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2b27bdcc | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1e51764a AB |
2 | /* |
3 | * This file is part of UBIFS. | |
4 | * | |
5 | * Copyright (C) 2006-2008 Nokia Corporation. | |
6 | * | |
1e51764a AB |
7 | * Authors: Adrian Hunter |
8 | * Artem Bityutskiy (Битюцкий Артём) | |
9 | */ | |
10 | ||
11 | /* | |
12 | * This file implements garbage collection. The procedure for garbage collection | |
13 | * is different depending on whether a LEB as an index LEB (contains index | |
14 | * nodes) or not. For non-index LEBs, garbage collection finds a LEB which | |
15 | * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete | |
16 | * nodes to the journal, at which point the garbage-collected LEB is free to be | |
17 | * reused. For index LEBs, garbage collection marks the non-obsolete index nodes | |
18 | * dirty in the TNC, and after the next commit, the garbage-collected LEB is | |
19 | * to be reused. Garbage collection will cause the number of dirty index nodes | |
20 | * to grow, however sufficient space is reserved for the index to ensure the | |
21 | * commit will never run out of space. | |
7078202e AB |
22 | * |
23 | * Notes about dead watermark. At current UBIFS implementation we assume that | |
24 | * LEBs which have less than @c->dead_wm bytes of free + dirty space are full | |
25 | * and not worth garbage-collecting. The dead watermark is one min. I/O unit | |
26 | * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS | |
27 | * Garbage Collector has to synchronize the GC head's write buffer before | |
28 | * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can | |
29 | * actually reclaim even very small pieces of dirty space by garbage collecting | |
30 | * enough dirty LEBs, but we do not bother doing this at this implementation. | |
31 | * | |
32 | * Notes about dark watermark. The results of GC work depends on how big are | |
33 | * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed, | |
34 | * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would | |
35 | * have to waste large pieces of free space at the end of LEB B, because nodes | |
36 | * from LEB A would not fit. And the worst situation is when all nodes are of | |
37 | * maximum size. So dark watermark is the amount of free + dirty space in LEB | |
f10770f5 | 38 | * which are guaranteed to be reclaimable. If LEB has less space, the GC might |
7078202e | 39 | * be unable to reclaim it. So, LEBs with free + dirty greater than dark |
28e5dfd8 | 40 | * watermark are "good" LEBs from GC's point of view. The other LEBs are not so |
7078202e | 41 | * good, and GC takes extra care when moving them. |
1e51764a AB |
42 | */ |
43 | ||
5a0e3ad6 | 44 | #include <linux/slab.h> |
1e51764a | 45 | #include <linux/pagemap.h> |
2c761270 | 46 | #include <linux/list_sort.h> |
1e51764a AB |
47 | #include "ubifs.h" |
48 | ||
1e51764a | 49 | /* |
025dfdaf | 50 | * GC may need to move more than one LEB to make progress. The below constants |
1e51764a AB |
51 | * define "soft" and "hard" limits on the number of LEBs the garbage collector |
52 | * may move. | |
53 | */ | |
54 | #define SOFT_LEBS_LIMIT 4 | |
55 | #define HARD_LEBS_LIMIT 32 | |
56 | ||
57 | /** | |
58 | * switch_gc_head - switch the garbage collection journal head. | |
59 | * @c: UBIFS file-system description object | |
1e51764a AB |
60 | * |
61 | * This function switch the GC head to the next LEB which is reserved in | |
62 | * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required, | |
63 | * and other negative error code in case of failures. | |
64 | */ | |
65 | static int switch_gc_head(struct ubifs_info *c) | |
66 | { | |
67 | int err, gc_lnum = c->gc_lnum; | |
68 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
69 | ||
6eb61d58 | 70 | ubifs_assert(c, gc_lnum != -1); |
1e51764a AB |
71 | dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)", |
72 | wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum, | |
73 | c->leb_size - wbuf->offs - wbuf->used); | |
74 | ||
75 | err = ubifs_wbuf_sync_nolock(wbuf); | |
76 | if (err) | |
77 | return err; | |
78 | ||
79 | /* | |
80 | * The GC write-buffer was synchronized, we may safely unmap | |
81 | * 'c->gc_lnum'. | |
82 | */ | |
83 | err = ubifs_leb_unmap(c, gc_lnum); | |
84 | if (err) | |
85 | return err; | |
86 | ||
87 | err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0); | |
88 | if (err) | |
89 | return err; | |
90 | ||
91 | c->gc_lnum = -1; | |
b36a261e | 92 | err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0); |
1e51764a AB |
93 | return err; |
94 | } | |
95 | ||
96 | /** | |
f10770f5 AB |
97 | * data_nodes_cmp - compare 2 data nodes. |
98 | * @priv: UBIFS file-system description object | |
99 | * @a: first data node | |
ec037dfc | 100 | * @b: second data node |
f10770f5 AB |
101 | * |
102 | * This function compares data nodes @a and @b. Returns %1 if @a has greater | |
103 | * inode or block number, and %-1 otherwise. | |
104 | */ | |
4f0f586b ST |
105 | static int data_nodes_cmp(void *priv, const struct list_head *a, |
106 | const struct list_head *b) | |
f10770f5 AB |
107 | { |
108 | ino_t inuma, inumb; | |
109 | struct ubifs_info *c = priv; | |
110 | struct ubifs_scan_node *sa, *sb; | |
111 | ||
112 | cond_resched(); | |
1a9476a7 AB |
113 | if (a == b) |
114 | return 0; | |
115 | ||
f10770f5 AB |
116 | sa = list_entry(a, struct ubifs_scan_node, list); |
117 | sb = list_entry(b, struct ubifs_scan_node, list); | |
66576833 | 118 | |
6eb61d58 RW |
119 | ubifs_assert(c, key_type(c, &sa->key) == UBIFS_DATA_KEY); |
120 | ubifs_assert(c, key_type(c, &sb->key) == UBIFS_DATA_KEY); | |
121 | ubifs_assert(c, sa->type == UBIFS_DATA_NODE); | |
122 | ubifs_assert(c, sb->type == UBIFS_DATA_NODE); | |
f10770f5 AB |
123 | |
124 | inuma = key_inum(c, &sa->key); | |
125 | inumb = key_inum(c, &sb->key); | |
126 | ||
127 | if (inuma == inumb) { | |
128 | unsigned int blka = key_block(c, &sa->key); | |
129 | unsigned int blkb = key_block(c, &sb->key); | |
130 | ||
131 | if (blka <= blkb) | |
132 | return -1; | |
133 | } else if (inuma <= inumb) | |
134 | return -1; | |
135 | ||
136 | return 1; | |
137 | } | |
138 | ||
139 | /* | |
140 | * nondata_nodes_cmp - compare 2 non-data nodes. | |
141 | * @priv: UBIFS file-system description object | |
142 | * @a: first node | |
143 | * @a: second node | |
144 | * | |
145 | * This function compares nodes @a and @b. It makes sure that inode nodes go | |
146 | * first and sorted by length in descending order. Directory entry nodes go | |
147 | * after inode nodes and are sorted in ascending hash valuer order. | |
148 | */ | |
4f0f586b ST |
149 | static int nondata_nodes_cmp(void *priv, const struct list_head *a, |
150 | const struct list_head *b) | |
f10770f5 | 151 | { |
f10770f5 AB |
152 | ino_t inuma, inumb; |
153 | struct ubifs_info *c = priv; | |
154 | struct ubifs_scan_node *sa, *sb; | |
155 | ||
156 | cond_resched(); | |
1a9476a7 AB |
157 | if (a == b) |
158 | return 0; | |
159 | ||
f10770f5 AB |
160 | sa = list_entry(a, struct ubifs_scan_node, list); |
161 | sb = list_entry(b, struct ubifs_scan_node, list); | |
66576833 | 162 | |
6eb61d58 | 163 | ubifs_assert(c, key_type(c, &sa->key) != UBIFS_DATA_KEY && |
66576833 | 164 | key_type(c, &sb->key) != UBIFS_DATA_KEY); |
6eb61d58 | 165 | ubifs_assert(c, sa->type != UBIFS_DATA_NODE && |
ab87118d | 166 | sb->type != UBIFS_DATA_NODE); |
f10770f5 AB |
167 | |
168 | /* Inodes go before directory entries */ | |
ab87118d AB |
169 | if (sa->type == UBIFS_INO_NODE) { |
170 | if (sb->type == UBIFS_INO_NODE) | |
f10770f5 AB |
171 | return sb->len - sa->len; |
172 | return -1; | |
173 | } | |
ab87118d | 174 | if (sb->type == UBIFS_INO_NODE) |
f10770f5 AB |
175 | return 1; |
176 | ||
6eb61d58 | 177 | ubifs_assert(c, key_type(c, &sa->key) == UBIFS_DENT_KEY || |
66576833 | 178 | key_type(c, &sa->key) == UBIFS_XENT_KEY); |
6eb61d58 | 179 | ubifs_assert(c, key_type(c, &sb->key) == UBIFS_DENT_KEY || |
66576833 | 180 | key_type(c, &sb->key) == UBIFS_XENT_KEY); |
6eb61d58 | 181 | ubifs_assert(c, sa->type == UBIFS_DENT_NODE || |
ab87118d | 182 | sa->type == UBIFS_XENT_NODE); |
6eb61d58 | 183 | ubifs_assert(c, sb->type == UBIFS_DENT_NODE || |
ab87118d | 184 | sb->type == UBIFS_XENT_NODE); |
66576833 | 185 | |
f10770f5 AB |
186 | inuma = key_inum(c, &sa->key); |
187 | inumb = key_inum(c, &sb->key); | |
188 | ||
189 | if (inuma == inumb) { | |
190 | uint32_t hasha = key_hash(c, &sa->key); | |
191 | uint32_t hashb = key_hash(c, &sb->key); | |
192 | ||
193 | if (hasha <= hashb) | |
194 | return -1; | |
195 | } else if (inuma <= inumb) | |
196 | return -1; | |
197 | ||
198 | return 1; | |
199 | } | |
200 | ||
201 | /** | |
202 | * sort_nodes - sort nodes for GC. | |
1e51764a | 203 | * @c: UBIFS file-system description object |
f10770f5 AB |
204 | * @sleb: describes nodes to sort and contains the result on exit |
205 | * @nondata: contains non-data nodes on exit | |
206 | * @min: minimum node size is returned here | |
1e51764a | 207 | * |
f10770f5 AB |
208 | * This function sorts the list of inodes to garbage collect. First of all, it |
209 | * kills obsolete nodes and separates data and non-data nodes to the | |
210 | * @sleb->nodes and @nondata lists correspondingly. | |
1e51764a | 211 | * |
f10770f5 AB |
212 | * Data nodes are then sorted in block number order - this is important for |
213 | * bulk-read; data nodes with lower inode number go before data nodes with | |
214 | * higher inode number, and data nodes with lower block number go before data | |
215 | * nodes with higher block number; | |
1e51764a | 216 | * |
f10770f5 AB |
217 | * Non-data nodes are sorted as follows. |
218 | * o First go inode nodes - they are sorted in descending length order. | |
219 | * o Then go directory entry nodes - they are sorted in hash order, which | |
220 | * should supposedly optimize 'readdir()'. Direntry nodes with lower parent | |
221 | * inode number go before direntry nodes with higher parent inode number, | |
222 | * and direntry nodes with lower name hash values go before direntry nodes | |
223 | * with higher name hash values. | |
224 | * | |
225 | * This function returns zero in case of success and a negative error code in | |
226 | * case of failure. | |
1e51764a | 227 | */ |
f10770f5 AB |
228 | static int sort_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb, |
229 | struct list_head *nondata, int *min) | |
1e51764a | 230 | { |
3bb66b47 | 231 | int err; |
1e51764a | 232 | struct ubifs_scan_node *snod, *tmp; |
1e51764a | 233 | |
f10770f5 | 234 | *min = INT_MAX; |
1e51764a | 235 | |
f10770f5 AB |
236 | /* Separate data nodes and non-data nodes */ |
237 | list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) { | |
6eb61d58 | 238 | ubifs_assert(c, snod->type == UBIFS_INO_NODE || |
44ec83b8 AB |
239 | snod->type == UBIFS_DATA_NODE || |
240 | snod->type == UBIFS_DENT_NODE || | |
241 | snod->type == UBIFS_XENT_NODE || | |
6a98bc46 SH |
242 | snod->type == UBIFS_TRUN_NODE || |
243 | snod->type == UBIFS_AUTH_NODE); | |
44ec83b8 AB |
244 | |
245 | if (snod->type != UBIFS_INO_NODE && | |
246 | snod->type != UBIFS_DATA_NODE && | |
247 | snod->type != UBIFS_DENT_NODE && | |
248 | snod->type != UBIFS_XENT_NODE) { | |
249 | /* Probably truncation node, zap it */ | |
250 | list_del(&snod->list); | |
251 | kfree(snod); | |
252 | continue; | |
253 | } | |
254 | ||
6eb61d58 | 255 | ubifs_assert(c, key_type(c, &snod->key) == UBIFS_DATA_KEY || |
44ec83b8 AB |
256 | key_type(c, &snod->key) == UBIFS_INO_KEY || |
257 | key_type(c, &snod->key) == UBIFS_DENT_KEY || | |
258 | key_type(c, &snod->key) == UBIFS_XENT_KEY); | |
1e51764a AB |
259 | |
260 | err = ubifs_tnc_has_node(c, &snod->key, 0, sleb->lnum, | |
261 | snod->offs, 0); | |
262 | if (err < 0) | |
f10770f5 | 263 | return err; |
1e51764a | 264 | |
1e51764a AB |
265 | if (!err) { |
266 | /* The node is obsolete, remove it from the list */ | |
f10770f5 | 267 | list_del(&snod->list); |
1e51764a AB |
268 | kfree(snod); |
269 | continue; | |
270 | } | |
271 | ||
f10770f5 AB |
272 | if (snod->len < *min) |
273 | *min = snod->len; | |
274 | ||
275 | if (key_type(c, &snod->key) != UBIFS_DATA_KEY) | |
276 | list_move_tail(&snod->list, nondata); | |
1e51764a AB |
277 | } |
278 | ||
f10770f5 AB |
279 | /* Sort data and non-data nodes */ |
280 | list_sort(c, &sleb->nodes, &data_nodes_cmp); | |
281 | list_sort(c, nondata, &nondata_nodes_cmp); | |
3bb66b47 AB |
282 | |
283 | err = dbg_check_data_nodes_order(c, &sleb->nodes); | |
284 | if (err) | |
285 | return err; | |
286 | err = dbg_check_nondata_nodes_order(c, nondata); | |
287 | if (err) | |
288 | return err; | |
f10770f5 AB |
289 | return 0; |
290 | } | |
291 | ||
292 | /** | |
293 | * move_node - move a node. | |
294 | * @c: UBIFS file-system description object | |
295 | * @sleb: describes the LEB to move nodes from | |
296 | * @snod: the mode to move | |
297 | * @wbuf: write-buffer to move node to | |
298 | * | |
299 | * This function moves node @snod to @wbuf, changes TNC correspondingly, and | |
300 | * destroys @snod. Returns zero in case of success and a negative error code in | |
301 | * case of failure. | |
302 | */ | |
303 | static int move_node(struct ubifs_info *c, struct ubifs_scan_leb *sleb, | |
304 | struct ubifs_scan_node *snod, struct ubifs_wbuf *wbuf) | |
305 | { | |
306 | int err, new_lnum = wbuf->lnum, new_offs = wbuf->offs + wbuf->used; | |
307 | ||
308 | cond_resched(); | |
309 | err = ubifs_wbuf_write_nolock(wbuf, snod->node, snod->len); | |
310 | if (err) | |
311 | return err; | |
312 | ||
313 | err = ubifs_tnc_replace(c, &snod->key, sleb->lnum, | |
314 | snod->offs, new_lnum, new_offs, | |
315 | snod->len); | |
316 | list_del(&snod->list); | |
317 | kfree(snod); | |
318 | return err; | |
319 | } | |
320 | ||
321 | /** | |
322 | * move_nodes - move nodes. | |
323 | * @c: UBIFS file-system description object | |
324 | * @sleb: describes the LEB to move nodes from | |
325 | * | |
326 | * This function moves valid nodes from data LEB described by @sleb to the GC | |
327 | * journal head. This function returns zero in case of success, %-EAGAIN if | |
328 | * commit is required, and other negative error codes in case of other | |
329 | * failures. | |
330 | */ | |
331 | static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb) | |
332 | { | |
333 | int err, min; | |
334 | LIST_HEAD(nondata); | |
335 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
1e51764a AB |
336 | |
337 | if (wbuf->lnum == -1) { | |
338 | /* | |
339 | * The GC journal head is not set, because it is the first GC | |
340 | * invocation since mount. | |
341 | */ | |
342 | err = switch_gc_head(c); | |
343 | if (err) | |
f10770f5 | 344 | return err; |
1e51764a AB |
345 | } |
346 | ||
f10770f5 AB |
347 | err = sort_nodes(c, sleb, &nondata, &min); |
348 | if (err) | |
349 | goto out; | |
350 | ||
1e51764a AB |
351 | /* Write nodes to their new location. Use the first-fit strategy */ |
352 | while (1) { | |
6f06d96f | 353 | int avail, moved = 0; |
f10770f5 AB |
354 | struct ubifs_scan_node *snod, *tmp; |
355 | ||
356 | /* Move data nodes */ | |
357 | list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) { | |
6f06d96f SH |
358 | avail = c->leb_size - wbuf->offs - wbuf->used - |
359 | ubifs_auth_node_sz(c); | |
f10770f5 AB |
360 | if (snod->len > avail) |
361 | /* | |
362 | * Do not skip data nodes in order to optimize | |
363 | * bulk-read. | |
364 | */ | |
365 | break; | |
366 | ||
6f06d96f SH |
367 | err = ubifs_shash_update(c, c->jheads[GCHD].log_hash, |
368 | snod->node, snod->len); | |
369 | if (err) | |
370 | goto out; | |
371 | ||
f10770f5 AB |
372 | err = move_node(c, sleb, snod, wbuf); |
373 | if (err) | |
374 | goto out; | |
6f06d96f | 375 | moved = 1; |
f10770f5 | 376 | } |
1e51764a | 377 | |
f10770f5 AB |
378 | /* Move non-data nodes */ |
379 | list_for_each_entry_safe(snod, tmp, &nondata, list) { | |
6f06d96f SH |
380 | avail = c->leb_size - wbuf->offs - wbuf->used - |
381 | ubifs_auth_node_sz(c); | |
1e51764a AB |
382 | if (avail < min) |
383 | break; | |
384 | ||
f10770f5 AB |
385 | if (snod->len > avail) { |
386 | /* | |
387 | * Keep going only if this is an inode with | |
388 | * some data. Otherwise stop and switch the GC | |
389 | * head. IOW, we assume that data-less inode | |
390 | * nodes and direntry nodes are roughly of the | |
391 | * same size. | |
392 | */ | |
393 | if (key_type(c, &snod->key) == UBIFS_DENT_KEY || | |
394 | snod->len == UBIFS_INO_NODE_SZ) | |
395 | break; | |
1e51764a | 396 | continue; |
f10770f5 | 397 | } |
1e51764a | 398 | |
6f06d96f SH |
399 | err = ubifs_shash_update(c, c->jheads[GCHD].log_hash, |
400 | snod->node, snod->len); | |
401 | if (err) | |
402 | goto out; | |
403 | ||
f10770f5 | 404 | err = move_node(c, sleb, snod, wbuf); |
1e51764a AB |
405 | if (err) |
406 | goto out; | |
6f06d96f SH |
407 | moved = 1; |
408 | } | |
409 | ||
410 | if (ubifs_authenticated(c) && moved) { | |
411 | struct ubifs_auth_node *auth; | |
412 | ||
413 | auth = kmalloc(ubifs_auth_node_sz(c), GFP_NOFS); | |
414 | if (!auth) { | |
415 | err = -ENOMEM; | |
416 | goto out; | |
417 | } | |
418 | ||
419 | err = ubifs_prepare_auth_node(c, auth, | |
420 | c->jheads[GCHD].log_hash); | |
421 | if (err) { | |
422 | kfree(auth); | |
423 | goto out; | |
424 | } | |
425 | ||
426 | err = ubifs_wbuf_write_nolock(wbuf, auth, | |
427 | ubifs_auth_node_sz(c)); | |
428 | if (err) { | |
429 | kfree(auth); | |
430 | goto out; | |
431 | } | |
432 | ||
433 | ubifs_add_dirt(c, wbuf->lnum, ubifs_auth_node_sz(c)); | |
1e51764a AB |
434 | } |
435 | ||
f10770f5 | 436 | if (list_empty(&sleb->nodes) && list_empty(&nondata)) |
1e51764a AB |
437 | break; |
438 | ||
439 | /* | |
440 | * Waste the rest of the space in the LEB and switch to the | |
441 | * next LEB. | |
442 | */ | |
443 | err = switch_gc_head(c); | |
444 | if (err) | |
445 | goto out; | |
446 | } | |
447 | ||
448 | return 0; | |
449 | ||
450 | out: | |
f10770f5 | 451 | list_splice_tail(&nondata, &sleb->nodes); |
1e51764a AB |
452 | return err; |
453 | } | |
454 | ||
455 | /** | |
456 | * gc_sync_wbufs - sync write-buffers for GC. | |
457 | * @c: UBIFS file-system description object | |
458 | * | |
459 | * We must guarantee that obsoleting nodes are on flash. Unfortunately they may | |
460 | * be in a write-buffer instead. That is, a node could be written to a | |
461 | * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is | |
462 | * erased before the write-buffer is sync'd and then there is an unclean | |
463 | * unmount, then an existing node is lost. To avoid this, we sync all | |
464 | * write-buffers. | |
465 | * | |
466 | * This function returns %0 on success or a negative error code on failure. | |
467 | */ | |
468 | static int gc_sync_wbufs(struct ubifs_info *c) | |
469 | { | |
470 | int err, i; | |
471 | ||
472 | for (i = 0; i < c->jhead_cnt; i++) { | |
473 | if (i == GCHD) | |
474 | continue; | |
475 | err = ubifs_wbuf_sync(&c->jheads[i].wbuf); | |
476 | if (err) | |
477 | return err; | |
478 | } | |
479 | return 0; | |
480 | } | |
481 | ||
482 | /** | |
483 | * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock. | |
484 | * @c: UBIFS file-system description object | |
485 | * @lp: describes the LEB to garbage collect | |
486 | * | |
487 | * This function garbage-collects an LEB and returns one of the @LEB_FREED, | |
488 | * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is | |
489 | * required, and other negative error codes in case of failures. | |
490 | */ | |
491 | int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp) | |
492 | { | |
493 | struct ubifs_scan_leb *sleb; | |
494 | struct ubifs_scan_node *snod; | |
495 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
496 | int err = 0, lnum = lp->lnum; | |
497 | ||
6eb61d58 | 498 | ubifs_assert(c, c->gc_lnum != -1 || wbuf->offs + wbuf->used == 0 || |
1e51764a | 499 | c->need_recovery); |
6eb61d58 RW |
500 | ubifs_assert(c, c->gc_lnum != lnum); |
501 | ubifs_assert(c, wbuf->lnum != lnum); | |
1e51764a | 502 | |
2405f594 AB |
503 | if (lp->free + lp->dirty == c->leb_size) { |
504 | /* Special case - a free LEB */ | |
505 | dbg_gc("LEB %d is free, return it", lp->lnum); | |
6eb61d58 | 506 | ubifs_assert(c, !(lp->flags & LPROPS_INDEX)); |
2405f594 AB |
507 | |
508 | if (lp->free != c->leb_size) { | |
509 | /* | |
510 | * Write buffers must be sync'd before unmapping | |
511 | * freeable LEBs, because one of them may contain data | |
312c39bd | 512 | * which obsoletes something in 'lp->lnum'. |
2405f594 AB |
513 | */ |
514 | err = gc_sync_wbufs(c); | |
515 | if (err) | |
516 | return err; | |
517 | err = ubifs_change_one_lp(c, lp->lnum, c->leb_size, | |
518 | 0, 0, 0, 0); | |
519 | if (err) | |
520 | return err; | |
521 | } | |
522 | err = ubifs_leb_unmap(c, lp->lnum); | |
523 | if (err) | |
524 | return err; | |
525 | ||
526 | if (c->gc_lnum == -1) { | |
527 | c->gc_lnum = lnum; | |
528 | return LEB_RETAINED; | |
529 | } | |
530 | ||
531 | return LEB_FREED; | |
532 | } | |
533 | ||
1e51764a AB |
534 | /* |
535 | * We scan the entire LEB even though we only really need to scan up to | |
536 | * (c->leb_size - lp->free). | |
537 | */ | |
348709ba | 538 | sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0); |
1e51764a AB |
539 | if (IS_ERR(sleb)) |
540 | return PTR_ERR(sleb); | |
541 | ||
6eb61d58 | 542 | ubifs_assert(c, !list_empty(&sleb->nodes)); |
1e51764a AB |
543 | snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list); |
544 | ||
545 | if (snod->type == UBIFS_IDX_NODE) { | |
546 | struct ubifs_gced_idx_leb *idx_gc; | |
547 | ||
548 | dbg_gc("indexing LEB %d (free %d, dirty %d)", | |
549 | lnum, lp->free, lp->dirty); | |
550 | list_for_each_entry(snod, &sleb->nodes, list) { | |
551 | struct ubifs_idx_node *idx = snod->node; | |
552 | int level = le16_to_cpu(idx->level); | |
553 | ||
6eb61d58 | 554 | ubifs_assert(c, snod->type == UBIFS_IDX_NODE); |
1e51764a AB |
555 | key_read(c, ubifs_idx_key(c, idx), &snod->key); |
556 | err = ubifs_dirty_idx_node(c, &snod->key, level, lnum, | |
557 | snod->offs); | |
558 | if (err) | |
559 | goto out; | |
560 | } | |
561 | ||
562 | idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS); | |
563 | if (!idx_gc) { | |
564 | err = -ENOMEM; | |
565 | goto out; | |
566 | } | |
567 | ||
568 | idx_gc->lnum = lnum; | |
569 | idx_gc->unmap = 0; | |
570 | list_add(&idx_gc->list, &c->idx_gc); | |
571 | ||
572 | /* | |
573 | * Don't release the LEB until after the next commit, because | |
227c75c9 | 574 | * it may contain data which is needed for recovery. So |
1e51764a AB |
575 | * although we freed this LEB, it will become usable only after |
576 | * the commit. | |
577 | */ | |
578 | err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, | |
579 | LPROPS_INDEX, 1); | |
580 | if (err) | |
581 | goto out; | |
582 | err = LEB_FREED_IDX; | |
583 | } else { | |
584 | dbg_gc("data LEB %d (free %d, dirty %d)", | |
585 | lnum, lp->free, lp->dirty); | |
586 | ||
587 | err = move_nodes(c, sleb); | |
588 | if (err) | |
6dcfac4f | 589 | goto out_inc_seq; |
1e51764a AB |
590 | |
591 | err = gc_sync_wbufs(c); | |
592 | if (err) | |
6dcfac4f | 593 | goto out_inc_seq; |
1e51764a AB |
594 | |
595 | err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0); | |
596 | if (err) | |
6dcfac4f | 597 | goto out_inc_seq; |
1e51764a | 598 | |
601c0bc4 AH |
599 | /* Allow for races with TNC */ |
600 | c->gced_lnum = lnum; | |
601 | smp_wmb(); | |
602 | c->gc_seq += 1; | |
603 | smp_wmb(); | |
604 | ||
1e51764a AB |
605 | if (c->gc_lnum == -1) { |
606 | c->gc_lnum = lnum; | |
607 | err = LEB_RETAINED; | |
608 | } else { | |
609 | err = ubifs_wbuf_sync_nolock(wbuf); | |
610 | if (err) | |
611 | goto out; | |
612 | ||
613 | err = ubifs_leb_unmap(c, lnum); | |
614 | if (err) | |
615 | goto out; | |
616 | ||
617 | err = LEB_FREED; | |
618 | } | |
619 | } | |
620 | ||
621 | out: | |
622 | ubifs_scan_destroy(sleb); | |
623 | return err; | |
6dcfac4f AH |
624 | |
625 | out_inc_seq: | |
626 | /* We may have moved at least some nodes so allow for races with TNC */ | |
627 | c->gced_lnum = lnum; | |
628 | smp_wmb(); | |
629 | c->gc_seq += 1; | |
630 | smp_wmb(); | |
631 | goto out; | |
1e51764a AB |
632 | } |
633 | ||
634 | /** | |
635 | * ubifs_garbage_collect - UBIFS garbage collector. | |
636 | * @c: UBIFS file-system description object | |
637 | * @anyway: do GC even if there are free LEBs | |
638 | * | |
639 | * This function does out-of-place garbage collection. The return codes are: | |
640 | * o positive LEB number if the LEB has been freed and may be used; | |
641 | * o %-EAGAIN if the caller has to run commit; | |
642 | * o %-ENOSPC if GC failed to make any progress; | |
643 | * o other negative error codes in case of other errors. | |
644 | * | |
645 | * Garbage collector writes data to the journal when GC'ing data LEBs, and just | |
646 | * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point | |
647 | * commit may be required. But commit cannot be run from inside GC, because the | |
648 | * caller might be holding the commit lock, so %-EAGAIN is returned instead; | |
649 | * And this error code means that the caller has to run commit, and re-run GC | |
650 | * if there is still no free space. | |
651 | * | |
652 | * There are many reasons why this function may return %-EAGAIN: | |
653 | * o the log is full and there is no space to write an LEB reference for | |
654 | * @c->gc_lnum; | |
655 | * o the journal is too large and exceeds size limitations; | |
656 | * o GC moved indexing LEBs, but they can be used only after the commit; | |
657 | * o the shrinker fails to find clean znodes to free and requests the commit; | |
658 | * o etc. | |
659 | * | |
660 | * Note, if the file-system is close to be full, this function may return | |
661 | * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of | |
662 | * the function. E.g., this happens if the limits on the journal size are too | |
663 | * tough and GC writes too much to the journal before an LEB is freed. This | |
664 | * might also mean that the journal is too large, and the TNC becomes to big, | |
665 | * so that the shrinker is constantly called, finds not clean znodes to free, | |
666 | * and requests commit. Well, this may also happen if the journal is all right, | |
667 | * but another kernel process consumes too much memory. Anyway, infinite | |
668 | * %-EAGAIN may happen, but in some extreme/misconfiguration cases. | |
669 | */ | |
670 | int ubifs_garbage_collect(struct ubifs_info *c, int anyway) | |
671 | { | |
672 | int i, err, ret, min_space = c->dead_wm; | |
673 | struct ubifs_lprops lp; | |
674 | struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; | |
675 | ||
676 | ubifs_assert_cmt_locked(c); | |
6eb61d58 | 677 | ubifs_assert(c, !c->ro_media && !c->ro_mount); |
1e51764a AB |
678 | |
679 | if (ubifs_gc_should_commit(c)) | |
680 | return -EAGAIN; | |
681 | ||
682 | mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); | |
683 | ||
2680d722 | 684 | if (c->ro_error) { |
1e51764a AB |
685 | ret = -EROFS; |
686 | goto out_unlock; | |
687 | } | |
688 | ||
689 | /* We expect the write-buffer to be empty on entry */ | |
6eb61d58 | 690 | ubifs_assert(c, !wbuf->used); |
1e51764a AB |
691 | |
692 | for (i = 0; ; i++) { | |
e71d1a59 | 693 | int space_before, space_after; |
1e51764a | 694 | |
88618fee BL |
695 | /* Maybe continue after find and break before find */ |
696 | lp.lnum = -1; | |
697 | ||
1e51764a AB |
698 | cond_resched(); |
699 | ||
700 | /* Give the commit an opportunity to run */ | |
701 | if (ubifs_gc_should_commit(c)) { | |
702 | ret = -EAGAIN; | |
703 | break; | |
704 | } | |
705 | ||
706 | if (i > SOFT_LEBS_LIMIT && !list_empty(&c->idx_gc)) { | |
707 | /* | |
708 | * We've done enough iterations. Indexing LEBs were | |
709 | * moved and will be available after the commit. | |
710 | */ | |
711 | dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN"); | |
712 | ubifs_commit_required(c); | |
713 | ret = -EAGAIN; | |
714 | break; | |
715 | } | |
716 | ||
717 | if (i > HARD_LEBS_LIMIT) { | |
718 | /* | |
719 | * We've moved too many LEBs and have not made | |
720 | * progress, give up. | |
721 | */ | |
722 | dbg_gc("hard limit, -ENOSPC"); | |
723 | ret = -ENOSPC; | |
724 | break; | |
725 | } | |
726 | ||
727 | /* | |
728 | * Empty and freeable LEBs can turn up while we waited for | |
729 | * the wbuf lock, or while we have been running GC. In that | |
730 | * case, we should just return one of those instead of | |
731 | * continuing to GC dirty LEBs. Hence we request | |
732 | * 'ubifs_find_dirty_leb()' to return an empty LEB if it can. | |
733 | */ | |
734 | ret = ubifs_find_dirty_leb(c, &lp, min_space, anyway ? 0 : 1); | |
735 | if (ret) { | |
736 | if (ret == -ENOSPC) | |
737 | dbg_gc("no more dirty LEBs"); | |
738 | break; | |
739 | } | |
740 | ||
79fda517 AB |
741 | dbg_gc("found LEB %d: free %d, dirty %d, sum %d (min. space %d)", |
742 | lp.lnum, lp.free, lp.dirty, lp.free + lp.dirty, | |
743 | min_space); | |
1e51764a | 744 | |
1e51764a AB |
745 | space_before = c->leb_size - wbuf->offs - wbuf->used; |
746 | if (wbuf->lnum == -1) | |
747 | space_before = 0; | |
748 | ||
749 | ret = ubifs_garbage_collect_leb(c, &lp); | |
750 | if (ret < 0) { | |
efe1881f | 751 | if (ret == -EAGAIN) { |
1e51764a | 752 | /* |
efe1881f AB |
753 | * This is not error, so we have to return the |
754 | * LEB to lprops. But if 'ubifs_return_leb()' | |
755 | * fails, its failure code is propagated to the | |
756 | * caller instead of the original '-EAGAIN'. | |
1e51764a AB |
757 | */ |
758 | err = ubifs_return_leb(c, lp.lnum); | |
50cb4373 | 759 | if (err) { |
1e51764a | 760 | ret = err; |
50cb4373 BL |
761 | /* |
762 | * An LEB may always be "taken", | |
763 | * so setting ubifs to read-only, | |
764 | * and then executing sync wbuf will | |
765 | * return -EROFS and enter the "out" | |
766 | * error branch. | |
767 | */ | |
768 | ubifs_ro_mode(c, ret); | |
769 | } | |
0d765021 BL |
770 | /* Maybe double return LEB if goto out */ |
771 | lp.lnum = -1; | |
1e51764a AB |
772 | break; |
773 | } | |
774 | goto out; | |
775 | } | |
776 | ||
777 | if (ret == LEB_FREED) { | |
778 | /* An LEB has been freed and is ready for use */ | |
779 | dbg_gc("LEB %d freed, return", lp.lnum); | |
780 | ret = lp.lnum; | |
781 | break; | |
782 | } | |
783 | ||
784 | if (ret == LEB_FREED_IDX) { | |
785 | /* | |
786 | * This was an indexing LEB and it cannot be | |
787 | * immediately used. And instead of requesting the | |
788 | * commit straight away, we try to garbage collect some | |
789 | * more. | |
790 | */ | |
791 | dbg_gc("indexing LEB %d freed, continue", lp.lnum); | |
792 | continue; | |
793 | } | |
794 | ||
6eb61d58 | 795 | ubifs_assert(c, ret == LEB_RETAINED); |
1e51764a AB |
796 | space_after = c->leb_size - wbuf->offs - wbuf->used; |
797 | dbg_gc("LEB %d retained, freed %d bytes", lp.lnum, | |
798 | space_after - space_before); | |
799 | ||
800 | if (space_after > space_before) { | |
801 | /* GC makes progress, keep working */ | |
802 | min_space >>= 1; | |
803 | if (min_space < c->dead_wm) | |
804 | min_space = c->dead_wm; | |
805 | continue; | |
806 | } | |
807 | ||
808 | dbg_gc("did not make progress"); | |
809 | ||
810 | /* | |
811 | * GC moved an LEB bud have not done any progress. This means | |
812 | * that the previous GC head LEB contained too few free space | |
813 | * and the LEB which was GC'ed contained only large nodes which | |
814 | * did not fit that space. | |
815 | * | |
816 | * We can do 2 things: | |
817 | * 1. pick another LEB in a hope it'll contain a small node | |
818 | * which will fit the space we have at the end of current GC | |
819 | * head LEB, but there is no guarantee, so we try this out | |
820 | * unless we have already been working for too long; | |
821 | * 2. request an LEB with more dirty space, which will force | |
822 | * 'ubifs_find_dirty_leb()' to start scanning the lprops | |
823 | * table, instead of just picking one from the heap | |
824 | * (previously it already picked the dirtiest LEB). | |
825 | */ | |
826 | if (i < SOFT_LEBS_LIMIT) { | |
827 | dbg_gc("try again"); | |
828 | continue; | |
829 | } | |
830 | ||
831 | min_space <<= 1; | |
832 | if (min_space > c->dark_wm) | |
833 | min_space = c->dark_wm; | |
834 | dbg_gc("set min. space to %d", min_space); | |
835 | } | |
836 | ||
837 | if (ret == -ENOSPC && !list_empty(&c->idx_gc)) { | |
838 | dbg_gc("no space, some index LEBs GC'ed, -EAGAIN"); | |
839 | ubifs_commit_required(c); | |
840 | ret = -EAGAIN; | |
841 | } | |
842 | ||
843 | err = ubifs_wbuf_sync_nolock(wbuf); | |
844 | if (!err) | |
845 | err = ubifs_leb_unmap(c, c->gc_lnum); | |
846 | if (err) { | |
847 | ret = err; | |
848 | goto out; | |
849 | } | |
850 | out_unlock: | |
851 | mutex_unlock(&wbuf->io_mutex); | |
852 | return ret; | |
853 | ||
854 | out: | |
6eb61d58 RW |
855 | ubifs_assert(c, ret < 0); |
856 | ubifs_assert(c, ret != -ENOSPC && ret != -EAGAIN); | |
1e51764a | 857 | ubifs_wbuf_sync_nolock(wbuf); |
5ffef88f | 858 | ubifs_ro_mode(c, ret); |
1e51764a | 859 | mutex_unlock(&wbuf->io_mutex); |
88618fee BL |
860 | if (lp.lnum != -1) |
861 | ubifs_return_leb(c, lp.lnum); | |
1e51764a AB |
862 | return ret; |
863 | } | |
864 | ||
865 | /** | |
866 | * ubifs_gc_start_commit - garbage collection at start of commit. | |
867 | * @c: UBIFS file-system description object | |
868 | * | |
869 | * If a LEB has only dirty and free space, then we may safely unmap it and make | |
870 | * it free. Note, we cannot do this with indexing LEBs because dirty space may | |
871 | * correspond index nodes that are required for recovery. In that case, the | |
872 | * LEB cannot be unmapped until after the next commit. | |
873 | * | |
874 | * This function returns %0 upon success and a negative error code upon failure. | |
875 | */ | |
876 | int ubifs_gc_start_commit(struct ubifs_info *c) | |
877 | { | |
878 | struct ubifs_gced_idx_leb *idx_gc; | |
879 | const struct ubifs_lprops *lp; | |
880 | int err = 0, flags; | |
881 | ||
882 | ubifs_get_lprops(c); | |
883 | ||
884 | /* | |
885 | * Unmap (non-index) freeable LEBs. Note that recovery requires that all | |
886 | * wbufs are sync'd before this, which is done in 'do_commit()'. | |
887 | */ | |
888 | while (1) { | |
889 | lp = ubifs_fast_find_freeable(c); | |
1e51764a AB |
890 | if (!lp) |
891 | break; | |
6eb61d58 RW |
892 | ubifs_assert(c, !(lp->flags & LPROPS_TAKEN)); |
893 | ubifs_assert(c, !(lp->flags & LPROPS_INDEX)); | |
1e51764a AB |
894 | err = ubifs_leb_unmap(c, lp->lnum); |
895 | if (err) | |
896 | goto out; | |
897 | lp = ubifs_change_lp(c, lp, c->leb_size, 0, lp->flags, 0); | |
8d47aef4 | 898 | if (IS_ERR(lp)) { |
1e51764a AB |
899 | err = PTR_ERR(lp); |
900 | goto out; | |
901 | } | |
6eb61d58 RW |
902 | ubifs_assert(c, !(lp->flags & LPROPS_TAKEN)); |
903 | ubifs_assert(c, !(lp->flags & LPROPS_INDEX)); | |
1e51764a AB |
904 | } |
905 | ||
906 | /* Mark GC'd index LEBs OK to unmap after this commit finishes */ | |
907 | list_for_each_entry(idx_gc, &c->idx_gc, list) | |
908 | idx_gc->unmap = 1; | |
909 | ||
910 | /* Record index freeable LEBs for unmapping after commit */ | |
911 | while (1) { | |
912 | lp = ubifs_fast_find_frdi_idx(c); | |
8d47aef4 | 913 | if (IS_ERR(lp)) { |
1e51764a AB |
914 | err = PTR_ERR(lp); |
915 | goto out; | |
916 | } | |
917 | if (!lp) | |
918 | break; | |
919 | idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS); | |
920 | if (!idx_gc) { | |
921 | err = -ENOMEM; | |
922 | goto out; | |
923 | } | |
6eb61d58 RW |
924 | ubifs_assert(c, !(lp->flags & LPROPS_TAKEN)); |
925 | ubifs_assert(c, lp->flags & LPROPS_INDEX); | |
1e51764a AB |
926 | /* Don't release the LEB until after the next commit */ |
927 | flags = (lp->flags | LPROPS_TAKEN) ^ LPROPS_INDEX; | |
928 | lp = ubifs_change_lp(c, lp, c->leb_size, 0, flags, 1); | |
8d47aef4 | 929 | if (IS_ERR(lp)) { |
1e51764a AB |
930 | err = PTR_ERR(lp); |
931 | kfree(idx_gc); | |
932 | goto out; | |
933 | } | |
6eb61d58 RW |
934 | ubifs_assert(c, lp->flags & LPROPS_TAKEN); |
935 | ubifs_assert(c, !(lp->flags & LPROPS_INDEX)); | |
1e51764a AB |
936 | idx_gc->lnum = lp->lnum; |
937 | idx_gc->unmap = 1; | |
938 | list_add(&idx_gc->list, &c->idx_gc); | |
939 | } | |
940 | out: | |
941 | ubifs_release_lprops(c); | |
942 | return err; | |
943 | } | |
944 | ||
945 | /** | |
946 | * ubifs_gc_end_commit - garbage collection at end of commit. | |
947 | * @c: UBIFS file-system description object | |
948 | * | |
949 | * This function completes out-of-place garbage collection of index LEBs. | |
950 | */ | |
951 | int ubifs_gc_end_commit(struct ubifs_info *c) | |
952 | { | |
953 | struct ubifs_gced_idx_leb *idx_gc, *tmp; | |
954 | struct ubifs_wbuf *wbuf; | |
955 | int err = 0; | |
956 | ||
957 | wbuf = &c->jheads[GCHD].wbuf; | |
958 | mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); | |
959 | list_for_each_entry_safe(idx_gc, tmp, &c->idx_gc, list) | |
960 | if (idx_gc->unmap) { | |
961 | dbg_gc("LEB %d", idx_gc->lnum); | |
962 | err = ubifs_leb_unmap(c, idx_gc->lnum); | |
963 | if (err) | |
964 | goto out; | |
965 | err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC, | |
966 | LPROPS_NC, 0, LPROPS_TAKEN, -1); | |
967 | if (err) | |
968 | goto out; | |
969 | list_del(&idx_gc->list); | |
970 | kfree(idx_gc); | |
971 | } | |
972 | out: | |
973 | mutex_unlock(&wbuf->io_mutex); | |
974 | return err; | |
975 | } | |
976 | ||
977 | /** | |
978 | * ubifs_destroy_idx_gc - destroy idx_gc list. | |
979 | * @c: UBIFS file-system description object | |
980 | * | |
b466f17d AH |
981 | * This function destroys the @c->idx_gc list. It is called when unmounting |
982 | * so locks are not needed. Returns zero in case of success and a negative | |
983 | * error code in case of failure. | |
1e51764a | 984 | */ |
b466f17d | 985 | void ubifs_destroy_idx_gc(struct ubifs_info *c) |
1e51764a AB |
986 | { |
987 | while (!list_empty(&c->idx_gc)) { | |
988 | struct ubifs_gced_idx_leb *idx_gc; | |
989 | ||
990 | idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, | |
991 | list); | |
b466f17d | 992 | c->idx_gc_cnt -= 1; |
1e51764a AB |
993 | list_del(&idx_gc->list); |
994 | kfree(idx_gc); | |
995 | } | |
1e51764a AB |
996 | } |
997 | ||
998 | /** | |
999 | * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list. | |
1000 | * @c: UBIFS file-system description object | |
1001 | * | |
1002 | * Called during start commit so locks are not needed. | |
1003 | */ | |
1004 | int ubifs_get_idx_gc_leb(struct ubifs_info *c) | |
1005 | { | |
1006 | struct ubifs_gced_idx_leb *idx_gc; | |
1007 | int lnum; | |
1008 | ||
1009 | if (list_empty(&c->idx_gc)) | |
1010 | return -ENOSPC; | |
1011 | idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, list); | |
1012 | lnum = idx_gc->lnum; | |
1013 | /* c->idx_gc_cnt is updated by the caller when lprops are updated */ | |
1014 | list_del(&idx_gc->list); | |
1015 | kfree(idx_gc); | |
1016 | return lnum; | |
1017 | } |