Commit | Line | Data |
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7414a03f AJ |
1 | /* |
2 | * Copyright (C) 2011 STRATO. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/sched.h> | |
20 | #include <linux/pagemap.h> | |
21 | #include <linux/writeback.h> | |
22 | #include <linux/blkdev.h> | |
23 | #include <linux/rbtree.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/workqueue.h> | |
26 | #include "ctree.h" | |
27 | #include "volumes.h" | |
28 | #include "disk-io.h" | |
29 | #include "transaction.h" | |
8dabb742 | 30 | #include "dev-replace.h" |
7414a03f AJ |
31 | |
32 | #undef DEBUG | |
33 | ||
34 | /* | |
35 | * This is the implementation for the generic read ahead framework. | |
36 | * | |
37 | * To trigger a readahead, btrfs_reada_add must be called. It will start | |
38 | * a read ahead for the given range [start, end) on tree root. The returned | |
39 | * handle can either be used to wait on the readahead to finish | |
40 | * (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach). | |
41 | * | |
42 | * The read ahead works as follows: | |
43 | * On btrfs_reada_add, the root of the tree is inserted into a radix_tree. | |
44 | * reada_start_machine will then search for extents to prefetch and trigger | |
45 | * some reads. When a read finishes for a node, all contained node/leaf | |
46 | * pointers that lie in the given range will also be enqueued. The reads will | |
47 | * be triggered in sequential order, thus giving a big win over a naive | |
48 | * enumeration. It will also make use of multi-device layouts. Each disk | |
49 | * will have its on read pointer and all disks will by utilized in parallel. | |
50 | * Also will no two disks read both sides of a mirror simultaneously, as this | |
51 | * would waste seeking capacity. Instead both disks will read different parts | |
52 | * of the filesystem. | |
53 | * Any number of readaheads can be started in parallel. The read order will be | |
54 | * determined globally, i.e. 2 parallel readaheads will normally finish faster | |
55 | * than the 2 started one after another. | |
56 | */ | |
57 | ||
7414a03f AJ |
58 | #define MAX_IN_FLIGHT 6 |
59 | ||
60 | struct reada_extctl { | |
61 | struct list_head list; | |
62 | struct reada_control *rc; | |
63 | u64 generation; | |
64 | }; | |
65 | ||
66 | struct reada_extent { | |
67 | u64 logical; | |
68 | struct btrfs_key top; | |
69 | u32 blocksize; | |
70 | int err; | |
71 | struct list_head extctl; | |
99621b44 | 72 | int refcnt; |
7414a03f | 73 | spinlock_t lock; |
94598ba8 | 74 | struct reada_zone *zones[BTRFS_MAX_MIRRORS]; |
7414a03f AJ |
75 | int nzones; |
76 | struct btrfs_device *scheduled_for; | |
77 | }; | |
78 | ||
79 | struct reada_zone { | |
80 | u64 start; | |
81 | u64 end; | |
82 | u64 elems; | |
83 | struct list_head list; | |
84 | spinlock_t lock; | |
85 | int locked; | |
86 | struct btrfs_device *device; | |
94598ba8 SB |
87 | struct btrfs_device *devs[BTRFS_MAX_MIRRORS]; /* full list, incl |
88 | * self */ | |
7414a03f AJ |
89 | int ndevs; |
90 | struct kref refcnt; | |
91 | }; | |
92 | ||
93 | struct reada_machine_work { | |
d458b054 | 94 | struct btrfs_work work; |
7414a03f AJ |
95 | struct btrfs_fs_info *fs_info; |
96 | }; | |
97 | ||
98 | static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *); | |
99 | static void reada_control_release(struct kref *kref); | |
100 | static void reada_zone_release(struct kref *kref); | |
101 | static void reada_start_machine(struct btrfs_fs_info *fs_info); | |
102 | static void __reada_start_machine(struct btrfs_fs_info *fs_info); | |
103 | ||
104 | static int reada_add_block(struct reada_control *rc, u64 logical, | |
105 | struct btrfs_key *top, int level, u64 generation); | |
106 | ||
107 | /* recurses */ | |
108 | /* in case of err, eb might be NULL */ | |
109 | static int __readahead_hook(struct btrfs_root *root, struct extent_buffer *eb, | |
110 | u64 start, int err) | |
111 | { | |
112 | int level = 0; | |
113 | int nritems; | |
114 | int i; | |
115 | u64 bytenr; | |
116 | u64 generation; | |
117 | struct reada_extent *re; | |
118 | struct btrfs_fs_info *fs_info = root->fs_info; | |
119 | struct list_head list; | |
120 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
121 | struct btrfs_device *for_dev; | |
122 | ||
123 | if (eb) | |
124 | level = btrfs_header_level(eb); | |
125 | ||
126 | /* find extent */ | |
127 | spin_lock(&fs_info->reada_lock); | |
128 | re = radix_tree_lookup(&fs_info->reada_tree, index); | |
129 | if (re) | |
99621b44 | 130 | re->refcnt++; |
7414a03f AJ |
131 | spin_unlock(&fs_info->reada_lock); |
132 | ||
133 | if (!re) | |
134 | return -1; | |
135 | ||
136 | spin_lock(&re->lock); | |
137 | /* | |
138 | * just take the full list from the extent. afterwards we | |
139 | * don't need the lock anymore | |
140 | */ | |
141 | list_replace_init(&re->extctl, &list); | |
142 | for_dev = re->scheduled_for; | |
143 | re->scheduled_for = NULL; | |
144 | spin_unlock(&re->lock); | |
145 | ||
146 | if (err == 0) { | |
147 | nritems = level ? btrfs_header_nritems(eb) : 0; | |
148 | generation = btrfs_header_generation(eb); | |
149 | /* | |
150 | * FIXME: currently we just set nritems to 0 if this is a leaf, | |
151 | * effectively ignoring the content. In a next step we could | |
152 | * trigger more readahead depending from the content, e.g. | |
153 | * fetch the checksums for the extents in the leaf. | |
154 | */ | |
155 | } else { | |
156 | /* | |
157 | * this is the error case, the extent buffer has not been | |
158 | * read correctly. We won't access anything from it and | |
159 | * just cleanup our data structures. Effectively this will | |
160 | * cut the branch below this node from read ahead. | |
161 | */ | |
162 | nritems = 0; | |
163 | generation = 0; | |
164 | } | |
165 | ||
166 | for (i = 0; i < nritems; i++) { | |
167 | struct reada_extctl *rec; | |
168 | u64 n_gen; | |
169 | struct btrfs_key key; | |
170 | struct btrfs_key next_key; | |
171 | ||
172 | btrfs_node_key_to_cpu(eb, &key, i); | |
173 | if (i + 1 < nritems) | |
174 | btrfs_node_key_to_cpu(eb, &next_key, i + 1); | |
175 | else | |
176 | next_key = re->top; | |
177 | bytenr = btrfs_node_blockptr(eb, i); | |
178 | n_gen = btrfs_node_ptr_generation(eb, i); | |
179 | ||
180 | list_for_each_entry(rec, &list, list) { | |
181 | struct reada_control *rc = rec->rc; | |
182 | ||
183 | /* | |
184 | * if the generation doesn't match, just ignore this | |
185 | * extctl. This will probably cut off a branch from | |
186 | * prefetch. Alternatively one could start a new (sub-) | |
187 | * prefetch for this branch, starting again from root. | |
188 | * FIXME: move the generation check out of this loop | |
189 | */ | |
190 | #ifdef DEBUG | |
191 | if (rec->generation != generation) { | |
efe120a0 FH |
192 | btrfs_debug(root->fs_info, |
193 | "generation mismatch for (%llu,%d,%llu) %llu != %llu", | |
7414a03f AJ |
194 | key.objectid, key.type, key.offset, |
195 | rec->generation, generation); | |
196 | } | |
197 | #endif | |
198 | if (rec->generation == generation && | |
199 | btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 && | |
200 | btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0) | |
201 | reada_add_block(rc, bytenr, &next_key, | |
202 | level - 1, n_gen); | |
203 | } | |
204 | } | |
205 | /* | |
206 | * free extctl records | |
207 | */ | |
208 | while (!list_empty(&list)) { | |
209 | struct reada_control *rc; | |
210 | struct reada_extctl *rec; | |
211 | ||
212 | rec = list_first_entry(&list, struct reada_extctl, list); | |
213 | list_del(&rec->list); | |
214 | rc = rec->rc; | |
215 | kfree(rec); | |
216 | ||
217 | kref_get(&rc->refcnt); | |
218 | if (atomic_dec_and_test(&rc->elems)) { | |
219 | kref_put(&rc->refcnt, reada_control_release); | |
220 | wake_up(&rc->wait); | |
221 | } | |
222 | kref_put(&rc->refcnt, reada_control_release); | |
223 | ||
224 | reada_extent_put(fs_info, re); /* one ref for each entry */ | |
225 | } | |
226 | reada_extent_put(fs_info, re); /* our ref */ | |
227 | if (for_dev) | |
228 | atomic_dec(&for_dev->reada_in_flight); | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | /* | |
234 | * start is passed separately in case eb in NULL, which may be the case with | |
235 | * failed I/O | |
236 | */ | |
237 | int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb, | |
238 | u64 start, int err) | |
239 | { | |
240 | int ret; | |
241 | ||
242 | ret = __readahead_hook(root, eb, start, err); | |
243 | ||
244 | reada_start_machine(root->fs_info); | |
245 | ||
246 | return ret; | |
247 | } | |
248 | ||
249 | static struct reada_zone *reada_find_zone(struct btrfs_fs_info *fs_info, | |
250 | struct btrfs_device *dev, u64 logical, | |
21ca543e | 251 | struct btrfs_bio *bbio) |
7414a03f AJ |
252 | { |
253 | int ret; | |
7414a03f AJ |
254 | struct reada_zone *zone; |
255 | struct btrfs_block_group_cache *cache = NULL; | |
256 | u64 start; | |
257 | u64 end; | |
258 | int i; | |
259 | ||
7414a03f AJ |
260 | zone = NULL; |
261 | spin_lock(&fs_info->reada_lock); | |
262 | ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone, | |
263 | logical >> PAGE_CACHE_SHIFT, 1); | |
264 | if (ret == 1) | |
265 | kref_get(&zone->refcnt); | |
266 | spin_unlock(&fs_info->reada_lock); | |
267 | ||
268 | if (ret == 1) { | |
269 | if (logical >= zone->start && logical < zone->end) | |
270 | return zone; | |
271 | spin_lock(&fs_info->reada_lock); | |
272 | kref_put(&zone->refcnt, reada_zone_release); | |
273 | spin_unlock(&fs_info->reada_lock); | |
274 | } | |
275 | ||
7414a03f AJ |
276 | cache = btrfs_lookup_block_group(fs_info, logical); |
277 | if (!cache) | |
278 | return NULL; | |
279 | ||
280 | start = cache->key.objectid; | |
281 | end = start + cache->key.offset - 1; | |
282 | btrfs_put_block_group(cache); | |
283 | ||
284 | zone = kzalloc(sizeof(*zone), GFP_NOFS); | |
285 | if (!zone) | |
286 | return NULL; | |
287 | ||
288 | zone->start = start; | |
289 | zone->end = end; | |
290 | INIT_LIST_HEAD(&zone->list); | |
291 | spin_lock_init(&zone->lock); | |
292 | zone->locked = 0; | |
293 | kref_init(&zone->refcnt); | |
294 | zone->elems = 0; | |
295 | zone->device = dev; /* our device always sits at index 0 */ | |
21ca543e | 296 | for (i = 0; i < bbio->num_stripes; ++i) { |
7414a03f | 297 | /* bounds have already been checked */ |
21ca543e | 298 | zone->devs[i] = bbio->stripes[i].dev; |
7414a03f | 299 | } |
21ca543e | 300 | zone->ndevs = bbio->num_stripes; |
7414a03f AJ |
301 | |
302 | spin_lock(&fs_info->reada_lock); | |
303 | ret = radix_tree_insert(&dev->reada_zones, | |
a175423c | 304 | (unsigned long)(zone->end >> PAGE_CACHE_SHIFT), |
7414a03f | 305 | zone); |
7414a03f | 306 | |
8c9c2bf7 | 307 | if (ret == -EEXIST) { |
7414a03f | 308 | kfree(zone); |
8c9c2bf7 AJ |
309 | ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone, |
310 | logical >> PAGE_CACHE_SHIFT, 1); | |
311 | if (ret == 1) | |
312 | kref_get(&zone->refcnt); | |
7414a03f | 313 | } |
8c9c2bf7 | 314 | spin_unlock(&fs_info->reada_lock); |
7414a03f AJ |
315 | |
316 | return zone; | |
317 | } | |
318 | ||
319 | static struct reada_extent *reada_find_extent(struct btrfs_root *root, | |
320 | u64 logical, | |
321 | struct btrfs_key *top, int level) | |
322 | { | |
323 | int ret; | |
7414a03f | 324 | struct reada_extent *re = NULL; |
8c9c2bf7 | 325 | struct reada_extent *re_exist = NULL; |
7414a03f | 326 | struct btrfs_fs_info *fs_info = root->fs_info; |
21ca543e | 327 | struct btrfs_bio *bbio = NULL; |
7414a03f | 328 | struct btrfs_device *dev; |
207a232c | 329 | struct btrfs_device *prev_dev; |
7414a03f AJ |
330 | u32 blocksize; |
331 | u64 length; | |
332 | int nzones = 0; | |
333 | int i; | |
334 | unsigned long index = logical >> PAGE_CACHE_SHIFT; | |
8dabb742 | 335 | int dev_replace_is_ongoing; |
7414a03f | 336 | |
7414a03f AJ |
337 | spin_lock(&fs_info->reada_lock); |
338 | re = radix_tree_lookup(&fs_info->reada_tree, index); | |
339 | if (re) | |
99621b44 | 340 | re->refcnt++; |
7414a03f AJ |
341 | spin_unlock(&fs_info->reada_lock); |
342 | ||
8c9c2bf7 | 343 | if (re) |
7414a03f AJ |
344 | return re; |
345 | ||
346 | re = kzalloc(sizeof(*re), GFP_NOFS); | |
347 | if (!re) | |
348 | return NULL; | |
349 | ||
350 | blocksize = btrfs_level_size(root, level); | |
351 | re->logical = logical; | |
352 | re->blocksize = blocksize; | |
353 | re->top = *top; | |
354 | INIT_LIST_HEAD(&re->extctl); | |
355 | spin_lock_init(&re->lock); | |
99621b44 | 356 | re->refcnt = 1; |
7414a03f AJ |
357 | |
358 | /* | |
359 | * map block | |
360 | */ | |
361 | length = blocksize; | |
29a8d9a0 SB |
362 | ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical, &length, |
363 | &bbio, 0); | |
21ca543e | 364 | if (ret || !bbio || length < blocksize) |
7414a03f AJ |
365 | goto error; |
366 | ||
94598ba8 | 367 | if (bbio->num_stripes > BTRFS_MAX_MIRRORS) { |
efe120a0 FH |
368 | btrfs_err(root->fs_info, |
369 | "readahead: more than %d copies not supported", | |
370 | BTRFS_MAX_MIRRORS); | |
7414a03f AJ |
371 | goto error; |
372 | } | |
373 | ||
21ca543e | 374 | for (nzones = 0; nzones < bbio->num_stripes; ++nzones) { |
7414a03f AJ |
375 | struct reada_zone *zone; |
376 | ||
21ca543e ID |
377 | dev = bbio->stripes[nzones].dev; |
378 | zone = reada_find_zone(fs_info, dev, logical, bbio); | |
7414a03f AJ |
379 | if (!zone) |
380 | break; | |
381 | ||
382 | re->zones[nzones] = zone; | |
383 | spin_lock(&zone->lock); | |
384 | if (!zone->elems) | |
385 | kref_get(&zone->refcnt); | |
386 | ++zone->elems; | |
387 | spin_unlock(&zone->lock); | |
388 | spin_lock(&fs_info->reada_lock); | |
389 | kref_put(&zone->refcnt, reada_zone_release); | |
390 | spin_unlock(&fs_info->reada_lock); | |
391 | } | |
392 | re->nzones = nzones; | |
393 | if (nzones == 0) { | |
394 | /* not a single zone found, error and out */ | |
395 | goto error; | |
396 | } | |
397 | ||
398 | /* insert extent in reada_tree + all per-device trees, all or nothing */ | |
8dabb742 | 399 | btrfs_dev_replace_lock(&fs_info->dev_replace); |
7414a03f AJ |
400 | spin_lock(&fs_info->reada_lock); |
401 | ret = radix_tree_insert(&fs_info->reada_tree, index, re); | |
8c9c2bf7 AJ |
402 | if (ret == -EEXIST) { |
403 | re_exist = radix_tree_lookup(&fs_info->reada_tree, index); | |
404 | BUG_ON(!re_exist); | |
99621b44 | 405 | re_exist->refcnt++; |
8c9c2bf7 | 406 | spin_unlock(&fs_info->reada_lock); |
8dabb742 | 407 | btrfs_dev_replace_unlock(&fs_info->dev_replace); |
8c9c2bf7 AJ |
408 | goto error; |
409 | } | |
7414a03f AJ |
410 | if (ret) { |
411 | spin_unlock(&fs_info->reada_lock); | |
8dabb742 | 412 | btrfs_dev_replace_unlock(&fs_info->dev_replace); |
7414a03f AJ |
413 | goto error; |
414 | } | |
207a232c | 415 | prev_dev = NULL; |
8dabb742 SB |
416 | dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing( |
417 | &fs_info->dev_replace); | |
7414a03f | 418 | for (i = 0; i < nzones; ++i) { |
21ca543e | 419 | dev = bbio->stripes[i].dev; |
207a232c AJ |
420 | if (dev == prev_dev) { |
421 | /* | |
422 | * in case of DUP, just add the first zone. As both | |
423 | * are on the same device, there's nothing to gain | |
424 | * from adding both. | |
425 | * Also, it wouldn't work, as the tree is per device | |
426 | * and adding would fail with EEXIST | |
427 | */ | |
428 | continue; | |
429 | } | |
ff023aac | 430 | if (!dev->bdev) { |
5fbc7c59 WS |
431 | /* |
432 | * cannot read ahead on missing device, but for RAID5/6, | |
433 | * REQ_GET_READ_MIRRORS return 1. So don't skip missing | |
434 | * device for such case. | |
435 | */ | |
436 | if (nzones > 1) | |
437 | continue; | |
ff023aac | 438 | } |
8dabb742 SB |
439 | if (dev_replace_is_ongoing && |
440 | dev == fs_info->dev_replace.tgtdev) { | |
441 | /* | |
442 | * as this device is selected for reading only as | |
443 | * a last resort, skip it for read ahead. | |
444 | */ | |
445 | continue; | |
446 | } | |
207a232c | 447 | prev_dev = dev; |
7414a03f AJ |
448 | ret = radix_tree_insert(&dev->reada_extents, index, re); |
449 | if (ret) { | |
450 | while (--i >= 0) { | |
21ca543e | 451 | dev = bbio->stripes[i].dev; |
7414a03f | 452 | BUG_ON(dev == NULL); |
ff023aac | 453 | /* ignore whether the entry was inserted */ |
7414a03f AJ |
454 | radix_tree_delete(&dev->reada_extents, index); |
455 | } | |
456 | BUG_ON(fs_info == NULL); | |
457 | radix_tree_delete(&fs_info->reada_tree, index); | |
458 | spin_unlock(&fs_info->reada_lock); | |
8dabb742 | 459 | btrfs_dev_replace_unlock(&fs_info->dev_replace); |
7414a03f AJ |
460 | goto error; |
461 | } | |
462 | } | |
463 | spin_unlock(&fs_info->reada_lock); | |
8dabb742 | 464 | btrfs_dev_replace_unlock(&fs_info->dev_replace); |
7414a03f | 465 | |
21ca543e | 466 | kfree(bbio); |
7414a03f AJ |
467 | return re; |
468 | ||
469 | error: | |
470 | while (nzones) { | |
471 | struct reada_zone *zone; | |
472 | ||
473 | --nzones; | |
474 | zone = re->zones[nzones]; | |
475 | kref_get(&zone->refcnt); | |
476 | spin_lock(&zone->lock); | |
477 | --zone->elems; | |
478 | if (zone->elems == 0) { | |
479 | /* | |
480 | * no fs_info->reada_lock needed, as this can't be | |
481 | * the last ref | |
482 | */ | |
483 | kref_put(&zone->refcnt, reada_zone_release); | |
484 | } | |
485 | spin_unlock(&zone->lock); | |
486 | ||
487 | spin_lock(&fs_info->reada_lock); | |
488 | kref_put(&zone->refcnt, reada_zone_release); | |
489 | spin_unlock(&fs_info->reada_lock); | |
490 | } | |
21ca543e | 491 | kfree(bbio); |
7414a03f | 492 | kfree(re); |
8c9c2bf7 | 493 | return re_exist; |
7414a03f AJ |
494 | } |
495 | ||
7414a03f AJ |
496 | static void reada_extent_put(struct btrfs_fs_info *fs_info, |
497 | struct reada_extent *re) | |
498 | { | |
499 | int i; | |
500 | unsigned long index = re->logical >> PAGE_CACHE_SHIFT; | |
501 | ||
502 | spin_lock(&fs_info->reada_lock); | |
99621b44 | 503 | if (--re->refcnt) { |
7414a03f AJ |
504 | spin_unlock(&fs_info->reada_lock); |
505 | return; | |
506 | } | |
507 | ||
508 | radix_tree_delete(&fs_info->reada_tree, index); | |
509 | for (i = 0; i < re->nzones; ++i) { | |
510 | struct reada_zone *zone = re->zones[i]; | |
511 | ||
512 | radix_tree_delete(&zone->device->reada_extents, index); | |
513 | } | |
514 | ||
515 | spin_unlock(&fs_info->reada_lock); | |
516 | ||
517 | for (i = 0; i < re->nzones; ++i) { | |
518 | struct reada_zone *zone = re->zones[i]; | |
519 | ||
520 | kref_get(&zone->refcnt); | |
521 | spin_lock(&zone->lock); | |
522 | --zone->elems; | |
523 | if (zone->elems == 0) { | |
524 | /* no fs_info->reada_lock needed, as this can't be | |
525 | * the last ref */ | |
526 | kref_put(&zone->refcnt, reada_zone_release); | |
527 | } | |
528 | spin_unlock(&zone->lock); | |
529 | ||
530 | spin_lock(&fs_info->reada_lock); | |
531 | kref_put(&zone->refcnt, reada_zone_release); | |
532 | spin_unlock(&fs_info->reada_lock); | |
533 | } | |
534 | if (re->scheduled_for) | |
535 | atomic_dec(&re->scheduled_for->reada_in_flight); | |
536 | ||
537 | kfree(re); | |
538 | } | |
539 | ||
540 | static void reada_zone_release(struct kref *kref) | |
541 | { | |
542 | struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt); | |
543 | ||
544 | radix_tree_delete(&zone->device->reada_zones, | |
545 | zone->end >> PAGE_CACHE_SHIFT); | |
546 | ||
547 | kfree(zone); | |
548 | } | |
549 | ||
550 | static void reada_control_release(struct kref *kref) | |
551 | { | |
552 | struct reada_control *rc = container_of(kref, struct reada_control, | |
553 | refcnt); | |
554 | ||
555 | kfree(rc); | |
556 | } | |
557 | ||
558 | static int reada_add_block(struct reada_control *rc, u64 logical, | |
559 | struct btrfs_key *top, int level, u64 generation) | |
560 | { | |
561 | struct btrfs_root *root = rc->root; | |
562 | struct reada_extent *re; | |
563 | struct reada_extctl *rec; | |
564 | ||
565 | re = reada_find_extent(root, logical, top, level); /* takes one ref */ | |
566 | if (!re) | |
567 | return -1; | |
568 | ||
569 | rec = kzalloc(sizeof(*rec), GFP_NOFS); | |
570 | if (!rec) { | |
571 | reada_extent_put(root->fs_info, re); | |
572 | return -1; | |
573 | } | |
574 | ||
575 | rec->rc = rc; | |
576 | rec->generation = generation; | |
577 | atomic_inc(&rc->elems); | |
578 | ||
579 | spin_lock(&re->lock); | |
580 | list_add_tail(&rec->list, &re->extctl); | |
581 | spin_unlock(&re->lock); | |
582 | ||
583 | /* leave the ref on the extent */ | |
584 | ||
585 | return 0; | |
586 | } | |
587 | ||
588 | /* | |
589 | * called with fs_info->reada_lock held | |
590 | */ | |
591 | static void reada_peer_zones_set_lock(struct reada_zone *zone, int lock) | |
592 | { | |
593 | int i; | |
594 | unsigned long index = zone->end >> PAGE_CACHE_SHIFT; | |
595 | ||
596 | for (i = 0; i < zone->ndevs; ++i) { | |
597 | struct reada_zone *peer; | |
598 | peer = radix_tree_lookup(&zone->devs[i]->reada_zones, index); | |
599 | if (peer && peer->device != zone->device) | |
600 | peer->locked = lock; | |
601 | } | |
602 | } | |
603 | ||
604 | /* | |
605 | * called with fs_info->reada_lock held | |
606 | */ | |
607 | static int reada_pick_zone(struct btrfs_device *dev) | |
608 | { | |
609 | struct reada_zone *top_zone = NULL; | |
610 | struct reada_zone *top_locked_zone = NULL; | |
611 | u64 top_elems = 0; | |
612 | u64 top_locked_elems = 0; | |
613 | unsigned long index = 0; | |
614 | int ret; | |
615 | ||
616 | if (dev->reada_curr_zone) { | |
617 | reada_peer_zones_set_lock(dev->reada_curr_zone, 0); | |
618 | kref_put(&dev->reada_curr_zone->refcnt, reada_zone_release); | |
619 | dev->reada_curr_zone = NULL; | |
620 | } | |
621 | /* pick the zone with the most elements */ | |
622 | while (1) { | |
623 | struct reada_zone *zone; | |
624 | ||
625 | ret = radix_tree_gang_lookup(&dev->reada_zones, | |
626 | (void **)&zone, index, 1); | |
627 | if (ret == 0) | |
628 | break; | |
629 | index = (zone->end >> PAGE_CACHE_SHIFT) + 1; | |
630 | if (zone->locked) { | |
631 | if (zone->elems > top_locked_elems) { | |
632 | top_locked_elems = zone->elems; | |
633 | top_locked_zone = zone; | |
634 | } | |
635 | } else { | |
636 | if (zone->elems > top_elems) { | |
637 | top_elems = zone->elems; | |
638 | top_zone = zone; | |
639 | } | |
640 | } | |
641 | } | |
642 | if (top_zone) | |
643 | dev->reada_curr_zone = top_zone; | |
644 | else if (top_locked_zone) | |
645 | dev->reada_curr_zone = top_locked_zone; | |
646 | else | |
647 | return 0; | |
648 | ||
649 | dev->reada_next = dev->reada_curr_zone->start; | |
650 | kref_get(&dev->reada_curr_zone->refcnt); | |
651 | reada_peer_zones_set_lock(dev->reada_curr_zone, 1); | |
652 | ||
653 | return 1; | |
654 | } | |
655 | ||
656 | static int reada_start_machine_dev(struct btrfs_fs_info *fs_info, | |
657 | struct btrfs_device *dev) | |
658 | { | |
659 | struct reada_extent *re = NULL; | |
660 | int mirror_num = 0; | |
661 | struct extent_buffer *eb = NULL; | |
662 | u64 logical; | |
663 | u32 blocksize; | |
664 | int ret; | |
665 | int i; | |
666 | int need_kick = 0; | |
667 | ||
668 | spin_lock(&fs_info->reada_lock); | |
669 | if (dev->reada_curr_zone == NULL) { | |
670 | ret = reada_pick_zone(dev); | |
671 | if (!ret) { | |
672 | spin_unlock(&fs_info->reada_lock); | |
673 | return 0; | |
674 | } | |
675 | } | |
676 | /* | |
677 | * FIXME currently we issue the reads one extent at a time. If we have | |
678 | * a contiguous block of extents, we could also coagulate them or use | |
679 | * plugging to speed things up | |
680 | */ | |
681 | ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re, | |
682 | dev->reada_next >> PAGE_CACHE_SHIFT, 1); | |
683 | if (ret == 0 || re->logical >= dev->reada_curr_zone->end) { | |
684 | ret = reada_pick_zone(dev); | |
685 | if (!ret) { | |
686 | spin_unlock(&fs_info->reada_lock); | |
687 | return 0; | |
688 | } | |
689 | re = NULL; | |
690 | ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re, | |
691 | dev->reada_next >> PAGE_CACHE_SHIFT, 1); | |
692 | } | |
693 | if (ret == 0) { | |
694 | spin_unlock(&fs_info->reada_lock); | |
695 | return 0; | |
696 | } | |
697 | dev->reada_next = re->logical + re->blocksize; | |
99621b44 | 698 | re->refcnt++; |
7414a03f AJ |
699 | |
700 | spin_unlock(&fs_info->reada_lock); | |
701 | ||
702 | /* | |
703 | * find mirror num | |
704 | */ | |
705 | for (i = 0; i < re->nzones; ++i) { | |
706 | if (re->zones[i]->device == dev) { | |
707 | mirror_num = i + 1; | |
708 | break; | |
709 | } | |
710 | } | |
711 | logical = re->logical; | |
712 | blocksize = re->blocksize; | |
713 | ||
714 | spin_lock(&re->lock); | |
715 | if (re->scheduled_for == NULL) { | |
716 | re->scheduled_for = dev; | |
717 | need_kick = 1; | |
718 | } | |
719 | spin_unlock(&re->lock); | |
720 | ||
721 | reada_extent_put(fs_info, re); | |
722 | ||
723 | if (!need_kick) | |
724 | return 0; | |
725 | ||
726 | atomic_inc(&dev->reada_in_flight); | |
727 | ret = reada_tree_block_flagged(fs_info->extent_root, logical, blocksize, | |
728 | mirror_num, &eb); | |
729 | if (ret) | |
730 | __readahead_hook(fs_info->extent_root, NULL, logical, ret); | |
731 | else if (eb) | |
732 | __readahead_hook(fs_info->extent_root, eb, eb->start, ret); | |
733 | ||
734 | if (eb) | |
735 | free_extent_buffer(eb); | |
736 | ||
737 | return 1; | |
738 | ||
739 | } | |
740 | ||
d458b054 | 741 | static void reada_start_machine_worker(struct btrfs_work *work) |
7414a03f AJ |
742 | { |
743 | struct reada_machine_work *rmw; | |
744 | struct btrfs_fs_info *fs_info; | |
3d136a11 | 745 | int old_ioprio; |
7414a03f AJ |
746 | |
747 | rmw = container_of(work, struct reada_machine_work, work); | |
748 | fs_info = rmw->fs_info; | |
749 | ||
750 | kfree(rmw); | |
751 | ||
3d136a11 SB |
752 | old_ioprio = IOPRIO_PRIO_VALUE(task_nice_ioclass(current), |
753 | task_nice_ioprio(current)); | |
754 | set_task_ioprio(current, BTRFS_IOPRIO_READA); | |
7414a03f | 755 | __reada_start_machine(fs_info); |
3d136a11 | 756 | set_task_ioprio(current, old_ioprio); |
7414a03f AJ |
757 | } |
758 | ||
759 | static void __reada_start_machine(struct btrfs_fs_info *fs_info) | |
760 | { | |
761 | struct btrfs_device *device; | |
762 | struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; | |
763 | u64 enqueued; | |
764 | u64 total = 0; | |
765 | int i; | |
766 | ||
767 | do { | |
768 | enqueued = 0; | |
769 | list_for_each_entry(device, &fs_devices->devices, dev_list) { | |
770 | if (atomic_read(&device->reada_in_flight) < | |
771 | MAX_IN_FLIGHT) | |
772 | enqueued += reada_start_machine_dev(fs_info, | |
773 | device); | |
774 | } | |
775 | total += enqueued; | |
776 | } while (enqueued && total < 10000); | |
777 | ||
778 | if (enqueued == 0) | |
779 | return; | |
780 | ||
781 | /* | |
782 | * If everything is already in the cache, this is effectively single | |
783 | * threaded. To a) not hold the caller for too long and b) to utilize | |
784 | * more cores, we broke the loop above after 10000 iterations and now | |
785 | * enqueue to workers to finish it. This will distribute the load to | |
786 | * the cores. | |
787 | */ | |
788 | for (i = 0; i < 2; ++i) | |
789 | reada_start_machine(fs_info); | |
790 | } | |
791 | ||
792 | static void reada_start_machine(struct btrfs_fs_info *fs_info) | |
793 | { | |
794 | struct reada_machine_work *rmw; | |
795 | ||
796 | rmw = kzalloc(sizeof(*rmw), GFP_NOFS); | |
797 | if (!rmw) { | |
798 | /* FIXME we cannot handle this properly right now */ | |
799 | BUG(); | |
800 | } | |
736cfa15 | 801 | btrfs_init_work(&rmw->work, reada_start_machine_worker, NULL, NULL); |
7414a03f AJ |
802 | rmw->fs_info = fs_info; |
803 | ||
736cfa15 | 804 | btrfs_queue_work(fs_info->readahead_workers, &rmw->work); |
7414a03f AJ |
805 | } |
806 | ||
807 | #ifdef DEBUG | |
808 | static void dump_devs(struct btrfs_fs_info *fs_info, int all) | |
809 | { | |
810 | struct btrfs_device *device; | |
811 | struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; | |
812 | unsigned long index; | |
813 | int ret; | |
814 | int i; | |
815 | int j; | |
816 | int cnt; | |
817 | ||
818 | spin_lock(&fs_info->reada_lock); | |
819 | list_for_each_entry(device, &fs_devices->devices, dev_list) { | |
820 | printk(KERN_DEBUG "dev %lld has %d in flight\n", device->devid, | |
821 | atomic_read(&device->reada_in_flight)); | |
822 | index = 0; | |
823 | while (1) { | |
824 | struct reada_zone *zone; | |
825 | ret = radix_tree_gang_lookup(&device->reada_zones, | |
826 | (void **)&zone, index, 1); | |
827 | if (ret == 0) | |
828 | break; | |
829 | printk(KERN_DEBUG " zone %llu-%llu elems %llu locked " | |
830 | "%d devs", zone->start, zone->end, zone->elems, | |
831 | zone->locked); | |
832 | for (j = 0; j < zone->ndevs; ++j) { | |
833 | printk(KERN_CONT " %lld", | |
834 | zone->devs[j]->devid); | |
835 | } | |
836 | if (device->reada_curr_zone == zone) | |
837 | printk(KERN_CONT " curr off %llu", | |
838 | device->reada_next - zone->start); | |
839 | printk(KERN_CONT "\n"); | |
840 | index = (zone->end >> PAGE_CACHE_SHIFT) + 1; | |
841 | } | |
842 | cnt = 0; | |
843 | index = 0; | |
844 | while (all) { | |
845 | struct reada_extent *re = NULL; | |
846 | ||
847 | ret = radix_tree_gang_lookup(&device->reada_extents, | |
848 | (void **)&re, index, 1); | |
849 | if (ret == 0) | |
850 | break; | |
851 | printk(KERN_DEBUG | |
852 | " re: logical %llu size %u empty %d for %lld", | |
853 | re->logical, re->blocksize, | |
854 | list_empty(&re->extctl), re->scheduled_for ? | |
855 | re->scheduled_for->devid : -1); | |
856 | ||
857 | for (i = 0; i < re->nzones; ++i) { | |
858 | printk(KERN_CONT " zone %llu-%llu devs", | |
859 | re->zones[i]->start, | |
860 | re->zones[i]->end); | |
861 | for (j = 0; j < re->zones[i]->ndevs; ++j) { | |
862 | printk(KERN_CONT " %lld", | |
863 | re->zones[i]->devs[j]->devid); | |
864 | } | |
865 | } | |
866 | printk(KERN_CONT "\n"); | |
867 | index = (re->logical >> PAGE_CACHE_SHIFT) + 1; | |
868 | if (++cnt > 15) | |
869 | break; | |
870 | } | |
871 | } | |
872 | ||
873 | index = 0; | |
874 | cnt = 0; | |
875 | while (all) { | |
876 | struct reada_extent *re = NULL; | |
877 | ||
878 | ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re, | |
879 | index, 1); | |
880 | if (ret == 0) | |
881 | break; | |
882 | if (!re->scheduled_for) { | |
883 | index = (re->logical >> PAGE_CACHE_SHIFT) + 1; | |
884 | continue; | |
885 | } | |
886 | printk(KERN_DEBUG | |
887 | "re: logical %llu size %u list empty %d for %lld", | |
888 | re->logical, re->blocksize, list_empty(&re->extctl), | |
889 | re->scheduled_for ? re->scheduled_for->devid : -1); | |
890 | for (i = 0; i < re->nzones; ++i) { | |
891 | printk(KERN_CONT " zone %llu-%llu devs", | |
892 | re->zones[i]->start, | |
893 | re->zones[i]->end); | |
894 | for (i = 0; i < re->nzones; ++i) { | |
895 | printk(KERN_CONT " zone %llu-%llu devs", | |
896 | re->zones[i]->start, | |
897 | re->zones[i]->end); | |
898 | for (j = 0; j < re->zones[i]->ndevs; ++j) { | |
899 | printk(KERN_CONT " %lld", | |
900 | re->zones[i]->devs[j]->devid); | |
901 | } | |
902 | } | |
903 | } | |
904 | printk(KERN_CONT "\n"); | |
905 | index = (re->logical >> PAGE_CACHE_SHIFT) + 1; | |
906 | } | |
907 | spin_unlock(&fs_info->reada_lock); | |
908 | } | |
909 | #endif | |
910 | ||
911 | /* | |
912 | * interface | |
913 | */ | |
914 | struct reada_control *btrfs_reada_add(struct btrfs_root *root, | |
915 | struct btrfs_key *key_start, struct btrfs_key *key_end) | |
916 | { | |
917 | struct reada_control *rc; | |
918 | u64 start; | |
919 | u64 generation; | |
920 | int level; | |
921 | struct extent_buffer *node; | |
922 | static struct btrfs_key max_key = { | |
923 | .objectid = (u64)-1, | |
924 | .type = (u8)-1, | |
925 | .offset = (u64)-1 | |
926 | }; | |
927 | ||
928 | rc = kzalloc(sizeof(*rc), GFP_NOFS); | |
929 | if (!rc) | |
930 | return ERR_PTR(-ENOMEM); | |
931 | ||
932 | rc->root = root; | |
933 | rc->key_start = *key_start; | |
934 | rc->key_end = *key_end; | |
935 | atomic_set(&rc->elems, 0); | |
936 | init_waitqueue_head(&rc->wait); | |
937 | kref_init(&rc->refcnt); | |
938 | kref_get(&rc->refcnt); /* one ref for having elements */ | |
939 | ||
940 | node = btrfs_root_node(root); | |
941 | start = node->start; | |
942 | level = btrfs_header_level(node); | |
943 | generation = btrfs_header_generation(node); | |
944 | free_extent_buffer(node); | |
945 | ||
ff023aac SB |
946 | if (reada_add_block(rc, start, &max_key, level, generation)) { |
947 | kfree(rc); | |
948 | return ERR_PTR(-ENOMEM); | |
949 | } | |
7414a03f AJ |
950 | |
951 | reada_start_machine(root->fs_info); | |
952 | ||
953 | return rc; | |
954 | } | |
955 | ||
956 | #ifdef DEBUG | |
957 | int btrfs_reada_wait(void *handle) | |
958 | { | |
959 | struct reada_control *rc = handle; | |
960 | ||
961 | while (atomic_read(&rc->elems)) { | |
962 | wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0, | |
963 | 5 * HZ); | |
3c59ccd3 V |
964 | dump_devs(rc->root->fs_info, |
965 | atomic_read(&rc->elems) < 10 ? 1 : 0); | |
7414a03f AJ |
966 | } |
967 | ||
3c59ccd3 | 968 | dump_devs(rc->root->fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0); |
7414a03f AJ |
969 | |
970 | kref_put(&rc->refcnt, reada_control_release); | |
971 | ||
972 | return 0; | |
973 | } | |
974 | #else | |
975 | int btrfs_reada_wait(void *handle) | |
976 | { | |
977 | struct reada_control *rc = handle; | |
978 | ||
979 | while (atomic_read(&rc->elems)) { | |
980 | wait_event(rc->wait, atomic_read(&rc->elems) == 0); | |
981 | } | |
982 | ||
983 | kref_put(&rc->refcnt, reada_control_release); | |
984 | ||
985 | return 0; | |
986 | } | |
987 | #endif | |
988 | ||
989 | void btrfs_reada_detach(void *handle) | |
990 | { | |
991 | struct reada_control *rc = handle; | |
992 | ||
993 | kref_put(&rc->refcnt, reada_control_release); | |
994 | } |