[Bug-tar] Extracting from a single volume in a multi-volume archive fails

[Göran Uddeborg]

The documentation claims it should be possible to extract files from a
volume of a multi-volume archive without first reading all the
previous volumes:

       You can read each individual volume of a multi-volume archive as if
    it were an archive by itself.  For example, to list the contents of one
    volume, use `--list', without `--multi-volume' specified.  To extract
    an archive member from one volume (assuming it is described that
    volume), use `--extract', again without `--multi-volume'.

While this works for LISTING the volume, it does not seem to work as
expected when trying to actually EXTRACT anything.  Neither for
extracting the entire archive, nor a specific file.

This example illustrates the problem.  In the end, I would have
expected the file "c" to have been extracted, but it isn't there.


freddi$$ tar --version
tar (GNU tar) 1.26
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by John Gilmore and Jay Fenlason.
freddi$$ dd if=/dev/zero bs=4k count=1 of=a
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.0597214 s, 68.6 kB/s
freddi$$ dd if=/dev/zero bs=4k count=1 of=b
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.0554184 s, 73.9 kB/s
freddi$$ dd if=/dev/zero bs=4k count=1 of=c
1+0 records in
1+0 records out
4096 bytes (4.1 kB) copied, 0.0349969 s, 117 kB/s
freddi$$ tar --create --multi-volume --tape-length=8k --blocking-factor=1 
--file=x1.tar a b c
Prepare volume #2 for `x1.tar' and hit return: n x2.tar
freddi$$ tar --list --blocking-factor=1 --file=x2.tar
b
c
freddi$$ rm a b c
freddi$$ tar --extract --blocking-factor=1 --file=x2.tar
tar: b: Cannot extract -- file is continued from another volume
tar: Exiting with failure status due to previous errors
freddi$$ tar --extract --blocking-factor=1 --file=x2.tar c
tar: b: Cannot extract -- file is continued from another volume
tar: c: Not found in archive
tar: Exiting with failure status due to previous errors
freddi$$ ls a b c
ls: cannot access a: No such file or directory
ls: cannot access b: No such file or directory
ls: cannot access c: No such file or directory