[Sheepdog] [RFC PATCH] sheep: add nohalt to sheepdog_config

[Liu Yuan]

On 10/19/2011 02:25 PM, MORITA Kazutaka wrote:

> Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> ---
> Hi Yuan,
> 
> Isn't it better to add a nohalt field instead of a generic name
> "flags"?  This would be the most intuitive way.  The size of config
> file wouldn't become a problem, so we don't need to save bits, I
> think.
> 
> How do you think?
> 


Hi Kazum,

I think we'd better live with flags. with set/get_cluster_falgs(). Then
we can add more options (for e.g. noqlimit, no rquest queue limit later
for the cluster that doesn't need it at all. etc.), which will use this
interface to store it in the local storage.

If not, we'll have to write functions to store those options locally
every time we add a new option.

Thanks,
Yuan

> 
> 
>  sheep/sheep_priv.h |    2 ++
>  sheep/store.c      |   48 +++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 49 insertions(+), 1 deletions(-)
> 
> diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
> index cccb986..e087558 100644
> --- a/sheep/sheep_priv.h
> +++ b/sheep/sheep_priv.h
> @@ -210,6 +210,8 @@ int update_epoch_store(uint32_t epoch);
>  
>  int set_global_nr_copies(uint32_t copies);
>  int get_global_nr_copies(uint32_t *copies);
> +int set_cluster_nohalt(int on);
> +int is_cluster_nohalt(void);
>  
>  #define NR_GW_WORKER_THREAD 4
>  #define NR_IO_WORKER_THREAD 4
> diff --git a/sheep/store.c b/sheep/store.c
> index 3da5713..addc41a 100644
> --- a/sheep/store.c
> +++ b/sheep/store.c
> @@ -27,7 +27,7 @@
>  struct sheepdog_config {
>  	uint64_t ctime;
>  	uint32_t copies;
> -	uint32_t flags;
> +	uint32_t nohalt;
>  };
>  
>  static char *obj_path;
> @@ -2054,3 +2054,49 @@ int get_global_nr_copies(uint32_t *copies)
>  
>  	return SD_RES_SUCCESS;
>  }
> +
> +int set_cluster_nohalt(int on)
> +{
> +	int fd, ret;
> +	struct sheepdog_config config = {
> +		.nohalt = on,
> +	};
> +
> +	fd = open(config_path, O_SYNC | O_WRONLY);
> +	if (fd < 0)
> +		return SD_RES_EIO;
> +
> +	ret = jrnl_perform(fd, &config.nohalt, sizeof(config.nohalt),
> +			   offsetof(struct sheepdog_config, nohalt),
> +			   config_path, jrnl_path);
> +	close(fd);
> +
> +	if (ret != 0)
> +		return SD_RES_EIO;
> +
> +	return SD_RES_SUCCESS;
> +}
> +
> +/*
> + * Returns 1 if the cluster serves the IO requests even if there
> + * aren't enough redundant nodes.  Otherwise, returns 0.  On error,
> + * returns a negative value
> + */
> +int is_cluster_nohalt(void)
> +{
> +	int fd, ret;
> +	struct sheepdog_config config;
> +
> +	fd = open(config_path, O_RDONLY);
> +	if (fd < 0)
> +		return SD_RES_EIO;
> +
> +	ret = pread64(fd, &config.nohalt, sizeof(config.nohalt),
> +		      offsetof(struct sheepdog_config, nohalt));
> +	close(fd);
> +
> +	if (ret != sizeof(config.nohalt))
> +		return -SD_RES_EIO;
> +
> +	return !!config.nohalt;
> +}