Branch data Line data Source code
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 : :
23 : : #include <linux/aio.h>
24 : : #include "ext4_jbd2.h"
25 : : #include "truncate.h"
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 : 0 : p->key = *(p->p = v);
38 : 0 : 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 : 0 : 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 : 0 : int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
77 : 0 : int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
78 : : const long direct_blocks = EXT4_NDIR_BLOCKS,
79 : : indirect_blocks = ptrs,
80 : 0 : double_blocks = (1 << (ptrs_bits * 2));
81 : : int n = 0;
82 : : int final = 0;
83 : :
84 [ # # ]: 0 : if (i_block < direct_blocks) {
85 : 0 : offsets[n++] = i_block;
86 : : final = direct_blocks;
87 [ # # ]: 0 : } else if ((i_block -= direct_blocks) < indirect_blocks) {
88 : 0 : offsets[n++] = EXT4_IND_BLOCK;
89 : 0 : offsets[n++] = i_block;
90 : : final = ptrs;
91 [ # # ]: 0 : } else if ((i_block -= indirect_blocks) < double_blocks) {
92 : 0 : offsets[n++] = EXT4_DIND_BLOCK;
93 : 0 : offsets[n++] = i_block >> ptrs_bits;
94 : 0 : offsets[n++] = i_block & (ptrs - 1);
95 : : final = ptrs;
96 [ # # ]: 0 : } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
97 : 0 : offsets[n++] = EXT4_TIND_BLOCK;
98 : 0 : offsets[n++] = i_block >> (ptrs_bits * 2);
99 : 0 : offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
100 : 0 : offsets[n++] = i_block & (ptrs - 1);
101 : : final = ptrs;
102 : : } else {
103 : 0 : 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 [ # # ]: 0 : if (boundary)
108 : 0 : *boundary = final - 1 - (i_block & (ptrs - 1));
109 : 0 : 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 : 0 : static Indirect *ext4_get_branch(struct inode *inode, int depth,
143 : : ext4_lblk_t *offsets,
144 : : Indirect chain[4], int *err)
145 : : {
146 : 0 : struct super_block *sb = inode->i_sb;
147 : : Indirect *p = chain;
148 : : struct buffer_head *bh;
149 : : int ret = -EIO;
150 : :
151 : 0 : *err = 0;
152 : : /* i_data is not going away, no lock needed */
153 : 0 : add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
154 [ # # ]: 0 : if (!p->key)
155 : : goto no_block;
156 [ # # ]: 0 : while (--depth) {
157 : 0 : bh = sb_getblk(sb, le32_to_cpu(p->key));
158 [ # # ]: 0 : if (unlikely(!bh)) {
159 : : ret = -ENOMEM;
160 : : goto failure;
161 : : }
162 : :
163 [ # # ]: 0 : if (!bh_uptodate_or_lock(bh)) {
164 [ # # ]: 0 : if (bh_submit_read(bh) < 0) {
165 : : put_bh(bh);
166 : : goto failure;
167 : : }
168 : : /* validate block references */
169 [ # # ]: 0 : if (ext4_check_indirect_blockref(inode, bh)) {
170 : : put_bh(bh);
171 : : goto failure;
172 : : }
173 : : }
174 : :
175 : 0 : add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
176 : : /* Reader: end */
177 [ # # ]: 0 : if (!p->key)
178 : : goto no_block;
179 : : }
180 : : return NULL;
181 : :
182 : : failure:
183 : 0 : *err = ret;
184 : : no_block:
185 : 0 : 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 : 0 : static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
209 : : {
210 : : struct ext4_inode_info *ei = EXT4_I(inode);
211 [ # # ]: 0 : __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
212 : : __le32 *p;
213 : :
214 : : /* Try to find previous block */
215 [ # # ]: 0 : for (p = ind->p - 1; p >= start; p--) {
216 [ # # ]: 0 : if (*p)
217 : 0 : return le32_to_cpu(*p);
218 : : }
219 : :
220 : : /* No such thing, so let's try location of indirect block */
221 [ # # ]: 0 : if (ind->bh)
222 : 0 : 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 : : */
228 : 0 : return ext4_inode_to_goal_block(inode);
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 : 0 : 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 : 0 : goal = ext4_find_near(inode, partial);
252 : 0 : 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 : 0 : 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 [ # # ]: 0 : if (k > 0) {
278 : : /* right now we don't handle cross boundary allocation */
279 [ # # ]: 0 : if (blks < blocks_to_boundary + 1)
280 : : count += blks;
281 : : else
282 : 0 : count += blocks_to_boundary + 1;
283 : 0 : return count;
284 : : }
285 : :
286 : : count++;
287 [ # # ][ # # ]: 0 : while (count < blks && count <= blocks_to_boundary &&
288 : 0 : le32_to_cpu(*(branch[0].p + count)) == 0) {
289 : 0 : count++;
290 : : }
291 : 0 : return count;
292 : : }
293 : :
294 : : /**
295 : : * 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 : : */
321 : 0 : static 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 : : {
326 : : 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;
331 : :
332 : : /*
333 : : * Set up for the direct block allocation
334 : : */
335 : 0 : memset(&ar, 0, sizeof(ar));
336 : 0 : ar.inode = inode;
337 : 0 : ar.len = *blks;
338 : 0 : ar.logical = iblock;
339 [ # # ]: 0 : if (S_ISREG(inode->i_mode))
340 : 0 : ar.flags = EXT4_MB_HINT_DATA;
341 : :
342 [ # # ]: 0 : for (i = 0; i <= indirect_blks; i++) {
343 [ # # ]: 0 : if (i == indirect_blks) {
344 : 0 : ar.goal = goal;
345 : 0 : new_blocks[i] = ext4_mb_new_blocks(handle, &ar, &err);
346 : : } else
347 : 0 : goal = new_blocks[i] = ext4_new_meta_blocks(handle, inode,
348 : : goal, 0, NULL, &err);
349 [ # # ]: 0 : if (err) {
350 : 0 : i--;
351 : 0 : goto failed;
352 : : }
353 : 0 : branch[i].key = cpu_to_le32(new_blocks[i]);
354 [ # # ]: 0 : if (i == 0)
355 : 0 : continue;
356 : :
357 : 0 : bh = branch[i].bh = sb_getblk(inode->i_sb, new_blocks[i-1]);
358 [ # # ]: 0 : if (unlikely(!bh)) {
359 : 0 : err = -ENOMEM;
360 : 0 : goto failed;
361 : : }
362 : : lock_buffer(bh);
363 : : BUFFER_TRACE(bh, "call get_create_access");
364 : 0 : err = ext4_journal_get_create_access(handle, bh);
365 [ # # ]: 0 : if (err) {
366 : 0 : unlock_buffer(bh);
367 : 0 : goto failed;
368 : : }
369 : :
370 [ # # ]: 0 : memset(bh->b_data, 0, bh->b_size);
371 : 0 : p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
372 : : b = new_blocks[i];
373 : :
374 [ # # ]: 0 : if (i == indirect_blks)
375 : 0 : len = ar.len;
376 [ # # ]: 0 : for (j = 0; j < len; j++)
377 : 0 : *p++ = cpu_to_le32(b++);
378 : :
379 : : BUFFER_TRACE(bh, "marking uptodate");
380 : : set_buffer_uptodate(bh);
381 : 0 : unlock_buffer(bh);
382 : :
383 : : BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
384 : 0 : err = ext4_handle_dirty_metadata(handle, inode, bh);
385 [ # # ]: 0 : if (err)
386 : : goto failed;
387 : : }
388 : 0 : *blks = ar.len;
389 : 0 : return 0;
390 : : failed:
391 [ # # ]: 0 : for (; i >= 0; i--) {
392 [ # # ][ # # ]: 0 : if (i != indirect_blks && branch[i].bh)
393 : 0 : ext4_forget(handle, 1, inode, branch[i].bh,
394 : : branch[i].bh->b_blocknr);
395 [ # # ]: 0 : ext4_free_blocks(handle, inode, NULL, new_blocks[i],
396 : : (i == indirect_blks) ? ar.len : 1, 0);
397 : : }
398 : 0 : return err;
399 : : }
400 : :
401 : : /**
402 : : * ext4_splice_branch - splice the allocated branch onto inode.
403 : : * @handle: handle for this transaction
404 : : * @inode: owner
405 : : * @block: (logical) number of block we are adding
406 : : * @chain: chain of indirect blocks (with a missing link - see
407 : : * ext4_alloc_branch)
408 : : * @where: location of missing link
409 : : * @num: number of indirect blocks we are adding
410 : : * @blks: number of direct blocks we are adding
411 : : *
412 : : * This function fills the missing link and does all housekeeping needed in
413 : : * inode (->i_blocks, etc.). In case of success we end up with the full
414 : : * chain to new block and return 0.
415 : : */
416 : 0 : static int ext4_splice_branch(handle_t *handle, struct inode *inode,
417 : : ext4_lblk_t block, Indirect *where, int num,
418 : : int blks)
419 : : {
420 : : int i;
421 : : int err = 0;
422 : : ext4_fsblk_t current_block;
423 : :
424 : : /*
425 : : * If we're splicing into a [td]indirect block (as opposed to the
426 : : * inode) then we need to get write access to the [td]indirect block
427 : : * before the splice.
428 : : */
429 [ # # ]: 0 : if (where->bh) {
430 : : BUFFER_TRACE(where->bh, "get_write_access");
431 : 0 : err = ext4_journal_get_write_access(handle, where->bh);
432 [ # # ]: 0 : if (err)
433 : : goto err_out;
434 : : }
435 : : /* That's it */
436 : :
437 : 0 : *where->p = where->key;
438 : :
439 : : /*
440 : : * Update the host buffer_head or inode to point to more just allocated
441 : : * direct blocks blocks
442 : : */
443 [ # # ]: 0 : if (num == 0 && blks > 1) {
444 : 0 : current_block = le32_to_cpu(where->key) + 1;
445 [ # # ]: 0 : for (i = 1; i < blks; i++)
446 : 0 : *(where->p + i) = cpu_to_le32(current_block++);
447 : : }
448 : :
449 : : /* We are done with atomic stuff, now do the rest of housekeeping */
450 : : /* had we spliced it onto indirect block? */
451 [ # # ]: 0 : if (where->bh) {
452 : : /*
453 : : * If we spliced it onto an indirect block, we haven't
454 : : * altered the inode. Note however that if it is being spliced
455 : : * onto an indirect block at the very end of the file (the
456 : : * file is growing) then we *will* alter the inode to reflect
457 : : * the new i_size. But that is not done here - it is done in
458 : : * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
459 : : */
460 : : jbd_debug(5, "splicing indirect only\n");
461 : : BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
462 : 0 : err = ext4_handle_dirty_metadata(handle, inode, where->bh);
463 [ # # ]: 0 : if (err)
464 : : goto err_out;
465 : : } else {
466 : : /*
467 : : * OK, we spliced it into the inode itself on a direct block.
468 : : */
469 : 0 : ext4_mark_inode_dirty(handle, inode);
470 : : jbd_debug(5, "splicing direct\n");
471 : : }
472 : : return err;
473 : :
474 : : err_out:
475 [ # # ]: 0 : for (i = 1; i <= num; i++) {
476 : : /*
477 : : * branch[i].bh is newly allocated, so there is no
478 : : * need to revoke the block, which is why we don't
479 : : * need to set EXT4_FREE_BLOCKS_METADATA.
480 : : */
481 : 0 : ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
482 : : EXT4_FREE_BLOCKS_FORGET);
483 : : }
484 : 0 : ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key),
485 : : blks, 0);
486 : :
487 : : return err;
488 : : }
489 : :
490 : : /*
491 : : * The ext4_ind_map_blocks() function handles non-extents inodes
492 : : * (i.e., using the traditional indirect/double-indirect i_blocks
493 : : * scheme) for ext4_map_blocks().
494 : : *
495 : : * Allocation strategy is simple: if we have to allocate something, we will
496 : : * have to go the whole way to leaf. So let's do it before attaching anything
497 : : * to tree, set linkage between the newborn blocks, write them if sync is
498 : : * required, recheck the path, free and repeat if check fails, otherwise
499 : : * set the last missing link (that will protect us from any truncate-generated
500 : : * removals - all blocks on the path are immune now) and possibly force the
501 : : * write on the parent block.
502 : : * That has a nice additional property: no special recovery from the failed
503 : : * allocations is needed - we simply release blocks and do not touch anything
504 : : * reachable from inode.
505 : : *
506 : : * `handle' can be NULL if create == 0.
507 : : *
508 : : * return > 0, # of blocks mapped or allocated.
509 : : * return = 0, if plain lookup failed.
510 : : * return < 0, error case.
511 : : *
512 : : * The ext4_ind_get_blocks() function should be called with
513 : : * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
514 : : * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
515 : : * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
516 : : * blocks.
517 : : */
518 : 0 : int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
519 : : struct ext4_map_blocks *map,
520 : : int flags)
521 : : {
522 : 0 : int err = -EIO;
523 : : ext4_lblk_t offsets[4];
524 : : Indirect chain[4];
525 : : Indirect *partial;
526 : : ext4_fsblk_t goal;
527 : : int indirect_blks;
528 : 0 : int blocks_to_boundary = 0;
529 : : int depth;
530 : 0 : int count = 0;
531 : : ext4_fsblk_t first_block = 0;
532 : :
533 : 0 : trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
534 [ # # ]: 0 : J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
535 [ # # ][ # # ]: 0 : J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
536 : 0 : depth = ext4_block_to_path(inode, map->m_lblk, offsets,
537 : : &blocks_to_boundary);
538 : :
539 [ # # ]: 0 : if (depth == 0)
540 : : goto out;
541 : :
542 : 0 : partial = ext4_get_branch(inode, depth, offsets, chain, &err);
543 : :
544 : : /* Simplest case - block found, no allocation needed */
545 [ # # ]: 0 : if (!partial) {
546 : 0 : first_block = le32_to_cpu(chain[depth - 1].key);
547 : 0 : count++;
548 : : /*map more blocks*/
549 [ # # ][ # # ]: 0 : while (count < map->m_len && count <= blocks_to_boundary) {
550 : : ext4_fsblk_t blk;
551 : :
552 : 0 : blk = le32_to_cpu(*(chain[depth-1].p + count));
553 : :
554 [ # # ]: 0 : if (blk == first_block + count)
555 : 0 : count++;
556 : : else
557 : : break;
558 : : }
559 : : goto got_it;
560 : : }
561 : :
562 : : /* Next simple case - plain lookup or failed read of indirect block */
563 [ # # ][ # # ]: 0 : if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
564 : : goto cleanup;
565 : :
566 : : /*
567 : : * Okay, we need to do block allocation.
568 : : */
569 [ # # ]: 0 : if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
570 : : EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
571 : 0 : EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
572 : : "non-extent mapped inodes with bigalloc");
573 : 0 : return -ENOSPC;
574 : : }
575 : :
576 : : goal = ext4_find_goal(inode, map->m_lblk, partial);
577 : :
578 : : /* the number of blocks need to allocate for [d,t]indirect blocks */
579 : 0 : indirect_blks = (chain + depth) - partial - 1;
580 : :
581 : : /*
582 : : * Next look up the indirect map to count the totoal number of
583 : : * direct blocks to allocate for this branch.
584 : : */
585 : 0 : count = ext4_blks_to_allocate(partial, indirect_blks,
586 : : map->m_len, blocks_to_boundary);
587 : : /*
588 : : * Block out ext4_truncate while we alter the tree
589 : : */
590 : 0 : err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks,
591 : : &count, goal,
592 : 0 : offsets + (partial - chain), partial);
593 : :
594 : : /*
595 : : * The ext4_splice_branch call will free and forget any buffers
596 : : * on the new chain if there is a failure, but that risks using
597 : : * up transaction credits, especially for bitmaps where the
598 : : * credits cannot be returned. Can we handle this somehow? We
599 : : * may need to return -EAGAIN upwards in the worst case. --sct
600 : : */
601 [ # # ]: 0 : if (!err)
602 : 0 : err = ext4_splice_branch(handle, inode, map->m_lblk,
603 : : partial, indirect_blks, count);
604 [ # # ]: 0 : if (err)
605 : : goto cleanup;
606 : :
607 : 0 : map->m_flags |= EXT4_MAP_NEW;
608 : :
609 : : ext4_update_inode_fsync_trans(handle, inode, 1);
610 : : got_it:
611 : 0 : map->m_flags |= EXT4_MAP_MAPPED;
612 : 0 : map->m_pblk = le32_to_cpu(chain[depth-1].key);
613 : 0 : map->m_len = count;
614 [ # # ]: 0 : if (count > blocks_to_boundary)
615 : 0 : map->m_flags |= EXT4_MAP_BOUNDARY;
616 : 0 : err = count;
617 : : /* Clean up and exit */
618 : 0 : partial = chain + depth - 1; /* the whole chain */
619 : : cleanup:
620 [ # # ]: 0 : while (partial > chain) {
621 : : BUFFER_TRACE(partial->bh, "call brelse");
622 : 0 : brelse(partial->bh);
623 : 0 : partial--;
624 : : }
625 : : out:
626 : 0 : trace_ext4_ind_map_blocks_exit(inode, flags, map, err);
627 : 0 : return err;
628 : : }
629 : :
630 : : /*
631 : : * O_DIRECT for ext3 (or indirect map) based files
632 : : *
633 : : * If the O_DIRECT write will extend the file then add this inode to the
634 : : * orphan list. So recovery will truncate it back to the original size
635 : : * if the machine crashes during the write.
636 : : *
637 : : * If the O_DIRECT write is intantiating holes inside i_size and the machine
638 : : * crashes then stale disk data _may_ be exposed inside the file. But current
639 : : * VFS code falls back into buffered path in that case so we are safe.
640 : : */
641 : 0 : ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
642 : : const struct iovec *iov, loff_t offset,
643 : : unsigned long nr_segs)
644 : : {
645 : 101196 : struct file *file = iocb->ki_filp;
646 : 101196 : struct inode *inode = file->f_mapping->host;
647 : : struct ext4_inode_info *ei = EXT4_I(inode);
648 : : handle_t *handle;
649 : : ssize_t ret;
650 : : int orphan = 0;
651 : : size_t count = iov_length(iov, nr_segs);
652 : 101196 : int retries = 0;
653 : :
654 [ + + ]: 101196 : if (rw == WRITE) {
655 : 69663 : loff_t final_size = offset + count;
656 : :
657 [ + - ]: 69663 : if (final_size > inode->i_size) {
658 : : /* Credits for sb + inode write */
659 : : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
660 [ - + ]: 69663 : if (IS_ERR(handle)) {
661 : : ret = PTR_ERR(handle);
662 : 0 : goto out;
663 : : }
664 : 69663 : ret = ext4_orphan_add(handle, inode);
665 [ - + ]: 69663 : if (ret) {
666 : 0 : ext4_journal_stop(handle);
667 : 0 : goto out;
668 : : }
669 : : orphan = 1;
670 : 69663 : ei->i_disksize = inode->i_size;
671 : 101196 : ext4_journal_stop(handle);
672 : : }
673 : : }
674 : :
675 : : retry:
676 [ + + ][ - + ]: 132729 : if (rw == READ && ext4_should_dioread_nolock(inode)) {
677 : : /*
678 : : * Nolock dioread optimization may be dynamically disabled
679 : : * via ext4_inode_block_unlocked_dio(). Check inode's state
680 : : * while holding extra i_dio_count ref.
681 : : */
682 : 0 : atomic_inc(&inode->i_dio_count);
683 : 0 : smp_mb();
684 [ # # ]: 0 : if (unlikely(ext4_test_inode_state(inode,
685 : : EXT4_STATE_DIOREAD_LOCK))) {
686 : 0 : inode_dio_done(inode);
687 : 0 : goto locked;
688 : : }
689 : 0 : ret = __blockdev_direct_IO(rw, iocb, inode,
690 : 0 : inode->i_sb->s_bdev, iov,
691 : : offset, nr_segs,
692 : : ext4_get_block, NULL, NULL, 0);
693 : 0 : inode_dio_done(inode);
694 : : } else {
695 : : locked:
696 : : ret = blockdev_direct_IO(rw, iocb, inode, iov,
697 : : offset, nr_segs, ext4_get_block);
698 : :
699 [ + + ][ - + ]: 101196 : if (unlikely((rw & WRITE) && ret < 0)) {
700 : : loff_t isize = i_size_read(inode);
701 : 0 : loff_t end = offset + iov_length(iov, nr_segs);
702 : :
703 [ # # ]: 0 : if (end > isize)
704 : : ext4_truncate_failed_write(inode);
705 : : }
706 : : }
707 [ - + ][ # # ]: 101196 : if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
708 : : goto retry;
709 : :
710 [ + + ]: 101196 : if (orphan) {
711 : : int err;
712 : :
713 : : /* Credits for sb + inode write */
714 : : handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
715 [ - + ]: 69663 : if (IS_ERR(handle)) {
716 : : /* This is really bad luck. We've written the data
717 : : * but cannot extend i_size. Bail out and pretend
718 : : * the write failed... */
719 : : ret = PTR_ERR(handle);
720 [ # # ]: 0 : if (inode->i_nlink)
721 : 0 : ext4_orphan_del(NULL, inode);
722 : :
723 : : goto out;
724 : : }
725 [ + - ]: 69663 : if (inode->i_nlink)
726 : 69663 : ext4_orphan_del(handle, inode);
727 [ + - ]: 69663 : if (ret > 0) {
728 : 69663 : loff_t end = offset + ret;
729 [ + - ]: 69663 : if (end > inode->i_size) {
730 : 69663 : ei->i_disksize = end;
731 : : i_size_write(inode, end);
732 : : /*
733 : : * We're going to return a positive `ret'
734 : : * here due to non-zero-length I/O, so there's
735 : : * no way of reporting error returns from
736 : : * ext4_mark_inode_dirty() to userspace. So
737 : : * ignore it.
738 : : */
739 : 69663 : ext4_mark_inode_dirty(handle, inode);
740 : : }
741 : : }
742 : 69663 : err = ext4_journal_stop(handle);
743 [ - + ]: 69663 : if (ret == 0)
744 : : ret = err;
745 : : }
746 : : out:
747 : 101196 : return ret;
748 : : }
749 : :
750 : : /*
751 : : * Calculate the number of metadata blocks need to reserve
752 : : * to allocate a new block at @lblocks for non extent file based file
753 : : */
754 : 0 : int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
755 : : {
756 : : struct ext4_inode_info *ei = EXT4_I(inode);
757 : 0 : sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
758 : : int blk_bits;
759 : :
760 [ # # ]: 0 : if (lblock < EXT4_NDIR_BLOCKS)
761 : : return 0;
762 : :
763 : 0 : lblock -= EXT4_NDIR_BLOCKS;
764 : :
765 [ # # ][ # # ]: 0 : if (ei->i_da_metadata_calc_len &&
766 : 0 : (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
767 : 0 : ei->i_da_metadata_calc_len++;
768 : 0 : return 0;
769 : : }
770 : 0 : ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
771 : 0 : ei->i_da_metadata_calc_len = 1;
772 [ # # ][ # # ]: 0 : blk_bits = order_base_2(lblock);
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773 : 0 : return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
774 : : }
775 : :
776 : : /*
777 : : * Calculate number of indirect blocks touched by mapping @nrblocks logically
778 : : * contiguous blocks
779 : : */
780 : 0 : int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
781 : : {
782 : : /*
783 : : * With N contiguous data blocks, we need at most
784 : : * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
785 : : * 2 dindirect blocks, and 1 tindirect block
786 : : */
787 : 0 : return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
788 : : }
789 : :
790 : : /*
791 : : * Truncate transactions can be complex and absolutely huge. So we need to
792 : : * be able to restart the transaction at a conventient checkpoint to make
793 : : * sure we don't overflow the journal.
794 : : *
795 : : * Try to extend this transaction for the purposes of truncation. If
796 : : * extend fails, we need to propagate the failure up and restart the
797 : : * transaction in the top-level truncate loop. --sct
798 : : *
799 : : * Returns 0 if we managed to create more room. If we can't create more
800 : : * room, and the transaction must be restarted we return 1.
801 : : */
802 : 0 : static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
803 : : {
804 [ # # ]: 0 : if (!ext4_handle_valid(handle))
805 : : return 0;
806 [ # # ]: 0 : if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
807 : : return 0;
808 [ # # ]: 0 : if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode)))
809 : : return 0;
810 : : return 1;
811 : : }
812 : :
813 : : /*
814 : : * Probably it should be a library function... search for first non-zero word
815 : : * or memcmp with zero_page, whatever is better for particular architecture.
816 : : * Linus?
817 : : */
818 : : static inline int all_zeroes(__le32 *p, __le32 *q)
819 : : {
820 [ # # ][ # # ]: 0 : while (p < q)
821 [ # # ][ # # ]: 0 : if (*p++)
822 : : return 0;
823 : : return 1;
824 : : }
825 : :
826 : : /**
827 : : * ext4_find_shared - find the indirect blocks for partial truncation.
828 : : * @inode: inode in question
829 : : * @depth: depth of the affected branch
830 : : * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
831 : : * @chain: place to store the pointers to partial indirect blocks
832 : : * @top: place to the (detached) top of branch
833 : : *
834 : : * This is a helper function used by ext4_truncate().
835 : : *
836 : : * When we do truncate() we may have to clean the ends of several
837 : : * indirect blocks but leave the blocks themselves alive. Block is
838 : : * partially truncated if some data below the new i_size is referred
839 : : * from it (and it is on the path to the first completely truncated
840 : : * data block, indeed). We have to free the top of that path along
841 : : * with everything to the right of the path. Since no allocation
842 : : * past the truncation point is possible until ext4_truncate()
843 : : * finishes, we may safely do the latter, but top of branch may
844 : : * require special attention - pageout below the truncation point
845 : : * might try to populate it.
846 : : *
847 : : * We atomically detach the top of branch from the tree, store the
848 : : * block number of its root in *@top, pointers to buffer_heads of
849 : : * partially truncated blocks - in @chain[].bh and pointers to
850 : : * their last elements that should not be removed - in
851 : : * @chain[].p. Return value is the pointer to last filled element
852 : : * of @chain.
853 : : *
854 : : * The work left to caller to do the actual freeing of subtrees:
855 : : * a) free the subtree starting from *@top
856 : : * b) free the subtrees whose roots are stored in
857 : : * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
858 : : * c) free the subtrees growing from the inode past the @chain[0].
859 : : * (no partially truncated stuff there). */
860 : :
861 : 0 : static Indirect *ext4_find_shared(struct inode *inode, int depth,
862 : : ext4_lblk_t offsets[4], Indirect chain[4],
863 : : __le32 *top)
864 : : {
865 : : Indirect *partial, *p;
866 : : int k, err;
867 : :
868 : 0 : *top = 0;
869 : : /* Make k index the deepest non-null offset + 1 */
870 [ # # ][ # # ]: 0 : for (k = depth; k > 1 && !offsets[k-1]; k--)
871 : : ;
872 : 0 : partial = ext4_get_branch(inode, k, offsets, chain, &err);
873 : : /* Writer: pointers */
874 [ # # ]: 0 : if (!partial)
875 : 0 : partial = chain + k-1;
876 : : /*
877 : : * If the branch acquired continuation since we've looked at it -
878 : : * fine, it should all survive and (new) top doesn't belong to us.
879 : : */
880 [ # # ][ # # ]: 0 : if (!partial->key && *partial->p)
881 : : /* Writer: end */
882 : : goto no_top;
883 [ # # ][ # # ]: 0 : for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
884 : : ;
885 : : /*
886 : : * OK, we've found the last block that must survive. The rest of our
887 : : * branch should be detached before unlocking. However, if that rest
888 : : * of branch is all ours and does not grow immediately from the inode
889 : : * it's easier to cheat and just decrement partial->p.
890 : : */
891 [ # # ][ # # ]: 0 : if (p == chain + k - 1 && p > chain) {
892 : 0 : p->p--;
893 : : } else {
894 : 0 : *top = *p->p;
895 : : /* Nope, don't do this in ext4. Must leave the tree intact */
896 : : #if 0
897 : : *p->p = 0;
898 : : #endif
899 : : }
900 : : /* Writer: end */
901 : :
902 [ # # ]: 0 : while (partial > p) {
903 : 0 : brelse(partial->bh);
904 : 0 : partial--;
905 : : }
906 : : no_top:
907 : 0 : return partial;
908 : : }
909 : :
910 : : /*
911 : : * Zero a number of block pointers in either an inode or an indirect block.
912 : : * If we restart the transaction we must again get write access to the
913 : : * indirect block for further modification.
914 : : *
915 : : * We release `count' blocks on disk, but (last - first) may be greater
916 : : * than `count' because there can be holes in there.
917 : : *
918 : : * Return 0 on success, 1 on invalid block range
919 : : * and < 0 on fatal error.
920 : : */
921 : 0 : static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
922 : : struct buffer_head *bh,
923 : : ext4_fsblk_t block_to_free,
924 : : unsigned long count, __le32 *first,
925 : : __le32 *last)
926 : : {
927 : : __le32 *p;
928 : : int flags = EXT4_FREE_BLOCKS_VALIDATED;
929 : : int err;
930 : :
931 [ # # ]: 0 : if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
932 : : flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
933 [ # # ]: 0 : else if (ext4_should_journal_data(inode))
934 : : flags |= EXT4_FREE_BLOCKS_FORGET;
935 : :
936 [ # # ]: 0 : if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
937 : : count)) {
938 : 0 : EXT4_ERROR_INODE(inode, "attempt to clear invalid "
939 : : "blocks %llu len %lu",
940 : : (unsigned long long) block_to_free, count);
941 : 0 : return 1;
942 : : }
943 : :
944 [ # # ]: 0 : if (try_to_extend_transaction(handle, inode)) {
945 [ # # ]: 0 : if (bh) {
946 : : BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
947 : 0 : err = ext4_handle_dirty_metadata(handle, inode, bh);
948 [ # # ]: 0 : if (unlikely(err))
949 : : goto out_err;
950 : : }
951 : 0 : err = ext4_mark_inode_dirty(handle, inode);
952 [ # # ]: 0 : if (unlikely(err))
953 : : goto out_err;
954 : 0 : err = ext4_truncate_restart_trans(handle, inode,
955 : : ext4_blocks_for_truncate(inode));
956 [ # # ]: 0 : if (unlikely(err))
957 : : goto out_err;
958 [ # # ]: 0 : if (bh) {
959 : : BUFFER_TRACE(bh, "retaking write access");
960 : 0 : err = ext4_journal_get_write_access(handle, bh);
961 [ # # ]: 0 : if (unlikely(err))
962 : : goto out_err;
963 : : }
964 : : }
965 : :
966 [ # # ]: 0 : for (p = first; p < last; p++)
967 : 0 : *p = 0;
968 : :
969 : 0 : ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
970 : 0 : return 0;
971 : : out_err:
972 [ # # ]: 0 : ext4_std_error(inode->i_sb, err);
973 : 0 : return err;
974 : : }
975 : :
976 : : /**
977 : : * ext4_free_data - free a list of data blocks
978 : : * @handle: handle for this transaction
979 : : * @inode: inode we are dealing with
980 : : * @this_bh: indirect buffer_head which contains *@first and *@last
981 : : * @first: array of block numbers
982 : : * @last: points immediately past the end of array
983 : : *
984 : : * We are freeing all blocks referred from that array (numbers are stored as
985 : : * little-endian 32-bit) and updating @inode->i_blocks appropriately.
986 : : *
987 : : * We accumulate contiguous runs of blocks to free. Conveniently, if these
988 : : * blocks are contiguous then releasing them at one time will only affect one
989 : : * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
990 : : * actually use a lot of journal space.
991 : : *
992 : : * @this_bh will be %NULL if @first and @last point into the inode's direct
993 : : * block pointers.
994 : : */
995 : 0 : static void ext4_free_data(handle_t *handle, struct inode *inode,
996 : 0 : struct buffer_head *this_bh,
997 : : __le32 *first, __le32 *last)
998 : : {
999 : : ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
1000 : : unsigned long count = 0; /* Number of blocks in the run */
1001 : : __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
1002 : : corresponding to
1003 : : block_to_free */
1004 : : ext4_fsblk_t nr; /* Current block # */
1005 : : __le32 *p; /* Pointer into inode/ind
1006 : : for current block */
1007 : : int err = 0;
1008 : :
1009 [ # # ]: 0 : if (this_bh) { /* For indirect block */
1010 : : BUFFER_TRACE(this_bh, "get_write_access");
1011 : 0 : err = ext4_journal_get_write_access(handle, this_bh);
1012 : : /* Important: if we can't update the indirect pointers
1013 : : * to the blocks, we can't free them. */
1014 [ # # ]: 0 : if (err)
1015 : : return;
1016 : : }
1017 : :
1018 [ # # ]: 0 : for (p = first; p < last; p++) {
1019 : 0 : nr = le32_to_cpu(*p);
1020 [ # # ]: 0 : if (nr) {
1021 : : /* accumulate blocks to free if they're contiguous */
1022 [ # # ]: 0 : if (count == 0) {
1023 : : block_to_free = nr;
1024 : : block_to_free_p = p;
1025 : : count = 1;
1026 [ # # ]: 0 : } else if (nr == block_to_free + count) {
1027 : 0 : count++;
1028 : : } else {
1029 : 0 : err = ext4_clear_blocks(handle, inode, this_bh,
1030 : : block_to_free, count,
1031 : : block_to_free_p, p);
1032 [ # # ]: 0 : if (err)
1033 : : break;
1034 : : block_to_free = nr;
1035 : : block_to_free_p = p;
1036 : : count = 1;
1037 : : }
1038 : : }
1039 : : }
1040 : :
1041 [ # # ]: 0 : if (!err && count > 0)
1042 : 0 : err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
1043 : : count, block_to_free_p, p);
1044 [ # # ]: 0 : if (err < 0)
1045 : : /* fatal error */
1046 : : return;
1047 : :
1048 [ # # ]: 0 : if (this_bh) {
1049 : : BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
1050 : :
1051 : : /*
1052 : : * The buffer head should have an attached journal head at this
1053 : : * point. However, if the data is corrupted and an indirect
1054 : : * block pointed to itself, it would have been detached when
1055 : : * the block was cleared. Check for this instead of OOPSing.
1056 : : */
1057 [ # # ][ # # ]: 0 : if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
1058 : 0 : ext4_handle_dirty_metadata(handle, inode, this_bh);
1059 : : else
1060 : 0 : EXT4_ERROR_INODE(inode,
1061 : : "circular indirect block detected at "
1062 : : "block %llu",
1063 : : (unsigned long long) this_bh->b_blocknr);
1064 : : }
1065 : : }
1066 : :
1067 : : /**
1068 : : * ext4_free_branches - free an array of branches
1069 : : * @handle: JBD handle for this transaction
1070 : : * @inode: inode we are dealing with
1071 : : * @parent_bh: the buffer_head which contains *@first and *@last
1072 : : * @first: array of block numbers
1073 : : * @last: pointer immediately past the end of array
1074 : : * @depth: depth of the branches to free
1075 : : *
1076 : : * We are freeing all blocks referred from these branches (numbers are
1077 : : * stored as little-endian 32-bit) and updating @inode->i_blocks
1078 : : * appropriately.
1079 : : */
1080 : 0 : static void ext4_free_branches(handle_t *handle, struct inode *inode,
1081 : : struct buffer_head *parent_bh,
1082 : : __le32 *first, __le32 *last, int depth)
1083 : : {
1084 : : ext4_fsblk_t nr;
1085 : : __le32 *p;
1086 : :
1087 [ # # ]: 0 : if (ext4_handle_is_aborted(handle))
1088 : : return;
1089 : :
1090 [ # # ]: 0 : if (depth--) {
1091 : : struct buffer_head *bh;
1092 : 0 : int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1093 : : p = last;
1094 [ # # ]: 0 : while (--p >= first) {
1095 : 0 : nr = le32_to_cpu(*p);
1096 [ # # ]: 0 : if (!nr)
1097 : 0 : continue; /* A hole */
1098 : :
1099 [ # # ]: 0 : if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
1100 : : nr, 1)) {
1101 : 0 : EXT4_ERROR_INODE(inode,
1102 : : "invalid indirect mapped "
1103 : : "block %lu (level %d)",
1104 : : (unsigned long) nr, depth);
1105 : 0 : break;
1106 : : }
1107 : :
1108 : : /* Go read the buffer for the next level down */
1109 : 0 : bh = sb_bread(inode->i_sb, nr);
1110 : :
1111 : : /*
1112 : : * A read failure? Report error and clear slot
1113 : : * (should be rare).
1114 : : */
1115 [ # # ]: 0 : if (!bh) {
1116 : 0 : EXT4_ERROR_INODE_BLOCK(inode, nr,
1117 : : "Read failure");
1118 : 0 : continue;
1119 : : }
1120 : :
1121 : : /* This zaps the entire block. Bottom up. */
1122 : : BUFFER_TRACE(bh, "free child branches");
1123 : 0 : ext4_free_branches(handle, inode, bh,
1124 : : (__le32 *) bh->b_data,
1125 : 0 : (__le32 *) bh->b_data + addr_per_block,
1126 : : depth);
1127 : : brelse(bh);
1128 : :
1129 : : /*
1130 : : * Everything below this this pointer has been
1131 : : * released. Now let this top-of-subtree go.
1132 : : *
1133 : : * We want the freeing of this indirect block to be
1134 : : * atomic in the journal with the updating of the
1135 : : * bitmap block which owns it. So make some room in
1136 : : * the journal.
1137 : : *
1138 : : * We zero the parent pointer *after* freeing its
1139 : : * pointee in the bitmaps, so if extend_transaction()
1140 : : * for some reason fails to put the bitmap changes and
1141 : : * the release into the same transaction, recovery
1142 : : * will merely complain about releasing a free block,
1143 : : * rather than leaking blocks.
1144 : : */
1145 [ # # ]: 0 : if (ext4_handle_is_aborted(handle))
1146 : : return;
1147 [ # # ]: 0 : if (try_to_extend_transaction(handle, inode)) {
1148 : 0 : ext4_mark_inode_dirty(handle, inode);
1149 : 0 : ext4_truncate_restart_trans(handle, inode,
1150 : : ext4_blocks_for_truncate(inode));
1151 : : }
1152 : :
1153 : : /*
1154 : : * The forget flag here is critical because if
1155 : : * we are journaling (and not doing data
1156 : : * journaling), we have to make sure a revoke
1157 : : * record is written to prevent the journal
1158 : : * replay from overwriting the (former)
1159 : : * indirect block if it gets reallocated as a
1160 : : * data block. This must happen in the same
1161 : : * transaction where the data blocks are
1162 : : * actually freed.
1163 : : */
1164 : 0 : ext4_free_blocks(handle, inode, NULL, nr, 1,
1165 : : EXT4_FREE_BLOCKS_METADATA|
1166 : : EXT4_FREE_BLOCKS_FORGET);
1167 : :
1168 [ # # ]: 0 : if (parent_bh) {
1169 : : /*
1170 : : * The block which we have just freed is
1171 : : * pointed to by an indirect block: journal it
1172 : : */
1173 : : BUFFER_TRACE(parent_bh, "get_write_access");
1174 [ # # ]: 0 : if (!ext4_journal_get_write_access(handle,
1175 : : parent_bh)){
1176 : 0 : *p = 0;
1177 : : BUFFER_TRACE(parent_bh,
1178 : : "call ext4_handle_dirty_metadata");
1179 : 0 : ext4_handle_dirty_metadata(handle,
1180 : : inode,
1181 : : parent_bh);
1182 : : }
1183 : : }
1184 : : }
1185 : : } else {
1186 : : /* We have reached the bottom of the tree. */
1187 : : BUFFER_TRACE(parent_bh, "free data blocks");
1188 : 0 : ext4_free_data(handle, inode, parent_bh, first, last);
1189 : : }
1190 : : }
1191 : :
1192 : 0 : void ext4_ind_truncate(handle_t *handle, struct inode *inode)
1193 : : {
1194 : : struct ext4_inode_info *ei = EXT4_I(inode);
1195 : 0 : __le32 *i_data = ei->i_data;
1196 : 0 : int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1197 : : ext4_lblk_t offsets[4];
1198 : : Indirect chain[4];
1199 : : Indirect *partial;
1200 : 0 : __le32 nr = 0;
1201 : : int n = 0;
1202 : : ext4_lblk_t last_block, max_block;
1203 : : unsigned blocksize = inode->i_sb->s_blocksize;
1204 : :
1205 : 0 : last_block = (inode->i_size + blocksize-1)
1206 : 0 : >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
1207 : 0 : max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
1208 : 0 : >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
1209 : :
1210 [ # # ]: 0 : if (last_block != max_block) {
1211 : 0 : n = ext4_block_to_path(inode, last_block, offsets, NULL);
1212 [ # # ]: 0 : if (n == 0)
1213 : 0 : return;
1214 : : }
1215 : :
1216 : 0 : ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
1217 : :
1218 : : /*
1219 : : * The orphan list entry will now protect us from any crash which
1220 : : * occurs before the truncate completes, so it is now safe to propagate
1221 : : * the new, shorter inode size (held for now in i_size) into the
1222 : : * on-disk inode. We do this via i_disksize, which is the value which
1223 : : * ext4 *really* writes onto the disk inode.
1224 : : */
1225 : 0 : ei->i_disksize = inode->i_size;
1226 : :
1227 [ # # ]: 0 : if (last_block == max_block) {
1228 : : /*
1229 : : * It is unnecessary to free any data blocks if last_block is
1230 : : * equal to the indirect block limit.
1231 : : */
1232 : : return;
1233 [ # # ]: 0 : } else if (n == 1) { /* direct blocks */
1234 : 0 : ext4_free_data(handle, inode, NULL, i_data+offsets[0],
1235 : : i_data + EXT4_NDIR_BLOCKS);
1236 : 0 : goto do_indirects;
1237 : : }
1238 : :
1239 : 0 : partial = ext4_find_shared(inode, n, offsets, chain, &nr);
1240 : : /* Kill the top of shared branch (not detached) */
1241 [ # # ]: 0 : if (nr) {
1242 [ # # ]: 0 : if (partial == chain) {
1243 : : /* Shared branch grows from the inode */
1244 : 0 : ext4_free_branches(handle, inode, NULL,
1245 : 0 : &nr, &nr+1, (chain+n-1) - partial);
1246 : 0 : *partial->p = 0;
1247 : : /*
1248 : : * We mark the inode dirty prior to restart,
1249 : : * and prior to stop. No need for it here.
1250 : : */
1251 : : } else {
1252 : : /* Shared branch grows from an indirect block */
1253 : : BUFFER_TRACE(partial->bh, "get_write_access");
1254 : 0 : ext4_free_branches(handle, inode, partial->bh,
1255 : : partial->p,
1256 : 0 : partial->p+1, (chain+n-1) - partial);
1257 : : }
1258 : : }
1259 : : /* Clear the ends of indirect blocks on the shared branch */
1260 [ # # ]: 0 : while (partial > chain) {
1261 : 0 : ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
1262 : 0 : (__le32*)partial->bh->b_data+addr_per_block,
1263 : 0 : (chain+n-1) - partial);
1264 : : BUFFER_TRACE(partial->bh, "call brelse");
1265 : 0 : brelse(partial->bh);
1266 : 0 : partial--;
1267 : : }
1268 : : do_indirects:
1269 : : /* Kill the remaining (whole) subtrees */
1270 [ # # # # ]: 0 : switch (offsets[0]) {
1271 : : default:
1272 : 0 : nr = i_data[EXT4_IND_BLOCK];
1273 [ # # ]: 0 : if (nr) {
1274 : 0 : ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
1275 : 0 : i_data[EXT4_IND_BLOCK] = 0;
1276 : : }
1277 : : case EXT4_IND_BLOCK:
1278 : 0 : nr = i_data[EXT4_DIND_BLOCK];
1279 [ # # ]: 0 : if (nr) {
1280 : 0 : ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
1281 : 0 : i_data[EXT4_DIND_BLOCK] = 0;
1282 : : }
1283 : : case EXT4_DIND_BLOCK:
1284 : 0 : nr = i_data[EXT4_TIND_BLOCK];
1285 [ # # ]: 0 : if (nr) {
1286 : 0 : ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
1287 : 0 : i_data[EXT4_TIND_BLOCK] = 0;
1288 : : }
1289 : : case EXT4_TIND_BLOCK:
1290 : : ;
1291 : : }
1292 : : }
1293 : :
1294 : 0 : static int free_hole_blocks(handle_t *handle, struct inode *inode,
1295 : : struct buffer_head *parent_bh, __le32 *i_data,
1296 : : int level, ext4_lblk_t first,
1297 : : ext4_lblk_t count, int max)
1298 : : {
1299 : : struct buffer_head *bh = NULL;
1300 : 0 : int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1301 : : int ret = 0;
1302 : : int i, inc;
1303 : : ext4_lblk_t offset;
1304 : : __le32 blk;
1305 : :
1306 : 0 : inc = 1 << ((EXT4_BLOCK_SIZE_BITS(inode->i_sb) - 2) * level);
1307 [ # # ]: 0 : for (i = 0, offset = 0; i < max; i++, i_data++, offset += inc) {
1308 [ # # ]: 0 : if (offset >= count + first)
1309 : : break;
1310 [ # # ][ # # ]: 0 : if (*i_data == 0 || (offset + inc) <= first)
1311 : 0 : continue;
1312 : 0 : blk = *i_data;
1313 [ # # ]: 0 : if (level > 0) {
1314 : : ext4_lblk_t first2;
1315 : 0 : bh = sb_bread(inode->i_sb, le32_to_cpu(blk));
1316 [ # # ]: 0 : if (!bh) {
1317 : 0 : EXT4_ERROR_INODE_BLOCK(inode, le32_to_cpu(blk),
1318 : : "Read failure");
1319 : 0 : return -EIO;
1320 : : }
1321 [ # # ]: 0 : first2 = (first > offset) ? first - offset : 0;
1322 : 0 : ret = free_hole_blocks(handle, inode, bh,
1323 : 0 : (__le32 *)bh->b_data, level - 1,
1324 : : first2, count - offset,
1325 : 0 : inode->i_sb->s_blocksize >> 2);
1326 [ # # ]: 0 : if (ret) {
1327 : : brelse(bh);
1328 : : goto err;
1329 : : }
1330 : : }
1331 [ # # ][ # # ]: 0 : if (level == 0 ||
1332 [ # # ]: 0 : (bh && all_zeroes((__le32 *)bh->b_data,
1333 : 0 : (__le32 *)bh->b_data + addr_per_block))) {
1334 : 0 : ext4_free_data(handle, inode, parent_bh, &blk, &blk+1);
1335 : 0 : *i_data = 0;
1336 : : }
1337 : : brelse(bh);
1338 : : bh = NULL;
1339 : : }
1340 : :
1341 : : err:
1342 : 0 : return ret;
1343 : : }
1344 : :
1345 : 0 : int ext4_free_hole_blocks(handle_t *handle, struct inode *inode,
1346 : : ext4_lblk_t first, ext4_lblk_t stop)
1347 : : {
1348 : 0 : int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1349 : : int level, ret = 0;
1350 : : int num = EXT4_NDIR_BLOCKS;
1351 : : ext4_lblk_t count, max = EXT4_NDIR_BLOCKS;
1352 : 0 : __le32 *i_data = EXT4_I(inode)->i_data;
1353 : :
1354 : 0 : count = stop - first;
1355 [ # # ]: 0 : for (level = 0; level < 4; level++, max *= addr_per_block) {
1356 [ # # ]: 0 : if (first < max) {
1357 : 0 : ret = free_hole_blocks(handle, inode, NULL, i_data,
1358 : : level, first, count, num);
1359 [ # # ]: 0 : if (ret)
1360 : : goto err;
1361 [ # # ]: 0 : if (count > max - first)
1362 : 0 : count -= max - first;
1363 : : else
1364 : : break;
1365 : : first = 0;
1366 : : } else {
1367 : 0 : first -= max;
1368 : : }
1369 : 0 : i_data += num;
1370 [ # # ]: 0 : if (level == 0) {
1371 : : num = 1;
1372 : : max = 1;
1373 : : }
1374 : : }
1375 : :
1376 : : err:
1377 : 0 : return ret;
1378 : : }
1379 : :
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