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/backing-dev.h> 26 #include <linux/mpage.h> 27 #include <linux/swap.h> 28 #include <linux/writeback.h> 29 #include <linux/statfs.h> 30 #include <linux/compat.h> 31 #include <linux/slab.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 u64 num_bytes; 117 u64 start_pos; 118 u64 end_of_last_block; 119 u64 end_pos = pos + write_bytes; 120 loff_t isize = i_size_read(inode); 121 122 start_pos = pos & ~((u64)root->sectorsize - 1); 123 num_bytes = (write_bytes + pos - start_pos + 124 root->sectorsize - 1) & ~((u64)root->sectorsize - 1); 125 126 end_of_last_block = start_pos + num_bytes - 1; 127 err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block, 128 NULL); 129 if (err) 130 return err; 131 132 for (i = 0; i < num_pages; i++) { 133 struct page *p = pages[i]; 134 SetPageUptodate(p); 135 ClearPageChecked(p); 136 set_page_dirty(p); 137 } 138 if (end_pos > isize) { 139 i_size_write(inode, end_pos); 140 /* we've only changed i_size in ram, and we haven't updated 141 * the disk i_size. There is no need to log the inode 142 * at this time. 143 */ 144 } 145 return err; 146 } 147 148 /* 149 * this drops all the extents in the cache that intersect the range 150 * [start, end]. Existing extents are split as required. 151 */ 152 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, 153 int skip_pinned) 154 { 155 struct extent_map *em; 156 struct extent_map *split = NULL; 157 struct extent_map *split2 = NULL; 158 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 159 u64 len = end - start + 1; 160 int ret; 161 int testend = 1; 162 unsigned long flags; 163 int compressed = 0; 164 165 WARN_ON(end < start); 166 if (end == (u64)-1) { 167 len = (u64)-1; 168 testend = 0; 169 } 170 while (1) { 171 if (!split) 172 split = alloc_extent_map(GFP_NOFS); 173 if (!split2) 174 split2 = alloc_extent_map(GFP_NOFS); 175 176 write_lock(&em_tree->lock); 177 em = lookup_extent_mapping(em_tree, start, len); 178 if (!em) { 179 write_unlock(&em_tree->lock); 180 break; 181 } 182 flags = em->flags; 183 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) { 184 if (testend && em->start + em->len >= start + len) { 185 free_extent_map(em); 186 write_unlock(&em_tree->lock); 187 break; 188 } 189 start = em->start + em->len; 190 if (testend) 191 len = start + len - (em->start + em->len); 192 free_extent_map(em); 193 write_unlock(&em_tree->lock); 194 continue; 195 } 196 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); 197 clear_bit(EXTENT_FLAG_PINNED, &em->flags); 198 remove_extent_mapping(em_tree, em); 199 200 if (em->block_start < EXTENT_MAP_LAST_BYTE && 201 em->start < start) { 202 split->start = em->start; 203 split->len = start - em->start; 204 split->orig_start = em->orig_start; 205 split->block_start = em->block_start; 206 207 if (compressed) 208 split->block_len = em->block_len; 209 else 210 split->block_len = split->len; 211 212 split->bdev = em->bdev; 213 split->flags = flags; 214 ret = add_extent_mapping(em_tree, split); 215 BUG_ON(ret); 216 free_extent_map(split); 217 split = split2; 218 split2 = NULL; 219 } 220 if (em->block_start < EXTENT_MAP_LAST_BYTE && 221 testend && em->start + em->len > start + len) { 222 u64 diff = start + len - em->start; 223 224 split->start = start + len; 225 split->len = em->start + em->len - (start + len); 226 split->bdev = em->bdev; 227 split->flags = flags; 228 229 if (compressed) { 230 split->block_len = em->block_len; 231 split->block_start = em->block_start; 232 split->orig_start = em->orig_start; 233 } else { 234 split->block_len = split->len; 235 split->block_start = em->block_start + diff; 236 split->orig_start = split->start; 237 } 238 239 ret = add_extent_mapping(em_tree, split); 240 BUG_ON(ret); 241 free_extent_map(split); 242 split = NULL; 243 } 244 write_unlock(&em_tree->lock); 245 246 /* once for us */ 247 free_extent_map(em); 248 /* once for the tree*/ 249 free_extent_map(em); 250 } 251 if (split) 252 free_extent_map(split); 253 if (split2) 254 free_extent_map(split2); 255 return 0; 256 } 257 258 /* 259 * this is very complex, but the basic idea is to drop all extents 260 * in the range start - end. hint_block is filled in with a block number 261 * that would be a good hint to the block allocator for this file. 262 * 263 * If an extent intersects the range but is not entirely inside the range 264 * it is either truncated or split. Anything entirely inside the range 265 * is deleted from the tree. 266 */ 267 int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode, 268 u64 start, u64 end, u64 *hint_byte, int drop_cache) 269 { 270 struct btrfs_root *root = BTRFS_I(inode)->root; 271 struct extent_buffer *leaf; 272 struct btrfs_file_extent_item *fi; 273 struct btrfs_path *path; 274 struct btrfs_key key; 275 struct btrfs_key new_key; 276 u64 search_start = start; 277 u64 disk_bytenr = 0; 278 u64 num_bytes = 0; 279 u64 extent_offset = 0; 280 u64 extent_end = 0; 281 int del_nr = 0; 282 int del_slot = 0; 283 int extent_type; 284 int recow; 285 int ret; 286 287 if (drop_cache) 288 btrfs_drop_extent_cache(inode, start, end - 1, 0); 289 290 path = btrfs_alloc_path(); 291 if (!path) 292 return -ENOMEM; 293 294 while (1) { 295 recow = 0; 296 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, 297 search_start, -1); 298 if (ret < 0) 299 break; 300 if (ret > 0 && path->slots[0] > 0 && search_start == start) { 301 leaf = path->nodes[0]; 302 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); 303 if (key.objectid == inode->i_ino && 304 key.type == BTRFS_EXTENT_DATA_KEY) 305 path->slots[0]--; 306 } 307 ret = 0; 308 next_slot: 309 leaf = path->nodes[0]; 310 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 311 BUG_ON(del_nr > 0); 312 ret = btrfs_next_leaf(root, path); 313 if (ret < 0) 314 break; 315 if (ret > 0) { 316 ret = 0; 317 break; 318 } 319 leaf = path->nodes[0]; 320 recow = 1; 321 } 322 323 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 324 if (key.objectid > inode->i_ino || 325 key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) 326 break; 327 328 fi = btrfs_item_ptr(leaf, path->slots[0], 329 struct btrfs_file_extent_item); 330 extent_type = btrfs_file_extent_type(leaf, fi); 331 332 if (extent_type == BTRFS_FILE_EXTENT_REG || 333 extent_type == BTRFS_FILE_EXTENT_PREALLOC) { 334 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 335 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 336 extent_offset = btrfs_file_extent_offset(leaf, fi); 337 extent_end = key.offset + 338 btrfs_file_extent_num_bytes(leaf, fi); 339 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { 340 extent_end = key.offset + 341 btrfs_file_extent_inline_len(leaf, fi); 342 } else { 343 WARN_ON(1); 344 extent_end = search_start; 345 } 346 347 if (extent_end <= search_start) { 348 path->slots[0]++; 349 goto next_slot; 350 } 351 352 search_start = max(key.offset, start); 353 if (recow) { 354 btrfs_release_path(root, path); 355 continue; 356 } 357 358 /* 359 * | - range to drop - | 360 * | -------- extent -------- | 361 */ 362 if (start > key.offset && end < extent_end) { 363 BUG_ON(del_nr > 0); 364 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); 365 366 memcpy(&new_key, &key, sizeof(new_key)); 367 new_key.offset = start; 368 ret = btrfs_duplicate_item(trans, root, path, 369 &new_key); 370 if (ret == -EAGAIN) { 371 btrfs_release_path(root, path); 372 continue; 373 } 374 if (ret < 0) 375 break; 376 377 leaf = path->nodes[0]; 378 fi = btrfs_item_ptr(leaf, path->slots[0] - 1, 379 struct btrfs_file_extent_item); 380 btrfs_set_file_extent_num_bytes(leaf, fi, 381 start - key.offset); 382 383 fi = btrfs_item_ptr(leaf, path->slots[0], 384 struct btrfs_file_extent_item); 385 386 extent_offset += start - key.offset; 387 btrfs_set_file_extent_offset(leaf, fi, extent_offset); 388 btrfs_set_file_extent_num_bytes(leaf, fi, 389 extent_end - start); 390 btrfs_mark_buffer_dirty(leaf); 391 392 if (disk_bytenr > 0) { 393 ret = btrfs_inc_extent_ref(trans, root, 394 disk_bytenr, num_bytes, 0, 395 root->root_key.objectid, 396 new_key.objectid, 397 start - extent_offset); 398 BUG_ON(ret); 399 *hint_byte = disk_bytenr; 400 } 401 key.offset = start; 402 } 403 /* 404 * | ---- range to drop ----- | 405 * | -------- extent -------- | 406 */ 407 if (start <= key.offset && end < extent_end) { 408 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); 409 410 memcpy(&new_key, &key, sizeof(new_key)); 411 new_key.offset = end; 412 btrfs_set_item_key_safe(trans, root, path, &new_key); 413 414 extent_offset += end - key.offset; 415 btrfs_set_file_extent_offset(leaf, fi, extent_offset); 416 btrfs_set_file_extent_num_bytes(leaf, fi, 417 extent_end - end); 418 btrfs_mark_buffer_dirty(leaf); 419 if (disk_bytenr > 0) { 420 inode_sub_bytes(inode, end - key.offset); 421 *hint_byte = disk_bytenr; 422 } 423 break; 424 } 425 426 search_start = extent_end; 427 /* 428 * | ---- range to drop ----- | 429 * | -------- extent -------- | 430 */ 431 if (start > key.offset && end >= extent_end) { 432 BUG_ON(del_nr > 0); 433 BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE); 434 435 btrfs_set_file_extent_num_bytes(leaf, fi, 436 start - key.offset); 437 btrfs_mark_buffer_dirty(leaf); 438 if (disk_bytenr > 0) { 439 inode_sub_bytes(inode, extent_end - start); 440 *hint_byte = disk_bytenr; 441 } 442 if (end == extent_end) 443 break; 444 445 path->slots[0]++; 446 goto next_slot; 447 } 448 449 /* 450 * | ---- range to drop ----- | 451 * | ------ extent ------ | 452 */ 453 if (start <= key.offset && end >= extent_end) { 454 if (del_nr == 0) { 455 del_slot = path->slots[0]; 456 del_nr = 1; 457 } else { 458 BUG_ON(del_slot + del_nr != path->slots[0]); 459 del_nr++; 460 } 461 462 if (extent_type == BTRFS_FILE_EXTENT_INLINE) { 463 inode_sub_bytes(inode, 464 extent_end - key.offset); 465 extent_end = ALIGN(extent_end, 466 root->sectorsize); 467 } else if (disk_bytenr > 0) { 468 ret = btrfs_free_extent(trans, root, 469 disk_bytenr, num_bytes, 0, 470 root->root_key.objectid, 471 key.objectid, key.offset - 472 extent_offset); 473 BUG_ON(ret); 474 inode_sub_bytes(inode, 475 extent_end - key.offset); 476 *hint_byte = disk_bytenr; 477 } 478 479 if (end == extent_end) 480 break; 481 482 if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) { 483 path->slots[0]++; 484 goto next_slot; 485 } 486 487 ret = btrfs_del_items(trans, root, path, del_slot, 488 del_nr); 489 BUG_ON(ret); 490 491 del_nr = 0; 492 del_slot = 0; 493 494 btrfs_release_path(root, path); 495 continue; 496 } 497 498 BUG_ON(1); 499 } 500 501 if (del_nr > 0) { 502 ret = btrfs_del_items(trans, root, path, del_slot, del_nr); 503 BUG_ON(ret); 504 } 505 506 btrfs_free_path(path); 507 return ret; 508 } 509 510 static int extent_mergeable(struct extent_buffer *leaf, int slot, 511 u64 objectid, u64 bytenr, u64 orig_offset, 512 u64 *start, u64 *end) 513 { 514 struct btrfs_file_extent_item *fi; 515 struct btrfs_key key; 516 u64 extent_end; 517 518 if (slot < 0 || slot >= btrfs_header_nritems(leaf)) 519 return 0; 520 521 btrfs_item_key_to_cpu(leaf, &key, slot); 522 if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) 523 return 0; 524 525 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); 526 if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || 527 btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || 528 btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset || 529 btrfs_file_extent_compression(leaf, fi) || 530 btrfs_file_extent_encryption(leaf, fi) || 531 btrfs_file_extent_other_encoding(leaf, fi)) 532 return 0; 533 534 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 535 if ((*start && *start != key.offset) || (*end && *end != extent_end)) 536 return 0; 537 538 *start = key.offset; 539 *end = extent_end; 540 return 1; 541 } 542 543 /* 544 * Mark extent in the range start - end as written. 545 * 546 * This changes extent type from 'pre-allocated' to 'regular'. If only 547 * part of extent is marked as written, the extent will be split into 548 * two or three. 549 */ 550 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, 551 struct inode *inode, u64 start, u64 end) 552 { 553 struct btrfs_root *root = BTRFS_I(inode)->root; 554 struct extent_buffer *leaf; 555 struct btrfs_path *path; 556 struct btrfs_file_extent_item *fi; 557 struct btrfs_key key; 558 struct btrfs_key new_key; 559 u64 bytenr; 560 u64 num_bytes; 561 u64 extent_end; 562 u64 orig_offset; 563 u64 other_start; 564 u64 other_end; 565 u64 split; 566 int del_nr = 0; 567 int del_slot = 0; 568 int recow; 569 int ret; 570 571 btrfs_drop_extent_cache(inode, start, end - 1, 0); 572 573 path = btrfs_alloc_path(); 574 BUG_ON(!path); 575 again: 576 recow = 0; 577 split = start; 578 key.objectid = inode->i_ino; 579 key.type = BTRFS_EXTENT_DATA_KEY; 580 key.offset = split; 581 582 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 583 if (ret > 0 && path->slots[0] > 0) 584 path->slots[0]--; 585 586 leaf = path->nodes[0]; 587 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 588 BUG_ON(key.objectid != inode->i_ino || 589 key.type != BTRFS_EXTENT_DATA_KEY); 590 fi = btrfs_item_ptr(leaf, path->slots[0], 591 struct btrfs_file_extent_item); 592 BUG_ON(btrfs_file_extent_type(leaf, fi) != 593 BTRFS_FILE_EXTENT_PREALLOC); 594 extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); 595 BUG_ON(key.offset > start || extent_end < end); 596 597 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 598 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 599 orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); 600 memcpy(&new_key, &key, sizeof(new_key)); 601 602 if (start == key.offset && end < extent_end) { 603 other_start = 0; 604 other_end = start; 605 if (extent_mergeable(leaf, path->slots[0] - 1, 606 inode->i_ino, bytenr, orig_offset, 607 &other_start, &other_end)) { 608 new_key.offset = end; 609 btrfs_set_item_key_safe(trans, root, path, &new_key); 610 fi = btrfs_item_ptr(leaf, path->slots[0], 611 struct btrfs_file_extent_item); 612 btrfs_set_file_extent_num_bytes(leaf, fi, 613 extent_end - end); 614 btrfs_set_file_extent_offset(leaf, fi, 615 end - orig_offset); 616 fi = btrfs_item_ptr(leaf, path->slots[0] - 1, 617 struct btrfs_file_extent_item); 618 btrfs_set_file_extent_num_bytes(leaf, fi, 619 end - other_start); 620 btrfs_mark_buffer_dirty(leaf); 621 goto out; 622 } 623 } 624 625 if (start > key.offset && end == extent_end) { 626 other_start = end; 627 other_end = 0; 628 if (extent_mergeable(leaf, path->slots[0] + 1, 629 inode->i_ino, bytenr, orig_offset, 630 &other_start, &other_end)) { 631 fi = btrfs_item_ptr(leaf, path->slots[0], 632 struct btrfs_file_extent_item); 633 btrfs_set_file_extent_num_bytes(leaf, fi, 634 start - key.offset); 635 path->slots[0]++; 636 new_key.offset = start; 637 btrfs_set_item_key_safe(trans, root, path, &new_key); 638 639 fi = btrfs_item_ptr(leaf, path->slots[0], 640 struct btrfs_file_extent_item); 641 btrfs_set_file_extent_num_bytes(leaf, fi, 642 other_end - start); 643 btrfs_set_file_extent_offset(leaf, fi, 644 start - orig_offset); 645 btrfs_mark_buffer_dirty(leaf); 646 goto out; 647 } 648 } 649 650 while (start > key.offset || end < extent_end) { 651 if (key.offset == start) 652 split = end; 653 654 new_key.offset = split; 655 ret = btrfs_duplicate_item(trans, root, path, &new_key); 656 if (ret == -EAGAIN) { 657 btrfs_release_path(root, path); 658 goto again; 659 } 660 BUG_ON(ret < 0); 661 662 leaf = path->nodes[0]; 663 fi = btrfs_item_ptr(leaf, path->slots[0] - 1, 664 struct btrfs_file_extent_item); 665 btrfs_set_file_extent_num_bytes(leaf, fi, 666 split - key.offset); 667 668 fi = btrfs_item_ptr(leaf, path->slots[0], 669 struct btrfs_file_extent_item); 670 671 btrfs_set_file_extent_offset(leaf, fi, split - orig_offset); 672 btrfs_set_file_extent_num_bytes(leaf, fi, 673 extent_end - split); 674 btrfs_mark_buffer_dirty(leaf); 675 676 ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0, 677 root->root_key.objectid, 678 inode->i_ino, orig_offset); 679 BUG_ON(ret); 680 681 if (split == start) { 682 key.offset = start; 683 } else { 684 BUG_ON(start != key.offset); 685 path->slots[0]--; 686 extent_end = end; 687 } 688 recow = 1; 689 } 690 691 other_start = end; 692 other_end = 0; 693 if (extent_mergeable(leaf, path->slots[0] + 1, 694 inode->i_ino, bytenr, orig_offset, 695 &other_start, &other_end)) { 696 if (recow) { 697 btrfs_release_path(root, path); 698 goto again; 699 } 700 extent_end = other_end; 701 del_slot = path->slots[0] + 1; 702 del_nr++; 703 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 704 0, root->root_key.objectid, 705 inode->i_ino, orig_offset); 706 BUG_ON(ret); 707 } 708 other_start = 0; 709 other_end = start; 710 if (extent_mergeable(leaf, path->slots[0] - 1, 711 inode->i_ino, bytenr, orig_offset, 712 &other_start, &other_end)) { 713 if (recow) { 714 btrfs_release_path(root, path); 715 goto again; 716 } 717 key.offset = other_start; 718 del_slot = path->slots[0]; 719 del_nr++; 720 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 721 0, root->root_key.objectid, 722 inode->i_ino, orig_offset); 723 BUG_ON(ret); 724 } 725 if (del_nr == 0) { 726 fi = btrfs_item_ptr(leaf, path->slots[0], 727 struct btrfs_file_extent_item); 728 btrfs_set_file_extent_type(leaf, fi, 729 BTRFS_FILE_EXTENT_REG); 730 btrfs_mark_buffer_dirty(leaf); 731 } else { 732 fi = btrfs_item_ptr(leaf, del_slot - 1, 733 struct btrfs_file_extent_item); 734 btrfs_set_file_extent_type(leaf, fi, 735 BTRFS_FILE_EXTENT_REG); 736 btrfs_set_file_extent_num_bytes(leaf, fi, 737 extent_end - key.offset); 738 btrfs_mark_buffer_dirty(leaf); 739 740 ret = btrfs_del_items(trans, root, path, del_slot, del_nr); 741 BUG_ON(ret); 742 } 743 out: 744 btrfs_free_path(path); 745 return 0; 746 } 747 748 /* 749 * this gets pages into the page cache and locks them down, it also properly 750 * waits for data=ordered extents to finish before allowing the pages to be 751 * modified. 752 */ 753 static noinline int prepare_pages(struct btrfs_root *root, struct file *file, 754 struct page **pages, size_t num_pages, 755 loff_t pos, unsigned long first_index, 756 unsigned long last_index, size_t write_bytes) 757 { 758 struct extent_state *cached_state = NULL; 759 int i; 760 unsigned long index = pos >> PAGE_CACHE_SHIFT; 761 struct inode *inode = fdentry(file)->d_inode; 762 int err = 0; 763 u64 start_pos; 764 u64 last_pos; 765 766 start_pos = pos & ~((u64)root->sectorsize - 1); 767 last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; 768 769 if (start_pos > inode->i_size) { 770 err = btrfs_cont_expand(inode, start_pos); 771 if (err) 772 return err; 773 } 774 775 memset(pages, 0, num_pages * sizeof(struct page *)); 776 again: 777 for (i = 0; i < num_pages; i++) { 778 pages[i] = grab_cache_page(inode->i_mapping, index + i); 779 if (!pages[i]) { 780 err = -ENOMEM; 781 BUG_ON(1); 782 } 783 wait_on_page_writeback(pages[i]); 784 } 785 if (start_pos < inode->i_size) { 786 struct btrfs_ordered_extent *ordered; 787 lock_extent_bits(&BTRFS_I(inode)->io_tree, 788 start_pos, last_pos - 1, 0, &cached_state, 789 GFP_NOFS); 790 ordered = btrfs_lookup_first_ordered_extent(inode, 791 last_pos - 1); 792 if (ordered && 793 ordered->file_offset + ordered->len > start_pos && 794 ordered->file_offset < last_pos) { 795 btrfs_put_ordered_extent(ordered); 796 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 797 start_pos, last_pos - 1, 798 &cached_state, GFP_NOFS); 799 for (i = 0; i < num_pages; i++) { 800 unlock_page(pages[i]); 801 page_cache_release(pages[i]); 802 } 803 btrfs_wait_ordered_range(inode, start_pos, 804 last_pos - start_pos); 805 goto again; 806 } 807 if (ordered) 808 btrfs_put_ordered_extent(ordered); 809 810 clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, 811 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC | 812 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state, 813 GFP_NOFS); 814 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 815 start_pos, last_pos - 1, &cached_state, 816 GFP_NOFS); 817 } 818 for (i = 0; i < num_pages; i++) { 819 clear_page_dirty_for_io(pages[i]); 820 set_page_extent_mapped(pages[i]); 821 WARN_ON(!PageLocked(pages[i])); 822 } 823 return 0; 824 } 825 826 static ssize_t btrfs_file_write(struct file *file, const char __user *buf, 827 size_t count, loff_t *ppos) 828 { 829 loff_t pos; 830 loff_t start_pos; 831 ssize_t num_written = 0; 832 ssize_t err = 0; 833 int ret = 0; 834 struct inode *inode = fdentry(file)->d_inode; 835 struct btrfs_root *root = BTRFS_I(inode)->root; 836 struct page **pages = NULL; 837 int nrptrs; 838 struct page *pinned[2]; 839 unsigned long first_index; 840 unsigned long last_index; 841 int will_write; 842 843 will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) || 844 (file->f_flags & O_DIRECT)); 845 846 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, 847 PAGE_CACHE_SIZE / (sizeof(struct page *))); 848 pinned[0] = NULL; 849 pinned[1] = NULL; 850 851 pos = *ppos; 852 start_pos = pos; 853 854 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); 855 856 /* do the reserve before the mutex lock in case we have to do some 857 * flushing. We wouldn't deadlock, but this is more polite. 858 */ 859 err = btrfs_reserve_metadata_for_delalloc(root, inode, 1); 860 if (err) 861 goto out_nolock; 862 863 mutex_lock(&inode->i_mutex); 864 865 current->backing_dev_info = inode->i_mapping->backing_dev_info; 866 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); 867 if (err) 868 goto out; 869 870 if (count == 0) 871 goto out; 872 873 err = file_remove_suid(file); 874 if (err) 875 goto out; 876 877 file_update_time(file); 878 879 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); 880 881 /* generic_write_checks can change our pos */ 882 start_pos = pos; 883 884 BTRFS_I(inode)->sequence++; 885 first_index = pos >> PAGE_CACHE_SHIFT; 886 last_index = (pos + count) >> PAGE_CACHE_SHIFT; 887 888 /* 889 * there are lots of better ways to do this, but this code 890 * makes sure the first and last page in the file range are 891 * up to date and ready for cow 892 */ 893 if ((pos & (PAGE_CACHE_SIZE - 1))) { 894 pinned[0] = grab_cache_page(inode->i_mapping, first_index); 895 if (!PageUptodate(pinned[0])) { 896 ret = btrfs_readpage(NULL, pinned[0]); 897 BUG_ON(ret); 898 wait_on_page_locked(pinned[0]); 899 } else { 900 unlock_page(pinned[0]); 901 } 902 } 903 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { 904 pinned[1] = grab_cache_page(inode->i_mapping, last_index); 905 if (!PageUptodate(pinned[1])) { 906 ret = btrfs_readpage(NULL, pinned[1]); 907 BUG_ON(ret); 908 wait_on_page_locked(pinned[1]); 909 } else { 910 unlock_page(pinned[1]); 911 } 912 } 913 914 while (count > 0) { 915 size_t offset = pos & (PAGE_CACHE_SIZE - 1); 916 size_t write_bytes = min(count, nrptrs * 917 (size_t)PAGE_CACHE_SIZE - 918 offset); 919 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> 920 PAGE_CACHE_SHIFT; 921 922 WARN_ON(num_pages > nrptrs); 923 memset(pages, 0, sizeof(struct page *) * nrptrs); 924 925 ret = btrfs_check_data_free_space(root, inode, write_bytes); 926 if (ret) 927 goto out; 928 929 ret = prepare_pages(root, file, pages, num_pages, 930 pos, first_index, last_index, 931 write_bytes); 932 if (ret) { 933 btrfs_free_reserved_data_space(root, inode, 934 write_bytes); 935 goto out; 936 } 937 938 ret = btrfs_copy_from_user(pos, num_pages, 939 write_bytes, pages, buf); 940 if (ret) { 941 btrfs_free_reserved_data_space(root, inode, 942 write_bytes); 943 btrfs_drop_pages(pages, num_pages); 944 goto out; 945 } 946 947 ret = dirty_and_release_pages(NULL, root, file, pages, 948 num_pages, pos, write_bytes); 949 btrfs_drop_pages(pages, num_pages); 950 if (ret) { 951 btrfs_free_reserved_data_space(root, inode, 952 write_bytes); 953 goto out; 954 } 955 956 if (will_write) { 957 filemap_fdatawrite_range(inode->i_mapping, pos, 958 pos + write_bytes - 1); 959 } else { 960 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 961 num_pages); 962 if (num_pages < 963 (root->leafsize >> PAGE_CACHE_SHIFT) + 1) 964 btrfs_btree_balance_dirty(root, 1); 965 btrfs_throttle(root); 966 } 967 968 buf += write_bytes; 969 count -= write_bytes; 970 pos += write_bytes; 971 num_written += write_bytes; 972 973 cond_resched(); 974 } 975 out: 976 mutex_unlock(&inode->i_mutex); 977 if (ret) 978 err = ret; 979 btrfs_unreserve_metadata_for_delalloc(root, inode, 1); 980 981 out_nolock: 982 kfree(pages); 983 if (pinned[0]) 984 page_cache_release(pinned[0]); 985 if (pinned[1]) 986 page_cache_release(pinned[1]); 987 *ppos = pos; 988 989 /* 990 * we want to make sure fsync finds this change 991 * but we haven't joined a transaction running right now. 992 * 993 * Later on, someone is sure to update the inode and get the 994 * real transid recorded. 995 * 996 * We set last_trans now to the fs_info generation + 1, 997 * this will either be one more than the running transaction 998 * or the generation used for the next transaction if there isn't 999 * one running right now. 1000 */ 1001 BTRFS_I(inode)->last_trans = root->fs_info->generation + 1; 1002 1003 if (num_written > 0 && will_write) { 1004 struct btrfs_trans_handle *trans; 1005 1006 err = btrfs_wait_ordered_range(inode, start_pos, num_written); 1007 if (err) 1008 num_written = err; 1009 1010 if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) { 1011 trans = btrfs_start_transaction(root, 1); 1012 ret = btrfs_log_dentry_safe(trans, root, 1013 file->f_dentry); 1014 if (ret == 0) { 1015 ret = btrfs_sync_log(trans, root); 1016 if (ret == 0) 1017 btrfs_end_transaction(trans, root); 1018 else 1019 btrfs_commit_transaction(trans, root); 1020 } else if (ret != BTRFS_NO_LOG_SYNC) { 1021 btrfs_commit_transaction(trans, root); 1022 } else { 1023 btrfs_end_transaction(trans, root); 1024 } 1025 } 1026 if (file->f_flags & O_DIRECT) { 1027 invalidate_mapping_pages(inode->i_mapping, 1028 start_pos >> PAGE_CACHE_SHIFT, 1029 (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT); 1030 } 1031 } 1032 current->backing_dev_info = NULL; 1033 return num_written ? num_written : err; 1034 } 1035 1036 int btrfs_release_file(struct inode *inode, struct file *filp) 1037 { 1038 /* 1039 * ordered_data_close is set by settattr when we are about to truncate 1040 * a file from a non-zero size to a zero size. This tries to 1041 * flush down new bytes that may have been written if the 1042 * application were using truncate to replace a file in place. 1043 */ 1044 if (BTRFS_I(inode)->ordered_data_close) { 1045 BTRFS_I(inode)->ordered_data_close = 0; 1046 btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode); 1047 if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT) 1048 filemap_flush(inode->i_mapping); 1049 } 1050 if (filp->private_data) 1051 btrfs_ioctl_trans_end(filp); 1052 return 0; 1053 } 1054 1055 /* 1056 * fsync call for both files and directories. This logs the inode into 1057 * the tree log instead of forcing full commits whenever possible. 1058 * 1059 * It needs to call filemap_fdatawait so that all ordered extent updates are 1060 * in the metadata btree are up to date for copying to the log. 1061 * 1062 * It drops the inode mutex before doing the tree log commit. This is an 1063 * important optimization for directories because holding the mutex prevents 1064 * new operations on the dir while we write to disk. 1065 */ 1066 int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync) 1067 { 1068 struct inode *inode = dentry->d_inode; 1069 struct btrfs_root *root = BTRFS_I(inode)->root; 1070 int ret = 0; 1071 struct btrfs_trans_handle *trans; 1072 1073 1074 /* we wait first, since the writeback may change the inode */ 1075 root->log_batch++; 1076 /* the VFS called filemap_fdatawrite for us */ 1077 btrfs_wait_ordered_range(inode, 0, (u64)-1); 1078 root->log_batch++; 1079 1080 /* 1081 * check the transaction that last modified this inode 1082 * and see if its already been committed 1083 */ 1084 if (!BTRFS_I(inode)->last_trans) 1085 goto out; 1086 1087 /* 1088 * if the last transaction that changed this file was before 1089 * the current transaction, we can bail out now without any 1090 * syncing 1091 */ 1092 mutex_lock(&root->fs_info->trans_mutex); 1093 if (BTRFS_I(inode)->last_trans <= 1094 root->fs_info->last_trans_committed) { 1095 BTRFS_I(inode)->last_trans = 0; 1096 mutex_unlock(&root->fs_info->trans_mutex); 1097 goto out; 1098 } 1099 mutex_unlock(&root->fs_info->trans_mutex); 1100 1101 /* 1102 * ok we haven't committed the transaction yet, lets do a commit 1103 */ 1104 if (file && file->private_data) 1105 btrfs_ioctl_trans_end(file); 1106 1107 trans = btrfs_start_transaction(root, 1); 1108 if (!trans) { 1109 ret = -ENOMEM; 1110 goto out; 1111 } 1112 1113 ret = btrfs_log_dentry_safe(trans, root, dentry); 1114 if (ret < 0) 1115 goto out; 1116 1117 /* we've logged all the items and now have a consistent 1118 * version of the file in the log. It is possible that 1119 * someone will come in and modify the file, but that's 1120 * fine because the log is consistent on disk, and we 1121 * have references to all of the file's extents 1122 * 1123 * It is possible that someone will come in and log the 1124 * file again, but that will end up using the synchronization 1125 * inside btrfs_sync_log to keep things safe. 1126 */ 1127 mutex_unlock(&dentry->d_inode->i_mutex); 1128 1129 if (ret != BTRFS_NO_LOG_SYNC) { 1130 if (ret > 0) { 1131 ret = btrfs_commit_transaction(trans, root); 1132 } else { 1133 ret = btrfs_sync_log(trans, root); 1134 if (ret == 0) 1135 ret = btrfs_end_transaction(trans, root); 1136 else 1137 ret = btrfs_commit_transaction(trans, root); 1138 } 1139 } else { 1140 ret = btrfs_end_transaction(trans, root); 1141 } 1142 mutex_lock(&dentry->d_inode->i_mutex); 1143 out: 1144 return ret > 0 ? -EIO : ret; 1145 } 1146 1147 static const struct vm_operations_struct btrfs_file_vm_ops = { 1148 .fault = filemap_fault, 1149 .page_mkwrite = btrfs_page_mkwrite, 1150 }; 1151 1152 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) 1153 { 1154 vma->vm_ops = &btrfs_file_vm_ops; 1155 file_accessed(filp); 1156 return 0; 1157 } 1158 1159 const struct file_operations btrfs_file_operations = { 1160 .llseek = generic_file_llseek, 1161 .read = do_sync_read, 1162 .aio_read = generic_file_aio_read, 1163 .splice_read = generic_file_splice_read, 1164 .write = btrfs_file_write, 1165 .mmap = btrfs_file_mmap, 1166 .open = generic_file_open, 1167 .release = btrfs_release_file, 1168 .fsync = btrfs_sync_file, 1169 .unlocked_ioctl = btrfs_ioctl, 1170 #ifdef CONFIG_COMPAT 1171 .compat_ioctl = btrfs_ioctl, 1172 #endif 1173 }; 1174