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 nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
 130         struct nfs4_slot_table *tbl = &clp->cl_session->fc_slot_table;
 131
 132         if (task->tk_status >= 0)
 133                 return 0;
 134
 135         switch (task->tk_status) {
 136         /* DS session errors */
 137         case -NFS4ERR_BADSESSION:
 138         case -NFS4ERR_BADSLOT:
 139         case -NFS4ERR_BAD_HIGH_SLOT:
 140         case -NFS4ERR_DEADSESSION:
 141         case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
 142         case -NFS4ERR_SEQ_FALSE_RETRY:
 143         case -NFS4ERR_SEQ_MISORDERED:
 144                 dprintk("%s ERROR %d, Reset session. Exchangeid "
 145                         "flags 0x%x\n", __func__, task->tk_status,
 146                         clp->cl_exchange_flags);
 147                 nfs4_schedule_session_recovery(clp->cl_session, task->tk_status);
 148                 break;
 149         case -NFS4ERR_DELAY:
 150         case -NFS4ERR_GRACE:
 151                 rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
 152                 break;
 153         case -NFS4ERR_RETRY_UNCACHED_REP:
 154                 break;
 155         /* Invalidate Layout errors */
 156         case -NFS4ERR_ACCESS:
 157         case -NFS4ERR_PNFS_NO_LAYOUT:
 158         case -ESTALE:           /* mapped NFS4ERR_STALE */
 159         case -EBADHANDLE:       /* mapped NFS4ERR_BADHANDLE */
 160         case -EISDIR:           /* mapped NFS4ERR_ISDIR */
 161         case -NFS4ERR_FHEXPIRED:
 162         case -NFS4ERR_WRONG_TYPE:
 163                 dprintk("%s Invalid layout error %d\n", __func__,
 164                         task->tk_status);
 165                 /*
 166                  * Destroy layout so new i/o will get a new layout.
 167                  * Layout will not be destroyed until all current lseg
 168                  * references are put. Mark layout as invalid to resend failed
 169                  * i/o and all i/o waiting on the slot table to the MDS until
 170                  * layout is destroyed and a new valid layout is obtained.
 171                  */
 172                 pnfs_destroy_layout(NFS_I(inode));
 173                 rpc_wake_up(&tbl->slot_tbl_waitq);
 174                 goto reset;
 175         /* RPC connection errors */
 176         case -ECONNREFUSED:
 177         case -EHOSTDOWN:
 178         case -EHOSTUNREACH:
 179         case -ENETUNREACH:
 180         case -EIO:
 181         case -ETIMEDOUT:
 182         case -EPIPE:
 183                 dprintk("%s DS connection error %d\n", __func__,
 184                         task->tk_status);
 185                 nfs4_mark_deviceid_unavailable(devid);
 186                 pnfs_error_mark_layout_for_return(inode, lseg);
 187                 pnfs_set_lo_fail(lseg);
 188                 rpc_wake_up(&tbl->slot_tbl_waitq);
 189                 /* fall through */
 190         default:
 191 reset:
 192                 dprintk("%s Retry through MDS. Error %d\n", __func__,
 193                         task->tk_status);
 194                 return -NFS4ERR_RESET_TO_MDS;
 195         }
 196         task->tk_status = 0;
 197         return -EAGAIN;
 198 }
 199
 200 /* NFS_PROTO call done callback routines */
 201
 202 static int filelayout_read_done_cb(struct rpc_task *task,
 203                                 struct nfs_pgio_header *hdr)
 204 {
 205         int err;
 206
 207         trace_nfs4_pnfs_read(hdr, task->tk_status);
 208         err = filelayout_async_handle_error(task, hdr->args.context->state,
 209                                             hdr->ds_clp, hdr->lseg);
 210
 211         switch (err) {
 212         case -NFS4ERR_RESET_TO_MDS:
 213                 filelayout_reset_read(hdr);
 214                 return task->tk_status;
 215         case -EAGAIN:
 216                 rpc_restart_call_prepare(task);
 217                 return -EAGAIN;
 218         }
 219
 220         return 0;
 221 }
 222
 223 /*
 224  * We reference the rpc_cred of the first WRITE that triggers the need for
 225  * a LAYOUTCOMMIT, and use it to send the layoutcommit compound.
 226  * rfc5661 is not clear about which credential should be used.
 227  */
 228 static void
 229 filelayout_set_layoutcommit(struct nfs_pgio_header *hdr)
 230 {
 231         loff_t end_offs = 0;
 232
 233         if (FILELAYOUT_LSEG(hdr->lseg)->commit_through_mds ||
 234             hdr->res.verf->committed == NFS_FILE_SYNC)
 235                 return;
 236         if (hdr->res.verf->committed == NFS_DATA_SYNC)
 237                 end_offs = hdr->mds_offset + (loff_t)hdr->res.count;
 238
 239         /* Note: if the write is unstable, don't set end_offs until commit */
 240         pnfs_set_layoutcommit(hdr->inode, hdr->lseg, end_offs);
 241         dprintk("%s inode %lu pls_end_pos %lu\n", __func__, hdr->inode->i_ino,
 242                 (unsigned long) NFS_I(hdr->inode)->layout->plh_lwb);
 243 }
 244
 245 bool
 246 filelayout_test_devid_unavailable(struct nfs4_deviceid_node *node)
 247 {
 248         return filelayout_test_devid_invalid(node) ||
 249                 nfs4_test_deviceid_unavailable(node);
 250 }
 251
 252 static bool
 253 filelayout_reset_to_mds(struct pnfs_layout_segment *lseg)
 254 {
 255         struct nfs4_deviceid_node *node = FILELAYOUT_DEVID_NODE(lseg);
 256
 257         return filelayout_test_devid_unavailable(node);
 258 }
 259
 260 /*
 261  * Call ops for the async read/write cases
 262  * In the case of dense layouts, the offset needs to be reset to its
 263  * original value.
 264  */
 265 static void filelayout_read_prepare(struct rpc_task *task, void *data)
 266 {
 267         struct nfs_pgio_header *hdr = data;
 268
 269         if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 270                 rpc_exit(task, -EIO);
 271                 return;
 272         }
 273         if (filelayout_reset_to_mds(hdr->lseg)) {
 274                 dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
 275                 filelayout_reset_read(hdr);
 276                 rpc_exit(task, 0);
 277                 return;
 278         }
 279         hdr->pgio_done_cb = filelayout_read_done_cb;
 280
 281         if (nfs4_setup_sequence(hdr->ds_clp,
 282                         &hdr->args.seq_args,
 283                         &hdr->res.seq_res,
 284                         task))
 285                 return;
 286         if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 287                         hdr->args.lock_context, FMODE_READ) == -EIO)
 288                 rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 289 }
 290
 291 static void filelayout_read_call_done(struct rpc_task *task, void *data)
 292 {
 293         struct nfs_pgio_header *hdr = data;
 294
 295         dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
 296
 297         if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 298             task->tk_status == 0) {
 299                 nfs41_sequence_done(task, &hdr->res.seq_res);
 300                 return;
 301         }
 302
 303         /* Note this may cause RPC to be resent */
 304         hdr->mds_ops->rpc_call_done(task, data);
 305 }
 306
 307 static void filelayout_read_count_stats(struct rpc_task *task, void *data)
 308 {
 309         struct nfs_pgio_header *hdr = data;
 310
 311         rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
 312 }
 313
 314 static int filelayout_write_done_cb(struct rpc_task *task,
 315                                 struct nfs_pgio_header *hdr)
 316 {
 317         int err;
 318
 319         trace_nfs4_pnfs_write(hdr, task->tk_status);
 320         err = filelayout_async_handle_error(task, hdr->args.context->state,
 321                                             hdr->ds_clp, hdr->lseg);
 322
 323         switch (err) {
 324         case -NFS4ERR_RESET_TO_MDS:
 325                 filelayout_reset_write(hdr);
 326                 return task->tk_status;
 327         case -EAGAIN:
 328                 rpc_restart_call_prepare(task);
 329                 return -EAGAIN;
 330         }
 331
 332         filelayout_set_layoutcommit(hdr);
 333
 334         /* zero out the fattr */
 335         hdr->fattr.valid = 0;
 336         if (task->tk_status >= 0)
 337                 nfs_writeback_update_inode(hdr);
 338
 339         return 0;
 340 }
 341
 342 static int filelayout_commit_done_cb(struct rpc_task *task,
 343                                      struct nfs_commit_data *data)
 344 {
 345         int err;
 346
 347         trace_nfs4_pnfs_commit_ds(data, task->tk_status);
 348         err = filelayout_async_handle_error(task, NULL, data->ds_clp,
 349                                             data->lseg);
 350
 351         switch (err) {
 352         case -NFS4ERR_RESET_TO_MDS:
 353                 pnfs_generic_prepare_to_resend_writes(data);
 354                 return -EAGAIN;
 355         case -EAGAIN:
 356                 rpc_restart_call_prepare(task);
 357                 return -EAGAIN;
 358         }
 359
 360         pnfs_set_layoutcommit(data->inode, data->lseg, data->lwb);
 361
 362         return 0;
 363 }
 364
 365 static void filelayout_write_prepare(struct rpc_task *task, void *data)
 366 {
 367         struct nfs_pgio_header *hdr = data;
 368
 369         if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags))) {
 370                 rpc_exit(task, -EIO);
 371                 return;
 372         }
 373         if (filelayout_reset_to_mds(hdr->lseg)) {
 374                 dprintk("%s task %u reset io to MDS\n", __func__, task->tk_pid);
 375                 filelayout_reset_write(hdr);
 376                 rpc_exit(task, 0);
 377                 return;
 378         }
 379         if (nfs4_setup_sequence(hdr->ds_clp,
 380                         &hdr->args.seq_args,
 381                         &hdr->res.seq_res,
 382                         task))
 383                 return;
 384         if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
 385                         hdr->args.lock_context, FMODE_WRITE) == -EIO)
 386                 rpc_exit(task, -EIO); /* lost lock, terminate I/O */
 387 }
 388
 389 static void filelayout_write_call_done(struct rpc_task *task, void *data)
 390 {
 391         struct nfs_pgio_header *hdr = data;
 392
 393         if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 394             task->tk_status == 0) {
 395                 nfs41_sequence_done(task, &hdr->res.seq_res);
 396                 return;
 397         }
 398
 399         /* Note this may cause RPC to be resent */
 400         hdr->mds_ops->rpc_call_done(task, data);
 401 }
 402
 403 static void filelayout_write_count_stats(struct rpc_task *task, void *data)
 404 {
 405         struct nfs_pgio_header *hdr = data;
 406
 407         rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
 408 }
 409
 410 static void filelayout_commit_prepare(struct rpc_task *task, void *data)
 411 {
 412         struct nfs_commit_data *wdata = data;
 413
 414         nfs4_setup_sequence(wdata->ds_clp,
 415                         &wdata->args.seq_args,
 416                         &wdata->res.seq_res,
 417                         task);
 418 }
 419
 420 static void filelayout_commit_count_stats(struct rpc_task *task, void *data)
 421 {
 422         struct nfs_commit_data *cdata = data;
 423
 424         rpc_count_iostats(task, NFS_SERVER(cdata->inode)->client->cl_metrics);
 425 }
 426
 427 static const struct rpc_call_ops filelayout_read_call_ops = {
 428         .rpc_call_prepare = filelayout_read_prepare,
 429         .rpc_call_done = filelayout_read_call_done,
 430         .rpc_count_stats = filelayout_read_count_stats,
 431         .rpc_release = pnfs_generic_rw_release,
 432 };
 433
 434 static const struct rpc_call_ops filelayout_write_call_ops = {
 435         .rpc_call_prepare = filelayout_write_prepare,
 436         .rpc_call_done = filelayout_write_call_done,
 437         .rpc_count_stats = filelayout_write_count_stats,
 438         .rpc_release = pnfs_generic_rw_release,
 439 };
 440
 441 static const struct rpc_call_ops filelayout_commit_call_ops = {
 442         .rpc_call_prepare = filelayout_commit_prepare,
 443         .rpc_call_done = pnfs_generic_write_commit_done,
 444         .rpc_count_stats = filelayout_commit_count_stats,
 445         .rpc_release = pnfs_generic_commit_release,
 446 };
 447
 448 static enum pnfs_try_status
 449 filelayout_read_pagelist(struct nfs_pgio_header *hdr)
 450 {
 451         struct pnfs_layout_segment *lseg = hdr->lseg;
 452         struct nfs4_pnfs_ds *ds;
 453         struct rpc_clnt *ds_clnt;
 454         loff_t offset = hdr->args.offset;
 455         u32 j, idx;
 456         struct nfs_fh *fh;
 457
 458         dprintk("--> %s ino %lu pgbase %u req %zu@%llu\n",
 459                 __func__, hdr->inode->i_ino,
 460                 hdr->args.pgbase, (size_t)hdr->args.count, offset);
 461
 462         /* Retrieve the correct rpc_client for the byte range */
 463         j = nfs4_fl_calc_j_index(lseg, offset);
 464         idx = nfs4_fl_calc_ds_index(lseg, j);
 465         ds = nfs4_fl_prepare_ds(lseg, idx);
 466         if (!ds)
 467                 return PNFS_NOT_ATTEMPTED;
 468
 469         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, hdr->inode);
 470         if (IS_ERR(ds_clnt))
 471                 return PNFS_NOT_ATTEMPTED;
 472
 473         dprintk("%s USE DS: %s cl_count %d\n", __func__,
 474                 ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count));
 475
 476         /* No multipath support. Use first DS */
 477         atomic_inc(&ds->ds_clp->cl_count);
 478         hdr->ds_clp = ds->ds_clp;
 479         hdr->ds_commit_idx = idx;
 480         fh = nfs4_fl_select_ds_fh(lseg, j);
 481         if (fh)
 482                 hdr->args.fh = fh;
 483
 484         hdr->args.offset = filelayout_get_dserver_offset(lseg, offset);
 485         hdr->mds_offset = offset;
 486
 487         /* Perform an asynchronous read to ds */
 488         nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
 489                           NFS_PROTO(hdr->inode), &filelayout_read_call_ops,
 490                           0, RPC_TASK_SOFTCONN);
 491         return PNFS_ATTEMPTED;
 492 }
 493
 494 /* Perform async writes. */
 495 static enum pnfs_try_status
 496 filelayout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 497 {
 498         struct pnfs_layout_segment *lseg = hdr->lseg;
 499         struct nfs4_pnfs_ds *ds;
 500         struct rpc_clnt *ds_clnt;
 501         loff_t offset = hdr->args.offset;
 502         u32 j, idx;
 503         struct nfs_fh *fh;
 504
 505         /* Retrieve the correct rpc_client for the byte range */
 506         j = nfs4_fl_calc_j_index(lseg, offset);
 507         idx = nfs4_fl_calc_ds_index(lseg, j);
 508         ds = nfs4_fl_prepare_ds(lseg, idx);
 509         if (!ds)
 510                 return PNFS_NOT_ATTEMPTED;
 511
 512         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, hdr->inode);
 513         if (IS_ERR(ds_clnt))
 514                 return PNFS_NOT_ATTEMPTED;
 515
 516         dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d\n",
 517                 __func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
 518                 offset, ds->ds_remotestr, atomic_read(&ds->ds_clp->cl_count));
 519
 520         hdr->pgio_done_cb = filelayout_write_done_cb;
 521         atomic_inc(&ds->ds_clp->cl_count);
 522         hdr->ds_clp = ds->ds_clp;
 523         hdr->ds_commit_idx = idx;
 524         fh = nfs4_fl_select_ds_fh(lseg, j);
 525         if (fh)
 526                 hdr->args.fh = fh;
 527         hdr->args.offset = filelayout_get_dserver_offset(lseg, offset);
 528
 529         /* Perform an asynchronous write */
 530         nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
 531                           NFS_PROTO(hdr->inode), &filelayout_write_call_ops,
 532                           sync, RPC_TASK_SOFTCONN);
 533         return PNFS_ATTEMPTED;
 534 }
 535
 536 static int
 537 filelayout_check_deviceid(struct pnfs_layout_hdr *lo,
 538                           struct nfs4_filelayout_segment *fl,
 539                           gfp_t gfp_flags)
 540 {
 541         struct nfs4_deviceid_node *d;
 542         struct nfs4_file_layout_dsaddr *dsaddr;
 543         int status = -EINVAL;
 544
 545         /* find and reference the deviceid */
 546         d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid,
 547                         lo->plh_lc_cred, gfp_flags);
 548         if (d == NULL)
 549                 goto out;
 550
 551         dsaddr = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
 552         /* Found deviceid is unavailable */
 553         if (filelayout_test_devid_unavailable(&dsaddr->id_node))
 554                 goto out_put;
 555
 556         fl->dsaddr = dsaddr;
 557
 558         if (fl->first_stripe_index >= dsaddr->stripe_count) {
 559                 dprintk("%s Bad first_stripe_index %u\n",
 560                                 __func__, fl->first_stripe_index);
 561                 goto out_put;
 562         }
 563
 564         if ((fl->stripe_type == STRIPE_SPARSE &&
 565             fl->num_fh > 1 && fl->num_fh != dsaddr->ds_num) ||
 566             (fl->stripe_type == STRIPE_DENSE &&
 567             fl->num_fh != dsaddr->stripe_count)) {
 568                 dprintk("%s num_fh %u not valid for given packing\n",
 569                         __func__, fl->num_fh);
 570                 goto out_put;
 571         }
 572         status = 0;
 573 out:
 574         return status;
 575 out_put:
 576         nfs4_fl_put_deviceid(dsaddr);
 577         goto out;
 578 }
 579
 580 /*
 581  * filelayout_check_layout()
 582  *
 583  * Make sure layout segment parameters are sane WRT the device.
 584  * At this point no generic layer initialization of the lseg has occurred,
 585  * and nothing has been added to the layout_hdr cache.
 586  *
 587  */
 588 static int
 589 filelayout_check_layout(struct pnfs_layout_hdr *lo,
 590                         struct nfs4_filelayout_segment *fl,
 591                         struct nfs4_layoutget_res *lgr,
 592                         gfp_t gfp_flags)
 593 {
 594         int status = -EINVAL;
 595
 596         dprintk("--> %s\n", __func__);
 597
 598         /* FIXME: remove this check when layout segment support is added */
 599         if (lgr->range.offset != 0 ||
 600             lgr->range.length != NFS4_MAX_UINT64) {
 601                 dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
 602                         __func__);
 603                 goto out;
 604         }
 605
 606         if (fl->pattern_offset > lgr->range.offset) {
 607                 dprintk("%s pattern_offset %lld too large\n",
 608                                 __func__, fl->pattern_offset);
 609                 goto out;
 610         }
 611
 612         if (!fl->stripe_unit) {
 613                 dprintk("%s Invalid stripe unit (%u)\n",
 614                         __func__, fl->stripe_unit);
 615                 goto out;
 616         }
 617
 618         status = 0;
 619 out:
 620         dprintk("--> %s returns %d\n", __func__, status);
 621         return status;
 622 }
 623
 624 static void _filelayout_free_lseg(struct nfs4_filelayout_segment *fl)
 625 {
 626         int i;
 627
 628         if (fl->fh_array) {
 629                 for (i = 0; i < fl->num_fh; i++) {
 630                         if (!fl->fh_array[i])
 631                                 break;
 632                         kfree(fl->fh_array[i]);
 633                 }
 634                 kfree(fl->fh_array);
 635         }
 636         kfree(fl);
 637 }
 638
 639 static int
 640 filelayout_decode_layout(struct pnfs_layout_hdr *flo,
 641                          struct nfs4_filelayout_segment *fl,
 642                          struct nfs4_layoutget_res *lgr,
 643                          gfp_t gfp_flags)
 644 {
 645         struct xdr_stream stream;
 646         struct xdr_buf buf;
 647         struct page *scratch;
 648         __be32 *p;
 649         uint32_t nfl_util;
 650         int i;
 651
 652         dprintk("%s: set_layout_map Begin\n", __func__);
 653
 654         scratch = alloc_page(gfp_flags);
 655         if (!scratch)
 656                 return -ENOMEM;
 657
 658         xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
 659         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 660
 661         /* 20 = ufl_util (4), first_stripe_index (4), pattern_offset (8),
 662          * num_fh (4) */
 663         p = xdr_inline_decode(&stream, NFS4_DEVICEID4_SIZE + 20);
 664         if (unlikely(!p))
 665                 goto out_err;
 666
 667         memcpy(&fl->deviceid, p, sizeof(fl->deviceid));
 668         p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
 669         nfs4_print_deviceid(&fl->deviceid);
 670
 671         nfl_util = be32_to_cpup(p++);
 672         if (nfl_util & NFL4_UFLG_COMMIT_THRU_MDS)
 673                 fl->commit_through_mds = 1;
 674         if (nfl_util & NFL4_UFLG_DENSE)
 675                 fl->stripe_type = STRIPE_DENSE;
 676         else
 677                 fl->stripe_type = STRIPE_SPARSE;
 678         fl->stripe_unit = nfl_util & ~NFL4_UFLG_MASK;
 679
 680         fl->first_stripe_index = be32_to_cpup(p++);
 681         p = xdr_decode_hyper(p, &fl->pattern_offset);
 682         fl->num_fh = be32_to_cpup(p++);
 683
 684         dprintk("%s: nfl_util 0x%X num_fh %u fsi %u po %llu\n",
 685                 __func__, nfl_util, fl->num_fh, fl->first_stripe_index,
 686                 fl->pattern_offset);
 687
 688         /* Note that a zero value for num_fh is legal for STRIPE_SPARSE.
 689          * Futher checking is done in filelayout_check_layout */
 690         if (fl->num_fh >
 691             max(NFS4_PNFS_MAX_STRIPE_CNT, NFS4_PNFS_MAX_MULTI_CNT))
 692                 goto out_err;
 693
 694         if (fl->num_fh > 0) {
 695                 fl->fh_array = kcalloc(fl->num_fh, sizeof(fl->fh_array[0]),
 696                                        gfp_flags);
 697                 if (!fl->fh_array)
 698                         goto out_err;
 699         }
 700
 701         for (i = 0; i < fl->num_fh; i++) {
 702                 /* Do we want to use a mempool here? */
 703                 fl->fh_array[i] = kmalloc(sizeof(struct nfs_fh), gfp_flags);
 704                 if (!fl->fh_array[i])
 705                         goto out_err;
 706
 707                 p = xdr_inline_decode(&stream, 4);
 708                 if (unlikely(!p))
 709                         goto out_err;
 710                 fl->fh_array[i]->size = be32_to_cpup(p++);
 711                 if (sizeof(struct nfs_fh) < fl->fh_array[i]->size) {
 712                         printk(KERN_ERR "NFS: Too big fh %d received %d\n",
 713                                i, fl->fh_array[i]->size);
 714                         goto out_err;
 715                 }
 716
 717                 p = xdr_inline_decode(&stream, fl->fh_array[i]->size);
 718                 if (unlikely(!p))
 719                         goto out_err;
 720                 memcpy(fl->fh_array[i]->data, p, fl->fh_array[i]->size);
 721                 dprintk("DEBUG: %s: fh len %d\n", __func__,
 722                         fl->fh_array[i]->size);
 723         }
 724
 725         __free_page(scratch);
 726         return 0;
 727
 728 out_err:
 729         __free_page(scratch);
 730         return -EIO;
 731 }
 732
 733 static void
 734 filelayout_free_lseg(struct pnfs_layout_segment *lseg)
 735 {
 736         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 737
 738         dprintk("--> %s\n", __func__);
 739         nfs4_fl_put_deviceid(fl->dsaddr);
 740         /* This assumes a single RW lseg */
 741         if (lseg->pls_range.iomode == IOMODE_RW) {
 742                 struct nfs4_filelayout *flo;
 743
 744                 flo = FILELAYOUT_FROM_HDR(lseg->pls_layout);
 745                 flo->commit_info.nbuckets = 0;
 746                 kfree(flo->commit_info.buckets);
 747                 flo->commit_info.buckets = NULL;
 748         }
 749         _filelayout_free_lseg(fl);
 750 }
 751
 752 static int
 753 filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
 754                              struct nfs_commit_info *cinfo,
 755                              gfp_t gfp_flags)
 756 {
 757         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 758         struct pnfs_commit_bucket *buckets;
 759         int size, i;
 760
 761         if (fl->commit_through_mds)
 762                 return 0;
 763
 764         size = (fl->stripe_type == STRIPE_SPARSE) ?
 765                 fl->dsaddr->ds_num : fl->dsaddr->stripe_count;
 766
 767         if (cinfo->ds->nbuckets >= size) {
 768                 /* This assumes there is only one IOMODE_RW lseg.  What
 769                  * we really want to do is have a layout_hdr level
 770                  * dictionary of <multipath_list4, fh> keys, each
 771                  * associated with a struct list_head, populated by calls
 772                  * to filelayout_write_pagelist().
 773                  * */
 774                 return 0;
 775         }
 776
 777         buckets = kcalloc(size, sizeof(struct pnfs_commit_bucket),
 778                           gfp_flags);
 779         if (!buckets)
 780                 return -ENOMEM;
 781         for (i = 0; i < size; i++) {
 782                 INIT_LIST_HEAD(&buckets[i].written);
 783                 INIT_LIST_HEAD(&buckets[i].committing);
 784                 /* mark direct verifier as unset */
 785                 buckets[i].direct_verf.committed = NFS_INVALID_STABLE_HOW;
 786         }
 787
 788         spin_lock(&cinfo->inode->i_lock);
 789         if (cinfo->ds->nbuckets >= size)
 790                 goto out;
 791         for (i = 0; i < cinfo->ds->nbuckets; i++) {
 792                 list_splice(&cinfo->ds->buckets[i].written,
 793                             &buckets[i].written);
 794                 list_splice(&cinfo->ds->buckets[i].committing,
 795                             &buckets[i].committing);
 796                 buckets[i].direct_verf.committed =
 797                         cinfo->ds->buckets[i].direct_verf.committed;
 798                 buckets[i].wlseg = cinfo->ds->buckets[i].wlseg;
 799                 buckets[i].clseg = cinfo->ds->buckets[i].clseg;
 800         }
 801         swap(cinfo->ds->buckets, buckets);
 802         cinfo->ds->nbuckets = size;
 803 out:
 804         spin_unlock(&cinfo->inode->i_lock);
 805         kfree(buckets);
 806         return 0;
 807 }
 808
 809 static struct pnfs_layout_segment *
 810 filelayout_alloc_lseg(struct pnfs_layout_hdr *layoutid,
 811                       struct nfs4_layoutget_res *lgr,
 812                       gfp_t gfp_flags)
 813 {
 814         struct nfs4_filelayout_segment *fl;
 815         int rc;
 816
 817         dprintk("--> %s\n", __func__);
 818         fl = kzalloc(sizeof(*fl), gfp_flags);
 819         if (!fl)
 820                 return NULL;
 821
 822         rc = filelayout_decode_layout(layoutid, fl, lgr, gfp_flags);
 823         if (rc != 0 || filelayout_check_layout(layoutid, fl, lgr, gfp_flags)) {
 824                 _filelayout_free_lseg(fl);
 825                 return NULL;
 826         }
 827         return &fl->generic_hdr;
 828 }
 829
 830 /*
 831  * filelayout_pg_test(). Called by nfs_can_coalesce_requests()
 832  *
 833  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
 834  * of bytes (maximum @req->wb_bytes) that can be coalesced.
 835  */
 836 static size_t
 837 filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
 838                    struct nfs_page *req)
 839 {
 840         unsigned int size;
 841         u64 p_stripe, r_stripe;
 842         u32 stripe_offset;
 843         u64 segment_offset = pgio->pg_lseg->pls_range.offset;
 844         u32 stripe_unit = FILELAYOUT_LSEG(pgio->pg_lseg)->stripe_unit;
 845
 846         /* calls nfs_generic_pg_test */
 847         size = pnfs_generic_pg_test(pgio, prev, req);
 848         if (!size)
 849                 return 0;
 850
 851         /* see if req and prev are in the same stripe */
 852         if (prev) {
 853                 p_stripe = (u64)req_offset(prev) - segment_offset;
 854                 r_stripe = (u64)req_offset(req) - segment_offset;
 855                 do_div(p_stripe, stripe_unit);
 856                 do_div(r_stripe, stripe_unit);
 857
 858                 if (p_stripe != r_stripe)
 859                         return 0;
 860         }
 861
 862         /* calculate remaining bytes in the current stripe */
 863         div_u64_rem((u64)req_offset(req) - segment_offset,
 864                         stripe_unit,
 865                         &stripe_offset);
 866         WARN_ON_ONCE(stripe_offset > stripe_unit);
 867         if (stripe_offset >= stripe_unit)
 868                 return 0;
 869         return min(stripe_unit - (unsigned int)stripe_offset, size);
 870 }
 871
 872 static struct pnfs_layout_segment *
 873 fl_pnfs_update_layout(struct inode *ino,
 874                       struct nfs_open_context *ctx,
 875                       loff_t pos,
 876                       u64 count,
 877                       enum pnfs_iomode iomode,
 878                       bool strict_iomode,
 879                       gfp_t gfp_flags)
 880 {
 881         struct pnfs_layout_segment *lseg = NULL;
 882         struct pnfs_layout_hdr *lo;
 883         struct nfs4_filelayout_segment *fl;
 884         int status;
 885
 886         lseg = pnfs_update_layout(ino, ctx, pos, count, iomode, strict_iomode,
 887                                   gfp_flags);
 888         if (!lseg)
 889                 lseg = ERR_PTR(-ENOMEM);
 890         if (IS_ERR(lseg))
 891                 goto out;
 892
 893         lo = NFS_I(ino)->layout;
 894         fl = FILELAYOUT_LSEG(lseg);
 895
 896         status = filelayout_check_deviceid(lo, fl, gfp_flags);
 897         if (status) {
 898                 pnfs_put_lseg(lseg);
 899                 lseg = ERR_PTR(status);
 900         }
 901 out:
 902         return lseg;
 903 }
 904
 905 static void
 906 filelayout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 907                         struct nfs_page *req)
 908 {
 909         pnfs_generic_pg_check_layout(pgio);
 910         if (!pgio->pg_lseg) {
 911                 pgio->pg_lseg = fl_pnfs_update_layout(pgio->pg_inode,
 912                                                       req->wb_context,
 913                                                       0,
 914                                                       NFS4_MAX_UINT64,
 915                                                       IOMODE_READ,
 916                                                       false,
 917                                                       GFP_KERNEL);
 918                 if (IS_ERR(pgio->pg_lseg)) {
 919                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
 920                         pgio->pg_lseg = NULL;
 921                         return;
 922                 }
 923         }
 924         /* If no lseg, fall back to read through mds */
 925         if (pgio->pg_lseg == NULL)
 926                 nfs_pageio_reset_read_mds(pgio);
 927 }
 928
 929 static void
 930 filelayout_pg_init_write(struct nfs_pageio_descriptor *pgio,
 931                          struct nfs_page *req)
 932 {
 933         struct nfs_commit_info cinfo;
 934         int status;
 935
 936         pnfs_generic_pg_check_layout(pgio);
 937         if (!pgio->pg_lseg) {
 938                 pgio->pg_lseg = fl_pnfs_update_layout(pgio->pg_inode,
 939                                                       req->wb_context,
 940                                                       0,
 941                                                       NFS4_MAX_UINT64,
 942                                                       IOMODE_RW,
 943                                                       false,
 944                                                       GFP_NOFS);
 945                 if (IS_ERR(pgio->pg_lseg)) {
 946                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
 947                         pgio->pg_lseg = NULL;
 948                         return;
 949                 }
 950         }
 951
 952         /* If no lseg, fall back to write through mds */
 953         if (pgio->pg_lseg == NULL)
 954                 goto out_mds;
 955         nfs_init_cinfo(&cinfo, pgio->pg_inode, pgio->pg_dreq);
 956         status = filelayout_alloc_commit_info(pgio->pg_lseg, &cinfo, GFP_NOFS);
 957         if (status < 0) {
 958                 pnfs_put_lseg(pgio->pg_lseg);
 959                 pgio->pg_lseg = NULL;
 960                 goto out_mds;
 961         }
 962         return;
 963 out_mds:
 964         nfs_pageio_reset_write_mds(pgio);
 965 }
 966
 967 static const struct nfs_pageio_ops filelayout_pg_read_ops = {
 968         .pg_init = filelayout_pg_init_read,
 969         .pg_test = filelayout_pg_test,
 970         .pg_doio = pnfs_generic_pg_readpages,
 971         .pg_cleanup = pnfs_generic_pg_cleanup,
 972 };
 973
 974 static const struct nfs_pageio_ops filelayout_pg_write_ops = {
 975         .pg_init = filelayout_pg_init_write,
 976         .pg_test = filelayout_pg_test,
 977         .pg_doio = pnfs_generic_pg_writepages,
 978         .pg_cleanup = pnfs_generic_pg_cleanup,
 979 };
 980
 981 static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
 982 {
 983         if (fl->stripe_type == STRIPE_SPARSE)
 984                 return nfs4_fl_calc_ds_index(&fl->generic_hdr, j);
 985         else
 986                 return j;
 987 }
 988
 989 static void
 990 filelayout_mark_request_commit(struct nfs_page *req,
 991                                struct pnfs_layout_segment *lseg,
 992                                struct nfs_commit_info *cinfo,
 993                                u32 ds_commit_idx)
 994
 995 {
 996         struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg);
 997         u32 i, j;
 998
 999         if (fl->commit_through_mds) {
1000                 nfs_request_add_commit_list(req, cinfo);
1001         } else {
1002                 /* Note that we are calling nfs4_fl_calc_j_index on each page
1003                  * that ends up being committed to a data server.  An attractive
1004                  * alternative is to add a field to nfs_write_data and nfs_page
1005                  * to store the value calculated in filelayout_write_pagelist
1006                  * and just use that here.
1007                  */
1008                 j = nfs4_fl_calc_j_index(lseg, req_offset(req));
1009                 i = select_bucket_index(fl, j);
1010                 pnfs_layout_mark_request_commit(req, lseg, cinfo, i);
1011         }
1012 }
1013
1014 static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1015 {
1016         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
1017
1018         if (flseg->stripe_type == STRIPE_SPARSE)
1019                 return i;
1020         else
1021                 return nfs4_fl_calc_ds_index(lseg, i);
1022 }
1023
1024 static struct nfs_fh *
1025 select_ds_fh_from_commit(struct pnfs_layout_segment *lseg, u32 i)
1026 {
1027         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
1028
1029         if (flseg->stripe_type == STRIPE_SPARSE) {
1030                 if (flseg->num_fh == 1)
1031                         i = 0;
1032                 else if (flseg->num_fh == 0)
1033                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
1034                         return NULL;
1035         }
1036         return flseg->fh_array[i];
1037 }
1038
1039 static int filelayout_initiate_commit(struct nfs_commit_data *data, int how)
1040 {
1041         struct pnfs_layout_segment *lseg = data->lseg;
1042         struct nfs4_pnfs_ds *ds;
1043         struct rpc_clnt *ds_clnt;
1044         u32 idx;
1045         struct nfs_fh *fh;
1046
1047         idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
1048         ds = nfs4_fl_prepare_ds(lseg, idx);
1049         if (!ds)
1050                 goto out_err;
1051
1052         ds_clnt = nfs4_find_or_create_ds_client(ds->ds_clp, data->inode);
1053         if (IS_ERR(ds_clnt))
1054                 goto out_err;
1055
1056         dprintk("%s ino %lu, how %d cl_count %d\n", __func__,
1057                 data->inode->i_ino, how, atomic_read(&ds->ds_clp->cl_count));
1058         data->commit_done_cb = filelayout_commit_done_cb;
1059         atomic_inc(&ds->ds_clp->cl_count);
1060         data->ds_clp = ds->ds_clp;
1061         fh = select_ds_fh_from_commit(lseg, data->ds_commit_index);
1062         if (fh)
1063                 data->args.fh = fh;
1064         return nfs_initiate_commit(ds_clnt, data, NFS_PROTO(data->inode),
1065                                    &filelayout_commit_call_ops, how,
1066                                    RPC_TASK_SOFTCONN);
1067 out_err:
1068         pnfs_generic_prepare_to_resend_writes(data);
1069         pnfs_generic_commit_release(data);
1070         return -EAGAIN;
1071 }
1072
1073 /* filelayout_search_commit_reqs - Search lists in @cinfo for the head reqest
1074  *                                 for @page
1075  * @cinfo - commit info for current inode
1076  * @page - page to search for matching head request
1077  *
1078  * Returns a the head request if one is found, otherwise returns NULL.
1079  */
1080 static struct nfs_page *
1081 filelayout_search_commit_reqs(struct nfs_commit_info *cinfo, struct page *page)
1082 {
1083         struct nfs_page *freq, *t;
1084         struct pnfs_commit_bucket *b;
1085         int i;
1086
1087         /* Linearly search the commit lists for each bucket until a matching
1088          * request is found */
1089         for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
1090                 list_for_each_entry_safe(freq, t, &b->written, wb_list) {
1091                         if (freq->wb_page == page)
1092                                 return freq->wb_head;
1093                 }
1094                 list_for_each_entry_safe(freq, t, &b->committing, wb_list) {
1095                         if (freq->wb_page == page)
1096                                 return freq->wb_head;
1097                 }
1098         }
1099
1100         return NULL;
1101 }
1102
1103 static int
1104 filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
1105                            int how, struct nfs_commit_info *cinfo)
1106 {
1107         return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
1108                                             filelayout_initiate_commit);
1109 }
1110
1111 static struct nfs4_deviceid_node *
1112 filelayout_alloc_deviceid_node(struct nfs_server *server,
1113                 struct pnfs_device *pdev, gfp_t gfp_flags)
1114 {
1115         struct nfs4_file_layout_dsaddr *dsaddr;
1116
1117         dsaddr = nfs4_fl_alloc_deviceid_node(server, pdev, gfp_flags);
1118         if (!dsaddr)
1119                 return NULL;
1120         return &dsaddr->id_node;
1121 }
1122
1123 static void
1124 filelayout_free_deviceid_node(struct nfs4_deviceid_node *d)
1125 {
1126         nfs4_fl_free_deviceid(container_of(d, struct nfs4_file_layout_dsaddr, id_node));
1127 }
1128
1129 static struct pnfs_layout_hdr *
1130 filelayout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
1131 {
1132         struct nfs4_filelayout *flo;
1133
1134         flo = kzalloc(sizeof(*flo), gfp_flags);
1135         return flo != NULL ? &flo->generic_hdr : NULL;
1136 }
1137
1138 static void
1139 filelayout_free_layout_hdr(struct pnfs_layout_hdr *lo)
1140 {
1141         kfree(FILELAYOUT_FROM_HDR(lo));
1142 }
1143
1144 static struct pnfs_ds_commit_info *
1145 filelayout_get_ds_info(struct inode *inode)
1146 {
1147         struct pnfs_layout_hdr *layout = NFS_I(inode)->layout;
1148
1149         if (layout == NULL)
1150                 return NULL;
1151         else
1152                 return &FILELAYOUT_FROM_HDR(layout)->commit_info;
1153 }
1154
1155 static struct pnfs_layoutdriver_type filelayout_type = {
1156         .id                     = LAYOUT_NFSV4_1_FILES,
1157         .name                   = "LAYOUT_NFSV4_1_FILES",
1158         .owner                  = THIS_MODULE,
1159         .alloc_layout_hdr       = filelayout_alloc_layout_hdr,
1160         .free_layout_hdr        = filelayout_free_layout_hdr,
1161         .alloc_lseg             = filelayout_alloc_lseg,
1162         .free_lseg              = filelayout_free_lseg,
1163         .pg_read_ops            = &filelayout_pg_read_ops,
1164         .pg_write_ops           = &filelayout_pg_write_ops,
1165         .get_ds_info            = &filelayout_get_ds_info,
1166         .mark_request_commit    = filelayout_mark_request_commit,
1167         .clear_request_commit   = pnfs_generic_clear_request_commit,
1168         .scan_commit_lists      = pnfs_generic_scan_commit_lists,
1169         .recover_commit_reqs    = pnfs_generic_recover_commit_reqs,
1170         .search_commit_reqs     = filelayout_search_commit_reqs,
1171         .commit_pagelist        = filelayout_commit_pagelist,
1172         .read_pagelist          = filelayout_read_pagelist,
1173         .write_pagelist         = filelayout_write_pagelist,
1174         .alloc_deviceid_node    = filelayout_alloc_deviceid_node,
1175         .free_deviceid_node     = filelayout_free_deviceid_node,
1176         .sync                   = pnfs_nfs_generic_sync,
1177 };
1178
1179 static int __init nfs4filelayout_init(void)
1180 {
1181         printk(KERN_INFO "%s: NFSv4 File Layout Driver Registering...\n",
1182                __func__);
1183         return pnfs_register_layoutdriver(&filelayout_type);
1184 }
1185
1186 static void __exit nfs4filelayout_exit(void)
1187 {
1188         printk(KERN_INFO "%s: NFSv4 File Layout Driver Unregistering...\n",
1189                __func__);
1190         pnfs_unregister_layoutdriver(&filelayout_type);
1191 }
1192
1193 MODULE_ALIAS("nfs-layouttype4-1");
1194
1195 module_init(nfs4filelayout_init);
1196 module_exit(nfs4filelayout_exit);