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bug#53212: feature request: mount option to specify the device number
From: |
Bernhard Voelker |
Subject: |
bug#53212: feature request: mount option to specify the device number |
Date: |
Wed, 12 Jan 2022 18:46:33 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 |
tag 53212 notabug
close 53212
stop
On 1/12/22 17:59, Joachim Wagner wrote:
> Not sure whether this is coreutils or kernel. Maybe both.
>
> A filesystem's device number such as reported by `stat` can be derived from
> major and minor of the underlying block device, e.g. xfs, or be allocated at
> mount time, e.g. btrfs. Even in the former case, the device number can change
> between restarts, e.g. when multiple dm-crypt devices are created in
> different
> order. Changing device numbers cause trouble for applications that use the
> device number to identify a filesystem across restarts, e.g. KDE's baloo file
> indexer.
>
> A mount option to specify the device number would fix this trouble without
> requiring applications to move to alternative ways of identifying
> filesystems,
> e.g. based on UUIDs. This option could be general, i.e. the device number can
> be set for any filesystem, including those that normally derive it from major
> and minor of their block device(s).
>
> The implementation would probably be simplified if the specified device
> numbers must come from a reserved pool. Otherwise, care must be taken that
> the
> numbers do not collide with automatically assigned device numbers, including
> those allocated later.
>
> Replaces bug #53209
>
> References:
> https://bugs.kde.org/show_bug.cgi?id=402154
> https://bugs.kde.org/show_bug.cgi?id=404057
> https://bugs.kde.org/show_bug.cgi?id=413694
> https://unix.stackexchange.com/questions/345220/btrfs-how-to-get-real-device-id
> https://stackoverflow.com/questions/4309882/device-number-in-stat-command-output/4309947
mount is a command from the util-linux package, hence you'd be better off asking
on their mailing list <util-linux@vger.kernel.org>.
FWIW: mount already knows quite a list of alternatives how to specify the source
device:
mount --help | sed -n '/^Source:/,/^$/p'
Source:
-L, --label <label> synonym for LABEL=<label>
-U, --uuid <uuid> synonym for UUID=<uuid>
LABEL=<label> specifies device by filesystem label
UUID=<uuid> specifies device by filesystem UUID
PARTLABEL=<label> specifies device by partition label
PARTUUID=<uuid> specifies device by partition UUID
ID=<id> specifies device by udev hardware ID
<device> specifies device by path
<directory> mountpoint for bind mounts (see --bind/rbind)
<file> regular file for loopdev setup
As this is not related to coreutils, I'm hereby closing this issue in our
bug tracker.
Have a nice day,
Berny