1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/pagemap.h> 21 #include <linux/highmem.h> 22 #include <linux/time.h> 23 #include <linux/init.h> 24 #include <linux/string.h> 25 #include <linux/smp_lock.h> 26 #include <linux/backing-dev.h> 27 #include <linux/mpage.h> 28 #include <linux/swap.h> 29 #include <linux/writeback.h> 30 #include <linux/statfs.h> 31 #include <linux/compat.h> 32 #include "ctree.h" 33 #include "disk-io.h" 34 #include "transaction.h" 35 #include "btrfs_inode.h" 36 #include "ioctl.h" 37 #include "print-tree.h" 38 #include "tree-log.h" 39 #include "locking.h" 40 #include "compat.h" 41 42 43 /* simple helper to fault in pages and copy. This should go away 44 * and be replaced with calls into generic code. 45 */ 46 static noinline int btrfs_copy_from_user(loff_t pos, int num_pages, 47 int write_bytes, 48 struct page **prepared_pages, 49 const char __user *buf) 50 { 51 long page_fault = 0; 52 int i; 53 int offset = pos & (PAGE_CACHE_SIZE - 1); 54 55 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) { 56 size_t count = min_t(size_t, 57 PAGE_CACHE_SIZE - offset, write_bytes); 58 struct page *page = prepared_pages[i]; 59 fault_in_pages_readable(buf, count); 60 61 /* Copy data from userspace to the current page */ 62 kmap(page); 63 page_fault = __copy_from_user(page_address(page) + offset, 64 buf, count); 65 /* Flush processor's dcache for this page */ 66 flush_dcache_page(page); 67 kunmap(page); 68 buf += count; 69 write_bytes -= count; 70 71 if (page_fault) 72 break; 73 } 74 return page_fault ? -EFAULT : 0; 75 } 76 77 /* 78 * unlocks pages after btrfs_file_write is done with them 79 */ 80 static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages) 81 { 82 size_t i; 83 for (i = 0; i < num_pages; i++) { 84 if (!pages[i]) 85 break; 86 /* page checked is some magic around finding pages that 87 * have been modified without going through btrfs_set_page_dirty 88 * clear it here 89 */ 90 ClearPageChecked(pages[i]); 91 unlock_page(pages[i]); 92 mark_page_accessed(pages[i]); 93 page_cache_release(pages[i]); 94 } 95 } 96 97 /* 98 * after copy_from_user, pages need to be dirtied and we need to make 99 * sure holes are created between the current EOF and the start of 100 * any next extents (if required). 101 * 102 * this also makes the decision about creating an inline extent vs 103 * doing real data extents, marking pages dirty and delalloc as required. 104 */ 105 static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans, 106 struct btrfs_root *root, 107 struct file *file, 108 struct page **pages, 109 size_t num_pages, 110 loff_t pos, 111 size_t write_bytes) 112 { 113 int err = 0; 114 int i; 115 struct inode *inode = fdentry(file)->d_inode; 116 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; 117 u64 hint_byte; 118 u64 num_bytes; 119 u64 start_pos; 120 u64 end_of_last_block; 121 u64 end_pos = pos + write_bytes; 122 loff_t isize = i_size_read(inode); 123 124 start_pos = pos & ~((u64)root->sectorsize - 1); 125 num_bytes = (write_bytes + pos - start_pos + 126 root->sectorsize - 1) & ~((u64)root->sectorsize - 1); 127 128 end_of_last_block = start_pos + num_bytes - 1; 129 130 lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS); 131 trans = btrfs_join_transaction(root, 1); 132 if (!trans) { 133 err = -ENOMEM; 134 goto out_unlock; 135 } 136 btrfs_set_trans_block_group(trans, inode); 137 hint_byte = 0; 138 139 set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS); 140 141 /* check for reserved extents on each page, we don't want 142 * to reset the delalloc bit on things that already have 143 * extents reserved. 144 */ 145 btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block); 146 for (i = 0; i < num_pages; i++) { 147 struct page *p = pages[i]; 148 SetPageUptodate(p); 149 ClearPageChecked(p); 150 set_page_dirty(p); 151 } 152 if (end_pos > isize) { 153 i_size_write(inode, end_pos); 154 btrfs_update_inode(trans, root, inode); 155 } 156 err = btrfs_end_transaction(trans, root); 157 out_unlock: 158 unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS); 159 return err; 160 } 161 162 /* 163 * this drops all the extents in the cache that intersect the range 164 * [start, end]. Existing extents are split as required. 165 */ 166 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, 167 int skip_pinned) 168 { 169 struct extent_map *em; 170 struct extent_map *split = NULL; 171 struct extent_map *split2 = NULL; 172 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 173 u64 len = end - start + 1; 174 int ret; 175 int testend = 1; 176 unsigned long flags; 177 int compressed = 0; 178 179 WARN_ON(end < start); 180 if (end == (u64)-1) { 181 len = (u64)-1; 182 testend = 0; 183 } 184 while (1) { 185 if (!split) 186 split = alloc_extent_map(GFP_NOFS); 187 if (!split2) 188 split2 = alloc_extent_map(GFP_NOFS); 189 190 spin_lock(&em_tree->lock); 191 em = lookup_extent_mapping(em_tree, start, len); 192 if (!em) { 193 spin_unlock(&em_tree->lock); 194 break; 195 } 196 flags = em->flags; 197 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) { 198 spin_unlock(&em_tree->lock); 199 if (em->start <= start && 200 (!testend || em->start + em->len >= start + len)) { 201 free_extent_map(em); 202 break; 203 } 204 if (start < em->start) { 205 len = em->start - start; 206 } else { 207 len = start + len - (em->start + em->len); 208 start = em->start + em->len; 209 } 210 free_extent_map(em); 211 continue; 212 } 213 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); 214 clear_bit(EXTENT_FLAG_PINNED, &em->flags); 215 remove_extent_mapping(em_tree, em); 216 217 if (em->block_start < EXTENT_MAP_LAST_BYTE && 218 em->start < start) { 219 split->start = em->start; 220 split->len = start - em->start; 221 split->orig_start = em->orig_start; 222 split->block_start = em->block_start; 223 224 if (compressed) 225 split->block_len = em->block_len; 226 else 227 split->block_len = split->len; 228 229 split->bdev = em->bdev; 230 split->flags = flags; 231 ret = add_extent_mapping(em_tree, split); 232 BUG_ON(ret); 233 free_extent_map(split); 234 split = split2; 235 split2 = NULL; 236 } 237 if (em->block_start < EXTENT_MAP_LAST_BYTE && 238 testend && em->start + em->len > start + len) { 239 u64 diff = start + len - em->start; 240 241 split->start = start + len; 242 split->len = em->start + em->len - (start + len); 243 split->bdev = em->bdev; 244 split->flags = flags; 245 246 if (compressed) { 247 split->block_len = em->block_len; 248 split->block_start = em->block_start; 249 split->orig_start = em->orig_start; 250 } else { 251 split->block_len = split->len; 252 split->block_start = em->block_start + diff; 253 split->orig_start = split->start; 254 } 255 256 ret = add_extent_mapping(em_tree, split); 257 BUG_ON(ret); 258 free_extent_map(split); 259 split = NULL; 260 } 261 spin_unlock(&em_tree->lock); 262 263 /* once for us */ 264 free_extent_map(em); 265 /* once for the tree*/ 266 free_extent_map(em); 267 } 268 if (split) 269 free_extent_map(split); 270 if (split2) 271 free_extent_map(split2); 272 return 0; 273 } 274 275 /* 276 * this is very complex, but the basic idea is to drop all extents 277 * in the range start - end. hint_block is filled in with a block number 278 * that would be a good hint to the block allocator for this file. 279 * 280 * If an extent intersects the range but is not entirely inside the range 281 * it is either truncated or split. Anything entirely inside the range 282 * is deleted from the tree. 283 * 284 * inline_limit is used to tell this code which offsets in the file to keep 285 * if they contain inline extents. 286 */ 287 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans, 288 struct btrfs_root *root, struct inode *inode, 289 u64 start, u64 end, u64 locked_end, 290 u64 inline_limit, u64 *hint_byte) 291 { 292 u64 extent_end = 0; 293 u64 search_start = start; 294 u64 leaf_start; 295 u64 ram_bytes = 0; 296 u64 orig_parent = 0; 297 u64 disk_bytenr = 0; 298 u64 orig_locked_end = locked_end; 299 u8 compression; 300 u8 encryption; 301 u16 other_encoding = 0; 302 u64 root_gen; 303 u64 root_owner; 304 struct extent_buffer *leaf; 305 struct btrfs_file_extent_item *extent; 306 struct btrfs_path *path; 307 struct btrfs_key key; 308 struct btrfs_file_extent_item old; 309 int keep; 310 int slot; 311 int bookend; 312 int found_type = 0; 313 int found_extent; 314 int found_inline; 315 int recow; 316 int ret; 317 318 inline_limit = 0; 319 btrfs_drop_extent_cache(inode, start, end - 1, 0); 320 321 path = btrfs_alloc_path(); 322 if (!path) 323 return -ENOMEM; 324 while (1) { 325 recow = 0; 326 btrfs_release_path(root, path); 327 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, 328 search_start, -1); 329 if (ret < 0) 330 goto out; 331 if (ret > 0) { 332 if (path->slots[0] == 0) { 333 ret = 0; 334 goto out; 335 } 336 path->slots[0]--; 337 } 338 next_slot: 339 keep = 0; 340 bookend = 0; 341 found_extent = 0; 342 found_inline = 0; 343 leaf_start = 0; 344 root_gen = 0; 345 root_owner = 0; 346 compression = 0; 347 encryption = 0; 348 extent = NULL; 349 leaf = path->nodes[0]; 350 slot = path->slots[0]; 351 ret = 0; 352 btrfs_item_key_to_cpu(leaf, &key, slot); 353 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY && 354 key.offset >= end) { 355 goto out; 356 } 357 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY || 358 key.objectid != inode->i_ino) { 359 goto out; 360 } 361 if (recow) { 362 search_start = max(key.offset, start); 363 continue; 364 } 365 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) { 366 extent = btrfs_item_ptr(leaf, slot, 367 struct btrfs_file_extent_item); 368 found_type = btrfs_file_extent_type(leaf, extent); 369 compression = btrfs_file_extent_compression(leaf, 370 extent); 371 encryption = btrfs_file_extent_encryption(leaf, 372 extent); 373 other_encoding = btrfs_file_extent_other_encoding(leaf, 374 extent); 375 if (found_type == BTRFS_FILE_EXTENT_REG || 376 found_type == BTRFS_FILE_EXTENT_PREALLOC) { 377 extent_end = 378 btrfs_file_extent_disk_bytenr(leaf, 379 extent); 380 if (extent_end) 381 *hint_byte = extent_end; 382 383 extent_end = key.offset + 384 btrfs_file_extent_num_bytes(leaf, extent); 385 ram_bytes = btrfs_file_extent_ram_bytes(leaf, 386 extent); 387 found_extent = 1; 388 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { 389 found_inline = 1; 390 extent_end = key.offset + 391 btrfs_file_extent_inline_len(leaf, extent); 392 } 393 } else { 394 extent_end = search_start; 395 } 396 397 /* we found nothing we can drop */ 398 if ((!found_extent && !found_inline) || 399 search_start >= extent_end) { 400 int nextret; 401 u32 nritems; 402 nritems = btrfs_header_nritems(leaf); 403 if (slot >= nritems - 1) { 404 nextret = btrfs_next_leaf(root, path); 405 if (nextret) 406 goto out; 407 recow = 1; 408 } else { 409 path->slots[0]++; 410 } 411 goto next_slot; 412 } 413 414 if (end <= extent_end && start >= key.offset && found_inline) 415 *hint_byte = EXTENT_MAP_INLINE; 416 417 if (found_extent) { 418 read_extent_buffer(leaf, &old, (unsigned long)extent, 419 sizeof(old)); 420 root_gen = btrfs_header_generation(leaf); 421 root_owner = btrfs_header_owner(leaf); 422 leaf_start = leaf->start; 423 } 424 425 if (end < extent_end && end >= key.offset) { 426 bookend = 1; 427 if (found_inline && start <= key.offset) 428 keep = 1; 429 } 430 431 if (bookend && found_extent) { 432 if (locked_end < extent_end) { 433 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 434 locked_end, extent_end - 1, 435 GFP_NOFS); 436 if (!ret) { 437 btrfs_release_path(root, path); 438 lock_extent(&BTRFS_I(inode)->io_tree, 439 locked_end, extent_end - 1, 440 GFP_NOFS); 441 locked_end = extent_end; 442 continue; 443 } 444 locked_end = extent_end; 445 } 446 orig_parent = path->nodes[0]->start; 447 disk_bytenr = le64_to_cpu(old.disk_bytenr); 448 if (disk_bytenr != 0) { 449 ret = btrfs_inc_extent_ref(trans, root, 450 disk_bytenr, 451 le64_to_cpu(old.disk_num_bytes), 452 orig_parent, root->root_key.objectid, 453 trans->transid, inode->i_ino); 454 BUG_ON(ret); 455 } 456 } 457 458 if (found_inline) { 459 u64 mask = root->sectorsize - 1; 460 search_start = (extent_end + mask) & ~mask; 461 } else 462 search_start = extent_end; 463 464 /* truncate existing extent */ 465 if (start > key.offset) { 466 u64 new_num; 467 u64 old_num; 468 keep = 1; 469 WARN_ON(start & (root->sectorsize - 1)); 470 if (found_extent) { 471 new_num = start - key.offset; 472 old_num = btrfs_file_extent_num_bytes(leaf, 473 extent); 474 *hint_byte = 475 btrfs_file_extent_disk_bytenr(leaf, 476 extent); 477 if (btrfs_file_extent_disk_bytenr(leaf, 478 extent)) { 479 inode_sub_bytes(inode, old_num - 480 new_num); 481 } 482 btrfs_set_file_extent_num_bytes(leaf, 483 extent, new_num); 484 btrfs_mark_buffer_dirty(leaf); 485 } else if (key.offset < inline_limit && 486 (end > extent_end) && 487 (inline_limit < extent_end)) { 488 u32 new_size; 489 new_size = btrfs_file_extent_calc_inline_size( 490 inline_limit - key.offset); 491 inode_sub_bytes(inode, extent_end - 492 inline_limit); 493 btrfs_set_file_extent_ram_bytes(leaf, extent, 494 new_size); 495 if (!compression && !encryption) { 496 btrfs_truncate_item(trans, root, path, 497 new_size, 1); 498 } 499 } 500 } 501 /* delete the entire extent */ 502 if (!keep) { 503 if (found_inline) 504 inode_sub_bytes(inode, extent_end - 505 key.offset); 506 ret = btrfs_del_item(trans, root, path); 507 /* TODO update progress marker and return */ 508 BUG_ON(ret); 509 extent = NULL; 510 btrfs_release_path(root, path); 511 /* the extent will be freed later */ 512 } 513 if (bookend && found_inline && start <= key.offset) { 514 u32 new_size; 515 new_size = btrfs_file_extent_calc_inline_size( 516 extent_end - end); 517 inode_sub_bytes(inode, end - key.offset); 518 btrfs_set_file_extent_ram_bytes(leaf, extent, 519 new_size); 520 if (!compression && !encryption) 521 ret = btrfs_truncate_item(trans, root, path, 522 new_size, 0); 523 BUG_ON(ret); 524 } 525 /* create bookend, splitting the extent in two */ 526 if (bookend && found_extent) { 527 struct btrfs_key ins; 528 ins.objectid = inode->i_ino; 529 ins.offset = end; 530 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY); 531 532 btrfs_release_path(root, path); 533 path->leave_spinning = 1; 534 ret = btrfs_insert_empty_item(trans, root, path, &ins, 535 sizeof(*extent)); 536 BUG_ON(ret); 537 538 leaf = path->nodes[0]; 539 extent = btrfs_item_ptr(leaf, path->slots[0], 540 struct btrfs_file_extent_item); 541 write_extent_buffer(leaf, &old, 542 (unsigned long)extent, sizeof(old)); 543 544 btrfs_set_file_extent_compression(leaf, extent, 545 compression); 546 btrfs_set_file_extent_encryption(leaf, extent, 547 encryption); 548 btrfs_set_file_extent_other_encoding(leaf, extent, 549 other_encoding); 550 btrfs_set_file_extent_offset(leaf, extent, 551 le64_to_cpu(old.offset) + end - key.offset); 552 WARN_ON(le64_to_cpu(old.num_bytes) < 553 (extent_end - end)); 554 btrfs_set_file_extent_num_bytes(leaf, extent, 555 extent_end - end); 556 557 /* 558 * set the ram bytes to the size of the full extent 559 * before splitting. This is a worst case flag, 560 * but its the best we can do because we don't know 561 * how splitting affects compression 562 */ 563 btrfs_set_file_extent_ram_bytes(leaf, extent, 564 ram_bytes); 565 btrfs_set_file_extent_type(leaf, extent, found_type); 566 567 btrfs_unlock_up_safe(path, 1); 568 btrfs_mark_buffer_dirty(path->nodes[0]); 569 btrfs_set_lock_blocking(path->nodes[0]); 570 571 if (disk_bytenr != 0) { 572 ret = btrfs_update_extent_ref(trans, root, 573 disk_bytenr, 574 le64_to_cpu(old.disk_num_bytes), 575 orig_parent, 576 leaf->start, 577 root->root_key.objectid, 578 trans->transid, ins.objectid); 579 580 BUG_ON(ret); 581 } 582 path->leave_spinning = 0; 583 btrfs_release_path(root, path); 584 if (disk_bytenr != 0) 585 inode_add_bytes(inode, extent_end - end); 586 } 587 588 if (found_extent && !keep) { 589 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr); 590 591 if (old_disk_bytenr != 0) { 592 inode_sub_bytes(inode, 593 le64_to_cpu(old.num_bytes)); 594 ret = btrfs_free_extent(trans, root, 595 old_disk_bytenr, 596 le64_to_cpu(old.disk_num_bytes), 597 leaf_start, root_owner, 598 root_gen, key.objectid, 0); 599 BUG_ON(ret); 600 *hint_byte = old_disk_bytenr; 601 } 602 } 603 604 if (search_start >= end) { 605 ret = 0; 606 goto out; 607 } 608 } 609 out: 610 btrfs_free_path(path); 611 if (locked_end > orig_locked_end) { 612 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end, 613 locked_end - 1, GFP_NOFS); 614 } 615 return ret; 616 } 617 618 static int extent_mergeable(struct extent_buffer *leaf, int slot, 619 u64 objectid, u64 bytenr, u64 *start, u64 *end) 620 { 621 struct btrfs_file_extent_item *fi; 622 struct btrfs_key key; 623 u64 extent_end; 624 625 if (slot < 0 || slot >= btrfs_header_nritems(leaf)) 626 return 0; 627 628 btrfs_item_key_to_cpu(leaf, &key, slot); 629 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) 630 return 0; 631 632 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); 633 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || 634 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || 635 btrfs_file_extent_compression(leaf, fi) || 636 btrfs_file_extent_encryption(leaf, fi) || 637 btrfs_file_extent_other_encoding(leaf, fi)) 638 return 0; 639 640 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 641 if ((*start && *start != key.offset) || (*end && *end != extent_end)) 642 return 0; 643 644 *start = key.offset; 645 *end = extent_end; 646 return 1; 647 } 648 649 /* 650 * Mark extent in the range start - end as written. 651 * 652 * This changes extent type from 'pre-allocated' to 'regular'. If only 653 * part of extent is marked as written, the extent will be split into 654 * two or three. 655 */ 656 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, 657 struct btrfs_root *root, 658 struct inode *inode, u64 start, u64 end) 659 { 660 struct extent_buffer *leaf; 661 struct btrfs_path *path; 662 struct btrfs_file_extent_item *fi; 663 struct btrfs_key key; 664 u64 bytenr; 665 u64 num_bytes; 666 u64 extent_end; 667 u64 extent_offset; 668 u64 other_start; 669 u64 other_end; 670 u64 split = start; 671 u64 locked_end = end; 672 u64 orig_parent; 673 int extent_type; 674 int split_end = 1; 675 int ret; 676 677 btrfs_drop_extent_cache(inode, start, end - 1, 0); 678 679 path = btrfs_alloc_path(); 680 BUG_ON(!path); 681 again: 682 key.objectid = inode->i_ino; 683 key.type = BTRFS_EXTENT_DATA_KEY; 684 if (split == start) 685 key.offset = split; 686 else 687 key.offset = split - 1; 688 689 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 690 if (ret > 0 && path->slots[0] > 0) 691 path->slots[0]--; 692 693 leaf = path->nodes[0]; 694 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 695 BUG_ON(key.objectid != inode->i_ino || 696 key.type != BTRFS_EXTENT_DATA_KEY); 697 fi = btrfs_item_ptr(leaf, path->slots[0], 698 struct btrfs_file_extent_item); 699 extent_type = btrfs_file_extent_type(leaf, fi); 700 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC); 701 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 702 BUG_ON(key.offset > start || extent_end < end); 703 704 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 705 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 706 extent_offset = btrfs_file_extent_offset(leaf, fi); 707 708 if (key.offset == start) 709 split = end; 710 711 if (key.offset == start && extent_end == end) { 712 int del_nr = 0; 713 int del_slot = 0; 714 u64 leaf_owner = btrfs_header_owner(leaf); 715 u64 leaf_gen = btrfs_header_generation(leaf); 716 other_start = end; 717 other_end = 0; 718 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, 719 bytenr, &other_start, &other_end)) { 720 extent_end = other_end; 721 del_slot = path->slots[0] + 1; 722 del_nr++; 723 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 724 leaf->start, leaf_owner, 725 leaf_gen, inode->i_ino, 0); 726 BUG_ON(ret); 727 } 728 other_start = 0; 729 other_end = start; 730 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino, 731 bytenr, &other_start, &other_end)) { 732 key.offset = other_start; 733 del_slot = path->slots[0]; 734 del_nr++; 735 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 736 leaf->start, leaf_owner, 737 leaf_gen, inode->i_ino, 0); 738 BUG_ON(ret); 739 } 740 split_end = 0; 741 if (del_nr == 0) { 742 btrfs_set_file_extent_type(leaf, fi, 743 BTRFS_FILE_EXTENT_REG); 744 goto done; 745 } 746 747 fi = btrfs_item_ptr(leaf, del_slot - 1, 748 struct btrfs_file_extent_item); 749 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG); 750 btrfs_set_file_extent_num_bytes(leaf, fi, 751 extent_end - key.offset); 752 btrfs_mark_buffer_dirty(leaf); 753 754 ret = btrfs_del_items(trans, root, path, del_slot, del_nr); 755 BUG_ON(ret); 756 goto release; 757 } else if (split == start) { 758 if (locked_end < extent_end) { 759 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 760 locked_end, extent_end - 1, GFP_NOFS); 761 if (!ret) { 762 btrfs_release_path(root, path); 763 lock_extent(&BTRFS_I(inode)->io_tree, 764 locked_end, extent_end - 1, GFP_NOFS); 765 locked_end = extent_end; 766 goto again; 767 } 768 locked_end = extent_end; 769 } 770 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset); 771 extent_offset += split - key.offset; 772 } else { 773 BUG_ON(key.offset != start); 774 btrfs_set_file_extent_offset(leaf, fi, extent_offset + 775 split - key.offset); 776 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split); 777 key.offset = split; 778 btrfs_set_item_key_safe(trans, root, path, &key); 779 extent_end = split; 780 } 781 782 if (extent_end == end) { 783 split_end = 0; 784 extent_type = BTRFS_FILE_EXTENT_REG; 785 } 786 if (extent_end == end && split == start) { 787 other_start = end; 788 other_end = 0; 789 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, 790 bytenr, &other_start, &other_end)) { 791 path->slots[0]++; 792 fi = btrfs_item_ptr(leaf, path->slots[0], 793 struct btrfs_file_extent_item); 794 key.offset = split; 795 btrfs_set_item_key_safe(trans, root, path, &key); 796 btrfs_set_file_extent_offset(leaf, fi, extent_offset); 797 btrfs_set_file_extent_num_bytes(leaf, fi, 798 other_end - split); 799 goto done; 800 } 801 } 802 if (extent_end == end && split == end) { 803 other_start = 0; 804 other_end = start; 805 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino, 806 bytenr, &other_start, &other_end)) { 807 path->slots[0]--; 808 fi = btrfs_item_ptr(leaf, path->slots[0], 809 struct btrfs_file_extent_item); 810 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - 811 other_start); 812 goto done; 813 } 814 } 815 816 btrfs_mark_buffer_dirty(leaf); 817 818 orig_parent = leaf->start; 819 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 820 orig_parent, root->root_key.objectid, 821 trans->transid, inode->i_ino); 822 BUG_ON(ret); 823 btrfs_release_path(root, path); 824 825 key.offset = start; 826 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi)); 827 BUG_ON(ret); 828 829 leaf = path->nodes[0]; 830 fi = btrfs_item_ptr(leaf, path->slots[0], 831 struct btrfs_file_extent_item); 832 btrfs_set_file_extent_generation(leaf, fi, trans->transid); 833 btrfs_set_file_extent_type(leaf, fi, extent_type); 834 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr); 835 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes); 836 btrfs_set_file_extent_offset(leaf, fi, extent_offset); 837 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset); 838 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); 839 btrfs_set_file_extent_compression(leaf, fi, 0); 840 btrfs_set_file_extent_encryption(leaf, fi, 0); 841 btrfs_set_file_extent_other_encoding(leaf, fi, 0); 842 843 if (orig_parent != leaf->start) { 844 ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes, 845 orig_parent, leaf->start, 846 root->root_key.objectid, 847 trans->transid, inode->i_ino); 848 BUG_ON(ret); 849 } 850 done: 851 btrfs_mark_buffer_dirty(leaf); 852 853 release: 854 btrfs_release_path(root, path); 855 if (split_end && split == start) { 856 split = end; 857 goto again; 858 } 859 if (locked_end > end) { 860 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1, 861 GFP_NOFS); 862 } 863 btrfs_free_path(path); 864 return 0; 865 } 866 867 /* 868 * this gets pages into the page cache and locks them down, it also properly 869 * waits for data=ordered extents to finish before allowing the pages to be 870 * modified. 871 */ 872 static noinline int prepare_pages(struct btrfs_root *root, struct file *file, 873 struct page **pages, size_t num_pages, 874 loff_t pos, unsigned long first_index, 875 unsigned long last_index, size_t write_bytes) 876 { 877 int i; 878 unsigned long index = pos >> PAGE_CACHE_SHIFT; 879 struct inode *inode = fdentry(file)->d_inode; 880 int err = 0; 881 u64 start_pos; 882 u64 last_pos; 883 884 start_pos = pos & ~((u64)root->sectorsize - 1); 885 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; 886 887 if (start_pos > inode->i_size) { 888 err = btrfs_cont_expand(inode, start_pos); 889 if (err) 890 return err; 891 } 892 893 memset(pages, 0, num_pages * sizeof(struct page *)); 894 again: 895 for (i = 0; i < num_pages; i++) { 896 pages[i] = grab_cache_page(inode->i_mapping, index + i); 897 if (!pages[i]) { 898 err = -ENOMEM; 899 BUG_ON(1); 900 } 901 wait_on_page_writeback(pages[i]); 902 } 903 if (start_pos < inode->i_size) { 904 struct btrfs_ordered_extent *ordered; 905 lock_extent(&BTRFS_I(inode)->io_tree, 906 start_pos, last_pos - 1, GFP_NOFS); 907 ordered = btrfs_lookup_first_ordered_extent(inode, 908 last_pos - 1); 909 if (ordered && 910 ordered->file_offset + ordered->len > start_pos && 911 ordered->file_offset < last_pos) { 912 btrfs_put_ordered_extent(ordered); 913 unlock_extent(&BTRFS_I(inode)->io_tree, 914 start_pos, last_pos - 1, GFP_NOFS); 915 for (i = 0; i < num_pages; i++) { 916 unlock_page(pages[i]); 917 page_cache_release(pages[i]); 918 } 919 btrfs_wait_ordered_range(inode, start_pos, 920 last_pos - start_pos); 921 goto again; 922 } 923 if (ordered) 924 btrfs_put_ordered_extent(ordered); 925 926 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos, 927 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC, 928 GFP_NOFS); 929 unlock_extent(&BTRFS_I(inode)->io_tree, 930 start_pos, last_pos - 1, GFP_NOFS); 931 } 932 for (i = 0; i < num_pages; i++) { 933 clear_page_dirty_for_io(pages[i]); 934 set_page_extent_mapped(pages[i]); 935 WARN_ON(!PageLocked(pages[i])); 936 } 937 return 0; 938 } 939 940 static ssize_t btrfs_file_write(struct file *file, const char __user *buf, 941 size_t count, loff_t *ppos) 942 { 943 loff_t pos; 944 loff_t start_pos; 945 ssize_t num_written = 0; 946 ssize_t err = 0; 947 int ret = 0; 948 struct inode *inode = fdentry(file)->d_inode; 949 struct btrfs_root *root = BTRFS_I(inode)->root; 950 struct page **pages = NULL; 951 int nrptrs; 952 struct page *pinned[2]; 953 unsigned long first_index; 954 unsigned long last_index; 955 int will_write; 956 957 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) || 958 (file->f_flags & O_DIRECT)); 959 960 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, 961 PAGE_CACHE_SIZE / (sizeof(struct page *))); 962 pinned[0] = NULL; 963 pinned[1] = NULL; 964 965 pos = *ppos; 966 start_pos = pos; 967 968 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); 969 current->backing_dev_info = inode->i_mapping->backing_dev_info; 970 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); 971 if (err) 972 goto out_nolock; 973 if (count == 0) 974 goto out_nolock; 975 976 err = file_remove_suid(file); 977 if (err) 978 goto out_nolock; 979 file_update_time(file); 980 981 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); 982 983 mutex_lock(&inode->i_mutex); 984 BTRFS_I(inode)->sequence++; 985 first_index = pos >> PAGE_CACHE_SHIFT; 986 last_index = (pos + count) >> PAGE_CACHE_SHIFT; 987 988 /* 989 * there are lots of better ways to do this, but this code 990 * makes sure the first and last page in the file range are 991 * up to date and ready for cow 992 */ 993 if ((pos & (PAGE_CACHE_SIZE - 1))) { 994 pinned[0] = grab_cache_page(inode->i_mapping, first_index); 995 if (!PageUptodate(pinned[0])) { 996 ret = btrfs_readpage(NULL, pinned[0]); 997 BUG_ON(ret); 998 wait_on_page_locked(pinned[0]); 999 } else { 1000 unlock_page(pinned[0]); 1001 } 1002 } 1003 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { 1004 pinned[1] = grab_cache_page(inode->i_mapping, last_index); 1005 if (!PageUptodate(pinned[1])) { 1006 ret = btrfs_readpage(NULL, pinned[1]); 1007 BUG_ON(ret); 1008 wait_on_page_locked(pinned[1]); 1009 } else { 1010 unlock_page(pinned[1]); 1011 } 1012 } 1013 1014 while (count > 0) { 1015 size_t offset = pos & (PAGE_CACHE_SIZE - 1); 1016 size_t write_bytes = min(count, nrptrs * 1017 (size_t)PAGE_CACHE_SIZE - 1018 offset); 1019 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> 1020 PAGE_CACHE_SHIFT; 1021 1022 WARN_ON(num_pages > nrptrs); 1023 memset(pages, 0, sizeof(struct page *) * nrptrs); 1024 1025 ret = btrfs_check_data_free_space(root, inode, write_bytes); 1026 if (ret) 1027 goto out; 1028 1029 ret = prepare_pages(root, file, pages, num_pages, 1030 pos, first_index, last_index, 1031 write_bytes); 1032 if (ret) { 1033 btrfs_free_reserved_data_space(root, inode, 1034 write_bytes); 1035 goto out; 1036 } 1037 1038 ret = btrfs_copy_from_user(pos, num_pages, 1039 write_bytes, pages, buf); 1040 if (ret) { 1041 btrfs_free_reserved_data_space(root, inode, 1042 write_bytes); 1043 btrfs_drop_pages(pages, num_pages); 1044 goto out; 1045 } 1046 1047 ret = dirty_and_release_pages(NULL, root, file, pages, 1048 num_pages, pos, write_bytes); 1049 btrfs_drop_pages(pages, num_pages); 1050 if (ret) { 1051 btrfs_free_reserved_data_space(root, inode, 1052 write_bytes); 1053 goto out; 1054 } 1055 1056 if (will_write) { 1057 btrfs_fdatawrite_range(inode->i_mapping, pos, 1058 pos + write_bytes - 1, 1059 WB_SYNC_ALL); 1060 } else { 1061 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1062 num_pages); 1063 if (num_pages < 1064 (root->leafsize >> PAGE_CACHE_SHIFT) + 1) 1065 btrfs_btree_balance_dirty(root, 1); 1066 btrfs_throttle(root); 1067 } 1068 1069 buf += write_bytes; 1070 count -= write_bytes; 1071 pos += write_bytes; 1072 num_written += write_bytes; 1073 1074 cond_resched(); 1075 } 1076 out: 1077 mutex_unlock(&inode->i_mutex); 1078 if (ret) 1079 err = ret; 1080 1081 out_nolock: 1082 kfree(pages); 1083 if (pinned[0]) 1084 page_cache_release(pinned[0]); 1085 if (pinned[1]) 1086 page_cache_release(pinned[1]); 1087 *ppos = pos; 1088 1089 /* 1090 * we want to make sure fsync finds this change 1091 * but we haven't joined a transaction running right now. 1092 * 1093 * Later on, someone is sure to update the inode and get the 1094 * real transid recorded. 1095 * 1096 * We set last_trans now to the fs_info generation + 1, 1097 * this will either be one more than the running transaction 1098 * or the generation used for the next transaction if there isn't 1099 * one running right now. 1100 */ 1101 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1; 1102 1103 if (num_written > 0 && will_write) { 1104 struct btrfs_trans_handle *trans; 1105 1106 err = btrfs_wait_ordered_range(inode, start_pos, num_written); 1107 if (err) 1108 num_written = err; 1109 1110 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) { 1111 trans = btrfs_start_transaction(root, 1); 1112 ret = btrfs_log_dentry_safe(trans, root, 1113 file->f_dentry); 1114 if (ret == 0) { 1115 ret = btrfs_sync_log(trans, root); 1116 if (ret == 0) 1117 btrfs_end_transaction(trans, root); 1118 else 1119 btrfs_commit_transaction(trans, root); 1120 } else { 1121 btrfs_commit_transaction(trans, root); 1122 } 1123 } 1124 if (file->f_flags & O_DIRECT) { 1125 invalidate_mapping_pages(inode->i_mapping, 1126 start_pos >> PAGE_CACHE_SHIFT, 1127 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT); 1128 } 1129 } 1130 current->backing_dev_info = NULL; 1131 return num_written ? num_written : err; 1132 } 1133 1134 int btrfs_release_file(struct inode *inode, struct file *filp) 1135 { 1136 /* 1137 * ordered_data_close is set by settattr when we are about to truncate 1138 * a file from a non-zero size to a zero size. This tries to 1139 * flush down new bytes that may have been written if the 1140 * application were using truncate to replace a file in place. 1141 */ 1142 if (BTRFS_I(inode)->ordered_data_close) { 1143 BTRFS_I(inode)->ordered_data_close = 0; 1144 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode); 1145 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT) 1146 filemap_flush(inode->i_mapping); 1147 } 1148 if (filp->private_data) 1149 btrfs_ioctl_trans_end(filp); 1150 return 0; 1151 } 1152 1153 /* 1154 * fsync call for both files and directories. This logs the inode into 1155 * the tree log instead of forcing full commits whenever possible. 1156 * 1157 * It needs to call filemap_fdatawait so that all ordered extent updates are 1158 * in the metadata btree are up to date for copying to the log. 1159 * 1160 * It drops the inode mutex before doing the tree log commit. This is an 1161 * important optimization for directories because holding the mutex prevents 1162 * new operations on the dir while we write to disk. 1163 */ 1164 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync) 1165 { 1166 struct inode *inode = dentry->d_inode; 1167 struct btrfs_root *root = BTRFS_I(inode)->root; 1168 int ret = 0; 1169 struct btrfs_trans_handle *trans; 1170 1171 /* 1172 * check the transaction that last modified this inode 1173 * and see if its already been committed 1174 */ 1175 if (!BTRFS_I(inode)->last_trans) 1176 goto out; 1177 1178 mutex_lock(&root->fs_info->trans_mutex); 1179 if (BTRFS_I(inode)->last_trans <= 1180 root->fs_info->last_trans_committed) { 1181 BTRFS_I(inode)->last_trans = 0; 1182 mutex_unlock(&root->fs_info->trans_mutex); 1183 goto out; 1184 } 1185 mutex_unlock(&root->fs_info->trans_mutex); 1186 1187 root->log_batch++; 1188 filemap_fdatawrite(inode->i_mapping); 1189 btrfs_wait_ordered_range(inode, 0, (u64)-1); 1190 root->log_batch++; 1191 1192 /* 1193 * ok we haven't committed the transaction yet, lets do a commit 1194 */ 1195 if (file && file->private_data) 1196 btrfs_ioctl_trans_end(file); 1197 1198 trans = btrfs_start_transaction(root, 1); 1199 if (!trans) { 1200 ret = -ENOMEM; 1201 goto out; 1202 } 1203 1204 ret = btrfs_log_dentry_safe(trans, root, dentry); 1205 if (ret < 0) 1206 goto out; 1207 1208 /* we've logged all the items and now have a consistent 1209 * version of the file in the log. It is possible that 1210 * someone will come in and modify the file, but that's 1211 * fine because the log is consistent on disk, and we 1212 * have references to all of the file's extents 1213 * 1214 * It is possible that someone will come in and log the 1215 * file again, but that will end up using the synchronization 1216 * inside btrfs_sync_log to keep things safe. 1217 */ 1218 mutex_unlock(&dentry->d_inode->i_mutex); 1219 1220 if (ret > 0) { 1221 ret = btrfs_commit_transaction(trans, root); 1222 } else { 1223 ret = btrfs_sync_log(trans, root); 1224 if (ret == 0) 1225 ret = btrfs_end_transaction(trans, root); 1226 else 1227 ret = btrfs_commit_transaction(trans, root); 1228 } 1229 mutex_lock(&dentry->d_inode->i_mutex); 1230 out: 1231 return ret > 0 ? EIO : ret; 1232 } 1233 1234 static struct vm_operations_struct btrfs_file_vm_ops = { 1235 .fault = filemap_fault, 1236 .page_mkwrite = btrfs_page_mkwrite, 1237 }; 1238 1239 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) 1240 { 1241 vma->vm_ops = &btrfs_file_vm_ops; 1242 file_accessed(filp); 1243 return 0; 1244 } 1245 1246 struct file_operations btrfs_file_operations = { 1247 .llseek = generic_file_llseek, 1248 .read = do_sync_read, 1249 .aio_read = generic_file_aio_read, 1250 .splice_read = generic_file_splice_read, 1251 .write = btrfs_file_write, 1252 .mmap = btrfs_file_mmap, 1253 .open = generic_file_open, 1254 .release = btrfs_release_file, 1255 .fsync = btrfs_sync_file, 1256 .unlocked_ioctl = btrfs_ioctl, 1257 #ifdef CONFIG_COMPAT 1258 .compat_ioctl = btrfs_ioctl, 1259 #endif 1260 }; 1261