Fix nasty rebuild bug where partiy would be reconstructed incorrectly

when both data and parity was missing.  The fix is to just call decode
when reconstructing parity, since it will have to do extra work anyway
when data is missing.  We did a little extra work in ISA-L to do better,
but can save that for later, since 99% of the time decode will perform just
fine.

2 files changed, 72 insertions, 44 deletions

diff --git a/src/backends/jerasure/jerasure_rs_cauchy.c b/src/backends/jerasure/jerasure_rs_cauchy.c
index 4728a14..307dbe9 100644
--- a/src/backends/jerasure/jerasure_rs_cauchy.c
+++ b/src/backends/jerasure/jerasure_rs_cauchy.c
@@ -137,7 +137,7 @@ static int jerasure_rs_cauchy_reconstruct(void *desc, char **data, char **parity
         int *missing_idxs, int destination_idx, int blocksize)
 {
     int k, m, w;                  /* erasure code paramters */
-    int ret = 1;                  /* return code */
+    int ret = 0;                  /* return code */
     int *decoding_row = NULL;     /* decoding matrix row for decode */
     int *erased = NULL;           /* k+m length list of erased frag ids */
     int *dm_ids = NULL;           /* k length list of fragment ids */
@@ -149,29 +149,46 @@ static int jerasure_rs_cauchy_reconstruct(void *desc, char **data, char **parity
     m = jerasure_desc->m;
     w = jerasure_desc->w;
 
-    dm_ids = (int *) alloc_zeroed_buffer(sizeof(int) * k);
-    decoding_matrix = (int *) alloc_zeroed_buffer(sizeof(int *) * k * k * w * w);
-    erased = jerasure_desc->jerasure_erasures_to_erased(k, m, missing_idxs);
-    if (NULL == decoding_matrix || NULL == dm_ids || NULL == erased) {
-        goto out;
-    }
+    if (destination_idx < k) {
+        dm_ids = (int *) alloc_zeroed_buffer(sizeof(int) * k);
+        decoding_matrix = (int *) alloc_zeroed_buffer(sizeof(int *) * k * k * w * w);
+        erased = jerasure_desc->jerasure_erasures_to_erased(k, m, missing_idxs);
+        if (NULL == decoding_matrix || NULL == dm_ids || NULL == erased) {
+            goto out;
+        }
 
-    ret = jerasure_desc->jerasure_make_decoding_bitmatrix(k, m, w, 
+        ret = jerasure_desc->jerasure_make_decoding_bitmatrix(k, m, w, 
                                                jerasure_desc->bitmatrix,
                                                erased, decoding_matrix, dm_ids);
-    if (destination_idx < k) {
-        decoding_row = decoding_matrix + (destination_idx * k * w * w);
-    } else {
-        decoding_row = jerasure_desc->bitmatrix + ((destination_idx - k) * k * w * w);
-    }
+        if (ret == 0) {
+            decoding_row = decoding_matrix + (destination_idx * k * w * w);
    
-    if (ret == 0) {
-        jerasure_desc->jerasure_bitmatrix_dotprod(jerasure_desc->k, jerasure_desc->w, 
+            jerasure_desc->jerasure_bitmatrix_dotprod(jerasure_desc->k, jerasure_desc->w, 
                                    decoding_row, dm_ids, destination_idx,
-                                   data, parity, blocksize,
-                                   PYECC_CAUCHY_PACKETSIZE);
+                                   data, parity, blocksize, PYECC_CAUCHY_PACKETSIZE);
+        } else {
+           /*
+            * ToDo (KMG) I know this is not needed, but keeping to prevent future 
+            * memory leaks, as this function will be better optimized for decoding 
+            * missing parity 
+            */
+            goto out;
+        }
     } else {
-      goto out;
+        /*
+         * If it is parity we are reconstructing, then just call decode.
+         * ToDo (KMG): We can do better than this, but this should perform just
+         * fine for most cases.  We can adjust the decoding matrix like we
+         * did with ISA-L.
+         */
+        jerasure_desc->jerasure_bitmatrix_decode(k, m, w,
+                                             jerasure_desc->bitmatrix, 
+                                             0, 
+                                             missing_idxs,
+                                             data, 
+                                             parity, 
+                                             blocksize, 
+                                             PYECC_CAUCHY_PACKETSIZE); 
     }
 
 out:
diff --git a/src/backends/jerasure/jerasure_rs_vand.c b/src/backends/jerasure/jerasure_rs_vand.c
index 803bd95..ea2a846 100644
--- a/src/backends/jerasure/jerasure_rs_vand.c
+++ b/src/backends/jerasure/jerasure_rs_vand.c
@@ -108,7 +108,7 @@ static int jerasure_rs_vand_decode(void *desc, char **data, char **parity,
 static int jerasure_rs_vand_reconstruct(void *desc, char **data, char **parity,
         int *missing_idxs, int destination_idx, int blocksize)
 {
-    int ret = 1;                  /* return code */
+    int ret = 0;                  /* return code */
     int *decoding_row;            /* decoding matrix row for decode */
     int *erased = NULL;           /* k+m length list of erased frag ids */
     int *dm_ids = NULL;           /* k length list of frag ids */
@@ -117,35 +117,45 @@ static int jerasure_rs_vand_reconstruct(void *desc, char **data, char **parity,
     struct jerasure_rs_vand_descriptor *jerasure_desc = 
         (struct jerasure_rs_vand_descriptor*) desc;
     
-    dm_ids = (int *) alloc_zeroed_buffer(sizeof(int) * jerasure_desc->k);
-    decoding_matrix = (int *)
-        alloc_zeroed_buffer(sizeof(int*) * jerasure_desc->k * jerasure_desc->k);
-    if (NULL == decoding_matrix || NULL == dm_ids) {
-        goto out;
-    }
-    
-    erased = jerasure_desc->jerasure_erasures_to_erased(jerasure_desc->k,
-            jerasure_desc->m, missing_idxs);
-    if (NULL == erased) {
-        goto out;
-    }
-
-    ret = jerasure_desc->jerasure_make_decoding_matrix(jerasure_desc->k,
-            jerasure_desc->m, jerasure_desc->w, jerasure_desc->matrix,
-            erased, decoding_matrix, dm_ids);
     if (destination_idx < jerasure_desc->k) {
+        dm_ids = (int *) alloc_zeroed_buffer(sizeof(int) * jerasure_desc->k);
+        decoding_matrix = (int *)
+            alloc_zeroed_buffer(sizeof(int*) * jerasure_desc->k * jerasure_desc->k);
+        erased = jerasure_desc->jerasure_erasures_to_erased(jerasure_desc->k,
+                jerasure_desc->m, missing_idxs);
+        if (NULL == decoding_matrix || NULL == dm_ids || NULL == erased) {
+            goto out;
+        }
+
+        ret = jerasure_desc->jerasure_make_decoding_matrix(jerasure_desc->k,
+                jerasure_desc->m, jerasure_desc->w, jerasure_desc->matrix,
+                erased, decoding_matrix, dm_ids);
+
         decoding_row = decoding_matrix + (destination_idx * jerasure_desc->k);
-    } else {
-        decoding_row = jerasure_desc->matrix +
-            ((destination_idx - jerasure_desc->k) * jerasure_desc->k);
-    }
     
-    if (ret == 0) {
-        jerasure_desc->jerasure_matrix_dotprod(jerasure_desc->k,
-                jerasure_desc->w, decoding_row, dm_ids, destination_idx,
-                data, parity, blocksize);
+        if (ret == 0) {
+            jerasure_desc->jerasure_matrix_dotprod(jerasure_desc->k,
+                    jerasure_desc->w, decoding_row, dm_ids, destination_idx,
+                    data, parity, blocksize);
+        } else {
+            /*
+             * ToDo (KMG) I know this is not needed, but keeping to prevent future 
+             *  memory leaks, as this function will be better optimized for decoding 
+             * missing parity 
+             */
+            goto out;
+        }
     } else {
-      goto out;
+        /*
+         * If it is parity we are reconstructing, then just call decode.
+         * ToDo (KMG): We can do better than this, but this should perform just
+         * fine for most cases.  We can adjust the decoding matrix like we
+         * did with ISA-L.
+         */
+        jerasure_desc->jerasure_matrix_decode(jerasure_desc->k,
+                        jerasure_desc->m, jerasure_desc->w,
+                        jerasure_desc->matrix, 1, missing_idxs, data, parity, blocksize);
+        goto parity_reconstr_out;
     }
 
 out:
@@ -153,6 +163,7 @@ out:
     free(decoding_matrix);
     free(dm_ids);
 
+parity_reconstr_out:
     return ret;
 }