From: Hannes Reinecke <hare@suse.de>
To: Coly Li <colyli@suse.de>, linux-bcache@vger.kernel.org
Cc: linux-block@vger.kernel.org
Subject: Re: [PATCH v2 08/17] bcache: struct cache_sb is only for in-memory super block now
Date: Wed, 15 Jul 2020 08:45:33 +0200 [thread overview]
Message-ID: <18bb79b5-8a09-483e-b794-ec73bca5c943@suse.de> (raw)
In-Reply-To: <20200715054612.6349-9-colyli@suse.de>
On 7/15/20 7:46 AM, Coly Li wrote:
> 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 anymore, and removes the useless member
> csum and pad[5].
>
> Although struct cache_sb does not belong to uapi anymore, 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>
> ---
> 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 3c0aebb4a878..f5106c5939b0 100644
> --- a/include/uapi/linux/bcache.h
> +++ b/include/uapi/linux/bcache.h
> @@ -216,8 +216,13 @@ struct cache_sb_disk {
> /*8d0*/
> };
>
> +/*
> + * This is for in-memory bcache super block.
> + * NOTE: cache_sb is NOT exactly mapping to cache_sb_disk anymore,
> + * the member size, ordering and even whole struct size may be
> + * different from cache_sb_disk now.
> + */
> struct cache_sb {
> - __u64 csum;
> __u64 offset; /* sector where this sb was written */
> __u64 version;
>
> @@ -237,8 +242,6 @@ struct cache_sb {
> __u64 feature_incompat;
> __u64 feature_ro_compat;
>
> - __u64 pad[5];
> -
> union {
> struct {
> /* Cache devices */
> @@ -246,7 +249,6 @@ struct cache_sb {
>
> __u16 block_size; /* sectors */
> __u16 bucket_size; /* sectors */
> -
> __u16 nr_in_set;
> __u16 nr_this_dev;
> };
>
I would drop the 'anymore' from the description, as this implies it
changed recently. But otherwise:
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer
next prev parent reply other threads:[~2020-07-15 6:45 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 5:45 [PATCH v2 00/17] bcache: extend bucket size to 32bit width Coly Li
2020-07-15 5:45 ` [PATCH v2 01/17] bcache: add comments to mark member offset of struct cache_sb_disk Coly Li
2020-07-15 6:02 ` Hannes Reinecke
2020-07-15 9:03 ` Coly Li
2020-07-15 9:08 ` Johannes Thumshirn
2020-07-15 10:35 ` Coly Li
2020-07-15 5:45 ` [PATCH v2 02/17] bcache: add read_super_basic() to read major part of super block Coly Li
2020-07-15 6:03 ` Hannes Reinecke
2020-07-15 5:45 ` [PATCH v2 03/17] bcache: add more accurate error information in read_super_basic() Coly Li
2020-07-15 6:04 ` Hannes Reinecke
2020-07-15 5:45 ` [PATCH v2 04/17] bcache: disassemble the big if() checks in bch_cache_set_alloc() Coly Li
2020-07-15 6:08 ` Hannes Reinecke
2020-07-15 5:46 ` [PATCH v2 05/17] bcache: fix super block seq numbers comparision in register_cache_set() Coly Li
2020-07-15 6:10 ` Hannes Reinecke
2020-07-15 5:46 ` [PATCH v2 06/17] bcache: increase super block version for cache device and backing device Coly Li
2020-07-15 6:11 ` Hannes Reinecke
2020-07-15 5:46 ` [PATCH v2 07/17] bcache: move bucket related code into read_super_basic() Coly Li
2020-07-15 6:44 ` Hannes Reinecke
2020-07-15 5:46 ` [PATCH v2 08/17] bcache: struct cache_sb is only for in-memory super block now Coly Li
2020-07-15 6:45 ` Hannes Reinecke [this message]
2020-07-15 5:46 ` [PATCH v2 09/17] bcache: introduce meta_bucket_pages() related helper routines Coly Li
2020-07-15 5:46 ` [PATCH v2 10/17] bcache: handle c->uuids properly for bucket size > 8MB Coly Li
2020-07-15 5:46 ` [PATCH v2 11/17] bcache: handle cache prio_buckets and disk_buckets " Coly Li
2020-07-15 5:46 ` [PATCH v2 12/17] bcache: handle cache set verify_ondisk " Coly Li
2020-07-15 5:46 ` [PATCH v2 13/17] bcache: handle btree node memory allocation " Coly Li
2020-07-15 5:46 ` [PATCH v2 14/17] bcache: add bucket_size_hi into struct cache_sb_disk for large bucket Coly Li
2020-07-15 5:46 ` [PATCH v2 15/17] bcache: add sysfs file to display feature sets information of cache set Coly Li
2020-07-15 5:46 ` [PATCH v2 16/17] bcache: avoid extra memory allocation from mempool c->fill_iter Coly Li
2020-07-15 5:46 ` [PATCH v2 17/17] bcache: avoid extra memory consumption in struct bbio for large bucket size Coly Li
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