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1 | /* |
2 | * This file is part of UBIFS. | |
3 | * | |
4 | * Copyright (C) 2006-2008 Nokia Corporation. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published by | |
8 | * the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
17 | * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | * | |
19 | * Authors: Adrian Hunter | |
20 | * Artem Bityutskiy (Битюцкий Артём) | |
21 | */ | |
22 | ||
23 | /* | |
24 | * This file implements the budgeting sub-system which is responsible for UBIFS | |
25 | * space management. | |
26 | * | |
27 | * Factors such as compression, wasted space at the ends of LEBs, space in other | |
28 | * journal heads, the effect of updates on the index, and so on, make it | |
29 | * impossible to accurately predict the amount of space needed. Consequently | |
30 | * approximations are used. | |
31 | */ | |
32 | ||
33 | #include "ubifs.h" | |
34 | #include <linux/writeback.h> | |
35 | #include <asm/div64.h> | |
36 | ||
37 | /* | |
38 | * When pessimistic budget calculations say that there is no enough space, | |
39 | * UBIFS starts writing back dirty inodes and pages, doing garbage collection, | |
40 | * or committing. The below constants define maximum number of times UBIFS | |
41 | * repeats the operations. | |
42 | */ | |
43 | #define MAX_SHRINK_RETRIES 8 | |
44 | #define MAX_GC_RETRIES 4 | |
45 | #define MAX_CMT_RETRIES 2 | |
46 | #define MAX_NOSPC_RETRIES 1 | |
47 | ||
48 | /* | |
49 | * The below constant defines amount of dirty pages which should be written | |
50 | * back at when trying to shrink the liability. | |
51 | */ | |
52 | #define NR_TO_WRITE 16 | |
53 | ||
54 | /** | |
55 | * struct retries_info - information about re-tries while making free space. | |
56 | * @prev_liability: previous liability | |
57 | * @shrink_cnt: how many times the liability was shrinked | |
58 | * @shrink_retries: count of liability shrink re-tries (increased when | |
59 | * liability does not shrink) | |
60 | * @try_gc: GC should be tried first | |
61 | * @gc_retries: how many times GC was run | |
62 | * @cmt_retries: how many times commit has been done | |
63 | * @nospc_retries: how many times GC returned %-ENOSPC | |
64 | * | |
65 | * Since we consider budgeting to be the fast-path, and this structure has to | |
66 | * be allocated on stack and zeroed out, we make it smaller using bit-fields. | |
67 | */ | |
68 | struct retries_info { | |
69 | long long prev_liability; | |
70 | unsigned int shrink_cnt; | |
71 | unsigned int shrink_retries:5; | |
72 | unsigned int try_gc:1; | |
73 | unsigned int gc_retries:4; | |
74 | unsigned int cmt_retries:3; | |
75 | unsigned int nospc_retries:1; | |
76 | }; | |
77 | ||
78 | /** | |
79 | * shrink_liability - write-back some dirty pages/inodes. | |
80 | * @c: UBIFS file-system description object | |
81 | * @nr_to_write: how many dirty pages to write-back | |
82 | * | |
83 | * This function shrinks UBIFS liability by means of writing back some amount | |
84 | * of dirty inodes and their pages. Returns the amount of pages which were | |
85 | * written back. The returned value does not include dirty inodes which were | |
86 | * synchronized. | |
87 | * | |
88 | * Note, this function synchronizes even VFS inodes which are locked | |
89 | * (@i_mutex) by the caller of the budgeting function, because write-back does | |
90 | * not touch @i_mutex. | |
91 | */ | |
92 | static int shrink_liability(struct ubifs_info *c, int nr_to_write) | |
93 | { | |
94 | int nr_written; | |
95 | struct writeback_control wbc = { | |
96 | .sync_mode = WB_SYNC_NONE, | |
97 | .range_end = LLONG_MAX, | |
98 | .nr_to_write = nr_to_write, | |
99 | }; | |
100 | ||
101 | generic_sync_sb_inodes(c->vfs_sb, &wbc); | |
102 | nr_written = nr_to_write - wbc.nr_to_write; | |
103 | ||
104 | if (!nr_written) { | |
105 | /* | |
106 | * Re-try again but wait on pages/inodes which are being | |
107 | * written-back concurrently (e.g., by pdflush). | |
108 | */ | |
109 | memset(&wbc, 0, sizeof(struct writeback_control)); | |
110 | wbc.sync_mode = WB_SYNC_ALL; | |
111 | wbc.range_end = LLONG_MAX; | |
112 | wbc.nr_to_write = nr_to_write; | |
113 | generic_sync_sb_inodes(c->vfs_sb, &wbc); | |
114 | nr_written = nr_to_write - wbc.nr_to_write; | |
115 | } | |
116 | ||
117 | dbg_budg("%d pages were written back", nr_written); | |
118 | return nr_written; | |
119 | } | |
120 | ||
121 | ||
122 | /** | |
123 | * run_gc - run garbage collector. | |
124 | * @c: UBIFS file-system description object | |
125 | * | |
126 | * This function runs garbage collector to make some more free space. Returns | |
127 | * zero if a free LEB has been produced, %-EAGAIN if commit is required, and a | |
128 | * negative error code in case of failure. | |
129 | */ | |
130 | static int run_gc(struct ubifs_info *c) | |
131 | { | |
132 | int err, lnum; | |
133 | ||
134 | /* Make some free space by garbage-collecting dirty space */ | |
135 | down_read(&c->commit_sem); | |
136 | lnum = ubifs_garbage_collect(c, 1); | |
137 | up_read(&c->commit_sem); | |
138 | if (lnum < 0) | |
139 | return lnum; | |
140 | ||
141 | /* GC freed one LEB, return it to lprops */ | |
142 | dbg_budg("GC freed LEB %d", lnum); | |
143 | err = ubifs_return_leb(c, lnum); | |
144 | if (err) | |
145 | return err; | |
146 | return 0; | |
147 | } | |
148 | ||
149 | /** | |
150 | * make_free_space - make more free space on the file-system. | |
151 | * @c: UBIFS file-system description object | |
152 | * @ri: information about previous invocations of this function | |
153 | * | |
154 | * This function is called when an operation cannot be budgeted because there | |
155 | * is supposedly no free space. But in most cases there is some free space: | |
156 | * o budgeting is pessimistic, so it always budgets more then it is actually | |
157 | * needed, so shrinking the liability is one way to make free space - the | |
158 | * cached data will take less space then it was budgeted for; | |
159 | * o GC may turn some dark space into free space (budgeting treats dark space | |
160 | * as not available); | |
161 | * o commit may free some LEB, i.e., turn freeable LEBs into free LEBs. | |
162 | * | |
163 | * So this function tries to do the above. Returns %-EAGAIN if some free space | |
164 | * was presumably made and the caller has to re-try budgeting the operation. | |
165 | * Returns %-ENOSPC if it couldn't do more free space, and other negative error | |
166 | * codes on failures. | |
167 | */ | |
168 | static int make_free_space(struct ubifs_info *c, struct retries_info *ri) | |
169 | { | |
170 | int err; | |
171 | ||
172 | /* | |
173 | * If we have some dirty pages and inodes (liability), try to write | |
174 | * them back unless this was tried too many times without effect | |
175 | * already. | |
176 | */ | |
177 | if (ri->shrink_retries < MAX_SHRINK_RETRIES && !ri->try_gc) { | |
178 | long long liability; | |
179 | ||
180 | spin_lock(&c->space_lock); | |
181 | liability = c->budg_idx_growth + c->budg_data_growth + | |
182 | c->budg_dd_growth; | |
183 | spin_unlock(&c->space_lock); | |
184 | ||
185 | if (ri->prev_liability >= liability) { | |
186 | /* Liability does not shrink, next time try GC then */ | |
187 | ri->shrink_retries += 1; | |
188 | if (ri->gc_retries < MAX_GC_RETRIES) | |
189 | ri->try_gc = 1; | |
190 | dbg_budg("liability did not shrink: retries %d of %d", | |
191 | ri->shrink_retries, MAX_SHRINK_RETRIES); | |
192 | } | |
193 | ||
194 | dbg_budg("force write-back (count %d)", ri->shrink_cnt); | |
195 | shrink_liability(c, NR_TO_WRITE + ri->shrink_cnt); | |
196 | ||
197 | ri->prev_liability = liability; | |
198 | ri->shrink_cnt += 1; | |
199 | return -EAGAIN; | |
200 | } | |
201 | ||
202 | /* | |
203 | * Try to run garbage collector unless it was already tried too many | |
204 | * times. | |
205 | */ | |
206 | if (ri->gc_retries < MAX_GC_RETRIES) { | |
207 | ri->gc_retries += 1; | |
208 | dbg_budg("run GC, retries %d of %d", | |
209 | ri->gc_retries, MAX_GC_RETRIES); | |
210 | ||
211 | ri->try_gc = 0; | |
212 | err = run_gc(c); | |
213 | if (!err) | |
214 | return -EAGAIN; | |
215 | ||
216 | if (err == -EAGAIN) { | |
217 | dbg_budg("GC asked to commit"); | |
218 | err = ubifs_run_commit(c); | |
219 | if (err) | |
220 | return err; | |
221 | return -EAGAIN; | |
222 | } | |
223 | ||
224 | if (err != -ENOSPC) | |
225 | return err; | |
226 | ||
227 | /* | |
228 | * GC could not make any progress. If this is the first time, | |
229 | * then it makes sense to try to commit, because it might make | |
230 | * some dirty space. | |
231 | */ | |
232 | dbg_budg("GC returned -ENOSPC, retries %d", | |
233 | ri->nospc_retries); | |
234 | if (ri->nospc_retries >= MAX_NOSPC_RETRIES) | |
235 | return err; | |
236 | ri->nospc_retries += 1; | |
237 | } | |
238 | ||
239 | /* Neither GC nor write-back helped, try to commit */ | |
240 | if (ri->cmt_retries < MAX_CMT_RETRIES) { | |
241 | ri->cmt_retries += 1; | |
242 | dbg_budg("run commit, retries %d of %d", | |
243 | ri->cmt_retries, MAX_CMT_RETRIES); | |
244 | err = ubifs_run_commit(c); | |
245 | if (err) | |
246 | return err; | |
247 | return -EAGAIN; | |
248 | } | |
249 | return -ENOSPC; | |
250 | } | |
251 | ||
252 | /** | |
253 | * ubifs_calc_min_idx_lebs - calculate amount of eraseblocks for the index. | |
254 | * @c: UBIFS file-system description object | |
255 | * | |
256 | * This function calculates and returns the number of eraseblocks which should | |
257 | * be kept for index usage. | |
258 | */ | |
259 | int ubifs_calc_min_idx_lebs(struct ubifs_info *c) | |
260 | { | |
261 | int ret; | |
262 | uint64_t idx_size; | |
263 | ||
264 | idx_size = c->old_idx_sz + c->budg_idx_growth + c->budg_uncommitted_idx; | |
265 | ||
266 | /* And make sure we have twice the index size of space reserved */ | |
267 | idx_size <<= 1; | |
268 | ||
269 | /* | |
270 | * We do not maintain 'old_idx_size' as 'old_idx_lebs'/'old_idx_bytes' | |
271 | * pair, nor similarly the two variables for the new index size, so we | |
272 | * have to do this costly 64-bit division on fast-path. | |
273 | */ | |
274 | if (do_div(idx_size, c->leb_size - c->max_idx_node_sz)) | |
275 | ret = idx_size + 1; | |
276 | else | |
277 | ret = idx_size; | |
278 | /* | |
279 | * The index head is not available for the in-the-gaps method, so add an | |
280 | * extra LEB to compensate. | |
281 | */ | |
282 | ret += 1; | |
283 | /* | |
284 | * At present the index needs at least 2 LEBs: one for the index head | |
285 | * and one for in-the-gaps method (which currently does not cater for | |
286 | * the index head and so excludes it from consideration). | |
287 | */ | |
288 | if (ret < 2) | |
289 | ret = 2; | |
290 | return ret; | |
291 | } | |
292 | ||
293 | /** | |
294 | * ubifs_calc_available - calculate available FS space. | |
295 | * @c: UBIFS file-system description object | |
296 | * @min_idx_lebs: minimum number of LEBs reserved for the index | |
297 | * | |
298 | * This function calculates and returns amount of FS space available for use. | |
299 | */ | |
300 | long long ubifs_calc_available(const struct ubifs_info *c, int min_idx_lebs) | |
301 | { | |
302 | int subtract_lebs; | |
303 | long long available; | |
304 | ||
305 | /* | |
306 | * Force the amount available to the total size reported if the used | |
307 | * space is zero. | |
308 | */ | |
309 | if (c->lst.total_used <= UBIFS_INO_NODE_SZ && | |
310 | c->budg_data_growth + c->budg_dd_growth == 0) { | |
311 | /* Do the same calculation as for c->block_cnt */ | |
312 | available = c->main_lebs - 2; | |
313 | available *= c->leb_size - c->dark_wm; | |
314 | return available; | |
315 | } | |
316 | ||
317 | available = c->main_bytes - c->lst.total_used; | |
318 | ||
319 | /* | |
320 | * Now 'available' contains theoretically available flash space | |
321 | * assuming there is no index, so we have to subtract the space which | |
322 | * is reserved for the index. | |
323 | */ | |
324 | subtract_lebs = min_idx_lebs; | |
325 | ||
326 | /* Take into account that GC reserves one LEB for its own needs */ | |
327 | subtract_lebs += 1; | |
328 | ||
329 | /* | |
330 | * The GC journal head LEB is not really accessible. And since | |
331 | * different write types go to different heads, we may count only on | |
332 | * one head's space. | |
333 | */ | |
334 | subtract_lebs += c->jhead_cnt - 1; | |
335 | ||
336 | /* We also reserve one LEB for deletions, which bypass budgeting */ | |
337 | subtract_lebs += 1; | |
338 | ||
339 | available -= (long long)subtract_lebs * c->leb_size; | |
340 | ||
341 | /* Subtract the dead space which is not available for use */ | |
342 | available -= c->lst.total_dead; | |
343 | ||
344 | /* | |
345 | * Subtract dark space, which might or might not be usable - it depends | |
346 | * on the data which we have on the media and which will be written. If | |
347 | * this is a lot of uncompressed or not-compressible data, the dark | |
348 | * space cannot be used. | |
349 | */ | |
350 | available -= c->lst.total_dark; | |
351 | ||
352 | /* | |
353 | * However, there is more dark space. The index may be bigger than | |
354 | * @min_idx_lebs. Those extra LEBs are assumed to be available, but | |
355 | * their dark space is not included in total_dark, so it is subtracted | |
356 | * here. | |
357 | */ | |
358 | if (c->lst.idx_lebs > min_idx_lebs) { | |
359 | subtract_lebs = c->lst.idx_lebs - min_idx_lebs; | |
360 | available -= subtract_lebs * c->dark_wm; | |
361 | } | |
362 | ||
363 | /* The calculations are rough and may end up with a negative number */ | |
364 | return available > 0 ? available : 0; | |
365 | } | |
366 | ||
367 | /** | |
368 | * can_use_rp - check whether the user is allowed to use reserved pool. | |
369 | * @c: UBIFS file-system description object | |
370 | * | |
371 | * UBIFS has so-called "reserved pool" which is flash space reserved | |
372 | * for the superuser and for uses whose UID/GID is recorded in UBIFS superblock. | |
373 | * This function checks whether current user is allowed to use reserved pool. | |
374 | * Returns %1 current user is allowed to use reserved pool and %0 otherwise. | |
375 | */ | |
376 | static int can_use_rp(struct ubifs_info *c) | |
377 | { | |
378 | if (current->fsuid == c->rp_uid || capable(CAP_SYS_RESOURCE) || | |
379 | (c->rp_gid != 0 && in_group_p(c->rp_gid))) | |
380 | return 1; | |
381 | return 0; | |
382 | } | |
383 | ||
384 | /** | |
385 | * do_budget_space - reserve flash space for index and data growth. | |
386 | * @c: UBIFS file-system description object | |
387 | * | |
388 | * This function makes sure UBIFS has enough free eraseblocks for index growth | |
389 | * and data. | |
390 | * | |
391 | * When budgeting index space, UBIFS reserves twice as more LEBs as the index | |
392 | * would take if it was consolidated and written to the flash. This guarantees | |
393 | * that the "in-the-gaps" commit method always succeeds and UBIFS will always | |
394 | * be able to commit dirty index. So this function basically adds amount of | |
395 | * budgeted index space to the size of the current index, multiplies this by 2, | |
396 | * and makes sure this does not exceed the amount of free eraseblocks. | |
397 | * | |
398 | * Notes about @c->min_idx_lebs and @c->lst.idx_lebs variables: | |
399 | * o @c->lst.idx_lebs is the number of LEBs the index currently uses. It might | |
400 | * be large, because UBIFS does not do any index consolidation as long as | |
401 | * there is free space. IOW, the index may take a lot of LEBs, but the LEBs | |
402 | * will contain a lot of dirt. | |
403 | * o @c->min_idx_lebs is the the index presumably takes. IOW, the index may be | |
404 | * consolidated to take up to @c->min_idx_lebs LEBs. | |
405 | * | |
406 | * This function returns zero in case of success, and %-ENOSPC in case of | |
407 | * failure. | |
408 | */ | |
409 | static int do_budget_space(struct ubifs_info *c) | |
410 | { | |
411 | long long outstanding, available; | |
412 | int lebs, rsvd_idx_lebs, min_idx_lebs; | |
413 | ||
414 | /* First budget index space */ | |
415 | min_idx_lebs = ubifs_calc_min_idx_lebs(c); | |
416 | ||
417 | /* Now 'min_idx_lebs' contains number of LEBs to reserve */ | |
418 | if (min_idx_lebs > c->lst.idx_lebs) | |
419 | rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs; | |
420 | else | |
421 | rsvd_idx_lebs = 0; | |
422 | ||
423 | /* | |
424 | * The number of LEBs that are available to be used by the index is: | |
425 | * | |
426 | * @c->lst.empty_lebs + @c->freeable_cnt + @c->idx_gc_cnt - | |
427 | * @c->lst.taken_empty_lebs | |
428 | * | |
429 | * @empty_lebs are available because they are empty. @freeable_cnt are | |
430 | * available because they contain only free and dirty space and the | |
431 | * index allocation always occurs after wbufs are synch'ed. | |
432 | * @idx_gc_cnt are available because they are index LEBs that have been | |
433 | * garbage collected (including trivial GC) and are awaiting the commit | |
434 | * before they can be unmapped - note that the in-the-gaps method will | |
435 | * grab these if it needs them. @taken_empty_lebs are empty_lebs that | |
436 | * have already been allocated for some purpose (also includes those | |
437 | * LEBs on the @idx_gc list). | |
438 | * | |
439 | * Note, @taken_empty_lebs may temporarily be higher by one because of | |
440 | * the way we serialize LEB allocations and budgeting. See a comment in | |
441 | * 'ubifs_find_free_space()'. | |
442 | */ | |
443 | lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt - | |
444 | c->lst.taken_empty_lebs; | |
445 | if (unlikely(rsvd_idx_lebs > lebs)) { | |
446 | dbg_budg("out of indexing space: min_idx_lebs %d (old %d), " | |
447 | "rsvd_idx_lebs %d", min_idx_lebs, c->min_idx_lebs, | |
448 | rsvd_idx_lebs); | |
449 | return -ENOSPC; | |
450 | } | |
451 | ||
452 | available = ubifs_calc_available(c, min_idx_lebs); | |
453 | outstanding = c->budg_data_growth + c->budg_dd_growth; | |
454 | ||
455 | if (unlikely(available < outstanding)) { | |
456 | dbg_budg("out of data space: available %lld, outstanding %lld", | |
457 | available, outstanding); | |
458 | return -ENOSPC; | |
459 | } | |
460 | ||
461 | if (available - outstanding <= c->rp_size && !can_use_rp(c)) | |
462 | return -ENOSPC; | |
463 | ||
464 | c->min_idx_lebs = min_idx_lebs; | |
465 | return 0; | |
466 | } | |
467 | ||
468 | /** | |
469 | * calc_idx_growth - calculate approximate index growth from budgeting request. | |
470 | * @c: UBIFS file-system description object | |
471 | * @req: budgeting request | |
472 | * | |
473 | * For now we assume each new node adds one znode. But this is rather poor | |
474 | * approximation, though. | |
475 | */ | |
476 | static int calc_idx_growth(const struct ubifs_info *c, | |
477 | const struct ubifs_budget_req *req) | |
478 | { | |
479 | int znodes; | |
480 | ||
481 | znodes = req->new_ino + (req->new_page << UBIFS_BLOCKS_PER_PAGE_SHIFT) + | |
482 | req->new_dent; | |
483 | return znodes * c->max_idx_node_sz; | |
484 | } | |
485 | ||
486 | /** | |
487 | * calc_data_growth - calculate approximate amount of new data from budgeting | |
488 | * request. | |
489 | * @c: UBIFS file-system description object | |
490 | * @req: budgeting request | |
491 | */ | |
492 | static int calc_data_growth(const struct ubifs_info *c, | |
493 | const struct ubifs_budget_req *req) | |
494 | { | |
495 | int data_growth; | |
496 | ||
497 | data_growth = req->new_ino ? c->inode_budget : 0; | |
498 | if (req->new_page) | |
499 | data_growth += c->page_budget; | |
500 | if (req->new_dent) | |
501 | data_growth += c->dent_budget; | |
502 | data_growth += req->new_ino_d; | |
503 | return data_growth; | |
504 | } | |
505 | ||
506 | /** | |
507 | * calc_dd_growth - calculate approximate amount of data which makes other data | |
508 | * dirty from budgeting request. | |
509 | * @c: UBIFS file-system description object | |
510 | * @req: budgeting request | |
511 | */ | |
512 | static int calc_dd_growth(const struct ubifs_info *c, | |
513 | const struct ubifs_budget_req *req) | |
514 | { | |
515 | int dd_growth; | |
516 | ||
517 | dd_growth = req->dirtied_page ? c->page_budget : 0; | |
518 | ||
519 | if (req->dirtied_ino) | |
520 | dd_growth += c->inode_budget << (req->dirtied_ino - 1); | |
521 | if (req->mod_dent) | |
522 | dd_growth += c->dent_budget; | |
523 | dd_growth += req->dirtied_ino_d; | |
524 | return dd_growth; | |
525 | } | |
526 | ||
527 | /** | |
528 | * ubifs_budget_space - ensure there is enough space to complete an operation. | |
529 | * @c: UBIFS file-system description object | |
530 | * @req: budget request | |
531 | * | |
532 | * This function allocates budget for an operation. It uses pessimistic | |
533 | * approximation of how much flash space the operation needs. The goal of this | |
534 | * function is to make sure UBIFS always has flash space to flush all dirty | |
535 | * pages, dirty inodes, and dirty znodes (liability). This function may force | |
536 | * commit, garbage-collection or write-back. Returns zero in case of success, | |
537 | * %-ENOSPC if there is no free space and other negative error codes in case of | |
538 | * failures. | |
539 | */ | |
540 | int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req) | |
541 | { | |
542 | int uninitialized_var(cmt_retries), uninitialized_var(wb_retries); | |
543 | int err, idx_growth, data_growth, dd_growth; | |
544 | struct retries_info ri; | |
545 | ||
546 | ubifs_assert(req->dirtied_ino <= 4); | |
547 | ubifs_assert(req->dirtied_ino_d <= UBIFS_MAX_INO_DATA * 4); | |
548 | ||
549 | data_growth = calc_data_growth(c, req); | |
550 | dd_growth = calc_dd_growth(c, req); | |
551 | if (!data_growth && !dd_growth) | |
552 | return 0; | |
553 | idx_growth = calc_idx_growth(c, req); | |
554 | memset(&ri, 0, sizeof(struct retries_info)); | |
555 | ||
556 | again: | |
557 | spin_lock(&c->space_lock); | |
558 | ubifs_assert(c->budg_idx_growth >= 0); | |
559 | ubifs_assert(c->budg_data_growth >= 0); | |
560 | ubifs_assert(c->budg_dd_growth >= 0); | |
561 | ||
562 | if (unlikely(c->nospace) && (c->nospace_rp || !can_use_rp(c))) { | |
563 | dbg_budg("no space"); | |
564 | spin_unlock(&c->space_lock); | |
565 | return -ENOSPC; | |
566 | } | |
567 | ||
568 | c->budg_idx_growth += idx_growth; | |
569 | c->budg_data_growth += data_growth; | |
570 | c->budg_dd_growth += dd_growth; | |
571 | ||
572 | err = do_budget_space(c); | |
573 | if (likely(!err)) { | |
574 | req->idx_growth = idx_growth; | |
575 | req->data_growth = data_growth; | |
576 | req->dd_growth = dd_growth; | |
577 | spin_unlock(&c->space_lock); | |
578 | return 0; | |
579 | } | |
580 | ||
581 | /* Restore the old values */ | |
582 | c->budg_idx_growth -= idx_growth; | |
583 | c->budg_data_growth -= data_growth; | |
584 | c->budg_dd_growth -= dd_growth; | |
585 | spin_unlock(&c->space_lock); | |
586 | ||
587 | if (req->fast) { | |
588 | dbg_budg("no space for fast budgeting"); | |
589 | return err; | |
590 | } | |
591 | ||
592 | err = make_free_space(c, &ri); | |
593 | if (err == -EAGAIN) { | |
594 | dbg_budg("try again"); | |
595 | cond_resched(); | |
596 | goto again; | |
597 | } else if (err == -ENOSPC) { | |
598 | dbg_budg("FS is full, -ENOSPC"); | |
599 | c->nospace = 1; | |
600 | if (can_use_rp(c) || c->rp_size == 0) | |
601 | c->nospace_rp = 1; | |
602 | smp_wmb(); | |
603 | } else | |
604 | ubifs_err("cannot budget space, error %d", err); | |
605 | return err; | |
606 | } | |
607 | ||
608 | /** | |
609 | * ubifs_release_budget - release budgeted free space. | |
610 | * @c: UBIFS file-system description object | |
611 | * @req: budget request | |
612 | * | |
613 | * This function releases the space budgeted by 'ubifs_budget_space()'. Note, | |
614 | * since the index changes (which were budgeted for in @req->idx_growth) will | |
615 | * only be written to the media on commit, this function moves the index budget | |
616 | * from @c->budg_idx_growth to @c->budg_uncommitted_idx. The latter will be | |
617 | * zeroed by the commit operation. | |
618 | */ | |
619 | void ubifs_release_budget(struct ubifs_info *c, struct ubifs_budget_req *req) | |
620 | { | |
621 | ubifs_assert(req->dirtied_ino <= 4); | |
622 | ubifs_assert(req->dirtied_ino_d <= UBIFS_MAX_INO_DATA * 4); | |
623 | if (!req->recalculate) { | |
624 | ubifs_assert(req->idx_growth >= 0); | |
625 | ubifs_assert(req->data_growth >= 0); | |
626 | ubifs_assert(req->dd_growth >= 0); | |
627 | } | |
628 | ||
629 | if (req->recalculate) { | |
630 | req->data_growth = calc_data_growth(c, req); | |
631 | req->dd_growth = calc_dd_growth(c, req); | |
632 | req->idx_growth = calc_idx_growth(c, req); | |
633 | } | |
634 | ||
635 | if (!req->data_growth && !req->dd_growth) | |
636 | return; | |
637 | ||
638 | c->nospace = c->nospace_rp = 0; | |
639 | smp_wmb(); | |
640 | ||
641 | spin_lock(&c->space_lock); | |
642 | c->budg_idx_growth -= req->idx_growth; | |
643 | c->budg_uncommitted_idx += req->idx_growth; | |
644 | c->budg_data_growth -= req->data_growth; | |
645 | c->budg_dd_growth -= req->dd_growth; | |
646 | c->min_idx_lebs = ubifs_calc_min_idx_lebs(c); | |
647 | ||
648 | ubifs_assert(c->budg_idx_growth >= 0); | |
649 | ubifs_assert(c->budg_data_growth >= 0); | |
650 | ubifs_assert(c->min_idx_lebs < c->main_lebs); | |
651 | spin_unlock(&c->space_lock); | |
652 | } | |
653 | ||
654 | /** | |
655 | * ubifs_convert_page_budget - convert budget of a new page. | |
656 | * @c: UBIFS file-system description object | |
657 | * | |
658 | * This function converts budget which was allocated for a new page of data to | |
659 | * the budget of changing an existing page of data. The latter is smaller then | |
660 | * the former, so this function only does simple re-calculation and does not | |
661 | * involve any write-back. | |
662 | */ | |
663 | void ubifs_convert_page_budget(struct ubifs_info *c) | |
664 | { | |
665 | spin_lock(&c->space_lock); | |
666 | /* Release the index growth reservation */ | |
667 | c->budg_idx_growth -= c->max_idx_node_sz << UBIFS_BLOCKS_PER_PAGE_SHIFT; | |
668 | /* Release the data growth reservation */ | |
669 | c->budg_data_growth -= c->page_budget; | |
670 | /* Increase the dirty data growth reservation instead */ | |
671 | c->budg_dd_growth += c->page_budget; | |
672 | /* And re-calculate the indexing space reservation */ | |
673 | c->min_idx_lebs = ubifs_calc_min_idx_lebs(c); | |
674 | spin_unlock(&c->space_lock); | |
675 | } | |
676 | ||
677 | /** | |
678 | * ubifs_release_dirty_inode_budget - release dirty inode budget. | |
679 | * @c: UBIFS file-system description object | |
680 | * @ui: UBIFS inode to release the budget for | |
681 | * | |
682 | * This function releases budget corresponding to a dirty inode. It is usually | |
683 | * called when after the inode has been written to the media and marked as | |
684 | * clean. | |
685 | */ | |
686 | void ubifs_release_dirty_inode_budget(struct ubifs_info *c, | |
687 | struct ubifs_inode *ui) | |
688 | { | |
689 | struct ubifs_budget_req req = {.dd_growth = c->inode_budget, | |
690 | .dirtied_ino_d = ui->data_len}; | |
691 | ||
692 | ubifs_release_budget(c, &req); | |
693 | } | |
694 | ||
695 | /** | |
696 | * ubifs_budg_get_free_space - return amount of free space. | |
697 | * @c: UBIFS file-system description object | |
698 | * | |
699 | * This function returns amount of free space on the file-system. | |
700 | */ | |
701 | long long ubifs_budg_get_free_space(struct ubifs_info *c) | |
702 | { | |
703 | int min_idx_lebs, rsvd_idx_lebs; | |
704 | long long available, outstanding, free; | |
705 | ||
706 | /* Do exactly the same calculations as in 'do_budget_space()' */ | |
707 | spin_lock(&c->space_lock); | |
708 | min_idx_lebs = ubifs_calc_min_idx_lebs(c); | |
709 | ||
710 | if (min_idx_lebs > c->lst.idx_lebs) | |
711 | rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs; | |
712 | else | |
713 | rsvd_idx_lebs = 0; | |
714 | ||
715 | if (rsvd_idx_lebs > c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt | |
716 | - c->lst.taken_empty_lebs) { | |
717 | spin_unlock(&c->space_lock); | |
718 | return 0; | |
719 | } | |
720 | ||
721 | available = ubifs_calc_available(c, min_idx_lebs); | |
722 | outstanding = c->budg_data_growth + c->budg_dd_growth; | |
723 | c->min_idx_lebs = min_idx_lebs; | |
724 | spin_unlock(&c->space_lock); | |
725 | ||
726 | if (available > outstanding) | |
727 | free = ubifs_reported_space(c, available - outstanding); | |
728 | else | |
729 | free = 0; | |
730 | return free; | |
731 | } |