Re: Updated test case

[Eric Sandeen <sandeen@redhat.com>]

Ted Ts'o wrote:
> 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

This can be done easily with the xfs_io tool:

# Buffered writes
xfs_io    -f -F -c "falloc -k 0 40960" -c "pwrite     0 40960" eof1
xfs_io    -f -F -c "falloc -k 0 40960" -c "pwrite  8192  8192" eof2
xfs_io    -f -F -c "falloc -k 0 40960" -c "pwrite  8192 40960" eof3
xfs_io    -f -F -c "falloc -k 0 40960" -c "pwrite 40960 40960" eof4
# O_DIRECT writes
xfs_io -d -f -F -c "falloc -k 0 40960" -c "pwrite     0 40960" eof5
xfs_io -d -f -F -c "falloc -k 0 40960" -c "pwrite  8192  8192" eof6
xfs_io -d -f -F -c "falloc -k 0 40960" -c "pwrite  8192 40960" eof7
xfs_io -d -f -F -c "falloc -k 0 40960" -c "pwrite 40960 40960" eof8

and if we want this to stay fixed, it needs to be part of a test suite.

I'll send an xfstest but it'd be really great if could could work
inside the xfstests framework when devising testcases...

Ted, is just checking for fs corruption is enough or do you think a
test needs the debugfs stat inspection step?  It'd be easy enough
to special-case a debugfs step for ext4.

> 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.  

only if that last extent is past i_size, though...

> If the
> last extent does not have the "uninit" flag, then the EOFBLOCKS_FL
> should be clear.

And the above should always be true.

Thanks,
-Eric



>        	  					- 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);
> }
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html