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>
62 lines
2.2 KiB
C
62 lines
2.2 KiB
C
/*
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* Copyright (C) from 2011
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* Boaz Harrosh <bharrosh@panasas.com>
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*
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* This file is part of the objects raid engine (ore).
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*
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* It is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* You should have received a copy of the GNU General Public License
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* along with "ore". If not, write to the Free Software Foundation, Inc:
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* "Free Software Foundation <info@fsf.org>"
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*/
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#include <scsi/osd_ore.h>
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#define ORE_ERR(fmt, a...) printk(KERN_ERR "ore: " fmt, ##a)
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#ifdef CONFIG_EXOFS_DEBUG
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#define ORE_DBGMSG(fmt, a...) \
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printk(KERN_NOTICE "ore @%s:%d: " fmt, __func__, __LINE__, ##a)
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#else
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#define ORE_DBGMSG(fmt, a...) \
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do { if (0) printk(fmt, ##a); } while (0)
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#endif
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/* u64 has problems with printk this will cast it to unsigned long long */
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#define _LLU(x) (unsigned long long)(x)
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#define ORE_DBGMSG2(M...) do {} while (0)
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/* #define ORE_DBGMSG2 ORE_DBGMSG */
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/* ios_raid.c stuff needed by ios.c */
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int _ore_post_alloc_raid_stuff(struct ore_io_state *ios);
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void _ore_free_raid_stuff(struct ore_io_state *ios);
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void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
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bool not_last);
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int _ore_add_parity_unit(struct ore_io_state *ios, struct ore_striping_info *si,
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struct ore_per_dev_state *per_dev, unsigned cur_len,
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bool do_xor);
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void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d,
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struct ore_striping_info *si, struct page *page);
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static inline void _add_stripe_page(struct __stripe_pages_2d *sp2d,
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struct ore_striping_info *si, struct page *page)
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{
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if (!sp2d) /* Inline the fast path */
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return; /* Hay no raid stuff */
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_ore_add_stripe_page(sp2d, si, page);
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}
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/* ios.c stuff needed by ios_raid.c */
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int _ore_get_io_state(struct ore_layout *layout,
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struct ore_components *oc, unsigned numdevs,
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unsigned sgs_per_dev, unsigned num_par_pages,
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struct ore_io_state **pios);
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int _ore_add_stripe_unit(struct ore_io_state *ios, unsigned *cur_pg,
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unsigned pgbase, struct page **pages,
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struct ore_per_dev_state *per_dev, int cur_len);
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int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp);
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int ore_io_execute(struct ore_io_state *ios);
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