replay-log: add support for replaying ops in target device sector range

Using command line options --start-sector and --end-sector, only
operations acting on the specified target device range will be
replayed.

Single vebbose mode (-v) prints out only replayed operations.
Double verbose mode (-vv) prints out also skipped operations.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

src/log-writes/log-writes.c

@@ -117,6 +117,27 @@ int log_discard(struct log *log, struct log_write_entry *entry)
 	return 0;
 }
 
+/*
+ * @log: the log we are replaying.
+ * @entry: entry to be replayed.
+ *
+ * @return: 0 if we should replay the entry, > 0 if we should skip it.
+ *
+ * Should we skip the entry in our log or replay onto the replay device.
+ */
+int log_should_skip(struct log *log, struct log_write_entry *entry)
+{
+	u64 sector = le64_to_cpu(entry->sector);
+	u64 nr_sectors = le64_to_cpu(entry->nr_sectors);
+
+	if (!nr_sectors)
+		return 0;
+	if (sector + nr_sectors <= log->start_sector ||
+	    sector > log->end_sector)
+		return 1;
+	return 0;
+}
+
 /*
  * @entry: entry to be replayed.
  *
@@ -157,6 +178,7 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
 	char *buf;
 	ssize_t ret;
 	off_t offset;
+	int skip = 0;
 
 	if (log->cur_entry >= log->nr_entries)
 		return 1;
@@ -185,8 +207,10 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
 		log->cur_pos += read_size;
 	}
 
-	if (log_writes_verbose) {
-		printf("replaying %d@%llu: sector %llu, size %llu, flags %llu\n",
+	skip = log_should_skip(log, entry);
+	if (log_writes_verbose > 1 || (log_writes_verbose && !skip)) {
+		printf("%s %d@%llu: sector %llu, size %llu, flags %llu\n",
+		       skip ? "skipping" : "replaying",
 		       (int)log->cur_entry - 1, log->cur_pos / log->sectorsize,
 		       (unsigned long long)le64_to_cpu(entry->sector),
 		       (unsigned long long)size,
@@ -199,6 +223,15 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
 	if (flags & LOG_DISCARD_FLAG)
 		return log_discard(log, entry);
 
+	if (skip) {
+		log->cur_pos = lseek(log->logfd, size, SEEK_CUR);
+		if (log->cur_pos == (off_t)-1) {
+			fprintf(stderr, "Error seeking in log: %d\n", errno);
+			return -1;
+		}
+		return 0;
+	}
+
 	buf = malloc(size);
 	if (!buf) {
 		fprintf(stderr, "Error allocating buffer %llu entry %llu\n", (unsigned long long)size, (unsigned long long)log->cur_entry - 1);

src/log-writes/log-writes.h

@@ -67,6 +67,8 @@ struct log {
 	int replayfd;
 	unsigned long flags;
 	u64 sectorsize;
+	u64 start_sector;
+	u64 end_sector;
 	u64 nr_entries;
 	u64 cur_entry;
 	u64 max_zero_size;

src/log-writes/replay-log.c

@@ -20,6 +20,8 @@ enum option_indexes {
 	FSCK,
 	CHECK,
 	START_MARK,
+	START_SECTOR,
+	END_SECTOR,
 };
 
 static struct option long_options[] = {
@@ -37,6 +39,8 @@ static struct option long_options[] = {
 	{"fsck", required_argument, NULL, 0},
 	{"check", required_argument, NULL, 0},
 	{"start-mark", required_argument, NULL, 0},
+	{"start-sector", required_argument, NULL, 0},
+	{"end-sector", required_argument, NULL, 0},
 	{ NULL, 0, NULL, 0 },
 };
 
@@ -61,6 +65,12 @@ static void usage(void)
 		"--check\n");
 	fprintf(stderr, "\t--check [<number>|flush|fua] when to check the "
 		"file system, mush specify --fsck\n");
+	fprintf(stderr, "\t--start-sector <sector> - replay ops on region "
+		"from <sector> onto <device>\n");
+	fprintf(stderr, "\t--end-sector <sector> - replay ops on region "
+		"to <sector> onto <device>\n");
+	fprintf(stderr, "\t-v or --verbose - print replayed ops\n");
+	fprintf(stderr, "\t-vv - print also skipped ops\n");
 	exit(1);
 }
 
@@ -129,6 +139,8 @@ int main(int argc, char **argv)
 	struct log_write_entry *entry;
 	u64 stop_flags = 0;
 	u64 start_entry = 0;
+	u64 start_sector = 0;
+	u64 end_sector = -1ULL;
 	u64 run_limit = 0;
 	u64 num_entries = 0;
 	u64 check_number = 0;
@@ -249,6 +261,22 @@ int main(int argc, char **argv)
 				tmp = NULL;
 			}
 			break;
+		case START_SECTOR:
+			start_sector = strtoull(optarg, &tmp, 0);
+			if (tmp && *tmp != '\0') {
+				fprintf(stderr, "Invalid sector number\n");
+				exit(1);
+			}
+			tmp = NULL;
+			break;
+		case END_SECTOR:
+			end_sector = strtoull(optarg, &tmp, 0);
+			if (tmp && *tmp != '\0') {
+				fprintf(stderr, "Invalid sector number\n");
+				exit(1);
+			}
+			tmp = NULL;
+			break;
 		default:
 			usage();
 		}
@@ -266,6 +294,9 @@ int main(int argc, char **argv)
 	if (!discard)
 		log->flags |= LOG_IGNORE_DISCARD;
 
+	log->start_sector = start_sector;
+	log->end_sector = end_sector;
+
 	entry = malloc(log->sectorsize);
 	if (!entry) {
 		fprintf(stderr, "Couldn't allocate buffer\n");