1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 
  22 /*
  23  * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright 2016 Joyent, Inc.
  25  * Copyright 2016 Toomas Soome <tsoome@me.com>
  26  * Copyright (c) 2016, 2017 by Delphix. All rights reserved.
  27  * Copyright 2016 Nexenta Systems, Inc.
  28  * Copyright 2017 RackTop Systems.
  29  */
  30 
  31 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
  32 /*        All Rights Reserved   */
  33 
  34 /*
  35  * University Copyright- Copyright (c) 1982, 1986, 1988
  36  * The Regents of the University of California
  37  * All Rights Reserved
  38  *
  39  * University Acknowledgment- Portions of this document are derived from
  40  * software developed by the University of California, Berkeley, and its
  41  * contributors.
  42  */
  43 
  44 #include <sys/types.h>
  45 #include <sys/t_lock.h>
  46 #include <sys/param.h>
  47 #include <sys/errno.h>
  48 #include <sys/user.h>
  49 #include <sys/fstyp.h>
  50 #include <sys/kmem.h>
  51 #include <sys/systm.h>
  52 #include <sys/proc.h>
  53 #include <sys/mount.h>
  54 #include <sys/vfs.h>
  55 #include <sys/vfs_opreg.h>
  56 #include <sys/fem.h>
  57 #include <sys/mntent.h>
  58 #include <sys/stat.h>
  59 #include <sys/statvfs.h>
  60 #include <sys/statfs.h>
  61 #include <sys/cred.h>
  62 #include <sys/vnode.h>
  63 #include <sys/rwstlock.h>
  64 #include <sys/dnlc.h>
  65 #include <sys/file.h>
  66 #include <sys/time.h>
  67 #include <sys/atomic.h>
  68 #include <sys/cmn_err.h>
  69 #include <sys/buf.h>
  70 #include <sys/swap.h>
  71 #include <sys/debug.h>
  72 #include <sys/vnode.h>
  73 #include <sys/modctl.h>
  74 #include <sys/ddi.h>
  75 #include <sys/pathname.h>
  76 #include <sys/bootconf.h>
  77 #include <sys/dumphdr.h>
  78 #include <sys/dc_ki.h>
  79 #include <sys/poll.h>
  80 #include <sys/sunddi.h>
  81 #include <sys/sysmacros.h>
  82 #include <sys/zone.h>
  83 #include <sys/policy.h>
  84 #include <sys/ctfs.h>
  85 #include <sys/objfs.h>
  86 #include <sys/console.h>
  87 #include <sys/reboot.h>
  88 #include <sys/attr.h>
  89 #include <sys/zio.h>
  90 #include <sys/spa.h>
  91 #include <sys/lofi.h>
  92 #include <sys/bootprops.h>
  93 
  94 #include <vm/page.h>
  95 
  96 #include <fs/fs_subr.h>
  97 /* Private interfaces to create vopstats-related data structures */
  98 extern void             initialize_vopstats(vopstats_t *);
  99 extern vopstats_t       *get_fstype_vopstats(struct vfs *, struct vfssw *);
 100 extern vsk_anchor_t     *get_vskstat_anchor(struct vfs *);
 101 
 102 static void vfs_clearmntopt_nolock(mntopts_t *, const char *, int);
 103 static void vfs_setmntopt_nolock(mntopts_t *, const char *,
 104     const char *, int, int);
 105 static int  vfs_optionisset_nolock(const mntopts_t *, const char *, char **);
 106 static void vfs_freemnttab(struct vfs *);
 107 static void vfs_freeopt(mntopt_t *);
 108 static void vfs_swapopttbl_nolock(mntopts_t *, mntopts_t *);
 109 static void vfs_swapopttbl(mntopts_t *, mntopts_t *);
 110 static void vfs_copyopttbl_extend(const mntopts_t *, mntopts_t *, int);
 111 static void vfs_createopttbl_extend(mntopts_t *, const char *,
 112     const mntopts_t *);
 113 static char **vfs_copycancelopt_extend(char **const, int);
 114 static void vfs_freecancelopt(char **);
 115 static void getrootfs(char **, char **);
 116 static int getmacpath(dev_info_t *, void *);
 117 static void vfs_mnttabvp_setup(void);
 118 
 119 struct ipmnt {
 120         struct ipmnt    *mip_next;
 121         dev_t           mip_dev;
 122         struct vfs      *mip_vfsp;
 123 };
 124 
 125 static kmutex_t         vfs_miplist_mutex;
 126 static struct ipmnt     *vfs_miplist = NULL;
 127 static struct ipmnt     *vfs_miplist_end = NULL;
 128 
 129 static kmem_cache_t *vfs_cache; /* Pointer to VFS kmem cache */
 130 
 131 /*
 132  * VFS global data.
 133  */
 134 vnode_t *rootdir;               /* pointer to root inode vnode. */
 135 vnode_t *devicesdir;            /* pointer to inode of devices root */
 136 vnode_t *devdir;                /* pointer to inode of dev root */
 137 
 138 char *server_rootpath;          /* root path for diskless clients */
 139 char *server_hostname;          /* hostname of diskless server */
 140 
 141 static struct vfs root;
 142 static struct vfs devices;
 143 static struct vfs dev;
 144 struct vfs *rootvfs = &root;        /* pointer to root vfs; head of VFS list. */
 145 rvfs_t *rvfs_list;              /* array of vfs ptrs for vfs hash list */
 146 int vfshsz = 512;               /* # of heads/locks in vfs hash arrays */
 147                                 /* must be power of 2!  */
 148 timespec_t vfs_mnttab_ctime;    /* mnttab created time */
 149 timespec_t vfs_mnttab_mtime;    /* mnttab last modified time */
 150 char *vfs_dummyfstype = "\0";
 151 struct pollhead vfs_pollhd;     /* for mnttab pollers */
 152 struct vnode *vfs_mntdummyvp;   /* to fake mnttab read/write for file events */
 153 int     mntfstype;              /* will be set once mnt fs is mounted */
 154 
 155 /*
 156  * Table for generic options recognized in the VFS layer and acted
 157  * on at this level before parsing file system specific options.
 158  * The nosuid option is stronger than any of the devices and setuid
 159  * options, so those are canceled when nosuid is seen.
 160  *
 161  * All options which are added here need to be added to the
 162  * list of standard options in usr/src/cmd/fs.d/fslib.c as well.
 163  */
 164 /*
 165  * VFS Mount options table
 166  */
 167 static char *ro_cancel[] = { MNTOPT_RW, NULL };
 168 static char *rw_cancel[] = { MNTOPT_RO, NULL };
 169 static char *suid_cancel[] = { MNTOPT_NOSUID, NULL };
 170 static char *nosuid_cancel[] = { MNTOPT_SUID, MNTOPT_DEVICES, MNTOPT_NODEVICES,
 171     MNTOPT_NOSETUID, MNTOPT_SETUID, NULL };
 172 static char *devices_cancel[] = { MNTOPT_NODEVICES, NULL };
 173 static char *nodevices_cancel[] = { MNTOPT_DEVICES, NULL };
 174 static char *setuid_cancel[] = { MNTOPT_NOSETUID, NULL };
 175 static char *nosetuid_cancel[] = { MNTOPT_SETUID, NULL };
 176 static char *nbmand_cancel[] = { MNTOPT_NONBMAND, NULL };
 177 static char *nonbmand_cancel[] = { MNTOPT_NBMAND, NULL };
 178 static char *exec_cancel[] = { MNTOPT_NOEXEC, NULL };
 179 static char *noexec_cancel[] = { MNTOPT_EXEC, NULL };
 180 
 181 static const mntopt_t mntopts[] = {
 182 /*
 183  *      option name             cancel options          default arg     flags
 184  */
 185         { MNTOPT_REMOUNT,       NULL,                   NULL,
 186                 MO_NODISPLAY, (void *)0 },
 187         { MNTOPT_RO,            ro_cancel,              NULL,           0,
 188                 (void *)0 },
 189         { MNTOPT_RW,            rw_cancel,              NULL,           0,
 190                 (void *)0 },
 191         { MNTOPT_SUID,          suid_cancel,            NULL,           0,
 192                 (void *)0 },
 193         { MNTOPT_NOSUID,        nosuid_cancel,          NULL,           0,
 194                 (void *)0 },
 195         { MNTOPT_DEVICES,       devices_cancel,         NULL,           0,
 196                 (void *)0 },
 197         { MNTOPT_NODEVICES,     nodevices_cancel,       NULL,           0,
 198                 (void *)0 },
 199         { MNTOPT_SETUID,        setuid_cancel,          NULL,           0,
 200                 (void *)0 },
 201         { MNTOPT_NOSETUID,      nosetuid_cancel,        NULL,           0,
 202                 (void *)0 },
 203         { MNTOPT_NBMAND,        nbmand_cancel,          NULL,           0,
 204                 (void *)0 },
 205         { MNTOPT_NONBMAND,      nonbmand_cancel,        NULL,           0,
 206                 (void *)0 },
 207         { MNTOPT_EXEC,          exec_cancel,            NULL,           0,
 208                 (void *)0 },
 209         { MNTOPT_NOEXEC,        noexec_cancel,          NULL,           0,
 210                 (void *)0 },
 211 };
 212 
 213 const mntopts_t vfs_mntopts = {
 214         sizeof (mntopts) / sizeof (mntopt_t),
 215         (mntopt_t *)&mntopts[0]
 216 };
 217 
 218 /*
 219  * File system operation dispatch functions.
 220  */
 221 
 222 int
 223 fsop_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
 224 {
 225         return (*(vfsp)->vfs_op->vfs_mount)(vfsp, mvp, uap, cr);
 226 }
 227 
 228 int
 229 fsop_unmount(vfs_t *vfsp, int flag, cred_t *cr)
 230 {
 231         return (*(vfsp)->vfs_op->vfs_unmount)(vfsp, flag, cr);
 232 }
 233 
 234 int
 235 fsop_root(vfs_t *vfsp, vnode_t **vpp)
 236 {
 237         refstr_t *mntpt;
 238         int ret = (*(vfsp)->vfs_op->vfs_root)(vfsp, vpp);
 239         /*
 240          * Make sure this root has a path.  With lofs, it is possible to have
 241          * a NULL mountpoint.
 242          */
 243         if (ret == 0 && vfsp->vfs_mntpt != NULL &&
 244             (*vpp)->v_path == vn_vpath_empty) {
 245                 const char *path;
 246 
 247                 mntpt = vfs_getmntpoint(vfsp);
 248                 path = refstr_value(mntpt);
 249                 vn_setpath_str(*vpp, path, strlen(path));
 250                 refstr_rele(mntpt);
 251         }
 252 
 253         return (ret);
 254 }
 255 
 256 int
 257 fsop_statfs(vfs_t *vfsp, statvfs64_t *sp)
 258 {
 259         return (*(vfsp)->vfs_op->vfs_statvfs)(vfsp, sp);
 260 }
 261 
 262 int
 263 fsop_sync(vfs_t *vfsp, short flag, cred_t *cr)
 264 {
 265         return (*(vfsp)->vfs_op->vfs_sync)(vfsp, flag, cr);
 266 }
 267 
 268 int
 269 fsop_vget(vfs_t *vfsp, vnode_t **vpp, fid_t *fidp)
 270 {
 271         /*
 272          * In order to handle system attribute fids in a manner
 273          * transparent to the underlying fs, we embed the fid for
 274          * the sysattr parent object in the sysattr fid and tack on
 275          * some extra bytes that only the sysattr layer knows about.
 276          *
 277          * This guarantees that sysattr fids are larger than other fids
 278          * for this vfs. If the vfs supports the sysattr view interface
 279          * (as indicated by VFSFT_SYSATTR_VIEWS), we cannot have a size
 280          * collision with XATTR_FIDSZ.
 281          */
 282         if (vfs_has_feature(vfsp, VFSFT_SYSATTR_VIEWS) &&
 283             fidp->fid_len == XATTR_FIDSZ)
 284                 return (xattr_dir_vget(vfsp, vpp, fidp));
 285 
 286         return (*(vfsp)->vfs_op->vfs_vget)(vfsp, vpp, fidp);
 287 }
 288 
 289 int
 290 fsop_mountroot(vfs_t *vfsp, enum whymountroot reason)
 291 {
 292         return (*(vfsp)->vfs_op->vfs_mountroot)(vfsp, reason);
 293 }
 294 
 295 void
 296 fsop_freefs(vfs_t *vfsp)
 297 {
 298         (*(vfsp)->vfs_op->vfs_freevfs)(vfsp);
 299 }
 300 
 301 int
 302 fsop_vnstate(vfs_t *vfsp, vnode_t *vp, vntrans_t nstate)
 303 {
 304         return ((*(vfsp)->vfs_op->vfs_vnstate)(vfsp, vp, nstate));
 305 }
 306 
 307 int
 308 fsop_sync_by_kind(int fstype, short flag, cred_t *cr)
 309 {
 310         ASSERT((fstype >= 0) && (fstype < nfstype));
 311 
 312         if (ALLOCATED_VFSSW(&vfssw[fstype]) && VFS_INSTALLED(&vfssw[fstype]))
 313                 return (*vfssw[fstype].vsw_vfsops.vfs_sync) (NULL, flag, cr);
 314         else
 315                 return (ENOTSUP);
 316 }
 317 
 318 /*
 319  * File system initialization.  vfs_setfsops() must be called from a file
 320  * system's init routine.
 321  */
 322 
 323 static int
 324 fs_copyfsops(const fs_operation_def_t *template, vfsops_t *actual,
 325     int *unused_ops)
 326 {
 327         static const fs_operation_trans_def_t vfs_ops_table[] = {
 328                 VFSNAME_MOUNT, offsetof(vfsops_t, vfs_mount),
 329                         fs_nosys, fs_nosys,
 330 
 331                 VFSNAME_UNMOUNT, offsetof(vfsops_t, vfs_unmount),
 332                         fs_nosys, fs_nosys,
 333 
 334                 VFSNAME_ROOT, offsetof(vfsops_t, vfs_root),
 335                         fs_nosys, fs_nosys,
 336 
 337                 VFSNAME_STATVFS, offsetof(vfsops_t, vfs_statvfs),
 338                         fs_nosys, fs_nosys,
 339 
 340                 VFSNAME_SYNC, offsetof(vfsops_t, vfs_sync),
 341                         (fs_generic_func_p) fs_sync,
 342                         (fs_generic_func_p) fs_sync,    /* No errors allowed */
 343 
 344                 VFSNAME_VGET, offsetof(vfsops_t, vfs_vget),
 345                         fs_nosys, fs_nosys,
 346 
 347                 VFSNAME_MOUNTROOT, offsetof(vfsops_t, vfs_mountroot),
 348                         fs_nosys, fs_nosys,
 349 
 350                 VFSNAME_FREEVFS, offsetof(vfsops_t, vfs_freevfs),
 351                         (fs_generic_func_p)fs_freevfs,
 352                         (fs_generic_func_p)fs_freevfs,  /* Shouldn't fail */
 353 
 354                 VFSNAME_VNSTATE, offsetof(vfsops_t, vfs_vnstate),
 355                         (fs_generic_func_p)fs_nosys,
 356                         (fs_generic_func_p)fs_nosys,
 357 
 358                 NULL, 0, NULL, NULL
 359         };
 360 
 361         return (fs_build_vector(actual, unused_ops, vfs_ops_table, template));
 362 }
 363 
 364 void
 365 zfs_boot_init(void)
 366 {
 367         if (strcmp(rootfs.bo_fstype, MNTTYPE_ZFS) == 0)
 368                 spa_boot_init();
 369 }
 370 
 371 int
 372 vfs_setfsops(int fstype, const fs_operation_def_t *template, vfsops_t **actual)
 373 {
 374         int error;
 375         int unused_ops;
 376 
 377         /*
 378          * Verify that fstype refers to a valid fs.  Note that
 379          * 0 is valid since it's used to set "stray" ops.
 380          */
 381         if ((fstype < 0) || (fstype >= nfstype))
 382                 return (EINVAL);
 383 
 384         if (!ALLOCATED_VFSSW(&vfssw[fstype]))
 385                 return (EINVAL);
 386 
 387         /* Set up the operations vector. */
 388 
 389         error = fs_copyfsops(template, &vfssw[fstype].vsw_vfsops, &unused_ops);
 390 
 391         if (error != 0)
 392                 return (error);
 393 
 394         vfssw[fstype].vsw_flag |= VSW_INSTALLED;
 395 
 396         if (actual != NULL)
 397                 *actual = &vfssw[fstype].vsw_vfsops;
 398 
 399 #if DEBUG
 400         if (unused_ops != 0)
 401                 cmn_err(CE_WARN, "vfs_setfsops: %s: %d operations supplied "
 402                     "but not used", vfssw[fstype].vsw_name, unused_ops);
 403 #endif
 404 
 405         return (0);
 406 }
 407 
 408 int
 409 vfs_makefsops(const fs_operation_def_t *template, vfsops_t **actual)
 410 {
 411         int error;
 412         int unused_ops;
 413 
 414         *actual = (vfsops_t *)kmem_alloc(sizeof (vfsops_t), KM_SLEEP);
 415 
 416         error = fs_copyfsops(template, *actual, &unused_ops);
 417         if (error != 0) {
 418                 kmem_free(*actual, sizeof (vfsops_t));
 419                 *actual = NULL;
 420                 return (error);
 421         }
 422 
 423         return (0);
 424 }
 425 
 426 /*
 427  * Free a vfsops structure created as a result of vfs_makefsops().
 428  * NOTE: For a vfsops structure initialized by vfs_setfsops(), use
 429  * vfs_freevfsops_by_type().
 430  */
 431 void
 432 vfs_freevfsops(vfsops_t *vfsops)
 433 {
 434         kmem_free(vfsops, sizeof (vfsops_t));
 435 }
 436 
 437 /*
 438  * Since the vfsops structure is part of the vfssw table and wasn't
 439  * really allocated, we're not really freeing anything.  We keep
 440  * the name for consistency with vfs_freevfsops().  We do, however,
 441  * need to take care of a little bookkeeping.
 442  * NOTE: For a vfsops structure created by vfs_setfsops(), use
 443  * vfs_freevfsops_by_type().
 444  */
 445 int
 446 vfs_freevfsops_by_type(int fstype)
 447 {
 448 
 449         /* Verify that fstype refers to a loaded fs (and not fsid 0). */
 450         if ((fstype <= 0) || (fstype >= nfstype))
 451                 return (EINVAL);
 452 
 453         WLOCK_VFSSW();
 454         if ((vfssw[fstype].vsw_flag & VSW_INSTALLED) == 0) {
 455                 WUNLOCK_VFSSW();
 456                 return (EINVAL);
 457         }
 458 
 459         vfssw[fstype].vsw_flag &= ~VSW_INSTALLED;
 460         WUNLOCK_VFSSW();
 461 
 462         return (0);
 463 }
 464 
 465 /* Support routines used to reference vfs_op */
 466 
 467 /* Set the operations vector for a vfs */
 468 void
 469 vfs_setops(vfs_t *vfsp, vfsops_t *vfsops)
 470 {
 471         vfsops_t        *op;
 472 
 473         ASSERT(vfsp != NULL);
 474         ASSERT(vfsops != NULL);
 475 
 476         op = vfsp->vfs_op;
 477         membar_consumer();
 478         if (vfsp->vfs_femhead == NULL &&
 479             atomic_cas_ptr(&vfsp->vfs_op, op, vfsops) == op) {
 480                 return;
 481         }
 482         fsem_setvfsops(vfsp, vfsops);
 483 }
 484 
 485 /* Retrieve the operations vector for a vfs */
 486 vfsops_t *
 487 vfs_getops(vfs_t *vfsp)
 488 {
 489         vfsops_t        *op;
 490 
 491         ASSERT(vfsp != NULL);
 492 
 493         op = vfsp->vfs_op;
 494         membar_consumer();
 495         if (vfsp->vfs_femhead == NULL && op == vfsp->vfs_op) {
 496                 return (op);
 497         } else {
 498                 return (fsem_getvfsops(vfsp));
 499         }
 500 }
 501 
 502 /*
 503  * Returns non-zero (1) if the vfsops matches that of the vfs.
 504  * Returns zero (0) if not.
 505  */
 506 int
 507 vfs_matchops(vfs_t *vfsp, vfsops_t *vfsops)
 508 {
 509         return (vfs_getops(vfsp) == vfsops);
 510 }
 511 
 512 /*
 513  * Returns non-zero (1) if the file system has installed a non-default,
 514  * non-error vfs_sync routine.  Returns zero (0) otherwise.
 515  */
 516 int
 517 vfs_can_sync(vfs_t *vfsp)
 518 {
 519         /* vfs_sync() routine is not the default/error function */
 520         return (vfs_getops(vfsp)->vfs_sync != fs_sync);
 521 }
 522 
 523 /*
 524  * Initialize a vfs structure.
 525  */
 526 void
 527 vfs_init(vfs_t *vfsp, vfsops_t *op, void *data)
 528 {
 529         /* Other initialization has been moved to vfs_alloc() */
 530         vfsp->vfs_count = 0;
 531         vfsp->vfs_next = vfsp;
 532         vfsp->vfs_prev = vfsp;
 533         vfsp->vfs_zone_next = vfsp;
 534         vfsp->vfs_zone_prev = vfsp;
 535         vfsp->vfs_lofi_id = 0;
 536         sema_init(&vfsp->vfs_reflock, 1, NULL, SEMA_DEFAULT, NULL);
 537         vfsimpl_setup(vfsp);
 538         vfsp->vfs_data = (data);
 539         vfs_setops((vfsp), (op));
 540 }
 541 
 542 /*
 543  * Allocate and initialize the vfs implementation private data
 544  * structure, vfs_impl_t.
 545  */
 546 void
 547 vfsimpl_setup(vfs_t *vfsp)
 548 {
 549         int i;
 550 
 551         if (vfsp->vfs_implp != NULL) {
 552                 return;
 553         }
 554 
 555         vfsp->vfs_implp = kmem_alloc(sizeof (vfs_impl_t), KM_SLEEP);
 556         /* Note that these are #define'd in vfs.h */
 557         vfsp->vfs_vskap = NULL;
 558         vfsp->vfs_fstypevsp = NULL;
 559 
 560         /* Set size of counted array, then zero the array */
 561         vfsp->vfs_featureset[0] = VFS_FEATURE_MAXSZ - 1;
 562         for (i = 1; i <  VFS_FEATURE_MAXSZ; i++) {
 563                 vfsp->vfs_featureset[i] = 0;
 564         }
 565 }
 566 
 567 /*
 568  * Release the vfs_impl_t structure, if it exists. Some unbundled
 569  * filesystems may not use the newer version of vfs and thus
 570  * would not contain this implementation private data structure.
 571  */
 572 void
 573 vfsimpl_teardown(vfs_t *vfsp)
 574 {
 575         vfs_impl_t      *vip = vfsp->vfs_implp;
 576 
 577         if (vip == NULL)
 578                 return;
 579 
 580         kmem_free(vfsp->vfs_implp, sizeof (vfs_impl_t));
 581         vfsp->vfs_implp = NULL;
 582 }
 583 
 584 /*
 585  * VFS system calls: mount, umount, syssync, statfs, fstatfs, statvfs,
 586  * fstatvfs, and sysfs moved to common/syscall.
 587  */
 588 
 589 /*
 590  * Update every mounted file system.  We call the vfs_sync operation of
 591  * each file system type, passing it a NULL vfsp to indicate that all
 592  * mounted file systems of that type should be updated.
 593  */
 594 void
 595 vfs_sync(int flag)
 596 {
 597         struct vfssw *vswp;
 598         RLOCK_VFSSW();
 599         for (vswp = &vfssw[1]; vswp < &vfssw[nfstype]; vswp++) {
 600                 if (ALLOCATED_VFSSW(vswp) && VFS_INSTALLED(vswp)) {
 601                         vfs_refvfssw(vswp);
 602                         RUNLOCK_VFSSW();
 603                         (void) (*vswp->vsw_vfsops.vfs_sync)(NULL, flag,
 604                             CRED());
 605                         vfs_unrefvfssw(vswp);
 606                         RLOCK_VFSSW();
 607                 }
 608         }
 609         RUNLOCK_VFSSW();
 610 }
 611 
 612 void
 613 sync(void)
 614 {
 615         vfs_sync(0);
 616 }
 617 
 618 /*
 619  * External routines.
 620  */
 621 
 622 krwlock_t vfssw_lock;   /* lock accesses to vfssw */
 623 
 624 /*
 625  * Lock for accessing the vfs linked list.  Initialized in vfs_mountroot(),
 626  * but otherwise should be accessed only via vfs_list_lock() and
 627  * vfs_list_unlock().  Also used to protect the timestamp for mods to the list.
 628  */
 629 static krwlock_t vfslist;
 630 
 631 /*
 632  * Mount devfs on /devices. This is done right after root is mounted
 633  * to provide device access support for the system
 634  */
 635 static void
 636 vfs_mountdevices(void)
 637 {
 638         struct vfssw *vsw;
 639         struct vnode *mvp;
 640         struct mounta mounta = {        /* fake mounta for devfs_mount() */
 641                 NULL,
 642                 NULL,
 643                 MS_SYSSPACE,
 644                 NULL,
 645                 NULL,
 646                 0,
 647                 NULL,
 648                 0
 649         };
 650 
 651         /*
 652          * _init devfs module to fill in the vfssw
 653          */
 654         if (modload("fs", "devfs") == -1)
 655                 panic("Cannot _init devfs module");
 656 
 657         /*
 658          * Hold vfs
 659          */
 660         RLOCK_VFSSW();
 661         vsw = vfs_getvfsswbyname("devfs");
 662         VFS_INIT(&devices, &vsw->vsw_vfsops, NULL);
 663         VFS_HOLD(&devices);
 664 
 665         /*
 666          * Locate mount point
 667          */
 668         if (lookupname("/devices", UIO_SYSSPACE, FOLLOW, NULLVPP, &mvp))
 669                 panic("Cannot find /devices");
 670 
 671         /*
 672          * Perform the mount of /devices
 673          */
 674         if (VFS_MOUNT(&devices, mvp, &mounta, CRED()))
 675                 panic("Cannot mount /devices");
 676 
 677         RUNLOCK_VFSSW();
 678 
 679         /*
 680          * Set appropriate members and add to vfs list for mnttab display
 681          */
 682         vfs_setresource(&devices, "/devices", 0);
 683         vfs_setmntpoint(&devices, "/devices", 0);
 684 
 685         /*
 686          * Hold the root of /devices so it won't go away
 687          */
 688         if (VFS_ROOT(&devices, &devicesdir))
 689                 panic("vfs_mountdevices: not devices root");
 690 
 691         if (vfs_lock(&devices) != 0) {
 692                 VN_RELE(devicesdir);
 693                 cmn_err(CE_NOTE, "Cannot acquire vfs_lock of /devices");
 694                 return;
 695         }
 696 
 697         if (vn_vfswlock(mvp) != 0) {
 698                 vfs_unlock(&devices);
 699                 VN_RELE(devicesdir);
 700                 cmn_err(CE_NOTE, "Cannot acquire vfswlock of /devices");
 701                 return;
 702         }
 703 
 704         vfs_add(mvp, &devices, 0);
 705         vn_vfsunlock(mvp);
 706         vfs_unlock(&devices);
 707         VN_RELE(devicesdir);
 708 }
 709 
 710 /*
 711  * mount the first instance of /dev  to root and remain mounted
 712  */
 713 static void
 714 vfs_mountdev1(void)
 715 {
 716         struct vfssw *vsw;
 717         struct vnode *mvp;
 718         struct mounta mounta = {        /* fake mounta for sdev_mount() */
 719                 NULL,
 720                 NULL,
 721                 MS_SYSSPACE | MS_OVERLAY,
 722                 NULL,
 723                 NULL,
 724                 0,
 725                 NULL,
 726                 0
 727         };
 728 
 729         /*
 730          * _init dev module to fill in the vfssw
 731          */
 732         if (modload("fs", "dev") == -1)
 733                 cmn_err(CE_PANIC, "Cannot _init dev module\n");
 734 
 735         /*
 736          * Hold vfs
 737          */
 738         RLOCK_VFSSW();
 739         vsw = vfs_getvfsswbyname("dev");
 740         VFS_INIT(&dev, &vsw->vsw_vfsops, NULL);
 741         VFS_HOLD(&dev);
 742 
 743         /*
 744          * Locate mount point
 745          */
 746         if (lookupname("/dev", UIO_SYSSPACE, FOLLOW, NULLVPP, &mvp))
 747                 cmn_err(CE_PANIC, "Cannot find /dev\n");
 748 
 749         /*
 750          * Perform the mount of /dev
 751          */
 752         if (VFS_MOUNT(&dev, mvp, &mounta, CRED()))
 753                 cmn_err(CE_PANIC, "Cannot mount /dev 1\n");
 754 
 755         RUNLOCK_VFSSW();
 756 
 757         /*
 758          * Set appropriate members and add to vfs list for mnttab display
 759          */
 760         vfs_setresource(&dev, "/dev", 0);
 761         vfs_setmntpoint(&dev, "/dev", 0);
 762 
 763         /*
 764          * Hold the root of /dev so it won't go away
 765          */
 766         if (VFS_ROOT(&dev, &devdir))
 767                 cmn_err(CE_PANIC, "vfs_mountdev1: not dev root");
 768 
 769         if (vfs_lock(&dev) != 0) {
 770                 VN_RELE(devdir);
 771                 cmn_err(CE_NOTE, "Cannot acquire vfs_lock of /dev");
 772                 return;
 773         }
 774 
 775         if (vn_vfswlock(mvp) != 0) {
 776                 vfs_unlock(&dev);
 777                 VN_RELE(devdir);
 778                 cmn_err(CE_NOTE, "Cannot acquire vfswlock of /dev");
 779                 return;
 780         }
 781 
 782         vfs_add(mvp, &dev, 0);
 783         vn_vfsunlock(mvp);
 784         vfs_unlock(&dev);
 785         VN_RELE(devdir);
 786 }
 787 
 788 /*
 789  * Mount required filesystem. This is done right after root is mounted.
 790  */
 791 static void
 792 vfs_mountfs(char *module, char *spec, char *path)
 793 {
 794         struct vnode *mvp;
 795         struct mounta mounta;
 796         vfs_t *vfsp;
 797 
 798         bzero(&mounta, sizeof (mounta));
 799         mounta.flags = MS_SYSSPACE | MS_DATA;
 800         mounta.fstype = module;
 801         mounta.spec = spec;
 802         mounta.dir = path;
 803         if (lookupname(path, UIO_SYSSPACE, FOLLOW, NULLVPP, &mvp)) {
 804                 cmn_err(CE_WARN, "Cannot find %s", path);
 805                 return;
 806         }
 807         if (domount(NULL, &mounta, mvp, CRED(), &vfsp))
 808                 cmn_err(CE_WARN, "Cannot mount %s", path);
 809         else
 810                 VFS_RELE(vfsp);
 811         VN_RELE(mvp);
 812 }
 813 
 814 /*
 815  * vfs_mountroot is called by main() to mount the root filesystem.
 816  */
 817 void
 818 vfs_mountroot(void)
 819 {
 820         struct vnode    *rvp = NULL;
 821         char            *path;
 822         size_t          plen;
 823         struct vfssw    *vswp;
 824         proc_t          *p;
 825 
 826         rw_init(&vfssw_lock, NULL, RW_DEFAULT, NULL);
 827         rw_init(&vfslist, NULL, RW_DEFAULT, NULL);
 828 
 829         /*
 830          * Alloc the vfs hash bucket array and locks
 831          */
 832         rvfs_list = kmem_zalloc(vfshsz * sizeof (rvfs_t), KM_SLEEP);
 833 
 834         /*
 835          * Call machine-dependent routine "rootconf" to choose a root
 836          * file system type.
 837          */
 838         if (rootconf())
 839                 panic("vfs_mountroot: cannot mount root");
 840         /*
 841          * Get vnode for '/'.  Set up rootdir, u.u_rdir and u.u_cdir
 842          * to point to it.  These are used by lookuppn() so that it
 843          * knows where to start from ('/' or '.').
 844          */
 845         vfs_setmntpoint(rootvfs, "/", 0);
 846         if (VFS_ROOT(rootvfs, &rootdir))
 847                 panic("vfs_mountroot: no root vnode");
 848 
 849         /*
 850          * At this point, the process tree consists of p0 and possibly some
 851          * direct children of p0.  (i.e. there are no grandchildren)
 852          *
 853          * Walk through them all, setting their current directory.
 854          */
 855         mutex_enter(&pidlock);
 856         for (p = practive; p != NULL; p = p->p_next) {
 857                 ASSERT(p == &p0 || p->p_parent == &p0);
 858 
 859                 PTOU(p)->u_cdir = rootdir;
 860                 VN_HOLD(PTOU(p)->u_cdir);
 861                 PTOU(p)->u_rdir = NULL;
 862         }
 863         mutex_exit(&pidlock);
 864 
 865         /*
 866          * Setup the global zone's rootvp, now that it exists.
 867          */
 868         global_zone->zone_rootvp = rootdir;
 869         VN_HOLD(global_zone->zone_rootvp);
 870 
 871         /*
 872          * Notify the module code that it can begin using the
 873          * root filesystem instead of the boot program's services.
 874          */
 875         modrootloaded = 1;
 876 
 877         /*
 878          * Special handling for a ZFS root file system.
 879          */
 880         zfs_boot_init();
 881 
 882         /*
 883          * Set up mnttab information for root
 884          */
 885         vfs_setresource(rootvfs, rootfs.bo_name, 0);
 886 
 887         /*
 888          * Notify cluster software that the root filesystem is available.
 889          */
 890         clboot_mountroot();
 891 
 892         /* Now that we're all done with the root FS, set up its vopstats */
 893         if ((vswp = vfs_getvfsswbyvfsops(vfs_getops(rootvfs))) != NULL) {
 894                 /* Set flag for statistics collection */
 895                 if (vswp->vsw_flag & VSW_STATS) {
 896                         initialize_vopstats(&rootvfs->vfs_vopstats);
 897                         rootvfs->vfs_flag |= VFS_STATS;
 898                         rootvfs->vfs_fstypevsp =
 899                             get_fstype_vopstats(rootvfs, vswp);
 900                         rootvfs->vfs_vskap = get_vskstat_anchor(rootvfs);
 901                 }
 902                 vfs_unrefvfssw(vswp);
 903         }
 904 
 905         /*
 906          * Mount /devices, /dev instance 1, /system/contract, /etc/mnttab,
 907          * /etc/svc/volatile, /etc/dfs/sharetab, /system/object, and /proc.
 908          */
 909         vfs_mountdevices();
 910         vfs_mountdev1();
 911 
 912         vfs_mountfs("ctfs", "ctfs", CTFS_ROOT);
 913         vfs_mountfs("proc", "/proc", "/proc");
 914         vfs_mountfs("mntfs", "/etc/mnttab", "/etc/mnttab");
 915         vfs_mountfs("tmpfs", "/etc/svc/volatile", "/etc/svc/volatile");
 916         vfs_mountfs("objfs", "objfs", OBJFS_ROOT);
 917         vfs_mountfs("bootfs", "bootfs", "/system/boot");
 918 
 919         if (getzoneid() == GLOBAL_ZONEID) {
 920                 vfs_mountfs("sharefs", "sharefs", "/etc/dfs/sharetab");
 921         }
 922 
 923         if (strcmp(rootfs.bo_fstype, "zfs") != 0) {
 924                 /*
 925                  * Look up the root device via devfs so that a dv_node is
 926                  * created for it. The vnode is never VN_RELE()ed.
 927                  * We allocate more than MAXPATHLEN so that the
 928                  * buffer passed to i_ddi_prompath_to_devfspath() is
 929                  * exactly MAXPATHLEN (the function expects a buffer
 930                  * of that length).
 931                  */
 932                 plen = strlen("/devices");
 933                 path = kmem_alloc(plen + MAXPATHLEN, KM_SLEEP);
 934                 (void) strcpy(path, "/devices");
 935 
 936                 if (i_ddi_prompath_to_devfspath(rootfs.bo_name, path + plen)
 937                     != DDI_SUCCESS ||
 938                     lookupname(path, UIO_SYSSPACE, FOLLOW, NULLVPP, &rvp)) {
 939 
 940                         /* NUL terminate in case "path" has garbage */
 941                         path[plen + MAXPATHLEN - 1] = '\0';
 942 #ifdef  DEBUG
 943                         cmn_err(CE_WARN, "!Cannot lookup root device: %s",
 944                             path);
 945 #endif
 946                 }
 947                 kmem_free(path, plen + MAXPATHLEN);
 948         }
 949 
 950         vfs_mnttabvp_setup();
 951 }
 952 
 953 /*
 954  * Check to see if our "block device" is actually a file.  If so,
 955  * automatically add a lofi device, and keep track of this fact.
 956  */
 957 static int
 958 lofi_add(const char *fsname, struct vfs *vfsp,
 959     mntopts_t *mntopts, struct mounta *uap)
 960 {
 961         int fromspace = (uap->flags & MS_SYSSPACE) ?
 962             UIO_SYSSPACE : UIO_USERSPACE;
 963         struct lofi_ioctl *li = NULL;
 964         struct vnode *vp = NULL;
 965         struct pathname pn = { NULL };
 966         ldi_ident_t ldi_id;
 967         ldi_handle_t ldi_hdl;
 968         vfssw_t *vfssw;
 969         int id;
 970         int err = 0;
 971 
 972         if ((vfssw = vfs_getvfssw(fsname)) == NULL)
 973                 return (0);
 974 
 975         if (!(vfssw->vsw_flag & VSW_CANLOFI)) {
 976                 vfs_unrefvfssw(vfssw);
 977                 return (0);
 978         }
 979 
 980         vfs_unrefvfssw(vfssw);
 981         vfssw = NULL;
 982 
 983         if (pn_get(uap->spec, fromspace, &pn) != 0)
 984                 return (0);
 985 
 986         if (lookupname(uap->spec, fromspace, FOLLOW, NULL, &vp) != 0)
 987                 goto out;
 988 
 989         if (vp->v_type != VREG)
 990                 goto out;
 991 
 992         /* OK, this is a lofi mount. */
 993 
 994         if ((uap->flags & (MS_REMOUNT|MS_GLOBAL)) ||
 995             vfs_optionisset_nolock(mntopts, MNTOPT_SUID, NULL) ||
 996             vfs_optionisset_nolock(mntopts, MNTOPT_SETUID, NULL) ||
 997             vfs_optionisset_nolock(mntopts, MNTOPT_DEVICES, NULL)) {
 998                 err = EINVAL;
 999                 goto out;
1000         }
1001 
1002         ldi_id = ldi_ident_from_anon();
1003         li = kmem_zalloc(sizeof (*li), KM_SLEEP);
1004         (void) strlcpy(li->li_filename, pn.pn_path, MAXPATHLEN);
1005 
1006         err = ldi_open_by_name("/dev/lofictl", FREAD | FWRITE, kcred,
1007             &ldi_hdl, ldi_id);
1008 
1009         if (err)
1010                 goto out2;
1011 
1012         err = ldi_ioctl(ldi_hdl, LOFI_MAP_FILE, (intptr_t)li,
1013             FREAD | FWRITE | FKIOCTL, kcred, &id);
1014 
1015         (void) ldi_close(ldi_hdl, FREAD | FWRITE, kcred);
1016 
1017         if (!err)
1018                 vfsp->vfs_lofi_id = id;
1019 
1020 out2:
1021         ldi_ident_release(ldi_id);
1022 out:
1023         if (li != NULL)
1024                 kmem_free(li, sizeof (*li));
1025         if (vp != NULL)
1026                 VN_RELE(vp);
1027         pn_free(&pn);
1028         return (err);
1029 }
1030 
1031 static void
1032 lofi_remove(struct vfs *vfsp)
1033 {
1034         struct lofi_ioctl *li = NULL;
1035         ldi_ident_t ldi_id;
1036         ldi_handle_t ldi_hdl;
1037         int err;
1038 
1039         if (vfsp->vfs_lofi_id == 0)
1040                 return;
1041 
1042         ldi_id = ldi_ident_from_anon();
1043 
1044         li = kmem_zalloc(sizeof (*li), KM_SLEEP);
1045         li->li_id = vfsp->vfs_lofi_id;
1046         li->li_cleanup = B_TRUE;
1047 
1048         err = ldi_open_by_name("/dev/lofictl", FREAD | FWRITE, kcred,
1049             &ldi_hdl, ldi_id);
1050 
1051         if (err)
1052                 goto out;
1053 
1054         err = ldi_ioctl(ldi_hdl, LOFI_UNMAP_FILE_MINOR, (intptr_t)li,
1055             FREAD | FWRITE | FKIOCTL, kcred, NULL);
1056 
1057         (void) ldi_close(ldi_hdl, FREAD | FWRITE, kcred);
1058 
1059         if (!err)
1060                 vfsp->vfs_lofi_id = 0;
1061 
1062 out:
1063         ldi_ident_release(ldi_id);
1064         if (li != NULL)
1065                 kmem_free(li, sizeof (*li));
1066 }
1067 
1068 /*
1069  * Common mount code.  Called from the system call entry point, from autofs,
1070  * nfsv4 trigger mounts, and from pxfs.
1071  *
1072  * Takes the effective file system type, mount arguments, the mount point
1073  * vnode, flags specifying whether the mount is a remount and whether it
1074  * should be entered into the vfs list, and credentials.  Fills in its vfspp
1075  * parameter with the mounted file system instance's vfs.
1076  *
1077  * Note that the effective file system type is specified as a string.  It may
1078  * be null, in which case it's determined from the mount arguments, and may
1079  * differ from the type specified in the mount arguments; this is a hook to
1080  * allow interposition when instantiating file system instances.
1081  *
1082  * The caller is responsible for releasing its own hold on the mount point
1083  * vp (this routine does its own hold when necessary).
1084  * Also note that for remounts, the mount point vp should be the vnode for
1085  * the root of the file system rather than the vnode that the file system
1086  * is mounted on top of.
1087  */
1088 int
1089 domount(char *fsname, struct mounta *uap, vnode_t *vp, struct cred *credp,
1090     struct vfs **vfspp)
1091 {
1092         struct vfssw    *vswp;
1093         vfsops_t        *vfsops;
1094         struct vfs      *vfsp;
1095         struct vnode    *bvp;
1096         dev_t           bdev = 0;
1097         mntopts_t       mnt_mntopts;
1098         int             error = 0;
1099         int             copyout_error = 0;
1100         int             ovflags;
1101         char            *opts = uap->optptr;
1102         char            *inargs = opts;
1103         int             optlen = uap->optlen;
1104         int             remount;
1105         int             rdonly;
1106         int             nbmand = 0;
1107         int             delmip = 0;
1108         int             addmip = 0;
1109         int             splice = ((uap->flags & MS_NOSPLICE) == 0);
1110         int             fromspace = (uap->flags & MS_SYSSPACE) ?
1111             UIO_SYSSPACE : UIO_USERSPACE;
1112         char            *resource = NULL, *mountpt = NULL;
1113         refstr_t        *oldresource, *oldmntpt;
1114         struct pathname pn, rpn;
1115         vsk_anchor_t    *vskap;
1116         char fstname[FSTYPSZ];
1117         zone_t          *zone;
1118 
1119         /*
1120          * The v_flag value for the mount point vp is permanently set
1121          * to VVFSLOCK so that no one bypasses the vn_vfs*locks routine
1122          * for mount point locking.
1123          */
1124         mutex_enter(&vp->v_lock);
1125         vp->v_flag |= VVFSLOCK;
1126         mutex_exit(&vp->v_lock);
1127 
1128         mnt_mntopts.mo_count = 0;
1129         /*
1130          * Find the ops vector to use to invoke the file system-specific mount
1131          * method.  If the fsname argument is non-NULL, use it directly.
1132          * Otherwise, dig the file system type information out of the mount
1133          * arguments.
1134          *
1135          * A side effect is to hold the vfssw entry.
1136          *
1137          * Mount arguments can be specified in several ways, which are
1138          * distinguished by flag bit settings.  The preferred way is to set
1139          * MS_OPTIONSTR, indicating an 8 argument mount with the file system
1140          * type supplied as a character string and the last two arguments
1141          * being a pointer to a character buffer and the size of the buffer.
1142          * On entry, the buffer holds a null terminated list of options; on
1143          * return, the string is the list of options the file system
1144          * recognized. If MS_DATA is set arguments five and six point to a
1145          * block of binary data which the file system interprets.
1146          * A further wrinkle is that some callers don't set MS_FSS and MS_DATA
1147          * consistently with these conventions.  To handle them, we check to
1148          * see whether the pointer to the file system name has a numeric value
1149          * less than 256.  If so, we treat it as an index.
1150          */
1151         if (fsname != NULL) {
1152                 if ((vswp = vfs_getvfssw(fsname)) == NULL) {
1153                         return (EINVAL);
1154                 }
1155         } else if (uap->flags & (MS_OPTIONSTR | MS_DATA | MS_FSS)) {
1156                 size_t n;
1157                 uint_t fstype;
1158 
1159                 fsname = fstname;
1160 
1161                 if ((fstype = (uintptr_t)uap->fstype) < 256) {
1162                         RLOCK_VFSSW();
1163                         if (fstype == 0 || fstype >= nfstype ||
1164                             !ALLOCATED_VFSSW(&vfssw[fstype])) {
1165                                 RUNLOCK_VFSSW();
1166                                 return (EINVAL);
1167                         }
1168                         (void) strcpy(fsname, vfssw[fstype].vsw_name);
1169                         RUNLOCK_VFSSW();
1170                         if ((vswp = vfs_getvfssw(fsname)) == NULL)
1171                                 return (EINVAL);
1172                 } else {
1173                         /*
1174                          * Handle either kernel or user address space.
1175                          */
1176                         if (uap->flags & MS_SYSSPACE) {
1177                                 error = copystr(uap->fstype, fsname,
1178                                     FSTYPSZ, &n);
1179                         } else {
1180                                 error = copyinstr(uap->fstype, fsname,
1181                                     FSTYPSZ, &n);
1182                         }
1183                         if (error) {
1184                                 if (error == ENAMETOOLONG)
1185                                         return (EINVAL);
1186                                 return (error);
1187                         }
1188                         if ((vswp = vfs_getvfssw(fsname)) == NULL)
1189                                 return (EINVAL);
1190                 }
1191         } else {
1192                 if ((vswp = vfs_getvfsswbyvfsops(vfs_getops(rootvfs))) == NULL)
1193                         return (EINVAL);
1194                 fsname = vswp->vsw_name;
1195         }
1196         if (!VFS_INSTALLED(vswp))
1197                 return (EINVAL);
1198 
1199         if ((error = secpolicy_fs_allowed_mount(fsname)) != 0)  {
1200                 vfs_unrefvfssw(vswp);
1201                 return (error);
1202         }
1203 
1204         vfsops = &vswp->vsw_vfsops;
1205 
1206         vfs_copyopttbl(&vswp->vsw_optproto, &mnt_mntopts);
1207         /*
1208          * Fetch mount options and parse them for generic vfs options
1209          */
1210         if (uap->flags & MS_OPTIONSTR) {
1211                 /*
1212                  * Limit the buffer size
1213                  */
1214                 if (optlen < 0 || optlen > MAX_MNTOPT_STR) {
1215                         error = EINVAL;
1216                         goto errout;
1217                 }
1218                 if ((uap->flags & MS_SYSSPACE) == 0) {
1219                         inargs = kmem_alloc(MAX_MNTOPT_STR, KM_SLEEP);
1220                         inargs[0] = '\0';
1221                         if (optlen) {
1222                                 error = copyinstr(opts, inargs, (size_t)optlen,
1223                                     NULL);
1224                                 if (error) {
1225                                         goto errout;
1226                                 }
1227                         }
1228                 }
1229                 vfs_parsemntopts(&mnt_mntopts, inargs, 0);
1230         }
1231         /*
1232          * Flag bits override the options string.
1233          */
1234         if (uap->flags & MS_REMOUNT)
1235                 vfs_setmntopt_nolock(&mnt_mntopts, MNTOPT_REMOUNT, NULL, 0, 0);
1236         if (uap->flags & MS_RDONLY)
1237                 vfs_setmntopt_nolock(&mnt_mntopts, MNTOPT_RO, NULL, 0, 0);
1238         if (uap->flags & MS_NOSUID)
1239                 vfs_setmntopt_nolock(&mnt_mntopts, MNTOPT_NOSUID, NULL, 0, 0);
1240 
1241         /*
1242          * Check if this is a remount; must be set in the option string and
1243          * the file system must support a remount option.
1244          */
1245         if (remount = vfs_optionisset_nolock(&mnt_mntopts,
1246             MNTOPT_REMOUNT, NULL)) {
1247                 if (!(vswp->vsw_flag & VSW_CANREMOUNT)) {
1248                         error = ENOTSUP;
1249                         goto errout;
1250                 }
1251                 uap->flags |= MS_REMOUNT;
1252         }
1253 
1254         /*
1255          * uap->flags and vfs_optionisset() should agree.
1256          */
1257         if (rdonly = vfs_optionisset_nolock(&mnt_mntopts, MNTOPT_RO, NULL)) {
1258                 uap->flags |= MS_RDONLY;
1259         }
1260         if (vfs_optionisset_nolock(&mnt_mntopts, MNTOPT_NOSUID, NULL)) {
1261                 uap->flags |= MS_NOSUID;
1262         }
1263         nbmand = vfs_optionisset_nolock(&mnt_mntopts, MNTOPT_NBMAND, NULL);
1264         ASSERT(splice || !remount);
1265         /*
1266          * If we are splicing the fs into the namespace,
1267          * perform mount point checks.
1268          *
1269          * We want to resolve the path for the mount point to eliminate
1270          * '.' and ".." and symlinks in mount points; we can't do the
1271          * same for the resource string, since it would turn
1272          * "/dev/dsk/c0t0d0s0" into "/devices/pci@...".  We need to do
1273          * this before grabbing vn_vfswlock(), because otherwise we
1274          * would deadlock with lookuppn().
1275          */
1276         if (splice) {
1277                 ASSERT(vp->v_count > 0);
1278 
1279                 /*
1280                  * Pick up mount point and device from appropriate space.
1281                  */
1282                 if (pn_get(uap->spec, fromspace, &pn) == 0) {
1283                         resource = kmem_alloc(pn.pn_pathlen + 1,
1284                             KM_SLEEP);
1285                         (void) strcpy(resource, pn.pn_path);
1286                         pn_free(&pn);
1287                 }
1288                 /*
1289                  * Do a lookupname prior to taking the
1290                  * writelock. Mark this as completed if
1291                  * successful for later cleanup and addition to
1292                  * the mount in progress table.
1293                  */
1294                 if ((vswp->vsw_flag & VSW_MOUNTDEV) &&
1295                     (uap->flags & MS_GLOBAL) == 0 &&
1296                     lookupname(uap->spec, fromspace,
1297                     FOLLOW, NULL, &bvp) == 0) {
1298                         addmip = 1;
1299                 }
1300 
1301                 if ((error = pn_get(uap->dir, fromspace, &pn)) == 0) {
1302                         pathname_t *pnp;
1303 
1304                         if (*pn.pn_path != '/') {
1305                                 error = EINVAL;
1306                                 pn_free(&pn);
1307                                 goto errout;
1308                         }
1309                         pn_alloc(&rpn);
1310                         /*
1311                          * Kludge to prevent autofs from deadlocking with
1312                          * itself when it calls domount().
1313                          *
1314                          * If autofs is calling, it is because it is doing
1315                          * (autofs) mounts in the process of an NFS mount.  A
1316                          * lookuppn() here would cause us to block waiting for
1317                          * said NFS mount to complete, which can't since this
1318                          * is the thread that was supposed to doing it.
1319                          */
1320                         if (fromspace == UIO_USERSPACE) {
1321                                 if ((error = lookuppn(&pn, &rpn, FOLLOW, NULL,
1322                                     NULL)) == 0) {
1323                                         pnp = &rpn;
1324                                 } else {
1325                                         /*
1326                                          * The file disappeared or otherwise
1327                                          * became inaccessible since we opened
1328                                          * it; might as well fail the mount
1329                                          * since the mount point is no longer
1330                                          * accessible.
1331                                          */
1332                                         pn_free(&rpn);
1333                                         pn_free(&pn);
1334                                         goto errout;
1335                                 }
1336                         } else {
1337                                 pnp = &pn;
1338                         }
1339                         mountpt = kmem_alloc(pnp->pn_pathlen + 1, KM_SLEEP);
1340                         (void) strcpy(mountpt, pnp->pn_path);
1341 
1342                         /*
1343                          * If the addition of the zone's rootpath
1344                          * would push us over a total path length
1345                          * of MAXPATHLEN, we fail the mount with
1346                          * ENAMETOOLONG, which is what we would have
1347                          * gotten if we were trying to perform the same
1348                          * mount in the global zone.
1349                          *
1350                          * strlen() doesn't count the trailing
1351                          * '\0', but zone_rootpathlen counts both a
1352                          * trailing '/' and the terminating '\0'.
1353                          */
1354                         if ((curproc->p_zone->zone_rootpathlen - 1 +
1355                             strlen(mountpt)) > MAXPATHLEN ||
1356                             (resource != NULL &&
1357                             (curproc->p_zone->zone_rootpathlen - 1 +
1358                             strlen(resource)) > MAXPATHLEN)) {
1359                                 error = ENAMETOOLONG;
1360                         }
1361 
1362                         pn_free(&rpn);
1363                         pn_free(&pn);
1364                 }
1365 
1366                 if (error)
1367                         goto errout;
1368 
1369                 /*
1370                  * Prevent path name resolution from proceeding past
1371                  * the mount point.
1372                  */
1373                 if (vn_vfswlock(vp) != 0) {
1374                         error = EBUSY;
1375                         goto errout;
1376                 }
1377 
1378                 /*
1379                  * Verify that it's legitimate to establish a mount on
1380                  * the prospective mount point.
1381                  */
1382                 if (vn_mountedvfs(vp) != NULL) {
1383                         /*
1384                          * The mount point lock was obtained after some
1385                          * other thread raced through and established a mount.
1386                          */
1387                         vn_vfsunlock(vp);
1388                         error = EBUSY;
1389                         goto errout;
1390                 }
1391                 if (vp->v_flag & VNOMOUNT) {
1392                         vn_vfsunlock(vp);
1393                         error = EINVAL;
1394                         goto errout;
1395                 }
1396         }
1397         if ((uap->flags & (MS_DATA | MS_OPTIONSTR)) == 0) {
1398                 uap->dataptr = NULL;
1399                 uap->datalen = 0;
1400         }
1401 
1402         /*
1403          * If this is a remount, we don't want to create a new VFS.
1404          * Instead, we pass the existing one with a remount flag.
1405          */
1406         if (remount) {
1407                 /*
1408                  * Confirm that the mount point is the root vnode of the
1409                  * file system that is being remounted.
1410                  * This can happen if the user specifies a different
1411                  * mount point directory pathname in the (re)mount command.
1412                  *
1413                  * Code below can only be reached if splice is true, so it's
1414                  * safe to do vn_vfsunlock() here.
1415                  */
1416                 if ((vp->v_flag & VROOT) == 0) {
1417                         vn_vfsunlock(vp);
1418                         error = ENOENT;
1419                         goto errout;
1420                 }
1421                 /*
1422                  * Disallow making file systems read-only unless file system
1423                  * explicitly allows it in its vfssw.  Ignore other flags.
1424                  */
1425                 if (rdonly && vn_is_readonly(vp) == 0 &&
1426                     (vswp->vsw_flag & VSW_CANRWRO) == 0) {
1427                         vn_vfsunlock(vp);
1428                         error = EINVAL;
1429                         goto errout;
1430                 }
1431                 /*
1432                  * Disallow changing the NBMAND disposition of the file
1433                  * system on remounts.
1434                  */
1435                 if ((nbmand && ((vp->v_vfsp->vfs_flag & VFS_NBMAND) == 0)) ||
1436                     (!nbmand && (vp->v_vfsp->vfs_flag & VFS_NBMAND))) {
1437                         vn_vfsunlock(vp);
1438                         error = EINVAL;
1439                         goto errout;
1440                 }
1441                 vfsp = vp->v_vfsp;
1442                 ovflags = vfsp->vfs_flag;
1443                 vfsp->vfs_flag |= VFS_REMOUNT;
1444                 vfsp->vfs_flag &= ~VFS_RDONLY;
1445         } else {
1446                 vfsp = vfs_alloc(KM_SLEEP);
1447                 VFS_INIT(vfsp, vfsops, NULL);
1448         }
1449 
1450         VFS_HOLD(vfsp);
1451 
1452         if ((error = lofi_add(fsname, vfsp, &mnt_mntopts, uap)) != 0) {
1453                 if (!remount) {
1454                         if (splice)
1455                                 vn_vfsunlock(vp);
1456                         vfs_free(vfsp);
1457                 } else {
1458                         vn_vfsunlock(vp);
1459                         VFS_RELE(vfsp);
1460                 }
1461                 goto errout;
1462         }
1463 
1464         /*
1465          * PRIV_SYS_MOUNT doesn't mean you can become root.
1466          */
1467         if (vfsp->vfs_lofi_id != 0) {
1468                 uap->flags |= MS_NOSUID;
1469                 vfs_setmntopt_nolock(&mnt_mntopts, MNTOPT_NOSUID, NULL, 0, 0);
1470         }
1471 
1472         /*
1473          * The vfs_reflock is not used anymore the code below explicitly
1474          * holds it preventing others accesing it directly.
1475          */
1476         if ((sema_tryp(&vfsp->vfs_reflock) == 0) &&
1477             !(vfsp->vfs_flag & VFS_REMOUNT))
1478                 cmn_err(CE_WARN,
1479                     "mount type %s couldn't get vfs_reflock", vswp->vsw_name);
1480 
1481         /*
1482          * Lock the vfs. If this is a remount we want to avoid spurious umount
1483          * failures that happen as a side-effect of fsflush() and other mount
1484          * and unmount operations that might be going on simultaneously and
1485          * may have locked the vfs currently. To not return EBUSY immediately
1486          * here we use vfs_lock_wait() instead vfs_lock() for the remount case.
1487          */
1488         if (!remount) {
1489                 if (error = vfs_lock(vfsp)) {
1490                         vfsp->vfs_flag = ovflags;
1491 
1492                         lofi_remove(vfsp);
1493 
1494                         if (splice)
1495                                 vn_vfsunlock(vp);
1496                         vfs_free(vfsp);
1497                         goto errout;
1498                 }
1499         } else {
1500                 vfs_lock_wait(vfsp);
1501         }
1502 
1503         /*
1504          * Add device to mount in progress table, global mounts require special
1505          * handling. It is possible that we have already done the lookupname
1506          * on a spliced, non-global fs. If so, we don't want to do it again
1507          * since we cannot do a lookupname after taking the
1508          * wlock above. This case is for a non-spliced, non-global filesystem.
1509          */
1510         if (!addmip) {
1511                 if ((vswp->vsw_flag & VSW_MOUNTDEV) &&
1512                     (uap->flags & MS_GLOBAL) == 0 &&
1513                     lookupname(uap->spec, fromspace, FOLLOW, NULL, &bvp) == 0) {
1514                         addmip = 1;
1515                 }
1516         }
1517 
1518         if (addmip) {
1519                 vnode_t *lvp = NULL;
1520 
1521                 error = vfs_get_lofi(vfsp, &lvp);
1522                 if (error > 0) {
1523                         lofi_remove(vfsp);
1524 
1525                         if (splice)
1526                                 vn_vfsunlock(vp);
1527                         vfs_unlock(vfsp);
1528 
1529                         if (remount) {
1530                                 VFS_RELE(vfsp);
1531                         } else {
1532                                 vfs_free(vfsp);
1533                         }
1534 
1535                         goto errout;
1536                 } else if (error == -1) {
1537                         bdev = bvp->v_rdev;
1538                         VN_RELE(bvp);
1539                 } else {
1540                         bdev = lvp->v_rdev;
1541                         VN_RELE(lvp);
1542                         VN_RELE(bvp);
1543                 }
1544 
1545                 vfs_addmip(bdev, vfsp);
1546                 addmip = 0;
1547                 delmip = 1;
1548         }
1549         /*
1550          * Invalidate cached entry for the mount point.
1551          */
1552         if (splice)
1553                 dnlc_purge_vp(vp);
1554 
1555         /*
1556          * If have an option string but the filesystem doesn't supply a
1557          * prototype options table, create a table with the global
1558          * options and sufficient room to accept all the options in the
1559          * string.  Then parse the passed in option string
1560          * accepting all the options in the string.  This gives us an
1561          * option table with all the proper cancel properties for the
1562          * global options.
1563          *
1564          * Filesystems that supply a prototype options table are handled
1565          * earlier in this function.
1566          */
1567         if (uap->flags & MS_OPTIONSTR) {
1568                 if (!(vswp->vsw_flag & VSW_HASPROTO)) {
1569                         mntopts_t tmp_mntopts;
1570 
1571                         tmp_mntopts.mo_count = 0;
1572                         vfs_createopttbl_extend(&tmp_mntopts, inargs,
1573                             &mnt_mntopts);
1574                         vfs_parsemntopts(&tmp_mntopts, inargs, 1);
1575                         vfs_swapopttbl_nolock(&mnt_mntopts, &tmp_mntopts);
1576                         vfs_freeopttbl(&tmp_mntopts);
1577                 }
1578         }
1579 
1580         /*
1581          * Serialize with zone state transitions.
1582          * See vfs_list_add; zone mounted into is:
1583          *      zone_find_by_path(refstr_value(vfsp->vfs_mntpt))
1584          * not the zone doing the mount (curproc->p_zone), but if we're already
1585          * inside a NGZ, then we know what zone we are.
1586          */
1587         if (INGLOBALZONE(curproc)) {
1588                 zone = zone_find_by_path(mountpt);
1589                 ASSERT(zone != NULL);
1590         } else {
1591                 zone = curproc->p_zone;
1592                 /*
1593                  * zone_find_by_path does a hold, so do one here too so that
1594                  * we can do a zone_rele after mount_completed.
1595                  */
1596                 zone_hold(zone);
1597         }
1598         mount_in_progress(zone);
1599         /*
1600          * Instantiate (or reinstantiate) the file system.  If appropriate,
1601          * splice it into the file system name space.
1602          *
1603          * We want VFS_MOUNT() to be able to override the vfs_resource
1604          * string if necessary (ie, mntfs), and also for a remount to
1605          * change the same (necessary when remounting '/' during boot).
1606          * So we set up vfs_mntpt and vfs_resource to what we think they
1607          * should be, then hand off control to VFS_MOUNT() which can
1608          * override this.
1609          *
1610          * For safety's sake, when changing vfs_resource or vfs_mntpt of
1611          * a vfs which is on the vfs list (i.e. during a remount), we must
1612          * never set those fields to NULL. Several bits of code make
1613          * assumptions that the fields are always valid.
1614          */
1615         vfs_swapopttbl(&mnt_mntopts, &vfsp->vfs_mntopts);
1616         if (remount) {
1617                 if ((oldresource = vfsp->vfs_resource) != NULL)
1618                         refstr_hold(oldresource);
1619                 if ((oldmntpt = vfsp->vfs_mntpt) != NULL)
1620                         refstr_hold(oldmntpt);
1621         }
1622         vfs_setresource(vfsp, resource, 0);
1623         vfs_setmntpoint(vfsp, mountpt, 0);
1624 
1625         /*
1626          * going to mount on this vnode, so notify.
1627          */
1628         vnevent_mountedover(vp, NULL);
1629         error = VFS_MOUNT(vfsp, vp, uap, credp);
1630 
1631         if (uap->flags & MS_RDONLY)
1632                 vfs_setmntopt(vfsp, MNTOPT_RO, NULL, 0);
1633         if (uap->flags & MS_NOSUID)
1634                 vfs_setmntopt(vfsp, MNTOPT_NOSUID, NULL, 0);
1635         if (uap->flags & MS_GLOBAL)
1636                 vfs_setmntopt(vfsp, MNTOPT_GLOBAL, NULL, 0);
1637 
1638         if (error) {
1639                 lofi_remove(vfsp);
1640 
1641                 if (remount) {
1642                         /* put back pre-remount options */
1643                         vfs_swapopttbl(&mnt_mntopts, &vfsp->vfs_mntopts);
1644                         vfs_setmntpoint(vfsp, refstr_value(oldmntpt),
1645                             VFSSP_VERBATIM);
1646                         if (oldmntpt)
1647                                 refstr_rele(oldmntpt);
1648                         vfs_setresource(vfsp, refstr_value(oldresource),
1649                             VFSSP_VERBATIM);
1650                         if (oldresource)
1651                                 refstr_rele(oldresource);
1652                         vfsp->vfs_flag = ovflags;
1653                         vfs_unlock(vfsp);
1654                         VFS_RELE(vfsp);
1655                 } else {
1656                         vfs_unlock(vfsp);
1657                         vfs_freemnttab(vfsp);
1658                         vfs_free(vfsp);
1659                 }
1660         } else {
1661                 /*
1662                  * Set the mount time to now
1663                  */
1664                 vfsp->vfs_mtime = ddi_get_time();
1665                 if (remount) {
1666                         vfsp->vfs_flag &= ~VFS_REMOUNT;
1667                         if (oldresource)
1668                                 refstr_rele(oldresource);
1669                         if (oldmntpt)
1670                                 refstr_rele(oldmntpt);
1671                 } else if (splice) {
1672                         /*
1673                          * Link vfsp into the name space at the mount
1674                          * point. Vfs_add() is responsible for
1675                          * holding the mount point which will be
1676                          * released when vfs_remove() is called.
1677                          */
1678                         vfs_add(vp, vfsp, uap->flags);
1679                 } else {
1680                         /*
1681                          * Hold the reference to file system which is
1682                          * not linked into the name space.
1683                          */
1684                         vfsp->vfs_zone = NULL;
1685                         VFS_HOLD(vfsp);
1686                         vfsp->vfs_vnodecovered = NULL;
1687                 }
1688                 /*
1689                  * Set flags for global options encountered
1690                  */
1691                 if (vfs_optionisset(vfsp, MNTOPT_RO, NULL))
1692                         vfsp->vfs_flag |= VFS_RDONLY;
1693                 else
1694                         vfsp->vfs_flag &= ~VFS_RDONLY;
1695                 if (vfs_optionisset(vfsp, MNTOPT_NOSUID, NULL)) {
1696                         vfsp->vfs_flag |= (VFS_NOSETUID|VFS_NODEVICES);
1697                 } else {
1698                         if (vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL))
1699                                 vfsp->vfs_flag |= VFS_NODEVICES;
1700                         else
1701                                 vfsp->vfs_flag &= ~VFS_NODEVICES;
1702                         if (vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL))
1703                                 vfsp->vfs_flag |= VFS_NOSETUID;
1704                         else
1705                                 vfsp->vfs_flag &= ~VFS_NOSETUID;
1706                 }
1707                 if (vfs_optionisset(vfsp, MNTOPT_NBMAND, NULL))
1708                         vfsp->vfs_flag |= VFS_NBMAND;
1709                 else
1710                         vfsp->vfs_flag &= ~VFS_NBMAND;
1711 
1712                 if (vfs_optionisset(vfsp, MNTOPT_XATTR, NULL))
1713                         vfsp->vfs_flag |= VFS_XATTR;
1714                 else
1715                         vfsp->vfs_flag &= ~VFS_XATTR;
1716 
1717                 if (vfs_optionisset(vfsp, MNTOPT_NOEXEC, NULL))
1718                         vfsp->vfs_flag |= VFS_NOEXEC;
1719                 else
1720                         vfsp->vfs_flag &= ~VFS_NOEXEC;
1721 
1722                 /*
1723                  * Now construct the output option string of options
1724                  * we recognized.
1725                  */
1726                 if (uap->flags & MS_OPTIONSTR) {
1727                         vfs_list_read_lock();
1728                         copyout_error = vfs_buildoptionstr(
1729                             &vfsp->vfs_mntopts, inargs, optlen);
1730                         vfs_list_unlock();
1731                         if (copyout_error == 0 &&
1732                             (uap->flags & MS_SYSSPACE) == 0) {
1733                                 copyout_error = copyoutstr(inargs, opts,
1734                                     optlen, NULL);
1735                         }
1736                 }
1737 
1738                 /*
1739                  * If this isn't a remount, set up the vopstats before
1740                  * anyone can touch this. We only allow spliced file
1741                  * systems (file systems which are in the namespace) to
1742                  * have the VFS_STATS flag set.
1743                  * NOTE: PxFS mounts the underlying file system with
1744                  * MS_NOSPLICE set and copies those vfs_flags to its private
1745                  * vfs structure. As a result, PxFS should never have
1746                  * the VFS_STATS flag or else we might access the vfs
1747                  * statistics-related fields prior to them being
1748                  * properly initialized.
1749                  */
1750                 if (!remount && (vswp->vsw_flag & VSW_STATS) && splice) {
1751                         initialize_vopstats(&vfsp->vfs_vopstats);
1752                         /*
1753                          * We need to set vfs_vskap to NULL because there's
1754                          * a chance it won't be set below.  This is checked
1755                          * in teardown_vopstats() so we can't have garbage.
1756                          */
1757                         vfsp->vfs_vskap = NULL;
1758                         vfsp->vfs_flag |= VFS_STATS;
1759                         vfsp->vfs_fstypevsp = get_fstype_vopstats(vfsp, vswp);
1760                 }
1761 
1762                 if (vswp->vsw_flag & VSW_XID)
1763                         vfsp->vfs_flag |= VFS_XID;
1764 
1765                 vfs_unlock(vfsp);
1766         }
1767         mount_completed(zone);
1768         zone_rele(zone);
1769         if (splice)
1770                 vn_vfsunlock(vp);
1771 
1772         if ((error == 0) && (copyout_error == 0)) {
1773                 if (!remount) {
1774                         /*
1775                          * Don't call get_vskstat_anchor() while holding
1776                          * locks since it allocates memory and calls
1777                          * VFS_STATVFS().  For NFS, the latter can generate
1778                          * an over-the-wire call.
1779                          */
1780                         vskap = get_vskstat_anchor(vfsp);
1781                         /* Only take the lock if we have something to do */
1782                         if (vskap != NULL) {
1783                                 vfs_lock_wait(vfsp);
1784                                 if (vfsp->vfs_flag & VFS_STATS) {
1785                                         vfsp->vfs_vskap = vskap;
1786                                 }
1787                                 vfs_unlock(vfsp);
1788                         }
1789                 }
1790                 /* Return vfsp to caller. */
1791                 *vfspp = vfsp;
1792         }
1793 errout:
1794         vfs_freeopttbl(&mnt_mntopts);
1795         if (resource != NULL)
1796                 kmem_free(resource, strlen(resource) + 1);
1797         if (mountpt != NULL)
1798                 kmem_free(mountpt, strlen(mountpt) + 1);
1799         /*
1800          * It is possible we errored prior to adding to mount in progress
1801          * table. Must free vnode we acquired with successful lookupname.
1802          */
1803         if (addmip)
1804                 VN_RELE(bvp);
1805         if (delmip)
1806                 vfs_delmip(vfsp);
1807         ASSERT(vswp != NULL);
1808         vfs_unrefvfssw(vswp);
1809         if (inargs != opts)
1810                 kmem_free(inargs, MAX_MNTOPT_STR);
1811         if (copyout_error) {
1812                 lofi_remove(vfsp);
1813                 VFS_RELE(vfsp);
1814                 error = copyout_error;
1815         }
1816         return (error);
1817 }
1818 
1819 static void
1820 vfs_setpath(
1821     struct vfs *vfsp,           /* vfs being updated */
1822     refstr_t **refp,            /* Ref-count string to contain the new path */
1823     const char *newpath,        /* Path to add to refp (above) */
1824     uint32_t flag)              /* flag */
1825 {
1826         size_t len;
1827         refstr_t *ref;
1828         zone_t *zone = curproc->p_zone;
1829         char *sp;
1830         int have_list_lock = 0;
1831 
1832         ASSERT(!VFS_ON_LIST(vfsp) || vfs_lock_held(vfsp));
1833 
1834         /*
1835          * New path must be less than MAXPATHLEN because mntfs
1836          * will only display up to MAXPATHLEN bytes. This is currently
1837          * safe, because domount() uses pn_get(), and other callers
1838          * similarly cap the size to fewer than MAXPATHLEN bytes.
1839          */
1840 
1841         ASSERT(strlen(newpath) < MAXPATHLEN);
1842 
1843         /* mntfs requires consistency while vfs list lock is held */
1844 
1845         if (VFS_ON_LIST(vfsp)) {
1846                 have_list_lock = 1;
1847                 vfs_list_lock();
1848         }
1849 
1850         if (*refp != NULL)
1851                 refstr_rele(*refp);
1852 
1853         /*
1854          * If we are in a non-global zone then we prefix the supplied path,
1855          * newpath, with the zone's root path, with two exceptions. The first
1856          * is where we have been explicitly directed to avoid doing so; this
1857          * will be the case following a failed remount, where the path supplied
1858          * will be a saved version which must now be restored. The second
1859          * exception is where newpath is not a pathname but a descriptive name,
1860          * e.g. "procfs".
1861          */
1862         if (zone == global_zone || (flag & VFSSP_VERBATIM) || *newpath != '/') {
1863                 ref = refstr_alloc(newpath);
1864                 goto out;
1865         }
1866 
1867         /*
1868          * Truncate the trailing '/' in the zoneroot, and merge
1869          * in the zone's rootpath with the "newpath" (resource
1870          * or mountpoint) passed in.
1871          *
1872          * The size of the required buffer is thus the size of
1873          * the buffer required for the passed-in newpath
1874          * (strlen(newpath) + 1), plus the size of the buffer
1875          * required to hold zone_rootpath (zone_rootpathlen)
1876          * minus one for one of the now-superfluous NUL
1877          * terminations, minus one for the trailing '/'.
1878          *
1879          * That gives us:
1880          *
1881          * (strlen(newpath) + 1) + zone_rootpathlen - 1 - 1
1882          *
1883          * Which is what we have below.
1884          */
1885 
1886         len = strlen(newpath) + zone->zone_rootpathlen - 1;
1887         sp = kmem_alloc(len, KM_SLEEP);
1888 
1889         /*
1890          * Copy everything including the trailing slash, which
1891          * we then overwrite with the NUL character.
1892          */
1893 
1894         (void) strcpy(sp, zone->zone_rootpath);
1895         sp[zone->zone_rootpathlen - 2] = '\0';
1896         (void) strcat(sp, newpath);
1897 
1898         ref = refstr_alloc(sp);
1899         kmem_free(sp, len);
1900 out:
1901         *refp = ref;
1902 
1903         if (have_list_lock) {
1904                 vfs_mnttab_modtimeupd();
1905                 vfs_list_unlock();
1906         }
1907 }
1908 
1909 /*
1910  * Record a mounted resource name in a vfs structure.
1911  * If vfsp is already mounted, caller must hold the vfs lock.
1912  */
1913 void
1914 vfs_setresource(struct vfs *vfsp, const char *resource, uint32_t flag)
1915 {
1916         if (resource == NULL || resource[0] == '\0')
1917                 resource = VFS_NORESOURCE;
1918         vfs_setpath(vfsp, &vfsp->vfs_resource, resource, flag);
1919 }
1920 
1921 /*
1922  * Record a mount point name in a vfs structure.
1923  * If vfsp is already mounted, caller must hold the vfs lock.
1924  */
1925 void
1926 vfs_setmntpoint(struct vfs *vfsp, const char *mntpt, uint32_t flag)
1927 {
1928         if (mntpt == NULL || mntpt[0] == '\0')
1929                 mntpt = VFS_NOMNTPT;
1930         vfs_setpath(vfsp, &vfsp->vfs_mntpt, mntpt, flag);
1931 }
1932 
1933 /* Returns the vfs_resource. Caller must call refstr_rele() when finished. */
1934 
1935 refstr_t *
1936 vfs_getresource(const struct vfs *vfsp)
1937 {
1938         refstr_t *resource;
1939 
1940         vfs_list_read_lock();
1941         resource = vfsp->vfs_resource;
1942         refstr_hold(resource);
1943         vfs_list_unlock();
1944 
1945         return (resource);
1946 }
1947 
1948 /* Returns the vfs_mntpt. Caller must call refstr_rele() when finished. */
1949 
1950 refstr_t *
1951 vfs_getmntpoint(const struct vfs *vfsp)
1952 {
1953         refstr_t *mntpt;
1954 
1955         vfs_list_read_lock();
1956         mntpt = vfsp->vfs_mntpt;
1957         refstr_hold(mntpt);
1958         vfs_list_unlock();
1959 
1960         return (mntpt);
1961 }
1962 
1963 /*
1964  * Create an empty options table with enough empty slots to hold all
1965  * The options in the options string passed as an argument.
1966  * Potentially prepend another options table.
1967  *
1968  * Note: caller is responsible for locking the vfs list, if needed,
1969  *       to protect mops.
1970  */
1971 static void
1972 vfs_createopttbl_extend(mntopts_t *mops, const char *opts,
1973     const mntopts_t *mtmpl)
1974 {
1975         const char *s = opts;
1976         uint_t count;
1977 
1978         if (opts == NULL || *opts == '\0') {
1979                 count = 0;
1980         } else {
1981                 count = 1;
1982 
1983                 /*
1984                  * Count number of options in the string
1985                  */
1986                 for (s = strchr(s, ','); s != NULL; s = strchr(s, ',')) {
1987                         count++;
1988                         s++;
1989                 }
1990         }
1991         vfs_copyopttbl_extend(mtmpl, mops, count);
1992 }
1993 
1994 /*
1995  * Create an empty options table with enough empty slots to hold all
1996  * The options in the options string passed as an argument.
1997  *
1998  * This function is *not* for general use by filesystems.
1999  *
2000  * Note: caller is responsible for locking the vfs list, if needed,
2001  *       to protect mops.
2002  */
2003 void
2004 vfs_createopttbl(mntopts_t *mops, const char *opts)
2005 {
2006         vfs_createopttbl_extend(mops, opts, NULL);
2007 }
2008 
2009 
2010 /*
2011  * Swap two mount options tables
2012  */
2013 static void
2014 vfs_swapopttbl_nolock(mntopts_t *optbl1, mntopts_t *optbl2)
2015 {
2016         uint_t tmpcnt;
2017         mntopt_t *tmplist;
2018 
2019         tmpcnt = optbl2->mo_count;
2020         tmplist = optbl2->mo_list;
2021         optbl2->mo_count = optbl1->mo_count;
2022         optbl2->mo_list = optbl1->mo_list;
2023         optbl1->mo_count = tmpcnt;
2024         optbl1->mo_list = tmplist;
2025 }
2026 
2027 static void
2028 vfs_swapopttbl(mntopts_t *optbl1, mntopts_t *optbl2)
2029 {
2030         vfs_list_lock();
2031         vfs_swapopttbl_nolock(optbl1, optbl2);
2032         vfs_mnttab_modtimeupd();
2033         vfs_list_unlock();
2034 }
2035 
2036 static char **
2037 vfs_copycancelopt_extend(char **const moc, int extend)
2038 {
2039         int i = 0;
2040         int j;
2041         char **result;
2042 
2043         if (moc != NULL) {
2044                 for (; moc[i] != NULL; i++)
2045                         /* count number of options to cancel */;
2046         }
2047 
2048         if (i + extend == 0)
2049                 return (NULL);
2050 
2051         result = kmem_alloc((i + extend + 1) * sizeof (char *), KM_SLEEP);
2052 
2053         for (j = 0; j < i; j++) {
2054                 result[j] = kmem_alloc(strlen(moc[j]) + 1, KM_SLEEP);
2055                 (void) strcpy(result[j], moc[j]);
2056         }
2057         for (; j <= i + extend; j++)
2058                 result[j] = NULL;
2059 
2060         return (result);
2061 }
2062 
2063 static void
2064 vfs_copyopt(const mntopt_t *s, mntopt_t *d)
2065 {
2066         char *sp, *dp;
2067 
2068         d->mo_flags = s->mo_flags;
2069         d->mo_data = s->mo_data;
2070         sp = s->mo_name;
2071         if (sp != NULL) {
2072                 dp = kmem_alloc(strlen(sp) + 1, KM_SLEEP);
2073                 (void) strcpy(dp, sp);
2074                 d->mo_name = dp;
2075         } else {
2076                 d->mo_name = NULL; /* should never happen */
2077         }
2078 
2079         d->mo_cancel = vfs_copycancelopt_extend(s->mo_cancel, 0);
2080 
2081         sp = s->mo_arg;
2082         if (sp != NULL) {
2083                 dp = kmem_alloc(strlen(sp) + 1, KM_SLEEP);
2084                 (void) strcpy(dp, sp);
2085                 d->mo_arg = dp;
2086         } else {
2087                 d->mo_arg = NULL;
2088         }
2089 }
2090 
2091 /*
2092  * Copy a mount options table, possibly allocating some spare
2093  * slots at the end.  It is permissible to copy_extend the NULL table.
2094  */
2095 static void
2096 vfs_copyopttbl_extend(const mntopts_t *smo, mntopts_t *dmo, int extra)
2097 {
2098         uint_t i, count;
2099         mntopt_t *motbl;
2100 
2101         /*
2102          * Clear out any existing stuff in the options table being initialized
2103          */
2104         vfs_freeopttbl(dmo);
2105         count = (smo == NULL) ? 0 : smo->mo_count;
2106         if ((count + extra) == 0)       /* nothing to do */
2107                 return;
2108         dmo->mo_count = count + extra;
2109         motbl = kmem_zalloc((count + extra) * sizeof (mntopt_t), KM_SLEEP);
2110         dmo->mo_list = motbl;
2111         for (i = 0; i < count; i++) {
2112                 vfs_copyopt(&smo->mo_list[i], &motbl[i]);
2113         }
2114         for (i = count; i < count + extra; i++) {
2115                 motbl[i].mo_flags = MO_EMPTY;
2116         }
2117 }
2118 
2119 /*
2120  * Copy a mount options table.
2121  *
2122  * This function is *not* for general use by filesystems.
2123  *
2124  * Note: caller is responsible for locking the vfs list, if needed,
2125  *       to protect smo and dmo.
2126  */
2127 void
2128 vfs_copyopttbl(const mntopts_t *smo, mntopts_t *dmo)
2129 {
2130         vfs_copyopttbl_extend(smo, dmo, 0);
2131 }
2132 
2133 static char **
2134 vfs_mergecancelopts(const mntopt_t *mop1, const mntopt_t *mop2)
2135 {
2136         int c1 = 0;
2137         int c2 = 0;
2138         char **result;
2139         char **sp1, **sp2, **dp;
2140 
2141         /*
2142          * First we count both lists of cancel options.
2143          * If either is NULL or has no elements, we return a copy of
2144          * the other.
2145          */
2146         if (mop1->mo_cancel != NULL) {
2147                 for (; mop1->mo_cancel[c1] != NULL; c1++)
2148                         /* count cancel options in mop1 */;
2149         }
2150 
2151         if (c1 == 0)
2152                 return (vfs_copycancelopt_extend(mop2->mo_cancel, 0));
2153 
2154         if (mop2->mo_cancel != NULL) {
2155                 for (; mop2->mo_cancel[c2] != NULL; c2++)
2156                         /* count cancel options in mop2 */;
2157         }
2158 
2159         result = vfs_copycancelopt_extend(mop1->mo_cancel, c2);
2160 
2161         if (c2 == 0)
2162                 return (result);
2163 
2164         /*
2165          * When we get here, we've got two sets of cancel options;
2166          * we need to merge the two sets.  We know that the result
2167          * array has "c1+c2+1" entries and in the end we might shrink
2168          * it.
2169          * Result now has a copy of the c1 entries from mop1; we'll
2170          * now lookup all the entries of mop2 in mop1 and copy it if
2171          * it is unique.
2172          * This operation is O(n^2) but it's only called once per
2173          * filesystem per duplicate option.  This is a situation
2174          * which doesn't arise with the filesystems in ON and
2175          * n is generally 1.
2176          */
2177 
2178         dp = &result[c1];
2179         for (sp2 = mop2->mo_cancel; *sp2 != NULL; sp2++) {
2180                 for (sp1 = mop1->mo_cancel; *sp1 != NULL; sp1++) {
2181                         if (strcmp(*sp1, *sp2) == 0)
2182                                 break;
2183                 }
2184                 if (*sp1 == NULL) {
2185                         /*
2186                          * Option *sp2 not found in mop1, so copy it.
2187                          * The calls to vfs_copycancelopt_extend()
2188                          * guarantee that there's enough room.
2189                          */
2190                         *dp = kmem_alloc(strlen(*sp2) + 1, KM_SLEEP);
2191                         (void) strcpy(*dp++, *sp2);
2192                 }
2193         }
2194         if (dp != &result[c1+c2]) {
2195                 size_t bytes = (dp - result + 1) * sizeof (char *);
2196                 char **nres = kmem_alloc(bytes, KM_SLEEP);
2197 
2198                 bcopy(result, nres, bytes);
2199                 kmem_free(result, (c1 + c2 + 1) * sizeof (char *));
2200                 result = nres;
2201         }
2202         return (result);
2203 }
2204 
2205 /*
2206  * Merge two mount option tables (outer and inner) into one.  This is very
2207  * similar to "merging" global variables and automatic variables in C.
2208  *
2209  * This isn't (and doesn't have to be) fast.
2210  *
2211  * This function is *not* for general use by filesystems.
2212  *
2213  * Note: caller is responsible for locking the vfs list, if needed,
2214  *       to protect omo, imo & dmo.
2215  */
2216 void
2217 vfs_mergeopttbl(const mntopts_t *omo, const mntopts_t *imo, mntopts_t *dmo)
2218 {
2219         uint_t i, count;
2220         mntopt_t *mop, *motbl;
2221         uint_t freeidx;
2222 
2223         /*
2224          * First determine how much space we need to allocate.
2225          */
2226         count = omo->mo_count;
2227         for (i = 0; i < imo->mo_count; i++) {
2228                 if (imo->mo_list[i].mo_flags & MO_EMPTY)
2229                         continue;
2230                 if (vfs_hasopt(omo, imo->mo_list[i].mo_name) == NULL)
2231                         count++;
2232         }
2233         ASSERT(count >= omo->mo_count &&
2234             count <= omo->mo_count + imo->mo_count);
2235         motbl = kmem_alloc(count * sizeof (mntopt_t), KM_SLEEP);
2236         for (i = 0; i < omo->mo_count; i++)
2237                 vfs_copyopt(&omo->mo_list[i], &motbl[i]);
2238         freeidx = omo->mo_count;
2239         for (i = 0; i < imo->mo_count; i++) {
2240                 if (imo->mo_list[i].mo_flags & MO_EMPTY)
2241                         continue;
2242                 if ((mop = vfs_hasopt(omo, imo->mo_list[i].mo_name)) != NULL) {
2243                         char **newcanp;
2244                         uint_t index = mop - omo->mo_list;
2245 
2246                         newcanp = vfs_mergecancelopts(mop, &motbl[index]);
2247 
2248                         vfs_freeopt(&motbl[index]);
2249                         vfs_copyopt(&imo->mo_list[i], &motbl[index]);
2250 
2251                         vfs_freecancelopt(motbl[index].mo_cancel);
2252                         motbl[index].mo_cancel = newcanp;
2253                 } else {
2254                         /*
2255                          * If it's a new option, just copy it over to the first
2256                          * free location.
2257                          */
2258                         vfs_copyopt(&imo->mo_list[i], &motbl[freeidx++]);
2259                 }
2260         }
2261         dmo->mo_count = count;
2262         dmo->mo_list = motbl;
2263 }
2264 
2265 /*
2266  * Functions to set and clear mount options in a mount options table.
2267  */
2268 
2269 /*
2270  * Clear a mount option, if it exists.
2271  *
2272  * The update_mnttab arg indicates whether mops is part of a vfs that is on
2273  * the vfs list.
2274  */
2275 static void
2276 vfs_clearmntopt_nolock(mntopts_t *mops, const char *opt, int update_mnttab)
2277 {
2278         struct mntopt *mop;
2279         uint_t i, count;
2280 
2281         ASSERT(!update_mnttab || RW_WRITE_HELD(&vfslist));
2282 
2283         count = mops->mo_count;
2284         for (i = 0; i < count; i++) {
2285                 mop = &mops->mo_list[i];
2286 
2287                 if (mop->mo_flags & MO_EMPTY)
2288                         continue;
2289                 if (strcmp(opt, mop->mo_name))
2290                         continue;
2291                 mop->mo_flags &= ~MO_SET;
2292                 if (mop->mo_arg != NULL) {
2293                         kmem_free(mop->mo_arg, strlen(mop->mo_arg) + 1);
2294                 }
2295                 mop->mo_arg = NULL;
2296                 if (update_mnttab)
2297                         vfs_mnttab_modtimeupd();
2298                 break;
2299         }
2300 }
2301 
2302 void
2303 vfs_clearmntopt(struct vfs *vfsp, const char *opt)
2304 {
2305         int gotlock = 0;
2306 
2307         if (VFS_ON_LIST(vfsp)) {
2308                 gotlock = 1;
2309                 vfs_list_lock();
2310         }
2311         vfs_clearmntopt_nolock(&vfsp->vfs_mntopts, opt, gotlock);
2312         if (gotlock)
2313                 vfs_list_unlock();
2314 }
2315 
2316 
2317 /*
2318  * Set a mount option on.  If it's not found in the table, it's silently
2319  * ignored.  If the option has MO_IGNORE set, it is still set unless the
2320  * VFS_NOFORCEOPT bit is set in the flags.  Also, VFS_DISPLAY/VFS_NODISPLAY flag
2321  * bits can be used to toggle the MO_NODISPLAY bit for the option.
2322  * If the VFS_CREATEOPT flag bit is set then the first option slot with
2323  * MO_EMPTY set is created as the option passed in.
2324  *
2325  * The update_mnttab arg indicates whether mops is part of a vfs that is on
2326  * the vfs list.
2327  */
2328 static void
2329 vfs_setmntopt_nolock(mntopts_t *mops, const char *opt,
2330     const char *arg, int flags, int update_mnttab)
2331 {
2332         mntopt_t *mop;
2333         uint_t i, count;
2334         char *sp;
2335 
2336         ASSERT(!update_mnttab || RW_WRITE_HELD(&vfslist));
2337 
2338         if (flags & VFS_CREATEOPT) {
2339                 if (vfs_hasopt(mops, opt) != NULL) {
2340                         flags &= ~VFS_CREATEOPT;
2341                 }
2342         }
2343         count = mops->mo_count;
2344         for (i = 0; i < count; i++) {
2345                 mop = &mops->mo_list[i];
2346 
2347                 if (mop->mo_flags & MO_EMPTY) {
2348                         if ((flags & VFS_CREATEOPT) == 0)
2349                                 continue;
2350                         sp = kmem_alloc(strlen(opt) + 1, KM_SLEEP);
2351                         (void) strcpy(sp, opt);
2352                         mop->mo_name = sp;
2353                         if (arg != NULL)
2354                                 mop->mo_flags = MO_HASVALUE;
2355                         else
2356                                 mop->mo_flags = 0;
2357                 } else if (strcmp(opt, mop->mo_name)) {
2358                         continue;
2359                 }
2360                 if ((mop->mo_flags & MO_IGNORE) && (flags & VFS_NOFORCEOPT))
2361                         break;
2362                 if (arg != NULL && (mop->mo_flags & MO_HASVALUE) != 0) {
2363                         sp = kmem_alloc(strlen(arg) + 1, KM_SLEEP);
2364                         (void) strcpy(sp, arg);
2365                 } else {
2366                         sp = NULL;
2367                 }
2368                 if (mop->mo_arg != NULL)
2369                         kmem_free(mop->mo_arg, strlen(mop->mo_arg) + 1);
2370                 mop->mo_arg = sp;
2371                 if (flags & VFS_DISPLAY)
2372                         mop->mo_flags &= ~MO_NODISPLAY;
2373                 if (flags & VFS_NODISPLAY)
2374                         mop->mo_flags |= MO_NODISPLAY;
2375                 mop->mo_flags |= MO_SET;
2376                 if (mop->mo_cancel != NULL) {
2377                         char **cp;
2378 
2379                         for (cp = mop->mo_cancel; *cp != NULL; cp++)
2380                                 vfs_clearmntopt_nolock(mops, *cp, 0);
2381                 }
2382                 if (update_mnttab)
2383                         vfs_mnttab_modtimeupd();
2384                 break;
2385         }
2386 }
2387 
2388 void
2389 vfs_setmntopt(struct vfs *vfsp, const char *opt, const char *arg, int flags)
2390 {
2391         int gotlock = 0;
2392 
2393         if (VFS_ON_LIST(vfsp)) {
2394                 gotlock = 1;
2395                 vfs_list_lock();
2396         }
2397         vfs_setmntopt_nolock(&vfsp->vfs_mntopts, opt, arg, flags, gotlock);
2398         if (gotlock)
2399                 vfs_list_unlock();
2400 }
2401 
2402 
2403 /*
2404  * Add a "tag" option to a mounted file system's options list.
2405  *
2406  * Note: caller is responsible for locking the vfs list, if needed,
2407  *       to protect mops.
2408  */
2409 static mntopt_t *
2410 vfs_addtag(mntopts_t *mops, const char *tag)
2411 {
2412         uint_t count;
2413         mntopt_t *mop, *motbl;
2414 
2415         count = mops->mo_count + 1;
2416         motbl = kmem_zalloc(count * sizeof (mntopt_t), KM_SLEEP);
2417         if (mops->mo_count) {
2418                 size_t len = (count - 1) * sizeof (mntopt_t);
2419 
2420                 bcopy(mops->mo_list, motbl, len);
2421                 kmem_free(mops->mo_list, len);
2422         }
2423         mops->mo_count = count;
2424         mops->mo_list = motbl;
2425         mop = &motbl[count - 1];
2426         mop->mo_flags = MO_TAG;
2427         mop->mo_name = kmem_alloc(strlen(tag) + 1, KM_SLEEP);
2428         (void) strcpy(mop->mo_name, tag);
2429         return (mop);
2430 }
2431 
2432 /*
2433  * Allow users to set arbitrary "tags" in a vfs's mount options.
2434  * Broader use within the kernel is discouraged.
2435  */
2436 int
2437 vfs_settag(uint_t major, uint_t minor, const char *mntpt, const char *tag,
2438     cred_t *cr)
2439 {
2440         vfs_t *vfsp;
2441         mntopts_t *mops;
2442         mntopt_t *mop;
2443         int found = 0;
2444         dev_t dev = makedevice(major, minor);
2445         int err = 0;
2446         char *buf = kmem_alloc(MAX_MNTOPT_STR, KM_SLEEP);
2447 
2448         /*
2449          * Find the desired mounted file system
2450          */
2451         vfs_list_lock();
2452         vfsp = rootvfs;
2453         do {
2454                 if (vfsp->vfs_dev == dev &&
2455                     strcmp(mntpt, refstr_value(vfsp->vfs_mntpt)) == 0) {
2456                         found = 1;
2457                         break;
2458                 }
2459                 vfsp = vfsp->vfs_next;
2460         } while (vfsp != rootvfs);
2461 
2462         if (!found) {
2463                 err = EINVAL;
2464                 goto out;
2465         }
2466         err = secpolicy_fs_config(cr, vfsp);
2467         if (err != 0)
2468                 goto out;
2469 
2470         mops = &vfsp->vfs_mntopts;
2471         /*
2472          * Add tag if it doesn't already exist
2473          */
2474         if ((mop = vfs_hasopt(mops, tag)) == NULL) {
2475                 int len;
2476 
2477                 (void) vfs_buildoptionstr(mops, buf, MAX_MNTOPT_STR);
2478                 len = strlen(buf);
2479                 if (len + strlen(tag) + 2 > MAX_MNTOPT_STR) {
2480                         err = ENAMETOOLONG;
2481                         goto out;
2482                 }
2483                 mop = vfs_addtag(mops, tag);
2484         }
2485         if ((mop->mo_flags & MO_TAG) == 0) {
2486                 err = EINVAL;
2487                 goto out;
2488         }
2489         vfs_setmntopt_nolock(mops, tag, NULL, 0, 1);
2490 out:
2491         vfs_list_unlock();
2492         kmem_free(buf, MAX_MNTOPT_STR);
2493         return (err);
2494 }
2495 
2496 /*
2497  * Allow users to remove arbitrary "tags" in a vfs's mount options.
2498  * Broader use within the kernel is discouraged.
2499  */
2500 int
2501 vfs_clrtag(uint_t major, uint_t minor, const char *mntpt, const char *tag,
2502     cred_t *cr)
2503 {
2504         vfs_t *vfsp;
2505         mntopt_t *mop;
2506         int found = 0;
2507         dev_t dev = makedevice(major, minor);
2508         int err = 0;
2509 
2510         /*
2511          * Find the desired mounted file system
2512          */
2513         vfs_list_lock();
2514         vfsp = rootvfs;
2515         do {
2516                 if (vfsp->vfs_dev == dev &&
2517                     strcmp(mntpt, refstr_value(vfsp->vfs_mntpt)) == 0) {
2518                         found = 1;
2519                         break;
2520                 }
2521                 vfsp = vfsp->vfs_next;
2522         } while (vfsp != rootvfs);
2523 
2524         if (!found) {
2525                 err = EINVAL;
2526                 goto out;
2527         }
2528         err = secpolicy_fs_config(cr, vfsp);
2529         if (err != 0)
2530                 goto out;
2531 
2532         if ((mop = vfs_hasopt(&vfsp->vfs_mntopts, tag)) == NULL) {
2533                 err = EINVAL;
2534                 goto out;
2535         }
2536         if ((mop->mo_flags & MO_TAG) == 0) {
2537                 err = EINVAL;
2538                 goto out;
2539         }
2540         vfs_clearmntopt_nolock(&vfsp->vfs_mntopts, tag, 1);
2541 out:
2542         vfs_list_unlock();
2543         return (err);
2544 }
2545 
2546 /*
2547  * Function to parse an option string and fill in a mount options table.
2548  * Unknown options are silently ignored.  The input option string is modified
2549  * by replacing separators with nulls.  If the create flag is set, options
2550  * not found in the table are just added on the fly.  The table must have
2551  * an option slot marked MO_EMPTY to add an option on the fly.
2552  *
2553  * This function is *not* for general use by filesystems.
2554  *
2555  * Note: caller is responsible for locking the vfs list, if needed,
2556  *       to protect mops..
2557  */
2558 void
2559 vfs_parsemntopts(mntopts_t *mops, char *osp, int create)
2560 {
2561         char *s = osp, *p, *nextop, *valp, *cp, *ep;
2562         int setflg = VFS_NOFORCEOPT;
2563 
2564         if (osp == NULL)
2565                 return;
2566         while (*s != '\0') {
2567                 p = strchr(s, ',');     /* find next option */
2568                 if (p == NULL) {
2569                         cp = NULL;
2570                         p = s + strlen(s);
2571                 } else {
2572                         cp = p;         /* save location of comma */
2573                         *p++ = '\0';    /* mark end and point to next option */
2574                 }
2575                 nextop = p;
2576                 p = strchr(s, '=');     /* look for value */
2577                 if (p == NULL) {
2578                         valp = NULL;    /* no value supplied */
2579                 } else {
2580                         ep = p;         /* save location of equals */
2581                         *p++ = '\0';    /* end option and point to value */
2582                         valp = p;
2583                 }
2584                 /*
2585                  * set option into options table
2586                  */
2587                 if (create)
2588                         setflg |= VFS_CREATEOPT;
2589                 vfs_setmntopt_nolock(mops, s, valp, setflg, 0);
2590                 if (cp != NULL)
2591                         *cp = ',';      /* restore the comma */
2592                 if (valp != NULL)
2593                         *ep = '=';      /* restore the equals */
2594                 s = nextop;
2595         }
2596 }
2597 
2598 /*
2599  * Function to inquire if an option exists in a mount options table.
2600  * Returns a pointer to the option if it exists, else NULL.
2601  *
2602  * This function is *not* for general use by filesystems.
2603  *
2604  * Note: caller is responsible for locking the vfs list, if needed,
2605  *       to protect mops.
2606  */
2607 struct mntopt *
2608 vfs_hasopt(const mntopts_t *mops, const char *opt)
2609 {
2610         struct mntopt *mop;
2611         uint_t i, count;
2612 
2613         count = mops->mo_count;
2614         for (i = 0; i < count; i++) {
2615                 mop = &mops->mo_list[i];
2616 
2617                 if (mop->mo_flags & MO_EMPTY)
2618                         continue;
2619                 if (strcmp(opt, mop->mo_name) == 0)
2620                         return (mop);
2621         }
2622         return (NULL);
2623 }
2624 
2625 /*
2626  * Function to inquire if an option is set in a mount options table.
2627  * Returns non-zero if set and fills in the arg pointer with a pointer to
2628  * the argument string or NULL if there is no argument string.
2629  */
2630 static int
2631 vfs_optionisset_nolock(const mntopts_t *mops, const char *opt, char **argp)
2632 {
2633         struct mntopt *mop;
2634         uint_t i, count;
2635 
2636         count = mops->mo_count;
2637         for (i = 0; i < count; i++) {
2638                 mop = &mops->mo_list[i];
2639 
2640                 if (mop->mo_flags & MO_EMPTY)
2641                         continue;
2642                 if (strcmp(opt, mop->mo_name))
2643                         continue;
2644                 if ((mop->mo_flags & MO_SET) == 0)
2645                         return (0);
2646                 if (argp != NULL && (mop->mo_flags & MO_HASVALUE) != 0)
2647                         *argp = mop->mo_arg;
2648                 return (1);
2649         }
2650         return (0);
2651 }
2652 
2653 
2654 int
2655 vfs_optionisset(const struct vfs *vfsp, const char *opt, char **argp)
2656 {
2657         int ret;
2658 
2659         vfs_list_read_lock();
2660         ret = vfs_optionisset_nolock(&vfsp->vfs_mntopts, opt, argp);
2661         vfs_list_unlock();
2662         return (ret);
2663 }
2664 
2665 
2666 /*
2667  * Construct a comma separated string of the options set in the given
2668  * mount table, return the string in the given buffer.  Return non-zero if
2669  * the buffer would overflow.
2670  *
2671  * This function is *not* for general use by filesystems.
2672  *
2673  * Note: caller is responsible for locking the vfs list, if needed,
2674  *       to protect mp.
2675  */
2676 int
2677 vfs_buildoptionstr(const mntopts_t *mp, char *buf, int len)
2678 {
2679         char *cp;
2680         uint_t i;
2681 
2682         buf[0] = '\0';
2683         cp = buf;
2684         for (i = 0; i < mp->mo_count; i++) {
2685                 struct mntopt *mop;
2686 
2687                 mop = &mp->mo_list[i];
2688                 if (mop->mo_flags & MO_SET) {
2689                         int optlen, comma = 0;
2690 
2691                         if (buf[0] != '\0')
2692                                 comma = 1;
2693                         optlen = strlen(mop->mo_name);
2694                         if (strlen(buf) + comma + optlen + 1 > len)
2695                                 goto err;
2696                         if (comma)
2697                                 *cp++ = ',';
2698                         (void) strcpy(cp, mop->mo_name);
2699                         cp += optlen;
2700                         /*
2701                          * Append option value if there is one
2702                          */
2703                         if (mop->mo_arg != NULL) {
2704                                 int arglen;
2705 
2706                                 arglen = strlen(mop->mo_arg);
2707                                 if (strlen(buf) + arglen + 2 > len)
2708                                         goto err;
2709                                 *cp++ = '=';
2710                                 (void) strcpy(cp, mop->mo_arg);
2711                                 cp += arglen;
2712                         }
2713                 }
2714         }
2715         return (0);
2716 err:
2717         return (EOVERFLOW);
2718 }
2719 
2720 static void
2721 vfs_freecancelopt(char **moc)
2722 {
2723         if (moc != NULL) {
2724                 int ccnt = 0;
2725                 char **cp;
2726 
2727                 for (cp = moc; *cp != NULL; cp++) {
2728                         kmem_free(*cp, strlen(*cp) + 1);
2729                         ccnt++;
2730                 }
2731                 kmem_free(moc, (ccnt + 1) * sizeof (char *));
2732         }
2733 }
2734 
2735 static void
2736 vfs_freeopt(mntopt_t *mop)
2737 {
2738         if (mop->mo_name != NULL)
2739                 kmem_free(mop->mo_name, strlen(mop->mo_name) + 1);
2740 
2741         vfs_freecancelopt(mop->mo_cancel);
2742 
2743         if (mop->mo_arg != NULL)
2744                 kmem_free(mop->mo_arg, strlen(mop->mo_arg) + 1);
2745 }
2746 
2747 /*
2748  * Free a mount options table
2749  *
2750  * This function is *not* for general use by filesystems.
2751  *
2752  * Note: caller is responsible for locking the vfs list, if needed,
2753  *       to protect mp.
2754  */
2755 void
2756 vfs_freeopttbl(mntopts_t *mp)
2757 {
2758         uint_t i, count;
2759 
2760         count = mp->mo_count;
2761         for (i = 0; i < count; i++) {
2762                 vfs_freeopt(&mp->mo_list[i]);
2763         }
2764         if (count) {
2765                 kmem_free(mp->mo_list, sizeof (mntopt_t) * count);
2766                 mp->mo_count = 0;
2767                 mp->mo_list = NULL;
2768         }
2769 }
2770 
2771 
2772 /* ARGSUSED */
2773 static int
2774 vfs_mntdummyread(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cred,
2775     caller_context_t *ct)
2776 {
2777         return (0);
2778 }
2779 
2780 /* ARGSUSED */
2781 static int
2782 vfs_mntdummywrite(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cred,
2783     caller_context_t *ct)
2784 {
2785         return (0);
2786 }
2787 
2788 /*
2789  * The dummy vnode is currently used only by file events notification
2790  * module which is just interested in the timestamps.
2791  */
2792 /* ARGSUSED */
2793 static int
2794 vfs_mntdummygetattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
2795     caller_context_t *ct)
2796 {
2797         bzero(vap, sizeof (vattr_t));
2798         vap->va_type = VREG;
2799         vap->va_nlink = 1;
2800         vap->va_ctime = vfs_mnttab_ctime;
2801         /*
2802          * it is ok to just copy mtime as the time will be monotonically
2803          * increasing.
2804          */
2805         vap->va_mtime = vfs_mnttab_mtime;
2806         vap->va_atime = vap->va_mtime;
2807         return (0);
2808 }
2809 
2810 static void
2811 vfs_mnttabvp_setup(void)
2812 {
2813         vnode_t *tvp;
2814         vnodeops_t *vfs_mntdummyvnops;
2815         const fs_operation_def_t mnt_dummyvnodeops_template[] = {
2816                 VOPNAME_READ,           { .vop_read = vfs_mntdummyread },
2817                 VOPNAME_WRITE,          { .vop_write = vfs_mntdummywrite },
2818                 VOPNAME_GETATTR,        { .vop_getattr = vfs_mntdummygetattr },
2819                 VOPNAME_VNEVENT,        { .vop_vnevent = fs_vnevent_support },
2820                 NULL,                   NULL
2821         };
2822 
2823         if (vn_make_ops("mnttab", mnt_dummyvnodeops_template,
2824             &vfs_mntdummyvnops) != 0) {
2825                 cmn_err(CE_WARN, "vfs_mnttabvp_setup: vn_make_ops failed");
2826                 /* Shouldn't happen, but not bad enough to panic */
2827                 return;
2828         }
2829 
2830         /*
2831          * A global dummy vnode is allocated to represent mntfs files.
2832          * The mntfs file (/etc/mnttab) can be monitored for file events
2833          * and receive an event when mnttab changes. Dummy VOP calls
2834          * will be made on this vnode. The file events notification module
2835          * intercepts this vnode and delivers relevant events.
2836          */
2837         tvp = vn_alloc(KM_SLEEP);
2838         tvp->v_flag = VNOMOUNT|VNOMAP|VNOSWAP|VNOCACHE;
2839         vn_setops(tvp, vfs_mntdummyvnops);
2840         tvp->v_type = VREG;
2841         /*
2842          * The mnt dummy ops do not reference v_data.
2843          * No other module intercepting this vnode should either.
2844          * Just set it to point to itself.
2845          */
2846         tvp->v_data = (caddr_t)tvp;
2847         tvp->v_vfsp = rootvfs;
2848         vfs_mntdummyvp = tvp;
2849 }
2850 
2851 /*
2852  * performs fake read/write ops
2853  */
2854 static void
2855 vfs_mnttab_rwop(int rw)
2856 {
2857         struct uio      uio;
2858         struct iovec    iov;
2859         char    buf[1];
2860 
2861         if (vfs_mntdummyvp == NULL)
2862                 return;
2863 
2864         bzero(&uio, sizeof (uio));
2865         bzero(&iov, sizeof (iov));
2866         iov.iov_base = buf;
2867         iov.iov_len = 0;
2868         uio.uio_iov = &iov;
2869         uio.uio_iovcnt = 1;
2870         uio.uio_loffset = 0;
2871         uio.uio_segflg = UIO_SYSSPACE;
2872         uio.uio_resid = 0;
2873         if (rw) {
2874                 (void) VOP_WRITE(vfs_mntdummyvp, &uio, 0, kcred, NULL);
2875         } else {
2876                 (void) VOP_READ(vfs_mntdummyvp, &uio, 0, kcred, NULL);
2877         }
2878 }
2879 
2880 /*
2881  * Generate a write operation.
2882  */
2883 void
2884 vfs_mnttab_writeop(void)
2885 {
2886         vfs_mnttab_rwop(1);
2887 }
2888 
2889 /*
2890  * Generate a read operation.
2891  */
2892 void
2893 vfs_mnttab_readop(void)
2894 {
2895         vfs_mnttab_rwop(0);
2896 }
2897 
2898 /*
2899  * Free any mnttab information recorded in the vfs struct.
2900  * The vfs must not be on the vfs list.
2901  */
2902 static void
2903 vfs_freemnttab(struct vfs *vfsp)
2904 {
2905         ASSERT(!VFS_ON_LIST(vfsp));
2906 
2907         /*
2908          * Free device and mount point information
2909          */
2910         if (vfsp->vfs_mntpt != NULL) {
2911                 refstr_rele(vfsp->vfs_mntpt);
2912                 vfsp->vfs_mntpt = NULL;
2913         }
2914         if (vfsp->vfs_resource != NULL) {
2915                 refstr_rele(vfsp->vfs_resource);
2916                 vfsp->vfs_resource = NULL;
2917         }
2918         /*
2919          * Now free mount options information
2920          */
2921         vfs_freeopttbl(&vfsp->vfs_mntopts);
2922 }
2923 
2924 /*
2925  * Return the last mnttab modification time
2926  */
2927 void
2928 vfs_mnttab_modtime(timespec_t *ts)
2929 {
2930         ASSERT(RW_LOCK_HELD(&vfslist));
2931         *ts = vfs_mnttab_mtime;
2932 }
2933 
2934 /*
2935  * See if mnttab is changed
2936  */
2937 void
2938 vfs_mnttab_poll(timespec_t *old, struct pollhead **phpp)
2939 {
2940         int changed;
2941 
2942         *phpp = (struct pollhead *)NULL;
2943 
2944         /*
2945          * Note: don't grab vfs list lock before accessing vfs_mnttab_mtime.
2946          * Can lead to deadlock against vfs_mnttab_modtimeupd(). It is safe
2947          * to not grab the vfs list lock because tv_sec is monotonically
2948          * increasing.
2949          */
2950 
2951         changed = (old->tv_nsec != vfs_mnttab_mtime.tv_nsec) ||
2952             (old->tv_sec != vfs_mnttab_mtime.tv_sec);
2953         if (!changed) {
2954                 *phpp = &vfs_pollhd;
2955         }
2956 }
2957 
2958 /* Provide a unique and monotonically-increasing timestamp. */
2959 void
2960 vfs_mono_time(timespec_t *ts)
2961 {
2962         static volatile hrtime_t hrt;           /* The saved time. */
2963         hrtime_t        newhrt, oldhrt;         /* For effecting the CAS. */
2964         timespec_t      newts;
2965 
2966         /*
2967          * Try gethrestime() first, but be prepared to fabricate a sensible
2968          * answer at the first sign of any trouble.
2969          */
2970         gethrestime(&newts);
2971         newhrt = ts2hrt(&newts);
2972         for (;;) {
2973                 oldhrt = hrt;
2974                 if (newhrt <= hrt)
2975                         newhrt = hrt + 1;
2976                 if (atomic_cas_64((uint64_t *)&hrt, oldhrt, newhrt) == oldhrt)
2977                         break;
2978         }
2979         hrt2ts(newhrt, ts);
2980 }
2981 
2982 /*
2983  * Update the mnttab modification time and wake up any waiters for
2984  * mnttab changes
2985  */
2986 void
2987 vfs_mnttab_modtimeupd()
2988 {
2989         hrtime_t oldhrt, newhrt;
2990 
2991         ASSERT(RW_WRITE_HELD(&vfslist));
2992         oldhrt = ts2hrt(&vfs_mnttab_mtime);
2993         gethrestime(&vfs_mnttab_mtime);
2994         newhrt = ts2hrt(&vfs_mnttab_mtime);
2995         if (oldhrt == (hrtime_t)0)
2996                 vfs_mnttab_ctime = vfs_mnttab_mtime;
2997         /*
2998          * Attempt to provide unique mtime (like uniqtime but not).
2999          */
3000         if (newhrt == oldhrt) {
3001                 newhrt++;
3002                 hrt2ts(newhrt, &vfs_mnttab_mtime);
3003         }
3004         pollwakeup(&vfs_pollhd, (short)POLLRDBAND);
3005         vfs_mnttab_writeop();
3006 }
3007 
3008 int
3009 dounmount(struct vfs *vfsp, int flag, cred_t *cr)
3010 {
3011         vnode_t *coveredvp;
3012         int error;
3013         extern void teardown_vopstats(vfs_t *);
3014 
3015         /*
3016          * Get covered vnode. This will be NULL if the vfs is not linked
3017          * into the file system name space (i.e., domount() with MNT_NOSPICE).
3018          */
3019         coveredvp = vfsp->vfs_vnodecovered;
3020         ASSERT(coveredvp == NULL || vn_vfswlock_held(coveredvp));
3021 
3022         /*
3023          * Purge all dnlc entries for this vfs.
3024          */
3025         (void) dnlc_purge_vfsp(vfsp, 0);
3026 
3027         /* For forcible umount, skip VFS_SYNC() since it may hang */
3028         if ((flag & MS_FORCE) == 0)
3029                 (void) VFS_SYNC(vfsp, 0, cr);
3030 
3031         /*
3032          * Lock the vfs to maintain fs status quo during unmount.  This
3033          * has to be done after the sync because ufs_update tries to acquire
3034          * the vfs_reflock.
3035          */
3036         vfs_lock_wait(vfsp);
3037 
3038         if (error = VFS_UNMOUNT(vfsp, flag, cr)) {
3039                 vfs_unlock(vfsp);
3040                 if (coveredvp != NULL)
3041                         vn_vfsunlock(coveredvp);
3042         } else if (coveredvp != NULL) {
3043                 teardown_vopstats(vfsp);
3044                 /*
3045                  * vfs_remove() will do a VN_RELE(vfsp->vfs_vnodecovered)
3046                  * when it frees vfsp so we do a VN_HOLD() so we can
3047                  * continue to use coveredvp afterwards.
3048                  */
3049                 VN_HOLD(coveredvp);
3050                 vfs_remove(vfsp);
3051                 vn_vfsunlock(coveredvp);
3052                 VN_RELE(coveredvp);
3053         } else {
3054                 teardown_vopstats(vfsp);
3055                 /*
3056                  * Release the reference to vfs that is not linked
3057                  * into the name space.
3058                  */
3059                 vfs_unlock(vfsp);
3060                 VFS_RELE(vfsp);
3061         }
3062         return (error);
3063 }
3064 
3065 
3066 /*
3067  * Vfs_unmountall() is called by uadmin() to unmount all
3068  * mounted file systems (except the root file system) during shutdown.
3069  * It follows the existing locking protocol when traversing the vfs list
3070  * to sync and unmount vfses. Even though there should be no
3071  * other thread running while the system is shutting down, it is prudent
3072  * to still follow the locking protocol.
3073  */
3074 void
3075 vfs_unmountall(void)
3076 {
3077         struct vfs *vfsp;
3078         struct vfs *prev_vfsp = NULL;
3079         int error;
3080 
3081         /*
3082          * Toss all dnlc entries now so that the per-vfs sync
3083          * and unmount operations don't have to slog through
3084          * a bunch of uninteresting vnodes over and over again.
3085          */
3086         dnlc_purge();
3087 
3088         vfs_list_lock();
3089         for (vfsp = rootvfs->vfs_prev; vfsp != rootvfs; vfsp = prev_vfsp) {
3090                 prev_vfsp = vfsp->vfs_prev;
3091 
3092                 if (vfs_lock(vfsp) != 0)
3093                         continue;
3094                 error = vn_vfswlock(vfsp->vfs_vnodecovered);
3095                 vfs_unlock(vfsp);
3096                 if (error)
3097                         continue;
3098 
3099                 vfs_list_unlock();
3100 
3101                 (void) VFS_SYNC(vfsp, SYNC_CLOSE, CRED());
3102                 (void) dounmount(vfsp, 0, CRED());
3103 
3104                 /*
3105                  * Since we dropped the vfslist lock above we must
3106                  * verify that next_vfsp still exists, else start over.
3107                  */
3108                 vfs_list_lock();
3109                 for (vfsp = rootvfs->vfs_prev;
3110                     vfsp != rootvfs; vfsp = vfsp->vfs_prev)
3111                         if (vfsp == prev_vfsp)
3112                                 break;
3113                 if (vfsp == rootvfs && prev_vfsp != rootvfs)
3114                         prev_vfsp = rootvfs->vfs_prev;
3115         }
3116         vfs_list_unlock();
3117 }
3118 
3119 /*
3120  * Called to add an entry to the end of the vfs mount in progress list
3121  */
3122 void
3123 vfs_addmip(dev_t dev, struct vfs *vfsp)
3124 {
3125         struct ipmnt *mipp;
3126 
3127         mipp = (struct ipmnt *)kmem_alloc(sizeof (struct ipmnt), KM_SLEEP);
3128         mipp->mip_next = NULL;
3129         mipp->mip_dev = dev;
3130         mipp->mip_vfsp = vfsp;
3131         mutex_enter(&vfs_miplist_mutex);
3132         if (vfs_miplist_end != NULL)
3133                 vfs_miplist_end->mip_next = mipp;
3134         else
3135                 vfs_miplist = mipp;
3136         vfs_miplist_end = mipp;
3137         mutex_exit(&vfs_miplist_mutex);
3138 }
3139 
3140 /*
3141  * Called to remove an entry from the mount in progress list
3142  * Either because the mount completed or it failed.
3143  */
3144 void
3145 vfs_delmip(struct vfs *vfsp)
3146 {
3147         struct ipmnt *mipp, *mipprev;
3148 
3149         mutex_enter(&vfs_miplist_mutex);
3150         mipprev = NULL;
3151         for (mipp = vfs_miplist;
3152             mipp && mipp->mip_vfsp != vfsp; mipp = mipp->mip_next) {
3153                 mipprev = mipp;
3154         }
3155         if (mipp == NULL)
3156                 return; /* shouldn't happen */
3157         if (mipp == vfs_miplist_end)
3158                 vfs_miplist_end = mipprev;
3159         if (mipprev == NULL)
3160                 vfs_miplist = mipp->mip_next;
3161         else
3162                 mipprev->mip_next = mipp->mip_next;
3163         mutex_exit(&vfs_miplist_mutex);
3164         kmem_free(mipp, sizeof (struct ipmnt));
3165 }
3166 
3167 /*
3168  * vfs_add is called by a specific filesystem's mount routine to add
3169  * the new vfs into the vfs list/hash and to cover the mounted-on vnode.
3170  * The vfs should already have been locked by the caller.
3171  *
3172  * coveredvp is NULL if this is the root.
3173  */
3174 void
3175 vfs_add(vnode_t *coveredvp, struct vfs *vfsp, int mflag)
3176 {
3177         int newflag;
3178 
3179         ASSERT(vfs_lock_held(vfsp));
3180         VFS_HOLD(vfsp);
3181         newflag = vfsp->vfs_flag;
3182         if (mflag & MS_RDONLY)
3183                 newflag |= VFS_RDONLY;
3184         else
3185                 newflag &= ~VFS_RDONLY;
3186         if (mflag & MS_NOSUID)
3187                 newflag |= (VFS_NOSETUID|VFS_NODEVICES);
3188         else
3189                 newflag &= ~(VFS_NOSETUID|VFS_NODEVICES);
3190         if (mflag & MS_NOMNTTAB)
3191                 newflag |= VFS_NOMNTTAB;
3192         else
3193                 newflag &= ~VFS_NOMNTTAB;
3194 
3195         if (coveredvp != NULL) {
3196                 ASSERT(vn_vfswlock_held(coveredvp));
3197                 coveredvp->v_vfsmountedhere = vfsp;
3198                 VN_HOLD(coveredvp);
3199         }
3200         vfsp->vfs_vnodecovered = coveredvp;
3201         vfsp->vfs_flag = newflag;
3202 
3203         vfs_list_add(vfsp);
3204 }
3205 
3206 /*
3207  * Remove a vfs from the vfs list, null out the pointer from the
3208  * covered vnode to the vfs (v_vfsmountedhere), and null out the pointer
3209  * from the vfs to the covered vnode (vfs_vnodecovered). Release the
3210  * reference to the vfs and to the covered vnode.
3211  *
3212  * Called from dounmount after it's confirmed with the file system
3213  * that the unmount is legal.
3214  */
3215 void
3216 vfs_remove(struct vfs *vfsp)
3217 {
3218         vnode_t *vp;
3219 
3220         ASSERT(vfs_lock_held(vfsp));
3221 
3222         /*
3223          * Can't unmount root.  Should never happen because fs will
3224          * be busy.
3225          */
3226         if (vfsp == rootvfs)
3227                 panic("vfs_remove: unmounting root");
3228 
3229         vfs_list_remove(vfsp);
3230 
3231         /*
3232          * Unhook from the file system name space.
3233          */
3234         vp = vfsp->vfs_vnodecovered;
3235         ASSERT(vn_vfswlock_held(vp));
3236         vp->v_vfsmountedhere = NULL;
3237         vfsp->vfs_vnodecovered = NULL;
3238         VN_RELE(vp);
3239 
3240         /*
3241          * Release lock and wakeup anybody waiting.
3242          */
3243         vfs_unlock(vfsp);
3244         VFS_RELE(vfsp);
3245 }
3246 
3247 /*
3248  * Lock a filesystem to prevent access to it while mounting,
3249  * unmounting and syncing.  Return EBUSY immediately if lock
3250  * can't be acquired.
3251  */
3252 int
3253 vfs_lock(vfs_t *vfsp)
3254 {
3255         vn_vfslocks_entry_t *vpvfsentry;
3256 
3257         vpvfsentry = vn_vfslocks_getlock(vfsp);
3258         if (rwst_tryenter(&vpvfsentry->ve_lock, RW_WRITER))
3259                 return (0);
3260 
3261         vn_vfslocks_rele(vpvfsentry);
3262         return (EBUSY);
3263 }
3264 
3265 int
3266 vfs_rlock(vfs_t *vfsp)
3267 {
3268         vn_vfslocks_entry_t *vpvfsentry;
3269 
3270         vpvfsentry = vn_vfslocks_getlock(vfsp);
3271 
3272         if (rwst_tryenter(&vpvfsentry->ve_lock, RW_READER))
3273                 return (0);
3274 
3275         vn_vfslocks_rele(vpvfsentry);
3276         return (EBUSY);
3277 }
3278 
3279 void
3280 vfs_lock_wait(vfs_t *vfsp)
3281 {
3282         vn_vfslocks_entry_t *vpvfsentry;
3283 
3284         vpvfsentry = vn_vfslocks_getlock(vfsp);
3285         rwst_enter(&vpvfsentry->ve_lock, RW_WRITER);
3286 }
3287 
3288 void
3289 vfs_rlock_wait(vfs_t *vfsp)
3290 {
3291         vn_vfslocks_entry_t *vpvfsentry;
3292 
3293         vpvfsentry = vn_vfslocks_getlock(vfsp);
3294         rwst_enter(&vpvfsentry->ve_lock, RW_READER);
3295 }
3296 
3297 /*
3298  * Unlock a locked filesystem.
3299  */
3300 void
3301 vfs_unlock(vfs_t *vfsp)
3302 {
3303         vn_vfslocks_entry_t *vpvfsentry;
3304 
3305         /*
3306          * vfs_unlock will mimic sema_v behaviour to fix 4748018.
3307          * And these changes should remain for the patch changes as it is.
3308          */
3309         if (panicstr)
3310                 return;
3311 
3312         /*
3313          * ve_refcount needs to be dropped twice here.
3314          * 1. To release refernce after a call to vfs_locks_getlock()
3315          * 2. To release the reference from the locking routines like
3316          *    vfs_rlock_wait/vfs_wlock_wait/vfs_wlock etc,.
3317          */
3318 
3319         vpvfsentry = vn_vfslocks_getlock(vfsp);
3320         vn_vfslocks_rele(vpvfsentry);
3321 
3322         rwst_exit(&vpvfsentry->ve_lock);
3323         vn_vfslocks_rele(vpvfsentry);
3324 }
3325 
3326 /*
3327  * Utility routine that allows a filesystem to construct its
3328  * fsid in "the usual way" - by munging some underlying dev_t and
3329  * the filesystem type number into the 64-bit fsid.  Note that
3330  * this implicitly relies on dev_t persistence to make filesystem
3331  * id's persistent.
3332  *
3333  * There's nothing to prevent an individual fs from constructing its
3334  * fsid in a different way, and indeed they should.
3335  *
3336  * Since we want fsids to be 32-bit quantities (so that they can be
3337  * exported identically by either 32-bit or 64-bit APIs, as well as
3338  * the fact that fsid's are "known" to NFS), we compress the device
3339  * number given down to 32-bits, and panic if that isn't possible.
3340  */
3341 void
3342 vfs_make_fsid(fsid_t *fsi, dev_t dev, int val)
3343 {
3344         if (!cmpldev((dev32_t *)&fsi->val[0], dev))
3345                 panic("device number too big for fsid!");
3346         fsi->val[1] = val;
3347 }
3348 
3349 int
3350 vfs_lock_held(vfs_t *vfsp)
3351 {
3352         int held;
3353         vn_vfslocks_entry_t *vpvfsentry;
3354 
3355         /*
3356          * vfs_lock_held will mimic sema_held behaviour
3357          * if panicstr is set. And these changes should remain
3358          * for the patch changes as it is.
3359          */
3360         if (panicstr)
3361                 return (1);
3362 
3363         vpvfsentry = vn_vfslocks_getlock(vfsp);
3364         held = rwst_lock_held(&vpvfsentry->ve_lock, RW_WRITER);
3365 
3366         vn_vfslocks_rele(vpvfsentry);
3367         return (held);
3368 }
3369 
3370 struct _kthread *
3371 vfs_lock_owner(vfs_t *vfsp)
3372 {
3373         struct _kthread *owner;
3374         vn_vfslocks_entry_t *vpvfsentry;
3375 
3376         /*
3377          * vfs_wlock_held will mimic sema_held behaviour
3378          * if panicstr is set. And these changes should remain
3379          * for the patch changes as it is.
3380          */
3381         if (panicstr)
3382                 return (NULL);
3383 
3384         vpvfsentry = vn_vfslocks_getlock(vfsp);
3385         owner = rwst_owner(&vpvfsentry->ve_lock);
3386 
3387         vn_vfslocks_rele(vpvfsentry);
3388         return (owner);
3389 }
3390 
3391 /*
3392  * vfs list locking.
3393  *
3394  * Rather than manipulate the vfslist lock directly, we abstract into lock
3395  * and unlock routines to allow the locking implementation to be changed for
3396  * clustering.
3397  *
3398  * Whenever the vfs list is modified through its hash links, the overall list
3399  * lock must be obtained before locking the relevant hash bucket.  But to see
3400  * whether a given vfs is on the list, it suffices to obtain the lock for the
3401  * hash bucket without getting the overall list lock.  (See getvfs() below.)
3402  */
3403 
3404 void
3405 vfs_list_lock()
3406 {
3407         rw_enter(&vfslist, RW_WRITER);
3408 }
3409 
3410 void
3411 vfs_list_read_lock()
3412 {
3413         rw_enter(&vfslist, RW_READER);
3414 }
3415 
3416 void
3417 vfs_list_unlock()
3418 {
3419         rw_exit(&vfslist);
3420 }
3421 
3422 /*
3423  * Low level worker routines for adding entries to and removing entries from
3424  * the vfs list.
3425  */
3426 
3427 static void
3428 vfs_hash_add(struct vfs *vfsp, int insert_at_head)
3429 {
3430         int vhno;
3431         struct vfs **hp;
3432         dev_t dev;
3433 
3434         ASSERT(RW_WRITE_HELD(&vfslist));
3435 
3436         dev = expldev(vfsp->vfs_fsid.val[0]);
3437         vhno = VFSHASH(getmajor(dev), getminor(dev));
3438 
3439         mutex_enter(&rvfs_list[vhno].rvfs_lock);
3440 
3441         /*
3442          * Link into the hash table, inserting it at the end, so that LOFS
3443          * with the same fsid as UFS (or other) file systems will not hide the
3444          * UFS.
3445          */
3446         if (insert_at_head) {
3447                 vfsp->vfs_hash = rvfs_list[vhno].rvfs_head;
3448                 rvfs_list[vhno].rvfs_head = vfsp;
3449         } else {
3450                 for (hp = &rvfs_list[vhno].rvfs_head; *hp != NULL;
3451                     hp = &(*hp)->vfs_hash)
3452                         continue;
3453                 /*
3454                  * hp now contains the address of the pointer to update
3455                  * to effect the insertion.
3456                  */
3457                 vfsp->vfs_hash = NULL;
3458                 *hp = vfsp;
3459         }
3460 
3461         rvfs_list[vhno].rvfs_len++;
3462         mutex_exit(&rvfs_list[vhno].rvfs_lock);
3463 }
3464 
3465 
3466 static void
3467 vfs_hash_remove(struct vfs *vfsp)
3468 {
3469         int vhno;
3470         struct vfs *tvfsp;
3471         dev_t dev;
3472 
3473         ASSERT(RW_WRITE_HELD(&vfslist));
3474 
3475         dev = expldev(vfsp->vfs_fsid.val[0]);
3476         vhno = VFSHASH(getmajor(dev), getminor(dev));
3477 
3478         mutex_enter(&rvfs_list[vhno].rvfs_lock);
3479 
3480         /*
3481          * Remove from hash.
3482          */
3483         if (rvfs_list[vhno].rvfs_head == vfsp) {
3484                 rvfs_list[vhno].rvfs_head = vfsp->vfs_hash;
3485                 rvfs_list[vhno].rvfs_len--;
3486                 goto foundit;
3487         }
3488         for (tvfsp = rvfs_list[vhno].rvfs_head; tvfsp != NULL;
3489             tvfsp = tvfsp->vfs_hash) {
3490                 if (tvfsp->vfs_hash == vfsp) {
3491                         tvfsp->vfs_hash = vfsp->vfs_hash;
3492                         rvfs_list[vhno].rvfs_len--;
3493                         goto foundit;
3494                 }
3495         }
3496         cmn_err(CE_WARN, "vfs_list_remove: vfs not found in hash");
3497 
3498 foundit:
3499 
3500         mutex_exit(&rvfs_list[vhno].rvfs_lock);
3501 }
3502 
3503 
3504 void
3505 vfs_list_add(struct vfs *vfsp)
3506 {
3507         zone_t *zone;
3508 
3509         /*
3510          * Typically, the vfs_t will have been created on behalf of the file
3511          * system in vfs_init, where it will have been provided with a
3512          * vfs_impl_t. This, however, might be lacking if the vfs_t was created
3513          * by an unbundled file system. We therefore check for such an example
3514          * before stamping the vfs_t with its creation time for the benefit of
3515          * mntfs.
3516          */
3517         if (vfsp->vfs_implp == NULL)
3518                 vfsimpl_setup(vfsp);
3519         vfs_mono_time(&vfsp->vfs_hrctime);
3520 
3521         /*
3522          * The zone that owns the mount is the one that performed the mount.
3523          * Note that this isn't necessarily the same as the zone mounted into.
3524          * The corresponding zone_rele_ref() will be done when the vfs_t
3525          * is being free'd.
3526          */
3527         vfsp->vfs_zone = curproc->p_zone;
3528         zone_init_ref(&vfsp->vfs_implp->vi_zone_ref);
3529         zone_hold_ref(vfsp->vfs_zone, &vfsp->vfs_implp->vi_zone_ref,
3530             ZONE_REF_VFS);
3531 
3532         /*
3533          * Find the zone mounted into, and put this mount on its vfs list.
3534          */
3535         zone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
3536         ASSERT(zone != NULL);
3537         /*
3538          * Special casing for the root vfs.  This structure is allocated
3539          * statically and hooked onto rootvfs at link time.  During the
3540          * vfs_mountroot call at system startup time, the root file system's
3541          * VFS_MOUNTROOT routine will call vfs_add with this root vfs struct
3542          * as argument.  The code below must detect and handle this special
3543          * case.  The only apparent justification for this special casing is
3544          * to ensure that the root file system appears at the head of the
3545          * list.
3546          *
3547          * XXX: I'm assuming that it's ok to do normal list locking when
3548          *      adding the entry for the root file system (this used to be
3549          *      done with no locks held).
3550          */
3551         vfs_list_lock();
3552         /*
3553          * Link into the vfs list proper.
3554          */
3555         if (vfsp == &root) {
3556                 /*
3557                  * Assert: This vfs is already on the list as its first entry.
3558                  * Thus, there's nothing to do.
3559                  */
3560                 ASSERT(rootvfs == vfsp);
3561                 /*
3562                  * Add it to the head of the global zone's vfslist.
3563                  */
3564                 ASSERT(zone == global_zone);
3565                 ASSERT(zone->zone_vfslist == NULL);
3566                 zone->zone_vfslist = vfsp;
3567         } else {
3568                 /*
3569                  * Link to end of list using vfs_prev (as rootvfs is now a
3570                  * doubly linked circular list) so list is in mount order for
3571                  * mnttab use.
3572                  */
3573                 rootvfs->vfs_prev->vfs_next = vfsp;
3574                 vfsp->vfs_prev = rootvfs->vfs_prev;
3575                 rootvfs->vfs_prev = vfsp;
3576                 vfsp->vfs_next = rootvfs;
3577 
3578                 /*
3579                  * Do it again for the zone-private list (which may be NULL).
3580                  */
3581                 if (zone->zone_vfslist == NULL) {
3582                         ASSERT(zone != global_zone);
3583                         zone->zone_vfslist = vfsp;
3584                 } else {
3585                         zone->zone_vfslist->vfs_zone_prev->vfs_zone_next = vfsp;
3586                         vfsp->vfs_zone_prev = zone->zone_vfslist->vfs_zone_prev;
3587                         zone->zone_vfslist->vfs_zone_prev = vfsp;
3588                         vfsp->vfs_zone_next = zone->zone_vfslist;
3589                 }
3590         }
3591 
3592         /*
3593          * Link into the hash table, inserting it at the end, so that LOFS
3594          * with the same fsid as UFS (or other) file systems will not hide
3595          * the UFS.
3596          */
3597         vfs_hash_add(vfsp, 0);
3598 
3599         /*
3600          * update the mnttab modification time
3601          */
3602         vfs_mnttab_modtimeupd();
3603         vfs_list_unlock();
3604         zone_rele(zone);
3605 }
3606 
3607 void
3608 vfs_list_remove(struct vfs *vfsp)
3609 {
3610         zone_t *zone;
3611 
3612         zone = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
3613         ASSERT(zone != NULL);
3614         /*
3615          * Callers are responsible for preventing attempts to unmount the
3616          * root.
3617          */
3618         ASSERT(vfsp != rootvfs);
3619 
3620         vfs_list_lock();
3621 
3622         /*
3623          * Remove from hash.
3624          */
3625         vfs_hash_remove(vfsp);
3626 
3627         /*
3628          * Remove from vfs list.
3629          */
3630         vfsp->vfs_prev->vfs_next = vfsp->vfs_next;
3631         vfsp->vfs_next->vfs_prev = vfsp->vfs_prev;
3632         vfsp->vfs_next = vfsp->vfs_prev = NULL;
3633 
3634         /*
3635          * Remove from zone-specific vfs list.
3636          */
3637         if (zone->zone_vfslist == vfsp)
3638                 zone->zone_vfslist = vfsp->vfs_zone_next;
3639 
3640         if (vfsp->vfs_zone_next == vfsp) {
3641                 ASSERT(vfsp->vfs_zone_prev == vfsp);
3642                 ASSERT(zone->zone_vfslist == vfsp);
3643                 zone->zone_vfslist = NULL;
3644         }
3645 
3646         vfsp->vfs_zone_prev->vfs_zone_next = vfsp->vfs_zone_next;
3647         vfsp->vfs_zone_next->vfs_zone_prev = vfsp->vfs_zone_prev;
3648         vfsp->vfs_zone_next = vfsp->vfs_zone_prev = NULL;
3649 
3650         /*
3651          * update the mnttab modification time
3652          */
3653         vfs_mnttab_modtimeupd();
3654         vfs_list_unlock();
3655         zone_rele(zone);
3656 }
3657 
3658 struct vfs *
3659 getvfs(fsid_t *fsid)
3660 {
3661         struct vfs *vfsp;
3662         int val0 = fsid->val[0];
3663         int val1 = fsid->val[1];
3664         dev_t dev = expldev(val0);
3665         int vhno = VFSHASH(getmajor(dev), getminor(dev));
3666         kmutex_t *hmp = &rvfs_list[vhno].rvfs_lock;
3667 
3668         mutex_enter(hmp);
3669         for (vfsp = rvfs_list[vhno].rvfs_head; vfsp; vfsp = vfsp->vfs_hash) {
3670                 if (vfsp->vfs_fsid.val[0] == val0 &&
3671                     vfsp->vfs_fsid.val[1] == val1) {
3672                         VFS_HOLD(vfsp);
3673                         mutex_exit(hmp);
3674                         return (vfsp);
3675                 }
3676         }
3677         mutex_exit(hmp);
3678         return (NULL);
3679 }
3680 
3681 /*
3682  * Search the vfs mount in progress list for a specified device/vfs entry.
3683  * Returns 0 if the first entry in the list that the device matches has the
3684  * given vfs pointer as well.  If the device matches but a different vfs
3685  * pointer is encountered in the list before the given vfs pointer then
3686  * a 1 is returned.
3687  */
3688 
3689 int
3690 vfs_devmounting(dev_t dev, struct vfs *vfsp)
3691 {
3692         int retval = 0;
3693         struct ipmnt *mipp;
3694 
3695         mutex_enter(&vfs_miplist_mutex);
3696         for (mipp = vfs_miplist; mipp != NULL; mipp = mipp->mip_next) {
3697                 if (mipp->mip_dev == dev) {
3698                         if (mipp->mip_vfsp != vfsp)
3699                                 retval = 1;
3700                         break;
3701                 }
3702         }
3703         mutex_exit(&vfs_miplist_mutex);
3704         return (retval);
3705 }
3706 
3707 /*
3708  * Search the vfs list for a specified device.  Returns 1, if entry is found
3709  * or 0 if no suitable entry is found.
3710  */
3711 
3712 int
3713 vfs_devismounted(dev_t dev)
3714 {
3715         struct vfs *vfsp;
3716         int found;
3717 
3718         vfs_list_read_lock();
3719         vfsp = rootvfs;
3720         found = 0;
3721         do {
3722                 if (vfsp->vfs_dev == dev) {
3723                         found = 1;
3724                         break;
3725                 }
3726                 vfsp = vfsp->vfs_next;
3727         } while (vfsp != rootvfs);
3728 
3729         vfs_list_unlock();
3730         return (found);
3731 }
3732 
3733 /*
3734  * Search the vfs list for a specified device.  Returns a pointer to it
3735  * or NULL if no suitable entry is found. The caller of this routine
3736  * is responsible for releasing the returned vfs pointer.
3737  */
3738 struct vfs *
3739 vfs_dev2vfsp(dev_t dev)
3740 {
3741         struct vfs *vfsp;
3742         int found;
3743 
3744         vfs_list_read_lock();
3745         vfsp = rootvfs;
3746         found = 0;
3747         do {
3748                 /*
3749                  * The following could be made more efficient by making
3750                  * the entire loop use vfs_zone_next if the call is from
3751                  * a zone.  The only callers, however, ustat(2) and
3752                  * umount2(2), don't seem to justify the added
3753                  * complexity at present.
3754                  */
3755                 if (vfsp->vfs_dev == dev &&
3756                     ZONE_PATH_VISIBLE(refstr_value(vfsp->vfs_mntpt),
3757                     curproc->p_zone)) {
3758                         VFS_HOLD(vfsp);
3759                         found = 1;
3760                         break;
3761                 }
3762                 vfsp = vfsp->vfs_next;
3763         } while (vfsp != rootvfs);
3764         vfs_list_unlock();
3765         return (found ? vfsp: NULL);
3766 }
3767 
3768 /*
3769  * Search the vfs list for a specified mntpoint.  Returns a pointer to it
3770  * or NULL if no suitable entry is found. The caller of this routine
3771  * is responsible for releasing the returned vfs pointer.
3772  *
3773  * Note that if multiple mntpoints match, the last one matching is
3774  * returned in an attempt to return the "top" mount when overlay
3775  * mounts are covering the same mount point.  This is accomplished by starting
3776  * at the end of the list and working our way backwards, stopping at the first
3777  * matching mount.
3778  */
3779 struct vfs *
3780 vfs_mntpoint2vfsp(const char *mp)
3781 {
3782         struct vfs *vfsp;
3783         struct vfs *retvfsp = NULL;
3784         zone_t *zone = curproc->p_zone;
3785         struct vfs *list;
3786 
3787         vfs_list_read_lock();
3788         if (getzoneid() == GLOBAL_ZONEID) {
3789                 /*
3790                  * The global zone may see filesystems in any zone.
3791                  */
3792                 vfsp = rootvfs->vfs_prev;
3793                 do {
3794                         if (strcmp(refstr_value(vfsp->vfs_mntpt), mp) == 0) {
3795                                 retvfsp = vfsp;
3796                                 break;
3797                         }
3798                         vfsp = vfsp->vfs_prev;
3799                 } while (vfsp != rootvfs->vfs_prev);
3800         } else if ((list = zone->zone_vfslist) != NULL) {
3801                 const char *mntpt;
3802 
3803                 vfsp = list->vfs_zone_prev;
3804                 do {
3805                         mntpt = refstr_value(vfsp->vfs_mntpt);
3806                         mntpt = ZONE_PATH_TRANSLATE(mntpt, zone);
3807                         if (strcmp(mntpt, mp) == 0) {
3808                                 retvfsp = vfsp;
3809                                 break;
3810                         }
3811                         vfsp = vfsp->vfs_zone_prev;
3812                 } while (vfsp != list->vfs_zone_prev);
3813         }
3814         if (retvfsp)
3815                 VFS_HOLD(retvfsp);
3816         vfs_list_unlock();
3817         return (retvfsp);
3818 }
3819 
3820 /*
3821  * Search the vfs list for a specified vfsops.
3822  * if vfs entry is found then return 1, else 0.
3823  */
3824 int
3825 vfs_opsinuse(vfsops_t *ops)
3826 {
3827         struct vfs *vfsp;
3828         int found;
3829 
3830         vfs_list_read_lock();
3831         vfsp = rootvfs;
3832         found = 0;
3833         do {
3834                 if (vfs_getops(vfsp) == ops) {
3835                         found = 1;
3836                         break;
3837                 }
3838                 vfsp = vfsp->vfs_next;
3839         } while (vfsp != rootvfs);
3840         vfs_list_unlock();
3841         return (found);
3842 }
3843 
3844 /*
3845  * Allocate an entry in vfssw for a file system type
3846  */
3847 struct vfssw *
3848 allocate_vfssw(const char *type)
3849 {
3850         struct vfssw *vswp;
3851 
3852         if (type[0] == '\0' || strlen(type) + 1 > _ST_FSTYPSZ) {
3853                 /*
3854                  * The vfssw table uses the empty string to identify an
3855                  * available entry; we cannot add any type which has
3856                  * a leading NUL. The string length is limited to
3857                  * the size of the st_fstype array in struct stat.
3858                  */
3859                 return (NULL);
3860         }
3861 
3862         ASSERT(VFSSW_WRITE_LOCKED());
3863         for (vswp = &vfssw[1]; vswp < &vfssw[nfstype]; vswp++)
3864                 if (!ALLOCATED_VFSSW(vswp)) {
3865                         vswp->vsw_name = kmem_alloc(strlen(type) + 1, KM_SLEEP);
3866                         (void) strcpy(vswp->vsw_name, type);
3867                         ASSERT(vswp->vsw_count == 0);
3868                         vswp->vsw_count = 1;
3869                         mutex_init(&vswp->vsw_lock, NULL, MUTEX_DEFAULT, NULL);
3870                         return (vswp);
3871                 }
3872         return (NULL);
3873 }
3874 
3875 /*
3876  * Impose additional layer of translation between vfstype names
3877  * and module names in the filesystem.
3878  */
3879 static const char *
3880 vfs_to_modname(const char *vfstype)
3881 {
3882         if (strcmp(vfstype, "proc") == 0) {
3883                 vfstype = "procfs";
3884         } else if (strcmp(vfstype, "fd") == 0) {
3885                 vfstype = "fdfs";
3886         } else if (strncmp(vfstype, "nfs", 3) == 0) {
3887                 vfstype = "nfs";
3888         }
3889 
3890         return (vfstype);
3891 }
3892 
3893 /*
3894  * Find a vfssw entry given a file system type name.
3895  * Try to autoload the filesystem if it's not found.
3896  * If it's installed, return the vfssw locked to prevent unloading.
3897  */
3898 struct vfssw *
3899 vfs_getvfssw(const char *type)
3900 {
3901         struct vfssw *vswp;
3902         const char *modname;
3903 
3904         RLOCK_VFSSW();
3905         vswp = vfs_getvfsswbyname(type);
3906         modname = vfs_to_modname(type);
3907 
3908         if (rootdir == NULL) {
3909                 /*
3910                  * If we haven't yet loaded the root file system, then our
3911                  * _init won't be called until later. Allocate vfssw entry,
3912                  * because mod_installfs won't be called.
3913                  */
3914                 if (vswp == NULL) {
3915                         RUNLOCK_VFSSW();
3916                         WLOCK_VFSSW();
3917                         if ((vswp = vfs_getvfsswbyname(type)) == NULL) {
3918                                 if ((vswp = allocate_vfssw(type)) == NULL) {
3919                                         WUNLOCK_VFSSW();
3920                                         return (NULL);
3921                                 }
3922                         }
3923                         WUNLOCK_VFSSW();
3924                         RLOCK_VFSSW();
3925                 }
3926                 if (!VFS_INSTALLED(vswp)) {
3927                         RUNLOCK_VFSSW();
3928                         (void) modloadonly("fs", modname);
3929                 } else
3930                         RUNLOCK_VFSSW();
3931                 return (vswp);
3932         }
3933 
3934         /*
3935          * Try to load the filesystem.  Before calling modload(), we drop
3936          * our lock on the VFS switch table, and pick it up after the
3937          * module is loaded.  However, there is a potential race:  the
3938          * module could be unloaded after the call to modload() completes
3939          * but before we pick up the lock and drive on.  Therefore,
3940          * we keep reloading the module until we've loaded the module
3941          * _and_ we have the lock on the VFS switch table.
3942          */
3943         while (vswp == NULL || !VFS_INSTALLED(vswp)) {
3944                 RUNLOCK_VFSSW();
3945                 if (modload("fs", modname) == -1)
3946                         return (NULL);
3947                 RLOCK_VFSSW();
3948                 if (vswp == NULL)
3949                         if ((vswp = vfs_getvfsswbyname(type)) == NULL)
3950                                 break;
3951         }
3952         RUNLOCK_VFSSW();
3953 
3954         return (vswp);
3955 }
3956 
3957 /*
3958  * Find a vfssw entry given a file system type name.
3959  */
3960 struct vfssw *
3961 vfs_getvfsswbyname(const char *type)
3962 {
3963         struct vfssw *vswp;
3964 
3965         ASSERT(VFSSW_LOCKED());
3966         if (type == NULL || *type == '\0')
3967                 return (NULL);
3968 
3969         for (vswp = &vfssw[1]; vswp < &vfssw[nfstype]; vswp++) {
3970                 if (strcmp(type, vswp->vsw_name) == 0) {
3971                         vfs_refvfssw(vswp);
3972                         return (vswp);
3973                 }
3974         }
3975 
3976         return (NULL);
3977 }
3978 
3979 /*
3980  * Find a vfssw entry given a set of vfsops.
3981  */
3982 struct vfssw *
3983 vfs_getvfsswbyvfsops(vfsops_t *vfsops)
3984 {
3985         struct vfssw *vswp;
3986 
3987         RLOCK_VFSSW();
3988         for (vswp = &vfssw[1]; vswp < &vfssw[nfstype]; vswp++) {
3989                 if (ALLOCATED_VFSSW(vswp) && &vswp->vsw_vfsops == vfsops) {
3990                         vfs_refvfssw(vswp);
3991                         RUNLOCK_VFSSW();
3992                         return (vswp);
3993                 }
3994         }
3995         RUNLOCK_VFSSW();
3996 
3997         return (NULL);
3998 }
3999 
4000 /*
4001  * Reference a vfssw entry.
4002  */
4003 void
4004 vfs_refvfssw(struct vfssw *vswp)
4005 {
4006 
4007         mutex_enter(&vswp->vsw_lock);
4008         vswp->vsw_count++;
4009         mutex_exit(&vswp->vsw_lock);
4010 }
4011 
4012 /*
4013  * Unreference a vfssw entry.
4014  */
4015 void
4016 vfs_unrefvfssw(struct vfssw *vswp)
4017 {
4018 
4019         mutex_enter(&vswp->vsw_lock);
4020         vswp->vsw_count--;
4021         mutex_exit(&vswp->vsw_lock);
4022 }
4023 
4024 static int sync_retries = 20;   /* number of retries when not making progress */
4025 static int sync_triesleft;      /* portion of sync_retries remaining */
4026 
4027 static pgcnt_t old_pgcnt, new_pgcnt;
4028 static int new_bufcnt, old_bufcnt;
4029 
4030 /*
4031  * Sync all of the mounted filesystems, and then wait for the actual i/o to
4032  * complete.  We wait by counting the number of dirty pages and buffers,
4033  * pushing them out using bio_busy() and page_busy(), and then counting again.
4034  * This routine is used during the uadmin A_SHUTDOWN code.  It should only
4035  * be used after some higher-level mechanism has quiesced the system so that
4036  * new writes are not being initiated while we are waiting for completion.
4037  *
4038  * To ensure finite running time, our algorithm uses sync_triesleft (a progress
4039  * counter used by the vfs_syncall() loop below). It is declared above so
4040  * it can be found easily in the debugger.
4041  *
4042  * The sync_triesleft counter is updated by vfs_syncall() itself.  If we make
4043  * sync_retries consecutive calls to bio_busy() and page_busy() without
4044  * decreasing either the number of dirty buffers or dirty pages below the
4045  * lowest count we have seen so far, we give up and return from vfs_syncall().
4046  *
4047  * Each loop iteration ends with a call to delay() one second to allow time for
4048  * i/o completion and to permit the user time to read our progress messages.
4049  */
4050 void
4051 vfs_syncall(void)
4052 {
4053         if (rootdir == NULL && !modrootloaded)
4054                 return; /* no filesystems have been loaded yet */
4055 
4056         printf("syncing file systems...");
4057         sync();
4058 
4059         sync_triesleft = sync_retries;
4060 
4061         old_bufcnt = new_bufcnt = INT_MAX;
4062         old_pgcnt = new_pgcnt = ULONG_MAX;
4063 
4064         while (sync_triesleft > 0) {
4065                 old_bufcnt = MIN(old_bufcnt, new_bufcnt);
4066                 old_pgcnt = MIN(old_pgcnt, new_pgcnt);
4067 
4068                 new_bufcnt = bio_busy(B_TRUE);
4069                 new_pgcnt = page_busy(B_TRUE);
4070 
4071                 if (new_bufcnt == 0 && new_pgcnt == 0)
4072                         break;
4073 
4074                 if (new_bufcnt < old_bufcnt || new_pgcnt < old_pgcnt)
4075                         sync_triesleft = sync_retries;
4076                 else
4077                         sync_triesleft--;
4078 
4079                 if (new_bufcnt)
4080                         printf(" [%d]", new_bufcnt);
4081                 if (new_pgcnt)
4082                         printf(" %lu", new_pgcnt);
4083 
4084                 delay(hz);
4085         }
4086 
4087         if (new_bufcnt != 0 || new_pgcnt != 0)
4088                 printf(" done (not all i/o completed)\n");
4089         else
4090                 printf(" done\n");
4091 
4092         delay(hz);
4093 }
4094 
4095 /*
4096  * Map VFS flags to statvfs flags.  These shouldn't really be separate
4097  * flags at all.
4098  */
4099 uint_t
4100 vf_to_stf(uint_t vf)
4101 {
4102         uint_t stf = 0;
4103 
4104         if (vf & VFS_RDONLY)
4105                 stf |= ST_RDONLY;
4106         if (vf & VFS_NOSETUID)
4107                 stf |= ST_NOSUID;
4108         if (vf & VFS_NOTRUNC)
4109                 stf |= ST_NOTRUNC;
4110 
4111         return (stf);
4112 }
4113 
4114 /*
4115  * Entries for (illegal) fstype 0.
4116  */
4117 /* ARGSUSED */
4118 int
4119 vfsstray_sync(struct vfs *vfsp, short arg, struct cred *cr)
4120 {
4121         cmn_err(CE_PANIC, "stray vfs operation");
4122         return (0);
4123 }
4124 
4125 /*
4126  * Entries for (illegal) fstype 0.
4127  */
4128 int
4129 vfsstray(void)
4130 {
4131         cmn_err(CE_PANIC, "stray vfs operation");
4132         return (0);
4133 }
4134 
4135 /*
4136  * Support for dealing with forced UFS unmount and its interaction with
4137  * LOFS. Could be used by any filesystem.
4138  * See bug 1203132.
4139  */
4140 int
4141 vfs_EIO(void)
4142 {
4143         return (EIO);
4144 }
4145 
4146 /*
4147  * We've gotta define the op for sync separately, since the compiler gets
4148  * confused if we mix and match ANSI and normal style prototypes when
4149  * a "short" argument is present and spits out a warning.
4150  */
4151 /*ARGSUSED*/
4152 int
4153 vfs_EIO_sync(struct vfs *vfsp, short arg, struct cred *cr)
4154 {
4155         return (EIO);
4156 }
4157 
4158 vfs_t EIO_vfs;
4159 vfsops_t *EIO_vfsops;
4160 
4161 /*
4162  * Called from startup() to initialize all loaded vfs's
4163  */
4164 void
4165 vfsinit(void)
4166 {
4167         struct vfssw *vswp;
4168         int error;
4169         extern int vopstats_enabled;
4170         extern void vopstats_startup();
4171 
4172         static const fs_operation_def_t EIO_vfsops_template[] = {
4173                 VFSNAME_MOUNT,          { .error = vfs_EIO },
4174                 VFSNAME_UNMOUNT,        { .error = vfs_EIO },
4175                 VFSNAME_ROOT,           { .error = vfs_EIO },
4176                 VFSNAME_STATVFS,        { .error = vfs_EIO },
4177                 VFSNAME_SYNC,           { .vfs_sync = vfs_EIO_sync },
4178                 VFSNAME_VGET,           { .error = vfs_EIO },
4179                 VFSNAME_MOUNTROOT,      { .error = vfs_EIO },
4180                 VFSNAME_FREEVFS,        { .error = vfs_EIO },
4181                 VFSNAME_VNSTATE,        { .error = vfs_EIO },
4182                 NULL, NULL
4183         };
4184 
4185         static const fs_operation_def_t stray_vfsops_template[] = {
4186                 VFSNAME_MOUNT,          { .error = vfsstray },
4187                 VFSNAME_UNMOUNT,        { .error = vfsstray },
4188                 VFSNAME_ROOT,           { .error = vfsstray },
4189                 VFSNAME_STATVFS,        { .error = vfsstray },
4190                 VFSNAME_SYNC,           { .vfs_sync = vfsstray_sync },
4191                 VFSNAME_VGET,           { .error = vfsstray },
4192                 VFSNAME_MOUNTROOT,      { .error = vfsstray },
4193                 VFSNAME_FREEVFS,        { .error = vfsstray },
4194                 VFSNAME_VNSTATE,        { .error = vfsstray },
4195                 NULL, NULL
4196         };
4197 
4198         /* Create vfs cache */
4199         vfs_cache = kmem_cache_create("vfs_cache", sizeof (struct vfs),
4200             sizeof (uintptr_t), NULL, NULL, NULL, NULL, NULL, 0);
4201 
4202         /* Initialize the vnode cache (file systems may use it during init). */
4203         vn_create_cache();
4204 
4205         /* Setup event monitor framework */
4206         fem_init();
4207 
4208         /* Initialize the dummy stray file system type. */
4209         error = vfs_setfsops(0, stray_vfsops_template, NULL);
4210 
4211         /* Initialize the dummy EIO file system. */
4212         error = vfs_makefsops(EIO_vfsops_template, &EIO_vfsops);
4213         if (error != 0) {
4214                 cmn_err(CE_WARN, "vfsinit: bad EIO vfs ops template");
4215                 /* Shouldn't happen, but not bad enough to panic */
4216         }
4217 
4218         VFS_INIT(&EIO_vfs, EIO_vfsops, (caddr_t)NULL);
4219 
4220         /*
4221          * Default EIO_vfs.vfs_flag to VFS_UNMOUNTED so a lookup
4222          * on this vfs can immediately notice it's invalid.
4223          */
4224         EIO_vfs.vfs_flag |= VFS_UNMOUNTED;
4225 
4226         /*
4227          * Call the init routines of non-loadable filesystems only.
4228          * Filesystems which are loaded as separate modules will be
4229          * initialized by the module loading code instead.
4230          */
4231 
4232         for (vswp = &vfssw[1]; vswp < &vfssw[nfstype]; vswp++) {
4233                 RLOCK_VFSSW();
4234                 if (vswp->vsw_init != NULL)
4235                         (*vswp->vsw_init)(vswp - vfssw, vswp->vsw_name);
4236                 RUNLOCK_VFSSW();
4237         }
4238 
4239         vopstats_startup();
4240 
4241         if (vopstats_enabled) {
4242                 /* EIO_vfs can collect stats, but we don't retrieve them */
4243                 initialize_vopstats(&EIO_vfs.vfs_vopstats);
4244                 EIO_vfs.vfs_fstypevsp = NULL;
4245                 EIO_vfs.vfs_vskap = NULL;
4246                 EIO_vfs.vfs_flag |= VFS_STATS;
4247         }
4248 
4249         xattr_init();
4250 
4251         reparse_point_init();
4252 }
4253 
4254 vfs_t *
4255 vfs_alloc(int kmflag)
4256 {
4257         vfs_t *vfsp;
4258 
4259         vfsp = kmem_cache_alloc(vfs_cache, kmflag);
4260 
4261         /*
4262          * Do the simplest initialization here.
4263          * Everything else gets done in vfs_init()
4264          */
4265         bzero(vfsp, sizeof (vfs_t));
4266         return (vfsp);
4267 }
4268 
4269 void
4270 vfs_free(vfs_t *vfsp)
4271 {
4272         /*
4273          * One would be tempted to assert that "vfsp->vfs_count == 0".
4274          * The problem is that this gets called out of domount() with
4275          * a partially initialized vfs and a vfs_count of 1.  This is
4276          * also called from vfs_rele() with a vfs_count of 0.  We can't
4277          * call VFS_RELE() from domount() if VFS_MOUNT() hasn't successfully
4278          * returned.  This is because VFS_MOUNT() fully initializes the
4279          * vfs structure and its associated data.  VFS_RELE() will call
4280          * VFS_FREEVFS() which may panic the system if the data structures
4281          * aren't fully initialized from a successful VFS_MOUNT()).
4282          */
4283 
4284         /* If FEM was in use, make sure everything gets cleaned up */
4285         if (vfsp->vfs_femhead) {
4286                 ASSERT(vfsp->vfs_femhead->femh_list == NULL);
4287                 mutex_destroy(&vfsp->vfs_femhead->femh_lock);
4288                 kmem_free(vfsp->vfs_femhead, sizeof (*(vfsp->vfs_femhead)));
4289                 vfsp->vfs_femhead = NULL;
4290         }
4291 
4292         if (vfsp->vfs_implp)
4293                 vfsimpl_teardown(vfsp);
4294         sema_destroy(&vfsp->vfs_reflock);
4295         kmem_cache_free(vfs_cache, vfsp);
4296 }
4297 
4298 /*
4299  * Increments the vfs reference count by one atomically.
4300  */
4301 void
4302 vfs_hold(vfs_t *vfsp)
4303 {
4304         atomic_inc_32(&vfsp->vfs_count);
4305         ASSERT(vfsp->vfs_count != 0);
4306 }
4307 
4308 /*
4309  * Decrements the vfs reference count by one atomically. When
4310  * vfs reference count becomes zero, it calls the file system
4311  * specific vfs_freevfs() to free up the resources.
4312  */
4313 void
4314 vfs_rele(vfs_t *vfsp)
4315 {
4316         ASSERT(vfsp->vfs_count != 0);
4317         if (atomic_dec_32_nv(&vfsp->vfs_count) == 0) {
4318                 VFS_FREEVFS(vfsp);
4319                 lofi_remove(vfsp);
4320                 if (vfsp->vfs_zone)
4321                         zone_rele_ref(&vfsp->vfs_implp->vi_zone_ref,
4322                             ZONE_REF_VFS);
4323                 vfs_freemnttab(vfsp);
4324                 vfs_free(vfsp);
4325         }
4326 }
4327 
4328 /*
4329  * Generic operations vector support.
4330  *
4331  * This is used to build operations vectors for both the vfs and vnode.
4332  * It's normally called only when a file system is loaded.
4333  *
4334  * There are many possible algorithms for this, including the following:
4335  *
4336  *   (1) scan the list of known operations; for each, see if the file system
4337  *       includes an entry for it, and fill it in as appropriate.
4338  *
4339  *   (2) set up defaults for all known operations.  scan the list of ops
4340  *       supplied by the file system; for each which is both supplied and
4341  *       known, fill it in.
4342  *
4343  *   (3) sort the lists of known ops & supplied ops; scan the list, filling
4344  *       in entries as we go.
4345  *
4346  * we choose (1) for simplicity, and because performance isn't critical here.
4347  * note that (2) could be sped up using a precomputed hash table on known ops.
4348  * (3) could be faster than either, but only if the lists were very large or
4349  * supplied in sorted order.
4350  *
4351  */
4352 
4353 int
4354 fs_build_vector(void *vector, int *unused_ops,
4355     const fs_operation_trans_def_t *translation,
4356     const fs_operation_def_t *operations)
4357 {
4358         int i, num_trans, num_ops, used;
4359 
4360         /*
4361          * Count the number of translations and the number of supplied
4362          * operations.
4363          */
4364 
4365         {
4366                 const fs_operation_trans_def_t *p;
4367 
4368                 for (num_trans = 0, p = translation;
4369                     p->name != NULL;
4370                     num_trans++, p++)
4371                         ;
4372         }
4373 
4374         {
4375                 const fs_operation_def_t *p;
4376 
4377                 for (num_ops = 0, p = operations;
4378                     p->name != NULL;
4379                     num_ops++, p++)
4380                         ;
4381         }
4382 
4383         /* Walk through each operation known to our caller.  There will be */
4384         /* one entry in the supplied "translation table" for each. */
4385 
4386         used = 0;
4387 
4388         for (i = 0; i < num_trans; i++) {
4389                 int j, found;
4390                 char *curname;
4391                 fs_generic_func_p result;
4392                 fs_generic_func_p *location;
4393 
4394                 curname = translation[i].name;
4395 
4396                 /* Look for a matching operation in the list supplied by the */
4397                 /* file system. */
4398 
4399                 found = 0;
4400 
4401                 for (j = 0; j < num_ops; j++) {
4402                         if (strcmp(operations[j].name, curname) == 0) {
4403                                 used++;
4404                                 found = 1;
4405                                 break;
4406                         }
4407                 }
4408 
4409                 /*
4410                  * If the file system is using a "placeholder" for default
4411                  * or error functions, grab the appropriate function out of
4412                  * the translation table.  If the file system didn't supply
4413                  * this operation at all, use the default function.
4414                  */
4415 
4416                 if (found) {
4417                         result = operations[j].func.fs_generic;
4418                         if (result == fs_default) {
4419                                 result = translation[i].defaultFunc;
4420                         } else if (result == fs_error) {
4421                                 result = translation[i].errorFunc;
4422                         } else if (result == NULL) {
4423                                 /* Null values are PROHIBITED */
4424                                 return (EINVAL);
4425                         }
4426                 } else {
4427                         result = translation[i].defaultFunc;
4428                 }
4429 
4430                 /* Now store the function into the operations vector. */
4431 
4432                 location = (fs_generic_func_p *)
4433                     (((char *)vector) + translation[i].offset);
4434 
4435                 *location = result;
4436         }
4437 
4438         *unused_ops = num_ops - used;
4439 
4440         return (0);
4441 }
4442 
4443 /* Placeholder functions, should never be called. */
4444 
4445 int
4446 fs_error(void)
4447 {
4448         cmn_err(CE_PANIC, "fs_error called");
4449         return (0);
4450 }
4451 
4452 int
4453 fs_default(void)
4454 {
4455         cmn_err(CE_PANIC, "fs_default called");
4456         return (0);
4457 }
4458 
4459 #ifdef __sparc
4460 
4461 /*
4462  * Part of the implementation of booting off a mirrored root
4463  * involves a change of dev_t for the root device.  To
4464  * accomplish this, first remove the existing hash table
4465  * entry for the root device, convert to the new dev_t,
4466  * then re-insert in the hash table at the head of the list.
4467  */
4468 void
4469 vfs_root_redev(vfs_t *vfsp, dev_t ndev, int fstype)
4470 {
4471         vfs_list_lock();
4472 
4473         vfs_hash_remove(vfsp);
4474 
4475         vfsp->vfs_dev = ndev;
4476         vfs_make_fsid(&vfsp->vfs_fsid, ndev, fstype);
4477 
4478         vfs_hash_add(vfsp, 1);
4479 
4480         vfs_list_unlock();
4481 }
4482 
4483 #else /* x86 NEWBOOT */
4484 
4485 #if defined(__x86)
4486 extern int hvmboot_rootconf();
4487 #endif /* __x86 */
4488 
4489 extern ib_boot_prop_t *iscsiboot_prop;
4490 
4491 int
4492 rootconf()
4493 {
4494         int error;
4495         struct vfssw *vsw;
4496         extern void pm_init();
4497         char *fstyp, *fsmod;
4498         int ret = -1;
4499 
4500         getrootfs(&fstyp, &fsmod);
4501 
4502 #if defined(__x86)
4503         /*
4504          * hvmboot_rootconf() is defined in the hvm_bootstrap misc module,
4505          * which lives in /platform/i86hvm, and hence is only available when
4506          * booted in an x86 hvm environment.  If the hvm_bootstrap misc module
4507          * is not available then the modstub for this function will return 0.
4508          * If the hvm_bootstrap misc module is available it will be loaded
4509          * and hvmboot_rootconf() will be invoked.
4510          */
4511         if (error = hvmboot_rootconf())
4512                 return (error);
4513 #endif /* __x86 */
4514 
4515         if (error = clboot_rootconf())
4516                 return (error);
4517 
4518         if (modload("fs", fsmod) == -1)
4519                 panic("Cannot _init %s module", fsmod);
4520 
4521         RLOCK_VFSSW();
4522         vsw = vfs_getvfsswbyname(fstyp);
4523         RUNLOCK_VFSSW();
4524         if (vsw == NULL) {
4525                 cmn_err(CE_CONT, "Cannot find %s filesystem\n", fstyp);
4526                 return (ENXIO);
4527         }
4528         VFS_INIT(rootvfs, &vsw->vsw_vfsops, 0);
4529         VFS_HOLD(rootvfs);
4530 
4531         /* always mount readonly first */
4532         rootvfs->vfs_flag |= VFS_RDONLY;
4533 
4534         pm_init();
4535 
4536         if (netboot && iscsiboot_prop) {
4537                 cmn_err(CE_WARN, "NFS boot and iSCSI boot"
4538                     " shouldn't happen in the same time");
4539                 return (EINVAL);
4540         }
4541 
4542         if (netboot || iscsiboot_prop) {
4543                 ret = strplumb();
4544                 if (ret != 0) {
4545                         cmn_err(CE_WARN, "Cannot plumb network device %d", ret);
4546                         return (EFAULT);
4547                 }
4548         }
4549 
4550         if ((ret == 0) && iscsiboot_prop) {
4551                 ret = modload("drv", "iscsi");
4552                 /* -1 indicates fail */
4553                 if (ret == -1) {
4554                         cmn_err(CE_WARN, "Failed to load iscsi module");
4555                         iscsi_boot_prop_free();
4556                         return (EINVAL);
4557                 } else {
4558                         if (!i_ddi_attach_pseudo_node("iscsi")) {
4559                                 cmn_err(CE_WARN,
4560                                     "Failed to attach iscsi driver");
4561                                 iscsi_boot_prop_free();
4562                                 return (ENODEV);
4563                         }
4564                 }
4565         }
4566 
4567         error = VFS_MOUNTROOT(rootvfs, ROOT_INIT);
4568         vfs_unrefvfssw(vsw);
4569         rootdev = rootvfs->vfs_dev;
4570 
4571         if (error)
4572                 cmn_err(CE_CONT, "Cannot mount root on %s fstype %s\n",
4573                     rootfs.bo_name, fstyp);
4574         else
4575                 cmn_err(CE_CONT, "?root on %s fstype %s\n",
4576                     rootfs.bo_name, fstyp);
4577         return (error);
4578 }
4579 
4580 /*
4581  * XXX this is called by nfs only and should probably be removed
4582  * If booted with ASKNAME, prompt on the console for a filesystem
4583  * name and return it.
4584  */
4585 void
4586 getfsname(char *askfor, char *name, size_t namelen)
4587 {
4588         if (boothowto & RB_ASKNAME) {
4589                 printf("%s name: ", askfor);
4590                 console_gets(name, namelen);
4591         }
4592 }
4593 
4594 /*
4595  * Init the root filesystem type (rootfs.bo_fstype) from the "fstype"
4596  * property.
4597  *
4598  * Filesystem types starting with the prefix "nfs" are diskless clients;
4599  * init the root filename name (rootfs.bo_name), too.
4600  *
4601  * If we are booting via NFS we currently have these options:
4602  *      nfs -   dynamically choose NFS V2, V3, or V4 (default)
4603  *      nfs2 -  force NFS V2
4604  *      nfs3 -  force NFS V3
4605  *      nfs4 -  force NFS V4
4606  * Because we need to maintain backward compatibility with the naming
4607  * convention that the NFS V2 filesystem name is "nfs" (see vfs_conf.c)
4608  * we need to map "nfs" => "nfsdyn" and "nfs2" => "nfs".  The dynamic
4609  * nfs module will map the type back to either "nfs", "nfs3", or "nfs4".
4610  * This is only for root filesystems, all other uses will expect
4611  * that "nfs" == NFS V2.
4612  */
4613 static void
4614 getrootfs(char **fstypp, char **fsmodp)
4615 {
4616         char *propstr = NULL;
4617 
4618         /*
4619          * Check fstype property; for diskless it should be one of "nfs",
4620          * "nfs2", "nfs3" or "nfs4".
4621          */
4622         if (ddi_prop_lookup_string(DDI_DEV_T_ANY, ddi_root_node(),
4623             DDI_PROP_DONTPASS, "fstype", &propstr)
4624             == DDI_SUCCESS) {
4625                 (void) strncpy(rootfs.bo_fstype, propstr, BO_MAXFSNAME);
4626                 ddi_prop_free(propstr);
4627 
4628         /*
4629          * if the boot property 'fstype' is not set, but 'zfs-bootfs' is set,
4630          * assume the type of this root filesystem is 'zfs'.
4631          */
4632         } else if (ddi_prop_lookup_string(DDI_DEV_T_ANY, ddi_root_node(),
4633             DDI_PROP_DONTPASS, "zfs-bootfs", &propstr)
4634             == DDI_SUCCESS) {
4635                 (void) strncpy(rootfs.bo_fstype, "zfs", BO_MAXFSNAME);
4636                 ddi_prop_free(propstr);
4637         }
4638 
4639         if (strncmp(rootfs.bo_fstype, "nfs", 3) != 0) {
4640                 *fstypp = *fsmodp = rootfs.bo_fstype;
4641                 return;
4642         }
4643 
4644         ++netboot;
4645 
4646         if (strcmp(rootfs.bo_fstype, "nfs2") == 0)
4647                 (void) strcpy(rootfs.bo_fstype, "nfs");
4648         else if (strcmp(rootfs.bo_fstype, "nfs") == 0)
4649                 (void) strcpy(rootfs.bo_fstype, "nfsdyn");
4650 
4651         /*
4652          * check if path to network interface is specified in bootpath
4653          * or by a hypervisor domain configuration file.
4654          * XXPV - enable strlumb_get_netdev_path()
4655          */
4656         if (ddi_prop_exists(DDI_DEV_T_ANY, ddi_root_node(), DDI_PROP_DONTPASS,
4657             "xpv-nfsroot")) {
4658                 (void) strcpy(rootfs.bo_name, "/xpvd/xnf@0");
4659         } else if (ddi_prop_lookup_string(DDI_DEV_T_ANY, ddi_root_node(),
4660             DDI_PROP_DONTPASS, "bootpath", &propstr)
4661             == DDI_SUCCESS) {
4662                 (void) strncpy(rootfs.bo_name, propstr, BO_MAXOBJNAME);
4663                 ddi_prop_free(propstr);
4664         } else {
4665                 rootfs.bo_name[0] = '\0';
4666         }
4667         *fstypp = rootfs.bo_fstype;
4668         *fsmodp = "nfs";
4669 }
4670 #endif
4671 
4672 /*
4673  * VFS feature routines
4674  */
4675 
4676 #define VFTINDEX(feature)       (((feature) >> 32) & 0xFFFFFFFF)
4677 #define VFTBITS(feature)        ((feature) & 0xFFFFFFFFLL)
4678 
4679 /* Register a feature in the vfs */
4680 void
4681 vfs_set_feature(vfs_t *vfsp, vfs_feature_t feature)
4682 {
4683         /* Note that vfs_featureset[] is found in *vfsp->vfs_implp */
4684         if (vfsp->vfs_implp == NULL)
4685                 return;
4686 
4687         vfsp->vfs_featureset[VFTINDEX(feature)] |= VFTBITS(feature);
4688 }
4689 
4690 void
4691 vfs_clear_feature(vfs_t *vfsp, vfs_feature_t feature)
4692 {
4693         /* Note that vfs_featureset[] is found in *vfsp->vfs_implp */
4694         if (vfsp->vfs_implp == NULL)
4695                 return;
4696         vfsp->vfs_featureset[VFTINDEX(feature)] &= VFTBITS(~feature);
4697 }
4698 
4699 /*
4700  * Query a vfs for a feature.
4701  * Returns 1 if feature is present, 0 if not
4702  */
4703 int
4704 vfs_has_feature(vfs_t *vfsp, vfs_feature_t feature)
4705 {
4706         int     ret = 0;
4707 
4708         /* Note that vfs_featureset[] is found in *vfsp->vfs_implp */
4709         if (vfsp->vfs_implp == NULL)
4710                 return (ret);
4711 
4712         if (vfsp->vfs_featureset[VFTINDEX(feature)] & VFTBITS(feature))
4713                 ret = 1;
4714 
4715         return (ret);
4716 }
4717 
4718 /*
4719  * Propagate feature set from one vfs to another
4720  */
4721 void
4722 vfs_propagate_features(vfs_t *from, vfs_t *to)
4723 {
4724         int i;
4725 
4726         if (to->vfs_implp == NULL || from->vfs_implp == NULL)
4727                 return;
4728 
4729         for (i = 1; i <= to->vfs_featureset[0]; i++) {
4730                 to->vfs_featureset[i] = from->vfs_featureset[i];
4731         }
4732 }
4733 
4734 #define LOFINODE_PATH "/dev/lofi/%d"
4735 
4736 /*
4737  * Return the vnode for the lofi node if there's a lofi mount in place.
4738  * Returns -1 when there's no lofi node, 0 on success, and > 0 on
4739  * failure.
4740  */
4741 int
4742 vfs_get_lofi(vfs_t *vfsp, vnode_t **vpp)
4743 {
4744         char *path = NULL;
4745         int strsize;
4746         int err;
4747 
4748         if (vfsp->vfs_lofi_id == 0) {
4749                 *vpp = NULL;
4750                 return (-1);
4751         }
4752 
4753         strsize = snprintf(NULL, 0, LOFINODE_PATH, vfsp->vfs_lofi_id);
4754         path = kmem_alloc(strsize + 1, KM_SLEEP);
4755         (void) snprintf(path, strsize + 1, LOFINODE_PATH, vfsp->vfs_lofi_id);
4756 
4757         /*
4758          * We may be inside a zone, so we need to use the /dev path, but
4759          * it's created asynchronously, so we wait here.
4760          */
4761         for (;;) {
4762                 err = lookupname(path, UIO_SYSSPACE, FOLLOW, NULLVPP, vpp);
4763 
4764                 if (err != ENOENT)
4765                         break;
4766 
4767                 if ((err = delay_sig(hz / 8)) == EINTR)
4768                         break;
4769         }
4770 
4771         if (err)
4772                 *vpp = NULL;
4773 
4774         kmem_free(path, strsize + 1);
4775         return (err);
4776 }