Hi.
CC'ing f494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 author.
Please keep me CC'ed in replies, I'm not subscribed.
Wandering aimlessly in dm-cache source as of current linus master
(3.13-rc2, dc1ccc48159d63eca5089e507c82c7d22ef60839), I noticed this:
dm-cache-metadata.c:
int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
Note second argument is new_cache_size. But caller is doing:
dm-cache-target.c:
static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
[...]
r = dm_cache_resize(cache->cmd, cache->cache_size);
[...]
cache->cache_size = new_size;
dm_cache_resize is called with cache->cache_size before it gets updated
to new_size, so it looks like a no-op.
Can someone confirm my reading ?
If confirmed, the effect is that a shrink (only ? I'm not familiar with
cache metadata) operation can result in metadata inconsistent with
cache device size.
See attachment for proposed (untested) fix.
It applies cleanly as of current device-mapper for-next branch.
Regards,
--
Vincent Pelletier
>From 99fe12976eae6abd67be0c39798c61ca9acd683d Mon Sep 17 00:00:00 2001
Message-Id: <99fe12976eae6abd67be0c39798c61ca9acd683d.1385805937.git.plr.vincent@xxxxxxxxx>
From: Vincent Pelletier <plr.vincent@xxxxxxxxx>
Date: Sat, 30 Nov 2013 11:05:12 +0100
Subject: dm cache: actually shrink cache to new size
Signed-off-by: Vincent Pelletier <plr.vincent@xxxxxxxxx>
---
drivers/md/dm-cache-target.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 9efcf10..1b1469e 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2755,7 +2755,7 @@ static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
{
int r;
- r = dm_cache_resize(cache->cmd, cache->cache_size);
+ r = dm_cache_resize(cache->cmd, new_size);
if (r) {
DMERR("could not resize cache metadata");
return r;
--
1.8.4.4
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
