NFS files still accessible from original pathname after being renamed

Issue

• Directory entries are still accessible via access() and stat() even after they have been renamed.
• Test program:

int
main(int argc, char **argv)
{
    int rc = 0;
    char *fname1;
    char *fname2;

    if (argc != 3) {
        printf("Usage: %s <file1> <file2>\n", argv[0]);
        exit(1);
    }

    fname1 = argv[1];
    fname2 = argv[2];

    rc = mkdir(fname1, 0666);
    if (rc < 0) {
        perror("mkdir(fname1)");
        exit(1);
    }

    rc = mkdir(fname2, 0666);
    if (rc < 0) {
        perror("mkdir(fname2)");
        exit(1);
    }

    rc = rename(fname1, fname2);
    if (rc < 0) {
        perror("rename");
        exit(1);
    }

    rc = access(fname1, F_OK);
    if (rc < 0) {
        printf("success\n");
        exit(1);
    }

    printf("file %s exists!\n", fname1);

    return 0;
}

The test passes when the source and target directories have less than 32 characters and reproduces the bug if either source or target has 32 or more characters.

# gcc -Wall -o nfs_test nfs_test.c
# mount localhost:/mnt/test /mnt/nfs
# cd /mnt/nfs
# ~/nfs_test a 0123456789012345678901234567890
success
# ~/nfs_test a 01234567890123456789012345678901
file a exists!
# stat a
  File: `a'
  Size: 4096        Blocks: 8          IO Block: 131072 directory
Device: 20h/32d Inode: 315028      Links: 1
Access: (0644/drw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2014-03-25 14:52:01.858764868 +1100
Modify: 2014-03-25 14:52:01.858764868 +1100
Change: 2014-03-25 14:52:01.858764868 +1100
# cat a
cat: a: No such file or directory

• File 'a' should not exist.