- 根目录:
- fs
- nfs
- nfs4filelayoutdev.c
/*
* Device operations for the pnfs nfs4 file layout driver.
*
* Copyright (c) 2002
* The Regents of the University of Michigan
* All Rights Reserved
*
* Dean Hildebrand <dhildebz@umich.edu>
* Garth Goodson <Garth.Goodson@netapp.com>
*
* Permission is granted to use, copy, create derivative works, and
* redistribute this software and such derivative works for any purpose,
* so long as the name of the University of Michigan is not used in
* any advertising or publicity pertaining to the use or distribution
* of this software without specific, written prior authorization. If
* the above copyright notice or any other identification of the
* University of Michigan is included in any copy of any portion of
* this software, then the disclaimer below must also be included.
*
* This software is provided as is, without representation or warranty
* of any kind either express or implied, including without limitation
* the implied warranties of merchantability, fitness for a particular
* purpose, or noninfringement. The Regents of the University of
* Michigan shall not be liable for any damages, including special,
* indirect, incidental, or consequential damages, with respect to any
* claim arising out of or in connection with the use of the software,
* even if it has been or is hereafter advised of the possibility of
* such damages.
*/
#include <linux/nfs_fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/sunrpc/addr.h>
#include "internal.h"
#include "nfs4session.h"
#include "nfs4filelayout.h"
#define NFSDBG_FACILITY NFSDBG_PNFS_LD
static unsigned int dataserver_timeo = NFS4_DEF_DS_TIMEO;
static unsigned int dataserver_retrans = NFS4_DEF_DS_RETRANS;
/*
* Data server cache
*
* Data servers can be mapped to different device ids.
* nfs4_pnfs_ds reference counting
* - set to 1 on allocation
* - incremented when a device id maps a data server already in the cache.
* - decremented when deviceid is removed from the cache.
*/
static DEFINE_SPINLOCK(nfs4_ds_cache_lock);
static LIST_HEAD(nfs4_data_server_cache);
/* Debug routines */
void
print_ds(struct nfs4_pnfs_ds *ds)
{
if (ds == NULL) {
printk("%s NULL device\n", __func__);
return;
}
printk(" ds %s\n"
" ref count %d\n"
" client %p\n"
" cl_exchange_flags %x\n",
ds->ds_remotestr,
atomic_read(&ds->ds_count), ds->ds_clp,
ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
}
static bool
same_sockaddr(struct sockaddr *addr1, struct sockaddr *addr2)
{
struct sockaddr_in *a, *b;
struct sockaddr_in6 *a6, *b6;
if (addr1->sa_family != addr2->sa_family)
return false;
switch (addr1->sa_family) {
case AF_INET:
a = (struct sockaddr_in *)addr1;
b = (struct sockaddr_in *)addr2;
if (a->sin_addr.s_addr == b->sin_addr.s_addr &&
a->sin_port == b->sin_port)
return true;
break;
case AF_INET6:
a6 = (struct sockaddr_in6 *)addr1;
b6 = (struct sockaddr_in6 *)addr2;
/* LINKLOCAL addresses must have matching scope_id */
if (ipv6_addr_scope(&a6->sin6_addr) ==
IPV6_ADDR_SCOPE_LINKLOCAL &&
a6->sin6_scope_id != b6->sin6_scope_id)
return false;
if (ipv6_addr_equal(&a6->sin6_addr, &b6->sin6_addr) &&
a6->sin6_port == b6->sin6_port)
return true;
break;
default:
dprintk("%s: unhandled address family: %u\n",
__func__, addr1->sa_family);
return false;
}
return false;
}
static bool
_same_data_server_addrs_locked(const struct list_head *dsaddrs1,
const struct list_head *dsaddrs2)
{
struct nfs4_pnfs_ds_addr *da1, *da2;
/* step through both lists, comparing as we go */
for (da1 = list_first_entry(dsaddrs1, typeof(*da1), da_node),
da2 = list_first_entry(dsaddrs2, typeof(*da2), da_node);
da1 != NULL && da2 != NULL;
da1 = list_entry(da1->da_node.next, typeof(*da1), da_node),
da2 = list_entry(da2->da_node.next, typeof(*da2), da_node)) {
if (!same_sockaddr((struct sockaddr *)&da1->da_addr,
(struct sockaddr *)&da2->da_addr))
return false;
}
if (da1 == NULL && da2 == NULL)
return true;
return false;
}
/*
* Lookup DS by addresses. nfs4_ds_cache_lock is held
*/
static struct nfs4_pnfs_ds *
_data_server_lookup_locked(const struct list_head *dsaddrs)
{
struct nfs4_pnfs_ds *ds;
list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
if (_same_data_server_addrs_locked(&ds->ds_addrs, dsaddrs))
return ds;
return NULL;
}
/*
* Create an rpc connection to the nfs4_pnfs_ds data server
* Currently only supports IPv4 and IPv6 addresses
*/
static int
nfs4_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds)
{
struct nfs_client *clp = ERR_PTR(-EIO);
struct nfs4_pnfs_ds_addr *da;
int status = 0;
dprintk("--> %s DS %s au_flavor %d\n", __func__, ds->ds_remotestr,
mds_srv->nfs_client->cl_rpcclient->cl_auth->au_flavor);
list_for_each_entry(da, &ds->ds_addrs, da_node) {
dprintk("%s: DS %s: trying address %s\n",
__func__, ds->ds_remotestr, da->da_remotestr);
clp = nfs4_set_ds_client(mds_srv->nfs_client,
(struct sockaddr *)&da->da_addr,
da->da_addrlen, IPPROTO_TCP,
dataserver_timeo, dataserver_retrans);
if (!IS_ERR(clp))
break;
}
if (IS_ERR(clp)) {
status = PTR_ERR(clp);
goto out;
}
status = nfs4_init_ds_session(clp, mds_srv->nfs_client->cl_lease_time);
if (status)
goto out_put;
ds->ds_clp = clp;
dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
out:
return status;
out_put:
nfs_put_client(clp);
goto out;
}
static void
destroy_ds(struct nfs4_pnfs_ds *ds)
{
struct nfs4_pnfs_ds_addr *da;
dprintk("--> %s\n", __func__);
ifdebug(FACILITY)
print_ds(ds);
if (ds->ds_clp)
nfs_put_client(ds->ds_clp);
while (!list_empty(&ds->ds_addrs)) {
da = list_first_entry(&ds->ds_addrs,
struct nfs4_pnfs_ds_addr,
da_node);
list_del_init(&da->da_node);
kfree(da->da_remotestr);
kfree(da);
}
kfree(ds->ds_remotestr);
kfree(ds);
}
void
nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
{
struct nfs4_pnfs_ds *ds;
int i;
nfs4_print_deviceid(&dsaddr->id_node.deviceid);
for (i = 0; i < dsaddr->ds_num; i++) {
ds = dsaddr->ds_list[i];
if (ds != NULL) {
if (atomic_dec_and_lock(&ds->ds_count,
&nfs4_ds_cache_lock)) {
list_del_init(&ds->ds_node);
spin_unlock(&nfs4_ds_cache_lock);
destroy_ds(ds);
}
}
}
kfree(dsaddr->stripe_indices);
kfree(dsaddr);
}
/*
* Create a string with a human readable address and port to avoid
* complicated setup around many dprinks.
*/
static char *
nfs4_pnfs_remotestr(struct list_head *dsaddrs, gfp_t gfp_flags)
{
struct nfs4_pnfs_ds_addr *da;
char *remotestr;
size_t len;
char *p;
len = 3; /* '{', '}' and eol */
list_for_each_entry(da, dsaddrs, da_node) {
len += strlen(da->da_remotestr) + 1; /* string plus comma */
}
remotestr = kzalloc(len, gfp_flags);
if (!remotestr)
return NULL;
p = remotestr;
*(p++) = '{';
len--;
list_for_each_entry(da, dsaddrs, da_node) {
size_t ll = strlen(da->da_remotestr);
if (ll > len)
goto out_err;
memcpy(p, da->da_remotestr, ll);
p += ll;
len -= ll;
if (len < 1)
goto out_err;
(*p++) = ',';
len--;
}
if (len < 2)
goto out_err;
*(p++) = '}';
*p = '\0';
return remotestr;
out_err:
kfree(remotestr);
return NULL;
}
static struct nfs4_pnfs_ds *
nfs4_pnfs_ds_add(struct list_head *dsaddrs, gfp_t gfp_flags)
{
struct nfs4_pnfs_ds *tmp_ds, *ds = NULL;
char *remotestr;
if (list_empty(dsaddrs)) {
dprintk("%s: no addresses defined\n", __func__);
goto out;
}
ds = kzalloc(sizeof(*ds), gfp_flags);
if (!ds)
goto out;
/* this is only used for debugging, so it's ok if its NULL */
remotestr = nfs4_pnfs_remotestr(dsaddrs, gfp_flags);
spin_lock(&nfs4_ds_cache_lock);
tmp_ds = _data_server_lookup_locked(dsaddrs);
if (tmp_ds == NULL) {
INIT_LIST_HEAD(&ds->ds_addrs);
list_splice_init(dsaddrs, &ds->ds_addrs);
ds->ds_remotestr = remotestr;
atomic_set(&ds->ds_count, 1);
INIT_LIST_HEAD(&ds->ds_node);
ds->ds_clp = NULL;
list_add(&ds->ds_node, &nfs4_data_server_cache);
dprintk("%s add new data server %s\n", __func__,
ds->ds_remotestr);
} else {
kfree(remotestr);
kfree(ds);
atomic_inc(&tmp_ds->ds_count);
dprintk("%s data server %s found, inc'ed ds_count to %d\n",
__func__, tmp_ds->ds_remotestr,
atomic_read(&tmp_ds->ds_count));
ds = tmp_ds;
}
spin_unlock(&nfs4_ds_cache_lock);
out:
return ds;
}
/*
* Currently only supports ipv4, ipv6 and one multi-path address.
*/
static struct nfs4_pnfs_ds_addr *
decode_ds_addr(struct net *net, struct xdr_stream *streamp, gfp_t gfp_flags)
{
struct nfs4_pnfs_ds_addr *da = NULL;
char *buf, *portstr;
__be16 port;
int nlen, rlen;
int tmp[2];
__be32 *p;
char *netid, *match_netid;
size_t len, match_netid_len;
char *startsep = "";
char *endsep = "";
/* r_netid */
p = xdr_inline_decode(streamp, 4);
if (unlikely(!p))
goto out_err;
nlen = be32_to_cpup(p++);
p = xdr_inline_decode(streamp, nlen);
if (unlikely(!p))
goto out_err;
netid = kmalloc(nlen+1, gfp_flags);
if (unlikely(!netid))
goto out_err;
netid[nlen] = '\0';
memcpy(netid, p, nlen);
/* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
p = xdr_inline_decode(streamp, 4);
if (unlikely(!p))
goto out_free_netid;
rlen = be32_to_cpup(p);
p = xdr_inline_decode(streamp, rlen);
if (unlikely(!p))
goto out_free_netid;
/* port is ".ABC.DEF", 8 chars max */
if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
dprintk("%s: Invalid address, length %d\n", __func__,
rlen);
goto out_free_netid;
}
buf = kmalloc(rlen + 1, gfp_flags);
if (!buf) {
dprintk("%s: Not enough memory\n", __func__);
goto out_free_netid;
}
buf[rlen] = '\0';
memcpy(buf, p, rlen);
/* replace port '.' with '-' */
portstr = strrchr(buf, '.');
if (!portstr) {
dprintk("%s: Failed finding expected dot in port\n",
__func__);
goto out_free_buf;
}
*portstr = '-';
/* find '.' between address and port */
portstr = strrchr(buf, '.');
if (!portstr) {
dprintk("%s: Failed finding expected dot between address and "
"port\n", __func__);
goto out_free_buf;
}
*portstr = '\0';
da = kzalloc(sizeof(*da), gfp_flags);
if (unlikely(!da))
goto out_free_buf;
INIT_LIST_HEAD(&da->da_node);
if (!rpc_pton(net, buf, portstr-buf, (struct sockaddr *)&da->da_addr,
sizeof(da->da_addr))) {
dprintk("%s: error parsing address %s\n", __func__, buf);
goto out_free_da;
}
portstr++;
sscanf(portstr, "%d-%d", &tmp[0], &tmp[1]);
port = htons((tmp[0] << 8) | (tmp[1]));
switch (da->da_addr.ss_family) {
case AF_INET:
((struct sockaddr_in *)&da->da_addr)->sin_port = port;
da->da_addrlen = sizeof(struct sockaddr_in);
match_netid = "tcp";
match_netid_len = 3;
break;
case AF_INET6:
((struct sockaddr_in6 *)&da->da_addr)->sin6_port = port;
da->da_addrlen = sizeof(struct sockaddr_in6);
match_netid = "tcp6";
match_netid_len = 4;
startsep = "[";
endsep = "]";
break;
default:
dprintk("%s: unsupported address family: %u\n",
__func__, da->da_addr.ss_family);
goto out_free_da;
}
if (nlen != match_netid_len || strncmp(netid, match_netid, nlen)) {
dprintk("%s: ERROR: r_netid \"%s\" != \"%s\"\n",
__func__, netid, match_netid);
goto out_free_da;
}
/* save human readable address */
len = strlen(startsep) + strlen(buf) + strlen(endsep) + 7;
da->da_remotestr = kzalloc(len, gfp_flags);
/* NULL is ok, only used for dprintk */
if (da->da_remotestr)
snprintf(da->da_remotestr, len, "%s%s%s:%u", startsep,
buf, endsep, ntohs(port));
dprintk("%s: Parsed DS addr %s\n", __func__, da->da_remotestr);
kfree(buf);
kfree(netid);
return da;
out_free_da:
kfree(da);
out_free_buf:
dprintk("%s: Error parsing DS addr: %s\n", __func__, buf);
kfree(buf);
out_free_netid:
kfree(netid);
out_err:
return NULL;
}
/* Decode opaque device data and return the result */
static struct nfs4_file_layout_dsaddr*
decode_device(struct inode *ino, struct pnfs_device *pdev, gfp_t gfp_flags)
{
int i;
u32 cnt, num;
u8 *indexp;
__be32 *p;
u8 *stripe_indices;
u8 max_stripe_index;
struct nfs4_file_layout_dsaddr *dsaddr = NULL;
struct xdr_stream stream;
struct xdr_buf buf;
struct page *scratch;
struct list_head dsaddrs;
struct nfs4_pnfs_ds_addr *da;
/* set up xdr stream */
scratch = alloc_page(gfp_flags);
if (!scratch)
goto out_err;
xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
/* Get the stripe count (number of stripe index) */
p = xdr_inline_decode(&stream, 4);
if (unlikely(!p))
goto out_err_free_scratch;
cnt = be32_to_cpup(p);
dprintk("%s stripe count %d\n", __func__, cnt);
if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
printk(KERN_WARNING "NFS: %s: stripe count %d greater than "
"supported maximum %d\n", __func__,
cnt, NFS4_PNFS_MAX_STRIPE_CNT);
goto out_err_free_scratch;
}
/* read stripe indices */
stripe_indices = kcalloc(cnt, sizeof(u8), gfp_flags);
if (!stripe_indices)
goto out_err_free_scratch;
p = xdr_inline_decode(&stream, cnt << 2);
if (unlikely(!p))
goto out_err_free_stripe_indices;
indexp = &stripe_indices[0];
max_stripe_index = 0;
for (i = 0; i < cnt; i++) {
*indexp = be32_to_cpup(p++);
max_stripe_index = max(max_stripe_index, *indexp);
indexp++;
}
/* Check the multipath list count */
p = xdr_inline_decode(&stream, 4);
if (unlikely(!p))
goto out_err_free_stripe_indices;
num = be32_to_cpup(p);
dprintk("%s ds_num %u\n", __func__, num);
if (num > NFS4_PNFS_MAX_MULTI_CNT) {
printk(KERN_WARNING "NFS: %s: multipath count %d greater than "
"supported maximum %d\n", __func__,
num, NFS4_PNFS_MAX_MULTI_CNT);
goto out_err_free_stripe_indices;
}
/* validate stripe indices are all < num */
if (max_stripe_index >= num) {
printk(KERN_WARNING "NFS: %s: stripe index %u >= num ds %u\n",
__func__, max_stripe_index, num);
goto out_err_free_stripe_indices;
}
dsaddr = kzalloc(sizeof(*dsaddr) +
(sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
gfp_flags);
if (!dsaddr)
goto out_err_free_stripe_indices;
dsaddr->stripe_count = cnt;
dsaddr->stripe_indices = stripe_indices;
stripe_indices = NULL;
dsaddr->ds_num = num;
nfs4_init_deviceid_node(&dsaddr->id_node,
NFS_SERVER(ino)->pnfs_curr_ld,
NFS_SERVER(ino)->nfs_client,
&pdev->dev_id);
INIT_LIST_HEAD(&dsaddrs);
for (i = 0; i < dsaddr->ds_num; i++) {
int j;
u32 mp_count;
p = xdr_inline_decode(&stream, 4);
if (unlikely(!p))
goto out_err_free_deviceid;
mp_count = be32_to_cpup(p); /* multipath count */
for (j = 0; j < mp_count; j++) {
da = decode_ds_addr(NFS_SERVER(ino)->nfs_client->cl_net,
&stream, gfp_flags);
if (da)
list_add_tail(&da->da_node, &dsaddrs);
}
if (list_empty(&dsaddrs)) {
dprintk("%s: no suitable DS addresses found\n",
__func__);
goto out_err_free_deviceid;
}
dsaddr->ds_list[i] = nfs4_pnfs_ds_add(&dsaddrs, gfp_flags);
if (!dsaddr->ds_list[i])
goto out_err_drain_dsaddrs;
/* If DS was already in cache, free ds addrs */
while (!list_empty(&dsaddrs)) {
da = list_first_entry(&dsaddrs,
struct nfs4_pnfs_ds_addr,
da_node);
list_del_init(&da->da_node);
kfree(da->da_remotestr);
kfree(da);
}
}
__free_page(scratch);
return dsaddr;
out_err_drain_dsaddrs:
while (!list_empty(&dsaddrs)) {
da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr,
da_node);
list_del_init(&da->da_node);
kfree(da->da_remotestr);
kfree(da);
}
out_err_free_deviceid:
nfs4_fl_free_deviceid(dsaddr);
/* stripe_indicies was part of dsaddr */
goto out_err_free_scratch;
out_err_free_stripe_indices:
kfree(stripe_indices);
out_err_free_scratch:
__free_page(scratch);
out_err:
dprintk("%s ERROR: returning NULL\n", __func__);
return NULL;
}
/*
* Decode the opaque device specified in 'dev' and add it to the cache of
* available devices.
*/
static struct nfs4_file_layout_dsaddr *
decode_and_add_device(struct inode *inode, struct pnfs_device *dev, gfp_t gfp_flags)
{
struct nfs4_deviceid_node *d;
struct nfs4_file_layout_dsaddr *n, *new;
new = decode_device(inode, dev, gfp_flags);
if (!new) {
printk(KERN_WARNING "NFS: %s: Could not decode or add device\n",
__func__);
return NULL;
}
d = nfs4_insert_deviceid_node(&new->id_node);
n = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
if (n != new) {
nfs4_fl_free_deviceid(new);
return n;
}
return new;
}
/*
* Retrieve the information for dev_id, add it to the list
* of available devices, and return it.
*/
struct nfs4_file_layout_dsaddr *
filelayout_get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags)
{
struct pnfs_device *pdev = NULL;
u32 max_resp_sz;
int max_pages;
struct page **pages = NULL;
struct nfs4_file_layout_dsaddr *dsaddr = NULL;
int rc, i;
struct nfs_server *server = NFS_SERVER(inode);
/*
* Use the session max response size as the basis for setting
* GETDEVICEINFO's maxcount
*/
max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
max_pages = nfs_page_array_len(0, max_resp_sz);
dprintk("%s inode %p max_resp_sz %u max_pages %d\n",
__func__, inode, max_resp_sz, max_pages);
pdev = kzalloc(sizeof(struct pnfs_device), gfp_flags);
if (pdev == NULL)
return NULL;
pages = kzalloc(max_pages * sizeof(struct page *), gfp_flags);
if (pages == NULL) {
kfree(pdev);
return NULL;
}
for (i = 0; i < max_pages; i++) {
pages[i] = alloc_page(gfp_flags);
if (!pages[i])
goto out_free;
}
memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
pdev->layout_type = LAYOUT_NFSV4_1_FILES;
pdev->pages = pages;
pdev->pgbase = 0;
pdev->pglen = max_resp_sz;
pdev->mincount = 0;
rc = nfs4_proc_getdeviceinfo(server, pdev);
dprintk("%s getdevice info returns %d\n", __func__, rc);
if (rc)
goto out_free;
/*
* Found new device, need to decode it and then add it to the
* list of known devices for this mountpoint.
*/
dsaddr = decode_and_add_device(inode, pdev, gfp_flags);
out_free:
for (i = 0; i < max_pages; i++)
__free_page(pages[i]);
kfree(pages);
kfree(pdev);
dprintk("<-- %s dsaddr %p\n", __func__, dsaddr);
return dsaddr;
}
void
nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
{
nfs4_put_deviceid_node(&dsaddr->id_node);
}
/*
* Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
* Then: ((res + fsi) % dsaddr->stripe_count)
*/
u32
nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
{
struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
u64 tmp;
tmp = offset - flseg->pattern_offset;
do_div(tmp, flseg->stripe_unit);
tmp += flseg->first_stripe_index;
return do_div(tmp, flseg->dsaddr->stripe_count);
}
u32
nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
{
return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
}
struct nfs_fh *
nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
{
struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
u32 i;
if (flseg->stripe_type == STRIPE_SPARSE) {
if (flseg->num_fh == 1)
i = 0;
else if (flseg->num_fh == 0)
/* Use the MDS OPEN fh set in nfs_read_rpcsetup */
return NULL;
else
i = nfs4_fl_calc_ds_index(lseg, j);
} else
i = j;
return flseg->fh_array[i];
}
static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
{
might_sleep();
wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING,
nfs_wait_bit_killable, TASK_KILLABLE);
}
static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
{
smp_mb__before_clear_bit();
clear_bit(NFS4DS_CONNECTING, &ds->ds_state);
smp_mb__after_clear_bit();
wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING);
}
struct nfs4_pnfs_ds *
nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
{
struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
struct nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
if (filelayout_test_devid_unavailable(devid))
return NULL;
if (ds == NULL) {
printk(KERN_ERR "NFS: %s: No data server for offset index %d\n",
__func__, ds_idx);
filelayout_mark_devid_invalid(devid);
return NULL;
}
if (ds->ds_clp)
return ds;
if (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) == 0) {
struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
int err;
err = nfs4_ds_connect(s, ds);
if (err) {
nfs4_mark_deviceid_unavailable(devid);
ds = NULL;
}
nfs4_clear_ds_conn_bit(ds);
} else {
/* Either ds is connected, or ds is NULL */
nfs4_wait_ds_connect(ds);
}
return ds;
}
module_param(dataserver_retrans, uint, 0644);
MODULE_PARM_DESC(dataserver_retrans, "The number of times the NFSv4.1 client "
"retries a request before it attempts further "
" recovery action.");
module_param(dataserver_timeo, uint, 0644);
MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the "
"NFSv4.1 client waits for a response from a "
" data server before it retries an NFS request.");