xref: /dragonfly/sys/vfs/hammer2/hammer2_vfsops.c (revision 65cc0652)
1 /*
2  * Copyright (c) 2011-2017 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_supported_version = HAMMER2_VOL_VERSION_DEFAULT;
81 int hammer2_debug;
82 int hammer2_cluster_meta_read = 1;	/* physical read-ahead */
83 int hammer2_cluster_data_read = 4;	/* physical read-ahead */
84 int hammer2_dedup_enable = 1;
85 int hammer2_always_compress = 0;	/* always try to compress */
86 int hammer2_inval_enable = 0;
87 int hammer2_flush_pipe = 100;
88 int hammer2_synchronous_flush = 1;
89 int hammer2_dio_count;
90 int hammer2_limit_dio = 256;
91 int hammer2_bulkfree_tps = 5000;
92 long hammer2_chain_allocs;
93 long hammer2_chain_frees;
94 long hammer2_limit_dirty_chains;
95 long hammer2_count_modified_chains;
96 long hammer2_iod_invals;
97 long hammer2_iod_file_read;
98 long hammer2_iod_meta_read;
99 long hammer2_iod_indr_read;
100 long hammer2_iod_fmap_read;
101 long hammer2_iod_volu_read;
102 long hammer2_iod_file_write;
103 long hammer2_iod_file_wembed;
104 long hammer2_iod_file_wzero;
105 long hammer2_iod_file_wdedup;
106 long hammer2_iod_meta_write;
107 long hammer2_iod_indr_write;
108 long hammer2_iod_fmap_write;
109 long hammer2_iod_volu_write;
110 
111 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
112 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
113 		"Buffer used for compression.");
114 
115 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
116 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
117 		"Buffer used for decompression.");
118 
119 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
120 
121 SYSCTL_INT(_vfs_hammer2, OID_AUTO, supported_version, CTLFLAG_RD,
122 	   &hammer2_supported_version, 0, "");
123 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
124 	   &hammer2_debug, 0, "");
125 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_meta_read, CTLFLAG_RW,
126 	   &hammer2_cluster_meta_read, 0, "");
127 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_data_read, CTLFLAG_RW,
128 	   &hammer2_cluster_data_read, 0, "");
129 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dedup_enable, CTLFLAG_RW,
130 	   &hammer2_dedup_enable, 0, "");
131 SYSCTL_INT(_vfs_hammer2, OID_AUTO, always_compress, CTLFLAG_RW,
132 	   &hammer2_always_compress, 0, "");
133 SYSCTL_INT(_vfs_hammer2, OID_AUTO, inval_enable, CTLFLAG_RW,
134 	   &hammer2_inval_enable, 0, "");
135 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
136 	   &hammer2_flush_pipe, 0, "");
137 SYSCTL_INT(_vfs_hammer2, OID_AUTO, synchronous_flush, CTLFLAG_RW,
138 	   &hammer2_synchronous_flush, 0, "");
139 SYSCTL_INT(_vfs_hammer2, OID_AUTO, bulkfree_tps, CTLFLAG_RW,
140 	   &hammer2_bulkfree_tps, 0, "");
141 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_allocs, CTLFLAG_RW,
142 	   &hammer2_chain_allocs, 0, "");
143 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_frees, CTLFLAG_RW,
144 	   &hammer2_chain_frees, 0, "");
145 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
146 	   &hammer2_limit_dirty_chains, 0, "");
147 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, count_modified_chains, CTLFLAG_RW,
148 	   &hammer2_count_modified_chains, 0, "");
149 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
150 	   &hammer2_dio_count, 0, "");
151 SYSCTL_INT(_vfs_hammer2, OID_AUTO, limit_dio, CTLFLAG_RW,
152 	   &hammer2_limit_dio, 0, "");
153 
154 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_invals, CTLFLAG_RW,
155 	   &hammer2_iod_invals, 0, "");
156 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
157 	   &hammer2_iod_file_read, 0, "");
158 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
159 	   &hammer2_iod_meta_read, 0, "");
160 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
161 	   &hammer2_iod_indr_read, 0, "");
162 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
163 	   &hammer2_iod_fmap_read, 0, "");
164 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
165 	   &hammer2_iod_volu_read, 0, "");
166 
167 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
168 	   &hammer2_iod_file_write, 0, "");
169 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
170 	   &hammer2_iod_file_wembed, 0, "");
171 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
172 	   &hammer2_iod_file_wzero, 0, "");
173 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
174 	   &hammer2_iod_file_wdedup, 0, "");
175 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
176 	   &hammer2_iod_meta_write, 0, "");
177 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
178 	   &hammer2_iod_indr_write, 0, "");
179 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
180 	   &hammer2_iod_fmap_write, 0, "");
181 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
182 	   &hammer2_iod_volu_write, 0, "");
183 
184 long hammer2_check_icrc32;
185 long hammer2_check_xxhash64;
186 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_icrc32, CTLFLAG_RW,
187 	   &hammer2_check_icrc32, 0, "");
188 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_xxhash64, CTLFLAG_RW,
189 	   &hammer2_check_xxhash64, 0, "");
190 
191 static int hammer2_vfs_init(struct vfsconf *conf);
192 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
193 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
194 				struct ucred *cred);
195 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
196 				struct vnode *, struct ucred *);
197 static int hammer2_recovery(hammer2_dev_t *hmp);
198 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
199 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
200 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
201 				struct ucred *cred);
202 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
203 				struct ucred *cred);
204 static int hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
205 				struct fid *fhp, struct vnode **vpp);
206 static int hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp);
207 static int hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
208 				int *exflagsp, struct ucred **credanonp);
209 
210 static int hammer2_install_volume_header(hammer2_dev_t *hmp);
211 static int hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
212 
213 static void hammer2_update_pmps(hammer2_dev_t *hmp);
214 
215 static void hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp);
216 static void hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp,
217 				hammer2_dev_t *hmp);
218 
219 /*
220  * HAMMER2 vfs operations.
221  */
222 static struct vfsops hammer2_vfsops = {
223 	.vfs_init	= hammer2_vfs_init,
224 	.vfs_uninit	= hammer2_vfs_uninit,
225 	.vfs_sync	= hammer2_vfs_sync,
226 	.vfs_mount	= hammer2_vfs_mount,
227 	.vfs_unmount	= hammer2_vfs_unmount,
228 	.vfs_root 	= hammer2_vfs_root,
229 	.vfs_statfs	= hammer2_vfs_statfs,
230 	.vfs_statvfs	= hammer2_vfs_statvfs,
231 	.vfs_vget	= hammer2_vfs_vget,
232 	.vfs_vptofh	= hammer2_vfs_vptofh,
233 	.vfs_fhtovp	= hammer2_vfs_fhtovp,
234 	.vfs_checkexp	= hammer2_vfs_checkexp
235 };
236 
237 MALLOC_DEFINE(M_HAMMER2, "HAMMER2-mount", "");
238 
239 VFS_SET(hammer2_vfsops, hammer2, VFCF_MPSAFE);
240 MODULE_VERSION(hammer2, 1);
241 
242 static
243 int
244 hammer2_vfs_init(struct vfsconf *conf)
245 {
246 	static struct objcache_malloc_args margs_read;
247 	static struct objcache_malloc_args margs_write;
248 	static struct objcache_malloc_args margs_vop;
249 
250 	int error;
251 
252 	error = 0;
253 
254 	/*
255 	 * A large DIO cache is needed to retain dedup enablement masks.
256 	 * The bulkfree code clears related masks as part of the disk block
257 	 * recycling algorithm, preventing it from being used for a later
258 	 * dedup.
259 	 *
260 	 * NOTE: A large buffer cache can actually interfere with dedup
261 	 *	 operation because we dedup based on media physical buffers
262 	 *	 and not logical buffers.  Try to make the DIO chace large
263 	 *	 enough to avoid this problem, but also cap it.
264 	 */
265 	hammer2_limit_dio = nbuf * 2;
266 	if (hammer2_limit_dio > 100000)
267 		hammer2_limit_dio = 100000;
268 
269 	if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
270 		error = EINVAL;
271 	if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
272 		error = EINVAL;
273 	if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
274 		error = EINVAL;
275 
276 	if (error)
277 		kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
278 
279 	margs_read.objsize = 65536;
280 	margs_read.mtype = M_HAMMER2_DEBUFFER;
281 
282 	margs_write.objsize = 32768;
283 	margs_write.mtype = M_HAMMER2_CBUFFER;
284 
285 	margs_vop.objsize = sizeof(hammer2_xop_t);
286 	margs_vop.mtype = M_HAMMER2;
287 
288 	/*
289 	 * Note thaht for the XOPS cache we want backing store allocations
290 	 * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
291 	 * confusion), so use the backing store function that does it.  This
292 	 * means that initial XOPS objects are zerod but REUSED objects are
293 	 * not.  So we are responsible for cleaning the object up sufficiently
294 	 * for our needs before objcache_put()ing it back (typically just the
295 	 * FIFO indices).
296 	 */
297 	cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
298 				0, 1, NULL, NULL, NULL,
299 				objcache_malloc_alloc,
300 				objcache_malloc_free,
301 				&margs_read);
302 	cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
303 				0, 1, NULL, NULL, NULL,
304 				objcache_malloc_alloc,
305 				objcache_malloc_free,
306 				&margs_write);
307 	cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
308 				0, 1, NULL, NULL, NULL,
309 				objcache_malloc_alloc_zero,
310 				objcache_malloc_free,
311 				&margs_vop);
312 
313 
314 	lockinit(&hammer2_mntlk, "mntlk", 0, 0);
315 	TAILQ_INIT(&hammer2_mntlist);
316 	TAILQ_INIT(&hammer2_pfslist);
317 
318 	hammer2_limit_dirty_chains = maxvnodes / 10;
319 	if (hammer2_limit_dirty_chains > HAMMER2_LIMIT_DIRTY_CHAINS)
320 		hammer2_limit_dirty_chains = HAMMER2_LIMIT_DIRTY_CHAINS;
321 
322 	return (error);
323 }
324 
325 static
326 int
327 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
328 {
329 	objcache_destroy(cache_buffer_read);
330 	objcache_destroy(cache_buffer_write);
331 	objcache_destroy(cache_xops);
332 	return 0;
333 }
334 
335 /*
336  * Core PFS allocator.  Used to allocate or reference the pmp structure
337  * for PFS cluster mounts and the spmp structure for media (hmp) structures.
338  * The pmp can be passed in or loaded by this function using the chain and
339  * inode data.
340  *
341  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
342  * transactions.  Note that synchronization does not use this field.
343  * (typically frontend operations and synchronization cannot run on the
344  * same PFS node at the same time).
345  *
346  * XXX check locking
347  */
348 hammer2_pfs_t *
349 hammer2_pfsalloc(hammer2_chain_t *chain,
350 		 const hammer2_inode_data_t *ripdata,
351 		 hammer2_tid_t modify_tid, hammer2_dev_t *force_local)
352 {
353 	hammer2_pfs_t *pmp;
354 	hammer2_inode_t *iroot;
355 	int count;
356 	int i;
357 	int j;
358 
359 	pmp = NULL;
360 
361 	/*
362 	 * Locate or create the PFS based on the cluster id.  If ripdata
363 	 * is NULL this is a spmp which is unique and is always allocated.
364 	 *
365 	 * If the device is mounted in local mode all PFSs are considered
366 	 * independent and not part of any cluster (for debugging only).
367 	 */
368 	if (ripdata) {
369 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
370 			if (force_local != pmp->force_local)
371 				continue;
372 			if (force_local == NULL &&
373 			    bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
374 				 sizeof(pmp->pfs_clid)) == 0) {
375 					break;
376 			} else if (force_local && pmp->pfs_names[0] &&
377 			    strcmp(pmp->pfs_names[0], ripdata->filename) == 0) {
378 					break;
379 			}
380 		}
381 	}
382 
383 	if (pmp == NULL) {
384 		pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
385 		pmp->force_local = force_local;
386 		hammer2_trans_manage_init(pmp);
387 		kmalloc_create(&pmp->minode, "HAMMER2-inodes");
388 		kmalloc_create(&pmp->mmsg, "HAMMER2-pfsmsg");
389 		lockinit(&pmp->lock, "pfslk", 0, 0);
390 		lockinit(&pmp->lock_nlink, "h2nlink", 0, 0);
391 		spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
392 		spin_init(&pmp->xop_spin, "h2xop");
393 		spin_init(&pmp->lru_spin, "h2lru");
394 		RB_INIT(&pmp->inum_tree);
395 		TAILQ_INIT(&pmp->sideq);
396 		TAILQ_INIT(&pmp->lru_list);
397 		spin_init(&pmp->list_spin, "hm2pfsalloc_list");
398 
399 		/*
400 		 * Distribute backend operations to threads
401 		 */
402 		for (i = 0; i < HAMMER2_XOPGROUPS; ++i)
403 			hammer2_xop_group_init(pmp, &pmp->xop_groups[i]);
404 
405 		/*
406 		 * Save the last media transaction id for the flusher.  Set
407 		 * initial
408 		 */
409 		if (ripdata)
410 			pmp->pfs_clid = ripdata->meta.pfs_clid;
411 		TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
412 
413 		/*
414 		 * The synchronization thread may start too early, make
415 		 * sure it stays frozen until we are ready to let it go.
416 		 * XXX
417 		 */
418 		/*
419 		pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
420 					 HAMMER2_THREAD_REMASTER;
421 		*/
422 	}
423 
424 	/*
425 	 * Create the PFS's root inode and any missing XOP helper threads.
426 	 */
427 	if ((iroot = pmp->iroot) == NULL) {
428 		iroot = hammer2_inode_get(pmp, NULL, NULL, -1);
429 		if (ripdata)
430 			iroot->meta = ripdata->meta;
431 		pmp->iroot = iroot;
432 		hammer2_inode_ref(iroot);
433 		hammer2_inode_unlock(iroot);
434 	}
435 
436 	/*
437 	 * Stop here if no chain is passed in.
438 	 */
439 	if (chain == NULL)
440 		goto done;
441 
442 	/*
443 	 * When a chain is passed in we must add it to the PFS's root
444 	 * inode, update pmp->pfs_types[], and update the syncronization
445 	 * threads.
446 	 *
447 	 * When forcing local mode, mark the PFS as a MASTER regardless.
448 	 *
449 	 * At the moment empty spots can develop due to removals or failures.
450 	 * Ultimately we want to re-fill these spots but doing so might
451 	 * confused running code. XXX
452 	 */
453 	hammer2_inode_ref(iroot);
454 	hammer2_mtx_ex(&iroot->lock);
455 	j = iroot->cluster.nchains;
456 
457 	if (j == HAMMER2_MAXCLUSTER) {
458 		kprintf("hammer2_mount: cluster full!\n");
459 		/* XXX fatal error? */
460 	} else {
461 		KKASSERT(chain->pmp == NULL);
462 		chain->pmp = pmp;
463 		hammer2_chain_ref(chain);
464 		iroot->cluster.array[j].chain = chain;
465 		if (force_local)
466 			pmp->pfs_types[j] = HAMMER2_PFSTYPE_MASTER;
467 		else
468 			pmp->pfs_types[j] = ripdata->meta.pfs_type;
469 		pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
470 		pmp->pfs_hmps[j] = chain->hmp;
471 
472 		/*
473 		 * If the PFS is already mounted we must account
474 		 * for the mount_count here.
475 		 */
476 		if (pmp->mp)
477 			++chain->hmp->mount_count;
478 
479 		/*
480 		 * May have to fixup dirty chain tracking.  Previous
481 		 * pmp was NULL so nothing to undo.
482 		 */
483 		if (chain->flags & HAMMER2_CHAIN_MODIFIED)
484 			hammer2_pfs_memory_inc(pmp);
485 		++j;
486 	}
487 	iroot->cluster.nchains = j;
488 
489 	/*
490 	 * Update nmasters from any PFS inode which is part of the cluster.
491 	 * It is possible that this will result in a value which is too
492 	 * high.  MASTER PFSs are authoritative for pfs_nmasters and will
493 	 * override this value later on.
494 	 *
495 	 * (This informs us of masters that might not currently be
496 	 *  discoverable by this mount).
497 	 */
498 	if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
499 		pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
500 	}
501 
502 	/*
503 	 * Count visible masters.  Masters are usually added with
504 	 * ripdata->meta.pfs_nmasters set to 1.  This detects when there
505 	 * are more (XXX and must update the master inodes).
506 	 */
507 	count = 0;
508 	for (i = 0; i < iroot->cluster.nchains; ++i) {
509 		if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
510 			++count;
511 	}
512 	if (pmp->pfs_nmasters < count)
513 		pmp->pfs_nmasters = count;
514 
515 	/*
516 	 * Create missing synchronization and support threads.
517 	 *
518 	 * Single-node masters (including snapshots) have nothing to
519 	 * synchronize and do not require this thread.
520 	 *
521 	 * Multi-node masters or any number of soft masters, slaves, copy,
522 	 * or other PFS types need the thread.
523 	 *
524 	 * Each thread is responsible for its particular cluster index.
525 	 * We use independent threads so stalls or mismatches related to
526 	 * any given target do not affect other targets.
527 	 */
528 	for (i = 0; i < iroot->cluster.nchains; ++i) {
529 		/*
530 		 * Single-node masters (including snapshots) have nothing
531 		 * to synchronize and will make direct xops support calls,
532 		 * thus they do not require this thread.
533 		 *
534 		 * Note that there can be thousands of snapshots.  We do not
535 		 * want to create thousands of threads.
536 		 */
537 		if (pmp->pfs_nmasters <= 1 &&
538 		    pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
539 			continue;
540 		}
541 
542 		/*
543 		 * Sync support thread
544 		 */
545 		if (pmp->sync_thrs[i].td == NULL) {
546 			hammer2_thr_create(&pmp->sync_thrs[i], pmp, NULL,
547 					   "h2nod", i, -1,
548 					   hammer2_primary_sync_thread);
549 		}
550 	}
551 
552 	/*
553 	 * Create missing Xop threads
554 	 *
555 	 * NOTE: We create helper threads for all mounted PFSs or any
556 	 *	 PFSs with 2+ nodes (so the sync thread can update them,
557 	 *	 even if not mounted).
558 	 */
559 	if (pmp->mp || iroot->cluster.nchains >= 2)
560 		hammer2_xop_helper_create(pmp);
561 
562 	hammer2_mtx_unlock(&iroot->lock);
563 	hammer2_inode_drop(iroot);
564 done:
565 	return pmp;
566 }
567 
568 /*
569  * Deallocate an element of a probed PFS.  If destroying and this is a
570  * MASTER, adjust nmasters.
571  *
572  * This function does not physically destroy the PFS element in its device
573  * under the super-root  (see hammer2_ioctl_pfs_delete()).
574  */
575 void
576 hammer2_pfsdealloc(hammer2_pfs_t *pmp, int clindex, int destroying)
577 {
578 	hammer2_inode_t *iroot;
579 	hammer2_chain_t *chain;
580 	int j;
581 
582 	/*
583 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
584 	 * by the flush code.
585 	 */
586 	iroot = pmp->iroot;
587 	if (iroot) {
588 		/*
589 		 * Stop synchronizing
590 		 *
591 		 * XXX flush after acquiring the iroot lock.
592 		 * XXX clean out the cluster index from all inode structures.
593 		 */
594 		hammer2_thr_delete(&pmp->sync_thrs[clindex]);
595 
596 		/*
597 		 * Remove the cluster index from the group.  If destroying
598 		 * the PFS and this is a master, adjust pfs_nmasters.
599 		 */
600 		hammer2_mtx_ex(&iroot->lock);
601 		chain = iroot->cluster.array[clindex].chain;
602 		iroot->cluster.array[clindex].chain = NULL;
603 
604 		switch(pmp->pfs_types[clindex]) {
605 		case HAMMER2_PFSTYPE_MASTER:
606 			if (destroying && pmp->pfs_nmasters > 0)
607 				--pmp->pfs_nmasters;
608 			/* XXX adjust ripdata->meta.pfs_nmasters */
609 			break;
610 		default:
611 			break;
612 		}
613 		pmp->pfs_types[clindex] = HAMMER2_PFSTYPE_NONE;
614 
615 		hammer2_mtx_unlock(&iroot->lock);
616 
617 		/*
618 		 * Release the chain.
619 		 */
620 		if (chain) {
621 			atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
622 			hammer2_chain_drop(chain);
623 		}
624 
625 		/*
626 		 * Terminate all XOP threads for the cluster index.
627 		 */
628 		for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
629 			hammer2_thr_delete(&pmp->xop_groups[j].thrs[clindex]);
630 	}
631 }
632 
633 /*
634  * Destroy a PFS, typically only occurs after the last mount on a device
635  * has gone away.
636  */
637 static void
638 hammer2_pfsfree(hammer2_pfs_t *pmp)
639 {
640 	hammer2_inode_t *iroot;
641 	hammer2_chain_t *chain;
642 	int i;
643 	int j;
644 
645 	/*
646 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
647 	 * by the flush code.
648 	 */
649 	TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
650 
651 	iroot = pmp->iroot;
652 	if (iroot) {
653 		for (i = 0; i < iroot->cluster.nchains; ++i) {
654 			hammer2_thr_delete(&pmp->sync_thrs[i]);
655 			for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
656 				hammer2_thr_delete(&pmp->xop_groups[j].thrs[i]);
657 		}
658 #if REPORT_REFS_ERRORS
659 		if (pmp->iroot->refs != 1)
660 			kprintf("PMP->IROOT %p REFS WRONG %d\n",
661 				pmp->iroot, pmp->iroot->refs);
662 #else
663 		KKASSERT(pmp->iroot->refs == 1);
664 #endif
665 		/* ref for pmp->iroot */
666 		hammer2_inode_drop(pmp->iroot);
667 		pmp->iroot = NULL;
668 	}
669 
670 	/*
671 	 * Cleanup chains remaining on LRU list.
672 	 */
673 	while ((chain = TAILQ_FIRST(&pmp->lru_list)) != NULL) {
674 		hammer2_chain_ref(chain);
675 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
676 		hammer2_chain_drop(chain);
677 	}
678 
679 	/*
680 	 * Free remaining pmp resources
681 	 */
682 	kmalloc_destroy(&pmp->mmsg);
683 	kmalloc_destroy(&pmp->minode);
684 
685 	kfree(pmp, M_HAMMER2);
686 }
687 
688 /*
689  * Remove all references to hmp from the pfs list.  Any PFS which becomes
690  * empty is terminated and freed.
691  *
692  * XXX inefficient.
693  */
694 static void
695 hammer2_pfsfree_scan(hammer2_dev_t *hmp)
696 {
697 	hammer2_pfs_t *pmp;
698 	hammer2_inode_t *iroot;
699 	hammer2_chain_t *rchain;
700 	int didfreeze;
701 	int i;
702 	int j;
703 
704 again:
705 	TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
706 		if ((iroot = pmp->iroot) == NULL)
707 			continue;
708 		hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
709 		hammer2_inode_run_sideq(pmp, 1);
710 		hammer2_bioq_sync(pmp);
711 		hammer2_trans_done(pmp);
712 		if (hmp->spmp == pmp) {
713 			hmp->spmp = NULL;
714 			hmp->vchain.pmp = NULL;
715 			hmp->fchain.pmp = NULL;
716 		}
717 
718 		/*
719 		 * Determine if this PFS is affected.  If it is we must
720 		 * freeze all management threads and lock its iroot.
721 		 *
722 		 * Freezing a management thread forces it idle, operations
723 		 * in-progress will be aborted and it will have to start
724 		 * over again when unfrozen, or exit if told to exit.
725 		 */
726 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
727 			if (pmp->pfs_hmps[i] == hmp)
728 				break;
729 		}
730 		if (i != HAMMER2_MAXCLUSTER) {
731 			/*
732 			 * Make sure all synchronization threads are locked
733 			 * down.
734 			 */
735 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
736 				if (pmp->pfs_hmps[i] == NULL)
737 					continue;
738 				hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
739 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
740 					hammer2_thr_freeze_async(
741 						&pmp->xop_groups[j].thrs[i]);
742 				}
743 			}
744 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
745 				if (pmp->pfs_hmps[i] == NULL)
746 					continue;
747 				hammer2_thr_freeze(&pmp->sync_thrs[i]);
748 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
749 					hammer2_thr_freeze(
750 						&pmp->xop_groups[j].thrs[i]);
751 				}
752 			}
753 
754 			/*
755 			 * Lock the inode and clean out matching chains.
756 			 * Note that we cannot use hammer2_inode_lock_*()
757 			 * here because that would attempt to validate the
758 			 * cluster that we are in the middle of ripping
759 			 * apart.
760 			 *
761 			 * WARNING! We are working directly on the inodes
762 			 *	    embedded cluster.
763 			 */
764 			hammer2_mtx_ex(&iroot->lock);
765 
766 			/*
767 			 * Remove the chain from matching elements of the PFS.
768 			 */
769 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
770 				if (pmp->pfs_hmps[i] != hmp)
771 					continue;
772 				hammer2_thr_delete(&pmp->sync_thrs[i]);
773 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
774 					hammer2_thr_delete(
775 						&pmp->xop_groups[j].thrs[i]);
776 				}
777 				rchain = iroot->cluster.array[i].chain;
778 				iroot->cluster.array[i].chain = NULL;
779 				pmp->pfs_types[i] = 0;
780 				if (pmp->pfs_names[i]) {
781 					kfree(pmp->pfs_names[i], M_HAMMER2);
782 					pmp->pfs_names[i] = NULL;
783 				}
784 				if (rchain) {
785 					hammer2_chain_drop(rchain);
786 					/* focus hint */
787 					if (iroot->cluster.focus == rchain)
788 						iroot->cluster.focus = NULL;
789 				}
790 				pmp->pfs_hmps[i] = NULL;
791 			}
792 			hammer2_mtx_unlock(&iroot->lock);
793 			didfreeze = 1;	/* remaster, unfreeze down below */
794 		} else {
795 			didfreeze = 0;
796 		}
797 
798 		/*
799 		 * Cleanup trailing chains.  Gaps may remain.
800 		 */
801 		for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
802 			if (pmp->pfs_hmps[i])
803 				break;
804 		}
805 		iroot->cluster.nchains = i + 1;
806 
807 		/*
808 		 * If the PMP has no elements remaining we can destroy it.
809 		 * (this will transition management threads from frozen->exit).
810 		 */
811 		if (iroot->cluster.nchains == 0) {
812 			hammer2_pfsfree(pmp);
813 			goto again;
814 		}
815 
816 		/*
817 		 * If elements still remain we need to set the REMASTER
818 		 * flag and unfreeze it.
819 		 */
820 		if (didfreeze) {
821 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
822 				if (pmp->pfs_hmps[i] == NULL)
823 					continue;
824 				hammer2_thr_remaster(&pmp->sync_thrs[i]);
825 				hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
826 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
827 					hammer2_thr_remaster(
828 						&pmp->xop_groups[j].thrs[i]);
829 					hammer2_thr_unfreeze(
830 						&pmp->xop_groups[j].thrs[i]);
831 				}
832 			}
833 		}
834 	}
835 }
836 
837 /*
838  * Mount or remount HAMMER2 fileystem from physical media
839  *
840  *	mountroot
841  *		mp		mount point structure
842  *		path		NULL
843  *		data		<unused>
844  *		cred		<unused>
845  *
846  *	mount
847  *		mp		mount point structure
848  *		path		path to mount point
849  *		data		pointer to argument structure in user space
850  *			volume	volume path (device@LABEL form)
851  *			hflags	user mount flags
852  *		cred		user credentials
853  *
854  * RETURNS:	0	Success
855  *		!0	error number
856  */
857 static
858 int
859 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
860 		  struct ucred *cred)
861 {
862 	struct hammer2_mount_info info;
863 	hammer2_pfs_t *pmp;
864 	hammer2_pfs_t *spmp;
865 	hammer2_dev_t *hmp;
866 	hammer2_dev_t *force_local;
867 	hammer2_key_t key_next;
868 	hammer2_key_t key_dummy;
869 	hammer2_key_t lhc;
870 	struct vnode *devvp;
871 	struct nlookupdata nd;
872 	hammer2_chain_t *parent;
873 	hammer2_chain_t *chain;
874 	hammer2_cluster_t *cluster;
875 	const hammer2_inode_data_t *ripdata;
876 	hammer2_blockref_t bref;
877 	struct file *fp;
878 	char devstr[MNAMELEN];
879 	size_t size;
880 	size_t done;
881 	char *dev;
882 	char *label;
883 	int ronly = 1;
884 	int error;
885 	int i;
886 
887 	hmp = NULL;
888 	pmp = NULL;
889 	dev = NULL;
890 	label = NULL;
891 	devvp = NULL;
892 
893 	kprintf("hammer2_mount\n");
894 
895 	if (path == NULL) {
896 		/*
897 		 * Root mount
898 		 */
899 		bzero(&info, sizeof(info));
900 		info.cluster_fd = -1;
901 		ksnprintf(devstr, sizeof(devstr), "%s",
902 			  mp->mnt_stat.f_mntfromname);
903 		kprintf("hammer2_mount: root '%s'\n", devstr);
904 	} else {
905 		/*
906 		 * Non-root mount or updating a mount
907 		 */
908 		error = copyin(data, &info, sizeof(info));
909 		if (error)
910 			return (error);
911 
912 		error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
913 		if (error)
914 			return (error);
915 	}
916 
917 	/*
918 	 * Extract device and label, automatically mount @BOOT, @ROOT, or @DATA
919 	 * if no label specified, based on the partition id.  Error out if no
920 	 * label or device (with partition id) is specified.  This is strictly
921 	 * a convenience to match the default label created by newfs_hammer2,
922 	 * our preference is that a label always be specified.
923 	 *
924 	 * NOTE: We allow 'mount @LABEL <blah>'... that is, a mount command
925 	 *	 that does not specify a device, as long as some H2 label
926 	 *	 has already been mounted from that device.  This makes
927 	 *	 mounting snapshots a lot easier.
928 	 */
929 	dev = devstr;
930 	label = strchr(devstr, '@');
931 	if (label && ((label + 1) - dev) > done)
932 		return (EINVAL);
933 	if (label == NULL || label[1] == 0) {
934 		char slice;
935 
936 		if (label == NULL)
937 			label = devstr + strlen(devstr);
938 		slice = label[-1];
939 		switch(slice) {
940 		case 'a':
941 			label = "BOOT";
942 			break;
943 		case 'd':
944 			label = "ROOT";
945 			break;
946 		default:
947 			label = "DATA";
948 			break;
949 		}
950 	} else {
951 		*label = '\0';
952 		label++;
953 	}
954 
955 	kprintf("hammer2_mount: dev=\"%s\" label=\"%s\" rdonly=%d\n",
956 		dev, label, (mp->mnt_flag & MNT_RDONLY));
957 
958 	if (mp->mnt_flag & MNT_UPDATE) {
959 		/*
960 		 * Update mount.  Note that pmp->iroot->cluster is
961 		 * an inode-embedded cluster and thus cannot be
962 		 * directly locked.
963 		 *
964 		 * XXX HAMMER2 needs to implement NFS export via
965 		 *     mountctl.
966 		 */
967 		pmp = MPTOPMP(mp);
968 		pmp->hflags = info.hflags;
969 		cluster = &pmp->iroot->cluster;
970 		for (i = 0; i < cluster->nchains; ++i) {
971 			if (cluster->array[i].chain == NULL)
972 				continue;
973 			hmp = cluster->array[i].chain->hmp;
974 			devvp = hmp->devvp;
975 			error = hammer2_remount(hmp, mp, path,
976 						devvp, cred);
977 			if (error)
978 				break;
979 		}
980 
981 		return error;
982 	}
983 
984 	/*
985 	 * HMP device mount
986 	 *
987 	 * If a path is specified and dev is not an empty string, lookup the
988 	 * name and verify that it referes to a block device.
989 	 *
990 	 * If a path is specified and dev is an empty string we fall through
991 	 * and locate the label in the hmp search.
992 	 */
993 	if (path && *dev != 0) {
994 		error = nlookup_init(&nd, dev, UIO_SYSSPACE, NLC_FOLLOW);
995 		if (error == 0)
996 			error = nlookup(&nd);
997 		if (error == 0)
998 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
999 		nlookup_done(&nd);
1000 	} else if (path == NULL) {
1001 		/* root mount */
1002 		cdev_t cdev = kgetdiskbyname(dev);
1003 		error = bdevvp(cdev, &devvp);
1004 		if (error)
1005 			kprintf("hammer2: cannot find '%s'\n", dev);
1006 	} else {
1007 		/*
1008 		 * We will locate the hmp using the label in the hmp loop.
1009 		 */
1010 		error = 0;
1011 	}
1012 
1013 	/*
1014 	 * Make sure its a block device.  Do not check to see if it is
1015 	 * already mounted until we determine that its a fresh H2 device.
1016 	 */
1017 	if (error == 0 && devvp) {
1018 		vn_isdisk(devvp, &error);
1019 	}
1020 
1021 	/*
1022 	 * Determine if the device has already been mounted.  After this
1023 	 * check hmp will be non-NULL if we are doing the second or more
1024 	 * hammer2 mounts from the same device.
1025 	 */
1026 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1027 	if (devvp) {
1028 		/*
1029 		 * Match the device.  Due to the way devfs works,
1030 		 * we may not be able to directly match the vnode pointer,
1031 		 * so also check to see if the underlying device matches.
1032 		 */
1033 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1034 			if (hmp->devvp == devvp)
1035 				break;
1036 			if (devvp->v_rdev &&
1037 			    hmp->devvp->v_rdev == devvp->v_rdev) {
1038 				break;
1039 			}
1040 		}
1041 
1042 		/*
1043 		 * If no match this may be a fresh H2 mount, make sure
1044 		 * the device is not mounted on anything else.
1045 		 */
1046 		if (hmp == NULL)
1047 			error = vfs_mountedon(devvp);
1048 	} else if (error == 0) {
1049 		/*
1050 		 * Match the label to a pmp already probed.
1051 		 */
1052 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
1053 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
1054 				if (pmp->pfs_names[i] &&
1055 				    strcmp(pmp->pfs_names[i], label) == 0) {
1056 					hmp = pmp->pfs_hmps[i];
1057 					break;
1058 				}
1059 			}
1060 			if (hmp)
1061 				break;
1062 		}
1063 		if (hmp == NULL)
1064 			error = ENOENT;
1065 	}
1066 
1067 	/*
1068 	 * Open the device if this isn't a secondary mount and construct
1069 	 * the H2 device mount (hmp).
1070 	 */
1071 	if (hmp == NULL) {
1072 		hammer2_chain_t *schain;
1073 		hammer2_xid_t xid;
1074 
1075 		if (error == 0 && vcount(devvp) > 0) {
1076 			kprintf("Primary device already has references\n");
1077 			error = EBUSY;
1078 		}
1079 
1080 		/*
1081 		 * Now open the device
1082 		 */
1083 		if (error == 0) {
1084 			ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
1085 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1086 			error = vinvalbuf(devvp, V_SAVE, 0, 0);
1087 			if (error == 0) {
1088 				error = VOP_OPEN(devvp,
1089 					     (ronly ? FREAD : FREAD | FWRITE),
1090 					     FSCRED, NULL);
1091 			}
1092 			vn_unlock(devvp);
1093 		}
1094 		if (error && devvp) {
1095 			vrele(devvp);
1096 			devvp = NULL;
1097 		}
1098 		if (error) {
1099 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1100 			return error;
1101 		}
1102 		hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
1103 		ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
1104 		hmp->ronly = ronly;
1105 		hmp->devvp = devvp;
1106 		hmp->hflags = info.hflags & HMNT2_DEVFLAGS;
1107 		kmalloc_create(&hmp->mchain, "HAMMER2-chains");
1108 		TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
1109 		RB_INIT(&hmp->iotree);
1110 		spin_init(&hmp->io_spin, "hm2mount_io");
1111 		spin_init(&hmp->list_spin, "hm2mount_list");
1112 		TAILQ_INIT(&hmp->flushq);
1113 
1114 		lockinit(&hmp->vollk, "h2vol", 0, 0);
1115 		lockinit(&hmp->bulklk, "h2bulk", 0, 0);
1116 		lockinit(&hmp->bflock, "h2bflk", 0, 0);
1117 
1118 		/*
1119 		 * vchain setup. vchain.data is embedded.
1120 		 * vchain.refs is initialized and will never drop to 0.
1121 		 *
1122 		 * NOTE! voldata is not yet loaded.
1123 		 */
1124 		hmp->vchain.hmp = hmp;
1125 		hmp->vchain.refs = 1;
1126 		hmp->vchain.data = (void *)&hmp->voldata;
1127 		hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
1128 		hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1129 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1130 
1131 		hammer2_chain_core_init(&hmp->vchain);
1132 		/* hmp->vchain.u.xxx is left NULL */
1133 
1134 		/*
1135 		 * fchain setup.  fchain.data is embedded.
1136 		 * fchain.refs is initialized and will never drop to 0.
1137 		 *
1138 		 * The data is not used but needs to be initialized to
1139 		 * pass assertion muster.  We use this chain primarily
1140 		 * as a placeholder for the freemap's top-level RBTREE
1141 		 * so it does not interfere with the volume's topology
1142 		 * RBTREE.
1143 		 */
1144 		hmp->fchain.hmp = hmp;
1145 		hmp->fchain.refs = 1;
1146 		hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
1147 		hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
1148 		hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1149 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1150 		hmp->fchain.bref.methods =
1151 			HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
1152 			HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
1153 
1154 		hammer2_chain_core_init(&hmp->fchain);
1155 		/* hmp->fchain.u.xxx is left NULL */
1156 
1157 		/*
1158 		 * Install the volume header and initialize fields from
1159 		 * voldata.
1160 		 */
1161 		error = hammer2_install_volume_header(hmp);
1162 		if (error) {
1163 			hammer2_unmount_helper(mp, NULL, hmp);
1164 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1165 			hammer2_vfs_unmount(mp, MNT_FORCE);
1166 			return error;
1167 		}
1168 
1169 		/*
1170 		 * Really important to get these right or flush will get
1171 		 * confused.
1172 		 */
1173 		hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0, NULL);
1174 		kprintf("alloc spmp %p tid %016jx\n",
1175 			hmp->spmp, hmp->voldata.mirror_tid);
1176 		spmp = hmp->spmp;
1177 
1178 		/*
1179 		 * Dummy-up vchain and fchain's modify_tid.  mirror_tid
1180 		 * is inherited from the volume header.
1181 		 */
1182 		xid = 0;
1183 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1184 		hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
1185 		hmp->vchain.pmp = spmp;
1186 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1187 		hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
1188 		hmp->fchain.pmp = spmp;
1189 
1190 		/*
1191 		 * First locate the super-root inode, which is key 0
1192 		 * relative to the volume header's blockset.
1193 		 *
1194 		 * Then locate the root inode by scanning the directory keyspace
1195 		 * represented by the label.
1196 		 */
1197 		parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1198 		schain = hammer2_chain_lookup(&parent, &key_dummy,
1199 				      HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
1200 				      &error, 0);
1201 		hammer2_chain_lookup_done(parent);
1202 		if (schain == NULL) {
1203 			kprintf("hammer2_mount: invalid super-root\n");
1204 			hammer2_unmount_helper(mp, NULL, hmp);
1205 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1206 			hammer2_vfs_unmount(mp, MNT_FORCE);
1207 			return EINVAL;
1208 		}
1209 		if (schain->error) {
1210 			kprintf("hammer2_mount: error %s reading super-root\n",
1211 				hammer2_error_str(schain->error));
1212 			hammer2_chain_unlock(schain);
1213 			hammer2_chain_drop(schain);
1214 			schain = NULL;
1215 			hammer2_unmount_helper(mp, NULL, hmp);
1216 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1217 			hammer2_vfs_unmount(mp, MNT_FORCE);
1218 			return EINVAL;
1219 		}
1220 
1221 		/*
1222 		 * The super-root always uses an inode_tid of 1 when
1223 		 * creating PFSs.
1224 		 */
1225 		spmp->inode_tid = 1;
1226 		spmp->modify_tid = schain->bref.modify_tid + 1;
1227 
1228 		/*
1229 		 * Sanity-check schain's pmp and finish initialization.
1230 		 * Any chain belonging to the super-root topology should
1231 		 * have a NULL pmp (not even set to spmp).
1232 		 */
1233 		ripdata = &hammer2_chain_rdata(schain)->ipdata;
1234 		KKASSERT(schain->pmp == NULL);
1235 		spmp->pfs_clid = ripdata->meta.pfs_clid;
1236 
1237 		/*
1238 		 * Replace the dummy spmp->iroot with a real one.  It's
1239 		 * easier to just do a wholesale replacement than to try
1240 		 * to update the chain and fixup the iroot fields.
1241 		 *
1242 		 * The returned inode is locked with the supplied cluster.
1243 		 */
1244 		cluster = hammer2_cluster_from_chain(schain);
1245 		hammer2_inode_drop(spmp->iroot);
1246 		spmp->iroot = NULL;
1247 		spmp->iroot = hammer2_inode_get(spmp, NULL, cluster, -1);
1248 		spmp->spmp_hmp = hmp;
1249 		spmp->pfs_types[0] = ripdata->meta.pfs_type;
1250 		spmp->pfs_hmps[0] = hmp;
1251 		hammer2_inode_ref(spmp->iroot);
1252 		hammer2_inode_unlock(spmp->iroot);
1253 		hammer2_cluster_unlock(cluster);
1254 		hammer2_cluster_drop(cluster);
1255 		schain = NULL;
1256 		/* leave spmp->iroot with one ref */
1257 
1258 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1259 			error = hammer2_recovery(hmp);
1260 			/* XXX do something with error */
1261 		}
1262 		hammer2_update_pmps(hmp);
1263 		hammer2_iocom_init(hmp);
1264 		hammer2_bulkfree_init(hmp);
1265 
1266 		/*
1267 		 * Ref the cluster management messaging descriptor.  The mount
1268 		 * program deals with the other end of the communications pipe.
1269 		 *
1270 		 * Root mounts typically do not supply one.
1271 		 */
1272 		if (info.cluster_fd >= 0) {
1273 			fp = holdfp(curproc->p_fd, info.cluster_fd, -1);
1274 			if (fp) {
1275 				hammer2_cluster_reconnect(hmp, fp);
1276 			} else {
1277 				kprintf("hammer2_mount: bad cluster_fd!\n");
1278 			}
1279 		}
1280 	} else {
1281 		spmp = hmp->spmp;
1282 		if (info.hflags & HMNT2_DEVFLAGS) {
1283 			kprintf("hammer2: Warning: mount flags pertaining "
1284 				"to the whole device may only be specified "
1285 				"on the first mount of the device: %08x\n",
1286 				info.hflags & HMNT2_DEVFLAGS);
1287 		}
1288 	}
1289 
1290 	/*
1291 	 * Force local mount (disassociate all PFSs from their clusters).
1292 	 * Used primarily for debugging.
1293 	 */
1294 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1295 
1296 	/*
1297 	 * Lookup the mount point under the media-localized super-root.
1298 	 * Scanning hammer2_pfslist doesn't help us because it represents
1299 	 * PFS cluster ids which can aggregate several named PFSs together.
1300 	 *
1301 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1302 	 * up later on.
1303 	 */
1304 	hammer2_inode_lock(spmp->iroot, 0);
1305 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1306 	lhc = hammer2_dirhash(label, strlen(label));
1307 	chain = hammer2_chain_lookup(&parent, &key_next,
1308 				     lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1309 				     &error, 0);
1310 	while (chain) {
1311 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1312 		    strcmp(label, chain->data->ipdata.filename) == 0) {
1313 			break;
1314 		}
1315 		chain = hammer2_chain_next(&parent, chain, &key_next,
1316 					    key_next,
1317 					    lhc + HAMMER2_DIRHASH_LOMASK,
1318 					    &error, 0);
1319 	}
1320 	if (parent) {
1321 		hammer2_chain_unlock(parent);
1322 		hammer2_chain_drop(parent);
1323 	}
1324 	hammer2_inode_unlock(spmp->iroot);
1325 
1326 	/*
1327 	 * PFS could not be found?
1328 	 */
1329 	if (chain == NULL) {
1330 		if (error)
1331 			kprintf("hammer2_mount: PFS label I/O error\n");
1332 		else
1333 			kprintf("hammer2_mount: PFS label not found\n");
1334 		hammer2_unmount_helper(mp, NULL, hmp);
1335 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1336 		hammer2_vfs_unmount(mp, MNT_FORCE);
1337 
1338 		return EINVAL;
1339 	}
1340 
1341 	/*
1342 	 * Acquire the pmp structure (it should have already been allocated
1343 	 * via hammer2_update_pmps() so do not pass cluster in to add to
1344 	 * available chains).
1345 	 *
1346 	 * Check if the cluster has already been mounted.  A cluster can
1347 	 * only be mounted once, use null mounts to mount additional copies.
1348 	 */
1349 	if (chain->error) {
1350 		kprintf("hammer2_mount: PFS label I/O error\n");
1351 	} else {
1352 		ripdata = &chain->data->ipdata;
1353 		bref = chain->bref;
1354 		pmp = hammer2_pfsalloc(NULL, ripdata,
1355 				       bref.modify_tid, force_local);
1356 	}
1357 	hammer2_chain_unlock(chain);
1358 	hammer2_chain_drop(chain);
1359 
1360 	/*
1361 	 * Finish the mount
1362 	 */
1363         kprintf("hammer2_mount hmp=%p pmp=%p\n", hmp, pmp);
1364 
1365 	if (pmp->mp) {
1366 		kprintf("hammer2_mount: PFS already mounted!\n");
1367 		hammer2_unmount_helper(mp, NULL, hmp);
1368 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1369 		hammer2_vfs_unmount(mp, MNT_FORCE);
1370 
1371 		return EBUSY;
1372 	}
1373 
1374 	pmp->hflags = info.hflags;
1375         mp->mnt_flag |= MNT_LOCAL;
1376         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1377         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1378 
1379         /*
1380          * required mount structure initializations
1381          */
1382         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1383         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1384 
1385         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1386         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1387 
1388         /*
1389          * Optional fields
1390          */
1391         mp->mnt_iosize_max = MAXPHYS;
1392 
1393 	/*
1394 	 * Connect up mount pointers.
1395 	 */
1396 	hammer2_mount_helper(mp, pmp);
1397 
1398         lockmgr(&hammer2_mntlk, LK_RELEASE);
1399 
1400 	/*
1401 	 * Finish setup
1402 	 */
1403 	vfs_getnewfsid(mp);
1404 	vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1405 	vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1406 	vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1407 
1408 	if (path) {
1409 		copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1410 			  MNAMELEN - 1, &size);
1411 		bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1412 	} /* else root mount, already in there */
1413 
1414 	bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1415 	if (path) {
1416 		copyinstr(path, mp->mnt_stat.f_mntonname,
1417 			  sizeof(mp->mnt_stat.f_mntonname) - 1,
1418 			  &size);
1419 	} else {
1420 		/* root mount */
1421 		mp->mnt_stat.f_mntonname[0] = '/';
1422 	}
1423 
1424 	/*
1425 	 * Initial statfs to prime mnt_stat.
1426 	 */
1427 	hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1428 
1429 	return 0;
1430 }
1431 
1432 /*
1433  * Scan PFSs under the super-root and create hammer2_pfs structures.
1434  */
1435 static
1436 void
1437 hammer2_update_pmps(hammer2_dev_t *hmp)
1438 {
1439 	const hammer2_inode_data_t *ripdata;
1440 	hammer2_chain_t *parent;
1441 	hammer2_chain_t *chain;
1442 	hammer2_blockref_t bref;
1443 	hammer2_dev_t *force_local;
1444 	hammer2_pfs_t *spmp;
1445 	hammer2_pfs_t *pmp;
1446 	hammer2_key_t key_next;
1447 	int error;
1448 
1449 	/*
1450 	 * Force local mount (disassociate all PFSs from their clusters).
1451 	 * Used primarily for debugging.
1452 	 */
1453 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1454 
1455 	/*
1456 	 * Lookup mount point under the media-localized super-root.
1457 	 *
1458 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1459 	 * up later on.
1460 	 */
1461 	spmp = hmp->spmp;
1462 	hammer2_inode_lock(spmp->iroot, 0);
1463 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1464 	chain = hammer2_chain_lookup(&parent, &key_next,
1465 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1466 					 &error, 0);
1467 	while (chain) {
1468 		if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
1469 			continue;
1470 		if (chain->error) {
1471 			kprintf("I/O error scanning PFS labels\n");
1472 		} else {
1473 			ripdata = &chain->data->ipdata;
1474 			bref = chain->bref;
1475 
1476 			pmp = hammer2_pfsalloc(chain, ripdata,
1477 					       bref.modify_tid, force_local);
1478 		}
1479 		chain = hammer2_chain_next(&parent, chain, &key_next,
1480 					   key_next, HAMMER2_KEY_MAX,
1481 					   &error, 0);
1482 	}
1483 	if (parent) {
1484 		hammer2_chain_unlock(parent);
1485 		hammer2_chain_drop(parent);
1486 	}
1487 	hammer2_inode_unlock(spmp->iroot);
1488 }
1489 
1490 static
1491 int
1492 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1493 		struct vnode *devvp, struct ucred *cred)
1494 {
1495 	int error;
1496 
1497 	if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
1498 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1499 		VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, NULL);
1500 		vn_unlock(devvp);
1501 		error = hammer2_recovery(hmp);
1502 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1503 		if (error == 0) {
1504 			VOP_CLOSE(devvp, FREAD, NULL);
1505 			hmp->ronly = 0;
1506 		} else {
1507 			VOP_CLOSE(devvp, FREAD | FWRITE, NULL);
1508 		}
1509 		vn_unlock(devvp);
1510 	} else {
1511 		error = 0;
1512 	}
1513 	return error;
1514 }
1515 
1516 static
1517 int
1518 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1519 {
1520 	hammer2_pfs_t *pmp;
1521 	int flags;
1522 	int error = 0;
1523 
1524 	pmp = MPTOPMP(mp);
1525 
1526 	if (pmp == NULL)
1527 		return(0);
1528 
1529 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1530 
1531 	/*
1532 	 * If mount initialization proceeded far enough we must flush
1533 	 * its vnodes and sync the underlying mount points.  Three syncs
1534 	 * are required to fully flush the filesystem (freemap updates lag
1535 	 * by one flush, and one extra for safety).
1536 	 */
1537 	if (mntflags & MNT_FORCE)
1538 		flags = FORCECLOSE;
1539 	else
1540 		flags = 0;
1541 	if (pmp->iroot) {
1542 		error = vflush(mp, 0, flags);
1543 		if (error)
1544 			goto failed;
1545 		hammer2_vfs_sync(mp, MNT_WAIT);
1546 		hammer2_vfs_sync(mp, MNT_WAIT);
1547 		hammer2_vfs_sync(mp, MNT_WAIT);
1548 	}
1549 
1550 	/*
1551 	 * Cleanup the frontend support XOPS threads
1552 	 */
1553 	hammer2_xop_helper_cleanup(pmp);
1554 
1555 	if (pmp->mp)
1556 		hammer2_unmount_helper(mp, pmp, NULL);
1557 
1558 	error = 0;
1559 failed:
1560 	lockmgr(&hammer2_mntlk, LK_RELEASE);
1561 
1562 	return (error);
1563 }
1564 
1565 /*
1566  * Mount helper, hook the system mount into our PFS.
1567  * The mount lock is held.
1568  *
1569  * We must bump the mount_count on related devices for any
1570  * mounted PFSs.
1571  */
1572 static
1573 void
1574 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1575 {
1576 	hammer2_cluster_t *cluster;
1577 	hammer2_chain_t *rchain;
1578 	int i;
1579 
1580         mp->mnt_data = (qaddr_t)pmp;
1581 	pmp->mp = mp;
1582 
1583 	/*
1584 	 * After pmp->mp is set we have to adjust hmp->mount_count.
1585 	 */
1586 	cluster = &pmp->iroot->cluster;
1587 	for (i = 0; i < cluster->nchains; ++i) {
1588 		rchain = cluster->array[i].chain;
1589 		if (rchain == NULL)
1590 			continue;
1591 		++rchain->hmp->mount_count;
1592 		kprintf("hammer2_mount hmp=%p ++mount_count=%d\n",
1593 			rchain->hmp, rchain->hmp->mount_count);
1594 	}
1595 
1596 	/*
1597 	 * Create missing Xop threads
1598 	 */
1599 	hammer2_xop_helper_create(pmp);
1600 }
1601 
1602 /*
1603  * Mount helper, unhook the system mount from our PFS.
1604  * The mount lock is held.
1605  *
1606  * If hmp is supplied a mount responsible for being the first to open
1607  * the block device failed and the block device and all PFSs using the
1608  * block device must be cleaned up.
1609  *
1610  * If pmp is supplied multiple devices might be backing the PFS and each
1611  * must be disconnected.  This might not be the last PFS using some of the
1612  * underlying devices.  Also, we have to adjust our hmp->mount_count
1613  * accounting for the devices backing the pmp which is now undergoing an
1614  * unmount.
1615  */
1616 static
1617 void
1618 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1619 {
1620 	hammer2_cluster_t *cluster;
1621 	hammer2_chain_t *rchain;
1622 	struct vnode *devvp;
1623 	int dumpcnt;
1624 	int ronly;
1625 	int i;
1626 
1627 	/*
1628 	 * If no device supplied this is a high-level unmount and we have to
1629 	 * to disconnect the mount, adjust mount_count, and locate devices
1630 	 * that might now have no mounts.
1631 	 */
1632 	if (pmp) {
1633 		KKASSERT(hmp == NULL);
1634 		KKASSERT((void *)(intptr_t)mp->mnt_data == pmp);
1635 		pmp->mp = NULL;
1636 		mp->mnt_data = NULL;
1637 
1638 		/*
1639 		 * After pmp->mp is cleared we have to account for
1640 		 * mount_count.
1641 		 */
1642 		cluster = &pmp->iroot->cluster;
1643 		for (i = 0; i < cluster->nchains; ++i) {
1644 			rchain = cluster->array[i].chain;
1645 			if (rchain == NULL)
1646 				continue;
1647 			--rchain->hmp->mount_count;
1648 			/* scrapping hmp now may invalidate the pmp */
1649 		}
1650 again:
1651 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1652 			if (hmp->mount_count == 0) {
1653 				hammer2_unmount_helper(NULL, NULL, hmp);
1654 				goto again;
1655 			}
1656 		}
1657 		return;
1658 	}
1659 
1660 	/*
1661 	 * Try to terminate the block device.  We can't terminate it if
1662 	 * there are still PFSs referencing it.
1663 	 */
1664 	if (hmp->mount_count)
1665 		return;
1666 
1667 	/*
1668 	 * Decomission the network before we start messing with the
1669 	 * device and PFS.
1670 	 */
1671 	hammer2_iocom_uninit(hmp);
1672 
1673 	hammer2_bulkfree_uninit(hmp);
1674 	hammer2_pfsfree_scan(hmp);
1675 	hammer2_dev_exlock(hmp);	/* XXX order */
1676 
1677 	/*
1678 	 * Cycle the volume data lock as a safety (probably not needed any
1679 	 * more).  To ensure everything is out we need to flush at least
1680 	 * three times.  (1) The running of the sideq can dirty the
1681 	 * filesystem, (2) A normal flush can dirty the freemap, and
1682 	 * (3) ensure that the freemap is fully synchronized.
1683 	 *
1684 	 * The next mount's recovery scan can clean everything up but we want
1685 	 * to leave the filesystem in a 100% clean state on a normal unmount.
1686 	 */
1687 #if 0
1688 	hammer2_voldata_lock(hmp);
1689 	hammer2_voldata_unlock(hmp);
1690 #endif
1691 
1692 	/*
1693 	 * Flush whatever is left.  Unmounted but modified PFS's might still
1694 	 * have some dirty chains on them.
1695 	 */
1696 	hammer2_chain_lock(&hmp->vchain, HAMMER2_RESOLVE_ALWAYS);
1697 	hammer2_chain_lock(&hmp->fchain, HAMMER2_RESOLVE_ALWAYS);
1698 	hammer2_flush(&hmp->fchain, HAMMER2_FLUSH_TOP | HAMMER2_FLUSH_ALL);
1699 	hammer2_chain_unlock(&hmp->fchain);
1700 	hammer2_flush(&hmp->vchain, HAMMER2_FLUSH_TOP | HAMMER2_FLUSH_ALL);
1701 	hammer2_chain_unlock(&hmp->vchain);
1702 
1703 	if ((hmp->vchain.flags | hmp->fchain.flags) &
1704 	    HAMMER2_CHAIN_FLUSH_MASK) {
1705 		kprintf("hammer2_unmount: chains left over "
1706 			"after final sync\n");
1707 		kprintf("    vchain %08x\n", hmp->vchain.flags);
1708 		kprintf("    fchain %08x\n", hmp->fchain.flags);
1709 
1710 		if (hammer2_debug & 0x0010)
1711 			Debugger("entered debugger");
1712 	}
1713 
1714 	KKASSERT(hmp->spmp == NULL);
1715 
1716 	/*
1717 	 * Finish up with the device vnode
1718 	 */
1719 	if ((devvp = hmp->devvp) != NULL) {
1720 		ronly = hmp->ronly;
1721 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1722 		kprintf("hammer2_unmount(A): devvp %s rbdirty %p ronly=%d\n",
1723 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree),
1724 			ronly);
1725 		vinvalbuf(devvp, (ronly ? 0 : V_SAVE), 0, 0);
1726 		kprintf("hammer2_unmount(B): devvp %s rbdirty %p\n",
1727 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree));
1728 		hmp->devvp = NULL;
1729 		VOP_CLOSE(devvp, (ronly ? FREAD : FREAD|FWRITE), NULL);
1730 		vn_unlock(devvp);
1731 		vrele(devvp);
1732 		devvp = NULL;
1733 	}
1734 
1735 	/*
1736 	 * Clear vchain/fchain flags that might prevent final cleanup
1737 	 * of these chains.
1738 	 */
1739 	if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1740 		atomic_add_long(&hammer2_count_modified_chains, -1);
1741 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1742 		hammer2_pfs_memory_wakeup(hmp->vchain.pmp);
1743 	}
1744 	if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1745 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_UPDATE);
1746 	}
1747 
1748 	if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1749 		atomic_add_long(&hammer2_count_modified_chains, -1);
1750 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_MODIFIED);
1751 		hammer2_pfs_memory_wakeup(hmp->fchain.pmp);
1752 	}
1753 	if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1754 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_UPDATE);
1755 	}
1756 
1757 	/*
1758 	 * Final drop of embedded freemap root chain to
1759 	 * clean up fchain.core (fchain structure is not
1760 	 * flagged ALLOCATED so it is cleaned out and then
1761 	 * left to rot).
1762 	 */
1763 	hammer2_chain_drop(&hmp->fchain);
1764 
1765 	/*
1766 	 * Final drop of embedded volume root chain to clean
1767 	 * up vchain.core (vchain structure is not flagged
1768 	 * ALLOCATED so it is cleaned out and then left to
1769 	 * rot).
1770 	 */
1771 	dumpcnt = 50;
1772 	hammer2_dump_chain(&hmp->vchain, 0, &dumpcnt, 'v');
1773 	dumpcnt = 50;
1774 	hammer2_dump_chain(&hmp->fchain, 0, &dumpcnt, 'f');
1775 	hammer2_dev_unlock(hmp);
1776 	hammer2_chain_drop(&hmp->vchain);
1777 
1778 	hammer2_io_cleanup(hmp, &hmp->iotree);
1779 	if (hmp->iofree_count) {
1780 		kprintf("io_cleanup: %d I/O's left hanging\n",
1781 			hmp->iofree_count);
1782 	}
1783 
1784 	TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1785 	kmalloc_destroy(&hmp->mchain);
1786 	kfree(hmp, M_HAMMER2);
1787 }
1788 
1789 int
1790 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1791 		 ino_t ino, struct vnode **vpp)
1792 {
1793 	hammer2_xop_lookup_t *xop;
1794 	hammer2_pfs_t *pmp;
1795 	hammer2_inode_t *ip;
1796 	hammer2_tid_t inum;
1797 	int error;
1798 
1799 	inum = (hammer2_tid_t)ino & HAMMER2_DIRHASH_USERMSK;
1800 
1801 	error = 0;
1802 	pmp = MPTOPMP(mp);
1803 
1804 	/*
1805 	 * Easy if we already have it cached
1806 	 */
1807 	ip = hammer2_inode_lookup(pmp, inum);
1808 	if (ip) {
1809 		hammer2_inode_lock(ip, HAMMER2_RESOLVE_SHARED);
1810 		*vpp = hammer2_igetv(ip, &error);
1811 		hammer2_inode_unlock(ip);
1812 		hammer2_inode_drop(ip);		/* from lookup */
1813 
1814 		return error;
1815 	}
1816 
1817 	/*
1818 	 * Otherwise we have to find the inode
1819 	 */
1820 	xop = hammer2_xop_alloc(pmp->iroot, 0);
1821 	xop->lhc = inum;
1822 	hammer2_xop_start(&xop->head, hammer2_xop_lookup);
1823 	error = hammer2_xop_collect(&xop->head, 0);
1824 
1825 	if (error == 0) {
1826 		if (hammer2_cluster_rdata(&xop->head.cluster) == NULL) {
1827 			kprintf("vget: no collect error but also no rdata\n");
1828 			kprintf("xop %p\n", xop);
1829 			while ((hammer2_debug & 0x80000) == 0) {
1830 				tsleep(xop, PCATCH, "wait", hz * 10);
1831 			}
1832 			ip = NULL;
1833 		} else {
1834 			ip = hammer2_inode_get(pmp, NULL, &xop->head.cluster, -1);
1835 		}
1836 	}
1837 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1838 
1839 	if (ip) {
1840 		*vpp = hammer2_igetv(ip, &error);
1841 		hammer2_inode_unlock(ip);
1842 	} else {
1843 		*vpp = NULL;
1844 		error = ENOENT;
1845 	}
1846 	return (error);
1847 }
1848 
1849 static
1850 int
1851 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1852 {
1853 	hammer2_pfs_t *pmp;
1854 	struct vnode *vp;
1855 	int error;
1856 
1857 	pmp = MPTOPMP(mp);
1858 	if (pmp->iroot == NULL) {
1859 		*vpp = NULL;
1860 		return EINVAL;
1861 	}
1862 
1863 	error = 0;
1864 	hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1865 
1866 	while (pmp->inode_tid == 0) {
1867 		hammer2_xop_ipcluster_t *xop;
1868 		hammer2_inode_meta_t *meta;
1869 
1870 		xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1871 		hammer2_xop_start(&xop->head, hammer2_xop_ipcluster);
1872 		error = hammer2_xop_collect(&xop->head, 0);
1873 
1874 		if (error == 0) {
1875 			meta = &xop->head.cluster.focus->data->ipdata.meta;
1876 			pmp->iroot->meta = *meta;
1877 			pmp->inode_tid = meta->pfs_inum + 1;
1878 			if (pmp->inode_tid < HAMMER2_INODE_START)
1879 				pmp->inode_tid = HAMMER2_INODE_START;
1880 			pmp->modify_tid =
1881 				xop->head.cluster.focus->bref.modify_tid + 1;
1882 			kprintf("PFS: Starting inode %jd\n",
1883 				(intmax_t)pmp->inode_tid);
1884 			kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1885 				pmp->inode_tid, pmp->modify_tid);
1886 			wakeup(&pmp->iroot);
1887 
1888 			hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1889 
1890 			/*
1891 			 * Prime the mount info.
1892 			 */
1893 			hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
1894 			break;
1895 		}
1896 
1897 		/*
1898 		 * Loop, try again
1899 		 */
1900 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1901 		hammer2_inode_unlock(pmp->iroot);
1902 		error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
1903 		hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1904 		if (error == EINTR)
1905 			break;
1906 	}
1907 
1908 	if (error) {
1909 		hammer2_inode_unlock(pmp->iroot);
1910 		*vpp = NULL;
1911 	} else {
1912 		vp = hammer2_igetv(pmp->iroot, &error);
1913 		hammer2_inode_unlock(pmp->iroot);
1914 		*vpp = vp;
1915 	}
1916 
1917 	return (error);
1918 }
1919 
1920 /*
1921  * Filesystem status
1922  *
1923  * XXX incorporate ipdata->meta.inode_quota and data_quota
1924  */
1925 static
1926 int
1927 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
1928 {
1929 	hammer2_pfs_t *pmp;
1930 	hammer2_dev_t *hmp;
1931 	hammer2_blockref_t bref;
1932 	struct statfs tmp;
1933 	int i;
1934 
1935 	/*
1936 	 * NOTE: iroot might not have validated the cluster yet.
1937 	 */
1938 	pmp = MPTOPMP(mp);
1939 
1940 	bzero(&tmp, sizeof(tmp));
1941 
1942 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1943 		hmp = pmp->pfs_hmps[i];
1944 		if (hmp == NULL)
1945 			continue;
1946 		if (pmp->iroot->cluster.array[i].chain)
1947 			bref = pmp->iroot->cluster.array[i].chain->bref;
1948 		else
1949 			bzero(&bref, sizeof(bref));
1950 
1951 		tmp.f_files = bref.embed.stats.inode_count;
1952 		tmp.f_ffree = 0;
1953 		tmp.f_blocks = hmp->voldata.allocator_size /
1954 			       mp->mnt_vstat.f_bsize;
1955 		tmp.f_bfree = hmp->voldata.allocator_free /
1956 			      mp->mnt_vstat.f_bsize;
1957 		tmp.f_bavail = tmp.f_bfree;
1958 
1959 		if (cred && cred->cr_uid != 0) {
1960 			uint64_t adj;
1961 
1962 			/* 5% */
1963 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
1964 			tmp.f_blocks -= adj;
1965 			tmp.f_bfree -= adj;
1966 			tmp.f_bavail -= adj;
1967 		}
1968 
1969 		mp->mnt_stat.f_blocks = tmp.f_blocks;
1970 		mp->mnt_stat.f_bfree = tmp.f_bfree;
1971 		mp->mnt_stat.f_bavail = tmp.f_bavail;
1972 		mp->mnt_stat.f_files = tmp.f_files;
1973 		mp->mnt_stat.f_ffree = tmp.f_ffree;
1974 
1975 		*sbp = mp->mnt_stat;
1976 	}
1977 	return (0);
1978 }
1979 
1980 static
1981 int
1982 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
1983 {
1984 	hammer2_pfs_t *pmp;
1985 	hammer2_dev_t *hmp;
1986 	hammer2_blockref_t bref;
1987 	struct statvfs tmp;
1988 	int i;
1989 
1990 	/*
1991 	 * NOTE: iroot might not have validated the cluster yet.
1992 	 */
1993 	pmp = MPTOPMP(mp);
1994 	bzero(&tmp, sizeof(tmp));
1995 
1996 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1997 		hmp = pmp->pfs_hmps[i];
1998 		if (hmp == NULL)
1999 			continue;
2000 		if (pmp->iroot->cluster.array[i].chain)
2001 			bref = pmp->iroot->cluster.array[i].chain->bref;
2002 		else
2003 			bzero(&bref, sizeof(bref));
2004 
2005 		tmp.f_files = bref.embed.stats.inode_count;
2006 		tmp.f_ffree = 0;
2007 		tmp.f_blocks = hmp->voldata.allocator_size /
2008 			       mp->mnt_vstat.f_bsize;
2009 		tmp.f_bfree = hmp->voldata.allocator_free /
2010 			      mp->mnt_vstat.f_bsize;
2011 		tmp.f_bavail = tmp.f_bfree;
2012 
2013 		if (cred && cred->cr_uid != 0) {
2014 			uint64_t adj;
2015 
2016 			/* 5% */
2017 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2018 			tmp.f_blocks -= adj;
2019 			tmp.f_bfree -= adj;
2020 			tmp.f_bavail -= adj;
2021 		}
2022 
2023 		mp->mnt_vstat.f_blocks = tmp.f_blocks;
2024 		mp->mnt_vstat.f_bfree = tmp.f_bfree;
2025 		mp->mnt_vstat.f_bavail = tmp.f_bavail;
2026 		mp->mnt_vstat.f_files = tmp.f_files;
2027 		mp->mnt_vstat.f_ffree = tmp.f_ffree;
2028 
2029 		*sbp = mp->mnt_vstat;
2030 	}
2031 	return (0);
2032 }
2033 
2034 /*
2035  * Mount-time recovery (RW mounts)
2036  *
2037  * Updates to the free block table are allowed to lag flushes by one
2038  * transaction.  In case of a crash, then on a fresh mount we must do an
2039  * incremental scan of the last committed transaction id and make sure that
2040  * all related blocks have been marked allocated.
2041  *
2042  * The super-root topology and each PFS has its own transaction id domain,
2043  * so we must track PFS boundary transitions.
2044  */
2045 struct hammer2_recovery_elm {
2046 	TAILQ_ENTRY(hammer2_recovery_elm) entry;
2047 	hammer2_chain_t *chain;
2048 	hammer2_tid_t sync_tid;
2049 };
2050 
2051 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
2052 
2053 struct hammer2_recovery_info {
2054 	struct hammer2_recovery_list list;
2055 	hammer2_tid_t	mtid;
2056 	int	depth;
2057 };
2058 
2059 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
2060 			hammer2_chain_t *parent,
2061 			struct hammer2_recovery_info *info,
2062 			hammer2_tid_t sync_tid);
2063 
2064 #define HAMMER2_RECOVERY_MAXDEPTH	10
2065 
2066 static
2067 int
2068 hammer2_recovery(hammer2_dev_t *hmp)
2069 {
2070 	struct hammer2_recovery_info info;
2071 	struct hammer2_recovery_elm *elm;
2072 	hammer2_chain_t *parent;
2073 	hammer2_tid_t sync_tid;
2074 	hammer2_tid_t mirror_tid;
2075 	int error;
2076 
2077 	hammer2_trans_init(hmp->spmp, 0);
2078 
2079 	sync_tid = hmp->voldata.freemap_tid;
2080 	mirror_tid = hmp->voldata.mirror_tid;
2081 
2082 	kprintf("hammer2 mount \"%s\": ", hmp->devrepname);
2083 	if (sync_tid >= mirror_tid) {
2084 		kprintf(" no recovery needed\n");
2085 	} else {
2086 		kprintf(" freemap recovery %016jx-%016jx\n",
2087 			sync_tid + 1, mirror_tid);
2088 	}
2089 
2090 	TAILQ_INIT(&info.list);
2091 	info.depth = 0;
2092 	parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
2093 	error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
2094 	hammer2_chain_lookup_done(parent);
2095 
2096 	while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
2097 		TAILQ_REMOVE(&info.list, elm, entry);
2098 		parent = elm->chain;
2099 		sync_tid = elm->sync_tid;
2100 		kfree(elm, M_HAMMER2);
2101 
2102 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2103 		error |= hammer2_recovery_scan(hmp, parent, &info,
2104 					      hmp->voldata.freemap_tid);
2105 		hammer2_chain_unlock(parent);
2106 		hammer2_chain_drop(parent);	/* drop elm->chain ref */
2107 	}
2108 	hammer2_trans_done(hmp->spmp);
2109 
2110 	return error;
2111 }
2112 
2113 static
2114 int
2115 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
2116 		      struct hammer2_recovery_info *info,
2117 		      hammer2_tid_t sync_tid)
2118 {
2119 	const hammer2_inode_data_t *ripdata;
2120 	hammer2_chain_t *chain;
2121 	hammer2_blockref_t bref;
2122 	int tmp_error;
2123 	int rup_error;
2124 	int error;
2125 	int first;
2126 
2127 	/*
2128 	 * Adjust freemap to ensure that the block(s) are marked allocated.
2129 	 */
2130 	if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
2131 		hammer2_freemap_adjust(hmp, &parent->bref,
2132 				       HAMMER2_FREEMAP_DORECOVER);
2133 	}
2134 
2135 	/*
2136 	 * Check type for recursive scan
2137 	 */
2138 	switch(parent->bref.type) {
2139 	case HAMMER2_BREF_TYPE_VOLUME:
2140 		/* data already instantiated */
2141 		break;
2142 	case HAMMER2_BREF_TYPE_INODE:
2143 		/*
2144 		 * Must instantiate data for DIRECTDATA test and also
2145 		 * for recursion.
2146 		 */
2147 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2148 		ripdata = &hammer2_chain_rdata(parent)->ipdata;
2149 		if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
2150 			/* not applicable to recovery scan */
2151 			hammer2_chain_unlock(parent);
2152 			return 0;
2153 		}
2154 		hammer2_chain_unlock(parent);
2155 		break;
2156 	case HAMMER2_BREF_TYPE_INDIRECT:
2157 		/*
2158 		 * Must instantiate data for recursion
2159 		 */
2160 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2161 		hammer2_chain_unlock(parent);
2162 		break;
2163 	case HAMMER2_BREF_TYPE_DIRENT:
2164 	case HAMMER2_BREF_TYPE_DATA:
2165 	case HAMMER2_BREF_TYPE_FREEMAP:
2166 	case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2167 	case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2168 		/* not applicable to recovery scan */
2169 		return 0;
2170 		break;
2171 	default:
2172 		return HAMMER2_ERROR_BADBREF;
2173 	}
2174 
2175 	/*
2176 	 * Defer operation if depth limit reached or if we are crossing a
2177 	 * PFS boundary.
2178 	 */
2179 	if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
2180 		struct hammer2_recovery_elm *elm;
2181 
2182 		elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
2183 		elm->chain = parent;
2184 		elm->sync_tid = sync_tid;
2185 		hammer2_chain_ref(parent);
2186 		TAILQ_INSERT_TAIL(&info->list, elm, entry);
2187 		/* unlocked by caller */
2188 
2189 		return(0);
2190 	}
2191 
2192 
2193 	/*
2194 	 * Recursive scan of the last flushed transaction only.  We are
2195 	 * doing this without pmp assignments so don't leave the chains
2196 	 * hanging around after we are done with them.
2197 	 *
2198 	 * error	Cumulative error this level only
2199 	 * rup_error	Cumulative error for recursion
2200 	 * tmp_error	Specific non-cumulative recursion error
2201 	 */
2202 	chain = NULL;
2203 	first = 1;
2204 	rup_error = 0;
2205 	error = 0;
2206 
2207 	for (;;) {
2208 		error |= hammer2_chain_scan(parent, &chain, &bref,
2209 					    &first,
2210 					    HAMMER2_LOOKUP_NODATA);
2211 
2212 		/*
2213 		 * Problem during scan or EOF
2214 		 */
2215 		if (error)
2216 			break;
2217 
2218 		/*
2219 		 * If this is a leaf
2220 		 */
2221 		if (chain == NULL) {
2222 			if (bref.mirror_tid > sync_tid) {
2223 				hammer2_freemap_adjust(hmp, &bref,
2224 						     HAMMER2_FREEMAP_DORECOVER);
2225 			}
2226 			continue;
2227 		}
2228 
2229 		/*
2230 		 * This may or may not be a recursive node.
2231 		 */
2232 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
2233 		if (bref.mirror_tid > sync_tid) {
2234 			++info->depth;
2235 			tmp_error = hammer2_recovery_scan(hmp, chain,
2236 							   info, sync_tid);
2237 			--info->depth;
2238 		} else {
2239 			tmp_error = 0;
2240 		}
2241 
2242 		/*
2243 		 * Flush the recovery at the PFS boundary to stage it for
2244 		 * the final flush of the super-root topology.
2245 		 */
2246 		if (tmp_error == 0 &&
2247 		    (bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
2248 		    (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
2249 			hammer2_flush(chain, HAMMER2_FLUSH_TOP);
2250 		}
2251 		rup_error |= tmp_error;
2252 	}
2253 	return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
2254 }
2255 
2256 /*
2257  * Sync a mount point; this is called on a per-mount basis from the
2258  * filesystem syncer process periodically and whenever a user issues
2259  * a sync.
2260  */
2261 int
2262 hammer2_vfs_sync(struct mount *mp, int waitfor)
2263 {
2264 	hammer2_xop_flush_t *xop;
2265 	struct hammer2_sync_info info;
2266 	hammer2_inode_t *iroot;
2267 	hammer2_pfs_t *pmp;
2268 	int flags;
2269 	int error;
2270 
2271 	pmp = MPTOPMP(mp);
2272 	iroot = pmp->iroot;
2273 	KKASSERT(iroot);
2274 	KKASSERT(iroot->pmp == pmp);
2275 
2276 	/*
2277 	 * We can't acquire locks on existing vnodes while in a transaction
2278 	 * without risking a deadlock.  This assumes that vfsync() can be
2279 	 * called without the vnode locked (which it can in DragonFly).
2280 	 * Otherwise we'd have to implement a multi-pass or flag the lock
2281 	 * failures and retry.
2282 	 *
2283 	 * The reclamation code interlocks with the sync list's token
2284 	 * (by removing the vnode from the scan list) before unlocking
2285 	 * the inode, giving us time to ref the inode.
2286 	 */
2287 	/*flags = VMSC_GETVP;*/
2288 	flags = 0;
2289 	if (waitfor & MNT_LAZY)
2290 		flags |= VMSC_ONEPASS;
2291 
2292 	/*
2293 	 * Preflush the vnodes using a normal transaction before interlocking
2294 	 * with a flush transaction.  We do this to try to run as much of
2295 	 * the compression as possible outside the flush transaction.
2296 	 *
2297 	 * For efficiency do an async pass before making sure with a
2298 	 * synchronous pass on all related buffer cache buffers.
2299 	 */
2300 	hammer2_trans_init(pmp, 0);
2301 	info.error = 0;
2302 	info.waitfor = MNT_NOWAIT;
2303 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2304 	info.waitfor = MNT_WAIT;
2305 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2306 	hammer2_trans_done(pmp);
2307 
2308 	/*
2309 	 * Start our flush transaction.  This does not return until all
2310 	 * concurrent transactions have completed and will prevent any
2311 	 * new transactions from running concurrently, except for the
2312 	 * buffer cache transactions.
2313 	 *
2314 	 * (1) vfsync() all dirty vnodes via vfsyncscan().
2315 	 *
2316 	 * (2) Flush any remaining dirty inodes (the sideq), including any
2317 	 *     which may have been created during or raced against the
2318 	 *     vfsync().  To catch all cases this must be done after the
2319 	 *     vfsync().
2320 	 *
2321 	 * (3) Wait for any pending BIO I/O to complete (hammer2_bioq_sync()).
2322 	 *
2323 	 * NOTE! It is still possible for the paging code to push pages
2324 	 *	 out via a UIO_NOCOPY hammer2_vop_write() during the main
2325 	 *	 flush.
2326 	 */
2327 	hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
2328 
2329 	info.error = 0;
2330 	info.waitfor = MNT_NOWAIT;
2331 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2332 	info.waitfor = MNT_WAIT;
2333 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2334 	hammer2_inode_run_sideq(pmp, 1);
2335 	hammer2_bioq_sync(pmp);
2336 
2337 	/*
2338 	 * Use the XOP interface to concurrently flush all nodes to
2339 	 * synchronize the PFSROOT subtopology to the media.  A standard
2340 	 * end-of-scan ENOENT error indicates cluster sufficiency.
2341 	 *
2342 	 * Note that this flush will not be visible on crash recovery until
2343 	 * we flush the super-root topology in the next loop.
2344 	 *
2345 	 * XXX For now wait for all flushes to complete.
2346 	 */
2347 	if (iroot) {
2348 		xop = hammer2_xop_alloc(iroot, HAMMER2_XOP_MODIFYING);
2349 		hammer2_xop_start(&xop->head, hammer2_inode_xop_flush);
2350 		error = hammer2_xop_collect(&xop->head,
2351 					    HAMMER2_XOP_COLLECT_WAITALL);
2352 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2353 		if (error == HAMMER2_ERROR_ENOENT)
2354 			error = 0;
2355 		else
2356 			error = hammer2_error_to_errno(error);
2357 	} else {
2358 		error = 0;
2359 	}
2360 	hammer2_trans_done(pmp);
2361 
2362 	return (error);
2363 }
2364 
2365 /*
2366  * Sync passes.
2367  *
2368  * Note that we ignore the tranasction mtid we got above.  Instead,
2369  * each vfsync below will ultimately get its own via TRANS_BUFCACHE
2370  * transactions.
2371  */
2372 static int
2373 hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
2374 {
2375 	struct hammer2_sync_info *info = data;
2376 	hammer2_inode_t *ip;
2377 	int error;
2378 
2379 	/*
2380 	 * Degenerate cases.  Note that ip == NULL typically means the
2381 	 * syncer vnode itself and we don't want to vclrisdirty() in that
2382 	 * situation.
2383 	 */
2384 	ip = VTOI(vp);
2385 	if (ip == NULL) {
2386 		return(0);
2387 	}
2388 	if (vp->v_type == VNON || vp->v_type == VBAD) {
2389 		vclrisdirty(vp);
2390 		return(0);
2391 	}
2392 
2393 	/*
2394 	 * VOP_FSYNC will start a new transaction so replicate some code
2395 	 * here to do it inline (see hammer2_vop_fsync()).
2396 	 *
2397 	 * WARNING: The vfsync interacts with the buffer cache and might
2398 	 *          block, we can't hold the inode lock at that time.
2399 	 *	    However, we MUST ref ip before blocking to ensure that
2400 	 *	    it isn't ripped out from under us (since we do not
2401 	 *	    hold a lock on the vnode).
2402 	 */
2403 	hammer2_inode_ref(ip);
2404 	if ((ip->flags & HAMMER2_INODE_MODIFIED) ||
2405 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
2406 		vfsync(vp, info->waitfor, 1, NULL, NULL);
2407 		if (ip->flags & (HAMMER2_INODE_RESIZED |
2408 				 HAMMER2_INODE_MODIFIED)) {
2409 			hammer2_inode_lock(ip, 0);
2410 			if (ip->flags & (HAMMER2_INODE_RESIZED |
2411 					 HAMMER2_INODE_MODIFIED)) {
2412 				hammer2_inode_chain_sync(ip);
2413 			}
2414 			hammer2_inode_unlock(ip);
2415 		}
2416 	}
2417 	if ((ip->flags & HAMMER2_INODE_MODIFIED) == 0 &&
2418 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
2419 		vclrisdirty(vp);
2420 	}
2421 
2422 	hammer2_inode_drop(ip);
2423 #if 1
2424 	error = 0;
2425 	if (error)
2426 		info->error = error;
2427 #endif
2428 	return(0);
2429 }
2430 
2431 static
2432 int
2433 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2434 {
2435 	hammer2_inode_t *ip;
2436 
2437 	KKASSERT(MAXFIDSZ >= 16);
2438 	ip = VTOI(vp);
2439 	fhp->fid_len = offsetof(struct fid, fid_data[16]);
2440 	fhp->fid_ext = 0;
2441 	((hammer2_tid_t *)fhp->fid_data)[0] = ip->meta.inum;
2442 	((hammer2_tid_t *)fhp->fid_data)[1] = 0;
2443 
2444 	return 0;
2445 }
2446 
2447 static
2448 int
2449 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2450 	       struct fid *fhp, struct vnode **vpp)
2451 {
2452 	hammer2_pfs_t *pmp;
2453 	hammer2_tid_t inum;
2454 	int error;
2455 
2456 	pmp = MPTOPMP(mp);
2457 	inum = ((hammer2_tid_t *)fhp->fid_data)[0] & HAMMER2_DIRHASH_USERMSK;
2458 	if (vpp) {
2459 		if (inum == 1)
2460 			error = hammer2_vfs_root(mp, vpp);
2461 		else
2462 			error = hammer2_vfs_vget(mp, NULL, inum, vpp);
2463 	} else {
2464 		error = 0;
2465 	}
2466 	if (error)
2467 		kprintf("fhtovp: %016jx -> %p, %d\n", inum, *vpp, error);
2468 	return error;
2469 }
2470 
2471 static
2472 int
2473 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2474 		 int *exflagsp, struct ucred **credanonp)
2475 {
2476 	hammer2_pfs_t *pmp;
2477 	struct netcred *np;
2478 	int error;
2479 
2480 	pmp = MPTOPMP(mp);
2481 	np = vfs_export_lookup(mp, &pmp->export, nam);
2482 	if (np) {
2483 		*exflagsp = np->netc_exflags;
2484 		*credanonp = &np->netc_anon;
2485 		error = 0;
2486 	} else {
2487 		error = EACCES;
2488 	}
2489 	return error;
2490 }
2491 
2492 /*
2493  * Support code for hammer2_vfs_mount().  Read, verify, and install the volume
2494  * header into the HMP
2495  *
2496  * XXX read four volhdrs and use the one with the highest TID whos CRC
2497  *     matches.
2498  *
2499  * XXX check iCRCs.
2500  *
2501  * XXX For filesystems w/ less than 4 volhdrs, make sure to not write to
2502  *     nonexistant locations.
2503  *
2504  * XXX Record selected volhdr and ring updates to each of 4 volhdrs
2505  */
2506 static
2507 int
2508 hammer2_install_volume_header(hammer2_dev_t *hmp)
2509 {
2510 	hammer2_volume_data_t *vd;
2511 	struct buf *bp;
2512 	hammer2_crc32_t crc0, crc, bcrc0, bcrc;
2513 	int error_reported;
2514 	int error;
2515 	int valid;
2516 	int i;
2517 
2518 	error_reported = 0;
2519 	error = 0;
2520 	valid = 0;
2521 	bp = NULL;
2522 
2523 	/*
2524 	 * There are up to 4 copies of the volume header (syncs iterate
2525 	 * between them so there is no single master).  We don't trust the
2526 	 * volu_size field so we don't know precisely how large the filesystem
2527 	 * is, so depend on the OS to return an error if we go beyond the
2528 	 * block device's EOF.
2529 	 */
2530 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
2531 		error = bread(hmp->devvp, i * HAMMER2_ZONE_BYTES64,
2532 			      HAMMER2_VOLUME_BYTES, &bp);
2533 		if (error) {
2534 			brelse(bp);
2535 			bp = NULL;
2536 			continue;
2537 		}
2538 
2539 		vd = (struct hammer2_volume_data *) bp->b_data;
2540 		if ((vd->magic != HAMMER2_VOLUME_ID_HBO) &&
2541 		    (vd->magic != HAMMER2_VOLUME_ID_ABO)) {
2542 			brelse(bp);
2543 			bp = NULL;
2544 			continue;
2545 		}
2546 
2547 		if (vd->magic == HAMMER2_VOLUME_ID_ABO) {
2548 			/* XXX: Reversed-endianness filesystem */
2549 			kprintf("hammer2: reverse-endian filesystem detected");
2550 			brelse(bp);
2551 			bp = NULL;
2552 			continue;
2553 		}
2554 
2555 		crc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT0];
2556 		crc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC0_OFF,
2557 				      HAMMER2_VOLUME_ICRC0_SIZE);
2558 		bcrc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT1];
2559 		bcrc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC1_OFF,
2560 				       HAMMER2_VOLUME_ICRC1_SIZE);
2561 		if ((crc0 != crc) || (bcrc0 != bcrc)) {
2562 			kprintf("hammer2 volume header crc "
2563 				"mismatch copy #%d %08x/%08x\n",
2564 				i, crc0, crc);
2565 			error_reported = 1;
2566 			brelse(bp);
2567 			bp = NULL;
2568 			continue;
2569 		}
2570 		if (valid == 0 || hmp->voldata.mirror_tid < vd->mirror_tid) {
2571 			valid = 1;
2572 			hmp->voldata = *vd;
2573 			hmp->volhdrno = i;
2574 		}
2575 		brelse(bp);
2576 		bp = NULL;
2577 	}
2578 	if (valid) {
2579 		hmp->volsync = hmp->voldata;
2580 		hmp->free_reserved = hmp->voldata.allocator_size / 20;
2581 		error = 0;
2582 		if (error_reported || bootverbose || 1) { /* 1/DEBUG */
2583 			kprintf("hammer2: using volume header #%d\n",
2584 				hmp->volhdrno);
2585 		}
2586 	} else {
2587 		error = EINVAL;
2588 		kprintf("hammer2: no valid volume headers found!\n");
2589 	}
2590 	return (error);
2591 }
2592 
2593 /*
2594  * This handles hysteresis on regular file flushes.  Because the BIOs are
2595  * routed to a thread it is possible for an excessive number to build up
2596  * and cause long front-end stalls long before the runningbuffspace limit
2597  * is hit, so we implement hammer2_flush_pipe to control the
2598  * hysteresis.
2599  *
2600  * This is a particular problem when compression is used.
2601  */
2602 void
2603 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
2604 {
2605 	atomic_add_int(&pmp->count_lwinprog, 1);
2606 }
2607 
2608 void
2609 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
2610 {
2611 	int lwinprog;
2612 
2613 	lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
2614 	if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
2615 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
2616 		atomic_clear_int(&pmp->count_lwinprog,
2617 				 HAMMER2_LWINPROG_WAITING);
2618 		wakeup(&pmp->count_lwinprog);
2619 	}
2620 	if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
2621 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
2622 		atomic_clear_int(&pmp->count_lwinprog,
2623 				 HAMMER2_LWINPROG_WAITING0);
2624 		wakeup(&pmp->count_lwinprog);
2625 	}
2626 }
2627 
2628 void
2629 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
2630 {
2631 	int lwinprog;
2632 	int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
2633 				    HAMMER2_LWINPROG_WAITING0;
2634 
2635 	for (;;) {
2636 		lwinprog = pmp->count_lwinprog;
2637 		cpu_ccfence();
2638 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2639 			break;
2640 		tsleep_interlock(&pmp->count_lwinprog, 0);
2641 		atomic_set_int(&pmp->count_lwinprog, lwflag);
2642 		lwinprog = pmp->count_lwinprog;
2643 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2644 			break;
2645 		tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
2646 	}
2647 }
2648 
2649 /*
2650  * Manage excessive memory resource use for chain and related
2651  * structures.
2652  */
2653 void
2654 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
2655 {
2656 	uint32_t waiting;
2657 	uint32_t count;
2658 	uint32_t limit;
2659 #if 0
2660 	static int zzticks;
2661 #endif
2662 
2663 	/*
2664 	 * Atomic check condition and wait.  Also do an early speedup of
2665 	 * the syncer to try to avoid hitting the wait.
2666 	 */
2667 	for (;;) {
2668 		waiting = pmp->inmem_dirty_chains;
2669 		cpu_ccfence();
2670 		count = waiting & HAMMER2_DIRTYCHAIN_MASK;
2671 
2672 		limit = pmp->mp->mnt_nvnodelistsize / 10;
2673 		if (limit < hammer2_limit_dirty_chains)
2674 			limit = hammer2_limit_dirty_chains;
2675 		if (limit < 1000)
2676 			limit = 1000;
2677 
2678 #if 0
2679 		if ((int)(ticks - zzticks) > hz) {
2680 			zzticks = ticks;
2681 			kprintf("count %ld %ld\n", count, limit);
2682 		}
2683 #endif
2684 
2685 		/*
2686 		 * Block if there are too many dirty chains present, wait
2687 		 * for the flush to clean some out.
2688 		 */
2689 		if (count > limit) {
2690 			tsleep_interlock(&pmp->inmem_dirty_chains, 0);
2691 			if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2692 					       waiting,
2693 				       waiting | HAMMER2_DIRTYCHAIN_WAITING)) {
2694 				speedup_syncer(pmp->mp);
2695 				tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED,
2696 				       "chnmem", hz);
2697 			}
2698 			continue;	/* loop on success or fail */
2699 		}
2700 
2701 		/*
2702 		 * Try to start an early flush before we are forced to block.
2703 		 */
2704 		if (count > limit * 7 / 10)
2705 			speedup_syncer(pmp->mp);
2706 		break;
2707 	}
2708 }
2709 
2710 void
2711 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
2712 {
2713 	if (pmp) {
2714 		atomic_add_int(&pmp->inmem_dirty_chains, 1);
2715 	}
2716 }
2717 
2718 void
2719 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp)
2720 {
2721 	uint32_t waiting;
2722 
2723 	if (pmp) {
2724 		waiting = atomic_fetchadd_int(&pmp->inmem_dirty_chains, -1);
2725 		/* don't need --waiting to test flag */
2726 		if (waiting & HAMMER2_DIRTYCHAIN_WAITING) {
2727 			atomic_clear_int(&pmp->inmem_dirty_chains,
2728 					 HAMMER2_DIRTYCHAIN_WAITING);
2729 			wakeup(&pmp->inmem_dirty_chains);
2730 		}
2731 	}
2732 }
2733 
2734 /*
2735  * Returns 0 if the filesystem has tons of free space
2736  * Returns 1 if the filesystem has less than 10% remaining
2737  * Returns 2 if the filesystem has less than 2%/5% (user/root) remaining.
2738  */
2739 int
2740 hammer2_vfs_enospace(hammer2_inode_t *ip, off_t bytes, struct ucred *cred)
2741 {
2742 	hammer2_pfs_t *pmp;
2743 	hammer2_dev_t *hmp;
2744 	hammer2_off_t free_reserved;
2745 	hammer2_off_t free_nominal;
2746 	int i;
2747 
2748 	pmp = ip->pmp;
2749 
2750 	if (pmp->free_ticks == 0 || pmp->free_ticks != ticks) {
2751 		free_reserved = HAMMER2_SEGSIZE;
2752 		free_nominal = 0x7FFFFFFFFFFFFFFFLLU;
2753 		for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2754 			hmp = pmp->pfs_hmps[i];
2755 			if (hmp == NULL)
2756 				continue;
2757 			if (pmp->pfs_types[i] != HAMMER2_PFSTYPE_MASTER &&
2758 			    pmp->pfs_types[i] != HAMMER2_PFSTYPE_SOFT_MASTER)
2759 				continue;
2760 
2761 			if (free_nominal > hmp->voldata.allocator_free)
2762 				free_nominal = hmp->voldata.allocator_free;
2763 			if (free_reserved < hmp->free_reserved)
2764 				free_reserved = hmp->free_reserved;
2765 		}
2766 
2767 		/*
2768 		 * SMP races ok
2769 		 */
2770 		pmp->free_reserved = free_reserved;
2771 		pmp->free_nominal = free_nominal;
2772 		pmp->free_ticks = ticks;
2773 	} else {
2774 		free_reserved = pmp->free_reserved;
2775 		free_nominal = pmp->free_nominal;
2776 	}
2777 	if (cred && cred->cr_uid != 0) {
2778 		if ((int64_t)(free_nominal - bytes) <
2779 		    (int64_t)free_reserved) {
2780 			return 2;
2781 		}
2782 	} else {
2783 		if ((int64_t)(free_nominal - bytes) <
2784 		    (int64_t)free_reserved / 2) {
2785 			return 2;
2786 		}
2787 	}
2788 	if ((int64_t)(free_nominal - bytes) < (int64_t)free_reserved * 2)
2789 		return 1;
2790 	return 0;
2791 }
2792 
2793 /*
2794  * Debugging
2795  */
2796 void
2797 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int *countp, char pfx)
2798 {
2799 	hammer2_chain_t *scan;
2800 	hammer2_chain_t *parent;
2801 
2802 	--*countp;
2803 	if (*countp == 0) {
2804 		kprintf("%*.*s...\n", tab, tab, "");
2805 		return;
2806 	}
2807 	if (*countp < 0)
2808 		return;
2809 	kprintf("%*.*s%c-chain %p.%d %016jx/%d mir=%016jx\n",
2810 		tab, tab, "", pfx,
2811 		chain, chain->bref.type,
2812 		chain->bref.key, chain->bref.keybits,
2813 		chain->bref.mirror_tid);
2814 
2815 	kprintf("%*.*s      [%08x] (%s) refs=%d",
2816 		tab, tab, "",
2817 		chain->flags,
2818 		((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2819 		chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
2820 		chain->refs);
2821 
2822 	parent = chain->parent;
2823 	if (parent)
2824 		kprintf("\n%*.*s      p=%p [pflags %08x prefs %d",
2825 			tab, tab, "",
2826 			parent, parent->flags, parent->refs);
2827 	if (RB_EMPTY(&chain->core.rbtree)) {
2828 		kprintf("\n");
2829 	} else {
2830 		kprintf(" {\n");
2831 		RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree)
2832 			hammer2_dump_chain(scan, tab + 4, countp, 'a');
2833 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
2834 			kprintf("%*.*s}(%s)\n", tab, tab, "",
2835 				chain->data->ipdata.filename);
2836 		else
2837 			kprintf("%*.*s}\n", tab, tab, "");
2838 	}
2839 }
2840