Re: [PATCH v6 1/2] fsstress: add mwrite/mread into test operation list

[Eryu Guan <eguan@redhat.com>]

On Thu, Mar 23, 2017 at 12:37:17AM +0800, Zorro Lang wrote:
> mmap as a popular and basic operation, most of softwares use it to
> access files. More and more customers report bugs related with
> mmap/munmap and other stress conditions.
> 
> So add mmap read/write test into fsstress to increase mmap related
> stress to reproduce or find more bugs easily.
> 
> Signed-off-by: Zorro Lang <zlang@redhat.com>
> ---
> 
> Hi,
> 
> V6 do below changes:
> 
> 1) pick all common things from mwrite and mread into new do_mmap() function.
> 
> Before V6, mwrite try to extend the file size by truncate and mwrite on new
> extended place. But the reviewer suggest removing the truncate operation,
> so mwrite and mread will be nearly same, except one does memset(), and the
> other does memcpy().
> 
> 2) Add sys/mman.h into configure.ac, and include it in global.h
> 
> Thanks,
> Zorro
> 
>  configure.ac   |   1 +
>  ltp/fsstress.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/global.h   |   4 +++
>  3 files changed, 115 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index fa48d2f..246f92e 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -32,6 +32,7 @@ AC_HEADER_STDC
>  			xfs/platform_defs.h	\
>  			btrfs/ioctl.h		\
>  			cifs/ioctl.h		\
> +			sys/mman.h		\
>      ])
>  
>  AC_CHECK_HEADERS([xfs/xfs_log_format.h],,,[
> diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> index 7e7cf60..2f65034 100644
> --- a/ltp/fsstress.c
> +++ b/ltp/fsstress.c
> @@ -69,6 +69,8 @@ typedef enum {
>  	OP_LINK,
>  	OP_MKDIR,
>  	OP_MKNOD,
> +	OP_MREAD,
> +	OP_MWRITE,
>  	OP_PUNCH,
>  	OP_ZERO,
>  	OP_COLLAPSE,
> @@ -168,6 +170,8 @@ void	getdents_f(int, long);
>  void	link_f(int, long);
>  void	mkdir_f(int, long);
>  void	mknod_f(int, long);
> +void	mread_f(int, long);
> +void	mwrite_f(int, long);
>  void	punch_f(int, long);
>  void	zero_f(int, long);
>  void	collapse_f(int, long);
> @@ -208,6 +212,8 @@ opdesc_t	ops[] = {
>  	{ OP_LINK, "link", link_f, 1, 1 },
>  	{ OP_MKDIR, "mkdir", mkdir_f, 2, 1 },
>  	{ OP_MKNOD, "mknod", mknod_f, 2, 1 },
> +	{ OP_MREAD, "mread", mread_f, 2, 0 },
> +	{ OP_MWRITE, "mwrite", mwrite_f, 2, 1 },
>  	{ OP_PUNCH, "punch", punch_f, 1, 1 },
>  	{ OP_ZERO, "zero", zero_f, 1, 1 },
>  	{ OP_COLLAPSE, "collapse", collapse_f, 1, 1 },
> @@ -2656,6 +2662,110 @@ mknod_f(int opno, long r)
>  }
>  
>  void
> +do_mmap(int opno, long r, int prot)
> +{
> +#ifdef HAVE_SYS_MMAN_H
> +	char		*addr;
> +	int		e;
> +	pathname_t	f;
> +	int		fd;
> +	size_t		len;
> +	__int64_t	lr;
> +	off64_t		off;
> +	int		flags;
> +	struct stat64	stb;
> +	int		v;
> +	char		st[1024];
> +
> +	init_pathname(&f);
> +	if (!get_fname(FT_REGFILE, r, &f, NULL, NULL, &v)) {
> +		if (v)
> +			printf("%d/%d: do_mmap - no filename\n", procid, opno);
> +		free_pathname(&f);
> +		return;
> +	}
> +	fd = open_path(&f, O_RDWR);
> +	e = fd < 0 ? errno : 0;
> +	check_cwd();
> +	if (fd < 0) {
> +		if (v)
> +			printf("%d/%d: do_mmap - open %s failed %d\n",
> +			       procid, opno, f.path, e);
> +		free_pathname(&f);
> +		return;
> +	}
> +	if (fstat64(fd, &stb) < 0) {
> +		if (v)
> +			printf("%d/%d: do_mmap - fstat64 %s failed %d\n",
> +			       procid, opno, f.path, errno);
> +		free_pathname(&f);
> +		close(fd);
> +		return;
> +	}
> +	if (stb.st_size == 0) {
> +		if (v)
> +			printf("%d/%d: do_mmap - %s%s zero size\n", procid, opno,
> +			       f.path, st);
                                      ^^^^
st is used with uninitialized content.

> +		free_pathname(&f);
> +		close(fd);
> +		return;
> +	}
> +
> +	inode_info(st, sizeof(st), &stb, v);
> +	lr = ((__int64_t)random() << 32) + random();
> +	off = (off64_t)(lr % stb.st_size);
> +	off &= (off64_t)(~(sysconf(_SC_PAGE_SIZE) - 1));
> +	len = (size_t)(random() % MIN(stb.st_size - off, FILELEN_MAX)) + 1;
> +
> +	flags = (random() % 2) ? MAP_SHARED : MAP_PRIVATE;
> +	addr = mmap(NULL, len, prot, flags, fd, off);
> +	e = (addr == MAP_FAILED) ? errno : 0;
> +	if (e && v)
> +		printf("%d/%d: do_mmap - mmap failed %s%s [%lld,%d,%s] %d\n",
> +		       procid, opno, f.path, st, (long long)off, (int)len,
> +		       (flags & MAP_PRIVATE) ? "MAP_PRIVATE" : "MAP_SHARED", e);

I think we can return here if mmap failed.

> +
> +	if (addr != MAP_FAILED) {

then no need to do this check here.

> +		if (prot & PROT_WRITE) {
> +		/* PROT_READ maybe set, if PROT_WRITE is set. Not vice versa */
> +			memset(addr, nameseq & 0xff, len);
> +		} else {
> +			char *buf;
> +			if ((buf = malloc(len)) != NULL) {
> +				memcpy(buf, addr, len);
> +				free(buf);
> +			}
> +		}
> +		e = munmap(addr, len) < 0 ? errno : 0;
> +		if (e && v)
> +			printf("%d/%d: do_mmap - munmap failed %s%s [%lld,%d] %d\n",
> +			       procid, opno, f.path, st, (long long)off,
> +			       (int)len, e);
> +	}
> +	if (v)
> +		printf("%d/%d: %s %s%s [%lld,%d,%s] %d\n",
> +		       procid, opno, (prot & PROT_WRITE) ? "mwrite" : "mread",
> +		       f.path, st, (long long)off, (int)len,
> +		       (flags & MAP_PRIVATE) ? "MAP_PRIVATE" : "MAP_SHARED", e);
> +
> +	free_pathname(&f);
> +	close(fd);
> +#endif
> +}
> +
> +void
> +mread_f(int opno, long r)
> +{
> +	do_mmap(opno, r, PROT_READ);
> +}
> +
> +void
> +mwrite_f(int opno, long r)
> +{
> +	do_mmap(opno, r, PROT_WRITE);

These do_mmap calls should be protected by #ifdef HAVE_SYS_MMAN_H too,
otherwise PROT_READ|WRITE are not defined.

But I'm not sure if this HAVE_SYS_MMAN_H detection is really needed, I'm
fine with either way.

Thanks,
Eryu

> +}
> +
> +void
>  punch_f(int opno, long r)
>  {
>  #ifdef HAVE_LINUX_FALLOC_H
> diff --git a/src/global.h b/src/global.h
> index f63246b..3920c0d 100644
> --- a/src/global.h
> +++ b/src/global.h
> @@ -178,4 +178,8 @@
>  
>  #endif /* HAVE_LINUX_FALLOC_H */
>  
> +#ifdef HAVE_SYS_MMAN_H
> +#include <sys/mman.h>
> +#endif
> +
>  #endif /* GLOBAL_H */
> -- 
> 2.7.4
> 
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