lkml.org 
[lkml]   [2005]   [Jul]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC PATCH 1/8] share/private/slave a subtree
From
Date
> This patch adds the shared/private/slave support for VFS trees.

[...]

> -struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)
> +struct vfsmount *lookup_mnt(struct vfsmount *mnt, struct dentry *dentry, struct dentry *root)
> {

How about changing it to inline and calling it __lookup_mnt_root(),
and calling it from lookup_mnt() (which could keep the old signature)
and lookup_mnt_root(). That way the compiler can optimize away the
root check for the plain lookup_mnt() case, and there's no need to
modify callers of lookup_mnt().

[...]

>
> +struct vfsmount *do_make_mounted(struct vfsmount *mnt, struct dentry *dentry)
> +{

What does this function do? Can we have a header comment?

> +int
> +_do_make_mounted(struct nameidata *nd, struct vfsmount **mnt)
> +{

Ditto.

> +/*
> + * recursively change the type of the mountpoint.
> + */
> +static int do_change_type(struct nameidata *nd, int flag)
> +{
> + struct vfsmount *m, *mnt;
> + struct vfspnode *old_pnode = NULL;
> + int err;
> +
> + if (!(flag & MS_SHARED) && !(flag & MS_PRIVATE)
> + && !(flag & MS_SLAVE))
> + return -EINVAL;
> +
> + if ((err = _do_make_mounted(nd, &mnt)))
> + return err;


Why does this opertation do any mounting? If it's a type change, it
should just change the type of something already mounted, no?

> + case MS_SHARED:
> + /*
> + * if the mount is already a slave mount,
> + * allocated a new pnode and make it
> + * a slave pnode of the original pnode.
> + */
> + if (IS_MNT_SLAVE(m)) {
> + old_pnode = m->mnt_pnode;
> + pnode_del_slave_mnt(m);
> + }
> + if(!IS_MNT_SHARED(m)) {
> + m->mnt_pnode = pnode_alloc();
> + if(!m->mnt_pnode) {
> + pnode_add_slave_mnt(old_pnode, m);
> + err = -ENOMEM;
> + break;
> + }
> + pnode_add_member_mnt(m->mnt_pnode, m);
> + }
> + if(old_pnode) {
> + pnode_add_slave_pnode(old_pnode,
> + m->mnt_pnode);
> + }
> + SET_MNT_SHARED(m);
> + break;
> +
> + case MS_SLAVE:
> + if (IS_MNT_SLAVE(m)) {
> + break;
> + }
> + /*
> + * only shared mounts can
> + * be made slave
> + */
> + if (!IS_MNT_SHARED(m)) {
> + err = -EINVAL;
> + break;
> + }
> + old_pnode = m->mnt_pnode;
> + pnode_del_member_mnt(m);
> + pnode_add_slave_mnt(old_pnode, m);
> + SET_MNT_SLAVE(m);
> + break;
> +
> + case MS_PRIVATE:
> + if(m->mnt_pnode)
> + pnode_disassociate_mnt(m);
> + SET_MNT_PRIVATE(m);
> + break;
> +

Can this be split into three functions?

[...]

> +/*
> + * Walk the pnode tree for each pnode encountered. A given pnode in the tree
> + * can be returned a minimum of 2 times. First time the pnode is encountered,
> + * it is returned with the flag PNODE_DOWN. Everytime the pnode is encountered
> + * after having traversed through each of its children, it is returned with the
> + * flag PNODE_MID. And finally when the pnode is encountered after having
> + * walked all of its children, it is returned with the flag PNODE_UP.
> + *
> + * @context: provides context on the state of the last walk in the pnode
> + * tree.
> + */
> +static int inline
> +pnode_next(struct pcontext *context)
> +{

Is such a generic traversal function really needed? Why?

[...]

> +struct vfsmount *
> +pnode_make_mounted(struct vfspnode *pnode, struct vfsmount *mnt, struct dentry *dentry)
> +{

Again a header comment would be nice, on what exactly this function
does. Also the implementation is really cryptic, but I can't even
start to decipher without knowing what it's supposed to do.

[...]

> +static inline struct vfspnode *
> +get_pnode_n(struct vfspnode *pnode, size_t n)
> +{

Seems to be unused throughout the patch series

> + struct list_head mnt_pnode_mntlist;/* and going through their
> + pnode's vfsmount */
> + struct vfspnode *mnt_pnode; /* and going through their
> + pnode's vfsmount */
> atomic_t mnt_count;
> int mnt_flags;
> int mnt_expiry_mark; /* true if marked for expiry */
> @@ -38,6 +66,7 @@ struct vfsmount
> struct namespace *mnt_namespace; /* containing namespace */
> };
>
> +
> static inline struct vfsmount *mntget(struct vfsmount *mnt)

Please don't add empty lines.

Miklos
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-07-08 16:36    [W:0.105 / U:1.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site