From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 1 Jul 2021 19:27:39 +0000 (-0600)
Subject: Merge branch 'dedupe_bugfix' of https://github.com/bardavid/fio
X-Git-Tag: fio-3.28~45
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=77c72e0f504364adf6a0e8f1155fdf3fd68ef248;hp=ea51055cbb2fcbca3935e25c78e8b6d358ca2b3f

Merge branch 'dedupe_bugfix' of https://github.com/bardavid/fio

* 'dedupe_bugfix' of https://github.com/bardavid/fio:
  dedupe: fixing bug with subsequent dedupe buffer generation
---

diff --git a/fio.h b/fio.h
index b05cb3df..83334652 100644
--- a/fio.h
+++ b/fio.h
@@ -259,6 +259,7 @@ struct thread_data {
 
 	struct frand_state buf_state;
 	struct frand_state buf_state_prev;
+	struct frand_state buf_state_ret;
 	struct frand_state dedupe_state;
 	struct frand_state zone_state;
 	struct frand_state prio_state;
diff --git a/io_u.c b/io_u.c
index b421a579..b60488a3 100644
--- a/io_u.c
+++ b/io_u.c
@@ -2182,8 +2182,16 @@ static struct frand_state *get_buf_state(struct thread_data *td)
 
 	v = rand_between(&td->dedupe_state, 1, 100);
 
-	if (v <= td->o.dedupe_percentage)
-		return &td->buf_state_prev;
+	if (v <= td->o.dedupe_percentage) {
+		/*
+		 * The caller advances the returned frand_state.
+		 * A copy of prev should be returned instead since
+		 * a subsequent intention to generate a deduped buffer
+		 * might result in generating a unique one
+		 */
+		frand_copy(&td->buf_state_ret, &td->buf_state_prev);
+		return &td->buf_state_ret;
+	}
 
 	return &td->buf_state;
 }