Enforce "-F" flag on resuming recv of full/newfs on existing dataset

When receiving full/newfs on existing dataset, then it should be done
with "-F" flag. Its enforced for initial receive in checks done in
zfs_receive_one function of libzfs. Similarly, on resuming full/newfs
recv on existing dataset, it should be done with "-F" flag.

When dataset doesn't exist, then full/new recv is done on newly created
dataset and it's marked INCONSISTENT. But when receiving on existing
dataset, recv is first done on %recv and its marked INCONSISTENT.
Existing dataset is not marked INCONSISTENT. Resume of full/newfs
receive with dataset not INCONSISTENT indicates that its resuming newfs
on existing dataset. So, enforce "-F" flag in this case.

Also return an error from dmu_recv_resume_begin_check() in zfs kernel,
when its resuming full/newfs recv without force.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chunwei Chen <david.chen@nutanix.com>
Signed-off-by: Jitendra Patidar <jitendra.patidar@nutanix.com>
Closes #13856
Closes #13857

tests/zfs-tests/tests/Makefile.am

@@ -1780,6 +1780,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/rsend/rsend_027_pos.ksh \
 	functional/rsend/rsend_028_neg.ksh \
 	functional/rsend/rsend_029_neg.ksh \
+	functional/rsend/rsend_030_pos.ksh \
 	functional/rsend/send-c_embedded_blocks.ksh \
 	functional/rsend/send-c_incremental.ksh \
 	functional/rsend/send-c_lz4_disabled.ksh \

tests/zfs-tests/tests/functional/rsend/rsend_030_pos.ksh

@@ -0,0 +1,66 @@
+#!/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) 2022 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/tests/functional/rsend/rsend.kshlib
+
+#
+# Description:
+# Verify resumability of full ZFS send/receive on existing dataset
+#
+# Strategy:
+# 1. Start a full ZFS send with redirect output to a file
+# 2. Mess up the contents of the stream state file on disk
+# 3. Try ZFS receive, which should fail with a checksum mismatch error
+# 4. ZFS send to the stream state file again using the receive_resume_token
+# 5. Verify ZFS receive without "-F" option (force recvflag) fails.
+# 6. Verify ZFS receive with "-F" option completes successfully.
+# 7. Repeat steps on an incremental ZFS send. It should complete
+#    successfully without "-F" option.
+#
+
+verify_runnable "both"
+
+sendfs=$POOL/sendfs
+recvfs=$POOL2/recvfs
+streamfs=$POOL/stream
+
+log_assert "Verify resumability of full ZFS send/receive on existing dataset"
+log_onexit resume_cleanup $sendfs $streamfs
+
+test_fs_setup $sendfs $recvfs $streamfs
+
+# Full send/recv on existing dataset
+log_must zfs create -o readonly=on $recvfs
+log_must eval "zfs send -c -v $sendfs@a >/$streamfs/1"
+mess_send_file /$streamfs/1
+log_mustnot eval "zfs recv -suvF $recvfs </$streamfs/1"
+token=$(get_prop receive_resume_token $recvfs)
+log_must eval "zfs send -t $token  >/$streamfs/2"
+log_mustnot eval "zfs recv -suv $recvfs </$streamfs/2"
+log_must eval "zfs recv -suvF $recvfs </$streamfs/2"
+file_check $sendfs $recvfs
+
+# Incremental send/recv
+log_must eval "zfs send -c -v -i @a $sendfs@b >/$streamfs/3"
+mess_send_file /$streamfs/3
+log_mustnot eval "zfs recv -suvF $recvfs </$streamfs/3"
+token=$(get_prop receive_resume_token $recvfs)
+log_must eval "zfs send -t $token  >/$streamfs/4"
+log_must eval "zfs recv -suv $recvfs </$streamfs/4"
+file_check $sendfs $recvfs
+
+log_pass "Verify resumability of full ZFS send/receive on existing dataset"