ZTS: Test for clone, mmap and write for block cloning

For block cloning, if we mmap the cloned file and write from the
map into the file, it triggers a panic in dbuf_redirty() on Linux.

The same scenario causes data corruption on FreeBSD. Both these
issues are fixed under PR#15656 and PR#15665.

It would be good to add a test for this scenario in ZTS. The test
program and issue was produced by @robn.

Reviewed-by: Pawel Jakub Dawidek <pawel@dawidek.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #15717

tests/runfiles/common.run

@@ -79,7 +79,7 @@ tests = ['block_cloning_copyfilerange', 'block_cloning_copyfilerange_partial',
     'block_cloning_cross_enc_dataset',
     'block_cloning_copyfilerange_fallback_same_txg',
     'block_cloning_replay', 'block_cloning_replay_encrypted',
-    'block_cloning_lwb_buffer_overflow']
+    'block_cloning_lwb_buffer_overflow', 'block_cloning_clone_mmap_write']
 tags = ['functional', 'block_cloning']
 
 [tests/functional/bootfs]

tests/test-runner/bin/zts-report.py.in

@@ -287,6 +287,8 @@ elif sys.platform.startswith('linux'):
         'bclone/bclone_samefs_data': ['SKIP', cfr_reason],
         'bclone/bclone_samefs_embedded': ['SKIP', cfr_reason],
         'bclone/bclone_samefs_hole': ['SKIP', cfr_reason],
+        'block_cloning/block_cloning_clone_mmap_write':
+            ['SKIP', cfr_reason],
         'block_cloning/block_cloning_copyfilerange':
             ['SKIP', cfr_reason],
         'block_cloning/block_cloning_copyfilerange_cross_dataset':

tests/zfs-tests/cmd/.gitignore

@@ -2,6 +2,7 @@
 /btree_test
 /chg_usr_exec
 /clonefile
+/clone_mmap_write
 /devname2devid
 /dir_rd_update
 /draid

tests/zfs-tests/cmd/Makefile.am

@@ -3,6 +3,7 @@ scripts_zfs_tests_bindir = $(datadir)/$(PACKAGE)/zfs-tests/bin
 
 scripts_zfs_tests_bin_PROGRAMS  = %D%/chg_usr_exec
 scripts_zfs_tests_bin_PROGRAMS += %D%/clonefile
+scripts_zfs_tests_bin_PROGRAMS += %D%/clone_mmap_write
 scripts_zfs_tests_bin_PROGRAMS += %D%/cp_files
 scripts_zfs_tests_bin_PROGRAMS += %D%/ctime
 scripts_zfs_tests_bin_PROGRAMS += %D%/dir_rd_update

tests/zfs-tests/cmd/clone_mmap_write.c

@@ -0,0 +1,123 @@
+/*
+ * 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 https://opensource.org/licenses/CDDL-1.0.
+ * 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
+ */
+
+/*
+ * This program clones the file, mmap it, and writes from the map into
+ * file. This scenario triggers a panic on Linux in dbuf_redirty(),
+ * which is fixed under PR#15656. On FreeBSD, the same test causes data
+ * corruption, which is fixed by PR#15665.
+ *
+ * It would be good to test for this scenario in ZTS. This program and
+ * issue was initially produced by @robn.
+ */
+#ifndef _GNU_SOURCE
+#define	_GNU_SOURCE
+#endif
+
+#include <fcntl.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#ifdef __FreeBSD__
+#define	loff_t	off_t
+#endif
+
+ssize_t
+copy_file_range(int, loff_t *, int, loff_t *, size_t, unsigned int)
+    __attribute__((weak));
+
+static int
+open_file(const char *source)
+{
+	int fd;
+	if ((fd = open(source, O_RDWR | O_APPEND)) < 0) {
+		(void) fprintf(stderr, "Error opening %s\n", source);
+		exit(1);
+	}
+	sync();
+	return (fd);
+}
+
+static int
+clone_file(int sfd, long long size, const char *dest)
+{
+	int dfd;
+
+	if ((dfd = open(dest, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) < 0) {
+		(void) fprintf(stderr, "Error opening %s\n", dest);
+		exit(1);
+	}
+
+	if (copy_file_range(sfd, 0, dfd, 0, size, 0) < 0) {
+		(void) fprintf(stderr, "copy_file_range failed\n");
+		exit(1);
+	}
+
+	return (dfd);
+}
+
+static void *
+map_file(int fd, long long size)
+{
+	void *p = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+	if (p == MAP_FAILED) {
+		(void) fprintf(stderr, "mmap failed\n");
+		exit(1);
+	}
+
+	return (p);
+}
+
+static void
+map_write(void *p, int fd)
+{
+	if (pwrite(fd, p, 1024*128, 0) < 0) {
+		(void) fprintf(stderr, "write failed\n");
+		exit(1);
+	}
+}
+
+int
+main(int argc, char **argv)
+{
+	int sfd, dfd;
+	void *p;
+	struct stat sb;
+	if (argc != 3) {
+		(void) printf("usage: %s <input source file> "
+		    "<clone destination file>\n", argv[0]);
+		exit(1);
+	}
+	sfd = open_file(argv[1]);
+	if (fstat(sfd, &sb) == -1) {
+		(void) fprintf(stderr, "fstat failed\n");
+		exit(1);
+	}
+	dfd = clone_file(sfd, sb.st_size, argv[2]);
+	p = map_file(dfd, sb.st_size);
+	map_write(p, dfd);
+	return (0);
+}

tests/zfs-tests/include/commands.cfg

@@ -185,6 +185,7 @@ export ZFSTEST_FILES='badsend
     btree_test
     chg_usr_exec
     clonefile
+    clone_mmap_write
     devname2devid
     dir_rd_update
     draid

tests/zfs-tests/tests/Makefile.am

@@ -461,6 +461,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/bclone/setup.ksh \
 	functional/block_cloning/cleanup.ksh \
 	functional/block_cloning/setup.ksh \
+	functional/block_cloning/block_cloning_clone_mmap_write.ksh \
 	functional/block_cloning/block_cloning_copyfilerange_cross_dataset.ksh \
 	functional/block_cloning/block_cloning_copyfilerange_fallback.ksh \
 	functional/block_cloning/block_cloning_copyfilerange_fallback_same_txg.ksh \

tests/zfs-tests/tests/functional/block_cloning/block_cloning_clone_mmap_write.ksh

@@ -0,0 +1,79 @@
+#!/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 https://opensource.org/licenses/CDDL-1.0.
+# 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
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/block_cloning/block_cloning.kshlib
+
+#
+# DESCRIPTION:
+#	A PANIC is triggered in dbuf_redirty() if we clone a file, mmap it
+#	and write from the map into the file. PR#15656 fixes this scenario.
+#	This scenario also causes data corruption on FreeBSD, which is fixed
+#	by PR#15665.
+#
+# STRATEGY:
+#	1. Create a pool
+#	2. Create a test file 
+#	3. Clone, mmap and write to the file using clone_mmap_write
+#	5. Synchronize cached writes
+#	6. Verfiy data is correctly written to the disk
+#
+
+verify_runnable "global"
+
+if is_linux && [[ $(linux_version) -lt $(linux_version "4.5") ]]; then
+  log_unsupported "copy_file_range not available before Linux 4.5"
+fi
+
+VDIR=$TEST_BASE_DIR/disk-bclone
+VDEV="$VDIR/a"
+
+function cleanup
+{
+	datasetexists $TESTPOOL && destroy_pool $TESTPOOL
+	rm -rf $VDIR
+}
+
+log_onexit cleanup
+
+log_assert "Test for clone, mmap and write scenario"
+
+log_must rm -rf $VDIR
+log_must mkdir -p $VDIR
+log_must truncate -s 1G $VDEV
+
+log_must zpool create -o feature@block_cloning=enabled $TESTPOOL $VDEV
+log_must zfs create $TESTPOOL/$TESTFS
+
+log_must dd if=/dev/urandom of=/$TESTPOOL/$TESTFS/file bs=1M count=512
+log_must clone_mmap_write /$TESTPOOL/$TESTFS/file /$TESTPOOL/$TESTFS/clone
+
+sync_pool $TESTPOOL
+log_must sync
+
+log_must have_same_content /$TESTPOOL/$TESTFS/file /$TESTPOOL/$TESTFS/clone
+blocks=$(get_same_blocks $TESTPOOL/$TESTFS file $TESTPOOL/$TESTFS clone)
+# FreeBSD's seq(1) leaves a trailing space, remove it with sed(1).
+log_must [ "$blocks" = "$(seq -s " " 1 4095 | sed 's/ $//')" ]
+
+log_pass "Clone, mmap and write does not cause data corruption or " \
+	"trigger panic"