VirtualBox Shared Folder has Insufficient inodes

Question

I'm trying to use Vagrant + VirtualBox to build a Yocto based project. The build process is aborting before it starts compiling because it does a sanity check for disk space and inode. It appears that vboxfs mounts only show as having 1k free inodes (which is Yocto's PANIC threshold)

vagrant@vagrant-ubuntu-trusty-64:/vagrant$ df -ih
Filesystem     Inodes IUsed IFree IUse% Mounted on
/dev/sda1        2.5M   88K  2.5M    4% /
none             975K     2  975K    1% /sys/fs/cgroup
udev             974K   401  973K    1% /dev
tmpfs            975K   322  975K    1% /run
none             975K     1  975K    1% /run/lock
none             975K     1  975K    1% /run/shm
none             975K     2  975K    1% /run/user
vagrant          1000     0  1000    0% /vagrant

I can rsync the shared directory into the VM or checkout the code, but that sort of negates the benefits of Vagrant. Is it possible to tweak the vboxfs mount settings to make it have more inodes?

Edit

Modifying the config file to change the panic thresholds seems to have worked. There are actually two levels of checking. A "STOP" level and an "ABORT" level. By default "STOP" is set to 100,000 inodes. Changing both STOP and ABORT to 999 inodes allows the build to proceed, but I'm not sure if it will cause other problems down the road.

Answer 1

Unfortunately, there’s no easy solution. The value is hardcoded at src/VBox/Additions/linux/sharedfolders/utils.c:

int sf_get_volume_info(struct super_block *sb, STRUCT_STATFS *stat)
{
    struct sf_glob_info *sf_g;
    SHFLVOLINFO SHFLVolumeInfo;
    uint32_t cbBuffer;
    int rc;

    sf_g = GET_GLOB_INFO(sb);
    cbBuffer = sizeof(SHFLVolumeInfo);
    rc = VbglR0SfFsInfo(&client_handle, &sf_g->map, 0, SHFL_INFO_GET | SHFL_INFO_VOLUME,
                        &cbBuffer, (PSHFLDIRINFO)&SHFLVolumeInfo);
    if (RT_FAILURE(rc))
        return -RTErrConvertToErrno(rc);

    stat->f_type        = NFS_SUPER_MAGIC; /* XXX vboxsf type? */
    stat->f_bsize       = SHFLVolumeInfo.ulBytesPerAllocationUnit;
    stat->f_blocks      = SHFLVolumeInfo.ullTotalAllocationBytes
                        / SHFLVolumeInfo.ulBytesPerAllocationUnit;
    stat->f_bfree       = SHFLVolumeInfo.ullAvailableAllocationBytes
                        / SHFLVolumeInfo.ulBytesPerAllocationUnit;
    stat->f_bavail      = SHFLVolumeInfo.ullAvailableAllocationBytes
                        / SHFLVolumeInfo.ulBytesPerAllocationUnit;
    stat->f_files       = 1000;
    stat->f_ffree       = 1000; /* don't return 0 here since the guest may think
                                 * that it is not possible to create any more files */
    stat->f_fsid.val[0] = 0;
    stat->f_fsid.val[1] = 0;
    stat->f_namelen     = 255;
    return 0;
}

Of course, if you’re willing to compile the Shared Folders kernel module yourself (should be very easy), you can easily change these values to something higher.

To build the kernel modules, download the appropriate VirtualBox source tree and run the following commands in its root:

./configure --only-additions

After getting it to succeed (indicating that all dependencies are installed), you should be able to follow the on-screen instructions. Unfortunately, I’ve run into a GCC bug, I’ll investigate more tomorrow.