/sys/src/cmd/fossil/cache.c
% cat >/sys/lib/dist/changes/1176501605.6.txt << EOF
We know that the I/O error is in reading, so we should specify so.
EOF
 [geoff] --rw-rw-r-- M 121 rsc sys 43930 Apr 13 17:36 sys/src/cmd/fossil/cache.c
	/n/sourcesdump/2007/0413/plan9/sys/src/cmd/fossil/cache.c:462,468 - 
	/n/sources/plan9/sys/src/cmd/fossil/cache.c:462,468
	  			return nil;
	  		case BioReadError:
	  			blockPut(b);
	- 			vtSetError("i/o error block 0x%.8ux", addr);
	+ 			vtSetError("error reading block 0x%.8ux", addr);
	  			return nil;
	  		}
	  	}
	/n/sourcesdump/2007/0413/plan9/sys/src/cmd/fossil/cache.c:577,583 - 
	/n/sources/plan9/sys/src/cmd/fossil/cache.c:577,583
	  		case BioReadError:
	  			blockSetIOState(b, BioEmpty);
	  			blockPut(b);
	- 			vtSetError("i/o error block 0x%.8ux", addr);
	+ 			vtSetError("error reading block 0x%.8ux", addr);
	  			return nil;
	  		}
	  	}
	/n/sourcesdump/2007/0413/plan9/sys/src/cmd/fossil/cache.c:681,687 - 
	/n/sources/plan9/sys/src/cmd/fossil/cache.c:681,689
	  		if(n < 0 || !vtSha1Check(score, b->data, n)){
	  			blockSetIOState(b, BioVentiError);
	  			blockPut(b);
	- 			vtSetError("venti i/o error block %V: %r", score);
	+ 			vtSetError(
	+ 			"venti error reading block %V or wrong score: %r",
	+ 				score);
	  			return nil;
	  		}
	  		vtZeroExtend(vtType[type], b->data, n, c->size);
	/n/sourcesdump/2007/0413/plan9/sys/src/cmd/fossil/cache.c:691,701 - 
	/n/sources/plan9/sys/src/cmd/fossil/cache.c:693,703
	  		return b;
	  	case BioVentiError:
	  		blockPut(b);
	- 		vtSetError("venti i/o error block %V", score);
	+ 		vtSetError("venti i/o error or wrong score, block %V", score);
	  		return nil;
	  	case BioReadError:
	  		blockPut(b);
	- 		vtSetError("i/o error block %V", b->score);
	+ 		vtSetError("error reading block %V", b->score);
	  		return nil;
	  	}
	  	/* NOT REACHED */