Hey,
On Mon, Feb 17, 2014 at 11:54:59AM +0800, Li Zefan wrote:
> I think we have to fix kernfs in order to fix refcnt leak in sysfs
> and cgroupfs. This fix is for 3.14, but it creates conflicts for
> cgroup-next.
>
> ====================
>
> As mount() and kill_sb() is not a one-to-one match, we shoudn't get
> ns refcnt unconditionally in sysfs_mount(), and instead we should
> get the refcnt only when kernfs_mount() allocated a new superblock.
Ugh... nasty :(
> @@ -132,6 +132,7 @@ const void *kernfs_super_ns(struct super_block *sb)
> * @flags: mount flags specified for the mount
> * @root: kernfs_root of the hierarchy being mounted
> * @ns: optional namespace tag of the mount
> + * @new: tell the caller if we allocated a new superblock
Maybe something like @new_sb_created is better?
> struct super_block *sb;
> struct kernfs_super_info *info;
> int error;
>
> + *new_sb = false;
Can we make it optional so that users who don't care about it can
ignore it?
> @@ -430,9 +431,9 @@ static inline int kernfs_rename(struct kernfs_node *kn,
>
> static inline struct dentry *
> kernfs_mount(struct file_system_type *fs_type, int flags,
> - struct kernfs_root *root)
> + struct kernfs_root *root, bool *new_sb)
> {
> - return kernfs_mount_ns(fs_type, flags, root, NULL);
> + return kernfs_mount_ns(fs_type, flags, root, NULL, new_sb);
And let kernfs_mount() just use NULL for the parameter?
Thanks.
--
tejun
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