module/os/linux/zfs/zfs_vfsops.c

   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 https://opensource.org/licenses/CDDL-1.0.
  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  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
  24  */
  25
  26 /* Portions Copyright 2010 Robert Milkowski */
  27
  28 #include <sys/types.h>
  29 #include <sys/param.h>
  30 #include <sys/sysmacros.h>
  31 #include <sys/kmem.h>
  32 #include <sys/pathname.h>
  33 #include <sys/vnode.h>
  34 #include <sys/vfs.h>
  35 #include <sys/mntent.h>
  36 #include <sys/cmn_err.h>
  37 #include <sys/zfs_znode.h>
  38 #include <sys/zfs_vnops.h>
  39 #include <sys/zfs_dir.h>
  40 #include <sys/zil.h>
  41 #include <sys/fs/zfs.h>
  42 #include <sys/dmu.h>
  43 #include <sys/dsl_prop.h>
  44 #include <sys/dsl_dataset.h>
  45 #include <sys/dsl_deleg.h>
  46 #include <sys/spa.h>
  47 #include <sys/zap.h>
  48 #include <sys/sa.h>
  49 #include <sys/sa_impl.h>
  50 #include <sys/policy.h>
  51 #include <sys/atomic.h>
  52 #include <sys/zfs_ioctl.h>
  53 #include <sys/zfs_ctldir.h>
  54 #include <sys/zfs_fuid.h>
  55 #include <sys/zfs_quota.h>
  56 #include <sys/sunddi.h>
  57 #include <sys/dmu_objset.h>
  58 #include <sys/dsl_dir.h>
  59 #include <sys/objlist.h>
  60 #include <sys/zpl.h>
  61 #include <linux/vfs_compat.h>
  62 #include "zfs_comutil.h"
  63
  64 enum {
  65         TOKEN_RO,
  66         TOKEN_RW,
  67         TOKEN_SETUID,
  68         TOKEN_NOSETUID,
  69         TOKEN_EXEC,
  70         TOKEN_NOEXEC,
  71         TOKEN_DEVICES,
  72         TOKEN_NODEVICES,
  73         TOKEN_DIRXATTR,
  74         TOKEN_SAXATTR,
  75         TOKEN_XATTR,
  76         TOKEN_NOXATTR,
  77         TOKEN_ATIME,
  78         TOKEN_NOATIME,
  79         TOKEN_RELATIME,
  80         TOKEN_NORELATIME,
  81         TOKEN_NBMAND,
  82         TOKEN_NONBMAND,
  83         TOKEN_MNTPOINT,
  84         TOKEN_LAST,
  85 };
  86
  87 static const match_table_t zpl_tokens = {
  88         { TOKEN_RO,             MNTOPT_RO },
  89         { TOKEN_RW,             MNTOPT_RW },
  90         { TOKEN_SETUID,         MNTOPT_SETUID },
  91         { TOKEN_NOSETUID,       MNTOPT_NOSETUID },
  92         { TOKEN_EXEC,           MNTOPT_EXEC },
  93         { TOKEN_NOEXEC,         MNTOPT_NOEXEC },
  94         { TOKEN_DEVICES,        MNTOPT_DEVICES },
  95         { TOKEN_NODEVICES,      MNTOPT_NODEVICES },
  96         { TOKEN_DIRXATTR,       MNTOPT_DIRXATTR },
  97         { TOKEN_SAXATTR,        MNTOPT_SAXATTR },
  98         { TOKEN_XATTR,          MNTOPT_XATTR },
  99         { TOKEN_NOXATTR,        MNTOPT_NOXATTR },
 100         { TOKEN_ATIME,          MNTOPT_ATIME },
 101         { TOKEN_NOATIME,        MNTOPT_NOATIME },
 102         { TOKEN_RELATIME,       MNTOPT_RELATIME },
 103         { TOKEN_NORELATIME,     MNTOPT_NORELATIME },
 104         { TOKEN_NBMAND,         MNTOPT_NBMAND },
 105         { TOKEN_NONBMAND,       MNTOPT_NONBMAND },
 106         { TOKEN_MNTPOINT,       MNTOPT_MNTPOINT "=%s" },
 107         { TOKEN_LAST,           NULL },
 108 };
 109
 110 static void
 111 zfsvfs_vfs_free(vfs_t *vfsp)
 112 {
 113         if (vfsp != NULL) {
 114                 if (vfsp->vfs_mntpoint != NULL)
 115                         kmem_strfree(vfsp->vfs_mntpoint);
 116
 117                 kmem_free(vfsp, sizeof (vfs_t));
 118         }
 119 }
 120
 121 static int
 122 zfsvfs_parse_option(char *option, int token, substring_t *args, vfs_t *vfsp)
 123 {
 124         switch (token) {
 125         case TOKEN_RO:
 126                 vfsp->vfs_readonly = B_TRUE;
 127                 vfsp->vfs_do_readonly = B_TRUE;
 128                 break;
 129         case TOKEN_RW:
 130                 vfsp->vfs_readonly = B_FALSE;
 131                 vfsp->vfs_do_readonly = B_TRUE;
 132                 break;
 133         case TOKEN_SETUID:
 134                 vfsp->vfs_setuid = B_TRUE;
 135                 vfsp->vfs_do_setuid = B_TRUE;
 136                 break;
 137         case TOKEN_NOSETUID:
 138                 vfsp->vfs_setuid = B_FALSE;
 139                 vfsp->vfs_do_setuid = B_TRUE;
 140                 break;
 141         case TOKEN_EXEC:
 142                 vfsp->vfs_exec = B_TRUE;
 143                 vfsp->vfs_do_exec = B_TRUE;
 144                 break;
 145         case TOKEN_NOEXEC:
 146                 vfsp->vfs_exec = B_FALSE;
 147                 vfsp->vfs_do_exec = B_TRUE;
 148                 break;
 149         case TOKEN_DEVICES:
 150                 vfsp->vfs_devices = B_TRUE;
 151                 vfsp->vfs_do_devices = B_TRUE;
 152                 break;
 153         case TOKEN_NODEVICES:
 154                 vfsp->vfs_devices = B_FALSE;
 155                 vfsp->vfs_do_devices = B_TRUE;
 156                 break;
 157         case TOKEN_DIRXATTR:
 158                 vfsp->vfs_xattr = ZFS_XATTR_DIR;
 159                 vfsp->vfs_do_xattr = B_TRUE;
 160                 break;
 161         case TOKEN_SAXATTR:
 162                 vfsp->vfs_xattr = ZFS_XATTR_SA;
 163                 vfsp->vfs_do_xattr = B_TRUE;
 164                 break;
 165         case TOKEN_XATTR:
 166                 vfsp->vfs_xattr = ZFS_XATTR_DIR;
 167                 vfsp->vfs_do_xattr = B_TRUE;
 168                 break;
 169         case TOKEN_NOXATTR:
 170                 vfsp->vfs_xattr = ZFS_XATTR_OFF;
 171                 vfsp->vfs_do_xattr = B_TRUE;
 172                 break;
 173         case TOKEN_ATIME:
 174                 vfsp->vfs_atime = B_TRUE;
 175                 vfsp->vfs_do_atime = B_TRUE;
 176                 break;
 177         case TOKEN_NOATIME:
 178                 vfsp->vfs_atime = B_FALSE;
 179                 vfsp->vfs_do_atime = B_TRUE;
 180                 break;
 181         case TOKEN_RELATIME:
 182                 vfsp->vfs_relatime = B_TRUE;
 183                 vfsp->vfs_do_relatime = B_TRUE;
 184                 break;
 185         case TOKEN_NORELATIME:
 186                 vfsp->vfs_relatime = B_FALSE;
 187                 vfsp->vfs_do_relatime = B_TRUE;
 188                 break;
 189         case TOKEN_NBMAND:
 190                 vfsp->vfs_nbmand = B_TRUE;
 191                 vfsp->vfs_do_nbmand = B_TRUE;
 192                 break;
 193         case TOKEN_NONBMAND:
 194                 vfsp->vfs_nbmand = B_FALSE;
 195                 vfsp->vfs_do_nbmand = B_TRUE;
 196                 break;
 197         case TOKEN_MNTPOINT:
 198                 vfsp->vfs_mntpoint = match_strdup(&args[0]);
 199                 if (vfsp->vfs_mntpoint == NULL)
 200                         return (SET_ERROR(ENOMEM));
 201
 202                 break;
 203         default:
 204                 break;
 205         }
 206
 207         return (0);
 208 }
 209
 210 /*
 211  * Parse the raw mntopts and return a vfs_t describing the options.
 212  */
 213 static int
 214 zfsvfs_parse_options(char *mntopts, vfs_t **vfsp)
 215 {
 216         vfs_t *tmp_vfsp;
 217         int error;
 218
 219         tmp_vfsp = kmem_zalloc(sizeof (vfs_t), KM_SLEEP);
 220
 221         if (mntopts != NULL) {
 222                 substring_t args[MAX_OPT_ARGS];
 223                 char *tmp_mntopts, *p, *t;
 224                 int token;
 225
 226                 tmp_mntopts = t = kmem_strdup(mntopts);
 227                 if (tmp_mntopts == NULL)
 228                         return (SET_ERROR(ENOMEM));
 229
 230                 while ((p = strsep(&t, ",")) != NULL) {
 231                         if (!*p)
 232                                 continue;
 233
 234                         args[0].to = args[0].from = NULL;
 235                         token = match_token(p, zpl_tokens, args);
 236                         error = zfsvfs_parse_option(p, token, args, tmp_vfsp);
 237                         if (error) {
 238                                 kmem_strfree(tmp_mntopts);
 239                                 zfsvfs_vfs_free(tmp_vfsp);
 240                                 return (error);
 241                         }
 242                 }
 243
 244                 kmem_strfree(tmp_mntopts);
 245         }
 246
 247         *vfsp = tmp_vfsp;
 248
 249         return (0);
 250 }
 251
 252 boolean_t
 253 zfs_is_readonly(zfsvfs_t *zfsvfs)
 254 {
 255         return (!!(zfsvfs->z_sb->s_flags & SB_RDONLY));
 256 }
 257
 258 int
 259 zfs_sync(struct super_block *sb, int wait, cred_t *cr)
 260 {
 261         (void) cr;
 262         zfsvfs_t *zfsvfs = sb->s_fs_info;
 263
 264         /*
 265          * Semantically, the only requirement is that the sync be initiated.
 266          * The DMU syncs out txgs frequently, so there's nothing to do.
 267          */
 268         if (!wait)
 269                 return (0);
 270
 271         if (zfsvfs != NULL) {
 272                 /*
 273                  * Sync a specific filesystem.
 274                  */
 275                 dsl_pool_t *dp;
 276                 int error;
 277
 278                 if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
 279                         return (error);
 280                 dp = dmu_objset_pool(zfsvfs->z_os);
 281
 282                 /*
 283                  * If the system is shutting down, then skip any
 284                  * filesystems which may exist on a suspended pool.
 285                  */
 286                 if (spa_suspended(dp->dp_spa)) {
 287                         zfs_exit(zfsvfs, FTAG);
 288                         return (0);
 289                 }
 290
 291                 if (zfsvfs->z_log != NULL)
 292                         zil_commit(zfsvfs->z_log, 0);
 293
 294                 zfs_exit(zfsvfs, FTAG);
 295         } else {
 296                 /*
 297                  * Sync all ZFS filesystems.  This is what happens when you
 298                  * run sync(1).  Unlike other filesystems, ZFS honors the
 299                  * request by waiting for all pools to commit all dirty data.
 300                  */
 301                 spa_sync_allpools();
 302         }
 303
 304         return (0);
 305 }
 306
 307 static void
 308 atime_changed_cb(void *arg, uint64_t newval)
 309 {
 310         zfsvfs_t *zfsvfs = arg;
 311         struct super_block *sb = zfsvfs->z_sb;
 312
 313         if (sb == NULL)
 314                 return;
 315         /*
 316          * Update SB_NOATIME bit in VFS super block.  Since atime update is
 317          * determined by atime_needs_update(), atime_needs_update() needs to
 318          * return false if atime is turned off, and not unconditionally return
 319          * false if atime is turned on.
 320          */
 321         if (newval)
 322                 sb->s_flags &= ~SB_NOATIME;
 323         else
 324                 sb->s_flags |= SB_NOATIME;
 325 }
 326
 327 static void
 328 relatime_changed_cb(void *arg, uint64_t newval)
 329 {
 330         ((zfsvfs_t *)arg)->z_relatime = newval;
 331 }
 332
 333 static void
 334 xattr_changed_cb(void *arg, uint64_t newval)
 335 {
 336         zfsvfs_t *zfsvfs = arg;
 337
 338         if (newval == ZFS_XATTR_OFF) {
 339                 zfsvfs->z_flags &= ~ZSB_XATTR;
 340         } else {
 341                 zfsvfs->z_flags |= ZSB_XATTR;
 342
 343                 if (newval == ZFS_XATTR_SA)
 344                         zfsvfs->z_xattr_sa = B_TRUE;
 345                 else
 346                         zfsvfs->z_xattr_sa = B_FALSE;
 347         }
 348 }
 349
 350 static void
 351 acltype_changed_cb(void *arg, uint64_t newval)
 352 {
 353         zfsvfs_t *zfsvfs = arg;
 354
 355         switch (newval) {
 356         case ZFS_ACLTYPE_NFSV4:
 357         case ZFS_ACLTYPE_OFF:
 358                 zfsvfs->z_acl_type = ZFS_ACLTYPE_OFF;
 359                 zfsvfs->z_sb->s_flags &= ~SB_POSIXACL;
 360                 break;
 361         case ZFS_ACLTYPE_POSIX:
 362 #ifdef CONFIG_FS_POSIX_ACL
 363                 zfsvfs->z_acl_type = ZFS_ACLTYPE_POSIX;
 364                 zfsvfs->z_sb->s_flags |= SB_POSIXACL;
 365 #else
 366                 zfsvfs->z_acl_type = ZFS_ACLTYPE_OFF;
 367                 zfsvfs->z_sb->s_flags &= ~SB_POSIXACL;
 368 #endif /* CONFIG_FS_POSIX_ACL */
 369                 break;
 370         default:
 371                 break;
 372         }
 373 }
 374
 375 static void
 376 blksz_changed_cb(void *arg, uint64_t newval)
 377 {
 378         zfsvfs_t *zfsvfs = arg;
 379         ASSERT3U(newval, <=, spa_maxblocksize(dmu_objset_spa(zfsvfs->z_os)));
 380         ASSERT3U(newval, >=, SPA_MINBLOCKSIZE);
 381         ASSERT(ISP2(newval));
 382
 383         zfsvfs->z_max_blksz = newval;
 384 }
 385
 386 static void
 387 readonly_changed_cb(void *arg, uint64_t newval)
 388 {
 389         zfsvfs_t *zfsvfs = arg;
 390         struct super_block *sb = zfsvfs->z_sb;
 391
 392         if (sb == NULL)
 393                 return;
 394
 395         if (newval)
 396                 sb->s_flags |= SB_RDONLY;
 397         else
 398                 sb->s_flags &= ~SB_RDONLY;
 399 }
 400
 401 static void
 402 devices_changed_cb(void *arg, uint64_t newval)
 403 {
 404 }
 405
 406 static void
 407 setuid_changed_cb(void *arg, uint64_t newval)
 408 {
 409 }
 410
 411 static void
 412 exec_changed_cb(void *arg, uint64_t newval)
 413 {
 414 }
 415
 416 static void
 417 nbmand_changed_cb(void *arg, uint64_t newval)
 418 {
 419         zfsvfs_t *zfsvfs = arg;
 420         struct super_block *sb = zfsvfs->z_sb;
 421
 422         if (sb == NULL)
 423                 return;
 424
 425         if (newval == TRUE)
 426                 sb->s_flags |= SB_MANDLOCK;
 427         else
 428                 sb->s_flags &= ~SB_MANDLOCK;
 429 }
 430
 431 static void
 432 snapdir_changed_cb(void *arg, uint64_t newval)
 433 {
 434         ((zfsvfs_t *)arg)->z_show_ctldir = newval;
 435 }
 436
 437 static void
 438 acl_mode_changed_cb(void *arg, uint64_t newval)
 439 {
 440         zfsvfs_t *zfsvfs = arg;
 441
 442         zfsvfs->z_acl_mode = newval;
 443 }
 444
 445 static void
 446 acl_inherit_changed_cb(void *arg, uint64_t newval)
 447 {
 448         ((zfsvfs_t *)arg)->z_acl_inherit = newval;
 449 }
 450
 451 static int
 452 zfs_register_callbacks(vfs_t *vfsp)
 453 {
 454         struct dsl_dataset *ds = NULL;
 455         objset_t *os = NULL;
 456         zfsvfs_t *zfsvfs = NULL;
 457         int error = 0;
 458
 459         ASSERT(vfsp);
 460         zfsvfs = vfsp->vfs_data;
 461         ASSERT(zfsvfs);
 462         os = zfsvfs->z_os;
 463
 464         /*
 465          * The act of registering our callbacks will destroy any mount
 466          * options we may have.  In order to enable temporary overrides
 467          * of mount options, we stash away the current values and
 468          * restore them after we register the callbacks.
 469          */
 470         if (zfs_is_readonly(zfsvfs) || !spa_writeable(dmu_objset_spa(os))) {
 471                 vfsp->vfs_do_readonly = B_TRUE;
 472                 vfsp->vfs_readonly = B_TRUE;
 473         }
 474
 475         /*
 476          * Register property callbacks.
 477          *
 478          * It would probably be fine to just check for i/o error from
 479          * the first prop_register(), but I guess I like to go
 480          * overboard...
 481          */
 482         ds = dmu_objset_ds(os);
 483         dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
 484         error = dsl_prop_register(ds,
 485             zfs_prop_to_name(ZFS_PROP_ATIME), atime_changed_cb, zfsvfs);
 486         error = error ? error : dsl_prop_register(ds,
 487             zfs_prop_to_name(ZFS_PROP_RELATIME), relatime_changed_cb, zfsvfs);
 488         error = error ? error : dsl_prop_register(ds,
 489             zfs_prop_to_name(ZFS_PROP_XATTR), xattr_changed_cb, zfsvfs);
 490         error = error ? error : dsl_prop_register(ds,
 491             zfs_prop_to_name(ZFS_PROP_RECORDSIZE), blksz_changed_cb, zfsvfs);
 492         error = error ? error : dsl_prop_register(ds,
 493             zfs_prop_to_name(ZFS_PROP_READONLY), readonly_changed_cb, zfsvfs);
 494         error = error ? error : dsl_prop_register(ds,
 495             zfs_prop_to_name(ZFS_PROP_DEVICES), devices_changed_cb, zfsvfs);
 496         error = error ? error : dsl_prop_register(ds,
 497             zfs_prop_to_name(ZFS_PROP_SETUID), setuid_changed_cb, zfsvfs);
 498         error = error ? error : dsl_prop_register(ds,
 499             zfs_prop_to_name(ZFS_PROP_EXEC), exec_changed_cb, zfsvfs);
 500         error = error ? error : dsl_prop_register(ds,
 501             zfs_prop_to_name(ZFS_PROP_SNAPDIR), snapdir_changed_cb, zfsvfs);
 502         error = error ? error : dsl_prop_register(ds,
 503             zfs_prop_to_name(ZFS_PROP_ACLTYPE), acltype_changed_cb, zfsvfs);
 504         error = error ? error : dsl_prop_register(ds,
 505             zfs_prop_to_name(ZFS_PROP_ACLMODE), acl_mode_changed_cb, zfsvfs);
 506         error = error ? error : dsl_prop_register(ds,
 507             zfs_prop_to_name(ZFS_PROP_ACLINHERIT), acl_inherit_changed_cb,
 508             zfsvfs);
 509         error = error ? error : dsl_prop_register(ds,
 510             zfs_prop_to_name(ZFS_PROP_NBMAND), nbmand_changed_cb, zfsvfs);
 511         dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
 512         if (error)
 513                 goto unregister;
 514
 515         /*
 516          * Invoke our callbacks to restore temporary mount options.
 517          */
 518         if (vfsp->vfs_do_readonly)
 519                 readonly_changed_cb(zfsvfs, vfsp->vfs_readonly);
 520         if (vfsp->vfs_do_setuid)
 521                 setuid_changed_cb(zfsvfs, vfsp->vfs_setuid);
 522         if (vfsp->vfs_do_exec)
 523                 exec_changed_cb(zfsvfs, vfsp->vfs_exec);
 524         if (vfsp->vfs_do_devices)
 525                 devices_changed_cb(zfsvfs, vfsp->vfs_devices);
 526         if (vfsp->vfs_do_xattr)
 527                 xattr_changed_cb(zfsvfs, vfsp->vfs_xattr);
 528         if (vfsp->vfs_do_atime)
 529                 atime_changed_cb(zfsvfs, vfsp->vfs_atime);
 530         if (vfsp->vfs_do_relatime)
 531                 relatime_changed_cb(zfsvfs, vfsp->vfs_relatime);
 532         if (vfsp->vfs_do_nbmand)
 533                 nbmand_changed_cb(zfsvfs, vfsp->vfs_nbmand);
 534
 535         return (0);
 536
 537 unregister:
 538         dsl_prop_unregister_all(ds, zfsvfs);
 539         return (error);
 540 }
 541
 542 /*
 543  * Takes a dataset, a property, a value and that value's setpoint as
 544  * found in the ZAP. Checks if the property has been changed in the vfs.
 545  * If so, val and setpoint will be overwritten with updated content.
 546  * Otherwise, they are left unchanged.
 547  */
 548 int
 549 zfs_get_temporary_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop, uint64_t *val,
 550     char *setpoint)
 551 {
 552         int error;
 553         zfsvfs_t *zfvp;
 554         vfs_t *vfsp;
 555         objset_t *os;
 556         uint64_t tmp = *val;
 557
 558         error = dmu_objset_from_ds(ds, &os);
 559         if (error != 0)
 560                 return (error);
 561
 562         if (dmu_objset_type(os) != DMU_OST_ZFS)
 563                 return (EINVAL);
 564
 565         mutex_enter(&os->os_user_ptr_lock);
 566         zfvp = dmu_objset_get_user(os);
 567         mutex_exit(&os->os_user_ptr_lock);
 568         if (zfvp == NULL)
 569                 return (ESRCH);
 570
 571         vfsp = zfvp->z_vfs;
 572
 573         switch (zfs_prop) {
 574         case ZFS_PROP_ATIME:
 575                 if (vfsp->vfs_do_atime)
 576                         tmp = vfsp->vfs_atime;
 577                 break;
 578         case ZFS_PROP_RELATIME:
 579                 if (vfsp->vfs_do_relatime)
 580                         tmp = vfsp->vfs_relatime;
 581                 break;
 582         case ZFS_PROP_DEVICES:
 583                 if (vfsp->vfs_do_devices)
 584                         tmp = vfsp->vfs_devices;
 585                 break;
 586         case ZFS_PROP_EXEC:
 587                 if (vfsp->vfs_do_exec)
 588                         tmp = vfsp->vfs_exec;
 589                 break;
 590         case ZFS_PROP_SETUID:
 591                 if (vfsp->vfs_do_setuid)
 592                         tmp = vfsp->vfs_setuid;
 593                 break;
 594         case ZFS_PROP_READONLY:
 595                 if (vfsp->vfs_do_readonly)
 596                         tmp = vfsp->vfs_readonly;
 597                 break;
 598         case ZFS_PROP_XATTR:
 599                 if (vfsp->vfs_do_xattr)
 600                         tmp = vfsp->vfs_xattr;
 601                 break;
 602         case ZFS_PROP_NBMAND:
 603                 if (vfsp->vfs_do_nbmand)
 604                         tmp = vfsp->vfs_nbmand;
 605                 break;
 606         default:
 607                 return (ENOENT);
 608         }
 609
 610         if (tmp != *val) {
 611                 if (setpoint)
 612                         (void) strcpy(setpoint, "temporary");
 613                 *val = tmp;
 614         }
 615         return (0);
 616 }
 617
 618 /*
 619  * Associate this zfsvfs with the given objset, which must be owned.
 620  * This will cache a bunch of on-disk state from the objset in the
 621  * zfsvfs.
 622  */
 623 static int
 624 zfsvfs_init(zfsvfs_t *zfsvfs, objset_t *os)
 625 {
 626         int error;
 627         uint64_t val;
 628
 629         zfsvfs->z_max_blksz = SPA_OLD_MAXBLOCKSIZE;
 630         zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
 631         zfsvfs->z_os = os;
 632
 633         error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
 634         if (error != 0)
 635                 return (error);
 636         if (zfsvfs->z_version >
 637             zfs_zpl_version_map(spa_version(dmu_objset_spa(os)))) {
 638                 (void) printk("Can't mount a version %lld file system "
 639                     "on a version %lld pool\n. Pool must be upgraded to mount "
 640                     "this file system.\n", (u_longlong_t)zfsvfs->z_version,
 641                     (u_longlong_t)spa_version(dmu_objset_spa(os)));
 642                 return (SET_ERROR(ENOTSUP));
 643         }
 644         error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &val);
 645         if (error != 0)
 646                 return (error);
 647         zfsvfs->z_norm = (int)val;
 648
 649         error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &val);
 650         if (error != 0)
 651                 return (error);
 652         zfsvfs->z_utf8 = (val != 0);
 653
 654         error = zfs_get_zplprop(os, ZFS_PROP_CASE, &val);
 655         if (error != 0)
 656                 return (error);
 657         zfsvfs->z_case = (uint_t)val;
 658
 659         if ((error = zfs_get_zplprop(os, ZFS_PROP_ACLTYPE, &val)) != 0)
 660                 return (error);
 661         zfsvfs->z_acl_type = (uint_t)val;
 662
 663         /*
 664          * Fold case on file systems that are always or sometimes case
 665          * insensitive.
 666          */
 667         if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
 668             zfsvfs->z_case == ZFS_CASE_MIXED)
 669                 zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;
 670
 671         zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
 672         zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
 673
 674         uint64_t sa_obj = 0;
 675         if (zfsvfs->z_use_sa) {
 676                 /* should either have both of these objects or none */
 677                 error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SA_ATTRS, 8, 1,
 678                     &sa_obj);
 679                 if (error != 0)
 680                         return (error);
 681
 682                 error = zfs_get_zplprop(os, ZFS_PROP_XATTR, &val);
 683                 if ((error == 0) && (val == ZFS_XATTR_SA))
 684                         zfsvfs->z_xattr_sa = B_TRUE;
 685         }
 686
 687         error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
 688             &zfsvfs->z_root);
 689         if (error != 0)
 690                 return (error);
 691         ASSERT(zfsvfs->z_root != 0);
 692
 693         error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
 694             &zfsvfs->z_unlinkedobj);
 695         if (error != 0)
 696                 return (error);
 697
 698         error = zap_lookup(os, MASTER_NODE_OBJ,
 699             zfs_userquota_prop_prefixes[ZFS_PROP_USERQUOTA],
 700             8, 1, &zfsvfs->z_userquota_obj);
 701         if (error == ENOENT)
 702                 zfsvfs->z_userquota_obj = 0;
 703         else if (error != 0)
 704                 return (error);
 705
 706         error = zap_lookup(os, MASTER_NODE_OBJ,
 707             zfs_userquota_prop_prefixes[ZFS_PROP_GROUPQUOTA],
 708             8, 1, &zfsvfs->z_groupquota_obj);
 709         if (error == ENOENT)
 710                 zfsvfs->z_groupquota_obj = 0;
 711         else if (error != 0)
 712                 return (error);
 713
 714         error = zap_lookup(os, MASTER_NODE_OBJ,
 715             zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTQUOTA],
 716             8, 1, &zfsvfs->z_projectquota_obj);
 717         if (error == ENOENT)
 718                 zfsvfs->z_projectquota_obj = 0;
 719         else if (error != 0)
 720                 return (error);
 721
 722         error = zap_lookup(os, MASTER_NODE_OBJ,
 723             zfs_userquota_prop_prefixes[ZFS_PROP_USEROBJQUOTA],
 724             8, 1, &zfsvfs->z_userobjquota_obj);
 725         if (error == ENOENT)
 726                 zfsvfs->z_userobjquota_obj = 0;
 727         else if (error != 0)
 728                 return (error);
 729
 730         error = zap_lookup(os, MASTER_NODE_OBJ,
 731             zfs_userquota_prop_prefixes[ZFS_PROP_GROUPOBJQUOTA],
 732             8, 1, &zfsvfs->z_groupobjquota_obj);
 733         if (error == ENOENT)
 734                 zfsvfs->z_groupobjquota_obj = 0;
 735         else if (error != 0)
 736                 return (error);
 737
 738         error = zap_lookup(os, MASTER_NODE_OBJ,
 739             zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTOBJQUOTA],
 740             8, 1, &zfsvfs->z_projectobjquota_obj);
 741         if (error == ENOENT)
 742                 zfsvfs->z_projectobjquota_obj = 0;
 743         else if (error != 0)
 744                 return (error);
 745
 746         error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
 747             &zfsvfs->z_fuid_obj);
 748         if (error == ENOENT)
 749                 zfsvfs->z_fuid_obj = 0;
 750         else if (error != 0)
 751                 return (error);
 752
 753         error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SHARES_DIR, 8, 1,
 754             &zfsvfs->z_shares_dir);
 755         if (error == ENOENT)
 756                 zfsvfs->z_shares_dir = 0;
 757         else if (error != 0)
 758                 return (error);
 759
 760         error = sa_setup(os, sa_obj, zfs_attr_table, ZPL_END,
 761             &zfsvfs->z_attr_table);
 762         if (error != 0)
 763                 return (error);
 764
 765         if (zfsvfs->z_version >= ZPL_VERSION_SA)
 766                 sa_register_update_callback(os, zfs_sa_upgrade);
 767
 768         return (0);
 769 }
 770
 771 int
 772 zfsvfs_create(const char *osname, boolean_t readonly, zfsvfs_t **zfvp)
 773 {
 774         objset_t *os;
 775         zfsvfs_t *zfsvfs;
 776         int error;
 777         boolean_t ro = (readonly || (strchr(osname, '@') != NULL));
 778
 779         zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
 780
 781         error = dmu_objset_own(osname, DMU_OST_ZFS, ro, B_TRUE, zfsvfs, &os);
 782         if (error != 0) {
 783                 kmem_free(zfsvfs, sizeof (zfsvfs_t));
 784                 return (error);
 785         }
 786
 787         error = zfsvfs_create_impl(zfvp, zfsvfs, os);
 788
 789         return (error);
 790 }
 791
 792
 793 /*
 794  * Note: zfsvfs is assumed to be malloc'd, and will be freed by this function
 795  * on a failure.  Do not pass in a statically allocated zfsvfs.
 796  */
 797 int
 798 zfsvfs_create_impl(zfsvfs_t **zfvp, zfsvfs_t *zfsvfs, objset_t *os)
 799 {
 800         int error;
 801
 802         zfsvfs->z_vfs = NULL;
 803         zfsvfs->z_sb = NULL;
 804         zfsvfs->z_parent = zfsvfs;
 805
 806         mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
 807         mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
 808         list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
 809             offsetof(znode_t, z_link_node));
 810         ZFS_TEARDOWN_INIT(zfsvfs);
 811         rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
 812         rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
 813
 814         int size = MIN(1 << (highbit64(zfs_object_mutex_size) - 1),
 815             ZFS_OBJ_MTX_MAX);
 816         zfsvfs->z_hold_size = size;
 817         zfsvfs->z_hold_trees = vmem_zalloc(sizeof (avl_tree_t) * size,
 818             KM_SLEEP);
 819         zfsvfs->z_hold_locks = vmem_zalloc(sizeof (kmutex_t) * size, KM_SLEEP);
 820         for (int i = 0; i != size; i++) {
 821                 avl_create(&zfsvfs->z_hold_trees[i], zfs_znode_hold_compare,
 822                     sizeof (znode_hold_t), offsetof(znode_hold_t, zh_node));
 823                 mutex_init(&zfsvfs->z_hold_locks[i], NULL, MUTEX_DEFAULT, NULL);
 824         }
 825
 826         error = zfsvfs_init(zfsvfs, os);
 827         if (error != 0) {
 828                 dmu_objset_disown(os, B_TRUE, zfsvfs);
 829                 *zfvp = NULL;
 830                 zfsvfs_free(zfsvfs);
 831                 return (error);
 832         }
 833
 834         zfsvfs->z_drain_task = TASKQID_INVALID;
 835         zfsvfs->z_draining = B_FALSE;
 836         zfsvfs->z_drain_cancel = B_TRUE;
 837
 838         *zfvp = zfsvfs;
 839         return (0);
 840 }
 841
 842 static int
 843 zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
 844 {
 845         int error;
 846         boolean_t readonly = zfs_is_readonly(zfsvfs);
 847
 848         error = zfs_register_callbacks(zfsvfs->z_vfs);
 849         if (error)
 850                 return (error);
 851
 852         /*
 853          * If we are not mounting (ie: online recv), then we don't
 854          * have to worry about replaying the log as we blocked all
 855          * operations out since we closed the ZIL.
 856          */
 857         if (mounting) {
 858                 ASSERT3P(zfsvfs->z_kstat.dk_kstats, ==, NULL);
 859                 error = dataset_kstats_create(&zfsvfs->z_kstat, zfsvfs->z_os);
 860                 if (error)
 861                         return (error);
 862                 zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
 863                     &zfsvfs->z_kstat.dk_zil_sums);
 864
 865                 /*
 866                  * During replay we remove the read only flag to
 867                  * allow replays to succeed.
 868                  */
 869                 if (readonly != 0) {
 870                         readonly_changed_cb(zfsvfs, B_FALSE);
 871                 } else {
 872                         zap_stats_t zs;
 873                         if (zap_get_stats(zfsvfs->z_os, zfsvfs->z_unlinkedobj,
 874                             &zs) == 0) {
 875                                 dataset_kstats_update_nunlinks_kstat(
 876                                     &zfsvfs->z_kstat, zs.zs_num_entries);
 877                                 dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
 878                                     "num_entries in unlinked set: %llu",
 879                                     zs.zs_num_entries);
 880                         }
 881                         zfs_unlinked_drain(zfsvfs);
 882                         dsl_dir_t *dd = zfsvfs->z_os->os_dsl_dataset->ds_dir;
 883                         dd->dd_activity_cancelled = B_FALSE;
 884                 }
 885
 886                 /*
 887                  * Parse and replay the intent log.
 888                  *
 889                  * Because of ziltest, this must be done after
 890                  * zfs_unlinked_drain().  (Further note: ziltest
 891                  * doesn't use readonly mounts, where
 892                  * zfs_unlinked_drain() isn't called.)  This is because
 893                  * ziltest causes spa_sync() to think it's committed,
 894                  * but actually it is not, so the intent log contains
 895                  * many txg's worth of changes.
 896                  *
 897                  * In particular, if object N is in the unlinked set in
 898                  * the last txg to actually sync, then it could be
 899                  * actually freed in a later txg and then reallocated
 900                  * in a yet later txg.  This would write a "create
 901                  * object N" record to the intent log.  Normally, this
 902                  * would be fine because the spa_sync() would have
 903                  * written out the fact that object N is free, before
 904                  * we could write the "create object N" intent log
 905                  * record.
 906                  *
 907                  * But when we are in ziltest mode, we advance the "open
 908                  * txg" without actually spa_sync()-ing the changes to
 909                  * disk.  So we would see that object N is still
 910                  * allocated and in the unlinked set, and there is an
 911                  * intent log record saying to allocate it.
 912                  */
 913                 if (spa_writeable(dmu_objset_spa(zfsvfs->z_os))) {
 914                         if (zil_replay_disable) {
 915                                 zil_destroy(zfsvfs->z_log, B_FALSE);
 916                         } else {
 917                                 zfsvfs->z_replay = B_TRUE;
 918                                 zil_replay(zfsvfs->z_os, zfsvfs,
 919                                     zfs_replay_vector);
 920                                 zfsvfs->z_replay = B_FALSE;
 921                         }
 922                 }
 923
 924                 /* restore readonly bit */
 925                 if (readonly != 0)
 926                         readonly_changed_cb(zfsvfs, B_TRUE);
 927         } else {
 928                 ASSERT3P(zfsvfs->z_kstat.dk_kstats, !=, NULL);
 929                 zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
 930                     &zfsvfs->z_kstat.dk_zil_sums);
 931         }
 932
 933         /*
 934          * Set the objset user_ptr to track its zfsvfs.
 935          */
 936         mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
 937         dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
 938         mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
 939
 940         return (0);
 941 }
 942
 943 void
 944 zfsvfs_free(zfsvfs_t *zfsvfs)
 945 {
 946         int i, size = zfsvfs->z_hold_size;
 947
 948         zfs_fuid_destroy(zfsvfs);
 949
 950         mutex_destroy(&zfsvfs->z_znodes_lock);
 951         mutex_destroy(&zfsvfs->z_lock);
 952         list_destroy(&zfsvfs->z_all_znodes);
 953         ZFS_TEARDOWN_DESTROY(zfsvfs);
 954         rw_destroy(&zfsvfs->z_teardown_inactive_lock);
 955         rw_destroy(&zfsvfs->z_fuid_lock);
 956         for (i = 0; i != size; i++) {
 957                 avl_destroy(&zfsvfs->z_hold_trees[i]);
 958                 mutex_destroy(&zfsvfs->z_hold_locks[i]);
 959         }
 960         vmem_free(zfsvfs->z_hold_trees, sizeof (avl_tree_t) * size);
 961         vmem_free(zfsvfs->z_hold_locks, sizeof (kmutex_t) * size);
 962         zfsvfs_vfs_free(zfsvfs->z_vfs);
 963         dataset_kstats_destroy(&zfsvfs->z_kstat);
 964         kmem_free(zfsvfs, sizeof (zfsvfs_t));
 965 }
 966
 967 static void
 968 zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
 969 {
 970         zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
 971         zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
 972 }
 973
 974 static void
 975 zfs_unregister_callbacks(zfsvfs_t *zfsvfs)
 976 {
 977         objset_t *os = zfsvfs->z_os;
 978
 979         if (!dmu_objset_is_snapshot(os))
 980                 dsl_prop_unregister_all(dmu_objset_ds(os), zfsvfs);
 981 }
 982
 983 #ifdef HAVE_MLSLABEL
 984 /*
 985  * Check that the hex label string is appropriate for the dataset being
 986  * mounted into the global_zone proper.
 987  *
 988  * Return an error if the hex label string is not default or
 989  * admin_low/admin_high.  For admin_low labels, the corresponding
 990  * dataset must be readonly.
 991  */
 992 int
 993 zfs_check_global_label(const char *dsname, const char *hexsl)
 994 {
 995         if (strcasecmp(hexsl, ZFS_MLSLABEL_DEFAULT) == 0)
 996                 return (0);
 997         if (strcasecmp(hexsl, ADMIN_HIGH) == 0)
 998                 return (0);
 999         if (strcasecmp(hexsl, ADMIN_LOW) == 0) {
1000                 /* must be readonly */
1001                 uint64_t rdonly;
1002
1003                 if (dsl_prop_get_integer(dsname,
1004                     zfs_prop_to_name(ZFS_PROP_READONLY), &rdonly, NULL))
1005                         return (SET_ERROR(EACCES));
1006                 return (rdonly ? 0 : SET_ERROR(EACCES));
1007         }
1008         return (SET_ERROR(EACCES));
1009 }
1010 #endif /* HAVE_MLSLABEL */
1011
1012 static int
1013 zfs_statfs_project(zfsvfs_t *zfsvfs, znode_t *zp, struct kstatfs *statp,
1014     uint32_t bshift)
1015 {
1016         char buf[20 + DMU_OBJACCT_PREFIX_LEN];
1017         uint64_t offset = DMU_OBJACCT_PREFIX_LEN;
1018         uint64_t quota;
1019         uint64_t used;
1020         int err;
1021
1022         strlcpy(buf, DMU_OBJACCT_PREFIX, DMU_OBJACCT_PREFIX_LEN + 1);
1023         err = zfs_id_to_fuidstr(zfsvfs, NULL, zp->z_projid, buf + offset,
1024             sizeof (buf) - offset, B_FALSE);
1025         if (err)
1026                 return (err);
1027
1028         if (zfsvfs->z_projectquota_obj == 0)
1029                 goto objs;
1030
1031         err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectquota_obj,
1032             buf + offset, 8, 1, &quota);
1033         if (err == ENOENT)
1034                 goto objs;
1035         else if (err)
1036                 return (err);
1037
1038         err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1039             buf + offset, 8, 1, &used);
1040         if (unlikely(err == ENOENT)) {
1041                 uint32_t blksize;
1042                 u_longlong_t nblocks;
1043
1044                 /*
1045                  * Quota accounting is async, so it is possible race case.
1046                  * There is at least one object with the given project ID.
1047                  */
1048                 sa_object_size(zp->z_sa_hdl, &blksize, &nblocks);
1049                 if (unlikely(zp->z_blksz == 0))
1050                         blksize = zfsvfs->z_max_blksz;
1051
1052                 used = blksize * nblocks;
1053         } else if (err) {
1054                 return (err);
1055         }
1056
1057         statp->f_blocks = quota >> bshift;
1058         statp->f_bfree = (quota > used) ? ((quota - used) >> bshift) : 0;
1059         statp->f_bavail = statp->f_bfree;
1060
1061 objs:
1062         if (zfsvfs->z_projectobjquota_obj == 0)
1063                 return (0);
1064
1065         err = zap_lookup(zfsvfs->z_os, zfsvfs->z_projectobjquota_obj,
1066             buf + offset, 8, 1, &quota);
1067         if (err == ENOENT)
1068                 return (0);
1069         else if (err)
1070                 return (err);
1071
1072         err = zap_lookup(zfsvfs->z_os, DMU_PROJECTUSED_OBJECT,
1073             buf, 8, 1, &used);
1074         if (unlikely(err == ENOENT)) {
1075                 /*
1076                  * Quota accounting is async, so it is possible race case.
1077                  * There is at least one object with the given project ID.
1078                  */
1079                 used = 1;
1080         } else if (err) {
1081                 return (err);
1082         }
1083
1084         statp->f_files = quota;
1085         statp->f_ffree = (quota > used) ? (quota - used) : 0;
1086
1087         return (0);
1088 }
1089
1090 int
1091 zfs_statvfs(struct inode *ip, struct kstatfs *statp)
1092 {
1093         zfsvfs_t *zfsvfs = ITOZSB(ip);
1094         uint64_t refdbytes, availbytes, usedobjs, availobjs;
1095         int err = 0;
1096
1097         if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1098                 return (err);
1099
1100         dmu_objset_space(zfsvfs->z_os,
1101             &refdbytes, &availbytes, &usedobjs, &availobjs);
1102
1103         uint64_t fsid = dmu_objset_fsid_guid(zfsvfs->z_os);
1104         /*
1105          * The underlying storage pool actually uses multiple block
1106          * size.  Under Solaris frsize (fragment size) is reported as
1107          * the smallest block size we support, and bsize (block size)
1108          * as the filesystem's maximum block size.  Unfortunately,
1109          * under Linux the fragment size and block size are often used
1110          * interchangeably.  Thus we are forced to report both of them
1111          * as the filesystem's maximum block size.
1112          */
1113         statp->f_frsize = zfsvfs->z_max_blksz;
1114         statp->f_bsize = zfsvfs->z_max_blksz;
1115         uint32_t bshift = fls(statp->f_bsize) - 1;
1116
1117         /*
1118          * The following report "total" blocks of various kinds in
1119          * the file system, but reported in terms of f_bsize - the
1120          * "preferred" size.
1121          */
1122
1123         /* Round up so we never have a filesystem using 0 blocks. */
1124         refdbytes = P2ROUNDUP(refdbytes, statp->f_bsize);
1125         statp->f_blocks = (refdbytes + availbytes) >> bshift;
1126         statp->f_bfree = availbytes >> bshift;
1127         statp->f_bavail = statp->f_bfree; /* no root reservation */
1128
1129         /*
1130          * statvfs() should really be called statufs(), because it assumes
1131          * static metadata.  ZFS doesn't preallocate files, so the best
1132          * we can do is report the max that could possibly fit in f_files,
1133          * and that minus the number actually used in f_ffree.
1134          * For f_ffree, report the smaller of the number of objects available
1135          * and the number of blocks (each object will take at least a block).
1136          */
1137         statp->f_ffree = MIN(availobjs, availbytes >> DNODE_SHIFT);
1138         statp->f_files = statp->f_ffree + usedobjs;
1139         statp->f_fsid.val[0] = (uint32_t)fsid;
1140         statp->f_fsid.val[1] = (uint32_t)(fsid >> 32);
1141         statp->f_type = ZFS_SUPER_MAGIC;
1142         statp->f_namelen = MAXNAMELEN - 1;
1143
1144         /*
1145          * We have all of 40 characters to stuff a string here.
1146          * Is there anything useful we could/should provide?
1147          */
1148         memset(statp->f_spare, 0, sizeof (statp->f_spare));
1149
1150         if (dmu_objset_projectquota_enabled(zfsvfs->z_os) &&
1151             dmu_objset_projectquota_present(zfsvfs->z_os)) {
1152                 znode_t *zp = ITOZ(ip);
1153
1154                 if (zp->z_pflags & ZFS_PROJINHERIT && zp->z_projid &&
1155                     zpl_is_valid_projid(zp->z_projid))
1156                         err = zfs_statfs_project(zfsvfs, zp, statp, bshift);
1157         }
1158
1159         zfs_exit(zfsvfs, FTAG);
1160         return (err);
1161 }
1162
1163 static int
1164 zfs_root(zfsvfs_t *zfsvfs, struct inode **ipp)
1165 {
1166         znode_t *rootzp;
1167         int error;
1168
1169         if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1170                 return (error);
1171
1172         error = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
1173         if (error == 0)
1174                 *ipp = ZTOI(rootzp);
1175
1176         zfs_exit(zfsvfs, FTAG);
1177         return (error);
1178 }
1179
1180 /*
1181  * Linux kernels older than 3.1 do not support a per-filesystem shrinker.
1182  * To accommodate this we must improvise and manually walk the list of znodes
1183  * attempting to prune dentries in order to be able to drop the inodes.
1184  *
1185  * To avoid scanning the same znodes multiple times they are always rotated
1186  * to the end of the z_all_znodes list.  New znodes are inserted at the
1187  * end of the list so we're always scanning the oldest znodes first.
1188  */
1189 static int
1190 zfs_prune_aliases(zfsvfs_t *zfsvfs, unsigned long nr_to_scan)
1191 {
1192         znode_t **zp_array, *zp;
1193         int max_array = MIN(nr_to_scan, PAGE_SIZE * 8 / sizeof (znode_t *));
1194         int objects = 0;
1195         int i = 0, j = 0;
1196
1197         zp_array = vmem_zalloc(max_array * sizeof (znode_t *), KM_SLEEP);
1198
1199         mutex_enter(&zfsvfs->z_znodes_lock);
1200         while ((zp = list_head(&zfsvfs->z_all_znodes)) != NULL) {
1201
1202                 if ((i++ > nr_to_scan) || (j >= max_array))
1203                         break;
1204
1205                 ASSERT(list_link_active(&zp->z_link_node));
1206                 list_remove(&zfsvfs->z_all_znodes, zp);
1207                 list_insert_tail(&zfsvfs->z_all_znodes, zp);
1208
1209                 /* Skip active znodes and .zfs entries */
1210                 if (MUTEX_HELD(&zp->z_lock) || zp->z_is_ctldir)
1211                         continue;
1212
1213                 if (igrab(ZTOI(zp)) == NULL)
1214                         continue;
1215
1216                 zp_array[j] = zp;
1217                 j++;
1218         }
1219         mutex_exit(&zfsvfs->z_znodes_lock);
1220
1221         for (i = 0; i < j; i++) {
1222                 zp = zp_array[i];
1223
1224                 ASSERT3P(zp, !=, NULL);
1225                 d_prune_aliases(ZTOI(zp));
1226
1227                 if (atomic_read(&ZTOI(zp)->i_count) == 1)
1228                         objects++;
1229
1230                 zrele(zp);
1231         }
1232
1233         vmem_free(zp_array, max_array * sizeof (znode_t *));
1234
1235         return (objects);
1236 }
1237
1238 /*
1239  * The ARC has requested that the filesystem drop entries from the dentry
1240  * and inode caches.  This can occur when the ARC needs to free meta data
1241  * blocks but can't because they are all pinned by entries in these caches.
1242  */
1243 int
1244 zfs_prune(struct super_block *sb, unsigned long nr_to_scan, int *objects)
1245 {
1246         zfsvfs_t *zfsvfs = sb->s_fs_info;
1247         int error = 0;
1248         struct shrinker *shrinker = &sb->s_shrink;
1249         struct shrink_control sc = {
1250                 .nr_to_scan = nr_to_scan,
1251                 .gfp_mask = GFP_KERNEL,
1252         };
1253
1254         if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
1255                 return (error);
1256
1257 #if defined(HAVE_SPLIT_SHRINKER_CALLBACK) && \
1258         defined(SHRINK_CONTROL_HAS_NID) && \
1259         defined(SHRINKER_NUMA_AWARE)
1260         if (sb->s_shrink.flags & SHRINKER_NUMA_AWARE) {
1261                 *objects = 0;
1262                 for_each_online_node(sc.nid) {
1263                         *objects += (*shrinker->scan_objects)(shrinker, &sc);
1264                         /*
1265                          * reset sc.nr_to_scan, modified by
1266                          * scan_objects == super_cache_scan
1267                          */
1268                         sc.nr_to_scan = nr_to_scan;
1269                 }
1270         } else {
1271                         *objects = (*shrinker->scan_objects)(shrinker, &sc);
1272         }
1273
1274 #elif defined(HAVE_SPLIT_SHRINKER_CALLBACK)
1275         *objects = (*shrinker->scan_objects)(shrinker, &sc);
1276 #elif defined(HAVE_SINGLE_SHRINKER_CALLBACK)
1277         *objects = (*shrinker->shrink)(shrinker, &sc);
1278 #elif defined(HAVE_D_PRUNE_ALIASES)
1279 #define D_PRUNE_ALIASES_IS_DEFAULT
1280         *objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1281 #else
1282 #error "No available dentry and inode cache pruning mechanism."
1283 #endif
1284
1285 #if defined(HAVE_D_PRUNE_ALIASES) && !defined(D_PRUNE_ALIASES_IS_DEFAULT)
1286 #undef  D_PRUNE_ALIASES_IS_DEFAULT
1287         /*
1288          * Fall back to zfs_prune_aliases if the kernel's per-superblock
1289          * shrinker couldn't free anything, possibly due to the inodes being
1290          * allocated in a different memcg.
1291          */
1292         if (*objects == 0)
1293                 *objects = zfs_prune_aliases(zfsvfs, nr_to_scan);
1294 #endif
1295
1296         zfs_exit(zfsvfs, FTAG);
1297
1298         dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
1299             "pruning, nr_to_scan=%lu objects=%d error=%d\n",
1300             nr_to_scan, *objects, error);
1301
1302         return (error);
1303 }
1304
1305 /*
1306  * Teardown the zfsvfs_t.
1307  *
1308  * Note, if 'unmounting' is FALSE, we return with the 'z_teardown_lock'
1309  * and 'z_teardown_inactive_lock' held.
1310  */
1311 static int
1312 zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
1313 {
1314         znode_t *zp;
1315
1316         zfs_unlinked_drain_stop_wait(zfsvfs);
1317
1318         /*
1319          * If someone has not already unmounted this file system,
1320          * drain the zrele_taskq to ensure all active references to the
1321          * zfsvfs_t have been handled only then can it be safely destroyed.
1322          */
1323         if (zfsvfs->z_os) {
1324                 /*
1325                  * If we're unmounting we have to wait for the list to
1326                  * drain completely.
1327                  *
1328                  * If we're not unmounting there's no guarantee the list
1329                  * will drain completely, but iputs run from the taskq
1330                  * may add the parents of dir-based xattrs to the taskq
1331                  * so we want to wait for these.
1332                  *
1333                  * We can safely check z_all_znodes for being empty because the
1334                  * VFS has already blocked operations which add to it.
1335                  */
1336                 int round = 0;
1337                 while (!list_is_empty(&zfsvfs->z_all_znodes)) {
1338                         taskq_wait_outstanding(dsl_pool_zrele_taskq(
1339                             dmu_objset_pool(zfsvfs->z_os)), 0);
1340                         if (++round > 1 && !unmounting)
1341                                 break;
1342                 }
1343         }
1344
1345         ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);
1346
1347         if (!unmounting) {
1348                 /*
1349                  * We purge the parent filesystem's super block as the
1350                  * parent filesystem and all of its snapshots have their
1351                  * inode's super block set to the parent's filesystem's
1352                  * super block.  Note,  'z_parent' is self referential
1353                  * for non-snapshots.
1354                  */
1355                 shrink_dcache_sb(zfsvfs->z_parent->z_sb);
1356         }
1357
1358         /*
1359          * Close the zil. NB: Can't close the zil while zfs_inactive
1360          * threads are blocked as zil_close can call zfs_inactive.
1361          */
1362         if (zfsvfs->z_log) {
1363                 zil_close(zfsvfs->z_log);
1364                 zfsvfs->z_log = NULL;
1365         }
1366
1367         rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_WRITER);
1368
1369         /*
1370          * If we are not unmounting (ie: online recv) and someone already
1371          * unmounted this file system while we were doing the switcheroo,
1372          * or a reopen of z_os failed then just bail out now.
1373          */
1374         if (!unmounting && (zfsvfs->z_unmounted || zfsvfs->z_os == NULL)) {
1375                 rw_exit(&zfsvfs->z_teardown_inactive_lock);
1376                 ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1377                 return (SET_ERROR(EIO));
1378         }
1379
1380         /*
1381          * At this point there are no VFS ops active, and any new VFS ops
1382          * will fail with EIO since we have z_teardown_lock for writer (only
1383          * relevant for forced unmount).
1384          *
1385          * Release all holds on dbufs. We also grab an extra reference to all
1386          * the remaining inodes so that the kernel does not attempt to free
1387          * any inodes of a suspended fs. This can cause deadlocks since the
1388          * zfs_resume_fs() process may involve starting threads, which might
1389          * attempt to free unreferenced inodes to free up memory for the new
1390          * thread.
1391          */
1392         if (!unmounting) {
1393                 mutex_enter(&zfsvfs->z_znodes_lock);
1394                 for (zp = list_head(&zfsvfs->z_all_znodes); zp != NULL;
1395                     zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1396                         if (zp->z_sa_hdl)
1397                                 zfs_znode_dmu_fini(zp);
1398                         if (igrab(ZTOI(zp)) != NULL)
1399                                 zp->z_suspended = B_TRUE;
1400
1401                 }
1402                 mutex_exit(&zfsvfs->z_znodes_lock);
1403         }
1404
1405         /*
1406          * If we are unmounting, set the unmounted flag and let new VFS ops
1407          * unblock.  zfs_inactive will have the unmounted behavior, and all
1408          * other VFS ops will fail with EIO.
1409          */
1410         if (unmounting) {
1411                 zfsvfs->z_unmounted = B_TRUE;
1412                 rw_exit(&zfsvfs->z_teardown_inactive_lock);
1413                 ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1414         }
1415
1416         /*
1417          * z_os will be NULL if there was an error in attempting to reopen
1418          * zfsvfs, so just return as the properties had already been
1419          *
1420          * unregistered and cached data had been evicted before.
1421          */
1422         if (zfsvfs->z_os == NULL)
1423                 return (0);
1424
1425         /*
1426          * Unregister properties.
1427          */
1428         zfs_unregister_callbacks(zfsvfs);
1429
1430         /*
1431          * Evict cached data. We must write out any dirty data before
1432          * disowning the dataset.
1433          */
1434         objset_t *os = zfsvfs->z_os;
1435         boolean_t os_dirty = B_FALSE;
1436         for (int t = 0; t < TXG_SIZE; t++) {
1437                 if (dmu_objset_is_dirty(os, t)) {
1438                         os_dirty = B_TRUE;
1439                         break;
1440                 }
1441         }
1442         if (!zfs_is_readonly(zfsvfs) && os_dirty) {
1443                 txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1444         }
1445         dmu_objset_evict_dbufs(zfsvfs->z_os);
1446         dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1447         dsl_dir_cancel_waiters(dd);
1448
1449         return (0);
1450 }
1451
1452 #if defined(HAVE_SUPER_SETUP_BDI_NAME)
1453 atomic_long_t zfs_bdi_seq = ATOMIC_LONG_INIT(0);
1454 #endif
1455
1456 int
1457 zfs_domount(struct super_block *sb, zfs_mnt_t *zm, int silent)
1458 {
1459         const char *osname = zm->mnt_osname;
1460         struct inode *root_inode = NULL;
1461         uint64_t recordsize;
1462         int error = 0;
1463         zfsvfs_t *zfsvfs = NULL;
1464         vfs_t *vfs = NULL;
1465         int canwrite;
1466         int dataset_visible_zone;
1467
1468         ASSERT(zm);
1469         ASSERT(osname);
1470
1471         dataset_visible_zone = zone_dataset_visible(osname, &canwrite);
1472
1473         /*
1474          * Refuse to mount a filesystem if we are in a namespace and the
1475          * dataset is not visible or writable in that namespace.
1476          */
1477         if (!INGLOBALZONE(curproc) &&
1478             (!dataset_visible_zone || !canwrite)) {
1479                 return (SET_ERROR(EPERM));
1480         }
1481
1482         error = zfsvfs_parse_options(zm->mnt_data, &vfs);
1483         if (error)
1484                 return (error);
1485
1486         /*
1487          * If a non-writable filesystem is being mounted without the
1488          * read-only flag, pretend it was set, as done for snapshots.
1489          */
1490         if (!canwrite)
1491                 vfs->vfs_readonly = B_TRUE;
1492
1493         error = zfsvfs_create(osname, vfs->vfs_readonly, &zfsvfs);
1494         if (error) {
1495                 zfsvfs_vfs_free(vfs);
1496                 goto out;
1497         }
1498
1499         if ((error = dsl_prop_get_integer(osname, "recordsize",
1500             &recordsize, NULL))) {
1501                 zfsvfs_vfs_free(vfs);
1502                 goto out;
1503         }
1504
1505         vfs->vfs_data = zfsvfs;
1506         zfsvfs->z_vfs = vfs;
1507         zfsvfs->z_sb = sb;
1508         sb->s_fs_info = zfsvfs;
1509         sb->s_magic = ZFS_SUPER_MAGIC;
1510         sb->s_maxbytes = MAX_LFS_FILESIZE;
1511         sb->s_time_gran = 1;
1512         sb->s_blocksize = recordsize;
1513         sb->s_blocksize_bits = ilog2(recordsize);
1514
1515         error = -zpl_bdi_setup(sb, "zfs");
1516         if (error)
1517                 goto out;
1518
1519         sb->s_bdi->ra_pages = 0;
1520
1521         /* Set callback operations for the file system. */
1522         sb->s_op = &zpl_super_operations;
1523         sb->s_xattr = zpl_xattr_handlers;
1524         sb->s_export_op = &zpl_export_operations;
1525
1526         /* Set features for file system. */
1527         zfs_set_fuid_feature(zfsvfs);
1528
1529         if (dmu_objset_is_snapshot(zfsvfs->z_os)) {
1530                 uint64_t pval;
1531
1532                 atime_changed_cb(zfsvfs, B_FALSE);
1533                 readonly_changed_cb(zfsvfs, B_TRUE);
1534                 if ((error = dsl_prop_get_integer(osname,
1535                     "xattr", &pval, NULL)))
1536                         goto out;
1537                 xattr_changed_cb(zfsvfs, pval);
1538                 if ((error = dsl_prop_get_integer(osname,
1539                     "acltype", &pval, NULL)))
1540                         goto out;
1541                 acltype_changed_cb(zfsvfs, pval);
1542                 zfsvfs->z_issnap = B_TRUE;
1543                 zfsvfs->z_os->os_sync = ZFS_SYNC_DISABLED;
1544                 zfsvfs->z_snap_defer_time = jiffies;
1545
1546                 mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
1547                 dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
1548                 mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
1549         } else {
1550                 if ((error = zfsvfs_setup(zfsvfs, B_TRUE)))
1551                         goto out;
1552         }
1553
1554         /* Allocate a root inode for the filesystem. */
1555         error = zfs_root(zfsvfs, &root_inode);
1556         if (error) {
1557                 (void) zfs_umount(sb);
1558                 zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1559                 goto out;
1560         }
1561
1562         /* Allocate a root dentry for the filesystem */
1563         sb->s_root = d_make_root(root_inode);
1564         if (sb->s_root == NULL) {
1565                 (void) zfs_umount(sb);
1566                 zfsvfs = NULL; /* avoid double-free; first in zfs_umount */
1567                 error = SET_ERROR(ENOMEM);
1568                 goto out;
1569         }
1570
1571         if (!zfsvfs->z_issnap)
1572                 zfsctl_create(zfsvfs);
1573
1574         zfsvfs->z_arc_prune = arc_add_prune_callback(zpl_prune_sb, sb);
1575 out:
1576         if (error) {
1577                 if (zfsvfs != NULL) {
1578                         dmu_objset_disown(zfsvfs->z_os, B_TRUE, zfsvfs);
1579                         zfsvfs_free(zfsvfs);
1580                 }
1581                 /*
1582                  * make sure we don't have dangling sb->s_fs_info which
1583                  * zfs_preumount will use.
1584                  */
1585                 sb->s_fs_info = NULL;
1586         }
1587
1588         return (error);
1589 }
1590
1591 /*
1592  * Called when an unmount is requested and certain sanity checks have
1593  * already passed.  At this point no dentries or inodes have been reclaimed
1594  * from their respective caches.  We drop the extra reference on the .zfs
1595  * control directory to allow everything to be reclaimed.  All snapshots
1596  * must already have been unmounted to reach this point.
1597  */
1598 void
1599 zfs_preumount(struct super_block *sb)
1600 {
1601         zfsvfs_t *zfsvfs = sb->s_fs_info;
1602
1603         /* zfsvfs is NULL when zfs_domount fails during mount */
1604         if (zfsvfs) {
1605                 zfs_unlinked_drain_stop_wait(zfsvfs);
1606                 zfsctl_destroy(sb->s_fs_info);
1607                 /*
1608                  * Wait for zrele_async before entering evict_inodes in
1609                  * generic_shutdown_super. The reason we must finish before
1610                  * evict_inodes is when lazytime is on, or when zfs_purgedir
1611                  * calls zfs_zget, zrele would bump i_count from 0 to 1. This
1612                  * would race with the i_count check in evict_inodes. This means
1613                  * it could destroy the inode while we are still using it.
1614                  *
1615                  * We wait for two passes. xattr directories in the first pass
1616                  * may add xattr entries in zfs_purgedir, so in the second pass
1617                  * we wait for them. We don't use taskq_wait here because it is
1618                  * a pool wide taskq. Other mounted filesystems can constantly
1619                  * do zrele_async and there's no guarantee when taskq will be
1620                  * empty.
1621                  */
1622                 taskq_wait_outstanding(dsl_pool_zrele_taskq(
1623                     dmu_objset_pool(zfsvfs->z_os)), 0);
1624                 taskq_wait_outstanding(dsl_pool_zrele_taskq(
1625                     dmu_objset_pool(zfsvfs->z_os)), 0);
1626         }
1627 }
1628
1629 /*
1630  * Called once all other unmount released tear down has occurred.
1631  * It is our responsibility to release any remaining infrastructure.
1632  */
1633 int
1634 zfs_umount(struct super_block *sb)
1635 {
1636         zfsvfs_t *zfsvfs = sb->s_fs_info;
1637         objset_t *os;
1638
1639         if (zfsvfs->z_arc_prune != NULL)
1640                 arc_remove_prune_callback(zfsvfs->z_arc_prune);
1641         VERIFY(zfsvfs_teardown(zfsvfs, B_TRUE) == 0);
1642         os = zfsvfs->z_os;
1643         zpl_bdi_destroy(sb);
1644
1645         /*
1646          * z_os will be NULL if there was an error in
1647          * attempting to reopen zfsvfs.
1648          */
1649         if (os != NULL) {
1650                 /*
1651                  * Unset the objset user_ptr.
1652                  */
1653                 mutex_enter(&os->os_user_ptr_lock);
1654                 dmu_objset_set_user(os, NULL);
1655                 mutex_exit(&os->os_user_ptr_lock);
1656
1657                 /*
1658                  * Finally release the objset
1659                  */
1660                 dmu_objset_disown(os, B_TRUE, zfsvfs);
1661         }
1662
1663         zfsvfs_free(zfsvfs);
1664         sb->s_fs_info = NULL;
1665         return (0);
1666 }
1667
1668 int
1669 zfs_remount(struct super_block *sb, int *flags, zfs_mnt_t *zm)
1670 {
1671         zfsvfs_t *zfsvfs = sb->s_fs_info;
1672         vfs_t *vfsp;
1673         boolean_t issnap = dmu_objset_is_snapshot(zfsvfs->z_os);
1674         int error;
1675
1676         if ((issnap || !spa_writeable(dmu_objset_spa(zfsvfs->z_os))) &&
1677             !(*flags & SB_RDONLY)) {
1678                 *flags |= SB_RDONLY;
1679                 return (EROFS);
1680         }
1681
1682         error = zfsvfs_parse_options(zm->mnt_data, &vfsp);
1683         if (error)
1684                 return (error);
1685
1686         if (!zfs_is_readonly(zfsvfs) && (*flags & SB_RDONLY))
1687                 txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
1688
1689         zfs_unregister_callbacks(zfsvfs);
1690         zfsvfs_vfs_free(zfsvfs->z_vfs);
1691
1692         vfsp->vfs_data = zfsvfs;
1693         zfsvfs->z_vfs = vfsp;
1694         if (!issnap)
1695                 (void) zfs_register_callbacks(vfsp);
1696
1697         return (error);
1698 }
1699
1700 int
1701 zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp)
1702 {
1703         zfsvfs_t        *zfsvfs = sb->s_fs_info;
1704         znode_t         *zp;
1705         uint64_t        object = 0;
1706         uint64_t        fid_gen = 0;
1707         uint64_t        gen_mask;
1708         uint64_t        zp_gen;
1709         int             i, err;
1710
1711         *ipp = NULL;
1712
1713         if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
1714                 zfid_short_t    *zfid = (zfid_short_t *)fidp;
1715
1716                 for (i = 0; i < sizeof (zfid->zf_object); i++)
1717                         object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);
1718
1719                 for (i = 0; i < sizeof (zfid->zf_gen); i++)
1720                         fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
1721         } else {
1722                 return (SET_ERROR(EINVAL));
1723         }
1724
1725         /* LONG_FID_LEN means snapdirs */
1726         if (fidp->fid_len == LONG_FID_LEN) {
1727                 zfid_long_t     *zlfid = (zfid_long_t *)fidp;
1728                 uint64_t        objsetid = 0;
1729                 uint64_t        setgen = 0;
1730
1731                 for (i = 0; i < sizeof (zlfid->zf_setid); i++)
1732                         objsetid |= ((uint64_t)zlfid->zf_setid[i]) << (8 * i);
1733
1734                 for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
1735                         setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i);
1736
1737                 if (objsetid != ZFSCTL_INO_SNAPDIRS - object) {
1738                         dprintf("snapdir fid: objsetid (%llu) != "
1739                             "ZFSCTL_INO_SNAPDIRS (%llu) - object (%llu)\n",
1740                             objsetid, ZFSCTL_INO_SNAPDIRS, object);
1741
1742                         return (SET_ERROR(EINVAL));
1743                 }
1744
1745                 if (fid_gen > 1 || setgen != 0) {
1746                         dprintf("snapdir fid: fid_gen (%llu) and setgen "
1747                             "(%llu)\n", fid_gen, setgen);
1748                         return (SET_ERROR(EINVAL));
1749                 }
1750
1751                 return (zfsctl_snapdir_vget(sb, objsetid, fid_gen, ipp));
1752         }
1753
1754         if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
1755                 return (err);
1756         /* A zero fid_gen means we are in the .zfs control directories */
1757         if (fid_gen == 0 &&
1758             (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) {
1759                 *ipp = zfsvfs->z_ctldir;
1760                 ASSERT(*ipp != NULL);
1761                 if (object == ZFSCTL_INO_SNAPDIR) {
1762                         VERIFY(zfsctl_root_lookup(*ipp, "snapshot", ipp,
1763                             0, kcred, NULL, NULL) == 0);
1764                 } else {
1765                         /*
1766                          * Must have an existing ref, so igrab()
1767                          * cannot return NULL
1768                          */
1769                         VERIFY3P(igrab(*ipp), !=, NULL);
1770                 }
1771                 zfs_exit(zfsvfs, FTAG);
1772                 return (0);
1773         }
1774
1775         gen_mask = -1ULL >> (64 - 8 * i);
1776
1777         dprintf("getting %llu [%llu mask %llx]\n", object, fid_gen, gen_mask);
1778         if ((err = zfs_zget(zfsvfs, object, &zp))) {
1779                 zfs_exit(zfsvfs, FTAG);
1780                 return (err);
1781         }
1782
1783         /* Don't export xattr stuff */
1784         if (zp->z_pflags & ZFS_XATTR) {
1785                 zrele(zp);
1786                 zfs_exit(zfsvfs, FTAG);
1787                 return (SET_ERROR(ENOENT));
1788         }
1789
1790         (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs), &zp_gen,
1791             sizeof (uint64_t));
1792         zp_gen = zp_gen & gen_mask;
1793         if (zp_gen == 0)
1794                 zp_gen = 1;
1795         if ((fid_gen == 0) && (zfsvfs->z_root == object))
1796                 fid_gen = zp_gen;
1797         if (zp->z_unlinked || zp_gen != fid_gen) {
1798                 dprintf("znode gen (%llu) != fid gen (%llu)\n", zp_gen,
1799                     fid_gen);
1800                 zrele(zp);
1801                 zfs_exit(zfsvfs, FTAG);
1802                 return (SET_ERROR(ENOENT));
1803         }
1804
1805         *ipp = ZTOI(zp);
1806         if (*ipp)
1807                 zfs_znode_update_vfs(ITOZ(*ipp));
1808
1809         zfs_exit(zfsvfs, FTAG);
1810         return (0);
1811 }
1812
1813 /*
1814  * Block out VFS ops and close zfsvfs_t
1815  *
1816  * Note, if successful, then we return with the 'z_teardown_lock' and
1817  * 'z_teardown_inactive_lock' write held.  We leave ownership of the underlying
1818  * dataset and objset intact so that they can be atomically handed off during
1819  * a subsequent rollback or recv operation and the resume thereafter.
1820  */
1821 int
1822 zfs_suspend_fs(zfsvfs_t *zfsvfs)
1823 {
1824         int error;
1825
1826         if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
1827                 return (error);
1828
1829         return (0);
1830 }
1831
1832 /*
1833  * Rebuild SA and release VOPs.  Note that ownership of the underlying dataset
1834  * is an invariant across any of the operations that can be performed while the
1835  * filesystem was suspended.  Whether it succeeded or failed, the preconditions
1836  * are the same: the relevant objset and associated dataset are owned by
1837  * zfsvfs, held, and long held on entry.
1838  */
1839 int
1840 zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1841 {
1842         int err, err2;
1843         znode_t *zp;
1844
1845         ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1846         ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1847
1848         /*
1849          * We already own this, so just update the objset_t, as the one we
1850          * had before may have been evicted.
1851          */
1852         objset_t *os;
1853         VERIFY3P(ds->ds_owner, ==, zfsvfs);
1854         VERIFY(dsl_dataset_long_held(ds));
1855         dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1856         dsl_pool_config_enter(dp, FTAG);
1857         VERIFY0(dmu_objset_from_ds(ds, &os));
1858         dsl_pool_config_exit(dp, FTAG);
1859
1860         err = zfsvfs_init(zfsvfs, os);
1861         if (err != 0)
1862                 goto bail;
1863
1864         ds->ds_dir->dd_activity_cancelled = B_FALSE;
1865         VERIFY(zfsvfs_setup(zfsvfs, B_FALSE) == 0);
1866
1867         zfs_set_fuid_feature(zfsvfs);
1868         zfsvfs->z_rollback_time = jiffies;
1869
1870         /*
1871          * Attempt to re-establish all the active inodes with their
1872          * dbufs.  If a zfs_rezget() fails, then we unhash the inode
1873          * and mark it stale.  This prevents a collision if a new
1874          * inode/object is created which must use the same inode
1875          * number.  The stale inode will be be released when the
1876          * VFS prunes the dentry holding the remaining references
1877          * on the stale inode.
1878          */
1879         mutex_enter(&zfsvfs->z_znodes_lock);
1880         for (zp = list_head(&zfsvfs->z_all_znodes); zp;
1881             zp = list_next(&zfsvfs->z_all_znodes, zp)) {
1882                 err2 = zfs_rezget(zp);
1883                 if (err2) {
1884                         zpl_d_drop_aliases(ZTOI(zp));
1885                         remove_inode_hash(ZTOI(zp));
1886                 }
1887
1888                 /* see comment in zfs_suspend_fs() */
1889                 if (zp->z_suspended) {
1890                         zfs_zrele_async(zp);
1891                         zp->z_suspended = B_FALSE;
1892                 }
1893         }
1894         mutex_exit(&zfsvfs->z_znodes_lock);
1895
1896         if (!zfs_is_readonly(zfsvfs) && !zfsvfs->z_unmounted) {
1897                 /*
1898                  * zfs_suspend_fs() could have interrupted freeing
1899                  * of dnodes. We need to restart this freeing so
1900                  * that we don't "leak" the space.
1901                  */
1902                 zfs_unlinked_drain(zfsvfs);
1903         }
1904
1905         /*
1906          * Most of the time zfs_suspend_fs is used for changing the contents
1907          * of the underlying dataset. ZFS rollback and receive operations
1908          * might create files for which negative dentries are present in
1909          * the cache. Since walking the dcache would require a lot of GPL-only
1910          * code duplication, it's much easier on these rather rare occasions
1911          * just to flush the whole dcache for the given dataset/filesystem.
1912          */
1913         shrink_dcache_sb(zfsvfs->z_sb);
1914
1915 bail:
1916         if (err != 0)
1917                 zfsvfs->z_unmounted = B_TRUE;
1918
1919         /* release the VFS ops */
1920         rw_exit(&zfsvfs->z_teardown_inactive_lock);
1921         ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1922
1923         if (err != 0) {
1924                 /*
1925                  * Since we couldn't setup the sa framework, try to force
1926                  * unmount this file system.
1927                  */
1928                 if (zfsvfs->z_os)
1929                         (void) zfs_umount(zfsvfs->z_sb);
1930         }
1931         return (err);
1932 }
1933
1934 /*
1935  * Release VOPs and unmount a suspended filesystem.
1936  */
1937 int
1938 zfs_end_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
1939 {
1940         ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
1941         ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));
1942
1943         /*
1944          * We already own this, so just hold and rele it to update the
1945          * objset_t, as the one we had before may have been evicted.
1946          */
1947         objset_t *os;
1948         VERIFY3P(ds->ds_owner, ==, zfsvfs);
1949         VERIFY(dsl_dataset_long_held(ds));
1950         dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
1951         dsl_pool_config_enter(dp, FTAG);
1952         VERIFY0(dmu_objset_from_ds(ds, &os));
1953         dsl_pool_config_exit(dp, FTAG);
1954         zfsvfs->z_os = os;
1955
1956         /* release the VOPs */
1957         rw_exit(&zfsvfs->z_teardown_inactive_lock);
1958         ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
1959
1960         /*
1961          * Try to force unmount this file system.
1962          */
1963         (void) zfs_umount(zfsvfs->z_sb);
1964         zfsvfs->z_unmounted = B_TRUE;
1965         return (0);
1966 }
1967
1968 /*
1969  * Automounted snapshots rely on periodic revalidation
1970  * to defer snapshots from being automatically unmounted.
1971  */
1972
1973 inline void
1974 zfs_exit_fs(zfsvfs_t *zfsvfs)
1975 {
1976         if (!zfsvfs->z_issnap)
1977                 return;
1978
1979         if (time_after(jiffies, zfsvfs->z_snap_defer_time +
1980             MAX(zfs_expire_snapshot * HZ / 2, HZ))) {
1981                 zfsvfs->z_snap_defer_time = jiffies;
1982                 zfsctl_snapshot_unmount_delay(zfsvfs->z_os->os_spa,
1983                     dmu_objset_id(zfsvfs->z_os),
1984                     zfs_expire_snapshot);
1985         }
1986 }
1987
1988 int
1989 zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
1990 {
1991         int error;
1992         objset_t *os = zfsvfs->z_os;
1993         dmu_tx_t *tx;
1994
1995         if (newvers < ZPL_VERSION_INITIAL || newvers > ZPL_VERSION)
1996                 return (SET_ERROR(EINVAL));
1997
1998         if (newvers < zfsvfs->z_version)
1999                 return (SET_ERROR(EINVAL));
2000
2001         if (zfs_spa_version_map(newvers) >
2002             spa_version(dmu_objset_spa(zfsvfs->z_os)))
2003                 return (SET_ERROR(ENOTSUP));
2004
2005         tx = dmu_tx_create(os);
2006         dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
2007         if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2008                 dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
2009                     ZFS_SA_ATTRS);
2010                 dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
2011         }
2012         error = dmu_tx_assign(tx, TXG_WAIT);
2013         if (error) {
2014                 dmu_tx_abort(tx);
2015                 return (error);
2016         }
2017
2018         error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
2019             8, 1, &newvers, tx);
2020
2021         if (error) {
2022                 dmu_tx_commit(tx);
2023                 return (error);
2024         }
2025
2026         if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
2027                 uint64_t sa_obj;
2028
2029                 ASSERT3U(spa_version(dmu_objset_spa(zfsvfs->z_os)), >=,
2030                     SPA_VERSION_SA);
2031                 sa_obj = zap_create(os, DMU_OT_SA_MASTER_NODE,
2032                     DMU_OT_NONE, 0, tx);
2033
2034                 error = zap_add(os, MASTER_NODE_OBJ,
2035                     ZFS_SA_ATTRS, 8, 1, &sa_obj, tx);
2036                 ASSERT0(error);
2037
2038                 VERIFY(0 == sa_set_sa_object(os, sa_obj));
2039                 sa_register_update_callback(os, zfs_sa_upgrade);
2040         }
2041
2042         spa_history_log_internal_ds(dmu_objset_ds(os), "upgrade", tx,
2043             "from %llu to %llu", zfsvfs->z_version, newvers);
2044
2045         dmu_tx_commit(tx);
2046
2047         zfsvfs->z_version = newvers;
2048         os->os_version = newvers;
2049
2050         zfs_set_fuid_feature(zfsvfs);
2051
2052         return (0);
2053 }
2054
2055 /*
2056  * Return true if the corresponding vfs's unmounted flag is set.
2057  * Otherwise return false.
2058  * If this function returns true we know VFS unmount has been initiated.
2059  */
2060 boolean_t
2061 zfs_get_vfs_flag_unmounted(objset_t *os)
2062 {
2063         zfsvfs_t *zfvp;
2064         boolean_t unmounted = B_FALSE;
2065
2066         ASSERT(dmu_objset_type(os) == DMU_OST_ZFS);
2067
2068         mutex_enter(&os->os_user_ptr_lock);
2069         zfvp = dmu_objset_get_user(os);
2070         if (zfvp != NULL && zfvp->z_unmounted)
2071                 unmounted = B_TRUE;
2072         mutex_exit(&os->os_user_ptr_lock);
2073
2074         return (unmounted);
2075 }
2076
2077 void
2078 zfsvfs_update_fromname(const char *oldname, const char *newname)
2079 {
2080         /*
2081          * We don't need to do anything here, the devname is always current by
2082          * virtue of zfsvfs->z_sb->s_op->show_devname.
2083          */
2084         (void) oldname, (void) newname;
2085 }
2086
2087 void
2088 zfs_init(void)
2089 {
2090         zfsctl_init();
2091         zfs_znode_init();
2092         dmu_objset_register_type(DMU_OST_ZFS, zpl_get_file_info);
2093         register_filesystem(&zpl_fs_type);
2094 #ifdef HAVE_VFS_FILE_OPERATIONS_EXTEND
2095         register_fo_extend(&zpl_file_operations);
2096 #endif
2097 }
2098
2099 void
2100 zfs_fini(void)
2101 {
2102         /*
2103          * we don't use outstanding because zpl_posix_acl_free might add more.
2104          */
2105         taskq_wait(system_delay_taskq);
2106         taskq_wait(system_taskq);
2107 #ifdef HAVE_VFS_FILE_OPERATIONS_EXTEND
2108         unregister_fo_extend(&zpl_file_operations);
2109 #endif
2110         unregister_filesystem(&zpl_fs_type);
2111         zfs_znode_fini();
2112         zfsctl_fini();
2113 }
2114
2115 #if defined(_KERNEL)
2116 EXPORT_SYMBOL(zfs_suspend_fs);
2117 EXPORT_SYMBOL(zfs_resume_fs);
2118 EXPORT_SYMBOL(zfs_set_version);
2119 EXPORT_SYMBOL(zfsvfs_create);
2120 EXPORT_SYMBOL(zfsvfs_free);
2121 EXPORT_SYMBOL(zfs_is_readonly);
2122 EXPORT_SYMBOL(zfs_domount);
2123 EXPORT_SYMBOL(zfs_preumount);
2124 EXPORT_SYMBOL(zfs_umount);
2125 EXPORT_SYMBOL(zfs_remount);
2126 EXPORT_SYMBOL(zfs_statvfs);
2127 EXPORT_SYMBOL(zfs_vget);
2128 EXPORT_SYMBOL(zfs_prune);
2129 #endif