Bug 870128
| Summary: | improve blkid documentation | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Joe Vlcek <jvlcek> |
| Component: | util-linux-ng | Assignee: | Karel Zak <kzak> |
| Status: | CLOSED ERRATA | QA Contact: | qe-baseos-daemons |
| Severity: | medium | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 6.4 | CC: | apevec, azelinka, psklenar |
| Target Milestone: | rc | Keywords: | ManPageChange |
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2013-11-21 20:44:05 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Some more observations:
#1)
Bare-metal seems to work OK:
It seems the reason I wasn't seeing any output on bare-metal is because
the label for the cdrom is not "CDROM" as it is on the VM. On bare-metal
the label for the cdrom is: "RHEL_6.3 x86_64 Disc 1"
What I observer on Bare-metal seem OK although the label seems a bit verbose.
What I observer on the vSphere VM seems incorrect.
On bare-metal:
--------------
# blkid /dev/cdrom
/dev/cdrom: LABEL="RHEL_6.3 x86_64 Disc 1" TYPE="iso9660"
# blkid -odevice -t LABEL="RHEL_6.3 x86_64 Disc 1"
/dev/cdrom
# blkid -odevice -t LABEL="RHEL_6.3 x86_64 Disc 1" -l
/dev/sr0
On vSphere VM:
--------------
# blkid -tLABEL=CDROM -odevice
# blkid -tLABEL=CDROM -odevice -l
/dev/sr0
#2) Oddly, on VM, the output seems to be correct after issuing
blkid /dev/cdrom
On vSphere VM:
--------------
# blkid -tLABEL=CDROM -odevice
# blkid -tLABEL=CDROM -odevice -l
/dev/sr0
# blkid /dev/cdrom
/dev/cdrom: LABEL="CDROM" TYPE="iso9660"
# blkid -tLABEL=CDROM -odevice
/dev/cdrom
# blkid -tLABEL=CDROM -odevice -l
/dev/sr0
This request was not resolved in time for the current release. Red Hat invites you to ask your support representative to propose this request, if still desired, for consideration in the next release of Red Hat Enterprise Linux. Please consider addressing this for the next release. The libblkid does not probe removable devices by default, these devices are not in /proc/partitions. This is expected behaviour to avoid performance issues. If you manually specify the device name on command line (e.h. blkid /dev/cdrom) then the device is added to the /etc/blkid/blkid.tab) cache file and blkid will probe this device as well. The command "blkid -l -t LABEL=" (or UUID=) works differently, it uses /dev/disk/by-label udev symlinks to translate the tag to device name, so it bypasses the cache as well as /proc/partitions. Maybe it's confusing (and badly documented), but all this is expected behaviour. We have backported new command lsblk(8) to RHEL6, you can try to use lsblk --fs if you want to have overview of the devices and labels. Note that, the latest 3.x kernels probably list removable in the /proc/partitions. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2013-1648.html |
Description of problem: On a vSphere VM, without the "-l" flag blkid returns no cdrom device when it should according to the man page. On the below bare-metal even when using the "-l" flag blkid doesn't list the cdrom device. # dmidecode <snip> Handle 0x0001, DMI type 1, 27 bytes System Information Manufacturer: Hewlett-Packard Product Name: HP Z210 Workstation Version: Not Specified Serial Number: 2UA1230QGZ UUID: 3C8F4300-8ACF-11E0-8BB7-2C27D719FBBF Wake-up Type: Power Switch SKU Number: XM856AV Family: 103C_53335X G=D </snip> Version-Release number of selected component (if applicable): I have seen this on RHEL6.3 and RHEL6.4 How reproducible: Steps to Reproduce: 1. boot system with a cdrom 2. attempt to use blkid without "-l" flag to list the cdrom. # blkid -tLABEL=CDROM -odevice Actual results: No output is produced Expected results: blkid should list the cdrom on bare-metal and vSphere without having to specify the "-l" flag. Without the "-l" flag blkid should, as described in the man page blkid(8), print all of the devices that match the search parameter. Additional info: The device is correctly returned if the "-l" flag is used. e.g.: # blkid -tLABEL=CDROM -odevice -l /dev/sr0 However the blkid(8) man page states in the last sentence of the description of the "-l" flag that: "If this option is not specified, blkid will print all of the devices that match the search parameter." The "-l" flag is not needed on other platforms (e.g.: Fedora and Ubuntu) and should behave as documented in the man page.