It looks like we’ve run into an NFS client bug in RHEL4.  We stumbled upon this while trying to checkout 
code from a subversion repository to an nfs directory.  Our NFS servers are RHEL3, and we only see this 
bug with RHEL4 clients.  Things work when mounting the directory using ‘noac’, but we can’t live with 
the performance hit.

Here is a test program to demonstrate the bug.

dsr_lnxcu9% pwd
/home/dsr
dsr_lnxcu9% cat svnbug.c
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

#ifndef TESTSIZE
#define TESTSIZE 52
#endif

int main(int argc, char** argv)
{
    char s[TESTSIZE+1];
    struct stat st1, st2;
    int r;
    ssize_t len;

    int fd = open("tmpfile.xyzzy", O_RDWR|O_CREAT|O_EXCL, 0666);

    if (fd < 0) {
       perror("open");
       exit(errno);
    }
    memset(s, 'x', TESTSIZE);
    len = write(fd, s, TESTSIZE);
    if (len < 0) {
       perror("write");
       exit(errno);
    }
    r = fstat(fd, &st1);
    if (0 != r) {
       perror("fstat");
       exit(errno);
    }
    r = fstat(fd, &st2);
    if (0 != r) {
       perror("fstat");
       exit(errno);
    }
    printf("len = %zd, st1 = %zd, st2 = %zd\n",
           len, st1.st_size, st2.st_size);

    close(fd);

    return 0; 
}
dsr_lnxcu9% gcc svnbug.c
dsr_lnxcu9% ~/a.out
len = 52, st1 = 52, st2 = 52
dsr_lnxcu9% cd /cdat/tem/dsr
dsr_lnxcu9% ~/a.out
len = 52, st1 = 0, st2 = 52