[BP] MB-18158 Use old file's version info during the migration of KVS…

… header info

- When we read KVS header info from the old file, we should use the old
file's version info, not the latest magic.

- As Sherlock branch uses the oldest magic number (MAGIC_000), we get
rid of the code block that denies opening old files.

Change-Id: I322309c0993e2d1fada9fdfb81b79be5a9c52630

src/filemgr.cc

@@ -399,15 +399,6 @@ static fdb_status _filemgr_read_header(struct filemgr *file,
 
                 if (ver_is_valid_magic(magic)) {
 
-                    if (ver_is_magic_000(magic)) {
-                        // Deny MAGIC_000 file as it doesn't have any version info
-                        status = FDB_RESULT_FILE_VERSION_NOT_SUPPORTED;
-                        const char *msg = "Denied reading a database file '%s': "
-                            "too old version\n";
-                        fdb_log(log_callback, status, msg, file->filename);
-                        break;
-                    }
-
                     memcpy(&len,
                            buf + file->blocksize - BLK_MARKER_SIZE -
                            sizeof(magic) - sizeof(len),
@@ -434,7 +425,7 @@ static fdb_status _filemgr_read_header(struct filemgr *file,
                         } else {
                             status = FDB_RESULT_SUCCESS;
 
-                            file->header.data = (void *)malloc(len);
+                            file->header.data = (void *)malloc(file->blocksize);
 
                             memcpy(file->header.data, buf, len);
                             memcpy(&file->header.revnum, buf + len,
@@ -923,9 +914,7 @@ uint64_t filemgr_update_header(struct filemgr *file, void *buf, size_t len)
     spin_lock(&file->lock);
 
     if (file->header.data == NULL) {
-        file->header.data = (void *)malloc(len);
-    }else if (file->header.size < len){
-        file->header.data = (void *)realloc(file->header.data, len);
+        file->header.data = (void *)malloc(file->blocksize);
     }
     memcpy(file->header.data, buf, len);
     file->header.size = len;
@@ -2263,7 +2252,7 @@ char *filemgr_redirect_old_file(struct filemgr *very_old_file,
     // very_old_file, maybe reallocate DB header buf to accomodate bigger value
     if (new_header_len > old_header_len) {
         very_old_file->header.data = realloc(very_old_file->header.data,
-                new_header_len);
+                new_file->blocksize);
     }
     very_old_file->new_file = new_file; // Re-direct very_old_file to new_file
     past_filename = redirect_header_func(very_old_file,

src/kv_instance.cc

@@ -590,7 +590,7 @@ void fdb_kvs_header_copy(fdb_kvs_handle *handle,
         _fdb_kvs_header_create(&kv_header);
         // read from 'handle->dhandle', and import into 'new_file'
         fdb_kvs_header_read(kv_header, handle->dhandle,
-                            handle->kv_info_offset, ver_get_latest_magic(), false);
+                            handle->kv_info_offset, handle->file->version, false);
 
         // write KV header in 'new_file' using 'new_dhandle'
         uint64_t new_kv_info_offset;

src/version.cc

@@ -83,7 +83,7 @@ size_t ver_get_last_wal_flush_hdr_off(filemgr_magic_t magic) {
 const char* ver_get_version_string(filemgr_magic_t magic) {
     switch (magic) {
     case FILEMGR_MAGIC_000:
-        return "ForestDB pre-v1.x format";
+        return "ForestDB v1.x format";
     case FILEMGR_MAGIC_001:
         return "ForestDB v1.x format";
     case FILEMGR_MAGIC_002:

tests/anomaly/fdb_anomaly_test.cc

@@ -783,8 +783,11 @@ void read_old_file()
 
     // reopen
     s = fdb_open(&dbfile, "anomaly_test1", &config);
-    // should return version error
-    TEST_CHK(s == FDB_RESULT_FILE_VERSION_NOT_SUPPORTED);
+    // successfully read
+    TEST_CHK(s == FDB_RESULT_SUCCESS);
+
+    s = fdb_close(dbfile);
+    TEST_CHK(s == FDB_RESULT_SUCCESS);
 
     s = fdb_shutdown();
     memleak_end();