xref: /openbmc/linux/fs/reiserfs/stree.c (revision 55fd7e02)
1 /*
2  *  Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3  */
4 
5 /*
6  *  Written by Anatoly P. Pinchuk pap@namesys.botik.ru
7  *  Programm System Institute
8  *  Pereslavl-Zalessky Russia
9  */
10 
11 #include <linux/time.h>
12 #include <linux/string.h>
13 #include <linux/pagemap.h>
14 #include <linux/bio.h>
15 #include "reiserfs.h"
16 #include <linux/buffer_head.h>
17 #include <linux/quotaops.h>
18 
19 /* Does the buffer contain a disk block which is in the tree. */
20 inline int B_IS_IN_TREE(const struct buffer_head *bh)
21 {
22 
23 	RFALSE(B_LEVEL(bh) > MAX_HEIGHT,
24 	       "PAP-1010: block (%b) has too big level (%z)", bh, bh);
25 
26 	return (B_LEVEL(bh) != FREE_LEVEL);
27 }
28 
29 /* to get item head in le form */
30 inline void copy_item_head(struct item_head *to,
31 			   const struct item_head *from)
32 {
33 	memcpy(to, from, IH_SIZE);
34 }
35 
36 /*
37  * k1 is pointer to on-disk structure which is stored in little-endian
38  * form. k2 is pointer to cpu variable. For key of items of the same
39  * object this returns 0.
40  * Returns: -1 if key1 < key2
41  * 0 if key1 == key2
42  * 1 if key1 > key2
43  */
44 inline int comp_short_keys(const struct reiserfs_key *le_key,
45 			   const struct cpu_key *cpu_key)
46 {
47 	__u32 n;
48 	n = le32_to_cpu(le_key->k_dir_id);
49 	if (n < cpu_key->on_disk_key.k_dir_id)
50 		return -1;
51 	if (n > cpu_key->on_disk_key.k_dir_id)
52 		return 1;
53 	n = le32_to_cpu(le_key->k_objectid);
54 	if (n < cpu_key->on_disk_key.k_objectid)
55 		return -1;
56 	if (n > cpu_key->on_disk_key.k_objectid)
57 		return 1;
58 	return 0;
59 }
60 
61 /*
62  * k1 is pointer to on-disk structure which is stored in little-endian
63  * form. k2 is pointer to cpu variable.
64  * Compare keys using all 4 key fields.
65  * Returns: -1 if key1 < key2 0
66  * if key1 = key2 1 if key1 > key2
67  */
68 static inline int comp_keys(const struct reiserfs_key *le_key,
69 			    const struct cpu_key *cpu_key)
70 {
71 	int retval;
72 
73 	retval = comp_short_keys(le_key, cpu_key);
74 	if (retval)
75 		return retval;
76 	if (le_key_k_offset(le_key_version(le_key), le_key) <
77 	    cpu_key_k_offset(cpu_key))
78 		return -1;
79 	if (le_key_k_offset(le_key_version(le_key), le_key) >
80 	    cpu_key_k_offset(cpu_key))
81 		return 1;
82 
83 	if (cpu_key->key_length == 3)
84 		return 0;
85 
86 	/* this part is needed only when tail conversion is in progress */
87 	if (le_key_k_type(le_key_version(le_key), le_key) <
88 	    cpu_key_k_type(cpu_key))
89 		return -1;
90 
91 	if (le_key_k_type(le_key_version(le_key), le_key) >
92 	    cpu_key_k_type(cpu_key))
93 		return 1;
94 
95 	return 0;
96 }
97 
98 inline int comp_short_le_keys(const struct reiserfs_key *key1,
99 			      const struct reiserfs_key *key2)
100 {
101 	__u32 *k1_u32, *k2_u32;
102 	int key_length = REISERFS_SHORT_KEY_LEN;
103 
104 	k1_u32 = (__u32 *) key1;
105 	k2_u32 = (__u32 *) key2;
106 	for (; key_length--; ++k1_u32, ++k2_u32) {
107 		if (le32_to_cpu(*k1_u32) < le32_to_cpu(*k2_u32))
108 			return -1;
109 		if (le32_to_cpu(*k1_u32) > le32_to_cpu(*k2_u32))
110 			return 1;
111 	}
112 	return 0;
113 }
114 
115 inline void le_key2cpu_key(struct cpu_key *to, const struct reiserfs_key *from)
116 {
117 	int version;
118 	to->on_disk_key.k_dir_id = le32_to_cpu(from->k_dir_id);
119 	to->on_disk_key.k_objectid = le32_to_cpu(from->k_objectid);
120 
121 	/* find out version of the key */
122 	version = le_key_version(from);
123 	to->version = version;
124 	to->on_disk_key.k_offset = le_key_k_offset(version, from);
125 	to->on_disk_key.k_type = le_key_k_type(version, from);
126 }
127 
128 /*
129  * this does not say which one is bigger, it only returns 1 if keys
130  * are not equal, 0 otherwise
131  */
132 inline int comp_le_keys(const struct reiserfs_key *k1,
133 			const struct reiserfs_key *k2)
134 {
135 	return memcmp(k1, k2, sizeof(struct reiserfs_key));
136 }
137 
138 /**************************************************************************
139  *  Binary search toolkit function                                        *
140  *  Search for an item in the array by the item key                       *
141  *  Returns:    1 if found,  0 if not found;                              *
142  *        *pos = number of the searched element if found, else the        *
143  *        number of the first element that is larger than key.            *
144  **************************************************************************/
145 /*
146  * For those not familiar with binary search: lbound is the leftmost item
147  * that it could be, rbound the rightmost item that it could be.  We examine
148  * the item halfway between lbound and rbound, and that tells us either
149  * that we can increase lbound, or decrease rbound, or that we have found it,
150  * or if lbound <= rbound that there are no possible items, and we have not
151  * found it. With each examination we cut the number of possible items it
152  * could be by one more than half rounded down, or we find it.
153  */
154 static inline int bin_search(const void *key,	/* Key to search for. */
155 			     const void *base,	/* First item in the array. */
156 			     int num,	/* Number of items in the array. */
157 			     /*
158 			      * Item size in the array.  searched. Lest the
159 			      * reader be confused, note that this is crafted
160 			      * as a general function, and when it is applied
161 			      * specifically to the array of item headers in a
162 			      * node, width is actually the item header size
163 			      * not the item size.
164 			      */
165 			     int width,
166 			     int *pos /* Number of the searched for element. */
167     )
168 {
169 	int rbound, lbound, j;
170 
171 	for (j = ((rbound = num - 1) + (lbound = 0)) / 2;
172 	     lbound <= rbound; j = (rbound + lbound) / 2)
173 		switch (comp_keys
174 			((struct reiserfs_key *)((char *)base + j * width),
175 			 (struct cpu_key *)key)) {
176 		case -1:
177 			lbound = j + 1;
178 			continue;
179 		case 1:
180 			rbound = j - 1;
181 			continue;
182 		case 0:
183 			*pos = j;
184 			return ITEM_FOUND;	/* Key found in the array.  */
185 		}
186 
187 	/*
188 	 * bin_search did not find given key, it returns position of key,
189 	 * that is minimal and greater than the given one.
190 	 */
191 	*pos = lbound;
192 	return ITEM_NOT_FOUND;
193 }
194 
195 
196 /* Minimal possible key. It is never in the tree. */
197 const struct reiserfs_key MIN_KEY = { 0, 0, {{0, 0},} };
198 
199 /* Maximal possible key. It is never in the tree. */
200 static const struct reiserfs_key MAX_KEY = {
201 	cpu_to_le32(0xffffffff),
202 	cpu_to_le32(0xffffffff),
203 	{{cpu_to_le32(0xffffffff),
204 	  cpu_to_le32(0xffffffff)},}
205 };
206 
207 /*
208  * Get delimiting key of the buffer by looking for it in the buffers in the
209  * path, starting from the bottom of the path, and going upwards.  We must
210  * check the path's validity at each step.  If the key is not in the path,
211  * there is no delimiting key in the tree (buffer is first or last buffer
212  * in tree), and in this case we return a special key, either MIN_KEY or
213  * MAX_KEY.
214  */
215 static inline const struct reiserfs_key *get_lkey(const struct treepath *chk_path,
216 						  const struct super_block *sb)
217 {
218 	int position, path_offset = chk_path->path_length;
219 	struct buffer_head *parent;
220 
221 	RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
222 	       "PAP-5010: invalid offset in the path");
223 
224 	/* While not higher in path than first element. */
225 	while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
226 
227 		RFALSE(!buffer_uptodate
228 		       (PATH_OFFSET_PBUFFER(chk_path, path_offset)),
229 		       "PAP-5020: parent is not uptodate");
230 
231 		/* Parent at the path is not in the tree now. */
232 		if (!B_IS_IN_TREE
233 		    (parent =
234 		     PATH_OFFSET_PBUFFER(chk_path, path_offset)))
235 			return &MAX_KEY;
236 		/* Check whether position in the parent is correct. */
237 		if ((position =
238 		     PATH_OFFSET_POSITION(chk_path,
239 					  path_offset)) >
240 		    B_NR_ITEMS(parent))
241 			return &MAX_KEY;
242 		/* Check whether parent at the path really points to the child. */
243 		if (B_N_CHILD_NUM(parent, position) !=
244 		    PATH_OFFSET_PBUFFER(chk_path,
245 					path_offset + 1)->b_blocknr)
246 			return &MAX_KEY;
247 		/*
248 		 * Return delimiting key if position in the parent
249 		 * is not equal to zero.
250 		 */
251 		if (position)
252 			return internal_key(parent, position - 1);
253 	}
254 	/* Return MIN_KEY if we are in the root of the buffer tree. */
255 	if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
256 	    b_blocknr == SB_ROOT_BLOCK(sb))
257 		return &MIN_KEY;
258 	return &MAX_KEY;
259 }
260 
261 /* Get delimiting key of the buffer at the path and its right neighbor. */
262 inline const struct reiserfs_key *get_rkey(const struct treepath *chk_path,
263 					   const struct super_block *sb)
264 {
265 	int position, path_offset = chk_path->path_length;
266 	struct buffer_head *parent;
267 
268 	RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
269 	       "PAP-5030: invalid offset in the path");
270 
271 	while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
272 
273 		RFALSE(!buffer_uptodate
274 		       (PATH_OFFSET_PBUFFER(chk_path, path_offset)),
275 		       "PAP-5040: parent is not uptodate");
276 
277 		/* Parent at the path is not in the tree now. */
278 		if (!B_IS_IN_TREE
279 		    (parent =
280 		     PATH_OFFSET_PBUFFER(chk_path, path_offset)))
281 			return &MIN_KEY;
282 		/* Check whether position in the parent is correct. */
283 		if ((position =
284 		     PATH_OFFSET_POSITION(chk_path,
285 					  path_offset)) >
286 		    B_NR_ITEMS(parent))
287 			return &MIN_KEY;
288 		/*
289 		 * Check whether parent at the path really points
290 		 * to the child.
291 		 */
292 		if (B_N_CHILD_NUM(parent, position) !=
293 		    PATH_OFFSET_PBUFFER(chk_path,
294 					path_offset + 1)->b_blocknr)
295 			return &MIN_KEY;
296 
297 		/*
298 		 * Return delimiting key if position in the parent
299 		 * is not the last one.
300 		 */
301 		if (position != B_NR_ITEMS(parent))
302 			return internal_key(parent, position);
303 	}
304 
305 	/* Return MAX_KEY if we are in the root of the buffer tree. */
306 	if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
307 	    b_blocknr == SB_ROOT_BLOCK(sb))
308 		return &MAX_KEY;
309 	return &MIN_KEY;
310 }
311 
312 /*
313  * Check whether a key is contained in the tree rooted from a buffer at a path.
314  * This works by looking at the left and right delimiting keys for the buffer
315  * in the last path_element in the path.  These delimiting keys are stored
316  * at least one level above that buffer in the tree. If the buffer is the
317  * first or last node in the tree order then one of the delimiting keys may
318  * be absent, and in this case get_lkey and get_rkey return a special key
319  * which is MIN_KEY or MAX_KEY.
320  */
321 static inline int key_in_buffer(
322 				/* Path which should be checked. */
323 				struct treepath *chk_path,
324 				/* Key which should be checked. */
325 				const struct cpu_key *key,
326 				struct super_block *sb
327     )
328 {
329 
330 	RFALSE(!key || chk_path->path_length < FIRST_PATH_ELEMENT_OFFSET
331 	       || chk_path->path_length > MAX_HEIGHT,
332 	       "PAP-5050: pointer to the key(%p) is NULL or invalid path length(%d)",
333 	       key, chk_path->path_length);
334 	RFALSE(!PATH_PLAST_BUFFER(chk_path)->b_bdev,
335 	       "PAP-5060: device must not be NODEV");
336 
337 	if (comp_keys(get_lkey(chk_path, sb), key) == 1)
338 		/* left delimiting key is bigger, that the key we look for */
339 		return 0;
340 	/*  if ( comp_keys(key, get_rkey(chk_path, sb)) != -1 ) */
341 	if (comp_keys(get_rkey(chk_path, sb), key) != 1)
342 		/* key must be less than right delimitiing key */
343 		return 0;
344 	return 1;
345 }
346 
347 int reiserfs_check_path(struct treepath *p)
348 {
349 	RFALSE(p->path_length != ILLEGAL_PATH_ELEMENT_OFFSET,
350 	       "path not properly relsed");
351 	return 0;
352 }
353 
354 /*
355  * Drop the reference to each buffer in a path and restore
356  * dirty bits clean when preparing the buffer for the log.
357  * This version should only be called from fix_nodes()
358  */
359 void pathrelse_and_restore(struct super_block *sb,
360 			   struct treepath *search_path)
361 {
362 	int path_offset = search_path->path_length;
363 
364 	RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
365 	       "clm-4000: invalid path offset");
366 
367 	while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET) {
368 		struct buffer_head *bh;
369 		bh = PATH_OFFSET_PBUFFER(search_path, path_offset--);
370 		reiserfs_restore_prepared_buffer(sb, bh);
371 		brelse(bh);
372 	}
373 	search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
374 }
375 
376 /* Drop the reference to each buffer in a path */
377 void pathrelse(struct treepath *search_path)
378 {
379 	int path_offset = search_path->path_length;
380 
381 	RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
382 	       "PAP-5090: invalid path offset");
383 
384 	while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET)
385 		brelse(PATH_OFFSET_PBUFFER(search_path, path_offset--));
386 
387 	search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
388 }
389 
390 static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
391 {
392 	struct block_head *blkh;
393 	struct item_head *ih;
394 	int used_space;
395 	int prev_location;
396 	int i;
397 	int nr;
398 
399 	blkh = (struct block_head *)buf;
400 	if (blkh_level(blkh) != DISK_LEAF_NODE_LEVEL) {
401 		reiserfs_warning(NULL, "reiserfs-5080",
402 				 "this should be caught earlier");
403 		return 0;
404 	}
405 
406 	nr = blkh_nr_item(blkh);
407 	if (nr < 1 || nr > ((blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN))) {
408 		/* item number is too big or too small */
409 		reiserfs_warning(NULL, "reiserfs-5081",
410 				 "nr_item seems wrong: %z", bh);
411 		return 0;
412 	}
413 	ih = (struct item_head *)(buf + BLKH_SIZE) + nr - 1;
414 	used_space = BLKH_SIZE + IH_SIZE * nr + (blocksize - ih_location(ih));
415 
416 	/* free space does not match to calculated amount of use space */
417 	if (used_space != blocksize - blkh_free_space(blkh)) {
418 		reiserfs_warning(NULL, "reiserfs-5082",
419 				 "free space seems wrong: %z", bh);
420 		return 0;
421 	}
422 	/*
423 	 * FIXME: it is_leaf will hit performance too much - we may have
424 	 * return 1 here
425 	 */
426 
427 	/* check tables of item heads */
428 	ih = (struct item_head *)(buf + BLKH_SIZE);
429 	prev_location = blocksize;
430 	for (i = 0; i < nr; i++, ih++) {
431 		if (le_ih_k_type(ih) == TYPE_ANY) {
432 			reiserfs_warning(NULL, "reiserfs-5083",
433 					 "wrong item type for item %h",
434 					 ih);
435 			return 0;
436 		}
437 		if (ih_location(ih) >= blocksize
438 		    || ih_location(ih) < IH_SIZE * nr) {
439 			reiserfs_warning(NULL, "reiserfs-5084",
440 					 "item location seems wrong: %h",
441 					 ih);
442 			return 0;
443 		}
444 		if (ih_item_len(ih) < 1
445 		    || ih_item_len(ih) > MAX_ITEM_LEN(blocksize)) {
446 			reiserfs_warning(NULL, "reiserfs-5085",
447 					 "item length seems wrong: %h",
448 					 ih);
449 			return 0;
450 		}
451 		if (prev_location - ih_location(ih) != ih_item_len(ih)) {
452 			reiserfs_warning(NULL, "reiserfs-5086",
453 					 "item location seems wrong "
454 					 "(second one): %h", ih);
455 			return 0;
456 		}
457 		prev_location = ih_location(ih);
458 	}
459 
460 	/* one may imagine many more checks */
461 	return 1;
462 }
463 
464 /* returns 1 if buf looks like an internal node, 0 otherwise */
465 static int is_internal(char *buf, int blocksize, struct buffer_head *bh)
466 {
467 	struct block_head *blkh;
468 	int nr;
469 	int used_space;
470 
471 	blkh = (struct block_head *)buf;
472 	nr = blkh_level(blkh);
473 	if (nr <= DISK_LEAF_NODE_LEVEL || nr > MAX_HEIGHT) {
474 		/* this level is not possible for internal nodes */
475 		reiserfs_warning(NULL, "reiserfs-5087",
476 				 "this should be caught earlier");
477 		return 0;
478 	}
479 
480 	nr = blkh_nr_item(blkh);
481 	/* for internal which is not root we might check min number of keys */
482 	if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
483 		reiserfs_warning(NULL, "reiserfs-5088",
484 				 "number of key seems wrong: %z", bh);
485 		return 0;
486 	}
487 
488 	used_space = BLKH_SIZE + KEY_SIZE * nr + DC_SIZE * (nr + 1);
489 	if (used_space != blocksize - blkh_free_space(blkh)) {
490 		reiserfs_warning(NULL, "reiserfs-5089",
491 				 "free space seems wrong: %z", bh);
492 		return 0;
493 	}
494 
495 	/* one may imagine many more checks */
496 	return 1;
497 }
498 
499 /*
500  * make sure that bh contains formatted node of reiserfs tree of
501  * 'level'-th level
502  */
503 static int is_tree_node(struct buffer_head *bh, int level)
504 {
505 	if (B_LEVEL(bh) != level) {
506 		reiserfs_warning(NULL, "reiserfs-5090", "node level %d does "
507 				 "not match to the expected one %d",
508 				 B_LEVEL(bh), level);
509 		return 0;
510 	}
511 	if (level == DISK_LEAF_NODE_LEVEL)
512 		return is_leaf(bh->b_data, bh->b_size, bh);
513 
514 	return is_internal(bh->b_data, bh->b_size, bh);
515 }
516 
517 #define SEARCH_BY_KEY_READA 16
518 
519 /*
520  * The function is NOT SCHEDULE-SAFE!
521  * It might unlock the write lock if we needed to wait for a block
522  * to be read. Note that in this case it won't recover the lock to avoid
523  * high contention resulting from too much lock requests, especially
524  * the caller (search_by_key) will perform other schedule-unsafe
525  * operations just after calling this function.
526  *
527  * @return depth of lock to be restored after read completes
528  */
529 static int search_by_key_reada(struct super_block *s,
530 				struct buffer_head **bh,
531 				b_blocknr_t *b, int num)
532 {
533 	int i, j;
534 	int depth = -1;
535 
536 	for (i = 0; i < num; i++) {
537 		bh[i] = sb_getblk(s, b[i]);
538 	}
539 	/*
540 	 * We are going to read some blocks on which we
541 	 * have a reference. It's safe, though we might be
542 	 * reading blocks concurrently changed if we release
543 	 * the lock. But it's still fine because we check later
544 	 * if the tree changed
545 	 */
546 	for (j = 0; j < i; j++) {
547 		/*
548 		 * note, this needs attention if we are getting rid of the BKL
549 		 * you have to make sure the prepared bit isn't set on this
550 		 * buffer
551 		 */
552 		if (!buffer_uptodate(bh[j])) {
553 			if (depth == -1)
554 				depth = reiserfs_write_unlock_nested(s);
555 			ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, bh + j);
556 		}
557 		brelse(bh[j]);
558 	}
559 	return depth;
560 }
561 
562 /*
563  * This function fills up the path from the root to the leaf as it
564  * descends the tree looking for the key.  It uses reiserfs_bread to
565  * try to find buffers in the cache given their block number.  If it
566  * does not find them in the cache it reads them from disk.  For each
567  * node search_by_key finds using reiserfs_bread it then uses
568  * bin_search to look through that node.  bin_search will find the
569  * position of the block_number of the next node if it is looking
570  * through an internal node.  If it is looking through a leaf node
571  * bin_search will find the position of the item which has key either
572  * equal to given key, or which is the maximal key less than the given
573  * key.  search_by_key returns a path that must be checked for the
574  * correctness of the top of the path but need not be checked for the
575  * correctness of the bottom of the path
576  */
577 /*
578  * search_by_key - search for key (and item) in stree
579  * @sb: superblock
580  * @key: pointer to key to search for
581  * @search_path: Allocated and initialized struct treepath; Returned filled
582  *		 on success.
583  * @stop_level: How far down the tree to search, Use DISK_LEAF_NODE_LEVEL to
584  *		stop at leaf level.
585  *
586  * The function is NOT SCHEDULE-SAFE!
587  */
588 int search_by_key(struct super_block *sb, const struct cpu_key *key,
589 		  struct treepath *search_path, int stop_level)
590 {
591 	b_blocknr_t block_number;
592 	int expected_level;
593 	struct buffer_head *bh;
594 	struct path_element *last_element;
595 	int node_level, retval;
596 	int fs_gen;
597 	struct buffer_head *reada_bh[SEARCH_BY_KEY_READA];
598 	b_blocknr_t reada_blocks[SEARCH_BY_KEY_READA];
599 	int reada_count = 0;
600 
601 #ifdef CONFIG_REISERFS_CHECK
602 	int repeat_counter = 0;
603 #endif
604 
605 	PROC_INFO_INC(sb, search_by_key);
606 
607 	/*
608 	 * As we add each node to a path we increase its count.  This means
609 	 * that we must be careful to release all nodes in a path before we
610 	 * either discard the path struct or re-use the path struct, as we
611 	 * do here.
612 	 */
613 
614 	pathrelse(search_path);
615 
616 	/*
617 	 * With each iteration of this loop we search through the items in the
618 	 * current node, and calculate the next current node(next path element)
619 	 * for the next iteration of this loop..
620 	 */
621 	block_number = SB_ROOT_BLOCK(sb);
622 	expected_level = -1;
623 	while (1) {
624 
625 #ifdef CONFIG_REISERFS_CHECK
626 		if (!(++repeat_counter % 50000))
627 			reiserfs_warning(sb, "PAP-5100",
628 					 "%s: there were %d iterations of "
629 					 "while loop looking for key %K",
630 					 current->comm, repeat_counter,
631 					 key);
632 #endif
633 
634 		/* prep path to have another element added to it. */
635 		last_element =
636 		    PATH_OFFSET_PELEMENT(search_path,
637 					 ++search_path->path_length);
638 		fs_gen = get_generation(sb);
639 
640 		/*
641 		 * Read the next tree node, and set the last element
642 		 * in the path to have a pointer to it.
643 		 */
644 		if ((bh = last_element->pe_buffer =
645 		     sb_getblk(sb, block_number))) {
646 
647 			/*
648 			 * We'll need to drop the lock if we encounter any
649 			 * buffers that need to be read. If all of them are
650 			 * already up to date, we don't need to drop the lock.
651 			 */
652 			int depth = -1;
653 
654 			if (!buffer_uptodate(bh) && reada_count > 1)
655 				depth = search_by_key_reada(sb, reada_bh,
656 						    reada_blocks, reada_count);
657 
658 			if (!buffer_uptodate(bh) && depth == -1)
659 				depth = reiserfs_write_unlock_nested(sb);
660 
661 			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
662 			wait_on_buffer(bh);
663 
664 			if (depth != -1)
665 				reiserfs_write_lock_nested(sb, depth);
666 			if (!buffer_uptodate(bh))
667 				goto io_error;
668 		} else {
669 io_error:
670 			search_path->path_length--;
671 			pathrelse(search_path);
672 			return IO_ERROR;
673 		}
674 		reada_count = 0;
675 		if (expected_level == -1)
676 			expected_level = SB_TREE_HEIGHT(sb);
677 		expected_level--;
678 
679 		/*
680 		 * It is possible that schedule occurred. We must check
681 		 * whether the key to search is still in the tree rooted
682 		 * from the current buffer. If not then repeat search
683 		 * from the root.
684 		 */
685 		if (fs_changed(fs_gen, sb) &&
686 		    (!B_IS_IN_TREE(bh) ||
687 		     B_LEVEL(bh) != expected_level ||
688 		     !key_in_buffer(search_path, key, sb))) {
689 			PROC_INFO_INC(sb, search_by_key_fs_changed);
690 			PROC_INFO_INC(sb, search_by_key_restarted);
691 			PROC_INFO_INC(sb,
692 				      sbk_restarted[expected_level - 1]);
693 			pathrelse(search_path);
694 
695 			/*
696 			 * Get the root block number so that we can
697 			 * repeat the search starting from the root.
698 			 */
699 			block_number = SB_ROOT_BLOCK(sb);
700 			expected_level = -1;
701 
702 			/* repeat search from the root */
703 			continue;
704 		}
705 
706 		/*
707 		 * only check that the key is in the buffer if key is not
708 		 * equal to the MAX_KEY. Latter case is only possible in
709 		 * "finish_unfinished()" processing during mount.
710 		 */
711 		RFALSE(comp_keys(&MAX_KEY, key) &&
712 		       !key_in_buffer(search_path, key, sb),
713 		       "PAP-5130: key is not in the buffer");
714 #ifdef CONFIG_REISERFS_CHECK
715 		if (REISERFS_SB(sb)->cur_tb) {
716 			print_cur_tb("5140");
717 			reiserfs_panic(sb, "PAP-5140",
718 				       "schedule occurred in do_balance!");
719 		}
720 #endif
721 
722 		/*
723 		 * make sure, that the node contents look like a node of
724 		 * certain level
725 		 */
726 		if (!is_tree_node(bh, expected_level)) {
727 			reiserfs_error(sb, "vs-5150",
728 				       "invalid format found in block %ld. "
729 				       "Fsck?", bh->b_blocknr);
730 			pathrelse(search_path);
731 			return IO_ERROR;
732 		}
733 
734 		/* ok, we have acquired next formatted node in the tree */
735 		node_level = B_LEVEL(bh);
736 
737 		PROC_INFO_BH_STAT(sb, bh, node_level - 1);
738 
739 		RFALSE(node_level < stop_level,
740 		       "vs-5152: tree level (%d) is less than stop level (%d)",
741 		       node_level, stop_level);
742 
743 		retval = bin_search(key, item_head(bh, 0),
744 				      B_NR_ITEMS(bh),
745 				      (node_level ==
746 				       DISK_LEAF_NODE_LEVEL) ? IH_SIZE :
747 				      KEY_SIZE,
748 				      &last_element->pe_position);
749 		if (node_level == stop_level) {
750 			return retval;
751 		}
752 
753 		/* we are not in the stop level */
754 		/*
755 		 * item has been found, so we choose the pointer which
756 		 * is to the right of the found one
757 		 */
758 		if (retval == ITEM_FOUND)
759 			last_element->pe_position++;
760 
761 		/*
762 		 * if item was not found we choose the position which is to
763 		 * the left of the found item. This requires no code,
764 		 * bin_search did it already.
765 		 */
766 
767 		/*
768 		 * So we have chosen a position in the current node which is
769 		 * an internal node.  Now we calculate child block number by
770 		 * position in the node.
771 		 */
772 		block_number =
773 		    B_N_CHILD_NUM(bh, last_element->pe_position);
774 
775 		/*
776 		 * if we are going to read leaf nodes, try for read
777 		 * ahead as well
778 		 */
779 		if ((search_path->reada & PATH_READA) &&
780 		    node_level == DISK_LEAF_NODE_LEVEL + 1) {
781 			int pos = last_element->pe_position;
782 			int limit = B_NR_ITEMS(bh);
783 			struct reiserfs_key *le_key;
784 
785 			if (search_path->reada & PATH_READA_BACK)
786 				limit = 0;
787 			while (reada_count < SEARCH_BY_KEY_READA) {
788 				if (pos == limit)
789 					break;
790 				reada_blocks[reada_count++] =
791 				    B_N_CHILD_NUM(bh, pos);
792 				if (search_path->reada & PATH_READA_BACK)
793 					pos--;
794 				else
795 					pos++;
796 
797 				/*
798 				 * check to make sure we're in the same object
799 				 */
800 				le_key = internal_key(bh, pos);
801 				if (le32_to_cpu(le_key->k_objectid) !=
802 				    key->on_disk_key.k_objectid) {
803 					break;
804 				}
805 			}
806 		}
807 	}
808 }
809 
810 /*
811  * Form the path to an item and position in this item which contains
812  * file byte defined by key. If there is no such item
813  * corresponding to the key, we point the path to the item with
814  * maximal key less than key, and *pos_in_item is set to one
815  * past the last entry/byte in the item.  If searching for entry in a
816  * directory item, and it is not found, *pos_in_item is set to one
817  * entry more than the entry with maximal key which is less than the
818  * sought key.
819  *
820  * Note that if there is no entry in this same node which is one more,
821  * then we point to an imaginary entry.  for direct items, the
822  * position is in units of bytes, for indirect items the position is
823  * in units of blocknr entries, for directory items the position is in
824  * units of directory entries.
825  */
826 /* The function is NOT SCHEDULE-SAFE! */
827 int search_for_position_by_key(struct super_block *sb,
828 			       /* Key to search (cpu variable) */
829 			       const struct cpu_key *p_cpu_key,
830 			       /* Filled up by this function. */
831 			       struct treepath *search_path)
832 {
833 	struct item_head *p_le_ih;	/* pointer to on-disk structure */
834 	int blk_size;
835 	loff_t item_offset, offset;
836 	struct reiserfs_dir_entry de;
837 	int retval;
838 
839 	/* If searching for directory entry. */
840 	if (is_direntry_cpu_key(p_cpu_key))
841 		return search_by_entry_key(sb, p_cpu_key, search_path,
842 					   &de);
843 
844 	/* If not searching for directory entry. */
845 
846 	/* If item is found. */
847 	retval = search_item(sb, p_cpu_key, search_path);
848 	if (retval == IO_ERROR)
849 		return retval;
850 	if (retval == ITEM_FOUND) {
851 
852 		RFALSE(!ih_item_len
853 		       (item_head
854 			(PATH_PLAST_BUFFER(search_path),
855 			 PATH_LAST_POSITION(search_path))),
856 		       "PAP-5165: item length equals zero");
857 
858 		pos_in_item(search_path) = 0;
859 		return POSITION_FOUND;
860 	}
861 
862 	RFALSE(!PATH_LAST_POSITION(search_path),
863 	       "PAP-5170: position equals zero");
864 
865 	/* Item is not found. Set path to the previous item. */
866 	p_le_ih =
867 	    item_head(PATH_PLAST_BUFFER(search_path),
868 			   --PATH_LAST_POSITION(search_path));
869 	blk_size = sb->s_blocksize;
870 
871 	if (comp_short_keys(&p_le_ih->ih_key, p_cpu_key))
872 		return FILE_NOT_FOUND;
873 
874 	/* FIXME: quite ugly this far */
875 
876 	item_offset = le_ih_k_offset(p_le_ih);
877 	offset = cpu_key_k_offset(p_cpu_key);
878 
879 	/* Needed byte is contained in the item pointed to by the path. */
880 	if (item_offset <= offset &&
881 	    item_offset + op_bytes_number(p_le_ih, blk_size) > offset) {
882 		pos_in_item(search_path) = offset - item_offset;
883 		if (is_indirect_le_ih(p_le_ih)) {
884 			pos_in_item(search_path) /= blk_size;
885 		}
886 		return POSITION_FOUND;
887 	}
888 
889 	/*
890 	 * Needed byte is not contained in the item pointed to by the
891 	 * path. Set pos_in_item out of the item.
892 	 */
893 	if (is_indirect_le_ih(p_le_ih))
894 		pos_in_item(search_path) =
895 		    ih_item_len(p_le_ih) / UNFM_P_SIZE;
896 	else
897 		pos_in_item(search_path) = ih_item_len(p_le_ih);
898 
899 	return POSITION_NOT_FOUND;
900 }
901 
902 /* Compare given item and item pointed to by the path. */
903 int comp_items(const struct item_head *stored_ih, const struct treepath *path)
904 {
905 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
906 	struct item_head *ih;
907 
908 	/* Last buffer at the path is not in the tree. */
909 	if (!B_IS_IN_TREE(bh))
910 		return 1;
911 
912 	/* Last path position is invalid. */
913 	if (PATH_LAST_POSITION(path) >= B_NR_ITEMS(bh))
914 		return 1;
915 
916 	/* we need only to know, whether it is the same item */
917 	ih = tp_item_head(path);
918 	return memcmp(stored_ih, ih, IH_SIZE);
919 }
920 
921 /* prepare for delete or cut of direct item */
922 static inline int prepare_for_direct_item(struct treepath *path,
923 					  struct item_head *le_ih,
924 					  struct inode *inode,
925 					  loff_t new_file_length, int *cut_size)
926 {
927 	loff_t round_len;
928 
929 	if (new_file_length == max_reiserfs_offset(inode)) {
930 		/* item has to be deleted */
931 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
932 		return M_DELETE;
933 	}
934 	/* new file gets truncated */
935 	if (get_inode_item_key_version(inode) == KEY_FORMAT_3_6) {
936 		round_len = ROUND_UP(new_file_length);
937 		/* this was new_file_length < le_ih ... */
938 		if (round_len < le_ih_k_offset(le_ih)) {
939 			*cut_size = -(IH_SIZE + ih_item_len(le_ih));
940 			return M_DELETE;	/* Delete this item. */
941 		}
942 		/* Calculate first position and size for cutting from item. */
943 		pos_in_item(path) = round_len - (le_ih_k_offset(le_ih) - 1);
944 		*cut_size = -(ih_item_len(le_ih) - pos_in_item(path));
945 
946 		return M_CUT;	/* Cut from this item. */
947 	}
948 
949 	/* old file: items may have any length */
950 
951 	if (new_file_length < le_ih_k_offset(le_ih)) {
952 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
953 		return M_DELETE;	/* Delete this item. */
954 	}
955 
956 	/* Calculate first position and size for cutting from item. */
957 	*cut_size = -(ih_item_len(le_ih) -
958 		      (pos_in_item(path) =
959 		       new_file_length + 1 - le_ih_k_offset(le_ih)));
960 	return M_CUT;		/* Cut from this item. */
961 }
962 
963 static inline int prepare_for_direntry_item(struct treepath *path,
964 					    struct item_head *le_ih,
965 					    struct inode *inode,
966 					    loff_t new_file_length,
967 					    int *cut_size)
968 {
969 	if (le_ih_k_offset(le_ih) == DOT_OFFSET &&
970 	    new_file_length == max_reiserfs_offset(inode)) {
971 		RFALSE(ih_entry_count(le_ih) != 2,
972 		       "PAP-5220: incorrect empty directory item (%h)", le_ih);
973 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
974 		/* Delete the directory item containing "." and ".." entry. */
975 		return M_DELETE;
976 	}
977 
978 	if (ih_entry_count(le_ih) == 1) {
979 		/*
980 		 * Delete the directory item such as there is one record only
981 		 * in this item
982 		 */
983 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
984 		return M_DELETE;
985 	}
986 
987 	/* Cut one record from the directory item. */
988 	*cut_size =
989 	    -(DEH_SIZE +
990 	      entry_length(get_last_bh(path), le_ih, pos_in_item(path)));
991 	return M_CUT;
992 }
993 
994 #define JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD (2 * JOURNAL_PER_BALANCE_CNT + 1)
995 
996 /*
997  * If the path points to a directory or direct item, calculate mode
998  * and the size cut, for balance.
999  * If the path points to an indirect item, remove some number of its
1000  * unformatted nodes.
1001  * In case of file truncate calculate whether this item must be
1002  * deleted/truncated or last unformatted node of this item will be
1003  * converted to a direct item.
1004  * This function returns a determination of what balance mode the
1005  * calling function should employ.
1006  */
1007 static char prepare_for_delete_or_cut(struct reiserfs_transaction_handle *th,
1008 				      struct inode *inode,
1009 				      struct treepath *path,
1010 				      const struct cpu_key *item_key,
1011 				      /*
1012 				       * Number of unformatted nodes
1013 				       * which were removed from end
1014 				       * of the file.
1015 				       */
1016 				      int *removed,
1017 				      int *cut_size,
1018 				      /* MAX_KEY_OFFSET in case of delete. */
1019 				      unsigned long long new_file_length
1020     )
1021 {
1022 	struct super_block *sb = inode->i_sb;
1023 	struct item_head *p_le_ih = tp_item_head(path);
1024 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
1025 
1026 	BUG_ON(!th->t_trans_id);
1027 
1028 	/* Stat_data item. */
1029 	if (is_statdata_le_ih(p_le_ih)) {
1030 
1031 		RFALSE(new_file_length != max_reiserfs_offset(inode),
1032 		       "PAP-5210: mode must be M_DELETE");
1033 
1034 		*cut_size = -(IH_SIZE + ih_item_len(p_le_ih));
1035 		return M_DELETE;
1036 	}
1037 
1038 	/* Directory item. */
1039 	if (is_direntry_le_ih(p_le_ih))
1040 		return prepare_for_direntry_item(path, p_le_ih, inode,
1041 						 new_file_length,
1042 						 cut_size);
1043 
1044 	/* Direct item. */
1045 	if (is_direct_le_ih(p_le_ih))
1046 		return prepare_for_direct_item(path, p_le_ih, inode,
1047 					       new_file_length, cut_size);
1048 
1049 	/* Case of an indirect item. */
1050 	{
1051 	    int blk_size = sb->s_blocksize;
1052 	    struct item_head s_ih;
1053 	    int need_re_search;
1054 	    int delete = 0;
1055 	    int result = M_CUT;
1056 	    int pos = 0;
1057 
1058 	    if ( new_file_length == max_reiserfs_offset (inode) ) {
1059 		/*
1060 		 * prepare_for_delete_or_cut() is called by
1061 		 * reiserfs_delete_item()
1062 		 */
1063 		new_file_length = 0;
1064 		delete = 1;
1065 	    }
1066 
1067 	    do {
1068 		need_re_search = 0;
1069 		*cut_size = 0;
1070 		bh = PATH_PLAST_BUFFER(path);
1071 		copy_item_head(&s_ih, tp_item_head(path));
1072 		pos = I_UNFM_NUM(&s_ih);
1073 
1074 		while (le_ih_k_offset (&s_ih) + (pos - 1) * blk_size > new_file_length) {
1075 		    __le32 *unfm;
1076 		    __u32 block;
1077 
1078 		    /*
1079 		     * Each unformatted block deletion may involve
1080 		     * one additional bitmap block into the transaction,
1081 		     * thereby the initial journal space reservation
1082 		     * might not be enough.
1083 		     */
1084 		    if (!delete && (*cut_size) != 0 &&
1085 			reiserfs_transaction_free_space(th) < JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD)
1086 			break;
1087 
1088 		    unfm = (__le32 *)ih_item_body(bh, &s_ih) + pos - 1;
1089 		    block = get_block_num(unfm, 0);
1090 
1091 		    if (block != 0) {
1092 			reiserfs_prepare_for_journal(sb, bh, 1);
1093 			put_block_num(unfm, 0, 0);
1094 			journal_mark_dirty(th, bh);
1095 			reiserfs_free_block(th, inode, block, 1);
1096 		    }
1097 
1098 		    reiserfs_cond_resched(sb);
1099 
1100 		    if (item_moved (&s_ih, path))  {
1101 			need_re_search = 1;
1102 			break;
1103 		    }
1104 
1105 		    pos --;
1106 		    (*removed)++;
1107 		    (*cut_size) -= UNFM_P_SIZE;
1108 
1109 		    if (pos == 0) {
1110 			(*cut_size) -= IH_SIZE;
1111 			result = M_DELETE;
1112 			break;
1113 		    }
1114 		}
1115 		/*
1116 		 * a trick.  If the buffer has been logged, this will
1117 		 * do nothing.  If we've broken the loop without logging
1118 		 * it, it will restore the buffer
1119 		 */
1120 		reiserfs_restore_prepared_buffer(sb, bh);
1121 	    } while (need_re_search &&
1122 		     search_for_position_by_key(sb, item_key, path) == POSITION_FOUND);
1123 	    pos_in_item(path) = pos * UNFM_P_SIZE;
1124 
1125 	    if (*cut_size == 0) {
1126 		/*
1127 		 * Nothing was cut. maybe convert last unformatted node to the
1128 		 * direct item?
1129 		 */
1130 		result = M_CONVERT;
1131 	    }
1132 	    return result;
1133 	}
1134 }
1135 
1136 /* Calculate number of bytes which will be deleted or cut during balance */
1137 static int calc_deleted_bytes_number(struct tree_balance *tb, char mode)
1138 {
1139 	int del_size;
1140 	struct item_head *p_le_ih = tp_item_head(tb->tb_path);
1141 
1142 	if (is_statdata_le_ih(p_le_ih))
1143 		return 0;
1144 
1145 	del_size =
1146 	    (mode ==
1147 	     M_DELETE) ? ih_item_len(p_le_ih) : -tb->insert_size[0];
1148 	if (is_direntry_le_ih(p_le_ih)) {
1149 		/*
1150 		 * return EMPTY_DIR_SIZE; We delete emty directories only.
1151 		 * we can't use EMPTY_DIR_SIZE, as old format dirs have a
1152 		 * different empty size.  ick. FIXME, is this right?
1153 		 */
1154 		return del_size;
1155 	}
1156 
1157 	if (is_indirect_le_ih(p_le_ih))
1158 		del_size = (del_size / UNFM_P_SIZE) *
1159 				(PATH_PLAST_BUFFER(tb->tb_path)->b_size);
1160 	return del_size;
1161 }
1162 
1163 static void init_tb_struct(struct reiserfs_transaction_handle *th,
1164 			   struct tree_balance *tb,
1165 			   struct super_block *sb,
1166 			   struct treepath *path, int size)
1167 {
1168 
1169 	BUG_ON(!th->t_trans_id);
1170 
1171 	memset(tb, '\0', sizeof(struct tree_balance));
1172 	tb->transaction_handle = th;
1173 	tb->tb_sb = sb;
1174 	tb->tb_path = path;
1175 	PATH_OFFSET_PBUFFER(path, ILLEGAL_PATH_ELEMENT_OFFSET) = NULL;
1176 	PATH_OFFSET_POSITION(path, ILLEGAL_PATH_ELEMENT_OFFSET) = 0;
1177 	tb->insert_size[0] = size;
1178 }
1179 
1180 void padd_item(char *item, int total_length, int length)
1181 {
1182 	int i;
1183 
1184 	for (i = total_length; i > length;)
1185 		item[--i] = 0;
1186 }
1187 
1188 #ifdef REISERQUOTA_DEBUG
1189 char key2type(struct reiserfs_key *ih)
1190 {
1191 	if (is_direntry_le_key(2, ih))
1192 		return 'd';
1193 	if (is_direct_le_key(2, ih))
1194 		return 'D';
1195 	if (is_indirect_le_key(2, ih))
1196 		return 'i';
1197 	if (is_statdata_le_key(2, ih))
1198 		return 's';
1199 	return 'u';
1200 }
1201 
1202 char head2type(struct item_head *ih)
1203 {
1204 	if (is_direntry_le_ih(ih))
1205 		return 'd';
1206 	if (is_direct_le_ih(ih))
1207 		return 'D';
1208 	if (is_indirect_le_ih(ih))
1209 		return 'i';
1210 	if (is_statdata_le_ih(ih))
1211 		return 's';
1212 	return 'u';
1213 }
1214 #endif
1215 
1216 /*
1217  * Delete object item.
1218  * th       - active transaction handle
1219  * path     - path to the deleted item
1220  * item_key - key to search for the deleted item
1221  * indode   - used for updating i_blocks and quotas
1222  * un_bh    - NULL or unformatted node pointer
1223  */
1224 int reiserfs_delete_item(struct reiserfs_transaction_handle *th,
1225 			 struct treepath *path, const struct cpu_key *item_key,
1226 			 struct inode *inode, struct buffer_head *un_bh)
1227 {
1228 	struct super_block *sb = inode->i_sb;
1229 	struct tree_balance s_del_balance;
1230 	struct item_head s_ih;
1231 	struct item_head *q_ih;
1232 	int quota_cut_bytes;
1233 	int ret_value, del_size, removed;
1234 	int depth;
1235 
1236 #ifdef CONFIG_REISERFS_CHECK
1237 	char mode;
1238 	int iter = 0;
1239 #endif
1240 
1241 	BUG_ON(!th->t_trans_id);
1242 
1243 	init_tb_struct(th, &s_del_balance, sb, path,
1244 		       0 /*size is unknown */ );
1245 
1246 	while (1) {
1247 		removed = 0;
1248 
1249 #ifdef CONFIG_REISERFS_CHECK
1250 		iter++;
1251 		mode =
1252 #endif
1253 		    prepare_for_delete_or_cut(th, inode, path,
1254 					      item_key, &removed,
1255 					      &del_size,
1256 					      max_reiserfs_offset(inode));
1257 
1258 		RFALSE(mode != M_DELETE, "PAP-5320: mode must be M_DELETE");
1259 
1260 		copy_item_head(&s_ih, tp_item_head(path));
1261 		s_del_balance.insert_size[0] = del_size;
1262 
1263 		ret_value = fix_nodes(M_DELETE, &s_del_balance, NULL, NULL);
1264 		if (ret_value != REPEAT_SEARCH)
1265 			break;
1266 
1267 		PROC_INFO_INC(sb, delete_item_restarted);
1268 
1269 		/* file system changed, repeat search */
1270 		ret_value =
1271 		    search_for_position_by_key(sb, item_key, path);
1272 		if (ret_value == IO_ERROR)
1273 			break;
1274 		if (ret_value == FILE_NOT_FOUND) {
1275 			reiserfs_warning(sb, "vs-5340",
1276 					 "no items of the file %K found",
1277 					 item_key);
1278 			break;
1279 		}
1280 	}			/* while (1) */
1281 
1282 	if (ret_value != CARRY_ON) {
1283 		unfix_nodes(&s_del_balance);
1284 		return 0;
1285 	}
1286 
1287 	/* reiserfs_delete_item returns item length when success */
1288 	ret_value = calc_deleted_bytes_number(&s_del_balance, M_DELETE);
1289 	q_ih = tp_item_head(path);
1290 	quota_cut_bytes = ih_item_len(q_ih);
1291 
1292 	/*
1293 	 * hack so the quota code doesn't have to guess if the file has a
1294 	 * tail.  On tail insert, we allocate quota for 1 unformatted node.
1295 	 * We test the offset because the tail might have been
1296 	 * split into multiple items, and we only want to decrement for
1297 	 * the unfm node once
1298 	 */
1299 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(q_ih)) {
1300 		if ((le_ih_k_offset(q_ih) & (sb->s_blocksize - 1)) == 1) {
1301 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1302 		} else {
1303 			quota_cut_bytes = 0;
1304 		}
1305 	}
1306 
1307 	if (un_bh) {
1308 		int off;
1309 		char *data;
1310 
1311 		/*
1312 		 * We are in direct2indirect conversion, so move tail contents
1313 		 * to the unformatted node
1314 		 */
1315 		/*
1316 		 * note, we do the copy before preparing the buffer because we
1317 		 * don't care about the contents of the unformatted node yet.
1318 		 * the only thing we really care about is the direct item's
1319 		 * data is in the unformatted node.
1320 		 *
1321 		 * Otherwise, we would have to call
1322 		 * reiserfs_prepare_for_journal on the unformatted node,
1323 		 * which might schedule, meaning we'd have to loop all the
1324 		 * way back up to the start of the while loop.
1325 		 *
1326 		 * The unformatted node must be dirtied later on.  We can't be
1327 		 * sure here if the entire tail has been deleted yet.
1328 		 *
1329 		 * un_bh is from the page cache (all unformatted nodes are
1330 		 * from the page cache) and might be a highmem page.  So, we
1331 		 * can't use un_bh->b_data.
1332 		 * -clm
1333 		 */
1334 
1335 		data = kmap_atomic(un_bh->b_page);
1336 		off = ((le_ih_k_offset(&s_ih) - 1) & (PAGE_SIZE - 1));
1337 		memcpy(data + off,
1338 		       ih_item_body(PATH_PLAST_BUFFER(path), &s_ih),
1339 		       ret_value);
1340 		kunmap_atomic(data);
1341 	}
1342 
1343 	/* Perform balancing after all resources have been collected at once. */
1344 	do_balance(&s_del_balance, NULL, NULL, M_DELETE);
1345 
1346 #ifdef REISERQUOTA_DEBUG
1347 	reiserfs_debug(sb, REISERFS_DEBUG_CODE,
1348 		       "reiserquota delete_item(): freeing %u, id=%u type=%c",
1349 		       quota_cut_bytes, inode->i_uid, head2type(&s_ih));
1350 #endif
1351 	depth = reiserfs_write_unlock_nested(inode->i_sb);
1352 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1353 	reiserfs_write_lock_nested(inode->i_sb, depth);
1354 
1355 	/* Return deleted body length */
1356 	return ret_value;
1357 }
1358 
1359 /*
1360  * Summary Of Mechanisms For Handling Collisions Between Processes:
1361  *
1362  *  deletion of the body of the object is performed by iput(), with the
1363  *  result that if multiple processes are operating on a file, the
1364  *  deletion of the body of the file is deferred until the last process
1365  *  that has an open inode performs its iput().
1366  *
1367  *  writes and truncates are protected from collisions by use of
1368  *  semaphores.
1369  *
1370  *  creates, linking, and mknod are protected from collisions with other
1371  *  processes by making the reiserfs_add_entry() the last step in the
1372  *  creation, and then rolling back all changes if there was a collision.
1373  *  - Hans
1374 */
1375 
1376 /* this deletes item which never gets split */
1377 void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
1378 				struct inode *inode, struct reiserfs_key *key)
1379 {
1380 	struct super_block *sb = th->t_super;
1381 	struct tree_balance tb;
1382 	INITIALIZE_PATH(path);
1383 	int item_len = 0;
1384 	int tb_init = 0;
1385 	struct cpu_key cpu_key;
1386 	int retval;
1387 	int quota_cut_bytes = 0;
1388 
1389 	BUG_ON(!th->t_trans_id);
1390 
1391 	le_key2cpu_key(&cpu_key, key);
1392 
1393 	while (1) {
1394 		retval = search_item(th->t_super, &cpu_key, &path);
1395 		if (retval == IO_ERROR) {
1396 			reiserfs_error(th->t_super, "vs-5350",
1397 				       "i/o failure occurred trying "
1398 				       "to delete %K", &cpu_key);
1399 			break;
1400 		}
1401 		if (retval != ITEM_FOUND) {
1402 			pathrelse(&path);
1403 			/*
1404 			 * No need for a warning, if there is just no free
1405 			 * space to insert '..' item into the
1406 			 * newly-created subdir
1407 			 */
1408 			if (!
1409 			    ((unsigned long long)
1410 			     GET_HASH_VALUE(le_key_k_offset
1411 					    (le_key_version(key), key)) == 0
1412 			     && (unsigned long long)
1413 			     GET_GENERATION_NUMBER(le_key_k_offset
1414 						   (le_key_version(key),
1415 						    key)) == 1))
1416 				reiserfs_warning(th->t_super, "vs-5355",
1417 						 "%k not found", key);
1418 			break;
1419 		}
1420 		if (!tb_init) {
1421 			tb_init = 1;
1422 			item_len = ih_item_len(tp_item_head(&path));
1423 			init_tb_struct(th, &tb, th->t_super, &path,
1424 				       -(IH_SIZE + item_len));
1425 		}
1426 		quota_cut_bytes = ih_item_len(tp_item_head(&path));
1427 
1428 		retval = fix_nodes(M_DELETE, &tb, NULL, NULL);
1429 		if (retval == REPEAT_SEARCH) {
1430 			PROC_INFO_INC(th->t_super, delete_solid_item_restarted);
1431 			continue;
1432 		}
1433 
1434 		if (retval == CARRY_ON) {
1435 			do_balance(&tb, NULL, NULL, M_DELETE);
1436 			/*
1437 			 * Should we count quota for item? (we don't
1438 			 * count quotas for save-links)
1439 			 */
1440 			if (inode) {
1441 				int depth;
1442 #ifdef REISERQUOTA_DEBUG
1443 				reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
1444 					       "reiserquota delete_solid_item(): freeing %u id=%u type=%c",
1445 					       quota_cut_bytes, inode->i_uid,
1446 					       key2type(key));
1447 #endif
1448 				depth = reiserfs_write_unlock_nested(sb);
1449 				dquot_free_space_nodirty(inode,
1450 							 quota_cut_bytes);
1451 				reiserfs_write_lock_nested(sb, depth);
1452 			}
1453 			break;
1454 		}
1455 
1456 		/* IO_ERROR, NO_DISK_SPACE, etc */
1457 		reiserfs_warning(th->t_super, "vs-5360",
1458 				 "could not delete %K due to fix_nodes failure",
1459 				 &cpu_key);
1460 		unfix_nodes(&tb);
1461 		break;
1462 	}
1463 
1464 	reiserfs_check_path(&path);
1465 }
1466 
1467 int reiserfs_delete_object(struct reiserfs_transaction_handle *th,
1468 			   struct inode *inode)
1469 {
1470 	int err;
1471 	inode->i_size = 0;
1472 	BUG_ON(!th->t_trans_id);
1473 
1474 	/* for directory this deletes item containing "." and ".." */
1475 	err =
1476 	    reiserfs_do_truncate(th, inode, NULL, 0 /*no timestamp updates */ );
1477 	if (err)
1478 		return err;
1479 
1480 #if defined( USE_INODE_GENERATION_COUNTER )
1481 	if (!old_format_only(th->t_super)) {
1482 		__le32 *inode_generation;
1483 
1484 		inode_generation =
1485 		    &REISERFS_SB(th->t_super)->s_rs->s_inode_generation;
1486 		le32_add_cpu(inode_generation, 1);
1487 	}
1488 /* USE_INODE_GENERATION_COUNTER */
1489 #endif
1490 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1491 
1492 	return err;
1493 }
1494 
1495 static void unmap_buffers(struct page *page, loff_t pos)
1496 {
1497 	struct buffer_head *bh;
1498 	struct buffer_head *head;
1499 	struct buffer_head *next;
1500 	unsigned long tail_index;
1501 	unsigned long cur_index;
1502 
1503 	if (page) {
1504 		if (page_has_buffers(page)) {
1505 			tail_index = pos & (PAGE_SIZE - 1);
1506 			cur_index = 0;
1507 			head = page_buffers(page);
1508 			bh = head;
1509 			do {
1510 				next = bh->b_this_page;
1511 
1512 				/*
1513 				 * we want to unmap the buffers that contain
1514 				 * the tail, and all the buffers after it
1515 				 * (since the tail must be at the end of the
1516 				 * file).  We don't want to unmap file data
1517 				 * before the tail, since it might be dirty
1518 				 * and waiting to reach disk
1519 				 */
1520 				cur_index += bh->b_size;
1521 				if (cur_index > tail_index) {
1522 					reiserfs_unmap_buffer(bh);
1523 				}
1524 				bh = next;
1525 			} while (bh != head);
1526 		}
1527 	}
1528 }
1529 
1530 static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
1531 				    struct inode *inode,
1532 				    struct page *page,
1533 				    struct treepath *path,
1534 				    const struct cpu_key *item_key,
1535 				    loff_t new_file_size, char *mode)
1536 {
1537 	struct super_block *sb = inode->i_sb;
1538 	int block_size = sb->s_blocksize;
1539 	int cut_bytes;
1540 	BUG_ON(!th->t_trans_id);
1541 	BUG_ON(new_file_size != inode->i_size);
1542 
1543 	/*
1544 	 * the page being sent in could be NULL if there was an i/o error
1545 	 * reading in the last block.  The user will hit problems trying to
1546 	 * read the file, but for now we just skip the indirect2direct
1547 	 */
1548 	if (atomic_read(&inode->i_count) > 1 ||
1549 	    !tail_has_to_be_packed(inode) ||
1550 	    !page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
1551 		/* leave tail in an unformatted node */
1552 		*mode = M_SKIP_BALANCING;
1553 		cut_bytes =
1554 		    block_size - (new_file_size & (block_size - 1));
1555 		pathrelse(path);
1556 		return cut_bytes;
1557 	}
1558 
1559 	/* Perform the conversion to a direct_item. */
1560 	return indirect2direct(th, inode, page, path, item_key,
1561 			       new_file_size, mode);
1562 }
1563 
1564 /*
1565  * we did indirect_to_direct conversion. And we have inserted direct
1566  * item successesfully, but there were no disk space to cut unfm
1567  * pointer being converted. Therefore we have to delete inserted
1568  * direct item(s)
1569  */
1570 static void indirect_to_direct_roll_back(struct reiserfs_transaction_handle *th,
1571 					 struct inode *inode, struct treepath *path)
1572 {
1573 	struct cpu_key tail_key;
1574 	int tail_len;
1575 	int removed;
1576 	BUG_ON(!th->t_trans_id);
1577 
1578 	make_cpu_key(&tail_key, inode, inode->i_size + 1, TYPE_DIRECT, 4);
1579 	tail_key.key_length = 4;
1580 
1581 	tail_len =
1582 	    (cpu_key_k_offset(&tail_key) & (inode->i_sb->s_blocksize - 1)) - 1;
1583 	while (tail_len) {
1584 		/* look for the last byte of the tail */
1585 		if (search_for_position_by_key(inode->i_sb, &tail_key, path) ==
1586 		    POSITION_NOT_FOUND)
1587 			reiserfs_panic(inode->i_sb, "vs-5615",
1588 				       "found invalid item");
1589 		RFALSE(path->pos_in_item !=
1590 		       ih_item_len(tp_item_head(path)) - 1,
1591 		       "vs-5616: appended bytes found");
1592 		PATH_LAST_POSITION(path)--;
1593 
1594 		removed =
1595 		    reiserfs_delete_item(th, path, &tail_key, inode,
1596 					 NULL /*unbh not needed */ );
1597 		RFALSE(removed <= 0
1598 		       || removed > tail_len,
1599 		       "vs-5617: there was tail %d bytes, removed item length %d bytes",
1600 		       tail_len, removed);
1601 		tail_len -= removed;
1602 		set_cpu_key_k_offset(&tail_key,
1603 				     cpu_key_k_offset(&tail_key) - removed);
1604 	}
1605 	reiserfs_warning(inode->i_sb, "reiserfs-5091", "indirect_to_direct "
1606 			 "conversion has been rolled back due to "
1607 			 "lack of disk space");
1608 	mark_inode_dirty(inode);
1609 }
1610 
1611 /* (Truncate or cut entry) or delete object item. Returns < 0 on failure */
1612 int reiserfs_cut_from_item(struct reiserfs_transaction_handle *th,
1613 			   struct treepath *path,
1614 			   struct cpu_key *item_key,
1615 			   struct inode *inode,
1616 			   struct page *page, loff_t new_file_size)
1617 {
1618 	struct super_block *sb = inode->i_sb;
1619 	/*
1620 	 * Every function which is going to call do_balance must first
1621 	 * create a tree_balance structure.  Then it must fill up this
1622 	 * structure by using the init_tb_struct and fix_nodes functions.
1623 	 * After that we can make tree balancing.
1624 	 */
1625 	struct tree_balance s_cut_balance;
1626 	struct item_head *p_le_ih;
1627 	int cut_size = 0;	/* Amount to be cut. */
1628 	int ret_value = CARRY_ON;
1629 	int removed = 0;	/* Number of the removed unformatted nodes. */
1630 	int is_inode_locked = 0;
1631 	char mode;		/* Mode of the balance. */
1632 	int retval2 = -1;
1633 	int quota_cut_bytes;
1634 	loff_t tail_pos = 0;
1635 	int depth;
1636 
1637 	BUG_ON(!th->t_trans_id);
1638 
1639 	init_tb_struct(th, &s_cut_balance, inode->i_sb, path,
1640 		       cut_size);
1641 
1642 	/*
1643 	 * Repeat this loop until we either cut the item without needing
1644 	 * to balance, or we fix_nodes without schedule occurring
1645 	 */
1646 	while (1) {
1647 		/*
1648 		 * Determine the balance mode, position of the first byte to
1649 		 * be cut, and size to be cut.  In case of the indirect item
1650 		 * free unformatted nodes which are pointed to by the cut
1651 		 * pointers.
1652 		 */
1653 
1654 		mode =
1655 		    prepare_for_delete_or_cut(th, inode, path,
1656 					      item_key, &removed,
1657 					      &cut_size, new_file_size);
1658 		if (mode == M_CONVERT) {
1659 			/*
1660 			 * convert last unformatted node to direct item or
1661 			 * leave tail in the unformatted node
1662 			 */
1663 			RFALSE(ret_value != CARRY_ON,
1664 			       "PAP-5570: can not convert twice");
1665 
1666 			ret_value =
1667 			    maybe_indirect_to_direct(th, inode, page,
1668 						     path, item_key,
1669 						     new_file_size, &mode);
1670 			if (mode == M_SKIP_BALANCING)
1671 				/* tail has been left in the unformatted node */
1672 				return ret_value;
1673 
1674 			is_inode_locked = 1;
1675 
1676 			/*
1677 			 * removing of last unformatted node will
1678 			 * change value we have to return to truncate.
1679 			 * Save it
1680 			 */
1681 			retval2 = ret_value;
1682 
1683 			/*
1684 			 * So, we have performed the first part of the
1685 			 * conversion:
1686 			 * inserting the new direct item.  Now we are
1687 			 * removing the last unformatted node pointer.
1688 			 * Set key to search for it.
1689 			 */
1690 			set_cpu_key_k_type(item_key, TYPE_INDIRECT);
1691 			item_key->key_length = 4;
1692 			new_file_size -=
1693 			    (new_file_size & (sb->s_blocksize - 1));
1694 			tail_pos = new_file_size;
1695 			set_cpu_key_k_offset(item_key, new_file_size + 1);
1696 			if (search_for_position_by_key
1697 			    (sb, item_key,
1698 			     path) == POSITION_NOT_FOUND) {
1699 				print_block(PATH_PLAST_BUFFER(path), 3,
1700 					    PATH_LAST_POSITION(path) - 1,
1701 					    PATH_LAST_POSITION(path) + 1);
1702 				reiserfs_panic(sb, "PAP-5580", "item to "
1703 					       "convert does not exist (%K)",
1704 					       item_key);
1705 			}
1706 			continue;
1707 		}
1708 		if (cut_size == 0) {
1709 			pathrelse(path);
1710 			return 0;
1711 		}
1712 
1713 		s_cut_balance.insert_size[0] = cut_size;
1714 
1715 		ret_value = fix_nodes(mode, &s_cut_balance, NULL, NULL);
1716 		if (ret_value != REPEAT_SEARCH)
1717 			break;
1718 
1719 		PROC_INFO_INC(sb, cut_from_item_restarted);
1720 
1721 		ret_value =
1722 		    search_for_position_by_key(sb, item_key, path);
1723 		if (ret_value == POSITION_FOUND)
1724 			continue;
1725 
1726 		reiserfs_warning(sb, "PAP-5610", "item %K not found",
1727 				 item_key);
1728 		unfix_nodes(&s_cut_balance);
1729 		return (ret_value == IO_ERROR) ? -EIO : -ENOENT;
1730 	}			/* while */
1731 
1732 	/* check fix_nodes results (IO_ERROR or NO_DISK_SPACE) */
1733 	if (ret_value != CARRY_ON) {
1734 		if (is_inode_locked) {
1735 			/*
1736 			 * FIXME: this seems to be not needed: we are always
1737 			 * able to cut item
1738 			 */
1739 			indirect_to_direct_roll_back(th, inode, path);
1740 		}
1741 		if (ret_value == NO_DISK_SPACE)
1742 			reiserfs_warning(sb, "reiserfs-5092",
1743 					 "NO_DISK_SPACE");
1744 		unfix_nodes(&s_cut_balance);
1745 		return -EIO;
1746 	}
1747 
1748 	/* go ahead and perform balancing */
1749 
1750 	RFALSE(mode == M_PASTE || mode == M_INSERT, "invalid mode");
1751 
1752 	/* Calculate number of bytes that need to be cut from the item. */
1753 	quota_cut_bytes =
1754 	    (mode ==
1755 	     M_DELETE) ? ih_item_len(tp_item_head(path)) : -s_cut_balance.
1756 	    insert_size[0];
1757 	if (retval2 == -1)
1758 		ret_value = calc_deleted_bytes_number(&s_cut_balance, mode);
1759 	else
1760 		ret_value = retval2;
1761 
1762 	/*
1763 	 * For direct items, we only change the quota when deleting the last
1764 	 * item.
1765 	 */
1766 	p_le_ih = tp_item_head(s_cut_balance.tb_path);
1767 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(p_le_ih)) {
1768 		if (mode == M_DELETE &&
1769 		    (le_ih_k_offset(p_le_ih) & (sb->s_blocksize - 1)) ==
1770 		    1) {
1771 			/* FIXME: this is to keep 3.5 happy */
1772 			REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
1773 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1774 		} else {
1775 			quota_cut_bytes = 0;
1776 		}
1777 	}
1778 #ifdef CONFIG_REISERFS_CHECK
1779 	if (is_inode_locked) {
1780 		struct item_head *le_ih =
1781 		    tp_item_head(s_cut_balance.tb_path);
1782 		/*
1783 		 * we are going to complete indirect2direct conversion. Make
1784 		 * sure, that we exactly remove last unformatted node pointer
1785 		 * of the item
1786 		 */
1787 		if (!is_indirect_le_ih(le_ih))
1788 			reiserfs_panic(sb, "vs-5652",
1789 				       "item must be indirect %h", le_ih);
1790 
1791 		if (mode == M_DELETE && ih_item_len(le_ih) != UNFM_P_SIZE)
1792 			reiserfs_panic(sb, "vs-5653", "completing "
1793 				       "indirect2direct conversion indirect "
1794 				       "item %h being deleted must be of "
1795 				       "4 byte long", le_ih);
1796 
1797 		if (mode == M_CUT
1798 		    && s_cut_balance.insert_size[0] != -UNFM_P_SIZE) {
1799 			reiserfs_panic(sb, "vs-5654", "can not complete "
1800 				       "indirect2direct conversion of %h "
1801 				       "(CUT, insert_size==%d)",
1802 				       le_ih, s_cut_balance.insert_size[0]);
1803 		}
1804 		/*
1805 		 * it would be useful to make sure, that right neighboring
1806 		 * item is direct item of this file
1807 		 */
1808 	}
1809 #endif
1810 
1811 	do_balance(&s_cut_balance, NULL, NULL, mode);
1812 	if (is_inode_locked) {
1813 		/*
1814 		 * we've done an indirect->direct conversion.  when the
1815 		 * data block was freed, it was removed from the list of
1816 		 * blocks that must be flushed before the transaction
1817 		 * commits, make sure to unmap and invalidate it
1818 		 */
1819 		unmap_buffers(page, tail_pos);
1820 		REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
1821 	}
1822 #ifdef REISERQUOTA_DEBUG
1823 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
1824 		       "reiserquota cut_from_item(): freeing %u id=%u type=%c",
1825 		       quota_cut_bytes, inode->i_uid, '?');
1826 #endif
1827 	depth = reiserfs_write_unlock_nested(sb);
1828 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1829 	reiserfs_write_lock_nested(sb, depth);
1830 	return ret_value;
1831 }
1832 
1833 static void truncate_directory(struct reiserfs_transaction_handle *th,
1834 			       struct inode *inode)
1835 {
1836 	BUG_ON(!th->t_trans_id);
1837 	if (inode->i_nlink)
1838 		reiserfs_error(inode->i_sb, "vs-5655", "link count != 0");
1839 
1840 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), DOT_OFFSET);
1841 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_DIRENTRY);
1842 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1843 	reiserfs_update_sd(th, inode);
1844 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), SD_OFFSET);
1845 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_STAT_DATA);
1846 }
1847 
1848 /*
1849  * Truncate file to the new size. Note, this must be called with a
1850  * transaction already started
1851  */
1852 int reiserfs_do_truncate(struct reiserfs_transaction_handle *th,
1853 			 struct inode *inode,	/* ->i_size contains new size */
1854 			 struct page *page,	/* up to date for last block */
1855 			 /*
1856 			  * when it is called by file_release to convert
1857 			  * the tail - no timestamps should be updated
1858 			  */
1859 			 int update_timestamps
1860     )
1861 {
1862 	INITIALIZE_PATH(s_search_path);	/* Path to the current object item. */
1863 	struct item_head *p_le_ih;	/* Pointer to an item header. */
1864 
1865 	/* Key to search for a previous file item. */
1866 	struct cpu_key s_item_key;
1867 	loff_t file_size,	/* Old file size. */
1868 	 new_file_size;	/* New file size. */
1869 	int deleted;		/* Number of deleted or truncated bytes. */
1870 	int retval;
1871 	int err = 0;
1872 
1873 	BUG_ON(!th->t_trans_id);
1874 	if (!
1875 	    (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
1876 	     || S_ISLNK(inode->i_mode)))
1877 		return 0;
1878 
1879 	/* deletion of directory - no need to update timestamps */
1880 	if (S_ISDIR(inode->i_mode)) {
1881 		truncate_directory(th, inode);
1882 		return 0;
1883 	}
1884 
1885 	/* Get new file size. */
1886 	new_file_size = inode->i_size;
1887 
1888 	/* FIXME: note, that key type is unimportant here */
1889 	make_cpu_key(&s_item_key, inode, max_reiserfs_offset(inode),
1890 		     TYPE_DIRECT, 3);
1891 
1892 	retval =
1893 	    search_for_position_by_key(inode->i_sb, &s_item_key,
1894 				       &s_search_path);
1895 	if (retval == IO_ERROR) {
1896 		reiserfs_error(inode->i_sb, "vs-5657",
1897 			       "i/o failure occurred trying to truncate %K",
1898 			       &s_item_key);
1899 		err = -EIO;
1900 		goto out;
1901 	}
1902 	if (retval == POSITION_FOUND || retval == FILE_NOT_FOUND) {
1903 		reiserfs_error(inode->i_sb, "PAP-5660",
1904 			       "wrong result %d of search for %K", retval,
1905 			       &s_item_key);
1906 
1907 		err = -EIO;
1908 		goto out;
1909 	}
1910 
1911 	s_search_path.pos_in_item--;
1912 
1913 	/* Get real file size (total length of all file items) */
1914 	p_le_ih = tp_item_head(&s_search_path);
1915 	if (is_statdata_le_ih(p_le_ih))
1916 		file_size = 0;
1917 	else {
1918 		loff_t offset = le_ih_k_offset(p_le_ih);
1919 		int bytes =
1920 		    op_bytes_number(p_le_ih, inode->i_sb->s_blocksize);
1921 
1922 		/*
1923 		 * this may mismatch with real file size: if last direct item
1924 		 * had no padding zeros and last unformatted node had no free
1925 		 * space, this file would have this file size
1926 		 */
1927 		file_size = offset + bytes - 1;
1928 	}
1929 	/*
1930 	 * are we doing a full truncate or delete, if so
1931 	 * kick in the reada code
1932 	 */
1933 	if (new_file_size == 0)
1934 		s_search_path.reada = PATH_READA | PATH_READA_BACK;
1935 
1936 	if (file_size == 0 || file_size < new_file_size) {
1937 		goto update_and_out;
1938 	}
1939 
1940 	/* Update key to search for the last file item. */
1941 	set_cpu_key_k_offset(&s_item_key, file_size);
1942 
1943 	do {
1944 		/* Cut or delete file item. */
1945 		deleted =
1946 		    reiserfs_cut_from_item(th, &s_search_path, &s_item_key,
1947 					   inode, page, new_file_size);
1948 		if (deleted < 0) {
1949 			reiserfs_warning(inode->i_sb, "vs-5665",
1950 					 "reiserfs_cut_from_item failed");
1951 			reiserfs_check_path(&s_search_path);
1952 			return 0;
1953 		}
1954 
1955 		RFALSE(deleted > file_size,
1956 		       "PAP-5670: reiserfs_cut_from_item: too many bytes deleted: deleted %d, file_size %lu, item_key %K",
1957 		       deleted, file_size, &s_item_key);
1958 
1959 		/* Change key to search the last file item. */
1960 		file_size -= deleted;
1961 
1962 		set_cpu_key_k_offset(&s_item_key, file_size);
1963 
1964 		/*
1965 		 * While there are bytes to truncate and previous
1966 		 * file item is presented in the tree.
1967 		 */
1968 
1969 		/*
1970 		 * This loop could take a really long time, and could log
1971 		 * many more blocks than a transaction can hold.  So, we do
1972 		 * a polite journal end here, and if the transaction needs
1973 		 * ending, we make sure the file is consistent before ending
1974 		 * the current trans and starting a new one
1975 		 */
1976 		if (journal_transaction_should_end(th, 0) ||
1977 		    reiserfs_transaction_free_space(th) <= JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD) {
1978 			pathrelse(&s_search_path);
1979 
1980 			if (update_timestamps) {
1981 				inode->i_mtime = current_time(inode);
1982 				inode->i_ctime = current_time(inode);
1983 			}
1984 			reiserfs_update_sd(th, inode);
1985 
1986 			err = journal_end(th);
1987 			if (err)
1988 				goto out;
1989 			err = journal_begin(th, inode->i_sb,
1990 					    JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD + JOURNAL_PER_BALANCE_CNT * 4) ;
1991 			if (err)
1992 				goto out;
1993 			reiserfs_update_inode_transaction(inode);
1994 		}
1995 	} while (file_size > ROUND_UP(new_file_size) &&
1996 		 search_for_position_by_key(inode->i_sb, &s_item_key,
1997 					    &s_search_path) == POSITION_FOUND);
1998 
1999 	RFALSE(file_size > ROUND_UP(new_file_size),
2000 	       "PAP-5680: truncate did not finish: new_file_size %lld, current %lld, oid %d",
2001 	       new_file_size, file_size, s_item_key.on_disk_key.k_objectid);
2002 
2003 update_and_out:
2004 	if (update_timestamps) {
2005 		/* this is truncate, not file closing */
2006 		inode->i_mtime = current_time(inode);
2007 		inode->i_ctime = current_time(inode);
2008 	}
2009 	reiserfs_update_sd(th, inode);
2010 
2011 out:
2012 	pathrelse(&s_search_path);
2013 	return err;
2014 }
2015 
2016 #ifdef CONFIG_REISERFS_CHECK
2017 /* this makes sure, that we __append__, not overwrite or add holes */
2018 static void check_research_for_paste(struct treepath *path,
2019 				     const struct cpu_key *key)
2020 {
2021 	struct item_head *found_ih = tp_item_head(path);
2022 
2023 	if (is_direct_le_ih(found_ih)) {
2024 		if (le_ih_k_offset(found_ih) +
2025 		    op_bytes_number(found_ih,
2026 				    get_last_bh(path)->b_size) !=
2027 		    cpu_key_k_offset(key)
2028 		    || op_bytes_number(found_ih,
2029 				       get_last_bh(path)->b_size) !=
2030 		    pos_in_item(path))
2031 			reiserfs_panic(NULL, "PAP-5720", "found direct item "
2032 				       "%h or position (%d) does not match "
2033 				       "to key %K", found_ih,
2034 				       pos_in_item(path), key);
2035 	}
2036 	if (is_indirect_le_ih(found_ih)) {
2037 		if (le_ih_k_offset(found_ih) +
2038 		    op_bytes_number(found_ih,
2039 				    get_last_bh(path)->b_size) !=
2040 		    cpu_key_k_offset(key)
2041 		    || I_UNFM_NUM(found_ih) != pos_in_item(path)
2042 		    || get_ih_free_space(found_ih) != 0)
2043 			reiserfs_panic(NULL, "PAP-5730", "found indirect "
2044 				       "item (%h) or position (%d) does not "
2045 				       "match to key (%K)",
2046 				       found_ih, pos_in_item(path), key);
2047 	}
2048 }
2049 #endif				/* config reiserfs check */
2050 
2051 /*
2052  * Paste bytes to the existing item.
2053  * Returns bytes number pasted into the item.
2054  */
2055 int reiserfs_paste_into_item(struct reiserfs_transaction_handle *th,
2056 			     /* Path to the pasted item. */
2057 			     struct treepath *search_path,
2058 			     /* Key to search for the needed item. */
2059 			     const struct cpu_key *key,
2060 			     /* Inode item belongs to */
2061 			     struct inode *inode,
2062 			     /* Pointer to the bytes to paste. */
2063 			     const char *body,
2064 			     /* Size of pasted bytes. */
2065 			     int pasted_size)
2066 {
2067 	struct super_block *sb = inode->i_sb;
2068 	struct tree_balance s_paste_balance;
2069 	int retval;
2070 	int fs_gen;
2071 	int depth;
2072 
2073 	BUG_ON(!th->t_trans_id);
2074 
2075 	fs_gen = get_generation(inode->i_sb);
2076 
2077 #ifdef REISERQUOTA_DEBUG
2078 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2079 		       "reiserquota paste_into_item(): allocating %u id=%u type=%c",
2080 		       pasted_size, inode->i_uid,
2081 		       key2type(&key->on_disk_key));
2082 #endif
2083 
2084 	depth = reiserfs_write_unlock_nested(sb);
2085 	retval = dquot_alloc_space_nodirty(inode, pasted_size);
2086 	reiserfs_write_lock_nested(sb, depth);
2087 	if (retval) {
2088 		pathrelse(search_path);
2089 		return retval;
2090 	}
2091 	init_tb_struct(th, &s_paste_balance, th->t_super, search_path,
2092 		       pasted_size);
2093 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2094 	s_paste_balance.key = key->on_disk_key;
2095 #endif
2096 
2097 	/* DQUOT_* can schedule, must check before the fix_nodes */
2098 	if (fs_changed(fs_gen, inode->i_sb)) {
2099 		goto search_again;
2100 	}
2101 
2102 	while ((retval =
2103 		fix_nodes(M_PASTE, &s_paste_balance, NULL,
2104 			  body)) == REPEAT_SEARCH) {
2105 search_again:
2106 		/* file system changed while we were in the fix_nodes */
2107 		PROC_INFO_INC(th->t_super, paste_into_item_restarted);
2108 		retval =
2109 		    search_for_position_by_key(th->t_super, key,
2110 					       search_path);
2111 		if (retval == IO_ERROR) {
2112 			retval = -EIO;
2113 			goto error_out;
2114 		}
2115 		if (retval == POSITION_FOUND) {
2116 			reiserfs_warning(inode->i_sb, "PAP-5710",
2117 					 "entry or pasted byte (%K) exists",
2118 					 key);
2119 			retval = -EEXIST;
2120 			goto error_out;
2121 		}
2122 #ifdef CONFIG_REISERFS_CHECK
2123 		check_research_for_paste(search_path, key);
2124 #endif
2125 	}
2126 
2127 	/*
2128 	 * Perform balancing after all resources are collected by fix_nodes,
2129 	 * and accessing them will not risk triggering schedule.
2130 	 */
2131 	if (retval == CARRY_ON) {
2132 		do_balance(&s_paste_balance, NULL /*ih */ , body, M_PASTE);
2133 		return 0;
2134 	}
2135 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2136 error_out:
2137 	/* this also releases the path */
2138 	unfix_nodes(&s_paste_balance);
2139 #ifdef REISERQUOTA_DEBUG
2140 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2141 		       "reiserquota paste_into_item(): freeing %u id=%u type=%c",
2142 		       pasted_size, inode->i_uid,
2143 		       key2type(&key->on_disk_key));
2144 #endif
2145 	depth = reiserfs_write_unlock_nested(sb);
2146 	dquot_free_space_nodirty(inode, pasted_size);
2147 	reiserfs_write_lock_nested(sb, depth);
2148 	return retval;
2149 }
2150 
2151 /*
2152  * Insert new item into the buffer at the path.
2153  * th   - active transaction handle
2154  * path - path to the inserted item
2155  * ih   - pointer to the item header to insert
2156  * body - pointer to the bytes to insert
2157  */
2158 int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
2159 			 struct treepath *path, const struct cpu_key *key,
2160 			 struct item_head *ih, struct inode *inode,
2161 			 const char *body)
2162 {
2163 	struct tree_balance s_ins_balance;
2164 	int retval;
2165 	int fs_gen = 0;
2166 	int quota_bytes = 0;
2167 
2168 	BUG_ON(!th->t_trans_id);
2169 
2170 	if (inode) {		/* Do we count quotas for item? */
2171 		int depth;
2172 		fs_gen = get_generation(inode->i_sb);
2173 		quota_bytes = ih_item_len(ih);
2174 
2175 		/*
2176 		 * hack so the quota code doesn't have to guess
2177 		 * if the file has a tail, links are always tails,
2178 		 * so there's no guessing needed
2179 		 */
2180 		if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(ih))
2181 			quota_bytes = inode->i_sb->s_blocksize + UNFM_P_SIZE;
2182 #ifdef REISERQUOTA_DEBUG
2183 		reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2184 			       "reiserquota insert_item(): allocating %u id=%u type=%c",
2185 			       quota_bytes, inode->i_uid, head2type(ih));
2186 #endif
2187 		/*
2188 		 * We can't dirty inode here. It would be immediately
2189 		 * written but appropriate stat item isn't inserted yet...
2190 		 */
2191 		depth = reiserfs_write_unlock_nested(inode->i_sb);
2192 		retval = dquot_alloc_space_nodirty(inode, quota_bytes);
2193 		reiserfs_write_lock_nested(inode->i_sb, depth);
2194 		if (retval) {
2195 			pathrelse(path);
2196 			return retval;
2197 		}
2198 	}
2199 	init_tb_struct(th, &s_ins_balance, th->t_super, path,
2200 		       IH_SIZE + ih_item_len(ih));
2201 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2202 	s_ins_balance.key = key->on_disk_key;
2203 #endif
2204 	/*
2205 	 * DQUOT_* can schedule, must check to be sure calling
2206 	 * fix_nodes is safe
2207 	 */
2208 	if (inode && fs_changed(fs_gen, inode->i_sb)) {
2209 		goto search_again;
2210 	}
2211 
2212 	while ((retval =
2213 		fix_nodes(M_INSERT, &s_ins_balance, ih,
2214 			  body)) == REPEAT_SEARCH) {
2215 search_again:
2216 		/* file system changed while we were in the fix_nodes */
2217 		PROC_INFO_INC(th->t_super, insert_item_restarted);
2218 		retval = search_item(th->t_super, key, path);
2219 		if (retval == IO_ERROR) {
2220 			retval = -EIO;
2221 			goto error_out;
2222 		}
2223 		if (retval == ITEM_FOUND) {
2224 			reiserfs_warning(th->t_super, "PAP-5760",
2225 					 "key %K already exists in the tree",
2226 					 key);
2227 			retval = -EEXIST;
2228 			goto error_out;
2229 		}
2230 	}
2231 
2232 	/* make balancing after all resources will be collected at a time */
2233 	if (retval == CARRY_ON) {
2234 		do_balance(&s_ins_balance, ih, body, M_INSERT);
2235 		return 0;
2236 	}
2237 
2238 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2239 error_out:
2240 	/* also releases the path */
2241 	unfix_nodes(&s_ins_balance);
2242 #ifdef REISERQUOTA_DEBUG
2243 	if (inode)
2244 		reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
2245 		       "reiserquota insert_item(): freeing %u id=%u type=%c",
2246 		       quota_bytes, inode->i_uid, head2type(ih));
2247 #endif
2248 	if (inode) {
2249 		int depth = reiserfs_write_unlock_nested(inode->i_sb);
2250 		dquot_free_space_nodirty(inode, quota_bytes);
2251 		reiserfs_write_lock_nested(inode->i_sb, depth);
2252 	}
2253 	return retval;
2254 }
2255