Re: [PATCH 32/35] staging: lustre: mount: fix lmd_parse() to handle commas in expr_list

From: Greg Kroah-Hartman
Date: Mon Nov 14 2016 - 10:12:41 EST


On Thu, Nov 10, 2016 at 12:31:02PM -0500, James Simmons wrote:
> From: Jian Yu <jian.yu@xxxxxxxxx>
>
> The lmd_parse() function parses mount options with comma as
> delimiter without considering commas in expr_list as follows
> is a valid LNET nid range syntax:
>
> <expr_list> :== '[' <range_expr> [ ',' <range_expr>] ']'
>
> This patch fixes the above issue by using cfs_parse_nidlist()
> to parse nid range list instead of using class_parse_nid_quiet()
> to parse only one nid.

ugh, parsing mount strings in the kernel in odd ways, what could ever go
wrong...

>
> Signed-off-by: Jian Yu <jian.yu@xxxxxxxxx>
> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5690
> Reviewed-on: http://review.whamcloud.com/17036
> Reviewed-by: Niu Yawei <yawei.niu@xxxxxxxxx>
> Reviewed-by: Bob Glossman <bob.glossman@xxxxxxxxx>
> Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
> Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
> ---
> drivers/staging/lustre/lustre/obdclass/obd_mount.c | 91 ++++++++++++++++++--
> 1 files changed, 85 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/obdclass/obd_mount.c b/drivers/staging/lustre/lustre/obdclass/obd_mount.c
> index 2283e92..1eb8e71 100644
> --- a/drivers/staging/lustre/lustre/obdclass/obd_mount.c
> +++ b/drivers/staging/lustre/lustre/obdclass/obd_mount.c
> @@ -871,6 +871,87 @@ static int lmd_parse_mgs(struct lustre_mount_data *lmd, char **ptr)
> return 0;
> }
>
> +/**
> + * Find the first comma delimiter from the specified \a buf and make \a *endh
> + * point to the string starting with the comma. The commas in expression list
> + * [...] will be skipped.
> + *
> + * \param[in] buf a comma-separated string
> + * \param[in] endh a pointer to a pointer that will point to the string
> + * starting with the comma

Please drop this mess of \param, it's not needed and is not kernel-doc
format.

> + *
> + * \retval 0 if comma delimiter is found
> + * \retval 1 if comma delimiter is not found
> + */
> +static int lmd_find_comma(char *buf, char **endh)
> +{
> + char *c = buf;
> + int skip = 0;
> +
> + if (!buf)
> + return 1;
> +
> + while (*c != '\0') {
> + if (*c == '[')
> + skip++;
> + else if (*c == ']')
> + skip--;
> +
> + if (*c == ',' && !skip) {
> + if (endh)
> + *endh = c;
> + return 0;
> + }
> + c++;
> + }
> + return 1;
> +}

Don't we have a standard string search function for finding a string in
a string already in the kernel? Why write another one?

Or better yet, why are you using such a crazy string in the first place
from userspace?

Please fix this up and resend.

thanks,

greg k-h