async_tx: fix asynchronous raid6 recovery for ddf layouts
The raid6 recovery code currently requires special handling of the
4-disk and 5-disk recovery scenarios for the native layout. Quoting
from commit 0a82a623:
In these situations the default N-disk algorithm will present
0-source or 1-source operations to dma devices. To cover for
dma devices where the minimum source count is 2 we implement
4-disk and 5-disk handling in the recovery code.
The ddf layout presents disks=6 and disks=7 to the recovery code in
these situations. Instead of looking at the number of disks count the
number of non-zero sources in the list and call the special case code
when the number of non-failed sources is 0 or 1.
[neilb@suse.de: replace 'ddf' flag with counting good sources]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 8e30b6e..943f2ab 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -131,8 +131,8 @@
}
static struct dma_async_tx_descriptor *
-__2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
- struct async_submit_ctl *submit)
+__2data_recov_4(int disks, size_t bytes, int faila, int failb,
+ struct page **blocks, struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *a, *b;
@@ -143,8 +143,8 @@
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
- p = blocks[4-2];
- q = blocks[4-1];
+ p = blocks[disks-2];
+ q = blocks[disks-1];
a = blocks[faila];
b = blocks[failb];
@@ -170,8 +170,8 @@
}
static struct dma_async_tx_descriptor *
-__2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks,
- struct async_submit_ctl *submit)
+__2data_recov_5(int disks, size_t bytes, int faila, int failb,
+ struct page **blocks, struct async_submit_ctl *submit)
{
struct dma_async_tx_descriptor *tx = NULL;
struct page *p, *q, *g, *dp, *dq;
@@ -181,21 +181,22 @@
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
- int uninitialized_var(good);
- int i;
+ int good_srcs, good, i;
- for (i = 0; i < 3; i++) {
+ good_srcs = 0;
+ good = -1;
+ for (i = 0; i < disks-2; i++) {
+ if (blocks[i] == NULL)
+ continue;
if (i == faila || i == failb)
continue;
- else {
- good = i;
- break;
- }
+ good = i;
+ good_srcs++;
}
- BUG_ON(i >= 3);
+ BUG_ON(good_srcs > 1);
- p = blocks[5-2];
- q = blocks[5-1];
+ p = blocks[disks-2];
+ q = blocks[disks-1];
g = blocks[good];
/* Compute syndrome with zero for the missing data pages
@@ -323,6 +324,8 @@
async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
struct page **blocks, struct async_submit_ctl *submit)
{
+ int non_zero_srcs, i;
+
BUG_ON(faila == failb);
if (failb < faila)
swap(faila, failb);
@@ -334,12 +337,11 @@
*/
if (!submit->scribble) {
void **ptrs = (void **) blocks;
- int i;
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
if (blocks[i] == NULL)
- ptrs[i] = (void*)raid6_empty_zero_page;
+ ptrs[i] = (void *) raid6_empty_zero_page;
else
ptrs[i] = page_address(blocks[i]);
@@ -350,19 +352,30 @@
return NULL;
}
- switch (disks) {
- case 4:
+ non_zero_srcs = 0;
+ for (i = 0; i < disks-2 && non_zero_srcs < 4; i++)
+ if (blocks[i])
+ non_zero_srcs++;
+ switch (non_zero_srcs) {
+ case 0:
+ case 1:
+ /* There must be at least 2 sources - the failed devices. */
+ BUG();
+
+ case 2:
/* dma devices do not uniformly understand a zero source pq
* operation (in contrast to the synchronous case), so
- * explicitly handle the 4 disk special case
+ * explicitly handle the special case of a 4 disk array with
+ * both data disks missing.
*/
- return __2data_recov_4(bytes, faila, failb, blocks, submit);
- case 5:
+ return __2data_recov_4(disks, bytes, faila, failb, blocks, submit);
+ case 3:
/* dma devices do not uniformly understand a single
* source pq operation (in contrast to the synchronous
- * case), so explicitly handle the 5 disk special case
+ * case), so explicitly handle the special case of a 5 disk
+ * array with 2 of 3 data disks missing.
*/
- return __2data_recov_5(bytes, faila, failb, blocks, submit);
+ return __2data_recov_5(disks, bytes, faila, failb, blocks, submit);
default:
return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
}
@@ -388,6 +401,7 @@
dma_async_tx_callback cb_fn = submit->cb_fn;
void *cb_param = submit->cb_param;
void *scribble = submit->scribble;
+ int good_srcs, good, i;
struct page *srcs[2];
pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
@@ -397,7 +411,6 @@
*/
if (!scribble) {
void **ptrs = (void **) blocks;
- int i;
async_tx_quiesce(&submit->depend_tx);
for (i = 0; i < disks; i++)
@@ -413,6 +426,20 @@
return NULL;
}
+ good_srcs = 0;
+ good = -1;
+ for (i = 0; i < disks-2; i++) {
+ if (i == faila)
+ continue;
+ if (blocks[i]) {
+ good = i;
+ good_srcs++;
+ if (good_srcs > 1)
+ break;
+ }
+ }
+ BUG_ON(good_srcs == 0);
+
p = blocks[disks-2];
q = blocks[disks-1];
@@ -423,11 +450,10 @@
blocks[faila] = NULL;
blocks[disks-1] = dq;
- /* in the 4 disk case we only need to perform a single source
- * multiplication
+ /* in the 4-disk case we only need to perform a single source
+ * multiplication with the one good data block.
*/
- if (disks == 4) {
- int good = faila == 0 ? 1 : 0;
+ if (good_srcs == 1) {
struct page *g = blocks[good];
init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
