This is my very rough tester for testing seek_hole/seek_data. Please look over
it and make sure we all agree that the semantics are correct. My btrfs patch
passes with this and ext3 passes as well. I still have to added fallocate() to
it, but for now this seems to cover most of the corner cases. Thanks,
Josef
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#define SEEK_HOLE 3
#define SEEK_DATA 4
#define ERROR(str) \
fprintf(stderr, "%s: pos=%lu, errno=%d\n", str, pos, errno)
static int reset_file(int fd)
{
int ret;
ret = ftruncate(fd, 0);
if (ret < 0) {
fprintf(stderr, "Truncate failed: %d\n", errno);
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
char buf[4096 * 4];
ssize_t bytes;
off_t pos;
int prealloc_is_hole = 0;
int whole_file_is_data = 0;
int ret;
int i;
int fd;
fd = open("testfile", O_RDWR|O_CREAT|O_TRUNC, 0644);
if (fd < 0) {
fprintf(stderr, "Failed to open testfile: %d\n", errno);
return 1;
}
/* Empty file */
printf("Testing an empty file\n");
pos = lseek(fd, 0, SEEK_DATA);
if (pos != -1) {
if (errno == EINVAL) {
fprintf(stderr, "Kernel does not support seek "
"hole/data\n");
close(fd);
return 1;
}
if (errno != ENXIO)
ERROR("Seek data did not return a proper error");
close(fd);
return 1;
}
pos = lseek(fd, 0, SEEK_HOLE);
if (pos != -1 && errno != ENXIO) {
ERROR("Seek hole did not return a proper error");
close(fd);
return 1;
}
memset(&buf, 'a', 4096 * 4);
/*
* All data file
*/
printf("Testing a normal data filled file\n");
for (i = 0; i < 4; i++) {
bytes = write(fd, &buf, 4096);
if (bytes < 4096) {
fprintf(stderr, "Failed to write to testfile: %d\n",
errno);
close(fd);
return 1;
}
}
pos = lseek(fd, 0, SEEK_HOLE);
if (pos != (4096 * 4) || pos == -1) {
ERROR("Seek hole failed to dump us out at the end of the file");
close(fd);
return 1;
}
pos = lseek(fd, 0, SEEK_DATA);
if (pos != 0) {
ERROR("Seek data failed to dump us out at the beginning of the"
" file");
close(fd);
return 1;
}
/*
* File with a hole at the front and data at the end
*/
printf("Testing file with hole at the start and data in the rest\n");
if (reset_file(fd)) {
close(fd);
return 1;
}
bytes = pwrite(fd, &buf, 4096 * 3, 4096);
if (bytes < (4096 * 3)) {
fprintf(stderr, "Failed to write to testfile: %d\n");
close(fd);
return 1;
}
pos = lseek(fd, 0, SEEK_HOLE);
if (pos != 0 && pos != (4096 * 4)) {
ERROR("Seek hole failed to return 0");
close(fd);
return 1;
} else if (pos == (4096 * 4)) {
whole_file_is_data = 1;
printf("Current file system views treats the entire file as "
"data\n");
}
pos = lseek(fd, 0, SEEK_DATA);
if (pos != 4096 || (pos != 0 && whole_file_is_data)) {
if (whole_file_is_data)
ERROR("Seek data failed to return 0");
else
ERROR("Seek data failed to return 4096");
close(fd);
return 1;
}
if (whole_file_is_data) {
pos = lseek(fd, 1, SEEK_DATA);
if (pos != -1 && errno != ENXIO) {
ERROR("Seek data failed to retun an error");
close(fd);
return 1;
}
}
/*
* File with a hole at the end and data at the beginning
*/
printf("Testing file with hole at the end and data at the beginning\n");
if (reset_file(fd)) {
close(fd);
return 1;
}
ret = ftruncate(fd, 4096 * 4);
if (ret < 0) {
fprintf(stderr, "Truncate failed: %d\n", errno);
close(fd);
return 1;
}
pwrite(fd, &buf, 4096 * 3, 0);
if (bytes < (4096 * 3)) {
fprintf(stderr, "Failed to write to testfile: %d\n", errno);
close(fd);
return 1;
}
pos = lseek(fd, 0, SEEK_HOLE);
if (pos != (4096 * 3) || (pos != (4096 * 4) && whole_file_is_data)) {
ERROR("Seeking hole didn't work right");
close(fd);
return 1;
}
if (whole_file_is_data) {
pos = lseek(fd, 4096, SEEK_DATA);
if (pos != 4096) {
ERROR("Seeking data didn't return the same offset");
close(fd);
return 1;
}
printf("No more tests to run since we treat the whole file as "
"data\n");
goto out;
}
pos = lseek(fd, pos, SEEK_HOLE);
if (pos != (4096 * 3)) {
ERROR("Seek hole didn't return same position");
close(fd);
return 1;
}
pos = lseek(fd, pos+1, SEEK_HOLE);
if (pos != (4096 * 4)) {
ERROR("Seek hole didn't return the end of the file");
close(fd);
return 1;
}
pos = lseek(fd, pos, SEEK_DATA);
if (pos != -1 && errno != ENXIO) {
ERROR("Seek data didn't return ENXIO");
close(fd);
return 1;
}
/*
* Hole - Data - Hole - Data file
*/
printf("Testing file [Hole][Data][Hole][Data]\n");
if (reset_file(fd)) {
close(fd);
return 1;
}
ret = ftruncate(fd, 4096 * 4);
if (ret < 0) {
fprintf(stderr, "ftruncate failed: %d\n", errno);
close(fd);
return 1;
}
bytes = pwrite(fd, &buf, 4096, 4096);
if (bytes < 4096) {
fprintf(stderr, "Failed to write: %d\n", errno);
close(fd);
return 1;
}
bytes = pwrite(fd, &buf, 4096, 4096 * 3);
if (bytes < 4096) {
fprintf(stderr, "Failed to write: %d\n", errno);
close(fd);
return 1;
}
pos = lseek(fd, 0, SEEK_DATA);
if (pos != 4096) {
ERROR("Seek data did not return 4096");
close(fd);
return 1;
}
pos = lseek(fd, pos, SEEK_HOLE);
if (pos != (4096 * 2)) {
ERROR("Seek hole did not return 4096*2");
close(fd);
return 1;
}
pos = lseek(fd, pos, SEEK_DATA);
if (pos != (4096 * 3)) {
ERROR("Seek data did not return 4096*3");
close(fd);
return 1;
}
out:
close(fd);
return 0;
}
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