fs/btrfs/file.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/fs.h>
   7 #include <linux/pagemap.h>
   8 #include <linux/time.h>
   9 #include <linux/init.h>
  10 #include <linux/string.h>
  11 #include <linux/backing-dev.h>
  12 #include <linux/falloc.h>
  13 #include <linux/writeback.h>
  14 #include <linux/compat.h>
  15 #include <linux/slab.h>
  16 #include <linux/btrfs.h>
  17 #include <linux/uio.h>
  18 #include <linux/iversion.h>
  19 #include "ctree.h"
  20 #include "disk-io.h"
  21 #include "transaction.h"
  22 #include "btrfs_inode.h"
  23 #include "print-tree.h"
  24 #include "tree-log.h"
  25 #include "locking.h"
  26 #include "volumes.h"
  27 #include "qgroup.h"
  28 #include "compression.h"
  29 #include "delalloc-space.h"
  30 #include "reflink.h"
  31
  32 static struct kmem_cache *btrfs_inode_defrag_cachep;
  33 /*
  34  * when auto defrag is enabled we
  35  * queue up these defrag structs to remember which
  36  * inodes need defragging passes
  37  */
  38 struct inode_defrag {
  39         struct rb_node rb_node;
  40         /* objectid */
  41         u64 ino;
  42         /*
  43          * transid where the defrag was added, we search for
  44          * extents newer than this
  45          */
  46         u64 transid;
  47
  48         /* root objectid */
  49         u64 root;
  50
  51         /* last offset we were able to defrag */
  52         u64 last_offset;
  53
  54         /* if we've wrapped around back to zero once already */
  55         int cycled;
  56 };
  57
  58 static int __compare_inode_defrag(struct inode_defrag *defrag1,
  59                                   struct inode_defrag *defrag2)
  60 {
  61         if (defrag1->root > defrag2->root)
  62                 return 1;
  63         else if (defrag1->root < defrag2->root)
  64                 return -1;
  65         else if (defrag1->ino > defrag2->ino)
  66                 return 1;
  67         else if (defrag1->ino < defrag2->ino)
  68                 return -1;
  69         else
  70                 return 0;
  71 }
  72
  73 /* pop a record for an inode into the defrag tree.  The lock
  74  * must be held already
  75  *
  76  * If you're inserting a record for an older transid than an
  77  * existing record, the transid already in the tree is lowered
  78  *
  79  * If an existing record is found the defrag item you
  80  * pass in is freed
  81  */
  82 static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
  83                                     struct inode_defrag *defrag)
  84 {
  85         struct btrfs_fs_info *fs_info = inode->root->fs_info;
  86         struct inode_defrag *entry;
  87         struct rb_node **p;
  88         struct rb_node *parent = NULL;
  89         int ret;
  90
  91         p = &fs_info->defrag_inodes.rb_node;
  92         while (*p) {
  93                 parent = *p;
  94                 entry = rb_entry(parent, struct inode_defrag, rb_node);
  95
  96                 ret = __compare_inode_defrag(defrag, entry);
  97                 if (ret < 0)
  98                         p = &parent->rb_left;
  99                 else if (ret > 0)
 100                         p = &parent->rb_right;
 101                 else {
 102                         /* if we're reinserting an entry for
 103                          * an old defrag run, make sure to
 104                          * lower the transid of our existing record
 105                          */
 106                         if (defrag->transid < entry->transid)
 107                                 entry->transid = defrag->transid;
 108                         if (defrag->last_offset > entry->last_offset)
 109                                 entry->last_offset = defrag->last_offset;
 110                         return -EEXIST;
 111                 }
 112         }
 113         set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
 114         rb_link_node(&defrag->rb_node, parent, p);
 115         rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
 116         return 0;
 117 }
 118
 119 static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
 120 {
 121         if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
 122                 return 0;
 123
 124         if (btrfs_fs_closing(fs_info))
 125                 return 0;
 126
 127         return 1;
 128 }
 129
 130 /*
 131  * insert a defrag record for this inode if auto defrag is
 132  * enabled
 133  */
 134 int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
 135                            struct btrfs_inode *inode)
 136 {
 137         struct btrfs_root *root = inode->root;
 138         struct btrfs_fs_info *fs_info = root->fs_info;
 139         struct inode_defrag *defrag;
 140         u64 transid;
 141         int ret;
 142
 143         if (!__need_auto_defrag(fs_info))
 144                 return 0;
 145
 146         if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
 147                 return 0;
 148
 149         if (trans)
 150                 transid = trans->transid;
 151         else
 152                 transid = inode->root->last_trans;
 153
 154         defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
 155         if (!defrag)
 156                 return -ENOMEM;
 157
 158         defrag->ino = btrfs_ino(inode);
 159         defrag->transid = transid;
 160         defrag->root = root->root_key.objectid;
 161
 162         spin_lock(&fs_info->defrag_inodes_lock);
 163         if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
 164                 /*
 165                  * If we set IN_DEFRAG flag and evict the inode from memory,
 166                  * and then re-read this inode, this new inode doesn't have
 167                  * IN_DEFRAG flag. At the case, we may find the existed defrag.
 168                  */
 169                 ret = __btrfs_add_inode_defrag(inode, defrag);
 170                 if (ret)
 171                         kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 172         } else {
 173                 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 174         }
 175         spin_unlock(&fs_info->defrag_inodes_lock);
 176         return 0;
 177 }
 178
 179 /*
 180  * Requeue the defrag object. If there is a defrag object that points to
 181  * the same inode in the tree, we will merge them together (by
 182  * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
 183  */
 184 static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
 185                                        struct inode_defrag *defrag)
 186 {
 187         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 188         int ret;
 189
 190         if (!__need_auto_defrag(fs_info))
 191                 goto out;
 192
 193         /*
 194          * Here we don't check the IN_DEFRAG flag, because we need merge
 195          * them together.
 196          */
 197         spin_lock(&fs_info->defrag_inodes_lock);
 198         ret = __btrfs_add_inode_defrag(inode, defrag);
 199         spin_unlock(&fs_info->defrag_inodes_lock);
 200         if (ret)
 201                 goto out;
 202         return;
 203 out:
 204         kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 205 }
 206
 207 /*
 208  * pick the defragable inode that we want, if it doesn't exist, we will get
 209  * the next one.
 210  */
 211 static struct inode_defrag *
 212 btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
 213 {
 214         struct inode_defrag *entry = NULL;
 215         struct inode_defrag tmp;
 216         struct rb_node *p;
 217         struct rb_node *parent = NULL;
 218         int ret;
 219
 220         tmp.ino = ino;
 221         tmp.root = root;
 222
 223         spin_lock(&fs_info->defrag_inodes_lock);
 224         p = fs_info->defrag_inodes.rb_node;
 225         while (p) {
 226                 parent = p;
 227                 entry = rb_entry(parent, struct inode_defrag, rb_node);
 228
 229                 ret = __compare_inode_defrag(&tmp, entry);
 230                 if (ret < 0)
 231                         p = parent->rb_left;
 232                 else if (ret > 0)
 233                         p = parent->rb_right;
 234                 else
 235                         goto out;
 236         }
 237
 238         if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
 239                 parent = rb_next(parent);
 240                 if (parent)
 241                         entry = rb_entry(parent, struct inode_defrag, rb_node);
 242                 else
 243                         entry = NULL;
 244         }
 245 out:
 246         if (entry)
 247                 rb_erase(parent, &fs_info->defrag_inodes);
 248         spin_unlock(&fs_info->defrag_inodes_lock);
 249         return entry;
 250 }
 251
 252 void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
 253 {
 254         struct inode_defrag *defrag;
 255         struct rb_node *node;
 256
 257         spin_lock(&fs_info->defrag_inodes_lock);
 258         node = rb_first(&fs_info->defrag_inodes);
 259         while (node) {
 260                 rb_erase(node, &fs_info->defrag_inodes);
 261                 defrag = rb_entry(node, struct inode_defrag, rb_node);
 262                 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 263
 264                 cond_resched_lock(&fs_info->defrag_inodes_lock);
 265
 266                 node = rb_first(&fs_info->defrag_inodes);
 267         }
 268         spin_unlock(&fs_info->defrag_inodes_lock);
 269 }
 270
 271 #define BTRFS_DEFRAG_BATCH      1024
 272
 273 static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
 274                                     struct inode_defrag *defrag)
 275 {
 276         struct btrfs_root *inode_root;
 277         struct inode *inode;
 278         struct btrfs_ioctl_defrag_range_args range;
 279         int num_defrag;
 280         int ret;
 281
 282         /* get the inode */
 283         inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
 284         if (IS_ERR(inode_root)) {
 285                 ret = PTR_ERR(inode_root);
 286                 goto cleanup;
 287         }
 288
 289         inode = btrfs_iget(fs_info->sb, defrag->ino, inode_root);
 290         btrfs_put_root(inode_root);
 291         if (IS_ERR(inode)) {
 292                 ret = PTR_ERR(inode);
 293                 goto cleanup;
 294         }
 295
 296         /* do a chunk of defrag */
 297         clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
 298         memset(&range, 0, sizeof(range));
 299         range.len = (u64)-1;
 300         range.start = defrag->last_offset;
 301
 302         sb_start_write(fs_info->sb);
 303         num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
 304                                        BTRFS_DEFRAG_BATCH);
 305         sb_end_write(fs_info->sb);
 306         /*
 307          * if we filled the whole defrag batch, there
 308          * must be more work to do.  Queue this defrag
 309          * again
 310          */
 311         if (num_defrag == BTRFS_DEFRAG_BATCH) {
 312                 defrag->last_offset = range.start;
 313                 btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
 314         } else if (defrag->last_offset && !defrag->cycled) {
 315                 /*
 316                  * we didn't fill our defrag batch, but
 317                  * we didn't start at zero.  Make sure we loop
 318                  * around to the start of the file.
 319                  */
 320                 defrag->last_offset = 0;
 321                 defrag->cycled = 1;
 322                 btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
 323         } else {
 324                 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 325         }
 326
 327         iput(inode);
 328         return 0;
 329 cleanup:
 330         kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
 331         return ret;
 332 }
 333
 334 /*
 335  * run through the list of inodes in the FS that need
 336  * defragging
 337  */
 338 int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
 339 {
 340         struct inode_defrag *defrag;
 341         u64 first_ino = 0;
 342         u64 root_objectid = 0;
 343
 344         atomic_inc(&fs_info->defrag_running);
 345         while (1) {
 346                 /* Pause the auto defragger. */
 347                 if (test_bit(BTRFS_FS_STATE_REMOUNTING,
 348                              &fs_info->fs_state))
 349                         break;
 350
 351                 if (!__need_auto_defrag(fs_info))
 352                         break;
 353
 354                 /* find an inode to defrag */
 355                 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
 356                                                  first_ino);
 357                 if (!defrag) {
 358                         if (root_objectid || first_ino) {
 359                                 root_objectid = 0;
 360                                 first_ino = 0;
 361                                 continue;
 362                         } else {
 363                                 break;
 364                         }
 365                 }
 366
 367                 first_ino = defrag->ino + 1;
 368                 root_objectid = defrag->root;
 369
 370                 __btrfs_run_defrag_inode(fs_info, defrag);
 371         }
 372         atomic_dec(&fs_info->defrag_running);
 373
 374         /*
 375          * during unmount, we use the transaction_wait queue to
 376          * wait for the defragger to stop
 377          */
 378         wake_up(&fs_info->transaction_wait);
 379         return 0;
 380 }
 381
 382 /* simple helper to fault in pages and copy.  This should go away
 383  * and be replaced with calls into generic code.
 384  */
 385 static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
 386                                          struct page **prepared_pages,
 387                                          struct iov_iter *i)
 388 {
 389         size_t copied = 0;
 390         size_t total_copied = 0;
 391         int pg = 0;
 392         int offset = offset_in_page(pos);
 393
 394         while (write_bytes > 0) {
 395                 size_t count = min_t(size_t,
 396                                      PAGE_SIZE - offset, write_bytes);
 397                 struct page *page = prepared_pages[pg];
 398                 /*
 399                  * Copy data from userspace to the current page
 400                  */
 401                 copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
 402
 403                 /* Flush processor's dcache for this page */
 404                 flush_dcache_page(page);
 405
 406                 /*
 407                  * if we get a partial write, we can end up with
 408                  * partially up to date pages.  These add
 409                  * a lot of complexity, so make sure they don't
 410                  * happen by forcing this copy to be retried.
 411                  *
 412                  * The rest of the btrfs_file_write code will fall
 413                  * back to page at a time copies after we return 0.
 414                  */
 415                 if (!PageUptodate(page) && copied < count)
 416                         copied = 0;
 417
 418                 iov_iter_advance(i, copied);
 419                 write_bytes -= copied;
 420                 total_copied += copied;
 421
 422                 /* Return to btrfs_file_write_iter to fault page */
 423                 if (unlikely(copied == 0))
 424                         break;
 425
 426                 if (copied < PAGE_SIZE - offset) {
 427                         offset += copied;
 428                 } else {
 429                         pg++;
 430                         offset = 0;
 431                 }
 432         }
 433         return total_copied;
 434 }
 435
 436 /*
 437  * unlocks pages after btrfs_file_write is done with them
 438  */
 439 static void btrfs_drop_pages(struct page **pages, size_t num_pages)
 440 {
 441         size_t i;
 442         for (i = 0; i < num_pages; i++) {
 443                 /* page checked is some magic around finding pages that
 444                  * have been modified without going through btrfs_set_page_dirty
 445                  * clear it here. There should be no need to mark the pages
 446                  * accessed as prepare_pages should have marked them accessed
 447                  * in prepare_pages via find_or_create_page()
 448                  */
 449                 ClearPageChecked(pages[i]);
 450                 unlock_page(pages[i]);
 451                 put_page(pages[i]);
 452         }
 453 }
 454
 455 /*
 456  * After btrfs_copy_from_user(), update the following things for delalloc:
 457  * - Mark newly dirtied pages as DELALLOC in the io tree.
 458  *   Used to advise which range is to be written back.
 459  * - Mark modified pages as Uptodate/Dirty and not needing COW fixup
 460  * - Update inode size for past EOF write
 461  */
 462 int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages,
 463                       size_t num_pages, loff_t pos, size_t write_bytes,
 464                       struct extent_state **cached, bool noreserve)
 465 {
 466         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 467         int err = 0;
 468         int i;
 469         u64 num_bytes;
 470         u64 start_pos;
 471         u64 end_of_last_block;
 472         u64 end_pos = pos + write_bytes;
 473         loff_t isize = i_size_read(&inode->vfs_inode);
 474         unsigned int extra_bits = 0;
 475
 476         if (write_bytes == 0)
 477                 return 0;
 478
 479         if (noreserve)
 480                 extra_bits |= EXTENT_NORESERVE;
 481
 482         start_pos = round_down(pos, fs_info->sectorsize);
 483         num_bytes = round_up(write_bytes + pos - start_pos,
 484                              fs_info->sectorsize);
 485
 486         end_of_last_block = start_pos + num_bytes - 1;
 487
 488         /*
 489          * The pages may have already been dirty, clear out old accounting so
 490          * we can set things up properly
 491          */
 492         clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
 493                          EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
 494                          0, 0, cached);
 495
 496         err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
 497                                         extra_bits, cached);
 498         if (err)
 499                 return err;
 500
 501         for (i = 0; i < num_pages; i++) {
 502                 struct page *p = pages[i];
 503                 SetPageUptodate(p);
 504                 ClearPageChecked(p);
 505                 set_page_dirty(p);
 506         }
 507
 508         /*
 509          * we've only changed i_size in ram, and we haven't updated
 510          * the disk i_size.  There is no need to log the inode
 511          * at this time.
 512          */
 513         if (end_pos > isize)
 514                 i_size_write(&inode->vfs_inode, end_pos);
 515         return 0;
 516 }
 517
 518 /*
 519  * this drops all the extents in the cache that intersect the range
 520  * [start, end].  Existing extents are split as required.
 521  */
 522 void btrfs_drop_extent_cache(struct btrfs_inode *inode, u64 start, u64 end,
 523                              int skip_pinned)
 524 {
 525         struct extent_map *em;
 526         struct extent_map *split = NULL;
 527         struct extent_map *split2 = NULL;
 528         struct extent_map_tree *em_tree = &inode->extent_tree;
 529         u64 len = end - start + 1;
 530         u64 gen;
 531         int ret;
 532         int testend = 1;
 533         unsigned long flags;
 534         int compressed = 0;
 535         bool modified;
 536
 537         WARN_ON(end < start);
 538         if (end == (u64)-1) {
 539                 len = (u64)-1;
 540                 testend = 0;
 541         }
 542         while (1) {
 543                 int no_splits = 0;
 544
 545                 modified = false;
 546                 if (!split)
 547                         split = alloc_extent_map();
 548                 if (!split2)
 549                         split2 = alloc_extent_map();
 550                 if (!split || !split2)
 551                         no_splits = 1;
 552
 553                 write_lock(&em_tree->lock);
 554                 em = lookup_extent_mapping(em_tree, start, len);
 555                 if (!em) {
 556                         write_unlock(&em_tree->lock);
 557                         break;
 558                 }
 559                 flags = em->flags;
 560                 gen = em->generation;
 561                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
 562                         if (testend && em->start + em->len >= start + len) {
 563                                 free_extent_map(em);
 564                                 write_unlock(&em_tree->lock);
 565                                 break;
 566                         }
 567                         start = em->start + em->len;
 568                         if (testend)
 569                                 len = start + len - (em->start + em->len);
 570                         free_extent_map(em);
 571                         write_unlock(&em_tree->lock);
 572                         continue;
 573                 }
 574                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 575                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
 576                 clear_bit(EXTENT_FLAG_LOGGING, &flags);
 577                 modified = !list_empty(&em->list);
 578                 if (no_splits)
 579                         goto next;
 580
 581                 if (em->start < start) {
 582                         split->start = em->start;
 583                         split->len = start - em->start;
 584
 585                         if (em->block_start < EXTENT_MAP_LAST_BYTE) {
 586                                 split->orig_start = em->orig_start;
 587                                 split->block_start = em->block_start;
 588
 589                                 if (compressed)
 590                                         split->block_len = em->block_len;
 591                                 else
 592                                         split->block_len = split->len;
 593                                 split->orig_block_len = max(split->block_len,
 594                                                 em->orig_block_len);
 595                                 split->ram_bytes = em->ram_bytes;
 596                         } else {
 597                                 split->orig_start = split->start;
 598                                 split->block_len = 0;
 599                                 split->block_start = em->block_start;
 600                                 split->orig_block_len = 0;
 601                                 split->ram_bytes = split->len;
 602                         }
 603
 604                         split->generation = gen;
 605                         split->flags = flags;
 606                         split->compress_type = em->compress_type;
 607                         replace_extent_mapping(em_tree, em, split, modified);
 608                         free_extent_map(split);
 609                         split = split2;
 610                         split2 = NULL;
 611                 }
 612                 if (testend && em->start + em->len > start + len) {
 613                         u64 diff = start + len - em->start;
 614
 615                         split->start = start + len;
 616                         split->len = em->start + em->len - (start + len);
 617                         split->flags = flags;
 618                         split->compress_type = em->compress_type;
 619                         split->generation = gen;
 620
 621                         if (em->block_start < EXTENT_MAP_LAST_BYTE) {
 622                                 split->orig_block_len = max(em->block_len,
 623                                                     em->orig_block_len);
 624
 625                                 split->ram_bytes = em->ram_bytes;
 626                                 if (compressed) {
 627                                         split->block_len = em->block_len;
 628                                         split->block_start = em->block_start;
 629                                         split->orig_start = em->orig_start;
 630                                 } else {
 631                                         split->block_len = split->len;
 632                                         split->block_start = em->block_start
 633                                                 + diff;
 634                                         split->orig_start = em->orig_start;
 635                                 }
 636                         } else {
 637                                 split->ram_bytes = split->len;
 638                                 split->orig_start = split->start;
 639                                 split->block_len = 0;
 640                                 split->block_start = em->block_start;
 641                                 split->orig_block_len = 0;
 642                         }
 643
 644                         if (extent_map_in_tree(em)) {
 645                                 replace_extent_mapping(em_tree, em, split,
 646                                                        modified);
 647                         } else {
 648                                 ret = add_extent_mapping(em_tree, split,
 649                                                          modified);
 650                                 ASSERT(ret == 0); /* Logic error */
 651                         }
 652                         free_extent_map(split);
 653                         split = NULL;
 654                 }
 655 next:
 656                 if (extent_map_in_tree(em))
 657                         remove_extent_mapping(em_tree, em);
 658                 write_unlock(&em_tree->lock);
 659
 660                 /* once for us */
 661                 free_extent_map(em);
 662                 /* once for the tree*/
 663                 free_extent_map(em);
 664         }
 665         if (split)
 666                 free_extent_map(split);
 667         if (split2)
 668                 free_extent_map(split2);
 669 }
 670
 671 /*
 672  * this is very complex, but the basic idea is to drop all extents
 673  * in the range start - end.  hint_block is filled in with a block number
 674  * that would be a good hint to the block allocator for this file.
 675  *
 676  * If an extent intersects the range but is not entirely inside the range
 677  * it is either truncated or split.  Anything entirely inside the range
 678  * is deleted from the tree.
 679  *
 680  * Note: the VFS' inode number of bytes is not updated, it's up to the caller
 681  * to deal with that. We set the field 'bytes_found' of the arguments structure
 682  * with the number of allocated bytes found in the target range, so that the
 683  * caller can update the inode's number of bytes in an atomic way when
 684  * replacing extents in a range to avoid races with stat(2).
 685  */
 686 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
 687                        struct btrfs_root *root, struct btrfs_inode *inode,
 688                        struct btrfs_drop_extents_args *args)
 689 {
 690         struct btrfs_fs_info *fs_info = root->fs_info;
 691         struct extent_buffer *leaf;
 692         struct btrfs_file_extent_item *fi;
 693         struct btrfs_ref ref = { 0 };
 694         struct btrfs_key key;
 695         struct btrfs_key new_key;
 696         u64 ino = btrfs_ino(inode);
 697         u64 search_start = args->start;
 698         u64 disk_bytenr = 0;
 699         u64 num_bytes = 0;
 700         u64 extent_offset = 0;
 701         u64 extent_end = 0;
 702         u64 last_end = args->start;
 703         int del_nr = 0;
 704         int del_slot = 0;
 705         int extent_type;
 706         int recow;
 707         int ret;
 708         int modify_tree = -1;
 709         int update_refs;
 710         int found = 0;
 711         int leafs_visited = 0;
 712         struct btrfs_path *path = args->path;
 713
 714         args->bytes_found = 0;
 715         args->extent_inserted = false;
 716
 717         /* Must always have a path if ->replace_extent is true */
 718         ASSERT(!(args->replace_extent && !args->path));
 719
 720         if (!path) {
 721                 path = btrfs_alloc_path();
 722                 if (!path) {
 723                         ret = -ENOMEM;
 724                         goto out;
 725                 }
 726         }
 727
 728         if (args->drop_cache)
 729                 btrfs_drop_extent_cache(inode, args->start, args->end - 1, 0);
 730
 731         if (args->start >= inode->disk_i_size && !args->replace_extent)
 732                 modify_tree = 0;
 733
 734         update_refs = (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
 735                        root == fs_info->tree_root);
 736         while (1) {
 737                 recow = 0;
 738                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
 739                                                search_start, modify_tree);
 740                 if (ret < 0)
 741                         break;
 742                 if (ret > 0 && path->slots[0] > 0 && search_start == args->start) {
 743                         leaf = path->nodes[0];
 744                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
 745                         if (key.objectid == ino &&
 746                             key.type == BTRFS_EXTENT_DATA_KEY)
 747                                 path->slots[0]--;
 748                 }
 749                 ret = 0;
 750                 leafs_visited++;
 751 next_slot:
 752                 leaf = path->nodes[0];
 753                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 754                         BUG_ON(del_nr > 0);
 755                         ret = btrfs_next_leaf(root, path);
 756                         if (ret < 0)
 757                                 break;
 758                         if (ret > 0) {
 759                                 ret = 0;
 760                                 break;
 761                         }
 762                         leafs_visited++;
 763                         leaf = path->nodes[0];
 764                         recow = 1;
 765                 }
 766
 767                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 768
 769                 if (key.objectid > ino)
 770                         break;
 771                 if (WARN_ON_ONCE(key.objectid < ino) ||
 772                     key.type < BTRFS_EXTENT_DATA_KEY) {
 773                         ASSERT(del_nr == 0);
 774                         path->slots[0]++;
 775                         goto next_slot;
 776                 }
 777                 if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end)
 778                         break;
 779
 780                 fi = btrfs_item_ptr(leaf, path->slots[0],
 781                                     struct btrfs_file_extent_item);
 782                 extent_type = btrfs_file_extent_type(leaf, fi);
 783
 784                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
 785                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
 786                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
 787                         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
 788                         extent_offset = btrfs_file_extent_offset(leaf, fi);
 789                         extent_end = key.offset +
 790                                 btrfs_file_extent_num_bytes(leaf, fi);
 791                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 792                         extent_end = key.offset +
 793                                 btrfs_file_extent_ram_bytes(leaf, fi);
 794                 } else {
 795                         /* can't happen */
 796                         BUG();
 797                 }
 798
 799                 /*
 800                  * Don't skip extent items representing 0 byte lengths. They
 801                  * used to be created (bug) if while punching holes we hit
 802                  * -ENOSPC condition. So if we find one here, just ensure we
 803                  * delete it, otherwise we would insert a new file extent item
 804                  * with the same key (offset) as that 0 bytes length file
 805                  * extent item in the call to setup_items_for_insert() later
 806                  * in this function.
 807                  */
 808                 if (extent_end == key.offset && extent_end >= search_start) {
 809                         last_end = extent_end;
 810                         goto delete_extent_item;
 811                 }
 812
 813                 if (extent_end <= search_start) {
 814                         path->slots[0]++;
 815                         goto next_slot;
 816                 }
 817
 818                 found = 1;
 819                 search_start = max(key.offset, args->start);
 820                 if (recow || !modify_tree) {
 821                         modify_tree = -1;
 822                         btrfs_release_path(path);
 823                         continue;
 824                 }
 825
 826                 /*
 827                  *     | - range to drop - |
 828                  *  | -------- extent -------- |
 829                  */
 830                 if (args->start > key.offset && args->end < extent_end) {
 831                         BUG_ON(del_nr > 0);
 832                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 833                                 ret = -EOPNOTSUPP;
 834                                 break;
 835                         }
 836
 837                         memcpy(&new_key, &key, sizeof(new_key));
 838                         new_key.offset = args->start;
 839                         ret = btrfs_duplicate_item(trans, root, path,
 840                                                    &new_key);
 841                         if (ret == -EAGAIN) {
 842                                 btrfs_release_path(path);
 843                                 continue;
 844                         }
 845                         if (ret < 0)
 846                                 break;
 847
 848                         leaf = path->nodes[0];
 849                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
 850                                             struct btrfs_file_extent_item);
 851                         btrfs_set_file_extent_num_bytes(leaf, fi,
 852                                                         args->start - key.offset);
 853
 854                         fi = btrfs_item_ptr(leaf, path->slots[0],
 855                                             struct btrfs_file_extent_item);
 856
 857                         extent_offset += args->start - key.offset;
 858                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 859                         btrfs_set_file_extent_num_bytes(leaf, fi,
 860                                                         extent_end - args->start);
 861                         btrfs_mark_buffer_dirty(leaf);
 862
 863                         if (update_refs && disk_bytenr > 0) {
 864                                 btrfs_init_generic_ref(&ref,
 865                                                 BTRFS_ADD_DELAYED_REF,
 866                                                 disk_bytenr, num_bytes, 0);
 867                                 btrfs_init_data_ref(&ref,
 868                                                 root->root_key.objectid,
 869                                                 new_key.objectid,
 870                                                 args->start - extent_offset);
 871                                 ret = btrfs_inc_extent_ref(trans, &ref);
 872                                 BUG_ON(ret); /* -ENOMEM */
 873                         }
 874                         key.offset = args->start;
 875                 }
 876                 /*
 877                  * From here on out we will have actually dropped something, so
 878                  * last_end can be updated.
 879                  */
 880                 last_end = extent_end;
 881
 882                 /*
 883                  *  | ---- range to drop ----- |
 884                  *      | -------- extent -------- |
 885                  */
 886                 if (args->start <= key.offset && args->end < extent_end) {
 887                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 888                                 ret = -EOPNOTSUPP;
 889                                 break;
 890                         }
 891
 892                         memcpy(&new_key, &key, sizeof(new_key));
 893                         new_key.offset = args->end;
 894                         btrfs_set_item_key_safe(fs_info, path, &new_key);
 895
 896                         extent_offset += args->end - key.offset;
 897                         btrfs_set_file_extent_offset(leaf, fi, extent_offset);
 898                         btrfs_set_file_extent_num_bytes(leaf, fi,
 899                                                         extent_end - args->end);
 900                         btrfs_mark_buffer_dirty(leaf);
 901                         if (update_refs && disk_bytenr > 0)
 902                                 args->bytes_found += args->end - key.offset;
 903                         break;
 904                 }
 905
 906                 search_start = extent_end;
 907                 /*
 908                  *       | ---- range to drop ----- |
 909                  *  | -------- extent -------- |
 910                  */
 911                 if (args->start > key.offset && args->end >= extent_end) {
 912                         BUG_ON(del_nr > 0);
 913                         if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 914                                 ret = -EOPNOTSUPP;
 915                                 break;
 916                         }
 917
 918                         btrfs_set_file_extent_num_bytes(leaf, fi,
 919                                                         args->start - key.offset);
 920                         btrfs_mark_buffer_dirty(leaf);
 921                         if (update_refs && disk_bytenr > 0)
 922                                 args->bytes_found += extent_end - args->start;
 923                         if (args->end == extent_end)
 924                                 break;
 925
 926                         path->slots[0]++;
 927                         goto next_slot;
 928                 }
 929
 930                 /*
 931                  *  | ---- range to drop ----- |
 932                  *    | ------ extent ------ |
 933                  */
 934                 if (args->start <= key.offset && args->end >= extent_end) {
 935 delete_extent_item:
 936                         if (del_nr == 0) {
 937                                 del_slot = path->slots[0];
 938                                 del_nr = 1;
 939                         } else {
 940                                 BUG_ON(del_slot + del_nr != path->slots[0]);
 941                                 del_nr++;
 942                         }
 943
 944                         if (update_refs &&
 945                             extent_type == BTRFS_FILE_EXTENT_INLINE) {
 946                                 args->bytes_found += extent_end - key.offset;
 947                                 extent_end = ALIGN(extent_end,
 948                                                    fs_info->sectorsize);
 949                         } else if (update_refs && disk_bytenr > 0) {
 950                                 btrfs_init_generic_ref(&ref,
 951                                                 BTRFS_DROP_DELAYED_REF,
 952                                                 disk_bytenr, num_bytes, 0);
 953                                 btrfs_init_data_ref(&ref,
 954                                                 root->root_key.objectid,
 955                                                 key.objectid,
 956                                                 key.offset - extent_offset);
 957                                 ret = btrfs_free_extent(trans, &ref);
 958                                 BUG_ON(ret); /* -ENOMEM */
 959                                 args->bytes_found += extent_end - key.offset;
 960                         }
 961
 962                         if (args->end == extent_end)
 963                                 break;
 964
 965                         if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
 966                                 path->slots[0]++;
 967                                 goto next_slot;
 968                         }
 969
 970                         ret = btrfs_del_items(trans, root, path, del_slot,
 971                                               del_nr);
 972                         if (ret) {
 973                                 btrfs_abort_transaction(trans, ret);
 974                                 break;
 975                         }
 976
 977                         del_nr = 0;
 978                         del_slot = 0;
 979
 980                         btrfs_release_path(path);
 981                         continue;
 982                 }
 983
 984                 BUG();
 985         }
 986
 987         if (!ret && del_nr > 0) {
 988                 /*
 989                  * Set path->slots[0] to first slot, so that after the delete
 990                  * if items are move off from our leaf to its immediate left or
 991                  * right neighbor leafs, we end up with a correct and adjusted
 992                  * path->slots[0] for our insertion (if args->replace_extent).
 993                  */
 994                 path->slots[0] = del_slot;
 995                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
 996                 if (ret)
 997                         btrfs_abort_transaction(trans, ret);
 998         }
 999
1000         leaf = path->nodes[0];
1001         /*
1002          * If btrfs_del_items() was called, it might have deleted a leaf, in
1003          * which case it unlocked our path, so check path->locks[0] matches a
1004          * write lock.
1005          */
1006         if (!ret && args->replace_extent && leafs_visited == 1 &&
1007             path->locks[0] == BTRFS_WRITE_LOCK &&
1008             btrfs_leaf_free_space(leaf) >=
1009             sizeof(struct btrfs_item) + args->extent_item_size) {
1010
1011                 key.objectid = ino;
1012                 key.type = BTRFS_EXTENT_DATA_KEY;
1013                 key.offset = args->start;
1014                 if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
1015                         struct btrfs_key slot_key;
1016
1017                         btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
1018                         if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
1019                                 path->slots[0]++;
1020                 }
1021                 setup_items_for_insert(root, path, &key,
1022                                        &args->extent_item_size, 1);
1023                 args->extent_inserted = true;
1024         }
1025
1026         if (!args->path)
1027                 btrfs_free_path(path);
1028         else if (!args->extent_inserted)
1029                 btrfs_release_path(path);
1030 out:
1031         args->drop_end = found ? min(args->end, last_end) : args->end;
1032
1033         return ret;
1034 }
1035
1036 static int extent_mergeable(struct extent_buffer *leaf, int slot,
1037                             u64 objectid, u64 bytenr, u64 orig_offset,
1038                             u64 *start, u64 *end)
1039 {
1040         struct btrfs_file_extent_item *fi;
1041         struct btrfs_key key;
1042         u64 extent_end;
1043
1044         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
1045                 return 0;
1046
1047         btrfs_item_key_to_cpu(leaf, &key, slot);
1048         if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
1049                 return 0;
1050
1051         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
1052         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
1053             btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
1054             btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
1055             btrfs_file_extent_compression(leaf, fi) ||
1056             btrfs_file_extent_encryption(leaf, fi) ||
1057             btrfs_file_extent_other_encoding(leaf, fi))
1058                 return 0;
1059
1060         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1061         if ((*start && *start != key.offset) || (*end && *end != extent_end))
1062                 return 0;
1063
1064         *start = key.offset;
1065         *end = extent_end;
1066         return 1;
1067 }
1068
1069 /*
1070  * Mark extent in the range start - end as written.
1071  *
1072  * This changes extent type from 'pre-allocated' to 'regular'. If only
1073  * part of extent is marked as written, the extent will be split into
1074  * two or three.
1075  */
1076 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
1077                               struct btrfs_inode *inode, u64 start, u64 end)
1078 {
1079         struct btrfs_fs_info *fs_info = trans->fs_info;
1080         struct btrfs_root *root = inode->root;
1081         struct extent_buffer *leaf;
1082         struct btrfs_path *path;
1083         struct btrfs_file_extent_item *fi;
1084         struct btrfs_ref ref = { 0 };
1085         struct btrfs_key key;
1086         struct btrfs_key new_key;
1087         u64 bytenr;
1088         u64 num_bytes;
1089         u64 extent_end;
1090         u64 orig_offset;
1091         u64 other_start;
1092         u64 other_end;
1093         u64 split;
1094         int del_nr = 0;
1095         int del_slot = 0;
1096         int recow;
1097         int ret;
1098         u64 ino = btrfs_ino(inode);
1099
1100         path = btrfs_alloc_path();
1101         if (!path)
1102                 return -ENOMEM;
1103 again:
1104         recow = 0;
1105         split = start;
1106         key.objectid = ino;
1107         key.type = BTRFS_EXTENT_DATA_KEY;
1108         key.offset = split;
1109
1110         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1111         if (ret < 0)
1112                 goto out;
1113         if (ret > 0 && path->slots[0] > 0)
1114                 path->slots[0]--;
1115
1116         leaf = path->nodes[0];
1117         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1118         if (key.objectid != ino ||
1119             key.type != BTRFS_EXTENT_DATA_KEY) {
1120                 ret = -EINVAL;
1121                 btrfs_abort_transaction(trans, ret);
1122                 goto out;
1123         }
1124         fi = btrfs_item_ptr(leaf, path->slots[0],
1125                             struct btrfs_file_extent_item);
1126         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
1127                 ret = -EINVAL;
1128                 btrfs_abort_transaction(trans, ret);
1129                 goto out;
1130         }
1131         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
1132         if (key.offset > start || extent_end < end) {
1133                 ret = -EINVAL;
1134                 btrfs_abort_transaction(trans, ret);
1135                 goto out;
1136         }
1137
1138         bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1139         num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1140         orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
1141         memcpy(&new_key, &key, sizeof(new_key));
1142
1143         if (start == key.offset && end < extent_end) {
1144                 other_start = 0;
1145                 other_end = start;
1146                 if (extent_mergeable(leaf, path->slots[0] - 1,
1147                                      ino, bytenr, orig_offset,
1148                                      &other_start, &other_end)) {
1149                         new_key.offset = end;
1150                         btrfs_set_item_key_safe(fs_info, path, &new_key);
1151                         fi = btrfs_item_ptr(leaf, path->slots[0],
1152                                             struct btrfs_file_extent_item);
1153                         btrfs_set_file_extent_generation(leaf, fi,
1154                                                          trans->transid);
1155                         btrfs_set_file_extent_num_bytes(leaf, fi,
1156                                                         extent_end - end);
1157                         btrfs_set_file_extent_offset(leaf, fi,
1158                                                      end - orig_offset);
1159                         fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1160                                             struct btrfs_file_extent_item);
1161                         btrfs_set_file_extent_generation(leaf, fi,
1162                                                          trans->transid);
1163                         btrfs_set_file_extent_num_bytes(leaf, fi,
1164                                                         end - other_start);
1165                         btrfs_mark_buffer_dirty(leaf);
1166                         goto out;
1167                 }
1168         }
1169
1170         if (start > key.offset && end == extent_end) {
1171                 other_start = end;
1172                 other_end = 0;
1173                 if (extent_mergeable(leaf, path->slots[0] + 1,
1174                                      ino, bytenr, orig_offset,
1175                                      &other_start, &other_end)) {
1176                         fi = btrfs_item_ptr(leaf, path->slots[0],
1177                                             struct btrfs_file_extent_item);
1178                         btrfs_set_file_extent_num_bytes(leaf, fi,
1179                                                         start - key.offset);
1180                         btrfs_set_file_extent_generation(leaf, fi,
1181                                                          trans->transid);
1182                         path->slots[0]++;
1183                         new_key.offset = start;
1184                         btrfs_set_item_key_safe(fs_info, path, &new_key);
1185
1186                         fi = btrfs_item_ptr(leaf, path->slots[0],
1187                                             struct btrfs_file_extent_item);
1188                         btrfs_set_file_extent_generation(leaf, fi,
1189                                                          trans->transid);
1190                         btrfs_set_file_extent_num_bytes(leaf, fi,
1191                                                         other_end - start);
1192                         btrfs_set_file_extent_offset(leaf, fi,
1193                                                      start - orig_offset);
1194                         btrfs_mark_buffer_dirty(leaf);
1195                         goto out;
1196                 }
1197         }
1198
1199         while (start > key.offset || end < extent_end) {
1200                 if (key.offset == start)
1201                         split = end;
1202
1203                 new_key.offset = split;
1204                 ret = btrfs_duplicate_item(trans, root, path, &new_key);
1205                 if (ret == -EAGAIN) {
1206                         btrfs_release_path(path);
1207                         goto again;
1208                 }
1209                 if (ret < 0) {
1210                         btrfs_abort_transaction(trans, ret);
1211                         goto out;
1212                 }
1213
1214                 leaf = path->nodes[0];
1215                 fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
1216                                     struct btrfs_file_extent_item);
1217                 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1218                 btrfs_set_file_extent_num_bytes(leaf, fi,
1219                                                 split - key.offset);
1220
1221                 fi = btrfs_item_ptr(leaf, path->slots[0],
1222                                     struct btrfs_file_extent_item);
1223
1224                 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1225                 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
1226                 btrfs_set_file_extent_num_bytes(leaf, fi,
1227                                                 extent_end - split);
1228                 btrfs_mark_buffer_dirty(leaf);
1229
1230                 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr,
1231                                        num_bytes, 0);
1232                 btrfs_init_data_ref(&ref, root->root_key.objectid, ino,
1233                                     orig_offset);
1234                 ret = btrfs_inc_extent_ref(trans, &ref);
1235                 if (ret) {
1236                         btrfs_abort_transaction(trans, ret);
1237                         goto out;
1238                 }
1239
1240                 if (split == start) {
1241                         key.offset = start;
1242                 } else {
1243                         if (start != key.offset) {
1244                                 ret = -EINVAL;
1245                                 btrfs_abort_transaction(trans, ret);
1246                                 goto out;
1247                         }
1248                         path->slots[0]--;
1249                         extent_end = end;
1250                 }
1251                 recow = 1;
1252         }
1253
1254         other_start = end;
1255         other_end = 0;
1256         btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1257                                num_bytes, 0);
1258         btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset);
1259         if (extent_mergeable(leaf, path->slots[0] + 1,
1260                              ino, bytenr, orig_offset,
1261                              &other_start, &other_end)) {
1262                 if (recow) {
1263                         btrfs_release_path(path);
1264                         goto again;
1265                 }
1266                 extent_end = other_end;
1267                 del_slot = path->slots[0] + 1;
1268                 del_nr++;
1269                 ret = btrfs_free_extent(trans, &ref);
1270                 if (ret) {
1271                         btrfs_abort_transaction(trans, ret);
1272                         goto out;
1273                 }
1274         }
1275         other_start = 0;
1276         other_end = start;
1277         if (extent_mergeable(leaf, path->slots[0] - 1,
1278                              ino, bytenr, orig_offset,
1279                              &other_start, &other_end)) {
1280                 if (recow) {
1281                         btrfs_release_path(path);
1282                         goto again;
1283                 }
1284                 key.offset = other_start;
1285                 del_slot = path->slots[0];
1286                 del_nr++;
1287                 ret = btrfs_free_extent(trans, &ref);
1288                 if (ret) {
1289                         btrfs_abort_transaction(trans, ret);
1290                         goto out;
1291                 }
1292         }
1293         if (del_nr == 0) {
1294                 fi = btrfs_item_ptr(leaf, path->slots[0],
1295                            struct btrfs_file_extent_item);
1296                 btrfs_set_file_extent_type(leaf, fi,
1297                                            BTRFS_FILE_EXTENT_REG);
1298                 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1299                 btrfs_mark_buffer_dirty(leaf);
1300         } else {
1301                 fi = btrfs_item_ptr(leaf, del_slot - 1,
1302                            struct btrfs_file_extent_item);
1303                 btrfs_set_file_extent_type(leaf, fi,
1304                                            BTRFS_FILE_EXTENT_REG);
1305                 btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1306                 btrfs_set_file_extent_num_bytes(leaf, fi,
1307                                                 extent_end - key.offset);
1308                 btrfs_mark_buffer_dirty(leaf);
1309
1310                 ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
1311                 if (ret < 0) {
1312                         btrfs_abort_transaction(trans, ret);
1313                         goto out;
1314                 }
1315         }
1316 out:
1317         btrfs_free_path(path);
1318         return 0;
1319 }
1320
1321 /*
1322  * on error we return an unlocked page and the error value
1323  * on success we return a locked page and 0
1324  */
1325 static int prepare_uptodate_page(struct inode *inode,
1326                                  struct page *page, u64 pos,
1327                                  bool force_uptodate)
1328 {
1329         int ret = 0;
1330
1331         if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
1332             !PageUptodate(page)) {
1333                 ret = btrfs_readpage(NULL, page);
1334                 if (ret)
1335                         return ret;
1336                 lock_page(page);
1337                 if (!PageUptodate(page)) {
1338                         unlock_page(page);
1339                         return -EIO;
1340                 }
1341                 if (page->mapping != inode->i_mapping) {
1342                         unlock_page(page);
1343                         return -EAGAIN;
1344                 }
1345         }
1346         return 0;
1347 }
1348
1349 /*
1350  * this just gets pages into the page cache and locks them down.
1351  */
1352 static noinline int prepare_pages(struct inode *inode, struct page **pages,
1353                                   size_t num_pages, loff_t pos,
1354                                   size_t write_bytes, bool force_uptodate)
1355 {
1356         int i;
1357         unsigned long index = pos >> PAGE_SHIFT;
1358         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1359         int err = 0;
1360         int faili;
1361
1362         for (i = 0; i < num_pages; i++) {
1363 again:
1364                 pages[i] = find_or_create_page(inode->i_mapping, index + i,
1365                                                mask | __GFP_WRITE);
1366                 if (!pages[i]) {
1367                         faili = i - 1;
1368                         err = -ENOMEM;
1369                         goto fail;
1370                 }
1371
1372                 err = set_page_extent_mapped(pages[i]);
1373                 if (err < 0) {
1374                         faili = i;
1375                         goto fail;
1376                 }
1377
1378                 if (i == 0)
1379                         err = prepare_uptodate_page(inode, pages[i], pos,
1380                                                     force_uptodate);
1381                 if (!err && i == num_pages - 1)
1382                         err = prepare_uptodate_page(inode, pages[i],
1383                                                     pos + write_bytes, false);
1384                 if (err) {
1385                         put_page(pages[i]);
1386                         if (err == -EAGAIN) {
1387                                 err = 0;
1388                                 goto again;
1389                         }
1390                         faili = i - 1;
1391                         goto fail;
1392                 }
1393                 wait_on_page_writeback(pages[i]);
1394         }
1395
1396         return 0;
1397 fail:
1398         while (faili >= 0) {
1399                 unlock_page(pages[faili]);
1400                 put_page(pages[faili]);
1401                 faili--;
1402         }
1403         return err;
1404
1405 }
1406
1407 /*
1408  * This function locks the extent and properly waits for data=ordered extents
1409  * to finish before allowing the pages to be modified if need.
1410  *
1411  * The return value:
1412  * 1 - the extent is locked
1413  * 0 - the extent is not locked, and everything is OK
1414  * -EAGAIN - need re-prepare the pages
1415  * the other < 0 number - Something wrong happens
1416  */
1417 static noinline int
1418 lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
1419                                 size_t num_pages, loff_t pos,
1420                                 size_t write_bytes,
1421                                 u64 *lockstart, u64 *lockend,
1422                                 struct extent_state **cached_state)
1423 {
1424         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1425         u64 start_pos;
1426         u64 last_pos;
1427         int i;
1428         int ret = 0;
1429
1430         start_pos = round_down(pos, fs_info->sectorsize);
1431         last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1;
1432
1433         if (start_pos < inode->vfs_inode.i_size) {
1434                 struct btrfs_ordered_extent *ordered;
1435
1436                 lock_extent_bits(&inode->io_tree, start_pos, last_pos,
1437                                 cached_state);
1438                 ordered = btrfs_lookup_ordered_range(inode, start_pos,
1439                                                      last_pos - start_pos + 1);
1440                 if (ordered &&
1441                     ordered->file_offset + ordered->num_bytes > start_pos &&
1442                     ordered->file_offset <= last_pos) {
1443                         unlock_extent_cached(&inode->io_tree, start_pos,
1444                                         last_pos, cached_state);
1445                         for (i = 0; i < num_pages; i++) {
1446                                 unlock_page(pages[i]);
1447                                 put_page(pages[i]);
1448                         }
1449                         btrfs_start_ordered_extent(ordered, 1);
1450                         btrfs_put_ordered_extent(ordered);
1451                         return -EAGAIN;
1452                 }
1453                 if (ordered)
1454                         btrfs_put_ordered_extent(ordered);
1455
1456                 *lockstart = start_pos;
1457                 *lockend = last_pos;
1458                 ret = 1;
1459         }
1460
1461         /*
1462          * We should be called after prepare_pages() which should have locked
1463          * all pages in the range.
1464          */
1465         for (i = 0; i < num_pages; i++)
1466                 WARN_ON(!PageLocked(pages[i]));
1467
1468         return ret;
1469 }
1470
1471 static int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
1472                            size_t *write_bytes, bool nowait)
1473 {
1474         struct btrfs_fs_info *fs_info = inode->root->fs_info;
1475         struct btrfs_root *root = inode->root;
1476         u64 lockstart, lockend;
1477         u64 num_bytes;
1478         int ret;
1479
1480         if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC)))
1481                 return 0;
1482
1483         if (!nowait && !btrfs_drew_try_write_lock(&root->snapshot_lock))
1484                 return -EAGAIN;
1485
1486         lockstart = round_down(pos, fs_info->sectorsize);
1487         lockend = round_up(pos + *write_bytes,
1488                            fs_info->sectorsize) - 1;
1489         num_bytes = lockend - lockstart + 1;
1490
1491         if (nowait) {
1492                 struct btrfs_ordered_extent *ordered;
1493
1494                 if (!try_lock_extent(&inode->io_tree, lockstart, lockend))
1495                         return -EAGAIN;
1496
1497                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
1498                                                      num_bytes);
1499                 if (ordered) {
1500                         btrfs_put_ordered_extent(ordered);
1501                         ret = -EAGAIN;
1502                         goto out_unlock;
1503                 }
1504         } else {
1505                 btrfs_lock_and_flush_ordered_range(inode, lockstart,
1506                                                    lockend, NULL);
1507         }
1508
1509         ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
1510                         NULL, NULL, NULL, false);
1511         if (ret <= 0) {
1512                 ret = 0;
1513                 if (!nowait)
1514                         btrfs_drew_write_unlock(&root->snapshot_lock);
1515         } else {
1516                 *write_bytes = min_t(size_t, *write_bytes ,
1517                                      num_bytes - pos + lockstart);
1518         }
1519 out_unlock:
1520         unlock_extent(&inode->io_tree, lockstart, lockend);
1521
1522         return ret;
1523 }
1524
1525 static int check_nocow_nolock(struct btrfs_inode *inode, loff_t pos,
1526                               size_t *write_bytes)
1527 {
1528         return check_can_nocow(inode, pos, write_bytes, true);
1529 }
1530
1531 /*
1532  * Check if we can do nocow write into the range [@pos, @pos + @write_bytes)
1533  *
1534  * @pos:         File offset
1535  * @write_bytes: The length to write, will be updated to the nocow writeable
1536  *               range
1537  *
1538  * This function will flush ordered extents in the range to ensure proper
1539  * nocow checks.
1540  *
1541  * Return:
1542  * >0           and update @write_bytes if we can do nocow write
1543  *  0           if we can't do nocow write
1544  * -EAGAIN      if we can't get the needed lock or there are ordered extents
1545  *              for * (nowait == true) case
1546  * <0           if other error happened
1547  *
1548  * NOTE: Callers need to release the lock by btrfs_check_nocow_unlock().
1549  */
1550 int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
1551                            size_t *write_bytes)
1552 {
1553         return check_can_nocow(inode, pos, write_bytes, false);
1554 }
1555
1556 void btrfs_check_nocow_unlock(struct btrfs_inode *inode)
1557 {
1558         btrfs_drew_write_unlock(&inode->root->snapshot_lock);
1559 }
1560
1561 static void update_time_for_write(struct inode *inode)
1562 {
1563         struct timespec64 now;
1564
1565         if (IS_NOCMTIME(inode))
1566                 return;
1567
1568         now = current_time(inode);
1569         if (!timespec64_equal(&inode->i_mtime, &now))
1570                 inode->i_mtime = now;
1571
1572         if (!timespec64_equal(&inode->i_ctime, &now))
1573                 inode->i_ctime = now;
1574
1575         if (IS_I_VERSION(inode))
1576                 inode_inc_iversion(inode);
1577 }
1578
1579 static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from,
1580                              size_t count)
1581 {
1582         struct file *file = iocb->ki_filp;
1583         struct inode *inode = file_inode(file);
1584         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1585         loff_t pos = iocb->ki_pos;
1586         int ret;
1587         loff_t oldsize;
1588         loff_t start_pos;
1589
1590         if (iocb->ki_flags & IOCB_NOWAIT) {
1591                 size_t nocow_bytes = count;
1592
1593                 /* We will allocate space in case nodatacow is not set, so bail */
1594                 if (check_nocow_nolock(BTRFS_I(inode), pos, &nocow_bytes) <= 0)
1595                         return -EAGAIN;
1596                 /*
1597                  * There are holes in the range or parts of the range that must
1598                  * be COWed (shared extents, RO block groups, etc), so just bail
1599                  * out.
1600                  */
1601                 if (nocow_bytes < count)
1602                         return -EAGAIN;
1603         }
1604
1605         current->backing_dev_info = inode_to_bdi(inode);
1606         ret = file_remove_privs(file);
1607         if (ret)
1608                 return ret;
1609
1610         /*
1611          * We reserve space for updating the inode when we reserve space for the
1612          * extent we are going to write, so we will enospc out there.  We don't
1613          * need to start yet another transaction to update the inode as we will
1614          * update the inode when we finish writing whatever data we write.
1615          */
1616         update_time_for_write(inode);
1617
1618         start_pos = round_down(pos, fs_info->sectorsize);
1619         oldsize = i_size_read(inode);
1620         if (start_pos > oldsize) {
1621                 /* Expand hole size to cover write data, preventing empty gap */
1622                 loff_t end_pos = round_up(pos + count, fs_info->sectorsize);
1623
1624                 ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos);
1625                 if (ret) {
1626                         current->backing_dev_info = NULL;
1627                         return ret;
1628                 }
1629         }
1630
1631         return 0;
1632 }
1633
1634 static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
1635                                                struct iov_iter *i)
1636 {
1637         struct file *file = iocb->ki_filp;
1638         loff_t pos;
1639         struct inode *inode = file_inode(file);
1640         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1641         struct page **pages = NULL;
1642         struct extent_changeset *data_reserved = NULL;
1643         u64 release_bytes = 0;
1644         u64 lockstart;
1645         u64 lockend;
1646         size_t num_written = 0;
1647         int nrptrs;
1648         ssize_t ret;
1649         bool only_release_metadata = false;
1650         bool force_page_uptodate = false;
1651         loff_t old_isize = i_size_read(inode);
1652         unsigned int ilock_flags = 0;
1653
1654         if (iocb->ki_flags & IOCB_NOWAIT)
1655                 ilock_flags |= BTRFS_ILOCK_TRY;
1656
1657         ret = btrfs_inode_lock(inode, ilock_flags);
1658         if (ret < 0)
1659                 return ret;
1660
1661         ret = generic_write_checks(iocb, i);
1662         if (ret <= 0)
1663                 goto out;
1664
1665         ret = btrfs_write_check(iocb, i, ret);
1666         if (ret < 0)
1667                 goto out;
1668
1669         pos = iocb->ki_pos;
1670         nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
1671                         PAGE_SIZE / (sizeof(struct page *)));
1672         nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
1673         nrptrs = max(nrptrs, 8);
1674         pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
1675         if (!pages) {
1676                 ret = -ENOMEM;
1677                 goto out;
1678         }
1679
1680         while (iov_iter_count(i) > 0) {
1681                 struct extent_state *cached_state = NULL;
1682                 size_t offset = offset_in_page(pos);
1683                 size_t sector_offset;
1684                 size_t write_bytes = min(iov_iter_count(i),
1685                                          nrptrs * (size_t)PAGE_SIZE -
1686                                          offset);
1687                 size_t num_pages;
1688                 size_t reserve_bytes;
1689                 size_t dirty_pages;
1690                 size_t copied;
1691                 size_t dirty_sectors;
1692                 size_t num_sectors;
1693                 int extents_locked;
1694
1695                 /*
1696                  * Fault pages before locking them in prepare_pages
1697                  * to avoid recursive lock
1698                  */
1699                 if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
1700                         ret = -EFAULT;
1701                         break;
1702                 }
1703
1704                 only_release_metadata = false;
1705                 sector_offset = pos & (fs_info->sectorsize - 1);
1706
1707                 extent_changeset_release(data_reserved);
1708                 ret = btrfs_check_data_free_space(BTRFS_I(inode),
1709                                                   &data_reserved, pos,
1710                                                   write_bytes);
1711                 if (ret < 0) {
1712                         /*
1713                          * If we don't have to COW at the offset, reserve
1714                          * metadata only. write_bytes may get smaller than
1715                          * requested here.
1716                          */
1717                         if (btrfs_check_nocow_lock(BTRFS_I(inode), pos,
1718                                                    &write_bytes) > 0)
1719                                 only_release_metadata = true;
1720                         else
1721                                 break;
1722                 }
1723
1724                 num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE);
1725                 WARN_ON(num_pages > nrptrs);
1726                 reserve_bytes = round_up(write_bytes + sector_offset,
1727                                          fs_info->sectorsize);
1728                 WARN_ON(reserve_bytes == 0);
1729                 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
1730                                 reserve_bytes);
1731                 if (ret) {
1732                         if (!only_release_metadata)
1733                                 btrfs_free_reserved_data_space(BTRFS_I(inode),
1734                                                 data_reserved, pos,
1735                                                 write_bytes);
1736                         else
1737                                 btrfs_check_nocow_unlock(BTRFS_I(inode));
1738                         break;
1739                 }
1740
1741                 release_bytes = reserve_bytes;
1742 again:
1743                 /*
1744                  * This is going to setup the pages array with the number of
1745                  * pages we want, so we don't really need to worry about the
1746                  * contents of pages from loop to loop
1747                  */
1748                 ret = prepare_pages(inode, pages, num_pages,
1749                                     pos, write_bytes,
1750                                     force_page_uptodate);
1751                 if (ret) {
1752                         btrfs_delalloc_release_extents(BTRFS_I(inode),
1753                                                        reserve_bytes);
1754                         break;
1755                 }
1756
1757                 extents_locked = lock_and_cleanup_extent_if_need(
1758                                 BTRFS_I(inode), pages,
1759                                 num_pages, pos, write_bytes, &lockstart,
1760                                 &lockend, &cached_state);
1761                 if (extents_locked < 0) {
1762                         if (extents_locked == -EAGAIN)
1763                                 goto again;
1764                         btrfs_delalloc_release_extents(BTRFS_I(inode),
1765                                                        reserve_bytes);
1766                         ret = extents_locked;
1767                         break;
1768                 }
1769
1770                 copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
1771
1772                 num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
1773                 dirty_sectors = round_up(copied + sector_offset,
1774                                         fs_info->sectorsize);
1775                 dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
1776
1777                 /*
1778                  * if we have trouble faulting in the pages, fall
1779                  * back to one page at a time
1780                  */
1781                 if (copied < write_bytes)
1782                         nrptrs = 1;
1783
1784                 if (copied == 0) {
1785                         force_page_uptodate = true;
1786                         dirty_sectors = 0;
1787                         dirty_pages = 0;
1788                 } else {
1789                         force_page_uptodate = false;
1790                         dirty_pages = DIV_ROUND_UP(copied + offset,
1791                                                    PAGE_SIZE);
1792                 }
1793
1794                 if (num_sectors > dirty_sectors) {
1795                         /* release everything except the sectors we dirtied */
1796                         release_bytes -= dirty_sectors << fs_info->sectorsize_bits;
1797                         if (only_release_metadata) {
1798                                 btrfs_delalloc_release_metadata(BTRFS_I(inode),
1799                                                         release_bytes, true);
1800                         } else {
1801                                 u64 __pos;
1802
1803                                 __pos = round_down(pos,
1804                                                    fs_info->sectorsize) +
1805                                         (dirty_pages << PAGE_SHIFT);
1806                                 btrfs_delalloc_release_space(BTRFS_I(inode),
1807                                                 data_reserved, __pos,
1808                                                 release_bytes, true);
1809                         }
1810                 }
1811
1812                 release_bytes = round_up(copied + sector_offset,
1813                                         fs_info->sectorsize);
1814
1815                 ret = btrfs_dirty_pages(BTRFS_I(inode), pages,
1816                                         dirty_pages, pos, copied,
1817                                         &cached_state, only_release_metadata);
1818
1819                 /*
1820                  * If we have not locked the extent range, because the range's
1821                  * start offset is >= i_size, we might still have a non-NULL
1822                  * cached extent state, acquired while marking the extent range
1823                  * as delalloc through btrfs_dirty_pages(). Therefore free any
1824                  * possible cached extent state to avoid a memory leak.
1825                  */
1826                 if (extents_locked)
1827                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1828                                              lockstart, lockend, &cached_state);
1829                 else
1830                         free_extent_state(cached_state);
1831
1832                 btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
1833                 if (ret) {
1834                         btrfs_drop_pages(pages, num_pages);
1835                         break;
1836                 }
1837
1838                 release_bytes = 0;
1839                 if (only_release_metadata)
1840                         btrfs_check_nocow_unlock(BTRFS_I(inode));
1841
1842                 btrfs_drop_pages(pages, num_pages);
1843
1844                 cond_resched();
1845
1846                 balance_dirty_pages_ratelimited(inode->i_mapping);
1847
1848                 pos += copied;
1849                 num_written += copied;
1850         }
1851
1852         kfree(pages);
1853
1854         if (release_bytes) {
1855                 if (only_release_metadata) {
1856                         btrfs_check_nocow_unlock(BTRFS_I(inode));
1857                         btrfs_delalloc_release_metadata(BTRFS_I(inode),
1858                                         release_bytes, true);
1859                 } else {
1860                         btrfs_delalloc_release_space(BTRFS_I(inode),
1861                                         data_reserved,
1862                                         round_down(pos, fs_info->sectorsize),
1863                                         release_bytes, true);
1864                 }
1865         }
1866
1867         extent_changeset_free(data_reserved);
1868         if (num_written > 0) {
1869                 pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
1870                 iocb->ki_pos += num_written;
1871         }
1872 out:
1873         btrfs_inode_unlock(inode, ilock_flags);
1874         return num_written ? num_written : ret;
1875 }
1876
1877 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
1878                                const struct iov_iter *iter, loff_t offset)
1879 {
1880         const u32 blocksize_mask = fs_info->sectorsize - 1;
1881
1882         if (offset & blocksize_mask)
1883                 return -EINVAL;
1884
1885         if (iov_iter_alignment(iter) & blocksize_mask)
1886                 return -EINVAL;
1887
1888         return 0;
1889 }
1890
1891 static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
1892 {
1893         struct file *file = iocb->ki_filp;
1894         struct inode *inode = file_inode(file);
1895         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1896         loff_t pos;
1897         ssize_t written = 0;
1898         ssize_t written_buffered;
1899         loff_t endbyte;
1900         ssize_t err;
1901         unsigned int ilock_flags = 0;
1902         struct iomap_dio *dio = NULL;
1903
1904         if (iocb->ki_flags & IOCB_NOWAIT)
1905                 ilock_flags |= BTRFS_ILOCK_TRY;
1906
1907         /* If the write DIO is within EOF, use a shared lock */
1908         if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode))
1909                 ilock_flags |= BTRFS_ILOCK_SHARED;
1910
1911 relock:
1912         err = btrfs_inode_lock(inode, ilock_flags);
1913         if (err < 0)
1914                 return err;
1915
1916         err = generic_write_checks(iocb, from);
1917         if (err <= 0) {
1918                 btrfs_inode_unlock(inode, ilock_flags);
1919                 return err;
1920         }
1921
1922         err = btrfs_write_check(iocb, from, err);
1923         if (err < 0) {
1924                 btrfs_inode_unlock(inode, ilock_flags);
1925                 goto out;
1926         }
1927
1928         pos = iocb->ki_pos;
1929         /*
1930          * Re-check since file size may have changed just before taking the
1931          * lock or pos may have changed because of O_APPEND in generic_write_check()
1932          */
1933         if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
1934             pos + iov_iter_count(from) > i_size_read(inode)) {
1935                 btrfs_inode_unlock(inode, ilock_flags);
1936                 ilock_flags &= ~BTRFS_ILOCK_SHARED;
1937                 goto relock;
1938         }
1939
1940         if (check_direct_IO(fs_info, from, pos)) {
1941                 btrfs_inode_unlock(inode, ilock_flags);
1942                 goto buffered;
1943         }
1944
1945         dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
1946                              0);
1947
1948         btrfs_inode_unlock(inode, ilock_flags);
1949
1950         if (IS_ERR_OR_NULL(dio)) {
1951                 err = PTR_ERR_OR_ZERO(dio);
1952                 if (err < 0 && err != -ENOTBLK)
1953                         goto out;
1954         } else {
1955                 written = iomap_dio_complete(dio);
1956         }
1957
1958         if (written < 0 || !iov_iter_count(from)) {
1959                 err = written;
1960                 goto out;
1961         }
1962
1963 buffered:
1964         pos = iocb->ki_pos;
1965         written_buffered = btrfs_buffered_write(iocb, from);
1966         if (written_buffered < 0) {
1967                 err = written_buffered;
1968                 goto out;
1969         }
1970         /*
1971          * Ensure all data is persisted. We want the next direct IO read to be
1972          * able to read what was just written.
1973          */
1974         endbyte = pos + written_buffered - 1;
1975         err = btrfs_fdatawrite_range(inode, pos, endbyte);
1976         if (err)
1977                 goto out;
1978         err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
1979         if (err)
1980                 goto out;
1981         written += written_buffered;
1982         iocb->ki_pos = pos + written_buffered;
1983         invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
1984                                  endbyte >> PAGE_SHIFT);
1985 out:
1986         return written ? written : err;
1987 }
1988
1989 static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
1990                                     struct iov_iter *from)
1991 {
1992         struct file *file = iocb->ki_filp;
1993         struct btrfs_inode *inode = BTRFS_I(file_inode(file));
1994         ssize_t num_written = 0;
1995         const bool sync = iocb->ki_flags & IOCB_DSYNC;
1996
1997         /*
1998          * If the fs flips readonly due to some impossible error, although we
1999          * have opened a file as writable, we have to stop this write operation
2000          * to ensure consistency.
2001          */
2002         if (test_bit(BTRFS_FS_STATE_ERROR, &inode->root->fs_info->fs_state))
2003                 return -EROFS;
2004
2005         if (!(iocb->ki_flags & IOCB_DIRECT) &&
2006             (iocb->ki_flags & IOCB_NOWAIT))
2007                 return -EOPNOTSUPP;
2008
2009         if (sync)
2010                 atomic_inc(&inode->sync_writers);
2011
2012         if (iocb->ki_flags & IOCB_DIRECT)
2013                 num_written = btrfs_direct_write(iocb, from);
2014         else
2015                 num_written = btrfs_buffered_write(iocb, from);
2016
2017         /*
2018          * We also have to set last_sub_trans to the current log transid,
2019          * otherwise subsequent syncs to a file that's been synced in this
2020          * transaction will appear to have already occurred.
2021          */
2022         spin_lock(&inode->lock);
2023         inode->last_sub_trans = inode->root->log_transid;
2024         spin_unlock(&inode->lock);
2025         if (num_written > 0)
2026                 num_written = generic_write_sync(iocb, num_written);
2027
2028         if (sync)
2029                 atomic_dec(&inode->sync_writers);
2030
2031         current->backing_dev_info = NULL;
2032         return num_written;
2033 }
2034
2035 int btrfs_release_file(struct inode *inode, struct file *filp)
2036 {
2037         struct btrfs_file_private *private = filp->private_data;
2038
2039         if (private && private->filldir_buf)
2040                 kfree(private->filldir_buf);
2041         kfree(private);
2042         filp->private_data = NULL;
2043
2044         /*
2045          * Set by setattr when we are about to truncate a file from a non-zero
2046          * size to a zero size.  This tries to flush down new bytes that may
2047          * have been written if the application were using truncate to replace
2048          * a file in place.
2049          */
2050         if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE,
2051                                &BTRFS_I(inode)->runtime_flags))
2052                         filemap_flush(inode->i_mapping);
2053         return 0;
2054 }
2055
2056 static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
2057 {
2058         int ret;
2059         struct blk_plug plug;
2060
2061         /*
2062          * This is only called in fsync, which would do synchronous writes, so
2063          * a plug can merge adjacent IOs as much as possible.  Esp. in case of
2064          * multiple disks using raid profile, a large IO can be split to
2065          * several segments of stripe length (currently 64K).
2066          */
2067         blk_start_plug(&plug);
2068         atomic_inc(&BTRFS_I(inode)->sync_writers);
2069         ret = btrfs_fdatawrite_range(inode, start, end);
2070         atomic_dec(&BTRFS_I(inode)->sync_writers);
2071         blk_finish_plug(&plug);
2072
2073         return ret;
2074 }
2075
2076 /*
2077  * fsync call for both files and directories.  This logs the inode into
2078  * the tree log instead of forcing full commits whenever possible.
2079  *
2080  * It needs to call filemap_fdatawait so that all ordered extent updates are
2081  * in the metadata btree are up to date for copying to the log.
2082  *
2083  * It drops the inode mutex before doing the tree log commit.  This is an
2084  * important optimization for directories because holding the mutex prevents
2085  * new operations on the dir while we write to disk.
2086  */
2087 int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
2088 {
2089         struct dentry *dentry = file_dentry(file);
2090         struct inode *inode = d_inode(dentry);
2091         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2092         struct btrfs_root *root = BTRFS_I(inode)->root;
2093         struct btrfs_trans_handle *trans;
2094         struct btrfs_log_ctx ctx;
2095         int ret = 0, err;
2096         u64 len;
2097         bool full_sync;
2098
2099         trace_btrfs_sync_file(file, datasync);
2100
2101         btrfs_init_log_ctx(&ctx, inode);
2102
2103         /*
2104          * Always set the range to a full range, otherwise we can get into
2105          * several problems, from missing file extent items to represent holes
2106          * when not using the NO_HOLES feature, to log tree corruption due to
2107          * races between hole detection during logging and completion of ordered
2108          * extents outside the range, to missing checksums due to ordered extents
2109          * for which we flushed only a subset of their pages.
2110          */
2111         start = 0;
2112         end = LLONG_MAX;
2113         len = (u64)LLONG_MAX + 1;
2114
2115         /*
2116          * We write the dirty pages in the range and wait until they complete
2117          * out of the ->i_mutex. If so, we can flush the dirty pages by
2118          * multi-task, and make the performance up.  See
2119          * btrfs_wait_ordered_range for an explanation of the ASYNC check.
2120          */
2121         ret = start_ordered_ops(inode, start, end);
2122         if (ret)
2123                 goto out;
2124
2125         inode_lock(inode);
2126
2127         atomic_inc(&root->log_batch);
2128
2129         /*
2130          * Always check for the full sync flag while holding the inode's lock,
2131          * to avoid races with other tasks. The flag must be either set all the
2132          * time during logging or always off all the time while logging.
2133          */
2134         full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2135                              &BTRFS_I(inode)->runtime_flags);
2136
2137         /*
2138          * Before we acquired the inode's lock, someone may have dirtied more
2139          * pages in the target range. We need to make sure that writeback for
2140          * any such pages does not start while we are logging the inode, because
2141          * if it does, any of the following might happen when we are not doing a
2142          * full inode sync:
2143          *
2144          * 1) We log an extent after its writeback finishes but before its
2145          *    checksums are added to the csum tree, leading to -EIO errors
2146          *    when attempting to read the extent after a log replay.
2147          *
2148          * 2) We can end up logging an extent before its writeback finishes.
2149          *    Therefore after the log replay we will have a file extent item
2150          *    pointing to an unwritten extent (and no data checksums as well).
2151          *
2152          * So trigger writeback for any eventual new dirty pages and then we
2153          * wait for all ordered extents to complete below.
2154          */
2155         ret = start_ordered_ops(inode, start, end);
2156         if (ret) {
2157                 inode_unlock(inode);
2158                 goto out;
2159         }
2160
2161         /*
2162          * We have to do this here to avoid the priority inversion of waiting on
2163          * IO of a lower priority task while holding a transaction open.
2164          *
2165          * For a full fsync we wait for the ordered extents to complete while
2166          * for a fast fsync we wait just for writeback to complete, and then
2167          * attach the ordered extents to the transaction so that a transaction
2168          * commit waits for their completion, to avoid data loss if we fsync,
2169          * the current transaction commits before the ordered extents complete
2170          * and a power failure happens right after that.
2171          *
2172          * For zoned filesystem, if a write IO uses a ZONE_APPEND command, the
2173          * logical address recorded in the ordered extent may change. We need
2174          * to wait for the IO to stabilize the logical address.
2175          */
2176         if (full_sync || btrfs_is_zoned(fs_info)) {
2177                 ret = btrfs_wait_ordered_range(inode, start, len);
2178         } else {
2179                 /*
2180                  * Get our ordered extents as soon as possible to avoid doing
2181                  * checksum lookups in the csum tree, and use instead the
2182                  * checksums attached to the ordered extents.
2183                  */
2184                 btrfs_get_ordered_extents_for_logging(BTRFS_I(inode),
2185                                                       &ctx.ordered_extents);
2186                 ret = filemap_fdatawait_range(inode->i_mapping, start, end);
2187         }
2188
2189         if (ret)
2190                 goto out_release_extents;
2191
2192         atomic_inc(&root->log_batch);
2193
2194         /*
2195          * If we are doing a fast fsync we can not bail out if the inode's
2196          * last_trans is <= then the last committed transaction, because we only
2197          * update the last_trans of the inode during ordered extent completion,
2198          * and for a fast fsync we don't wait for that, we only wait for the
2199          * writeback to complete.
2200          */
2201         smp_mb();
2202         if (btrfs_inode_in_log(BTRFS_I(inode), fs_info->generation) ||
2203             (BTRFS_I(inode)->last_trans <= fs_info->last_trans_committed &&
2204              (full_sync || list_empty(&ctx.ordered_extents)))) {
2205                 /*
2206                  * We've had everything committed since the last time we were
2207                  * modified so clear this flag in case it was set for whatever
2208                  * reason, it's no longer relevant.
2209                  */
2210                 clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2211                           &BTRFS_I(inode)->runtime_flags);
2212                 /*
2213                  * An ordered extent might have started before and completed
2214                  * already with io errors, in which case the inode was not
2215                  * updated and we end up here. So check the inode's mapping
2216                  * for any errors that might have happened since we last
2217                  * checked called fsync.
2218                  */
2219                 ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
2220                 goto out_release_extents;
2221         }
2222
2223         /*
2224          * We use start here because we will need to wait on the IO to complete
2225          * in btrfs_sync_log, which could require joining a transaction (for
2226          * example checking cross references in the nocow path).  If we use join
2227          * here we could get into a situation where we're waiting on IO to
2228          * happen that is blocked on a transaction trying to commit.  With start
2229          * we inc the extwriter counter, so we wait for all extwriters to exit
2230          * before we start blocking joiners.  This comment is to keep somebody
2231          * from thinking they are super smart and changing this to
2232          * btrfs_join_transaction *cough*Josef*cough*.
2233          */
2234         trans = btrfs_start_transaction(root, 0);
2235         if (IS_ERR(trans)) {
2236                 ret = PTR_ERR(trans);
2237                 goto out_release_extents;
2238         }
2239         trans->in_fsync = true;
2240
2241         ret = btrfs_log_dentry_safe(trans, dentry, &ctx);
2242         btrfs_release_log_ctx_extents(&ctx);
2243         if (ret < 0) {
2244                 /* Fallthrough and commit/free transaction. */
2245                 ret = 1;
2246         }
2247
2248         /* we've logged all the items and now have a consistent
2249          * version of the file in the log.  It is possible that
2250          * someone will come in and modify the file, but that's
2251          * fine because the log is consistent on disk, and we
2252          * have references to all of the file's extents
2253          *
2254          * It is possible that someone will come in and log the
2255          * file again, but that will end up using the synchronization
2256          * inside btrfs_sync_log to keep things safe.
2257          */
2258         inode_unlock(inode);
2259
2260         if (ret != BTRFS_NO_LOG_SYNC) {
2261                 if (!ret) {
2262                         ret = btrfs_sync_log(trans, root, &ctx);
2263                         if (!ret) {
2264                                 ret = btrfs_end_transaction(trans);
2265                                 goto out;
2266                         }
2267                 }
2268                 if (!full_sync) {
2269                         ret = btrfs_wait_ordered_range(inode, start, len);
2270                         if (ret) {
2271                                 btrfs_end_transaction(trans);
2272                                 goto out;
2273                         }
2274                 }
2275                 ret = btrfs_commit_transaction(trans);
2276         } else {
2277                 ret = btrfs_end_transaction(trans);
2278         }
2279 out:
2280         ASSERT(list_empty(&ctx.list));
2281         err = file_check_and_advance_wb_err(file);
2282         if (!ret)
2283                 ret = err;
2284         return ret > 0 ? -EIO : ret;
2285
2286 out_release_extents:
2287         btrfs_release_log_ctx_extents(&ctx);
2288         inode_unlock(inode);
2289         goto out;
2290 }
2291
2292 static const struct vm_operations_struct btrfs_file_vm_ops = {
2293         .fault          = filemap_fault,
2294         .map_pages      = filemap_map_pages,
2295         .page_mkwrite   = btrfs_page_mkwrite,
2296 };
2297
2298 static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
2299 {
2300         struct address_space *mapping = filp->f_mapping;
2301
2302         if (!mapping->a_ops->readpage)
2303                 return -ENOEXEC;
2304
2305         file_accessed(filp);
2306         vma->vm_ops = &btrfs_file_vm_ops;
2307
2308         return 0;
2309 }
2310
2311 static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
2312                           int slot, u64 start, u64 end)
2313 {
2314         struct btrfs_file_extent_item *fi;
2315         struct btrfs_key key;
2316
2317         if (slot < 0 || slot >= btrfs_header_nritems(leaf))
2318                 return 0;
2319
2320         btrfs_item_key_to_cpu(leaf, &key, slot);
2321         if (key.objectid != btrfs_ino(inode) ||
2322             key.type != BTRFS_EXTENT_DATA_KEY)
2323                 return 0;
2324
2325         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2326
2327         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2328                 return 0;
2329
2330         if (btrfs_file_extent_disk_bytenr(leaf, fi))
2331                 return 0;
2332
2333         if (key.offset == end)
2334                 return 1;
2335         if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
2336                 return 1;
2337         return 0;
2338 }
2339
2340 static int fill_holes(struct btrfs_trans_handle *trans,
2341                 struct btrfs_inode *inode,
2342                 struct btrfs_path *path, u64 offset, u64 end)
2343 {
2344         struct btrfs_fs_info *fs_info = trans->fs_info;
2345         struct btrfs_root *root = inode->root;
2346         struct extent_buffer *leaf;
2347         struct btrfs_file_extent_item *fi;
2348         struct extent_map *hole_em;
2349         struct extent_map_tree *em_tree = &inode->extent_tree;
2350         struct btrfs_key key;
2351         int ret;
2352
2353         if (btrfs_fs_incompat(fs_info, NO_HOLES))
2354                 goto out;
2355
2356         key.objectid = btrfs_ino(inode);
2357         key.type = BTRFS_EXTENT_DATA_KEY;
2358         key.offset = offset;
2359
2360         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2361         if (ret <= 0) {
2362                 /*
2363                  * We should have dropped this offset, so if we find it then
2364                  * something has gone horribly wrong.
2365                  */
2366                 if (ret == 0)
2367                         ret = -EINVAL;
2368                 return ret;
2369         }
2370
2371         leaf = path->nodes[0];
2372         if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
2373                 u64 num_bytes;
2374
2375                 path->slots[0]--;
2376                 fi = btrfs_item_ptr(leaf, path->slots[0],
2377                                     struct btrfs_file_extent_item);
2378                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
2379                         end - offset;
2380                 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2381                 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2382                 btrfs_set_file_extent_offset(leaf, fi, 0);
2383                 btrfs_mark_buffer_dirty(leaf);
2384                 goto out;
2385         }
2386
2387         if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
2388                 u64 num_bytes;
2389
2390                 key.offset = offset;
2391                 btrfs_set_item_key_safe(fs_info, path, &key);
2392                 fi = btrfs_item_ptr(leaf, path->slots[0],
2393                                     struct btrfs_file_extent_item);
2394                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
2395                         offset;
2396                 btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2397                 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
2398                 btrfs_set_file_extent_offset(leaf, fi, 0);
2399                 btrfs_mark_buffer_dirty(leaf);
2400                 goto out;
2401         }
2402         btrfs_release_path(path);
2403
2404         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode),
2405                         offset, 0, 0, end - offset, 0, end - offset, 0, 0, 0);
2406         if (ret)
2407                 return ret;
2408
2409 out:
2410         btrfs_release_path(path);
2411
2412         hole_em = alloc_extent_map();
2413         if (!hole_em) {
2414                 btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2415                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
2416         } else {
2417                 hole_em->start = offset;
2418                 hole_em->len = end - offset;
2419                 hole_em->ram_bytes = hole_em->len;
2420                 hole_em->orig_start = offset;
2421
2422                 hole_em->block_start = EXTENT_MAP_HOLE;
2423                 hole_em->block_len = 0;
2424                 hole_em->orig_block_len = 0;
2425                 hole_em->compress_type = BTRFS_COMPRESS_NONE;
2426                 hole_em->generation = trans->transid;
2427
2428                 do {
2429                         btrfs_drop_extent_cache(inode, offset, end - 1, 0);
2430                         write_lock(&em_tree->lock);
2431                         ret = add_extent_mapping(em_tree, hole_em, 1);
2432                         write_unlock(&em_tree->lock);
2433                 } while (ret == -EEXIST);
2434                 free_extent_map(hole_em);
2435                 if (ret)
2436                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2437                                         &inode->runtime_flags);
2438         }
2439
2440         return 0;
2441 }
2442
2443 /*
2444  * Find a hole extent on given inode and change start/len to the end of hole
2445  * extent.(hole/vacuum extent whose em->start <= start &&
2446  *         em->start + em->len > start)
2447  * When a hole extent is found, return 1 and modify start/len.
2448  */
2449 static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len)
2450 {
2451         struct btrfs_fs_info *fs_info = inode->root->fs_info;
2452         struct extent_map *em;
2453         int ret = 0;
2454
2455         em = btrfs_get_extent(inode, NULL, 0,
2456                               round_down(*start, fs_info->sectorsize),
2457                               round_up(*len, fs_info->sectorsize));
2458         if (IS_ERR(em))
2459                 return PTR_ERR(em);
2460
2461         /* Hole or vacuum extent(only exists in no-hole mode) */
2462         if (em->block_start == EXTENT_MAP_HOLE) {
2463                 ret = 1;
2464                 *len = em->start + em->len > *start + *len ?
2465                        0 : *start + *len - em->start - em->len;
2466                 *start = em->start + em->len;
2467         }
2468         free_extent_map(em);
2469         return ret;
2470 }
2471
2472 static int btrfs_punch_hole_lock_range(struct inode *inode,
2473                                        const u64 lockstart,
2474                                        const u64 lockend,
2475                                        struct extent_state **cached_state)
2476 {
2477         while (1) {
2478                 struct btrfs_ordered_extent *ordered;
2479                 int ret;
2480
2481                 truncate_pagecache_range(inode, lockstart, lockend);
2482
2483                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2484                                  cached_state);
2485                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
2486                                                             lockend);
2487
2488                 /*
2489                  * We need to make sure we have no ordered extents in this range
2490                  * and nobody raced in and read a page in this range, if we did
2491                  * we need to try again.
2492                  */
2493                 if ((!ordered ||
2494                     (ordered->file_offset + ordered->num_bytes <= lockstart ||
2495                      ordered->file_offset > lockend)) &&
2496                      !filemap_range_has_page(inode->i_mapping,
2497                                              lockstart, lockend)) {
2498                         if (ordered)
2499                                 btrfs_put_ordered_extent(ordered);
2500                         break;
2501                 }
2502                 if (ordered)
2503                         btrfs_put_ordered_extent(ordered);
2504                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
2505                                      lockend, cached_state);
2506                 ret = btrfs_wait_ordered_range(inode, lockstart,
2507                                                lockend - lockstart + 1);
2508                 if (ret)
2509                         return ret;
2510         }
2511         return 0;
2512 }
2513
2514 static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
2515                                      struct btrfs_inode *inode,
2516                                      struct btrfs_path *path,
2517                                      struct btrfs_replace_extent_info *extent_info,
2518                                      const u64 replace_len,
2519                                      const u64 bytes_to_drop)
2520 {
2521         struct btrfs_fs_info *fs_info = trans->fs_info;
2522         struct btrfs_root *root = inode->root;
2523         struct btrfs_file_extent_item *extent;
2524         struct extent_buffer *leaf;
2525         struct btrfs_key key;
2526         int slot;
2527         struct btrfs_ref ref = { 0 };
2528         int ret;
2529
2530         if (replace_len == 0)
2531                 return 0;
2532
2533         if (extent_info->disk_offset == 0 &&
2534             btrfs_fs_incompat(fs_info, NO_HOLES)) {
2535                 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2536                 return 0;
2537         }
2538
2539         key.objectid = btrfs_ino(inode);
2540         key.type = BTRFS_EXTENT_DATA_KEY;
2541         key.offset = extent_info->file_offset;
2542         ret = btrfs_insert_empty_item(trans, root, path, &key,
2543                                       sizeof(struct btrfs_file_extent_item));
2544         if (ret)
2545                 return ret;
2546         leaf = path->nodes[0];
2547         slot = path->slots[0];
2548         write_extent_buffer(leaf, extent_info->extent_buf,
2549                             btrfs_item_ptr_offset(leaf, slot),
2550                             sizeof(struct btrfs_file_extent_item));
2551         extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
2552         ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
2553         btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
2554         btrfs_set_file_extent_num_bytes(leaf, extent, replace_len);
2555         if (extent_info->is_new_extent)
2556                 btrfs_set_file_extent_generation(leaf, extent, trans->transid);
2557         btrfs_mark_buffer_dirty(leaf);
2558         btrfs_release_path(path);
2559
2560         ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset,
2561                                                 replace_len);
2562         if (ret)
2563                 return ret;
2564
2565         /* If it's a hole, nothing more needs to be done. */
2566         if (extent_info->disk_offset == 0) {
2567                 btrfs_update_inode_bytes(inode, 0, bytes_to_drop);
2568                 return 0;
2569         }
2570
2571         btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop);
2572
2573         if (extent_info->is_new_extent && extent_info->insertions == 0) {
2574                 key.objectid = extent_info->disk_offset;
2575                 key.type = BTRFS_EXTENT_ITEM_KEY;
2576                 key.offset = extent_info->disk_len;
2577                 ret = btrfs_alloc_reserved_file_extent(trans, root,
2578                                                        btrfs_ino(inode),
2579                                                        extent_info->file_offset,
2580                                                        extent_info->qgroup_reserved,
2581                                                        &key);
2582         } else {
2583                 u64 ref_offset;
2584
2585                 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2586                                        extent_info->disk_offset,
2587                                        extent_info->disk_len, 0);
2588                 ref_offset = extent_info->file_offset - extent_info->data_offset;
2589                 btrfs_init_data_ref(&ref, root->root_key.objectid,
2590                                     btrfs_ino(inode), ref_offset);
2591                 ret = btrfs_inc_extent_ref(trans, &ref);
2592         }
2593
2594         extent_info->insertions++;
2595
2596         return ret;
2597 }
2598
2599 /*
2600  * The respective range must have been previously locked, as well as the inode.
2601  * The end offset is inclusive (last byte of the range).
2602  * @extent_info is NULL for fallocate's hole punching and non-NULL when replacing
2603  * the file range with an extent.
2604  * When not punching a hole, we don't want to end up in a state where we dropped
2605  * extents without inserting a new one, so we must abort the transaction to avoid
2606  * a corruption.
2607  */
2608 int btrfs_replace_file_extents(struct inode *inode, struct btrfs_path *path,
2609                            const u64 start, const u64 end,
2610                            struct btrfs_replace_extent_info *extent_info,
2611                            struct btrfs_trans_handle **trans_out)
2612 {
2613         struct btrfs_drop_extents_args drop_args = { 0 };
2614         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2615         u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1);
2616         u64 ino_size = round_up(inode->i_size, fs_info->sectorsize);
2617         struct btrfs_root *root = BTRFS_I(inode)->root;
2618         struct btrfs_trans_handle *trans = NULL;
2619         struct btrfs_block_rsv *rsv;
2620         unsigned int rsv_count;
2621         u64 cur_offset;
2622         u64 len = end - start;
2623         int ret = 0;
2624
2625         if (end <= start)
2626                 return -EINVAL;
2627
2628         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
2629         if (!rsv) {
2630                 ret = -ENOMEM;
2631                 goto out;
2632         }
2633         rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1);
2634         rsv->failfast = 1;
2635
2636         /*
2637          * 1 - update the inode
2638          * 1 - removing the extents in the range
2639          * 1 - adding the hole extent if no_holes isn't set or if we are
2640          *     replacing the range with a new extent
2641          */
2642         if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info)
2643                 rsv_count = 3;
2644         else
2645                 rsv_count = 2;
2646
2647         trans = btrfs_start_transaction(root, rsv_count);
2648         if (IS_ERR(trans)) {
2649                 ret = PTR_ERR(trans);
2650                 trans = NULL;
2651                 goto out_free;
2652         }
2653
2654         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
2655                                       min_size, false);
2656         BUG_ON(ret);
2657         trans->block_rsv = rsv;
2658
2659         cur_offset = start;
2660         drop_args.path = path;
2661         drop_args.end = end + 1;
2662         drop_args.drop_cache = true;
2663         while (cur_offset < end) {
2664                 drop_args.start = cur_offset;
2665                 ret = btrfs_drop_extents(trans, root, BTRFS_I(inode), &drop_args);
2666                 /* If we are punching a hole decrement the inode's byte count */
2667                 if (!extent_info)
2668                         btrfs_update_inode_bytes(BTRFS_I(inode), 0,
2669                                                  drop_args.bytes_found);
2670                 if (ret != -ENOSPC) {
2671                         /*
2672                          * When cloning we want to avoid transaction aborts when
2673                          * nothing was done and we are attempting to clone parts
2674                          * of inline extents, in such cases -EOPNOTSUPP is
2675                          * returned by __btrfs_drop_extents() without having
2676                          * changed anything in the file.
2677                          */
2678                         if (extent_info && !extent_info->is_new_extent &&
2679                             ret && ret != -EOPNOTSUPP)
2680                                 btrfs_abort_transaction(trans, ret);
2681                         break;
2682                 }
2683
2684                 trans->block_rsv = &fs_info->trans_block_rsv;
2685
2686                 if (!extent_info && cur_offset < drop_args.drop_end &&
2687                     cur_offset < ino_size) {
2688                         ret = fill_holes(trans, BTRFS_I(inode), path,
2689                                          cur_offset, drop_args.drop_end);
2690                         if (ret) {
2691                                 /*
2692                                  * If we failed then we didn't insert our hole
2693                                  * entries for the area we dropped, so now the
2694                                  * fs is corrupted, so we must abort the
2695                                  * transaction.
2696                                  */
2697                                 btrfs_abort_transaction(trans, ret);
2698                                 break;
2699                         }
2700                 } else if (!extent_info && cur_offset < drop_args.drop_end) {
2701                         /*
2702                          * We are past the i_size here, but since we didn't
2703                          * insert holes we need to clear the mapped area so we
2704                          * know to not set disk_i_size in this area until a new
2705                          * file extent is inserted here.
2706                          */
2707                         ret = btrfs_inode_clear_file_extent_range(BTRFS_I(inode),
2708                                         cur_offset,
2709                                         drop_args.drop_end - cur_offset);
2710                         if (ret) {
2711                                 /*
2712                                  * We couldn't clear our area, so we could
2713                                  * presumably adjust up and corrupt the fs, so
2714                                  * we need to abort.
2715                                  */
2716                                 btrfs_abort_transaction(trans, ret);
2717                                 break;
2718                         }
2719                 }
2720
2721                 if (extent_info &&
2722                     drop_args.drop_end > extent_info->file_offset) {
2723                         u64 replace_len = drop_args.drop_end -
2724                                           extent_info->file_offset;
2725
2726                         ret = btrfs_insert_replace_extent(trans, BTRFS_I(inode),
2727                                         path, extent_info, replace_len,
2728                                         drop_args.bytes_found);
2729                         if (ret) {
2730                                 btrfs_abort_transaction(trans, ret);
2731                                 break;
2732                         }
2733                         extent_info->data_len -= replace_len;
2734                         extent_info->data_offset += replace_len;
2735                         extent_info->file_offset += replace_len;
2736                 }
2737
2738                 cur_offset = drop_args.drop_end;
2739
2740                 ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2741                 if (ret)
2742                         break;
2743
2744                 btrfs_end_transaction(trans);
2745                 btrfs_btree_balance_dirty(fs_info);
2746
2747                 trans = btrfs_start_transaction(root, rsv_count);
2748                 if (IS_ERR(trans)) {
2749                         ret = PTR_ERR(trans);
2750                         trans = NULL;
2751                         break;
2752                 }
2753
2754                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
2755                                               rsv, min_size, false);
2756                 BUG_ON(ret);    /* shouldn't happen */
2757                 trans->block_rsv = rsv;
2758
2759                 if (!extent_info) {
2760                         ret = find_first_non_hole(BTRFS_I(inode), &cur_offset,
2761                                                   &len);
2762                         if (unlikely(ret < 0))
2763                                 break;
2764                         if (ret && !len) {
2765                                 ret = 0;
2766                                 break;
2767                         }
2768                 }
2769         }
2770
2771         /*
2772          * If we were cloning, force the next fsync to be a full one since we
2773          * we replaced (or just dropped in the case of cloning holes when
2774          * NO_HOLES is enabled) extents and extent maps.
2775          * This is for the sake of simplicity, and cloning into files larger
2776          * than 16Mb would force the full fsync any way (when
2777          * try_release_extent_mapping() is invoked during page cache truncation.
2778          */
2779         if (extent_info && !extent_info->is_new_extent)
2780                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
2781                         &BTRFS_I(inode)->runtime_flags);
2782
2783         if (ret)
2784                 goto out_trans;
2785
2786         trans->block_rsv = &fs_info->trans_block_rsv;
2787         /*
2788          * If we are using the NO_HOLES feature we might have had already an
2789          * hole that overlaps a part of the region [lockstart, lockend] and
2790          * ends at (or beyond) lockend. Since we have no file extent items to
2791          * represent holes, drop_end can be less than lockend and so we must
2792          * make sure we have an extent map representing the existing hole (the
2793          * call to __btrfs_drop_extents() might have dropped the existing extent
2794          * map representing the existing hole), otherwise the fast fsync path
2795          * will not record the existence of the hole region
2796          * [existing_hole_start, lockend].
2797          */
2798         if (drop_args.drop_end <= end)
2799                 drop_args.drop_end = end + 1;
2800         /*
2801          * Don't insert file hole extent item if it's for a range beyond eof
2802          * (because it's useless) or if it represents a 0 bytes range (when
2803          * cur_offset == drop_end).
2804          */
2805         if (!extent_info && cur_offset < ino_size &&
2806             cur_offset < drop_args.drop_end) {
2807                 ret = fill_holes(trans, BTRFS_I(inode), path,
2808                                  cur_offset, drop_args.drop_end);
2809                 if (ret) {
2810                         /* Same comment as above. */
2811                         btrfs_abort_transaction(trans, ret);
2812                         goto out_trans;
2813                 }
2814         } else if (!extent_info && cur_offset < drop_args.drop_end) {
2815                 /* See the comment in the loop above for the reasoning here. */
2816                 ret = btrfs_inode_clear_file_extent_range(BTRFS_I(inode),
2817                                 cur_offset, drop_args.drop_end - cur_offset);
2818                 if (ret) {
2819                         btrfs_abort_transaction(trans, ret);
2820                         goto out_trans;
2821                 }
2822
2823         }
2824         if (extent_info) {
2825                 ret = btrfs_insert_replace_extent(trans, BTRFS_I(inode), path,
2826                                 extent_info, extent_info->data_len,
2827                                 drop_args.bytes_found);
2828                 if (ret) {
2829                         btrfs_abort_transaction(trans, ret);
2830                         goto out_trans;
2831                 }
2832         }
2833
2834 out_trans:
2835         if (!trans)
2836                 goto out_free;
2837
2838         trans->block_rsv = &fs_info->trans_block_rsv;
2839         if (ret)
2840                 btrfs_end_transaction(trans);
2841         else
2842                 *trans_out = trans;
2843 out_free:
2844         btrfs_free_block_rsv(fs_info, rsv);
2845 out:
2846         return ret;
2847 }
2848
2849 static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
2850 {
2851         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2852         struct btrfs_root *root = BTRFS_I(inode)->root;
2853         struct extent_state *cached_state = NULL;
2854         struct btrfs_path *path;
2855         struct btrfs_trans_handle *trans = NULL;
2856         u64 lockstart;
2857         u64 lockend;
2858         u64 tail_start;
2859         u64 tail_len;
2860         u64 orig_start = offset;
2861         int ret = 0;
2862         bool same_block;
2863         u64 ino_size;
2864         bool truncated_block = false;
2865         bool updated_inode = false;
2866
2867         ret = btrfs_wait_ordered_range(inode, offset, len);
2868         if (ret)
2869                 return ret;
2870
2871         inode_lock(inode);
2872         ino_size = round_up(inode->i_size, fs_info->sectorsize);
2873         ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2874         if (ret < 0)
2875                 goto out_only_mutex;
2876         if (ret && !len) {
2877                 /* Already in a large hole */
2878                 ret = 0;
2879                 goto out_only_mutex;
2880         }
2881
2882         lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode)));
2883         lockend = round_down(offset + len,
2884                              btrfs_inode_sectorsize(BTRFS_I(inode))) - 1;
2885         same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
2886                 == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
2887         /*
2888          * We needn't truncate any block which is beyond the end of the file
2889          * because we are sure there is no data there.
2890          */
2891         /*
2892          * Only do this if we are in the same block and we aren't doing the
2893          * entire block.
2894          */
2895         if (same_block && len < fs_info->sectorsize) {
2896                 if (offset < ino_size) {
2897                         truncated_block = true;
2898                         ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
2899                                                    0);
2900                 } else {
2901                         ret = 0;
2902                 }
2903                 goto out_only_mutex;
2904         }
2905
2906         /* zero back part of the first block */
2907         if (offset < ino_size) {
2908                 truncated_block = true;
2909                 ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
2910                 if (ret) {
2911                         inode_unlock(inode);
2912                         return ret;
2913                 }
2914         }
2915
2916         /* Check the aligned pages after the first unaligned page,
2917          * if offset != orig_start, which means the first unaligned page
2918          * including several following pages are already in holes,
2919          * the extra check can be skipped */
2920         if (offset == orig_start) {
2921                 /* after truncate page, check hole again */
2922                 len = offset + len - lockstart;
2923                 offset = lockstart;
2924                 ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
2925                 if (ret < 0)
2926                         goto out_only_mutex;
2927                 if (ret && !len) {
2928                         ret = 0;
2929                         goto out_only_mutex;
2930                 }
2931                 lockstart = offset;
2932         }
2933
2934         /* Check the tail unaligned part is in a hole */
2935         tail_start = lockend + 1;
2936         tail_len = offset + len - tail_start;
2937         if (tail_len) {
2938                 ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len);
2939                 if (unlikely(ret < 0))
2940                         goto out_only_mutex;
2941                 if (!ret) {
2942                         /* zero the front end of the last page */
2943                         if (tail_start + tail_len < ino_size) {
2944                                 truncated_block = true;
2945                                 ret = btrfs_truncate_block(BTRFS_I(inode),
2946                                                         tail_start + tail_len,
2947                                                         0, 1);
2948                                 if (ret)
2949                                         goto out_only_mutex;
2950                         }
2951                 }
2952         }
2953
2954         if (lockend < lockstart) {
2955                 ret = 0;
2956                 goto out_only_mutex;
2957         }
2958
2959         ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
2960                                           &cached_state);
2961         if (ret)
2962                 goto out_only_mutex;
2963
2964         path = btrfs_alloc_path();
2965         if (!path) {
2966                 ret = -ENOMEM;
2967                 goto out;
2968         }
2969
2970         ret = btrfs_replace_file_extents(inode, path, lockstart, lockend, NULL,
2971                                      &trans);
2972         btrfs_free_path(path);
2973         if (ret)
2974                 goto out;
2975
2976         ASSERT(trans != NULL);
2977         inode_inc_iversion(inode);
2978         inode->i_mtime = inode->i_ctime = current_time(inode);
2979         ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2980         updated_inode = true;
2981         btrfs_end_transaction(trans);
2982         btrfs_btree_balance_dirty(fs_info);
2983 out:
2984         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
2985                              &cached_state);
2986 out_only_mutex:
2987         if (!updated_inode && truncated_block && !ret) {
2988                 /*
2989                  * If we only end up zeroing part of a page, we still need to
2990                  * update the inode item, so that all the time fields are
2991                  * updated as well as the necessary btrfs inode in memory fields
2992                  * for detecting, at fsync time, if the inode isn't yet in the
2993                  * log tree or it's there but not up to date.
2994                  */
2995                 struct timespec64 now = current_time(inode);
2996
2997                 inode_inc_iversion(inode);
2998                 inode->i_mtime = now;
2999                 inode->i_ctime = now;
3000                 trans = btrfs_start_transaction(root, 1);
3001                 if (IS_ERR(trans)) {
3002                         ret = PTR_ERR(trans);
3003                 } else {
3004                         int ret2;
3005
3006                         ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
3007                         ret2 = btrfs_end_transaction(trans);
3008                         if (!ret)
3009                                 ret = ret2;
3010                 }
3011         }
3012         inode_unlock(inode);
3013         return ret;
3014 }
3015
3016 /* Helper structure to record which range is already reserved */
3017 struct falloc_range {
3018         struct list_head list;
3019         u64 start;
3020         u64 len;
3021 };
3022
3023 /*
3024  * Helper function to add falloc range
3025  *
3026  * Caller should have locked the larger range of extent containing
3027  * [start, len)
3028  */
3029 static int add_falloc_range(struct list_head *head, u64 start, u64 len)
3030 {
3031         struct falloc_range *prev = NULL;
3032         struct falloc_range *range = NULL;
3033
3034         if (list_empty(head))
3035                 goto insert;
3036
3037         /*
3038          * As fallocate iterate by bytenr order, we only need to check
3039          * the last range.
3040          */
3041         prev = list_entry(head->prev, struct falloc_range, list);
3042         if (prev->start + prev->len == start) {
3043                 prev->len += len;
3044                 return 0;
3045         }
3046 insert:
3047         range = kmalloc(sizeof(*range), GFP_KERNEL);
3048         if (!range)
3049                 return -ENOMEM;
3050         range->start = start;
3051         range->len = len;
3052         list_add_tail(&range->list, head);
3053         return 0;
3054 }
3055
3056 static int btrfs_fallocate_update_isize(struct inode *inode,
3057                                         const u64 end,
3058                                         const int mode)
3059 {
3060         struct btrfs_trans_handle *trans;
3061         struct btrfs_root *root = BTRFS_I(inode)->root;
3062         int ret;
3063         int ret2;
3064
3065         if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
3066                 return 0;
3067
3068         trans = btrfs_start_transaction(root, 1);
3069         if (IS_ERR(trans))
3070                 return PTR_ERR(trans);
3071
3072         inode->i_ctime = current_time(inode);
3073         i_size_write(inode, end);
3074         btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0);
3075         ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
3076         ret2 = btrfs_end_transaction(trans);
3077
3078         return ret ? ret : ret2;
3079 }
3080
3081 enum {
3082         RANGE_BOUNDARY_WRITTEN_EXTENT,
3083         RANGE_BOUNDARY_PREALLOC_EXTENT,
3084         RANGE_BOUNDARY_HOLE,
3085 };
3086
3087 static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode,
3088                                                  u64 offset)
3089 {
3090         const u64 sectorsize = btrfs_inode_sectorsize(inode);
3091         struct extent_map *em;
3092         int ret;
3093
3094         offset = round_down(offset, sectorsize);
3095         em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize);
3096         if (IS_ERR(em))
3097                 return PTR_ERR(em);
3098
3099         if (em->block_start == EXTENT_MAP_HOLE)
3100                 ret = RANGE_BOUNDARY_HOLE;
3101         else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
3102                 ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
3103         else
3104                 ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
3105
3106         free_extent_map(em);
3107         return ret;
3108 }
3109
3110 static int btrfs_zero_range(struct inode *inode,
3111                             loff_t offset,
3112                             loff_t len,
3113                             const int mode)
3114 {
3115         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
3116         struct extent_map *em;
3117         struct extent_changeset *data_reserved = NULL;
3118         int ret;
3119         u64 alloc_hint = 0;
3120         const u64 sectorsize = btrfs_inode_sectorsize(BTRFS_I(inode));
3121         u64 alloc_start = round_down(offset, sectorsize);
3122         u64 alloc_end = round_up(offset + len, sectorsize);
3123         u64 bytes_to_reserve = 0;
3124         bool space_reserved = false;
3125
3126         inode_dio_wait(inode);
3127
3128         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
3129                               alloc_end - alloc_start);
3130         if (IS_ERR(em)) {
3131                 ret = PTR_ERR(em);
3132                 goto out;
3133         }
3134
3135         /*
3136          * Avoid hole punching and extent allocation for some cases. More cases
3137          * could be considered, but these are unlikely common and we keep things
3138          * as simple as possible for now. Also, intentionally, if the target
3139          * range contains one or more prealloc extents together with regular
3140          * extents and holes, we drop all the existing extents and allocate a
3141          * new prealloc extent, so that we get a larger contiguous disk extent.
3142          */
3143         if (em->start <= alloc_start &&
3144             test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3145                 const u64 em_end = em->start + em->len;
3146
3147                 if (em_end >= offset + len) {
3148                         /*
3149                          * The whole range is already a prealloc extent,
3150                          * do nothing except updating the inode's i_size if
3151                          * needed.
3152                          */
3153                         free_extent_map(em);
3154                         ret = btrfs_fallocate_update_isize(inode, offset + len,
3155                                                            mode);
3156                         goto out;
3157                 }
3158                 /*
3159                  * Part of the range is already a prealloc extent, so operate
3160                  * only on the remaining part of the range.
3161                  */
3162                 alloc_start = em_end;
3163                 ASSERT(IS_ALIGNED(alloc_start, sectorsize));
3164                 len = offset + len - alloc_start;
3165                 offset = alloc_start;
3166                 alloc_hint = em->block_start + em->len;
3167         }
3168         free_extent_map(em);
3169
3170         if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
3171             BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
3172                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start,
3173                                       sectorsize);
3174                 if (IS_ERR(em)) {
3175                         ret = PTR_ERR(em);
3176                         goto out;
3177                 }
3178
3179                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3180                         free_extent_map(em);
3181                         ret = btrfs_fallocate_update_isize(inode, offset + len,
3182                                                            mode);
3183                         goto out;
3184                 }
3185                 if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
3186                         free_extent_map(em);
3187                         ret = btrfs_truncate_block(BTRFS_I(inode), offset, len,
3188                                                    0);
3189                         if (!ret)
3190                                 ret = btrfs_fallocate_update_isize(inode,
3191                                                                    offset + len,
3192                                                                    mode);
3193                         return ret;
3194                 }
3195                 free_extent_map(em);
3196                 alloc_start = round_down(offset, sectorsize);
3197                 alloc_end = alloc_start + sectorsize;
3198                 goto reserve_space;
3199         }
3200
3201         alloc_start = round_up(offset, sectorsize);
3202         alloc_end = round_down(offset + len, sectorsize);
3203
3204         /*
3205          * For unaligned ranges, check the pages at the boundaries, they might
3206          * map to an extent, in which case we need to partially zero them, or
3207          * they might map to a hole, in which case we need our allocation range
3208          * to cover them.
3209          */
3210         if (!IS_ALIGNED(offset, sectorsize)) {
3211                 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
3212                                                             offset);
3213                 if (ret < 0)
3214                         goto out;
3215                 if (ret == RANGE_BOUNDARY_HOLE) {
3216                         alloc_start = round_down(offset, sectorsize);
3217                         ret = 0;
3218                 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
3219                         ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0);
3220                         if (ret)
3221                                 goto out;
3222                 } else {
3223                         ret = 0;
3224                 }
3225         }
3226
3227         if (!IS_ALIGNED(offset + len, sectorsize)) {
3228                 ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode),
3229                                                             offset + len);
3230                 if (ret < 0)
3231                         goto out;
3232                 if (ret == RANGE_BOUNDARY_HOLE) {
3233                         alloc_end = round_up(offset + len, sectorsize);
3234                         ret = 0;
3235                 } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
3236                         ret = btrfs_truncate_block(BTRFS_I(inode), offset + len,
3237                                                    0, 1);
3238                         if (ret)
3239                                 goto out;
3240                 } else {
3241                         ret = 0;
3242                 }
3243         }
3244
3245 reserve_space:
3246         if (alloc_start < alloc_end) {
3247                 struct extent_state *cached_state = NULL;
3248                 const u64 lockstart = alloc_start;
3249                 const u64 lockend = alloc_end - 1;
3250
3251                 bytes_to_reserve = alloc_end - alloc_start;
3252                 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3253                                                       bytes_to_reserve);
3254                 if (ret < 0)
3255                         goto out;
3256                 space_reserved = true;
3257                 ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
3258                                                   &cached_state);
3259                 if (ret)
3260                         goto out;
3261                 ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved,
3262                                                 alloc_start, bytes_to_reserve);
3263                 if (ret)
3264                         goto out;
3265                 ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
3266                                                 alloc_end - alloc_start,
3267                                                 i_blocksize(inode),
3268                                                 offset + len, &alloc_hint);
3269                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
3270                                      lockend, &cached_state);
3271                 /* btrfs_prealloc_file_range releases reserved space on error */
3272                 if (ret) {
3273                         space_reserved = false;
3274                         goto out;
3275                 }
3276         }
3277         ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
3278  out:
3279         if (ret && space_reserved)
3280                 btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3281                                                alloc_start, bytes_to_reserve);
3282         extent_changeset_free(data_reserved);
3283
3284         return ret;
3285 }
3286
3287 static long btrfs_fallocate(struct file *file, int mode,
3288                             loff_t offset, loff_t len)
3289 {
3290         struct inode *inode = file_inode(file);
3291         struct extent_state *cached_state = NULL;
3292         struct extent_changeset *data_reserved = NULL;
3293         struct falloc_range *range;
3294         struct falloc_range *tmp;
3295         struct list_head reserve_list;
3296         u64 cur_offset;
3297         u64 last_byte;
3298         u64 alloc_start;
3299         u64 alloc_end;
3300         u64 alloc_hint = 0;
3301         u64 locked_end;
3302         u64 actual_end = 0;
3303         struct extent_map *em;
3304         int blocksize = btrfs_inode_sectorsize(BTRFS_I(inode));
3305         int ret;
3306
3307         /* Do not allow fallocate in ZONED mode */
3308         if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
3309                 return -EOPNOTSUPP;
3310
3311         alloc_start = round_down(offset, blocksize);
3312         alloc_end = round_up(offset + len, blocksize);
3313         cur_offset = alloc_start;
3314
3315         /* Make sure we aren't being give some crap mode */
3316         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3317                      FALLOC_FL_ZERO_RANGE))
3318                 return -EOPNOTSUPP;
3319
3320         if (mode & FALLOC_FL_PUNCH_HOLE)
3321                 return btrfs_punch_hole(inode, offset, len);
3322
3323         /*
3324          * Only trigger disk allocation, don't trigger qgroup reserve
3325          *
3326          * For qgroup space, it will be checked later.
3327          */
3328         if (!(mode & FALLOC_FL_ZERO_RANGE)) {
3329                 ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
3330                                                       alloc_end - alloc_start);
3331                 if (ret < 0)
3332                         return ret;
3333         }
3334
3335         btrfs_inode_lock(inode, 0);
3336
3337         if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
3338                 ret = inode_newsize_ok(inode, offset + len);
3339                 if (ret)
3340                         goto out;
3341         }
3342
3343         /*
3344          * TODO: Move these two operations after we have checked
3345          * accurate reserved space, or fallocate can still fail but
3346          * with page truncated or size expanded.
3347          *
3348          * But that's a minor problem and won't do much harm BTW.
3349          */
3350         if (alloc_start > inode->i_size) {
3351                 ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode),
3352                                         alloc_start);
3353                 if (ret)
3354                         goto out;
3355         } else if (offset + len > inode->i_size) {
3356                 /*
3357                  * If we are fallocating from the end of the file onward we
3358                  * need to zero out the end of the block if i_size lands in the
3359                  * middle of a block.
3360                  */
3361                 ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0);
3362                 if (ret)
3363                         goto out;
3364         }
3365
3366         /*
3367          * wait for ordered IO before we have any locks.  We'll loop again
3368          * below with the locks held.
3369          */
3370         ret = btrfs_wait_ordered_range(inode, alloc_start,
3371                                        alloc_end - alloc_start);
3372         if (ret)
3373                 goto out;
3374
3375         if (mode & FALLOC_FL_ZERO_RANGE) {
3376                 ret = btrfs_zero_range(inode, offset, len, mode);
3377                 inode_unlock(inode);
3378                 return ret;
3379         }
3380
3381         locked_end = alloc_end - 1;
3382         while (1) {
3383                 struct btrfs_ordered_extent *ordered;
3384
3385                 /* the extent lock is ordered inside the running
3386                  * transaction
3387                  */
3388                 lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
3389                                  locked_end, &cached_state);
3390                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode),
3391                                                             locked_end);
3392
3393                 if (ordered &&
3394                     ordered->file_offset + ordered->num_bytes > alloc_start &&
3395                     ordered->file_offset < alloc_end) {
3396                         btrfs_put_ordered_extent(ordered);
3397                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
3398                                              alloc_start, locked_end,
3399                                              &cached_state);
3400                         /*
3401                          * we can't wait on the range with the transaction
3402                          * running or with the extent lock held
3403                          */
3404                         ret = btrfs_wait_ordered_range(inode, alloc_start,
3405                                                        alloc_end - alloc_start);
3406                         if (ret)
3407                                 goto out;
3408                 } else {
3409                         if (ordered)
3410                                 btrfs_put_ordered_extent(ordered);
3411                         break;
3412                 }
3413         }
3414
3415         /* First, check if we exceed the qgroup limit */
3416         INIT_LIST_HEAD(&reserve_list);
3417         while (cur_offset < alloc_end) {
3418                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
3419                                       alloc_end - cur_offset);
3420                 if (IS_ERR(em)) {
3421                         ret = PTR_ERR(em);
3422                         break;
3423                 }
3424                 last_byte = min(extent_map_end(em), alloc_end);
3425                 actual_end = min_t(u64, extent_map_end(em), offset + len);
3426                 last_byte = ALIGN(last_byte, blocksize);
3427                 if (em->block_start == EXTENT_MAP_HOLE ||
3428                     (cur_offset >= inode->i_size &&
3429                      !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
3430                         ret = add_falloc_range(&reserve_list, cur_offset,
3431                                                last_byte - cur_offset);
3432                         if (ret < 0) {
3433                                 free_extent_map(em);
3434                                 break;
3435                         }
3436                         ret = btrfs_qgroup_reserve_data(BTRFS_I(inode),
3437                                         &data_reserved, cur_offset,
3438                                         last_byte - cur_offset);
3439                         if (ret < 0) {
3440                                 cur_offset = last_byte;
3441                                 free_extent_map(em);
3442                                 break;
3443                         }
3444                 } else {
3445                         /*
3446                          * Do not need to reserve unwritten extent for this
3447                          * range, free reserved data space first, otherwise
3448                          * it'll result in false ENOSPC error.
3449                          */
3450                         btrfs_free_reserved_data_space(BTRFS_I(inode),
3451                                 data_reserved, cur_offset,
3452                                 last_byte - cur_offset);
3453                 }
3454                 free_extent_map(em);
3455                 cur_offset = last_byte;
3456         }
3457
3458         /*
3459          * If ret is still 0, means we're OK to fallocate.
3460          * Or just cleanup the list and exit.
3461          */
3462         list_for_each_entry_safe(range, tmp, &reserve_list, list) {
3463                 if (!ret)
3464                         ret = btrfs_prealloc_file_range(inode, mode,
3465                                         range->start,
3466                                         range->len, i_blocksize(inode),
3467                                         offset + len, &alloc_hint);
3468                 else
3469                         btrfs_free_reserved_data_space(BTRFS_I(inode),
3470                                         data_reserved, range->start,
3471                                         range->len);
3472                 list_del(&range->list);
3473                 kfree(range);
3474         }
3475         if (ret < 0)
3476                 goto out_unlock;
3477
3478         /*
3479          * We didn't need to allocate any more space, but we still extended the
3480          * size of the file so we need to update i_size and the inode item.
3481          */
3482         ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
3483 out_unlock:
3484         unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
3485                              &cached_state);
3486 out:
3487         inode_unlock(inode);
3488         /* Let go of our reservation. */
3489         if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE))
3490                 btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved,
3491                                 cur_offset, alloc_end - cur_offset);
3492         extent_changeset_free(data_reserved);
3493         return ret;
3494 }
3495
3496 static loff_t find_desired_extent(struct inode *inode, loff_t offset,
3497                                   int whence)
3498 {
3499         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3500         struct extent_map *em = NULL;
3501         struct extent_state *cached_state = NULL;
3502         loff_t i_size = inode->i_size;
3503         u64 lockstart;
3504         u64 lockend;
3505         u64 start;
3506         u64 len;
3507         int ret = 0;
3508
3509         if (i_size == 0 || offset >= i_size)
3510                 return -ENXIO;
3511
3512         /*
3513          * offset can be negative, in this case we start finding DATA/HOLE from
3514          * the very start of the file.
3515          */
3516         start = max_t(loff_t, 0, offset);
3517
3518         lockstart = round_down(start, fs_info->sectorsize);
3519         lockend = round_up(i_size, fs_info->sectorsize);
3520         if (lockend <= lockstart)
3521                 lockend = lockstart + fs_info->sectorsize;
3522         lockend--;
3523         len = lockend - lockstart + 1;
3524
3525         lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3526                          &cached_state);
3527
3528         while (start < i_size) {
3529                 em = btrfs_get_extent_fiemap(BTRFS_I(inode), start, len);
3530                 if (IS_ERR(em)) {
3531                         ret = PTR_ERR(em);
3532                         em = NULL;
3533                         break;
3534                 }
3535
3536                 if (whence == SEEK_HOLE &&
3537                     (em->block_start == EXTENT_MAP_HOLE ||
3538                      test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3539                         break;
3540                 else if (whence == SEEK_DATA &&
3541                            (em->block_start != EXTENT_MAP_HOLE &&
3542                             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
3543                         break;
3544
3545                 start = em->start + em->len;
3546                 free_extent_map(em);
3547                 em = NULL;
3548                 cond_resched();
3549         }
3550         free_extent_map(em);
3551         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
3552                              &cached_state);
3553         if (ret) {
3554                 offset = ret;
3555         } else {
3556                 if (whence == SEEK_DATA && start >= i_size)
3557                         offset = -ENXIO;
3558                 else
3559                         offset = min_t(loff_t, start, i_size);
3560         }
3561
3562         return offset;
3563 }
3564
3565 static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
3566 {
3567         struct inode *inode = file->f_mapping->host;
3568
3569         switch (whence) {
3570         default:
3571                 return generic_file_llseek(file, offset, whence);
3572         case SEEK_DATA:
3573         case SEEK_HOLE:
3574                 btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
3575                 offset = find_desired_extent(inode, offset, whence);
3576                 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
3577                 break;
3578         }
3579
3580         if (offset < 0)
3581                 return offset;
3582
3583         return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
3584 }
3585
3586 static int btrfs_file_open(struct inode *inode, struct file *filp)
3587 {
3588         filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
3589         return generic_file_open(inode, filp);
3590 }
3591
3592 static int check_direct_read(struct btrfs_fs_info *fs_info,
3593                              const struct iov_iter *iter, loff_t offset)
3594 {
3595         int ret;
3596         int i, seg;
3597
3598         ret = check_direct_IO(fs_info, iter, offset);
3599         if (ret < 0)
3600                 return ret;
3601
3602         if (!iter_is_iovec(iter))
3603                 return 0;
3604
3605         for (seg = 0; seg < iter->nr_segs; seg++)
3606                 for (i = seg + 1; i < iter->nr_segs; i++)
3607                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
3608                                 return -EINVAL;
3609         return 0;
3610 }
3611
3612 static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
3613 {
3614         struct inode *inode = file_inode(iocb->ki_filp);
3615         ssize_t ret;
3616
3617         if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
3618                 return 0;
3619
3620         btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
3621         ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops, 0);
3622         btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
3623         return ret;
3624 }
3625
3626 static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
3627 {
3628         ssize_t ret = 0;
3629
3630         if (iocb->ki_flags & IOCB_DIRECT) {
3631                 ret = btrfs_direct_read(iocb, to);
3632                 if (ret < 0 || !iov_iter_count(to) ||
3633                     iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))
3634                         return ret;
3635         }
3636
3637         return filemap_read(iocb, to, ret);
3638 }
3639
3640 const struct file_operations btrfs_file_operations = {
3641         .llseek         = btrfs_file_llseek,
3642         .read_iter      = btrfs_file_read_iter,
3643         .splice_read    = generic_file_splice_read,
3644         .write_iter     = btrfs_file_write_iter,
3645         .splice_write   = iter_file_splice_write,
3646         .mmap           = btrfs_file_mmap,
3647         .open           = btrfs_file_open,
3648         .release        = btrfs_release_file,
3649         .fsync          = btrfs_sync_file,
3650         .fallocate      = btrfs_fallocate,
3651         .unlocked_ioctl = btrfs_ioctl,
3652 #ifdef CONFIG_COMPAT
3653         .compat_ioctl   = btrfs_compat_ioctl,
3654 #endif
3655         .remap_file_range = btrfs_remap_file_range,
3656 };
3657
3658 void __cold btrfs_auto_defrag_exit(void)
3659 {
3660         kmem_cache_destroy(btrfs_inode_defrag_cachep);
3661 }
3662
3663 int __init btrfs_auto_defrag_init(void)
3664 {
3665         btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
3666                                         sizeof(struct inode_defrag), 0,
3667                                         SLAB_MEM_SPREAD,
3668                                         NULL);
3669         if (!btrfs_inode_defrag_cachep)
3670                 return -ENOMEM;
3671
3672         return 0;
3673 }
3674
3675 int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
3676 {
3677         int ret;
3678
3679         /*
3680          * So with compression we will find and lock a dirty page and clear the
3681          * first one as dirty, setup an async extent, and immediately return
3682          * with the entire range locked but with nobody actually marked with
3683          * writeback.  So we can't just filemap_write_and_wait_range() and
3684          * expect it to work since it will just kick off a thread to do the
3685          * actual work.  So we need to call filemap_fdatawrite_range _again_
3686          * since it will wait on the page lock, which won't be unlocked until
3687          * after the pages have been marked as writeback and so we're good to go
3688          * from there.  We have to do this otherwise we'll miss the ordered
3689          * extents and that results in badness.  Please Josef, do not think you
3690          * know better and pull this out at some point in the future, it is
3691          * right and you are wrong.
3692          */
3693         ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3694         if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
3695                              &BTRFS_I(inode)->runtime_flags))
3696                 ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
3697
3698         return ret;
3699 }