Re: [PATCH V5] xfs: cleanup the mount options

Dave Chinner
2012-07-23T23:34:10Z

On Wed, Jul 11, 2012 at 02:29:05PM +0800, Wanlong Gao wrote:
> - return simple_strtoul((const char *)s, endp, base) << shift_left_factor;
> + string = match_strdup(s);

GFP_KERNEL allocation....

> + if (!string)
> + return ENOMEM;
> +
> + *result = simple_strtoul((const char *)string, NULL, 0) <<
> + shift_left_factor;
> +
> + kfree(string);
> + return 0;
> +}
> +
> +STATIC int
> +match_name_strdup(substring_t *s, char *name)
> +{
> + char *string;
> + string = match_strdup(s);

GFP_KERNEL allocation....

> + if (!string)
> + return ENOMEM;
> +
> + name = kstrndup(string, MAXNAMELEN, GFP_KERNEL);

GFP_KERNEL allocation....

> + if (!name)
> + goto free;
> + return 0;

Leaks string - it should always be freed.

> +free:
> + kfree(string);
> + return ENOMEM;
> }
>
> /*
> @@ -166,11 +246,15 @@ xfs_parseargs(
> char *options)
> {
> struct super_block *sb = mp->m_super;
> - char *this_char, *value, *eov;
> + char *p;
> int dsunit = 0;
> int dswidth = 0;
> - int iosize = 0;
> __uint8_t iosizelog = 0;
> + int intarg;
> + unsigned long ularg;
> + substring_t args[MAX_OPT_ARGS];
> + char *orig = NULL;
> + int ret = 0;
>
> /*
> * set up the mount name first so all the errors will refer to the
> @@ -208,175 +292,192 @@ xfs_parseargs(
> if (!options)
> goto done;
>
> - while ((this_char = strsep(&options, ",")) != NULL) {
> - if (!*this_char)
> + options = kstrdup(options, GFP_NOFS);

GFP_NOFS allocation. Why is this GFP_NOFS, and all the other
allocations GFP_KERNEL? If it is not safe to use GFP_KERNEL
allocations here, then all of the above allocations need to be
GFP_NOFS, too.

> + if (!options) {
> + ret = ENOMEM;
> + goto done;
> + }
> +
> + orig = options;

Also, no need to set up orig like this. Just a simple:

orig = kstrdup(options, GFP_NOFS);
if (!orig) {
ret = ENOMEM;
goto done;
}

will work fine.

....

> if (mp->m_logbufs > 0)
> - seq_printf(m, "," MNTOPT_LOGBUFS "=%d", mp->m_logbufs);
> + seq_printf(seq, "," MNTOPT_LOGBUFS "=%d", mp->m_logbufs);
> if (mp->m_logbsize > 0)
> - seq_printf(m, "," MNTOPT_LOGBSIZE "=%dk", mp->m_logbsize >> 10);
> + seq_printf(seq, "," MNTOPT_LOGBSIZE "=%dk",
> + mp->m_logbsize >> 10);

Change of user visible output format here. That will break any
scripts that are parsing the output and expecting numbers. Just
leave it as a raw number.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com