| 1 | |
| 2 | |
| 3 | * linux/fs/ext4/indirect.c
|
| 4 | *
|
| 5 | * from
|
| 6 | *
|
| 7 | * linux/fs/ext4/inode.c
|
| 8 | *
|
| 9 | * Copyright (C) 1992, 1993, 1994, 1995
|
| 10 | * Remy Card ([email protected])
|
| 11 | * Laboratoire MASI - Institut Blaise Pascal
|
| 12 | * Universite Pierre et Marie Curie (Paris VI)
|
| 13 | *
|
| 14 | * from
|
| 15 | *
|
| 16 | * linux/fs/minix/inode.c
|
| 17 | *
|
| 18 | * Copyright (C) 1991, 1992 Linus Torvalds
|
| 19 | *
|
| 20 | * Goal-directed block allocation by Stephen Tweedie
|
| 21 | * ([email protected]), 1993, 1998
|
| 22 |
|
| 23 |
|
| 24 | #include "ext4_jbd2.h"
|
| 25 | #include "truncate.h"
|
| 26 | #include <linux/dax.h>
|
| 27 | #include <linux/uio.h>
|
| 28 |
|
| 29 | #include <trace/events/ext4.h>
|
| 30 |
|
| 31 | typedef struct {
|
| 32 | __le32 *p;
|
| 33 | __le32 key;
|
| 34 | struct buffer_head *bh;
|
| 35 | } Indirect;
|
| 36 |
|
| 37 | static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
|
| 38 | {
|
| 39 | p->key = *(p->p = v);
|
| 40 | p->bh = bh;
|
| 41 | }
|
| 42 |
|
| 43 | |
| 44 | * ext4_block_to_path - parse the block number into array of offsets
|
| 45 | * @inode: inode in question (we are only interested in its superblock)
|
| 46 | * @i_block: block number to be parsed
|
| 47 | * @offsets: array to store the offsets in
|
| 48 | * @boundary: set this non-zero if the referred-to block is likely to be
|
| 49 | * followed (on disk) by an indirect block.
|
| 50 | *
|
| 51 | * To store the locations of file's data ext4 uses a data structure common
|
| 52 | * for UNIX filesystems - tree of pointers anchored in the inode, with
|
| 53 | * data blocks at leaves and indirect blocks in intermediate nodes.
|
| 54 | * This function translates the block number into path in that tree -
|
| 55 | * return value is the path length and @offsets[n] is the offset of
|
| 56 | * pointer to (n+1)th node in the nth one. If @block is out of range
|
| 57 | * (negative or too large) warning is printed and zero returned.
|
| 58 | *
|
| 59 | * Note: function doesn't find node addresses, so no IO is needed. All
|
| 60 | * we need to know is the capacity of indirect blocks (taken from the
|
| 61 | * inode->i_sb).
|
| 62 |
|
| 63 |
|
| 64 | |
| 65 | * Portability note: the last comparison (check that we fit into triple
|
| 66 | * indirect block) is spelled differently, because otherwise on an
|
| 67 | * architecture with 32-bit longs and 8Kb pages we might get into trouble
|
| 68 | * if our filesystem had 8Kb blocks. We might use long long, but that would
|
| 69 | * kill us on x86. Oh, well, at least the sign propagation does not matter -
|
| 70 | * i_block would have to be negative in the very beginning, so we would not
|
| 71 | * get there at all.
|
| 72 |
|
| 73 |
|
| 74 | static int ext4_block_to_path(struct inode *inode,
|
| 75 | ext4_lblk_t i_block,
|
| 76 | ext4_lblk_t offsets[4], int *boundary)
|
| 77 | {
|
| 78 | int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
| 79 | int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
|
| 80 | const long direct_blocks = EXT4_NDIR_BLOCKS,
|
| 81 | indirect_blocks = ptrs,
|
| 82 | double_blocks = (1 << (ptrs_bits * 2));
|
| 83 | int n = 0;
|
| 84 | int final = 0;
|
| 85 |
|
| 86 | if (i_block < direct_blocks) {
|
| 87 | offsets[n++] = i_block;
|
| 88 | final = direct_blocks;
|
| 89 | } else if ((i_block -= direct_blocks) < indirect_blocks) {
|
| 90 | offsets[n++] = EXT4_IND_BLOCK;
|
| 91 | offsets[n++] = i_block;
|
| 92 | final = ptrs;
|
| 93 | } else if ((i_block -= indirect_blocks) < double_blocks) {
|
| 94 | offsets[n++] = EXT4_DIND_BLOCK;
|
| 95 | offsets[n++] = i_block >> ptrs_bits;
|
| 96 | offsets[n++] = i_block & (ptrs - 1);
|
| 97 | final = ptrs;
|
| 98 | } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
|
| 99 | offsets[n++] = EXT4_TIND_BLOCK;
|
| 100 | offsets[n++] = i_block >> (ptrs_bits * 2);
|
| 101 | offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
|
| 102 | offsets[n++] = i_block & (ptrs - 1);
|
| 103 | final = ptrs;
|
| 104 | } else {
|
| 105 | ext4_warning(inode->i_sb, "block %lu > max in inode %llu",
|
| 106 | i_block + direct_blocks +
|
| 107 | indirect_blocks + double_blocks, inode->i_ino);
|
| 108 | }
|
| 109 | if (boundary)
|
| 110 | *boundary = final - 1 - (i_block & (ptrs - 1));
|
| 111 | return n;
|
| 112 | }
|
| 113 |
|
| 114 | |
| 115 | * ext4_get_branch - read the chain of indirect blocks leading to data
|
| 116 | * @inode: inode in question
|
| 117 | * @depth: depth of the chain (1 - direct pointer, etc.)
|
| 118 | * @offsets: offsets of pointers in inode/indirect blocks
|
| 119 | * @chain: place to store the result
|
| 120 | * @err: here we store the error value
|
| 121 | *
|
| 122 | * Function fills the array of triples <key, p, bh> and returns %NULL
|
| 123 | * if everything went OK or the pointer to the last filled triple
|
| 124 | * (incomplete one) otherwise. Upon the return chain[i].key contains
|
| 125 | * the number of (i+1)-th block in the chain (as it is stored in memory,
|
| 126 | * i.e. little-endian 32-bit), chain[i].p contains the address of that
|
| 127 | * number (it points into struct inode for i==0 and into the bh->b_data
|
| 128 | * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
|
| 129 | * block for i>0 and NULL for i==0. In other words, it holds the block
|
| 130 | * numbers of the chain, addresses they were taken from (and where we can
|
| 131 | * verify that chain did not change) and buffer_heads hosting these
|
| 132 | * numbers.
|
| 133 | *
|
| 134 | * Function stops when it stumbles upon zero pointer (absent block)
|
| 135 | * (pointer to last triple returned, *@err == 0)
|
| 136 | * or when it gets an IO error reading an indirect block
|
| 137 | * (ditto, *@err == -EIO)
|
| 138 | * or when it reads all @depth-1 indirect blocks successfully and finds
|
| 139 | * the whole chain, all way to the data (returns %NULL, *err == 0).
|
| 140 | *
|
| 141 | * Need to be called with
|
| 142 | * down_read(&EXT4_I(inode)->i_data_sem)
|
| 143 |
|
| 144 | static Indirect *ext4_get_branch(struct inode *inode, int depth,
|
| 145 | ext4_lblk_t *offsets,
|
| 146 | Indirect chain[4], int *err)
|
| 147 | {
|
| 148 | struct super_block *sb = inode->i_sb;
|
| 149 | Indirect *p = chain;
|
| 150 | struct buffer_head *bh;
|
| 151 | unsigned int key;
|
| 152 | int ret = -EIO;
|
| 153 |
|
| 154 | *err = 0;
|
| 155 |
|
| 156 | add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
|
| 157 | if (!p->key)
|
| 158 | goto no_block;
|
| 159 | while (--depth) {
|
| 160 | key = le32_to_cpu(p->key);
|
| 161 | if (key > ext4_blocks_count(EXT4_SB(sb)->s_es)) {
|
| 162 |
|
| 163 | ret = -EFSCORRUPTED;
|
| 164 | goto failure;
|
| 165 | }
|
| 166 | bh = sb_getblk(sb, key);
|
| 167 | if (unlikely(!bh)) {
|
| 168 | ret = -ENOMEM;
|
| 169 | goto failure;
|
| 170 | }
|
| 171 |
|
| 172 | if (!bh_uptodate_or_lock(bh)) {
|
| 173 | if (ext4_read_bh(bh, 0, NULL, false) < 0) {
|
| 174 | put_bh(bh);
|
| 175 | goto failure;
|
| 176 | }
|
| 177 |
|
| 178 | if (ext4_check_indirect_blockref(inode, bh)) {
|
| 179 | put_bh(bh);
|
| 180 | goto failure;
|
| 181 | }
|
| 182 | }
|
| 183 |
|
| 184 | add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
|
| 185 |
|
| 186 | if (!p->key)
|
| 187 | goto no_block;
|
| 188 | }
|
| 189 | return NULL;
|
| 190 |
|
| 191 | failure:
|
| 192 | *err = ret;
|
| 193 | no_block:
|
| 194 | return p;
|
| 195 | }
|
| 196 |
|
| 197 | |
| 198 | * ext4_find_near - find a place for allocation with sufficient locality
|
| 199 | * @inode: owner
|
| 200 | * @ind: descriptor of indirect block.
|
| 201 | *
|
| 202 | * This function returns the preferred place for block allocation.
|
| 203 | * It is used when heuristic for sequential allocation fails.
|
| 204 | * Rules are:
|
| 205 | * + if there is a block to the left of our position - allocate near it.
|
| 206 | * + if pointer will live in indirect block - allocate near that block.
|
| 207 | * + if pointer will live in inode - allocate in the same
|
| 208 | * cylinder group.
|
| 209 | *
|
| 210 | * In the latter case we colour the starting block by the callers PID to
|
| 211 | * prevent it from clashing with concurrent allocations for a different inode
|
| 212 | * in the same block group. The PID is used here so that functionally related
|
| 213 | * files will be close-by on-disk.
|
| 214 | *
|
| 215 | * Caller must make sure that @ind is valid and will stay that way.
|
| 216 |
|
| 217 | static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
|
| 218 | {
|
| 219 | struct ext4_inode_info *ei = EXT4_I(inode);
|
| 220 | __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
|
| 221 | __le32 *p;
|
| 222 |
|
| 223 |
|
| 224 | for (p = ind->p - 1; p >= start; p--) {
|
| 225 | if (*p)
|
| 226 | return le32_to_cpu(*p);
|
| 227 | }
|
| 228 |
|
| 229 |
|
| 230 | if (ind->bh)
|
| 231 | return ind->bh->b_blocknr;
|
| 232 |
|
| 233 | |
| 234 | * It is going to be referred to from the inode itself? OK, just put it
|
| 235 | * into the same cylinder group then.
|
| 236 |
|
| 237 | return ext4_inode_to_goal_block(inode);
|
| 238 | }
|
| 239 |
|
| 240 | |
| 241 | * ext4_find_goal - find a preferred place for allocation.
|
| 242 | * @inode: owner
|
| 243 | * @block: block we want
|
| 244 | * @partial: pointer to the last triple within a chain
|
| 245 | *
|
| 246 | * Normally this function find the preferred place for block allocation,
|
| 247 | * returns it.
|
| 248 | * Because this is only used for non-extent files, we limit the block nr
|
| 249 | * to 32 bits.
|
| 250 |
|
| 251 | static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
|
| 252 | Indirect *partial)
|
| 253 | {
|
| 254 | ext4_fsblk_t goal;
|
| 255 |
|
| 256 | |
| 257 | * XXX need to get goal block from mballoc's data structures
|
| 258 |
|
| 259 |
|
| 260 | goal = ext4_find_near(inode, partial);
|
| 261 | goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
|
| 262 | return goal;
|
| 263 | }
|
| 264 |
|
| 265 | |
| 266 | * ext4_blks_to_allocate - Look up the block map and count the number
|
| 267 | * of direct blocks need to be allocated for the given branch.
|
| 268 | *
|
| 269 | * @branch: chain of indirect blocks
|
| 270 | * @k: number of blocks need for indirect blocks
|
| 271 | * @blks: number of data blocks to be mapped.
|
| 272 | * @blocks_to_boundary: the offset in the indirect block
|
| 273 | *
|
| 274 | * return the total number of blocks to be allocate, including the
|
| 275 | * direct and indirect blocks.
|
| 276 |
|
| 277 | static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
|
| 278 | int blocks_to_boundary)
|
| 279 | {
|
| 280 | unsigned int count = 0;
|
| 281 |
|
| 282 | |
| 283 | * Simple case, [t,d]Indirect block(s) has not allocated yet
|
| 284 | * then it's clear blocks on that path have not allocated
|
| 285 |
|
| 286 | if (k > 0) {
|
| 287 |
|
| 288 | if (blks < blocks_to_boundary + 1)
|
| 289 | count += blks;
|
| 290 | else
|
| 291 | count += blocks_to_boundary + 1;
|
| 292 | return count;
|
| 293 | }
|
| 294 |
|
| 295 | count++;
|
| 296 | while (count < blks && count <= blocks_to_boundary &&
|
| 297 | le32_to_cpu(*(branch[0].p + count)) == 0) {
|
| 298 | count++;
|
| 299 | }
|
| 300 | return count;
|
| 301 | }
|
| 302 |
|
| 303 | |
| 304 | * ext4_alloc_branch() - allocate and set up a chain of blocks
|
| 305 | * @handle: handle for this transaction
|
| 306 | * @ar: structure describing the allocation request
|
| 307 | * @indirect_blks: number of allocated indirect blocks
|
| 308 | * @offsets: offsets (in the blocks) to store the pointers to next.
|
| 309 | * @branch: place to store the chain in.
|
| 310 | *
|
| 311 | * This function allocates blocks, zeroes out all but the last one,
|
| 312 | * links them into chain and (if we are synchronous) writes them to disk.
|
| 313 | * In other words, it prepares a branch that can be spliced onto the
|
| 314 | * inode. It stores the information about that chain in the branch[], in
|
| 315 | * the same format as ext4_get_branch() would do. We are calling it after
|
| 316 | * we had read the existing part of chain and partial points to the last
|
| 317 | * triple of that (one with zero ->key). Upon the exit we have the same
|
| 318 | * picture as after the successful ext4_get_block(), except that in one
|
| 319 | * place chain is disconnected - *branch->p is still zero (we did not
|
| 320 | * set the last link), but branch->key contains the number that should
|
| 321 | * be placed into *branch->p to fill that gap.
|
| 322 | *
|
| 323 | * If allocation fails we free all blocks we've allocated (and forget
|
| 324 | * their buffer_heads) and return the error value the from failed
|
| 325 | * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
|
| 326 | * as described above and return 0.
|
| 327 |
|
| 328 | static int ext4_alloc_branch(handle_t *handle,
|
| 329 | struct ext4_allocation_request *ar,
|
| 330 | int indirect_blks, ext4_lblk_t *offsets,
|
| 331 | Indirect *branch)
|
| 332 | {
|
| 333 | struct buffer_head * bh;
|
| 334 | ext4_fsblk_t b, new_blocks[4];
|
| 335 | __le32 *p;
|
| 336 | int i, j, err, len = 1;
|
| 337 |
|
| 338 | for (i = 0; i <= indirect_blks; i++) {
|
| 339 | if (i == indirect_blks) {
|
| 340 | new_blocks[i] = ext4_mb_new_blocks(handle, ar, &err);
|
| 341 | } else {
|
| 342 | ar->goal = new_blocks[i] = ext4_new_meta_blocks(handle,
|
| 343 | ar->inode, ar->goal,
|
| 344 | ar->flags & EXT4_MB_DELALLOC_RESERVED,
|
| 345 | NULL, &err);
|
| 346 |
|
| 347 | branch[i+1].bh = NULL;
|
| 348 | }
|
| 349 | if (err) {
|
| 350 | i--;
|
| 351 | goto failed;
|
| 352 | }
|
| 353 | branch[i].key = cpu_to_le32(new_blocks[i]);
|
| 354 | if (i == 0)
|
| 355 | continue;
|
| 356 |
|
| 357 | bh = branch[i].bh = sb_getblk(ar->inode->i_sb, new_blocks[i-1]);
|
| 358 | if (unlikely(!bh)) {
|
| 359 | err = -ENOMEM;
|
| 360 | goto failed;
|
| 361 | }
|
| 362 | lock_buffer(bh);
|
| 363 | BUFFER_TRACE(bh, "call get_create_access");
|
| 364 | err = ext4_journal_get_create_access(handle, ar->inode->i_sb,
|
| 365 | bh, EXT4_JTR_NONE);
|
| 366 | if (err) {
|
| 367 | unlock_buffer(bh);
|
| 368 | goto failed;
|
| 369 | }
|
| 370 |
|
| 371 | memset(bh->b_data, 0, bh->b_size);
|
| 372 | p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
|
| 373 | b = new_blocks[i];
|
| 374 |
|
| 375 | if (i == indirect_blks)
|
| 376 | len = ar->len;
|
| 377 | for (j = 0; j < len; j++)
|
| 378 | *p++ = cpu_to_le32(b++);
|
| 379 |
|
| 380 | BUFFER_TRACE(bh, "marking uptodate");
|
| 381 | set_buffer_uptodate(bh);
|
| 382 | unlock_buffer(bh);
|
| 383 |
|
| 384 | BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
| 385 | err = ext4_handle_dirty_metadata(handle, ar->inode, bh);
|
| 386 | if (err)
|
| 387 | goto failed;
|
| 388 | }
|
| 389 | return 0;
|
| 390 | failed:
|
| 391 | if (i == indirect_blks) {
|
| 392 |
|
| 393 | ext4_free_blocks(handle, ar->inode, NULL, new_blocks[i],
|
| 394 | ar->len, 0);
|
| 395 | i--;
|
| 396 | }
|
| 397 | for (; i >= 0; i--) {
|
| 398 | |
| 399 | * We want to ext4_forget() only freshly allocated indirect
|
| 400 | * blocks. Buffer for new_blocks[i] is at branch[i+1].bh
|
| 401 | * (buffer at branch[0].bh is indirect block / inode already
|
| 402 | * existing before ext4_alloc_branch() was called). Also
|
| 403 | * because blocks are freshly allocated, we don't need to
|
| 404 | * revoke them which is why we don't set
|
| 405 | * EXT4_FREE_BLOCKS_METADATA.
|
| 406 |
|
| 407 | ext4_free_blocks(handle, ar->inode, branch[i+1].bh,
|
| 408 | new_blocks[i], 1,
|
| 409 | branch[i+1].bh ? EXT4_FREE_BLOCKS_FORGET : 0);
|
| 410 | }
|
| 411 | return err;
|
| 412 | }
|
| 413 |
|
| 414 | |
| 415 | * ext4_splice_branch() - splice the allocated branch onto inode.
|
| 416 | * @handle: handle for this transaction
|
| 417 | * @ar: structure describing the allocation request
|
| 418 | * @where: location of missing link
|
| 419 | * @num: number of indirect blocks we are adding
|
| 420 | *
|
| 421 | * This function fills the missing link and does all housekeeping needed in
|
| 422 | * inode (->i_blocks, etc.). In case of success we end up with the full
|
| 423 | * chain to new block and return 0.
|
| 424 |
|
| 425 | static int ext4_splice_branch(handle_t *handle,
|
| 426 | struct ext4_allocation_request *ar,
|
| 427 | Indirect *where, int num)
|
| 428 | {
|
| 429 | int i;
|
| 430 | int err = 0;
|
| 431 | ext4_fsblk_t current_block;
|
| 432 |
|
| 433 | |
| 434 | * If we're splicing into a [td]indirect block (as opposed to the
|
| 435 | * inode) then we need to get write access to the [td]indirect block
|
| 436 | * before the splice.
|
| 437 |
|
| 438 | if (where->bh) {
|
| 439 | BUFFER_TRACE(where->bh, "get_write_access");
|
| 440 | err = ext4_journal_get_write_access(handle, ar->inode->i_sb,
|
| 441 | where->bh, EXT4_JTR_NONE);
|
| 442 | if (err)
|
| 443 | goto err_out;
|
| 444 | }
|
| 445 |
|
| 446 |
|
| 447 | *where->p = where->key;
|
| 448 |
|
| 449 | |
| 450 | * Update the host buffer_head or inode to point to more just allocated
|
| 451 | * direct blocks blocks
|
| 452 |
|
| 453 | if (num == 0 && ar->len > 1) {
|
| 454 | current_block = le32_to_cpu(where->key) + 1;
|
| 455 | for (i = 1; i < ar->len; i++)
|
| 456 | *(where->p + i) = cpu_to_le32(current_block++);
|
| 457 | }
|
| 458 |
|
| 459 |
|
| 460 |
|
| 461 | if (where->bh) {
|
| 462 | |
| 463 | * If we spliced it onto an indirect block, we haven't
|
| 464 | * altered the inode. Note however that if it is being spliced
|
| 465 | * onto an indirect block at the very end of the file (the
|
| 466 | * file is growing) then we *will* alter the inode to reflect
|
| 467 | * the new i_size. But that is not done here - it is done in
|
| 468 | * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
|
| 469 |
|
| 470 | ext4_debug("splicing indirect only\n");
|
| 471 | BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
|
| 472 | err = ext4_handle_dirty_metadata(handle, ar->inode, where->bh);
|
| 473 | if (err)
|
| 474 | goto err_out;
|
| 475 | } else {
|
| 476 | |
| 477 | * OK, we spliced it into the inode itself on a direct block.
|
| 478 |
|
| 479 | err = ext4_mark_inode_dirty(handle, ar->inode);
|
| 480 | if (unlikely(err))
|
| 481 | goto err_out;
|
| 482 | ext4_debug("splicing direct\n");
|
| 483 | }
|
| 484 | return err;
|
| 485 |
|
| 486 | err_out:
|
| 487 | for (i = 1; i <= num; i++) {
|
| 488 | |
| 489 | * branch[i].bh is newly allocated, so there is no
|
| 490 | * need to revoke the block, which is why we don't
|
| 491 | * need to set EXT4_FREE_BLOCKS_METADATA.
|
| 492 |
|
| 493 | ext4_free_blocks(handle, ar->inode, where[i].bh, 0, 1,
|
| 494 | EXT4_FREE_BLOCKS_FORGET);
|
| 495 | }
|
| 496 | ext4_free_blocks(handle, ar->inode, NULL, le32_to_cpu(where[num].key),
|
| 497 | ar->len, 0);
|
| 498 |
|
| 499 | return err;
|
| 500 | }
|
| 501 |
|
| 502 | |
| 503 | * The ext4_ind_map_blocks() function handles non-extents inodes
|
| 504 | * (i.e., using the traditional indirect/double-indirect i_blocks
|
| 505 | * scheme) for ext4_map_blocks().
|
| 506 | *
|
| 507 | * Allocation strategy is simple: if we have to allocate something, we will
|
| 508 | * have to go the whole way to leaf. So let's do it before attaching anything
|
| 509 | * to tree, set linkage between the newborn blocks, write them if sync is
|
| 510 | * required, recheck the path, free and repeat if check fails, otherwise
|
| 511 | * set the last missing link (that will protect us from any truncate-generated
|
| 512 | * removals - all blocks on the path are immune now) and possibly force the
|
| 513 | * write on the parent block.
|
| 514 | * That has a nice additional property: no special recovery from the failed
|
| 515 | * allocations is needed - we simply release blocks and do not touch anything
|
| 516 | * reachable from inode.
|
| 517 | *
|
| 518 | * `handle' can be NULL if create == 0.
|
| 519 | *
|
| 520 | * return > 0, # of blocks mapped or allocated.
|
| 521 | * return = 0, if plain lookup failed.
|
| 522 | * return < 0, error case.
|
| 523 | *
|
| 524 | * The ext4_ind_get_blocks() function should be called with
|
| 525 | * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
|
| 526 | * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
|
| 527 | * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
|
| 528 | * blocks.
|
| 529 |
|
| 530 | int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
|
| 531 | struct ext4_map_blocks *map,
|
| 532 | int flags)
|
| 533 | {
|
| 534 | struct ext4_allocation_request ar;
|
| 535 | int err = -EIO;
|
| 536 | ext4_lblk_t offsets[4];
|
| 537 | Indirect chain[4];
|
| 538 | Indirect *partial;
|
| 539 | int indirect_blks;
|
| 540 | int blocks_to_boundary = 0;
|
| 541 | int depth;
|
| 542 | u64 count = 0;
|
| 543 | ext4_fsblk_t first_block = 0;
|
| 544 |
|
| 545 | trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
|
| 546 | ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
|
| 547 | ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
|
| 548 | depth = ext4_block_to_path(inode, map->m_lblk, offsets,
|
| 549 | &blocks_to_boundary);
|
| 550 |
|
| 551 | if (depth == 0)
|
| 552 | goto out;
|
| 553 |
|
| 554 | partial = ext4_get_branch(inode, depth, offsets, chain, &err);
|
| 555 |
|
| 556 |
|
| 557 | if (!partial) {
|
| 558 | first_block = le32_to_cpu(chain[depth - 1].key);
|
| 559 | count++;
|
| 560 |
|
| 561 | while (count < map->m_len && count <= blocks_to_boundary) {
|
| 562 | ext4_fsblk_t blk;
|
| 563 |
|
| 564 | blk = le32_to_cpu(*(chain[depth-1].p + count));
|
| 565 |
|
| 566 | if (blk == first_block + count)
|
| 567 | count++;
|
| 568 | else
|
| 569 | break;
|
| 570 | }
|
| 571 | goto got_it;
|
| 572 | }
|
| 573 |
|
| 574 |
|
| 575 | if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
|
| 576 | unsigned epb = inode->i_sb->s_blocksize / sizeof(u32);
|
| 577 | int i;
|
| 578 |
|
| 579 | |
| 580 | * Count number blocks in a subtree under 'partial'. At each
|
| 581 | * level we count number of complete empty subtrees beyond
|
| 582 | * current offset and then descend into the subtree only
|
| 583 | * partially beyond current offset.
|
| 584 |
|
| 585 | count = 0;
|
| 586 | for (i = partial - chain + 1; i < depth; i++)
|
| 587 | count = count * epb + (epb - offsets[i] - 1);
|
| 588 | count++;
|
| 589 |
|
| 590 | map->m_pblk = 0;
|
| 591 | map->m_len = umin(map->m_len, count);
|
| 592 | goto cleanup;
|
| 593 | }
|
| 594 |
|
| 595 |
|
| 596 | if (err == -EIO)
|
| 597 | goto cleanup;
|
| 598 |
|
| 599 | |
| 600 | * Okay, we need to do block allocation.
|
| 601 |
|
| 602 | if (ext4_has_feature_bigalloc(inode->i_sb)) {
|
| 603 | EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
|
| 604 | "non-extent mapped inodes with bigalloc");
|
| 605 | err = -EFSCORRUPTED;
|
| 606 | goto out;
|
| 607 | }
|
| 608 |
|
| 609 |
|
| 610 | memset(&ar, 0, sizeof(ar));
|
| 611 | ar.inode = inode;
|
| 612 | ar.logical = map->m_lblk;
|
| 613 | if (S_ISREG(inode->i_mode))
|
| 614 | ar.flags = EXT4_MB_HINT_DATA;
|
| 615 | if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
|
| 616 | ar.flags |= EXT4_MB_DELALLOC_RESERVED;
|
| 617 | if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
|
| 618 | ar.flags |= EXT4_MB_USE_RESERVED;
|
| 619 |
|
| 620 | ar.goal = ext4_find_goal(inode, map->m_lblk, partial);
|
| 621 |
|
| 622 |
|
| 623 | indirect_blks = (chain + depth) - partial - 1;
|
| 624 |
|
| 625 | |
| 626 | * Next look up the indirect map to count the totoal number of
|
| 627 | * direct blocks to allocate for this branch.
|
| 628 |
|
| 629 | ar.len = ext4_blks_to_allocate(partial, indirect_blks,
|
| 630 | map->m_len, blocks_to_boundary);
|
| 631 |
|
| 632 | |
| 633 | * Block out ext4_truncate while we alter the tree
|
| 634 |
|
| 635 | err = ext4_alloc_branch(handle, &ar, indirect_blks,
|
| 636 | offsets + (partial - chain), partial);
|
| 637 |
|
| 638 | |
| 639 | * The ext4_splice_branch call will free and forget any buffers
|
| 640 | * on the new chain if there is a failure, but that risks using
|
| 641 | * up transaction credits, especially for bitmaps where the
|
| 642 | * credits cannot be returned. Can we handle this somehow? We
|
| 643 | * may need to return -EAGAIN upwards in the worst case. --sct
|
| 644 |
|
| 645 | if (!err)
|
| 646 | err = ext4_splice_branch(handle, &ar, partial, indirect_blks);
|
| 647 | if (err)
|
| 648 | goto cleanup;
|
| 649 |
|
| 650 | map->m_flags |= EXT4_MAP_NEW;
|
| 651 |
|
| 652 | ext4_update_inode_fsync_trans(handle, inode, 1);
|
| 653 | count = ar.len;
|
| 654 |
|
| 655 | got_it:
|
| 656 | map->m_flags |= EXT4_MAP_MAPPED;
|
| 657 | map->m_pblk = le32_to_cpu(chain[depth-1].key);
|
| 658 | map->m_len = count;
|
| 659 | if (count > blocks_to_boundary)
|
| 660 | map->m_flags |= EXT4_MAP_BOUNDARY;
|
| 661 | err = count;
|
| 662 |
|
| 663 | partial = chain + depth - 1;
|
| 664 | cleanup:
|
| 665 | while (partial > chain) {
|
| 666 | BUFFER_TRACE(partial->bh, "call brelse");
|
| 667 | brelse(partial->bh);
|
| 668 | partial--;
|
| 669 | }
|
| 670 | out:
|
| 671 | trace_ext4_ind_map_blocks_exit(inode, flags, map, err);
|
| 672 | return err;
|
| 673 | }
|
| 674 |
|
| 675 | |
| 676 | * Calculate number of indirect blocks touched by mapping @nrblocks logically
|
| 677 | * contiguous blocks
|
| 678 |
|
| 679 | int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
|
| 680 | {
|
| 681 | |
| 682 | * With N contiguous data blocks, we need at most
|
| 683 | * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
|
| 684 | * 2 dindirect blocks, and 1 tindirect block
|
| 685 |
|
| 686 | return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
|
| 687 | }
|
| 688 |
|
| 689 | static int ext4_ind_trunc_restart_fn(handle_t *handle, struct inode *inode,
|
| 690 | struct buffer_head *bh, int *dropped)
|
| 691 | {
|
| 692 | int err;
|
| 693 |
|
| 694 | if (bh) {
|
| 695 | BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
| 696 | err = ext4_handle_dirty_metadata(handle, inode, bh);
|
| 697 | if (unlikely(err))
|
| 698 | return err;
|
| 699 | }
|
| 700 | err = ext4_mark_inode_dirty(handle, inode);
|
| 701 | if (unlikely(err))
|
| 702 | return err;
|
| 703 | |
| 704 | * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
|
| 705 | * moment, get_block can be called only for blocks inside i_size since
|
| 706 | * page cache has been already dropped and writes are blocked by
|
| 707 | * i_rwsem. So we can safely drop the i_data_sem here.
|
| 708 |
|
| 709 | BUG_ON(EXT4_JOURNAL(inode) == NULL);
|
| 710 | ext4_discard_preallocations(inode);
|
| 711 | up_write(&EXT4_I(inode)->i_data_sem);
|
| 712 | *dropped = 1;
|
| 713 | return 0;
|
| 714 | }
|
| 715 |
|
| 716 | |
| 717 | * Truncate transactions can be complex and absolutely huge. So we need to
|
| 718 | * be able to restart the transaction at a convenient checkpoint to make
|
| 719 | * sure we don't overflow the journal.
|
| 720 | *
|
| 721 | * Try to extend this transaction for the purposes of truncation. If
|
| 722 | * extend fails, we restart transaction.
|
| 723 |
|
| 724 | static int ext4_ind_truncate_ensure_credits(handle_t *handle,
|
| 725 | struct inode *inode,
|
| 726 | struct buffer_head *bh,
|
| 727 | int revoke_creds)
|
| 728 | {
|
| 729 | int ret;
|
| 730 | int dropped = 0;
|
| 731 |
|
| 732 | ret = ext4_journal_ensure_credits_fn(handle, EXT4_RESERVE_TRANS_BLOCKS,
|
| 733 | ext4_blocks_for_truncate(inode), revoke_creds,
|
| 734 | ext4_ind_trunc_restart_fn(handle, inode, bh, &dropped));
|
| 735 | if (dropped)
|
| 736 | down_write(&EXT4_I(inode)->i_data_sem);
|
| 737 | if (ret <= 0)
|
| 738 | return ret;
|
| 739 | if (bh) {
|
| 740 | BUFFER_TRACE(bh, "retaking write access");
|
| 741 | ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
|
| 742 | EXT4_JTR_NONE);
|
| 743 | if (unlikely(ret))
|
| 744 | return ret;
|
| 745 | }
|
| 746 | return 0;
|
| 747 | }
|
| 748 |
|
| 749 | |
| 750 | * Probably it should be a library function... search for first non-zero word
|
| 751 | * or memcmp with zero_page, whatever is better for particular architecture.
|
| 752 | * Linus?
|
| 753 |
|
| 754 | static inline int all_zeroes(__le32 *p, __le32 *q)
|
| 755 | {
|
| 756 | while (p < q)
|
| 757 | if (*p++)
|
| 758 | return 0;
|
| 759 | return 1;
|
| 760 | }
|
| 761 |
|
| 762 | |
| 763 | * ext4_find_shared - find the indirect blocks for partial truncation.
|
| 764 | * @inode: inode in question
|
| 765 | * @depth: depth of the affected branch
|
| 766 | * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
|
| 767 | * @chain: place to store the pointers to partial indirect blocks
|
| 768 | * @top: place to the (detached) top of branch
|
| 769 | *
|
| 770 | * This is a helper function used by ext4_truncate().
|
| 771 | *
|
| 772 | * When we do truncate() we may have to clean the ends of several
|
| 773 | * indirect blocks but leave the blocks themselves alive. Block is
|
| 774 | * partially truncated if some data below the new i_size is referred
|
| 775 | * from it (and it is on the path to the first completely truncated
|
| 776 | * data block, indeed). We have to free the top of that path along
|
| 777 | * with everything to the right of the path. Since no allocation
|
| 778 | * past the truncation point is possible until ext4_truncate()
|
| 779 | * finishes, we may safely do the latter, but top of branch may
|
| 780 | * require special attention - pageout below the truncation point
|
| 781 | * might try to populate it.
|
| 782 | *
|
| 783 | * We atomically detach the top of branch from the tree, store the
|
| 784 | * block number of its root in *@top, pointers to buffer_heads of
|
| 785 | * partially truncated blocks - in @chain[].bh and pointers to
|
| 786 | * their last elements that should not be removed - in
|
| 787 | * @chain[].p. Return value is the pointer to last filled element
|
| 788 | * of @chain.
|
| 789 | *
|
| 790 | * The work left to caller to do the actual freeing of subtrees:
|
| 791 | * a) free the subtree starting from *@top
|
| 792 | * b) free the subtrees whose roots are stored in
|
| 793 | * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
|
| 794 | * c) free the subtrees growing from the inode past the @chain[0].
|
| 795 | * (no partially truncated stuff there).
|
| 796 |
|
| 797 | static Indirect *ext4_find_shared(struct inode *inode, int depth,
|
| 798 | ext4_lblk_t offsets[4], Indirect chain[4],
|
| 799 | __le32 *top)
|
| 800 | {
|
| 801 | Indirect *partial, *p;
|
| 802 | int k, err;
|
| 803 |
|
| 804 | *top = 0;
|
| 805 |
|
| 806 | for (k = depth; k > 1 && !offsets[k-1]; k--)
|
| 807 | ;
|
| 808 | partial = ext4_get_branch(inode, k, offsets, chain, &err);
|
| 809 |
|
| 810 | if (!partial)
|
| 811 | partial = chain + k-1;
|
| 812 | |
| 813 | * If the branch acquired continuation since we've looked at it -
|
| 814 | * fine, it should all survive and (new) top doesn't belong to us.
|
| 815 |
|
| 816 | if (!partial->key && *partial->p)
|
| 817 |
|
| 818 | goto no_top;
|
| 819 | for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
|
| 820 | ;
|
| 821 | |
| 822 | * OK, we've found the last block that must survive. The rest of our
|
| 823 | * branch should be detached before unlocking. However, if that rest
|
| 824 | * of branch is all ours and does not grow immediately from the inode
|
| 825 | * it's easier to cheat and just decrement partial->p.
|
| 826 |
|
| 827 | if (p == chain + k - 1 && p > chain) {
|
| 828 | p->p--;
|
| 829 | } else {
|
| 830 | *top = *p->p;
|
| 831 |
|
| 832 | #if 0 |
| 833 | *p->p = 0;
|
| 834 | #endif
|
| 835 | }
|
| 836 |
|
| 837 |
|
| 838 | while (partial > p) {
|
| 839 | brelse(partial->bh);
|
| 840 | partial--;
|
| 841 | }
|
| 842 | no_top:
|
| 843 | return partial;
|
| 844 | }
|
| 845 |
|
| 846 | |
| 847 | * Zero a number of block pointers in either an inode or an indirect block.
|
| 848 | * If we restart the transaction we must again get write access to the
|
| 849 | * indirect block for further modification.
|
| 850 | *
|
| 851 | * We release `count' blocks on disk, but (last - first) may be greater
|
| 852 | * than `count' because there can be holes in there.
|
| 853 | *
|
| 854 | * Return 0 on success, 1 on invalid block range
|
| 855 | * and < 0 on fatal error.
|
| 856 |
|
| 857 | static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
|
| 858 | struct buffer_head *bh,
|
| 859 | ext4_fsblk_t block_to_free,
|
| 860 | unsigned long count, __le32 *first,
|
| 861 | __le32 *last)
|
| 862 | {
|
| 863 | __le32 *p;
|
| 864 | int flags = EXT4_FREE_BLOCKS_VALIDATED;
|
| 865 | int err;
|
| 866 |
|
| 867 | if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
|
| 868 | ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
|
| 869 | flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
|
| 870 | else if (ext4_should_journal_data(inode))
|
| 871 | flags |= EXT4_FREE_BLOCKS_FORGET;
|
| 872 |
|
| 873 | if (!ext4_inode_block_valid(inode, block_to_free, count)) {
|
| 874 | EXT4_ERROR_INODE(inode, "attempt to clear invalid "
|
| 875 | "blocks %llu len %lu",
|
| 876 | (unsigned long long) block_to_free, count);
|
| 877 | return 1;
|
| 878 | }
|
| 879 |
|
| 880 | err = ext4_ind_truncate_ensure_credits(handle, inode, bh,
|
| 881 | ext4_free_data_revoke_credits(inode, count));
|
| 882 | if (err < 0)
|
| 883 | goto out_err;
|
| 884 |
|
| 885 | for (p = first; p < last; p++)
|
| 886 | *p = 0;
|
| 887 |
|
| 888 | ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
|
| 889 | return 0;
|
| 890 | out_err:
|
| 891 | ext4_std_error(inode->i_sb, err);
|
| 892 | return err;
|
| 893 | }
|
| 894 |
|
| 895 | |
| 896 | * ext4_free_data - free a list of data blocks
|
| 897 | * @handle: handle for this transaction
|
| 898 | * @inode: inode we are dealing with
|
| 899 | * @this_bh: indirect buffer_head which contains *@first and *@last
|
| 900 | * @first: array of block numbers
|
| 901 | * @last: points immediately past the end of array
|
| 902 | *
|
| 903 | * We are freeing all blocks referred from that array (numbers are stored as
|
| 904 | * little-endian 32-bit) and updating @inode->i_blocks appropriately.
|
| 905 | *
|
| 906 | * We accumulate contiguous runs of blocks to free. Conveniently, if these
|
| 907 | * blocks are contiguous then releasing them at one time will only affect one
|
| 908 | * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
|
| 909 | * actually use a lot of journal space.
|
| 910 | *
|
| 911 | * @this_bh will be %NULL if @first and @last point into the inode's direct
|
| 912 | * block pointers.
|
| 913 |
|
| 914 | static void ext4_free_data(handle_t *handle, struct inode *inode,
|
| 915 | struct buffer_head *this_bh,
|
| 916 | __le32 *first, __le32 *last)
|
| 917 | {
|
| 918 | ext4_fsblk_t block_to_free = 0;
|
| 919 | unsigned long count = 0;
|
| 920 | __le32 *block_to_free_p = NULL; |
| 921 | corresponding to
|
| 922 | block_to_free
|
| 923 | ext4_fsblk_t nr;
|
| 924 | __le32 *p; |
| 925 | for current block
|
| 926 | int err = 0;
|
| 927 |
|
| 928 | if (this_bh) {
|
| 929 | BUFFER_TRACE(this_bh, "get_write_access");
|
| 930 | err = ext4_journal_get_write_access(handle, inode->i_sb,
|
| 931 | this_bh, EXT4_JTR_NONE);
|
| 932 | |
| 933 | * to the blocks, we can't free them.
|
| 934 | if (err)
|
| 935 | return;
|
| 936 | }
|
| 937 |
|
| 938 | for (p = first; p < last; p++) {
|
| 939 | nr = le32_to_cpu(*p);
|
| 940 | if (nr) {
|
| 941 |
|
| 942 | if (count == 0) {
|
| 943 | block_to_free = nr;
|
| 944 | block_to_free_p = p;
|
| 945 | count = 1;
|
| 946 | } else if (nr == block_to_free + count) {
|
| 947 | count++;
|
| 948 | } else {
|
| 949 | err = ext4_clear_blocks(handle, inode, this_bh,
|
| 950 | block_to_free, count,
|
| 951 | block_to_free_p, p);
|
| 952 | if (err)
|
| 953 | break;
|
| 954 | block_to_free = nr;
|
| 955 | block_to_free_p = p;
|
| 956 | count = 1;
|
| 957 | }
|
| 958 | }
|
| 959 | }
|
| 960 |
|
| 961 | if (!err && count > 0)
|
| 962 | err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
|
| 963 | count, block_to_free_p, p);
|
| 964 | if (err < 0)
|
| 965 |
|
| 966 | return;
|
| 967 |
|
| 968 | if (this_bh) {
|
| 969 | BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
|
| 970 |
|
| 971 | |
| 972 | * The buffer head should have an attached journal head at this
|
| 973 | * point. However, if the data is corrupted and an indirect
|
| 974 | * block pointed to itself, it would have been detached when
|
| 975 | * the block was cleared. Check for this instead of OOPSing.
|
| 976 |
|
| 977 | if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
|
| 978 | ext4_handle_dirty_metadata(handle, inode, this_bh);
|
| 979 | else
|
| 980 | EXT4_ERROR_INODE(inode,
|
| 981 | "circular indirect block detected at "
|
| 982 | "block %llu",
|
| 983 | (unsigned long long) this_bh->b_blocknr);
|
| 984 | }
|
| 985 | }
|
| 986 |
|
| 987 | |
| 988 | * ext4_free_branches - free an array of branches
|
| 989 | * @handle: JBD handle for this transaction
|
| 990 | * @inode: inode we are dealing with
|
| 991 | * @parent_bh: the buffer_head which contains *@first and *@last
|
| 992 | * @first: array of block numbers
|
| 993 | * @last: pointer immediately past the end of array
|
| 994 | * @depth: depth of the branches to free
|
| 995 | *
|
| 996 | * We are freeing all blocks referred from these branches (numbers are
|
| 997 | * stored as little-endian 32-bit) and updating @inode->i_blocks
|
| 998 | * appropriately.
|
| 999 |
|
| 1000 | static void ext4_free_branches(handle_t *handle, struct inode *inode,
|
| 1001 | struct buffer_head *parent_bh,
|
| 1002 | __le32 *first, __le32 *last, int depth)
|
| 1003 | {
|
| 1004 | ext4_fsblk_t nr;
|
| 1005 | __le32 *p;
|
| 1006 |
|
| 1007 | if (ext4_handle_is_aborted(handle))
|
| 1008 | return;
|
| 1009 |
|
| 1010 | if (depth--) {
|
| 1011 | struct buffer_head *bh;
|
| 1012 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
| 1013 | p = last;
|
| 1014 | while (--p >= first) {
|
| 1015 | nr = le32_to_cpu(*p);
|
| 1016 | if (!nr)
|
| 1017 | continue;
|
| 1018 |
|
| 1019 | if (!ext4_inode_block_valid(inode, nr, 1)) {
|
| 1020 | EXT4_ERROR_INODE(inode,
|
| 1021 | "invalid indirect mapped "
|
| 1022 | "block %lu (level %d)",
|
| 1023 | (unsigned long) nr, depth);
|
| 1024 | break;
|
| 1025 | }
|
| 1026 |
|
| 1027 |
|
| 1028 | bh = ext4_sb_bread_nofail(inode->i_sb, nr);
|
| 1029 |
|
| 1030 | |
| 1031 | * A read failure? Report error and clear slot
|
| 1032 | * (should be rare).
|
| 1033 |
|
| 1034 | if (IS_ERR(bh)) {
|
| 1035 | ext4_error_inode_block(inode, nr, -PTR_ERR(bh),
|
| 1036 | "Read failure");
|
| 1037 | continue;
|
| 1038 | }
|
| 1039 |
|
| 1040 |
|
| 1041 | BUFFER_TRACE(bh, "free child branches");
|
| 1042 | ext4_free_branches(handle, inode, bh,
|
| 1043 | (__le32 *) bh->b_data,
|
| 1044 | (__le32 *) bh->b_data + addr_per_block,
|
| 1045 | depth);
|
| 1046 | brelse(bh);
|
| 1047 |
|
| 1048 | |
| 1049 | * Everything below this pointer has been
|
| 1050 | * released. Now let this top-of-subtree go.
|
| 1051 | *
|
| 1052 | * We want the freeing of this indirect block to be
|
| 1053 | * atomic in the journal with the updating of the
|
| 1054 | * bitmap block which owns it. So make some room in
|
| 1055 | * the journal.
|
| 1056 | *
|
| 1057 | * We zero the parent pointer *after* freeing its
|
| 1058 | * pointee in the bitmaps, so if extend_transaction()
|
| 1059 | * for some reason fails to put the bitmap changes and
|
| 1060 | * the release into the same transaction, recovery
|
| 1061 | * will merely complain about releasing a free block,
|
| 1062 | * rather than leaking blocks.
|
| 1063 |
|
| 1064 | if (ext4_handle_is_aborted(handle))
|
| 1065 | return;
|
| 1066 | if (ext4_ind_truncate_ensure_credits(handle, inode,
|
| 1067 | NULL,
|
| 1068 | ext4_free_metadata_revoke_credits(
|
| 1069 | inode->i_sb, 1)) < 0)
|
| 1070 | return;
|
| 1071 |
|
| 1072 | |
| 1073 | * The forget flag here is critical because if
|
| 1074 | * we are journaling (and not doing data
|
| 1075 | * journaling), we have to make sure a revoke
|
| 1076 | * record is written to prevent the journal
|
| 1077 | * replay from overwriting the (former)
|
| 1078 | * indirect block if it gets reallocated as a
|
| 1079 | * data block. This must happen in the same
|
| 1080 | * transaction where the data blocks are
|
| 1081 | * actually freed.
|
| 1082 |
|
| 1083 | ext4_free_blocks(handle, inode, NULL, nr, 1,
|
| 1084 | EXT4_FREE_BLOCKS_METADATA|
|
| 1085 | EXT4_FREE_BLOCKS_FORGET);
|
| 1086 |
|
| 1087 | if (parent_bh) {
|
| 1088 | |
| 1089 | * The block which we have just freed is
|
| 1090 | * pointed to by an indirect block: journal it
|
| 1091 |
|
| 1092 | BUFFER_TRACE(parent_bh, "get_write_access");
|
| 1093 | if (!ext4_journal_get_write_access(handle,
|
| 1094 | inode->i_sb, parent_bh,
|
| 1095 | EXT4_JTR_NONE)) {
|
| 1096 | *p = 0;
|
| 1097 | BUFFER_TRACE(parent_bh,
|
| 1098 | "call ext4_handle_dirty_metadata");
|
| 1099 | ext4_handle_dirty_metadata(handle,
|
| 1100 | inode,
|
| 1101 | parent_bh);
|
| 1102 | }
|
| 1103 | }
|
| 1104 | }
|
| 1105 | } else {
|
| 1106 |
|
| 1107 | BUFFER_TRACE(parent_bh, "free data blocks");
|
| 1108 | ext4_free_data(handle, inode, parent_bh, first, last);
|
| 1109 | }
|
| 1110 | }
|
| 1111 |
|
| 1112 | void ext4_ind_truncate(handle_t *handle, struct inode *inode)
|
| 1113 | {
|
| 1114 | struct ext4_inode_info *ei = EXT4_I(inode);
|
| 1115 | __le32 *i_data = ei->i_data;
|
| 1116 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
| 1117 | ext4_lblk_t offsets[4];
|
| 1118 | Indirect chain[4];
|
| 1119 | Indirect *partial;
|
| 1120 | __le32 nr = 0;
|
| 1121 | int n = 0;
|
| 1122 | ext4_lblk_t last_block, max_block;
|
| 1123 | unsigned blocksize = inode->i_sb->s_blocksize;
|
| 1124 |
|
| 1125 | last_block = (inode->i_size + blocksize-1)
|
| 1126 | >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
| 1127 | max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
|
| 1128 | >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
| 1129 |
|
| 1130 | if (last_block != max_block) {
|
| 1131 | n = ext4_block_to_path(inode, last_block, offsets, NULL);
|
| 1132 | if (n == 0)
|
| 1133 | return;
|
| 1134 | }
|
| 1135 |
|
| 1136 | ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
|
| 1137 |
|
| 1138 | |
| 1139 | * The orphan list entry will now protect us from any crash which
|
| 1140 | * occurs before the truncate completes, so it is now safe to propagate
|
| 1141 | * the new, shorter inode size (held for now in i_size) into the
|
| 1142 | * on-disk inode. We do this via i_disksize, which is the value which
|
| 1143 | * ext4 *really* writes onto the disk inode.
|
| 1144 |
|
| 1145 | ei->i_disksize = inode->i_size;
|
| 1146 |
|
| 1147 | if (last_block == max_block) {
|
| 1148 | |
| 1149 | * It is unnecessary to free any data blocks if last_block is
|
| 1150 | * equal to the indirect block limit.
|
| 1151 |
|
| 1152 | return;
|
| 1153 | } else if (n == 1) {
|
| 1154 | ext4_free_data(handle, inode, NULL, i_data+offsets[0],
|
| 1155 | i_data + EXT4_NDIR_BLOCKS);
|
| 1156 | goto do_indirects;
|
| 1157 | }
|
| 1158 |
|
| 1159 | partial = ext4_find_shared(inode, n, offsets, chain, &nr);
|
| 1160 |
|
| 1161 | if (nr) {
|
| 1162 | if (partial == chain) {
|
| 1163 |
|
| 1164 | ext4_free_branches(handle, inode, NULL,
|
| 1165 | &nr, &nr+1, (chain+n-1) - partial);
|
| 1166 | *partial->p = 0;
|
| 1167 | |
| 1168 | * We mark the inode dirty prior to restart,
|
| 1169 | * and prior to stop. No need for it here.
|
| 1170 |
|
| 1171 | } else {
|
| 1172 |
|
| 1173 | BUFFER_TRACE(partial->bh, "get_write_access");
|
| 1174 | ext4_free_branches(handle, inode, partial->bh,
|
| 1175 | partial->p,
|
| 1176 | partial->p+1, (chain+n-1) - partial);
|
| 1177 | }
|
| 1178 | }
|
| 1179 |
|
| 1180 | while (partial > chain) {
|
| 1181 | ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
|
| 1182 | (__le32*)partial->bh->b_data+addr_per_block,
|
| 1183 | (chain+n-1) - partial);
|
| 1184 | BUFFER_TRACE(partial->bh, "call brelse");
|
| 1185 | brelse(partial->bh);
|
| 1186 | partial--;
|
| 1187 | }
|
| 1188 | do_indirects:
|
| 1189 |
|
| 1190 | switch (offsets[0]) {
|
| 1191 | default:
|
| 1192 | nr = i_data[EXT4_IND_BLOCK];
|
| 1193 | if (nr) {
|
| 1194 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
|
| 1195 | i_data[EXT4_IND_BLOCK] = 0;
|
| 1196 | }
|
| 1197 | fallthrough;
|
| 1198 | case EXT4_IND_BLOCK:
|
| 1199 | nr = i_data[EXT4_DIND_BLOCK];
|
| 1200 | if (nr) {
|
| 1201 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
|
| 1202 | i_data[EXT4_DIND_BLOCK] = 0;
|
| 1203 | }
|
| 1204 | fallthrough;
|
| 1205 | case EXT4_DIND_BLOCK:
|
| 1206 | nr = i_data[EXT4_TIND_BLOCK];
|
| 1207 | if (nr) {
|
| 1208 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
|
| 1209 | i_data[EXT4_TIND_BLOCK] = 0;
|
| 1210 | }
|
| 1211 | fallthrough;
|
| 1212 | case EXT4_TIND_BLOCK:
|
| 1213 | ;
|
| 1214 | }
|
| 1215 | }
|
| 1216 |
|
| 1217 | |
| 1218 | * ext4_ind_remove_space - remove space from the range
|
| 1219 | * @handle: JBD handle for this transaction
|
| 1220 | * @inode: inode we are dealing with
|
| 1221 | * @start: First block to remove
|
| 1222 | * @end: One block after the last block to remove (exclusive)
|
| 1223 | *
|
| 1224 | * Free the blocks in the defined range (end is exclusive endpoint of
|
| 1225 | * range). This is used by ext4_punch_hole().
|
| 1226 |
|
| 1227 | int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
|
| 1228 | ext4_lblk_t start, ext4_lblk_t end)
|
| 1229 | {
|
| 1230 | struct ext4_inode_info *ei = EXT4_I(inode);
|
| 1231 | __le32 *i_data = ei->i_data;
|
| 1232 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
| 1233 | ext4_lblk_t offsets[4], offsets2[4];
|
| 1234 | Indirect chain[4], chain2[4];
|
| 1235 | Indirect *partial, *partial2;
|
| 1236 | Indirect *p = NULL, *p2 = NULL;
|
| 1237 | ext4_lblk_t max_block;
|
| 1238 | __le32 nr = 0, nr2 = 0;
|
| 1239 | int n = 0, n2 = 0;
|
| 1240 | unsigned blocksize = inode->i_sb->s_blocksize;
|
| 1241 |
|
| 1242 | max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
|
| 1243 | >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
| 1244 | if (end >= max_block)
|
| 1245 | end = max_block;
|
| 1246 | if ((start >= end) || (start > max_block))
|
| 1247 | return 0;
|
| 1248 |
|
| 1249 | n = ext4_block_to_path(inode, start, offsets, NULL);
|
| 1250 | n2 = ext4_block_to_path(inode, end, offsets2, NULL);
|
| 1251 |
|
| 1252 | BUG_ON(n > n2);
|
| 1253 |
|
| 1254 | if ((n == 1) && (n == n2)) {
|
| 1255 |
|
| 1256 | ext4_free_data(handle, inode, NULL, i_data + offsets[0],
|
| 1257 | i_data + offsets2[0]);
|
| 1258 | return 0;
|
| 1259 | } else if (n2 > n) {
|
| 1260 | |
| 1261 | * Start and end are on a different levels so we're going to
|
| 1262 | * free partial block at start, and partial block at end of
|
| 1263 | * the range. If there are some levels in between then
|
| 1264 | * do_indirects label will take care of that.
|
| 1265 |
|
| 1266 |
|
| 1267 | if (n == 1) {
|
| 1268 | |
| 1269 | * Start is at the direct block level, free
|
| 1270 | * everything to the end of the level.
|
| 1271 |
|
| 1272 | ext4_free_data(handle, inode, NULL, i_data + offsets[0],
|
| 1273 | i_data + EXT4_NDIR_BLOCKS);
|
| 1274 | goto end_range;
|
| 1275 | }
|
| 1276 |
|
| 1277 |
|
| 1278 | partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
|
| 1279 | if (nr) {
|
| 1280 | if (partial == chain) {
|
| 1281 |
|
| 1282 | ext4_free_branches(handle, inode, NULL,
|
| 1283 | &nr, &nr+1, (chain+n-1) - partial);
|
| 1284 | *partial->p = 0;
|
| 1285 | } else {
|
| 1286 |
|
| 1287 | BUFFER_TRACE(partial->bh, "get_write_access");
|
| 1288 | ext4_free_branches(handle, inode, partial->bh,
|
| 1289 | partial->p,
|
| 1290 | partial->p+1, (chain+n-1) - partial);
|
| 1291 | }
|
| 1292 | }
|
| 1293 |
|
| 1294 | |
| 1295 | * Clear the ends of indirect blocks on the shared branch
|
| 1296 | * at the start of the range
|
| 1297 |
|
| 1298 | while (partial > chain) {
|
| 1299 | ext4_free_branches(handle, inode, partial->bh,
|
| 1300 | partial->p + 1,
|
| 1301 | (__le32 *)partial->bh->b_data+addr_per_block,
|
| 1302 | (chain+n-1) - partial);
|
| 1303 | partial--;
|
| 1304 | }
|
| 1305 |
|
| 1306 | end_range:
|
| 1307 | partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
|
| 1308 | if (nr2) {
|
| 1309 | if (partial2 == chain2) {
|
| 1310 | |
| 1311 | * Remember, end is exclusive so here we're at
|
| 1312 | * the start of the next level we're not going
|
| 1313 | * to free. Everything was covered by the start
|
| 1314 | * of the range.
|
| 1315 |
|
| 1316 | goto do_indirects;
|
| 1317 | }
|
| 1318 | } else {
|
| 1319 | |
| 1320 | * ext4_find_shared returns Indirect structure which
|
| 1321 | * points to the last element which should not be
|
| 1322 | * removed by truncate. But this is end of the range
|
| 1323 | * in punch_hole so we need to point to the next element
|
| 1324 |
|
| 1325 | partial2->p++;
|
| 1326 | }
|
| 1327 |
|
| 1328 | |
| 1329 | * Clear the ends of indirect blocks on the shared branch
|
| 1330 | * at the end of the range
|
| 1331 |
|
| 1332 | while (partial2 > chain2) {
|
| 1333 | ext4_free_branches(handle, inode, partial2->bh,
|
| 1334 | (__le32 *)partial2->bh->b_data,
|
| 1335 | partial2->p,
|
| 1336 | (chain2+n2-1) - partial2);
|
| 1337 | partial2--;
|
| 1338 | }
|
| 1339 | goto do_indirects;
|
| 1340 | }
|
| 1341 |
|
| 1342 |
|
| 1343 | partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
|
| 1344 | partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
|
| 1345 |
|
| 1346 |
|
| 1347 | if (nr) {
|
| 1348 | int level = min(partial - chain, partial2 - chain2);
|
| 1349 | int i;
|
| 1350 | int subtree = 1;
|
| 1351 |
|
| 1352 | for (i = 0; i <= level; i++) {
|
| 1353 | if (offsets[i] != offsets2[i]) {
|
| 1354 | subtree = 0;
|
| 1355 | break;
|
| 1356 | }
|
| 1357 | }
|
| 1358 |
|
| 1359 | if (!subtree) {
|
| 1360 | if (partial == chain) {
|
| 1361 |
|
| 1362 | ext4_free_branches(handle, inode, NULL,
|
| 1363 | &nr, &nr+1,
|
| 1364 | (chain+n-1) - partial);
|
| 1365 | *partial->p = 0;
|
| 1366 | } else {
|
| 1367 |
|
| 1368 | BUFFER_TRACE(partial->bh, "get_write_access");
|
| 1369 | ext4_free_branches(handle, inode, partial->bh,
|
| 1370 | partial->p,
|
| 1371 | partial->p+1,
|
| 1372 | (chain+n-1) - partial);
|
| 1373 | }
|
| 1374 | }
|
| 1375 | }
|
| 1376 |
|
| 1377 | if (!nr2) {
|
| 1378 | |
| 1379 | * ext4_find_shared returns Indirect structure which
|
| 1380 | * points to the last element which should not be
|
| 1381 | * removed by truncate. But this is end of the range
|
| 1382 | * in punch_hole so we need to point to the next element
|
| 1383 |
|
| 1384 | partial2->p++;
|
| 1385 | }
|
| 1386 |
|
| 1387 | while (partial > chain || partial2 > chain2) {
|
| 1388 | int depth = (chain+n-1) - partial;
|
| 1389 | int depth2 = (chain2+n2-1) - partial2;
|
| 1390 |
|
| 1391 | if (partial > chain && partial2 > chain2 &&
|
| 1392 | partial->bh->b_blocknr == partial2->bh->b_blocknr) {
|
| 1393 | |
| 1394 | * We've converged on the same block. Clear the range,
|
| 1395 | * then we're done.
|
| 1396 |
|
| 1397 | ext4_free_branches(handle, inode, partial->bh,
|
| 1398 | partial->p + 1,
|
| 1399 | partial2->p,
|
| 1400 | (chain+n-1) - partial);
|
| 1401 | goto cleanup;
|
| 1402 | }
|
| 1403 |
|
| 1404 | |
| 1405 | * The start and end partial branches may not be at the same
|
| 1406 | * level even though the punch happened within one level. So, we
|
| 1407 | * give them a chance to arrive at the same level, then walk
|
| 1408 | * them in step with each other until we converge on the same
|
| 1409 | * block.
|
| 1410 |
|
| 1411 | if (partial > chain && depth <= depth2) {
|
| 1412 | ext4_free_branches(handle, inode, partial->bh,
|
| 1413 | partial->p + 1,
|
| 1414 | (__le32 *)partial->bh->b_data+addr_per_block,
|
| 1415 | (chain+n-1) - partial);
|
| 1416 | partial--;
|
| 1417 | }
|
| 1418 | if (partial2 > chain2 && depth2 <= depth) {
|
| 1419 | ext4_free_branches(handle, inode, partial2->bh,
|
| 1420 | (__le32 *)partial2->bh->b_data,
|
| 1421 | partial2->p,
|
| 1422 | (chain2+n2-1) - partial2);
|
| 1423 | partial2--;
|
| 1424 | }
|
| 1425 | }
|
| 1426 |
|
| 1427 | cleanup:
|
| 1428 | while (p && p > chain) {
|
| 1429 | BUFFER_TRACE(p->bh, "call brelse");
|
| 1430 | brelse(p->bh);
|
| 1431 | p--;
|
| 1432 | }
|
| 1433 | while (p2 && p2 > chain2) {
|
| 1434 | BUFFER_TRACE(p2->bh, "call brelse");
|
| 1435 | brelse(p2->bh);
|
| 1436 | p2--;
|
| 1437 | }
|
| 1438 | return 0;
|
| 1439 |
|
| 1440 | do_indirects:
|
| 1441 |
|
| 1442 | switch (offsets[0]) {
|
| 1443 | default:
|
| 1444 | if (++n >= n2)
|
| 1445 | break;
|
| 1446 | nr = i_data[EXT4_IND_BLOCK];
|
| 1447 | if (nr) {
|
| 1448 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
|
| 1449 | i_data[EXT4_IND_BLOCK] = 0;
|
| 1450 | }
|
| 1451 | fallthrough;
|
| 1452 | case EXT4_IND_BLOCK:
|
| 1453 | if (++n >= n2)
|
| 1454 | break;
|
| 1455 | nr = i_data[EXT4_DIND_BLOCK];
|
| 1456 | if (nr) {
|
| 1457 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
|
| 1458 | i_data[EXT4_DIND_BLOCK] = 0;
|
| 1459 | }
|
| 1460 | fallthrough;
|
| 1461 | case EXT4_DIND_BLOCK:
|
| 1462 | if (++n >= n2)
|
| 1463 | break;
|
| 1464 | nr = i_data[EXT4_TIND_BLOCK];
|
| 1465 | if (nr) {
|
| 1466 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
|
| 1467 | i_data[EXT4_TIND_BLOCK] = 0;
|
| 1468 | }
|
| 1469 | fallthrough;
|
| 1470 | case EXT4_TIND_BLOCK:
|
| 1471 | ;
|
| 1472 | }
|
| 1473 | goto cleanup;
|
| 1474 | }
|