Re: [patch 4/4] reiser4: reduce frame size of reiser4_init_super_data

[Laurent Riffard <laurent.riffard@free.fr>]

Oops, sorry, Edward already sent a patch for this...

~~
laurent


Le 07/10/2009 21:45, Laurent Riffard a écrit :
> Hi Edward,
> 
> This patch is buggy, isn't it ?
> 
> I've got 2 reiser4 FS in my /etc/fstab:
> 
> /dev/vglinux1/lvkernel-r4 /home/laurent/kernel reiser4 defaults,noatime,nodiratime,tmgr.atom_max_size=2048 0 0
> /dev/disk/by-uuid/b8dbe880-b664-49aa-8050-bddc91fd5e49 /mnt/diske reiser4 noauto,users,noatime,nodiratime 0 0
> 
> The first FS can't be mounted:
> 
> [  235.078342] reiser4[mount(4205)]: parse_options (fs/reiser4/init_super.c:253)[nikita-2307]:
> [  235.078345] WARNING: Unrecognized option: "tmgr.atom_max_size=2048"
> 
> although the second one can be mounted:
> 
> [ 3152.046324] reiser4: sda7: found disk format 4.0.0.
> 
> 
> Let's have a look at the code in fs/reiser4/init_super.c:
> 
> 
> 392 int reiser4_init_super_data(struct super_block *super, char *opt_string)
> 393 {
> 394         int result;
> 395         struct opt_desc *opts, *p;
> 396         reiser4_super_info_data *sbinfo = get_super_private(super);
> 397 
> ...
> 442         p = opts;
> 443 
> 444         push_sb_field_opts(p, opts, sbinfo);
> 
> p is passed by value to push_sb_field(). push_sb_field() does increment 
> its local copy of p, but here p remains equal to opts.
> 
> ...
> 501         result = parse_options(opt_string, opts, p - opts);
> 
> 3rd argument is 0 because p==opts. Now let's have a look at parse_options()
> 
> 230 static int parse_options(char *opt_string, struct opt_desc *opts, int nr_opts)
> 231 {
> 
> nr_opts always == 0 here.
> 
> 232         int result;
> 233
> 234         result = 0;
> 235         while ((result == 0) && opt_string && *opt_string) {
> 
> I assume opt_string is not null (opt_string == "tmgr.atom_max_size=2048" ?), 
> so let's loop:
> 
> 236                 int j;
> 237                 char *next;
> 244                 for (j = 0; j < nr_opts; ++j) {
> 
> nr_opts == 0, so we won't do any iteration here.
> 
> 245                         if (!strncmp(opt_string, opts[j].name,
> 246                                      strlen(opts[j].name))) {
> 247                                 result = parse_option(opt_string, &opts[j]);
> 248                                 break;
> 249                         }
> 250                 }
> 
> here, j==0 and nr_opts==0.
> 
> 251                 if (j == nr_opts) {
> 252                         warning("nikita-2307", "Unrecognized option: \"%s\"",
> 253                                 opt_string);
> 254                         /* traditionally, -EINVAL is returned on wrong mount
> 255                            option */
> 256                         result = RETERR(-EINVAL);
> 
> oops !
> 
> ~~
> laurent
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