Add optional fragment metadata check for decode

Signed-off-by: Tushar Gohad <tushar.gohad@intel.com>

4 files changed, 44 insertions, 19 deletions

diff --git a/include/erasurecode/erasurecode.h b/include/erasurecode/erasurecode.h
index d53f182..74f6385 100644
--- a/include/erasurecode/erasurecode.h
+++ b/include/erasurecode/erasurecode.h
@@ -169,6 +169,7 @@ int liberasurecode_encode_cleanup(int desc, char **encoded_data,
  * @param fragments - erasure encoded fragments (> = k)
  * @param num_fragments - number of fragments being passed in
  * @param fragment_len - length of each fragment (assume they are the same)
+ * @param force_metadata_checks - force fragment metadata checks (default: 0)
  * @param out_data - _output_ pointer to decoded data
  * @param out_data_len - _output_ length of decoded output
  *          (both output data pointers are allocated by liberasurecode,
@@ -180,6 +181,7 @@ int liberasurecode_encode_cleanup(int desc, char **encoded_data,
 int liberasurecode_decode(int desc,
         char **available_fragments,                     /* input */
         int num_fragments, uint64_t fragment_len,       /* input */
+        int force_metadata_checks,                      /* input */
         char **out_data, uint64_t *out_data_len);       /* output */
 
 /**
@@ -279,9 +281,9 @@ int liberasurecode_get_fragment_metadata(char *fragment,
 *        from liberasurecode_instance_create()
 * @param fragment - fragment to verify
 *
-* @return 0 if fragment validation is successful, 1 otherwise.
+* @return 1 if fragment validation fails, 0 otherwise.
 */
-int is_valid_fragment(int desc, char *fragment);
+int is_invalid_fragment(int desc, char *fragment);
 
 /**
  * Verify a subset of fragments generated by encode()
@@ -336,6 +338,7 @@ typedef enum {
     EBADCHKSUM       = 205,
     EINVALIDPARAMS   = 206,
     EBADHEADER       = 207,
+    EINSUFFFRAGS     = 208,
 } LIBERASURECODE_ERROR_CODES;
 
 /* =~=*=~==~=*=~==~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~===~=*=~==~=*=~= */
diff --git a/src/erasurecode.c b/src/erasurecode.c
index b4d9872..22aa2e8 100644
--- a/src/erasurecode.c
+++ b/src/erasurecode.c
@@ -495,6 +495,7 @@ int liberasurecode_decode_cleanup(int desc, char *data)
  * @param fragments - erasure encoded fragments (> = k)
  * @param num_fragments - number of fragments being passed in
  * @param fragment_len - length of each fragment (assume they are the same)
+ * @param force_metadata_checks - force fragment metadata checks (default: 0)
  * @param out_data - _output_ pointer to decoded data
  * @param out_data_len - _output_ length of decoded output
  * @return 0 on success, -error code otherwise
@@ -502,6 +503,7 @@ int liberasurecode_decode_cleanup(int desc, char *data)
 int liberasurecode_decode(int desc,
         char **available_fragments,                     /* input */
         int num_fragments, uint64_t fragment_len,       /* input */
+        int force_metadata_checks,                      /* input */
         char **out_data, uint64_t *out_data_len)        /* output */
 {
     int i, j;
@@ -546,6 +548,11 @@ int liberasurecode_decode(int desc,
     k = instance->args.uargs.k;
     m = instance->args.uargs.m;
 
+    if (num_fragments < k) {
+        ret = -EINSUFFFRAGS;
+        goto out;
+    }
+
     /*
      * Try to re-assebmle the original data before attempting a decode
      */
@@ -578,6 +585,21 @@ int liberasurecode_decode(int desc,
         log_error("Could not allocate missing_idxs buffer!");
         goto out;
     }
+
+    /* If metadata checks requested, check fragment integrity upfront */ 
+    if (force_metadata_checks) {
+        int num_invalid_fragments = 0;
+        for (i = 0; i < num_fragments; ++i) {
+            if (is_invalid_fragment(desc, available_fragments[i])) {
+                ++num_invalid_fragments;
+            }
+        }
+        if (num_invalid_fragments > (k - 1)) {
+            ret = -EINSUFFFRAGS;
+            log_error("Not enough valid fragments available for decode!");
+            goto out;
+        }
+    }
     
     /*
      * Separate the fragments into data and parity.  Also determine which
@@ -965,13 +987,13 @@ int liberasurecode_verify_fragment_metadata(ec_backend_t be,
     return 0;
 }
 
-int is_valid_fragment(int desc, char *fragment)
+int is_invalid_fragment(int desc, char *fragment)
 {
     uint32_t ver = 0;
     fragment_metadata_t fragment_metadata;
     ec_backend_t be = liberasurecode_backend_instance_get_by_desc(desc);
     if (!be) {
-        log_error("Unable to verify stripe metadata: invalid backend id %d.",
+        log_error("Unable to verify fragment metadata: invalid backend id %d.",
                 desc);
         return 1;
     }
diff --git a/test/libec_slap.c b/test/libec_slap.c
index f3166fe..0f3c24b 100644
--- a/test/libec_slap.c
+++ b/test/libec_slap.c
@@ -283,8 +283,8 @@ static int test_hd_code(struct ec_args *args,
         create_frags_array_set(&frags,encoded_data, args->k, encoded_parity,
                                args->m, mask);
         rc = liberasurecode_decode(desc, frags.array, frags.num_fragments,
-                                   encoded_fragment_len, &out_data,
-                                   &out_data_len);
+                                   encoded_fragment_len, 1,
+                                   &out_data, &out_data_len);
         assert(rc == 0);
         assert(out_data_len == blocksize * args->k);
         if (memcmp(data, out_data, out_data_len) != 0) {
@@ -308,8 +308,8 @@ static int test_hd_code(struct ec_args *args,
         create_frags_array_set(&frags,encoded_data, args->k, encoded_parity,
                                args->m, mask);
         rc = liberasurecode_decode(desc, frags.array, frags.num_fragments,
-                                   encoded_fragment_len, &out_data,
-                                   &out_data_len);
+                                   encoded_fragment_len, 1,
+                                   &out_data, &out_data_len);
         free(frags.array);
         free(out_data);
 
diff --git a/test/liberasurecode_test.c b/test/liberasurecode_test.c
index 49b70c6..b3c17df 100644
--- a/test/liberasurecode_test.c
+++ b/test/liberasurecode_test.c
@@ -346,23 +346,23 @@ static void test_decode_invalid_args()
                                          encoded_parity, &null_args, skips);
 
     rc = liberasurecode_decode(-1, avail_frags, num_avail_frags,
-                               encoded_fragment_len, &decoded_data,
-                               &decoded_data_len);
+                               encoded_fragment_len, 1,
+                               &decoded_data, &decoded_data_len);
     assert(rc < 0);
 
     rc = liberasurecode_decode(desc, NULL, num_avail_frags,
-                               encoded_fragment_len, &decoded_data,
-                               &decoded_data_len);
+                               encoded_fragment_len, 1,
+                               &decoded_data, &decoded_data_len);
     assert(rc < 0);
 
     rc = liberasurecode_decode(desc, avail_frags, num_avail_frags,
-                               encoded_fragment_len, NULL,
-                               &decoded_data_len);
+                               encoded_fragment_len, 1,
+                               NULL, &decoded_data_len);
     assert(rc < 0);
 
     rc = liberasurecode_decode(desc, avail_frags, num_avail_frags,
-                               encoded_fragment_len, &decoded_data,
-                               NULL);
+                               encoded_fragment_len, 1,
+                               &decoded_data, NULL);
     assert(rc < 0);
     free(skips);
     liberasurecode_encode_cleanup(desc, encoded_data, encoded_parity);
@@ -540,8 +540,8 @@ static void encode_decode_test_impl(const ec_backend_id_t be_id,
     assert(num_avail_frags != -1);
 
     rc = liberasurecode_decode(desc, avail_frags, num_avail_frags,
-                               encoded_fragment_len, &decoded_data,
-                               &decoded_data_len);
+                               encoded_fragment_len, 1,
+                               &decoded_data, &decoded_data_len);
     assert(0 == rc);
     assert(decoded_data_len == orig_data_size);
     assert(memcmp(decoded_data, orig_data, orig_data_size) == 0);
@@ -1002,7 +1002,7 @@ static void verify_fragment_metadata_mismatch_impl(const ec_backend_id_t be_id,
             default:
                 assert(false);
         }
-        rc = is_valid_fragment(desc, avail_frags[i]);
+        rc = is_invalid_fragment(desc, avail_frags[i]);
         assert(rc == 1);
         //heal fragment
         switch (scenario) {