block: discard granularity might not be power of 2
In MD raid case, discard granularity might not be power of 2, for example, a
4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for
such cases.
Reported-by: Neil Brown <neilb@suse.de>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 779bb76..c50ecf0 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -611,7 +611,7 @@
bottom = b->discard_granularity + alignment;
/* Verify that top and bottom intervals line up */
- if (max(top, bottom) & (min(top, bottom) - 1))
+ if ((max(top, bottom) % min(top, bottom)) != 0)
t->discard_misaligned = 1;
}
@@ -619,8 +619,8 @@
b->max_discard_sectors);
t->discard_granularity = max(t->discard_granularity,
b->discard_granularity);
- t->discard_alignment = lcm(t->discard_alignment, alignment) &
- (t->discard_granularity - 1);
+ t->discard_alignment = lcm(t->discard_alignment, alignment) %
+ t->discard_granularity;
}
return ret;