Re: [PATCH v2 06/17] bcache: increase super block version for cache device and backing device

Hannes Reinecke
2020-07-15T06:11:38Z

On 7/15/20 7:46 AM, Coly Li wrote:
> The new added super block version BCACHE_SB_VERSION_BDEV_WITH_FEATURES
> (5) BCACHE_SB_VERSION_CDEV_WITH_FEATURES value (6), is for the feature
> set bits.
>
> Devices have super block version equal to the new version will have
> three new members for feature set bits in the on-disk super block,
> /*078*/ __le64 feature_compat;
> /*080*/ __le64 feature_incompat;
> /*088*/ __le64 feature_ro_compat;
>
> They are used for further new features which may introduce on-disk
> format change, and avoid unncessary super block version increase.
>
> The very basic features handling code skeleton is also initialized in
> this patch.
>
> Signed-off-by: Coly Li <colyli@suse.de>
> ---
> drivers/md/bcache/features.h | 78 ++++++++++++++++++++++++++++++++++++
> drivers/md/bcache/super.c | 32 +++++++++++++--
> include/uapi/linux/bcache.h | 29 ++++++++++----
> 3 files changed, 128 insertions(+), 11 deletions(-)
> create mode 100644 drivers/md/bcache/features.h
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
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