lustre/osd-zfs/osd_io.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2017, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  *
  31  * lustre/osd-zfs/osd_io.c
  32  *
  33  * Author: Alex Zhuravlev <bzzz@whamcloud.com>
  34  * Author: Mike Pershin <tappro@whamcloud.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_OSD
  38
  39 #include <libcfs/libcfs.h>
  40 #include <obd_support.h>
  41 #include <lustre_net.h>
  42 #include <obd.h>
  43 #include <obd_class.h>
  44 #include <lustre_disk.h>
  45 #include <lustre_fid.h>
  46 #include <lustre_quota.h>
  47
  48 #include "osd_internal.h"
  49
  50 #include <sys/dnode.h>
  51 #include <sys/dbuf.h>
  52 #include <sys/spa.h>
  53 #include <sys/stat.h>
  54 #include <sys/zap.h>
  55 #include <sys/spa_impl.h>
  56 #include <sys/zfs_znode.h>
  57 #include <sys/dmu_tx.h>
  58 #include <sys/dmu_objset.h>
  59 #include <sys/dsl_prop.h>
  60 #include <sys/sa_impl.h>
  61 #include <sys/txg.h>
  62
  63 static char osd_0copy_tag[] = "zerocopy";
  64
  65 static void dbuf_set_pending_evict(dmu_buf_t *db)
  66 {
  67         dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
  68         dbi->db_pending_evict = TRUE;
  69 }
  70
  71 static void record_start_io(struct osd_device *osd, int rw, int discont_pages)
  72 {
  73         struct obd_histogram *h = osd->od_brw_stats.hist;
  74
  75         if (rw == READ) {
  76                 atomic_inc(&osd->od_r_in_flight);
  77                 lprocfs_oh_tally(&h[BRW_R_RPC_HIST],
  78                                  atomic_read(&osd->od_r_in_flight));
  79                 lprocfs_oh_tally(&h[BRW_R_DISCONT_PAGES], discont_pages);
  80
  81         } else {
  82                 atomic_inc(&osd->od_w_in_flight);
  83                 lprocfs_oh_tally(&h[BRW_W_RPC_HIST],
  84                                  atomic_read(&osd->od_w_in_flight));
  85                 lprocfs_oh_tally(&h[BRW_W_DISCONT_PAGES], discont_pages);
  86
  87         }
  88 }
  89
  90 static void record_end_io(struct osd_device *osd, int rw,
  91                           unsigned long elapsed, int disksize, int npages)
  92 {
  93         struct obd_histogram *h = osd->od_brw_stats.hist;
  94
  95         if (rw == READ)
  96                 atomic_dec(&osd->od_r_in_flight);
  97         else
  98                 atomic_dec(&osd->od_w_in_flight);
  99
 100         lprocfs_oh_tally_log2(&h[BRW_R_PAGES + rw], npages);
 101         if (disksize > 0)
 102                 lprocfs_oh_tally_log2(&h[BRW_R_DISK_IOSIZE + rw], disksize);
 103         if (elapsed)
 104                 lprocfs_oh_tally_log2(&h[BRW_R_IO_TIME + rw], elapsed);
 105 }
 106
 107 static ssize_t __osd_read(const struct lu_env *env, struct dt_object *dt,
 108                           struct lu_buf *buf, loff_t *pos, size_t *size)
 109 {
 110         struct osd_object *obj = osd_dt_obj(dt);
 111         uint64_t old_size;
 112         int rc;
 113
 114         LASSERT(dt_object_exists(dt));
 115         LASSERT(obj->oo_dn);
 116
 117         read_lock(&obj->oo_attr_lock);
 118         old_size = obj->oo_attr.la_size;
 119         read_unlock(&obj->oo_attr_lock);
 120
 121         if (*pos + *size > old_size) {
 122                 if (old_size < *pos)
 123                         return 0;
 124
 125                 *size = old_size - *pos;
 126         }
 127
 128         rc = osd_dmu_read(osd_obj2dev(obj), obj->oo_dn, *pos, *size,
 129                           buf->lb_buf, DMU_READ_PREFETCH);
 130         if (!rc) {
 131                 rc = *size;
 132                 *pos += *size;
 133         }
 134
 135         return rc;
 136 }
 137
 138 static ssize_t osd_read(const struct lu_env *env, struct dt_object *dt,
 139                         struct lu_buf *buf, loff_t *pos)
 140 {
 141         struct osd_device *osd = osd_obj2dev(osd_dt_obj(dt));
 142         size_t size = buf->lb_len;
 143         hrtime_t start = gethrtime();
 144         s64 delta_ms;
 145         int rc;
 146
 147         record_start_io(osd, READ, 0);
 148         rc = __osd_read(env, dt, buf, pos, &size);
 149         delta_ms = gethrtime() - start;
 150         do_div(delta_ms, NSEC_PER_MSEC);
 151         record_end_io(osd, READ, delta_ms, size, size >> PAGE_SHIFT);
 152
 153         return rc;
 154 }
 155
 156 static inline ssize_t osd_read_no_record(const struct lu_env *env,
 157                                          struct dt_object *dt,
 158                                          struct lu_buf *buf, loff_t *pos)
 159 {
 160         size_t size = buf->lb_len;
 161
 162         return __osd_read(env, dt, buf, pos, &size);
 163 }
 164
 165 static ssize_t osd_declare_write(const struct lu_env *env, struct dt_object *dt,
 166                                 const struct lu_buf *buf, loff_t pos,
 167                                 struct thandle *th)
 168 {
 169         struct osd_object  *obj  = osd_dt_obj(dt);
 170         struct osd_device  *osd = osd_obj2dev(obj);
 171         struct osd_thandle *oh;
 172         uint64_t            oid;
 173         ENTRY;
 174
 175         oh = container_of(th, struct osd_thandle, ot_super);
 176
 177         /* in some cases declare can race with creation (e.g. llog)
 178          * and we need to wait till object is initialized. notice
 179          * LOHA_EXISTs is supposed to be the last step in the
 180          * initialization */
 181
 182         /* size change (in dnode) will be declared by dmu_tx_hold_write() */
 183         if (dt_object_exists(dt))
 184                 oid = obj->oo_dn->dn_object;
 185         else
 186                 oid = DMU_NEW_OBJECT;
 187
 188         /* XXX: we still miss for append declaration support in ZFS
 189          *      -1 means append which is used by llog mostly, llog
 190          *      can grow upto LLOG_MIN_CHUNK_SIZE*8 records */
 191         if (pos == -1)
 192                 pos = max_t(loff_t, 256 * 8 * LLOG_MIN_CHUNK_SIZE,
 193                             obj->oo_attr.la_size + (2 << 20));
 194         osd_tx_hold_write(oh->ot_tx, oid, obj->oo_dn, pos, buf->lb_len);
 195
 196         /* dt_declare_write() is usually called for system objects, such
 197          * as llog or last_rcvd files. We needn't enforce quota on those
 198          * objects, so always set the lqi_space as 0. */
 199         RETURN(osd_declare_quota(env, osd, obj->oo_attr.la_uid,
 200                                  obj->oo_attr.la_gid, obj->oo_attr.la_projid,
 201                                  0, oh, NULL, OSD_QID_BLK));
 202 }
 203
 204 static ssize_t osd_write(const struct lu_env *env, struct dt_object *dt,
 205                         const struct lu_buf *buf, loff_t *pos,
 206                          struct thandle *th)
 207 {
 208         struct osd_object  *obj  = osd_dt_obj(dt);
 209         struct osd_device  *osd = osd_obj2dev(obj);
 210         struct osd_thandle *oh;
 211         uint64_t            offset = *pos;
 212         int                 rc;
 213
 214         ENTRY;
 215
 216         LASSERT(dt_object_exists(dt));
 217         LASSERT(obj->oo_dn);
 218
 219         LASSERT(th != NULL);
 220         oh = container_of(th, struct osd_thandle, ot_super);
 221
 222         osd_dmu_write(osd, obj->oo_dn, offset, (uint64_t)buf->lb_len,
 223                       buf->lb_buf, oh->ot_tx);
 224         write_lock(&obj->oo_attr_lock);
 225         if (obj->oo_attr.la_size < offset + buf->lb_len) {
 226                 obj->oo_attr.la_size = offset + buf->lb_len;
 227                 write_unlock(&obj->oo_attr_lock);
 228                 /* osd_object_sa_update() will be copying directly from oo_attr
 229                  * into dbuf.  any update within a single txg will copy the
 230                  * most actual */
 231                 rc = osd_object_sa_update(obj, SA_ZPL_SIZE(osd),
 232                                         &obj->oo_attr.la_size, 8, oh);
 233                 if (unlikely(rc))
 234                         GOTO(out, rc);
 235         } else {
 236                 write_unlock(&obj->oo_attr_lock);
 237         }
 238
 239         *pos += buf->lb_len;
 240         rc = buf->lb_len;
 241
 242 out:
 243         RETURN(rc);
 244 }
 245
 246 /*
 247  * XXX: for the moment I don't want to use lnb_flags for osd-internal
 248  *      purposes as it's not very well defined ...
 249  *      instead I use the lowest bit of the address so that:
 250  *        arc buffer:  .lnb_data = abuf          (arc we loan for write)
 251  *        dbuf buffer: .lnb_data = dbuf | 1      (dbuf we get for read)
 252  *        copy buffer: .lnb_page->mapping = obj (page we allocate for write)
 253  *
 254  *      bzzz, to blame
 255  */
 256 static int osd_bufs_put(const struct lu_env *env, struct dt_object *dt,
 257                         struct niobuf_local *lnb, int npages)
 258 {
 259         struct osd_object *obj  = osd_dt_obj(dt);
 260         struct osd_device *osd = osd_obj2dev(obj);
 261         unsigned long      ptr;
 262         int                i;
 263
 264         LASSERT(dt_object_exists(dt));
 265         LASSERT(obj->oo_dn);
 266
 267         for (i = 0; i < npages; i++) {
 268                 if (lnb[i].lnb_page == NULL)
 269                         continue;
 270                 if (lnb[i].lnb_page->mapping == (void *)obj) {
 271                         /* this is anonymous page allocated for copy-write */
 272                         lnb[i].lnb_page->mapping = NULL;
 273                         __free_page(lnb[i].lnb_page);
 274                         atomic_dec(&osd->od_zerocopy_alloc);
 275                 } else {
 276                         /* see comment in osd_bufs_get_read() */
 277                         ptr = (unsigned long)lnb[i].lnb_data;
 278                         if (ptr & 1UL) {
 279                                 ptr &= ~1UL;
 280                                 dmu_buf_rele((void *)ptr, osd_0copy_tag);
 281                                 atomic_dec(&osd->od_zerocopy_pin);
 282                         } else if (lnb[i].lnb_data != NULL) {
 283                                 int j, apages, abufsz;
 284                                 abufsz = arc_buf_size(lnb[i].lnb_data);
 285                                 apages = abufsz >> PAGE_SHIFT;
 286                                 /* these references to pages must be invalidated
 287                                  * to prevent access in osd_bufs_put() */
 288                                 for (j = 0; j < apages; j++)
 289                                         lnb[i + j].lnb_page = NULL;
 290                                 dmu_return_arcbuf(lnb[i].lnb_data);
 291                                 atomic_dec(&osd->od_zerocopy_loan);
 292                         }
 293                 }
 294                 lnb[i].lnb_page = NULL;
 295                 lnb[i].lnb_data = NULL;
 296         }
 297
 298         return 0;
 299 }
 300
 301 static inline struct page *kmem_to_page(void *addr)
 302 {
 303         LASSERT(!((unsigned long)addr & ~PAGE_MASK));
 304         if (is_vmalloc_addr(addr))
 305                 return vmalloc_to_page(addr);
 306         else
 307                 return virt_to_page(addr);
 308 }
 309
 310 /**
 311  * Prepare buffers for read.
 312  *
 313  * The function maps the range described by \a off and \a len to \a lnb array.
 314  * dmu_buf_hold_array_by_bonus() finds/creates appropriate ARC buffers, then
 315  * we fill \a lnb array with the pages storing ARC buffers. Notice the current
 316  * implementationt passes TRUE to dmu_buf_hold_array_by_bonus() to fill ARC
 317  * buffers with actual data, I/O is done in the conext of osd_bufs_get_read().
 318  * A better implementation would just return the buffers (potentially unfilled)
 319  * and subsequent osd_read_prep() would do I/O for many ranges concurrently.
 320  *
 321  * \param[in] env       environment
 322  * \param[in] obj       object
 323  * \param[in] off       offset in bytes
 324  * \param[in] len       the number of bytes to access
 325  * \param[out] lnb      array of local niobufs pointing to the buffers with data
 326  *
 327  * \retval              0 for success
 328  * \retval              negative error number of failure
 329  */
 330 static int osd_bufs_get_read(const struct lu_env *env, struct osd_object *obj,
 331                              loff_t off, ssize_t len, struct niobuf_local *lnb,
 332                              int maxlnb)
 333 {
 334         struct osd_device *osd = osd_obj2dev(obj);
 335         int rc, i, numbufs, npages = 0, drop_cache = 0;
 336         hrtime_t start = gethrtime();
 337         dmu_buf_t **dbp;
 338         s64 delta_ms;
 339
 340         ENTRY;
 341         record_start_io(osd, READ, 0);
 342
 343         if (obj->oo_attr.la_size >= osd->od_readcache_max_filesize)
 344                 drop_cache = 1;
 345
 346         /* grab buffers for read:
 347          * OSD API let us to grab buffers first, then initiate IO(s)
 348          * so that all required IOs will be done in parallel, but at the
 349          * moment DMU doesn't provide us with a method to grab buffers.
 350          * If we discover this is a vital for good performance we
 351          * can get own replacement for dmu_buf_hold_array_by_bonus().
 352          */
 353         while (len > 0 &&
 354                (obj->oo_dn->dn_datablkshift != 0 ||
 355                 off < obj->oo_dn->dn_datablksz)) {
 356                 if (obj->oo_dn->dn_datablkshift == 0 &&
 357                     off + len > obj->oo_dn->dn_datablksz)
 358                         len = obj->oo_dn->dn_datablksz - off;
 359
 360                 dbp = NULL;
 361                 if (unlikely(npages >= maxlnb))
 362                         GOTO(err, rc = -EOVERFLOW);
 363
 364                 rc = -dmu_buf_hold_array_by_bonus(&obj->oo_dn->dn_bonus->db,
 365                                                   off, len, TRUE, osd_0copy_tag,
 366                                                   &numbufs, &dbp);
 367                 if (unlikely(rc))
 368                         GOTO(err, rc);
 369
 370                 for (i = 0; i < numbufs; i++) {
 371                         int bufoff, tocpy, thispage;
 372                         void *dbf = dbp[i];
 373
 374                         LASSERT(len > 0);
 375
 376                         atomic_inc(&osd->od_zerocopy_pin);
 377
 378                         bufoff = off - dbp[i]->db_offset;
 379                         tocpy = min_t(int, dbp[i]->db_size - bufoff, len);
 380
 381                         /* kind of trick to differentiate dbuf vs. arcbuf */
 382                         LASSERT(((unsigned long)dbp[i] & 1) == 0);
 383                         dbf = (void *) ((unsigned long)dbp[i] | 1);
 384
 385                         while (tocpy > 0) {
 386                                 if (unlikely(npages >= maxlnb))
 387                                         GOTO(err, rc = -EOVERFLOW);
 388
 389                                 thispage = PAGE_SIZE;
 390                                 thispage -= bufoff & (PAGE_SIZE - 1);
 391                                 thispage = min(tocpy, thispage);
 392
 393                                 lnb->lnb_rc = 0;
 394                                 lnb->lnb_file_offset = off;
 395                                 lnb->lnb_page_offset = bufoff & ~PAGE_MASK;
 396                                 lnb->lnb_len = thispage;
 397                                 lnb->lnb_page = kmem_to_page(dbp[i]->db_data +
 398                                                              bufoff);
 399                                 /* mark just a single slot: we need this
 400                                  * reference to dbuf to be released once */
 401                                 lnb->lnb_data = dbf;
 402                                 dbf = NULL;
 403
 404                                 tocpy -= thispage;
 405                                 len -= thispage;
 406                                 bufoff += thispage;
 407                                 off += thispage;
 408
 409                                 npages++;
 410                                 lnb++;
 411                         }
 412
 413                         if (drop_cache)
 414                                 dbuf_set_pending_evict(dbp[i]);
 415
 416                         /* steal dbuf so dmu_buf_rele_array() can't release
 417                          * it */
 418                         dbp[i] = NULL;
 419                 }
 420
 421                 dmu_buf_rele_array(dbp, numbufs, osd_0copy_tag);
 422         }
 423
 424         delta_ms = gethrtime() - start;
 425         do_div(delta_ms, NSEC_PER_MSEC);
 426         record_end_io(osd, READ, delta_ms, npages * PAGE_SIZE, npages);
 427
 428         RETURN(npages);
 429
 430 err:
 431         LASSERT(rc < 0);
 432         if (dbp)
 433                 dmu_buf_rele_array(dbp, numbufs, osd_0copy_tag);
 434         osd_bufs_put(env, &obj->oo_dt, lnb - npages, npages);
 435         RETURN(rc);
 436 }
 437
 438 static inline arc_buf_t *osd_request_arcbuf(dnode_t *dn, size_t bs)
 439 {
 440         arc_buf_t *abuf;
 441
 442         abuf = dmu_request_arcbuf(&dn->dn_bonus->db, bs);
 443         if (unlikely(!abuf))
 444                 return ERR_PTR(-ENOMEM);
 445
 446 #if ZFS_VERSION_CODE < OBD_OCD_VERSION(0, 7, 0, 0)
 447         /**
 448          * ZFS prior to 0.7.0 doesn't guarantee PAGE_SIZE alignment for zio
 449          * blocks smaller than (PAGE_SIZE << 2). This poses a problem of
 450          * setting up page array for RDMA transfer. See LU-9305.
 451          */
 452         if ((unsigned long)abuf->b_data & ~PAGE_MASK) {
 453                 dmu_return_arcbuf(abuf);
 454                 return NULL;
 455         }
 456 #endif
 457
 458         return abuf;
 459 }
 460
 461 static int osd_bufs_get_write(const struct lu_env *env, struct osd_object *obj,
 462                               loff_t off, ssize_t len, struct niobuf_local *lnb,
 463                               int maxlnb)
 464 {
 465         struct osd_device *osd = osd_obj2dev(obj);
 466         int                poff, plen, off_in_block, sz_in_block;
 467         int                rc, i = 0, npages = 0;
 468         dnode_t *dn = obj->oo_dn;
 469         arc_buf_t *abuf;
 470         uint32_t bs = dn->dn_datablksz;
 471         ENTRY;
 472
 473         /*
 474          * currently only full blocks are subject to zerocopy approach:
 475          * so that we're sure nobody is trying to update the same block
 476          */
 477         while (len > 0) {
 478                 if (unlikely(npages >= maxlnb))
 479                         GOTO(out_err, rc = -EOVERFLOW);
 480
 481                 off_in_block = off & (bs - 1);
 482                 sz_in_block = min_t(int, bs - off_in_block, len);
 483
 484                 abuf = NULL;
 485                 if (sz_in_block == bs) {
 486                         /* full block, try to use zerocopy */
 487                         abuf = osd_request_arcbuf(dn, bs);
 488                         if (unlikely(IS_ERR(abuf)))
 489                                 GOTO(out_err, rc = PTR_ERR(abuf));
 490                 }
 491
 492                 if (abuf != NULL) {
 493                         atomic_inc(&osd->od_zerocopy_loan);
 494
 495                         /* go over pages arcbuf contains, put them as
 496                          * local niobufs for ptlrpc's bulks */
 497                         while (sz_in_block > 0) {
 498                                 plen = min_t(int, sz_in_block, PAGE_SIZE);
 499
 500                                 if (unlikely(npages >= maxlnb))
 501                                         GOTO(out_err, rc = -EOVERFLOW);
 502
 503                                 lnb[i].lnb_file_offset = off;
 504                                 lnb[i].lnb_page_offset = 0;
 505                                 lnb[i].lnb_len = plen;
 506                                 lnb[i].lnb_rc = 0;
 507                                 if (sz_in_block == bs)
 508                                         lnb[i].lnb_data = abuf;
 509                                 else
 510                                         lnb[i].lnb_data = NULL;
 511
 512                                 /* this one is not supposed to fail */
 513                                 lnb[i].lnb_page = kmem_to_page(abuf->b_data +
 514                                                         off_in_block);
 515                                 LASSERT(lnb[i].lnb_page);
 516
 517                                 lprocfs_counter_add(osd->od_stats,
 518                                                 LPROC_OSD_ZEROCOPY_IO, 1);
 519
 520                                 sz_in_block -= plen;
 521                                 len -= plen;
 522                                 off += plen;
 523                                 off_in_block += plen;
 524                                 i++;
 525                                 npages++;
 526                         }
 527                 } else {
 528                         if (off_in_block == 0 && len < bs &&
 529                                         off + len >= obj->oo_attr.la_size)
 530                                 lprocfs_counter_add(osd->od_stats,
 531                                                 LPROC_OSD_TAIL_IO, 1);
 532
 533                         /* can't use zerocopy, allocate temp. buffers */
 534                         poff = off & (PAGE_SIZE - 1);
 535                         while (sz_in_block > 0) {
 536                                 plen = min_t(int, poff + sz_in_block,
 537                                              PAGE_SIZE);
 538                                 plen -= poff;
 539
 540                                 if (unlikely(npages >= maxlnb))
 541                                         GOTO(out_err, rc = -EOVERFLOW);
 542
 543                                 lnb[i].lnb_file_offset = off;
 544                                 lnb[i].lnb_page_offset = poff;
 545                                 poff = 0;
 546
 547                                 lnb[i].lnb_len = plen;
 548                                 lnb[i].lnb_rc = 0;
 549                                 lnb[i].lnb_data = NULL;
 550
 551                                 lnb[i].lnb_page = alloc_page(OSD_GFP_IO);
 552                                 if (unlikely(lnb[i].lnb_page == NULL))
 553                                         GOTO(out_err, rc = -ENOMEM);
 554
 555                                 LASSERT(lnb[i].lnb_page->mapping == NULL);
 556                                 lnb[i].lnb_page->mapping = (void *)obj;
 557
 558                                 atomic_inc(&osd->od_zerocopy_alloc);
 559                                 lprocfs_counter_add(osd->od_stats,
 560                                                 LPROC_OSD_COPY_IO, 1);
 561
 562                                 sz_in_block -= plen;
 563                                 len -= plen;
 564                                 off += plen;
 565                                 i++;
 566                                 npages++;
 567                         }
 568                 }
 569         }
 570
 571         RETURN(npages);
 572
 573 out_err:
 574         osd_bufs_put(env, &obj->oo_dt, lnb, npages);
 575         RETURN(rc);
 576 }
 577
 578 static int osd_bufs_get(const struct lu_env *env, struct dt_object *dt,
 579                         loff_t offset, ssize_t len, struct niobuf_local *lnb,
 580                         int maxlnb, enum dt_bufs_type rw)
 581 {
 582         struct osd_object *obj  = osd_dt_obj(dt);
 583         int                rc;
 584
 585         LASSERT(dt_object_exists(dt));
 586         LASSERT(obj->oo_dn);
 587
 588         if (rw & DT_BUFS_TYPE_WRITE)
 589                 rc = osd_bufs_get_write(env, obj, offset, len, lnb, maxlnb);
 590         else
 591                 rc = osd_bufs_get_read(env, obj, offset, len, lnb, maxlnb);
 592
 593         return rc;
 594 }
 595
 596 static int osd_write_prep(const struct lu_env *env, struct dt_object *dt,
 597                         struct niobuf_local *lnb, int npages)
 598 {
 599         struct osd_object *obj = osd_dt_obj(dt);
 600
 601         LASSERT(dt_object_exists(dt));
 602         LASSERT(obj->oo_dn);
 603
 604         return 0;
 605 }
 606
 607 static inline uint64_t osd_roundup2blocksz(uint64_t size,
 608                                            uint64_t offset,
 609                                            uint32_t blksz)
 610 {
 611         LASSERT(blksz > 0);
 612
 613         size += offset % blksz;
 614
 615         if (likely(is_power_of_2(blksz)))
 616                 return round_up(size, blksz);
 617         else
 618                 return DIV_ROUND_UP_ULL(size, blksz) * blksz;
 619 }
 620
 621 static int osd_declare_write_commit(const struct lu_env *env,
 622                                     struct dt_object *dt,
 623                                     struct niobuf_local *lnb, int npages,
 624                                     struct thandle *th)
 625 {
 626         struct osd_object  *obj = osd_dt_obj(dt);
 627         struct osd_device  *osd = osd_obj2dev(obj);
 628         struct osd_thandle *oh;
 629         uint64_t            offset = 0;
 630         uint32_t            size = 0;
 631         uint32_t blksz = obj->oo_dn->dn_datablksz;
 632         int                 i, rc;
 633         bool synced = false;
 634         long long           space = 0;
 635         struct page        *last_page = NULL;
 636         unsigned long       discont_pages = 0;
 637         enum osd_quota_local_flags local_flags = 0;
 638         enum osd_qid_declare_flags declare_flags = OSD_QID_BLK;
 639         ENTRY;
 640
 641         LASSERT(dt_object_exists(dt));
 642         LASSERT(obj->oo_dn);
 643
 644         LASSERT(lnb);
 645         LASSERT(npages > 0);
 646
 647         oh = container_of(th, struct osd_thandle, ot_super);
 648
 649         for (i = 0; i < npages; i++) {
 650                 if (last_page && lnb[i].lnb_page->index != (last_page->index + 1))
 651                         ++discont_pages;
 652                 last_page = lnb[i].lnb_page;
 653                 if (lnb[i].lnb_rc)
 654                         /* ENOSPC, network RPC error, etc.
 655                          * We don't want to book space for pages which will be
 656                          * skipped in osd_write_commit(). Hence we skip pages
 657                          * with lnb_rc != 0 here too */
 658                         continue;
 659                 /* ignore quota for the whole request if any page is from
 660                  * client cache or written by root.
 661                  *
 662                  * XXX once we drop the 1.8 client support, the checking
 663                  * for whether page is from cache can be simplified as:
 664                  * !(lnb[i].flags & OBD_BRW_SYNC)
 665                  *
 666                  * XXX we could handle this on per-lnb basis as done by
 667                  * grant. */
 668                 if ((lnb[i].lnb_flags & OBD_BRW_NOQUOTA) ||
 669                     (lnb[i].lnb_flags & (OBD_BRW_FROM_GRANT | OBD_BRW_SYNC)) ==
 670                     OBD_BRW_FROM_GRANT)
 671                         declare_flags |= OSD_QID_FORCE;
 672
 673                 if (size == 0) {
 674                         /* first valid lnb */
 675                         offset = lnb[i].lnb_file_offset;
 676                         size = lnb[i].lnb_len;
 677                         continue;
 678                 }
 679                 if (offset + size == lnb[i].lnb_file_offset) {
 680                         /* this lnb is contiguous to the previous one */
 681                         size += lnb[i].lnb_len;
 682                         continue;
 683                 }
 684
 685                 osd_tx_hold_write(oh->ot_tx, obj->oo_dn->dn_object,
 686                                   obj->oo_dn, offset, size);
 687                 /* Estimating space to be consumed by a write is rather
 688                  * complicated with ZFS. As a consequence, we don't account for
 689                  * indirect blocks and just use as a rough estimate the worse
 690                  * case where the old space is being held by a snapshot. Quota
 691                  * overrun will be adjusted once the operation is committed, if
 692                  * required. */
 693                 space += osd_roundup2blocksz(size, offset, blksz);
 694
 695                 offset = lnb[i].lnb_file_offset;
 696                 size = lnb[i].lnb_len;
 697         }
 698
 699         if (size) {
 700                 osd_tx_hold_write(oh->ot_tx, obj->oo_dn->dn_object, obj->oo_dn,
 701                                   offset, size);
 702                 space += osd_roundup2blocksz(size, offset, blksz);
 703         }
 704
 705         /* backend zfs filesystem might be configured to store multiple data
 706          * copies */
 707         space  *= osd->od_os->os_copies;
 708         space   = toqb(space);
 709         CDEBUG(D_QUOTA, "writing %d pages, reserving %lldK of quota space\n",
 710                npages, space);
 711
 712         record_start_io(osd, WRITE, discont_pages);
 713 retry:
 714         /* acquire quota space if needed */
 715         rc = osd_declare_quota(env, osd, obj->oo_attr.la_uid,
 716                                obj->oo_attr.la_gid, obj->oo_attr.la_projid,
 717                                space, oh, &local_flags, declare_flags);
 718
 719         if (!synced && rc == -EDQUOT &&
 720             (local_flags & QUOTA_FL_SYNC) != 0) {
 721                 dt_sync(env, th->th_dev);
 722                 synced = true;
 723                 CDEBUG(D_QUOTA, "retry after sync\n");
 724                 local_flags = 0;
 725                 goto retry;
 726         }
 727
 728         /* we need only to store the overquota flags in the first lnb for
 729          * now, once we support multiple objects BRW, this code needs be
 730          * revised. */
 731         if (local_flags & QUOTA_FL_OVER_USRQUOTA)
 732                 lnb[0].lnb_flags |= OBD_BRW_OVER_USRQUOTA;
 733         if (local_flags & QUOTA_FL_OVER_GRPQUOTA)
 734                 lnb[0].lnb_flags |= OBD_BRW_OVER_GRPQUOTA;
 735 #ifdef ZFS_PROJINHERIT
 736         if (local_flags & QUOTA_FL_OVER_PRJQUOTA)
 737                 lnb[0].lnb_flags |= OBD_BRW_OVER_PRJQUOTA;
 738 #endif
 739
 740         RETURN(rc);
 741 }
 742
 743 /**
 744  * Policy to grow ZFS block size by write pattern.
 745  * For sequential write, it grows block size gradually until it reaches the
 746  * maximum blocksize the dataset can support. Otherwise, it will pick a
 747  * a block size by the writing region of this I/O.
 748  */
 749 static int osd_grow_blocksize(struct osd_object *obj, struct osd_thandle *oh,
 750                               uint64_t start, uint64_t end)
 751 {
 752         struct osd_device       *osd = osd_obj2dev(obj);
 753         dnode_t *dn = obj->oo_dn;
 754         uint32_t                 blksz;
 755         int                      rc = 0;
 756
 757         ENTRY;
 758
 759         if (dn->dn_maxblkid > 0) /* can't change block size */
 760                 GOTO(out, rc);
 761
 762         if (dn->dn_datablksz >= osd->od_max_blksz)
 763                 GOTO(out, rc);
 764
 765         down_write(&obj->oo_guard);
 766
 767         blksz = dn->dn_datablksz;
 768         if (blksz >= osd->od_max_blksz) /* check again after grabbing lock */
 769                 GOTO(out_unlock, rc);
 770
 771         /* now ZFS can support up to 16MB block size, and if the write
 772          * is sequential, it just increases the block size gradually */
 773         if (start <= blksz) { /* sequential */
 774                 blksz = (uint32_t)min_t(uint64_t, osd->od_max_blksz, end);
 775         } else { /* sparse, pick a block size by write region */
 776                 blksz = (uint32_t)min_t(uint64_t, osd->od_max_blksz,
 777                                         end - start);
 778         }
 779
 780         if (!is_power_of_2(blksz))
 781                 blksz = size_roundup_power2(blksz);
 782
 783         if (blksz > dn->dn_datablksz) {
 784                 rc = -dmu_object_set_blocksize(osd->od_os, dn->dn_object,
 785                                                blksz, 0, oh->ot_tx);
 786                 LASSERT(ergo(rc == 0, dn->dn_datablksz >= blksz));
 787                 if (rc < 0)
 788                         CDEBUG(D_INODE, "object "DFID": change block size"
 789                                "%u -> %u error rc = %d\n",
 790                                PFID(lu_object_fid(&obj->oo_dt.do_lu)),
 791                                dn->dn_datablksz, blksz, rc);
 792         }
 793         EXIT;
 794 out_unlock:
 795         up_write(&obj->oo_guard);
 796 out:
 797         return rc;
 798 }
 799
 800 static void osd_evict_dbufs_after_write(struct osd_object *obj,
 801                                         loff_t off, ssize_t len)
 802 {
 803         dmu_buf_t **dbp;
 804         int i, rc, numbufs;
 805
 806         rc = -dmu_buf_hold_array_by_bonus(&obj->oo_dn->dn_bonus->db, off, len,
 807                                           TRUE, osd_0copy_tag, &numbufs, &dbp);
 808         if (unlikely(rc))
 809                 return;
 810
 811         for (i = 0; i < numbufs; i++)
 812                 dbuf_set_pending_evict(dbp[i]);
 813
 814         dmu_buf_rele_array(dbp, numbufs, osd_0copy_tag);
 815 }
 816
 817 static int osd_write_commit(const struct lu_env *env, struct dt_object *dt,
 818                         struct niobuf_local *lnb, int npages,
 819                         struct thandle *th, __u64 user_size)
 820 {
 821         struct osd_object  *obj  = osd_dt_obj(dt);
 822         struct osd_device  *osd = osd_obj2dev(obj);
 823         struct osd_thandle *oh;
 824         uint64_t            new_size = 0;
 825         int                 i, abufsz, rc = 0, drop_cache = 0;
 826         unsigned long      iosize = 0;
 827         ENTRY;
 828
 829         LASSERT(dt_object_exists(dt));
 830         LASSERT(obj->oo_dn);
 831
 832         LASSERT(th != NULL);
 833         oh = container_of(th, struct osd_thandle, ot_super);
 834
 835         /* adjust block size. Assume the buffers are sorted. */
 836         (void)osd_grow_blocksize(obj, oh, lnb[0].lnb_file_offset,
 837                                  lnb[npages - 1].lnb_file_offset +
 838                                  lnb[npages - 1].lnb_len);
 839
 840         if (obj->oo_attr.la_size >= osd->od_readcache_max_filesize ||
 841             lnb[npages - 1].lnb_file_offset + lnb[npages - 1].lnb_len >=
 842             osd->od_readcache_max_filesize)
 843                 drop_cache = 1;
 844
 845         if (OBD_FAIL_CHECK(OBD_FAIL_OST_MAPBLK_ENOSPC))
 846                 RETURN(-ENOSPC);
 847
 848         /* if la_size is already bigger than specified user_size,
 849          * ignore user_size
 850          */
 851         if (obj->oo_attr.la_size > user_size)
 852                 user_size = 0;
 853
 854         /* LU-8791: take oo_guard to avoid the deadlock that changing block
 855          * size and assigning arcbuf take place at the same time.
 856          *
 857          * Thread 1:
 858          * osd_write_commit()
 859          *  -> osd_grow_blocksize() with osd_object::oo_guard held
 860          *   -> dmu_object_set_blocksize()
 861          *    -> dnode_set_blksz(), with dnode_t::dn_struct_rwlock
 862          *       write lock held
 863          *     -> dbuf_new_size()
 864          *      -> dmu_buf_will_dirty()
 865          *       -> dbuf_read()
 866          *        -> wait for the dbuf state to change
 867          * Thread 2:
 868          * osd_write_commit()
 869          *  -> dmu_assign_arcbuf()
 870          *   -> dbuf_assign_arcbuf(), set dbuf state to DB_FILL
 871          *    -> dbuf_dirty()
 872          *     -> try to hold the read lock of dnode_t::dn_struct_rwlock
 873          *
 874          * By taking the read lock, it can avoid thread 2 to enter into the
 875          * critical section of assigning the arcbuf, while thread 1 is
 876          * changing the block size.
 877          */
 878         down_read(&obj->oo_guard);
 879         for (i = 0; i < npages; i++) {
 880                 CDEBUG(D_INODE, "write %u bytes at %u\n",
 881                         (unsigned) lnb[i].lnb_len,
 882                         (unsigned) lnb[i].lnb_file_offset);
 883
 884                 if (lnb[i].lnb_rc) {
 885                         /* ENOSPC, network RPC error, etc.
 886                          * Unlike ldiskfs, zfs allocates new blocks on rewrite,
 887                          * so we skip this page if lnb_rc is set to -ENOSPC */
 888                         CDEBUG(D_INODE, "obj "DFID": skipping lnb[%u]: rc=%d\n",
 889                                 PFID(lu_object_fid(&dt->do_lu)), i,
 890                                 lnb[i].lnb_rc);
 891                         continue;
 892                 }
 893
 894                 if (new_size < lnb[i].lnb_file_offset + lnb[i].lnb_len)
 895                         new_size = lnb[i].lnb_file_offset + lnb[i].lnb_len;
 896                 if (lnb[i].lnb_page == NULL)
 897                         continue;
 898
 899                 if (lnb[i].lnb_page->mapping == (void *)obj) {
 900                         osd_dmu_write(osd, obj->oo_dn, lnb[i].lnb_file_offset,
 901                                       lnb[i].lnb_len, kmap(lnb[i].lnb_page) +
 902                                       lnb[i].lnb_page_offset, oh->ot_tx);
 903                         kunmap(lnb[i].lnb_page);
 904                         iosize += lnb[i].lnb_len;
 905                         abufsz = lnb[i].lnb_len; /* to drop cache below */
 906                 } else if (lnb[i].lnb_data) {
 907                         int j, apages;
 908                         LASSERT(((unsigned long)lnb[i].lnb_data & 1) == 0);
 909                         /* buffer loaned for zerocopy, try to use it.
 910                          * notice that dmu_assign_arcbuf() is smart
 911                          * enough to recognize changed blocksize
 912                          * in this case it fallbacks to dmu_write() */
 913                         abufsz = arc_buf_size(lnb[i].lnb_data);
 914                         LASSERT(abufsz & PAGE_MASK);
 915                         apages = abufsz >> PAGE_SHIFT;
 916                         LASSERT(i + apages <= npages);
 917                         /* these references to pages must be invalidated
 918                          * to prevent access in osd_bufs_put() */
 919                         for (j = 0; j < apages; j++)
 920                                 lnb[i + j].lnb_page = NULL;
 921                         dmu_assign_arcbuf(&obj->oo_dn->dn_bonus->db,
 922                                           lnb[i].lnb_file_offset,
 923                                           lnb[i].lnb_data, oh->ot_tx);
 924                         /* drop the reference, otherwise osd_put_bufs()
 925                          * will be releasing it - bad! */
 926                         lnb[i].lnb_data = NULL;
 927                         atomic_dec(&osd->od_zerocopy_loan);
 928                         iosize += abufsz;
 929                 } else {
 930                         /* we don't want to deal with cache if nothing
 931                          * has been send to ZFS at this step */
 932                         continue;
 933                 }
 934
 935                 if (!drop_cache)
 936                         continue;
 937
 938                 /* we have to mark dbufs for eviction here because
 939                  * dmu_assign_arcbuf() may create a new dbuf for
 940                  * loaned abuf */
 941                 osd_evict_dbufs_after_write(obj, lnb[i].lnb_file_offset,
 942                                             abufsz);
 943         }
 944         up_read(&obj->oo_guard);
 945
 946         if (unlikely(new_size == 0)) {
 947                 /* no pages to write, no transno is needed */
 948                 th->th_local = 1;
 949                 /* it is important to return 0 even when all lnb_rc == -ENOSPC
 950                  * since ofd_commitrw_write() retries several times on ENOSPC */
 951                 record_end_io(osd, WRITE, 0, 0, 0);
 952                 RETURN(0);
 953         }
 954
 955         /* if file has grown, take user_size into account */
 956         if (user_size && new_size > user_size)
 957                 new_size = user_size;
 958         write_lock(&obj->oo_attr_lock);
 959         if (obj->oo_attr.la_size < new_size) {
 960                 obj->oo_attr.la_size = new_size;
 961                 write_unlock(&obj->oo_attr_lock);
 962                 /* osd_object_sa_update() will be copying directly from
 963                  * oo_attr into dbuf. any update within a single txg will copy
 964                  * the most actual */
 965                 rc = osd_object_sa_update(obj, SA_ZPL_SIZE(osd),
 966                                           &obj->oo_attr.la_size, 8, oh);
 967         } else {
 968                 write_unlock(&obj->oo_attr_lock);
 969         }
 970
 971         record_end_io(osd, WRITE, 0, iosize, npages);
 972
 973         RETURN(rc);
 974 }
 975
 976 static int osd_read_prep(const struct lu_env *env, struct dt_object *dt,
 977                         struct niobuf_local *lnb, int npages)
 978 {
 979         struct osd_object *obj  = osd_dt_obj(dt);
 980         int                i;
 981         loff_t             eof;
 982
 983         LASSERT(dt_object_exists(dt));
 984         LASSERT(obj->oo_dn);
 985
 986         read_lock(&obj->oo_attr_lock);
 987         eof = obj->oo_attr.la_size;
 988         read_unlock(&obj->oo_attr_lock);
 989
 990         for (i = 0; i < npages; i++) {
 991                 if (unlikely(lnb[i].lnb_rc < 0))
 992                         continue;
 993
 994                 lnb[i].lnb_rc = lnb[i].lnb_len;
 995
 996                 if (lnb[i].lnb_file_offset + lnb[i].lnb_len >= eof) {
 997                         /* send complete pages all the time */
 998                         if (eof <= lnb[i].lnb_file_offset)
 999                                 lnb[i].lnb_rc = 0;
1000
1001                         /* all subsequent rc should be 0 */
1002                         while (++i < npages)
1003                                 lnb[i].lnb_rc = 0;
1004                         break;
1005                 }
1006         }
1007
1008         return 0;
1009 }
1010
1011 /*
1012  * Punch/truncate an object
1013  *
1014  *      IN:     db  - dmu_buf of the object to free data in.
1015  *              off - start of section to free.
1016  *              len - length of section to free (DMU_OBJECT_END => to EOF).
1017  *
1018  *      RETURN: 0 if success
1019  *              error code if failure
1020  *
1021  * The transaction passed to this routine must have
1022  * dmu_tx_hold_sa() and if off < size, dmu_tx_hold_free()
1023  * called and then assigned to a transaction group.
1024  */
1025 static int __osd_object_punch(struct osd_object *obj, objset_t *os,
1026                               dmu_tx_t *tx, uint64_t off, uint64_t len)
1027 {
1028         dnode_t *dn = obj->oo_dn;
1029         uint64_t size = obj->oo_attr.la_size;
1030         int rc = 0;
1031
1032         /* Assert that the transaction has been assigned to a
1033            transaction group. */
1034         LASSERT(tx->tx_txg != 0);
1035         /*
1036          * Nothing to do if file already at desired length.
1037          */
1038         if (len == DMU_OBJECT_END && size == off)
1039                 return 0;
1040
1041         /* if object holds encrypted content, we need to make sure we truncate
1042          * on an encryption unit boundary, or subsequent reads will get
1043          * corrupted content
1044          */
1045         if (len != DMU_OBJECT_END)
1046                 len -= LUSTRE_ENCRYPTION_UNIT_SIZE -
1047                         (off & ~LUSTRE_ENCRYPTION_MASK);
1048         if (obj->oo_lma_flags & LUSTRE_ENCRYPT_FL &&
1049             off & ~LUSTRE_ENCRYPTION_MASK)
1050                 off = (off & LUSTRE_ENCRYPTION_MASK) +
1051                         LUSTRE_ENCRYPTION_UNIT_SIZE;
1052
1053
1054         /* XXX: dnode_free_range() can be used to save on dnode lookup */
1055         if (off < size)
1056                 dmu_free_range(os, dn->dn_object, off, len, tx);
1057
1058         return rc;
1059 }
1060
1061 static int osd_punch(const struct lu_env *env, struct dt_object *dt,
1062                         __u64 start, __u64 end, struct thandle *th)
1063 {
1064         struct osd_object  *obj = osd_dt_obj(dt);
1065         struct osd_device  *osd = osd_obj2dev(obj);
1066         struct osd_thandle *oh;
1067         __u64               len;
1068         int                 rc = 0;
1069         ENTRY;
1070
1071         LASSERT(dt_object_exists(dt));
1072         LASSERT(osd_invariant(obj));
1073
1074         LASSERT(th != NULL);
1075         oh = container_of(th, struct osd_thandle, ot_super);
1076
1077         write_lock(&obj->oo_attr_lock);
1078         /* truncate */
1079         if (end == OBD_OBJECT_EOF || end >= obj->oo_attr.la_size)
1080                 len = DMU_OBJECT_END;
1081         else
1082                 len = end - start;
1083         write_unlock(&obj->oo_attr_lock);
1084
1085         rc = __osd_object_punch(obj, osd->od_os, oh->ot_tx, start, len);
1086
1087         /* set new size */
1088         if (len == DMU_OBJECT_END) {
1089                 write_lock(&obj->oo_attr_lock);
1090                 obj->oo_attr.la_size = start;
1091                 write_unlock(&obj->oo_attr_lock);
1092                 rc = osd_object_sa_update(obj, SA_ZPL_SIZE(osd),
1093                                           &obj->oo_attr.la_size, 8, oh);
1094         }
1095         RETURN(rc);
1096 }
1097
1098 static int osd_declare_punch(const struct lu_env *env, struct dt_object *dt,
1099                         __u64 start, __u64 end, struct thandle *handle)
1100 {
1101         struct osd_object  *obj = osd_dt_obj(dt);
1102         struct osd_device  *osd = osd_obj2dev(obj);
1103         struct osd_thandle *oh;
1104         __u64               len;
1105         ENTRY;
1106
1107         oh = container_of(handle, struct osd_thandle, ot_super);
1108
1109         read_lock(&obj->oo_attr_lock);
1110         if (end == OBD_OBJECT_EOF || end >= obj->oo_attr.la_size)
1111                 len = DMU_OBJECT_END;
1112         else
1113                 len = end - start;
1114
1115         /* declare we'll free some blocks ... */
1116         /* if object holds encrypted content, we need to make sure we truncate
1117          * on an encryption unit boundary, or subsequent reads will get
1118          * corrupted content
1119          */
1120         if (obj->oo_lma_flags & LUSTRE_ENCRYPT_FL &&
1121             start & ~LUSTRE_ENCRYPTION_MASK)
1122                 start = (start & LUSTRE_ENCRYPTION_MASK) +
1123                         LUSTRE_ENCRYPTION_UNIT_SIZE;
1124         if (start < obj->oo_attr.la_size) {
1125                 read_unlock(&obj->oo_attr_lock);
1126                 dmu_tx_mark_netfree(oh->ot_tx);
1127                 dmu_tx_hold_free(oh->ot_tx, obj->oo_dn->dn_object, start, len);
1128         } else {
1129                 read_unlock(&obj->oo_attr_lock);
1130         }
1131
1132         RETURN(osd_declare_quota(env, osd, obj->oo_attr.la_uid,
1133                                  obj->oo_attr.la_gid, obj->oo_attr.la_projid,
1134                                  0, oh, NULL, OSD_QID_BLK));
1135 }
1136
1137 static int osd_ladvise(const struct lu_env *env, struct dt_object *dt,
1138                        __u64 start, __u64 end, enum lu_ladvise_type advice)
1139 {
1140         int     rc;
1141         ENTRY;
1142
1143         switch (advice) {
1144         default:
1145                 rc = -ENOTSUPP;
1146                 break;
1147         }
1148
1149         RETURN(rc);
1150 }
1151
1152 static int osd_fallocate(const struct lu_env *env, struct dt_object *dt,
1153                          __u64 start, __u64 end, int mode, struct thandle *th)
1154 {
1155         int rc = -EOPNOTSUPP;
1156         ENTRY;
1157
1158          /*
1159           * space preallocation is not supported for ZFS
1160           * Returns -EOPNOTSUPP for now
1161           */
1162         RETURN(rc);
1163 }
1164
1165 static int osd_declare_fallocate(const struct lu_env *env,
1166                                  struct dt_object *dt, __u64 start, __u64 end,
1167                                  int mode, struct thandle *th)
1168 {
1169         int rc = -EOPNOTSUPP;
1170         ENTRY;
1171
1172          /*
1173           * space preallocation is not supported for ZFS
1174           * Returns -EOPNOTSUPP for now
1175           */
1176         RETURN(rc);
1177 }
1178
1179 static loff_t osd_lseek(const struct lu_env *env, struct dt_object *dt,
1180                         loff_t offset, int whence)
1181 {
1182         struct osd_object *obj = osd_dt_obj(dt);
1183         struct osd_device *osd = osd_obj2dev(obj);
1184         uint64_t size = obj->oo_attr.la_size;
1185         uint64_t result = offset;
1186         int rc;
1187         boolean_t hole = whence == SEEK_HOLE;
1188
1189         ENTRY;
1190
1191         LASSERT(dt_object_exists(dt));
1192         LASSERT(osd_invariant(obj));
1193         LASSERT(offset >= 0);
1194
1195         /* for SEEK_HOLE treat 'offset' beyond the end of file as in real
1196          * hole. LOV to decide after all if that real hole or not.
1197          */
1198         if (offset >= size)
1199                 RETURN(hole ? offset : -ENXIO);
1200
1201         /* Currently ZFS reports no valid DATA offset if object has dirty data
1202          * and we cannot just switch to generic way with reporting DATA on all
1203          * file offsets and HOLE beyond end of file, because we may get HOLE
1204          * reported correctly at some offset inside file then DATA will find
1205          * dirty state and be reported also at that offset by generic approach.
1206          * This is because for HOLE report ZFS doesn't check dirty state but
1207          * does for DATA.
1208          * The only way to get reliable results is to call txg_wait_synced()
1209          * when ZFS reports EBUSY result and repeat lseek call and that is
1210          * controlled via od_sync_on_lseek option.
1211          */
1212         if (!osd->od_sync_on_lseek)
1213                 result = hole ? size : offset;
1214
1215 again:
1216         rc = osd_dmu_offset_next(osd->od_os, obj->oo_dn->dn_object, hole,
1217                                  &result);
1218         /* dirty inode, lseek result is unreliable without sync */
1219         if (rc == EBUSY) {
1220                 txg_wait_synced(dmu_objset_pool(osd->od_os), 0ULL);
1221                 goto again;
1222         }
1223
1224         if (rc == ESRCH)
1225                 RETURN(-ENXIO);
1226
1227         /* ZFS is not exported all needed function, so fall back to the
1228          * generic logic: for HOLE return file size, for DATA return
1229          * the current offset
1230          */
1231         if (rc == EOPNOTSUPP)
1232                 result = hole ? size : offset;
1233         else if (rc)
1234                 return -rc;
1235
1236         /* dmu_offset_next() only works on whole blocks so may return SEEK_HOLE
1237          * result as end of the last block instead of logical EOF which we need
1238          */
1239         if (result > size)
1240                 result = size;
1241
1242         RETURN(result);
1243 }
1244
1245 const struct dt_body_operations osd_body_ops = {
1246         .dbo_read                       = osd_read,
1247         .dbo_declare_write              = osd_declare_write,
1248         .dbo_write                      = osd_write,
1249         .dbo_bufs_get                   = osd_bufs_get,
1250         .dbo_bufs_put                   = osd_bufs_put,
1251         .dbo_write_prep                 = osd_write_prep,
1252         .dbo_declare_write_commit       = osd_declare_write_commit,
1253         .dbo_write_commit               = osd_write_commit,
1254         .dbo_read_prep                  = osd_read_prep,
1255         .dbo_declare_punch              = osd_declare_punch,
1256         .dbo_punch                      = osd_punch,
1257         .dbo_ladvise                    = osd_ladvise,
1258         .dbo_declare_fallocate          = osd_declare_fallocate,
1259         .dbo_fallocate                  = osd_fallocate,
1260         .dbo_lseek                      = osd_lseek,
1261 };
1262
1263 const struct dt_body_operations osd_body_scrub_ops = {
1264         .dbo_read                       = osd_read_no_record,
1265         .dbo_declare_write              = osd_declare_write,
1266         .dbo_write                      = osd_write,
1267 };