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Linux/fs/nilfs2/btree.c

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  1 /*
  2  * btree.c - NILFS B-tree.
  3  *
  4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License as published by
  8  * the Free Software Foundation; either version 2 of the License, or
  9  * (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public License
 17  * along with this program; if not, write to the Free Software
 18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 19  *
 20  * Written by Koji Sato <koji@osrg.net>.
 21  */
 22 
 23 #include <linux/slab.h>
 24 #include <linux/string.h>
 25 #include <linux/errno.h>
 26 #include <linux/pagevec.h>
 27 #include "nilfs.h"
 28 #include "page.h"
 29 #include "btnode.h"
 30 #include "btree.h"
 31 #include "alloc.h"
 32 #include "dat.h"
 33 
 34 static void __nilfs_btree_init(struct nilfs_bmap *bmap);
 35 
 36 static struct nilfs_btree_path *nilfs_btree_alloc_path(void)
 37 {
 38         struct nilfs_btree_path *path;
 39         int level = NILFS_BTREE_LEVEL_DATA;
 40 
 41         path = kmem_cache_alloc(nilfs_btree_path_cache, GFP_NOFS);
 42         if (path == NULL)
 43                 goto out;
 44 
 45         for (; level < NILFS_BTREE_LEVEL_MAX; level++) {
 46                 path[level].bp_bh = NULL;
 47                 path[level].bp_sib_bh = NULL;
 48                 path[level].bp_index = 0;
 49                 path[level].bp_oldreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
 50                 path[level].bp_newreq.bpr_ptr = NILFS_BMAP_INVALID_PTR;
 51                 path[level].bp_op = NULL;
 52         }
 53 
 54 out:
 55         return path;
 56 }
 57 
 58 static void nilfs_btree_free_path(struct nilfs_btree_path *path)
 59 {
 60         int level = NILFS_BTREE_LEVEL_DATA;
 61 
 62         for (; level < NILFS_BTREE_LEVEL_MAX; level++)
 63                 brelse(path[level].bp_bh);
 64 
 65         kmem_cache_free(nilfs_btree_path_cache, path);
 66 }
 67 
 68 /*
 69  * B-tree node operations
 70  */
 71 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
 72                                      __u64 ptr, struct buffer_head **bhp)
 73 {
 74         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
 75         struct buffer_head *bh;
 76 
 77         bh = nilfs_btnode_create_block(btnc, ptr);
 78         if (!bh)
 79                 return -ENOMEM;
 80 
 81         set_buffer_nilfs_volatile(bh);
 82         *bhp = bh;
 83         return 0;
 84 }
 85 
 86 static int nilfs_btree_node_get_flags(const struct nilfs_btree_node *node)
 87 {
 88         return node->bn_flags;
 89 }
 90 
 91 static void
 92 nilfs_btree_node_set_flags(struct nilfs_btree_node *node, int flags)
 93 {
 94         node->bn_flags = flags;
 95 }
 96 
 97 static int nilfs_btree_node_root(const struct nilfs_btree_node *node)
 98 {
 99         return nilfs_btree_node_get_flags(node) & NILFS_BTREE_NODE_ROOT;
100 }
101 
102 static int nilfs_btree_node_get_level(const struct nilfs_btree_node *node)
103 {
104         return node->bn_level;
105 }
106 
107 static void
108 nilfs_btree_node_set_level(struct nilfs_btree_node *node, int level)
109 {
110         node->bn_level = level;
111 }
112 
113 static int nilfs_btree_node_get_nchildren(const struct nilfs_btree_node *node)
114 {
115         return le16_to_cpu(node->bn_nchildren);
116 }
117 
118 static void
119 nilfs_btree_node_set_nchildren(struct nilfs_btree_node *node, int nchildren)
120 {
121         node->bn_nchildren = cpu_to_le16(nchildren);
122 }
123 
124 static int nilfs_btree_node_size(const struct nilfs_bmap *btree)
125 {
126         return 1 << btree->b_inode->i_blkbits;
127 }
128 
129 static int nilfs_btree_nchildren_per_block(const struct nilfs_bmap *btree)
130 {
131         return btree->b_nchildren_per_block;
132 }
133 
134 static __le64 *
135 nilfs_btree_node_dkeys(const struct nilfs_btree_node *node)
136 {
137         return (__le64 *)((char *)(node + 1) +
138                           (nilfs_btree_node_root(node) ?
139                            0 : NILFS_BTREE_NODE_EXTRA_PAD_SIZE));
140 }
141 
142 static __le64 *
143 nilfs_btree_node_dptrs(const struct nilfs_btree_node *node, int ncmax)
144 {
145         return (__le64 *)(nilfs_btree_node_dkeys(node) + ncmax);
146 }
147 
148 static __u64
149 nilfs_btree_node_get_key(const struct nilfs_btree_node *node, int index)
150 {
151         return le64_to_cpu(*(nilfs_btree_node_dkeys(node) + index));
152 }
153 
154 static void
155 nilfs_btree_node_set_key(struct nilfs_btree_node *node, int index, __u64 key)
156 {
157         *(nilfs_btree_node_dkeys(node) + index) = cpu_to_le64(key);
158 }
159 
160 static __u64
161 nilfs_btree_node_get_ptr(const struct nilfs_btree_node *node, int index,
162                          int ncmax)
163 {
164         return le64_to_cpu(*(nilfs_btree_node_dptrs(node, ncmax) + index));
165 }
166 
167 static void
168 nilfs_btree_node_set_ptr(struct nilfs_btree_node *node, int index, __u64 ptr,
169                          int ncmax)
170 {
171         *(nilfs_btree_node_dptrs(node, ncmax) + index) = cpu_to_le64(ptr);
172 }
173 
174 static void nilfs_btree_node_init(struct nilfs_btree_node *node, int flags,
175                                   int level, int nchildren, int ncmax,
176                                   const __u64 *keys, const __u64 *ptrs)
177 {
178         __le64 *dkeys;
179         __le64 *dptrs;
180         int i;
181 
182         nilfs_btree_node_set_flags(node, flags);
183         nilfs_btree_node_set_level(node, level);
184         nilfs_btree_node_set_nchildren(node, nchildren);
185 
186         dkeys = nilfs_btree_node_dkeys(node);
187         dptrs = nilfs_btree_node_dptrs(node, ncmax);
188         for (i = 0; i < nchildren; i++) {
189                 dkeys[i] = cpu_to_le64(keys[i]);
190                 dptrs[i] = cpu_to_le64(ptrs[i]);
191         }
192 }
193 
194 /* Assume the buffer heads corresponding to left and right are locked. */
195 static void nilfs_btree_node_move_left(struct nilfs_btree_node *left,
196                                        struct nilfs_btree_node *right,
197                                        int n, int lncmax, int rncmax)
198 {
199         __le64 *ldkeys, *rdkeys;
200         __le64 *ldptrs, *rdptrs;
201         int lnchildren, rnchildren;
202 
203         ldkeys = nilfs_btree_node_dkeys(left);
204         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
205         lnchildren = nilfs_btree_node_get_nchildren(left);
206 
207         rdkeys = nilfs_btree_node_dkeys(right);
208         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
209         rnchildren = nilfs_btree_node_get_nchildren(right);
210 
211         memcpy(ldkeys + lnchildren, rdkeys, n * sizeof(*rdkeys));
212         memcpy(ldptrs + lnchildren, rdptrs, n * sizeof(*rdptrs));
213         memmove(rdkeys, rdkeys + n, (rnchildren - n) * sizeof(*rdkeys));
214         memmove(rdptrs, rdptrs + n, (rnchildren - n) * sizeof(*rdptrs));
215 
216         lnchildren += n;
217         rnchildren -= n;
218         nilfs_btree_node_set_nchildren(left, lnchildren);
219         nilfs_btree_node_set_nchildren(right, rnchildren);
220 }
221 
222 /* Assume that the buffer heads corresponding to left and right are locked. */
223 static void nilfs_btree_node_move_right(struct nilfs_btree_node *left,
224                                         struct nilfs_btree_node *right,
225                                         int n, int lncmax, int rncmax)
226 {
227         __le64 *ldkeys, *rdkeys;
228         __le64 *ldptrs, *rdptrs;
229         int lnchildren, rnchildren;
230 
231         ldkeys = nilfs_btree_node_dkeys(left);
232         ldptrs = nilfs_btree_node_dptrs(left, lncmax);
233         lnchildren = nilfs_btree_node_get_nchildren(left);
234 
235         rdkeys = nilfs_btree_node_dkeys(right);
236         rdptrs = nilfs_btree_node_dptrs(right, rncmax);
237         rnchildren = nilfs_btree_node_get_nchildren(right);
238 
239         memmove(rdkeys + n, rdkeys, rnchildren * sizeof(*rdkeys));
240         memmove(rdptrs + n, rdptrs, rnchildren * sizeof(*rdptrs));
241         memcpy(rdkeys, ldkeys + lnchildren - n, n * sizeof(*rdkeys));
242         memcpy(rdptrs, ldptrs + lnchildren - n, n * sizeof(*rdptrs));
243 
244         lnchildren -= n;
245         rnchildren += n;
246         nilfs_btree_node_set_nchildren(left, lnchildren);
247         nilfs_btree_node_set_nchildren(right, rnchildren);
248 }
249 
250 /* Assume that the buffer head corresponding to node is locked. */
251 static void nilfs_btree_node_insert(struct nilfs_btree_node *node, int index,
252                                     __u64 key, __u64 ptr, int ncmax)
253 {
254         __le64 *dkeys;
255         __le64 *dptrs;
256         int nchildren;
257 
258         dkeys = nilfs_btree_node_dkeys(node);
259         dptrs = nilfs_btree_node_dptrs(node, ncmax);
260         nchildren = nilfs_btree_node_get_nchildren(node);
261         if (index < nchildren) {
262                 memmove(dkeys + index + 1, dkeys + index,
263                         (nchildren - index) * sizeof(*dkeys));
264                 memmove(dptrs + index + 1, dptrs + index,
265                         (nchildren - index) * sizeof(*dptrs));
266         }
267         dkeys[index] = cpu_to_le64(key);
268         dptrs[index] = cpu_to_le64(ptr);
269         nchildren++;
270         nilfs_btree_node_set_nchildren(node, nchildren);
271 }
272 
273 /* Assume that the buffer head corresponding to node is locked. */
274 static void nilfs_btree_node_delete(struct nilfs_btree_node *node, int index,
275                                     __u64 *keyp, __u64 *ptrp, int ncmax)
276 {
277         __u64 key;
278         __u64 ptr;
279         __le64 *dkeys;
280         __le64 *dptrs;
281         int nchildren;
282 
283         dkeys = nilfs_btree_node_dkeys(node);
284         dptrs = nilfs_btree_node_dptrs(node, ncmax);
285         key = le64_to_cpu(dkeys[index]);
286         ptr = le64_to_cpu(dptrs[index]);
287         nchildren = nilfs_btree_node_get_nchildren(node);
288         if (keyp != NULL)
289                 *keyp = key;
290         if (ptrp != NULL)
291                 *ptrp = ptr;
292 
293         if (index < nchildren - 1) {
294                 memmove(dkeys + index, dkeys + index + 1,
295                         (nchildren - index - 1) * sizeof(*dkeys));
296                 memmove(dptrs + index, dptrs + index + 1,
297                         (nchildren - index - 1) * sizeof(*dptrs));
298         }
299         nchildren--;
300         nilfs_btree_node_set_nchildren(node, nchildren);
301 }
302 
303 static int nilfs_btree_node_lookup(const struct nilfs_btree_node *node,
304                                    __u64 key, int *indexp)
305 {
306         __u64 nkey;
307         int index, low, high, s;
308 
309         /* binary search */
310         low = 0;
311         high = nilfs_btree_node_get_nchildren(node) - 1;
312         index = 0;
313         s = 0;
314         while (low <= high) {
315                 index = (low + high) / 2;
316                 nkey = nilfs_btree_node_get_key(node, index);
317                 if (nkey == key) {
318                         s = 0;
319                         goto out;
320                 } else if (nkey < key) {
321                         low = index + 1;
322                         s = -1;
323                 } else {
324                         high = index - 1;
325                         s = 1;
326                 }
327         }
328 
329         /* adjust index */
330         if (nilfs_btree_node_get_level(node) > NILFS_BTREE_LEVEL_NODE_MIN) {
331                 if (s > 0 && index > 0)
332                         index--;
333         } else if (s < 0)
334                 index++;
335 
336  out:
337         *indexp = index;
338 
339         return s == 0;
340 }
341 
342 /**
343  * nilfs_btree_node_broken - verify consistency of btree node
344  * @node: btree node block to be examined
345  * @size: node size (in bytes)
346  * @blocknr: block number
347  *
348  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
349  */
350 static int nilfs_btree_node_broken(const struct nilfs_btree_node *node,
351                                    size_t size, sector_t blocknr)
352 {
353         int level, flags, nchildren;
354         int ret = 0;
355 
356         level = nilfs_btree_node_get_level(node);
357         flags = nilfs_btree_node_get_flags(node);
358         nchildren = nilfs_btree_node_get_nchildren(node);
359 
360         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
361                      level >= NILFS_BTREE_LEVEL_MAX ||
362                      (flags & NILFS_BTREE_NODE_ROOT) ||
363                      nchildren < 0 ||
364                      nchildren > NILFS_BTREE_NODE_NCHILDREN_MAX(size))) {
365                 printk(KERN_CRIT "NILFS: bad btree node (blocknr=%llu): "
366                        "level = %d, flags = 0x%x, nchildren = %d\n",
367                        (unsigned long long)blocknr, level, flags, nchildren);
368                 ret = 1;
369         }
370         return ret;
371 }
372 
373 /**
374  * nilfs_btree_root_broken - verify consistency of btree root node
375  * @node: btree root node to be examined
376  * @ino: inode number
377  *
378  * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned.
379  */
380 static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
381                                    unsigned long ino)
382 {
383         int level, flags, nchildren;
384         int ret = 0;
385 
386         level = nilfs_btree_node_get_level(node);
387         flags = nilfs_btree_node_get_flags(node);
388         nchildren = nilfs_btree_node_get_nchildren(node);
389 
390         if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
391                      level >= NILFS_BTREE_LEVEL_MAX ||
392                      nchildren < 0 ||
393                      nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
394                 pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n",
395                         ino, level, flags, nchildren);
396                 ret = 1;
397         }
398         return ret;
399 }
400 
401 int nilfs_btree_broken_node_block(struct buffer_head *bh)
402 {
403         int ret;
404 
405         if (buffer_nilfs_checked(bh))
406                 return 0;
407 
408         ret = nilfs_btree_node_broken((struct nilfs_btree_node *)bh->b_data,
409                                        bh->b_size, bh->b_blocknr);
410         if (likely(!ret))
411                 set_buffer_nilfs_checked(bh);
412         return ret;
413 }
414 
415 static struct nilfs_btree_node *
416 nilfs_btree_get_root(const struct nilfs_bmap *btree)
417 {
418         return (struct nilfs_btree_node *)btree->b_u.u_data;
419 }
420 
421 static struct nilfs_btree_node *
422 nilfs_btree_get_nonroot_node(const struct nilfs_btree_path *path, int level)
423 {
424         return (struct nilfs_btree_node *)path[level].bp_bh->b_data;
425 }
426 
427 static struct nilfs_btree_node *
428 nilfs_btree_get_sib_node(const struct nilfs_btree_path *path, int level)
429 {
430         return (struct nilfs_btree_node *)path[level].bp_sib_bh->b_data;
431 }
432 
433 static int nilfs_btree_height(const struct nilfs_bmap *btree)
434 {
435         return nilfs_btree_node_get_level(nilfs_btree_get_root(btree)) + 1;
436 }
437 
438 static struct nilfs_btree_node *
439 nilfs_btree_get_node(const struct nilfs_bmap *btree,
440                      const struct nilfs_btree_path *path,
441                      int level, int *ncmaxp)
442 {
443         struct nilfs_btree_node *node;
444 
445         if (level == nilfs_btree_height(btree) - 1) {
446                 node = nilfs_btree_get_root(btree);
447                 *ncmaxp = NILFS_BTREE_ROOT_NCHILDREN_MAX;
448         } else {
449                 node = nilfs_btree_get_nonroot_node(path, level);
450                 *ncmaxp = nilfs_btree_nchildren_per_block(btree);
451         }
452         return node;
453 }
454 
455 static int
456 nilfs_btree_bad_node(struct nilfs_btree_node *node, int level)
457 {
458         if (unlikely(nilfs_btree_node_get_level(node) != level)) {
459                 dump_stack();
460                 printk(KERN_CRIT "NILFS: btree level mismatch: %d != %d\n",
461                        nilfs_btree_node_get_level(node), level);
462                 return 1;
463         }
464         return 0;
465 }
466 
467 struct nilfs_btree_readahead_info {
468         struct nilfs_btree_node *node;  /* parent node */
469         int max_ra_blocks;              /* max nof blocks to read ahead */
470         int index;                      /* current index on the parent node */
471         int ncmax;                      /* nof children in the parent node */
472 };
473 
474 static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
475                                    struct buffer_head **bhp,
476                                    const struct nilfs_btree_readahead_info *ra)
477 {
478         struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
479         struct buffer_head *bh, *ra_bh;
480         sector_t submit_ptr = 0;
481         int ret;
482 
483         ret = nilfs_btnode_submit_block(btnc, ptr, 0, READ, &bh, &submit_ptr);
484         if (ret) {
485                 if (ret != -EEXIST)
486                         return ret;
487                 goto out_check;
488         }
489 
490         if (ra) {
491                 int i, n;
492                 __u64 ptr2;
493 
494                 /* read ahead sibling nodes */
495                 for (n = ra->max_ra_blocks, i = ra->index + 1;
496                      n > 0 && i < ra->ncmax; n--, i++) {
497                         ptr2 = nilfs_btree_node_get_ptr(ra->node, i, ra->ncmax);
498 
499                         ret = nilfs_btnode_submit_block(btnc, ptr2, 0, READA,
500                                                         &ra_bh, &submit_ptr);
501                         if (likely(!ret || ret == -EEXIST))
502                                 brelse(ra_bh);
503                         else if (ret != -EBUSY)
504                                 break;
505                         if (!buffer_locked(bh))
506                                 goto out_no_wait;
507                 }
508         }
509 
510         wait_on_buffer(bh);
511 
512  out_no_wait:
513         if (!buffer_uptodate(bh)) {
514                 brelse(bh);
515                 return -EIO;
516         }
517 
518  out_check:
519         if (nilfs_btree_broken_node_block(bh)) {
520                 clear_buffer_uptodate(bh);
521                 brelse(bh);
522                 return -EINVAL;
523         }
524 
525         *bhp = bh;
526         return 0;
527 }
528 
529 static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
530                                    struct buffer_head **bhp)
531 {
532         return __nilfs_btree_get_block(btree, ptr, bhp, NULL);
533 }
534 
535 static int nilfs_btree_do_lookup(const struct nilfs_bmap *btree,
536                                  struct nilfs_btree_path *path,
537                                  __u64 key, __u64 *ptrp, int minlevel,
538                                  int readahead)
539 {
540         struct nilfs_btree_node *node;
541         struct nilfs_btree_readahead_info p, *ra;
542         __u64 ptr;
543         int level, index, found, ncmax, ret;
544 
545         node = nilfs_btree_get_root(btree);
546         level = nilfs_btree_node_get_level(node);
547         if (level < minlevel || nilfs_btree_node_get_nchildren(node) <= 0)
548                 return -ENOENT;
549 
550         found = nilfs_btree_node_lookup(node, key, &index);
551         ptr = nilfs_btree_node_get_ptr(node, index,
552                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
553         path[level].bp_bh = NULL;
554         path[level].bp_index = index;
555 
556         ncmax = nilfs_btree_nchildren_per_block(btree);
557 
558         while (--level >= minlevel) {
559                 ra = NULL;
560                 if (level == NILFS_BTREE_LEVEL_NODE_MIN && readahead) {
561                         p.node = nilfs_btree_get_node(btree, path, level + 1,
562                                                       &p.ncmax);
563                         p.index = index;
564                         p.max_ra_blocks = 7;
565                         ra = &p;
566                 }
567                 ret = __nilfs_btree_get_block(btree, ptr, &path[level].bp_bh,
568                                               ra);
569                 if (ret < 0)
570                         return ret;
571 
572                 node = nilfs_btree_get_nonroot_node(path, level);
573                 if (nilfs_btree_bad_node(node, level))
574                         return -EINVAL;
575                 if (!found)
576                         found = nilfs_btree_node_lookup(node, key, &index);
577                 else
578                         index = 0;
579                 if (index < ncmax) {
580                         ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
581                 } else {
582                         WARN_ON(found || level != NILFS_BTREE_LEVEL_NODE_MIN);
583                         /* insert */
584                         ptr = NILFS_BMAP_INVALID_PTR;
585                 }
586                 path[level].bp_index = index;
587         }
588         if (!found)
589                 return -ENOENT;
590 
591         if (ptrp != NULL)
592                 *ptrp = ptr;
593 
594         return 0;
595 }
596 
597 static int nilfs_btree_do_lookup_last(const struct nilfs_bmap *btree,
598                                       struct nilfs_btree_path *path,
599                                       __u64 *keyp, __u64 *ptrp)
600 {
601         struct nilfs_btree_node *node;
602         __u64 ptr;
603         int index, level, ncmax, ret;
604 
605         node = nilfs_btree_get_root(btree);
606         index = nilfs_btree_node_get_nchildren(node) - 1;
607         if (index < 0)
608                 return -ENOENT;
609         level = nilfs_btree_node_get_level(node);
610         ptr = nilfs_btree_node_get_ptr(node, index,
611                                        NILFS_BTREE_ROOT_NCHILDREN_MAX);
612         path[level].bp_bh = NULL;
613         path[level].bp_index = index;
614         ncmax = nilfs_btree_nchildren_per_block(btree);
615 
616         for (level--; level > 0; level--) {
617                 ret = nilfs_btree_get_block(btree, ptr, &path[level].bp_bh);
618                 if (ret < 0)
619                         return ret;
620                 node = nilfs_btree_get_nonroot_node(path, level);
621                 if (nilfs_btree_bad_node(node, level))
622                         return -EINVAL;
623                 index = nilfs_btree_node_get_nchildren(node) - 1;
624                 ptr = nilfs_btree_node_get_ptr(node, index, ncmax);
625                 path[level].bp_index = index;
626         }
627 
628         if (keyp != NULL)
629                 *keyp = nilfs_btree_node_get_key(node, index);
630         if (ptrp != NULL)
631                 *ptrp = ptr;
632 
633         return 0;
634 }
635 
636 /**
637  * nilfs_btree_get_next_key - get next valid key from btree path array
638  * @btree: bmap struct of btree
639  * @path: array of nilfs_btree_path struct
640  * @minlevel: start level
641  * @nextkey: place to store the next valid key
642  *
643  * Return Value: If a next key was found, 0 is returned. Otherwise,
644  * -ENOENT is returned.
645  */
646 static int nilfs_btree_get_next_key(const struct nilfs_bmap *btree,
647                                     const struct nilfs_btree_path *path,
648                                     int minlevel, __u64 *nextkey)
649 {
650         struct nilfs_btree_node *node;
651         int maxlevel = nilfs_btree_height(btree) - 1;
652         int index, next_adj, level;
653 
654         /* Next index is already set to bp_index for leaf nodes. */
655         next_adj = 0;
656         for (level = minlevel; level <= maxlevel; level++) {
657                 if (level == maxlevel)
658                         node = nilfs_btree_get_root(btree);
659                 else
660                         node = nilfs_btree_get_nonroot_node(path, level);
661 
662                 index = path[level].bp_index + next_adj;
663                 if (index < nilfs_btree_node_get_nchildren(node)) {
664                         /* Next key is in this node */
665                         *nextkey = nilfs_btree_node_get_key(node, index);
666                         return 0;
667                 }
668                 /* For non-leaf nodes, next index is stored at bp_index + 1. */
669                 next_adj = 1;
670         }
671         return -ENOENT;
672 }
673 
674 static int nilfs_btree_lookup(const struct nilfs_bmap *btree,
675                               __u64 key, int level, __u64 *ptrp)
676 {
677         struct nilfs_btree_path *path;
678         int ret;
679 
680         path = nilfs_btree_alloc_path();
681         if (path == NULL)
682                 return -ENOMEM;
683 
684         ret = nilfs_btree_do_lookup(btree, path, key, ptrp, level, 0);
685 
686         nilfs_btree_free_path(path);
687 
688         return ret;
689 }
690 
691 static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree,
692                                      __u64 key, __u64 *ptrp, unsigned maxblocks)
693 {
694         struct nilfs_btree_path *path;
695         struct nilfs_btree_node *node;
696         struct inode *dat = NULL;
697         __u64 ptr, ptr2;
698         sector_t blocknr;
699         int level = NILFS_BTREE_LEVEL_NODE_MIN;
700         int ret, cnt, index, maxlevel, ncmax;
701         struct nilfs_btree_readahead_info p;
702 
703         path = nilfs_btree_alloc_path();
704         if (path == NULL)
705                 return -ENOMEM;
706 
707         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level, 1);
708         if (ret < 0)
709                 goto out;
710 
711         if (NILFS_BMAP_USE_VBN(btree)) {
712                 dat = nilfs_bmap_get_dat(btree);
713                 ret = nilfs_dat_translate(dat, ptr, &blocknr);
714                 if (ret < 0)
715                         goto out;
716                 ptr = blocknr;
717         }
718         cnt = 1;
719         if (cnt == maxblocks)
720                 goto end;
721 
722         maxlevel = nilfs_btree_height(btree) - 1;
723         node = nilfs_btree_get_node(btree, path, level, &ncmax);
724         index = path[level].bp_index + 1;
725         for (;;) {
726                 while (index < nilfs_btree_node_get_nchildren(node)) {
727                         if (nilfs_btree_node_get_key(node, index) !=
728                             key + cnt)
729                                 goto end;
730                         ptr2 = nilfs_btree_node_get_ptr(node, index, ncmax);
731                         if (dat) {
732                                 ret = nilfs_dat_translate(dat, ptr2, &blocknr);
733                                 if (ret < 0)
734                                         goto out;
735                                 ptr2 = blocknr;
736                         }
737                         if (ptr2 != ptr + cnt || ++cnt == maxblocks)
738                                 goto end;
739                         index++;
740                         continue;
741                 }
742                 if (level == maxlevel)
743                         break;
744 
745                 /* look-up right sibling node */
746                 p.node = nilfs_btree_get_node(btree, path, level + 1, &p.ncmax);
747                 p.index = path[level + 1].bp_index + 1;
748                 p.max_ra_blocks = 7;
749                 if (p.index >= nilfs_btree_node_get_nchildren(p.node) ||
750                     nilfs_btree_node_get_key(p.node, p.index) != key + cnt)
751                         break;
752                 ptr2 = nilfs_btree_node_get_ptr(p.node, p.index, p.ncmax);
753                 path[level + 1].bp_index = p.index;
754 
755                 brelse(path[level].bp_bh);
756                 path[level].bp_bh = NULL;
757 
758                 ret = __nilfs_btree_get_block(btree, ptr2, &path[level].bp_bh,
759                                               &p);
760                 if (ret < 0)
761                         goto out;
762                 node = nilfs_btree_get_nonroot_node(path, level);
763                 ncmax = nilfs_btree_nchildren_per_block(btree);
764                 index = 0;
765                 path[level].bp_index = index;
766         }
767  end:
768         *ptrp = ptr;
769         ret = cnt;
770  out:
771         nilfs_btree_free_path(path);
772         return ret;
773 }
774 
775 static void nilfs_btree_promote_key(struct nilfs_bmap *btree,
776                                     struct nilfs_btree_path *path,
777                                     int level, __u64 key)
778 {
779         if (level < nilfs_btree_height(btree) - 1) {
780                 do {
781                         nilfs_btree_node_set_key(
782                                 nilfs_btree_get_nonroot_node(path, level),
783                                 path[level].bp_index, key);
784                         if (!buffer_dirty(path[level].bp_bh))
785                                 mark_buffer_dirty(path[level].bp_bh);
786                 } while ((path[level].bp_index == 0) &&
787                          (++level < nilfs_btree_height(btree) - 1));
788         }
789 
790         /* root */
791         if (level == nilfs_btree_height(btree) - 1) {
792                 nilfs_btree_node_set_key(nilfs_btree_get_root(btree),
793                                          path[level].bp_index, key);
794         }
795 }
796 
797 static void nilfs_btree_do_insert(struct nilfs_bmap *btree,
798                                   struct nilfs_btree_path *path,
799                                   int level, __u64 *keyp, __u64 *ptrp)
800 {
801         struct nilfs_btree_node *node;
802         int ncblk;
803 
804         if (level < nilfs_btree_height(btree) - 1) {
805                 node = nilfs_btree_get_nonroot_node(path, level);
806                 ncblk = nilfs_btree_nchildren_per_block(btree);
807                 nilfs_btree_node_insert(node, path[level].bp_index,
808                                         *keyp, *ptrp, ncblk);
809                 if (!buffer_dirty(path[level].bp_bh))
810                         mark_buffer_dirty(path[level].bp_bh);
811 
812                 if (path[level].bp_index == 0)
813                         nilfs_btree_promote_key(btree, path, level + 1,
814                                                 nilfs_btree_node_get_key(node,
815                                                                          0));
816         } else {
817                 node = nilfs_btree_get_root(btree);
818                 nilfs_btree_node_insert(node, path[level].bp_index,
819                                         *keyp, *ptrp,
820                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
821         }
822 }
823 
824 static void nilfs_btree_carry_left(struct nilfs_bmap *btree,
825                                    struct nilfs_btree_path *path,
826                                    int level, __u64 *keyp, __u64 *ptrp)
827 {
828         struct nilfs_btree_node *node, *left;
829         int nchildren, lnchildren, n, move, ncblk;
830 
831         node = nilfs_btree_get_nonroot_node(path, level);
832         left = nilfs_btree_get_sib_node(path, level);
833         nchildren = nilfs_btree_node_get_nchildren(node);
834         lnchildren = nilfs_btree_node_get_nchildren(left);
835         ncblk = nilfs_btree_nchildren_per_block(btree);
836         move = 0;
837 
838         n = (nchildren + lnchildren + 1) / 2 - lnchildren;
839         if (n > path[level].bp_index) {
840                 /* move insert point */
841                 n--;
842                 move = 1;
843         }
844 
845         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
846 
847         if (!buffer_dirty(path[level].bp_bh))
848                 mark_buffer_dirty(path[level].bp_bh);
849         if (!buffer_dirty(path[level].bp_sib_bh))
850                 mark_buffer_dirty(path[level].bp_sib_bh);
851 
852         nilfs_btree_promote_key(btree, path, level + 1,
853                                 nilfs_btree_node_get_key(node, 0));
854 
855         if (move) {
856                 brelse(path[level].bp_bh);
857                 path[level].bp_bh = path[level].bp_sib_bh;
858                 path[level].bp_sib_bh = NULL;
859                 path[level].bp_index += lnchildren;
860                 path[level + 1].bp_index--;
861         } else {
862                 brelse(path[level].bp_sib_bh);
863                 path[level].bp_sib_bh = NULL;
864                 path[level].bp_index -= n;
865         }
866 
867         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
868 }
869 
870 static void nilfs_btree_carry_right(struct nilfs_bmap *btree,
871                                     struct nilfs_btree_path *path,
872                                     int level, __u64 *keyp, __u64 *ptrp)
873 {
874         struct nilfs_btree_node *node, *right;
875         int nchildren, rnchildren, n, move, ncblk;
876 
877         node = nilfs_btree_get_nonroot_node(path, level);
878         right = nilfs_btree_get_sib_node(path, level);
879         nchildren = nilfs_btree_node_get_nchildren(node);
880         rnchildren = nilfs_btree_node_get_nchildren(right);
881         ncblk = nilfs_btree_nchildren_per_block(btree);
882         move = 0;
883 
884         n = (nchildren + rnchildren + 1) / 2 - rnchildren;
885         if (n > nchildren - path[level].bp_index) {
886                 /* move insert point */
887                 n--;
888                 move = 1;
889         }
890 
891         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
892 
893         if (!buffer_dirty(path[level].bp_bh))
894                 mark_buffer_dirty(path[level].bp_bh);
895         if (!buffer_dirty(path[level].bp_sib_bh))
896                 mark_buffer_dirty(path[level].bp_sib_bh);
897 
898         path[level + 1].bp_index++;
899         nilfs_btree_promote_key(btree, path, level + 1,
900                                 nilfs_btree_node_get_key(right, 0));
901         path[level + 1].bp_index--;
902 
903         if (move) {
904                 brelse(path[level].bp_bh);
905                 path[level].bp_bh = path[level].bp_sib_bh;
906                 path[level].bp_sib_bh = NULL;
907                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
908                 path[level + 1].bp_index++;
909         } else {
910                 brelse(path[level].bp_sib_bh);
911                 path[level].bp_sib_bh = NULL;
912         }
913 
914         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
915 }
916 
917 static void nilfs_btree_split(struct nilfs_bmap *btree,
918                               struct nilfs_btree_path *path,
919                               int level, __u64 *keyp, __u64 *ptrp)
920 {
921         struct nilfs_btree_node *node, *right;
922         int nchildren, n, move, ncblk;
923 
924         node = nilfs_btree_get_nonroot_node(path, level);
925         right = nilfs_btree_get_sib_node(path, level);
926         nchildren = nilfs_btree_node_get_nchildren(node);
927         ncblk = nilfs_btree_nchildren_per_block(btree);
928         move = 0;
929 
930         n = (nchildren + 1) / 2;
931         if (n > nchildren - path[level].bp_index) {
932                 n--;
933                 move = 1;
934         }
935 
936         nilfs_btree_node_move_right(node, right, n, ncblk, ncblk);
937 
938         if (!buffer_dirty(path[level].bp_bh))
939                 mark_buffer_dirty(path[level].bp_bh);
940         if (!buffer_dirty(path[level].bp_sib_bh))
941                 mark_buffer_dirty(path[level].bp_sib_bh);
942 
943         if (move) {
944                 path[level].bp_index -= nilfs_btree_node_get_nchildren(node);
945                 nilfs_btree_node_insert(right, path[level].bp_index,
946                                         *keyp, *ptrp, ncblk);
947 
948                 *keyp = nilfs_btree_node_get_key(right, 0);
949                 *ptrp = path[level].bp_newreq.bpr_ptr;
950 
951                 brelse(path[level].bp_bh);
952                 path[level].bp_bh = path[level].bp_sib_bh;
953                 path[level].bp_sib_bh = NULL;
954         } else {
955                 nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
956 
957                 *keyp = nilfs_btree_node_get_key(right, 0);
958                 *ptrp = path[level].bp_newreq.bpr_ptr;
959 
960                 brelse(path[level].bp_sib_bh);
961                 path[level].bp_sib_bh = NULL;
962         }
963 
964         path[level + 1].bp_index++;
965 }
966 
967 static void nilfs_btree_grow(struct nilfs_bmap *btree,
968                              struct nilfs_btree_path *path,
969                              int level, __u64 *keyp, __u64 *ptrp)
970 {
971         struct nilfs_btree_node *root, *child;
972         int n, ncblk;
973 
974         root = nilfs_btree_get_root(btree);
975         child = nilfs_btree_get_sib_node(path, level);
976         ncblk = nilfs_btree_nchildren_per_block(btree);
977 
978         n = nilfs_btree_node_get_nchildren(root);
979 
980         nilfs_btree_node_move_right(root, child, n,
981                                     NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
982         nilfs_btree_node_set_level(root, level + 1);
983 
984         if (!buffer_dirty(path[level].bp_sib_bh))
985                 mark_buffer_dirty(path[level].bp_sib_bh);
986 
987         path[level].bp_bh = path[level].bp_sib_bh;
988         path[level].bp_sib_bh = NULL;
989 
990         nilfs_btree_do_insert(btree, path, level, keyp, ptrp);
991 
992         *keyp = nilfs_btree_node_get_key(child, 0);
993         *ptrp = path[level].bp_newreq.bpr_ptr;
994 }
995 
996 static __u64 nilfs_btree_find_near(const struct nilfs_bmap *btree,
997                                    const struct nilfs_btree_path *path)
998 {
999         struct nilfs_btree_node *node;
1000         int level, ncmax;
1001 
1002         if (path == NULL)
1003                 return NILFS_BMAP_INVALID_PTR;
1004 
1005         /* left sibling */
1006         level = NILFS_BTREE_LEVEL_NODE_MIN;
1007         if (path[level].bp_index > 0) {
1008                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1009                 return nilfs_btree_node_get_ptr(node,
1010                                                 path[level].bp_index - 1,
1011                                                 ncmax);
1012         }
1013 
1014         /* parent */
1015         level = NILFS_BTREE_LEVEL_NODE_MIN + 1;
1016         if (level <= nilfs_btree_height(btree) - 1) {
1017                 node = nilfs_btree_get_node(btree, path, level, &ncmax);
1018                 return nilfs_btree_node_get_ptr(node, path[level].bp_index,
1019                                                 ncmax);
1020         }
1021 
1022         return NILFS_BMAP_INVALID_PTR;
1023 }
1024 
1025 static __u64 nilfs_btree_find_target_v(const struct nilfs_bmap *btree,
1026                                        const struct nilfs_btree_path *path,
1027                                        __u64 key)
1028 {
1029         __u64 ptr;
1030 
1031         ptr = nilfs_bmap_find_target_seq(btree, key);
1032         if (ptr != NILFS_BMAP_INVALID_PTR)
1033                 /* sequential access */
1034                 return ptr;
1035         else {
1036                 ptr = nilfs_btree_find_near(btree, path);
1037                 if (ptr != NILFS_BMAP_INVALID_PTR)
1038                         /* near */
1039                         return ptr;
1040         }
1041         /* block group */
1042         return nilfs_bmap_find_target_in_group(btree);
1043 }
1044 
1045 static int nilfs_btree_prepare_insert(struct nilfs_bmap *btree,
1046                                       struct nilfs_btree_path *path,
1047                                       int *levelp, __u64 key, __u64 ptr,
1048                                       struct nilfs_bmap_stats *stats)
1049 {
1050         struct buffer_head *bh;
1051         struct nilfs_btree_node *node, *parent, *sib;
1052         __u64 sibptr;
1053         int pindex, level, ncmax, ncblk, ret;
1054         struct inode *dat = NULL;
1055 
1056         stats->bs_nblocks = 0;
1057         level = NILFS_BTREE_LEVEL_DATA;
1058 
1059         /* allocate a new ptr for data block */
1060         if (NILFS_BMAP_USE_VBN(btree)) {
1061                 path[level].bp_newreq.bpr_ptr =
1062                         nilfs_btree_find_target_v(btree, path, key);
1063                 dat = nilfs_bmap_get_dat(btree);
1064         }
1065 
1066         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1067         if (ret < 0)
1068                 goto err_out_data;
1069 
1070         ncblk = nilfs_btree_nchildren_per_block(btree);
1071 
1072         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
1073              level < nilfs_btree_height(btree) - 1;
1074              level++) {
1075                 node = nilfs_btree_get_nonroot_node(path, level);
1076                 if (nilfs_btree_node_get_nchildren(node) < ncblk) {
1077                         path[level].bp_op = nilfs_btree_do_insert;
1078                         stats->bs_nblocks++;
1079                         goto out;
1080                 }
1081 
1082                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1083                 pindex = path[level + 1].bp_index;
1084 
1085                 /* left sibling */
1086                 if (pindex > 0) {
1087                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1088                                                           ncmax);
1089                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1090                         if (ret < 0)
1091                                 goto err_out_child_node;
1092                         sib = (struct nilfs_btree_node *)bh->b_data;
1093                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1094                                 path[level].bp_sib_bh = bh;
1095                                 path[level].bp_op = nilfs_btree_carry_left;
1096                                 stats->bs_nblocks++;
1097                                 goto out;
1098                         } else {
1099                                 brelse(bh);
1100                         }
1101                 }
1102 
1103                 /* right sibling */
1104                 if (pindex < nilfs_btree_node_get_nchildren(parent) - 1) {
1105                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1106                                                           ncmax);
1107                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1108                         if (ret < 0)
1109                                 goto err_out_child_node;
1110                         sib = (struct nilfs_btree_node *)bh->b_data;
1111                         if (nilfs_btree_node_get_nchildren(sib) < ncblk) {
1112                                 path[level].bp_sib_bh = bh;
1113                                 path[level].bp_op = nilfs_btree_carry_right;
1114                                 stats->bs_nblocks++;
1115                                 goto out;
1116                         } else {
1117                                 brelse(bh);
1118                         }
1119                 }
1120 
1121                 /* split */
1122                 path[level].bp_newreq.bpr_ptr =
1123                         path[level - 1].bp_newreq.bpr_ptr + 1;
1124                 ret = nilfs_bmap_prepare_alloc_ptr(btree,
1125                                                    &path[level].bp_newreq, dat);
1126                 if (ret < 0)
1127                         goto err_out_child_node;
1128                 ret = nilfs_btree_get_new_block(btree,
1129                                                 path[level].bp_newreq.bpr_ptr,
1130                                                 &bh);
1131                 if (ret < 0)
1132                         goto err_out_curr_node;
1133 
1134                 stats->bs_nblocks++;
1135 
1136                 sib = (struct nilfs_btree_node *)bh->b_data;
1137                 nilfs_btree_node_init(sib, 0, level, 0, ncblk, NULL, NULL);
1138                 path[level].bp_sib_bh = bh;
1139                 path[level].bp_op = nilfs_btree_split;
1140         }
1141 
1142         /* root */
1143         node = nilfs_btree_get_root(btree);
1144         if (nilfs_btree_node_get_nchildren(node) <
1145             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1146                 path[level].bp_op = nilfs_btree_do_insert;
1147                 stats->bs_nblocks++;
1148                 goto out;
1149         }
1150 
1151         /* grow */
1152         path[level].bp_newreq.bpr_ptr = path[level - 1].bp_newreq.bpr_ptr + 1;
1153         ret = nilfs_bmap_prepare_alloc_ptr(btree, &path[level].bp_newreq, dat);
1154         if (ret < 0)
1155                 goto err_out_child_node;
1156         ret = nilfs_btree_get_new_block(btree, path[level].bp_newreq.bpr_ptr,
1157                                         &bh);
1158         if (ret < 0)
1159                 goto err_out_curr_node;
1160 
1161         nilfs_btree_node_init((struct nilfs_btree_node *)bh->b_data,
1162                               0, level, 0, ncblk, NULL, NULL);
1163         path[level].bp_sib_bh = bh;
1164         path[level].bp_op = nilfs_btree_grow;
1165 
1166         level++;
1167         path[level].bp_op = nilfs_btree_do_insert;
1168 
1169         /* a newly-created node block and a data block are added */
1170         stats->bs_nblocks += 2;
1171 
1172         /* success */
1173  out:
1174         *levelp = level;
1175         return ret;
1176 
1177         /* error */
1178  err_out_curr_node:
1179         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1180  err_out_child_node:
1181         for (level--; level > NILFS_BTREE_LEVEL_DATA; level--) {
1182                 nilfs_btnode_delete(path[level].bp_sib_bh);
1183                 nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1184 
1185         }
1186 
1187         nilfs_bmap_abort_alloc_ptr(btree, &path[level].bp_newreq, dat);
1188  err_out_data:
1189         *levelp = level;
1190         stats->bs_nblocks = 0;
1191         return ret;
1192 }
1193 
1194 static void nilfs_btree_commit_insert(struct nilfs_bmap *btree,
1195                                       struct nilfs_btree_path *path,
1196                                       int maxlevel, __u64 key, __u64 ptr)
1197 {
1198         struct inode *dat = NULL;
1199         int level;
1200 
1201         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1202         ptr = path[NILFS_BTREE_LEVEL_DATA].bp_newreq.bpr_ptr;
1203         if (NILFS_BMAP_USE_VBN(btree)) {
1204                 nilfs_bmap_set_target_v(btree, key, ptr);
1205                 dat = nilfs_bmap_get_dat(btree);
1206         }
1207 
1208         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1209                 nilfs_bmap_commit_alloc_ptr(btree,
1210                                             &path[level - 1].bp_newreq, dat);
1211                 path[level].bp_op(btree, path, level, &key, &ptr);
1212         }
1213 
1214         if (!nilfs_bmap_dirty(btree))
1215                 nilfs_bmap_set_dirty(btree);
1216 }
1217 
1218 static int nilfs_btree_insert(struct nilfs_bmap *btree, __u64 key, __u64 ptr)
1219 {
1220         struct nilfs_btree_path *path;
1221         struct nilfs_bmap_stats stats;
1222         int level, ret;
1223 
1224         path = nilfs_btree_alloc_path();
1225         if (path == NULL)
1226                 return -ENOMEM;
1227 
1228         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1229                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1230         if (ret != -ENOENT) {
1231                 if (ret == 0)
1232                         ret = -EEXIST;
1233                 goto out;
1234         }
1235 
1236         ret = nilfs_btree_prepare_insert(btree, path, &level, key, ptr, &stats);
1237         if (ret < 0)
1238                 goto out;
1239         nilfs_btree_commit_insert(btree, path, level, key, ptr);
1240         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1241 
1242  out:
1243         nilfs_btree_free_path(path);
1244         return ret;
1245 }
1246 
1247 static void nilfs_btree_do_delete(struct nilfs_bmap *btree,
1248                                   struct nilfs_btree_path *path,
1249                                   int level, __u64 *keyp, __u64 *ptrp)
1250 {
1251         struct nilfs_btree_node *node;
1252         int ncblk;
1253 
1254         if (level < nilfs_btree_height(btree) - 1) {
1255                 node = nilfs_btree_get_nonroot_node(path, level);
1256                 ncblk = nilfs_btree_nchildren_per_block(btree);
1257                 nilfs_btree_node_delete(node, path[level].bp_index,
1258                                         keyp, ptrp, ncblk);
1259                 if (!buffer_dirty(path[level].bp_bh))
1260                         mark_buffer_dirty(path[level].bp_bh);
1261                 if (path[level].bp_index == 0)
1262                         nilfs_btree_promote_key(btree, path, level + 1,
1263                                 nilfs_btree_node_get_key(node, 0));
1264         } else {
1265                 node = nilfs_btree_get_root(btree);
1266                 nilfs_btree_node_delete(node, path[level].bp_index,
1267                                         keyp, ptrp,
1268                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1269         }
1270 }
1271 
1272 static void nilfs_btree_borrow_left(struct nilfs_bmap *btree,
1273                                     struct nilfs_btree_path *path,
1274                                     int level, __u64 *keyp, __u64 *ptrp)
1275 {
1276         struct nilfs_btree_node *node, *left;
1277         int nchildren, lnchildren, n, ncblk;
1278 
1279         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1280 
1281         node = nilfs_btree_get_nonroot_node(path, level);
1282         left = nilfs_btree_get_sib_node(path, level);
1283         nchildren = nilfs_btree_node_get_nchildren(node);
1284         lnchildren = nilfs_btree_node_get_nchildren(left);
1285         ncblk = nilfs_btree_nchildren_per_block(btree);
1286 
1287         n = (nchildren + lnchildren) / 2 - nchildren;
1288 
1289         nilfs_btree_node_move_right(left, node, n, ncblk, ncblk);
1290 
1291         if (!buffer_dirty(path[level].bp_bh))
1292                 mark_buffer_dirty(path[level].bp_bh);
1293         if (!buffer_dirty(path[level].bp_sib_bh))
1294                 mark_buffer_dirty(path[level].bp_sib_bh);
1295 
1296         nilfs_btree_promote_key(btree, path, level + 1,
1297                                 nilfs_btree_node_get_key(node, 0));
1298 
1299         brelse(path[level].bp_sib_bh);
1300         path[level].bp_sib_bh = NULL;
1301         path[level].bp_index += n;
1302 }
1303 
1304 static void nilfs_btree_borrow_right(struct nilfs_bmap *btree,
1305                                      struct nilfs_btree_path *path,
1306                                      int level, __u64 *keyp, __u64 *ptrp)
1307 {
1308         struct nilfs_btree_node *node, *right;
1309         int nchildren, rnchildren, n, ncblk;
1310 
1311         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1312 
1313         node = nilfs_btree_get_nonroot_node(path, level);
1314         right = nilfs_btree_get_sib_node(path, level);
1315         nchildren = nilfs_btree_node_get_nchildren(node);
1316         rnchildren = nilfs_btree_node_get_nchildren(right);
1317         ncblk = nilfs_btree_nchildren_per_block(btree);
1318 
1319         n = (nchildren + rnchildren) / 2 - nchildren;
1320 
1321         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1322 
1323         if (!buffer_dirty(path[level].bp_bh))
1324                 mark_buffer_dirty(path[level].bp_bh);
1325         if (!buffer_dirty(path[level].bp_sib_bh))
1326                 mark_buffer_dirty(path[level].bp_sib_bh);
1327 
1328         path[level + 1].bp_index++;
1329         nilfs_btree_promote_key(btree, path, level + 1,
1330                                 nilfs_btree_node_get_key(right, 0));
1331         path[level + 1].bp_index--;
1332 
1333         brelse(path[level].bp_sib_bh);
1334         path[level].bp_sib_bh = NULL;
1335 }
1336 
1337 static void nilfs_btree_concat_left(struct nilfs_bmap *btree,
1338                                     struct nilfs_btree_path *path,
1339                                     int level, __u64 *keyp, __u64 *ptrp)
1340 {
1341         struct nilfs_btree_node *node, *left;
1342         int n, ncblk;
1343 
1344         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1345 
1346         node = nilfs_btree_get_nonroot_node(path, level);
1347         left = nilfs_btree_get_sib_node(path, level);
1348         ncblk = nilfs_btree_nchildren_per_block(btree);
1349 
1350         n = nilfs_btree_node_get_nchildren(node);
1351 
1352         nilfs_btree_node_move_left(left, node, n, ncblk, ncblk);
1353 
1354         if (!buffer_dirty(path[level].bp_sib_bh))
1355                 mark_buffer_dirty(path[level].bp_sib_bh);
1356 
1357         nilfs_btnode_delete(path[level].bp_bh);
1358         path[level].bp_bh = path[level].bp_sib_bh;
1359         path[level].bp_sib_bh = NULL;
1360         path[level].bp_index += nilfs_btree_node_get_nchildren(left);
1361 }
1362 
1363 static void nilfs_btree_concat_right(struct nilfs_bmap *btree,
1364                                      struct nilfs_btree_path *path,
1365                                      int level, __u64 *keyp, __u64 *ptrp)
1366 {
1367         struct nilfs_btree_node *node, *right;
1368         int n, ncblk;
1369 
1370         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1371 
1372         node = nilfs_btree_get_nonroot_node(path, level);
1373         right = nilfs_btree_get_sib_node(path, level);
1374         ncblk = nilfs_btree_nchildren_per_block(btree);
1375 
1376         n = nilfs_btree_node_get_nchildren(right);
1377 
1378         nilfs_btree_node_move_left(node, right, n, ncblk, ncblk);
1379 
1380         if (!buffer_dirty(path[level].bp_bh))
1381                 mark_buffer_dirty(path[level].bp_bh);
1382 
1383         nilfs_btnode_delete(path[level].bp_sib_bh);
1384         path[level].bp_sib_bh = NULL;
1385         path[level + 1].bp_index++;
1386 }
1387 
1388 static void nilfs_btree_shrink(struct nilfs_bmap *btree,
1389                                struct nilfs_btree_path *path,
1390                                int level, __u64 *keyp, __u64 *ptrp)
1391 {
1392         struct nilfs_btree_node *root, *child;
1393         int n, ncblk;
1394 
1395         nilfs_btree_do_delete(btree, path, level, keyp, ptrp);
1396 
1397         root = nilfs_btree_get_root(btree);
1398         child = nilfs_btree_get_nonroot_node(path, level);
1399         ncblk = nilfs_btree_nchildren_per_block(btree);
1400 
1401         nilfs_btree_node_delete(root, 0, NULL, NULL,
1402                                 NILFS_BTREE_ROOT_NCHILDREN_MAX);
1403         nilfs_btree_node_set_level(root, level);
1404         n = nilfs_btree_node_get_nchildren(child);
1405         nilfs_btree_node_move_left(root, child, n,
1406                                    NILFS_BTREE_ROOT_NCHILDREN_MAX, ncblk);
1407 
1408         nilfs_btnode_delete(path[level].bp_bh);
1409         path[level].bp_bh = NULL;
1410 }
1411 
1412 static void nilfs_btree_nop(struct nilfs_bmap *btree,
1413                             struct nilfs_btree_path *path,
1414                             int level, __u64 *keyp, __u64 *ptrp)
1415 {
1416 }
1417 
1418 static int nilfs_btree_prepare_delete(struct nilfs_bmap *btree,
1419                                       struct nilfs_btree_path *path,
1420                                       int *levelp,
1421                                       struct nilfs_bmap_stats *stats,
1422                                       struct inode *dat)
1423 {
1424         struct buffer_head *bh;
1425         struct nilfs_btree_node *node, *parent, *sib;
1426         __u64 sibptr;
1427         int pindex, dindex, level, ncmin, ncmax, ncblk, ret;
1428 
1429         ret = 0;
1430         stats->bs_nblocks = 0;
1431         ncmin = NILFS_BTREE_NODE_NCHILDREN_MIN(nilfs_btree_node_size(btree));
1432         ncblk = nilfs_btree_nchildren_per_block(btree);
1433 
1434         for (level = NILFS_BTREE_LEVEL_NODE_MIN, dindex = path[level].bp_index;
1435              level < nilfs_btree_height(btree) - 1;
1436              level++) {
1437                 node = nilfs_btree_get_nonroot_node(path, level);
1438                 path[level].bp_oldreq.bpr_ptr =
1439                         nilfs_btree_node_get_ptr(node, dindex, ncblk);
1440                 ret = nilfs_bmap_prepare_end_ptr(btree,
1441                                                  &path[level].bp_oldreq, dat);
1442                 if (ret < 0)
1443                         goto err_out_child_node;
1444 
1445                 if (nilfs_btree_node_get_nchildren(node) > ncmin) {
1446                         path[level].bp_op = nilfs_btree_do_delete;
1447                         stats->bs_nblocks++;
1448                         goto out;
1449                 }
1450 
1451                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1452                 pindex = path[level + 1].bp_index;
1453                 dindex = pindex;
1454 
1455                 if (pindex > 0) {
1456                         /* left sibling */
1457                         sibptr = nilfs_btree_node_get_ptr(parent, pindex - 1,
1458                                                           ncmax);
1459                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1460                         if (ret < 0)
1461                                 goto err_out_curr_node;
1462                         sib = (struct nilfs_btree_node *)bh->b_data;
1463                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1464                                 path[level].bp_sib_bh = bh;
1465                                 path[level].bp_op = nilfs_btree_borrow_left;
1466                                 stats->bs_nblocks++;
1467                                 goto out;
1468                         } else {
1469                                 path[level].bp_sib_bh = bh;
1470                                 path[level].bp_op = nilfs_btree_concat_left;
1471                                 stats->bs_nblocks++;
1472                                 /* continue; */
1473                         }
1474                 } else if (pindex <
1475                            nilfs_btree_node_get_nchildren(parent) - 1) {
1476                         /* right sibling */
1477                         sibptr = nilfs_btree_node_get_ptr(parent, pindex + 1,
1478                                                           ncmax);
1479                         ret = nilfs_btree_get_block(btree, sibptr, &bh);
1480                         if (ret < 0)
1481                                 goto err_out_curr_node;
1482                         sib = (struct nilfs_btree_node *)bh->b_data;
1483                         if (nilfs_btree_node_get_nchildren(sib) > ncmin) {
1484                                 path[level].bp_sib_bh = bh;
1485                                 path[level].bp_op = nilfs_btree_borrow_right;
1486                                 stats->bs_nblocks++;
1487                                 goto out;
1488                         } else {
1489                                 path[level].bp_sib_bh = bh;
1490                                 path[level].bp_op = nilfs_btree_concat_right;
1491                                 stats->bs_nblocks++;
1492                                 /*
1493                                  * When merging right sibling node
1494                                  * into the current node, pointer to
1495                                  * the right sibling node must be
1496                                  * terminated instead.  The adjustment
1497                                  * below is required for that.
1498                                  */
1499                                 dindex = pindex + 1;
1500                                 /* continue; */
1501                         }
1502                 } else {
1503                         /* no siblings */
1504                         /* the only child of the root node */
1505                         WARN_ON(level != nilfs_btree_height(btree) - 2);
1506                         if (nilfs_btree_node_get_nchildren(node) - 1 <=
1507                             NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1508                                 path[level].bp_op = nilfs_btree_shrink;
1509                                 stats->bs_nblocks += 2;
1510                                 level++;
1511                                 path[level].bp_op = nilfs_btree_nop;
1512                                 goto shrink_root_child;
1513                         } else {
1514                                 path[level].bp_op = nilfs_btree_do_delete;
1515                                 stats->bs_nblocks++;
1516                                 goto out;
1517                         }
1518                 }
1519         }
1520 
1521         /* child of the root node is deleted */
1522         path[level].bp_op = nilfs_btree_do_delete;
1523         stats->bs_nblocks++;
1524 
1525 shrink_root_child:
1526         node = nilfs_btree_get_root(btree);
1527         path[level].bp_oldreq.bpr_ptr =
1528                 nilfs_btree_node_get_ptr(node, dindex,
1529                                          NILFS_BTREE_ROOT_NCHILDREN_MAX);
1530 
1531         ret = nilfs_bmap_prepare_end_ptr(btree, &path[level].bp_oldreq, dat);
1532         if (ret < 0)
1533                 goto err_out_child_node;
1534 
1535         /* success */
1536  out:
1537         *levelp = level;
1538         return ret;
1539 
1540         /* error */
1541  err_out_curr_node:
1542         nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1543  err_out_child_node:
1544         for (level--; level >= NILFS_BTREE_LEVEL_NODE_MIN; level--) {
1545                 brelse(path[level].bp_sib_bh);
1546                 nilfs_bmap_abort_end_ptr(btree, &path[level].bp_oldreq, dat);
1547         }
1548         *levelp = level;
1549         stats->bs_nblocks = 0;
1550         return ret;
1551 }
1552 
1553 static void nilfs_btree_commit_delete(struct nilfs_bmap *btree,
1554                                       struct nilfs_btree_path *path,
1555                                       int maxlevel, struct inode *dat)
1556 {
1557         int level;
1558 
1559         for (level = NILFS_BTREE_LEVEL_NODE_MIN; level <= maxlevel; level++) {
1560                 nilfs_bmap_commit_end_ptr(btree, &path[level].bp_oldreq, dat);
1561                 path[level].bp_op(btree, path, level, NULL, NULL);
1562         }
1563 
1564         if (!nilfs_bmap_dirty(btree))
1565                 nilfs_bmap_set_dirty(btree);
1566 }
1567 
1568 static int nilfs_btree_delete(struct nilfs_bmap *btree, __u64 key)
1569 
1570 {
1571         struct nilfs_btree_path *path;
1572         struct nilfs_bmap_stats stats;
1573         struct inode *dat;
1574         int level, ret;
1575 
1576         path = nilfs_btree_alloc_path();
1577         if (path == NULL)
1578                 return -ENOMEM;
1579 
1580         ret = nilfs_btree_do_lookup(btree, path, key, NULL,
1581                                     NILFS_BTREE_LEVEL_NODE_MIN, 0);
1582         if (ret < 0)
1583                 goto out;
1584 
1585 
1586         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1587 
1588         ret = nilfs_btree_prepare_delete(btree, path, &level, &stats, dat);
1589         if (ret < 0)
1590                 goto out;
1591         nilfs_btree_commit_delete(btree, path, level, dat);
1592         nilfs_inode_sub_blocks(btree->b_inode, stats.bs_nblocks);
1593 
1594 out:
1595         nilfs_btree_free_path(path);
1596         return ret;
1597 }
1598 
1599 static int nilfs_btree_seek_key(const struct nilfs_bmap *btree, __u64 start,
1600                                 __u64 *keyp)
1601 {
1602         struct nilfs_btree_path *path;
1603         const int minlevel = NILFS_BTREE_LEVEL_NODE_MIN;
1604         int ret;
1605 
1606         path = nilfs_btree_alloc_path();
1607         if (!path)
1608                 return -ENOMEM;
1609 
1610         ret = nilfs_btree_do_lookup(btree, path, start, NULL, minlevel, 0);
1611         if (!ret)
1612                 *keyp = start;
1613         else if (ret == -ENOENT)
1614                 ret = nilfs_btree_get_next_key(btree, path, minlevel, keyp);
1615 
1616         nilfs_btree_free_path(path);
1617         return ret;
1618 }
1619 
1620 static int nilfs_btree_last_key(const struct nilfs_bmap *btree, __u64 *keyp)
1621 {
1622         struct nilfs_btree_path *path;
1623         int ret;
1624 
1625         path = nilfs_btree_alloc_path();
1626         if (path == NULL)
1627                 return -ENOMEM;
1628 
1629         ret = nilfs_btree_do_lookup_last(btree, path, keyp, NULL);
1630 
1631         nilfs_btree_free_path(path);
1632 
1633         return ret;
1634 }
1635 
1636 static int nilfs_btree_check_delete(struct nilfs_bmap *btree, __u64 key)
1637 {
1638         struct buffer_head *bh;
1639         struct nilfs_btree_node *root, *node;
1640         __u64 maxkey, nextmaxkey;
1641         __u64 ptr;
1642         int nchildren, ret;
1643 
1644         root = nilfs_btree_get_root(btree);
1645         switch (nilfs_btree_height(btree)) {
1646         case 2:
1647                 bh = NULL;
1648                 node = root;
1649                 break;
1650         case 3:
1651                 nchildren = nilfs_btree_node_get_nchildren(root);
1652                 if (nchildren > 1)
1653                         return 0;
1654                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1655                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1656                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1657                 if (ret < 0)
1658                         return ret;
1659                 node = (struct nilfs_btree_node *)bh->b_data;
1660                 break;
1661         default:
1662                 return 0;
1663         }
1664 
1665         nchildren = nilfs_btree_node_get_nchildren(node);
1666         maxkey = nilfs_btree_node_get_key(node, nchildren - 1);
1667         nextmaxkey = (nchildren > 1) ?
1668                 nilfs_btree_node_get_key(node, nchildren - 2) : 0;
1669         if (bh != NULL)
1670                 brelse(bh);
1671 
1672         return (maxkey == key) && (nextmaxkey < NILFS_BMAP_LARGE_LOW);
1673 }
1674 
1675 static int nilfs_btree_gather_data(struct nilfs_bmap *btree,
1676                                    __u64 *keys, __u64 *ptrs, int nitems)
1677 {
1678         struct buffer_head *bh;
1679         struct nilfs_btree_node *node, *root;
1680         __le64 *dkeys;
1681         __le64 *dptrs;
1682         __u64 ptr;
1683         int nchildren, ncmax, i, ret;
1684 
1685         root = nilfs_btree_get_root(btree);
1686         switch (nilfs_btree_height(btree)) {
1687         case 2:
1688                 bh = NULL;
1689                 node = root;
1690                 ncmax = NILFS_BTREE_ROOT_NCHILDREN_MAX;
1691                 break;
1692         case 3:
1693                 nchildren = nilfs_btree_node_get_nchildren(root);
1694                 WARN_ON(nchildren > 1);
1695                 ptr = nilfs_btree_node_get_ptr(root, nchildren - 1,
1696                                                NILFS_BTREE_ROOT_NCHILDREN_MAX);
1697                 ret = nilfs_btree_get_block(btree, ptr, &bh);
1698                 if (ret < 0)
1699                         return ret;
1700                 node = (struct nilfs_btree_node *)bh->b_data;
1701                 ncmax = nilfs_btree_nchildren_per_block(btree);
1702                 break;
1703         default:
1704                 node = NULL;
1705                 return -EINVAL;
1706         }
1707 
1708         nchildren = nilfs_btree_node_get_nchildren(node);
1709         if (nchildren < nitems)
1710                 nitems = nchildren;
1711         dkeys = nilfs_btree_node_dkeys(node);
1712         dptrs = nilfs_btree_node_dptrs(node, ncmax);
1713         for (i = 0; i < nitems; i++) {
1714                 keys[i] = le64_to_cpu(dkeys[i]);
1715                 ptrs[i] = le64_to_cpu(dptrs[i]);
1716         }
1717 
1718         if (bh != NULL)
1719                 brelse(bh);
1720 
1721         return nitems;
1722 }
1723 
1724 static int
1725 nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
1726                                        union nilfs_bmap_ptr_req *dreq,
1727                                        union nilfs_bmap_ptr_req *nreq,
1728                                        struct buffer_head **bhp,
1729                                        struct nilfs_bmap_stats *stats)
1730 {
1731         struct buffer_head *bh;
1732         struct inode *dat = NULL;
1733         int ret;
1734 
1735         stats->bs_nblocks = 0;
1736 
1737         /* for data */
1738         /* cannot find near ptr */
1739         if (NILFS_BMAP_USE_VBN(btree)) {
1740                 dreq->bpr_ptr = nilfs_btree_find_target_v(btree, NULL, key);
1741                 dat = nilfs_bmap_get_dat(btree);
1742         }
1743 
1744         ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
1745         if (ret < 0)
1746                 return ret;
1747 
1748         *bhp = NULL;
1749         stats->bs_nblocks++;
1750         if (nreq != NULL) {
1751                 nreq->bpr_ptr = dreq->bpr_ptr + 1;
1752                 ret = nilfs_bmap_prepare_alloc_ptr(btree, nreq, dat);
1753                 if (ret < 0)
1754                         goto err_out_dreq;
1755 
1756                 ret = nilfs_btree_get_new_block(btree, nreq->bpr_ptr, &bh);
1757                 if (ret < 0)
1758                         goto err_out_nreq;
1759 
1760                 *bhp = bh;
1761                 stats->bs_nblocks++;
1762         }
1763 
1764         /* success */
1765         return 0;
1766 
1767         /* error */
1768  err_out_nreq:
1769         nilfs_bmap_abort_alloc_ptr(btree, nreq, dat);
1770  err_out_dreq:
1771         nilfs_bmap_abort_alloc_ptr(btree, dreq, dat);
1772         stats->bs_nblocks = 0;
1773         return ret;
1774 
1775 }
1776 
1777 static void
1778 nilfs_btree_commit_convert_and_insert(struct nilfs_bmap *btree,
1779                                       __u64 key, __u64 ptr,
1780                                       const __u64 *keys, const __u64 *ptrs,
1781                                       int n,
1782                                       union nilfs_bmap_ptr_req *dreq,
1783                                       union nilfs_bmap_ptr_req *nreq,
1784                                       struct buffer_head *bh)
1785 {
1786         struct nilfs_btree_node *node;
1787         struct inode *dat;
1788         __u64 tmpptr;
1789         int ncblk;
1790 
1791         /* free resources */
1792         if (btree->b_ops->bop_clear != NULL)
1793                 btree->b_ops->bop_clear(btree);
1794 
1795         /* ptr must be a pointer to a buffer head. */
1796         set_buffer_nilfs_volatile((struct buffer_head *)((unsigned long)ptr));
1797 
1798         /* convert and insert */
1799         dat = NILFS_BMAP_USE_VBN(btree) ? nilfs_bmap_get_dat(btree) : NULL;
1800         __nilfs_btree_init(btree);
1801         if (nreq != NULL) {
1802                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1803                 nilfs_bmap_commit_alloc_ptr(btree, nreq, dat);
1804 
1805                 /* create child node at level 1 */
1806                 node = (struct nilfs_btree_node *)bh->b_data;
1807                 ncblk = nilfs_btree_nchildren_per_block(btree);
1808                 nilfs_btree_node_init(node, 0, 1, n, ncblk, keys, ptrs);
1809                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr, ncblk);
1810                 if (!buffer_dirty(bh))
1811                         mark_buffer_dirty(bh);
1812                 if (!nilfs_bmap_dirty(btree))
1813                         nilfs_bmap_set_dirty(btree);
1814 
1815                 brelse(bh);
1816 
1817                 /* create root node at level 2 */
1818                 node = nilfs_btree_get_root(btree);
1819                 tmpptr = nreq->bpr_ptr;
1820                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 2, 1,
1821                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1822                                       &keys[0], &tmpptr);
1823         } else {
1824                 nilfs_bmap_commit_alloc_ptr(btree, dreq, dat);
1825 
1826                 /* create root node at level 1 */
1827                 node = nilfs_btree_get_root(btree);
1828                 nilfs_btree_node_init(node, NILFS_BTREE_NODE_ROOT, 1, n,
1829                                       NILFS_BTREE_ROOT_NCHILDREN_MAX,
1830                                       keys, ptrs);
1831                 nilfs_btree_node_insert(node, n, key, dreq->bpr_ptr,
1832                                         NILFS_BTREE_ROOT_NCHILDREN_MAX);
1833                 if (!nilfs_bmap_dirty(btree))
1834                         nilfs_bmap_set_dirty(btree);
1835         }
1836 
1837         if (NILFS_BMAP_USE_VBN(btree))
1838                 nilfs_bmap_set_target_v(btree, key, dreq->bpr_ptr);
1839 }
1840 
1841 /**
1842  * nilfs_btree_convert_and_insert -
1843  * @bmap:
1844  * @key:
1845  * @ptr:
1846  * @keys:
1847  * @ptrs:
1848  * @n:
1849  */
1850 int nilfs_btree_convert_and_insert(struct nilfs_bmap *btree,
1851                                    __u64 key, __u64 ptr,
1852                                    const __u64 *keys, const __u64 *ptrs, int n)
1853 {
1854         struct buffer_head *bh = NULL;
1855         union nilfs_bmap_ptr_req dreq, nreq, *di, *ni;
1856         struct nilfs_bmap_stats stats;
1857         int ret;
1858 
1859         if (n + 1 <= NILFS_BTREE_ROOT_NCHILDREN_MAX) {
1860                 di = &dreq;
1861                 ni = NULL;
1862         } else if ((n + 1) <= NILFS_BTREE_NODE_NCHILDREN_MAX(
1863                            1 << btree->b_inode->i_blkbits)) {
1864                 di = &dreq;
1865                 ni = &nreq;
1866         } else {
1867                 di = NULL;
1868                 ni = NULL;
1869                 BUG();
1870         }
1871 
1872         ret = nilfs_btree_prepare_convert_and_insert(btree, key, di, ni, &bh,
1873                                                      &stats);
1874         if (ret < 0)
1875                 return ret;
1876         nilfs_btree_commit_convert_and_insert(btree, key, ptr, keys, ptrs, n,
1877                                               di, ni, bh);
1878         nilfs_inode_add_blocks(btree->b_inode, stats.bs_nblocks);
1879         return 0;
1880 }
1881 
1882 static int nilfs_btree_propagate_p(struct nilfs_bmap *btree,
1883                                    struct nilfs_btree_path *path,
1884                                    int level,
1885                                    struct buffer_head *bh)
1886 {
1887         while ((++level < nilfs_btree_height(btree) - 1) &&
1888                !buffer_dirty(path[level].bp_bh))
1889                 mark_buffer_dirty(path[level].bp_bh);
1890 
1891         return 0;
1892 }
1893 
1894 static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
1895                                         struct nilfs_btree_path *path,
1896                                         int level, struct inode *dat)
1897 {
1898         struct nilfs_btree_node *parent;
1899         int ncmax, ret;
1900 
1901         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1902         path[level].bp_oldreq.bpr_ptr =
1903                 nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
1904                                          ncmax);
1905         path[level].bp_newreq.bpr_ptr = path[level].bp_oldreq.bpr_ptr + 1;
1906         ret = nilfs_dat_prepare_update(dat, &path[level].bp_oldreq.bpr_req,
1907                                        &path[level].bp_newreq.bpr_req);
1908         if (ret < 0)
1909                 return ret;
1910 
1911         if (buffer_nilfs_node(path[level].bp_bh)) {
1912                 path[level].bp_ctxt.oldkey = path[level].bp_oldreq.bpr_ptr;
1913                 path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
1914                 path[level].bp_ctxt.bh = path[level].bp_bh;
1915                 ret = nilfs_btnode_prepare_change_key(
1916                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1917                         &path[level].bp_ctxt);
1918                 if (ret < 0) {
1919                         nilfs_dat_abort_update(dat,
1920                                                &path[level].bp_oldreq.bpr_req,
1921                                                &path[level].bp_newreq.bpr_req);
1922                         return ret;
1923                 }
1924         }
1925 
1926         return 0;
1927 }
1928 
1929 static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
1930                                         struct nilfs_btree_path *path,
1931                                         int level, struct inode *dat)
1932 {
1933         struct nilfs_btree_node *parent;
1934         int ncmax;
1935 
1936         nilfs_dat_commit_update(dat, &path[level].bp_oldreq.bpr_req,
1937                                 &path[level].bp_newreq.bpr_req,
1938                                 btree->b_ptr_type == NILFS_BMAP_PTR_VS);
1939 
1940         if (buffer_nilfs_node(path[level].bp_bh)) {
1941                 nilfs_btnode_commit_change_key(
1942                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1943                         &path[level].bp_ctxt);
1944                 path[level].bp_bh = path[level].bp_ctxt.bh;
1945         }
1946         set_buffer_nilfs_volatile(path[level].bp_bh);
1947 
1948         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
1949         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index,
1950                                  path[level].bp_newreq.bpr_ptr, ncmax);
1951 }
1952 
1953 static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
1954                                        struct nilfs_btree_path *path,
1955                                        int level, struct inode *dat)
1956 {
1957         nilfs_dat_abort_update(dat, &path[level].bp_oldreq.bpr_req,
1958                                &path[level].bp_newreq.bpr_req);
1959         if (buffer_nilfs_node(path[level].bp_bh))
1960                 nilfs_btnode_abort_change_key(
1961                         &NILFS_BMAP_I(btree)->i_btnode_cache,
1962                         &path[level].bp_ctxt);
1963 }
1964 
1965 static int nilfs_btree_prepare_propagate_v(struct nilfs_bmap *btree,
1966                                            struct nilfs_btree_path *path,
1967                                            int minlevel, int *maxlevelp,
1968                                            struct inode *dat)
1969 {
1970         int level, ret;
1971 
1972         level = minlevel;
1973         if (!buffer_nilfs_volatile(path[level].bp_bh)) {
1974                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1975                 if (ret < 0)
1976                         return ret;
1977         }
1978         while ((++level < nilfs_btree_height(btree) - 1) &&
1979                !buffer_dirty(path[level].bp_bh)) {
1980 
1981                 WARN_ON(buffer_nilfs_volatile(path[level].bp_bh));
1982                 ret = nilfs_btree_prepare_update_v(btree, path, level, dat);
1983                 if (ret < 0)
1984                         goto out;
1985         }
1986 
1987         /* success */
1988         *maxlevelp = level - 1;
1989         return 0;
1990 
1991         /* error */
1992  out:
1993         while (--level > minlevel)
1994                 nilfs_btree_abort_update_v(btree, path, level, dat);
1995         if (!buffer_nilfs_volatile(path[level].bp_bh))
1996                 nilfs_btree_abort_update_v(btree, path, level, dat);
1997         return ret;
1998 }
1999 
2000 static void nilfs_btree_commit_propagate_v(struct nilfs_bmap *btree,
2001                                            struct nilfs_btree_path *path,
2002                                            int minlevel, int maxlevel,
2003                                            struct buffer_head *bh,
2004                                            struct inode *dat)
2005 {
2006         int level;
2007 
2008         if (!buffer_nilfs_volatile(path[minlevel].bp_bh))
2009                 nilfs_btree_commit_update_v(btree, path, minlevel, dat);
2010 
2011         for (level = minlevel + 1; level <= maxlevel; level++)
2012                 nilfs_btree_commit_update_v(btree, path, level, dat);
2013 }
2014 
2015 static int nilfs_btree_propagate_v(struct nilfs_bmap *btree,
2016                                    struct nilfs_btree_path *path,
2017                                    int level, struct buffer_head *bh)
2018 {
2019         int maxlevel = 0, ret;
2020         struct nilfs_btree_node *parent;
2021         struct inode *dat = nilfs_bmap_get_dat(btree);
2022         __u64 ptr;
2023         int ncmax;
2024 
2025         get_bh(bh);
2026         path[level].bp_bh = bh;
2027         ret = nilfs_btree_prepare_propagate_v(btree, path, level, &maxlevel,
2028                                               dat);
2029         if (ret < 0)
2030                 goto out;
2031 
2032         if (buffer_nilfs_volatile(path[level].bp_bh)) {
2033                 parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2034                 ptr = nilfs_btree_node_get_ptr(parent,
2035                                                path[level + 1].bp_index,
2036                                                ncmax);
2037                 ret = nilfs_dat_mark_dirty(dat, ptr);
2038                 if (ret < 0)
2039                         goto out;
2040         }
2041 
2042         nilfs_btree_commit_propagate_v(btree, path, level, maxlevel, bh, dat);
2043 
2044  out:
2045         brelse(path[level].bp_bh);
2046         path[level].bp_bh = NULL;
2047         return ret;
2048 }
2049 
2050 static int nilfs_btree_propagate(struct nilfs_bmap *btree,
2051                                  struct buffer_head *bh)
2052 {
2053         struct nilfs_btree_path *path;
2054         struct nilfs_btree_node *node;
2055         __u64 key;
2056         int level, ret;
2057 
2058         WARN_ON(!buffer_dirty(bh));
2059 
2060         path = nilfs_btree_alloc_path();
2061         if (path == NULL)
2062                 return -ENOMEM;
2063 
2064         if (buffer_nilfs_node(bh)) {
2065                 node = (struct nilfs_btree_node *)bh->b_data;
2066                 key = nilfs_btree_node_get_key(node, 0);
2067                 level = nilfs_btree_node_get_level(node);
2068         } else {
2069                 key = nilfs_bmap_data_get_key(btree, bh);
2070                 level = NILFS_BTREE_LEVEL_DATA;
2071         }
2072 
2073         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2074         if (ret < 0) {
2075                 if (unlikely(ret == -ENOENT))
2076                         printk(KERN_CRIT "%s: key = %llu, level == %d\n",
2077                                __func__, (unsigned long long)key, level);
2078                 goto out;
2079         }
2080 
2081         ret = NILFS_BMAP_USE_VBN(btree) ?
2082                 nilfs_btree_propagate_v(btree, path, level, bh) :
2083                 nilfs_btree_propagate_p(btree, path, level, bh);
2084 
2085  out:
2086         nilfs_btree_free_path(path);
2087 
2088         return ret;
2089 }
2090 
2091 static int nilfs_btree_propagate_gc(struct nilfs_bmap *btree,
2092                                     struct buffer_head *bh)
2093 {
2094         return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(btree), bh->b_blocknr);
2095 }
2096 
2097 static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
2098                                          struct list_head *lists,
2099                                          struct buffer_head *bh)
2100 {
2101         struct list_head *head;
2102         struct buffer_head *cbh;
2103         struct nilfs_btree_node *node, *cnode;
2104         __u64 key, ckey;
2105         int level;
2106 
2107         get_bh(bh);
2108         node = (struct nilfs_btree_node *)bh->b_data;
2109         key = nilfs_btree_node_get_key(node, 0);
2110         level = nilfs_btree_node_get_level(node);
2111         if (level < NILFS_BTREE_LEVEL_NODE_MIN ||
2112             level >= NILFS_BTREE_LEVEL_MAX) {
2113                 dump_stack();
2114                 printk(KERN_WARNING
2115                        "%s: invalid btree level: %d (key=%llu, ino=%lu, "
2116                        "blocknr=%llu)\n",
2117                        __func__, level, (unsigned long long)key,
2118                        NILFS_BMAP_I(btree)->vfs_inode.i_ino,
2119                        (unsigned long long)bh->b_blocknr);
2120                 return;
2121         }
2122 
2123         list_for_each(head, &lists[level]) {
2124                 cbh = list_entry(head, struct buffer_head, b_assoc_buffers);
2125                 cnode = (struct nilfs_btree_node *)cbh->b_data;
2126                 ckey = nilfs_btree_node_get_key(cnode, 0);
2127                 if (key < ckey)
2128                         break;
2129         }
2130         list_add_tail(&bh->b_assoc_buffers, head);
2131 }
2132 
2133 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
2134                                              struct list_head *listp)
2135 {
2136         struct address_space *btcache = &NILFS_BMAP_I(btree)->i_btnode_cache;
2137         struct list_head lists[NILFS_BTREE_LEVEL_MAX];
2138         struct pagevec pvec;
2139         struct buffer_head *bh, *head;
2140         pgoff_t index = 0;
2141         int level, i;
2142 
2143         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2144              level < NILFS_BTREE_LEVEL_MAX;
2145              level++)
2146                 INIT_LIST_HEAD(&lists[level]);
2147 
2148         pagevec_init(&pvec, 0);
2149 
2150         while (pagevec_lookup_tag(&pvec, btcache, &index, PAGECACHE_TAG_DIRTY,
2151                                   PAGEVEC_SIZE)) {
2152                 for (i = 0; i < pagevec_count(&pvec); i++) {
2153                         bh = head = page_buffers(pvec.pages[i]);
2154                         do {
2155                                 if (buffer_dirty(bh))
2156                                         nilfs_btree_add_dirty_buffer(btree,
2157                                                                      lists, bh);
2158                         } while ((bh = bh->b_this_page) != head);
2159                 }
2160                 pagevec_release(&pvec);
2161                 cond_resched();
2162         }
2163 
2164         for (level = NILFS_BTREE_LEVEL_NODE_MIN;
2165              level < NILFS_BTREE_LEVEL_MAX;
2166              level++)
2167                 list_splice_tail(&lists[level], listp);
2168 }
2169 
2170 static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
2171                                 struct nilfs_btree_path *path,
2172                                 int level,
2173                                 struct buffer_head **bh,
2174                                 sector_t blocknr,
2175                                 union nilfs_binfo *binfo)
2176 {
2177         struct nilfs_btree_node *parent;
2178         __u64 key;
2179         __u64 ptr;
2180         int ncmax, ret;
2181 
2182         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2183         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2184                                        ncmax);
2185         if (buffer_nilfs_node(*bh)) {
2186                 path[level].bp_ctxt.oldkey = ptr;
2187                 path[level].bp_ctxt.newkey = blocknr;
2188                 path[level].bp_ctxt.bh = *bh;
2189                 ret = nilfs_btnode_prepare_change_key(
2190                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2191                         &path[level].bp_ctxt);
2192                 if (ret < 0)
2193                         return ret;
2194                 nilfs_btnode_commit_change_key(
2195                         &NILFS_BMAP_I(btree)->i_btnode_cache,
2196                         &path[level].bp_ctxt);
2197                 *bh = path[level].bp_ctxt.bh;
2198         }
2199 
2200         nilfs_btree_node_set_ptr(parent, path[level + 1].bp_index, blocknr,
2201                                  ncmax);
2202 
2203         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2204         /* on-disk format */
2205         binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
2206         binfo->bi_dat.bi_level = level;
2207 
2208         return 0;
2209 }
2210 
2211 static int nilfs_btree_assign_v(struct nilfs_bmap *btree,
2212                                 struct nilfs_btree_path *path,
2213                                 int level,
2214                                 struct buffer_head **bh,
2215                                 sector_t blocknr,
2216                                 union nilfs_binfo *binfo)
2217 {
2218         struct nilfs_btree_node *parent;
2219         struct inode *dat = nilfs_bmap_get_dat(btree);
2220         __u64 key;
2221         __u64 ptr;
2222         union nilfs_bmap_ptr_req req;
2223         int ncmax, ret;
2224 
2225         parent = nilfs_btree_get_node(btree, path, level + 1, &ncmax);
2226         ptr = nilfs_btree_node_get_ptr(parent, path[level + 1].bp_index,
2227                                        ncmax);
2228         req.bpr_ptr = ptr;
2229         ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
2230         if (ret < 0)
2231                 return ret;
2232         nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
2233 
2234         key = nilfs_btree_node_get_key(parent, path[level + 1].bp_index);
2235         /* on-disk format */
2236         binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
2237         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2238 
2239         return 0;
2240 }
2241 
2242 static int nilfs_btree_assign(struct nilfs_bmap *btree,
2243                               struct buffer_head **bh,
2244                               sector_t blocknr,
2245                               union nilfs_binfo *binfo)
2246 {
2247         struct nilfs_btree_path *path;
2248         struct nilfs_btree_node *node;
2249         __u64 key;
2250         int level, ret;
2251 
2252         path = nilfs_btree_alloc_path();
2253         if (path == NULL)
2254                 return -ENOMEM;
2255 
2256         if (buffer_nilfs_node(*bh)) {
2257                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2258                 key = nilfs_btree_node_get_key(node, 0);
2259                 level = nilfs_btree_node_get_level(node);
2260         } else {
2261                 key = nilfs_bmap_data_get_key(btree, *bh);
2262                 level = NILFS_BTREE_LEVEL_DATA;
2263         }
2264 
2265         ret = nilfs_btree_do_lookup(btree, path, key, NULL, level + 1, 0);
2266         if (ret < 0) {
2267                 WARN_ON(ret == -ENOENT);
2268                 goto out;
2269         }
2270 
2271         ret = NILFS_BMAP_USE_VBN(btree) ?
2272                 nilfs_btree_assign_v(btree, path, level, bh, blocknr, binfo) :
2273                 nilfs_btree_assign_p(btree, path, level, bh, blocknr, binfo);
2274 
2275  out:
2276         nilfs_btree_free_path(path);
2277 
2278         return ret;
2279 }
2280 
2281 static int nilfs_btree_assign_gc(struct nilfs_bmap *btree,
2282                                  struct buffer_head **bh,
2283                                  sector_t blocknr,
2284                                  union nilfs_binfo *binfo)
2285 {
2286         struct nilfs_btree_node *node;
2287         __u64 key;
2288         int ret;
2289 
2290         ret = nilfs_dat_move(nilfs_bmap_get_dat(btree), (*bh)->b_blocknr,
2291                              blocknr);
2292         if (ret < 0)
2293                 return ret;
2294 
2295         if (buffer_nilfs_node(*bh)) {
2296                 node = (struct nilfs_btree_node *)(*bh)->b_data;
2297                 key = nilfs_btree_node_get_key(node, 0);
2298         } else
2299                 key = nilfs_bmap_data_get_key(btree, *bh);
2300 
2301         /* on-disk format */
2302         binfo->bi_v.bi_vblocknr = cpu_to_le64((*bh)->b_blocknr);
2303         binfo->bi_v.bi_blkoff = cpu_to_le64(key);
2304 
2305         return 0;
2306 }
2307 
2308 static int nilfs_btree_mark(struct nilfs_bmap *btree, __u64 key, int level)
2309 {
2310         struct buffer_head *bh;
2311         struct nilfs_btree_path *path;
2312         __u64 ptr;
2313         int ret;
2314 
2315         path = nilfs_btree_alloc_path();
2316         if (path == NULL)
2317                 return -ENOMEM;
2318 
2319         ret = nilfs_btree_do_lookup(btree, path, key, &ptr, level + 1, 0);
2320         if (ret < 0) {
2321                 WARN_ON(ret == -ENOENT);
2322                 goto out;
2323         }
2324         ret = nilfs_btree_get_block(btree, ptr, &bh);
2325         if (ret < 0) {
2326                 WARN_ON(ret == -ENOENT);
2327                 goto out;
2328         }
2329 
2330         if (!buffer_dirty(bh))
2331                 mark_buffer_dirty(bh);
2332         brelse(bh);
2333         if (!nilfs_bmap_dirty(btree))
2334                 nilfs_bmap_set_dirty(btree);
2335 
2336  out:
2337         nilfs_btree_free_path(path);
2338         return ret;
2339 }
2340 
2341 static const struct nilfs_bmap_operations nilfs_btree_ops = {
2342         .bop_lookup             =       nilfs_btree_lookup,
2343         .bop_lookup_contig      =       nilfs_btree_lookup_contig,
2344         .bop_insert             =       nilfs_btree_insert,
2345         .bop_delete             =       nilfs_btree_delete,
2346         .bop_clear              =       NULL,
2347 
2348         .bop_propagate          =       nilfs_btree_propagate,
2349 
2350         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2351 
2352         .bop_assign             =       nilfs_btree_assign,
2353         .bop_mark               =       nilfs_btree_mark,
2354 
2355         .bop_seek_key           =       nilfs_btree_seek_key,
2356         .bop_last_key           =       nilfs_btree_last_key,
2357 
2358         .bop_check_insert       =       NULL,
2359         .bop_check_delete       =       nilfs_btree_check_delete,
2360         .bop_gather_data        =       nilfs_btree_gather_data,
2361 };
2362 
2363 static const struct nilfs_bmap_operations nilfs_btree_ops_gc = {
2364         .bop_lookup             =       NULL,
2365         .bop_lookup_contig      =       NULL,
2366         .bop_insert             =       NULL,
2367         .bop_delete             =       NULL,
2368         .bop_clear              =       NULL,
2369 
2370         .bop_propagate          =       nilfs_btree_propagate_gc,
2371 
2372         .bop_lookup_dirty_buffers =     nilfs_btree_lookup_dirty_buffers,
2373 
2374         .bop_assign             =       nilfs_btree_assign_gc,
2375         .bop_mark               =       NULL,
2376 
2377         .bop_seek_key           =       NULL,
2378         .bop_last_key           =       NULL,
2379 
2380         .bop_check_insert       =       NULL,
2381         .bop_check_delete       =       NULL,
2382         .bop_gather_data        =       NULL,
2383 };
2384 
2385 static void __nilfs_btree_init(struct nilfs_bmap *bmap)
2386 {
2387         bmap->b_ops = &nilfs_btree_ops;
2388         bmap->b_nchildren_per_block =
2389                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2390 }
2391 
2392 int nilfs_btree_init(struct nilfs_bmap *bmap)
2393 {
2394         int ret = 0;
2395 
2396         __nilfs_btree_init(bmap);
2397 
2398         if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap),
2399                                     bmap->b_inode->i_ino))
2400                 ret = -EIO;
2401         return ret;
2402 }
2403 
2404 void nilfs_btree_init_gc(struct nilfs_bmap *bmap)
2405 {
2406         bmap->b_ops = &nilfs_btree_ops_gc;
2407         bmap->b_nchildren_per_block =
2408                 NILFS_BTREE_NODE_NCHILDREN_MAX(nilfs_btree_node_size(bmap));
2409 }
2410 

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