linux/fs/nfs/pnfs.c
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   1/*
   2 *  pNFS functions to call and manage layout drivers.
   3 *
   4 *  Copyright (c) 2002 [year of first publication]
   5 *  The Regents of the University of Michigan
   6 *  All Rights Reserved
   7 *
   8 *  Dean Hildebrand <dhildebz@umich.edu>
   9 *
  10 *  Permission is granted to use, copy, create derivative works, and
  11 *  redistribute this software and such derivative works for any purpose,
  12 *  so long as the name of the University of Michigan is not used in
  13 *  any advertising or publicity pertaining to the use or distribution
  14 *  of this software without specific, written prior authorization. If
  15 *  the above copyright notice or any other identification of the
  16 *  University of Michigan is included in any copy of any portion of
  17 *  this software, then the disclaimer below must also be included.
  18 *
  19 *  This software is provided as is, without representation or warranty
  20 *  of any kind either express or implied, including without limitation
  21 *  the implied warranties of merchantability, fitness for a particular
  22 *  purpose, or noninfringement.  The Regents of the University of
  23 *  Michigan shall not be liable for any damages, including special,
  24 *  indirect, incidental, or consequential damages, with respect to any
  25 *  claim arising out of or in connection with the use of the software,
  26 *  even if it has been or is hereafter advised of the possibility of
  27 *  such damages.
  28 */
  29
  30#include <linux/nfs_fs.h>
  31#include <linux/nfs_page.h>
  32#include <linux/module.h>
  33#include "internal.h"
  34#include "pnfs.h"
  35#include "iostat.h"
  36
  37#define NFSDBG_FACILITY         NFSDBG_PNFS
  38#define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
  39
  40/* Locking:
  41 *
  42 * pnfs_spinlock:
  43 *      protects pnfs_modules_tbl.
  44 */
  45static DEFINE_SPINLOCK(pnfs_spinlock);
  46
  47/*
  48 * pnfs_modules_tbl holds all pnfs modules
  49 */
  50static LIST_HEAD(pnfs_modules_tbl);
  51
  52/* Return the registered pnfs layout driver module matching given id */
  53static struct pnfs_layoutdriver_type *
  54find_pnfs_driver_locked(u32 id)
  55{
  56        struct pnfs_layoutdriver_type *local;
  57
  58        list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
  59                if (local->id == id)
  60                        goto out;
  61        local = NULL;
  62out:
  63        dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
  64        return local;
  65}
  66
  67static struct pnfs_layoutdriver_type *
  68find_pnfs_driver(u32 id)
  69{
  70        struct pnfs_layoutdriver_type *local;
  71
  72        spin_lock(&pnfs_spinlock);
  73        local = find_pnfs_driver_locked(id);
  74        if (local != NULL && !try_module_get(local->owner)) {
  75                dprintk("%s: Could not grab reference on module\n", __func__);
  76                local = NULL;
  77        }
  78        spin_unlock(&pnfs_spinlock);
  79        return local;
  80}
  81
  82void
  83unset_pnfs_layoutdriver(struct nfs_server *nfss)
  84{
  85        if (nfss->pnfs_curr_ld) {
  86                if (nfss->pnfs_curr_ld->clear_layoutdriver)
  87                        nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
  88                /* Decrement the MDS count. Purge the deviceid cache if zero */
  89                if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
  90                        nfs4_deviceid_purge_client(nfss->nfs_client);
  91                module_put(nfss->pnfs_curr_ld->owner);
  92        }
  93        nfss->pnfs_curr_ld = NULL;
  94}
  95
  96/*
  97 * Try to set the server's pnfs module to the pnfs layout type specified by id.
  98 * Currently only one pNFS layout driver per filesystem is supported.
  99 *
 100 * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
 101 */
 102void
 103set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
 104                      u32 id)
 105{
 106        struct pnfs_layoutdriver_type *ld_type = NULL;
 107
 108        if (id == 0)
 109                goto out_no_driver;
 110        if (!(server->nfs_client->cl_exchange_flags &
 111                 (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
 112                printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags 0x%x\n",
 113                        __func__, id, server->nfs_client->cl_exchange_flags);
 114                goto out_no_driver;
 115        }
 116        ld_type = find_pnfs_driver(id);
 117        if (!ld_type) {
 118                request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
 119                ld_type = find_pnfs_driver(id);
 120                if (!ld_type) {
 121                        dprintk("%s: No pNFS module found for %u.\n",
 122                                __func__, id);
 123                        goto out_no_driver;
 124                }
 125        }
 126        server->pnfs_curr_ld = ld_type;
 127        if (ld_type->set_layoutdriver
 128            && ld_type->set_layoutdriver(server, mntfh)) {
 129                printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
 130                        "driver %u.\n", __func__, id);
 131                module_put(ld_type->owner);
 132                goto out_no_driver;
 133        }
 134        /* Bump the MDS count */
 135        atomic_inc(&server->nfs_client->cl_mds_count);
 136
 137        dprintk("%s: pNFS module for %u set\n", __func__, id);
 138        return;
 139
 140out_no_driver:
 141        dprintk("%s: Using NFSv4 I/O\n", __func__);
 142        server->pnfs_curr_ld = NULL;
 143}
 144
 145int
 146pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 147{
 148        int status = -EINVAL;
 149        struct pnfs_layoutdriver_type *tmp;
 150
 151        if (ld_type->id == 0) {
 152                printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
 153                return status;
 154        }
 155        if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
 156                printk(KERN_ERR "NFS: %s Layout driver must provide "
 157                       "alloc_lseg and free_lseg.\n", __func__);
 158                return status;
 159        }
 160
 161        spin_lock(&pnfs_spinlock);
 162        tmp = find_pnfs_driver_locked(ld_type->id);
 163        if (!tmp) {
 164                list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
 165                status = 0;
 166                dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
 167                        ld_type->name);
 168        } else {
 169                printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
 170                        __func__, ld_type->id);
 171        }
 172        spin_unlock(&pnfs_spinlock);
 173
 174        return status;
 175}
 176EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
 177
 178void
 179pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 180{
 181        dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
 182        spin_lock(&pnfs_spinlock);
 183        list_del(&ld_type->pnfs_tblid);
 184        spin_unlock(&pnfs_spinlock);
 185}
 186EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
 187
 188/*
 189 * pNFS client layout cache
 190 */
 191
 192/* Need to hold i_lock if caller does not already hold reference */
 193void
 194pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
 195{
 196        atomic_inc(&lo->plh_refcount);
 197}
 198
 199static struct pnfs_layout_hdr *
 200pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
 201{
 202        struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
 203        return ld->alloc_layout_hdr(ino, gfp_flags);
 204}
 205
 206static void
 207pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
 208{
 209        struct nfs_server *server = NFS_SERVER(lo->plh_inode);
 210        struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
 211
 212        if (!list_empty(&lo->plh_layouts)) {
 213                struct nfs_client *clp = server->nfs_client;
 214
 215                spin_lock(&clp->cl_lock);
 216                list_del_init(&lo->plh_layouts);
 217                spin_unlock(&clp->cl_lock);
 218        }
 219        put_rpccred(lo->plh_lc_cred);
 220        return ld->free_layout_hdr(lo);
 221}
 222
 223static void
 224pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
 225{
 226        struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
 227        dprintk("%s: freeing layout cache %p\n", __func__, lo);
 228        nfsi->layout = NULL;
 229        /* Reset MDS Threshold I/O counters */
 230        nfsi->write_io = 0;
 231        nfsi->read_io = 0;
 232}
 233
 234void
 235pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
 236{
 237        struct inode *inode = lo->plh_inode;
 238
 239        if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
 240                pnfs_detach_layout_hdr(lo);
 241                spin_unlock(&inode->i_lock);
 242                pnfs_free_layout_hdr(lo);
 243        }
 244}
 245
 246static int
 247pnfs_iomode_to_fail_bit(u32 iomode)
 248{
 249        return iomode == IOMODE_RW ?
 250                NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
 251}
 252
 253static void
 254pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 255{
 256        lo->plh_retry_timestamp = jiffies;
 257        if (!test_and_set_bit(fail_bit, &lo->plh_flags))
 258                atomic_inc(&lo->plh_refcount);
 259}
 260
 261static void
 262pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 263{
 264        if (test_and_clear_bit(fail_bit, &lo->plh_flags))
 265                atomic_dec(&lo->plh_refcount);
 266}
 267
 268static void
 269pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 270{
 271        struct inode *inode = lo->plh_inode;
 272        struct pnfs_layout_range range = {
 273                .iomode = iomode,
 274                .offset = 0,
 275                .length = NFS4_MAX_UINT64,
 276        };
 277        LIST_HEAD(head);
 278
 279        spin_lock(&inode->i_lock);
 280        pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
 281        pnfs_mark_matching_lsegs_invalid(lo, &head, &range);
 282        spin_unlock(&inode->i_lock);
 283        pnfs_free_lseg_list(&head);
 284        dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
 285                        iomode == IOMODE_RW ?  "RW" : "READ");
 286}
 287
 288static bool
 289pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 290{
 291        unsigned long start, end;
 292        int fail_bit = pnfs_iomode_to_fail_bit(iomode);
 293
 294        if (test_bit(fail_bit, &lo->plh_flags) == 0)
 295                return false;
 296        end = jiffies;
 297        start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
 298        if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
 299                /* It is time to retry the failed layoutgets */
 300                pnfs_layout_clear_fail_bit(lo, fail_bit);
 301                return false;
 302        }
 303        return true;
 304}
 305
 306static void
 307init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
 308{
 309        INIT_LIST_HEAD(&lseg->pls_list);
 310        INIT_LIST_HEAD(&lseg->pls_lc_list);
 311        atomic_set(&lseg->pls_refcount, 1);
 312        smp_mb();
 313        set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
 314        lseg->pls_layout = lo;
 315}
 316
 317static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
 318{
 319        struct inode *ino = lseg->pls_layout->plh_inode;
 320
 321        NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
 322}
 323
 324static void
 325pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
 326                struct pnfs_layout_segment *lseg)
 327{
 328        struct inode *inode = lo->plh_inode;
 329
 330        WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 331        list_del_init(&lseg->pls_list);
 332        /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
 333        atomic_dec(&lo->plh_refcount);
 334        if (list_empty(&lo->plh_segs))
 335                clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
 336        rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
 337}
 338
 339void
 340pnfs_put_lseg(struct pnfs_layout_segment *lseg)
 341{
 342        struct pnfs_layout_hdr *lo;
 343        struct inode *inode;
 344
 345        if (!lseg)
 346                return;
 347
 348        dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
 349                atomic_read(&lseg->pls_refcount),
 350                test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 351        lo = lseg->pls_layout;
 352        inode = lo->plh_inode;
 353        if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
 354                pnfs_get_layout_hdr(lo);
 355                pnfs_layout_remove_lseg(lo, lseg);
 356                spin_unlock(&inode->i_lock);
 357                pnfs_free_lseg(lseg);
 358                pnfs_put_layout_hdr(lo);
 359        }
 360}
 361EXPORT_SYMBOL_GPL(pnfs_put_lseg);
 362
 363static inline u64
 364end_offset(u64 start, u64 len)
 365{
 366        u64 end;
 367
 368        end = start + len;
 369        return end >= start ? end : NFS4_MAX_UINT64;
 370}
 371
 372/* last octet in a range */
 373static inline u64
 374last_byte_offset(u64 start, u64 len)
 375{
 376        u64 end;
 377
 378        BUG_ON(!len);
 379        end = start + len;
 380        return end > start ? end - 1 : NFS4_MAX_UINT64;
 381}
 382
 383/*
 384 * is l2 fully contained in l1?
 385 *   start1                             end1
 386 *   [----------------------------------)
 387 *           start2           end2
 388 *           [----------------)
 389 */
 390static inline int
 391lo_seg_contained(struct pnfs_layout_range *l1,
 392                 struct pnfs_layout_range *l2)
 393{
 394        u64 start1 = l1->offset;
 395        u64 end1 = end_offset(start1, l1->length);
 396        u64 start2 = l2->offset;
 397        u64 end2 = end_offset(start2, l2->length);
 398
 399        return (start1 <= start2) && (end1 >= end2);
 400}
 401
 402/*
 403 * is l1 and l2 intersecting?
 404 *   start1                             end1
 405 *   [----------------------------------)
 406 *                              start2           end2
 407 *                              [----------------)
 408 */
 409static inline int
 410lo_seg_intersecting(struct pnfs_layout_range *l1,
 411                    struct pnfs_layout_range *l2)
 412{
 413        u64 start1 = l1->offset;
 414        u64 end1 = end_offset(start1, l1->length);
 415        u64 start2 = l2->offset;
 416        u64 end2 = end_offset(start2, l2->length);
 417
 418        return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
 419               (end2 == NFS4_MAX_UINT64 || end2 > start1);
 420}
 421
 422static bool
 423should_free_lseg(struct pnfs_layout_range *lseg_range,
 424                 struct pnfs_layout_range *recall_range)
 425{
 426        return (recall_range->iomode == IOMODE_ANY ||
 427                lseg_range->iomode == recall_range->iomode) &&
 428               lo_seg_intersecting(lseg_range, recall_range);
 429}
 430
 431/* Returns 1 if lseg is removed from list, 0 otherwise */
 432static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
 433                             struct list_head *tmp_list)
 434{
 435        int rv = 0;
 436
 437        if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
 438                /* Remove the reference keeping the lseg in the
 439                 * list.  It will now be removed when all
 440                 * outstanding io is finished.
 441                 */
 442                dprintk("%s: lseg %p ref %d\n", __func__, lseg,
 443                        atomic_read(&lseg->pls_refcount));
 444                if (atomic_dec_and_test(&lseg->pls_refcount)) {
 445                        pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
 446                        list_add(&lseg->pls_list, tmp_list);
 447                        rv = 1;
 448                }
 449        }
 450        return rv;
 451}
 452
 453/* Returns count of number of matching invalid lsegs remaining in list
 454 * after call.
 455 */
 456int
 457pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
 458                            struct list_head *tmp_list,
 459                            struct pnfs_layout_range *recall_range)
 460{
 461        struct pnfs_layout_segment *lseg, *next;
 462        int invalid = 0, removed = 0;
 463
 464        dprintk("%s:Begin lo %p\n", __func__, lo);
 465
 466        if (list_empty(&lo->plh_segs))
 467                return 0;
 468        list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
 469                if (!recall_range ||
 470                    should_free_lseg(&lseg->pls_range, recall_range)) {
 471                        dprintk("%s: freeing lseg %p iomode %d "
 472                                "offset %llu length %llu\n", __func__,
 473                                lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
 474                                lseg->pls_range.length);
 475                        invalid++;
 476                        removed += mark_lseg_invalid(lseg, tmp_list);
 477                }
 478        dprintk("%s:Return %i\n", __func__, invalid - removed);
 479        return invalid - removed;
 480}
 481
 482/* note free_me must contain lsegs from a single layout_hdr */
 483void
 484pnfs_free_lseg_list(struct list_head *free_me)
 485{
 486        struct pnfs_layout_segment *lseg, *tmp;
 487
 488        if (list_empty(free_me))
 489                return;
 490
 491        list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
 492                list_del(&lseg->pls_list);
 493                pnfs_free_lseg(lseg);
 494        }
 495}
 496
 497void
 498pnfs_destroy_layout(struct nfs_inode *nfsi)
 499{
 500        struct pnfs_layout_hdr *lo;
 501        LIST_HEAD(tmp_list);
 502
 503        spin_lock(&nfsi->vfs_inode.i_lock);
 504        lo = nfsi->layout;
 505        if (lo) {
 506                lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
 507                pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
 508                pnfs_get_layout_hdr(lo);
 509                pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
 510                pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
 511                spin_unlock(&nfsi->vfs_inode.i_lock);
 512                pnfs_free_lseg_list(&tmp_list);
 513                pnfs_put_layout_hdr(lo);
 514        } else
 515                spin_unlock(&nfsi->vfs_inode.i_lock);
 516}
 517EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
 518
 519/*
 520 * Called by the state manger to remove all layouts established under an
 521 * expired lease.
 522 */
 523void
 524pnfs_destroy_all_layouts(struct nfs_client *clp)
 525{
 526        struct nfs_server *server;
 527        struct pnfs_layout_hdr *lo;
 528        LIST_HEAD(tmp_list);
 529
 530        nfs4_deviceid_mark_client_invalid(clp);
 531        nfs4_deviceid_purge_client(clp);
 532
 533        spin_lock(&clp->cl_lock);
 534        rcu_read_lock();
 535        list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 536                if (!list_empty(&server->layouts))
 537                        list_splice_init(&server->layouts, &tmp_list);
 538        }
 539        rcu_read_unlock();
 540        spin_unlock(&clp->cl_lock);
 541
 542        while (!list_empty(&tmp_list)) {
 543                lo = list_entry(tmp_list.next, struct pnfs_layout_hdr,
 544                                plh_layouts);
 545                dprintk("%s freeing layout for inode %lu\n", __func__,
 546                        lo->plh_inode->i_ino);
 547                list_del_init(&lo->plh_layouts);
 548                pnfs_destroy_layout(NFS_I(lo->plh_inode));
 549        }
 550}
 551
 552/*
 553 * Compare 2 layout stateid sequence ids, to see which is newer,
 554 * taking into account wraparound issues.
 555 */
 556static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
 557{
 558        return (s32)s1 - (s32)s2 > 0;
 559}
 560
 561/* update lo->plh_stateid with new if is more recent */
 562void
 563pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
 564                        bool update_barrier)
 565{
 566        u32 oldseq, newseq, new_barrier;
 567        int empty = list_empty(&lo->plh_segs);
 568
 569        oldseq = be32_to_cpu(lo->plh_stateid.seqid);
 570        newseq = be32_to_cpu(new->seqid);
 571        if (empty || pnfs_seqid_is_newer(newseq, oldseq)) {
 572                nfs4_stateid_copy(&lo->plh_stateid, new);
 573                if (update_barrier) {
 574                        new_barrier = be32_to_cpu(new->seqid);
 575                } else {
 576                        /* Because of wraparound, we want to keep the barrier
 577                         * "close" to the current seqids.
 578                         */
 579                        new_barrier = newseq - atomic_read(&lo->plh_outstanding);
 580                }
 581                if (empty || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
 582                        lo->plh_barrier = new_barrier;
 583        }
 584}
 585
 586static bool
 587pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
 588                const nfs4_stateid *stateid)
 589{
 590        u32 seqid = be32_to_cpu(stateid->seqid);
 591
 592        return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
 593}
 594
 595/* lget is set to 1 if called from inside send_layoutget call chain */
 596static bool
 597pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo, int lget)
 598{
 599        return lo->plh_block_lgets ||
 600                test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
 601                (list_empty(&lo->plh_segs) &&
 602                 (atomic_read(&lo->plh_outstanding) > lget));
 603}
 604
 605int
 606pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
 607                              struct nfs4_state *open_state)
 608{
 609        int status = 0;
 610
 611        dprintk("--> %s\n", __func__);
 612        spin_lock(&lo->plh_inode->i_lock);
 613        if (pnfs_layoutgets_blocked(lo, 1)) {
 614                status = -EAGAIN;
 615        } else if (list_empty(&lo->plh_segs)) {
 616                int seq;
 617
 618                do {
 619                        seq = read_seqbegin(&open_state->seqlock);
 620                        nfs4_stateid_copy(dst, &open_state->stateid);
 621                } while (read_seqretry(&open_state->seqlock, seq));
 622        } else
 623                nfs4_stateid_copy(dst, &lo->plh_stateid);
 624        spin_unlock(&lo->plh_inode->i_lock);
 625        dprintk("<-- %s\n", __func__);
 626        return status;
 627}
 628
 629/*
 630* Get layout from server.
 631*    for now, assume that whole file layouts are requested.
 632*    arg->offset: 0
 633*    arg->length: all ones
 634*/
 635static struct pnfs_layout_segment *
 636send_layoutget(struct pnfs_layout_hdr *lo,
 637           struct nfs_open_context *ctx,
 638           struct pnfs_layout_range *range,
 639           gfp_t gfp_flags)
 640{
 641        struct inode *ino = lo->plh_inode;
 642        struct nfs_server *server = NFS_SERVER(ino);
 643        struct nfs4_layoutget *lgp;
 644        struct pnfs_layout_segment *lseg;
 645
 646        dprintk("--> %s\n", __func__);
 647
 648        BUG_ON(ctx == NULL);
 649        lgp = kzalloc(sizeof(*lgp), gfp_flags);
 650        if (lgp == NULL)
 651                return NULL;
 652
 653        lgp->args.minlength = PAGE_CACHE_SIZE;
 654        if (lgp->args.minlength > range->length)
 655                lgp->args.minlength = range->length;
 656        lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
 657        lgp->args.range = *range;
 658        lgp->args.type = server->pnfs_curr_ld->id;
 659        lgp->args.inode = ino;
 660        lgp->args.ctx = get_nfs_open_context(ctx);
 661        lgp->gfp_flags = gfp_flags;
 662
 663        /* Synchronously retrieve layout information from server and
 664         * store in lseg.
 665         */
 666        lseg = nfs4_proc_layoutget(lgp, gfp_flags);
 667        if (IS_ERR(lseg)) {
 668                switch (PTR_ERR(lseg)) {
 669                case -ENOMEM:
 670                case -ERESTARTSYS:
 671                        break;
 672                default:
 673                        /* remember that LAYOUTGET failed and suspend trying */
 674                        pnfs_layout_io_set_failed(lo, range->iomode);
 675                }
 676                return NULL;
 677        }
 678
 679        return lseg;
 680}
 681
 682/*
 683 * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
 684 * when the layout segment list is empty.
 685 *
 686 * Note that a pnfs_layout_hdr can exist with an empty layout segment
 687 * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
 688 * deviceid is marked invalid.
 689 */
 690int
 691_pnfs_return_layout(struct inode *ino)
 692{
 693        struct pnfs_layout_hdr *lo = NULL;
 694        struct nfs_inode *nfsi = NFS_I(ino);
 695        LIST_HEAD(tmp_list);
 696        struct nfs4_layoutreturn *lrp;
 697        nfs4_stateid stateid;
 698        int status = 0, empty;
 699
 700        dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
 701
 702        spin_lock(&ino->i_lock);
 703        lo = nfsi->layout;
 704        if (!lo) {
 705                spin_unlock(&ino->i_lock);
 706                dprintk("NFS: %s no layout to return\n", __func__);
 707                goto out;
 708        }
 709        stateid = nfsi->layout->plh_stateid;
 710        /* Reference matched in nfs4_layoutreturn_release */
 711        pnfs_get_layout_hdr(lo);
 712        empty = list_empty(&lo->plh_segs);
 713        pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
 714        /* Don't send a LAYOUTRETURN if list was initially empty */
 715        if (empty) {
 716                spin_unlock(&ino->i_lock);
 717                pnfs_put_layout_hdr(lo);
 718                dprintk("NFS: %s no layout segments to return\n", __func__);
 719                goto out;
 720        }
 721        lo->plh_block_lgets++;
 722        spin_unlock(&ino->i_lock);
 723        pnfs_free_lseg_list(&tmp_list);
 724
 725        WARN_ON(test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags));
 726
 727        lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
 728        if (unlikely(lrp == NULL)) {
 729                status = -ENOMEM;
 730                spin_lock(&ino->i_lock);
 731                lo->plh_block_lgets--;
 732                spin_unlock(&ino->i_lock);
 733                pnfs_put_layout_hdr(lo);
 734                goto out;
 735        }
 736
 737        lrp->args.stateid = stateid;
 738        lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
 739        lrp->args.inode = ino;
 740        lrp->args.layout = lo;
 741        lrp->clp = NFS_SERVER(ino)->nfs_client;
 742
 743        status = nfs4_proc_layoutreturn(lrp);
 744out:
 745        dprintk("<-- %s status: %d\n", __func__, status);
 746        return status;
 747}
 748EXPORT_SYMBOL_GPL(_pnfs_return_layout);
 749
 750bool pnfs_roc(struct inode *ino)
 751{
 752        struct pnfs_layout_hdr *lo;
 753        struct pnfs_layout_segment *lseg, *tmp;
 754        LIST_HEAD(tmp_list);
 755        bool found = false;
 756
 757        spin_lock(&ino->i_lock);
 758        lo = NFS_I(ino)->layout;
 759        if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
 760            test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
 761                goto out_nolayout;
 762        list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
 763                if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
 764                        mark_lseg_invalid(lseg, &tmp_list);
 765                        found = true;
 766                }
 767        if (!found)
 768                goto out_nolayout;
 769        lo->plh_block_lgets++;
 770        pnfs_get_layout_hdr(lo); /* matched in pnfs_roc_release */
 771        spin_unlock(&ino->i_lock);
 772        pnfs_free_lseg_list(&tmp_list);
 773        return true;
 774
 775out_nolayout:
 776        spin_unlock(&ino->i_lock);
 777        return false;
 778}
 779
 780void pnfs_roc_release(struct inode *ino)
 781{
 782        struct pnfs_layout_hdr *lo;
 783
 784        spin_lock(&ino->i_lock);
 785        lo = NFS_I(ino)->layout;
 786        lo->plh_block_lgets--;
 787        if (atomic_dec_and_test(&lo->plh_refcount)) {
 788                pnfs_detach_layout_hdr(lo);
 789                spin_unlock(&ino->i_lock);
 790                pnfs_free_layout_hdr(lo);
 791        } else
 792                spin_unlock(&ino->i_lock);
 793}
 794
 795void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
 796{
 797        struct pnfs_layout_hdr *lo;
 798
 799        spin_lock(&ino->i_lock);
 800        lo = NFS_I(ino)->layout;
 801        if (pnfs_seqid_is_newer(barrier, lo->plh_barrier))
 802                lo->plh_barrier = barrier;
 803        spin_unlock(&ino->i_lock);
 804}
 805
 806bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task)
 807{
 808        struct nfs_inode *nfsi = NFS_I(ino);
 809        struct pnfs_layout_hdr *lo;
 810        struct pnfs_layout_segment *lseg;
 811        u32 current_seqid;
 812        bool found = false;
 813
 814        spin_lock(&ino->i_lock);
 815        list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list)
 816                if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
 817                        rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
 818                        found = true;
 819                        goto out;
 820                }
 821        lo = nfsi->layout;
 822        current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
 823
 824        /* Since close does not return a layout stateid for use as
 825         * a barrier, we choose the worst-case barrier.
 826         */
 827        *barrier = current_seqid + atomic_read(&lo->plh_outstanding);
 828out:
 829        spin_unlock(&ino->i_lock);
 830        return found;
 831}
 832
 833/*
 834 * Compare two layout segments for sorting into layout cache.
 835 * We want to preferentially return RW over RO layouts, so ensure those
 836 * are seen first.
 837 */
 838static s64
 839cmp_layout(struct pnfs_layout_range *l1,
 840           struct pnfs_layout_range *l2)
 841{
 842        s64 d;
 843
 844        /* high offset > low offset */
 845        d = l1->offset - l2->offset;
 846        if (d)
 847                return d;
 848
 849        /* short length > long length */
 850        d = l2->length - l1->length;
 851        if (d)
 852                return d;
 853
 854        /* read > read/write */
 855        return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
 856}
 857
 858static void
 859pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
 860                   struct pnfs_layout_segment *lseg)
 861{
 862        struct pnfs_layout_segment *lp;
 863
 864        dprintk("%s:Begin\n", __func__);
 865
 866        list_for_each_entry(lp, &lo->plh_segs, pls_list) {
 867                if (cmp_layout(&lseg->pls_range, &lp->pls_range) > 0)
 868                        continue;
 869                list_add_tail(&lseg->pls_list, &lp->pls_list);
 870                dprintk("%s: inserted lseg %p "
 871                        "iomode %d offset %llu length %llu before "
 872                        "lp %p iomode %d offset %llu length %llu\n",
 873                        __func__, lseg, lseg->pls_range.iomode,
 874                        lseg->pls_range.offset, lseg->pls_range.length,
 875                        lp, lp->pls_range.iomode, lp->pls_range.offset,
 876                        lp->pls_range.length);
 877                goto out;
 878        }
 879        list_add_tail(&lseg->pls_list, &lo->plh_segs);
 880        dprintk("%s: inserted lseg %p "
 881                "iomode %d offset %llu length %llu at tail\n",
 882                __func__, lseg, lseg->pls_range.iomode,
 883                lseg->pls_range.offset, lseg->pls_range.length);
 884out:
 885        pnfs_get_layout_hdr(lo);
 886
 887        dprintk("%s:Return\n", __func__);
 888}
 889
 890static struct pnfs_layout_hdr *
 891alloc_init_layout_hdr(struct inode *ino,
 892                      struct nfs_open_context *ctx,
 893                      gfp_t gfp_flags)
 894{
 895        struct pnfs_layout_hdr *lo;
 896
 897        lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
 898        if (!lo)
 899                return NULL;
 900        atomic_set(&lo->plh_refcount, 1);
 901        INIT_LIST_HEAD(&lo->plh_layouts);
 902        INIT_LIST_HEAD(&lo->plh_segs);
 903        INIT_LIST_HEAD(&lo->plh_bulk_recall);
 904        lo->plh_inode = ino;
 905        lo->plh_lc_cred = get_rpccred(ctx->state->owner->so_cred);
 906        return lo;
 907}
 908
 909static struct pnfs_layout_hdr *
 910pnfs_find_alloc_layout(struct inode *ino,
 911                       struct nfs_open_context *ctx,
 912                       gfp_t gfp_flags)
 913{
 914        struct nfs_inode *nfsi = NFS_I(ino);
 915        struct pnfs_layout_hdr *new = NULL;
 916
 917        dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
 918
 919        if (nfsi->layout != NULL)
 920                goto out_existing;
 921        spin_unlock(&ino->i_lock);
 922        new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
 923        spin_lock(&ino->i_lock);
 924
 925        if (likely(nfsi->layout == NULL)) {     /* Won the race? */
 926                nfsi->layout = new;
 927                return new;
 928        } else if (new != NULL)
 929                pnfs_free_layout_hdr(new);
 930out_existing:
 931        pnfs_get_layout_hdr(nfsi->layout);
 932        return nfsi->layout;
 933}
 934
 935/*
 936 * iomode matching rules:
 937 * iomode       lseg    match
 938 * -----        -----   -----
 939 * ANY          READ    true
 940 * ANY          RW      true
 941 * RW           READ    false
 942 * RW           RW      true
 943 * READ         READ    true
 944 * READ         RW      true
 945 */
 946static int
 947is_matching_lseg(struct pnfs_layout_range *ls_range,
 948                 struct pnfs_layout_range *range)
 949{
 950        struct pnfs_layout_range range1;
 951
 952        if ((range->iomode == IOMODE_RW &&
 953             ls_range->iomode != IOMODE_RW) ||
 954            !lo_seg_intersecting(ls_range, range))
 955                return 0;
 956
 957        /* range1 covers only the first byte in the range */
 958        range1 = *range;
 959        range1.length = 1;
 960        return lo_seg_contained(ls_range, &range1);
 961}
 962
 963/*
 964 * lookup range in layout
 965 */
 966static struct pnfs_layout_segment *
 967pnfs_find_lseg(struct pnfs_layout_hdr *lo,
 968                struct pnfs_layout_range *range)
 969{
 970        struct pnfs_layout_segment *lseg, *ret = NULL;
 971
 972        dprintk("%s:Begin\n", __func__);
 973
 974        list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
 975                if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
 976                    is_matching_lseg(&lseg->pls_range, range)) {
 977                        ret = pnfs_get_lseg(lseg);
 978                        break;
 979                }
 980                if (lseg->pls_range.offset > range->offset)
 981                        break;
 982        }
 983
 984        dprintk("%s:Return lseg %p ref %d\n",
 985                __func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
 986        return ret;
 987}
 988
 989/*
 990 * Use mdsthreshold hints set at each OPEN to determine if I/O should go
 991 * to the MDS or over pNFS
 992 *
 993 * The nfs_inode read_io and write_io fields are cumulative counters reset
 994 * when there are no layout segments. Note that in pnfs_update_layout iomode
 995 * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
 996 * WRITE request.
 997 *
 998 * A return of true means use MDS I/O.
 999 *
1000 * From rfc 5661:
1001 * If a file's size is smaller than the file size threshold, data accesses
1002 * SHOULD be sent to the metadata server.  If an I/O request has a length that
1003 * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1004 * server.  If both file size and I/O size are provided, the client SHOULD
1005 * reach or exceed  both thresholds before sending its read or write
1006 * requests to the data server.
1007 */
1008static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1009                                     struct inode *ino, int iomode)
1010{
1011        struct nfs4_threshold *t = ctx->mdsthreshold;
1012        struct nfs_inode *nfsi = NFS_I(ino);
1013        loff_t fsize = i_size_read(ino);
1014        bool size = false, size_set = false, io = false, io_set = false, ret = false;
1015
1016        if (t == NULL)
1017                return ret;
1018
1019        dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1020                __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1021
1022        switch (iomode) {
1023        case IOMODE_READ:
1024                if (t->bm & THRESHOLD_RD) {
1025                        dprintk("%s fsize %llu\n", __func__, fsize);
1026                        size_set = true;
1027                        if (fsize < t->rd_sz)
1028                                size = true;
1029                }
1030                if (t->bm & THRESHOLD_RD_IO) {
1031                        dprintk("%s nfsi->read_io %llu\n", __func__,
1032                                nfsi->read_io);
1033                        io_set = true;
1034                        if (nfsi->read_io < t->rd_io_sz)
1035                                io = true;
1036                }
1037                break;
1038        case IOMODE_RW:
1039                if (t->bm & THRESHOLD_WR) {
1040                        dprintk("%s fsize %llu\n", __func__, fsize);
1041                        size_set = true;
1042                        if (fsize < t->wr_sz)
1043                                size = true;
1044                }
1045                if (t->bm & THRESHOLD_WR_IO) {
1046                        dprintk("%s nfsi->write_io %llu\n", __func__,
1047                                nfsi->write_io);
1048                        io_set = true;
1049                        if (nfsi->write_io < t->wr_io_sz)
1050                                io = true;
1051                }
1052                break;
1053        }
1054        if (size_set && io_set) {
1055                if (size && io)
1056                        ret = true;
1057        } else if (size || io)
1058                ret = true;
1059
1060        dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
1061        return ret;
1062}
1063
1064/*
1065 * Layout segment is retreived from the server if not cached.
1066 * The appropriate layout segment is referenced and returned to the caller.
1067 */
1068struct pnfs_layout_segment *
1069pnfs_update_layout(struct inode *ino,
1070                   struct nfs_open_context *ctx,
1071                   loff_t pos,
1072                   u64 count,
1073                   enum pnfs_iomode iomode,
1074                   gfp_t gfp_flags)
1075{
1076        struct pnfs_layout_range arg = {
1077                .iomode = iomode,
1078                .offset = pos,
1079                .length = count,
1080        };
1081        unsigned pg_offset;
1082        struct nfs_server *server = NFS_SERVER(ino);
1083        struct nfs_client *clp = server->nfs_client;
1084        struct pnfs_layout_hdr *lo;
1085        struct pnfs_layout_segment *lseg = NULL;
1086        bool first = false;
1087
1088        if (!pnfs_enabled_sb(NFS_SERVER(ino)))
1089                goto out;
1090
1091        if (pnfs_within_mdsthreshold(ctx, ino, iomode))
1092                goto out;
1093
1094        spin_lock(&ino->i_lock);
1095        lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
1096        if (lo == NULL) {
1097                spin_unlock(&ino->i_lock);
1098                goto out;
1099        }
1100
1101        /* Do we even need to bother with this? */
1102        if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1103                dprintk("%s matches recall, use MDS\n", __func__);
1104                goto out_unlock;
1105        }
1106
1107        /* if LAYOUTGET already failed once we don't try again */
1108        if (pnfs_layout_io_test_failed(lo, iomode))
1109                goto out_unlock;
1110
1111        /* Check to see if the layout for the given range already exists */
1112        lseg = pnfs_find_lseg(lo, &arg);
1113        if (lseg)
1114                goto out_unlock;
1115
1116        if (pnfs_layoutgets_blocked(lo, 0))
1117                goto out_unlock;
1118        atomic_inc(&lo->plh_outstanding);
1119
1120        if (list_empty(&lo->plh_segs))
1121                first = true;
1122
1123        spin_unlock(&ino->i_lock);
1124        if (first) {
1125                /* The lo must be on the clp list if there is any
1126                 * chance of a CB_LAYOUTRECALL(FILE) coming in.
1127                 */
1128                spin_lock(&clp->cl_lock);
1129                BUG_ON(!list_empty(&lo->plh_layouts));
1130                list_add_tail(&lo->plh_layouts, &server->layouts);
1131                spin_unlock(&clp->cl_lock);
1132        }
1133
1134        pg_offset = arg.offset & ~PAGE_CACHE_MASK;
1135        if (pg_offset) {
1136                arg.offset -= pg_offset;
1137                arg.length += pg_offset;
1138        }
1139        if (arg.length != NFS4_MAX_UINT64)
1140                arg.length = PAGE_CACHE_ALIGN(arg.length);
1141
1142        lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
1143        atomic_dec(&lo->plh_outstanding);
1144out_put_layout_hdr:
1145        pnfs_put_layout_hdr(lo);
1146out:
1147        dprintk("%s: inode %s/%llu pNFS layout segment %s for "
1148                        "(%s, offset: %llu, length: %llu)\n",
1149                        __func__, ino->i_sb->s_id,
1150                        (unsigned long long)NFS_FILEID(ino),
1151                        lseg == NULL ? "not found" : "found",
1152                        iomode==IOMODE_RW ?  "read/write" : "read-only",
1153                        (unsigned long long)pos,
1154                        (unsigned long long)count);
1155        return lseg;
1156out_unlock:
1157        spin_unlock(&ino->i_lock);
1158        goto out_put_layout_hdr;
1159}
1160EXPORT_SYMBOL_GPL(pnfs_update_layout);
1161
1162struct pnfs_layout_segment *
1163pnfs_layout_process(struct nfs4_layoutget *lgp)
1164{
1165        struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
1166        struct nfs4_layoutget_res *res = &lgp->res;
1167        struct pnfs_layout_segment *lseg;
1168        struct inode *ino = lo->plh_inode;
1169        int status = 0;
1170
1171        /* Inject layout blob into I/O device driver */
1172        lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
1173        if (!lseg || IS_ERR(lseg)) {
1174                if (!lseg)
1175                        status = -ENOMEM;
1176                else
1177                        status = PTR_ERR(lseg);
1178                dprintk("%s: Could not allocate layout: error %d\n",
1179                       __func__, status);
1180                goto out;
1181        }
1182
1183        spin_lock(&ino->i_lock);
1184        if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1185                dprintk("%s forget reply due to recall\n", __func__);
1186                goto out_forget_reply;
1187        }
1188
1189        if (pnfs_layoutgets_blocked(lo, 1) ||
1190            pnfs_layout_stateid_blocked(lo, &res->stateid)) {
1191                dprintk("%s forget reply due to state\n", __func__);
1192                goto out_forget_reply;
1193        }
1194
1195        /* Done processing layoutget. Set the layout stateid */
1196        pnfs_set_layout_stateid(lo, &res->stateid, false);
1197
1198        init_lseg(lo, lseg);
1199        lseg->pls_range = res->range;
1200        pnfs_get_lseg(lseg);
1201        pnfs_layout_insert_lseg(lo, lseg);
1202
1203        if (res->return_on_close) {
1204                set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
1205                set_bit(NFS_LAYOUT_ROC, &lo->plh_flags);
1206        }
1207
1208        spin_unlock(&ino->i_lock);
1209        return lseg;
1210out:
1211        return ERR_PTR(status);
1212
1213out_forget_reply:
1214        spin_unlock(&ino->i_lock);
1215        lseg->pls_layout = lo;
1216        NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
1217        goto out;
1218}
1219
1220void
1221pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1222{
1223        u64 rd_size = req->wb_bytes;
1224
1225        BUG_ON(pgio->pg_lseg != NULL);
1226
1227        if (req->wb_offset != req->wb_pgbase) {
1228                nfs_pageio_reset_read_mds(pgio);
1229                return;
1230        }
1231
1232        if (pgio->pg_dreq == NULL)
1233                rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
1234        else
1235                rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
1236
1237        pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1238                                           req->wb_context,
1239                                           req_offset(req),
1240                                           rd_size,
1241                                           IOMODE_READ,
1242                                           GFP_KERNEL);
1243        /* If no lseg, fall back to read through mds */
1244        if (pgio->pg_lseg == NULL)
1245                nfs_pageio_reset_read_mds(pgio);
1246
1247}
1248EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
1249
1250void
1251pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
1252                           struct nfs_page *req, u64 wb_size)
1253{
1254        BUG_ON(pgio->pg_lseg != NULL);
1255
1256        if (req->wb_offset != req->wb_pgbase) {
1257                nfs_pageio_reset_write_mds(pgio);
1258                return;
1259        }
1260
1261        pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1262                                           req->wb_context,
1263                                           req_offset(req),
1264                                           wb_size,
1265                                           IOMODE_RW,
1266                                           GFP_NOFS);
1267        /* If no lseg, fall back to write through mds */
1268        if (pgio->pg_lseg == NULL)
1269                nfs_pageio_reset_write_mds(pgio);
1270}
1271EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
1272
1273void
1274pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *inode,
1275                      const struct nfs_pgio_completion_ops *compl_ops)
1276{
1277        struct nfs_server *server = NFS_SERVER(inode);
1278        struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1279
1280        if (ld == NULL)
1281                nfs_pageio_init_read(pgio, inode, compl_ops);
1282        else
1283                nfs_pageio_init(pgio, inode, ld->pg_read_ops, compl_ops, server->rsize, 0);
1284}
1285
1286void
1287pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode,
1288                       int ioflags,
1289                       const struct nfs_pgio_completion_ops *compl_ops)
1290{
1291        struct nfs_server *server = NFS_SERVER(inode);
1292        struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
1293
1294        if (ld == NULL)
1295                nfs_pageio_init_write(pgio, inode, ioflags, compl_ops);
1296        else
1297                nfs_pageio_init(pgio, inode, ld->pg_write_ops, compl_ops, server->wsize, ioflags);
1298}
1299
1300bool
1301pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
1302                     struct nfs_page *req)
1303{
1304        if (pgio->pg_lseg == NULL)
1305                return nfs_generic_pg_test(pgio, prev, req);
1306
1307        /*
1308         * Test if a nfs_page is fully contained in the pnfs_layout_range.
1309         * Note that this test makes several assumptions:
1310         * - that the previous nfs_page in the struct nfs_pageio_descriptor
1311         *   is known to lie within the range.
1312         *   - that the nfs_page being tested is known to be contiguous with the
1313         *   previous nfs_page.
1314         *   - Layout ranges are page aligned, so we only have to test the
1315         *   start offset of the request.
1316         *
1317         * Please also note that 'end_offset' is actually the offset of the
1318         * first byte that lies outside the pnfs_layout_range. FIXME?
1319         *
1320         */
1321        return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
1322                                         pgio->pg_lseg->pls_range.length);
1323}
1324EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
1325
1326int pnfs_write_done_resend_to_mds(struct inode *inode,
1327                                struct list_head *head,
1328                                const struct nfs_pgio_completion_ops *compl_ops)
1329{
1330        struct nfs_pageio_descriptor pgio;
1331        LIST_HEAD(failed);
1332
1333        /* Resend all requests through the MDS */
1334        nfs_pageio_init_write(&pgio, inode, FLUSH_STABLE, compl_ops);
1335        while (!list_empty(head)) {
1336                struct nfs_page *req = nfs_list_entry(head->next);
1337
1338                nfs_list_remove_request(req);
1339                if (!nfs_pageio_add_request(&pgio, req))
1340                        nfs_list_add_request(req, &failed);
1341        }
1342        nfs_pageio_complete(&pgio);
1343
1344        if (!list_empty(&failed)) {
1345                /* For some reason our attempt to resend pages. Mark the
1346                 * overall send request as having failed, and let
1347                 * nfs_writeback_release_full deal with the error.
1348                 */
1349                list_move(&failed, head);
1350                return -EIO;
1351        }
1352        return 0;
1353}
1354EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
1355
1356static void pnfs_ld_handle_write_error(struct nfs_write_data *data)
1357{
1358        struct nfs_pgio_header *hdr = data->header;
1359
1360        dprintk("pnfs write error = %d\n", hdr->pnfs_error);
1361        if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1362            PNFS_LAYOUTRET_ON_ERROR) {
1363                clear_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(hdr->inode)->flags);
1364                pnfs_return_layout(hdr->inode);
1365        }
1366        if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1367                data->task.tk_status = pnfs_write_done_resend_to_mds(hdr->inode,
1368                                                        &hdr->pages,
1369                                                        hdr->completion_ops);
1370}
1371
1372/*
1373 * Called by non rpc-based layout drivers
1374 */
1375void pnfs_ld_write_done(struct nfs_write_data *data)
1376{
1377        struct nfs_pgio_header *hdr = data->header;
1378
1379        if (!hdr->pnfs_error) {
1380                pnfs_set_layoutcommit(data);
1381                hdr->mds_ops->rpc_call_done(&data->task, data);
1382        } else
1383                pnfs_ld_handle_write_error(data);
1384        hdr->mds_ops->rpc_release(data);
1385}
1386EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
1387
1388static void
1389pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
1390                struct nfs_write_data *data)
1391{
1392        struct nfs_pgio_header *hdr = data->header;
1393
1394        if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1395                list_splice_tail_init(&hdr->pages, &desc->pg_list);
1396                nfs_pageio_reset_write_mds(desc);
1397                desc->pg_recoalesce = 1;
1398        }
1399        nfs_writedata_release(data);
1400}
1401
1402static enum pnfs_try_status
1403pnfs_try_to_write_data(struct nfs_write_data *wdata,
1404                        const struct rpc_call_ops *call_ops,
1405                        struct pnfs_layout_segment *lseg,
1406                        int how)
1407{
1408        struct nfs_pgio_header *hdr = wdata->header;
1409        struct inode *inode = hdr->inode;
1410        enum pnfs_try_status trypnfs;
1411        struct nfs_server *nfss = NFS_SERVER(inode);
1412
1413        hdr->mds_ops = call_ops;
1414
1415        dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
1416                inode->i_ino, wdata->args.count, wdata->args.offset, how);
1417        trypnfs = nfss->pnfs_curr_ld->write_pagelist(wdata, how);
1418        if (trypnfs != PNFS_NOT_ATTEMPTED)
1419                nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
1420        dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1421        return trypnfs;
1422}
1423
1424static void
1425pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *head, int how)
1426{
1427        struct nfs_write_data *data;
1428        const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1429        struct pnfs_layout_segment *lseg = desc->pg_lseg;
1430
1431        desc->pg_lseg = NULL;
1432        while (!list_empty(head)) {
1433                enum pnfs_try_status trypnfs;
1434
1435                data = list_first_entry(head, struct nfs_write_data, list);
1436                list_del_init(&data->list);
1437
1438                trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
1439                if (trypnfs == PNFS_NOT_ATTEMPTED)
1440                        pnfs_write_through_mds(desc, data);
1441        }
1442        pnfs_put_lseg(lseg);
1443}
1444
1445static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
1446{
1447        pnfs_put_lseg(hdr->lseg);
1448        nfs_writehdr_free(hdr);
1449}
1450EXPORT_SYMBOL_GPL(pnfs_writehdr_free);
1451
1452int
1453pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1454{
1455        struct nfs_write_header *whdr;
1456        struct nfs_pgio_header *hdr;
1457        int ret;
1458
1459        whdr = nfs_writehdr_alloc();
1460        if (!whdr) {
1461                desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1462                pnfs_put_lseg(desc->pg_lseg);
1463                desc->pg_lseg = NULL;
1464                return -ENOMEM;
1465        }
1466        hdr = &whdr->header;
1467        nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
1468        hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
1469        atomic_inc(&hdr->refcnt);
1470        ret = nfs_generic_flush(desc, hdr);
1471        if (ret != 0) {
1472                pnfs_put_lseg(desc->pg_lseg);
1473                desc->pg_lseg = NULL;
1474        } else
1475                pnfs_do_multiple_writes(desc, &hdr->rpc_list, desc->pg_ioflags);
1476        if (atomic_dec_and_test(&hdr->refcnt))
1477                hdr->completion_ops->completion(hdr);
1478        return ret;
1479}
1480EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
1481
1482int pnfs_read_done_resend_to_mds(struct inode *inode,
1483                                struct list_head *head,
1484                                const struct nfs_pgio_completion_ops *compl_ops)
1485{
1486        struct nfs_pageio_descriptor pgio;
1487        LIST_HEAD(failed);
1488
1489        /* Resend all requests through the MDS */
1490        nfs_pageio_init_read(&pgio, inode, compl_ops);
1491        while (!list_empty(head)) {
1492                struct nfs_page *req = nfs_list_entry(head->next);
1493
1494                nfs_list_remove_request(req);
1495                if (!nfs_pageio_add_request(&pgio, req))
1496                        nfs_list_add_request(req, &failed);
1497        }
1498        nfs_pageio_complete(&pgio);
1499
1500        if (!list_empty(&failed)) {
1501                list_move(&failed, head);
1502                return -EIO;
1503        }
1504        return 0;
1505}
1506EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
1507
1508static void pnfs_ld_handle_read_error(struct nfs_read_data *data)
1509{
1510        struct nfs_pgio_header *hdr = data->header;
1511
1512        dprintk("pnfs read error = %d\n", hdr->pnfs_error);
1513        if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1514            PNFS_LAYOUTRET_ON_ERROR) {
1515                clear_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(hdr->inode)->flags);
1516                pnfs_return_layout(hdr->inode);
1517        }
1518        if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1519                data->task.tk_status = pnfs_read_done_resend_to_mds(hdr->inode,
1520                                                        &hdr->pages,
1521                                                        hdr->completion_ops);
1522}
1523
1524/*
1525 * Called by non rpc-based layout drivers
1526 */
1527void pnfs_ld_read_done(struct nfs_read_data *data)
1528{
1529        struct nfs_pgio_header *hdr = data->header;
1530
1531        if (likely(!hdr->pnfs_error)) {
1532                __nfs4_read_done_cb(data);
1533                hdr->mds_ops->rpc_call_done(&data->task, data);
1534        } else
1535                pnfs_ld_handle_read_error(data);
1536        hdr->mds_ops->rpc_release(data);
1537}
1538EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
1539
1540static void
1541pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
1542                struct nfs_read_data *data)
1543{
1544        struct nfs_pgio_header *hdr = data->header;
1545
1546        if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1547                list_splice_tail_init(&hdr->pages, &desc->pg_list);
1548                nfs_pageio_reset_read_mds(desc);
1549                desc->pg_recoalesce = 1;
1550        }
1551        nfs_readdata_release(data);
1552}
1553
1554/*
1555 * Call the appropriate parallel I/O subsystem read function.
1556 */
1557static enum pnfs_try_status
1558pnfs_try_to_read_data(struct nfs_read_data *rdata,
1559                       const struct rpc_call_ops *call_ops,
1560                       struct pnfs_layout_segment *lseg)
1561{
1562        struct nfs_pgio_header *hdr = rdata->header;
1563        struct inode *inode = hdr->inode;
1564        struct nfs_server *nfss = NFS_SERVER(inode);
1565        enum pnfs_try_status trypnfs;
1566
1567        hdr->mds_ops = call_ops;
1568
1569        dprintk("%s: Reading ino:%lu %u@%llu\n",
1570                __func__, inode->i_ino, rdata->args.count, rdata->args.offset);
1571
1572        trypnfs = nfss->pnfs_curr_ld->read_pagelist(rdata);
1573        if (trypnfs != PNFS_NOT_ATTEMPTED)
1574                nfs_inc_stats(inode, NFSIOS_PNFS_READ);
1575        dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1576        return trypnfs;
1577}
1578
1579static void
1580pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
1581{
1582        struct nfs_read_data *data;
1583        const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1584        struct pnfs_layout_segment *lseg = desc->pg_lseg;
1585
1586        desc->pg_lseg = NULL;
1587        while (!list_empty(head)) {
1588                enum pnfs_try_status trypnfs;
1589
1590                data = list_first_entry(head, struct nfs_read_data, list);
1591                list_del_init(&data->list);
1592
1593                trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
1594                if (trypnfs == PNFS_NOT_ATTEMPTED)
1595                        pnfs_read_through_mds(desc, data);
1596        }
1597        pnfs_put_lseg(lseg);
1598}
1599
1600static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
1601{
1602        pnfs_put_lseg(hdr->lseg);
1603        nfs_readhdr_free(hdr);
1604}
1605EXPORT_SYMBOL_GPL(pnfs_readhdr_free);
1606
1607int
1608pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
1609{
1610        struct nfs_read_header *rhdr;
1611        struct nfs_pgio_header *hdr;
1612        int ret;
1613
1614        rhdr = nfs_readhdr_alloc();
1615        if (!rhdr) {
1616                desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1617                ret = -ENOMEM;
1618                pnfs_put_lseg(desc->pg_lseg);
1619                desc->pg_lseg = NULL;
1620                return ret;
1621        }
1622        hdr = &rhdr->header;
1623        nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
1624        hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
1625        atomic_inc(&hdr->refcnt);
1626        ret = nfs_generic_pagein(desc, hdr);
1627        if (ret != 0) {
1628                pnfs_put_lseg(desc->pg_lseg);
1629                desc->pg_lseg = NULL;
1630        } else
1631                pnfs_do_multiple_reads(desc, &hdr->rpc_list);
1632        if (atomic_dec_and_test(&hdr->refcnt))
1633                hdr->completion_ops->completion(hdr);
1634        return ret;
1635}
1636EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
1637
1638/*
1639 * There can be multiple RW segments.
1640 */
1641static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
1642{
1643        struct pnfs_layout_segment *lseg;
1644
1645        list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
1646                if (lseg->pls_range.iomode == IOMODE_RW &&
1647                    test_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
1648                        list_add(&lseg->pls_lc_list, listp);
1649        }
1650}
1651
1652void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
1653{
1654        pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
1655}
1656EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
1657
1658void
1659pnfs_set_layoutcommit(struct nfs_write_data *wdata)
1660{
1661        struct nfs_pgio_header *hdr = wdata->header;
1662        struct inode *inode = hdr->inode;
1663        struct nfs_inode *nfsi = NFS_I(inode);
1664        loff_t end_pos = wdata->mds_offset + wdata->res.count;
1665        bool mark_as_dirty = false;
1666
1667        spin_lock(&inode->i_lock);
1668        if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
1669                mark_as_dirty = true;
1670                dprintk("%s: Set layoutcommit for inode %lu ",
1671                        __func__, inode->i_ino);
1672        }
1673        if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &hdr->lseg->pls_flags)) {
1674                /* references matched in nfs4_layoutcommit_release */
1675                pnfs_get_lseg(hdr->lseg);
1676        }
1677        if (end_pos > nfsi->layout->plh_lwb)
1678                nfsi->layout->plh_lwb = end_pos;
1679        spin_unlock(&inode->i_lock);
1680        dprintk("%s: lseg %p end_pos %llu\n",
1681                __func__, hdr->lseg, nfsi->layout->plh_lwb);
1682
1683        /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
1684         * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
1685        if (mark_as_dirty)
1686                mark_inode_dirty_sync(inode);
1687}
1688EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
1689
1690void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
1691{
1692        struct nfs_server *nfss = NFS_SERVER(data->args.inode);
1693
1694        if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
1695                nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
1696}
1697
1698/*
1699 * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
1700 * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
1701 * data to disk to allow the server to recover the data if it crashes.
1702 * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
1703 * is off, and a COMMIT is sent to a data server, or
1704 * if WRITEs to a data server return NFS_DATA_SYNC.
1705 */
1706int
1707pnfs_layoutcommit_inode(struct inode *inode, bool sync)
1708{
1709        struct nfs4_layoutcommit_data *data;
1710        struct nfs_inode *nfsi = NFS_I(inode);
1711        loff_t end_pos;
1712        int status = 0;
1713
1714        dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
1715
1716        if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1717                return 0;
1718
1719        /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
1720        data = kzalloc(sizeof(*data), GFP_NOFS);
1721        if (!data) {
1722                status = -ENOMEM;
1723                goto out;
1724        }
1725
1726        if (!test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
1727                goto out_free;
1728
1729        if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
1730                if (!sync) {
1731                        status = -EAGAIN;
1732                        goto out_free;
1733                }
1734                status = wait_on_bit_lock(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING,
1735                                        nfs_wait_bit_killable, TASK_KILLABLE);
1736                if (status)
1737                        goto out_free;
1738        }
1739
1740        INIT_LIST_HEAD(&data->lseg_list);
1741        spin_lock(&inode->i_lock);
1742        if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
1743                clear_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags);
1744                spin_unlock(&inode->i_lock);
1745                wake_up_bit(&nfsi->flags, NFS_INO_LAYOUTCOMMITTING);
1746                goto out_free;
1747        }
1748
1749        pnfs_list_write_lseg(inode, &data->lseg_list);
1750
1751        end_pos = nfsi->layout->plh_lwb;
1752        nfsi->layout->plh_lwb = 0;
1753
1754        nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
1755        spin_unlock(&inode->i_lock);
1756
1757        data->args.inode = inode;
1758        data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
1759        nfs_fattr_init(&data->fattr);
1760        data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
1761        data->res.fattr = &data->fattr;
1762        data->args.lastbytewritten = end_pos - 1;
1763        data->res.server = NFS_SERVER(inode);
1764
1765        status = nfs4_proc_layoutcommit(data, sync);
1766out:
1767        if (status)
1768                mark_inode_dirty_sync(inode);
1769        dprintk("<-- %s status %d\n", __func__, status);
1770        return status;
1771out_free:
1772        kfree(data);
1773        goto out;
1774}
1775
1776struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
1777{
1778        struct nfs4_threshold *thp;
1779
1780        thp = kzalloc(sizeof(*thp), GFP_NOFS);
1781        if (!thp) {
1782                dprintk("%s mdsthreshold allocation failed\n", __func__);
1783                return NULL;
1784        }
1785        return thp;
1786}
1787
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