[Bug-tar] Fix & testcase: Option -C does not work in combination with -u

[Pavel Raiskup]

Hello,

tar (it seems that at least version from 1.23 to 1.26) fails to sync the
archive contents against archived directory with the '--update' option
when changing directory (the -C option) is active.

Original report by Nicolas Mitsis:

    https://bugzilla.redhat.com/688567

Steps to reproduce (or see the attached test-case):

    # prepare directory
    mkdir /tmp/dir
    touch /tmp/dir/a

    # create archive
    tar -C /tmp -cf /tmp/archive.tar dir

    # add something to filesystem
    mkdir /tmp/dir/b
    touch /tmp/dir/b/c

    # try to update archive to synchronize with '/tmp/dir'
    tar -C /tmp -uf /tmp/archive.tar dir

    --> tar output this: <--
    tar: dir/b: Cannot stat: No such file or directory
    tar: dir/a: Cannot stat: No such file or directory
    tar: Exiting with failure status due to previous errors

It looks like the only problem was that target children of given
directory 'dir' (these files are expanded on update.c:160) were not
inheriting the 'name->change_dir' info from its parent.  Could you please
consider proposed fix in attachement?  Separate test-case is also
attached.

Pavel

0001-tar-new-test-for-update-option-update03.at.patch
Description: Binary data

binix9noLN2M1.bin
Description: Binary data