Re: [PATCH] Allow user to choose between path or fs-label instead of UUID

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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On 16.09.2012 22:51, Pete Appleton wrote:

> 
> On 16/09/12 18:40, Vladimir 'φ-coder/phcoder' Serbinenko wrote:
>> On 16.09.2012 18:57, Pete Appleton wrote:
>>
>>> Hi all,
>>>
>>> The file attached is intended to allow a Linux user to easily specify
>>> whether GRUB2 should use the traditional device path (/dev/sda1) or the
>>> filesystem label instead of the default UUID scheme.  This functionality
>>> is currently supported by GRUB2 itself but the peripheral files
>>> (grub-mkconfig, 10-linux etc) don't directly support it, requiring the
>>> user to edit the distribution-supplied files on their installation with
>>> the potential for consequent upgrade conflicts.
>>>
>>> This patch adds support for a new environment variable
>>> GRUB_DEVICE_IDENTIFICATION taking as value one of {uuid, label, path};
>>> if not set or invalid then it defaults to uuid so that the current
>>> semantics are respected.  If set to label then the 'search' clause and
>>> root=XXX kernel parameter are written using file system label syntax as
>>> opposed to the current single behaviour of device path if
>>> GRUB_DISABLE_LINUX_UUID=true
>>
>> In this patch the same option has effect on both how device is passed to
>> kernel and how it's identified internally. These 2 parts should be kept
>> separate.
> 
> Update attached which splits the option into GRUB_DEVICE_IDENTIFICATION
> (used by 10-linux for the root FS)

This is Linux-specific then, so it has to contain "LINUX" in its name.

> and GRUB_SEARCH_METHOD, used by
> grub-mkconfig to generate the search clause.
> 
> Pete Appleton
> 
> linux_fslabel_support.patch
> 
> 
> === modified file 'docs/grub.texi'
> --- old/docs/grub.texi	2012-07-31 22:18:57 +0000
> +++ new/docs/grub.texi	2012-09-16 20:45:58 +0000
> @@ -1285,6 +1285,19 @@
>  the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
>  usually more reliable, but in some cases it may not be appropriate.  To
>  disable the use of UUIDs, set this option to @samp{true}.
> +@samp{GRUB_DEVICE_IDENTIFICATION} governs the scheme used instead of
> +the UUID, either the file system label or the traditional device path
> +
> +@item GRUB_DEVICE_IDENTIFICATION
> +Works in conjunction with GRUB_DISABLE_LINUX_UUID to determine how the root filesystem
> +will be identified for the Linux kernel.  The default value is @samp{uuid}, which will use UUIDs. 
> +Other alternatives are @samp{label} to use the file system label, or @samp{path} to use
> +the traditional device path (@samp{/dev/sda1})
> +
> +@item GRUB_SEARCH_METHOD
> +Governs the method used to generate the search directive (as opposed to the Linux root filesysttem)
> +using the same settings as @samp{GRUB_DEVICE_IDENTIFICATION}.  If unset or unrecognised
> +then GRUB will default to searching by UUID
>  
>  @item GRUB_DISABLE_RECOVERY
>  If this option is set to @samp{true}, disable the generation of recovery
> 
> === modified file 'util/grub-mkconfig.in'
> --- old/util/grub-mkconfig.in	2012-04-07 17:49:25 +0000
> +++ new/util/grub-mkconfig.in	2012-09-16 20:42:56 +0000
> @@ -131,10 +131,12 @@
>  # Device containing our userland.  Typically used for root= parameter.
>  GRUB_DEVICE="`${grub_probe} --target=device /`"
>  GRUB_DEVICE_UUID="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_uuid 2> /dev/null`" || true
> +GRUB_DEVICE_LABEL="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2> /dev/null`" || true
>  
>  # Device containing our /boot partition.  Usually the same as GRUB_DEVICE.
>  GRUB_DEVICE_BOOT="`${grub_probe} --target=device /boot`"
>  GRUB_DEVICE_BOOT_UUID="`${grub_probe} --device ${GRUB_DEVICE_BOOT} --target=fs_uuid 2> /dev/null`" || true
> +GRUB_DEVICE_BOOT_LABEL="`${grub_probe} --device ${GRUB_DEVICE_BOOT} --target=fs_label 2> /dev/null`" || 
>

"true" was lost.
Also it doesn't seem that you use this variable anywhere.

  
>  # Filesystem for the device containing our userland.  Used for stuff like
>  # choosing Hurd filesystem module.
> @@ -170,13 +172,24 @@
>  
>  if [ "x${GRUB_ACTUAL_DEFAULT}" = "xsaved" ] ; then GRUB_ACTUAL_DEFAULT="`"${grub_editenv}" - list | sed -n '/^saved_entry=/ s,^saved_entry=,,p'`" ; fi
>  
> +# Default to UUID if GRUB_DEVICE_IDENTIFICATION is undefined or unrecognised
> +if [ "x${GRUB_DEVICE_IDENTIFICATION}" = "x" ] ; then GRUB_DEVICE_IDENTIFICATION="uuid" ; fi
> +if [ "${GRUB_DEVICE_IDENTIFICATION}" != "uuid" -a "${GRUB_DEVICE_IDENTIFICATION}" != "label" -a "${GRUB_DEVICE_IDENTIFICATION}" != "path" ] ; then
> +    GRUB_DEVICE_IDENTIFICATION="uuid"
> +fi
> +if [ "x${GRUB_SEARCH_METHOD}" = "x" ] ; then GRUB_SEARCH_METHOD="uuid" ; fi
> +if [ "${GRUB_SEARCH_METHOD}" != "uuid" -a "${GRUB_SEARCH_METHOD}" != "label" -a "${GRUB_SEARCH_METHOD}" != "path" ] ; then
> +    GRUB_SEARCH_METHOD="uuid"
> +fi
>  

case ... esac would be much more appropriate in this case.

>  # These are defined in this script, export them here so that user can
>  # override them.
>  export GRUB_DEVICE \
>    GRUB_DEVICE_UUID \
> +  GRUB_DEVICE_LABEL \
>    GRUB_DEVICE_BOOT \
>    GRUB_DEVICE_BOOT_UUID \
> +  GRUB_DEVICE_BOOT_LABEL \
>    GRUB_FS \
>    GRUB_FONT \
>    GRUB_PRELOAD_MODULES \
> @@ -216,7 +229,9 @@
>    GRUB_INIT_TUNE \
>    GRUB_SAVEDEFAULT \
>    GRUB_ENABLE_CRYPTODISK \
> -  GRUB_BADRAM
> +  GRUB_BADRAM \
> +  GRUB_DEVICE_IDENTIFICATION \
> +  GRUB_SEARCH_METHOD
>  
>  if test "x${grub_cfg}" != "x"; then
>    rm -f "${grub_cfg}.new"
> 
> === modified file 'util/grub-mkconfig_lib.in'
> --- old/util/grub-mkconfig_lib.in	2012-07-22 18:02:17 +0000
> +++ new/util/grub-mkconfig_lib.in	2012-09-16 20:43:31 +0000
> @@ -146,22 +146,30 @@
>        done
>    fi
>  
> -  # If there's a filesystem UUID that GRUB is capable of identifying, use it;
> +  # If there's a filesystem UUID or label that GRUB is capable of identifying, use it according to GRUB_SEARCH_METHOD
>    # otherwise set root as per value in device.map.
>    fs_hint="`"${grub_probe}" --device "${device}" --target=compatibility_hint`"
>    if [ "x$fs_hint" != x ]; then
>      echo "set root='$fs_hint'"
>    fi
> -  if fs_uuid="`"${grub_probe}" --device "${device}" --target=fs_uuid 2> /dev/null`" ; then
> +  if [ "x${GRUB_SEARCH_METHOD}" = "xlabel" ] && fs_label="`"${grub_probe}" --device "${device}" --target=fs_label 2> /dev/null`" ; then
>      hints="`"${grub_probe}" --device "${device}" --target=hints_string 2> /dev/null`" || hints=
>      echo "if [ x\$feature_platform_search_hint = xy ]; then"
> -    echo "  search --no-floppy --fs-uuid --set=root ${hints} ${fs_uuid}"
> +    echo "  search --no-floppy --label --set=root ${hints} ${fs_label}"
>      echo "else"
> -    echo "  search --no-floppy --fs-uuid --set=root ${fs_uuid}"
> +    echo "  search --no-floppy --label --set=root ${fs_label}"
>      echo "fi"
> +  else
> +    if fs_uuid="`"${grub_probe}" --device "${device}" --target=fs_uuid 2> /dev/null`" ; then
> +      hints="`"${grub_probe}" --device "${device}" --target=hints_string 2> /dev/null`" || hints=
> +      echo "if [ x\$feature_platform_search_hint = xy ]; then"
> +      echo "  search --no-floppy --fs-uuid --set=root ${hints} ${fs_uuid}"
> +      echo "else"
> +      echo "  search --no-floppy --fs-uuid --set=root ${fs_uuid}"
> +      echo "fi"
> +    fi
>    fi
>  }
> -
>  grub_get_device_id ()
>  {
>    device="$1"
> 
> === modified file 'util/grub.d/10_linux.in'
> --- old/util/grub.d/10_linux.in	2012-07-22 18:02:17 +0000
> +++ new/util/grub.d/10_linux.in	2012-09-16 16:21:41 +0000
> @@ -43,13 +43,27 @@
>    ;;
>  esac
>  
> -if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
> -    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
> -    || uses_abstraction "${GRUB_DEVICE}" lvm; then
> -  LINUX_ROOT_DEVICE=${GRUB_DEVICE}
> -else
> -  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
> -fi
> +case x"$GRUB_DEVICE_IDENTIFICATION" in
> +    xpath)
> +        LINUX_ROOT_DEVICE=${GRUB_DEVICE}
> +        ;;
> +    xlabel)
> +        if [ "x${GRUB_DEVICE_LABEL}" = "x" ] \
> +            || ! test -e "/dev/disk/by-label/${GRUB_DEVICE_LABEL}" \
> +            || uses_abstraction "${GRUB_DEVICE}" lvm; then
> +            LINUX_ROOT_DEVICE=${GRUB_DEVICE}
> +        else
> +            LINUX_ROOT_DEVICE=LABEL=\"${GRUB_DEVICE_LABEL}\"
> +        fi;;
> +    *)
> +        if [ "x{GRUB_DEVICE_UUID}" = "x" ] \
> +            || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
> +            || uses_abstraction "${GRUB_DEVICE}" lvm; then
> +            LINUX_ROOT_DEVICE=${GRUB_DEVICE}
> +        else
> +            LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
> +        fi;;      
> +esac
>  
>  GRUBFS="`${grub_probe} --device ${GRUB_DEVICE} --target=fs 2>/dev/null || true`"
>  
> 
> 
> 
> 
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-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko


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