xref: /dragonfly/sys/vfs/hammer2/hammer2_vfsops.c (revision 7d3e9a5b)
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/vfsops.h>
43 #include <sys/sysctl.h>
44 #include <sys/socket.h>
45 #include <sys/objcache.h>
46 #include <sys/proc.h>
47 #include <sys/lock.h>
48 #include <sys/file.h>
49 
50 #include "hammer2.h"
51 
52 TAILQ_HEAD(hammer2_mntlist, hammer2_dev);
53 static struct hammer2_mntlist hammer2_mntlist;
54 
55 struct hammer2_pfslist hammer2_pfslist;
56 struct hammer2_pfslist hammer2_spmplist;
57 struct lock hammer2_mntlk;
58 
59 int hammer2_supported_version = HAMMER2_VOL_VERSION_DEFAULT;
60 int hammer2_debug;
61 int hammer2_aux_flags;
62 int hammer2_xop_nthreads;
63 int hammer2_xop_sgroups;
64 int hammer2_xop_xgroups;
65 int hammer2_xop_xbase;
66 int hammer2_xop_mod;
67 long hammer2_debug_inode;
68 int hammer2_cluster_meta_read = 1;	/* physical read-ahead */
69 int hammer2_cluster_data_read = 4;	/* physical read-ahead */
70 int hammer2_cluster_write = 0;		/* physical write clustering */
71 int hammer2_dedup_enable = 1;
72 int hammer2_always_compress = 0;	/* always try to compress */
73 int hammer2_flush_pipe = 100;
74 int hammer2_dio_count;
75 int hammer2_dio_limit = 256;
76 int hammer2_bulkfree_tps = 5000;
77 int hammer2_spread_workers;
78 long hammer2_chain_allocs;
79 long hammer2_limit_dirty_chains;
80 long hammer2_limit_dirty_inodes;
81 long hammer2_count_modified_chains;
82 long hammer2_iod_file_read;
83 long hammer2_iod_meta_read;
84 long hammer2_iod_indr_read;
85 long hammer2_iod_fmap_read;
86 long hammer2_iod_volu_read;
87 long hammer2_iod_file_write;
88 long hammer2_iod_file_wembed;
89 long hammer2_iod_file_wzero;
90 long hammer2_iod_file_wdedup;
91 long hammer2_iod_meta_write;
92 long hammer2_iod_indr_write;
93 long hammer2_iod_fmap_write;
94 long hammer2_iod_volu_write;
95 static long hammer2_iod_inode_creates;
96 static long hammer2_iod_inode_deletes;
97 
98 long hammer2_process_icrc32;
99 long hammer2_process_xxhash64;
100 
101 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
102 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
103 		"Buffer used for compression.");
104 
105 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
106 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
107 		"Buffer used for decompression.");
108 
109 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
110 
111 SYSCTL_INT(_vfs_hammer2, OID_AUTO, supported_version, CTLFLAG_RD,
112 	   &hammer2_supported_version, 0, "");
113 SYSCTL_INT(_vfs_hammer2, OID_AUTO, aux_flags, CTLFLAG_RW,
114 	   &hammer2_aux_flags, 0, "");
115 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
116 	   &hammer2_debug, 0, "");
117 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, debug_inode, CTLFLAG_RW,
118 	   &hammer2_debug_inode, 0, "");
119 SYSCTL_INT(_vfs_hammer2, OID_AUTO, spread_workers, CTLFLAG_RW,
120 	   &hammer2_spread_workers, 0, "");
121 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_meta_read, CTLFLAG_RW,
122 	   &hammer2_cluster_meta_read, 0, "");
123 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_data_read, CTLFLAG_RW,
124 	   &hammer2_cluster_data_read, 0, "");
125 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_write, CTLFLAG_RW,
126 	   &hammer2_cluster_write, 0, "");
127 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dedup_enable, CTLFLAG_RW,
128 	   &hammer2_dedup_enable, 0, "");
129 SYSCTL_INT(_vfs_hammer2, OID_AUTO, always_compress, CTLFLAG_RW,
130 	   &hammer2_always_compress, 0, "");
131 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
132 	   &hammer2_flush_pipe, 0, "");
133 SYSCTL_INT(_vfs_hammer2, OID_AUTO, bulkfree_tps, CTLFLAG_RW,
134 	   &hammer2_bulkfree_tps, 0, "");
135 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_allocs, CTLFLAG_RW,
136 	   &hammer2_chain_allocs, 0, "");
137 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
138 	   &hammer2_limit_dirty_chains, 0, "");
139 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_inodes, CTLFLAG_RW,
140 	   &hammer2_limit_dirty_inodes, 0, "");
141 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, count_modified_chains, CTLFLAG_RW,
142 	   &hammer2_count_modified_chains, 0, "");
143 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
144 	   &hammer2_dio_count, 0, "");
145 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_limit, CTLFLAG_RW,
146 	   &hammer2_dio_limit, 0, "");
147 
148 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
149 	   &hammer2_iod_file_read, 0, "");
150 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
151 	   &hammer2_iod_meta_read, 0, "");
152 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
153 	   &hammer2_iod_indr_read, 0, "");
154 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
155 	   &hammer2_iod_fmap_read, 0, "");
156 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
157 	   &hammer2_iod_volu_read, 0, "");
158 
159 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
160 	   &hammer2_iod_file_write, 0, "");
161 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
162 	   &hammer2_iod_file_wembed, 0, "");
163 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
164 	   &hammer2_iod_file_wzero, 0, "");
165 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
166 	   &hammer2_iod_file_wdedup, 0, "");
167 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
168 	   &hammer2_iod_meta_write, 0, "");
169 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
170 	   &hammer2_iod_indr_write, 0, "");
171 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
172 	   &hammer2_iod_fmap_write, 0, "");
173 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
174 	   &hammer2_iod_volu_write, 0, "");
175 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_inode_creates, CTLFLAG_RW,
176 	   &hammer2_iod_inode_creates, 0, "");
177 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_inode_deletes, CTLFLAG_RW,
178 	   &hammer2_iod_inode_deletes, 0, "");
179 
180 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, process_icrc32, CTLFLAG_RW,
181 	   &hammer2_process_icrc32, 0, "");
182 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, process_xxhash64, CTLFLAG_RW,
183 	   &hammer2_process_xxhash64, 0, "");
184 
185 static int hammer2_vfs_init(struct vfsconf *conf);
186 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
187 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
188 				struct ucred *cred);
189 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
190 				struct ucred *);
191 static int hammer2_recovery(hammer2_dev_t *hmp);
192 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
193 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
194 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
195 				struct ucred *cred);
196 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
197 				struct ucred *cred);
198 static int hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
199 				struct fid *fhp, struct vnode **vpp);
200 static int hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp);
201 static int hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
202 				int *exflagsp, struct ucred **credanonp);
203 static int hammer2_vfs_modifying(struct mount *mp);
204 
205 static void hammer2_update_pmps(hammer2_dev_t *hmp);
206 
207 static void hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp);
208 static void hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp,
209 				hammer2_dev_t *hmp);
210 static int hammer2_fixup_pfses(hammer2_dev_t *hmp);
211 
212 /*
213  * HAMMER2 vfs operations.
214  */
215 static struct vfsops hammer2_vfsops = {
216 	.vfs_flags	= 0,
217 	.vfs_init	= hammer2_vfs_init,
218 	.vfs_uninit	= hammer2_vfs_uninit,
219 	.vfs_sync	= hammer2_vfs_sync,
220 	.vfs_mount	= hammer2_vfs_mount,
221 	.vfs_unmount	= hammer2_vfs_unmount,
222 	.vfs_root 	= hammer2_vfs_root,
223 	.vfs_statfs	= hammer2_vfs_statfs,
224 	.vfs_statvfs	= hammer2_vfs_statvfs,
225 	.vfs_vget	= hammer2_vfs_vget,
226 	.vfs_vptofh	= hammer2_vfs_vptofh,
227 	.vfs_fhtovp	= hammer2_vfs_fhtovp,
228 	.vfs_checkexp	= hammer2_vfs_checkexp,
229 	.vfs_modifying	= hammer2_vfs_modifying
230 };
231 
232 MALLOC_DEFINE(M_HAMMER2, "HAMMER2-mount", "");
233 
234 VFS_SET(hammer2_vfsops, hammer2, VFCF_MPSAFE);
235 MODULE_VERSION(hammer2, 1);
236 
237 static
238 int
239 hammer2_vfs_init(struct vfsconf *conf)
240 {
241 	static struct objcache_malloc_args margs_read;
242 	static struct objcache_malloc_args margs_write;
243 	static struct objcache_malloc_args margs_vop;
244 
245 	int error;
246 	int mod;
247 
248 	error = 0;
249 	kmalloc_raise_limit(M_HAMMER2, 0);	/* unlimited */
250 
251 	/*
252 	 * hammer2_xop_nthreads must be a multiple of ncpus,
253 	 * minimum 2 * ncpus.
254 	 */
255 	mod = ncpus;
256 	hammer2_xop_mod = mod;
257 	hammer2_xop_nthreads = mod * 2;
258 	while (hammer2_xop_nthreads / mod < HAMMER2_XOPGROUPS_MIN ||
259 	       hammer2_xop_nthreads < HAMMER2_XOPTHREADS_MIN)
260         {
261 		hammer2_xop_nthreads += mod;
262 	}
263 	hammer2_xop_sgroups = hammer2_xop_nthreads / mod / 2;
264 	hammer2_xop_xgroups = hammer2_xop_nthreads / mod - hammer2_xop_sgroups;
265 	hammer2_xop_xbase = hammer2_xop_sgroups * mod;
266 
267 	/*
268 	 * A large DIO cache is needed to retain dedup enablement masks.
269 	 * The bulkfree code clears related masks as part of the disk block
270 	 * recycling algorithm, preventing it from being used for a later
271 	 * dedup.
272 	 *
273 	 * NOTE: A large buffer cache can actually interfere with dedup
274 	 *	 operation because we dedup based on media physical buffers
275 	 *	 and not logical buffers.  Try to make the DIO case large
276 	 *	 enough to avoid this problem, but also cap it.
277 	 */
278 	hammer2_dio_limit = nbuf * 2;
279 	if (hammer2_dio_limit > 100000)
280 		hammer2_dio_limit = 100000;
281 
282 	if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
283 		error = EINVAL;
284 	if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
285 		error = EINVAL;
286 	if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
287 		error = EINVAL;
288 
289 	if (error)
290 		kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
291 
292 	margs_read.objsize = 65536;
293 	margs_read.mtype = M_HAMMER2_DEBUFFER;
294 
295 	margs_write.objsize = 32768;
296 	margs_write.mtype = M_HAMMER2_CBUFFER;
297 
298 	margs_vop.objsize = sizeof(hammer2_xop_t);
299 	margs_vop.mtype = M_HAMMER2;
300 
301 	/*
302 	 * Note thaht for the XOPS cache we want backing store allocations
303 	 * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
304 	 * confusion), so use the backing store function that does it.  This
305 	 * means that initial XOPS objects are zerod but REUSED objects are
306 	 * not.  So we are responsible for cleaning the object up sufficiently
307 	 * for our needs before objcache_put()ing it back (typically just the
308 	 * FIFO indices).
309 	 */
310 	cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
311 				0, 1, NULL, NULL, NULL,
312 				objcache_malloc_alloc,
313 				objcache_malloc_free,
314 				&margs_read);
315 	cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
316 				0, 1, NULL, NULL, NULL,
317 				objcache_malloc_alloc,
318 				objcache_malloc_free,
319 				&margs_write);
320 	cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
321 				0, 1, NULL, NULL, NULL,
322 				objcache_malloc_alloc_zero,
323 				objcache_malloc_free,
324 				&margs_vop);
325 
326 
327 	lockinit(&hammer2_mntlk, "mntlk", 0, 0);
328 	TAILQ_INIT(&hammer2_mntlist);
329 	TAILQ_INIT(&hammer2_pfslist);
330 	TAILQ_INIT(&hammer2_spmplist);
331 
332 	hammer2_limit_dirty_chains = maxvnodes / 10;
333 	if (hammer2_limit_dirty_chains > HAMMER2_LIMIT_DIRTY_CHAINS)
334 		hammer2_limit_dirty_chains = HAMMER2_LIMIT_DIRTY_CHAINS;
335 	if (hammer2_limit_dirty_chains < 1000)
336 		hammer2_limit_dirty_chains = 1000;
337 
338 	hammer2_limit_dirty_inodes = maxvnodes / 25;
339 	if (hammer2_limit_dirty_inodes < 100)
340 		hammer2_limit_dirty_inodes = 100;
341 	if (hammer2_limit_dirty_inodes > HAMMER2_LIMIT_DIRTY_INODES)
342 		hammer2_limit_dirty_inodes = HAMMER2_LIMIT_DIRTY_INODES;
343 
344 	return (error);
345 }
346 
347 static
348 int
349 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
350 {
351 	objcache_destroy(cache_buffer_read);
352 	objcache_destroy(cache_buffer_write);
353 	objcache_destroy(cache_xops);
354 	return 0;
355 }
356 
357 /*
358  * Core PFS allocator.  Used to allocate or reference the pmp structure
359  * for PFS cluster mounts and the spmp structure for media (hmp) structures.
360  * The pmp can be passed in or loaded by this function using the chain and
361  * inode data.
362  *
363  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
364  * transactions.  Note that synchronization does not use this field.
365  * (typically frontend operations and synchronization cannot run on the
366  * same PFS node at the same time).
367  *
368  * XXX check locking
369  */
370 hammer2_pfs_t *
371 hammer2_pfsalloc(hammer2_chain_t *chain,
372 		 const hammer2_inode_data_t *ripdata,
373 		 hammer2_tid_t modify_tid, hammer2_dev_t *force_local)
374 {
375 	hammer2_pfs_t *pmp;
376 	hammer2_inode_t *iroot;
377 	int count;
378 	int i;
379 	int j;
380 
381 	pmp = NULL;
382 
383 	/*
384 	 * Locate or create the PFS based on the cluster id.  If ripdata
385 	 * is NULL this is a spmp which is unique and is always allocated.
386 	 *
387 	 * If the device is mounted in local mode all PFSs are considered
388 	 * independent and not part of any cluster (for debugging only).
389 	 */
390 	if (ripdata) {
391 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
392 			if (force_local != pmp->force_local)
393 				continue;
394 			if (force_local == NULL &&
395 			    bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
396 				 sizeof(pmp->pfs_clid)) == 0) {
397 					break;
398 			} else if (force_local && pmp->pfs_names[0] &&
399 			    strcmp(pmp->pfs_names[0], ripdata->filename) == 0) {
400 					break;
401 			}
402 		}
403 	}
404 
405 	if (pmp == NULL) {
406 		pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
407 		pmp->force_local = force_local;
408 		hammer2_trans_manage_init(pmp);
409 		kmalloc_create_obj(&pmp->minode, "HAMMER2-inodes",
410 				   sizeof(struct hammer2_inode));
411 		lockinit(&pmp->lock, "pfslk", 0, 0);
412 		spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
413 		spin_init(&pmp->xop_spin, "h2xop");
414 		spin_init(&pmp->lru_spin, "h2lru");
415 		RB_INIT(&pmp->inum_tree);
416 		TAILQ_INIT(&pmp->syncq);
417 		TAILQ_INIT(&pmp->depq);
418 		TAILQ_INIT(&pmp->lru_list);
419 		spin_init(&pmp->list_spin, "h2pfsalloc_list");
420 
421 		/*
422 		 * Save the last media transaction id for the flusher.  Set
423 		 * initial
424 		 */
425 		if (ripdata) {
426 			pmp->pfs_clid = ripdata->meta.pfs_clid;
427 			TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
428 		} else {
429 			pmp->flags |= HAMMER2_PMPF_SPMP;
430 			TAILQ_INSERT_TAIL(&hammer2_spmplist, pmp, mntentry);
431 		}
432 
433 		/*
434 		 * The synchronization thread may start too early, make
435 		 * sure it stays frozen until we are ready to let it go.
436 		 * XXX
437 		 */
438 		/*
439 		pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
440 					 HAMMER2_THREAD_REMASTER;
441 		*/
442 	}
443 
444 	/*
445 	 * Create the PFS's root inode and any missing XOP helper threads.
446 	 */
447 	if ((iroot = pmp->iroot) == NULL) {
448 		iroot = hammer2_inode_get(pmp, NULL, 1, -1);
449 		if (ripdata)
450 			iroot->meta = ripdata->meta;
451 		pmp->iroot = iroot;
452 		hammer2_inode_ref(iroot);
453 		hammer2_inode_unlock(iroot);
454 	}
455 
456 	/*
457 	 * Stop here if no chain is passed in.
458 	 */
459 	if (chain == NULL)
460 		goto done;
461 
462 	/*
463 	 * When a chain is passed in we must add it to the PFS's root
464 	 * inode, update pmp->pfs_types[], and update the syncronization
465 	 * threads.
466 	 *
467 	 * When forcing local mode, mark the PFS as a MASTER regardless.
468 	 *
469 	 * At the moment empty spots can develop due to removals or failures.
470 	 * Ultimately we want to re-fill these spots but doing so might
471 	 * confused running code. XXX
472 	 */
473 	hammer2_inode_ref(iroot);
474 	hammer2_mtx_ex(&iroot->lock);
475 	j = iroot->cluster.nchains;
476 
477 	if (j == HAMMER2_MAXCLUSTER) {
478 		kprintf("hammer2_pfsalloc: cluster full!\n");
479 		/* XXX fatal error? */
480 	} else {
481 		KKASSERT(chain->pmp == NULL);
482 		chain->pmp = pmp;
483 		hammer2_chain_ref(chain);
484 		iroot->cluster.array[j].chain = chain;
485 		if (force_local)
486 			pmp->pfs_types[j] = HAMMER2_PFSTYPE_MASTER;
487 		else
488 			pmp->pfs_types[j] = ripdata->meta.pfs_type;
489 		pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
490 		pmp->pfs_hmps[j] = chain->hmp;
491 		hammer2_spin_ex(&pmp->inum_spin);
492 		pmp->pfs_iroot_blocksets[j] = chain->data->ipdata.u.blockset;
493 		hammer2_spin_unex(&pmp->inum_spin);
494 
495 		/*
496 		 * If the PFS is already mounted we must account
497 		 * for the mount_count here.
498 		 */
499 		if (pmp->mp)
500 			++chain->hmp->mount_count;
501 
502 		/*
503 		 * May have to fixup dirty chain tracking.  Previous
504 		 * pmp was NULL so nothing to undo.
505 		 */
506 		if (chain->flags & HAMMER2_CHAIN_MODIFIED)
507 			hammer2_pfs_memory_inc(pmp);
508 		++j;
509 	}
510 	iroot->cluster.nchains = j;
511 
512 	/*
513 	 * Update nmasters from any PFS inode which is part of the cluster.
514 	 * It is possible that this will result in a value which is too
515 	 * high.  MASTER PFSs are authoritative for pfs_nmasters and will
516 	 * override this value later on.
517 	 *
518 	 * (This informs us of masters that might not currently be
519 	 *  discoverable by this mount).
520 	 */
521 	if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
522 		pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
523 	}
524 
525 	/*
526 	 * Count visible masters.  Masters are usually added with
527 	 * ripdata->meta.pfs_nmasters set to 1.  This detects when there
528 	 * are more (XXX and must update the master inodes).
529 	 */
530 	count = 0;
531 	for (i = 0; i < iroot->cluster.nchains; ++i) {
532 		if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
533 			++count;
534 	}
535 	if (pmp->pfs_nmasters < count)
536 		pmp->pfs_nmasters = count;
537 
538 	/*
539 	 * Create missing synchronization and support threads.
540 	 *
541 	 * Single-node masters (including snapshots) have nothing to
542 	 * synchronize and do not require this thread.
543 	 *
544 	 * Multi-node masters or any number of soft masters, slaves, copy,
545 	 * or other PFS types need the thread.
546 	 *
547 	 * Each thread is responsible for its particular cluster index.
548 	 * We use independent threads so stalls or mismatches related to
549 	 * any given target do not affect other targets.
550 	 */
551 	for (i = 0; i < iroot->cluster.nchains; ++i) {
552 		/*
553 		 * Single-node masters (including snapshots) have nothing
554 		 * to synchronize and will make direct xops support calls,
555 		 * thus they do not require this thread.
556 		 *
557 		 * Note that there can be thousands of snapshots.  We do not
558 		 * want to create thousands of threads.
559 		 */
560 		if (pmp->pfs_nmasters <= 1 &&
561 		    pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
562 			continue;
563 		}
564 
565 		/*
566 		 * Sync support thread
567 		 */
568 		if (pmp->sync_thrs[i].td == NULL) {
569 			hammer2_thr_create(&pmp->sync_thrs[i], pmp, NULL,
570 					   "h2nod", i, -1,
571 					   hammer2_primary_sync_thread);
572 		}
573 	}
574 
575 	/*
576 	 * Create missing Xop threads
577 	 *
578 	 * NOTE: We create helper threads for all mounted PFSs or any
579 	 *	 PFSs with 2+ nodes (so the sync thread can update them,
580 	 *	 even if not mounted).
581 	 */
582 	if (pmp->mp || iroot->cluster.nchains >= 2)
583 		hammer2_xop_helper_create(pmp);
584 
585 	hammer2_mtx_unlock(&iroot->lock);
586 	hammer2_inode_drop(iroot);
587 done:
588 	return pmp;
589 }
590 
591 /*
592  * Deallocate an element of a probed PFS.  If destroying and this is a
593  * MASTER, adjust nmasters.
594  *
595  * This function does not physically destroy the PFS element in its device
596  * under the super-root  (see hammer2_ioctl_pfs_delete()).
597  */
598 void
599 hammer2_pfsdealloc(hammer2_pfs_t *pmp, int clindex, int destroying)
600 {
601 	hammer2_inode_t *iroot;
602 	hammer2_chain_t *chain;
603 	int j;
604 
605 	/*
606 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
607 	 * by the flush code.
608 	 */
609 	iroot = pmp->iroot;
610 	if (iroot) {
611 		/*
612 		 * Stop synchronizing
613 		 *
614 		 * XXX flush after acquiring the iroot lock.
615 		 * XXX clean out the cluster index from all inode structures.
616 		 */
617 		hammer2_thr_delete(&pmp->sync_thrs[clindex]);
618 
619 		/*
620 		 * Remove the cluster index from the group.  If destroying
621 		 * the PFS and this is a master, adjust pfs_nmasters.
622 		 */
623 		hammer2_mtx_ex(&iroot->lock);
624 		chain = iroot->cluster.array[clindex].chain;
625 		iroot->cluster.array[clindex].chain = NULL;
626 
627 		switch(pmp->pfs_types[clindex]) {
628 		case HAMMER2_PFSTYPE_MASTER:
629 			if (destroying && pmp->pfs_nmasters > 0)
630 				--pmp->pfs_nmasters;
631 			/* XXX adjust ripdata->meta.pfs_nmasters */
632 			break;
633 		default:
634 			break;
635 		}
636 		pmp->pfs_types[clindex] = HAMMER2_PFSTYPE_NONE;
637 
638 		hammer2_mtx_unlock(&iroot->lock);
639 
640 		/*
641 		 * Release the chain.
642 		 */
643 		if (chain) {
644 			atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
645 			hammer2_chain_drop(chain);
646 		}
647 
648 		/*
649 		 * Terminate all XOP threads for the cluster index.
650 		 */
651 		if (pmp->xop_groups) {
652 			for (j = 0; j < hammer2_xop_nthreads; ++j) {
653 				hammer2_thr_delete(
654 					&pmp->xop_groups[j].thrs[clindex]);
655 			}
656 		}
657 	}
658 }
659 
660 /*
661  * Destroy a PFS, typically only occurs after the last mount on a device
662  * has gone away.
663  */
664 static void
665 hammer2_pfsfree(hammer2_pfs_t *pmp)
666 {
667 	hammer2_inode_t *iroot;
668 	hammer2_chain_t *chain;
669 	int chains_still_present = 0;
670 	int i;
671 	int j;
672 
673 	/*
674 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
675 	 * by the flush code.
676 	 */
677 	if (pmp->flags & HAMMER2_PMPF_SPMP)
678 		TAILQ_REMOVE(&hammer2_spmplist, pmp, mntentry);
679 	else
680 		TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
681 
682 	/*
683 	 * Cleanup chains remaining on LRU list.
684 	 */
685 	hammer2_spin_ex(&pmp->lru_spin);
686 	while ((chain = TAILQ_FIRST(&pmp->lru_list)) != NULL) {
687 		KKASSERT(chain->flags & HAMMER2_CHAIN_ONLRU);
688 		atomic_add_int(&pmp->lru_count, -1);
689 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_ONLRU);
690 		TAILQ_REMOVE(&pmp->lru_list, chain, lru_node);
691 		hammer2_chain_ref(chain);
692 		hammer2_spin_unex(&pmp->lru_spin);
693 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
694 		hammer2_chain_drop(chain);
695 		hammer2_spin_ex(&pmp->lru_spin);
696 	}
697 	hammer2_spin_unex(&pmp->lru_spin);
698 
699 	/*
700 	 * Clean up iroot
701 	 */
702 	iroot = pmp->iroot;
703 	if (iroot) {
704 		for (i = 0; i < iroot->cluster.nchains; ++i) {
705 			hammer2_thr_delete(&pmp->sync_thrs[i]);
706 			if (pmp->xop_groups) {
707 				for (j = 0; j < hammer2_xop_nthreads; ++j)
708 					hammer2_thr_delete(
709 						&pmp->xop_groups[j].thrs[i]);
710 			}
711 			chain = iroot->cluster.array[i].chain;
712 			if (chain && !RB_EMPTY(&chain->core.rbtree)) {
713 				kprintf("hammer2: Warning pmp %p still "
714 					"has active chains\n", pmp);
715 				chains_still_present = 1;
716 			}
717 		}
718 		KASSERT(iroot->refs == 1,
719 			("PMP->IROOT %p REFS WRONG %d", iroot, iroot->refs));
720 
721 		/* ref for iroot */
722 		hammer2_inode_drop(iroot);
723 		pmp->iroot = NULL;
724 	}
725 
726 	/*
727 	 * Free remaining pmp resources
728 	 */
729 	if (chains_still_present) {
730 		kprintf("hammer2: cannot free pmp %p, still in use\n", pmp);
731 	} else {
732 		kmalloc_destroy_obj(&pmp->minode);
733 		kfree(pmp, M_HAMMER2);
734 	}
735 }
736 
737 /*
738  * Remove all references to hmp from the pfs list.  Any PFS which becomes
739  * empty is terminated and freed.
740  *
741  * XXX inefficient.
742  */
743 static void
744 hammer2_pfsfree_scan(hammer2_dev_t *hmp, int which)
745 {
746 	hammer2_pfs_t *pmp;
747 	hammer2_inode_t *iroot;
748 	hammer2_chain_t *rchain;
749 	int i;
750 	int j;
751 	struct hammer2_pfslist *wlist;
752 
753 	if (which == 0)
754 		wlist = &hammer2_pfslist;
755 	else
756 		wlist = &hammer2_spmplist;
757 again:
758 	TAILQ_FOREACH(pmp, wlist, mntentry) {
759 		if ((iroot = pmp->iroot) == NULL)
760 			continue;
761 
762 		/*
763 		 * Determine if this PFS is affected.  If it is we must
764 		 * freeze all management threads and lock its iroot.
765 		 *
766 		 * Freezing a management thread forces it idle, operations
767 		 * in-progress will be aborted and it will have to start
768 		 * over again when unfrozen, or exit if told to exit.
769 		 */
770 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
771 			if (pmp->pfs_hmps[i] == hmp)
772 				break;
773 		}
774 		if (i == HAMMER2_MAXCLUSTER)
775 			continue;
776 
777 		hammer2_vfs_sync_pmp(pmp, MNT_WAIT);
778 
779 		/*
780 		 * Make sure all synchronization threads are locked
781 		 * down.
782 		 */
783 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
784 			if (pmp->pfs_hmps[i] == NULL)
785 				continue;
786 			hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
787 			if (pmp->xop_groups) {
788 				for (j = 0; j < hammer2_xop_nthreads; ++j) {
789 					hammer2_thr_freeze_async(
790 						&pmp->xop_groups[j].thrs[i]);
791 				}
792 			}
793 		}
794 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
795 			if (pmp->pfs_hmps[i] == NULL)
796 				continue;
797 			hammer2_thr_freeze(&pmp->sync_thrs[i]);
798 			if (pmp->xop_groups) {
799 				for (j = 0; j < hammer2_xop_nthreads; ++j) {
800 					hammer2_thr_freeze(
801 						&pmp->xop_groups[j].thrs[i]);
802 				}
803 			}
804 		}
805 
806 		/*
807 		 * Lock the inode and clean out matching chains.
808 		 * Note that we cannot use hammer2_inode_lock_*()
809 		 * here because that would attempt to validate the
810 		 * cluster that we are in the middle of ripping
811 		 * apart.
812 		 *
813 		 * WARNING! We are working directly on the inodes
814 		 *	    embedded cluster.
815 		 */
816 		hammer2_mtx_ex(&iroot->lock);
817 
818 		/*
819 		 * Remove the chain from matching elements of the PFS.
820 		 */
821 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
822 			if (pmp->pfs_hmps[i] != hmp)
823 				continue;
824 			hammer2_thr_delete(&pmp->sync_thrs[i]);
825 			if (pmp->xop_groups) {
826 				for (j = 0; j < hammer2_xop_nthreads; ++j) {
827 					hammer2_thr_delete(
828 						&pmp->xop_groups[j].thrs[i]);
829 				}
830 			}
831 			rchain = iroot->cluster.array[i].chain;
832 			iroot->cluster.array[i].chain = NULL;
833 			pmp->pfs_types[i] = 0;
834 			if (pmp->pfs_names[i]) {
835 				kfree(pmp->pfs_names[i], M_HAMMER2);
836 				pmp->pfs_names[i] = NULL;
837 			}
838 			if (rchain) {
839 				hammer2_chain_drop(rchain);
840 				/* focus hint */
841 				if (iroot->cluster.focus == rchain)
842 					iroot->cluster.focus = NULL;
843 			}
844 			pmp->pfs_hmps[i] = NULL;
845 		}
846 		hammer2_mtx_unlock(&iroot->lock);
847 
848 		/*
849 		 * Cleanup trailing chains.  Gaps may remain.
850 		 */
851 		for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
852 			if (pmp->pfs_hmps[i])
853 				break;
854 		}
855 		iroot->cluster.nchains = i + 1;
856 
857 		/*
858 		 * If the PMP has no elements remaining we can destroy it.
859 		 * (this will transition management threads from frozen->exit).
860 		 */
861 		if (iroot->cluster.nchains == 0) {
862 			/*
863 			 * If this was the hmp's spmp, we need to clean
864 			 * a little more stuff out.
865 			 */
866 			if (hmp->spmp == pmp) {
867 				hmp->spmp = NULL;
868 				hmp->vchain.pmp = NULL;
869 				hmp->fchain.pmp = NULL;
870 			}
871 
872 			/*
873 			 * Free the pmp and restart the loop
874 			 */
875 			KKASSERT(TAILQ_EMPTY(&pmp->syncq));
876 			KKASSERT(TAILQ_EMPTY(&pmp->depq));
877 			hammer2_pfsfree(pmp);
878 			goto again;
879 		}
880 
881 		/*
882 		 * If elements still remain we need to set the REMASTER
883 		 * flag and unfreeze it.
884 		 */
885 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
886 			if (pmp->pfs_hmps[i] == NULL)
887 				continue;
888 			hammer2_thr_remaster(&pmp->sync_thrs[i]);
889 			hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
890 			if (pmp->xop_groups) {
891 				for (j = 0; j < hammer2_xop_nthreads; ++j) {
892 					hammer2_thr_remaster(
893 						&pmp->xop_groups[j].thrs[i]);
894 					hammer2_thr_unfreeze(
895 						&pmp->xop_groups[j].thrs[i]);
896 				}
897 			}
898 		}
899 	}
900 }
901 
902 /*
903  * Mount or remount HAMMER2 fileystem from physical media
904  *
905  *	mountroot
906  *		mp		mount point structure
907  *		path		NULL
908  *		data		<unused>
909  *		cred		<unused>
910  *
911  *	mount
912  *		mp		mount point structure
913  *		path		path to mount point
914  *		data		pointer to argument structure in user space
915  *			volume	volume path (device@LABEL form)
916  *			hflags	user mount flags
917  *		cred		user credentials
918  *
919  * RETURNS:	0	Success
920  *		!0	error number
921  */
922 static
923 int
924 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
925 		  struct ucred *cred)
926 {
927 	struct hammer2_mount_info info;
928 	hammer2_pfs_t *pmp;
929 	hammer2_pfs_t *spmp;
930 	hammer2_dev_t *hmp, *hmp_tmp;
931 	hammer2_dev_t *force_local;
932 	hammer2_key_t key_next;
933 	hammer2_key_t key_dummy;
934 	hammer2_key_t lhc;
935 	hammer2_chain_t *parent;
936 	hammer2_chain_t *chain;
937 	const hammer2_inode_data_t *ripdata;
938 	hammer2_blockref_t bref;
939 	hammer2_devvp_list_t devvpl;
940 	hammer2_devvp_t *e, *e_tmp;
941 	struct file *fp;
942 	char devstr[MNAMELEN];
943 	size_t size;
944 	size_t done;
945 	char *dev;
946 	char *label;
947 	int ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
948 	int error;
949 	int i;
950 
951 	hmp = NULL;
952 	pmp = NULL;
953 	dev = NULL;
954 	label = NULL;
955 	bzero(&info, sizeof(info));
956 
957 	if (path) {
958 		/*
959 		 * Non-root mount or updating a mount
960 		 */
961 		error = copyin(data, &info, sizeof(info));
962 		if (error)
963 			return (error);
964 	}
965 
966 	if (mp->mnt_flag & MNT_UPDATE) {
967 		/*
968 		 * Update mount.  Note that pmp->iroot->cluster is
969 		 * an inode-embedded cluster and thus cannot be
970 		 * directly locked.
971 		 *
972 		 * XXX HAMMER2 needs to implement NFS export via
973 		 *     mountctl.
974 		 */
975 		hammer2_cluster_t *cluster;
976 
977 		pmp = MPTOPMP(mp);
978 		pmp->hflags = info.hflags;
979 		cluster = &pmp->iroot->cluster;
980 		for (i = 0; i < cluster->nchains; ++i) {
981 			if (cluster->array[i].chain == NULL)
982 				continue;
983 			hmp = cluster->array[i].chain->hmp;
984 			error = hammer2_remount(hmp, mp, path, cred);
985 			if (error)
986 				break;
987 		}
988 
989 		return error;
990 	}
991 
992 	if (path == NULL) {
993 		/*
994 		 * Root mount
995 		 */
996 		info.cluster_fd = -1;
997 		ksnprintf(devstr, sizeof(devstr), "%s",
998 			  mp->mnt_stat.f_mntfromname);
999 		done = strlen(devstr) + 1;
1000 		kprintf("hammer2_mount: root devstr=\"%s\"\n", devstr);
1001 	} else {
1002 		error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
1003 		if (error)
1004 			return (error);
1005 		kprintf("hammer2_mount: devstr=\"%s\"\n", devstr);
1006 	}
1007 
1008 	/*
1009 	 * Extract device and label, automatically mount @BOOT, @ROOT, or @DATA
1010 	 * if no label specified, based on the partition id.  Error out if no
1011 	 * label or device (with partition id) is specified.  This is strictly
1012 	 * a convenience to match the default label created by newfs_hammer2,
1013 	 * our preference is that a label always be specified.
1014 	 *
1015 	 * NOTE: We allow 'mount @LABEL <blah>'... that is, a mount command
1016 	 *	 that does not specify a device, as long as some H2 label
1017 	 *	 has already been mounted from that device.  This makes
1018 	 *	 mounting snapshots a lot easier.
1019 	 */
1020 	dev = devstr;
1021 	label = strchr(devstr, '@');
1022 	if (label && ((label + 1) - dev) > done) {
1023 		kprintf("hammer2_mount: bad label %s/%zd\n", devstr, done);
1024 		return (EINVAL);
1025 	}
1026 	if (label == NULL || label[1] == 0) {
1027 		char slice;
1028 
1029 		if (label == NULL)
1030 			label = devstr + strlen(devstr);
1031 		else
1032 			*label = '\0';		/* clean up trailing @ */
1033 
1034 		slice = label[-1];
1035 		switch(slice) {
1036 		case 'a':
1037 			label = "BOOT";
1038 			break;
1039 		case 'd':
1040 			label = "ROOT";
1041 			break;
1042 		default:
1043 			label = "DATA";
1044 			break;
1045 		}
1046 	} else {
1047 		*label = '\0';
1048 		label++;
1049 	}
1050 
1051 	kprintf("hammer2_mount: dev=\"%s\" label=\"%s\" rdonly=%d\n",
1052 		dev, label, ronly);
1053 
1054 	/*
1055 	 * Initialize all device vnodes.
1056 	 */
1057 	TAILQ_INIT(&devvpl);
1058 	error = hammer2_init_devvp(dev, path == NULL, &devvpl);
1059 	if (error) {
1060 		kprintf("hammer2: failed to initialize devvp in %s\n", dev);
1061 		hammer2_cleanup_devvp(&devvpl);
1062 		return error;
1063 	}
1064 
1065 	/*
1066 	 * Determine if the device has already been mounted.  After this
1067 	 * check hmp will be non-NULL if we are doing the second or more
1068 	 * hammer2 mounts from the same device.
1069 	 */
1070 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1071 	if (!TAILQ_EMPTY(&devvpl)) {
1072 		/*
1073 		 * Match the device.  Due to the way devfs works,
1074 		 * we may not be able to directly match the vnode pointer,
1075 		 * so also check to see if the underlying device matches.
1076 		 */
1077 		TAILQ_FOREACH(hmp_tmp, &hammer2_mntlist, mntentry) {
1078 			TAILQ_FOREACH(e_tmp, &hmp_tmp->devvpl, entry) {
1079 				int devvp_found = 0;
1080 				TAILQ_FOREACH(e, &devvpl, entry) {
1081 					KKASSERT(e->devvp);
1082 					if (e_tmp->devvp == e->devvp)
1083 						devvp_found = 1;
1084 					if (e_tmp->devvp->v_rdev &&
1085 					    e_tmp->devvp->v_rdev == e->devvp->v_rdev)
1086 						devvp_found = 1;
1087 				}
1088 				if (!devvp_found)
1089 					goto next_hmp;
1090 			}
1091 			hmp = hmp_tmp;
1092 			kprintf("hammer2_mount: hmp=%p matched\n", hmp);
1093 			break;
1094 next_hmp:
1095 			continue;
1096 		}
1097 
1098 		/*
1099 		 * If no match this may be a fresh H2 mount, make sure
1100 		 * the device is not mounted on anything else.
1101 		 */
1102 		if (hmp == NULL) {
1103 			TAILQ_FOREACH(e, &devvpl, entry) {
1104 				struct vnode *devvp = e->devvp;
1105 				KKASSERT(devvp);
1106 				error = vfs_mountedon(devvp);
1107 				if (error) {
1108 					kprintf("hammer2_mount: %s mounted %d\n",
1109 						e->path, error);
1110 					hammer2_cleanup_devvp(&devvpl);
1111 					lockmgr(&hammer2_mntlk, LK_RELEASE);
1112 					return error;
1113 				}
1114 			}
1115 		}
1116 	} else {
1117 		/*
1118 		 * Match the label to a pmp already probed.
1119 		 */
1120 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
1121 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
1122 				if (pmp->pfs_names[i] &&
1123 				    strcmp(pmp->pfs_names[i], label) == 0) {
1124 					hmp = pmp->pfs_hmps[i];
1125 					break;
1126 				}
1127 			}
1128 			if (hmp)
1129 				break;
1130 		}
1131 		if (hmp == NULL) {
1132 			kprintf("hammer2_mount: PFS label \"%s\" not found\n",
1133 				label);
1134 			hammer2_cleanup_devvp(&devvpl);
1135 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1136 			return ENOENT;
1137 		}
1138 	}
1139 
1140 	/*
1141 	 * Open the device if this isn't a secondary mount and construct
1142 	 * the H2 device mount (hmp).
1143 	 */
1144 	if (hmp == NULL) {
1145 		hammer2_chain_t *schain;
1146 		hammer2_xop_head_t xop;
1147 
1148 		/*
1149 		 * Now open the device
1150 		 */
1151 		KKASSERT(!TAILQ_EMPTY(&devvpl));
1152 		if (error == 0) {
1153 			error = hammer2_open_devvp(&devvpl, ronly);
1154 			if (error) {
1155 				hammer2_close_devvp(&devvpl, ronly);
1156 				hammer2_cleanup_devvp(&devvpl);
1157 				lockmgr(&hammer2_mntlk, LK_RELEASE);
1158 				return error;
1159 			}
1160 		}
1161 
1162 		/*
1163 		 * Construct volumes and link with device vnodes.
1164 		 */
1165 		hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
1166 		hmp->devvp = NULL;
1167 		error = hammer2_init_volumes(mp, &devvpl, hmp->volumes,
1168 					     &hmp->voldata, &hmp->volhdrno,
1169 					     &hmp->devvp);
1170 		if (error) {
1171 			hammer2_close_devvp(&devvpl, ronly);
1172 			hammer2_cleanup_devvp(&devvpl);
1173 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1174 			kfree(hmp, M_HAMMER2);
1175 			return error;
1176 		}
1177 		if (!hmp->devvp) {
1178 			kprintf("hammer2: failed to initialize root volume\n");
1179 			hammer2_unmount_helper(mp, NULL, hmp);
1180 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1181 			hammer2_vfs_unmount(mp, MNT_FORCE);
1182 			return EINVAL;
1183 		}
1184 
1185 		ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
1186 		hmp->ronly = ronly;
1187 		hmp->hflags = info.hflags & HMNT2_DEVFLAGS;
1188 		kmalloc_create_obj(&hmp->mchain, "HAMMER2-chains",
1189 				   sizeof(struct hammer2_chain));
1190 		kmalloc_create_obj(&hmp->mio, "HAMMER2-dio",
1191 				   sizeof(struct hammer2_io));
1192 		kmalloc_create(&hmp->mmsg, "HAMMER2-msg");
1193 		TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
1194 		RB_INIT(&hmp->iotree);
1195 		spin_init(&hmp->io_spin, "h2mount_io");
1196 		spin_init(&hmp->list_spin, "h2mount_list");
1197 
1198 		lockinit(&hmp->vollk, "h2vol", 0, 0);
1199 		lockinit(&hmp->bulklk, "h2bulk", 0, 0);
1200 		lockinit(&hmp->bflock, "h2bflk", 0, 0);
1201 
1202 		/*
1203 		 * vchain setup. vchain.data is embedded.
1204 		 * vchain.refs is initialized and will never drop to 0.
1205 		 *
1206 		 * NOTE! voldata is not yet loaded.
1207 		 */
1208 		hmp->vchain.hmp = hmp;
1209 		hmp->vchain.refs = 1;
1210 		hmp->vchain.data = (void *)&hmp->voldata;
1211 		hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
1212 		hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1213 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1214 		hammer2_chain_core_init(&hmp->vchain);
1215 
1216 		/*
1217 		 * fchain setup.  fchain.data is embedded.
1218 		 * fchain.refs is initialized and will never drop to 0.
1219 		 *
1220 		 * The data is not used but needs to be initialized to
1221 		 * pass assertion muster.  We use this chain primarily
1222 		 * as a placeholder for the freemap's top-level radix tree
1223 		 * so it does not interfere with the volume's topology
1224 		 * radix tree.
1225 		 */
1226 		hmp->fchain.hmp = hmp;
1227 		hmp->fchain.refs = 1;
1228 		hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
1229 		hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
1230 		hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1231 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1232 		hmp->fchain.bref.methods =
1233 			HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
1234 			HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
1235 		hammer2_chain_core_init(&hmp->fchain);
1236 
1237 		/*
1238 		 * Initialize volume header related fields.
1239 		 */
1240 		KKASSERT(hmp->voldata.magic == HAMMER2_VOLUME_ID_HBO ||
1241 			 hmp->voldata.magic == HAMMER2_VOLUME_ID_ABO);
1242 		hmp->volsync = hmp->voldata;
1243 		hmp->free_reserved = hmp->voldata.allocator_size / 20;
1244 		/*
1245 		 * Must use hmp instead of volume header for these two
1246 		 * in order to handle volume versions transparently.
1247 		 */
1248 		if (hmp->voldata.version >= HAMMER2_VOL_VERSION_MULTI_VOLUMES) {
1249 			hmp->nvolumes = hmp->voldata.nvolumes;
1250 			hmp->total_size = hmp->voldata.total_size;
1251 		} else {
1252 			hmp->nvolumes = 1;
1253 			hmp->total_size = hmp->voldata.volu_size;
1254 		}
1255 		KKASSERT(hmp->nvolumes > 0);
1256 
1257 		/*
1258 		 * Move devvpl entries to hmp.
1259 		 */
1260 		TAILQ_INIT(&hmp->devvpl);
1261 		while ((e = TAILQ_FIRST(&devvpl)) != NULL) {
1262 			TAILQ_REMOVE(&devvpl, e, entry);
1263 			TAILQ_INSERT_TAIL(&hmp->devvpl, e, entry);
1264 		}
1265 		KKASSERT(TAILQ_EMPTY(&devvpl));
1266 		KKASSERT(!TAILQ_EMPTY(&hmp->devvpl));
1267 
1268 		/*
1269 		 * Really important to get these right or the flush and
1270 		 * teardown code will get confused.
1271 		 */
1272 		hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0, NULL);
1273 		spmp = hmp->spmp;
1274 		spmp->pfs_hmps[0] = hmp;
1275 
1276 		/*
1277 		 * Dummy-up vchain and fchain's modify_tid.  mirror_tid
1278 		 * is inherited from the volume header.
1279 		 */
1280 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1281 		hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
1282 		hmp->vchain.pmp = spmp;
1283 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1284 		hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
1285 		hmp->fchain.pmp = spmp;
1286 
1287 		/*
1288 		 * First locate the super-root inode, which is key 0
1289 		 * relative to the volume header's blockset.
1290 		 *
1291 		 * Then locate the root inode by scanning the directory keyspace
1292 		 * represented by the label.
1293 		 */
1294 		parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1295 		schain = hammer2_chain_lookup(&parent, &key_dummy,
1296 				      HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
1297 				      &error, 0);
1298 		hammer2_chain_lookup_done(parent);
1299 		if (schain == NULL) {
1300 			kprintf("hammer2_mount: invalid super-root\n");
1301 			hammer2_unmount_helper(mp, NULL, hmp);
1302 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1303 			hammer2_vfs_unmount(mp, MNT_FORCE);
1304 			return EINVAL;
1305 		}
1306 		if (schain->error) {
1307 			kprintf("hammer2_mount: error %s reading super-root\n",
1308 				hammer2_error_str(schain->error));
1309 			hammer2_chain_unlock(schain);
1310 			hammer2_chain_drop(schain);
1311 			schain = NULL;
1312 			hammer2_unmount_helper(mp, NULL, hmp);
1313 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1314 			hammer2_vfs_unmount(mp, MNT_FORCE);
1315 			return EINVAL;
1316 		}
1317 
1318 		/*
1319 		 * The super-root always uses an inode_tid of 1 when
1320 		 * creating PFSs.
1321 		 */
1322 		spmp->inode_tid = 1;
1323 		spmp->modify_tid = schain->bref.modify_tid + 1;
1324 
1325 		/*
1326 		 * Sanity-check schain's pmp and finish initialization.
1327 		 * Any chain belonging to the super-root topology should
1328 		 * have a NULL pmp (not even set to spmp).
1329 		 */
1330 		ripdata = &schain->data->ipdata;
1331 		KKASSERT(schain->pmp == NULL);
1332 		spmp->pfs_clid = ripdata->meta.pfs_clid;
1333 
1334 		/*
1335 		 * Replace the dummy spmp->iroot with a real one.  It's
1336 		 * easier to just do a wholesale replacement than to try
1337 		 * to update the chain and fixup the iroot fields.
1338 		 *
1339 		 * The returned inode is locked with the supplied cluster.
1340 		 */
1341 		hammer2_dummy_xop_from_chain(&xop, schain);
1342 		hammer2_inode_drop(spmp->iroot);
1343 		spmp->iroot = NULL;
1344 		spmp->iroot = hammer2_inode_get(spmp, &xop, -1, -1);
1345 		spmp->spmp_hmp = hmp;
1346 		spmp->pfs_types[0] = ripdata->meta.pfs_type;
1347 		spmp->pfs_hmps[0] = hmp;
1348 		hammer2_inode_ref(spmp->iroot);
1349 		hammer2_inode_unlock(spmp->iroot);
1350 		hammer2_cluster_unlock(&xop.cluster);
1351 		hammer2_chain_drop(schain);
1352 		/* do not call hammer2_cluster_drop() on an embedded cluster */
1353 		schain = NULL;	/* now invalid */
1354 		/* leave spmp->iroot with one ref */
1355 
1356 		if (!hmp->ronly) {
1357 			error = hammer2_recovery(hmp);
1358 			if (error == 0)
1359 				error |= hammer2_fixup_pfses(hmp);
1360 			/* XXX do something with error */
1361 		}
1362 		hammer2_update_pmps(hmp);
1363 		hammer2_iocom_init(hmp);
1364 		hammer2_bulkfree_init(hmp);
1365 
1366 		/*
1367 		 * Ref the cluster management messaging descriptor.  The mount
1368 		 * program deals with the other end of the communications pipe.
1369 		 *
1370 		 * Root mounts typically do not supply one.
1371 		 */
1372 		if (info.cluster_fd >= 0) {
1373 			fp = holdfp(curthread, info.cluster_fd, -1);
1374 			if (fp) {
1375 				hammer2_cluster_reconnect(hmp, fp);
1376 			} else {
1377 				kprintf("hammer2_mount: bad cluster_fd!\n");
1378 			}
1379 		}
1380 	} else {
1381 		spmp = hmp->spmp;
1382 		if (info.hflags & HMNT2_DEVFLAGS) {
1383 			kprintf("hammer2_mount: Warning: mount flags pertaining "
1384 				"to the whole device may only be specified "
1385 				"on the first mount of the device: %08x\n",
1386 				info.hflags & HMNT2_DEVFLAGS);
1387 		}
1388 	}
1389 
1390 	/*
1391 	 * Force local mount (disassociate all PFSs from their clusters).
1392 	 * Used primarily for debugging.
1393 	 */
1394 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1395 
1396 	/*
1397 	 * Lookup the mount point under the media-localized super-root.
1398 	 * Scanning hammer2_pfslist doesn't help us because it represents
1399 	 * PFS cluster ids which can aggregate several named PFSs together.
1400 	 *
1401 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1402 	 * up later on.
1403 	 */
1404 	hammer2_inode_lock(spmp->iroot, 0);
1405 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1406 	lhc = hammer2_dirhash(label, strlen(label));
1407 	chain = hammer2_chain_lookup(&parent, &key_next,
1408 				     lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1409 				     &error, 0);
1410 	while (chain) {
1411 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1412 		    strcmp(label, chain->data->ipdata.filename) == 0) {
1413 			break;
1414 		}
1415 		chain = hammer2_chain_next(&parent, chain, &key_next,
1416 					    key_next,
1417 					    lhc + HAMMER2_DIRHASH_LOMASK,
1418 					    &error, 0);
1419 	}
1420 	if (parent) {
1421 		hammer2_chain_unlock(parent);
1422 		hammer2_chain_drop(parent);
1423 	}
1424 	hammer2_inode_unlock(spmp->iroot);
1425 
1426 	/*
1427 	 * PFS could not be found?
1428 	 */
1429 	if (chain == NULL) {
1430 		hammer2_unmount_helper(mp, NULL, hmp);
1431 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1432 		hammer2_vfs_unmount(mp, MNT_FORCE);
1433 
1434 		if (error) {
1435 			kprintf("hammer2_mount: PFS label I/O error\n");
1436 			return EINVAL;
1437 		} else {
1438 			kprintf("hammer2_mount: PFS label \"%s\" not found\n",
1439 				label);
1440 			return ENOENT;
1441 		}
1442 	}
1443 
1444 	/*
1445 	 * Acquire the pmp structure (it should have already been allocated
1446 	 * via hammer2_update_pmps() so do not pass cluster in to add to
1447 	 * available chains).
1448 	 *
1449 	 * Check if the cluster has already been mounted.  A cluster can
1450 	 * only be mounted once, use null mounts to mount additional copies.
1451 	 */
1452 	if (chain->error) {
1453 		kprintf("hammer2_mount: PFS label I/O error\n");
1454 	} else {
1455 		ripdata = &chain->data->ipdata;
1456 		bref = chain->bref;
1457 		pmp = hammer2_pfsalloc(NULL, ripdata,
1458 				       bref.modify_tid, force_local);
1459 	}
1460 	hammer2_chain_unlock(chain);
1461 	hammer2_chain_drop(chain);
1462 
1463 	/*
1464 	 * Finish the mount
1465 	 */
1466         kprintf("hammer2_mount: hmp=%p pmp=%p\n", hmp, pmp);
1467 
1468 	if (pmp->mp) {
1469 		kprintf("hammer2_mount: PFS already mounted!\n");
1470 		hammer2_unmount_helper(mp, NULL, hmp);
1471 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1472 		hammer2_vfs_unmount(mp, MNT_FORCE);
1473 
1474 		return EBUSY;
1475 	}
1476 
1477 	pmp->hflags = info.hflags;
1478         mp->mnt_flag |= MNT_LOCAL;
1479         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1480         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1481 
1482         /*
1483          * required mount structure initializations
1484          */
1485         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1486         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1487 
1488         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1489         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1490 
1491         /*
1492          * Optional fields
1493          */
1494         mp->mnt_iosize_max = MAXPHYS;
1495 
1496 	/*
1497 	 * Connect up mount pointers.
1498 	 */
1499 	hammer2_mount_helper(mp, pmp);
1500         lockmgr(&hammer2_mntlk, LK_RELEASE);
1501 
1502 	/*
1503 	 * Finish setup
1504 	 */
1505 	vfs_getnewfsid(mp);
1506 	vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1507 	vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1508 	vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1509 
1510 	if (path) {
1511 		copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1512 			  MNAMELEN - 1, &size);
1513 		bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1514 	} /* else root mount, already in there */
1515 
1516 	bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1517 	if (path) {
1518 		copyinstr(path, mp->mnt_stat.f_mntonname,
1519 			  sizeof(mp->mnt_stat.f_mntonname) - 1,
1520 			  &size);
1521 	} else {
1522 		/* root mount */
1523 		mp->mnt_stat.f_mntonname[0] = '/';
1524 	}
1525 
1526 	/*
1527 	 * Initial statfs to prime mnt_stat.
1528 	 */
1529 	hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1530 
1531 	return 0;
1532 }
1533 
1534 /*
1535  * Scan PFSs under the super-root and create hammer2_pfs structures.
1536  */
1537 static
1538 void
1539 hammer2_update_pmps(hammer2_dev_t *hmp)
1540 {
1541 	const hammer2_inode_data_t *ripdata;
1542 	hammer2_chain_t *parent;
1543 	hammer2_chain_t *chain;
1544 	hammer2_blockref_t bref;
1545 	hammer2_dev_t *force_local;
1546 	hammer2_pfs_t *spmp;
1547 	hammer2_pfs_t *pmp;
1548 	hammer2_key_t key_next;
1549 	int error;
1550 
1551 	/*
1552 	 * Force local mount (disassociate all PFSs from their clusters).
1553 	 * Used primarily for debugging.
1554 	 */
1555 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1556 
1557 	/*
1558 	 * Lookup mount point under the media-localized super-root.
1559 	 *
1560 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1561 	 * up later on.
1562 	 */
1563 	spmp = hmp->spmp;
1564 	hammer2_inode_lock(spmp->iroot, 0);
1565 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1566 	chain = hammer2_chain_lookup(&parent, &key_next,
1567 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1568 					 &error, 0);
1569 	while (chain) {
1570 		if (chain->error) {
1571 			kprintf("I/O error scanning PFS labels\n");
1572 		} else if (chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
1573 			kprintf("Non inode chain type %d under super-root\n",
1574 				chain->bref.type);
1575 		} else {
1576 			ripdata = &chain->data->ipdata;
1577 			bref = chain->bref;
1578 			pmp = hammer2_pfsalloc(chain, ripdata,
1579 					       bref.modify_tid, force_local);
1580 		}
1581 		chain = hammer2_chain_next(&parent, chain, &key_next,
1582 					   key_next, HAMMER2_KEY_MAX,
1583 					   &error, 0);
1584 	}
1585 	if (parent) {
1586 		hammer2_chain_unlock(parent);
1587 		hammer2_chain_drop(parent);
1588 	}
1589 	hammer2_inode_unlock(spmp->iroot);
1590 }
1591 
1592 static
1593 int
1594 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1595 		struct ucred *cred)
1596 {
1597 	hammer2_volume_t *vol;
1598 	struct vnode *devvp;
1599 	int i, error, result = 0;
1600 
1601 	if (!(hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)))
1602 		return 0;
1603 
1604 	for (i = 0; i < hmp->nvolumes; ++i) {
1605 		vol = &hmp->volumes[i];
1606 		devvp = vol->dev->devvp;
1607 		KKASSERT(devvp);
1608 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1609 		VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, NULL);
1610 		vn_unlock(devvp);
1611 		error = 0;
1612 		if (vol->id == HAMMER2_ROOT_VOLUME) {
1613 			error = hammer2_recovery(hmp);
1614 			if (error == 0)
1615 				error |= hammer2_fixup_pfses(hmp);
1616 		}
1617 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1618 		if (error == 0) {
1619 			VOP_CLOSE(devvp, FREAD, NULL);
1620 		} else {
1621 			VOP_CLOSE(devvp, FREAD | FWRITE, NULL);
1622 		}
1623 		vn_unlock(devvp);
1624 		result |= error;
1625 	}
1626 	if (result == 0) {
1627 		kprintf("hammer2: enable read/write\n");
1628 		hmp->ronly = 0;
1629 	}
1630 
1631 	return result;
1632 }
1633 
1634 static
1635 int
1636 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1637 {
1638 	hammer2_pfs_t *pmp;
1639 	int flags;
1640 	int error = 0;
1641 
1642 	pmp = MPTOPMP(mp);
1643 
1644 	if (pmp == NULL)
1645 		return(0);
1646 
1647 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1648 
1649 	/*
1650 	 * If mount initialization proceeded far enough we must flush
1651 	 * its vnodes and sync the underlying mount points.  Three syncs
1652 	 * are required to fully flush the filesystem (freemap updates lag
1653 	 * by one flush, and one extra for safety).
1654 	 */
1655 	if (mntflags & MNT_FORCE)
1656 		flags = FORCECLOSE;
1657 	else
1658 		flags = 0;
1659 	if (pmp->iroot) {
1660 		error = vflush(mp, 0, flags);
1661 		if (error)
1662 			goto failed;
1663 		hammer2_vfs_sync(mp, MNT_WAIT);
1664 		hammer2_vfs_sync(mp, MNT_WAIT);
1665 		hammer2_vfs_sync(mp, MNT_WAIT);
1666 	}
1667 
1668 	/*
1669 	 * Cleanup the frontend support XOPS threads
1670 	 */
1671 	hammer2_xop_helper_cleanup(pmp);
1672 
1673 	if (pmp->mp)
1674 		hammer2_unmount_helper(mp, pmp, NULL);
1675 
1676 	error = 0;
1677 failed:
1678 	lockmgr(&hammer2_mntlk, LK_RELEASE);
1679 
1680 	return (error);
1681 }
1682 
1683 /*
1684  * Mount helper, hook the system mount into our PFS.
1685  * The mount lock is held.
1686  *
1687  * We must bump the mount_count on related devices for any
1688  * mounted PFSs.
1689  */
1690 static
1691 void
1692 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1693 {
1694 	hammer2_cluster_t *cluster;
1695 	hammer2_chain_t *rchain;
1696 	int i;
1697 
1698         mp->mnt_data = (qaddr_t)pmp;
1699 	pmp->mp = mp;
1700 
1701 	/*
1702 	 * After pmp->mp is set we have to adjust hmp->mount_count.
1703 	 */
1704 	cluster = &pmp->iroot->cluster;
1705 	for (i = 0; i < cluster->nchains; ++i) {
1706 		rchain = cluster->array[i].chain;
1707 		if (rchain == NULL)
1708 			continue;
1709 		++rchain->hmp->mount_count;
1710 	}
1711 
1712 	/*
1713 	 * Create missing Xop threads
1714 	 */
1715 	hammer2_xop_helper_create(pmp);
1716 }
1717 
1718 /*
1719  * Mount helper, unhook the system mount from our PFS.
1720  * The mount lock is held.
1721  *
1722  * If hmp is supplied a mount responsible for being the first to open
1723  * the block device failed and the block device and all PFSs using the
1724  * block device must be cleaned up.
1725  *
1726  * If pmp is supplied multiple devices might be backing the PFS and each
1727  * must be disconnected.  This might not be the last PFS using some of the
1728  * underlying devices.  Also, we have to adjust our hmp->mount_count
1729  * accounting for the devices backing the pmp which is now undergoing an
1730  * unmount.
1731  */
1732 static
1733 void
1734 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1735 {
1736 	hammer2_cluster_t *cluster;
1737 	hammer2_chain_t *rchain;
1738 	int dumpcnt;
1739 	int i;
1740 
1741 	/*
1742 	 * If no device supplied this is a high-level unmount and we have to
1743 	 * to disconnect the mount, adjust mount_count, and locate devices
1744 	 * that might now have no mounts.
1745 	 */
1746 	if (pmp) {
1747 		KKASSERT(hmp == NULL);
1748 		KKASSERT(MPTOPMP(mp) == pmp);
1749 		pmp->mp = NULL;
1750 		mp->mnt_data = NULL;
1751 
1752 		/*
1753 		 * After pmp->mp is cleared we have to account for
1754 		 * mount_count.
1755 		 */
1756 		cluster = &pmp->iroot->cluster;
1757 		for (i = 0; i < cluster->nchains; ++i) {
1758 			rchain = cluster->array[i].chain;
1759 			if (rchain == NULL)
1760 				continue;
1761 			--rchain->hmp->mount_count;
1762 			/* scrapping hmp now may invalidate the pmp */
1763 		}
1764 again:
1765 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1766 			if (hmp->mount_count == 0) {
1767 				hammer2_unmount_helper(NULL, NULL, hmp);
1768 				goto again;
1769 			}
1770 		}
1771 		return;
1772 	}
1773 
1774 	/*
1775 	 * Try to terminate the block device.  We can't terminate it if
1776 	 * there are still PFSs referencing it.
1777 	 */
1778 	if (hmp->mount_count)
1779 		return;
1780 
1781 	/*
1782 	 * Decomission the network before we start messing with the
1783 	 * device and PFS.
1784 	 */
1785 	hammer2_iocom_uninit(hmp);
1786 
1787 	hammer2_bulkfree_uninit(hmp);
1788 	hammer2_pfsfree_scan(hmp, 0);
1789 
1790 	/*
1791 	 * Cycle the volume data lock as a safety (probably not needed any
1792 	 * more).  To ensure everything is out we need to flush at least
1793 	 * three times.  (1) The running of the sideq can dirty the
1794 	 * filesystem, (2) A normal flush can dirty the freemap, and
1795 	 * (3) ensure that the freemap is fully synchronized.
1796 	 *
1797 	 * The next mount's recovery scan can clean everything up but we want
1798 	 * to leave the filesystem in a 100% clean state on a normal unmount.
1799 	 */
1800 #if 0
1801 	hammer2_voldata_lock(hmp);
1802 	hammer2_voldata_unlock(hmp);
1803 #endif
1804 
1805 	/*
1806 	 * Flush whatever is left.  Unmounted but modified PFS's might still
1807 	 * have some dirty chains on them.
1808 	 */
1809 	hammer2_chain_lock(&hmp->vchain, HAMMER2_RESOLVE_ALWAYS);
1810 	hammer2_chain_lock(&hmp->fchain, HAMMER2_RESOLVE_ALWAYS);
1811 
1812 	if (hmp->fchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1813 		hammer2_voldata_modify(hmp);
1814 		hammer2_flush(&hmp->fchain, HAMMER2_FLUSH_TOP |
1815 					    HAMMER2_FLUSH_ALL);
1816 	}
1817 	hammer2_chain_unlock(&hmp->fchain);
1818 
1819 	if (hmp->vchain.flags & HAMMER2_CHAIN_FLUSH_MASK) {
1820 		hammer2_flush(&hmp->vchain, HAMMER2_FLUSH_TOP |
1821 					    HAMMER2_FLUSH_ALL);
1822 	}
1823 	hammer2_chain_unlock(&hmp->vchain);
1824 
1825 	if ((hmp->vchain.flags | hmp->fchain.flags) &
1826 	    HAMMER2_CHAIN_FLUSH_MASK) {
1827 		kprintf("hammer2_unmount: chains left over after final sync\n");
1828 		kprintf("    vchain %08x\n", hmp->vchain.flags);
1829 		kprintf("    fchain %08x\n", hmp->fchain.flags);
1830 
1831 		if (hammer2_debug & 0x0010)
1832 			Debugger("entered debugger");
1833 	}
1834 
1835 	hammer2_pfsfree_scan(hmp, 1);
1836 
1837 	KKASSERT(hmp->spmp == NULL);
1838 
1839 	/*
1840 	 * Finish up with the device vnode
1841 	 */
1842 	if (!TAILQ_EMPTY(&hmp->devvpl)) {
1843 		hammer2_close_devvp(&hmp->devvpl, hmp->ronly);
1844 		hammer2_cleanup_devvp(&hmp->devvpl);
1845 	}
1846 	KKASSERT(TAILQ_EMPTY(&hmp->devvpl));
1847 
1848 	/*
1849 	 * Clear vchain/fchain flags that might prevent final cleanup
1850 	 * of these chains.
1851 	 */
1852 	if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1853 		atomic_add_long(&hammer2_count_modified_chains, -1);
1854 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1855 		hammer2_pfs_memory_wakeup(hmp->vchain.pmp, -1);
1856 	}
1857 	if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1858 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_UPDATE);
1859 	}
1860 
1861 	if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1862 		atomic_add_long(&hammer2_count_modified_chains, -1);
1863 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_MODIFIED);
1864 		hammer2_pfs_memory_wakeup(hmp->fchain.pmp, -1);
1865 	}
1866 	if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1867 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_UPDATE);
1868 	}
1869 
1870 	/*
1871 	 * Final drop of embedded freemap root chain to
1872 	 * clean up fchain.core (fchain structure is not
1873 	 * flagged ALLOCATED so it is cleaned out and then
1874 	 * left to rot).
1875 	 */
1876 	hammer2_chain_drop(&hmp->fchain);
1877 
1878 	/*
1879 	 * Final drop of embedded volume root chain to clean
1880 	 * up vchain.core (vchain structure is not flagged
1881 	 * ALLOCATED so it is cleaned out and then left to
1882 	 * rot).
1883 	 */
1884 	dumpcnt = 50;
1885 	hammer2_dump_chain(&hmp->vchain, 0, 0, &dumpcnt, 'v', (u_int)-1);
1886 	dumpcnt = 50;
1887 	hammer2_dump_chain(&hmp->fchain, 0, 0, &dumpcnt, 'f', (u_int)-1);
1888 
1889 	hammer2_chain_drop(&hmp->vchain);
1890 
1891 	hammer2_io_cleanup(hmp, &hmp->iotree);
1892 	if (hmp->iofree_count) {
1893 		kprintf("io_cleanup: %d I/O's left hanging\n",
1894 			hmp->iofree_count);
1895 	}
1896 
1897 	TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1898 	kmalloc_destroy_obj(&hmp->mchain);
1899 	kmalloc_destroy_obj(&hmp->mio);
1900 	kmalloc_destroy(&hmp->mmsg);
1901 	kfree(hmp, M_HAMMER2);
1902 }
1903 
1904 int
1905 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1906 		 ino_t ino, struct vnode **vpp)
1907 {
1908 	hammer2_xop_lookup_t *xop;
1909 	hammer2_pfs_t *pmp;
1910 	hammer2_inode_t *ip;
1911 	hammer2_tid_t inum;
1912 	int error;
1913 
1914 	inum = (hammer2_tid_t)ino & HAMMER2_DIRHASH_USERMSK;
1915 
1916 	error = 0;
1917 	pmp = MPTOPMP(mp);
1918 
1919 	/*
1920 	 * Easy if we already have it cached
1921 	 */
1922 	ip = hammer2_inode_lookup(pmp, inum);
1923 	if (ip) {
1924 		hammer2_inode_lock(ip, HAMMER2_RESOLVE_SHARED);
1925 		*vpp = hammer2_igetv(ip, &error);
1926 		hammer2_inode_unlock(ip);
1927 		hammer2_inode_drop(ip);		/* from lookup */
1928 
1929 		return error;
1930 	}
1931 
1932 	/*
1933 	 * Otherwise we have to find the inode
1934 	 */
1935 	xop = hammer2_xop_alloc(pmp->iroot, 0);
1936 	xop->lhc = inum;
1937 	hammer2_xop_start(&xop->head, &hammer2_lookup_desc);
1938 	error = hammer2_xop_collect(&xop->head, 0);
1939 
1940 	if (error == 0)
1941 		ip = hammer2_inode_get(pmp, &xop->head, -1, -1);
1942 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1943 
1944 	if (ip) {
1945 		*vpp = hammer2_igetv(ip, &error);
1946 		hammer2_inode_unlock(ip);
1947 	} else {
1948 		*vpp = NULL;
1949 		error = ENOENT;
1950 	}
1951 	return (error);
1952 }
1953 
1954 static
1955 int
1956 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1957 {
1958 	hammer2_pfs_t *pmp;
1959 	struct vnode *vp;
1960 	int error;
1961 
1962 	pmp = MPTOPMP(mp);
1963 	if (pmp->iroot == NULL) {
1964 		kprintf("hammer2 (%s): no root inode\n",
1965 			mp->mnt_stat.f_mntfromname);
1966 		*vpp = NULL;
1967 		return EINVAL;
1968 	}
1969 
1970 	error = 0;
1971 	hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1972 
1973 	while (pmp->inode_tid == 0) {
1974 		hammer2_xop_ipcluster_t *xop;
1975 		const hammer2_inode_meta_t *meta;
1976 
1977 		xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1978 		hammer2_xop_start(&xop->head, &hammer2_ipcluster_desc);
1979 		error = hammer2_xop_collect(&xop->head, 0);
1980 
1981 		if (error == 0) {
1982 			meta = &hammer2_xop_gdata(&xop->head)->ipdata.meta;
1983 			pmp->iroot->meta = *meta;
1984 			pmp->inode_tid = meta->pfs_inum + 1;
1985 			hammer2_xop_pdata(&xop->head);
1986 			/* meta invalid */
1987 
1988 			if (pmp->inode_tid < HAMMER2_INODE_START)
1989 				pmp->inode_tid = HAMMER2_INODE_START;
1990 			pmp->modify_tid =
1991 				xop->head.cluster.focus->bref.modify_tid + 1;
1992 #if 0
1993 			kprintf("PFS: Starting inode %jd\n",
1994 				(intmax_t)pmp->inode_tid);
1995 			kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1996 				pmp->inode_tid, pmp->modify_tid);
1997 #endif
1998 			wakeup(&pmp->iroot);
1999 
2000 			hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2001 
2002 			/*
2003 			 * Prime the mount info.
2004 			 */
2005 			hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
2006 			break;
2007 		}
2008 
2009 		/*
2010 		 * Loop, try again
2011 		 */
2012 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2013 		hammer2_inode_unlock(pmp->iroot);
2014 		error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
2015 		hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
2016 		if (error == EINTR)
2017 			break;
2018 	}
2019 
2020 	if (error) {
2021 		hammer2_inode_unlock(pmp->iroot);
2022 		*vpp = NULL;
2023 	} else {
2024 		vp = hammer2_igetv(pmp->iroot, &error);
2025 		hammer2_inode_unlock(pmp->iroot);
2026 		*vpp = vp;
2027 	}
2028 
2029 	return (error);
2030 }
2031 
2032 /*
2033  * Filesystem status
2034  *
2035  * XXX incorporate ipdata->meta.inode_quota and data_quota
2036  */
2037 static
2038 int
2039 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
2040 {
2041 	hammer2_pfs_t *pmp;
2042 	hammer2_dev_t *hmp;
2043 	hammer2_blockref_t bref;
2044 	struct statfs tmp;
2045 	int i;
2046 
2047 	/*
2048 	 * NOTE: iroot might not have validated the cluster yet.
2049 	 */
2050 	pmp = MPTOPMP(mp);
2051 
2052 	bzero(&tmp, sizeof(tmp));
2053 
2054 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2055 		hmp = pmp->pfs_hmps[i];
2056 		if (hmp == NULL)
2057 			continue;
2058 		if (pmp->iroot->cluster.array[i].chain)
2059 			bref = pmp->iroot->cluster.array[i].chain->bref;
2060 		else
2061 			bzero(&bref, sizeof(bref));
2062 
2063 		tmp.f_files = bref.embed.stats.inode_count;
2064 		tmp.f_ffree = 0;
2065 		tmp.f_blocks = hmp->voldata.allocator_size /
2066 			       mp->mnt_vstat.f_bsize;
2067 		tmp.f_bfree = hmp->voldata.allocator_free /
2068 			      mp->mnt_vstat.f_bsize;
2069 		tmp.f_bavail = tmp.f_bfree;
2070 
2071 		if (cred && cred->cr_uid != 0) {
2072 			uint64_t adj;
2073 
2074 			/* 5% */
2075 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2076 			tmp.f_blocks -= adj;
2077 			tmp.f_bfree -= adj;
2078 			tmp.f_bavail -= adj;
2079 		}
2080 
2081 		mp->mnt_stat.f_blocks = tmp.f_blocks;
2082 		mp->mnt_stat.f_bfree = tmp.f_bfree;
2083 		mp->mnt_stat.f_bavail = tmp.f_bavail;
2084 		mp->mnt_stat.f_files = tmp.f_files;
2085 		mp->mnt_stat.f_ffree = tmp.f_ffree;
2086 
2087 		*sbp = mp->mnt_stat;
2088 	}
2089 	return (0);
2090 }
2091 
2092 static
2093 int
2094 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
2095 {
2096 	hammer2_pfs_t *pmp;
2097 	hammer2_dev_t *hmp;
2098 	hammer2_blockref_t bref;
2099 	struct statvfs tmp;
2100 	int i;
2101 
2102 	/*
2103 	 * NOTE: iroot might not have validated the cluster yet.
2104 	 */
2105 	pmp = MPTOPMP(mp);
2106 	bzero(&tmp, sizeof(tmp));
2107 
2108 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2109 		hmp = pmp->pfs_hmps[i];
2110 		if (hmp == NULL)
2111 			continue;
2112 		if (pmp->iroot->cluster.array[i].chain)
2113 			bref = pmp->iroot->cluster.array[i].chain->bref;
2114 		else
2115 			bzero(&bref, sizeof(bref));
2116 
2117 		tmp.f_files = bref.embed.stats.inode_count;
2118 		tmp.f_ffree = 0;
2119 		tmp.f_blocks = hmp->voldata.allocator_size /
2120 			       mp->mnt_vstat.f_bsize;
2121 		tmp.f_bfree = hmp->voldata.allocator_free /
2122 			      mp->mnt_vstat.f_bsize;
2123 		tmp.f_bavail = tmp.f_bfree;
2124 
2125 		if (cred && cred->cr_uid != 0) {
2126 			uint64_t adj;
2127 
2128 			/* 5% */
2129 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2130 			tmp.f_blocks -= adj;
2131 			tmp.f_bfree -= adj;
2132 			tmp.f_bavail -= adj;
2133 		}
2134 
2135 		mp->mnt_vstat.f_blocks = tmp.f_blocks;
2136 		mp->mnt_vstat.f_bfree = tmp.f_bfree;
2137 		mp->mnt_vstat.f_bavail = tmp.f_bavail;
2138 		mp->mnt_vstat.f_files = tmp.f_files;
2139 		mp->mnt_vstat.f_ffree = tmp.f_ffree;
2140 
2141 		*sbp = mp->mnt_vstat;
2142 	}
2143 	return (0);
2144 }
2145 
2146 /*
2147  * Mount-time recovery (RW mounts)
2148  *
2149  * Updates to the free block table are allowed to lag flushes by one
2150  * transaction.  In case of a crash, then on a fresh mount we must do an
2151  * incremental scan of the last committed transaction id and make sure that
2152  * all related blocks have been marked allocated.
2153  */
2154 struct hammer2_recovery_elm {
2155 	TAILQ_ENTRY(hammer2_recovery_elm) entry;
2156 	hammer2_chain_t *chain;
2157 	hammer2_tid_t sync_tid;
2158 };
2159 
2160 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
2161 
2162 struct hammer2_recovery_info {
2163 	struct hammer2_recovery_list list;
2164 	hammer2_tid_t	mtid;
2165 	int	depth;
2166 };
2167 
2168 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
2169 			hammer2_chain_t *parent,
2170 			struct hammer2_recovery_info *info,
2171 			hammer2_tid_t sync_tid);
2172 
2173 #define HAMMER2_RECOVERY_MAXDEPTH	10
2174 
2175 static
2176 int
2177 hammer2_recovery(hammer2_dev_t *hmp)
2178 {
2179 	struct hammer2_recovery_info info;
2180 	struct hammer2_recovery_elm *elm;
2181 	hammer2_chain_t *parent;
2182 	hammer2_tid_t sync_tid;
2183 	hammer2_tid_t mirror_tid;
2184 	int error;
2185 
2186 	hammer2_trans_init(hmp->spmp, 0);
2187 
2188 	sync_tid = hmp->voldata.freemap_tid;
2189 	mirror_tid = hmp->voldata.mirror_tid;
2190 
2191 	kprintf("hammer2_mount: \"%s\": ", hmp->devrepname);
2192 	if (sync_tid >= mirror_tid) {
2193 		kprintf("no recovery needed\n");
2194 	} else {
2195 		kprintf("freemap recovery %016jx-%016jx\n",
2196 			sync_tid + 1, mirror_tid);
2197 	}
2198 
2199 	TAILQ_INIT(&info.list);
2200 	info.depth = 0;
2201 	parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
2202 	error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
2203 	hammer2_chain_lookup_done(parent);
2204 
2205 	while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
2206 		TAILQ_REMOVE(&info.list, elm, entry);
2207 		parent = elm->chain;
2208 		sync_tid = elm->sync_tid;
2209 		kfree(elm, M_HAMMER2);
2210 
2211 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2212 		error |= hammer2_recovery_scan(hmp, parent, &info,
2213 					      hmp->voldata.freemap_tid);
2214 		hammer2_chain_unlock(parent);
2215 		hammer2_chain_drop(parent);	/* drop elm->chain ref */
2216 	}
2217 
2218 	hammer2_trans_done(hmp->spmp, 0);
2219 
2220 	return error;
2221 }
2222 
2223 static
2224 int
2225 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
2226 		      struct hammer2_recovery_info *info,
2227 		      hammer2_tid_t sync_tid)
2228 {
2229 	const hammer2_inode_data_t *ripdata;
2230 	hammer2_chain_t *chain;
2231 	hammer2_blockref_t bref;
2232 	int tmp_error;
2233 	int rup_error;
2234 	int error;
2235 	int first;
2236 
2237 	/*
2238 	 * Adjust freemap to ensure that the block(s) are marked allocated.
2239 	 */
2240 	if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
2241 		hammer2_freemap_adjust(hmp, &parent->bref,
2242 				       HAMMER2_FREEMAP_DORECOVER);
2243 	}
2244 
2245 	/*
2246 	 * Check type for recursive scan
2247 	 */
2248 	switch(parent->bref.type) {
2249 	case HAMMER2_BREF_TYPE_VOLUME:
2250 		/* data already instantiated */
2251 		break;
2252 	case HAMMER2_BREF_TYPE_INODE:
2253 		/*
2254 		 * Must instantiate data for DIRECTDATA test and also
2255 		 * for recursion.
2256 		 */
2257 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2258 		ripdata = &parent->data->ipdata;
2259 		if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
2260 			/* not applicable to recovery scan */
2261 			hammer2_chain_unlock(parent);
2262 			return 0;
2263 		}
2264 		hammer2_chain_unlock(parent);
2265 		break;
2266 	case HAMMER2_BREF_TYPE_INDIRECT:
2267 		/*
2268 		 * Must instantiate data for recursion
2269 		 */
2270 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2271 		hammer2_chain_unlock(parent);
2272 		break;
2273 	case HAMMER2_BREF_TYPE_DIRENT:
2274 	case HAMMER2_BREF_TYPE_DATA:
2275 	case HAMMER2_BREF_TYPE_FREEMAP:
2276 	case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2277 	case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2278 		/* not applicable to recovery scan */
2279 		return 0;
2280 		break;
2281 	default:
2282 		return HAMMER2_ERROR_BADBREF;
2283 	}
2284 
2285 	/*
2286 	 * Defer operation if depth limit reached.
2287 	 */
2288 	if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
2289 		struct hammer2_recovery_elm *elm;
2290 
2291 		elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
2292 		elm->chain = parent;
2293 		elm->sync_tid = sync_tid;
2294 		hammer2_chain_ref(parent);
2295 		TAILQ_INSERT_TAIL(&info->list, elm, entry);
2296 		/* unlocked by caller */
2297 
2298 		return(0);
2299 	}
2300 
2301 
2302 	/*
2303 	 * Recursive scan of the last flushed transaction only.  We are
2304 	 * doing this without pmp assignments so don't leave the chains
2305 	 * hanging around after we are done with them.
2306 	 *
2307 	 * error	Cumulative error this level only
2308 	 * rup_error	Cumulative error for recursion
2309 	 * tmp_error	Specific non-cumulative recursion error
2310 	 */
2311 	chain = NULL;
2312 	first = 1;
2313 	rup_error = 0;
2314 	error = 0;
2315 
2316 	for (;;) {
2317 		error |= hammer2_chain_scan(parent, &chain, &bref,
2318 					    &first,
2319 					    HAMMER2_LOOKUP_NODATA);
2320 
2321 		/*
2322 		 * Problem during scan or EOF
2323 		 */
2324 		if (error)
2325 			break;
2326 
2327 		/*
2328 		 * If this is a leaf
2329 		 */
2330 		if (chain == NULL) {
2331 			if (bref.mirror_tid > sync_tid) {
2332 				hammer2_freemap_adjust(hmp, &bref,
2333 						     HAMMER2_FREEMAP_DORECOVER);
2334 			}
2335 			continue;
2336 		}
2337 
2338 		/*
2339 		 * This may or may not be a recursive node.
2340 		 */
2341 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
2342 		if (bref.mirror_tid > sync_tid) {
2343 			++info->depth;
2344 			tmp_error = hammer2_recovery_scan(hmp, chain,
2345 							   info, sync_tid);
2346 			--info->depth;
2347 		} else {
2348 			tmp_error = 0;
2349 		}
2350 
2351 		/*
2352 		 * Flush the recovery at the PFS boundary to stage it for
2353 		 * the final flush of the super-root topology.
2354 		 */
2355 		if (tmp_error == 0 &&
2356 		    (bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
2357 		    (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
2358 			hammer2_flush(chain, HAMMER2_FLUSH_TOP |
2359 					     HAMMER2_FLUSH_ALL);
2360 		}
2361 		rup_error |= tmp_error;
2362 	}
2363 	return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
2364 }
2365 
2366 /*
2367  * This fixes up an error introduced in earlier H2 implementations where
2368  * moving a PFS inode into an indirect block wound up causing the
2369  * HAMMER2_BREF_FLAG_PFSROOT flag in the bref to get cleared.
2370  */
2371 static
2372 int
2373 hammer2_fixup_pfses(hammer2_dev_t *hmp)
2374 {
2375 	const hammer2_inode_data_t *ripdata;
2376 	hammer2_chain_t *parent;
2377 	hammer2_chain_t *chain;
2378 	hammer2_key_t key_next;
2379 	hammer2_pfs_t *spmp;
2380 	int error;
2381 
2382 	error = 0;
2383 
2384 	/*
2385 	 * Lookup mount point under the media-localized super-root.
2386 	 *
2387 	 * cluster->pmp will incorrectly point to spmp and must be fixed
2388 	 * up later on.
2389 	 */
2390 	spmp = hmp->spmp;
2391 	hammer2_inode_lock(spmp->iroot, 0);
2392 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
2393 	chain = hammer2_chain_lookup(&parent, &key_next,
2394 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
2395 					 &error, 0);
2396 	while (chain) {
2397 		if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
2398 			continue;
2399 		if (chain->error) {
2400 			kprintf("I/O error scanning PFS labels\n");
2401 			error |= chain->error;
2402 		} else if ((chain->bref.flags &
2403 			    HAMMER2_BREF_FLAG_PFSROOT) == 0) {
2404 			int error2;
2405 
2406 			ripdata = &chain->data->ipdata;
2407 			hammer2_trans_init(hmp->spmp, 0);
2408 			error2 = hammer2_chain_modify(chain,
2409 						      chain->bref.modify_tid,
2410 						      0, 0);
2411 			if (error2 == 0) {
2412 				kprintf("hammer2: Correct mis-flagged PFS %s\n",
2413 					ripdata->filename);
2414 				chain->bref.flags |= HAMMER2_BREF_FLAG_PFSROOT;
2415 			} else {
2416 				error |= error2;
2417 			}
2418 			hammer2_flush(chain, HAMMER2_FLUSH_TOP |
2419 					     HAMMER2_FLUSH_ALL);
2420 			hammer2_trans_done(hmp->spmp, 0);
2421 		}
2422 		chain = hammer2_chain_next(&parent, chain, &key_next,
2423 					   key_next, HAMMER2_KEY_MAX,
2424 					   &error, 0);
2425 	}
2426 	if (parent) {
2427 		hammer2_chain_unlock(parent);
2428 		hammer2_chain_drop(parent);
2429 	}
2430 	hammer2_inode_unlock(spmp->iroot);
2431 
2432 	return error;
2433 }
2434 
2435 /*
2436  * Sync a mount point; this is called periodically on a per-mount basis from
2437  * the filesystem syncer, and whenever a user issues a sync.
2438  */
2439 int
2440 hammer2_vfs_sync(struct mount *mp, int waitfor)
2441 {
2442 	int error;
2443 
2444 	error = hammer2_vfs_sync_pmp(MPTOPMP(mp), waitfor);
2445 
2446 	return error;
2447 }
2448 
2449 /*
2450  * Because frontend operations lock vnodes before we get a chance to
2451  * lock the related inode, we can't just acquire a vnode lock without
2452  * risking a deadlock.  The frontend may be holding a vnode lock while
2453  * also blocked on our SYNCQ flag while trying to get the inode lock.
2454  *
2455  * To deal with this situation we can check the vnode lock situation
2456  * after locking the inode and perform a work-around.
2457  */
2458 int
2459 hammer2_vfs_sync_pmp(hammer2_pfs_t *pmp, int waitfor)
2460 {
2461 	struct mount *mp;
2462 	/*hammer2_xop_flush_t *xop;*/
2463 	hammer2_inode_t *ip;
2464 	hammer2_depend_t *depend;
2465 	hammer2_depend_t *depend_next;
2466 	struct vnode *vp;
2467 	uint32_t pass2;
2468 	int error;
2469 	int wakecount;
2470 	int dorestart;
2471 
2472 	mp = pmp->mp;
2473 
2474 	/*
2475 	 * Move all inodes on sideq to syncq.  This will clear sideq.
2476 	 * This should represent all flushable inodes.  These inodes
2477 	 * will already have refs due to being on syncq or sideq.  We
2478 	 * must do this all at once with the spinlock held to ensure that
2479 	 * all inode dependencies are part of the same flush.
2480 	 *
2481 	 * We should be able to do this asynchronously from frontend
2482 	 * operations because we will be locking the inodes later on
2483 	 * to actually flush them, and that will partition any frontend
2484 	 * op using the same inode.  Either it has already locked the
2485 	 * inode and we will block, or it has not yet locked the inode
2486 	 * and it will block until we are finished flushing that inode.
2487 	 *
2488 	 * When restarting, only move the inodes flagged as PASS2 from
2489 	 * SIDEQ to SYNCQ.  PASS2 propagation by inode_lock4() and
2490 	 * inode_depend() are atomic with the spin-lock.
2491 	 */
2492 	hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
2493 #ifdef HAMMER2_DEBUG_SYNC
2494 	kprintf("FILESYSTEM SYNC BOUNDARY\n");
2495 #endif
2496 	dorestart = 0;
2497 
2498 	/*
2499 	 * Move inodes from depq to syncq, releasing the related
2500 	 * depend structures.
2501 	 */
2502 restart:
2503 #ifdef HAMMER2_DEBUG_SYNC
2504 	kprintf("FILESYSTEM SYNC RESTART (%d)\n", dorestart);
2505 #endif
2506 	hammer2_trans_setflags(pmp, 0/*HAMMER2_TRANS_COPYQ*/);
2507 	hammer2_trans_clearflags(pmp, HAMMER2_TRANS_RESCAN);
2508 
2509 	/*
2510 	 * Move inodes from depq to syncq.  When restarting, only depq's
2511 	 * marked pass2 are moved.
2512 	 */
2513 	hammer2_spin_ex(&pmp->list_spin);
2514 	depend_next = TAILQ_FIRST(&pmp->depq);
2515 	wakecount = 0;
2516 
2517 	while ((depend = depend_next) != NULL) {
2518 		depend_next = TAILQ_NEXT(depend, entry);
2519 		if (dorestart && depend->pass2 == 0)
2520 			continue;
2521 		TAILQ_FOREACH(ip, &depend->sideq, entry) {
2522 			KKASSERT(ip->flags & HAMMER2_INODE_SIDEQ);
2523 			atomic_set_int(&ip->flags, HAMMER2_INODE_SYNCQ);
2524 			atomic_clear_int(&ip->flags, HAMMER2_INODE_SIDEQ);
2525 			ip->depend = NULL;
2526 		}
2527 
2528 		/*
2529 		 * NOTE: pmp->sideq_count includes both sideq and syncq
2530 		 */
2531 		TAILQ_CONCAT(&pmp->syncq, &depend->sideq, entry);
2532 
2533 		depend->count = 0;
2534 		depend->pass2 = 0;
2535 		TAILQ_REMOVE(&pmp->depq, depend, entry);
2536 	}
2537 
2538 	hammer2_spin_unex(&pmp->list_spin);
2539 	hammer2_trans_clearflags(pmp, /*HAMMER2_TRANS_COPYQ |*/
2540 				      HAMMER2_TRANS_WAITING);
2541 	dorestart = 0;
2542 
2543 	/*
2544 	 * sideq_count may have dropped enough to allow us to unstall
2545 	 * the frontend.
2546 	 */
2547 	hammer2_pfs_memory_wakeup(pmp, 0);
2548 
2549 	/*
2550 	 * Now run through all inodes on syncq.
2551 	 *
2552 	 * Flush transactions only interlock with other flush transactions.
2553 	 * Any conflicting frontend operations will block on the inode, but
2554 	 * may hold a vnode lock while doing so.
2555 	 */
2556 	hammer2_spin_ex(&pmp->list_spin);
2557 	while ((ip = TAILQ_FIRST(&pmp->syncq)) != NULL) {
2558 		/*
2559 		 * Remove the inode from the SYNCQ, transfer the syncq ref
2560 		 * to us.  We must clear SYNCQ to allow any potential
2561 		 * front-end deadlock to proceed.  We must set PASS2 so
2562 		 * the dependency code knows what to do.
2563 		 */
2564 		pass2 = ip->flags;
2565 		cpu_ccfence();
2566 		if (atomic_cmpset_int(&ip->flags,
2567 			      pass2,
2568 			      (pass2 & ~(HAMMER2_INODE_SYNCQ |
2569 					 HAMMER2_INODE_SYNCQ_WAKEUP)) |
2570 			      HAMMER2_INODE_SYNCQ_PASS2) == 0) {
2571 			continue;
2572 		}
2573 		TAILQ_REMOVE(&pmp->syncq, ip, entry);
2574 		--pmp->sideq_count;
2575 		hammer2_spin_unex(&pmp->list_spin);
2576 
2577 		/*
2578 		 * Tickle anyone waiting on ip->flags or the hysteresis
2579 		 * on the dirty inode count.
2580 		 */
2581 		if (pass2 & HAMMER2_INODE_SYNCQ_WAKEUP)
2582 			wakeup(&ip->flags);
2583 		if (++wakecount >= hammer2_limit_dirty_inodes / 20 + 1) {
2584 			wakecount = 0;
2585 			hammer2_pfs_memory_wakeup(pmp, 0);
2586 		}
2587 
2588 		/*
2589 		 * Relock the inode, and we inherit a ref from the above.
2590 		 * We will check for a race after we acquire the vnode.
2591 		 */
2592 		hammer2_mtx_ex(&ip->lock);
2593 
2594 		/*
2595 		 * We need the vp in order to vfsync() dirty buffers, so if
2596 		 * one isn't attached we can skip it.
2597 		 *
2598 		 * Ordering the inode lock and then the vnode lock has the
2599 		 * potential to deadlock.  If we had left SYNCQ set that could
2600 		 * also deadlock us against the frontend even if we don't hold
2601 		 * any locks, but the latter is not a problem now since we
2602 		 * cleared it.  igetv will temporarily release the inode lock
2603 		 * in a safe manner to work-around the deadlock.
2604 		 *
2605 		 * Unfortunately it is still possible to deadlock when the
2606 		 * frontend obtains multiple inode locks, because all the
2607 		 * related vnodes are already locked (nor can the vnode locks
2608 		 * be released and reacquired without messing up RECLAIM and
2609 		 * INACTIVE sequencing).
2610 		 *
2611 		 * The solution for now is to move the vp back onto SIDEQ
2612 		 * and set dorestart, which will restart the flush after we
2613 		 * exhaust the current SYNCQ.  Note that additional
2614 		 * dependencies may build up, so we definitely need to move
2615 		 * the whole SIDEQ back to SYNCQ when we restart.
2616 		 */
2617 		vp = ip->vp;
2618 		if (vp) {
2619 			if (vget(vp, LK_EXCLUSIVE|LK_NOWAIT)) {
2620 				/*
2621 				 * Failed to get the vnode, requeue the inode
2622 				 * (PASS2 is already set so it will be found
2623 				 * again on the restart).
2624 				 *
2625 				 * Then unlock, possibly sleep, and retry
2626 				 * later.  We sleep if PASS2 was *previously*
2627 				 * set, before we set it again above.
2628 				 */
2629 				vp = NULL;
2630 				dorestart = 1;
2631 #ifdef HAMMER2_DEBUG_SYNC
2632 				kprintf("inum %ld (sync delayed by vnode)\n",
2633 					(long)ip->meta.inum);
2634 #endif
2635 				hammer2_inode_delayed_sideq(ip);
2636 
2637 				hammer2_mtx_unlock(&ip->lock);
2638 				hammer2_inode_drop(ip);
2639 
2640 				if (pass2 & HAMMER2_INODE_SYNCQ_PASS2) {
2641 					tsleep(&dorestart, 0, "h2syndel", 2);
2642 				}
2643 				hammer2_spin_ex(&pmp->list_spin);
2644 				continue;
2645 			}
2646 		} else {
2647 			vp = NULL;
2648 		}
2649 
2650 		/*
2651 		 * If the inode wound up on a SIDEQ again it will already be
2652 		 * prepped for another PASS2.  In this situation if we flush
2653 		 * it now we will just wind up flushing it again in the same
2654 		 * syncer run, so we might as well not flush it now.
2655 		 */
2656 		if (ip->flags & HAMMER2_INODE_SIDEQ) {
2657 			hammer2_mtx_unlock(&ip->lock);
2658 			hammer2_inode_drop(ip);
2659 			if (vp)
2660 				vput(vp);
2661 			dorestart = 1;
2662 			hammer2_spin_ex(&pmp->list_spin);
2663 			continue;
2664 		}
2665 
2666 		/*
2667 		 * Ok we have the inode exclusively locked and if vp is
2668 		 * not NULL that will also be exclusively locked.  Do the
2669 		 * meat of the flush.
2670 		 *
2671 		 * vp token needed for v_rbdirty_tree check / vclrisdirty
2672 		 * sequencing.  Though we hold the vnode exclusively so
2673 		 * we shouldn't need to hold the token also in this case.
2674 		 */
2675 		if (vp) {
2676 			vfsync(vp, MNT_WAIT, 1, NULL, NULL);
2677 			bio_track_wait(&vp->v_track_write, 0, 0); /* XXX */
2678 		}
2679 
2680 		/*
2681 		 * If the inode has not yet been inserted into the tree
2682 		 * we must do so.  Then sync and flush it.  The flush should
2683 		 * update the parent.
2684 		 */
2685 		if (ip->flags & HAMMER2_INODE_DELETING) {
2686 #ifdef HAMMER2_DEBUG_SYNC
2687 			kprintf("inum %ld destroy\n", (long)ip->meta.inum);
2688 #endif
2689 			hammer2_inode_chain_des(ip);
2690 			atomic_add_long(&hammer2_iod_inode_deletes, 1);
2691 		} else if (ip->flags & HAMMER2_INODE_CREATING) {
2692 #ifdef HAMMER2_DEBUG_SYNC
2693 			kprintf("inum %ld insert\n", (long)ip->meta.inum);
2694 #endif
2695 			hammer2_inode_chain_ins(ip);
2696 			atomic_add_long(&hammer2_iod_inode_creates, 1);
2697 		}
2698 #ifdef HAMMER2_DEBUG_SYNC
2699 		kprintf("inum %ld chain-sync\n", (long)ip->meta.inum);
2700 #endif
2701 
2702 		/*
2703 		 * Because I kinda messed up the design and index the inodes
2704 		 * under the root inode, along side the directory entries,
2705 		 * we can't flush the inode index under the iroot until the
2706 		 * end.  If we do it now we might miss effects created by
2707 		 * other inodes on the SYNCQ.
2708 		 *
2709 		 * Do a normal (non-FSSYNC) flush instead, which allows the
2710 		 * vnode code to work the same.  We don't want to force iroot
2711 		 * back onto the SIDEQ, and we also don't want the flush code
2712 		 * to update pfs_iroot_blocksets until the final flush later.
2713 		 *
2714 		 * XXX at the moment this will likely result in a double-flush
2715 		 * of the iroot chain.
2716 		 */
2717 		hammer2_inode_chain_sync(ip);
2718 		if (ip == pmp->iroot) {
2719 			hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP);
2720 		} else {
2721 			hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP |
2722 						      HAMMER2_XOP_FSSYNC);
2723 		}
2724 		if (vp) {
2725 			lwkt_gettoken(&vp->v_token);
2726 			if ((ip->flags & (HAMMER2_INODE_MODIFIED |
2727 					  HAMMER2_INODE_RESIZED |
2728 					  HAMMER2_INODE_DIRTYDATA)) == 0 &&
2729 			    RB_EMPTY(&vp->v_rbdirty_tree) &&
2730 			    !bio_track_active(&vp->v_track_write)) {
2731 				vclrisdirty(vp);
2732 			} else {
2733 				hammer2_inode_delayed_sideq(ip);
2734 			}
2735 			lwkt_reltoken(&vp->v_token);
2736 			vput(vp);
2737 			vp = NULL;	/* safety */
2738 		}
2739 		atomic_clear_int(&ip->flags, HAMMER2_INODE_SYNCQ_PASS2);
2740 		hammer2_inode_unlock(ip);	/* unlock+drop */
2741 		/* ip pointer invalid */
2742 
2743 		/*
2744 		 * If the inode got dirted after we dropped our locks,
2745 		 * it will have already been moved back to the SIDEQ.
2746 		 */
2747 		hammer2_spin_ex(&pmp->list_spin);
2748 	}
2749 	hammer2_spin_unex(&pmp->list_spin);
2750 	hammer2_pfs_memory_wakeup(pmp, 0);
2751 
2752 	if (dorestart || (pmp->trans.flags & HAMMER2_TRANS_RESCAN)) {
2753 #ifdef HAMMER2_DEBUG_SYNC
2754 		kprintf("FILESYSTEM SYNC STAGE 1 RESTART\n");
2755 		/*tsleep(&dorestart, 0, "h2STG1-R", hz*20);*/
2756 #endif
2757 		dorestart = 1;
2758 		goto restart;
2759 	}
2760 #ifdef HAMMER2_DEBUG_SYNC
2761 	kprintf("FILESYSTEM SYNC STAGE 2 BEGIN\n");
2762 	/*tsleep(&dorestart, 0, "h2STG2", hz*20);*/
2763 #endif
2764 
2765 	/*
2766 	 * We have to flush the PFS root last, even if it does not appear to
2767 	 * be dirty, because all the inodes in the PFS are indexed under it.
2768 	 * The normal flushing of iroot above would only occur if directory
2769 	 * entries under the root were changed.
2770 	 *
2771 	 * Specifying VOLHDR will cause an additionl flush of hmp->spmp
2772 	 * for the media making up the cluster.
2773 	 */
2774 	if ((ip = pmp->iroot) != NULL) {
2775 		hammer2_inode_ref(ip);
2776 		hammer2_mtx_ex(&ip->lock);
2777 		hammer2_inode_chain_sync(ip);
2778 		hammer2_inode_chain_flush(ip, HAMMER2_XOP_INODE_STOP |
2779 					      HAMMER2_XOP_FSSYNC |
2780 					      HAMMER2_XOP_VOLHDR);
2781 		hammer2_inode_unlock(ip);	/* unlock+drop */
2782 	}
2783 #ifdef HAMMER2_DEBUG_SYNC
2784 	kprintf("FILESYSTEM SYNC STAGE 2 DONE\n");
2785 #endif
2786 
2787 	/*
2788 	 * device bioq sync
2789 	 */
2790 	hammer2_bioq_sync(pmp);
2791 
2792 #if 0
2793 	/*
2794 	 * Generally speaking we now want to flush the media topology from
2795 	 * the iroot through to the inodes.  The flush stops at any inode
2796 	 * boundary, which allows the frontend to continue running concurrent
2797 	 * modifying operations on inodes (including kernel flushes of
2798 	 * buffers) without interfering with the main sync.
2799 	 *
2800 	 * Use the XOP interface to concurrently flush all nodes to
2801 	 * synchronize the PFSROOT subtopology to the media.  A standard
2802 	 * end-of-scan ENOENT error indicates cluster sufficiency.
2803 	 *
2804 	 * Note that this flush will not be visible on crash recovery until
2805 	 * we flush the super-root topology in the next loop.
2806 	 *
2807 	 * XXX For now wait for all flushes to complete.
2808 	 */
2809 	if (mp && (ip = pmp->iroot) != NULL) {
2810 		/*
2811 		 * If unmounting try to flush everything including any
2812 		 * sub-trees under inodes, just in case there is dangling
2813 		 * modified data, as a safety.  Otherwise just flush up to
2814 		 * the inodes in this stage.
2815 		 */
2816 		kprintf("MP & IROOT\n");
2817 #ifdef HAMMER2_DEBUG_SYNC
2818 		kprintf("FILESYSTEM SYNC STAGE 3 IROOT BEGIN\n");
2819 #endif
2820 		if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
2821 			xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
2822 						    HAMMER2_XOP_VOLHDR |
2823 						    HAMMER2_XOP_FSSYNC |
2824 						    HAMMER2_XOP_INODE_STOP);
2825 		} else {
2826 			xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
2827 						    HAMMER2_XOP_INODE_STOP |
2828 						    HAMMER2_XOP_VOLHDR |
2829 						    HAMMER2_XOP_FSSYNC |
2830 						    HAMMER2_XOP_INODE_STOP);
2831 		}
2832 		hammer2_xop_start(&xop->head, &hammer2_inode_flush_desc);
2833 		error = hammer2_xop_collect(&xop->head,
2834 					    HAMMER2_XOP_COLLECT_WAITALL);
2835 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2836 #ifdef HAMMER2_DEBUG_SYNC
2837 		kprintf("FILESYSTEM SYNC STAGE 3 IROOT END\n");
2838 #endif
2839 		if (error == HAMMER2_ERROR_ENOENT)
2840 			error = 0;
2841 		else
2842 			error = hammer2_error_to_errno(error);
2843 	} else {
2844 		error = 0;
2845 	}
2846 #endif
2847 	error = 0;	/* XXX */
2848 	hammer2_trans_done(pmp, HAMMER2_TRANS_ISFLUSH);
2849 
2850 	return (error);
2851 }
2852 
2853 static
2854 int
2855 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2856 {
2857 	hammer2_inode_t *ip;
2858 
2859 	KKASSERT(MAXFIDSZ >= 16);
2860 	ip = VTOI(vp);
2861 	fhp->fid_len = offsetof(struct fid, fid_data[16]);
2862 	fhp->fid_ext = 0;
2863 	((hammer2_tid_t *)fhp->fid_data)[0] = ip->meta.inum;
2864 	((hammer2_tid_t *)fhp->fid_data)[1] = 0;
2865 
2866 	return 0;
2867 }
2868 
2869 static
2870 int
2871 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2872 	       struct fid *fhp, struct vnode **vpp)
2873 {
2874 	hammer2_pfs_t *pmp;
2875 	hammer2_tid_t inum;
2876 	int error;
2877 
2878 	pmp = MPTOPMP(mp);
2879 	inum = ((hammer2_tid_t *)fhp->fid_data)[0] & HAMMER2_DIRHASH_USERMSK;
2880 	if (vpp) {
2881 		if (inum == 1)
2882 			error = hammer2_vfs_root(mp, vpp);
2883 		else
2884 			error = hammer2_vfs_vget(mp, NULL, inum, vpp);
2885 	} else {
2886 		error = 0;
2887 	}
2888 	return error;
2889 }
2890 
2891 static
2892 int
2893 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2894 		 int *exflagsp, struct ucred **credanonp)
2895 {
2896 	hammer2_pfs_t *pmp;
2897 	struct netcred *np;
2898 	int error;
2899 
2900 	pmp = MPTOPMP(mp);
2901 	np = vfs_export_lookup(mp, &pmp->export, nam);
2902 	if (np) {
2903 		*exflagsp = np->netc_exflags;
2904 		*credanonp = &np->netc_anon;
2905 		error = 0;
2906 	} else {
2907 		error = EACCES;
2908 	}
2909 	return error;
2910 }
2911 
2912 /*
2913  * This handles hysteresis on regular file flushes.  Because the BIOs are
2914  * routed to a thread it is possible for an excessive number to build up
2915  * and cause long front-end stalls long before the runningbuffspace limit
2916  * is hit, so we implement hammer2_flush_pipe to control the
2917  * hysteresis.
2918  *
2919  * This is a particular problem when compression is used.
2920  */
2921 void
2922 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
2923 {
2924 	atomic_add_int(&pmp->count_lwinprog, 1);
2925 }
2926 
2927 void
2928 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
2929 {
2930 	int lwinprog;
2931 
2932 	lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
2933 	if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
2934 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
2935 		atomic_clear_int(&pmp->count_lwinprog,
2936 				 HAMMER2_LWINPROG_WAITING);
2937 		wakeup(&pmp->count_lwinprog);
2938 	}
2939 	if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
2940 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
2941 		atomic_clear_int(&pmp->count_lwinprog,
2942 				 HAMMER2_LWINPROG_WAITING0);
2943 		wakeup(&pmp->count_lwinprog);
2944 	}
2945 }
2946 
2947 void
2948 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
2949 {
2950 	int lwinprog;
2951 	int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
2952 				    HAMMER2_LWINPROG_WAITING0;
2953 
2954 	for (;;) {
2955 		lwinprog = pmp->count_lwinprog;
2956 		cpu_ccfence();
2957 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2958 			break;
2959 		tsleep_interlock(&pmp->count_lwinprog, 0);
2960 		atomic_set_int(&pmp->count_lwinprog, lwflag);
2961 		lwinprog = pmp->count_lwinprog;
2962 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2963 			break;
2964 		tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
2965 	}
2966 }
2967 
2968 /*
2969  * It is possible for an excessive number of dirty chains or dirty inodes
2970  * to build up.  When this occurs we start an asynchronous filesystem sync.
2971  * If the level continues to build up, we stall, waiting for it to drop,
2972  * with some hysteresis.
2973  *
2974  * This relies on the kernel calling hammer2_vfs_modifying() prior to
2975  * obtaining any vnode locks before making a modifying VOP call.
2976  */
2977 static int
2978 hammer2_vfs_modifying(struct mount *mp)
2979 {
2980 	if (mp->mnt_flag & MNT_RDONLY)
2981 		return EROFS;
2982 	hammer2_pfs_memory_wait(MPTOPMP(mp));
2983 
2984 	return 0;
2985 }
2986 
2987 /*
2988  * Initiate an asynchronous filesystem sync and, with hysteresis,
2989  * stall if the internal data structure count becomes too bloated.
2990  */
2991 void
2992 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
2993 {
2994 	uint32_t waiting;
2995 	int pcatch;
2996 	int error;
2997 
2998 	if (pmp == NULL || pmp->mp == NULL)
2999 		return;
3000 
3001 	for (;;) {
3002 		waiting = pmp->inmem_dirty_chains & HAMMER2_DIRTYCHAIN_MASK;
3003 		cpu_ccfence();
3004 
3005 		/*
3006 		 * Start the syncer running at 1/2 the limit
3007 		 */
3008 		if (waiting > hammer2_limit_dirty_chains / 2 ||
3009 		    pmp->sideq_count > hammer2_limit_dirty_inodes / 2) {
3010 			trigger_syncer(pmp->mp);
3011 		}
3012 
3013 		/*
3014 		 * Stall at the limit waiting for the counts to drop.
3015 		 * This code will typically be woken up once the count
3016 		 * drops below 3/4 the limit, or in one second.
3017 		 */
3018 		if (waiting < hammer2_limit_dirty_chains &&
3019 		    pmp->sideq_count < hammer2_limit_dirty_inodes) {
3020 			break;
3021 		}
3022 
3023 		pcatch = curthread->td_proc ? PCATCH : 0;
3024 
3025 		tsleep_interlock(&pmp->inmem_dirty_chains, pcatch);
3026 		atomic_set_int(&pmp->inmem_dirty_chains,
3027 			       HAMMER2_DIRTYCHAIN_WAITING);
3028 		if (waiting < hammer2_limit_dirty_chains &&
3029 		    pmp->sideq_count < hammer2_limit_dirty_inodes) {
3030 			break;
3031 		}
3032 		trigger_syncer(pmp->mp);
3033 		error = tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED | pcatch,
3034 			       "h2memw", hz);
3035 		if (error == ERESTART)
3036 			break;
3037 	}
3038 }
3039 
3040 /*
3041  * Wake up any stalled frontend ops waiting, with hysteresis, using
3042  * 2/3 of the limit.
3043  */
3044 void
3045 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp, int count)
3046 {
3047 	uint32_t waiting;
3048 
3049 	if (pmp) {
3050 		waiting = atomic_fetchadd_int(&pmp->inmem_dirty_chains, count);
3051 		/* don't need --waiting to test flag */
3052 
3053 		if ((waiting & HAMMER2_DIRTYCHAIN_WAITING) &&
3054 		    (pmp->inmem_dirty_chains & HAMMER2_DIRTYCHAIN_MASK) <=
3055 		    hammer2_limit_dirty_chains * 2 / 3 &&
3056 		    pmp->sideq_count <= hammer2_limit_dirty_inodes * 2 / 3) {
3057 			atomic_clear_int(&pmp->inmem_dirty_chains,
3058 					 HAMMER2_DIRTYCHAIN_WAITING);
3059 			wakeup(&pmp->inmem_dirty_chains);
3060 		}
3061 	}
3062 }
3063 
3064 void
3065 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
3066 {
3067 	if (pmp) {
3068 		atomic_add_int(&pmp->inmem_dirty_chains, 1);
3069 	}
3070 }
3071 
3072 /*
3073  * Volume header data locks
3074  */
3075 void
3076 hammer2_voldata_lock(hammer2_dev_t *hmp)
3077 {
3078 	lockmgr(&hmp->vollk, LK_EXCLUSIVE);
3079 }
3080 
3081 void
3082 hammer2_voldata_unlock(hammer2_dev_t *hmp)
3083 {
3084 	lockmgr(&hmp->vollk, LK_RELEASE);
3085 }
3086 
3087 /*
3088  * Caller indicates that the volume header is being modified.  Flag
3089  * the related chain and adjust its transaction id.
3090  *
3091  * The transaction id is set to voldata.mirror_tid + 1, similar to
3092  * what hammer2_chain_modify() does.  Be very careful here, volume
3093  * data can be updated independently of the rest of the filesystem.
3094  */
3095 void
3096 hammer2_voldata_modify(hammer2_dev_t *hmp)
3097 {
3098 	if ((hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) == 0) {
3099 		atomic_add_long(&hammer2_count_modified_chains, 1);
3100 		atomic_set_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
3101 		hammer2_pfs_memory_inc(hmp->vchain.pmp);
3102 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid + 1;
3103 	}
3104 }
3105 
3106 /*
3107  * Returns 0 if the filesystem has tons of free space
3108  * Returns 1 if the filesystem has less than 10% remaining
3109  * Returns 2 if the filesystem has less than 2%/5% (user/root) remaining.
3110  */
3111 int
3112 hammer2_vfs_enospace(hammer2_inode_t *ip, off_t bytes, struct ucred *cred)
3113 {
3114 	hammer2_pfs_t *pmp;
3115 	hammer2_dev_t *hmp;
3116 	hammer2_off_t free_reserved;
3117 	hammer2_off_t free_nominal;
3118 	int i;
3119 
3120 	pmp = ip->pmp;
3121 
3122 	if (pmp->free_ticks == 0 || pmp->free_ticks != ticks) {
3123 		free_reserved = HAMMER2_SEGSIZE;
3124 		free_nominal = 0x7FFFFFFFFFFFFFFFLLU;
3125 		for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
3126 			hmp = pmp->pfs_hmps[i];
3127 			if (hmp == NULL)
3128 				continue;
3129 			if (pmp->pfs_types[i] != HAMMER2_PFSTYPE_MASTER &&
3130 			    pmp->pfs_types[i] != HAMMER2_PFSTYPE_SOFT_MASTER)
3131 				continue;
3132 
3133 			if (free_nominal > hmp->voldata.allocator_free)
3134 				free_nominal = hmp->voldata.allocator_free;
3135 			if (free_reserved < hmp->free_reserved)
3136 				free_reserved = hmp->free_reserved;
3137 		}
3138 
3139 		/*
3140 		 * SMP races ok
3141 		 */
3142 		pmp->free_reserved = free_reserved;
3143 		pmp->free_nominal = free_nominal;
3144 		pmp->free_ticks = ticks;
3145 	} else {
3146 		free_reserved = pmp->free_reserved;
3147 		free_nominal = pmp->free_nominal;
3148 	}
3149 	if (cred && cred->cr_uid != 0) {
3150 		if ((int64_t)(free_nominal - bytes) <
3151 		    (int64_t)free_reserved) {
3152 			return 2;
3153 		}
3154 	} else {
3155 		if ((int64_t)(free_nominal - bytes) <
3156 		    (int64_t)free_reserved / 2) {
3157 			return 2;
3158 		}
3159 	}
3160 	if ((int64_t)(free_nominal - bytes) < (int64_t)free_reserved * 2)
3161 		return 1;
3162 	return 0;
3163 }
3164 
3165 /*
3166  * Debugging
3167  */
3168 void
3169 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int bi, int *countp,
3170 		   char pfx, u_int flags)
3171 {
3172 	hammer2_chain_t *scan;
3173 	hammer2_chain_t *parent;
3174 
3175 	--*countp;
3176 	if (*countp == 0) {
3177 		kprintf("%*.*s...\n", tab, tab, "");
3178 		return;
3179 	}
3180 	if (*countp < 0)
3181 		return;
3182 	kprintf("%*.*s%c-chain %p %s.%-3d %016jx %016jx/%-2d mir=%016jx\n",
3183 		tab, tab, "", pfx, chain,
3184 		hammer2_bref_type_str(chain->bref.type), bi,
3185 		chain->bref.data_off, chain->bref.key, chain->bref.keybits,
3186 		chain->bref.mirror_tid);
3187 
3188 	kprintf("%*.*s      [%08x] (%s) refs=%d",
3189 		tab, tab, "",
3190 		chain->flags,
3191 		((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
3192 		chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
3193 		chain->refs);
3194 
3195 	parent = chain->parent;
3196 	if (parent)
3197 		kprintf("\n%*.*s      p=%p [pflags %08x prefs %d]",
3198 			tab, tab, "",
3199 			parent, parent->flags, parent->refs);
3200 	if (RB_EMPTY(&chain->core.rbtree)) {
3201 		kprintf("\n");
3202 	} else {
3203 		int bi = 0;
3204 		kprintf(" {\n");
3205 		RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree) {
3206 			if ((scan->flags & flags) || flags == (u_int)-1) {
3207 				hammer2_dump_chain(scan, tab + 4, bi, countp,
3208 						   'a', flags);
3209 			}
3210 			bi++;
3211 		}
3212 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
3213 			kprintf("%*.*s}(%s)\n", tab, tab, "",
3214 				chain->data->ipdata.filename);
3215 		else
3216 			kprintf("%*.*s}\n", tab, tab, "");
3217 	}
3218 }
3219