On Thu, Mar 28, 2019 at 7:36 AM Qu Wenruo <wqu@xxxxxxxx> wrote:
>
> For kernel operation we have METADATA/FUA/FLUSH flags as a beacon, but
> for user space write we don't have any useful flag unless the user space
> tool call fsync() to generate a FLUSH bio.
>
> This means for user space write, we don't really have an equivalent of
> --next-fua to find super block write.
>
> So this patch will add a new option, --next-write <sector> to
> replay/find next write to certain sector.
> And normally the <sector> should be super block sector number.
>
> With that, we can replay to super block write even it's user space
> triggering the write.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
This is useful, but it could be simpler and even more useful.
See suggestion below.
> ---
> src/log-writes/replay-log.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/src/log-writes/replay-log.c b/src/log-writes/replay-log.c
> index c16df40e5741..0d0ec49c8a00 100644
> --- a/src/log-writes/replay-log.c
> +++ b/src/log-writes/replay-log.c
> @@ -9,6 +9,7 @@
> enum option_indexes {
> NEXT_FLUSH,
> NEXT_FUA,
> + NEXT_WRITE,
> START_ENTRY,
> END_MARK,
> LOG,
> @@ -28,6 +29,7 @@ enum option_indexes {
> static struct option long_options[] = {
> {"next-flush", no_argument, NULL, 0},
> {"next-fua", no_argument, NULL, 0},
> + {"next-write", required_argument, NULL, 0},
Suggest no_argument like next-fua,next-flush and assign
a special flag or something to find WRITE entries
because start/end-sector already gives to the ability
to filter by single sector or range of sectors.
If fact I added these option to debug the exact case you are
describing.
> {"start-entry", required_argument, NULL, 0},
> {"end-mark", required_argument, NULL, 0},
> {"log", required_argument, NULL, 0},
> @@ -53,6 +55,8 @@ static void usage(void)
> fprintf(stderr, "\t--limit <number> - number of entries to replay\n");
> fprintf(stderr, "\t--next-flush - replay to/find the next flush\n");
> fprintf(stderr, "\t--next-fua - replay to/find the next fua\n");
> + fprintf(stderr, "\t--next-write <sector> - replay to/find the next "
> + "write to <sector>\n");
> fprintf(stderr, "\t--start-entry <entry> - start at the given "
> "entry #\n");
> fprintf(stderr, "\t--start-mark <mark> - mark to start from\n");
> @@ -139,6 +143,7 @@ int main(int argc, char **argv)
> char *logfile = NULL, *replayfile = NULL, *fsck_command = NULL;
> struct log_write_entry *entry;
> u64 stop_flags = 0;
> + u64 stop_sector = 0;
> u64 start_entry = 0;
> u64 start_sector = 0;
> u64 end_sector = -1ULL;
> @@ -173,6 +178,14 @@ int main(int argc, char **argv)
> case NEXT_FUA:
> stop_flags |= LOG_FUA_FLAG;
> break;
> + case NEXT_WRITE:
> + stop_sector = strtoull(optarg, &tmp, 0);
> + if (tmp && *tmp != '\0') {
> + fprintf(stderr, "Invalid sector number\n");
> + exit(1);
> + }
> + tmp = NULL;
> + break;
> case START_ENTRY:
> start_entry = strtoull(optarg, &tmp, 0);
> if (tmp && *tmp != '\0') {
> @@ -324,7 +337,8 @@ int main(int argc, char **argv)
> while ((ret = log_seek_next_entry(log, entry, 1)) == 0) {
> num_entries++;
> if ((run_limit && num_entries == run_limit) ||
> - should_stop(entry, stop_flags, end_mark)) {
> + should_stop(entry, stop_flags, end_mark) ||
> + (stop_sector && entry->sector == stop_sector)) {
You seem to have only implemented "find" mode and not "replay" mode
(the log_replay_next_entry() loop).
I suggest that you work log_should_skip() into both "find" and "replay"
loops. i.e. (!log_should_skip() && should_stop()).
Thanks,
Amir.
