zdtm: Add a test to check if we can C/R ghost files with no parent dirs.

This is test that triggers a bug with ghost files, that was resolved in
patch "Don't fail if ghost file has no parent dirs".
Signed-off-by: Vitaly Ostrosablin <vostrosablin@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/zdtm/static/Makefile

@@ -202,6 +202,7 @@ TST_NOFILE	:=				\
 		pipe03				\
 		netns_sub			\
 		netns_sub_veth			\
+		unlink_multiple_largefiles	\
 #		jobctl00			\
 
 include ../Makefile.inc

test/zdtm/static/unlink_multiple_largefiles.c

+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <limits.h>
+
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+#include <linux/fiemap.h>
+#include "zdtmtst.h"
+
+
+#define FSIZE 0x3B600000ULL
+#define NFILES 10
+#define BUFSIZE (1<<20)
+
+const char *test_doc = "C/R of ten big (951MiB) unlinked files in root dir";
+const char *test_author = "Vitaly Ostrosablin <vostrosablin@virtuozzo.com>";
+
+void create_check_pattern(char *buf, size_t count, unsigned char seed)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		buf[i] = seed++;
+}
+
+struct fiemap *read_fiemap(int fd)
+{
+	test_msg("Obtaining fiemap for fd %d\n", fd);
+	struct fiemap *fiemap;
+	int extents_size;
+
+	fiemap = malloc(sizeof(struct fiemap));
+	if (fiemap == NULL) {
+		pr_perror("Cannot allocate fiemap");
+		return NULL;
+	}
+	memset(fiemap, 0, sizeof(struct fiemap));
+
+	fiemap->fm_length = FIEMAP_MAX_OFFSET;
+	fiemap->fm_start = 0;
+	fiemap->fm_flags = 0;
+	fiemap->fm_extent_count = 0;
+
+	if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
+		pr_perror("FIEMAP ioctl failed");
+		return NULL;
+	}
+
+	extents_size = sizeof(struct fiemap_extent) * fiemap->fm_mapped_extents;
+
+	fiemap = realloc(fiemap,sizeof(struct fiemap) + extents_size);
+	if (fiemap == NULL) {
+		pr_perror("Cannot resize fiemap");
+		return NULL;
+	}
+	memset(fiemap->fm_extents, 0, extents_size);
+
+	fiemap->fm_extent_count = fiemap->fm_mapped_extents;
+	fiemap->fm_mapped_extents = 0;
+
+	if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
+		pr_perror("fiemap ioctl() failed");
+		return NULL;
+	}
+	test_msg("Debugkillme: %x\n", fiemap->fm_mapped_extents);
+
+	return fiemap;
+}
+
+void check_extent_map(struct fiemap *map)
+{
+	int i;
+	unsigned long long datasize = 0;
+	unsigned long long holesize = 0;
+
+	test_msg("Verifying extent map...\n");
+
+	for (i = 0; i < map->fm_mapped_extents; i++) {
+		test_msg("Extent %d, start %llx, length %llx\n",
+			i,
+			map->fm_extents[i].fe_logical,
+			map->fm_extents[i].fe_length);
+
+		if (i == 0)
+			holesize = map->fm_extents[i].fe_logical;
+		datasize += map->fm_extents[i].fe_length;
+	}
+	if (holesize != FSIZE) {
+		pr_err("Unexpected hole size %llx != %llx\n", holesize,
+				(unsigned long long) FSIZE);
+		exit(1);
+	}
+	if (datasize != BUFSIZE) {
+		pr_err("Unexpected data size %llx != %llx\n", datasize,
+				(unsigned long long) BUFSIZE);
+		exit(1);
+	}
+}
+
+void compare_file_content(int fildes, int seed)
+{
+	char ebuf[BUFSIZE];
+	char rbuf[BUFSIZE];
+	char linkpath[PATH_MAX];
+	int fd;
+	struct fiemap *fiemap;
+
+	ssprintf(linkpath, "/proc/self/fd/%d", fildes);
+
+	fd = open(linkpath, O_RDONLY | O_LARGEFILE);
+	if (fd < 0) {
+		pr_perror("Cannot open unlinked file %s", linkpath);
+		exit(1);
+	}
+
+	memset(ebuf, 0, BUFSIZE);
+
+	fiemap = read_fiemap(fd);
+	check_extent_map(fiemap);
+	free(fiemap);
+
+	lseek64(fd, FSIZE, SEEK_SET);
+
+	create_check_pattern(ebuf, BUFSIZE, seed);
+
+	if (read(fd, rbuf, BUFSIZE) != BUFSIZE) {
+		pr_perror("Cannot read %i bytes from file", BUFSIZE);
+		goto failed;
+	}
+
+	if (memcmp(&ebuf, &rbuf, BUFSIZE)) {
+		pr_err("Control Block: Data mismatch detected\n");
+		goto failed;
+	}
+
+	close(fd);
+	return;
+failed:
+	close(fd);
+	exit(1);
+}
+
+void read_proc_fd_link(int fd, char *buf)
+{
+	ssize_t res;
+	char linkpath[PATH_MAX];
+
+	ssprintf(linkpath, "/proc/%d/fd/%d", getpid(), fd);
+
+	res = readlink(linkpath, buf, PATH_MAX - 1);
+	buf[res] = 0;
+	if (res < 0) {
+		pr_perror("Cannot read fd symlink %s", linkpath);
+		exit(1);
+	}
+}
+
+int create_unlinked_file(int fileno)
+{
+	int fd;
+	char buf[BUFSIZE];
+	char fnm[PATH_MAX];
+
+	ssprintf(fnm, "/unlinked%d", fileno);
+	fd = open(fnm, O_WRONLY | O_CREAT | O_TRUNC | O_LARGEFILE, 0644);
+	if (fd < 0) {
+		pr_perror("Cannot create file %s", fnm);
+		exit(1);
+	}
+	test_msg("Created file: %s, fd %d\n", fnm, fd);
+
+	if (lseek64(fd, FSIZE, SEEK_SET) < 0) {
+		pr_perror("Cannot seek to offset %llx", FSIZE);
+		goto failed;
+	}
+	test_msg("File positioning done, offset=%llx\n", FSIZE);
+
+	create_check_pattern(&buf[0], BUFSIZE, fileno);
+	if (write(fd, buf, BUFSIZE) != BUFSIZE) {
+		pr_perror("Cannot write %i bytes to file", BUFSIZE);
+		goto failed;
+	}
+	test_msg("%i bytes written to file\n", BUFSIZE);
+
+	if (unlink(fnm) < 0) {
+		pr_perror("Cannot unlink file %s", fnm);
+		goto failed;
+	}
+	test_msg("File %s is unlinked\n", fnm);
+
+	return fd;
+failed:
+	unlink(fnm);
+	close(fd);
+	return -1;
+}
+
+int main(int argc, char **argv)
+{
+	int fd[NFILES] = {0};
+	char links[NFILES][PATH_MAX];
+	char link[PATH_MAX];
+	int count = 0;
+	int tempfd;
+
+	test_init(argc, argv);
+
+	/* We need to create 10 unlinked files, each is around 1GB in size */
+	for (count = 0; count < NFILES; count++) {
+
+		test_msg("Creating unlinked file %d/%d\n", count + 1, NFILES);
+		tempfd = create_unlinked_file(count);
+
+		if (tempfd < 0) {
+			pr_err("Cannot create unlinked file %d/%d\n",
+				  count + 1, NFILES);
+			return 1;
+		}
+
+		memset(&links[count][0], 0, PATH_MAX);
+		read_proc_fd_link(tempfd, &links[count][0]);
+
+		fd[count] = tempfd;
+	}
+	test_msg("Created %d unlinked files\n", NFILES);
+
+	test_daemon();
+	test_msg("Test daemonized, PID %d\n", getpid());
+	test_waitsig();
+
+	test_msg("PID %d resumed, doing final checks...\n", getpid());
+
+	for (count = 0; count < NFILES; count++) {
+		test_msg("Processing fd #%d (%d)\n", count, fd[count]);
+
+		test_msg("Checking symlink consistency...\n");
+		memset(&link[0], 0, PATH_MAX);
+		read_proc_fd_link(fd[count], &link[0]);
+
+		if (strcmp(&links[count][0], &link[0])) {
+			pr_err("Symlink target %s has changed to %s\n",
+				  links[count], link);
+			return 1;
+		}
+
+		test_msg("Checking file contents...\n");
+		compare_file_content(fd[count], count);
+
+		test_msg("Closing file descriptor...\n");
+		if (close(fd[count]) == -1) {
+			pr_perror("Close failed");
+			return 1;
+		}
+	}
+
+	pass();
+	return 0;
+}

test/zdtm/static/unlink_multiple_largefiles.desc

+{'flavor': 'ns uns', 'opts': '--ghost-limit 1G'}