On Fri, Jan 15, 2010 at 19:56, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 15 Jan 2010, Karel Zak wrote: >> >> For example Reiser superblok could be at offset 65536. > > So what? > > Look fo the common cases first. > > It's insane to probe for zfs, ufs or reiserfs after you have already found > a vfat filesystem. As Karel already mentioned, we can not afford that. There are far too many volumes with competing signatures out there. And the kernel vfat driver accepts any volume with just a few matching bytes, mounts the volume and corrupts any other filesystem. We must check for all possibly valid signatures and refuse to handle non-unique signature devices automatically. Such devices need to be handled by custom configs. It's scary in the first place, that we mount any volume that shows up by guessing its filesystem, and we must be very careful here not to destroy data by doing this. Experience has shown, that fat signatures are completely unreliable regarding fs guessing, and therefore we need to do it like it is done. Karel, most of the filesystems that require reading in areas not in the first few sectors also have a pretty high minimal size requirement. Udev's old vol_id had some guards in there for the raid stuff, not to try to probe for the signatures if the filesystem would not fit on the volume in the first place. I'm very sure, zfs can not live on a 0.5 MB volume. :) Care to check libblkid, and possibly add such checks before letting the probe functions reading stuff off the volume? >> I'll fix -S and remove the large 69kB read and then you can create a >> special udev rule for the device. > > I don' think you understand - "special udev rules" are totally bogus. Yeah, there is no point in adding such options. We do not want to add any custom stuff, it needs to made working out-of-the-box. Thanks, Kay -- To unsubscribe from this list: send the line "unsubscribe util-linux-ng" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
