libblkid merged into util-linux-ng

libblkid merged into util-linux-ng

[Karel Zak]

 I've merged the topic/blkid branch into the master branch (upcoming
 util-linux-ng 2.15).

 Note that the library and blkid binary are still "experimental",
 although I don't expect any API changes.

 Feedback and bug reports are welcomed...

    Karel


 New libblkid features:
 ---------------------

 * backwardly compatible ABI and API with old libblkid from e2fsprogs

 * low-level probing interface:

     - blkid_probe_* functions

     - /sbin/blkid -p <device>

 * vol_id compatible output format (e.g. "ID_FS_LABEL_ENC=\x2fboot"):

     - blkid -p -o udev <device>

 * very high-level interface for LABELs/UUIDs evaluation:

    - blkid_evaluate_spec()

    - /sbin/blkid -L <label> | -U <uuid>

   it's strongly recommended to use this interface in your applications
   or scripts. The interface is configurable (by /etc/blkid.conf) and
   works on 2.4, 2.6, udev or non-udev systems.

   It's always better to use /sbin/blkid -L|-U than directly read
   /dev/disk/by-{label,uuid} symlinks.


 * /etc/blkid.conf config file, options are:

   EVALUATE=<method>[,<method>]  # methods are udev and scan;
                                 # default: udev,scan

   SEND_UEVENT=<yes|not>         # send uevent when disk/by-*
                                 # symlink is not valid; default: yes

   CACHE_FILE=<path>             # default: /etc/blkid.tab


 * 24 FS/raid images for blkid regression tests


 TODO
 ----

 e2fsprogs:

    - add --disable-blkid
    - #ifdef BUILD_BLKID for findfs code in tune2fs.c
    - freeze <major>.<minor> libblkid version numbers, the libblkid in
      e2fsprogs should be open for bug fixes or new filesystems only.

 udev:
    - add --disable-volumeid
    - test blkid within udev rules

 - add command line interface for blkid_probe_filter_usage():

	   # blkid -p -o udev --filter-usage filesystems

       # blkid -p -o udev --filter-usage noraid

   and blkid_probe_filter_types():

       # blkid -p -o udev --filter-type nofat

   note that "--filter-usage" is necessary for compatibility with vol_id where
   we in udev rules use things like "vol_id --skip-raid"

 - use blkid_evaluate_spec() in mount, umount, swapon and fsck

 - move fsck to util-linux-ng (we already have some old patches
   from Christoph Hellwig and Matthias Koenig)

 - documentation (probably generated from source code)

-- 
 Karel Zak  <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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Re: libblkid merged into util-linux-ng

[Christoph Hellwig]

On Mon, Feb 16, 2009 at 01:09:38PM +0100, Karel Zak wrote:
>  TODO
>  ----


 * add stripe size / alignment retrival support to libbkid for use
   with mkfs.  This would allow to deprecate libdisk from xfsprogs (1)
   in favour of a common libblkid

(1) http://git.kernel.org/?p=fs/xfs/xfsprogs-dev.git;a=tree;f=libdisk;

Re: libblkid merged into util-linux-ng

[Karel Zak]

On Mon, Feb 16, 2009 at 09:34:52AM -0500, Christoph Hellwig wrote:
> On Mon, Feb 16, 2009 at 01:09:38PM +0100, Karel Zak wrote:
> >  TODO
> >  ----
>  * add stripe size / alignment retrival support to libbkid for use
>    with mkfs.  This would allow to deprecate libdisk from xfsprogs (1)
>    in favour of a common libblkid

 Added to TODO.

> (1) http://git.kernel.org/?p=fs/xfs/xfsprogs-dev.git;a=tree;f=libdisk;

 That would be nice to have something better than exec(/sbin/dmsetup)
 in shared library. It seems that DM developers have no clue about
 /sys/block :-(

    Karel

-- 
 Karel Zak  <kzak-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

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Re: libblkid merged into util-linux-ng

[Martin K. Petersen]

>>>>> "Karel" == Karel Zak <kzak@redhat.com> writes:

Karel> On Mon, Feb 16, 2009 at 09:34:52AM -0500, Christoph Hellwig wrote:
>> On Mon, Feb 16, 2009 at 01:09:38PM +0100, Karel Zak wrote:
>> >  TODO ----
>> * add stripe size / alignment retrival support to libbkid for use
>> with mkfs.  This would allow to deprecate libdisk from xfsprogs (1)
>> in favour of a common libblkid

Karel>  Added to TODO.

My I/O topology patches are finally shaping up and I expect to post them
later this week.  Turned out to be much, much harder than expected to
get it right for the various RAID modes.

My patches will give us alignment and minimum/optimal/maximum I/O sizes
for each block device in sysfs.


>> (1)
>>     http://git.kernel.org/?p=fs/xfs/xfsprogs-dev.git;a=tree;f=libdisk;

Karel>  That would be nice to have something better than
Karel>  exec(/sbin/dmsetup) in shared library. It seems that DM
Karel>  developers have no clue about /sys/block :-(

When the LVM stripe extraction code was originally written I was
explicitly asked to call the lvm commands instead of poking around with
liblvm and internal data structures.  The command output was considered
part of the API.

That in turn spilled over to DM, I guess...

-- 
Martin K. Petersen	Oracle Linux Engineering