Re: [PATCH v2 12/14] replay-log: add support for replaying ops in target device sector range

[Eryu Guan <eguan@redhat.com>]

On Wed, Aug 30, 2017 at 05:51:44PM +0300, Amir Goldstein wrote:
> 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>
> ---
>  src/log-writes/log-writes.c | 33 +++++++++++++++++++++++++++++++--
>  src/log-writes/log-writes.h |  2 ++
>  src/log-writes/replay-log.c | 31 +++++++++++++++++++++++++++++++
>  3 files changed, 64 insertions(+), 2 deletions(-)
> 
> diff --git a/src/log-writes/log-writes.c b/src/log-writes/log-writes.c
> index ba66a5c..d832c2a 100644
> --- a/src/log-writes/log-writes.c
> +++ b/src/log-writes/log-writes.c
> @@ -119,6 +119,24 @@ int log_discard(struct log *log, struct log_write_entry *entry)
>  
>  /*
>   * @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)
> +{
> +	if (!entry->nr_sectors)
> +		return 0;
> +	if (entry->sector + entry->nr_sectors < log->start_sector ||
> +	    entry->sector > log->end_sector)

Seems values from entry can't be used directly, need le64_to_cpu first I
think.

> +		return 1;
> +	return 0;
> +}
> +
> +/*
> + * @log: the log we are replaying.
>   * @entry: where we put the entry.
>   * @read_data: read the entry data as well, entry must be log->sectorsize sized
>   * if this is set.
> @@ -137,6 +155,7 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
>  	char *buf;
>  	ssize_t ret;
>  	off_t offset;
> +	u64 skip = 0;

int skip? and log_should_skip returns int too.

Thanks,
Eryu

>  
>  	if (log->cur_entry >= log->nr_entries)
>  		return 1;
> @@ -158,9 +177,11 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
>  		}
>  	}
>  
> -	if (log_writes_verbose) {
> +	skip = log_should_skip(log, entry);
> +	if (log_writes_verbose > 1 || (log_writes_verbose && !skip)) {
>  		offset = lseek(log->logfd, 0, SEEK_CUR);
> -		printf("replaying %d@%llu: sector %llu, size %llu, flags %llu\n",
> +		printf("%s %d@%llu: sector %llu, size %llu, flags %llu\n",
> +		       skip ? "skipping" : "replaying",
>  		       (int)log->cur_entry - 1, offset / log->sectorsize,
>  		       (unsigned long long)le64_to_cpu(entry->sector),
>  		       (unsigned long long)size,
> @@ -173,6 +194,14 @@ 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) {
> +		if (lseek(log->logfd, size, SEEK_CUR) == (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);
> diff --git a/src/log-writes/log-writes.h b/src/log-writes/log-writes.h
> index 13f98ff..fc84acf 100644
> --- a/src/log-writes/log-writes.h
> +++ b/src/log-writes/log-writes.h
> @@ -53,6 +53,8 @@ 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;
> diff --git a/src/log-writes/replay-log.c b/src/log-writes/replay-log.c
> index 87c03a2..971974b 100644
> --- a/src/log-writes/replay-log.c
> +++ b/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);
>  }
>  
> @@ -120,6 +130,8 @@ 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;
> @@ -240,6 +252,22 @@ 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();
>  		}
> @@ -257,6 +285,9 @@ 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");
> -- 
> 2.7.4
>