[SOLVED] Is there a good way to detect a stale NFS mount

Is there a good way to detect a stale NFS mount

I have a procedure I want to initiate only if several tests complete successfully.

One test I need is that all of my NFS mounts are alive and well.

Can I do better than the brute force approach:

mount | sed -n "s/^.* on \(.*\) type nfs .*$/\1/p" | 
while read mount_point ; do 
  timeout 10 ls $mount_point >& /dev/null || echo "stale $mount_point" ; 
done

Here timeout is a utility that will run the command in the background, and will kill it after a given time, if no SIGCHLD was caught prior to the time limit, returning success/fail in the obvious way.

In English: Parse the output of mount, check (bounded by a timeout) every NFS mount point. Optionally (not in the code above) breaking on the first stale mount.

Solution

You could write a C program and check for ESTALE.

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <iso646.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

int main(){
    struct stat st;
    int ret;
    ret = stat("/mnt/some_stale", &st);
    if(ret == -1 and errno == ESTALE){
        printf("/mnt/some_stale is stale\n");
        return EXIT_SUCCESS;
    } else {
        return EXIT_FAILURE;
    }
}