On Tue, 21 Jan 2014 15:00:28 +0100, Andreas Rohner wrote:
> This adds struct nilfs_suinfo_update and some flags. It contains the
> information needed to update one entry of segment usage information in
> the SUFILE. The flags specify, which fields need to be updated.
>
> This can be used to update segment usage information from userspace with an
> ioctl.
>
> Signed-off-by: Andreas Rohner <[email protected]>
> ---
> include/linux/nilfs2_fs.h | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h
> index 9875576..2ee1594 100644
> --- a/include/linux/nilfs2_fs.h
> +++ b/include/linux/nilfs2_fs.h
> @@ -709,6 +709,45 @@ static inline int nilfs_suinfo_clean(const struct
> nilfs_suinfo *si)
> return !si->sui_flags;
> }
>
> +/**
> + * nilfs_suinfo_update - segment usage information update
> + * @sup_segnum: segment number
> + * @sup_flags: flags for which fields are active in sup_sui
> + * @sup_sui: segment usage information
> + */
> +struct nilfs_suinfo_update {
> + __u64 sup_segnum;
> + __u32 sup_flags;
> + struct nilfs_suinfo sup_sui;
> +};
This structure is not aligned on 8 byte boundary. You need a 4 byte
pad to make the alignment architecture independent since the structure
already has some 64-bit variables.
If you do not so, the ioctl will lose compatibility, for instance,
between 32 bit userland programs and 64 bit kernel.
struct nilfs_suinfo_update {
__u64 sup_segnum;
__u32 sup_flags;
__u32 sup_reserved;
struct nilfs_suinfo sup_sui;
};
Do you really need different suinfo update flags per segment ?
If it's not so, we don't have to add nilfs_suinfo_update structure.
v_flags of nilfs_argv structure looks to be available for that
purpose. It's just a confirmation. Basically, I think this extension
is acceptable.
Regards,
Ryusuke Konishi
> +
> +enum {
> + NILFS_SUINFO_UPDATE_LASTMOD,
> + NILFS_SUINFO_UPDATE_NBLOCKS,
> + NILFS_SUINFO_UPDATE_FLAGS,
> +};
> +
> +#define NILFS_SUINFO_UPDATE_FNS(flag, name) \
> +static inline void \
> +nilfs_suinfo_update_set_##name(struct nilfs_suinfo_update *sup)
> \
> +{ \
> + sup->sup_flags |= 1UL << NILFS_SUINFO_UPDATE_##flag; \
> +} \
> +static inline void \
> +nilfs_suinfo_update_clear_##name(struct nilfs_suinfo_update *sup) \
> +{ \
> + sup->sup_flags &= ~(1UL << NILFS_SUINFO_UPDATE_##flag); \
> +} \
> +static inline int \
> +nilfs_suinfo_update_##name(const struct nilfs_suinfo_update *sup) \
> +{ \
> + return !!(sup->sup_flags & (1UL << NILFS_SUINFO_UPDATE_##flag));\
> +}
> +
> +NILFS_SUINFO_UPDATE_FNS(LASTMOD, lastmod)
> +NILFS_SUINFO_UPDATE_FNS(NBLOCKS, nblocks)
> +NILFS_SUINFO_UPDATE_FNS(FLAGS, flags)
> +
> /* ioctl */
> enum {
> NILFS_CHECKPOINT,
> --
> 1.8.5.3
>
> --
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