xref: /minix3/sys/ufs/chfs/chfs_nodeops.c (revision f14fb602092e015ff630df58e17c2a9cd57d29b3)
1 /*	$NetBSD: chfs_nodeops.c,v 1.1 2011/11/24 15:51:31 ahoka Exp $	*/
2 
3 /*-
4  * Copyright (c) 2010 Department of Software Engineering,
5  *		      University of Szeged, Hungary
6  * Copyright (C) 2010 David Tengeri <dtengeri@inf.u-szeged.hu>
7  * Copyright (C) 2010 Tamas Toth <ttoth@inf.u-szeged.hu>
8  * Copyright (C) 2010 Adam Hoka <ahoka@NetBSD.org>
9  * All rights reserved.
10  *
11  * This code is derived from software contributed to The NetBSD Foundation
12  * by the Department of Software Engineering, University of Szeged, Hungary
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26  * IN NO EVENT SHALL THE AUTHOR 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
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include "chfs.h"
37 
38 /**
39  * chfs_update_eb_dirty - updates dirty and free space, first and
40  *			      last node references
41  * @sbi: CHFS main descriptor structure
42  * @cheb: eraseblock to update
43  * @size: increase dirty space size with this
44  * Returns zero in case of success, %1 in case of fail.
45  */
46 int
47 chfs_update_eb_dirty(struct chfs_mount *chmp,
48     struct chfs_eraseblock *cheb, uint32_t size)
49 {
50 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
51 	KASSERT(!mutex_owned(&chmp->chm_lock_sizes));
52 
53 	if (!size)
54 		return 0;
55 
56 	if (size > cheb->free_size) {
57 		chfs_err("free_size (%d) is less then dirty space (%d) "
58 		    "on block (%d)\n", cheb->free_size, size, cheb->lnr);
59 		return 1;
60 	}
61 	mutex_enter(&chmp->chm_lock_sizes);
62 	//dbg("BEFORE: free_size: %d\n", cheb->free_size);
63 	chfs_change_size_free(chmp, cheb, -size);
64 	chfs_change_size_dirty(chmp, cheb, size);
65 	//dbg(" AFTER: free_size: %d\n", cheb->free_size);
66 	mutex_exit(&chmp->chm_lock_sizes);
67 	return 0;
68 }
69 
70 /**
71  * chfs_add_node_to_list - adds a data node ref to vnode cache's dnode list
72  * @sbi: super block informations
73  * @new: node ref to insert
74  * @list: head of the list
75  * This function inserts a data node ref to the list of vnode cache.
76  * The list is sorted by data node's lnr and offset.
77  */
78 void
79 chfs_add_node_to_list(struct chfs_mount *chmp,
80     struct chfs_vnode_cache *vc,
81     struct chfs_node_ref *new, struct chfs_node_ref **list)
82 {
83 	struct chfs_node_ref *nextref = *list;
84 	struct chfs_node_ref *prevref = NULL;
85 
86 	while (nextref && nextref != (struct chfs_node_ref *)vc &&
87 	    (nextref->nref_lnr <= new->nref_lnr)) {
88 		if (nextref->nref_lnr == new->nref_lnr) {
89 			while (nextref && nextref !=
90 			    (struct chfs_node_ref *)vc &&
91 			    (CHFS_GET_OFS(nextref->nref_offset) <
92 				CHFS_GET_OFS(new->nref_offset))) {
93 				prevref = nextref;
94 				nextref = nextref->nref_next;
95 			}
96 			break;
97 		}
98 		prevref = nextref;
99 		nextref = nextref->nref_next;
100 	}
101 
102 	if (nextref && nextref != (struct chfs_node_ref *)vc &&
103 	    nextref->nref_lnr == new->nref_lnr &&
104 	    CHFS_GET_OFS(nextref->nref_offset) ==
105 	    CHFS_GET_OFS(new->nref_offset)) {
106 		new->nref_next = nextref->nref_next;
107 	} else {
108 		new->nref_next = nextref;
109 	}
110 
111 	if (prevref) {
112 		prevref->nref_next = new;
113 	} else {
114 		*list = new;
115 	}
116 }
117 
118 void
119 chfs_add_fd_to_inode(struct chfs_mount *chmp,
120     struct chfs_inode *parent, struct chfs_dirent *new)
121 {
122 //	struct chfs_dirent **prev = &parent->dents;
123 	struct chfs_dirent *fd, *tmpfd;
124 
125 	if (new->version > parent->chvc->highest_version) {
126 		parent->chvc->highest_version = new->version;
127 	}
128 
129 	//mutex_enter(&parent->inode_lock);
130 	TAILQ_FOREACH_SAFE(fd, &parent->dents, fds, tmpfd) {
131 		if (fd->nhash > new->nhash) {
132 			/* insert new before fd */
133 			TAILQ_INSERT_BEFORE(fd, new, fds);
134 			return;
135 		} else if (fd->nhash == new->nhash &&
136 		    !strcmp(fd->name, new->name)) {
137 			if (new->version > fd->version) {
138 //				new->next = fd->next;
139 				/* replace fd with new */
140 				TAILQ_INSERT_BEFORE(fd, new, fds);
141 				TAILQ_REMOVE(&parent->dents, fd, fds);
142 				if (fd->nref) {
143 					chfs_mark_node_obsolete(chmp,
144 					    fd->nref);
145 				}
146 				chfs_free_dirent(fd);
147 //				*prev = new;//XXX
148 			} else {
149 				chfs_mark_node_obsolete(chmp, new->nref);
150 				chfs_free_dirent(new);
151 			}
152 			return;
153 		}
154 	}
155 	/* if we couldnt fit it elsewhere, lets add to the end */
156 	/* FIXME insert tail or insert head? */
157 	TAILQ_INSERT_HEAD(&parent->dents, new, fds);
158 	//mutex_exit(&parent->inode_lock);
159 #if 0
160    	while ((*prev) && (*prev)->nhash <= new->nhash) {
161 		if ((*prev)->nhash == new->nhash &&
162 		    !strcmp((*prev)->name, new->name)) {
163 			if (new->version > (*prev)->version) {
164 				new->next = (*prev)->next;
165 				if ((*prev)->nref) {
166 					chfs_mark_node_obsolete(chmp,
167 					    (*prev)->nref);
168 				}
169 				chfs_free_dirent(*prev);
170 				*prev = new;
171 			} else {
172 				chfs_mark_node_obsolete(chmp, new->nref);
173 				chfs_free_dirent(new);
174 			}
175 			return;
176 		}
177 		prev = &((*prev)->next);
178 	}
179 
180 	new->next = *prev;
181 	*prev = new;
182 #endif
183 }
184 
185 void
186 chfs_add_vnode_ref_to_vc(struct chfs_mount *chmp,
187     struct chfs_vnode_cache *vc, struct chfs_node_ref *new)
188 {
189 	if ((struct chfs_vnode_cache*)(vc->v) != vc) {
190 		chfs_mark_node_obsolete(chmp, vc->v);
191 		new->nref_next = vc->v->nref_next;
192 	} else {
193 		new->nref_next = vc->v;
194 	}
195 	vc->v = new;
196 }
197 
198 struct chfs_node_ref *
199 chfs_nref_next(struct chfs_node_ref *nref)
200 {
201 //	dbg("check nref: %u - %u\n", nref->nref_lnr, nref->nref_offset);
202 	nref++;
203 //	dbg("next nref: %u - %u\n", nref->nref_lnr, nref->nref_offset);
204 	if (nref->nref_lnr == REF_LINK_TO_NEXT) {
205 		//End of chain
206 		if (!nref->nref_next)
207 			return NULL;
208 
209 		nref = nref->nref_next;
210 	}
211 	//end of chain
212 	if (nref->nref_lnr == REF_EMPTY_NODE)
213 		return NULL;
214 
215 	return nref;
216 }
217 
218 int
219 chfs_nref_len(struct chfs_mount *chmp,
220     struct chfs_eraseblock *cheb, struct chfs_node_ref *nref)
221 {
222 	struct chfs_node_ref *next;
223 
224 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
225 
226 	if (!cheb)
227 		cheb = &chmp->chm_blocks[nref->nref_lnr];
228 
229 	next = chfs_nref_next(nref);
230 
231 	if (!next) {
232 		//dbg("next null\n");
233 		return chmp->chm_ebh->eb_size - cheb->free_size -
234 		    CHFS_GET_OFS(nref->nref_offset);
235 	}
236 	//dbg("size: %d\n", CHFS_GET_OFS(next->nref_offset) - CHFS_GET_OFS(nref->nref_offset));
237 	return CHFS_GET_OFS(next->nref_offset) -
238 	    CHFS_GET_OFS(nref->nref_offset);
239 }
240 
241 /**
242  * chfs_mark_node_obsolete - marks a node obsolete
243  */
244 void
245 chfs_mark_node_obsolete(struct chfs_mount *chmp,
246     struct chfs_node_ref *nref)
247 {
248 	int len;
249 	struct chfs_eraseblock *cheb;
250 
251 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
252 
253 	KASSERT(!CHFS_REF_OBSOLETE(nref));
254 
255 	KASSERT(nref->nref_lnr <= chmp->chm_ebh->peb_nr);
256 	cheb = &chmp->chm_blocks[nref->nref_lnr];
257 
258 #ifdef DIAGNOSTIC
259 	if (cheb->used_size + cheb->free_size + cheb->dirty_size +
260 	    cheb->unchecked_size + cheb->wasted_size != chmp->chm_ebh->eb_size) {
261 		dbg("eraseblock leak detected!\nused: %u\nfree: %u\n"
262 		    "dirty: %u\nunchecked: %u\nwasted: %u\ntotal: %u\nshould be: %zu\n",
263 		    cheb->used_size, cheb->free_size, cheb->dirty_size,
264 		    cheb->unchecked_size, cheb->wasted_size, cheb->used_size + cheb->free_size +
265 		    cheb->dirty_size + cheb->unchecked_size + cheb->wasted_size,
266 		    chmp->chm_ebh->eb_size);
267 	}
268 #endif
269 
270 	len = chfs_nref_len(chmp, cheb, nref);
271 	//dbg("len: %u\n", len);
272 	//dbg("1. used: %u\n", cheb->used_size);
273 
274 	mutex_enter(&chmp->chm_lock_sizes);
275 
276 	if (CHFS_REF_FLAGS(nref) == CHFS_UNCHECKED_NODE_MASK) {
277 		//dbg("UNCHECKED mark an unchecked node\n");
278 		chfs_change_size_unchecked(chmp, cheb, -len);
279 		//dbg("unchecked: %u\n", chmp->chm_unchecked_size);
280 	} else {
281 		chfs_change_size_used(chmp, cheb, -len);
282 
283 		//dbg("2. used: %u\n", cheb->used_size);
284 		KASSERT(cheb->used_size <= chmp->chm_ebh->eb_size);
285 	}
286 	chfs_change_size_dirty(chmp, cheb, len);
287 
288 #ifdef DIAGNOSTIC
289 	if (cheb->used_size + cheb->free_size + cheb->dirty_size +
290 	    cheb->unchecked_size + cheb->wasted_size != chmp->chm_ebh->eb_size) {
291 		panic("eraseblock leak detected!\nused: %u\nfree: %u\n"
292 		    "dirty: %u\nunchecked: %u\nwasted: %u\ntotal: %u\nshould be: %zu\n",
293 		    cheb->used_size, cheb->free_size, cheb->dirty_size,
294 		    cheb->unchecked_size, cheb->wasted_size, cheb->used_size + cheb->free_size +
295 		    cheb->dirty_size + cheb->unchecked_size + cheb->wasted_size,
296 		    chmp->chm_ebh->eb_size);
297 	}
298 #endif
299 	nref->nref_offset = CHFS_GET_OFS(nref->nref_offset) |
300 	    CHFS_OBSOLETE_NODE_MASK;
301 
302 	if (chmp->chm_flags & CHFS_MP_FLAG_SCANNING) {
303 		/*Scan is in progress, do nothing now*/
304 		mutex_exit(&chmp->chm_lock_sizes);
305 		return;
306 	}
307 
308 	if (cheb == chmp->chm_nextblock) {
309 		dbg("Not moving nextblock to dirty/erase_pending list\n");
310 	} else if (!cheb->used_size && !cheb->unchecked_size) {
311 		if (cheb == chmp->chm_gcblock) {
312 			dbg("gcblock is completely dirtied\n");
313 			chmp->chm_gcblock = NULL;
314 		} else {
315 			//remove from a tailq, but we don't know which tailq contains this cheb
316 			//so we remove it from the dirty list now
317 			//TAILQ_REMOVE(&chmp->chm_dirty_queue, cheb, queue);
318 			int removed = 0;
319 			struct chfs_eraseblock *eb, *tmpeb;
320 			//XXX ugly code
321 			TAILQ_FOREACH_SAFE(eb, &chmp->chm_free_queue, queue, tmpeb) {
322 				if (eb == cheb) {
323 					TAILQ_REMOVE(&chmp->chm_free_queue, cheb, queue);
324 					removed = 1;
325 					break;
326 				}
327 			}
328 			if (removed == 0) {
329 				TAILQ_FOREACH_SAFE(eb, &chmp->chm_dirty_queue, queue, tmpeb) {
330 					if (eb == cheb) {
331 						TAILQ_REMOVE(&chmp->chm_dirty_queue, cheb, queue);
332 						removed = 1;
333 						break;
334 					}
335 				}
336 			}
337 			if (removed == 0) {
338 				TAILQ_FOREACH_SAFE(eb, &chmp->chm_very_dirty_queue, queue, tmpeb) {
339 					if (eb == cheb) {
340 						TAILQ_REMOVE(&chmp->chm_very_dirty_queue, cheb, queue);
341 						removed = 1;
342 						break;
343 					}
344 				}
345 			}
346 			if (removed == 0) {
347 				TAILQ_FOREACH_SAFE(eb, &chmp->chm_clean_queue, queue, tmpeb) {
348 					if (eb == cheb) {
349 						TAILQ_REMOVE(&chmp->chm_clean_queue, cheb, queue);
350 						removed = 1;
351 						break;
352 					}
353 				}
354 			}
355 		}
356 		if (chmp->chm_wbuf_len) {
357 			dbg("Adding block to erasable pending wbuf queue\n");
358 			TAILQ_INSERT_TAIL(&chmp->chm_erasable_pending_wbuf_queue,
359 			    cheb, queue);
360 		} else {
361 			TAILQ_INSERT_TAIL(&chmp->chm_erase_pending_queue,
362 			    cheb, queue);
363 			chmp->chm_nr_erasable_blocks++;
364 		}
365 		chfs_remap_leb(chmp);
366 	} else if (cheb == chmp->chm_gcblock) {
367 		dbg("Not moving gcblock to dirty list\n");
368 	} else if (cheb->dirty_size > MAX_DIRTY_TO_CLEAN &&
369 	    cheb->dirty_size - len <= MAX_DIRTY_TO_CLEAN) {
370 		dbg("Freshly dirtied, remove it from clean queue and "
371 		    "add it to dirty\n");
372 		TAILQ_REMOVE(&chmp->chm_clean_queue, cheb, queue);
373 		TAILQ_INSERT_TAIL(&chmp->chm_dirty_queue, cheb, queue);
374 	} else if (VERY_DIRTY(chmp, cheb->dirty_size) &&
375 	    !VERY_DIRTY(chmp, cheb->dirty_size - len)) {
376 		dbg("Becomes now very dirty, remove it from dirty "
377 		    "queue and add it to very dirty\n");
378 		TAILQ_REMOVE(&chmp->chm_dirty_queue, cheb, queue);
379 		TAILQ_INSERT_TAIL(&chmp->chm_very_dirty_queue, cheb, queue);
380 	} else {
381 		dbg("Leave cheb where it is\n");
382 	}
383 	mutex_exit(&chmp->chm_lock_sizes);
384 	return;
385 }
386 
387 /**
388  * chfs_close_eraseblock - close an eraseblock
389  * @chmp: chfs mount structure
390  * @cheb: eraseblock informations
391  *
392  * This function close the physical chain of the nodes on the eraseblock,
393  * convert its free size to dirty and add it to clean, dirty or very dirty list.
394  */
395 int
396 chfs_close_eraseblock(struct chfs_mount *chmp,
397     struct chfs_eraseblock *cheb)
398 {
399 	uint32_t offset;
400 	struct chfs_node_ref *nref;
401 
402 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
403 
404 	offset = chmp->chm_ebh->eb_size - cheb->free_size;
405 
406 	// Close the chain
407 	nref = chfs_alloc_node_ref(cheb);
408 	if (!nref)
409 		return ENOMEM;
410 
411 	nref->nref_next = NULL;
412 	nref->nref_offset = offset;
413 
414 	// Mark space as dirty
415 	chfs_update_eb_dirty(chmp, cheb, cheb->free_size);
416 
417 	if (cheb->dirty_size < MAX_DIRTY_TO_CLEAN) {
418 		TAILQ_INSERT_TAIL(&chmp->chm_clean_queue, cheb, queue);
419 	} else if (VERY_DIRTY(chmp, cheb->dirty_size)) {
420 		TAILQ_INSERT_TAIL(&chmp->chm_very_dirty_queue, cheb, queue);
421 	} else {
422 		TAILQ_INSERT_TAIL(&chmp->chm_dirty_queue, cheb, queue);
423 	}
424 	return 0;
425 }
426 
427 int
428 chfs_reserve_space_normal(struct chfs_mount *chmp, uint32_t size, int prio)
429 {
430 	int ret;
431 
432 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
433 
434 	mutex_enter(&chmp->chm_lock_sizes);
435 	while (chmp->chm_nr_free_blocks + chmp->chm_nr_erasable_blocks < chmp->chm_resv_blocks_write) {
436 		dbg("free: %d, erasable: %d, resv: %d\n", chmp->chm_nr_free_blocks, chmp->chm_nr_erasable_blocks, chmp->chm_resv_blocks_write);
437 		uint32_t avail, dirty;
438 		if (prio == ALLOC_DELETION && chmp->chm_nr_free_blocks + chmp->chm_nr_erasable_blocks >= chmp->chm_resv_blocks_deletion)
439 			break;
440 
441 		dirty = chmp->chm_dirty_size - chmp->chm_nr_erasable_blocks * chmp->chm_ebh->eb_size + chmp->chm_unchecked_size;
442 		if (dirty < chmp->chm_nospc_dirty) {
443 			dbg("dirty: %u < nospc_dirty: %u\n", dirty, chmp->chm_nospc_dirty);
444 			ret = ENOSPC;
445 			mutex_exit(&chmp->chm_lock_sizes);
446 			goto out;
447 		}
448 
449 		avail = chmp->chm_free_size - (chmp->chm_resv_blocks_write * chmp->chm_ebh->eb_size);
450 		if (size > avail) {
451 			dbg("size: %u > avail: %u\n", size, avail);
452 			ret = ENOSPC;
453 			mutex_exit(&chmp->chm_lock_sizes);
454 			goto out;
455 		}
456 
457 		mutex_exit(&chmp->chm_lock_sizes);
458 		ret = chfs_gcollect_pass(chmp);
459 		/* gcollect_pass exits chm_lock_mountfields */
460 		mutex_enter(&chmp->chm_lock_mountfields);
461 		mutex_enter(&chmp->chm_lock_sizes);
462 
463 		if (chmp->chm_nr_erasable_blocks ||
464 		    !TAILQ_EMPTY(&chmp->chm_erasable_pending_wbuf_queue) ||
465 		    ret == EAGAIN) {
466 			ret = chfs_remap_leb(chmp);
467 		}
468 
469 		if (ret) {
470 			mutex_exit(&chmp->chm_lock_sizes);
471 			goto out;
472 		}
473 	}
474 
475 	mutex_exit(&chmp->chm_lock_sizes);
476 	ret = chfs_reserve_space(chmp, size);
477 out:
478 	return ret;
479 }
480 
481 
482 int
483 chfs_reserve_space_gc(struct chfs_mount *chmp, uint32_t size)
484 {
485 	int ret;
486 
487 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
488 
489 	mutex_enter(&chmp->chm_lock_sizes);
490 	chfs_remap_leb(chmp);
491 
492 	if (size > chmp->chm_free_size) {
493 		dbg("size: %u\n", size);
494 		mutex_exit(&chmp->chm_lock_sizes);
495 		return ENOSPC;
496 	}
497 
498 	mutex_exit(&chmp->chm_lock_sizes);
499 	ret = chfs_reserve_space(chmp, size);
500 	return ret;
501 }
502 
503 /**
504  * chfs_reserve_space - finds a block which free size is >= requested size
505  * @chmp: chfs mount point
506  * @size: requested size
507  * @len: reserved spaced will be returned in this variable;
508  * Returns zero in case of success, error code in case of fail.
509  */
510 int
511 chfs_reserve_space(struct chfs_mount *chmp, uint32_t size)
512 {
513 	//TODO define minimum reserved blocks, which is needed for writing
514 	//TODO check we have enough free blocks to write
515 	//TODO if no: need erase and GC
516 
517 	int err;
518 	struct chfs_eraseblock *cheb;
519 
520 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
521 	KASSERT(!mutex_owned(&chmp->chm_lock_sizes));
522 
523 	cheb = chmp->chm_nextblock;
524 	//if (cheb)
525 	    //dbg("cheb->free_size %u\n", cheb->free_size);
526 	if (cheb && size > cheb->free_size) {
527 		dbg("size: %u > free_size: %u\n", size, cheb->free_size);
528 		/*
529 		 * There isn't enough space on this eraseblock, we mark this as
530 		 * dirty and close the physical chain of the node refs.
531 		 */
532 		//Write out pending data if any
533 		if (chmp->chm_wbuf_len) {
534 			chfs_flush_pending_wbuf(chmp);
535 			//FIXME need goto restart here?
536 		}
537 
538 		while (chmp->chm_wbuf_ofs < chmp->chm_ebh->eb_size) {
539 			dbg("wbuf ofs: %zu - eb_size: %zu\n",
540 			    chmp->chm_wbuf_ofs, chmp->chm_ebh->eb_size);
541 			chfs_flush_pending_wbuf(chmp);
542 		}
543 
544 		if (!(chmp->chm_wbuf_ofs % chmp->chm_ebh->eb_size) && !chmp->chm_wbuf_len)
545 			chmp->chm_wbuf_ofs = 0xffffffff;
546 
547 		err = chfs_close_eraseblock(chmp, cheb);
548 		if (err)
549 			return err;
550 
551 		cheb = NULL;
552 	}
553 	if (!cheb) {
554 		//get a block for nextblock
555 		if (TAILQ_EMPTY(&chmp->chm_free_queue)) {
556 			// If this succeeds there will be a block on free_queue
557 			dbg("cheb remap (free: %d)\n", chmp->chm_nr_free_blocks);
558 			err = chfs_remap_leb(chmp);
559 			if (err)
560 				return err;
561 		}
562 		cheb = TAILQ_FIRST(&chmp->chm_free_queue);
563 		TAILQ_REMOVE(&chmp->chm_free_queue, cheb, queue);
564 		chmp->chm_nextblock = cheb;
565 		chmp->chm_nr_free_blocks--;
566 	}
567 
568 	return 0;
569 }
570 
571