On Tue, 16 Aug 2011, Xianglong Du wrote:
> Hi Alan,
>
> >> + num_sectors = size >> curlun->l_blkbits; /* File size in logic-block-size blocks */
> >> min_sectors = 1;
> >> if (curlun->cdrom) {
> >> num_sectors &= ~3; /* Reduce to a multiple of 2048 */
>
> > And as long as you're using variable logical block sizes, you might as
> > well set l_blkbits here to 11, because cdroms always use a block size
> > of 2048.
>
> I've test cdrom as mass storage according to your suggestion:
> if (curlun->cdrom)
> curlun->l_blkbits = 11;
> but it seems that the cdrom doesn't work:
> FAT: logical sector size too small for device (logical sector size = 512)
> after set l_blkbits to 9 for cdrom, it works properly.
As Michal pointed out, cdroms don't contain FAT filesystems. You
should test with an ISO9660 filesystem.
> The code in earlier version is also set to default value 9:
> num_sectors = size >> 9; /* File size in 512-byte blocks */
Because I didn't want to go to the trouble of supporting variable block
sizes.
> min_sectors = 1;
> if (curlun->cdrom) {
> num_sectors &= ~3; /* Reduce to a multiple of 2048 */
> min_sectors = 300*4; /* Smallest track is 300 frames */
> So I think we should set l_blkbits to 9 for cdrom.
>
> Do you have any suggestions?
Same as before: Change it to 11.
Alan Stern
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