL;
3513         }
3514
3515         /*
3516          * If the bref is out of bounds we've exhausted our search.
3517          */
3518 found:
3519         if (bref->key > key_end) {
3520                 *bresp = NULL;
3521                 chain = NULL;
3522         } else {
3523                 *bresp = bref;
3524         }
3525         return(chain);
3526 }
3527
3528 /*
3529  * Locate the specified block array element and delete it.  The element
3530  * must exist.
3531  *
3532  * The spin lock on the related chain must be held.
3533  *
3534  * NOTE: live_count was adjusted when the chain was deleted, so it does not
3535  *       need to be adjusted when we commit the media change.
3536  */
3537 void
3538 hammer2_base_delete(hammer2_trans_t *trans, hammer2_chain_t *parent,
3539                     hammer2_blockref_t *base, int count,
3540                     int *cache_indexp, hammer2_chain_t *chain)
3541 {
3542         hammer2_blockref_t *elm = &chain->bref;
3543         hammer2_key_t key_next;
3544         int i;
3545
3546         /*
3547          * Delete element.  Expect the element to exist.
3548          *
3549          * XXX see caller, flush code not yet sophisticated enough to prevent
3550          *     re-flushed in some cases.
3551          */
3552         key_next = 0; /* max range */
3553         i = hammer2_base_find(parent, base, count, cache_indexp,
3554                               &key_next, elm->key, elm->key);
3555         if (i == count || base[i].type == 0 ||
3556             base[i].key != elm->key ||
3557             ((chain->flags & HAMMER2_CHAIN_BMAPUPD) == 0 &&
3558              base[i].keybits != elm->keybits)) {
3559                 spin_unlock(&parent->core.cst.spin);
3560                 panic("delete base %p element not found at %d/%d elm %p\n",
3561                       base, i, count, elm);
3562                 return;
3563         }
3564         bzero(&base[i], sizeof(*base));
3565
3566         /*
3567          * We can only optimize parent->core.live_zero for live chains.
3568          */
3569         if (parent->core.live_zero == i + 1) {
3570                 while (--i >= 0 && base[i].type == 0)
3571                         ;
3572                 parent->core.live_zero = i + 1;
3573         }
3574
3575         /*
3576          * Clear appropriate blockmap flags in chain.
3577          */
3578         atomic_clear_int(&chain->flags, HAMMER2_CHAIN_BMAPPED |
3579                                         HAMMER2_CHAIN_BMAPUPD);
3580 }
3581
3582 /*
3583  * Insert the specified element.  The block array must not already have the
3584  * element and must have space available for the insertion.
3585  *
3586  * The spin lock on the related chain must be held.
3587  *
3588  * NOTE: live_count was adjusted when the chain was deleted, so it does not
3589  *       need to be adjusted when we commit the media change.
3590  */
3591 void
3592 hammer2_base_insert(hammer2_trans_t *trans __unused, hammer2_chain_t *parent,
3593                     hammer2_blockref_t *base, int count,
3594                     int *cache_indexp, hammer2_chain_t *chain)
3595 {
3596         hammer2_blockref_t *elm = &chain->bref;
3597         hammer2_key_t key_next;
3598         hammer2_key_t xkey;
3599         int i;
3600         int j;
3601         int k;
3602         int l;
3603         int u = 1;
3604
3605         /*
3606          * Insert new element.  Expect the element to not already exist
3607          * unless we are replacing it.
3608          *
3609          * XXX see caller, flush code not yet sophisticated enough to prevent
3610          *     re-flushed in some cases.
3611          */
3612         key_next = 0; /* max range */
3613         i = hammer2_base_find(parent, base, count, cache_indexp,
3614                               &key_next, elm->key, elm->key);
3615
3616         /*
3617          * Shortcut fill optimization, typical ordered insertion(s) may not
3618          * require a search.
3619          */
3620         KKASSERT(i >= 0 && i <= count);
3621
3622         /*
3623          * Set appropriate blockmap flags in chain.
3624          */
3625         atomic_set_int(&chain->flags, HAMMER2_CHAIN_BMAPPED);
3626
3627         /*
3628          * We can only optimize parent->core.live_zero for live chains.
3629          */
3630         if (i == count && parent->core.live_zero < count) {
3631                 i = parent->core.live_zero++;
3632                 base[i] = *elm;
3633                 return;
3634         }
3635
3636         xkey = elm->key + ((hammer2_key_t)1 << elm->keybits) - 1;
3637         if (i != count && (base[i].key < elm->key || xkey >= base[i].key)) {
3638                 spin_unlock(&parent->core.cst.spin);
3639                 panic("insert base %p overlapping elements at %d elm %p\n",
3640                       base, i, elm);
3641         }
3642
3643         /*
3644          * Try to find an empty slot before or after.
3645          */
3646         j = i;
3647         k = i;
3648         while (j > 0 || k < count) {
3649                 --j;
3650                 if (j >= 0 && base[j].type == 0) {
3651                         if (j == i - 1) {
3652                                 base[j] = *elm;
3653                         } else {
3654                                 bcopy(&base[j+1], &base[j],
3655                                       (i - j - 1) * sizeof(*base));
3656                                 base[i - 1] = *elm;
3657                      &nbs