Commit | Line | Data |
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c1d7c514 | 1 | // SPDX-License-Identifier: GPL-2.0 |
7414a03f AJ |
2 | /* |
3 | * Copyright (C) 2011 STRATO. All rights reserved. | |
7414a03f AJ |
4 | */ |
5 | ||
6 | #include <linux/sched.h> | |
7 | #include <linux/pagemap.h> | |
8 | #include <linux/writeback.h> | |
9 | #include <linux/blkdev.h> | |
10 | #include <linux/rbtree.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/workqueue.h> | |
13 | #include "ctree.h" | |
14 | #include "volumes.h" | |
15 | #include "disk-io.h" | |
16 | #include "transaction.h" | |
8dabb742 | 17 | #include "dev-replace.h" |
7414a03f AJ |
18 | |
19 | #undef DEBUG | |
20 | ||
21 | /* | |
22 | * This is the implementation for the generic read ahead framework. | |
23 | * | |
24 | * To trigger a readahead, btrfs_reada_add must be called. It will start | |
25 | * a read ahead for the given range [start, end) on tree root. The returned | |
26 | * handle can either be used to wait on the readahead to finish | |
27 | * (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach). | |
28 | * | |
29 | * The read ahead works as follows: | |
30 | * On btrfs_reada_add, the root of the tree is inserted into a radix_tree. | |
31 | * reada_start_machine will then search for extents to prefetch and trigger | |
32 | * some reads. When a read finishes for a node, all contained node/leaf | |
33 | * pointers that lie in the given range will also be enqueued. The reads will | |
34 | * be triggered in sequential order, thus giving a big win over a naive | |
35 | * enumeration. It will also make use of multi-device layouts. Each disk | |
36 | * will have its on read pointer and all disks will by utilized in parallel. | |
37 | * Also will no two disks read both sides of a mirror simultaneously, as this | |
38 | * would waste seeking capacity. Instead both disks will read different parts | |
39 | * of the filesystem. | |
40 | * Any number of readaheads can be started in parallel. The read order will be | |
41 | * determined globally, i.e. 2 parallel readaheads will normally finish faster | |
42 | * than the 2 started one after another. | |
43 | */ | |
44 | ||
7414a03f AJ |
45 | #define MAX_IN_FLIGHT 6 |
46 | ||
47 | struct reada_extctl { | |
48 | struct list_head list; | |
49 | struct reada_control *rc; | |
50 | u64 generation; | |
51 | }; | |
52 | ||
53 | struct reada_extent { | |
54 | u64 logical; | |
55 | struct btrfs_key top; | |
7414a03f | 56 | struct list_head extctl; |
99621b44 | 57 | int refcnt; |
7414a03f | 58 | spinlock_t lock; |
94598ba8 | 59 | struct reada_zone *zones[BTRFS_MAX_MIRRORS]; |
7414a03f | 60 | int nzones; |
895a11b8 | 61 | int scheduled; |
7414a03f AJ |
62 | }; |
63 | ||
64 | struct reada_zone { | |
65 | u64 start; | |
66 | u64 end; | |
67 | u64 elems; | |
68 | struct list_head list; | |
69 | spinlock_t lock; | |
70 | int locked; | |
71 | struct btrfs_device *device; | |
94598ba8 SB |
72 | struct btrfs_device *devs[BTRFS_MAX_MIRRORS]; /* full list, incl |
73 | * self */ | |
7414a03f AJ |
74 | int ndevs; |
75 | struct kref refcnt; | |
76 | }; | |
77 | ||
78 | struct reada_machine_work { | |
d458b054 | 79 | struct btrfs_work work; |
7414a03f AJ |
80 | struct btrfs_fs_info *fs_info; |
81 | }; | |
82 | ||
83 | static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *); | |
84 | static void reada_control_release(struct kref *kref); | |
85 | static void reada_zone_release(struct kref *kref); | |
86 | static void reada_start_machine(struct btrfs_fs_info *fs_info); | |
87 | static void __reada_start_machine(struct btrfs_fs_info *fs_info); | |
88 | ||
89 | static int reada_add_block(struct reada_control *rc, u64 logical, | |
1e7970c0 | 90 | struct btrfs_key *top, u64 generation); |
7414a03f AJ |
91 | |
92 | /* recurses */ | |
93 | /* in case of err, eb might be NULL */ | |
02873e43 ZL |
94 | static void __readahead_hook(struct btrfs_fs_info *fs_info, |
95 | struct reada_extent *re, struct extent_buffer *eb, | |
bcdc51b2 | 96 | int err) |
7414a03f | 97 | { |
7414a03f AJ |
98 | int nritems; |
99 | int i; | |
100 | u64 bytenr; | |
101 | u64 generation; | |
7414a03f | 102 | struct list_head list; |
7414a03f | 103 | |
7414a03f AJ |
104 | spin_lock(&re->lock); |
105 | /* | |
106 | * just take the full list from the extent. afterwards we | |
107 | * don't need the lock anymore | |
108 | */ | |
109 | list_replace_init(&re->extctl, &list); | |
895a11b8 | 110 | re->scheduled = 0; |
7414a03f AJ |
111 | spin_unlock(&re->lock); |
112 | ||
57f16e08 ZL |
113 | /* |
114 | * this is the error case, the extent buffer has not been | |
115 | * read correctly. We won't access anything from it and | |
116 | * just cleanup our data structures. Effectively this will | |
117 | * cut the branch below this node from read ahead. | |
118 | */ | |
119 | if (err) | |
120 | goto cleanup; | |
7414a03f | 121 | |
57f16e08 ZL |
122 | /* |
123 | * FIXME: currently we just set nritems to 0 if this is a leaf, | |
124 | * effectively ignoring the content. In a next step we could | |
125 | * trigger more readahead depending from the content, e.g. | |
126 | * fetch the checksums for the extents in the leaf. | |
127 | */ | |
04998b33 | 128 | if (!btrfs_header_level(eb)) |
57f16e08 ZL |
129 | goto cleanup; |
130 | ||
131 | nritems = btrfs_header_nritems(eb); | |
132 | generation = btrfs_header_generation(eb); | |
7414a03f AJ |
133 | for (i = 0; i < nritems; i++) { |
134 | struct reada_extctl *rec; | |
135 | u64 n_gen; | |
136 | struct btrfs_key key; | |
137 | struct btrfs_key next_key; | |
138 | ||
139 | btrfs_node_key_to_cpu(eb, &key, i); | |
140 | if (i + 1 < nritems) | |
141 | btrfs_node_key_to_cpu(eb, &next_key, i + 1); | |
142 | else | |
143 | next_key = re->top; | |
144 | bytenr = btrfs_node_blockptr(eb, i); | |
145 | n_gen = btrfs_node_ptr_generation(eb, i); | |
146 | ||
147 | list_for_each_entry(rec, &list, list) { | |
148 | struct reada_control *rc = rec->rc; | |
149 | ||
150 | /* | |
151 | * if the generation doesn't match, just ignore this | |
152 | * extctl. This will probably cut off a branch from | |
153 | * prefetch. Alternatively one could start a new (sub-) | |
154 | * prefetch for this branch, starting again from root. | |
155 | * FIXME: move the generation check out of this loop | |
156 | */ | |
157 | #ifdef DEBUG | |
158 | if (rec->generation != generation) { | |
02873e43 ZL |
159 | btrfs_debug(fs_info, |
160 | "generation mismatch for (%llu,%d,%llu) %llu != %llu", | |
161 | key.objectid, key.type, key.offset, | |
162 | rec->generation, generation); | |
7414a03f AJ |
163 | } |
164 | #endif | |
165 | if (rec->generation == generation && | |
166 | btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 && | |
167 | btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0) | |
1e7970c0 | 168 | reada_add_block(rc, bytenr, &next_key, n_gen); |
7414a03f AJ |
169 | } |
170 | } | |
57f16e08 ZL |
171 | |
172 | cleanup: | |
7414a03f AJ |
173 | /* |
174 | * free extctl records | |
175 | */ | |
176 | while (!list_empty(&list)) { | |
177 | struct reada_control *rc; | |
178 | struct reada_extctl *rec; | |
179 | ||
180 | rec = list_first_entry(&list, struct reada_extctl, list); | |
181 | list_del(&rec->list); | |
182 | rc = rec->rc; | |
183 | kfree(rec); | |
184 | ||
185 | kref_get(&rc->refcnt); | |
186 | if (atomic_dec_and_test(&rc->elems)) { | |
187 | kref_put(&rc->refcnt, reada_control_release); | |
188 | wake_up(&rc->wait); | |
189 | } | |
190 | kref_put(&rc->refcnt, reada_control_release); | |
191 | ||
192 | reada_extent_put(fs_info, re); /* one ref for each entry */ | |
193 | } | |
7414a03f | 194 | |
6e39dbe8 | 195 | return; |
7414a03f AJ |
196 | } |
197 | ||
d48d71aa | 198 | int btree_readahead_hook(struct extent_buffer *eb, int err) |
7414a03f | 199 | { |
d48d71aa | 200 | struct btrfs_fs_info *fs_info = eb->fs_info; |
6e39dbe8 ZL |
201 | int ret = 0; |
202 | struct reada_extent *re; | |
7414a03f | 203 | |
6e39dbe8 ZL |
204 | /* find extent */ |
205 | spin_lock(&fs_info->reada_lock); | |
206 | re = radix_tree_lookup(&fs_info->reada_tree, | |
fc2e901f | 207 | eb->start >> PAGE_SHIFT); |
6e39dbe8 ZL |
208 | if (re) |
209 | re->refcnt++; | |
210 | spin_unlock(&fs_info->reada_lock); | |
211 | if (!re) { | |
212 | ret = -1; | |
213 | goto start_machine; | |
214 | } | |
7414a03f | 215 | |
bcdc51b2 | 216 | __readahead_hook(fs_info, re, eb, err); |
6e39dbe8 | 217 | reada_extent_put(fs_info, re); /* our ref */ |
7414a03f | 218 | |
6e39dbe8 ZL |
219 | start_machine: |
220 | reada_start_machine(fs_info); | |
7414a03f AJ |
221 | return ret; |
222 | } | |
223 | ||
0ceaf282 | 224 | static struct reada_zone *reada_find_zone(struct btrfs_device *dev, u64 logical, |
21ca543e | 225 | struct btrfs_bio *bbio) |
7414a03f | 226 | { |
0ceaf282 | 227 | struct btrfs_fs_info *fs_info = dev->fs_info; |
7414a03f | 228 | int ret; |
7414a03f AJ |
229 | struct reada_zone *zone; |
230 | struct btrfs_block_group_cache *cache = NULL; | |
231 | u64 start; | |
232 | u64 end; | |
233 | int i; | |
234 | ||
7414a03f AJ |
235 | zone = NULL; |
236 | spin_lock(&fs_info->reada_lock); | |
237 | ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone, | |
09cbfeaf | 238 | logical >> PAGE_SHIFT, 1); |
c37f49c7 | 239 | if (ret == 1 && logical >= zone->start && logical <= zone->end) { |
7414a03f | 240 | kref_get(&zone->refcnt); |
7414a03f | 241 | spin_unlock(&fs_info->reada_lock); |
c37f49c7 | 242 | return zone; |
7414a03f AJ |
243 | } |
244 | ||
c37f49c7 ZL |
245 | spin_unlock(&fs_info->reada_lock); |
246 | ||
7414a03f AJ |
247 | cache = btrfs_lookup_block_group(fs_info, logical); |
248 | if (!cache) | |
249 | return NULL; | |
250 | ||
251 | start = cache->key.objectid; | |
252 | end = start + cache->key.offset - 1; | |
253 | btrfs_put_block_group(cache); | |
254 | ||
ed0244fa | 255 | zone = kzalloc(sizeof(*zone), GFP_KERNEL); |
7414a03f AJ |
256 | if (!zone) |
257 | return NULL; | |
258 | ||
cc8385b5 DS |
259 | ret = radix_tree_preload(GFP_KERNEL); |
260 | if (ret) { | |
261 | kfree(zone); | |
262 | return NULL; | |
263 | } | |
264 | ||
7414a03f AJ |
265 | zone->start = start; |
266 | zone->end = end; | |
267 | INIT_LIST_HEAD(&zone->list); | |
268 | spin_lock_init(&zone->lock); | |
269 | zone->locked = 0; | |
270 | kref_init(&zone->refcnt); | |
271 | zone->elems = 0; | |
272 | zone->device = dev; /* our device always sits at index 0 */ | |
21ca543e | 273 | for (i = 0; i < bbio->num_stripes; ++i) { |
7414a03f | 274 | /* bounds have already been checked */ |
21ca543e | 275 | zone->devs[i] = bbio->stripes[i].dev; |
7414a03f | 276 | } |
21ca543e | 277 | zone->ndevs = bbio->num_stripes; |
7414a03f AJ |
278 | |
279 | spin_lock(&fs_info->reada_lock); | |
280 | ret = radix_tree_insert(&dev->reada_zones, | |
09cbfeaf | 281 | (unsigned long)(zone->end >> PAGE_SHIFT), |
7414a03f | 282 | zone); |
7414a03f | 283 | |
8c9c2bf7 | 284 | if (ret == -EEXIST) { |
7414a03f | 285 | kfree(zone); |
8c9c2bf7 | 286 | ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone, |
09cbfeaf | 287 | logical >> PAGE_SHIFT, 1); |
8e9aa51f | 288 | if (ret == 1 && logical >= zone->start && logical <= zone->end) |
8c9c2bf7 | 289 | kref_get(&zone->refcnt); |
8e9aa51f ZL |
290 | else |
291 | zone = NULL; | |
7414a03f | 292 | } |
8c9c2bf7 | 293 | spin_unlock(&fs_info->reada_lock); |
cc8385b5 | 294 | radix_tree_preload_end(); |
7414a03f AJ |
295 | |
296 | return zone; | |
297 | } | |
298 | ||
2ff7e61e | 299 | static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info, |
7414a03f | 300 | u64 logical, |
1e7970c0 | 301 | struct btrfs_key *top) |
7414a03f AJ |
302 | { |
303 | int ret; | |
7414a03f | 304 | struct reada_extent *re = NULL; |
8c9c2bf7 | 305 | struct reada_extent *re_exist = NULL; |
21ca543e | 306 | struct btrfs_bio *bbio = NULL; |
7414a03f | 307 | struct btrfs_device *dev; |
207a232c | 308 | struct btrfs_device *prev_dev; |
7414a03f | 309 | u64 length; |
7cb2c420 | 310 | int real_stripes; |
7414a03f | 311 | int nzones = 0; |
09cbfeaf | 312 | unsigned long index = logical >> PAGE_SHIFT; |
8dabb742 | 313 | int dev_replace_is_ongoing; |
31945021 | 314 | int have_zone = 0; |
7414a03f | 315 | |
7414a03f AJ |
316 | spin_lock(&fs_info->reada_lock); |
317 | re = radix_tree_lookup(&fs_info->reada_tree, index); | |
318 | if (re) | |
99621b44 | 319 | re->refcnt++; |
7414a03f AJ |
320 | spin_unlock(&fs_info->reada_lock); |
321 | ||
8c9c2bf7 | 322 | if (re) |
7414a03f AJ |
323 | return re; |
324 | ||
ed0244fa | 325 | re = kzalloc(sizeof(*re), GFP_KERNEL); |
7414a03f AJ |
326 | if (!re) |
327 | return NULL; | |
328 | ||
7414a03f | 329 | re->logical = logical; |
7414a03f AJ |
330 | re->top = *top; |
331 | INIT_LIST_HEAD(&re->extctl); | |
332 | spin_lock_init(&re->lock); | |
99621b44 | 333 | re->refcnt = 1; |
7414a03f AJ |
334 | |
335 | /* | |
336 | * map block | |
337 | */ | |
994a5d2b | 338 | length = fs_info->nodesize; |
cf8cddd3 CH |
339 | ret = btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical, |
340 | &length, &bbio, 0); | |
994a5d2b | 341 | if (ret || !bbio || length < fs_info->nodesize) |
7414a03f AJ |
342 | goto error; |
343 | ||
94598ba8 | 344 | if (bbio->num_stripes > BTRFS_MAX_MIRRORS) { |
0b246afa | 345 | btrfs_err(fs_info, |
efe120a0 FH |
346 | "readahead: more than %d copies not supported", |
347 | BTRFS_MAX_MIRRORS); | |
7414a03f AJ |
348 | goto error; |
349 | } | |
350 | ||
7cb2c420 OS |
351 | real_stripes = bbio->num_stripes - bbio->num_tgtdevs; |
352 | for (nzones = 0; nzones < real_stripes; ++nzones) { | |
7414a03f AJ |
353 | struct reada_zone *zone; |
354 | ||
21ca543e | 355 | dev = bbio->stripes[nzones].dev; |
7aff8cf4 ZL |
356 | |
357 | /* cannot read ahead on missing device. */ | |
358 | if (!dev->bdev) | |
359 | continue; | |
360 | ||
0ceaf282 | 361 | zone = reada_find_zone(dev, logical, bbio); |
7414a03f | 362 | if (!zone) |
6a159d2a | 363 | continue; |
7414a03f | 364 | |
6a159d2a | 365 | re->zones[re->nzones++] = zone; |
7414a03f AJ |
366 | spin_lock(&zone->lock); |
367 | if (!zone->elems) | |
368 | kref_get(&zone->refcnt); | |
369 | ++zone->elems; | |
370 | spin_unlock(&zone->lock); | |
371 | spin_lock(&fs_info->reada_lock); | |
372 | kref_put(&zone->refcnt, reada_zone_release); | |
373 | spin_unlock(&fs_info->reada_lock); | |
374 | } | |
6a159d2a | 375 | if (re->nzones == 0) { |
7414a03f AJ |
376 | /* not a single zone found, error and out */ |
377 | goto error; | |
378 | } | |
379 | ||
7ef70b4d DS |
380 | ret = radix_tree_preload(GFP_KERNEL); |
381 | if (ret) | |
382 | goto error; | |
383 | ||
7414a03f | 384 | /* insert extent in reada_tree + all per-device trees, all or nothing */ |
7e79cb86 | 385 | btrfs_dev_replace_read_lock(&fs_info->dev_replace); |
7414a03f AJ |
386 | spin_lock(&fs_info->reada_lock); |
387 | ret = radix_tree_insert(&fs_info->reada_tree, index, re); | |
8c9c2bf7 AJ |
388 | if (ret == -EEXIST) { |
389 | re_exist = radix_tree_lookup(&fs_info->reada_tree, index); | |
99621b44 | 390 | re_exist->refcnt++; |
8c9c2bf7 | 391 | spin_unlock(&fs_info->reada_lock); |
7e79cb86 | 392 | btrfs_dev_replace_read_unlock(&fs_info->dev_replace); |
7ef70b4d | 393 | radix_tree_preload_end(); |
8c9c2bf7 AJ |
394 | goto error; |
395 | } | |
7414a03f AJ |
396 | if (ret) { |
397 | spin_unlock(&fs_info->reada_lock); | |
7e79cb86 | 398 | btrfs_dev_replace_read_unlock(&fs_info->dev_replace); |
7ef70b4d | 399 | radix_tree_preload_end(); |
7414a03f AJ |
400 | goto error; |
401 | } | |
7ef70b4d | 402 | radix_tree_preload_end(); |
207a232c | 403 | prev_dev = NULL; |
8dabb742 SB |
404 | dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing( |
405 | &fs_info->dev_replace); | |
6a159d2a ZL |
406 | for (nzones = 0; nzones < re->nzones; ++nzones) { |
407 | dev = re->zones[nzones]->device; | |
408 | ||
207a232c AJ |
409 | if (dev == prev_dev) { |
410 | /* | |
411 | * in case of DUP, just add the first zone. As both | |
412 | * are on the same device, there's nothing to gain | |
413 | * from adding both. | |
414 | * Also, it wouldn't work, as the tree is per device | |
415 | * and adding would fail with EEXIST | |
416 | */ | |
417 | continue; | |
418 | } | |
7aff8cf4 ZL |
419 | if (!dev->bdev) |
420 | continue; | |
421 | ||
8dabb742 SB |
422 | if (dev_replace_is_ongoing && |
423 | dev == fs_info->dev_replace.tgtdev) { | |
424 | /* | |
425 | * as this device is selected for reading only as | |
426 | * a last resort, skip it for read ahead. | |
427 | */ | |
428 | continue; | |
429 | } | |
207a232c | 430 | prev_dev = dev; |
7414a03f AJ |
431 | ret = radix_tree_insert(&dev->reada_extents, index, re); |
432 | if (ret) { | |
6a159d2a ZL |
433 | while (--nzones >= 0) { |
434 | dev = re->zones[nzones]->device; | |
7414a03f | 435 | BUG_ON(dev == NULL); |
ff023aac | 436 | /* ignore whether the entry was inserted */ |
7414a03f AJ |
437 | radix_tree_delete(&dev->reada_extents, index); |
438 | } | |
7414a03f AJ |
439 | radix_tree_delete(&fs_info->reada_tree, index); |
440 | spin_unlock(&fs_info->reada_lock); | |
7e79cb86 | 441 | btrfs_dev_replace_read_unlock(&fs_info->dev_replace); |
7414a03f AJ |
442 | goto error; |
443 | } | |
31945021 | 444 | have_zone = 1; |
7414a03f AJ |
445 | } |
446 | spin_unlock(&fs_info->reada_lock); | |
7e79cb86 | 447 | btrfs_dev_replace_read_unlock(&fs_info->dev_replace); |
7414a03f | 448 | |
31945021 ZL |
449 | if (!have_zone) |
450 | goto error; | |
451 | ||
6e9606d2 | 452 | btrfs_put_bbio(bbio); |
7414a03f AJ |
453 | return re; |
454 | ||
455 | error: | |
6a159d2a | 456 | for (nzones = 0; nzones < re->nzones; ++nzones) { |
7414a03f AJ |
457 | struct reada_zone *zone; |
458 | ||
7414a03f AJ |
459 | zone = re->zones[nzones]; |
460 | kref_get(&zone->refcnt); | |
461 | spin_lock(&zone->lock); | |
462 | --zone->elems; | |
463 | if (zone->elems == 0) { | |
464 | /* | |
465 | * no fs_info->reada_lock needed, as this can't be | |
466 | * the last ref | |
467 | */ | |
468 | kref_put(&zone->refcnt, reada_zone_release); | |
469 | } | |
470 | spin_unlock(&zone->lock); | |
471 | ||
472 | spin_lock(&fs_info->reada_lock); | |
473 | kref_put(&zone->refcnt, reada_zone_release); | |
474 | spin_unlock(&fs_info->reada_lock); | |
475 | } | |
6e9606d2 | 476 | btrfs_put_bbio(bbio); |
7414a03f | 477 | kfree(re); |
8c9c2bf7 | 478 | return re_exist; |
7414a03f AJ |
479 | } |
480 | ||
7414a03f AJ |
481 | static void reada_extent_put(struct btrfs_fs_info *fs_info, |
482 | struct reada_extent *re) | |
483 | { | |
484 | int i; | |
09cbfeaf | 485 | unsigned long index = re->logical >> PAGE_SHIFT; |
7414a03f AJ |
486 | |
487 | spin_lock(&fs_info->reada_lock); | |
99621b44 | 488 | if (--re->refcnt) { |
7414a03f AJ |
489 | spin_unlock(&fs_info->reada_lock); |
490 | return; | |
491 | } | |
492 | ||
493 | radix_tree_delete(&fs_info->reada_tree, index); | |
494 | for (i = 0; i < re->nzones; ++i) { | |
495 | struct reada_zone *zone = re->zones[i]; | |
496 | ||
497 | radix_tree_delete(&zone->device->reada_extents, index); | |
498 | } | |
499 | ||
500 | spin_unlock(&fs_info->reada_lock); | |
501 | ||
502 | for (i = 0; i < re->nzones; ++i) { | |
503 | struct reada_zone *zone = re->zones[i]; | |
504 | ||
505 | kref_get(&zone->refcnt); | |
506 | spin_lock(&zone->lock); | |
507 | --zone->elems; | |
508 | if (zone->elems == 0) { | |
509 | /* no fs_info->reada_lock needed, as this can't be | |
510 | * the last ref */ | |
511 | kref_put(&zone->refcnt, reada_zone_release); | |
512 | } | |
513 | spin_unlock(&zone->lock); | |
514 | ||
515 | spin_lock(&fs_info->reada_lock); | |
516 | kref_put(&zone->refcnt, reada_zone_release); | |
517 | spin_unlock(&fs_info->reada_lock); | |
518 | } | |
7414a03f AJ |
519 | |
520 | kfree(re); | |
521 | } | |
522 | ||
523 | static void reada_zone_release(struct kref *kref) | |
524 | { | |
525 | struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt); | |
526 | ||
527 | radix_tree_delete(&zone->device->reada_zones, | |
09cbfeaf | 528 | zone->end >> PAGE_SHIFT); |
7414a03f AJ |
529 | |
530 | kfree(zone); | |
531 | } | |
532 | ||
533 | static void reada_control_release(struct kref *kref) | |
534 | { | |
535 | struct reada_control *rc = container_of(kref, struct reada_control, | |
536 | refcnt); | |
537 | ||
538 | kfree(rc); | |
539 | } | |
540 | ||
541 | static int reada_add_block(struct reada_control *rc, u64 logical, | |
1e7970c0 | 542 | struct btrfs_key *top, u64 generation) |
7414a03f | 543 | { |
c28f158e | 544 | struct btrfs_fs_info *fs_info = rc->fs_info; |
7414a03f AJ |
545 | struct reada_extent *re; |
546 | struct reada_extctl *rec; | |
547 | ||
c28f158e | 548 | /* takes one ref */ |
2ff7e61e | 549 | re = reada_find_extent(fs_info, logical, top); |
7414a03f AJ |
550 | if (!re) |
551 | return -1; | |
552 | ||
ed0244fa | 553 | rec = kzalloc(sizeof(*rec), GFP_KERNEL); |
7414a03f | 554 | if (!rec) { |
c28f158e | 555 | reada_extent_put(fs_info, re); |
ddd664f4 | 556 | return -ENOMEM; |
7414a03f AJ |
557 | } |
558 | ||
559 | rec->rc = rc; | |
560 | rec->generation = generation; | |
561 | atomic_inc(&rc->elems); | |
562 | ||
563 | spin_lock(&re->lock); | |
564 | list_add_tail(&rec->list, &re->extctl); | |
565 | spin_unlock(&re->lock); | |
566 | ||
567 | /* leave the ref on the extent */ | |
568 | ||
569 | return 0; | |
570 | } | |
571 | ||
572 | /* | |
573 | * called with fs_info->reada_lock held | |
574 | */ | |
575 | static void reada_peer_zones_set_lock(struct reada_zone *zone, int lock) | |
576 | { | |
577 | int i; | |
09cbfeaf | 578 | unsigned long index = zone->end >> PAGE_SHIFT; |
7414a03f AJ |
579 | |
580 | for (i = 0; i < zone->ndevs; ++i) { | |
581 | struct reada_zone *peer; | |
582 | peer = radix_tree_lookup(&zone->devs[i]->reada_zones, index); | |
583 | if (peer && peer->device != zone->device) | |
584 | peer->locked = lock; | |
585 | } | |
586 | } | |
587 | ||
588 | /* | |
589 | * called with fs_info->reada_lock held | |
590 | */ | |
591 | static int reada_pick_zone(struct btrfs_device *dev) | |
592 | { | |
593 | struct reada_zone *top_zone = NULL; | |
594 | struct reada_zone *top_locked_zone = NULL; | |
595 | u64 top_elems = 0; | |
596 | u64 top_locked_elems = 0; | |
597 | unsigned long index = 0; | |
598 | int ret; | |
599 | ||
600 | if (dev->reada_curr_zone) { | |
601 | reada_peer_zones_set_lock(dev->reada_curr_zone, 0); | |
602 | kref_put(&dev->reada_curr_zone->refcnt, reada_zone_release); | |
603 | dev->reada_curr_zone = NULL; | |
604 | } | |
605 | /* pick the zone with the most elements */ | |
606 | while (1) { | |
607 | struct reada_zone *zone; | |
608 | ||
609 | ret = radix_tree_gang_lookup(&dev->reada_zones, | |
610 | (void **)&zone, index, 1); | |
611 | if (ret == 0) | |
612 | break; | |
09cbfeaf | 613 | index = (zone->end >> PAGE_SHIFT) + 1; |
7414a03f AJ |
614 | if (zone->locked) { |
615 | if (zone->elems > top_locked_elems) { | |
616 | top_locked_elems = zone->elems; | |
617 | top_locked_zone = zone; | |
618 | } | |
619 | } else { | |
620 | if (zone->elems > top_elems) { | |
621 | top_elems = zone->elems; | |
622 | top_zone = zone; | |
623 | } | |
624 | } | |
625 | } | |
626 | if (top_zone) | |
627 | dev->reada_curr_zone = top_zone; | |
628 | else if (top_locked_zone) | |
629 | dev->reada_curr_zone = top_locked_zone; | |
630 | else | |
631 | return 0; | |
632 | ||
633 | dev->reada_next = dev->reada_curr_zone->start; | |
634 | kref_get(&dev->reada_curr_zone->refcnt); | |
635 | reada_peer_zones_set_lock(dev->reada_curr_zone, 1); | |
636 | ||
637 | return 1; | |
638 | } | |
639 | ||
5721b8ad | 640 | static int reada_start_machine_dev(struct btrfs_device *dev) |
7414a03f | 641 | { |
5721b8ad | 642 | struct btrfs_fs_info *fs_info = dev->fs_info; |
7414a03f AJ |
643 | struct reada_extent *re = NULL; |
644 | int mirror_num = 0; | |
645 | struct extent_buffer *eb = NULL; | |
646 | u64 logical; | |
7414a03f AJ |
647 | int ret; |
648 | int i; | |
7414a03f AJ |
649 | |
650 | spin_lock(&fs_info->reada_lock); | |
651 | if (dev->reada_curr_zone == NULL) { | |
652 | ret = reada_pick_zone(dev); | |
653 | if (!ret) { | |
654 | spin_unlock(&fs_info->reada_lock); | |
655 | return 0; | |
656 | } | |
657 | } | |
658 | /* | |
659 | * FIXME currently we issue the reads one extent at a time. If we have | |
660 | * a contiguous block of extents, we could also coagulate them or use | |
661 | * plugging to speed things up | |
662 | */ | |
663 | ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re, | |
09cbfeaf | 664 | dev->reada_next >> PAGE_SHIFT, 1); |
50378530 | 665 | if (ret == 0 || re->logical > dev->reada_curr_zone->end) { |
7414a03f AJ |
666 | ret = reada_pick_zone(dev); |
667 | if (!ret) { | |
668 | spin_unlock(&fs_info->reada_lock); | |
669 | return 0; | |
670 | } | |
671 | re = NULL; | |
672 | ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re, | |
09cbfeaf | 673 | dev->reada_next >> PAGE_SHIFT, 1); |
7414a03f AJ |
674 | } |
675 | if (ret == 0) { | |
676 | spin_unlock(&fs_info->reada_lock); | |
677 | return 0; | |
678 | } | |
da17066c | 679 | dev->reada_next = re->logical + fs_info->nodesize; |
99621b44 | 680 | re->refcnt++; |
7414a03f AJ |
681 | |
682 | spin_unlock(&fs_info->reada_lock); | |
683 | ||
a3f7fde2 | 684 | spin_lock(&re->lock); |
895a11b8 | 685 | if (re->scheduled || list_empty(&re->extctl)) { |
a3f7fde2 ZL |
686 | spin_unlock(&re->lock); |
687 | reada_extent_put(fs_info, re); | |
688 | return 0; | |
689 | } | |
895a11b8 | 690 | re->scheduled = 1; |
a3f7fde2 ZL |
691 | spin_unlock(&re->lock); |
692 | ||
7414a03f AJ |
693 | /* |
694 | * find mirror num | |
695 | */ | |
696 | for (i = 0; i < re->nzones; ++i) { | |
697 | if (re->zones[i]->device == dev) { | |
698 | mirror_num = i + 1; | |
699 | break; | |
700 | } | |
701 | } | |
702 | logical = re->logical; | |
7414a03f | 703 | |
7414a03f | 704 | atomic_inc(&dev->reada_in_flight); |
2ff7e61e | 705 | ret = reada_tree_block_flagged(fs_info, logical, mirror_num, &eb); |
7414a03f | 706 | if (ret) |
bcdc51b2 | 707 | __readahead_hook(fs_info, re, NULL, ret); |
7414a03f | 708 | else if (eb) |
bcdc51b2 | 709 | __readahead_hook(fs_info, re, eb, ret); |
7414a03f AJ |
710 | |
711 | if (eb) | |
712 | free_extent_buffer(eb); | |
713 | ||
895a11b8 | 714 | atomic_dec(&dev->reada_in_flight); |
b257cf50 ZL |
715 | reada_extent_put(fs_info, re); |
716 | ||
7414a03f AJ |
717 | return 1; |
718 | ||
719 | } | |
720 | ||
d458b054 | 721 | static void reada_start_machine_worker(struct btrfs_work *work) |
7414a03f AJ |
722 | { |
723 | struct reada_machine_work *rmw; | |
724 | struct btrfs_fs_info *fs_info; | |
3d136a11 | 725 | int old_ioprio; |
7414a03f AJ |
726 | |
727 | rmw = container_of(work, struct reada_machine_work, work); | |
728 | fs_info = rmw->fs_info; | |
729 | ||
730 | kfree(rmw); | |
731 | ||
3d136a11 SB |
732 | old_ioprio = IOPRIO_PRIO_VALUE(task_nice_ioclass(current), |
733 | task_nice_ioprio(current)); | |
734 | set_task_ioprio(current, BTRFS_IOPRIO_READA); | |
7414a03f | 735 | __reada_start_machine(fs_info); |
3d136a11 | 736 | set_task_ioprio(current, old_ioprio); |
2fefd558 ZL |
737 | |
738 | atomic_dec(&fs_info->reada_works_cnt); | |
7414a03f AJ |
739 | } |
740 | ||
741 | static void __reada_start_machine(struct btrfs_fs_info *fs_info) | |
742 | { | |
743 | struct btrfs_device *device; | |
744 | struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; | |
745 | u64 enqueued; | |
746 | u64 total = 0; | |
747 | int i; | |
748 | ||
749 | do { | |
750 | enqueued = 0; | |
ce7791ff | 751 | mutex_lock(&fs_devices->device_list_mutex); |
7414a03f AJ |
752 | list_for_each_entry(device, &fs_devices->devices, dev_list) { |
753 | if (atomic_read(&device->reada_in_flight) < | |
754 | MAX_IN_FLIGHT) | |
5721b8ad | 755 | enqueued += reada_start_machine_dev(device); |
7414a03f | 756 | } |
ce7791ff | 757 | mutex_unlock(&fs_devices->device_list_mutex); |
7414a03f AJ |
758 | total += enqueued; |
759 | } while (enqueued && total < 10000); | |
760 | ||
761 | if (enqueued == 0) | |
762 | return; | |
763 | ||
764 | /* | |
765 | * If everything is already in the cache, this is effectively single | |
766 | * threaded. To a) not hold the caller for too long and b) to utilize | |
767 | * more cores, we broke the loop above after 10000 iterations and now | |
768 | * enqueue to workers to finish it. This will distribute the load to | |
769 | * the cores. | |
770 | */ | |
2fefd558 | 771 | for (i = 0; i < 2; ++i) { |
7414a03f | 772 | reada_start_machine(fs_info); |
2fefd558 ZL |
773 | if (atomic_read(&fs_info->reada_works_cnt) > |
774 | BTRFS_MAX_MIRRORS * 2) | |
775 | break; | |
776 | } | |
7414a03f AJ |
777 | } |
778 | ||
779 | static void reada_start_machine(struct btrfs_fs_info *fs_info) | |
780 | { | |
781 | struct reada_machine_work *rmw; | |
782 | ||
ed0244fa | 783 | rmw = kzalloc(sizeof(*rmw), GFP_KERNEL); |
7414a03f AJ |
784 | if (!rmw) { |
785 | /* FIXME we cannot handle this properly right now */ | |
786 | BUG(); | |
787 | } | |
9e0af237 LB |
788 | btrfs_init_work(&rmw->work, btrfs_readahead_helper, |
789 | reada_start_machine_worker, NULL, NULL); | |
7414a03f AJ |
790 | rmw->fs_info = fs_info; |
791 | ||
736cfa15 | 792 | btrfs_queue_work(fs_info->readahead_workers, &rmw->work); |
2fefd558 | 793 | atomic_inc(&fs_info->reada_works_cnt); |
7414a03f AJ |
794 | } |
795 | ||
796 | #ifdef DEBUG | |
797 | static void dump_devs(struct btrfs_fs_info *fs_info, int all) | |
798 | { | |
799 | struct btrfs_device *device; | |
800 | struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; | |
801 | unsigned long index; | |
802 | int ret; | |
803 | int i; | |
804 | int j; | |
805 | int cnt; | |
806 | ||
807 | spin_lock(&fs_info->reada_lock); | |
808 | list_for_each_entry(device, &fs_devices->devices, dev_list) { | |
ab8d0fc4 | 809 | btrfs_debug(fs_info, "dev %lld has %d in flight", device->devid, |
7414a03f AJ |
810 | atomic_read(&device->reada_in_flight)); |
811 | index = 0; | |
812 | while (1) { | |
813 | struct reada_zone *zone; | |
814 | ret = radix_tree_gang_lookup(&device->reada_zones, | |
815 | (void **)&zone, index, 1); | |
816 | if (ret == 0) | |
817 | break; | |
62e85577 | 818 | pr_debug(" zone %llu-%llu elems %llu locked %d devs", |
ab8d0fc4 JM |
819 | zone->start, zone->end, zone->elems, |
820 | zone->locked); | |
7414a03f | 821 | for (j = 0; j < zone->ndevs; ++j) { |
62e85577 | 822 | pr_cont(" %lld", |
7414a03f AJ |
823 | zone->devs[j]->devid); |
824 | } | |
825 | if (device->reada_curr_zone == zone) | |
62e85577 | 826 | pr_cont(" curr off %llu", |
7414a03f | 827 | device->reada_next - zone->start); |
62e85577 | 828 | pr_cont("\n"); |
09cbfeaf | 829 | index = (zone->end >> PAGE_SHIFT) + 1; |
7414a03f AJ |
830 | } |
831 | cnt = 0; | |
832 | index = 0; | |
833 | while (all) { | |
834 | struct reada_extent *re = NULL; | |
835 | ||
836 | ret = radix_tree_gang_lookup(&device->reada_extents, | |
837 | (void **)&re, index, 1); | |
838 | if (ret == 0) | |
839 | break; | |
62e85577 | 840 | pr_debug(" re: logical %llu size %u empty %d scheduled %d", |
da17066c | 841 | re->logical, fs_info->nodesize, |
895a11b8 | 842 | list_empty(&re->extctl), re->scheduled); |
7414a03f AJ |
843 | |
844 | for (i = 0; i < re->nzones; ++i) { | |
62e85577 | 845 | pr_cont(" zone %llu-%llu devs", |
7414a03f AJ |
846 | re->zones[i]->start, |
847 | re->zones[i]->end); | |
848 | for (j = 0; j < re->zones[i]->ndevs; ++j) { | |
62e85577 | 849 | pr_cont(" %lld", |
7414a03f AJ |
850 | re->zones[i]->devs[j]->devid); |
851 | } | |
852 | } | |
62e85577 | 853 | pr_cont("\n"); |
09cbfeaf | 854 | index = (re->logical >> PAGE_SHIFT) + 1; |
7414a03f AJ |
855 | if (++cnt > 15) |
856 | break; | |
857 | } | |
858 | } | |
859 | ||
860 | index = 0; | |
861 | cnt = 0; | |
862 | while (all) { | |
863 | struct reada_extent *re = NULL; | |
864 | ||
865 | ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re, | |
866 | index, 1); | |
867 | if (ret == 0) | |
868 | break; | |
895a11b8 | 869 | if (!re->scheduled) { |
09cbfeaf | 870 | index = (re->logical >> PAGE_SHIFT) + 1; |
7414a03f AJ |
871 | continue; |
872 | } | |
62e85577 | 873 | pr_debug("re: logical %llu size %u list empty %d scheduled %d", |
da17066c | 874 | re->logical, fs_info->nodesize, |
895a11b8 | 875 | list_empty(&re->extctl), re->scheduled); |
7414a03f | 876 | for (i = 0; i < re->nzones; ++i) { |
62e85577 | 877 | pr_cont(" zone %llu-%llu devs", |
7414a03f AJ |
878 | re->zones[i]->start, |
879 | re->zones[i]->end); | |
8afd6841 | 880 | for (j = 0; j < re->zones[i]->ndevs; ++j) { |
62e85577 | 881 | pr_cont(" %lld", |
8afd6841 | 882 | re->zones[i]->devs[j]->devid); |
7414a03f AJ |
883 | } |
884 | } | |
62e85577 | 885 | pr_cont("\n"); |
09cbfeaf | 886 | index = (re->logical >> PAGE_SHIFT) + 1; |
7414a03f AJ |
887 | } |
888 | spin_unlock(&fs_info->reada_lock); | |
889 | } | |
890 | #endif | |
891 | ||
892 | /* | |
893 | * interface | |
894 | */ | |
895 | struct reada_control *btrfs_reada_add(struct btrfs_root *root, | |
896 | struct btrfs_key *key_start, struct btrfs_key *key_end) | |
897 | { | |
898 | struct reada_control *rc; | |
899 | u64 start; | |
900 | u64 generation; | |
ddd664f4 | 901 | int ret; |
7414a03f AJ |
902 | struct extent_buffer *node; |
903 | static struct btrfs_key max_key = { | |
904 | .objectid = (u64)-1, | |
905 | .type = (u8)-1, | |
906 | .offset = (u64)-1 | |
907 | }; | |
908 | ||
ed0244fa | 909 | rc = kzalloc(sizeof(*rc), GFP_KERNEL); |
7414a03f AJ |
910 | if (!rc) |
911 | return ERR_PTR(-ENOMEM); | |
912 | ||
c28f158e | 913 | rc->fs_info = root->fs_info; |
7414a03f AJ |
914 | rc->key_start = *key_start; |
915 | rc->key_end = *key_end; | |
916 | atomic_set(&rc->elems, 0); | |
917 | init_waitqueue_head(&rc->wait); | |
918 | kref_init(&rc->refcnt); | |
919 | kref_get(&rc->refcnt); /* one ref for having elements */ | |
920 | ||
921 | node = btrfs_root_node(root); | |
922 | start = node->start; | |
7414a03f AJ |
923 | generation = btrfs_header_generation(node); |
924 | free_extent_buffer(node); | |
925 | ||
1e7970c0 | 926 | ret = reada_add_block(rc, start, &max_key, generation); |
ddd664f4 | 927 | if (ret) { |
ff023aac | 928 | kfree(rc); |
ddd664f4 | 929 | return ERR_PTR(ret); |
ff023aac | 930 | } |
7414a03f AJ |
931 | |
932 | reada_start_machine(root->fs_info); | |
933 | ||
934 | return rc; | |
935 | } | |
936 | ||
937 | #ifdef DEBUG | |
938 | int btrfs_reada_wait(void *handle) | |
939 | { | |
940 | struct reada_control *rc = handle; | |
c28f158e | 941 | struct btrfs_fs_info *fs_info = rc->fs_info; |
7414a03f AJ |
942 | |
943 | while (atomic_read(&rc->elems)) { | |
4fe7a0e1 ZL |
944 | if (!atomic_read(&fs_info->reada_works_cnt)) |
945 | reada_start_machine(fs_info); | |
7414a03f AJ |
946 | wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0, |
947 | 5 * HZ); | |
0b246afa | 948 | dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0); |
7414a03f AJ |
949 | } |
950 | ||
0b246afa | 951 | dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0); |
7414a03f AJ |
952 | |
953 | kref_put(&rc->refcnt, reada_control_release); | |
954 | ||
955 | return 0; | |
956 | } | |
957 | #else | |
958 | int btrfs_reada_wait(void *handle) | |
959 | { | |
960 | struct reada_control *rc = handle; | |
c28f158e | 961 | struct btrfs_fs_info *fs_info = rc->fs_info; |
7414a03f AJ |
962 | |
963 | while (atomic_read(&rc->elems)) { | |
4fe7a0e1 ZL |
964 | if (!atomic_read(&fs_info->reada_works_cnt)) |
965 | reada_start_machine(fs_info); | |
966 | wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0, | |
967 | (HZ + 9) / 10); | |
7414a03f AJ |
968 | } |
969 | ||
970 | kref_put(&rc->refcnt, reada_control_release); | |
971 | ||
972 | return 0; | |
973 | } | |
974 | #endif | |
975 | ||
976 | void btrfs_reada_detach(void *handle) | |
977 | { | |
978 | struct reada_control *rc = handle; | |
979 | ||
980 | kref_put(&rc->refcnt, reada_control_release); | |
981 | } |