Hi Eric,
For the past few weeks, I've been trying to port your netns patchset
on top of 2.6.21-mm2. It took me a lot more time than I first expected
to have something working.
I started the port based on your latest public git repository tag:
"netns/v2.6.21-rc6-netns17".
I met a few difficulties during the port the worst being porting the
shadow directories patches on top of Greg's sysfs patches.
Greg modified a lot of things in sysfs and I had to "rewrite"/adapt
most of your "sysfs: Implement sysfs manged shadow directory support"
patch. My knowledge of sysfs approaching zero, the result isn't that
great.
Any chance you've updated the patchset for a recent version of the -mm
kernel?
Here are some issues I have with the sysfs part of the netns patchset:
* The first thing I'm not sure to understand in your patch is how
shadow dirs and there "real" counterpart are supposed to be linked
(via dentry and via sysfs_dirent).
Is it something like:
/sys/class/net/ ("real" net class)
/sys/class/net-shadow1/
/sys/class/net-shadow2/
or:
/sys/class/net/
/sys/class/net/net-shadow1/
/sys/class/net/net-shadow2/
In add_shadow_dir(), it seems the shadow dentry parent is "class" :
shadow = d_alloc(dir->d_parent, &dir->d_name);
and the shadow sysfs_dirent parent is the real "net":
sysfs_make_dirent(dir->d_fsdata, ....);
On 2.6.21-mm2, if I attach the dentry to "class" (dir->d_parent) as
you did initially, then the shadow directory lookup "fails": it
always returns the same shadow dir, whatever network namespace is
current. Indeed, sysfs_shadow_follow_link() is never called with a
SYSFS_DIR dentry, but always directly with a SYSFS_SHADOW one, and the
tag comparison is never done.
In add_shadow_dir(), I changed the d_alloc() call and passed dir
instead of dir->d_parent, and it "solved" the issue:
sysfs_shadow_follow_link() is called with the SYSFS_DIR dentry, and
the shadow dir lookup is done.
* I also have some issues with symlinks.
Indeed, the way symlinks are "resolved" have changed. Symlinks paths
aren't resolved anymore using kobject linking but uses sysfs_dirent
instead. So I had to use a dirty hack to skip shadow directories in
fs/sysfs/symlink.c: fill_object_path()/object_path_length().
Regards.
Benjamin
--
B e n j a m i n T h e r y - BULL/DT/Open Software R&D
http://www.bull.com
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