[CRIU] [RFC PATCH 1/6] reserve the extra room in fstypes[]

[Pavel Emelyanov]

On 03/27/2015 08:55 PM, Oleg Nesterov wrote:
> Preparation. Enlarge fstypes[] to make it possible to add the new
> fstype's dynamically.
> 
> This means ths find_fstype_by_name() and decode_fstype() need the
> additional ->name == NULL check to terminate the search.
> 
> Also change them to start with "i == 1", we rely on the fact that
> fstypes[0] is FSTYPE__UNSUPPORTED anyway.
> 
> Signed-off-by: Oleg Nesterov <oleg at redhat.com>
> ---
>  mount.c |   26 +++++++++++++++++++-------
>  1 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/mount.c b/mount.c
> index 021c6e3..ff2bce5 100644
> --- a/mount.c
> +++ b/mount.c
> @@ -1033,7 +1033,7 @@ out:
>  	return ret;
>  }
>  
> -static struct fstype fstypes[] = {
> +static struct fstype fstypes[32] = {

This means that we can only add "32 - current_amount" of FSs run time.
This is not bad at the moment, but once we add more in this list we
will likely forget to extend this :)

Can we better make this thing dynamically allocated?

>  	{
>  		.name = "unsupported",
>  		.code = FSTYPE__UNSUPPORTED,
> @@ -1107,9 +1107,15 @@ struct fstype *find_fstype_by_name(char *fst)
>  	 * names anyway)
>  	 */
>  
> -	for (i = 0; i < ARRAY_SIZE(fstypes); i++)
> -		if (!strcmp(fstypes[i].name, fst))
> -			return fstypes + i;
> +	for (i = 1; i < ARRAY_SIZE(fstypes); i++) {
> +		struct fstype *fstype = fstypes + i;
> +
> +		if (!fstype->name)
> +			break;
> +
> +		if (!strcmp(fstype->name, fst))
> +			return fstype;
> +	}
>  
>  	return &fstypes[0];
>  }
> @@ -1121,9 +1127,15 @@ static struct fstype *decode_fstype(u32 fst)
>  	if (fst == FSTYPE__UNSUPPORTED)
>  		goto uns;
>  
> -	for (i = 0; i < ARRAY_SIZE(fstypes); i++)
> -		if (fstypes[i].code == fst)
> -			return fstypes + i;
> +	for (i = 1; i < ARRAY_SIZE(fstypes); i++) {
> +		struct fstype *fstype = fstypes + i;
> +
> +		if (!fstype->name)
> +			break;
> +
> +		if (fstype->code == fst)
> +			return fstype;
> +	}
>  uns:
>  	return &fstypes[0];
>  }
>