[linux-lvm] libdevmapper's handling of devices with spaces in the name
zkabelac at redhat.com
Wed Feb 26 18:21:40 UTC 2014
Dne 26.2.2014 18:04, Phillip Susi napsal(a):
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> So if I tell dmsetup to create a device named 'foo bar' it ends up
> actually naming it 'foo\x20bar'. If I run parted on 'foo\x20bar', it
> appears that libdevmapper helpfully tries to unescape the name,
> returning 'foo bar' from dm_task_get_name(). Unfortunately, such a
> dev node does not actually exist so this creates a problem trying to
> open it.
> This seems like a bug in libdevmapper. I'd say the name of the actual
> dev node should not be escaped in the first place.
This is no longer true for 'modern' systems with udev.
libdevmapper no longer creates any /dev nodes - it's all job for udev.
And udev has had in dark ages the idea to use 'space' as a separator
for device names in device list. Thus it 'invented' escaping/mangling names.
(There are more prohibited characters which used to be used for normal device
names (see man dmsetup mangling))
If you have system without udev - you could disable name mangling on i.e.
There is also envvar DM_DEFAULT_NAME_MANGLING_MODE_ENV_VAR_NAME
which could be used to set prefered behavior.
So there is no bug in libdm side - but I'll not comment on the rest...
I'll just note - it really means all tools now would need to be fixed to
handle udev mangled names properly...
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