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-rw-r--r--xlators/cluster/dht/src/dht-selfheal.c82
1 files changed, 60 insertions, 22 deletions
diff --git a/xlators/cluster/dht/src/dht-selfheal.c b/xlators/cluster/dht/src/dht-selfheal.c
index 8463abdbfaf..77afde82e16 100644
--- a/xlators/cluster/dht/src/dht-selfheal.c
+++ b/xlators/cluster/dht/src/dht-selfheal.c
@@ -38,12 +38,20 @@ dht_overlap_calc (dht_layout_t *old, int o, dht_layout_t *new, int n)
if (old->list[o].err > 0 || new->list[n].err > 0)
return 0;
+ if (old->list[o].start == old->list[o].stop) {
+ return 0;
+ }
+
+ if (new->list[n].start == new->list[n].stop) {
+ return 0;
+ }
+
if ((old->list[o].start > new->list[n].stop) ||
(old->list[o].stop < new->list[n].start))
return 0;
- return max (old->list[o].start, new->list[n].start) -
- min (old->list[o].stop, new->list[n].stop);
+ return min (old->list[o].stop, new->list[n].stop) -
+ max (old->list[o].start, new->list[n].start) + 1;
}
@@ -564,18 +572,25 @@ void dht_selfheal_layout_new_directory (call_frame_t *frame, loc_t *loc,
dht_layout_t *new_layout);
void dht_layout_entry_swap (dht_layout_t *layout, int i, int j);
+void dht_layout_range_swap (dht_layout_t *layout, int i, int j);
+
+/*
+ * It's a bit icky using local variables in a macro, but it makes the rest
+ * of the code a lot clearer.
+ */
+#define OV_ENTRY(x,y) table[x*new->cnt+y]
void
dht_selfheal_layout_maximize_overlap (call_frame_t *frame, loc_t *loc,
dht_layout_t *new, dht_layout_t *old)
{
int i = 0;
- int k = 0;
+ int j = 0;
uint32_t curr_overlap = 0;
uint32_t max_overlap = 0;
int max_overlap_idx = -1;
uint32_t overlap = 0;
-
+ uint32_t *table = NULL;
dht_layout_sort_volname (old);
/* Now both old_layout->list[] and new_layout->list[]
@@ -584,31 +599,54 @@ dht_selfheal_layout_maximize_overlap (call_frame_t *frame, loc_t *loc,
to the same subvolumes
*/
+ /* Build a table of overlaps between new[i] and old[j]. */
+ table = alloca(sizeof(overlap)*old->cnt*new->cnt);
+ if (!table) {
+ return;
+ }
+ memset(table,0,sizeof(overlap)*new->cnt*new->cnt);
+ for (i = 0; i < new->cnt; ++i) {
+ for (j = 0; j < old->cnt; ++j) {
+ OV_ENTRY(i,j) = dht_overlap_calc(old,j,new,i);
+ }
+ }
+
for (i = 0; i < new->cnt; i++) {
- if (new->list[i].err > 0)
+ if (new->list[i].err > 0) {
/* Subvol might be marked for decommission
with EINVAL, or some other serious error
marked with positive errno.
*/
continue;
+ }
- curr_overlap = dht_overlap_calc (old, i, new, i);
- max_overlap = curr_overlap;
- max_overlap_idx = i;
-
- /* Subvols up to `i' have already found their best
- matches. Search only from the rest.
- */
- for (k = (i + 1); k < new->cnt; k++) {
- overlap = dht_overlap_calc (old, i, new, k);
- if (overlap > max_overlap) {
- max_overlap_idx = k;
- max_overlap = overlap;
- }
- }
-
- if (max_overlap > curr_overlap)
- dht_layout_entry_swap (new, i, max_overlap_idx);
+ max_overlap = 0;
+ max_overlap_idx = i;
+ for (j = (i + 1); j < new->cnt; ++j) {
+ /* Calculate the overlap now. */
+ curr_overlap = OV_ENTRY(i,i) + OV_ENTRY(j,j);
+ /* Calculate the overlap after the proposed swap. */
+ overlap = OV_ENTRY(i,j) + OV_ENTRY(j,i);
+ /* Are we better than status quo? */
+ if (overlap > curr_overlap) {
+ overlap -= curr_overlap;
+ /* Are we better than the previous choice? */
+ if (overlap > max_overlap) {
+ max_overlap = overlap;
+ max_overlap_idx = j;
+ }
+ }
+ }
+
+ if (max_overlap_idx != i) {
+ dht_layout_range_swap (new, i, max_overlap_idx);
+ /* Need to swap the table values too. */
+ for (j = 0; j < old->cnt; ++j) {
+ overlap = OV_ENTRY(i,j);
+ OV_ENTRY(i,j) = OV_ENTRY(max_overlap_idx,j);
+ OV_ENTRY(max_overlap_idx,j) = overlap;
+ }
+ }
}
}