mirror of
https://github.com/torvalds/linux.git
synced 2024-11-11 06:31:49 +00:00
ce5d36aac2
This simple patch adds support for raid6 to the ORE.
Most operations and calculations where already for the general
case. Only things left:
* call async_gen_syndrome() in the case of raid6
(NOTE that the raid6 math is the one supported by the Linux Kernel
see: crypto/async_tx/async_pq.c)
* call _ore_add_parity_unit() twice with only last call generating
the redundancy pages.
* Fix couple BUGS in old code
a. In reads when parity==2 it can happen that per_dev->length=0
but per_dev->offset was set and adjusted by _ore_add_sg_seg().
Don't let it be overwritten.
b. The all 'cur_comp > starting_dev' thing to determine if:
"per_dev->offset is in the current stripe number or the
next one."
Was a complete raid5/4 accident. When parity==2 this is not
at all true usually. All we need to do is increment si->ob_offset
once we pass by the first parity device.
(This also greatly simplifies the code, amen)
c. Calculation of si->dev rotation can overflow when parity==2.
* Then last enable raid6 in ore_verify_layout()
I want to deeply thank Daniel Gryniewicz who found first all the
bugs in the old raid code, and inspired these patches:
Inspired-by Daniel Gryniewicz <dang@linuxbox.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
15 lines
495 B
Plaintext
15 lines
495 B
Plaintext
# ORE - Objects Raid Engine (libore.ko)
|
|
#
|
|
# Note ORE needs to "select ASYNC_XOR". So Not to force multiple selects
|
|
# for every ORE user we do it like this. Any user should add itself here
|
|
# at the "depends on EXOFS_FS || ..." with an ||. The dependencies are
|
|
# selected here, and we default to "ON". So in effect it is like been
|
|
# selected by any of the users.
|
|
config ORE
|
|
tristate
|
|
depends on EXOFS_FS || PNFS_OBJLAYOUT
|
|
select ASYNC_XOR
|
|
select RAID6_PQ
|
|
select ASYNC_PQ
|
|
default SCSI_OSD_ULD
|