1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2016-present, Facebook, Inc.
4 * All rights reserved.
5 *
6 */
7
8 #include <linux/bio.h>
9 #include <linux/bitmap.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/mm.h>
14 #include <linux/sched/mm.h>
15 #include <linux/pagemap.h>
16 #include <linux/refcount.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/zstd.h>
20 #include "misc.h"
21 #include "fs.h"
22 #include "btrfs_inode.h"
23 #include "compression.h"
24 #include "super.h"
25
26 #define ZSTD_BTRFS_MAX_WINDOWLOG 17
27 #define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
28 #define ZSTD_BTRFS_DEFAULT_LEVEL 3
29 #define ZSTD_BTRFS_MIN_LEVEL -15
30 #define ZSTD_BTRFS_MAX_LEVEL 15
31 /* 307s to avoid pathologically clashing with transaction commit */
32 #define ZSTD_BTRFS_RECLAIM_JIFFIES (307 * HZ)
33
zstd_get_btrfs_parameters(int level,size_t src_len)34 static zstd_parameters zstd_get_btrfs_parameters(int level,
35 size_t src_len)
36 {
37 zstd_parameters params = zstd_get_params(level, src_len);
38
39 if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
40 params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
41 WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
42 return params;
43 }
44
45 struct workspace {
46 void *mem;
47 size_t size;
48 char *buf;
49 int level;
50 int req_level;
51 unsigned long last_used; /* jiffies */
52 struct list_head list;
53 struct list_head lru_list;
54 zstd_in_buffer in_buf;
55 zstd_out_buffer out_buf;
56 zstd_parameters params;
57 };
58
59 /*
60 * Zstd Workspace Management
61 *
62 * Zstd workspaces have different memory requirements depending on the level.
63 * The zstd workspaces are managed by having individual lists for each level
64 * and a global lru. Forward progress is maintained by protecting a max level
65 * workspace.
66 *
67 * Getting a workspace is done by using the bitmap to identify the levels that
68 * have available workspaces and scans up. This lets us recycle higher level
69 * workspaces because of the monotonic memory guarantee. A workspace's
70 * last_used is only updated if it is being used by the corresponding memory
71 * level. Putting a workspace involves adding it back to the appropriate places
72 * and adding it back to the lru if necessary.
73 *
74 * A timer is used to reclaim workspaces if they have not been used for
75 * ZSTD_BTRFS_RECLAIM_JIFFIES. This helps keep only active workspaces around.
76 * The upper bound is provided by the workqueue limit which is 2 (percpu limit).
77 */
78
79 struct zstd_workspace_manager {
80 const struct btrfs_compress_op *ops;
81 spinlock_t lock;
82 struct list_head lru_list;
83 struct list_head idle_ws[ZSTD_BTRFS_MAX_LEVEL];
84 unsigned long active_map;
85 wait_queue_head_t wait;
86 struct timer_list timer;
87 };
88
89 static struct zstd_workspace_manager wsm;
90
91 static size_t zstd_ws_mem_sizes[ZSTD_BTRFS_MAX_LEVEL];
92
list_to_workspace(struct list_head * list)93 static inline struct workspace *list_to_workspace(struct list_head *list)
94 {
95 return container_of(list, struct workspace, list);
96 }
97
clip_level(int level)98 static inline int clip_level(int level)
99 {
100 return max(0, level - 1);
101 }
102
103 /*
104 * Timer callback to free unused workspaces.
105 *
106 * @t: timer
107 *
108 * This scans the lru_list and attempts to reclaim any workspace that hasn't
109 * been used for ZSTD_BTRFS_RECLAIM_JIFFIES.
110 *
111 * The context is softirq and does not need the _bh locking primitives.
112 */
zstd_reclaim_timer_fn(struct timer_list * timer)113 static void zstd_reclaim_timer_fn(struct timer_list *timer)
114 {
115 unsigned long reclaim_threshold = jiffies - ZSTD_BTRFS_RECLAIM_JIFFIES;
116 struct list_head *pos, *next;
117
118 ASSERT(timer == &wsm.timer);
119
120 spin_lock(&wsm.lock);
121
122 if (list_empty(&wsm.lru_list)) {
123 spin_unlock(&wsm.lock);
124 return;
125 }
126
127 list_for_each_prev_safe(pos, next, &wsm.lru_list) {
128 struct workspace *victim = container_of(pos, struct workspace,
129 lru_list);
130 int level;
131
132 if (time_after(victim->last_used, reclaim_threshold))
133 break;
134
135 /* workspace is in use */
136 if (victim->req_level)
137 continue;
138
139 level = victim->level;
140 list_del(&victim->lru_list);
141 list_del(&victim->list);
142 zstd_free_workspace(&victim->list);
143
144 if (list_empty(&wsm.idle_ws[level]))
145 clear_bit(level, &wsm.active_map);
146
147 }
148
149 if (!list_empty(&wsm.lru_list))
150 mod_timer(&wsm.timer, jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES);
151
152 spin_unlock(&wsm.lock);
153 }
154
155 /*
156 * Calculate monotonic memory bounds.
157 *
158 * It is possible based on the level configurations that a higher level
159 * workspace uses less memory than a lower level workspace. In order to reuse
160 * workspaces, this must be made a monotonic relationship. This precomputes
161 * the required memory for each level and enforces the monotonicity between
162 * level and memory required.
163 */
zstd_calc_ws_mem_sizes(void)164 static void zstd_calc_ws_mem_sizes(void)
165 {
166 size_t max_size = 0;
167 int level;
168
169 for (level = ZSTD_BTRFS_MIN_LEVEL; level <= ZSTD_BTRFS_MAX_LEVEL; level++) {
170 if (level == 0)
171 continue;
172 zstd_parameters params =
173 zstd_get_btrfs_parameters(level, ZSTD_BTRFS_MAX_INPUT);
174 size_t level_size =
175 max_t(size_t,
176 zstd_cstream_workspace_bound(¶ms.cParams),
177 zstd_dstream_workspace_bound(ZSTD_BTRFS_MAX_INPUT));
178
179 max_size = max_t(size_t, max_size, level_size);
180 /* Use level 1 workspace size for all the fast mode negative levels. */
181 zstd_ws_mem_sizes[clip_level(level)] = max_size;
182 }
183 }
184
zstd_init_workspace_manager(void)185 void zstd_init_workspace_manager(void)
186 {
187 struct list_head *ws;
188 int i;
189
190 zstd_calc_ws_mem_sizes();
191
192 wsm.ops = &btrfs_zstd_compress;
193 spin_lock_init(&wsm.lock);
194 init_waitqueue_head(&wsm.wait);
195 timer_setup(&wsm.timer, zstd_reclaim_timer_fn, 0);
196
197 INIT_LIST_HEAD(&wsm.lru_list);
198 for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++)
199 INIT_LIST_HEAD(&wsm.idle_ws[i]);
200
201 ws = zstd_alloc_workspace(ZSTD_BTRFS_MAX_LEVEL);
202 if (IS_ERR(ws)) {
203 pr_warn(
204 "BTRFS: cannot preallocate zstd compression workspace\n");
205 } else {
206 set_bit(ZSTD_BTRFS_MAX_LEVEL - 1, &wsm.active_map);
207 list_add(ws, &wsm.idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1]);
208 }
209 }
210
zstd_cleanup_workspace_manager(void)211 void zstd_cleanup_workspace_manager(void)
212 {
213 struct workspace *workspace;
214 int i;
215
216 spin_lock_bh(&wsm.lock);
217 for (i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) {
218 while (!list_empty(&wsm.idle_ws[i])) {
219 workspace = container_of(wsm.idle_ws[i].next,
220 struct workspace, list);
221 list_del(&workspace->list);
222 list_del(&workspace->lru_list);
223 zstd_free_workspace(&workspace->list);
224 }
225 }
226 spin_unlock_bh(&wsm.lock);
227
228 del_timer_sync(&wsm.timer);
229 }
230
231 /*
232 * Find workspace for given level.
233 *
234 * @level: compression level
235 *
236 * This iterates over the set bits in the active_map beginning at the requested
237 * compression level. This lets us utilize already allocated workspaces before
238 * allocating a new one. If the workspace is of a larger size, it is used, but
239 * the place in the lru_list and last_used times are not updated. This is to
240 * offer the opportunity to reclaim the workspace in favor of allocating an
241 * appropriately sized one in the future.
242 */
zstd_find_workspace(int level)243 static struct list_head *zstd_find_workspace(int level)
244 {
245 struct list_head *ws;
246 struct workspace *workspace;
247 int i = clip_level(level);
248
249 spin_lock_bh(&wsm.lock);
250 for_each_set_bit_from(i, &wsm.active_map, ZSTD_BTRFS_MAX_LEVEL) {
251 if (!list_empty(&wsm.idle_ws[i])) {
252 ws = wsm.idle_ws[i].next;
253 workspace = list_to_workspace(ws);
254 list_del_init(ws);
255 /* keep its place if it's a lower level using this */
256 workspace->req_level = level;
257 if (clip_level(level) == workspace->level)
258 list_del(&workspace->lru_list);
259 if (list_empty(&wsm.idle_ws[i]))
260 clear_bit(i, &wsm.active_map);
261 spin_unlock_bh(&wsm.lock);
262 return ws;
263 }
264 }
265 spin_unlock_bh(&wsm.lock);
266
267 return NULL;
268 }
269
270 /*
271 * Zstd get_workspace for level.
272 *
273 * @level: compression level
274 *
275 * If @level is 0, then any compression level can be used. Therefore, we begin
276 * scanning from 1. We first scan through possible workspaces and then after
277 * attempt to allocate a new workspace. If we fail to allocate one due to
278 * memory pressure, go to sleep waiting for the max level workspace to free up.
279 */
zstd_get_workspace(int level)280 struct list_head *zstd_get_workspace(int level)
281 {
282 struct list_head *ws;
283 unsigned int nofs_flag;
284
285 /* level == 0 means we can use any workspace */
286 if (!level)
287 level = 1;
288
289 again:
290 ws = zstd_find_workspace(level);
291 if (ws)
292 return ws;
293
294 nofs_flag = memalloc_nofs_save();
295 ws = zstd_alloc_workspace(level);
296 memalloc_nofs_restore(nofs_flag);
297
298 if (IS_ERR(ws)) {
299 DEFINE_WAIT(wait);
300
301 prepare_to_wait(&wsm.wait, &wait, TASK_UNINTERRUPTIBLE);
302 schedule();
303 finish_wait(&wsm.wait, &wait);
304
305 goto again;
306 }
307
308 return ws;
309 }
310
311 /*
312 * Zstd put_workspace.
313 *
314 * @ws: list_head for the workspace
315 *
316 * When putting back a workspace, we only need to update the LRU if we are of
317 * the requested compression level. Here is where we continue to protect the
318 * max level workspace or update last_used accordingly. If the reclaim timer
319 * isn't set, it is also set here. Only the max level workspace tries and wakes
320 * up waiting workspaces.
321 */
zstd_put_workspace(struct list_head * ws)322 void zstd_put_workspace(struct list_head *ws)
323 {
324 struct workspace *workspace = list_to_workspace(ws);
325
326 spin_lock_bh(&wsm.lock);
327
328 /* A node is only taken off the lru if we are the corresponding level */
329 if (clip_level(workspace->req_level) == workspace->level) {
330 /* Hide a max level workspace from reclaim */
331 if (list_empty(&wsm.idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1])) {
332 INIT_LIST_HEAD(&workspace->lru_list);
333 } else {
334 workspace->last_used = jiffies;
335 list_add(&workspace->lru_list, &wsm.lru_list);
336 if (!timer_pending(&wsm.timer))
337 mod_timer(&wsm.timer,
338 jiffies + ZSTD_BTRFS_RECLAIM_JIFFIES);
339 }
340 }
341
342 set_bit(workspace->level, &wsm.active_map);
343 list_add(&workspace->list, &wsm.idle_ws[workspace->level]);
344 workspace->req_level = 0;
345
346 spin_unlock_bh(&wsm.lock);
347
348 if (workspace->level == clip_level(ZSTD_BTRFS_MAX_LEVEL))
349 cond_wake_up(&wsm.wait);
350 }
351
zstd_free_workspace(struct list_head * ws)352 void zstd_free_workspace(struct list_head *ws)
353 {
354 struct workspace *workspace = list_entry(ws, struct workspace, list);
355
356 kvfree(workspace->mem);
357 kfree(workspace->buf);
358 kfree(workspace);
359 }
360
zstd_alloc_workspace(int level)361 struct list_head *zstd_alloc_workspace(int level)
362 {
363 struct workspace *workspace;
364
365 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
366 if (!workspace)
367 return ERR_PTR(-ENOMEM);
368
369 /* Use level 1 workspace size for all the fast mode negative levels. */
370 workspace->size = zstd_ws_mem_sizes[clip_level(level)];
371 workspace->level = clip_level(level);
372 workspace->req_level = level;
373 workspace->last_used = jiffies;
374 workspace->mem = kvmalloc(workspace->size, GFP_KERNEL | __GFP_NOWARN);
375 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
376 if (!workspace->mem || !workspace->buf)
377 goto fail;
378
379 INIT_LIST_HEAD(&workspace->list);
380 INIT_LIST_HEAD(&workspace->lru_list);
381
382 return &workspace->list;
383 fail:
384 zstd_free_workspace(&workspace->list);
385 return ERR_PTR(-ENOMEM);
386 }
387
zstd_compress_folios(struct list_head * ws,struct address_space * mapping,u64 start,struct folio ** folios,unsigned long * out_folios,unsigned long * total_in,unsigned long * total_out)388 int zstd_compress_folios(struct list_head *ws, struct address_space *mapping,
389 u64 start, struct folio **folios, unsigned long *out_folios,
390 unsigned long *total_in, unsigned long *total_out)
391 {
392 struct workspace *workspace = list_entry(ws, struct workspace, list);
393 zstd_cstream *stream;
394 int ret = 0;
395 int nr_folios = 0;
396 struct folio *in_folio = NULL; /* The current folio to read. */
397 struct folio *out_folio = NULL; /* The current folio to write to. */
398 unsigned long tot_in = 0;
399 unsigned long tot_out = 0;
400 unsigned long len = *total_out;
401 const unsigned long nr_dest_folios = *out_folios;
402 const u64 orig_end = start + len;
403 unsigned long max_out = nr_dest_folios * PAGE_SIZE;
404 unsigned int cur_len;
405
406 workspace->params = zstd_get_btrfs_parameters(workspace->req_level, len);
407 *out_folios = 0;
408 *total_out = 0;
409 *total_in = 0;
410
411 /* Initialize the stream */
412 stream = zstd_init_cstream(&workspace->params, len, workspace->mem,
413 workspace->size);
414 if (unlikely(!stream)) {
415 struct btrfs_inode *inode = BTRFS_I(mapping->host);
416
417 btrfs_err(inode->root->fs_info,
418 "zstd compression init level %d failed, root %llu inode %llu offset %llu",
419 workspace->req_level, btrfs_root_id(inode->root),
420 btrfs_ino(inode), start);
421 ret = -EIO;
422 goto out;
423 }
424
425 /* map in the first page of input data */
426 ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);
427 if (ret < 0)
428 goto out;
429 cur_len = btrfs_calc_input_length(orig_end, start);
430 workspace->in_buf.src = kmap_local_folio(in_folio, offset_in_page(start));
431 workspace->in_buf.pos = 0;
432 workspace->in_buf.size = cur_len;
433
434 /* Allocate and map in the output buffer */
435 out_folio = btrfs_alloc_compr_folio();
436 if (out_folio == NULL) {
437 ret = -ENOMEM;
438 goto out;
439 }
440 folios[nr_folios++] = out_folio;
441 workspace->out_buf.dst = folio_address(out_folio);
442 workspace->out_buf.pos = 0;
443 workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
444
445 while (1) {
446 size_t ret2;
447
448 ret2 = zstd_compress_stream(stream, &workspace->out_buf,
449 &workspace->in_buf);
450 if (unlikely(zstd_is_error(ret2))) {
451 struct btrfs_inode *inode = BTRFS_I(mapping->host);
452
453 btrfs_warn(inode->root->fs_info,
454 "zstd compression level %d failed, error %d root %llu inode %llu offset %llu",
455 workspace->req_level, zstd_get_error_code(ret2),
456 btrfs_root_id(inode->root), btrfs_ino(inode),
457 start);
458 ret = -EIO;
459 goto out;
460 }
461
462 /* Check to see if we are making it bigger */
463 if (tot_in + workspace->in_buf.pos > 8192 &&
464 tot_in + workspace->in_buf.pos <
465 tot_out + workspace->out_buf.pos) {
466 ret = -E2BIG;
467 goto out;
468 }
469
470 /* We've reached the end of our output range */
471 if (workspace->out_buf.pos >= max_out) {
472 tot_out += workspace->out_buf.pos;
473 ret = -E2BIG;
474 goto out;
475 }
476
477 /* Check if we need more output space */
478 if (workspace->out_buf.pos == workspace->out_buf.size) {
479 tot_out += PAGE_SIZE;
480 max_out -= PAGE_SIZE;
481 if (nr_folios == nr_dest_folios) {
482 ret = -E2BIG;
483 goto out;
484 }
485 out_folio = btrfs_alloc_compr_folio();
486 if (out_folio == NULL) {
487 ret = -ENOMEM;
488 goto out;
489 }
490 folios[nr_folios++] = out_folio;
491 workspace->out_buf.dst = folio_address(out_folio);
492 workspace->out_buf.pos = 0;
493 workspace->out_buf.size = min_t(size_t, max_out,
494 PAGE_SIZE);
495 }
496
497 /* We've reached the end of the input */
498 if (workspace->in_buf.pos >= len) {
499 tot_in += workspace->in_buf.pos;
500 break;
501 }
502
503 /* Check if we need more input */
504 if (workspace->in_buf.pos == workspace->in_buf.size) {
505 tot_in += workspace->in_buf.size;
506 kunmap_local(workspace->in_buf.src);
507 workspace->in_buf.src = NULL;
508 folio_put(in_folio);
509 start += cur_len;
510 len -= cur_len;
511 ret = btrfs_compress_filemap_get_folio(mapping, start, &in_folio);
512 if (ret < 0)
513 goto out;
514 cur_len = btrfs_calc_input_length(orig_end, start);
515 workspace->in_buf.src = kmap_local_folio(in_folio,
516 offset_in_page(start));
517 workspace->in_buf.pos = 0;
518 workspace->in_buf.size = cur_len;
519 }
520 }
521 while (1) {
522 size_t ret2;
523
524 ret2 = zstd_end_stream(stream, &workspace->out_buf);
525 if (unlikely(zstd_is_error(ret2))) {
526 struct btrfs_inode *inode = BTRFS_I(mapping->host);
527
528 btrfs_err(inode->root->fs_info,
529 "zstd compression end level %d failed, error %d root %llu inode %llu offset %llu",
530 workspace->req_level, zstd_get_error_code(ret2),
531 btrfs_root_id(inode->root), btrfs_ino(inode),
532 start);
533 ret = -EIO;
534 goto out;
535 }
536 if (ret2 == 0) {
537 tot_out += workspace->out_buf.pos;
538 break;
539 }
540 if (workspace->out_buf.pos >= max_out) {
541 tot_out += workspace->out_buf.pos;
542 ret = -E2BIG;
543 goto out;
544 }
545
546 tot_out += PAGE_SIZE;
547 max_out -= PAGE_SIZE;
548 if (nr_folios == nr_dest_folios) {
549 ret = -E2BIG;
550 goto out;
551 }
552 out_folio = btrfs_alloc_compr_folio();
553 if (out_folio == NULL) {
554 ret = -ENOMEM;
555 goto out;
556 }
557 folios[nr_folios++] = out_folio;
558 workspace->out_buf.dst = folio_address(out_folio);
559 workspace->out_buf.pos = 0;
560 workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
561 }
562
563 if (tot_out >= tot_in) {
564 ret = -E2BIG;
565 goto out;
566 }
567
568 ret = 0;
569 *total_in = tot_in;
570 *total_out = tot_out;
571 out:
572 *out_folios = nr_folios;
573 if (workspace->in_buf.src) {
574 kunmap_local(workspace->in_buf.src);
575 folio_put(in_folio);
576 }
577 return ret;
578 }
579
zstd_decompress_bio(struct list_head * ws,struct compressed_bio * cb)580 int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
581 {
582 struct workspace *workspace = list_entry(ws, struct workspace, list);
583 struct folio **folios_in = cb->compressed_folios;
584 size_t srclen = cb->compressed_len;
585 zstd_dstream *stream;
586 int ret = 0;
587 unsigned long folio_in_index = 0;
588 unsigned long total_folios_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
589 unsigned long buf_start;
590 unsigned long total_out = 0;
591
592 stream = zstd_init_dstream(
593 ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
594 if (unlikely(!stream)) {
595 struct btrfs_inode *inode = cb->bbio.inode;
596
597 btrfs_err(inode->root->fs_info,
598 "zstd decompression init failed, root %llu inode %llu offset %llu",
599 btrfs_root_id(inode->root), btrfs_ino(inode), cb->start);
600 ret = -EIO;
601 goto done;
602 }
603
604 workspace->in_buf.src = kmap_local_folio(folios_in[folio_in_index], 0);
605 workspace->in_buf.pos = 0;
606 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
607
608 workspace->out_buf.dst = workspace->buf;
609 workspace->out_buf.pos = 0;
610 workspace->out_buf.size = PAGE_SIZE;
611
612 while (1) {
613 size_t ret2;
614
615 ret2 = zstd_decompress_stream(stream, &workspace->out_buf,
616 &workspace->in_buf);
617 if (unlikely(zstd_is_error(ret2))) {
618 struct btrfs_inode *inode = cb->bbio.inode;
619
620 btrfs_err(inode->root->fs_info,
621 "zstd decompression failed, error %d root %llu inode %llu offset %llu",
622 zstd_get_error_code(ret2), btrfs_root_id(inode->root),
623 btrfs_ino(inode), cb->start);
624 ret = -EIO;
625 goto done;
626 }
627 buf_start = total_out;
628 total_out += workspace->out_buf.pos;
629 workspace->out_buf.pos = 0;
630
631 ret = btrfs_decompress_buf2page(workspace->out_buf.dst,
632 total_out - buf_start, cb, buf_start);
633 if (ret == 0)
634 break;
635
636 if (workspace->in_buf.pos >= srclen)
637 break;
638
639 /* Check if we've hit the end of a frame */
640 if (ret2 == 0)
641 break;
642
643 if (workspace->in_buf.pos == workspace->in_buf.size) {
644 kunmap_local(workspace->in_buf.src);
645 folio_in_index++;
646 if (folio_in_index >= total_folios_in) {
647 workspace->in_buf.src = NULL;
648 ret = -EIO;
649 goto done;
650 }
651 srclen -= PAGE_SIZE;
652 workspace->in_buf.src =
653 kmap_local_folio(folios_in[folio_in_index], 0);
654 workspace->in_buf.pos = 0;
655 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
656 }
657 }
658 ret = 0;
659 done:
660 if (workspace->in_buf.src)
661 kunmap_local(workspace->in_buf.src);
662 return ret;
663 }
664
zstd_decompress(struct list_head * ws,const u8 * data_in,struct folio * dest_folio,unsigned long dest_pgoff,size_t srclen,size_t destlen)665 int zstd_decompress(struct list_head *ws, const u8 *data_in,
666 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
667 size_t destlen)
668 {
669 struct workspace *workspace = list_entry(ws, struct workspace, list);
670 struct btrfs_fs_info *fs_info = btrfs_sb(folio_inode(dest_folio)->i_sb);
671 const u32 sectorsize = fs_info->sectorsize;
672 zstd_dstream *stream;
673 int ret = 0;
674 unsigned long to_copy = 0;
675
676 stream = zstd_init_dstream(
677 ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
678 if (unlikely(!stream)) {
679 struct btrfs_inode *inode = folio_to_inode(dest_folio);
680
681 btrfs_err(inode->root->fs_info,
682 "zstd decompression init failed, root %llu inode %llu offset %llu",
683 btrfs_root_id(inode->root), btrfs_ino(inode),
684 folio_pos(dest_folio));
685 ret = -EIO;
686 goto finish;
687 }
688
689 workspace->in_buf.src = data_in;
690 workspace->in_buf.pos = 0;
691 workspace->in_buf.size = srclen;
692
693 workspace->out_buf.dst = workspace->buf;
694 workspace->out_buf.pos = 0;
695 workspace->out_buf.size = sectorsize;
696
697 /*
698 * Since both input and output buffers should not exceed one sector,
699 * one call should end the decompression.
700 */
701 ret = zstd_decompress_stream(stream, &workspace->out_buf, &workspace->in_buf);
702 if (unlikely(zstd_is_error(ret))) {
703 struct btrfs_inode *inode = folio_to_inode(dest_folio);
704
705 btrfs_err(inode->root->fs_info,
706 "zstd decompression failed, error %d root %llu inode %llu offset %llu",
707 zstd_get_error_code(ret), btrfs_root_id(inode->root),
708 btrfs_ino(inode), folio_pos(dest_folio));
709 goto finish;
710 }
711 to_copy = workspace->out_buf.pos;
712 memcpy_to_folio(dest_folio, dest_pgoff, workspace->out_buf.dst, to_copy);
713 finish:
714 /* Error or early end. */
715 if (unlikely(to_copy < destlen)) {
716 ret = -EIO;
717 folio_zero_range(dest_folio, dest_pgoff + to_copy, destlen - to_copy);
718 }
719 return ret;
720 }
721
722 const struct btrfs_compress_op btrfs_zstd_compress = {
723 /* ZSTD uses own workspace manager */
724 .workspace_manager = NULL,
725 .min_level = ZSTD_BTRFS_MIN_LEVEL,
726 .max_level = ZSTD_BTRFS_MAX_LEVEL,
727 .default_level = ZSTD_BTRFS_DEFAULT_LEVEL,
728 };
729