/*
* nfs_follow_mountpoint - handle crossing a mountpoint on the server
* @dentry - dentry of mountpoint
* @nd - nameidata info
*
* When we encounter a mountpoint on the server, we want to set up
* a mountpoint on the client too, to prevent inode numbers from
* colliding, and to allow "df" to work properly.
* On NFSv4, we also want to allow for the fact that different
* filesystems may be migrated to different servers in a failover
* situation, and that different filesystems may want to use
* different security flavours.
*/
static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *mnt;
struct nfs_server *server = NFS_SERVER(dentry->d_inode);
struct dentry *parent;
struct nfs_fh fh;
struct nfs_fattr fattr;
int err;
dprintk("--> nfs_follow_mountpoint()\n");
BUG_ON(IS_ROOT(dentry));
dprintk("%s: enter\n", __FUNCTION__);
dput(nd->dentry);
nd->dentry = dget(dentry);
/* Look it up again */
parent = dget_parent(nd->dentry);
err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
&nd->dentry->d_name,
&fh, &fattr);
dput(parent);
if (err != 0)
goto out_err;
if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(nd->mnt, nd->dentry);
else
mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr);
err = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out_err;
mntget(mnt);
err = do_add_mount(mnt, nd, nd->mnt->mnt_flags|MNT_SHRINKABLE, &nfs_automount_list);
if (err < 0) {
mntput(mnt);
if (err == -EBUSY)
goto out_follow;
goto out_err;
}
mntput(nd->mnt);
dput(nd->dentry);
nd->mnt = mnt;
nd->dentry = dget(mnt->mnt_root);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
dprintk("%s: done, returned %d\n", __FUNCTION__, err);
dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
return ERR_PTR(err);
out_err:
path_release(nd);
goto out;
out_follow:
while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
;
err = 0;
goto out;
}
/*
* nfs_d_automount - Handle crossing a mountpoint on the server
* @path - The mountpoint
*
* When we encounter a mountpoint on the server, we want to set up
* a mountpoint on the client too, to prevent inode numbers from
* colliding, and to allow "df" to work properly.
* On NFSv4, we also want to allow for the fact that different
* filesystems may be migrated to different servers in a failover
* situation, and that different filesystems may want to use
* different security flavours.
*/
struct vfsmount *nfs_d_automount(struct path *path)
{
struct vfsmount *mnt;
struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
struct dentry *parent;
struct nfs_fh *fh = NULL;
struct nfs_fattr *fattr = NULL;
int err;
rpc_authflavor_t flavor = RPC_AUTH_UNIX;
dprintk("--> nfs_d_automount()\n");
mnt = ERR_PTR(-ESTALE);
if (IS_ROOT(path->dentry))
goto out_nofree;
mnt = ERR_PTR(-ENOMEM);
fh = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fh == NULL || fattr == NULL)
goto out;
dprintk("%s: enter\n", __func__);
/* Look it up again to get its attributes */
parent = dget_parent(path->dentry);
err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
&path->dentry->d_name,
fh, fattr);
if (err == -EPERM && NFS_PROTO(parent->d_inode)->secinfo != NULL)
err = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr, &flavor);
dput(parent);
if (err != 0) {
mnt = ERR_PTR(err);
goto out;
}
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(path->dentry);
else
mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
if (IS_ERR(mnt))
goto out;
dprintk("%s: done, success\n", __func__);
mntget(mnt); /* prevent immediate expiration */
mnt_set_expiry(mnt, &nfs_automount_list);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fh);
out_nofree:
dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt);
return mnt;
}
struct vfsmount *nfs_d_automount(struct path *path)
{
struct vfsmount *mnt;
struct dentry *parent;
struct nfs_fh *fh = NULL;
struct nfs_fattr *fattr = NULL;
struct rpc_clnt *client;
dprintk("--> nfs_d_automount()\n");
mnt = ERR_PTR(-ESTALE);
if (IS_ROOT(path->dentry))
goto out_nofree;
mnt = ERR_PTR(-ENOMEM);
fh = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fh == NULL || fattr == NULL)
goto out;
dprintk("%s: enter\n", __func__);
parent = dget_parent(path->dentry);
client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr);
dput(parent);
if (IS_ERR(client)) {
mnt = ERR_CAST(client);
goto out;
}
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(client, path->dentry);
else
mnt = nfs_do_submount(path->dentry, fh, fattr, client->cl_auth->au_flavor);
rpc_shutdown_client(client);
if (IS_ERR(mnt))
goto out;
dprintk("%s: done, success\n", __func__);
mntget(mnt);
mnt_set_expiry(mnt, &nfs_automount_list);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fh);
out_nofree:
if (IS_ERR(mnt))
dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
else
dprintk("<-- %s() = %p\n", __func__, mnt);
return mnt;
}
/**
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
* @dentry - parent directory
* @locations - array of NFSv4 server location information
*
*/
static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
const struct nfs4_fs_locations *locations)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
struct nfs_clone_mount mountdata = {
.sb = dentry->d_sb,
.dentry = dentry,
.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
};
char *page = NULL, *page2 = NULL;
int loc, error;
if (locations == NULL || locations->nlocations <= 0)
goto out;
dprintk("%s: referral at %s/%s\n", __func__,
dentry->d_parent->d_name.name, dentry->d_name.name);
page = (char *) __get_free_page(GFP_USER);
if (!page)
goto out;
page2 = (char *) __get_free_page(GFP_USER);
if (!page2)
goto out;
/* Ensure fs path is a prefix of current dentry path */
error = nfs4_validate_fspath(dentry, locations, page, page2);
if (error < 0) {
mnt = ERR_PTR(error);
goto out;
}
for (loc = 0; loc < locations->nlocations; loc++) {
const struct nfs4_fs_location *location = &locations->locations[loc];
if (location == NULL || location->nservers <= 0 ||
location->rootpath.ncomponents == 0)
continue;
mnt = try_location(&mountdata, page, page2, location);
if (!IS_ERR(mnt))
break;
}
out:
free_page((unsigned long) page);
free_page((unsigned long) page2);
dprintk("%s: done\n", __func__);
return mnt;
}
/*
* nfs_do_refmount - handle crossing a referral on server
* @dentry - dentry of referral
*
*/
static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
{
struct vfsmount *mnt = ERR_PTR(-ENOMEM);
struct dentry *parent;
struct nfs4_fs_locations *fs_locations = NULL;
struct page *page;
int err;
/* BUG_ON(IS_ROOT(dentry)); */
dprintk("%s: enter\n", __func__);
page = alloc_page(GFP_KERNEL);
if (page == NULL)
goto out;
fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
if (fs_locations == NULL)
goto out_free;
/* Get locations */
mnt = ERR_PTR(-ENOENT);
parent = dget_parent(dentry);
dprintk("%s: getting locations for %s/%s\n",
__func__, parent->d_name.name, dentry->d_name.name);
err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
dput(parent);
if (err != 0 ||
fs_locations->nlocations <= 0 ||
fs_locations->fs_path.ncomponents <= 0)
goto out_free;
mnt = nfs_follow_referral(dentry, fs_locations);
out_free:
__free_page(page);
kfree(fs_locations);
out:
dprintk("%s: done\n", __func__);
return mnt;
}
struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
struct nfs_fh *fh, struct nfs_fattr *fattr)
{
struct dentry *parent = dget_parent(dentry);
struct rpc_clnt *client;
struct vfsmount *mnt;
/* Look it up again to get its attributes and sec flavor */
client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr);
dput(parent);
if (IS_ERR(client))
return ERR_CAST(client);
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(client, dentry);
else
mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor);
rpc_shutdown_client(client);
return mnt;
}
static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
{
struct vfsmount *mnt;
struct nfs_server *server = NFS_SERVER(dentry->d_inode);
struct dentry *parent;
struct nfs_fh *fh = NULL;
struct nfs_fattr *fattr = NULL;
int err;
dprintk("--> nfs_follow_mountpoint()\n");
err = -ESTALE;
if (IS_ROOT(dentry))
goto out_err;
err = -ENOMEM;
fh = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr();
if (fh == NULL || fattr == NULL)
goto out_err;
dprintk("%s: enter\n", __func__);
dput(nd->path.dentry);
nd->path.dentry = dget(dentry);
/* Look it up again */
parent = dget_parent(nd->path.dentry);
err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
&nd->path.dentry->d_name,
fh, fattr);
dput(parent);
if (err != 0)
goto out_err;
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry);
else
mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh,
fattr);
err = PTR_ERR(mnt);
if (IS_ERR(mnt))
goto out_err;
mntget(mnt);
err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE,
&nfs_automount_list);
if (err < 0) {
mntput(mnt);
if (err == -EBUSY)
goto out_follow;
goto out_err;
}
path_put(&nd->path);
nd->path.mnt = mnt;
nd->path.dentry = dget(mnt->mnt_root);
schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
out:
nfs_free_fattr(fattr);
nfs_free_fhandle(fh);
dprintk("%s: done, returned %d\n", __func__, err);
dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
return ERR_PTR(err);
out_err:
path_put(&nd->path);
goto out;
out_follow:
while (d_mountpoint(nd->path.dentry) &&
follow_down(&nd->path))
;
err = 0;
goto out;
}