We have struct cache_sb_disk for on-disk super block already, it is
unnecessary to keep the in-memory super block format exactly mapping
to the on-disk struct layout.
This patch adds code comments to notice that struct cache_sb is not
exactly mapping to cache_sb_disk, and removes the useless member csum
and pad[5].
Although struct cache_sb does not belong to uapi, but there are still
some on-disk format related macros reference it and it is unncessary to
get rid of such dependency now. So struct cache_sb will continue to stay
in include/uapi/linux/bache.h for now.
Signed-off-by: Coly Li <colyli@xxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
---
include/uapi/linux/bcache.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h
index 47df2db2e727..0ef984ea515a 100644
--- a/include/uapi/linux/bcache.h
+++ b/include/uapi/linux/bcache.h
@@ -215,8 +215,13 @@ struct cache_sb_disk {
__le64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
};
+/*
+ * This is for in-memory bcache super block.
+ * NOTE: cache_sb is NOT exactly mapping to cache_sb_disk, the member
+ * size, ordering and even whole struct size may be different
+ * from cache_sb_disk.
+ */
struct cache_sb {
- __u64 csum;
__u64 offset; /* sector where this sb was written */
__u64 version;
@@ -236,8 +241,6 @@ struct cache_sb {
__u64 feature_incompat;
__u64 feature_ro_compat;
- __u64 pad[5];
-
union {
struct {
/* Cache devices */
@@ -245,7 +248,6 @@ struct cache_sb {
__u16 block_size; /* sectors */
__u16 bucket_size; /* sectors */
-
__u16 nr_in_set;
__u16 nr_this_dev;
};
--
2.26.2
