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