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0b524123c9
linux/fs/nfs/mount_clnt.c
Chuck Lever 0b524123c9 NFS: Add ability to send MOUNTPROC_UMNT to the kernel's mountd client 
After certain failure modes of an NFS mount, an NFS client should send
a MOUNTPROC_UMNT request to remove the just-added mount entry from the
server's mount table.  While no-one should rely on the accuracy of the
server's mount table, sending a UMNT is simply being a good internet
neighbor.

Since NFS mount processing is handled in the kernel now, we will need
a function in the kernel's mountd client that can post a MOUNTRPC_UMNT
request, in order to handle these failure modes.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-08-09 15:09:30 -04:00

532 lines
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/*
* In-kernel MOUNT protocol client
*
* Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/uio.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#include <linux/nfs_fs.h>
#include "internal.h"
#ifdef RPC_DEBUG
# define NFSDBG_FACILITY NFSDBG_MOUNT
#endif
/*
* Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
*/
#define MNTPATHLEN (1024)
/*
* XDR data type sizes
*/
#define encode_dirpath_sz (1 + XDR_QUADLEN(MNTPATHLEN))
#define MNT_status_sz (1)
#define MNT_fhs_status_sz (1)
#define MNT_fhandle_sz XDR_QUADLEN(NFS2_FHSIZE)
#define MNT_fhandle3_sz (1 + XDR_QUADLEN(NFS3_FHSIZE))
#define MNT_authflav3_sz (1 + NFS_MAX_SECFLAVORS)
/*
* XDR argument and result sizes
*/
#define MNT_enc_dirpath_sz encode_dirpath_sz
#define MNT_dec_mountres_sz (MNT_status_sz + MNT_fhandle_sz)
#define MNT_dec_mountres3_sz (MNT_status_sz + MNT_fhandle_sz + \
MNT_authflav3_sz)
/*
* Defined by RFC 1094, section A.5
*/
enum {
MOUNTPROC_NULL = 0,
MOUNTPROC_MNT = 1,
MOUNTPROC_DUMP = 2,
MOUNTPROC_UMNT = 3,
MOUNTPROC_UMNTALL = 4,
MOUNTPROC_EXPORT = 5,
};
/*
* Defined by RFC 1813, section 5.2
*/
enum {
MOUNTPROC3_NULL = 0,
MOUNTPROC3_MNT = 1,
MOUNTPROC3_DUMP = 2,
MOUNTPROC3_UMNT = 3,
MOUNTPROC3_UMNTALL = 4,
MOUNTPROC3_EXPORT = 5,
};
static struct rpc_program mnt_program;
/*
* Defined by OpenGroup XNFS Version 3W, chapter 8
*/
enum mountstat {
MNT_OK = 0,
MNT_EPERM = 1,
MNT_ENOENT = 2,
MNT_EACCES = 13,
MNT_EINVAL = 22,
};
static struct {
u32 status;
int errno;
} mnt_errtbl[] = {
{ .status = MNT_OK, .errno = 0, },
{ .status = MNT_EPERM, .errno = -EPERM, },
{ .status = MNT_ENOENT, .errno = -ENOENT, },
{ .status = MNT_EACCES, .errno = -EACCES, },
{ .status = MNT_EINVAL, .errno = -EINVAL, },
};
/*
* Defined by RFC 1813, section 5.1.5
*/
enum mountstat3 {
MNT3_OK = 0, /* no error */
MNT3ERR_PERM = 1, /* Not owner */
MNT3ERR_NOENT = 2, /* No such file or directory */
MNT3ERR_IO = 5, /* I/O error */
MNT3ERR_ACCES = 13, /* Permission denied */
MNT3ERR_NOTDIR = 20, /* Not a directory */
MNT3ERR_INVAL = 22, /* Invalid argument */
MNT3ERR_NAMETOOLONG = 63, /* Filename too long */
MNT3ERR_NOTSUPP = 10004, /* Operation not supported */
MNT3ERR_SERVERFAULT = 10006, /* A failure on the server */
};
static struct {
u32 status;
int errno;
} mnt3_errtbl[] = {
{ .status = MNT3_OK, .errno = 0, },
{ .status = MNT3ERR_PERM, .errno = -EPERM, },
{ .status = MNT3ERR_NOENT, .errno = -ENOENT, },
{ .status = MNT3ERR_IO, .errno = -EIO, },
{ .status = MNT3ERR_ACCES, .errno = -EACCES, },
{ .status = MNT3ERR_NOTDIR, .errno = -ENOTDIR, },
{ .status = MNT3ERR_INVAL, .errno = -EINVAL, },
{ .status = MNT3ERR_NAMETOOLONG, .errno = -ENAMETOOLONG, },
{ .status = MNT3ERR_NOTSUPP, .errno = -ENOTSUPP, },
{ .status = MNT3ERR_SERVERFAULT, .errno = -ESERVERFAULT, },
};
struct mountres {
int errno;
struct nfs_fh *fh;
unsigned int *auth_count;
rpc_authflavor_t *auth_flavors;
};
struct mnt_fhstatus {
u32 status;
struct nfs_fh *fh;
};
/**
* nfs_mount - Obtain an NFS file handle for the given host and path
* @info: pointer to mount request arguments
*
* Uses default timeout parameters specified by underlying transport.
*/
int nfs_mount(struct nfs_mount_request *info)
{
struct mountres result = {
.fh = info->fh,
.auth_count = info->auth_flav_len,
.auth_flavors = info->auth_flavs,
};
struct rpc_message msg = {
.rpc_argp = info->dirpath,
.rpc_resp = &result,
};
struct rpc_create_args args = {
.protocol = info->protocol,
.address = info->sap,
.addrsize = info->salen,
.servername = info->hostname,
.program = &mnt_program,
.version = info->version,
.authflavor = RPC_AUTH_UNIX,
};
struct rpc_clnt *mnt_clnt;
int status;
dprintk("NFS: sending MNT request for %s:%s\n",
(info->hostname ? info->hostname : "server"),
info->dirpath);
if (info->noresvport)
args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
mnt_clnt = rpc_create(&args);
if (IS_ERR(mnt_clnt))
goto out_clnt_err;
if (info->version == NFS_MNT3_VERSION)
msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
else
msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
status = rpc_call_sync(mnt_clnt, &msg, 0);
rpc_shutdown_client(mnt_clnt);
if (status < 0)
goto out_call_err;
if (result.errno != 0)
goto out_mnt_err;
dprintk("NFS: MNT request succeeded\n");
status = 0;
out:
return status;
out_clnt_err:
status = PTR_ERR(mnt_clnt);
dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
goto out;
out_call_err:
dprintk("NFS: MNT request failed, status=%d\n", status);
goto out;
out_mnt_err:
dprintk("NFS: MNT server returned result %d\n", result.errno);
status = result.errno;
goto out;
}
/**
* nfs_umount - Notify a server that we have unmounted this export
* @info: pointer to umount request arguments
*
* MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
* use UDP.
*/
void nfs_umount(const struct nfs_mount_request *info)
{
static const struct rpc_timeout nfs_umnt_timeout = {
.to_initval = 1 * HZ,
.to_maxval = 3 * HZ,
.to_retries = 2,
};
struct rpc_create_args args = {
.protocol = IPPROTO_UDP,
.address = info->sap,
.addrsize = info->salen,
.timeout = &nfs_umnt_timeout,
.servername = info->hostname,
.program = &mnt_program,
.version = info->version,
.authflavor = RPC_AUTH_UNIX,
.flags = RPC_CLNT_CREATE_NOPING,
};
struct mountres result;
struct rpc_message msg = {
.rpc_argp = info->dirpath,
.rpc_resp = &result,
};
struct rpc_clnt *clnt;
int status;
if (info->noresvport)
args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
clnt = rpc_create(&args);
if (unlikely(IS_ERR(clnt)))
goto out_clnt_err;
dprintk("NFS: sending UMNT request for %s:%s\n",
(info->hostname ? info->hostname : "server"), info->dirpath);
if (info->version == NFS_MNT3_VERSION)
msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
else
msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
status = rpc_call_sync(clnt, &msg, 0);
rpc_shutdown_client(clnt);
if (unlikely(status < 0))
goto out_call_err;
return;
out_clnt_err:
dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
PTR_ERR(clnt));
return;
out_call_err:
dprintk("NFS: UMNT request failed, status=%d\n", status);
}
/*
* XDR encode/decode functions for MOUNT
*/
static int encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
{
const u32 pathname_len = strlen(pathname);
__be32 *p;
if (unlikely(pathname_len > MNTPATHLEN))
return -EIO;
p = xdr_reserve_space(xdr, sizeof(u32) + pathname_len);
if (unlikely(p == NULL))
return -EIO;
xdr_encode_opaque(p, pathname, pathname_len);
return 0;
}
static int mnt_enc_dirpath(struct rpc_rqst *req, __be32 *p,
const char *dirpath)
{
struct xdr_stream xdr;
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
return encode_mntdirpath(&xdr, dirpath);
}
/*
* RFC 1094: "A non-zero status indicates some sort of error. In this
* case, the status is a UNIX error number." This can be problematic
* if the server and client use different errno values for the same
* error.
*
* However, the OpenGroup XNFS spec provides a simple mapping that is
* independent of local errno values on the server and the client.
*/
static int decode_status(struct xdr_stream *xdr, struct mountres *res)
{
unsigned int i;
u32 status;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(status));
if (unlikely(p == NULL))
return -EIO;
status = ntohl(*p);
for (i = 0; i <= ARRAY_SIZE(mnt_errtbl); i++) {
if (mnt_errtbl[i].status == status) {
res->errno = mnt_errtbl[i].errno;
return 0;
}
}
dprintk("NFS: unrecognized MNT status code: %u\n", status);
res->errno = -EACCES;
return 0;
}
static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
{
struct nfs_fh *fh = res->fh;
__be32 *p;
p = xdr_inline_decode(xdr, NFS2_FHSIZE);
if (unlikely(p == NULL))
return -EIO;
fh->size = NFS2_FHSIZE;
memcpy(fh->data, p, NFS2_FHSIZE);
return 0;
}
static int mnt_dec_mountres(struct rpc_rqst *req, __be32 *p,
struct mountres *res)
{
struct xdr_stream xdr;
int status;
xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
status = decode_status(&xdr, res);
if (unlikely(status != 0 || res->errno != 0))
return status;
return decode_fhandle(&xdr, res);
}
static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
{
unsigned int i;
u32 status;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(status));
if (unlikely(p == NULL))
return -EIO;
status = ntohl(*p);
for (i = 0; i <= ARRAY_SIZE(mnt3_errtbl); i++) {
if (mnt3_errtbl[i].status == status) {
res->errno = mnt3_errtbl[i].errno;
return 0;
}
}
dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
res->errno = -EACCES;
return 0;
}
static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
{
struct nfs_fh *fh = res->fh;
u32 size;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(size));
if (unlikely(p == NULL))
return -EIO;
size = ntohl(*p++);
if (size > NFS3_FHSIZE || size == 0)
return -EIO;
p = xdr_inline_decode(xdr, size);
if (unlikely(p == NULL))
return -EIO;
fh->size = size;
memcpy(fh->data, p, size);
return 0;
}
static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
{
rpc_authflavor_t *flavors = res->auth_flavors;
unsigned int *count = res->auth_count;
u32 entries, i;
__be32 *p;
if (*count == 0)
return 0;
p = xdr_inline_decode(xdr, sizeof(entries));
if (unlikely(p == NULL))
return -EIO;
entries = ntohl(*p);
dprintk("NFS: received %u auth flavors\n", entries);
if (entries > NFS_MAX_SECFLAVORS)
entries = NFS_MAX_SECFLAVORS;
p = xdr_inline_decode(xdr, sizeof(u32) * entries);
if (unlikely(p == NULL))
return -EIO;
if (entries > *count)
entries = *count;
for (i = 0; i < entries; i++) {
flavors[i] = ntohl(*p++);
dprintk("NFS:\tflavor %u: %d\n", i, flavors[i]);
}
*count = i;
return 0;
}
static int mnt_dec_mountres3(struct rpc_rqst *req, __be32 *p,
struct mountres *res)
{
struct xdr_stream xdr;
int status;
xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
status = decode_fhs_status(&xdr, res);
if (unlikely(status != 0 || res->errno != 0))
return status;
status = decode_fhandle3(&xdr, res);
if (unlikely(status != 0)) {
res->errno = -EBADHANDLE;
return 0;
}
return decode_auth_flavors(&xdr, res);
}
static struct rpc_procinfo mnt_procedures[] = {
[MOUNTPROC_MNT] = {
.p_proc = MOUNTPROC_MNT,
.p_encode = (kxdrproc_t)mnt_enc_dirpath,
.p_decode = (kxdrproc_t)mnt_dec_mountres,
.p_arglen = MNT_enc_dirpath_sz,
.p_replen = MNT_dec_mountres_sz,
.p_statidx = MOUNTPROC_MNT,
.p_name = "MOUNT",
},
[MOUNTPROC_UMNT] = {
.p_proc = MOUNTPROC_UMNT,
.p_encode = (kxdrproc_t)mnt_enc_dirpath,
.p_arglen = MNT_enc_dirpath_sz,
.p_statidx = MOUNTPROC_UMNT,
.p_name = "UMOUNT",
},
};
static struct rpc_procinfo mnt3_procedures[] = {
[MOUNTPROC3_MNT] = {
.p_proc = MOUNTPROC3_MNT,
.p_encode = (kxdrproc_t)mnt_enc_dirpath,
.p_decode = (kxdrproc_t)mnt_dec_mountres3,
.p_arglen = MNT_enc_dirpath_sz,
.p_replen = MNT_dec_mountres3_sz,
.p_statidx = MOUNTPROC3_MNT,
.p_name = "MOUNT",
},
[MOUNTPROC3_UMNT] = {
.p_proc = MOUNTPROC3_UMNT,
.p_encode = (kxdrproc_t)mnt_enc_dirpath,
.p_arglen = MNT_enc_dirpath_sz,
.p_statidx = MOUNTPROC3_UMNT,
.p_name = "UMOUNT",
},
};
static struct rpc_version mnt_version1 = {
.number = 1,
.nrprocs = 2,
.procs = mnt_procedures,
};
static struct rpc_version mnt_version3 = {
.number = 3,
.nrprocs = 2,
.procs = mnt3_procedures,
};
static struct rpc_version *mnt_version[] = {
NULL,
&mnt_version1,
NULL,
&mnt_version3,
};
static struct rpc_stat mnt_stats;
static struct rpc_program mnt_program = {
.name = "mount",
.number = NFS_MNT_PROGRAM,
.nrvers = ARRAY_SIZE(mnt_version),
.version = mnt_version,
.stats = &mnt_stats,
};
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