On Fri, Jun 24, 2016 at 12:19 PM, Karel Zak <kzak@xxxxxxxxxx> wrote: > On Tue, Jun 21, 2016 at 04:59:39PM +0300, Yigal Korman wrote: >> I have a question regarding this patch in util-linux: >> "blkid: don't ignore info about partitions on non-formated devices" >> (commit f8098e2b2c0a8a98ccb603f53dfba0cc05683a39) >> >> I wanted to know what was the trigger for this change? what's the reasoning >> behind it? > > I guess inconsistency with man page: > > Note that low-level probing also returns information about partition > table type (PTTYPE tag) and partitions (PART_ENTRY_* tags). Huh, interesting, I didn't notice that. > > .. and I'm not able to found if someone complained on mailing list. > >> Background: >> I have an Linux automation script that formats a given partition and mounts >> it. >> In order to verify that the partition is empty (ie no other data exists >> there) I've been using 'blkid -p <partition>; [[ $? != 2 ]] && fail". >> Which stopped working correctly when I moved to Ubuntu 16.04. >> I've tracked the issue to the patch mentioned above. >> >> To me this patch seems to counter blkid behavior - returning the partition >> information when the given device is the partition doesn't describe what >> the device contains. > > Yes, the patch seems pretty controversial. I'll think about revert. > >> The same way that if /dev/sda is part of LVM, then 'blkid -p /dev/sda' will >> return the LVM information, but doing 'blkid -p /dev/mapper/vg-lv' will >> return what's inside the logical volume and not the logical volume >> information (and nothing if the empty). >> >> Do you have a suggestion for a different method for testing if a device is >> empty? > > lsblk -n -o FSTYPE /dev/sda1 This doesn't return a different exit code when nothing is found, but checking the output would work. I went with a similar solution of checking the output of blkid: blkid -p /dev/sda1 | grep -qw TYPE && echo "device is not empty" Thanks! > > -- > Karel Zak <kzak@xxxxxxxxxx> > http://karelzak.blogspot.com -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
