xref: /dragonfly/sys/vfs/hammer2/hammer2_vfsops.c (revision 6e4c95df)
1 /*
2  * Copyright (c) 2011-2015 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  * by Daniel Flores (GSOC 2013 - mentored by Matthew Dillon, compression)
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/nlookup.h>
39 #include <sys/vnode.h>
40 #include <sys/mount.h>
41 #include <sys/fcntl.h>
42 #include <sys/buf.h>
43 #include <sys/uuid.h>
44 #include <sys/vfsops.h>
45 #include <sys/sysctl.h>
46 #include <sys/socket.h>
47 #include <sys/objcache.h>
48 
49 #include <sys/proc.h>
50 #include <sys/namei.h>
51 #include <sys/mountctl.h>
52 #include <sys/dirent.h>
53 #include <sys/uio.h>
54 
55 #include <sys/mutex.h>
56 #include <sys/mutex2.h>
57 
58 #include "hammer2.h"
59 #include "hammer2_disk.h"
60 #include "hammer2_mount.h"
61 #include "hammer2_lz4.h"
62 
63 #include "zlib/hammer2_zlib.h"
64 
65 #define REPORT_REFS_ERRORS 1	/* XXX remove me */
66 
67 MALLOC_DEFINE(M_OBJCACHE, "objcache", "Object Cache");
68 
69 struct hammer2_sync_info {
70 	int error;
71 	int waitfor;
72 };
73 
74 TAILQ_HEAD(hammer2_mntlist, hammer2_dev);
75 static struct hammer2_mntlist hammer2_mntlist;
76 
77 struct hammer2_pfslist hammer2_pfslist;
78 struct lock hammer2_mntlk;
79 
80 int hammer2_debug;
81 int hammer2_cluster_meta_read = 1;	/* physical read-ahead */
82 int hammer2_cluster_data_read = 4;	/* physical read-ahead */
83 int hammer2_cluster_write = 0;		/* bdwrite() so later inval works */
84 int hammer2_dedup_enable = 1;
85 int hammer2_always_compress = 0;	/* always try to compress */
86 int hammer2_inval_enable = 0;
87 int hammer2_flush_pipe = 100;
88 int hammer2_synchronous_flush = 1;
89 int hammer2_dio_count;
90 int hammer2_limit_dio = 256;
91 long hammer2_chain_allocs;
92 long hammer2_chain_frees;
93 long hammer2_limit_dirty_chains;
94 long hammer2_count_modified_chains;
95 long hammer2_iod_invals;
96 long hammer2_iod_file_read;
97 long hammer2_iod_meta_read;
98 long hammer2_iod_indr_read;
99 long hammer2_iod_fmap_read;
100 long hammer2_iod_volu_read;
101 long hammer2_iod_file_write;
102 long hammer2_iod_file_wembed;
103 long hammer2_iod_file_wzero;
104 long hammer2_iod_file_wdedup;
105 long hammer2_iod_meta_write;
106 long hammer2_iod_indr_write;
107 long hammer2_iod_fmap_write;
108 long hammer2_iod_volu_write;
109 
110 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
111 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
112 		"Buffer used for compression.");
113 
114 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
115 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
116 		"Buffer used for decompression.");
117 
118 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
119 
120 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
121 	   &hammer2_debug, 0, "");
122 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_meta_read, CTLFLAG_RW,
123 	   &hammer2_cluster_meta_read, 0, "");
124 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_data_read, CTLFLAG_RW,
125 	   &hammer2_cluster_data_read, 0, "");
126 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_write, CTLFLAG_RW,
127 	   &hammer2_cluster_write, 0, "");
128 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dedup_enable, CTLFLAG_RW,
129 	   &hammer2_dedup_enable, 0, "");
130 SYSCTL_INT(_vfs_hammer2, OID_AUTO, always_compress, CTLFLAG_RW,
131 	   &hammer2_always_compress, 0, "");
132 SYSCTL_INT(_vfs_hammer2, OID_AUTO, inval_enable, CTLFLAG_RW,
133 	   &hammer2_inval_enable, 0, "");
134 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
135 	   &hammer2_flush_pipe, 0, "");
136 SYSCTL_INT(_vfs_hammer2, OID_AUTO, synchronous_flush, CTLFLAG_RW,
137 	   &hammer2_synchronous_flush, 0, "");
138 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_allocs, CTLFLAG_RW,
139 	   &hammer2_chain_allocs, 0, "");
140 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, chain_frees, CTLFLAG_RW,
141 	   &hammer2_chain_frees, 0, "");
142 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
143 	   &hammer2_limit_dirty_chains, 0, "");
144 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, count_modified_chains, CTLFLAG_RW,
145 	   &hammer2_count_modified_chains, 0, "");
146 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
147 	   &hammer2_dio_count, 0, "");
148 SYSCTL_INT(_vfs_hammer2, OID_AUTO, limit_dio, CTLFLAG_RW,
149 	   &hammer2_limit_dio, 0, "");
150 
151 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_invals, CTLFLAG_RW,
152 	   &hammer2_iod_invals, 0, "");
153 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
154 	   &hammer2_iod_file_read, 0, "");
155 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
156 	   &hammer2_iod_meta_read, 0, "");
157 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
158 	   &hammer2_iod_indr_read, 0, "");
159 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
160 	   &hammer2_iod_fmap_read, 0, "");
161 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
162 	   &hammer2_iod_volu_read, 0, "");
163 
164 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
165 	   &hammer2_iod_file_write, 0, "");
166 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
167 	   &hammer2_iod_file_wembed, 0, "");
168 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
169 	   &hammer2_iod_file_wzero, 0, "");
170 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
171 	   &hammer2_iod_file_wdedup, 0, "");
172 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
173 	   &hammer2_iod_meta_write, 0, "");
174 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
175 	   &hammer2_iod_indr_write, 0, "");
176 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
177 	   &hammer2_iod_fmap_write, 0, "");
178 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
179 	   &hammer2_iod_volu_write, 0, "");
180 
181 long hammer2_check_icrc32;
182 long hammer2_check_xxhash64;
183 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_icrc32, CTLFLAG_RW,
184 	   &hammer2_check_icrc32, 0, "");
185 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, check_xxhash64, CTLFLAG_RW,
186 	   &hammer2_check_xxhash64, 0, "");
187 
188 static int hammer2_vfs_init(struct vfsconf *conf);
189 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
190 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
191 				struct ucred *cred);
192 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
193 				struct vnode *, struct ucred *);
194 static int hammer2_recovery(hammer2_dev_t *hmp);
195 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
196 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
197 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
198 				struct ucred *cred);
199 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
200 				struct ucred *cred);
201 static int hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
202 				struct fid *fhp, struct vnode **vpp);
203 static int hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp);
204 static int hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
205 				int *exflagsp, struct ucred **credanonp);
206 
207 static int hammer2_install_volume_header(hammer2_dev_t *hmp);
208 static int hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
209 
210 static void hammer2_update_pmps(hammer2_dev_t *hmp);
211 
212 static void hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp);
213 static void hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp,
214 				hammer2_dev_t *hmp);
215 
216 /*
217  * HAMMER2 vfs operations.
218  */
219 static struct vfsops hammer2_vfsops = {
220 	.vfs_init	= hammer2_vfs_init,
221 	.vfs_uninit	= hammer2_vfs_uninit,
222 	.vfs_sync	= hammer2_vfs_sync,
223 	.vfs_mount	= hammer2_vfs_mount,
224 	.vfs_unmount	= hammer2_vfs_unmount,
225 	.vfs_root 	= hammer2_vfs_root,
226 	.vfs_statfs	= hammer2_vfs_statfs,
227 	.vfs_statvfs	= hammer2_vfs_statvfs,
228 	.vfs_vget	= hammer2_vfs_vget,
229 	.vfs_vptofh	= hammer2_vfs_vptofh,
230 	.vfs_fhtovp	= hammer2_vfs_fhtovp,
231 	.vfs_checkexp	= hammer2_vfs_checkexp
232 };
233 
234 MALLOC_DEFINE(M_HAMMER2, "HAMMER2-mount", "");
235 
236 VFS_SET(hammer2_vfsops, hammer2, VFCF_MPSAFE);
237 MODULE_VERSION(hammer2, 1);
238 
239 static
240 int
241 hammer2_vfs_init(struct vfsconf *conf)
242 {
243 	static struct objcache_malloc_args margs_read;
244 	static struct objcache_malloc_args margs_write;
245 	static struct objcache_malloc_args margs_vop;
246 
247 	int error;
248 
249 	error = 0;
250 
251 	/*
252 	 * A large DIO cache is needed to retain dedup enablement masks.
253 	 * The bulkfree code clears related masks as part of the disk block
254 	 * recycling algorithm, preventing it from being used for a later
255 	 * dedup.
256 	 *
257 	 * NOTE: A large buffer cache can actually interfere with dedup
258 	 *	 operation because we dedup based on media physical buffers
259 	 *	 and not logical buffers.  Try to make the DIO chace large
260 	 *	 enough to avoid this problem, but also cap it.
261 	 */
262 	hammer2_limit_dio = nbuf * 2;
263 	if (hammer2_limit_dio > 100000)
264 		hammer2_limit_dio = 100000;
265 
266 	if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
267 		error = EINVAL;
268 	if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
269 		error = EINVAL;
270 	if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
271 		error = EINVAL;
272 
273 	if (error)
274 		kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
275 
276 	margs_read.objsize = 65536;
277 	margs_read.mtype = M_HAMMER2_DEBUFFER;
278 
279 	margs_write.objsize = 32768;
280 	margs_write.mtype = M_HAMMER2_CBUFFER;
281 
282 	margs_vop.objsize = sizeof(hammer2_xop_t);
283 	margs_vop.mtype = M_HAMMER2;
284 
285 	/*
286 	 * Note thaht for the XOPS cache we want backing store allocations
287 	 * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
288 	 * confusion), so use the backing store function that does it.  This
289 	 * means that initial XOPS objects are zerod but REUSED objects are
290 	 * not.  So we are responsible for cleaning the object up sufficiently
291 	 * for our needs before objcache_put()ing it back (typically just the
292 	 * FIFO indices).
293 	 */
294 	cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
295 				0, 1, NULL, NULL, NULL,
296 				objcache_malloc_alloc,
297 				objcache_malloc_free,
298 				&margs_read);
299 	cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
300 				0, 1, NULL, NULL, NULL,
301 				objcache_malloc_alloc,
302 				objcache_malloc_free,
303 				&margs_write);
304 	cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
305 				0, 1, NULL, NULL, NULL,
306 				objcache_malloc_alloc_zero,
307 				objcache_malloc_free,
308 				&margs_vop);
309 
310 
311 	lockinit(&hammer2_mntlk, "mntlk", 0, 0);
312 	TAILQ_INIT(&hammer2_mntlist);
313 	TAILQ_INIT(&hammer2_pfslist);
314 
315 	hammer2_limit_dirty_chains = maxvnodes / 10;
316 	if (hammer2_limit_dirty_chains > HAMMER2_LIMIT_DIRTY_CHAINS)
317 		hammer2_limit_dirty_chains = HAMMER2_LIMIT_DIRTY_CHAINS;
318 
319 	return (error);
320 }
321 
322 static
323 int
324 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
325 {
326 	objcache_destroy(cache_buffer_read);
327 	objcache_destroy(cache_buffer_write);
328 	objcache_destroy(cache_xops);
329 	return 0;
330 }
331 
332 /*
333  * Core PFS allocator.  Used to allocate or reference the pmp structure
334  * for PFS cluster mounts and the spmp structure for media (hmp) structures.
335  * The pmp can be passed in or loaded by this function using the chain and
336  * inode data.
337  *
338  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
339  * transactions.  Note that synchronization does not use this field.
340  * (typically frontend operations and synchronization cannot run on the
341  * same PFS node at the same time).
342  *
343  * XXX check locking
344  */
345 hammer2_pfs_t *
346 hammer2_pfsalloc(hammer2_chain_t *chain,
347 		 const hammer2_inode_data_t *ripdata,
348 		 hammer2_tid_t modify_tid, hammer2_dev_t *force_local)
349 {
350 	hammer2_pfs_t *pmp;
351 	hammer2_inode_t *iroot;
352 	int count;
353 	int i;
354 	int j;
355 
356 	pmp = NULL;
357 
358 	/*
359 	 * Locate or create the PFS based on the cluster id.  If ripdata
360 	 * is NULL this is a spmp which is unique and is always allocated.
361 	 *
362 	 * If the device is mounted in local mode all PFSs are considered
363 	 * independent and not part of any cluster (for debugging only).
364 	 */
365 	if (ripdata) {
366 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
367 			if (force_local != pmp->force_local)
368 				continue;
369 			if (force_local == NULL &&
370 			    bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
371 				 sizeof(pmp->pfs_clid)) == 0) {
372 					break;
373 			} else if (force_local && pmp->pfs_names[0] &&
374 			    strcmp(pmp->pfs_names[0], ripdata->filename) == 0) {
375 					break;
376 			}
377 		}
378 	}
379 
380 	if (pmp == NULL) {
381 		pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
382 		pmp->force_local = force_local;
383 		hammer2_trans_manage_init(pmp);
384 		kmalloc_create(&pmp->minode, "HAMMER2-inodes");
385 		kmalloc_create(&pmp->mmsg, "HAMMER2-pfsmsg");
386 		lockinit(&pmp->lock, "pfslk", 0, 0);
387 		lockinit(&pmp->lock_nlink, "h2nlink", 0, 0);
388 		spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
389 		spin_init(&pmp->xop_spin, "h2xop");
390 		spin_init(&pmp->lru_spin, "h2lru");
391 		RB_INIT(&pmp->inum_tree);
392 		TAILQ_INIT(&pmp->sideq);
393 		TAILQ_INIT(&pmp->lru_list);
394 		spin_init(&pmp->list_spin, "hm2pfsalloc_list");
395 
396 		/*
397 		 * Distribute backend operations to threads
398 		 */
399 		for (i = 0; i < HAMMER2_XOPGROUPS; ++i)
400 			hammer2_xop_group_init(pmp, &pmp->xop_groups[i]);
401 
402 		/*
403 		 * Save the last media transaction id for the flusher.  Set
404 		 * initial
405 		 */
406 		if (ripdata)
407 			pmp->pfs_clid = ripdata->meta.pfs_clid;
408 		TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
409 
410 		/*
411 		 * The synchronization thread may start too early, make
412 		 * sure it stays frozen until we are ready to let it go.
413 		 * XXX
414 		 */
415 		/*
416 		pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
417 					 HAMMER2_THREAD_REMASTER;
418 		*/
419 	}
420 
421 	/*
422 	 * Create the PFS's root inode and any missing XOP helper threads.
423 	 */
424 	if ((iroot = pmp->iroot) == NULL) {
425 		iroot = hammer2_inode_get(pmp, NULL, NULL, -1);
426 		if (ripdata)
427 			iroot->meta = ripdata->meta;
428 		pmp->iroot = iroot;
429 		hammer2_inode_ref(iroot);
430 		hammer2_inode_unlock(iroot);
431 	}
432 
433 	/*
434 	 * Stop here if no chain is passed in.
435 	 */
436 	if (chain == NULL)
437 		goto done;
438 
439 	/*
440 	 * When a chain is passed in we must add it to the PFS's root
441 	 * inode, update pmp->pfs_types[], and update the syncronization
442 	 * threads.
443 	 *
444 	 * When forcing local mode, mark the PFS as a MASTER regardless.
445 	 *
446 	 * At the moment empty spots can develop due to removals or failures.
447 	 * Ultimately we want to re-fill these spots but doing so might
448 	 * confused running code. XXX
449 	 */
450 	hammer2_inode_ref(iroot);
451 	hammer2_mtx_ex(&iroot->lock);
452 	j = iroot->cluster.nchains;
453 
454 	kprintf("add PFS to pmp %p[%d]\n", pmp, j);
455 
456 	if (j == HAMMER2_MAXCLUSTER) {
457 		kprintf("hammer2_mount: cluster full!\n");
458 		/* XXX fatal error? */
459 	} else {
460 		KKASSERT(chain->pmp == NULL);
461 		chain->pmp = pmp;
462 		hammer2_chain_ref(chain);
463 		iroot->cluster.array[j].chain = chain;
464 		if (force_local)
465 			pmp->pfs_types[j] = HAMMER2_PFSTYPE_MASTER;
466 		else
467 			pmp->pfs_types[j] = ripdata->meta.pfs_type;
468 		pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
469 		pmp->pfs_hmps[j] = chain->hmp;
470 
471 		/*
472 		 * If the PFS is already mounted we must account
473 		 * for the mount_count here.
474 		 */
475 		if (pmp->mp)
476 			++chain->hmp->mount_count;
477 
478 		/*
479 		 * May have to fixup dirty chain tracking.  Previous
480 		 * pmp was NULL so nothing to undo.
481 		 */
482 		if (chain->flags & HAMMER2_CHAIN_MODIFIED)
483 			hammer2_pfs_memory_inc(pmp);
484 		++j;
485 	}
486 	iroot->cluster.nchains = j;
487 
488 	/*
489 	 * Update nmasters from any PFS inode which is part of the cluster.
490 	 * It is possible that this will result in a value which is too
491 	 * high.  MASTER PFSs are authoritative for pfs_nmasters and will
492 	 * override this value later on.
493 	 *
494 	 * (This informs us of masters that might not currently be
495 	 *  discoverable by this mount).
496 	 */
497 	if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
498 		pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
499 	}
500 
501 	/*
502 	 * Count visible masters.  Masters are usually added with
503 	 * ripdata->meta.pfs_nmasters set to 1.  This detects when there
504 	 * are more (XXX and must update the master inodes).
505 	 */
506 	count = 0;
507 	for (i = 0; i < iroot->cluster.nchains; ++i) {
508 		if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
509 			++count;
510 	}
511 	if (pmp->pfs_nmasters < count)
512 		pmp->pfs_nmasters = count;
513 
514 	/*
515 	 * Create missing synchronization and support threads.
516 	 *
517 	 * Single-node masters (including snapshots) have nothing to
518 	 * synchronize and do not require this thread.
519 	 *
520 	 * Multi-node masters or any number of soft masters, slaves, copy,
521 	 * or other PFS types need the thread.
522 	 *
523 	 * Each thread is responsible for its particular cluster index.
524 	 * We use independent threads so stalls or mismatches related to
525 	 * any given target do not affect other targets.
526 	 */
527 	for (i = 0; i < iroot->cluster.nchains; ++i) {
528 		/*
529 		 * Single-node masters (including snapshots) have nothing
530 		 * to synchronize and will make direct xops support calls,
531 		 * thus they do not require this thread.
532 		 *
533 		 * Note that there can be thousands of snapshots.  We do not
534 		 * want to create thousands of threads.
535 		 */
536 		if (pmp->pfs_nmasters <= 1 &&
537 		    pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
538 			continue;
539 		}
540 
541 		/*
542 		 * Sync support thread
543 		 */
544 		if (pmp->sync_thrs[i].td == NULL) {
545 			hammer2_thr_create(&pmp->sync_thrs[i], pmp, NULL,
546 					   "h2nod", i, -1,
547 					   hammer2_primary_sync_thread);
548 		}
549 	}
550 
551 	/*
552 	 * Create missing Xop threads
553 	 *
554 	 * NOTE: We create helper threads for all mounted PFSs or any
555 	 *	 PFSs with 2+ nodes (so the sync thread can update them,
556 	 *	 even if not mounted).
557 	 */
558 	if (pmp->mp || iroot->cluster.nchains >= 2)
559 		hammer2_xop_helper_create(pmp);
560 
561 	hammer2_mtx_unlock(&iroot->lock);
562 	hammer2_inode_drop(iroot);
563 done:
564 	return pmp;
565 }
566 
567 /*
568  * Deallocate an element of a probed PFS.  If destroying and this is a
569  * MASTER, adjust nmasters.
570  *
571  * This function does not physically destroy the PFS element in its device
572  * under the super-root  (see hammer2_ioctl_pfs_delete()).
573  */
574 void
575 hammer2_pfsdealloc(hammer2_pfs_t *pmp, int clindex, int destroying)
576 {
577 	hammer2_inode_t *iroot;
578 	hammer2_chain_t *chain;
579 	int j;
580 
581 	/*
582 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
583 	 * by the flush code.
584 	 */
585 	iroot = pmp->iroot;
586 	if (iroot) {
587 		/*
588 		 * Stop synchronizing
589 		 *
590 		 * XXX flush after acquiring the iroot lock.
591 		 * XXX clean out the cluster index from all inode structures.
592 		 */
593 		hammer2_thr_delete(&pmp->sync_thrs[clindex]);
594 
595 		/*
596 		 * Remove the cluster index from the group.  If destroying
597 		 * the PFS and this is a master, adjust pfs_nmasters.
598 		 */
599 		hammer2_mtx_ex(&iroot->lock);
600 		chain = iroot->cluster.array[clindex].chain;
601 		iroot->cluster.array[clindex].chain = NULL;
602 
603 		switch(pmp->pfs_types[clindex]) {
604 		case HAMMER2_PFSTYPE_MASTER:
605 			if (destroying && pmp->pfs_nmasters > 0)
606 				--pmp->pfs_nmasters;
607 			/* XXX adjust ripdata->meta.pfs_nmasters */
608 			break;
609 		default:
610 			break;
611 		}
612 		pmp->pfs_types[clindex] = HAMMER2_PFSTYPE_NONE;
613 
614 		hammer2_mtx_unlock(&iroot->lock);
615 
616 		/*
617 		 * Release the chain.
618 		 */
619 		if (chain) {
620 			atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
621 			hammer2_chain_drop(chain);
622 		}
623 
624 		/*
625 		 * Terminate all XOP threads for the cluster index.
626 		 */
627 		for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
628 			hammer2_thr_delete(&pmp->xop_groups[j].thrs[clindex]);
629 	}
630 }
631 
632 /*
633  * Destroy a PFS, typically only occurs after the last mount on a device
634  * has gone away.
635  */
636 static void
637 hammer2_pfsfree(hammer2_pfs_t *pmp)
638 {
639 	hammer2_inode_t *iroot;
640 	hammer2_chain_t *chain;
641 	int i;
642 	int j;
643 
644 	/*
645 	 * Cleanup our reference on iroot.  iroot is (should) not be needed
646 	 * by the flush code.
647 	 */
648 	TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
649 
650 	iroot = pmp->iroot;
651 	if (iroot) {
652 		for (i = 0; i < iroot->cluster.nchains; ++i) {
653 			hammer2_thr_delete(&pmp->sync_thrs[i]);
654 			for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
655 				hammer2_thr_delete(&pmp->xop_groups[j].thrs[i]);
656 		}
657 #if REPORT_REFS_ERRORS
658 		if (pmp->iroot->refs != 1)
659 			kprintf("PMP->IROOT %p REFS WRONG %d\n",
660 				pmp->iroot, pmp->iroot->refs);
661 #else
662 		KKASSERT(pmp->iroot->refs == 1);
663 #endif
664 		/* ref for pmp->iroot */
665 		hammer2_inode_drop(pmp->iroot);
666 		pmp->iroot = NULL;
667 	}
668 
669 	/*
670 	 * Cleanup chains remaining on LRU list.
671 	 */
672 	kprintf("pfsfree: %p lrucount=%d\n", pmp, pmp->lru_count);
673 	while ((chain = TAILQ_FIRST(&pmp->lru_list)) != NULL) {
674 		hammer2_chain_ref(chain);
675 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
676 		hammer2_chain_drop(chain);
677 	}
678 
679 	/*
680 	 * Free remaining pmp resources
681 	 */
682 	kmalloc_destroy(&pmp->mmsg);
683 	kmalloc_destroy(&pmp->minode);
684 
685 	kfree(pmp, M_HAMMER2);
686 }
687 
688 /*
689  * Remove all references to hmp from the pfs list.  Any PFS which becomes
690  * empty is terminated and freed.
691  *
692  * XXX inefficient.
693  */
694 static void
695 hammer2_pfsfree_scan(hammer2_dev_t *hmp)
696 {
697 	hammer2_pfs_t *pmp;
698 	hammer2_inode_t *iroot;
699 	hammer2_chain_t *rchain;
700 	int didfreeze;
701 	int i;
702 	int j;
703 
704 again:
705 	TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
706 		if ((iroot = pmp->iroot) == NULL)
707 			continue;
708 		if (hmp->spmp == pmp) {
709 			kprintf("unmount hmp %p remove spmp %p\n",
710 				hmp, pmp);
711 			hmp->spmp = NULL;
712 		}
713 
714 		/*
715 		 * Determine if this PFS is affected.  If it is we must
716 		 * freeze all management threads and lock its iroot.
717 		 *
718 		 * Freezing a management thread forces it idle, operations
719 		 * in-progress will be aborted and it will have to start
720 		 * over again when unfrozen, or exit if told to exit.
721 		 */
722 		for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
723 			if (pmp->pfs_hmps[i] == hmp)
724 				break;
725 		}
726 		if (i != HAMMER2_MAXCLUSTER) {
727 			/*
728 			 * Make sure all synchronization threads are locked
729 			 * down.
730 			 */
731 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
732 				if (pmp->pfs_hmps[i] == NULL)
733 					continue;
734 				hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
735 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
736 					hammer2_thr_freeze_async(
737 						&pmp->xop_groups[j].thrs[i]);
738 				}
739 			}
740 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
741 				if (pmp->pfs_hmps[i] == NULL)
742 					continue;
743 				hammer2_thr_freeze(&pmp->sync_thrs[i]);
744 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
745 					hammer2_thr_freeze(
746 						&pmp->xop_groups[j].thrs[i]);
747 				}
748 			}
749 
750 			/*
751 			 * Lock the inode and clean out matching chains.
752 			 * Note that we cannot use hammer2_inode_lock_*()
753 			 * here because that would attempt to validate the
754 			 * cluster that we are in the middle of ripping
755 			 * apart.
756 			 *
757 			 * WARNING! We are working directly on the inodes
758 			 *	    embedded cluster.
759 			 */
760 			hammer2_mtx_ex(&iroot->lock);
761 
762 			/*
763 			 * Remove the chain from matching elements of the PFS.
764 			 */
765 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
766 				if (pmp->pfs_hmps[i] != hmp)
767 					continue;
768 				hammer2_thr_delete(&pmp->sync_thrs[i]);
769 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
770 					hammer2_thr_delete(
771 						&pmp->xop_groups[j].thrs[i]);
772 				}
773 				rchain = iroot->cluster.array[i].chain;
774 				iroot->cluster.array[i].chain = NULL;
775 				pmp->pfs_types[i] = 0;
776 				if (pmp->pfs_names[i]) {
777 					kfree(pmp->pfs_names[i], M_HAMMER2);
778 					pmp->pfs_names[i] = NULL;
779 				}
780 				if (rchain) {
781 					hammer2_chain_drop(rchain);
782 					/* focus hint */
783 					if (iroot->cluster.focus == rchain)
784 						iroot->cluster.focus = NULL;
785 				}
786 				pmp->pfs_hmps[i] = NULL;
787 			}
788 			hammer2_mtx_unlock(&iroot->lock);
789 			didfreeze = 1;	/* remaster, unfreeze down below */
790 		} else {
791 			didfreeze = 0;
792 		}
793 
794 		/*
795 		 * Cleanup trailing chains.  Gaps may remain.
796 		 */
797 		for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
798 			if (pmp->pfs_hmps[i])
799 				break;
800 		}
801 		iroot->cluster.nchains = i + 1;
802 
803 		/*
804 		 * If the PMP has no elements remaining we can destroy it.
805 		 * (this will transition management threads from frozen->exit).
806 		 */
807 		if (iroot->cluster.nchains == 0) {
808 			kprintf("unmount hmp %p last ref to PMP=%p\n",
809 				hmp, pmp);
810 			hammer2_pfsfree(pmp);
811 			goto again;
812 		}
813 
814 		/*
815 		 * If elements still remain we need to set the REMASTER
816 		 * flag and unfreeze it.
817 		 */
818 		if (didfreeze) {
819 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
820 				if (pmp->pfs_hmps[i] == NULL)
821 					continue;
822 				hammer2_thr_remaster(&pmp->sync_thrs[i]);
823 				hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
824 				for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
825 					hammer2_thr_remaster(
826 						&pmp->xop_groups[j].thrs[i]);
827 					hammer2_thr_unfreeze(
828 						&pmp->xop_groups[j].thrs[i]);
829 				}
830 			}
831 		}
832 	}
833 }
834 
835 /*
836  * Mount or remount HAMMER2 fileystem from physical media
837  *
838  *	mountroot
839  *		mp		mount point structure
840  *		path		NULL
841  *		data		<unused>
842  *		cred		<unused>
843  *
844  *	mount
845  *		mp		mount point structure
846  *		path		path to mount point
847  *		data		pointer to argument structure in user space
848  *			volume	volume path (device@LABEL form)
849  *			hflags	user mount flags
850  *		cred		user credentials
851  *
852  * RETURNS:	0	Success
853  *		!0	error number
854  */
855 static
856 int
857 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
858 		  struct ucred *cred)
859 {
860 	struct hammer2_mount_info info;
861 	hammer2_pfs_t *pmp;
862 	hammer2_pfs_t *spmp;
863 	hammer2_dev_t *hmp;
864 	hammer2_dev_t *force_local;
865 	hammer2_key_t key_next;
866 	hammer2_key_t key_dummy;
867 	hammer2_key_t lhc;
868 	struct vnode *devvp;
869 	struct nlookupdata nd;
870 	hammer2_chain_t *parent;
871 	hammer2_chain_t *chain;
872 	hammer2_cluster_t *cluster;
873 	const hammer2_inode_data_t *ripdata;
874 	hammer2_blockref_t bref;
875 	struct file *fp;
876 	char devstr[MNAMELEN];
877 	size_t size;
878 	size_t done;
879 	char *dev;
880 	char *label;
881 	int ronly = 1;
882 	int error;
883 	int i;
884 
885 	hmp = NULL;
886 	pmp = NULL;
887 	dev = NULL;
888 	label = NULL;
889 	devvp = NULL;
890 
891 	kprintf("hammer2_mount\n");
892 
893 	if (path == NULL) {
894 		/*
895 		 * Root mount
896 		 */
897 		bzero(&info, sizeof(info));
898 		info.cluster_fd = -1;
899 		ksnprintf(devstr, sizeof(devstr), "%s",
900 			  mp->mnt_stat.f_mntfromname);
901 		kprintf("hammer2_mount: root '%s'\n", devstr);
902 	} else {
903 		/*
904 		 * Non-root mount or updating a mount
905 		 */
906 		error = copyin(data, &info, sizeof(info));
907 		if (error)
908 			return (error);
909 
910 		error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
911 		if (error)
912 			return (error);
913 	}
914 
915 	/*
916 	 * Extract device and label, automatically mount @BOOT, @ROOT, or @DATA
917 	 * if no label specified, based on the partition id.  Error out if no
918 	 * partition id.  This is strictly a convenience to match the
919 	 * default label created by newfs_hammer2, our preference is
920 	 * that a label always be specified.
921 	 */
922 	dev = devstr;
923 	label = strchr(devstr, '@');
924 	if (label && ((label + 1) - dev) > done)
925 		return (EINVAL);
926 	if (label && label == devstr)
927 		return (EINVAL);
928 	if (label == NULL || label[1] == 0) {
929 		char slice;
930 
931 		if (label == NULL)
932 			label = devstr + strlen(devstr);
933 		slice = label[-1];
934 		switch(slice) {
935 		case 'a':
936 			label = "BOOT";
937 			break;
938 		case 'd':
939 			label = "ROOT";
940 			break;
941 		default:
942 			label = "DATA";
943 			break;
944 		}
945 	} else {
946 		*label = '\0';
947 		label++;
948 	}
949 
950 	kprintf("hammer2_mount: dev=\"%s\" label=\"%s\" rdonly=%d\n",
951 		dev, label, (mp->mnt_flag & MNT_RDONLY));
952 
953 	if (mp->mnt_flag & MNT_UPDATE) {
954 		/*
955 		 * Update mount.  Note that pmp->iroot->cluster is
956 		 * an inode-embedded cluster and thus cannot be
957 		 * directly locked.
958 		 *
959 		 * XXX HAMMER2 needs to implement NFS export via
960 		 *     mountctl.
961 		 */
962 		pmp = MPTOPMP(mp);
963 		pmp->hflags = info.hflags;
964 		cluster = &pmp->iroot->cluster;
965 		for (i = 0; i < cluster->nchains; ++i) {
966 			if (cluster->array[i].chain == NULL)
967 				continue;
968 			hmp = cluster->array[i].chain->hmp;
969 			devvp = hmp->devvp;
970 			error = hammer2_remount(hmp, mp, path,
971 						devvp, cred);
972 			if (error)
973 				break;
974 		}
975 
976 		return error;
977 	}
978 
979 	/*
980 	 * HMP device mount
981 	 *
982 	 * If a path is specified and dev is not an empty string, lookup the
983 	 * name and verify that it referes to a block device.
984 	 *
985 	 * If a path is specified and dev is an empty string we fall through
986 	 * and locate the label in the hmp search.
987 	 */
988 	if (path && *dev != 0) {
989 		error = nlookup_init(&nd, dev, UIO_SYSSPACE, NLC_FOLLOW);
990 		if (error == 0)
991 			error = nlookup(&nd);
992 		if (error == 0)
993 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
994 		nlookup_done(&nd);
995 	} else if (path == NULL) {
996 		/* root mount */
997 		cdev_t cdev = kgetdiskbyname(dev);
998 		error = bdevvp(cdev, &devvp);
999 		if (error)
1000 			kprintf("hammer2: cannot find '%s'\n", dev);
1001 	} else {
1002 		/*
1003 		 * We will locate the hmp using the label in the hmp loop.
1004 		 */
1005 		error = 0;
1006 	}
1007 
1008 	/*
1009 	 * Make sure its a block device.  Do not check to see if it is
1010 	 * already mounted until we determine that its a fresh H2 device.
1011 	 */
1012 	if (error == 0 && devvp) {
1013 		vn_isdisk(devvp, &error);
1014 	}
1015 
1016 	/*
1017 	 * Determine if the device has already been mounted.  After this
1018 	 * check hmp will be non-NULL if we are doing the second or more
1019 	 * hammer2 mounts from the same device.
1020 	 */
1021 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1022 	if (devvp) {
1023 		/*
1024 		 * Match the device.  Due to the way devfs works,
1025 		 * we may not be able to directly match the vnode pointer,
1026 		 * so also check to see if the underlying device matches.
1027 		 */
1028 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1029 			if (hmp->devvp == devvp)
1030 				break;
1031 			if (devvp->v_rdev &&
1032 			    hmp->devvp->v_rdev == devvp->v_rdev) {
1033 				break;
1034 			}
1035 		}
1036 
1037 		/*
1038 		 * If no match this may be a fresh H2 mount, make sure
1039 		 * the device is not mounted on anything else.
1040 		 */
1041 		if (hmp == NULL)
1042 			error = vfs_mountedon(devvp);
1043 	} else if (error == 0) {
1044 		/*
1045 		 * Match the label to a pmp already probed.
1046 		 */
1047 		TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
1048 			for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
1049 				if (pmp->pfs_names[i] &&
1050 				    strcmp(pmp->pfs_names[i], label) == 0) {
1051 					hmp = pmp->pfs_hmps[i];
1052 					break;
1053 				}
1054 			}
1055 			if (hmp)
1056 				break;
1057 		}
1058 		if (hmp == NULL)
1059 			error = ENOENT;
1060 	}
1061 
1062 	/*
1063 	 * Open the device if this isn't a secondary mount and construct
1064 	 * the H2 device mount (hmp).
1065 	 */
1066 	if (hmp == NULL) {
1067 		hammer2_chain_t *schain;
1068 		hammer2_xid_t xid;
1069 
1070 		if (error == 0 && vcount(devvp) > 0) {
1071 			kprintf("Primary device already has references\n");
1072 			error = EBUSY;
1073 		}
1074 
1075 		/*
1076 		 * Now open the device
1077 		 */
1078 		if (error == 0) {
1079 			ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
1080 			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1081 			error = vinvalbuf(devvp, V_SAVE, 0, 0);
1082 			if (error == 0) {
1083 				error = VOP_OPEN(devvp,
1084 					     (ronly ? FREAD : FREAD | FWRITE),
1085 					     FSCRED, NULL);
1086 			}
1087 			vn_unlock(devvp);
1088 		}
1089 		if (error && devvp) {
1090 			vrele(devvp);
1091 			devvp = NULL;
1092 		}
1093 		if (error) {
1094 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1095 			return error;
1096 		}
1097 		hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
1098 		ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
1099 		hmp->ronly = ronly;
1100 		hmp->devvp = devvp;
1101 		hmp->hflags = info.hflags & HMNT2_DEVFLAGS;
1102 		kmalloc_create(&hmp->mchain, "HAMMER2-chains");
1103 		TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
1104 		RB_INIT(&hmp->iotree);
1105 		spin_init(&hmp->io_spin, "hm2mount_io");
1106 		spin_init(&hmp->list_spin, "hm2mount_list");
1107 		TAILQ_INIT(&hmp->flushq);
1108 
1109 		lockinit(&hmp->vollk, "h2vol", 0, 0);
1110 		lockinit(&hmp->bulklk, "h2bulk", 0, 0);
1111 		lockinit(&hmp->bflock, "h2bflk", 0, 0);
1112 
1113 		/*
1114 		 * vchain setup. vchain.data is embedded.
1115 		 * vchain.refs is initialized and will never drop to 0.
1116 		 *
1117 		 * NOTE! voldata is not yet loaded.
1118 		 */
1119 		hmp->vchain.hmp = hmp;
1120 		hmp->vchain.refs = 1;
1121 		hmp->vchain.data = (void *)&hmp->voldata;
1122 		hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
1123 		hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1124 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1125 
1126 		hammer2_chain_core_init(&hmp->vchain);
1127 		/* hmp->vchain.u.xxx is left NULL */
1128 
1129 		/*
1130 		 * fchain setup.  fchain.data is embedded.
1131 		 * fchain.refs is initialized and will never drop to 0.
1132 		 *
1133 		 * The data is not used but needs to be initialized to
1134 		 * pass assertion muster.  We use this chain primarily
1135 		 * as a placeholder for the freemap's top-level RBTREE
1136 		 * so it does not interfere with the volume's topology
1137 		 * RBTREE.
1138 		 */
1139 		hmp->fchain.hmp = hmp;
1140 		hmp->fchain.refs = 1;
1141 		hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
1142 		hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
1143 		hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
1144 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1145 		hmp->fchain.bref.methods =
1146 			HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
1147 			HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
1148 
1149 		hammer2_chain_core_init(&hmp->fchain);
1150 		/* hmp->fchain.u.xxx is left NULL */
1151 
1152 		/*
1153 		 * Install the volume header and initialize fields from
1154 		 * voldata.
1155 		 */
1156 		error = hammer2_install_volume_header(hmp);
1157 		if (error) {
1158 			hammer2_unmount_helper(mp, NULL, hmp);
1159 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1160 			hammer2_vfs_unmount(mp, MNT_FORCE);
1161 			return error;
1162 		}
1163 
1164 		/*
1165 		 * Really important to get these right or flush will get
1166 		 * confused.
1167 		 */
1168 		hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0, NULL);
1169 		kprintf("alloc spmp %p tid %016jx\n",
1170 			hmp->spmp, hmp->voldata.mirror_tid);
1171 		spmp = hmp->spmp;
1172 
1173 		/*
1174 		 * Dummy-up vchain and fchain's modify_tid.  mirror_tid
1175 		 * is inherited from the volume header.
1176 		 */
1177 		xid = 0;
1178 		hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
1179 		hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
1180 		hmp->vchain.pmp = spmp;
1181 		hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
1182 		hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
1183 		hmp->fchain.pmp = spmp;
1184 
1185 		/*
1186 		 * First locate the super-root inode, which is key 0
1187 		 * relative to the volume header's blockset.
1188 		 *
1189 		 * Then locate the root inode by scanning the directory keyspace
1190 		 * represented by the label.
1191 		 */
1192 		parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1193 		schain = hammer2_chain_lookup(&parent, &key_dummy,
1194 				      HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
1195 				      &error, 0);
1196 		hammer2_chain_lookup_done(parent);
1197 		if (schain == NULL) {
1198 			kprintf("hammer2_mount: invalid super-root\n");
1199 			hammer2_unmount_helper(mp, NULL, hmp);
1200 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1201 			hammer2_vfs_unmount(mp, MNT_FORCE);
1202 			return EINVAL;
1203 		}
1204 		if (schain->error) {
1205 			kprintf("hammer2_mount: error %s reading super-root\n",
1206 				hammer2_error_str(schain->error));
1207 			hammer2_chain_unlock(schain);
1208 			hammer2_chain_drop(schain);
1209 			schain = NULL;
1210 			hammer2_unmount_helper(mp, NULL, hmp);
1211 			lockmgr(&hammer2_mntlk, LK_RELEASE);
1212 			hammer2_vfs_unmount(mp, MNT_FORCE);
1213 			return EINVAL;
1214 		}
1215 
1216 		/*
1217 		 * The super-root always uses an inode_tid of 1 when
1218 		 * creating PFSs.
1219 		 */
1220 		spmp->inode_tid = 1;
1221 		spmp->modify_tid = schain->bref.modify_tid + 1;
1222 
1223 		/*
1224 		 * Sanity-check schain's pmp and finish initialization.
1225 		 * Any chain belonging to the super-root topology should
1226 		 * have a NULL pmp (not even set to spmp).
1227 		 */
1228 		ripdata = &hammer2_chain_rdata(schain)->ipdata;
1229 		KKASSERT(schain->pmp == NULL);
1230 		spmp->pfs_clid = ripdata->meta.pfs_clid;
1231 
1232 		/*
1233 		 * Replace the dummy spmp->iroot with a real one.  It's
1234 		 * easier to just do a wholesale replacement than to try
1235 		 * to update the chain and fixup the iroot fields.
1236 		 *
1237 		 * The returned inode is locked with the supplied cluster.
1238 		 */
1239 		cluster = hammer2_cluster_from_chain(schain);
1240 		hammer2_inode_drop(spmp->iroot);
1241 		spmp->iroot = NULL;
1242 		spmp->iroot = hammer2_inode_get(spmp, NULL, cluster, -1);
1243 		spmp->spmp_hmp = hmp;
1244 		spmp->pfs_types[0] = ripdata->meta.pfs_type;
1245 		spmp->pfs_hmps[0] = hmp;
1246 		hammer2_inode_ref(spmp->iroot);
1247 		hammer2_inode_unlock(spmp->iroot);
1248 		hammer2_cluster_unlock(cluster);
1249 		hammer2_cluster_drop(cluster);
1250 		schain = NULL;
1251 		/* leave spmp->iroot with one ref */
1252 
1253 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1254 			error = hammer2_recovery(hmp);
1255 			/* XXX do something with error */
1256 		}
1257 		hammer2_update_pmps(hmp);
1258 		hammer2_iocom_init(hmp);
1259 		hammer2_bulkfree_init(hmp);
1260 
1261 		/*
1262 		 * Ref the cluster management messaging descriptor.  The mount
1263 		 * program deals with the other end of the communications pipe.
1264 		 *
1265 		 * Root mounts typically do not supply one.
1266 		 */
1267 		if (info.cluster_fd >= 0) {
1268 			fp = holdfp(curproc->p_fd, info.cluster_fd, -1);
1269 			if (fp) {
1270 				hammer2_cluster_reconnect(hmp, fp);
1271 			} else {
1272 				kprintf("hammer2_mount: bad cluster_fd!\n");
1273 			}
1274 		}
1275 	} else {
1276 		spmp = hmp->spmp;
1277 		if (info.hflags & HMNT2_DEVFLAGS) {
1278 			kprintf("hammer2: Warning: mount flags pertaining "
1279 				"to the whole device may only be specified "
1280 				"on the first mount of the device: %08x\n",
1281 				info.hflags & HMNT2_DEVFLAGS);
1282 		}
1283 	}
1284 
1285 	/*
1286 	 * Force local mount (disassociate all PFSs from their clusters).
1287 	 * Used primarily for debugging.
1288 	 */
1289 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1290 
1291 	/*
1292 	 * Lookup the mount point under the media-localized super-root.
1293 	 * Scanning hammer2_pfslist doesn't help us because it represents
1294 	 * PFS cluster ids which can aggregate several named PFSs together.
1295 	 *
1296 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1297 	 * up later on.
1298 	 */
1299 	hammer2_inode_lock(spmp->iroot, 0);
1300 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1301 	lhc = hammer2_dirhash(label, strlen(label));
1302 	chain = hammer2_chain_lookup(&parent, &key_next,
1303 				     lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1304 				     &error, 0);
1305 	while (chain) {
1306 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1307 		    strcmp(label, chain->data->ipdata.filename) == 0) {
1308 			break;
1309 		}
1310 		chain = hammer2_chain_next(&parent, chain, &key_next,
1311 					    key_next,
1312 					    lhc + HAMMER2_DIRHASH_LOMASK,
1313 					    &error, 0);
1314 	}
1315 	if (parent) {
1316 		hammer2_chain_unlock(parent);
1317 		hammer2_chain_drop(parent);
1318 	}
1319 	hammer2_inode_unlock(spmp->iroot);
1320 
1321 	/*
1322 	 * PFS could not be found?
1323 	 */
1324 	if (chain == NULL) {
1325 		if (error)
1326 			kprintf("hammer2_mount: PFS label I/O error\n");
1327 		else
1328 			kprintf("hammer2_mount: PFS label not found\n");
1329 		hammer2_unmount_helper(mp, NULL, hmp);
1330 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1331 		hammer2_vfs_unmount(mp, MNT_FORCE);
1332 
1333 		return EINVAL;
1334 	}
1335 
1336 	/*
1337 	 * Acquire the pmp structure (it should have already been allocated
1338 	 * via hammer2_update_pmps() so do not pass cluster in to add to
1339 	 * available chains).
1340 	 *
1341 	 * Check if the cluster has already been mounted.  A cluster can
1342 	 * only be mounted once, use null mounts to mount additional copies.
1343 	 */
1344 	if (chain->error) {
1345 		kprintf("hammer2_mount: PFS label I/O error\n");
1346 	} else {
1347 		ripdata = &chain->data->ipdata;
1348 		bref = chain->bref;
1349 		pmp = hammer2_pfsalloc(NULL, ripdata,
1350 				       bref.modify_tid, force_local);
1351 	}
1352 	hammer2_chain_unlock(chain);
1353 	hammer2_chain_drop(chain);
1354 
1355 	/*
1356 	 * Finish the mount
1357 	 */
1358         kprintf("hammer2_mount hmp=%p pmp=%p\n", hmp, pmp);
1359 
1360 	if (pmp->mp) {
1361 		kprintf("hammer2_mount: PFS already mounted!\n");
1362 		hammer2_unmount_helper(mp, NULL, hmp);
1363 		lockmgr(&hammer2_mntlk, LK_RELEASE);
1364 		hammer2_vfs_unmount(mp, MNT_FORCE);
1365 
1366 		return EBUSY;
1367 	}
1368 
1369 	pmp->hflags = info.hflags;
1370         mp->mnt_flag |= MNT_LOCAL;
1371         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1372         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1373 
1374         /*
1375          * required mount structure initializations
1376          */
1377         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1378         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1379 
1380         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1381         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1382 
1383         /*
1384          * Optional fields
1385          */
1386         mp->mnt_iosize_max = MAXPHYS;
1387 
1388 	/*
1389 	 * Connect up mount pointers.
1390 	 */
1391 	hammer2_mount_helper(mp, pmp);
1392 
1393         lockmgr(&hammer2_mntlk, LK_RELEASE);
1394 
1395 	/*
1396 	 * Finish setup
1397 	 */
1398 	vfs_getnewfsid(mp);
1399 	vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1400 	vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1401 	vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1402 
1403 	if (path) {
1404 		copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1405 			  MNAMELEN - 1, &size);
1406 		bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1407 	} /* else root mount, already in there */
1408 
1409 	bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1410 	if (path) {
1411 		copyinstr(path, mp->mnt_stat.f_mntonname,
1412 			  sizeof(mp->mnt_stat.f_mntonname) - 1,
1413 			  &size);
1414 	} else {
1415 		/* root mount */
1416 		mp->mnt_stat.f_mntonname[0] = '/';
1417 	}
1418 
1419 	/*
1420 	 * Initial statfs to prime mnt_stat.
1421 	 */
1422 	hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1423 
1424 	return 0;
1425 }
1426 
1427 /*
1428  * Scan PFSs under the super-root and create hammer2_pfs structures.
1429  */
1430 static
1431 void
1432 hammer2_update_pmps(hammer2_dev_t *hmp)
1433 {
1434 	const hammer2_inode_data_t *ripdata;
1435 	hammer2_chain_t *parent;
1436 	hammer2_chain_t *chain;
1437 	hammer2_blockref_t bref;
1438 	hammer2_dev_t *force_local;
1439 	hammer2_pfs_t *spmp;
1440 	hammer2_pfs_t *pmp;
1441 	hammer2_key_t key_next;
1442 	int error;
1443 
1444 	/*
1445 	 * Force local mount (disassociate all PFSs from their clusters).
1446 	 * Used primarily for debugging.
1447 	 */
1448 	force_local = (hmp->hflags & HMNT2_LOCAL) ? hmp : NULL;
1449 
1450 	/*
1451 	 * Lookup mount point under the media-localized super-root.
1452 	 *
1453 	 * cluster->pmp will incorrectly point to spmp and must be fixed
1454 	 * up later on.
1455 	 */
1456 	spmp = hmp->spmp;
1457 	hammer2_inode_lock(spmp->iroot, 0);
1458 	parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1459 	chain = hammer2_chain_lookup(&parent, &key_next,
1460 					 HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1461 					 &error, 0);
1462 	while (chain) {
1463 		if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
1464 			continue;
1465 		if (chain->error) {
1466 			kprintf("I/O error scanning PFS labels\n");
1467 		} else {
1468 			ripdata = &chain->data->ipdata;
1469 			bref = chain->bref;
1470 			kprintf("ADD LOCAL PFS: %s\n", ripdata->filename);
1471 
1472 			pmp = hammer2_pfsalloc(chain, ripdata,
1473 					       bref.modify_tid, force_local);
1474 		}
1475 		chain = hammer2_chain_next(&parent, chain, &key_next,
1476 					   key_next, HAMMER2_KEY_MAX,
1477 					   &error, 0);
1478 	}
1479 	if (parent) {
1480 		hammer2_chain_unlock(parent);
1481 		hammer2_chain_drop(parent);
1482 	}
1483 	hammer2_inode_unlock(spmp->iroot);
1484 }
1485 
1486 static
1487 int
1488 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1489 		struct vnode *devvp, struct ucred *cred)
1490 {
1491 	int error;
1492 
1493 	if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
1494 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1495 		VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, NULL);
1496 		vn_unlock(devvp);
1497 		error = hammer2_recovery(hmp);
1498 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1499 		if (error == 0) {
1500 			VOP_CLOSE(devvp, FREAD, NULL);
1501 			hmp->ronly = 0;
1502 		} else {
1503 			VOP_CLOSE(devvp, FREAD | FWRITE, NULL);
1504 		}
1505 		vn_unlock(devvp);
1506 	} else {
1507 		error = 0;
1508 	}
1509 	return error;
1510 }
1511 
1512 static
1513 int
1514 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1515 {
1516 	hammer2_pfs_t *pmp;
1517 	int flags;
1518 	int error = 0;
1519 
1520 	pmp = MPTOPMP(mp);
1521 
1522 	if (pmp == NULL)
1523 		return(0);
1524 
1525 	lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1526 
1527 	/*
1528 	 * If mount initialization proceeded far enough we must flush
1529 	 * its vnodes and sync the underlying mount points.  Three syncs
1530 	 * are required to fully flush the filesystem (freemap updates lag
1531 	 * by one flush, and one extra for safety).
1532 	 */
1533 	if (mntflags & MNT_FORCE)
1534 		flags = FORCECLOSE;
1535 	else
1536 		flags = 0;
1537 	if (pmp->iroot) {
1538 		error = vflush(mp, 0, flags);
1539 		if (error)
1540 			goto failed;
1541 		hammer2_vfs_sync(mp, MNT_WAIT);
1542 		hammer2_vfs_sync(mp, MNT_WAIT);
1543 		hammer2_vfs_sync(mp, MNT_WAIT);
1544 	}
1545 
1546 	/*
1547 	 * Cleanup the frontend support XOPS threads
1548 	 */
1549 	hammer2_xop_helper_cleanup(pmp);
1550 
1551 	if (pmp->mp)
1552 		hammer2_unmount_helper(mp, pmp, NULL);
1553 
1554 	error = 0;
1555 failed:
1556 	lockmgr(&hammer2_mntlk, LK_RELEASE);
1557 
1558 	return (error);
1559 }
1560 
1561 /*
1562  * Mount helper, hook the system mount into our PFS.
1563  * The mount lock is held.
1564  *
1565  * We must bump the mount_count on related devices for any
1566  * mounted PFSs.
1567  */
1568 static
1569 void
1570 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1571 {
1572 	hammer2_cluster_t *cluster;
1573 	hammer2_chain_t *rchain;
1574 	int i;
1575 
1576         mp->mnt_data = (qaddr_t)pmp;
1577 	pmp->mp = mp;
1578 
1579 	/*
1580 	 * After pmp->mp is set we have to adjust hmp->mount_count.
1581 	 */
1582 	cluster = &pmp->iroot->cluster;
1583 	for (i = 0; i < cluster->nchains; ++i) {
1584 		rchain = cluster->array[i].chain;
1585 		if (rchain == NULL)
1586 			continue;
1587 		++rchain->hmp->mount_count;
1588 		kprintf("hammer2_mount hmp=%p ++mount_count=%d\n",
1589 			rchain->hmp, rchain->hmp->mount_count);
1590 	}
1591 
1592 	/*
1593 	 * Create missing Xop threads
1594 	 */
1595 	hammer2_xop_helper_create(pmp);
1596 }
1597 
1598 /*
1599  * Mount helper, unhook the system mount from our PFS.
1600  * The mount lock is held.
1601  *
1602  * If hmp is supplied a mount responsible for being the first to open
1603  * the block device failed and the block device and all PFSs using the
1604  * block device must be cleaned up.
1605  *
1606  * If pmp is supplied multiple devices might be backing the PFS and each
1607  * must be disconnected.  This might not be the last PFS using some of the
1608  * underlying devices.  Also, we have to adjust our hmp->mount_count
1609  * accounting for the devices backing the pmp which is now undergoing an
1610  * unmount.
1611  */
1612 static
1613 void
1614 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1615 {
1616 	hammer2_cluster_t *cluster;
1617 	hammer2_chain_t *rchain;
1618 	struct vnode *devvp;
1619 	int dumpcnt;
1620 	int ronly;
1621 	int i;
1622 
1623 	/*
1624 	 * If no device supplied this is a high-level unmount and we have to
1625 	 * to disconnect the mount, adjust mount_count, and locate devices
1626 	 * that might now have no mounts.
1627 	 */
1628 	if (pmp) {
1629 		KKASSERT(hmp == NULL);
1630 		KKASSERT((void *)(intptr_t)mp->mnt_data == pmp);
1631 		pmp->mp = NULL;
1632 		mp->mnt_data = NULL;
1633 
1634 		/*
1635 		 * After pmp->mp is cleared we have to account for
1636 		 * mount_count.
1637 		 */
1638 		cluster = &pmp->iroot->cluster;
1639 		for (i = 0; i < cluster->nchains; ++i) {
1640 			rchain = cluster->array[i].chain;
1641 			if (rchain == NULL)
1642 				continue;
1643 			--rchain->hmp->mount_count;
1644 			kprintf("hammer2_unmount hmp=%p --mount_count=%d\n",
1645 				rchain->hmp, rchain->hmp->mount_count);
1646 			/* scrapping hmp now may invalidate the pmp */
1647 		}
1648 again:
1649 		TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1650 			if (hmp->mount_count == 0) {
1651 				hammer2_unmount_helper(NULL, NULL, hmp);
1652 				goto again;
1653 			}
1654 		}
1655 		return;
1656 	}
1657 
1658 	/*
1659 	 * Try to terminate the block device.  We can't terminate it if
1660 	 * there are still PFSs referencing it.
1661 	 */
1662 	kprintf("hammer2_unmount hmp=%p mount_count=%d\n",
1663 		hmp, hmp->mount_count);
1664 	if (hmp->mount_count)
1665 		return;
1666 
1667 	hammer2_bulkfree_uninit(hmp);
1668 	hammer2_pfsfree_scan(hmp);
1669 	hammer2_dev_exlock(hmp);	/* XXX order */
1670 
1671 	/*
1672 	 * Cycle the volume data lock as a safety (probably not needed any
1673 	 * more).  To ensure everything is out we need to flush at least
1674 	 * three times.  (1) The running of the sideq can dirty the
1675 	 * filesystem, (2) A normal flush can dirty the freemap, and
1676 	 * (3) ensure that the freemap is fully synchronized.
1677 	 *
1678 	 * The next mount's recovery scan can clean everything up but we want
1679 	 * to leave the filesystem in a 100% clean state on a normal unmount.
1680 	 */
1681 #if 0
1682 	hammer2_voldata_lock(hmp);
1683 	hammer2_voldata_unlock(hmp);
1684 #endif
1685 	hammer2_iocom_uninit(hmp);
1686 
1687 	if ((hmp->vchain.flags | hmp->fchain.flags) &
1688 	    HAMMER2_CHAIN_FLUSH_MASK) {
1689 		kprintf("hammer2_unmount: chains left over "
1690 			"after final sync\n");
1691 		kprintf("    vchain %08x\n", hmp->vchain.flags);
1692 		kprintf("    fchain %08x\n", hmp->fchain.flags);
1693 
1694 		if (hammer2_debug & 0x0010)
1695 			Debugger("entered debugger");
1696 	}
1697 
1698 	KKASSERT(hmp->spmp == NULL);
1699 
1700 	/*
1701 	 * Finish up with the device vnode
1702 	 */
1703 	if ((devvp = hmp->devvp) != NULL) {
1704 		ronly = hmp->ronly;
1705 		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1706 		kprintf("hammer2_unmount(A): devvp %s rbdirty %p ronly=%d\n",
1707 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree),
1708 			ronly);
1709 		vinvalbuf(devvp, (ronly ? 0 : V_SAVE), 0, 0);
1710 		kprintf("hammer2_unmount(B): devvp %s rbdirty %p\n",
1711 			hmp->devrepname, RB_ROOT(&devvp->v_rbdirty_tree));
1712 		hmp->devvp = NULL;
1713 		VOP_CLOSE(devvp, (ronly ? FREAD : FREAD|FWRITE), NULL);
1714 		vn_unlock(devvp);
1715 		vrele(devvp);
1716 		devvp = NULL;
1717 	}
1718 
1719 	/*
1720 	 * Clear vchain/fchain flags that might prevent final cleanup
1721 	 * of these chains.
1722 	 */
1723 	if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1724 		atomic_add_long(&hammer2_count_modified_chains, -1);
1725 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_MODIFIED);
1726 		hammer2_pfs_memory_wakeup(hmp->vchain.pmp);
1727 	}
1728 	if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1729 		atomic_clear_int(&hmp->vchain.flags, HAMMER2_CHAIN_UPDATE);
1730 	}
1731 
1732 	if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1733 		atomic_add_long(&hammer2_count_modified_chains, -1);
1734 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_MODIFIED);
1735 		hammer2_pfs_memory_wakeup(hmp->fchain.pmp);
1736 	}
1737 	if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1738 		atomic_clear_int(&hmp->fchain.flags, HAMMER2_CHAIN_UPDATE);
1739 	}
1740 
1741 	/*
1742 	 * Final drop of embedded freemap root chain to
1743 	 * clean up fchain.core (fchain structure is not
1744 	 * flagged ALLOCATED so it is cleaned out and then
1745 	 * left to rot).
1746 	 */
1747 	hammer2_chain_drop(&hmp->fchain);
1748 
1749 	/*
1750 	 * Final drop of embedded volume root chain to clean
1751 	 * up vchain.core (vchain structure is not flagged
1752 	 * ALLOCATED so it is cleaned out and then left to
1753 	 * rot).
1754 	 */
1755 	dumpcnt = 50;
1756 	hammer2_dump_chain(&hmp->vchain, 0, &dumpcnt, 'v');
1757 	dumpcnt = 50;
1758 	hammer2_dump_chain(&hmp->fchain, 0, &dumpcnt, 'f');
1759 	hammer2_dev_unlock(hmp);
1760 	hammer2_chain_drop(&hmp->vchain);
1761 
1762 	hammer2_io_cleanup(hmp, &hmp->iotree);
1763 	if (hmp->iofree_count) {
1764 		kprintf("io_cleanup: %d I/O's left hanging\n",
1765 			hmp->iofree_count);
1766 	}
1767 
1768 	TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1769 	kmalloc_destroy(&hmp->mchain);
1770 	kfree(hmp, M_HAMMER2);
1771 }
1772 
1773 int
1774 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1775 		 ino_t ino, struct vnode **vpp)
1776 {
1777 	hammer2_xop_lookup_t *xop;
1778 	hammer2_pfs_t *pmp;
1779 	hammer2_inode_t *ip;
1780 	hammer2_tid_t inum;
1781 	int error;
1782 
1783 	inum = (hammer2_tid_t)ino & HAMMER2_DIRHASH_USERMSK;
1784 
1785 	error = 0;
1786 	pmp = MPTOPMP(mp);
1787 
1788 	/*
1789 	 * Easy if we already have it cached
1790 	 */
1791 	ip = hammer2_inode_lookup(pmp, inum);
1792 	if (ip) {
1793 		hammer2_inode_lock(ip, HAMMER2_RESOLVE_SHARED);
1794 		*vpp = hammer2_igetv(ip, &error);
1795 		hammer2_inode_unlock(ip);
1796 		hammer2_inode_drop(ip);		/* from lookup */
1797 
1798 		return error;
1799 	}
1800 
1801 	/*
1802 	 * Otherwise we have to find the inode
1803 	 */
1804 	xop = hammer2_xop_alloc(pmp->iroot, 0);
1805 	xop->lhc = inum;
1806 	hammer2_xop_start(&xop->head, hammer2_xop_lookup);
1807 	error = hammer2_xop_collect(&xop->head, 0);
1808 
1809 	if (error == 0) {
1810 		if (hammer2_cluster_rdata(&xop->head.cluster) == NULL) {
1811 			kprintf("vget: no collect error but also no rdata\n");
1812 			kprintf("xop %p\n", xop);
1813 			while ((hammer2_debug & 0x80000) == 0) {
1814 				tsleep(xop, PCATCH, "wait", hz * 10);
1815 			}
1816 			ip = NULL;
1817 		} else {
1818 			ip = hammer2_inode_get(pmp, NULL, &xop->head.cluster, -1);
1819 		}
1820 	}
1821 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1822 
1823 	if (ip) {
1824 		*vpp = hammer2_igetv(ip, &error);
1825 		hammer2_inode_unlock(ip);
1826 	} else {
1827 		*vpp = NULL;
1828 		error = ENOENT;
1829 	}
1830 	return (error);
1831 }
1832 
1833 static
1834 int
1835 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1836 {
1837 	hammer2_pfs_t *pmp;
1838 	struct vnode *vp;
1839 	int error;
1840 
1841 	pmp = MPTOPMP(mp);
1842 	if (pmp->iroot == NULL) {
1843 		*vpp = NULL;
1844 		return EINVAL;
1845 	}
1846 
1847 	error = 0;
1848 	hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1849 
1850 	while (pmp->inode_tid == 0) {
1851 		hammer2_xop_ipcluster_t *xop;
1852 		hammer2_inode_meta_t *meta;
1853 
1854 		xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1855 		hammer2_xop_start(&xop->head, hammer2_xop_ipcluster);
1856 		error = hammer2_xop_collect(&xop->head, 0);
1857 
1858 		if (error == 0) {
1859 			meta = &xop->head.cluster.focus->data->ipdata.meta;
1860 			pmp->iroot->meta = *meta;
1861 			pmp->inode_tid = meta->pfs_inum + 1;
1862 			if (pmp->inode_tid < HAMMER2_INODE_START)
1863 				pmp->inode_tid = HAMMER2_INODE_START;
1864 			pmp->modify_tid =
1865 				xop->head.cluster.focus->bref.modify_tid + 1;
1866 			kprintf("PFS: Starting inode %jd\n",
1867 				(intmax_t)pmp->inode_tid);
1868 			kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1869 				pmp->inode_tid, pmp->modify_tid);
1870 			wakeup(&pmp->iroot);
1871 
1872 			hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1873 
1874 			/*
1875 			 * Prime the mount info.
1876 			 */
1877 			hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
1878 			break;
1879 		}
1880 
1881 		/*
1882 		 * Loop, try again
1883 		 */
1884 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1885 		hammer2_inode_unlock(pmp->iroot);
1886 		error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
1887 		hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1888 		if (error == EINTR)
1889 			break;
1890 	}
1891 
1892 	if (error) {
1893 		hammer2_inode_unlock(pmp->iroot);
1894 		*vpp = NULL;
1895 	} else {
1896 		vp = hammer2_igetv(pmp->iroot, &error);
1897 		hammer2_inode_unlock(pmp->iroot);
1898 		*vpp = vp;
1899 	}
1900 
1901 	return (error);
1902 }
1903 
1904 /*
1905  * Filesystem status
1906  *
1907  * XXX incorporate ipdata->meta.inode_quota and data_quota
1908  */
1909 static
1910 int
1911 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
1912 {
1913 	hammer2_pfs_t *pmp;
1914 	hammer2_dev_t *hmp;
1915 	hammer2_blockref_t bref;
1916 	int i;
1917 
1918 	/*
1919 	 * NOTE: iroot might not have validated the cluster yet.
1920 	 */
1921 	pmp = MPTOPMP(mp);
1922 
1923 	mp->mnt_stat.f_files = 0;
1924 	mp->mnt_stat.f_ffree = 0;
1925 	mp->mnt_stat.f_blocks = 0;
1926 	mp->mnt_stat.f_bfree = 0;
1927 	mp->mnt_stat.f_bavail = 0;
1928 
1929 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1930 		hmp = pmp->pfs_hmps[i];
1931 		if (hmp == NULL)
1932 			continue;
1933 		if (pmp->iroot->cluster.array[i].chain)
1934 			bref = pmp->iroot->cluster.array[i].chain->bref;
1935 		else
1936 			bzero(&bref, sizeof(bref));
1937 
1938 		mp->mnt_stat.f_files = bref.embed.stats.inode_count;
1939 		mp->mnt_stat.f_ffree = 0;
1940 		mp->mnt_stat.f_blocks = hmp->voldata.allocator_size /
1941 					mp->mnt_vstat.f_bsize;
1942 		mp->mnt_stat.f_bfree = hmp->voldata.allocator_free /
1943 					mp->mnt_vstat.f_bsize;
1944 		mp->mnt_stat.f_bavail = mp->mnt_stat.f_bfree;
1945 
1946 		if (cred && cred->cr_uid != 0) {
1947 			uint64_t adj;
1948 
1949 			/* 5% */
1950 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
1951 			mp->mnt_stat.f_blocks -= adj;
1952 			mp->mnt_stat.f_bfree -= adj;
1953 			mp->mnt_stat.f_bavail -= adj;
1954 		}
1955 
1956 		*sbp = mp->mnt_stat;
1957 	}
1958 	return (0);
1959 }
1960 
1961 static
1962 int
1963 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
1964 {
1965 	hammer2_pfs_t *pmp;
1966 	hammer2_dev_t *hmp;
1967 	hammer2_blockref_t bref;
1968 	int i;
1969 
1970 	/*
1971 	 * NOTE: iroot might not have validated the cluster yet.
1972 	 */
1973 	pmp = MPTOPMP(mp);
1974 
1975 	mp->mnt_vstat.f_bsize = 0;
1976 	mp->mnt_vstat.f_files = 0;
1977 	mp->mnt_vstat.f_ffree = 0;
1978 	mp->mnt_vstat.f_blocks = 0;
1979 	mp->mnt_vstat.f_bfree = 0;
1980 	mp->mnt_vstat.f_bavail = 0;
1981 
1982 	for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1983 		hmp = pmp->pfs_hmps[i];
1984 		if (hmp == NULL)
1985 			continue;
1986 		if (pmp->iroot->cluster.array[i].chain)
1987 			bref = pmp->iroot->cluster.array[i].chain->bref;
1988 		else
1989 			bzero(&bref, sizeof(bref));
1990 
1991 		mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1992 		mp->mnt_vstat.f_files = bref.embed.stats.inode_count;
1993 		mp->mnt_vstat.f_ffree = 0;
1994 		mp->mnt_vstat.f_blocks = hmp->voldata.allocator_size /
1995 					mp->mnt_vstat.f_bsize;
1996 		mp->mnt_vstat.f_bfree = hmp->voldata.allocator_free /
1997 					mp->mnt_vstat.f_bsize;
1998 		mp->mnt_vstat.f_bavail = mp->mnt_vstat.f_bfree;
1999 
2000 		if (cred && cred->cr_uid != 0) {
2001 			uint64_t adj;
2002 
2003 			/* 5% */
2004 			adj = hmp->free_reserved / mp->mnt_vstat.f_bsize;
2005 			mp->mnt_vstat.f_blocks -= adj;
2006 			mp->mnt_vstat.f_bfree -= adj;
2007 			mp->mnt_vstat.f_bavail -= adj;
2008 		}
2009 
2010 		*sbp = mp->mnt_vstat;
2011 	}
2012 	return (0);
2013 }
2014 
2015 /*
2016  * Mount-time recovery (RW mounts)
2017  *
2018  * Updates to the free block table are allowed to lag flushes by one
2019  * transaction.  In case of a crash, then on a fresh mount we must do an
2020  * incremental scan of the last committed transaction id and make sure that
2021  * all related blocks have been marked allocated.
2022  *
2023  * The super-root topology and each PFS has its own transaction id domain,
2024  * so we must track PFS boundary transitions.
2025  */
2026 struct hammer2_recovery_elm {
2027 	TAILQ_ENTRY(hammer2_recovery_elm) entry;
2028 	hammer2_chain_t *chain;
2029 	hammer2_tid_t sync_tid;
2030 };
2031 
2032 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
2033 
2034 struct hammer2_recovery_info {
2035 	struct hammer2_recovery_list list;
2036 	hammer2_tid_t	mtid;
2037 	int	depth;
2038 };
2039 
2040 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
2041 			hammer2_chain_t *parent,
2042 			struct hammer2_recovery_info *info,
2043 			hammer2_tid_t sync_tid);
2044 
2045 #define HAMMER2_RECOVERY_MAXDEPTH	10
2046 
2047 static
2048 int
2049 hammer2_recovery(hammer2_dev_t *hmp)
2050 {
2051 	struct hammer2_recovery_info info;
2052 	struct hammer2_recovery_elm *elm;
2053 	hammer2_chain_t *parent;
2054 	hammer2_tid_t sync_tid;
2055 	hammer2_tid_t mirror_tid;
2056 	int error;
2057 
2058 	hammer2_trans_init(hmp->spmp, 0);
2059 
2060 	sync_tid = hmp->voldata.freemap_tid;
2061 	mirror_tid = hmp->voldata.mirror_tid;
2062 
2063 	kprintf("hammer2 mount \"%s\": ", hmp->devrepname);
2064 	if (sync_tid >= mirror_tid) {
2065 		kprintf(" no recovery needed\n");
2066 	} else {
2067 		kprintf(" freemap recovery %016jx-%016jx\n",
2068 			sync_tid + 1, mirror_tid);
2069 	}
2070 
2071 	TAILQ_INIT(&info.list);
2072 	info.depth = 0;
2073 	parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
2074 	error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
2075 	hammer2_chain_lookup_done(parent);
2076 
2077 	while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
2078 		TAILQ_REMOVE(&info.list, elm, entry);
2079 		parent = elm->chain;
2080 		sync_tid = elm->sync_tid;
2081 		kfree(elm, M_HAMMER2);
2082 
2083 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2084 		error |= hammer2_recovery_scan(hmp, parent, &info,
2085 					      hmp->voldata.freemap_tid);
2086 		hammer2_chain_unlock(parent);
2087 		hammer2_chain_drop(parent);	/* drop elm->chain ref */
2088 	}
2089 	hammer2_trans_done(hmp->spmp);
2090 
2091 	return error;
2092 }
2093 
2094 static
2095 int
2096 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
2097 		      struct hammer2_recovery_info *info,
2098 		      hammer2_tid_t sync_tid)
2099 {
2100 	const hammer2_inode_data_t *ripdata;
2101 	hammer2_chain_t *chain;
2102 	hammer2_blockref_t bref;
2103 	int tmp_error;
2104 	int rup_error;
2105 	int error;
2106 	int first;
2107 
2108 	/*
2109 	 * Adjust freemap to ensure that the block(s) are marked allocated.
2110 	 */
2111 	if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
2112 		hammer2_freemap_adjust(hmp, &parent->bref,
2113 				       HAMMER2_FREEMAP_DORECOVER);
2114 	}
2115 
2116 	/*
2117 	 * Check type for recursive scan
2118 	 */
2119 	switch(parent->bref.type) {
2120 	case HAMMER2_BREF_TYPE_VOLUME:
2121 		/* data already instantiated */
2122 		break;
2123 	case HAMMER2_BREF_TYPE_INODE:
2124 		/*
2125 		 * Must instantiate data for DIRECTDATA test and also
2126 		 * for recursion.
2127 		 */
2128 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2129 		ripdata = &hammer2_chain_rdata(parent)->ipdata;
2130 		if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
2131 			/* not applicable to recovery scan */
2132 			hammer2_chain_unlock(parent);
2133 			return 0;
2134 		}
2135 		hammer2_chain_unlock(parent);
2136 		break;
2137 	case HAMMER2_BREF_TYPE_INDIRECT:
2138 		/*
2139 		 * Must instantiate data for recursion
2140 		 */
2141 		hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
2142 		hammer2_chain_unlock(parent);
2143 		break;
2144 	case HAMMER2_BREF_TYPE_DIRENT:
2145 	case HAMMER2_BREF_TYPE_DATA:
2146 	case HAMMER2_BREF_TYPE_FREEMAP:
2147 	case HAMMER2_BREF_TYPE_FREEMAP_NODE:
2148 	case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
2149 		/* not applicable to recovery scan */
2150 		return 0;
2151 		break;
2152 	default:
2153 		return HAMMER2_ERROR_BADBREF;
2154 	}
2155 
2156 	/*
2157 	 * Defer operation if depth limit reached or if we are crossing a
2158 	 * PFS boundary.
2159 	 */
2160 	if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
2161 		struct hammer2_recovery_elm *elm;
2162 
2163 		elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
2164 		elm->chain = parent;
2165 		elm->sync_tid = sync_tid;
2166 		hammer2_chain_ref(parent);
2167 		TAILQ_INSERT_TAIL(&info->list, elm, entry);
2168 		/* unlocked by caller */
2169 
2170 		return(0);
2171 	}
2172 
2173 
2174 	/*
2175 	 * Recursive scan of the last flushed transaction only.  We are
2176 	 * doing this without pmp assignments so don't leave the chains
2177 	 * hanging around after we are done with them.
2178 	 *
2179 	 * error	Cumulative error this level only
2180 	 * rup_error	Cumulative error for recursion
2181 	 * tmp_error	Specific non-cumulative recursion error
2182 	 */
2183 	chain = NULL;
2184 	first = 1;
2185 	rup_error = 0;
2186 	error = 0;
2187 
2188 	for (;;) {
2189 		error |= hammer2_chain_scan(parent, &chain, &bref,
2190 					    &first,
2191 					    HAMMER2_LOOKUP_NODATA);
2192 
2193 		/*
2194 		 * Problem during scan or EOF
2195 		 */
2196 		if (error)
2197 			break;
2198 
2199 		/*
2200 		 * If this is a leaf
2201 		 */
2202 		if (chain == NULL) {
2203 			if (bref.mirror_tid > sync_tid) {
2204 				hammer2_freemap_adjust(hmp, &bref,
2205 						     HAMMER2_FREEMAP_DORECOVER);
2206 			}
2207 			continue;
2208 		}
2209 
2210 		/*
2211 		 * This may or may not be a recursive node.
2212 		 */
2213 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
2214 		if (bref.mirror_tid > sync_tid) {
2215 			++info->depth;
2216 			tmp_error = hammer2_recovery_scan(hmp, chain,
2217 							   info, sync_tid);
2218 			--info->depth;
2219 		} else {
2220 			tmp_error = 0;
2221 		}
2222 
2223 		/*
2224 		 * Flush the recovery at the PFS boundary to stage it for
2225 		 * the final flush of the super-root topology.
2226 		 */
2227 		if (tmp_error == 0 &&
2228 		    (bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
2229 		    (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
2230 			hammer2_flush(chain, HAMMER2_FLUSH_TOP);
2231 		}
2232 		rup_error |= tmp_error;
2233 	}
2234 	return ((error | rup_error) & ~HAMMER2_ERROR_EOF);
2235 }
2236 
2237 /*
2238  * Sync a mount point; this is called on a per-mount basis from the
2239  * filesystem syncer process periodically and whenever a user issues
2240  * a sync.
2241  */
2242 int
2243 hammer2_vfs_sync(struct mount *mp, int waitfor)
2244 {
2245 	hammer2_xop_flush_t *xop;
2246 	struct hammer2_sync_info info;
2247 	hammer2_inode_t *iroot;
2248 	hammer2_pfs_t *pmp;
2249 	int flags;
2250 	int error;
2251 
2252 	pmp = MPTOPMP(mp);
2253 	iroot = pmp->iroot;
2254 	KKASSERT(iroot);
2255 	KKASSERT(iroot->pmp == pmp);
2256 
2257 	/*
2258 	 * We can't acquire locks on existing vnodes while in a transaction
2259 	 * without risking a deadlock.  This assumes that vfsync() can be
2260 	 * called without the vnode locked (which it can in DragonFly).
2261 	 * Otherwise we'd have to implement a multi-pass or flag the lock
2262 	 * failures and retry.
2263 	 *
2264 	 * The reclamation code interlocks with the sync list's token
2265 	 * (by removing the vnode from the scan list) before unlocking
2266 	 * the inode, giving us time to ref the inode.
2267 	 */
2268 	/*flags = VMSC_GETVP;*/
2269 	flags = 0;
2270 	if (waitfor & MNT_LAZY)
2271 		flags |= VMSC_ONEPASS;
2272 
2273 	/*
2274 	 * Preflush the vnodes using a normal transaction before interlocking
2275 	 * with a flush transaction.  We do this to try to run as much of
2276 	 * the compression as possible outside the flush transaction.
2277 	 *
2278 	 * For efficiency do an async pass before making sure with a
2279 	 * synchronous pass on all related buffer cache buffers.
2280 	 */
2281 	hammer2_trans_init(pmp, 0);
2282 	info.error = 0;
2283 	info.waitfor = MNT_NOWAIT;
2284 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2285 	info.waitfor = MNT_WAIT;
2286 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2287 	hammer2_trans_done(pmp);
2288 
2289 	/*
2290 	 * Start our flush transaction.  This does not return until all
2291 	 * concurrent transactions have completed and will prevent any
2292 	 * new transactions from running concurrently, except for the
2293 	 * buffer cache transactions.
2294 	 *
2295 	 * NOTE!  It is still possible for the paging code to push pages
2296 	 *	  out via a UIO_NOCOPY hammer2_vop_write() during the main
2297 	 *	  flush.
2298 	 */
2299 	hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH);
2300 	hammer2_inode_run_sideq(pmp);
2301 
2302 	info.error = 0;
2303 	info.waitfor = MNT_NOWAIT;
2304 	vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
2305 	info.waitfor = MNT_WAIT;
2306 	vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2307 	hammer2_bioq_sync(pmp);
2308 
2309 	/*
2310 	 * Use the XOP interface to concurrently flush all nodes to
2311 	 * synchronize the PFSROOT subtopology to the media.  A standard
2312 	 * end-of-scan ENOENT error indicates cluster sufficiency.
2313 	 *
2314 	 * Note that this flush will not be visible on crash recovery until
2315 	 * we flush the super-root topology in the next loop.
2316 	 *
2317 	 * XXX For now wait for all flushes to complete.
2318 	 */
2319 	if (iroot) {
2320 		xop = hammer2_xop_alloc(iroot, HAMMER2_XOP_MODIFYING);
2321 		hammer2_xop_start(&xop->head, hammer2_inode_xop_flush);
2322 		error = hammer2_xop_collect(&xop->head,
2323 					    HAMMER2_XOP_COLLECT_WAITALL);
2324 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2325 		if (error == HAMMER2_ERROR_ENOENT)
2326 			error = 0;
2327 		else
2328 			error = hammer2_error_to_errno(error);
2329 	} else {
2330 		error = 0;
2331 	}
2332 	hammer2_trans_done(pmp);
2333 
2334 	return (error);
2335 }
2336 
2337 /*
2338  * Sync passes.
2339  *
2340  * Note that we ignore the tranasction mtid we got above.  Instead,
2341  * each vfsync below will ultimately get its own via TRANS_BUFCACHE
2342  * transactions.
2343  */
2344 static int
2345 hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
2346 {
2347 	struct hammer2_sync_info *info = data;
2348 	hammer2_inode_t *ip;
2349 	int error;
2350 
2351 	/*
2352 	 * Degenerate cases.  Note that ip == NULL typically means the
2353 	 * syncer vnode itself and we don't want to vclrisdirty() in that
2354 	 * situation.
2355 	 */
2356 	ip = VTOI(vp);
2357 	if (ip == NULL) {
2358 		return(0);
2359 	}
2360 	if (vp->v_type == VNON || vp->v_type == VBAD) {
2361 		vclrisdirty(vp);
2362 		return(0);
2363 	}
2364 
2365 	/*
2366 	 * VOP_FSYNC will start a new transaction so replicate some code
2367 	 * here to do it inline (see hammer2_vop_fsync()).
2368 	 *
2369 	 * WARNING: The vfsync interacts with the buffer cache and might
2370 	 *          block, we can't hold the inode lock at that time.
2371 	 *	    However, we MUST ref ip before blocking to ensure that
2372 	 *	    it isn't ripped out from under us (since we do not
2373 	 *	    hold a lock on the vnode).
2374 	 */
2375 	hammer2_inode_ref(ip);
2376 	if ((ip->flags & HAMMER2_INODE_MODIFIED) ||
2377 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
2378 		vfsync(vp, info->waitfor, 1, NULL, NULL);
2379 		if (ip->flags & (HAMMER2_INODE_RESIZED |
2380 				 HAMMER2_INODE_MODIFIED)) {
2381 			hammer2_inode_lock(ip, 0);
2382 			if (ip->flags & (HAMMER2_INODE_RESIZED |
2383 					 HAMMER2_INODE_MODIFIED)) {
2384 				hammer2_inode_chain_sync(ip);
2385 			}
2386 			hammer2_inode_unlock(ip);
2387 		}
2388 	}
2389 	if ((ip->flags & HAMMER2_INODE_MODIFIED) == 0 &&
2390 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
2391 		vclrisdirty(vp);
2392 	}
2393 
2394 	hammer2_inode_drop(ip);
2395 #if 1
2396 	error = 0;
2397 	if (error)
2398 		info->error = error;
2399 #endif
2400 	return(0);
2401 }
2402 
2403 static
2404 int
2405 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2406 {
2407 	hammer2_inode_t *ip;
2408 
2409 	KKASSERT(MAXFIDSZ >= 16);
2410 	ip = VTOI(vp);
2411 	fhp->fid_len = offsetof(struct fid, fid_data[16]);
2412 	fhp->fid_ext = 0;
2413 	((hammer2_tid_t *)fhp->fid_data)[0] = ip->meta.inum;
2414 	((hammer2_tid_t *)fhp->fid_data)[1] = 0;
2415 
2416 	return 0;
2417 }
2418 
2419 static
2420 int
2421 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2422 	       struct fid *fhp, struct vnode **vpp)
2423 {
2424 	hammer2_pfs_t *pmp;
2425 	hammer2_tid_t inum;
2426 	int error;
2427 
2428 	pmp = MPTOPMP(mp);
2429 	inum = ((hammer2_tid_t *)fhp->fid_data)[0] & HAMMER2_DIRHASH_USERMSK;
2430 	if (vpp) {
2431 		if (inum == 1)
2432 			error = hammer2_vfs_root(mp, vpp);
2433 		else
2434 			error = hammer2_vfs_vget(mp, NULL, inum, vpp);
2435 	} else {
2436 		error = 0;
2437 	}
2438 	if (error)
2439 		kprintf("fhtovp: %016jx -> %p, %d\n", inum, *vpp, error);
2440 	return error;
2441 }
2442 
2443 static
2444 int
2445 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2446 		 int *exflagsp, struct ucred **credanonp)
2447 {
2448 	hammer2_pfs_t *pmp;
2449 	struct netcred *np;
2450 	int error;
2451 
2452 	pmp = MPTOPMP(mp);
2453 	np = vfs_export_lookup(mp, &pmp->export, nam);
2454 	if (np) {
2455 		*exflagsp = np->netc_exflags;
2456 		*credanonp = &np->netc_anon;
2457 		error = 0;
2458 	} else {
2459 		error = EACCES;
2460 	}
2461 	return error;
2462 }
2463 
2464 /*
2465  * Support code for hammer2_vfs_mount().  Read, verify, and install the volume
2466  * header into the HMP
2467  *
2468  * XXX read four volhdrs and use the one with the highest TID whos CRC
2469  *     matches.
2470  *
2471  * XXX check iCRCs.
2472  *
2473  * XXX For filesystems w/ less than 4 volhdrs, make sure to not write to
2474  *     nonexistant locations.
2475  *
2476  * XXX Record selected volhdr and ring updates to each of 4 volhdrs
2477  */
2478 static
2479 int
2480 hammer2_install_volume_header(hammer2_dev_t *hmp)
2481 {
2482 	hammer2_volume_data_t *vd;
2483 	struct buf *bp;
2484 	hammer2_crc32_t crc0, crc, bcrc0, bcrc;
2485 	int error_reported;
2486 	int error;
2487 	int valid;
2488 	int i;
2489 
2490 	error_reported = 0;
2491 	error = 0;
2492 	valid = 0;
2493 	bp = NULL;
2494 
2495 	/*
2496 	 * There are up to 4 copies of the volume header (syncs iterate
2497 	 * between them so there is no single master).  We don't trust the
2498 	 * volu_size field so we don't know precisely how large the filesystem
2499 	 * is, so depend on the OS to return an error if we go beyond the
2500 	 * block device's EOF.
2501 	 */
2502 	for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
2503 		error = bread(hmp->devvp, i * HAMMER2_ZONE_BYTES64,
2504 			      HAMMER2_VOLUME_BYTES, &bp);
2505 		if (error) {
2506 			brelse(bp);
2507 			bp = NULL;
2508 			continue;
2509 		}
2510 
2511 		vd = (struct hammer2_volume_data *) bp->b_data;
2512 		if ((vd->magic != HAMMER2_VOLUME_ID_HBO) &&
2513 		    (vd->magic != HAMMER2_VOLUME_ID_ABO)) {
2514 			brelse(bp);
2515 			bp = NULL;
2516 			continue;
2517 		}
2518 
2519 		if (vd->magic == HAMMER2_VOLUME_ID_ABO) {
2520 			/* XXX: Reversed-endianness filesystem */
2521 			kprintf("hammer2: reverse-endian filesystem detected");
2522 			brelse(bp);
2523 			bp = NULL;
2524 			continue;
2525 		}
2526 
2527 		crc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT0];
2528 		crc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC0_OFF,
2529 				      HAMMER2_VOLUME_ICRC0_SIZE);
2530 		bcrc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT1];
2531 		bcrc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC1_OFF,
2532 				       HAMMER2_VOLUME_ICRC1_SIZE);
2533 		if ((crc0 != crc) || (bcrc0 != bcrc)) {
2534 			kprintf("hammer2 volume header crc "
2535 				"mismatch copy #%d %08x/%08x\n",
2536 				i, crc0, crc);
2537 			error_reported = 1;
2538 			brelse(bp);
2539 			bp = NULL;
2540 			continue;
2541 		}
2542 		if (valid == 0 || hmp->voldata.mirror_tid < vd->mirror_tid) {
2543 			valid = 1;
2544 			hmp->voldata = *vd;
2545 			hmp->volhdrno = i;
2546 		}
2547 		brelse(bp);
2548 		bp = NULL;
2549 	}
2550 	if (valid) {
2551 		hmp->volsync = hmp->voldata;
2552 		hmp->free_reserved = hmp->voldata.allocator_size / 20;
2553 		error = 0;
2554 		if (error_reported || bootverbose || 1) { /* 1/DEBUG */
2555 			kprintf("hammer2: using volume header #%d\n",
2556 				hmp->volhdrno);
2557 		}
2558 	} else {
2559 		error = EINVAL;
2560 		kprintf("hammer2: no valid volume headers found!\n");
2561 	}
2562 	return (error);
2563 }
2564 
2565 /*
2566  * This handles hysteresis on regular file flushes.  Because the BIOs are
2567  * routed to a thread it is possible for an excessive number to build up
2568  * and cause long front-end stalls long before the runningbuffspace limit
2569  * is hit, so we implement hammer2_flush_pipe to control the
2570  * hysteresis.
2571  *
2572  * This is a particular problem when compression is used.
2573  */
2574 void
2575 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
2576 {
2577 	atomic_add_int(&pmp->count_lwinprog, 1);
2578 }
2579 
2580 void
2581 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
2582 {
2583 	int lwinprog;
2584 
2585 	lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
2586 	if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
2587 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
2588 		atomic_clear_int(&pmp->count_lwinprog,
2589 				 HAMMER2_LWINPROG_WAITING);
2590 		wakeup(&pmp->count_lwinprog);
2591 	}
2592 	if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
2593 	    (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
2594 		atomic_clear_int(&pmp->count_lwinprog,
2595 				 HAMMER2_LWINPROG_WAITING0);
2596 		wakeup(&pmp->count_lwinprog);
2597 	}
2598 }
2599 
2600 void
2601 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
2602 {
2603 	int lwinprog;
2604 	int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
2605 				    HAMMER2_LWINPROG_WAITING0;
2606 
2607 	for (;;) {
2608 		lwinprog = pmp->count_lwinprog;
2609 		cpu_ccfence();
2610 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2611 			break;
2612 		tsleep_interlock(&pmp->count_lwinprog, 0);
2613 		atomic_set_int(&pmp->count_lwinprog, lwflag);
2614 		lwinprog = pmp->count_lwinprog;
2615 		if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2616 			break;
2617 		tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
2618 	}
2619 }
2620 
2621 /*
2622  * Manage excessive memory resource use for chain and related
2623  * structures.
2624  */
2625 void
2626 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
2627 {
2628 	uint32_t waiting;
2629 	uint32_t count;
2630 	uint32_t limit;
2631 #if 0
2632 	static int zzticks;
2633 #endif
2634 
2635 	/*
2636 	 * Atomic check condition and wait.  Also do an early speedup of
2637 	 * the syncer to try to avoid hitting the wait.
2638 	 */
2639 	for (;;) {
2640 		waiting = pmp->inmem_dirty_chains;
2641 		cpu_ccfence();
2642 		count = waiting & HAMMER2_DIRTYCHAIN_MASK;
2643 
2644 		limit = pmp->mp->mnt_nvnodelistsize / 10;
2645 		if (limit < hammer2_limit_dirty_chains)
2646 			limit = hammer2_limit_dirty_chains;
2647 		if (limit < 1000)
2648 			limit = 1000;
2649 
2650 #if 0
2651 		if ((int)(ticks - zzticks) > hz) {
2652 			zzticks = ticks;
2653 			kprintf("count %ld %ld\n", count, limit);
2654 		}
2655 #endif
2656 
2657 		/*
2658 		 * Block if there are too many dirty chains present, wait
2659 		 * for the flush to clean some out.
2660 		 */
2661 		if (count > limit) {
2662 			tsleep_interlock(&pmp->inmem_dirty_chains, 0);
2663 			if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2664 					       waiting,
2665 				       waiting | HAMMER2_DIRTYCHAIN_WAITING)) {
2666 				speedup_syncer(pmp->mp);
2667 				tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED,
2668 				       "chnmem", hz);
2669 			}
2670 			continue;	/* loop on success or fail */
2671 		}
2672 
2673 		/*
2674 		 * Try to start an early flush before we are forced to block.
2675 		 */
2676 		if (count > limit * 7 / 10)
2677 			speedup_syncer(pmp->mp);
2678 		break;
2679 	}
2680 }
2681 
2682 void
2683 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
2684 {
2685 	if (pmp) {
2686 		atomic_add_int(&pmp->inmem_dirty_chains, 1);
2687 	}
2688 }
2689 
2690 void
2691 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp)
2692 {
2693 	uint32_t waiting;
2694 
2695 	if (pmp == NULL)
2696 		return;
2697 
2698 	for (;;) {
2699 		waiting = pmp->inmem_dirty_chains;
2700 		cpu_ccfence();
2701 		if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2702 				       waiting,
2703 				       (waiting - 1) &
2704 					~HAMMER2_DIRTYCHAIN_WAITING)) {
2705 			break;
2706 		}
2707 	}
2708 
2709 	if (waiting & HAMMER2_DIRTYCHAIN_WAITING)
2710 		wakeup(&pmp->inmem_dirty_chains);
2711 }
2712 
2713 /*
2714  * Returns 0 if the filesystem has tons of free space
2715  * Returns 1 if the filesystem has less than 10% remaining
2716  * Returns 2 if the filesystem has less than 2%/5% (user/root) remaining.
2717  */
2718 int
2719 hammer2_vfs_enospace(hammer2_inode_t *ip, off_t bytes, struct ucred *cred)
2720 {
2721 	hammer2_pfs_t *pmp;
2722 	hammer2_dev_t *hmp;
2723 	hammer2_off_t free_reserved;
2724 	hammer2_off_t free_nominal;
2725 	int i;
2726 
2727 	pmp = ip->pmp;
2728 
2729 	if (pmp->free_ticks == 0 || pmp->free_ticks != ticks) {
2730 		free_reserved = HAMMER2_SEGSIZE;
2731 		free_nominal = 0x7FFFFFFFFFFFFFFFLLU;
2732 		for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
2733 			hmp = pmp->pfs_hmps[i];
2734 			if (hmp == NULL)
2735 				continue;
2736 			if (pmp->pfs_types[i] != HAMMER2_PFSTYPE_MASTER &&
2737 			    pmp->pfs_types[i] != HAMMER2_PFSTYPE_SOFT_MASTER)
2738 				continue;
2739 
2740 			if (free_nominal > hmp->voldata.allocator_free)
2741 				free_nominal = hmp->voldata.allocator_free;
2742 			if (free_reserved < hmp->free_reserved)
2743 				free_reserved = hmp->free_reserved;
2744 		}
2745 
2746 		/*
2747 		 * SMP races ok
2748 		 */
2749 		pmp->free_reserved = free_reserved;
2750 		pmp->free_nominal = free_nominal;
2751 		pmp->free_ticks = ticks;
2752 	} else {
2753 		free_reserved = pmp->free_reserved;
2754 		free_nominal = pmp->free_nominal;
2755 	}
2756 	if (cred && cred->cr_uid != 0) {
2757 		if ((int64_t)(free_nominal - bytes) <
2758 		    (int64_t)free_reserved) {
2759 			return 2;
2760 		}
2761 	} else {
2762 		if ((int64_t)(free_nominal - bytes) <
2763 		    (int64_t)free_reserved / 2) {
2764 			return 2;
2765 		}
2766 	}
2767 	if ((int64_t)(free_nominal - bytes) < (int64_t)free_reserved * 2)
2768 		return 1;
2769 	return 0;
2770 }
2771 
2772 /*
2773  * Debugging
2774  */
2775 void
2776 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int *countp, char pfx)
2777 {
2778 	hammer2_chain_t *scan;
2779 	hammer2_chain_t *parent;
2780 
2781 	--*countp;
2782 	if (*countp == 0) {
2783 		kprintf("%*.*s...\n", tab, tab, "");
2784 		return;
2785 	}
2786 	if (*countp < 0)
2787 		return;
2788 	kprintf("%*.*s%c-chain %p.%d %016jx/%d mir=%016jx\n",
2789 		tab, tab, "", pfx,
2790 		chain, chain->bref.type,
2791 		chain->bref.key, chain->bref.keybits,
2792 		chain->bref.mirror_tid);
2793 
2794 	kprintf("%*.*s      [%08x] (%s) refs=%d",
2795 		tab, tab, "",
2796 		chain->flags,
2797 		((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2798 		chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
2799 		chain->refs);
2800 
2801 	parent = chain->parent;
2802 	if (parent)
2803 		kprintf("\n%*.*s      p=%p [pflags %08x prefs %d",
2804 			tab, tab, "",
2805 			parent, parent->flags, parent->refs);
2806 	if (RB_EMPTY(&chain->core.rbtree)) {
2807 		kprintf("\n");
2808 	} else {
2809 		kprintf(" {\n");
2810 		RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree)
2811 			hammer2_dump_chain(scan, tab + 4, countp, 'a');
2812 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
2813 			kprintf("%*.*s}(%s)\n", tab, tab, "",
2814 				chain->data->ipdata.filename);
2815 		else
2816 			kprintf("%*.*s}\n", tab, tab, "");
2817 	}
2818 }
2819