Ensure we never overlap with existing blocks
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/io_u.c b/io_u.c
index bffacb4..f451d1a 100644
--- a/io_u.c
+++ b/io_u.c
@@ -54,11 +54,8 @@
* If we have a mixed random workload, we may
* encounter blocks we already did IO to.
*/
- if ((td->o.ddir_nr == 1) && !random_map_free(f, block)) {
- if (!blocks)
- blocks = 1;
+ if ((td->o.ddir_nr == 1) && !random_map_free(f, block))
break;
- }
idx = RAND_MAP_IDX(f, block);
bit = RAND_MAP_BIT(f, block);
@@ -69,10 +66,20 @@
if (this_blocks + bit > BLOCKS_PER_MAP)
this_blocks = BLOCKS_PER_MAP - bit;
- if (this_blocks == BLOCKS_PER_MAP)
- mask = -1U;
- else
- mask = ((1U << this_blocks) - 1) << bit;
+ do {
+ if (this_blocks == BLOCKS_PER_MAP)
+ mask = -1U;
+ else
+ mask = ((1U << this_blocks) - 1) << bit;
+
+ if (!(f->file_map[idx] & mask))
+ break;
+
+ this_blocks--;
+ } while (this_blocks);
+
+ if (!this_blocks)
+ break;
f->file_map[idx] |= mask;
nr_blocks -= this_blocks;