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    SubjectRe: What to do about the 2TB limit on HDIO_GETGEO ?
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    Greg KH <gregkh@suse.de> wrote:
    > On Tue, Mar 25, 2008 at 04:05:32PM -0700, H. Peter Anvin wrote:

    >>> How does this have anything to do with boot times? Do you really have a
    >>> foolish shell script that iteratorates over every single disk in the
    >>> sysfs tree for every disk? What does it do that for?
    >>
    >> Any time you want to get the sysfs information for a filesystem which is
    >> already mounted, that's what you're forced to do.
    >>
    >>> I thought we were talking about 2TB disks here, with a proposed new
    >>> ioctl, not foolishness of boot scripts...
    >>
    >> I pointed out that having a way to map device numbers to sysfs directories
    >> would have the same effect, *and* would be usable for other purposes. I'd
    >> rather see that than a new ioctl, and another, and another...
    >
    > Again, a simple udev rule will give you that today if you really want
    > it...

    So e.g. lilo should depend on sysfs and *a*special*configuration* of udev,
    while the admin MUST NOT use mknod'ed device files nor manually create
    symlinks pointing to them, and not use relative path names?
    That's plain stupid.

    > And I think 'udevinfo' can be used to retrieve this information as well.

    $ udevinfo /dev/hda
    missing option
    $ udevinfo /dev/hda --help
    Usage: udevinfo OPTIONS
    --query=<type> query database for the specified value:
    name name of device node
    symlink pointing to node
    path sysfs device path
    env the device related imported environment
    all all values

    --path=<devpath> sysfs device path used for query or chain
    --name=<name> node or symlink name used for query

    --root prepend to query result or print udev_root
    --attribute-walk print all SYSFS_attributes along the device chain
    --export-db export the content of the udev database
    --help print this text
    $ udevinfo --name=/dev/hda
    missing option
    $ udevinfo --name=/dev/hda --query=all
    P: /block/hda
    N: hda
    S: disk/by-id/ata-Maxtor_2F040L0_F1748ZQE
    S: disk/by-path/pci-0000:00:0f.0-ide-0:0
    E: DEVTYPE=disk
    E: ID_TYPE=disk
    E: ID_MODEL=Maxtor_2F040L0
    E: ID_SERIAL=F1748ZQE
    E: ID_REVISION=VAM51JJ0
    E: ID_BUS=ata
    E: ID_PATH=pci-0000:00:0f.0-ide-0:0


    As you can see, it gives no major:minor information. But it is in the DB:

    $ cd /dev/.udev/db
    $ grep -l hda * 2>/dev/null
    \x2fblock\x2fhda
    \x2fblock\x2fhda\x2fhda1
    $ cat "\x2fblock\x2fhda"
    N:hda
    S:disk/by-id/ata-Maxtor_2F040L0_F1748ZQE
    S:disk/by-path/pci-0000:00:0f.0-ide-0:0
    M:3:0
    E:DEVTYPE=disk
    E:ID_TYPE=disk
    E:ID_MODEL=Maxtor_2F040L0
    E:ID_SERIAL=F1748ZQE
    E:ID_REVISION=VAM51JJ0
    E:ID_BUS=ata
    E:ID_PATH=pci-0000:00:0f.0-ide-0:0

    What a great tool - for making linux look bad.




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