Support for longnames for files/directories (Linux part)

This patch adds the ability for zfs to support file/dir name up to 1023
bytes. This number is chosen so we can support up to 255 4-byte
characters. This new feature is represented by the new feature flag
feature@longname.

A new dataset property "longname" is also introduced to toggle longname
support for each dataset individually. This property can be disabled,
even if it contains longname files. In such case, new file cannot be
created with longname but existing longname files can still be looked
up.

Note that, to my knowledge native Linux filesystems don't support name
longer than 255 bytes. So there might be programs not able to work with
longname.

Note that NFS server may needs to use exportfs_get_name to reconnect
dentries, and the buffer being passed is limit to NAME_MAX+1 (256). So
NFS may not work when longname is enabled.

Note, FreeBSD vfs layer imposes a limit of 255 name lengh, so even
though we add code to support it here, it won't actually work.

Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by: Chunwei Chen <[email protected]>
Closes #15921

10 files changed, 540 insertions, 1 deletions

diff --git a/tests/runfiles/linux.run b/tests/runfiles/linux.run
index 4e262affb..5534cd27f 100644
--- a/tests/runfiles/linux.run
+++ b/tests/runfiles/linux.run
@@ -143,6 +143,10 @@ pre =
 post =
 tags = ['functional', 'largest_pool']
 
+[tests/functional/longname:Linux]
+tests = ['longname_001_pos', 'longname_002_pos', 'longname_003_pos']
+tags = ['functional', 'longname']
+
 [tests/functional/mmap:Linux]
 tests = ['mmap_libaio_001_pos', 'mmap_sync_001_pos']
 tags = ['functional', 'mmap']
@@ -187,7 +191,7 @@ tests = ['renameat2_noreplace', 'renameat2_exchange', 'renameat2_whiteout']
 tags = ['functional', 'renameat2']
 
 [tests/functional/rsend:Linux]
-tests = ['send_realloc_dnode_size', 'send_encrypted_files']
+tests = ['send_realloc_dnode_size', 'send_encrypted_files', 'send-c_longname']
 tags = ['functional', 'rsend']
 
 [tests/functional/simd:Linux]
diff --git a/tests/zfs-tests/tests/Makefile.am b/tests/zfs-tests/tests/Makefile.am
index da6dc235c..206ee8ac1 100644
--- a/tests/zfs-tests/tests/Makefile.am
+++ b/tests/zfs-tests/tests/Makefile.am
@@ -1605,6 +1605,11 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/link_count/link_count_001.ksh \
 	functional/link_count/link_count_root_inode.ksh \
 	functional/link_count/setup.ksh \
+	functional/longname/cleanup.ksh \
+	functional/longname/longname_001_pos.ksh \
+	functional/longname/longname_002_pos.ksh \
+	functional/longname/longname_003_pos.ksh \
+	functional/longname/setup.ksh \
 	functional/log_spacemap/log_spacemap_import_logs.ksh \
 	functional/migration/cleanup.ksh \
 	functional/migration/migration_001_pos.ksh \
@@ -1938,6 +1943,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/rsend/rsend_031_pos.ksh \
 	functional/rsend/send-c_embedded_blocks.ksh \
 	functional/rsend/send-c_incremental.ksh \
+	functional/rsend/send-c_longname.ksh \
 	functional/rsend/send-c_lz4_disabled.ksh \
 	functional/rsend/send-c_mixed_compression.ksh \
 	functional/rsend/send-c_props.ksh \
diff --git a/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg b/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
index 50c1b7a9d..b5bc46dce 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
+++ b/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
@@ -110,5 +110,6 @@ if is_linux || is_freebsd; then
 	    "feature@vdev_zaps_v2"
 	    "feature@raidz_expansion"
 	    "feature@fast_dedup"
+	    "feature@longname"
 	)
 fi
diff --git a/tests/zfs-tests/tests/functional/longname/cleanup.ksh b/tests/zfs-tests/tests/functional/longname/cleanup.ksh
new file mode 100755
index 000000000..aac8062ec
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/cleanup.ksh
@@ -0,0 +1,34 @@
+#!/bin/ksh -p
+#
+# 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 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+default_cleanup
diff --git a/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh
new file mode 100755
index 000000000..b7010fe0f
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh
@@ -0,0 +1,132 @@
+#! /bin/ksh -p
+#
+# 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 (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Verify the support for long filenames.
+#
+# STRATEGY:
+# 0.  On a fresh dataset ensure property "longname" is enabled by default.
+# 1.  Disable the longname.
+# 2.  Try to create a filename whose length is > 256 bytes. This should fail.
+# 3.  Enable "longname" property on the dataset.
+# 4.  Try to create files and dirs whose names are > 256 bytes.
+# 5.  Ensure that "ls" is able to list the file.
+# 6.  Ensure stat(1) is able to stat the file/directory.
+# 7.  Try to rename the files and directories
+# 8.  Try to delete the files and directories
+
+verify_runnable "global"
+
+WORKDIR=$TESTDIR/workdir
+MOVEDIR=$TESTDIR/movedir/level2/level3/level4/level5/level6
+
+function cleanup
+{
+        log_must rm -rf $WORKDIR
+        log_must rm -rf $TESTDIR/movedir
+}
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+LONGPNAME="mypipe-$LONGNAME"
+LONGCNAME="char_dev-$LONGNAME"
+LONGLNAME="link-$LONGNAME"
+LONGNAME_255=$(printf 'a%.0s' {1..255})
+LONGNAME_1023=$(printf 'a%.0s' {1..1023})
+
+
+log_assert "Check longname support for directories/files"
+
+log_onexit cleanup
+
+log_must mkdir $WORKDIR
+log_must mkdir -p $MOVEDIR
+
+# Disable longname support
+log_must zfs set longname=off $TESTPOOL/$TESTFS
+
+#Ensure a file of length 255bytes can be created
+log_must touch $WORKDIR/$LONGNAME_255
+
+#Where as file of length 256bytes should fail
+log_mustnot touch $WORKDIR/${LONGNAME_255}b
+
+# Try to create a file with long name with property "longname=off"
+log_mustnot touch $WORKDIR/$LONGFNAME
+log_mustnot mkdir $WORKDIR/$LONGDNAME
+
+# Enable longname support
+log_must zfs set longname=on $TESTPOOL/$TESTFS
+
+# Retry the longname creates and that should succeed
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Should be able to create a file with name of 1023 chars
+log_must touch $WORKDIR/$LONGNAME_1023
+
+# And names longer that 1023 should fail
+log_mustnot touch $WORKDIR/${LONGNAME_1023}b
+
+# Ensure the longnamed dir/file can be listed.
+name=$(ls $WORKDIR/$LONGFNAME)
+if [[ "${name}" != "$WORKDIR/$LONGFNAME" ]]; then
+        log_fail "Unable to list: $WORKDIR/$LONGFNAME ret:$name"
+fi
+
+name=$(ls -d $WORKDIR/$LONGDNAME)
+if [[ "${name}" != "$WORKDIR/$LONGDNAME" ]]; then
+        log_fail "Unable to list: $WORKDIR/$LONGDNAME ret:$name"
+fi
+
+# Ensure stat works
+log_must stat $WORKDIR/$LONGFNAME
+log_must stat $WORKDIR/$LONGDNAME
+
+# Ensure softlinks can be created from a longname to
+# another longnamed file.
+log_must ln -s $WORKDIR/$LONGFNAME $WORKDIR/$LONGLNAME
+
+# Ensure a longnamed pipe and character device file
+# can be created
+log_must mknod $WORKDIR/$LONGPNAME p
+log_must mknod $WORKDIR/$LONGCNAME c 92 1
+
+# Ensure we can rename the longname file
+log_must mv $WORKDIR/$LONGFNAME $WORKDIR/file2
+
+# Delete the long named dir/file
+log_must rmdir $WORKDIR/$LONGDNAME
+log_must rm $WORKDIR/file2
+log_must rm $WORKDIR/$LONGPNAME
+log_must rm $WORKDIR/$LONGCNAME
+log_must rm $WORKDIR/$LONGLNAME
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh
new file mode 100755
index 000000000..dd2acabb3
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh
@@ -0,0 +1,115 @@
+#! /bin/ksh -p
+#
+# 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 (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Check if longname feature is disabled by default and can be enabled.
+#
+# STRATEGY:
+# 1. Create a zpool with longname feature disabled
+# 2. Attempt to enable 'longname' property should fail.
+# 3. Attempt to create a longnamed (>255) file should fail.
+# 4. Enable the feature@longname
+# 5. Enable 'longname' property on the dataset.
+# 6. Should be able to create long named files and directories.
+# 7. Should be able to disable longname property.
+# 8. This should disallow creating new longnamed file/dirs. But, should be
+#    able to access existing longnamed files/dirs.
+verify_runnable "global"
+
+function cleanup
+{
+        log_must rm -rf $WORKDIR
+        poolexists $TESTPOOL && zpool destroy $TESTPOOL
+}
+
+log_assert "Check feature@longname and 'longname' dataset propery work correctly"
+
+log_onexit cleanup
+
+log_must zpool destroy $TESTPOOL
+
+log_must zpool create -o feature@longname=disabled $TESTPOOL $DISKS
+
+log_must zfs create $TESTPOOL/$TESTFS2
+
+log_must zfs set mountpoint=$TESTDIR2 $TESTPOOL/$TESTFS2
+
+log_mustnot zfs set longname=on $TESTPOOL/$TESTFS2
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+SHORTDNAME="dir-short"
+SHORTFNAME="file-short"
+WORKDIR=$TESTDIR2/workdir
+
+log_must mkdir $WORKDIR
+log_mustnot touch $WORKDIR/$LONGFNAME
+log_mustnot mkdir $WORKDIR/$LONGDNAME
+
+log_must zpool set feature@longname=enabled $TESTPOOL
+log_must zfs set longname=on $TESTPOOL/$TESTFS2
+
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Ensure the above changes are synced out.
+log_must zpool sync $TESTPOOL
+
+# Ensure that the feature is activated once longnamed files are created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+
+if [[ "$state" != "active" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+# Set longname=off.
+log_must zfs set longname=off $TESTPOOL/$TESTFS2
+
+# Ensure no new file/directory with longnames can be created or can be renamed
+# to.
+log_mustnot mkdir $WORKDIR/${LONGDNAME}.1
+log_mustnot touch $WORKDIR/${LONGFNAME}.1
+log_must mkdir $WORKDIR/$SHORTDNAME
+log_mustnot mv $WORKDIR/$SHORTDNAME $WORKDIR/${LONGDNAME}.1
+log_must touch $WORKDIR/$SHORTFNAME
+log_mustnot mv $WORKDIR/$SHORTFNAME $WORKDIR/${LONGFNAME}.1
+
+#Cleanup shortnames
+log_must rmdir $WORKDIR/$SHORTDNAME
+log_must rm $WORKDIR/$SHORTFNAME
+
+# But, should be able to stat and rename existing files
+log_must stat $WORKDIR/$LONGDNAME
+log_must stat $WORKDIR/$LONGFNAME
+log_must mv $WORKDIR/$LONGDNAME $WORKDIR/$SHORTDNAME
+log_must mv $WORKDIR/$LONGFNAME $WORKDIR/$SHORTFNAME
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh
new file mode 100755
index 000000000..f684b5143
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh
@@ -0,0 +1,113 @@
+#! /bin/ksh -p
+#
+# 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 (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Check if longnames are handled correctly by ZIL replay and feature is activated.
+#
+# STRATEGY:
+# 1. Create a zpool with longname feature disabled
+# 2. Enable the feature@longname
+# 3. Enable 'longname' property on the dataset.
+# 4. Freeze the zpool
+# 5. Create a longname
+# 6. Export and import the zpool.
+# 7. Replaying of longname create should activate the feature@longname
+verify_runnable "global"
+
+function cleanup
+{
+	log_must rm -rf $WORKDIR
+	poolexists $TESTPOOL && zpool destroy $TESTPOOL
+}
+
+log_assert "Check feature@longname and 'longname' dataset propery work correctly"
+
+log_onexit cleanup
+
+poolexists $TESTPOOL && zpool destroy $TESTPOOL
+
+log_must zpool create -o feature@longname=disabled $TESTPOOL $DISKS
+
+log_must zfs create $TESTPOOL/$TESTFS
+
+log_must zfs set mountpoint=$TESTDIR $TESTPOOL/$TESTFS
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+SHORTDNAME="dir-short"
+SHORTFNAME="file-short"
+WORKDIR=$TESTDIR/workdir
+
+log_must mkdir $WORKDIR
+
+log_must zpool set feature@longname=enabled $TESTPOOL
+log_must zfs set longname=on $TESTPOOL/$TESTFS
+
+# Ensure that the feature is NOT activated yet as no longnamed file is created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+
+if [[ "$state" != "enabled" ]]; then
+	log_fail "feature@longname has state $state (expected enabled)"
+fi
+
+#
+# This dd command works around an issue where ZIL records aren't created
+# after freezing the pool unless a ZIL header already exists. Create a file
+# synchronously to force ZFS to write one out.
+#
+log_must dd if=/dev/zero of=/$WORKDIR/sync conv=fdatasync,fsync bs=1 count=1
+
+log_must zpool freeze $TESTPOOL
+
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Export and re-import the zpool
+log_must zpool export $TESTPOOL
+log_must zpool import $TESTPOOL
+
+# Ensure that the feature is activated once longnamed files are created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+if [[ "$state" != "active" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+# Destroying the dataset where the feature is activated should put the feature
+# back to 'enabled' state
+log_must zfs destroy -r $TESTPOOL/$TESTFS
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+if [[ "$state" != "enabled" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/setup.ksh b/tests/zfs-tests/tests/functional/longname/setup.ksh
new file mode 100755
index 000000000..3f6759469
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/setup.ksh
@@ -0,0 +1,35 @@
+#!/bin/ksh -p
+#
+# 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 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+DISK=${DISKS%% *}
+default_setup $DISK
diff --git a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
index 8f2222dce..b4fcdd7bb 100644
--- a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
+++ b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
@@ -713,6 +713,7 @@ function stream_has_features
 	feature[resuming]="100000"
 	feature[redacted]="200000"
 	feature[compressed]="400000"
+	feature[longname]="10000000"
 
 	typeset flag known derived=0
 	for flag in "$@"; do
diff --git a/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh b/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh
new file mode 100755
index 000000000..3f7edc681
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh
@@ -0,0 +1,98 @@
+#!/bin/ksh -p
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/tests/functional/rsend/rsend.kshlib
+. $STF_SUITE/include/properties.shlib
+
+#
+# Description:
+# Verify that longname featureflag is present in the stream.
+#
+# Strategy:
+# 1. Create a filesystem with longnamed files/directories.
+# 2. Verify that the sendstream has the longname featureflag is present in the
+#    send stream.
+# 3. Verify the created streams can be received correctly.
+# 4. Verify that the longnamed files/directories are present in the received
+#    filesystem.
+#
+
+verify_runnable "both"
+
+log_assert "Verify that longnames are handled correctly in send stream."
+log_onexit cleanup_pool $POOL $POOL2 $POOL3
+
+typeset sendfs=$POOL/sendfs
+typeset recvfs=$POOL2/recvfs
+typeset recvfs3=$POOL3/recvfs
+typeset stream=$BACKDIR/stream
+typeset dump=$BACKDIR/dump
+
+log_must zfs create -o longname=on $sendfs
+typeset dir=$(get_prop mountpoint $sendfs)
+
+# Create a longnamed dir and a file in the send dataset
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+log_must mkdir $dir/$LONGDNAME
+log_must touch $dir/$LONGFNAME
+
+# When POOL3 is created by rsend.kshlib feature@longname is 'enabled'.
+# Recreate the POOL3 with feature@longname disabled.
+datasetexists $POOL3 && log_must zpool destroy $POOL3
+log_must zpool create -o feature@longname=disabled $POOL3 $DISK3
+
+# Generate the streams and zstreamdump output.
+log_must zfs snapshot $sendfs@now
+log_must eval "zfs send -p $sendfs@now >$stream"
+log_must eval "zstream dump -v <$stream >$dump"
+log_must eval "zfs recv $recvfs <$stream"
+cmp_ds_cont $sendfs $recvfs
+log_must stream_has_features $stream longname
+
+# Ensure the the receiving pool has feature@longname activated after receiving.
+feat_val=$(zpool get -H -o value feature@longname $POOL2)
+log_note "Zpool $POOL2 feature@longname=$feat_val"
+if [[ "$feat_val" != "active" ]]; then
+	log_fail "pool $POOL2 feature@longname=$feat_val (expected 'active')"
+fi
+
+# Receiving of the stream on $POOL3 should fail as longname is not enabled
+log_mustnot eval "zfs recv $recvfs3 <$stream"
+
+# Enable feature@longname and retry the receiving the stream.
+# It should succeed this time.
+log_must eval "zpool set feature@longname=enabled $POOL3"
+log_must eval "zfs recv $recvfs3 <$stream"
+
+log_must zfs get longname $recvfs3
+prop_val=$(zfs get -H -o value longname $recvfs3)
+log_note "dataset $recvfs3 has longname=$prop_val"
+if [[ "$prop_val" != "on" ]]; then
+	log_fail "$recvfs3 has longname=$prop_val (expected 'on')"
+fi
+
+#
+# TODO:
+# - Add a testcase to cover the case where send-stream does not contain
+#   properties (generated without "-p").
+#   In this case the target dataset would have longname files/directories which
+#   cannot be accessed if the dataset property 'longname=off'.
+#
+
+log_pass "Longnames are handled correctly in send/recv"