The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/cddl/contrib/opensolaris/uts/common/fs/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 http://www.opensolaris.org/os/licensing.
   10  * See the License for the specific language governing permissions
   11  * and limitations under the License.
   12  *
   13  * When distributing Covered Code, include this CDDL HEADER in each
   14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
   15  * If applicable, add the following below this CDDL HEADER, with the
   16  * fields enclosed by brackets "[]" replaced with your own identifying
   17  * information: Portions Copyright [yyyy] [name of copyright owner]
   18  *
   19  * CDDL HEADER END
   20  */
   21 /*
   22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   23  * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
   24  */
   25 
   26 #include <sys/types.h>
   27 #include <sys/param.h>
   28 #include <sys/time.h>
   29 #include <sys/systm.h>
   30 #include <sys/sysmacros.h>
   31 #include <sys/resource.h>
   32 #include <sys/vfs.h>
   33 #include <sys/vnode.h>
   34 #include <sys/file.h>
   35 #include <sys/kmem.h>
   36 #include <sys/uio.h>
   37 #include <sys/cmn_err.h>
   38 #include <sys/errno.h>
   39 #include <sys/stat.h>
   40 #include <sys/unistd.h>
   41 #include <sys/sunddi.h>
   42 #include <sys/random.h>
   43 #include <sys/policy.h>
   44 #include <sys/kcondvar.h>
   45 #include <sys/callb.h>
   46 #include <sys/smp.h>
   47 #include <sys/zfs_dir.h>
   48 #include <sys/zfs_acl.h>
   49 #include <sys/fs/zfs.h>
   50 #include <sys/zap.h>
   51 #include <sys/dmu.h>
   52 #include <sys/atomic.h>
   53 #include <sys/zfs_ctldir.h>
   54 #include <sys/zfs_fuid.h>
   55 #include <sys/sa.h>
   56 #include <sys/zfs_sa.h>
   57 #include <sys/dnlc.h>
   58 #include <sys/extdirent.h>
   59 
   60 /*
   61  * zfs_match_find() is used by zfs_dirent_lookup() to peform zap lookups
   62  * of names after deciding which is the appropriate lookup interface.
   63  */
   64 static int
   65 zfs_match_find(zfsvfs_t *zfsvfs, znode_t *dzp, const char *name,
   66     boolean_t exact, uint64_t *zoid)
   67 {
   68         int error;
   69 
   70         if (zfsvfs->z_norm) {
   71                 matchtype_t mt = exact? MT_EXACT : MT_FIRST;
   72 
   73                 /*
   74                  * In the non-mixed case we only expect there would ever
   75                  * be one match, but we need to use the normalizing lookup.
   76                  */
   77                 error = zap_lookup_norm(zfsvfs->z_os, dzp->z_id, name, 8, 1,
   78                     zoid, mt, NULL, 0, NULL);
   79         } else {
   80                 error = zap_lookup(zfsvfs->z_os, dzp->z_id, name, 8, 1, zoid);
   81         }
   82         *zoid = ZFS_DIRENT_OBJ(*zoid);
   83 
   84         return (error);
   85 }
   86 
   87 /*
   88  * Look up a directory entry under a locked vnode.
   89  * dvp being locked gives us a guarantee that there are no concurrent
   90  * modification of the directory and, thus, if a node can be found in
   91  * the directory, then it must not be unlinked.
   92  *
   93  * Input arguments:
   94  *      dzp     - znode for directory
   95  *      name    - name of entry to lock
   96  *      flag    - ZNEW: if the entry already exists, fail with EEXIST.
   97  *                ZEXISTS: if the entry does not exist, fail with ENOENT.
   98  *                ZXATTR: we want dzp's xattr directory
   99  *
  100  * Output arguments:
  101  *      zpp     - pointer to the znode for the entry (NULL if there isn't one)
  102  *
  103  * Return value: 0 on success or errno on failure.
  104  *
  105  * NOTE: Always checks for, and rejects, '.' and '..'.
  106  */
  107 int
  108 zfs_dirent_lookup(znode_t *dzp, const char *name, znode_t **zpp, int flag)
  109 {
  110         zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
  111         boolean_t       exact;
  112         uint64_t        zoid;
  113         vnode_t         *vp = NULL;
  114         int             error = 0;
  115 
  116         ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  117 
  118         *zpp = NULL;
  119 
  120         /*
  121          * Verify that we are not trying to lock '.', '..', or '.zfs'
  122          */
  123         if (name[0] == '.' &&
  124             (name[1] == '\0' || (name[1] == '.' && name[2] == '\0')) ||
  125             zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0)
  126                 return (SET_ERROR(EEXIST));
  127 
  128         /*
  129          * Case sensitivity and normalization preferences are set when
  130          * the file system is created.  These are stored in the
  131          * zfsvfs->z_case and zfsvfs->z_norm fields.  These choices
  132          * affect how we perform zap lookups.
  133          *
  134          * Decide if exact matches should be requested when performing
  135          * a zap lookup on file systems supporting case-insensitive
  136          * access.
  137          *
  138          * NB: we do not need to worry about this flag for ZFS_CASE_SENSITIVE
  139          * because in that case MT_EXACT and MT_FIRST should produce exactly
  140          * the same result.
  141          */
  142         exact = zfsvfs->z_case == ZFS_CASE_MIXED;
  143 
  144         if (dzp->z_unlinked && !(flag & ZXATTR))
  145                 return (ENOENT);
  146         if (flag & ZXATTR) {
  147                 error = sa_lookup(dzp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs), &zoid,
  148                     sizeof (zoid));
  149                 if (error == 0)
  150                         error = (zoid == 0 ? ENOENT : 0);
  151         } else {
  152                 error = zfs_match_find(zfsvfs, dzp, name, exact, &zoid);
  153         }
  154         if (error) {
  155                 if (error != ENOENT || (flag & ZEXISTS)) {
  156                         return (error);
  157                 }
  158         } else {
  159                 if (flag & ZNEW) {
  160                         return (SET_ERROR(EEXIST));
  161                 }
  162                 error = zfs_zget(zfsvfs, zoid, zpp);
  163                 if (error)
  164                         return (error);
  165                 ASSERT(!(*zpp)->z_unlinked);
  166         }
  167 
  168         return (0);
  169 }
  170 
  171 static int
  172 zfs_dd_lookup(znode_t *dzp, znode_t **zpp)
  173 {
  174         zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
  175         znode_t *zp;
  176         uint64_t parent;
  177         int error;
  178 
  179         ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  180         ASSERT(RRM_READ_HELD(&zfsvfs->z_teardown_lock));
  181 
  182         if (dzp->z_unlinked)
  183                 return (ENOENT);
  184 
  185         if ((error = sa_lookup(dzp->z_sa_hdl,
  186             SA_ZPL_PARENT(zfsvfs), &parent, sizeof (parent))) != 0)
  187                 return (error);
  188 
  189         error = zfs_zget(zfsvfs, parent, &zp);
  190         if (error == 0)
  191                 *zpp = zp;
  192         return (error);
  193 }
  194 
  195 int
  196 zfs_dirlook(znode_t *dzp, const char *name, znode_t **zpp)
  197 {
  198         zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
  199         znode_t *zp;
  200         int error = 0;
  201 
  202         ASSERT_VOP_LOCKED(ZTOV(dzp), __func__);
  203         ASSERT(RRM_READ_HELD(&zfsvfs->z_teardown_lock));
  204 
  205         if (dzp->z_unlinked)
  206                 return (SET_ERROR(ENOENT));
  207 
  208         if (name[0] == 0 || (name[0] == '.' && name[1] == 0)) {
  209                 *zpp = dzp;
  210         } else if (name[0] == '.' && name[1] == '.' && name[2] == 0) {
  211                 error = zfs_dd_lookup(dzp, zpp);
  212         } else {
  213                 error = zfs_dirent_lookup(dzp, name, &zp, ZEXISTS);
  214                 if (error == 0) {
  215                         dzp->z_zn_prefetch = B_TRUE; /* enable prefetching */
  216                         *zpp = zp;
  217                 }
  218         }
  219         return (error);
  220 }
  221 
  222 /*
  223  * unlinked Set (formerly known as the "delete queue") Error Handling
  224  *
  225  * When dealing with the unlinked set, we dmu_tx_hold_zap(), but we
  226  * don't specify the name of the entry that we will be manipulating.  We
  227  * also fib and say that we won't be adding any new entries to the
  228  * unlinked set, even though we might (this is to lower the minimum file
  229  * size that can be deleted in a full filesystem).  So on the small
  230  * chance that the nlink list is using a fat zap (ie. has more than
  231  * 2000 entries), we *may* not pre-read a block that's needed.
  232  * Therefore it is remotely possible for some of the assertions
  233  * regarding the unlinked set below to fail due to i/o error.  On a
  234  * nondebug system, this will result in the space being leaked.
  235  */
  236 void
  237 zfs_unlinked_add(znode_t *zp, dmu_tx_t *tx)
  238 {
  239         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  240 
  241         ASSERT(zp->z_unlinked);
  242         ASSERT(zp->z_links == 0);
  243 
  244         VERIFY3U(0, ==,
  245             zap_add_int(zfsvfs->z_os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
  246 }
  247 
  248 /*
  249  * Clean up any znodes that had no links when we either crashed or
  250  * (force) umounted the file system.
  251  */
  252 void
  253 zfs_unlinked_drain(zfsvfs_t *zfsvfs)
  254 {
  255         zap_cursor_t    zc;
  256         zap_attribute_t zap;
  257         dmu_object_info_t doi;
  258         znode_t         *zp;
  259         int             error;
  260 
  261         /*
  262          * Interate over the contents of the unlinked set.
  263          */
  264         for (zap_cursor_init(&zc, zfsvfs->z_os, zfsvfs->z_unlinkedobj);
  265             zap_cursor_retrieve(&zc, &zap) == 0;
  266             zap_cursor_advance(&zc)) {
  267 
  268                 /*
  269                  * See what kind of object we have in list
  270                  */
  271 
  272                 error = dmu_object_info(zfsvfs->z_os,
  273                     zap.za_first_integer, &doi);
  274                 if (error != 0)
  275                         continue;
  276 
  277                 ASSERT((doi.doi_type == DMU_OT_PLAIN_FILE_CONTENTS) ||
  278                     (doi.doi_type == DMU_OT_DIRECTORY_CONTENTS));
  279                 /*
  280                  * We need to re-mark these list entries for deletion,
  281                  * so we pull them back into core and set zp->z_unlinked.
  282                  */
  283                 error = zfs_zget(zfsvfs, zap.za_first_integer, &zp);
  284 
  285                 /*
  286                  * We may pick up znodes that are already marked for deletion.
  287                  * This could happen during the purge of an extended attribute
  288                  * directory.  All we need to do is skip over them, since they
  289                  * are already in the system marked z_unlinked.
  290                  */
  291                 if (error != 0)
  292                         continue;
  293 
  294                 vn_lock(ZTOV(zp), LK_EXCLUSIVE | LK_RETRY);
  295                 zp->z_unlinked = B_TRUE;
  296                 vput(ZTOV(zp));
  297         }
  298         zap_cursor_fini(&zc);
  299 }
  300 
  301 /*
  302  * Delete the entire contents of a directory.  Return a count
  303  * of the number of entries that could not be deleted. If we encounter
  304  * an error, return a count of at least one so that the directory stays
  305  * in the unlinked set.
  306  *
  307  * NOTE: this function assumes that the directory is inactive,
  308  *      so there is no need to lock its entries before deletion.
  309  *      Also, it assumes the directory contents is *only* regular
  310  *      files.
  311  */
  312 static int
  313 zfs_purgedir(znode_t *dzp)
  314 {
  315         zap_cursor_t    zc;
  316         zap_attribute_t zap;
  317         znode_t         *xzp;
  318         dmu_tx_t        *tx;
  319         zfsvfs_t        *zfsvfs = dzp->z_zfsvfs;
  320         int skipped = 0;
  321         int error;
  322 
  323         for (zap_cursor_init(&zc, zfsvfs->z_os, dzp->z_id);
  324             (error = zap_cursor_retrieve(&zc, &zap)) == 0;
  325             zap_cursor_advance(&zc)) {
  326                 error = zfs_zget(zfsvfs,
  327                     ZFS_DIRENT_OBJ(zap.za_first_integer), &xzp);
  328                 if (error) {
  329                         skipped += 1;
  330                         continue;
  331                 }
  332 
  333                 vn_lock(ZTOV(xzp), LK_EXCLUSIVE | LK_RETRY);
  334                 ASSERT((ZTOV(xzp)->v_type == VREG) ||
  335                     (ZTOV(xzp)->v_type == VLNK));
  336 
  337                 tx = dmu_tx_create(zfsvfs->z_os);
  338                 dmu_tx_hold_sa(tx, dzp->z_sa_hdl, B_FALSE);
  339                 dmu_tx_hold_zap(tx, dzp->z_id, FALSE, zap.za_name);
  340                 dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
  341                 dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
  342                 /* Is this really needed ? */
  343                 zfs_sa_upgrade_txholds(tx, xzp);
  344                 dmu_tx_mark_netfree(tx);
  345                 error = dmu_tx_assign(tx, TXG_WAIT);
  346                 if (error) {
  347                         dmu_tx_abort(tx);
  348                         vput(ZTOV(xzp));
  349                         skipped += 1;
  350                         continue;
  351                 }
  352 
  353                 error = zfs_link_destroy(dzp, zap.za_name, xzp, tx, 0, NULL);
  354                 if (error)
  355                         skipped += 1;
  356                 dmu_tx_commit(tx);
  357 
  358                 vput(ZTOV(xzp));
  359         }
  360         zap_cursor_fini(&zc);
  361         if (error != ENOENT)
  362                 skipped += 1;
  363         return (skipped);
  364 }
  365 
  366 void
  367 zfs_rmnode(znode_t *zp)
  368 {
  369         zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
  370         objset_t        *os = zfsvfs->z_os;
  371         znode_t         *xzp = NULL;
  372         dmu_tx_t        *tx;
  373         uint64_t        acl_obj;
  374         uint64_t        xattr_obj;
  375         int             error;
  376 
  377         ASSERT(zp->z_links == 0);
  378         ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  379 
  380         /*
  381          * If this is an attribute directory, purge its contents.
  382          */
  383         if (ZTOV(zp) != NULL && ZTOV(zp)->v_type == VDIR &&
  384             (zp->z_pflags & ZFS_XATTR)) {
  385                 if (zfs_purgedir(zp) != 0) {
  386                         /*
  387                          * Not enough space to delete some xattrs.
  388                          * Leave it in the unlinked set.
  389                          */
  390                         zfs_znode_dmu_fini(zp);
  391                         zfs_znode_free(zp);
  392                         return;
  393                 }
  394         } else {
  395                 /*
  396                  * Free up all the data in the file.  We don't do this for
  397                  * XATTR directories because we need truncate and remove to be
  398                  * in the same tx, like in zfs_znode_delete(). Otherwise, if
  399                  * we crash here we'll end up with an inconsistent truncated
  400                  * zap object in the delete queue.  Note a truncated file is
  401                  * harmless since it only contains user data.
  402                  */
  403                 error = dmu_free_long_range(os, zp->z_id, 0, DMU_OBJECT_END);
  404                 if (error) {
  405                         /*
  406                          * Not enough space.  Leave the file in the unlinked
  407                          * set.
  408                          */
  409                         zfs_znode_dmu_fini(zp);
  410                         zfs_znode_free(zp);
  411                         return;
  412                 }
  413         }
  414 
  415         /*
  416          * If the file has extended attributes, we're going to unlink
  417          * the xattr dir.
  418          */
  419         error = sa_lookup(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs),
  420             &xattr_obj, sizeof (xattr_obj));
  421         if (error == 0 && xattr_obj) {
  422                 error = zfs_zget(zfsvfs, xattr_obj, &xzp);
  423                 ASSERT3S(error, ==, 0);
  424                 vn_lock(ZTOV(xzp), LK_EXCLUSIVE | LK_RETRY);
  425         }
  426 
  427         acl_obj = zfs_external_acl(zp);
  428 
  429         /*
  430          * Set up the final transaction.
  431          */
  432         tx = dmu_tx_create(os);
  433         dmu_tx_hold_free(tx, zp->z_id, 0, DMU_OBJECT_END);
  434         dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
  435         if (xzp) {
  436                 dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, TRUE, NULL);
  437                 dmu_tx_hold_sa(tx, xzp->z_sa_hdl, B_FALSE);
  438         }
  439         if (acl_obj)
  440                 dmu_tx_hold_free(tx, acl_obj, 0, DMU_OBJECT_END);
  441 
  442         zfs_sa_upgrade_txholds(tx, zp);
  443         error = dmu_tx_assign(tx, TXG_WAIT);
  444         if (error) {
  445                 /*
  446                  * Not enough space to delete the file.  Leave it in the
  447                  * unlinked set, leaking it until the fs is remounted (at
  448                  * which point we'll call zfs_unlinked_drain() to process it).
  449                  */
  450                 dmu_tx_abort(tx);
  451                 zfs_znode_dmu_fini(zp);
  452                 zfs_znode_free(zp);
  453                 goto out;
  454         }
  455 
  456         if (xzp) {
  457                 ASSERT(error == 0);
  458                 xzp->z_unlinked = B_TRUE;       /* mark xzp for deletion */
  459                 xzp->z_links = 0;       /* no more links to it */
  460                 VERIFY(0 == sa_update(xzp->z_sa_hdl, SA_ZPL_LINKS(zfsvfs),
  461                     &xzp->z_links, sizeof (xzp->z_links), tx));
  462                 zfs_unlinked_add(xzp, tx);
  463         }
  464 
  465         /* Remove this znode from the unlinked set */
  466         VERIFY3U(0, ==,
  467             zap_remove_int(zfsvfs->z_os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
  468 
  469         zfs_znode_delete(zp, tx);
  470 
  471         dmu_tx_commit(tx);
  472 out:
  473         if (xzp)
  474                 vput(ZTOV(xzp));
  475 }
  476 
  477 static uint64_t
  478 zfs_dirent(znode_t *zp, uint64_t mode)
  479 {
  480         uint64_t de = zp->z_id;
  481 
  482         if (zp->z_zfsvfs->z_version >= ZPL_VERSION_DIRENT_TYPE)
  483                 de |= IFTODT(mode) << 60;
  484         return (de);
  485 }
  486 
  487 /*
  488  * Link zp into dzp.  Can only fail if zp has been unlinked.
  489  */
  490 int
  491 zfs_link_create(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  492     int flag)
  493 {
  494         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  495         vnode_t *vp = ZTOV(zp);
  496         uint64_t value;
  497         int zp_is_dir = (vp->v_type == VDIR);
  498         sa_bulk_attr_t bulk[5];
  499         uint64_t mtime[2], ctime[2];
  500         int count = 0;
  501         int error;
  502 
  503         ASSERT_VOP_ELOCKED(ZTOV(dzp), __func__);
  504         ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  505 #if 0
  506         if (zp_is_dir) {
  507                 error = 0;
  508                 if (dzp->z_links >= LINK_MAX)
  509                         error = SET_ERROR(EMLINK);
  510                 return (error);
  511         }
  512 #endif
  513         if (!(flag & ZRENAMING)) {
  514                 if (zp->z_unlinked) {   /* no new links to unlinked zp */
  515                         ASSERT(!(flag & (ZNEW | ZEXISTS)));
  516                         return (SET_ERROR(ENOENT));
  517                 }
  518 #if 0
  519                 if (zp->z_links >= LINK_MAX) {
  520                         return (SET_ERROR(EMLINK));
  521                 }
  522 #endif
  523                 zp->z_links++;
  524                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs), NULL,
  525                     &zp->z_links, sizeof (zp->z_links));
  526 
  527         } else {
  528                 ASSERT(zp->z_unlinked == 0);
  529         }
  530         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zfsvfs), NULL,
  531             &dzp->z_id, sizeof (dzp->z_id));
  532         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
  533             &zp->z_pflags, sizeof (zp->z_pflags));
  534 
  535         if (!(flag & ZNEW)) {
  536                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
  537                     ctime, sizeof (ctime));
  538                 zfs_tstamp_update_setup(zp, STATE_CHANGED, mtime,
  539                     ctime, B_TRUE);
  540         }
  541         error = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
  542         ASSERT0(error);
  543 
  544         dzp->z_size++;
  545         dzp->z_links += zp_is_dir;
  546         count = 0;
  547         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs), NULL,
  548             &dzp->z_size, sizeof (dzp->z_size));
  549         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs), NULL,
  550             &dzp->z_links, sizeof (dzp->z_links));
  551         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL,
  552             mtime, sizeof (mtime));
  553         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
  554             ctime, sizeof (ctime));
  555         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
  556             &dzp->z_pflags, sizeof (dzp->z_pflags));
  557         zfs_tstamp_update_setup(dzp, CONTENT_MODIFIED, mtime, ctime, B_TRUE);
  558         error = sa_bulk_update(dzp->z_sa_hdl, bulk, count, tx);
  559         ASSERT0(error);
  560 
  561         value = zfs_dirent(zp, zp->z_mode);
  562         error = zap_add(zp->z_zfsvfs->z_os, dzp->z_id, name,
  563             8, 1, &value, tx);
  564         VERIFY0(error);
  565 
  566         return (0);
  567 }
  568 
  569 static int
  570 zfs_dropname(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  571     int flag)
  572 {
  573         int error;
  574 
  575         if (zp->z_zfsvfs->z_norm) {
  576                 if (zp->z_zfsvfs->z_case == ZFS_CASE_MIXED)
  577                         error = zap_remove_norm(zp->z_zfsvfs->z_os,
  578                             dzp->z_id, name, MT_EXACT, tx);
  579                 else
  580                         error = zap_remove_norm(zp->z_zfsvfs->z_os,
  581                             dzp->z_id, name, MT_FIRST, tx);
  582         } else {
  583                 error = zap_remove(zp->z_zfsvfs->z_os,
  584                     dzp->z_id, name, tx);
  585         }
  586 
  587         return (error);
  588 }
  589 
  590 /*
  591  * Unlink zp from dzp, and mark zp for deletion if this was the last link.
  592  * Can fail if zp is a mount point (EBUSY) or a non-empty directory (EEXIST).
  593  * If 'unlinkedp' is NULL, we put unlinked znodes on the unlinked list.
  594  * If it's non-NULL, we use it to indicate whether the znode needs deletion,
  595  * and it's the caller's job to do it.
  596  */
  597 int
  598 zfs_link_destroy(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
  599     int flag, boolean_t *unlinkedp)
  600 {
  601         zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
  602         vnode_t *vp = ZTOV(zp);
  603         int zp_is_dir = (vp->v_type == VDIR);
  604         boolean_t unlinked = B_FALSE;
  605         sa_bulk_attr_t bulk[5];
  606         uint64_t mtime[2], ctime[2];
  607         int count = 0;
  608         int error;
  609 
  610         ASSERT_VOP_ELOCKED(ZTOV(dzp), __func__);
  611         ASSERT_VOP_ELOCKED(ZTOV(zp), __func__);
  612 
  613         if (!(flag & ZRENAMING)) {
  614 
  615                 if (zp_is_dir && !zfs_dirempty(zp)) {
  616 #ifdef illumos
  617                         return (SET_ERROR(EEXIST));
  618 #else
  619                         return (SET_ERROR(ENOTEMPTY));
  620 #endif
  621                 }
  622 
  623                 /*
  624                  * If we get here, we are going to try to remove the object.
  625                  * First try removing the name from the directory; if that
  626                  * fails, return the error.
  627                  */
  628                 error = zfs_dropname(dzp, name, zp, tx, flag);
  629                 if (error != 0) {
  630                         return (error);
  631                 }
  632 
  633                 if (zp->z_links <= zp_is_dir) {
  634                         zfs_panic_recover("zfs: link count on vnode %p is %u, "
  635                             "should be at least %u", zp->z_vnode,
  636                             (int)zp->z_links,
  637                             zp_is_dir + 1);
  638                         zp->z_links = zp_is_dir + 1;
  639                 }
  640                 if (--zp->z_links == zp_is_dir) {
  641                         zp->z_unlinked = B_TRUE;
  642                         zp->z_links = 0;
  643                         unlinked = B_TRUE;
  644                 } else {
  645                         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs),
  646                             NULL, &ctime, sizeof (ctime));
  647                         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs),
  648                             NULL, &zp->z_pflags, sizeof (zp->z_pflags));
  649                         zfs_tstamp_update_setup(zp, STATE_CHANGED, mtime, ctime,
  650                             B_TRUE);
  651                 }
  652                 SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs),
  653                     NULL, &zp->z_links, sizeof (zp->z_links));
  654                 error = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
  655                 count = 0;
  656                 ASSERT0(error);
  657         } else {
  658                 ASSERT(zp->z_unlinked == 0);
  659                 error = zfs_dropname(dzp, name, zp, tx, flag);
  660                 if (error != 0)
  661                         return (error);
  662         }
  663 
  664         dzp->z_size--;          /* one dirent removed */
  665         dzp->z_links -= zp_is_dir;      /* ".." link from zp */
  666         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_LINKS(zfsvfs),
  667             NULL, &dzp->z_links, sizeof (dzp->z_links));
  668         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_SIZE(zfsvfs),
  669             NULL, &dzp->z_size, sizeof (dzp->z_size));
  670         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs),
  671             NULL, ctime, sizeof (ctime));
  672         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs),
  673             NULL, mtime, sizeof (mtime));
  674         SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs),
  675             NULL, &dzp->z_pflags, sizeof (dzp->z_pflags));
  676         zfs_tstamp_update_setup(dzp, CONTENT_MODIFIED, mtime, ctime, B_TRUE);
  677         error = sa_bulk_update(dzp->z_sa_hdl, bulk, count, tx);
  678         ASSERT0(error);
  679 
  680         if (unlinkedp != NULL)
  681                 *unlinkedp = unlinked;
  682         else if (unlinked)
  683                 zfs_unlinked_add(zp, tx);
  684 
  685         return (0);
  686 }
  687 
  688 /*
  689  * Indicate whether the directory is empty.
  690  */
  691 boolean_t
  692 zfs_dirempty(znode_t *dzp)
  693 {
  694         return (dzp->z_size == 2);
  695 }
  696 
  697 int
  698 zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr)
  699 {
  700         zfsvfs_t *zfsvfs = zp->z_zfsvfs;
  701         znode_t *xzp;
  702         dmu_tx_t *tx;
  703         int error;
  704         zfs_acl_ids_t acl_ids;
  705         boolean_t fuid_dirtied;
  706         uint64_t parent;
  707 
  708         *xvpp = NULL;
  709 
  710         /*
  711          * In FreeBSD, access checking for creating an EA is being done
  712          * in zfs_setextattr(),
  713          */
  714 #ifndef __FreeBSD_kernel__
  715         if (error = zfs_zaccess(zp, ACE_WRITE_NAMED_ATTRS, 0, B_FALSE, cr))
  716                 return (error);
  717 #endif
  718 
  719         if ((error = zfs_acl_ids_create(zp, IS_XATTR, vap, cr, NULL,
  720             &acl_ids)) != 0)
  721                 return (error);
  722         if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
  723                 zfs_acl_ids_free(&acl_ids);
  724                 return (SET_ERROR(EDQUOT));
  725         }
  726 
  727         getnewvnode_reserve(1);
  728 
  729         tx = dmu_tx_create(zfsvfs->z_os);
  730         dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
  731             ZFS_SA_BASE_ATTR_SIZE);
  732         dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
  733         dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
  734         fuid_dirtied = zfsvfs->z_fuid_dirty;
  735         if (fuid_dirtied)
  736                 zfs_fuid_txhold(zfsvfs, tx);
  737         error = dmu_tx_assign(tx, TXG_WAIT);
  738         if (error) {
  739                 zfs_acl_ids_free(&acl_ids);
  740                 dmu_tx_abort(tx);
  741                 return (error);
  742         }
  743         zfs_mknode(zp, vap, tx, cr, IS_XATTR, &xzp, &acl_ids);
  744 
  745         if (fuid_dirtied)
  746                 zfs_fuid_sync(zfsvfs, tx);
  747 
  748 #ifdef DEBUG
  749         error = sa_lookup(xzp->z_sa_hdl, SA_ZPL_PARENT(zfsvfs),
  750             &parent, sizeof (parent));
  751         ASSERT(error == 0 && parent == zp->z_id);
  752 #endif
  753 
  754         VERIFY(0 == sa_update(zp->z_sa_hdl, SA_ZPL_XATTR(zfsvfs), &xzp->z_id,
  755             sizeof (xzp->z_id), tx));
  756 
  757         (void) zfs_log_create(zfsvfs->z_log, tx, TX_MKXATTR, zp,
  758             xzp, "", NULL, acl_ids.z_fuidp, vap);
  759 
  760         zfs_acl_ids_free(&acl_ids);
  761         dmu_tx_commit(tx);
  762 
  763         getnewvnode_drop_reserve();
  764 
  765         *xvpp = ZTOV(xzp);
  766 
  767         return (0);
  768 }
  769 
  770 /*
  771  * Return a znode for the extended attribute directory for zp.
  772  * ** If the directory does not already exist, it is created **
  773  *
  774  *      IN:     zp      - znode to obtain attribute directory from
  775  *              cr      - credentials of caller
  776  *              flags   - flags from the VOP_LOOKUP call
  777  *
  778  *      OUT:    xzpp    - pointer to extended attribute znode
  779  *
  780  *      RETURN: 0 on success
  781  *              error number on failure
  782  */
  783 int
  784 zfs_get_xattrdir(znode_t *zp, vnode_t **xvpp, cred_t *cr, int flags)
  785 {
  786         zfsvfs_t        *zfsvfs = zp->z_zfsvfs;
  787         znode_t         *xzp;
  788         vattr_t         va;
  789         int             error;
  790 top:
  791         error = zfs_dirent_lookup(zp, "", &xzp, ZXATTR);
  792         if (error)
  793                 return (error);
  794 
  795         if (xzp != NULL) {
  796                 *xvpp = ZTOV(xzp);
  797                 return (0);
  798         }
  799 
  800 
  801         if (!(flags & CREATE_XATTR_DIR)) {
  802 #ifdef illumos
  803                 return (SET_ERROR(ENOENT));
  804 #else
  805                 return (SET_ERROR(ENOATTR));
  806 #endif
  807         }
  808 
  809         if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) {
  810                 return (SET_ERROR(EROFS));
  811         }
  812 
  813         /*
  814          * The ability to 'create' files in an attribute
  815          * directory comes from the write_xattr permission on the base file.
  816          *
  817          * The ability to 'search' an attribute directory requires
  818          * read_xattr permission on the base file.
  819          *
  820          * Once in a directory the ability to read/write attributes
  821          * is controlled by the permissions on the attribute file.
  822          */
  823         va.va_mask = AT_TYPE | AT_MODE | AT_UID | AT_GID;
  824         va.va_type = VDIR;
  825         va.va_mode = S_IFDIR | S_ISVTX | 0777;
  826         zfs_fuid_map_ids(zp, cr, &va.va_uid, &va.va_gid);
  827 
  828         error = zfs_make_xattrdir(zp, &va, xvpp, cr);
  829 
  830         if (error == ERESTART) {
  831                 /* NB: we already did dmu_tx_wait() if necessary */
  832                 goto top;
  833         }
  834         if (error == 0)
  835                 VOP_UNLOCK(*xvpp, 0);
  836 
  837         return (error);
  838 }
  839 
  840 /*
  841  * Decide whether it is okay to remove within a sticky directory.
  842  *
  843  * In sticky directories, write access is not sufficient;
  844  * you can remove entries from a directory only if:
  845  *
  846  *      you own the directory,
  847  *      you own the entry,
  848  *      the entry is a plain file and you have write access,
  849  *      or you are privileged (checked in secpolicy...).
  850  *
  851  * The function returns 0 if remove access is granted.
  852  */
  853 int
  854 zfs_sticky_remove_access(znode_t *zdp, znode_t *zp, cred_t *cr)
  855 {
  856         uid_t           uid;
  857         uid_t           downer;
  858         uid_t           fowner;
  859         zfsvfs_t        *zfsvfs = zdp->z_zfsvfs;
  860 
  861         if (zdp->z_zfsvfs->z_replay)
  862                 return (0);
  863 
  864         if ((zdp->z_mode & S_ISVTX) == 0)
  865                 return (0);
  866 
  867         downer = zfs_fuid_map_id(zfsvfs, zdp->z_uid, cr, ZFS_OWNER);
  868         fowner = zfs_fuid_map_id(zfsvfs, zp->z_uid, cr, ZFS_OWNER);
  869 
  870         if ((uid = crgetuid(cr)) == downer || uid == fowner ||
  871             (ZTOV(zp)->v_type == VREG &&
  872             zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr) == 0))
  873                 return (0);
  874         else
  875                 return (secpolicy_vnode_remove(ZTOV(zp), cr));
  876 }

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