From: Jens Axboe <axboe@fb.com>
Date: Thu, 5 Jan 2017 17:26:08 +0000 (-0700)
Subject: verify: ensure that verify_interval is always a factor of min/max bs
X-Git-Tag: fio-2.17~23
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=9258468e828cfe1c31b977635994003fe388398e

verify: ensure that verify_interval is always a factor of min/max bs

A previous commit force aligned the buffer length to the
verify_interval, but that breaks if max_bs isn't a multiple
of min_bs. If that isn't the case, we can align the block size
bigger than the IO unit really is. This causes corruption and
failures.

Fixes: a9f70b1f5087 ("Make sure io_u->buflen is aligned to the verify_interval")
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/init.c b/init.c
index c9bf78f6..1ba8fe6e 100644
--- a/init.c
+++ b/init.c
@@ -564,6 +564,24 @@ static unsigned long long get_rand_start_delay(struct thread_data *td)
 	return delayrange;
 }
 
+static unsigned int gcd(unsigned int m, unsigned int n)
+{
+	unsigned int r;
+
+	if (!m || !n)
+		return 0;
+
+	do {
+		r = m % n;
+		if (!r)
+			break;
+		m = n;
+		n = r;
+	} while (1);
+
+	return n;
+}
+
 /*
  * Lazy way of fixing up options that depend on each other. We could also
  * define option callback handlers, but this is easier.
@@ -739,6 +757,15 @@ static int fixup_options(struct thread_data *td)
 			o->verify_interval = o->min_bs[DDIR_WRITE];
 		else if (td_read(td) && o->verify_interval > o->min_bs[DDIR_READ])
 			o->verify_interval = o->min_bs[DDIR_READ];
+
+		/*
+		 * Verify interval must be a factor or both min and max
+		 * write size
+		 */
+		if (o->verify_interval % o->min_bs[DDIR_WRITE] ||
+		    o->verify_interval % o->max_bs[DDIR_WRITE])
+			o->verify_interval = gcd(o->min_bs[DDIR_WRITE],
+							o->max_bs[DDIR_WRITE]);
 	}
 
 	if (o->pre_read) {
diff --git a/io_u.c b/io_u.c
index 74206297..1daaf7be 100644
--- a/io_u.c
+++ b/io_u.c
@@ -576,10 +576,6 @@ static unsigned int __get_next_buflen(struct thread_data *td, struct io_u *io_u,
 			}
 		}
 
-		if (td->o.verify != VERIFY_NONE)
-			buflen = (buflen + td->o.verify_interval - 1) &
-				~(td->o.verify_interval - 1);
-
 		if (!td->o.bs_unaligned && is_power_of_2(minbs))
 			buflen &= ~(minbs - 1);