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Amir Goldsteindae1e522011-06-27 19:40:50 -04001/*
2 * linux/fs/ext4/indirect.c
3 *
4 * from
5 *
6 * linux/fs/ext4/inode.c
7 *
8 * Copyright (C) 1992, 1993, 1994, 1995
9 * Remy Card (card@masi.ibp.fr)
10 * Laboratoire MASI - Institut Blaise Pascal
11 * Universite Pierre et Marie Curie (Paris VI)
12 *
13 * from
14 *
15 * linux/fs/minix/inode.c
16 *
17 * Copyright (C) 1991, 1992 Linus Torvalds
18 *
19 * Goal-directed block allocation by Stephen Tweedie
20 * (sct@redhat.com), 1993, 1998
21 */
22
Kent Overstreeta27bb332013-05-07 16:19:08 -070023#include <linux/aio.h>
Amir Goldsteindae1e522011-06-27 19:40:50 -040024#include "ext4_jbd2.h"
25#include "truncate.h"
26
27#include <trace/events/ext4.h>
28
29typedef struct {
30 __le32 *p;
31 __le32 key;
32 struct buffer_head *bh;
33} Indirect;
34
35static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
36{
37 p->key = *(p->p = v);
38 p->bh = bh;
39}
40
41/**
42 * ext4_block_to_path - parse the block number into array of offsets
43 * @inode: inode in question (we are only interested in its superblock)
44 * @i_block: block number to be parsed
45 * @offsets: array to store the offsets in
46 * @boundary: set this non-zero if the referred-to block is likely to be
47 * followed (on disk) by an indirect block.
48 *
49 * To store the locations of file's data ext4 uses a data structure common
50 * for UNIX filesystems - tree of pointers anchored in the inode, with
51 * data blocks at leaves and indirect blocks in intermediate nodes.
52 * This function translates the block number into path in that tree -
53 * return value is the path length and @offsets[n] is the offset of
54 * pointer to (n+1)th node in the nth one. If @block is out of range
55 * (negative or too large) warning is printed and zero returned.
56 *
57 * Note: function doesn't find node addresses, so no IO is needed. All
58 * we need to know is the capacity of indirect blocks (taken from the
59 * inode->i_sb).
60 */
61
62/*
63 * Portability note: the last comparison (check that we fit into triple
64 * indirect block) is spelled differently, because otherwise on an
65 * architecture with 32-bit longs and 8Kb pages we might get into trouble
66 * if our filesystem had 8Kb blocks. We might use long long, but that would
67 * kill us on x86. Oh, well, at least the sign propagation does not matter -
68 * i_block would have to be negative in the very beginning, so we would not
69 * get there at all.
70 */
71
72static int ext4_block_to_path(struct inode *inode,
73 ext4_lblk_t i_block,
74 ext4_lblk_t offsets[4], int *boundary)
75{
76 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
77 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
78 const long direct_blocks = EXT4_NDIR_BLOCKS,
79 indirect_blocks = ptrs,
80 double_blocks = (1 << (ptrs_bits * 2));
81 int n = 0;
82 int final = 0;
83
84 if (i_block < direct_blocks) {
85 offsets[n++] = i_block;
86 final = direct_blocks;
87 } else if ((i_block -= direct_blocks) < indirect_blocks) {
88 offsets[n++] = EXT4_IND_BLOCK;
89 offsets[n++] = i_block;
90 final = ptrs;
91 } else if ((i_block -= indirect_blocks) < double_blocks) {
92 offsets[n++] = EXT4_DIND_BLOCK;
93 offsets[n++] = i_block >> ptrs_bits;
94 offsets[n++] = i_block & (ptrs - 1);
95 final = ptrs;
96 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
97 offsets[n++] = EXT4_TIND_BLOCK;
98 offsets[n++] = i_block >> (ptrs_bits * 2);
99 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
100 offsets[n++] = i_block & (ptrs - 1);
101 final = ptrs;
102 } else {
103 ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
104 i_block + direct_blocks +
105 indirect_blocks + double_blocks, inode->i_ino);
106 }
107 if (boundary)
108 *boundary = final - 1 - (i_block & (ptrs - 1));
109 return n;
110}
111
112/**
113 * ext4_get_branch - read the chain of indirect blocks leading to data
114 * @inode: inode in question
115 * @depth: depth of the chain (1 - direct pointer, etc.)
116 * @offsets: offsets of pointers in inode/indirect blocks
117 * @chain: place to store the result
118 * @err: here we store the error value
119 *
120 * Function fills the array of triples <key, p, bh> and returns %NULL
121 * if everything went OK or the pointer to the last filled triple
122 * (incomplete one) otherwise. Upon the return chain[i].key contains
123 * the number of (i+1)-th block in the chain (as it is stored in memory,
124 * i.e. little-endian 32-bit), chain[i].p contains the address of that
125 * number (it points into struct inode for i==0 and into the bh->b_data
126 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
127 * block for i>0 and NULL for i==0. In other words, it holds the block
128 * numbers of the chain, addresses they were taken from (and where we can
129 * verify that chain did not change) and buffer_heads hosting these
130 * numbers.
131 *
132 * Function stops when it stumbles upon zero pointer (absent block)
133 * (pointer to last triple returned, *@err == 0)
134 * or when it gets an IO error reading an indirect block
135 * (ditto, *@err == -EIO)
136 * or when it reads all @depth-1 indirect blocks successfully and finds
137 * the whole chain, all way to the data (returns %NULL, *err == 0).
138 *
139 * Need to be called with
140 * down_read(&EXT4_I(inode)->i_data_sem)
141 */
142static Indirect *ext4_get_branch(struct inode *inode, int depth,
143 ext4_lblk_t *offsets,
144 Indirect chain[4], int *err)
145{
146 struct super_block *sb = inode->i_sb;
147 Indirect *p = chain;
148 struct buffer_head *bh;
Theodore Ts'o860d21e2013-01-12 16:19:36 -0500149 int ret = -EIO;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400150
151 *err = 0;
152 /* i_data is not going away, no lock needed */
153 add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
154 if (!p->key)
155 goto no_block;
156 while (--depth) {
157 bh = sb_getblk(sb, le32_to_cpu(p->key));
Theodore Ts'o860d21e2013-01-12 16:19:36 -0500158 if (unlikely(!bh)) {
159 ret = -ENOMEM;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400160 goto failure;
Theodore Ts'o860d21e2013-01-12 16:19:36 -0500161 }
Amir Goldsteindae1e522011-06-27 19:40:50 -0400162
163 if (!bh_uptodate_or_lock(bh)) {
164 if (bh_submit_read(bh) < 0) {
165 put_bh(bh);
166 goto failure;
167 }
168 /* validate block references */
169 if (ext4_check_indirect_blockref(inode, bh)) {
170 put_bh(bh);
171 goto failure;
172 }
173 }
174
175 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
176 /* Reader: end */
177 if (!p->key)
178 goto no_block;
179 }
180 return NULL;
181
182failure:
Theodore Ts'o860d21e2013-01-12 16:19:36 -0500183 *err = ret;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400184no_block:
185 return p;
186}
187
188/**
189 * ext4_find_near - find a place for allocation with sufficient locality
190 * @inode: owner
191 * @ind: descriptor of indirect block.
192 *
193 * This function returns the preferred place for block allocation.
194 * It is used when heuristic for sequential allocation fails.
195 * Rules are:
196 * + if there is a block to the left of our position - allocate near it.
197 * + if pointer will live in indirect block - allocate near that block.
198 * + if pointer will live in inode - allocate in the same
199 * cylinder group.
200 *
201 * In the latter case we colour the starting block by the callers PID to
202 * prevent it from clashing with concurrent allocations for a different inode
203 * in the same block group. The PID is used here so that functionally related
204 * files will be close-by on-disk.
205 *
206 * Caller must make sure that @ind is valid and will stay that way.
207 */
208static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
209{
210 struct ext4_inode_info *ei = EXT4_I(inode);
211 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
212 __le32 *p;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400213
214 /* Try to find previous block */
215 for (p = ind->p - 1; p >= start; p--) {
216 if (*p)
217 return le32_to_cpu(*p);
218 }
219
220 /* No such thing, so let's try location of indirect block */
221 if (ind->bh)
222 return ind->bh->b_blocknr;
223
224 /*
225 * It is going to be referred to from the inode itself? OK, just put it
226 * into the same cylinder group then.
227 */
Eric Sandeenf86186b2011-06-28 10:01:31 -0400228 return ext4_inode_to_goal_block(inode);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400229}
230
231/**
232 * ext4_find_goal - find a preferred place for allocation.
233 * @inode: owner
234 * @block: block we want
235 * @partial: pointer to the last triple within a chain
236 *
237 * Normally this function find the preferred place for block allocation,
238 * returns it.
239 * Because this is only used for non-extent files, we limit the block nr
240 * to 32 bits.
241 */
242static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
243 Indirect *partial)
244{
245 ext4_fsblk_t goal;
246
247 /*
248 * XXX need to get goal block from mballoc's data structures
249 */
250
251 goal = ext4_find_near(inode, partial);
252 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
253 return goal;
254}
255
256/**
257 * ext4_blks_to_allocate - Look up the block map and count the number
258 * of direct blocks need to be allocated for the given branch.
259 *
260 * @branch: chain of indirect blocks
261 * @k: number of blocks need for indirect blocks
262 * @blks: number of data blocks to be mapped.
263 * @blocks_to_boundary: the offset in the indirect block
264 *
265 * return the total number of blocks to be allocate, including the
266 * direct and indirect blocks.
267 */
268static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
269 int blocks_to_boundary)
270{
271 unsigned int count = 0;
272
273 /*
274 * Simple case, [t,d]Indirect block(s) has not allocated yet
275 * then it's clear blocks on that path have not allocated
276 */
277 if (k > 0) {
278 /* right now we don't handle cross boundary allocation */
279 if (blks < blocks_to_boundary + 1)
280 count += blks;
281 else
282 count += blocks_to_boundary + 1;
283 return count;
284 }
285
286 count++;
287 while (count < blks && count <= blocks_to_boundary &&
288 le32_to_cpu(*(branch[0].p + count)) == 0) {
289 count++;
290 }
291 return count;
292}
293
294/**
Amir Goldsteindae1e522011-06-27 19:40:50 -0400295 * ext4_alloc_branch - allocate and set up a chain of blocks.
296 * @handle: handle for this transaction
297 * @inode: owner
298 * @indirect_blks: number of allocated indirect blocks
299 * @blks: number of allocated direct blocks
300 * @goal: preferred place for allocation
301 * @offsets: offsets (in the blocks) to store the pointers to next.
302 * @branch: place to store the chain in.
303 *
304 * This function allocates blocks, zeroes out all but the last one,
305 * links them into chain and (if we are synchronous) writes them to disk.
306 * In other words, it prepares a branch that can be spliced onto the
307 * inode. It stores the information about that chain in the branch[], in
308 * the same format as ext4_get_branch() would do. We are calling it after
309 * we had read the existing part of chain and partial points to the last
310 * triple of that (one with zero ->key). Upon the exit we have the same
311 * picture as after the successful ext4_get_block(), except that in one
312 * place chain is disconnected - *branch->p is still zero (we did not
313 * set the last link), but branch->key contains the number that should
314 * be placed into *branch->p to fill that gap.
315 *
316 * If allocation fails we free all blocks we've allocated (and forget
317 * their buffer_heads) and return the error value the from failed
318 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
319 * as described above and return 0.
320 */
321static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
322 ext4_lblk_t iblock, int indirect_blks,
323 int *blks, ext4_fsblk_t goal,
324 ext4_lblk_t *offsets, Indirect *branch)
325{
Theodore Ts'o781f1432013-04-03 12:43:17 -0400326 struct ext4_allocation_request ar;
327 struct buffer_head * bh;
328 ext4_fsblk_t b, new_blocks[4];
329 __le32 *p;
330 int i, j, err, len = 1;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400331
Amir Goldsteindae1e522011-06-27 19:40:50 -0400332 /*
Theodore Ts'o781f1432013-04-03 12:43:17 -0400333 * Set up for the direct block allocation
Amir Goldsteindae1e522011-06-27 19:40:50 -0400334 */
Theodore Ts'o781f1432013-04-03 12:43:17 -0400335 memset(&ar, 0, sizeof(ar));
336 ar.inode = inode;
337 ar.len = *blks;
338 ar.logical = iblock;
339 if (S_ISREG(inode->i_mode))
340 ar.flags = EXT4_MB_HINT_DATA;
341
342 for (i = 0; i <= indirect_blks; i++) {
343 if (i == indirect_blks) {
344 ar.goal = goal;
345 new_blocks[i] = ext4_mb_new_blocks(handle, &ar, &err);
346 } else
347 goal = new_blocks[i] = ext4_new_meta_blocks(handle, inode,
348 goal, 0, NULL, &err);
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(inode->i_sb, new_blocks[i-1]);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400358 if (unlikely(!bh)) {
Theodore Ts'o860d21e2013-01-12 16:19:36 -0500359 err = -ENOMEM;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400360 goto failed;
361 }
Amir Goldsteindae1e522011-06-27 19:40:50 -0400362 lock_buffer(bh);
363 BUFFER_TRACE(bh, "call get_create_access");
364 err = ext4_journal_get_create_access(handle, bh);
365 if (err) {
Amir Goldsteindae1e522011-06-27 19:40:50 -0400366 unlock_buffer(bh);
367 goto failed;
368 }
369
Theodore Ts'o781f1432013-04-03 12:43:17 -0400370 memset(bh->b_data, 0, bh->b_size);
371 p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
372 b = new_blocks[i];
373
374 if (i == indirect_blks)
375 len = ar.len;
376 for (j = 0; j < len; j++)
377 *p++ = cpu_to_le32(b++);
378
Amir Goldsteindae1e522011-06-27 19:40:50 -0400379 BUFFER_TRACE(bh, "marking uptodate");
380 set_buffer_uptodate(bh);
381 unlock_buffer(bh);
382
383 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
384 err = ext4_handle_dirty_metadata(handle, inode, bh);
385 if (err)
386 goto failed;
387 }
Theodore Ts'o781f1432013-04-03 12:43:17 -0400388 *blks = ar.len;
389 return 0;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400390failed:
Theodore Ts'o781f1432013-04-03 12:43:17 -0400391 for (; i >= 0; i--) {
Jan Karac5c7b8d2014-06-15 23:46:28 -0400392 /*
393 * We want to ext4_forget() only freshly allocated indirect
394 * blocks. Buffer for new_blocks[i-1] is at branch[i].bh and
395 * buffer at branch[0].bh is indirect block / inode already
396 * existing before ext4_alloc_branch() was called.
397 */
398 if (i > 0 && i != indirect_blks && branch[i].bh)
Theodore Ts'o781f1432013-04-03 12:43:17 -0400399 ext4_forget(handle, 1, inode, branch[i].bh,
400 branch[i].bh->b_blocknr);
401 ext4_free_blocks(handle, inode, NULL, new_blocks[i],
402 (i == indirect_blks) ? ar.len : 1, 0);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400403 }
Amir Goldsteindae1e522011-06-27 19:40:50 -0400404 return err;
405}
406
407/**
408 * ext4_splice_branch - splice the allocated branch onto inode.
409 * @handle: handle for this transaction
410 * @inode: owner
411 * @block: (logical) number of block we are adding
412 * @chain: chain of indirect blocks (with a missing link - see
413 * ext4_alloc_branch)
414 * @where: location of missing link
415 * @num: number of indirect blocks we are adding
416 * @blks: number of direct blocks we are adding
417 *
418 * This function fills the missing link and does all housekeeping needed in
419 * inode (->i_blocks, etc.). In case of success we end up with the full
420 * chain to new block and return 0.
421 */
422static int ext4_splice_branch(handle_t *handle, struct inode *inode,
423 ext4_lblk_t block, Indirect *where, int num,
424 int blks)
425{
426 int i;
427 int err = 0;
428 ext4_fsblk_t current_block;
429
430 /*
431 * If we're splicing into a [td]indirect block (as opposed to the
432 * inode) then we need to get write access to the [td]indirect block
433 * before the splice.
434 */
435 if (where->bh) {
436 BUFFER_TRACE(where->bh, "get_write_access");
437 err = ext4_journal_get_write_access(handle, where->bh);
438 if (err)
439 goto err_out;
440 }
441 /* That's it */
442
443 *where->p = where->key;
444
445 /*
446 * Update the host buffer_head or inode to point to more just allocated
447 * direct blocks blocks
448 */
449 if (num == 0 && blks > 1) {
450 current_block = le32_to_cpu(where->key) + 1;
451 for (i = 1; i < blks; i++)
452 *(where->p + i) = cpu_to_le32(current_block++);
453 }
454
455 /* We are done with atomic stuff, now do the rest of housekeeping */
456 /* had we spliced it onto indirect block? */
457 if (where->bh) {
458 /*
459 * If we spliced it onto an indirect block, we haven't
460 * altered the inode. Note however that if it is being spliced
461 * onto an indirect block at the very end of the file (the
462 * file is growing) then we *will* alter the inode to reflect
463 * the new i_size. But that is not done here - it is done in
464 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
465 */
466 jbd_debug(5, "splicing indirect only\n");
467 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
468 err = ext4_handle_dirty_metadata(handle, inode, where->bh);
469 if (err)
470 goto err_out;
471 } else {
472 /*
473 * OK, we spliced it into the inode itself on a direct block.
474 */
475 ext4_mark_inode_dirty(handle, inode);
476 jbd_debug(5, "splicing direct\n");
477 }
478 return err;
479
480err_out:
481 for (i = 1; i <= num; i++) {
482 /*
483 * branch[i].bh is newly allocated, so there is no
484 * need to revoke the block, which is why we don't
485 * need to set EXT4_FREE_BLOCKS_METADATA.
486 */
487 ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
488 EXT4_FREE_BLOCKS_FORGET);
489 }
490 ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key),
491 blks, 0);
492
493 return err;
494}
495
496/*
497 * The ext4_ind_map_blocks() function handles non-extents inodes
498 * (i.e., using the traditional indirect/double-indirect i_blocks
499 * scheme) for ext4_map_blocks().
500 *
501 * Allocation strategy is simple: if we have to allocate something, we will
502 * have to go the whole way to leaf. So let's do it before attaching anything
503 * to tree, set linkage between the newborn blocks, write them if sync is
504 * required, recheck the path, free and repeat if check fails, otherwise
505 * set the last missing link (that will protect us from any truncate-generated
506 * removals - all blocks on the path are immune now) and possibly force the
507 * write on the parent block.
508 * That has a nice additional property: no special recovery from the failed
509 * allocations is needed - we simply release blocks and do not touch anything
510 * reachable from inode.
511 *
512 * `handle' can be NULL if create == 0.
513 *
514 * return > 0, # of blocks mapped or allocated.
515 * return = 0, if plain lookup failed.
516 * return < 0, error case.
517 *
518 * The ext4_ind_get_blocks() function should be called with
519 * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
520 * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
521 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
522 * blocks.
523 */
524int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
525 struct ext4_map_blocks *map,
526 int flags)
527{
528 int err = -EIO;
529 ext4_lblk_t offsets[4];
530 Indirect chain[4];
531 Indirect *partial;
532 ext4_fsblk_t goal;
533 int indirect_blks;
534 int blocks_to_boundary = 0;
535 int depth;
536 int count = 0;
537 ext4_fsblk_t first_block = 0;
538
539 trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
540 J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
541 J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
542 depth = ext4_block_to_path(inode, map->m_lblk, offsets,
543 &blocks_to_boundary);
544
545 if (depth == 0)
546 goto out;
547
548 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
549
550 /* Simplest case - block found, no allocation needed */
551 if (!partial) {
552 first_block = le32_to_cpu(chain[depth - 1].key);
553 count++;
554 /*map more blocks*/
555 while (count < map->m_len && count <= blocks_to_boundary) {
556 ext4_fsblk_t blk;
557
558 blk = le32_to_cpu(*(chain[depth-1].p + count));
559
560 if (blk == first_block + count)
561 count++;
562 else
563 break;
564 }
565 goto got_it;
566 }
567
568 /* Next simple case - plain lookup or failed read of indirect block */
569 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
570 goto cleanup;
571
572 /*
573 * Okay, we need to do block allocation.
574 */
Theodore Ts'obab08ab2011-09-09 18:36:51 -0400575 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
576 EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
577 EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
578 "non-extent mapped inodes with bigalloc");
579 return -ENOSPC;
580 }
581
Amir Goldsteindae1e522011-06-27 19:40:50 -0400582 goal = ext4_find_goal(inode, map->m_lblk, partial);
583
584 /* the number of blocks need to allocate for [d,t]indirect blocks */
585 indirect_blks = (chain + depth) - partial - 1;
586
587 /*
588 * Next look up the indirect map to count the totoal number of
589 * direct blocks to allocate for this branch.
590 */
591 count = ext4_blks_to_allocate(partial, indirect_blks,
592 map->m_len, blocks_to_boundary);
593 /*
594 * Block out ext4_truncate while we alter the tree
595 */
596 err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks,
597 &count, goal,
598 offsets + (partial - chain), partial);
599
600 /*
601 * The ext4_splice_branch call will free and forget any buffers
602 * on the new chain if there is a failure, but that risks using
603 * up transaction credits, especially for bitmaps where the
604 * credits cannot be returned. Can we handle this somehow? We
605 * may need to return -EAGAIN upwards in the worst case. --sct
606 */
607 if (!err)
608 err = ext4_splice_branch(handle, inode, map->m_lblk,
609 partial, indirect_blks, count);
610 if (err)
611 goto cleanup;
612
613 map->m_flags |= EXT4_MAP_NEW;
614
615 ext4_update_inode_fsync_trans(handle, inode, 1);
616got_it:
617 map->m_flags |= EXT4_MAP_MAPPED;
618 map->m_pblk = le32_to_cpu(chain[depth-1].key);
619 map->m_len = count;
620 if (count > blocks_to_boundary)
621 map->m_flags |= EXT4_MAP_BOUNDARY;
622 err = count;
623 /* Clean up and exit */
624 partial = chain + depth - 1; /* the whole chain */
625cleanup:
626 while (partial > chain) {
627 BUFFER_TRACE(partial->bh, "call brelse");
628 brelse(partial->bh);
629 partial--;
630 }
631out:
Theodore Ts'o21ddd562013-07-01 08:12:40 -0400632 trace_ext4_ind_map_blocks_exit(inode, flags, map, err);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400633 return err;
634}
635
636/*
637 * O_DIRECT for ext3 (or indirect map) based files
638 *
639 * If the O_DIRECT write will extend the file then add this inode to the
640 * orphan list. So recovery will truncate it back to the original size
641 * if the machine crashes during the write.
642 *
643 * If the O_DIRECT write is intantiating holes inside i_size and the machine
644 * crashes then stale disk data _may_ be exposed inside the file. But current
645 * VFS code falls back into buffered path in that case so we are safe.
646 */
647ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
Al Viro16b1f052014-03-04 22:14:00 -0500648 struct iov_iter *iter, loff_t offset)
Amir Goldsteindae1e522011-06-27 19:40:50 -0400649{
650 struct file *file = iocb->ki_filp;
651 struct inode *inode = file->f_mapping->host;
652 struct ext4_inode_info *ei = EXT4_I(inode);
653 handle_t *handle;
654 ssize_t ret;
655 int orphan = 0;
Al Viroa6cbcd42014-03-04 22:38:00 -0500656 size_t count = iov_iter_count(iter);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400657 int retries = 0;
658
659 if (rw == WRITE) {
660 loff_t final_size = offset + count;
661
662 if (final_size > inode->i_size) {
663 /* Credits for sb + inode write */
Theodore Ts'o9924a922013-02-08 21:59:22 -0500664 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400665 if (IS_ERR(handle)) {
666 ret = PTR_ERR(handle);
667 goto out;
668 }
669 ret = ext4_orphan_add(handle, inode);
670 if (ret) {
671 ext4_journal_stop(handle);
672 goto out;
673 }
674 orphan = 1;
675 ei->i_disksize = inode->i_size;
676 ext4_journal_stop(handle);
677 }
678 }
679
680retry:
Jiaying Zhangdccaf332011-08-19 19:13:32 -0400681 if (rw == READ && ext4_should_dioread_nolock(inode)) {
Dmitry Monakhov17335dc2012-09-29 00:41:21 -0400682 /*
683 * Nolock dioread optimization may be dynamically disabled
684 * via ext4_inode_block_unlocked_dio(). Check inode's state
685 * while holding extra i_dio_count ref.
686 */
687 atomic_inc(&inode->i_dio_count);
688 smp_mb();
689 if (unlikely(ext4_test_inode_state(inode,
690 EXT4_STATE_DIOREAD_LOCK))) {
691 inode_dio_done(inode);
692 goto locked;
693 }
Amir Goldsteindae1e522011-06-27 19:40:50 -0400694 ret = __blockdev_direct_IO(rw, iocb, inode,
Al Viro31b14032014-03-05 01:33:16 -0500695 inode->i_sb->s_bdev, iter, offset,
Amir Goldsteindae1e522011-06-27 19:40:50 -0400696 ext4_get_block, NULL, NULL, 0);
Dmitry Monakhov17335dc2012-09-29 00:41:21 -0400697 inode_dio_done(inode);
Jiaying Zhangdccaf332011-08-19 19:13:32 -0400698 } else {
Dmitry Monakhov17335dc2012-09-29 00:41:21 -0400699locked:
Al Viro31b14032014-03-05 01:33:16 -0500700 ret = blockdev_direct_IO(rw, iocb, inode, iter,
701 offset, ext4_get_block);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400702
703 if (unlikely((rw & WRITE) && ret < 0)) {
704 loff_t isize = i_size_read(inode);
Al Viro16b1f052014-03-04 22:14:00 -0500705 loff_t end = offset + count;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400706
707 if (end > isize)
708 ext4_truncate_failed_write(inode);
709 }
710 }
711 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
712 goto retry;
713
714 if (orphan) {
715 int err;
716
717 /* Credits for sb + inode write */
Theodore Ts'o9924a922013-02-08 21:59:22 -0500718 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
Amir Goldsteindae1e522011-06-27 19:40:50 -0400719 if (IS_ERR(handle)) {
720 /* This is really bad luck. We've written the data
721 * but cannot extend i_size. Bail out and pretend
722 * the write failed... */
723 ret = PTR_ERR(handle);
724 if (inode->i_nlink)
725 ext4_orphan_del(NULL, inode);
726
727 goto out;
728 }
729 if (inode->i_nlink)
730 ext4_orphan_del(handle, inode);
731 if (ret > 0) {
732 loff_t end = offset + ret;
733 if (end > inode->i_size) {
734 ei->i_disksize = end;
735 i_size_write(inode, end);
736 /*
737 * We're going to return a positive `ret'
738 * here due to non-zero-length I/O, so there's
739 * no way of reporting error returns from
740 * ext4_mark_inode_dirty() to userspace. So
741 * ignore it.
742 */
743 ext4_mark_inode_dirty(handle, inode);
744 }
745 }
746 err = ext4_journal_stop(handle);
747 if (ret == 0)
748 ret = err;
749 }
750out:
751 return ret;
752}
753
754/*
755 * Calculate the number of metadata blocks need to reserve
756 * to allocate a new block at @lblocks for non extent file based file
757 */
758int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
759{
760 struct ext4_inode_info *ei = EXT4_I(inode);
761 sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
762 int blk_bits;
763
764 if (lblock < EXT4_NDIR_BLOCKS)
765 return 0;
766
767 lblock -= EXT4_NDIR_BLOCKS;
768
769 if (ei->i_da_metadata_calc_len &&
770 (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
771 ei->i_da_metadata_calc_len++;
772 return 0;
773 }
774 ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
775 ei->i_da_metadata_calc_len = 1;
776 blk_bits = order_base_2(lblock);
777 return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
778}
779
Jan Karafa55a0e2013-06-04 12:56:55 -0400780/*
781 * Calculate number of indirect blocks touched by mapping @nrblocks logically
782 * contiguous blocks
783 */
784int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
Amir Goldsteindae1e522011-06-27 19:40:50 -0400785{
Amir Goldsteindae1e522011-06-27 19:40:50 -0400786 /*
Jan Karafa55a0e2013-06-04 12:56:55 -0400787 * With N contiguous data blocks, we need at most
788 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
789 * 2 dindirect blocks, and 1 tindirect block
Amir Goldsteindae1e522011-06-27 19:40:50 -0400790 */
Jan Karafa55a0e2013-06-04 12:56:55 -0400791 return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400792}
793
794/*
795 * Truncate transactions can be complex and absolutely huge. So we need to
796 * be able to restart the transaction at a conventient checkpoint to make
797 * sure we don't overflow the journal.
798 *
Theodore Ts'o819c4922013-04-03 12:47:17 -0400799 * Try to extend this transaction for the purposes of truncation. If
Amir Goldsteindae1e522011-06-27 19:40:50 -0400800 * extend fails, we need to propagate the failure up and restart the
801 * transaction in the top-level truncate loop. --sct
Amir Goldsteindae1e522011-06-27 19:40:50 -0400802 *
803 * Returns 0 if we managed to create more room. If we can't create more
804 * room, and the transaction must be restarted we return 1.
805 */
806static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
807{
808 if (!ext4_handle_valid(handle))
809 return 0;
810 if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
811 return 0;
812 if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode)))
813 return 0;
814 return 1;
815}
816
817/*
818 * Probably it should be a library function... search for first non-zero word
819 * or memcmp with zero_page, whatever is better for particular architecture.
820 * Linus?
821 */
822static inline int all_zeroes(__le32 *p, __le32 *q)
823{
824 while (p < q)
825 if (*p++)
826 return 0;
827 return 1;
828}
829
830/**
831 * ext4_find_shared - find the indirect blocks for partial truncation.
832 * @inode: inode in question
833 * @depth: depth of the affected branch
834 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
835 * @chain: place to store the pointers to partial indirect blocks
836 * @top: place to the (detached) top of branch
837 *
838 * This is a helper function used by ext4_truncate().
839 *
840 * When we do truncate() we may have to clean the ends of several
841 * indirect blocks but leave the blocks themselves alive. Block is
842 * partially truncated if some data below the new i_size is referred
843 * from it (and it is on the path to the first completely truncated
844 * data block, indeed). We have to free the top of that path along
845 * with everything to the right of the path. Since no allocation
846 * past the truncation point is possible until ext4_truncate()
847 * finishes, we may safely do the latter, but top of branch may
848 * require special attention - pageout below the truncation point
849 * might try to populate it.
850 *
851 * We atomically detach the top of branch from the tree, store the
852 * block number of its root in *@top, pointers to buffer_heads of
853 * partially truncated blocks - in @chain[].bh and pointers to
854 * their last elements that should not be removed - in
855 * @chain[].p. Return value is the pointer to last filled element
856 * of @chain.
857 *
858 * The work left to caller to do the actual freeing of subtrees:
859 * a) free the subtree starting from *@top
860 * b) free the subtrees whose roots are stored in
861 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
862 * c) free the subtrees growing from the inode past the @chain[0].
863 * (no partially truncated stuff there). */
864
865static Indirect *ext4_find_shared(struct inode *inode, int depth,
866 ext4_lblk_t offsets[4], Indirect chain[4],
867 __le32 *top)
868{
869 Indirect *partial, *p;
870 int k, err;
871
872 *top = 0;
873 /* Make k index the deepest non-null offset + 1 */
874 for (k = depth; k > 1 && !offsets[k-1]; k--)
875 ;
876 partial = ext4_get_branch(inode, k, offsets, chain, &err);
877 /* Writer: pointers */
878 if (!partial)
879 partial = chain + k-1;
880 /*
881 * If the branch acquired continuation since we've looked at it -
882 * fine, it should all survive and (new) top doesn't belong to us.
883 */
884 if (!partial->key && *partial->p)
885 /* Writer: end */
886 goto no_top;
887 for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
888 ;
889 /*
890 * OK, we've found the last block that must survive. The rest of our
891 * branch should be detached before unlocking. However, if that rest
892 * of branch is all ours and does not grow immediately from the inode
893 * it's easier to cheat and just decrement partial->p.
894 */
895 if (p == chain + k - 1 && p > chain) {
896 p->p--;
897 } else {
898 *top = *p->p;
899 /* Nope, don't do this in ext4. Must leave the tree intact */
900#if 0
901 *p->p = 0;
902#endif
903 }
904 /* Writer: end */
905
906 while (partial > p) {
907 brelse(partial->bh);
908 partial--;
909 }
910no_top:
911 return partial;
912}
913
914/*
915 * Zero a number of block pointers in either an inode or an indirect block.
916 * If we restart the transaction we must again get write access to the
917 * indirect block for further modification.
918 *
919 * We release `count' blocks on disk, but (last - first) may be greater
920 * than `count' because there can be holes in there.
921 *
922 * Return 0 on success, 1 on invalid block range
923 * and < 0 on fatal error.
924 */
925static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
926 struct buffer_head *bh,
927 ext4_fsblk_t block_to_free,
928 unsigned long count, __le32 *first,
929 __le32 *last)
930{
931 __le32 *p;
Theodore Ts'o981250c2013-06-12 11:48:29 -0400932 int flags = EXT4_FREE_BLOCKS_VALIDATED;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400933 int err;
934
935 if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
Theodore Ts'o981250c2013-06-12 11:48:29 -0400936 flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
937 else if (ext4_should_journal_data(inode))
938 flags |= EXT4_FREE_BLOCKS_FORGET;
Amir Goldsteindae1e522011-06-27 19:40:50 -0400939
940 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
941 count)) {
942 EXT4_ERROR_INODE(inode, "attempt to clear invalid "
943 "blocks %llu len %lu",
944 (unsigned long long) block_to_free, count);
945 return 1;
946 }
947
948 if (try_to_extend_transaction(handle, inode)) {
949 if (bh) {
950 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
951 err = ext4_handle_dirty_metadata(handle, inode, bh);
952 if (unlikely(err))
953 goto out_err;
954 }
955 err = ext4_mark_inode_dirty(handle, inode);
956 if (unlikely(err))
957 goto out_err;
958 err = ext4_truncate_restart_trans(handle, inode,
959 ext4_blocks_for_truncate(inode));
960 if (unlikely(err))
961 goto out_err;
962 if (bh) {
963 BUFFER_TRACE(bh, "retaking write access");
964 err = ext4_journal_get_write_access(handle, bh);
965 if (unlikely(err))
966 goto out_err;
967 }
968 }
969
970 for (p = first; p < last; p++)
971 *p = 0;
972
973 ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
974 return 0;
975out_err:
976 ext4_std_error(inode->i_sb, err);
977 return err;
978}
979
980/**
981 * ext4_free_data - free a list of data blocks
982 * @handle: handle for this transaction
983 * @inode: inode we are dealing with
984 * @this_bh: indirect buffer_head which contains *@first and *@last
985 * @first: array of block numbers
986 * @last: points immediately past the end of array
987 *
988 * We are freeing all blocks referred from that array (numbers are stored as
989 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
990 *
991 * We accumulate contiguous runs of blocks to free. Conveniently, if these
992 * blocks are contiguous then releasing them at one time will only affect one
993 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
994 * actually use a lot of journal space.
995 *
996 * @this_bh will be %NULL if @first and @last point into the inode's direct
997 * block pointers.
998 */
999static void ext4_free_data(handle_t *handle, struct inode *inode,
1000 struct buffer_head *this_bh,
1001 __le32 *first, __le32 *last)
1002{
1003 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
1004 unsigned long count = 0; /* Number of blocks in the run */
1005 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
1006 corresponding to
1007 block_to_free */
1008 ext4_fsblk_t nr; /* Current block # */
1009 __le32 *p; /* Pointer into inode/ind
1010 for current block */
1011 int err = 0;
1012
1013 if (this_bh) { /* For indirect block */
1014 BUFFER_TRACE(this_bh, "get_write_access");
1015 err = ext4_journal_get_write_access(handle, this_bh);
1016 /* Important: if we can't update the indirect pointers
1017 * to the blocks, we can't free them. */
1018 if (err)
1019 return;
1020 }
1021
1022 for (p = first; p < last; p++) {
1023 nr = le32_to_cpu(*p);
1024 if (nr) {
1025 /* accumulate blocks to free if they're contiguous */
1026 if (count == 0) {
1027 block_to_free = nr;
1028 block_to_free_p = p;
1029 count = 1;
1030 } else if (nr == block_to_free + count) {
1031 count++;
1032 } else {
1033 err = ext4_clear_blocks(handle, inode, this_bh,
1034 block_to_free, count,
1035 block_to_free_p, p);
1036 if (err)
1037 break;
1038 block_to_free = nr;
1039 block_to_free_p = p;
1040 count = 1;
1041 }
1042 }
1043 }
1044
1045 if (!err && count > 0)
1046 err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
1047 count, block_to_free_p, p);
1048 if (err < 0)
1049 /* fatal error */
1050 return;
1051
1052 if (this_bh) {
1053 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
1054
1055 /*
1056 * The buffer head should have an attached journal head at this
1057 * point. However, if the data is corrupted and an indirect
1058 * block pointed to itself, it would have been detached when
1059 * the block was cleared. Check for this instead of OOPSing.
1060 */
1061 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
1062 ext4_handle_dirty_metadata(handle, inode, this_bh);
1063 else
1064 EXT4_ERROR_INODE(inode,
1065 "circular indirect block detected at "
1066 "block %llu",
1067 (unsigned long long) this_bh->b_blocknr);
1068 }
1069}
1070
1071/**
1072 * ext4_free_branches - free an array of branches
1073 * @handle: JBD handle for this transaction
1074 * @inode: inode we are dealing with
1075 * @parent_bh: the buffer_head which contains *@first and *@last
1076 * @first: array of block numbers
1077 * @last: pointer immediately past the end of array
1078 * @depth: depth of the branches to free
1079 *
1080 * We are freeing all blocks referred from these branches (numbers are
1081 * stored as little-endian 32-bit) and updating @inode->i_blocks
1082 * appropriately.
1083 */
1084static void ext4_free_branches(handle_t *handle, struct inode *inode,
1085 struct buffer_head *parent_bh,
1086 __le32 *first, __le32 *last, int depth)
1087{
1088 ext4_fsblk_t nr;
1089 __le32 *p;
1090
1091 if (ext4_handle_is_aborted(handle))
1092 return;
1093
1094 if (depth--) {
1095 struct buffer_head *bh;
1096 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1097 p = last;
1098 while (--p >= first) {
1099 nr = le32_to_cpu(*p);
1100 if (!nr)
1101 continue; /* A hole */
1102
1103 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
1104 nr, 1)) {
1105 EXT4_ERROR_INODE(inode,
1106 "invalid indirect mapped "
1107 "block %lu (level %d)",
1108 (unsigned long) nr, depth);
1109 break;
1110 }
1111
1112 /* Go read the buffer for the next level down */
1113 bh = sb_bread(inode->i_sb, nr);
1114
1115 /*
1116 * A read failure? Report error and clear slot
1117 * (should be rare).
1118 */
1119 if (!bh) {
1120 EXT4_ERROR_INODE_BLOCK(inode, nr,
1121 "Read failure");
1122 continue;
1123 }
1124
1125 /* This zaps the entire block. Bottom up. */
1126 BUFFER_TRACE(bh, "free child branches");
1127 ext4_free_branches(handle, inode, bh,
1128 (__le32 *) bh->b_data,
1129 (__le32 *) bh->b_data + addr_per_block,
1130 depth);
1131 brelse(bh);
1132
1133 /*
1134 * Everything below this this pointer has been
1135 * released. Now let this top-of-subtree go.
1136 *
1137 * We want the freeing of this indirect block to be
1138 * atomic in the journal with the updating of the
1139 * bitmap block which owns it. So make some room in
1140 * the journal.
1141 *
1142 * We zero the parent pointer *after* freeing its
1143 * pointee in the bitmaps, so if extend_transaction()
1144 * for some reason fails to put the bitmap changes and
1145 * the release into the same transaction, recovery
1146 * will merely complain about releasing a free block,
1147 * rather than leaking blocks.
1148 */
1149 if (ext4_handle_is_aborted(handle))
1150 return;
1151 if (try_to_extend_transaction(handle, inode)) {
1152 ext4_mark_inode_dirty(handle, inode);
1153 ext4_truncate_restart_trans(handle, inode,
1154 ext4_blocks_for_truncate(inode));
1155 }
1156
1157 /*
1158 * The forget flag here is critical because if
1159 * we are journaling (and not doing data
1160 * journaling), we have to make sure a revoke
1161 * record is written to prevent the journal
1162 * replay from overwriting the (former)
1163 * indirect block if it gets reallocated as a
1164 * data block. This must happen in the same
1165 * transaction where the data blocks are
1166 * actually freed.
1167 */
1168 ext4_free_blocks(handle, inode, NULL, nr, 1,
1169 EXT4_FREE_BLOCKS_METADATA|
1170 EXT4_FREE_BLOCKS_FORGET);
1171
1172 if (parent_bh) {
1173 /*
1174 * The block which we have just freed is
1175 * pointed to by an indirect block: journal it
1176 */
1177 BUFFER_TRACE(parent_bh, "get_write_access");
1178 if (!ext4_journal_get_write_access(handle,
1179 parent_bh)){
1180 *p = 0;
1181 BUFFER_TRACE(parent_bh,
1182 "call ext4_handle_dirty_metadata");
1183 ext4_handle_dirty_metadata(handle,
1184 inode,
1185 parent_bh);
1186 }
1187 }
1188 }
1189 } else {
1190 /* We have reached the bottom of the tree. */
1191 BUFFER_TRACE(parent_bh, "free data blocks");
1192 ext4_free_data(handle, inode, parent_bh, first, last);
1193 }
1194}
1195
Theodore Ts'o819c4922013-04-03 12:47:17 -04001196void ext4_ind_truncate(handle_t *handle, struct inode *inode)
Amir Goldsteindae1e522011-06-27 19:40:50 -04001197{
Amir Goldsteindae1e522011-06-27 19:40:50 -04001198 struct ext4_inode_info *ei = EXT4_I(inode);
1199 __le32 *i_data = ei->i_data;
1200 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
Amir Goldsteindae1e522011-06-27 19:40:50 -04001201 ext4_lblk_t offsets[4];
1202 Indirect chain[4];
1203 Indirect *partial;
1204 __le32 nr = 0;
1205 int n = 0;
1206 ext4_lblk_t last_block, max_block;
1207 unsigned blocksize = inode->i_sb->s_blocksize;
Amir Goldsteindae1e522011-06-27 19:40:50 -04001208
1209 last_block = (inode->i_size + blocksize-1)
1210 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
1211 max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
1212 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
1213
Amir Goldsteindae1e522011-06-27 19:40:50 -04001214 if (last_block != max_block) {
1215 n = ext4_block_to_path(inode, last_block, offsets, NULL);
1216 if (n == 0)
Theodore Ts'o819c4922013-04-03 12:47:17 -04001217 return;
Amir Goldsteindae1e522011-06-27 19:40:50 -04001218 }
1219
Zheng Liu51865fd2012-11-08 21:57:32 -05001220 ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
Amir Goldsteindae1e522011-06-27 19:40:50 -04001221
1222 /*
1223 * The orphan list entry will now protect us from any crash which
1224 * occurs before the truncate completes, so it is now safe to propagate
1225 * the new, shorter inode size (held for now in i_size) into the
1226 * on-disk inode. We do this via i_disksize, which is the value which
1227 * ext4 *really* writes onto the disk inode.
1228 */
1229 ei->i_disksize = inode->i_size;
1230
1231 if (last_block == max_block) {
1232 /*
1233 * It is unnecessary to free any data blocks if last_block is
1234 * equal to the indirect block limit.
1235 */
Theodore Ts'o819c4922013-04-03 12:47:17 -04001236 return;
Amir Goldsteindae1e522011-06-27 19:40:50 -04001237 } else if (n == 1) { /* direct blocks */
1238 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
1239 i_data + EXT4_NDIR_BLOCKS);
1240 goto do_indirects;
1241 }
1242
1243 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
1244 /* Kill the top of shared branch (not detached) */
1245 if (nr) {
1246 if (partial == chain) {
1247 /* Shared branch grows from the inode */
1248 ext4_free_branches(handle, inode, NULL,
1249 &nr, &nr+1, (chain+n-1) - partial);
1250 *partial->p = 0;
1251 /*
1252 * We mark the inode dirty prior to restart,
1253 * and prior to stop. No need for it here.
1254 */
1255 } else {
1256 /* Shared branch grows from an indirect block */
1257 BUFFER_TRACE(partial->bh, "get_write_access");
1258 ext4_free_branches(handle, inode, partial->bh,
1259 partial->p,
1260 partial->p+1, (chain+n-1) - partial);
1261 }
1262 }
1263 /* Clear the ends of indirect blocks on the shared branch */
1264 while (partial > chain) {
1265 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
1266 (__le32*)partial->bh->b_data+addr_per_block,
1267 (chain+n-1) - partial);
1268 BUFFER_TRACE(partial->bh, "call brelse");
1269 brelse(partial->bh);
1270 partial--;
1271 }
1272do_indirects:
1273 /* Kill the remaining (whole) subtrees */
1274 switch (offsets[0]) {
1275 default:
1276 nr = i_data[EXT4_IND_BLOCK];
1277 if (nr) {
1278 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
1279 i_data[EXT4_IND_BLOCK] = 0;
1280 }
1281 case EXT4_IND_BLOCK:
1282 nr = i_data[EXT4_DIND_BLOCK];
1283 if (nr) {
1284 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
1285 i_data[EXT4_DIND_BLOCK] = 0;
1286 }
1287 case EXT4_DIND_BLOCK:
1288 nr = i_data[EXT4_TIND_BLOCK];
1289 if (nr) {
1290 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
1291 i_data[EXT4_TIND_BLOCK] = 0;
1292 }
1293 case EXT4_TIND_BLOCK:
1294 ;
1295 }
Amir Goldsteindae1e522011-06-27 19:40:50 -04001296}
1297
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001298/**
1299 * ext4_ind_remove_space - remove space from the range
1300 * @handle: JBD handle for this transaction
1301 * @inode: inode we are dealing with
1302 * @start: First block to remove
1303 * @end: One block after the last block to remove (exclusive)
1304 *
1305 * Free the blocks in the defined range (end is exclusive endpoint of
1306 * range). This is used by ext4_punch_hole().
1307 */
1308int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
1309 ext4_lblk_t start, ext4_lblk_t end)
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001310{
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001311 struct ext4_inode_info *ei = EXT4_I(inode);
1312 __le32 *i_data = ei->i_data;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001313 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001314 ext4_lblk_t offsets[4], offsets2[4];
1315 Indirect chain[4], chain2[4];
1316 Indirect *partial, *partial2;
1317 ext4_lblk_t max_block;
1318 __le32 nr = 0, nr2 = 0;
1319 int n = 0, n2 = 0;
1320 unsigned blocksize = inode->i_sb->s_blocksize;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001321
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001322 max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
1323 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
1324 if (end >= max_block)
1325 end = max_block;
1326 if ((start >= end) || (start > max_block))
1327 return 0;
Jan Karaa93cd4c2014-06-26 12:30:54 -04001328
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001329 n = ext4_block_to_path(inode, start, offsets, NULL);
1330 n2 = ext4_block_to_path(inode, end, offsets2, NULL);
1331
1332 BUG_ON(n > n2);
1333
1334 if ((n == 1) && (n == n2)) {
1335 /* We're punching only within direct block range */
1336 ext4_free_data(handle, inode, NULL, i_data + offsets[0],
1337 i_data + offsets2[0]);
1338 return 0;
1339 } else if (n2 > n) {
1340 /*
1341 * Start and end are on a different levels so we're going to
1342 * free partial block at start, and partial block at end of
1343 * the range. If there are some levels in between then
1344 * do_indirects label will take care of that.
1345 */
1346
1347 if (n == 1) {
1348 /*
1349 * Start is at the direct block level, free
1350 * everything to the end of the level.
1351 */
1352 ext4_free_data(handle, inode, NULL, i_data + offsets[0],
1353 i_data + EXT4_NDIR_BLOCKS);
1354 goto end_range;
1355 }
1356
1357
1358 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
1359 if (nr) {
1360 if (partial == chain) {
1361 /* Shared branch grows from the inode */
1362 ext4_free_branches(handle, inode, NULL,
1363 &nr, &nr+1, (chain+n-1) - partial);
1364 *partial->p = 0;
Jan Karaa93cd4c2014-06-26 12:30:54 -04001365 } else {
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001366 /* Shared branch grows from an indirect block */
1367 BUFFER_TRACE(partial->bh, "get_write_access");
1368 ext4_free_branches(handle, inode, partial->bh,
1369 partial->p,
1370 partial->p+1, (chain+n-1) - partial);
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001371 }
1372 }
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001373
1374 /*
1375 * Clear the ends of indirect blocks on the shared branch
1376 * at the start of the range
1377 */
1378 while (partial > chain) {
1379 ext4_free_branches(handle, inode, partial->bh,
1380 partial->p + 1,
1381 (__le32 *)partial->bh->b_data+addr_per_block,
1382 (chain+n-1) - partial);
1383 BUFFER_TRACE(partial->bh, "call brelse");
1384 brelse(partial->bh);
1385 partial--;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001386 }
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001387
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001388end_range:
1389 partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
1390 if (nr2) {
1391 if (partial2 == chain2) {
1392 /*
1393 * Remember, end is exclusive so here we're at
1394 * the start of the next level we're not going
1395 * to free. Everything was covered by the start
1396 * of the range.
1397 */
1398 return 0;
1399 } else {
1400 /* Shared branch grows from an indirect block */
1401 partial2--;
1402 }
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001403 } else {
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001404 /*
1405 * ext4_find_shared returns Indirect structure which
1406 * points to the last element which should not be
1407 * removed by truncate. But this is end of the range
1408 * in punch_hole so we need to point to the next element
1409 */
1410 partial2->p++;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001411 }
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001412
1413 /*
1414 * Clear the ends of indirect blocks on the shared branch
1415 * at the end of the range
1416 */
1417 while (partial2 > chain2) {
1418 ext4_free_branches(handle, inode, partial2->bh,
1419 (__le32 *)partial2->bh->b_data,
1420 partial2->p,
1421 (chain2+n2-1) - partial2);
1422 BUFFER_TRACE(partial2->bh, "call brelse");
1423 brelse(partial2->bh);
1424 partial2--;
1425 }
1426 goto do_indirects;
1427 }
1428
1429 /* Punch happened within the same level (n == n2) */
1430 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
1431 partial2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
1432 /*
1433 * ext4_find_shared returns Indirect structure which
1434 * points to the last element which should not be
1435 * removed by truncate. But this is end of the range
1436 * in punch_hole so we need to point to the next element
1437 */
1438 partial2->p++;
1439 while ((partial > chain) || (partial2 > chain2)) {
1440 /* We're at the same block, so we're almost finished */
1441 if ((partial->bh && partial2->bh) &&
1442 (partial->bh->b_blocknr == partial2->bh->b_blocknr)) {
1443 if ((partial > chain) && (partial2 > chain2)) {
1444 ext4_free_branches(handle, inode, partial->bh,
1445 partial->p + 1,
1446 partial2->p,
1447 (chain+n-1) - partial);
1448 BUFFER_TRACE(partial->bh, "call brelse");
1449 brelse(partial->bh);
1450 BUFFER_TRACE(partial2->bh, "call brelse");
1451 brelse(partial2->bh);
1452 }
1453 return 0;
1454 }
1455 /*
1456 * Clear the ends of indirect blocks on the shared branch
1457 * at the start of the range
1458 */
1459 if (partial > chain) {
1460 ext4_free_branches(handle, inode, partial->bh,
1461 partial->p + 1,
1462 (__le32 *)partial->bh->b_data+addr_per_block,
1463 (chain+n-1) - partial);
1464 BUFFER_TRACE(partial->bh, "call brelse");
1465 brelse(partial->bh);
1466 partial--;
1467 }
1468 /*
1469 * Clear the ends of indirect blocks on the shared branch
1470 * at the end of the range
1471 */
1472 if (partial2 > chain2) {
1473 ext4_free_branches(handle, inode, partial2->bh,
1474 (__le32 *)partial2->bh->b_data,
1475 partial2->p,
1476 (chain2+n-1) - partial2);
1477 BUFFER_TRACE(partial2->bh, "call brelse");
1478 brelse(partial2->bh);
1479 partial2--;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001480 }
1481 }
1482
Lukas Czerner4f579ae2014-07-15 06:03:38 -04001483do_indirects:
1484 /* Kill the remaining (whole) subtrees */
1485 switch (offsets[0]) {
1486 default:
1487 if (++n >= n2)
1488 return 0;
1489 nr = i_data[EXT4_IND_BLOCK];
1490 if (nr) {
1491 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
1492 i_data[EXT4_IND_BLOCK] = 0;
1493 }
1494 case EXT4_IND_BLOCK:
1495 if (++n >= n2)
1496 return 0;
1497 nr = i_data[EXT4_DIND_BLOCK];
1498 if (nr) {
1499 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
1500 i_data[EXT4_DIND_BLOCK] = 0;
1501 }
1502 case EXT4_DIND_BLOCK:
1503 if (++n >= n2)
1504 return 0;
1505 nr = i_data[EXT4_TIND_BLOCK];
1506 if (nr) {
1507 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
1508 i_data[EXT4_TIND_BLOCK] = 0;
1509 }
1510 case EXT4_TIND_BLOCK:
1511 ;
1512 }
1513 return 0;
Zheng Liu8bad6fc2013-01-28 09:21:37 -05001514}