| /* |
| * Device operations for the pnfs nfs4 file layout driver. |
| * |
| * Copyright (c) 2014, Primary Data, Inc. All rights reserved. |
| * |
| * Tao Peng <bergwolf@primarydata.com> |
| */ |
| |
| #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 "flexfilelayout.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_PNFS_LD |
| |
| static unsigned int dataserver_timeo = NFS_DEF_TCP_RETRANS; |
| static unsigned int dataserver_retrans; |
| |
| static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg); |
| |
| void nfs4_ff_layout_put_deviceid(struct nfs4_ff_layout_ds *mirror_ds) |
| { |
| if (!IS_ERR_OR_NULL(mirror_ds)) |
| nfs4_put_deviceid_node(&mirror_ds->id_node); |
| } |
| |
| void nfs4_ff_layout_free_deviceid(struct nfs4_ff_layout_ds *mirror_ds) |
| { |
| nfs4_print_deviceid(&mirror_ds->id_node.deviceid); |
| nfs4_pnfs_ds_put(mirror_ds->ds); |
| kfree_rcu(mirror_ds, id_node.rcu); |
| } |
| |
| /* Decode opaque device data and construct new_ds using it */ |
| struct nfs4_ff_layout_ds * |
| nfs4_ff_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev, |
| gfp_t gfp_flags) |
| { |
| struct xdr_stream stream; |
| struct xdr_buf buf; |
| struct page *scratch; |
| struct list_head dsaddrs; |
| struct nfs4_pnfs_ds_addr *da; |
| struct nfs4_ff_layout_ds *new_ds = NULL; |
| struct nfs4_ff_ds_version *ds_versions = NULL; |
| u32 mp_count; |
| u32 version_count; |
| __be32 *p; |
| int i, ret = -ENOMEM; |
| |
| /* set up xdr stream */ |
| scratch = alloc_page(gfp_flags); |
| if (!scratch) |
| goto out_err; |
| |
| new_ds = kzalloc(sizeof(struct nfs4_ff_layout_ds), gfp_flags); |
| if (!new_ds) |
| goto out_scratch; |
| |
| nfs4_init_deviceid_node(&new_ds->id_node, |
| server, |
| &pdev->dev_id); |
| INIT_LIST_HEAD(&dsaddrs); |
| |
| xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen); |
| xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE); |
| |
| /* multipath count */ |
| p = xdr_inline_decode(&stream, 4); |
| if (unlikely(!p)) |
| goto out_err_drain_dsaddrs; |
| mp_count = be32_to_cpup(p); |
| dprintk("%s: multipath ds count %d\n", __func__, mp_count); |
| |
| for (i = 0; i < mp_count; i++) { |
| /* multipath ds */ |
| da = nfs4_decode_mp_ds_addr(server->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__); |
| ret = -ENOMEDIUM; |
| goto out_err_drain_dsaddrs; |
| } |
| |
| /* version count */ |
| p = xdr_inline_decode(&stream, 4); |
| if (unlikely(!p)) |
| goto out_err_drain_dsaddrs; |
| version_count = be32_to_cpup(p); |
| dprintk("%s: version count %d\n", __func__, version_count); |
| |
| ds_versions = kzalloc(version_count * sizeof(struct nfs4_ff_ds_version), |
| gfp_flags); |
| if (!ds_versions) |
| goto out_scratch; |
| |
| for (i = 0; i < version_count; i++) { |
| /* 20 = version(4) + minor_version(4) + rsize(4) + wsize(4) + |
| * tightly_coupled(4) */ |
| p = xdr_inline_decode(&stream, 20); |
| if (unlikely(!p)) |
| goto out_err_drain_dsaddrs; |
| ds_versions[i].version = be32_to_cpup(p++); |
| ds_versions[i].minor_version = be32_to_cpup(p++); |
| ds_versions[i].rsize = nfs_block_size(be32_to_cpup(p++), NULL); |
| ds_versions[i].wsize = nfs_block_size(be32_to_cpup(p++), NULL); |
| ds_versions[i].tightly_coupled = be32_to_cpup(p); |
| |
| if (ds_versions[i].rsize > NFS_MAX_FILE_IO_SIZE) |
| ds_versions[i].rsize = NFS_MAX_FILE_IO_SIZE; |
| if (ds_versions[i].wsize > NFS_MAX_FILE_IO_SIZE) |
| ds_versions[i].wsize = NFS_MAX_FILE_IO_SIZE; |
| |
| if (ds_versions[i].version != 3 || ds_versions[i].minor_version != 0) { |
| dprintk("%s: [%d] unsupported ds version %d-%d\n", __func__, |
| i, ds_versions[i].version, |
| ds_versions[i].minor_version); |
| ret = -EPROTONOSUPPORT; |
| goto out_err_drain_dsaddrs; |
| } |
| |
| dprintk("%s: [%d] vers %u minor_ver %u rsize %u wsize %u coupled %d\n", |
| __func__, i, ds_versions[i].version, |
| ds_versions[i].minor_version, |
| ds_versions[i].rsize, |
| ds_versions[i].wsize, |
| ds_versions[i].tightly_coupled); |
| } |
| |
| new_ds->ds_versions = ds_versions; |
| new_ds->ds_versions_cnt = version_count; |
| |
| new_ds->ds = nfs4_pnfs_ds_add(&dsaddrs, gfp_flags); |
| if (!new_ds->ds) |
| 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 new_ds; |
| |
| 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); |
| } |
| |
| kfree(ds_versions); |
| out_scratch: |
| __free_page(scratch); |
| out_err: |
| kfree(new_ds); |
| |
| dprintk("%s ERROR: returning %d\n", __func__, ret); |
| return NULL; |
| } |
| |
| static void ff_layout_mark_devid_invalid(struct pnfs_layout_segment *lseg, |
| struct nfs4_deviceid_node *devid) |
| { |
| nfs4_delete_deviceid(devid->ld, devid->nfs_client, &devid->deviceid); |
| if (!ff_layout_has_available_ds(lseg)) |
| pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, |
| lseg); |
| } |
| |
| static bool ff_layout_mirror_valid(struct pnfs_layout_segment *lseg, |
| struct nfs4_ff_layout_mirror *mirror, |
| bool create) |
| { |
| if (mirror == NULL || IS_ERR(mirror->mirror_ds)) |
| goto outerr; |
| if (mirror->mirror_ds == NULL) { |
| if (create) { |
| struct nfs4_deviceid_node *node; |
| struct pnfs_layout_hdr *lh = lseg->pls_layout; |
| struct nfs4_ff_layout_ds *mirror_ds = ERR_PTR(-ENODEV); |
| |
| node = nfs4_find_get_deviceid(NFS_SERVER(lh->plh_inode), |
| &mirror->devid, lh->plh_lc_cred, |
| GFP_KERNEL); |
| if (node) |
| mirror_ds = FF_LAYOUT_MIRROR_DS(node); |
| |
| /* check for race with another call to this function */ |
| if (cmpxchg(&mirror->mirror_ds, NULL, mirror_ds) && |
| mirror_ds != ERR_PTR(-ENODEV)) |
| nfs4_put_deviceid_node(node); |
| } else |
| goto outerr; |
| } |
| if (mirror->mirror_ds->ds == NULL) { |
| struct nfs4_deviceid_node *devid; |
| devid = &mirror->mirror_ds->id_node; |
| ff_layout_mark_devid_invalid(lseg, devid); |
| return false; |
| } |
| return true; |
| outerr: |
| pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg); |
| return false; |
| } |
| |
| static void extend_ds_error(struct nfs4_ff_layout_ds_err *err, |
| u64 offset, u64 length) |
| { |
| u64 end; |
| |
| end = max_t(u64, pnfs_end_offset(err->offset, err->length), |
| pnfs_end_offset(offset, length)); |
| err->offset = min_t(u64, err->offset, offset); |
| err->length = end - err->offset; |
| } |
| |
| static int |
| ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1, |
| const struct nfs4_ff_layout_ds_err *e2) |
| { |
| int ret; |
| |
| if (e1->opnum != e2->opnum) |
| return e1->opnum < e2->opnum ? -1 : 1; |
| if (e1->status != e2->status) |
| return e1->status < e2->status ? -1 : 1; |
| ret = memcmp(e1->stateid.data, e2->stateid.data, |
| sizeof(e1->stateid.data)); |
| if (ret != 0) |
| return ret; |
| ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid)); |
| if (ret != 0) |
| return ret; |
| if (pnfs_end_offset(e1->offset, e1->length) < e2->offset) |
| return -1; |
| if (e1->offset > pnfs_end_offset(e2->offset, e2->length)) |
| return 1; |
| /* If ranges overlap or are contiguous, they are the same */ |
| return 0; |
| } |
| |
| static void |
| ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo, |
| struct nfs4_ff_layout_ds_err *dserr) |
| { |
| struct nfs4_ff_layout_ds_err *err, *tmp; |
| struct list_head *head = &flo->error_list; |
| int match; |
| |
| /* Do insertion sort w/ merges */ |
| list_for_each_entry_safe(err, tmp, &flo->error_list, list) { |
| match = ff_ds_error_match(err, dserr); |
| if (match < 0) |
| continue; |
| if (match > 0) { |
| /* Add entry "dserr" _before_ entry "err" */ |
| head = &err->list; |
| break; |
| } |
| /* Entries match, so merge "err" into "dserr" */ |
| extend_ds_error(dserr, err->offset, err->length); |
| list_replace(&err->list, &dserr->list); |
| kfree(err); |
| return; |
| } |
| |
| list_add_tail(&dserr->list, head); |
| } |
| |
| int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo, |
| struct nfs4_ff_layout_mirror *mirror, u64 offset, |
| u64 length, int status, enum nfs_opnum4 opnum, |
| gfp_t gfp_flags) |
| { |
| struct nfs4_ff_layout_ds_err *dserr; |
| |
| if (status == 0) |
| return 0; |
| |
| if (mirror->mirror_ds == NULL) |
| return -EINVAL; |
| |
| dserr = kmalloc(sizeof(*dserr), gfp_flags); |
| if (!dserr) |
| return -ENOMEM; |
| |
| INIT_LIST_HEAD(&dserr->list); |
| dserr->offset = offset; |
| dserr->length = length; |
| dserr->status = status; |
| dserr->opnum = opnum; |
| nfs4_stateid_copy(&dserr->stateid, &mirror->stateid); |
| memcpy(&dserr->deviceid, &mirror->mirror_ds->id_node.deviceid, |
| NFS4_DEVICEID4_SIZE); |
| |
| spin_lock(&flo->generic_hdr.plh_inode->i_lock); |
| ff_layout_add_ds_error_locked(flo, dserr); |
| spin_unlock(&flo->generic_hdr.plh_inode->i_lock); |
| |
| return 0; |
| } |
| |
| static struct rpc_cred * |
| ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode) |
| { |
| struct rpc_cred *cred, __rcu **pcred; |
| |
| if (iomode == IOMODE_READ) |
| pcred = &mirror->ro_cred; |
| else |
| pcred = &mirror->rw_cred; |
| |
| rcu_read_lock(); |
| do { |
| cred = rcu_dereference(*pcred); |
| if (!cred) |
| break; |
| |
| cred = get_rpccred_rcu(cred); |
| } while(!cred); |
| rcu_read_unlock(); |
| return cred; |
| } |
| |
| struct nfs_fh * |
| nfs4_ff_layout_select_ds_fh(struct pnfs_layout_segment *lseg, u32 mirror_idx) |
| { |
| struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, mirror_idx); |
| struct nfs_fh *fh = NULL; |
| |
| if (!ff_layout_mirror_valid(lseg, mirror, false)) { |
| pr_err_ratelimited("NFS: %s: No data server for mirror offset index %d\n", |
| __func__, mirror_idx); |
| goto out; |
| } |
| |
| /* FIXME: For now assume there is only 1 version available for the DS */ |
| fh = &mirror->fh_versions[0]; |
| out: |
| return fh; |
| } |
| |
| /** |
| * nfs4_ff_layout_prepare_ds - prepare a DS connection for an RPC call |
| * @lseg: the layout segment we're operating on |
| * @ds_idx: index of the DS to use |
| * @fail_return: return layout on connect failure? |
| * |
| * Try to prepare a DS connection to accept an RPC call. This involves |
| * selecting a mirror to use and connecting the client to it if it's not |
| * already connected. |
| * |
| * Since we only need a single functioning mirror to satisfy a read, we don't |
| * want to return the layout if there is one. For writes though, any down |
| * mirror should result in a LAYOUTRETURN. @fail_return is how we distinguish |
| * between the two cases. |
| * |
| * Returns a pointer to a connected DS object on success or NULL on failure. |
| */ |
| struct nfs4_pnfs_ds * |
| nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx, |
| bool fail_return) |
| { |
| struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx); |
| struct nfs4_pnfs_ds *ds = NULL; |
| struct nfs4_deviceid_node *devid; |
| struct inode *ino = lseg->pls_layout->plh_inode; |
| struct nfs_server *s = NFS_SERVER(ino); |
| unsigned int max_payload; |
| |
| if (!ff_layout_mirror_valid(lseg, mirror, true)) { |
| pr_err_ratelimited("NFS: %s: No data server for offset index %d\n", |
| __func__, ds_idx); |
| goto out; |
| } |
| |
| devid = &mirror->mirror_ds->id_node; |
| if (ff_layout_test_devid_unavailable(devid)) |
| goto out_fail; |
| |
| ds = mirror->mirror_ds->ds; |
| /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */ |
| smp_rmb(); |
| if (ds->ds_clp) |
| goto out; |
| |
| /* FIXME: For now we assume the server sent only one version of NFS |
| * to use for the DS. |
| */ |
| nfs4_pnfs_ds_connect(s, ds, devid, dataserver_timeo, |
| dataserver_retrans, |
| mirror->mirror_ds->ds_versions[0].version, |
| mirror->mirror_ds->ds_versions[0].minor_version); |
| |
| /* connect success, check rsize/wsize limit */ |
| if (ds->ds_clp) { |
| max_payload = |
| nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient), |
| NULL); |
| if (mirror->mirror_ds->ds_versions[0].rsize > max_payload) |
| mirror->mirror_ds->ds_versions[0].rsize = max_payload; |
| if (mirror->mirror_ds->ds_versions[0].wsize > max_payload) |
| mirror->mirror_ds->ds_versions[0].wsize = max_payload; |
| goto out; |
| } |
| ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout), |
| mirror, lseg->pls_range.offset, |
| lseg->pls_range.length, NFS4ERR_NXIO, |
| OP_ILLEGAL, GFP_NOIO); |
| out_fail: |
| if (fail_return || !ff_layout_has_available_ds(lseg)) |
| pnfs_error_mark_layout_for_return(ino, lseg); |
| ds = NULL; |
| out: |
| return ds; |
| } |
| |
| struct rpc_cred * |
| ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg, u32 ds_idx, |
| struct rpc_cred *mdscred) |
| { |
| struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx); |
| struct rpc_cred *cred; |
| |
| if (mirror) { |
| cred = ff_layout_get_mirror_cred(mirror, lseg->pls_range.iomode); |
| if (!cred) |
| cred = get_rpccred(mdscred); |
| } else { |
| cred = get_rpccred(mdscred); |
| } |
| return cred; |
| } |
| |
| /** |
| * Find or create a DS rpc client with th MDS server rpc client auth flavor |
| * in the nfs_client cl_ds_clients list. |
| */ |
| struct rpc_clnt * |
| nfs4_ff_find_or_create_ds_client(struct pnfs_layout_segment *lseg, u32 ds_idx, |
| struct nfs_client *ds_clp, struct inode *inode) |
| { |
| struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx); |
| |
| switch (mirror->mirror_ds->ds_versions[0].version) { |
| case 3: |
| /* For NFSv3 DS, flavor is set when creating DS connections */ |
| return ds_clp->cl_rpcclient; |
| case 4: |
| return nfs4_find_or_create_ds_client(ds_clp, inode); |
| default: |
| BUG(); |
| } |
| } |
| |
| void ff_layout_free_ds_ioerr(struct list_head *head) |
| { |
| struct nfs4_ff_layout_ds_err *err; |
| |
| while (!list_empty(head)) { |
| err = list_first_entry(head, |
| struct nfs4_ff_layout_ds_err, |
| list); |
| list_del(&err->list); |
| kfree(err); |
| } |
| } |
| |
| /* called with inode i_lock held */ |
| int ff_layout_encode_ds_ioerr(struct xdr_stream *xdr, const struct list_head *head) |
| { |
| struct nfs4_ff_layout_ds_err *err; |
| __be32 *p; |
| |
| list_for_each_entry(err, head, list) { |
| /* offset(8) + length(8) + stateid(NFS4_STATEID_SIZE) |
| * + array length + deviceid(NFS4_DEVICEID4_SIZE) |
| * + status(4) + opnum(4) |
| */ |
| p = xdr_reserve_space(xdr, |
| 28 + NFS4_STATEID_SIZE + NFS4_DEVICEID4_SIZE); |
| if (unlikely(!p)) |
| return -ENOBUFS; |
| p = xdr_encode_hyper(p, err->offset); |
| p = xdr_encode_hyper(p, err->length); |
| p = xdr_encode_opaque_fixed(p, &err->stateid, |
| NFS4_STATEID_SIZE); |
| /* Encode 1 error */ |
| *p++ = cpu_to_be32(1); |
| p = xdr_encode_opaque_fixed(p, &err->deviceid, |
| NFS4_DEVICEID4_SIZE); |
| *p++ = cpu_to_be32(err->status); |
| *p++ = cpu_to_be32(err->opnum); |
| dprintk("%s: offset %llu length %llu status %d op %d\n", |
| __func__, err->offset, err->length, err->status, |
| err->opnum); |
| } |
| |
| return 0; |
| } |
| |
| static |
| unsigned int do_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, |
| const struct pnfs_layout_range *range, |
| struct list_head *head, |
| unsigned int maxnum) |
| { |
| struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo); |
| struct inode *inode = lo->plh_inode; |
| struct nfs4_ff_layout_ds_err *err, *n; |
| unsigned int ret = 0; |
| |
| spin_lock(&inode->i_lock); |
| list_for_each_entry_safe(err, n, &flo->error_list, list) { |
| if (!pnfs_is_range_intersecting(err->offset, |
| pnfs_end_offset(err->offset, err->length), |
| range->offset, |
| pnfs_end_offset(range->offset, range->length))) |
| continue; |
| if (!maxnum) |
| break; |
| list_move(&err->list, head); |
| maxnum--; |
| ret++; |
| } |
| spin_unlock(&inode->i_lock); |
| return ret; |
| } |
| |
| unsigned int ff_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, |
| const struct pnfs_layout_range *range, |
| struct list_head *head, |
| unsigned int maxnum) |
| { |
| unsigned int ret; |
| |
| ret = do_layout_fetch_ds_ioerr(lo, range, head, maxnum); |
| /* If we're over the max, discard all remaining entries */ |
| if (ret == maxnum) { |
| LIST_HEAD(discard); |
| do_layout_fetch_ds_ioerr(lo, range, &discard, -1); |
| ff_layout_free_ds_ioerr(&discard); |
| } |
| return ret; |
| } |
| |
| static bool ff_read_layout_has_available_ds(struct pnfs_layout_segment *lseg) |
| { |
| struct nfs4_ff_layout_mirror *mirror; |
| struct nfs4_deviceid_node *devid; |
| u32 idx; |
| |
| for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { |
| mirror = FF_LAYOUT_COMP(lseg, idx); |
| if (mirror) { |
| if (!mirror->mirror_ds) |
| return true; |
| if (IS_ERR(mirror->mirror_ds)) |
| continue; |
| devid = &mirror->mirror_ds->id_node; |
| if (!ff_layout_test_devid_unavailable(devid)) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static bool ff_rw_layout_has_available_ds(struct pnfs_layout_segment *lseg) |
| { |
| struct nfs4_ff_layout_mirror *mirror; |
| struct nfs4_deviceid_node *devid; |
| u32 idx; |
| |
| for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { |
| mirror = FF_LAYOUT_COMP(lseg, idx); |
| if (!mirror || IS_ERR(mirror->mirror_ds)) |
| return false; |
| if (!mirror->mirror_ds) |
| continue; |
| devid = &mirror->mirror_ds->id_node; |
| if (ff_layout_test_devid_unavailable(devid)) |
| return false; |
| } |
| |
| return FF_LAYOUT_MIRROR_COUNT(lseg) != 0; |
| } |
| |
| static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg) |
| { |
| if (lseg->pls_range.iomode == IOMODE_READ) |
| return ff_read_layout_has_available_ds(lseg); |
| /* Note: RW layout needs all mirrors available */ |
| return ff_rw_layout_has_available_ds(lseg); |
| } |
| |
| bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg) |
| { |
| return ff_layout_no_fallback_to_mds(lseg) || |
| ff_layout_has_available_ds(lseg); |
| } |
| |
| bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg) |
| { |
| return lseg->pls_range.iomode == IOMODE_RW && |
| ff_layout_no_read_on_rw(lseg); |
| } |
| |
| 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."); |