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

[Luis Chamberlain <mcgrof@kernel.org>]

On Wed, Nov 03, 2021 at 09:24:34AM -0700, Darrick J. Wong wrote:
> On Mon, Nov 01, 2021 at 08:55:59AM -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 down on.
> 
> <cough> word choice on those last three words...

Will fix thanks.

> > 
> > Cc: Anthony Iliopoulos <ailiopoulos@suse.de>
> > Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> > ---
> >  ltp/fsstress.c | 15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> > 
> > diff --git a/ltp/fsstress.c b/ltp/fsstress.c
> > index 90ae432e..a576afea 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 +944,21 @@ check_cwd(void)
> >  {
> >  #ifdef DEBUG
> >  	struct stat64	statbuf;
> > +	int ret;
> > +
> > +	ret = stat64(".", &statbuf);
> > +	if (ret !=0) {
> 
> Nit: space between '!=' and '0'.

OK.

> > +		fprintf(stderr, "fsstress: check_cwd stat64 failed with: %d (%s)\n",
> > +			ret, strerror(ret));
> 
> ret is set to -1 on error, according to the manpage; to get the real
> error you'd have to call strerror(errno) as the last arg, or be lazy
> and:

I don't want to be lazy here as this is a real issue.

> 		perror("fsstress check_cwd stat64");
> 
> > +		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 (%lu) != top_ino (%lu)\n",
> > +		statbuf.st_ino, top_ino);
> 
> This might want some explicit casting, since this can be defined as
> anything between unsigned long to uint64_t, at least according to the
> glibc headers on my system.

Um, Filipe had suggested something a bit different before. Can you guys
decide and let me know your final preference ? :)

  Luis