fs/nfs/filelayout/filelayout.c

   1 /*
   2  *  Module for the pnfs nfs4 file layout driver.
   3  *  Defines all I/O and Policy interface operations, plus code
   4  *  to register itself with the pNFS client.
   5  *
   6  *  Copyright (c) 2002
   7  *  The Regents of the University of Michigan
   8  *  All Rights Reserved
   9  *
  10  *  Dean Hildebrand <dhildebz@umich.edu>
  11  *
  12  *  Permission is granted to use, copy, create derivative works, and
  13  *  redistribute this software and such derivative works for any purpose,
  14  *  so long as the name of the University of Michigan is not used in
  15  *  any advertising or publicity pertaining to the use or distribution
  16  *  of this software without specific, written prior authorization. If
  17  *  the above copyright notice or any other identification of the
  18  *  University of Michigan is included in any copy of any portion of
  19  *  this software, then the disclaimer below must also be included.
  20  *
  21  *  This software is provided as is, without representation or warranty
  22  *  of any kind either express or implied, including without limitation
  23  *  the implied warranties of merchantability, fitness for a particular
  24  *  purpose, or noninfringement.  The Regents of the University of
  25  *  Michigan shall not be liable for any damages, including special,
  26  *  indirect, incidental, or consequential damages, with respect to any
  27  *  claim arising out of or in connection with the use of the software,
  28  *  even if it has been or is hereafter advised of the possibility of
  29  *  such damages.
  30  */
  31
  32 #include <linux/nfs_fs.h>
  33 #include <linux/nfs_page.h>
  34 #include <linux/module.h>
  35 #include <linux/backing-dev.h>
  36
  37 #include <linux/sunrpc/metrics.h>
  38
  39 #include "../nfs4session.h"
  40 #include "../internal.h"
  41 #include "../delegation.h"
  42 #include "filelayout.h"
  43 #include "../nfs4trace.h"
  44
  45 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  46
  47 MODULE_LICENSE("GPL");
  48 MODULE_AUTHOR("Dean Hildebrand <dhildebz@umich.edu>");
  49 MODULE_DESCRIPTION("The NFSv4 file layout driver");
  50
  51 #define FILELAYOUT_POLL_RETRY_MAX     (15*HZ)
  52
  53 static loff_t
  54 filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg,
  55                             loff_t offset)
  56 {
  57         u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count;
  58         u64 stripe_no;
  59         u32 rem;
  60
  61         offset -= flseg->pattern_offset;
  62         stripe_no = div_u64(offset, stripe_width);
  63         div_u64_rem(offset, flseg->stripe_unit, &rem);
  64
  65         return stripe_no * flseg->stripe_unit + rem;
  66 }
  67
  68 /* This function is used by the layout driver to calculate the
  69  * offset of the file on the dserver based on whether the
  70  * layout type is STRIPE_DENSE or STRIPE_SPARSE
  71  */
  72 static loff_t
  73 filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset)
  74 {
  75         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
  76
  77         switch (flseg->stripe_type) {
  78         case STRIPE_SPARSE:
  79                 return offset;
  80
  81         case STRIPE_DENSE:
  82                 return filelayout_get_dense_offset(flseg, offset);
  83         }
  84
  85         BUG();
  86 }
  87
  88 static void filelayout_reset_write(struct nfs_pgio_header *hdr)
  89 {
  90         struct rpc_task *task = &hdr->task;
  91
  92         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
  93                 dprintk("%s Reset task %5u for i/o through MDS "
  94                         "(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
  95                         hdr->task.tk_pid,
  96                         hdr->inode->i_sb->s_id,
  97                         (unsigned long long)NFS_FILEID(hdr->inode),
  98                         hdr->args.count,
  99                         (unsigned long long)hdr->args.offset);
 100
 101                 task->tk_status = pnfs_write_done_resend_to_mds(hdr);
 102         }
 103 }
 104
 105 static void filelayout_reset_read(struct nfs_pgio_header *hdr)
 106 {
 107         struct rpc_task *task = &hdr->task;
 108
 109         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
 110                 dprintk("%s Reset task %5u for i/o through MDS "
 111                         "(req %s/%llu, %u bytes @ offset %llu)\n", __func__,
 112                         hdr->task.tk_pid,
 113                         hdr->inode->i_sb->s_id,
 114                         (unsigned long long)NFS_FILEID(hdr->inode),
 115                         hdr->args.count,
 116                         (unsigned long long)hdr->args.offset);
 117
 118                 task->tk_status = pnfs_read_done_resend_to_mds(hdr);
 119         }
 120 }
 121
 122 static int filelayout_async_handle_error(struct rpc_task *task,
 123                                          struct nfs4_state *state,
 124                                          struct nfs_client *clp,
 125                                          struct pnfs_layout_segment *lseg)
 126 {
 127         struct pnfs_layout_hdr *lo = lseg->pls_layout;
 128         struct inode *inode = lo->plh_inode;
 129         struct nfs_server *mds_server = NFS_SERVER(inode);
 130         struct nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
 131         struct nfs_client *mds_client = mds_server->nfs_client;
 132         struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
 133
 134         if (task->tk_status >= 0)
 135                 return 0;
 136
 137         switch (task->tk_status) {
 138         /* MDS state errors */
 139         case -NFS4ERR_DELEG_REVOKED:
 140         case -NFS4ERR_ADMIN_REVOKED:
 141         case -NFS4ERR_BAD_STATEID:
 142         case -NFS4ERR_OPENMODE:
 143                 if (state == NULL)
 144                         break;
 145                 if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
 146                         goto out_bad_stateid;
 147                 goto wait_on_recovery;
 148         case -NFS4ERR_EXPIRED:
 149                 if (state != NULL) {
 150                         if (nfs4_schedule_stateid_recovery(mds_server, state) < 0)
 151                                 goto out_bad_stateid;
 152                 }
 153                 nfs4_schedule_lease_recovery(mds_client);
 154                 goto wait_on_recovery;
 155         /* DS session errors */
 156         case -NFS4ERR_BADSESSION:
 157         case -NFS4ERR_BADSLOT:
 158         case -NFS4ERR_BAD_HIGH_SLOT:
 159         case -NFS4ERR_DEADSESSION:
 160         case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
 161         case -NFS4ERR_SEQ_FALSE_RETRY:
 162         case -NFS4ERR_SEQ_MISORDERED:
 163                 dprintk("%s ERROR %d, Reset session. Exchangeid "
 164                         "flags 0x%x\n", __func__, task->tk_status,
 165                         clp->cl_exchange_flags);
 166                 nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
 167                 break;
 168         case -NFS4ERR_DELAY:
 169         case -NFS4ERR_GRACE:
 170                 rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
 171                 break;
 172         case -NFS4ERR_RETRY_UNCACHED_REP:
 173                 break;
 174         /* Invalidate Layout errors */
 175         case -NFS4ERR_PNFS_NO_LAYOUT:
 176         case -ESTALE:           /* mapped NFS4ERR_STALE */
 177         case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
 178         case -EISDIR:           /* mapped NFS4ERR_ISDIR */
 179         case -NFS4ERR_FHEXPIRED:
 180         case -NFS4ERR_WRONG_TYPE:
 181                 dprintk("%s Invalid layout error %d\n", __func__,
 182                         task->tk_status);
 183                 /*
 184                  * Destroy layout so new i/o will get a new layout.
 185                  * Layout will not be destroyed until all current lseg
 186                  * references are put. Mark layout as invalid to resend failed
 187                  * i/o and all i/o waiting on the slot table to the MDS until
 188                  * layout is destroyed and a new valid layout is obtained.
 189                  */
 190                 pnfs_destroy_layout(NFS_I(inode));
 191                 rpc_wake_up(&tbl->slot_tbl_waitq);
 192                 goto reset;
 193         /* RPC connection errors */
 194         case -ECONNREFUSED:
 195         case -EHOSTDOWN:
 196         case -EHOSTUNREACH:
 197         case -ENETUNREACH:
 198         case -EIO:
 199         case -ETIMEDOUT:
 200         case -EPIPE:
 201                 dprintk("%s DS connection error %d\n", __func__,
 202                         task->tk_status);
 203                 nfs4_mark_deviceid_unavailable(devid);
 204                 pnfs_error_mark_layout_for_return(inode, lseg);
 205                 pnfs_set_lo_fail(lseg);
 206                 rpc_wake_up(&tbl->slot_tbl_waitq);
 207                 /* fall through */
 208         default:
 209 reset:
 210                 dprintk("%s Retry through MDS. Error %d\n", __func__,
 211                         task->tk_status);
 212                 return -NFS4ERR_RESET_TO_MDS;
 213         }
 214 out:
 215         task->tk_status = 0;
 216         return -EAGAIN;
 217 out_bad_stateid:
 218         task->tk_status = -EIO;
 219         return 0;
 220 wait_on_recovery:
 221         rpc_sleep_on(&mds_client->cl_rpcwaitq, task, NULL);
 222         if (test_bit(NFS4CLNT_MANAGER_RUNNING, &mds_client->cl_state) == 0)
 223                 rpc_wake_up_queued_task(&mds_client->cl_rpcwaitq, task);
 224         goto out;
 225 }
 226
 227 /* NFS_PROTO call done callback routines */
 228
 229 static int filelayout_read_done_cb(struct rpc_task *task,
 230                                 struct nfs_pgio_header *hdr)
 231 {
 232         int err;
 233
 234         trace_nfs4_pnfs_read(hdr, task->tk_status);
 235         err = filelayout_async_handle_error(task, hdr->args.context->state,
 236                                             hdr->ds_clp, hdr->lseg);
 237
 238         switch (err) {
 239         case -NFS4ERR_RESET_TO_MDS:
 240                 filelayout_reset_read(hdr);
 241                 return task->tk_status;
 242         case -EAGAIN:
 243                 rpc_restart_call_prepare(task);
 244                 return -EAGAIN;
 245         }
 246
 247         return 0;
 248 }
 249
 250 /*
 251  * We reference the rpc_cred of the first WRITE that triggers the need for
 252  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
 253  * rfc5661 is not clear about which credential should be used.
 254  */
 255 static void
 256 filelayout_set_layoutcommit(struct nfs_pgio_header *hdr)
 257 {
 258         loff_t end_offs = 0;
 259
 260         if (FILELAYOUT_LSEG(hdr->lseg)->commit_through_mds ||
 261             hdr->res.verf->committed == NFS_FILE_SYNC)
 262                 return;
 263         if (hdr->res.verf->committed == NFS_DATA_SYNC)
 264                 end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
 265
 266         /* Note: if the write is unstable, don't set end_offs until commit */
 267         pnfs_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
 268         dprintk("%s inode %lu pls_end_pos %lu\n", __func__, hdr->inode->i_ino,
 269                 (unsigned long) NFS_I(hdr->inode)->layout->plh_lwb);
 270 }
 271
 272 bool
 273 filelayout_test_devid_unavailable(struct nfs4_deviceid_node *node)
 274 {
 275         return filelayout_test_devid_invalid(node) ||
 276                 nfs4_test_deviceid_unavailable(node);
 277 }
 278
 279 static bool
 280 filelayout_reset_to_mds(struct pnfs_layout_segment *lseg)
 281 {
 282         struct nfs4_deviceid_node *node = FILELAYOUT_DEVID_NODE(lseg);
 283
 284         return filelayout_test_devid_unavailable(node);
 285 }
 286
 287 /*
 288  * Call ops for the async read/write cases
 289  * In the case of dense layouts, the offset needs to be reset to its
 290  * original value.
 291  */
 292 static void filelayout_read_prepare(struct rpc_task *task, void *data)
 293 {
 294         struct nfs_pgio_header *hdr = data;
 295
 296         if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 297                 rpc_exit(task, -EIO);
 298                 return;
 299         }
 300         if (filelayout_reset_to_mds(hdr->lseg)) {
 301                 dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
 302                 filelayout_reset_read(hdr);
 303                 rpc_exit(task, 0);
 304                 return;
 305         }
 306         hdr->pgio_done_cb = filelayout_read_done_cb;
 307
 308         if (nfs4_setup_sequence(hdr->ds_clp,
 309                         &hdr->args.seq_args,
 310                         &hdr->res.seq_res,
 311                         task))
 312                 return;
 313         if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 314                         hdr->args.lock_context, FMODE_READ) == -EIO)
 315                 rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 316 }
 317
 318 static void filelayout_read_call_done(struct rpc_task *task, void *data)
 319 {
 320         struct nfs_pgio_header *hdr = data;
 321
 322         dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
 323
 324         if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 325             task->tk_status == 0) {
 326                 nfs41_sequence_done(task, &hdr->res.seq_res);
 327                 return;
 328         }
 329
 330         /* Note this may cause RPC to be resent */
 331         hdr->mds_ops->rpc_call_done(task, data);
 332 }
 333
 334 static void filelayout_read_count_stats(struct rpc_task *task, void *data)
 335 {
 336         struct nfs_pgio_header *hdr = data;
 337
 338         rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
 339 }
 340
 341 static int filelayout_write_done_cb(struct rpc_task *task,
 342                                 struct nfs_pgio_header *hdr)
 343 {
 344         int err;
 345
 346         trace_nfs4_pnfs_write(hdr, task->tk_status);
 347         err = filelayout_async_handle_error(task, hdr->args.context->state,
 348                                             hdr->ds_clp, hdr->lseg);
 349
 350         switch (err) {
 351         case -NFS4ERR_RESET_TO_MDS:
 352                 filelayout_reset_write(hdr);
 353                 return task->tk_status;
 354         case -EAGAIN:
 355                 rpc_restart_call_prepare(task);
 356                 return -EAGAIN;
 357         }
 358
 359         filelayout_set_layoutcommit(hdr);
 360
 361         /* zero out the fattr */
 362         hdr->fattr.valid = 0;
 363         if (task->tk_status >= 0)
 364                 nfs_writeback_update_inode(hdr);
 365
 366         return 0;
 367 }
 368
 369 static int filelayout_commit_done_cb(struct rpc_task *task,
 370                                      struct nfs_commit_data *data)
 371 {
 372         int err;
 373
 374         trace_nfs4_pnfs_commit_ds(data, task->tk_status);
 375         err = filelayout_async_handle_error(task, NULL, data->ds_clp,
 376                                             data->lseg);
 377
 378         switch (err) {
 379         case -NFS4ERR_RESET_TO_MDS:
 380                 pnfs_generic_prepare_to_resend_writes(data);
 381                 return -EAGAIN;
 382         case -EAGAIN:
 383                 rpc_restart_call_prepare(task);
 384                 return -EAGAIN;
 385         }
 386
 387         pnfs_set_layoutcommit(data->inode, data->lseg, data->lwb);
 388
 389         return 0;
 390 }
 391
 392 static void filelayout_write_prepare(struct rpc_task *task, void *data)
 393 {
 394         struct nfs_pgio_header *hdr = data;
 395
 396         if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 397                 rpc_exit(task, -EIO);
 398                 return;
 399         }
 400         if (filelayout_reset_to_mds(hdr->lseg)) {
 401                 dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
 402                 filelayout_reset_write(hdr);
 403                 rpc_exit(task, 0);
 404                 return;
 405         }
 406         if (nfs4_setup_sequence(hdr->ds_clp,
 407                         &hdr->args.seq_args,
 408                         &hdr->res.seq_res,
 409                         task))
 410                 return;
 411         if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 412                         hdr->args.lock_context, FMODE_WRITE) == -EIO)
 413                 rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 414 }
 415
 416 static void filelayout_write_call_done(struct rpc_task *task, void *data)
 417 {
 418         struct nfs_pgio_header *hdr = data;
 419
 420         if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 421             task->tk_status == 0) {
 422                 nfs41_sequence_done(task, &hdr->res.seq_res);
 423                 return;
 424         }
 425
 426         /* Note this may cause RPC to be resent */
 427         hdr->mds_ops->rpc_call_done(task, data);
 428 }
 429
 430 static void filelayout_write_count_stats(struct rpc_task *task, void *data)
 431 {
 432         struct nfs_pgio_header *hdr = data;
 433
 434         rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
 435 }
 436
 437 static void filelayout_commit_prepare(struct rpc_task *task, void *data)
 438 {
 439         struct nfs_commit_data *wdata = data;
 440
 441         nfs4_setup_sequence(wdata->ds_clp,
 442                         &wdata->args.seq_args,
 443                         &wdata->res.seq_res,
 444                         task);
 445 }
 446
 447 static void filelayout_commit_count_stats(struct rpc_task *task, void *data)
 448 {
 449         struct nfs_commit_data *cdata = data;
 450
 451         rpc_count_iostats(task, NFS_SERVER(cdata->inode)->client->cl_metrics);
 452 }
 453
 454 static const struct rpc_call_ops filelayout_read_call_ops = {
 455         .rpc_call_prepare = filelayout_read_prepare,
 456         .rpc_call_done = filelayout_read_call_done,
 457         .rpc_count_stats = filelayout_read_count_stats,
 458         .rpc_release = pnfs_generic_rw_release,
 459 };
 460
 461 static const struct rpc_call_ops filelayout_write_call_ops = {
 462         .rpc_call_prepare = filelayout_write_prepare,
 463         .rpc_call_done = filelayout_write_call_done,
 464         .rpc_count_stats = filelayout_write_count_stats,
 465         .rpc_release = pnfs_generic_rw_release,
 466 };
 467
 468 static const struct rpc_call_ops filelayout_commit_call_ops = {
 469         .rpc_call_prepare = filelayout_commit_prepare,
 470         .rpc_call_done = pnfs_generic_write_commit_done,
 471         .rpc_count_stats = filelayout_commit_count_stats,
 472         .rpc_release = pnfs_generic_commit_release,
 473 };
 474
 475 static enum pnfs_try_status
 476 filelayout_read_pagelist(struct nfs_pgio_header *hdr)
 477 {
 478         struct pnfs_layout_segment *lseg = hdr->lseg;
 479         struct nfs4_pnfs_ds *ds;
 480         struct rpc_clnt *ds_clnt;
 481         loff_t offset = hdr->args.offset;
 482         u32 j, idx;
 483         struct nfs_fh *fh;
 484
 485         dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
 486                 __func__, hdr->inode->i_ino,
 487                 hdr->args.pgbase, (size_t)hdr->args.count, offset);
 488
 489         /* Retrieve the correct rpc_client for the byte range */
 490         j = nfs4_fl_calc_j_index(lseg, offset);
 491         idx = nfs4_fl_calc_ds_index(lseg, j);
 492         ds = nfs4_fl_prepare_ds(lseg, idx);
 493         if (!ds)
 494                 return PNFS_NOT_ATTEMPTED;
 495
 496         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, hdr->inode);
 497         if (IS_ERR(ds_clnt))
 498                 return PNFS_NOT_ATTEMPTED;
 499
 500         dprintk("%s USE DS: %s cl_count %d\n", __func__,
 501                 ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count));
 502
 503         /* No multipath support. Use first DS */
 504         atomic_inc(&ds->ds_clp->cl_count);
 505         hdr->ds_clp = ds->ds_clp;
 506         hdr->ds_commit_idx = idx;
 507         fh = nfs4_fl_select_ds_fh(lseg, j);
 508         if (fh)
 509                 hdr->args.fh = fh;
 510
 511         hdr->args.offset = filelayout_get_dserver_offset(lseg, offset);
 512         hdr->mds_offset = offset;
 513
 514         /* Perform an asynchronous read to ds */
 515         nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
 516                           NFS_PROTO(hdr->inode), &filelayout_read_call_ops,
 517                           0, RPC_TASK_SOFTCONN);
 518         return PNFS_ATTEMPTED;
 519 }
 520
 521 /* Perform async writes. */
 522 static enum pnfs_try_status
 523 filelayout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 524 {
 525         struct pnfs_layout_segment *lseg = hdr->lseg;
 526         struct nfs4_pnfs_ds *ds;
 527         struct rpc_clnt *ds_clnt;
 528         loff_t offset = hdr->args.offset;
 529         u32 j, idx;
 530         struct nfs_fh *fh;
 531
 532         /* Retrieve the correct rpc_client for the byte range */
 533         j = nfs4_fl_calc_j_index(lseg, offset);
 534         idx = nfs4_fl_calc_ds_index(lseg, j);
 535         ds = nfs4_fl_prepare_ds(lseg, idx);
 536         if (!ds)
 537                 return PNFS_NOT_ATTEMPTED;
 538
 539         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, hdr->inode);
 540         if (IS_ERR(ds_clnt))
 541                 return PNFS_NOT_ATTEMPTED;
 542
 543         dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d\n",
 544                 __func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
 545                 offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count));
 546
 547         hdr->pgio_done_cb = filelayout_write_done_cb;
 548         atomic_inc(&ds->ds_clp->cl_count);
 549         hdr->ds_clp = ds->ds_clp;
 550         hdr->ds_commit_idx = idx;
 551         fh = nfs4_fl_select_ds_fh(lseg, j);
 552         if (fh)
 553                 hdr->args.fh = fh;
 554         hdr->args.offset = filelayout_get_dserver_offset(lseg, offset);
 555
 556         /* Perform an asynchronous write */
 557         nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
 558                           NFS_PROTO(hdr->inode), &filelayout_write_call_ops,
 559                           sync, RPC_TASK_SOFTCONN);
 560         return PNFS_ATTEMPTED;
 561 }
 562
 563 /*
 564  * filelayout_check_layout()
 565  *
 566  * Make sure layout segment parameters are sane WRT the device.
 567  * At this point no generic layer initialization of the lseg has occurred,
 568  * and nothing has been added to the layout_hdr cache.
 569  *
 570  */
 571 static int
 572 filelayout_check_layout(struct pnfs_layout_hdr *lo,
 573                         struct nfs4_filelayout_segment *fl,
 574                         struct nfs4_layoutget_res *lgr,
 575                         struct nfs4_deviceid *id,
 576                         gfp_t gfp_flags)
 577 {
 578         struct nfs4_deviceid_node *d;
 579         struct nfs4_file_layout_dsaddr *dsaddr;
 580         int status = -EINVAL;
 581
 582         dprintk("--> %s\n", __func__);
 583
 584         /* FIXME: remove this check when layout segment support is added */
 585         if (lgr->range.offset != 0 ||
 586             lgr->range.length != NFS4_MAX_UINT64) {
 587                 dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
 588                         __func__);
 589                 goto out;
 590         }
 591
 592         if (fl->pattern_offset > lgr->range.offset) {
 593                 dprintk("%s pattern_offset %lld too large\n",
 594                                 __func__, fl->pattern_offset);
 595                 goto out;
 596         }
 597
 598         if (!fl->stripe_unit) {
 599                 dprintk("%s Invalid stripe unit (%u)\n",
 600                         __func__, fl->stripe_unit);
 601                 goto out;
 602         }
 603
 604         /* find and reference the deviceid */
 605         d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), id,
 606                         lo->plh_lc_cred, gfp_flags);
 607         if (d == NULL)
 608                 goto out;
 609
 610         dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
 611         /* Found deviceid is unavailable */
 612         if (filelayout_test_devid_unavailable(&dsaddr->id_node))
 613                 goto out_put;
 614
 615         fl->dsaddr = dsaddr;
 616
 617         if (fl->first_stripe_index >= dsaddr->stripe_count) {
 618                 dprintk("%s Bad first_stripe_index %u\n",
 619                                 __func__, fl->first_stripe_index);
 620                 goto out_put;
 621         }
 622
 623         if ((fl->stripe_type == STRIPE_SPARSE &&
 624             fl->num_fh > 1 && fl->num_fh != dsaddr->ds_num) ||
 625             (fl->stripe_type == STRIPE_DENSE &&
 626             fl->num_fh != dsaddr->stripe_count)) {
 627                 dprintk("%s num_fh %u not valid for given packing\n",
 628                         __func__, fl->num_fh);
 629                 goto out_put;
 630         }
 631
 632         status = 0;
 633 out:
 634         dprintk("--> %s returns %d\n", __func__, status);
 635         return status;
 636 out_put:
 637         nfs4_fl_put_deviceid(dsaddr);
 638         goto out;
 639 }
 640
 641 static void _filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
 642 {
 643         int i;
 644
 645         if (fl->fh_array) {
 646                 for (i = 0; i < fl->num_fh; i++) {
 647                         if (!fl->fh_array[i])
 648                                 break;
 649                         kfree(fl->fh_array[i]);
 650                 }
 651                 kfree(fl->fh_array);
 652         }
 653         kfree(fl);
 654 }
 655
 656 static int
 657 filelayout_decode_layout(struct pnfs_layout_hdr *flo,
 658                          struct nfs4_filelayout_segment *fl,
 659                          struct nfs4_layoutget_res *lgr,
 660                          struct nfs4_deviceid *id,
 661                          gfp_t gfp_flags)
 662 {
 663         struct xdr_stream stream;
 664         struct xdr_buf buf;
 665         struct page *scratch;
 666         __be32 *p;
 667         uint32_t nfl_util;
 668         int i;
 669
 670         dprintk("%s: set_layout_map Begin\n", __func__);
 671
 672         scratch = alloc_page(gfp_flags);
 673         if (!scratch)
 674                 return -ENOMEM;
 675
 676         xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
 677         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 678
 679         /* 20 = ufl_util (4), first_stripe_index (4), pattern_offset (8),
 680          * num_fh (4) */
 681         p = xdr_inline_decode(&stream, NFS4_DEVICEID4_SIZE + 20);
 682         if (unlikely(!p))
 683                 goto out_err;
 684
 685         memcpy(id, p, sizeof(*id));
 686         p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
 687         nfs4_print_deviceid(id);
 688
 689         nfl_util = be32_to_cpup(p++);
 690         if (nfl_util & NFL4_UFLG_COMMIT_THRU_MDS)
 691                 fl->commit_through_mds = 1;
 692         if (nfl_util & NFL4_UFLG_DENSE)
 693                 fl->stripe_type = STRIPE_DENSE;
 694         else
 695                 fl->stripe_type = STRIPE_SPARSE;
 696         fl->stripe_unit = nfl_util & ~NFL4_UFLG_MASK;
 697
 698         fl->first_stripe_index = be32_to_cpup(p++);
 699         p = xdr_decode_hyper(p, &fl->pattern_offset);
 700         fl->num_fh = be32_to_cpup(p++);
 701
 702         dprintk("%s: nfl_util 0x%X num_fh %u fsi %u po %llu\n",
 703                 __func__, nfl_util, fl->num_fh, fl->first_stripe_index,
 704                 fl->pattern_offset);
 705
 706         /* Note that a zero value for num_fh is legal for STRIPE_SPARSE.
 707          * Futher checking is done in filelayout_check_layout */
 708         if (fl->num_fh >
 709             max(NFS4_PNFS_MAX_STRIPE_CNT, NFS4_PNFS_MAX_MULTI_CNT))
 710                 goto out_err;
 711
 712         if (fl->num_fh > 0) {
 713                 fl->fh_array = kcalloc(fl->num_fh, sizeof(fl->fh_array[0]),
 714                                        gfp_flags);
 715                 if (!fl->fh_array)
 716                         goto out_err;
 717         }
 718
 719         for (i = 0; i < fl->num_fh; i++) {
 720                 /* Do we want to use a mempool here? */
 721                 fl->fh_array[i] = kmalloc(sizeof(struct nfs_fh), gfp_flags);
 722                 if (!fl->fh_array[i])
 723                         goto out_err;
 724
 725                 p = xdr_inline_decode(&stream, 4);
 726                 if (unlikely(!p))
 727                         goto out_err;
 728                 fl->fh_array[i]->size = be32_to_cpup(p++);
 729                 if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
 730                         printk(KERN_ERR "NFS: Too big fh %d received %d\n",
 731                                i, fl->fh_array[i]->size);
 732                         goto out_err;
 733                 }
 734
 735                 p = xdr_inline_decode(&stream, fl->fh_array[i]->size);
 736                 if (unlikely(!p))
 737                         goto out_err;
 738                 memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
 739                 dprintk("DEBUG: %s: fh len %d\n", __func__,
 740                         fl->fh_array[i]->size);
 741         }
 742
 743         __free_page(scratch);
 744         return 0;
 745
 746 out_err:
 747         __free_page(scratch);
 748         return -EIO;
 749 }
 750
 751 static void
 752 filelayout_free_lseg(struct pnfs_layout_segment *lseg)
 753 {
 754         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 755
 756         dprintk("--> %s\n", __func__);
 757         nfs4_fl_put_deviceid(fl->dsaddr);
 758         /* This assumes a single RW lseg */
 759         if (lseg->pls_range.iomode == IOMODE_RW) {
 760                 struct nfs4_filelayout *flo;
 761
 762                 flo = FILELAYOUT_FROM_HDR(lseg->pls_layout);
 763                 flo->commit_info.nbuckets = 0;
 764                 kfree(flo->commit_info.buckets);
 765                 flo->commit_info.buckets = NULL;
 766         }
 767         _filelayout_free_lseg(fl);
 768 }
 769
 770 static int
 771 filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
 772                              struct nfs_commit_info *cinfo,
 773                              gfp_t gfp_flags)
 774 {
 775         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 776         struct pnfs_commit_bucket *buckets;
 777         int size, i;
 778
 779         if (fl->commit_through_mds)
 780                 return 0;
 781
 782         size = (fl->stripe_type == STRIPE_SPARSE) ?
 783                 fl->dsaddr->ds_num : fl->dsaddr->stripe_count;
 784
 785         if (cinfo->ds->nbuckets >= size) {
 786                 /* This assumes there is only one IOMODE_RW lseg.  What
 787                  * we really want to do is have a layout_hdr level
 788                  * dictionary of <multipath_list4, fh> keys, each
 789                  * associated with a struct list_head, populated by calls
 790                  * to filelayout_write_pagelist().
 791                  * */
 792                 return 0;
 793         }
 794
 795         buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
 796                           gfp_flags);
 797         if (!buckets)
 798                 return -ENOMEM;
 799         for (i = 0; i < size; i++) {
 800                 INIT_LIST_HEAD(&buckets[i].written);
 801                 INIT_LIST_HEAD(&buckets[i].committing);
 802                 /* mark direct verifier as unset */
 803                 buckets[i].direct_verf.committed = NFS_INVALID_STABLE_HOW;
 804         }
 805
 806         spin_lock(&cinfo->inode->i_lock);
 807         if (cinfo->ds->nbuckets >= size)
 808                 goto out;
 809         for (i = 0; i < cinfo->ds->nbuckets; i++) {
 810                 list_splice(&cinfo->ds->buckets[i].written,
 811                             &buckets[i].written);
 812                 list_splice(&cinfo->ds->buckets[i].committing,
 813                             &buckets[i].committing);
 814                 buckets[i].direct_verf.committed =
 815                         cinfo->ds->buckets[i].direct_verf.committed;
 816                 buckets[i].wlseg = cinfo->ds->buckets[i].wlseg;
 817                 buckets[i].clseg = cinfo->ds->buckets[i].clseg;
 818         }
 819         swap(cinfo->ds->buckets, buckets);
 820         cinfo->ds->nbuckets = size;
 821 out:
 822         spin_unlock(&cinfo->inode->i_lock);
 823         kfree(buckets);
 824         return 0;
 825 }
 826
 827 static struct pnfs_layout_segment *
 828 filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
 829                       struct nfs4_layoutget_res *lgr,
 830                       gfp_t gfp_flags)
 831 {
 832         struct nfs4_filelayout_segment *fl;
 833         int rc;
 834         struct nfs4_deviceid id;
 835
 836         dprintk("--> %s\n", __func__);
 837         fl = kzalloc(sizeof(*fl), gfp_flags);
 838         if (!fl)
 839                 return NULL;
 840
 841         rc = filelayout_decode_layout(layoutid, fl, lgr, &id, gfp_flags);
 842         if (rc != 0 || filelayout_check_layout(layoutid, fl, lgr, &id, gfp_flags)) {
 843                 _filelayout_free_lseg(fl);
 844                 return NULL;
 845         }
 846         return &fl->generic_hdr;
 847 }
 848
 849 /*
 850  * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
 851  *
 852  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
 853  * of bytes (maximum @req->wb_bytes) that can be coalesced.
 854  */
 855 static size_t
 856 filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 857                    struct nfs_page *req)
 858 {
 859         unsigned int size;
 860         u64 p_stripe, r_stripe;
 861         u32 stripe_offset;
 862         u64 segment_offset = pgio->pg_lseg->pls_range.offset;
 863         u32 stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
 864
 865         /* calls nfs_generic_pg_test */
 866         size = pnfs_generic_pg_test(pgio, prev, req);
 867         if (!size)
 868                 return 0;
 869
 870         /* see if req and prev are in the same stripe */
 871         if (prev) {
 872                 p_stripe = (u64)req_offset(prev) - segment_offset;
 873                 r_stripe = (u64)req_offset(req) - segment_offset;
 874                 do_div(p_stripe, stripe_unit);
 875                 do_div(r_stripe, stripe_unit);
 876
 877                 if (p_stripe != r_stripe)
 878                         return 0;
 879         }
 880
 881         /* calculate remaining bytes in the current stripe */
 882         div_u64_rem((u64)req_offset(req) - segment_offset,
 883                         stripe_unit,
 884                         &stripe_offset);
 885         WARN_ON_ONCE(stripe_offset > stripe_unit);
 886         if (stripe_offset >= stripe_unit)
 887                 return 0;
 888         return min(stripe_unit - (unsigned int)stripe_offset, size);
 889 }
 890
 891 static void
 892 filelayout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 893                         struct nfs_page *req)
 894 {
 895         if (!pgio->pg_lseg) {
 896                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 897                                            req->wb_context,
 898                                            0,
 899                                            NFS4_MAX_UINT64,
 900                                            IOMODE_READ,
 901                                            false,
 902                                            GFP_KERNEL);
 903                 if (IS_ERR(pgio->pg_lseg)) {
 904                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
 905                         pgio->pg_lseg = NULL;
 906                         return;
 907                 }
 908         }
 909         /* If no lseg, fall back to read through mds */
 910         if (pgio->pg_lseg == NULL)
 911                 nfs_pageio_reset_read_mds(pgio);
 912 }
 913
 914 static void
 915 filelayout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 916                          struct nfs_page *req)
 917 {
 918         struct nfs_commit_info cinfo;
 919         int status;
 920
 921         if (!pgio->pg_lseg) {
 922                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
 923                                            req->wb_context,
 924                                            0,
 925                                            NFS4_MAX_UINT64,
 926                                            IOMODE_RW,
 927                                            false,
 928                                            GFP_NOFS);
 929                 if (IS_ERR(pgio->pg_lseg)) {
 930                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
 931                         pgio->pg_lseg = NULL;
 932                         return;
 933                 }
 934         }
 935
 936         /* If no lseg, fall back to write through mds */
 937         if (pgio->pg_lseg == NULL)
 938                 goto out_mds;
 939         nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
 940         status = filelayout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
 941         if (status < 0) {
 942                 pnfs_put_lseg(pgio->pg_lseg);
 943                 pgio->pg_lseg = NULL;
 944                 goto out_mds;
 945         }
 946         return;
 947 out_mds:
 948         nfs_pageio_reset_write_mds(pgio);
 949 }
 950
 951 static const struct nfs_pageio_ops filelayout_pg_read_ops = {
 952         .pg_init = filelayout_pg_init_read,
 953         .pg_test = filelayout_pg_test,
 954         .pg_doio = pnfs_generic_pg_readpages,
 955         .pg_cleanup = pnfs_generic_pg_cleanup,
 956 };
 957
 958 static const struct nfs_pageio_ops filelayout_pg_write_ops = {
 959         .pg_init = filelayout_pg_init_write,
 960         .pg_test = filelayout_pg_test,
 961         .pg_doio = pnfs_generic_pg_writepages,
 962         .pg_cleanup = pnfs_generic_pg_cleanup,
 963 };
 964
 965 static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
 966 {
 967         if (fl->stripe_type == STRIPE_SPARSE)
 968                 return nfs4_fl_calc_ds_index(&fl->generic_hdr, j);
 969         else
 970                 return j;
 971 }
 972
 973 static void
 974 filelayout_mark_request_commit(struct nfs_page *req,
 975                                struct pnfs_layout_segment *lseg,
 976                                struct nfs_commit_info *cinfo,
 977                                u32 ds_commit_idx)
 978
 979 {
 980         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 981         u32 i, j;
 982
 983         if (fl->commit_through_mds) {
 984                 nfs_request_add_commit_list(req, cinfo);
 985         } else {
 986                 /* Note that we are calling nfs4_fl_calc_j_index on each page
 987                  * that ends up being committed to a data server.  An attractive
 988                  * alternative is to add a field to nfs_write_data and nfs_page
 989                  * to store the value calculated in filelayout_write_pagelist
 990                  * and just use that here.
 991                  */
 992                 j = nfs4_fl_calc_j_index(lseg, req_offset(req));
 993                 i = select_bucket_index(fl, j);
 994                 pnfs_layout_mark_request_commit(req, lseg, cinfo, i);
 995         }
 996 }
 997
 998 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
 999 {
1000         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
1001
1002         if (flseg->stripe_type == STRIPE_SPARSE)
1003                 return i;
1004         else
1005                 return nfs4_fl_calc_ds_index(lseg, i);
1006 }
1007
1008 static struct nfs_fh *
1009 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1010 {
1011         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
1012
1013         if (flseg->stripe_type == STRIPE_SPARSE) {
1014                 if (flseg->num_fh == 1)
1015                         i = 0;
1016                 else if (flseg->num_fh == 0)
1017                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
1018                         return NULL;
1019         }
1020         return flseg->fh_array[i];
1021 }
1022
1023 static int filelayout_initiate_commit(struct nfs_commit_data *data, int how)
1024 {
1025         struct pnfs_layout_segment *lseg = data->lseg;
1026         struct nfs4_pnfs_ds *ds;
1027         struct rpc_clnt *ds_clnt;
1028         u32 idx;
1029         struct nfs_fh *fh;
1030
1031         idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1032         ds = nfs4_fl_prepare_ds(lseg, idx);
1033         if (!ds)
1034                 goto out_err;
1035
1036         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, data->inode);
1037         if (IS_ERR(ds_clnt))
1038                 goto out_err;
1039
1040         dprintk("%s ino %lu, how %d cl_count %d\n", __func__,
1041                 data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count));
1042         data->commit_done_cb = filelayout_commit_done_cb;
1043         atomic_inc(&ds->ds_clp->cl_count);
1044         data->ds_clp = ds->ds_clp;
1045         fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1046         if (fh)
1047                 data->args.fh = fh;
1048         return nfs_initiate_commit(ds_clnt, data, NFS_PROTO(data->inode),
1049                                    &filelayout_commit_call_ops, how,
1050                                    RPC_TASK_SOFTCONN);
1051 out_err:
1052         pnfs_generic_prepare_to_resend_writes(data);
1053         pnfs_generic_commit_release(data);
1054         return -EAGAIN;
1055 }
1056
1057 /* filelayout_search_commit_reqs - Search lists in @cinfo for the head reqest
1058  *                                 for @page
1059  * @cinfo - commit info for current inode
1060  * @page - page to search for matching head request
1061  *
1062  * Returns a the head request if one is found, otherwise returns NULL.
1063  */
1064 static struct nfs_page *
1065 filelayout_search_commit_reqs(struct nfs_commit_info *cinfo, struct page *page)
1066 {
1067         struct nfs_page *freq, *t;
1068         struct pnfs_commit_bucket *b;
1069         int i;
1070
1071         /* Linearly search the commit lists for each bucket until a matching
1072          * request is found */
1073         for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
1074                 list_for_each_entry_safe(freq, t, &b->written, wb_list) {
1075                         if (freq->wb_page == page)
1076                                 return freq->wb_head;
1077                 }
1078                 list_for_each_entry_safe(freq, t, &b->committing, wb_list) {
1079                         if (freq->wb_page == page)
1080                                 return freq->wb_head;
1081                 }
1082         }
1083
1084         return NULL;
1085 }
1086
1087 static int
1088 filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1089                            int how, struct nfs_commit_info *cinfo)
1090 {
1091         return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1092                                             filelayout_initiate_commit);
1093 }
1094
1095 static struct nfs4_deviceid_node *
1096 filelayout_alloc_deviceid_node(struct nfs_server *server,
1097                 struct pnfs_device *pdev, gfp_t gfp_flags)
1098 {
1099         struct nfs4_file_layout_dsaddr *dsaddr;
1100
1101         dsaddr = nfs4_fl_alloc_deviceid_node(server, pdev, gfp_flags);
1102         if (!dsaddr)
1103                 return NULL;
1104         return &dsaddr->id_node;
1105 }
1106
1107 static void
1108 filelayout_free_deviceid_node(struct nfs4_deviceid_node *d)
1109 {
1110         nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
1111 }
1112
1113 static struct pnfs_layout_hdr *
1114 filelayout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
1115 {
1116         struct nfs4_filelayout *flo;
1117
1118         flo = kzalloc(sizeof(*flo), gfp_flags);
1119         return flo != NULL ? &flo->generic_hdr : NULL;
1120 }
1121
1122 static void
1123 filelayout_free_layout_hdr(struct pnfs_layout_hdr *lo)
1124 {
1125         kfree(FILELAYOUT_FROM_HDR(lo));
1126 }
1127
1128 static struct pnfs_ds_commit_info *
1129 filelayout_get_ds_info(struct inode *inode)
1130 {
1131         struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1132
1133         if (layout == NULL)
1134                 return NULL;
1135         else
1136                 return &FILELAYOUT_FROM_HDR(layout)->commit_info;
1137 }
1138
1139 static struct pnfs_layoutdriver_type filelayout_type = {
1140         .id                     = LAYOUT_NFSV4_1_FILES,
1141         .name                   = "LAYOUT_NFSV4_1_FILES",
1142         .owner                  = THIS_MODULE,
1143         .alloc_layout_hdr       = filelayout_alloc_layout_hdr,
1144         .free_layout_hdr        = filelayout_free_layout_hdr,
1145         .alloc_lseg             = filelayout_alloc_lseg,
1146         .free_lseg              = filelayout_free_lseg,
1147         .pg_read_ops            = &filelayout_pg_read_ops,
1148         .pg_write_ops           = &filelayout_pg_write_ops,
1149         .get_ds_info            = &filelayout_get_ds_info,
1150         .mark_request_commit    = filelayout_mark_request_commit,
1151         .clear_request_commit   = pnfs_generic_clear_request_commit,
1152         .scan_commit_lists      = pnfs_generic_scan_commit_lists,
1153         .recover_commit_reqs    = pnfs_generic_recover_commit_reqs,
1154         .search_commit_reqs     = filelayout_search_commit_reqs,
1155         .commit_pagelist        = filelayout_commit_pagelist,
1156         .read_pagelist          = filelayout_read_pagelist,
1157         .write_pagelist         = filelayout_write_pagelist,
1158         .alloc_deviceid_node    = filelayout_alloc_deviceid_node,
1159         .free_deviceid_node     = filelayout_free_deviceid_node,
1160         .sync                   = pnfs_nfs_generic_sync,
1161 };
1162
1163 static int __init nfs4filelayout_init(void)
1164 {
1165         printk(KERN_INFO "%s: NFSv4 File Layout Driver Registering...\n",
1166                __func__);
1167         return pnfs_register_layoutdriver(&filelayout_type);
1168 }
1169
1170 static void __exit nfs4filelayout_exit(void)
1171 {
1172         printk(KERN_INFO "%s: NFSv4 File Layout Driver Unregistering...\n",
1173                __func__);
1174         pnfs_unregister_layoutdriver(&filelayout_type);
1175 }
1176
1177 MODULE_ALIAS("nfs-layouttype4-1");
1178
1179 module_init(nfs4filelayout_init);
1180 module_exit(nfs4filelayout_exit);