Fix cloning into mmaped and cached file.

If the destination file is mmaped and the mmaped region was already
read, so it is cached, we need to update mmaped pages after successful
clone using update_pages().

Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Pointed out by: Ka Ho Ng <[email protected]>
Signed-off-by: Pawel Jakub Dawidek <[email protected]>
Closes #15772 

1 files changed, 146 insertions, 0 deletions

diff --git a/tests/zfs-tests/cmd/clone_mmap_cached.c b/tests/zfs-tests/cmd/clone_mmap_cached.c
new file mode 100644
index 000000000..c1cdf796c
--- /dev/null
+++ b/tests/zfs-tests/cmd/clone_mmap_cached.c
@@ -0,0 +1,146 @@
+/*
+ * 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
+ */
+
+/*
+ * Copyright (c) 2024 by Pawel Jakub Dawidek
+ */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.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 void *
+mmap_file(int fd, size_t size)
+{
+	void *p;
+
+	p = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+	if (p == MAP_FAILED) {
+		(void) fprintf(stderr, "mmap failed: %s\n", strerror(errno));
+		exit(2);
+	}
+
+	return (p);
+}
+
+static void
+usage(const char *progname)
+{
+
+	/*
+	 * -i cache input before copy_file_range(2).
+	 * -o cache input before copy_file_range(2).
+	 */
+	(void) fprintf(stderr, "usage: %s [-io] <input> <output>\n", progname);
+	exit(3);
+}
+
+int
+main(int argc, char *argv[])
+{
+	int dfd, sfd;
+	size_t dsize, ssize;
+	void *dmem, *smem, *ptr;
+	off_t doff, soff;
+	struct stat sb;
+	bool cache_input, cache_output;
+	const char *progname;
+	int c;
+
+	progname = argv[0];
+	cache_input = cache_output = false;
+
+	while ((c = getopt(argc, argv, "io")) != -1) {
+		switch (c) {
+		case 'i':
+			cache_input = true;
+			break;
+		case 'o':
+			cache_output = true;
+			break;
+		default:
+			usage(progname);
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if (argc != 2) {
+		usage(progname);
+	}
+
+	sfd = open(argv[0], O_RDONLY);
+	if (fstat(sfd, &sb) == -1) {
+		(void) fprintf(stderr, "fstat failed: %s\n", strerror(errno));
+		exit(2);
+	}
+	ssize = sb.st_size;
+	smem = mmap_file(sfd, ssize);
+
+	dfd = open(argv[1], O_RDWR);
+	if (fstat(dfd, &sb) == -1) {
+		(void) fprintf(stderr, "fstat failed: %s\n", strerror(errno));
+		exit(2);
+	}
+	dsize = sb.st_size;
+	dmem = mmap_file(dfd, dsize);
+
+	/*
+	 * Hopefully it won't be compiled out.
+	 */
+	if (cache_input) {
+		ptr = malloc(ssize);
+		assert(ptr != NULL);
+		memcpy(ptr, smem, ssize);
+		free(ptr);
+	}
+	if (cache_output) {
+		ptr = malloc(ssize);
+		assert(ptr != NULL);
+		memcpy(ptr, dmem, dsize);
+		free(ptr);
+	}
+
+	soff = doff = 0;
+	if (copy_file_range(sfd, &soff, dfd, &doff, ssize, 0) < 0) {
+		(void) fprintf(stderr, "copy_file_range failed: %s\n",
+		    strerror(errno));
+		exit(2);
+	}
+
+	exit(memcmp(smem, dmem, ssize) == 0 ? 0 : 1);
+}