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 <linux/version.h> 33 #include "ctree.h" 34 #include "disk-io.h" 35 #include "transaction.h" 36 #include "btrfs_inode.h" 37 #include "ioctl.h" 38 #include "print-tree.h" 39 40 41 static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes, 42 struct page **prepared_pages, 43 const char __user * buf) 44 { 45 long page_fault = 0; 46 int i; 47 int offset = pos & (PAGE_CACHE_SIZE - 1); 48 49 for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) { 50 size_t count = min_t(size_t, 51 PAGE_CACHE_SIZE - offset, write_bytes); 52 struct page *page = prepared_pages[i]; 53 fault_in_pages_readable(buf, count); 54 55 /* Copy data from userspace to the current page */ 56 kmap(page); 57 page_fault = __copy_from_user(page_address(page) + offset, 58 buf, count); 59 /* Flush processor's dcache for this page */ 60 flush_dcache_page(page); 61 kunmap(page); 62 buf += count; 63 write_bytes -= count; 64 65 if (page_fault) 66 break; 67 } 68 return page_fault ? -EFAULT : 0; 69 } 70 71 static void btrfs_drop_pages(struct page **pages, size_t num_pages) 72 { 73 size_t i; 74 for (i = 0; i < num_pages; i++) { 75 if (!pages[i]) 76 break; 77 unlock_page(pages[i]); 78 mark_page_accessed(pages[i]); 79 page_cache_release(pages[i]); 80 } 81 } 82 83 static int insert_inline_extent(struct btrfs_trans_handle *trans, 84 struct btrfs_root *root, struct inode *inode, 85 u64 offset, size_t size, 86 struct page **pages, size_t page_offset, 87 int num_pages) 88 { 89 struct btrfs_key key; 90 struct btrfs_path *path; 91 struct extent_buffer *leaf; 92 char *kaddr; 93 unsigned long ptr; 94 struct btrfs_file_extent_item *ei; 95 struct page *page; 96 u32 datasize; 97 int err = 0; 98 int ret; 99 int i; 100 ssize_t cur_size; 101 102 path = btrfs_alloc_path(); 103 if (!path) 104 return -ENOMEM; 105 106 btrfs_set_trans_block_group(trans, inode); 107 108 key.objectid = inode->i_ino; 109 key.offset = offset; 110 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY); 111 112 ret = btrfs_search_slot(trans, root, &key, path, 0, 1); 113 if (ret < 0) { 114 err = ret; 115 goto fail; 116 } 117 if (ret == 1) { 118 struct btrfs_key found_key; 119 120 if (path->slots[0] == 0) 121 goto insert; 122 123 path->slots[0]--; 124 leaf = path->nodes[0]; 125 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 126 127 if (found_key.objectid != inode->i_ino) 128 goto insert; 129 130 if (found_key.type != BTRFS_EXTENT_DATA_KEY) 131 goto insert; 132 ei = btrfs_item_ptr(leaf, path->slots[0], 133 struct btrfs_file_extent_item); 134 135 if (btrfs_file_extent_type(leaf, ei) != 136 BTRFS_FILE_EXTENT_INLINE) { 137 goto insert; 138 } 139 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 140 ret = 0; 141 } 142 if (ret == 0) { 143 u32 found_size; 144 u64 found_end; 145 146 leaf = path->nodes[0]; 147 ei = btrfs_item_ptr(leaf, path->slots[0], 148 struct btrfs_file_extent_item); 149 150 if (btrfs_file_extent_type(leaf, ei) != 151 BTRFS_FILE_EXTENT_INLINE) { 152 err = ret; 153 btrfs_print_leaf(root, leaf); 154 printk("found wasn't inline offset %Lu inode %lu\n", 155 offset, inode->i_ino); 156 goto fail; 157 } 158 found_size = btrfs_file_extent_inline_len(leaf, 159 btrfs_item_nr(leaf, path->slots[0])); 160 found_end = key.offset + found_size; 161 162 if (found_end < offset + size) { 163 btrfs_release_path(root, path); 164 ret = btrfs_search_slot(trans, root, &key, path, 165 offset + size - found_end, 1); 166 BUG_ON(ret != 0); 167 168 ret = btrfs_extend_item(trans, root, path, 169 offset + size - found_end); 170 if (ret) { 171 err = ret; 172 goto fail; 173 } 174 leaf = path->nodes[0]; 175 ei = btrfs_item_ptr(leaf, path->slots[0], 176 struct btrfs_file_extent_item); 177 } 178 if (found_end < offset) { 179 ptr = btrfs_file_extent_inline_start(ei) + found_size; 180 memset_extent_buffer(leaf, 0, ptr, offset - found_end); 181 } 182 } else { 183 insert: 184 btrfs_release_path(root, path); 185 datasize = offset + size - key.offset; 186 datasize = btrfs_file_extent_calc_inline_size(datasize); 187 ret = btrfs_insert_empty_item(trans, root, path, &key, 188 datasize); 189 if (ret) { 190 err = ret; 191 printk("got bad ret %d\n", ret); 192 goto fail; 193 } 194 leaf = path->nodes[0]; 195 ei = btrfs_item_ptr(leaf, path->slots[0], 196 struct btrfs_file_extent_item); 197 btrfs_set_file_extent_generation(leaf, ei, trans->transid); 198 btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE); 199 } 200 ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset; 201 202 cur_size = size; 203 i = 0; 204 while (size > 0) { 205 page = pages[i]; 206 kaddr = kmap_atomic(page, KM_USER0); 207 cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size); 208 write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size); 209 kunmap_atomic(kaddr, KM_USER0); 210 page_offset = 0; 211 ptr += cur_size; 212 size -= cur_size; 213 if (i >= num_pages) { 214 printk("i %d num_pages %d\n", i, num_pages); 215 } 216 i++; 217 } 218 btrfs_mark_buffer_dirty(leaf); 219 fail: 220 btrfs_free_path(path); 221 return err; 222 } 223 224 static int dirty_and_release_pages(struct btrfs_trans_handle *trans, 225 struct btrfs_root *root, 226 struct file *file, 227 struct page **pages, 228 size_t num_pages, 229 loff_t pos, 230 size_t write_bytes) 231 { 232 int err = 0; 233 int i; 234 struct inode *inode = fdentry(file)->d_inode; 235 struct extent_map *em; 236 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 237 u64 hint_byte; 238 u64 num_bytes; 239 u64 start_pos; 240 u64 end_of_last_block; 241 u64 end_pos = pos + write_bytes; 242 u64 inline_size; 243 loff_t isize = i_size_read(inode); 244 em = alloc_extent_map(GFP_NOFS); 245 if (!em) 246 return -ENOMEM; 247 248 em->bdev = inode->i_sb->s_bdev; 249 250 start_pos = pos & ~((u64)root->sectorsize - 1); 251 num_bytes = (write_bytes + pos - start_pos + 252 root->sectorsize - 1) & ~((u64)root->sectorsize - 1); 253 254 down_read(&BTRFS_I(inode)->root->snap_sem); 255 end_of_last_block = start_pos + num_bytes - 1; 256 257 lock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS); 258 mutex_lock(&root->fs_info->fs_mutex); 259 trans = btrfs_start_transaction(root, 1); 260 if (!trans) { 261 err = -ENOMEM; 262 goto out_unlock; 263 } 264 btrfs_set_trans_block_group(trans, inode); 265 inode->i_blocks += num_bytes >> 9; 266 hint_byte = 0; 267 268 if ((end_of_last_block & 4095) == 0) { 269 printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block); 270 } 271 set_extent_uptodate(em_tree, start_pos, end_of_last_block, GFP_NOFS); 272 273 /* FIXME...EIEIO, ENOSPC and more */ 274 275 /* insert any holes we need to create */ 276 if (inode->i_size < start_pos) { 277 u64 last_pos_in_file; 278 u64 hole_size; 279 u64 mask = root->sectorsize - 1; 280 last_pos_in_file = (isize + mask) & ~mask; 281 hole_size = (start_pos - last_pos_in_file + mask) & ~mask; 282 283 if (last_pos_in_file < start_pos) { 284 err = btrfs_drop_extents(trans, root, inode, 285 last_pos_in_file, 286 last_pos_in_file + hole_size, 287 last_pos_in_file, 288 &hint_byte); 289 if (err) 290 goto failed; 291 292 err = btrfs_insert_file_extent(trans, root, 293 inode->i_ino, 294 last_pos_in_file, 295 0, 0, hole_size); 296 } 297 if (err) 298 goto failed; 299 } 300 301 /* 302 * either allocate an extent for the new bytes or setup the key 303 * to show we are doing inline data in the extent 304 */ 305 inline_size = end_pos; 306 if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) || 307 inline_size > 32768 || 308 inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) { 309 u64 last_end; 310 311 for (i = 0; i < num_pages; i++) { 312 struct page *p = pages[i]; 313 SetPageUptodate(p); 314 set_page_dirty(p); 315 } 316 last_end = (u64)(pages[num_pages -1]->index) << 317 PAGE_CACHE_SHIFT; 318 last_end += PAGE_CACHE_SIZE - 1; 319 set_extent_delalloc(em_tree, start_pos, end_of_last_block, 320 GFP_NOFS); 321 } else { 322 u64 aligned_end; 323 /* step one, delete the existing extents in this range */ 324 aligned_end = (pos + write_bytes + root->sectorsize - 1) & 325 ~((u64)root->sectorsize - 1); 326 err = btrfs_drop_extents(trans, root, inode, start_pos, 327 aligned_end, aligned_end, &hint_byte); 328 if (err) 329 goto failed; 330 if (isize > inline_size) 331 inline_size = min_t(u64, isize, aligned_end); 332 inline_size -= start_pos; 333 err = insert_inline_extent(trans, root, inode, start_pos, 334 inline_size, pages, 0, num_pages); 335 BUG_ON(err); 336 } 337 if (end_pos > isize) { 338 i_size_write(inode, end_pos); 339 btrfs_update_inode(trans, root, inode); 340 } 341 failed: 342 err = btrfs_end_transaction(trans, root); 343 out_unlock: 344 mutex_unlock(&root->fs_info->fs_mutex); 345 unlock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS); 346 free_extent_map(em); 347 up_read(&BTRFS_I(inode)->root->snap_sem); 348 return err; 349 } 350 351 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end) 352 { 353 struct extent_map *em; 354 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 355 356 while(1) { 357 em = lookup_extent_mapping(em_tree, start, end); 358 if (!em) 359 break; 360 remove_extent_mapping(em_tree, em); 361 /* once for us */ 362 free_extent_map(em); 363 /* once for the tree*/ 364 free_extent_map(em); 365 } 366 return 0; 367 } 368 369 /* 370 * this is very complex, but the basic idea is to drop all extents 371 * in the range start - end. hint_block is filled in with a block number 372 * that would be a good hint to the block allocator for this file. 373 * 374 * If an extent intersects the range but is not entirely inside the range 375 * it is either truncated or split. Anything entirely inside the range 376 * is deleted from the tree. 377 */ 378 int btrfs_drop_extents(struct btrfs_trans_handle *trans, 379 struct btrfs_root *root, struct inode *inode, 380 u64 start, u64 end, u64 inline_limit, u64 *hint_byte) 381 { 382 u64 extent_end = 0; 383 u64 search_start = start; 384 struct extent_buffer *leaf; 385 struct btrfs_file_extent_item *extent; 386 struct btrfs_path *path; 387 struct btrfs_key key; 388 struct btrfs_file_extent_item old; 389 int keep; 390 int slot; 391 int bookend; 392 int found_type; 393 int found_extent; 394 int found_inline; 395 int recow; 396 int ret; 397 398 btrfs_drop_extent_cache(inode, start, end - 1); 399 400 path = btrfs_alloc_path(); 401 if (!path) 402 return -ENOMEM; 403 while(1) { 404 recow = 0; 405 btrfs_release_path(root, path); 406 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, 407 search_start, -1); 408 if (ret < 0) 409 goto out; 410 if (ret > 0) { 411 if (path->slots[0] == 0) { 412 ret = 0; 413 goto out; 414 } 415 path->slots[0]--; 416 } 417 next_slot: 418 keep = 0; 419 bookend = 0; 420 found_extent = 0; 421 found_inline = 0; 422 extent = NULL; 423 leaf = path->nodes[0]; 424 slot = path->slots[0]; 425 ret = 0; 426 btrfs_item_key_to_cpu(leaf, &key, slot); 427 if (key.offset >= end || key.objectid != inode->i_ino) { 428 goto out; 429 } 430 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY) { 431 goto out; 432 } 433 if (recow) { 434 search_start = key.offset; 435 continue; 436 } 437 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) { 438 extent = btrfs_item_ptr(leaf, slot, 439 struct btrfs_file_extent_item); 440 found_type = btrfs_file_extent_type(leaf, extent); 441 if (found_type == BTRFS_FILE_EXTENT_REG) { 442 extent_end = 443 btrfs_file_extent_disk_bytenr(leaf, 444 extent); 445 if (extent_end) 446 *hint_byte = extent_end; 447 448 extent_end = key.offset + 449 btrfs_file_extent_num_bytes(leaf, extent); 450 found_extent = 1; 451 } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { 452 struct btrfs_item *item; 453 item = btrfs_item_nr(leaf, slot); 454 found_inline = 1; 455 extent_end = key.offset + 456 btrfs_file_extent_inline_len(leaf, item); 457 } 458 } else { 459 extent_end = search_start; 460 } 461 462 /* we found nothing we can drop */ 463 if ((!found_extent && !found_inline) || 464 search_start >= extent_end) { 465 int nextret; 466 u32 nritems; 467 nritems = btrfs_header_nritems(leaf); 468 if (slot >= nritems - 1) { 469 nextret = btrfs_next_leaf(root, path); 470 if (nextret) 471 goto out; 472 recow = 1; 473 } else { 474 path->slots[0]++; 475 } 476 goto next_slot; 477 } 478 479 if (found_inline) { 480 u64 mask = root->sectorsize - 1; 481 search_start = (extent_end + mask) & ~mask; 482 } else 483 search_start = extent_end; 484 if (end <= extent_end && start >= key.offset && found_inline) { 485 *hint_byte = EXTENT_MAP_INLINE; 486 continue; 487 } 488 if (end < extent_end && end >= key.offset) { 489 if (found_extent) { 490 u64 disk_bytenr = 491 btrfs_file_extent_disk_bytenr(leaf, extent); 492 u64 disk_num_bytes = 493 btrfs_file_extent_disk_num_bytes(leaf, 494 extent); 495 read_extent_buffer(leaf, &old, 496 (unsigned long)extent, 497 sizeof(old)); 498 if (disk_bytenr != 0) { 499 ret = btrfs_inc_extent_ref(trans, root, 500 disk_bytenr, disk_num_bytes, 501 root->root_key.objectid, 502 trans->transid, 503 key.objectid, end); 504 BUG_ON(ret); 505 } 506 } 507 bookend = 1; 508 if (found_inline && start <= key.offset && 509 inline_limit < extent_end) 510 keep = 1; 511 } 512 /* truncate existing extent */ 513 if (start > key.offset) { 514 u64 new_num; 515 u64 old_num; 516 keep = 1; 517 WARN_ON(start & (root->sectorsize - 1)); 518 if (found_extent) { 519 new_num = start - key.offset; 520 old_num = btrfs_file_extent_num_bytes(leaf, 521 extent); 522 *hint_byte = 523 btrfs_file_extent_disk_bytenr(leaf, 524 extent); 525 if (btrfs_file_extent_disk_bytenr(leaf, 526 extent)) { 527 inode->i_blocks -= 528 (old_num - new_num) >> 9; 529 } 530 btrfs_set_file_extent_num_bytes(leaf, extent, 531 new_num); 532 btrfs_mark_buffer_dirty(leaf); 533 } else if (key.offset < inline_limit && 534 (end > extent_end) && 535 (inline_limit < extent_end)) { 536 u32 new_size; 537 new_size = btrfs_file_extent_calc_inline_size( 538 inline_limit - key.offset); 539 btrfs_truncate_item(trans, root, path, 540 new_size, 1); 541 } 542 } 543 /* delete the entire extent */ 544 if (!keep) { 545 u64 disk_bytenr = 0; 546 u64 disk_num_bytes = 0; 547 u64 extent_num_bytes = 0; 548 u64 root_gen; 549 u64 root_owner; 550 551 root_gen = btrfs_header_generation(leaf); 552 root_owner = btrfs_header_owner(leaf); 553 if (found_extent) { 554 disk_bytenr = 555 btrfs_file_extent_disk_bytenr(leaf, 556 extent); 557 disk_num_bytes = 558 btrfs_file_extent_disk_num_bytes(leaf, 559 extent); 560 extent_num_bytes = 561 btrfs_file_extent_num_bytes(leaf, extent); 562 *hint_byte = 563 btrfs_file_extent_disk_bytenr(leaf, 564 extent); 565 } 566 ret = btrfs_del_item(trans, root, path); 567 /* TODO update progress marker and return */ 568 BUG_ON(ret); 569 btrfs_release_path(root, path); 570 extent = NULL; 571 if (found_extent && disk_bytenr != 0) { 572 inode->i_blocks -= extent_num_bytes >> 9; 573 ret = btrfs_free_extent(trans, root, 574 disk_bytenr, 575 disk_num_bytes, 576 root_owner, 577 root_gen, inode->i_ino, 578 key.offset, 0); 579 } 580 581 BUG_ON(ret); 582 if (!bookend && search_start >= end) { 583 ret = 0; 584 goto out; 585 } 586 if (!bookend) 587 continue; 588 } 589 if (bookend && found_inline && start <= key.offset && 590 inline_limit < extent_end && key.offset <= inline_limit) { 591 u32 new_size; 592 new_size = btrfs_file_extent_calc_inline_size( 593 extent_end - inline_limit); 594 btrfs_truncate_item(trans, root, path, new_size, 0); 595 } 596 /* create bookend, splitting the extent in two */ 597 if (bookend && found_extent) { 598 struct btrfs_key ins; 599 ins.objectid = inode->i_ino; 600 ins.offset = end; 601 btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY); 602 btrfs_release_path(root, path); 603 ret = btrfs_insert_empty_item(trans, root, path, &ins, 604 sizeof(*extent)); 605 606 leaf = path->nodes[0]; 607 if (ret) { 608 btrfs_print_leaf(root, leaf); 609 printk("got %d on inserting %Lu %u %Lu start %Lu end %Lu found %Lu %Lu keep was %d\n", ret , ins.objectid, ins.type, ins.offset, start, end, key.offset, extent_end, keep); 610 } 611 BUG_ON(ret); 612 extent = btrfs_item_ptr(leaf, path->slots[0], 613 struct btrfs_file_extent_item); 614 write_extent_buffer(leaf, &old, 615 (unsigned long)extent, sizeof(old)); 616 617 btrfs_set_file_extent_offset(leaf, extent, 618 le64_to_cpu(old.offset) + end - key.offset); 619 WARN_ON(le64_to_cpu(old.num_bytes) < 620 (extent_end - end)); 621 btrfs_set_file_extent_num_bytes(leaf, extent, 622 extent_end - end); 623 btrfs_set_file_extent_type(leaf, extent, 624 BTRFS_FILE_EXTENT_REG); 625 626 btrfs_mark_buffer_dirty(path->nodes[0]); 627 if (le64_to_cpu(old.disk_bytenr) != 0) { 628 inode->i_blocks += 629 btrfs_file_extent_num_bytes(leaf, 630 extent) >> 9; 631 } 632 ret = 0; 633 goto out; 634 } 635 } 636 out: 637 btrfs_free_path(path); 638 return ret; 639 } 640 641 /* 642 * this gets pages into the page cache and locks them down 643 */ 644 static int prepare_pages(struct btrfs_root *root, 645 struct file *file, 646 struct page **pages, 647 size_t num_pages, 648 loff_t pos, 649 unsigned long first_index, 650 unsigned long last_index, 651 size_t write_bytes) 652 { 653 int i; 654 unsigned long index = pos >> PAGE_CACHE_SHIFT; 655 struct inode *inode = fdentry(file)->d_inode; 656 int err = 0; 657 u64 start_pos; 658 659 start_pos = pos & ~((u64)root->sectorsize - 1); 660 661 memset(pages, 0, num_pages * sizeof(struct page *)); 662 663 for (i = 0; i < num_pages; i++) { 664 pages[i] = grab_cache_page(inode->i_mapping, index + i); 665 if (!pages[i]) { 666 err = -ENOMEM; 667 BUG_ON(1); 668 } 669 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18) 670 ClearPageDirty(pages[i]); 671 #else 672 cancel_dirty_page(pages[i], PAGE_CACHE_SIZE); 673 #endif 674 wait_on_page_writeback(pages[i]); 675 set_page_extent_mapped(pages[i]); 676 WARN_ON(!PageLocked(pages[i])); 677 } 678 return 0; 679 } 680 681 static ssize_t btrfs_file_write(struct file *file, const char __user *buf, 682 size_t count, loff_t *ppos) 683 { 684 loff_t pos; 685 loff_t start_pos; 686 ssize_t num_written = 0; 687 ssize_t err = 0; 688 int ret = 0; 689 struct inode *inode = fdentry(file)->d_inode; 690 struct btrfs_root *root = BTRFS_I(inode)->root; 691 struct page **pages = NULL; 692 int nrptrs; 693 struct page *pinned[2]; 694 unsigned long first_index; 695 unsigned long last_index; 696 697 nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, 698 PAGE_CACHE_SIZE / (sizeof(struct page *))); 699 pinned[0] = NULL; 700 pinned[1] = NULL; 701 if (file->f_flags & O_DIRECT) 702 return -EINVAL; 703 704 pos = *ppos; 705 start_pos = pos; 706 707 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); 708 current->backing_dev_info = inode->i_mapping->backing_dev_info; 709 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); 710 if (err) 711 goto out; 712 if (count == 0) 713 goto out; 714 err = remove_suid(fdentry(file)); 715 if (err) 716 goto out; 717 file_update_time(file); 718 719 pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); 720 721 mutex_lock(&inode->i_mutex); 722 first_index = pos >> PAGE_CACHE_SHIFT; 723 last_index = (pos + count) >> PAGE_CACHE_SHIFT; 724 725 /* 726 * there are lots of better ways to do this, but this code 727 * makes sure the first and last page in the file range are 728 * up to date and ready for cow 729 */ 730 if ((pos & (PAGE_CACHE_SIZE - 1))) { 731 pinned[0] = grab_cache_page(inode->i_mapping, first_index); 732 if (!PageUptodate(pinned[0])) { 733 ret = btrfs_readpage(NULL, pinned[0]); 734 BUG_ON(ret); 735 wait_on_page_locked(pinned[0]); 736 } else { 737 unlock_page(pinned[0]); 738 } 739 } 740 if ((pos + count) & (PAGE_CACHE_SIZE - 1)) { 741 pinned[1] = grab_cache_page(inode->i_mapping, last_index); 742 if (!PageUptodate(pinned[1])) { 743 ret = btrfs_readpage(NULL, pinned[1]); 744 BUG_ON(ret); 745 wait_on_page_locked(pinned[1]); 746 } else { 747 unlock_page(pinned[1]); 748 } 749 } 750 751 while(count > 0) { 752 size_t offset = pos & (PAGE_CACHE_SIZE - 1); 753 size_t write_bytes = min(count, nrptrs * 754 (size_t)PAGE_CACHE_SIZE - 755 offset); 756 size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> 757 PAGE_CACHE_SHIFT; 758 759 WARN_ON(num_pages > nrptrs); 760 memset(pages, 0, sizeof(pages)); 761 ret = prepare_pages(root, file, pages, num_pages, 762 pos, first_index, last_index, 763 write_bytes); 764 if (ret) 765 goto out; 766 767 ret = btrfs_copy_from_user(pos, num_pages, 768 write_bytes, pages, buf); 769 if (ret) { 770 btrfs_drop_pages(pages, num_pages); 771 goto out; 772 } 773 774 ret = dirty_and_release_pages(NULL, root, file, pages, 775 num_pages, pos, write_bytes); 776 btrfs_drop_pages(pages, num_pages); 777 if (ret) 778 goto out; 779 780 buf += write_bytes; 781 count -= write_bytes; 782 pos += write_bytes; 783 num_written += write_bytes; 784 785 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages); 786 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1) 787 btrfs_btree_balance_dirty(root, 1); 788 cond_resched(); 789 } 790 mutex_unlock(&inode->i_mutex); 791 out: 792 kfree(pages); 793 if (pinned[0]) 794 page_cache_release(pinned[0]); 795 if (pinned[1]) 796 page_cache_release(pinned[1]); 797 *ppos = pos; 798 799 if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { 800 err = sync_page_range(inode, inode->i_mapping, 801 start_pos, num_written); 802 if (err < 0) 803 num_written = err; 804 } 805 current->backing_dev_info = NULL; 806 return num_written ? num_written : err; 807 } 808 809 static int btrfs_sync_file(struct file *file, 810 struct dentry *dentry, int datasync) 811 { 812 struct inode *inode = dentry->d_inode; 813 struct btrfs_root *root = BTRFS_I(inode)->root; 814 int ret = 0; 815 struct btrfs_trans_handle *trans; 816 817 /* 818 * check the transaction that last modified this inode 819 * and see if its already been committed 820 */ 821 mutex_lock(&root->fs_info->fs_mutex); 822 if (!BTRFS_I(inode)->last_trans) 823 goto out; 824 mutex_lock(&root->fs_info->trans_mutex); 825 if (BTRFS_I(inode)->last_trans <= 826 root->fs_info->last_trans_committed) { 827 BTRFS_I(inode)->last_trans = 0; 828 mutex_unlock(&root->fs_info->trans_mutex); 829 goto out; 830 } 831 mutex_unlock(&root->fs_info->trans_mutex); 832 833 /* 834 * ok we haven't committed the transaction yet, lets do a commit 835 */ 836 trans = btrfs_start_transaction(root, 1); 837 if (!trans) { 838 ret = -ENOMEM; 839 goto out; 840 } 841 ret = btrfs_commit_transaction(trans, root); 842 out: 843 mutex_unlock(&root->fs_info->fs_mutex); 844 return ret > 0 ? EIO : ret; 845 } 846 847 static struct vm_operations_struct btrfs_file_vm_ops = { 848 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23) 849 .nopage = filemap_nopage, 850 .populate = filemap_populate, 851 #else 852 .fault = filemap_fault, 853 #endif 854 .page_mkwrite = btrfs_page_mkwrite, 855 }; 856 857 static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) 858 { 859 vma->vm_ops = &btrfs_file_vm_ops; 860 file_accessed(filp); 861 return 0; 862 } 863 864 struct file_operations btrfs_file_operations = { 865 .llseek = generic_file_llseek, 866 .read = do_sync_read, 867 .aio_read = generic_file_aio_read, 868 .splice_read = generic_file_splice_read, 869 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18) 870 .sendfile = generic_file_sendfile, 871 #endif 872 .write = btrfs_file_write, 873 .mmap = btrfs_file_mmap, 874 .open = generic_file_open, 875 .fsync = btrfs_sync_file, 876 .unlocked_ioctl = btrfs_ioctl, 877 #ifdef CONFIG_COMPAT 878 .compat_ioctl = btrfs_ioctl, 879 #endif 880 }; 881 882