btrfs-progs: scrub: show the scrubbing rate and estimated time to finish

The estimation is based on the allocated bytes, so it might be
overestimated.  Scrub reports the size of all bytes scrubbed, taking
into account the replication, so we're comparing that with total sum
over all devices that we get from DEV_INFO, in the same units.

Example output:

scrub status for xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
        scrub started at Fri May 31 15:56:57 2019, running for 0:04:31
        total 62.55GiB scrubbed at rate 236.37MiB/s, time left: 0:12:31
        no errors found

Pull-request: #177
Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
Signed-off-by: David Sterba <dsterba@suse.com>

cmds-scrub.c

@@ -134,10 +134,19 @@ static void print_scrub_full(struct btrfs_scrub_progress *sp)
 		printf(" %s=%llu", desc, test);	\
 } while (0)
 
-static void print_scrub_summary(struct btrfs_scrub_progress *p)
+static void print_scrub_summary(struct btrfs_scrub_progress *p, struct scrub_stats *s, u64 bytes_total)
 {
 	u64 err_cnt;
 	u64 err_cnt2;
+	u64 bytes_scrubbed;
+	u64 bytes_per_sec = 0;
+	u64 sec_left = 0;
+
+	bytes_scrubbed = p->data_bytes_scrubbed + p->tree_bytes_scrubbed;
+	if (s->duration > 0)
+		bytes_per_sec = bytes_scrubbed / s->duration;
+	if (bytes_per_sec > 0)
+		sec_left = (bytes_total - bytes_scrubbed) / bytes_per_sec;
 
 	err_cnt = p->read_errors +
 			p->csum_errors +
@@ -150,9 +159,18 @@ static void print_scrub_summary(struct btrfs_scrub_progress *p)
 		printf("*** WARNING: memory allocation failed while scrubbing. "
 		       "results may be inaccurate\n");
 
-	printf("\ttotal bytes scrubbed: %s with %llu errors\n",
-		pretty_size(p->data_bytes_scrubbed + p->tree_bytes_scrubbed),
-		max(err_cnt, err_cnt2));
+	if (s->in_progress) {
+		printf(
+		"\ttotal %s scrubbed at rate %s/s, time left: %llu:%02llu:%02llu\n",
+			pretty_size(bytes_scrubbed),
+			pretty_size(bytes_per_sec),
+			sec_left / 3600, (sec_left / 60) % 60, sec_left % 60);
+	} else {
+		printf("\ttotal %s scrubbed at rate %s/s\n",
+			pretty_size(bytes_scrubbed),
+			pretty_size(bytes_per_sec));
+	}
+
 
 	if (err_cnt || err_cnt2) {
 		printf("\terror details:");
@@ -164,6 +182,8 @@ static void print_scrub_summary(struct btrfs_scrub_progress *p)
 		printf("\tcorrected errors: %llu, uncorrectable errors: %llu, "
 			"unverified errors: %llu\n", p->corrected_errors,
 			p->uncorrectable_errors, p->unverified_errors);
+	} else {
+		printf("\tno errors found\n");
 	}
 }
 
@@ -251,13 +271,13 @@ static void _print_scrub_ss(struct scrub_stats *ss)
 	gmtime_r(&seconds, &tm);
 	strftime(t, sizeof(t), "%M:%S", &tm);
 	if (ss->in_progress)
-		printf(", running for %02u:%s\n", hours, t);
+		printf(", running for %u:%s\n", hours, t);
 	else if (ss->canceled)
-		printf(" and was aborted after %02u:%s\n", hours, t);
+		printf(" and was aborted after %u:%s\n", hours, t);
 	else if (ss->finished)
-		printf(" and finished after %02u:%s\n", hours, t);
+		printf(" and finished after %u:%s\n", hours, t);
 	else
-		printf(", interrupted after %02u:%s, not running\n",
+		printf(", interrupted after %u:%s, not running\n",
 		       hours, t);
 }
 
@@ -274,18 +294,18 @@ static void print_scrub_dev(struct btrfs_ioctl_dev_info_args *di,
 		if (raw)
 			print_scrub_full(p);
 		else
-			print_scrub_summary(p);
+			print_scrub_summary(p, ss, di->bytes_used);
 	}
 }
 
-static void print_fs_stat(struct scrub_fs_stat *fs_stat, int raw)
+static void print_fs_stat(struct scrub_fs_stat *fs_stat, int raw, u64 bytes_total)
 {
 	_print_scrub_ss(&fs_stat->s);
 
 	if (raw)
 		print_scrub_full(&fs_stat->p);
 	else
-		print_scrub_summary(&fs_stat->p);
+		print_scrub_summary(&fs_stat->p, &fs_stat->s, bytes_total);
 }
 
 static void free_history(struct scrub_file_record **last_scrubs)
@@ -1487,6 +1507,8 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv,
 
 	if (do_print) {
 		const char *append = "done";
+		u64 total_bytes_used = 0;
+
 		if (!do_stats_per_dev)
 			init_fs_stat(&fs_stat);
 		for (i = 0; i < fi_args.num_devices; ++i) {
@@ -1502,10 +1524,11 @@ static int scrub_start(const struct cmd_struct *cmd, int argc, char **argv,
 				add_to_fs_stat(&sp[i].scrub_args.progress,
 						&sp[i].stats, &fs_stat);
 			}
+			total_bytes_used += di_args[i].bytes_used;
 		}
 		if (!do_stats_per_dev) {
 			printf("scrub %s for %s\n", append, fsid);
-			print_fs_stat(&fs_stat, print_raw);
+			print_fs_stat(&fs_stat, print_raw, total_bytes_used);
 		}
 	}
 
@@ -1771,6 +1794,8 @@ static int cmd_scrub_status(const struct cmd_struct *cmd, int argc, char **argv)
 					&last_scrub->stats);
 		}
 	} else {
+		u64 total_bytes_used = 0;
+
 		init_fs_stat(&fs_stat);
 		fs_stat.s.in_progress = in_progress;
 		for (i = 0; i < fi_args.num_devices; ++i) {
@@ -1780,8 +1805,9 @@ static int cmd_scrub_status(const struct cmd_struct *cmd, int argc, char **argv)
 				continue;
 			add_to_fs_stat(&last_scrub->p, &last_scrub->stats,
 					&fs_stat);
+			total_bytes_used += di_args[i].bytes_used;
 		}
-		print_fs_stat(&fs_stat, print_raw);
+		print_fs_stat(&fs_stat, print_raw, total_bytes_used);
 	}
 
 out: