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 ram_bytes = 0; 295 u64 disk_bytenr = 0; 296 u64 orig_locked_end = locked_end; 297 u8 compression; 298 u8 encryption; 299 u16 other_encoding = 0; 300 struct extent_buffer *leaf; 301 struct btrfs_file_extent_item *extent; 302 struct btrfs_path *path; 303 struct btrfs_key key; 304 struct btrfs_file_extent_item old; 305 int keep; 306 int slot; 307 int bookend; 308 int found_type = 0; 309 int found_extent; 310 int found_inline; 311 int recow; 312 int ret; 313 314 inline_limit = 0; 315 btrfs_drop_extent_cache(inode, start, end - 1, 0); 316 317 path = btrfs_alloc_path(); 318 if (!path) 319 return -ENOMEM; 320 while (1) { 321 recow = 0; 322 btrfs_release_path(root, path); 323 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, 324 search_start, -1); 325 if (ret < 0) 326 goto out; 327 if (ret > 0) { 328 if (path->slots[0] == 0) { 329 ret = 0; 330 goto out; 331 } 332 path->slots[0]--; 333 } 334 next_slot: 335 keep = 0; 336 bookend = 0; 337 found_extent = 0; 338 found_inline = 0; 339 compression = 0; 340 encryption = 0; 341 extent = NULL; 342 leaf = path->nodes[0]; 343 slot = path->slots[0]; 344 ret = 0; 345 btrfs_item_key_to_cpu(leaf, &key, slot); 346 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY && 347 key.offset >= end) { 348 goto out; 349 } 350 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY || 351 key.objectid != inode->i_ino) { 352 goto out; 353 } 354 if (recow) { 355 search_start = max(key.offset, start); 356 continue; 357 } 358 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) { 359 extent = btrfs_item_ptr(leaf, slot, 360 struct btrfs_file_extent_item); 361 found_type = btrfs_file_extent_type(leaf, extent); 362 compression = btrfs_file_extent_compression(leaf, 363 extent); 364 encryption = btrfs_file_extent_encryption(leaf, 365 extent); 366 other_encoding = btrfs_file_extent_other_encoding(leaf, 367 extent); 368 if (found_type == BTRFS_FILE_EXTENT_REG || 369 found_type == BTRFS_FILE_EXTENT_PREALLOC) { 370 extent_end = 371 btrfs_file_extent_disk_bytenr(leaf, 372 extent); 373 if (extent_end) 374 *hint_byte = extent_end; 375 376 extent_end = key.offset + 377 btrfs_file_extent_num_bytes(leaf, extent); 378 ram_bytes = btrfs_file_extent_ram_bytes(leaf, 379 extent); 380 found_extent = 1; 381 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { 382 found_inline = 1; 383 extent_end = key.offset + 384 btrfs_file_extent_inline_len(leaf, extent); 385 } 386 } else { 387 extent_end = search_start; 388 } 389 390 /* we found nothing we can drop */ 391 if ((!found_extent && !found_inline) || 392 search_start >= extent_end) { 393 int nextret; 394 u32 nritems; 395 nritems = btrfs_header_nritems(leaf); 396 if (slot >= nritems - 1) { 397 nextret = btrfs_next_leaf(root, path); 398 if (nextret) 399 goto out; 400 recow = 1; 401 } else { 402 path->slots[0]++; 403 } 404 goto next_slot; 405 } 406 407 if (end <= extent_end && start >= key.offset && found_inline) 408 *hint_byte = EXTENT_MAP_INLINE; 409 410 if (found_extent) { 411 read_extent_buffer(leaf, &old, (unsigned long)extent, 412 sizeof(old)); 413 } 414 415 if (end < extent_end && end >= key.offset) { 416 bookend = 1; 417 if (found_inline && start <= key.offset) 418 keep = 1; 419 } 420 421 if (bookend && found_extent) { 422 if (locked_end < extent_end) { 423 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 424 locked_end, extent_end - 1, 425 GFP_NOFS); 426 if (!ret) { 427 btrfs_release_path(root, path); 428 lock_extent(&BTRFS_I(inode)->io_tree, 429 locked_end, extent_end - 1, 430 GFP_NOFS); 431 locked_end = extent_end; 432 continue; 433 } 434 locked_end = extent_end; 435 } 436 disk_bytenr = le64_to_cpu(old.disk_bytenr); 437 if (disk_bytenr != 0) { 438 ret = btrfs_inc_extent_ref(trans, root, 439 disk_bytenr, 440 le64_to_cpu(old.disk_num_bytes), 0, 441 root->root_key.objectid, 442 key.objectid, key.offset - 443 le64_to_cpu(old.offset)); 444 BUG_ON(ret); 445 } 446 } 447 448 if (found_inline) { 449 u64 mask = root->sectorsize - 1; 450 search_start = (extent_end + mask) & ~mask; 451 } else 452 search_start = extent_end; 453 454 /* truncate existing extent */ 455 if (start > key.offset) { 456 u64 new_num; 457 u64 old_num; 458 keep = 1; 459 WARN_ON(start & (root->sectorsize - 1)); 460 if (found_extent) { 461 new_num = start - key.offset; 462 old_num = btrfs_file_extent_num_bytes(leaf, 463 extent); 464 *hint_byte = 465 btrfs_file_extent_disk_bytenr(leaf, 466 extent); 467 if (btrfs_file_extent_disk_bytenr(leaf, 468 extent)) { 469 inode_sub_bytes(inode, old_num - 470 new_num); 471 } 472 btrfs_set_file_extent_num_bytes(leaf, 473 extent, new_num); 474 btrfs_mark_buffer_dirty(leaf); 475 } else if (key.offset < inline_limit && 476 (end > extent_end) && 477 (inline_limit < extent_end)) { 478 u32 new_size; 479 new_size = btrfs_file_extent_calc_inline_size( 480 inline_limit - key.offset); 481 inode_sub_bytes(inode, extent_end - 482 inline_limit); 483 btrfs_set_file_extent_ram_bytes(leaf, extent, 484 new_size); 485 if (!compression && !encryption) { 486 btrfs_truncate_item(trans, root, path, 487 new_size, 1); 488 } 489 } 490 } 491 /* delete the entire extent */ 492 if (!keep) { 493 if (found_inline) 494 inode_sub_bytes(inode, extent_end - 495 key.offset); 496 ret = btrfs_del_item(trans, root, path); 497 /* TODO update progress marker and return */ 498 BUG_ON(ret); 499 extent = NULL; 500 btrfs_release_path(root, path); 501 /* the extent will be freed later */ 502 } 503 if (bookend && found_inline && start <= key.offset) { 504 u32 new_size; 505 new_size = btrfs_file_extent_calc_inline_size( 506 extent_end - end); 507 inode_sub_bytes(inode, end - key.offset); 508 btrfs_set_file_extent_ram_bytes(leaf, extent, 509 new_size); 510 if (!compression && !encryption) 511 ret = btrfs_truncate_item(trans, root, path, 512 new_size, 0); 513 BUG_ON(ret); 514 } 515 /* create bookend, splitting the extent in two */ 516 if (bookend && found_extent) { 517 struct btrfs_key ins; 518 ins.objectid = inode->i_ino; 519 ins.offset = end; 520 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY); 521 522 btrfs_release_path(root, path); 523 path->leave_spinning = 1; 524 ret = btrfs_insert_empty_item(trans, root, path, &ins, 525 sizeof(*extent)); 526 BUG_ON(ret); 527 528 leaf = path->nodes[0]; 529 extent = btrfs_item_ptr(leaf, path->slots[0], 530 struct btrfs_file_extent_item); 531 write_extent_buffer(leaf, &old, 532 (unsigned long)extent, sizeof(old)); 533 534 btrfs_set_file_extent_compression(leaf, extent, 535 compression); 536 btrfs_set_file_extent_encryption(leaf, extent, 537 encryption); 538 btrfs_set_file_extent_other_encoding(leaf, extent, 539 other_encoding); 540 btrfs_set_file_extent_offset(leaf, extent, 541 le64_to_cpu(old.offset) + end - key.offset); 542 WARN_ON(le64_to_cpu(old.num_bytes) < 543 (extent_end - end)); 544 btrfs_set_file_extent_num_bytes(leaf, extent, 545 extent_end - end); 546 547 /* 548 * set the ram bytes to the size of the full extent 549 * before splitting. This is a worst case flag, 550 * but its the best we can do because we don't know 551 * how splitting affects compression 552 */ 553 btrfs_set_file_extent_ram_bytes(leaf, extent, 554 ram_bytes); 555 btrfs_set_file_extent_type(leaf, extent, found_type); 556 557 btrfs_unlock_up_safe(path, 1); 558 btrfs_mark_buffer_dirty(path->nodes[0]); 559 btrfs_set_lock_blocking(path->nodes[0]); 560 561 path->leave_spinning = 0; 562 btrfs_release_path(root, path); 563 if (disk_bytenr != 0) 564 inode_add_bytes(inode, extent_end - end); 565 } 566 567 if (found_extent && !keep) { 568 u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr); 569 570 if (old_disk_bytenr != 0) { 571 inode_sub_bytes(inode, 572 le64_to_cpu(old.num_bytes)); 573 ret = btrfs_free_extent(trans, root, 574 old_disk_bytenr, 575 le64_to_cpu(old.disk_num_bytes), 576 0, root->root_key.objectid, 577 key.objectid, key.offset - 578 le64_to_cpu(old.offset)); 579 BUG_ON(ret); 580 *hint_byte = old_disk_bytenr; 581 } 582 } 583 584 if (search_start >= end) { 585 ret = 0; 586 goto out; 587 } 588 } 589 out: 590 btrfs_free_path(path); 591 if (locked_end > orig_locked_end) { 592 unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end, 593 locked_end - 1, GFP_NOFS); 594 } 595 return ret; 596 } 597 598 static int extent_mergeable(struct extent_buffer *leaf, int slot, 599 u64 objectid, u64 bytenr, u64 *start, u64 *end) 600 { 601 struct btrfs_file_extent_item *fi; 602 struct btrfs_key key; 603 u64 extent_end; 604 605 if (slot < 0 || slot >= btrfs_header_nritems(leaf)) 606 return 0; 607 608 btrfs_item_key_to_cpu(leaf, &key, slot); 609 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) 610 return 0; 611 612 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); 613 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || 614 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || 615 btrfs_file_extent_compression(leaf, fi) || 616 btrfs_file_extent_encryption(leaf, fi) || 617 btrfs_file_extent_other_encoding(leaf, fi)) 618 return 0; 619 620 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 621 if ((*start && *start != key.offset) || (*end && *end != extent_end)) 622 return 0; 623 624 *start = key.offset; 625 *end = extent_end; 626 return 1; 627 } 628 629 /* 630 * Mark extent in the range start - end as written. 631 * 632 * This changes extent type from 'pre-allocated' to 'regular'. If only 633 * part of extent is marked as written, the extent will be split into 634 * two or three. 635 */ 636 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, 637 struct btrfs_root *root, 638 struct inode *inode, u64 start, u64 end) 639 { 640 struct extent_buffer *leaf; 641 struct btrfs_path *path; 642 struct btrfs_file_extent_item *fi; 643 struct btrfs_key key; 644 u64 bytenr; 645 u64 num_bytes; 646 u64 extent_end; 647 u64 orig_offset; 648 u64 other_start; 649 u64 other_end; 650 u64 split = start; 651 u64 locked_end = end; 652 int extent_type; 653 int split_end = 1; 654 int ret; 655 656 btrfs_drop_extent_cache(inode, start, end - 1, 0); 657 658 path = btrfs_alloc_path(); 659 BUG_ON(!path); 660 again: 661 key.objectid = inode->i_ino; 662 key.type = BTRFS_EXTENT_DATA_KEY; 663 if (split == start) 664 key.offset = split; 665 else 666 key.offset = split - 1; 667 668 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 669 if (ret > 0 && path->slots[0] > 0) 670 path->slots[0]--; 671 672 leaf = path->nodes[0]; 673 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 674 BUG_ON(key.objectid != inode->i_ino || 675 key.type != BTRFS_EXTENT_DATA_KEY); 676 fi = btrfs_item_ptr(leaf, path->slots[0], 677 struct btrfs_file_extent_item); 678 extent_type = btrfs_file_extent_type(leaf, fi); 679 BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC); 680 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 681 BUG_ON(key.offset > start || extent_end < end); 682 683 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 684 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 685 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); 686 687 if (key.offset == start) 688 split = end; 689 690 if (key.offset == start && extent_end == end) { 691 int del_nr = 0; 692 int del_slot = 0; 693 other_start = end; 694 other_end = 0; 695 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, 696 bytenr, &other_start, &other_end)) { 697 extent_end = other_end; 698 del_slot = path->slots[0] + 1; 699 del_nr++; 700 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 701 0, root->root_key.objectid, 702 inode->i_ino, orig_offset); 703 BUG_ON(ret); 704 } 705 other_start = 0; 706 other_end = start; 707 if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino, 708 bytenr, &other_start, &other_end)) { 709 key.offset = other_start; 710 del_slot = path->slots[0]; 711 del_nr++; 712 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 713 0, root->root_key.objectid, 714 inode->i_ino, orig_offset); 715 BUG_ON(ret); 716 } 717 split_end = 0; 718 if (del_nr == 0) { 719 btrfs_set_file_extent_type(leaf, fi, 720 BTRFS_FILE_EXTENT_REG); 721 goto done; 722 } 723 724 fi = btrfs_item_ptr(leaf, del_slot - 1, 725 struct btrfs_file_extent_item); 726 btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG); 727 btrfs_set_file_extent_num_bytes(leaf, fi, 728 extent_end - key.offset); 729 btrfs_mark_buffer_dirty(leaf); 730 731 ret = btrfs_del_items(trans, root, path, del_slot, del_nr); 732 BUG_ON(ret); 733 goto release; 734 } else if (split == start) { 735 if (locked_end < extent_end) { 736 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 737 locked_end, extent_end - 1, GFP_NOFS); 738 if (!ret) { 739 btrfs_release_path(root, path); 740 lock_extent(&BTRFS_I(inode)->io_tree, 741 locked_end, extent_end - 1, GFP_NOFS); 742 locked_end = extent_end; 743 goto again; 744 } 745 locked_end = extent_end; 746 } 747 btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset); 748 } else { 749 BUG_ON(key.offset != start); 750 key.offset = split; 751 btrfs_set_file_extent_offset(leaf, fi, key.offset - 752 orig_offset); 753 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split); 754 btrfs_set_item_key_safe(trans, root, path, &key); 755 extent_end = split; 756 } 757 758 if (extent_end == end) { 759 split_end = 0; 760 extent_type = BTRFS_FILE_EXTENT_REG; 761 } 762 if (extent_end == end && split == start) { 763 other_start = end; 764 other_end = 0; 765 if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, 766 bytenr, &other_start, &other_end)) { 767 path->slots[0]++; 768 fi = btrfs_item_ptr(leaf, path->slots[0], 769 struct btrfs_file_extent_item); 770 key.offset = split; 771 btrfs_set_item_key_safe(trans, root, path, &key); 772 btrfs_set_file_extent_offset(leaf, fi, key.offset - 773 orig_offset); 774 btrfs_set_file_extent_num_bytes(leaf, fi, 775 other_end - split); 776 goto done; 777 } 778 } 779 if (extent_end == end && split == end) { 780 other_start = 0; 781 other_end = start; 782 if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino, 783 bytenr, &other_start, &other_end)) { 784 path->slots[0]--; 785 fi = btrfs_item_ptr(leaf, path->slots[0], 786 struct btrfs_file_extent_item); 787 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - 788 other_start); 789 goto done; 790 } 791 } 792 793 btrfs_mark_buffer_dirty(leaf); 794 795 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, 796 root->root_key.objectid, 797 inode->i_ino, orig_offset); 798 BUG_ON(ret); 799 btrfs_release_path(root, path); 800 801 key.offset = start; 802 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi)); 803 BUG_ON(ret); 804 805 leaf = path->nodes[0]; 806 fi = btrfs_item_ptr(leaf, path->slots[0], 807 struct btrfs_file_extent_item); 808 btrfs_set_file_extent_generation(leaf, fi, trans->transid); 809 btrfs_set_file_extent_type(leaf, fi, extent_type); 810 btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr); 811 btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes); 812 btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset); 813 btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset); 814 btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); 815 btrfs_set_file_extent_compression(leaf, fi, 0); 816 btrfs_set_file_extent_encryption(leaf, fi, 0); 817 btrfs_set_file_extent_other_encoding(leaf, fi, 0); 818 done: 819 btrfs_mark_buffer_dirty(leaf); 820 821 release: 822 btrfs_release_path(root, path); 823 if (split_end && split == start) { 824 split = end; 825 goto again; 826 } 827 if (locked_end > end) { 828 unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1, 829 GFP_NOFS); 830 } 831 btrfs_free_path(path); 832 return 0; 833 } 834 835 /* 836 * this gets pages into the page cache and locks them down, it also properly 837 * waits for data=ordered extents to finish before allowing the pages to be 838 * modified. 839 */ 840 static noinline int prepare_pages(struct btrfs_root *root, struct file *file, 841 struct page **pages, size_t num_pages, 842 loff_t pos, unsigned long first_index, 843 unsigned long last_index, size_t write_bytes) 844 { 845 int i; 846 unsigned long index = pos >> PAGE_CACHE_SHIFT; 847 struct inode *inode = fdentry(file)->d_inode; 848 int err = 0; 849 u64 start_pos; 850 u64 last_pos; 851 852 start_pos = pos & ~((u64)root->sectorsize - 1); 853 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; 854 855 if (start_pos > inode->i_size) { 856 err = btrfs_cont_expand(inode, start_pos); 857 if (err) 858 return err; 859 } 860 861 memset(pages, 0, num_pages * sizeof(struct page *)); 862 again: 863 for (i = 0; i < num_pages; i++) { 864 pages[i] = grab_cache_page(inode->i_mapping, index + i); 865 if (!pages[i]) { 866 err = -ENOMEM; 867 BUG_ON(1); 868 } 869 wait_on_page_writeback(pages[i]); 870 } 871 if (start_pos < inode->i_size) { 872 struct btrfs_ordered_extent *ordered; 873 lock_extent(&BTRFS_I(inode)->io_tree, 874 start_pos, last_pos - 1, GFP_NOFS); 875 ordered = btrfs_lookup_first_ordered_extent(inode, 876 last_pos - 1); 877 if (ordered && 878 ordered->file_offset + ordered->len > start_pos && 879 ordered->file_offset < last_pos) { 880 btrfs_put_ordered_extent(ordered); 881 unlock_extent(&BTRFS_I(inode)->io_tree, 882 start_pos, last_pos - 1, GFP_NOFS); 883 for (i = 0; i < num_pages; i++) { 884 unlock_page(pages[i]); 885 page_cache_release(pages[i]); 886 } 887 btrfs_wait_ordered_range(inode, start_pos, 888 last_pos - start_pos); 889 goto again; 890 } 891 if (ordered) 892 btrfs_put_ordered_extent(ordered); 893 894 clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos, 895 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC, 896 GFP_NOFS); 897 unlock_extent(&BTRFS_I(inode)->io_tree, 898 start_pos, last_pos - 1, GFP_NOFS); 899 } 900 for (i = 0; i < num_pages; i++) { 901 clear_page_dirty_for_io(pages[i]); 902 set_page_extent_mapped(pages[i]); 903 WARN_ON(!PageLocked(pages[i])); 904 } 905 return 0; 906 } 907 908 static ssize_t btrfs_file_write(struct file *file, const char __user *buf, 909 size_t count, loff_t *ppos) 910 { 911 loff_t pos; 912 loff_t start_pos; 913 ssize_t num_written = 0; 914 ssize_t err = 0; 915 int ret = 0; 916 struct inode *inode = fdentry(file)->d_inode; 917 struct btrfs_root *root = BTRFS_I(inode)->root; 918 struct page **pages = NULL; 919 int nrptrs; 920 struct page *pinned[2]; 921 unsigned long first_index; 922 unsigned long last_index; 923 int will_write; 924 925 will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) || 926 (file->f_flags & O_DIRECT)); 927 928 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, 929 PAGE_CACHE_SIZE / (sizeof(struct page *))); 930 pinned[0] = NULL; 931 pinned[1] = NULL; 932 933 pos = *ppos; 934 start_pos = pos; 935 936 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); 937 current->backing_dev_info = inode->i_mapping->backing_dev_info; 938 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); 939 if (err) 940 goto out_nolock; 941 if (count == 0) 942 goto out_nolock; 943 944 err = file_remove_suid(file); 945 if (err) 946 goto out_nolock; 947 file_update_time(file); 948 949 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); 950 951 mutex_lock(&inode->i_mutex); 952 BTRFS_I(inode)->sequence++; 953 first_index = pos >> PAGE_CACHE_SHIFT; 954 last_index = (pos + count) >> PAGE_CACHE_SHIFT; 955 956 /* 957 * there are lots of better ways to do this, but this code 958 * makes sure the first and last page in the file range are 959 * up to date and ready for cow 960 */ 961 if ((pos & (PAGE_CACHE_SIZE - 1))) { 962 pinned[0] = grab_cache_page(inode->i_mapping, first_index); 963 if (!PageUptodate(pinned[0])) { 964 ret = btrfs_readpage(NULL, pinned[0]); 965 BUG_ON(ret); 966 wait_on_page_locked(pinned[0]); 967 } else { 968 unlock_page(pinned[0]); 969 } 970 } 971 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { 972 pinned[1] = grab_cache_page(inode->i_mapping, last_index); 973 if (!PageUptodate(pinned[1])) { 974 ret = btrfs_readpage(NULL, pinned[1]); 975 BUG_ON(ret); 976 wait_on_page_locked(pinned[1]); 977 } else { 978 unlock_page(pinned[1]); 979 } 980 } 981 982 while (count > 0) { 983 size_t offset = pos & (PAGE_CACHE_SIZE - 1); 984 size_t write_bytes = min(count, nrptrs * 985 (size_t)PAGE_CACHE_SIZE - 986 offset); 987 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> 988 PAGE_CACHE_SHIFT; 989 990 WARN_ON(num_pages > nrptrs); 991 memset(pages, 0, sizeof(struct page *) * nrptrs); 992 993 ret = btrfs_check_data_free_space(root, inode, write_bytes); 994 if (ret) 995 goto out; 996 997 ret = prepare_pages(root, file, pages, num_pages, 998 pos, first_index, last_index, 999 write_bytes); 1000 if (ret) { 1001 btrfs_free_reserved_data_space(root, inode, 1002 write_bytes); 1003 goto out; 1004 } 1005 1006 ret = btrfs_copy_from_user(pos, num_pages, 1007 write_bytes, pages, buf); 1008 if (ret) { 1009 btrfs_free_reserved_data_space(root, inode, 1010 write_bytes); 1011 btrfs_drop_pages(pages, num_pages); 1012 goto out; 1013 } 1014 1015 ret = dirty_and_release_pages(NULL, root, file, pages, 1016 num_pages, pos, write_bytes); 1017 btrfs_drop_pages(pages, num_pages); 1018 if (ret) { 1019 btrfs_free_reserved_data_space(root, inode, 1020 write_bytes); 1021 goto out; 1022 } 1023 1024 if (will_write) { 1025 btrfs_fdatawrite_range(inode->i_mapping, pos, 1026 pos + write_bytes - 1, 1027 WB_SYNC_ALL); 1028 } else { 1029 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1030 num_pages); 1031 if (num_pages < 1032 (root->leafsize >> PAGE_CACHE_SHIFT) + 1) 1033 btrfs_btree_balance_dirty(root, 1); 1034 btrfs_throttle(root); 1035 } 1036 1037 buf += write_bytes; 1038 count -= write_bytes; 1039 pos += write_bytes; 1040 num_written += write_bytes; 1041 1042 cond_resched(); 1043 } 1044 out: 1045 mutex_unlock(&inode->i_mutex); 1046 if (ret) 1047 err = ret; 1048 1049 out_nolock: 1050 kfree(pages); 1051 if (pinned[0]) 1052 page_cache_release(pinned[0]); 1053 if (pinned[1]) 1054 page_cache_release(pinned[1]); 1055 *ppos = pos; 1056 1057 /* 1058 * we want to make sure fsync finds this change 1059 * but we haven't joined a transaction running right now. 1060 * 1061 * Later on, someone is sure to update the inode and get the 1062 * real transid recorded. 1063 * 1064 * We set last_trans now to the fs_info generation + 1, 1065 * this will either be one more than the running transaction 1066 * or the generation used for the next transaction if there isn't 1067 * one running right now. 1068 */ 1069 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1; 1070 1071 if (num_written > 0 && will_write) { 1072 struct btrfs_trans_handle *trans; 1073 1074 err = btrfs_wait_ordered_range(inode, start_pos, num_written); 1075 if (err) 1076 num_written = err; 1077 1078 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) { 1079 trans = btrfs_start_transaction(root, 1); 1080 ret = btrfs_log_dentry_safe(trans, root, 1081 file->f_dentry); 1082 if (ret == 0) { 1083 ret = btrfs_sync_log(trans, root); 1084 if (ret == 0) 1085 btrfs_end_transaction(trans, root); 1086 else 1087 btrfs_commit_transaction(trans, root); 1088 } else { 1089 btrfs_commit_transaction(trans, root); 1090 } 1091 } 1092 if (file->f_flags & O_DIRECT) { 1093 invalidate_mapping_pages(inode->i_mapping, 1094 start_pos >> PAGE_CACHE_SHIFT, 1095 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT); 1096 } 1097 } 1098 current->backing_dev_info = NULL; 1099 return num_written ? num_written : err; 1100 } 1101 1102 int btrfs_release_file(struct inode *inode, struct file *filp) 1103 { 1104 /* 1105 * ordered_data_close is set by settattr when we are about to truncate 1106 * a file from a non-zero size to a zero size. This tries to 1107 * flush down new bytes that may have been written if the 1108 * application were using truncate to replace a file in place. 1109 */ 1110 if (BTRFS_I(inode)->ordered_data_close) { 1111 BTRFS_I(inode)->ordered_data_close = 0; 1112 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode); 1113 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT) 1114 filemap_flush(inode->i_mapping); 1115 } 1116 if (filp->private_data) 1117 btrfs_ioctl_trans_end(filp); 1118 return 0; 1119 } 1120 1121 /* 1122 * fsync call for both files and directories. This logs the inode into 1123 * the tree log instead of forcing full commits whenever possible. 1124 * 1125 * It needs to call filemap_fdatawait so that all ordered extent updates are 1126 * in the metadata btree are up to date for copying to the log. 1127 * 1128 * It drops the inode mutex before doing the tree log commit. This is an 1129 * important optimization for directories because holding the mutex prevents 1130 * new operations on the dir while we write to disk. 1131 */ 1132 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync) 1133 { 1134 struct inode *inode = dentry->d_inode; 1135 struct btrfs_root *root = BTRFS_I(inode)->root; 1136 int ret = 0; 1137 struct btrfs_trans_handle *trans; 1138 1139 /* 1140 * check the transaction that last modified this inode 1141 * and see if its already been committed 1142 */ 1143 if (!BTRFS_I(inode)->last_trans) 1144 goto out; 1145 1146 mutex_lock(&root->fs_info->trans_mutex); 1147 if (BTRFS_I(inode)->last_trans <= 1148 root->fs_info->last_trans_committed) { 1149 BTRFS_I(inode)->last_trans = 0; 1150 mutex_unlock(&root->fs_info->trans_mutex); 1151 goto out; 1152 } 1153 mutex_unlock(&root->fs_info->trans_mutex); 1154 1155 root->log_batch++; 1156 filemap_fdatawrite(inode->i_mapping); 1157 btrfs_wait_ordered_range(inode, 0, (u64)-1); 1158 root->log_batch++; 1159 1160 if (datasync && !(inode->i_state & I_DIRTY_PAGES)) 1161 goto out; 1162 /* 1163 * ok we haven't committed the transaction yet, lets do a commit 1164 */ 1165 if (file && file->private_data) 1166 btrfs_ioctl_trans_end(file); 1167 1168 trans = btrfs_start_transaction(root, 1); 1169 if (!trans) { 1170 ret = -ENOMEM; 1171 goto out; 1172 } 1173 1174 ret = btrfs_log_dentry_safe(trans, root, dentry); 1175 if (ret < 0) 1176 goto out; 1177 1178 /* we've logged all the items and now have a consistent 1179 * version of the file in the log. It is possible that 1180 * someone will come in and modify the file, but that's 1181 * fine because the log is consistent on disk, and we 1182 * have references to all of the file's extents 1183 * 1184 * It is possible that someone will come in and log the 1185 * file again, but that will end up using the synchronization 1186 * inside btrfs_sync_log to keep things safe. 1187 */ 1188 mutex_unlock(&dentry->d_inode->i_mutex); 1189 1190 if (ret > 0) { 1191 ret = btrfs_commit_transaction(trans, root); 1192 } else { 1193 ret = btrfs_sync_log(trans, root); 1194 if (ret == 0) 1195 ret = btrfs_end_transaction(trans, root); 1196 else 1197 ret = btrfs_commit_transaction(trans, root); 1198 } 1199 mutex_lock(&dentry->d_inode->i_mutex); 1200 out: 1201 return ret > 0 ? EIO : ret; 1202 } 1203 1204 static struct vm_operations_struct btrfs_file_vm_ops = { 1205 .fault = filemap_fault, 1206 .page_mkwrite = btrfs_page_mkwrite, 1207 }; 1208 1209 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) 1210 { 1211 vma->vm_ops = &btrfs_file_vm_ops; 1212 file_accessed(filp); 1213 return 0; 1214 } 1215 1216 struct file_operations btrfs_file_operations = { 1217 .llseek = generic_file_llseek, 1218 .read = do_sync_read, 1219 .aio_read = generic_file_aio_read, 1220 .splice_read = generic_file_splice_read, 1221 .write = btrfs_file_write, 1222 .mmap = btrfs_file_mmap, 1223 .open = generic_file_open, 1224 .release = btrfs_release_file, 1225 .fsync = btrfs_sync_file, 1226 .unlocked_ioctl = btrfs_ioctl, 1227 #ifdef CONFIG_COMPAT 1228 .compat_ioctl = btrfs_ioctl, 1229 #endif 1230 }; 1231