Commit 4c1ccd08 authored Jul 25, 2020 by Coly Li Committed by Jens Axboe Jul 25, 2020

bcache: struct cache_sb is only for in-memory super block now



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@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 198efa35

include/uapi/linux/bcache.h

+6 −4

Original line number	Diff line number	Diff line
		@@ -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;
		};

Admin message