Re: [dm-devel] [PATCH v6 0/3] dm: boot a mapped device without an initramfs

From	Alasdair G Kergon <agk@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [dm-devel] [PATCH v6 0/3] dm: boot a mapped device without an initramfs
Date	2017-05-04 15:30 +0200
Message-ID	<tDoZr-3ZE-7@gated-at.bofh.it> (permalink)
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Some more thoughts with your example, dmsetup might look like:

# dmsetup create --bootformat "lroot:uuid,rw,0 2097152 linear 8:2 0, \
2097152 2097152 linear 8:3 0, 4194304 2097152 linear 8:4 0"

- also supporting creating multiple devices if the semi-colon is used

- colon to separate name from uuid, like we already do major:minor 
- colon to separate other flags from rw if we need them in future

- splitting first on a unescaped semi-colons, then on the first two
unescaped commas, and then on unescaped commas and then unescaped spaces
within the table

- backslash escapes the following character so it is never a treated
as a separator
  - lroot\:uuid\;\\\ \"\, would be a device with no uuid and the name
    lroot:uuid;\ ",  (on a non-udev system without name mangling)

# dmsetup ls --bootformat lroot
dm="lroot:uuid,rw,0 2097152 linear 8:2 0, 2097152 2097152 \
linear 8:3 0, 4194304 2097152 linear 8:4 0"

# dmsetup ls --bootformat
(all devices on one output line)

While the code also supports devices in the /dev/sda2 format for 
convenience, please use the preferred 8:2 format in any implementation
and documented examples (to avoid the unnecessary dependency on /dev and
its dependencies).

Or with some alternative name for the option
--boot[format|param]
--short[format]
--kernelparam
--condensed
other suggestions?

dmsetup create --condensed
dmsetup ls --condensed

Alasdair

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Re: [dm-devel] [PATCH v6 0/3] dm: boot a mapped device without an initramfs Enric Balletbo Serra <eballetbo@gmail.com> - 2017-05-04 13:20 +0200
  Re: [dm-devel] [PATCH v6 0/3] dm: boot a mapped device without an         initramfs Alasdair G Kergon <agk@redhat.com> - 2017-05-04 14:20 +0200
    Re: [dm-devel] [PATCH v6 0/3] dm: boot a mapped device without an         initramfs Alasdair G Kergon <agk@redhat.com> - 2017-05-04 15:30 +0200

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