Date: Wed, 17 Feb 2010 22:38:30 -0800 From: Tim Kientzle <kientzle@freebsd.org> To: Juergen Lock <nox@jelal.kn-bremen.de> Cc: freebsd-hackers@freebsd.org Subject: Re: "tar tfv /dev/cd0" speedup patch Message-ID: <4B7CE066.4030403@freebsd.org> In-Reply-To: <20100217215940.GA19713@triton8.kn-bremen.de> References: <20100217215940.GA19713@triton8.kn-bremen.de>
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Juergen Lock wrote:
>
> ... since bsdtar/libarchive know iso9660 I just did the command in the
> Subject. It worked, but it was sloow... :( Apparently it read all of
> the disc without seeking. The following patch fixes this, is something
> like this desired? If yes I could look how to do the same for Linux,
Juergen,
This is great! If you can figure out how to get this
right, I would really appreciate it. If you have a
tape drive handy, definitely test with that. My first
attempts here actually broke reading from tape drives,
which is why the current code is so conservative.
Minor style comments:
> else if (S_ISCHR(st.st_mode) &&
> !ioctl(fd, DIOCGMEDIASIZE, &mediasize) && mediasize) {
Please be explicit: S_ISCHR() && ioctl() == 0 && mediasize > 0
> archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
extract_skip_file isn't needed here; we don't read the
contents of device nodes.
Let me know as soon as you have something you're confident of.
Cheers,
Tim
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