linux/fs/nfs/mount_clnt.c
Scott Mayhew acce94e68a nfsv3: Make v3 mounts fail with ETIMEDOUTs instead EIO on mountd timeouts
In very busy v3 environment, rpc.mountd can respond to the NULL
procedure but not the MNT procedure in a timely manner causing
the MNT procedure to time out. The problem is the mount system
call returns EIO which causes the mount to fail, instead of
ETIMEDOUT, which would cause the mount to be retried.

This patch sets the RPC_TASK_SOFT|RPC_TASK_TIMEOUT flags to
the rpc_call_sync() call in nfs_mount() which causes
ETIMEDOUT to be returned on timed out connections.

Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
2012-10-31 16:26:25 -04:00

519 lines
12 KiB
C

/*
* 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 NFS_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 const 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 = -EREMOTEIO, },
};
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 = {
.net = info->net,
.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, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
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 = {
.net = info->net,
.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 rpc_message msg = {
.rpc_argp = info->dirpath,
};
struct rpc_clnt *clnt;
int status;
if (info->noresvport)
args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
clnt = rpc_create(&args);
if (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 void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
{
const u32 pathname_len = strlen(pathname);
__be32 *p;
BUG_ON(pathname_len > MNTPATHLEN);
p = xdr_reserve_space(xdr, 4 + pathname_len);
xdr_encode_opaque(p, pathname, pathname_len);
}
static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
const char *dirpath)
{
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, 4);
if (unlikely(p == NULL))
return -EIO;
status = be32_to_cpup(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_xdr_dec_mountres(struct rpc_rqst *req,
struct xdr_stream *xdr,
struct mountres *res)
{
int status;
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, 4);
if (unlikely(p == NULL))
return -EIO;
status = be32_to_cpup(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, 4);
if (unlikely(p == NULL))
return -EIO;
size = be32_to_cpup(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, 4);
if (unlikely(p == NULL))
return -EIO;
entries = be32_to_cpup(p);
dprintk("NFS: received %u auth flavors\n", entries);
if (entries > NFS_MAX_SECFLAVORS)
entries = NFS_MAX_SECFLAVORS;
p = xdr_inline_decode(xdr, 4 * entries);
if (unlikely(p == NULL))
return -EIO;
if (entries > *count)
entries = *count;
for (i = 0; i < entries; i++) {
flavors[i] = be32_to_cpup(p++);
dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
}
*count = i;
return 0;
}
static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
struct xdr_stream *xdr,
struct mountres *res)
{
int status;
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 = (kxdreproc_t)mnt_xdr_enc_dirpath,
.p_decode = (kxdrdproc_t)mnt_xdr_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 = (kxdreproc_t)mnt_xdr_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 = (kxdreproc_t)mnt_xdr_enc_dirpath,
.p_decode = (kxdrdproc_t)mnt_xdr_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 = (kxdreproc_t)mnt_xdr_enc_dirpath,
.p_arglen = MNT_enc_dirpath_sz,
.p_statidx = MOUNTPROC3_UMNT,
.p_name = "UMOUNT",
},
};
static const struct rpc_version mnt_version1 = {
.number = 1,
.nrprocs = ARRAY_SIZE(mnt_procedures),
.procs = mnt_procedures,
};
static const struct rpc_version mnt_version3 = {
.number = 3,
.nrprocs = ARRAY_SIZE(mnt3_procedures),
.procs = mnt3_procedures,
};
static const struct rpc_version *mnt_version[] = {
NULL,
&mnt_version1,
NULL,
&mnt_version3,
};
static struct rpc_stat mnt_stats;
static const struct rpc_program mnt_program = {
.name = "mount",
.number = NFS_MNT_PROGRAM,
.nrvers = ARRAY_SIZE(mnt_version),
.version = mnt_version,
.stats = &mnt_stats,
};