From 84422acde41c9cf462245de115d425cf5a82124c Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Tue, 19 Feb 2008 20:10:26 +0100
Subject: [PATCH] More random fixes

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 fio.h  |  3 ++-
 init.c |  1 +
 io_u.c | 21 +++++++++++++--------
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/fio.h b/fio.h
index d8c65950..7551ef60 100644
--- a/fio.h
+++ b/fio.h
@@ -683,7 +683,7 @@ static inline void fio_ro_check(struct thread_data *td, struct io_u *io_u)
 }
 
 #define BLOCKS_PER_MAP		(8 * sizeof(long))
-#define TO_MAP_BLOCK(td, f, b)	((b) / ((unsigned long long) (td)->o.rw_min_bs))
+#define TO_MAP_BLOCK(td, f, b)	(b)
 #define RAND_MAP_IDX(td, f, b)	(TO_MAP_BLOCK(td, f, b) / BLOCKS_PER_MAP)
 #define RAND_MAP_BIT(td, f, b)	(TO_MAP_BLOCK(td, f, b) & (BLOCKS_PER_MAP - 1))
 
@@ -981,6 +981,7 @@ enum {
 	FD_MEM,
 	FD_BLKTRACE,
 	FD_VERIFY,
+	FD_RANDOM,
 	FD_DEBUG_MAX,
 };
 
diff --git a/init.c b/init.c
index d559a7ac..92c5b8cd 100644
--- a/init.c
+++ b/init.c
@@ -811,6 +811,7 @@ struct debug_level debug_levels[] = {
 	{ .name = "mem",	.shift = FD_MEM, },
 	{ .name = "blktrace",	.shift = FD_BLKTRACE },
 	{ .name = "verify",	.shift = FD_VERIFY },
+	{ .name = "random",	.shift = FD_RANDOM },
 	{ },
 };
 
diff --git a/io_u.c b/io_u.c
index 9ab33f39..7ac31a0d 100644
--- a/io_u.c
+++ b/io_u.c
@@ -25,11 +25,13 @@ struct io_completion_data {
  * to yet. Used to make sure we cover the entire range in a fair fashion.
  */
 static int random_map_free(struct thread_data *td, struct fio_file *f,
-			   unsigned long long block)
+			   const unsigned long long block)
 {
 	unsigned int idx = RAND_MAP_IDX(td, f, block);
 	unsigned int bit = RAND_MAP_BIT(td, f, block);
 
+	dprint(FD_RANDOM, "free: b=%llu, idx=%u, bit=%u\n", block, idx, bit);
+
 	return (f->file_map[idx] & (1UL << bit)) == 0;
 }
 
@@ -78,7 +80,7 @@ static inline unsigned long long last_block(struct thread_data *td,
 {
 	unsigned long long max_blocks;
 
-	max_blocks = f->io_size / td->o.min_bs[ddir];
+	max_blocks = f->io_size / (unsigned long long) td->o.min_bs[ddir];
 	if (!max_blocks)
 		return 0;
 
@@ -91,11 +93,12 @@ static inline unsigned long long last_block(struct thread_data *td,
 static int get_next_free_block(struct thread_data *td, struct fio_file *f,
 			       enum fio_ddir ddir, unsigned long long *b)
 {
+	unsigned long long min_bs = td->o.rw_min_bs;
 	int i;
 
 	i = f->last_free_lookup;
 	*b = (i * BLOCKS_PER_MAP);
-	while ((*b) * td->o.rw_min_bs < f->real_file_size) {
+	while ((*b) * min_bs < f->real_file_size) {
 		if (f->file_map[i] != -1UL) {
 			*b += fio_ffz(f->file_map[i]);
 			if (*b > last_block(td, f, ddir))
@@ -115,12 +118,13 @@ static int get_next_free_block(struct thread_data *td, struct fio_file *f,
 static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
 				enum fio_ddir ddir, unsigned long long *b)
 {
-	unsigned long long r, rb;
+	unsigned long long r;
 	int loops = 5;
 
 	do {
 		r = os_random_long(&td->random_state);
-		*b = last_block(td, f, ddir);
+		dprint(FD_RANDOM, "off rand %llu\n", r);
+		*b = (last_block(td, f, ddir) - 1) * (r / ((unsigned long long) RAND_MAX + 1.0));
 
 		/*
 		 * if we are not maintaining a random map, we are done.
@@ -129,12 +133,13 @@ static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
 			return 0;
 
 		/*
-		 * calculate map offset and chec if it's free
+		 * calculate map offset and check if it's free
 		 */
-		rb = *b;
-		if (random_map_free(td, f, rb))
+		if (random_map_free(td, f, *b))
 			return 0;
 
+		dprint(FD_RANDOM, "get_next_rand_offset: offset %llu busy\n",
+									*b);
 	} while (--loops);
 
 	/*
-- 
2.25.1