[solved]Trouble with lockf on Tru64 client and linux NFS server

[solved]Trouble with lockf on Tru64 client and linux NFS server

[Christian Volkmann]

Solution => no_subtree_check

Hi to everybody,

I had some trouble with locks on a Tru64-NFS client.
"lockf(fd, F_TLOCK, 0)" did not work proper.

no_subtree_check was required for the /etc/exports.

NFS-server: Linux with kernel 2.6.11 ( regular SuSE 9.3 )
NFS-client: Tru64 4.0G

/mountpoint  => Mountpoint
/mountpoint/my => permission 770, owner "my"
/mountpoint/my/subdir => permission 770, owner "my"
/mountpoint/my/subdir/mylock => permission 770, owner "my"

The User "my" was not able to lock the file.

After "chmod 777 /mountpoint/my /mountpoint/my/subdir" the lock worked.

Please see below for a script to reproduce bahavior.

Best regards,

Christian

PS: Linux,AIX and Sun as client worked without no_subtree_check


================cut here for the script============
#!/bin/ksh

# Strange behavior of NFS-lock/permission

MYNAME=${0##*/}

howto()
{
        echo "Syntax: $MYNAME DIRECTORY-TO-CHECK" 1>&2
        exit 99
}

if [ $# -ne 1 ]
then
        howto
fi

TOCHECK=$1
if [ ! -d $TOCHECK ]
then
        echo
        echo "Create directory $TOCHECK"
        mkdir $TOCHECK
        if [ ! -d $TOCHECK ]
        then
                echo "can not create $TOCHECK"
        fi
fi
echo
echo "Create directory $TOCHECK/subdir , chmod 777 for $TOCHECK and $TOCHECK/subdir "
echo
chmod 777 $TOCHECK
mkdir $TOCHECK/subdir
chmod 777 $TOCHECK/subdir
echo "compile c-program"
export CC=gcc
cat > /tmp/$MYNAME.$$.c <<EOP
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <unistd.h>

put_err(const char *point)
{
perror(point);
}
main()
{
int fd,lock;
char b[100] = "$TOCHECK/subdir" ;
        strcat (b, "/");
        strcat(b,"mylock");
        unlink(b);
        fd = open (b, O_CREAT | O_RDWR, 0777);
        if ( fd <= 0 )
        {
                printf("Internal error: errno %d %s\n",errno,strerror(errno));
                exit(0);
        }
        errno=0;
        lock=lockf (fd, F_TLOCK, 0) ;
        if ( lock != 0 )
                printf("Error from lock:%d %d %s\n",lock,errno,strerror(errno));
        else
                printf("Lock OK: %d %d %s\n",lock,errno,strerror(errno));
        exit(lock);
}
EOP
${CC} -o /tmp/$MYNAME.$$.bin /tmp/$MYNAME.$$.c
if [ ! -x /tmp/$MYNAME.$$.bin ]
then
        echo "missing compiled program" 1>&2
        exit 1
fi
/tmp/$MYNAME.$$.bin

echo
echo "Try with no world rwx, chmod 770 for $TOCHECK and $TOCHECK/subdir "
echo
chmod 770 $TOCHECK/subdir
chmod 770 $TOCHECK
/tmp/$MYNAME.$$.bin
if [ $? -ne 0 ]
then
        echo "Fehler aufgetreten !"
fi

rm $TOCHECK/subdir/lockfile
rmdir $TOCHECK/subdir
rmdir $TOCHECK 2>/dev/null
rm /tmp/$MYNAME.$$.bin /tmp/$MYNAME.$$.c


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