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>
As Reported by Randy Dunlap
When MISC_FILESYSTEMS is not enabled and NFS4.1 is:
fs/built-in.o: In function `objio_alloc_io_state':
objio_osd.c:(.text+0xcb525): undefined reference to `ore_get_rw_state'
fs/built-in.o: In function `_write_done':
objio_osd.c:(.text+0xcb58d): undefined reference to `ore_check_io'
fs/built-in.o: In function `_read_done':
...
When MISC_FILESYSTEMS, which is more of a GUI thing then anything else,
is not selected. exofs/Kconfig is never examined during Kconfig,
and it can not do it's magic stuff to automatically select everything
needed.
We must split exofs/Kconfig in two. The ore one is always included.
And the exofs one is left in it's old place in the menu.
[Needed for the 3.2.0 Kernel]
CC: Stable Tree <stable@kernel.org>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
