Peter Cordes <[EMAIL PROTECTED]> wrote:
> Note that the ftruncate man page says ftruncate can fail (when called to
> extend a file) on filesystems like VFAT. I don't know if vfat even supports
> sparse files, but you need to make sure the file actually ends up at the
> right length, unless you want to just return an error when someone uses cp
> --sparse to a lame filesystem.
VFAT does not support sparse files, and so cp --sparse=always
simply creates a file full of zero bytes when copying a sparse
file to such a file system. No problem.
You can demonstrate it like this on a Linux system.
BTW, cp's use of ftruncate works fine (returns 0) there,
but even if it were to fail, there is code to handle that.
cd /tmp &&
dd bs=1 seek=128K of=sp < /dev/null 2> /dev/null &&
dd if=/dev/zero of=1 bs=8192 count=50 2> /dev/null &&
mkdir mnt && mkfs -t vfat 1 > /dev/null &&
mount -oloop 1 mnt && cd mnt &&
cp --sparse=always /tmp/sp . &&
du -sk sp
The above prints this:
128 sp
Run this to clean up:
cd /tmp && umount /tmp/mnt && rm -r 1 mnt sp
--
To UNSUBSCRIBE, email to [EMAIL PROTECTED]
with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
