From ce5d36aac26cc395fe3bc45525cdbad3644f01e5 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Thu, 22 May 2014 14:48:15 +0300 Subject: 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 Signed-off-by: Boaz Harrosh --- fs/exofs/ore_raid.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/exofs/ore_raid.h') diff --git a/fs/exofs/ore_raid.h b/fs/exofs/ore_raid.h index d365bda6beef..cf6375d82129 100644 --- a/fs/exofs/ore_raid.h +++ b/fs/exofs/ore_raid.h @@ -38,7 +38,8 @@ void _ore_free_raid_stuff(struct ore_io_state *ios); void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len, bool not_last); int _ore_add_parity_unit(struct ore_io_state *ios, struct ore_striping_info *si, - struct ore_per_dev_state *per_dev, unsigned cur_len); + struct ore_per_dev_state *per_dev, unsigned cur_len, + bool do_xor); void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d, struct ore_striping_info *si, struct page *page); static inline void _add_stripe_page(struct __stripe_pages_2d *sp2d, -- cgit v1.2.3