Root/
1 | /* |
2 | * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README |
3 | */ |
4 | |
5 | /** |
6 | ** old_item_num |
7 | ** old_entry_num |
8 | ** set_entry_sizes |
9 | ** create_virtual_node |
10 | ** check_left |
11 | ** check_right |
12 | ** directory_part_size |
13 | ** get_num_ver |
14 | ** set_parameters |
15 | ** is_leaf_removable |
16 | ** are_leaves_removable |
17 | ** get_empty_nodes |
18 | ** get_lfree |
19 | ** get_rfree |
20 | ** is_left_neighbor_in_cache |
21 | ** decrement_key |
22 | ** get_far_parent |
23 | ** get_parents |
24 | ** can_node_be_removed |
25 | ** ip_check_balance |
26 | ** dc_check_balance_internal |
27 | ** dc_check_balance_leaf |
28 | ** dc_check_balance |
29 | ** check_balance |
30 | ** get_direct_parent |
31 | ** get_neighbors |
32 | ** fix_nodes |
33 | ** |
34 | ** |
35 | **/ |
36 | |
37 | #include <linux/time.h> |
38 | #include <linux/slab.h> |
39 | #include <linux/string.h> |
40 | #include <linux/reiserfs_fs.h> |
41 | #include <linux/buffer_head.h> |
42 | |
43 | /* To make any changes in the tree we find a node, that contains item |
44 | to be changed/deleted or position in the node we insert a new item |
45 | to. We call this node S. To do balancing we need to decide what we |
46 | will shift to left/right neighbor, or to a new node, where new item |
47 | will be etc. To make this analysis simpler we build virtual |
48 | node. Virtual node is an array of items, that will replace items of |
49 | node S. (For instance if we are going to delete an item, virtual |
50 | node does not contain it). Virtual node keeps information about |
51 | item sizes and types, mergeability of first and last items, sizes |
52 | of all entries in directory item. We use this array of items when |
53 | calculating what we can shift to neighbors and how many nodes we |
54 | have to have if we do not any shiftings, if we shift to left/right |
55 | neighbor or to both. */ |
56 | |
57 | /* taking item number in virtual node, returns number of item, that it has in source buffer */ |
58 | static inline int old_item_num(int new_num, int affected_item_num, int mode) |
59 | { |
60 | if (mode == M_PASTE || mode == M_CUT || new_num < affected_item_num) |
61 | return new_num; |
62 | |
63 | if (mode == M_INSERT) { |
64 | |
65 | RFALSE(new_num == 0, |
66 | "vs-8005: for INSERT mode and item number of inserted item"); |
67 | |
68 | return new_num - 1; |
69 | } |
70 | |
71 | RFALSE(mode != M_DELETE, |
72 | "vs-8010: old_item_num: mode must be M_DELETE (mode = \'%c\'", |
73 | mode); |
74 | /* delete mode */ |
75 | return new_num + 1; |
76 | } |
77 | |
78 | static void create_virtual_node(struct tree_balance *tb, int h) |
79 | { |
80 | struct item_head *ih; |
81 | struct virtual_node *vn = tb->tb_vn; |
82 | int new_num; |
83 | struct buffer_head *Sh; /* this comes from tb->S[h] */ |
84 | |
85 | Sh = PATH_H_PBUFFER(tb->tb_path, h); |
86 | |
87 | /* size of changed node */ |
88 | vn->vn_size = |
89 | MAX_CHILD_SIZE(Sh) - B_FREE_SPACE(Sh) + tb->insert_size[h]; |
90 | |
91 | /* for internal nodes array if virtual items is not created */ |
92 | if (h) { |
93 | vn->vn_nr_item = (vn->vn_size - DC_SIZE) / (DC_SIZE + KEY_SIZE); |
94 | return; |
95 | } |
96 | |
97 | /* number of items in virtual node */ |
98 | vn->vn_nr_item = |
99 | B_NR_ITEMS(Sh) + ((vn->vn_mode == M_INSERT) ? 1 : 0) - |
100 | ((vn->vn_mode == M_DELETE) ? 1 : 0); |
101 | |
102 | /* first virtual item */ |
103 | vn->vn_vi = (struct virtual_item *)(tb->tb_vn + 1); |
104 | memset(vn->vn_vi, 0, vn->vn_nr_item * sizeof(struct virtual_item)); |
105 | vn->vn_free_ptr += vn->vn_nr_item * sizeof(struct virtual_item); |
106 | |
107 | /* first item in the node */ |
108 | ih = B_N_PITEM_HEAD(Sh, 0); |
109 | |
110 | /* define the mergeability for 0-th item (if it is not being deleted) */ |
111 | if (op_is_left_mergeable(&(ih->ih_key), Sh->b_size) |
112 | && (vn->vn_mode != M_DELETE || vn->vn_affected_item_num)) |
113 | vn->vn_vi[0].vi_type |= VI_TYPE_LEFT_MERGEABLE; |
114 | |
115 | /* go through all items those remain in the virtual node (except for the new (inserted) one) */ |
116 | for (new_num = 0; new_num < vn->vn_nr_item; new_num++) { |
117 | int j; |
118 | struct virtual_item *vi = vn->vn_vi + new_num; |
119 | int is_affected = |
120 | ((new_num != vn->vn_affected_item_num) ? 0 : 1); |
121 | |
122 | if (is_affected && vn->vn_mode == M_INSERT) |
123 | continue; |
124 | |
125 | /* get item number in source node */ |
126 | j = old_item_num(new_num, vn->vn_affected_item_num, |
127 | vn->vn_mode); |
128 | |
129 | vi->vi_item_len += ih_item_len(ih + j) + IH_SIZE; |
130 | vi->vi_ih = ih + j; |
131 | vi->vi_item = B_I_PITEM(Sh, ih + j); |
132 | vi->vi_uarea = vn->vn_free_ptr; |
133 | |
134 | // FIXME: there is no check, that item operation did not |
135 | // consume too much memory |
136 | vn->vn_free_ptr += |
137 | op_create_vi(vn, vi, is_affected, tb->insert_size[0]); |
138 | if (tb->vn_buf + tb->vn_buf_size < vn->vn_free_ptr) |
139 | reiserfs_panic(tb->tb_sb, "vs-8030", |
140 | "virtual node space consumed"); |
141 | |
142 | if (!is_affected) |
143 | /* this is not being changed */ |
144 | continue; |
145 | |
146 | if (vn->vn_mode == M_PASTE || vn->vn_mode == M_CUT) { |
147 | vn->vn_vi[new_num].vi_item_len += tb->insert_size[0]; |
148 | vi->vi_new_data = vn->vn_data; // pointer to data which is going to be pasted |
149 | } |
150 | } |
151 | |
152 | /* virtual inserted item is not defined yet */ |
153 | if (vn->vn_mode == M_INSERT) { |
154 | struct virtual_item *vi = vn->vn_vi + vn->vn_affected_item_num; |
155 | |
156 | RFALSE(vn->vn_ins_ih == NULL, |
157 | "vs-8040: item header of inserted item is not specified"); |
158 | vi->vi_item_len = tb->insert_size[0]; |
159 | vi->vi_ih = vn->vn_ins_ih; |
160 | vi->vi_item = vn->vn_data; |
161 | vi->vi_uarea = vn->vn_free_ptr; |
162 | |
163 | op_create_vi(vn, vi, 0 /*not pasted or cut */ , |
164 | tb->insert_size[0]); |
165 | } |
166 | |
167 | /* set right merge flag we take right delimiting key and check whether it is a mergeable item */ |
168 | if (tb->CFR[0]) { |
169 | struct reiserfs_key *key; |
170 | |
171 | key = B_N_PDELIM_KEY(tb->CFR[0], tb->rkey[0]); |
172 | if (op_is_left_mergeable(key, Sh->b_size) |
173 | && (vn->vn_mode != M_DELETE |
174 | || vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) |
175 | vn->vn_vi[vn->vn_nr_item - 1].vi_type |= |
176 | VI_TYPE_RIGHT_MERGEABLE; |
177 | |
178 | #ifdef CONFIG_REISERFS_CHECK |
179 | if (op_is_left_mergeable(key, Sh->b_size) && |
180 | !(vn->vn_mode != M_DELETE |
181 | || vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) { |
182 | /* we delete last item and it could be merged with right neighbor's first item */ |
183 | if (! |
184 | (B_NR_ITEMS(Sh) == 1 |
185 | && is_direntry_le_ih(B_N_PITEM_HEAD(Sh, 0)) |
186 | && I_ENTRY_COUNT(B_N_PITEM_HEAD(Sh, 0)) == 1)) { |
187 | /* node contains more than 1 item, or item is not directory item, or this item contains more than 1 entry */ |
188 | print_block(Sh, 0, -1, -1); |
189 | reiserfs_panic(tb->tb_sb, "vs-8045", |
190 | "rdkey %k, affected item==%d " |
191 | "(mode==%c) Must be %c", |
192 | key, vn->vn_affected_item_num, |
193 | vn->vn_mode, M_DELETE); |
194 | } |
195 | } |
196 | #endif |
197 | |
198 | } |
199 | } |
200 | |
201 | /* using virtual node check, how many items can be shifted to left |
202 | neighbor */ |
203 | static void check_left(struct tree_balance *tb, int h, int cur_free) |
204 | { |
205 | int i; |
206 | struct virtual_node *vn = tb->tb_vn; |
207 | struct virtual_item *vi; |
208 | int d_size, ih_size; |
209 | |
210 | RFALSE(cur_free < 0, "vs-8050: cur_free (%d) < 0", cur_free); |
211 | |
212 | /* internal level */ |
213 | if (h > 0) { |
214 | tb->lnum[h] = cur_free / (DC_SIZE + KEY_SIZE); |
215 | return; |
216 | } |
217 | |
218 | /* leaf level */ |
219 | |
220 | if (!cur_free || !vn->vn_nr_item) { |
221 | /* no free space or nothing to move */ |
222 | tb->lnum[h] = 0; |
223 | tb->lbytes = -1; |
224 | return; |
225 | } |
226 | |
227 | RFALSE(!PATH_H_PPARENT(tb->tb_path, 0), |
228 | "vs-8055: parent does not exist or invalid"); |
229 | |
230 | vi = vn->vn_vi; |
231 | if ((unsigned int)cur_free >= |
232 | (vn->vn_size - |
233 | ((vi->vi_type & VI_TYPE_LEFT_MERGEABLE) ? IH_SIZE : 0))) { |
234 | /* all contents of S[0] fits into L[0] */ |
235 | |
236 | RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE, |
237 | "vs-8055: invalid mode or balance condition failed"); |
238 | |
239 | tb->lnum[0] = vn->vn_nr_item; |
240 | tb->lbytes = -1; |
241 | return; |
242 | } |
243 | |
244 | d_size = 0, ih_size = IH_SIZE; |
245 | |
246 | /* first item may be merge with last item in left neighbor */ |
247 | if (vi->vi_type & VI_TYPE_LEFT_MERGEABLE) |
248 | d_size = -((int)IH_SIZE), ih_size = 0; |
249 | |
250 | tb->lnum[0] = 0; |
251 | for (i = 0; i < vn->vn_nr_item; |
252 | i++, ih_size = IH_SIZE, d_size = 0, vi++) { |
253 | d_size += vi->vi_item_len; |
254 | if (cur_free >= d_size) { |
255 | /* the item can be shifted entirely */ |
256 | cur_free -= d_size; |
257 | tb->lnum[0]++; |
258 | continue; |
259 | } |
260 | |
261 | /* the item cannot be shifted entirely, try to split it */ |
262 | /* check whether L[0] can hold ih and at least one byte of the item body */ |
263 | if (cur_free <= ih_size) { |
264 | /* cannot shift even a part of the current item */ |
265 | tb->lbytes = -1; |
266 | return; |
267 | } |
268 | cur_free -= ih_size; |
269 | |
270 | tb->lbytes = op_check_left(vi, cur_free, 0, 0); |
271 | if (tb->lbytes != -1) |
272 | /* count partially shifted item */ |
273 | tb->lnum[0]++; |
274 | |
275 | break; |
276 | } |
277 | |
278 | return; |
279 | } |
280 | |
281 | /* using virtual node check, how many items can be shifted to right |
282 | neighbor */ |
283 | static void check_right(struct tree_balance *tb, int h, int cur_free) |
284 | { |
285 | int i; |
286 | struct virtual_node *vn = tb->tb_vn; |
287 | struct virtual_item *vi; |
288 | int d_size, ih_size; |
289 | |
290 | RFALSE(cur_free < 0, "vs-8070: cur_free < 0"); |
291 | |
292 | /* internal level */ |
293 | if (h > 0) { |
294 | tb->rnum[h] = cur_free / (DC_SIZE + KEY_SIZE); |
295 | return; |
296 | } |
297 | |
298 | /* leaf level */ |
299 | |
300 | if (!cur_free || !vn->vn_nr_item) { |
301 | /* no free space */ |
302 | tb->rnum[h] = 0; |
303 | tb->rbytes = -1; |
304 | return; |
305 | } |
306 | |
307 | RFALSE(!PATH_H_PPARENT(tb->tb_path, 0), |
308 | "vs-8075: parent does not exist or invalid"); |
309 | |
310 | vi = vn->vn_vi + vn->vn_nr_item - 1; |
311 | if ((unsigned int)cur_free >= |
312 | (vn->vn_size - |
313 | ((vi->vi_type & VI_TYPE_RIGHT_MERGEABLE) ? IH_SIZE : 0))) { |
314 | /* all contents of S[0] fits into R[0] */ |
315 | |
316 | RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE, |
317 | "vs-8080: invalid mode or balance condition failed"); |
318 | |
319 | tb->rnum[h] = vn->vn_nr_item; |
320 | tb->rbytes = -1; |
321 | return; |
322 | } |
323 | |
324 | d_size = 0, ih_size = IH_SIZE; |
325 | |
326 | /* last item may be merge with first item in right neighbor */ |
327 | if (vi->vi_type & VI_TYPE_RIGHT_MERGEABLE) |
328 | d_size = -(int)IH_SIZE, ih_size = 0; |
329 | |
330 | tb->rnum[0] = 0; |
331 | for (i = vn->vn_nr_item - 1; i >= 0; |
332 | i--, d_size = 0, ih_size = IH_SIZE, vi--) { |
333 | d_size += vi->vi_item_len; |
334 | if (cur_free >= d_size) { |
335 | /* the item can be shifted entirely */ |
336 | cur_free -= d_size; |
337 | tb->rnum[0]++; |
338 | continue; |
339 | } |
340 | |
341 | /* check whether R[0] can hold ih and at least one byte of the item body */ |
342 | if (cur_free <= ih_size) { /* cannot shift even a part of the current item */ |
343 | tb->rbytes = -1; |
344 | return; |
345 | } |
346 | |
347 | /* R[0] can hold the header of the item and at least one byte of its body */ |
348 | cur_free -= ih_size; /* cur_free is still > 0 */ |
349 | |
350 | tb->rbytes = op_check_right(vi, cur_free); |
351 | if (tb->rbytes != -1) |
352 | /* count partially shifted item */ |
353 | tb->rnum[0]++; |
354 | |
355 | break; |
356 | } |
357 | |
358 | return; |
359 | } |
360 | |
361 | /* |
362 | * from - number of items, which are shifted to left neighbor entirely |
363 | * to - number of item, which are shifted to right neighbor entirely |
364 | * from_bytes - number of bytes of boundary item (or directory entries) which are shifted to left neighbor |
365 | * to_bytes - number of bytes of boundary item (or directory entries) which are shifted to right neighbor */ |
366 | static int get_num_ver(int mode, struct tree_balance *tb, int h, |
367 | int from, int from_bytes, |
368 | int to, int to_bytes, short *snum012, int flow) |
369 | { |
370 | int i; |
371 | int cur_free; |
372 | // int bytes; |
373 | int units; |
374 | struct virtual_node *vn = tb->tb_vn; |
375 | // struct virtual_item * vi; |
376 | |
377 | int total_node_size, max_node_size, current_item_size; |
378 | int needed_nodes; |
379 | int start_item, /* position of item we start filling node from */ |
380 | end_item, /* position of item we finish filling node by */ |
381 | start_bytes, /* number of first bytes (entries for directory) of start_item-th item |
382 | we do not include into node that is being filled */ |
383 | end_bytes; /* number of last bytes (entries for directory) of end_item-th item |
384 | we do node include into node that is being filled */ |
385 | int split_item_positions[2]; /* these are positions in virtual item of |
386 | items, that are split between S[0] and |
387 | S1new and S1new and S2new */ |
388 | |
389 | split_item_positions[0] = -1; |
390 | split_item_positions[1] = -1; |
391 | |
392 | /* We only create additional nodes if we are in insert or paste mode |
393 | or we are in replace mode at the internal level. If h is 0 and |
394 | the mode is M_REPLACE then in fix_nodes we change the mode to |
395 | paste or insert before we get here in the code. */ |
396 | RFALSE(tb->insert_size[h] < 0 || (mode != M_INSERT && mode != M_PASTE), |
397 | "vs-8100: insert_size < 0 in overflow"); |
398 | |
399 | max_node_size = MAX_CHILD_SIZE(PATH_H_PBUFFER(tb->tb_path, h)); |
400 | |
401 | /* snum012 [0-2] - number of items, that lay |
402 | to S[0], first new node and second new node */ |
403 | snum012[3] = -1; /* s1bytes */ |
404 | snum012[4] = -1; /* s2bytes */ |
405 | |
406 | /* internal level */ |
407 | if (h > 0) { |
408 | i = ((to - from) * (KEY_SIZE + DC_SIZE) + DC_SIZE); |
409 | if (i == max_node_size) |
410 | return 1; |
411 | return (i / max_node_size + 1); |
412 | } |
413 | |
414 | /* leaf level */ |
415 | needed_nodes = 1; |
416 | total_node_size = 0; |
417 | cur_free = max_node_size; |
418 | |
419 | // start from 'from'-th item |
420 | start_item = from; |
421 | // skip its first 'start_bytes' units |
422 | start_bytes = ((from_bytes != -1) ? from_bytes : 0); |
423 | |
424 | // last included item is the 'end_item'-th one |
425 | end_item = vn->vn_nr_item - to - 1; |
426 | // do not count last 'end_bytes' units of 'end_item'-th item |
427 | end_bytes = (to_bytes != -1) ? to_bytes : 0; |
428 | |
429 | /* go through all item beginning from the start_item-th item and ending by |
430 | the end_item-th item. Do not count first 'start_bytes' units of |
431 | 'start_item'-th item and last 'end_bytes' of 'end_item'-th item */ |
432 | |
433 | for (i = start_item; i <= end_item; i++) { |
434 | struct virtual_item *vi = vn->vn_vi + i; |
435 | int skip_from_end = ((i == end_item) ? end_bytes : 0); |
436 | |
437 | RFALSE(needed_nodes > 3, "vs-8105: too many nodes are needed"); |
438 | |
439 | /* get size of current item */ |
440 | current_item_size = vi->vi_item_len; |
441 | |
442 | /* do not take in calculation head part (from_bytes) of from-th item */ |
443 | current_item_size -= |
444 | op_part_size(vi, 0 /*from start */ , start_bytes); |
445 | |
446 | /* do not take in calculation tail part of last item */ |
447 | current_item_size -= |
448 | op_part_size(vi, 1 /*from end */ , skip_from_end); |
449 | |
450 | /* if item fits into current node entierly */ |
451 | if (total_node_size + current_item_size <= max_node_size) { |
452 | snum012[needed_nodes - 1]++; |
453 | total_node_size += current_item_size; |
454 | start_bytes = 0; |
455 | continue; |
456 | } |
457 | |
458 | if (current_item_size > max_node_size) { |
459 | /* virtual item length is longer, than max size of item in |
460 | a node. It is impossible for direct item */ |
461 | RFALSE(is_direct_le_ih(vi->vi_ih), |
462 | "vs-8110: " |
463 | "direct item length is %d. It can not be longer than %d", |
464 | current_item_size, max_node_size); |
465 | /* we will try to split it */ |
466 | flow = 1; |
467 | } |
468 | |
469 | if (!flow) { |
470 | /* as we do not split items, take new node and continue */ |
471 | needed_nodes++; |
472 | i--; |
473 | total_node_size = 0; |
474 | continue; |
475 | } |
476 | // calculate number of item units which fit into node being |
477 | // filled |
478 | { |
479 | int free_space; |
480 | |
481 | free_space = max_node_size - total_node_size - IH_SIZE; |
482 | units = |
483 | op_check_left(vi, free_space, start_bytes, |
484 | skip_from_end); |
485 | if (units == -1) { |
486 | /* nothing fits into current node, take new node and continue */ |
487 | needed_nodes++, i--, total_node_size = 0; |
488 | continue; |
489 | } |
490 | } |
491 | |
492 | /* something fits into the current node */ |
493 | //if (snum012[3] != -1 || needed_nodes != 1) |
494 | // reiserfs_panic (tb->tb_sb, "vs-8115: get_num_ver: too many nodes required"); |
495 | //snum012[needed_nodes - 1 + 3] = op_unit_num (vi) - start_bytes - units; |
496 | start_bytes += units; |
497 | snum012[needed_nodes - 1 + 3] = units; |
498 | |
499 | if (needed_nodes > 2) |
500 | reiserfs_warning(tb->tb_sb, "vs-8111", |
501 | "split_item_position is out of range"); |
502 | snum012[needed_nodes - 1]++; |
503 | split_item_positions[needed_nodes - 1] = i; |
504 | needed_nodes++; |
505 | /* continue from the same item with start_bytes != -1 */ |
506 | start_item = i; |
507 | i--; |
508 | total_node_size = 0; |
509 | } |
510 | |
511 | // sum012[4] (if it is not -1) contains number of units of which |
512 | // are to be in S1new, snum012[3] - to be in S0. They are supposed |
513 | // to be S1bytes and S2bytes correspondingly, so recalculate |
514 | if (snum012[4] > 0) { |
515 | int split_item_num; |
516 | int bytes_to_r, bytes_to_l; |
517 | int bytes_to_S1new; |
518 | |
519 | split_item_num = split_item_positions[1]; |
520 | bytes_to_l = |
521 | ((from == split_item_num |
522 | && from_bytes != -1) ? from_bytes : 0); |
523 | bytes_to_r = |
524 | ((end_item == split_item_num |
525 | && end_bytes != -1) ? end_bytes : 0); |
526 | bytes_to_S1new = |
527 | ((split_item_positions[0] == |
528 | split_item_positions[1]) ? snum012[3] : 0); |
529 | |
530 | // s2bytes |
531 | snum012[4] = |
532 | op_unit_num(&vn->vn_vi[split_item_num]) - snum012[4] - |
533 | bytes_to_r - bytes_to_l - bytes_to_S1new; |
534 | |
535 | if (vn->vn_vi[split_item_num].vi_index != TYPE_DIRENTRY && |
536 | vn->vn_vi[split_item_num].vi_index != TYPE_INDIRECT) |
537 | reiserfs_warning(tb->tb_sb, "vs-8115", |
538 | "not directory or indirect item"); |
539 | } |
540 | |
541 | /* now we know S2bytes, calculate S1bytes */ |
542 | if (snum012[3] > 0) { |
543 | int split_item_num; |
544 | int bytes_to_r, bytes_to_l; |
545 | int bytes_to_S2new; |
546 | |
547 | split_item_num = split_item_positions[0]; |
548 | bytes_to_l = |
549 | ((from == split_item_num |
550 | && from_bytes != -1) ? from_bytes : 0); |
551 | bytes_to_r = |
552 | ((end_item == split_item_num |
553 | && end_bytes != -1) ? end_bytes : 0); |
554 | bytes_to_S2new = |
555 | ((split_item_positions[0] == split_item_positions[1] |
556 | && snum012[4] != -1) ? snum012[4] : 0); |
557 | |
558 | // s1bytes |
559 | snum012[3] = |
560 | op_unit_num(&vn->vn_vi[split_item_num]) - snum012[3] - |
561 | bytes_to_r - bytes_to_l - bytes_to_S2new; |
562 | } |
563 | |
564 | return needed_nodes; |
565 | } |
566 | |
567 | |
568 | /* Set parameters for balancing. |
569 | * Performs write of results of analysis of balancing into structure tb, |
570 | * where it will later be used by the functions that actually do the balancing. |
571 | * Parameters: |
572 | * tb tree_balance structure; |
573 | * h current level of the node; |
574 | * lnum number of items from S[h] that must be shifted to L[h]; |
575 | * rnum number of items from S[h] that must be shifted to R[h]; |
576 | * blk_num number of blocks that S[h] will be splitted into; |
577 | * s012 number of items that fall into splitted nodes. |
578 | * lbytes number of bytes which flow to the left neighbor from the item that is not |
579 | * not shifted entirely |
580 | * rbytes number of bytes which flow to the right neighbor from the item that is not |
581 | * not shifted entirely |
582 | * s1bytes number of bytes which flow to the first new node when S[0] splits (this number is contained in s012 array) |
583 | */ |
584 | |
585 | static void set_parameters(struct tree_balance *tb, int h, int lnum, |
586 | int rnum, int blk_num, short *s012, int lb, int rb) |
587 | { |
588 | |
589 | tb->lnum[h] = lnum; |
590 | tb->rnum[h] = rnum; |
591 | tb->blknum[h] = blk_num; |
592 | |
593 | if (h == 0) { /* only for leaf level */ |
594 | if (s012 != NULL) { |
595 | tb->s0num = *s012++, |
596 | tb->s1num = *s012++, tb->s2num = *s012++; |
597 | tb->s1bytes = *s012++; |
598 | tb->s2bytes = *s012; |
599 | } |
600 | tb->lbytes = lb; |
601 | tb->rbytes = rb; |
602 | } |
603 | PROC_INFO_ADD(tb->tb_sb, lnum[h], lnum); |
604 | PROC_INFO_ADD(tb->tb_sb, rnum[h], rnum); |
605 | |
606 | PROC_INFO_ADD(tb->tb_sb, lbytes[h], lb); |
607 | PROC_INFO_ADD(tb->tb_sb, rbytes[h], rb); |
608 | } |
609 | |
610 | /* check, does node disappear if we shift tb->lnum[0] items to left |
611 | neighbor and tb->rnum[0] to the right one. */ |
612 | static int is_leaf_removable(struct tree_balance *tb) |
613 | { |
614 | struct virtual_node *vn = tb->tb_vn; |
615 | int to_left, to_right; |
616 | int size; |
617 | int remain_items; |
618 | |
619 | /* number of items, that will be shifted to left (right) neighbor |
620 | entirely */ |
621 | to_left = tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0); |
622 | to_right = tb->rnum[0] - ((tb->rbytes != -1) ? 1 : 0); |
623 | remain_items = vn->vn_nr_item; |
624 | |
625 | /* how many items remain in S[0] after shiftings to neighbors */ |
626 | remain_items -= (to_left + to_right); |
627 | |
628 | if (remain_items < 1) { |
629 | /* all content of node can be shifted to neighbors */ |
630 | set_parameters(tb, 0, to_left, vn->vn_nr_item - to_left, 0, |
631 | NULL, -1, -1); |
632 | return 1; |
633 | } |
634 | |
635 | if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1) |
636 | /* S[0] is not removable */ |
637 | return 0; |
638 | |
639 | /* check, whether we can divide 1 remaining item between neighbors */ |
640 | |
641 | /* get size of remaining item (in item units) */ |
642 | size = op_unit_num(&(vn->vn_vi[to_left])); |
643 | |
644 | if (tb->lbytes + tb->rbytes >= size) { |
645 | set_parameters(tb, 0, to_left + 1, to_right + 1, 0, NULL, |
646 | tb->lbytes, -1); |
647 | return 1; |
648 | } |
649 | |
650 | return 0; |
651 | } |
652 | |
653 | /* check whether L, S, R can be joined in one node */ |
654 | static int are_leaves_removable(struct tree_balance *tb, int lfree, int rfree) |
655 | { |
656 | struct virtual_node *vn = tb->tb_vn; |
657 | int ih_size; |
658 | struct buffer_head *S0; |
659 | |
660 | S0 = PATH_H_PBUFFER(tb->tb_path, 0); |
661 | |
662 | ih_size = 0; |
663 | if (vn->vn_nr_item) { |
664 | if (vn->vn_vi[0].vi_type & VI_TYPE_LEFT_MERGEABLE) |
665 | ih_size += IH_SIZE; |
666 | |
667 | if (vn->vn_vi[vn->vn_nr_item - 1]. |
668 | vi_type & VI_TYPE_RIGHT_MERGEABLE) |
669 | ih_size += IH_SIZE; |
670 | } else { |
671 | /* there was only one item and it will be deleted */ |
672 | struct item_head *ih; |
673 | |
674 | RFALSE(B_NR_ITEMS(S0) != 1, |
675 | "vs-8125: item number must be 1: it is %d", |
676 | B_NR_ITEMS(S0)); |
677 | |
678 | ih = B_N_PITEM_HEAD(S0, 0); |
679 | if (tb->CFR[0] |
680 | && !comp_short_le_keys(&(ih->ih_key), |
681 | B_N_PDELIM_KEY(tb->CFR[0], |
682 | tb->rkey[0]))) |
683 | if (is_direntry_le_ih(ih)) { |
684 | /* Directory must be in correct state here: that is |
685 | somewhere at the left side should exist first directory |
686 | item. But the item being deleted can not be that first |
687 | one because its right neighbor is item of the same |
688 | directory. (But first item always gets deleted in last |
689 | turn). So, neighbors of deleted item can be merged, so |
690 | we can save ih_size */ |
691 | ih_size = IH_SIZE; |
692 | |
693 | /* we might check that left neighbor exists and is of the |
694 | same directory */ |
695 | RFALSE(le_ih_k_offset(ih) == DOT_OFFSET, |
696 | "vs-8130: first directory item can not be removed until directory is not empty"); |
697 | } |
698 | |
699 | } |
700 | |
701 | if (MAX_CHILD_SIZE(S0) + vn->vn_size <= rfree + lfree + ih_size) { |
702 | set_parameters(tb, 0, -1, -1, -1, NULL, -1, -1); |
703 | PROC_INFO_INC(tb->tb_sb, leaves_removable); |
704 | return 1; |
705 | } |
706 | return 0; |
707 | |
708 | } |
709 | |
710 | /* when we do not split item, lnum and rnum are numbers of entire items */ |
711 | #define SET_PAR_SHIFT_LEFT \ |
712 | if (h)\ |
713 | {\ |
714 | int to_l;\ |
715 | \ |
716 | to_l = (MAX_NR_KEY(Sh)+1 - lpar + vn->vn_nr_item + 1) / 2 -\ |
717 | (MAX_NR_KEY(Sh) + 1 - lpar);\ |
718 | \ |
719 | set_parameters (tb, h, to_l, 0, lnver, NULL, -1, -1);\ |
720 | }\ |
721 | else \ |
722 | {\ |
723 | if (lset==LEFT_SHIFT_FLOW)\ |
724 | set_parameters (tb, h, lpar, 0, lnver, snum012+lset,\ |
725 | tb->lbytes, -1);\ |
726 | else\ |
727 | set_parameters (tb, h, lpar - (tb->lbytes!=-1), 0, lnver, snum012+lset,\ |
728 | -1, -1);\ |
729 | } |
730 | |
731 | #define SET_PAR_SHIFT_RIGHT \ |
732 | if (h)\ |
733 | {\ |
734 | int to_r;\ |
735 | \ |
736 | to_r = (MAX_NR_KEY(Sh)+1 - rpar + vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - rpar);\ |
737 | \ |
738 | set_parameters (tb, h, 0, to_r, rnver, NULL, -1, -1);\ |
739 | }\ |
740 | else \ |
741 | {\ |
742 | if (rset==RIGHT_SHIFT_FLOW)\ |
743 | set_parameters (tb, h, 0, rpar, rnver, snum012+rset,\ |
744 | -1, tb->rbytes);\ |
745 | else\ |
746 | set_parameters (tb, h, 0, rpar - (tb->rbytes!=-1), rnver, snum012+rset,\ |
747 | -1, -1);\ |
748 | } |
749 | |
750 | static void free_buffers_in_tb(struct tree_balance *tb) |
751 | { |
752 | int i; |
753 | |
754 | pathrelse(tb->tb_path); |
755 | |
756 | for (i = 0; i < MAX_HEIGHT; i++) { |
757 | brelse(tb->L[i]); |
758 | brelse(tb->R[i]); |
759 | brelse(tb->FL[i]); |
760 | brelse(tb->FR[i]); |
761 | brelse(tb->CFL[i]); |
762 | brelse(tb->CFR[i]); |
763 | |
764 | tb->L[i] = NULL; |
765 | tb->R[i] = NULL; |
766 | tb->FL[i] = NULL; |
767 | tb->FR[i] = NULL; |
768 | tb->CFL[i] = NULL; |
769 | tb->CFR[i] = NULL; |
770 | } |
771 | } |
772 | |
773 | /* Get new buffers for storing new nodes that are created while balancing. |
774 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; |
775 | * CARRY_ON - schedule didn't occur while the function worked; |
776 | * NO_DISK_SPACE - no disk space. |
777 | */ |
778 | /* The function is NOT SCHEDULE-SAFE! */ |
779 | static int get_empty_nodes(struct tree_balance *tb, int h) |
780 | { |
781 | struct buffer_head *new_bh, |
782 | *Sh = PATH_H_PBUFFER(tb->tb_path, h); |
783 | b_blocknr_t *blocknr, blocknrs[MAX_AMOUNT_NEEDED] = { 0, }; |
784 | int counter, number_of_freeblk, amount_needed, /* number of needed empty blocks */ |
785 | retval = CARRY_ON; |
786 | struct super_block *sb = tb->tb_sb; |
787 | |
788 | /* number_of_freeblk is the number of empty blocks which have been |
789 | acquired for use by the balancing algorithm minus the number of |
790 | empty blocks used in the previous levels of the analysis, |
791 | number_of_freeblk = tb->cur_blknum can be non-zero if a schedule occurs |
792 | after empty blocks are acquired, and the balancing analysis is |
793 | then restarted, amount_needed is the number needed by this level |
794 | (h) of the balancing analysis. |
795 | |
796 | Note that for systems with many processes writing, it would be |
797 | more layout optimal to calculate the total number needed by all |
798 | levels and then to run reiserfs_new_blocks to get all of them at once. */ |
799 | |
800 | /* Initiate number_of_freeblk to the amount acquired prior to the restart of |
801 | the analysis or 0 if not restarted, then subtract the amount needed |
802 | by all of the levels of the tree below h. */ |
803 | /* blknum includes S[h], so we subtract 1 in this calculation */ |
804 | for (counter = 0, number_of_freeblk = tb->cur_blknum; |
805 | counter < h; counter++) |
806 | number_of_freeblk -= |
807 | (tb->blknum[counter]) ? (tb->blknum[counter] - |
808 | 1) : 0; |
809 | |
810 | /* Allocate missing empty blocks. */ |
811 | /* if Sh == 0 then we are getting a new root */ |
812 | amount_needed = (Sh) ? (tb->blknum[h] - 1) : 1; |
813 | /* Amount_needed = the amount that we need more than the amount that we have. */ |
814 | if (amount_needed > number_of_freeblk) |
815 | amount_needed -= number_of_freeblk; |
816 | else /* If we have enough already then there is nothing to do. */ |
817 | return CARRY_ON; |
818 | |
819 | /* No need to check quota - is not allocated for blocks used for formatted nodes */ |
820 | if (reiserfs_new_form_blocknrs(tb, blocknrs, |
821 | amount_needed) == NO_DISK_SPACE) |
822 | return NO_DISK_SPACE; |
823 | |
824 | /* for each blocknumber we just got, get a buffer and stick it on FEB */ |
825 | for (blocknr = blocknrs, counter = 0; |
826 | counter < amount_needed; blocknr++, counter++) { |
827 | |
828 | RFALSE(!*blocknr, |
829 | "PAP-8135: reiserfs_new_blocknrs failed when got new blocks"); |
830 | |
831 | new_bh = sb_getblk(sb, *blocknr); |
832 | RFALSE(buffer_dirty(new_bh) || |
833 | buffer_journaled(new_bh) || |
834 | buffer_journal_dirty(new_bh), |
835 | "PAP-8140: journaled or dirty buffer %b for the new block", |
836 | new_bh); |
837 | |
838 | /* Put empty buffers into the array. */ |
839 | RFALSE(tb->FEB[tb->cur_blknum], |
840 | "PAP-8141: busy slot for new buffer"); |
841 | |
842 | set_buffer_journal_new(new_bh); |
843 | tb->FEB[tb->cur_blknum++] = new_bh; |
844 | } |
845 | |
846 | if (retval == CARRY_ON && FILESYSTEM_CHANGED_TB(tb)) |
847 | retval = REPEAT_SEARCH; |
848 | |
849 | return retval; |
850 | } |
851 | |
852 | /* Get free space of the left neighbor, which is stored in the parent |
853 | * node of the left neighbor. */ |
854 | static int get_lfree(struct tree_balance *tb, int h) |
855 | { |
856 | struct buffer_head *l, *f; |
857 | int order; |
858 | |
859 | if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL || |
860 | (l = tb->FL[h]) == NULL) |
861 | return 0; |
862 | |
863 | if (f == l) |
864 | order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) - 1; |
865 | else { |
866 | order = B_NR_ITEMS(l); |
867 | f = l; |
868 | } |
869 | |
870 | return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order))); |
871 | } |
872 | |
873 | /* Get free space of the right neighbor, |
874 | * which is stored in the parent node of the right neighbor. |
875 | */ |
876 | static int get_rfree(struct tree_balance *tb, int h) |
877 | { |
878 | struct buffer_head *r, *f; |
879 | int order; |
880 | |
881 | if ((f = PATH_H_PPARENT(tb->tb_path, h)) == NULL || |
882 | (r = tb->FR[h]) == NULL) |
883 | return 0; |
884 | |
885 | if (f == r) |
886 | order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) + 1; |
887 | else { |
888 | order = 0; |
889 | f = r; |
890 | } |
891 | |
892 | return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order))); |
893 | |
894 | } |
895 | |
896 | /* Check whether left neighbor is in memory. */ |
897 | static int is_left_neighbor_in_cache(struct tree_balance *tb, int h) |
898 | { |
899 | struct buffer_head *father, *left; |
900 | struct super_block *sb = tb->tb_sb; |
901 | b_blocknr_t left_neighbor_blocknr; |
902 | int left_neighbor_position; |
903 | |
904 | /* Father of the left neighbor does not exist. */ |
905 | if (!tb->FL[h]) |
906 | return 0; |
907 | |
908 | /* Calculate father of the node to be balanced. */ |
909 | father = PATH_H_PBUFFER(tb->tb_path, h + 1); |
910 | |
911 | RFALSE(!father || |
912 | !B_IS_IN_TREE(father) || |
913 | !B_IS_IN_TREE(tb->FL[h]) || |
914 | !buffer_uptodate(father) || |
915 | !buffer_uptodate(tb->FL[h]), |
916 | "vs-8165: F[h] (%b) or FL[h] (%b) is invalid", |
917 | father, tb->FL[h]); |
918 | |
919 | /* Get position of the pointer to the left neighbor into the left father. */ |
920 | left_neighbor_position = (father == tb->FL[h]) ? |
921 | tb->lkey[h] : B_NR_ITEMS(tb->FL[h]); |
922 | /* Get left neighbor block number. */ |
923 | left_neighbor_blocknr = |
924 | B_N_CHILD_NUM(tb->FL[h], left_neighbor_position); |
925 | /* Look for the left neighbor in the cache. */ |
926 | if ((left = sb_find_get_block(sb, left_neighbor_blocknr))) { |
927 | |
928 | RFALSE(buffer_uptodate(left) && !B_IS_IN_TREE(left), |
929 | "vs-8170: left neighbor (%b %z) is not in the tree", |
930 | left, left); |
931 | put_bh(left); |
932 | return 1; |
933 | } |
934 | |
935 | return 0; |
936 | } |
937 | |
938 | #define LEFT_PARENTS 'l' |
939 | #define RIGHT_PARENTS 'r' |
940 | |
941 | static void decrement_key(struct cpu_key *key) |
942 | { |
943 | // call item specific function for this key |
944 | item_ops[cpu_key_k_type(key)]->decrement_key(key); |
945 | } |
946 | |
947 | /* Calculate far left/right parent of the left/right neighbor of the current node, that |
948 | * is calculate the left/right (FL[h]/FR[h]) neighbor of the parent F[h]. |
949 | * Calculate left/right common parent of the current node and L[h]/R[h]. |
950 | * Calculate left/right delimiting key position. |
951 | * Returns: PATH_INCORRECT - path in the tree is not correct; |
952 | SCHEDULE_OCCURRED - schedule occurred while the function worked; |
953 | * CARRY_ON - schedule didn't occur while the function worked; |
954 | */ |
955 | static int get_far_parent(struct tree_balance *tb, |
956 | int h, |
957 | struct buffer_head **pfather, |
958 | struct buffer_head **pcom_father, char c_lr_par) |
959 | { |
960 | struct buffer_head *parent; |
961 | INITIALIZE_PATH(s_path_to_neighbor_father); |
962 | struct treepath *path = tb->tb_path; |
963 | struct cpu_key s_lr_father_key; |
964 | int counter, |
965 | position = INT_MAX, |
966 | first_last_position = 0, |
967 | path_offset = PATH_H_PATH_OFFSET(path, h); |
968 | |
969 | /* Starting from F[h] go upwards in the tree, and look for the common |
970 | ancestor of F[h], and its neighbor l/r, that should be obtained. */ |
971 | |
972 | counter = path_offset; |
973 | |
974 | RFALSE(counter < FIRST_PATH_ELEMENT_OFFSET, |
975 | "PAP-8180: invalid path length"); |
976 | |
977 | for (; counter > FIRST_PATH_ELEMENT_OFFSET; counter--) { |
978 | /* Check whether parent of the current buffer in the path is really parent in the tree. */ |
979 | if (!B_IS_IN_TREE |
980 | (parent = PATH_OFFSET_PBUFFER(path, counter - 1))) |
981 | return REPEAT_SEARCH; |
982 | /* Check whether position in the parent is correct. */ |
983 | if ((position = |
984 | PATH_OFFSET_POSITION(path, |
985 | counter - 1)) > |
986 | B_NR_ITEMS(parent)) |
987 | return REPEAT_SEARCH; |
988 | /* Check whether parent at the path really points to the child. */ |
989 | if (B_N_CHILD_NUM(parent, position) != |
990 | PATH_OFFSET_PBUFFER(path, counter)->b_blocknr) |
991 | return REPEAT_SEARCH; |
992 | /* Return delimiting key if position in the parent is not equal to first/last one. */ |
993 | if (c_lr_par == RIGHT_PARENTS) |
994 | first_last_position = B_NR_ITEMS(parent); |
995 | if (position != first_last_position) { |
996 | *pcom_father = parent; |
997 | get_bh(*pcom_father); |
998 | /*(*pcom_father = parent)->b_count++; */ |
999 | break; |
1000 | } |
1001 | } |
1002 | |
1003 | /* if we are in the root of the tree, then there is no common father */ |
1004 | if (counter == FIRST_PATH_ELEMENT_OFFSET) { |
1005 | /* Check whether first buffer in the path is the root of the tree. */ |
1006 | if (PATH_OFFSET_PBUFFER |
1007 | (tb->tb_path, |
1008 | FIRST_PATH_ELEMENT_OFFSET)->b_blocknr == |
1009 | SB_ROOT_BLOCK(tb->tb_sb)) { |
1010 | *pfather = *pcom_father = NULL; |
1011 | return CARRY_ON; |
1012 | } |
1013 | return REPEAT_SEARCH; |
1014 | } |
1015 | |
1016 | RFALSE(B_LEVEL(*pcom_father) <= DISK_LEAF_NODE_LEVEL, |
1017 | "PAP-8185: (%b %z) level too small", |
1018 | *pcom_father, *pcom_father); |
1019 | |
1020 | /* Check whether the common parent is locked. */ |
1021 | |
1022 | if (buffer_locked(*pcom_father)) { |
1023 | |
1024 | /* Release the write lock while the buffer is busy */ |
1025 | reiserfs_write_unlock(tb->tb_sb); |
1026 | __wait_on_buffer(*pcom_father); |
1027 | reiserfs_write_lock(tb->tb_sb); |
1028 | if (FILESYSTEM_CHANGED_TB(tb)) { |
1029 | brelse(*pcom_father); |
1030 | return REPEAT_SEARCH; |
1031 | } |
1032 | } |
1033 | |
1034 | /* So, we got common parent of the current node and its left/right neighbor. |
1035 | Now we are geting the parent of the left/right neighbor. */ |
1036 | |
1037 | /* Form key to get parent of the left/right neighbor. */ |
1038 | le_key2cpu_key(&s_lr_father_key, |
1039 | B_N_PDELIM_KEY(*pcom_father, |
1040 | (c_lr_par == |
1041 | LEFT_PARENTS) ? (tb->lkey[h - 1] = |
1042 | position - |
1043 | 1) : (tb->rkey[h - |
1044 | 1] = |
1045 | position))); |
1046 | |
1047 | if (c_lr_par == LEFT_PARENTS) |
1048 | decrement_key(&s_lr_father_key); |
1049 | |
1050 | if (search_by_key |
1051 | (tb->tb_sb, &s_lr_father_key, &s_path_to_neighbor_father, |
1052 | h + 1) == IO_ERROR) |
1053 | // path is released |
1054 | return IO_ERROR; |
1055 | |
1056 | if (FILESYSTEM_CHANGED_TB(tb)) { |
1057 | pathrelse(&s_path_to_neighbor_father); |
1058 | brelse(*pcom_father); |
1059 | return REPEAT_SEARCH; |
1060 | } |
1061 | |
1062 | *pfather = PATH_PLAST_BUFFER(&s_path_to_neighbor_father); |
1063 | |
1064 | RFALSE(B_LEVEL(*pfather) != h + 1, |
1065 | "PAP-8190: (%b %z) level too small", *pfather, *pfather); |
1066 | RFALSE(s_path_to_neighbor_father.path_length < |
1067 | FIRST_PATH_ELEMENT_OFFSET, "PAP-8192: path length is too small"); |
1068 | |
1069 | s_path_to_neighbor_father.path_length--; |
1070 | pathrelse(&s_path_to_neighbor_father); |
1071 | return CARRY_ON; |
1072 | } |
1073 | |
1074 | /* Get parents of neighbors of node in the path(S[path_offset]) and common parents of |
1075 | * S[path_offset] and L[path_offset]/R[path_offset]: F[path_offset], FL[path_offset], |
1076 | * FR[path_offset], CFL[path_offset], CFR[path_offset]. |
1077 | * Calculate numbers of left and right delimiting keys position: lkey[path_offset], rkey[path_offset]. |
1078 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; |
1079 | * CARRY_ON - schedule didn't occur while the function worked; |
1080 | */ |
1081 | static int get_parents(struct tree_balance *tb, int h) |
1082 | { |
1083 | struct treepath *path = tb->tb_path; |
1084 | int position, |
1085 | ret, |
1086 | path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h); |
1087 | struct buffer_head *curf, *curcf; |
1088 | |
1089 | /* Current node is the root of the tree or will be root of the tree */ |
1090 | if (path_offset <= FIRST_PATH_ELEMENT_OFFSET) { |
1091 | /* The root can not have parents. |
1092 | Release nodes which previously were obtained as parents of the current node neighbors. */ |
1093 | brelse(tb->FL[h]); |
1094 | brelse(tb->CFL[h]); |
1095 | brelse(tb->FR[h]); |
1096 | brelse(tb->CFR[h]); |
1097 | tb->FL[h] = NULL; |
1098 | tb->CFL[h] = NULL; |
1099 | tb->FR[h] = NULL; |
1100 | tb->CFR[h] = NULL; |
1101 | return CARRY_ON; |
1102 | } |
1103 | |
1104 | /* Get parent FL[path_offset] of L[path_offset]. */ |
1105 | position = PATH_OFFSET_POSITION(path, path_offset - 1); |
1106 | if (position) { |
1107 | /* Current node is not the first child of its parent. */ |
1108 | curf = PATH_OFFSET_PBUFFER(path, path_offset - 1); |
1109 | curcf = PATH_OFFSET_PBUFFER(path, path_offset - 1); |
1110 | get_bh(curf); |
1111 | get_bh(curf); |
1112 | tb->lkey[h] = position - 1; |
1113 | } else { |
1114 | /* Calculate current parent of L[path_offset], which is the left neighbor of the current node. |
1115 | Calculate current common parent of L[path_offset] and the current node. Note that |
1116 | CFL[path_offset] not equal FL[path_offset] and CFL[path_offset] not equal F[path_offset]. |
1117 | Calculate lkey[path_offset]. */ |
1118 | if ((ret = get_far_parent(tb, h + 1, &curf, |
1119 | &curcf, |
1120 | LEFT_PARENTS)) != CARRY_ON) |
1121 | return ret; |
1122 | } |
1123 | |
1124 | brelse(tb->FL[h]); |
1125 | tb->FL[h] = curf; /* New initialization of FL[h]. */ |
1126 | brelse(tb->CFL[h]); |
1127 | tb->CFL[h] = curcf; /* New initialization of CFL[h]. */ |
1128 | |
1129 | RFALSE((curf && !B_IS_IN_TREE(curf)) || |
1130 | (curcf && !B_IS_IN_TREE(curcf)), |
1131 | "PAP-8195: FL (%b) or CFL (%b) is invalid", curf, curcf); |
1132 | |
1133 | /* Get parent FR[h] of R[h]. */ |
1134 | |
1135 | /* Current node is the last child of F[h]. FR[h] != F[h]. */ |
1136 | if (position == B_NR_ITEMS(PATH_H_PBUFFER(path, h + 1))) { |
1137 | /* Calculate current parent of R[h], which is the right neighbor of F[h]. |
1138 | Calculate current common parent of R[h] and current node. Note that CFR[h] |
1139 | not equal FR[path_offset] and CFR[h] not equal F[h]. */ |
1140 | if ((ret = |
1141 | get_far_parent(tb, h + 1, &curf, &curcf, |
1142 | RIGHT_PARENTS)) != CARRY_ON) |
1143 | return ret; |
1144 | } else { |
1145 | /* Current node is not the last child of its parent F[h]. */ |
1146 | curf = PATH_OFFSET_PBUFFER(path, path_offset - 1); |
1147 | curcf = PATH_OFFSET_PBUFFER(path, path_offset - 1); |
1148 | get_bh(curf); |
1149 | get_bh(curf); |
1150 | tb->rkey[h] = position; |
1151 | } |
1152 | |
1153 | brelse(tb->FR[h]); |
1154 | /* New initialization of FR[path_offset]. */ |
1155 | tb->FR[h] = curf; |
1156 | |
1157 | brelse(tb->CFR[h]); |
1158 | /* New initialization of CFR[path_offset]. */ |
1159 | tb->CFR[h] = curcf; |
1160 | |
1161 | RFALSE((curf && !B_IS_IN_TREE(curf)) || |
1162 | (curcf && !B_IS_IN_TREE(curcf)), |
1163 | "PAP-8205: FR (%b) or CFR (%b) is invalid", curf, curcf); |
1164 | |
1165 | return CARRY_ON; |
1166 | } |
1167 | |
1168 | /* it is possible to remove node as result of shiftings to |
1169 | neighbors even when we insert or paste item. */ |
1170 | static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree, |
1171 | struct tree_balance *tb, int h) |
1172 | { |
1173 | struct buffer_head *Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1174 | int levbytes = tb->insert_size[h]; |
1175 | struct item_head *ih; |
1176 | struct reiserfs_key *r_key = NULL; |
1177 | |
1178 | ih = B_N_PITEM_HEAD(Sh, 0); |
1179 | if (tb->CFR[h]) |
1180 | r_key = B_N_PDELIM_KEY(tb->CFR[h], tb->rkey[h]); |
1181 | |
1182 | if (lfree + rfree + sfree < MAX_CHILD_SIZE(Sh) + levbytes |
1183 | /* shifting may merge items which might save space */ |
1184 | - |
1185 | ((!h |
1186 | && op_is_left_mergeable(&(ih->ih_key), Sh->b_size)) ? IH_SIZE : 0) |
1187 | - |
1188 | ((!h && r_key |
1189 | && op_is_left_mergeable(r_key, Sh->b_size)) ? IH_SIZE : 0) |
1190 | + ((h) ? KEY_SIZE : 0)) { |
1191 | /* node can not be removed */ |
1192 | if (sfree >= levbytes) { /* new item fits into node S[h] without any shifting */ |
1193 | if (!h) |
1194 | tb->s0num = |
1195 | B_NR_ITEMS(Sh) + |
1196 | ((mode == M_INSERT) ? 1 : 0); |
1197 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1198 | return NO_BALANCING_NEEDED; |
1199 | } |
1200 | } |
1201 | PROC_INFO_INC(tb->tb_sb, can_node_be_removed[h]); |
1202 | return !NO_BALANCING_NEEDED; |
1203 | } |
1204 | |
1205 | /* Check whether current node S[h] is balanced when increasing its size by |
1206 | * Inserting or Pasting. |
1207 | * Calculate parameters for balancing for current level h. |
1208 | * Parameters: |
1209 | * tb tree_balance structure; |
1210 | * h current level of the node; |
1211 | * inum item number in S[h]; |
1212 | * mode i - insert, p - paste; |
1213 | * Returns: 1 - schedule occurred; |
1214 | * 0 - balancing for higher levels needed; |
1215 | * -1 - no balancing for higher levels needed; |
1216 | * -2 - no disk space. |
1217 | */ |
1218 | /* ip means Inserting or Pasting */ |
1219 | static int ip_check_balance(struct tree_balance *tb, int h) |
1220 | { |
1221 | struct virtual_node *vn = tb->tb_vn; |
1222 | int levbytes, /* Number of bytes that must be inserted into (value |
1223 | is negative if bytes are deleted) buffer which |
1224 | contains node being balanced. The mnemonic is |
1225 | that the attempted change in node space used level |
1226 | is levbytes bytes. */ |
1227 | ret; |
1228 | |
1229 | int lfree, sfree, rfree /* free space in L, S and R */ ; |
1230 | |
1231 | /* nver is short for number of vertixes, and lnver is the number if |
1232 | we shift to the left, rnver is the number if we shift to the |
1233 | right, and lrnver is the number if we shift in both directions. |
1234 | The goal is to minimize first the number of vertixes, and second, |
1235 | the number of vertixes whose contents are changed by shifting, |
1236 | and third the number of uncached vertixes whose contents are |
1237 | changed by shifting and must be read from disk. */ |
1238 | int nver, lnver, rnver, lrnver; |
1239 | |
1240 | /* used at leaf level only, S0 = S[0] is the node being balanced, |
1241 | sInum [ I = 0,1,2 ] is the number of items that will |
1242 | remain in node SI after balancing. S1 and S2 are new |
1243 | nodes that might be created. */ |
1244 | |
1245 | /* we perform 8 calls to get_num_ver(). For each call we calculate five parameters. |
1246 | where 4th parameter is s1bytes and 5th - s2bytes |
1247 | */ |
1248 | short snum012[40] = { 0, }; /* s0num, s1num, s2num for 8 cases |
1249 | 0,1 - do not shift and do not shift but bottle |
1250 | 2 - shift only whole item to left |
1251 | 3 - shift to left and bottle as much as possible |
1252 | 4,5 - shift to right (whole items and as much as possible |
1253 | 6,7 - shift to both directions (whole items and as much as possible) |
1254 | */ |
1255 | |
1256 | /* Sh is the node whose balance is currently being checked */ |
1257 | struct buffer_head *Sh; |
1258 | |
1259 | Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1260 | levbytes = tb->insert_size[h]; |
1261 | |
1262 | /* Calculate balance parameters for creating new root. */ |
1263 | if (!Sh) { |
1264 | if (!h) |
1265 | reiserfs_panic(tb->tb_sb, "vs-8210", |
1266 | "S[0] can not be 0"); |
1267 | switch (ret = get_empty_nodes(tb, h)) { |
1268 | case CARRY_ON: |
1269 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1270 | return NO_BALANCING_NEEDED; /* no balancing for higher levels needed */ |
1271 | |
1272 | case NO_DISK_SPACE: |
1273 | case REPEAT_SEARCH: |
1274 | return ret; |
1275 | default: |
1276 | reiserfs_panic(tb->tb_sb, "vs-8215", "incorrect " |
1277 | "return value of get_empty_nodes"); |
1278 | } |
1279 | } |
1280 | |
1281 | if ((ret = get_parents(tb, h)) != CARRY_ON) /* get parents of S[h] neighbors. */ |
1282 | return ret; |
1283 | |
1284 | sfree = B_FREE_SPACE(Sh); |
1285 | |
1286 | /* get free space of neighbors */ |
1287 | rfree = get_rfree(tb, h); |
1288 | lfree = get_lfree(tb, h); |
1289 | |
1290 | if (can_node_be_removed(vn->vn_mode, lfree, sfree, rfree, tb, h) == |
1291 | NO_BALANCING_NEEDED) |
1292 | /* and new item fits into node S[h] without any shifting */ |
1293 | return NO_BALANCING_NEEDED; |
1294 | |
1295 | create_virtual_node(tb, h); |
1296 | |
1297 | /* |
1298 | determine maximal number of items we can shift to the left neighbor (in tb structure) |
1299 | and the maximal number of bytes that can flow to the left neighbor |
1300 | from the left most liquid item that cannot be shifted from S[0] entirely (returned value) |
1301 | */ |
1302 | check_left(tb, h, lfree); |
1303 | |
1304 | /* |
1305 | determine maximal number of items we can shift to the right neighbor (in tb structure) |
1306 | and the maximal number of bytes that can flow to the right neighbor |
1307 | from the right most liquid item that cannot be shifted from S[0] entirely (returned value) |
1308 | */ |
1309 | check_right(tb, h, rfree); |
1310 | |
1311 | /* all contents of internal node S[h] can be moved into its |
1312 | neighbors, S[h] will be removed after balancing */ |
1313 | if (h && (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1)) { |
1314 | int to_r; |
1315 | |
1316 | /* Since we are working on internal nodes, and our internal |
1317 | nodes have fixed size entries, then we can balance by the |
1318 | number of items rather than the space they consume. In this |
1319 | routine we set the left node equal to the right node, |
1320 | allowing a difference of less than or equal to 1 child |
1321 | pointer. */ |
1322 | to_r = |
1323 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] + |
1324 | vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - |
1325 | tb->rnum[h]); |
1326 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL, |
1327 | -1, -1); |
1328 | return CARRY_ON; |
1329 | } |
1330 | |
1331 | /* this checks balance condition, that any two neighboring nodes can not fit in one node */ |
1332 | RFALSE(h && |
1333 | (tb->lnum[h] >= vn->vn_nr_item + 1 || |
1334 | tb->rnum[h] >= vn->vn_nr_item + 1), |
1335 | "vs-8220: tree is not balanced on internal level"); |
1336 | RFALSE(!h && ((tb->lnum[h] >= vn->vn_nr_item && (tb->lbytes == -1)) || |
1337 | (tb->rnum[h] >= vn->vn_nr_item && (tb->rbytes == -1))), |
1338 | "vs-8225: tree is not balanced on leaf level"); |
1339 | |
1340 | /* all contents of S[0] can be moved into its neighbors |
1341 | S[0] will be removed after balancing. */ |
1342 | if (!h && is_leaf_removable(tb)) |
1343 | return CARRY_ON; |
1344 | |
1345 | /* why do we perform this check here rather than earlier?? |
1346 | Answer: we can win 1 node in some cases above. Moreover we |
1347 | checked it above, when we checked, that S[0] is not removable |
1348 | in principle */ |
1349 | if (sfree >= levbytes) { /* new item fits into node S[h] without any shifting */ |
1350 | if (!h) |
1351 | tb->s0num = vn->vn_nr_item; |
1352 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1353 | return NO_BALANCING_NEEDED; |
1354 | } |
1355 | |
1356 | { |
1357 | int lpar, rpar, nset, lset, rset, lrset; |
1358 | /* |
1359 | * regular overflowing of the node |
1360 | */ |
1361 | |
1362 | /* get_num_ver works in 2 modes (FLOW & NO_FLOW) |
1363 | lpar, rpar - number of items we can shift to left/right neighbor (including splitting item) |
1364 | nset, lset, rset, lrset - shows, whether flowing items give better packing |
1365 | */ |
1366 | #define FLOW 1 |
1367 | #define NO_FLOW 0 /* do not any splitting */ |
1368 | |
1369 | /* we choose one the following */ |
1370 | #define NOTHING_SHIFT_NO_FLOW 0 |
1371 | #define NOTHING_SHIFT_FLOW 5 |
1372 | #define LEFT_SHIFT_NO_FLOW 10 |
1373 | #define LEFT_SHIFT_FLOW 15 |
1374 | #define RIGHT_SHIFT_NO_FLOW 20 |
1375 | #define RIGHT_SHIFT_FLOW 25 |
1376 | #define LR_SHIFT_NO_FLOW 30 |
1377 | #define LR_SHIFT_FLOW 35 |
1378 | |
1379 | lpar = tb->lnum[h]; |
1380 | rpar = tb->rnum[h]; |
1381 | |
1382 | /* calculate number of blocks S[h] must be split into when |
1383 | nothing is shifted to the neighbors, |
1384 | as well as number of items in each part of the split node (s012 numbers), |
1385 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any */ |
1386 | nset = NOTHING_SHIFT_NO_FLOW; |
1387 | nver = get_num_ver(vn->vn_mode, tb, h, |
1388 | 0, -1, h ? vn->vn_nr_item : 0, -1, |
1389 | snum012, NO_FLOW); |
1390 | |
1391 | if (!h) { |
1392 | int nver1; |
1393 | |
1394 | /* note, that in this case we try to bottle between S[0] and S1 (S1 - the first new node) */ |
1395 | nver1 = get_num_ver(vn->vn_mode, tb, h, |
1396 | 0, -1, 0, -1, |
1397 | snum012 + NOTHING_SHIFT_FLOW, FLOW); |
1398 | if (nver > nver1) |
1399 | nset = NOTHING_SHIFT_FLOW, nver = nver1; |
1400 | } |
1401 | |
1402 | /* calculate number of blocks S[h] must be split into when |
1403 | l_shift_num first items and l_shift_bytes of the right most |
1404 | liquid item to be shifted are shifted to the left neighbor, |
1405 | as well as number of items in each part of the splitted node (s012 numbers), |
1406 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any |
1407 | */ |
1408 | lset = LEFT_SHIFT_NO_FLOW; |
1409 | lnver = get_num_ver(vn->vn_mode, tb, h, |
1410 | lpar - ((h || tb->lbytes == -1) ? 0 : 1), |
1411 | -1, h ? vn->vn_nr_item : 0, -1, |
1412 | snum012 + LEFT_SHIFT_NO_FLOW, NO_FLOW); |
1413 | if (!h) { |
1414 | int lnver1; |
1415 | |
1416 | lnver1 = get_num_ver(vn->vn_mode, tb, h, |
1417 | lpar - |
1418 | ((tb->lbytes != -1) ? 1 : 0), |
1419 | tb->lbytes, 0, -1, |
1420 | snum012 + LEFT_SHIFT_FLOW, FLOW); |
1421 | if (lnver > lnver1) |
1422 | lset = LEFT_SHIFT_FLOW, lnver = lnver1; |
1423 | } |
1424 | |
1425 | /* calculate number of blocks S[h] must be split into when |
1426 | r_shift_num first items and r_shift_bytes of the left most |
1427 | liquid item to be shifted are shifted to the right neighbor, |
1428 | as well as number of items in each part of the splitted node (s012 numbers), |
1429 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any |
1430 | */ |
1431 | rset = RIGHT_SHIFT_NO_FLOW; |
1432 | rnver = get_num_ver(vn->vn_mode, tb, h, |
1433 | 0, -1, |
1434 | h ? (vn->vn_nr_item - rpar) : (rpar - |
1435 | ((tb-> |
1436 | rbytes != |
1437 | -1) ? 1 : |
1438 | 0)), -1, |
1439 | snum012 + RIGHT_SHIFT_NO_FLOW, NO_FLOW); |
1440 | if (!h) { |
1441 | int rnver1; |
1442 | |
1443 | rnver1 = get_num_ver(vn->vn_mode, tb, h, |
1444 | 0, -1, |
1445 | (rpar - |
1446 | ((tb->rbytes != -1) ? 1 : 0)), |
1447 | tb->rbytes, |
1448 | snum012 + RIGHT_SHIFT_FLOW, FLOW); |
1449 | |
1450 | if (rnver > rnver1) |
1451 | rset = RIGHT_SHIFT_FLOW, rnver = rnver1; |
1452 | } |
1453 | |
1454 | /* calculate number of blocks S[h] must be split into when |
1455 | items are shifted in both directions, |
1456 | as well as number of items in each part of the splitted node (s012 numbers), |
1457 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any |
1458 | */ |
1459 | lrset = LR_SHIFT_NO_FLOW; |
1460 | lrnver = get_num_ver(vn->vn_mode, tb, h, |
1461 | lpar - ((h || tb->lbytes == -1) ? 0 : 1), |
1462 | -1, |
1463 | h ? (vn->vn_nr_item - rpar) : (rpar - |
1464 | ((tb-> |
1465 | rbytes != |
1466 | -1) ? 1 : |
1467 | 0)), -1, |
1468 | snum012 + LR_SHIFT_NO_FLOW, NO_FLOW); |
1469 | if (!h) { |
1470 | int lrnver1; |
1471 | |
1472 | lrnver1 = get_num_ver(vn->vn_mode, tb, h, |
1473 | lpar - |
1474 | ((tb->lbytes != -1) ? 1 : 0), |
1475 | tb->lbytes, |
1476 | (rpar - |
1477 | ((tb->rbytes != -1) ? 1 : 0)), |
1478 | tb->rbytes, |
1479 | snum012 + LR_SHIFT_FLOW, FLOW); |
1480 | if (lrnver > lrnver1) |
1481 | lrset = LR_SHIFT_FLOW, lrnver = lrnver1; |
1482 | } |
1483 | |
1484 | /* Our general shifting strategy is: |
1485 | 1) to minimized number of new nodes; |
1486 | 2) to minimized number of neighbors involved in shifting; |
1487 | 3) to minimized number of disk reads; */ |
1488 | |
1489 | /* we can win TWO or ONE nodes by shifting in both directions */ |
1490 | if (lrnver < lnver && lrnver < rnver) { |
1491 | RFALSE(h && |
1492 | (tb->lnum[h] != 1 || |
1493 | tb->rnum[h] != 1 || |
1494 | lrnver != 1 || rnver != 2 || lnver != 2 |
1495 | || h != 1), "vs-8230: bad h"); |
1496 | if (lrset == LR_SHIFT_FLOW) |
1497 | set_parameters(tb, h, tb->lnum[h], tb->rnum[h], |
1498 | lrnver, snum012 + lrset, |
1499 | tb->lbytes, tb->rbytes); |
1500 | else |
1501 | set_parameters(tb, h, |
1502 | tb->lnum[h] - |
1503 | ((tb->lbytes == -1) ? 0 : 1), |
1504 | tb->rnum[h] - |
1505 | ((tb->rbytes == -1) ? 0 : 1), |
1506 | lrnver, snum012 + lrset, -1, -1); |
1507 | |
1508 | return CARRY_ON; |
1509 | } |
1510 | |
1511 | /* if shifting doesn't lead to better packing then don't shift */ |
1512 | if (nver == lrnver) { |
1513 | set_parameters(tb, h, 0, 0, nver, snum012 + nset, -1, |
1514 | -1); |
1515 | return CARRY_ON; |
1516 | } |
1517 | |
1518 | /* now we know that for better packing shifting in only one |
1519 | direction either to the left or to the right is required */ |
1520 | |
1521 | /* if shifting to the left is better than shifting to the right */ |
1522 | if (lnver < rnver) { |
1523 | SET_PAR_SHIFT_LEFT; |
1524 | return CARRY_ON; |
1525 | } |
1526 | |
1527 | /* if shifting to the right is better than shifting to the left */ |
1528 | if (lnver > rnver) { |
1529 | SET_PAR_SHIFT_RIGHT; |
1530 | return CARRY_ON; |
1531 | } |
1532 | |
1533 | /* now shifting in either direction gives the same number |
1534 | of nodes and we can make use of the cached neighbors */ |
1535 | if (is_left_neighbor_in_cache(tb, h)) { |
1536 | SET_PAR_SHIFT_LEFT; |
1537 | return CARRY_ON; |
1538 | } |
1539 | |
1540 | /* shift to the right independently on whether the right neighbor in cache or not */ |
1541 | SET_PAR_SHIFT_RIGHT; |
1542 | return CARRY_ON; |
1543 | } |
1544 | } |
1545 | |
1546 | /* Check whether current node S[h] is balanced when Decreasing its size by |
1547 | * Deleting or Cutting for INTERNAL node of S+tree. |
1548 | * Calculate parameters for balancing for current level h. |
1549 | * Parameters: |
1550 | * tb tree_balance structure; |
1551 | * h current level of the node; |
1552 | * inum item number in S[h]; |
1553 | * mode i - insert, p - paste; |
1554 | * Returns: 1 - schedule occurred; |
1555 | * 0 - balancing for higher levels needed; |
1556 | * -1 - no balancing for higher levels needed; |
1557 | * -2 - no disk space. |
1558 | * |
1559 | * Note: Items of internal nodes have fixed size, so the balance condition for |
1560 | * the internal part of S+tree is as for the B-trees. |
1561 | */ |
1562 | static int dc_check_balance_internal(struct tree_balance *tb, int h) |
1563 | { |
1564 | struct virtual_node *vn = tb->tb_vn; |
1565 | |
1566 | /* Sh is the node whose balance is currently being checked, |
1567 | and Fh is its father. */ |
1568 | struct buffer_head *Sh, *Fh; |
1569 | int maxsize, ret; |
1570 | int lfree, rfree /* free space in L and R */ ; |
1571 | |
1572 | Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1573 | Fh = PATH_H_PPARENT(tb->tb_path, h); |
1574 | |
1575 | maxsize = MAX_CHILD_SIZE(Sh); |
1576 | |
1577 | /* using tb->insert_size[h], which is negative in this case, create_virtual_node calculates: */ |
1578 | /* new_nr_item = number of items node would have if operation is */ |
1579 | /* performed without balancing (new_nr_item); */ |
1580 | create_virtual_node(tb, h); |
1581 | |
1582 | if (!Fh) { /* S[h] is the root. */ |
1583 | if (vn->vn_nr_item > 0) { |
1584 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1585 | return NO_BALANCING_NEEDED; /* no balancing for higher levels needed */ |
1586 | } |
1587 | /* new_nr_item == 0. |
1588 | * Current root will be deleted resulting in |
1589 | * decrementing the tree height. */ |
1590 | set_parameters(tb, h, 0, 0, 0, NULL, -1, -1); |
1591 | return CARRY_ON; |
1592 | } |
1593 | |
1594 | if ((ret = get_parents(tb, h)) != CARRY_ON) |
1595 | return ret; |
1596 | |
1597 | /* get free space of neighbors */ |
1598 | rfree = get_rfree(tb, h); |
1599 | lfree = get_lfree(tb, h); |
1600 | |
1601 | /* determine maximal number of items we can fit into neighbors */ |
1602 | check_left(tb, h, lfree); |
1603 | check_right(tb, h, rfree); |
1604 | |
1605 | if (vn->vn_nr_item >= MIN_NR_KEY(Sh)) { /* Balance condition for the internal node is valid. |
1606 | * In this case we balance only if it leads to better packing. */ |
1607 | if (vn->vn_nr_item == MIN_NR_KEY(Sh)) { /* Here we join S[h] with one of its neighbors, |
1608 | * which is impossible with greater values of new_nr_item. */ |
1609 | if (tb->lnum[h] >= vn->vn_nr_item + 1) { |
1610 | /* All contents of S[h] can be moved to L[h]. */ |
1611 | int n; |
1612 | int order_L; |
1613 | |
1614 | order_L = |
1615 | ((n = |
1616 | PATH_H_B_ITEM_ORDER(tb->tb_path, |
1617 | h)) == |
1618 | 0) ? B_NR_ITEMS(tb->FL[h]) : n - 1; |
1619 | n = dc_size(B_N_CHILD(tb->FL[h], order_L)) / |
1620 | (DC_SIZE + KEY_SIZE); |
1621 | set_parameters(tb, h, -n - 1, 0, 0, NULL, -1, |
1622 | -1); |
1623 | return CARRY_ON; |
1624 | } |
1625 | |
1626 | if (tb->rnum[h] >= vn->vn_nr_item + 1) { |
1627 | /* All contents of S[h] can be moved to R[h]. */ |
1628 | int n; |
1629 | int order_R; |
1630 | |
1631 | order_R = |
1632 | ((n = |
1633 | PATH_H_B_ITEM_ORDER(tb->tb_path, |
1634 | h)) == |
1635 | B_NR_ITEMS(Fh)) ? 0 : n + 1; |
1636 | n = dc_size(B_N_CHILD(tb->FR[h], order_R)) / |
1637 | (DC_SIZE + KEY_SIZE); |
1638 | set_parameters(tb, h, 0, -n - 1, 0, NULL, -1, |
1639 | -1); |
1640 | return CARRY_ON; |
1641 | } |
1642 | } |
1643 | |
1644 | if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) { |
1645 | /* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */ |
1646 | int to_r; |
1647 | |
1648 | to_r = |
1649 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - |
1650 | tb->rnum[h] + vn->vn_nr_item + 1) / 2 - |
1651 | (MAX_NR_KEY(Sh) + 1 - tb->rnum[h]); |
1652 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, |
1653 | 0, NULL, -1, -1); |
1654 | return CARRY_ON; |
1655 | } |
1656 | |
1657 | /* Balancing does not lead to better packing. */ |
1658 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1659 | return NO_BALANCING_NEEDED; |
1660 | } |
1661 | |
1662 | /* Current node contain insufficient number of items. Balancing is required. */ |
1663 | /* Check whether we can merge S[h] with left neighbor. */ |
1664 | if (tb->lnum[h] >= vn->vn_nr_item + 1) |
1665 | if (is_left_neighbor_in_cache(tb, h) |
1666 | || tb->rnum[h] < vn->vn_nr_item + 1 || !tb->FR[h]) { |
1667 | int n; |
1668 | int order_L; |
1669 | |
1670 | order_L = |
1671 | ((n = |
1672 | PATH_H_B_ITEM_ORDER(tb->tb_path, |
1673 | h)) == |
1674 | 0) ? B_NR_ITEMS(tb->FL[h]) : n - 1; |
1675 | n = dc_size(B_N_CHILD(tb->FL[h], order_L)) / (DC_SIZE + |
1676 | KEY_SIZE); |
1677 | set_parameters(tb, h, -n - 1, 0, 0, NULL, -1, -1); |
1678 | return CARRY_ON; |
1679 | } |
1680 | |
1681 | /* Check whether we can merge S[h] with right neighbor. */ |
1682 | if (tb->rnum[h] >= vn->vn_nr_item + 1) { |
1683 | int n; |
1684 | int order_R; |
1685 | |
1686 | order_R = |
1687 | ((n = |
1688 | PATH_H_B_ITEM_ORDER(tb->tb_path, |
1689 | h)) == B_NR_ITEMS(Fh)) ? 0 : (n + 1); |
1690 | n = dc_size(B_N_CHILD(tb->FR[h], order_R)) / (DC_SIZE + |
1691 | KEY_SIZE); |
1692 | set_parameters(tb, h, 0, -n - 1, 0, NULL, -1, -1); |
1693 | return CARRY_ON; |
1694 | } |
1695 | |
1696 | /* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */ |
1697 | if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) { |
1698 | int to_r; |
1699 | |
1700 | to_r = |
1701 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] + |
1702 | vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - |
1703 | tb->rnum[h]); |
1704 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL, |
1705 | -1, -1); |
1706 | return CARRY_ON; |
1707 | } |
1708 | |
1709 | /* For internal nodes try to borrow item from a neighbor */ |
1710 | RFALSE(!tb->FL[h] && !tb->FR[h], "vs-8235: trying to borrow for root"); |
1711 | |
1712 | /* Borrow one or two items from caching neighbor */ |
1713 | if (is_left_neighbor_in_cache(tb, h) || !tb->FR[h]) { |
1714 | int from_l; |
1715 | |
1716 | from_l = |
1717 | (MAX_NR_KEY(Sh) + 1 - tb->lnum[h] + vn->vn_nr_item + |
1718 | 1) / 2 - (vn->vn_nr_item + 1); |
1719 | set_parameters(tb, h, -from_l, 0, 1, NULL, -1, -1); |
1720 | return CARRY_ON; |
1721 | } |
1722 | |
1723 | set_parameters(tb, h, 0, |
1724 | -((MAX_NR_KEY(Sh) + 1 - tb->rnum[h] + vn->vn_nr_item + |
1725 | 1) / 2 - (vn->vn_nr_item + 1)), 1, NULL, -1, -1); |
1726 | return CARRY_ON; |
1727 | } |
1728 | |
1729 | /* Check whether current node S[h] is balanced when Decreasing its size by |
1730 | * Deleting or Truncating for LEAF node of S+tree. |
1731 | * Calculate parameters for balancing for current level h. |
1732 | * Parameters: |
1733 | * tb tree_balance structure; |
1734 | * h current level of the node; |
1735 | * inum item number in S[h]; |
1736 | * mode i - insert, p - paste; |
1737 | * Returns: 1 - schedule occurred; |
1738 | * 0 - balancing for higher levels needed; |
1739 | * -1 - no balancing for higher levels needed; |
1740 | * -2 - no disk space. |
1741 | */ |
1742 | static int dc_check_balance_leaf(struct tree_balance *tb, int h) |
1743 | { |
1744 | struct virtual_node *vn = tb->tb_vn; |
1745 | |
1746 | /* Number of bytes that must be deleted from |
1747 | (value is negative if bytes are deleted) buffer which |
1748 | contains node being balanced. The mnemonic is that the |
1749 | attempted change in node space used level is levbytes bytes. */ |
1750 | int levbytes; |
1751 | /* the maximal item size */ |
1752 | int maxsize, ret; |
1753 | /* S0 is the node whose balance is currently being checked, |
1754 | and F0 is its father. */ |
1755 | struct buffer_head *S0, *F0; |
1756 | int lfree, rfree /* free space in L and R */ ; |
1757 | |
1758 | S0 = PATH_H_PBUFFER(tb->tb_path, 0); |
1759 | F0 = PATH_H_PPARENT(tb->tb_path, 0); |
1760 | |
1761 | levbytes = tb->insert_size[h]; |
1762 | |
1763 | maxsize = MAX_CHILD_SIZE(S0); /* maximal possible size of an item */ |
1764 | |
1765 | if (!F0) { /* S[0] is the root now. */ |
1766 | |
1767 | RFALSE(-levbytes >= maxsize - B_FREE_SPACE(S0), |
1768 | "vs-8240: attempt to create empty buffer tree"); |
1769 | |
1770 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1771 | return NO_BALANCING_NEEDED; |
1772 | } |
1773 | |
1774 | if ((ret = get_parents(tb, h)) != CARRY_ON) |
1775 | return ret; |
1776 | |
1777 | /* get free space of neighbors */ |
1778 | rfree = get_rfree(tb, h); |
1779 | lfree = get_lfree(tb, h); |
1780 | |
1781 | create_virtual_node(tb, h); |
1782 | |
1783 | /* if 3 leaves can be merge to one, set parameters and return */ |
1784 | if (are_leaves_removable(tb, lfree, rfree)) |
1785 | return CARRY_ON; |
1786 | |
1787 | /* determine maximal number of items we can shift to the left/right neighbor |
1788 | and the maximal number of bytes that can flow to the left/right neighbor |
1789 | from the left/right most liquid item that cannot be shifted from S[0] entirely |
1790 | */ |
1791 | check_left(tb, h, lfree); |
1792 | check_right(tb, h, rfree); |
1793 | |
1794 | /* check whether we can merge S with left neighbor. */ |
1795 | if (tb->lnum[0] >= vn->vn_nr_item && tb->lbytes == -1) |
1796 | if (is_left_neighbor_in_cache(tb, h) || ((tb->rnum[0] - ((tb->rbytes == -1) ? 0 : 1)) < vn->vn_nr_item) || /* S can not be merged with R */ |
1797 | !tb->FR[h]) { |
1798 | |
1799 | RFALSE(!tb->FL[h], |
1800 | "vs-8245: dc_check_balance_leaf: FL[h] must exist"); |
1801 | |
1802 | /* set parameter to merge S[0] with its left neighbor */ |
1803 | set_parameters(tb, h, -1, 0, 0, NULL, -1, -1); |
1804 | return CARRY_ON; |
1805 | } |
1806 | |
1807 | /* check whether we can merge S[0] with right neighbor. */ |
1808 | if (tb->rnum[0] >= vn->vn_nr_item && tb->rbytes == -1) { |
1809 | set_parameters(tb, h, 0, -1, 0, NULL, -1, -1); |
1810 | return CARRY_ON; |
1811 | } |
1812 | |
1813 | /* All contents of S[0] can be moved to the neighbors (L[0] & R[0]). Set parameters and return */ |
1814 | if (is_leaf_removable(tb)) |
1815 | return CARRY_ON; |
1816 | |
1817 | /* Balancing is not required. */ |
1818 | tb->s0num = vn->vn_nr_item; |
1819 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); |
1820 | return NO_BALANCING_NEEDED; |
1821 | } |
1822 | |
1823 | /* Check whether current node S[h] is balanced when Decreasing its size by |
1824 | * Deleting or Cutting. |
1825 | * Calculate parameters for balancing for current level h. |
1826 | * Parameters: |
1827 | * tb tree_balance structure; |
1828 | * h current level of the node; |
1829 | * inum item number in S[h]; |
1830 | * mode d - delete, c - cut. |
1831 | * Returns: 1 - schedule occurred; |
1832 | * 0 - balancing for higher levels needed; |
1833 | * -1 - no balancing for higher levels needed; |
1834 | * -2 - no disk space. |
1835 | */ |
1836 | static int dc_check_balance(struct tree_balance *tb, int h) |
1837 | { |
1838 | RFALSE(!(PATH_H_PBUFFER(tb->tb_path, h)), |
1839 | "vs-8250: S is not initialized"); |
1840 | |
1841 | if (h) |
1842 | return dc_check_balance_internal(tb, h); |
1843 | else |
1844 | return dc_check_balance_leaf(tb, h); |
1845 | } |
1846 | |
1847 | /* Check whether current node S[h] is balanced. |
1848 | * Calculate parameters for balancing for current level h. |
1849 | * Parameters: |
1850 | * |
1851 | * tb tree_balance structure: |
1852 | * |
1853 | * tb is a large structure that must be read about in the header file |
1854 | * at the same time as this procedure if the reader is to successfully |
1855 | * understand this procedure |
1856 | * |
1857 | * h current level of the node; |
1858 | * inum item number in S[h]; |
1859 | * mode i - insert, p - paste, d - delete, c - cut. |
1860 | * Returns: 1 - schedule occurred; |
1861 | * 0 - balancing for higher levels needed; |
1862 | * -1 - no balancing for higher levels needed; |
1863 | * -2 - no disk space. |
1864 | */ |
1865 | static int check_balance(int mode, |
1866 | struct tree_balance *tb, |
1867 | int h, |
1868 | int inum, |
1869 | int pos_in_item, |
1870 | struct item_head *ins_ih, const void *data) |
1871 | { |
1872 | struct virtual_node *vn; |
1873 | |
1874 | vn = tb->tb_vn = (struct virtual_node *)(tb->vn_buf); |
1875 | vn->vn_free_ptr = (char *)(tb->tb_vn + 1); |
1876 | vn->vn_mode = mode; |
1877 | vn->vn_affected_item_num = inum; |
1878 | vn->vn_pos_in_item = pos_in_item; |
1879 | vn->vn_ins_ih = ins_ih; |
1880 | vn->vn_data = data; |
1881 | |
1882 | RFALSE(mode == M_INSERT && !vn->vn_ins_ih, |
1883 | "vs-8255: ins_ih can not be 0 in insert mode"); |
1884 | |
1885 | if (tb->insert_size[h] > 0) |
1886 | /* Calculate balance parameters when size of node is increasing. */ |
1887 | return ip_check_balance(tb, h); |
1888 | |
1889 | /* Calculate balance parameters when size of node is decreasing. */ |
1890 | return dc_check_balance(tb, h); |
1891 | } |
1892 | |
1893 | /* Check whether parent at the path is the really parent of the current node.*/ |
1894 | static int get_direct_parent(struct tree_balance *tb, int h) |
1895 | { |
1896 | struct buffer_head *bh; |
1897 | struct treepath *path = tb->tb_path; |
1898 | int position, |
1899 | path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h); |
1900 | |
1901 | /* We are in the root or in the new root. */ |
1902 | if (path_offset <= FIRST_PATH_ELEMENT_OFFSET) { |
1903 | |
1904 | RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET - 1, |
1905 | "PAP-8260: invalid offset in the path"); |
1906 | |
1907 | if (PATH_OFFSET_PBUFFER(path, FIRST_PATH_ELEMENT_OFFSET)-> |
1908 | b_blocknr == SB_ROOT_BLOCK(tb->tb_sb)) { |
1909 | /* Root is not changed. */ |
1910 | PATH_OFFSET_PBUFFER(path, path_offset - 1) = NULL; |
1911 | PATH_OFFSET_POSITION(path, path_offset - 1) = 0; |
1912 | return CARRY_ON; |
1913 | } |
1914 | return REPEAT_SEARCH; /* Root is changed and we must recalculate the path. */ |
1915 | } |
1916 | |
1917 | if (!B_IS_IN_TREE |
1918 | (bh = PATH_OFFSET_PBUFFER(path, path_offset - 1))) |
1919 | return REPEAT_SEARCH; /* Parent in the path is not in the tree. */ |
1920 | |
1921 | if ((position = |
1922 | PATH_OFFSET_POSITION(path, |
1923 | path_offset - 1)) > B_NR_ITEMS(bh)) |
1924 | return REPEAT_SEARCH; |
1925 | |
1926 | if (B_N_CHILD_NUM(bh, position) != |
1927 | PATH_OFFSET_PBUFFER(path, path_offset)->b_blocknr) |
1928 | /* Parent in the path is not parent of the current node in the tree. */ |
1929 | return REPEAT_SEARCH; |
1930 | |
1931 | if (buffer_locked(bh)) { |
1932 | reiserfs_write_unlock(tb->tb_sb); |
1933 | __wait_on_buffer(bh); |
1934 | reiserfs_write_lock(tb->tb_sb); |
1935 | if (FILESYSTEM_CHANGED_TB(tb)) |
1936 | return REPEAT_SEARCH; |
1937 | } |
1938 | |
1939 | return CARRY_ON; /* Parent in the path is unlocked and really parent of the current node. */ |
1940 | } |
1941 | |
1942 | /* Using lnum[h] and rnum[h] we should determine what neighbors |
1943 | * of S[h] we |
1944 | * need in order to balance S[h], and get them if necessary. |
1945 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; |
1946 | * CARRY_ON - schedule didn't occur while the function worked; |
1947 | */ |
1948 | static int get_neighbors(struct tree_balance *tb, int h) |
1949 | { |
1950 | int child_position, |
1951 | path_offset = PATH_H_PATH_OFFSET(tb->tb_path, h + 1); |
1952 | unsigned long son_number; |
1953 | struct super_block *sb = tb->tb_sb; |
1954 | struct buffer_head *bh; |
1955 | |
1956 | PROC_INFO_INC(sb, get_neighbors[h]); |
1957 | |
1958 | if (tb->lnum[h]) { |
1959 | /* We need left neighbor to balance S[h]. */ |
1960 | PROC_INFO_INC(sb, need_l_neighbor[h]); |
1961 | bh = PATH_OFFSET_PBUFFER(tb->tb_path, path_offset); |
1962 | |
1963 | RFALSE(bh == tb->FL[h] && |
1964 | !PATH_OFFSET_POSITION(tb->tb_path, path_offset), |
1965 | "PAP-8270: invalid position in the parent"); |
1966 | |
1967 | child_position = |
1968 | (bh == |
1969 | tb->FL[h]) ? tb->lkey[h] : B_NR_ITEMS(tb-> |
1970 | FL[h]); |
1971 | son_number = B_N_CHILD_NUM(tb->FL[h], child_position); |
1972 | reiserfs_write_unlock(sb); |
1973 | bh = sb_bread(sb, son_number); |
1974 | reiserfs_write_lock(sb); |
1975 | if (!bh) |
1976 | return IO_ERROR; |
1977 | if (FILESYSTEM_CHANGED_TB(tb)) { |
1978 | brelse(bh); |
1979 | PROC_INFO_INC(sb, get_neighbors_restart[h]); |
1980 | return REPEAT_SEARCH; |
1981 | } |
1982 | |
1983 | RFALSE(!B_IS_IN_TREE(tb->FL[h]) || |
1984 | child_position > B_NR_ITEMS(tb->FL[h]) || |
1985 | B_N_CHILD_NUM(tb->FL[h], child_position) != |
1986 | bh->b_blocknr, "PAP-8275: invalid parent"); |
1987 | RFALSE(!B_IS_IN_TREE(bh), "PAP-8280: invalid child"); |
1988 | RFALSE(!h && |
1989 | B_FREE_SPACE(bh) != |
1990 | MAX_CHILD_SIZE(bh) - |
1991 | dc_size(B_N_CHILD(tb->FL[0], child_position)), |
1992 | "PAP-8290: invalid child size of left neighbor"); |
1993 | |
1994 | brelse(tb->L[h]); |
1995 | tb->L[h] = bh; |
1996 | } |
1997 | |
1998 | /* We need right neighbor to balance S[path_offset]. */ |
1999 | if (tb->rnum[h]) { /* We need right neighbor to balance S[path_offset]. */ |
2000 | PROC_INFO_INC(sb, need_r_neighbor[h]); |
2001 | bh = PATH_OFFSET_PBUFFER(tb->tb_path, path_offset); |
2002 | |
2003 | RFALSE(bh == tb->FR[h] && |
2004 | PATH_OFFSET_POSITION(tb->tb_path, |
2005 | path_offset) >= |
2006 | B_NR_ITEMS(bh), |
2007 | "PAP-8295: invalid position in the parent"); |
2008 | |
2009 | child_position = |
2010 | (bh == tb->FR[h]) ? tb->rkey[h] + 1 : 0; |
2011 | son_number = B_N_CHILD_NUM(tb->FR[h], child_position); |
2012 | reiserfs_write_unlock(sb); |
2013 | bh = sb_bread(sb, son_number); |
2014 | reiserfs_write_lock(sb); |
2015 | if (!bh) |
2016 | return IO_ERROR; |
2017 | if (FILESYSTEM_CHANGED_TB(tb)) { |
2018 | brelse(bh); |
2019 | PROC_INFO_INC(sb, get_neighbors_restart[h]); |
2020 | return REPEAT_SEARCH; |
2021 | } |
2022 | brelse(tb->R[h]); |
2023 | tb->R[h] = bh; |
2024 | |
2025 | RFALSE(!h |
2026 | && B_FREE_SPACE(bh) != |
2027 | MAX_CHILD_SIZE(bh) - |
2028 | dc_size(B_N_CHILD(tb->FR[0], child_position)), |
2029 | "PAP-8300: invalid child size of right neighbor (%d != %d - %d)", |
2030 | B_FREE_SPACE(bh), MAX_CHILD_SIZE(bh), |
2031 | dc_size(B_N_CHILD(tb->FR[0], child_position))); |
2032 | |
2033 | } |
2034 | return CARRY_ON; |
2035 | } |
2036 | |
2037 | static int get_virtual_node_size(struct super_block *sb, struct buffer_head *bh) |
2038 | { |
2039 | int max_num_of_items; |
2040 | int max_num_of_entries; |
2041 | unsigned long blocksize = sb->s_blocksize; |
2042 | |
2043 | #define MIN_NAME_LEN 1 |
2044 | |
2045 | max_num_of_items = (blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN); |
2046 | max_num_of_entries = (blocksize - BLKH_SIZE - IH_SIZE) / |
2047 | (DEH_SIZE + MIN_NAME_LEN); |
2048 | |
2049 | return sizeof(struct virtual_node) + |
2050 | max(max_num_of_items * sizeof(struct virtual_item), |
2051 | sizeof(struct virtual_item) + sizeof(struct direntry_uarea) + |
2052 | (max_num_of_entries - 1) * sizeof(__u16)); |
2053 | } |
2054 | |
2055 | /* maybe we should fail balancing we are going to perform when kmalloc |
2056 | fails several times. But now it will loop until kmalloc gets |
2057 | required memory */ |
2058 | static int get_mem_for_virtual_node(struct tree_balance *tb) |
2059 | { |
2060 | int check_fs = 0; |
2061 | int size; |
2062 | char *buf; |
2063 | |
2064 | size = get_virtual_node_size(tb->tb_sb, PATH_PLAST_BUFFER(tb->tb_path)); |
2065 | |
2066 | if (size > tb->vn_buf_size) { |
2067 | /* we have to allocate more memory for virtual node */ |
2068 | if (tb->vn_buf) { |
2069 | /* free memory allocated before */ |
2070 | kfree(tb->vn_buf); |
2071 | /* this is not needed if kfree is atomic */ |
2072 | check_fs = 1; |
2073 | } |
2074 | |
2075 | /* virtual node requires now more memory */ |
2076 | tb->vn_buf_size = size; |
2077 | |
2078 | /* get memory for virtual item */ |
2079 | buf = kmalloc(size, GFP_ATOMIC | __GFP_NOWARN); |
2080 | if (!buf) { |
2081 | /* getting memory with GFP_KERNEL priority may involve |
2082 | balancing now (due to indirect_to_direct conversion on |
2083 | dcache shrinking). So, release path and collected |
2084 | resources here */ |
2085 | free_buffers_in_tb(tb); |
2086 | buf = kmalloc(size, GFP_NOFS); |
2087 | if (!buf) { |
2088 | tb->vn_buf_size = 0; |
2089 | } |
2090 | tb->vn_buf = buf; |
2091 | schedule(); |
2092 | return REPEAT_SEARCH; |
2093 | } |
2094 | |
2095 | tb->vn_buf = buf; |
2096 | } |
2097 | |
2098 | if (check_fs && FILESYSTEM_CHANGED_TB(tb)) |
2099 | return REPEAT_SEARCH; |
2100 | |
2101 | return CARRY_ON; |
2102 | } |
2103 | |
2104 | #ifdef CONFIG_REISERFS_CHECK |
2105 | static void tb_buffer_sanity_check(struct super_block *sb, |
2106 | struct buffer_head *bh, |
2107 | const char *descr, int level) |
2108 | { |
2109 | if (bh) { |
2110 | if (atomic_read(&(bh->b_count)) <= 0) |
2111 | |
2112 | reiserfs_panic(sb, "jmacd-1", "negative or zero " |
2113 | "reference counter for buffer %s[%d] " |
2114 | "(%b)", descr, level, bh); |
2115 | |
2116 | if (!buffer_uptodate(bh)) |
2117 | reiserfs_panic(sb, "jmacd-2", "buffer is not up " |
2118 | "to date %s[%d] (%b)", |
2119 | descr, level, bh); |
2120 | |
2121 | if (!B_IS_IN_TREE(bh)) |
2122 | reiserfs_panic(sb, "jmacd-3", "buffer is not " |
2123 | "in tree %s[%d] (%b)", |
2124 | descr, level, bh); |
2125 | |
2126 | if (bh->b_bdev != sb->s_bdev) |
2127 | reiserfs_panic(sb, "jmacd-4", "buffer has wrong " |
2128 | "device %s[%d] (%b)", |
2129 | descr, level, bh); |
2130 | |
2131 | if (bh->b_size != sb->s_blocksize) |
2132 | reiserfs_panic(sb, "jmacd-5", "buffer has wrong " |
2133 | "blocksize %s[%d] (%b)", |
2134 | descr, level, bh); |
2135 | |
2136 | if (bh->b_blocknr > SB_BLOCK_COUNT(sb)) |
2137 | reiserfs_panic(sb, "jmacd-6", "buffer block " |
2138 | "number too high %s[%d] (%b)", |
2139 | descr, level, bh); |
2140 | } |
2141 | } |
2142 | #else |
2143 | static void tb_buffer_sanity_check(struct super_block *sb, |
2144 | struct buffer_head *bh, |
2145 | const char *descr, int level) |
2146 | {; |
2147 | } |
2148 | #endif |
2149 | |
2150 | static int clear_all_dirty_bits(struct super_block *s, struct buffer_head *bh) |
2151 | { |
2152 | return reiserfs_prepare_for_journal(s, bh, 0); |
2153 | } |
2154 | |
2155 | static int wait_tb_buffers_until_unlocked(struct tree_balance *tb) |
2156 | { |
2157 | struct buffer_head *locked; |
2158 | #ifdef CONFIG_REISERFS_CHECK |
2159 | int repeat_counter = 0; |
2160 | #endif |
2161 | int i; |
2162 | |
2163 | do { |
2164 | |
2165 | locked = NULL; |
2166 | |
2167 | for (i = tb->tb_path->path_length; |
2168 | !locked && i > ILLEGAL_PATH_ELEMENT_OFFSET; i--) { |
2169 | if (PATH_OFFSET_PBUFFER(tb->tb_path, i)) { |
2170 | /* if I understand correctly, we can only be sure the last buffer |
2171 | ** in the path is in the tree --clm |
2172 | */ |
2173 | #ifdef CONFIG_REISERFS_CHECK |
2174 | if (PATH_PLAST_BUFFER(tb->tb_path) == |
2175 | PATH_OFFSET_PBUFFER(tb->tb_path, i)) |
2176 | tb_buffer_sanity_check(tb->tb_sb, |
2177 | PATH_OFFSET_PBUFFER |
2178 | (tb->tb_path, |
2179 | i), "S", |
2180 | tb->tb_path-> |
2181 | path_length - i); |
2182 | #endif |
2183 | if (!clear_all_dirty_bits(tb->tb_sb, |
2184 | PATH_OFFSET_PBUFFER |
2185 | (tb->tb_path, |
2186 | i))) { |
2187 | locked = |
2188 | PATH_OFFSET_PBUFFER(tb->tb_path, |
2189 | i); |
2190 | } |
2191 | } |
2192 | } |
2193 | |
2194 | for (i = 0; !locked && i < MAX_HEIGHT && tb->insert_size[i]; |
2195 | i++) { |
2196 | |
2197 | if (tb->lnum[i]) { |
2198 | |
2199 | if (tb->L[i]) { |
2200 | tb_buffer_sanity_check(tb->tb_sb, |
2201 | tb->L[i], |
2202 | "L", i); |
2203 | if (!clear_all_dirty_bits |
2204 | (tb->tb_sb, tb->L[i])) |
2205 | locked = tb->L[i]; |
2206 | } |
2207 | |
2208 | if (!locked && tb->FL[i]) { |
2209 | tb_buffer_sanity_check(tb->tb_sb, |
2210 | tb->FL[i], |
2211 | "FL", i); |
2212 | if (!clear_all_dirty_bits |
2213 | (tb->tb_sb, tb->FL[i])) |
2214 | locked = tb->FL[i]; |
2215 | } |
2216 | |
2217 | if (!locked && tb->CFL[i]) { |
2218 | tb_buffer_sanity_check(tb->tb_sb, |
2219 | tb->CFL[i], |
2220 | "CFL", i); |
2221 | if (!clear_all_dirty_bits |
2222 | (tb->tb_sb, tb->CFL[i])) |
2223 | locked = tb->CFL[i]; |
2224 | } |
2225 | |
2226 | } |
2227 | |
2228 | if (!locked && (tb->rnum[i])) { |
2229 | |
2230 | if (tb->R[i]) { |
2231 | tb_buffer_sanity_check(tb->tb_sb, |
2232 | tb->R[i], |
2233 | "R", i); |
2234 | if (!clear_all_dirty_bits |
2235 | (tb->tb_sb, tb->R[i])) |
2236 | locked = tb->R[i]; |
2237 | } |
2238 | |
2239 | if (!locked && tb->FR[i]) { |
2240 | tb_buffer_sanity_check(tb->tb_sb, |
2241 | tb->FR[i], |
2242 | "FR", i); |
2243 | if (!clear_all_dirty_bits |
2244 | (tb->tb_sb, tb->FR[i])) |
2245 | locked = tb->FR[i]; |
2246 | } |
2247 | |
2248 | if (!locked && tb->CFR[i]) { |
2249 | tb_buffer_sanity_check(tb->tb_sb, |
2250 | tb->CFR[i], |
2251 | "CFR", i); |
2252 | if (!clear_all_dirty_bits |
2253 | (tb->tb_sb, tb->CFR[i])) |
2254 | locked = tb->CFR[i]; |
2255 | } |
2256 | } |
2257 | } |
2258 | /* as far as I can tell, this is not required. The FEB list seems |
2259 | ** to be full of newly allocated nodes, which will never be locked, |
2260 | ** dirty, or anything else. |
2261 | ** To be safe, I'm putting in the checks and waits in. For the moment, |
2262 | ** they are needed to keep the code in journal.c from complaining |
2263 | ** about the buffer. That code is inside CONFIG_REISERFS_CHECK as well. |
2264 | ** --clm |
2265 | */ |
2266 | for (i = 0; !locked && i < MAX_FEB_SIZE; i++) { |
2267 | if (tb->FEB[i]) { |
2268 | if (!clear_all_dirty_bits |
2269 | (tb->tb_sb, tb->FEB[i])) |
2270 | locked = tb->FEB[i]; |
2271 | } |
2272 | } |
2273 | |
2274 | if (locked) { |
2275 | #ifdef CONFIG_REISERFS_CHECK |
2276 | repeat_counter++; |
2277 | if ((repeat_counter % 10000) == 0) { |
2278 | reiserfs_warning(tb->tb_sb, "reiserfs-8200", |
2279 | "too many iterations waiting " |
2280 | "for buffer to unlock " |
2281 | "(%b)", locked); |
2282 | |
2283 | /* Don't loop forever. Try to recover from possible error. */ |
2284 | |
2285 | return (FILESYSTEM_CHANGED_TB(tb)) ? |
2286 | REPEAT_SEARCH : CARRY_ON; |
2287 | } |
2288 | #endif |
2289 | reiserfs_write_unlock(tb->tb_sb); |
2290 | __wait_on_buffer(locked); |
2291 | reiserfs_write_lock(tb->tb_sb); |
2292 | if (FILESYSTEM_CHANGED_TB(tb)) |
2293 | return REPEAT_SEARCH; |
2294 | } |
2295 | |
2296 | } while (locked); |
2297 | |
2298 | return CARRY_ON; |
2299 | } |
2300 | |
2301 | /* Prepare for balancing, that is |
2302 | * get all necessary parents, and neighbors; |
2303 | * analyze what and where should be moved; |
2304 | * get sufficient number of new nodes; |
2305 | * Balancing will start only after all resources will be collected at a time. |
2306 | * |
2307 | * When ported to SMP kernels, only at the last moment after all needed nodes |
2308 | * are collected in cache, will the resources be locked using the usual |
2309 | * textbook ordered lock acquisition algorithms. Note that ensuring that |
2310 | * this code neither write locks what it does not need to write lock nor locks out of order |
2311 | * will be a pain in the butt that could have been avoided. Grumble grumble. -Hans |
2312 | * |
2313 | * fix is meant in the sense of render unchanging |
2314 | * |
2315 | * Latency might be improved by first gathering a list of what buffers are needed |
2316 | * and then getting as many of them in parallel as possible? -Hans |
2317 | * |
2318 | * Parameters: |
2319 | * op_mode i - insert, d - delete, c - cut (truncate), p - paste (append) |
2320 | * tb tree_balance structure; |
2321 | * inum item number in S[h]; |
2322 | * pos_in_item - comment this if you can |
2323 | * ins_ih item head of item being inserted |
2324 | * data inserted item or data to be pasted |
2325 | * Returns: 1 - schedule occurred while the function worked; |
2326 | * 0 - schedule didn't occur while the function worked; |
2327 | * -1 - if no_disk_space |
2328 | */ |
2329 | |
2330 | int fix_nodes(int op_mode, struct tree_balance *tb, |
2331 | struct item_head *ins_ih, const void *data) |
2332 | { |
2333 | int ret, h, item_num = PATH_LAST_POSITION(tb->tb_path); |
2334 | int pos_in_item; |
2335 | |
2336 | /* we set wait_tb_buffers_run when we have to restore any dirty bits cleared |
2337 | ** during wait_tb_buffers_run |
2338 | */ |
2339 | int wait_tb_buffers_run = 0; |
2340 | struct buffer_head *tbS0 = PATH_PLAST_BUFFER(tb->tb_path); |
2341 | |
2342 | ++REISERFS_SB(tb->tb_sb)->s_fix_nodes; |
2343 | |
2344 | pos_in_item = tb->tb_path->pos_in_item; |
2345 | |
2346 | tb->fs_gen = get_generation(tb->tb_sb); |
2347 | |
2348 | /* we prepare and log the super here so it will already be in the |
2349 | ** transaction when do_balance needs to change it. |
2350 | ** This way do_balance won't have to schedule when trying to prepare |
2351 | ** the super for logging |
2352 | */ |
2353 | reiserfs_prepare_for_journal(tb->tb_sb, |
2354 | SB_BUFFER_WITH_SB(tb->tb_sb), 1); |
2355 | journal_mark_dirty(tb->transaction_handle, tb->tb_sb, |
2356 | SB_BUFFER_WITH_SB(tb->tb_sb)); |
2357 | if (FILESYSTEM_CHANGED_TB(tb)) |
2358 | return REPEAT_SEARCH; |
2359 | |
2360 | /* if it possible in indirect_to_direct conversion */ |
2361 | if (buffer_locked(tbS0)) { |
2362 | reiserfs_write_unlock(tb->tb_sb); |
2363 | __wait_on_buffer(tbS0); |
2364 | reiserfs_write_lock(tb->tb_sb); |
2365 | if (FILESYSTEM_CHANGED_TB(tb)) |
2366 | return REPEAT_SEARCH; |
2367 | } |
2368 | #ifdef CONFIG_REISERFS_CHECK |
2369 | if (REISERFS_SB(tb->tb_sb)->cur_tb) { |
2370 | print_cur_tb("fix_nodes"); |
2371 | reiserfs_panic(tb->tb_sb, "PAP-8305", |
2372 | "there is pending do_balance"); |
2373 | } |
2374 | |
2375 | if (!buffer_uptodate(tbS0) || !B_IS_IN_TREE(tbS0)) |
2376 | reiserfs_panic(tb->tb_sb, "PAP-8320", "S[0] (%b %z) is " |
2377 | "not uptodate at the beginning of fix_nodes " |
2378 | "or not in tree (mode %c)", |
2379 | tbS0, tbS0, op_mode); |
2380 | |
2381 | /* Check parameters. */ |
2382 | switch (op_mode) { |
2383 | case M_INSERT: |
2384 | if (item_num <= 0 || item_num > B_NR_ITEMS(tbS0)) |
2385 | reiserfs_panic(tb->tb_sb, "PAP-8330", "Incorrect " |
2386 | "item number %d (in S0 - %d) in case " |
2387 | "of insert", item_num, |
2388 | B_NR_ITEMS(tbS0)); |
2389 | break; |
2390 | case M_PASTE: |
2391 | case M_DELETE: |
2392 | case M_CUT: |
2393 | if (item_num < 0 || item_num >= B_NR_ITEMS(tbS0)) { |
2394 | print_block(tbS0, 0, -1, -1); |
2395 | reiserfs_panic(tb->tb_sb, "PAP-8335", "Incorrect " |
2396 | "item number(%d); mode = %c " |
2397 | "insert_size = %d", |
2398 | item_num, op_mode, |
2399 | tb->insert_size[0]); |
2400 | } |
2401 | break; |
2402 | default: |
2403 | reiserfs_panic(tb->tb_sb, "PAP-8340", "Incorrect mode " |
2404 | "of operation"); |
2405 | } |
2406 | #endif |
2407 | |
2408 | if (get_mem_for_virtual_node(tb) == REPEAT_SEARCH) |
2409 | // FIXME: maybe -ENOMEM when tb->vn_buf == 0? Now just repeat |
2410 | return REPEAT_SEARCH; |
2411 | |
2412 | /* Starting from the leaf level; for all levels h of the tree. */ |
2413 | for (h = 0; h < MAX_HEIGHT && tb->insert_size[h]; h++) { |
2414 | ret = get_direct_parent(tb, h); |
2415 | if (ret != CARRY_ON) |
2416 | goto repeat; |
2417 | |
2418 | ret = check_balance(op_mode, tb, h, item_num, |
2419 | pos_in_item, ins_ih, data); |
2420 | if (ret != CARRY_ON) { |
2421 | if (ret == NO_BALANCING_NEEDED) { |
2422 | /* No balancing for higher levels needed. */ |
2423 | ret = get_neighbors(tb, h); |
2424 | if (ret != CARRY_ON) |
2425 | goto repeat; |
2426 | if (h != MAX_HEIGHT - 1) |
2427 | tb->insert_size[h + 1] = 0; |
2428 | /* ok, analysis and resource gathering are complete */ |
2429 | break; |
2430 | } |
2431 | goto repeat; |
2432 | } |
2433 | |
2434 | ret = get_neighbors(tb, h); |
2435 | if (ret != CARRY_ON) |
2436 | goto repeat; |
2437 | |
2438 | /* No disk space, or schedule occurred and analysis may be |
2439 | * invalid and needs to be redone. */ |
2440 | ret = get_empty_nodes(tb, h); |
2441 | if (ret != CARRY_ON) |
2442 | goto repeat; |
2443 | |
2444 | if (!PATH_H_PBUFFER(tb->tb_path, h)) { |
2445 | /* We have a positive insert size but no nodes exist on this |
2446 | level, this means that we are creating a new root. */ |
2447 | |
2448 | RFALSE(tb->blknum[h] != 1, |
2449 | "PAP-8350: creating new empty root"); |
2450 | |
2451 | if (h < MAX_HEIGHT - 1) |
2452 | tb->insert_size[h + 1] = 0; |
2453 | } else if (!PATH_H_PBUFFER(tb->tb_path, h + 1)) { |
2454 | if (tb->blknum[h] > 1) { |
2455 | /* The tree needs to be grown, so this node S[h] |
2456 | which is the root node is split into two nodes, |
2457 | and a new node (S[h+1]) will be created to |
2458 | become the root node. */ |
2459 | |
2460 | RFALSE(h == MAX_HEIGHT - 1, |
2461 | "PAP-8355: attempt to create too high of a tree"); |
2462 | |
2463 | tb->insert_size[h + 1] = |
2464 | (DC_SIZE + |
2465 | KEY_SIZE) * (tb->blknum[h] - 1) + |
2466 | DC_SIZE; |
2467 | } else if (h < MAX_HEIGHT - 1) |
2468 | tb->insert_size[h + 1] = 0; |
2469 | } else |
2470 | tb->insert_size[h + 1] = |
2471 | (DC_SIZE + KEY_SIZE) * (tb->blknum[h] - 1); |
2472 | } |
2473 | |
2474 | ret = wait_tb_buffers_until_unlocked(tb); |
2475 | if (ret == CARRY_ON) { |
2476 | if (FILESYSTEM_CHANGED_TB(tb)) { |
2477 | wait_tb_buffers_run = 1; |
2478 | ret = REPEAT_SEARCH; |
2479 | goto repeat; |
2480 | } else { |
2481 | return CARRY_ON; |
2482 | } |
2483 | } else { |
2484 | wait_tb_buffers_run = 1; |
2485 | goto repeat; |
2486 | } |
2487 | |
2488 | repeat: |
2489 | // fix_nodes was unable to perform its calculation due to |
2490 | // filesystem got changed under us, lack of free disk space or i/o |
2491 | // failure. If the first is the case - the search will be |
2492 | // repeated. For now - free all resources acquired so far except |
2493 | // for the new allocated nodes |
2494 | { |
2495 | int i; |
2496 | |
2497 | /* Release path buffers. */ |
2498 | if (wait_tb_buffers_run) { |
2499 | pathrelse_and_restore(tb->tb_sb, tb->tb_path); |
2500 | } else { |
2501 | pathrelse(tb->tb_path); |
2502 | } |
2503 | /* brelse all resources collected for balancing */ |
2504 | for (i = 0; i < MAX_HEIGHT; i++) { |
2505 | if (wait_tb_buffers_run) { |
2506 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2507 | tb->L[i]); |
2508 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2509 | tb->R[i]); |
2510 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2511 | tb->FL[i]); |
2512 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2513 | tb->FR[i]); |
2514 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2515 | tb-> |
2516 | CFL[i]); |
2517 | reiserfs_restore_prepared_buffer(tb->tb_sb, |
2518 | tb-> |
2519 | CFR[i]); |
2520 | } |
2521 | |
2522 | brelse(tb->L[i]); |
2523 | brelse(tb->R[i]); |
2524 | brelse(tb->FL[i]); |
2525 | brelse(tb->FR[i]); |
2526 | brelse(tb->CFL[i]); |
2527 | brelse(tb->CFR[i]); |
2528 | |
2529 | tb->L[i] = NULL; |
2530 | tb->R[i] = NULL; |
2531 | tb->FL[i] = NULL; |
2532 | tb->FR[i] = NULL; |
2533 | tb->CFL[i] = NULL; |
2534 | tb->CFR[i] = NULL; |
2535 | } |
2536 | |
2537 | if (wait_tb_buffers_run) { |
2538 | for (i = 0; i < MAX_FEB_SIZE; i++) { |
2539 | if (tb->FEB[i]) |
2540 | reiserfs_restore_prepared_buffer |
2541 | (tb->tb_sb, tb->FEB[i]); |
2542 | } |
2543 | } |
2544 | return ret; |
2545 | } |
2546 | |
2547 | } |
2548 | |
2549 | /* Anatoly will probably forgive me renaming tb to tb. I just |
2550 | wanted to make lines shorter */ |
2551 | void unfix_nodes(struct tree_balance *tb) |
2552 | { |
2553 | int i; |
2554 | |
2555 | /* Release path buffers. */ |
2556 | pathrelse_and_restore(tb->tb_sb, tb->tb_path); |
2557 | |
2558 | /* brelse all resources collected for balancing */ |
2559 | for (i = 0; i < MAX_HEIGHT; i++) { |
2560 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->L[i]); |
2561 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->R[i]); |
2562 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FL[i]); |
2563 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FR[i]); |
2564 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFL[i]); |
2565 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFR[i]); |
2566 | |
2567 | brelse(tb->L[i]); |
2568 | brelse(tb->R[i]); |
2569 | brelse(tb->FL[i]); |
2570 | brelse(tb->FR[i]); |
2571 | brelse(tb->CFL[i]); |
2572 | brelse(tb->CFR[i]); |
2573 | } |
2574 | |
2575 | /* deal with list of allocated (used and unused) nodes */ |
2576 | for (i = 0; i < MAX_FEB_SIZE; i++) { |
2577 | if (tb->FEB[i]) { |
2578 | b_blocknr_t blocknr = tb->FEB[i]->b_blocknr; |
2579 | /* de-allocated block which was not used by balancing and |
2580 | bforget about buffer for it */ |
2581 | brelse(tb->FEB[i]); |
2582 | reiserfs_free_block(tb->transaction_handle, NULL, |
2583 | blocknr, 0); |
2584 | } |
2585 | if (tb->used[i]) { |
2586 | /* release used as new nodes including a new root */ |
2587 | brelse(tb->used[i]); |
2588 | } |
2589 | } |
2590 | |
2591 | kfree(tb->vn_buf); |
2592 | |
2593 | } |
2594 |
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