restore: print expected lthash

Also fix a rare bug in io_wd that results in a false assertion
failure.

Author: riptl

src/discof/restore/fd_snapin_tile.c

@@ -396,6 +396,15 @@ process_manifest( fd_snapin_tile_t * ctx ) {
     return;
   }
 
+  if( manifest->has_accounts_lthash ) {
+    uchar const * sum = manifest->accounts_lthash;
+    uchar hash32[32]; fd_blake3_hash( sum, FD_LTHASH_LEN_BYTES, hash32 );
+    FD_BASE58_ENCODE_32_BYTES( sum,    sum_enc    );
+    FD_BASE58_ENCODE_32_BYTES( hash32, hash32_enc );
+    FD_LOG_NOTICE(( "Snapshot manifest slot=%lu indicates lthash[..32]=%s blake3(lthash)=%s",
+                    manifest->slot, sum_enc, hash32_enc ));
+  }
+
   manifest->txncache_fork_id = ctx->txncache_root_fork_id.val;
 
   ulong sig = ctx->full ? fd_ssmsg_sig( FD_SSMSG_MANIFEST_FULL ) :

src/discof/restore/utils/fd_vinyl_io_wd.c

@@ -73,7 +73,6 @@ wd_block_used( fd_vinyl_io_wd_t * wd ) {
   FD_CRIT( fd_vinyl_seq_ge( wd->base->seq_future, wd->base->seq_present ), "corrupt bstream io state" );
   ulong block_sz = wd->base->seq_future - buf->bstream_seq;
   FD_CRIT( block_sz<=wd->wr_mtu, "corrupt bstream io state" );
-  FD_CRIT( block_sz>0UL, "attempted to dispatch empty buf" );
   return block_sz;
 }
 
@@ -92,6 +91,7 @@ wd_dispatch( fd_vinyl_io_wd_t * wd ) {
   FD_CRIT( fd_vinyl_seq_ge( wd->base->seq_future, wd->base->seq_present ), "corrupt bstream io state" );
   ulong block_sz = wd_block_used( wd );
   FD_CRIT( fd_ulong_is_aligned( block_sz, FD_VINYL_BSTREAM_BLOCK_SZ ), "misaligned block_sz (bad appends?)" );
+  FD_CRIT( block_sz>0UL, "attempted to dispatch empty buf" );
 
   /* Align up block_sz to multiple of 4096 bytes.
      This step is critical for good O_DIRECT performance. */