The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/os/freebsd/zfs/zfs_dir.c

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    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 /*
   23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   24  * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
   25  * Copyright 2017 Nexenta Systems, Inc.
   26  */
   27 
   28 #include <sys/types.h>
   29 #include <sys/param.h>
   30 #include <sys/time.h>
   31 #include <sys/systm.h>
   32 #include <sys/sysmacros.h>
   33 #include <sys/resource.h>
   34 #include <sys/vfs.h>
   35 #include <sys/vnode.h>
   36 #include <sys/file.h>
   37 #include <sys/kmem.h>
   38 #include <sys/uio.h>
   39 #include <sys/cmn_err.h>
   40 #include <sys/errno.h>
   41 #include <sys/stat.h>
   42 #include <sys/unistd.h>
   43 #include <sys/sunddi.h>
   44 #include <sys/random.h>
   45 #include <sys/policy.h>
   46 #include <sys/condvar.h>
   47 #include <sys/callb.h>
   48 #include <sys/smp.h>
   49 #include <sys/zfs_dir.h>
   50 #include <sys/zfs_acl.h>
   51 #include <sys/fs/zfs.h>
   52 #include <sys/zap.h>
   53 #include <sys/dmu.h>
   54 #include <sys/atomic.h>
   55 #include <sys/zfs_ctldir.h>
   56 #include <sys/zfs_fuid.h>
   57 #include <sys/sa.h>
   58 #include <sys/zfs_sa.h>
   59 #include <sys/dmu_objset.h>
   60 #include <sys/dsl_dir.h>
   61 
   62 #include <sys/ccompat.h>
   63 
   64 /*
   65  * zfs_match_find() is used by zfs_dirent_lookup() to perform zap lookups
   66  * of names after deciding which is the appropriate lookup interface.
   67  */
   68 static int
   69 zfs_match_find(zfsvfs_t *zfsvfs, znode_t *dzp, const char *name,
   70     matchtype_t mt, uint64_t *zoid)
   71 {
   72         int error;
   73 
   74         if (zfsvfs->z_norm) {
   75 
   76                 /*
   77                  * In the non-mixed case we only expect there would ever
   78                  * be one match, but we need to use the normalizing lookup.
   79                  */
   80                 error = zap_lookup_norm(zfsvfs->z_os, dzp->z_id, name, 8, 1,
   81                     zoid, mt, NULL, 0, NULL);
   82         } else {
   83                 error = zap_lookup(zfsvfs->z_os, dzp->z_id, name, 8, 1, zoid);
   84         }
   85         *zoid = ZFS_DIRENT_OBJ(*zoid);
   86 
   87         return (error);
   88 }
   89 
   90 /*
   91  * Look up a directory entry under a locked vnode.
   92  * dvp being locked gives us a guarantee that there are no concurrent
   93  * modification of the directory and, thus, if a node can be found in
   94  * the directory, then it must not be unlinked.
   95  *
   96  * Input arguments:
   97  *      dzp     - znode for directory
   98  *      name    - name of entry to lock
   99  *      flag    - ZNEW: if the entry already exists, fail with EEXIST.
  100  *                ZEXISTS: if the entry does not exist, fail with ENOENT.
  101  *                ZXATTR: we want dzp's xattr directory
  102  *
  103  * Output arguments:
  104  *      zpp     - pointer to the znode for the entry (NULL if there isn't one)
  105  *
  106  * Return value: 0 on success or errno on failure.
  107  *
  108  * NOTE: Always checks for, and rejects, '.' and '..'.
  109  */
  110 int
  111 zfs_dirent_lookup(znode_t *dzp, const char *name, znode_t **zpp, int flag)
  112 {
  113         zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
  114         znode_t         *zp;
  115         matchtype_t     mt = 0;
  116         uint64_t        zoid;
  117         int             error = 0;
  118 
  119         if (zfsvfs->z_replay == B_FALSE)
  120                 ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  121 
  122         *zpp = NULL;
  123 
  124         /*
  125          * Verify that we are not trying to lock '.', '..', or '.zfs'
  126          */
  127         if (name[0] == '.' &&
  128             (((name[1] == '\0') || (name[1] == '.' && name[2] == '\0')) ||
  129             (zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0)))
  130                 return (SET_ERROR(EEXIST));
  131 
  132         /*
  133          * Case sensitivity and normalization preferences are set when
  134          * the file system is created.  These are stored in the
  135          * zfsvfs->z_case and zfsvfs->z_norm fields.  These choices
  136          * affect how we perform zap lookups.
  137          *
  138          * When matching we may need to normalize & change case according to
  139          * FS settings.
  140          *
  141          * Note that a normalized match is necessary for a case insensitive
  142          * filesystem when the lookup request is not exact because normalization
  143          * can fold case independent of normalizing code point sequences.
  144          *
  145          * See the table above zfs_dropname().
  146          */
  147         if (zfsvfs->z_norm != 0) {
  148                 mt = MT_NORMALIZE;
  149 
  150                 /*
  151                  * Determine if the match needs to honor the case specified in
  152                  * lookup, and if so keep track of that so that during
  153                  * normalization we don't fold case.
  154                  */
  155                 if (zfsvfs->z_case == ZFS_CASE_MIXED) {
  156                         mt |= MT_MATCH_CASE;
  157                 }
  158         }
  159 
  160         /*
  161          * Only look in or update the DNLC if we are looking for the
  162          * name on a file system that does not require normalization
  163          * or case folding.  We can also look there if we happen to be
  164          * on a non-normalizing, mixed sensitivity file system IF we
  165          * are looking for the exact name.
  166          *
  167          * NB: we do not need to worry about this flag for ZFS_CASE_SENSITIVE
  168          * because in that case MT_EXACT and MT_FIRST should produce exactly
  169          * the same result.
  170          */
  171 
  172         if (dzp->z_unlinked && !(flag & ZXATTR))
  173                 return (ENOENT);
  174         if (flag & ZXATTR) {
  175                 error = sa_lookup(dzp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs), &zoid,
  176                     sizeof (zoid));
  177                 if (error == 0)
  178                         error = (zoid == 0 ? ENOENT : 0);
  179         } else {
  180                 error = zfs_match_find(zfsvfs, dzp, name, mt, &zoid);
  181         }
  182         if (error) {
  183                 if (error != ENOENT || (flag & ZEXISTS)) {
  184                         return (error);
  185                 }
  186         } else {
  187                 if (flag & ZNEW) {
  188                         return (SET_ERROR(EEXIST));
  189                 }
  190                 error = zfs_zget(zfsvfs, zoid, &zp);
  191                 if (error)
  192                         return (error);
  193                 ASSERT(!zp->z_unlinked);
  194                 *zpp = zp;
  195         }
  196 
  197         return (0);
  198 }
  199 
  200 static int
  201 zfs_dd_lookup(znode_t *dzp, znode_t **zpp)
  202 {
  203         zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
  204         znode_t *zp;
  205         uint64_t parent;
  206         int error;
  207 
  208 #ifdef ZFS_DEBUG
  209         if (zfsvfs->z_replay == B_FALSE)
  210                 ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  211 #endif
  212         if (dzp->z_unlinked)
  213                 return (ENOENT);
  214 
  215         if ((error = sa_lookup(dzp->z_sa_hdl,
  216             SA_ZPL_PARENT(zfsvfs), &parent, sizeof (parent))) != 0)
  217                 return (error);
  218 
  219         error = zfs_zget(zfsvfs, parent, &zp);
  220         if (error == 0)
  221                 *zpp = zp;
  222         return (error);
  223 }
  224 
  225 int
  226 zfs_dirlook(znode_t *dzp, const char *name, znode_t **zpp)
  227 {
  228         zfsvfs_t *zfsvfs __unused = dzp->z_zfsvfs;
  229         znode_t *zp = NULL;
  230         int error = 0;
  231 
  232 #ifdef ZFS_DEBUG
  233         if (zfsvfs->z_replay == B_FALSE)
  234                 ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  235 #endif
  236         if (dzp->z_unlinked)
  237                 return (SET_ERROR(ENOENT));
  238 
  239         if (name[0] == 0 || (name[0] == '.' && name[1] == 0)) {
  240                 *zpp = dzp;
  241         } else if (name[0] == '.' && name[1] == '.' && name[2] == 0) {
  242                 error = zfs_dd_lookup(dzp, &zp);
  243                 if (error == 0)
  244                         *zpp = zp;
  245         } else {
  246                 error = zfs_dirent_lookup(dzp, name, &zp, ZEXISTS);
  247                 if (error == 0) {
  248                         dzp->z_zn_prefetch = B_TRUE; /* enable prefetching */
  249                         *zpp = zp;
  250                 }
  251         }
  252         return (error);
  253 }
  254 
  255 /*
  256  * unlinked Set (formerly known as the "delete queue") Error Handling
  257  *
  258  * When dealing with the unlinked set, we dmu_tx_hold_zap(), but we
  259  * don't specify the name of the entry that we will be manipulating.  We
  260  * also fib and say that we won't be adding any new entries to the
  261  * unlinked set, even though we might (this is to lower the minimum file
  262  * size that can be deleted in a full filesystem).  So on the small
  263  * chance that the nlink list is using a fat zap (ie. has more than
  264  * 2000 entries), we *may* not pre-read a block that's needed.
  265  * Therefore it is remotely possible for some of the assertions
  266  * regarding the unlinked set below to fail due to i/o error.  On a
  267  * nondebug system, this will result in the space being leaked.
  268  */
  269 void
  270 zfs_unlinked_add(znode_t *zp, dmu_tx_t *tx)
  271 {
  272         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  273 
  274         ASSERT(zp->z_unlinked);
  275         ASSERT3U(zp->z_links, ==, 0);
  276 
  277         VERIFY0(zap_add_int(zfsvfs->z_os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
  278 
  279         dataset_kstats_update_nunlinks_kstat(&zfsvfs->z_kstat, 1);
  280 }
  281 
  282 /*
  283  * Clean up any znodes that had no links when we either crashed or
  284  * (force) umounted the file system.
  285  */
  286 void
  287 zfs_unlinked_drain(zfsvfs_t *zfsvfs)
  288 {
  289         zap_cursor_t    zc;
  290         zap_attribute_t zap;
  291         dmu_object_info_t doi;
  292         znode_t         *zp;
  293         dmu_tx_t        *tx;
  294         int             error;
  295 
  296         /*
  297          * Iterate over the contents of the unlinked set.
  298          */
  299         for (zap_cursor_init(&zc, zfsvfs->z_os, zfsvfs->z_unlinkedobj);
  300             zap_cursor_retrieve(&zc, &zap) == 0;
  301             zap_cursor_advance(&zc)) {
  302 
  303                 /*
  304                  * See what kind of object we have in list
  305                  */
  306 
  307                 error = dmu_object_info(zfsvfs->z_os,
  308                     zap.za_first_integer, &doi);
  309                 if (error != 0)
  310                         continue;
  311 
  312                 ASSERT((doi.doi_type == DMU_OT_PLAIN_FILE_CONTENTS) ||
  313                     (doi.doi_type == DMU_OT_DIRECTORY_CONTENTS));
  314                 /*
  315                  * We need to re-mark these list entries for deletion,
  316                  * so we pull them back into core and set zp->z_unlinked.
  317                  */
  318                 error = zfs_zget(zfsvfs, zap.za_first_integer, &zp);
  319 
  320                 /*
  321                  * We may pick up znodes that are already marked for deletion.
  322                  * This could happen during the purge of an extended attribute
  323                  * directory.  All we need to do is skip over them, since they
  324                  * are already in the system marked z_unlinked.
  325                  */
  326                 if (error != 0)
  327                         continue;
  328 
  329                 vn_lock(ZTOV(zp), LK_EXCLUSIVE | LK_RETRY);
  330 
  331                 /*
  332                  * Due to changes in zfs_rmnode we need to make sure the
  333                  * link count is set to zero here.
  334                  */
  335                 if (zp->z_links != 0) {
  336                         tx = dmu_tx_create(zfsvfs->z_os);
  337                         dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
  338                         error = dmu_tx_assign(tx, TXG_WAIT);
  339                         if (error != 0) {
  340                                 dmu_tx_abort(tx);
  341                                 vput(ZTOV(zp));
  342                                 continue;
  343                         }
  344                         zp->z_links = 0;
  345                         VERIFY0(sa_update(zp->z_sa_hdl, SA_ZPL_LINKS(zfsvfs),
  346                             &zp->z_links, sizeof (zp->z_links), tx));
  347                         dmu_tx_commit(tx);
  348                 }
  349 
  350                 zp->z_unlinked = B_TRUE;
  351                 vput(ZTOV(zp));
  352         }
  353         zap_cursor_fini(&zc);
  354 }
  355 
  356 /*
  357  * Delete the entire contents of a directory.  Return a count
  358  * of the number of entries that could not be deleted. If we encounter
  359  * an error, return a count of at least one so that the directory stays
  360  * in the unlinked set.
  361  *
  362  * NOTE: this function assumes that the directory is inactive,
  363  *      so there is no need to lock its entries before deletion.
  364  *      Also, it assumes the directory contents is *only* regular
  365  *      files.
  366  */
  367 static int
  368 zfs_purgedir(znode_t *dzp)
  369 {
  370         zap_cursor_t    zc;
  371         zap_attribute_t zap;
  372         znode_t         *xzp;
  373         dmu_tx_t        *tx;
  374         zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
  375         int skipped = 0;
  376         int error;
  377 
  378         for (zap_cursor_init(&zc, zfsvfs->z_os, dzp->z_id);
  379             (error = zap_cursor_retrieve(&zc, &zap)) == 0;
  380             zap_cursor_advance(&zc)) {
  381                 error = zfs_zget(zfsvfs,
  382                     ZFS_DIRENT_OBJ(zap.za_first_integer), &xzp);
  383                 if (error) {
  384                         skipped += 1;
  385                         continue;
  386                 }
  387 
  388                 vn_lock(ZTOV(xzp), LK_EXCLUSIVE | LK_RETRY);
  389                 ASSERT((ZTOV(xzp)->v_type == VREG) ||
  390                     (ZTOV(xzp)->v_type == VLNK));
  391 
  392                 tx = dmu_tx_create(zfsvfs->z_os);
  393                 dmu_tx_hold_sa(tx, dzp->z_sa_hdl, B_FALSE);
  394                 dmu_tx_hold_zap(tx, dzp->z_id, FALSE, zap.za_name);
  395                 dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
  396                 dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
  397                 /* Is this really needed ? */
  398                 zfs_sa_upgrade_txholds(tx, xzp);
  399                 dmu_tx_mark_netfree(tx);
  400                 error = dmu_tx_assign(tx, TXG_WAIT);
  401                 if (error) {
  402                         dmu_tx_abort(tx);
  403                         vput(ZTOV(xzp));
  404                         skipped += 1;
  405                         continue;
  406                 }
  407 
  408                 error = zfs_link_destroy(dzp, zap.za_name, xzp, tx, 0, NULL);
  409                 if (error)
  410                         skipped += 1;
  411                 dmu_tx_commit(tx);
  412 
  413                 vput(ZTOV(xzp));
  414         }
  415         zap_cursor_fini(&zc);
  416         if (error != ENOENT)
  417                 skipped += 1;
  418         return (skipped);
  419 }
  420 
  421 extern taskq_t *zfsvfs_taskq;
  422 
  423 void
  424 zfs_rmnode(znode_t *zp)
  425 {
  426         zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
  427         objset_t        *os = zfsvfs->z_os;
  428         dmu_tx_t        *tx;
  429         uint64_t        z_id = zp->z_id;
  430         uint64_t        acl_obj;
  431         uint64_t        xattr_obj;
  432         uint64_t        count;
  433         int             error;
  434 
  435         ASSERT3U(zp->z_links, ==, 0);
  436         if (zfsvfs->z_replay == B_FALSE)
  437                 ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  438 
  439         /*
  440          * If this is an attribute directory, purge its contents.
  441          */
  442         if (ZTOV(zp) != NULL && ZTOV(zp)->v_type == VDIR &&
  443             (zp->z_pflags & ZFS_XATTR)) {
  444                 if (zfs_purgedir(zp) != 0) {
  445                         /*
  446                          * Not enough space to delete some xattrs.
  447                          * Leave it in the unlinked set.
  448                          */
  449                         ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
  450                         zfs_znode_dmu_fini(zp);
  451                         zfs_znode_free(zp);
  452                         ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
  453                         return;
  454                 }
  455         } else {
  456                 /*
  457                  * Free up all the data in the file.  We don't do this for
  458                  * XATTR directories because we need truncate and remove to be
  459                  * in the same tx, like in zfs_znode_delete(). Otherwise, if
  460                  * we crash here we'll end up with an inconsistent truncated
  461                  * zap object in the delete queue.  Note a truncated file is
  462                  * harmless since it only contains user data.
  463                  */
  464                 error = dmu_free_long_range(os, zp->z_id, 0, DMU_OBJECT_END);
  465                 if (error) {
  466                         /*
  467                          * Not enough space or we were interrupted by unmount.
  468                          * Leave the file in the unlinked set.
  469                          */
  470                         ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
  471                         zfs_znode_dmu_fini(zp);
  472                         zfs_znode_free(zp);
  473                         ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
  474                         return;
  475                 }
  476         }
  477 
  478         /*
  479          * If the file has extended attributes, we're going to unlink
  480          * the xattr dir.
  481          */
  482         error = sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs),
  483             &xattr_obj, sizeof (xattr_obj));
  484         if (error)
  485                 xattr_obj = 0;
  486 
  487         acl_obj = zfs_external_acl(zp);
  488 
  489         /*
  490          * Set up the final transaction.
  491          */
  492         tx = dmu_tx_create(os);
  493         dmu_tx_hold_free(tx, zp->z_id, 0, DMU_OBJECT_END);
  494         dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
  495         if (xattr_obj)
  496                 dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, TRUE, NULL);
  497         if (acl_obj)
  498                 dmu_tx_hold_free(tx, acl_obj, 0, DMU_OBJECT_END);
  499 
  500         zfs_sa_upgrade_txholds(tx, zp);
  501         error = dmu_tx_assign(tx, TXG_WAIT);
  502         if (error) {
  503                 /*
  504                  * Not enough space to delete the file.  Leave it in the
  505                  * unlinked set, leaking it until the fs is remounted (at
  506                  * which point we'll call zfs_unlinked_drain() to process it).
  507                  */
  508                 dmu_tx_abort(tx);
  509                 ZFS_OBJ_HOLD_ENTER(zfsvfs, z_id);
  510                 zfs_znode_dmu_fini(zp);
  511                 zfs_znode_free(zp);
  512                 ZFS_OBJ_HOLD_EXIT(zfsvfs, z_id);
  513                 return;
  514         }
  515 
  516         /*
  517          * FreeBSD's implementation of zfs_zget requires a vnode to back it.
  518          * This means that we could end up calling into getnewvnode while
  519          * calling zfs_rmnode as a result of a prior call to getnewvnode
  520          * trying to clear vnodes out of the cache. If this repeats we can
  521          * recurse enough that we overflow our stack. To avoid this, we
  522          * avoid calling zfs_zget on the xattr znode and instead simply add
  523          * it to the unlinked set and schedule a call to zfs_unlinked_drain.
  524          */
  525         if (xattr_obj) {
  526                 /* Add extended attribute directory to the unlinked set. */
  527                 VERIFY3U(0, ==,
  528                     zap_add_int(os, zfsvfs->z_unlinkedobj, xattr_obj, tx));
  529         }
  530 
  531         mutex_enter(&os->os_dsl_dataset->ds_dir->dd_activity_lock);
  532 
  533         /* Remove this znode from the unlinked set */
  534         VERIFY3U(0, ==,
  535             zap_remove_int(os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
  536 
  537         if (zap_count(os, zfsvfs->z_unlinkedobj, &count) == 0 && count == 0) {
  538                 cv_broadcast(&os->os_dsl_dataset->ds_dir->dd_activity_cv);
  539         }
  540 
  541         mutex_exit(&os->os_dsl_dataset->ds_dir->dd_activity_lock);
  542 
  543         dataset_kstats_update_nunlinked_kstat(&zfsvfs->z_kstat, 1);
  544 
  545         zfs_znode_delete(zp, tx);
  546 
  547         dmu_tx_commit(tx);
  548 
  549         if (xattr_obj) {
  550                 /*
  551                  * We're using the FreeBSD taskqueue API here instead of
  552                  * the Solaris taskq API since the FreeBSD API allows for a
  553                  * task to be enqueued multiple times but executed once.
  554                  */
  555                 taskqueue_enqueue(zfsvfs_taskq->tq_queue,
  556                     &zfsvfs->z_unlinked_drain_task);
  557         }
  558 }
  559 
  560 static uint64_t
  561 zfs_dirent(znode_t *zp, uint64_t mode)
  562 {
  563         uint64_t de = zp->z_id;
  564 
  565         if (zp->z_zfsvfs->z_version >= ZPL_VERSION_DIRENT_TYPE)
  566                 de |= IFTODT(mode) << 60;
  567         return (de);
  568 }
  569 
  570 /*
  571  * Link zp into dzp.  Can only fail if zp has been unlinked.
  572  */
  573 int
  574 zfs_link_create(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  575     int flag)
  576 {
  577         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  578         vnode_t *vp = ZTOV(zp);
  579         uint64_t value;
  580         int zp_is_dir = (vp->v_type == VDIR);
  581         sa_bulk_attr_t bulk[5];
  582         uint64_t mtime[2], ctime[2];
  583         int count = 0;
  584         int error;
  585 
  586         if (zfsvfs->z_replay == B_FALSE) {
  587                 ASSERT_VOP_ELOCKED(ZTOV(dzp), __func__);
  588                 ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  589         }
  590         if (zp_is_dir) {
  591                 if (dzp->z_links >= ZFS_LINK_MAX)
  592                         return (SET_ERROR(EMLINK));
  593         }
  594         if (!(flag & ZRENAMING)) {
  595                 if (zp->z_unlinked) {   /* no new links to unlinked zp */
  596                         ASSERT(!(flag & (ZNEW | ZEXISTS)));
  597                         return (SET_ERROR(ENOENT));
  598                 }
  599                 if (zp->z_links >= ZFS_LINK_MAX - zp_is_dir) {
  600                         return (SET_ERROR(EMLINK));
  601                 }
  602                 zp->z_links++;
  603                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs), NULL,
  604                     &zp->z_links, sizeof (zp->z_links));
  605 
  606         } else {
  607                 ASSERT(!zp->z_unlinked);
  608         }
  609         value = zfs_dirent(zp, zp->z_mode);
  610         error = zap_add(zp->z_zfsvfs->z_os, dzp->z_id, name,
  611             8, 1, &value, tx);
  612 
  613         /*
  614          * zap_add could fail to add the entry if it exceeds the capacity of the
  615          * leaf-block and zap_leaf_split() failed to help.
  616          * The caller of this routine is responsible for failing the transaction
  617          * which will rollback the SA updates done above.
  618          */
  619         if (error != 0) {
  620                 if (!(flag & ZRENAMING) && !(flag & ZNEW))
  621                         zp->z_links--;
  622                 return (error);
  623         }
  624 
  625         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zfsvfs), NULL,
  626             &dzp->z_id, sizeof (dzp->z_id));
  627         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
  628             &zp->z_pflags, sizeof (zp->z_pflags));
  629 
  630         if (!(flag & ZNEW)) {
  631                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
  632                     ctime, sizeof (ctime));
  633                 zfs_tstamp_update_setup(zp, STATE_CHANGED, mtime,
  634                     ctime);
  635         }
  636         error = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
  637         ASSERT0(error);
  638 
  639         dzp->z_size++;
  640         dzp->z_links += zp_is_dir;
  641         count = 0;
  642         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs), NULL,
  643             &dzp->z_size, sizeof (dzp->z_size));
  644         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs), NULL,
  645             &dzp->z_links, sizeof (dzp->z_links));
  646         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL,
  647             mtime, sizeof (mtime));
  648         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
  649             ctime, sizeof (ctime));
  650         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
  651             &dzp->z_pflags, sizeof (dzp->z_pflags));
  652         zfs_tstamp_update_setup(dzp, CONTENT_MODIFIED, mtime, ctime);
  653         error = sa_bulk_update(dzp->z_sa_hdl, bulk, count, tx);
  654         ASSERT0(error);
  655         return (0);
  656 }
  657 
  658 /*
  659  * The match type in the code for this function should conform to:
  660  *
  661  * ------------------------------------------------------------------------
  662  * fs type  | z_norm      | lookup type | match type
  663  * ---------|-------------|-------------|----------------------------------
  664  * CS !norm | 0           |           0 | 0 (exact)
  665  * CS  norm | formX       |           0 | MT_NORMALIZE
  666  * CI !norm | upper       |   !ZCIEXACT | MT_NORMALIZE
  667  * CI !norm | upper       |    ZCIEXACT | MT_NORMALIZE | MT_MATCH_CASE
  668  * CI  norm | upper|formX |   !ZCIEXACT | MT_NORMALIZE
  669  * CI  norm | upper|formX |    ZCIEXACT | MT_NORMALIZE | MT_MATCH_CASE
  670  * CM !norm | upper       |    !ZCILOOK | MT_NORMALIZE | MT_MATCH_CASE
  671  * CM !norm | upper       |     ZCILOOK | MT_NORMALIZE
  672  * CM  norm | upper|formX |    !ZCILOOK | MT_NORMALIZE | MT_MATCH_CASE
  673  * CM  norm | upper|formX |     ZCILOOK | MT_NORMALIZE
  674  *
  675  * Abbreviations:
  676  *    CS = Case Sensitive, CI = Case Insensitive, CM = Case Mixed
  677  *    upper = case folding set by fs type on creation (U8_TEXTPREP_TOUPPER)
  678  *    formX = unicode normalization form set on fs creation
  679  */
  680 static int
  681 zfs_dropname(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  682     int flag)
  683 {
  684         int error;
  685 
  686         if (zp->z_zfsvfs->z_norm) {
  687                 matchtype_t mt = MT_NORMALIZE;
  688 
  689                 if (zp->z_zfsvfs->z_case == ZFS_CASE_MIXED) {
  690                         mt |= MT_MATCH_CASE;
  691                 }
  692 
  693                 error = zap_remove_norm(zp->z_zfsvfs->z_os, dzp->z_id,
  694                     name, mt, tx);
  695         } else {
  696                 error = zap_remove(zp->z_zfsvfs->z_os, dzp->z_id, name, tx);
  697         }
  698 
  699         return (error);
  700 }
  701 
  702 /*
  703  * Unlink zp from dzp, and mark zp for deletion if this was the last link.
  704  * Can fail if zp is a mount point (EBUSY) or a non-empty directory (EEXIST).
  705  * If 'unlinkedp' is NULL, we put unlinked znodes on the unlinked list.
  706  * If it's non-NULL, we use it to indicate whether the znode needs deletion,
  707  * and it's the caller's job to do it.
  708  */
  709 int
  710 zfs_link_destroy(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  711     int flag, boolean_t *unlinkedp)
  712 {
  713         zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
  714         vnode_t *vp = ZTOV(zp);
  715         int zp_is_dir = (vp->v_type == VDIR);
  716         boolean_t unlinked = B_FALSE;
  717         sa_bulk_attr_t bulk[5];
  718         uint64_t mtime[2], ctime[2];
  719         int count = 0;
  720         int error;
  721 
  722         if (zfsvfs->z_replay == B_FALSE) {
  723                 ASSERT_VOP_ELOCKED(ZTOV(dzp), __func__);
  724                 ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  725         }
  726         if (!(flag & ZRENAMING)) {
  727 
  728                 if (zp_is_dir && !zfs_dirempty(zp))
  729                         return (SET_ERROR(ENOTEMPTY));
  730 
  731                 /*
  732                  * If we get here, we are going to try to remove the object.
  733                  * First try removing the name from the directory; if that
  734                  * fails, return the error.
  735                  */
  736                 error = zfs_dropname(dzp, name, zp, tx, flag);
  737                 if (error != 0) {
  738                         return (error);
  739                 }
  740 
  741                 if (zp->z_links <= zp_is_dir) {
  742                         zfs_panic_recover("zfs: link count on vnode %p is %u, "
  743                             "should be at least %u", zp->z_vnode,
  744                             (int)zp->z_links,
  745                             zp_is_dir + 1);
  746                         zp->z_links = zp_is_dir + 1;
  747                 }
  748                 if (--zp->z_links == zp_is_dir) {
  749                         zp->z_unlinked = B_TRUE;
  750                         zp->z_links = 0;
  751                         unlinked = B_TRUE;
  752                 } else {
  753                         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs),
  754                             NULL, &ctime, sizeof (ctime));
  755                         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs),
  756                             NULL, &zp->z_pflags, sizeof (zp->z_pflags));
  757                         zfs_tstamp_update_setup(zp, STATE_CHANGED, mtime,
  758                             ctime);
  759                 }
  760                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs),
  761                     NULL, &zp->z_links, sizeof (zp->z_links));
  762                 error = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
  763                 count = 0;
  764                 ASSERT0(error);
  765         } else {
  766                 ASSERT(!zp->z_unlinked);
  767                 error = zfs_dropname(dzp, name, zp, tx, flag);
  768                 if (error != 0)
  769                         return (error);
  770         }
  771 
  772         dzp->z_size--;          /* one dirent removed */
  773         dzp->z_links -= zp_is_dir;      /* ".." link from zp */
  774         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs),
  775             NULL, &dzp->z_links, sizeof (dzp->z_links));
  776         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs),
  777             NULL, &dzp->z_size, sizeof (dzp->z_size));
  778         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs),
  779             NULL, ctime, sizeof (ctime));
  780         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs),
  781             NULL, mtime, sizeof (mtime));
  782         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs),
  783             NULL, &dzp->z_pflags, sizeof (dzp->z_pflags));
  784         zfs_tstamp_update_setup(dzp, CONTENT_MODIFIED, mtime, ctime);
  785         error = sa_bulk_update(dzp->z_sa_hdl, bulk, count, tx);
  786         ASSERT0(error);
  787 
  788         if (unlinkedp != NULL)
  789                 *unlinkedp = unlinked;
  790         else if (unlinked)
  791                 zfs_unlinked_add(zp, tx);
  792 
  793         return (0);
  794 }
  795 
  796 /*
  797  * Indicate whether the directory is empty.
  798  */
  799 boolean_t
  800 zfs_dirempty(znode_t *dzp)
  801 {
  802         return (dzp->z_size == 2);
  803 }
  804 
  805 int
  806 zfs_make_xattrdir(znode_t *zp, vattr_t *vap, znode_t **xvpp, cred_t *cr)
  807 {
  808         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  809         znode_t *xzp;
  810         dmu_tx_t *tx;
  811         int error;
  812         zfs_acl_ids_t acl_ids;
  813         boolean_t fuid_dirtied;
  814         uint64_t parent __maybe_unused;
  815 
  816         *xvpp = NULL;
  817 
  818         if ((error = zfs_acl_ids_create(zp, IS_XATTR, vap, cr, NULL,
  819             &acl_ids, NULL)) != 0)
  820                 return (error);
  821         if (zfs_acl_ids_overquota(zfsvfs, &acl_ids, 0)) {
  822                 zfs_acl_ids_free(&acl_ids);
  823                 return (SET_ERROR(EDQUOT));
  824         }
  825 
  826         getnewvnode_reserve_();
  827 
  828         tx = dmu_tx_create(zfsvfs->z_os);
  829         dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
  830             ZFS_SA_BASE_ATTR_SIZE);
  831         dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
  832         dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
  833         fuid_dirtied = zfsvfs->z_fuid_dirty;
  834         if (fuid_dirtied)
  835                 zfs_fuid_txhold(zfsvfs, tx);
  836         error = dmu_tx_assign(tx, TXG_WAIT);
  837         if (error) {
  838                 zfs_acl_ids_free(&acl_ids);
  839                 dmu_tx_abort(tx);
  840                 getnewvnode_drop_reserve();
  841                 return (error);
  842         }
  843         zfs_mknode(zp, vap, tx, cr, IS_XATTR, &xzp, &acl_ids);
  844 
  845         if (fuid_dirtied)
  846                 zfs_fuid_sync(zfsvfs, tx);
  847 
  848         ASSERT0(sa_lookup(xzp->z_sa_hdl, SA_ZPL_PARENT(zfsvfs), &parent,
  849             sizeof (parent)));
  850         ASSERT3U(parent, ==, zp->z_id);
  851 
  852         VERIFY0(sa_update(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs), &xzp->z_id,
  853             sizeof (xzp->z_id), tx));
  854 
  855         zfs_log_create(zfsvfs->z_log, tx, TX_MKXATTR, zp, xzp, "", NULL,
  856             acl_ids.z_fuidp, vap);
  857 
  858         zfs_acl_ids_free(&acl_ids);
  859         dmu_tx_commit(tx);
  860 
  861         getnewvnode_drop_reserve();
  862 
  863         *xvpp = xzp;
  864 
  865         return (0);
  866 }
  867 
  868 /*
  869  * Return a znode for the extended attribute directory for zp.
  870  * ** If the directory does not already exist, it is created **
  871  *
  872  *      IN:     zp      - znode to obtain attribute directory from
  873  *              cr      - credentials of caller
  874  *              flags   - flags from the VOP_LOOKUP call
  875  *
  876  *      OUT:    xzpp    - pointer to extended attribute znode
  877  *
  878  *      RETURN: 0 on success
  879  *              error number on failure
  880  */
  881 int
  882 zfs_get_xattrdir(znode_t *zp, znode_t **xzpp, cred_t *cr, int flags)
  883 {
  884         zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
  885         znode_t         *xzp;
  886         vattr_t         va;
  887         int             error;
  888 top:
  889         error = zfs_dirent_lookup(zp, "", &xzp, ZXATTR);
  890         if (error)
  891                 return (error);
  892 
  893         if (xzp != NULL) {
  894                 *xzpp = xzp;
  895                 return (0);
  896         }
  897 
  898 
  899         if (!(flags & CREATE_XATTR_DIR))
  900                 return (SET_ERROR(ENOATTR));
  901 
  902         if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) {
  903                 return (SET_ERROR(EROFS));
  904         }
  905 
  906         /*
  907          * The ability to 'create' files in an attribute
  908          * directory comes from the write_xattr permission on the base file.
  909          *
  910          * The ability to 'search' an attribute directory requires
  911          * read_xattr permission on the base file.
  912          *
  913          * Once in a directory the ability to read/write attributes
  914          * is controlled by the permissions on the attribute file.
  915          */
  916         va.va_mask = AT_MODE | AT_UID | AT_GID;
  917         va.va_type = VDIR;
  918         va.va_mode = S_IFDIR | S_ISVTX | 0777;
  919         zfs_fuid_map_ids(zp, cr, &va.va_uid, &va.va_gid);
  920 
  921         error = zfs_make_xattrdir(zp, &va, xzpp, cr);
  922 
  923         if (error == ERESTART) {
  924                 /* NB: we already did dmu_tx_wait() if necessary */
  925                 goto top;
  926         }
  927         if (error == 0)
  928                 VOP_UNLOCK1(ZTOV(*xzpp));
  929 
  930         return (error);
  931 }
  932 
  933 /*
  934  * Decide whether it is okay to remove within a sticky directory.
  935  *
  936  * In sticky directories, write access is not sufficient;
  937  * you can remove entries from a directory only if:
  938  *
  939  *      you own the directory,
  940  *      you own the entry,
  941  *      the entry is a plain file and you have write access,
  942  *      or you are privileged (checked in secpolicy...).
  943  *
  944  * The function returns 0 if remove access is granted.
  945  */
  946 int
  947 zfs_sticky_remove_access(znode_t *zdp, znode_t *zp, cred_t *cr)
  948 {
  949         uid_t           uid;
  950         uid_t           downer;
  951         uid_t           fowner;
  952         zfsvfs_t        *zfsvfs = zdp->z_zfsvfs;
  953 
  954         if (zdp->z_zfsvfs->z_replay)
  955                 return (0);
  956 
  957         if ((zdp->z_mode & S_ISVTX) == 0)
  958                 return (0);
  959 
  960         downer = zfs_fuid_map_id(zfsvfs, zdp->z_uid, cr, ZFS_OWNER);
  961         fowner = zfs_fuid_map_id(zfsvfs, zp->z_uid, cr, ZFS_OWNER);
  962 
  963         if ((uid = crgetuid(cr)) == downer || uid == fowner ||
  964             (ZTOV(zp)->v_type == VREG &&
  965             zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr, NULL) == 0))
  966                 return (0);
  967         else
  968                 return (secpolicy_vnode_remove(ZTOV(zp), cr));
  969 }

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