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authorBoaz Harrosh <bharrosh@panasas.com>2014-05-22 15:48:15 +0400
committerBoaz Harrosh <bharrosh@panasas.com>2014-05-22 15:48:15 +0400
commitce5d36aac26cc395fe3bc45525cdbad3644f01e5 (patch)
tree04aa541850b8282baf000657307c6504d16c52ab /fs/exofs/ore_raid.c
parent455682ce547817d75e38028283dc8db00754005d (diff)
downloadlinux-ce5d36aac26cc395fe3bc45525cdbad3644f01e5.tar.xz
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/ore_raid.c')
-rw-r--r--fs/exofs/ore_raid.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/fs/exofs/ore_raid.c b/fs/exofs/ore_raid.c
index d58a952e28bc..7f20f25c232c 100644
--- a/fs/exofs/ore_raid.c
+++ b/fs/exofs/ore_raid.c
@@ -218,20 +218,28 @@ static unsigned _sp2d_max_pg(struct __stripe_pages_2d *sp2d)
static void _gen_xor_unit(struct __stripe_pages_2d *sp2d)
{
unsigned p;
+ unsigned tx_flags = ASYNC_TX_ACK;
+
+ if (sp2d->parity == 1)
+ tx_flags |= ASYNC_TX_XOR_ZERO_DST;
+
for (p = 0; p < sp2d->pages_in_unit; p++) {
struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
if (!_1ps->write_count)
continue;
- init_async_submit(&_1ps->submit,
- ASYNC_TX_XOR_ZERO_DST | ASYNC_TX_ACK,
+ init_async_submit(&_1ps->submit, tx_flags,
NULL, NULL, NULL, (addr_conv_t *)_1ps->scribble);
- /* TODO: raid6 */
- _1ps->tx = async_xor(_1ps->pages[sp2d->data_devs], _1ps->pages,
- 0, sp2d->data_devs, PAGE_SIZE,
- &_1ps->submit);
+ if (sp2d->parity == 1)
+ _1ps->tx = async_xor(_1ps->pages[sp2d->data_devs],
+ _1ps->pages, 0, sp2d->data_devs,
+ PAGE_SIZE, &_1ps->submit);
+ else /* parity == 2 */
+ _1ps->tx = async_gen_syndrome(_1ps->pages, 0,
+ sp2d->data_devs + sp2d->parity,
+ PAGE_SIZE, &_1ps->submit);
}
for (p = 0; p < sp2d->pages_in_unit; p++) {
@@ -616,7 +624,7 @@ static int _read_4_write_execute(struct ore_io_state *ios)
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)
+ unsigned cur_len, bool do_xor)
{
if (ios->reading) {
if (per_dev->cur_sg >= ios->sgs_per_dev) {
@@ -641,9 +649,11 @@ int _ore_add_parity_unit(struct ore_io_state *ios,
/* If first stripe, Read in all read4write pages
* (if needed) before we calculate the first parity.
*/
- _read_4_write_first_stripe(ios);
+ if (do_xor)
+ _read_4_write_first_stripe(ios);
}
- if (!cur_len) /* If last stripe r4w pages of last stripe */
+ if (!cur_len && do_xor)
+ /* If last stripe r4w pages of last stripe */
_read_4_write_last_stripe(ios);
_read_4_write_execute(ios);
@@ -655,7 +665,7 @@ int _ore_add_parity_unit(struct ore_io_state *ios,
++(ios->cur_par_page);
}
- BUG_ON(si->cur_comp != sp2d->data_devs);
+ BUG_ON(si->cur_comp < sp2d->data_devs);
BUG_ON(si->cur_pg + num_pages > sp2d->pages_in_unit);
ret = _ore_add_stripe_unit(ios, &array_start, 0, pages,
@@ -663,9 +673,10 @@ int _ore_add_parity_unit(struct ore_io_state *ios,
if (unlikely(ret))
return ret;
- /* TODO: raid6 if (last_parity_dev) */
- _gen_xor_unit(sp2d);
- _sp2d_reset(sp2d, ios->r4w, ios->private);
+ if (do_xor) {
+ _gen_xor_unit(sp2d);
+ _sp2d_reset(sp2d, ios->r4w, ios->private);
+ }
}
return 0;
}