fs/nfs/blocklayout/extent_tree.c

   1 /*
   2  * Copyright (c) 2014 Christoph Hellwig.
   3  */
   4
   5 #include "blocklayout.h"
   6
   7 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
   8
   9 static inline struct pnfs_block_extent *
  10 ext_node(struct rb_node *node)
  11 {
  12         return rb_entry(node, struct pnfs_block_extent, be_node);
  13 }
  14
  15 static struct pnfs_block_extent *
  16 ext_tree_first(struct rb_root *root)
  17 {
  18         struct rb_node *node = rb_first(root);
  19         return node ? ext_node(node) : NULL;
  20 }
  21
  22 static struct pnfs_block_extent *
  23 ext_tree_prev(struct pnfs_block_extent *be)
  24 {
  25         struct rb_node *node = rb_prev(&be->be_node);
  26         return node ? ext_node(node) : NULL;
  27 }
  28
  29 static struct pnfs_block_extent *
  30 ext_tree_next(struct pnfs_block_extent *be)
  31 {
  32         struct rb_node *node = rb_next(&be->be_node);
  33         return node ? ext_node(node) : NULL;
  34 }
  35
  36 static inline sector_t
  37 ext_f_end(struct pnfs_block_extent *be)
  38 {
  39         return be->be_f_offset + be->be_length;
  40 }
  41
  42 static struct pnfs_block_extent *
  43 __ext_tree_search(struct rb_root *root, sector_t start)
  44 {
  45         struct rb_node *node = root->rb_node;
  46         struct pnfs_block_extent *be = NULL;
  47
  48         while (node) {
  49                 be = ext_node(node);
  50                 if (start < be->be_f_offset)
  51                         node = node->rb_left;
  52                 else if (start >= ext_f_end(be))
  53                         node = node->rb_right;
  54                 else
  55                         return be;
  56         }
  57
  58         if (be) {
  59                 if (start < be->be_f_offset)
  60                         return be;
  61
  62                 if (start >= ext_f_end(be))
  63                         return ext_tree_next(be);
  64         }
  65
  66         return NULL;
  67 }
  68
  69 static bool
  70 ext_can_merge(struct pnfs_block_extent *be1, struct pnfs_block_extent *be2)
  71 {
  72         if (be1->be_state != be2->be_state)
  73                 return false;
  74         if (be1->be_device != be2->be_device)
  75                 return false;
  76
  77         if (be1->be_f_offset + be1->be_length != be2->be_f_offset)
  78                 return false;
  79
  80         if (be1->be_state != PNFS_BLOCK_NONE_DATA &&
  81             (be1->be_v_offset + be1->be_length != be2->be_v_offset))
  82                 return false;
  83
  84         if (be1->be_state == PNFS_BLOCK_INVALID_DATA &&
  85             be1->be_tag != be2->be_tag)
  86                 return false;
  87
  88         return true;
  89 }
  90
  91 static struct pnfs_block_extent *
  92 ext_try_to_merge_left(struct rb_root *root, struct pnfs_block_extent *be)
  93 {
  94         struct pnfs_block_extent *left = ext_tree_prev(be);
  95
  96         if (left && ext_can_merge(left, be)) {
  97                 left->be_length += be->be_length;
  98                 rb_erase(&be->be_node, root);
  99                 nfs4_put_deviceid_node(be->be_device);
 100                 kfree(be);
 101                 return left;
 102         }
 103
 104         return be;
 105 }
 106
 107 static struct pnfs_block_extent *
 108 ext_try_to_merge_right(struct rb_root *root, struct pnfs_block_extent *be)
 109 {
 110         struct pnfs_block_extent *right = ext_tree_next(be);
 111
 112         if (right && ext_can_merge(be, right)) {
 113                 be->be_length += right->be_length;
 114                 rb_erase(&right->be_node, root);
 115                 nfs4_put_deviceid_node(right->be_device);
 116                 kfree(right);
 117         }
 118
 119         return be;
 120 }
 121
 122 static void
 123 __ext_tree_insert(struct rb_root *root,
 124                 struct pnfs_block_extent *new, bool merge_ok)
 125 {
 126         struct rb_node **p = &root->rb_node, *parent = NULL;
 127         struct pnfs_block_extent *be;
 128
 129         while (*p) {
 130                 parent = *p;
 131                 be = ext_node(parent);
 132
 133                 if (new->be_f_offset < be->be_f_offset) {
 134                         if (merge_ok && ext_can_merge(new, be)) {
 135                                 be->be_f_offset = new->be_f_offset;
 136                                 if (be->be_state != PNFS_BLOCK_NONE_DATA)
 137                                         be->be_v_offset = new->be_v_offset;
 138                                 be->be_length += new->be_length;
 139                                 be = ext_try_to_merge_left(root, be);
 140                                 goto free_new;
 141                         }
 142                         p = &(*p)->rb_left;
 143                 } else if (new->be_f_offset >= ext_f_end(be)) {
 144                         if (merge_ok && ext_can_merge(be, new)) {
 145                                 be->be_length += new->be_length;
 146                                 be = ext_try_to_merge_right(root, be);
 147                                 goto free_new;
 148                         }
 149                         p = &(*p)->rb_right;
 150                 } else {
 151                         BUG();
 152                 }
 153         }
 154
 155         rb_link_node(&new->be_node, parent, p);
 156         rb_insert_color(&new->be_node, root);
 157         return;
 158 free_new:
 159         nfs4_put_deviceid_node(new->be_device);
 160         kfree(new);
 161 }
 162
 163 static int
 164 __ext_tree_remove(struct rb_root *root, sector_t start, sector_t end)
 165 {
 166         struct pnfs_block_extent *be;
 167         sector_t len1 = 0, len2 = 0;
 168         sector_t orig_f_offset;
 169         sector_t orig_v_offset;
 170         sector_t orig_len;
 171
 172         be = __ext_tree_search(root, start);
 173         if (!be)
 174                 return 0;
 175         if (be->be_f_offset >= end)
 176                 return 0;
 177
 178         orig_f_offset = be->be_f_offset;
 179         orig_v_offset = be->be_v_offset;
 180         orig_len = be->be_length;
 181
 182         if (start > be->be_f_offset)
 183                 len1 = start - be->be_f_offset;
 184         if (ext_f_end(be) > end)
 185                 len2 = ext_f_end(be) - end;
 186
 187         if (len2 > 0) {
 188                 if (len1 > 0) {
 189                         struct pnfs_block_extent *new;
 190
 191                         new = kzalloc(sizeof(*new), GFP_ATOMIC);
 192                         if (!new)
 193                                 return -ENOMEM;
 194
 195                         be->be_length = len1;
 196
 197                         new->be_f_offset = end;
 198                         if (be->be_state != PNFS_BLOCK_NONE_DATA) {
 199                                 new->be_v_offset =
 200                                         orig_v_offset + orig_len - len2;
 201                         }
 202                         new->be_length = len2;
 203                         new->be_state = be->be_state;
 204                         new->be_tag = be->be_tag;
 205                         new->be_device = nfs4_get_deviceid(be->be_device);
 206
 207                         __ext_tree_insert(root, new, true);
 208                 } else {
 209                         be->be_f_offset = end;
 210                         if (be->be_state != PNFS_BLOCK_NONE_DATA) {
 211                                 be->be_v_offset =
 212                                         orig_v_offset + orig_len - len2;
 213                         }
 214                         be->be_length = len2;
 215                 }
 216         } else {
 217                 if (len1 > 0) {
 218                         be->be_length = len1;
 219                         be = ext_tree_next(be);
 220                 }
 221
 222                 while (be && ext_f_end(be) <= end) {
 223                         struct pnfs_block_extent *next = ext_tree_next(be);
 224
 225                         rb_erase(&be->be_node, root);
 226                         nfs4_put_deviceid_node(be->be_device);
 227                         kfree(be);
 228                         be = next;
 229                 }
 230
 231                 if (be && be->be_f_offset < end) {
 232                         len1 = ext_f_end(be) - end;
 233                         be->be_f_offset = end;
 234                         if (be->be_state != PNFS_BLOCK_NONE_DATA)
 235                                 be->be_v_offset += be->be_length - len1;
 236                         be->be_length = len1;
 237                 }
 238         }
 239
 240         return 0;
 241 }
 242
 243 int
 244 ext_tree_insert(struct pnfs_block_layout *bl, struct pnfs_block_extent *new)
 245 {
 246         struct pnfs_block_extent *be;
 247         struct rb_root *root;
 248         int err = 0;
 249
 250         switch (new->be_state) {
 251         case PNFS_BLOCK_READWRITE_DATA:
 252         case PNFS_BLOCK_INVALID_DATA:
 253                 root = &bl->bl_ext_rw;
 254                 break;
 255         case PNFS_BLOCK_READ_DATA:
 256         case PNFS_BLOCK_NONE_DATA:
 257                 root = &bl->bl_ext_ro;
 258                 break;
 259         default:
 260                 dprintk("invalid extent type\n");
 261                 return -EINVAL;
 262         }
 263
 264         spin_lock(&bl->bl_ext_lock);
 265 retry:
 266         be = __ext_tree_search(root, new->be_f_offset);
 267         if (!be || be->be_f_offset >= ext_f_end(new)) {
 268                 __ext_tree_insert(root, new, true);
 269         } else if (new->be_f_offset >= be->be_f_offset) {
 270                 if (ext_f_end(new) <= ext_f_end(be)) {
 271                         nfs4_put_deviceid_node(new->be_device);
 272                         kfree(new);
 273                 } else {
 274                         sector_t new_len = ext_f_end(new) - ext_f_end(be);
 275                         sector_t diff = new->be_length - new_len;
 276
 277                         new->be_f_offset += diff;
 278                         new->be_v_offset += diff;
 279                         new->be_length = new_len;
 280                         goto retry;
 281                 }
 282         } else if (ext_f_end(new) <= ext_f_end(be)) {
 283                 new->be_length = be->be_f_offset - new->be_f_offset;
 284                 __ext_tree_insert(root, new, true);
 285         } else {
 286                 struct pnfs_block_extent *split;
 287                 sector_t new_len = ext_f_end(new) - ext_f_end(be);
 288                 sector_t diff = new->be_length - new_len;
 289
 290                 split = kmemdup(new, sizeof(*new), GFP_ATOMIC);
 291                 if (!split) {
 292                         err = -EINVAL;
 293                         goto out;
 294                 }
 295
 296                 split->be_length = be->be_f_offset - split->be_f_offset;
 297                 split->be_device = nfs4_get_deviceid(new->be_device);
 298                 __ext_tree_insert(root, split, true);
 299
 300                 new->be_f_offset += diff;
 301                 new->be_v_offset += diff;
 302                 new->be_length = new_len;
 303                 goto retry;
 304         }
 305 out:
 306         spin_unlock(&bl->bl_ext_lock);
 307         return err;
 308 }
 309
 310 static bool
 311 __ext_tree_lookup(struct rb_root *root, sector_t isect,
 312                 struct pnfs_block_extent *ret)
 313 {
 314         struct rb_node *node;
 315         struct pnfs_block_extent *be;
 316
 317         node = root->rb_node;
 318         while (node) {
 319                 be = ext_node(node);
 320                 if (isect < be->be_f_offset)
 321                         node = node->rb_left;
 322                 else if (isect >= ext_f_end(be))
 323                         node = node->rb_right;
 324                 else {
 325                         *ret = *be;
 326                         return true;
 327                 }
 328         }
 329
 330         return false;
 331 }
 332
 333 bool
 334 ext_tree_lookup(struct pnfs_block_layout *bl, sector_t isect,
 335             struct pnfs_block_extent *ret, bool rw)
 336 {
 337         bool found = false;
 338
 339         spin_lock(&bl->bl_ext_lock);
 340         if (!rw)
 341                 found = __ext_tree_lookup(&bl->bl_ext_ro, isect, ret);
 342         if (!found)
 343                 found = __ext_tree_lookup(&bl->bl_ext_rw, isect, ret);
 344         spin_unlock(&bl->bl_ext_lock);
 345
 346         return found;
 347 }
 348
 349 int ext_tree_remove(struct pnfs_block_layout *bl, bool rw,
 350                 sector_t start, sector_t end)
 351 {
 352         int err, err2;
 353
 354         spin_lock(&bl->bl_ext_lock);
 355         err = __ext_tree_remove(&bl->bl_ext_ro, start, end);
 356         if (rw) {
 357                 err2 = __ext_tree_remove(&bl->bl_ext_rw, start, end);
 358                 if (!err)
 359                         err = err2;
 360         }
 361         spin_unlock(&bl->bl_ext_lock);
 362
 363         return err;
 364 }
 365
 366 static int
 367 ext_tree_split(struct rb_root *root, struct pnfs_block_extent *be,
 368                 sector_t split)
 369 {
 370         struct pnfs_block_extent *new;
 371         sector_t orig_len = be->be_length;
 372
 373         new = kzalloc(sizeof(*new), GFP_ATOMIC);
 374         if (!new)
 375                 return -ENOMEM;
 376
 377         be->be_length = split - be->be_f_offset;
 378
 379         new->be_f_offset = split;
 380         if (be->be_state != PNFS_BLOCK_NONE_DATA)
 381                 new->be_v_offset = be->be_v_offset + be->be_length;
 382         new->be_length = orig_len - be->be_length;
 383         new->be_state = be->be_state;
 384         new->be_tag = be->be_tag;
 385         new->be_device = nfs4_get_deviceid(be->be_device);
 386
 387         __ext_tree_insert(root, new, false);
 388         return 0;
 389 }
 390
 391 int
 392 ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,
 393                 sector_t len)
 394 {
 395         struct rb_root *root = &bl->bl_ext_rw;
 396         sector_t end = start + len;
 397         struct pnfs_block_extent *be;
 398         int err = 0;
 399
 400         spin_lock(&bl->bl_ext_lock);
 401         /*
 402          * First remove all COW extents or holes from written to range.
 403          */
 404         err = __ext_tree_remove(&bl->bl_ext_ro, start, end);
 405         if (err)
 406                 goto out;
 407
 408         /*
 409          * Then mark all invalid extents in the range as written to.
 410          */
 411         for (be = __ext_tree_search(root, start); be; be = ext_tree_next(be)) {
 412                 if (be->be_f_offset >= end)
 413                         break;
 414
 415                 if (be->be_state != PNFS_BLOCK_INVALID_DATA || be->be_tag)
 416                         continue;
 417
 418                 if (be->be_f_offset < start) {
 419                         struct pnfs_block_extent *left = ext_tree_prev(be);
 420
 421                         if (left && ext_can_merge(left, be)) {
 422                                 sector_t diff = start - be->be_f_offset;
 423
 424                                 left->be_length += diff;
 425
 426                                 be->be_f_offset += diff;
 427                                 be->be_v_offset += diff;
 428                                 be->be_length -= diff;
 429                         } else {
 430                                 err = ext_tree_split(root, be, start);
 431                                 if (err)
 432                                         goto out;
 433                         }
 434                 }
 435
 436                 if (ext_f_end(be) > end) {
 437                         struct pnfs_block_extent *right = ext_tree_next(be);
 438
 439                         if (right && ext_can_merge(be, right)) {
 440                                 sector_t diff = end - be->be_f_offset;
 441
 442                                 be->be_length -= diff;
 443
 444                                 right->be_f_offset -= diff;
 445                                 right->be_v_offset -= diff;
 446                                 right->be_length += diff;
 447                         } else {
 448                                 err = ext_tree_split(root, be, end);
 449                                 if (err)
 450                                         goto out;
 451                         }
 452                 }
 453
 454                 if (be->be_f_offset >= start && ext_f_end(be) <= end) {
 455                         be->be_tag = EXTENT_WRITTEN;
 456                         be = ext_try_to_merge_left(root, be);
 457                         be = ext_try_to_merge_right(root, be);
 458                 }
 459         }
 460 out:
 461         spin_unlock(&bl->bl_ext_lock);
 462         return err;
 463 }
 464
 465 int
 466 ext_tree_encode_commit(struct pnfs_block_layout *bl, struct xdr_stream *xdr)
 467 {
 468         struct pnfs_block_extent *be;
 469         unsigned int count = 0;
 470         __be32 *p, *xdr_start;
 471         int ret = 0;
 472
 473         dprintk("%s enter\n", __func__);
 474
 475         xdr_start = xdr_reserve_space(xdr, 8);
 476         if (!xdr_start)
 477                 return -ENOSPC;
 478
 479         spin_lock(&bl->bl_ext_lock);
 480         for (be = ext_tree_first(&bl->bl_ext_rw); be; be = ext_tree_next(be)) {
 481                 if (be->be_state != PNFS_BLOCK_INVALID_DATA ||
 482                     be->be_tag != EXTENT_WRITTEN)
 483                         continue;
 484
 485                 p = xdr_reserve_space(xdr, 7 * sizeof(__be32) +
 486                                         NFS4_DEVICEID4_SIZE);
 487                 if (!p) {
 488                         printk("%s: out of space for extent list\n", __func__);
 489                         ret = -ENOSPC;
 490                         break;
 491                 }
 492
 493                 p = xdr_encode_opaque_fixed(p, be->be_device->deviceid.data,
 494                                 NFS4_DEVICEID4_SIZE);
 495                 p = xdr_encode_hyper(p, be->be_f_offset << SECTOR_SHIFT);
 496                 p = xdr_encode_hyper(p, be->be_length << SECTOR_SHIFT);
 497                 p = xdr_encode_hyper(p, 0LL);
 498                 *p++ = cpu_to_be32(PNFS_BLOCK_READWRITE_DATA);
 499
 500                 be->be_tag = EXTENT_COMMITTING;
 501                 count++;
 502         }
 503         spin_unlock(&bl->bl_ext_lock);
 504
 505         xdr_start[0] = cpu_to_be32((xdr->p - xdr_start - 1) * 4);
 506         xdr_start[1] = cpu_to_be32(count);
 507
 508         dprintk("%s found %i ranges\n", __func__, count);
 509         return ret;
 510 }
 511
 512 void
 513 ext_tree_mark_committed(struct pnfs_block_layout *bl, int status)
 514 {
 515         struct rb_root *root = &bl->bl_ext_rw;
 516         struct pnfs_block_extent *be;
 517
 518         dprintk("%s status %d\n", __func__, status);
 519
 520         spin_lock(&bl->bl_ext_lock);
 521         for (be = ext_tree_first(root); be; be = ext_tree_next(be)) {
 522                 if (be->be_state != PNFS_BLOCK_INVALID_DATA ||
 523                     be->be_tag != EXTENT_COMMITTING)
 524                         continue;
 525
 526                 if (status) {
 527                         /*
 528                          * Mark as written and try again.
 529                          *
 530                          * XXX: some real error handling here wouldn't hurt..
 531                          */
 532                         be->be_tag = EXTENT_WRITTEN;
 533                 } else {
 534                         be->be_state = PNFS_BLOCK_READWRITE_DATA;
 535                         be->be_tag = 0;
 536                 }
 537
 538                 be = ext_try_to_merge_left(root, be);
 539                 be = ext_try_to_merge_right(root, be);
 540         }
 541         spin_unlock(&bl->bl_ext_lock);
 542 }