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654598be ZL |
1 | /* |
2 | * fs/ext4/extents_status.c | |
3 | * | |
4 | * Written by Yongqiang Yang <xiaoqiangnk@gmail.com> | |
5 | * Modified by | |
6 | * Allison Henderson <achender@linux.vnet.ibm.com> | |
7 | * Hugh Dickins <hughd@google.com> | |
8 | * Zheng Liu <wenqing.lz@taobao.com> | |
9 | * | |
10 | * Ext4 extents status tree core functions. | |
11 | */ | |
12 | #include <linux/rbtree.h> | |
13 | #include "ext4.h" | |
14 | #include "extents_status.h" | |
15 | #include "ext4_extents.h" | |
16 | ||
992e9fdd ZL |
17 | #include <trace/events/ext4.h> |
18 | ||
654598be ZL |
19 | /* |
20 | * According to previous discussion in Ext4 Developer Workshop, we | |
21 | * will introduce a new structure called io tree to track all extent | |
22 | * status in order to solve some problems that we have met | |
23 | * (e.g. Reservation space warning), and provide extent-level locking. | |
24 | * Delay extent tree is the first step to achieve this goal. It is | |
25 | * original built by Yongqiang Yang. At that time it is called delay | |
06b0c886 | 26 | * extent tree, whose goal is only track delayed extents in memory to |
654598be ZL |
27 | * simplify the implementation of fiemap and bigalloc, and introduce |
28 | * lseek SEEK_DATA/SEEK_HOLE support. That is why it is still called | |
06b0c886 ZL |
29 | * delay extent tree at the first commit. But for better understand |
30 | * what it does, it has been rename to extent status tree. | |
654598be | 31 | * |
06b0c886 ZL |
32 | * Step1: |
33 | * Currently the first step has been done. All delayed extents are | |
34 | * tracked in the tree. It maintains the delayed extent when a delayed | |
35 | * allocation is issued, and the delayed extent is written out or | |
654598be ZL |
36 | * invalidated. Therefore the implementation of fiemap and bigalloc |
37 | * are simplified, and SEEK_DATA/SEEK_HOLE are introduced. | |
38 | * | |
39 | * The following comment describes the implemenmtation of extent | |
40 | * status tree and future works. | |
06b0c886 ZL |
41 | * |
42 | * Step2: | |
43 | * In this step all extent status are tracked by extent status tree. | |
44 | * Thus, we can first try to lookup a block mapping in this tree before | |
45 | * finding it in extent tree. Hence, single extent cache can be removed | |
46 | * because extent status tree can do a better job. Extents in status | |
47 | * tree are loaded on-demand. Therefore, the extent status tree may not | |
48 | * contain all of the extents in a file. Meanwhile we define a shrinker | |
49 | * to reclaim memory from extent status tree because fragmented extent | |
50 | * tree will make status tree cost too much memory. written/unwritten/- | |
51 | * hole extents in the tree will be reclaimed by this shrinker when we | |
52 | * are under high memory pressure. Delayed extents will not be | |
53 | * reclimed because fiemap, bigalloc, and seek_data/hole need it. | |
654598be ZL |
54 | */ |
55 | ||
56 | /* | |
06b0c886 | 57 | * Extent status tree implementation for ext4. |
654598be ZL |
58 | * |
59 | * | |
60 | * ========================================================================== | |
06b0c886 | 61 | * Extent status tree tracks all extent status. |
654598be | 62 | * |
06b0c886 | 63 | * 1. Why we need to implement extent status tree? |
654598be | 64 | * |
06b0c886 | 65 | * Without extent status tree, ext4 identifies a delayed extent by looking |
654598be ZL |
66 | * up page cache, this has several deficiencies - complicated, buggy, |
67 | * and inefficient code. | |
68 | * | |
06b0c886 ZL |
69 | * FIEMAP, SEEK_HOLE/DATA, bigalloc, and writeout all need to know if a |
70 | * block or a range of blocks are belonged to a delayed extent. | |
654598be | 71 | * |
06b0c886 | 72 | * Let us have a look at how they do without extent status tree. |
654598be ZL |
73 | * -- FIEMAP |
74 | * FIEMAP looks up page cache to identify delayed allocations from holes. | |
75 | * | |
76 | * -- SEEK_HOLE/DATA | |
77 | * SEEK_HOLE/DATA has the same problem as FIEMAP. | |
78 | * | |
79 | * -- bigalloc | |
80 | * bigalloc looks up page cache to figure out if a block is | |
81 | * already under delayed allocation or not to determine whether | |
82 | * quota reserving is needed for the cluster. | |
83 | * | |
654598be ZL |
84 | * -- writeout |
85 | * Writeout looks up whole page cache to see if a buffer is | |
86 | * mapped, If there are not very many delayed buffers, then it is | |
87 | * time comsuming. | |
88 | * | |
06b0c886 | 89 | * With extent status tree implementation, FIEMAP, SEEK_HOLE/DATA, |
654598be ZL |
90 | * bigalloc and writeout can figure out if a block or a range of |
91 | * blocks is under delayed allocation(belonged to a delayed extent) or | |
06b0c886 | 92 | * not by searching the extent tree. |
654598be ZL |
93 | * |
94 | * | |
95 | * ========================================================================== | |
06b0c886 ZL |
96 | * 2. Ext4 extent status tree impelmentation |
97 | * | |
98 | * -- extent | |
99 | * A extent is a range of blocks which are contiguous logically and | |
100 | * physically. Unlike extent in extent tree, this extent in ext4 is | |
101 | * a in-memory struct, there is no corresponding on-disk data. There | |
102 | * is no limit on length of extent, so an extent can contain as many | |
103 | * blocks as they are contiguous logically and physically. | |
654598be | 104 | * |
06b0c886 ZL |
105 | * -- extent status tree |
106 | * Every inode has an extent status tree and all allocation blocks | |
107 | * are added to the tree with different status. The extent in the | |
108 | * tree are ordered by logical block no. | |
654598be | 109 | * |
06b0c886 ZL |
110 | * -- operations on a extent status tree |
111 | * There are three important operations on a delayed extent tree: find | |
112 | * next extent, adding a extent(a range of blocks) and removing a extent. | |
654598be | 113 | * |
06b0c886 ZL |
114 | * -- race on a extent status tree |
115 | * Extent status tree is protected by inode->i_es_lock. | |
654598be | 116 | * |
06b0c886 ZL |
117 | * -- memory consumption |
118 | * Fragmented extent tree will make extent status tree cost too much | |
119 | * memory. Hence, we will reclaim written/unwritten/hole extents from | |
120 | * the tree under a heavy memory pressure. | |
654598be ZL |
121 | * |
122 | * | |
123 | * ========================================================================== | |
06b0c886 ZL |
124 | * 3. Performance analysis |
125 | * | |
654598be ZL |
126 | * -- overhead |
127 | * 1. There is a cache extent for write access, so if writes are | |
128 | * not very random, adding space operaions are in O(1) time. | |
129 | * | |
130 | * -- gain | |
131 | * 2. Code is much simpler, more readable, more maintainable and | |
132 | * more efficient. | |
133 | * | |
134 | * | |
135 | * ========================================================================== | |
136 | * 4. TODO list | |
654598be | 137 | * |
06b0c886 | 138 | * -- Refactor delayed space reservation |
654598be ZL |
139 | * |
140 | * -- Extent-level locking | |
141 | */ | |
142 | ||
143 | static struct kmem_cache *ext4_es_cachep; | |
144 | ||
bdedbb7b ZL |
145 | static int __es_insert_extent(struct inode *inode, struct extent_status *newes); |
146 | static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, | |
06b0c886 | 147 | ext4_lblk_t end); |
74cd15cd ZL |
148 | static int __es_try_to_reclaim_extents(struct ext4_inode_info *ei, |
149 | int nr_to_scan); | |
150 | static int ext4_es_reclaim_extents_count(struct super_block *sb); | |
06b0c886 | 151 | |
654598be ZL |
152 | int __init ext4_init_es(void) |
153 | { | |
154 | ext4_es_cachep = KMEM_CACHE(extent_status, SLAB_RECLAIM_ACCOUNT); | |
155 | if (ext4_es_cachep == NULL) | |
156 | return -ENOMEM; | |
157 | return 0; | |
158 | } | |
159 | ||
160 | void ext4_exit_es(void) | |
161 | { | |
162 | if (ext4_es_cachep) | |
163 | kmem_cache_destroy(ext4_es_cachep); | |
164 | } | |
165 | ||
166 | void ext4_es_init_tree(struct ext4_es_tree *tree) | |
167 | { | |
168 | tree->root = RB_ROOT; | |
169 | tree->cache_es = NULL; | |
170 | } | |
171 | ||
172 | #ifdef ES_DEBUG__ | |
173 | static void ext4_es_print_tree(struct inode *inode) | |
174 | { | |
175 | struct ext4_es_tree *tree; | |
176 | struct rb_node *node; | |
177 | ||
178 | printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino); | |
179 | tree = &EXT4_I(inode)->i_es_tree; | |
180 | node = rb_first(&tree->root); | |
181 | while (node) { | |
182 | struct extent_status *es; | |
183 | es = rb_entry(node, struct extent_status, rb_node); | |
fdc0212e ZL |
184 | printk(KERN_DEBUG " [%u/%u) %llu %llx", |
185 | es->es_lblk, es->es_len, | |
186 | ext4_es_pblock(es), ext4_es_status(es)); | |
654598be ZL |
187 | node = rb_next(node); |
188 | } | |
189 | printk(KERN_DEBUG "\n"); | |
190 | } | |
191 | #else | |
192 | #define ext4_es_print_tree(inode) | |
193 | #endif | |
194 | ||
06b0c886 | 195 | static inline ext4_lblk_t ext4_es_end(struct extent_status *es) |
654598be | 196 | { |
06b0c886 ZL |
197 | BUG_ON(es->es_lblk + es->es_len < es->es_lblk); |
198 | return es->es_lblk + es->es_len - 1; | |
654598be ZL |
199 | } |
200 | ||
201 | /* | |
202 | * search through the tree for an delayed extent with a given offset. If | |
203 | * it can't be found, try to find next extent. | |
204 | */ | |
205 | static struct extent_status *__es_tree_search(struct rb_root *root, | |
06b0c886 | 206 | ext4_lblk_t lblk) |
654598be ZL |
207 | { |
208 | struct rb_node *node = root->rb_node; | |
209 | struct extent_status *es = NULL; | |
210 | ||
211 | while (node) { | |
212 | es = rb_entry(node, struct extent_status, rb_node); | |
06b0c886 | 213 | if (lblk < es->es_lblk) |
654598be | 214 | node = node->rb_left; |
06b0c886 | 215 | else if (lblk > ext4_es_end(es)) |
654598be ZL |
216 | node = node->rb_right; |
217 | else | |
218 | return es; | |
219 | } | |
220 | ||
06b0c886 | 221 | if (es && lblk < es->es_lblk) |
654598be ZL |
222 | return es; |
223 | ||
06b0c886 | 224 | if (es && lblk > ext4_es_end(es)) { |
654598be ZL |
225 | node = rb_next(&es->rb_node); |
226 | return node ? rb_entry(node, struct extent_status, rb_node) : | |
227 | NULL; | |
228 | } | |
229 | ||
230 | return NULL; | |
231 | } | |
232 | ||
233 | /* | |
be401363 | 234 | * ext4_es_find_delayed_extent: find the 1st delayed extent covering @es->lblk |
06b0c886 | 235 | * if it exists, otherwise, the next extent after @es->lblk. |
654598be ZL |
236 | * |
237 | * @inode: the inode which owns delayed extents | |
be401363 | 238 | * @lblk: the offset where we start to search |
654598be | 239 | * @es: delayed extent that we found |
654598be | 240 | */ |
be401363 ZL |
241 | void ext4_es_find_delayed_extent(struct inode *inode, ext4_lblk_t lblk, |
242 | struct extent_status *es) | |
654598be ZL |
243 | { |
244 | struct ext4_es_tree *tree = NULL; | |
245 | struct extent_status *es1 = NULL; | |
246 | struct rb_node *node; | |
654598be | 247 | |
be401363 ZL |
248 | BUG_ON(es == NULL); |
249 | trace_ext4_es_find_delayed_extent_enter(inode, lblk); | |
992e9fdd | 250 | |
654598be ZL |
251 | read_lock(&EXT4_I(inode)->i_es_lock); |
252 | tree = &EXT4_I(inode)->i_es_tree; | |
253 | ||
fdc0212e | 254 | /* find extent in cache firstly */ |
be401363 | 255 | es->es_lblk = es->es_len = es->es_pblk = 0; |
654598be ZL |
256 | if (tree->cache_es) { |
257 | es1 = tree->cache_es; | |
be401363 | 258 | if (in_range(lblk, es1->es_lblk, es1->es_len)) { |
fdc0212e | 259 | es_debug("%u cached by [%u/%u) %llu %llx\n", |
be401363 | 260 | lblk, es1->es_lblk, es1->es_len, |
fdc0212e | 261 | ext4_es_pblock(es1), ext4_es_status(es1)); |
654598be ZL |
262 | goto out; |
263 | } | |
264 | } | |
265 | ||
be401363 | 266 | es1 = __es_tree_search(&tree->root, lblk); |
654598be ZL |
267 | |
268 | out: | |
be401363 ZL |
269 | if (es1 && !ext4_es_is_delayed(es1)) { |
270 | while ((node = rb_next(&es1->rb_node)) != NULL) { | |
271 | es1 = rb_entry(node, struct extent_status, rb_node); | |
272 | if (ext4_es_is_delayed(es1)) | |
273 | break; | |
274 | } | |
275 | } | |
276 | ||
277 | if (es1 && ext4_es_is_delayed(es1)) { | |
654598be | 278 | tree->cache_es = es1; |
06b0c886 ZL |
279 | es->es_lblk = es1->es_lblk; |
280 | es->es_len = es1->es_len; | |
fdc0212e | 281 | es->es_pblk = es1->es_pblk; |
654598be ZL |
282 | } |
283 | ||
284 | read_unlock(&EXT4_I(inode)->i_es_lock); | |
992e9fdd | 285 | |
74cd15cd | 286 | ext4_es_lru_add(inode); |
be401363 | 287 | trace_ext4_es_find_delayed_extent_exit(inode, es); |
654598be ZL |
288 | } |
289 | ||
290 | static struct extent_status * | |
bdedbb7b ZL |
291 | ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len, |
292 | ext4_fsblk_t pblk) | |
654598be ZL |
293 | { |
294 | struct extent_status *es; | |
295 | es = kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC); | |
296 | if (es == NULL) | |
297 | return NULL; | |
06b0c886 ZL |
298 | es->es_lblk = lblk; |
299 | es->es_len = len; | |
fdc0212e | 300 | es->es_pblk = pblk; |
74cd15cd ZL |
301 | |
302 | /* | |
303 | * We don't count delayed extent because we never try to reclaim them | |
304 | */ | |
305 | if (!ext4_es_is_delayed(es)) | |
306 | EXT4_I(inode)->i_es_lru_nr++; | |
307 | ||
654598be ZL |
308 | return es; |
309 | } | |
310 | ||
bdedbb7b | 311 | static void ext4_es_free_extent(struct inode *inode, struct extent_status *es) |
654598be | 312 | { |
74cd15cd ZL |
313 | /* Decrease the lru counter when this es is not delayed */ |
314 | if (!ext4_es_is_delayed(es)) { | |
315 | BUG_ON(EXT4_I(inode)->i_es_lru_nr == 0); | |
316 | EXT4_I(inode)->i_es_lru_nr--; | |
317 | } | |
318 | ||
654598be ZL |
319 | kmem_cache_free(ext4_es_cachep, es); |
320 | } | |
321 | ||
06b0c886 ZL |
322 | /* |
323 | * Check whether or not two extents can be merged | |
324 | * Condition: | |
325 | * - logical block number is contiguous | |
fdc0212e ZL |
326 | * - physical block number is contiguous |
327 | * - status is equal | |
06b0c886 ZL |
328 | */ |
329 | static int ext4_es_can_be_merged(struct extent_status *es1, | |
330 | struct extent_status *es2) | |
331 | { | |
332 | if (es1->es_lblk + es1->es_len != es2->es_lblk) | |
333 | return 0; | |
334 | ||
fdc0212e ZL |
335 | if (ext4_es_status(es1) != ext4_es_status(es2)) |
336 | return 0; | |
337 | ||
338 | if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) && | |
339 | (ext4_es_pblock(es1) + es1->es_len != ext4_es_pblock(es2))) | |
340 | return 0; | |
341 | ||
06b0c886 ZL |
342 | return 1; |
343 | } | |
344 | ||
654598be | 345 | static struct extent_status * |
bdedbb7b | 346 | ext4_es_try_to_merge_left(struct inode *inode, struct extent_status *es) |
654598be | 347 | { |
bdedbb7b | 348 | struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; |
654598be ZL |
349 | struct extent_status *es1; |
350 | struct rb_node *node; | |
351 | ||
352 | node = rb_prev(&es->rb_node); | |
353 | if (!node) | |
354 | return es; | |
355 | ||
356 | es1 = rb_entry(node, struct extent_status, rb_node); | |
06b0c886 ZL |
357 | if (ext4_es_can_be_merged(es1, es)) { |
358 | es1->es_len += es->es_len; | |
654598be | 359 | rb_erase(&es->rb_node, &tree->root); |
bdedbb7b | 360 | ext4_es_free_extent(inode, es); |
654598be ZL |
361 | es = es1; |
362 | } | |
363 | ||
364 | return es; | |
365 | } | |
366 | ||
367 | static struct extent_status * | |
bdedbb7b | 368 | ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es) |
654598be | 369 | { |
bdedbb7b | 370 | struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; |
654598be ZL |
371 | struct extent_status *es1; |
372 | struct rb_node *node; | |
373 | ||
374 | node = rb_next(&es->rb_node); | |
375 | if (!node) | |
376 | return es; | |
377 | ||
378 | es1 = rb_entry(node, struct extent_status, rb_node); | |
06b0c886 ZL |
379 | if (ext4_es_can_be_merged(es, es1)) { |
380 | es->es_len += es1->es_len; | |
654598be | 381 | rb_erase(node, &tree->root); |
bdedbb7b | 382 | ext4_es_free_extent(inode, es1); |
654598be ZL |
383 | } |
384 | ||
385 | return es; | |
386 | } | |
387 | ||
bdedbb7b | 388 | static int __es_insert_extent(struct inode *inode, struct extent_status *newes) |
654598be | 389 | { |
bdedbb7b | 390 | struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; |
654598be ZL |
391 | struct rb_node **p = &tree->root.rb_node; |
392 | struct rb_node *parent = NULL; | |
393 | struct extent_status *es; | |
654598be ZL |
394 | |
395 | while (*p) { | |
396 | parent = *p; | |
397 | es = rb_entry(parent, struct extent_status, rb_node); | |
398 | ||
06b0c886 ZL |
399 | if (newes->es_lblk < es->es_lblk) { |
400 | if (ext4_es_can_be_merged(newes, es)) { | |
401 | /* | |
402 | * Here we can modify es_lblk directly | |
403 | * because it isn't overlapped. | |
404 | */ | |
405 | es->es_lblk = newes->es_lblk; | |
406 | es->es_len += newes->es_len; | |
fdc0212e ZL |
407 | if (ext4_es_is_written(es) || |
408 | ext4_es_is_unwritten(es)) | |
409 | ext4_es_store_pblock(es, | |
410 | newes->es_pblk); | |
bdedbb7b | 411 | es = ext4_es_try_to_merge_left(inode, es); |
654598be ZL |
412 | goto out; |
413 | } | |
414 | p = &(*p)->rb_left; | |
06b0c886 ZL |
415 | } else if (newes->es_lblk > ext4_es_end(es)) { |
416 | if (ext4_es_can_be_merged(es, newes)) { | |
417 | es->es_len += newes->es_len; | |
bdedbb7b | 418 | es = ext4_es_try_to_merge_right(inode, es); |
654598be ZL |
419 | goto out; |
420 | } | |
421 | p = &(*p)->rb_right; | |
422 | } else { | |
06b0c886 ZL |
423 | BUG_ON(1); |
424 | return -EINVAL; | |
654598be ZL |
425 | } |
426 | } | |
427 | ||
bdedbb7b | 428 | es = ext4_es_alloc_extent(inode, newes->es_lblk, newes->es_len, |
fdc0212e | 429 | newes->es_pblk); |
654598be ZL |
430 | if (!es) |
431 | return -ENOMEM; | |
432 | rb_link_node(&es->rb_node, parent, p); | |
433 | rb_insert_color(&es->rb_node, &tree->root); | |
434 | ||
435 | out: | |
436 | tree->cache_es = es; | |
437 | return 0; | |
438 | } | |
439 | ||
440 | /* | |
06b0c886 | 441 | * ext4_es_insert_extent() adds a space to a extent status tree. |
654598be ZL |
442 | * |
443 | * ext4_es_insert_extent is called by ext4_da_write_begin and | |
444 | * ext4_es_remove_extent. | |
445 | * | |
446 | * Return 0 on success, error code on failure. | |
447 | */ | |
06b0c886 | 448 | int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk, |
fdc0212e ZL |
449 | ext4_lblk_t len, ext4_fsblk_t pblk, |
450 | unsigned long long status) | |
654598be | 451 | { |
06b0c886 ZL |
452 | struct extent_status newes; |
453 | ext4_lblk_t end = lblk + len - 1; | |
654598be ZL |
454 | int err = 0; |
455 | ||
fdc0212e ZL |
456 | es_debug("add [%u/%u) %llu %llx to extent status tree of inode %lu\n", |
457 | lblk, len, pblk, status, inode->i_ino); | |
06b0c886 | 458 | |
d4381472 EG |
459 | if (!len) |
460 | return 0; | |
461 | ||
06b0c886 ZL |
462 | BUG_ON(end < lblk); |
463 | ||
464 | newes.es_lblk = lblk; | |
465 | newes.es_len = len; | |
fdc0212e ZL |
466 | ext4_es_store_pblock(&newes, pblk); |
467 | ext4_es_store_status(&newes, status); | |
468 | trace_ext4_es_insert_extent(inode, &newes); | |
654598be ZL |
469 | |
470 | write_lock(&EXT4_I(inode)->i_es_lock); | |
bdedbb7b | 471 | err = __es_remove_extent(inode, lblk, end); |
06b0c886 ZL |
472 | if (err != 0) |
473 | goto error; | |
bdedbb7b | 474 | err = __es_insert_extent(inode, &newes); |
06b0c886 ZL |
475 | |
476 | error: | |
654598be ZL |
477 | write_unlock(&EXT4_I(inode)->i_es_lock); |
478 | ||
74cd15cd | 479 | ext4_es_lru_add(inode); |
654598be ZL |
480 | ext4_es_print_tree(inode); |
481 | ||
482 | return err; | |
483 | } | |
484 | ||
d100eef2 ZL |
485 | /* |
486 | * ext4_es_lookup_extent() looks up an extent in extent status tree. | |
487 | * | |
488 | * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks. | |
489 | * | |
490 | * Return: 1 on found, 0 on not | |
491 | */ | |
492 | int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk, | |
493 | struct extent_status *es) | |
494 | { | |
495 | struct ext4_es_tree *tree; | |
496 | struct extent_status *es1 = NULL; | |
497 | struct rb_node *node; | |
498 | int found = 0; | |
499 | ||
500 | trace_ext4_es_lookup_extent_enter(inode, lblk); | |
501 | es_debug("lookup extent in block %u\n", lblk); | |
502 | ||
503 | tree = &EXT4_I(inode)->i_es_tree; | |
504 | read_lock(&EXT4_I(inode)->i_es_lock); | |
505 | ||
506 | /* find extent in cache firstly */ | |
507 | es->es_lblk = es->es_len = es->es_pblk = 0; | |
508 | if (tree->cache_es) { | |
509 | es1 = tree->cache_es; | |
510 | if (in_range(lblk, es1->es_lblk, es1->es_len)) { | |
511 | es_debug("%u cached by [%u/%u)\n", | |
512 | lblk, es1->es_lblk, es1->es_len); | |
513 | found = 1; | |
514 | goto out; | |
515 | } | |
516 | } | |
517 | ||
518 | node = tree->root.rb_node; | |
519 | while (node) { | |
520 | es1 = rb_entry(node, struct extent_status, rb_node); | |
521 | if (lblk < es1->es_lblk) | |
522 | node = node->rb_left; | |
523 | else if (lblk > ext4_es_end(es1)) | |
524 | node = node->rb_right; | |
525 | else { | |
526 | found = 1; | |
527 | break; | |
528 | } | |
529 | } | |
530 | ||
531 | out: | |
532 | if (found) { | |
533 | BUG_ON(!es1); | |
534 | es->es_lblk = es1->es_lblk; | |
535 | es->es_len = es1->es_len; | |
536 | es->es_pblk = es1->es_pblk; | |
537 | } | |
538 | ||
539 | read_unlock(&EXT4_I(inode)->i_es_lock); | |
540 | ||
74cd15cd | 541 | ext4_es_lru_add(inode); |
d100eef2 ZL |
542 | trace_ext4_es_lookup_extent_exit(inode, es, found); |
543 | return found; | |
544 | } | |
545 | ||
bdedbb7b ZL |
546 | static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk, |
547 | ext4_lblk_t end) | |
654598be | 548 | { |
bdedbb7b | 549 | struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree; |
654598be | 550 | struct rb_node *node; |
654598be ZL |
551 | struct extent_status *es; |
552 | struct extent_status orig_es; | |
06b0c886 | 553 | ext4_lblk_t len1, len2; |
fdc0212e | 554 | ext4_fsblk_t block; |
654598be ZL |
555 | int err = 0; |
556 | ||
06b0c886 | 557 | es = __es_tree_search(&tree->root, lblk); |
654598be ZL |
558 | if (!es) |
559 | goto out; | |
06b0c886 | 560 | if (es->es_lblk > end) |
654598be ZL |
561 | goto out; |
562 | ||
563 | /* Simply invalidate cache_es. */ | |
564 | tree->cache_es = NULL; | |
565 | ||
06b0c886 ZL |
566 | orig_es.es_lblk = es->es_lblk; |
567 | orig_es.es_len = es->es_len; | |
fdc0212e ZL |
568 | orig_es.es_pblk = es->es_pblk; |
569 | ||
06b0c886 ZL |
570 | len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0; |
571 | len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0; | |
654598be | 572 | if (len1 > 0) |
06b0c886 | 573 | es->es_len = len1; |
654598be ZL |
574 | if (len2 > 0) { |
575 | if (len1 > 0) { | |
06b0c886 ZL |
576 | struct extent_status newes; |
577 | ||
578 | newes.es_lblk = end + 1; | |
579 | newes.es_len = len2; | |
fdc0212e ZL |
580 | if (ext4_es_is_written(&orig_es) || |
581 | ext4_es_is_unwritten(&orig_es)) { | |
582 | block = ext4_es_pblock(&orig_es) + | |
583 | orig_es.es_len - len2; | |
584 | ext4_es_store_pblock(&newes, block); | |
585 | } | |
586 | ext4_es_store_status(&newes, ext4_es_status(&orig_es)); | |
bdedbb7b | 587 | err = __es_insert_extent(inode, &newes); |
654598be | 588 | if (err) { |
06b0c886 ZL |
589 | es->es_lblk = orig_es.es_lblk; |
590 | es->es_len = orig_es.es_len; | |
654598be ZL |
591 | goto out; |
592 | } | |
593 | } else { | |
06b0c886 ZL |
594 | es->es_lblk = end + 1; |
595 | es->es_len = len2; | |
fdc0212e ZL |
596 | if (ext4_es_is_written(es) || |
597 | ext4_es_is_unwritten(es)) { | |
598 | block = orig_es.es_pblk + orig_es.es_len - len2; | |
599 | ext4_es_store_pblock(es, block); | |
600 | } | |
654598be ZL |
601 | } |
602 | goto out; | |
603 | } | |
604 | ||
605 | if (len1 > 0) { | |
606 | node = rb_next(&es->rb_node); | |
607 | if (node) | |
608 | es = rb_entry(node, struct extent_status, rb_node); | |
609 | else | |
610 | es = NULL; | |
611 | } | |
612 | ||
06b0c886 | 613 | while (es && ext4_es_end(es) <= end) { |
654598be ZL |
614 | node = rb_next(&es->rb_node); |
615 | rb_erase(&es->rb_node, &tree->root); | |
bdedbb7b | 616 | ext4_es_free_extent(inode, es); |
654598be ZL |
617 | if (!node) { |
618 | es = NULL; | |
619 | break; | |
620 | } | |
621 | es = rb_entry(node, struct extent_status, rb_node); | |
622 | } | |
623 | ||
06b0c886 | 624 | if (es && es->es_lblk < end + 1) { |
fdc0212e ZL |
625 | ext4_lblk_t orig_len = es->es_len; |
626 | ||
06b0c886 ZL |
627 | len1 = ext4_es_end(es) - end; |
628 | es->es_lblk = end + 1; | |
629 | es->es_len = len1; | |
fdc0212e ZL |
630 | if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) { |
631 | block = es->es_pblk + orig_len - len1; | |
632 | ext4_es_store_pblock(es, block); | |
633 | } | |
654598be ZL |
634 | } |
635 | ||
636 | out: | |
06b0c886 ZL |
637 | return err; |
638 | } | |
639 | ||
640 | /* | |
641 | * ext4_es_remove_extent() removes a space from a extent status tree. | |
642 | * | |
643 | * Return 0 on success, error code on failure. | |
644 | */ | |
645 | int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, | |
646 | ext4_lblk_t len) | |
647 | { | |
06b0c886 ZL |
648 | ext4_lblk_t end; |
649 | int err = 0; | |
650 | ||
651 | trace_ext4_es_remove_extent(inode, lblk, len); | |
652 | es_debug("remove [%u/%u) from extent status tree of inode %lu\n", | |
653 | lblk, len, inode->i_ino); | |
654 | ||
d4381472 EG |
655 | if (!len) |
656 | return err; | |
657 | ||
06b0c886 ZL |
658 | end = lblk + len - 1; |
659 | BUG_ON(end < lblk); | |
660 | ||
06b0c886 | 661 | write_lock(&EXT4_I(inode)->i_es_lock); |
bdedbb7b | 662 | err = __es_remove_extent(inode, lblk, end); |
654598be ZL |
663 | write_unlock(&EXT4_I(inode)->i_es_lock); |
664 | ext4_es_print_tree(inode); | |
665 | return err; | |
666 | } | |
74cd15cd ZL |
667 | |
668 | static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc) | |
669 | { | |
670 | struct ext4_sb_info *sbi = container_of(shrink, | |
671 | struct ext4_sb_info, s_es_shrinker); | |
672 | struct ext4_inode_info *ei; | |
673 | struct list_head *cur, *tmp, scanned; | |
674 | int nr_to_scan = sc->nr_to_scan; | |
675 | int ret, nr_shrunk = 0; | |
676 | ||
677 | trace_ext4_es_shrink_enter(sbi->s_sb, nr_to_scan); | |
678 | ||
679 | if (!nr_to_scan) | |
680 | return ext4_es_reclaim_extents_count(sbi->s_sb); | |
681 | ||
682 | INIT_LIST_HEAD(&scanned); | |
683 | ||
684 | spin_lock(&sbi->s_es_lru_lock); | |
685 | list_for_each_safe(cur, tmp, &sbi->s_es_lru) { | |
686 | list_move_tail(cur, &scanned); | |
687 | ||
688 | ei = list_entry(cur, struct ext4_inode_info, i_es_lru); | |
689 | ||
690 | read_lock(&ei->i_es_lock); | |
691 | if (ei->i_es_lru_nr == 0) { | |
692 | read_unlock(&ei->i_es_lock); | |
693 | continue; | |
694 | } | |
695 | read_unlock(&ei->i_es_lock); | |
696 | ||
697 | write_lock(&ei->i_es_lock); | |
698 | ret = __es_try_to_reclaim_extents(ei, nr_to_scan); | |
699 | write_unlock(&ei->i_es_lock); | |
700 | ||
701 | nr_shrunk += ret; | |
702 | nr_to_scan -= ret; | |
703 | if (nr_to_scan == 0) | |
704 | break; | |
705 | } | |
706 | list_splice_tail(&scanned, &sbi->s_es_lru); | |
707 | spin_unlock(&sbi->s_es_lru_lock); | |
708 | trace_ext4_es_shrink_exit(sbi->s_sb, nr_shrunk); | |
709 | ||
710 | return ext4_es_reclaim_extents_count(sbi->s_sb); | |
711 | } | |
712 | ||
713 | void ext4_es_register_shrinker(struct super_block *sb) | |
714 | { | |
715 | struct ext4_sb_info *sbi; | |
716 | ||
717 | sbi = EXT4_SB(sb); | |
718 | INIT_LIST_HEAD(&sbi->s_es_lru); | |
719 | spin_lock_init(&sbi->s_es_lru_lock); | |
720 | sbi->s_es_shrinker.shrink = ext4_es_shrink; | |
721 | sbi->s_es_shrinker.seeks = DEFAULT_SEEKS; | |
722 | register_shrinker(&sbi->s_es_shrinker); | |
723 | } | |
724 | ||
725 | void ext4_es_unregister_shrinker(struct super_block *sb) | |
726 | { | |
727 | unregister_shrinker(&EXT4_SB(sb)->s_es_shrinker); | |
728 | } | |
729 | ||
730 | void ext4_es_lru_add(struct inode *inode) | |
731 | { | |
732 | struct ext4_inode_info *ei = EXT4_I(inode); | |
733 | struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); | |
734 | ||
735 | spin_lock(&sbi->s_es_lru_lock); | |
736 | if (list_empty(&ei->i_es_lru)) | |
737 | list_add_tail(&ei->i_es_lru, &sbi->s_es_lru); | |
738 | else | |
739 | list_move_tail(&ei->i_es_lru, &sbi->s_es_lru); | |
740 | spin_unlock(&sbi->s_es_lru_lock); | |
741 | } | |
742 | ||
743 | void ext4_es_lru_del(struct inode *inode) | |
744 | { | |
745 | struct ext4_inode_info *ei = EXT4_I(inode); | |
746 | struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); | |
747 | ||
748 | spin_lock(&sbi->s_es_lru_lock); | |
749 | if (!list_empty(&ei->i_es_lru)) | |
750 | list_del_init(&ei->i_es_lru); | |
751 | spin_unlock(&sbi->s_es_lru_lock); | |
752 | } | |
753 | ||
754 | static int ext4_es_reclaim_extents_count(struct super_block *sb) | |
755 | { | |
756 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
757 | struct ext4_inode_info *ei; | |
758 | struct list_head *cur; | |
759 | int nr_cached = 0; | |
760 | ||
761 | spin_lock(&sbi->s_es_lru_lock); | |
762 | list_for_each(cur, &sbi->s_es_lru) { | |
763 | ei = list_entry(cur, struct ext4_inode_info, i_es_lru); | |
764 | read_lock(&ei->i_es_lock); | |
765 | nr_cached += ei->i_es_lru_nr; | |
766 | read_unlock(&ei->i_es_lock); | |
767 | } | |
768 | spin_unlock(&sbi->s_es_lru_lock); | |
769 | trace_ext4_es_reclaim_extents_count(sb, nr_cached); | |
770 | return nr_cached; | |
771 | } | |
772 | ||
773 | static int __es_try_to_reclaim_extents(struct ext4_inode_info *ei, | |
774 | int nr_to_scan) | |
775 | { | |
776 | struct inode *inode = &ei->vfs_inode; | |
777 | struct ext4_es_tree *tree = &ei->i_es_tree; | |
778 | struct rb_node *node; | |
779 | struct extent_status *es; | |
780 | int nr_shrunk = 0; | |
781 | ||
782 | if (ei->i_es_lru_nr == 0) | |
783 | return 0; | |
784 | ||
785 | node = rb_first(&tree->root); | |
786 | while (node != NULL) { | |
787 | es = rb_entry(node, struct extent_status, rb_node); | |
788 | node = rb_next(&es->rb_node); | |
789 | /* | |
790 | * We can't reclaim delayed extent from status tree because | |
791 | * fiemap, bigallic, and seek_data/hole need to use it. | |
792 | */ | |
793 | if (!ext4_es_is_delayed(es)) { | |
794 | rb_erase(&es->rb_node, &tree->root); | |
795 | ext4_es_free_extent(inode, es); | |
796 | nr_shrunk++; | |
797 | if (--nr_to_scan == 0) | |
798 | break; | |
799 | } | |
800 | } | |
801 | tree->cache_es = NULL; | |
802 | return nr_shrunk; | |
803 | } |