diff options
Diffstat (limited to 'fs/exofs/ore_raid.c')
| -rw-r--r-- | fs/exofs/ore_raid.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/fs/exofs/ore_raid.c b/fs/exofs/ore_raid.c new file mode 100644 index 000000000000..8d4b93a93c67 --- /dev/null +++ b/fs/exofs/ore_raid.c @@ -0,0 +1,140 @@ +/* + * Copyright (C) 2011 + * Boaz Harrosh <bharrosh@panasas.com> + * + * This file is part of the objects raid engine (ore). + * + * It is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * You should have received a copy of the GNU General Public License + * along with "ore". If not, write to the Free Software Foundation, Inc: + * "Free Software Foundation <info@fsf.org>" + */ + +#include <linux/gfp.h> + +#include "ore_raid.h" + +struct page *_raid_page_alloc(void) +{ + return alloc_page(GFP_KERNEL); +} + +void _raid_page_free(struct page *p) +{ + __free_page(p); +} + +void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len, + bool not_last) +{ + struct osd_sg_entry *sge; + + ORE_DBGMSG("dev=%d cur_len=0x%x not_last=%d cur_sg=%d " + "offset=0x%llx length=0x%x last_sgs_total=0x%x\n", + per_dev->dev, cur_len, not_last, per_dev->cur_sg, + _LLU(per_dev->offset), per_dev->length, + per_dev->last_sgs_total); + + if (!per_dev->cur_sg) { + sge = per_dev->sglist; + + /* First time we prepare two entries */ + if (per_dev->length) { + ++per_dev->cur_sg; + sge->offset = per_dev->offset; + sge->len = per_dev->length; + } else { + /* Here the parity is the first unit of this object. + * This happens every time we reach a parity device on + * the same stripe as the per_dev->offset. We need to + * just skip this unit. + */ + per_dev->offset += cur_len; + return; + } + } else { + /* finalize the last one */ + sge = &per_dev->sglist[per_dev->cur_sg - 1]; + sge->len = per_dev->length - per_dev->last_sgs_total; + } + + if (not_last) { + /* Partly prepare the next one */ + struct osd_sg_entry *next_sge = sge + 1; + + ++per_dev->cur_sg; + next_sge->offset = sge->offset + sge->len + cur_len; + /* Save cur len so we know how mutch was added next time */ + per_dev->last_sgs_total = per_dev->length; + next_sge->len = 0; + } else if (!sge->len) { + /* Optimize for when the last unit is a parity */ + --per_dev->cur_sg; + } +} + +/* In writes @cur_len means length left. .i.e cur_len==0 is the last parity U */ +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) +{ + if (ios->reading) { + BUG_ON(per_dev->cur_sg >= ios->sgs_per_dev); + _ore_add_sg_seg(per_dev, cur_len, true); + } else { + struct page **pages = ios->parity_pages + ios->cur_par_page; + unsigned num_pages = ios->layout->stripe_unit / PAGE_SIZE; + unsigned array_start = 0; + unsigned i; + int ret; + + for (i = 0; i < num_pages; i++) { + pages[i] = _raid_page_alloc(); + if (unlikely(!pages[i])) + return -ENOMEM; + + ++(ios->cur_par_page); + /* TODO: only read support for now */ + clear_highpage(pages[i]); + } + + ORE_DBGMSG("writing dev=%d num_pages=%d cur_par_page=%d", + per_dev->dev, num_pages, ios->cur_par_page); + + ret = _ore_add_stripe_unit(ios, &array_start, 0, pages, + per_dev, num_pages * PAGE_SIZE); + if (unlikely(ret)) + return ret; + } + return 0; +} + +int _ore_post_alloc_raid_stuff(struct ore_io_state *ios) +{ + /*TODO: Only raid writes has stuff to add here */ + return 0; +} + +void _ore_free_raid_stuff(struct ore_io_state *ios) +{ + if (ios->parity_pages) { /* writing and raid */ + unsigned i; + + for (i = 0; i < ios->cur_par_page; i++) { + struct page *page = ios->parity_pages[i]; + + if (page) + _raid_page_free(page); + } + if (ios->extra_part_alloc) + kfree(ios->parity_pages); + } else { + /* Will only be set if raid reading && sglist is big */ + if (ios->extra_part_alloc) + kfree(ios->per_dev[0].sglist); + } +} |