[Bug-tar] POSIX_ARCHIVE & big sparse files (>= 2^33 B excluding holes)

[Pavel Raiskup]

Hi, I'm attaching patch for bug in tar for --posix && --sparse options.
Could you please consider applying?

Reproduce:
    1. Create sparse file of "shrunken" size (real data) >= 8^11 bytes.
    2. tar --posix --sparse -cf /dev/null ThatBigFile
    3. Tar fails with:
    tar: value [BIG_NUMBER] out of off_t range 0..8589934591
    tar: Exiting with failure status due to previous errors

Simple test:

    $ cat script
    #!/bin/bash

    COUNT=1 # 1000 * 2 * 10M ~> ~ 20GB

    if ! test -z "$2"; then
        COUNT=$2
    fi

    for i in `seq 0 $(( $COUNT - 1))`; do
        dd if=/dev/urandom of=$1 bs=4K count=$(( 256 * 10 )) \
            seek=$(( $i * 2 * 256 * 10 )) 2> /dev/null
        echo $i
    done

    $ ./script BIGFILE 1000

Sorry that I haven't written test.  I was unable to use genfile utility to
produce such files.  Is the 'dd' utility used as above ^^ ok for portability
reasons?

Pavel

0001-sparse-Fix-bug-in-POSIX_FORMAT.patch
Description: Text Data