This is an updated of my test program, with a new option that allows
us to seek to the middle of the unitialized extent. This allows us to
test more cases. Suggested test cases:
./testcase
./testcase -w 8192
./testcase -s 8192 -w 8192
./testcase -s 8192
./testcase -s 409600
./testcase -d
./testcase -d -w 8192
./testcase -d -s 8192
./testcase -d -s 8192 -w 8192
./testcase -d -s 409600
What I normally do is run it something like this:
mount /scratch ; pushd /scratch; ~/testcase <opts>; popd ; umount /scratch ; debugfs /dev/sdc1 -R "stat test-file"
What to look for is whether the flags field is either 0x480000 or
0x80000. The 0x400000 flag is the EOFBLOCKS_FL flag. If last extent
is uninitialized, then the EOFBLOCKS_FL flag should be set. If the
last extent does not have the "uninit" flag, then the EOFBLOCKS_FL
should be clear.
- Ted
/*
* Testcase for Google Bug 2928259
*
* Run this program while the current directory is in an ext4 filesystem,
* then umount the file system and do a forced fsck (i.e., fsck -f /dev/XXX).
*
* If you get a e2fsck reported corruption, then the kernel is buggy:
*
* Inode 12 should not have EOFBLOCKS_FL set (size 40960, lblk 9)
* Clear<y>? yes
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <getopt.h>
#include <errno.h>
#define FALLOC_FL_KEEP_SIZE 0x01
#ifndef SYS_fallocate
#ifdef __i386__
/* 32-bits */
#define SYS_fallocate 324
#elif __amd64__
/* 64-bits */
#define SYS_fallocate 285
#endif
#endif
int main(int argc, char **argv)
{
int fd, ret, c;
char *buf, *tmp;
unsigned long fsize = 40960;
unsigned long wsize = 40960;
off_t offset = 0;
struct stat st;
int flags = O_CREAT|O_TRUNC|O_RDWR;
while ((c = getopt(argc, argv, "df:s:w:")) != EOF) {
switch (c) {
case 'd':
flags |= O_DIRECT;
break;
case 'f':
fsize = strtoul(optarg, &tmp, 0);
if (*tmp) {
fprintf(stderr, "Bad fsize - %s\n", optarg);
exit(1);
}
break;
case 's':
offset = strtol(optarg, &tmp, 0);
if (*tmp) {
fprintf(stderr, "Bad offset - %s\n", optarg);
exit(1);
}
break;
case 'w':
wsize = strtoul(optarg, &tmp, 0);
if (*tmp) {
fprintf(stderr, "Bad wsize - %s\n", optarg);
exit(1);
}
break;
default:
fprintf(stderr, "Usage: testcase [-d] "
"-f fallocate_size -w write_size\n");
}
}
fd = open("test-file", flags, 0644);
if (fd < 0) {
perror("open");
exit(1);
}
ret = syscall(SYS_fallocate, fd, FALLOC_FL_KEEP_SIZE, 0ULL,
(unsigned long long) fsize);
if (ret) {
perror("fallocate");
exit(1);
}
if ((ret = posix_memalign((void **) &buf, 4096, wsize)) != 0) {
errno = ret;
perror("posix_memalign");
}
if (lseek(fd, offset, SEEK_SET) < 0) {
perror("lseek");
exit(1);
}
memset(buf, 255, wsize);
ret = write(fd, buf, wsize);
if (ret < 0) {
perror("write");
exit(1);
} else if (ret != wsize) {
fprintf(stderr, "Short write: actual %d, expected %lu\n",
ret, wsize);
exit(1);
}
if (fstat(fd, &st) < 0) {
perror("fstat");
exit(1);
}
printf("test-file has inode number %lu\n", (unsigned long) st.st_ino);
printf("size is %lu, blocks*512 is %lu\n", (unsigned long) st.st_size,
(unsigned long) st.st_blocks*512);
close(fd);
exit(0);
}
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