linux/fs/nfs/blocklayout/extents.c
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   1/*
   2 *  linux/fs/nfs/blocklayout/blocklayout.h
   3 *
   4 *  Module for the NFSv4.1 pNFS block layout driver.
   5 *
   6 *  Copyright (c) 2006 The Regents of the University of Michigan.
   7 *  All rights reserved.
   8 *
   9 *  Andy Adamson <andros@citi.umich.edu>
  10 *  Fred Isaman <iisaman@umich.edu>
  11 *
  12 * permission is granted to use, copy, create derivative works and
  13 * redistribute this software and such derivative works for any purpose,
  14 * so long as the name of the university of michigan is not used in
  15 * any advertising or publicity pertaining to the use or distribution
  16 * of this software without specific, written prior authorization.  if
  17 * the above copyright notice or any other identification of the
  18 * university of michigan is included in any copy of any portion of
  19 * this software, then the disclaimer below must also be included.
  20 *
  21 * this software is provided as is, without representation from the
  22 * university of michigan as to its fitness for any purpose, and without
  23 * warranty by the university of michigan of any kind, either express
  24 * or implied, including without limitation the implied warranties of
  25 * merchantability and fitness for a particular purpose.  the regents
  26 * of the university of michigan shall not be liable for any damages,
  27 * including special, indirect, incidental, or consequential damages,
  28 * with respect to any claim arising out or in connection with the use
  29 * of the software, even if it has been or is hereafter advised of the
  30 * possibility of such damages.
  31 */
  32
  33#include "blocklayout.h"
  34#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  35
  36/* Bit numbers */
  37#define EXTENT_INITIALIZED 0
  38#define EXTENT_WRITTEN     1
  39#define EXTENT_IN_COMMIT   2
  40#define INTERNAL_EXISTS    MY_MAX_TAGS
  41#define INTERNAL_MASK      ((1 << INTERNAL_EXISTS) - 1)
  42
  43/* Returns largest t<=s s.t. t%base==0 */
  44static inline sector_t normalize(sector_t s, int base)
  45{
  46        sector_t tmp = s; /* Since do_div modifies its argument */
  47        return s - sector_div(tmp, base);
  48}
  49
  50static inline sector_t normalize_up(sector_t s, int base)
  51{
  52        return normalize(s + base - 1, base);
  53}
  54
  55/* Complete stub using list while determine API wanted */
  56
  57/* Returns tags, or negative */
  58static int32_t _find_entry(struct my_tree *tree, u64 s)
  59{
  60        struct pnfs_inval_tracking *pos;
  61
  62        dprintk("%s(%llu) enter\n", __func__, s);
  63        list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
  64                if (pos->it_sector > s)
  65                        continue;
  66                else if (pos->it_sector == s)
  67                        return pos->it_tags & INTERNAL_MASK;
  68                else
  69                        break;
  70        }
  71        return -ENOENT;
  72}
  73
  74static inline
  75int _has_tag(struct my_tree *tree, u64 s, int32_t tag)
  76{
  77        int32_t tags;
  78
  79        dprintk("%s(%llu, %i) enter\n", __func__, s, tag);
  80        s = normalize(s, tree->mtt_step_size);
  81        tags = _find_entry(tree, s);
  82        if ((tags < 0) || !(tags & (1 << tag)))
  83                return 0;
  84        else
  85                return 1;
  86}
  87
  88/* Creates entry with tag, or if entry already exists, unions tag to it.
  89 * If storage is not NULL, newly created entry will use it.
  90 * Returns number of entries added, or negative on error.
  91 */
  92static int _add_entry(struct my_tree *tree, u64 s, int32_t tag,
  93                      struct pnfs_inval_tracking *storage)
  94{
  95        int found = 0;
  96        struct pnfs_inval_tracking *pos;
  97
  98        dprintk("%s(%llu, %i, %p) enter\n", __func__, s, tag, storage);
  99        list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
 100                if (pos->it_sector > s)
 101                        continue;
 102                else if (pos->it_sector == s) {
 103                        found = 1;
 104                        break;
 105                } else
 106                        break;
 107        }
 108        if (found) {
 109                pos->it_tags |= (1 << tag);
 110                return 0;
 111        } else {
 112                struct pnfs_inval_tracking *new;
 113                new = storage;
 114                new->it_sector = s;
 115                new->it_tags = (1 << tag);
 116                list_add(&new->it_link, &pos->it_link);
 117                return 1;
 118        }
 119}
 120
 121/* XXXX Really want option to not create */
 122/* Over range, unions tag with existing entries, else creates entry with tag */
 123static int _set_range(struct my_tree *tree, int32_t tag, u64 s, u64 length)
 124{
 125        u64 i;
 126
 127        dprintk("%s(%i, %llu, %llu) enter\n", __func__, tag, s, length);
 128        for (i = normalize(s, tree->mtt_step_size); i < s + length;
 129             i += tree->mtt_step_size)
 130                if (_add_entry(tree, i, tag, NULL))
 131                        return -ENOMEM;
 132        return 0;
 133}
 134
 135/* Ensure that future operations on given range of tree will not malloc */
 136static int _preload_range(struct pnfs_inval_markings *marks,
 137                u64 offset, u64 length)
 138{
 139        u64 start, end, s;
 140        int count, i, used = 0, status = -ENOMEM;
 141        struct pnfs_inval_tracking **storage;
 142        struct my_tree  *tree = &marks->im_tree;
 143
 144        dprintk("%s(%llu, %llu) enter\n", __func__, offset, length);
 145        start = normalize(offset, tree->mtt_step_size);
 146        end = normalize_up(offset + length, tree->mtt_step_size);
 147        count = (int)(end - start) / (int)tree->mtt_step_size;
 148
 149        /* Pre-malloc what memory we might need */
 150        storage = kcalloc(count, sizeof(*storage), GFP_NOFS);
 151        if (!storage)
 152                return -ENOMEM;
 153        for (i = 0; i < count; i++) {
 154                storage[i] = kmalloc(sizeof(struct pnfs_inval_tracking),
 155                                     GFP_NOFS);
 156                if (!storage[i])
 157                        goto out_cleanup;
 158        }
 159
 160        spin_lock_bh(&marks->im_lock);
 161        for (s = start; s < end; s += tree->mtt_step_size)
 162                used += _add_entry(tree, s, INTERNAL_EXISTS, storage[used]);
 163        spin_unlock_bh(&marks->im_lock);
 164
 165        status = 0;
 166
 167 out_cleanup:
 168        for (i = used; i < count; i++) {
 169                if (!storage[i])
 170                        break;
 171                kfree(storage[i]);
 172        }
 173        kfree(storage);
 174        return status;
 175}
 176
 177/* We are relying on page lock to serialize this */
 178int bl_is_sector_init(struct pnfs_inval_markings *marks, sector_t isect)
 179{
 180        int rv;
 181
 182        spin_lock_bh(&marks->im_lock);
 183        rv = _has_tag(&marks->im_tree, isect, EXTENT_INITIALIZED);
 184        spin_unlock_bh(&marks->im_lock);
 185        return rv;
 186}
 187
 188/* Assume start, end already sector aligned */
 189static int
 190_range_has_tag(struct my_tree *tree, u64 start, u64 end, int32_t tag)
 191{
 192        struct pnfs_inval_tracking *pos;
 193        u64 expect = 0;
 194
 195        dprintk("%s(%llu, %llu, %i) enter\n", __func__, start, end, tag);
 196        list_for_each_entry_reverse(pos, &tree->mtt_stub, it_link) {
 197                if (pos->it_sector >= end)
 198                        continue;
 199                if (!expect) {
 200                        if ((pos->it_sector == end - tree->mtt_step_size) &&
 201                            (pos->it_tags & (1 << tag))) {
 202                                expect = pos->it_sector - tree->mtt_step_size;
 203                                if (pos->it_sector < tree->mtt_step_size || expect < start)
 204                                        return 1;
 205                                continue;
 206                        } else {
 207                                return 0;
 208                        }
 209                }
 210                if (pos->it_sector != expect || !(pos->it_tags & (1 << tag)))
 211                        return 0;
 212                expect -= tree->mtt_step_size;
 213                if (expect < start)
 214                        return 1;
 215        }
 216        return 0;
 217}
 218
 219static int is_range_written(struct pnfs_inval_markings *marks,
 220                            sector_t start, sector_t end)
 221{
 222        int rv;
 223
 224        spin_lock_bh(&marks->im_lock);
 225        rv = _range_has_tag(&marks->im_tree, start, end, EXTENT_WRITTEN);
 226        spin_unlock_bh(&marks->im_lock);
 227        return rv;
 228}
 229
 230/* Marks sectors in [offest, offset_length) as having been initialized.
 231 * All lengths are step-aligned, where step is min(pagesize, blocksize).
 232 * Currently assumes offset is page-aligned
 233 */
 234int bl_mark_sectors_init(struct pnfs_inval_markings *marks,
 235                             sector_t offset, sector_t length)
 236{
 237        sector_t start, end;
 238
 239        dprintk("%s(offset=%llu,len=%llu) enter\n",
 240                __func__, (u64)offset, (u64)length);
 241
 242        start = normalize(offset, marks->im_block_size);
 243        end = normalize_up(offset + length, marks->im_block_size);
 244        if (_preload_range(marks, start, end - start))
 245                goto outerr;
 246
 247        spin_lock_bh(&marks->im_lock);
 248        if (_set_range(&marks->im_tree, EXTENT_INITIALIZED, offset, length))
 249                goto out_unlock;
 250        spin_unlock_bh(&marks->im_lock);
 251
 252        return 0;
 253
 254out_unlock:
 255        spin_unlock_bh(&marks->im_lock);
 256outerr:
 257        return -ENOMEM;
 258}
 259
 260/* Marks sectors in [offest, offset+length) as having been written to disk.
 261 * All lengths should be block aligned.
 262 */
 263static int mark_written_sectors(struct pnfs_inval_markings *marks,
 264                                sector_t offset, sector_t length)
 265{
 266        int status;
 267
 268        dprintk("%s(offset=%llu,len=%llu) enter\n", __func__,
 269                (u64)offset, (u64)length);
 270        spin_lock_bh(&marks->im_lock);
 271        status = _set_range(&marks->im_tree, EXTENT_WRITTEN, offset, length);
 272        spin_unlock_bh(&marks->im_lock);
 273        return status;
 274}
 275
 276static void print_short_extent(struct pnfs_block_short_extent *be)
 277{
 278        dprintk("PRINT SHORT EXTENT extent %p\n", be);
 279        if (be) {
 280                dprintk("        be_f_offset %llu\n", (u64)be->bse_f_offset);
 281                dprintk("        be_length   %llu\n", (u64)be->bse_length);
 282        }
 283}
 284
 285static void print_clist(struct list_head *list, unsigned int count)
 286{
 287        struct pnfs_block_short_extent *be;
 288        unsigned int i = 0;
 289
 290        ifdebug(FACILITY) {
 291                printk(KERN_DEBUG "****************\n");
 292                printk(KERN_DEBUG "Extent list looks like:\n");
 293                list_for_each_entry(be, list, bse_node) {
 294                        i++;
 295                        print_short_extent(be);
 296                }
 297                if (i != count)
 298                        printk(KERN_DEBUG "\n\nExpected %u entries\n\n\n", count);
 299                printk(KERN_DEBUG "****************\n");
 300        }
 301}
 302
 303/* Note: In theory, we should do more checking that devid's match between
 304 * old and new, but if they don't, the lists are too corrupt to salvage anyway.
 305 */
 306/* Note this is very similar to bl_add_merge_extent */
 307static void add_to_commitlist(struct pnfs_block_layout *bl,
 308                              struct pnfs_block_short_extent *new)
 309{
 310        struct list_head *clist = &bl->bl_commit;
 311        struct pnfs_block_short_extent *old, *save;
 312        sector_t end = new->bse_f_offset + new->bse_length;
 313
 314        dprintk("%s enter\n", __func__);
 315        print_short_extent(new);
 316        print_clist(clist, bl->bl_count);
 317        bl->bl_count++;
 318        /* Scan for proper place to insert, extending new to the left
 319         * as much as possible.
 320         */
 321        list_for_each_entry_safe(old, save, clist, bse_node) {
 322                if (new->bse_f_offset < old->bse_f_offset)
 323                        break;
 324                if (end <= old->bse_f_offset + old->bse_length) {
 325                        /* Range is already in list */
 326                        bl->bl_count--;
 327                        kfree(new);
 328                        return;
 329                } else if (new->bse_f_offset <=
 330                                old->bse_f_offset + old->bse_length) {
 331                        /* new overlaps or abuts existing be */
 332                        if (new->bse_mdev == old->bse_mdev) {
 333                                /* extend new to fully replace old */
 334                                new->bse_length += new->bse_f_offset -
 335                                                old->bse_f_offset;
 336                                new->bse_f_offset = old->bse_f_offset;
 337                                list_del(&old->bse_node);
 338                                bl->bl_count--;
 339                                kfree(old);
 340                        }
 341                }
 342        }
 343        /* Note that if we never hit the above break, old will not point to a
 344         * valid extent.  However, in that case &old->bse_node==list.
 345         */
 346        list_add_tail(&new->bse_node, &old->bse_node);
 347        /* Scan forward for overlaps.  If we find any, extend new and
 348         * remove the overlapped extent.
 349         */
 350        old = list_prepare_entry(new, clist, bse_node);
 351        list_for_each_entry_safe_continue(old, save, clist, bse_node) {
 352                if (end < old->bse_f_offset)
 353                        break;
 354                /* new overlaps or abuts old */
 355                if (new->bse_mdev == old->bse_mdev) {
 356                        if (end < old->bse_f_offset + old->bse_length) {
 357                                /* extend new to fully cover old */
 358                                end = old->bse_f_offset + old->bse_length;
 359                                new->bse_length = end - new->bse_f_offset;
 360                        }
 361                        list_del(&old->bse_node);
 362                        bl->bl_count--;
 363                        kfree(old);
 364                }
 365        }
 366        dprintk("%s: after merging\n", __func__);
 367        print_clist(clist, bl->bl_count);
 368}
 369
 370/* Note the range described by offset, length is guaranteed to be contained
 371 * within be.
 372 * new will be freed, either by this function or add_to_commitlist if they
 373 * decide not to use it, or after LAYOUTCOMMIT uses it in the commitlist.
 374 */
 375int bl_mark_for_commit(struct pnfs_block_extent *be,
 376                    sector_t offset, sector_t length,
 377                    struct pnfs_block_short_extent *new)
 378{
 379        sector_t new_end, end = offset + length;
 380        struct pnfs_block_layout *bl = container_of(be->be_inval,
 381                                                    struct pnfs_block_layout,
 382                                                    bl_inval);
 383
 384        mark_written_sectors(be->be_inval, offset, length);
 385        /* We want to add the range to commit list, but it must be
 386         * block-normalized, and verified that the normalized range has
 387         * been entirely written to disk.
 388         */
 389        new->bse_f_offset = offset;
 390        offset = normalize(offset, bl->bl_blocksize);
 391        if (offset < new->bse_f_offset) {
 392                if (is_range_written(be->be_inval, offset, new->bse_f_offset))
 393                        new->bse_f_offset = offset;
 394                else
 395                        new->bse_f_offset = offset + bl->bl_blocksize;
 396        }
 397        new_end = normalize_up(end, bl->bl_blocksize);
 398        if (end < new_end) {
 399                if (is_range_written(be->be_inval, end, new_end))
 400                        end = new_end;
 401                else
 402                        end = new_end - bl->bl_blocksize;
 403        }
 404        if (end <= new->bse_f_offset) {
 405                kfree(new);
 406                return 0;
 407        }
 408        new->bse_length = end - new->bse_f_offset;
 409        new->bse_devid = be->be_devid;
 410        new->bse_mdev = be->be_mdev;
 411
 412        spin_lock(&bl->bl_ext_lock);
 413        add_to_commitlist(bl, new);
 414        spin_unlock(&bl->bl_ext_lock);
 415        return 0;
 416}
 417
 418static void print_bl_extent(struct pnfs_block_extent *be)
 419{
 420        dprintk("PRINT EXTENT extent %p\n", be);
 421        if (be) {
 422                dprintk("        be_f_offset %llu\n", (u64)be->be_f_offset);
 423                dprintk("        be_length   %llu\n", (u64)be->be_length);
 424                dprintk("        be_v_offset %llu\n", (u64)be->be_v_offset);
 425                dprintk("        be_state    %d\n", be->be_state);
 426        }
 427}
 428
 429static void
 430destroy_extent(struct kref *kref)
 431{
 432        struct pnfs_block_extent *be;
 433
 434        be = container_of(kref, struct pnfs_block_extent, be_refcnt);
 435        dprintk("%s be=%p\n", __func__, be);
 436        kfree(be);
 437}
 438
 439void
 440bl_put_extent(struct pnfs_block_extent *be)
 441{
 442        if (be) {
 443                dprintk("%s enter %p (%i)\n", __func__, be,
 444                        atomic_read(&be->be_refcnt.refcount));
 445                kref_put(&be->be_refcnt, destroy_extent);
 446        }
 447}
 448
 449struct pnfs_block_extent *bl_alloc_extent(void)
 450{
 451        struct pnfs_block_extent *be;
 452
 453        be = kmalloc(sizeof(struct pnfs_block_extent), GFP_NOFS);
 454        if (!be)
 455                return NULL;
 456        INIT_LIST_HEAD(&be->be_node);
 457        kref_init(&be->be_refcnt);
 458        be->be_inval = NULL;
 459        return be;
 460}
 461
 462static void print_elist(struct list_head *list)
 463{
 464        struct pnfs_block_extent *be;
 465        dprintk("****************\n");
 466        dprintk("Extent list looks like:\n");
 467        list_for_each_entry(be, list, be_node) {
 468                print_bl_extent(be);
 469        }
 470        dprintk("****************\n");
 471}
 472
 473static inline int
 474extents_consistent(struct pnfs_block_extent *old, struct pnfs_block_extent *new)
 475{
 476        /* Note this assumes new->be_f_offset >= old->be_f_offset */
 477        return (new->be_state == old->be_state) &&
 478                ((new->be_state == PNFS_BLOCK_NONE_DATA) ||
 479                 ((new->be_v_offset - old->be_v_offset ==
 480                   new->be_f_offset - old->be_f_offset) &&
 481                  new->be_mdev == old->be_mdev));
 482}
 483
 484/* Adds new to appropriate list in bl, modifying new and removing existing
 485 * extents as appropriate to deal with overlaps.
 486 *
 487 * See bl_find_get_extent for list constraints.
 488 *
 489 * Refcount on new is already set.  If end up not using it, or error out,
 490 * need to put the reference.
 491 *
 492 * bl->bl_ext_lock is held by caller.
 493 */
 494int
 495bl_add_merge_extent(struct pnfs_block_layout *bl,
 496                     struct pnfs_block_extent *new)
 497{
 498        struct pnfs_block_extent *be, *tmp;
 499        sector_t end = new->be_f_offset + new->be_length;
 500        struct list_head *list;
 501
 502        dprintk("%s enter with be=%p\n", __func__, new);
 503        print_bl_extent(new);
 504        list = &bl->bl_extents[bl_choose_list(new->be_state)];
 505        print_elist(list);
 506
 507        /* Scan for proper place to insert, extending new to the left
 508         * as much as possible.
 509         */
 510        list_for_each_entry_safe_reverse(be, tmp, list, be_node) {
 511                if (new->be_f_offset >= be->be_f_offset + be->be_length)
 512                        break;
 513                if (new->be_f_offset >= be->be_f_offset) {
 514                        if (end <= be->be_f_offset + be->be_length) {
 515                                /* new is a subset of existing be*/
 516                                if (extents_consistent(be, new)) {
 517                                        dprintk("%s: new is subset, ignoring\n",
 518                                                __func__);
 519                                        bl_put_extent(new);
 520                                        return 0;
 521                                } else {
 522                                        goto out_err;
 523                                }
 524                        } else {
 525                                /* |<--   be   -->|
 526                                 *          |<--   new   -->| */
 527                                if (extents_consistent(be, new)) {
 528                                        /* extend new to fully replace be */
 529                                        new->be_length += new->be_f_offset -
 530                                                be->be_f_offset;
 531                                        new->be_f_offset = be->be_f_offset;
 532                                        new->be_v_offset = be->be_v_offset;
 533                                        dprintk("%s: removing %p\n", __func__, be);
 534                                        list_del(&be->be_node);
 535                                        bl_put_extent(be);
 536                                } else {
 537                                        goto out_err;
 538                                }
 539                        }
 540                } else if (end >= be->be_f_offset + be->be_length) {
 541                        /* new extent overlap existing be */
 542                        if (extents_consistent(be, new)) {
 543                                /* extend new to fully replace be */
 544                                dprintk("%s: removing %p\n", __func__, be);
 545                                list_del(&be->be_node);
 546                                bl_put_extent(be);
 547                        } else {
 548                                goto out_err;
 549                        }
 550                } else if (end > be->be_f_offset) {
 551                        /*           |<--   be   -->|
 552                         *|<--   new   -->| */
 553                        if (extents_consistent(new, be)) {
 554                                /* extend new to fully replace be */
 555                                new->be_length += be->be_f_offset + be->be_length -
 556                                        new->be_f_offset - new->be_length;
 557                                dprintk("%s: removing %p\n", __func__, be);
 558                                list_del(&be->be_node);
 559                                bl_put_extent(be);
 560                        } else {
 561                                goto out_err;
 562                        }
 563                }
 564        }
 565        /* Note that if we never hit the above break, be will not point to a
 566         * valid extent.  However, in that case &be->be_node==list.
 567         */
 568        list_add(&new->be_node, &be->be_node);
 569        dprintk("%s: inserting new\n", __func__);
 570        print_elist(list);
 571        /* FIXME - The per-list consistency checks have all been done,
 572         * should now check cross-list consistency.
 573         */
 574        return 0;
 575
 576 out_err:
 577        bl_put_extent(new);
 578        return -EIO;
 579}
 580
 581/* Returns extent, or NULL.  If a second READ extent exists, it is returned
 582 * in cow_read, if given.
 583 *
 584 * The extents are kept in two seperate ordered lists, one for READ and NONE,
 585 * one for READWRITE and INVALID.  Within each list, we assume:
 586 * 1. Extents are ordered by file offset.
 587 * 2. For any given isect, there is at most one extents that matches.
 588 */
 589struct pnfs_block_extent *
 590bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect,
 591            struct pnfs_block_extent **cow_read)
 592{
 593        struct pnfs_block_extent *be, *cow, *ret;
 594        int i;
 595
 596        dprintk("%s enter with isect %llu\n", __func__, (u64)isect);
 597        cow = ret = NULL;
 598        spin_lock(&bl->bl_ext_lock);
 599        for (i = 0; i < EXTENT_LISTS; i++) {
 600                list_for_each_entry_reverse(be, &bl->bl_extents[i], be_node) {
 601                        if (isect >= be->be_f_offset + be->be_length)
 602                                break;
 603                        if (isect >= be->be_f_offset) {
 604                                /* We have found an extent */
 605                                dprintk("%s Get %p (%i)\n", __func__, be,
 606                                        atomic_read(&be->be_refcnt.refcount));
 607                                kref_get(&be->be_refcnt);
 608                                if (!ret)
 609                                        ret = be;
 610                                else if (be->be_state != PNFS_BLOCK_READ_DATA)
 611                                        bl_put_extent(be);
 612                                else
 613                                        cow = be;
 614                                break;
 615                        }
 616                }
 617                if (ret &&
 618                    (!cow_read || ret->be_state != PNFS_BLOCK_INVALID_DATA))
 619                        break;
 620        }
 621        spin_unlock(&bl->bl_ext_lock);
 622        if (cow_read)
 623                *cow_read = cow;
 624        print_bl_extent(ret);
 625        return ret;
 626}
 627
 628/* Similar to bl_find_get_extent, but called with lock held, and ignores cow */
 629static struct pnfs_block_extent *
 630bl_find_get_extent_locked(struct pnfs_block_layout *bl, sector_t isect)
 631{
 632        struct pnfs_block_extent *be, *ret = NULL;
 633        int i;
 634
 635        dprintk("%s enter with isect %llu\n", __func__, (u64)isect);
 636        for (i = 0; i < EXTENT_LISTS; i++) {
 637                if (ret)
 638                        break;
 639                list_for_each_entry_reverse(be, &bl->bl_extents[i], be_node) {
 640                        if (isect >= be->be_f_offset + be->be_length)
 641                                break;
 642                        if (isect >= be->be_f_offset) {
 643                                /* We have found an extent */
 644                                dprintk("%s Get %p (%i)\n", __func__, be,
 645                                        atomic_read(&be->be_refcnt.refcount));
 646                                kref_get(&be->be_refcnt);
 647                                ret = be;
 648                                break;
 649                        }
 650                }
 651        }
 652        print_bl_extent(ret);
 653        return ret;
 654}
 655
 656int
 657encode_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
 658                               struct xdr_stream *xdr,
 659                               const struct nfs4_layoutcommit_args *arg)
 660{
 661        struct pnfs_block_short_extent *lce, *save;
 662        unsigned int count = 0;
 663        __be32 *p, *xdr_start;
 664
 665        dprintk("%s enter\n", __func__);
 666        /* BUG - creation of bl_commit is buggy - need to wait for
 667         * entire block to be marked WRITTEN before it can be added.
 668         */
 669        spin_lock(&bl->bl_ext_lock);
 670        /* Want to adjust for possible truncate */
 671        /* We now want to adjust argument range */
 672
 673        /* XDR encode the ranges found */
 674        xdr_start = xdr_reserve_space(xdr, 8);
 675        if (!xdr_start)
 676                goto out;
 677        list_for_each_entry_safe(lce, save, &bl->bl_commit, bse_node) {
 678                p = xdr_reserve_space(xdr, 7 * 4 + sizeof(lce->bse_devid.data));
 679                if (!p)
 680                        break;
 681                p = xdr_encode_opaque_fixed(p, lce->bse_devid.data, NFS4_DEVICEID4_SIZE);
 682                p = xdr_encode_hyper(p, lce->bse_f_offset << SECTOR_SHIFT);
 683                p = xdr_encode_hyper(p, lce->bse_length << SECTOR_SHIFT);
 684                p = xdr_encode_hyper(p, 0LL);
 685                *p++ = cpu_to_be32(PNFS_BLOCK_READWRITE_DATA);
 686                list_move_tail(&lce->bse_node, &bl->bl_committing);
 687                bl->bl_count--;
 688                count++;
 689        }
 690        xdr_start[0] = cpu_to_be32((xdr->p - xdr_start - 1) * 4);
 691        xdr_start[1] = cpu_to_be32(count);
 692out:
 693        spin_unlock(&bl->bl_ext_lock);
 694        dprintk("%s found %i ranges\n", __func__, count);
 695        return 0;
 696}
 697
 698/* Helper function to set_to_rw that initialize a new extent */
 699static void
 700_prep_new_extent(struct pnfs_block_extent *new,
 701                 struct pnfs_block_extent *orig,
 702                 sector_t offset, sector_t length, int state)
 703{
 704        kref_init(&new->be_refcnt);
 705        /* don't need to INIT_LIST_HEAD(&new->be_node) */
 706        memcpy(&new->be_devid, &orig->be_devid, sizeof(struct nfs4_deviceid));
 707        new->be_mdev = orig->be_mdev;
 708        new->be_f_offset = offset;
 709        new->be_length = length;
 710        new->be_v_offset = orig->be_v_offset - orig->be_f_offset + offset;
 711        new->be_state = state;
 712        new->be_inval = orig->be_inval;
 713}
 714
 715/* Tries to merge be with extent in front of it in list.
 716 * Frees storage if not used.
 717 */
 718static struct pnfs_block_extent *
 719_front_merge(struct pnfs_block_extent *be, struct list_head *head,
 720             struct pnfs_block_extent *storage)
 721{
 722        struct pnfs_block_extent *prev;
 723
 724        if (!storage)
 725                goto no_merge;
 726        if (&be->be_node == head || be->be_node.prev == head)
 727                goto no_merge;
 728        prev = list_entry(be->be_node.prev, struct pnfs_block_extent, be_node);
 729        if ((prev->be_f_offset + prev->be_length != be->be_f_offset) ||
 730            !extents_consistent(prev, be))
 731                goto no_merge;
 732        _prep_new_extent(storage, prev, prev->be_f_offset,
 733                         prev->be_length + be->be_length, prev->be_state);
 734        list_replace(&prev->be_node, &storage->be_node);
 735        bl_put_extent(prev);
 736        list_del(&be->be_node);
 737        bl_put_extent(be);
 738        return storage;
 739
 740 no_merge:
 741        kfree(storage);
 742        return be;
 743}
 744
 745static u64
 746set_to_rw(struct pnfs_block_layout *bl, u64 offset, u64 length)
 747{
 748        u64 rv = offset + length;
 749        struct pnfs_block_extent *be, *e1, *e2, *e3, *new, *old;
 750        struct pnfs_block_extent *children[3];
 751        struct pnfs_block_extent *merge1 = NULL, *merge2 = NULL;
 752        int i = 0, j;
 753
 754        dprintk("%s(%llu, %llu)\n", __func__, offset, length);
 755        /* Create storage for up to three new extents e1, e2, e3 */
 756        e1 = kmalloc(sizeof(*e1), GFP_ATOMIC);
 757        e2 = kmalloc(sizeof(*e2), GFP_ATOMIC);
 758        e3 = kmalloc(sizeof(*e3), GFP_ATOMIC);
 759        /* BUG - we are ignoring any failure */
 760        if (!e1 || !e2 || !e3)
 761                goto out_nosplit;
 762
 763        spin_lock(&bl->bl_ext_lock);
 764        be = bl_find_get_extent_locked(bl, offset);
 765        rv = be->be_f_offset + be->be_length;
 766        if (be->be_state != PNFS_BLOCK_INVALID_DATA) {
 767                spin_unlock(&bl->bl_ext_lock);
 768                goto out_nosplit;
 769        }
 770        /* Add e* to children, bumping e*'s krefs */
 771        if (be->be_f_offset != offset) {
 772                _prep_new_extent(e1, be, be->be_f_offset,
 773                                 offset - be->be_f_offset,
 774                                 PNFS_BLOCK_INVALID_DATA);
 775                children[i++] = e1;
 776                print_bl_extent(e1);
 777        } else
 778                merge1 = e1;
 779        _prep_new_extent(e2, be, offset,
 780                         min(length, be->be_f_offset + be->be_length - offset),
 781                         PNFS_BLOCK_READWRITE_DATA);
 782        children[i++] = e2;
 783        print_bl_extent(e2);
 784        if (offset + length < be->be_f_offset + be->be_length) {
 785                _prep_new_extent(e3, be, e2->be_f_offset + e2->be_length,
 786                                 be->be_f_offset + be->be_length -
 787                                 offset - length,
 788                                 PNFS_BLOCK_INVALID_DATA);
 789                children[i++] = e3;
 790                print_bl_extent(e3);
 791        } else
 792                merge2 = e3;
 793
 794        /* Remove be from list, and insert the e* */
 795        /* We don't get refs on e*, since this list is the base reference
 796         * set when init'ed.
 797         */
 798        if (i < 3)
 799                children[i] = NULL;
 800        new = children[0];
 801        list_replace(&be->be_node, &new->be_node);
 802        bl_put_extent(be);
 803        new = _front_merge(new, &bl->bl_extents[RW_EXTENT], merge1);
 804        for (j = 1; j < i; j++) {
 805                old = new;
 806                new = children[j];
 807                list_add(&new->be_node, &old->be_node);
 808        }
 809        if (merge2) {
 810                /* This is a HACK, should just create a _back_merge function */
 811                new = list_entry(new->be_node.next,
 812                                 struct pnfs_block_extent, be_node);
 813                new = _front_merge(new, &bl->bl_extents[RW_EXTENT], merge2);
 814        }
 815        spin_unlock(&bl->bl_ext_lock);
 816
 817        /* Since we removed the base reference above, be is now scheduled for
 818         * destruction.
 819         */
 820        bl_put_extent(be);
 821        dprintk("%s returns %llu after split\n", __func__, rv);
 822        return rv;
 823
 824 out_nosplit:
 825        kfree(e1);
 826        kfree(e2);
 827        kfree(e3);
 828        dprintk("%s returns %llu without splitting\n", __func__, rv);
 829        return rv;
 830}
 831
 832void
 833clean_pnfs_block_layoutupdate(struct pnfs_block_layout *bl,
 834                              const struct nfs4_layoutcommit_args *arg,
 835                              int status)
 836{
 837        struct pnfs_block_short_extent *lce, *save;
 838
 839        dprintk("%s status %d\n", __func__, status);
 840        list_for_each_entry_safe(lce, save, &bl->bl_committing, bse_node) {
 841                if (likely(!status)) {
 842                        u64 offset = lce->bse_f_offset;
 843                        u64 end = offset + lce->bse_length;
 844
 845                        do {
 846                                offset = set_to_rw(bl, offset, end - offset);
 847                        } while (offset < end);
 848                        list_del(&lce->bse_node);
 849
 850                        kfree(lce);
 851                } else {
 852                        list_del(&lce->bse_node);
 853                        spin_lock(&bl->bl_ext_lock);
 854                        add_to_commitlist(bl, lce);
 855                        spin_unlock(&bl->bl_ext_lock);
 856                }
 857        }
 858}
 859
 860int bl_push_one_short_extent(struct pnfs_inval_markings *marks)
 861{
 862        struct pnfs_block_short_extent *new;
 863
 864        new = kmalloc(sizeof(*new), GFP_NOFS);
 865        if (unlikely(!new))
 866                return -ENOMEM;
 867
 868        spin_lock_bh(&marks->im_lock);
 869        list_add(&new->bse_node, &marks->im_extents);
 870        spin_unlock_bh(&marks->im_lock);
 871
 872        return 0;
 873}
 874
 875struct pnfs_block_short_extent *
 876bl_pop_one_short_extent(struct pnfs_inval_markings *marks)
 877{
 878        struct pnfs_block_short_extent *rv = NULL;
 879
 880        spin_lock_bh(&marks->im_lock);
 881        if (!list_empty(&marks->im_extents)) {
 882                rv = list_entry((&marks->im_extents)->next,
 883                                struct pnfs_block_short_extent, bse_node);
 884                list_del_init(&rv->bse_node);
 885        }
 886        spin_unlock_bh(&marks->im_lock);
 887
 888        return rv;
 889}
 890
 891void bl_free_short_extents(struct pnfs_inval_markings *marks, int num_to_free)
 892{
 893        struct pnfs_block_short_extent *se = NULL, *tmp;
 894
 895        if (num_to_free <= 0)
 896                return;
 897
 898        spin_lock(&marks->im_lock);
 899        list_for_each_entry_safe(se, tmp, &marks->im_extents, bse_node) {
 900                list_del(&se->bse_node);
 901                kfree(se);
 902                if (--num_to_free == 0)
 903                        break;
 904        }
 905        spin_unlock(&marks->im_lock);
 906
 907        BUG_ON(num_to_free > 0);
 908}
 909