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From: Coly Li <colyli@suse.de>
To: linux-bcache@vger.kernel.org
Cc: linux-block@vger.kernel.org, hare@suse.de, Coly Li <colyli@suse.de>
Subject: [PATCH v4 07/16] bcache: struct cache_sb is only for in-memory super block now
Date: Fri, 17 Jul 2020 19:22:27 +0800	[thread overview]
Message-ID: <20200717112236.44761-8-colyli@suse.de> (raw)
In-Reply-To: <20200717112236.44761-1-colyli@suse.de>

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>
---
 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


  parent reply	other threads:[~2020-07-17 11:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17 11:22 [PATCH v4 00/16] bcache: extend bucket size to 32bit width Coly Li
2020-07-17 11:22 ` [PATCH v4 01/16] bcache: add read_super_common() to read major part of super block Coly Li
2020-07-17 11:22 ` [PATCH v4 02/16] bcache: add more accurate error information in read_super_common() Coly Li
2020-07-17 11:22 ` [PATCH v4 03/16] bcache: disassemble the big if() checks in bch_cache_set_alloc() Coly Li
2020-07-17 11:22 ` [PATCH v4 04/16] bcache: fix super block seq numbers comparision in register_cache_set() Coly Li
2020-07-17 11:22 ` [PATCH v4 05/16] bcache: increase super block version for cache device and backing device Coly Li
2020-07-17 11:22 ` [PATCH v4 06/16] bcache: move bucket related code into read_super_common() Coly Li
2020-07-17 11:22 ` Coly Li [this message]
2020-07-17 11:22 ` [PATCH v4 08/16] bcache: introduce meta_bucket_pages() related helper routines Coly Li
2020-07-17 11:22 ` [PATCH v4 09/16] bcache: handle c->uuids properly for bucket size > 8MB Coly Li
2020-07-17 11:22 ` [PATCH v4 10/16] bcache: handle cache prio_buckets and disk_buckets " Coly Li
2020-07-17 11:22 ` [PATCH v4 11/16] bcache: handle cache set verify_ondisk " Coly Li
2020-07-17 11:22 ` [PATCH v4 12/16] bcache: handle btree node memory allocation " Coly Li
2020-07-17 11:22 ` [PATCH v4 13/16] bcache: add bucket_size_hi into struct cache_sb_disk for large bucket Coly Li
2020-07-17 11:22 ` [PATCH v4 14/16] bcache: add sysfs file to display feature sets information of cache set Coly Li
2020-07-17 11:22 ` [PATCH v4 15/16] bcache: avoid extra memory allocation from mempool c->fill_iter Coly Li
2020-07-17 11:22 ` [PATCH v4 16/16] bcache: avoid extra memory consumption in struct bbio for large bucket size Coly Li

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