2019-05-20 19:08:01 +02:00
|
|
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
2018-06-15 16:19:22 +02:00
|
|
|
/* AFS dynamic root handling
|
2018-04-06 15:17:25 +02:00
|
|
|
*
|
|
|
|
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
|
|
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/fs.h>
|
|
|
|
#include <linux/namei.h>
|
|
|
|
#include <linux/dns_resolver.h>
|
|
|
|
#include "internal.h"
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Probe to see if a cell may exist. This prevents positive dentries from
|
|
|
|
* being created unnecessarily.
|
|
|
|
*/
|
|
|
|
static int afs_probe_cell_name(struct dentry *dentry)
|
|
|
|
{
|
|
|
|
struct afs_cell *cell;
|
2019-06-26 22:02:33 +02:00
|
|
|
struct afs_net *net = afs_d2net(dentry);
|
2018-04-06 15:17:25 +02:00
|
|
|
const char *name = dentry->d_name.name;
|
|
|
|
size_t len = dentry->d_name.len;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
/* Names prefixed with a dot are R/W mounts. */
|
|
|
|
if (name[0] == '.') {
|
|
|
|
if (len == 1)
|
|
|
|
return -EINVAL;
|
|
|
|
name++;
|
|
|
|
len--;
|
|
|
|
}
|
|
|
|
|
2019-06-26 22:02:33 +02:00
|
|
|
cell = afs_lookup_cell_rcu(net, name, len);
|
2018-04-06 15:17:25 +02:00
|
|
|
if (!IS_ERR(cell)) {
|
2019-06-26 22:02:33 +02:00
|
|
|
afs_put_cell(net, cell);
|
2018-04-06 15:17:25 +02:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2019-06-26 22:02:33 +02:00
|
|
|
ret = dns_query(net->net, "afsdb", name, len, "srv=1",
|
|
|
|
NULL, NULL, false);
|
2018-04-06 15:17:25 +02:00
|
|
|
if (ret == -ENODATA)
|
|
|
|
ret = -EDESTADDRREQ;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to auto mount the mountpoint with pseudo directory, if the autocell
|
|
|
|
* operation is setted.
|
|
|
|
*/
|
|
|
|
struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
|
|
|
|
{
|
|
|
|
struct afs_vnode *vnode = AFS_FS_I(dir);
|
|
|
|
struct inode *inode;
|
|
|
|
int ret = -ENOENT;
|
|
|
|
|
2018-10-20 01:57:57 +02:00
|
|
|
_enter("%p{%pd}, {%llx:%llu}",
|
2018-04-06 15:17:25 +02:00
|
|
|
dentry, dentry, vnode->fid.vid, vnode->fid.vnode);
|
|
|
|
|
|
|
|
if (!test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
ret = afs_probe_cell_name(dentry);
|
|
|
|
if (ret < 0)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
inode = afs_iget_pseudo_dir(dir->i_sb, false);
|
|
|
|
if (IS_ERR(inode)) {
|
|
|
|
ret = PTR_ERR(inode);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
_leave("= %p", inode);
|
|
|
|
return inode;
|
|
|
|
|
|
|
|
out:
|
|
|
|
_leave("= %d", ret);
|
2018-06-24 16:45:44 +02:00
|
|
|
return ret == -ENOENT ? NULL : ERR_PTR(ret);
|
2018-04-06 15:17:25 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Look up @cell in a dynroot directory. This is a substitution for the
|
|
|
|
* local cell name for the net namespace.
|
|
|
|
*/
|
|
|
|
static struct dentry *afs_lookup_atcell(struct dentry *dentry)
|
|
|
|
{
|
|
|
|
struct afs_cell *cell;
|
|
|
|
struct afs_net *net = afs_d2net(dentry);
|
|
|
|
struct dentry *ret;
|
|
|
|
unsigned int seq = 0;
|
|
|
|
char *name;
|
|
|
|
int len;
|
|
|
|
|
|
|
|
if (!net->ws_cell)
|
|
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
|
|
|
|
ret = ERR_PTR(-ENOMEM);
|
|
|
|
name = kmalloc(AFS_MAXCELLNAME + 1, GFP_KERNEL);
|
|
|
|
if (!name)
|
|
|
|
goto out_p;
|
|
|
|
|
|
|
|
rcu_read_lock();
|
|
|
|
do {
|
|
|
|
read_seqbegin_or_lock(&net->cells_lock, &seq);
|
|
|
|
cell = rcu_dereference_raw(net->ws_cell);
|
|
|
|
if (cell) {
|
|
|
|
len = cell->name_len;
|
|
|
|
memcpy(name, cell->name, len + 1);
|
|
|
|
}
|
|
|
|
} while (need_seqretry(&net->cells_lock, seq));
|
|
|
|
done_seqretry(&net->cells_lock, seq);
|
|
|
|
rcu_read_unlock();
|
|
|
|
|
|
|
|
ret = ERR_PTR(-ENOENT);
|
|
|
|
if (!cell)
|
|
|
|
goto out_n;
|
|
|
|
|
|
|
|
ret = lookup_one_len(name, dentry->d_parent, len);
|
|
|
|
|
|
|
|
/* We don't want to d_add() the @cell dentry here as we don't want to
|
|
|
|
* the cached dentry to hide changes to the local cell name.
|
|
|
|
*/
|
|
|
|
|
|
|
|
out_n:
|
|
|
|
kfree(name);
|
|
|
|
out_p:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Look up an entry in a dynroot directory.
|
|
|
|
*/
|
|
|
|
static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentry,
|
|
|
|
unsigned int flags)
|
|
|
|
{
|
|
|
|
_enter("%pd", dentry);
|
|
|
|
|
|
|
|
ASSERTCMP(d_inode(dentry), ==, NULL);
|
|
|
|
|
2019-12-11 09:56:04 +01:00
|
|
|
if (flags & LOOKUP_CREATE)
|
|
|
|
return ERR_PTR(-EOPNOTSUPP);
|
|
|
|
|
2018-04-06 15:17:25 +02:00
|
|
|
if (dentry->d_name.len >= AFSNAMEMAX) {
|
|
|
|
_leave(" = -ENAMETOOLONG");
|
|
|
|
return ERR_PTR(-ENAMETOOLONG);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (dentry->d_name.len == 5 &&
|
|
|
|
memcmp(dentry->d_name.name, "@cell", 5) == 0)
|
|
|
|
return afs_lookup_atcell(dentry);
|
|
|
|
|
2018-06-24 16:45:44 +02:00
|
|
|
return d_splice_alias(afs_try_auto_mntpt(dentry, dir), dentry);
|
2018-04-06 15:17:25 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
const struct inode_operations afs_dynroot_inode_operations = {
|
|
|
|
.lookup = afs_dynroot_lookup,
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Dirs in the dynamic root don't need revalidation.
|
|
|
|
*/
|
|
|
|
static int afs_dynroot_d_revalidate(struct dentry *dentry, unsigned int flags)
|
|
|
|
{
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
|
|
|
|
* sleep)
|
|
|
|
* - called from dput() when d_count is going to 0.
|
|
|
|
* - return 1 to request dentry be unhashed, 0 otherwise
|
|
|
|
*/
|
|
|
|
static int afs_dynroot_d_delete(const struct dentry *dentry)
|
|
|
|
{
|
|
|
|
return d_really_is_positive(dentry);
|
|
|
|
}
|
|
|
|
|
|
|
|
const struct dentry_operations afs_dynroot_dentry_operations = {
|
|
|
|
.d_revalidate = afs_dynroot_d_revalidate,
|
|
|
|
.d_delete = afs_dynroot_d_delete,
|
|
|
|
.d_release = afs_d_release,
|
|
|
|
.d_automount = afs_d_automount,
|
|
|
|
};
|
2018-06-15 16:19:22 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Create a manually added cell mount directory.
|
|
|
|
* - The caller must hold net->proc_cells_lock
|
|
|
|
*/
|
|
|
|
int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell)
|
|
|
|
{
|
|
|
|
struct super_block *sb = net->dynroot_sb;
|
|
|
|
struct dentry *root, *subdir;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!sb || atomic_read(&sb->s_active) == 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
/* Let the ->lookup op do the creation */
|
|
|
|
root = sb->s_root;
|
|
|
|
inode_lock(root->d_inode);
|
|
|
|
subdir = lookup_one_len(cell->name, root, cell->name_len);
|
|
|
|
if (IS_ERR(subdir)) {
|
|
|
|
ret = PTR_ERR(subdir);
|
|
|
|
goto unlock;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Note that we're retaining an extra ref on the dentry */
|
|
|
|
subdir->d_fsdata = (void *)1UL;
|
|
|
|
ret = 0;
|
|
|
|
unlock:
|
|
|
|
inode_unlock(root->d_inode);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Remove a manually added cell mount directory.
|
|
|
|
* - The caller must hold net->proc_cells_lock
|
|
|
|
*/
|
|
|
|
void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell)
|
|
|
|
{
|
|
|
|
struct super_block *sb = net->dynroot_sb;
|
|
|
|
struct dentry *root, *subdir;
|
|
|
|
|
|
|
|
if (!sb || atomic_read(&sb->s_active) == 0)
|
|
|
|
return;
|
|
|
|
|
|
|
|
root = sb->s_root;
|
|
|
|
inode_lock(root->d_inode);
|
|
|
|
|
|
|
|
/* Don't want to trigger a lookup call, which will re-add the cell */
|
|
|
|
subdir = try_lookup_one_len(cell->name, root, cell->name_len);
|
|
|
|
if (IS_ERR_OR_NULL(subdir)) {
|
|
|
|
_debug("lookup %ld", PTR_ERR(subdir));
|
|
|
|
goto no_dentry;
|
|
|
|
}
|
|
|
|
|
|
|
|
_debug("rmdir %pd %u", subdir, d_count(subdir));
|
|
|
|
|
|
|
|
if (subdir->d_fsdata) {
|
|
|
|
_debug("unpin %u", d_count(subdir));
|
|
|
|
subdir->d_fsdata = NULL;
|
|
|
|
dput(subdir);
|
|
|
|
}
|
|
|
|
dput(subdir);
|
|
|
|
no_dentry:
|
|
|
|
inode_unlock(root->d_inode);
|
|
|
|
_leave("");
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Populate a newly created dynamic root with cell names.
|
|
|
|
*/
|
|
|
|
int afs_dynroot_populate(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct afs_cell *cell;
|
|
|
|
struct afs_net *net = afs_sb2net(sb);
|
|
|
|
int ret;
|
|
|
|
|
2019-05-09 10:17:08 +02:00
|
|
|
mutex_lock(&net->proc_cells_lock);
|
2018-06-15 16:19:22 +02:00
|
|
|
|
|
|
|
net->dynroot_sb = sb;
|
2018-10-11 23:45:49 +02:00
|
|
|
hlist_for_each_entry(cell, &net->proc_cells, proc_link) {
|
2018-06-15 16:19:22 +02:00
|
|
|
ret = afs_dynroot_mkdir(net, cell);
|
|
|
|
if (ret < 0)
|
|
|
|
goto error;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
|
|
mutex_unlock(&net->proc_cells_lock);
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
error:
|
|
|
|
net->dynroot_sb = NULL;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* When a dynamic root that's in the process of being destroyed, depopulate it
|
|
|
|
* of pinned directories.
|
|
|
|
*/
|
|
|
|
void afs_dynroot_depopulate(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct afs_net *net = afs_sb2net(sb);
|
|
|
|
struct dentry *root = sb->s_root, *subdir, *tmp;
|
|
|
|
|
|
|
|
/* Prevent more subdirs from being created */
|
|
|
|
mutex_lock(&net->proc_cells_lock);
|
|
|
|
if (net->dynroot_sb == sb)
|
|
|
|
net->dynroot_sb = NULL;
|
|
|
|
mutex_unlock(&net->proc_cells_lock);
|
|
|
|
|
|
|
|
inode_lock(root->d_inode);
|
|
|
|
|
|
|
|
/* Remove all the pins for dirs created for manually added cells */
|
|
|
|
list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) {
|
|
|
|
if (subdir->d_fsdata) {
|
|
|
|
subdir->d_fsdata = NULL;
|
|
|
|
dput(subdir);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
inode_unlock(root->d_inode);
|
|
|
|
}
|