v4.19.13 snapshot.
diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
new file mode 100644
index 0000000..a8df2f4
--- /dev/null
+++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
@@ -0,0 +1,666 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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(mirror_ds->ds_versions);
+ 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 = kcalloc(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;
+
+ /*
+ * check for valid major/minor combination.
+ * currently we support dataserver which talk:
+ * v3, v4.0, v4.1, v4.2
+ */
+ if (!((ds_versions[i].version == 3 && ds_versions[i].minor_version == 0) ||
+ (ds_versions[i].version == 4 && ds_versions[i].minor_version < 3))) {
+ 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 (IS_ERR(mirror->mirror_ds))
+ 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;
+}
+
+int
+nfs4_ff_layout_select_ds_stateid(struct pnfs_layout_segment *lseg,
+ u32 mirror_idx,
+ nfs4_stateid *stateid)
+{
+ struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, mirror_idx);
+
+ 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;
+ }
+
+ nfs4_stateid_copy(stateid, &mirror->stateid);
+ return 1;
+out:
+ return 0;
+}
+
+/**
+ * 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;
+ int status;
+
+ 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.
+ */
+ status = 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 (!status) {
+ 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;
+ }
+out_fail:
+ 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);
+ 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.");