Odd Results Using -d and -D Together with mkfs.jffs2

[Grant Erickson <gerickson@nuovations.com>]

I've run into what I can only imagine is user error regarding mkfs.jffs2
when creating a root file system image for a target system.

At present, I run mkfs.jffs2 with super-user credentials and point it at a
temporary root file system tree (created with a tool that does
gather/scatter of build tree results) and end up with the precisely desired
image with all the right permissions, files, etc.:

    % sudo mkfs.jffs2 -v --big-endian --no-cleanmarkers --pad 512 \
    --pagesize 512 --eraseblock 16384 -d /tmp/tmp.gtKxQ31829 -o root.img

at about 11 MiB in size.

However, clearly, I'd like to be able to run a build without requiring
super-user credentials. So, I added an option to my gather/scatter tool to
generate a device table so that it can skip setting permissions and creating
device nodes and let mkfs.jffs2 do that:

    % mkfs.jffs2 -v --big-endian --no-cleanmarkers --pad 512 \
    --pagesize 512 --eraseblock 16384 -d /tmp/tmp.EdxjV32751 \
    -D devices.txt -o root.img

However, I end up with two problems, the first of which seems counter to
what I had expected based on my interpretation of the manual reference page:

    1) I end up with an image that is 2x larger (22 MiB) than was
       created in the super-user credentialed case without the device table.

       Based on the output with '-v' enabled, mkfs.jffs2 seems to create
       every regular file and directory twice, once with the permissions
       (the current build user) from the source file from '-d' and again
       with the permissions specified (privileged users) in '-D'. For
       example:

        ...
        /usr
            d 0775         0              1000:1000 bin
            d 0775         0              1000:1000 lib
            d 0775         0              1000:1000 libexec
            d 0775         0              1000:1000 sbin
            d 0775         0              1000:1000 share
            d 0775         0                 0:4   bin
            d 0775         0                 0:4   lib
            d 0775         0                 0:4   libexec
            d 0775         0                 0:4   sbin
            d 0775         0                 0:4   share
        ...

    2) It does not seem to be able to set the permissions of any directories
       at the top of the file tree:

        mkfs.jffs2: skipping device_table entry '/bin': no parent directory!
        mkfs.jffs2: skipping device_table entry '/dev': no parent directory!
        mkfs.jffs2: skipping device_table entry '/etc': no parent directory!
        mkfs.jffs2: skipping device_table entry '/lib': no parent directory!
        mkfs.jffs2: skipping device_table entry '/sys': no parent directory!
        mkfs.jffs2: skipping device_table entry '/tmp': no parent directory!
        mkfs.jffs2: skipping device_table entry '/usr': no parent directory!
        mkfs.jffs2: skipping device_table entry '/var': no parent directory!
        ...

Given the two example bits of output above, my device table looks like:

/bin    d   0775    0   4   0   0   -   -   -
/dev    d   0775    0   4   0   0   -   -   -
/etc    d   0775    0   4   0   0   -   -   -
/lib    d   0775    0   4   0   0   -   -   -
/sys    d   0775    0   4   0   0   -   -   -
/tmp    d   0775    0   4   0   0   -   -   -
/usr    d   0775    0   4   0   0   -   -   -
/usr/bin    d   0775    0   4   0   0   -   -   -
/usr/lib    d   0775    0   4   0   0   -   -   -
/usr/libexec    d   0775    0   4   0   0   -   -   -
/usr/sbin   d   0775    0   4   0   0   -   -   -
/usr/share  d   0775    0   4   0   0   -   -   -
/var    d   0775    0   4   0   0   -   -   -

Any insight on what user error I am tripping over here?

Regards,

Grant Erickson