[LTP] [PATCH] tst_find_backing_dev: match mount point if major/minor can't be found

[Cyril Hrubis]

Hi!
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>  lib/tst_device.c | 31 +++++++++++++++++++++----------
>  1 file changed, 21 insertions(+), 10 deletions(-)
> 
> diff --git a/lib/tst_device.c b/lib/tst_device.c
> index d296f9118cde..e560ec97460b 100644
> --- a/lib/tst_device.c
> +++ b/lib/tst_device.c
> @@ -506,14 +506,22 @@ unsigned long tst_dev_bytes_written(const char *dev)
>  	return dev_bytes_written;
>  }
>  
> +static int count_match_len(const char *first, const char *second)
> +{
> +	int len = 0;
> +
> +	while (*first && *first++ == *second++)
> +		len++;
> +
> +	return len;
> +}
> +
>  void tst_find_backing_dev(const char *path, char *dev)
>  {
>  	struct stat buf;
>  	FILE *file;
> -	char line[PATH_MAX];
> -	char *pre = NULL;
> -	char *next = NULL;
> -	unsigned int dev_major, dev_minor, line_mjr, line_mnr;
> +	char line[PATH_MAX], mnt_point[PATH_MAX], mnt_source[PATH_MAX];
> +	unsigned int dev_major, dev_minor, line_mjr, line_mnr, best_match_len = 0;
>  
>  	if (stat(path, &buf) < 0)
>  		tst_brkm(TWARN | TERRNO, NULL, "stat() failed");
> @@ -524,17 +532,20 @@ void tst_find_backing_dev(const char *path, char *dev)
>  	*dev = '\0';
>  
>  	while (fgets(line, sizeof(line), file)) {
> -		if (sscanf(line, "%*d %*d %d:%d", &line_mjr, &line_mnr) != 2)
> +		if (sscanf(line, "%*d %*d %d:%d %*s %s %*s %*s %*s %*s %s",
> +			&line_mjr, &line_mnr, mnt_point, mnt_source) != 4)
>  			continue;

We did this before and it didn't work see: 5dfd9c29f094e3024ceab760715456436188ecab

We really have to parse the string based on the dash (" - ") to make it
work reliably.

Other than that the rest of the patch looks reasonable.

-- 
Cyril Hrubis
chrubis@suse.cz