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Diffstat (limited to 'fs/ubifs/budget.c')
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diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c new file mode 100644 index 000000000000..d81fb9ed2b8e --- /dev/null +++ b/fs/ubifs/budget.c | |||
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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 | } | ||