sys/vfs/hammer2/hammer2_vfsops.c

   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 TAILQ_HEAD(hammer2_pfslist, hammer2_pfs);
  76 static struct hammer2_mntlist hammer2_mntlist;
  77 static struct hammer2_pfslist hammer2_pfslist;
  78 static struct lock hammer2_mntlk;
  79
  80 int hammer2_debug;
  81 int hammer2_cluster_enable = 1;
  82 int hammer2_hardlink_enable = 1;
  83 int hammer2_flush_pipe = 100;
  84 int hammer2_synchronous_flush = 1;
  85 int hammer2_dio_count;
  86 long hammer2_limit_dirty_chains;
  87 long hammer2_iod_file_read;
  88 long hammer2_iod_meta_read;
  89 long hammer2_iod_indr_read;
  90 long hammer2_iod_fmap_read;
  91 long hammer2_iod_volu_read;
  92 long hammer2_iod_file_write;
  93 long hammer2_iod_file_wembed;
  94 long hammer2_iod_file_wzero;
  95 long hammer2_iod_file_wdedup;
  96 long hammer2_iod_meta_write;
  97 long hammer2_iod_indr_write;
  98 long hammer2_iod_fmap_write;
  99 long hammer2_iod_volu_write;
 100 long hammer2_ioa_file_read;
 101 long hammer2_ioa_meta_read;
 102 long hammer2_ioa_indr_read;
 103 long hammer2_ioa_fmap_read;
 104 long hammer2_ioa_volu_read;
 105 long hammer2_ioa_fmap_write;
 106 long hammer2_ioa_file_write;
 107 long hammer2_ioa_meta_write;
 108 long hammer2_ioa_indr_write;
 109 long hammer2_ioa_volu_write;
 110
 111 MALLOC_DECLARE(M_HAMMER2_CBUFFER);
 112 MALLOC_DEFINE(M_HAMMER2_CBUFFER, "HAMMER2-compbuffer",
 113                 "Buffer used for compression.");
 114
 115 MALLOC_DECLARE(M_HAMMER2_DEBUFFER);
 116 MALLOC_DEFINE(M_HAMMER2_DEBUFFER, "HAMMER2-decompbuffer",
 117                 "Buffer used for decompression.");
 118
 119 SYSCTL_NODE(_vfs, OID_AUTO, hammer2, CTLFLAG_RW, 0, "HAMMER2 filesystem");
 120
 121 SYSCTL_INT(_vfs_hammer2, OID_AUTO, debug, CTLFLAG_RW,
 122            &hammer2_debug, 0, "");
 123 SYSCTL_INT(_vfs_hammer2, OID_AUTO, cluster_enable, CTLFLAG_RW,
 124            &hammer2_cluster_enable, 0, "");
 125 SYSCTL_INT(_vfs_hammer2, OID_AUTO, hardlink_enable, CTLFLAG_RW,
 126            &hammer2_hardlink_enable, 0, "");
 127 SYSCTL_INT(_vfs_hammer2, OID_AUTO, flush_pipe, CTLFLAG_RW,
 128            &hammer2_flush_pipe, 0, "");
 129 SYSCTL_INT(_vfs_hammer2, OID_AUTO, synchronous_flush, CTLFLAG_RW,
 130            &hammer2_synchronous_flush, 0, "");
 131 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, limit_dirty_chains, CTLFLAG_RW,
 132            &hammer2_limit_dirty_chains, 0, "");
 133 SYSCTL_INT(_vfs_hammer2, OID_AUTO, dio_count, CTLFLAG_RD,
 134            &hammer2_dio_count, 0, "");
 135
 136 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_read, CTLFLAG_RW,
 137            &hammer2_iod_file_read, 0, "");
 138 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_read, CTLFLAG_RW,
 139            &hammer2_iod_meta_read, 0, "");
 140 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_read, CTLFLAG_RW,
 141            &hammer2_iod_indr_read, 0, "");
 142 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_read, CTLFLAG_RW,
 143            &hammer2_iod_fmap_read, 0, "");
 144 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_read, CTLFLAG_RW,
 145            &hammer2_iod_volu_read, 0, "");
 146
 147 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_write, CTLFLAG_RW,
 148            &hammer2_iod_file_write, 0, "");
 149 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wembed, CTLFLAG_RW,
 150            &hammer2_iod_file_wembed, 0, "");
 151 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wzero, CTLFLAG_RW,
 152            &hammer2_iod_file_wzero, 0, "");
 153 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_file_wdedup, CTLFLAG_RW,
 154            &hammer2_iod_file_wdedup, 0, "");
 155 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_meta_write, CTLFLAG_RW,
 156            &hammer2_iod_meta_write, 0, "");
 157 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_indr_write, CTLFLAG_RW,
 158            &hammer2_iod_indr_write, 0, "");
 159 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_fmap_write, CTLFLAG_RW,
 160            &hammer2_iod_fmap_write, 0, "");
 161 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, iod_volu_write, CTLFLAG_RW,
 162            &hammer2_iod_volu_write, 0, "");
 163
 164 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_file_read, CTLFLAG_RW,
 165            &hammer2_ioa_file_read, 0, "");
 166 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_meta_read, CTLFLAG_RW,
 167            &hammer2_ioa_meta_read, 0, "");
 168 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_indr_read, CTLFLAG_RW,
 169            &hammer2_ioa_indr_read, 0, "");
 170 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_fmap_read, CTLFLAG_RW,
 171            &hammer2_ioa_fmap_read, 0, "");
 172 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_volu_read, CTLFLAG_RW,
 173            &hammer2_ioa_volu_read, 0, "");
 174
 175 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_file_write, CTLFLAG_RW,
 176            &hammer2_ioa_file_write, 0, "");
 177 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_meta_write, CTLFLAG_RW,
 178            &hammer2_ioa_meta_write, 0, "");
 179 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_indr_write, CTLFLAG_RW,
 180            &hammer2_ioa_indr_write, 0, "");
 181 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_fmap_write, CTLFLAG_RW,
 182            &hammer2_ioa_fmap_write, 0, "");
 183 SYSCTL_LONG(_vfs_hammer2, OID_AUTO, ioa_volu_write, CTLFLAG_RW,
 184            &hammer2_ioa_volu_write, 0, "");
 185
 186 static int hammer2_vfs_init(struct vfsconf *conf);
 187 static int hammer2_vfs_uninit(struct vfsconf *vfsp);
 188 static int hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
 189                                 struct ucred *cred);
 190 static int hammer2_remount(hammer2_dev_t *, struct mount *, char *,
 191                                 struct vnode *, struct ucred *);
 192 static int hammer2_recovery(hammer2_dev_t *hmp);
 193 static int hammer2_vfs_unmount(struct mount *mp, int mntflags);
 194 static int hammer2_vfs_root(struct mount *mp, struct vnode **vpp);
 195 static int hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp,
 196                                 struct ucred *cred);
 197 static int hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
 198                                 struct ucred *cred);
 199 static int hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
 200                                 ino_t ino, struct vnode **vpp);
 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, 0);
 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         if (HAMMER2_BLOCKREF_BYTES != sizeof(struct hammer2_blockref))
 252                 error = EINVAL;
 253         if (HAMMER2_INODE_BYTES != sizeof(struct hammer2_inode_data))
 254                 error = EINVAL;
 255         if (HAMMER2_VOLUME_BYTES != sizeof(struct hammer2_volume_data))
 256                 error = EINVAL;
 257
 258         if (error)
 259                 kprintf("HAMMER2 structure size mismatch; cannot continue.\n");
 260
 261         margs_read.objsize = 65536;
 262         margs_read.mtype = M_HAMMER2_DEBUFFER;
 263
 264         margs_write.objsize = 32768;
 265         margs_write.mtype = M_HAMMER2_CBUFFER;
 266
 267         margs_vop.objsize = sizeof(hammer2_xop_t);
 268         margs_vop.mtype = M_HAMMER2;
 269
 270         /*
 271          * Note thaht for the XOPS cache we want backing store allocations
 272          * to use M_ZERO.  This is not allowed in objcache_get() (to avoid
 273          * confusion), so use the backing store function that does it.  This
 274          * means that initial XOPS objects are zerod but REUSED objects are
 275          * not.  So we are responsible for cleaning the object up sufficiently
 276          * for our needs before objcache_put()ing it back (typically just the
 277          * FIFO indices).
 278          */
 279         cache_buffer_read = objcache_create(margs_read.mtype->ks_shortdesc,
 280                                 0, 1, NULL, NULL, NULL,
 281                                 objcache_malloc_alloc,
 282                                 objcache_malloc_free,
 283                                 &margs_read);
 284         cache_buffer_write = objcache_create(margs_write.mtype->ks_shortdesc,
 285                                 0, 1, NULL, NULL, NULL,
 286                                 objcache_malloc_alloc,
 287                                 objcache_malloc_free,
 288                                 &margs_write);
 289         cache_xops = objcache_create(margs_vop.mtype->ks_shortdesc,
 290                                 0, 1, NULL, NULL, NULL,
 291                                 objcache_malloc_alloc_zero,
 292                                 objcache_malloc_free,
 293                                 &margs_vop);
 294
 295
 296         lockinit(&hammer2_mntlk, "mntlk", 0, 0);
 297         TAILQ_INIT(&hammer2_mntlist);
 298         TAILQ_INIT(&hammer2_pfslist);
 299
 300         hammer2_limit_dirty_chains = desiredvnodes / 10;
 301
 302         return (error);
 303 }
 304
 305 static
 306 int
 307 hammer2_vfs_uninit(struct vfsconf *vfsp __unused)
 308 {
 309         objcache_destroy(cache_buffer_read);
 310         objcache_destroy(cache_buffer_write);
 311         objcache_destroy(cache_xops);
 312         return 0;
 313 }
 314
 315 /*
 316  * Core PFS allocator.  Used to allocate the pmp structure for PFS cluster
 317  * mounts and the spmp structure for media (hmp) structures.
 318  *
 319  * pmp->modify_tid tracks new modify_tid transaction ids for front-end
 320  * transactions.  Note that synchronization does not use this field.
 321  * (typically frontend operations and synchronization cannot run on the
 322  * same PFS node at the same time).
 323  *
 324  * XXX check locking
 325  */
 326 hammer2_pfs_t *
 327 hammer2_pfsalloc(hammer2_chain_t *chain, const hammer2_inode_data_t *ripdata,
 328                  hammer2_tid_t modify_tid)
 329 {
 330         hammer2_inode_t *iroot;
 331         hammer2_pfs_t *pmp;
 332         int count;
 333         int i;
 334         int j;
 335
 336         /*
 337          * Locate or create the PFS based on the cluster id.  If ripdata
 338          * is NULL this is a spmp which is unique and is always allocated.
 339          */
 340         if (ripdata) {
 341                 TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
 342                         if (bcmp(&pmp->pfs_clid, &ripdata->meta.pfs_clid,
 343                                  sizeof(pmp->pfs_clid)) == 0) {
 344                                         break;
 345                         }
 346                 }
 347         } else {
 348                 pmp = NULL;
 349         }
 350
 351         if (pmp == NULL) {
 352                 pmp = kmalloc(sizeof(*pmp), M_HAMMER2, M_WAITOK | M_ZERO);
 353                 hammer2_trans_manage_init(pmp);
 354                 kmalloc_create(&pmp->minode, "HAMMER2-inodes");
 355                 kmalloc_create(&pmp->mmsg, "HAMMER2-pfsmsg");
 356                 lockinit(&pmp->lock, "pfslk", 0, 0);
 357                 spin_init(&pmp->inum_spin, "hm2pfsalloc_inum");
 358                 spin_init(&pmp->xop_spin, "h2xop");
 359                 RB_INIT(&pmp->inum_tree);
 360                 TAILQ_INIT(&pmp->unlinkq);
 361                 spin_init(&pmp->list_spin, "hm2pfsalloc_list");
 362
 363                 /*
 364                  * Distribute backend operations to threads
 365                  */
 366                 for (j = 0; j < HAMMER2_MAXCLUSTER; ++j)
 367                         TAILQ_INIT(&pmp->xopq[j]);
 368                 for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
 369                         hammer2_xop_group_init(pmp, &pmp->xop_groups[j]);
 370
 371                 /*
 372                  * Save the last media transaction id for the flusher.  Set
 373                  * initial
 374                  */
 375                 if (ripdata)
 376                         pmp->pfs_clid = ripdata->meta.pfs_clid;
 377                 TAILQ_INSERT_TAIL(&hammer2_pfslist, pmp, mntentry);
 378
 379                 /*
 380                  * The synchronization thread may start too early, make
 381                  * sure it stays frozen until we are ready to let it go.
 382                  * XXX
 383                  */
 384                 /*
 385                 pmp->primary_thr.flags = HAMMER2_THREAD_FROZEN |
 386                                          HAMMER2_THREAD_REMASTER;
 387                 */
 388         }
 389
 390         /*
 391          * Create the PFS's root inode.
 392          */
 393         if ((iroot = pmp->iroot) == NULL) {
 394                 iroot = hammer2_inode_get(pmp, NULL, NULL, -1);
 395                 pmp->iroot = iroot;
 396                 hammer2_inode_ref(iroot);
 397                 hammer2_inode_unlock(iroot);
 398         }
 399
 400         /*
 401          * Stop here if no chain is passed in.
 402          */
 403         if (chain == NULL)
 404                 goto done;
 405
 406         /*
 407          * When a chain is passed in we must add it to the PFS's root
 408          * inode, update pmp->pfs_types[], and update the syncronization
 409          * threads.
 410          *
 411          * At the moment empty spots can develop due to removals or failures.
 412          * Ultimately we want to re-fill these spots but doing so might
 413          * confused running code. XXX
 414          */
 415         hammer2_inode_ref(iroot);
 416         hammer2_mtx_ex(&iroot->lock);
 417         j = iroot->cluster.nchains;
 418
 419         kprintf("add PFS to pmp %p[%d]\n", pmp, j);
 420
 421         if (j == HAMMER2_MAXCLUSTER) {
 422                 kprintf("hammer2_mount: cluster full!\n");
 423                 /* XXX fatal error? */
 424         } else {
 425                 KKASSERT(chain->pmp == NULL);
 426                 chain->pmp = pmp;
 427                 hammer2_chain_ref(chain);
 428                 iroot->cluster.array[j].chain = chain;
 429                 pmp->pfs_types[j] = ripdata->meta.pfs_type;
 430                 pmp->pfs_names[j] = kstrdup(ripdata->filename, M_HAMMER2);
 431                 pmp->pfs_hmps[j] = chain->hmp;
 432
 433                 /*
 434                  * If the PFS is already mounted we must account
 435                  * for the mount_count here.
 436                  */
 437                 if (pmp->mp)
 438                         ++chain->hmp->mount_count;
 439
 440                 /*
 441                  * May have to fixup dirty chain tracking.  Previous
 442                  * pmp was NULL so nothing to undo.
 443                  */
 444                 if (chain->flags & HAMMER2_CHAIN_MODIFIED)
 445                         hammer2_pfs_memory_inc(pmp);
 446                 ++j;
 447         }
 448         iroot->cluster.nchains = j;
 449
 450         /*
 451          * Update nmasters from any PFS inode which is part of the cluster.
 452          * It is possible that this will result in a value which is too
 453          * high.  MASTER PFSs are authoritative for pfs_nmasters and will
 454          * override this value later on.
 455          *
 456          * (This informs us of masters that might not currently be
 457          *  discoverable by this mount).
 458          */
 459         if (ripdata && pmp->pfs_nmasters < ripdata->meta.pfs_nmasters) {
 460                 pmp->pfs_nmasters = ripdata->meta.pfs_nmasters;
 461         }
 462
 463         /*
 464          * Count visible masters.  Masters are usually added with
 465          * ripdata->meta.pfs_nmasters set to 1.  This detects when there
 466          * are more (XXX and must update the master inodes).
 467          */
 468         count = 0;
 469         for (i = 0; i < iroot->cluster.nchains; ++i) {
 470                 if (pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER)
 471                         ++count;
 472         }
 473         if (pmp->pfs_nmasters < count)
 474                 pmp->pfs_nmasters = count;
 475
 476         /*
 477          * Create missing synchronization and support threads.
 478          *
 479          * Single-node masters (including snapshots) have nothing to
 480          * synchronize and do not require this thread.
 481          *
 482          * Multi-node masters or any number of soft masters, slaves, copy,
 483          * or other PFS types need the thread.
 484          *
 485          * Each thread is responsible for its particular cluster index.
 486          * We use independent threads so stalls or mismatches related to
 487          * any given target do not affect other targets.
 488          */
 489         for (i = 0; i < iroot->cluster.nchains; ++i) {
 490                 /*
 491                  * Single-node masters (including snapshots) have nothing
 492                  * to synchronize and will make direct xops support calls,
 493                  * thus they do not require this thread.
 494                  *
 495                  * Note that there can be thousands of snapshots.  We do not
 496                  * want to create thousands of threads.
 497                  */
 498                 if (pmp->pfs_nmasters <= 1 &&
 499                     pmp->pfs_types[i] == HAMMER2_PFSTYPE_MASTER) {
 500                         continue;
 501                 }
 502
 503                 /*
 504                  * Sync support thread
 505                  */
 506                 if (pmp->sync_thrs[i].td == NULL) {
 507                         hammer2_thr_create(&pmp->sync_thrs[i], pmp,
 508                                            "h2nod", i, -1,
 509                                            hammer2_primary_sync_thread);
 510                 }
 511         }
 512
 513         /*
 514          * Create missing Xop threads
 515          */
 516         if (pmp->mp)
 517                 hammer2_xop_helper_create(pmp);
 518
 519         hammer2_mtx_unlock(&iroot->lock);
 520         hammer2_inode_drop(iroot);
 521 done:
 522         return pmp;
 523 }
 524
 525 /*
 526  * Destroy a PFS, typically only occurs after the last mount on a device
 527  * has gone away.
 528  */
 529 static void
 530 hammer2_pfsfree(hammer2_pfs_t *pmp)
 531 {
 532         hammer2_inode_t *iroot;
 533         int i;
 534         int j;
 535
 536         /*
 537          * Cleanup our reference on iroot.  iroot is (should) not be needed
 538          * by the flush code.
 539          */
 540         TAILQ_REMOVE(&hammer2_pfslist, pmp, mntentry);
 541
 542         iroot = pmp->iroot;
 543         if (iroot) {
 544                 for (i = 0; i < iroot->cluster.nchains; ++i) {
 545                         hammer2_thr_delete(&pmp->sync_thrs[i]);
 546                         for (j = 0; j < HAMMER2_XOPGROUPS; ++j)
 547                                 hammer2_thr_delete(&pmp->xop_groups[j].thrs[i]);
 548                 }
 549 #if REPORT_REFS_ERRORS
 550                 if (pmp->iroot->refs != 1)
 551                         kprintf("PMP->IROOT %p REFS WRONG %d\n",
 552                                 pmp->iroot, pmp->iroot->refs);
 553 #else
 554                 KKASSERT(pmp->iroot->refs == 1);
 555 #endif
 556                 /* ref for pmp->iroot */
 557                 hammer2_inode_drop(pmp->iroot);
 558                 pmp->iroot = NULL;
 559         }
 560
 561         kmalloc_destroy(&pmp->mmsg);
 562         kmalloc_destroy(&pmp->minode);
 563
 564         kfree(pmp, M_HAMMER2);
 565 }
 566
 567 /*
 568  * Remove all references to hmp from the pfs list.  Any PFS which becomes
 569  * empty is terminated and freed.
 570  *
 571  * XXX inefficient.
 572  */
 573 static void
 574 hammer2_pfsfree_scan(hammer2_dev_t *hmp)
 575 {
 576         hammer2_pfs_t *pmp;
 577         hammer2_inode_t *iroot;
 578         hammer2_chain_t *rchain;
 579         int didfreeze;
 580         int i;
 581         int j;
 582
 583 again:
 584         TAILQ_FOREACH(pmp, &hammer2_pfslist, mntentry) {
 585                 if ((iroot = pmp->iroot) == NULL)
 586                         continue;
 587                 if (hmp->spmp == pmp) {
 588                         kprintf("unmount hmp %p remove spmp %p\n",
 589                                 hmp, pmp);
 590                         hmp->spmp = NULL;
 591                 }
 592
 593                 /*
 594                  * Determine if this PFS is affected.  If it is we must
 595                  * freeze all management threads and lock its iroot.
 596                  *
 597                  * Freezing a management thread forces it idle, operations
 598                  * in-progress will be aborted and it will have to start
 599                  * over again when unfrozen, or exit if told to exit.
 600                  */
 601                 for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
 602                         if (pmp->pfs_hmps[i] == hmp)
 603                                 break;
 604                 }
 605                 if (i != HAMMER2_MAXCLUSTER) {
 606                         /*
 607                          * Make sure all synchronization threads are locked
 608                          * down.
 609                          */
 610                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
 611                                 if (pmp->pfs_hmps[i] == NULL)
 612                                         continue;
 613                                 hammer2_thr_freeze_async(&pmp->sync_thrs[i]);
 614                                 for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
 615                                         hammer2_thr_freeze_async(
 616                                                 &pmp->xop_groups[j].thrs[i]);
 617                                 }
 618                         }
 619                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
 620                                 if (pmp->pfs_hmps[i] == NULL)
 621                                         continue;
 622                                 hammer2_thr_freeze(&pmp->sync_thrs[i]);
 623                                 for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
 624                                         hammer2_thr_freeze(
 625                                                 &pmp->xop_groups[j].thrs[i]);
 626                                 }
 627                         }
 628
 629                         /*
 630                          * Lock the inode and clean out matching chains.
 631                          * Note that we cannot use hammer2_inode_lock_*()
 632                          * here because that would attempt to validate the
 633                          * cluster that we are in the middle of ripping
 634                          * apart.
 635                          *
 636                          * WARNING! We are working directly on the inodes
 637                          *          embedded cluster.
 638                          */
 639                         hammer2_mtx_ex(&iroot->lock);
 640
 641                         /*
 642                          * Remove the chain from matching elements of the PFS.
 643                          */
 644                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
 645                                 if (pmp->pfs_hmps[i] != hmp)
 646                                         continue;
 647                                 hammer2_thr_delete(&pmp->sync_thrs[i]);
 648                                 for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
 649                                         hammer2_thr_delete(
 650                                                 &pmp->xop_groups[j].thrs[i]);
 651                                 }
 652                                 rchain = iroot->cluster.array[i].chain;
 653                                 iroot->cluster.array[i].chain = NULL;
 654                                 pmp->pfs_types[i] = 0;
 655                                 if (pmp->pfs_names[i]) {
 656                                         kfree(pmp->pfs_names[i], M_HAMMER2);
 657                                         pmp->pfs_names[i] = NULL;
 658                                 }
 659                                 if (rchain) {
 660                                         hammer2_chain_drop(rchain);
 661                                         /* focus hint */
 662                                         if (iroot->cluster.focus == rchain)
 663                                                 iroot->cluster.focus = NULL;
 664                                 }
 665                                 pmp->pfs_hmps[i] = NULL;
 666                         }
 667                         hammer2_mtx_unlock(&iroot->lock);
 668                         didfreeze = 1;  /* remaster, unfreeze down below */
 669                 } else {
 670                         didfreeze = 0;
 671                 }
 672
 673                 /*
 674                  * Cleanup trailing chains.  Gaps may remain.
 675                  */
 676                 for (i = HAMMER2_MAXCLUSTER - 1; i >= 0; --i) {
 677                         if (pmp->pfs_hmps[i])
 678                                 break;
 679                 }
 680                 iroot->cluster.nchains = i + 1;
 681
 682                 /*
 683                  * If the PMP has no elements remaining we can destroy it.
 684                  * (this will transition management threads from frozen->exit).
 685                  */
 686                 if (iroot->cluster.nchains == 0) {
 687                         kprintf("unmount hmp %p last ref to PMP=%p\n",
 688                                 hmp, pmp);
 689                         hammer2_pfsfree(pmp);
 690                         goto again;
 691                 }
 692
 693                 /*
 694                  * If elements still remain we need to set the REMASTER
 695                  * flag and unfreeze it.
 696                  */
 697                 if (didfreeze) {
 698                         for (i = 0; i < HAMMER2_MAXCLUSTER; ++i) {
 699                                 if (pmp->pfs_hmps[i] == NULL)
 700                                         continue;
 701                                 hammer2_thr_remaster(&pmp->sync_thrs[i]);
 702                                 hammer2_thr_unfreeze(&pmp->sync_thrs[i]);
 703                                 for (j = 0; j < HAMMER2_XOPGROUPS; ++j) {
 704                                         hammer2_thr_remaster(
 705                                                 &pmp->xop_groups[j].thrs[i]);
 706                                         hammer2_thr_unfreeze(
 707                                                 &pmp->xop_groups[j].thrs[i]);
 708                                 }
 709                         }
 710                 }
 711         }
 712 }
 713
 714 /*
 715  * Mount or remount HAMMER2 fileystem from physical media
 716  *
 717  *      mountroot
 718  *              mp              mount point structure
 719  *              path            NULL
 720  *              data            <unused>
 721  *              cred            <unused>
 722  *
 723  *      mount
 724  *              mp              mount point structure
 725  *              path            path to mount point
 726  *              data            pointer to argument structure in user space
 727  *                      volume  volume path (device@LABEL form)
 728  *                      hflags  user mount flags
 729  *              cred            user credentials
 730  *
 731  * RETURNS:     0       Success
 732  *              !0      error number
 733  */
 734 static
 735 int
 736 hammer2_vfs_mount(struct mount *mp, char *path, caddr_t data,
 737                   struct ucred *cred)
 738 {
 739         struct hammer2_mount_info info;
 740         hammer2_pfs_t *pmp;
 741         hammer2_pfs_t *spmp;
 742         hammer2_dev_t *hmp;
 743         hammer2_key_t key_next;
 744         hammer2_key_t key_dummy;
 745         hammer2_key_t lhc;
 746         struct vnode *devvp;
 747         struct nlookupdata nd;
 748         hammer2_chain_t *parent;
 749         hammer2_chain_t *chain;
 750         hammer2_cluster_t *cluster;
 751         const hammer2_inode_data_t *ripdata;
 752         hammer2_blockref_t bref;
 753         struct file *fp;
 754         char devstr[MNAMELEN];
 755         size_t size;
 756         size_t done;
 757         char *dev;
 758         char *label;
 759         int ronly = 1;
 760         int error;
 761         int cache_index;
 762         int i;
 763
 764         hmp = NULL;
 765         pmp = NULL;
 766         dev = NULL;
 767         label = NULL;
 768         devvp = NULL;
 769         cache_index = -1;
 770
 771         kprintf("hammer2_mount\n");
 772
 773         if (path == NULL) {
 774                 /*
 775                  * Root mount
 776                  */
 777                 bzero(&info, sizeof(info));
 778                 info.cluster_fd = -1;
 779                 ksnprintf(devstr, sizeof(devstr), "%s",
 780                           mp->mnt_stat.f_mntfromname);
 781                 kprintf("hammer2_mount: root '%s'\n", devstr);
 782         } else {
 783                 /*
 784                  * Non-root mount or updating a mount
 785                  */
 786                 error = copyin(data, &info, sizeof(info));
 787                 if (error)
 788                         return (error);
 789
 790                 error = copyinstr(info.volume, devstr, MNAMELEN - 1, &done);
 791                 if (error)
 792                         return (error);
 793         }
 794
 795         /* Extract device and label */
 796         dev = devstr;
 797         label = strchr(devstr, '@');
 798         if (label == NULL ||
 799             ((label + 1) - dev) > done) {
 800                 return (EINVAL);
 801         }
 802         *label = '\0';
 803         label++;
 804         if (*label == '\0')
 805                 return (EINVAL);
 806
 807         if (mp->mnt_flag & MNT_UPDATE) {
 808                 /*
 809                  * Update mount.  Note that pmp->iroot->cluster is
 810                  * an inode-embedded cluster and thus cannot be
 811                  * directly locked.
 812                  *
 813                  * XXX HAMMER2 needs to implement NFS export via
 814                  *     mountctl.
 815                  */
 816                 pmp = MPTOPMP(mp);
 817                 cluster = &pmp->iroot->cluster;
 818                 for (i = 0; i < cluster->nchains; ++i) {
 819                         if (cluster->array[i].chain == NULL)
 820                                 continue;
 821                         hmp = cluster->array[i].chain->hmp;
 822                         devvp = hmp->devvp;
 823                         error = hammer2_remount(hmp, mp, path,
 824                                                 devvp, cred);
 825                         if (error)
 826                                 break;
 827                 }
 828
 829                 return error;
 830         }
 831
 832         /*
 833          * HMP device mount
 834          *
 835          * Lookup name and verify it refers to a block device.
 836          */
 837         if (path) {
 838                 error = nlookup_init(&nd, dev, UIO_SYSSPACE, NLC_FOLLOW);
 839                 if (error == 0)
 840                         error = nlookup(&nd);
 841                 if (error == 0)
 842                         error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
 843                 nlookup_done(&nd);
 844         } else {
 845                 /* root mount */
 846                 cdev_t cdev = kgetdiskbyname(dev);
 847                 error = bdevvp(cdev, &devvp);
 848                 if (error)
 849                         kprintf("hammer2: cannot find '%s'\n", dev);
 850         }
 851
 852         if (error == 0) {
 853                 if (vn_isdisk(devvp, &error))
 854                         error = vfs_mountedon(devvp);
 855         }
 856
 857         /*
 858          * Determine if the device has already been mounted.  After this
 859          * check hmp will be non-NULL if we are doing the second or more
 860          * hammer2 mounts from the same device.
 861          */
 862         lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
 863         TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
 864                 if (hmp->devvp == devvp)
 865                         break;
 866         }
 867
 868         /*
 869          * Open the device if this isn't a secondary mount and construct
 870          * the H2 device mount (hmp).
 871          */
 872         if (hmp == NULL) {
 873                 hammer2_chain_t *schain;
 874                 hammer2_xid_t xid;
 875
 876                 if (error == 0 && vcount(devvp) > 0)
 877                         error = EBUSY;
 878
 879                 /*
 880                  * Now open the device
 881                  */
 882                 if (error == 0) {
 883                         ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);
 884                         vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
 885                         error = vinvalbuf(devvp, V_SAVE, 0, 0);
 886                         if (error == 0) {
 887                                 error = VOP_OPEN(devvp,
 888                                                  ronly ? FREAD : FREAD | FWRITE,
 889                                                  FSCRED, NULL);
 890                         }
 891                         vn_unlock(devvp);
 892                 }
 893                 if (error && devvp) {
 894                         vrele(devvp);
 895                         devvp = NULL;
 896                 }
 897                 if (error) {
 898                         lockmgr(&hammer2_mntlk, LK_RELEASE);
 899                         return error;
 900                 }
 901                 hmp = kmalloc(sizeof(*hmp), M_HAMMER2, M_WAITOK | M_ZERO);
 902                 ksnprintf(hmp->devrepname, sizeof(hmp->devrepname), "%s", dev);
 903                 hmp->ronly = ronly;
 904                 hmp->devvp = devvp;
 905                 kmalloc_create(&hmp->mchain, "HAMMER2-chains");
 906                 TAILQ_INSERT_TAIL(&hammer2_mntlist, hmp, mntentry);
 907                 RB_INIT(&hmp->iotree);
 908                 spin_init(&hmp->io_spin, "hm2mount_io");
 909                 spin_init(&hmp->list_spin, "hm2mount_list");
 910                 TAILQ_INIT(&hmp->flushq);
 911
 912                 lockinit(&hmp->vollk, "h2vol", 0, 0);
 913                 lockinit(&hmp->bulklk, "h2bulk", 0, 0);
 914
 915                 /*
 916                  * vchain setup. vchain.data is embedded.
 917                  * vchain.refs is initialized and will never drop to 0.
 918                  *
 919                  * NOTE! voldata is not yet loaded.
 920                  */
 921                 hmp->vchain.hmp = hmp;
 922                 hmp->vchain.refs = 1;
 923                 hmp->vchain.data = (void *)&hmp->voldata;
 924                 hmp->vchain.bref.type = HAMMER2_BREF_TYPE_VOLUME;
 925                 hmp->vchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
 926                 hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
 927
 928                 hammer2_chain_core_init(&hmp->vchain);
 929                 /* hmp->vchain.u.xxx is left NULL */
 930
 931                 /*
 932                  * fchain setup.  fchain.data is embedded.
 933                  * fchain.refs is initialized and will never drop to 0.
 934                  *
 935                  * The data is not used but needs to be initialized to
 936                  * pass assertion muster.  We use this chain primarily
 937                  * as a placeholder for the freemap's top-level RBTREE
 938                  * so it does not interfere with the volume's topology
 939                  * RBTREE.
 940                  */
 941                 hmp->fchain.hmp = hmp;
 942                 hmp->fchain.refs = 1;
 943                 hmp->fchain.data = (void *)&hmp->voldata.freemap_blockset;
 944                 hmp->fchain.bref.type = HAMMER2_BREF_TYPE_FREEMAP;
 945                 hmp->fchain.bref.data_off = 0 | HAMMER2_PBUFRADIX;
 946                 hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
 947                 hmp->fchain.bref.methods =
 948                         HAMMER2_ENC_CHECK(HAMMER2_CHECK_FREEMAP) |
 949                         HAMMER2_ENC_COMP(HAMMER2_COMP_NONE);
 950
 951                 hammer2_chain_core_init(&hmp->fchain);
 952                 /* hmp->fchain.u.xxx is left NULL */
 953
 954                 /*
 955                  * Install the volume header and initialize fields from
 956                  * voldata.
 957                  */
 958                 error = hammer2_install_volume_header(hmp);
 959                 if (error) {
 960                         hammer2_unmount_helper(mp, NULL, hmp);
 961                         lockmgr(&hammer2_mntlk, LK_RELEASE);
 962                         hammer2_vfs_unmount(mp, MNT_FORCE);
 963                         return error;
 964                 }
 965
 966                 /*
 967                  * Really important to get these right or flush will get
 968                  * confused.
 969                  */
 970                 hmp->spmp = hammer2_pfsalloc(NULL, NULL, 0);
 971                 kprintf("alloc spmp %p tid %016jx\n",
 972                         hmp->spmp, hmp->voldata.mirror_tid);
 973                 spmp = hmp->spmp;
 974
 975                 /*
 976                  * Dummy-up vchain and fchain's modify_tid.  mirror_tid
 977                  * is inherited from the volume header.
 978                  */
 979                 xid = 0;
 980                 hmp->vchain.bref.mirror_tid = hmp->voldata.mirror_tid;
 981                 hmp->vchain.bref.modify_tid = hmp->vchain.bref.mirror_tid;
 982                 hmp->vchain.pmp = spmp;
 983                 hmp->fchain.bref.mirror_tid = hmp->voldata.freemap_tid;
 984                 hmp->fchain.bref.modify_tid = hmp->fchain.bref.mirror_tid;
 985                 hmp->fchain.pmp = spmp;
 986
 987                 /*
 988                  * First locate the super-root inode, which is key 0
 989                  * relative to the volume header's blockset.
 990                  *
 991                  * Then locate the root inode by scanning the directory keyspace
 992                  * represented by the label.
 993                  */
 994                 parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
 995                 schain = hammer2_chain_lookup(&parent, &key_dummy,
 996                                       HAMMER2_SROOT_KEY, HAMMER2_SROOT_KEY,
 997                                       &cache_index, 0);
 998                 hammer2_chain_lookup_done(parent);
 999                 if (schain == NULL) {
1000                         kprintf("hammer2_mount: invalid super-root\n");
1001                         hammer2_unmount_helper(mp, NULL, hmp);
1002                         lockmgr(&hammer2_mntlk, LK_RELEASE);
1003                         hammer2_vfs_unmount(mp, MNT_FORCE);
1004                         return EINVAL;
1005                 }
1006                 if (schain->error) {
1007                         kprintf("hammer2_mount: error %s reading super-root\n",
1008                                 hammer2_error_str(schain->error));
1009                         hammer2_chain_unlock(schain);
1010                         hammer2_chain_drop(schain);
1011                         schain = NULL;
1012                         hammer2_unmount_helper(mp, NULL, hmp);
1013                         lockmgr(&hammer2_mntlk, LK_RELEASE);
1014                         hammer2_vfs_unmount(mp, MNT_FORCE);
1015                         return EINVAL;
1016                 }
1017
1018                 /*
1019                  * The super-root always uses an inode_tid of 1 when
1020                  * creating PFSs.
1021                  */
1022                 spmp->inode_tid = 1;
1023                 spmp->modify_tid = schain->bref.modify_tid + 1;
1024
1025                 /*
1026                  * Sanity-check schain's pmp and finish initialization.
1027                  * Any chain belonging to the super-root topology should
1028                  * have a NULL pmp (not even set to spmp).
1029                  */
1030                 ripdata = &hammer2_chain_rdata(schain)->ipdata;
1031                 KKASSERT(schain->pmp == NULL);
1032                 spmp->pfs_clid = ripdata->meta.pfs_clid;
1033
1034                 /*
1035                  * Replace the dummy spmp->iroot with a real one.  It's
1036                  * easier to just do a wholesale replacement than to try
1037                  * to update the chain and fixup the iroot fields.
1038                  *
1039                  * The returned inode is locked with the supplied cluster.
1040                  */
1041                 cluster = hammer2_cluster_from_chain(schain);
1042                 hammer2_inode_drop(spmp->iroot);
1043                 spmp->iroot = NULL;
1044                 spmp->iroot = hammer2_inode_get(spmp, NULL, cluster, -1);
1045                 spmp->spmp_hmp = hmp;
1046                 spmp->pfs_types[0] = ripdata->meta.pfs_type;
1047                 spmp->pfs_hmps[0] = hmp;
1048                 hammer2_inode_ref(spmp->iroot);
1049                 hammer2_inode_unlock(spmp->iroot);
1050                 hammer2_cluster_unlock(cluster);
1051                 hammer2_cluster_drop(cluster);
1052                 schain = NULL;
1053                 /* leave spmp->iroot with one ref */
1054
1055                 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
1056                         error = hammer2_recovery(hmp);
1057                         /* XXX do something with error */
1058                 }
1059                 hammer2_update_pmps(hmp);
1060                 hammer2_iocom_init(hmp);
1061
1062                 /*
1063                  * Ref the cluster management messaging descriptor.  The mount
1064                  * program deals with the other end of the communications pipe.
1065                  *
1066                  * Root mounts typically do not supply one.
1067                  */
1068                 if (info.cluster_fd >= 0) {
1069                         fp = holdfp(curproc->p_fd, info.cluster_fd, -1);
1070                         if (fp) {
1071                                 hammer2_cluster_reconnect(hmp, fp);
1072                         } else {
1073                                 kprintf("hammer2_mount: bad cluster_fd!\n");
1074                         }
1075                 }
1076         } else {
1077                 spmp = hmp->spmp;
1078         }
1079
1080         /*
1081          * Lookup the mount point under the media-localized super-root.
1082          * Scanning hammer2_pfslist doesn't help us because it represents
1083          * PFS cluster ids which can aggregate several named PFSs together.
1084          *
1085          * cluster->pmp will incorrectly point to spmp and must be fixed
1086          * up later on.
1087          */
1088         hammer2_inode_lock(spmp->iroot, 0);
1089         parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1090         lhc = hammer2_dirhash(label, strlen(label));
1091         chain = hammer2_chain_lookup(&parent, &key_next,
1092                                      lhc, lhc + HAMMER2_DIRHASH_LOMASK,
1093                                      &cache_index, 0);
1094         while (chain) {
1095                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
1096                     strcmp(label, chain->data->ipdata.filename) == 0) {
1097                         break;
1098                 }
1099                 chain = hammer2_chain_next(&parent, chain, &key_next,
1100                                             key_next,
1101                                             lhc + HAMMER2_DIRHASH_LOMASK,
1102                                             &cache_index, 0);
1103         }
1104         if (parent) {
1105                 hammer2_chain_unlock(parent);
1106                 hammer2_chain_drop(parent);
1107         }
1108         hammer2_inode_unlock(spmp->iroot);
1109
1110         /*
1111          * PFS could not be found?
1112          */
1113         if (chain == NULL) {
1114                 kprintf("hammer2_mount: PFS label not found\n");
1115                 hammer2_unmount_helper(mp, NULL, hmp);
1116                 lockmgr(&hammer2_mntlk, LK_RELEASE);
1117                 hammer2_vfs_unmount(mp, MNT_FORCE);
1118
1119                 return EINVAL;
1120         }
1121
1122         /*
1123          * Acquire the pmp structure (it should have already been allocated
1124          * via hammer2_update_pmps() so do not pass cluster in to add to
1125          * available chains).
1126          *
1127          * Check if the cluster has already been mounted.  A cluster can
1128          * only be mounted once, use null mounts to mount additional copies.
1129          */
1130         ripdata = &chain->data->ipdata;
1131         bref = chain->bref;
1132         pmp = hammer2_pfsalloc(NULL, ripdata, bref.modify_tid);
1133         hammer2_chain_unlock(chain);
1134         hammer2_chain_drop(chain);
1135
1136         if (pmp->mp) {
1137                 kprintf("hammer2_mount: PFS already mounted!\n");
1138                 hammer2_unmount_helper(mp, NULL, hmp);
1139                 lockmgr(&hammer2_mntlk, LK_RELEASE);
1140                 hammer2_vfs_unmount(mp, MNT_FORCE);
1141
1142                 return EBUSY;
1143         }
1144
1145         /*
1146          * Finish the mount
1147          */
1148         kprintf("hammer2_mount hmp=%p pmp=%p\n", hmp, pmp);
1149
1150         mp->mnt_flag = MNT_LOCAL;
1151         mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;   /* all entry pts are SMP */
1152         mp->mnt_kern_flag |= MNTK_THR_SYNC;     /* new vsyncscan semantics */
1153
1154         /*
1155          * required mount structure initializations
1156          */
1157         mp->mnt_stat.f_iosize = HAMMER2_PBUFSIZE;
1158         mp->mnt_stat.f_bsize = HAMMER2_PBUFSIZE;
1159
1160         mp->mnt_vstat.f_frsize = HAMMER2_PBUFSIZE;
1161         mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1162
1163         /*
1164          * Optional fields
1165          */
1166         mp->mnt_iosize_max = MAXPHYS;
1167
1168         /*
1169          * Connect up mount pointers.
1170          */
1171         hammer2_mount_helper(mp, pmp);
1172
1173         lockmgr(&hammer2_mntlk, LK_RELEASE);
1174
1175         /*
1176          * Finish setup
1177          */
1178         vfs_getnewfsid(mp);
1179         vfs_add_vnodeops(mp, &hammer2_vnode_vops, &mp->mnt_vn_norm_ops);
1180         vfs_add_vnodeops(mp, &hammer2_spec_vops, &mp->mnt_vn_spec_ops);
1181         vfs_add_vnodeops(mp, &hammer2_fifo_vops, &mp->mnt_vn_fifo_ops);
1182
1183         if (path) {
1184                 copyinstr(info.volume, mp->mnt_stat.f_mntfromname,
1185                           MNAMELEN - 1, &size);
1186                 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
1187         } /* else root mount, already in there */
1188
1189         bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
1190         if (path) {
1191                 copyinstr(path, mp->mnt_stat.f_mntonname,
1192                           sizeof(mp->mnt_stat.f_mntonname) - 1,
1193                           &size);
1194         } else {
1195                 /* root mount */
1196                 mp->mnt_stat.f_mntonname[0] = '/';
1197         }
1198
1199         /*
1200          * Initial statfs to prime mnt_stat.
1201          */
1202         hammer2_vfs_statfs(mp, &mp->mnt_stat, cred);
1203
1204         return 0;
1205 }
1206
1207 /*
1208  * Scan PFSs under the super-root and create hammer2_pfs structures.
1209  */
1210 static
1211 void
1212 hammer2_update_pmps(hammer2_dev_t *hmp)
1213 {
1214         const hammer2_inode_data_t *ripdata;
1215         hammer2_chain_t *parent;
1216         hammer2_chain_t *chain;
1217         hammer2_blockref_t bref;
1218         hammer2_pfs_t *spmp;
1219         hammer2_pfs_t *pmp;
1220         hammer2_key_t key_next;
1221         int cache_index = -1;
1222
1223         /*
1224          * Lookup mount point under the media-localized super-root.
1225          *
1226          * cluster->pmp will incorrectly point to spmp and must be fixed
1227          * up later on.
1228          */
1229         spmp = hmp->spmp;
1230         hammer2_inode_lock(spmp->iroot, 0);
1231         parent = hammer2_inode_chain(spmp->iroot, 0, HAMMER2_RESOLVE_ALWAYS);
1232         chain = hammer2_chain_lookup(&parent, &key_next,
1233                                          HAMMER2_KEY_MIN, HAMMER2_KEY_MAX,
1234                                          &cache_index, 0);
1235         while (chain) {
1236                 if (chain->bref.type != HAMMER2_BREF_TYPE_INODE)
1237                         continue;
1238                 ripdata = &chain->data->ipdata;
1239                 bref = chain->bref;
1240                 kprintf("ADD LOCAL PFS: %s\n", ripdata->filename);
1241
1242                 pmp = hammer2_pfsalloc(chain, ripdata, bref.modify_tid);
1243                 chain = hammer2_chain_next(&parent, chain, &key_next,
1244                                            key_next, HAMMER2_KEY_MAX,
1245                                            &cache_index, 0);
1246         }
1247         if (parent) {
1248                 hammer2_chain_unlock(parent);
1249                 hammer2_chain_drop(parent);
1250         }
1251         hammer2_inode_unlock(spmp->iroot);
1252 }
1253
1254 static
1255 int
1256 hammer2_remount(hammer2_dev_t *hmp, struct mount *mp, char *path __unused,
1257                 struct vnode *devvp, struct ucred *cred)
1258 {
1259         int error;
1260
1261         if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
1262                 error = hammer2_recovery(hmp);
1263         } else {
1264                 error = 0;
1265         }
1266         return error;
1267 }
1268
1269 static
1270 int
1271 hammer2_vfs_unmount(struct mount *mp, int mntflags)
1272 {
1273         hammer2_pfs_t *pmp;
1274         int flags;
1275         int error = 0;
1276
1277         pmp = MPTOPMP(mp);
1278
1279         if (pmp == NULL)
1280                 return(0);
1281
1282         lockmgr(&hammer2_mntlk, LK_EXCLUSIVE);
1283
1284         /*
1285          * If mount initialization proceeded far enough we must flush
1286          * its vnodes and sync the underlying mount points.  Three syncs
1287          * are required to fully flush the filesystem (freemap updates lag
1288          * by one flush, and one extra for safety).
1289          */
1290         if (mntflags & MNT_FORCE)
1291                 flags = FORCECLOSE;
1292         else
1293                 flags = 0;
1294         if (pmp->iroot) {
1295                 error = vflush(mp, 0, flags);
1296                 if (error)
1297                         goto failed;
1298                 hammer2_vfs_sync(mp, MNT_WAIT);
1299                 hammer2_vfs_sync(mp, MNT_WAIT);
1300                 hammer2_vfs_sync(mp, MNT_WAIT);
1301         }
1302
1303         /*
1304          * Cleanup the frontend support XOPS threads
1305          */
1306         hammer2_xop_helper_cleanup(pmp);
1307
1308         /*
1309          * Cleanup our reference on ihidden.
1310          */
1311         if (pmp->ihidden) {
1312                 hammer2_inode_drop(pmp->ihidden);
1313                 pmp->ihidden = NULL;
1314         }
1315         if (pmp->mp)
1316                 hammer2_unmount_helper(mp, pmp, NULL);
1317
1318         error = 0;
1319 failed:
1320         lockmgr(&hammer2_mntlk, LK_RELEASE);
1321
1322         return (error);
1323 }
1324
1325 /*
1326  * Mount helper, hook the system mount into our PFS.
1327  * The mount lock is held.
1328  *
1329  * We must bump the mount_count on related devices for any
1330  * mounted PFSs.
1331  */
1332 static
1333 void
1334 hammer2_mount_helper(struct mount *mp, hammer2_pfs_t *pmp)
1335 {
1336         hammer2_cluster_t *cluster;
1337         hammer2_chain_t *rchain;
1338         int i;
1339
1340         mp->mnt_data = (qaddr_t)pmp;
1341         pmp->mp = mp;
1342
1343         /*
1344          * After pmp->mp is set we have to adjust hmp->mount_count.
1345          */
1346         cluster = &pmp->iroot->cluster;
1347         for (i = 0; i < cluster->nchains; ++i) {
1348                 rchain = cluster->array[i].chain;
1349                 if (rchain == NULL)
1350                         continue;
1351                 ++rchain->hmp->mount_count;
1352                 kprintf("hammer2_mount hmp=%p ++mount_count=%d\n",
1353                         rchain->hmp, rchain->hmp->mount_count);
1354         }
1355
1356         /*
1357          * Create missing Xop threads
1358          */
1359         hammer2_xop_helper_create(pmp);
1360 }
1361
1362 /*
1363  * Mount helper, unhook the system mount from our PFS.
1364  * The mount lock is held.
1365  *
1366  * If hmp is supplied a mount responsible for being the first to open
1367  * the block device failed and the block device and all PFSs using the
1368  * block device must be cleaned up.
1369  *
1370  * If pmp is supplied multiple devices might be backing the PFS and each
1371  * must be disconnect.  This might not be the last PFS using some of the
1372  * underlying devices.  Also, we have to adjust our hmp->mount_count
1373  * accounting for the devices backing the pmp which is now undergoing an
1374  * unmount.
1375  */
1376 static
1377 void
1378 hammer2_unmount_helper(struct mount *mp, hammer2_pfs_t *pmp, hammer2_dev_t *hmp)
1379 {
1380         hammer2_cluster_t *cluster;
1381         hammer2_chain_t *rchain;
1382         struct vnode *devvp;
1383         int dumpcnt;
1384         int ronly = 0;
1385         int i;
1386
1387         /*
1388          * If no device supplied this is a high-level unmount and we have to
1389          * to disconnect the mount, adjust mount_count, and locate devices
1390          * that might now have no mounts.
1391          */
1392         if (pmp) {
1393                 KKASSERT(hmp == NULL);
1394                 KKASSERT((void *)(intptr_t)mp->mnt_data == pmp);
1395                 pmp->mp = NULL;
1396                 mp->mnt_data = NULL;
1397
1398                 /*
1399                  * After pmp->mp is cleared we have to account for
1400                  * mount_count.
1401                  */
1402                 cluster = &pmp->iroot->cluster;
1403                 for (i = 0; i < cluster->nchains; ++i) {
1404                         rchain = cluster->array[i].chain;
1405                         if (rchain == NULL)
1406                                 continue;
1407                         --rchain->hmp->mount_count;
1408                         kprintf("hammer2_unmount hmp=%p --mount_count=%d\n",
1409                                 rchain->hmp, rchain->hmp->mount_count);
1410                         /* scrapping hmp now may invalidate the pmp */
1411                 }
1412 again:
1413                 TAILQ_FOREACH(hmp, &hammer2_mntlist, mntentry) {
1414                         if (hmp->mount_count == 0) {
1415                                 hammer2_unmount_helper(NULL, NULL, hmp);
1416                                 goto again;
1417                         }
1418                 }
1419                 return;
1420         }
1421
1422         /*
1423          * Try to terminate the block device.  We can't terminate it if
1424          * there are still PFSs referencing it.
1425          */
1426         kprintf("hammer2_unmount hmp=%p mount_count=%d\n",
1427                 hmp, hmp->mount_count);
1428         if (hmp->mount_count)
1429                 return;
1430
1431         hammer2_pfsfree_scan(hmp);
1432         hammer2_dev_exlock(hmp);        /* XXX order */
1433
1434         /*
1435          * Cycle the volume data lock as a safety (probably not needed any
1436          * more).  To ensure everything is out we need to flush at least
1437          * three times.  (1) The running of the unlinkq can dirty the
1438          * filesystem, (2) A normal flush can dirty the freemap, and
1439          * (3) ensure that the freemap is fully synchronized.
1440          *
1441          * The next mount's recovery scan can clean everything up but we want
1442          * to leave the filesystem in a 100% clean state on a normal unmount.
1443          */
1444 #if 0
1445         hammer2_voldata_lock(hmp);
1446         hammer2_voldata_unlock(hmp);
1447 #endif
1448         hammer2_iocom_uninit(hmp);
1449
1450         if ((hmp->vchain.flags | hmp->fchain.flags) &
1451             HAMMER2_CHAIN_FLUSH_MASK) {
1452                 kprintf("hammer2_unmount: chains left over "
1453                         "after final sync\n");
1454                 kprintf("    vchain %08x\n", hmp->vchain.flags);
1455                 kprintf("    fchain %08x\n", hmp->fchain.flags);
1456
1457                 if (hammer2_debug & 0x0010)
1458                         Debugger("entered debugger");
1459         }
1460
1461         KKASSERT(hmp->spmp == NULL);
1462
1463         /*
1464          * Finish up with the device vnode
1465          */
1466         if ((devvp = hmp->devvp) != NULL) {
1467                 vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
1468                 vinvalbuf(devvp, (ronly ? 0 : V_SAVE), 0, 0);
1469                 hmp->devvp = NULL;
1470                 VOP_CLOSE(devvp, (ronly ? FREAD : FREAD|FWRITE), NULL);
1471                 vn_unlock(devvp);
1472                 vrele(devvp);
1473                 devvp = NULL;
1474         }
1475
1476         /*
1477          * Clear vchain/fchain flags that might prevent final cleanup
1478          * of these chains.
1479          */
1480         if (hmp->vchain.flags & HAMMER2_CHAIN_MODIFIED) {
1481                 atomic_clear_int(&hmp->vchain.flags,
1482                                  HAMMER2_CHAIN_MODIFIED);
1483                 hammer2_pfs_memory_wakeup(hmp->vchain.pmp);
1484                 hammer2_chain_drop(&hmp->vchain);
1485         }
1486         if (hmp->vchain.flags & HAMMER2_CHAIN_UPDATE) {
1487                 atomic_clear_int(&hmp->vchain.flags,
1488                                  HAMMER2_CHAIN_UPDATE);
1489                 hammer2_chain_drop(&hmp->vchain);
1490         }
1491
1492         if (hmp->fchain.flags & HAMMER2_CHAIN_MODIFIED) {
1493                 atomic_clear_int(&hmp->fchain.flags,
1494                                  HAMMER2_CHAIN_MODIFIED);
1495                 hammer2_pfs_memory_wakeup(hmp->fchain.pmp);
1496                 hammer2_chain_drop(&hmp->fchain);
1497         }
1498         if (hmp->fchain.flags & HAMMER2_CHAIN_UPDATE) {
1499                 atomic_clear_int(&hmp->fchain.flags,
1500                                  HAMMER2_CHAIN_UPDATE);
1501                 hammer2_chain_drop(&hmp->fchain);
1502         }
1503
1504         /*
1505          * Final drop of embedded freemap root chain to
1506          * clean up fchain.core (fchain structure is not
1507          * flagged ALLOCATED so it is cleaned out and then
1508          * left to rot).
1509          */
1510         hammer2_chain_drop(&hmp->fchain);
1511
1512         /*
1513          * Final drop of embedded volume root chain to clean
1514          * up vchain.core (vchain structure is not flagged
1515          * ALLOCATED so it is cleaned out and then left to
1516          * rot).
1517          */
1518         dumpcnt = 50;
1519         hammer2_dump_chain(&hmp->vchain, 0, &dumpcnt, 'v');
1520         dumpcnt = 50;
1521         hammer2_dump_chain(&hmp->fchain, 0, &dumpcnt, 'f');
1522         hammer2_dev_unlock(hmp);
1523         hammer2_chain_drop(&hmp->vchain);
1524
1525         hammer2_io_cleanup(hmp, &hmp->iotree);
1526         if (hmp->iofree_count) {
1527                 kprintf("io_cleanup: %d I/O's left hanging\n",
1528                         hmp->iofree_count);
1529         }
1530
1531         TAILQ_REMOVE(&hammer2_mntlist, hmp, mntentry);
1532         kmalloc_destroy(&hmp->mchain);
1533         kfree(hmp, M_HAMMER2);
1534 }
1535
1536 static
1537 int
1538 hammer2_vfs_vget(struct mount *mp, struct vnode *dvp,
1539              ino_t ino, struct vnode **vpp)
1540 {
1541         kprintf("hammer2_vget\n");
1542         return (EOPNOTSUPP);
1543 }
1544
1545 static
1546 int
1547 hammer2_vfs_root(struct mount *mp, struct vnode **vpp)
1548 {
1549         hammer2_pfs_t *pmp;
1550         int error;
1551         struct vnode *vp;
1552
1553         pmp = MPTOPMP(mp);
1554         if (pmp->iroot == NULL) {
1555                 *vpp = NULL;
1556                 return EINVAL;
1557         }
1558
1559         error = 0;
1560         hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1561
1562         while (pmp->inode_tid == 0) {
1563                 hammer2_xop_ipcluster_t *xop;
1564                 hammer2_inode_meta_t *meta;
1565
1566                 xop = hammer2_xop_alloc(pmp->iroot, HAMMER2_XOP_MODIFYING);
1567                 hammer2_xop_start(&xop->head, hammer2_xop_ipcluster);
1568                 error = hammer2_xop_collect(&xop->head, 0);
1569
1570                 if (error == 0) {
1571                         meta = &xop->head.cluster.focus->data->ipdata.meta;
1572                         pmp->iroot->meta = *meta;
1573                         pmp->inode_tid = meta->pfs_inum + 1;
1574                         if (pmp->inode_tid < HAMMER2_INODE_START)
1575                                 pmp->inode_tid = HAMMER2_INODE_START;
1576                         pmp->modify_tid =
1577                                 xop->head.cluster.focus->bref.modify_tid + 1;
1578                         kprintf("PFS: Starting inode %jd\n",
1579                                 (intmax_t)pmp->inode_tid);
1580                         kprintf("PMP focus good set nextino=%ld mod=%016jx\n",
1581                                 pmp->inode_tid, pmp->modify_tid);
1582                         wakeup(&pmp->iroot);
1583
1584                         hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1585
1586                         /*
1587                          * Prime the mount info.
1588                          */
1589                         hammer2_vfs_statfs(mp, &mp->mnt_stat, NULL);
1590
1591                         /*
1592                          * With the cluster operational, check for and
1593                          * install ihidden if needed.  The install_hidden
1594                          * code needs to get a transaction so we must unlock
1595                          * iroot around it.
1596                          *
1597                          * This is only applicable PFS mounts, there is no
1598                          * hidden directory in the spmp.
1599                          */
1600                         hammer2_inode_unlock(pmp->iroot);
1601                         hammer2_inode_install_hidden(pmp);
1602                         hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1603
1604                         break;
1605                 }
1606
1607                 /*
1608                  * Loop, try again
1609                  */
1610                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
1611                 hammer2_inode_unlock(pmp->iroot);
1612                 error = tsleep(&pmp->iroot, PCATCH, "h2root", hz);
1613                 hammer2_inode_lock(pmp->iroot, HAMMER2_RESOLVE_SHARED);
1614                 if (error == EINTR)
1615                         break;
1616         }
1617
1618         if (error) {
1619                 hammer2_inode_unlock(pmp->iroot);
1620                 *vpp = NULL;
1621         } else {
1622                 vp = hammer2_igetv(pmp->iroot, &error);
1623                 hammer2_inode_unlock(pmp->iroot);
1624                 *vpp = vp;
1625         }
1626
1627         return (error);
1628 }
1629
1630 /*
1631  * Filesystem status
1632  *
1633  * XXX incorporate ipdata->meta.inode_quota and data_quota
1634  */
1635 static
1636 int
1637 hammer2_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
1638 {
1639         hammer2_pfs_t *pmp;
1640         hammer2_dev_t *hmp;
1641         hammer2_blockref_t bref;
1642         int i;
1643
1644         /*
1645          * NOTE: iroot might not have validated the cluster yet.
1646          */
1647         pmp = MPTOPMP(mp);
1648
1649         mp->mnt_stat.f_files = 0;
1650         mp->mnt_stat.f_ffree = 0;
1651         mp->mnt_stat.f_blocks = 0;
1652         mp->mnt_stat.f_bfree = 0;
1653         mp->mnt_stat.f_bavail = 0;
1654
1655         for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1656                 hmp = pmp->pfs_hmps[i];
1657                 if (hmp == NULL)
1658                         continue;
1659                 if (pmp->iroot->cluster.array[i].chain)
1660                         bref = pmp->iroot->cluster.array[i].chain->bref;
1661                 else
1662                         bzero(&bref, sizeof(bref));
1663
1664                 mp->mnt_stat.f_files = bref.inode_count;
1665                 mp->mnt_stat.f_ffree = 0;
1666                 mp->mnt_stat.f_blocks = (bref.data_count +
1667                                          hmp->voldata.allocator_free) /
1668                                         mp->mnt_vstat.f_bsize;
1669                 mp->mnt_stat.f_bfree =  hmp->voldata.allocator_free /
1670                                         mp->mnt_vstat.f_bsize;
1671                 mp->mnt_stat.f_bavail = mp->mnt_stat.f_bfree;
1672
1673                 *sbp = mp->mnt_stat;
1674         }
1675         return (0);
1676 }
1677
1678 static
1679 int
1680 hammer2_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
1681 {
1682         hammer2_pfs_t *pmp;
1683         hammer2_dev_t *hmp;
1684         hammer2_blockref_t bref;
1685         int i;
1686
1687         /*
1688          * NOTE: iroot might not have validated the cluster yet.
1689          */
1690         pmp = MPTOPMP(mp);
1691
1692         mp->mnt_vstat.f_bsize = 0;
1693         mp->mnt_vstat.f_files = 0;
1694         mp->mnt_vstat.f_ffree = 0;
1695         mp->mnt_vstat.f_blocks = 0;
1696         mp->mnt_vstat.f_bfree = 0;
1697         mp->mnt_vstat.f_bavail = 0;
1698
1699         for (i = 0; i < pmp->iroot->cluster.nchains; ++i) {
1700                 hmp = pmp->pfs_hmps[i];
1701                 if (hmp == NULL)
1702                         continue;
1703                 if (pmp->iroot->cluster.array[i].chain)
1704                         bref = pmp->iroot->cluster.array[i].chain->bref;
1705                 else
1706                         bzero(&bref, sizeof(bref));
1707
1708                 mp->mnt_vstat.f_bsize = HAMMER2_PBUFSIZE;
1709                 mp->mnt_vstat.f_files = bref.inode_count;
1710                 mp->mnt_vstat.f_ffree = 0;
1711                 mp->mnt_vstat.f_blocks = (bref.data_count +
1712                                          hmp->voldata.allocator_free) /
1713                                         mp->mnt_vstat.f_bsize;
1714                 mp->mnt_vstat.f_bfree = hmp->voldata.allocator_free /
1715                                         mp->mnt_vstat.f_bsize;
1716                 mp->mnt_vstat.f_bavail = mp->mnt_vstat.f_bfree;
1717
1718                 *sbp = mp->mnt_vstat;
1719         }
1720         return (0);
1721 }
1722
1723 /*
1724  * Mount-time recovery (RW mounts)
1725  *
1726  * Updates to the free block table are allowed to lag flushes by one
1727  * transaction.  In case of a crash, then on a fresh mount we must do an
1728  * incremental scan of the last committed transaction id and make sure that
1729  * all related blocks have been marked allocated.
1730  *
1731  * The super-root topology and each PFS has its own transaction id domain,
1732  * so we must track PFS boundary transitions.
1733  */
1734 struct hammer2_recovery_elm {
1735         TAILQ_ENTRY(hammer2_recovery_elm) entry;
1736         hammer2_chain_t *chain;
1737         hammer2_tid_t sync_tid;
1738 };
1739
1740 TAILQ_HEAD(hammer2_recovery_list, hammer2_recovery_elm);
1741
1742 struct hammer2_recovery_info {
1743         struct hammer2_recovery_list list;
1744         hammer2_tid_t   mtid;
1745         int     depth;
1746 };
1747
1748 static int hammer2_recovery_scan(hammer2_dev_t *hmp,
1749                         hammer2_chain_t *parent,
1750                         struct hammer2_recovery_info *info,
1751                         hammer2_tid_t sync_tid);
1752
1753 #define HAMMER2_RECOVERY_MAXDEPTH       10
1754
1755 static
1756 int
1757 hammer2_recovery(hammer2_dev_t *hmp)
1758 {
1759         struct hammer2_recovery_info info;
1760         struct hammer2_recovery_elm *elm;
1761         hammer2_chain_t *parent;
1762         hammer2_tid_t sync_tid;
1763         hammer2_tid_t mirror_tid;
1764         int error;
1765         int cumulative_error = 0;
1766
1767         hammer2_trans_init(hmp->spmp, 0);
1768
1769         sync_tid = hmp->voldata.freemap_tid;
1770         mirror_tid = hmp->voldata.mirror_tid;
1771
1772         kprintf("hammer2 mount \"%s\": ", hmp->devrepname);
1773         if (sync_tid >= mirror_tid) {
1774                 kprintf(" no recovery needed\n");
1775         } else {
1776                 kprintf(" freemap recovery %016jx-%016jx\n",
1777                         sync_tid + 1, mirror_tid);
1778         }
1779
1780         TAILQ_INIT(&info.list);
1781         info.depth = 0;
1782         parent = hammer2_chain_lookup_init(&hmp->vchain, 0);
1783         cumulative_error = hammer2_recovery_scan(hmp, parent, &info, sync_tid);
1784         hammer2_chain_lookup_done(parent);
1785
1786         while ((elm = TAILQ_FIRST(&info.list)) != NULL) {
1787                 TAILQ_REMOVE(&info.list, elm, entry);
1788                 parent = elm->chain;
1789                 sync_tid = elm->sync_tid;
1790                 kfree(elm, M_HAMMER2);
1791
1792                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1793                 error = hammer2_recovery_scan(hmp, parent, &info,
1794                                               hmp->voldata.freemap_tid);
1795                 hammer2_chain_unlock(parent);
1796                 hammer2_chain_drop(parent);     /* drop elm->chain ref */
1797                 if (error)
1798                         cumulative_error = error;
1799         }
1800         hammer2_trans_done(hmp->spmp);
1801
1802         return cumulative_error;
1803 }
1804
1805 static
1806 int
1807 hammer2_recovery_scan(hammer2_dev_t *hmp, hammer2_chain_t *parent,
1808                       struct hammer2_recovery_info *info,
1809                       hammer2_tid_t sync_tid)
1810 {
1811         const hammer2_inode_data_t *ripdata;
1812         hammer2_chain_t *chain;
1813         hammer2_blockref_t bref;
1814         int cache_index;
1815         int cumulative_error = 0;
1816         int error;
1817         int first;
1818
1819         /*
1820          * Adjust freemap to ensure that the block(s) are marked allocated.
1821          */
1822         if (parent->bref.type != HAMMER2_BREF_TYPE_VOLUME) {
1823                 hammer2_freemap_adjust(hmp, &parent->bref,
1824                                        HAMMER2_FREEMAP_DORECOVER);
1825         }
1826
1827         /*
1828          * Check type for recursive scan
1829          */
1830         switch(parent->bref.type) {
1831         case HAMMER2_BREF_TYPE_VOLUME:
1832                 /* data already instantiated */
1833                 break;
1834         case HAMMER2_BREF_TYPE_INODE:
1835                 /*
1836                  * Must instantiate data for DIRECTDATA test and also
1837                  * for recursion.
1838                  */
1839                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1840                 ripdata = &hammer2_chain_rdata(parent)->ipdata;
1841                 if (ripdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA) {
1842                         /* not applicable to recovery scan */
1843                         hammer2_chain_unlock(parent);
1844                         return 0;
1845                 }
1846                 hammer2_chain_unlock(parent);
1847                 break;
1848         case HAMMER2_BREF_TYPE_INDIRECT:
1849                 /*
1850                  * Must instantiate data for recursion
1851                  */
1852                 hammer2_chain_lock(parent, HAMMER2_RESOLVE_ALWAYS);
1853                 hammer2_chain_unlock(parent);
1854                 break;
1855         case HAMMER2_BREF_TYPE_DATA:
1856         case HAMMER2_BREF_TYPE_FREEMAP:
1857         case HAMMER2_BREF_TYPE_FREEMAP_NODE:
1858         case HAMMER2_BREF_TYPE_FREEMAP_LEAF:
1859                 /* not applicable to recovery scan */
1860                 return 0;
1861                 break;
1862         default:
1863                 return EDOM;
1864         }
1865
1866         /*
1867          * Defer operation if depth limit reached or if we are crossing a
1868          * PFS boundary.
1869          */
1870         if (info->depth >= HAMMER2_RECOVERY_MAXDEPTH) {
1871                 struct hammer2_recovery_elm *elm;
1872
1873                 elm = kmalloc(sizeof(*elm), M_HAMMER2, M_ZERO | M_WAITOK);
1874                 elm->chain = parent;
1875                 elm->sync_tid = sync_tid;
1876                 hammer2_chain_ref(parent);
1877                 TAILQ_INSERT_TAIL(&info->list, elm, entry);
1878                 /* unlocked by caller */
1879
1880                 return(0);
1881         }
1882
1883
1884         /*
1885          * Recursive scan of the last flushed transaction only.  We are
1886          * doing this without pmp assignments so don't leave the chains
1887          * hanging around after we are done with them.
1888          */
1889         cache_index = 0;
1890         chain = NULL;
1891         first = 1;
1892
1893         while (hammer2_chain_scan(parent, &chain, &bref,
1894                                   &first, &cache_index,
1895                                   HAMMER2_LOOKUP_NODATA) != NULL) {
1896                 /*
1897                  * If this is a leaf
1898                  */
1899                 if (chain == NULL) {
1900                         if (bref.mirror_tid > sync_tid) {
1901                                 hammer2_freemap_adjust(hmp, &bref,
1902                                                      HAMMER2_FREEMAP_DORECOVER);
1903                         }
1904                         continue;
1905                 }
1906
1907                 /*
1908                  * This may or may not be a recursive node.
1909                  */
1910                 atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
1911                 if (bref.mirror_tid > sync_tid) {
1912                         ++info->depth;
1913                         error = hammer2_recovery_scan(hmp, chain,
1914                                                       info, sync_tid);
1915                         --info->depth;
1916                         if (error)
1917                                 cumulative_error = error;
1918                 }
1919
1920                 /*
1921                  * Flush the recovery at the PFS boundary to stage it for
1922                  * the final flush of the super-root topology.
1923                  */
1924                 if ((bref.flags & HAMMER2_BREF_FLAG_PFSROOT) &&
1925                     (chain->flags & HAMMER2_CHAIN_ONFLUSH)) {
1926                         hammer2_flush(chain, HAMMER2_FLUSH_TOP);
1927                 }
1928         }
1929
1930         return cumulative_error;
1931 }
1932
1933 /*
1934  * Sync a mount point; this is called on a per-mount basis from the
1935  * filesystem syncer process periodically and whenever a user issues
1936  * a sync.
1937  */
1938 int
1939 hammer2_vfs_sync(struct mount *mp, int waitfor)
1940 {
1941         hammer2_xop_flush_t *xop;
1942         struct hammer2_sync_info info;
1943         hammer2_inode_t *iroot;
1944         hammer2_pfs_t *pmp;
1945         int flags;
1946         int error;
1947
1948         pmp = MPTOPMP(mp);
1949         iroot = pmp->iroot;
1950         KKASSERT(iroot);
1951         KKASSERT(iroot->pmp == pmp);
1952
1953         /*
1954          * We can't acquire locks on existing vnodes while in a transaction
1955          * without risking a deadlock.  This assumes that vfsync() can be
1956          * called without the vnode locked (which it can in DragonFly).
1957          * Otherwise we'd have to implement a multi-pass or flag the lock
1958          * failures and retry.
1959          *
1960          * The reclamation code interlocks with the sync list's token
1961          * (by removing the vnode from the scan list) before unlocking
1962          * the inode, giving us time to ref the inode.
1963          */
1964         /*flags = VMSC_GETVP;*/
1965         flags = 0;
1966         if (waitfor & MNT_LAZY)
1967                 flags |= VMSC_ONEPASS;
1968
1969 #if 0
1970         /*
1971          * Preflush the vnodes using a normal transaction before interlocking
1972          * with a flush transaction.
1973          */
1974         hammer2_trans_init(pmp, 0);
1975         info.error = 0;
1976         info.waitfor = MNT_NOWAIT;
1977         vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
1978         hammer2_trans_done(pmp);
1979 #endif
1980
1981         /*
1982          * Start our flush transaction.  This does not return until all
1983          * concurrent transactions have completed and will prevent any
1984          * new transactions from running concurrently, except for the
1985          * buffer cache transactions.
1986          *
1987          * For efficiency do an async pass before making sure with a
1988          * synchronous pass on all related buffer cache buffers.  It
1989          * should theoretically not be possible for any new file buffers
1990          * to be instantiated during this sequence.
1991          */
1992         hammer2_trans_init(pmp, HAMMER2_TRANS_ISFLUSH |
1993                                 HAMMER2_TRANS_PREFLUSH);
1994         hammer2_inode_run_unlinkq(pmp);
1995
1996         info.error = 0;
1997         info.waitfor = MNT_NOWAIT;
1998         vsyncscan(mp, flags | VMSC_NOWAIT, hammer2_sync_scan2, &info);
1999         info.waitfor = MNT_WAIT;
2000         vsyncscan(mp, flags, hammer2_sync_scan2, &info);
2001
2002         /*
2003          * Clear PREFLUSH.  This prevents (or asserts on) any new logical
2004          * buffer cache flushes which occur during the flush.  Device buffers
2005          * are not affected.
2006          */
2007         hammer2_bioq_sync(pmp);
2008         hammer2_trans_clear_preflush(pmp);
2009
2010         /*
2011          * Use the XOP interface to concurrently flush all nodes to
2012          * synchronize the PFSROOT subtopology to the media.  A standard
2013          * end-of-scan ENOENT error indicates cluster sufficiency.
2014          *
2015          * Note that this flush will not be visible on crash recovery until
2016          * we flush the super-root topology in the next loop.
2017          *
2018          * XXX For now wait for all flushes to complete.
2019          */
2020         if (iroot) {
2021                 xop = hammer2_xop_alloc(iroot, HAMMER2_XOP_MODIFYING);
2022                 hammer2_xop_start(&xop->head, hammer2_inode_xop_flush);
2023                 error = hammer2_xop_collect(&xop->head,
2024                                             HAMMER2_XOP_COLLECT_WAITALL);
2025                 hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
2026                 if (error == ENOENT)
2027                         error = 0;
2028         } else {
2029                 error = 0;
2030         }
2031         hammer2_trans_done(pmp);
2032
2033         return (error);
2034 }
2035
2036 /*
2037  * Sync passes.
2038  *
2039  * Note that we ignore the tranasction mtid we got above.  Instead,
2040  * each vfsync below will ultimately get its own via TRANS_BUFCACHE
2041  * transactions.
2042  */
2043 static int
2044 hammer2_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
2045 {
2046         struct hammer2_sync_info *info = data;
2047         hammer2_inode_t *ip;
2048         int error;
2049
2050         /*
2051          * Degenerate cases.  Note that ip == NULL typically means the
2052          * syncer vnode itself and we don't want to vclrisdirty() in that
2053          * situation.
2054          */
2055         ip = VTOI(vp);
2056         if (ip == NULL) {
2057                 return(0);
2058         }
2059         if (vp->v_type == VNON || vp->v_type == VBAD) {
2060                 vclrisdirty(vp);
2061                 return(0);
2062         }
2063
2064         /*
2065          * VOP_FSYNC will start a new transaction so replicate some code
2066          * here to do it inline (see hammer2_vop_fsync()).
2067          *
2068          * WARNING: The vfsync interacts with the buffer cache and might
2069          *          block, we can't hold the inode lock at that time.
2070          *          However, we MUST ref ip before blocking to ensure that
2071          *          it isn't ripped out from under us (since we do not
2072          *          hold a lock on the vnode).
2073          */
2074         hammer2_inode_ref(ip);
2075         if ((ip->flags & HAMMER2_INODE_MODIFIED) ||
2076             !RB_EMPTY(&vp->v_rbdirty_tree)) {
2077                 vfsync(vp, info->waitfor, 1, NULL, NULL);
2078                 if (ip->flags & (HAMMER2_INODE_RESIZED |
2079                                  HAMMER2_INODE_MODIFIED)) {
2080                         hammer2_inode_lock(ip, 0);
2081                         hammer2_inode_chain_sync(ip);
2082                         hammer2_inode_unlock(ip);
2083                 }
2084         }
2085         if ((ip->flags & HAMMER2_INODE_MODIFIED) == 0 &&
2086             RB_EMPTY(&vp->v_rbdirty_tree)) {
2087                 vclrisdirty(vp);
2088         }
2089
2090         hammer2_inode_drop(ip);
2091 #if 1
2092         error = 0;
2093         if (error)
2094                 info->error = error;
2095 #endif
2096         return(0);
2097 }
2098
2099 static
2100 int
2101 hammer2_vfs_vptofh(struct vnode *vp, struct fid *fhp)
2102 {
2103         return (0);
2104 }
2105
2106 static
2107 int
2108 hammer2_vfs_fhtovp(struct mount *mp, struct vnode *rootvp,
2109                struct fid *fhp, struct vnode **vpp)
2110 {
2111         return (0);
2112 }
2113
2114 static
2115 int
2116 hammer2_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
2117                  int *exflagsp, struct ucred **credanonp)
2118 {
2119         return (0);
2120 }
2121
2122 /*
2123  * Support code for hammer2_vfs_mount().  Read, verify, and install the volume
2124  * header into the HMP
2125  *
2126  * XXX read four volhdrs and use the one with the highest TID whos CRC
2127  *     matches.
2128  *
2129  * XXX check iCRCs.
2130  *
2131  * XXX For filesystems w/ less than 4 volhdrs, make sure to not write to
2132  *     nonexistant locations.
2133  *
2134  * XXX Record selected volhdr and ring updates to each of 4 volhdrs
2135  */
2136 static
2137 int
2138 hammer2_install_volume_header(hammer2_dev_t *hmp)
2139 {
2140         hammer2_volume_data_t *vd;
2141         struct buf *bp;
2142         hammer2_crc32_t crc0, crc, bcrc0, bcrc;
2143         int error_reported;
2144         int error;
2145         int valid;
2146         int i;
2147
2148         error_reported = 0;
2149         error = 0;
2150         valid = 0;
2151         bp = NULL;
2152
2153         /*
2154          * There are up to 4 copies of the volume header (syncs iterate
2155          * between them so there is no single master).  We don't trust the
2156          * volu_size field so we don't know precisely how large the filesystem
2157          * is, so depend on the OS to return an error if we go beyond the
2158          * block device's EOF.
2159          */
2160         for (i = 0; i < HAMMER2_NUM_VOLHDRS; i++) {
2161                 error = bread(hmp->devvp, i * HAMMER2_ZONE_BYTES64,
2162                               HAMMER2_VOLUME_BYTES, &bp);
2163                 if (error) {
2164                         brelse(bp);
2165                         bp = NULL;
2166                         continue;
2167                 }
2168
2169                 vd = (struct hammer2_volume_data *) bp->b_data;
2170                 if ((vd->magic != HAMMER2_VOLUME_ID_HBO) &&
2171                     (vd->magic != HAMMER2_VOLUME_ID_ABO)) {
2172                         brelse(bp);
2173                         bp = NULL;
2174                         continue;
2175                 }
2176
2177                 if (vd->magic == HAMMER2_VOLUME_ID_ABO) {
2178                         /* XXX: Reversed-endianness filesystem */
2179                         kprintf("hammer2: reverse-endian filesystem detected");
2180                         brelse(bp);
2181                         bp = NULL;
2182                         continue;
2183                 }
2184
2185                 crc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT0];
2186                 crc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC0_OFF,
2187                                       HAMMER2_VOLUME_ICRC0_SIZE);
2188                 bcrc = vd->icrc_sects[HAMMER2_VOL_ICRC_SECT1];
2189                 bcrc0 = hammer2_icrc32(bp->b_data + HAMMER2_VOLUME_ICRC1_OFF,
2190                                        HAMMER2_VOLUME_ICRC1_SIZE);
2191                 if ((crc0 != crc) || (bcrc0 != bcrc)) {
2192                         kprintf("hammer2 volume header crc "
2193                                 "mismatch copy #%d %08x/%08x\n",
2194                                 i, crc0, crc);
2195                         error_reported = 1;
2196                         brelse(bp);
2197                         bp = NULL;
2198                         continue;
2199                 }
2200                 if (valid == 0 || hmp->voldata.mirror_tid < vd->mirror_tid) {
2201                         valid = 1;
2202                         hmp->voldata = *vd;
2203                         hmp->volhdrno = i;
2204                 }
2205                 brelse(bp);
2206                 bp = NULL;
2207         }
2208         if (valid) {
2209                 hmp->volsync = hmp->voldata;
2210                 error = 0;
2211                 if (error_reported || bootverbose || 1) { /* 1/DEBUG */
2212                         kprintf("hammer2: using volume header #%d\n",
2213                                 hmp->volhdrno);
2214                 }
2215         } else {
2216                 error = EINVAL;
2217                 kprintf("hammer2: no valid volume headers found!\n");
2218         }
2219         return (error);
2220 }
2221
2222 /*
2223  * This handles hysteresis on regular file flushes.  Because the BIOs are
2224  * routed to a thread it is possible for an excessive number to build up
2225  * and cause long front-end stalls long before the runningbuffspace limit
2226  * is hit, so we implement hammer2_flush_pipe to control the
2227  * hysteresis.
2228  *
2229  * This is a particular problem when compression is used.
2230  */
2231 void
2232 hammer2_lwinprog_ref(hammer2_pfs_t *pmp)
2233 {
2234         atomic_add_int(&pmp->count_lwinprog, 1);
2235 }
2236
2237 void
2238 hammer2_lwinprog_drop(hammer2_pfs_t *pmp)
2239 {
2240         int lwinprog;
2241
2242         lwinprog = atomic_fetchadd_int(&pmp->count_lwinprog, -1);
2243         if ((lwinprog & HAMMER2_LWINPROG_WAITING) &&
2244             (lwinprog & HAMMER2_LWINPROG_MASK) <= hammer2_flush_pipe * 2 / 3) {
2245                 atomic_clear_int(&pmp->count_lwinprog,
2246                                  HAMMER2_LWINPROG_WAITING);
2247                 wakeup(&pmp->count_lwinprog);
2248         }
2249         if ((lwinprog & HAMMER2_LWINPROG_WAITING0) &&
2250             (lwinprog & HAMMER2_LWINPROG_MASK) <= 0) {
2251                 atomic_clear_int(&pmp->count_lwinprog,
2252                                  HAMMER2_LWINPROG_WAITING0);
2253                 wakeup(&pmp->count_lwinprog);
2254         }
2255 }
2256
2257 void
2258 hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int flush_pipe)
2259 {
2260         int lwinprog;
2261         int lwflag = (flush_pipe) ? HAMMER2_LWINPROG_WAITING :
2262                                     HAMMER2_LWINPROG_WAITING0;
2263
2264         for (;;) {
2265                 lwinprog = pmp->count_lwinprog;
2266                 cpu_ccfence();
2267                 if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2268                         break;
2269                 tsleep_interlock(&pmp->count_lwinprog, 0);
2270                 atomic_set_int(&pmp->count_lwinprog, lwflag);
2271                 lwinprog = pmp->count_lwinprog;
2272                 if ((lwinprog & HAMMER2_LWINPROG_MASK) <= flush_pipe)
2273                         break;
2274                 tsleep(&pmp->count_lwinprog, PINTERLOCKED, "h2wpipe", hz);
2275         }
2276 }
2277
2278 /*
2279  * Manage excessive memory resource use for chain and related
2280  * structures.
2281  */
2282 void
2283 hammer2_pfs_memory_wait(hammer2_pfs_t *pmp)
2284 {
2285         uint32_t waiting;
2286         uint32_t count;
2287         uint32_t limit;
2288 #if 0
2289         static int zzticks;
2290 #endif
2291
2292         /*
2293          * Atomic check condition and wait.  Also do an early speedup of
2294          * the syncer to try to avoid hitting the wait.
2295          */
2296         for (;;) {
2297                 waiting = pmp->inmem_dirty_chains;
2298                 cpu_ccfence();
2299                 count = waiting & HAMMER2_DIRTYCHAIN_MASK;
2300
2301                 limit = pmp->mp->mnt_nvnodelistsize / 10;
2302                 if (limit < hammer2_limit_dirty_chains)
2303                         limit = hammer2_limit_dirty_chains;
2304                 if (limit < 1000)
2305                         limit = 1000;
2306
2307 #if 0
2308                 if ((int)(ticks - zzticks) > hz) {
2309                         zzticks = ticks;
2310                         kprintf("count %ld %ld\n", count, limit);
2311                 }
2312 #endif
2313
2314                 /*
2315                  * Block if there are too many dirty chains present, wait
2316                  * for the flush to clean some out.
2317                  */
2318                 if (count > limit) {
2319                         tsleep_interlock(&pmp->inmem_dirty_chains, 0);
2320                         if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2321                                                waiting,
2322                                        waiting | HAMMER2_DIRTYCHAIN_WAITING)) {
2323                                 speedup_syncer(pmp->mp);
2324                                 tsleep(&pmp->inmem_dirty_chains, PINTERLOCKED,
2325                                        "chnmem", hz);
2326                         }
2327                         continue;       /* loop on success or fail */
2328                 }
2329
2330                 /*
2331                  * Try to start an early flush before we are forced to block.
2332                  */
2333                 if (count > limit * 7 / 10)
2334                         speedup_syncer(pmp->mp);
2335                 break;
2336         }
2337 }
2338
2339 void
2340 hammer2_pfs_memory_inc(hammer2_pfs_t *pmp)
2341 {
2342         if (pmp) {
2343                 atomic_add_int(&pmp->inmem_dirty_chains, 1);
2344         }
2345 }
2346
2347 void
2348 hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp)
2349 {
2350         uint32_t waiting;
2351
2352         if (pmp == NULL)
2353                 return;
2354
2355         for (;;) {
2356                 waiting = pmp->inmem_dirty_chains;
2357                 cpu_ccfence();
2358                 if (atomic_cmpset_int(&pmp->inmem_dirty_chains,
2359                                        waiting,
2360                                        (waiting - 1) &
2361                                         ~HAMMER2_DIRTYCHAIN_WAITING)) {
2362                         break;
2363                 }
2364         }
2365
2366         if (waiting & HAMMER2_DIRTYCHAIN_WAITING)
2367                 wakeup(&pmp->inmem_dirty_chains);
2368 }
2369
2370 /*
2371  * Debugging
2372  */
2373 void
2374 hammer2_dump_chain(hammer2_chain_t *chain, int tab, int *countp, char pfx)
2375 {
2376         hammer2_chain_t *scan;
2377         hammer2_chain_t *parent;
2378
2379         --*countp;
2380         if (*countp == 0) {
2381                 kprintf("%*.*s...\n", tab, tab, "");
2382                 return;
2383         }
2384         if (*countp < 0)
2385                 return;
2386         kprintf("%*.*s%c-chain %p.%d %016jx/%d mir=%016jx\n",
2387                 tab, tab, "", pfx,
2388                 chain, chain->bref.type,
2389                 chain->bref.key, chain->bref.keybits,
2390                 chain->bref.mirror_tid);
2391
2392         kprintf("%*.*s      [%08x] (%s) refs=%d",
2393                 tab, tab, "",
2394                 chain->flags,
2395                 ((chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
2396                 chain->data) ?  (char *)chain->data->ipdata.filename : "?"),
2397                 chain->refs);
2398
2399         parent = chain->parent;
2400         if (parent)
2401                 kprintf("\n%*.*s      p=%p [pflags %08x prefs %d",
2402                         tab, tab, "",
2403                         parent, parent->flags, parent->refs);
2404         if (RB_EMPTY(&chain->core.rbtree)) {
2405                 kprintf("\n");
2406         } else {
2407                 kprintf(" {\n");
2408                 RB_FOREACH(scan, hammer2_chain_tree, &chain->core.rbtree)
2409                         hammer2_dump_chain(scan, tab + 4, countp, 'a');
2410                 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->data)
2411                         kprintf("%*.*s}(%s)\n", tab, tab, "",
2412                                 chain->data->ipdata.filename);
2413                 else
2414                         kprintf("%*.*s}\n", tab, tab, "");
2415         }
2416 }