xref: /dragonfly/sys/vfs/hammer2/hammer2_vfsops.c (revision 3c639e0c)
1 /*
2  * Copyright (c) 2011-2015 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  * by Daniel Flores (GSOC 2013 - mentored by Matthew Dillon, compression)
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/nlookup.h>
39 #include <sys/vnode.h>
40 #include <sys/mount.h>
41 #include <sys/fcntl.h>
42 #include <sys/buf.h>
43 #include <sys/uuid.h>
44 #include <sys/vfsops.h>
45 #include <sys/sysctl.h>
46 #include <sys/socket.h>
47 #include <sys/objcache.h>
48 
49 #include <sys/proc.h>
50 #include <sys/namei.h>
51 #include <sys/mountctl.h>
52 #include <sys/dirent.h>
53 #include <sys/uio.h>
54 
55 #include <sys/mutex.h>
56 #include <sys/mutex2.h>
57 
58 #include "hammer2.h"
59 #include "hammer2_disk.h"
60 #include "hammer2_mount.h"
61 #include "hammer2_lz4.h"
62 
63 #include "zlib/hammer2_zlib.h"
64 
65 #define REPORT_REFS_ERRORS 1	/* XXX remove me */
66 
67 MALLOC_DEFINE(M_OBJCACHE, "objcache", "Object Cache");
68 
69 struct hammer2_sync_info {
70 	int error;
71 	int waitfor;
72 };
73 
74 TAILQ_HEAD(hammer2_mntlist, hammer2_dev);
75 static struct hammer2_mntlist hammer2_mntlist;
76 
77 struct hammer2_pfslist hammer2_pfslist;
78 struct lock hammer2_mntlk;
79 
80 int hammer2_debug;
81 int hammer2_cluster_read = 4;		/* physical read-ahead */
82 int hammer2_cluster_write = 0;		/* bdwrite() so later inval works */
83 int hammer2_dedup_enable = 1;
84 int hammer2_inval_enable = 0;
85 int hammer2_flush_pipe = 100;
86 int hammer2_synchronous_flush = 1;
87 int hammer2_dio_count;
88 long hammer2_chain_allocs;
89 long hammer2_chain_frees;
90 long hammer2_limit_dirty_chains;
91 long hammer2_count_modified_chains;
92 long hammer2_iod_invals;
93 long hammer2_iod_file_read;
94 long hammer2_iod_meta_read;
95 long hammer2_iod_indr_read;
96 long hammer2_iod_fmap_read;
97 long hammer2_iod_volu_read;
98 long hammer2_iod_file_write;
99 long hammer2_iod_file_wembed;
100 long hammer2_iod_file_wzero;
101 long hammer2_iod_file_wdedup;
102 long hammer2_iod_meta_write;
103 long hammer2_iod_indr_write;
104 long hammer2_iod_fmap_write;
105 long hammer2_iod_volu_write;
106 
107 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
108 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
109 		"Buffer used for compression.");
110 
111 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
112 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
113 		"Buffer used for decompression.");
114 
115 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
116 
117 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
118 	   &hammer2_debug, 0, "");
119 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_read, CTLFLAG_RW,
120 	   &hammer2_cluster_read, 0, "");
121 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_write, CTLFLAG_RW,
122 	   &hammer2_cluster_write, 0, "");
123 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dedup_enable, CTLFLAG_RW,
124 	   &hammer2_dedup_enable, 0, "");
125 SYSCTL_INT(_vfs_hammer2, OID_AUTO, inval_enable, CTLFLAG_RW,
126 	   &hammer2_inval_enable, 0, "");
127 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
128 	   &hammer2_flush_pipe, 0, "");
129 SYSCTL_INT(_vfs_hammer2, OID_AUTO, synchronous_flush, CTLFLAG_RW,
130 	   &hammer2_synchronous_flush, 0, "");
131 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_allocs, CTLFLAG_RW,
132 	   &hammer2_chain_allocs, 0, "");
133 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_frees, CTLFLAG_RW,
134 	   &hammer2_chain_frees, 0, "");
135 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
136 	   &hammer2_limit_dirty_chains, 0, "");
137 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, count_modified_chains, CTLFLAG_RW,
138 	   &hammer2_count_modified_chains, 0, "");
139 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
140 	   &hammer2_dio_count, 0, "");
141 
142 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_invals, CTLFLAG_RW,
143 	   &hammer2_iod_invals, 0, "");
144 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
145 	   &hammer2_iod_file_read, 0, "");
146 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
147 	   &hammer2_iod_meta_read, 0, "");
148 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
149 	   &hammer2_iod_indr_read, 0, "");
150 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
151 	   &hammer2_iod_fmap_read, 0, "");
152 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
153 	   &hammer2_iod_volu_read, 0, "");
154 
155 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
156 	   &hammer2_iod_file_write, 0, "");
157 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
158 	   &hammer2_iod_file_wembed, 0, "");
159 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
160 	   &hammer2_iod_file_wzero, 0, "");
161 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
162 	   &hammer2_iod_file_wdedup, 0, "");
163 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
164 	   &hammer2_iod_meta_write, 0, "");
165 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
166 	   &hammer2_iod_indr_write, 0, "");
167 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
168 	   &hammer2_iod_fmap_write, 0, "");
169 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
170 	   &hammer2_iod_volu_write, 0, "");
171 
172 long hammer2_check_icrc32;
173 long hammer2_check_xxhash64;
174 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_icrc32, CTLFLAG_RW,
175 	   &hammer2_check_icrc32, 0, "");
176 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_xxhash64, CTLFLAG_RW,
177 	   &hammer2_check_xxhash64, 0, "");
178 
179 static int hammer2_vfs_init(struct vfsconf *conf);
180 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
181 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
182 				struct ucred *cred);
183 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
184 				struct vnode *, struct ucred *);
185 static int hammer2_recovery(hammer2_dev_t *hmp);
186 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
187 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
188 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
189 				struct ucred *cred);
190 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
191 				struct ucred *cred);
192 static int hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
193 				struct fid *fhp, struct vnode **vpp);
194 static int hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp);
195 static int hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
196 				int *exflagsp, struct ucred **credanonp);
197 
198 static int hammer2_install_volume_header(hammer2_dev_t *hmp);
199 static int hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
200 
201 static void hammer2_update_pmps(hammer2_dev_t *hmp);
202 
203 static void hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp);
204 static void hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp,
205 				hammer2_dev_t *hmp);
206 
207 /*
208  * HAMMER2 vfs operations.
209  */
210 static struct vfsops hammer2_vfsops = {
211 	.vfs_init	= hammer2_vfs_init,
212 	.vfs_uninit	= hammer2_vfs_uninit,
213 	.vfs_sync	= hammer2_vfs_sync,
214 	.vfs_mount	= hammer2_vfs_mount,
215 	.vfs_unmount	= hammer2_vfs_unmount,
216 	.vfs_root 	= hammer2_vfs_root,
217 	.vfs_statfs	= hammer2_vfs_statfs,
218 	.vfs_statvfs	= hammer2_vfs_statvfs,
219 	.vfs_vget	= hammer2_vfs_vget,
220 	.vfs_vptofh	= hammer2_vfs_vptofh,
221 	.vfs_fhtovp	= hammer2_vfs_fhtovp,
222 	.vfs_checkexp	= hammer2_vfs_checkexp
223 };
224 
225 MALLOC_DEFINE(M_HAMMER2, "HAMMER2-mount", "");
226 
227 VFS_SET(hammer2_vfsops, hammer2, VFCF_MPSAFE);
228 MODULE_VERSION(hammer2, 1);
229 
230 static
231 int
232 hammer2_vfs_init(struct vfsconf *conf)
233 {
234 	static struct objcache_malloc_args margs_read;
235 	static struct objcache_malloc_args margs_write;
236 	static struct objcache_malloc_args margs_vop;
237 
238 	int error;
239 
240 	error = 0;
241 
242 	if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
243 		error = EINVAL;
244 	if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
245 		error = EINVAL;
246 	if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
247 		error = EINVAL;
248 
249 	if (error)
250 		kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
251 
252 	margs_read.objsize = 65536;
253 	margs_read.mtype = M_HAMMER2_DEBUFFER;
254 
255 	margs_write.objsize = 32768;
256 	margs_write.mtype = M_HAMMER2_CBUFFER;
257 
258 	margs_vop.objsize = sizeof(hammer2_xop_t);
259 	margs_vop.mtype = M_HAMMER2;
260 
261 	/*
262 	 * Note thaht for the XOPS cache we want backing store allocations
263 	 * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
264 	 * confusion), so use the backing store function that does it.  This
265 	 * means that initial XOPS objects are zerod but REUSED objects are
266 	 * not.  So we are responsible for cleaning the object up sufficiently
267 	 * for our needs before objcache_put()ing it back (typically just the
268 	 * FIFO indices).
269 	 */
270 	cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
271 				0, 1, NULL, NULL, NULL,
272 				objcache_malloc_alloc,
273 				objcache_malloc_free,
274 				&margs_read);
275 	cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
276 				0, 1, NULL, NULL, NULL,
277 				objcache_malloc_alloc,
278 				objcache_malloc_free,
279 				&margs_write);
280 	cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
281 				0, 1, NULL, NULL, NULL,
282 				objcache_malloc_alloc_zero,
283 				objcache_malloc_free,
284 				&margs_vop);
285 
286 
287 	lockinit(&hammer2_mntlk, "mntlk", 0, 0);
288 	TAILQ_INIT(&hammer2_mntlist);
289 	TAILQ_INIT(&hammer2_pfslist);
290 
291 	hammer2_limit_dirty_chains = maxvnodes / 10;
292 	if (hammer2_limit_dirty_chains > HAMMER2_LIMIT_DIRTY_CHAINS)
293 		hammer2_limit_dirty_chains = HAMMER2_LIMIT_DIRTY_CHAINS;
294 
295 	return (error);
296 }
297 
298 static
299 int
300 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
301 {
302 	objcache_destroy(cache_buffer_read);
303 	objcache_destroy(cache_buffer_write);
304 	objcache_destroy(cache_xops);
305 	return 0;
306 }
307 
308 /*
309  * Core PFS allocator.  Used to allocate or reference the pmp structure
310  * for PFS cluster mounts and the spmp structure for media (hmp) structures.
311  * The pmp can be passed in or loaded by this function using the chain and
312  * inode data.
313  *
314  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
315  * transactions.  Note that synchronization does not use this field.
316  * (typically frontend operations and synchronization cannot run on the
317  * same PFS node at the same time).
318  *
319  * XXX check locking
320  */
321 hammer2_pfs_t *
322 hammer2_pfsalloc(hammer2_chain_t *chain,
323 		 const hammer2_inode_data_t *ripdata,
324 		 hammer2_tid_t modify_tid, hammer2_dev_t *force_local)
325 {
326 	hammer2_pfs_t *pmp;
327 	hammer2_inode_t *iroot;
328 	int count;
329 	int i;
330 	int j;
331 
332 	pmp = NULL;
333 
334 	/*
335 	 * Locate or create the PFS based on the cluster id.  If ripdata
336 	 * is NULL this is a spmp which is unique and is always allocated.
337 	 *
338 	 * If the device is mounted in local mode all PFSs are considered
339 	 * independent and not part of any cluster (for debugging only).
340 	 */
341 	if (ripdata) {
342 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
343 			if (force_local != pmp->force_local)
344 				continue;
345 			if (force_local == NULL &&
346 			    bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
347 				 sizeof(pmp->pfs_clid)) == 0) {
348 					break;
349 			} else if (force_local && pmp->pfs_names[0] &&
350 			    strcmp(pmp->pfs_names[0], ripdata->filename) == 0) {
351 					break;
352 			}
353 		}
354 	}
355 
356 	if (pmp == NULL) {
357 		pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
358 		pmp->force_local = force_local;
359 		hammer2_trans_manage_init(pmp);
360 		kmalloc_create(&pmp->minode, "HAMMER2-inodes");
361 		kmalloc_create(&pmp->mmsg, "HAMMER2-pfsmsg");
362 		lockinit(&pmp->lock, "pfslk", 0, 0);
363 		lockinit(&pmp->lock_nlink, "h2nlink", 0, 0);
364 		spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
365 		spin_init(&pmp->xop_spin, "h2xop");
366 		spin_init(&pmp->lru_spin, "h2lru");
367 		RB_INIT(&pmp->inum_tree);
368 		TAILQ_INIT(&pmp->sideq);
369 		TAILQ_INIT(&pmp->lru_list);
370 		spin_init(&pmp->list_spin, "hm2pfsalloc_list");
371 
372 		/*
373 		 * Distribute backend operations to threads
374 		 */
375 		for (i = 0; i < HAMMER2_XOPGROUPS; ++i)
376 			hammer2_xop_group_init(pmp, &pmp->xop_groups[i]);
377 
378 		/*
379 		 * Save the last media transaction id for the flusher.  Set
380 		 * initial
381 		 */
382 		if (ripdata)
383 			pmp->pfs_clid = ripdata->meta.pfs_clid;
384 		TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
385 
386 		/*
387 		 * The synchronization thread may start too early, make
388 		 * sure it stays frozen until we are ready to let it go.
389 		 * XXX
390 		 */
391 		/*
392 		pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
393 					 HAMMER2_THREAD_REMASTER;
394 		*/
395 	}
396 
397 	/*
398 	 * Create the PFS's root inode and any missing XOP helper threads.
399 	 */
400 	if ((iroot = pmp->iroot) == NULL) {
401 		iroot = hammer2_inode_get(pmp, NULL, NULL, -1);
402 		if (ripdata)
403 			iroot->meta = ripdata->meta;
404 		pmp->iroot = iroot;
405 		hammer2_inode_ref(iroot);
406 		hammer2_inode_unlock(iroot);
407 	}
408 
409 	/*
410 	 * Stop here if no chain is passed in.
411 	 */
412 	if (chain == NULL)
413 		goto done;
414 
415 	/*
416 	 * When a chain is passed in we must add it to the PFS's root
417 	 * inode, update pmp->pfs_types[], and update the syncronization
418 	 * threads.
419 	 *
420 	 * When forcing local mode, mark the PFS as a MASTER regardless.
421 	 *
422 	 * At the moment empty spots can develop due to removals or failures.
423 	 * Ultimately we want to re-fill these spots but doing so might
424 	 * confused running code. XXX
425 	 */
426 	hammer2_inode_ref(iroot);
427 	hammer2_mtx_ex(&iroot->lock);
428 	j = iroot->cluster.nchains;
429 
430 	kprintf("add PFS to pmp %p[%d]\n", pmp, j);
431 
432 	if (j == HAMMER2_MAXCLUSTER) {
433 		kprintf("hammer2_mount: cluster full!\n");
434 		/* XXX fatal error? */
435 	} else {
436 		KKASSERT(chain->pmp == NULL);
437 		chain->pmp = pmp;
438 		hammer2_chain_ref(chain);
439 		iroot->cluster.array[j].chain = chain;
440 		if (force_local)
441 			pmp->pfs_types[j] = HAMMER2_PFSTYPE_MASTER;
442 		else
443 			pmp->pfs_types[j] = ripdata->meta.pfs_type;
444 		pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
445 		pmp->pfs_hmps[j] = chain->hmp;
446 
447 		/*
448 		 * If the PFS is already mounted we must account
449 		 * for the mount_count here.
450 		 */
451 		if (pmp->mp)
452 			++chain->hmp->mount_count;
453 
454 		/*
455 		 * May have to fixup dirty chain tracking.  Previous
456 		 * pmp was NULL so nothing to undo.
457 		 */
458 		if (chain->flags & HAMMER2_CHAIN_MODIFIED)
459 			hammer2_pfs_memory_inc(pmp);
460 		++j;
461 	}
462 	iroot->cluster.nchains = j;
463 
464 	/*
465 	 * Update nmasters from any PFS inode which is part of the cluster.
466 	 * It is possible that this will result in a value which is too
467 	 * high.  MASTER PFSs are authoritative for pfs_nmasters and will
468 	 * override this value later on.
469 	 *
470 	 * (This informs us of masters that might not currently be
471 	 *  discoverable by this mount).
472 	 */
473 	if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
474 		pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
475 	}
476 
477 	/*
478 	 * Count visible masters.  Masters are usually added with
479 	 * ripdata->meta.pfs_nmasters set to 1.  This detects when there
480 	 * are more (XXX and must update the master inodes).
481 	 */
482 	count = 0;
483 	for (i = 0; i < iroot->cluster.nchains; ++i) {
484 		if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
485 			++count;
486 	}
487 	if (pmp->pfs_nmasters < count)
488 		pmp->pfs_nmasters = count;
489 
490 	/*
491 	 * Create missing synchronization and support threads.
492 	 *
493 	 * Single-node masters (including snapshots) have nothing to
494 	 * synchronize and do not require this thread.
495 	 *
496 	 * Multi-node masters or any number of soft masters, slaves, copy,
497 	 * or other PFS types need the thread.
498 	 *
499 	 * Each thread is responsible for its particular cluster index.
500 	 * We use independent threads so stalls or mismatches related to
501 	 * any given target do not affect other targets.
502 	 */
503 	for (i = 0; i < iroot->cluster.nchains; ++i) {
504 		/*
505 		 * Single-node masters (including snapshots) have nothing
506 		 * to synchronize and will make direct xops support calls,
507 		 * thus they do not require this thread.
508 		 *
509 		 * Note that there can be thousands of snapshots.  We do not
510 		 * want to create thousands of threads.
511 		 */
512 		if (pmp->pfs_nmasters <= 1 &&
513 		    pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
514 			continue;
515 		}
516 
517 		/*
518 		 * Sync support thread
519 		 */
520 		if (pmp->sync_thrs[i].td == NULL) {
521 			hammer2_thr_create(&pmp->sync_thrs[i], pmp,
522 					   "h2nod", i, -1,
523 					   hammer2_primary_sync_thread);
524 		}
525 	}
526 
527 	/*
528 	 * Create missing Xop threads
529 	 *
530 	 * NOTE: We create helper threads for all mounted PFSs or any
531 	 *	 PFSs with 2+ nodes (so the sync thread can update them,
532 	 *	 even if not mounted).
533 	 */
534 	if (pmp->mp || iroot->cluster.nchains >= 2)
535 		hammer2_xop_helper_create(pmp);
536 
537 	hammer2_mtx_unlock(&iroot->lock);
538 	hammer2_inode_drop(iroot);
539 done:
540 	return pmp;
541 }
542 
543 /*
544  * Deallocate an element of a probed PFS.  If destroying and this is a
545  * MASTER, adjust nmasters.
546  *
547  * This function does not physically destroy the PFS element in its device
548  * under the super-root  (see hammer2_ioctl_pfs_delete()).
549  */
550 void
551 hammer2_pfsdealloc(hammer2_pfs_t *pmp, int clindex, int destroying)
552 {
553 	hammer2_inode_t *iroot;
554 	hammer2_chain_t *chain;
555 	int j;
556 
557 	/*
558 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
559 	 * by the flush code.
560 	 */
561 	iroot = pmp->iroot;
562 	if (iroot) {
563 		/*
564 		 * Stop synchronizing
565 		 *
566 		 * XXX flush after acquiring the iroot lock.
567 		 * XXX clean out the cluster index from all inode structures.
568 		 */
569 		hammer2_thr_delete(&pmp->sync_thrs[clindex]);
570 
571 		/*
572 		 * Remove the cluster index from the group.  If destroying
573 		 * the PFS and this is a master, adjust pfs_nmasters.
574 		 */
575 		hammer2_mtx_ex(&iroot->lock);
576 		chain = iroot->cluster.array[clindex].chain;
577 		iroot->cluster.array[clindex].chain = NULL;
578 
579 		switch(pmp->pfs_types[clindex]) {
580 		case HAMMER2_PFSTYPE_MASTER:
581 			if (destroying && pmp->pfs_nmasters > 0)
582 				--pmp->pfs_nmasters;
583 			/* XXX adjust ripdata->meta.pfs_nmasters */
584 			break;
585 		default:
586 			break;
587 		}
588 		pmp->pfs_types[clindex] = HAMMER2_PFSTYPE_NONE;
589 
590 		hammer2_mtx_unlock(&iroot->lock);
591 
592 		/*
593 		 * Release the chain.
594 		 */
595 		if (chain) {
596 			atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
597 			hammer2_chain_drop(chain);
598 		}
599 
600 		/*
601 		 * Terminate all XOP threads for the cluster index.
602 		 */
603 		for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
604 			hammer2_thr_delete(&pmp->xop_groups[j].thrs[clindex]);
605 	}
606 }
607 
608 /*
609  * Destroy a PFS, typically only occurs after the last mount on a device
610  * has gone away.
611  */
612 static void
613 hammer2_pfsfree(hammer2_pfs_t *pmp)
614 {
615 	hammer2_inode_t *iroot;
616 	hammer2_chain_t *chain;
617 	int i;
618 	int j;
619 
620 	/*
621 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
622 	 * by the flush code.
623 	 */
624 	TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
625 
626 	iroot = pmp->iroot;
627 	if (iroot) {
628 		for (i = 0; i < iroot->cluster.nchains; ++i) {
629 			hammer2_thr_delete(&pmp->sync_thrs[i]);
630 			for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
631 				hammer2_thr_delete(&pmp->xop_groups[j].thrs[i]);
632 		}
633 #if REPORT_REFS_ERRORS
634 		if (pmp->iroot->refs != 1)
635 			kprintf("PMP->IROOT %p REFS WRONG %d\n",
636 				pmp->iroot, pmp->iroot->refs);
637 #else
638 		KKASSERT(pmp->iroot->refs == 1);
639 #endif
640 		/* ref for pmp->iroot */
641 		hammer2_inode_drop(pmp->iroot);
642 		pmp->iroot = NULL;
643 	}
644 
645 	/*
646 	 * Cleanup chains remaining on LRU list.
647 	 */
648 	kprintf("pfsfree: %p lrucount=%d\n", pmp, pmp->lru_count);
649 	while ((chain = TAILQ_FIRST(&pmp->lru_list)) != NULL) {
650 		hammer2_chain_ref(chain);
651 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
652 		hammer2_chain_drop(chain);
653 	}
654 
655 	/*
656 	 * Free remaining pmp resources
657 	 */
658 	kmalloc_destroy(&pmp->mmsg);
659 	kmalloc_destroy(&pmp->minode);
660 
661 	kfree(pmp, M_HAMMER2);
662 }
663 
664 /*
665  * Remove all references to hmp from the pfs list.  Any PFS which becomes
666  * empty is terminated and freed.
667  *
668  * XXX inefficient.
669  */
670 static void
671 hammer2_pfsfree_scan(hammer2_dev_t *hmp)
672 {
673 	hammer2_pfs_t *pmp;
674 	hammer2_inode_t *iroot;
675 	hammer2_chain_t *rchain;
676 	int didfreeze;
677 	int i;
678 	int j;
679 
680 again:
681 	TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
682 		if ((iroot = pmp->iroot) == NULL)
683 			continue;
684 		if (hmp->spmp == pmp) {
685 			kprintf("unmount hmp %p remove spmp %p\n",
686 				hmp, pmp);
687 			hmp->spmp = NULL;
688 		}
689 
690 		/*
691 		 * Determine if this PFS is affected.  If it is we must
692 		 * freeze all management threads and lock its iroot.
693 		 *
694 		 * Freezing a management thread forces it idle, operations
695 		 * in-progress will be aborted and it will have to start
696 		 * over again when unfrozen, or exit if told to exit.
697 		 */
698 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
699 			if (pmp->pfs_hmps[i] == hmp)
700 				break;
701 		}
702 		if (i != HAMMER2_MAXCLUSTER) {
703 			/*
704 			 * Make sure all synchronization threads are locked
705 			 * down.
706 			 */
707 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
708 				if (pmp->pfs_hmps[i] == NULL)
709 					continue;
710 				hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
711 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
712 					hammer2_thr_freeze_async(
713 						&pmp->xop_groups[j].thrs[i]);
714 				}
715 			}
716 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
717 				if (pmp->pfs_hmps[i] == NULL)
718 					continue;
719 				hammer2_thr_freeze(&pmp->sync_thrs[i]);
720 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
721 					hammer2_thr_freeze(
722 						&pmp->xop_groups[j].thrs[i]);
723 				}
724 			}
725 
726 			/*
727 			 * Lock the inode and clean out matching chains.
728 			 * Note that we cannot use hammer2_inode_lock_*()
729 			 * here because that would attempt to validate the
730 			 * cluster that we are in the middle of ripping
731 			 * apart.
732 			 *
733 			 * WARNING! We are working directly on the inodes
734 			 *	    embedded cluster.
735 			 */
736 			hammer2_mtx_ex(&iroot->lock);
737 
738 			/*
739 			 * Remove the chain from matching elements of the PFS.
740 			 */
741 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
742 				if (pmp->pfs_hmps[i] != hmp)
743 					continue;
744 				hammer2_thr_delete(&pmp->sync_thrs[i]);
745 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
746 					hammer2_thr_delete(
747 						&pmp->xop_groups[j].thrs[i]);
748 				}
749 				rchain = iroot->cluster.array[i].chain;
750 				iroot->cluster.array[i].chain = NULL;
751 				pmp->pfs_types[i] = 0;
752 				if (pmp->pfs_names[i]) {
753 					kfree(pmp->pfs_names[i], M_HAMMER2);
754 					pmp->pfs_names[i] = NULL;
755 				}
756 				if (rchain) {
757 					hammer2_chain_drop(rchain);
758 					/* focus hint */
759 					if (iroot->cluster.focus == rchain)
760 						iroot->cluster.focus = NULL;
761 				}
762 				pmp->pfs_hmps[i] = NULL;
763 			}
764 			hammer2_mtx_unlock(&iroot->lock);
765 			didfreeze = 1;	/* remaster, unfreeze down below */
766 		} else {
767 			didfreeze = 0;
768 		}
769 
770 		/*
771 		 * Cleanup trailing chains.  Gaps may remain.
772 		 */
773 		for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
774 			if (pmp->pfs_hmps[i])
775 				break;
776 		}
777 		iroot->cluster.nchains = i + 1;
778 
779 		/*
780 		 * If the PMP has no elements remaining we can destroy it.
781 		 * (this will transition management threads from frozen->exit).
782 		 */
783 		if (iroot->cluster.nchains == 0) {
784 			kprintf("unmount hmp %p last ref to PMP=%p\n",
785 				hmp, pmp);
786 			hammer2_pfsfree(pmp);
787 			goto again;
788 		}
789 
790 		/*
791 		 * If elements still remain we need to set the REMASTER
792 		 * flag and unfreeze it.
793 		 */
794 		if (didfreeze) {
795 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
796 				if (pmp->pfs_hmps[i] == NULL)
797 					continue;
798 				hammer2_thr_remaster(&pmp->sync_thrs[i]);
799 				hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
800 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
801 					hammer2_thr_remaster(
802 						&pmp->xop_groups[j].thrs[i]);
803 					hammer2_thr_unfreeze(
804 						&pmp->xop_groups[j].thrs[i]);
805 				}
806 			}
807 		}
808 	}
809 }
810 
811 /*
812  * Mount or remount HAMMER2 fileystem from physical media
813  *
814  *	mountroot
815  *		mp		mount point structure
816  *		path		NULL
817  *		data		<unused>
818  *		cred		<unused>
819  *
820  *	mount
821  *		mp		mount point structure
822  *		path		path to mount point
823  *		data		pointer to argument structure in user space
824  *			volume	volume path (device@LABEL form)
825  *			hflags	user mount flags
826  *		cred		user credentials
827  *
828  * RETURNS:	0	Success
829  *		!0	error number
830  */
831 static
832 int
833 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
834 		  struct ucred *cred)
835 {
836 	struct hammer2_mount_info info;
837 	hammer2_pfs_t *pmp;
838 	hammer2_pfs_t *spmp;
839 	hammer2_dev_t *hmp;
840 	hammer2_dev_t *force_local;
841 	hammer2_key_t key_next;
842 	hammer2_key_t key_dummy;
843 	hammer2_key_t lhc;
844 	struct vnode *devvp;
845 	struct nlookupdata nd;
846 	hammer2_chain_t *parent;
847 	hammer2_chain_t *chain;
848 	hammer2_cluster_t *cluster;
849 	const hammer2_inode_data_t *ripdata;
850 	hammer2_blockref_t bref;
851 	struct file *fp;
852 	char devstr[MNAMELEN];
853 	size_t size;
854 	size_t done;
855 	char *dev;
856 	char *label;
857 	int ronly = 1;
858 	int error;
859 	int cache_index;
860 	int i;
861 
862 	hmp = NULL;
863 	pmp = NULL;
864 	dev = NULL;
865 	label = NULL;
866 	devvp = NULL;
867 	cache_index = -1;
868 
869 	kprintf("hammer2_mount\n");
870 
871 	if (path == NULL) {
872 		/*
873 		 * Root mount
874 		 */
875 		bzero(&info, sizeof(info));
876 		info.cluster_fd = -1;
877 		ksnprintf(devstr, sizeof(devstr), "%s",
878 			  mp->mnt_stat.f_mntfromname);
879 		kprintf("hammer2_mount: root '%s'\n", devstr);
880 	} else {
881 		/*
882 		 * Non-root mount or updating a mount
883 		 */
884 		error = copyin(data, &info, sizeof(info));
885 		if (error)
886 			return (error);
887 
888 		error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
889 		if (error)
890 			return (error);
891 	}
892 
893 	/*
894 	 * Extract device and label, automatically mount @LOCAL if no
895 	 * label specified.
896 	 */
897 	dev = devstr;
898 	label = strchr(devstr, '@');
899 	if (label && ((label + 1) - dev) > done)
900 		return (EINVAL);
901 	if (label == NULL || label[1] == 0) {
902 		label = "LOCAL";	/* not modified after this point */
903 	} else {
904 		*label = '\0';
905 		label++;
906 	}
907 
908 	kprintf("hammer2_mount: dev=\"%s\" label=\"%s\"\n",
909 		dev, label);
910 
911 	if (mp->mnt_flag & MNT_UPDATE) {
912 		/*
913 		 * Update mount.  Note that pmp->iroot->cluster is
914 		 * an inode-embedded cluster and thus cannot be
915 		 * directly locked.
916 		 *
917 		 * XXX HAMMER2 needs to implement NFS export via
918 		 *     mountctl.
919 		 */
920 		pmp = MPTOPMP(mp);
921 		pmp->hflags = info.hflags;
922 		cluster = &pmp->iroot->cluster;
923 		for (i = 0; i < cluster->nchains; ++i) {
924 			if (cluster->array[i].chain == NULL)
925 				continue;
926 			hmp = cluster->array[i].chain->hmp;
927 			devvp = hmp->devvp;
928 			error = hammer2_remount(hmp, mp, path,
929 						devvp, cred);
930 			if (error)
931 				break;
932 		}
933 
934 		return error;
935 	}
936 
937 	/*
938 	 * HMP device mount
939 	 *
940 	 * If a path is specified and dev is not an empty string, lookup the
941 	 * name and verify that it referes to a block device.
942 	 *
943 	 * If a path is specified and dev is an empty string we fall through
944 	 * and locate the label in the hmp search.
945 	 */
946 	if (path && *dev != 0) {
947 		error = nlookup_init(&nd, dev, UIO_SYSSPACE, NLC_FOLLOW);
948 		if (error == 0)
949 			error = nlookup(&nd);
950 		if (error == 0)
951 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
952 		nlookup_done(&nd);
953 	} else if (path == NULL) {
954 		/* root mount */
955 		cdev_t cdev = kgetdiskbyname(dev);
956 		error = bdevvp(cdev, &devvp);
957 		if (error)
958 			kprintf("hammer2: cannot find '%s'\n", dev);
959 	} else {
960 		/*
961 		 * We will locate the hmp using the label in the hmp loop.
962 		 */
963 		error = 0;
964 	}
965 
966 	if (error == 0 && devvp) {
967 		if (vn_isdisk(devvp, &error))
968 			error = vfs_mountedon(devvp);
969 	}
970 
971 	/*
972 	 * Determine if the device has already been mounted.  After this
973 	 * check hmp will be non-NULL if we are doing the second or more
974 	 * hammer2 mounts from the same device.
975 	 */
976 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
977 	if (devvp) {
978 		/*
979 		 * Match the device
980 		 */
981 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
982 			if (hmp->devvp == devvp)
983 				break;
984 		}
985 	} else if (error == 0) {
986 		/*
987 		 * Match the label to a pmp already probed.
988 		 */
989 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
990 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
991 				if (pmp->pfs_names[i] &&
992 				    strcmp(pmp->pfs_names[i], label) == 0) {
993 					hmp = pmp->pfs_hmps[i];
994 					break;
995 				}
996 			}
997 			if (hmp)
998 				break;
999 		}
1000 		if (hmp == NULL)
1001 			error = ENOENT;
1002 	}
1003 
1004 	/*
1005 	 * Open the device if this isn't a secondary mount and construct
1006 	 * the H2 device mount (hmp).
1007 	 */
1008 	if (hmp == NULL) {
1009 		hammer2_chain_t *schain;
1010 		hammer2_xid_t xid;
1011 
1012 		if (error == 0 && vcount(devvp) > 0)
1013 			error = EBUSY;
1014 
1015 		/*
1016 		 * Now open the device
1017 		 */
1018 		if (error == 0) {
1019 			ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
1020 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1021 			error = vinvalbuf(devvp, V_SAVE, 0, 0);
1022 			if (error == 0) {
1023 				error = VOP_OPEN(devvp,
1024 						 ronly ? FREAD : FREAD | FWRITE,
1025 						 FSCRED, NULL);
1026 			}
1027 			vn_unlock(devvp);
1028 		}
1029 		if (error && devvp) {
1030 			vrele(devvp);
1031 			devvp = NULL;
1032 		}
1033 		if (error) {
1034 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1035 			return error;
1036 		}
1037 		hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
1038 		ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
1039 		hmp->ronly = ronly;
1040 		hmp->devvp = devvp;
1041 		hmp->hflags = info.hflags & HMNT2_DEVFLAGS;
1042 		kmalloc_create(&hmp->mchain, "HAMMER2-chains");
1043 		TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
1044 		RB_INIT(&hmp->iotree);
1045 		spin_init(&hmp->io_spin, "hm2mount_io");
1046 		spin_init(&hmp->list_spin, "hm2mount_list");
1047 		TAILQ_INIT(&hmp->flushq);
1048 
1049 		lockinit(&hmp->vollk, "h2vol", 0, 0);
1050 		lockinit(&hmp->bulklk, "h2bulk", 0, 0);
1051 
1052 		/*
1053 		 * vchain setup. vchain.data is embedded.
1054 		 * vchain.refs is initialized and will never drop to 0.
1055 		 *
1056 		 * NOTE! voldata is not yet loaded.
1057 		 */
1058 		hmp->vchain.hmp = hmp;
1059 		hmp->vchain.refs = 1;
1060 		hmp->vchain.data = (void *)&hmp->voldata;
1061 		hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
1062 		hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1063 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1064 
1065 		hammer2_chain_core_init(&hmp->vchain);
1066 		/* hmp->vchain.u.xxx is left NULL */
1067 
1068 		/*
1069 		 * fchain setup.  fchain.data is embedded.
1070 		 * fchain.refs is initialized and will never drop to 0.
1071 		 *
1072 		 * The data is not used but needs to be initialized to
1073 		 * pass assertion muster.  We use this chain primarily
1074 		 * as a placeholder for the freemap's top-level RBTREE
1075 		 * so it does not interfere with the volume's topology
1076 		 * RBTREE.
1077 		 */
1078 		hmp->fchain.hmp = hmp;
1079 		hmp->fchain.refs = 1;
1080 		hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
1081 		hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
1082 		hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1083 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1084 		hmp->fchain.bref.methods =
1085 			HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
1086 			HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
1087 
1088 		hammer2_chain_core_init(&hmp->fchain);
1089 		/* hmp->fchain.u.xxx is left NULL */
1090 
1091 		/*
1092 		 * Install the volume header and initialize fields from
1093 		 * voldata.
1094 		 */
1095 		error = hammer2_install_volume_header(hmp);
1096 		if (error) {
1097 			hammer2_unmount_helper(mp, NULL, hmp);
1098 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1099 			hammer2_vfs_unmount(mp, MNT_FORCE);
1100 			return error;
1101 		}
1102 
1103 		/*
1104 		 * Really important to get these right or flush will get
1105 		 * confused.
1106 		 */
1107 		hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0, NULL);
1108 		kprintf("alloc spmp %p tid %016jx\n",
1109 			hmp->spmp, hmp->voldata.mirror_tid);
1110 		spmp = hmp->spmp;
1111 
1112 		/*
1113 		 * Dummy-up vchain and fchain's modify_tid.  mirror_tid
1114 		 * is inherited from the volume header.
1115 		 */
1116 		xid = 0;
1117 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1118 		hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
1119 		hmp->vchain.pmp = spmp;
1120 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1121 		hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
1122 		hmp->fchain.pmp = spmp;
1123 
1124 		/*
1125 		 * First locate the super-root inode, which is key 0
1126 		 * relative to the volume header's blockset.
1127 		 *
1128 		 * Then locate the root inode by scanning the directory keyspace
1129 		 * represented by the label.
1130 		 */
1131 		parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1132 		schain = hammer2_chain_lookup(&parent, &key_dummy,
1133 				      HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
1134 				      &cache_index, 0);
1135 		hammer2_chain_lookup_done(parent);
1136 		if (schain == NULL) {
1137 			kprintf("hammer2_mount: invalid super-root\n");
1138 			hammer2_unmount_helper(mp, NULL, hmp);
1139 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1140 			hammer2_vfs_unmount(mp, MNT_FORCE);
1141 			return EINVAL;
1142 		}
1143 		if (schain->error) {
1144 			kprintf("hammer2_mount: error %s reading super-root\n",
1145 				hammer2_error_str(schain->error));
1146 			hammer2_chain_unlock(schain);
1147 			hammer2_chain_drop(schain);
1148 			schain = NULL;
1149 			hammer2_unmount_helper(mp, NULL, hmp);
1150 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1151 			hammer2_vfs_unmount(mp, MNT_FORCE);
1152 			return EINVAL;
1153 		}
1154 
1155 		/*
1156 		 * The super-root always uses an inode_tid of 1 when
1157 		 * creating PFSs.
1158 		 */
1159 		spmp->inode_tid = 1;
1160 		spmp->modify_tid = schain->bref.modify_tid + 1;
1161 
1162 		/*
1163 		 * Sanity-check schain's pmp and finish initialization.
1164 		 * Any chain belonging to the super-root topology should
1165 		 * have a NULL pmp (not even set to spmp).
1166 		 */
1167 		ripdata = &hammer2_chain_rdata(schain)->ipdata;
1168 		KKASSERT(schain->pmp == NULL);
1169 		spmp->pfs_clid = ripdata->meta.pfs_clid;
1170 
1171 		/*
1172 		 * Replace the dummy spmp->iroot with a real one.  It's
1173 		 * easier to just do a wholesale replacement than to try
1174 		 * to update the chain and fixup the iroot fields.
1175 		 *
1176 		 * The returned inode is locked with the supplied cluster.
1177 		 */
1178 		cluster = hammer2_cluster_from_chain(schain);
1179 		hammer2_inode_drop(spmp->iroot);
1180 		spmp->iroot = NULL;
1181 		spmp->iroot = hammer2_inode_get(spmp, NULL, cluster, -1);
1182 		spmp->spmp_hmp = hmp;
1183 		spmp->pfs_types[0] = ripdata->meta.pfs_type;
1184 		spmp->pfs_hmps[0] = hmp;
1185 		hammer2_inode_ref(spmp->iroot);
1186 		hammer2_inode_unlock(spmp->iroot);
1187 		hammer2_cluster_unlock(cluster);
1188 		hammer2_cluster_drop(cluster);
1189 		schain = NULL;
1190 		/* leave spmp->iroot with one ref */
1191 
1192 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1193 			error = hammer2_recovery(hmp);
1194 			/* XXX do something with error */
1195 		}
1196 		hammer2_update_pmps(hmp);
1197 		hammer2_iocom_init(hmp);
1198 
1199 		/*
1200 		 * Ref the cluster management messaging descriptor.  The mount
1201 		 * program deals with the other end of the communications pipe.
1202 		 *
1203 		 * Root mounts typically do not supply one.
1204 		 */
1205 		if (info.cluster_fd >= 0) {
1206 			fp = holdfp(curproc->p_fd, info.cluster_fd, -1);
1207 			if (fp) {
1208 				hammer2_cluster_reconnect(hmp, fp);
1209 			} else {
1210 				kprintf("hammer2_mount: bad cluster_fd!\n");
1211 			}
1212 		}
1213 	} else {
1214 		spmp = hmp->spmp;
1215 		if (info.hflags & HMNT2_DEVFLAGS) {
1216 			kprintf("hammer2: Warning: mount flags pertaining "
1217 				"to the whole device may only be specified "
1218 				"on the first mount of the device: %08x\n",
1219 				info.hflags & HMNT2_DEVFLAGS);
1220 		}
1221 	}
1222 
1223 	/*
1224 	 * Force local mount (disassociate all PFSs from their clusters).
1225 	 * Used primarily for debugging.
1226 	 */
1227 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1228 
1229 	/*
1230 	 * Lookup the mount point under the media-localized super-root.
1231 	 * Scanning hammer2_pfslist doesn't help us because it represents
1232 	 * PFS cluster ids which can aggregate several named PFSs together.
1233 	 *
1234 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1235 	 * up later on.
1236 	 */
1237 	hammer2_inode_lock(spmp->iroot, 0);
1238 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1239 	lhc = hammer2_dirhash(label, strlen(label));
1240 	chain = hammer2_chain_lookup(&parent, &key_next,
1241 				     lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1242 				     &cache_index, 0);
1243 	while (chain) {
1244 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1245 		    strcmp(label, chain->data->ipdata.filename) == 0) {
1246 			break;
1247 		}
1248 		chain = hammer2_chain_next(&parent, chain, &key_next,
1249 					    key_next,
1250 					    lhc + HAMMER2_DIRHASH_LOMASK,
1251 					    &cache_index, 0);
1252 	}
1253 	if (parent) {
1254 		hammer2_chain_unlock(parent);
1255 		hammer2_chain_drop(parent);
1256 	}
1257 	hammer2_inode_unlock(spmp->iroot);
1258 
1259 	/*
1260 	 * PFS could not be found?
1261 	 */
1262 	if (chain == NULL) {
1263 		kprintf("hammer2_mount: PFS label not found\n");
1264 		hammer2_unmount_helper(mp, NULL, hmp);
1265 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1266 		hammer2_vfs_unmount(mp, MNT_FORCE);
1267 
1268 		return EINVAL;
1269 	}
1270 
1271 	/*
1272 	 * Acquire the pmp structure (it should have already been allocated
1273 	 * via hammer2_update_pmps() so do not pass cluster in to add to
1274 	 * available chains).
1275 	 *
1276 	 * Check if the cluster has already been mounted.  A cluster can
1277 	 * only be mounted once, use null mounts to mount additional copies.
1278 	 */
1279 	ripdata = &chain->data->ipdata;
1280 	bref = chain->bref;
1281 	pmp = hammer2_pfsalloc(NULL, ripdata,
1282 			       bref.modify_tid, force_local);
1283 	hammer2_chain_unlock(chain);
1284 	hammer2_chain_drop(chain);
1285 
1286 	/*
1287 	 * Finish the mount
1288 	 */
1289         kprintf("hammer2_mount hmp=%p pmp=%p\n", hmp, pmp);
1290 
1291 	if (pmp->mp) {
1292 		kprintf("hammer2_mount: PFS already mounted!\n");
1293 		hammer2_unmount_helper(mp, NULL, hmp);
1294 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1295 		hammer2_vfs_unmount(mp, MNT_FORCE);
1296 
1297 		return EBUSY;
1298 	}
1299 
1300 	pmp->hflags = info.hflags;
1301         mp->mnt_flag = MNT_LOCAL;
1302         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1303         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1304 
1305         /*
1306          * required mount structure initializations
1307          */
1308         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1309         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1310 
1311         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1312         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1313 
1314         /*
1315          * Optional fields
1316          */
1317         mp->mnt_iosize_max = MAXPHYS;
1318 
1319 	/*
1320 	 * Connect up mount pointers.
1321 	 */
1322 	hammer2_mount_helper(mp, pmp);
1323 
1324         lockmgr(&hammer2_mntlk, LK_RELEASE);
1325 
1326 	/*
1327 	 * Finish setup
1328 	 */
1329 	vfs_getnewfsid(mp);
1330 	vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1331 	vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1332 	vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1333 
1334 	if (path) {
1335 		copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1336 			  MNAMELEN - 1, &size);
1337 		bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1338 	} /* else root mount, already in there */
1339 
1340 	bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1341 	if (path) {
1342 		copyinstr(path, mp->mnt_stat.f_mntonname,
1343 			  sizeof(mp->mnt_stat.f_mntonname) - 1,
1344 			  &size);
1345 	} else {
1346 		/* root mount */
1347 		mp->mnt_stat.f_mntonname[0] = '/';
1348 	}
1349 
1350 	/*
1351 	 * Initial statfs to prime mnt_stat.
1352 	 */
1353 	hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1354 
1355 	return 0;
1356 }
1357 
1358 /*
1359  * Scan PFSs under the super-root and create hammer2_pfs structures.
1360  */
1361 static
1362 void
1363 hammer2_update_pmps(hammer2_dev_t *hmp)
1364 {
1365 	const hammer2_inode_data_t *ripdata;
1366 	hammer2_chain_t *parent;
1367 	hammer2_chain_t *chain;
1368 	hammer2_blockref_t bref;
1369 	hammer2_dev_t *force_local;
1370 	hammer2_pfs_t *spmp;
1371 	hammer2_pfs_t *pmp;
1372 	hammer2_key_t key_next;
1373 	int cache_index = -1;
1374 
1375 	/*
1376 	 * Force local mount (disassociate all PFSs from their clusters).
1377 	 * Used primarily for debugging.
1378 	 */
1379 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1380 
1381 	/*
1382 	 * Lookup mount point under the media-localized super-root.
1383 	 *
1384 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1385 	 * up later on.
1386 	 */
1387 	spmp = hmp->spmp;
1388 	hammer2_inode_lock(spmp->iroot, 0);
1389 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1390 	chain = hammer2_chain_lookup(&parent, &key_next,
1391 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1392 					 &cache_index, 0);
1393 	while (chain) {
1394 		if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
1395 			continue;
1396 		ripdata = &chain->data->ipdata;
1397 		bref = chain->bref;
1398 		kprintf("ADD LOCAL PFS: %s\n", ripdata->filename);
1399 
1400 		pmp = hammer2_pfsalloc(chain, ripdata,
1401 				       bref.modify_tid, force_local);
1402 		chain = hammer2_chain_next(&parent, chain, &key_next,
1403 					   key_next, HAMMER2_KEY_MAX,
1404 					   &cache_index, 0);
1405 	}
1406 	if (parent) {
1407 		hammer2_chain_unlock(parent);
1408 		hammer2_chain_drop(parent);
1409 	}
1410 	hammer2_inode_unlock(spmp->iroot);
1411 }
1412 
1413 static
1414 int
1415 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1416 		struct vnode *devvp, struct ucred *cred)
1417 {
1418 	int error;
1419 
1420 	if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
1421 		error = hammer2_recovery(hmp);
1422 	} else {
1423 		error = 0;
1424 	}
1425 	return error;
1426 }
1427 
1428 static
1429 int
1430 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1431 {
1432 	hammer2_pfs_t *pmp;
1433 	int flags;
1434 	int error = 0;
1435 
1436 	pmp = MPTOPMP(mp);
1437 
1438 	if (pmp == NULL)
1439 		return(0);
1440 
1441 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1442 
1443 	/*
1444 	 * If mount initialization proceeded far enough we must flush
1445 	 * its vnodes and sync the underlying mount points.  Three syncs
1446 	 * are required to fully flush the filesystem (freemap updates lag
1447 	 * by one flush, and one extra for safety).
1448 	 */
1449 	if (mntflags & MNT_FORCE)
1450 		flags = FORCECLOSE;
1451 	else
1452 		flags = 0;
1453 	if (pmp->iroot) {
1454 		error = vflush(mp, 0, flags);
1455 		if (error)
1456 			goto failed;
1457 		hammer2_vfs_sync(mp, MNT_WAIT);
1458 		hammer2_vfs_sync(mp, MNT_WAIT);
1459 		hammer2_vfs_sync(mp, MNT_WAIT);
1460 	}
1461 
1462 	/*
1463 	 * Cleanup the frontend support XOPS threads
1464 	 */
1465 	hammer2_xop_helper_cleanup(pmp);
1466 
1467 	if (pmp->mp)
1468 		hammer2_unmount_helper(mp, pmp, NULL);
1469 
1470 	error = 0;
1471 failed:
1472 	lockmgr(&hammer2_mntlk, LK_RELEASE);
1473 
1474 	return (error);
1475 }
1476 
1477 /*
1478  * Mount helper, hook the system mount into our PFS.
1479  * The mount lock is held.
1480  *
1481  * We must bump the mount_count on related devices for any
1482  * mounted PFSs.
1483  */
1484 static
1485 void
1486 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1487 {
1488 	hammer2_cluster_t *cluster;
1489 	hammer2_chain_t *rchain;
1490 	int i;
1491 
1492         mp->mnt_data = (qaddr_t)pmp;
1493 	pmp->mp = mp;
1494 
1495 	/*
1496 	 * After pmp->mp is set we have to adjust hmp->mount_count.
1497 	 */
1498 	cluster = &pmp->iroot->cluster;
1499 	for (i = 0; i < cluster->nchains; ++i) {
1500 		rchain = cluster->array[i].chain;
1501 		if (rchain == NULL)
1502 			continue;
1503 		++rchain->hmp->mount_count;
1504 		kprintf("hammer2_mount hmp=%p ++mount_count=%d\n",
1505 			rchain->hmp, rchain->hmp->mount_count);
1506 	}
1507 
1508 	/*
1509 	 * Create missing Xop threads
1510 	 */
1511 	hammer2_xop_helper_create(pmp);
1512 }
1513 
1514 /*
1515  * Mount helper, unhook the system mount from our PFS.
1516  * The mount lock is held.
1517  *
1518  * If hmp is supplied a mount responsible for being the first to open
1519  * the block device failed and the block device and all PFSs using the
1520  * block device must be cleaned up.
1521  *
1522  * If pmp is supplied multiple devices might be backing the PFS and each
1523  * must be disconnected.  This might not be the last PFS using some of the
1524  * underlying devices.  Also, we have to adjust our hmp->mount_count
1525  * accounting for the devices backing the pmp which is now undergoing an
1526  * unmount.
1527  */
1528 static
1529 void
1530 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1531 {
1532 	hammer2_cluster_t *cluster;
1533 	hammer2_chain_t *rchain;
1534 	struct vnode *devvp;
1535 	int dumpcnt;
1536 	int ronly = 0;
1537 	int i;
1538 
1539 	/*
1540 	 * If no device supplied this is a high-level unmount and we have to
1541 	 * to disconnect the mount, adjust mount_count, and locate devices
1542 	 * that might now have no mounts.
1543 	 */
1544 	if (pmp) {
1545 		KKASSERT(hmp == NULL);
1546 		KKASSERT((void *)(intptr_t)mp->mnt_data == pmp);
1547 		pmp->mp = NULL;
1548 		mp->mnt_data = NULL;
1549 
1550 		/*
1551 		 * After pmp->mp is cleared we have to account for
1552 		 * mount_count.
1553 		 */
1554 		cluster = &pmp->iroot->cluster;
1555 		for (i = 0; i < cluster->nchains; ++i) {
1556 			rchain = cluster->array[i].chain;
1557 			if (rchain == NULL)
1558 				continue;
1559 			--rchain->hmp->mount_count;
1560 			kprintf("hammer2_unmount hmp=%p --mount_count=%d\n",
1561 				rchain->hmp, rchain->hmp->mount_count);
1562 			/* scrapping hmp now may invalidate the pmp */
1563 		}
1564 again:
1565 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1566 			if (hmp->mount_count == 0) {
1567 				hammer2_unmount_helper(NULL, NULL, hmp);
1568 				goto again;
1569 			}
1570 		}
1571 		return;
1572 	}
1573 
1574 	/*
1575 	 * Try to terminate the block device.  We can't terminate it if
1576 	 * there are still PFSs referencing it.
1577 	 */
1578 	kprintf("hammer2_unmount hmp=%p mount_count=%d\n",
1579 		hmp, hmp->mount_count);
1580 	if (hmp->mount_count)
1581 		return;
1582 
1583 	hammer2_pfsfree_scan(hmp);
1584 	hammer2_dev_exlock(hmp);	/* XXX order */
1585 
1586 	/*
1587 	 * Cycle the volume data lock as a safety (probably not needed any
1588 	 * more).  To ensure everything is out we need to flush at least
1589 	 * three times.  (1) The running of the sideq can dirty the
1590 	 * filesystem, (2) A normal flush can dirty the freemap, and
1591 	 * (3) ensure that the freemap is fully synchronized.
1592 	 *
1593 	 * The next mount's recovery scan can clean everything up but we want
1594 	 * to leave the filesystem in a 100% clean state on a normal unmount.
1595 	 */
1596 #if 0
1597 	hammer2_voldata_lock(hmp);
1598 	hammer2_voldata_unlock(hmp);
1599 #endif
1600 	hammer2_iocom_uninit(hmp);
1601 
1602 	if ((hmp->vchain.flags | hmp->fchain.flags) &
1603 	    HAMMER2_CHAIN_FLUSH_MASK) {
1604 		kprintf("hammer2_unmount: chains left over "
1605 			"after final sync\n");
1606 		kprintf("    vchain %08x\n", hmp->vchain.flags);
1607 		kprintf("    fchain %08x\n", hmp->fchain.flags);
1608 
1609 		if (hammer2_debug & 0x0010)
1610 			Debugger("entered debugger");
1611 	}
1612 
1613 	KKASSERT(hmp->spmp == NULL);
1614 
1615 	/*
1616 	 * Finish up with the device vnode
1617 	 */
1618 	if ((devvp = hmp->devvp) != NULL) {
1619 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1620 		vinvalbuf(devvp, (ronly ? 0 : V_SAVE), 0, 0);
1621 		hmp->devvp = NULL;
1622 		VOP_CLOSE(devvp, (ronly ? FREAD : FREAD|FWRITE), NULL);
1623 		vn_unlock(devvp);
1624 		vrele(devvp);
1625 		devvp = NULL;
1626 	}
1627 
1628 	/*
1629 	 * Clear vchain/fchain flags that might prevent final cleanup
1630 	 * of these chains.
1631 	 */
1632 	if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1633 		atomic_add_long(&hammer2_count_modified_chains, -1);
1634 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1635 		hammer2_pfs_memory_wakeup(hmp->vchain.pmp);
1636 	}
1637 	if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1638 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_UPDATE);
1639 	}
1640 
1641 	if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1642 		atomic_add_long(&hammer2_count_modified_chains, -1);
1643 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_MODIFIED);
1644 		hammer2_pfs_memory_wakeup(hmp->fchain.pmp);
1645 	}
1646 	if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1647 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_UPDATE);
1648 	}
1649 
1650 	/*
1651 	 * Final drop of embedded freemap root chain to
1652 	 * clean up fchain.core (fchain structure is not
1653 	 * flagged ALLOCATED so it is cleaned out and then
1654 	 * left to rot).
1655 	 */
1656 	hammer2_chain_drop(&hmp->fchain);
1657 
1658 	/*
1659 	 * Final drop of embedded volume root chain to clean
1660 	 * up vchain.core (vchain structure is not flagged
1661 	 * ALLOCATED so it is cleaned out and then left to
1662 	 * rot).
1663 	 */
1664 	dumpcnt = 50;
1665 	hammer2_dump_chain(&hmp->vchain, 0, &dumpcnt, 'v');
1666 	dumpcnt = 50;
1667 	hammer2_dump_chain(&hmp->fchain, 0, &dumpcnt, 'f');
1668 	hammer2_dev_unlock(hmp);
1669 	hammer2_chain_drop(&hmp->vchain);
1670 
1671 	hammer2_io_cleanup(hmp, &hmp->iotree);
1672 	if (hmp->iofree_count) {
1673 		kprintf("io_cleanup: %d I/O's left hanging\n",
1674 			hmp->iofree_count);
1675 	}
1676 
1677 	TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1678 	kmalloc_destroy(&hmp->mchain);
1679 	kfree(hmp, M_HAMMER2);
1680 }
1681 
1682 int
1683 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1684 		 ino_t ino, struct vnode **vpp)
1685 {
1686 	hammer2_xop_lookup_t *xop;
1687 	hammer2_pfs_t *pmp;
1688 	hammer2_inode_t *ip;
1689 	hammer2_tid_t inum;
1690 	int error;
1691 
1692 	inum = (hammer2_tid_t)ino & HAMMER2_DIRHASH_USERMSK;
1693 
1694 	error = 0;
1695 	pmp = MPTOPMP(mp);
1696 
1697 	/*
1698 	 * Easy if we already have it cached
1699 	 */
1700 	ip = hammer2_inode_lookup(pmp, inum);
1701 	if (ip) {
1702 		hammer2_inode_lock(ip, HAMMER2_RESOLVE_SHARED);
1703 		*vpp = hammer2_igetv(ip, &error);
1704 		hammer2_inode_unlock(ip);
1705 		hammer2_inode_drop(ip);		/* from lookup */
1706 
1707 		return error;
1708 	}
1709 
1710 	/*
1711 	 * Otherwise we have to find the inode
1712 	 */
1713 	xop = hammer2_xop_alloc(pmp->iroot, 0);
1714 	xop->lhc = inum;
1715 	hammer2_xop_start(&xop->head, hammer2_xop_lookup);
1716 	error = hammer2_xop_collect(&xop->head, 0);
1717 
1718 	if (error == 0) {
1719 		if (hammer2_cluster_rdata(&xop->head.cluster) == NULL) {
1720 			kprintf("vget: no collect error but also no rdata\n");
1721 			kprintf("xop %p\n", xop);
1722 			while ((hammer2_debug & 0x80000) == 0) {
1723 				tsleep(xop, PCATCH, "wait", hz * 10);
1724 			}
1725 			ip = NULL;
1726 		} else {
1727 			ip = hammer2_inode_get(pmp, NULL, &xop->head.cluster, -1);
1728 		}
1729 	}
1730 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1731 
1732 	if (ip) {
1733 		*vpp = hammer2_igetv(ip, &error);
1734 		hammer2_inode_unlock(ip);
1735 	} else {
1736 		*vpp = NULL;
1737 		error = ENOENT;
1738 	}
1739 	return (error);
1740 }
1741 
1742 static
1743 int
1744 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1745 {
1746 	hammer2_pfs_t *pmp;
1747 	struct vnode *vp;
1748 	int error;
1749 
1750 	pmp = MPTOPMP(mp);
1751 	if (pmp->iroot == NULL) {
1752 		*vpp = NULL;
1753 		return EINVAL;
1754 	}
1755 
1756 	error = 0;
1757 	hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1758 
1759 	while (pmp->inode_tid == 0) {
1760 		hammer2_xop_ipcluster_t *xop;
1761 		hammer2_inode_meta_t *meta;
1762 
1763 		xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1764 		hammer2_xop_start(&xop->head, hammer2_xop_ipcluster);
1765 		error = hammer2_xop_collect(&xop->head, 0);
1766 
1767 		if (error == 0) {
1768 			meta = &xop->head.cluster.focus->data->ipdata.meta;
1769 			pmp->iroot->meta = *meta;
1770 			pmp->inode_tid = meta->pfs_inum + 1;
1771 			if (pmp->inode_tid < HAMMER2_INODE_START)
1772 				pmp->inode_tid = HAMMER2_INODE_START;
1773 			pmp->modify_tid =
1774 				xop->head.cluster.focus->bref.modify_tid + 1;
1775 			kprintf("PFS: Starting inode %jd\n",
1776 				(intmax_t)pmp->inode_tid);
1777 			kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1778 				pmp->inode_tid, pmp->modify_tid);
1779 			wakeup(&pmp->iroot);
1780 
1781 			hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1782 
1783 			/*
1784 			 * Prime the mount info.
1785 			 */
1786 			hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
1787 			break;
1788 		}
1789 
1790 		/*
1791 		 * Loop, try again
1792 		 */
1793 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1794 		hammer2_inode_unlock(pmp->iroot);
1795 		error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
1796 		hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1797 		if (error == EINTR)
1798 			break;
1799 	}
1800 
1801 	if (error) {
1802 		hammer2_inode_unlock(pmp->iroot);
1803 		*vpp = NULL;
1804 	} else {
1805 		vp = hammer2_igetv(pmp->iroot, &error);
1806 		hammer2_inode_unlock(pmp->iroot);
1807 		*vpp = vp;
1808 	}
1809 
1810 	return (error);
1811 }
1812 
1813 /*
1814  * Filesystem status
1815  *
1816  * XXX incorporate ipdata->meta.inode_quota and data_quota
1817  */
1818 static
1819 int
1820 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
1821 {
1822 	hammer2_pfs_t *pmp;
1823 	hammer2_dev_t *hmp;
1824 	hammer2_blockref_t bref;
1825 	int i;
1826 
1827 	/*
1828 	 * NOTE: iroot might not have validated the cluster yet.
1829 	 */
1830 	pmp = MPTOPMP(mp);
1831 
1832 	mp->mnt_stat.f_files = 0;
1833 	mp->mnt_stat.f_ffree = 0;
1834 	mp->mnt_stat.f_blocks = 0;
1835 	mp->mnt_stat.f_bfree = 0;
1836 	mp->mnt_stat.f_bavail = 0;
1837 
1838 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1839 		hmp = pmp->pfs_hmps[i];
1840 		if (hmp == NULL)
1841 			continue;
1842 		if (pmp->iroot->cluster.array[i].chain)
1843 			bref = pmp->iroot->cluster.array[i].chain->bref;
1844 		else
1845 			bzero(&bref, sizeof(bref));
1846 
1847 		mp->mnt_stat.f_files = bref.embed.stats.inode_count;
1848 		mp->mnt_stat.f_ffree = 0;
1849 		mp->mnt_stat.f_blocks = hmp->voldata.allocator_size /
1850 					mp->mnt_vstat.f_bsize;
1851 		mp->mnt_stat.f_bfree = hmp->voldata.allocator_free /
1852 					mp->mnt_vstat.f_bsize;
1853 		mp->mnt_stat.f_bavail = mp->mnt_stat.f_bfree;
1854 
1855 		*sbp = mp->mnt_stat;
1856 	}
1857 	return (0);
1858 }
1859 
1860 static
1861 int
1862 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
1863 {
1864 	hammer2_pfs_t *pmp;
1865 	hammer2_dev_t *hmp;
1866 	hammer2_blockref_t bref;
1867 	int i;
1868 
1869 	/*
1870 	 * NOTE: iroot might not have validated the cluster yet.
1871 	 */
1872 	pmp = MPTOPMP(mp);
1873 
1874 	mp->mnt_vstat.f_bsize = 0;
1875 	mp->mnt_vstat.f_files = 0;
1876 	mp->mnt_vstat.f_ffree = 0;
1877 	mp->mnt_vstat.f_blocks = 0;
1878 	mp->mnt_vstat.f_bfree = 0;
1879 	mp->mnt_vstat.f_bavail = 0;
1880 
1881 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1882 		hmp = pmp->pfs_hmps[i];
1883 		if (hmp == NULL)
1884 			continue;
1885 		if (pmp->iroot->cluster.array[i].chain)
1886 			bref = pmp->iroot->cluster.array[i].chain->bref;
1887 		else
1888 			bzero(&bref, sizeof(bref));
1889 
1890 		mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1891 		mp->mnt_vstat.f_files = bref.embed.stats.inode_count;
1892 		mp->mnt_vstat.f_ffree = 0;
1893 		mp->mnt_vstat.f_blocks = hmp->voldata.allocator_size /
1894 					mp->mnt_vstat.f_bsize;
1895 		mp->mnt_vstat.f_bfree = hmp->voldata.allocator_free /
1896 					mp->mnt_vstat.f_bsize;
1897 		mp->mnt_vstat.f_bavail = mp->mnt_vstat.f_bfree;
1898 
1899 		*sbp = mp->mnt_vstat;
1900 	}
1901 	return (0);
1902 }
1903 
1904 /*
1905  * Mount-time recovery (RW mounts)
1906  *
1907  * Updates to the free block table are allowed to lag flushes by one
1908  * transaction.  In case of a crash, then on a fresh mount we must do an
1909  * incremental scan of the last committed transaction id and make sure that
1910  * all related blocks have been marked allocated.
1911  *
1912  * The super-root topology and each PFS has its own transaction id domain,
1913  * so we must track PFS boundary transitions.
1914  */
1915 struct hammer2_recovery_elm {
1916 	TAILQ_ENTRY(hammer2_recovery_elm) entry;
1917 	hammer2_chain_t *chain;
1918 	hammer2_tid_t sync_tid;
1919 };
1920 
1921 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
1922 
1923 struct hammer2_recovery_info {
1924 	struct hammer2_recovery_list list;
1925 	hammer2_tid_t	mtid;
1926 	int	depth;
1927 };
1928 
1929 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
1930 			hammer2_chain_t *parent,
1931 			struct hammer2_recovery_info *info,
1932 			hammer2_tid_t sync_tid);
1933 
1934 #define HAMMER2_RECOVERY_MAXDEPTH	10
1935 
1936 static
1937 int
1938 hammer2_recovery(hammer2_dev_t *hmp)
1939 {
1940 	struct hammer2_recovery_info info;
1941 	struct hammer2_recovery_elm *elm;
1942 	hammer2_chain_t *parent;
1943 	hammer2_tid_t sync_tid;
1944 	hammer2_tid_t mirror_tid;
1945 	int error;
1946 	int cumulative_error = 0;
1947 
1948 	hammer2_trans_init(hmp->spmp, 0);
1949 
1950 	sync_tid = hmp->voldata.freemap_tid;
1951 	mirror_tid = hmp->voldata.mirror_tid;
1952 
1953 	kprintf("hammer2 mount \"%s\": ", hmp->devrepname);
1954 	if (sync_tid >= mirror_tid) {
1955 		kprintf(" no recovery needed\n");
1956 	} else {
1957 		kprintf(" freemap recovery %016jx-%016jx\n",
1958 			sync_tid + 1, mirror_tid);
1959 	}
1960 
1961 	TAILQ_INIT(&info.list);
1962 	info.depth = 0;
1963 	parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1964 	cumulative_error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
1965 	hammer2_chain_lookup_done(parent);
1966 
1967 	while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
1968 		TAILQ_REMOVE(&info.list, elm, entry);
1969 		parent = elm->chain;
1970 		sync_tid = elm->sync_tid;
1971 		kfree(elm, M_HAMMER2);
1972 
1973 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1974 		error = hammer2_recovery_scan(hmp, parent, &info,
1975 					      hmp->voldata.freemap_tid);
1976 		hammer2_chain_unlock(parent);
1977 		hammer2_chain_drop(parent);	/* drop elm->chain ref */
1978 		if (error)
1979 			cumulative_error = error;
1980 	}
1981 	hammer2_trans_done(hmp->spmp);
1982 
1983 	return cumulative_error;
1984 }
1985 
1986 static
1987 int
1988 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
1989 		      struct hammer2_recovery_info *info,
1990 		      hammer2_tid_t sync_tid)
1991 {
1992 	const hammer2_inode_data_t *ripdata;
1993 	hammer2_chain_t *chain;
1994 	hammer2_blockref_t bref;
1995 	int cache_index;
1996 	int cumulative_error = 0;
1997 	int error;
1998 	int first;
1999 
2000 	/*
2001 	 * Adjust freemap to ensure that the block(s) are marked allocated.
2002 	 */
2003 	if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
2004 		hammer2_freemap_adjust(hmp, &parent->bref,
2005 				       HAMMER2_FREEMAP_DORECOVER);
2006 	}
2007 
2008 	/*
2009 	 * Check type for recursive scan
2010 	 */
2011 	switch(parent->bref.type) {
2012 	case HAMMER2_BREF_TYPE_VOLUME:
2013 		/* data already instantiated */
2014 		break;
2015 	case HAMMER2_BREF_TYPE_INODE:
2016 		/*
2017 		 * Must instantiate data for DIRECTDATA test and also
2018 		 * for recursion.
2019 		 */
2020 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2021 		ripdata = &hammer2_chain_rdata(parent)->ipdata;
2022 		if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
2023 			/* not applicable to recovery scan */
2024 			hammer2_chain_unlock(parent);
2025 			return 0;
2026 		}
2027 		hammer2_chain_unlock(parent);
2028 		break;
2029 	case HAMMER2_BREF_TYPE_INDIRECT:
2030 		/*
2031 		 * Must instantiate data for recursion
2032 		 */
2033 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2034 		hammer2_chain_unlock(parent);
2035 		break;
2036 	case HAMMER2_BREF_TYPE_DIRENT:
2037 	case HAMMER2_BREF_TYPE_DATA:
2038 	case HAMMER2_BREF_TYPE_FREEMAP:
2039 	case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2040 	case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2041 		/* not applicable to recovery scan */
2042 		return 0;
2043 		break;
2044 	default:
2045 		return EDOM;
2046 	}
2047 
2048 	/*
2049 	 * Defer operation if depth limit reached or if we are crossing a
2050 	 * PFS boundary.
2051 	 */
2052 	if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
2053 		struct hammer2_recovery_elm *elm;
2054 
2055 		elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
2056 		elm->chain = parent;
2057 		elm->sync_tid = sync_tid;
2058 		hammer2_chain_ref(parent);
2059 		TAILQ_INSERT_TAIL(&info->list, elm, entry);
2060 		/* unlocked by caller */
2061 
2062 		return(0);
2063 	}
2064 
2065 
2066 	/*
2067 	 * Recursive scan of the last flushed transaction only.  We are
2068 	 * doing this without pmp assignments so don't leave the chains
2069 	 * hanging around after we are done with them.
2070 	 */
2071 	cache_index = 0;
2072 	chain = NULL;
2073 	first = 1;
2074 
2075 	while (hammer2_chain_scan(parent, &chain, &bref,
2076 				  &first, &cache_index,
2077 				  HAMMER2_LOOKUP_NODATA) != NULL) {
2078 		/*
2079 		 * If this is a leaf
2080 		 */
2081 		if (chain == NULL) {
2082 			if (bref.mirror_tid > sync_tid) {
2083 				hammer2_freemap_adjust(hmp, &bref,
2084 						     HAMMER2_FREEMAP_DORECOVER);
2085 			}
2086 			continue;
2087 		}
2088 
2089 		/*
2090 		 * This may or may not be a recursive node.
2091 		 */
2092 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
2093 		if (bref.mirror_tid > sync_tid) {
2094 			++info->depth;
2095 			error = hammer2_recovery_scan(hmp, chain,
2096 						      info, sync_tid);
2097 			--info->depth;
2098 			if (error)
2099 				cumulative_error = error;
2100 		}
2101 
2102 		/*
2103 		 * Flush the recovery at the PFS boundary to stage it for
2104 		 * the final flush of the super-root topology.
2105 		 */
2106 		if ((bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
2107 		    (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
2108 			hammer2_flush(chain, HAMMER2_FLUSH_TOP);
2109 		}
2110 	}
2111 
2112 	return cumulative_error;
2113 }
2114 
2115 /*
2116  * Sync a mount point; this is called on a per-mount basis from the
2117  * filesystem syncer process periodically and whenever a user issues
2118  * a sync.
2119  */
2120 int
2121 hammer2_vfs_sync(struct mount *mp, int waitfor)
2122 {
2123 	hammer2_xop_flush_t *xop;
2124 	struct hammer2_sync_info info;
2125 	hammer2_inode_t *iroot;
2126 	hammer2_pfs_t *pmp;
2127 	int flags;
2128 	int error;
2129 
2130 	pmp = MPTOPMP(mp);
2131 	iroot = pmp->iroot;
2132 	KKASSERT(iroot);
2133 	KKASSERT(iroot->pmp == pmp);
2134 
2135 	/*
2136 	 * We can't acquire locks on existing vnodes while in a transaction
2137 	 * without risking a deadlock.  This assumes that vfsync() can be
2138 	 * called without the vnode locked (which it can in DragonFly).
2139 	 * Otherwise we'd have to implement a multi-pass or flag the lock
2140 	 * failures and retry.
2141 	 *
2142 	 * The reclamation code interlocks with the sync list's token
2143 	 * (by removing the vnode from the scan list) before unlocking
2144 	 * the inode, giving us time to ref the inode.
2145 	 */
2146 	/*flags = VMSC_GETVP;*/
2147 	flags = 0;
2148 	if (waitfor & MNT_LAZY)
2149 		flags |= VMSC_ONEPASS;
2150 
2151 	/*
2152 	 * Preflush the vnodes using a normal transaction before interlocking
2153 	 * with a flush transaction.  We do this to try to run as much of
2154 	 * the compression as possible outside the flush transaction.
2155 	 *
2156 	 * For efficiency do an async pass before making sure with a
2157 	 * synchronous pass on all related buffer cache buffers.
2158 	 */
2159 	hammer2_trans_init(pmp, 0);
2160 	info.error = 0;
2161 	info.waitfor = MNT_NOWAIT;
2162 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2163 	info.waitfor = MNT_WAIT;
2164 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2165 	hammer2_trans_done(pmp);
2166 
2167 	/*
2168 	 * Start our flush transaction.  This does not return until all
2169 	 * concurrent transactions have completed and will prevent any
2170 	 * new transactions from running concurrently, except for the
2171 	 * buffer cache transactions.
2172 	 *
2173 	 * NOTE!  It is still possible for the paging code to push pages
2174 	 *	  out via a UIO_NOCOPY hammer2_vop_write() during the main
2175 	 *	  flush.
2176 	 */
2177 	hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
2178 	hammer2_inode_run_sideq(pmp);
2179 
2180 	info.error = 0;
2181 	info.waitfor = MNT_NOWAIT;
2182 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2183 	info.waitfor = MNT_WAIT;
2184 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2185 	hammer2_bioq_sync(pmp);
2186 
2187 	/*
2188 	 * Use the XOP interface to concurrently flush all nodes to
2189 	 * synchronize the PFSROOT subtopology to the media.  A standard
2190 	 * end-of-scan ENOENT error indicates cluster sufficiency.
2191 	 *
2192 	 * Note that this flush will not be visible on crash recovery until
2193 	 * we flush the super-root topology in the next loop.
2194 	 *
2195 	 * XXX For now wait for all flushes to complete.
2196 	 */
2197 	if (iroot) {
2198 		xop = hammer2_xop_alloc(iroot, HAMMER2_XOP_MODIFYING);
2199 		hammer2_xop_start(&xop->head, hammer2_inode_xop_flush);
2200 		error = hammer2_xop_collect(&xop->head,
2201 					    HAMMER2_XOP_COLLECT_WAITALL);
2202 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2203 		if (error == ENOENT)
2204 			error = 0;
2205 	} else {
2206 		error = 0;
2207 	}
2208 	hammer2_trans_done(pmp);
2209 
2210 	return (error);
2211 }
2212 
2213 /*
2214  * Sync passes.
2215  *
2216  * Note that we ignore the tranasction mtid we got above.  Instead,
2217  * each vfsync below will ultimately get its own via TRANS_BUFCACHE
2218  * transactions.
2219  */
2220 static int
2221 hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
2222 {
2223 	struct hammer2_sync_info *info = data;
2224 	hammer2_inode_t *ip;
2225 	int error;
2226 
2227 	/*
2228 	 * Degenerate cases.  Note that ip == NULL typically means the
2229 	 * syncer vnode itself and we don't want to vclrisdirty() in that
2230 	 * situation.
2231 	 */
2232 	ip = VTOI(vp);
2233 	if (ip == NULL) {
2234 		return(0);
2235 	}
2236 	if (vp->v_type == VNON || vp->v_type == VBAD) {
2237 		vclrisdirty(vp);
2238 		return(0);
2239 	}
2240 
2241 	/*
2242 	 * VOP_FSYNC will start a new transaction so replicate some code
2243 	 * here to do it inline (see hammer2_vop_fsync()).
2244 	 *
2245 	 * WARNING: The vfsync interacts with the buffer cache and might
2246 	 *          block, we can't hold the inode lock at that time.
2247 	 *	    However, we MUST ref ip before blocking to ensure that
2248 	 *	    it isn't ripped out from under us (since we do not
2249 	 *	    hold a lock on the vnode).
2250 	 */
2251 	hammer2_inode_ref(ip);
2252 	if ((ip->flags & HAMMER2_INODE_MODIFIED) ||
2253 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
2254 		vfsync(vp, info->waitfor, 1, NULL, NULL);
2255 		if (ip->flags & (HAMMER2_INODE_RESIZED |
2256 				 HAMMER2_INODE_MODIFIED)) {
2257 			hammer2_inode_lock(ip, 0);
2258 			hammer2_inode_chain_sync(ip);
2259 			hammer2_inode_unlock(ip);
2260 		}
2261 	}
2262 	if ((ip->flags & HAMMER2_INODE_MODIFIED) == 0 &&
2263 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
2264 		vclrisdirty(vp);
2265 	}
2266 
2267 	hammer2_inode_drop(ip);
2268 #if 1
2269 	error = 0;
2270 	if (error)
2271 		info->error = error;
2272 #endif
2273 	return(0);
2274 }
2275 
2276 static
2277 int
2278 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2279 {
2280 	hammer2_inode_t *ip;
2281 
2282 	KKASSERT(MAXFIDSZ >= 16);
2283 	ip = VTOI(vp);
2284 	fhp->fid_len = offsetof(struct fid, fid_data[16]);
2285 	fhp->fid_ext = 0;
2286 	((hammer2_tid_t *)fhp->fid_data)[0] = ip->meta.inum;
2287 	((hammer2_tid_t *)fhp->fid_data)[1] = 0;
2288 
2289 	return 0;
2290 }
2291 
2292 static
2293 int
2294 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2295 	       struct fid *fhp, struct vnode **vpp)
2296 {
2297 	hammer2_pfs_t *pmp;
2298 	hammer2_tid_t inum;
2299 	int error;
2300 
2301 	pmp = MPTOPMP(mp);
2302 	inum = ((hammer2_tid_t *)fhp->fid_data)[0] & HAMMER2_DIRHASH_USERMSK;
2303 	if (vpp) {
2304 		if (inum == 1)
2305 			error = hammer2_vfs_root(mp, vpp);
2306 		else
2307 			error = hammer2_vfs_vget(mp, NULL, inum, vpp);
2308 	} else {
2309 		error = 0;
2310 	}
2311 	if (error)
2312 		kprintf("fhtovp: %016jx -> %p, %d\n", inum, *vpp, error);
2313 	return error;
2314 }
2315 
2316 static
2317 int
2318 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2319 		 int *exflagsp, struct ucred **credanonp)
2320 {
2321 	hammer2_pfs_t *pmp;
2322 	struct netcred *np;
2323 	int error;
2324 
2325 	pmp = MPTOPMP(mp);
2326 	np = vfs_export_lookup(mp, &pmp->export, nam);
2327 	if (np) {
2328 		*exflagsp = np->netc_exflags;
2329 		*credanonp = &np->netc_anon;
2330 		error = 0;
2331 	} else {
2332 		error = EACCES;
2333 	}
2334 	return error;
2335 }
2336 
2337 /*
2338  * Support code for hammer2_vfs_mount().  Read, verify, and install the volume
2339  * header into the HMP
2340  *
2341  * XXX read four volhdrs and use the one with the highest TID whos CRC
2342  *     matches.
2343  *
2344  * XXX check iCRCs.
2345  *
2346  * XXX For filesystems w/ less than 4 volhdrs, make sure to not write to
2347  *     nonexistant locations.
2348  *
2349  * XXX Record selected volhdr and ring updates to each of 4 volhdrs
2350  */
2351 static
2352 int
2353 hammer2_install_volume_header(hammer2_dev_t *hmp)
2354 {
2355 	hammer2_volume_data_t *vd;
2356 	struct buf *bp;
2357 	hammer2_crc32_t crc0, crc, bcrc0, bcrc;
2358 	int error_reported;
2359 	int error;
2360 	int valid;
2361 	int i;
2362 
2363 	error_reported = 0;
2364 	error = 0;
2365 	valid = 0;
2366 	bp = NULL;
2367 
2368 	/*
2369 	 * There are up to 4 copies of the volume header (syncs iterate
2370 	 * between them so there is no single master).  We don't trust the
2371 	 * volu_size field so we don't know precisely how large the filesystem
2372 	 * is, so depend on the OS to return an error if we go beyond the
2373 	 * block device's EOF.
2374 	 */
2375 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
2376 		error = bread(hmp->devvp, i * HAMMER2_ZONE_BYTES64,
2377 			      HAMMER2_VOLUME_BYTES, &bp);
2378 		if (error) {
2379 			brelse(bp);
2380 			bp = NULL;
2381 			continue;
2382 		}
2383 
2384 		vd = (struct hammer2_volume_data *) bp->b_data;
2385 		if ((vd->magic != HAMMER2_VOLUME_ID_HBO) &&
2386 		    (vd->magic != HAMMER2_VOLUME_ID_ABO)) {
2387 			brelse(bp);
2388 			bp = NULL;
2389 			continue;
2390 		}
2391 
2392 		if (vd->magic == HAMMER2_VOLUME_ID_ABO) {
2393 			/* XXX: Reversed-endianness filesystem */
2394 			kprintf("hammer2: reverse-endian filesystem detected");
2395 			brelse(bp);
2396 			bp = NULL;
2397 			continue;
2398 		}
2399 
2400 		crc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT0];
2401 		crc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC0_OFF,
2402 				      HAMMER2_VOLUME_ICRC0_SIZE);
2403 		bcrc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT1];
2404 		bcrc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC1_OFF,
2405 				       HAMMER2_VOLUME_ICRC1_SIZE);
2406 		if ((crc0 != crc) || (bcrc0 != bcrc)) {
2407 			kprintf("hammer2 volume header crc "
2408 				"mismatch copy #%d %08x/%08x\n",
2409 				i, crc0, crc);
2410 			error_reported = 1;
2411 			brelse(bp);
2412 			bp = NULL;
2413 			continue;
2414 		}
2415 		if (valid == 0 || hmp->voldata.mirror_tid < vd->mirror_tid) {
2416 			valid = 1;
2417 			hmp->voldata = *vd;
2418 			hmp->volhdrno = i;
2419 		}
2420 		brelse(bp);
2421 		bp = NULL;
2422 	}
2423 	if (valid) {
2424 		hmp->volsync = hmp->voldata;
2425 		error = 0;
2426 		if (error_reported || bootverbose || 1) { /* 1/DEBUG */
2427 			kprintf("hammer2: using volume header #%d\n",
2428 				hmp->volhdrno);
2429 		}
2430 	} else {
2431 		error = EINVAL;
2432 		kprintf("hammer2: no valid volume headers found!\n");
2433 	}
2434 	return (error);
2435 }
2436 
2437 /*
2438  * This handles hysteresis on regular file flushes.  Because the BIOs are
2439  * routed to a thread it is possible for an excessive number to build up
2440  * and cause long front-end stalls long before the runningbuffspace limit
2441  * is hit, so we implement hammer2_flush_pipe to control the
2442  * hysteresis.
2443  *
2444  * This is a particular problem when compression is used.
2445  */
2446 void
2447 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
2448 {
2449 	atomic_add_int(&pmp->count_lwinprog, 1);
2450 }
2451 
2452 void
2453 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
2454 {
2455 	int lwinprog;
2456 
2457 	lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
2458 	if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
2459 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
2460 		atomic_clear_int(&pmp->count_lwinprog,
2461 				 HAMMER2_LWINPROG_WAITING);
2462 		wakeup(&pmp->count_lwinprog);
2463 	}
2464 	if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
2465 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
2466 		atomic_clear_int(&pmp->count_lwinprog,
2467 				 HAMMER2_LWINPROG_WAITING0);
2468 		wakeup(&pmp->count_lwinprog);
2469 	}
2470 }
2471 
2472 void
2473 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
2474 {
2475 	int lwinprog;
2476 	int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
2477 				    HAMMER2_LWINPROG_WAITING0;
2478 
2479 	for (;;) {
2480 		lwinprog = pmp->count_lwinprog;
2481 		cpu_ccfence();
2482 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2483 			break;
2484 		tsleep_interlock(&pmp->count_lwinprog, 0);
2485 		atomic_set_int(&pmp->count_lwinprog, lwflag);
2486 		lwinprog = pmp->count_lwinprog;
2487 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2488 			break;
2489 		tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
2490 	}
2491 }
2492 
2493 /*
2494  * Manage excessive memory resource use for chain and related
2495  * structures.
2496  */
2497 void
2498 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
2499 {
2500 	uint32_t waiting;
2501 	uint32_t count;
2502 	uint32_t limit;
2503 #if 0
2504 	static int zzticks;
2505 #endif
2506 
2507 	/*
2508 	 * Atomic check condition and wait.  Also do an early speedup of
2509 	 * the syncer to try to avoid hitting the wait.
2510 	 */
2511 	for (;;) {
2512 		waiting = pmp->inmem_dirty_chains;
2513 		cpu_ccfence();
2514 		count = waiting & HAMMER2_DIRTYCHAIN_MASK;
2515 
2516 		limit = pmp->mp->mnt_nvnodelistsize / 10;
2517 		if (limit < hammer2_limit_dirty_chains)
2518 			limit = hammer2_limit_dirty_chains;
2519 		if (limit < 1000)
2520 			limit = 1000;
2521 
2522 #if 0
2523 		if ((int)(ticks - zzticks) > hz) {
2524 			zzticks = ticks;
2525 			kprintf("count %ld %ld\n", count, limit);
2526 		}
2527 #endif
2528 
2529 		/*
2530 		 * Block if there are too many dirty chains present, wait
2531 		 * for the flush to clean some out.
2532 		 */
2533 		if (count > limit) {
2534 			tsleep_interlock(&pmp->inmem_dirty_chains, 0);
2535 			if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2536 					       waiting,
2537 				       waiting | HAMMER2_DIRTYCHAIN_WAITING)) {
2538 				speedup_syncer(pmp->mp);
2539 				tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED,
2540 				       "chnmem", hz);
2541 			}
2542 			continue;	/* loop on success or fail */
2543 		}
2544 
2545 		/*
2546 		 * Try to start an early flush before we are forced to block.
2547 		 */
2548 		if (count > limit * 7 / 10)
2549 			speedup_syncer(pmp->mp);
2550 		break;
2551 	}
2552 }
2553 
2554 void
2555 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
2556 {
2557 	if (pmp) {
2558 		atomic_add_int(&pmp->inmem_dirty_chains, 1);
2559 	}
2560 }
2561 
2562 void
2563 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp)
2564 {
2565 	uint32_t waiting;
2566 
2567 	if (pmp == NULL)
2568 		return;
2569 
2570 	for (;;) {
2571 		waiting = pmp->inmem_dirty_chains;
2572 		cpu_ccfence();
2573 		if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2574 				       waiting,
2575 				       (waiting - 1) &
2576 					~HAMMER2_DIRTYCHAIN_WAITING)) {
2577 			break;
2578 		}
2579 	}
2580 
2581 	if (waiting & HAMMER2_DIRTYCHAIN_WAITING)
2582 		wakeup(&pmp->inmem_dirty_chains);
2583 }
2584 
2585 /*
2586  * Debugging
2587  */
2588 void
2589 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int *countp, char pfx)
2590 {
2591 	hammer2_chain_t *scan;
2592 	hammer2_chain_t *parent;
2593 
2594 	--*countp;
2595 	if (*countp == 0) {
2596 		kprintf("%*.*s...\n", tab, tab, "");
2597 		return;
2598 	}
2599 	if (*countp < 0)
2600 		return;
2601 	kprintf("%*.*s%c-chain %p.%d %016jx/%d mir=%016jx\n",
2602 		tab, tab, "", pfx,
2603 		chain, chain->bref.type,
2604 		chain->bref.key, chain->bref.keybits,
2605 		chain->bref.mirror_tid);
2606 
2607 	kprintf("%*.*s      [%08x] (%s) refs=%d",
2608 		tab, tab, "",
2609 		chain->flags,
2610 		((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2611 		chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
2612 		chain->refs);
2613 
2614 	parent = chain->parent;
2615 	if (parent)
2616 		kprintf("\n%*.*s      p=%p [pflags %08x prefs %d",
2617 			tab, tab, "",
2618 			parent, parent->flags, parent->refs);
2619 	if (RB_EMPTY(&chain->core.rbtree)) {
2620 		kprintf("\n");
2621 	} else {
2622 		kprintf(" {\n");
2623 		RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree)
2624 			hammer2_dump_chain(scan, tab + 4, countp, 'a');
2625 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
2626 			kprintf("%*.*s}(%s)\n", tab, tab, "",
2627 				chain->data->ipdata.filename);
2628 		else
2629 			kprintf("%*.*s}\n", tab, tab, "");
2630 	}
2631 }
2632