xref: /dragonfly/sys/vfs/hammer2/hammer2_vfsops.c (revision c9c5aa9e)
1 /*
2  * Copyright (c) 2011-2018 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@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/mountctl.h>
51 #include <sys/dirent.h>
52 #include <sys/uio.h>
53 
54 #include "hammer2.h"
55 #include "hammer2_disk.h"
56 #include "hammer2_mount.h"
57 #include "hammer2_lz4.h"
58 
59 #include "zlib/hammer2_zlib.h"
60 
61 #define REPORT_REFS_ERRORS 1	/* XXX remove me */
62 
63 MALLOC_DEFINE(M_OBJCACHE, "objcache", "Object Cache");
64 
65 struct hammer2_sync_info {
66 	int error;
67 	int waitfor;
68 	int pass;
69 };
70 
71 TAILQ_HEAD(hammer2_mntlist, hammer2_dev);
72 static struct hammer2_mntlist hammer2_mntlist;
73 
74 struct hammer2_pfslist hammer2_pfslist;
75 struct hammer2_pfslist hammer2_spmplist;
76 struct lock hammer2_mntlk;
77 
78 int hammer2_supported_version = HAMMER2_VOL_VERSION_DEFAULT;
79 int hammer2_debug;
80 int hammer2_xopgroups;
81 long hammer2_debug_inode;
82 int hammer2_cluster_meta_read = 1;	/* physical read-ahead */
83 int hammer2_cluster_data_read = 4;	/* physical read-ahead */
84 int hammer2_cluster_write = 0;		/* physical write clustering */
85 int hammer2_dedup_enable = 1;
86 int hammer2_always_compress = 0;	/* always try to compress */
87 int hammer2_flush_pipe = 100;
88 int hammer2_dio_count;
89 int hammer2_dio_limit = 256;
90 int hammer2_bulkfree_tps = 5000;
91 int hammer2_worker_rmask = 3;
92 long hammer2_chain_allocs;
93 long hammer2_limit_dirty_chains;
94 long hammer2_limit_dirty_inodes;
95 long hammer2_count_modified_chains;
96 long hammer2_iod_file_read;
97 long hammer2_iod_meta_read;
98 long hammer2_iod_indr_read;
99 long hammer2_iod_fmap_read;
100 long hammer2_iod_volu_read;
101 long hammer2_iod_file_write;
102 long hammer2_iod_file_wembed;
103 long hammer2_iod_file_wzero;
104 long hammer2_iod_file_wdedup;
105 long hammer2_iod_meta_write;
106 long hammer2_iod_indr_write;
107 long hammer2_iod_fmap_write;
108 long hammer2_iod_volu_write;
109 static long hammer2_iod_inode_creates;
110 static long hammer2_iod_inode_deletes;
111 
112 long hammer2_process_icrc32;
113 long hammer2_process_xxhash64;
114 
115 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
116 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
117 		"Buffer used for compression.");
118 
119 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
120 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
121 		"Buffer used for decompression.");
122 
123 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
124 
125 SYSCTL_INT(_vfs_hammer2, OID_AUTO, supported_version, CTLFLAG_RD,
126 	   &hammer2_supported_version, 0, "");
127 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
128 	   &hammer2_debug, 0, "");
129 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, debug_inode, CTLFLAG_RW,
130 	   &hammer2_debug_inode, 0, "");
131 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_meta_read, CTLFLAG_RW,
132 	   &hammer2_cluster_meta_read, 0, "");
133 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_data_read, CTLFLAG_RW,
134 	   &hammer2_cluster_data_read, 0, "");
135 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_write, CTLFLAG_RW,
136 	   &hammer2_cluster_write, 0, "");
137 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dedup_enable, CTLFLAG_RW,
138 	   &hammer2_dedup_enable, 0, "");
139 SYSCTL_INT(_vfs_hammer2, OID_AUTO, always_compress, CTLFLAG_RW,
140 	   &hammer2_always_compress, 0, "");
141 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
142 	   &hammer2_flush_pipe, 0, "");
143 SYSCTL_INT(_vfs_hammer2, OID_AUTO, worker_rmask, CTLFLAG_RW,
144 	   &hammer2_worker_rmask, 0, "");
145 SYSCTL_INT(_vfs_hammer2, OID_AUTO, bulkfree_tps, CTLFLAG_RW,
146 	   &hammer2_bulkfree_tps, 0, "");
147 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_allocs, CTLFLAG_RW,
148 	   &hammer2_chain_allocs, 0, "");
149 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
150 	   &hammer2_limit_dirty_chains, 0, "");
151 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_inodes, CTLFLAG_RW,
152 	   &hammer2_limit_dirty_inodes, 0, "");
153 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, count_modified_chains, CTLFLAG_RW,
154 	   &hammer2_count_modified_chains, 0, "");
155 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
156 	   &hammer2_dio_count, 0, "");
157 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_limit, CTLFLAG_RW,
158 	   &hammer2_dio_limit, 0, "");
159 
160 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
161 	   &hammer2_iod_file_read, 0, "");
162 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
163 	   &hammer2_iod_meta_read, 0, "");
164 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
165 	   &hammer2_iod_indr_read, 0, "");
166 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
167 	   &hammer2_iod_fmap_read, 0, "");
168 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
169 	   &hammer2_iod_volu_read, 0, "");
170 
171 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
172 	   &hammer2_iod_file_write, 0, "");
173 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
174 	   &hammer2_iod_file_wembed, 0, "");
175 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
176 	   &hammer2_iod_file_wzero, 0, "");
177 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
178 	   &hammer2_iod_file_wdedup, 0, "");
179 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
180 	   &hammer2_iod_meta_write, 0, "");
181 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
182 	   &hammer2_iod_indr_write, 0, "");
183 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
184 	   &hammer2_iod_fmap_write, 0, "");
185 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
186 	   &hammer2_iod_volu_write, 0, "");
187 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_inode_creates, CTLFLAG_RW,
188 	   &hammer2_iod_inode_creates, 0, "");
189 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_inode_deletes, CTLFLAG_RW,
190 	   &hammer2_iod_inode_deletes, 0, "");
191 
192 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, process_icrc32, CTLFLAG_RW,
193 	   &hammer2_process_icrc32, 0, "");
194 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, process_xxhash64, CTLFLAG_RW,
195 	   &hammer2_process_xxhash64, 0, "");
196 
197 static int hammer2_vfs_init(struct vfsconf *conf);
198 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
199 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
200 				struct ucred *cred);
201 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
202 				struct vnode *, struct ucred *);
203 static int hammer2_recovery(hammer2_dev_t *hmp);
204 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
205 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
206 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
207 				struct ucred *cred);
208 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
209 				struct ucred *cred);
210 static int hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
211 				struct fid *fhp, struct vnode **vpp);
212 static int hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp);
213 static int hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
214 				int *exflagsp, struct ucred **credanonp);
215 static int hammer2_vfs_modifying(struct mount *mp);
216 
217 static int hammer2_install_volume_header(hammer2_dev_t *hmp);
218 
219 static void hammer2_update_pmps(hammer2_dev_t *hmp);
220 
221 static void hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp);
222 static void hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp,
223 				hammer2_dev_t *hmp);
224 static int hammer2_fixup_pfses(hammer2_dev_t *hmp);
225 
226 /*
227  * HAMMER2 vfs operations.
228  */
229 static struct vfsops hammer2_vfsops = {
230 	.vfs_flags	= 0,
231 	.vfs_init	= hammer2_vfs_init,
232 	.vfs_uninit	= hammer2_vfs_uninit,
233 	.vfs_sync	= hammer2_vfs_sync,
234 	.vfs_mount	= hammer2_vfs_mount,
235 	.vfs_unmount	= hammer2_vfs_unmount,
236 	.vfs_root 	= hammer2_vfs_root,
237 	.vfs_statfs	= hammer2_vfs_statfs,
238 	.vfs_statvfs	= hammer2_vfs_statvfs,
239 	.vfs_vget	= hammer2_vfs_vget,
240 	.vfs_vptofh	= hammer2_vfs_vptofh,
241 	.vfs_fhtovp	= hammer2_vfs_fhtovp,
242 	.vfs_checkexp	= hammer2_vfs_checkexp,
243 	.vfs_modifying	= hammer2_vfs_modifying
244 };
245 
246 MALLOC_DEFINE(M_HAMMER2, "HAMMER2-mount", "");
247 
248 VFS_SET(hammer2_vfsops, hammer2, VFCF_MPSAFE);
249 MODULE_VERSION(hammer2, 1);
250 
251 static
252 int
253 hammer2_vfs_init(struct vfsconf *conf)
254 {
255 	static struct objcache_malloc_args margs_read;
256 	static struct objcache_malloc_args margs_write;
257 	static struct objcache_malloc_args margs_vop;
258 
259 	int error;
260 
261 	error = 0;
262 	kmalloc_raise_limit(M_HAMMER2, 0);	/* unlimited */
263 
264 	/*
265 	 * hammer2_xopgroups must be even and is most optimal if
266 	 * 2 x ncpus so strategy functions can be queued to the same
267 	 * cpu.
268 	 */
269 	hammer2_xopgroups = HAMMER2_XOPGROUPS_MIN;
270 	if (hammer2_xopgroups < ncpus * 2)
271 		hammer2_xopgroups = ncpus * 2;
272 
273 	/*
274 	 * A large DIO cache is needed to retain dedup enablement masks.
275 	 * The bulkfree code clears related masks as part of the disk block
276 	 * recycling algorithm, preventing it from being used for a later
277 	 * dedup.
278 	 *
279 	 * NOTE: A large buffer cache can actually interfere with dedup
280 	 *	 operation because we dedup based on media physical buffers
281 	 *	 and not logical buffers.  Try to make the DIO case large
282 	 *	 enough to avoid this problem, but also cap it.
283 	 */
284 	hammer2_dio_limit = nbuf * 2;
285 	if (hammer2_dio_limit > 100000)
286 		hammer2_dio_limit = 100000;
287 
288 	if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
289 		error = EINVAL;
290 	if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
291 		error = EINVAL;
292 	if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
293 		error = EINVAL;
294 
295 	if (error)
296 		kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
297 
298 	margs_read.objsize = 65536;
299 	margs_read.mtype = M_HAMMER2_DEBUFFER;
300 
301 	margs_write.objsize = 32768;
302 	margs_write.mtype = M_HAMMER2_CBUFFER;
303 
304 	margs_vop.objsize = sizeof(hammer2_xop_t);
305 	margs_vop.mtype = M_HAMMER2;
306 
307 	/*
308 	 * Note thaht for the XOPS cache we want backing store allocations
309 	 * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
310 	 * confusion), so use the backing store function that does it.  This
311 	 * means that initial XOPS objects are zerod but REUSED objects are
312 	 * not.  So we are responsible for cleaning the object up sufficiently
313 	 * for our needs before objcache_put()ing it back (typically just the
314 	 * FIFO indices).
315 	 */
316 	cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
317 				0, 1, NULL, NULL, NULL,
318 				objcache_malloc_alloc,
319 				objcache_malloc_free,
320 				&margs_read);
321 	cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
322 				0, 1, NULL, NULL, NULL,
323 				objcache_malloc_alloc,
324 				objcache_malloc_free,
325 				&margs_write);
326 	cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
327 				0, 1, NULL, NULL, NULL,
328 				objcache_malloc_alloc_zero,
329 				objcache_malloc_free,
330 				&margs_vop);
331 
332 
333 	lockinit(&hammer2_mntlk, "mntlk", 0, 0);
334 	TAILQ_INIT(&hammer2_mntlist);
335 	TAILQ_INIT(&hammer2_pfslist);
336 	TAILQ_INIT(&hammer2_spmplist);
337 
338 	hammer2_limit_dirty_chains = maxvnodes / 10;
339 	if (hammer2_limit_dirty_chains > HAMMER2_LIMIT_DIRTY_CHAINS)
340 		hammer2_limit_dirty_chains = HAMMER2_LIMIT_DIRTY_CHAINS;
341 	if (hammer2_limit_dirty_chains < 1000)
342 		hammer2_limit_dirty_chains = 1000;
343 
344 	hammer2_limit_dirty_inodes = maxvnodes / 25;
345 	if (hammer2_limit_dirty_inodes < 100)
346 		hammer2_limit_dirty_inodes = 100;
347 	if (hammer2_limit_dirty_inodes > HAMMER2_LIMIT_DIRTY_INODES)
348 		hammer2_limit_dirty_inodes = HAMMER2_LIMIT_DIRTY_INODES;
349 
350 	return (error);
351 }
352 
353 static
354 int
355 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
356 {
357 	objcache_destroy(cache_buffer_read);
358 	objcache_destroy(cache_buffer_write);
359 	objcache_destroy(cache_xops);
360 	return 0;
361 }
362 
363 /*
364  * Core PFS allocator.  Used to allocate or reference the pmp structure
365  * for PFS cluster mounts and the spmp structure for media (hmp) structures.
366  * The pmp can be passed in or loaded by this function using the chain and
367  * inode data.
368  *
369  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
370  * transactions.  Note that synchronization does not use this field.
371  * (typically frontend operations and synchronization cannot run on the
372  * same PFS node at the same time).
373  *
374  * XXX check locking
375  */
376 hammer2_pfs_t *
377 hammer2_pfsalloc(hammer2_chain_t *chain,
378 		 const hammer2_inode_data_t *ripdata,
379 		 hammer2_tid_t modify_tid, hammer2_dev_t *force_local)
380 {
381 	hammer2_pfs_t *pmp;
382 	hammer2_inode_t *iroot;
383 	int count;
384 	int i;
385 	int j;
386 
387 	pmp = NULL;
388 
389 	/*
390 	 * Locate or create the PFS based on the cluster id.  If ripdata
391 	 * is NULL this is a spmp which is unique and is always allocated.
392 	 *
393 	 * If the device is mounted in local mode all PFSs are considered
394 	 * independent and not part of any cluster (for debugging only).
395 	 */
396 	if (ripdata) {
397 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
398 			if (force_local != pmp->force_local)
399 				continue;
400 			if (force_local == NULL &&
401 			    bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
402 				 sizeof(pmp->pfs_clid)) == 0) {
403 					break;
404 			} else if (force_local && pmp->pfs_names[0] &&
405 			    strcmp(pmp->pfs_names[0], ripdata->filename) == 0) {
406 					break;
407 			}
408 		}
409 	}
410 
411 	if (pmp == NULL) {
412 		pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
413 		pmp->force_local = force_local;
414 		hammer2_trans_manage_init(pmp);
415 		kmalloc_create(&pmp->minode, "HAMMER2-inodes");
416 		kmalloc_create(&pmp->mmsg, "HAMMER2-pfsmsg");
417 		lockinit(&pmp->lock, "pfslk", 0, 0);
418 		lockinit(&pmp->lock_nlink, "h2nlink", 0, 0);
419 		spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
420 		spin_init(&pmp->xop_spin, "h2xop");
421 		spin_init(&pmp->lru_spin, "h2lru");
422 		RB_INIT(&pmp->inum_tree);
423 		TAILQ_INIT(&pmp->syncq);
424 		TAILQ_INIT(&pmp->depq);
425 		TAILQ_INIT(&pmp->lru_list);
426 		spin_init(&pmp->list_spin, "h2pfsalloc_list");
427 
428 		/*
429 		 * Save the last media transaction id for the flusher.  Set
430 		 * initial
431 		 */
432 		if (ripdata) {
433 			pmp->pfs_clid = ripdata->meta.pfs_clid;
434 			TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
435 		} else {
436 			pmp->flags |= HAMMER2_PMPF_SPMP;
437 			TAILQ_INSERT_TAIL(&hammer2_spmplist, pmp, mntentry);
438 		}
439 
440 		/*
441 		 * The synchronization thread may start too early, make
442 		 * sure it stays frozen until we are ready to let it go.
443 		 * XXX
444 		 */
445 		/*
446 		pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
447 					 HAMMER2_THREAD_REMASTER;
448 		*/
449 	}
450 
451 	/*
452 	 * Create the PFS's root inode and any missing XOP helper threads.
453 	 */
454 	if ((iroot = pmp->iroot) == NULL) {
455 		iroot = hammer2_inode_get(pmp, NULL, 1, -1);
456 		if (ripdata)
457 			iroot->meta = ripdata->meta;
458 		pmp->iroot = iroot;
459 		hammer2_inode_ref(iroot);
460 		hammer2_inode_unlock(iroot);
461 	}
462 
463 	/*
464 	 * Stop here if no chain is passed in.
465 	 */
466 	if (chain == NULL)
467 		goto done;
468 
469 	/*
470 	 * When a chain is passed in we must add it to the PFS's root
471 	 * inode, update pmp->pfs_types[], and update the syncronization
472 	 * threads.
473 	 *
474 	 * When forcing local mode, mark the PFS as a MASTER regardless.
475 	 *
476 	 * At the moment empty spots can develop due to removals or failures.
477 	 * Ultimately we want to re-fill these spots but doing so might
478 	 * confused running code. XXX
479 	 */
480 	hammer2_inode_ref(iroot);
481 	hammer2_mtx_ex(&iroot->lock);
482 	j = iroot->cluster.nchains;
483 
484 	if (j == HAMMER2_MAXCLUSTER) {
485 		kprintf("hammer2_pfsalloc: cluster full!\n");
486 		/* XXX fatal error? */
487 	} else {
488 		KKASSERT(chain->pmp == NULL);
489 		chain->pmp = pmp;
490 		hammer2_chain_ref(chain);
491 		iroot->cluster.array[j].chain = chain;
492 		if (force_local)
493 			pmp->pfs_types[j] = HAMMER2_PFSTYPE_MASTER;
494 		else
495 			pmp->pfs_types[j] = ripdata->meta.pfs_type;
496 		pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
497 		pmp->pfs_hmps[j] = chain->hmp;
498 		hammer2_spin_ex(&pmp->inum_spin);
499 		pmp->pfs_iroot_blocksets[j] = chain->data->ipdata.u.blockset;
500 		hammer2_spin_unex(&pmp->inum_spin);
501 
502 		/*
503 		 * If the PFS is already mounted we must account
504 		 * for the mount_count here.
505 		 */
506 		if (pmp->mp)
507 			++chain->hmp->mount_count;
508 
509 		/*
510 		 * May have to fixup dirty chain tracking.  Previous
511 		 * pmp was NULL so nothing to undo.
512 		 */
513 		if (chain->flags & HAMMER2_CHAIN_MODIFIED)
514 			hammer2_pfs_memory_inc(pmp);
515 		++j;
516 	}
517 	iroot->cluster.nchains = j;
518 
519 	/*
520 	 * Update nmasters from any PFS inode which is part of the cluster.
521 	 * It is possible that this will result in a value which is too
522 	 * high.  MASTER PFSs are authoritative for pfs_nmasters and will
523 	 * override this value later on.
524 	 *
525 	 * (This informs us of masters that might not currently be
526 	 *  discoverable by this mount).
527 	 */
528 	if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
529 		pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
530 	}
531 
532 	/*
533 	 * Count visible masters.  Masters are usually added with
534 	 * ripdata->meta.pfs_nmasters set to 1.  This detects when there
535 	 * are more (XXX and must update the master inodes).
536 	 */
537 	count = 0;
538 	for (i = 0; i < iroot->cluster.nchains; ++i) {
539 		if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
540 			++count;
541 	}
542 	if (pmp->pfs_nmasters < count)
543 		pmp->pfs_nmasters = count;
544 
545 	/*
546 	 * Create missing synchronization and support threads.
547 	 *
548 	 * Single-node masters (including snapshots) have nothing to
549 	 * synchronize and do not require this thread.
550 	 *
551 	 * Multi-node masters or any number of soft masters, slaves, copy,
552 	 * or other PFS types need the thread.
553 	 *
554 	 * Each thread is responsible for its particular cluster index.
555 	 * We use independent threads so stalls or mismatches related to
556 	 * any given target do not affect other targets.
557 	 */
558 	for (i = 0; i < iroot->cluster.nchains; ++i) {
559 		/*
560 		 * Single-node masters (including snapshots) have nothing
561 		 * to synchronize and will make direct xops support calls,
562 		 * thus they do not require this thread.
563 		 *
564 		 * Note that there can be thousands of snapshots.  We do not
565 		 * want to create thousands of threads.
566 		 */
567 		if (pmp->pfs_nmasters <= 1 &&
568 		    pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
569 			continue;
570 		}
571 
572 		/*
573 		 * Sync support thread
574 		 */
575 		if (pmp->sync_thrs[i].td == NULL) {
576 			hammer2_thr_create(&pmp->sync_thrs[i], pmp, NULL,
577 					   "h2nod", i, -1,
578 					   hammer2_primary_sync_thread);
579 		}
580 	}
581 
582 	/*
583 	 * Create missing Xop threads
584 	 *
585 	 * NOTE: We create helper threads for all mounted PFSs or any
586 	 *	 PFSs with 2+ nodes (so the sync thread can update them,
587 	 *	 even if not mounted).
588 	 */
589 	if (pmp->mp || iroot->cluster.nchains >= 2)
590 		hammer2_xop_helper_create(pmp);
591 
592 	hammer2_mtx_unlock(&iroot->lock);
593 	hammer2_inode_drop(iroot);
594 done:
595 	return pmp;
596 }
597 
598 /*
599  * Deallocate an element of a probed PFS.  If destroying and this is a
600  * MASTER, adjust nmasters.
601  *
602  * This function does not physically destroy the PFS element in its device
603  * under the super-root  (see hammer2_ioctl_pfs_delete()).
604  */
605 void
606 hammer2_pfsdealloc(hammer2_pfs_t *pmp, int clindex, int destroying)
607 {
608 	hammer2_inode_t *iroot;
609 	hammer2_chain_t *chain;
610 	int j;
611 
612 	/*
613 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
614 	 * by the flush code.
615 	 */
616 	iroot = pmp->iroot;
617 	if (iroot) {
618 		/*
619 		 * Stop synchronizing
620 		 *
621 		 * XXX flush after acquiring the iroot lock.
622 		 * XXX clean out the cluster index from all inode structures.
623 		 */
624 		hammer2_thr_delete(&pmp->sync_thrs[clindex]);
625 
626 		/*
627 		 * Remove the cluster index from the group.  If destroying
628 		 * the PFS and this is a master, adjust pfs_nmasters.
629 		 */
630 		hammer2_mtx_ex(&iroot->lock);
631 		chain = iroot->cluster.array[clindex].chain;
632 		iroot->cluster.array[clindex].chain = NULL;
633 
634 		switch(pmp->pfs_types[clindex]) {
635 		case HAMMER2_PFSTYPE_MASTER:
636 			if (destroying && pmp->pfs_nmasters > 0)
637 				--pmp->pfs_nmasters;
638 			/* XXX adjust ripdata->meta.pfs_nmasters */
639 			break;
640 		default:
641 			break;
642 		}
643 		pmp->pfs_types[clindex] = HAMMER2_PFSTYPE_NONE;
644 
645 		hammer2_mtx_unlock(&iroot->lock);
646 
647 		/*
648 		 * Release the chain.
649 		 */
650 		if (chain) {
651 			atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
652 			hammer2_chain_drop(chain);
653 		}
654 
655 		/*
656 		 * Terminate all XOP threads for the cluster index.
657 		 */
658 		if (pmp->xop_groups) {
659 			for (j = 0; j < hammer2_xopgroups; ++j) {
660 				hammer2_thr_delete(
661 					&pmp->xop_groups[j].thrs[clindex]);
662 			}
663 		}
664 	}
665 }
666 
667 /*
668  * Destroy a PFS, typically only occurs after the last mount on a device
669  * has gone away.
670  */
671 static void
672 hammer2_pfsfree(hammer2_pfs_t *pmp)
673 {
674 	hammer2_inode_t *iroot;
675 	hammer2_chain_t *chain;
676 	int chains_still_present = 0;
677 	int i;
678 	int j;
679 
680 	/*
681 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
682 	 * by the flush code.
683 	 */
684 	if (pmp->flags & HAMMER2_PMPF_SPMP)
685 		TAILQ_REMOVE(&hammer2_spmplist, pmp, mntentry);
686 	else
687 		TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
688 
689 	/*
690 	 * Cleanup chains remaining on LRU list.
691 	 */
692 	hammer2_spin_ex(&pmp->lru_spin);
693 	while ((chain = TAILQ_FIRST(&pmp->lru_list)) != NULL) {
694 		KKASSERT(chain->flags & HAMMER2_CHAIN_ONLRU);
695 		atomic_add_int(&pmp->lru_count, -1);
696 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
697 		TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
698 		hammer2_chain_ref(chain);
699 		hammer2_spin_unex(&pmp->lru_spin);
700 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
701 		hammer2_chain_drop(chain);
702 		hammer2_spin_ex(&pmp->lru_spin);
703 	}
704 	hammer2_spin_unex(&pmp->lru_spin);
705 
706 	/*
707 	 * Clean up iroot
708 	 */
709 	iroot = pmp->iroot;
710 	if (iroot) {
711 		for (i = 0; i < iroot->cluster.nchains; ++i) {
712 			hammer2_thr_delete(&pmp->sync_thrs[i]);
713 			if (pmp->xop_groups) {
714 				for (j = 0; j < hammer2_xopgroups; ++j)
715 					hammer2_thr_delete(
716 						&pmp->xop_groups[j].thrs[i]);
717 			}
718 			chain = iroot->cluster.array[i].chain;
719 			if (chain && !RB_EMPTY(&chain->core.rbtree)) {
720 				kprintf("hammer2: Warning pmp %p still "
721 					"has active chains\n", pmp);
722 				chains_still_present = 1;
723 			}
724 		}
725 #if REPORT_REFS_ERRORS
726 		if (iroot->refs != 1)
727 			kprintf("PMP->IROOT %p REFS WRONG %d\n",
728 				iroot, iroot->refs);
729 #else
730 		KKASSERT(iroot->refs == 1);
731 #endif
732 		/* ref for iroot */
733 		hammer2_inode_drop(iroot);
734 		pmp->iroot = NULL;
735 	}
736 
737 	/*
738 	 * Free remaining pmp resources
739 	 */
740 	if (chains_still_present) {
741 		kprintf("hammer2: cannot free pmp %p, still in use\n", pmp);
742 	} else {
743 		kmalloc_destroy(&pmp->mmsg);
744 		kmalloc_destroy(&pmp->minode);
745 		kfree(pmp, M_HAMMER2);
746 	}
747 }
748 
749 /*
750  * Remove all references to hmp from the pfs list.  Any PFS which becomes
751  * empty is terminated and freed.
752  *
753  * XXX inefficient.
754  */
755 static void
756 hammer2_pfsfree_scan(hammer2_dev_t *hmp, int which)
757 {
758 	hammer2_pfs_t *pmp;
759 	hammer2_inode_t *iroot;
760 	hammer2_chain_t *rchain;
761 	int i;
762 	int j;
763 	struct hammer2_pfslist *wlist;
764 
765 	if (which == 0)
766 		wlist = &hammer2_pfslist;
767 	else
768 		wlist = &hammer2_spmplist;
769 again:
770 	TAILQ_FOREACH(pmp, wlist, mntentry) {
771 		if ((iroot = pmp->iroot) == NULL)
772 			continue;
773 
774 		/*
775 		 * Determine if this PFS is affected.  If it is we must
776 		 * freeze all management threads and lock its iroot.
777 		 *
778 		 * Freezing a management thread forces it idle, operations
779 		 * in-progress will be aborted and it will have to start
780 		 * over again when unfrozen, or exit if told to exit.
781 		 */
782 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
783 			if (pmp->pfs_hmps[i] == hmp)
784 				break;
785 		}
786 		if (i == HAMMER2_MAXCLUSTER)
787 			continue;
788 
789 		hammer2_vfs_sync_pmp(pmp, MNT_WAIT);
790 
791 		/*
792 		 * Make sure all synchronization threads are locked
793 		 * down.
794 		 */
795 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
796 			if (pmp->pfs_hmps[i] == NULL)
797 				continue;
798 			hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
799 			if (pmp->xop_groups) {
800 				for (j = 0; j < hammer2_xopgroups; ++j) {
801 					hammer2_thr_freeze_async(
802 						&pmp->xop_groups[j].thrs[i]);
803 				}
804 			}
805 		}
806 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
807 			if (pmp->pfs_hmps[i] == NULL)
808 				continue;
809 			hammer2_thr_freeze(&pmp->sync_thrs[i]);
810 			if (pmp->xop_groups) {
811 				for (j = 0; j < hammer2_xopgroups; ++j) {
812 					hammer2_thr_freeze(
813 						&pmp->xop_groups[j].thrs[i]);
814 				}
815 			}
816 		}
817 
818 		/*
819 		 * Lock the inode and clean out matching chains.
820 		 * Note that we cannot use hammer2_inode_lock_*()
821 		 * here because that would attempt to validate the
822 		 * cluster that we are in the middle of ripping
823 		 * apart.
824 		 *
825 		 * WARNING! We are working directly on the inodes
826 		 *	    embedded cluster.
827 		 */
828 		hammer2_mtx_ex(&iroot->lock);
829 
830 		/*
831 		 * Remove the chain from matching elements of the PFS.
832 		 */
833 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
834 			if (pmp->pfs_hmps[i] != hmp)
835 				continue;
836 			hammer2_thr_delete(&pmp->sync_thrs[i]);
837 			if (pmp->xop_groups) {
838 				for (j = 0; j < hammer2_xopgroups; ++j) {
839 					hammer2_thr_delete(
840 						&pmp->xop_groups[j].thrs[i]);
841 				}
842 			}
843 			rchain = iroot->cluster.array[i].chain;
844 			iroot->cluster.array[i].chain = NULL;
845 			pmp->pfs_types[i] = 0;
846 			if (pmp->pfs_names[i]) {
847 				kfree(pmp->pfs_names[i], M_HAMMER2);
848 				pmp->pfs_names[i] = NULL;
849 			}
850 			if (rchain) {
851 				hammer2_chain_drop(rchain);
852 				/* focus hint */
853 				if (iroot->cluster.focus == rchain)
854 					iroot->cluster.focus = NULL;
855 			}
856 			pmp->pfs_hmps[i] = NULL;
857 		}
858 		hammer2_mtx_unlock(&iroot->lock);
859 
860 		/*
861 		 * Cleanup trailing chains.  Gaps may remain.
862 		 */
863 		for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
864 			if (pmp->pfs_hmps[i])
865 				break;
866 		}
867 		iroot->cluster.nchains = i + 1;
868 
869 		/*
870 		 * If the PMP has no elements remaining we can destroy it.
871 		 * (this will transition management threads from frozen->exit).
872 		 */
873 		if (iroot->cluster.nchains == 0) {
874 			/*
875 			 * If this was the hmp's spmp, we need to clean
876 			 * a little more stuff out.
877 			 */
878 			if (hmp->spmp == pmp) {
879 				hmp->spmp = NULL;
880 				hmp->vchain.pmp = NULL;
881 				hmp->fchain.pmp = NULL;
882 			}
883 
884 			/*
885 			 * Free the pmp and restart the loop
886 			 */
887 			KKASSERT(TAILQ_EMPTY(&pmp->syncq));
888 			KKASSERT(TAILQ_EMPTY(&pmp->depq));
889 			hammer2_pfsfree(pmp);
890 			goto again;
891 		}
892 
893 		/*
894 		 * If elements still remain we need to set the REMASTER
895 		 * flag and unfreeze it.
896 		 */
897 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
898 			if (pmp->pfs_hmps[i] == NULL)
899 				continue;
900 			hammer2_thr_remaster(&pmp->sync_thrs[i]);
901 			hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
902 			if (pmp->xop_groups) {
903 				for (j = 0; j < hammer2_xopgroups; ++j) {
904 					hammer2_thr_remaster(
905 						&pmp->xop_groups[j].thrs[i]);
906 					hammer2_thr_unfreeze(
907 						&pmp->xop_groups[j].thrs[i]);
908 				}
909 			}
910 		}
911 	}
912 }
913 
914 /*
915  * Mount or remount HAMMER2 fileystem from physical media
916  *
917  *	mountroot
918  *		mp		mount point structure
919  *		path		NULL
920  *		data		<unused>
921  *		cred		<unused>
922  *
923  *	mount
924  *		mp		mount point structure
925  *		path		path to mount point
926  *		data		pointer to argument structure in user space
927  *			volume	volume path (device@LABEL form)
928  *			hflags	user mount flags
929  *		cred		user credentials
930  *
931  * RETURNS:	0	Success
932  *		!0	error number
933  */
934 static
935 int
936 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
937 		  struct ucred *cred)
938 {
939 	struct hammer2_mount_info info;
940 	hammer2_pfs_t *pmp;
941 	hammer2_pfs_t *spmp;
942 	hammer2_dev_t *hmp;
943 	hammer2_dev_t *force_local;
944 	hammer2_key_t key_next;
945 	hammer2_key_t key_dummy;
946 	hammer2_key_t lhc;
947 	struct vnode *devvp;
948 	struct nlookupdata nd;
949 	hammer2_chain_t *parent;
950 	hammer2_chain_t *chain;
951 	const hammer2_inode_data_t *ripdata;
952 	hammer2_blockref_t bref;
953 	struct file *fp;
954 	char devstr[MNAMELEN];
955 	size_t size;
956 	size_t done;
957 	char *dev;
958 	char *label;
959 	int ronly = 1;
960 	int error;
961 	int i;
962 
963 	hmp = NULL;
964 	pmp = NULL;
965 	dev = NULL;
966 	label = NULL;
967 	devvp = NULL;
968 	bzero(&info, sizeof(info));
969 
970 	if (path) {
971 		/*
972 		 * Non-root mount or updating a mount
973 		 */
974 		error = copyin(data, &info, sizeof(info));
975 		if (error)
976 			return (error);
977 	}
978 
979 	if (mp->mnt_flag & MNT_UPDATE) {
980 		/*
981 		 * Update mount.  Note that pmp->iroot->cluster is
982 		 * an inode-embedded cluster and thus cannot be
983 		 * directly locked.
984 		 *
985 		 * XXX HAMMER2 needs to implement NFS export via
986 		 *     mountctl.
987 		 */
988 		hammer2_cluster_t *cluster;
989 
990 		pmp = MPTOPMP(mp);
991 		pmp->hflags = info.hflags;
992 		cluster = &pmp->iroot->cluster;
993 		for (i = 0; i < cluster->nchains; ++i) {
994 			if (cluster->array[i].chain == NULL)
995 				continue;
996 			hmp = cluster->array[i].chain->hmp;
997 			devvp = hmp->devvp;
998 			error = hammer2_remount(hmp, mp, path,
999 						devvp, cred);
1000 			if (error)
1001 				break;
1002 		}
1003 
1004 		return error;
1005 	}
1006 
1007 	if (path == NULL) {
1008 		/*
1009 		 * Root mount
1010 		 */
1011 		info.cluster_fd = -1;
1012 		ksnprintf(devstr, sizeof(devstr), "%s",
1013 			  mp->mnt_stat.f_mntfromname);
1014 		done = strlen(devstr) + 1;
1015 		kprintf("hammer2_mount: root devstr=\"%s\"\n", devstr);
1016 	} else {
1017 		error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
1018 		if (error)
1019 			return (error);
1020 		kprintf("hammer2_mount: devstr=\"%s\"\n", devstr);
1021 	}
1022 
1023 	/*
1024 	 * Extract device and label, automatically mount @BOOT, @ROOT, or @DATA
1025 	 * if no label specified, based on the partition id.  Error out if no
1026 	 * label or device (with partition id) is specified.  This is strictly
1027 	 * a convenience to match the default label created by newfs_hammer2,
1028 	 * our preference is that a label always be specified.
1029 	 *
1030 	 * NOTE: We allow 'mount @LABEL <blah>'... that is, a mount command
1031 	 *	 that does not specify a device, as long as some H2 label
1032 	 *	 has already been mounted from that device.  This makes
1033 	 *	 mounting snapshots a lot easier.
1034 	 */
1035 	dev = devstr;
1036 	label = strchr(devstr, '@');
1037 	if (label && ((label + 1) - dev) > done) {
1038 		kprintf("hammer2_mount: bad label %s/%zd\n", devstr, done);
1039 		return (EINVAL);
1040 	}
1041 	if (label == NULL || label[1] == 0) {
1042 		char slice;
1043 
1044 		if (label == NULL)
1045 			label = devstr + strlen(devstr);
1046 		else
1047 			*label = '\0';		/* clean up trailing @ */
1048 
1049 		slice = label[-1];
1050 		switch(slice) {
1051 		case 'a':
1052 			label = "BOOT";
1053 			break;
1054 		case 'd':
1055 			label = "ROOT";
1056 			break;
1057 		default:
1058 			label = "DATA";
1059 			break;
1060 		}
1061 	} else {
1062 		*label = '\0';
1063 		label++;
1064 	}
1065 
1066 	kprintf("hammer2_mount: dev=\"%s\" label=\"%s\" rdonly=%d\n",
1067 		dev, label, (mp->mnt_flag & MNT_RDONLY));
1068 
1069 	/*
1070 	 * HMP device mount
1071 	 *
1072 	 * If a path is specified and dev is not an empty string, lookup the
1073 	 * name and verify that it referes to a block device.
1074 	 *
1075 	 * If a path is specified and dev is an empty string we fall through
1076 	 * and locate the label in the hmp search.
1077 	 */
1078 	if (path && *dev != 0) {
1079 		error = nlookup_init(&nd, dev, UIO_SYSSPACE, NLC_FOLLOW);
1080 		if (error == 0)
1081 			error = nlookup(&nd);
1082 		if (error == 0)
1083 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
1084 		nlookup_done(&nd);
1085 	} else if (path == NULL) {
1086 		/* root mount */
1087 		cdev_t cdev = kgetdiskbyname(dev);
1088 		error = bdevvp(cdev, &devvp);
1089 		if (error)
1090 			kprintf("hammer2_mount: cannot find '%s'\n", dev);
1091 	} else {
1092 		/*
1093 		 * We will locate the hmp using the label in the hmp loop.
1094 		 */
1095 		error = 0;
1096 	}
1097 
1098 	/*
1099 	 * Make sure its a block device.  Do not check to see if it is
1100 	 * already mounted until we determine that its a fresh H2 device.
1101 	 */
1102 	if (error == 0 && devvp) {
1103 		if (!vn_isdisk(devvp, &error)) {
1104 			KKASSERT(error);
1105 			kprintf("hammer2_mount: %s not a block device %d\n",
1106 				dev, error);
1107 			vrele(devvp);
1108 			devvp = NULL;
1109 			return error;
1110 		}
1111 	}
1112 
1113 	/*
1114 	 * Determine if the device has already been mounted.  After this
1115 	 * check hmp will be non-NULL if we are doing the second or more
1116 	 * hammer2 mounts from the same device.
1117 	 */
1118 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1119 	if (devvp) {
1120 		/*
1121 		 * Match the device.  Due to the way devfs works,
1122 		 * we may not be able to directly match the vnode pointer,
1123 		 * so also check to see if the underlying device matches.
1124 		 */
1125 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1126 			if (hmp->devvp == devvp)
1127 				break;
1128 			if (devvp->v_rdev &&
1129 			    hmp->devvp->v_rdev == devvp->v_rdev) {
1130 				break;
1131 			}
1132 		}
1133 
1134 		/*
1135 		 * If no match this may be a fresh H2 mount, make sure
1136 		 * the device is not mounted on anything else.
1137 		 */
1138 		if (hmp == NULL)
1139 			error = vfs_mountedon(devvp);
1140 	} else if (error == 0) {
1141 		/*
1142 		 * Match the label to a pmp already probed.
1143 		 */
1144 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
1145 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
1146 				if (pmp->pfs_names[i] &&
1147 				    strcmp(pmp->pfs_names[i], label) == 0) {
1148 					hmp = pmp->pfs_hmps[i];
1149 					break;
1150 				}
1151 			}
1152 			if (hmp)
1153 				break;
1154 		}
1155 		if (hmp == NULL) {
1156 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1157 			kprintf("hammer2_mount: PFS label \"%s\" not found\n",
1158 				label);
1159 			return ENOENT;
1160 		}
1161 	}
1162 
1163 	/*
1164 	 * Open the device if this isn't a secondary mount and construct
1165 	 * the H2 device mount (hmp).
1166 	 */
1167 	if (hmp == NULL) {
1168 		hammer2_chain_t *schain;
1169 		hammer2_xid_t xid;
1170 		hammer2_xop_head_t xop;
1171 
1172 		if (error == 0 && vcount(devvp) > 0) {
1173 			kprintf("hammer2_mount: Primary device already has references\n");
1174 			error = EBUSY;
1175 		}
1176 
1177 		/*
1178 		 * Now open the device
1179 		 */
1180 		if (error == 0) {
1181 			ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
1182 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1183 			error = vinvalbuf(devvp, V_SAVE, 0, 0);
1184 			if (error == 0) {
1185 				error = VOP_OPEN(devvp,
1186 					     (ronly ? FREAD : FREAD | FWRITE),
1187 					     FSCRED, NULL);
1188 			}
1189 			vn_unlock(devvp);
1190 		}
1191 		if (error && devvp) {
1192 			vrele(devvp);
1193 			devvp = NULL;
1194 		}
1195 		if (error) {
1196 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1197 			return error;
1198 		}
1199 		hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
1200 		ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
1201 		hmp->ronly = ronly;
1202 		hmp->devvp = devvp;
1203 		hmp->hflags = info.hflags & HMNT2_DEVFLAGS;
1204 		kmalloc_create(&hmp->mchain, "HAMMER2-chains");
1205 		TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
1206 		RB_INIT(&hmp->iotree);
1207 		spin_init(&hmp->io_spin, "h2mount_io");
1208 		spin_init(&hmp->list_spin, "h2mount_list");
1209 
1210 		lockinit(&hmp->vollk, "h2vol", 0, 0);
1211 		lockinit(&hmp->bulklk, "h2bulk", 0, 0);
1212 		lockinit(&hmp->bflock, "h2bflk", 0, 0);
1213 
1214 		/*
1215 		 * vchain setup. vchain.data is embedded.
1216 		 * vchain.refs is initialized and will never drop to 0.
1217 		 *
1218 		 * NOTE! voldata is not yet loaded.
1219 		 */
1220 		hmp->vchain.hmp = hmp;
1221 		hmp->vchain.refs = 1;
1222 		hmp->vchain.data = (void *)&hmp->voldata;
1223 		hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
1224 		hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1225 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1226 		hammer2_chain_core_init(&hmp->vchain);
1227 
1228 		/*
1229 		 * fchain setup.  fchain.data is embedded.
1230 		 * fchain.refs is initialized and will never drop to 0.
1231 		 *
1232 		 * The data is not used but needs to be initialized to
1233 		 * pass assertion muster.  We use this chain primarily
1234 		 * as a placeholder for the freemap's top-level radix tree
1235 		 * so it does not interfere with the volume's topology
1236 		 * radix tree.
1237 		 */
1238 		hmp->fchain.hmp = hmp;
1239 		hmp->fchain.refs = 1;
1240 		hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
1241 		hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
1242 		hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1243 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1244 		hmp->fchain.bref.methods =
1245 			HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
1246 			HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
1247 		hammer2_chain_core_init(&hmp->fchain);
1248 
1249 		/*
1250 		 * Install the volume header and initialize fields from
1251 		 * voldata.
1252 		 */
1253 		error = hammer2_install_volume_header(hmp);
1254 		if (error) {
1255 			hammer2_unmount_helper(mp, NULL, hmp);
1256 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1257 			hammer2_vfs_unmount(mp, MNT_FORCE);
1258 			return error;
1259 		}
1260 
1261 		/*
1262 		 * Really important to get these right or the flush and
1263 		 * teardown code will get confused.
1264 		 */
1265 		hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0, NULL);
1266 		spmp = hmp->spmp;
1267 		spmp->pfs_hmps[0] = hmp;
1268 
1269 		/*
1270 		 * Dummy-up vchain and fchain's modify_tid.  mirror_tid
1271 		 * is inherited from the volume header.
1272 		 */
1273 		xid = 0;
1274 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1275 		hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
1276 		hmp->vchain.pmp = spmp;
1277 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1278 		hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
1279 		hmp->fchain.pmp = spmp;
1280 
1281 		/*
1282 		 * First locate the super-root inode, which is key 0
1283 		 * relative to the volume header's blockset.
1284 		 *
1285 		 * Then locate the root inode by scanning the directory keyspace
1286 		 * represented by the label.
1287 		 */
1288 		parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1289 		schain = hammer2_chain_lookup(&parent, &key_dummy,
1290 				      HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
1291 				      &error, 0);
1292 		hammer2_chain_lookup_done(parent);
1293 		if (schain == NULL) {
1294 			kprintf("hammer2_mount: invalid super-root\n");
1295 			hammer2_unmount_helper(mp, NULL, hmp);
1296 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1297 			hammer2_vfs_unmount(mp, MNT_FORCE);
1298 			return EINVAL;
1299 		}
1300 		if (schain->error) {
1301 			kprintf("hammer2_mount: error %s reading super-root\n",
1302 				hammer2_error_str(schain->error));
1303 			hammer2_chain_unlock(schain);
1304 			hammer2_chain_drop(schain);
1305 			schain = NULL;
1306 			hammer2_unmount_helper(mp, NULL, hmp);
1307 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1308 			hammer2_vfs_unmount(mp, MNT_FORCE);
1309 			return EINVAL;
1310 		}
1311 
1312 		/*
1313 		 * The super-root always uses an inode_tid of 1 when
1314 		 * creating PFSs.
1315 		 */
1316 		spmp->inode_tid = 1;
1317 		spmp->modify_tid = schain->bref.modify_tid + 1;
1318 
1319 		/*
1320 		 * Sanity-check schain's pmp and finish initialization.
1321 		 * Any chain belonging to the super-root topology should
1322 		 * have a NULL pmp (not even set to spmp).
1323 		 */
1324 		ripdata = &schain->data->ipdata;
1325 		KKASSERT(schain->pmp == NULL);
1326 		spmp->pfs_clid = ripdata->meta.pfs_clid;
1327 
1328 		/*
1329 		 * Replace the dummy spmp->iroot with a real one.  It's
1330 		 * easier to just do a wholesale replacement than to try
1331 		 * to update the chain and fixup the iroot fields.
1332 		 *
1333 		 * The returned inode is locked with the supplied cluster.
1334 		 */
1335 		hammer2_dummy_xop_from_chain(&xop, schain);
1336 		hammer2_inode_drop(spmp->iroot);
1337 		spmp->iroot = NULL;
1338 		spmp->iroot = hammer2_inode_get(spmp, &xop, -1, -1);
1339 		spmp->spmp_hmp = hmp;
1340 		spmp->pfs_types[0] = ripdata->meta.pfs_type;
1341 		spmp->pfs_hmps[0] = hmp;
1342 		hammer2_inode_ref(spmp->iroot);
1343 		hammer2_inode_unlock(spmp->iroot);
1344 		hammer2_cluster_unlock(&xop.cluster);
1345 		hammer2_chain_drop(schain);
1346 		/* do not call hammer2_cluster_drop() on an embedded cluster */
1347 		schain = NULL;	/* now invalid */
1348 		/* leave spmp->iroot with one ref */
1349 
1350 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1351 			error = hammer2_recovery(hmp);
1352 			if (error == 0)
1353 				error |= hammer2_fixup_pfses(hmp);
1354 			/* XXX do something with error */
1355 		}
1356 		hammer2_update_pmps(hmp);
1357 		hammer2_iocom_init(hmp);
1358 		hammer2_bulkfree_init(hmp);
1359 
1360 		/*
1361 		 * Ref the cluster management messaging descriptor.  The mount
1362 		 * program deals with the other end of the communications pipe.
1363 		 *
1364 		 * Root mounts typically do not supply one.
1365 		 */
1366 		if (info.cluster_fd >= 0) {
1367 			fp = holdfp(curthread, info.cluster_fd, -1);
1368 			if (fp) {
1369 				hammer2_cluster_reconnect(hmp, fp);
1370 			} else {
1371 				kprintf("hammer2_mount: bad cluster_fd!\n");
1372 			}
1373 		}
1374 	} else {
1375 		spmp = hmp->spmp;
1376 		if (info.hflags & HMNT2_DEVFLAGS) {
1377 			kprintf("hammer2_mount: Warning: mount flags pertaining "
1378 				"to the whole device may only be specified "
1379 				"on the first mount of the device: %08x\n",
1380 				info.hflags & HMNT2_DEVFLAGS);
1381 		}
1382 	}
1383 
1384 	/*
1385 	 * Force local mount (disassociate all PFSs from their clusters).
1386 	 * Used primarily for debugging.
1387 	 */
1388 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1389 
1390 	/*
1391 	 * Lookup the mount point under the media-localized super-root.
1392 	 * Scanning hammer2_pfslist doesn't help us because it represents
1393 	 * PFS cluster ids which can aggregate several named PFSs together.
1394 	 *
1395 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1396 	 * up later on.
1397 	 */
1398 	hammer2_inode_lock(spmp->iroot, 0);
1399 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1400 	lhc = hammer2_dirhash(label, strlen(label));
1401 	chain = hammer2_chain_lookup(&parent, &key_next,
1402 				     lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1403 				     &error, 0);
1404 	while (chain) {
1405 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1406 		    strcmp(label, chain->data->ipdata.filename) == 0) {
1407 			break;
1408 		}
1409 		chain = hammer2_chain_next(&parent, chain, &key_next,
1410 					    key_next,
1411 					    lhc + HAMMER2_DIRHASH_LOMASK,
1412 					    &error, 0);
1413 	}
1414 	if (parent) {
1415 		hammer2_chain_unlock(parent);
1416 		hammer2_chain_drop(parent);
1417 	}
1418 	hammer2_inode_unlock(spmp->iroot);
1419 
1420 	/*
1421 	 * PFS could not be found?
1422 	 */
1423 	if (chain == NULL) {
1424 		hammer2_unmount_helper(mp, NULL, hmp);
1425 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1426 		hammer2_vfs_unmount(mp, MNT_FORCE);
1427 
1428 		if (error) {
1429 			kprintf("hammer2_mount: PFS label I/O error\n");
1430 			return EINVAL;
1431 		} else {
1432 			kprintf("hammer2_mount: PFS label \"%s\" not found\n",
1433 				label);
1434 			return ENOENT;
1435 		}
1436 	}
1437 
1438 	/*
1439 	 * Acquire the pmp structure (it should have already been allocated
1440 	 * via hammer2_update_pmps() so do not pass cluster in to add to
1441 	 * available chains).
1442 	 *
1443 	 * Check if the cluster has already been mounted.  A cluster can
1444 	 * only be mounted once, use null mounts to mount additional copies.
1445 	 */
1446 	if (chain->error) {
1447 		kprintf("hammer2_mount: PFS label I/O error\n");
1448 	} else {
1449 		ripdata = &chain->data->ipdata;
1450 		bref = chain->bref;
1451 		pmp = hammer2_pfsalloc(NULL, ripdata,
1452 				       bref.modify_tid, force_local);
1453 	}
1454 	hammer2_chain_unlock(chain);
1455 	hammer2_chain_drop(chain);
1456 
1457 	/*
1458 	 * Finish the mount
1459 	 */
1460         kprintf("hammer2_mount: hmp=%p pmp=%p\n", hmp, pmp);
1461 
1462 	if (pmp->mp) {
1463 		kprintf("hammer2_mount: PFS already mounted!\n");
1464 		hammer2_unmount_helper(mp, NULL, hmp);
1465 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1466 		hammer2_vfs_unmount(mp, MNT_FORCE);
1467 
1468 		return EBUSY;
1469 	}
1470 
1471 	pmp->hflags = info.hflags;
1472         mp->mnt_flag |= MNT_LOCAL;
1473         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1474         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1475 
1476         /*
1477          * required mount structure initializations
1478          */
1479         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1480         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1481 
1482         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1483         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1484 
1485         /*
1486          * Optional fields
1487          */
1488         mp->mnt_iosize_max = MAXPHYS;
1489 
1490 	/*
1491 	 * Connect up mount pointers.
1492 	 */
1493 	hammer2_mount_helper(mp, pmp);
1494 	hmp->devvp->v_rdev->si_mountpoint = mp;
1495 
1496         lockmgr(&hammer2_mntlk, LK_RELEASE);
1497 
1498 	/*
1499 	 * Finish setup
1500 	 */
1501 	vfs_getnewfsid(mp);
1502 	vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1503 	vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1504 	vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1505 
1506 	if (path) {
1507 		copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1508 			  MNAMELEN - 1, &size);
1509 		bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1510 	} /* else root mount, already in there */
1511 
1512 	bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1513 	if (path) {
1514 		copyinstr(path, mp->mnt_stat.f_mntonname,
1515 			  sizeof(mp->mnt_stat.f_mntonname) - 1,
1516 			  &size);
1517 	} else {
1518 		/* root mount */
1519 		mp->mnt_stat.f_mntonname[0] = '/';
1520 	}
1521 
1522 	/*
1523 	 * Initial statfs to prime mnt_stat.
1524 	 */
1525 	hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1526 
1527 	return 0;
1528 }
1529 
1530 /*
1531  * Scan PFSs under the super-root and create hammer2_pfs structures.
1532  */
1533 static
1534 void
1535 hammer2_update_pmps(hammer2_dev_t *hmp)
1536 {
1537 	const hammer2_inode_data_t *ripdata;
1538 	hammer2_chain_t *parent;
1539 	hammer2_chain_t *chain;
1540 	hammer2_blockref_t bref;
1541 	hammer2_dev_t *force_local;
1542 	hammer2_pfs_t *spmp;
1543 	hammer2_pfs_t *pmp;
1544 	hammer2_key_t key_next;
1545 	int error;
1546 
1547 	/*
1548 	 * Force local mount (disassociate all PFSs from their clusters).
1549 	 * Used primarily for debugging.
1550 	 */
1551 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1552 
1553 	/*
1554 	 * Lookup mount point under the media-localized super-root.
1555 	 *
1556 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1557 	 * up later on.
1558 	 */
1559 	spmp = hmp->spmp;
1560 	hammer2_inode_lock(spmp->iroot, 0);
1561 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1562 	chain = hammer2_chain_lookup(&parent, &key_next,
1563 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1564 					 &error, 0);
1565 	while (chain) {
1566 		if (chain->error) {
1567 			kprintf("I/O error scanning PFS labels\n");
1568 		} else if (chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
1569 			kprintf("Non inode chain type %d under super-root\n",
1570 				chain->bref.type);
1571 		} else {
1572 			ripdata = &chain->data->ipdata;
1573 			bref = chain->bref;
1574 			pmp = hammer2_pfsalloc(chain, ripdata,
1575 					       bref.modify_tid, force_local);
1576 		}
1577 		chain = hammer2_chain_next(&parent, chain, &key_next,
1578 					   key_next, HAMMER2_KEY_MAX,
1579 					   &error, 0);
1580 	}
1581 	if (parent) {
1582 		hammer2_chain_unlock(parent);
1583 		hammer2_chain_drop(parent);
1584 	}
1585 	hammer2_inode_unlock(spmp->iroot);
1586 }
1587 
1588 static
1589 int
1590 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1591 		struct vnode *devvp, struct ucred *cred)
1592 {
1593 	int error;
1594 
1595 	if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
1596 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1597 		VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, NULL);
1598 		vn_unlock(devvp);
1599 		error = hammer2_recovery(hmp);
1600 		if (error == 0)
1601 			error |= hammer2_fixup_pfses(hmp);
1602 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1603 		if (error == 0) {
1604 			VOP_CLOSE(devvp, FREAD, NULL);
1605 			hmp->ronly = 0;
1606 		} else {
1607 			VOP_CLOSE(devvp, FREAD | FWRITE, NULL);
1608 		}
1609 		vn_unlock(devvp);
1610 	} else {
1611 		error = 0;
1612 	}
1613 	return error;
1614 }
1615 
1616 static
1617 int
1618 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1619 {
1620 	hammer2_pfs_t *pmp;
1621 	int flags;
1622 	int error = 0;
1623 
1624 	pmp = MPTOPMP(mp);
1625 
1626 	if (pmp == NULL)
1627 		return(0);
1628 
1629 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1630 
1631 	/*
1632 	 * If mount initialization proceeded far enough we must flush
1633 	 * its vnodes and sync the underlying mount points.  Three syncs
1634 	 * are required to fully flush the filesystem (freemap updates lag
1635 	 * by one flush, and one extra for safety).
1636 	 */
1637 	if (mntflags & MNT_FORCE)
1638 		flags = FORCECLOSE;
1639 	else
1640 		flags = 0;
1641 	if (pmp->iroot) {
1642 		error = vflush(mp, 0, flags);
1643 		if (error)
1644 			goto failed;
1645 		hammer2_vfs_sync(mp, MNT_WAIT);
1646 		hammer2_vfs_sync(mp, MNT_WAIT);
1647 		hammer2_vfs_sync(mp, MNT_WAIT);
1648 	}
1649 
1650 	/*
1651 	 * Cleanup the frontend support XOPS threads
1652 	 */
1653 	hammer2_xop_helper_cleanup(pmp);
1654 
1655 	if (pmp->mp)
1656 		hammer2_unmount_helper(mp, pmp, NULL);
1657 
1658 	error = 0;
1659 failed:
1660 	lockmgr(&hammer2_mntlk, LK_RELEASE);
1661 
1662 	return (error);
1663 }
1664 
1665 /*
1666  * Mount helper, hook the system mount into our PFS.
1667  * The mount lock is held.
1668  *
1669  * We must bump the mount_count on related devices for any
1670  * mounted PFSs.
1671  */
1672 static
1673 void
1674 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1675 {
1676 	hammer2_cluster_t *cluster;
1677 	hammer2_chain_t *rchain;
1678 	int i;
1679 
1680         mp->mnt_data = (qaddr_t)pmp;
1681 	pmp->mp = mp;
1682 
1683 	/*
1684 	 * After pmp->mp is set we have to adjust hmp->mount_count.
1685 	 */
1686 	cluster = &pmp->iroot->cluster;
1687 	for (i = 0; i < cluster->nchains; ++i) {
1688 		rchain = cluster->array[i].chain;
1689 		if (rchain == NULL)
1690 			continue;
1691 		++rchain->hmp->mount_count;
1692 	}
1693 
1694 	/*
1695 	 * Create missing Xop threads
1696 	 */
1697 	hammer2_xop_helper_create(pmp);
1698 }
1699 
1700 /*
1701  * Mount helper, unhook the system mount from our PFS.
1702  * The mount lock is held.
1703  *
1704  * If hmp is supplied a mount responsible for being the first to open
1705  * the block device failed and the block device and all PFSs using the
1706  * block device must be cleaned up.
1707  *
1708  * If pmp is supplied multiple devices might be backing the PFS and each
1709  * must be disconnected.  This might not be the last PFS using some of the
1710  * underlying devices.  Also, we have to adjust our hmp->mount_count
1711  * accounting for the devices backing the pmp which is now undergoing an
1712  * unmount.
1713  */
1714 static
1715 void
1716 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1717 {
1718 	hammer2_cluster_t *cluster;
1719 	hammer2_chain_t *rchain;
1720 	struct vnode *devvp;
1721 	int dumpcnt;
1722 	int ronly;
1723 	int i;
1724 
1725 	/*
1726 	 * If no device supplied this is a high-level unmount and we have to
1727 	 * to disconnect the mount, adjust mount_count, and locate devices
1728 	 * that might now have no mounts.
1729 	 */
1730 	if (pmp) {
1731 		KKASSERT(hmp == NULL);
1732 		KKASSERT((void *)(intptr_t)mp->mnt_data == pmp);
1733 		pmp->mp = NULL;
1734 		mp->mnt_data = NULL;
1735 
1736 		/*
1737 		 * After pmp->mp is cleared we have to account for
1738 		 * mount_count.
1739 		 */
1740 		cluster = &pmp->iroot->cluster;
1741 		for (i = 0; i < cluster->nchains; ++i) {
1742 			rchain = cluster->array[i].chain;
1743 			if (rchain == NULL)
1744 				continue;
1745 			--rchain->hmp->mount_count;
1746 			/* scrapping hmp now may invalidate the pmp */
1747 		}
1748 again:
1749 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1750 			if (hmp->mount_count == 0) {
1751 				hammer2_unmount_helper(NULL, NULL, hmp);
1752 				goto again;
1753 			}
1754 		}
1755 		return;
1756 	}
1757 
1758 	/*
1759 	 * Try to terminate the block device.  We can't terminate it if
1760 	 * there are still PFSs referencing it.
1761 	 */
1762 	if (hmp->mount_count)
1763 		return;
1764 
1765 	/*
1766 	 * Decomission the network before we start messing with the
1767 	 * device and PFS.
1768 	 */
1769 	hammer2_iocom_uninit(hmp);
1770 
1771 	hammer2_bulkfree_uninit(hmp);
1772 	hammer2_pfsfree_scan(hmp, 0);
1773 
1774 	/*
1775 	 * Cycle the volume data lock as a safety (probably not needed any
1776 	 * more).  To ensure everything is out we need to flush at least
1777 	 * three times.  (1) The running of the sideq can dirty the
1778 	 * filesystem, (2) A normal flush can dirty the freemap, and
1779 	 * (3) ensure that the freemap is fully synchronized.
1780 	 *
1781 	 * The next mount's recovery scan can clean everything up but we want
1782 	 * to leave the filesystem in a 100% clean state on a normal unmount.
1783 	 */
1784 #if 0
1785 	hammer2_voldata_lock(hmp);
1786 	hammer2_voldata_unlock(hmp);
1787 #endif
1788 
1789 	/*
1790 	 * Flush whatever is left.  Unmounted but modified PFS's might still
1791 	 * have some dirty chains on them.
1792 	 */
1793 	hammer2_chain_lock(&hmp->vchain, HAMMER2_RESOLVE_ALWAYS);
1794 	hammer2_chain_lock(&hmp->fchain, HAMMER2_RESOLVE_ALWAYS);
1795 
1796 	if (hmp->fchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1797 		hammer2_voldata_modify(hmp);
1798 		hammer2_flush(&hmp->fchain, HAMMER2_FLUSH_TOP |
1799 					    HAMMER2_FLUSH_ALL);
1800 	}
1801 	hammer2_chain_unlock(&hmp->fchain);
1802 
1803 	if (hmp->vchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1804 		hammer2_flush(&hmp->vchain, HAMMER2_FLUSH_TOP |
1805 					    HAMMER2_FLUSH_ALL);
1806 	}
1807 	hammer2_chain_unlock(&hmp->vchain);
1808 
1809 	if ((hmp->vchain.flags | hmp->fchain.flags) &
1810 	    HAMMER2_CHAIN_FLUSH_MASK) {
1811 		kprintf("hammer2_unmount: chains left over after final sync\n");
1812 		kprintf("    vchain %08x\n", hmp->vchain.flags);
1813 		kprintf("    fchain %08x\n", hmp->fchain.flags);
1814 
1815 		if (hammer2_debug & 0x0010)
1816 			Debugger("entered debugger");
1817 	}
1818 
1819 	hammer2_pfsfree_scan(hmp, 1);
1820 
1821 	KKASSERT(hmp->spmp == NULL);
1822 
1823 	/*
1824 	 * Finish up with the device vnode
1825 	 */
1826 	if ((devvp = hmp->devvp) != NULL) {
1827 		ronly = hmp->ronly;
1828 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1829 		kprintf("hammer2_unmount(A): devvp %s rbdirty %p ronly=%d\n",
1830 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree),
1831 			ronly);
1832 		vinvalbuf(devvp, (ronly ? 0 : V_SAVE), 0, 0);
1833 		kprintf("hammer2_unmount(B): devvp %s rbdirty %p\n",
1834 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree));
1835 		devvp->v_rdev->si_mountpoint = NULL;
1836 		hmp->devvp = NULL;
1837 		VOP_CLOSE(devvp, (ronly ? FREAD : FREAD|FWRITE), NULL);
1838 		vn_unlock(devvp);
1839 		vrele(devvp);
1840 		devvp = NULL;
1841 	}
1842 
1843 	/*
1844 	 * Clear vchain/fchain flags that might prevent final cleanup
1845 	 * of these chains.
1846 	 */
1847 	if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1848 		atomic_add_long(&hammer2_count_modified_chains, -1);
1849 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1850 		hammer2_pfs_memory_wakeup(hmp->vchain.pmp, -1);
1851 	}
1852 	if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1853 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_UPDATE);
1854 	}
1855 
1856 	if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1857 		atomic_add_long(&hammer2_count_modified_chains, -1);
1858 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_MODIFIED);
1859 		hammer2_pfs_memory_wakeup(hmp->fchain.pmp, -1);
1860 	}
1861 	if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1862 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_UPDATE);
1863 	}
1864 
1865 	/*
1866 	 * Final drop of embedded freemap root chain to
1867 	 * clean up fchain.core (fchain structure is not
1868 	 * flagged ALLOCATED so it is cleaned out and then
1869 	 * left to rot).
1870 	 */
1871 	hammer2_chain_drop(&hmp->fchain);
1872 
1873 	/*
1874 	 * Final drop of embedded volume root chain to clean
1875 	 * up vchain.core (vchain structure is not flagged
1876 	 * ALLOCATED so it is cleaned out and then left to
1877 	 * rot).
1878 	 */
1879 	dumpcnt = 50;
1880 	hammer2_dump_chain(&hmp->vchain, 0, 0, &dumpcnt, 'v', (u_int)-1);
1881 	dumpcnt = 50;
1882 	hammer2_dump_chain(&hmp->fchain, 0, 0, &dumpcnt, 'f', (u_int)-1);
1883 
1884 	hammer2_chain_drop(&hmp->vchain);
1885 
1886 	hammer2_io_cleanup(hmp, &hmp->iotree);
1887 	if (hmp->iofree_count) {
1888 		kprintf("io_cleanup: %d I/O's left hanging\n",
1889 			hmp->iofree_count);
1890 	}
1891 
1892 	TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1893 	kmalloc_destroy(&hmp->mchain);
1894 	kfree(hmp, M_HAMMER2);
1895 }
1896 
1897 int
1898 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1899 		 ino_t ino, struct vnode **vpp)
1900 {
1901 	hammer2_xop_lookup_t *xop;
1902 	hammer2_pfs_t *pmp;
1903 	hammer2_inode_t *ip;
1904 	hammer2_tid_t inum;
1905 	int error;
1906 
1907 	inum = (hammer2_tid_t)ino & HAMMER2_DIRHASH_USERMSK;
1908 
1909 	error = 0;
1910 	pmp = MPTOPMP(mp);
1911 
1912 	/*
1913 	 * Easy if we already have it cached
1914 	 */
1915 	ip = hammer2_inode_lookup(pmp, inum);
1916 	if (ip) {
1917 		hammer2_inode_lock(ip, HAMMER2_RESOLVE_SHARED);
1918 		*vpp = hammer2_igetv(ip, &error);
1919 		hammer2_inode_unlock(ip);
1920 		hammer2_inode_drop(ip);		/* from lookup */
1921 
1922 		return error;
1923 	}
1924 
1925 	/*
1926 	 * Otherwise we have to find the inode
1927 	 */
1928 	xop = hammer2_xop_alloc(pmp->iroot, 0);
1929 	xop->lhc = inum;
1930 	hammer2_xop_start(&xop->head, &hammer2_lookup_desc);
1931 	error = hammer2_xop_collect(&xop->head, 0);
1932 
1933 	if (error == 0)
1934 		ip = hammer2_inode_get(pmp, &xop->head, -1, -1);
1935 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1936 
1937 	if (ip) {
1938 		*vpp = hammer2_igetv(ip, &error);
1939 		hammer2_inode_unlock(ip);
1940 	} else {
1941 		*vpp = NULL;
1942 		error = ENOENT;
1943 	}
1944 	return (error);
1945 }
1946 
1947 static
1948 int
1949 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1950 {
1951 	hammer2_pfs_t *pmp;
1952 	struct vnode *vp;
1953 	int error;
1954 
1955 	pmp = MPTOPMP(mp);
1956 	if (pmp->iroot == NULL) {
1957 		kprintf("hammer2 (%s): no root inode\n",
1958 			mp->mnt_stat.f_mntfromname);
1959 		*vpp = NULL;
1960 		return EINVAL;
1961 	}
1962 
1963 	error = 0;
1964 	hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1965 
1966 	while (pmp->inode_tid == 0) {
1967 		hammer2_xop_ipcluster_t *xop;
1968 		const hammer2_inode_meta_t *meta;
1969 
1970 		xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1971 		hammer2_xop_start(&xop->head, &hammer2_ipcluster_desc);
1972 		error = hammer2_xop_collect(&xop->head, 0);
1973 
1974 		if (error == 0) {
1975 			meta = &hammer2_xop_gdata(&xop->head)->ipdata.meta;
1976 			pmp->iroot->meta = *meta;
1977 			pmp->inode_tid = meta->pfs_inum + 1;
1978 			hammer2_xop_pdata(&xop->head);
1979 			/* meta invalid */
1980 
1981 			if (pmp->inode_tid < HAMMER2_INODE_START)
1982 				pmp->inode_tid = HAMMER2_INODE_START;
1983 			pmp->modify_tid =
1984 				xop->head.cluster.focus->bref.modify_tid + 1;
1985 #if 0
1986 			kprintf("PFS: Starting inode %jd\n",
1987 				(intmax_t)pmp->inode_tid);
1988 			kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1989 				pmp->inode_tid, pmp->modify_tid);
1990 #endif
1991 			wakeup(&pmp->iroot);
1992 
1993 			hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1994 
1995 			/*
1996 			 * Prime the mount info.
1997 			 */
1998 			hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
1999 			break;
2000 		}
2001 
2002 		/*
2003 		 * Loop, try again
2004 		 */
2005 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2006 		hammer2_inode_unlock(pmp->iroot);
2007 		error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
2008 		hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
2009 		if (error == EINTR)
2010 			break;
2011 	}
2012 
2013 	if (error) {
2014 		hammer2_inode_unlock(pmp->iroot);
2015 		*vpp = NULL;
2016 	} else {
2017 		vp = hammer2_igetv(pmp->iroot, &error);
2018 		hammer2_inode_unlock(pmp->iroot);
2019 		*vpp = vp;
2020 	}
2021 
2022 	return (error);
2023 }
2024 
2025 /*
2026  * Filesystem status
2027  *
2028  * XXX incorporate ipdata->meta.inode_quota and data_quota
2029  */
2030 static
2031 int
2032 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
2033 {
2034 	hammer2_pfs_t *pmp;
2035 	hammer2_dev_t *hmp;
2036 	hammer2_blockref_t bref;
2037 	struct statfs tmp;
2038 	int i;
2039 
2040 	/*
2041 	 * NOTE: iroot might not have validated the cluster yet.
2042 	 */
2043 	pmp = MPTOPMP(mp);
2044 
2045 	bzero(&tmp, sizeof(tmp));
2046 
2047 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2048 		hmp = pmp->pfs_hmps[i];
2049 		if (hmp == NULL)
2050 			continue;
2051 		if (pmp->iroot->cluster.array[i].chain)
2052 			bref = pmp->iroot->cluster.array[i].chain->bref;
2053 		else
2054 			bzero(&bref, sizeof(bref));
2055 
2056 		tmp.f_files = bref.embed.stats.inode_count;
2057 		tmp.f_ffree = 0;
2058 		tmp.f_blocks = hmp->voldata.allocator_size /
2059 			       mp->mnt_vstat.f_bsize;
2060 		tmp.f_bfree = hmp->voldata.allocator_free /
2061 			      mp->mnt_vstat.f_bsize;
2062 		tmp.f_bavail = tmp.f_bfree;
2063 
2064 		if (cred && cred->cr_uid != 0) {
2065 			uint64_t adj;
2066 
2067 			/* 5% */
2068 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2069 			tmp.f_blocks -= adj;
2070 			tmp.f_bfree -= adj;
2071 			tmp.f_bavail -= adj;
2072 		}
2073 
2074 		mp->mnt_stat.f_blocks = tmp.f_blocks;
2075 		mp->mnt_stat.f_bfree = tmp.f_bfree;
2076 		mp->mnt_stat.f_bavail = tmp.f_bavail;
2077 		mp->mnt_stat.f_files = tmp.f_files;
2078 		mp->mnt_stat.f_ffree = tmp.f_ffree;
2079 
2080 		*sbp = mp->mnt_stat;
2081 	}
2082 	return (0);
2083 }
2084 
2085 static
2086 int
2087 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
2088 {
2089 	hammer2_pfs_t *pmp;
2090 	hammer2_dev_t *hmp;
2091 	hammer2_blockref_t bref;
2092 	struct statvfs tmp;
2093 	int i;
2094 
2095 	/*
2096 	 * NOTE: iroot might not have validated the cluster yet.
2097 	 */
2098 	pmp = MPTOPMP(mp);
2099 	bzero(&tmp, sizeof(tmp));
2100 
2101 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2102 		hmp = pmp->pfs_hmps[i];
2103 		if (hmp == NULL)
2104 			continue;
2105 		if (pmp->iroot->cluster.array[i].chain)
2106 			bref = pmp->iroot->cluster.array[i].chain->bref;
2107 		else
2108 			bzero(&bref, sizeof(bref));
2109 
2110 		tmp.f_files = bref.embed.stats.inode_count;
2111 		tmp.f_ffree = 0;
2112 		tmp.f_blocks = hmp->voldata.allocator_size /
2113 			       mp->mnt_vstat.f_bsize;
2114 		tmp.f_bfree = hmp->voldata.allocator_free /
2115 			      mp->mnt_vstat.f_bsize;
2116 		tmp.f_bavail = tmp.f_bfree;
2117 
2118 		if (cred && cred->cr_uid != 0) {
2119 			uint64_t adj;
2120 
2121 			/* 5% */
2122 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2123 			tmp.f_blocks -= adj;
2124 			tmp.f_bfree -= adj;
2125 			tmp.f_bavail -= adj;
2126 		}
2127 
2128 		mp->mnt_vstat.f_blocks = tmp.f_blocks;
2129 		mp->mnt_vstat.f_bfree = tmp.f_bfree;
2130 		mp->mnt_vstat.f_bavail = tmp.f_bavail;
2131 		mp->mnt_vstat.f_files = tmp.f_files;
2132 		mp->mnt_vstat.f_ffree = tmp.f_ffree;
2133 
2134 		*sbp = mp->mnt_vstat;
2135 	}
2136 	return (0);
2137 }
2138 
2139 /*
2140  * Mount-time recovery (RW mounts)
2141  *
2142  * Updates to the free block table are allowed to lag flushes by one
2143  * transaction.  In case of a crash, then on a fresh mount we must do an
2144  * incremental scan of the last committed transaction id and make sure that
2145  * all related blocks have been marked allocated.
2146  */
2147 struct hammer2_recovery_elm {
2148 	TAILQ_ENTRY(hammer2_recovery_elm) entry;
2149 	hammer2_chain_t *chain;
2150 	hammer2_tid_t sync_tid;
2151 };
2152 
2153 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
2154 
2155 struct hammer2_recovery_info {
2156 	struct hammer2_recovery_list list;
2157 	hammer2_tid_t	mtid;
2158 	int	depth;
2159 };
2160 
2161 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
2162 			hammer2_chain_t *parent,
2163 			struct hammer2_recovery_info *info,
2164 			hammer2_tid_t sync_tid);
2165 
2166 #define HAMMER2_RECOVERY_MAXDEPTH	10
2167 
2168 static
2169 int
2170 hammer2_recovery(hammer2_dev_t *hmp)
2171 {
2172 	struct hammer2_recovery_info info;
2173 	struct hammer2_recovery_elm *elm;
2174 	hammer2_chain_t *parent;
2175 	hammer2_tid_t sync_tid;
2176 	hammer2_tid_t mirror_tid;
2177 	int error;
2178 
2179 	hammer2_trans_init(hmp->spmp, 0);
2180 
2181 	sync_tid = hmp->voldata.freemap_tid;
2182 	mirror_tid = hmp->voldata.mirror_tid;
2183 
2184 	kprintf("hammer2_mount: \"%s\": ", hmp->devrepname);
2185 	if (sync_tid >= mirror_tid) {
2186 		kprintf("no recovery needed\n");
2187 	} else {
2188 		kprintf("freemap recovery %016jx-%016jx\n",
2189 			sync_tid + 1, mirror_tid);
2190 	}
2191 
2192 	TAILQ_INIT(&info.list);
2193 	info.depth = 0;
2194 	parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
2195 	error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
2196 	hammer2_chain_lookup_done(parent);
2197 
2198 	while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
2199 		TAILQ_REMOVE(&info.list, elm, entry);
2200 		parent = elm->chain;
2201 		sync_tid = elm->sync_tid;
2202 		kfree(elm, M_HAMMER2);
2203 
2204 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2205 		error |= hammer2_recovery_scan(hmp, parent, &info,
2206 					      hmp->voldata.freemap_tid);
2207 		hammer2_chain_unlock(parent);
2208 		hammer2_chain_drop(parent);	/* drop elm->chain ref */
2209 	}
2210 
2211 	hammer2_trans_done(hmp->spmp, 0);
2212 
2213 	return error;
2214 }
2215 
2216 static
2217 int
2218 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
2219 		      struct hammer2_recovery_info *info,
2220 		      hammer2_tid_t sync_tid)
2221 {
2222 	const hammer2_inode_data_t *ripdata;
2223 	hammer2_chain_t *chain;
2224 	hammer2_blockref_t bref;
2225 	int tmp_error;
2226 	int rup_error;
2227 	int error;
2228 	int first;
2229 
2230 	/*
2231 	 * Adjust freemap to ensure that the block(s) are marked allocated.
2232 	 */
2233 	if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
2234 		hammer2_freemap_adjust(hmp, &parent->bref,
2235 				       HAMMER2_FREEMAP_DORECOVER);
2236 	}
2237 
2238 	/*
2239 	 * Check type for recursive scan
2240 	 */
2241 	switch(parent->bref.type) {
2242 	case HAMMER2_BREF_TYPE_VOLUME:
2243 		/* data already instantiated */
2244 		break;
2245 	case HAMMER2_BREF_TYPE_INODE:
2246 		/*
2247 		 * Must instantiate data for DIRECTDATA test and also
2248 		 * for recursion.
2249 		 */
2250 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2251 		ripdata = &parent->data->ipdata;
2252 		if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
2253 			/* not applicable to recovery scan */
2254 			hammer2_chain_unlock(parent);
2255 			return 0;
2256 		}
2257 		hammer2_chain_unlock(parent);
2258 		break;
2259 	case HAMMER2_BREF_TYPE_INDIRECT:
2260 		/*
2261 		 * Must instantiate data for recursion
2262 		 */
2263 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2264 		hammer2_chain_unlock(parent);
2265 		break;
2266 	case HAMMER2_BREF_TYPE_DIRENT:
2267 	case HAMMER2_BREF_TYPE_DATA:
2268 	case HAMMER2_BREF_TYPE_FREEMAP:
2269 	case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2270 	case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2271 		/* not applicable to recovery scan */
2272 		return 0;
2273 		break;
2274 	default:
2275 		return HAMMER2_ERROR_BADBREF;
2276 	}
2277 
2278 	/*
2279 	 * Defer operation if depth limit reached.
2280 	 */
2281 	if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
2282 		struct hammer2_recovery_elm *elm;
2283 
2284 		elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
2285 		elm->chain = parent;
2286 		elm->sync_tid = sync_tid;
2287 		hammer2_chain_ref(parent);
2288 		TAILQ_INSERT_TAIL(&info->list, elm, entry);
2289 		/* unlocked by caller */
2290 
2291 		return(0);
2292 	}
2293 
2294 
2295 	/*
2296 	 * Recursive scan of the last flushed transaction only.  We are
2297 	 * doing this without pmp assignments so don't leave the chains
2298 	 * hanging around after we are done with them.
2299 	 *
2300 	 * error	Cumulative error this level only
2301 	 * rup_error	Cumulative error for recursion
2302 	 * tmp_error	Specific non-cumulative recursion error
2303 	 */
2304 	chain = NULL;
2305 	first = 1;
2306 	rup_error = 0;
2307 	error = 0;
2308 
2309 	for (;;) {
2310 		error |= hammer2_chain_scan(parent, &chain, &bref,
2311 					    &first,
2312 					    HAMMER2_LOOKUP_NODATA);
2313 
2314 		/*
2315 		 * Problem during scan or EOF
2316 		 */
2317 		if (error)
2318 			break;
2319 
2320 		/*
2321 		 * If this is a leaf
2322 		 */
2323 		if (chain == NULL) {
2324 			if (bref.mirror_tid > sync_tid) {
2325 				hammer2_freemap_adjust(hmp, &bref,
2326 						     HAMMER2_FREEMAP_DORECOVER);
2327 			}
2328 			continue;
2329 		}
2330 
2331 		/*
2332 		 * This may or may not be a recursive node.
2333 		 */
2334 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
2335 		if (bref.mirror_tid > sync_tid) {
2336 			++info->depth;
2337 			tmp_error = hammer2_recovery_scan(hmp, chain,
2338 							   info, sync_tid);
2339 			--info->depth;
2340 		} else {
2341 			tmp_error = 0;
2342 		}
2343 
2344 		/*
2345 		 * Flush the recovery at the PFS boundary to stage it for
2346 		 * the final flush of the super-root topology.
2347 		 */
2348 		if (tmp_error == 0 &&
2349 		    (bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
2350 		    (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
2351 			hammer2_flush(chain, HAMMER2_FLUSH_TOP |
2352 					     HAMMER2_FLUSH_ALL);
2353 		}
2354 		rup_error |= tmp_error;
2355 	}
2356 	return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
2357 }
2358 
2359 /*
2360  * This fixes up an error introduced in earlier H2 implementations where
2361  * moving a PFS inode into an indirect block wound up causing the
2362  * HAMMER2_BREF_FLAG_PFSROOT flag in the bref to get cleared.
2363  */
2364 static
2365 int
2366 hammer2_fixup_pfses(hammer2_dev_t *hmp)
2367 {
2368 	const hammer2_inode_data_t *ripdata;
2369 	hammer2_chain_t *parent;
2370 	hammer2_chain_t *chain;
2371 	hammer2_key_t key_next;
2372 	hammer2_pfs_t *spmp;
2373 	int error;
2374 
2375 	error = 0;
2376 
2377 	/*
2378 	 * Lookup mount point under the media-localized super-root.
2379 	 *
2380 	 * cluster->pmp will incorrectly point to spmp and must be fixed
2381 	 * up later on.
2382 	 */
2383 	spmp = hmp->spmp;
2384 	hammer2_inode_lock(spmp->iroot, 0);
2385 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
2386 	chain = hammer2_chain_lookup(&parent, &key_next,
2387 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
2388 					 &error, 0);
2389 	while (chain) {
2390 		if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
2391 			continue;
2392 		if (chain->error) {
2393 			kprintf("I/O error scanning PFS labels\n");
2394 			error |= chain->error;
2395 		} else if ((chain->bref.flags &
2396 			    HAMMER2_BREF_FLAG_PFSROOT) == 0) {
2397 			int error2;
2398 
2399 			ripdata = &chain->data->ipdata;
2400 			hammer2_trans_init(hmp->spmp, 0);
2401 			error2 = hammer2_chain_modify(chain,
2402 						      chain->bref.modify_tid,
2403 						      0, 0);
2404 			if (error2 == 0) {
2405 				kprintf("hammer2: Correct mis-flagged PFS %s\n",
2406 					ripdata->filename);
2407 				chain->bref.flags |= HAMMER2_BREF_FLAG_PFSROOT;
2408 			} else {
2409 				error |= error2;
2410 			}
2411 			hammer2_flush(chain, HAMMER2_FLUSH_TOP |
2412 					     HAMMER2_FLUSH_ALL);
2413 			hammer2_trans_done(hmp->spmp, 0);
2414 		}
2415 		chain = hammer2_chain_next(&parent, chain, &key_next,
2416 					   key_next, HAMMER2_KEY_MAX,
2417 					   &error, 0);
2418 	}
2419 	if (parent) {
2420 		hammer2_chain_unlock(parent);
2421 		hammer2_chain_drop(parent);
2422 	}
2423 	hammer2_inode_unlock(spmp->iroot);
2424 
2425 	return error;
2426 }
2427 
2428 /*
2429  * Sync a mount point; this is called periodically on a per-mount basis from
2430  * the filesystem syncer, and whenever a user issues a sync.
2431  */
2432 int
2433 hammer2_vfs_sync(struct mount *mp, int waitfor)
2434 {
2435 	int error;
2436 
2437 	error = hammer2_vfs_sync_pmp(MPTOPMP(mp), waitfor);
2438 
2439 	return error;
2440 }
2441 
2442 /*
2443  * Because frontend operations lock vnodes before we get a chance to
2444  * lock the related inode, we can't just acquire a vnode lock without
2445  * risking a deadlock.  The frontend may be holding a vnode lock while
2446  * also blocked on our SYNCQ flag while trying to get the inode lock.
2447  *
2448  * To deal with this situation we can check the vnode lock situation
2449  * after locking the inode and perform a work-around.
2450  */
2451 int
2452 hammer2_vfs_sync_pmp(hammer2_pfs_t *pmp, int waitfor)
2453 {
2454 	struct mount *mp;
2455 	/*hammer2_xop_flush_t *xop;*/
2456 	/*struct hammer2_sync_info info;*/
2457 	hammer2_inode_t *ip;
2458 	hammer2_depend_t *depend;
2459 	hammer2_depend_t *depend_next;
2460 	struct vnode *vp;
2461 	uint32_t pass2;
2462 	int error;
2463 	int wakecount;
2464 	int dorestart;
2465 
2466 	mp = pmp->mp;
2467 
2468 	/*
2469 	 * Move all inodes on sideq to syncq.  This will clear sideq.
2470 	 * This should represent all flushable inodes.  These inodes
2471 	 * will already have refs due to being on syncq or sideq.  We
2472 	 * must do this all at once with the spinlock held to ensure that
2473 	 * all inode dependencies are part of the same flush.
2474 	 *
2475 	 * We should be able to do this asynchronously from frontend
2476 	 * operations because we will be locking the inodes later on
2477 	 * to actually flush them, and that will partition any frontend
2478 	 * op using the same inode.  Either it has already locked the
2479 	 * inode and we will block, or it has not yet locked the inode
2480 	 * and it will block until we are finished flushing that inode.
2481 	 *
2482 	 * When restarting, only move the inodes flagged as PASS2 from
2483 	 * SIDEQ to SYNCQ.  PASS2 propagation by inode_lock4() and
2484 	 * inode_depend() are atomic with the spin-lock.
2485 	 */
2486 	hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
2487 #ifdef HAMMER2_DEBUG_SYNC
2488 	kprintf("FILESYSTEM SYNC BOUNDARY\n");
2489 #endif
2490 	dorestart = 0;
2491 
2492 	/*
2493 	 * Move inodes from depq to syncq, releasing the related
2494 	 * depend structures.
2495 	 */
2496 restart:
2497 #ifdef HAMMER2_DEBUG_SYNC
2498 	kprintf("FILESYSTEM SYNC RESTART (%d)\n", dorestart);
2499 #endif
2500 	hammer2_trans_setflags(pmp, 0/*HAMMER2_TRANS_COPYQ*/);
2501 	hammer2_trans_clearflags(pmp, HAMMER2_TRANS_RESCAN);
2502 
2503 	/*
2504 	 * Move inodes from depq to syncq.  When restarting, only depq's
2505 	 * marked pass2 are moved.
2506 	 */
2507 	hammer2_spin_ex(&pmp->list_spin);
2508 	depend_next = TAILQ_FIRST(&pmp->depq);
2509 	wakecount = 0;
2510 
2511 	while ((depend = depend_next) != NULL) {
2512 		depend_next = TAILQ_NEXT(depend, entry);
2513 		if (dorestart && depend->pass2 == 0)
2514 			continue;
2515 		TAILQ_FOREACH(ip, &depend->sideq, entry) {
2516 			KKASSERT(ip->flags & HAMMER2_INODE_SIDEQ);
2517 			atomic_set_int(&ip->flags, HAMMER2_INODE_SYNCQ);
2518 			atomic_clear_int(&ip->flags, HAMMER2_INODE_SIDEQ);
2519 			ip->depend = NULL;
2520 		}
2521 
2522 		/*
2523 		 * NOTE: pmp->sideq_count includes both sideq and syncq
2524 		 */
2525 		TAILQ_CONCAT(&pmp->syncq, &depend->sideq, entry);
2526 
2527 		depend->count = 0;
2528 		depend->pass2 = 0;
2529 		TAILQ_REMOVE(&pmp->depq, depend, entry);
2530 	}
2531 
2532 	hammer2_spin_unex(&pmp->list_spin);
2533 	hammer2_trans_clearflags(pmp, /*HAMMER2_TRANS_COPYQ |*/
2534 				      HAMMER2_TRANS_WAITING);
2535 	dorestart = 0;
2536 
2537 	/*
2538 	 * sideq_count may have dropped enough to allow us to unstall
2539 	 * the frontend.
2540 	 */
2541 	hammer2_pfs_memory_wakeup(pmp, 0);
2542 
2543 	/*
2544 	 * Now run through all inodes on syncq.
2545 	 *
2546 	 * Flush transactions only interlock with other flush transactions.
2547 	 * Any conflicting frontend operations will block on the inode, but
2548 	 * may hold a vnode lock while doing so.
2549 	 */
2550 	hammer2_spin_ex(&pmp->list_spin);
2551 	while ((ip = TAILQ_FIRST(&pmp->syncq)) != NULL) {
2552 		/*
2553 		 * Remove the inode from the SYNCQ, transfer the syncq ref
2554 		 * to us.  We must clear SYNCQ to allow any potential
2555 		 * front-end deadlock to proceed.  We must set PASS2 so
2556 		 * the dependency code knows what to do.
2557 		 */
2558 		pass2 = ip->flags;
2559 		cpu_ccfence();
2560 		if (atomic_cmpset_int(&ip->flags,
2561 			      pass2,
2562 			      (pass2 & ~(HAMMER2_INODE_SYNCQ |
2563 					 HAMMER2_INODE_SYNCQ_WAKEUP)) |
2564 			      HAMMER2_INODE_SYNCQ_PASS2) == 0) {
2565 			continue;
2566 		}
2567 		TAILQ_REMOVE(&pmp->syncq, ip, entry);
2568 		--pmp->sideq_count;
2569 		hammer2_spin_unex(&pmp->list_spin);
2570 
2571 		/*
2572 		 * Tickle anyone waiting on ip->flags or the hysteresis
2573 		 * on the dirty inode count.
2574 		 */
2575 		if (pass2 & HAMMER2_INODE_SYNCQ_WAKEUP)
2576 			wakeup(&ip->flags);
2577 		if (++wakecount >= hammer2_limit_dirty_inodes / 20 + 1) {
2578 			wakecount = 0;
2579 			hammer2_pfs_memory_wakeup(pmp, 0);
2580 		}
2581 
2582 		/*
2583 		 * Relock the inode, and we inherit a ref from the above.
2584 		 * We will check for a race after we acquire the vnode.
2585 		 */
2586 		hammer2_mtx_ex(&ip->lock);
2587 
2588 		/*
2589 		 * We need the vp in order to vfsync() dirty buffers, so if
2590 		 * one isn't attached we can skip it.
2591 		 *
2592 		 * Ordering the inode lock and then the vnode lock has the
2593 		 * potential to deadlock.  If we had left SYNCQ set that could
2594 		 * also deadlock us against the frontend even if we don't hold
2595 		 * any locks, but the latter is not a problem now since we
2596 		 * cleared it.  igetv will temporarily release the inode lock
2597 		 * in a safe manner to work-around the deadlock.
2598 		 *
2599 		 * Unfortunately it is still possible to deadlock when the
2600 		 * frontend obtains multiple inode locks, because all the
2601 		 * related vnodes are already locked (nor can the vnode locks
2602 		 * be released and reacquired without messing up RECLAIM and
2603 		 * INACTIVE sequencing).
2604 		 *
2605 		 * The solution for now is to move the vp back onto SIDEQ
2606 		 * and set dorestart, which will restart the flush after we
2607 		 * exhaust the current SYNCQ.  Note that additional
2608 		 * dependencies may build up, so we definitely need to move
2609 		 * the whole SIDEQ back to SYNCQ when we restart.
2610 		 */
2611 		vp = ip->vp;
2612 		if (vp) {
2613 			if (vget(vp, LK_EXCLUSIVE|LK_NOWAIT)) {
2614 				/*
2615 				 * Failed to get the vnode, requeue the inode
2616 				 * (PASS2 is already set so it will be found
2617 				 * again on the restart).
2618 				 *
2619 				 * Then unlock, possibly sleep, and retry
2620 				 * later.  We sleep if PASS2 was *previously*
2621 				 * set, before we set it again above.
2622 				 */
2623 				vp = NULL;
2624 				dorestart = 1;
2625 #ifdef HAMMER2_DEBUG_SYNC
2626 				kprintf("inum %ld (sync delayed by vnode)\n",
2627 					(long)ip->meta.inum);
2628 #endif
2629 				hammer2_inode_delayed_sideq(ip);
2630 
2631 				hammer2_mtx_unlock(&ip->lock);
2632 				hammer2_inode_drop(ip);
2633 
2634 				if (pass2 & HAMMER2_INODE_SYNCQ_PASS2) {
2635 					tsleep(&dorestart, 0, "h2syndel", 2);
2636 				}
2637 				hammer2_spin_ex(&pmp->list_spin);
2638 				continue;
2639 			}
2640 		} else {
2641 			vp = NULL;
2642 		}
2643 
2644 		/*
2645 		 * If the inode wound up on a SIDEQ again it will already be
2646 		 * prepped for another PASS2.  In this situation if we flush
2647 		 * it now we will just wind up flushing it again in the same
2648 		 * syncer run, so we might as well not flush it now.
2649 		 */
2650 		if (ip->flags & HAMMER2_INODE_SIDEQ) {
2651 			hammer2_mtx_unlock(&ip->lock);
2652 			hammer2_inode_drop(ip);
2653 			if (vp)
2654 				vput(vp);
2655 			dorestart = 1;
2656 			hammer2_spin_ex(&pmp->list_spin);
2657 			continue;
2658 		}
2659 
2660 		/*
2661 		 * Ok we have the inode exclusively locked and if vp is
2662 		 * not NULL that will also be exclusively locked.  Do the
2663 		 * meat of the flush.
2664 		 *
2665 		 * vp token needed for v_rbdirty_tree check / vclrisdirty
2666 		 * sequencing.  Though we hold the vnode exclusively so
2667 		 * we shouldn't need to hold the token also in this case.
2668 		 */
2669 		if (vp) {
2670 			vfsync(vp, MNT_WAIT, 1, NULL, NULL);
2671 			bio_track_wait(&vp->v_track_write, 0, 0); /* XXX */
2672 		}
2673 
2674 		/*
2675 		 * If the inode has not yet been inserted into the tree
2676 		 * we must do so.  Then sync and flush it.  The flush should
2677 		 * update the parent.
2678 		 */
2679 		if (ip->flags & HAMMER2_INODE_DELETING) {
2680 #ifdef HAMMER2_DEBUG_SYNC
2681 			kprintf("inum %ld destroy\n", (long)ip->meta.inum);
2682 #endif
2683 			hammer2_inode_chain_des(ip);
2684 			atomic_add_long(&hammer2_iod_inode_deletes, 1);
2685 		} else if (ip->flags & HAMMER2_INODE_CREATING) {
2686 #ifdef HAMMER2_DEBUG_SYNC
2687 			kprintf("inum %ld insert\n", (long)ip->meta.inum);
2688 #endif
2689 			hammer2_inode_chain_ins(ip);
2690 			atomic_add_long(&hammer2_iod_inode_creates, 1);
2691 		}
2692 #ifdef HAMMER2_DEBUG_SYNC
2693 		kprintf("inum %ld chain-sync\n", (long)ip->meta.inum);
2694 #endif
2695 
2696 		/*
2697 		 * Because I kinda messed up the design and index the inodes
2698 		 * under the root inode, along side the directory entries,
2699 		 * we can't flush the inode index under the iroot until the
2700 		 * end.  If we do it now we might miss effects created by
2701 		 * other inodes on the SYNCQ.
2702 		 *
2703 		 * Do a normal (non-FSSYNC) flush instead, which allows the
2704 		 * vnode code to work the same.  We don't want to force iroot
2705 		 * back onto the SIDEQ, and we also don't want the flush code
2706 		 * to update pfs_iroot_blocksets until the final flush later.
2707 		 *
2708 		 * XXX at the moment this will likely result in a double-flush
2709 		 * of the iroot chain.
2710 		 */
2711 		hammer2_inode_chain_sync(ip);
2712 		if (ip == pmp->iroot) {
2713 			hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP);
2714 		} else {
2715 			hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP |
2716 						      HAMMER2_XOP_FSSYNC);
2717 		}
2718 		if (vp) {
2719 			lwkt_gettoken(&vp->v_token);
2720 			if ((ip->flags & (HAMMER2_INODE_MODIFIED |
2721 					  HAMMER2_INODE_RESIZED |
2722 					  HAMMER2_INODE_DIRTYDATA)) == 0 &&
2723 			    RB_EMPTY(&vp->v_rbdirty_tree) &&
2724 			    !bio_track_active(&vp->v_track_write)) {
2725 				vclrisdirty(vp);
2726 			} else {
2727 				hammer2_inode_delayed_sideq(ip);
2728 			}
2729 			lwkt_reltoken(&vp->v_token);
2730 			vput(vp);
2731 			vp = NULL;	/* safety */
2732 		}
2733 		atomic_clear_int(&ip->flags, HAMMER2_INODE_SYNCQ_PASS2);
2734 		hammer2_inode_unlock(ip);	/* unlock+drop */
2735 		/* ip pointer invalid */
2736 
2737 		/*
2738 		 * If the inode got dirted after we dropped our locks,
2739 		 * it will have already been moved back to the SIDEQ.
2740 		 */
2741 		hammer2_spin_ex(&pmp->list_spin);
2742 	}
2743 	hammer2_spin_unex(&pmp->list_spin);
2744 	hammer2_pfs_memory_wakeup(pmp, 0);
2745 
2746 	if (dorestart || (pmp->trans.flags & HAMMER2_TRANS_RESCAN)) {
2747 #ifdef HAMMER2_DEBUG_SYNC
2748 		kprintf("FILESYSTEM SYNC STAGE 1 RESTART\n");
2749 		/*tsleep(&dorestart, 0, "h2STG1-R", hz*20);*/
2750 #endif
2751 		dorestart = 1;
2752 		goto restart;
2753 	}
2754 #ifdef HAMMER2_DEBUG_SYNC
2755 	kprintf("FILESYSTEM SYNC STAGE 2 BEGIN\n");
2756 	/*tsleep(&dorestart, 0, "h2STG2", hz*20);*/
2757 #endif
2758 
2759 	/*
2760 	 * We have to flush the PFS root last, even if it does not appear to
2761 	 * be dirty, because all the inodes in the PFS are indexed under it.
2762 	 * The normal flushing of iroot above would only occur if directory
2763 	 * entries under the root were changed.
2764 	 *
2765 	 * Specifying VOLHDR will cause an additionl flush of hmp->spmp
2766 	 * for the media making up the cluster.
2767 	 */
2768 	if ((ip = pmp->iroot) != NULL) {
2769 		hammer2_inode_ref(ip);
2770 		hammer2_mtx_ex(&ip->lock);
2771 		hammer2_inode_chain_sync(ip);
2772 		hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP |
2773 					      HAMMER2_XOP_FSSYNC |
2774 					      HAMMER2_XOP_VOLHDR);
2775 		hammer2_inode_unlock(ip);	/* unlock+drop */
2776 	}
2777 #ifdef HAMMER2_DEBUG_SYNC
2778 	kprintf("FILESYSTEM SYNC STAGE 2 DONE\n");
2779 #endif
2780 
2781 	/*
2782 	 * device bioq sync
2783 	 */
2784 	hammer2_bioq_sync(pmp);
2785 
2786 #if 0
2787 	/*
2788 	 * Generally speaking we now want to flush the media topology from
2789 	 * the iroot through to the inodes.  The flush stops at any inode
2790 	 * boundary, which allows the frontend to continue running concurrent
2791 	 * modifying operations on inodes (including kernel flushes of
2792 	 * buffers) without interfering with the main sync.
2793 	 *
2794 	 * Use the XOP interface to concurrently flush all nodes to
2795 	 * synchronize the PFSROOT subtopology to the media.  A standard
2796 	 * end-of-scan ENOENT error indicates cluster sufficiency.
2797 	 *
2798 	 * Note that this flush will not be visible on crash recovery until
2799 	 * we flush the super-root topology in the next loop.
2800 	 *
2801 	 * XXX For now wait for all flushes to complete.
2802 	 */
2803 	if (mp && (ip = pmp->iroot) != NULL) {
2804 		/*
2805 		 * If unmounting try to flush everything including any
2806 		 * sub-trees under inodes, just in case there is dangling
2807 		 * modified data, as a safety.  Otherwise just flush up to
2808 		 * the inodes in this stage.
2809 		 */
2810 		kprintf("MP & IROOT\n");
2811 #ifdef HAMMER2_DEBUG_SYNC
2812 		kprintf("FILESYSTEM SYNC STAGE 3 IROOT BEGIN\n");
2813 #endif
2814 		if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
2815 			xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
2816 						    HAMMER2_XOP_VOLHDR |
2817 						    HAMMER2_XOP_FSSYNC |
2818 						    HAMMER2_XOP_INODE_STOP);
2819 		} else {
2820 			xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
2821 						    HAMMER2_XOP_INODE_STOP |
2822 						    HAMMER2_XOP_VOLHDR |
2823 						    HAMMER2_XOP_FSSYNC |
2824 						    HAMMER2_XOP_INODE_STOP);
2825 		}
2826 		hammer2_xop_start(&xop->head, &hammer2_inode_flush_desc);
2827 		error = hammer2_xop_collect(&xop->head,
2828 					    HAMMER2_XOP_COLLECT_WAITALL);
2829 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2830 #ifdef HAMMER2_DEBUG_SYNC
2831 		kprintf("FILESYSTEM SYNC STAGE 3 IROOT END\n");
2832 #endif
2833 		if (error == HAMMER2_ERROR_ENOENT)
2834 			error = 0;
2835 		else
2836 			error = hammer2_error_to_errno(error);
2837 	} else {
2838 		error = 0;
2839 	}
2840 #endif
2841 	error = 0;	/* XXX */
2842 	hammer2_trans_done(pmp, HAMMER2_TRANS_ISFLUSH);
2843 
2844 	return (error);
2845 }
2846 
2847 static
2848 int
2849 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2850 {
2851 	hammer2_inode_t *ip;
2852 
2853 	KKASSERT(MAXFIDSZ >= 16);
2854 	ip = VTOI(vp);
2855 	fhp->fid_len = offsetof(struct fid, fid_data[16]);
2856 	fhp->fid_ext = 0;
2857 	((hammer2_tid_t *)fhp->fid_data)[0] = ip->meta.inum;
2858 	((hammer2_tid_t *)fhp->fid_data)[1] = 0;
2859 
2860 	return 0;
2861 }
2862 
2863 static
2864 int
2865 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2866 	       struct fid *fhp, struct vnode **vpp)
2867 {
2868 	hammer2_pfs_t *pmp;
2869 	hammer2_tid_t inum;
2870 	int error;
2871 
2872 	pmp = MPTOPMP(mp);
2873 	inum = ((hammer2_tid_t *)fhp->fid_data)[0] & HAMMER2_DIRHASH_USERMSK;
2874 	if (vpp) {
2875 		if (inum == 1)
2876 			error = hammer2_vfs_root(mp, vpp);
2877 		else
2878 			error = hammer2_vfs_vget(mp, NULL, inum, vpp);
2879 	} else {
2880 		error = 0;
2881 	}
2882 	if (error)
2883 		kprintf("fhtovp: %016jx -> %p, %d\n", inum, *vpp, error);
2884 	return error;
2885 }
2886 
2887 static
2888 int
2889 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2890 		 int *exflagsp, struct ucred **credanonp)
2891 {
2892 	hammer2_pfs_t *pmp;
2893 	struct netcred *np;
2894 	int error;
2895 
2896 	pmp = MPTOPMP(mp);
2897 	np = vfs_export_lookup(mp, &pmp->export, nam);
2898 	if (np) {
2899 		*exflagsp = np->netc_exflags;
2900 		*credanonp = &np->netc_anon;
2901 		error = 0;
2902 	} else {
2903 		error = EACCES;
2904 	}
2905 	return error;
2906 }
2907 
2908 /*
2909  * Support code for hammer2_vfs_mount().  Read, verify, and install the volume
2910  * header into the HMP
2911  */
2912 static
2913 int
2914 hammer2_install_volume_header(hammer2_dev_t *hmp)
2915 {
2916 	hammer2_volume_data_t *vd;
2917 	struct buf *bp;
2918 	hammer2_crc32_t crc0, crc, bcrc0, bcrc;
2919 	int error_reported;
2920 	int error;
2921 	int valid;
2922 	int i;
2923 
2924 	error_reported = 0;
2925 	error = 0;
2926 	valid = 0;
2927 	bp = NULL;
2928 
2929 	/*
2930 	 * There are up to 4 copies of the volume header (syncs iterate
2931 	 * between them so there is no single master).  We don't trust the
2932 	 * volu_size field so we don't know precisely how large the filesystem
2933 	 * is, so depend on the OS to return an error if we go beyond the
2934 	 * block device's EOF.
2935 	 */
2936 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
2937 		error = bread(hmp->devvp, i * HAMMER2_ZONE_BYTES64,
2938 			      HAMMER2_VOLUME_BYTES, &bp);
2939 		if (error) {
2940 			brelse(bp);
2941 			bp = NULL;
2942 			continue;
2943 		}
2944 
2945 		vd = (struct hammer2_volume_data *) bp->b_data;
2946 		if ((vd->magic != HAMMER2_VOLUME_ID_HBO) &&
2947 		    (vd->magic != HAMMER2_VOLUME_ID_ABO)) {
2948 			kprintf("hammer2: volume header #%d: bad magic\n", i);
2949 			brelse(bp);
2950 			bp = NULL;
2951 			continue;
2952 		}
2953 
2954 		if (vd->magic == HAMMER2_VOLUME_ID_ABO) {
2955 			/* XXX: Reversed-endianness filesystem */
2956 			kprintf("hammer2: volume header #%d: reverse-endian "
2957 				"filesystem detected\n", i);
2958 			brelse(bp);
2959 			bp = NULL;
2960 			continue;
2961 		}
2962 
2963 		crc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT0];
2964 		crc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC0_OFF,
2965 				      HAMMER2_VOLUME_ICRC0_SIZE);
2966 		bcrc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT1];
2967 		bcrc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC1_OFF,
2968 				       HAMMER2_VOLUME_ICRC1_SIZE);
2969 		if ((crc0 != crc) || (bcrc0 != bcrc)) {
2970 			kprintf("hammer2: volume header #%d: volume header crc "
2971 				"mismatch %08x/%08x\n",
2972 				i, crc0, crc);
2973 			error_reported = 1;
2974 			brelse(bp);
2975 			bp = NULL;
2976 			continue;
2977 		}
2978 		if (valid == 0 || hmp->voldata.mirror_tid < vd->mirror_tid) {
2979 			valid = 1;
2980 			hmp->voldata = *vd;
2981 			hmp->volhdrno = i;
2982 		}
2983 		brelse(bp);
2984 		bp = NULL;
2985 	}
2986 	if (valid) {
2987 		hmp->volsync = hmp->voldata;
2988 		hmp->free_reserved = hmp->voldata.allocator_size / 20;
2989 		error = 0;
2990 		if (error_reported || bootverbose || 1) { /* 1/DEBUG */
2991 			kprintf("hammer2: using volume header #%d\n",
2992 				hmp->volhdrno);
2993 		}
2994 	} else {
2995 		error = EINVAL;
2996 		kprintf("hammer2: no valid volume headers found!\n");
2997 	}
2998 	return (error);
2999 }
3000 
3001 /*
3002  * This handles hysteresis on regular file flushes.  Because the BIOs are
3003  * routed to a thread it is possible for an excessive number to build up
3004  * and cause long front-end stalls long before the runningbuffspace limit
3005  * is hit, so we implement hammer2_flush_pipe to control the
3006  * hysteresis.
3007  *
3008  * This is a particular problem when compression is used.
3009  */
3010 void
3011 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
3012 {
3013 	atomic_add_int(&pmp->count_lwinprog, 1);
3014 }
3015 
3016 void
3017 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
3018 {
3019 	int lwinprog;
3020 
3021 	lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
3022 	if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
3023 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
3024 		atomic_clear_int(&pmp->count_lwinprog,
3025 				 HAMMER2_LWINPROG_WAITING);
3026 		wakeup(&pmp->count_lwinprog);
3027 	}
3028 	if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
3029 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
3030 		atomic_clear_int(&pmp->count_lwinprog,
3031 				 HAMMER2_LWINPROG_WAITING0);
3032 		wakeup(&pmp->count_lwinprog);
3033 	}
3034 }
3035 
3036 void
3037 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
3038 {
3039 	int lwinprog;
3040 	int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
3041 				    HAMMER2_LWINPROG_WAITING0;
3042 
3043 	for (;;) {
3044 		lwinprog = pmp->count_lwinprog;
3045 		cpu_ccfence();
3046 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
3047 			break;
3048 		tsleep_interlock(&pmp->count_lwinprog, 0);
3049 		atomic_set_int(&pmp->count_lwinprog, lwflag);
3050 		lwinprog = pmp->count_lwinprog;
3051 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
3052 			break;
3053 		tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
3054 	}
3055 }
3056 
3057 /*
3058  * It is possible for an excessive number of dirty chains or dirty inodes
3059  * to build up.  When this occurs we start an asynchronous filesystem sync.
3060  * If the level continues to build up, we stall, waiting for it to drop,
3061  * with some hysteresis.
3062  *
3063  * This relies on the kernel calling hammer2_vfs_modifying() prior to
3064  * obtaining any vnode locks before making a modifying VOP call.
3065  */
3066 static int
3067 hammer2_vfs_modifying(struct mount *mp)
3068 {
3069 	if (mp->mnt_flag & MNT_RDONLY)
3070 		return EROFS;
3071 	hammer2_pfs_memory_wait(MPTOPMP(mp));
3072 
3073 	return 0;
3074 }
3075 
3076 /*
3077  * Initiate an asynchronous filesystem sync and, with hysteresis,
3078  * stall if the internal data structure count becomes too bloated.
3079  */
3080 void
3081 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
3082 {
3083 	uint32_t waiting;
3084 	int pcatch;
3085 	int error;
3086 
3087 	if (pmp == NULL || pmp->mp == NULL)
3088 		return;
3089 
3090 	for (;;) {
3091 		waiting = pmp->inmem_dirty_chains & HAMMER2_DIRTYCHAIN_MASK;
3092 		cpu_ccfence();
3093 
3094 		/*
3095 		 * Start the syncer running at 1/2 the limit
3096 		 */
3097 		if (waiting > hammer2_limit_dirty_chains / 2 ||
3098 		    pmp->sideq_count > hammer2_limit_dirty_inodes / 2) {
3099 			trigger_syncer(pmp->mp);
3100 		}
3101 
3102 		/*
3103 		 * Stall at the limit waiting for the counts to drop.
3104 		 * This code will typically be woken up once the count
3105 		 * drops below 3/4 the limit, or in one second.
3106 		 */
3107 		if (waiting < hammer2_limit_dirty_chains &&
3108 		    pmp->sideq_count < hammer2_limit_dirty_inodes) {
3109 			break;
3110 		}
3111 
3112 		pcatch = curthread->td_proc ? PCATCH : 0;
3113 
3114 		tsleep_interlock(&pmp->inmem_dirty_chains, pcatch);
3115 		atomic_set_int(&pmp->inmem_dirty_chains,
3116 			       HAMMER2_DIRTYCHAIN_WAITING);
3117 		if (waiting < hammer2_limit_dirty_chains &&
3118 		    pmp->sideq_count < hammer2_limit_dirty_inodes) {
3119 			break;
3120 		}
3121 		trigger_syncer(pmp->mp);
3122 		error = tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED | pcatch,
3123 			       "h2memw", hz);
3124 		if (error == ERESTART)
3125 			break;
3126 	}
3127 }
3128 
3129 /*
3130  * Wake up any stalled frontend ops waiting, with hysteresis, using
3131  * 2/3 of the limit.
3132  */
3133 void
3134 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp, int count)
3135 {
3136 	uint32_t waiting;
3137 
3138 	if (pmp) {
3139 		waiting = atomic_fetchadd_int(&pmp->inmem_dirty_chains, count);
3140 		/* don't need --waiting to test flag */
3141 
3142 		if ((waiting & HAMMER2_DIRTYCHAIN_WAITING) &&
3143 		    (pmp->inmem_dirty_chains & HAMMER2_DIRTYCHAIN_MASK) <=
3144 		    hammer2_limit_dirty_chains * 2 / 3 &&
3145 		    pmp->sideq_count <= hammer2_limit_dirty_inodes * 2 / 3) {
3146 			atomic_clear_int(&pmp->inmem_dirty_chains,
3147 					 HAMMER2_DIRTYCHAIN_WAITING);
3148 			wakeup(&pmp->inmem_dirty_chains);
3149 		}
3150 	}
3151 }
3152 
3153 void
3154 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
3155 {
3156 	if (pmp) {
3157 		atomic_add_int(&pmp->inmem_dirty_chains, 1);
3158 	}
3159 }
3160 
3161 /*
3162  * Volume header data locks
3163  */
3164 void
3165 hammer2_voldata_lock(hammer2_dev_t *hmp)
3166 {
3167 	lockmgr(&hmp->vollk, LK_EXCLUSIVE);
3168 }
3169 
3170 void
3171 hammer2_voldata_unlock(hammer2_dev_t *hmp)
3172 {
3173 	lockmgr(&hmp->vollk, LK_RELEASE);
3174 }
3175 
3176 void
3177 hammer2_voldata_modify(hammer2_dev_t *hmp)
3178 {
3179 	if ((hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) == 0) {
3180 		atomic_add_long(&hammer2_count_modified_chains, 1);
3181 		atomic_set_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
3182 		hammer2_pfs_memory_inc(hmp->vchain.pmp);
3183 	}
3184 }
3185 
3186 /*
3187  * Returns 0 if the filesystem has tons of free space
3188  * Returns 1 if the filesystem has less than 10% remaining
3189  * Returns 2 if the filesystem has less than 2%/5% (user/root) remaining.
3190  */
3191 int
3192 hammer2_vfs_enospace(hammer2_inode_t *ip, off_t bytes, struct ucred *cred)
3193 {
3194 	hammer2_pfs_t *pmp;
3195 	hammer2_dev_t *hmp;
3196 	hammer2_off_t free_reserved;
3197 	hammer2_off_t free_nominal;
3198 	int i;
3199 
3200 	pmp = ip->pmp;
3201 
3202 	if (pmp->free_ticks == 0 || pmp->free_ticks != ticks) {
3203 		free_reserved = HAMMER2_SEGSIZE;
3204 		free_nominal = 0x7FFFFFFFFFFFFFFFLLU;
3205 		for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
3206 			hmp = pmp->pfs_hmps[i];
3207 			if (hmp == NULL)
3208 				continue;
3209 			if (pmp->pfs_types[i] != HAMMER2_PFSTYPE_MASTER &&
3210 			    pmp->pfs_types[i] != HAMMER2_PFSTYPE_SOFT_MASTER)
3211 				continue;
3212 
3213 			if (free_nominal > hmp->voldata.allocator_free)
3214 				free_nominal = hmp->voldata.allocator_free;
3215 			if (free_reserved < hmp->free_reserved)
3216 				free_reserved = hmp->free_reserved;
3217 		}
3218 
3219 		/*
3220 		 * SMP races ok
3221 		 */
3222 		pmp->free_reserved = free_reserved;
3223 		pmp->free_nominal = free_nominal;
3224 		pmp->free_ticks = ticks;
3225 	} else {
3226 		free_reserved = pmp->free_reserved;
3227 		free_nominal = pmp->free_nominal;
3228 	}
3229 	if (cred && cred->cr_uid != 0) {
3230 		if ((int64_t)(free_nominal - bytes) <
3231 		    (int64_t)free_reserved) {
3232 			return 2;
3233 		}
3234 	} else {
3235 		if ((int64_t)(free_nominal - bytes) <
3236 		    (int64_t)free_reserved / 2) {
3237 			return 2;
3238 		}
3239 	}
3240 	if ((int64_t)(free_nominal - bytes) < (int64_t)free_reserved * 2)
3241 		return 1;
3242 	return 0;
3243 }
3244 
3245 /*
3246  * Debugging
3247  */
3248 void
3249 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int bi, int *countp,
3250 		   char pfx, u_int flags)
3251 {
3252 	hammer2_chain_t *scan;
3253 	hammer2_chain_t *parent;
3254 
3255 	--*countp;
3256 	if (*countp == 0) {
3257 		kprintf("%*.*s...\n", tab, tab, "");
3258 		return;
3259 	}
3260 	if (*countp < 0)
3261 		return;
3262 	kprintf("%*.*s%c-chain %p %s.%-3d %016jx %016jx/%-2d mir=%016jx\n",
3263 		tab, tab, "", pfx, chain,
3264 		hammer2_bref_type_str(chain->bref.type), bi,
3265 		chain->bref.data_off, chain->bref.key, chain->bref.keybits,
3266 		chain->bref.mirror_tid);
3267 
3268 	kprintf("%*.*s      [%08x] (%s) refs=%d",
3269 		tab, tab, "",
3270 		chain->flags,
3271 		((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
3272 		chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
3273 		chain->refs);
3274 
3275 	parent = chain->parent;
3276 	if (parent)
3277 		kprintf("\n%*.*s      p=%p [pflags %08x prefs %d]",
3278 			tab, tab, "",
3279 			parent, parent->flags, parent->refs);
3280 	if (RB_EMPTY(&chain->core.rbtree)) {
3281 		kprintf("\n");
3282 	} else {
3283 		int bi = 0;
3284 		kprintf(" {\n");
3285 		RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree) {
3286 			if ((scan->flags & flags) || flags == (u_int)-1) {
3287 				hammer2_dump_chain(scan, tab + 4, bi, countp,
3288 						   'a', flags);
3289 			}
3290 			bi++;
3291 		}
3292 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
3293 			kprintf("%*.*s}(%s)\n", tab, tab, "",
3294 				chain->data->ipdata.filename);
3295 		else
3296 			kprintf("%*.*s}\n", tab, tab, "");
3297 	}
3298 }
3299