Move the world out of /zfs/ and seperate out module build tree

1 files changed, 977 insertions, 0 deletions

diff --git a/module/zfs/zfs_dir.c b/module/zfs/zfs_dir.c
new file mode 100644
index 000000000..1ec493264
--- /dev/null
+++ b/module/zfs/zfs_dir.c
@@ -0,0 +1,977 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/systm.h>
+#include <sys/sysmacros.h>
+#include <sys/resource.h>
+#include <sys/vfs.h>
+#include <sys/vnode.h>
+#include <sys/file.h>
+#include <sys/mode.h>
+#include <sys/kmem.h>
+#include <sys/uio.h>
+#include <sys/pathname.h>
+#include <sys/cmn_err.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
+#include <sys/unistd.h>
+#include <sys/sunddi.h>
+#include <sys/random.h>
+#include <sys/policy.h>
+#include <sys/zfs_dir.h>
+#include <sys/zfs_acl.h>
+#include <sys/fs/zfs.h>
+#include "fs/fs_subr.h"
+#include <sys/zap.h>
+#include <sys/dmu.h>
+#include <sys/atomic.h>
+#include <sys/zfs_ctldir.h>
+#include <sys/zfs_fuid.h>
+#include <sys/dnlc.h>
+#include <sys/extdirent.h>
+
+/*
+ * zfs_match_find() is used by zfs_dirent_lock() to peform zap lookups
+ * of names after deciding which is the appropriate lookup interface.
+ */
+static int
+zfs_match_find(zfsvfs_t *zfsvfs, znode_t *dzp, char *name, boolean_t exact,
+    boolean_t update, int *deflags, pathname_t *rpnp, uint64_t *zoid)
+{
+	int error;
+
+	if (zfsvfs->z_norm) {
+		matchtype_t mt = MT_FIRST;
+		boolean_t conflict = B_FALSE;
+		size_t bufsz = 0;
+		char *buf = NULL;
+
+		if (rpnp) {
+			buf = rpnp->pn_buf;
+			bufsz = rpnp->pn_bufsize;
+		}
+		if (exact)
+			mt = MT_EXACT;
+		/*
+		 * In the non-mixed case we only expect there would ever
+		 * be one match, but we need to use the normalizing lookup.
+		 */
+		error = zap_lookup_norm(zfsvfs->z_os, dzp->z_id, name, 8, 1,
+		    zoid, mt, buf, bufsz, &conflict);
+		if (!error && deflags)
+			*deflags = conflict ? ED_CASE_CONFLICT : 0;
+	} else {
+		error = zap_lookup(zfsvfs->z_os, dzp->z_id, name, 8, 1, zoid);
+	}
+	*zoid = ZFS_DIRENT_OBJ(*zoid);
+
+	if (error == ENOENT && update)
+		dnlc_update(ZTOV(dzp), name, DNLC_NO_VNODE);
+
+	return (error);
+}
+
+/*
+ * Lock a directory entry.  A dirlock on <dzp, name> protects that name
+ * in dzp's directory zap object.  As long as you hold a dirlock, you can
+ * assume two things: (1) dzp cannot be reaped, and (2) no other thread
+ * can change the zap entry for (i.e. link or unlink) this name.
+ *
+ * Input arguments:
+ *	dzp	- znode for directory
+ *	name	- name of entry to lock
+ *	flag	- ZNEW: if the entry already exists, fail with EEXIST.
+ *		  ZEXISTS: if the entry does not exist, fail with ENOENT.
+ *		  ZSHARED: allow concurrent access with other ZSHARED callers.
+ *		  ZXATTR: we want dzp's xattr directory
+ *		  ZCILOOK: On a mixed sensitivity file system,
+ *			   this lookup should be case-insensitive.
+ *		  ZCIEXACT: On a purely case-insensitive file system,
+ *			    this lookup should be case-sensitive.
+ *		  ZRENAMING: we are locking for renaming, force narrow locks
+ *
+ * Output arguments:
+ *	zpp	- pointer to the znode for the entry (NULL if there isn't one)
+ *	dlpp	- pointer to the dirlock for this entry (NULL on error)
+ *      direntflags - (case-insensitive lookup only)
+ *		flags if multiple case-sensitive matches exist in directory
+ *      realpnp     - (case-insensitive lookup only)
+ *		actual name matched within the directory
+ *
+ * Return value: 0 on success or errno on failure.
+ *
+ * NOTE: Always checks for, and rejects, '.' and '..'.
+ * NOTE: For case-insensitive file systems we take wide locks (see below),
+ *	 but return znode pointers to a single match.
+ */
+int
+zfs_dirent_lock(zfs_dirlock_t **dlpp, znode_t *dzp, char *name, znode_t **zpp,
+    int flag, int *direntflags, pathname_t *realpnp)
+{
+	zfsvfs_t	*zfsvfs = dzp->z_zfsvfs;
+	zfs_dirlock_t	*dl;
+	boolean_t	update;
+	boolean_t	exact;
+	uint64_t	zoid;
+	vnode_t		*vp = NULL;
+	int		error = 0;
+	int		cmpflags;
+
+	*zpp = NULL;
+	*dlpp = NULL;
+
+	/*
+	 * Verify that we are not trying to lock '.', '..', or '.zfs'
+	 */
+	if (name[0] == '.' &&
+	    (name[1] == '\0' || (name[1] == '.' && name[2] == '\0')) ||
+	    zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0)
+		return (EEXIST);
+
+	/*
+	 * Case sensitivity and normalization preferences are set when
+	 * the file system is created.  These are stored in the
+	 * zfsvfs->z_case and zfsvfs->z_norm fields.  These choices
+	 * affect what vnodes can be cached in the DNLC, how we
+	 * perform zap lookups, and the "width" of our dirlocks.
+	 *
+	 * A normal dirlock locks a single name.  Note that with
+	 * normalization a name can be composed multiple ways, but
+	 * when normalized, these names all compare equal.  A wide
+	 * dirlock locks multiple names.  We need these when the file
+	 * system is supporting mixed-mode access.  It is sometimes
+	 * necessary to lock all case permutations of file name at
+	 * once so that simultaneous case-insensitive/case-sensitive
+	 * behaves as rationally as possible.
+	 */
+
+	/*
+	 * Decide if exact matches should be requested when performing
+	 * a zap lookup on file systems supporting case-insensitive
+	 * access.
+	 */
+	exact =
+	    ((zfsvfs->z_case == ZFS_CASE_INSENSITIVE) && (flag & ZCIEXACT)) ||
+	    ((zfsvfs->z_case == ZFS_CASE_MIXED) && !(flag & ZCILOOK));
+
+	/*
+	 * Only look in or update the DNLC if we are looking for the
+	 * name on a file system that does not require normalization
+	 * or case folding.  We can also look there if we happen to be
+	 * on a non-normalizing, mixed sensitivity file system IF we
+	 * are looking for the exact name.
+	 *
+	 * Maybe can add TO-UPPERed version of name to dnlc in ci-only
+	 * case for performance improvement?
+	 */
+	update = !zfsvfs->z_norm ||
+	    ((zfsvfs->z_case == ZFS_CASE_MIXED) &&
+	    !(zfsvfs->z_norm & ~U8_TEXTPREP_TOUPPER) && !(flag & ZCILOOK));
+
+	/*
+	 * ZRENAMING indicates we are in a situation where we should
+	 * take narrow locks regardless of the file system's
+	 * preferences for normalizing and case folding.  This will
+	 * prevent us deadlocking trying to grab the same wide lock
+	 * twice if the two names happen to be case-insensitive
+	 * matches.
+	 */
+	if (flag & ZRENAMING)
+		cmpflags = 0;
+	else
+		cmpflags = zfsvfs->z_norm;
+
+	/*
+	 * Wait until there are no locks on this name.
+	 */
+	rw_enter(&dzp->z_name_lock, RW_READER);
+	mutex_enter(&dzp->z_lock);
+	for (;;) {
+		if (dzp->z_unlinked) {
+			mutex_exit(&dzp->z_lock);
+			rw_exit(&dzp->z_name_lock);
+			return (ENOENT);
+		}
+		for (dl = dzp->z_dirlocks; dl != NULL; dl = dl->dl_next) {
+			if ((u8_strcmp(name, dl->dl_name, 0, cmpflags,
+			    U8_UNICODE_LATEST, &error) == 0) || error != 0)
+				break;
+		}
+		if (error != 0) {
+			mutex_exit(&dzp->z_lock);
+			rw_exit(&dzp->z_name_lock);
+			return (ENOENT);
+		}
+		if (dl == NULL)	{
+			/*
+			 * Allocate a new dirlock and add it to the list.
+			 */
+			dl = kmem_alloc(sizeof (zfs_dirlock_t), KM_SLEEP);
+			cv_init(&dl->dl_cv, NULL, CV_DEFAULT, NULL);
+			dl->dl_name = name;
+			dl->dl_sharecnt = 0;
+			dl->dl_namesize = 0;
+			dl->dl_dzp = dzp;
+			dl->dl_next = dzp->z_dirlocks;
+			dzp->z_dirlocks = dl;
+			break;
+		}
+		if ((flag & ZSHARED) && dl->dl_sharecnt != 0)
+			break;
+		cv_wait(&dl->dl_cv, &dzp->z_lock);
+	}
+
+	if ((flag & ZSHARED) && ++dl->dl_sharecnt > 1 && dl->dl_namesize == 0) {
+		/*
+		 * We're the second shared reference to dl.  Make a copy of
+		 * dl_name in case the first thread goes away before we do.
+		 * Note that we initialize the new name before storing its
+		 * pointer into dl_name, because the first thread may load
+		 * dl->dl_name at any time.  He'll either see the old value,
+		 * which is his, or the new shared copy; either is OK.
+		 */
+		dl->dl_namesize = strlen(dl->dl_name) + 1;
+		name = kmem_alloc(dl->dl_namesize, KM_SLEEP);
+		bcopy(dl->dl_name, name, dl->dl_namesize);
+		dl->dl_name = name;
+	}
+
+	mutex_exit(&dzp->z_lock);
+
+	/*
+	 * We have a dirlock on the name.  (Note that it is the dirlock,
+	 * not the dzp's z_lock, that protects the name in the zap object.)
+	 * See if there's an object by this name; if so, put a hold on it.
+	 */
+	if (flag & ZXATTR) {
+		zoid = dzp->z_phys->zp_xattr;
+		error = (zoid == 0 ? ENOENT : 0);
+	} else {
+		if (update)
+			vp = dnlc_lookup(ZTOV(dzp), name);
+		if (vp == DNLC_NO_VNODE) {
+			VN_RELE(vp);
+			error = ENOENT;
+		} else if (vp) {
+			if (flag & ZNEW) {
+				zfs_dirent_unlock(dl);
+				VN_RELE(vp);
+				return (EEXIST);
+			}
+			*dlpp = dl;
+			*zpp = VTOZ(vp);
+			return (0);
+		} else {
+			error = zfs_match_find(zfsvfs, dzp, name, exact,
+			    update, direntflags, realpnp, &zoid);
+		}
+	}
+	if (error) {
+		if (error != ENOENT || (flag & ZEXISTS)) {
+			zfs_dirent_unlock(dl);
+			return (error);
+		}
+	} else {
+		if (flag & ZNEW) {
+			zfs_dirent_unlock(dl);
+			return (EEXIST);
+		}
+		error = zfs_zget(zfsvfs, zoid, zpp);
+		if (error) {
+			zfs_dirent_unlock(dl);
+			return (error);
+		}
+		if (!(flag & ZXATTR) && update)
+			dnlc_update(ZTOV(dzp), name, ZTOV(*zpp));
+	}
+
+	*dlpp = dl;
+
+	return (0);
+}
+
+/*
+ * Unlock this directory entry and wake anyone who was waiting for it.
+ */
+void
+zfs_dirent_unlock(zfs_dirlock_t *dl)
+{
+	znode_t *dzp = dl->dl_dzp;
+	zfs_dirlock_t **prev_dl, *cur_dl;
+
+	mutex_enter(&dzp->z_lock);
+	rw_exit(&dzp->z_name_lock);
+	if (dl->dl_sharecnt > 1) {
+		dl->dl_sharecnt--;
+		mutex_exit(&dzp->z_lock);
+		return;
+	}
+	prev_dl = &dzp->z_dirlocks;
+	while ((cur_dl = *prev_dl) != dl)
+		prev_dl = &cur_dl->dl_next;
+	*prev_dl = dl->dl_next;
+	cv_broadcast(&dl->dl_cv);
+	mutex_exit(&dzp->z_lock);
+
+	if (dl->dl_namesize != 0)
+		kmem_free(dl->dl_name, dl->dl_namesize);
+	cv_destroy(&dl->dl_cv);
+	kmem_free(dl, sizeof (*dl));
+}
+
+/*
+ * Look up an entry in a directory.
+ *
+ * NOTE: '.' and '..' are handled as special cases because
+ *	no directory entries are actually stored for them.  If this is
+ *	the root of a filesystem, then '.zfs' is also treated as a
+ *	special pseudo-directory.
+ */
+int
+zfs_dirlook(znode_t *dzp, char *name, vnode_t **vpp, int flags,
+    int *deflg, pathname_t *rpnp)
+{
+	zfs_dirlock_t *dl;
+	znode_t *zp;
+	int error = 0;
+
+	if (name[0] == 0 || (name[0] == '.' && name[1] == 0)) {
+		*vpp = ZTOV(dzp);
+		VN_HOLD(*vpp);
+	} else if (name[0] == '.' && name[1] == '.' && name[2] == 0) {
+		zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
+		/*
+		 * If we are a snapshot mounted under .zfs, return
+		 * the vp for the snapshot directory.
+		 */
+		if (dzp->z_phys->zp_parent == dzp->z_id &&
+		    zfsvfs->z_parent != zfsvfs) {
+			error = zfsctl_root_lookup(zfsvfs->z_parent->z_ctldir,
+			    "snapshot", vpp, NULL, 0, NULL, kcred,
+			    NULL, NULL, NULL);
+			return (error);
+		}
+		rw_enter(&dzp->z_parent_lock, RW_READER);
+		error = zfs_zget(zfsvfs, dzp->z_phys->zp_parent, &zp);
+		if (error == 0)
+			*vpp = ZTOV(zp);
+		rw_exit(&dzp->z_parent_lock);
+	} else if (zfs_has_ctldir(dzp) && strcmp(name, ZFS_CTLDIR_NAME) == 0) {
+		*vpp = zfsctl_root(dzp);
+	} else {
+		int zf;
+
+		zf = ZEXISTS | ZSHARED;
+		if (flags & FIGNORECASE)
+			zf |= ZCILOOK;
+
+		error = zfs_dirent_lock(&dl, dzp, name, &zp, zf, deflg, rpnp);
+		if (error == 0) {
+			*vpp = ZTOV(zp);
+			zfs_dirent_unlock(dl);
+			dzp->z_zn_prefetch = B_TRUE; /* enable prefetching */
+		}
+		rpnp = NULL;
+	}
+
+	if ((flags & FIGNORECASE) && rpnp && !error)
+		(void) strlcpy(rpnp->pn_buf, name, rpnp->pn_bufsize);
+
+	return (error);
+}
+
+/*
+ * unlinked Set (formerly known as the "delete queue") Error Handling
+ *
+ * When dealing with the unlinked set, we dmu_tx_hold_zap(), but we
+ * don't specify the name of the entry that we will be manipulating.  We
+ * also fib and say that we won't be adding any new entries to the
+ * unlinked set, even though we might (this is to lower the minimum file
+ * size that can be deleted in a full filesystem).  So on the small
+ * chance that the nlink list is using a fat zap (ie. has more than
+ * 2000 entries), we *may* not pre-read a block that's needed.
+ * Therefore it is remotely possible for some of the assertions
+ * regarding the unlinked set below to fail due to i/o error.  On a
+ * nondebug system, this will result in the space being leaked.
+ */
+void
+zfs_unlinked_add(znode_t *zp, dmu_tx_t *tx)
+{
+	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
+
+	ASSERT(zp->z_unlinked);
+	ASSERT3U(zp->z_phys->zp_links, ==, 0);
+
+	VERIFY3U(0, ==,
+	    zap_add_int(zfsvfs->z_os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
+}
+
+/*
+ * Clean up any znodes that had no links when we either crashed or
+ * (force) umounted the file system.
+ */
+void
+zfs_unlinked_drain(zfsvfs_t *zfsvfs)
+{
+	zap_cursor_t	zc;
+	zap_attribute_t zap;
+	dmu_object_info_t doi;
+	znode_t		*zp;
+	int		error;
+
+	/*
+	 * Interate over the contents of the unlinked set.
+	 */
+	for (zap_cursor_init(&zc, zfsvfs->z_os, zfsvfs->z_unlinkedobj);
+	    zap_cursor_retrieve(&zc, &zap) == 0;
+	    zap_cursor_advance(&zc)) {
+
+		/*
+		 * See what kind of object we have in list
+		 */
+
+		error = dmu_object_info(zfsvfs->z_os,
+		    zap.za_first_integer, &doi);
+		if (error != 0)
+			continue;
+
+		ASSERT((doi.doi_type == DMU_OT_PLAIN_FILE_CONTENTS) ||
+		    (doi.doi_type == DMU_OT_DIRECTORY_CONTENTS));
+		/*
+		 * We need to re-mark these list entries for deletion,
+		 * so we pull them back into core and set zp->z_unlinked.
+		 */
+		error = zfs_zget(zfsvfs, zap.za_first_integer, &zp);
+
+		/*
+		 * We may pick up znodes that are already marked for deletion.
+		 * This could happen during the purge of an extended attribute
+		 * directory.  All we need to do is skip over them, since they
+		 * are already in the system marked z_unlinked.
+		 */
+		if (error != 0)
+			continue;
+
+		zp->z_unlinked = B_TRUE;
+		VN_RELE(ZTOV(zp));
+	}
+	zap_cursor_fini(&zc);
+}
+
+/*
+ * Delete the entire contents of a directory.  Return a count
+ * of the number of entries that could not be deleted. If we encounter
+ * an error, return a count of at least one so that the directory stays
+ * in the unlinked set.
+ *
+ * NOTE: this function assumes that the directory is inactive,
+ *	so there is no need to lock its entries before deletion.
+ *	Also, it assumes the directory contents is *only* regular
+ *	files.
+ */
+static int
+zfs_purgedir(znode_t *dzp)
+{
+	zap_cursor_t	zc;
+	zap_attribute_t	zap;
+	znode_t		*xzp;
+	dmu_tx_t	*tx;
+	zfsvfs_t	*zfsvfs = dzp->z_zfsvfs;
+	zfs_dirlock_t	dl;
+	int skipped = 0;
+	int error;
+
+	for (zap_cursor_init(&zc, zfsvfs->z_os, dzp->z_id);
+	    (error = zap_cursor_retrieve(&zc, &zap)) == 0;
+	    zap_cursor_advance(&zc)) {
+		error = zfs_zget(zfsvfs,
+		    ZFS_DIRENT_OBJ(zap.za_first_integer), &xzp);
+		if (error) {
+			skipped += 1;
+			continue;
+		}
+
+		ASSERT((ZTOV(xzp)->v_type == VREG) ||
+		    (ZTOV(xzp)->v_type == VLNK));
+
+		tx = dmu_tx_create(zfsvfs->z_os);
+		dmu_tx_hold_bonus(tx, dzp->z_id);
+		dmu_tx_hold_zap(tx, dzp->z_id, FALSE, zap.za_name);
+		dmu_tx_hold_bonus(tx, xzp->z_id);
+		dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
+		error = dmu_tx_assign(tx, TXG_WAIT);
+		if (error) {
+			dmu_tx_abort(tx);
+			VN_RELE(ZTOV(xzp));
+			skipped += 1;
+			continue;
+		}
+		bzero(&dl, sizeof (dl));
+		dl.dl_dzp = dzp;
+		dl.dl_name = zap.za_name;
+
+		error = zfs_link_destroy(&dl, xzp, tx, 0, NULL);
+		if (error)
+			skipped += 1;
+		dmu_tx_commit(tx);
+
+		VN_RELE(ZTOV(xzp));
+	}
+	zap_cursor_fini(&zc);
+	if (error != ENOENT)
+		skipped += 1;
+	return (skipped);
+}
+
+void
+zfs_rmnode(znode_t *zp)
+{
+	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
+	objset_t	*os = zfsvfs->z_os;
+	znode_t		*xzp = NULL;
+	dmu_tx_t	*tx;
+	uint64_t	acl_obj;
+	int		error;
+
+	ASSERT(ZTOV(zp)->v_count == 0);
+	ASSERT(zp->z_phys->zp_links == 0);
+
+	/*
+	 * If this is a ZIL replay then leave the object in the unlinked set.
+	 * Otherwise we can get a deadlock, because the delete can be
+	 * quite large and span multiple tx's and txgs, but each replay
+	 * creates a tx to atomically run the replay function and mark the
+	 * replay record as complete. We deadlock trying to start a tx in
+	 * a new txg to further the deletion but can't because the replay
+	 * tx hasn't finished.
+	 *
+	 * We actually delete the object if we get a failure to create an
+	 * object in zil_replay_log_record(), or after calling zil_replay().
+	 */
+	if (zfsvfs->z_assign >= TXG_INITIAL) {
+		zfs_znode_dmu_fini(zp);
+		zfs_znode_free(zp);
+		return;
+	}
+
+	/*
+	 * If this is an attribute directory, purge its contents.
+	 */
+	if (ZTOV(zp)->v_type == VDIR && (zp->z_phys->zp_flags & ZFS_XATTR)) {
+		if (zfs_purgedir(zp) != 0) {
+			/*
+			 * Not enough space to delete some xattrs.
+			 * Leave it in the unlinked set.
+			 */
+			zfs_znode_dmu_fini(zp);
+			zfs_znode_free(zp);
+			return;
+		}
+	}
+
+	/*
+	 * Free up all the data in the file.
+	 */
+	error = dmu_free_long_range(os, zp->z_id, 0, DMU_OBJECT_END);
+	if (error) {
+		/*
+		 * Not enough space.  Leave the file in the unlinked set.
+		 */
+		zfs_znode_dmu_fini(zp);
+		zfs_znode_free(zp);
+		return;
+	}
+
+	/*
+	 * If the file has extended attributes, we're going to unlink
+	 * the xattr dir.
+	 */
+	if (zp->z_phys->zp_xattr) {
+		error = zfs_zget(zfsvfs, zp->z_phys->zp_xattr, &xzp);
+		ASSERT(error == 0);
+	}
+
+	acl_obj = zp->z_phys->zp_acl.z_acl_extern_obj;
+
+	/*
+	 * Set up the final transaction.
+	 */
+	tx = dmu_tx_create(os);
+	dmu_tx_hold_free(tx, zp->z_id, 0, DMU_OBJECT_END);
+	dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, FALSE, NULL);
+	if (xzp) {
+		dmu_tx_hold_bonus(tx, xzp->z_id);
+		dmu_tx_hold_zap(tx, zfsvfs->z_unlinkedobj, TRUE, NULL);
+	}
+	if (acl_obj)
+		dmu_tx_hold_free(tx, acl_obj, 0, DMU_OBJECT_END);
+	error = dmu_tx_assign(tx, TXG_WAIT);
+	if (error) {
+		/*
+		 * Not enough space to delete the file.  Leave it in the
+		 * unlinked set, leaking it until the fs is remounted (at
+		 * which point we'll call zfs_unlinked_drain() to process it).
+		 */
+		dmu_tx_abort(tx);
+		zfs_znode_dmu_fini(zp);
+		zfs_znode_free(zp);
+		goto out;
+	}
+
+	if (xzp) {
+		dmu_buf_will_dirty(xzp->z_dbuf, tx);
+		mutex_enter(&xzp->z_lock);
+		xzp->z_unlinked = B_TRUE;	/* mark xzp for deletion */
+		xzp->z_phys->zp_links = 0;	/* no more links to it */
+		mutex_exit(&xzp->z_lock);
+		zfs_unlinked_add(xzp, tx);
+	}
+
+	/* Remove this znode from the unlinked set */
+	VERIFY3U(0, ==,
+	    zap_remove_int(zfsvfs->z_os, zfsvfs->z_unlinkedobj, zp->z_id, tx));
+
+	zfs_znode_delete(zp, tx);
+
+	dmu_tx_commit(tx);
+out:
+	if (xzp)
+		VN_RELE(ZTOV(xzp));
+}
+
+static uint64_t
+zfs_dirent(znode_t *zp)
+{
+	uint64_t de = zp->z_id;
+	if (zp->z_zfsvfs->z_version >= ZPL_VERSION_DIRENT_TYPE)
+		de |= IFTODT((zp)->z_phys->zp_mode) << 60;
+	return (de);
+}
+
+/*
+ * Link zp into dl.  Can only fail if zp has been unlinked.
+ */
+int
+zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
+{
+	znode_t *dzp = dl->dl_dzp;
+	vnode_t *vp = ZTOV(zp);
+	uint64_t value;
+	int zp_is_dir = (vp->v_type == VDIR);
+	int error;
+
+	dmu_buf_will_dirty(zp->z_dbuf, tx);
+	mutex_enter(&zp->z_lock);
+
+	if (!(flag & ZRENAMING)) {
+		if (zp->z_unlinked) {	/* no new links to unlinked zp */
+			ASSERT(!(flag & (ZNEW | ZEXISTS)));
+			mutex_exit(&zp->z_lock);
+			return (ENOENT);
+		}
+		zp->z_phys->zp_links++;
+	}
+	zp->z_phys->zp_parent = dzp->z_id;	/* dzp is now zp's parent */
+
+	if (!(flag & ZNEW))
+		zfs_time_stamper_locked(zp, STATE_CHANGED, tx);
+	mutex_exit(&zp->z_lock);
+
+	dmu_buf_will_dirty(dzp->z_dbuf, tx);
+	mutex_enter(&dzp->z_lock);
+	dzp->z_phys->zp_size++;			/* one dirent added */
+	dzp->z_phys->zp_links += zp_is_dir;	/* ".." link from zp */
+	zfs_time_stamper_locked(dzp, CONTENT_MODIFIED, tx);
+	mutex_exit(&dzp->z_lock);
+
+	value = zfs_dirent(zp);
+	error = zap_add(zp->z_zfsvfs->z_os, dzp->z_id, dl->dl_name,
+	    8, 1, &value, tx);
+	ASSERT(error == 0);
+
+	dnlc_update(ZTOV(dzp), dl->dl_name, vp);
+
+	return (0);
+}
+
+/*
+ * Unlink zp from dl, and mark zp for deletion if this was the last link.
+ * Can fail if zp is a mount point (EBUSY) or a non-empty directory (EEXIST).
+ * If 'unlinkedp' is NULL, we put unlinked znodes on the unlinked list.
+ * If it's non-NULL, we use it to indicate whether the znode needs deletion,
+ * and it's the caller's job to do it.
+ */
+int
+zfs_link_destroy(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag,
+	boolean_t *unlinkedp)
+{
+	znode_t *dzp = dl->dl_dzp;
+	vnode_t *vp = ZTOV(zp);
+	int zp_is_dir = (vp->v_type == VDIR);
+	boolean_t unlinked = B_FALSE;
+	int error;
+
+	dnlc_remove(ZTOV(dzp), dl->dl_name);
+
+	if (!(flag & ZRENAMING)) {
+		dmu_buf_will_dirty(zp->z_dbuf, tx);
+
+		if (vn_vfswlock(vp))		/* prevent new mounts on zp */
+			return (EBUSY);
+
+		if (vn_ismntpt(vp)) {		/* don't remove mount point */
+			vn_vfsunlock(vp);
+			return (EBUSY);
+		}
+
+		mutex_enter(&zp->z_lock);
+		if (zp_is_dir && !zfs_dirempty(zp)) {	/* dir not empty */
+			mutex_exit(&zp->z_lock);
+			vn_vfsunlock(vp);
+			return (EEXIST);
+		}
+		if (zp->z_phys->zp_links <= zp_is_dir) {
+			zfs_panic_recover("zfs: link count on %s is %u, "
+			    "should be at least %u",
+			    zp->z_vnode->v_path ? zp->z_vnode->v_path :
+			    "<unknown>", (int)zp->z_phys->zp_links,
+			    zp_is_dir + 1);
+			zp->z_phys->zp_links = zp_is_dir + 1;
+		}
+		if (--zp->z_phys->zp_links == zp_is_dir) {
+			zp->z_unlinked = B_TRUE;
+			zp->z_phys->zp_links = 0;
+			unlinked = B_TRUE;
+		} else {
+			zfs_time_stamper_locked(zp, STATE_CHANGED, tx);
+		}
+		mutex_exit(&zp->z_lock);
+		vn_vfsunlock(vp);
+	}
+
+	dmu_buf_will_dirty(dzp->z_dbuf, tx);
+	mutex_enter(&dzp->z_lock);
+	dzp->z_phys->zp_size--;			/* one dirent removed */
+	dzp->z_phys->zp_links -= zp_is_dir;	/* ".." link from zp */
+	zfs_time_stamper_locked(dzp, CONTENT_MODIFIED, tx);
+	mutex_exit(&dzp->z_lock);
+
+	if (zp->z_zfsvfs->z_norm) {
+		if (((zp->z_zfsvfs->z_case == ZFS_CASE_INSENSITIVE) &&
+		    (flag & ZCIEXACT)) ||
+		    ((zp->z_zfsvfs->z_case == ZFS_CASE_MIXED) &&
+		    !(flag & ZCILOOK)))
+			error = zap_remove_norm(zp->z_zfsvfs->z_os,
+			    dzp->z_id, dl->dl_name, MT_EXACT, tx);
+		else
+			error = zap_remove_norm(zp->z_zfsvfs->z_os,
+			    dzp->z_id, dl->dl_name, MT_FIRST, tx);
+	} else {
+		error = zap_remove(zp->z_zfsvfs->z_os,
+		    dzp->z_id, dl->dl_name, tx);
+	}
+	ASSERT(error == 0);
+
+	if (unlinkedp != NULL)
+		*unlinkedp = unlinked;
+	else if (unlinked)
+		zfs_unlinked_add(zp, tx);
+
+	return (0);
+}
+
+/*
+ * Indicate whether the directory is empty.  Works with or without z_lock
+ * held, but can only be consider a hint in the latter case.  Returns true
+ * if only "." and ".." remain and there's no work in progress.
+ */
+boolean_t
+zfs_dirempty(znode_t *dzp)
+{
+	return (dzp->z_phys->zp_size == 2 && dzp->z_dirlocks == 0);
+}
+
+int
+zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr)
+{
+	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
+	znode_t *xzp;
+	dmu_tx_t *tx;
+	int error;
+	zfs_fuid_info_t *fuidp = NULL;
+
+	*xvpp = NULL;
+
+	if (error = zfs_zaccess(zp, ACE_WRITE_NAMED_ATTRS, 0, B_FALSE, cr))
+		return (error);
+
+	tx = dmu_tx_create(zfsvfs->z_os);
+	dmu_tx_hold_bonus(tx, zp->z_id);
+	dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
+	if (IS_EPHEMERAL(crgetuid(cr)) || IS_EPHEMERAL(crgetgid(cr))) {
+		if (zfsvfs->z_fuid_obj == 0) {
+			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
+			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
+			    FUID_SIZE_ESTIMATE(zfsvfs));
+			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
+		} else {
+			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
+			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
+			    FUID_SIZE_ESTIMATE(zfsvfs));
+		}
+	}
+	error = dmu_tx_assign(tx, zfsvfs->z_assign);
+	if (error) {
+		if (error == ERESTART && zfsvfs->z_assign == TXG_NOWAIT)
+			dmu_tx_wait(tx);
+		dmu_tx_abort(tx);
+		return (error);
+	}
+	zfs_mknode(zp, vap, tx, cr, IS_XATTR, &xzp, 0, NULL, &fuidp);
+	ASSERT(xzp->z_phys->zp_parent == zp->z_id);
+	dmu_buf_will_dirty(zp->z_dbuf, tx);
+	zp->z_phys->zp_xattr = xzp->z_id;
+
+	(void) zfs_log_create(zfsvfs->z_log, tx, TX_MKXATTR, zp,
+	    xzp, "", NULL, fuidp, vap);
+	if (fuidp)
+		zfs_fuid_info_free(fuidp);
+	dmu_tx_commit(tx);
+
+	*xvpp = ZTOV(xzp);
+
+	return (0);
+}
+
+/*
+ * Return a znode for the extended attribute directory for zp.
+ * ** If the directory does not already exist, it is created **
+ *
+ *	IN:	zp	- znode to obtain attribute directory from
+ *		cr	- credentials of caller
+ *		flags	- flags from the VOP_LOOKUP call
+ *
+ *	OUT:	xzpp	- pointer to extended attribute znode
+ *
+ *	RETURN:	0 on success
+ *		error number on failure
+ */
+int
+zfs_get_xattrdir(znode_t *zp, vnode_t **xvpp, cred_t *cr, int flags)
+{
+	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
+	znode_t		*xzp;
+	zfs_dirlock_t	*dl;
+	vattr_t		va;
+	int		error;
+top:
+	error = zfs_dirent_lock(&dl, zp, "", &xzp, ZXATTR, NULL, NULL);
+	if (error)
+		return (error);
+
+	if (xzp != NULL) {
+		*xvpp = ZTOV(xzp);
+		zfs_dirent_unlock(dl);
+		return (0);
+	}
+
+	ASSERT(zp->z_phys->zp_xattr == 0);
+
+	if (!(flags & CREATE_XATTR_DIR)) {
+		zfs_dirent_unlock(dl);
+		return (ENOENT);
+	}
+
+	if (zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) {
+		zfs_dirent_unlock(dl);
+		return (EROFS);
+	}
+
+	/*
+	 * The ability to 'create' files in an attribute
+	 * directory comes from the write_xattr permission on the base file.
+	 *
+	 * The ability to 'search' an attribute directory requires
+	 * read_xattr permission on the base file.
+	 *
+	 * Once in a directory the ability to read/write attributes
+	 * is controlled by the permissions on the attribute file.
+	 */
+	va.va_mask = AT_TYPE | AT_MODE | AT_UID | AT_GID;
+	va.va_type = VDIR;
+	va.va_mode = S_IFDIR | S_ISVTX | 0777;
+	zfs_fuid_map_ids(zp, cr, &va.va_uid, &va.va_gid);
+
+	error = zfs_make_xattrdir(zp, &va, xvpp, cr);
+	zfs_dirent_unlock(dl);
+
+	if (error == ERESTART && zfsvfs->z_assign == TXG_NOWAIT) {
+		/* NB: we already did dmu_tx_wait() if necessary */
+		goto top;
+	}
+
+	return (error);
+}
+
+/*
+ * Decide whether it is okay to remove within a sticky directory.
+ *
+ * In sticky directories, write access is not sufficient;
+ * you can remove entries from a directory only if:
+ *
+ *	you own the directory,
+ *	you own the entry,
+ *	the entry is a plain file and you have write access,
+ *	or you are privileged (checked in secpolicy...).
+ *
+ * The function returns 0 if remove access is granted.
+ */
+int
+zfs_sticky_remove_access(znode_t *zdp, znode_t *zp, cred_t *cr)
+{
+	uid_t  		uid;
+	uid_t		downer;
+	uid_t		fowner;
+	zfsvfs_t	*zfsvfs = zdp->z_zfsvfs;
+
+	if (zdp->z_zfsvfs->z_assign >= TXG_INITIAL)	/* ZIL replay */
+		return (0);
+
+	if ((zdp->z_phys->zp_mode & S_ISVTX) == 0)
+		return (0);
+
+	downer = zfs_fuid_map_id(zfsvfs, zdp->z_phys->zp_uid, cr, ZFS_OWNER);
+	fowner = zfs_fuid_map_id(zfsvfs, zp->z_phys->zp_uid, cr, ZFS_OWNER);
+
+	if ((uid = crgetuid(cr)) == downer || uid == fowner ||
+	    (ZTOV(zp)->v_type == VREG &&
+	    zfs_zaccess(zp, ACE_WRITE_DATA, 0, B_FALSE, cr) == 0))
+		return (0);
+	else
+		return (secpolicy_vnode_remove(cr));
+}