On Wed, Feb 05 2014, Jens Axboe wrote:
> On Wed, Feb 05 2014, Grant Grundler wrote:
> > > It does - that's the log_io_piece() mechanism. The writer will generate
> > > on, and verify will read those and verify. We just have to ensure that
> > > it is correct in the way that it is logged. The alternative would be to
> > > rely purely on the generator rollback, and for that you would then need
> > > some specific notification on how far the reader could proceed, if async
> > > verify_backlog is used.
> >
> > Yes - I was referring to the "rely purely on generator rollback".
> >
> > Once log_io_piece() is called, the verify code assumes the IO is
> > complete...which isn't true if log_io_piece() is used to record "order
> > issued".
>
> Right, we'd need to ensure the state is accurately known to the
> verifier.
Something like this should work, though I don't like the extra
overhead... Totally untested.
diff --git a/backend.c b/backend.c
index 62fa17c3a209..9ececaa1d5af 100644
--- a/backend.c
+++ b/backend.c
@@ -731,8 +731,7 @@ static uint64_t do_io(struct thread_data *td)
if (td_write(td) && io_u->ddir == DDIR_WRITE &&
td->o.do_verify &&
td->o.verify != VERIFY_NONE &&
- !td->o.experimental_verify &&
- !(td->flags & TD_F_VER_BACKLOG))
+ !td->o.experimental_verify)
log_io_piece(td, io_u);
ret = td_io_queue(td, io_u);
diff --git a/io_u.c b/io_u.c
index 4264cd54115c..64ff73cd5555 100644
--- a/io_u.c
+++ b/io_u.c
@@ -1285,6 +1285,7 @@ again:
io_u->acct_ddir = -1;
td->cur_depth++;
io_u->flags |= IO_U_F_IN_CUR_DEPTH;
+ io_u->ipo = NULL;
} else if (td->o.verify_async) {
/*
* We ran out, wait for async verify threads to finish and
@@ -1568,6 +1569,15 @@ static void io_completed(struct thread_data *td, struct
io_u *io_u,
td_io_u_lock(td);
assert(io_u->flags & IO_U_F_FLIGHT);
io_u->flags &= ~(IO_U_F_FLIGHT | IO_U_F_BUSY_OK);
+
+ /*
+ * Mark IO ok to verify
+ */
+ if (io_u->ipo) {
+ io_u->ipo->flags &= ~IP_F_IN_FLIGHT;
+ write_barrier();
+ }
+
td_io_u_unlock(td);
if (ddir_sync(io_u->ddir)) {
@@ -1623,17 +1633,6 @@ static void io_completed(struct thread_data *td, struct
io_u *io_u,
utime_since_now(&td->start));
}
- /*
- * Verify_backlog enable: We need to log the write job after
- * finishing it to prevent verifying before finish writing.
- */
- if (td_write(td) && idx == DDIR_WRITE &&
- td->o.do_verify &&
- td->o.verify != VERIFY_NONE &&
- !td->o.experimental_verify &&
- (td->flags & TD_F_VER_BACKLOG))
- log_io_piece(td, io_u);
-
icd->bytes_done[idx] += bytes;
if (io_u->end_io) {
diff --git a/ioengine.h b/ioengine.h
index 0756bc7e6c13..37627bb1dc76 100644
--- a/ioengine.h
+++ b/ioengine.h
@@ -71,6 +71,8 @@ struct io_u {
*/
unsigned long buf_filled_len;
+ struct io_piece *ipo;
+
union {
#ifdef CONFIG_LIBAIO
struct iocb iocb;
diff --git a/iolog.c b/iolog.c
index 017b235c217a..5fd9416c036e 100644
--- a/iolog.c
+++ b/iolog.c
@@ -189,6 +189,9 @@ void log_io_piece(struct thread_data *td, struct io_u *io_u)
ipo->offset = io_u->offset;
ipo->len = io_u->buflen;
ipo->numberio = io_u->numberio;
+ ipo->flags = IP_F_IN_FLIGHT;
+
+ io_u->ipo = ipo;
if (io_u_should_trim(td, io_u)) {
flist_add_tail(&ipo->trim_list, &td->trim_list);
diff --git a/iolog.h b/iolog.h
index 321576dbe611..3ec48f2100fe 100644
--- a/iolog.h
+++ b/iolog.h
@@ -67,6 +67,7 @@ enum {
IP_F_ONRB = 1,
IP_F_ONLIST = 2,
IP_F_TRIMMED = 4,
+ IP_F_IN_FLIGHT = 8,
};
/*
diff --git a/verify.c b/verify.c
index 90cd093add1f..93731228f1b6 100644
--- a/verify.c
+++ b/verify.c
@@ -1022,11 +1022,27 @@ int get_next_verify(struct thread_data *td, struct io_u
*io_u)
struct rb_node *n = rb_first(&td->io_hist_tree);
ipo = rb_entry(n, struct io_piece, rb_node);
+
+ /*
+ * Ensure that the associated IO has completed
+ */
+ read_barrier();
+ if (ipo->flags & IP_F_IN_FLIGHT)
+ goto nothing;
+
rb_erase(n, &td->io_hist_tree);
assert(ipo->flags & IP_F_ONRB);
ipo->flags &= ~IP_F_ONRB;
} else if (!flist_empty(&td->io_hist_list)) {
ipo = flist_entry(td->io_hist_list.next, struct io_piece, list);
+
+ /*
+ * Ensure that the associated IO has completed
+ */
+ read_barrier();
+ if (ipo->flags & IP_F_IN_FLIGHT)
+ goto nothing;
+
flist_del(&ipo->list);
assert(ipo->flags & IP_F_ONLIST);
ipo->flags &= ~IP_F_ONLIST;
@@ -1072,6 +1088,7 @@ int get_next_verify(struct thread_data *td, struct io_u
*io_u)
return 0;
}
+nothing:
dprint(FD_VERIFY, "get_next_verify: empty\n");
return 1;
}
--
Jens Axboe
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