On 2014/1/15 1:17, Veaceslav Falico wrote:
> Hi,
>
> I'm hitting a strange issue and/or I'm completely lost in sysfs internals.
>
> Consider having two net_device *a, *b; which are registered normally.
> Now, to create a link from /sys/class/net/a->name/linkname to b, one should
> use:
>
> sysfs_create_link(&(a->dev.kobj), &(b->dev.kobj), linkname);
>
> To remove it, even simpler:
>
> sysfs_remove_link(&(a->dev.kobj), linkname);
>
> This works like a charm. However, if I want to use (obviously, with the
> symlink present):
>
> sysfs_rename_link(&(a->dev.kobj), &(b->dev.kobj), oldname, newname);
>
> this fails with:
>
> "sysfs: ns invalid in 'a->name' for 'oldname'"
>
> in
>
> 608 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
> ...
> 615 if (!!sysfs_ns_type(parent_sd) != !!ns) {
> 616 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
> 617 sysfs_ns_type(parent_sd) ? "required" :
> "invalid",
> 618 parent_sd->s_name, name);
> 619 return NULL;
> 620 }
>
> Code path:
> warn_slowpath_fmt+0x46/0x50
> sysfs_get_dirent_ns+0x30/0x80
> sysfs_find_dirent+0x84/0x110
> sysfs_get_dirent_ns+0x3e/0x80
> sysfs_rename_link_ns+0x54/0xd0
>
> I have no idea what this code means. Is there any reason for it to
> fail (i.e. am I doing something wrong?) or I've hit a bug?
>
> I've tested the only user of it (bridge) - and it works fine, however it's
> not using its own net_device's kobject but rather its own dir.
>
I use the sysfs_rename_link(x,x) and meet the same problem, I review the code
for bridge,
I found the br->ifobj was using kobject_create_and_add() to add a subdir for
this, maybe it
helps?
Ding
> Thank you!
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>
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