1 /* 2 * linux/fs/ext4/inode.c 3 * 4 * Copyright (C) 1992, 1993, 1994, 1995 5 * Remy Card (card@masi.ibp.fr) 6 * Laboratoire MASI - Institut Blaise Pascal 7 * Universite Pierre et Marie Curie (Paris VI) 8 * 9 * from 10 * 11 * linux/fs/minix/inode.c 12 * 13 * Copyright (C) 1991, 1992 Linus Torvalds 14 * 15 * Goal-directed block allocation by Stephen Tweedie 16 * (sct@redhat.com), 1993, 1998 17 * Big-endian to little-endian byte-swapping/bitmaps by 18 * David S. Miller (davem@caip.rutgers.edu), 1995 19 * 64-bit file support on 64-bit platforms by Jakub Jelinek 20 * (jj@sunsite.ms.mff.cuni.cz) 21 * 22 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000 23 */ 24 25 #include <linux/module.h> 26 #include <linux/fs.h> 27 #include <linux/time.h> 28 #include <linux/jbd2.h> 29 #include <linux/highuid.h> 30 #include <linux/pagemap.h> 31 #include <linux/quotaops.h> 32 #include <linux/string.h> 33 #include <linux/buffer_head.h> 34 #include <linux/writeback.h> 35 #include <linux/pagevec.h> 36 #include <linux/mpage.h> 37 #include <linux/namei.h> 38 #include <linux/uio.h> 39 #include <linux/bio.h> 40 #include <linux/workqueue.h> 41 #include <linux/kernel.h> 42 #include <linux/slab.h> 43 44 #include "ext4_jbd2.h" 45 #include "xattr.h" 46 #include "acl.h" 47 #include "ext4_extents.h" 48 49 #include <trace/events/ext4.h> 50 51 #define MPAGE_DA_EXTENT_TAIL 0x01 52 53 static inline int ext4_begin_ordered_truncate(struct inode *inode, 54 loff_t new_size) 55 { 56 return jbd2_journal_begin_ordered_truncate( 57 EXT4_SB(inode->i_sb)->s_journal, 58 &EXT4_I(inode)->jinode, 59 new_size); 60 } 61 62 static void ext4_invalidatepage(struct page *page, unsigned long offset); 63 64 /* 65 * Test whether an inode is a fast symlink. 66 */ 67 static int ext4_inode_is_fast_symlink(struct inode *inode) 68 { 69 int ea_blocks = EXT4_I(inode)->i_file_acl ? 70 (inode->i_sb->s_blocksize >> 9) : 0; 71 72 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); 73 } 74 75 /* 76 * Work out how many blocks we need to proceed with the next chunk of a 77 * truncate transaction. 78 */ 79 static unsigned long blocks_for_truncate(struct inode *inode) 80 { 81 ext4_lblk_t needed; 82 83 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 84 85 /* Give ourselves just enough room to cope with inodes in which 86 * i_blocks is corrupt: we've seen disk corruptions in the past 87 * which resulted in random data in an inode which looked enough 88 * like a regular file for ext4 to try to delete it. Things 89 * will go a bit crazy if that happens, but at least we should 90 * try not to panic the whole kernel. */ 91 if (needed < 2) 92 needed = 2; 93 94 /* But we need to bound the transaction so we don't overflow the 95 * journal. */ 96 if (needed > EXT4_MAX_TRANS_DATA) 97 needed = EXT4_MAX_TRANS_DATA; 98 99 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 100 } 101 102 /* 103 * Truncate transactions can be complex and absolutely huge. So we need to 104 * be able to restart the transaction at a conventient checkpoint to make 105 * sure we don't overflow the journal. 106 * 107 * start_transaction gets us a new handle for a truncate transaction, 108 * and extend_transaction tries to extend the existing one a bit. If 109 * extend fails, we need to propagate the failure up and restart the 110 * transaction in the top-level truncate loop. --sct 111 */ 112 static handle_t *start_transaction(struct inode *inode) 113 { 114 handle_t *result; 115 116 result = ext4_journal_start(inode, blocks_for_truncate(inode)); 117 if (!IS_ERR(result)) 118 return result; 119 120 ext4_std_error(inode->i_sb, PTR_ERR(result)); 121 return result; 122 } 123 124 /* 125 * Try to extend this transaction for the purposes of truncation. 126 * 127 * Returns 0 if we managed to create more room. If we can't create more 128 * room, and the transaction must be restarted we return 1. 129 */ 130 static int try_to_extend_transaction(handle_t *handle, struct inode *inode) 131 { 132 if (!ext4_handle_valid(handle)) 133 return 0; 134 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1)) 135 return 0; 136 if (!ext4_journal_extend(handle, blocks_for_truncate(inode))) 137 return 0; 138 return 1; 139 } 140 141 /* 142 * Restart the transaction associated with *handle. This does a commit, 143 * so before we call here everything must be consistently dirtied against 144 * this transaction. 145 */ 146 int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode, 147 int nblocks) 148 { 149 int ret; 150 151 /* 152 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this 153 * moment, get_block can be called only for blocks inside i_size since 154 * page cache has been already dropped and writes are blocked by 155 * i_mutex. So we can safely drop the i_data_sem here. 156 */ 157 BUG_ON(EXT4_JOURNAL(inode) == NULL); 158 jbd_debug(2, "restarting handle %p\n", handle); 159 up_write(&EXT4_I(inode)->i_data_sem); 160 ret = ext4_journal_restart(handle, blocks_for_truncate(inode)); 161 down_write(&EXT4_I(inode)->i_data_sem); 162 ext4_discard_preallocations(inode); 163 164 return ret; 165 } 166 167 /* 168 * Called at the last iput() if i_nlink is zero. 169 */ 170 void ext4_delete_inode(struct inode *inode) 171 { 172 handle_t *handle; 173 int err; 174 175 if (!is_bad_inode(inode)) 176 dquot_initialize(inode); 177 178 if (ext4_should_order_data(inode)) 179 ext4_begin_ordered_truncate(inode, 0); 180 truncate_inode_pages(&inode->i_data, 0); 181 182 if (is_bad_inode(inode)) 183 goto no_delete; 184 185 handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3); 186 if (IS_ERR(handle)) { 187 ext4_std_error(inode->i_sb, PTR_ERR(handle)); 188 /* 189 * If we're going to skip the normal cleanup, we still need to 190 * make sure that the in-core orphan linked list is properly 191 * cleaned up. 192 */ 193 ext4_orphan_del(NULL, inode); 194 goto no_delete; 195 } 196 197 if (IS_SYNC(inode)) 198 ext4_handle_sync(handle); 199 inode->i_size = 0; 200 err = ext4_mark_inode_dirty(handle, inode); 201 if (err) { 202 ext4_warning(inode->i_sb, 203 "couldn't mark inode dirty (err %d)", err); 204 goto stop_handle; 205 } 206 if (inode->i_blocks) 207 ext4_truncate(inode); 208 209 /* 210 * ext4_ext_truncate() doesn't reserve any slop when it 211 * restarts journal transactions; therefore there may not be 212 * enough credits left in the handle to remove the inode from 213 * the orphan list and set the dtime field. 214 */ 215 if (!ext4_handle_has_enough_credits(handle, 3)) { 216 err = ext4_journal_extend(handle, 3); 217 if (err > 0) 218 err = ext4_journal_restart(handle, 3); 219 if (err != 0) { 220 ext4_warning(inode->i_sb, 221 "couldn't extend journal (err %d)", err); 222 stop_handle: 223 ext4_journal_stop(handle); 224 goto no_delete; 225 } 226 } 227 228 /* 229 * Kill off the orphan record which ext4_truncate created. 230 * AKPM: I think this can be inside the above `if'. 231 * Note that ext4_orphan_del() has to be able to cope with the 232 * deletion of a non-existent orphan - this is because we don't 233 * know if ext4_truncate() actually created an orphan record. 234 * (Well, we could do this if we need to, but heck - it works) 235 */ 236 ext4_orphan_del(handle, inode); 237 EXT4_I(inode)->i_dtime = get_seconds(); 238 239 /* 240 * One subtle ordering requirement: if anything has gone wrong 241 * (transaction abort, IO errors, whatever), then we can still 242 * do these next steps (the fs will already have been marked as 243 * having errors), but we can't free the inode if the mark_dirty 244 * fails. 245 */ 246 if (ext4_mark_inode_dirty(handle, inode)) 247 /* If that failed, just do the required in-core inode clear. */ 248 clear_inode(inode); 249 else 250 ext4_free_inode(handle, inode); 251 ext4_journal_stop(handle); 252 return; 253 no_delete: 254 clear_inode(inode); /* We must guarantee clearing of inode... */ 255 } 256 257 typedef struct { 258 __le32 *p; 259 __le32 key; 260 struct buffer_head *bh; 261 } Indirect; 262 263 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v) 264 { 265 p->key = *(p->p = v); 266 p->bh = bh; 267 } 268 269 /** 270 * ext4_block_to_path - parse the block number into array of offsets 271 * @inode: inode in question (we are only interested in its superblock) 272 * @i_block: block number to be parsed 273 * @offsets: array to store the offsets in 274 * @boundary: set this non-zero if the referred-to block is likely to be 275 * followed (on disk) by an indirect block. 276 * 277 * To store the locations of file's data ext4 uses a data structure common 278 * for UNIX filesystems - tree of pointers anchored in the inode, with 279 * data blocks at leaves and indirect blocks in intermediate nodes. 280 * This function translates the block number into path in that tree - 281 * return value is the path length and @offsets[n] is the offset of 282 * pointer to (n+1)th node in the nth one. If @block is out of range 283 * (negative or too large) warning is printed and zero returned. 284 * 285 * Note: function doesn't find node addresses, so no IO is needed. All 286 * we need to know is the capacity of indirect blocks (taken from the 287 * inode->i_sb). 288 */ 289 290 /* 291 * Portability note: the last comparison (check that we fit into triple 292 * indirect block) is spelled differently, because otherwise on an 293 * architecture with 32-bit longs and 8Kb pages we might get into trouble 294 * if our filesystem had 8Kb blocks. We might use long long, but that would 295 * kill us on x86. Oh, well, at least the sign propagation does not matter - 296 * i_block would have to be negative in the very beginning, so we would not 297 * get there at all. 298 */ 299 300 static int ext4_block_to_path(struct inode *inode, 301 ext4_lblk_t i_block, 302 ext4_lblk_t offsets[4], int *boundary) 303 { 304 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb); 305 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb); 306 const long direct_blocks = EXT4_NDIR_BLOCKS, 307 indirect_blocks = ptrs, 308 double_blocks = (1 << (ptrs_bits * 2)); 309 int n = 0; 310 int final = 0; 311 312 if (i_block < direct_blocks) { 313 offsets[n++] = i_block; 314 final = direct_blocks; 315 } else if ((i_block -= direct_blocks) < indirect_blocks) { 316 offsets[n++] = EXT4_IND_BLOCK; 317 offsets[n++] = i_block; 318 final = ptrs; 319 } else if ((i_block -= indirect_blocks) < double_blocks) { 320 offsets[n++] = EXT4_DIND_BLOCK; 321 offsets[n++] = i_block >> ptrs_bits; 322 offsets[n++] = i_block & (ptrs - 1); 323 final = ptrs; 324 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) { 325 offsets[n++] = EXT4_TIND_BLOCK; 326 offsets[n++] = i_block >> (ptrs_bits * 2); 327 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1); 328 offsets[n++] = i_block & (ptrs - 1); 329 final = ptrs; 330 } else { 331 ext4_warning(inode->i_sb, "block %lu > max in inode %lu", 332 i_block + direct_blocks + 333 indirect_blocks + double_blocks, inode->i_ino); 334 } 335 if (boundary) 336 *boundary = final - 1 - (i_block & (ptrs - 1)); 337 return n; 338 } 339 340 static int __ext4_check_blockref(const char *function, struct inode *inode, 341 __le32 *p, unsigned int max) 342 { 343 __le32 *bref = p; 344 unsigned int blk; 345 346 while (bref < p+max) { 347 blk = le32_to_cpu(*bref++); 348 if (blk && 349 unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb), 350 blk, 1))) { 351 ext4_error_inode(function, inode, 352 "invalid block reference %u", blk); 353 return -EIO; 354 } 355 } 356 return 0; 357 } 358 359 360 #define ext4_check_indirect_blockref(inode, bh) \ 361 __ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data, \ 362 EXT4_ADDR_PER_BLOCK((inode)->i_sb)) 363 364 #define ext4_check_inode_blockref(inode) \ 365 __ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data, \ 366 EXT4_NDIR_BLOCKS) 367 368 /** 369 * ext4_get_branch - read the chain of indirect blocks leading to data 370 * @inode: inode in question 371 * @depth: depth of the chain (1 - direct pointer, etc.) 372 * @offsets: offsets of pointers in inode/indirect blocks 373 * @chain: place to store the result 374 * @err: here we store the error value 375 * 376 * Function fills the array of triples <key, p, bh> and returns %NULL 377 * if everything went OK or the pointer to the last filled triple 378 * (incomplete one) otherwise. Upon the return chain[i].key contains 379 * the number of (i+1)-th block in the chain (as it is stored in memory, 380 * i.e. little-endian 32-bit), chain[i].p contains the address of that 381 * number (it points into struct inode for i==0 and into the bh->b_data 382 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect 383 * block for i>0 and NULL for i==0. In other words, it holds the block 384 * numbers of the chain, addresses they were taken from (and where we can 385 * verify that chain did not change) and buffer_heads hosting these 386 * numbers. 387 * 388 * Function stops when it stumbles upon zero pointer (absent block) 389 * (pointer to last triple returned, *@err == 0) 390 * or when it gets an IO error reading an indirect block 391 * (ditto, *@err == -EIO) 392 * or when it reads all @depth-1 indirect blocks successfully and finds 393 * the whole chain, all way to the data (returns %NULL, *err == 0). 394 * 395 * Need to be called with 396 * down_read(&EXT4_I(inode)->i_data_sem) 397 */ 398 static Indirect *ext4_get_branch(struct inode *inode, int depth, 399 ext4_lblk_t *offsets, 400 Indirect chain[4], int *err) 401 { 402 struct super_block *sb = inode->i_sb; 403 Indirect *p = chain; 404 struct buffer_head *bh; 405 406 *err = 0; 407 /* i_data is not going away, no lock needed */ 408 add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets); 409 if (!p->key) 410 goto no_block; 411 while (--depth) { 412 bh = sb_getblk(sb, le32_to_cpu(p->key)); 413 if (unlikely(!bh)) 414 goto failure; 415 416 if (!bh_uptodate_or_lock(bh)) { 417 if (bh_submit_read(bh) < 0) { 418 put_bh(bh); 419 goto failure; 420 } 421 /* validate block references */ 422 if (ext4_check_indirect_blockref(inode, bh)) { 423 put_bh(bh); 424 goto failure; 425 } 426 } 427 428 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets); 429 /* Reader: end */ 430 if (!p->key) 431 goto no_block; 432 } 433 return NULL; 434 435 failure: 436 *err = -EIO; 437 no_block: 438 return p; 439 } 440 441 /** 442 * ext4_find_near - find a place for allocation with sufficient locality 443 * @inode: owner 444 * @ind: descriptor of indirect block. 445 * 446 * This function returns the preferred place for block allocation. 447 * It is used when heuristic for sequential allocation fails. 448 * Rules are: 449 * + if there is a block to the left of our position - allocate near it. 450 * + if pointer will live in indirect block - allocate near that block. 451 * + if pointer will live in inode - allocate in the same 452 * cylinder group. 453 * 454 * In the latter case we colour the starting block by the callers PID to 455 * prevent it from clashing with concurrent allocations for a different inode 456 * in the same block group. The PID is used here so that functionally related 457 * files will be close-by on-disk. 458 * 459 * Caller must make sure that @ind is valid and will stay that way. 460 */ 461 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind) 462 { 463 struct ext4_inode_info *ei = EXT4_I(inode); 464 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data; 465 __le32 *p; 466 ext4_fsblk_t bg_start; 467 ext4_fsblk_t last_block; 468 ext4_grpblk_t colour; 469 ext4_group_t block_group; 470 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); 471 472 /* Try to find previous block */ 473 for (p = ind->p - 1; p >= start; p--) { 474 if (*p) 475 return le32_to_cpu(*p); 476 } 477 478 /* No such thing, so let's try location of indirect block */ 479 if (ind->bh) 480 return ind->bh->b_blocknr; 481 482 /* 483 * It is going to be referred to from the inode itself? OK, just put it 484 * into the same cylinder group then. 485 */ 486 block_group = ei->i_block_group; 487 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { 488 block_group &= ~(flex_size-1); 489 if (S_ISREG(inode->i_mode)) 490 block_group++; 491 } 492 bg_start = ext4_group_first_block_no(inode->i_sb, block_group); 493 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; 494 495 /* 496 * If we are doing delayed allocation, we don't need take 497 * colour into account. 498 */ 499 if (test_opt(inode->i_sb, DELALLOC)) 500 return bg_start; 501 502 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) 503 colour = (current->pid % 16) * 504 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); 505 else 506 colour = (current->pid % 16) * ((last_block - bg_start) / 16); 507 return bg_start + colour; 508 } 509 510 /** 511 * ext4_find_goal - find a preferred place for allocation. 512 * @inode: owner 513 * @block: block we want 514 * @partial: pointer to the last triple within a chain 515 * 516 * Normally this function find the preferred place for block allocation, 517 * returns it. 518 * Because this is only used for non-extent files, we limit the block nr 519 * to 32 bits. 520 */ 521 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block, 522 Indirect *partial) 523 { 524 ext4_fsblk_t goal; 525 526 /* 527 * XXX need to get goal block from mballoc's data structures 528 */ 529 530 goal = ext4_find_near(inode, partial); 531 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 532 return goal; 533 } 534 535 /** 536 * ext4_blks_to_allocate: Look up the block map and count the number 537 * of direct blocks need to be allocated for the given branch. 538 * 539 * @branch: chain of indirect blocks 540 * @k: number of blocks need for indirect blocks 541 * @blks: number of data blocks to be mapped. 542 * @blocks_to_boundary: the offset in the indirect block 543 * 544 * return the total number of blocks to be allocate, including the 545 * direct and indirect blocks. 546 */ 547 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks, 548 int blocks_to_boundary) 549 { 550 unsigned int count = 0; 551 552 /* 553 * Simple case, [t,d]Indirect block(s) has not allocated yet 554 * then it's clear blocks on that path have not allocated 555 */ 556 if (k > 0) { 557 /* right now we don't handle cross boundary allocation */ 558 if (blks < blocks_to_boundary + 1) 559 count += blks; 560 else 561 count += blocks_to_boundary + 1; 562 return count; 563 } 564 565 count++; 566 while (count < blks && count <= blocks_to_boundary && 567 le32_to_cpu(*(branch[0].p + count)) == 0) { 568 count++; 569 } 570 return count; 571 } 572 573 /** 574 * ext4_alloc_blocks: multiple allocate blocks needed for a branch 575 * @indirect_blks: the number of blocks need to allocate for indirect 576 * blocks 577 * 578 * @new_blocks: on return it will store the new block numbers for 579 * the indirect blocks(if needed) and the first direct block, 580 * @blks: on return it will store the total number of allocated 581 * direct blocks 582 */ 583 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, 584 ext4_lblk_t iblock, ext4_fsblk_t goal, 585 int indirect_blks, int blks, 586 ext4_fsblk_t new_blocks[4], int *err) 587 { 588 struct ext4_allocation_request ar; 589 int target, i; 590 unsigned long count = 0, blk_allocated = 0; 591 int index = 0; 592 ext4_fsblk_t current_block = 0; 593 int ret = 0; 594 595 /* 596 * Here we try to allocate the requested multiple blocks at once, 597 * on a best-effort basis. 598 * To build a branch, we should allocate blocks for 599 * the indirect blocks(if not allocated yet), and at least 600 * the first direct block of this branch. That's the 601 * minimum number of blocks need to allocate(required) 602 */ 603 /* first we try to allocate the indirect blocks */ 604 target = indirect_blks; 605 while (target > 0) { 606 count = target; 607 /* allocating blocks for indirect blocks and direct blocks */ 608 current_block = ext4_new_meta_blocks(handle, inode, 609 goal, &count, err); 610 if (*err) 611 goto failed_out; 612 613 if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) { 614 EXT4_ERROR_INODE(inode, 615 "current_block %llu + count %lu > %d!", 616 current_block, count, 617 EXT4_MAX_BLOCK_FILE_PHYS); 618 *err = -EIO; 619 goto failed_out; 620 } 621 622 target -= count; 623 /* allocate blocks for indirect blocks */ 624 while (index < indirect_blks && count) { 625 new_blocks[index++] = current_block++; 626 count--; 627 } 628 if (count > 0) { 629 /* 630 * save the new block number 631 * for the first direct block 632 */ 633 new_blocks[index] = current_block; 634 printk(KERN_INFO "%s returned more blocks than " 635 "requested\n", __func__); 636 WARN_ON(1); 637 break; 638 } 639 } 640 641 target = blks - count ; 642 blk_allocated = count; 643 if (!target) 644 goto allocated; 645 /* Now allocate data blocks */ 646 memset(&ar, 0, sizeof(ar)); 647 ar.inode = inode; 648 ar.goal = goal; 649 ar.len = target; 650 ar.logical = iblock; 651 if (S_ISREG(inode->i_mode)) 652 /* enable in-core preallocation only for regular files */ 653 ar.flags = EXT4_MB_HINT_DATA; 654 655 current_block = ext4_mb_new_blocks(handle, &ar, err); 656 if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) { 657 EXT4_ERROR_INODE(inode, 658 "current_block %llu + ar.len %d > %d!", 659 current_block, ar.len, 660 EXT4_MAX_BLOCK_FILE_PHYS); 661 *err = -EIO; 662 goto failed_out; 663 } 664 665 if (*err && (target == blks)) { 666 /* 667 * if the allocation failed and we didn't allocate 668 * any blocks before 669 */ 670 goto failed_out; 671 } 672 if (!*err) { 673 if (target == blks) { 674 /* 675 * save the new block number 676 * for the first direct block 677 */ 678 new_blocks[index] = current_block; 679 } 680 blk_allocated += ar.len; 681 } 682 allocated: 683 /* total number of blocks allocated for direct blocks */ 684 ret = blk_allocated; 685 *err = 0; 686 return ret; 687 failed_out: 688 for (i = 0; i < index; i++) 689 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0); 690 return ret; 691 } 692 693 /** 694 * ext4_alloc_branch - allocate and set up a chain of blocks. 695 * @inode: owner 696 * @indirect_blks: number of allocated indirect blocks 697 * @blks: number of allocated direct blocks 698 * @offsets: offsets (in the blocks) to store the pointers to next. 699 * @branch: place to store the chain in. 700 * 701 * This function allocates blocks, zeroes out all but the last one, 702 * links them into chain and (if we are synchronous) writes them to disk. 703 * In other words, it prepares a branch that can be spliced onto the 704 * inode. It stores the information about that chain in the branch[], in 705 * the same format as ext4_get_branch() would do. We are calling it after 706 * we had read the existing part of chain and partial points to the last 707 * triple of that (one with zero ->key). Upon the exit we have the same 708 * picture as after the successful ext4_get_block(), except that in one 709 * place chain is disconnected - *branch->p is still zero (we did not 710 * set the last link), but branch->key contains the number that should 711 * be placed into *branch->p to fill that gap. 712 * 713 * If allocation fails we free all blocks we've allocated (and forget 714 * their buffer_heads) and return the error value the from failed 715 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain 716 * as described above and return 0. 717 */ 718 static int ext4_alloc_branch(handle_t *handle, struct inode *inode, 719 ext4_lblk_t iblock, int indirect_blks, 720 int *blks, ext4_fsblk_t goal, 721 ext4_lblk_t *offsets, Indirect *branch) 722 { 723 int blocksize = inode->i_sb->s_blocksize; 724 int i, n = 0; 725 int err = 0; 726 struct buffer_head *bh; 727 int num; 728 ext4_fsblk_t new_blocks[4]; 729 ext4_fsblk_t current_block; 730 731 num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks, 732 *blks, new_blocks, &err); 733 if (err) 734 return err; 735 736 branch[0].key = cpu_to_le32(new_blocks[0]); 737 /* 738 * metadata blocks and data blocks are allocated. 739 */ 740 for (n = 1; n <= indirect_blks; n++) { 741 /* 742 * Get buffer_head for parent block, zero it out 743 * and set the pointer to new one, then send 744 * parent to disk. 745 */ 746 bh = sb_getblk(inode->i_sb, new_blocks[n-1]); 747 branch[n].bh = bh; 748 lock_buffer(bh); 749 BUFFER_TRACE(bh, "call get_create_access"); 750 err = ext4_journal_get_create_access(handle, bh); 751 if (err) { 752 /* Don't brelse(bh) here; it's done in 753 * ext4_journal_forget() below */ 754 unlock_buffer(bh); 755 goto failed; 756 } 757 758 memset(bh->b_data, 0, blocksize); 759 branch[n].p = (__le32 *) bh->b_data + offsets[n]; 760 branch[n].key = cpu_to_le32(new_blocks[n]); 761 *branch[n].p = branch[n].key; 762 if (n == indirect_blks) { 763 current_block = new_blocks[n]; 764 /* 765 * End of chain, update the last new metablock of 766 * the chain to point to the new allocated 767 * data blocks numbers 768 */ 769 for (i = 1; i < num; i++) 770 *(branch[n].p + i) = cpu_to_le32(++current_block); 771 } 772 BUFFER_TRACE(bh, "marking uptodate"); 773 set_buffer_uptodate(bh); 774 unlock_buffer(bh); 775 776 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); 777 err = ext4_handle_dirty_metadata(handle, inode, bh); 778 if (err) 779 goto failed; 780 } 781 *blks = num; 782 return err; 783 failed: 784 /* Allocation failed, free what we already allocated */ 785 ext4_free_blocks(handle, inode, 0, new_blocks[0], 1, 0); 786 for (i = 1; i <= n ; i++) { 787 /* 788 * branch[i].bh is newly allocated, so there is no 789 * need to revoke the block, which is why we don't 790 * need to set EXT4_FREE_BLOCKS_METADATA. 791 */ 792 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 793 EXT4_FREE_BLOCKS_FORGET); 794 } 795 for (i = n+1; i < indirect_blks; i++) 796 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0); 797 798 ext4_free_blocks(handle, inode, 0, new_blocks[i], num, 0); 799 800 return err; 801 } 802 803 /** 804 * ext4_splice_branch - splice the allocated branch onto inode. 805 * @inode: owner 806 * @block: (logical) number of block we are adding 807 * @chain: chain of indirect blocks (with a missing link - see 808 * ext4_alloc_branch) 809 * @where: location of missing link 810 * @num: number of indirect blocks we are adding 811 * @blks: number of direct blocks we are adding 812 * 813 * This function fills the missing link and does all housekeeping needed in 814 * inode (->i_blocks, etc.). In case of success we end up with the full 815 * chain to new block and return 0. 816 */ 817 static int ext4_splice_branch(handle_t *handle, struct inode *inode, 818 ext4_lblk_t block, Indirect *where, int num, 819 int blks) 820 { 821 int i; 822 int err = 0; 823 ext4_fsblk_t current_block; 824 825 /* 826 * If we're splicing into a [td]indirect block (as opposed to the 827 * inode) then we need to get write access to the [td]indirect block 828 * before the splice. 829 */ 830 if (where->bh) { 831 BUFFER_TRACE(where->bh, "get_write_access"); 832 err = ext4_journal_get_write_access(handle, where->bh); 833 if (err) 834 goto err_out; 835 } 836 /* That's it */ 837 838 *where->p = where->key; 839 840 /* 841 * Update the host buffer_head or inode to point to more just allocated 842 * direct blocks blocks 843 */ 844 if (num == 0 && blks > 1) { 845 current_block = le32_to_cpu(where->key) + 1; 846 for (i = 1; i < blks; i++) 847 *(where->p + i) = cpu_to_le32(current_block++); 848 } 849 850 /* We are done with atomic stuff, now do the rest of housekeeping */ 851 /* had we spliced it onto indirect block? */ 852 if (where->bh) { 853 /* 854 * If we spliced it onto an indirect block, we haven't 855 * altered the inode. Note however that if it is being spliced 856 * onto an indirect block at the very end of the file (the 857 * file is growing) then we *will* alter the inode to reflect 858 * the new i_size. But that is not done here - it is done in 859 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode. 860 */ 861 jbd_debug(5, "splicing indirect only\n"); 862 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata"); 863 err = ext4_handle_dirty_metadata(handle, inode, where->bh); 864 if (err) 865 goto err_out; 866 } else { 867 /* 868 * OK, we spliced it into the inode itself on a direct block. 869 */ 870 ext4_mark_inode_dirty(handle, inode); 871 jbd_debug(5, "splicing direct\n"); 872 } 873 return err; 874 875 err_out: 876 for (i = 1; i <= num; i++) { 877 /* 878 * branch[i].bh is newly allocated, so there is no 879 * need to revoke the block, which is why we don't 880 * need to set EXT4_FREE_BLOCKS_METADATA. 881 */ 882 ext4_free_blocks(handle, inode, where[i].bh, 0, 1, 883 EXT4_FREE_BLOCKS_FORGET); 884 } 885 ext4_free_blocks(handle, inode, 0, le32_to_cpu(where[num].key), 886 blks, 0); 887 888 return err; 889 } 890 891 /* 892 * The ext4_ind_map_blocks() function handles non-extents inodes 893 * (i.e., using the traditional indirect/double-indirect i_blocks 894 * scheme) for ext4_map_blocks(). 895 * 896 * Allocation strategy is simple: if we have to allocate something, we will 897 * have to go the whole way to leaf. So let's do it before attaching anything 898 * to tree, set linkage between the newborn blocks, write them if sync is 899 * required, recheck the path, free and repeat if check fails, otherwise 900 * set the last missing link (that will protect us from any truncate-generated 901 * removals - all blocks on the path are immune now) and possibly force the 902 * write on the parent block. 903 * That has a nice additional property: no special recovery from the failed 904 * allocations is needed - we simply release blocks and do not touch anything 905 * reachable from inode. 906 * 907 * `handle' can be NULL if create == 0. 908 * 909 * return > 0, # of blocks mapped or allocated. 910 * return = 0, if plain lookup failed. 911 * return < 0, error case. 912 * 913 * The ext4_ind_get_blocks() function should be called with 914 * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem 915 * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or 916 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system 917 * blocks. 918 */ 919 static int ext4_ind_map_blocks(handle_t *handle, struct inode *inode, 920 struct ext4_map_blocks *map, 921 int flags) 922 { 923 int err = -EIO; 924 ext4_lblk_t offsets[4]; 925 Indirect chain[4]; 926 Indirect *partial; 927 ext4_fsblk_t goal; 928 int indirect_blks; 929 int blocks_to_boundary = 0; 930 int depth; 931 int count = 0; 932 ext4_fsblk_t first_block = 0; 933 934 J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))); 935 J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0); 936 depth = ext4_block_to_path(inode, map->m_lblk, offsets, 937 &blocks_to_boundary); 938 939 if (depth == 0) 940 goto out; 941 942 partial = ext4_get_branch(inode, depth, offsets, chain, &err); 943 944 /* Simplest case - block found, no allocation needed */ 945 if (!partial) { 946 first_block = le32_to_cpu(chain[depth - 1].key); 947 count++; 948 /*map more blocks*/ 949 while (count < map->m_len && count <= blocks_to_boundary) { 950 ext4_fsblk_t blk; 951 952 blk = le32_to_cpu(*(chain[depth-1].p + count)); 953 954 if (blk == first_block + count) 955 count++; 956 else 957 break; 958 } 959 goto got_it; 960 } 961 962 /* Next simple case - plain lookup or failed read of indirect block */ 963 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO) 964 goto cleanup; 965 966 /* 967 * Okay, we need to do block allocation. 968 */ 969 goal = ext4_find_goal(inode, map->m_lblk, partial); 970 971 /* the number of blocks need to allocate for [d,t]indirect blocks */ 972 indirect_blks = (chain + depth) - partial - 1; 973 974 /* 975 * Next look up the indirect map to count the totoal number of 976 * direct blocks to allocate for this branch. 977 */ 978 count = ext4_blks_to_allocate(partial, indirect_blks, 979 map->m_len, blocks_to_boundary); 980 /* 981 * Block out ext4_truncate while we alter the tree 982 */ 983 err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks, 984 &count, goal, 985 offsets + (partial - chain), partial); 986 987 /* 988 * The ext4_splice_branch call will free and forget any buffers 989 * on the new chain if there is a failure, but that risks using 990 * up transaction credits, especially for bitmaps where the 991 * credits cannot be returned. Can we handle this somehow? We 992 * may need to return -EAGAIN upwards in the worst case. --sct 993 */ 994 if (!err) 995 err = ext4_splice_branch(handle, inode, map->m_lblk, 996 partial, indirect_blks, count); 997 if (err) 998 goto cleanup; 999 1000 map->m_flags |= EXT4_MAP_NEW; 1001 1002 ext4_update_inode_fsync_trans(handle, inode, 1); 1003 got_it: 1004 map->m_flags |= EXT4_MAP_MAPPED; 1005 map->m_pblk = le32_to_cpu(chain[depth-1].key); 1006 map->m_len = count; 1007 if (count > blocks_to_boundary) 1008 map->m_flags |= EXT4_MAP_BOUNDARY; 1009 err = count; 1010 /* Clean up and exit */ 1011 partial = chain + depth - 1; /* the whole chain */ 1012 cleanup: 1013 while (partial > chain) { 1014 BUFFER_TRACE(partial->bh, "call brelse"); 1015 brelse(partial->bh); 1016 partial--; 1017 } 1018 out: 1019 return err; 1020 } 1021 1022 #ifdef CONFIG_QUOTA 1023 qsize_t *ext4_get_reserved_space(struct inode *inode) 1024 { 1025 return &EXT4_I(inode)->i_reserved_quota; 1026 } 1027 #endif 1028 1029 /* 1030 * Calculate the number of metadata blocks need to reserve 1031 * to allocate a new block at @lblocks for non extent file based file 1032 */ 1033 static int ext4_indirect_calc_metadata_amount(struct inode *inode, 1034 sector_t lblock) 1035 { 1036 struct ext4_inode_info *ei = EXT4_I(inode); 1037 sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1); 1038 int blk_bits; 1039 1040 if (lblock < EXT4_NDIR_BLOCKS) 1041 return 0; 1042 1043 lblock -= EXT4_NDIR_BLOCKS; 1044 1045 if (ei->i_da_metadata_calc_len && 1046 (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) { 1047 ei->i_da_metadata_calc_len++; 1048 return 0; 1049 } 1050 ei->i_da_metadata_calc_last_lblock = lblock & dind_mask; 1051 ei->i_da_metadata_calc_len = 1; 1052 blk_bits = order_base_2(lblock); 1053 return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1; 1054 } 1055 1056 /* 1057 * Calculate the number of metadata blocks need to reserve 1058 * to allocate a block located at @lblock 1059 */ 1060 static int ext4_calc_metadata_amount(struct inode *inode, sector_t lblock) 1061 { 1062 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) 1063 return ext4_ext_calc_metadata_amount(inode, lblock); 1064 1065 return ext4_indirect_calc_metadata_amount(inode, lblock); 1066 } 1067 1068 /* 1069 * Called with i_data_sem down, which is important since we can call 1070 * ext4_discard_preallocations() from here. 1071 */ 1072 void ext4_da_update_reserve_space(struct inode *inode, 1073 int used, int quota_claim) 1074 { 1075 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1076 struct ext4_inode_info *ei = EXT4_I(inode); 1077 1078 spin_lock(&ei->i_block_reservation_lock); 1079 trace_ext4_da_update_reserve_space(inode, used); 1080 if (unlikely(used > ei->i_reserved_data_blocks)) { 1081 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d " 1082 "with only %d reserved data blocks\n", 1083 __func__, inode->i_ino, used, 1084 ei->i_reserved_data_blocks); 1085 WARN_ON(1); 1086 used = ei->i_reserved_data_blocks; 1087 } 1088 1089 /* Update per-inode reservations */ 1090 ei->i_reserved_data_blocks -= used; 1091 ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks; 1092 percpu_counter_sub(&sbi->s_dirtyblocks_counter, 1093 used + ei->i_allocated_meta_blocks); 1094 ei->i_allocated_meta_blocks = 0; 1095 1096 if (ei->i_reserved_data_blocks == 0) { 1097 /* 1098 * We can release all of the reserved metadata blocks 1099 * only when we have written all of the delayed 1100 * allocation blocks. 1101 */ 1102 percpu_counter_sub(&sbi->s_dirtyblocks_counter, 1103 ei->i_reserved_meta_blocks); 1104 ei->i_reserved_meta_blocks = 0; 1105 ei->i_da_metadata_calc_len = 0; 1106 } 1107 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1108 1109 /* Update quota subsystem for data blocks */ 1110 if (quota_claim) 1111 dquot_claim_block(inode, used); 1112 else { 1113 /* 1114 * We did fallocate with an offset that is already delayed 1115 * allocated. So on delayed allocated writeback we should 1116 * not re-claim the quota for fallocated blocks. 1117 */ 1118 dquot_release_reservation_block(inode, used); 1119 } 1120 1121 /* 1122 * If we have done all the pending block allocations and if 1123 * there aren't any writers on the inode, we can discard the 1124 * inode's preallocations. 1125 */ 1126 if ((ei->i_reserved_data_blocks == 0) && 1127 (atomic_read(&inode->i_writecount) == 0)) 1128 ext4_discard_preallocations(inode); 1129 } 1130 1131 static int check_block_validity(struct inode *inode, const char *func, 1132 struct ext4_map_blocks *map) 1133 { 1134 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk, 1135 map->m_len)) { 1136 ext4_error_inode(func, inode, 1137 "lblock %lu mapped to illegal pblock %llu " 1138 "(length %d)", (unsigned long) map->m_lblk, 1139 map->m_pblk, map->m_len); 1140 return -EIO; 1141 } 1142 return 0; 1143 } 1144 1145 /* 1146 * Return the number of contiguous dirty pages in a given inode 1147 * starting at page frame idx. 1148 */ 1149 static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx, 1150 unsigned int max_pages) 1151 { 1152 struct address_space *mapping = inode->i_mapping; 1153 pgoff_t index; 1154 struct pagevec pvec; 1155 pgoff_t num = 0; 1156 int i, nr_pages, done = 0; 1157 1158 if (max_pages == 0) 1159 return 0; 1160 pagevec_init(&pvec, 0); 1161 while (!done) { 1162 index = idx; 1163 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, 1164 PAGECACHE_TAG_DIRTY, 1165 (pgoff_t)PAGEVEC_SIZE); 1166 if (nr_pages == 0) 1167 break; 1168 for (i = 0; i < nr_pages; i++) { 1169 struct page *page = pvec.pages[i]; 1170 struct buffer_head *bh, *head; 1171 1172 lock_page(page); 1173 if (unlikely(page->mapping != mapping) || 1174 !PageDirty(page) || 1175 PageWriteback(page) || 1176 page->index != idx) { 1177 done = 1; 1178 unlock_page(page); 1179 break; 1180 } 1181 if (page_has_buffers(page)) { 1182 bh = head = page_buffers(page); 1183 do { 1184 if (!buffer_delay(bh) && 1185 !buffer_unwritten(bh)) 1186 done = 1; 1187 bh = bh->b_this_page; 1188 } while (!done && (bh != head)); 1189 } 1190 unlock_page(page); 1191 if (done) 1192 break; 1193 idx++; 1194 num++; 1195 if (num >= max_pages) 1196 break; 1197 } 1198 pagevec_release(&pvec); 1199 } 1200 return num; 1201 } 1202 1203 /* 1204 * The ext4_map_blocks() function tries to look up the requested blocks, 1205 * and returns if the blocks are already mapped. 1206 * 1207 * Otherwise it takes the write lock of the i_data_sem and allocate blocks 1208 * and store the allocated blocks in the result buffer head and mark it 1209 * mapped. 1210 * 1211 * If file type is extents based, it will call ext4_ext_map_blocks(), 1212 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping 1213 * based files 1214 * 1215 * On success, it returns the number of blocks being mapped or allocate. 1216 * if create==0 and the blocks are pre-allocated and uninitialized block, 1217 * the result buffer head is unmapped. If the create ==1, it will make sure 1218 * the buffer head is mapped. 1219 * 1220 * It returns 0 if plain look up failed (blocks have not been allocated), in 1221 * that casem, buffer head is unmapped 1222 * 1223 * It returns the error in case of allocation failure. 1224 */ 1225 int ext4_map_blocks(handle_t *handle, struct inode *inode, 1226 struct ext4_map_blocks *map, int flags) 1227 { 1228 int retval; 1229 1230 map->m_flags = 0; 1231 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u," 1232 "logical block %lu\n", inode->i_ino, flags, map->m_len, 1233 (unsigned long) map->m_lblk); 1234 /* 1235 * Try to see if we can get the block without requesting a new 1236 * file system block. 1237 */ 1238 down_read((&EXT4_I(inode)->i_data_sem)); 1239 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { 1240 retval = ext4_ext_map_blocks(handle, inode, map, 0); 1241 } else { 1242 retval = ext4_ind_map_blocks(handle, inode, map, 0); 1243 } 1244 up_read((&EXT4_I(inode)->i_data_sem)); 1245 1246 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { 1247 int ret = check_block_validity(inode, __func__, map); 1248 if (ret != 0) 1249 return ret; 1250 } 1251 1252 /* If it is only a block(s) look up */ 1253 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) 1254 return retval; 1255 1256 /* 1257 * Returns if the blocks have already allocated 1258 * 1259 * Note that if blocks have been preallocated 1260 * ext4_ext_get_block() returns th create = 0 1261 * with buffer head unmapped. 1262 */ 1263 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) 1264 return retval; 1265 1266 /* 1267 * When we call get_blocks without the create flag, the 1268 * BH_Unwritten flag could have gotten set if the blocks 1269 * requested were part of a uninitialized extent. We need to 1270 * clear this flag now that we are committed to convert all or 1271 * part of the uninitialized extent to be an initialized 1272 * extent. This is because we need to avoid the combination 1273 * of BH_Unwritten and BH_Mapped flags being simultaneously 1274 * set on the buffer_head. 1275 */ 1276 map->m_flags &= ~EXT4_MAP_UNWRITTEN; 1277 1278 /* 1279 * New blocks allocate and/or writing to uninitialized extent 1280 * will possibly result in updating i_data, so we take 1281 * the write lock of i_data_sem, and call get_blocks() 1282 * with create == 1 flag. 1283 */ 1284 down_write((&EXT4_I(inode)->i_data_sem)); 1285 1286 /* 1287 * if the caller is from delayed allocation writeout path 1288 * we have already reserved fs blocks for allocation 1289 * let the underlying get_block() function know to 1290 * avoid double accounting 1291 */ 1292 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) 1293 EXT4_I(inode)->i_delalloc_reserved_flag = 1; 1294 /* 1295 * We need to check for EXT4 here because migrate 1296 * could have changed the inode type in between 1297 */ 1298 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { 1299 retval = ext4_ext_map_blocks(handle, inode, map, flags); 1300 } else { 1301 retval = ext4_ind_map_blocks(handle, inode, map, flags); 1302 1303 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) { 1304 /* 1305 * We allocated new blocks which will result in 1306 * i_data's format changing. Force the migrate 1307 * to fail by clearing migrate flags 1308 */ 1309 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE); 1310 } 1311 1312 /* 1313 * Update reserved blocks/metadata blocks after successful 1314 * block allocation which had been deferred till now. We don't 1315 * support fallocate for non extent files. So we can update 1316 * reserve space here. 1317 */ 1318 if ((retval > 0) && 1319 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)) 1320 ext4_da_update_reserve_space(inode, retval, 1); 1321 } 1322 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) 1323 EXT4_I(inode)->i_delalloc_reserved_flag = 0; 1324 1325 up_write((&EXT4_I(inode)->i_data_sem)); 1326 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { 1327 int ret = check_block_validity(inode, 1328 "ext4_map_blocks_after_alloc", 1329 map); 1330 if (ret != 0) 1331 return ret; 1332 } 1333 return retval; 1334 } 1335 1336 /* Maximum number of blocks we map for direct IO at once. */ 1337 #define DIO_MAX_BLOCKS 4096 1338 1339 static int _ext4_get_block(struct inode *inode, sector_t iblock, 1340 struct buffer_head *bh, int flags) 1341 { 1342 handle_t *handle = ext4_journal_current_handle(); 1343 struct ext4_map_blocks map; 1344 int ret = 0, started = 0; 1345 int dio_credits; 1346 1347 map.m_lblk = iblock; 1348 map.m_len = bh->b_size >> inode->i_blkbits; 1349 1350 if (flags && !handle) { 1351 /* Direct IO write... */ 1352 if (map.m_len > DIO_MAX_BLOCKS) 1353 map.m_len = DIO_MAX_BLOCKS; 1354 dio_credits = ext4_chunk_trans_blocks(inode, map.m_len); 1355 handle = ext4_journal_start(inode, dio_credits); 1356 if (IS_ERR(handle)) { 1357 ret = PTR_ERR(handle); 1358 return ret; 1359 } 1360 started = 1; 1361 } 1362 1363 ret = ext4_map_blocks(handle, inode, &map, flags); 1364 if (ret > 0) { 1365 map_bh(bh, inode->i_sb, map.m_pblk); 1366 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; 1367 bh->b_size = inode->i_sb->s_blocksize * map.m_len; 1368 ret = 0; 1369 } 1370 if (started) 1371 ext4_journal_stop(handle); 1372 return ret; 1373 } 1374 1375 int ext4_get_block(struct inode *inode, sector_t iblock, 1376 struct buffer_head *bh, int create) 1377 { 1378 return _ext4_get_block(inode, iblock, bh, 1379 create ? EXT4_GET_BLOCKS_CREATE : 0); 1380 } 1381 1382 /* 1383 * `handle' can be NULL if create is zero 1384 */ 1385 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode, 1386 ext4_lblk_t block, int create, int *errp) 1387 { 1388 struct ext4_map_blocks map; 1389 struct buffer_head *bh; 1390 int fatal = 0, err; 1391 1392 J_ASSERT(handle != NULL || create == 0); 1393 1394 map.m_lblk = block; 1395 map.m_len = 1; 1396 err = ext4_map_blocks(handle, inode, &map, 1397 create ? EXT4_GET_BLOCKS_CREATE : 0); 1398 1399 if (err < 0) 1400 *errp = err; 1401 if (err <= 0) 1402 return NULL; 1403 *errp = 0; 1404 1405 bh = sb_getblk(inode->i_sb, map.m_pblk); 1406 if (!bh) { 1407 *errp = -EIO; 1408 return NULL; 1409 } 1410 if (map.m_flags & EXT4_MAP_NEW) { 1411 J_ASSERT(create != 0); 1412 J_ASSERT(handle != NULL); 1413 1414 /* 1415 * Now that we do not always journal data, we should 1416 * keep in mind whether this should always journal the 1417 * new buffer as metadata. For now, regular file 1418 * writes use ext4_get_block instead, so it's not a 1419 * problem. 1420 */ 1421 lock_buffer(bh); 1422 BUFFER_TRACE(bh, "call get_create_access"); 1423 fatal = ext4_journal_get_create_access(handle, bh); 1424 if (!fatal && !buffer_uptodate(bh)) { 1425 memset(bh->b_data, 0, inode->i_sb->s_blocksize); 1426 set_buffer_uptodate(bh); 1427 } 1428 unlock_buffer(bh); 1429 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); 1430 err = ext4_handle_dirty_metadata(handle, inode, bh); 1431 if (!fatal) 1432 fatal = err; 1433 } else { 1434 BUFFER_TRACE(bh, "not a new buffer"); 1435 } 1436 if (fatal) { 1437 *errp = fatal; 1438 brelse(bh); 1439 bh = NULL; 1440 } 1441 return bh; 1442 } 1443 1444 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode, 1445 ext4_lblk_t block, int create, int *err) 1446 { 1447 struct buffer_head *bh; 1448 1449 bh = ext4_getblk(handle, inode, block, create, err); 1450 if (!bh) 1451 return bh; 1452 if (buffer_uptodate(bh)) 1453 return bh; 1454 ll_rw_block(READ_META, 1, &bh); 1455 wait_on_buffer(bh); 1456 if (buffer_uptodate(bh)) 1457 return bh; 1458 put_bh(bh); 1459 *err = -EIO; 1460 return NULL; 1461 } 1462 1463 static int walk_page_buffers(handle_t *handle, 1464 struct buffer_head *head, 1465 unsigned from, 1466 unsigned to, 1467 int *partial, 1468 int (*fn)(handle_t *handle, 1469 struct buffer_head *bh)) 1470 { 1471 struct buffer_head *bh; 1472 unsigned block_start, block_end; 1473 unsigned blocksize = head->b_size; 1474 int err, ret = 0; 1475 struct buffer_head *next; 1476 1477 for (bh = head, block_start = 0; 1478 ret == 0 && (bh != head || !block_start); 1479 block_start = block_end, bh = next) { 1480 next = bh->b_this_page; 1481 block_end = block_start + blocksize; 1482 if (block_end <= from || block_start >= to) { 1483 if (partial && !buffer_uptodate(bh)) 1484 *partial = 1; 1485 continue; 1486 } 1487 err = (*fn)(handle, bh); 1488 if (!ret) 1489 ret = err; 1490 } 1491 return ret; 1492 } 1493 1494 /* 1495 * To preserve ordering, it is essential that the hole instantiation and 1496 * the data write be encapsulated in a single transaction. We cannot 1497 * close off a transaction and start a new one between the ext4_get_block() 1498 * and the commit_write(). So doing the jbd2_journal_start at the start of 1499 * prepare_write() is the right place. 1500 * 1501 * Also, this function can nest inside ext4_writepage() -> 1502 * block_write_full_page(). In that case, we *know* that ext4_writepage() 1503 * has generated enough buffer credits to do the whole page. So we won't 1504 * block on the journal in that case, which is good, because the caller may 1505 * be PF_MEMALLOC. 1506 * 1507 * By accident, ext4 can be reentered when a transaction is open via 1508 * quota file writes. If we were to commit the transaction while thus 1509 * reentered, there can be a deadlock - we would be holding a quota 1510 * lock, and the commit would never complete if another thread had a 1511 * transaction open and was blocking on the quota lock - a ranking 1512 * violation. 1513 * 1514 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start 1515 * will _not_ run commit under these circumstances because handle->h_ref 1516 * is elevated. We'll still have enough credits for the tiny quotafile 1517 * write. 1518 */ 1519 static int do_journal_get_write_access(handle_t *handle, 1520 struct buffer_head *bh) 1521 { 1522 if (!buffer_mapped(bh) || buffer_freed(bh)) 1523 return 0; 1524 return ext4_journal_get_write_access(handle, bh); 1525 } 1526 1527 /* 1528 * Truncate blocks that were not used by write. We have to truncate the 1529 * pagecache as well so that corresponding buffers get properly unmapped. 1530 */ 1531 static void ext4_truncate_failed_write(struct inode *inode) 1532 { 1533 truncate_inode_pages(inode->i_mapping, inode->i_size); 1534 ext4_truncate(inode); 1535 } 1536 1537 static int ext4_get_block_write(struct inode *inode, sector_t iblock, 1538 struct buffer_head *bh_result, int create); 1539 static int ext4_write_begin(struct file *file, struct address_space *mapping, 1540 loff_t pos, unsigned len, unsigned flags, 1541 struct page **pagep, void **fsdata) 1542 { 1543 struct inode *inode = mapping->host; 1544 int ret, needed_blocks; 1545 handle_t *handle; 1546 int retries = 0; 1547 struct page *page; 1548 pgoff_t index; 1549 unsigned from, to; 1550 1551 trace_ext4_write_begin(inode, pos, len, flags); 1552 /* 1553 * Reserve one block more for addition to orphan list in case 1554 * we allocate blocks but write fails for some reason 1555 */ 1556 needed_blocks = ext4_writepage_trans_blocks(inode) + 1; 1557 index = pos >> PAGE_CACHE_SHIFT; 1558 from = pos & (PAGE_CACHE_SIZE - 1); 1559 to = from + len; 1560 1561 retry: 1562 handle = ext4_journal_start(inode, needed_blocks); 1563 if (IS_ERR(handle)) { 1564 ret = PTR_ERR(handle); 1565 goto out; 1566 } 1567 1568 /* We cannot recurse into the filesystem as the transaction is already 1569 * started */ 1570 flags |= AOP_FLAG_NOFS; 1571 1572 page = grab_cache_page_write_begin(mapping, index, flags); 1573 if (!page) { 1574 ext4_journal_stop(handle); 1575 ret = -ENOMEM; 1576 goto out; 1577 } 1578 *pagep = page; 1579 1580 if (ext4_should_dioread_nolock(inode)) 1581 ret = block_write_begin(file, mapping, pos, len, flags, pagep, 1582 fsdata, ext4_get_block_write); 1583 else 1584 ret = block_write_begin(file, mapping, pos, len, flags, pagep, 1585 fsdata, ext4_get_block); 1586 1587 if (!ret && ext4_should_journal_data(inode)) { 1588 ret = walk_page_buffers(handle, page_buffers(page), 1589 from, to, NULL, do_journal_get_write_access); 1590 } 1591 1592 if (ret) { 1593 unlock_page(page); 1594 page_cache_release(page); 1595 /* 1596 * block_write_begin may have instantiated a few blocks 1597 * outside i_size. Trim these off again. Don't need 1598 * i_size_read because we hold i_mutex. 1599 * 1600 * Add inode to orphan list in case we crash before 1601 * truncate finishes 1602 */ 1603 if (pos + len > inode->i_size && ext4_can_truncate(inode)) 1604 ext4_orphan_add(handle, inode); 1605 1606 ext4_journal_stop(handle); 1607 if (pos + len > inode->i_size) { 1608 ext4_truncate_failed_write(inode); 1609 /* 1610 * If truncate failed early the inode might 1611 * still be on the orphan list; we need to 1612 * make sure the inode is removed from the 1613 * orphan list in that case. 1614 */ 1615 if (inode->i_nlink) 1616 ext4_orphan_del(NULL, inode); 1617 } 1618 } 1619 1620 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) 1621 goto retry; 1622 out: 1623 return ret; 1624 } 1625 1626 /* For write_end() in data=journal mode */ 1627 static int write_end_fn(handle_t *handle, struct buffer_head *bh) 1628 { 1629 if (!buffer_mapped(bh) || buffer_freed(bh)) 1630 return 0; 1631 set_buffer_uptodate(bh); 1632 return ext4_handle_dirty_metadata(handle, NULL, bh); 1633 } 1634 1635 static int ext4_generic_write_end(struct file *file, 1636 struct address_space *mapping, 1637 loff_t pos, unsigned len, unsigned copied, 1638 struct page *page, void *fsdata) 1639 { 1640 int i_size_changed = 0; 1641 struct inode *inode = mapping->host; 1642 handle_t *handle = ext4_journal_current_handle(); 1643 1644 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); 1645 1646 /* 1647 * No need to use i_size_read() here, the i_size 1648 * cannot change under us because we hold i_mutex. 1649 * 1650 * But it's important to update i_size while still holding page lock: 1651 * page writeout could otherwise come in and zero beyond i_size. 1652 */ 1653 if (pos + copied > inode->i_size) { 1654 i_size_write(inode, pos + copied); 1655 i_size_changed = 1; 1656 } 1657 1658 if (pos + copied > EXT4_I(inode)->i_disksize) { 1659 /* We need to mark inode dirty even if 1660 * new_i_size is less that inode->i_size 1661 * bu greater than i_disksize.(hint delalloc) 1662 */ 1663 ext4_update_i_disksize(inode, (pos + copied)); 1664 i_size_changed = 1; 1665 } 1666 unlock_page(page); 1667 page_cache_release(page); 1668 1669 /* 1670 * Don't mark the inode dirty under page lock. First, it unnecessarily 1671 * makes the holding time of page lock longer. Second, it forces lock 1672 * ordering of page lock and transaction start for journaling 1673 * filesystems. 1674 */ 1675 if (i_size_changed) 1676 ext4_mark_inode_dirty(handle, inode); 1677 1678 return copied; 1679 } 1680 1681 /* 1682 * We need to pick up the new inode size which generic_commit_write gave us 1683 * `file' can be NULL - eg, when called from page_symlink(). 1684 * 1685 * ext4 never places buffers on inode->i_mapping->private_list. metadata 1686 * buffers are managed internally. 1687 */ 1688 static int ext4_ordered_write_end(struct file *file, 1689 struct address_space *mapping, 1690 loff_t pos, unsigned len, unsigned copied, 1691 struct page *page, void *fsdata) 1692 { 1693 handle_t *handle = ext4_journal_current_handle(); 1694 struct inode *inode = mapping->host; 1695 int ret = 0, ret2; 1696 1697 trace_ext4_ordered_write_end(inode, pos, len, copied); 1698 ret = ext4_jbd2_file_inode(handle, inode); 1699 1700 if (ret == 0) { 1701 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, 1702 page, fsdata); 1703 copied = ret2; 1704 if (pos + len > inode->i_size && ext4_can_truncate(inode)) 1705 /* if we have allocated more blocks and copied 1706 * less. We will have blocks allocated outside 1707 * inode->i_size. So truncate them 1708 */ 1709 ext4_orphan_add(handle, inode); 1710 if (ret2 < 0) 1711 ret = ret2; 1712 } 1713 ret2 = ext4_journal_stop(handle); 1714 if (!ret) 1715 ret = ret2; 1716 1717 if (pos + len > inode->i_size) { 1718 ext4_truncate_failed_write(inode); 1719 /* 1720 * If truncate failed early the inode might still be 1721 * on the orphan list; we need to make sure the inode 1722 * is removed from the orphan list in that case. 1723 */ 1724 if (inode->i_nlink) 1725 ext4_orphan_del(NULL, inode); 1726 } 1727 1728 1729 return ret ? ret : copied; 1730 } 1731 1732 static int ext4_writeback_write_end(struct file *file, 1733 struct address_space *mapping, 1734 loff_t pos, unsigned len, unsigned copied, 1735 struct page *page, void *fsdata) 1736 { 1737 handle_t *handle = ext4_journal_current_handle(); 1738 struct inode *inode = mapping->host; 1739 int ret = 0, ret2; 1740 1741 trace_ext4_writeback_write_end(inode, pos, len, copied); 1742 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, 1743 page, fsdata); 1744 copied = ret2; 1745 if (pos + len > inode->i_size && ext4_can_truncate(inode)) 1746 /* if we have allocated more blocks and copied 1747 * less. We will have blocks allocated outside 1748 * inode->i_size. So truncate them 1749 */ 1750 ext4_orphan_add(handle, inode); 1751 1752 if (ret2 < 0) 1753 ret = ret2; 1754 1755 ret2 = ext4_journal_stop(handle); 1756 if (!ret) 1757 ret = ret2; 1758 1759 if (pos + len > inode->i_size) { 1760 ext4_truncate_failed_write(inode); 1761 /* 1762 * If truncate failed early the inode might still be 1763 * on the orphan list; we need to make sure the inode 1764 * is removed from the orphan list in that case. 1765 */ 1766 if (inode->i_nlink) 1767 ext4_orphan_del(NULL, inode); 1768 } 1769 1770 return ret ? ret : copied; 1771 } 1772 1773 static int ext4_journalled_write_end(struct file *file, 1774 struct address_space *mapping, 1775 loff_t pos, unsigned len, unsigned copied, 1776 struct page *page, void *fsdata) 1777 { 1778 handle_t *handle = ext4_journal_current_handle(); 1779 struct inode *inode = mapping->host; 1780 int ret = 0, ret2; 1781 int partial = 0; 1782 unsigned from, to; 1783 loff_t new_i_size; 1784 1785 trace_ext4_journalled_write_end(inode, pos, len, copied); 1786 from = pos & (PAGE_CACHE_SIZE - 1); 1787 to = from + len; 1788 1789 if (copied < len) { 1790 if (!PageUptodate(page)) 1791 copied = 0; 1792 page_zero_new_buffers(page, from+copied, to); 1793 } 1794 1795 ret = walk_page_buffers(handle, page_buffers(page), from, 1796 to, &partial, write_end_fn); 1797 if (!partial) 1798 SetPageUptodate(page); 1799 new_i_size = pos + copied; 1800 if (new_i_size > inode->i_size) 1801 i_size_write(inode, pos+copied); 1802 ext4_set_inode_state(inode, EXT4_STATE_JDATA); 1803 if (new_i_size > EXT4_I(inode)->i_disksize) { 1804 ext4_update_i_disksize(inode, new_i_size); 1805 ret2 = ext4_mark_inode_dirty(handle, inode); 1806 if (!ret) 1807 ret = ret2; 1808 } 1809 1810 unlock_page(page); 1811 page_cache_release(page); 1812 if (pos + len > inode->i_size && ext4_can_truncate(inode)) 1813 /* if we have allocated more blocks and copied 1814 * less. We will have blocks allocated outside 1815 * inode->i_size. So truncate them 1816 */ 1817 ext4_orphan_add(handle, inode); 1818 1819 ret2 = ext4_journal_stop(handle); 1820 if (!ret) 1821 ret = ret2; 1822 if (pos + len > inode->i_size) { 1823 ext4_truncate_failed_write(inode); 1824 /* 1825 * If truncate failed early the inode might still be 1826 * on the orphan list; we need to make sure the inode 1827 * is removed from the orphan list in that case. 1828 */ 1829 if (inode->i_nlink) 1830 ext4_orphan_del(NULL, inode); 1831 } 1832 1833 return ret ? ret : copied; 1834 } 1835 1836 /* 1837 * Reserve a single block located at lblock 1838 */ 1839 static int ext4_da_reserve_space(struct inode *inode, sector_t lblock) 1840 { 1841 int retries = 0; 1842 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1843 struct ext4_inode_info *ei = EXT4_I(inode); 1844 unsigned long md_needed; 1845 int ret; 1846 1847 /* 1848 * recalculate the amount of metadata blocks to reserve 1849 * in order to allocate nrblocks 1850 * worse case is one extent per block 1851 */ 1852 repeat: 1853 spin_lock(&ei->i_block_reservation_lock); 1854 md_needed = ext4_calc_metadata_amount(inode, lblock); 1855 trace_ext4_da_reserve_space(inode, md_needed); 1856 spin_unlock(&ei->i_block_reservation_lock); 1857 1858 /* 1859 * We will charge metadata quota at writeout time; this saves 1860 * us from metadata over-estimation, though we may go over by 1861 * a small amount in the end. Here we just reserve for data. 1862 */ 1863 ret = dquot_reserve_block(inode, 1); 1864 if (ret) 1865 return ret; 1866 /* 1867 * We do still charge estimated metadata to the sb though; 1868 * we cannot afford to run out of free blocks. 1869 */ 1870 if (ext4_claim_free_blocks(sbi, md_needed + 1)) { 1871 dquot_release_reservation_block(inode, 1); 1872 if (ext4_should_retry_alloc(inode->i_sb, &retries)) { 1873 yield(); 1874 goto repeat; 1875 } 1876 return -ENOSPC; 1877 } 1878 spin_lock(&ei->i_block_reservation_lock); 1879 ei->i_reserved_data_blocks++; 1880 ei->i_reserved_meta_blocks += md_needed; 1881 spin_unlock(&ei->i_block_reservation_lock); 1882 1883 return 0; /* success */ 1884 } 1885 1886 static void ext4_da_release_space(struct inode *inode, int to_free) 1887 { 1888 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 1889 struct ext4_inode_info *ei = EXT4_I(inode); 1890 1891 if (!to_free) 1892 return; /* Nothing to release, exit */ 1893 1894 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 1895 1896 trace_ext4_da_release_space(inode, to_free); 1897 if (unlikely(to_free > ei->i_reserved_data_blocks)) { 1898 /* 1899 * if there aren't enough reserved blocks, then the 1900 * counter is messed up somewhere. Since this 1901 * function is called from invalidate page, it's 1902 * harmless to return without any action. 1903 */ 1904 ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: " 1905 "ino %lu, to_free %d with only %d reserved " 1906 "data blocks\n", inode->i_ino, to_free, 1907 ei->i_reserved_data_blocks); 1908 WARN_ON(1); 1909 to_free = ei->i_reserved_data_blocks; 1910 } 1911 ei->i_reserved_data_blocks -= to_free; 1912 1913 if (ei->i_reserved_data_blocks == 0) { 1914 /* 1915 * We can release all of the reserved metadata blocks 1916 * only when we have written all of the delayed 1917 * allocation blocks. 1918 */ 1919 percpu_counter_sub(&sbi->s_dirtyblocks_counter, 1920 ei->i_reserved_meta_blocks); 1921 ei->i_reserved_meta_blocks = 0; 1922 ei->i_da_metadata_calc_len = 0; 1923 } 1924 1925 /* update fs dirty data blocks counter */ 1926 percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free); 1927 1928 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 1929 1930 dquot_release_reservation_block(inode, to_free); 1931 } 1932 1933 static void ext4_da_page_release_reservation(struct page *page, 1934 unsigned long offset) 1935 { 1936 int to_release = 0; 1937 struct buffer_head *head, *bh; 1938 unsigned int curr_off = 0; 1939 1940 head = page_buffers(page); 1941 bh = head; 1942 do { 1943 unsigned int next_off = curr_off + bh->b_size; 1944 1945 if ((offset <= curr_off) && (buffer_delay(bh))) { 1946 to_release++; 1947 clear_buffer_delay(bh); 1948 } 1949 curr_off = next_off; 1950 } while ((bh = bh->b_this_page) != head); 1951 ext4_da_release_space(page->mapping->host, to_release); 1952 } 1953 1954 /* 1955 * Delayed allocation stuff 1956 */ 1957 1958 /* 1959 * mpage_da_submit_io - walks through extent of pages and try to write 1960 * them with writepage() call back 1961 * 1962 * @mpd->inode: inode 1963 * @mpd->first_page: first page of the extent 1964 * @mpd->next_page: page after the last page of the extent 1965 * 1966 * By the time mpage_da_submit_io() is called we expect all blocks 1967 * to be allocated. this may be wrong if allocation failed. 1968 * 1969 * As pages are already locked by write_cache_pages(), we can't use it 1970 */ 1971 static int mpage_da_submit_io(struct mpage_da_data *mpd) 1972 { 1973 long pages_skipped; 1974 struct pagevec pvec; 1975 unsigned long index, end; 1976 int ret = 0, err, nr_pages, i; 1977 struct inode *inode = mpd->inode; 1978 struct address_space *mapping = inode->i_mapping; 1979 1980 BUG_ON(mpd->next_page <= mpd->first_page); 1981 /* 1982 * We need to start from the first_page to the next_page - 1 1983 * to make sure we also write the mapped dirty buffer_heads. 1984 * If we look at mpd->b_blocknr we would only be looking 1985 * at the currently mapped buffer_heads. 1986 */ 1987 index = mpd->first_page; 1988 end = mpd->next_page - 1; 1989 1990 pagevec_init(&pvec, 0); 1991 while (index <= end) { 1992 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); 1993 if (nr_pages == 0) 1994 break; 1995 for (i = 0; i < nr_pages; i++) { 1996 struct page *page = pvec.pages[i]; 1997 1998 index = page->index; 1999 if (index > end) 2000 break; 2001 index++; 2002 2003 BUG_ON(!PageLocked(page)); 2004 BUG_ON(PageWriteback(page)); 2005 2006 pages_skipped = mpd->wbc->pages_skipped; 2007 err = mapping->a_ops->writepage(page, mpd->wbc); 2008 if (!err && (pages_skipped == mpd->wbc->pages_skipped)) 2009 /* 2010 * have successfully written the page 2011 * without skipping the same 2012 */ 2013 mpd->pages_written++; 2014 /* 2015 * In error case, we have to continue because 2016 * remaining pages are still locked 2017 * XXX: unlock and re-dirty them? 2018 */ 2019 if (ret == 0) 2020 ret = err; 2021 } 2022 pagevec_release(&pvec); 2023 } 2024 return ret; 2025 } 2026 2027 /* 2028 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers 2029 * 2030 * the function goes through all passed space and put actual disk 2031 * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten 2032 */ 2033 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, 2034 struct ext4_map_blocks *map) 2035 { 2036 struct inode *inode = mpd->inode; 2037 struct address_space *mapping = inode->i_mapping; 2038 int blocks = map->m_len; 2039 sector_t pblock = map->m_pblk, cur_logical; 2040 struct buffer_head *head, *bh; 2041 pgoff_t index, end; 2042 struct pagevec pvec; 2043 int nr_pages, i; 2044 2045 index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 2046 end = (map->m_lblk + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 2047 cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); 2048 2049 pagevec_init(&pvec, 0); 2050 2051 while (index <= end) { 2052 /* XXX: optimize tail */ 2053 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); 2054 if (nr_pages == 0) 2055 break; 2056 for (i = 0; i < nr_pages; i++) { 2057 struct page *page = pvec.pages[i]; 2058 2059 index = page->index; 2060 if (index > end) 2061 break; 2062 index++; 2063 2064 BUG_ON(!PageLocked(page)); 2065 BUG_ON(PageWriteback(page)); 2066 BUG_ON(!page_has_buffers(page)); 2067 2068 bh = page_buffers(page); 2069 head = bh; 2070 2071 /* skip blocks out of the range */ 2072 do { 2073 if (cur_logical >= map->m_lblk) 2074 break; 2075 cur_logical++; 2076 } while ((bh = bh->b_this_page) != head); 2077 2078 do { 2079 if (cur_logical >= map->m_lblk + blocks) 2080 break; 2081 2082 if (buffer_delay(bh) || buffer_unwritten(bh)) { 2083 2084 BUG_ON(bh->b_bdev != inode->i_sb->s_bdev); 2085 2086 if (buffer_delay(bh)) { 2087 clear_buffer_delay(bh); 2088 bh->b_blocknr = pblock; 2089 } else { 2090 /* 2091 * unwritten already should have 2092 * blocknr assigned. Verify that 2093 */ 2094 clear_buffer_unwritten(bh); 2095 BUG_ON(bh->b_blocknr != pblock); 2096 } 2097 2098 } else if (buffer_mapped(bh)) 2099 BUG_ON(bh->b_blocknr != pblock); 2100 2101 if (map->m_flags & EXT4_MAP_UNINIT) 2102 set_buffer_uninit(bh); 2103 cur_logical++; 2104 pblock++; 2105 } while ((bh = bh->b_this_page) != head); 2106 } 2107 pagevec_release(&pvec); 2108 } 2109 } 2110 2111 2112 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd, 2113 sector_t logical, long blk_cnt) 2114 { 2115 int nr_pages, i; 2116 pgoff_t index, end; 2117 struct pagevec pvec; 2118 struct inode *inode = mpd->inode; 2119 struct address_space *mapping = inode->i_mapping; 2120 2121 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits); 2122 end = (logical + blk_cnt - 1) >> 2123 (PAGE_CACHE_SHIFT - inode->i_blkbits); 2124 while (index <= end) { 2125 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); 2126 if (nr_pages == 0) 2127 break; 2128 for (i = 0; i < nr_pages; i++) { 2129 struct page *page = pvec.pages[i]; 2130 if (page->index > end) 2131 break; 2132 BUG_ON(!PageLocked(page)); 2133 BUG_ON(PageWriteback(page)); 2134 block_invalidatepage(page, 0); 2135 ClearPageUptodate(page); 2136 unlock_page(page); 2137 } 2138 index = pvec.pages[nr_pages - 1]->index + 1; 2139 pagevec_release(&pvec); 2140 } 2141 return; 2142 } 2143 2144 static void ext4_print_free_blocks(struct inode *inode) 2145 { 2146 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 2147 printk(KERN_CRIT "Total free blocks count %lld\n", 2148 ext4_count_free_blocks(inode->i_sb)); 2149 printk(KERN_CRIT "Free/Dirty block details\n"); 2150 printk(KERN_CRIT "free_blocks=%lld\n", 2151 (long long) percpu_counter_sum(&sbi->s_freeblocks_counter)); 2152 printk(KERN_CRIT "dirty_blocks=%lld\n", 2153 (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter)); 2154 printk(KERN_CRIT "Block reservation details\n"); 2155 printk(KERN_CRIT "i_reserved_data_blocks=%u\n", 2156 EXT4_I(inode)->i_reserved_data_blocks); 2157 printk(KERN_CRIT "i_reserved_meta_blocks=%u\n", 2158 EXT4_I(inode)->i_reserved_meta_blocks); 2159 return; 2160 } 2161 2162 /* 2163 * mpage_da_map_blocks - go through given space 2164 * 2165 * @mpd - bh describing space 2166 * 2167 * The function skips space we know is already mapped to disk blocks. 2168 * 2169 */ 2170 static int mpage_da_map_blocks(struct mpage_da_data *mpd) 2171 { 2172 int err, blks, get_blocks_flags; 2173 struct ext4_map_blocks map; 2174 sector_t next = mpd->b_blocknr; 2175 unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits; 2176 loff_t disksize = EXT4_I(mpd->inode)->i_disksize; 2177 handle_t *handle = NULL; 2178 2179 /* 2180 * We consider only non-mapped and non-allocated blocks 2181 */ 2182 if ((mpd->b_state & (1 << BH_Mapped)) && 2183 !(mpd->b_state & (1 << BH_Delay)) && 2184 !(mpd->b_state & (1 << BH_Unwritten))) 2185 return 0; 2186 2187 /* 2188 * If we didn't accumulate anything to write simply return 2189 */ 2190 if (!mpd->b_size) 2191 return 0; 2192 2193 handle = ext4_journal_current_handle(); 2194 BUG_ON(!handle); 2195 2196 /* 2197 * Call ext4_get_blocks() to allocate any delayed allocation 2198 * blocks, or to convert an uninitialized extent to be 2199 * initialized (in the case where we have written into 2200 * one or more preallocated blocks). 2201 * 2202 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to 2203 * indicate that we are on the delayed allocation path. This 2204 * affects functions in many different parts of the allocation 2205 * call path. This flag exists primarily because we don't 2206 * want to change *many* call functions, so ext4_get_blocks() 2207 * will set the magic i_delalloc_reserved_flag once the 2208 * inode's allocation semaphore is taken. 2209 * 2210 * If the blocks in questions were delalloc blocks, set 2211 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting 2212 * variables are updated after the blocks have been allocated. 2213 */ 2214 map.m_lblk = next; 2215 map.m_len = max_blocks; 2216 get_blocks_flags = EXT4_GET_BLOCKS_CREATE; 2217 if (ext4_should_dioread_nolock(mpd->inode)) 2218 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT; 2219 if (mpd->b_state & (1 << BH_Delay)) 2220 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE; 2221 2222 blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags); 2223 if (blks < 0) { 2224 err = blks; 2225 /* 2226 * If get block returns with error we simply 2227 * return. Later writepage will redirty the page and 2228 * writepages will find the dirty page again 2229 */ 2230 if (err == -EAGAIN) 2231 return 0; 2232 2233 if (err == -ENOSPC && 2234 ext4_count_free_blocks(mpd->inode->i_sb)) { 2235 mpd->retval = err; 2236 return 0; 2237 } 2238 2239 /* 2240 * get block failure will cause us to loop in 2241 * writepages, because a_ops->writepage won't be able 2242 * to make progress. The page will be redirtied by 2243 * writepage and writepages will again try to write 2244 * the same. 2245 */ 2246 ext4_msg(mpd->inode->i_sb, KERN_CRIT, 2247 "delayed block allocation failed for inode %lu at " 2248 "logical offset %llu with max blocks %zd with " 2249 "error %d", mpd->inode->i_ino, 2250 (unsigned long long) next, 2251 mpd->b_size >> mpd->inode->i_blkbits, err); 2252 printk(KERN_CRIT "This should not happen!! " 2253 "Data will be lost\n"); 2254 if (err == -ENOSPC) { 2255 ext4_print_free_blocks(mpd->inode); 2256 } 2257 /* invalidate all the pages */ 2258 ext4_da_block_invalidatepages(mpd, next, 2259 mpd->b_size >> mpd->inode->i_blkbits); 2260 return err; 2261 } 2262 BUG_ON(blks == 0); 2263 2264 if (map.m_flags & EXT4_MAP_NEW) { 2265 struct block_device *bdev = mpd->inode->i_sb->s_bdev; 2266 int i; 2267 2268 for (i = 0; i < map.m_len; i++) 2269 unmap_underlying_metadata(bdev, map.m_pblk + i); 2270 } 2271 2272 /* 2273 * If blocks are delayed marked, we need to 2274 * put actual blocknr and drop delayed bit 2275 */ 2276 if ((mpd->b_state & (1 << BH_Delay)) || 2277 (mpd->b_state & (1 << BH_Unwritten))) 2278 mpage_put_bnr_to_bhs(mpd, &map); 2279 2280 if (ext4_should_order_data(mpd->inode)) { 2281 err = ext4_jbd2_file_inode(handle, mpd->inode); 2282 if (err) 2283 return err; 2284 } 2285 2286 /* 2287 * Update on-disk size along with block allocation. 2288 */ 2289 disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits; 2290 if (disksize > i_size_read(mpd->inode)) 2291 disksize = i_size_read(mpd->inode); 2292 if (disksize > EXT4_I(mpd->inode)->i_disksize) { 2293 ext4_update_i_disksize(mpd->inode, disksize); 2294 return ext4_mark_inode_dirty(handle, mpd->inode); 2295 } 2296 2297 return 0; 2298 } 2299 2300 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \ 2301 (1 << BH_Delay) | (1 << BH_Unwritten)) 2302 2303 /* 2304 * mpage_add_bh_to_extent - try to add one more block to extent of blocks 2305 * 2306 * @mpd->lbh - extent of blocks 2307 * @logical - logical number of the block in the file 2308 * @bh - bh of the block (used to access block's state) 2309 * 2310 * the function is used to collect contig. blocks in same state 2311 */ 2312 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, 2313 sector_t logical, size_t b_size, 2314 unsigned long b_state) 2315 { 2316 sector_t next; 2317 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits; 2318 2319 /* 2320 * XXX Don't go larger than mballoc is willing to allocate 2321 * This is a stopgap solution. We eventually need to fold 2322 * mpage_da_submit_io() into this function and then call 2323 * ext4_get_blocks() multiple times in a loop 2324 */ 2325 if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize) 2326 goto flush_it; 2327 2328 /* check if thereserved journal credits might overflow */ 2329 if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) { 2330 if (nrblocks >= EXT4_MAX_TRANS_DATA) { 2331 /* 2332 * With non-extent format we are limited by the journal 2333 * credit available. Total credit needed to insert 2334 * nrblocks contiguous blocks is dependent on the 2335 * nrblocks. So limit nrblocks. 2336 */ 2337 goto flush_it; 2338 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) > 2339 EXT4_MAX_TRANS_DATA) { 2340 /* 2341 * Adding the new buffer_head would make it cross the 2342 * allowed limit for which we have journal credit 2343 * reserved. So limit the new bh->b_size 2344 */ 2345 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) << 2346 mpd->inode->i_blkbits; 2347 /* we will do mpage_da_submit_io in the next loop */ 2348 } 2349 } 2350 /* 2351 * First block in the extent 2352 */ 2353 if (mpd->b_size == 0) { 2354 mpd->b_blocknr = logical; 2355 mpd->b_size = b_size; 2356 mpd->b_state = b_state & BH_FLAGS; 2357 return; 2358 } 2359 2360 next = mpd->b_blocknr + nrblocks; 2361 /* 2362 * Can we merge the block to our big extent? 2363 */ 2364 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) { 2365 mpd->b_size += b_size; 2366 return; 2367 } 2368 2369 flush_it: 2370 /* 2371 * We couldn't merge the block to our extent, so we 2372 * need to flush current extent and start new one 2373 */ 2374 if (mpage_da_map_blocks(mpd) == 0) 2375 mpage_da_submit_io(mpd); 2376 mpd->io_done = 1; 2377 return; 2378 } 2379 2380 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh) 2381 { 2382 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh); 2383 } 2384 2385 /* 2386 * __mpage_da_writepage - finds extent of pages and blocks 2387 * 2388 * @page: page to consider 2389 * @wbc: not used, we just follow rules 2390 * @data: context 2391 * 2392 * The function finds extents of pages and scan them for all blocks. 2393 */ 2394 static int __mpage_da_writepage(struct page *page, 2395 struct writeback_control *wbc, void *data) 2396 { 2397 struct mpage_da_data *mpd = data; 2398 struct inode *inode = mpd->inode; 2399 struct buffer_head *bh, *head; 2400 sector_t logical; 2401 2402 /* 2403 * Can we merge this page to current extent? 2404 */ 2405 if (mpd->next_page != page->index) { 2406 /* 2407 * Nope, we can't. So, we map non-allocated blocks 2408 * and start IO on them using writepage() 2409 */ 2410 if (mpd->next_page != mpd->first_page) { 2411 if (mpage_da_map_blocks(mpd) == 0) 2412 mpage_da_submit_io(mpd); 2413 /* 2414 * skip rest of the page in the page_vec 2415 */ 2416 mpd->io_done = 1; 2417 redirty_page_for_writepage(wbc, page); 2418 unlock_page(page); 2419 return MPAGE_DA_EXTENT_TAIL; 2420 } 2421 2422 /* 2423 * Start next extent of pages ... 2424 */ 2425 mpd->first_page = page->index; 2426 2427 /* 2428 * ... and blocks 2429 */ 2430 mpd->b_size = 0; 2431 mpd->b_state = 0; 2432 mpd->b_blocknr = 0; 2433 } 2434 2435 mpd->next_page = page->index + 1; 2436 logical = (sector_t) page->index << 2437 (PAGE_CACHE_SHIFT - inode->i_blkbits); 2438 2439 if (!page_has_buffers(page)) { 2440 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE, 2441 (1 << BH_Dirty) | (1 << BH_Uptodate)); 2442 if (mpd->io_done) 2443 return MPAGE_DA_EXTENT_TAIL; 2444 } else { 2445 /* 2446 * Page with regular buffer heads, just add all dirty ones 2447 */ 2448 head = page_buffers(page); 2449 bh = head; 2450 do { 2451 BUG_ON(buffer_locked(bh)); 2452 /* 2453 * We need to try to allocate 2454 * unmapped blocks in the same page. 2455 * Otherwise we won't make progress 2456 * with the page in ext4_writepage 2457 */ 2458 if (ext4_bh_delay_or_unwritten(NULL, bh)) { 2459 mpage_add_bh_to_extent(mpd, logical, 2460 bh->b_size, 2461 bh->b_state); 2462 if (mpd->io_done) 2463 return MPAGE_DA_EXTENT_TAIL; 2464 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) { 2465 /* 2466 * mapped dirty buffer. We need to update 2467 * the b_state because we look at 2468 * b_state in mpage_da_map_blocks. We don't 2469 * update b_size because if we find an 2470 * unmapped buffer_head later we need to 2471 * use the b_state flag of that buffer_head. 2472 */ 2473 if (mpd->b_size == 0) 2474 mpd->b_state = bh->b_state & BH_FLAGS; 2475 } 2476 logical++; 2477 } while ((bh = bh->b_this_page) != head); 2478 } 2479 2480 return 0; 2481 } 2482 2483 /* 2484 * This is a special get_blocks_t callback which is used by 2485 * ext4_da_write_begin(). It will either return mapped block or 2486 * reserve space for a single block. 2487 * 2488 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set. 2489 * We also have b_blocknr = -1 and b_bdev initialized properly 2490 * 2491 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set. 2492 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev 2493 * initialized properly. 2494 */ 2495 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, 2496 struct buffer_head *bh, int create) 2497 { 2498 struct ext4_map_blocks map; 2499 int ret = 0; 2500 sector_t invalid_block = ~((sector_t) 0xffff); 2501 2502 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es)) 2503 invalid_block = ~0; 2504 2505 BUG_ON(create == 0); 2506 BUG_ON(bh->b_size != inode->i_sb->s_blocksize); 2507 2508 map.m_lblk = iblock; 2509 map.m_len = 1; 2510 2511 /* 2512 * first, we need to know whether the block is allocated already 2513 * preallocated blocks are unmapped but should treated 2514 * the same as allocated blocks. 2515 */ 2516 ret = ext4_map_blocks(NULL, inode, &map, 0); 2517 if (ret < 0) 2518 return ret; 2519 if (ret == 0) { 2520 if (buffer_delay(bh)) 2521 return 0; /* Not sure this could or should happen */ 2522 /* 2523 * XXX: __block_prepare_write() unmaps passed block, 2524 * is it OK? 2525 */ 2526 ret = ext4_da_reserve_space(inode, iblock); 2527 if (ret) 2528 /* not enough space to reserve */ 2529 return ret; 2530 2531 map_bh(bh, inode->i_sb, invalid_block); 2532 set_buffer_new(bh); 2533 set_buffer_delay(bh); 2534 return 0; 2535 } 2536 2537 map_bh(bh, inode->i_sb, map.m_pblk); 2538 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; 2539 2540 if (buffer_unwritten(bh)) { 2541 /* A delayed write to unwritten bh should be marked 2542 * new and mapped. Mapped ensures that we don't do 2543 * get_block multiple times when we write to the same 2544 * offset and new ensures that we do proper zero out 2545 * for partial write. 2546 */ 2547 set_buffer_new(bh); 2548 set_buffer_mapped(bh); 2549 } 2550 return 0; 2551 } 2552 2553 /* 2554 * This function is used as a standard get_block_t calback function 2555 * when there is no desire to allocate any blocks. It is used as a 2556 * callback function for block_prepare_write(), nobh_writepage(), and 2557 * block_write_full_page(). These functions should only try to map a 2558 * single block at a time. 2559 * 2560 * Since this function doesn't do block allocations even if the caller 2561 * requests it by passing in create=1, it is critically important that 2562 * any caller checks to make sure that any buffer heads are returned 2563 * by this function are either all already mapped or marked for 2564 * delayed allocation before calling nobh_writepage() or 2565 * block_write_full_page(). Otherwise, b_blocknr could be left 2566 * unitialized, and the page write functions will be taken by 2567 * surprise. 2568 */ 2569 static int noalloc_get_block_write(struct inode *inode, sector_t iblock, 2570 struct buffer_head *bh_result, int create) 2571 { 2572 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize); 2573 return _ext4_get_block(inode, iblock, bh_result, 0); 2574 } 2575 2576 static int bget_one(handle_t *handle, struct buffer_head *bh) 2577 { 2578 get_bh(bh); 2579 return 0; 2580 } 2581 2582 static int bput_one(handle_t *handle, struct buffer_head *bh) 2583 { 2584 put_bh(bh); 2585 return 0; 2586 } 2587 2588 static int __ext4_journalled_writepage(struct page *page, 2589 unsigned int len) 2590 { 2591 struct address_space *mapping = page->mapping; 2592 struct inode *inode = mapping->host; 2593 struct buffer_head *page_bufs; 2594 handle_t *handle = NULL; 2595 int ret = 0; 2596 int err; 2597 2598 page_bufs = page_buffers(page); 2599 BUG_ON(!page_bufs); 2600 walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one); 2601 /* As soon as we unlock the page, it can go away, but we have 2602 * references to buffers so we are safe */ 2603 unlock_page(page); 2604 2605 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); 2606 if (IS_ERR(handle)) { 2607 ret = PTR_ERR(handle); 2608 goto out; 2609 } 2610 2611 ret = walk_page_buffers(handle, page_bufs, 0, len, NULL, 2612 do_journal_get_write_access); 2613 2614 err = walk_page_buffers(handle, page_bufs, 0, len, NULL, 2615 write_end_fn); 2616 if (ret == 0) 2617 ret = err; 2618 err = ext4_journal_stop(handle); 2619 if (!ret) 2620 ret = err; 2621 2622 walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one); 2623 ext4_set_inode_state(inode, EXT4_STATE_JDATA); 2624 out: 2625 return ret; 2626 } 2627 2628 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode); 2629 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate); 2630 2631 /* 2632 * Note that we don't need to start a transaction unless we're journaling data 2633 * because we should have holes filled from ext4_page_mkwrite(). We even don't 2634 * need to file the inode to the transaction's list in ordered mode because if 2635 * we are writing back data added by write(), the inode is already there and if 2636 * we are writing back data modified via mmap(), noone guarantees in which 2637 * transaction the data will hit the disk. In case we are journaling data, we 2638 * cannot start transaction directly because transaction start ranks above page 2639 * lock so we have to do some magic. 2640 * 2641 * This function can get called via... 2642 * - ext4_da_writepages after taking page lock (have journal handle) 2643 * - journal_submit_inode_data_buffers (no journal handle) 2644 * - shrink_page_list via pdflush (no journal handle) 2645 * - grab_page_cache when doing write_begin (have journal handle) 2646 * 2647 * We don't do any block allocation in this function. If we have page with 2648 * multiple blocks we need to write those buffer_heads that are mapped. This 2649 * is important for mmaped based write. So if we do with blocksize 1K 2650 * truncate(f, 1024); 2651 * a = mmap(f, 0, 4096); 2652 * a[0] = 'a'; 2653 * truncate(f, 4096); 2654 * we have in the page first buffer_head mapped via page_mkwrite call back 2655 * but other bufer_heads would be unmapped but dirty(dirty done via the 2656 * do_wp_page). So writepage should write the first block. If we modify 2657 * the mmap area beyond 1024 we will again get a page_fault and the 2658 * page_mkwrite callback will do the block allocation and mark the 2659 * buffer_heads mapped. 2660 * 2661 * We redirty the page if we have any buffer_heads that is either delay or 2662 * unwritten in the page. 2663 * 2664 * We can get recursively called as show below. 2665 * 2666 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> 2667 * ext4_writepage() 2668 * 2669 * But since we don't do any block allocation we should not deadlock. 2670 * Page also have the dirty flag cleared so we don't get recurive page_lock. 2671 */ 2672 static int ext4_writepage(struct page *page, 2673 struct writeback_control *wbc) 2674 { 2675 int ret = 0; 2676 loff_t size; 2677 unsigned int len; 2678 struct buffer_head *page_bufs = NULL; 2679 struct inode *inode = page->mapping->host; 2680 2681 trace_ext4_writepage(inode, page); 2682 size = i_size_read(inode); 2683 if (page->index == size >> PAGE_CACHE_SHIFT) 2684 len = size & ~PAGE_CACHE_MASK; 2685 else 2686 len = PAGE_CACHE_SIZE; 2687 2688 if (page_has_buffers(page)) { 2689 page_bufs = page_buffers(page); 2690 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, 2691 ext4_bh_delay_or_unwritten)) { 2692 /* 2693 * We don't want to do block allocation 2694 * So redirty the page and return 2695 * We may reach here when we do a journal commit 2696 * via journal_submit_inode_data_buffers. 2697 * If we don't have mapping block we just ignore 2698 * them. We can also reach here via shrink_page_list 2699 */ 2700 redirty_page_for_writepage(wbc, page); 2701 unlock_page(page); 2702 return 0; 2703 } 2704 } else { 2705 /* 2706 * The test for page_has_buffers() is subtle: 2707 * We know the page is dirty but it lost buffers. That means 2708 * that at some moment in time after write_begin()/write_end() 2709 * has been called all buffers have been clean and thus they 2710 * must have been written at least once. So they are all 2711 * mapped and we can happily proceed with mapping them 2712 * and writing the page. 2713 * 2714 * Try to initialize the buffer_heads and check whether 2715 * all are mapped and non delay. We don't want to 2716 * do block allocation here. 2717 */ 2718 ret = block_prepare_write(page, 0, len, 2719 noalloc_get_block_write); 2720 if (!ret) { 2721 page_bufs = page_buffers(page); 2722 /* check whether all are mapped and non delay */ 2723 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, 2724 ext4_bh_delay_or_unwritten)) { 2725 redirty_page_for_writepage(wbc, page); 2726 unlock_page(page); 2727 return 0; 2728 } 2729 } else { 2730 /* 2731 * We can't do block allocation here 2732 * so just redity the page and unlock 2733 * and return 2734 */ 2735 redirty_page_for_writepage(wbc, page); 2736 unlock_page(page); 2737 return 0; 2738 } 2739 /* now mark the buffer_heads as dirty and uptodate */ 2740 block_commit_write(page, 0, len); 2741 } 2742 2743 if (PageChecked(page) && ext4_should_journal_data(inode)) { 2744 /* 2745 * It's mmapped pagecache. Add buffers and journal it. There 2746 * doesn't seem much point in redirtying the page here. 2747 */ 2748 ClearPageChecked(page); 2749 return __ext4_journalled_writepage(page, len); 2750 } 2751 2752 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode)) 2753 ret = nobh_writepage(page, noalloc_get_block_write, wbc); 2754 else if (page_bufs && buffer_uninit(page_bufs)) { 2755 ext4_set_bh_endio(page_bufs, inode); 2756 ret = block_write_full_page_endio(page, noalloc_get_block_write, 2757 wbc, ext4_end_io_buffer_write); 2758 } else 2759 ret = block_write_full_page(page, noalloc_get_block_write, 2760 wbc); 2761 2762 return ret; 2763 } 2764 2765 /* 2766 * This is called via ext4_da_writepages() to 2767 * calulate the total number of credits to reserve to fit 2768 * a single extent allocation into a single transaction, 2769 * ext4_da_writpeages() will loop calling this before 2770 * the block allocation. 2771 */ 2772 2773 static int ext4_da_writepages_trans_blocks(struct inode *inode) 2774 { 2775 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks; 2776 2777 /* 2778 * With non-extent format the journal credit needed to 2779 * insert nrblocks contiguous block is dependent on 2780 * number of contiguous block. So we will limit 2781 * number of contiguous block to a sane value 2782 */ 2783 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) && 2784 (max_blocks > EXT4_MAX_TRANS_DATA)) 2785 max_blocks = EXT4_MAX_TRANS_DATA; 2786 2787 return ext4_chunk_trans_blocks(inode, max_blocks); 2788 } 2789 2790 /* 2791 * write_cache_pages_da - walk the list of dirty pages of the given 2792 * address space and call the callback function (which usually writes 2793 * the pages). 2794 * 2795 * This is a forked version of write_cache_pages(). Differences: 2796 * Range cyclic is ignored. 2797 * no_nrwrite_index_update is always presumed true 2798 */ 2799 static int write_cache_pages_da(struct address_space *mapping, 2800 struct writeback_control *wbc, 2801 struct mpage_da_data *mpd) 2802 { 2803 int ret = 0; 2804 int done = 0; 2805 struct pagevec pvec; 2806 int nr_pages; 2807 pgoff_t index; 2808 pgoff_t end; /* Inclusive */ 2809 long nr_to_write = wbc->nr_to_write; 2810 2811 pagevec_init(&pvec, 0); 2812 index = wbc->range_start >> PAGE_CACHE_SHIFT; 2813 end = wbc->range_end >> PAGE_CACHE_SHIFT; 2814 2815 while (!done && (index <= end)) { 2816 int i; 2817 2818 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, 2819 PAGECACHE_TAG_DIRTY, 2820 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); 2821 if (nr_pages == 0) 2822 break; 2823 2824 for (i = 0; i < nr_pages; i++) { 2825 struct page *page = pvec.pages[i]; 2826 2827 /* 2828 * At this point, the page may be truncated or 2829 * invalidated (changing page->mapping to NULL), or 2830 * even swizzled back from swapper_space to tmpfs file 2831 * mapping. However, page->index will not change 2832 * because we have a reference on the page. 2833 */ 2834 if (page->index > end) { 2835 done = 1; 2836 break; 2837 } 2838 2839 lock_page(page); 2840 2841 /* 2842 * Page truncated or invalidated. We can freely skip it 2843 * then, even for data integrity operations: the page 2844 * has disappeared concurrently, so there could be no 2845 * real expectation of this data interity operation 2846 * even if there is now a new, dirty page at the same 2847 * pagecache address. 2848 */ 2849 if (unlikely(page->mapping != mapping)) { 2850 continue_unlock: 2851 unlock_page(page); 2852 continue; 2853 } 2854 2855 if (!PageDirty(page)) { 2856 /* someone wrote it for us */ 2857 goto continue_unlock; 2858 } 2859 2860 if (PageWriteback(page)) { 2861 if (wbc->sync_mode != WB_SYNC_NONE) 2862 wait_on_page_writeback(page); 2863 else 2864 goto continue_unlock; 2865 } 2866 2867 BUG_ON(PageWriteback(page)); 2868 if (!clear_page_dirty_for_io(page)) 2869 goto continue_unlock; 2870 2871 ret = __mpage_da_writepage(page, wbc, mpd); 2872 if (unlikely(ret)) { 2873 if (ret == AOP_WRITEPAGE_ACTIVATE) { 2874 unlock_page(page); 2875 ret = 0; 2876 } else { 2877 done = 1; 2878 break; 2879 } 2880 } 2881 2882 if (nr_to_write > 0) { 2883 nr_to_write--; 2884 if (nr_to_write == 0 && 2885 wbc->sync_mode == WB_SYNC_NONE) { 2886 /* 2887 * We stop writing back only if we are 2888 * not doing integrity sync. In case of 2889 * integrity sync we have to keep going 2890 * because someone may be concurrently 2891 * dirtying pages, and we might have 2892 * synced a lot of newly appeared dirty 2893 * pages, but have not synced all of the 2894 * old dirty pages. 2895 */ 2896 done = 1; 2897 break; 2898 } 2899 } 2900 } 2901 pagevec_release(&pvec); 2902 cond_resched(); 2903 } 2904 return ret; 2905 } 2906 2907 2908 static int ext4_da_writepages(struct address_space *mapping, 2909 struct writeback_control *wbc) 2910 { 2911 pgoff_t index; 2912 int range_whole = 0; 2913 handle_t *handle = NULL; 2914 struct mpage_da_data mpd; 2915 struct inode *inode = mapping->host; 2916 int pages_written = 0; 2917 long pages_skipped; 2918 unsigned int max_pages; 2919 int range_cyclic, cycled = 1, io_done = 0; 2920 int needed_blocks, ret = 0; 2921 long desired_nr_to_write, nr_to_writebump = 0; 2922 loff_t range_start = wbc->range_start; 2923 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); 2924 2925 trace_ext4_da_writepages(inode, wbc); 2926 2927 /* 2928 * No pages to write? This is mainly a kludge to avoid starting 2929 * a transaction for special inodes like journal inode on last iput() 2930 * because that could violate lock ordering on umount 2931 */ 2932 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) 2933 return 0; 2934 2935 /* 2936 * If the filesystem has aborted, it is read-only, so return 2937 * right away instead of dumping stack traces later on that 2938 * will obscure the real source of the problem. We test 2939 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because 2940 * the latter could be true if the filesystem is mounted 2941 * read-only, and in that case, ext4_da_writepages should 2942 * *never* be called, so if that ever happens, we would want 2943 * the stack trace. 2944 */ 2945 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) 2946 return -EROFS; 2947 2948 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 2949 range_whole = 1; 2950 2951 range_cyclic = wbc->range_cyclic; 2952 if (wbc->range_cyclic) { 2953 index = mapping->writeback_index; 2954 if (index) 2955 cycled = 0; 2956 wbc->range_start = index << PAGE_CACHE_SHIFT; 2957 wbc->range_end = LLONG_MAX; 2958 wbc->range_cyclic = 0; 2959 } else 2960 index = wbc->range_start >> PAGE_CACHE_SHIFT; 2961 2962 /* 2963 * This works around two forms of stupidity. The first is in 2964 * the writeback code, which caps the maximum number of pages 2965 * written to be 1024 pages. This is wrong on multiple 2966 * levels; different architectues have a different page size, 2967 * which changes the maximum amount of data which gets 2968 * written. Secondly, 4 megabytes is way too small. XFS 2969 * forces this value to be 16 megabytes by multiplying 2970 * nr_to_write parameter by four, and then relies on its 2971 * allocator to allocate larger extents to make them 2972 * contiguous. Unfortunately this brings us to the second 2973 * stupidity, which is that ext4's mballoc code only allocates 2974 * at most 2048 blocks. So we force contiguous writes up to 2975 * the number of dirty blocks in the inode, or 2976 * sbi->max_writeback_mb_bump whichever is smaller. 2977 */ 2978 max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT); 2979 if (!range_cyclic && range_whole) 2980 desired_nr_to_write = wbc->nr_to_write * 8; 2981 else 2982 desired_nr_to_write = ext4_num_dirty_pages(inode, index, 2983 max_pages); 2984 if (desired_nr_to_write > max_pages) 2985 desired_nr_to_write = max_pages; 2986 2987 if (wbc->nr_to_write < desired_nr_to_write) { 2988 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write; 2989 wbc->nr_to_write = desired_nr_to_write; 2990 } 2991 2992 mpd.wbc = wbc; 2993 mpd.inode = mapping->host; 2994 2995 pages_skipped = wbc->pages_skipped; 2996 2997 retry: 2998 while (!ret && wbc->nr_to_write > 0) { 2999 3000 /* 3001 * we insert one extent at a time. So we need 3002 * credit needed for single extent allocation. 3003 * journalled mode is currently not supported 3004 * by delalloc 3005 */ 3006 BUG_ON(ext4_should_journal_data(inode)); 3007 needed_blocks = ext4_da_writepages_trans_blocks(inode); 3008 3009 /* start a new transaction*/ 3010 handle = ext4_journal_start(inode, needed_blocks); 3011 if (IS_ERR(handle)) { 3012 ret = PTR_ERR(handle); 3013 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: " 3014 "%ld pages, ino %lu; err %d", __func__, 3015 wbc->nr_to_write, inode->i_ino, ret); 3016 goto out_writepages; 3017 } 3018 3019 /* 3020 * Now call __mpage_da_writepage to find the next 3021 * contiguous region of logical blocks that need 3022 * blocks to be allocated by ext4. We don't actually 3023 * submit the blocks for I/O here, even though 3024 * write_cache_pages thinks it will, and will set the 3025 * pages as clean for write before calling 3026 * __mpage_da_writepage(). 3027 */ 3028 mpd.b_size = 0; 3029 mpd.b_state = 0; 3030 mpd.b_blocknr = 0; 3031 mpd.first_page = 0; 3032 mpd.next_page = 0; 3033 mpd.io_done = 0; 3034 mpd.pages_written = 0; 3035 mpd.retval = 0; 3036 ret = write_cache_pages_da(mapping, wbc, &mpd); 3037 /* 3038 * If we have a contiguous extent of pages and we 3039 * haven't done the I/O yet, map the blocks and submit 3040 * them for I/O. 3041 */ 3042 if (!mpd.io_done && mpd.next_page != mpd.first_page) { 3043 if (mpage_da_map_blocks(&mpd) == 0) 3044 mpage_da_submit_io(&mpd); 3045 mpd.io_done = 1; 3046 ret = MPAGE_DA_EXTENT_TAIL; 3047 } 3048 trace_ext4_da_write_pages(inode, &mpd); 3049 wbc->nr_to_write -= mpd.pages_written; 3050 3051 ext4_journal_stop(handle); 3052 3053 if ((mpd.retval == -ENOSPC) && sbi->s_journal) { 3054 /* commit the transaction which would 3055 * free blocks released in the transaction 3056 * and try again 3057 */ 3058 jbd2_journal_force_commit_nested(sbi->s_journal); 3059 wbc->pages_skipped = pages_skipped; 3060 ret = 0; 3061 } else if (ret == MPAGE_DA_EXTENT_TAIL) { 3062 /* 3063 * got one extent now try with 3064 * rest of the pages 3065 */ 3066 pages_written += mpd.pages_written; 3067 wbc->pages_skipped = pages_skipped; 3068 ret = 0; 3069 io_done = 1; 3070 } else if (wbc->nr_to_write) 3071 /* 3072 * There is no more writeout needed 3073 * or we requested for a noblocking writeout 3074 * and we found the device congested 3075 */ 3076 break; 3077 } 3078 if (!io_done && !cycled) { 3079 cycled = 1; 3080 index = 0; 3081 wbc->range_start = index << PAGE_CACHE_SHIFT; 3082 wbc->range_end = mapping->writeback_index - 1; 3083 goto retry; 3084 } 3085 if (pages_skipped != wbc->pages_skipped) 3086 ext4_msg(inode->i_sb, KERN_CRIT, 3087 "This should not happen leaving %s " 3088 "with nr_to_write = %ld ret = %d", 3089 __func__, wbc->nr_to_write, ret); 3090 3091 /* Update index */ 3092 index += pages_written; 3093 wbc->range_cyclic = range_cyclic; 3094 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 3095 /* 3096 * set the writeback_index so that range_cyclic 3097 * mode will write it back later 3098 */ 3099 mapping->writeback_index = index; 3100 3101 out_writepages: 3102 wbc->nr_to_write -= nr_to_writebump; 3103 wbc->range_start = range_start; 3104 trace_ext4_da_writepages_result(inode, wbc, ret, pages_written); 3105 return ret; 3106 } 3107 3108 #define FALL_BACK_TO_NONDELALLOC 1 3109 static int ext4_nonda_switch(struct super_block *sb) 3110 { 3111 s64 free_blocks, dirty_blocks; 3112 struct ext4_sb_info *sbi = EXT4_SB(sb); 3113 3114 /* 3115 * switch to non delalloc mode if we are running low 3116 * on free block. The free block accounting via percpu 3117 * counters can get slightly wrong with percpu_counter_batch getting 3118 * accumulated on each CPU without updating global counters 3119 * Delalloc need an accurate free block accounting. So switch 3120 * to non delalloc when we are near to error range. 3121 */ 3122 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); 3123 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter); 3124 if (2 * free_blocks < 3 * dirty_blocks || 3125 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) { 3126 /* 3127 * free block count is less than 150% of dirty blocks 3128 * or free blocks is less than watermark 3129 */ 3130 return 1; 3131 } 3132 /* 3133 * Even if we don't switch but are nearing capacity, 3134 * start pushing delalloc when 1/2 of free blocks are dirty. 3135 */ 3136 if (free_blocks < 2 * dirty_blocks) 3137 writeback_inodes_sb_if_idle(sb); 3138 3139 return 0; 3140 } 3141 3142 static int ext4_da_write_begin(struct file *file, struct address_space *mapping, 3143 loff_t pos, unsigned len, unsigned flags, 3144 struct page **pagep, void **fsdata) 3145 { 3146 int ret, retries = 0; 3147 struct page *page; 3148 pgoff_t index; 3149 unsigned from, to; 3150 struct inode *inode = mapping->host; 3151 handle_t *handle; 3152 3153 index = pos >> PAGE_CACHE_SHIFT; 3154 from = pos & (PAGE_CACHE_SIZE - 1); 3155 to = from + len; 3156 3157 if (ext4_nonda_switch(inode->i_sb)) { 3158 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC; 3159 return ext4_write_begin(file, mapping, pos, 3160 len, flags, pagep, fsdata); 3161 } 3162 *fsdata = (void *)0; 3163 trace_ext4_da_write_begin(inode, pos, len, flags); 3164 retry: 3165 /* 3166 * With delayed allocation, we don't log the i_disksize update 3167 * if there is delayed block allocation. But we still need 3168 * to journalling the i_disksize update if writes to the end 3169 * of file which has an already mapped buffer. 3170 */ 3171 handle = ext4_journal_start(inode, 1); 3172 if (IS_ERR(handle)) { 3173 ret = PTR_ERR(handle); 3174 goto out; 3175 } 3176 /* We cannot recurse into the filesystem as the transaction is already 3177 * started */ 3178 flags |= AOP_FLAG_NOFS; 3179 3180 page = grab_cache_page_write_begin(mapping, index, flags); 3181 if (!page) { 3182 ext4_journal_stop(handle); 3183 ret = -ENOMEM; 3184 goto out; 3185 } 3186 *pagep = page; 3187 3188 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 3189 ext4_da_get_block_prep); 3190 if (ret < 0) { 3191 unlock_page(page); 3192 ext4_journal_stop(handle); 3193 page_cache_release(page); 3194 /* 3195 * block_write_begin may have instantiated a few blocks 3196 * outside i_size. Trim these off again. Don't need 3197 * i_size_read because we hold i_mutex. 3198 */ 3199 if (pos + len > inode->i_size) 3200 ext4_truncate_failed_write(inode); 3201 } 3202 3203 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) 3204 goto retry; 3205 out: 3206 return ret; 3207 } 3208 3209 /* 3210 * Check if we should update i_disksize 3211 * when write to the end of file but not require block allocation 3212 */ 3213 static int ext4_da_should_update_i_disksize(struct page *page, 3214 unsigned long offset) 3215 { 3216 struct buffer_head *bh; 3217 struct inode *inode = page->mapping->host; 3218 unsigned int idx; 3219 int i; 3220 3221 bh = page_buffers(page); 3222 idx = offset >> inode->i_blkbits; 3223 3224 for (i = 0; i < idx; i++) 3225 bh = bh->b_this_page; 3226 3227 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh)) 3228 return 0; 3229 return 1; 3230 } 3231 3232 static int ext4_da_write_end(struct file *file, 3233 struct address_space *mapping, 3234 loff_t pos, unsigned len, unsigned copied, 3235 struct page *page, void *fsdata) 3236 { 3237 struct inode *inode = mapping->host; 3238 int ret = 0, ret2; 3239 handle_t *handle = ext4_journal_current_handle(); 3240 loff_t new_i_size; 3241 unsigned long start, end; 3242 int write_mode = (int)(unsigned long)fsdata; 3243 3244 if (write_mode == FALL_BACK_TO_NONDELALLOC) { 3245 if (ext4_should_order_data(inode)) { 3246 return ext4_ordered_write_end(file, mapping, pos, 3247 len, copied, page, fsdata); 3248 } else if (ext4_should_writeback_data(inode)) { 3249 return ext4_writeback_write_end(file, mapping, pos, 3250 len, copied, page, fsdata); 3251 } else { 3252 BUG(); 3253 } 3254 } 3255 3256 trace_ext4_da_write_end(inode, pos, len, copied); 3257 start = pos & (PAGE_CACHE_SIZE - 1); 3258 end = start + copied - 1; 3259 3260 /* 3261 * generic_write_end() will run mark_inode_dirty() if i_size 3262 * changes. So let's piggyback the i_disksize mark_inode_dirty 3263 * into that. 3264 */ 3265 3266 new_i_size = pos + copied; 3267 if (new_i_size > EXT4_I(inode)->i_disksize) { 3268 if (ext4_da_should_update_i_disksize(page, end)) { 3269 down_write(&EXT4_I(inode)->i_data_sem); 3270 if (new_i_size > EXT4_I(inode)->i_disksize) { 3271 /* 3272 * Updating i_disksize when extending file 3273 * without needing block allocation 3274 */ 3275 if (ext4_should_order_data(inode)) 3276 ret = ext4_jbd2_file_inode(handle, 3277 inode); 3278 3279 EXT4_I(inode)->i_disksize = new_i_size; 3280 } 3281 up_write(&EXT4_I(inode)->i_data_sem); 3282 /* We need to mark inode dirty even if 3283 * new_i_size is less that inode->i_size 3284 * bu greater than i_disksize.(hint delalloc) 3285 */ 3286 ext4_mark_inode_dirty(handle, inode); 3287 } 3288 } 3289 ret2 = generic_write_end(file, mapping, pos, len, copied, 3290 page, fsdata); 3291 copied = ret2; 3292 if (ret2 < 0) 3293 ret = ret2; 3294 ret2 = ext4_journal_stop(handle); 3295 if (!ret) 3296 ret = ret2; 3297 3298 return ret ? ret : copied; 3299 } 3300 3301 static void ext4_da_invalidatepage(struct page *page, unsigned long offset) 3302 { 3303 /* 3304 * Drop reserved blocks 3305 */ 3306 BUG_ON(!PageLocked(page)); 3307 if (!page_has_buffers(page)) 3308 goto out; 3309 3310 ext4_da_page_release_reservation(page, offset); 3311 3312 out: 3313 ext4_invalidatepage(page, offset); 3314 3315 return; 3316 } 3317 3318 /* 3319 * Force all delayed allocation blocks to be allocated for a given inode. 3320 */ 3321 int ext4_alloc_da_blocks(struct inode *inode) 3322 { 3323 trace_ext4_alloc_da_blocks(inode); 3324 3325 if (!EXT4_I(inode)->i_reserved_data_blocks && 3326 !EXT4_I(inode)->i_reserved_meta_blocks) 3327 return 0; 3328 3329 /* 3330 * We do something simple for now. The filemap_flush() will 3331 * also start triggering a write of the data blocks, which is 3332 * not strictly speaking necessary (and for users of 3333 * laptop_mode, not even desirable). However, to do otherwise 3334 * would require replicating code paths in: 3335 * 3336 * ext4_da_writepages() -> 3337 * write_cache_pages() ---> (via passed in callback function) 3338 * __mpage_da_writepage() --> 3339 * mpage_add_bh_to_extent() 3340 * mpage_da_map_blocks() 3341 * 3342 * The problem is that write_cache_pages(), located in 3343 * mm/page-writeback.c, marks pages clean in preparation for 3344 * doing I/O, which is not desirable if we're not planning on 3345 * doing I/O at all. 3346 * 3347 * We could call write_cache_pages(), and then redirty all of 3348 * the pages by calling redirty_page_for_writeback() but that 3349 * would be ugly in the extreme. So instead we would need to 3350 * replicate parts of the code in the above functions, 3351 * simplifying them becuase we wouldn't actually intend to 3352 * write out the pages, but rather only collect contiguous 3353 * logical block extents, call the multi-block allocator, and 3354 * then update the buffer heads with the block allocations. 3355 * 3356 * For now, though, we'll cheat by calling filemap_flush(), 3357 * which will map the blocks, and start the I/O, but not 3358 * actually wait for the I/O to complete. 3359 */ 3360 return filemap_flush(inode->i_mapping); 3361 } 3362 3363 /* 3364 * bmap() is special. It gets used by applications such as lilo and by 3365 * the swapper to find the on-disk block of a specific piece of data. 3366 * 3367 * Naturally, this is dangerous if the block concerned is still in the 3368 * journal. If somebody makes a swapfile on an ext4 data-journaling 3369 * filesystem and enables swap, then they may get a nasty shock when the 3370 * data getting swapped to that swapfile suddenly gets overwritten by 3371 * the original zero's written out previously to the journal and 3372 * awaiting writeback in the kernel's buffer cache. 3373 * 3374 * So, if we see any bmap calls here on a modified, data-journaled file, 3375 * take extra steps to flush any blocks which might be in the cache. 3376 */ 3377 static sector_t ext4_bmap(struct address_space *mapping, sector_t block) 3378 { 3379 struct inode *inode = mapping->host; 3380 journal_t *journal; 3381 int err; 3382 3383 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && 3384 test_opt(inode->i_sb, DELALLOC)) { 3385 /* 3386 * With delalloc we want to sync the file 3387 * so that we can make sure we allocate 3388 * blocks for file 3389 */ 3390 filemap_write_and_wait(mapping); 3391 } 3392 3393 if (EXT4_JOURNAL(inode) && 3394 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) { 3395 /* 3396 * This is a REALLY heavyweight approach, but the use of 3397 * bmap on dirty files is expected to be extremely rare: 3398 * only if we run lilo or swapon on a freshly made file 3399 * do we expect this to happen. 3400 * 3401 * (bmap requires CAP_SYS_RAWIO so this does not 3402 * represent an unprivileged user DOS attack --- we'd be 3403 * in trouble if mortal users could trigger this path at 3404 * will.) 3405 * 3406 * NB. EXT4_STATE_JDATA is not set on files other than 3407 * regular files. If somebody wants to bmap a directory 3408 * or symlink and gets confused because the buffer 3409 * hasn't yet been flushed to disk, they deserve 3410 * everything they get. 3411 */ 3412 3413 ext4_clear_inode_state(inode, EXT4_STATE_JDATA); 3414 journal = EXT4_JOURNAL(inode); 3415 jbd2_journal_lock_updates(journal); 3416 err = jbd2_journal_flush(journal); 3417 jbd2_journal_unlock_updates(journal); 3418 3419 if (err) 3420 return 0; 3421 } 3422 3423 return generic_block_bmap(mapping, block, ext4_get_block); 3424 } 3425 3426 static int ext4_readpage(struct file *file, struct page *page) 3427 { 3428 return mpage_readpage(page, ext4_get_block); 3429 } 3430 3431 static int 3432 ext4_readpages(struct file *file, struct address_space *mapping, 3433 struct list_head *pages, unsigned nr_pages) 3434 { 3435 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block); 3436 } 3437 3438 static void ext4_free_io_end(ext4_io_end_t *io) 3439 { 3440 BUG_ON(!io); 3441 if (io->page) 3442 put_page(io->page); 3443 iput(io->inode); 3444 kfree(io); 3445 } 3446 3447 static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset) 3448 { 3449 struct buffer_head *head, *bh; 3450 unsigned int curr_off = 0; 3451 3452 if (!page_has_buffers(page)) 3453 return; 3454 head = bh = page_buffers(page); 3455 do { 3456 if (offset <= curr_off && test_clear_buffer_uninit(bh) 3457 && bh->b_private) { 3458 ext4_free_io_end(bh->b_private); 3459 bh->b_private = NULL; 3460 bh->b_end_io = NULL; 3461 } 3462 curr_off = curr_off + bh->b_size; 3463 bh = bh->b_this_page; 3464 } while (bh != head); 3465 } 3466 3467 static void ext4_invalidatepage(struct page *page, unsigned long offset) 3468 { 3469 journal_t *journal = EXT4_JOURNAL(page->mapping->host); 3470 3471 /* 3472 * free any io_end structure allocated for buffers to be discarded 3473 */ 3474 if (ext4_should_dioread_nolock(page->mapping->host)) 3475 ext4_invalidatepage_free_endio(page, offset); 3476 /* 3477 * If it's a full truncate we just forget about the pending dirtying 3478 */ 3479 if (offset == 0) 3480 ClearPageChecked(page); 3481 3482 if (journal) 3483 jbd2_journal_invalidatepage(journal, page, offset); 3484 else 3485 block_invalidatepage(page, offset); 3486 } 3487 3488 static int ext4_releasepage(struct page *page, gfp_t wait) 3489 { 3490 journal_t *journal = EXT4_JOURNAL(page->mapping->host); 3491 3492 WARN_ON(PageChecked(page)); 3493 if (!page_has_buffers(page)) 3494 return 0; 3495 if (journal) 3496 return jbd2_journal_try_to_free_buffers(journal, page, wait); 3497 else 3498 return try_to_free_buffers(page); 3499 } 3500 3501 /* 3502 * O_DIRECT for ext3 (or indirect map) based files 3503 * 3504 * If the O_DIRECT write will extend the file then add this inode to the 3505 * orphan list. So recovery will truncate it back to the original size 3506 * if the machine crashes during the write. 3507 * 3508 * If the O_DIRECT write is intantiating holes inside i_size and the machine 3509 * crashes then stale disk data _may_ be exposed inside the file. But current 3510 * VFS code falls back into buffered path in that case so we are safe. 3511 */ 3512 static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb, 3513 const struct iovec *iov, loff_t offset, 3514 unsigned long nr_segs) 3515 { 3516 struct file *file = iocb->ki_filp; 3517 struct inode *inode = file->f_mapping->host; 3518 struct ext4_inode_info *ei = EXT4_I(inode); 3519 handle_t *handle; 3520 ssize_t ret; 3521 int orphan = 0; 3522 size_t count = iov_length(iov, nr_segs); 3523 int retries = 0; 3524 3525 if (rw == WRITE) { 3526 loff_t final_size = offset + count; 3527 3528 if (final_size > inode->i_size) { 3529 /* Credits for sb + inode write */ 3530 handle = ext4_journal_start(inode, 2); 3531 if (IS_ERR(handle)) { 3532 ret = PTR_ERR(handle); 3533 goto out; 3534 } 3535 ret = ext4_orphan_add(handle, inode); 3536 if (ret) { 3537 ext4_journal_stop(handle); 3538 goto out; 3539 } 3540 orphan = 1; 3541 ei->i_disksize = inode->i_size; 3542 ext4_journal_stop(handle); 3543 } 3544 } 3545 3546 retry: 3547 if (rw == READ && ext4_should_dioread_nolock(inode)) 3548 ret = blockdev_direct_IO_no_locking(rw, iocb, inode, 3549 inode->i_sb->s_bdev, iov, 3550 offset, nr_segs, 3551 ext4_get_block, NULL); 3552 else 3553 ret = blockdev_direct_IO(rw, iocb, inode, 3554 inode->i_sb->s_bdev, iov, 3555 offset, nr_segs, 3556 ext4_get_block, NULL); 3557 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) 3558 goto retry; 3559 3560 if (orphan) { 3561 int err; 3562 3563 /* Credits for sb + inode write */ 3564 handle = ext4_journal_start(inode, 2); 3565 if (IS_ERR(handle)) { 3566 /* This is really bad luck. We've written the data 3567 * but cannot extend i_size. Bail out and pretend 3568 * the write failed... */ 3569 ret = PTR_ERR(handle); 3570 if (inode->i_nlink) 3571 ext4_orphan_del(NULL, inode); 3572 3573 goto out; 3574 } 3575 if (inode->i_nlink) 3576 ext4_orphan_del(handle, inode); 3577 if (ret > 0) { 3578 loff_t end = offset + ret; 3579 if (end > inode->i_size) { 3580 ei->i_disksize = end; 3581 i_size_write(inode, end); 3582 /* 3583 * We're going to return a positive `ret' 3584 * here due to non-zero-length I/O, so there's 3585 * no way of reporting error returns from 3586 * ext4_mark_inode_dirty() to userspace. So 3587 * ignore it. 3588 */ 3589 ext4_mark_inode_dirty(handle, inode); 3590 } 3591 } 3592 err = ext4_journal_stop(handle); 3593 if (ret == 0) 3594 ret = err; 3595 } 3596 out: 3597 return ret; 3598 } 3599 3600 /* 3601 * ext4_get_block used when preparing for a DIO write or buffer write. 3602 * We allocate an uinitialized extent if blocks haven't been allocated. 3603 * The extent will be converted to initialized after the IO is complete. 3604 */ 3605 static int ext4_get_block_write(struct inode *inode, sector_t iblock, 3606 struct buffer_head *bh_result, int create) 3607 { 3608 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n", 3609 inode->i_ino, create); 3610 return _ext4_get_block(inode, iblock, bh_result, 3611 EXT4_GET_BLOCKS_IO_CREATE_EXT); 3612 } 3613 3614 static void dump_completed_IO(struct inode * inode) 3615 { 3616 #ifdef EXT4_DEBUG 3617 struct list_head *cur, *before, *after; 3618 ext4_io_end_t *io, *io0, *io1; 3619 unsigned long flags; 3620 3621 if (list_empty(&EXT4_I(inode)->i_completed_io_list)){ 3622 ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino); 3623 return; 3624 } 3625 3626 ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino); 3627 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); 3628 list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){ 3629 cur = &io->list; 3630 before = cur->prev; 3631 io0 = container_of(before, ext4_io_end_t, list); 3632 after = cur->next; 3633 io1 = container_of(after, ext4_io_end_t, list); 3634 3635 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n", 3636 io, inode->i_ino, io0, io1); 3637 } 3638 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); 3639 #endif 3640 } 3641 3642 /* 3643 * check a range of space and convert unwritten extents to written. 3644 */ 3645 static int ext4_end_io_nolock(ext4_io_end_t *io) 3646 { 3647 struct inode *inode = io->inode; 3648 loff_t offset = io->offset; 3649 ssize_t size = io->size; 3650 int ret = 0; 3651 3652 ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," 3653 "list->prev 0x%p\n", 3654 io, inode->i_ino, io->list.next, io->list.prev); 3655 3656 if (list_empty(&io->list)) 3657 return ret; 3658 3659 if (io->flag != EXT4_IO_UNWRITTEN) 3660 return ret; 3661 3662 ret = ext4_convert_unwritten_extents(inode, offset, size); 3663 if (ret < 0) { 3664 printk(KERN_EMERG "%s: failed to convert unwritten" 3665 "extents to written extents, error is %d" 3666 " io is still on inode %lu aio dio list\n", 3667 __func__, ret, inode->i_ino); 3668 return ret; 3669 } 3670 3671 /* clear the DIO AIO unwritten flag */ 3672 io->flag = 0; 3673 return ret; 3674 } 3675 3676 /* 3677 * work on completed aio dio IO, to convert unwritten extents to extents 3678 */ 3679 static void ext4_end_io_work(struct work_struct *work) 3680 { 3681 ext4_io_end_t *io = container_of(work, ext4_io_end_t, work); 3682 struct inode *inode = io->inode; 3683 struct ext4_inode_info *ei = EXT4_I(inode); 3684 unsigned long flags; 3685 int ret; 3686 3687 mutex_lock(&inode->i_mutex); 3688 ret = ext4_end_io_nolock(io); 3689 if (ret < 0) { 3690 mutex_unlock(&inode->i_mutex); 3691 return; 3692 } 3693 3694 spin_lock_irqsave(&ei->i_completed_io_lock, flags); 3695 if (!list_empty(&io->list)) 3696 list_del_init(&io->list); 3697 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 3698 mutex_unlock(&inode->i_mutex); 3699 ext4_free_io_end(io); 3700 } 3701 3702 /* 3703 * This function is called from ext4_sync_file(). 3704 * 3705 * When IO is completed, the work to convert unwritten extents to 3706 * written is queued on workqueue but may not get immediately 3707 * scheduled. When fsync is called, we need to ensure the 3708 * conversion is complete before fsync returns. 3709 * The inode keeps track of a list of pending/completed IO that 3710 * might needs to do the conversion. This function walks through 3711 * the list and convert the related unwritten extents for completed IO 3712 * to written. 3713 * The function return the number of pending IOs on success. 3714 */ 3715 int flush_completed_IO(struct inode *inode) 3716 { 3717 ext4_io_end_t *io; 3718 struct ext4_inode_info *ei = EXT4_I(inode); 3719 unsigned long flags; 3720 int ret = 0; 3721 int ret2 = 0; 3722 3723 if (list_empty(&ei->i_completed_io_list)) 3724 return ret; 3725 3726 dump_completed_IO(inode); 3727 spin_lock_irqsave(&ei->i_completed_io_lock, flags); 3728 while (!list_empty(&ei->i_completed_io_list)){ 3729 io = list_entry(ei->i_completed_io_list.next, 3730 ext4_io_end_t, list); 3731 /* 3732 * Calling ext4_end_io_nolock() to convert completed 3733 * IO to written. 3734 * 3735 * When ext4_sync_file() is called, run_queue() may already 3736 * about to flush the work corresponding to this io structure. 3737 * It will be upset if it founds the io structure related 3738 * to the work-to-be schedule is freed. 3739 * 3740 * Thus we need to keep the io structure still valid here after 3741 * convertion finished. The io structure has a flag to 3742 * avoid double converting from both fsync and background work 3743 * queue work. 3744 */ 3745 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 3746 ret = ext4_end_io_nolock(io); 3747 spin_lock_irqsave(&ei->i_completed_io_lock, flags); 3748 if (ret < 0) 3749 ret2 = ret; 3750 else 3751 list_del_init(&io->list); 3752 } 3753 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 3754 return (ret2 < 0) ? ret2 : 0; 3755 } 3756 3757 static ext4_io_end_t *ext4_init_io_end (struct inode *inode, gfp_t flags) 3758 { 3759 ext4_io_end_t *io = NULL; 3760 3761 io = kmalloc(sizeof(*io), flags); 3762 3763 if (io) { 3764 igrab(inode); 3765 io->inode = inode; 3766 io->flag = 0; 3767 io->offset = 0; 3768 io->size = 0; 3769 io->page = NULL; 3770 INIT_WORK(&io->work, ext4_end_io_work); 3771 INIT_LIST_HEAD(&io->list); 3772 } 3773 3774 return io; 3775 } 3776 3777 static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, 3778 ssize_t size, void *private) 3779 { 3780 ext4_io_end_t *io_end = iocb->private; 3781 struct workqueue_struct *wq; 3782 unsigned long flags; 3783 struct ext4_inode_info *ei; 3784 3785 /* if not async direct IO or dio with 0 bytes write, just return */ 3786 if (!io_end || !size) 3787 return; 3788 3789 ext_debug("ext4_end_io_dio(): io_end 0x%p" 3790 "for inode %lu, iocb 0x%p, offset %llu, size %llu\n", 3791 iocb->private, io_end->inode->i_ino, iocb, offset, 3792 size); 3793 3794 /* if not aio dio with unwritten extents, just free io and return */ 3795 if (io_end->flag != EXT4_IO_UNWRITTEN){ 3796 ext4_free_io_end(io_end); 3797 iocb->private = NULL; 3798 return; 3799 } 3800 3801 io_end->offset = offset; 3802 io_end->size = size; 3803 io_end->flag = EXT4_IO_UNWRITTEN; 3804 wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq; 3805 3806 /* queue the work to convert unwritten extents to written */ 3807 queue_work(wq, &io_end->work); 3808 3809 /* Add the io_end to per-inode completed aio dio list*/ 3810 ei = EXT4_I(io_end->inode); 3811 spin_lock_irqsave(&ei->i_completed_io_lock, flags); 3812 list_add_tail(&io_end->list, &ei->i_completed_io_list); 3813 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 3814 iocb->private = NULL; 3815 } 3816 3817 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate) 3818 { 3819 ext4_io_end_t *io_end = bh->b_private; 3820 struct workqueue_struct *wq; 3821 struct inode *inode; 3822 unsigned long flags; 3823 3824 if (!test_clear_buffer_uninit(bh) || !io_end) 3825 goto out; 3826 3827 if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) { 3828 printk("sb umounted, discard end_io request for inode %lu\n", 3829 io_end->inode->i_ino); 3830 ext4_free_io_end(io_end); 3831 goto out; 3832 } 3833 3834 io_end->flag = EXT4_IO_UNWRITTEN; 3835 inode = io_end->inode; 3836 3837 /* Add the io_end to per-inode completed io list*/ 3838 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); 3839 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); 3840 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); 3841 3842 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; 3843 /* queue the work to convert unwritten extents to written */ 3844 queue_work(wq, &io_end->work); 3845 out: 3846 bh->b_private = NULL; 3847 bh->b_end_io = NULL; 3848 clear_buffer_uninit(bh); 3849 end_buffer_async_write(bh, uptodate); 3850 } 3851 3852 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode) 3853 { 3854 ext4_io_end_t *io_end; 3855 struct page *page = bh->b_page; 3856 loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT; 3857 size_t size = bh->b_size; 3858 3859 retry: 3860 io_end = ext4_init_io_end(inode, GFP_ATOMIC); 3861 if (!io_end) { 3862 if (printk_ratelimit()) 3863 printk(KERN_WARNING "%s: allocation fail\n", __func__); 3864 schedule(); 3865 goto retry; 3866 } 3867 io_end->offset = offset; 3868 io_end->size = size; 3869 /* 3870 * We need to hold a reference to the page to make sure it 3871 * doesn't get evicted before ext4_end_io_work() has a chance 3872 * to convert the extent from written to unwritten. 3873 */ 3874 io_end->page = page; 3875 get_page(io_end->page); 3876 3877 bh->b_private = io_end; 3878 bh->b_end_io = ext4_end_io_buffer_write; 3879 return 0; 3880 } 3881 3882 /* 3883 * For ext4 extent files, ext4 will do direct-io write to holes, 3884 * preallocated extents, and those write extend the file, no need to 3885 * fall back to buffered IO. 3886 * 3887 * For holes, we fallocate those blocks, mark them as unintialized 3888 * If those blocks were preallocated, we mark sure they are splited, but 3889 * still keep the range to write as unintialized. 3890 * 3891 * The unwrritten extents will be converted to written when DIO is completed. 3892 * For async direct IO, since the IO may still pending when return, we 3893 * set up an end_io call back function, which will do the convertion 3894 * when async direct IO completed. 3895 * 3896 * If the O_DIRECT write will extend the file then add this inode to the 3897 * orphan list. So recovery will truncate it back to the original size 3898 * if the machine crashes during the write. 3899 * 3900 */ 3901 static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, 3902 const struct iovec *iov, loff_t offset, 3903 unsigned long nr_segs) 3904 { 3905 struct file *file = iocb->ki_filp; 3906 struct inode *inode = file->f_mapping->host; 3907 ssize_t ret; 3908 size_t count = iov_length(iov, nr_segs); 3909 3910 loff_t final_size = offset + count; 3911 if (rw == WRITE && final_size <= inode->i_size) { 3912 /* 3913 * We could direct write to holes and fallocate. 3914 * 3915 * Allocated blocks to fill the hole are marked as uninitialized 3916 * to prevent paralel buffered read to expose the stale data 3917 * before DIO complete the data IO. 3918 * 3919 * As to previously fallocated extents, ext4 get_block 3920 * will just simply mark the buffer mapped but still 3921 * keep the extents uninitialized. 3922 * 3923 * for non AIO case, we will convert those unwritten extents 3924 * to written after return back from blockdev_direct_IO. 3925 * 3926 * for async DIO, the conversion needs to be defered when 3927 * the IO is completed. The ext4 end_io callback function 3928 * will be called to take care of the conversion work. 3929 * Here for async case, we allocate an io_end structure to 3930 * hook to the iocb. 3931 */ 3932 iocb->private = NULL; 3933 EXT4_I(inode)->cur_aio_dio = NULL; 3934 if (!is_sync_kiocb(iocb)) { 3935 iocb->private = ext4_init_io_end(inode, GFP_NOFS); 3936 if (!iocb->private) 3937 return -ENOMEM; 3938 /* 3939 * we save the io structure for current async 3940 * direct IO, so that later ext4_get_blocks() 3941 * could flag the io structure whether there 3942 * is a unwritten extents needs to be converted 3943 * when IO is completed. 3944 */ 3945 EXT4_I(inode)->cur_aio_dio = iocb->private; 3946 } 3947 3948 ret = blockdev_direct_IO(rw, iocb, inode, 3949 inode->i_sb->s_bdev, iov, 3950 offset, nr_segs, 3951 ext4_get_block_write, 3952 ext4_end_io_dio); 3953 if (iocb->private) 3954 EXT4_I(inode)->cur_aio_dio = NULL; 3955 /* 3956 * The io_end structure takes a reference to the inode, 3957 * that structure needs to be destroyed and the 3958 * reference to the inode need to be dropped, when IO is 3959 * complete, even with 0 byte write, or failed. 3960 * 3961 * In the successful AIO DIO case, the io_end structure will be 3962 * desctroyed and the reference to the inode will be dropped 3963 * after the end_io call back function is called. 3964 * 3965 * In the case there is 0 byte write, or error case, since 3966 * VFS direct IO won't invoke the end_io call back function, 3967 * we need to free the end_io structure here. 3968 */ 3969 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) { 3970 ext4_free_io_end(iocb->private); 3971 iocb->private = NULL; 3972 } else if (ret > 0 && ext4_test_inode_state(inode, 3973 EXT4_STATE_DIO_UNWRITTEN)) { 3974 int err; 3975 /* 3976 * for non AIO case, since the IO is already 3977 * completed, we could do the convertion right here 3978 */ 3979 err = ext4_convert_unwritten_extents(inode, 3980 offset, ret); 3981 if (err < 0) 3982 ret = err; 3983 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); 3984 } 3985 return ret; 3986 } 3987 3988 /* for write the the end of file case, we fall back to old way */ 3989 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); 3990 } 3991 3992 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb, 3993 const struct iovec *iov, loff_t offset, 3994 unsigned long nr_segs) 3995 { 3996 struct file *file = iocb->ki_filp; 3997 struct inode *inode = file->f_mapping->host; 3998 3999 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) 4000 return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs); 4001 4002 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); 4003 } 4004 4005 /* 4006 * Pages can be marked dirty completely asynchronously from ext4's journalling 4007 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do 4008 * much here because ->set_page_dirty is called under VFS locks. The page is 4009 * not necessarily locked. 4010 * 4011 * We cannot just dirty the page and leave attached buffers clean, because the 4012 * buffers' dirty state is "definitive". We cannot just set the buffers dirty 4013 * or jbddirty because all the journalling code will explode. 4014 * 4015 * So what we do is to mark the page "pending dirty" and next time writepage 4016 * is called, propagate that into the buffers appropriately. 4017 */ 4018 static int ext4_journalled_set_page_dirty(struct page *page) 4019 { 4020 SetPageChecked(page); 4021 return __set_page_dirty_nobuffers(page); 4022 } 4023 4024 static const struct address_space_operations ext4_ordered_aops = { 4025 .readpage = ext4_readpage, 4026 .readpages = ext4_readpages, 4027 .writepage = ext4_writepage, 4028 .sync_page = block_sync_page, 4029 .write_begin = ext4_write_begin, 4030 .write_end = ext4_ordered_write_end, 4031 .bmap = ext4_bmap, 4032 .invalidatepage = ext4_invalidatepage, 4033 .releasepage = ext4_releasepage, 4034 .direct_IO = ext4_direct_IO, 4035 .migratepage = buffer_migrate_page, 4036 .is_partially_uptodate = block_is_partially_uptodate, 4037 .error_remove_page = generic_error_remove_page, 4038 }; 4039 4040 static const struct address_space_operations ext4_writeback_aops = { 4041 .readpage = ext4_readpage, 4042 .readpages = ext4_readpages, 4043 .writepage = ext4_writepage, 4044 .sync_page = block_sync_page, 4045 .write_begin = ext4_write_begin, 4046 .write_end = ext4_writeback_write_end, 4047 .bmap = ext4_bmap, 4048 .invalidatepage = ext4_invalidatepage, 4049 .releasepage = ext4_releasepage, 4050 .direct_IO = ext4_direct_IO, 4051 .migratepage = buffer_migrate_page, 4052 .is_partially_uptodate = block_is_partially_uptodate, 4053 .error_remove_page = generic_error_remove_page, 4054 }; 4055 4056 static const struct address_space_operations ext4_journalled_aops = { 4057 .readpage = ext4_readpage, 4058 .readpages = ext4_readpages, 4059 .writepage = ext4_writepage, 4060 .sync_page = block_sync_page, 4061 .write_begin = ext4_write_begin, 4062 .write_end = ext4_journalled_write_end, 4063 .set_page_dirty = ext4_journalled_set_page_dirty, 4064 .bmap = ext4_bmap, 4065 .invalidatepage = ext4_invalidatepage, 4066 .releasepage = ext4_releasepage, 4067 .is_partially_uptodate = block_is_partially_uptodate, 4068 .error_remove_page = generic_error_remove_page, 4069 }; 4070 4071 static const struct address_space_operations ext4_da_aops = { 4072 .readpage = ext4_readpage, 4073 .readpages = ext4_readpages, 4074 .writepage = ext4_writepage, 4075 .writepages = ext4_da_writepages, 4076 .sync_page = block_sync_page, 4077 .write_begin = ext4_da_write_begin, 4078 .write_end = ext4_da_write_end, 4079 .bmap = ext4_bmap, 4080 .invalidatepage = ext4_da_invalidatepage, 4081 .releasepage = ext4_releasepage, 4082 .direct_IO = ext4_direct_IO, 4083 .migratepage = buffer_migrate_page, 4084 .is_partially_uptodate = block_is_partially_uptodate, 4085 .error_remove_page = generic_error_remove_page, 4086 }; 4087 4088 void ext4_set_aops(struct inode *inode) 4089 { 4090 if (ext4_should_order_data(inode) && 4091 test_opt(inode->i_sb, DELALLOC)) 4092 inode->i_mapping->a_ops = &ext4_da_aops; 4093 else if (ext4_should_order_data(inode)) 4094 inode->i_mapping->a_ops = &ext4_ordered_aops; 4095 else if (ext4_should_writeback_data(inode) && 4096 test_opt(inode->i_sb, DELALLOC)) 4097 inode->i_mapping->a_ops = &ext4_da_aops; 4098 else if (ext4_should_writeback_data(inode)) 4099 inode->i_mapping->a_ops = &ext4_writeback_aops; 4100 else 4101 inode->i_mapping->a_ops = &ext4_journalled_aops; 4102 } 4103 4104 /* 4105 * ext4_block_truncate_page() zeroes out a mapping from file offset `from' 4106 * up to the end of the block which corresponds to `from'. 4107 * This required during truncate. We need to physically zero the tail end 4108 * of that block so it doesn't yield old data if the file is later grown. 4109 */ 4110 int ext4_block_truncate_page(handle_t *handle, 4111 struct address_space *mapping, loff_t from) 4112 { 4113 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; 4114 unsigned offset = from & (PAGE_CACHE_SIZE-1); 4115 unsigned blocksize, length, pos; 4116 ext4_lblk_t iblock; 4117 struct inode *inode = mapping->host; 4118 struct buffer_head *bh; 4119 struct page *page; 4120 int err = 0; 4121 4122 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT, 4123 mapping_gfp_mask(mapping) & ~__GFP_FS); 4124 if (!page) 4125 return -EINVAL; 4126 4127 blocksize = inode->i_sb->s_blocksize; 4128 length = blocksize - (offset & (blocksize - 1)); 4129 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); 4130 4131 /* 4132 * For "nobh" option, we can only work if we don't need to 4133 * read-in the page - otherwise we create buffers to do the IO. 4134 */ 4135 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) && 4136 ext4_should_writeback_data(inode) && PageUptodate(page)) { 4137 zero_user(page, offset, length); 4138 set_page_dirty(page); 4139 goto unlock; 4140 } 4141 4142 if (!page_has_buffers(page)) 4143 create_empty_buffers(page, blocksize, 0); 4144 4145 /* Find the buffer that contains "offset" */ 4146 bh = page_buffers(page); 4147 pos = blocksize; 4148 while (offset >= pos) { 4149 bh = bh->b_this_page; 4150 iblock++; 4151 pos += blocksize; 4152 } 4153 4154 err = 0; 4155 if (buffer_freed(bh)) { 4156 BUFFER_TRACE(bh, "freed: skip"); 4157 goto unlock; 4158 } 4159 4160 if (!buffer_mapped(bh)) { 4161 BUFFER_TRACE(bh, "unmapped"); 4162 ext4_get_block(inode, iblock, bh, 0); 4163 /* unmapped? It's a hole - nothing to do */ 4164 if (!buffer_mapped(bh)) { 4165 BUFFER_TRACE(bh, "still unmapped"); 4166 goto unlock; 4167 } 4168 } 4169 4170 /* Ok, it's mapped. Make sure it's up-to-date */ 4171 if (PageUptodate(page)) 4172 set_buffer_uptodate(bh); 4173 4174 if (!buffer_uptodate(bh)) { 4175 err = -EIO; 4176 ll_rw_block(READ, 1, &bh); 4177 wait_on_buffer(bh); 4178 /* Uhhuh. Read error. Complain and punt. */ 4179 if (!buffer_uptodate(bh)) 4180 goto unlock; 4181 } 4182 4183 if (ext4_should_journal_data(inode)) { 4184 BUFFER_TRACE(bh, "get write access"); 4185 err = ext4_journal_get_write_access(handle, bh); 4186 if (err) 4187 goto unlock; 4188 } 4189 4190 zero_user(page, offset, length); 4191 4192 BUFFER_TRACE(bh, "zeroed end of block"); 4193 4194 err = 0; 4195 if (ext4_should_journal_data(inode)) { 4196 err = ext4_handle_dirty_metadata(handle, inode, bh); 4197 } else { 4198 if (ext4_should_order_data(inode)) 4199 err = ext4_jbd2_file_inode(handle, inode); 4200 mark_buffer_dirty(bh); 4201 } 4202 4203 unlock: 4204 unlock_page(page); 4205 page_cache_release(page); 4206 return err; 4207 } 4208 4209 /* 4210 * Probably it should be a library function... search for first non-zero word 4211 * or memcmp with zero_page, whatever is better for particular architecture. 4212 * Linus? 4213 */ 4214 static inline int all_zeroes(__le32 *p, __le32 *q) 4215 { 4216 while (p < q) 4217 if (*p++) 4218 return 0; 4219 return 1; 4220 } 4221 4222 /** 4223 * ext4_find_shared - find the indirect blocks for partial truncation. 4224 * @inode: inode in question 4225 * @depth: depth of the affected branch 4226 * @offsets: offsets of pointers in that branch (see ext4_block_to_path) 4227 * @chain: place to store the pointers to partial indirect blocks 4228 * @top: place to the (detached) top of branch 4229 * 4230 * This is a helper function used by ext4_truncate(). 4231 * 4232 * When we do truncate() we may have to clean the ends of several 4233 * indirect blocks but leave the blocks themselves alive. Block is 4234 * partially truncated if some data below the new i_size is refered 4235 * from it (and it is on the path to the first completely truncated 4236 * data block, indeed). We have to free the top of that path along 4237 * with everything to the right of the path. Since no allocation 4238 * past the truncation point is possible until ext4_truncate() 4239 * finishes, we may safely do the latter, but top of branch may 4240 * require special attention - pageout below the truncation point 4241 * might try to populate it. 4242 * 4243 * We atomically detach the top of branch from the tree, store the 4244 * block number of its root in *@top, pointers to buffer_heads of 4245 * partially truncated blocks - in @chain[].bh and pointers to 4246 * their last elements that should not be removed - in 4247 * @chain[].p. Return value is the pointer to last filled element 4248 * of @chain. 4249 * 4250 * The work left to caller to do the actual freeing of subtrees: 4251 * a) free the subtree starting from *@top 4252 * b) free the subtrees whose roots are stored in 4253 * (@chain[i].p+1 .. end of @chain[i].bh->b_data) 4254 * c) free the subtrees growing from the inode past the @chain[0]. 4255 * (no partially truncated stuff there). */ 4256 4257 static Indirect *ext4_find_shared(struct inode *inode, int depth, 4258 ext4_lblk_t offsets[4], Indirect chain[4], 4259 __le32 *top) 4260 { 4261 Indirect *partial, *p; 4262 int k, err; 4263 4264 *top = 0; 4265 /* Make k index the deepest non-null offset + 1 */ 4266 for (k = depth; k > 1 && !offsets[k-1]; k--) 4267 ; 4268 partial = ext4_get_branch(inode, k, offsets, chain, &err); 4269 /* Writer: pointers */ 4270 if (!partial) 4271 partial = chain + k-1; 4272 /* 4273 * If the branch acquired continuation since we've looked at it - 4274 * fine, it should all survive and (new) top doesn't belong to us. 4275 */ 4276 if (!partial->key && *partial->p) 4277 /* Writer: end */ 4278 goto no_top; 4279 for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--) 4280 ; 4281 /* 4282 * OK, we've found the last block that must survive. The rest of our 4283 * branch should be detached before unlocking. However, if that rest 4284 * of branch is all ours and does not grow immediately from the inode 4285 * it's easier to cheat and just decrement partial->p. 4286 */ 4287 if (p == chain + k - 1 && p > chain) { 4288 p->p--; 4289 } else { 4290 *top = *p->p; 4291 /* Nope, don't do this in ext4. Must leave the tree intact */ 4292 #if 0 4293 *p->p = 0; 4294 #endif 4295 } 4296 /* Writer: end */ 4297 4298 while (partial > p) { 4299 brelse(partial->bh); 4300 partial--; 4301 } 4302 no_top: 4303 return partial; 4304 } 4305 4306 /* 4307 * Zero a number of block pointers in either an inode or an indirect block. 4308 * If we restart the transaction we must again get write access to the 4309 * indirect block for further modification. 4310 * 4311 * We release `count' blocks on disk, but (last - first) may be greater 4312 * than `count' because there can be holes in there. 4313 */ 4314 static int ext4_clear_blocks(handle_t *handle, struct inode *inode, 4315 struct buffer_head *bh, 4316 ext4_fsblk_t block_to_free, 4317 unsigned long count, __le32 *first, 4318 __le32 *last) 4319 { 4320 __le32 *p; 4321 int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED; 4322 4323 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) 4324 flags |= EXT4_FREE_BLOCKS_METADATA; 4325 4326 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free, 4327 count)) { 4328 EXT4_ERROR_INODE(inode, "attempt to clear invalid " 4329 "blocks %llu len %lu", 4330 (unsigned long long) block_to_free, count); 4331 return 1; 4332 } 4333 4334 if (try_to_extend_transaction(handle, inode)) { 4335 if (bh) { 4336 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); 4337 ext4_handle_dirty_metadata(handle, inode, bh); 4338 } 4339 ext4_mark_inode_dirty(handle, inode); 4340 ext4_truncate_restart_trans(handle, inode, 4341 blocks_for_truncate(inode)); 4342 if (bh) { 4343 BUFFER_TRACE(bh, "retaking write access"); 4344 ext4_journal_get_write_access(handle, bh); 4345 } 4346 } 4347 4348 for (p = first; p < last; p++) 4349 *p = 0; 4350 4351 ext4_free_blocks(handle, inode, 0, block_to_free, count, flags); 4352 return 0; 4353 } 4354 4355 /** 4356 * ext4_free_data - free a list of data blocks 4357 * @handle: handle for this transaction 4358 * @inode: inode we are dealing with 4359 * @this_bh: indirect buffer_head which contains *@first and *@last 4360 * @first: array of block numbers 4361 * @last: points immediately past the end of array 4362 * 4363 * We are freeing all blocks refered from that array (numbers are stored as 4364 * little-endian 32-bit) and updating @inode->i_blocks appropriately. 4365 * 4366 * We accumulate contiguous runs of blocks to free. Conveniently, if these 4367 * blocks are contiguous then releasing them at one time will only affect one 4368 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't 4369 * actually use a lot of journal space. 4370 * 4371 * @this_bh will be %NULL if @first and @last point into the inode's direct 4372 * block pointers. 4373 */ 4374 static void ext4_free_data(handle_t *handle, struct inode *inode, 4375 struct buffer_head *this_bh, 4376 __le32 *first, __le32 *last) 4377 { 4378 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */ 4379 unsigned long count = 0; /* Number of blocks in the run */ 4380 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind 4381 corresponding to 4382 block_to_free */ 4383 ext4_fsblk_t nr; /* Current block # */ 4384 __le32 *p; /* Pointer into inode/ind 4385 for current block */ 4386 int err; 4387 4388 if (this_bh) { /* For indirect block */ 4389 BUFFER_TRACE(this_bh, "get_write_access"); 4390 err = ext4_journal_get_write_access(handle, this_bh); 4391 /* Important: if we can't update the indirect pointers 4392 * to the blocks, we can't free them. */ 4393 if (err) 4394 return; 4395 } 4396 4397 for (p = first; p < last; p++) { 4398 nr = le32_to_cpu(*p); 4399 if (nr) { 4400 /* accumulate blocks to free if they're contiguous */ 4401 if (count == 0) { 4402 block_to_free = nr; 4403 block_to_free_p = p; 4404 count = 1; 4405 } else if (nr == block_to_free + count) { 4406 count++; 4407 } else { 4408 if (ext4_clear_blocks(handle, inode, this_bh, 4409 block_to_free, count, 4410 block_to_free_p, p)) 4411 break; 4412 block_to_free = nr; 4413 block_to_free_p = p; 4414 count = 1; 4415 } 4416 } 4417 } 4418 4419 if (count > 0) 4420 ext4_clear_blocks(handle, inode, this_bh, block_to_free, 4421 count, block_to_free_p, p); 4422 4423 if (this_bh) { 4424 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata"); 4425 4426 /* 4427 * The buffer head should have an attached journal head at this 4428 * point. However, if the data is corrupted and an indirect 4429 * block pointed to itself, it would have been detached when 4430 * the block was cleared. Check for this instead of OOPSing. 4431 */ 4432 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh)) 4433 ext4_handle_dirty_metadata(handle, inode, this_bh); 4434 else 4435 EXT4_ERROR_INODE(inode, 4436 "circular indirect block detected at " 4437 "block %llu", 4438 (unsigned long long) this_bh->b_blocknr); 4439 } 4440 } 4441 4442 /** 4443 * ext4_free_branches - free an array of branches 4444 * @handle: JBD handle for this transaction 4445 * @inode: inode we are dealing with 4446 * @parent_bh: the buffer_head which contains *@first and *@last 4447 * @first: array of block numbers 4448 * @last: pointer immediately past the end of array 4449 * @depth: depth of the branches to free 4450 * 4451 * We are freeing all blocks refered from these branches (numbers are 4452 * stored as little-endian 32-bit) and updating @inode->i_blocks 4453 * appropriately. 4454 */ 4455 static void ext4_free_branches(handle_t *handle, struct inode *inode, 4456 struct buffer_head *parent_bh, 4457 __le32 *first, __le32 *last, int depth) 4458 { 4459 ext4_fsblk_t nr; 4460 __le32 *p; 4461 4462 if (ext4_handle_is_aborted(handle)) 4463 return; 4464 4465 if (depth--) { 4466 struct buffer_head *bh; 4467 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); 4468 p = last; 4469 while (--p >= first) { 4470 nr = le32_to_cpu(*p); 4471 if (!nr) 4472 continue; /* A hole */ 4473 4474 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), 4475 nr, 1)) { 4476 EXT4_ERROR_INODE(inode, 4477 "invalid indirect mapped " 4478 "block %lu (level %d)", 4479 (unsigned long) nr, depth); 4480 break; 4481 } 4482 4483 /* Go read the buffer for the next level down */ 4484 bh = sb_bread(inode->i_sb, nr); 4485 4486 /* 4487 * A read failure? Report error and clear slot 4488 * (should be rare). 4489 */ 4490 if (!bh) { 4491 EXT4_ERROR_INODE(inode, 4492 "Read failure block=%llu", 4493 (unsigned long long) nr); 4494 continue; 4495 } 4496 4497 /* This zaps the entire block. Bottom up. */ 4498 BUFFER_TRACE(bh, "free child branches"); 4499 ext4_free_branches(handle, inode, bh, 4500 (__le32 *) bh->b_data, 4501 (__le32 *) bh->b_data + addr_per_block, 4502 depth); 4503 4504 /* 4505 * We've probably journalled the indirect block several 4506 * times during the truncate. But it's no longer 4507 * needed and we now drop it from the transaction via 4508 * jbd2_journal_revoke(). 4509 * 4510 * That's easy if it's exclusively part of this 4511 * transaction. But if it's part of the committing 4512 * transaction then jbd2_journal_forget() will simply 4513 * brelse() it. That means that if the underlying 4514 * block is reallocated in ext4_get_block(), 4515 * unmap_underlying_metadata() will find this block 4516 * and will try to get rid of it. damn, damn. 4517 * 4518 * If this block has already been committed to the 4519 * journal, a revoke record will be written. And 4520 * revoke records must be emitted *before* clearing 4521 * this block's bit in the bitmaps. 4522 */ 4523 ext4_forget(handle, 1, inode, bh, bh->b_blocknr); 4524 4525 /* 4526 * Everything below this this pointer has been 4527 * released. Now let this top-of-subtree go. 4528 * 4529 * We want the freeing of this indirect block to be 4530 * atomic in the journal with the updating of the 4531 * bitmap block which owns it. So make some room in 4532 * the journal. 4533 * 4534 * We zero the parent pointer *after* freeing its 4535 * pointee in the bitmaps, so if extend_transaction() 4536 * for some reason fails to put the bitmap changes and 4537 * the release into the same transaction, recovery 4538 * will merely complain about releasing a free block, 4539 * rather than leaking blocks. 4540 */ 4541 if (ext4_handle_is_aborted(handle)) 4542 return; 4543 if (try_to_extend_transaction(handle, inode)) { 4544 ext4_mark_inode_dirty(handle, inode); 4545 ext4_truncate_restart_trans(handle, inode, 4546 blocks_for_truncate(inode)); 4547 } 4548 4549 ext4_free_blocks(handle, inode, 0, nr, 1, 4550 EXT4_FREE_BLOCKS_METADATA); 4551 4552 if (parent_bh) { 4553 /* 4554 * The block which we have just freed is 4555 * pointed to by an indirect block: journal it 4556 */ 4557 BUFFER_TRACE(parent_bh, "get_write_access"); 4558 if (!ext4_journal_get_write_access(handle, 4559 parent_bh)){ 4560 *p = 0; 4561 BUFFER_TRACE(parent_bh, 4562 "call ext4_handle_dirty_metadata"); 4563 ext4_handle_dirty_metadata(handle, 4564 inode, 4565 parent_bh); 4566 } 4567 } 4568 } 4569 } else { 4570 /* We have reached the bottom of the tree. */ 4571 BUFFER_TRACE(parent_bh, "free data blocks"); 4572 ext4_free_data(handle, inode, parent_bh, first, last); 4573 } 4574 } 4575 4576 int ext4_can_truncate(struct inode *inode) 4577 { 4578 if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) 4579 return 0; 4580 if (S_ISREG(inode->i_mode)) 4581 return 1; 4582 if (S_ISDIR(inode->i_mode)) 4583 return 1; 4584 if (S_ISLNK(inode->i_mode)) 4585 return !ext4_inode_is_fast_symlink(inode); 4586 return 0; 4587 } 4588 4589 /* 4590 * ext4_truncate() 4591 * 4592 * We block out ext4_get_block() block instantiations across the entire 4593 * transaction, and VFS/VM ensures that ext4_truncate() cannot run 4594 * simultaneously on behalf of the same inode. 4595 * 4596 * As we work through the truncate and commmit bits of it to the journal there 4597 * is one core, guiding principle: the file's tree must always be consistent on 4598 * disk. We must be able to restart the truncate after a crash. 4599 * 4600 * The file's tree may be transiently inconsistent in memory (although it 4601 * probably isn't), but whenever we close off and commit a journal transaction, 4602 * the contents of (the filesystem + the journal) must be consistent and 4603 * restartable. It's pretty simple, really: bottom up, right to left (although 4604 * left-to-right works OK too). 4605 * 4606 * Note that at recovery time, journal replay occurs *before* the restart of 4607 * truncate against the orphan inode list. 4608 * 4609 * The committed inode has the new, desired i_size (which is the same as 4610 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see 4611 * that this inode's truncate did not complete and it will again call 4612 * ext4_truncate() to have another go. So there will be instantiated blocks 4613 * to the right of the truncation point in a crashed ext4 filesystem. But 4614 * that's fine - as long as they are linked from the inode, the post-crash 4615 * ext4_truncate() run will find them and release them. 4616 */ 4617 void ext4_truncate(struct inode *inode) 4618 { 4619 handle_t *handle; 4620 struct ext4_inode_info *ei = EXT4_I(inode); 4621 __le32 *i_data = ei->i_data; 4622 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); 4623 struct address_space *mapping = inode->i_mapping; 4624 ext4_lblk_t offsets[4]; 4625 Indirect chain[4]; 4626 Indirect *partial; 4627 __le32 nr = 0; 4628 int n; 4629 ext4_lblk_t last_block; 4630 unsigned blocksize = inode->i_sb->s_blocksize; 4631 4632 if (!ext4_can_truncate(inode)) 4633 return; 4634 4635 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); 4636 4637 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC)) 4638 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); 4639 4640 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { 4641 ext4_ext_truncate(inode); 4642 return; 4643 } 4644 4645 handle = start_transaction(inode); 4646 if (IS_ERR(handle)) 4647 return; /* AKPM: return what? */ 4648 4649 last_block = (inode->i_size + blocksize-1) 4650 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); 4651 4652 if (inode->i_size & (blocksize - 1)) 4653 if (ext4_block_truncate_page(handle, mapping, inode->i_size)) 4654 goto out_stop; 4655 4656 n = ext4_block_to_path(inode, last_block, offsets, NULL); 4657 if (n == 0) 4658 goto out_stop; /* error */ 4659 4660 /* 4661 * OK. This truncate is going to happen. We add the inode to the 4662 * orphan list, so that if this truncate spans multiple transactions, 4663 * and we crash, we will resume the truncate when the filesystem 4664 * recovers. It also marks the inode dirty, to catch the new size. 4665 * 4666 * Implication: the file must always be in a sane, consistent 4667 * truncatable state while each transaction commits. 4668 */ 4669 if (ext4_orphan_add(handle, inode)) 4670 goto out_stop; 4671 4672 /* 4673 * From here we block out all ext4_get_block() callers who want to 4674 * modify the block allocation tree. 4675 */ 4676 down_write(&ei->i_data_sem); 4677 4678 ext4_discard_preallocations(inode); 4679 4680 /* 4681 * The orphan list entry will now protect us from any crash which 4682 * occurs before the truncate completes, so it is now safe to propagate 4683 * the new, shorter inode size (held for now in i_size) into the 4684 * on-disk inode. We do this via i_disksize, which is the value which 4685 * ext4 *really* writes onto the disk inode. 4686 */ 4687 ei->i_disksize = inode->i_size; 4688 4689 if (n == 1) { /* direct blocks */ 4690 ext4_free_data(handle, inode, NULL, i_data+offsets[0], 4691 i_data + EXT4_NDIR_BLOCKS); 4692 goto do_indirects; 4693 } 4694 4695 partial = ext4_find_shared(inode, n, offsets, chain, &nr); 4696 /* Kill the top of shared branch (not detached) */ 4697 if (nr) { 4698 if (partial == chain) { 4699 /* Shared branch grows from the inode */ 4700 ext4_free_branches(handle, inode, NULL, 4701 &nr, &nr+1, (chain+n-1) - partial); 4702 *partial->p = 0; 4703 /* 4704 * We mark the inode dirty prior to restart, 4705 * and prior to stop. No need for it here. 4706 */ 4707 } else { 4708 /* Shared branch grows from an indirect block */ 4709 BUFFER_TRACE(partial->bh, "get_write_access"); 4710 ext4_free_branches(handle, inode, partial->bh, 4711 partial->p, 4712 partial->p+1, (chain+n-1) - partial); 4713 } 4714 } 4715 /* Clear the ends of indirect blocks on the shared branch */ 4716 while (partial > chain) { 4717 ext4_free_branches(handle, inode, partial->bh, partial->p + 1, 4718 (__le32*)partial->bh->b_data+addr_per_block, 4719 (chain+n-1) - partial); 4720 BUFFER_TRACE(partial->bh, "call brelse"); 4721 brelse(partial->bh); 4722 partial--; 4723 } 4724 do_indirects: 4725 /* Kill the remaining (whole) subtrees */ 4726 switch (offsets[0]) { 4727 default: 4728 nr = i_data[EXT4_IND_BLOCK]; 4729 if (nr) { 4730 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1); 4731 i_data[EXT4_IND_BLOCK] = 0; 4732 } 4733 case EXT4_IND_BLOCK: 4734 nr = i_data[EXT4_DIND_BLOCK]; 4735 if (nr) { 4736 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2); 4737 i_data[EXT4_DIND_BLOCK] = 0; 4738 } 4739 case EXT4_DIND_BLOCK: 4740 nr = i_data[EXT4_TIND_BLOCK]; 4741 if (nr) { 4742 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3); 4743 i_data[EXT4_TIND_BLOCK] = 0; 4744 } 4745 case EXT4_TIND_BLOCK: 4746 ; 4747 } 4748 4749 up_write(&ei->i_data_sem); 4750 inode->i_mtime = inode->i_ctime = ext4_current_time(inode); 4751 ext4_mark_inode_dirty(handle, inode); 4752 4753 /* 4754 * In a multi-transaction truncate, we only make the final transaction 4755 * synchronous 4756 */ 4757 if (IS_SYNC(inode)) 4758 ext4_handle_sync(handle); 4759 out_stop: 4760 /* 4761 * If this was a simple ftruncate(), and the file will remain alive 4762 * then we need to clear up the orphan record which we created above. 4763 * However, if this was a real unlink then we were called by 4764 * ext4_delete_inode(), and we allow that function to clean up the 4765 * orphan info for us. 4766 */ 4767 if (inode->i_nlink) 4768 ext4_orphan_del(handle, inode); 4769 4770 ext4_journal_stop(handle); 4771 } 4772 4773 /* 4774 * ext4_get_inode_loc returns with an extra refcount against the inode's 4775 * underlying buffer_head on success. If 'in_mem' is true, we have all 4776 * data in memory that is needed to recreate the on-disk version of this 4777 * inode. 4778 */ 4779 static int __ext4_get_inode_loc(struct inode *inode, 4780 struct ext4_iloc *iloc, int in_mem) 4781 { 4782 struct ext4_group_desc *gdp; 4783 struct buffer_head *bh; 4784 struct super_block *sb = inode->i_sb; 4785 ext4_fsblk_t block; 4786 int inodes_per_block, inode_offset; 4787 4788 iloc->bh = NULL; 4789 if (!ext4_valid_inum(sb, inode->i_ino)) 4790 return -EIO; 4791 4792 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb); 4793 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL); 4794 if (!gdp) 4795 return -EIO; 4796 4797 /* 4798 * Figure out the offset within the block group inode table 4799 */ 4800 inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb)); 4801 inode_offset = ((inode->i_ino - 1) % 4802 EXT4_INODES_PER_GROUP(sb)); 4803 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block); 4804 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb); 4805 4806 bh = sb_getblk(sb, block); 4807 if (!bh) { 4808 EXT4_ERROR_INODE(inode, "unable to read inode block - " 4809 "block %llu", block); 4810 return -EIO; 4811 } 4812 if (!buffer_uptodate(bh)) { 4813 lock_buffer(bh); 4814 4815 /* 4816 * If the buffer has the write error flag, we have failed 4817 * to write out another inode in the same block. In this 4818 * case, we don't have to read the block because we may 4819 * read the old inode data successfully. 4820 */ 4821 if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) 4822 set_buffer_uptodate(bh); 4823 4824 if (buffer_uptodate(bh)) { 4825 /* someone brought it uptodate while we waited */ 4826 unlock_buffer(bh); 4827 goto has_buffer; 4828 } 4829 4830 /* 4831 * If we have all information of the inode in memory and this 4832 * is the only valid inode in the block, we need not read the 4833 * block. 4834 */ 4835 if (in_mem) { 4836 struct buffer_head *bitmap_bh; 4837 int i, start; 4838 4839 start = inode_offset & ~(inodes_per_block - 1); 4840 4841 /* Is the inode bitmap in cache? */ 4842 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp)); 4843 if (!bitmap_bh) 4844 goto make_io; 4845 4846 /* 4847 * If the inode bitmap isn't in cache then the 4848 * optimisation may end up performing two reads instead 4849 * of one, so skip it. 4850 */ 4851 if (!buffer_uptodate(bitmap_bh)) { 4852 brelse(bitmap_bh); 4853 goto make_io; 4854 } 4855 for (i = start; i < start + inodes_per_block; i++) { 4856 if (i == inode_offset) 4857 continue; 4858 if (ext4_test_bit(i, bitmap_bh->b_data)) 4859 break; 4860 } 4861 brelse(bitmap_bh); 4862 if (i == start + inodes_per_block) { 4863 /* all other inodes are free, so skip I/O */ 4864 memset(bh->b_data, 0, bh->b_size); 4865 set_buffer_uptodate(bh); 4866 unlock_buffer(bh); 4867 goto has_buffer; 4868 } 4869 } 4870 4871 make_io: 4872 /* 4873 * If we need to do any I/O, try to pre-readahead extra 4874 * blocks from the inode table. 4875 */ 4876 if (EXT4_SB(sb)->s_inode_readahead_blks) { 4877 ext4_fsblk_t b, end, table; 4878 unsigned num; 4879 4880 table = ext4_inode_table(sb, gdp); 4881 /* s_inode_readahead_blks is always a power of 2 */ 4882 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1); 4883 if (table > b) 4884 b = table; 4885 end = b + EXT4_SB(sb)->s_inode_readahead_blks; 4886 num = EXT4_INODES_PER_GROUP(sb); 4887 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, 4888 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) 4889 num -= ext4_itable_unused_count(sb, gdp); 4890 table += num / inodes_per_block; 4891 if (end > table) 4892 end = table; 4893 while (b <= end) 4894 sb_breadahead(sb, b++); 4895 } 4896 4897 /* 4898 * There are other valid inodes in the buffer, this inode 4899 * has in-inode xattrs, or we don't have this inode in memory. 4900 * Read the block from disk. 4901 */ 4902 get_bh(bh); 4903 bh->b_end_io = end_buffer_read_sync; 4904 submit_bh(READ_META, bh); 4905 wait_on_buffer(bh); 4906 if (!buffer_uptodate(bh)) { 4907 EXT4_ERROR_INODE(inode, "unable to read inode " 4908 "block %llu", block); 4909 brelse(bh); 4910 return -EIO; 4911 } 4912 } 4913 has_buffer: 4914 iloc->bh = bh; 4915 return 0; 4916 } 4917 4918 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) 4919 { 4920 /* We have all inode data except xattrs in memory here. */ 4921 return __ext4_get_inode_loc(inode, iloc, 4922 !ext4_test_inode_state(inode, EXT4_STATE_XATTR)); 4923 } 4924 4925 void ext4_set_inode_flags(struct inode *inode) 4926 { 4927 unsigned int flags = EXT4_I(inode)->i_flags; 4928 4929 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); 4930 if (flags & EXT4_SYNC_FL) 4931 inode->i_flags |= S_SYNC; 4932 if (flags & EXT4_APPEND_FL) 4933 inode->i_flags |= S_APPEND; 4934 if (flags & EXT4_IMMUTABLE_FL) 4935 inode->i_flags |= S_IMMUTABLE; 4936 if (flags & EXT4_NOATIME_FL) 4937 inode->i_flags |= S_NOATIME; 4938 if (flags & EXT4_DIRSYNC_FL) 4939 inode->i_flags |= S_DIRSYNC; 4940 } 4941 4942 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */ 4943 void ext4_get_inode_flags(struct ext4_inode_info *ei) 4944 { 4945 unsigned int vfs_fl; 4946 unsigned long old_fl, new_fl; 4947 4948 do { 4949 vfs_fl = ei->vfs_inode.i_flags; 4950 old_fl = ei->i_flags; 4951 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL| 4952 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL| 4953 EXT4_DIRSYNC_FL); 4954 if (vfs_fl & S_SYNC) 4955 new_fl |= EXT4_SYNC_FL; 4956 if (vfs_fl & S_APPEND) 4957 new_fl |= EXT4_APPEND_FL; 4958 if (vfs_fl & S_IMMUTABLE) 4959 new_fl |= EXT4_IMMUTABLE_FL; 4960 if (vfs_fl & S_NOATIME) 4961 new_fl |= EXT4_NOATIME_FL; 4962 if (vfs_fl & S_DIRSYNC) 4963 new_fl |= EXT4_DIRSYNC_FL; 4964 } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl); 4965 } 4966 4967 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode, 4968 struct ext4_inode_info *ei) 4969 { 4970 blkcnt_t i_blocks ; 4971 struct inode *inode = &(ei->vfs_inode); 4972 struct super_block *sb = inode->i_sb; 4973 4974 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, 4975 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) { 4976 /* we are using combined 48 bit field */ 4977 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 | 4978 le32_to_cpu(raw_inode->i_blocks_lo); 4979 if (ei->i_flags & EXT4_HUGE_FILE_FL) { 4980 /* i_blocks represent file system block size */ 4981 return i_blocks << (inode->i_blkbits - 9); 4982 } else { 4983 return i_blocks; 4984 } 4985 } else { 4986 return le32_to_cpu(raw_inode->i_blocks_lo); 4987 } 4988 } 4989 4990 struct inode *ext4_iget(struct super_block *sb, unsigned long ino) 4991 { 4992 struct ext4_iloc iloc; 4993 struct ext4_inode *raw_inode; 4994 struct ext4_inode_info *ei; 4995 struct inode *inode; 4996 journal_t *journal = EXT4_SB(sb)->s_journal; 4997 long ret; 4998 int block; 4999 5000 inode = iget_locked(sb, ino); 5001 if (!inode) 5002 return ERR_PTR(-ENOMEM); 5003 if (!(inode->i_state & I_NEW)) 5004 return inode; 5005 5006 ei = EXT4_I(inode); 5007 iloc.bh = 0; 5008 5009 ret = __ext4_get_inode_loc(inode, &iloc, 0); 5010 if (ret < 0) 5011 goto bad_inode; 5012 raw_inode = ext4_raw_inode(&iloc); 5013 inode->i_mode = le16_to_cpu(raw_inode->i_mode); 5014 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); 5015 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); 5016 if (!(test_opt(inode->i_sb, NO_UID32))) { 5017 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16; 5018 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16; 5019 } 5020 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count); 5021 5022 ei->i_state_flags = 0; 5023 ei->i_dir_start_lookup = 0; 5024 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); 5025 /* We now have enough fields to check if the inode was active or not. 5026 * This is needed because nfsd might try to access dead inodes 5027 * the test is that same one that e2fsck uses 5028 * NeilBrown 1999oct15 5029 */ 5030 if (inode->i_nlink == 0) { 5031 if (inode->i_mode == 0 || 5032 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) { 5033 /* this inode is deleted */ 5034 ret = -ESTALE; 5035 goto bad_inode; 5036 } 5037 /* The only unlinked inodes we let through here have 5038 * valid i_mode and are being read by the orphan 5039 * recovery code: that's fine, we're about to complete 5040 * the process of deleting those. */ 5041 } 5042 ei->i_flags = le32_to_cpu(raw_inode->i_flags); 5043 inode->i_blocks = ext4_inode_blocks(raw_inode, ei); 5044 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo); 5045 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) 5046 ei->i_file_acl |= 5047 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32; 5048 inode->i_size = ext4_isize(raw_inode); 5049 ei->i_disksize = inode->i_size; 5050 #ifdef CONFIG_QUOTA 5051 ei->i_reserved_quota = 0; 5052 #endif 5053 inode->i_generation = le32_to_cpu(raw_inode->i_generation); 5054 ei->i_block_group = iloc.block_group; 5055 ei->i_last_alloc_group = ~0; 5056 /* 5057 * NOTE! The in-memory inode i_data array is in little-endian order 5058 * even on big-endian machines: we do NOT byteswap the block numbers! 5059 */ 5060 for (block = 0; block < EXT4_N_BLOCKS; block++) 5061 ei->i_data[block] = raw_inode->i_block[block]; 5062 INIT_LIST_HEAD(&ei->i_orphan); 5063 5064 /* 5065 * Set transaction id's of transactions that have to be committed 5066 * to finish f[data]sync. We set them to currently running transaction 5067 * as we cannot be sure that the inode or some of its metadata isn't 5068 * part of the transaction - the inode could have been reclaimed and 5069 * now it is reread from disk. 5070 */ 5071 if (journal) { 5072 transaction_t *transaction; 5073 tid_t tid; 5074 5075 spin_lock(&journal->j_state_lock); 5076 if (journal->j_running_transaction) 5077 transaction = journal->j_running_transaction; 5078 else 5079 transaction = journal->j_committing_transaction; 5080 if (transaction) 5081 tid = transaction->t_tid; 5082 else 5083 tid = journal->j_commit_sequence; 5084 spin_unlock(&journal->j_state_lock); 5085 ei->i_sync_tid = tid; 5086 ei->i_datasync_tid = tid; 5087 } 5088 5089 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { 5090 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize); 5091 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > 5092 EXT4_INODE_SIZE(inode->i_sb)) { 5093 ret = -EIO; 5094 goto bad_inode; 5095 } 5096 if (ei->i_extra_isize == 0) { 5097 /* The extra space is currently unused. Use it. */ 5098 ei->i_extra_isize = sizeof(struct ext4_inode) - 5099 EXT4_GOOD_OLD_INODE_SIZE; 5100 } else { 5101 __le32 *magic = (void *)raw_inode + 5102 EXT4_GOOD_OLD_INODE_SIZE + 5103 ei->i_extra_isize; 5104 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) 5105 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 5106 } 5107 } else 5108 ei->i_extra_isize = 0; 5109 5110 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode); 5111 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode); 5112 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode); 5113 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode); 5114 5115 inode->i_version = le32_to_cpu(raw_inode->i_disk_version); 5116 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { 5117 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) 5118 inode->i_version |= 5119 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32; 5120 } 5121 5122 ret = 0; 5123 if (ei->i_file_acl && 5124 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) { 5125 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu", 5126 ei->i_file_acl); 5127 ret = -EIO; 5128 goto bad_inode; 5129 } else if (ei->i_flags & EXT4_EXTENTS_FL) { 5130 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || 5131 (S_ISLNK(inode->i_mode) && 5132 !ext4_inode_is_fast_symlink(inode))) 5133 /* Validate extent which is part of inode */ 5134 ret = ext4_ext_check_inode(inode); 5135 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || 5136 (S_ISLNK(inode->i_mode) && 5137 !ext4_inode_is_fast_symlink(inode))) { 5138 /* Validate block references which are part of inode */ 5139 ret = ext4_check_inode_blockref(inode); 5140 } 5141 if (ret) 5142 goto bad_inode; 5143 5144 if (S_ISREG(inode->i_mode)) { 5145 inode->i_op = &ext4_file_inode_operations; 5146 inode->i_fop = &ext4_file_operations; 5147 ext4_set_aops(inode); 5148 } else if (S_ISDIR(inode->i_mode)) { 5149 inode->i_op = &ext4_dir_inode_operations; 5150 inode->i_fop = &ext4_dir_operations; 5151 } else if (S_ISLNK(inode->i_mode)) { 5152 if (ext4_inode_is_fast_symlink(inode)) { 5153 inode->i_op = &ext4_fast_symlink_inode_operations; 5154 nd_terminate_link(ei->i_data, inode->i_size, 5155 sizeof(ei->i_data) - 1); 5156 } else { 5157 inode->i_op = &ext4_symlink_inode_operations; 5158 ext4_set_aops(inode); 5159 } 5160 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 5161 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 5162 inode->i_op = &ext4_special_inode_operations; 5163 if (raw_inode->i_block[0]) 5164 init_special_inode(inode, inode->i_mode, 5165 old_decode_dev(le32_to_cpu(raw_inode->i_block[0]))); 5166 else 5167 init_special_inode(inode, inode->i_mode, 5168 new_decode_dev(le32_to_cpu(raw_inode->i_block[1]))); 5169 } else { 5170 ret = -EIO; 5171 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode); 5172 goto bad_inode; 5173 } 5174 brelse(iloc.bh); 5175 ext4_set_inode_flags(inode); 5176 unlock_new_inode(inode); 5177 return inode; 5178 5179 bad_inode: 5180 brelse(iloc.bh); 5181 iget_failed(inode); 5182 return ERR_PTR(ret); 5183 } 5184 5185 static int ext4_inode_blocks_set(handle_t *handle, 5186 struct ext4_inode *raw_inode, 5187 struct ext4_inode_info *ei) 5188 { 5189 struct inode *inode = &(ei->vfs_inode); 5190 u64 i_blocks = inode->i_blocks; 5191 struct super_block *sb = inode->i_sb; 5192 5193 if (i_blocks <= ~0U) { 5194 /* 5195 * i_blocks can be represnted in a 32 bit variable 5196 * as multiple of 512 bytes 5197 */ 5198 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); 5199 raw_inode->i_blocks_high = 0; 5200 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); 5201 return 0; 5202 } 5203 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) 5204 return -EFBIG; 5205 5206 if (i_blocks <= 0xffffffffffffULL) { 5207 /* 5208 * i_blocks can be represented in a 48 bit variable 5209 * as multiple of 512 bytes 5210 */ 5211 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); 5212 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); 5213 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); 5214 } else { 5215 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE); 5216 /* i_block is stored in file system block size */ 5217 i_blocks = i_blocks >> (inode->i_blkbits - 9); 5218 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); 5219 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); 5220 } 5221 return 0; 5222 } 5223 5224 /* 5225 * Post the struct inode info into an on-disk inode location in the 5226 * buffer-cache. This gobbles the caller's reference to the 5227 * buffer_head in the inode location struct. 5228 * 5229 * The caller must have write access to iloc->bh. 5230 */ 5231 static int ext4_do_update_inode(handle_t *handle, 5232 struct inode *inode, 5233 struct ext4_iloc *iloc) 5234 { 5235 struct ext4_inode *raw_inode = ext4_raw_inode(iloc); 5236 struct ext4_inode_info *ei = EXT4_I(inode); 5237 struct buffer_head *bh = iloc->bh; 5238 int err = 0, rc, block; 5239 5240 /* For fields not not tracking in the in-memory inode, 5241 * initialise them to zero for new inodes. */ 5242 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) 5243 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 5244 5245 ext4_get_inode_flags(ei); 5246 raw_inode->i_mode = cpu_to_le16(inode->i_mode); 5247 if (!(test_opt(inode->i_sb, NO_UID32))) { 5248 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid)); 5249 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid)); 5250 /* 5251 * Fix up interoperability with old kernels. Otherwise, old inodes get 5252 * re-used with the upper 16 bits of the uid/gid intact 5253 */ 5254 if (!ei->i_dtime) { 5255 raw_inode->i_uid_high = 5256 cpu_to_le16(high_16_bits(inode->i_uid)); 5257 raw_inode->i_gid_high = 5258 cpu_to_le16(high_16_bits(inode->i_gid)); 5259 } else { 5260 raw_inode->i_uid_high = 0; 5261 raw_inode->i_gid_high = 0; 5262 } 5263 } else { 5264 raw_inode->i_uid_low = 5265 cpu_to_le16(fs_high2lowuid(inode->i_uid)); 5266 raw_inode->i_gid_low = 5267 cpu_to_le16(fs_high2lowgid(inode->i_gid)); 5268 raw_inode->i_uid_high = 0; 5269 raw_inode->i_gid_high = 0; 5270 } 5271 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); 5272 5273 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode); 5274 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode); 5275 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode); 5276 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode); 5277 5278 if (ext4_inode_blocks_set(handle, raw_inode, ei)) 5279 goto out_brelse; 5280 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); 5281 raw_inode->i_flags = cpu_to_le32(ei->i_flags); 5282 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != 5283 cpu_to_le32(EXT4_OS_HURD)) 5284 raw_inode->i_file_acl_high = 5285 cpu_to_le16(ei->i_file_acl >> 32); 5286 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl); 5287 ext4_isize_set(raw_inode, ei->i_disksize); 5288 if (ei->i_disksize > 0x7fffffffULL) { 5289 struct super_block *sb = inode->i_sb; 5290 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, 5291 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) || 5292 EXT4_SB(sb)->s_es->s_rev_level == 5293 cpu_to_le32(EXT4_GOOD_OLD_REV)) { 5294 /* If this is the first large file 5295 * created, add a flag to the superblock. 5296 */ 5297 err = ext4_journal_get_write_access(handle, 5298 EXT4_SB(sb)->s_sbh); 5299 if (err) 5300 goto out_brelse; 5301 ext4_update_dynamic_rev(sb); 5302 EXT4_SET_RO_COMPAT_FEATURE(sb, 5303 EXT4_FEATURE_RO_COMPAT_LARGE_FILE); 5304 sb->s_dirt = 1; 5305 ext4_handle_sync(handle); 5306 err = ext4_handle_dirty_metadata(handle, NULL, 5307 EXT4_SB(sb)->s_sbh); 5308 } 5309 } 5310 raw_inode->i_generation = cpu_to_le32(inode->i_generation); 5311 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) { 5312 if (old_valid_dev(inode->i_rdev)) { 5313 raw_inode->i_block[0] = 5314 cpu_to_le32(old_encode_dev(inode->i_rdev)); 5315 raw_inode->i_block[1] = 0; 5316 } else { 5317 raw_inode->i_block[0] = 0; 5318 raw_inode->i_block[1] = 5319 cpu_to_le32(new_encode_dev(inode->i_rdev)); 5320 raw_inode->i_block[2] = 0; 5321 } 5322 } else 5323 for (block = 0; block < EXT4_N_BLOCKS; block++) 5324 raw_inode->i_block[block] = ei->i_data[block]; 5325 5326 raw_inode->i_disk_version = cpu_to_le32(inode->i_version); 5327 if (ei->i_extra_isize) { 5328 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) 5329 raw_inode->i_version_hi = 5330 cpu_to_le32(inode->i_version >> 32); 5331 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); 5332 } 5333 5334 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); 5335 rc = ext4_handle_dirty_metadata(handle, NULL, bh); 5336 if (!err) 5337 err = rc; 5338 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 5339 5340 ext4_update_inode_fsync_trans(handle, inode, 0); 5341 out_brelse: 5342 brelse(bh); 5343 ext4_std_error(inode->i_sb, err); 5344 return err; 5345 } 5346 5347 /* 5348 * ext4_write_inode() 5349 * 5350 * We are called from a few places: 5351 * 5352 * - Within generic_file_write() for O_SYNC files. 5353 * Here, there will be no transaction running. We wait for any running 5354 * trasnaction to commit. 5355 * 5356 * - Within sys_sync(), kupdate and such. 5357 * We wait on commit, if tol to. 5358 * 5359 * - Within prune_icache() (PF_MEMALLOC == true) 5360 * Here we simply return. We can't afford to block kswapd on the 5361 * journal commit. 5362 * 5363 * In all cases it is actually safe for us to return without doing anything, 5364 * because the inode has been copied into a raw inode buffer in 5365 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for 5366 * knfsd. 5367 * 5368 * Note that we are absolutely dependent upon all inode dirtiers doing the 5369 * right thing: they *must* call mark_inode_dirty() after dirtying info in 5370 * which we are interested. 5371 * 5372 * It would be a bug for them to not do this. The code: 5373 * 5374 * mark_inode_dirty(inode) 5375 * stuff(); 5376 * inode->i_size = expr; 5377 * 5378 * is in error because a kswapd-driven write_inode() could occur while 5379 * `stuff()' is running, and the new i_size will be lost. Plus the inode 5380 * will no longer be on the superblock's dirty inode list. 5381 */ 5382 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc) 5383 { 5384 int err; 5385 5386 if (current->flags & PF_MEMALLOC) 5387 return 0; 5388 5389 if (EXT4_SB(inode->i_sb)->s_journal) { 5390 if (ext4_journal_current_handle()) { 5391 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n"); 5392 dump_stack(); 5393 return -EIO; 5394 } 5395 5396 if (wbc->sync_mode != WB_SYNC_ALL) 5397 return 0; 5398 5399 err = ext4_force_commit(inode->i_sb); 5400 } else { 5401 struct ext4_iloc iloc; 5402 5403 err = __ext4_get_inode_loc(inode, &iloc, 0); 5404 if (err) 5405 return err; 5406 if (wbc->sync_mode == WB_SYNC_ALL) 5407 sync_dirty_buffer(iloc.bh); 5408 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) { 5409 EXT4_ERROR_INODE(inode, 5410 "IO error syncing inode (block=%llu)", 5411 (unsigned long long) iloc.bh->b_blocknr); 5412 err = -EIO; 5413 } 5414 brelse(iloc.bh); 5415 } 5416 return err; 5417 } 5418 5419 /* 5420 * ext4_setattr() 5421 * 5422 * Called from notify_change. 5423 * 5424 * We want to trap VFS attempts to truncate the file as soon as 5425 * possible. In particular, we want to make sure that when the VFS 5426 * shrinks i_size, we put the inode on the orphan list and modify 5427 * i_disksize immediately, so that during the subsequent flushing of 5428 * dirty pages and freeing of disk blocks, we can guarantee that any 5429 * commit will leave the blocks being flushed in an unused state on 5430 * disk. (On recovery, the inode will get truncated and the blocks will 5431 * be freed, so we have a strong guarantee that no future commit will 5432 * leave these blocks visible to the user.) 5433 * 5434 * Another thing we have to assure is that if we are in ordered mode 5435 * and inode is still attached to the committing transaction, we must 5436 * we start writeout of all the dirty pages which are being truncated. 5437 * This way we are sure that all the data written in the previous 5438 * transaction are already on disk (truncate waits for pages under 5439 * writeback). 5440 * 5441 * Called with inode->i_mutex down. 5442 */ 5443 int ext4_setattr(struct dentry *dentry, struct iattr *attr) 5444 { 5445 struct inode *inode = dentry->d_inode; 5446 int error, rc = 0; 5447 const unsigned int ia_valid = attr->ia_valid; 5448 5449 error = inode_change_ok(inode, attr); 5450 if (error) 5451 return error; 5452 5453 if (is_quota_modification(inode, attr)) 5454 dquot_initialize(inode); 5455 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || 5456 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) { 5457 handle_t *handle; 5458 5459 /* (user+group)*(old+new) structure, inode write (sb, 5460 * inode block, ? - but truncate inode update has it) */ 5461 handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+ 5462 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3); 5463 if (IS_ERR(handle)) { 5464 error = PTR_ERR(handle); 5465 goto err_out; 5466 } 5467 error = dquot_transfer(inode, attr); 5468 if (error) { 5469 ext4_journal_stop(handle); 5470 return error; 5471 } 5472 /* Update corresponding info in inode so that everything is in 5473 * one transaction */ 5474 if (attr->ia_valid & ATTR_UID) 5475 inode->i_uid = attr->ia_uid; 5476 if (attr->ia_valid & ATTR_GID) 5477 inode->i_gid = attr->ia_gid; 5478 error = ext4_mark_inode_dirty(handle, inode); 5479 ext4_journal_stop(handle); 5480 } 5481 5482 if (attr->ia_valid & ATTR_SIZE) { 5483 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { 5484 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 5485 5486 if (attr->ia_size > sbi->s_bitmap_maxbytes) { 5487 error = -EFBIG; 5488 goto err_out; 5489 } 5490 } 5491 } 5492 5493 if (S_ISREG(inode->i_mode) && 5494 attr->ia_valid & ATTR_SIZE && 5495 (attr->ia_size < inode->i_size || 5496 (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) { 5497 handle_t *handle; 5498 5499 handle = ext4_journal_start(inode, 3); 5500 if (IS_ERR(handle)) { 5501 error = PTR_ERR(handle); 5502 goto err_out; 5503 } 5504 5505 error = ext4_orphan_add(handle, inode); 5506 EXT4_I(inode)->i_disksize = attr->ia_size; 5507 rc = ext4_mark_inode_dirty(handle, inode); 5508 if (!error) 5509 error = rc; 5510 ext4_journal_stop(handle); 5511 5512 if (ext4_should_order_data(inode)) { 5513 error = ext4_begin_ordered_truncate(inode, 5514 attr->ia_size); 5515 if (error) { 5516 /* Do as much error cleanup as possible */ 5517 handle = ext4_journal_start(inode, 3); 5518 if (IS_ERR(handle)) { 5519 ext4_orphan_del(NULL, inode); 5520 goto err_out; 5521 } 5522 ext4_orphan_del(handle, inode); 5523 ext4_journal_stop(handle); 5524 goto err_out; 5525 } 5526 } 5527 /* ext4_truncate will clear the flag */ 5528 if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) 5529 ext4_truncate(inode); 5530 } 5531 5532 rc = inode_setattr(inode, attr); 5533 5534 /* If inode_setattr's call to ext4_truncate failed to get a 5535 * transaction handle at all, we need to clean up the in-core 5536 * orphan list manually. */ 5537 if (inode->i_nlink) 5538 ext4_orphan_del(NULL, inode); 5539 5540 if (!rc && (ia_valid & ATTR_MODE)) 5541 rc = ext4_acl_chmod(inode); 5542 5543 err_out: 5544 ext4_std_error(inode->i_sb, error); 5545 if (!error) 5546 error = rc; 5547 return error; 5548 } 5549 5550 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, 5551 struct kstat *stat) 5552 { 5553 struct inode *inode; 5554 unsigned long delalloc_blocks; 5555 5556 inode = dentry->d_inode; 5557 generic_fillattr(inode, stat); 5558 5559 /* 5560 * We can't update i_blocks if the block allocation is delayed 5561 * otherwise in the case of system crash before the real block 5562 * allocation is done, we will have i_blocks inconsistent with 5563 * on-disk file blocks. 5564 * We always keep i_blocks updated together with real 5565 * allocation. But to not confuse with user, stat 5566 * will return the blocks that include the delayed allocation 5567 * blocks for this file. 5568 */ 5569 spin_lock(&EXT4_I(inode)->i_block_reservation_lock); 5570 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks; 5571 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); 5572 5573 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; 5574 return 0; 5575 } 5576 5577 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks, 5578 int chunk) 5579 { 5580 int indirects; 5581 5582 /* if nrblocks are contiguous */ 5583 if (chunk) { 5584 /* 5585 * With N contiguous data blocks, it need at most 5586 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks 5587 * 2 dindirect blocks 5588 * 1 tindirect block 5589 */ 5590 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb); 5591 return indirects + 3; 5592 } 5593 /* 5594 * if nrblocks are not contiguous, worse case, each block touch 5595 * a indirect block, and each indirect block touch a double indirect 5596 * block, plus a triple indirect block 5597 */ 5598 indirects = nrblocks * 2 + 1; 5599 return indirects; 5600 } 5601 5602 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) 5603 { 5604 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 5605 return ext4_indirect_trans_blocks(inode, nrblocks, chunk); 5606 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk); 5607 } 5608 5609 /* 5610 * Account for index blocks, block groups bitmaps and block group 5611 * descriptor blocks if modify datablocks and index blocks 5612 * worse case, the indexs blocks spread over different block groups 5613 * 5614 * If datablocks are discontiguous, they are possible to spread over 5615 * different block groups too. If they are contiuguous, with flexbg, 5616 * they could still across block group boundary. 5617 * 5618 * Also account for superblock, inode, quota and xattr blocks 5619 */ 5620 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk) 5621 { 5622 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb); 5623 int gdpblocks; 5624 int idxblocks; 5625 int ret = 0; 5626 5627 /* 5628 * How many index blocks need to touch to modify nrblocks? 5629 * The "Chunk" flag indicating whether the nrblocks is 5630 * physically contiguous on disk 5631 * 5632 * For Direct IO and fallocate, they calls get_block to allocate 5633 * one single extent at a time, so they could set the "Chunk" flag 5634 */ 5635 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk); 5636 5637 ret = idxblocks; 5638 5639 /* 5640 * Now let's see how many group bitmaps and group descriptors need 5641 * to account 5642 */ 5643 groups = idxblocks; 5644 if (chunk) 5645 groups += 1; 5646 else 5647 groups += nrblocks; 5648 5649 gdpblocks = groups; 5650 if (groups > ngroups) 5651 groups = ngroups; 5652 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count) 5653 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count; 5654 5655 /* bitmaps and block group descriptor blocks */ 5656 ret += groups + gdpblocks; 5657 5658 /* Blocks for super block, inode, quota and xattr blocks */ 5659 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb); 5660 5661 return ret; 5662 } 5663 5664 /* 5665 * Calulate the total number of credits to reserve to fit 5666 * the modification of a single pages into a single transaction, 5667 * which may include multiple chunks of block allocations. 5668 * 5669 * This could be called via ext4_write_begin() 5670 * 5671 * We need to consider the worse case, when 5672 * one new block per extent. 5673 */ 5674 int ext4_writepage_trans_blocks(struct inode *inode) 5675 { 5676 int bpp = ext4_journal_blocks_per_page(inode); 5677 int ret; 5678 5679 ret = ext4_meta_trans_blocks(inode, bpp, 0); 5680 5681 /* Account for data blocks for journalled mode */ 5682 if (ext4_should_journal_data(inode)) 5683 ret += bpp; 5684 return ret; 5685 } 5686 5687 /* 5688 * Calculate the journal credits for a chunk of data modification. 5689 * 5690 * This is called from DIO, fallocate or whoever calling 5691 * ext4_get_blocks() to map/allocate a chunk of contiguous disk blocks. 5692 * 5693 * journal buffers for data blocks are not included here, as DIO 5694 * and fallocate do no need to journal data buffers. 5695 */ 5696 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks) 5697 { 5698 return ext4_meta_trans_blocks(inode, nrblocks, 1); 5699 } 5700 5701 /* 5702 * The caller must have previously called ext4_reserve_inode_write(). 5703 * Give this, we know that the caller already has write access to iloc->bh. 5704 */ 5705 int ext4_mark_iloc_dirty(handle_t *handle, 5706 struct inode *inode, struct ext4_iloc *iloc) 5707 { 5708 int err = 0; 5709 5710 if (test_opt(inode->i_sb, I_VERSION)) 5711 inode_inc_iversion(inode); 5712 5713 /* the do_update_inode consumes one bh->b_count */ 5714 get_bh(iloc->bh); 5715 5716 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */ 5717 err = ext4_do_update_inode(handle, inode, iloc); 5718 put_bh(iloc->bh); 5719 return err; 5720 } 5721 5722 /* 5723 * On success, We end up with an outstanding reference count against 5724 * iloc->bh. This _must_ be cleaned up later. 5725 */ 5726 5727 int 5728 ext4_reserve_inode_write(handle_t *handle, struct inode *inode, 5729 struct ext4_iloc *iloc) 5730 { 5731 int err; 5732 5733 err = ext4_get_inode_loc(inode, iloc); 5734 if (!err) { 5735 BUFFER_TRACE(iloc->bh, "get_write_access"); 5736 err = ext4_journal_get_write_access(handle, iloc->bh); 5737 if (err) { 5738 brelse(iloc->bh); 5739 iloc->bh = NULL; 5740 } 5741 } 5742 ext4_std_error(inode->i_sb, err); 5743 return err; 5744 } 5745 5746 /* 5747 * Expand an inode by new_extra_isize bytes. 5748 * Returns 0 on success or negative error number on failure. 5749 */ 5750 static int ext4_expand_extra_isize(struct inode *inode, 5751 unsigned int new_extra_isize, 5752 struct ext4_iloc iloc, 5753 handle_t *handle) 5754 { 5755 struct ext4_inode *raw_inode; 5756 struct ext4_xattr_ibody_header *header; 5757 struct ext4_xattr_entry *entry; 5758 5759 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) 5760 return 0; 5761 5762 raw_inode = ext4_raw_inode(&iloc); 5763 5764 header = IHDR(inode, raw_inode); 5765 entry = IFIRST(header); 5766 5767 /* No extended attributes present */ 5768 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) || 5769 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) { 5770 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0, 5771 new_extra_isize); 5772 EXT4_I(inode)->i_extra_isize = new_extra_isize; 5773 return 0; 5774 } 5775 5776 /* try to expand with EAs present */ 5777 return ext4_expand_extra_isize_ea(inode, new_extra_isize, 5778 raw_inode, handle); 5779 } 5780 5781 /* 5782 * What we do here is to mark the in-core inode as clean with respect to inode 5783 * dirtiness (it may still be data-dirty). 5784 * This means that the in-core inode may be reaped by prune_icache 5785 * without having to perform any I/O. This is a very good thing, 5786 * because *any* task may call prune_icache - even ones which 5787 * have a transaction open against a different journal. 5788 * 5789 * Is this cheating? Not really. Sure, we haven't written the 5790 * inode out, but prune_icache isn't a user-visible syncing function. 5791 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync) 5792 * we start and wait on commits. 5793 * 5794 * Is this efficient/effective? Well, we're being nice to the system 5795 * by cleaning up our inodes proactively so they can be reaped 5796 * without I/O. But we are potentially leaving up to five seconds' 5797 * worth of inodes floating about which prune_icache wants us to 5798 * write out. One way to fix that would be to get prune_icache() 5799 * to do a write_super() to free up some memory. It has the desired 5800 * effect. 5801 */ 5802 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) 5803 { 5804 struct ext4_iloc iloc; 5805 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 5806 static unsigned int mnt_count; 5807 int err, ret; 5808 5809 might_sleep(); 5810 err = ext4_reserve_inode_write(handle, inode, &iloc); 5811 if (ext4_handle_valid(handle) && 5812 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize && 5813 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) { 5814 /* 5815 * We need extra buffer credits since we may write into EA block 5816 * with this same handle. If journal_extend fails, then it will 5817 * only result in a minor loss of functionality for that inode. 5818 * If this is felt to be critical, then e2fsck should be run to 5819 * force a large enough s_min_extra_isize. 5820 */ 5821 if ((jbd2_journal_extend(handle, 5822 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) { 5823 ret = ext4_expand_extra_isize(inode, 5824 sbi->s_want_extra_isize, 5825 iloc, handle); 5826 if (ret) { 5827 ext4_set_inode_state(inode, 5828 EXT4_STATE_NO_EXPAND); 5829 if (mnt_count != 5830 le16_to_cpu(sbi->s_es->s_mnt_count)) { 5831 ext4_warning(inode->i_sb, 5832 "Unable to expand inode %lu. Delete" 5833 " some EAs or run e2fsck.", 5834 inode->i_ino); 5835 mnt_count = 5836 le16_to_cpu(sbi->s_es->s_mnt_count); 5837 } 5838 } 5839 } 5840 } 5841 if (!err) 5842 err = ext4_mark_iloc_dirty(handle, inode, &iloc); 5843 return err; 5844 } 5845 5846 /* 5847 * ext4_dirty_inode() is called from __mark_inode_dirty() 5848 * 5849 * We're really interested in the case where a file is being extended. 5850 * i_size has been changed by generic_commit_write() and we thus need 5851 * to include the updated inode in the current transaction. 5852 * 5853 * Also, dquot_alloc_block() will always dirty the inode when blocks 5854 * are allocated to the file. 5855 * 5856 * If the inode is marked synchronous, we don't honour that here - doing 5857 * so would cause a commit on atime updates, which we don't bother doing. 5858 * We handle synchronous inodes at the highest possible level. 5859 */ 5860 void ext4_dirty_inode(struct inode *inode) 5861 { 5862 handle_t *handle; 5863 5864 handle = ext4_journal_start(inode, 2); 5865 if (IS_ERR(handle)) 5866 goto out; 5867 5868 ext4_mark_inode_dirty(handle, inode); 5869 5870 ext4_journal_stop(handle); 5871 out: 5872 return; 5873 } 5874 5875 #if 0 5876 /* 5877 * Bind an inode's backing buffer_head into this transaction, to prevent 5878 * it from being flushed to disk early. Unlike 5879 * ext4_reserve_inode_write, this leaves behind no bh reference and 5880 * returns no iloc structure, so the caller needs to repeat the iloc 5881 * lookup to mark the inode dirty later. 5882 */ 5883 static int ext4_pin_inode(handle_t *handle, struct inode *inode) 5884 { 5885 struct ext4_iloc iloc; 5886 5887 int err = 0; 5888 if (handle) { 5889 err = ext4_get_inode_loc(inode, &iloc); 5890 if (!err) { 5891 BUFFER_TRACE(iloc.bh, "get_write_access"); 5892 err = jbd2_journal_get_write_access(handle, iloc.bh); 5893 if (!err) 5894 err = ext4_handle_dirty_metadata(handle, 5895 NULL, 5896 iloc.bh); 5897 brelse(iloc.bh); 5898 } 5899 } 5900 ext4_std_error(inode->i_sb, err); 5901 return err; 5902 } 5903 #endif 5904 5905 int ext4_change_inode_journal_flag(struct inode *inode, int val) 5906 { 5907 journal_t *journal; 5908 handle_t *handle; 5909 int err; 5910 5911 /* 5912 * We have to be very careful here: changing a data block's 5913 * journaling status dynamically is dangerous. If we write a 5914 * data block to the journal, change the status and then delete 5915 * that block, we risk forgetting to revoke the old log record 5916 * from the journal and so a subsequent replay can corrupt data. 5917 * So, first we make sure that the journal is empty and that 5918 * nobody is changing anything. 5919 */ 5920 5921 journal = EXT4_JOURNAL(inode); 5922 if (!journal) 5923 return 0; 5924 if (is_journal_aborted(journal)) 5925 return -EROFS; 5926 5927 jbd2_journal_lock_updates(journal); 5928 jbd2_journal_flush(journal); 5929 5930 /* 5931 * OK, there are no updates running now, and all cached data is 5932 * synced to disk. We are now in a completely consistent state 5933 * which doesn't have anything in the journal, and we know that 5934 * no filesystem updates are running, so it is safe to modify 5935 * the inode's in-core data-journaling state flag now. 5936 */ 5937 5938 if (val) 5939 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); 5940 else 5941 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); 5942 ext4_set_aops(inode); 5943 5944 jbd2_journal_unlock_updates(journal); 5945 5946 /* Finally we can mark the inode as dirty. */ 5947 5948 handle = ext4_journal_start(inode, 1); 5949 if (IS_ERR(handle)) 5950 return PTR_ERR(handle); 5951 5952 err = ext4_mark_inode_dirty(handle, inode); 5953 ext4_handle_sync(handle); 5954 ext4_journal_stop(handle); 5955 ext4_std_error(inode->i_sb, err); 5956 5957 return err; 5958 } 5959 5960 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh) 5961 { 5962 return !buffer_mapped(bh); 5963 } 5964 5965 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 5966 { 5967 struct page *page = vmf->page; 5968 loff_t size; 5969 unsigned long len; 5970 int ret = -EINVAL; 5971 void *fsdata; 5972 struct file *file = vma->vm_file; 5973 struct inode *inode = file->f_path.dentry->d_inode; 5974 struct address_space *mapping = inode->i_mapping; 5975 5976 /* 5977 * Get i_alloc_sem to stop truncates messing with the inode. We cannot 5978 * get i_mutex because we are already holding mmap_sem. 5979 */ 5980 down_read(&inode->i_alloc_sem); 5981 size = i_size_read(inode); 5982 if (page->mapping != mapping || size <= page_offset(page) 5983 || !PageUptodate(page)) { 5984 /* page got truncated from under us? */ 5985 goto out_unlock; 5986 } 5987 ret = 0; 5988 if (PageMappedToDisk(page)) 5989 goto out_unlock; 5990 5991 if (page->index == size >> PAGE_CACHE_SHIFT) 5992 len = size & ~PAGE_CACHE_MASK; 5993 else 5994 len = PAGE_CACHE_SIZE; 5995 5996 lock_page(page); 5997 /* 5998 * return if we have all the buffers mapped. This avoid 5999 * the need to call write_begin/write_end which does a 6000 * journal_start/journal_stop which can block and take 6001 * long time 6002 */ 6003 if (page_has_buffers(page)) { 6004 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, 6005 ext4_bh_unmapped)) { 6006 unlock_page(page); 6007 goto out_unlock; 6008 } 6009 } 6010 unlock_page(page); 6011 /* 6012 * OK, we need to fill the hole... Do write_begin write_end 6013 * to do block allocation/reservation.We are not holding 6014 * inode.i__mutex here. That allow * parallel write_begin, 6015 * write_end call. lock_page prevent this from happening 6016 * on the same page though 6017 */ 6018 ret = mapping->a_ops->write_begin(file, mapping, page_offset(page), 6019 len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 6020 if (ret < 0) 6021 goto out_unlock; 6022 ret = mapping->a_ops->write_end(file, mapping, page_offset(page), 6023 len, len, page, fsdata); 6024 if (ret < 0) 6025 goto out_unlock; 6026 ret = 0; 6027 out_unlock: 6028 if (ret) 6029 ret = VM_FAULT_SIGBUS; 6030 up_read(&inode->i_alloc_sem); 6031 return ret; 6032 } 6033