volumes are available, instead of getting stuck in a loop calling
getvol(). Normally restore in 'x' or 'i' modes will ask for a new
(earlier) volume when the current inode number on the tape is greater
than the last inode to be restored, since there can be no further
inodes of interest on that volume. However we don't want to change
volumes in this case either if the user explicitly said that there
are no more tapes, or if we are looking at the first volume.
When no more volumes are available but there are still inodes that
we have not found, we now just fall through to the code that prints
out a list of any missing files, so the restore completes normally.
Also simplify the logic a bit by always returning to the start of
the main for(;;) loop whenever the volume has changed.
This should completely fix the "Changing volumes on pipe input" bug
that is often observed when restoring dumps of active filesystems.
PR: bin/4176, bin/34604, misc/34675
cfd8a00918