Date: Tue, 25 Nov 2008 13:15:16 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: Luigi Rizzo <rizzo@iet.unipi.it>, current@freebsd.org Subject: Re: small newfs_msdos addition Message-ID: <492BDE44.7060402@icyb.net.ua> In-Reply-To: <20081125094125.GA18669@onelab2.iet.unipi.it> References: <20081125094125.GA18669@onelab2.iet.unipi.it>
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on 25/11/2008 11:41 Luigi Rizzo said the following:
> If there are no objections I'd like to commit the small patch below
> to newfs_msdos.c -- all it does is create a fake geometry if
> it cannot get the media size, which is handy when you want to
> create a filesystem image on a regular file.
>
> Before the patch you need to do
>
> newfs_msdos -h 32 -s 64 -o 0 -S 512 -s `du -k /the/file` /the/file
>
> after the patch it becomes
>
> newfs_msdos /the/file
>
> which is a bit more friendly especially if you have to type it manually.
>
> cheers
> luigi
>
>
>> svn diff head/sbin
> Index: head/sbin/newfs_msdos/newfs_msdos.c
> ===================================================================
> --- head/sbin/newfs_msdos/newfs_msdos.c (revision 185290)
> +++ head/sbin/newfs_msdos/newfs_msdos.c (working copy)
> @@ -725,9 +725,20 @@
>
> /* Maybe it's a floppy drive */
> if (lp == NULL) {
> - if (ioctl(fd, DIOCGMEDIASIZE, &ms) == -1)
> - errx(1, "Cannot get disk size, %s", strerror(errno));
> - if (ioctl(fd, FD_GTYPE, &type) != -1) {
> + if (ioctl(fd, DIOCGMEDIASIZE, &ms) == -1) {
> + struct stat st;
> +
> + bzero(&st, sizeof(st));
> + if (fstat(fd, &st))
> + err(1, "Cannot get disk size");
> + /* create a fake geometry for a file image */
> + ms = st.st_size;
> + dlp.d_secsize = 512;
> + dlp.d_nsectors = 64;
> + dlp.d_ntracks = 32;
> + dlp.d_secperunit = ms / dlp.d_secsize;
> + lp = &dlp;
> + } else if (ioctl(fd, FD_GTYPE, &type) != -1) {
> dlp.d_secsize = 128 << type.secsize;
> dlp.d_nsectors = type.sectrac;
> dlp.d_ntracks = type.heads;
Please also consider this PR:
http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/121182
and this message from phk in a related thread:
http://lists.freebsd.org/pipermail/freebsd-fs/2008-February/004483.html
--
Andriy Gapon
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