1 // SPDX-License-Identifier: GPL-2.0+
3 * This file is part of UBIFS.
5 * Copyright (C) 2006-2008 Nokia Corporation.
7 * Authors: Adrian Hunter
8 * Artem Bityutskiy (Битюцкий Артём)
12 * This file implements the budgeting sub-system which is responsible for UBIFS
15 * Factors such as compression, wasted space at the ends of LEBs, space in other
16 * journal heads, the effect of updates on the index, and so on, make it
17 * impossible to accurately predict the amount of space needed. Consequently
18 * approximations are used.
23 #include <linux/writeback.h>
25 #include <linux/err.h>
27 #include <linux/math64.h>
30 * When pessimistic budget calculations say that there is no enough space,
31 * UBIFS starts writing back dirty inodes and pages, doing garbage collection,
32 * or committing. The below constant defines maximum number of times UBIFS
33 * repeats the operations.
35 #define MAX_MKSPC_RETRIES 3
38 * The below constant defines amount of dirty pages which should be written
39 * back at when trying to shrink the liability.
41 #define NR_TO_WRITE 16
45 * shrink_liability - write-back some dirty pages/inodes.
46 * @c: UBIFS file-system description object
47 * @nr_to_write: how many dirty pages to write-back
49 * This function shrinks UBIFS liability by means of writing back some amount
50 * of dirty inodes and their pages.
52 * Note, this function synchronizes even VFS inodes which are locked
53 * (@i_mutex) by the caller of the budgeting function, because write-back does
56 static void shrink_liability(struct ubifs_info
*c
, int nr_to_write
)
58 down_read(&c
->vfs_sb
->s_umount
);
59 writeback_inodes_sb(c
->vfs_sb
, WB_REASON_FS_FREE_SPACE
);
60 up_read(&c
->vfs_sb
->s_umount
);
64 * run_gc - run garbage collector.
65 * @c: UBIFS file-system description object
67 * This function runs garbage collector to make some more free space. Returns
68 * zero if a free LEB has been produced, %-EAGAIN if commit is required, and a
69 * negative error code in case of failure.
71 static int run_gc(struct ubifs_info
*c
)
75 /* Make some free space by garbage-collecting dirty space */
76 down_read(&c
->commit_sem
);
77 lnum
= ubifs_garbage_collect(c
, 1);
78 up_read(&c
->commit_sem
);
82 /* GC freed one LEB, return it to lprops */
83 dbg_budg("GC freed LEB %d", lnum
);
84 err
= ubifs_return_leb(c
, lnum
);
91 * get_liability - calculate current liability.
92 * @c: UBIFS file-system description object
94 * This function calculates and returns current UBIFS liability, i.e. the
95 * amount of bytes UBIFS has "promised" to write to the media.
97 static long long get_liability(struct ubifs_info
*c
)
101 spin_lock(&c
->space_lock
);
102 liab
= c
->bi
.idx_growth
+ c
->bi
.data_growth
+ c
->bi
.dd_growth
;
103 spin_unlock(&c
->space_lock
);
108 * make_free_space - make more free space on the file-system.
109 * @c: UBIFS file-system description object
111 * This function is called when an operation cannot be budgeted because there
112 * is supposedly no free space. But in most cases there is some free space:
113 * o budgeting is pessimistic, so it always budgets more than it is actually
114 * needed, so shrinking the liability is one way to make free space - the
115 * cached data will take less space then it was budgeted for;
116 * o GC may turn some dark space into free space (budgeting treats dark space
118 * o commit may free some LEB, i.e., turn freeable LEBs into free LEBs.
120 * So this function tries to do the above. Returns %-EAGAIN if some free space
121 * was presumably made and the caller has to re-try budgeting the operation.
122 * Returns %-ENOSPC if it couldn't do more free space, and other negative error
125 static int make_free_space(struct ubifs_info
*c
)
127 int err
, retries
= 0;
128 long long liab1
, liab2
;
131 liab1
= get_liability(c
);
133 * We probably have some dirty pages or inodes (liability), try
134 * to write them back.
136 dbg_budg("liability %lld, run write-back", liab1
);
137 shrink_liability(c
, NR_TO_WRITE
);
139 liab2
= get_liability(c
);
143 dbg_budg("new liability %lld (not shrunk)", liab2
);
145 /* Liability did not shrink again, try GC */
151 if (err
!= -EAGAIN
&& err
!= -ENOSPC
)
152 /* Some real error happened */
155 dbg_budg("Run commit (retries %d)", retries
);
156 err
= ubifs_run_commit(c
);
159 } while (retries
++ < MAX_MKSPC_RETRIES
);
166 * ubifs_calc_min_idx_lebs - calculate amount of LEBs for the index.
167 * @c: UBIFS file-system description object
169 * This function calculates and returns the number of LEBs which should be kept
172 int ubifs_calc_min_idx_lebs(struct ubifs_info
*c
)
177 idx_size
= c
->bi
.old_idx_sz
+ c
->bi
.idx_growth
+ c
->bi
.uncommitted_idx
;
178 /* And make sure we have thrice the index size of space reserved */
179 idx_size
+= idx_size
<< 1;
181 * We do not maintain 'old_idx_size' as 'old_idx_lebs'/'old_idx_bytes'
182 * pair, nor similarly the two variables for the new index size, so we
183 * have to do this costly 64-bit division on fast-path.
185 idx_lebs
= div_u64(idx_size
+ c
->idx_leb_size
- 1, c
->idx_leb_size
);
187 * The index head is not available for the in-the-gaps method, so add an
188 * extra LEB to compensate.
191 if (idx_lebs
< MIN_INDEX_LEBS
)
192 idx_lebs
= MIN_INDEX_LEBS
;
198 * ubifs_calc_available - calculate available FS space.
199 * @c: UBIFS file-system description object
200 * @min_idx_lebs: minimum number of LEBs reserved for the index
202 * This function calculates and returns amount of FS space available for use.
204 long long ubifs_calc_available(const struct ubifs_info
*c
, int min_idx_lebs
)
209 available
= c
->main_bytes
- c
->lst
.total_used
;
212 * Now 'available' contains theoretically available flash space
213 * assuming there is no index, so we have to subtract the space which
214 * is reserved for the index.
216 subtract_lebs
= min_idx_lebs
;
218 /* Take into account that GC reserves one LEB for its own needs */
222 * The GC journal head LEB is not really accessible. And since
223 * different write types go to different heads, we may count only on
226 subtract_lebs
+= c
->jhead_cnt
- 1;
228 /* We also reserve one LEB for deletions, which bypass budgeting */
231 available
-= (long long)subtract_lebs
* c
->leb_size
;
233 /* Subtract the dead space which is not available for use */
234 available
-= c
->lst
.total_dead
;
237 * Subtract dark space, which might or might not be usable - it depends
238 * on the data which we have on the media and which will be written. If
239 * this is a lot of uncompressed or not-compressible data, the dark
240 * space cannot be used.
242 available
-= c
->lst
.total_dark
;
245 * However, there is more dark space. The index may be bigger than
246 * @min_idx_lebs. Those extra LEBs are assumed to be available, but
247 * their dark space is not included in total_dark, so it is subtracted
250 if (c
->lst
.idx_lebs
> min_idx_lebs
) {
251 subtract_lebs
= c
->lst
.idx_lebs
- min_idx_lebs
;
252 available
-= subtract_lebs
* c
->dark_wm
;
255 /* The calculations are rough and may end up with a negative number */
256 return available
> 0 ? available
: 0;
260 * can_use_rp - check whether the user is allowed to use reserved pool.
261 * @c: UBIFS file-system description object
263 * UBIFS has so-called "reserved pool" which is flash space reserved
264 * for the superuser and for uses whose UID/GID is recorded in UBIFS superblock.
265 * This function checks whether current user is allowed to use reserved pool.
266 * Returns %1 current user is allowed to use reserved pool and %0 otherwise.
268 static int can_use_rp(struct ubifs_info
*c
)
270 if (uid_eq(current_fsuid(), c
->rp_uid
) || capable(CAP_SYS_RESOURCE
) ||
271 (!gid_eq(c
->rp_gid
, GLOBAL_ROOT_GID
) && in_group_p(c
->rp_gid
)))
277 * do_budget_space - reserve flash space for index and data growth.
278 * @c: UBIFS file-system description object
280 * This function makes sure UBIFS has enough free LEBs for index growth and
283 * When budgeting index space, UBIFS reserves thrice as many LEBs as the index
284 * would take if it was consolidated and written to the flash. This guarantees
285 * that the "in-the-gaps" commit method always succeeds and UBIFS will always
286 * be able to commit dirty index. So this function basically adds amount of
287 * budgeted index space to the size of the current index, multiplies this by 3,
288 * and makes sure this does not exceed the amount of free LEBs.
290 * Notes about @c->bi.min_idx_lebs and @c->lst.idx_lebs variables:
291 * o @c->lst.idx_lebs is the number of LEBs the index currently uses. It might
292 * be large, because UBIFS does not do any index consolidation as long as
293 * there is free space. IOW, the index may take a lot of LEBs, but the LEBs
294 * will contain a lot of dirt.
295 * o @c->bi.min_idx_lebs is the number of LEBS the index presumably takes. IOW,
296 * the index may be consolidated to take up to @c->bi.min_idx_lebs LEBs.
298 * This function returns zero in case of success, and %-ENOSPC in case of
301 static int do_budget_space(struct ubifs_info
*c
)
303 long long outstanding
, available
;
304 int lebs
, rsvd_idx_lebs
, min_idx_lebs
;
306 /* First budget index space */
307 min_idx_lebs
= ubifs_calc_min_idx_lebs(c
);
309 /* Now 'min_idx_lebs' contains number of LEBs to reserve */
310 if (min_idx_lebs
> c
->lst
.idx_lebs
)
311 rsvd_idx_lebs
= min_idx_lebs
- c
->lst
.idx_lebs
;
316 * The number of LEBs that are available to be used by the index is:
318 * @c->lst.empty_lebs + @c->freeable_cnt + @c->idx_gc_cnt -
319 * @c->lst.taken_empty_lebs
321 * @c->lst.empty_lebs are available because they are empty.
322 * @c->freeable_cnt are available because they contain only free and
323 * dirty space, @c->idx_gc_cnt are available because they are index
324 * LEBs that have been garbage collected and are awaiting the commit
325 * before they can be used. And the in-the-gaps method will grab these
326 * if it needs them. @c->lst.taken_empty_lebs are empty LEBs that have
327 * already been allocated for some purpose.
329 * Note, @c->idx_gc_cnt is included to both @c->lst.empty_lebs (because
330 * these LEBs are empty) and to @c->lst.taken_empty_lebs (because they
331 * are taken until after the commit).
333 * Note, @c->lst.taken_empty_lebs may temporarily be higher by one
334 * because of the way we serialize LEB allocations and budgeting. See a
335 * comment in 'ubifs_find_free_space()'.
337 lebs
= c
->lst
.empty_lebs
+ c
->freeable_cnt
+ c
->idx_gc_cnt
-
338 c
->lst
.taken_empty_lebs
;
339 if (unlikely(rsvd_idx_lebs
> lebs
)) {
340 dbg_budg("out of indexing space: min_idx_lebs %d (old %d), rsvd_idx_lebs %d",
341 min_idx_lebs
, c
->bi
.min_idx_lebs
, rsvd_idx_lebs
);
345 available
= ubifs_calc_available(c
, min_idx_lebs
);
346 outstanding
= c
->bi
.data_growth
+ c
->bi
.dd_growth
;
348 if (unlikely(available
< outstanding
)) {
349 dbg_budg("out of data space: available %lld, outstanding %lld",
350 available
, outstanding
);
354 if (available
- outstanding
<= c
->rp_size
&& !can_use_rp(c
))
357 c
->bi
.min_idx_lebs
= min_idx_lebs
;
362 * calc_idx_growth - calculate approximate index growth from budgeting request.
363 * @c: UBIFS file-system description object
364 * @req: budgeting request
366 * For now we assume each new node adds one znode. But this is rather poor
367 * approximation, though.
369 static int calc_idx_growth(const struct ubifs_info
*c
,
370 const struct ubifs_budget_req
*req
)
374 znodes
= req
->new_ino
+ (req
->new_page
<< UBIFS_BLOCKS_PER_PAGE_SHIFT
) +
376 return znodes
* c
->max_idx_node_sz
;
380 * calc_data_growth - calculate approximate amount of new data from budgeting
382 * @c: UBIFS file-system description object
383 * @req: budgeting request
385 static int calc_data_growth(const struct ubifs_info
*c
,
386 const struct ubifs_budget_req
*req
)
390 data_growth
= req
->new_ino
? c
->bi
.inode_budget
: 0;
392 data_growth
+= c
->bi
.page_budget
;
394 data_growth
+= c
->bi
.dent_budget
;
395 data_growth
+= req
->new_ino_d
;
400 * calc_dd_growth - calculate approximate amount of data which makes other data
401 * dirty from budgeting request.
402 * @c: UBIFS file-system description object
403 * @req: budgeting request
405 static int calc_dd_growth(const struct ubifs_info
*c
,
406 const struct ubifs_budget_req
*req
)
410 dd_growth
= req
->dirtied_page
? c
->bi
.page_budget
: 0;
412 if (req
->dirtied_ino
)
413 dd_growth
+= c
->bi
.inode_budget
<< (req
->dirtied_ino
- 1);
415 dd_growth
+= c
->bi
.dent_budget
;
416 dd_growth
+= req
->dirtied_ino_d
;
421 * ubifs_budget_space - ensure there is enough space to complete an operation.
422 * @c: UBIFS file-system description object
423 * @req: budget request
425 * This function allocates budget for an operation. It uses pessimistic
426 * approximation of how much flash space the operation needs. The goal of this
427 * function is to make sure UBIFS always has flash space to flush all dirty
428 * pages, dirty inodes, and dirty znodes (liability). This function may force
429 * commit, garbage-collection or write-back. Returns zero in case of success,
430 * %-ENOSPC if there is no free space and other negative error codes in case of
433 int ubifs_budget_space(struct ubifs_info
*c
, struct ubifs_budget_req
*req
)
435 int err
, idx_growth
, data_growth
, dd_growth
, retried
= 0;
437 ubifs_assert(req
->new_page
<= 1);
438 ubifs_assert(req
->dirtied_page
<= 1);
439 ubifs_assert(req
->new_dent
<= 1);
440 ubifs_assert(req
->mod_dent
<= 1);
441 ubifs_assert(req
->new_ino
<= 1);
442 ubifs_assert(req
->new_ino_d
<= UBIFS_MAX_INO_DATA
);
443 ubifs_assert(req
->dirtied_ino
<= 4);
444 ubifs_assert(req
->dirtied_ino_d
<= UBIFS_MAX_INO_DATA
* 4);
445 ubifs_assert(!(req
->new_ino_d
& 7));
446 ubifs_assert(!(req
->dirtied_ino_d
& 7));
448 data_growth
= calc_data_growth(c
, req
);
449 dd_growth
= calc_dd_growth(c
, req
);
450 if (!data_growth
&& !dd_growth
)
452 idx_growth
= calc_idx_growth(c
, req
);
455 spin_lock(&c
->space_lock
);
456 ubifs_assert(c
->bi
.idx_growth
>= 0);
457 ubifs_assert(c
->bi
.data_growth
>= 0);
458 ubifs_assert(c
->bi
.dd_growth
>= 0);
460 if (unlikely(c
->bi
.nospace
) && (c
->bi
.nospace_rp
|| !can_use_rp(c
))) {
461 dbg_budg("no space");
462 spin_unlock(&c
->space_lock
);
466 c
->bi
.idx_growth
+= idx_growth
;
467 c
->bi
.data_growth
+= data_growth
;
468 c
->bi
.dd_growth
+= dd_growth
;
470 err
= do_budget_space(c
);
472 req
->idx_growth
= idx_growth
;
473 req
->data_growth
= data_growth
;
474 req
->dd_growth
= dd_growth
;
475 spin_unlock(&c
->space_lock
);
479 /* Restore the old values */
480 c
->bi
.idx_growth
-= idx_growth
;
481 c
->bi
.data_growth
-= data_growth
;
482 c
->bi
.dd_growth
-= dd_growth
;
483 spin_unlock(&c
->space_lock
);
486 dbg_budg("no space for fast budgeting");
490 err
= make_free_space(c
);
492 if (err
== -EAGAIN
) {
493 dbg_budg("try again");
495 } else if (err
== -ENOSPC
) {
498 dbg_budg("-ENOSPC, but anyway try once again");
501 dbg_budg("FS is full, -ENOSPC");
503 if (can_use_rp(c
) || c
->rp_size
== 0)
504 c
->bi
.nospace_rp
= 1;
507 ubifs_err(c
, "cannot budget space, error %d", err
);
512 * ubifs_release_budget - release budgeted free space.
513 * @c: UBIFS file-system description object
514 * @req: budget request
516 * This function releases the space budgeted by 'ubifs_budget_space()'. Note,
517 * since the index changes (which were budgeted for in @req->idx_growth) will
518 * only be written to the media on commit, this function moves the index budget
519 * from @c->bi.idx_growth to @c->bi.uncommitted_idx. The latter will be zeroed
520 * by the commit operation.
522 void ubifs_release_budget(struct ubifs_info
*c
, struct ubifs_budget_req
*req
)
524 ubifs_assert(req
->new_page
<= 1);
525 ubifs_assert(req
->dirtied_page
<= 1);
526 ubifs_assert(req
->new_dent
<= 1);
527 ubifs_assert(req
->mod_dent
<= 1);
528 ubifs_assert(req
->new_ino
<= 1);
529 ubifs_assert(req
->new_ino_d
<= UBIFS_MAX_INO_DATA
);
530 ubifs_assert(req
->dirtied_ino
<= 4);
531 ubifs_assert(req
->dirtied_ino_d
<= UBIFS_MAX_INO_DATA
* 4);
532 ubifs_assert(!(req
->new_ino_d
& 7));
533 ubifs_assert(!(req
->dirtied_ino_d
& 7));
534 if (!req
->recalculate
) {
535 ubifs_assert(req
->idx_growth
>= 0);
536 ubifs_assert(req
->data_growth
>= 0);
537 ubifs_assert(req
->dd_growth
>= 0);
540 if (req
->recalculate
) {
541 req
->data_growth
= calc_data_growth(c
, req
);
542 req
->dd_growth
= calc_dd_growth(c
, req
);
543 req
->idx_growth
= calc_idx_growth(c
, req
);
546 if (!req
->data_growth
&& !req
->dd_growth
)
549 c
->bi
.nospace
= c
->bi
.nospace_rp
= 0;
552 spin_lock(&c
->space_lock
);
553 c
->bi
.idx_growth
-= req
->idx_growth
;
554 c
->bi
.uncommitted_idx
+= req
->idx_growth
;
555 c
->bi
.data_growth
-= req
->data_growth
;
556 c
->bi
.dd_growth
-= req
->dd_growth
;
557 c
->bi
.min_idx_lebs
= ubifs_calc_min_idx_lebs(c
);
559 ubifs_assert(c
->bi
.idx_growth
>= 0);
560 ubifs_assert(c
->bi
.data_growth
>= 0);
561 ubifs_assert(c
->bi
.dd_growth
>= 0);
562 ubifs_assert(c
->bi
.min_idx_lebs
< c
->main_lebs
);
563 ubifs_assert(!(c
->bi
.idx_growth
& 7));
564 ubifs_assert(!(c
->bi
.data_growth
& 7));
565 ubifs_assert(!(c
->bi
.dd_growth
& 7));
566 spin_unlock(&c
->space_lock
);
570 * ubifs_convert_page_budget - convert budget of a new page.
571 * @c: UBIFS file-system description object
573 * This function converts budget which was allocated for a new page of data to
574 * the budget of changing an existing page of data. The latter is smaller than
575 * the former, so this function only does simple re-calculation and does not
576 * involve any write-back.
578 void ubifs_convert_page_budget(struct ubifs_info
*c
)
580 spin_lock(&c
->space_lock
);
581 /* Release the index growth reservation */
582 c
->bi
.idx_growth
-= c
->max_idx_node_sz
<< UBIFS_BLOCKS_PER_PAGE_SHIFT
;
583 /* Release the data growth reservation */
584 c
->bi
.data_growth
-= c
->bi
.page_budget
;
585 /* Increase the dirty data growth reservation instead */
586 c
->bi
.dd_growth
+= c
->bi
.page_budget
;
587 /* And re-calculate the indexing space reservation */
588 c
->bi
.min_idx_lebs
= ubifs_calc_min_idx_lebs(c
);
589 spin_unlock(&c
->space_lock
);
593 * ubifs_release_dirty_inode_budget - release dirty inode budget.
594 * @c: UBIFS file-system description object
595 * @ui: UBIFS inode to release the budget for
597 * This function releases budget corresponding to a dirty inode. It is usually
598 * called when after the inode has been written to the media and marked as
599 * clean. It also causes the "no space" flags to be cleared.
601 void ubifs_release_dirty_inode_budget(struct ubifs_info
*c
,
602 struct ubifs_inode
*ui
)
604 struct ubifs_budget_req req
;
606 memset(&req
, 0, sizeof(struct ubifs_budget_req
));
607 /* The "no space" flags will be cleared because dd_growth is > 0 */
608 req
.dd_growth
= c
->bi
.inode_budget
+ ALIGN(ui
->data_len
, 8);
609 ubifs_release_budget(c
, &req
);
614 * ubifs_reported_space - calculate reported free space.
615 * @c: the UBIFS file-system description object
616 * @free: amount of free space
618 * This function calculates amount of free space which will be reported to
619 * user-space. User-space application tend to expect that if the file-system
620 * (e.g., via the 'statfs()' call) reports that it has N bytes available, they
621 * are able to write a file of size N. UBIFS attaches node headers to each data
622 * node and it has to write indexing nodes as well. This introduces additional
623 * overhead, and UBIFS has to report slightly less free space to meet the above
626 * This function assumes free space is made up of uncompressed data nodes and
627 * full index nodes (one per data node, tripled because we always allow enough
628 * space to write the index thrice).
630 * Note, the calculation is pessimistic, which means that most of the time
631 * UBIFS reports less space than it actually has.
633 long long ubifs_reported_space(const struct ubifs_info
*c
, long long free
)
635 int divisor
, factor
, f
;
638 * Reported space size is @free * X, where X is UBIFS block size
639 * divided by UBIFS block size + all overhead one data block
640 * introduces. The overhead is the node header + indexing overhead.
642 * Indexing overhead calculations are based on the following formula:
643 * I = N/(f - 1) + 1, where I - number of indexing nodes, N - number
644 * of data nodes, f - fanout. Because effective UBIFS fanout is twice
645 * as less than maximum fanout, we assume that each data node
646 * introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes.
647 * Note, the multiplier 3 is because UBIFS reserves thrice as more space
650 f
= c
->fanout
> 3 ? c
->fanout
>> 1 : 2;
651 factor
= UBIFS_BLOCK_SIZE
;
652 divisor
= UBIFS_MAX_DATA_NODE_SZ
;
653 divisor
+= (c
->max_idx_node_sz
* 3) / (f
- 1);
655 return div_u64(free
, divisor
);
660 * ubifs_get_free_space_nolock - return amount of free space.
661 * @c: UBIFS file-system description object
663 * This function calculates amount of free space to report to user-space.
665 * Because UBIFS may introduce substantial overhead (the index, node headers,
666 * alignment, wastage at the end of LEBs, etc), it cannot report real amount of
667 * free flash space it has (well, because not all dirty space is reclaimable,
668 * UBIFS does not actually know the real amount). If UBIFS did so, it would
669 * bread user expectations about what free space is. Users seem to accustomed
670 * to assume that if the file-system reports N bytes of free space, they would
671 * be able to fit a file of N bytes to the FS. This almost works for
672 * traditional file-systems, because they have way less overhead than UBIFS.
673 * So, to keep users happy, UBIFS tries to take the overhead into account.
675 long long ubifs_get_free_space_nolock(struct ubifs_info
*c
)
677 int rsvd_idx_lebs
, lebs
;
678 long long available
, outstanding
, free
;
680 ubifs_assert(c
->bi
.min_idx_lebs
== ubifs_calc_min_idx_lebs(c
));
681 outstanding
= c
->bi
.data_growth
+ c
->bi
.dd_growth
;
682 available
= ubifs_calc_available(c
, c
->bi
.min_idx_lebs
);
685 * When reporting free space to user-space, UBIFS guarantees that it is
686 * possible to write a file of free space size. This means that for
687 * empty LEBs we may use more precise calculations than
688 * 'ubifs_calc_available()' is using. Namely, we know that in empty
689 * LEBs we would waste only @c->leb_overhead bytes, not @c->dark_wm.
690 * Thus, amend the available space.
692 * Note, the calculations below are similar to what we have in
693 * 'do_budget_space()', so refer there for comments.
695 if (c
->bi
.min_idx_lebs
> c
->lst
.idx_lebs
)
696 rsvd_idx_lebs
= c
->bi
.min_idx_lebs
- c
->lst
.idx_lebs
;
699 lebs
= c
->lst
.empty_lebs
+ c
->freeable_cnt
+ c
->idx_gc_cnt
-
700 c
->lst
.taken_empty_lebs
;
701 lebs
-= rsvd_idx_lebs
;
702 available
+= lebs
* (c
->dark_wm
- c
->leb_overhead
);
704 if (available
> outstanding
)
705 free
= ubifs_reported_space(c
, available
- outstanding
);
712 * ubifs_get_free_space - return amount of free space.
713 * @c: UBIFS file-system description object
715 * This function calculates and returns amount of free space to report to
718 long long ubifs_get_free_space(struct ubifs_info
*c
)
722 spin_lock(&c
->space_lock
);
723 free
= ubifs_get_free_space_nolock(c
);
724 spin_unlock(&c
->space_lock
);