Viewing: sendfile_grouplock.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2015 Cray Inc, all rights reserved.
*
* Copyright (c) 2017, Intel Corporation.
*
* Author: Frank Zago.
*
* A few portions are extracted from llapi_layout_test.c
*/
/*
* The CRC32 implementation is from RFC 1952, which bears the
* following notice:
*
* Copyright (c) 1996 L. Peter Deutsch
*
* Permission is granted to copy and distribute this document for any
* purpose and without charge, including translations into other
* languages and incorporation into compilations, provided that the
* copyright notice and this notice are preserved, and that any
* substantive changes or deletions from the original are clearly
* marked.
*/
/*
* The purpose of this test is to exert the group lock ioctls in
* conjunction with sendfile. Some bugs were found when both were used
* at the same time. See LU-6368 and LU-6371.
*
* The program will exit as soon as a non zero error code is returned.
*
* It can be called like this:
*
* dd if=/dev/zero of=/mnt/lustre/foo1 bs=1M count=40
* ./sendfile_grouplock /mnt/lustre/foo1
*/
#include <stdlib.h>
#include <errno.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#include <poll.h>
#include <sys/sendfile.h>
#include <lustre/lustreapi.h>
#define ERROR(fmt, ...) \
fprintf(stderr, "%s: %s:%d: %s: " fmt "\n", \
program_invocation_short_name, __FILE__, __LINE__, \
__func__, ## __VA_ARGS__);
#define DIE(fmt, ...) \
do { \
ERROR(fmt, ## __VA_ARGS__); \
exit(EXIT_FAILURE); \
} while (0)
#define ASSERTF(cond, fmt, ...) \
do { \
if (!(cond)) \
DIE("assertion '%s' failed: "fmt, \
#cond, ## __VA_ARGS__); \
} while (0)
#define PERFORM(testfn) \
do { \
fprintf(stderr, "Starting test " #testfn " at %lld\n", \
(unsigned long long)time(NULL)); \
testfn(); \
fprintf(stderr, "Finishing test " #testfn " at %lld\n", \
(unsigned long long)time(NULL)); \
} while (0)
/* This test will copy from source_file to dest_file */
static const char *source_file;
static char *dest_file;
static unsigned long source_crc; /* CRC32 of original file */
/*
* A small CRC32 implementation, from RFC 1952
*/
/* Table of CRCs of all 8-bit messages. */
static unsigned long crc_table[256];
/* Flag: has the table been computed? Initially false. */
static int crc_table_computed;
/* Make the table for a fast CRC. */
static void make_crc_table(void)
{
unsigned long c;
int n, k;
for (n = 0; n < 256; n++) {
c = (unsigned long) n;
for (k = 0; k < 8; k++) {
if (c & 1)
c = 0xedb88320L ^ (c >> 1);
else
c = c >> 1;
}
crc_table[n] = c;
}
crc_table_computed = 1;
}
/*
* Update a running crc with the bytes buf[0..len-1] and return the
* updated crc. The crc should be initialized to zero. Pre- and
* post-conditioning (one's complement) is performed within this
* function so it shouldn't be done by the caller. Usage example:
*
* unsigned long crc = 0L;
*
* while (read_buffer(buffer, length) != EOF) {
* crc = update_crc(crc, buffer, length);
* }
* if (crc != original_crc) error();
*/
static unsigned long update_crc(unsigned long crc,
unsigned char *buf, int len)
{
unsigned long c = crc ^ 0xffffffffL;
int n;
if (!crc_table_computed)
make_crc_table();
for (n = 0; n < len; n++)
c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
return c ^ 0xffffffffL;
}
/* Cleanup our test file. */
static void cleanup(void)
{
unlink(dest_file);
}
/* Compute the CRC32 of a file */
static unsigned long compute_crc(const char *fname)
{
unsigned char buf[1024*1024];
unsigned long crc = 0L;
struct stat stbuf;
int fd;
int rc;
size_t filesize;
fd = open(fname, O_RDONLY);
ASSERTF(fd >= 0, "open failed for '%s': %s",
fname, strerror(errno));
rc = fstat(fd, &stbuf);
ASSERTF(rc == 0, "fstat of '%s' failed: %s", fname, strerror(errno));
filesize = stbuf.st_size;
while (filesize != 0) {
size_t to_read = sizeof(buf);
ssize_t sret;
if (to_read > filesize)
to_read = filesize;
sret = read(fd, buf, to_read);
ASSERTF(sret >= 0, "read of %zu bytes from '%s' failed: %s",
to_read, fname, strerror(errno));
ASSERTF(sret > 0, "unexpected EOF for '%s'",
fname);
filesize -= sret;
crc = update_crc(crc, buf, sret);
}
close(fd);
return crc;
}
/* Helper. Copy a file with sendfile. The destination will be
* created. If a group lock is 0, it means do not take one.
*/
static int sendfile_copy(const char *source, int source_gid,
const char *dest, int dest_gid)
{
int rc;
struct stat stbuf;
size_t filesize;
int fd_in;
int fd_out;
fd_in = open(source, O_RDONLY);
ASSERTF(fd_in >= 0, "open failed for '%s': %s",
source, strerror(errno));
rc = fstat(fd_in, &stbuf);
ASSERTF(rc == 0, "fstat of '%s' failed: %s", source, strerror(errno));
filesize = stbuf.st_size;
if (source_gid != 0) {
rc = llapi_group_lock(fd_in, source_gid);
ASSERTF(rc == 0, "cannot set group lock %d for '%s': %s",
source_gid, source, strerror(-rc));
}
fd_out = open(dest, O_WRONLY | O_TRUNC | O_CREAT, 0644);
ASSERTF(fd_out >= 0, "creation failed for '%s': %s",
dest, strerror(errno));
if (dest_gid != 0) {
rc = llapi_group_lock(fd_out, dest_gid);
ASSERTF(rc == 0, "cannot set group lock %d for '%s': %s",
dest_gid, dest, strerror(-rc));
}
/* Transfer by 10M blocks */
while (filesize != 0) {
size_t to_copy = 10*1024*1024;
ssize_t sret;
if (to_copy > filesize)
to_copy = filesize;
sret = sendfile(fd_out, fd_in, NULL, to_copy);
rc = errno;
/* Although senfile can return less than requested,
* that should not happen under present conditions. At
* the very least, make sure that a decent size was
* copied. See LU-6371.
*/
ASSERTF(sret != 0, "sendfile read 0 bytes");
ASSERTF(sret > 0, "sendfile failed: %s", strerror(rc));
ASSERTF(sret > 100*1024,
"sendfile read too little data: %zd bytes", sret);
if (sret != to_copy)
fprintf(stderr,
"Warning: sendfile returned %zd bytes instead of %zu requested\n",
sret, to_copy);
filesize -= sret;
}
if (dest_gid != 0) {
rc = llapi_group_unlock(fd_out, dest_gid);
ASSERTF(rc == 0, "cannot clear group lock %d for '%s': %s",
dest_gid, dest, strerror(-rc));
}
if (source_gid != 0) {
rc = llapi_group_unlock(fd_in, source_gid);
ASSERTF(rc == 0, "cannot clear group lock %d for '%s': %s",
source_gid, source, strerror(-rc));
}
close(fd_out);
close(fd_in);
return 0;
}
/* Basic sendfile, without lock taken */
static void test10(void)
{
unsigned long crc;
cleanup();
sendfile_copy(source_file, 0, dest_file, 0);
sync();
crc = compute_crc(dest_file);
ASSERTF(source_crc == crc, "CRC differs: %lu and %lu", source_crc, crc);
}
/* sendfile, source locked */
static void test11(void)
{
unsigned long crc;
cleanup();
sendfile_copy(source_file, 85543, dest_file, 0);
sync();
crc = compute_crc(dest_file);
ASSERTF(source_crc == crc, "CRC differs: %lu and %lu", source_crc, crc);
}
/* sendfile, destination locked */
static void test12(void)
{
unsigned long crc;
cleanup();
sendfile_copy(source_file, 0, dest_file, 98765);
sync();
crc = compute_crc(dest_file);
ASSERTF(source_crc == crc, "CRC differs: %lu and %lu", source_crc, crc);
}
/* sendfile, source and destination locked, with same lock number */
static void test13(void)
{
const int gid = 8765;
unsigned long crc;
cleanup();
sendfile_copy(source_file, gid, dest_file, gid);
sync();
crc = compute_crc(dest_file);
ASSERTF(source_crc == crc, "CRC differs: %lu and %lu", source_crc, crc);
}
/* sendfile, source and destination locked, with different lock number */
static void test14(void)
{
unsigned long crc;
cleanup();
sendfile_copy(source_file, 98765, dest_file, 34543);
sync();
crc = compute_crc(dest_file);
ASSERTF(source_crc == crc, "CRC differs: %lu and %lu", source_crc, crc);
}
/* Basic sendfile, without lock taken, to /dev/null */
static void test15(void)
{
sendfile_copy(source_file, 0, "/dev/null", 0);
sync();
}
/* sendfile, source locked, to /dev/null */
static void test16(void)
{
sendfile_copy(source_file, 85543, "/dev/null", 0);
sync();
}
int main(int argc, char *argv[])
{
int rc;
if (argc != 2 || argv[1][0] != '/') {
fprintf(stderr,
"Argument must be an absolute path to a Lustre file\n");
return EXIT_FAILURE;
}
source_file = argv[1];
rc = asprintf(&dest_file, "%s-dest", source_file);
if (rc == -1) {
fprintf(stderr, "Allocation failure\n");
return EXIT_FAILURE;
}
/* Play nice with Lustre test scripts. Non-line buffered output
* stream under I/O redirection may appear incorrectly.
*/
setvbuf(stdout, NULL, _IOLBF, 0);
cleanup();
atexit(cleanup);
/* Compute crc of original file */
source_crc = compute_crc(source_file);
PERFORM(test10);
PERFORM(test11);
PERFORM(test12);
PERFORM(test13);
PERFORM(test14);
PERFORM(test15);
PERFORM(test16);
return EXIT_SUCCESS;
}
