[PATCH v3] fsstress: improve error message on check_cwd() error

[PATCH v3] fsstress: improve error message on check_cwd() error

[Luis Chamberlain]

I ran into an error with generic/083 with xfs due to check_cwd() but
why it failed is not clear because there are two types of
failures:

  o stat64() failed (likely -ENOMEM is my guess)
  o the inode actually changed

Throw a bone out to developers so that in case en error does happen
they know which rabbit hole to go into.

Cc: Anthony Iliopoulos <ailiopoulos@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---

Changes on this v3:

 o Minor nitpick on spaces
 o Changed rabbit hole language
 o enhanced stat64() error message to include errno as well
 o cast things as suggested

 ltp/fsstress.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/ltp/fsstress.c b/ltp/fsstress.c
index 90ae432e..aab64f33 100644
--- a/ltp/fsstress.c
+++ b/ltp/fsstress.c
@@ -9,6 +9,7 @@
 #include <sys/uio.h>
 #include <stddef.h>
 #include <stdbool.h>
+#include <string.h>
 #include "global.h"
 
 #ifdef HAVE_BTRFSUTIL_H
@@ -943,9 +944,22 @@ check_cwd(void)
 {
 #ifdef DEBUG
 	struct stat64	statbuf;
+	int ret;
+
+	ret = stat64(".", &statbuf);
+	if (ret != 0) {
+		fprintf(stderr, "fsstress: check_cwd stat64() returned %d with errno: %d (%s)\n",
+			ret, errno, strerror(errno));
+		goto out;
+	}
 
-	if (stat64(".", &statbuf) == 0 && statbuf.st_ino == top_ino)
+	if (statbuf.st_ino == top_ino)
 		return;
+
+	fprintf(stderr, "fsstress: check_cwd statbuf.st_ino (%llu) != top_ino (%llu)\n",
+		(unsigned long long) statbuf.st_ino,
+		(unsigned long long) top_ino);
+out:
 	assert(chdir(homedir) == 0);
 	fprintf(stderr, "fsstress: check_cwd failure\n");
 	abort();
-- 
2.33.0

Re: [PATCH v3] fsstress: improve error message on check_cwd() error

[Darrick J. Wong]

On Fri, Nov 05, 2021 at 09:44:32AM -0700, Luis Chamberlain wrote:
> I ran into an error with generic/083 with xfs due to check_cwd() but
> why it failed is not clear because there are two types of
> failures:
> 
>   o stat64() failed (likely -ENOMEM is my guess)
>   o the inode actually changed
> 
> Throw a bone out to developers so that in case en error does happen
> they know which rabbit hole to go into.
> 
> Cc: Anthony Iliopoulos <ailiopoulos@suse.de>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

LGTM,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
> 
> Changes on this v3:
> 
>  o Minor nitpick on spaces
>  o Changed rabbit hole language
>  o enhanced stat64() error message to include errno as well
>  o cast things as suggested
> 
>  ltp/fsstress.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> index 90ae432e..aab64f33 100644
> --- a/ltp/fsstress.c
> +++ b/ltp/fsstress.c
> @@ -9,6 +9,7 @@
>  #include <sys/uio.h>
>  #include <stddef.h>
>  #include <stdbool.h>
> +#include <string.h>
>  #include "global.h"
>  
>  #ifdef HAVE_BTRFSUTIL_H
> @@ -943,9 +944,22 @@ check_cwd(void)
>  {
>  #ifdef DEBUG
>  	struct stat64	statbuf;
> +	int ret;
> +
> +	ret = stat64(".", &statbuf);
> +	if (ret != 0) {
> +		fprintf(stderr, "fsstress: check_cwd stat64() returned %d with errno: %d (%s)\n",
> +			ret, errno, strerror(errno));
> +		goto out;
> +	}
>  
> -	if (stat64(".", &statbuf) == 0 && statbuf.st_ino == top_ino)
> +	if (statbuf.st_ino == top_ino)
>  		return;
> +
> +	fprintf(stderr, "fsstress: check_cwd statbuf.st_ino (%llu) != top_ino (%llu)\n",
> +		(unsigned long long) statbuf.st_ino,
> +		(unsigned long long) top_ino);
> +out:
>  	assert(chdir(homedir) == 0);
>  	fprintf(stderr, "fsstress: check_cwd failure\n");
>  	abort();
> -- 
> 2.33.0
>