Dear all,
Recently we had some IRC discussion about adding support for a new string
format to create multiple devices in one line so we can use this new format
as a kernel cmdline parameter to create device-mapped devices without a
initramfs.
This first patchset is a first proposal for this new format, I'm either
interested on, know you opinion about the new format and know if the way
I introduced this new option is right or not. Is the first time I play with
this code so take this as first draft.
Bootformat is specified as a simple string of data separated by commas and
optionally semi-colons, where:
- a comma is used to separate fields like name, uuid, mode and table (specifies
one device)
- a semi-colon is used to separate devices.
So the format will look like this:
<dev_name>,<uuid>,<mode>,<table>[,<table>+][;<dev_name>,<uuid>,<mode>,<table>[,<table>+]]+
See the following example.
To supply the new format to dmsetup (splitted in multiple lines for readibility)
$ dmsetup -v create --bootformat "lroot,none,rw, \
0 2097152 linear 7:0 0,\
2097152 2097152 linear 7:1 0,\
4194304 2097152 linear 7:2 0;\
mroot,,rw,\
0 2097152 linear 7:3 0;\
kroot,,rw,\
0 2097152 linear 7:4 0"
Name: lroot
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 253, 3
Number of targets: 3
UUID: none
Name: mroot
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 253, 4
Number of targets: 1
Name: kroot
State: ACTIVE
Read Ahead: 256
Tables present: LIVE
Open count: 0
Event number: 0
Major, minor: 253, 5
Number of targets: 1
To ask dmsetup to display your existing devices in this format:
$ dmsetup table --bootformat lroot mroot kroot
lroot,none,rw,4194304 2097152 linear 7:2 0;mroot,,rw,0 2097152 linear 7:3 0;kroot,,rw,0 2097152 linear 7:4 0;
Finally I know that the code needs more work but I'm wonder if you expect
something like this or if I'm following the wrong way.
Next thing to do:
- support embedded '\,' and '\;' among the other escaped options altready
supported in string data
Waiting for your feedback,
Enric Balletbo i Serra (2):
dmsetup: add support to output devices in bootformat style
dmsetup: add support to create devices when bootformat is used
tools/dmsetup.c | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 153 insertions(+), 2 deletions(-)
--
2.9.3
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
