From: "Darrick J. Wong" <darrick.wong@oracle.com>
Subject: Re: /dev/disk/by-label missing after upgrade to 1.42.7
Date: Thu, 13 Jun 2013 15:56:32 -0700
Message-ID: <20130613225632.GB6021@blackbox.djwong.org>
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 <51BA3B3B.9090508@redhat.com>
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Cc: Autif Khan <autif.mlist@gmail.com>, linux-ext4@vger.kernel.org
To: Eric Sandeen <sandeen@redhat.com>
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On Thu, Jun 13, 2013 at 04:35:55PM -0500, Eric Sandeen wrote:
> On 6/13/13 2:45 PM, Autif Khan wrote:
> > On Thu, Jun 13, 2013 at 2:55 PM, Autif Khan <autif.mlist@gmail.com> wrote:
> >> Hi,
> >>
> >> We are using /dev/disk/by-label/OURLABEL to mount USB disk partitions.
> >>
> >> We were using Ubuntu 12.04 with 1.42 version of e2fsprogs - where we
> >> encountered SSD corruption issues on unclean powerdown. It was
> >> suggested that we upgrade to the latest e2fsprogs
> >> (http://marc.info/?l=linux-ext4&m=137035378614543&w=2).
> >>
> >> After the upgrade to 1.42.7, we do not have /dev/disk/by-label
> >>
> >> I am not sure if this is the right place to ask this - but I thought
> >> that I should start here and ask in udev mailing list later - (that
> >> whole thing about correlation mumble causation).
> >>
> >> I am still researching how /dev/disk/by-label comes into existence -
> >> please advice if there is something obvious that I am missing.
> >>
> > 
> > Thanks djwong#ext4 for all the help on IRC
> > 
> > It seems like blkid -o udev /dev/sdb1 displays info about the volume -
> > which is used by udev rules to populates /dev/disk/by-label
> > 
> > The output when e2fsprogs version 1.42 was used:
> > 
> > ubuntu@mac0013950af6fb:/lib/udev/rules.d$ sudo blkid -o udev -p /dev/sdb1
> 
> ubuntu isn't using blkid from util-linux?
> 
> That's really where it's maintained these days, a little surprised that
> blkid's still in use from e2fsprogs, though I don't know my ubuntu
> releases.  Maybe this is Crufty Crow?  ;)
> 
> Fedora has been building w/ --disable-libblkid for quite a while,
> just FWIW.

<shrug> /me runs Ubutnu 12.04 w/ e2fsprogs 1.42.7 (by stealing the 1.42.5
package and mashing 1.42.7 into it, muahahha) and it works fine for me:

$ which blkid
/sbin/blkid
$ sudo /sbin/blkid -o udev -p /dev/sdb2
ID_FS_LABEL=blackbox-boot
ID_FS_LABEL_ENC=blackbox-boot
ID_FS_UUID=c5487a72-cb84-4ed9-b44c-50850fba11dd
ID_FS_UUID_ENC=c5487a72-cb84-4ed9-b44c-50850fba11dd
ID_FS_VERSION=1.0
ID_FS_TYPE=ext4
ID_FS_USAGE=filesystem
ID_PART_ENTRY_SCHEME=gpt
ID_PART_ENTRY_UUID=55b7a0e7-5135-4e34-b8a0-2371e580e926
ID_PART_ENTRY_TYPE=0fc63daf-8483-4772-8e79-3d69d8477de4
ID_PART_ENTRY_NUMBER=2
ID_PART_ENTRY_OFFSET=133120
ID_PART_ENTRY_SIZE=524288
ID_PART_ENTRY_DISK=8:16

--D
> 
> -Eric
> 
> > ID_FS_LABEL=KOKO
> > ID_FS_LABEL_ENC=KOKO
> > ID_FS_UUID=56D8-F5EE
> > ID_FS_UUID_ENC=56D8-F5EE
> > ID_FS_VERSION=FAT32
> > ID_FS_TYPE=vfat
> > ID_FS_USAGE=filesystem
> > ID_PART_ENTRY_SCHEME=dos
> > ID_PART_ENTRY_TYPE=0xb
> > ID_PART_ENTRY_FLAGS=0x80
> > ID_PART_ENTRY_NUMBER=1
> > ID_PART_ENTRY_OFFSET=32
> > ID_PART_ENTRY_SIZE=251616
> > ID_PART_ENTRY_DISK=8:16
> > 
> > 
> > The output when e2fsprogs version 1.42.7 was used:
> > ubuntu@mac001395089897:~$ sudo blkid -o udev /dev/sda1
> > Invalid output format udev. Choose from value,
> >     device, list, or full
> > 
> > BTW, sudo blkid -o full /dev/sdb1 worked just fine - had the LABEL and
> > everything.
> > 
> > Also - looks like 1.42.7 does not support the -p option. From the man page:
> > 
> > -p     Switch to low-level superblock probing mode (bypass cache).
> > 
> > Is there a configuration option that will allow blkid to display udev
> > output formats? I could not find with ./configure --help
> > 
> > Thanks
> > 
> > Autif
> > --
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> > 
> 
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