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| author | Boaz Harrosh <bharrosh@panasas.com> | 2014-05-22 14:48:15 +0300 |
|---|---|---|
| committer | Boaz Harrosh <bharrosh@panasas.com> | 2014-05-22 14:48:15 +0300 |
| commit | ce5d36aac26cc395fe3bc45525cdbad3644f01e5 (patch) | |
| tree | 04aa541850b8282baf000657307c6504d16c52ab /fs/exofs/Kconfig.ore | |
| parent | 455682ce547817d75e38028283dc8db00754005d (diff) | |
| download | linux-ce5d36aac26cc395fe3bc45525cdbad3644f01e5.tar.gz linux-ce5d36aac26cc395fe3bc45525cdbad3644f01e5.tar.bz2 linux-ce5d36aac26cc395fe3bc45525cdbad3644f01e5.zip | |
ore: Support for raid 6
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>
Diffstat (limited to 'fs/exofs/Kconfig.ore')
| -rw-r--r-- | fs/exofs/Kconfig.ore | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/exofs/Kconfig.ore b/fs/exofs/Kconfig.ore index 1ca7fb7b6ba8..2daf2329c28d 100644 --- a/fs/exofs/Kconfig.ore +++ b/fs/exofs/Kconfig.ore @@ -9,4 +9,6 @@ config ORE tristate depends on EXOFS_FS || PNFS_OBJLAYOUT select ASYNC_XOR + select RAID6_PQ + select ASYNC_PQ default SCSI_OSD_ULD |