Commit | Line | Data |
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dae1e52c AG |
1 | /* |
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 | ||
dae1e52c AG |
23 | #include "ext4_jbd2.h" |
24 | #include "truncate.h" | |
4a092d73 | 25 | #include "ext4_extents.h" /* Needed for EXT_MAX_BLOCKS */ |
dae1e52c AG |
26 | |
27 | #include <trace/events/ext4.h> | |
28 | ||
29 | typedef struct { | |
30 | __le32 *p; | |
31 | __le32 key; | |
32 | struct buffer_head *bh; | |
33 | } Indirect; | |
34 | ||
35 | static 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 | ||
72 | static 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 | */ | |
142 | static 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; | |
860d21e2 | 149 | int ret = -EIO; |
dae1e52c AG |
150 | |
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)); | |
860d21e2 TT |
158 | if (unlikely(!bh)) { |
159 | ret = -ENOMEM; | |
dae1e52c | 160 | goto failure; |
860d21e2 | 161 | } |
dae1e52c AG |
162 | |
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 | ||
182 | failure: | |
860d21e2 | 183 | *err = ret; |
dae1e52c AG |
184 | no_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 | */ | |
208 | static 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; | |
dae1e52c AG |
213 | |
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 | */ | |
f86186b4 | 228 | return ext4_inode_to_goal_block(inode); |
dae1e52c AG |
229 | } |
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 | */ | |
242 | static 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 | */ | |
268 | static 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 | /** | |
295 | * ext4_alloc_blocks: multiple allocate blocks needed for a branch | |
296 | * @handle: handle for this transaction | |
297 | * @inode: inode which needs allocated blocks | |
298 | * @iblock: the logical block to start allocated at | |
299 | * @goal: preferred physical block of allocation | |
300 | * @indirect_blks: the number of blocks need to allocate for indirect | |
301 | * blocks | |
302 | * @blks: number of desired blocks | |
303 | * @new_blocks: on return it will store the new block numbers for | |
304 | * the indirect blocks(if needed) and the first direct block, | |
305 | * @err: on return it will store the error code | |
306 | * | |
307 | * This function will return the number of blocks allocated as | |
308 | * requested by the passed-in parameters. | |
309 | */ | |
310 | static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, | |
311 | ext4_lblk_t iblock, ext4_fsblk_t goal, | |
312 | int indirect_blks, int blks, | |
313 | ext4_fsblk_t new_blocks[4], int *err) | |
314 | { | |
315 | struct ext4_allocation_request ar; | |
316 | int target, i; | |
317 | unsigned long count = 0, blk_allocated = 0; | |
318 | int index = 0; | |
319 | ext4_fsblk_t current_block = 0; | |
320 | int ret = 0; | |
321 | ||
322 | /* | |
323 | * Here we try to allocate the requested multiple blocks at once, | |
324 | * on a best-effort basis. | |
325 | * To build a branch, we should allocate blocks for | |
326 | * the indirect blocks(if not allocated yet), and at least | |
327 | * the first direct block of this branch. That's the | |
328 | * minimum number of blocks need to allocate(required) | |
329 | */ | |
330 | /* first we try to allocate the indirect blocks */ | |
331 | target = indirect_blks; | |
332 | while (target > 0) { | |
333 | count = target; | |
334 | /* allocating blocks for indirect blocks and direct blocks */ | |
335 | current_block = ext4_new_meta_blocks(handle, inode, goal, | |
336 | 0, &count, err); | |
337 | if (*err) | |
338 | goto failed_out; | |
339 | ||
340 | if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) { | |
341 | EXT4_ERROR_INODE(inode, | |
342 | "current_block %llu + count %lu > %d!", | |
343 | current_block, count, | |
344 | EXT4_MAX_BLOCK_FILE_PHYS); | |
345 | *err = -EIO; | |
346 | goto failed_out; | |
347 | } | |
348 | ||
349 | target -= count; | |
350 | /* allocate blocks for indirect blocks */ | |
351 | while (index < indirect_blks && count) { | |
352 | new_blocks[index++] = current_block++; | |
353 | count--; | |
354 | } | |
355 | if (count > 0) { | |
356 | /* | |
357 | * save the new block number | |
358 | * for the first direct block | |
359 | */ | |
360 | new_blocks[index] = current_block; | |
361 | printk(KERN_INFO "%s returned more blocks than " | |
362 | "requested\n", __func__); | |
363 | WARN_ON(1); | |
364 | break; | |
365 | } | |
366 | } | |
367 | ||
368 | target = blks - count ; | |
369 | blk_allocated = count; | |
370 | if (!target) | |
371 | goto allocated; | |
372 | /* Now allocate data blocks */ | |
373 | memset(&ar, 0, sizeof(ar)); | |
374 | ar.inode = inode; | |
375 | ar.goal = goal; | |
376 | ar.len = target; | |
377 | ar.logical = iblock; | |
378 | if (S_ISREG(inode->i_mode)) | |
379 | /* enable in-core preallocation only for regular files */ | |
380 | ar.flags = EXT4_MB_HINT_DATA; | |
381 | ||
382 | current_block = ext4_mb_new_blocks(handle, &ar, err); | |
383 | if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) { | |
384 | EXT4_ERROR_INODE(inode, | |
385 | "current_block %llu + ar.len %d > %d!", | |
386 | current_block, ar.len, | |
387 | EXT4_MAX_BLOCK_FILE_PHYS); | |
388 | *err = -EIO; | |
389 | goto failed_out; | |
390 | } | |
391 | ||
392 | if (*err && (target == blks)) { | |
393 | /* | |
394 | * if the allocation failed and we didn't allocate | |
395 | * any blocks before | |
396 | */ | |
397 | goto failed_out; | |
398 | } | |
399 | if (!*err) { | |
400 | if (target == blks) { | |
401 | /* | |
402 | * save the new block number | |
403 | * for the first direct block | |
404 | */ | |
405 | new_blocks[index] = current_block; | |
406 | } | |
407 | blk_allocated += ar.len; | |
408 | } | |
409 | allocated: | |
410 | /* total number of blocks allocated for direct blocks */ | |
411 | ret = blk_allocated; | |
412 | *err = 0; | |
413 | return ret; | |
414 | failed_out: | |
415 | for (i = 0; i < index; i++) | |
416 | ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0); | |
417 | return ret; | |
418 | } | |
419 | ||
420 | /** | |
421 | * ext4_alloc_branch - allocate and set up a chain of blocks. | |
422 | * @handle: handle for this transaction | |
423 | * @inode: owner | |
424 | * @indirect_blks: number of allocated indirect blocks | |
425 | * @blks: number of allocated direct blocks | |
426 | * @goal: preferred place for allocation | |
427 | * @offsets: offsets (in the blocks) to store the pointers to next. | |
428 | * @branch: place to store the chain in. | |
429 | * | |
430 | * This function allocates blocks, zeroes out all but the last one, | |
431 | * links them into chain and (if we are synchronous) writes them to disk. | |
432 | * In other words, it prepares a branch that can be spliced onto the | |
433 | * inode. It stores the information about that chain in the branch[], in | |
434 | * the same format as ext4_get_branch() would do. We are calling it after | |
435 | * we had read the existing part of chain and partial points to the last | |
436 | * triple of that (one with zero ->key). Upon the exit we have the same | |
437 | * picture as after the successful ext4_get_block(), except that in one | |
438 | * place chain is disconnected - *branch->p is still zero (we did not | |
439 | * set the last link), but branch->key contains the number that should | |
440 | * be placed into *branch->p to fill that gap. | |
441 | * | |
442 | * If allocation fails we free all blocks we've allocated (and forget | |
443 | * their buffer_heads) and return the error value the from failed | |
444 | * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain | |
445 | * as described above and return 0. | |
446 | */ | |
447 | static int ext4_alloc_branch(handle_t *handle, struct inode *inode, | |
448 | ext4_lblk_t iblock, int indirect_blks, | |
449 | int *blks, ext4_fsblk_t goal, | |
450 | ext4_lblk_t *offsets, Indirect *branch) | |
451 | { | |
452 | int blocksize = inode->i_sb->s_blocksize; | |
453 | int i, n = 0; | |
454 | int err = 0; | |
455 | struct buffer_head *bh; | |
456 | int num; | |
457 | ext4_fsblk_t new_blocks[4]; | |
458 | ext4_fsblk_t current_block; | |
459 | ||
460 | num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks, | |
461 | *blks, new_blocks, &err); | |
462 | if (err) | |
463 | return err; | |
464 | ||
465 | branch[0].key = cpu_to_le32(new_blocks[0]); | |
466 | /* | |
467 | * metadata blocks and data blocks are allocated. | |
468 | */ | |
469 | for (n = 1; n <= indirect_blks; n++) { | |
470 | /* | |
471 | * Get buffer_head for parent block, zero it out | |
472 | * and set the pointer to new one, then send | |
473 | * parent to disk. | |
474 | */ | |
475 | bh = sb_getblk(inode->i_sb, new_blocks[n-1]); | |
476 | if (unlikely(!bh)) { | |
860d21e2 | 477 | err = -ENOMEM; |
dae1e52c AG |
478 | goto failed; |
479 | } | |
480 | ||
481 | branch[n].bh = bh; | |
482 | lock_buffer(bh); | |
483 | BUFFER_TRACE(bh, "call get_create_access"); | |
484 | err = ext4_journal_get_create_access(handle, bh); | |
485 | if (err) { | |
486 | /* Don't brelse(bh) here; it's done in | |
487 | * ext4_journal_forget() below */ | |
488 | unlock_buffer(bh); | |
489 | goto failed; | |
490 | } | |
491 | ||
492 | memset(bh->b_data, 0, blocksize); | |
493 | branch[n].p = (__le32 *) bh->b_data + offsets[n]; | |
494 | branch[n].key = cpu_to_le32(new_blocks[n]); | |
495 | *branch[n].p = branch[n].key; | |
496 | if (n == indirect_blks) { | |
497 | current_block = new_blocks[n]; | |
498 | /* | |
499 | * End of chain, update the last new metablock of | |
500 | * the chain to point to the new allocated | |
501 | * data blocks numbers | |
502 | */ | |
503 | for (i = 1; i < num; i++) | |
504 | *(branch[n].p + i) = cpu_to_le32(++current_block); | |
505 | } | |
506 | BUFFER_TRACE(bh, "marking uptodate"); | |
507 | set_buffer_uptodate(bh); | |
508 | unlock_buffer(bh); | |
509 | ||
510 | BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); | |
511 | err = ext4_handle_dirty_metadata(handle, inode, bh); | |
512 | if (err) | |
513 | goto failed; | |
514 | } | |
515 | *blks = num; | |
516 | return err; | |
517 | failed: | |
518 | /* Allocation failed, free what we already allocated */ | |
519 | ext4_free_blocks(handle, inode, NULL, new_blocks[0], 1, 0); | |
520 | for (i = 1; i <= n ; i++) { | |
521 | /* | |
522 | * branch[i].bh is newly allocated, so there is no | |
523 | * need to revoke the block, which is why we don't | |
524 | * need to set EXT4_FREE_BLOCKS_METADATA. | |
525 | */ | |
526 | ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, | |
527 | EXT4_FREE_BLOCKS_FORGET); | |
528 | } | |
529 | for (i = n+1; i < indirect_blks; i++) | |
530 | ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0); | |
531 | ||
532 | ext4_free_blocks(handle, inode, NULL, new_blocks[i], num, 0); | |
533 | ||
534 | return err; | |
535 | } | |
536 | ||
537 | /** | |
538 | * ext4_splice_branch - splice the allocated branch onto inode. | |
539 | * @handle: handle for this transaction | |
540 | * @inode: owner | |
541 | * @block: (logical) number of block we are adding | |
542 | * @chain: chain of indirect blocks (with a missing link - see | |
543 | * ext4_alloc_branch) | |
544 | * @where: location of missing link | |
545 | * @num: number of indirect blocks we are adding | |
546 | * @blks: number of direct blocks we are adding | |
547 | * | |
548 | * This function fills the missing link and does all housekeeping needed in | |
549 | * inode (->i_blocks, etc.). In case of success we end up with the full | |
550 | * chain to new block and return 0. | |
551 | */ | |
552 | static int ext4_splice_branch(handle_t *handle, struct inode *inode, | |
553 | ext4_lblk_t block, Indirect *where, int num, | |
554 | int blks) | |
555 | { | |
556 | int i; | |
557 | int err = 0; | |
558 | ext4_fsblk_t current_block; | |
559 | ||
560 | /* | |
561 | * If we're splicing into a [td]indirect block (as opposed to the | |
562 | * inode) then we need to get write access to the [td]indirect block | |
563 | * before the splice. | |
564 | */ | |
565 | if (where->bh) { | |
566 | BUFFER_TRACE(where->bh, "get_write_access"); | |
567 | err = ext4_journal_get_write_access(handle, where->bh); | |
568 | if (err) | |
569 | goto err_out; | |
570 | } | |
571 | /* That's it */ | |
572 | ||
573 | *where->p = where->key; | |
574 | ||
575 | /* | |
576 | * Update the host buffer_head or inode to point to more just allocated | |
577 | * direct blocks blocks | |
578 | */ | |
579 | if (num == 0 && blks > 1) { | |
580 | current_block = le32_to_cpu(where->key) + 1; | |
581 | for (i = 1; i < blks; i++) | |
582 | *(where->p + i) = cpu_to_le32(current_block++); | |
583 | } | |
584 | ||
585 | /* We are done with atomic stuff, now do the rest of housekeeping */ | |
586 | /* had we spliced it onto indirect block? */ | |
587 | if (where->bh) { | |
588 | /* | |
589 | * If we spliced it onto an indirect block, we haven't | |
590 | * altered the inode. Note however that if it is being spliced | |
591 | * onto an indirect block at the very end of the file (the | |
592 | * file is growing) then we *will* alter the inode to reflect | |
593 | * the new i_size. But that is not done here - it is done in | |
594 | * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode. | |
595 | */ | |
596 | jbd_debug(5, "splicing indirect only\n"); | |
597 | BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata"); | |
598 | err = ext4_handle_dirty_metadata(handle, inode, where->bh); | |
599 | if (err) | |
600 | goto err_out; | |
601 | } else { | |
602 | /* | |
603 | * OK, we spliced it into the inode itself on a direct block. | |
604 | */ | |
605 | ext4_mark_inode_dirty(handle, inode); | |
606 | jbd_debug(5, "splicing direct\n"); | |
607 | } | |
608 | return err; | |
609 | ||
610 | err_out: | |
611 | for (i = 1; i <= num; i++) { | |
612 | /* | |
613 | * branch[i].bh is newly allocated, so there is no | |
614 | * need to revoke the block, which is why we don't | |
615 | * need to set EXT4_FREE_BLOCKS_METADATA. | |
616 | */ | |
617 | ext4_free_blocks(handle, inode, where[i].bh, 0, 1, | |
618 | EXT4_FREE_BLOCKS_FORGET); | |
619 | } | |
620 | ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key), | |
621 | blks, 0); | |
622 | ||
623 | return err; | |
624 | } | |
625 | ||
626 | /* | |
627 | * The ext4_ind_map_blocks() function handles non-extents inodes | |
628 | * (i.e., using the traditional indirect/double-indirect i_blocks | |
629 | * scheme) for ext4_map_blocks(). | |
630 | * | |
631 | * Allocation strategy is simple: if we have to allocate something, we will | |
632 | * have to go the whole way to leaf. So let's do it before attaching anything | |
633 | * to tree, set linkage between the newborn blocks, write them if sync is | |
634 | * required, recheck the path, free and repeat if check fails, otherwise | |
635 | * set the last missing link (that will protect us from any truncate-generated | |
636 | * removals - all blocks on the path are immune now) and possibly force the | |
637 | * write on the parent block. | |
638 | * That has a nice additional property: no special recovery from the failed | |
639 | * allocations is needed - we simply release blocks and do not touch anything | |
640 | * reachable from inode. | |
641 | * | |
642 | * `handle' can be NULL if create == 0. | |
643 | * | |
644 | * return > 0, # of blocks mapped or allocated. | |
645 | * return = 0, if plain lookup failed. | |
646 | * return < 0, error case. | |
647 | * | |
648 | * The ext4_ind_get_blocks() function should be called with | |
649 | * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem | |
650 | * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or | |
651 | * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system | |
652 | * blocks. | |
653 | */ | |
654 | int ext4_ind_map_blocks(handle_t *handle, struct inode *inode, | |
655 | struct ext4_map_blocks *map, | |
656 | int flags) | |
657 | { | |
658 | int err = -EIO; | |
659 | ext4_lblk_t offsets[4]; | |
660 | Indirect chain[4]; | |
661 | Indirect *partial; | |
662 | ext4_fsblk_t goal; | |
663 | int indirect_blks; | |
664 | int blocks_to_boundary = 0; | |
665 | int depth; | |
666 | int count = 0; | |
667 | ext4_fsblk_t first_block = 0; | |
668 | ||
669 | trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); | |
670 | J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))); | |
671 | J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0); | |
672 | depth = ext4_block_to_path(inode, map->m_lblk, offsets, | |
673 | &blocks_to_boundary); | |
674 | ||
675 | if (depth == 0) | |
676 | goto out; | |
677 | ||
678 | partial = ext4_get_branch(inode, depth, offsets, chain, &err); | |
679 | ||
680 | /* Simplest case - block found, no allocation needed */ | |
681 | if (!partial) { | |
682 | first_block = le32_to_cpu(chain[depth - 1].key); | |
683 | count++; | |
684 | /*map more blocks*/ | |
685 | while (count < map->m_len && count <= blocks_to_boundary) { | |
686 | ext4_fsblk_t blk; | |
687 | ||
688 | blk = le32_to_cpu(*(chain[depth-1].p + count)); | |
689 | ||
690 | if (blk == first_block + count) | |
691 | count++; | |
692 | else | |
693 | break; | |
694 | } | |
695 | goto got_it; | |
696 | } | |
697 | ||
698 | /* Next simple case - plain lookup or failed read of indirect block */ | |
699 | if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO) | |
700 | goto cleanup; | |
701 | ||
702 | /* | |
703 | * Okay, we need to do block allocation. | |
704 | */ | |
bab08ab9 TT |
705 | if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, |
706 | EXT4_FEATURE_RO_COMPAT_BIGALLOC)) { | |
707 | EXT4_ERROR_INODE(inode, "Can't allocate blocks for " | |
708 | "non-extent mapped inodes with bigalloc"); | |
709 | return -ENOSPC; | |
710 | } | |
711 | ||
dae1e52c AG |
712 | goal = ext4_find_goal(inode, map->m_lblk, partial); |
713 | ||
714 | /* the number of blocks need to allocate for [d,t]indirect blocks */ | |
715 | indirect_blks = (chain + depth) - partial - 1; | |
716 | ||
717 | /* | |
718 | * Next look up the indirect map to count the totoal number of | |
719 | * direct blocks to allocate for this branch. | |
720 | */ | |
721 | count = ext4_blks_to_allocate(partial, indirect_blks, | |
722 | map->m_len, blocks_to_boundary); | |
723 | /* | |
724 | * Block out ext4_truncate while we alter the tree | |
725 | */ | |
726 | err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks, | |
727 | &count, goal, | |
728 | offsets + (partial - chain), partial); | |
729 | ||
730 | /* | |
731 | * The ext4_splice_branch call will free and forget any buffers | |
732 | * on the new chain if there is a failure, but that risks using | |
733 | * up transaction credits, especially for bitmaps where the | |
734 | * credits cannot be returned. Can we handle this somehow? We | |
735 | * may need to return -EAGAIN upwards in the worst case. --sct | |
736 | */ | |
737 | if (!err) | |
738 | err = ext4_splice_branch(handle, inode, map->m_lblk, | |
739 | partial, indirect_blks, count); | |
740 | if (err) | |
741 | goto cleanup; | |
742 | ||
743 | map->m_flags |= EXT4_MAP_NEW; | |
744 | ||
745 | ext4_update_inode_fsync_trans(handle, inode, 1); | |
746 | got_it: | |
747 | map->m_flags |= EXT4_MAP_MAPPED; | |
748 | map->m_pblk = le32_to_cpu(chain[depth-1].key); | |
749 | map->m_len = count; | |
750 | if (count > blocks_to_boundary) | |
751 | map->m_flags |= EXT4_MAP_BOUNDARY; | |
752 | err = count; | |
753 | /* Clean up and exit */ | |
754 | partial = chain + depth - 1; /* the whole chain */ | |
755 | cleanup: | |
756 | while (partial > chain) { | |
757 | BUFFER_TRACE(partial->bh, "call brelse"); | |
758 | brelse(partial->bh); | |
759 | partial--; | |
760 | } | |
761 | out: | |
19b303d8 | 762 | trace_ext4_ind_map_blocks_exit(inode, map, err); |
dae1e52c AG |
763 | return err; |
764 | } | |
765 | ||
766 | /* | |
767 | * O_DIRECT for ext3 (or indirect map) based files | |
768 | * | |
769 | * If the O_DIRECT write will extend the file then add this inode to the | |
770 | * orphan list. So recovery will truncate it back to the original size | |
771 | * if the machine crashes during the write. | |
772 | * | |
773 | * If the O_DIRECT write is intantiating holes inside i_size and the machine | |
774 | * crashes then stale disk data _may_ be exposed inside the file. But current | |
775 | * VFS code falls back into buffered path in that case so we are safe. | |
776 | */ | |
777 | ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb, | |
778 | const struct iovec *iov, loff_t offset, | |
779 | unsigned long nr_segs) | |
780 | { | |
781 | struct file *file = iocb->ki_filp; | |
782 | struct inode *inode = file->f_mapping->host; | |
783 | struct ext4_inode_info *ei = EXT4_I(inode); | |
784 | handle_t *handle; | |
785 | ssize_t ret; | |
786 | int orphan = 0; | |
787 | size_t count = iov_length(iov, nr_segs); | |
788 | int retries = 0; | |
789 | ||
790 | if (rw == WRITE) { | |
791 | loff_t final_size = offset + count; | |
792 | ||
793 | if (final_size > inode->i_size) { | |
794 | /* Credits for sb + inode write */ | |
795 | handle = ext4_journal_start(inode, 2); | |
796 | if (IS_ERR(handle)) { | |
797 | ret = PTR_ERR(handle); | |
798 | goto out; | |
799 | } | |
800 | ret = ext4_orphan_add(handle, inode); | |
801 | if (ret) { | |
802 | ext4_journal_stop(handle); | |
803 | goto out; | |
804 | } | |
805 | orphan = 1; | |
806 | ei->i_disksize = inode->i_size; | |
807 | ext4_journal_stop(handle); | |
808 | } | |
809 | } | |
810 | ||
811 | retry: | |
dccaf33f | 812 | if (rw == READ && ext4_should_dioread_nolock(inode)) { |
c278531d DM |
813 | if (unlikely(atomic_read(&EXT4_I(inode)->i_unwritten))) { |
814 | mutex_lock(&inode->i_mutex); | |
815 | ext4_flush_unwritten_io(inode); | |
816 | mutex_unlock(&inode->i_mutex); | |
817 | } | |
17335dcc DM |
818 | /* |
819 | * Nolock dioread optimization may be dynamically disabled | |
820 | * via ext4_inode_block_unlocked_dio(). Check inode's state | |
821 | * while holding extra i_dio_count ref. | |
822 | */ | |
823 | atomic_inc(&inode->i_dio_count); | |
824 | smp_mb(); | |
825 | if (unlikely(ext4_test_inode_state(inode, | |
826 | EXT4_STATE_DIOREAD_LOCK))) { | |
827 | inode_dio_done(inode); | |
828 | goto locked; | |
829 | } | |
dae1e52c AG |
830 | ret = __blockdev_direct_IO(rw, iocb, inode, |
831 | inode->i_sb->s_bdev, iov, | |
832 | offset, nr_segs, | |
833 | ext4_get_block, NULL, NULL, 0); | |
17335dcc | 834 | inode_dio_done(inode); |
dccaf33f | 835 | } else { |
17335dcc | 836 | locked: |
60ad4466 LT |
837 | ret = blockdev_direct_IO(rw, iocb, inode, iov, |
838 | offset, nr_segs, ext4_get_block); | |
dae1e52c AG |
839 | |
840 | if (unlikely((rw & WRITE) && ret < 0)) { | |
841 | loff_t isize = i_size_read(inode); | |
842 | loff_t end = offset + iov_length(iov, nr_segs); | |
843 | ||
844 | if (end > isize) | |
845 | ext4_truncate_failed_write(inode); | |
846 | } | |
847 | } | |
848 | if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) | |
849 | goto retry; | |
850 | ||
851 | if (orphan) { | |
852 | int err; | |
853 | ||
854 | /* Credits for sb + inode write */ | |
855 | handle = ext4_journal_start(inode, 2); | |
856 | if (IS_ERR(handle)) { | |
857 | /* This is really bad luck. We've written the data | |
858 | * but cannot extend i_size. Bail out and pretend | |
859 | * the write failed... */ | |
860 | ret = PTR_ERR(handle); | |
861 | if (inode->i_nlink) | |
862 | ext4_orphan_del(NULL, inode); | |
863 | ||
864 | goto out; | |
865 | } | |
866 | if (inode->i_nlink) | |
867 | ext4_orphan_del(handle, inode); | |
868 | if (ret > 0) { | |
869 | loff_t end = offset + ret; | |
870 | if (end > inode->i_size) { | |
871 | ei->i_disksize = end; | |
872 | i_size_write(inode, end); | |
873 | /* | |
874 | * We're going to return a positive `ret' | |
875 | * here due to non-zero-length I/O, so there's | |
876 | * no way of reporting error returns from | |
877 | * ext4_mark_inode_dirty() to userspace. So | |
878 | * ignore it. | |
879 | */ | |
880 | ext4_mark_inode_dirty(handle, inode); | |
881 | } | |
882 | } | |
883 | err = ext4_journal_stop(handle); | |
884 | if (ret == 0) | |
885 | ret = err; | |
886 | } | |
887 | out: | |
888 | return ret; | |
889 | } | |
890 | ||
891 | /* | |
892 | * Calculate the number of metadata blocks need to reserve | |
893 | * to allocate a new block at @lblocks for non extent file based file | |
894 | */ | |
895 | int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock) | |
896 | { | |
897 | struct ext4_inode_info *ei = EXT4_I(inode); | |
898 | sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1); | |
899 | int blk_bits; | |
900 | ||
901 | if (lblock < EXT4_NDIR_BLOCKS) | |
902 | return 0; | |
903 | ||
904 | lblock -= EXT4_NDIR_BLOCKS; | |
905 | ||
906 | if (ei->i_da_metadata_calc_len && | |
907 | (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) { | |
908 | ei->i_da_metadata_calc_len++; | |
909 | return 0; | |
910 | } | |
911 | ei->i_da_metadata_calc_last_lblock = lblock & dind_mask; | |
912 | ei->i_da_metadata_calc_len = 1; | |
913 | blk_bits = order_base_2(lblock); | |
914 | return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1; | |
915 | } | |
916 | ||
917 | int ext4_ind_trans_blocks(struct inode *inode, int nrblocks, int chunk) | |
918 | { | |
919 | int indirects; | |
920 | ||
921 | /* if nrblocks are contiguous */ | |
922 | if (chunk) { | |
923 | /* | |
924 | * With N contiguous data blocks, we need at most | |
925 | * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks, | |
926 | * 2 dindirect blocks, and 1 tindirect block | |
927 | */ | |
928 | return DIV_ROUND_UP(nrblocks, | |
929 | EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4; | |
930 | } | |
931 | /* | |
932 | * if nrblocks are not contiguous, worse case, each block touch | |
933 | * a indirect block, and each indirect block touch a double indirect | |
934 | * block, plus a triple indirect block | |
935 | */ | |
936 | indirects = nrblocks * 2 + 1; | |
937 | return indirects; | |
938 | } | |
939 | ||
940 | /* | |
941 | * Truncate transactions can be complex and absolutely huge. So we need to | |
942 | * be able to restart the transaction at a conventient checkpoint to make | |
943 | * sure we don't overflow the journal. | |
944 | * | |
945 | * start_transaction gets us a new handle for a truncate transaction, | |
946 | * and extend_transaction tries to extend the existing one a bit. If | |
947 | * extend fails, we need to propagate the failure up and restart the | |
948 | * transaction in the top-level truncate loop. --sct | |
949 | */ | |
950 | static handle_t *start_transaction(struct inode *inode) | |
951 | { | |
952 | handle_t *result; | |
953 | ||
954 | result = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)); | |
955 | if (!IS_ERR(result)) | |
956 | return result; | |
957 | ||
958 | ext4_std_error(inode->i_sb, PTR_ERR(result)); | |
959 | return result; | |
960 | } | |
961 | ||
962 | /* | |
963 | * Try to extend this transaction for the purposes of truncation. | |
964 | * | |
965 | * Returns 0 if we managed to create more room. If we can't create more | |
966 | * room, and the transaction must be restarted we return 1. | |
967 | */ | |
968 | static int try_to_extend_transaction(handle_t *handle, struct inode *inode) | |
969 | { | |
970 | if (!ext4_handle_valid(handle)) | |
971 | return 0; | |
972 | if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1)) | |
973 | return 0; | |
974 | if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode))) | |
975 | return 0; | |
976 | return 1; | |
977 | } | |
978 | ||
979 | /* | |
980 | * Probably it should be a library function... search for first non-zero word | |
981 | * or memcmp with zero_page, whatever is better for particular architecture. | |
982 | * Linus? | |
983 | */ | |
984 | static inline int all_zeroes(__le32 *p, __le32 *q) | |
985 | { | |
986 | while (p < q) | |
987 | if (*p++) | |
988 | return 0; | |
989 | return 1; | |
990 | } | |
991 | ||
992 | /** | |
993 | * ext4_find_shared - find the indirect blocks for partial truncation. | |
994 | * @inode: inode in question | |
995 | * @depth: depth of the affected branch | |
996 | * @offsets: offsets of pointers in that branch (see ext4_block_to_path) | |
997 | * @chain: place to store the pointers to partial indirect blocks | |
998 | * @top: place to the (detached) top of branch | |
999 | * | |
1000 | * This is a helper function used by ext4_truncate(). | |
1001 | * | |
1002 | * When we do truncate() we may have to clean the ends of several | |
1003 | * indirect blocks but leave the blocks themselves alive. Block is | |
1004 | * partially truncated if some data below the new i_size is referred | |
1005 | * from it (and it is on the path to the first completely truncated | |
1006 | * data block, indeed). We have to free the top of that path along | |
1007 | * with everything to the right of the path. Since no allocation | |
1008 | * past the truncation point is possible until ext4_truncate() | |
1009 | * finishes, we may safely do the latter, but top of branch may | |
1010 | * require special attention - pageout below the truncation point | |
1011 | * might try to populate it. | |
1012 | * | |
1013 | * We atomically detach the top of branch from the tree, store the | |
1014 | * block number of its root in *@top, pointers to buffer_heads of | |
1015 | * partially truncated blocks - in @chain[].bh and pointers to | |
1016 | * their last elements that should not be removed - in | |
1017 | * @chain[].p. Return value is the pointer to last filled element | |
1018 | * of @chain. | |
1019 | * | |
1020 | * The work left to caller to do the actual freeing of subtrees: | |
1021 | * a) free the subtree starting from *@top | |
1022 | * b) free the subtrees whose roots are stored in | |
1023 | * (@chain[i].p+1 .. end of @chain[i].bh->b_data) | |
1024 | * c) free the subtrees growing from the inode past the @chain[0]. | |
1025 | * (no partially truncated stuff there). */ | |
1026 | ||
1027 | static Indirect *ext4_find_shared(struct inode *inode, int depth, | |
1028 | ext4_lblk_t offsets[4], Indirect chain[4], | |
1029 | __le32 *top) | |
1030 | { | |
1031 | Indirect *partial, *p; | |
1032 | int k, err; | |
1033 | ||
1034 | *top = 0; | |
1035 | /* Make k index the deepest non-null offset + 1 */ | |
1036 | for (k = depth; k > 1 && !offsets[k-1]; k--) | |
1037 | ; | |
1038 | partial = ext4_get_branch(inode, k, offsets, chain, &err); | |
1039 | /* Writer: pointers */ | |
1040 | if (!partial) | |
1041 | partial = chain + k-1; | |
1042 | /* | |
1043 | * If the branch acquired continuation since we've looked at it - | |
1044 | * fine, it should all survive and (new) top doesn't belong to us. | |
1045 | */ | |
1046 | if (!partial->key && *partial->p) | |
1047 | /* Writer: end */ | |
1048 | goto no_top; | |
1049 | for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--) | |
1050 | ; | |
1051 | /* | |
1052 | * OK, we've found the last block that must survive. The rest of our | |
1053 | * branch should be detached before unlocking. However, if that rest | |
1054 | * of branch is all ours and does not grow immediately from the inode | |
1055 | * it's easier to cheat and just decrement partial->p. | |
1056 | */ | |
1057 | if (p == chain + k - 1 && p > chain) { | |
1058 | p->p--; | |
1059 | } else { | |
1060 | *top = *p->p; | |
1061 | /* Nope, don't do this in ext4. Must leave the tree intact */ | |
1062 | #if 0 | |
1063 | *p->p = 0; | |
1064 | #endif | |
1065 | } | |
1066 | /* Writer: end */ | |
1067 | ||
1068 | while (partial > p) { | |
1069 | brelse(partial->bh); | |
1070 | partial--; | |
1071 | } | |
1072 | no_top: | |
1073 | return partial; | |
1074 | } | |
1075 | ||
1076 | /* | |
1077 | * Zero a number of block pointers in either an inode or an indirect block. | |
1078 | * If we restart the transaction we must again get write access to the | |
1079 | * indirect block for further modification. | |
1080 | * | |
1081 | * We release `count' blocks on disk, but (last - first) may be greater | |
1082 | * than `count' because there can be holes in there. | |
1083 | * | |
1084 | * Return 0 on success, 1 on invalid block range | |
1085 | * and < 0 on fatal error. | |
1086 | */ | |
1087 | static int ext4_clear_blocks(handle_t *handle, struct inode *inode, | |
1088 | struct buffer_head *bh, | |
1089 | ext4_fsblk_t block_to_free, | |
1090 | unsigned long count, __le32 *first, | |
1091 | __le32 *last) | |
1092 | { | |
1093 | __le32 *p; | |
1094 | int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED; | |
1095 | int err; | |
1096 | ||
1097 | if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) | |
1098 | flags |= EXT4_FREE_BLOCKS_METADATA; | |
1099 | ||
1100 | if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free, | |
1101 | count)) { | |
1102 | EXT4_ERROR_INODE(inode, "attempt to clear invalid " | |
1103 | "blocks %llu len %lu", | |
1104 | (unsigned long long) block_to_free, count); | |
1105 | return 1; | |
1106 | } | |
1107 | ||
1108 | if (try_to_extend_transaction(handle, inode)) { | |
1109 | if (bh) { | |
1110 | BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); | |
1111 | err = ext4_handle_dirty_metadata(handle, inode, bh); | |
1112 | if (unlikely(err)) | |
1113 | goto out_err; | |
1114 | } | |
1115 | err = ext4_mark_inode_dirty(handle, inode); | |
1116 | if (unlikely(err)) | |
1117 | goto out_err; | |
1118 | err = ext4_truncate_restart_trans(handle, inode, | |
1119 | ext4_blocks_for_truncate(inode)); | |
1120 | if (unlikely(err)) | |
1121 | goto out_err; | |
1122 | if (bh) { | |
1123 | BUFFER_TRACE(bh, "retaking write access"); | |
1124 | err = ext4_journal_get_write_access(handle, bh); | |
1125 | if (unlikely(err)) | |
1126 | goto out_err; | |
1127 | } | |
1128 | } | |
1129 | ||
1130 | for (p = first; p < last; p++) | |
1131 | *p = 0; | |
1132 | ||
1133 | ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags); | |
1134 | return 0; | |
1135 | out_err: | |
1136 | ext4_std_error(inode->i_sb, err); | |
1137 | return err; | |
1138 | } | |
1139 | ||
1140 | /** | |
1141 | * ext4_free_data - free a list of data blocks | |
1142 | * @handle: handle for this transaction | |
1143 | * @inode: inode we are dealing with | |
1144 | * @this_bh: indirect buffer_head which contains *@first and *@last | |
1145 | * @first: array of block numbers | |
1146 | * @last: points immediately past the end of array | |
1147 | * | |
1148 | * We are freeing all blocks referred from that array (numbers are stored as | |
1149 | * little-endian 32-bit) and updating @inode->i_blocks appropriately. | |
1150 | * | |
1151 | * We accumulate contiguous runs of blocks to free. Conveniently, if these | |
1152 | * blocks are contiguous then releasing them at one time will only affect one | |
1153 | * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't | |
1154 | * actually use a lot of journal space. | |
1155 | * | |
1156 | * @this_bh will be %NULL if @first and @last point into the inode's direct | |
1157 | * block pointers. | |
1158 | */ | |
1159 | static void ext4_free_data(handle_t *handle, struct inode *inode, | |
1160 | struct buffer_head *this_bh, | |
1161 | __le32 *first, __le32 *last) | |
1162 | { | |
1163 | ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */ | |
1164 | unsigned long count = 0; /* Number of blocks in the run */ | |
1165 | __le32 *block_to_free_p = NULL; /* Pointer into inode/ind | |
1166 | corresponding to | |
1167 | block_to_free */ | |
1168 | ext4_fsblk_t nr; /* Current block # */ | |
1169 | __le32 *p; /* Pointer into inode/ind | |
1170 | for current block */ | |
1171 | int err = 0; | |
1172 | ||
1173 | if (this_bh) { /* For indirect block */ | |
1174 | BUFFER_TRACE(this_bh, "get_write_access"); | |
1175 | err = ext4_journal_get_write_access(handle, this_bh); | |
1176 | /* Important: if we can't update the indirect pointers | |
1177 | * to the blocks, we can't free them. */ | |
1178 | if (err) | |
1179 | return; | |
1180 | } | |
1181 | ||
1182 | for (p = first; p < last; p++) { | |
1183 | nr = le32_to_cpu(*p); | |
1184 | if (nr) { | |
1185 | /* accumulate blocks to free if they're contiguous */ | |
1186 | if (count == 0) { | |
1187 | block_to_free = nr; | |
1188 | block_to_free_p = p; | |
1189 | count = 1; | |
1190 | } else if (nr == block_to_free + count) { | |
1191 | count++; | |
1192 | } else { | |
1193 | err = ext4_clear_blocks(handle, inode, this_bh, | |
1194 | block_to_free, count, | |
1195 | block_to_free_p, p); | |
1196 | if (err) | |
1197 | break; | |
1198 | block_to_free = nr; | |
1199 | block_to_free_p = p; | |
1200 | count = 1; | |
1201 | } | |
1202 | } | |
1203 | } | |
1204 | ||
1205 | if (!err && count > 0) | |
1206 | err = ext4_clear_blocks(handle, inode, this_bh, block_to_free, | |
1207 | count, block_to_free_p, p); | |
1208 | if (err < 0) | |
1209 | /* fatal error */ | |
1210 | return; | |
1211 | ||
1212 | if (this_bh) { | |
1213 | BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata"); | |
1214 | ||
1215 | /* | |
1216 | * The buffer head should have an attached journal head at this | |
1217 | * point. However, if the data is corrupted and an indirect | |
1218 | * block pointed to itself, it would have been detached when | |
1219 | * the block was cleared. Check for this instead of OOPSing. | |
1220 | */ | |
1221 | if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh)) | |
1222 | ext4_handle_dirty_metadata(handle, inode, this_bh); | |
1223 | else | |
1224 | EXT4_ERROR_INODE(inode, | |
1225 | "circular indirect block detected at " | |
1226 | "block %llu", | |
1227 | (unsigned long long) this_bh->b_blocknr); | |
1228 | } | |
1229 | } | |
1230 | ||
1231 | /** | |
1232 | * ext4_free_branches - free an array of branches | |
1233 | * @handle: JBD handle for this transaction | |
1234 | * @inode: inode we are dealing with | |
1235 | * @parent_bh: the buffer_head which contains *@first and *@last | |
1236 | * @first: array of block numbers | |
1237 | * @last: pointer immediately past the end of array | |
1238 | * @depth: depth of the branches to free | |
1239 | * | |
1240 | * We are freeing all blocks referred from these branches (numbers are | |
1241 | * stored as little-endian 32-bit) and updating @inode->i_blocks | |
1242 | * appropriately. | |
1243 | */ | |
1244 | static void ext4_free_branches(handle_t *handle, struct inode *inode, | |
1245 | struct buffer_head *parent_bh, | |
1246 | __le32 *first, __le32 *last, int depth) | |
1247 | { | |
1248 | ext4_fsblk_t nr; | |
1249 | __le32 *p; | |
1250 | ||
1251 | if (ext4_handle_is_aborted(handle)) | |
1252 | return; | |
1253 | ||
1254 | if (depth--) { | |
1255 | struct buffer_head *bh; | |
1256 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); | |
1257 | p = last; | |
1258 | while (--p >= first) { | |
1259 | nr = le32_to_cpu(*p); | |
1260 | if (!nr) | |
1261 | continue; /* A hole */ | |
1262 | ||
1263 | if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), | |
1264 | nr, 1)) { | |
1265 | EXT4_ERROR_INODE(inode, | |
1266 | "invalid indirect mapped " | |
1267 | "block %lu (level %d)", | |
1268 | (unsigned long) nr, depth); | |
1269 | break; | |
1270 | } | |
1271 | ||
1272 | /* Go read the buffer for the next level down */ | |
1273 | bh = sb_bread(inode->i_sb, nr); | |
1274 | ||
1275 | /* | |
1276 | * A read failure? Report error and clear slot | |
1277 | * (should be rare). | |
1278 | */ | |
1279 | if (!bh) { | |
1280 | EXT4_ERROR_INODE_BLOCK(inode, nr, | |
1281 | "Read failure"); | |
1282 | continue; | |
1283 | } | |
1284 | ||
1285 | /* This zaps the entire block. Bottom up. */ | |
1286 | BUFFER_TRACE(bh, "free child branches"); | |
1287 | ext4_free_branches(handle, inode, bh, | |
1288 | (__le32 *) bh->b_data, | |
1289 | (__le32 *) bh->b_data + addr_per_block, | |
1290 | depth); | |
1291 | brelse(bh); | |
1292 | ||
1293 | /* | |
1294 | * Everything below this this pointer has been | |
1295 | * released. Now let this top-of-subtree go. | |
1296 | * | |
1297 | * We want the freeing of this indirect block to be | |
1298 | * atomic in the journal with the updating of the | |
1299 | * bitmap block which owns it. So make some room in | |
1300 | * the journal. | |
1301 | * | |
1302 | * We zero the parent pointer *after* freeing its | |
1303 | * pointee in the bitmaps, so if extend_transaction() | |
1304 | * for some reason fails to put the bitmap changes and | |
1305 | * the release into the same transaction, recovery | |
1306 | * will merely complain about releasing a free block, | |
1307 | * rather than leaking blocks. | |
1308 | */ | |
1309 | if (ext4_handle_is_aborted(handle)) | |
1310 | return; | |
1311 | if (try_to_extend_transaction(handle, inode)) { | |
1312 | ext4_mark_inode_dirty(handle, inode); | |
1313 | ext4_truncate_restart_trans(handle, inode, | |
1314 | ext4_blocks_for_truncate(inode)); | |
1315 | } | |
1316 | ||
1317 | /* | |
1318 | * The forget flag here is critical because if | |
1319 | * we are journaling (and not doing data | |
1320 | * journaling), we have to make sure a revoke | |
1321 | * record is written to prevent the journal | |
1322 | * replay from overwriting the (former) | |
1323 | * indirect block if it gets reallocated as a | |
1324 | * data block. This must happen in the same | |
1325 | * transaction where the data blocks are | |
1326 | * actually freed. | |
1327 | */ | |
1328 | ext4_free_blocks(handle, inode, NULL, nr, 1, | |
1329 | EXT4_FREE_BLOCKS_METADATA| | |
1330 | EXT4_FREE_BLOCKS_FORGET); | |
1331 | ||
1332 | if (parent_bh) { | |
1333 | /* | |
1334 | * The block which we have just freed is | |
1335 | * pointed to by an indirect block: journal it | |
1336 | */ | |
1337 | BUFFER_TRACE(parent_bh, "get_write_access"); | |
1338 | if (!ext4_journal_get_write_access(handle, | |
1339 | parent_bh)){ | |
1340 | *p = 0; | |
1341 | BUFFER_TRACE(parent_bh, | |
1342 | "call ext4_handle_dirty_metadata"); | |
1343 | ext4_handle_dirty_metadata(handle, | |
1344 | inode, | |
1345 | parent_bh); | |
1346 | } | |
1347 | } | |
1348 | } | |
1349 | } else { | |
1350 | /* We have reached the bottom of the tree. */ | |
1351 | BUFFER_TRACE(parent_bh, "free data blocks"); | |
1352 | ext4_free_data(handle, inode, parent_bh, first, last); | |
1353 | } | |
1354 | } | |
1355 | ||
1356 | void ext4_ind_truncate(struct inode *inode) | |
1357 | { | |
1358 | handle_t *handle; | |
1359 | struct ext4_inode_info *ei = EXT4_I(inode); | |
1360 | __le32 *i_data = ei->i_data; | |
1361 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); | |
1362 | struct address_space *mapping = inode->i_mapping; | |
1363 | ext4_lblk_t offsets[4]; | |
1364 | Indirect chain[4]; | |
1365 | Indirect *partial; | |
1366 | __le32 nr = 0; | |
1367 | int n = 0; | |
1368 | ext4_lblk_t last_block, max_block; | |
189e868f | 1369 | loff_t page_len; |
dae1e52c | 1370 | unsigned blocksize = inode->i_sb->s_blocksize; |
189e868f | 1371 | int err; |
dae1e52c AG |
1372 | |
1373 | handle = start_transaction(inode); | |
1374 | if (IS_ERR(handle)) | |
1375 | return; /* AKPM: return what? */ | |
1376 | ||
1377 | last_block = (inode->i_size + blocksize-1) | |
1378 | >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); | |
1379 | max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1) | |
1380 | >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); | |
1381 | ||
189e868f AH |
1382 | if (inode->i_size % PAGE_CACHE_SIZE != 0) { |
1383 | page_len = PAGE_CACHE_SIZE - | |
1384 | (inode->i_size & (PAGE_CACHE_SIZE - 1)); | |
1385 | ||
1386 | err = ext4_discard_partial_page_buffers(handle, | |
1387 | mapping, inode->i_size, page_len, 0); | |
1388 | ||
1389 | if (err) | |
dae1e52c | 1390 | goto out_stop; |
189e868f | 1391 | } |
dae1e52c AG |
1392 | |
1393 | if (last_block != max_block) { | |
1394 | n = ext4_block_to_path(inode, last_block, offsets, NULL); | |
1395 | if (n == 0) | |
1396 | goto out_stop; /* error */ | |
1397 | } | |
1398 | ||
1399 | /* | |
1400 | * OK. This truncate is going to happen. We add the inode to the | |
1401 | * orphan list, so that if this truncate spans multiple transactions, | |
1402 | * and we crash, we will resume the truncate when the filesystem | |
1403 | * recovers. It also marks the inode dirty, to catch the new size. | |
1404 | * | |
1405 | * Implication: the file must always be in a sane, consistent | |
1406 | * truncatable state while each transaction commits. | |
1407 | */ | |
1408 | if (ext4_orphan_add(handle, inode)) | |
1409 | goto out_stop; | |
1410 | ||
1411 | /* | |
1412 | * From here we block out all ext4_get_block() callers who want to | |
1413 | * modify the block allocation tree. | |
1414 | */ | |
1415 | down_write(&ei->i_data_sem); | |
1416 | ||
1417 | ext4_discard_preallocations(inode); | |
51865fda | 1418 | ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block); |
dae1e52c AG |
1419 | |
1420 | /* | |
1421 | * The orphan list entry will now protect us from any crash which | |
1422 | * occurs before the truncate completes, so it is now safe to propagate | |
1423 | * the new, shorter inode size (held for now in i_size) into the | |
1424 | * on-disk inode. We do this via i_disksize, which is the value which | |
1425 | * ext4 *really* writes onto the disk inode. | |
1426 | */ | |
1427 | ei->i_disksize = inode->i_size; | |
1428 | ||
1429 | if (last_block == max_block) { | |
1430 | /* | |
1431 | * It is unnecessary to free any data blocks if last_block is | |
1432 | * equal to the indirect block limit. | |
1433 | */ | |
1434 | goto out_unlock; | |
1435 | } else if (n == 1) { /* direct blocks */ | |
1436 | ext4_free_data(handle, inode, NULL, i_data+offsets[0], | |
1437 | i_data + EXT4_NDIR_BLOCKS); | |
1438 | goto do_indirects; | |
1439 | } | |
1440 | ||
1441 | partial = ext4_find_shared(inode, n, offsets, chain, &nr); | |
1442 | /* Kill the top of shared branch (not detached) */ | |
1443 | if (nr) { | |
1444 | if (partial == chain) { | |
1445 | /* Shared branch grows from the inode */ | |
1446 | ext4_free_branches(handle, inode, NULL, | |
1447 | &nr, &nr+1, (chain+n-1) - partial); | |
1448 | *partial->p = 0; | |
1449 | /* | |
1450 | * We mark the inode dirty prior to restart, | |
1451 | * and prior to stop. No need for it here. | |
1452 | */ | |
1453 | } else { | |
1454 | /* Shared branch grows from an indirect block */ | |
1455 | BUFFER_TRACE(partial->bh, "get_write_access"); | |
1456 | ext4_free_branches(handle, inode, partial->bh, | |
1457 | partial->p, | |
1458 | partial->p+1, (chain+n-1) - partial); | |
1459 | } | |
1460 | } | |
1461 | /* Clear the ends of indirect blocks on the shared branch */ | |
1462 | while (partial > chain) { | |
1463 | ext4_free_branches(handle, inode, partial->bh, partial->p + 1, | |
1464 | (__le32*)partial->bh->b_data+addr_per_block, | |
1465 | (chain+n-1) - partial); | |
1466 | BUFFER_TRACE(partial->bh, "call brelse"); | |
1467 | brelse(partial->bh); | |
1468 | partial--; | |
1469 | } | |
1470 | do_indirects: | |
1471 | /* Kill the remaining (whole) subtrees */ | |
1472 | switch (offsets[0]) { | |
1473 | default: | |
1474 | nr = i_data[EXT4_IND_BLOCK]; | |
1475 | if (nr) { | |
1476 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1); | |
1477 | i_data[EXT4_IND_BLOCK] = 0; | |
1478 | } | |
1479 | case EXT4_IND_BLOCK: | |
1480 | nr = i_data[EXT4_DIND_BLOCK]; | |
1481 | if (nr) { | |
1482 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2); | |
1483 | i_data[EXT4_DIND_BLOCK] = 0; | |
1484 | } | |
1485 | case EXT4_DIND_BLOCK: | |
1486 | nr = i_data[EXT4_TIND_BLOCK]; | |
1487 | if (nr) { | |
1488 | ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3); | |
1489 | i_data[EXT4_TIND_BLOCK] = 0; | |
1490 | } | |
1491 | case EXT4_TIND_BLOCK: | |
1492 | ; | |
1493 | } | |
1494 | ||
1495 | out_unlock: | |
1496 | up_write(&ei->i_data_sem); | |
1497 | inode->i_mtime = inode->i_ctime = ext4_current_time(inode); | |
1498 | ext4_mark_inode_dirty(handle, inode); | |
1499 | ||
1500 | /* | |
1501 | * In a multi-transaction truncate, we only make the final transaction | |
1502 | * synchronous | |
1503 | */ | |
1504 | if (IS_SYNC(inode)) | |
1505 | ext4_handle_sync(handle); | |
1506 | out_stop: | |
1507 | /* | |
1508 | * If this was a simple ftruncate(), and the file will remain alive | |
1509 | * then we need to clear up the orphan record which we created above. | |
1510 | * However, if this was a real unlink then we were called by | |
1511 | * ext4_delete_inode(), and we allow that function to clean up the | |
1512 | * orphan info for us. | |
1513 | */ | |
1514 | if (inode->i_nlink) | |
1515 | ext4_orphan_del(handle, inode); | |
1516 | ||
1517 | ext4_journal_stop(handle); | |
1518 | trace_ext4_truncate_exit(inode); | |
1519 | } | |
1520 | ||
8bad6fc8 ZL |
1521 | static int free_hole_blocks(handle_t *handle, struct inode *inode, |
1522 | struct buffer_head *parent_bh, __le32 *i_data, | |
1523 | int level, ext4_lblk_t first, | |
1524 | ext4_lblk_t count, int max) | |
1525 | { | |
1526 | struct buffer_head *bh = NULL; | |
1527 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); | |
1528 | int ret = 0; | |
1529 | int i, inc; | |
1530 | ext4_lblk_t offset; | |
1531 | __le32 blk; | |
1532 | ||
1533 | inc = 1 << ((EXT4_BLOCK_SIZE_BITS(inode->i_sb) - 2) * level); | |
1534 | for (i = 0, offset = 0; i < max; i++, i_data++, offset += inc) { | |
1535 | if (offset >= count + first) | |
1536 | break; | |
1537 | if (*i_data == 0 || (offset + inc) <= first) | |
1538 | continue; | |
1539 | blk = *i_data; | |
1540 | if (level > 0) { | |
1541 | ext4_lblk_t first2; | |
1542 | bh = sb_bread(inode->i_sb, blk); | |
1543 | if (!bh) { | |
1544 | EXT4_ERROR_INODE_BLOCK(inode, blk, | |
1545 | "Read failure"); | |
1546 | return -EIO; | |
1547 | } | |
1548 | first2 = (first > offset) ? first - offset : 0; | |
1549 | ret = free_hole_blocks(handle, inode, bh, | |
1550 | (__le32 *)bh->b_data, level - 1, | |
1551 | first2, count - offset, | |
1552 | inode->i_sb->s_blocksize >> 2); | |
1553 | if (ret) { | |
1554 | brelse(bh); | |
1555 | goto err; | |
1556 | } | |
1557 | } | |
1558 | if (level == 0 || | |
1559 | (bh && all_zeroes((__le32 *)bh->b_data, | |
1560 | (__le32 *)bh->b_data + addr_per_block))) { | |
1561 | ext4_free_data(handle, inode, parent_bh, &blk, &blk+1); | |
1562 | *i_data = 0; | |
1563 | } | |
1564 | brelse(bh); | |
1565 | bh = NULL; | |
1566 | } | |
1567 | ||
1568 | err: | |
1569 | return ret; | |
1570 | } | |
1571 | ||
1572 | static int ext4_free_hole_blocks(handle_t *handle, struct inode *inode, | |
1573 | ext4_lblk_t first, ext4_lblk_t stop) | |
1574 | { | |
1575 | int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); | |
1576 | int level, ret = 0; | |
1577 | int num = EXT4_NDIR_BLOCKS; | |
1578 | ext4_lblk_t count, max = EXT4_NDIR_BLOCKS; | |
1579 | __le32 *i_data = EXT4_I(inode)->i_data; | |
1580 | ||
1581 | count = stop - first; | |
1582 | for (level = 0; level < 4; level++, max *= addr_per_block) { | |
1583 | if (first < max) { | |
1584 | ret = free_hole_blocks(handle, inode, NULL, i_data, | |
1585 | level, first, count, num); | |
1586 | if (ret) | |
1587 | goto err; | |
1588 | if (count > max - first) | |
1589 | count -= max - first; | |
1590 | else | |
1591 | break; | |
1592 | first = 0; | |
1593 | } else { | |
1594 | first -= max; | |
1595 | } | |
1596 | i_data += num; | |
1597 | if (level == 0) { | |
1598 | num = 1; | |
1599 | max = 1; | |
1600 | } | |
1601 | } | |
1602 | ||
1603 | err: | |
1604 | return ret; | |
1605 | } | |
1606 | ||
1607 | int ext4_ind_punch_hole(struct file *file, loff_t offset, loff_t length) | |
1608 | { | |
1609 | struct inode *inode = file->f_path.dentry->d_inode; | |
1610 | struct super_block *sb = inode->i_sb; | |
1611 | ext4_lblk_t first_block, stop_block; | |
1612 | struct address_space *mapping = inode->i_mapping; | |
1613 | handle_t *handle = NULL; | |
1614 | loff_t first_page, last_page, page_len; | |
1615 | loff_t first_page_offset, last_page_offset; | |
1616 | int err = 0; | |
1617 | ||
1618 | /* | |
1619 | * Write out all dirty pages to avoid race conditions | |
1620 | * Then release them. | |
1621 | */ | |
1622 | if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { | |
1623 | err = filemap_write_and_wait_range(mapping, | |
1624 | offset, offset + length - 1); | |
1625 | if (err) | |
1626 | return err; | |
1627 | } | |
1628 | ||
1629 | mutex_lock(&inode->i_mutex); | |
1630 | /* It's not possible punch hole on append only file */ | |
1631 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) { | |
1632 | err = -EPERM; | |
1633 | goto out_mutex; | |
1634 | } | |
1635 | if (IS_SWAPFILE(inode)) { | |
1636 | err = -ETXTBSY; | |
1637 | goto out_mutex; | |
1638 | } | |
1639 | ||
1640 | /* No need to punch hole beyond i_size */ | |
1641 | if (offset >= inode->i_size) | |
1642 | goto out_mutex; | |
1643 | ||
1644 | /* | |
1645 | * If the hole extents beyond i_size, set the hole | |
1646 | * to end after the page that contains i_size | |
1647 | */ | |
1648 | if (offset + length > inode->i_size) { | |
1649 | length = inode->i_size + | |
1650 | PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) - | |
1651 | offset; | |
1652 | } | |
1653 | ||
1654 | first_page = (offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1655 | last_page = (offset + length) >> PAGE_CACHE_SHIFT; | |
1656 | ||
1657 | first_page_offset = first_page << PAGE_CACHE_SHIFT; | |
1658 | last_page_offset = last_page << PAGE_CACHE_SHIFT; | |
1659 | ||
1660 | /* Now release the pages */ | |
1661 | if (last_page_offset > first_page_offset) { | |
1662 | truncate_pagecache_range(inode, first_page_offset, | |
1663 | last_page_offset - 1); | |
1664 | } | |
1665 | ||
1666 | /* Wait all existing dio works, newcomers will block on i_mutex */ | |
1667 | inode_dio_wait(inode); | |
1668 | ||
1669 | handle = start_transaction(inode); | |
1670 | if (IS_ERR(handle)) | |
1671 | goto out_mutex; | |
1672 | ||
1673 | /* | |
1674 | * Now we need to zero out the non-page-aligned data in the | |
1675 | * pages at the start and tail of the hole, and unmap the buffer | |
1676 | * heads for the block aligned regions of the page that were | |
1677 | * completely zerod. | |
1678 | */ | |
1679 | if (first_page > last_page) { | |
1680 | /* | |
1681 | * If the file space being truncated is contained within a page | |
1682 | * just zero out and unmap the middle of that page | |
1683 | */ | |
1684 | err = ext4_discard_partial_page_buffers(handle, | |
1685 | mapping, offset, length, 0); | |
1686 | if (err) | |
1687 | goto out; | |
1688 | } else { | |
1689 | /* | |
1690 | * Zero out and unmap the paritial page that contains | |
1691 | * the start of the hole | |
1692 | */ | |
1693 | page_len = first_page_offset - offset; | |
1694 | if (page_len > 0) { | |
1695 | err = ext4_discard_partial_page_buffers(handle, mapping, | |
1696 | offset, page_len, 0); | |
1697 | if (err) | |
1698 | goto out; | |
1699 | } | |
1700 | ||
1701 | /* | |
1702 | * Zero out and unmap the partial page that contains | |
1703 | * the end of the hole | |
1704 | */ | |
1705 | page_len = offset + length - last_page_offset; | |
1706 | if (page_len > 0) { | |
1707 | err = ext4_discard_partial_page_buffers(handle, mapping, | |
1708 | last_page_offset, page_len, 0); | |
1709 | if (err) | |
1710 | goto out; | |
1711 | } | |
1712 | } | |
1713 | ||
1714 | /* | |
1715 | * If i_size contained in the last page, we need to | |
1716 | * unmap and zero the paritial page after i_size | |
1717 | */ | |
1718 | if (inode->i_size >> PAGE_CACHE_SHIFT == last_page && | |
1719 | inode->i_size % PAGE_CACHE_SIZE != 0) { | |
1720 | page_len = PAGE_CACHE_SIZE - | |
1721 | (inode->i_size & (PAGE_CACHE_SIZE - 1)); | |
1722 | if (page_len > 0) { | |
1723 | err = ext4_discard_partial_page_buffers(handle, | |
1724 | mapping, inode->i_size, page_len, 0); | |
1725 | if (err) | |
1726 | goto out; | |
1727 | } | |
1728 | } | |
1729 | ||
1730 | first_block = (offset + sb->s_blocksize - 1) >> | |
1731 | EXT4_BLOCK_SIZE_BITS(sb); | |
1732 | stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb); | |
1733 | ||
1734 | if (first_block >= stop_block) | |
1735 | goto out; | |
1736 | ||
1737 | down_write(&EXT4_I(inode)->i_data_sem); | |
1738 | ext4_discard_preallocations(inode); | |
1739 | ||
1740 | err = ext4_es_remove_extent(inode, first_block, | |
1741 | stop_block - first_block); | |
1742 | err = ext4_free_hole_blocks(handle, inode, first_block, stop_block); | |
1743 | ||
1744 | ext4_discard_preallocations(inode); | |
1745 | ||
1746 | if (IS_SYNC(inode)) | |
1747 | ext4_handle_sync(handle); | |
1748 | ||
1749 | up_write(&EXT4_I(inode)->i_data_sem); | |
1750 | ||
1751 | out: | |
1752 | inode->i_mtime = inode->i_ctime = ext4_current_time(inode); | |
1753 | ext4_mark_inode_dirty(handle, inode); | |
1754 | ext4_journal_stop(handle); | |
1755 | ||
1756 | out_mutex: | |
1757 | mutex_unlock(&inode->i_mutex); | |
1758 | ||
1759 | return err; | |
1760 | } |