Re: [PATCH] ext4: fix #11321: create /proc/ext4/*/stats et al more carefully

Andreas Dilger
2008-09-06T07:57:23Z

On Sep 06, 2008 01:06 +0400, Alexey Dobriyan wrote:
> [PATCH] ext4: fix #11321: create /proc/ext4/*/stats more carefully
>
> ext4 creates per-suberblock directory in /proc/ext4/ . Name used as
> basis is taken from bdevname, which, surprise, can contain slash.
>
> However, proc while allowing to use proc_create("a/b", parent) form of
> PDE creation, assumes that parent/a was already created.
>
> bdevname in question is 'cciss/c0d0p9', directory is not created and all
> this stuff goes directly into /proc (which is real bug).
>
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2792,6 +2792,15 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
> return -EINVAL;
> }
> bdevname(sb->s_bdev, devname);
> + {
> + char *p = devname;
> +
> + while (*p != '\0') {
> + if (*p == '/')
> + *p = '!';
> + p++;
> + }
> + }

Why not use strchr(), which is normally optimized assembly:

char *p = devname;
while ((p = strchr(p, '/'))
*p = '_';

Using '!' as the separator makes it harder to use from shells I suspect,
so I'd suggest '_' instead.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.