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1da177e4 LT |
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 | ||
1da177e4 LT |
37 | #include <linux/config.h> |
38 | #include <linux/time.h> | |
39 | #include <linux/string.h> | |
40 | #include <linux/reiserfs_fs.h> | |
41 | #include <linux/buffer_head.h> | |
42 | ||
1da177e4 LT |
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 | ||
1da177e4 | 57 | /* taking item number in virtual node, returns number of item, that it has in source buffer */ |
bd4c625c | 58 | static inline int old_item_num(int new_num, int affected_item_num, int mode) |
1da177e4 | 59 | { |
bd4c625c LT |
60 | if (mode == M_PASTE || mode == M_CUT || new_num < affected_item_num) |
61 | return new_num; | |
1da177e4 | 62 | |
bd4c625c | 63 | if (mode == M_INSERT) { |
1da177e4 | 64 | |
bd4c625c LT |
65 | RFALSE(new_num == 0, |
66 | "vs-8005: for INSERT mode and item number of inserted item"); | |
1da177e4 | 67 | |
bd4c625c LT |
68 | return new_num - 1; |
69 | } | |
1da177e4 | 70 | |
bd4c625c LT |
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; | |
1da177e4 LT |
76 | } |
77 | ||
bd4c625c | 78 | static void create_virtual_node(struct tree_balance *tb, int h) |
1da177e4 | 79 | { |
bd4c625c LT |
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] */ | |
1da177e4 | 84 | |
bd4c625c | 85 | Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1da177e4 | 86 | |
bd4c625c LT |
87 | /* size of changed node */ |
88 | vn->vn_size = | |
89 | MAX_CHILD_SIZE(Sh) - B_FREE_SPACE(Sh) + tb->insert_size[h]; | |
1da177e4 | 90 | |
bd4c625c LT |
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; | |
1da177e4 | 95 | } |
1da177e4 | 96 | |
bd4c625c LT |
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, | |
140 | "vs-8030: create_virtual_node: " | |
141 | "virtual node space consumed"); | |
142 | ||
143 | if (!is_affected) | |
144 | /* this is not being changed */ | |
145 | continue; | |
146 | ||
147 | if (vn->vn_mode == M_PASTE || vn->vn_mode == M_CUT) { | |
148 | vn->vn_vi[new_num].vi_item_len += tb->insert_size[0]; | |
149 | vi->vi_new_data = vn->vn_data; // pointer to data which is going to be pasted | |
150 | } | |
1da177e4 | 151 | } |
bd4c625c LT |
152 | |
153 | /* virtual inserted item is not defined yet */ | |
154 | if (vn->vn_mode == M_INSERT) { | |
155 | struct virtual_item *vi = vn->vn_vi + vn->vn_affected_item_num; | |
156 | ||
157 | RFALSE(vn->vn_ins_ih == 0, | |
158 | "vs-8040: item header of inserted item is not specified"); | |
159 | vi->vi_item_len = tb->insert_size[0]; | |
160 | vi->vi_ih = vn->vn_ins_ih; | |
161 | vi->vi_item = vn->vn_data; | |
162 | vi->vi_uarea = vn->vn_free_ptr; | |
163 | ||
164 | op_create_vi(vn, vi, 0 /*not pasted or cut */ , | |
165 | tb->insert_size[0]); | |
166 | } | |
167 | ||
168 | /* set right merge flag we take right delimiting key and check whether it is a mergeable item */ | |
169 | if (tb->CFR[0]) { | |
170 | struct reiserfs_key *key; | |
171 | ||
172 | key = B_N_PDELIM_KEY(tb->CFR[0], tb->rkey[0]); | |
173 | if (op_is_left_mergeable(key, Sh->b_size) | |
174 | && (vn->vn_mode != M_DELETE | |
175 | || vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) | |
176 | vn->vn_vi[vn->vn_nr_item - 1].vi_type |= | |
177 | VI_TYPE_RIGHT_MERGEABLE; | |
178 | ||
179 | #ifdef CONFIG_REISERFS_CHECK | |
180 | if (op_is_left_mergeable(key, Sh->b_size) && | |
181 | !(vn->vn_mode != M_DELETE | |
182 | || vn->vn_affected_item_num != B_NR_ITEMS(Sh) - 1)) { | |
183 | /* we delete last item and it could be merged with right neighbor's first item */ | |
184 | if (! | |
185 | (B_NR_ITEMS(Sh) == 1 | |
186 | && is_direntry_le_ih(B_N_PITEM_HEAD(Sh, 0)) | |
187 | && I_ENTRY_COUNT(B_N_PITEM_HEAD(Sh, 0)) == 1)) { | |
188 | /* node contains more than 1 item, or item is not directory item, or this item contains more than 1 entry */ | |
189 | print_block(Sh, 0, -1, -1); | |
190 | reiserfs_panic(tb->tb_sb, | |
191 | "vs-8045: create_virtual_node: rdkey %k, affected item==%d (mode==%c) Must be %c", | |
192 | key, vn->vn_affected_item_num, | |
193 | vn->vn_mode, M_DELETE); | |
cd02b966 | 194 | } |
bd4c625c | 195 | } |
1da177e4 | 196 | #endif |
1da177e4 | 197 | |
bd4c625c LT |
198 | } |
199 | } | |
1da177e4 LT |
200 | |
201 | /* using virtual node check, how many items can be shifted to left | |
202 | neighbor */ | |
bd4c625c | 203 | static void check_left(struct tree_balance *tb, int h, int cur_free) |
1da177e4 | 204 | { |
bd4c625c LT |
205 | int i; |
206 | struct virtual_node *vn = tb->tb_vn; | |
207 | struct virtual_item *vi; | |
208 | int d_size, ih_size; | |
1da177e4 | 209 | |
bd4c625c | 210 | RFALSE(cur_free < 0, "vs-8050: cur_free (%d) < 0", cur_free); |
1da177e4 | 211 | |
bd4c625c LT |
212 | /* internal level */ |
213 | if (h > 0) { | |
214 | tb->lnum[h] = cur_free / (DC_SIZE + KEY_SIZE); | |
215 | return; | |
216 | } | |
1da177e4 | 217 | |
bd4c625c | 218 | /* leaf level */ |
1da177e4 | 219 | |
bd4c625c LT |
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 | } | |
1da177e4 | 226 | |
bd4c625c LT |
227 | RFALSE(!PATH_H_PPARENT(tb->tb_path, 0), |
228 | "vs-8055: parent does not exist or invalid"); | |
1da177e4 | 229 | |
bd4c625c LT |
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] */ | |
1da177e4 | 235 | |
bd4c625c LT |
236 | RFALSE(vn->vn_mode == M_INSERT || vn->vn_mode == M_PASTE, |
237 | "vs-8055: invalid mode or balance condition failed"); | |
1da177e4 | 238 | |
bd4c625c LT |
239 | tb->lnum[0] = vn->vn_nr_item; |
240 | tb->lbytes = -1; | |
241 | return; | |
1da177e4 | 242 | } |
bd4c625c LT |
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; | |
1da177e4 | 276 | } |
1da177e4 | 277 | |
bd4c625c LT |
278 | return; |
279 | } | |
1da177e4 LT |
280 | |
281 | /* using virtual node check, how many items can be shifted to right | |
282 | neighbor */ | |
bd4c625c | 283 | static void check_right(struct tree_balance *tb, int h, int cur_free) |
1da177e4 | 284 | { |
bd4c625c LT |
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; | |
1da177e4 | 296 | } |
bd4c625c LT |
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; | |
1da177e4 | 305 | } |
1da177e4 | 306 | |
bd4c625c LT |
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 | } | |
1da177e4 LT |
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 */ | |
bd4c625c LT |
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) | |
1da177e4 | 369 | { |
bd4c625c LT |
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); | |
1da177e4 LT |
412 | } |
413 | ||
bd4c625c LT |
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: get_num_ver: " | |
501 | "split_item_position is out of boundary"); | |
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; | |
1da177e4 LT |
509 | } |
510 | ||
bd4c625c LT |
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: get_num_ver: not " | |
538 | "directory or indirect item"); | |
1da177e4 LT |
539 | } |
540 | ||
bd4c625c LT |
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; | |
1da177e4 LT |
562 | } |
563 | ||
bd4c625c | 564 | return needed_nodes; |
1da177e4 LT |
565 | } |
566 | ||
1da177e4 | 567 | #ifdef CONFIG_REISERFS_CHECK |
bd4c625c | 568 | extern struct tree_balance *cur_tb; |
1da177e4 LT |
569 | #endif |
570 | ||
1da177e4 LT |
571 | /* Set parameters for balancing. |
572 | * Performs write of results of analysis of balancing into structure tb, | |
573 | * where it will later be used by the functions that actually do the balancing. | |
574 | * Parameters: | |
575 | * tb tree_balance structure; | |
576 | * h current level of the node; | |
577 | * lnum number of items from S[h] that must be shifted to L[h]; | |
578 | * rnum number of items from S[h] that must be shifted to R[h]; | |
579 | * blk_num number of blocks that S[h] will be splitted into; | |
580 | * s012 number of items that fall into splitted nodes. | |
581 | * lbytes number of bytes which flow to the left neighbor from the item that is not | |
582 | * not shifted entirely | |
583 | * rbytes number of bytes which flow to the right neighbor from the item that is not | |
584 | * not shifted entirely | |
585 | * s1bytes number of bytes which flow to the first new node when S[0] splits (this number is contained in s012 array) | |
586 | */ | |
587 | ||
bd4c625c LT |
588 | static void set_parameters(struct tree_balance *tb, int h, int lnum, |
589 | int rnum, int blk_num, short *s012, int lb, int rb) | |
1da177e4 LT |
590 | { |
591 | ||
bd4c625c LT |
592 | tb->lnum[h] = lnum; |
593 | tb->rnum[h] = rnum; | |
594 | tb->blknum[h] = blk_num; | |
1da177e4 | 595 | |
bd4c625c LT |
596 | if (h == 0) { /* only for leaf level */ |
597 | if (s012 != NULL) { | |
598 | tb->s0num = *s012++, | |
599 | tb->s1num = *s012++, tb->s2num = *s012++; | |
600 | tb->s1bytes = *s012++; | |
601 | tb->s2bytes = *s012; | |
602 | } | |
603 | tb->lbytes = lb; | |
604 | tb->rbytes = rb; | |
1da177e4 | 605 | } |
bd4c625c LT |
606 | PROC_INFO_ADD(tb->tb_sb, lnum[h], lnum); |
607 | PROC_INFO_ADD(tb->tb_sb, rnum[h], rnum); | |
1da177e4 | 608 | |
bd4c625c LT |
609 | PROC_INFO_ADD(tb->tb_sb, lbytes[h], lb); |
610 | PROC_INFO_ADD(tb->tb_sb, rbytes[h], rb); | |
611 | } | |
1da177e4 LT |
612 | |
613 | /* check, does node disappear if we shift tb->lnum[0] items to left | |
614 | neighbor and tb->rnum[0] to the right one. */ | |
bd4c625c | 615 | static int is_leaf_removable(struct tree_balance *tb) |
1da177e4 | 616 | { |
bd4c625c LT |
617 | struct virtual_node *vn = tb->tb_vn; |
618 | int to_left, to_right; | |
619 | int size; | |
620 | int remain_items; | |
621 | ||
622 | /* number of items, that will be shifted to left (right) neighbor | |
623 | entirely */ | |
624 | to_left = tb->lnum[0] - ((tb->lbytes != -1) ? 1 : 0); | |
625 | to_right = tb->rnum[0] - ((tb->rbytes != -1) ? 1 : 0); | |
626 | remain_items = vn->vn_nr_item; | |
627 | ||
628 | /* how many items remain in S[0] after shiftings to neighbors */ | |
629 | remain_items -= (to_left + to_right); | |
630 | ||
631 | if (remain_items < 1) { | |
632 | /* all content of node can be shifted to neighbors */ | |
633 | set_parameters(tb, 0, to_left, vn->vn_nr_item - to_left, 0, | |
634 | NULL, -1, -1); | |
635 | return 1; | |
636 | } | |
1da177e4 | 637 | |
bd4c625c LT |
638 | if (remain_items > 1 || tb->lbytes == -1 || tb->rbytes == -1) |
639 | /* S[0] is not removable */ | |
640 | return 0; | |
641 | ||
642 | /* check, whether we can divide 1 remaining item between neighbors */ | |
643 | ||
644 | /* get size of remaining item (in item units) */ | |
645 | size = op_unit_num(&(vn->vn_vi[to_left])); | |
646 | ||
647 | if (tb->lbytes + tb->rbytes >= size) { | |
648 | set_parameters(tb, 0, to_left + 1, to_right + 1, 0, NULL, | |
649 | tb->lbytes, -1); | |
650 | return 1; | |
651 | } | |
652 | ||
653 | return 0; | |
654 | } | |
1da177e4 LT |
655 | |
656 | /* check whether L, S, R can be joined in one node */ | |
bd4c625c | 657 | static int are_leaves_removable(struct tree_balance *tb, int lfree, int rfree) |
1da177e4 | 658 | { |
bd4c625c LT |
659 | struct virtual_node *vn = tb->tb_vn; |
660 | int ih_size; | |
661 | struct buffer_head *S0; | |
662 | ||
663 | S0 = PATH_H_PBUFFER(tb->tb_path, 0); | |
664 | ||
665 | ih_size = 0; | |
666 | if (vn->vn_nr_item) { | |
667 | if (vn->vn_vi[0].vi_type & VI_TYPE_LEFT_MERGEABLE) | |
668 | ih_size += IH_SIZE; | |
669 | ||
670 | if (vn->vn_vi[vn->vn_nr_item - 1]. | |
671 | vi_type & VI_TYPE_RIGHT_MERGEABLE) | |
672 | ih_size += IH_SIZE; | |
673 | } else { | |
674 | /* there was only one item and it will be deleted */ | |
675 | struct item_head *ih; | |
676 | ||
677 | RFALSE(B_NR_ITEMS(S0) != 1, | |
678 | "vs-8125: item number must be 1: it is %d", | |
679 | B_NR_ITEMS(S0)); | |
680 | ||
681 | ih = B_N_PITEM_HEAD(S0, 0); | |
682 | if (tb->CFR[0] | |
683 | && !comp_short_le_keys(&(ih->ih_key), | |
684 | B_N_PDELIM_KEY(tb->CFR[0], | |
685 | tb->rkey[0]))) | |
686 | if (is_direntry_le_ih(ih)) { | |
687 | /* Directory must be in correct state here: that is | |
688 | somewhere at the left side should exist first directory | |
689 | item. But the item being deleted can not be that first | |
690 | one because its right neighbor is item of the same | |
691 | directory. (But first item always gets deleted in last | |
692 | turn). So, neighbors of deleted item can be merged, so | |
693 | we can save ih_size */ | |
694 | ih_size = IH_SIZE; | |
695 | ||
696 | /* we might check that left neighbor exists and is of the | |
697 | same directory */ | |
698 | RFALSE(le_ih_k_offset(ih) == DOT_OFFSET, | |
699 | "vs-8130: first directory item can not be removed until directory is not empty"); | |
700 | } | |
1da177e4 | 701 | |
bd4c625c LT |
702 | } |
703 | ||
704 | if (MAX_CHILD_SIZE(S0) + vn->vn_size <= rfree + lfree + ih_size) { | |
705 | set_parameters(tb, 0, -1, -1, -1, NULL, -1, -1); | |
706 | PROC_INFO_INC(tb->tb_sb, leaves_removable); | |
707 | return 1; | |
708 | } | |
709 | return 0; | |
1da177e4 | 710 | |
bd4c625c | 711 | } |
1da177e4 LT |
712 | |
713 | /* when we do not split item, lnum and rnum are numbers of entire items */ | |
714 | #define SET_PAR_SHIFT_LEFT \ | |
715 | if (h)\ | |
716 | {\ | |
717 | int to_l;\ | |
718 | \ | |
719 | to_l = (MAX_NR_KEY(Sh)+1 - lpar + vn->vn_nr_item + 1) / 2 -\ | |
720 | (MAX_NR_KEY(Sh) + 1 - lpar);\ | |
721 | \ | |
722 | set_parameters (tb, h, to_l, 0, lnver, NULL, -1, -1);\ | |
723 | }\ | |
724 | else \ | |
725 | {\ | |
726 | if (lset==LEFT_SHIFT_FLOW)\ | |
727 | set_parameters (tb, h, lpar, 0, lnver, snum012+lset,\ | |
728 | tb->lbytes, -1);\ | |
729 | else\ | |
730 | set_parameters (tb, h, lpar - (tb->lbytes!=-1), 0, lnver, snum012+lset,\ | |
731 | -1, -1);\ | |
732 | } | |
733 | ||
1da177e4 LT |
734 | #define SET_PAR_SHIFT_RIGHT \ |
735 | if (h)\ | |
736 | {\ | |
737 | int to_r;\ | |
738 | \ | |
739 | to_r = (MAX_NR_KEY(Sh)+1 - rpar + vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - rpar);\ | |
740 | \ | |
741 | set_parameters (tb, h, 0, to_r, rnver, NULL, -1, -1);\ | |
742 | }\ | |
743 | else \ | |
744 | {\ | |
745 | if (rset==RIGHT_SHIFT_FLOW)\ | |
746 | set_parameters (tb, h, 0, rpar, rnver, snum012+rset,\ | |
747 | -1, tb->rbytes);\ | |
748 | else\ | |
749 | set_parameters (tb, h, 0, rpar - (tb->rbytes!=-1), rnver, snum012+rset,\ | |
750 | -1, -1);\ | |
751 | } | |
752 | ||
bd4c625c LT |
753 | static void free_buffers_in_tb(struct tree_balance *p_s_tb) |
754 | { | |
755 | int n_counter; | |
756 | ||
757 | decrement_counters_in_path(p_s_tb->tb_path); | |
758 | ||
759 | for (n_counter = 0; n_counter < MAX_HEIGHT; n_counter++) { | |
760 | decrement_bcount(p_s_tb->L[n_counter]); | |
761 | p_s_tb->L[n_counter] = NULL; | |
762 | decrement_bcount(p_s_tb->R[n_counter]); | |
763 | p_s_tb->R[n_counter] = NULL; | |
764 | decrement_bcount(p_s_tb->FL[n_counter]); | |
765 | p_s_tb->FL[n_counter] = NULL; | |
766 | decrement_bcount(p_s_tb->FR[n_counter]); | |
767 | p_s_tb->FR[n_counter] = NULL; | |
768 | decrement_bcount(p_s_tb->CFL[n_counter]); | |
769 | p_s_tb->CFL[n_counter] = NULL; | |
770 | decrement_bcount(p_s_tb->CFR[n_counter]); | |
771 | p_s_tb->CFR[n_counter] = NULL; | |
772 | } | |
1da177e4 LT |
773 | } |
774 | ||
1da177e4 LT |
775 | /* Get new buffers for storing new nodes that are created while balancing. |
776 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; | |
777 | * CARRY_ON - schedule didn't occur while the function worked; | |
778 | * NO_DISK_SPACE - no disk space. | |
779 | */ | |
780 | /* The function is NOT SCHEDULE-SAFE! */ | |
bd4c625c LT |
781 | static int get_empty_nodes(struct tree_balance *p_s_tb, int n_h) |
782 | { | |
783 | struct buffer_head *p_s_new_bh, | |
784 | *p_s_Sh = PATH_H_PBUFFER(p_s_tb->tb_path, n_h); | |
785 | b_blocknr_t *p_n_blocknr, a_n_blocknrs[MAX_AMOUNT_NEEDED] = { 0, }; | |
786 | int n_counter, n_number_of_freeblk, n_amount_needed, /* number of needed empty blocks */ | |
787 | n_retval = CARRY_ON; | |
788 | struct super_block *p_s_sb = p_s_tb->tb_sb; | |
789 | ||
790 | /* number_of_freeblk is the number of empty blocks which have been | |
791 | acquired for use by the balancing algorithm minus the number of | |
792 | empty blocks used in the previous levels of the analysis, | |
793 | number_of_freeblk = tb->cur_blknum can be non-zero if a schedule occurs | |
794 | after empty blocks are acquired, and the balancing analysis is | |
795 | then restarted, amount_needed is the number needed by this level | |
796 | (n_h) of the balancing analysis. | |
797 | ||
798 | Note that for systems with many processes writing, it would be | |
799 | more layout optimal to calculate the total number needed by all | |
800 | levels and then to run reiserfs_new_blocks to get all of them at once. */ | |
801 | ||
802 | /* Initiate number_of_freeblk to the amount acquired prior to the restart of | |
803 | the analysis or 0 if not restarted, then subtract the amount needed | |
804 | by all of the levels of the tree below n_h. */ | |
805 | /* blknum includes S[n_h], so we subtract 1 in this calculation */ | |
806 | for (n_counter = 0, n_number_of_freeblk = p_s_tb->cur_blknum; | |
807 | n_counter < n_h; n_counter++) | |
808 | n_number_of_freeblk -= | |
809 | (p_s_tb->blknum[n_counter]) ? (p_s_tb->blknum[n_counter] - | |
810 | 1) : 0; | |
811 | ||
812 | /* Allocate missing empty blocks. */ | |
813 | /* if p_s_Sh == 0 then we are getting a new root */ | |
814 | n_amount_needed = (p_s_Sh) ? (p_s_tb->blknum[n_h] - 1) : 1; | |
815 | /* Amount_needed = the amount that we need more than the amount that we have. */ | |
816 | if (n_amount_needed > n_number_of_freeblk) | |
817 | n_amount_needed -= n_number_of_freeblk; | |
818 | else /* If we have enough already then there is nothing to do. */ | |
819 | return CARRY_ON; | |
820 | ||
821 | /* No need to check quota - is not allocated for blocks used for formatted nodes */ | |
822 | if (reiserfs_new_form_blocknrs(p_s_tb, a_n_blocknrs, | |
823 | n_amount_needed) == NO_DISK_SPACE) | |
824 | return NO_DISK_SPACE; | |
825 | ||
826 | /* for each blocknumber we just got, get a buffer and stick it on FEB */ | |
827 | for (p_n_blocknr = a_n_blocknrs, n_counter = 0; | |
828 | n_counter < n_amount_needed; p_n_blocknr++, n_counter++) { | |
829 | ||
830 | RFALSE(!*p_n_blocknr, | |
831 | "PAP-8135: reiserfs_new_blocknrs failed when got new blocks"); | |
832 | ||
833 | p_s_new_bh = sb_getblk(p_s_sb, *p_n_blocknr); | |
834 | RFALSE(buffer_dirty(p_s_new_bh) || | |
835 | buffer_journaled(p_s_new_bh) || | |
836 | buffer_journal_dirty(p_s_new_bh), | |
837 | "PAP-8140: journlaled or dirty buffer %b for the new block", | |
838 | p_s_new_bh); | |
839 | ||
840 | /* Put empty buffers into the array. */ | |
841 | RFALSE(p_s_tb->FEB[p_s_tb->cur_blknum], | |
842 | "PAP-8141: busy slot for new buffer"); | |
843 | ||
844 | set_buffer_journal_new(p_s_new_bh); | |
845 | p_s_tb->FEB[p_s_tb->cur_blknum++] = p_s_new_bh; | |
846 | } | |
847 | ||
848 | if (n_retval == CARRY_ON && FILESYSTEM_CHANGED_TB(p_s_tb)) | |
849 | n_retval = REPEAT_SEARCH; | |
1da177e4 | 850 | |
bd4c625c LT |
851 | return n_retval; |
852 | } | |
1da177e4 LT |
853 | |
854 | /* Get free space of the left neighbor, which is stored in the parent | |
855 | * node of the left neighbor. */ | |
bd4c625c | 856 | static int get_lfree(struct tree_balance *tb, int h) |
1da177e4 | 857 | { |
bd4c625c LT |
858 | struct buffer_head *l, *f; |
859 | int order; | |
1da177e4 | 860 | |
bd4c625c LT |
861 | if ((f = PATH_H_PPARENT(tb->tb_path, h)) == 0 || (l = tb->FL[h]) == 0) |
862 | return 0; | |
1da177e4 | 863 | |
bd4c625c LT |
864 | if (f == l) |
865 | order = PATH_H_B_ITEM_ORDER(tb->tb_path, h) - 1; | |
866 | else { | |
867 | order = B_NR_ITEMS(l); | |
868 | f = l; | |
869 | } | |
1da177e4 | 870 | |
bd4c625c | 871 | return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order))); |
1da177e4 LT |
872 | } |
873 | ||
1da177e4 LT |
874 | /* Get free space of the right neighbor, |
875 | * which is stored in the parent node of the right neighbor. | |
876 | */ | |
bd4c625c | 877 | static int get_rfree(struct tree_balance *tb, int h) |
1da177e4 | 878 | { |
bd4c625c LT |
879 | struct buffer_head *r, *f; |
880 | int order; | |
1da177e4 | 881 | |
bd4c625c LT |
882 | if ((f = PATH_H_PPARENT(tb->tb_path, h)) == 0 || (r = tb->FR[h]) == 0) |
883 | return 0; | |
1da177e4 | 884 | |
bd4c625c LT |
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 | } | |
1da177e4 | 891 | |
bd4c625c | 892 | return (MAX_CHILD_SIZE(f) - dc_size(B_N_CHILD(f, order))); |
1da177e4 LT |
893 | |
894 | } | |
895 | ||
1da177e4 | 896 | /* Check whether left neighbor is in memory. */ |
bd4c625c LT |
897 | static int is_left_neighbor_in_cache(struct tree_balance *p_s_tb, int n_h) |
898 | { | |
899 | struct buffer_head *p_s_father, *left; | |
900 | struct super_block *p_s_sb = p_s_tb->tb_sb; | |
901 | b_blocknr_t n_left_neighbor_blocknr; | |
902 | int n_left_neighbor_position; | |
903 | ||
904 | if (!p_s_tb->FL[n_h]) /* Father of the left neighbor does not exist. */ | |
905 | return 0; | |
906 | ||
907 | /* Calculate father of the node to be balanced. */ | |
908 | p_s_father = PATH_H_PBUFFER(p_s_tb->tb_path, n_h + 1); | |
909 | ||
910 | RFALSE(!p_s_father || | |
911 | !B_IS_IN_TREE(p_s_father) || | |
912 | !B_IS_IN_TREE(p_s_tb->FL[n_h]) || | |
913 | !buffer_uptodate(p_s_father) || | |
914 | !buffer_uptodate(p_s_tb->FL[n_h]), | |
915 | "vs-8165: F[h] (%b) or FL[h] (%b) is invalid", | |
916 | p_s_father, p_s_tb->FL[n_h]); | |
917 | ||
918 | /* Get position of the pointer to the left neighbor into the left father. */ | |
919 | n_left_neighbor_position = (p_s_father == p_s_tb->FL[n_h]) ? | |
920 | p_s_tb->lkey[n_h] : B_NR_ITEMS(p_s_tb->FL[n_h]); | |
921 | /* Get left neighbor block number. */ | |
922 | n_left_neighbor_blocknr = | |
923 | B_N_CHILD_NUM(p_s_tb->FL[n_h], n_left_neighbor_position); | |
924 | /* Look for the left neighbor in the cache. */ | |
925 | if ((left = sb_find_get_block(p_s_sb, n_left_neighbor_blocknr))) { | |
926 | ||
927 | RFALSE(buffer_uptodate(left) && !B_IS_IN_TREE(left), | |
928 | "vs-8170: left neighbor (%b %z) is not in the tree", | |
929 | left, left); | |
930 | put_bh(left); | |
931 | return 1; | |
932 | } | |
1da177e4 | 933 | |
bd4c625c LT |
934 | return 0; |
935 | } | |
1da177e4 LT |
936 | |
937 | #define LEFT_PARENTS 'l' | |
938 | #define RIGHT_PARENTS 'r' | |
939 | ||
bd4c625c | 940 | static void decrement_key(struct cpu_key *p_s_key) |
1da177e4 | 941 | { |
bd4c625c LT |
942 | // call item specific function for this key |
943 | item_ops[cpu_key_k_type(p_s_key)]->decrement_key(p_s_key); | |
1da177e4 LT |
944 | } |
945 | ||
1da177e4 LT |
946 | /* Calculate far left/right parent of the left/right neighbor of the current node, that |
947 | * is calculate the left/right (FL[h]/FR[h]) neighbor of the parent F[h]. | |
948 | * Calculate left/right common parent of the current node and L[h]/R[h]. | |
949 | * Calculate left/right delimiting key position. | |
950 | * Returns: PATH_INCORRECT - path in the tree is not correct; | |
951 | SCHEDULE_OCCURRED - schedule occurred while the function worked; | |
952 | * CARRY_ON - schedule didn't occur while the function worked; | |
953 | */ | |
bd4c625c LT |
954 | static int get_far_parent(struct tree_balance *p_s_tb, |
955 | int n_h, | |
956 | struct buffer_head **pp_s_father, | |
957 | struct buffer_head **pp_s_com_father, char c_lr_par) | |
1da177e4 | 958 | { |
bd4c625c LT |
959 | struct buffer_head *p_s_parent; |
960 | INITIALIZE_PATH(s_path_to_neighbor_father); | |
961 | struct path *p_s_path = p_s_tb->tb_path; | |
962 | struct cpu_key s_lr_father_key; | |
963 | int n_counter, | |
964 | n_position = INT_MAX, | |
965 | n_first_last_position = 0, | |
966 | n_path_offset = PATH_H_PATH_OFFSET(p_s_path, n_h); | |
967 | ||
968 | /* Starting from F[n_h] go upwards in the tree, and look for the common | |
969 | ancestor of F[n_h], and its neighbor l/r, that should be obtained. */ | |
970 | ||
971 | n_counter = n_path_offset; | |
972 | ||
973 | RFALSE(n_counter < FIRST_PATH_ELEMENT_OFFSET, | |
974 | "PAP-8180: invalid path length"); | |
975 | ||
976 | for (; n_counter > FIRST_PATH_ELEMENT_OFFSET; n_counter--) { | |
977 | /* Check whether parent of the current buffer in the path is really parent in the tree. */ | |
978 | if (!B_IS_IN_TREE | |
979 | (p_s_parent = PATH_OFFSET_PBUFFER(p_s_path, n_counter - 1))) | |
980 | return REPEAT_SEARCH; | |
981 | /* Check whether position in the parent is correct. */ | |
982 | if ((n_position = | |
983 | PATH_OFFSET_POSITION(p_s_path, | |
984 | n_counter - 1)) > | |
985 | B_NR_ITEMS(p_s_parent)) | |
986 | return REPEAT_SEARCH; | |
987 | /* Check whether parent at the path really points to the child. */ | |
988 | if (B_N_CHILD_NUM(p_s_parent, n_position) != | |
989 | PATH_OFFSET_PBUFFER(p_s_path, n_counter)->b_blocknr) | |
990 | return REPEAT_SEARCH; | |
991 | /* Return delimiting key if position in the parent is not equal to first/last one. */ | |
992 | if (c_lr_par == RIGHT_PARENTS) | |
993 | n_first_last_position = B_NR_ITEMS(p_s_parent); | |
994 | if (n_position != n_first_last_position) { | |
995 | *pp_s_com_father = p_s_parent; | |
996 | get_bh(*pp_s_com_father); | |
997 | /*(*pp_s_com_father = p_s_parent)->b_count++; */ | |
998 | break; | |
999 | } | |
1da177e4 | 1000 | } |
bd4c625c LT |
1001 | |
1002 | /* if we are in the root of the tree, then there is no common father */ | |
1003 | if (n_counter == FIRST_PATH_ELEMENT_OFFSET) { | |
1004 | /* Check whether first buffer in the path is the root of the tree. */ | |
1005 | if (PATH_OFFSET_PBUFFER | |
1006 | (p_s_tb->tb_path, | |
1007 | FIRST_PATH_ELEMENT_OFFSET)->b_blocknr == | |
1008 | SB_ROOT_BLOCK(p_s_tb->tb_sb)) { | |
1009 | *pp_s_father = *pp_s_com_father = NULL; | |
1010 | return CARRY_ON; | |
1011 | } | |
1012 | return REPEAT_SEARCH; | |
1da177e4 | 1013 | } |
1da177e4 | 1014 | |
bd4c625c LT |
1015 | RFALSE(B_LEVEL(*pp_s_com_father) <= DISK_LEAF_NODE_LEVEL, |
1016 | "PAP-8185: (%b %z) level too small", | |
1017 | *pp_s_com_father, *pp_s_com_father); | |
1da177e4 | 1018 | |
bd4c625c | 1019 | /* Check whether the common parent is locked. */ |
1da177e4 | 1020 | |
bd4c625c LT |
1021 | if (buffer_locked(*pp_s_com_father)) { |
1022 | __wait_on_buffer(*pp_s_com_father); | |
1023 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { | |
1024 | decrement_bcount(*pp_s_com_father); | |
1025 | return REPEAT_SEARCH; | |
1026 | } | |
1da177e4 | 1027 | } |
1da177e4 | 1028 | |
bd4c625c LT |
1029 | /* So, we got common parent of the current node and its left/right neighbor. |
1030 | Now we are geting the parent of the left/right neighbor. */ | |
1da177e4 | 1031 | |
bd4c625c LT |
1032 | /* Form key to get parent of the left/right neighbor. */ |
1033 | le_key2cpu_key(&s_lr_father_key, | |
1034 | B_N_PDELIM_KEY(*pp_s_com_father, | |
1035 | (c_lr_par == | |
1036 | LEFT_PARENTS) ? (p_s_tb->lkey[n_h - 1] = | |
1037 | n_position - | |
1038 | 1) : (p_s_tb->rkey[n_h - | |
1039 | 1] = | |
1040 | n_position))); | |
1da177e4 | 1041 | |
bd4c625c LT |
1042 | if (c_lr_par == LEFT_PARENTS) |
1043 | decrement_key(&s_lr_father_key); | |
1da177e4 | 1044 | |
bd4c625c LT |
1045 | if (search_by_key |
1046 | (p_s_tb->tb_sb, &s_lr_father_key, &s_path_to_neighbor_father, | |
1047 | n_h + 1) == IO_ERROR) | |
1048 | // path is released | |
1049 | return IO_ERROR; | |
1da177e4 | 1050 | |
bd4c625c LT |
1051 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { |
1052 | decrement_counters_in_path(&s_path_to_neighbor_father); | |
1053 | decrement_bcount(*pp_s_com_father); | |
1054 | return REPEAT_SEARCH; | |
1055 | } | |
1da177e4 | 1056 | |
bd4c625c | 1057 | *pp_s_father = PATH_PLAST_BUFFER(&s_path_to_neighbor_father); |
1da177e4 | 1058 | |
bd4c625c LT |
1059 | RFALSE(B_LEVEL(*pp_s_father) != n_h + 1, |
1060 | "PAP-8190: (%b %z) level too small", *pp_s_father, *pp_s_father); | |
1061 | RFALSE(s_path_to_neighbor_father.path_length < | |
1062 | FIRST_PATH_ELEMENT_OFFSET, "PAP-8192: path length is too small"); | |
1da177e4 | 1063 | |
bd4c625c LT |
1064 | s_path_to_neighbor_father.path_length--; |
1065 | decrement_counters_in_path(&s_path_to_neighbor_father); | |
1066 | return CARRY_ON; | |
1da177e4 LT |
1067 | } |
1068 | ||
1da177e4 LT |
1069 | /* Get parents of neighbors of node in the path(S[n_path_offset]) and common parents of |
1070 | * S[n_path_offset] and L[n_path_offset]/R[n_path_offset]: F[n_path_offset], FL[n_path_offset], | |
1071 | * FR[n_path_offset], CFL[n_path_offset], CFR[n_path_offset]. | |
1072 | * Calculate numbers of left and right delimiting keys position: lkey[n_path_offset], rkey[n_path_offset]. | |
1073 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; | |
1074 | * CARRY_ON - schedule didn't occur while the function worked; | |
1075 | */ | |
bd4c625c | 1076 | static int get_parents(struct tree_balance *p_s_tb, int n_h) |
1da177e4 | 1077 | { |
bd4c625c LT |
1078 | struct path *p_s_path = p_s_tb->tb_path; |
1079 | int n_position, | |
1080 | n_ret_value, | |
1081 | n_path_offset = PATH_H_PATH_OFFSET(p_s_tb->tb_path, n_h); | |
1082 | struct buffer_head *p_s_curf, *p_s_curcf; | |
1083 | ||
1084 | /* Current node is the root of the tree or will be root of the tree */ | |
1085 | if (n_path_offset <= FIRST_PATH_ELEMENT_OFFSET) { | |
1086 | /* The root can not have parents. | |
1087 | Release nodes which previously were obtained as parents of the current node neighbors. */ | |
1088 | decrement_bcount(p_s_tb->FL[n_h]); | |
1089 | decrement_bcount(p_s_tb->CFL[n_h]); | |
1090 | decrement_bcount(p_s_tb->FR[n_h]); | |
1091 | decrement_bcount(p_s_tb->CFR[n_h]); | |
1092 | p_s_tb->FL[n_h] = p_s_tb->CFL[n_h] = p_s_tb->FR[n_h] = | |
1093 | p_s_tb->CFR[n_h] = NULL; | |
1094 | return CARRY_ON; | |
1095 | } | |
1096 | ||
1097 | /* Get parent FL[n_path_offset] of L[n_path_offset]. */ | |
1098 | if ((n_position = PATH_OFFSET_POSITION(p_s_path, n_path_offset - 1))) { | |
1099 | /* Current node is not the first child of its parent. */ | |
1100 | /*(p_s_curf = p_s_curcf = PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1))->b_count += 2; */ | |
1101 | p_s_curf = p_s_curcf = | |
1102 | PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1); | |
1103 | get_bh(p_s_curf); | |
1104 | get_bh(p_s_curf); | |
1105 | p_s_tb->lkey[n_h] = n_position - 1; | |
1106 | } else { | |
1107 | /* Calculate current parent of L[n_path_offset], which is the left neighbor of the current node. | |
1108 | Calculate current common parent of L[n_path_offset] and the current node. Note that | |
1109 | CFL[n_path_offset] not equal FL[n_path_offset] and CFL[n_path_offset] not equal F[n_path_offset]. | |
1110 | Calculate lkey[n_path_offset]. */ | |
1111 | if ((n_ret_value = get_far_parent(p_s_tb, n_h + 1, &p_s_curf, | |
1112 | &p_s_curcf, | |
1113 | LEFT_PARENTS)) != CARRY_ON) | |
1114 | return n_ret_value; | |
1115 | } | |
1116 | ||
1da177e4 | 1117 | decrement_bcount(p_s_tb->FL[n_h]); |
bd4c625c | 1118 | p_s_tb->FL[n_h] = p_s_curf; /* New initialization of FL[n_h]. */ |
1da177e4 | 1119 | decrement_bcount(p_s_tb->CFL[n_h]); |
bd4c625c LT |
1120 | p_s_tb->CFL[n_h] = p_s_curcf; /* New initialization of CFL[n_h]. */ |
1121 | ||
1122 | RFALSE((p_s_curf && !B_IS_IN_TREE(p_s_curf)) || | |
1123 | (p_s_curcf && !B_IS_IN_TREE(p_s_curcf)), | |
1124 | "PAP-8195: FL (%b) or CFL (%b) is invalid", p_s_curf, p_s_curcf); | |
1da177e4 LT |
1125 | |
1126 | /* Get parent FR[n_h] of R[n_h]. */ | |
1127 | ||
1128 | /* Current node is the last child of F[n_h]. FR[n_h] != F[n_h]. */ | |
bd4c625c | 1129 | if (n_position == B_NR_ITEMS(PATH_H_PBUFFER(p_s_path, n_h + 1))) { |
1da177e4 LT |
1130 | /* Calculate current parent of R[n_h], which is the right neighbor of F[n_h]. |
1131 | Calculate current common parent of R[n_h] and current node. Note that CFR[n_h] | |
1132 | not equal FR[n_path_offset] and CFR[n_h] not equal F[n_h]. */ | |
bd4c625c LT |
1133 | if ((n_ret_value = |
1134 | get_far_parent(p_s_tb, n_h + 1, &p_s_curf, &p_s_curcf, | |
1135 | RIGHT_PARENTS)) != CARRY_ON) | |
1136 | return n_ret_value; | |
1137 | } else { | |
1da177e4 | 1138 | /* Current node is not the last child of its parent F[n_h]. */ |
bd4c625c LT |
1139 | /*(p_s_curf = p_s_curcf = PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1))->b_count += 2; */ |
1140 | p_s_curf = p_s_curcf = | |
1141 | PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1); | |
1142 | get_bh(p_s_curf); | |
1143 | get_bh(p_s_curf); | |
1144 | p_s_tb->rkey[n_h] = n_position; | |
1145 | } | |
1da177e4 | 1146 | |
bd4c625c LT |
1147 | decrement_bcount(p_s_tb->FR[n_h]); |
1148 | p_s_tb->FR[n_h] = p_s_curf; /* New initialization of FR[n_path_offset]. */ | |
1149 | ||
1150 | decrement_bcount(p_s_tb->CFR[n_h]); | |
1151 | p_s_tb->CFR[n_h] = p_s_curcf; /* New initialization of CFR[n_path_offset]. */ | |
1152 | ||
1153 | RFALSE((p_s_curf && !B_IS_IN_TREE(p_s_curf)) || | |
1154 | (p_s_curcf && !B_IS_IN_TREE(p_s_curcf)), | |
1155 | "PAP-8205: FR (%b) or CFR (%b) is invalid", p_s_curf, p_s_curcf); | |
1156 | ||
1157 | return CARRY_ON; | |
1158 | } | |
1da177e4 LT |
1159 | |
1160 | /* it is possible to remove node as result of shiftings to | |
1161 | neighbors even when we insert or paste item. */ | |
bd4c625c LT |
1162 | static inline int can_node_be_removed(int mode, int lfree, int sfree, int rfree, |
1163 | struct tree_balance *tb, int h) | |
1da177e4 | 1164 | { |
bd4c625c LT |
1165 | struct buffer_head *Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1166 | int levbytes = tb->insert_size[h]; | |
1167 | struct item_head *ih; | |
1168 | struct reiserfs_key *r_key = NULL; | |
1169 | ||
1170 | ih = B_N_PITEM_HEAD(Sh, 0); | |
1171 | if (tb->CFR[h]) | |
1172 | r_key = B_N_PDELIM_KEY(tb->CFR[h], tb->rkey[h]); | |
1173 | ||
1174 | if (lfree + rfree + sfree < MAX_CHILD_SIZE(Sh) + levbytes | |
1175 | /* shifting may merge items which might save space */ | |
1176 | - | |
1177 | ((!h | |
1178 | && op_is_left_mergeable(&(ih->ih_key), Sh->b_size)) ? IH_SIZE : 0) | |
1179 | - | |
1180 | ((!h && r_key | |
1181 | && op_is_left_mergeable(r_key, Sh->b_size)) ? IH_SIZE : 0) | |
1182 | + ((h) ? KEY_SIZE : 0)) { | |
1183 | /* node can not be removed */ | |
1184 | if (sfree >= levbytes) { /* new item fits into node S[h] without any shifting */ | |
1185 | if (!h) | |
1186 | tb->s0num = | |
1187 | B_NR_ITEMS(Sh) + | |
1188 | ((mode == M_INSERT) ? 1 : 0); | |
1189 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1190 | return NO_BALANCING_NEEDED; | |
1191 | } | |
1da177e4 | 1192 | } |
bd4c625c LT |
1193 | PROC_INFO_INC(tb->tb_sb, can_node_be_removed[h]); |
1194 | return !NO_BALANCING_NEEDED; | |
1da177e4 LT |
1195 | } |
1196 | ||
1da177e4 LT |
1197 | /* Check whether current node S[h] is balanced when increasing its size by |
1198 | * Inserting or Pasting. | |
1199 | * Calculate parameters for balancing for current level h. | |
1200 | * Parameters: | |
1201 | * tb tree_balance structure; | |
1202 | * h current level of the node; | |
1203 | * inum item number in S[h]; | |
1204 | * mode i - insert, p - paste; | |
1205 | * Returns: 1 - schedule occurred; | |
1206 | * 0 - balancing for higher levels needed; | |
1207 | * -1 - no balancing for higher levels needed; | |
1208 | * -2 - no disk space. | |
1209 | */ | |
1210 | /* ip means Inserting or Pasting */ | |
bd4c625c | 1211 | static int ip_check_balance(struct tree_balance *tb, int h) |
1da177e4 | 1212 | { |
bd4c625c LT |
1213 | struct virtual_node *vn = tb->tb_vn; |
1214 | int levbytes, /* Number of bytes that must be inserted into (value | |
1215 | is negative if bytes are deleted) buffer which | |
1216 | contains node being balanced. The mnemonic is | |
1217 | that the attempted change in node space used level | |
1218 | is levbytes bytes. */ | |
1219 | n_ret_value; | |
1220 | ||
1221 | int lfree, sfree, rfree /* free space in L, S and R */ ; | |
1222 | ||
1223 | /* nver is short for number of vertixes, and lnver is the number if | |
1224 | we shift to the left, rnver is the number if we shift to the | |
1225 | right, and lrnver is the number if we shift in both directions. | |
1226 | The goal is to minimize first the number of vertixes, and second, | |
1227 | the number of vertixes whose contents are changed by shifting, | |
1228 | and third the number of uncached vertixes whose contents are | |
1229 | changed by shifting and must be read from disk. */ | |
1230 | int nver, lnver, rnver, lrnver; | |
1231 | ||
1232 | /* used at leaf level only, S0 = S[0] is the node being balanced, | |
1233 | sInum [ I = 0,1,2 ] is the number of items that will | |
1234 | remain in node SI after balancing. S1 and S2 are new | |
1235 | nodes that might be created. */ | |
1236 | ||
1237 | /* we perform 8 calls to get_num_ver(). For each call we calculate five parameters. | |
1238 | where 4th parameter is s1bytes and 5th - s2bytes | |
1239 | */ | |
1240 | short snum012[40] = { 0, }; /* s0num, s1num, s2num for 8 cases | |
1241 | 0,1 - do not shift and do not shift but bottle | |
1242 | 2 - shift only whole item to left | |
1243 | 3 - shift to left and bottle as much as possible | |
1244 | 4,5 - shift to right (whole items and as much as possible | |
1245 | 6,7 - shift to both directions (whole items and as much as possible) | |
1246 | */ | |
1247 | ||
1248 | /* Sh is the node whose balance is currently being checked */ | |
1249 | struct buffer_head *Sh; | |
1250 | ||
1251 | Sh = PATH_H_PBUFFER(tb->tb_path, h); | |
1252 | levbytes = tb->insert_size[h]; | |
1253 | ||
1254 | /* Calculate balance parameters for creating new root. */ | |
1255 | if (!Sh) { | |
1256 | if (!h) | |
1257 | reiserfs_panic(tb->tb_sb, | |
1258 | "vs-8210: ip_check_balance: S[0] can not be 0"); | |
1259 | switch (n_ret_value = get_empty_nodes(tb, h)) { | |
1260 | case CARRY_ON: | |
1261 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1262 | return NO_BALANCING_NEEDED; /* no balancing for higher levels needed */ | |
1263 | ||
1264 | case NO_DISK_SPACE: | |
1265 | case REPEAT_SEARCH: | |
1266 | return n_ret_value; | |
1267 | default: | |
1268 | reiserfs_panic(tb->tb_sb, | |
1269 | "vs-8215: ip_check_balance: incorrect return value of get_empty_nodes"); | |
1270 | } | |
1da177e4 | 1271 | } |
1da177e4 | 1272 | |
bd4c625c LT |
1273 | if ((n_ret_value = get_parents(tb, h)) != CARRY_ON) /* get parents of S[h] neighbors. */ |
1274 | return n_ret_value; | |
1da177e4 | 1275 | |
bd4c625c LT |
1276 | sfree = B_FREE_SPACE(Sh); |
1277 | ||
1278 | /* get free space of neighbors */ | |
1279 | rfree = get_rfree(tb, h); | |
1280 | lfree = get_lfree(tb, h); | |
1281 | ||
1282 | if (can_node_be_removed(vn->vn_mode, lfree, sfree, rfree, tb, h) == | |
1283 | NO_BALANCING_NEEDED) | |
1284 | /* and new item fits into node S[h] without any shifting */ | |
1285 | return NO_BALANCING_NEEDED; | |
1da177e4 | 1286 | |
bd4c625c | 1287 | create_virtual_node(tb, h); |
1da177e4 | 1288 | |
bd4c625c LT |
1289 | /* |
1290 | determine maximal number of items we can shift to the left neighbor (in tb structure) | |
1291 | and the maximal number of bytes that can flow to the left neighbor | |
1292 | from the left most liquid item that cannot be shifted from S[0] entirely (returned value) | |
1da177e4 | 1293 | */ |
bd4c625c | 1294 | check_left(tb, h, lfree); |
1da177e4 | 1295 | |
bd4c625c LT |
1296 | /* |
1297 | determine maximal number of items we can shift to the right neighbor (in tb structure) | |
1298 | and the maximal number of bytes that can flow to the right neighbor | |
1299 | from the right most liquid item that cannot be shifted from S[0] entirely (returned value) | |
1300 | */ | |
1301 | check_right(tb, h, rfree); | |
1302 | ||
1303 | /* all contents of internal node S[h] can be moved into its | |
1304 | neighbors, S[h] will be removed after balancing */ | |
1305 | if (h && (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1)) { | |
1306 | int to_r; | |
1307 | ||
1308 | /* Since we are working on internal nodes, and our internal | |
1309 | nodes have fixed size entries, then we can balance by the | |
1310 | number of items rather than the space they consume. In this | |
1311 | routine we set the left node equal to the right node, | |
1312 | allowing a difference of less than or equal to 1 child | |
1313 | pointer. */ | |
1314 | to_r = | |
1315 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] + | |
1316 | vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - | |
1317 | tb->rnum[h]); | |
1318 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL, | |
1319 | -1, -1); | |
1320 | return CARRY_ON; | |
1321 | } | |
1322 | ||
1323 | /* this checks balance condition, that any two neighboring nodes can not fit in one node */ | |
1324 | RFALSE(h && | |
1325 | (tb->lnum[h] >= vn->vn_nr_item + 1 || | |
1326 | tb->rnum[h] >= vn->vn_nr_item + 1), | |
1327 | "vs-8220: tree is not balanced on internal level"); | |
1328 | RFALSE(!h && ((tb->lnum[h] >= vn->vn_nr_item && (tb->lbytes == -1)) || | |
1329 | (tb->rnum[h] >= vn->vn_nr_item && (tb->rbytes == -1))), | |
1330 | "vs-8225: tree is not balanced on leaf level"); | |
1331 | ||
1332 | /* all contents of S[0] can be moved into its neighbors | |
1333 | S[0] will be removed after balancing. */ | |
1334 | if (!h && is_leaf_removable(tb)) | |
1335 | return CARRY_ON; | |
1336 | ||
1337 | /* why do we perform this check here rather than earlier?? | |
1338 | Answer: we can win 1 node in some cases above. Moreover we | |
1339 | checked it above, when we checked, that S[0] is not removable | |
1340 | in principle */ | |
1341 | if (sfree >= levbytes) { /* new item fits into node S[h] without any shifting */ | |
1342 | if (!h) | |
1343 | tb->s0num = vn->vn_nr_item; | |
1344 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1345 | return NO_BALANCING_NEEDED; | |
1346 | } | |
1347 | ||
1348 | { | |
1349 | int lpar, rpar, nset, lset, rset, lrset; | |
1350 | /* | |
1351 | * regular overflowing of the node | |
1352 | */ | |
1353 | ||
1354 | /* get_num_ver works in 2 modes (FLOW & NO_FLOW) | |
1355 | lpar, rpar - number of items we can shift to left/right neighbor (including splitting item) | |
1356 | nset, lset, rset, lrset - shows, whether flowing items give better packing | |
1357 | */ | |
1da177e4 | 1358 | #define FLOW 1 |
bd4c625c | 1359 | #define NO_FLOW 0 /* do not any splitting */ |
1da177e4 | 1360 | |
bd4c625c | 1361 | /* we choose one the following */ |
1da177e4 LT |
1362 | #define NOTHING_SHIFT_NO_FLOW 0 |
1363 | #define NOTHING_SHIFT_FLOW 5 | |
1364 | #define LEFT_SHIFT_NO_FLOW 10 | |
1365 | #define LEFT_SHIFT_FLOW 15 | |
1366 | #define RIGHT_SHIFT_NO_FLOW 20 | |
1367 | #define RIGHT_SHIFT_FLOW 25 | |
1368 | #define LR_SHIFT_NO_FLOW 30 | |
1369 | #define LR_SHIFT_FLOW 35 | |
1370 | ||
bd4c625c LT |
1371 | lpar = tb->lnum[h]; |
1372 | rpar = tb->rnum[h]; | |
1373 | ||
1374 | /* calculate number of blocks S[h] must be split into when | |
1375 | nothing is shifted to the neighbors, | |
1376 | as well as number of items in each part of the split node (s012 numbers), | |
1377 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any */ | |
1378 | nset = NOTHING_SHIFT_NO_FLOW; | |
1379 | nver = get_num_ver(vn->vn_mode, tb, h, | |
1380 | 0, -1, h ? vn->vn_nr_item : 0, -1, | |
1381 | snum012, NO_FLOW); | |
1382 | ||
1383 | if (!h) { | |
1384 | int nver1; | |
1385 | ||
1386 | /* note, that in this case we try to bottle between S[0] and S1 (S1 - the first new node) */ | |
1387 | nver1 = get_num_ver(vn->vn_mode, tb, h, | |
1388 | 0, -1, 0, -1, | |
1389 | snum012 + NOTHING_SHIFT_FLOW, FLOW); | |
1390 | if (nver > nver1) | |
1391 | nset = NOTHING_SHIFT_FLOW, nver = nver1; | |
1392 | } | |
1da177e4 | 1393 | |
bd4c625c LT |
1394 | /* calculate number of blocks S[h] must be split into when |
1395 | l_shift_num first items and l_shift_bytes of the right most | |
1396 | liquid item to be shifted are shifted to the left neighbor, | |
1397 | as well as number of items in each part of the splitted node (s012 numbers), | |
1398 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any | |
1399 | */ | |
1400 | lset = LEFT_SHIFT_NO_FLOW; | |
1401 | lnver = get_num_ver(vn->vn_mode, tb, h, | |
1402 | lpar - ((h || tb->lbytes == -1) ? 0 : 1), | |
1403 | -1, h ? vn->vn_nr_item : 0, -1, | |
1404 | snum012 + LEFT_SHIFT_NO_FLOW, NO_FLOW); | |
1405 | if (!h) { | |
1406 | int lnver1; | |
1407 | ||
1408 | lnver1 = get_num_ver(vn->vn_mode, tb, h, | |
1409 | lpar - | |
1410 | ((tb->lbytes != -1) ? 1 : 0), | |
1411 | tb->lbytes, 0, -1, | |
1412 | snum012 + LEFT_SHIFT_FLOW, FLOW); | |
1413 | if (lnver > lnver1) | |
1414 | lset = LEFT_SHIFT_FLOW, lnver = lnver1; | |
1415 | } | |
1da177e4 | 1416 | |
bd4c625c LT |
1417 | /* calculate number of blocks S[h] must be split into when |
1418 | r_shift_num first items and r_shift_bytes of the left most | |
1419 | liquid item to be shifted are shifted to the right neighbor, | |
1420 | as well as number of items in each part of the splitted node (s012 numbers), | |
1421 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any | |
1422 | */ | |
1423 | rset = RIGHT_SHIFT_NO_FLOW; | |
1424 | rnver = get_num_ver(vn->vn_mode, tb, h, | |
1425 | 0, -1, | |
1426 | h ? (vn->vn_nr_item - rpar) : (rpar - | |
1427 | ((tb-> | |
1428 | rbytes != | |
1429 | -1) ? 1 : | |
1430 | 0)), -1, | |
1431 | snum012 + RIGHT_SHIFT_NO_FLOW, NO_FLOW); | |
1432 | if (!h) { | |
1433 | int rnver1; | |
1434 | ||
1435 | rnver1 = get_num_ver(vn->vn_mode, tb, h, | |
1436 | 0, -1, | |
1437 | (rpar - | |
1438 | ((tb->rbytes != -1) ? 1 : 0)), | |
1439 | tb->rbytes, | |
1440 | snum012 + RIGHT_SHIFT_FLOW, FLOW); | |
1441 | ||
1442 | if (rnver > rnver1) | |
1443 | rset = RIGHT_SHIFT_FLOW, rnver = rnver1; | |
1444 | } | |
1da177e4 | 1445 | |
bd4c625c LT |
1446 | /* calculate number of blocks S[h] must be split into when |
1447 | items are shifted in both directions, | |
1448 | as well as number of items in each part of the splitted node (s012 numbers), | |
1449 | and number of bytes (s1bytes) of the shared drop which flow to S1 if any | |
1450 | */ | |
1451 | lrset = LR_SHIFT_NO_FLOW; | |
1452 | lrnver = get_num_ver(vn->vn_mode, tb, h, | |
1453 | lpar - ((h || tb->lbytes == -1) ? 0 : 1), | |
1454 | -1, | |
1455 | h ? (vn->vn_nr_item - rpar) : (rpar - | |
1456 | ((tb-> | |
1457 | rbytes != | |
1458 | -1) ? 1 : | |
1459 | 0)), -1, | |
1460 | snum012 + LR_SHIFT_NO_FLOW, NO_FLOW); | |
1461 | if (!h) { | |
1462 | int lrnver1; | |
1463 | ||
1464 | lrnver1 = get_num_ver(vn->vn_mode, tb, h, | |
1465 | lpar - | |
1466 | ((tb->lbytes != -1) ? 1 : 0), | |
1467 | tb->lbytes, | |
1468 | (rpar - | |
1469 | ((tb->rbytes != -1) ? 1 : 0)), | |
1470 | tb->rbytes, | |
1471 | snum012 + LR_SHIFT_FLOW, FLOW); | |
1472 | if (lrnver > lrnver1) | |
1473 | lrset = LR_SHIFT_FLOW, lrnver = lrnver1; | |
1474 | } | |
1da177e4 | 1475 | |
bd4c625c LT |
1476 | /* Our general shifting strategy is: |
1477 | 1) to minimized number of new nodes; | |
1478 | 2) to minimized number of neighbors involved in shifting; | |
1479 | 3) to minimized number of disk reads; */ | |
1480 | ||
1481 | /* we can win TWO or ONE nodes by shifting in both directions */ | |
1482 | if (lrnver < lnver && lrnver < rnver) { | |
1483 | RFALSE(h && | |
1484 | (tb->lnum[h] != 1 || | |
1485 | tb->rnum[h] != 1 || | |
1486 | lrnver != 1 || rnver != 2 || lnver != 2 | |
1487 | || h != 1), "vs-8230: bad h"); | |
1488 | if (lrset == LR_SHIFT_FLOW) | |
1489 | set_parameters(tb, h, tb->lnum[h], tb->rnum[h], | |
1490 | lrnver, snum012 + lrset, | |
1491 | tb->lbytes, tb->rbytes); | |
1492 | else | |
1493 | set_parameters(tb, h, | |
1494 | tb->lnum[h] - | |
1495 | ((tb->lbytes == -1) ? 0 : 1), | |
1496 | tb->rnum[h] - | |
1497 | ((tb->rbytes == -1) ? 0 : 1), | |
1498 | lrnver, snum012 + lrset, -1, -1); | |
1499 | ||
1500 | return CARRY_ON; | |
1501 | } | |
1da177e4 | 1502 | |
bd4c625c LT |
1503 | /* if shifting doesn't lead to better packing then don't shift */ |
1504 | if (nver == lrnver) { | |
1505 | set_parameters(tb, h, 0, 0, nver, snum012 + nset, -1, | |
1506 | -1); | |
1507 | return CARRY_ON; | |
1508 | } | |
1da177e4 | 1509 | |
bd4c625c LT |
1510 | /* now we know that for better packing shifting in only one |
1511 | direction either to the left or to the right is required */ | |
1da177e4 | 1512 | |
bd4c625c LT |
1513 | /* if shifting to the left is better than shifting to the right */ |
1514 | if (lnver < rnver) { | |
1515 | SET_PAR_SHIFT_LEFT; | |
1516 | return CARRY_ON; | |
1517 | } | |
1da177e4 | 1518 | |
bd4c625c LT |
1519 | /* if shifting to the right is better than shifting to the left */ |
1520 | if (lnver > rnver) { | |
1521 | SET_PAR_SHIFT_RIGHT; | |
1522 | return CARRY_ON; | |
1523 | } | |
1da177e4 | 1524 | |
bd4c625c LT |
1525 | /* now shifting in either direction gives the same number |
1526 | of nodes and we can make use of the cached neighbors */ | |
1527 | if (is_left_neighbor_in_cache(tb, h)) { | |
1528 | SET_PAR_SHIFT_LEFT; | |
1529 | return CARRY_ON; | |
1530 | } | |
1da177e4 | 1531 | |
bd4c625c LT |
1532 | /* shift to the right independently on whether the right neighbor in cache or not */ |
1533 | SET_PAR_SHIFT_RIGHT; | |
1534 | return CARRY_ON; | |
1da177e4 | 1535 | } |
1da177e4 LT |
1536 | } |
1537 | ||
1da177e4 LT |
1538 | /* Check whether current node S[h] is balanced when Decreasing its size by |
1539 | * Deleting or Cutting for INTERNAL node of S+tree. | |
1540 | * Calculate parameters for balancing for current level h. | |
1541 | * Parameters: | |
1542 | * tb tree_balance structure; | |
1543 | * h current level of the node; | |
1544 | * inum item number in S[h]; | |
1545 | * mode i - insert, p - paste; | |
1546 | * Returns: 1 - schedule occurred; | |
1547 | * 0 - balancing for higher levels needed; | |
1548 | * -1 - no balancing for higher levels needed; | |
1549 | * -2 - no disk space. | |
1550 | * | |
1551 | * Note: Items of internal nodes have fixed size, so the balance condition for | |
1552 | * the internal part of S+tree is as for the B-trees. | |
1553 | */ | |
bd4c625c | 1554 | static int dc_check_balance_internal(struct tree_balance *tb, int h) |
1da177e4 | 1555 | { |
bd4c625c | 1556 | struct virtual_node *vn = tb->tb_vn; |
1da177e4 | 1557 | |
bd4c625c LT |
1558 | /* Sh is the node whose balance is currently being checked, |
1559 | and Fh is its father. */ | |
1560 | struct buffer_head *Sh, *Fh; | |
1561 | int maxsize, n_ret_value; | |
1562 | int lfree, rfree /* free space in L and R */ ; | |
1da177e4 | 1563 | |
bd4c625c LT |
1564 | Sh = PATH_H_PBUFFER(tb->tb_path, h); |
1565 | Fh = PATH_H_PPARENT(tb->tb_path, h); | |
1da177e4 | 1566 | |
bd4c625c | 1567 | maxsize = MAX_CHILD_SIZE(Sh); |
1da177e4 LT |
1568 | |
1569 | /* using tb->insert_size[h], which is negative in this case, create_virtual_node calculates: */ | |
1570 | /* new_nr_item = number of items node would have if operation is */ | |
1571 | /* performed without balancing (new_nr_item); */ | |
bd4c625c | 1572 | create_virtual_node(tb, h); |
1da177e4 | 1573 | |
bd4c625c LT |
1574 | if (!Fh) { /* S[h] is the root. */ |
1575 | if (vn->vn_nr_item > 0) { | |
1576 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1577 | return NO_BALANCING_NEEDED; /* no balancing for higher levels needed */ | |
1578 | } | |
1579 | /* new_nr_item == 0. | |
1580 | * Current root will be deleted resulting in | |
1581 | * decrementing the tree height. */ | |
1582 | set_parameters(tb, h, 0, 0, 0, NULL, -1, -1); | |
1583 | return CARRY_ON; | |
1584 | } | |
1585 | ||
1586 | if ((n_ret_value = get_parents(tb, h)) != CARRY_ON) | |
1587 | return n_ret_value; | |
1588 | ||
1589 | /* get free space of neighbors */ | |
1590 | rfree = get_rfree(tb, h); | |
1591 | lfree = get_lfree(tb, h); | |
1592 | ||
1593 | /* determine maximal number of items we can fit into neighbors */ | |
1594 | check_left(tb, h, lfree); | |
1595 | check_right(tb, h, rfree); | |
1596 | ||
1597 | if (vn->vn_nr_item >= MIN_NR_KEY(Sh)) { /* Balance condition for the internal node is valid. | |
1598 | * In this case we balance only if it leads to better packing. */ | |
1599 | if (vn->vn_nr_item == MIN_NR_KEY(Sh)) { /* Here we join S[h] with one of its neighbors, | |
1600 | * which is impossible with greater values of new_nr_item. */ | |
1601 | if (tb->lnum[h] >= vn->vn_nr_item + 1) { | |
1602 | /* All contents of S[h] can be moved to L[h]. */ | |
1603 | int n; | |
1604 | int order_L; | |
1605 | ||
1606 | order_L = | |
1607 | ((n = | |
1608 | PATH_H_B_ITEM_ORDER(tb->tb_path, | |
1609 | h)) == | |
1610 | 0) ? B_NR_ITEMS(tb->FL[h]) : n - 1; | |
1611 | n = dc_size(B_N_CHILD(tb->FL[h], order_L)) / | |
1612 | (DC_SIZE + KEY_SIZE); | |
1613 | set_parameters(tb, h, -n - 1, 0, 0, NULL, -1, | |
1614 | -1); | |
1615 | return CARRY_ON; | |
1616 | } | |
1617 | ||
1618 | if (tb->rnum[h] >= vn->vn_nr_item + 1) { | |
1619 | /* All contents of S[h] can be moved to R[h]. */ | |
1620 | int n; | |
1621 | int order_R; | |
1622 | ||
1623 | order_R = | |
1624 | ((n = | |
1625 | PATH_H_B_ITEM_ORDER(tb->tb_path, | |
1626 | h)) == | |
1627 | B_NR_ITEMS(Fh)) ? 0 : n + 1; | |
1628 | n = dc_size(B_N_CHILD(tb->FR[h], order_R)) / | |
1629 | (DC_SIZE + KEY_SIZE); | |
1630 | set_parameters(tb, h, 0, -n - 1, 0, NULL, -1, | |
1631 | -1); | |
1632 | return CARRY_ON; | |
1633 | } | |
1634 | } | |
1635 | ||
1636 | if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) { | |
1637 | /* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */ | |
1638 | int to_r; | |
1639 | ||
1640 | to_r = | |
1641 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - | |
1642 | tb->rnum[h] + vn->vn_nr_item + 1) / 2 - | |
1643 | (MAX_NR_KEY(Sh) + 1 - tb->rnum[h]); | |
1644 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, | |
1645 | 0, NULL, -1, -1); | |
1646 | return CARRY_ON; | |
1647 | } | |
1648 | ||
1649 | /* Balancing does not lead to better packing. */ | |
1650 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1651 | return NO_BALANCING_NEEDED; | |
1da177e4 | 1652 | } |
bd4c625c LT |
1653 | |
1654 | /* Current node contain insufficient number of items. Balancing is required. */ | |
1655 | /* Check whether we can merge S[h] with left neighbor. */ | |
1656 | if (tb->lnum[h] >= vn->vn_nr_item + 1) | |
1657 | if (is_left_neighbor_in_cache(tb, h) | |
1658 | || tb->rnum[h] < vn->vn_nr_item + 1 || !tb->FR[h]) { | |
1659 | int n; | |
1660 | int order_L; | |
1661 | ||
1662 | order_L = | |
1663 | ((n = | |
1664 | PATH_H_B_ITEM_ORDER(tb->tb_path, | |
1665 | h)) == | |
1666 | 0) ? B_NR_ITEMS(tb->FL[h]) : n - 1; | |
1667 | n = dc_size(B_N_CHILD(tb->FL[h], order_L)) / (DC_SIZE + | |
1668 | KEY_SIZE); | |
1669 | set_parameters(tb, h, -n - 1, 0, 0, NULL, -1, -1); | |
1670 | return CARRY_ON; | |
1671 | } | |
1672 | ||
1673 | /* Check whether we can merge S[h] with right neighbor. */ | |
1674 | if (tb->rnum[h] >= vn->vn_nr_item + 1) { | |
1675 | int n; | |
1676 | int order_R; | |
1677 | ||
1678 | order_R = | |
1679 | ((n = | |
1680 | PATH_H_B_ITEM_ORDER(tb->tb_path, | |
1681 | h)) == B_NR_ITEMS(Fh)) ? 0 : (n + 1); | |
1682 | n = dc_size(B_N_CHILD(tb->FR[h], order_R)) / (DC_SIZE + | |
1683 | KEY_SIZE); | |
1684 | set_parameters(tb, h, 0, -n - 1, 0, NULL, -1, -1); | |
1685 | return CARRY_ON; | |
1da177e4 LT |
1686 | } |
1687 | ||
bd4c625c LT |
1688 | /* All contents of S[h] can be moved to the neighbors (L[h] & R[h]). */ |
1689 | if (tb->rnum[h] + tb->lnum[h] >= vn->vn_nr_item + 1) { | |
1690 | int to_r; | |
1691 | ||
1692 | to_r = | |
1693 | ((MAX_NR_KEY(Sh) << 1) + 2 - tb->lnum[h] - tb->rnum[h] + | |
1694 | vn->vn_nr_item + 1) / 2 - (MAX_NR_KEY(Sh) + 1 - | |
1695 | tb->rnum[h]); | |
1696 | set_parameters(tb, h, vn->vn_nr_item + 1 - to_r, to_r, 0, NULL, | |
1697 | -1, -1); | |
1698 | return CARRY_ON; | |
1699 | } | |
1da177e4 | 1700 | |
bd4c625c LT |
1701 | /* For internal nodes try to borrow item from a neighbor */ |
1702 | RFALSE(!tb->FL[h] && !tb->FR[h], "vs-8235: trying to borrow for root"); | |
1703 | ||
1704 | /* Borrow one or two items from caching neighbor */ | |
1705 | if (is_left_neighbor_in_cache(tb, h) || !tb->FR[h]) { | |
1706 | int from_l; | |
1707 | ||
1708 | from_l = | |
1709 | (MAX_NR_KEY(Sh) + 1 - tb->lnum[h] + vn->vn_nr_item + | |
1710 | 1) / 2 - (vn->vn_nr_item + 1); | |
1711 | set_parameters(tb, h, -from_l, 0, 1, NULL, -1, -1); | |
1712 | return CARRY_ON; | |
1da177e4 LT |
1713 | } |
1714 | ||
bd4c625c LT |
1715 | set_parameters(tb, h, 0, |
1716 | -((MAX_NR_KEY(Sh) + 1 - tb->rnum[h] + vn->vn_nr_item + | |
1717 | 1) / 2 - (vn->vn_nr_item + 1)), 1, NULL, -1, -1); | |
1da177e4 | 1718 | return CARRY_ON; |
1da177e4 LT |
1719 | } |
1720 | ||
1da177e4 LT |
1721 | /* Check whether current node S[h] is balanced when Decreasing its size by |
1722 | * Deleting or Truncating for LEAF node of S+tree. | |
1723 | * Calculate parameters for balancing for current level h. | |
1724 | * Parameters: | |
1725 | * tb tree_balance structure; | |
1726 | * h current level of the node; | |
1727 | * inum item number in S[h]; | |
1728 | * mode i - insert, p - paste; | |
1729 | * Returns: 1 - schedule occurred; | |
1730 | * 0 - balancing for higher levels needed; | |
1731 | * -1 - no balancing for higher levels needed; | |
1732 | * -2 - no disk space. | |
1733 | */ | |
bd4c625c | 1734 | static int dc_check_balance_leaf(struct tree_balance *tb, int h) |
1da177e4 | 1735 | { |
bd4c625c LT |
1736 | struct virtual_node *vn = tb->tb_vn; |
1737 | ||
1738 | /* Number of bytes that must be deleted from | |
1739 | (value is negative if bytes are deleted) buffer which | |
1740 | contains node being balanced. The mnemonic is that the | |
1741 | attempted change in node space used level is levbytes bytes. */ | |
1742 | int levbytes; | |
1743 | /* the maximal item size */ | |
1744 | int maxsize, n_ret_value; | |
1745 | /* S0 is the node whose balance is currently being checked, | |
1746 | and F0 is its father. */ | |
1747 | struct buffer_head *S0, *F0; | |
1748 | int lfree, rfree /* free space in L and R */ ; | |
1749 | ||
1750 | S0 = PATH_H_PBUFFER(tb->tb_path, 0); | |
1751 | F0 = PATH_H_PPARENT(tb->tb_path, 0); | |
1da177e4 | 1752 | |
bd4c625c | 1753 | levbytes = tb->insert_size[h]; |
1da177e4 | 1754 | |
bd4c625c LT |
1755 | maxsize = MAX_CHILD_SIZE(S0); /* maximal possible size of an item */ |
1756 | ||
1757 | if (!F0) { /* S[0] is the root now. */ | |
1758 | ||
1759 | RFALSE(-levbytes >= maxsize - B_FREE_SPACE(S0), | |
1760 | "vs-8240: attempt to create empty buffer tree"); | |
1761 | ||
1762 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1763 | return NO_BALANCING_NEEDED; | |
1764 | } | |
1765 | ||
1766 | if ((n_ret_value = get_parents(tb, h)) != CARRY_ON) | |
1767 | return n_ret_value; | |
1768 | ||
1769 | /* get free space of neighbors */ | |
1770 | rfree = get_rfree(tb, h); | |
1771 | lfree = get_lfree(tb, h); | |
1772 | ||
1773 | create_virtual_node(tb, h); | |
1774 | ||
1775 | /* if 3 leaves can be merge to one, set parameters and return */ | |
1776 | if (are_leaves_removable(tb, lfree, rfree)) | |
1777 | return CARRY_ON; | |
1778 | ||
1779 | /* determine maximal number of items we can shift to the left/right neighbor | |
1780 | and the maximal number of bytes that can flow to the left/right neighbor | |
1781 | from the left/right most liquid item that cannot be shifted from S[0] entirely | |
1782 | */ | |
1783 | check_left(tb, h, lfree); | |
1784 | check_right(tb, h, rfree); | |
1785 | ||
1786 | /* check whether we can merge S with left neighbor. */ | |
1787 | if (tb->lnum[0] >= vn->vn_nr_item && tb->lbytes == -1) | |
1788 | 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 */ | |
1789 | !tb->FR[h]) { | |
1790 | ||
1791 | RFALSE(!tb->FL[h], | |
1792 | "vs-8245: dc_check_balance_leaf: FL[h] must exist"); | |
1793 | ||
1794 | /* set parameter to merge S[0] with its left neighbor */ | |
1795 | set_parameters(tb, h, -1, 0, 0, NULL, -1, -1); | |
1796 | return CARRY_ON; | |
1797 | } | |
1798 | ||
1799 | /* check whether we can merge S[0] with right neighbor. */ | |
1800 | if (tb->rnum[0] >= vn->vn_nr_item && tb->rbytes == -1) { | |
1801 | set_parameters(tb, h, 0, -1, 0, NULL, -1, -1); | |
1802 | return CARRY_ON; | |
1803 | } | |
1804 | ||
1805 | /* All contents of S[0] can be moved to the neighbors (L[0] & R[0]). Set parameters and return */ | |
1806 | if (is_leaf_removable(tb)) | |
1807 | return CARRY_ON; | |
1808 | ||
1809 | /* Balancing is not required. */ | |
1810 | tb->s0num = vn->vn_nr_item; | |
1811 | set_parameters(tb, h, 0, 0, 1, NULL, -1, -1); | |
1812 | return NO_BALANCING_NEEDED; | |
1813 | } | |
1da177e4 LT |
1814 | |
1815 | /* Check whether current node S[h] is balanced when Decreasing its size by | |
1816 | * Deleting or Cutting. | |
1817 | * Calculate parameters for balancing for current level h. | |
1818 | * Parameters: | |
1819 | * tb tree_balance structure; | |
1820 | * h current level of the node; | |
1821 | * inum item number in S[h]; | |
1822 | * mode d - delete, c - cut. | |
1823 | * Returns: 1 - schedule occurred; | |
1824 | * 0 - balancing for higher levels needed; | |
1825 | * -1 - no balancing for higher levels needed; | |
1826 | * -2 - no disk space. | |
1827 | */ | |
bd4c625c | 1828 | static int dc_check_balance(struct tree_balance *tb, int h) |
1da177e4 | 1829 | { |
bd4c625c LT |
1830 | RFALSE(!(PATH_H_PBUFFER(tb->tb_path, h)), |
1831 | "vs-8250: S is not initialized"); | |
1da177e4 | 1832 | |
bd4c625c LT |
1833 | if (h) |
1834 | return dc_check_balance_internal(tb, h); | |
1835 | else | |
1836 | return dc_check_balance_leaf(tb, h); | |
1da177e4 LT |
1837 | } |
1838 | ||
1da177e4 LT |
1839 | /* Check whether current node S[h] is balanced. |
1840 | * Calculate parameters for balancing for current level h. | |
1841 | * Parameters: | |
1842 | * | |
1843 | * tb tree_balance structure: | |
1844 | * | |
1845 | * tb is a large structure that must be read about in the header file | |
1846 | * at the same time as this procedure if the reader is to successfully | |
1847 | * understand this procedure | |
1848 | * | |
1849 | * h current level of the node; | |
1850 | * inum item number in S[h]; | |
1851 | * mode i - insert, p - paste, d - delete, c - cut. | |
1852 | * Returns: 1 - schedule occurred; | |
1853 | * 0 - balancing for higher levels needed; | |
1854 | * -1 - no balancing for higher levels needed; | |
1855 | * -2 - no disk space. | |
1856 | */ | |
bd4c625c LT |
1857 | static int check_balance(int mode, |
1858 | struct tree_balance *tb, | |
1859 | int h, | |
1860 | int inum, | |
1861 | int pos_in_item, | |
1862 | struct item_head *ins_ih, const void *data) | |
1da177e4 | 1863 | { |
bd4c625c | 1864 | struct virtual_node *vn; |
1da177e4 | 1865 | |
bd4c625c LT |
1866 | vn = tb->tb_vn = (struct virtual_node *)(tb->vn_buf); |
1867 | vn->vn_free_ptr = (char *)(tb->tb_vn + 1); | |
1868 | vn->vn_mode = mode; | |
1869 | vn->vn_affected_item_num = inum; | |
1870 | vn->vn_pos_in_item = pos_in_item; | |
1871 | vn->vn_ins_ih = ins_ih; | |
1872 | vn->vn_data = data; | |
1da177e4 | 1873 | |
bd4c625c LT |
1874 | RFALSE(mode == M_INSERT && !vn->vn_ins_ih, |
1875 | "vs-8255: ins_ih can not be 0 in insert mode"); | |
1da177e4 | 1876 | |
bd4c625c LT |
1877 | if (tb->insert_size[h] > 0) |
1878 | /* Calculate balance parameters when size of node is increasing. */ | |
1879 | return ip_check_balance(tb, h); | |
1da177e4 | 1880 | |
bd4c625c LT |
1881 | /* Calculate balance parameters when size of node is decreasing. */ |
1882 | return dc_check_balance(tb, h); | |
1da177e4 LT |
1883 | } |
1884 | ||
bd4c625c LT |
1885 | /* Check whether parent at the path is the really parent of the current node.*/ |
1886 | static int get_direct_parent(struct tree_balance *p_s_tb, int n_h) | |
1887 | { | |
1888 | struct buffer_head *p_s_bh; | |
1889 | struct path *p_s_path = p_s_tb->tb_path; | |
1890 | int n_position, | |
1891 | n_path_offset = PATH_H_PATH_OFFSET(p_s_tb->tb_path, n_h); | |
1892 | ||
1893 | /* We are in the root or in the new root. */ | |
1894 | if (n_path_offset <= FIRST_PATH_ELEMENT_OFFSET) { | |
1895 | ||
1896 | RFALSE(n_path_offset < FIRST_PATH_ELEMENT_OFFSET - 1, | |
1897 | "PAP-8260: invalid offset in the path"); | |
1898 | ||
1899 | if (PATH_OFFSET_PBUFFER(p_s_path, FIRST_PATH_ELEMENT_OFFSET)-> | |
1900 | b_blocknr == SB_ROOT_BLOCK(p_s_tb->tb_sb)) { | |
1901 | /* Root is not changed. */ | |
1902 | PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1) = NULL; | |
1903 | PATH_OFFSET_POSITION(p_s_path, n_path_offset - 1) = 0; | |
1904 | return CARRY_ON; | |
1905 | } | |
1906 | return REPEAT_SEARCH; /* Root is changed and we must recalculate the path. */ | |
1907 | } | |
1908 | ||
1909 | if (!B_IS_IN_TREE | |
1910 | (p_s_bh = PATH_OFFSET_PBUFFER(p_s_path, n_path_offset - 1))) | |
1911 | return REPEAT_SEARCH; /* Parent in the path is not in the tree. */ | |
1da177e4 | 1912 | |
bd4c625c LT |
1913 | if ((n_position = |
1914 | PATH_OFFSET_POSITION(p_s_path, | |
1915 | n_path_offset - 1)) > B_NR_ITEMS(p_s_bh)) | |
1916 | return REPEAT_SEARCH; | |
1da177e4 | 1917 | |
bd4c625c LT |
1918 | if (B_N_CHILD_NUM(p_s_bh, n_position) != |
1919 | PATH_OFFSET_PBUFFER(p_s_path, n_path_offset)->b_blocknr) | |
1920 | /* Parent in the path is not parent of the current node in the tree. */ | |
1921 | return REPEAT_SEARCH; | |
1922 | ||
1923 | if (buffer_locked(p_s_bh)) { | |
1924 | __wait_on_buffer(p_s_bh); | |
1925 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) | |
1926 | return REPEAT_SEARCH; | |
1da177e4 | 1927 | } |
1da177e4 | 1928 | |
bd4c625c LT |
1929 | return CARRY_ON; /* Parent in the path is unlocked and really parent of the current node. */ |
1930 | } | |
1da177e4 LT |
1931 | |
1932 | /* Using lnum[n_h] and rnum[n_h] we should determine what neighbors | |
1933 | * of S[n_h] we | |
1934 | * need in order to balance S[n_h], and get them if necessary. | |
1935 | * Returns: SCHEDULE_OCCURRED - schedule occurred while the function worked; | |
1936 | * CARRY_ON - schedule didn't occur while the function worked; | |
1937 | */ | |
bd4c625c LT |
1938 | static int get_neighbors(struct tree_balance *p_s_tb, int n_h) |
1939 | { | |
1940 | int n_child_position, | |
1941 | n_path_offset = PATH_H_PATH_OFFSET(p_s_tb->tb_path, n_h + 1); | |
1942 | unsigned long n_son_number; | |
1943 | struct super_block *p_s_sb = p_s_tb->tb_sb; | |
1944 | struct buffer_head *p_s_bh; | |
1945 | ||
1946 | PROC_INFO_INC(p_s_sb, get_neighbors[n_h]); | |
1947 | ||
1948 | if (p_s_tb->lnum[n_h]) { | |
1949 | /* We need left neighbor to balance S[n_h]. */ | |
1950 | PROC_INFO_INC(p_s_sb, need_l_neighbor[n_h]); | |
1951 | p_s_bh = PATH_OFFSET_PBUFFER(p_s_tb->tb_path, n_path_offset); | |
1952 | ||
1953 | RFALSE(p_s_bh == p_s_tb->FL[n_h] && | |
1954 | !PATH_OFFSET_POSITION(p_s_tb->tb_path, n_path_offset), | |
1955 | "PAP-8270: invalid position in the parent"); | |
1956 | ||
1957 | n_child_position = | |
1958 | (p_s_bh == | |
1959 | p_s_tb->FL[n_h]) ? p_s_tb->lkey[n_h] : B_NR_ITEMS(p_s_tb-> | |
1960 | FL[n_h]); | |
1961 | n_son_number = B_N_CHILD_NUM(p_s_tb->FL[n_h], n_child_position); | |
1962 | p_s_bh = sb_bread(p_s_sb, n_son_number); | |
1963 | if (!p_s_bh) | |
1964 | return IO_ERROR; | |
1965 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { | |
1966 | decrement_bcount(p_s_bh); | |
1967 | PROC_INFO_INC(p_s_sb, get_neighbors_restart[n_h]); | |
1968 | return REPEAT_SEARCH; | |
1969 | } | |
1970 | ||
1971 | RFALSE(!B_IS_IN_TREE(p_s_tb->FL[n_h]) || | |
1972 | n_child_position > B_NR_ITEMS(p_s_tb->FL[n_h]) || | |
1973 | B_N_CHILD_NUM(p_s_tb->FL[n_h], n_child_position) != | |
1974 | p_s_bh->b_blocknr, "PAP-8275: invalid parent"); | |
1975 | RFALSE(!B_IS_IN_TREE(p_s_bh), "PAP-8280: invalid child"); | |
1976 | RFALSE(!n_h && | |
1977 | B_FREE_SPACE(p_s_bh) != | |
1978 | MAX_CHILD_SIZE(p_s_bh) - | |
1979 | dc_size(B_N_CHILD(p_s_tb->FL[0], n_child_position)), | |
1980 | "PAP-8290: invalid child size of left neighbor"); | |
1981 | ||
1982 | decrement_bcount(p_s_tb->L[n_h]); | |
1983 | p_s_tb->L[n_h] = p_s_bh; | |
1da177e4 | 1984 | } |
bd4c625c LT |
1985 | |
1986 | if (p_s_tb->rnum[n_h]) { /* We need right neighbor to balance S[n_path_offset]. */ | |
1987 | PROC_INFO_INC(p_s_sb, need_r_neighbor[n_h]); | |
1988 | p_s_bh = PATH_OFFSET_PBUFFER(p_s_tb->tb_path, n_path_offset); | |
1989 | ||
1990 | RFALSE(p_s_bh == p_s_tb->FR[n_h] && | |
1991 | PATH_OFFSET_POSITION(p_s_tb->tb_path, | |
1992 | n_path_offset) >= | |
1993 | B_NR_ITEMS(p_s_bh), | |
1994 | "PAP-8295: invalid position in the parent"); | |
1995 | ||
1996 | n_child_position = | |
1997 | (p_s_bh == p_s_tb->FR[n_h]) ? p_s_tb->rkey[n_h] + 1 : 0; | |
1998 | n_son_number = B_N_CHILD_NUM(p_s_tb->FR[n_h], n_child_position); | |
1999 | p_s_bh = sb_bread(p_s_sb, n_son_number); | |
2000 | if (!p_s_bh) | |
2001 | return IO_ERROR; | |
2002 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { | |
2003 | decrement_bcount(p_s_bh); | |
2004 | PROC_INFO_INC(p_s_sb, get_neighbors_restart[n_h]); | |
2005 | return REPEAT_SEARCH; | |
2006 | } | |
2007 | decrement_bcount(p_s_tb->R[n_h]); | |
2008 | p_s_tb->R[n_h] = p_s_bh; | |
2009 | ||
2010 | RFALSE(!n_h | |
2011 | && B_FREE_SPACE(p_s_bh) != | |
2012 | MAX_CHILD_SIZE(p_s_bh) - | |
2013 | dc_size(B_N_CHILD(p_s_tb->FR[0], n_child_position)), | |
2014 | "PAP-8300: invalid child size of right neighbor (%d != %d - %d)", | |
2015 | B_FREE_SPACE(p_s_bh), MAX_CHILD_SIZE(p_s_bh), | |
2016 | dc_size(B_N_CHILD(p_s_tb->FR[0], n_child_position))); | |
2017 | ||
1da177e4 | 2018 | } |
bd4c625c | 2019 | return CARRY_ON; |
1da177e4 LT |
2020 | } |
2021 | ||
bd4c625c | 2022 | static int get_virtual_node_size(struct super_block *sb, struct buffer_head *bh) |
1da177e4 | 2023 | { |
bd4c625c LT |
2024 | int max_num_of_items; |
2025 | int max_num_of_entries; | |
2026 | unsigned long blocksize = sb->s_blocksize; | |
1da177e4 LT |
2027 | |
2028 | #define MIN_NAME_LEN 1 | |
2029 | ||
bd4c625c LT |
2030 | max_num_of_items = (blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN); |
2031 | max_num_of_entries = (blocksize - BLKH_SIZE - IH_SIZE) / | |
2032 | (DEH_SIZE + MIN_NAME_LEN); | |
1da177e4 | 2033 | |
bd4c625c LT |
2034 | return sizeof(struct virtual_node) + |
2035 | max(max_num_of_items * sizeof(struct virtual_item), | |
2036 | sizeof(struct virtual_item) + sizeof(struct direntry_uarea) + | |
2037 | (max_num_of_entries - 1) * sizeof(__u16)); | |
1da177e4 LT |
2038 | } |
2039 | ||
1da177e4 LT |
2040 | /* maybe we should fail balancing we are going to perform when kmalloc |
2041 | fails several times. But now it will loop until kmalloc gets | |
2042 | required memory */ | |
bd4c625c | 2043 | static int get_mem_for_virtual_node(struct tree_balance *tb) |
1da177e4 | 2044 | { |
bd4c625c LT |
2045 | int check_fs = 0; |
2046 | int size; | |
2047 | char *buf; | |
2048 | ||
2049 | size = get_virtual_node_size(tb->tb_sb, PATH_PLAST_BUFFER(tb->tb_path)); | |
2050 | ||
2051 | if (size > tb->vn_buf_size) { | |
2052 | /* we have to allocate more memory for virtual node */ | |
2053 | if (tb->vn_buf) { | |
2054 | /* free memory allocated before */ | |
d739b42b | 2055 | kfree(tb->vn_buf); |
bd4c625c LT |
2056 | /* this is not needed if kfree is atomic */ |
2057 | check_fs = 1; | |
2058 | } | |
1da177e4 | 2059 | |
bd4c625c LT |
2060 | /* virtual node requires now more memory */ |
2061 | tb->vn_buf_size = size; | |
2062 | ||
2063 | /* get memory for virtual item */ | |
d739b42b | 2064 | buf = kmalloc(size, GFP_ATOMIC | __GFP_NOWARN); |
bd4c625c LT |
2065 | if (!buf) { |
2066 | /* getting memory with GFP_KERNEL priority may involve | |
2067 | balancing now (due to indirect_to_direct conversion on | |
2068 | dcache shrinking). So, release path and collected | |
2069 | resources here */ | |
2070 | free_buffers_in_tb(tb); | |
d739b42b | 2071 | buf = kmalloc(size, GFP_NOFS); |
bd4c625c | 2072 | if (!buf) { |
bd4c625c LT |
2073 | tb->vn_buf_size = 0; |
2074 | } | |
2075 | tb->vn_buf = buf; | |
2076 | schedule(); | |
2077 | return REPEAT_SEARCH; | |
2078 | } | |
1da177e4 | 2079 | |
bd4c625c LT |
2080 | tb->vn_buf = buf; |
2081 | } | |
1da177e4 | 2082 | |
bd4c625c LT |
2083 | if (check_fs && FILESYSTEM_CHANGED_TB(tb)) |
2084 | return REPEAT_SEARCH; | |
1da177e4 | 2085 | |
bd4c625c | 2086 | return CARRY_ON; |
1da177e4 LT |
2087 | } |
2088 | ||
1da177e4 | 2089 | #ifdef CONFIG_REISERFS_CHECK |
bd4c625c LT |
2090 | static void tb_buffer_sanity_check(struct super_block *p_s_sb, |
2091 | struct buffer_head *p_s_bh, | |
2092 | const char *descr, int level) | |
1da177e4 | 2093 | { |
bd4c625c LT |
2094 | if (p_s_bh) { |
2095 | if (atomic_read(&(p_s_bh->b_count)) <= 0) { | |
1da177e4 | 2096 | |
bd4c625c LT |
2097 | reiserfs_panic(p_s_sb, |
2098 | "jmacd-1: tb_buffer_sanity_check(): negative or zero reference counter for buffer %s[%d] (%b)\n", | |
2099 | descr, level, p_s_bh); | |
1da177e4 | 2100 | } |
1da177e4 | 2101 | |
bd4c625c LT |
2102 | if (!buffer_uptodate(p_s_bh)) { |
2103 | reiserfs_panic(p_s_sb, | |
2104 | "jmacd-2: tb_buffer_sanity_check(): buffer is not up to date %s[%d] (%b)\n", | |
2105 | descr, level, p_s_bh); | |
2106 | } | |
1da177e4 | 2107 | |
bd4c625c LT |
2108 | if (!B_IS_IN_TREE(p_s_bh)) { |
2109 | reiserfs_panic(p_s_sb, | |
2110 | "jmacd-3: tb_buffer_sanity_check(): buffer is not in tree %s[%d] (%b)\n", | |
2111 | descr, level, p_s_bh); | |
2112 | } | |
1da177e4 | 2113 | |
bd4c625c LT |
2114 | if (p_s_bh->b_bdev != p_s_sb->s_bdev) { |
2115 | reiserfs_panic(p_s_sb, | |
2116 | "jmacd-4: tb_buffer_sanity_check(): buffer has wrong device %s[%d] (%b)\n", | |
2117 | descr, level, p_s_bh); | |
1da177e4 LT |
2118 | } |
2119 | ||
bd4c625c LT |
2120 | if (p_s_bh->b_size != p_s_sb->s_blocksize) { |
2121 | reiserfs_panic(p_s_sb, | |
2122 | "jmacd-5: tb_buffer_sanity_check(): buffer has wrong blocksize %s[%d] (%b)\n", | |
2123 | descr, level, p_s_bh); | |
1da177e4 LT |
2124 | } |
2125 | ||
bd4c625c LT |
2126 | if (p_s_bh->b_blocknr > SB_BLOCK_COUNT(p_s_sb)) { |
2127 | reiserfs_panic(p_s_sb, | |
2128 | "jmacd-6: tb_buffer_sanity_check(): buffer block number too high %s[%d] (%b)\n", | |
2129 | descr, level, p_s_bh); | |
1da177e4 | 2130 | } |
bd4c625c LT |
2131 | } |
2132 | } | |
2133 | #else | |
2134 | static void tb_buffer_sanity_check(struct super_block *p_s_sb, | |
2135 | struct buffer_head *p_s_bh, | |
2136 | const char *descr, int level) | |
2137 | {; | |
2138 | } | |
2139 | #endif | |
1da177e4 | 2140 | |
bd4c625c LT |
2141 | static int clear_all_dirty_bits(struct super_block *s, struct buffer_head *bh) |
2142 | { | |
2143 | return reiserfs_prepare_for_journal(s, bh, 0); | |
2144 | } | |
1da177e4 | 2145 | |
bd4c625c LT |
2146 | static int wait_tb_buffers_until_unlocked(struct tree_balance *p_s_tb) |
2147 | { | |
2148 | struct buffer_head *locked; | |
2149 | #ifdef CONFIG_REISERFS_CHECK | |
2150 | int repeat_counter = 0; | |
2151 | #endif | |
2152 | int i; | |
1da177e4 | 2153 | |
bd4c625c | 2154 | do { |
1da177e4 | 2155 | |
bd4c625c LT |
2156 | locked = NULL; |
2157 | ||
2158 | for (i = p_s_tb->tb_path->path_length; | |
2159 | !locked && i > ILLEGAL_PATH_ELEMENT_OFFSET; i--) { | |
2160 | if (PATH_OFFSET_PBUFFER(p_s_tb->tb_path, i)) { | |
2161 | /* if I understand correctly, we can only be sure the last buffer | |
2162 | ** in the path is in the tree --clm | |
2163 | */ | |
2164 | #ifdef CONFIG_REISERFS_CHECK | |
2165 | if (PATH_PLAST_BUFFER(p_s_tb->tb_path) == | |
2166 | PATH_OFFSET_PBUFFER(p_s_tb->tb_path, i)) { | |
2167 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2168 | PATH_OFFSET_PBUFFER | |
2169 | (p_s_tb->tb_path, | |
2170 | i), "S", | |
2171 | p_s_tb->tb_path-> | |
2172 | path_length - i); | |
2173 | } | |
2174 | #endif | |
2175 | if (!clear_all_dirty_bits(p_s_tb->tb_sb, | |
2176 | PATH_OFFSET_PBUFFER | |
2177 | (p_s_tb->tb_path, | |
2178 | i))) { | |
2179 | locked = | |
2180 | PATH_OFFSET_PBUFFER(p_s_tb->tb_path, | |
2181 | i); | |
2182 | } | |
2183 | } | |
1da177e4 LT |
2184 | } |
2185 | ||
bd4c625c LT |
2186 | for (i = 0; !locked && i < MAX_HEIGHT && p_s_tb->insert_size[i]; |
2187 | i++) { | |
2188 | ||
2189 | if (p_s_tb->lnum[i]) { | |
2190 | ||
2191 | if (p_s_tb->L[i]) { | |
2192 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2193 | p_s_tb->L[i], | |
2194 | "L", i); | |
2195 | if (!clear_all_dirty_bits | |
2196 | (p_s_tb->tb_sb, p_s_tb->L[i])) | |
2197 | locked = p_s_tb->L[i]; | |
2198 | } | |
2199 | ||
2200 | if (!locked && p_s_tb->FL[i]) { | |
2201 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2202 | p_s_tb->FL[i], | |
2203 | "FL", i); | |
2204 | if (!clear_all_dirty_bits | |
2205 | (p_s_tb->tb_sb, p_s_tb->FL[i])) | |
2206 | locked = p_s_tb->FL[i]; | |
2207 | } | |
2208 | ||
2209 | if (!locked && p_s_tb->CFL[i]) { | |
2210 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2211 | p_s_tb->CFL[i], | |
2212 | "CFL", i); | |
2213 | if (!clear_all_dirty_bits | |
2214 | (p_s_tb->tb_sb, p_s_tb->CFL[i])) | |
2215 | locked = p_s_tb->CFL[i]; | |
2216 | } | |
2217 | ||
2218 | } | |
2219 | ||
2220 | if (!locked && (p_s_tb->rnum[i])) { | |
2221 | ||
2222 | if (p_s_tb->R[i]) { | |
2223 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2224 | p_s_tb->R[i], | |
2225 | "R", i); | |
2226 | if (!clear_all_dirty_bits | |
2227 | (p_s_tb->tb_sb, p_s_tb->R[i])) | |
2228 | locked = p_s_tb->R[i]; | |
2229 | } | |
2230 | ||
2231 | if (!locked && p_s_tb->FR[i]) { | |
2232 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2233 | p_s_tb->FR[i], | |
2234 | "FR", i); | |
2235 | if (!clear_all_dirty_bits | |
2236 | (p_s_tb->tb_sb, p_s_tb->FR[i])) | |
2237 | locked = p_s_tb->FR[i]; | |
2238 | } | |
2239 | ||
2240 | if (!locked && p_s_tb->CFR[i]) { | |
2241 | tb_buffer_sanity_check(p_s_tb->tb_sb, | |
2242 | p_s_tb->CFR[i], | |
2243 | "CFR", i); | |
2244 | if (!clear_all_dirty_bits | |
2245 | (p_s_tb->tb_sb, p_s_tb->CFR[i])) | |
2246 | locked = p_s_tb->CFR[i]; | |
2247 | } | |
2248 | } | |
2249 | } | |
2250 | /* as far as I can tell, this is not required. The FEB list seems | |
2251 | ** to be full of newly allocated nodes, which will never be locked, | |
2252 | ** dirty, or anything else. | |
2253 | ** To be safe, I'm putting in the checks and waits in. For the moment, | |
2254 | ** they are needed to keep the code in journal.c from complaining | |
2255 | ** about the buffer. That code is inside CONFIG_REISERFS_CHECK as well. | |
2256 | ** --clm | |
2257 | */ | |
2258 | for (i = 0; !locked && i < MAX_FEB_SIZE; i++) { | |
2259 | if (p_s_tb->FEB[i]) { | |
2260 | if (!clear_all_dirty_bits | |
2261 | (p_s_tb->tb_sb, p_s_tb->FEB[i])) | |
2262 | locked = p_s_tb->FEB[i]; | |
2263 | } | |
1da177e4 | 2264 | } |
1da177e4 | 2265 | |
bd4c625c | 2266 | if (locked) { |
1da177e4 | 2267 | #ifdef CONFIG_REISERFS_CHECK |
bd4c625c LT |
2268 | repeat_counter++; |
2269 | if ((repeat_counter % 10000) == 0) { | |
2270 | reiserfs_warning(p_s_tb->tb_sb, | |
2271 | "wait_tb_buffers_until_released(): too many " | |
2272 | "iterations waiting for buffer to unlock " | |
2273 | "(%b)", locked); | |
2274 | ||
2275 | /* Don't loop forever. Try to recover from possible error. */ | |
2276 | ||
2277 | return (FILESYSTEM_CHANGED_TB(p_s_tb)) ? | |
2278 | REPEAT_SEARCH : CARRY_ON; | |
2279 | } | |
1da177e4 | 2280 | #endif |
bd4c625c LT |
2281 | __wait_on_buffer(locked); |
2282 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { | |
2283 | return REPEAT_SEARCH; | |
2284 | } | |
2285 | } | |
1da177e4 | 2286 | |
bd4c625c | 2287 | } while (locked); |
1da177e4 | 2288 | |
bd4c625c | 2289 | return CARRY_ON; |
1da177e4 LT |
2290 | } |
2291 | ||
1da177e4 LT |
2292 | /* Prepare for balancing, that is |
2293 | * get all necessary parents, and neighbors; | |
2294 | * analyze what and where should be moved; | |
2295 | * get sufficient number of new nodes; | |
2296 | * Balancing will start only after all resources will be collected at a time. | |
2297 | * | |
2298 | * When ported to SMP kernels, only at the last moment after all needed nodes | |
2299 | * are collected in cache, will the resources be locked using the usual | |
2300 | * textbook ordered lock acquisition algorithms. Note that ensuring that | |
2301 | * this code neither write locks what it does not need to write lock nor locks out of order | |
2302 | * will be a pain in the butt that could have been avoided. Grumble grumble. -Hans | |
2303 | * | |
2304 | * fix is meant in the sense of render unchanging | |
2305 | * | |
2306 | * Latency might be improved by first gathering a list of what buffers are needed | |
2307 | * and then getting as many of them in parallel as possible? -Hans | |
2308 | * | |
2309 | * Parameters: | |
2310 | * op_mode i - insert, d - delete, c - cut (truncate), p - paste (append) | |
2311 | * tb tree_balance structure; | |
2312 | * inum item number in S[h]; | |
2313 | * pos_in_item - comment this if you can | |
2314 | * ins_ih & ins_sd are used when inserting | |
2315 | * Returns: 1 - schedule occurred while the function worked; | |
2316 | * 0 - schedule didn't occur while the function worked; | |
2317 | * -1 - if no_disk_space | |
2318 | */ | |
2319 | ||
bd4c625c LT |
2320 | int fix_nodes(int n_op_mode, struct tree_balance *p_s_tb, struct item_head *p_s_ins_ih, // item head of item being inserted |
2321 | const void *data // inserted item or data to be pasted | |
2322 | ) | |
2323 | { | |
2324 | int n_ret_value, n_h, n_item_num = PATH_LAST_POSITION(p_s_tb->tb_path); | |
2325 | int n_pos_in_item; | |
1da177e4 | 2326 | |
bd4c625c LT |
2327 | /* we set wait_tb_buffers_run when we have to restore any dirty bits cleared |
2328 | ** during wait_tb_buffers_run | |
2329 | */ | |
2330 | int wait_tb_buffers_run = 0; | |
2331 | struct buffer_head *p_s_tbS0 = PATH_PLAST_BUFFER(p_s_tb->tb_path); | |
1da177e4 | 2332 | |
bd4c625c LT |
2333 | ++REISERFS_SB(p_s_tb->tb_sb)->s_fix_nodes; |
2334 | ||
2335 | n_pos_in_item = p_s_tb->tb_path->pos_in_item; | |
2336 | ||
2337 | p_s_tb->fs_gen = get_generation(p_s_tb->tb_sb); | |
1da177e4 | 2338 | |
bd4c625c LT |
2339 | /* we prepare and log the super here so it will already be in the |
2340 | ** transaction when do_balance needs to change it. | |
2341 | ** This way do_balance won't have to schedule when trying to prepare | |
2342 | ** the super for logging | |
2343 | */ | |
2344 | reiserfs_prepare_for_journal(p_s_tb->tb_sb, | |
2345 | SB_BUFFER_WITH_SB(p_s_tb->tb_sb), 1); | |
2346 | journal_mark_dirty(p_s_tb->transaction_handle, p_s_tb->tb_sb, | |
2347 | SB_BUFFER_WITH_SB(p_s_tb->tb_sb)); | |
2348 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) | |
2349 | return REPEAT_SEARCH; | |
1da177e4 | 2350 | |
bd4c625c LT |
2351 | /* if it possible in indirect_to_direct conversion */ |
2352 | if (buffer_locked(p_s_tbS0)) { | |
2353 | __wait_on_buffer(p_s_tbS0); | |
2354 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) | |
2355 | return REPEAT_SEARCH; | |
2356 | } | |
2357 | #ifdef CONFIG_REISERFS_CHECK | |
2358 | if (cur_tb) { | |
2359 | print_cur_tb("fix_nodes"); | |
2360 | reiserfs_panic(p_s_tb->tb_sb, | |
2361 | "PAP-8305: fix_nodes: there is pending do_balance"); | |
2362 | } | |
1da177e4 | 2363 | |
bd4c625c LT |
2364 | if (!buffer_uptodate(p_s_tbS0) || !B_IS_IN_TREE(p_s_tbS0)) { |
2365 | reiserfs_panic(p_s_tb->tb_sb, | |
2366 | "PAP-8320: fix_nodes: S[0] (%b %z) is not uptodate " | |
2367 | "at the beginning of fix_nodes or not in tree (mode %c)", | |
2368 | p_s_tbS0, p_s_tbS0, n_op_mode); | |
1da177e4 LT |
2369 | } |
2370 | ||
bd4c625c LT |
2371 | /* Check parameters. */ |
2372 | switch (n_op_mode) { | |
2373 | case M_INSERT: | |
2374 | if (n_item_num <= 0 || n_item_num > B_NR_ITEMS(p_s_tbS0)) | |
2375 | reiserfs_panic(p_s_tb->tb_sb, | |
2376 | "PAP-8330: fix_nodes: Incorrect item number %d (in S0 - %d) in case of insert", | |
2377 | n_item_num, B_NR_ITEMS(p_s_tbS0)); | |
2378 | break; | |
2379 | case M_PASTE: | |
2380 | case M_DELETE: | |
2381 | case M_CUT: | |
2382 | if (n_item_num < 0 || n_item_num >= B_NR_ITEMS(p_s_tbS0)) { | |
2383 | print_block(p_s_tbS0, 0, -1, -1); | |
2384 | reiserfs_panic(p_s_tb->tb_sb, | |
2385 | "PAP-8335: fix_nodes: Incorrect item number(%d); mode = %c insert_size = %d\n", | |
2386 | n_item_num, n_op_mode, | |
2387 | p_s_tb->insert_size[0]); | |
1da177e4 | 2388 | } |
1da177e4 | 2389 | break; |
bd4c625c LT |
2390 | default: |
2391 | reiserfs_panic(p_s_tb->tb_sb, | |
2392 | "PAP-8340: fix_nodes: Incorrect mode of operation"); | |
1da177e4 | 2393 | } |
bd4c625c | 2394 | #endif |
1da177e4 | 2395 | |
bd4c625c LT |
2396 | if (get_mem_for_virtual_node(p_s_tb) == REPEAT_SEARCH) |
2397 | // FIXME: maybe -ENOMEM when tb->vn_buf == 0? Now just repeat | |
2398 | return REPEAT_SEARCH; | |
1da177e4 | 2399 | |
bd4c625c LT |
2400 | /* Starting from the leaf level; for all levels n_h of the tree. */ |
2401 | for (n_h = 0; n_h < MAX_HEIGHT && p_s_tb->insert_size[n_h]; n_h++) { | |
2402 | if ((n_ret_value = get_direct_parent(p_s_tb, n_h)) != CARRY_ON) { | |
2403 | goto repeat; | |
2404 | } | |
1da177e4 | 2405 | |
bd4c625c LT |
2406 | if ((n_ret_value = |
2407 | check_balance(n_op_mode, p_s_tb, n_h, n_item_num, | |
2408 | n_pos_in_item, p_s_ins_ih, | |
2409 | data)) != CARRY_ON) { | |
2410 | if (n_ret_value == NO_BALANCING_NEEDED) { | |
2411 | /* No balancing for higher levels needed. */ | |
2412 | if ((n_ret_value = | |
2413 | get_neighbors(p_s_tb, n_h)) != CARRY_ON) { | |
2414 | goto repeat; | |
2415 | } | |
2416 | if (n_h != MAX_HEIGHT - 1) | |
2417 | p_s_tb->insert_size[n_h + 1] = 0; | |
2418 | /* ok, analysis and resource gathering are complete */ | |
2419 | break; | |
2420 | } | |
2421 | goto repeat; | |
2422 | } | |
1da177e4 | 2423 | |
bd4c625c LT |
2424 | if ((n_ret_value = get_neighbors(p_s_tb, n_h)) != CARRY_ON) { |
2425 | goto repeat; | |
1da177e4 | 2426 | } |
bd4c625c LT |
2427 | |
2428 | if ((n_ret_value = get_empty_nodes(p_s_tb, n_h)) != CARRY_ON) { | |
2429 | goto repeat; /* No disk space, or schedule occurred and | |
2430 | analysis may be invalid and needs to be redone. */ | |
2431 | } | |
2432 | ||
2433 | if (!PATH_H_PBUFFER(p_s_tb->tb_path, n_h)) { | |
2434 | /* We have a positive insert size but no nodes exist on this | |
2435 | level, this means that we are creating a new root. */ | |
2436 | ||
2437 | RFALSE(p_s_tb->blknum[n_h] != 1, | |
2438 | "PAP-8350: creating new empty root"); | |
2439 | ||
2440 | if (n_h < MAX_HEIGHT - 1) | |
2441 | p_s_tb->insert_size[n_h + 1] = 0; | |
2442 | } else if (!PATH_H_PBUFFER(p_s_tb->tb_path, n_h + 1)) { | |
2443 | if (p_s_tb->blknum[n_h] > 1) { | |
2444 | /* The tree needs to be grown, so this node S[n_h] | |
2445 | which is the root node is split into two nodes, | |
2446 | and a new node (S[n_h+1]) will be created to | |
2447 | become the root node. */ | |
2448 | ||
2449 | RFALSE(n_h == MAX_HEIGHT - 1, | |
2450 | "PAP-8355: attempt to create too high of a tree"); | |
2451 | ||
2452 | p_s_tb->insert_size[n_h + 1] = | |
2453 | (DC_SIZE + | |
2454 | KEY_SIZE) * (p_s_tb->blknum[n_h] - 1) + | |
2455 | DC_SIZE; | |
2456 | } else if (n_h < MAX_HEIGHT - 1) | |
2457 | p_s_tb->insert_size[n_h + 1] = 0; | |
2458 | } else | |
2459 | p_s_tb->insert_size[n_h + 1] = | |
2460 | (DC_SIZE + KEY_SIZE) * (p_s_tb->blknum[n_h] - 1); | |
1da177e4 | 2461 | } |
1da177e4 | 2462 | |
bd4c625c LT |
2463 | if ((n_ret_value = wait_tb_buffers_until_unlocked(p_s_tb)) == CARRY_ON) { |
2464 | if (FILESYSTEM_CHANGED_TB(p_s_tb)) { | |
2465 | wait_tb_buffers_run = 1; | |
2466 | n_ret_value = REPEAT_SEARCH; | |
2467 | goto repeat; | |
2468 | } else { | |
2469 | return CARRY_ON; | |
2470 | } | |
1da177e4 | 2471 | } else { |
bd4c625c LT |
2472 | wait_tb_buffers_run = 1; |
2473 | goto repeat; | |
1da177e4 LT |
2474 | } |
2475 | ||
bd4c625c LT |
2476 | repeat: |
2477 | // fix_nodes was unable to perform its calculation due to | |
2478 | // filesystem got changed under us, lack of free disk space or i/o | |
2479 | // failure. If the first is the case - the search will be | |
2480 | // repeated. For now - free all resources acquired so far except | |
2481 | // for the new allocated nodes | |
2482 | { | |
2483 | int i; | |
2484 | ||
2485 | /* Release path buffers. */ | |
2486 | if (wait_tb_buffers_run) { | |
2487 | pathrelse_and_restore(p_s_tb->tb_sb, p_s_tb->tb_path); | |
2488 | } else { | |
2489 | pathrelse(p_s_tb->tb_path); | |
2490 | } | |
2491 | /* brelse all resources collected for balancing */ | |
2492 | for (i = 0; i < MAX_HEIGHT; i++) { | |
2493 | if (wait_tb_buffers_run) { | |
2494 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2495 | p_s_tb->L[i]); | |
2496 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2497 | p_s_tb->R[i]); | |
2498 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2499 | p_s_tb->FL[i]); | |
2500 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2501 | p_s_tb->FR[i]); | |
2502 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2503 | p_s_tb-> | |
2504 | CFL[i]); | |
2505 | reiserfs_restore_prepared_buffer(p_s_tb->tb_sb, | |
2506 | p_s_tb-> | |
2507 | CFR[i]); | |
2508 | } | |
2509 | ||
2510 | brelse(p_s_tb->L[i]); | |
2511 | p_s_tb->L[i] = NULL; | |
2512 | brelse(p_s_tb->R[i]); | |
2513 | p_s_tb->R[i] = NULL; | |
2514 | brelse(p_s_tb->FL[i]); | |
2515 | p_s_tb->FL[i] = NULL; | |
2516 | brelse(p_s_tb->FR[i]); | |
2517 | p_s_tb->FR[i] = NULL; | |
2518 | brelse(p_s_tb->CFL[i]); | |
2519 | p_s_tb->CFL[i] = NULL; | |
2520 | brelse(p_s_tb->CFR[i]); | |
2521 | p_s_tb->CFR[i] = NULL; | |
2522 | } | |
2523 | ||
2524 | if (wait_tb_buffers_run) { | |
2525 | for (i = 0; i < MAX_FEB_SIZE; i++) { | |
2526 | if (p_s_tb->FEB[i]) { | |
2527 | reiserfs_restore_prepared_buffer | |
2528 | (p_s_tb->tb_sb, p_s_tb->FEB[i]); | |
2529 | } | |
2530 | } | |
1da177e4 | 2531 | } |
bd4c625c | 2532 | return n_ret_value; |
1da177e4 | 2533 | } |
1da177e4 LT |
2534 | |
2535 | } | |
2536 | ||
1da177e4 LT |
2537 | /* Anatoly will probably forgive me renaming p_s_tb to tb. I just |
2538 | wanted to make lines shorter */ | |
bd4c625c | 2539 | void unfix_nodes(struct tree_balance *tb) |
1da177e4 | 2540 | { |
bd4c625c | 2541 | int i; |
1da177e4 | 2542 | |
bd4c625c LT |
2543 | /* Release path buffers. */ |
2544 | pathrelse_and_restore(tb->tb_sb, tb->tb_path); | |
1da177e4 | 2545 | |
bd4c625c LT |
2546 | /* brelse all resources collected for balancing */ |
2547 | for (i = 0; i < MAX_HEIGHT; i++) { | |
2548 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->L[i]); | |
2549 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->R[i]); | |
2550 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FL[i]); | |
2551 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->FR[i]); | |
2552 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFL[i]); | |
2553 | reiserfs_restore_prepared_buffer(tb->tb_sb, tb->CFR[i]); | |
2554 | ||
2555 | brelse(tb->L[i]); | |
2556 | brelse(tb->R[i]); | |
2557 | brelse(tb->FL[i]); | |
2558 | brelse(tb->FR[i]); | |
2559 | brelse(tb->CFL[i]); | |
2560 | brelse(tb->CFR[i]); | |
2561 | } | |
1da177e4 | 2562 | |
bd4c625c LT |
2563 | /* deal with list of allocated (used and unused) nodes */ |
2564 | for (i = 0; i < MAX_FEB_SIZE; i++) { | |
2565 | if (tb->FEB[i]) { | |
2566 | b_blocknr_t blocknr = tb->FEB[i]->b_blocknr; | |
2567 | /* de-allocated block which was not used by balancing and | |
2568 | bforget about buffer for it */ | |
2569 | brelse(tb->FEB[i]); | |
2570 | reiserfs_free_block(tb->transaction_handle, NULL, | |
2571 | blocknr, 0); | |
2572 | } | |
2573 | if (tb->used[i]) { | |
2574 | /* release used as new nodes including a new root */ | |
2575 | brelse(tb->used[i]); | |
2576 | } | |
2577 | } | |
1da177e4 | 2578 | |
d739b42b | 2579 | kfree(tb->vn_buf); |
1da177e4 | 2580 | |
bd4c625c | 2581 | } |