kernel-ark/fs/nfs/idmap.c
Trond Myklebust 58df095b73 NFSv4: Allow entries in the idmap cache to expire
If someone changes the uid/gid mapping in userland, then we do eventually
 want those changes to be propagated to the kernel. Currently the kernel
 assumes that it may cache entries forever.

 Add an expiration time + garbage collector for idmap entries.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:58 -05:00

509 lines
13 KiB
C

/*
* fs/nfs/idmap.c
*
* UID and GID to name mapping for clients.
*
* Copyright (c) 2002 The Regents of the University of Michigan.
* All rights reserved.
*
* Marius Aamodt Eriksen <marius@umich.edu>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/sched.h>
#include <linux/sunrpc/clnt.h>
#include <linux/workqueue.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_idmap.h>
#include "nfs4_fs.h"
#define IDMAP_HASH_SZ 128
/* Default cache timeout is 10 minutes */
unsigned int nfs_idmap_cache_timeout = 600 * HZ;
struct idmap_hashent {
unsigned long ih_expires;
__u32 ih_id;
int ih_namelen;
char ih_name[IDMAP_NAMESZ];
};
struct idmap_hashtable {
__u8 h_type;
struct idmap_hashent h_entries[IDMAP_HASH_SZ];
};
struct idmap {
char idmap_path[48];
struct dentry *idmap_dentry;
wait_queue_head_t idmap_wq;
struct idmap_msg idmap_im;
struct semaphore idmap_lock; /* Serializes upcalls */
struct semaphore idmap_im_lock; /* Protects the hashtable */
struct idmap_hashtable idmap_user_hash;
struct idmap_hashtable idmap_group_hash;
};
static ssize_t idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
char __user *, size_t);
static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
size_t);
static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
static unsigned int fnvhash32(const void *, size_t);
static struct rpc_pipe_ops idmap_upcall_ops = {
.upcall = idmap_pipe_upcall,
.downcall = idmap_pipe_downcall,
.destroy_msg = idmap_pipe_destroy_msg,
};
void
nfs_idmap_new(struct nfs4_client *clp)
{
struct idmap *idmap;
if (clp->cl_idmap != NULL)
return;
if ((idmap = kmalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
return;
memset(idmap, 0, sizeof(*idmap));
snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
"%s/idmap", clp->cl_rpcclient->cl_pathname);
idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
idmap, &idmap_upcall_ops, 0);
if (IS_ERR(idmap->idmap_dentry)) {
kfree(idmap);
return;
}
init_MUTEX(&idmap->idmap_lock);
init_MUTEX(&idmap->idmap_im_lock);
init_waitqueue_head(&idmap->idmap_wq);
idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
clp->cl_idmap = idmap;
}
void
nfs_idmap_delete(struct nfs4_client *clp)
{
struct idmap *idmap = clp->cl_idmap;
if (!idmap)
return;
rpc_unlink(idmap->idmap_path);
clp->cl_idmap = NULL;
kfree(idmap);
}
/*
* Helper routines for manipulating the hashtable
*/
static inline struct idmap_hashent *
idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
{
return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
}
static struct idmap_hashent *
idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
{
struct idmap_hashent *he = idmap_name_hash(h, name, len);
if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
return NULL;
return he;
}
static inline struct idmap_hashent *
idmap_id_hash(struct idmap_hashtable* h, __u32 id)
{
return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
}
static struct idmap_hashent *
idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
{
struct idmap_hashent *he = idmap_id_hash(h, id);
if (he->ih_id != id || he->ih_namelen == 0)
return NULL;
if (time_after(jiffies, he->ih_expires))
return NULL;
return he;
}
/*
* Routines for allocating new entries in the hashtable.
* For now, we just have 1 entry per bucket, so it's all
* pretty trivial.
*/
static inline struct idmap_hashent *
idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
{
return idmap_name_hash(h, name, len);
}
static inline struct idmap_hashent *
idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
{
return idmap_id_hash(h, id);
}
static void
idmap_update_entry(struct idmap_hashent *he, const char *name,
size_t namelen, __u32 id)
{
he->ih_id = id;
memcpy(he->ih_name, name, namelen);
he->ih_name[namelen] = '\0';
he->ih_namelen = namelen;
he->ih_expires = jiffies + nfs_idmap_cache_timeout;
}
/*
* Name -> ID
*/
static int
nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
const char *name, size_t namelen, __u32 *id)
{
struct rpc_pipe_msg msg;
struct idmap_msg *im;
struct idmap_hashent *he;
DECLARE_WAITQUEUE(wq, current);
int ret = -EIO;
im = &idmap->idmap_im;
/*
* String sanity checks
* Note that the userland daemon expects NUL terminated strings
*/
for (;;) {
if (namelen == 0)
return -EINVAL;
if (name[namelen-1] != '\0')
break;
namelen--;
}
if (namelen >= IDMAP_NAMESZ)
return -EINVAL;
down(&idmap->idmap_lock);
down(&idmap->idmap_im_lock);
he = idmap_lookup_name(h, name, namelen);
if (he != NULL) {
*id = he->ih_id;
ret = 0;
goto out;
}
memset(im, 0, sizeof(*im));
memcpy(im->im_name, name, namelen);
im->im_type = h->h_type;
im->im_conv = IDMAP_CONV_NAMETOID;
memset(&msg, 0, sizeof(msg));
msg.data = im;
msg.len = sizeof(*im);
add_wait_queue(&idmap->idmap_wq, &wq);
if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
remove_wait_queue(&idmap->idmap_wq, &wq);
goto out;
}
set_current_state(TASK_UNINTERRUPTIBLE);
up(&idmap->idmap_im_lock);
schedule();
current->state = TASK_RUNNING;
remove_wait_queue(&idmap->idmap_wq, &wq);
down(&idmap->idmap_im_lock);
if (im->im_status & IDMAP_STATUS_SUCCESS) {
*id = im->im_id;
ret = 0;
}
out:
memset(im, 0, sizeof(*im));
up(&idmap->idmap_im_lock);
up(&idmap->idmap_lock);
return (ret);
}
/*
* ID -> Name
*/
static int
nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
__u32 id, char *name)
{
struct rpc_pipe_msg msg;
struct idmap_msg *im;
struct idmap_hashent *he;
DECLARE_WAITQUEUE(wq, current);
int ret = -EIO;
unsigned int len;
im = &idmap->idmap_im;
down(&idmap->idmap_lock);
down(&idmap->idmap_im_lock);
he = idmap_lookup_id(h, id);
if (he != 0) {
memcpy(name, he->ih_name, he->ih_namelen);
ret = he->ih_namelen;
goto out;
}
memset(im, 0, sizeof(*im));
im->im_type = h->h_type;
im->im_conv = IDMAP_CONV_IDTONAME;
im->im_id = id;
memset(&msg, 0, sizeof(msg));
msg.data = im;
msg.len = sizeof(*im);
add_wait_queue(&idmap->idmap_wq, &wq);
if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
remove_wait_queue(&idmap->idmap_wq, &wq);
goto out;
}
set_current_state(TASK_UNINTERRUPTIBLE);
up(&idmap->idmap_im_lock);
schedule();
current->state = TASK_RUNNING;
remove_wait_queue(&idmap->idmap_wq, &wq);
down(&idmap->idmap_im_lock);
if (im->im_status & IDMAP_STATUS_SUCCESS) {
if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
goto out;
memcpy(name, im->im_name, len);
ret = len;
}
out:
memset(im, 0, sizeof(*im));
up(&idmap->idmap_im_lock);
up(&idmap->idmap_lock);
return ret;
}
/* RPC pipefs upcall/downcall routines */
static ssize_t
idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
char __user *dst, size_t buflen)
{
char *data = (char *)msg->data + msg->copied;
ssize_t mlen = msg->len - msg->copied;
ssize_t left;
if (mlen > buflen)
mlen = buflen;
left = copy_to_user(dst, data, mlen);
if (left < 0) {
msg->errno = left;
return left;
}
mlen -= left;
msg->copied += mlen;
msg->errno = 0;
return mlen;
}
static ssize_t
idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
{
struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
struct idmap *idmap = (struct idmap *)rpci->private;
struct idmap_msg im_in, *im = &idmap->idmap_im;
struct idmap_hashtable *h;
struct idmap_hashent *he = NULL;
int namelen_in;
int ret;
if (mlen != sizeof(im_in))
return (-ENOSPC);
if (copy_from_user(&im_in, src, mlen) != 0)
return (-EFAULT);
down(&idmap->idmap_im_lock);
ret = mlen;
im->im_status = im_in.im_status;
/* If we got an error, terminate now, and wake up pending upcalls */
if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
wake_up(&idmap->idmap_wq);
goto out;
}
/* Sanity checking of strings */
ret = -EINVAL;
namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
goto out;
switch (im_in.im_type) {
case IDMAP_TYPE_USER:
h = &idmap->idmap_user_hash;
break;
case IDMAP_TYPE_GROUP:
h = &idmap->idmap_group_hash;
break;
default:
goto out;
}
switch (im_in.im_conv) {
case IDMAP_CONV_IDTONAME:
/* Did we match the current upcall? */
if (im->im_conv == IDMAP_CONV_IDTONAME
&& im->im_type == im_in.im_type
&& im->im_id == im_in.im_id) {
/* Yes: copy string, including the terminating '\0' */
memcpy(im->im_name, im_in.im_name, namelen_in);
im->im_name[namelen_in] = '\0';
wake_up(&idmap->idmap_wq);
}
he = idmap_alloc_id(h, im_in.im_id);
break;
case IDMAP_CONV_NAMETOID:
/* Did we match the current upcall? */
if (im->im_conv == IDMAP_CONV_NAMETOID
&& im->im_type == im_in.im_type
&& strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
&& memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
im->im_id = im_in.im_id;
wake_up(&idmap->idmap_wq);
}
he = idmap_alloc_name(h, im_in.im_name, namelen_in);
break;
default:
goto out;
}
/* If the entry is valid, also copy it to the cache */
if (he != NULL)
idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
ret = mlen;
out:
up(&idmap->idmap_im_lock);
return ret;
}
static void
idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
{
struct idmap_msg *im = msg->data;
struct idmap *idmap = container_of(im, struct idmap, idmap_im);
if (msg->errno >= 0)
return;
down(&idmap->idmap_im_lock);
im->im_status = IDMAP_STATUS_LOOKUPFAIL;
wake_up(&idmap->idmap_wq);
up(&idmap->idmap_im_lock);
}
/*
* Fowler/Noll/Vo hash
* http://www.isthe.com/chongo/tech/comp/fnv/
*/
#define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
#define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
static unsigned int fnvhash32(const void *buf, size_t buflen)
{
const unsigned char *p, *end = (const unsigned char *)buf + buflen;
unsigned int hash = FNV_1_32;
for (p = buf; p < end; p++) {
hash *= FNV_P_32;
hash ^= (unsigned int)*p;
}
return (hash);
}
int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
}
int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
}
int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
}
int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
{
struct idmap *idmap = clp->cl_idmap;
return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
}