xref: /openbmc/linux/fs/reiserfs/stree.c (revision d9fd5a71)
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 		if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) {
458 			reiserfs_warning(NULL, "reiserfs-5093",
459 					 "item entry count seems wrong %h",
460 					 ih);
461 			return 0;
462 		}
463 		prev_location = ih_location(ih);
464 	}
465 
466 	/* one may imagine many more checks */
467 	return 1;
468 }
469 
470 /* returns 1 if buf looks like an internal node, 0 otherwise */
471 static int is_internal(char *buf, int blocksize, struct buffer_head *bh)
472 {
473 	struct block_head *blkh;
474 	int nr;
475 	int used_space;
476 
477 	blkh = (struct block_head *)buf;
478 	nr = blkh_level(blkh);
479 	if (nr <= DISK_LEAF_NODE_LEVEL || nr > MAX_HEIGHT) {
480 		/* this level is not possible for internal nodes */
481 		reiserfs_warning(NULL, "reiserfs-5087",
482 				 "this should be caught earlier");
483 		return 0;
484 	}
485 
486 	nr = blkh_nr_item(blkh);
487 	/* for internal which is not root we might check min number of keys */
488 	if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
489 		reiserfs_warning(NULL, "reiserfs-5088",
490 				 "number of key seems wrong: %z", bh);
491 		return 0;
492 	}
493 
494 	used_space = BLKH_SIZE + KEY_SIZE * nr + DC_SIZE * (nr + 1);
495 	if (used_space != blocksize - blkh_free_space(blkh)) {
496 		reiserfs_warning(NULL, "reiserfs-5089",
497 				 "free space seems wrong: %z", bh);
498 		return 0;
499 	}
500 
501 	/* one may imagine many more checks */
502 	return 1;
503 }
504 
505 /*
506  * make sure that bh contains formatted node of reiserfs tree of
507  * 'level'-th level
508  */
509 static int is_tree_node(struct buffer_head *bh, int level)
510 {
511 	if (B_LEVEL(bh) != level) {
512 		reiserfs_warning(NULL, "reiserfs-5090", "node level %d does "
513 				 "not match to the expected one %d",
514 				 B_LEVEL(bh), level);
515 		return 0;
516 	}
517 	if (level == DISK_LEAF_NODE_LEVEL)
518 		return is_leaf(bh->b_data, bh->b_size, bh);
519 
520 	return is_internal(bh->b_data, bh->b_size, bh);
521 }
522 
523 #define SEARCH_BY_KEY_READA 16
524 
525 /*
526  * The function is NOT SCHEDULE-SAFE!
527  * It might unlock the write lock if we needed to wait for a block
528  * to be read. Note that in this case it won't recover the lock to avoid
529  * high contention resulting from too much lock requests, especially
530  * the caller (search_by_key) will perform other schedule-unsafe
531  * operations just after calling this function.
532  *
533  * @return depth of lock to be restored after read completes
534  */
535 static int search_by_key_reada(struct super_block *s,
536 				struct buffer_head **bh,
537 				b_blocknr_t *b, int num)
538 {
539 	int i, j;
540 	int depth = -1;
541 
542 	for (i = 0; i < num; i++) {
543 		bh[i] = sb_getblk(s, b[i]);
544 	}
545 	/*
546 	 * We are going to read some blocks on which we
547 	 * have a reference. It's safe, though we might be
548 	 * reading blocks concurrently changed if we release
549 	 * the lock. But it's still fine because we check later
550 	 * if the tree changed
551 	 */
552 	for (j = 0; j < i; j++) {
553 		/*
554 		 * note, this needs attention if we are getting rid of the BKL
555 		 * you have to make sure the prepared bit isn't set on this
556 		 * buffer
557 		 */
558 		if (!buffer_uptodate(bh[j])) {
559 			if (depth == -1)
560 				depth = reiserfs_write_unlock_nested(s);
561 			ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, bh + j);
562 		}
563 		brelse(bh[j]);
564 	}
565 	return depth;
566 }
567 
568 /*
569  * This function fills up the path from the root to the leaf as it
570  * descends the tree looking for the key.  It uses reiserfs_bread to
571  * try to find buffers in the cache given their block number.  If it
572  * does not find them in the cache it reads them from disk.  For each
573  * node search_by_key finds using reiserfs_bread it then uses
574  * bin_search to look through that node.  bin_search will find the
575  * position of the block_number of the next node if it is looking
576  * through an internal node.  If it is looking through a leaf node
577  * bin_search will find the position of the item which has key either
578  * equal to given key, or which is the maximal key less than the given
579  * key.  search_by_key returns a path that must be checked for the
580  * correctness of the top of the path but need not be checked for the
581  * correctness of the bottom of the path
582  */
583 /*
584  * search_by_key - search for key (and item) in stree
585  * @sb: superblock
586  * @key: pointer to key to search for
587  * @search_path: Allocated and initialized struct treepath; Returned filled
588  *		 on success.
589  * @stop_level: How far down the tree to search, Use DISK_LEAF_NODE_LEVEL to
590  *		stop at leaf level.
591  *
592  * The function is NOT SCHEDULE-SAFE!
593  */
594 int search_by_key(struct super_block *sb, const struct cpu_key *key,
595 		  struct treepath *search_path, int stop_level)
596 {
597 	b_blocknr_t block_number;
598 	int expected_level;
599 	struct buffer_head *bh;
600 	struct path_element *last_element;
601 	int node_level, retval;
602 	int fs_gen;
603 	struct buffer_head *reada_bh[SEARCH_BY_KEY_READA];
604 	b_blocknr_t reada_blocks[SEARCH_BY_KEY_READA];
605 	int reada_count = 0;
606 
607 #ifdef CONFIG_REISERFS_CHECK
608 	int repeat_counter = 0;
609 #endif
610 
611 	PROC_INFO_INC(sb, search_by_key);
612 
613 	/*
614 	 * As we add each node to a path we increase its count.  This means
615 	 * that we must be careful to release all nodes in a path before we
616 	 * either discard the path struct or re-use the path struct, as we
617 	 * do here.
618 	 */
619 
620 	pathrelse(search_path);
621 
622 	/*
623 	 * With each iteration of this loop we search through the items in the
624 	 * current node, and calculate the next current node(next path element)
625 	 * for the next iteration of this loop..
626 	 */
627 	block_number = SB_ROOT_BLOCK(sb);
628 	expected_level = -1;
629 	while (1) {
630 
631 #ifdef CONFIG_REISERFS_CHECK
632 		if (!(++repeat_counter % 50000))
633 			reiserfs_warning(sb, "PAP-5100",
634 					 "%s: there were %d iterations of "
635 					 "while loop looking for key %K",
636 					 current->comm, repeat_counter,
637 					 key);
638 #endif
639 
640 		/* prep path to have another element added to it. */
641 		last_element =
642 		    PATH_OFFSET_PELEMENT(search_path,
643 					 ++search_path->path_length);
644 		fs_gen = get_generation(sb);
645 
646 		/*
647 		 * Read the next tree node, and set the last element
648 		 * in the path to have a pointer to it.
649 		 */
650 		if ((bh = last_element->pe_buffer =
651 		     sb_getblk(sb, block_number))) {
652 
653 			/*
654 			 * We'll need to drop the lock if we encounter any
655 			 * buffers that need to be read. If all of them are
656 			 * already up to date, we don't need to drop the lock.
657 			 */
658 			int depth = -1;
659 
660 			if (!buffer_uptodate(bh) && reada_count > 1)
661 				depth = search_by_key_reada(sb, reada_bh,
662 						    reada_blocks, reada_count);
663 
664 			if (!buffer_uptodate(bh) && depth == -1)
665 				depth = reiserfs_write_unlock_nested(sb);
666 
667 			ll_rw_block(REQ_OP_READ, 0, 1, &bh);
668 			wait_on_buffer(bh);
669 
670 			if (depth != -1)
671 				reiserfs_write_lock_nested(sb, depth);
672 			if (!buffer_uptodate(bh))
673 				goto io_error;
674 		} else {
675 io_error:
676 			search_path->path_length--;
677 			pathrelse(search_path);
678 			return IO_ERROR;
679 		}
680 		reada_count = 0;
681 		if (expected_level == -1)
682 			expected_level = SB_TREE_HEIGHT(sb);
683 		expected_level--;
684 
685 		/*
686 		 * It is possible that schedule occurred. We must check
687 		 * whether the key to search is still in the tree rooted
688 		 * from the current buffer. If not then repeat search
689 		 * from the root.
690 		 */
691 		if (fs_changed(fs_gen, sb) &&
692 		    (!B_IS_IN_TREE(bh) ||
693 		     B_LEVEL(bh) != expected_level ||
694 		     !key_in_buffer(search_path, key, sb))) {
695 			PROC_INFO_INC(sb, search_by_key_fs_changed);
696 			PROC_INFO_INC(sb, search_by_key_restarted);
697 			PROC_INFO_INC(sb,
698 				      sbk_restarted[expected_level - 1]);
699 			pathrelse(search_path);
700 
701 			/*
702 			 * Get the root block number so that we can
703 			 * repeat the search starting from the root.
704 			 */
705 			block_number = SB_ROOT_BLOCK(sb);
706 			expected_level = -1;
707 
708 			/* repeat search from the root */
709 			continue;
710 		}
711 
712 		/*
713 		 * only check that the key is in the buffer if key is not
714 		 * equal to the MAX_KEY. Latter case is only possible in
715 		 * "finish_unfinished()" processing during mount.
716 		 */
717 		RFALSE(comp_keys(&MAX_KEY, key) &&
718 		       !key_in_buffer(search_path, key, sb),
719 		       "PAP-5130: key is not in the buffer");
720 #ifdef CONFIG_REISERFS_CHECK
721 		if (REISERFS_SB(sb)->cur_tb) {
722 			print_cur_tb("5140");
723 			reiserfs_panic(sb, "PAP-5140",
724 				       "schedule occurred in do_balance!");
725 		}
726 #endif
727 
728 		/*
729 		 * make sure, that the node contents look like a node of
730 		 * certain level
731 		 */
732 		if (!is_tree_node(bh, expected_level)) {
733 			reiserfs_error(sb, "vs-5150",
734 				       "invalid format found in block %ld. "
735 				       "Fsck?", bh->b_blocknr);
736 			pathrelse(search_path);
737 			return IO_ERROR;
738 		}
739 
740 		/* ok, we have acquired next formatted node in the tree */
741 		node_level = B_LEVEL(bh);
742 
743 		PROC_INFO_BH_STAT(sb, bh, node_level - 1);
744 
745 		RFALSE(node_level < stop_level,
746 		       "vs-5152: tree level (%d) is less than stop level (%d)",
747 		       node_level, stop_level);
748 
749 		retval = bin_search(key, item_head(bh, 0),
750 				      B_NR_ITEMS(bh),
751 				      (node_level ==
752 				       DISK_LEAF_NODE_LEVEL) ? IH_SIZE :
753 				      KEY_SIZE,
754 				      &last_element->pe_position);
755 		if (node_level == stop_level) {
756 			return retval;
757 		}
758 
759 		/* we are not in the stop level */
760 		/*
761 		 * item has been found, so we choose the pointer which
762 		 * is to the right of the found one
763 		 */
764 		if (retval == ITEM_FOUND)
765 			last_element->pe_position++;
766 
767 		/*
768 		 * if item was not found we choose the position which is to
769 		 * the left of the found item. This requires no code,
770 		 * bin_search did it already.
771 		 */
772 
773 		/*
774 		 * So we have chosen a position in the current node which is
775 		 * an internal node.  Now we calculate child block number by
776 		 * position in the node.
777 		 */
778 		block_number =
779 		    B_N_CHILD_NUM(bh, last_element->pe_position);
780 
781 		/*
782 		 * if we are going to read leaf nodes, try for read
783 		 * ahead as well
784 		 */
785 		if ((search_path->reada & PATH_READA) &&
786 		    node_level == DISK_LEAF_NODE_LEVEL + 1) {
787 			int pos = last_element->pe_position;
788 			int limit = B_NR_ITEMS(bh);
789 			struct reiserfs_key *le_key;
790 
791 			if (search_path->reada & PATH_READA_BACK)
792 				limit = 0;
793 			while (reada_count < SEARCH_BY_KEY_READA) {
794 				if (pos == limit)
795 					break;
796 				reada_blocks[reada_count++] =
797 				    B_N_CHILD_NUM(bh, pos);
798 				if (search_path->reada & PATH_READA_BACK)
799 					pos--;
800 				else
801 					pos++;
802 
803 				/*
804 				 * check to make sure we're in the same object
805 				 */
806 				le_key = internal_key(bh, pos);
807 				if (le32_to_cpu(le_key->k_objectid) !=
808 				    key->on_disk_key.k_objectid) {
809 					break;
810 				}
811 			}
812 		}
813 	}
814 }
815 
816 /*
817  * Form the path to an item and position in this item which contains
818  * file byte defined by key. If there is no such item
819  * corresponding to the key, we point the path to the item with
820  * maximal key less than key, and *pos_in_item is set to one
821  * past the last entry/byte in the item.  If searching for entry in a
822  * directory item, and it is not found, *pos_in_item is set to one
823  * entry more than the entry with maximal key which is less than the
824  * sought key.
825  *
826  * Note that if there is no entry in this same node which is one more,
827  * then we point to an imaginary entry.  for direct items, the
828  * position is in units of bytes, for indirect items the position is
829  * in units of blocknr entries, for directory items the position is in
830  * units of directory entries.
831  */
832 /* The function is NOT SCHEDULE-SAFE! */
833 int search_for_position_by_key(struct super_block *sb,
834 			       /* Key to search (cpu variable) */
835 			       const struct cpu_key *p_cpu_key,
836 			       /* Filled up by this function. */
837 			       struct treepath *search_path)
838 {
839 	struct item_head *p_le_ih;	/* pointer to on-disk structure */
840 	int blk_size;
841 	loff_t item_offset, offset;
842 	struct reiserfs_dir_entry de;
843 	int retval;
844 
845 	/* If searching for directory entry. */
846 	if (is_direntry_cpu_key(p_cpu_key))
847 		return search_by_entry_key(sb, p_cpu_key, search_path,
848 					   &de);
849 
850 	/* If not searching for directory entry. */
851 
852 	/* If item is found. */
853 	retval = search_item(sb, p_cpu_key, search_path);
854 	if (retval == IO_ERROR)
855 		return retval;
856 	if (retval == ITEM_FOUND) {
857 
858 		RFALSE(!ih_item_len
859 		       (item_head
860 			(PATH_PLAST_BUFFER(search_path),
861 			 PATH_LAST_POSITION(search_path))),
862 		       "PAP-5165: item length equals zero");
863 
864 		pos_in_item(search_path) = 0;
865 		return POSITION_FOUND;
866 	}
867 
868 	RFALSE(!PATH_LAST_POSITION(search_path),
869 	       "PAP-5170: position equals zero");
870 
871 	/* Item is not found. Set path to the previous item. */
872 	p_le_ih =
873 	    item_head(PATH_PLAST_BUFFER(search_path),
874 			   --PATH_LAST_POSITION(search_path));
875 	blk_size = sb->s_blocksize;
876 
877 	if (comp_short_keys(&p_le_ih->ih_key, p_cpu_key))
878 		return FILE_NOT_FOUND;
879 
880 	/* FIXME: quite ugly this far */
881 
882 	item_offset = le_ih_k_offset(p_le_ih);
883 	offset = cpu_key_k_offset(p_cpu_key);
884 
885 	/* Needed byte is contained in the item pointed to by the path. */
886 	if (item_offset <= offset &&
887 	    item_offset + op_bytes_number(p_le_ih, blk_size) > offset) {
888 		pos_in_item(search_path) = offset - item_offset;
889 		if (is_indirect_le_ih(p_le_ih)) {
890 			pos_in_item(search_path) /= blk_size;
891 		}
892 		return POSITION_FOUND;
893 	}
894 
895 	/*
896 	 * Needed byte is not contained in the item pointed to by the
897 	 * path. Set pos_in_item out of the item.
898 	 */
899 	if (is_indirect_le_ih(p_le_ih))
900 		pos_in_item(search_path) =
901 		    ih_item_len(p_le_ih) / UNFM_P_SIZE;
902 	else
903 		pos_in_item(search_path) = ih_item_len(p_le_ih);
904 
905 	return POSITION_NOT_FOUND;
906 }
907 
908 /* Compare given item and item pointed to by the path. */
909 int comp_items(const struct item_head *stored_ih, const struct treepath *path)
910 {
911 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
912 	struct item_head *ih;
913 
914 	/* Last buffer at the path is not in the tree. */
915 	if (!B_IS_IN_TREE(bh))
916 		return 1;
917 
918 	/* Last path position is invalid. */
919 	if (PATH_LAST_POSITION(path) >= B_NR_ITEMS(bh))
920 		return 1;
921 
922 	/* we need only to know, whether it is the same item */
923 	ih = tp_item_head(path);
924 	return memcmp(stored_ih, ih, IH_SIZE);
925 }
926 
927 /* prepare for delete or cut of direct item */
928 static inline int prepare_for_direct_item(struct treepath *path,
929 					  struct item_head *le_ih,
930 					  struct inode *inode,
931 					  loff_t new_file_length, int *cut_size)
932 {
933 	loff_t round_len;
934 
935 	if (new_file_length == max_reiserfs_offset(inode)) {
936 		/* item has to be deleted */
937 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
938 		return M_DELETE;
939 	}
940 	/* new file gets truncated */
941 	if (get_inode_item_key_version(inode) == KEY_FORMAT_3_6) {
942 		round_len = ROUND_UP(new_file_length);
943 		/* this was new_file_length < le_ih ... */
944 		if (round_len < le_ih_k_offset(le_ih)) {
945 			*cut_size = -(IH_SIZE + ih_item_len(le_ih));
946 			return M_DELETE;	/* Delete this item. */
947 		}
948 		/* Calculate first position and size for cutting from item. */
949 		pos_in_item(path) = round_len - (le_ih_k_offset(le_ih) - 1);
950 		*cut_size = -(ih_item_len(le_ih) - pos_in_item(path));
951 
952 		return M_CUT;	/* Cut from this item. */
953 	}
954 
955 	/* old file: items may have any length */
956 
957 	if (new_file_length < le_ih_k_offset(le_ih)) {
958 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
959 		return M_DELETE;	/* Delete this item. */
960 	}
961 
962 	/* Calculate first position and size for cutting from item. */
963 	*cut_size = -(ih_item_len(le_ih) -
964 		      (pos_in_item(path) =
965 		       new_file_length + 1 - le_ih_k_offset(le_ih)));
966 	return M_CUT;		/* Cut from this item. */
967 }
968 
969 static inline int prepare_for_direntry_item(struct treepath *path,
970 					    struct item_head *le_ih,
971 					    struct inode *inode,
972 					    loff_t new_file_length,
973 					    int *cut_size)
974 {
975 	if (le_ih_k_offset(le_ih) == DOT_OFFSET &&
976 	    new_file_length == max_reiserfs_offset(inode)) {
977 		RFALSE(ih_entry_count(le_ih) != 2,
978 		       "PAP-5220: incorrect empty directory item (%h)", le_ih);
979 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
980 		/* Delete the directory item containing "." and ".." entry. */
981 		return M_DELETE;
982 	}
983 
984 	if (ih_entry_count(le_ih) == 1) {
985 		/*
986 		 * Delete the directory item such as there is one record only
987 		 * in this item
988 		 */
989 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
990 		return M_DELETE;
991 	}
992 
993 	/* Cut one record from the directory item. */
994 	*cut_size =
995 	    -(DEH_SIZE +
996 	      entry_length(get_last_bh(path), le_ih, pos_in_item(path)));
997 	return M_CUT;
998 }
999 
1000 #define JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD (2 * JOURNAL_PER_BALANCE_CNT + 1)
1001 
1002 /*
1003  * If the path points to a directory or direct item, calculate mode
1004  * and the size cut, for balance.
1005  * If the path points to an indirect item, remove some number of its
1006  * unformatted nodes.
1007  * In case of file truncate calculate whether this item must be
1008  * deleted/truncated or last unformatted node of this item will be
1009  * converted to a direct item.
1010  * This function returns a determination of what balance mode the
1011  * calling function should employ.
1012  */
1013 static char prepare_for_delete_or_cut(struct reiserfs_transaction_handle *th,
1014 				      struct inode *inode,
1015 				      struct treepath *path,
1016 				      const struct cpu_key *item_key,
1017 				      /*
1018 				       * Number of unformatted nodes
1019 				       * which were removed from end
1020 				       * of the file.
1021 				       */
1022 				      int *removed,
1023 				      int *cut_size,
1024 				      /* MAX_KEY_OFFSET in case of delete. */
1025 				      unsigned long long new_file_length
1026     )
1027 {
1028 	struct super_block *sb = inode->i_sb;
1029 	struct item_head *p_le_ih = tp_item_head(path);
1030 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
1031 
1032 	BUG_ON(!th->t_trans_id);
1033 
1034 	/* Stat_data item. */
1035 	if (is_statdata_le_ih(p_le_ih)) {
1036 
1037 		RFALSE(new_file_length != max_reiserfs_offset(inode),
1038 		       "PAP-5210: mode must be M_DELETE");
1039 
1040 		*cut_size = -(IH_SIZE + ih_item_len(p_le_ih));
1041 		return M_DELETE;
1042 	}
1043 
1044 	/* Directory item. */
1045 	if (is_direntry_le_ih(p_le_ih))
1046 		return prepare_for_direntry_item(path, p_le_ih, inode,
1047 						 new_file_length,
1048 						 cut_size);
1049 
1050 	/* Direct item. */
1051 	if (is_direct_le_ih(p_le_ih))
1052 		return prepare_for_direct_item(path, p_le_ih, inode,
1053 					       new_file_length, cut_size);
1054 
1055 	/* Case of an indirect item. */
1056 	{
1057 	    int blk_size = sb->s_blocksize;
1058 	    struct item_head s_ih;
1059 	    int need_re_search;
1060 	    int delete = 0;
1061 	    int result = M_CUT;
1062 	    int pos = 0;
1063 
1064 	    if ( new_file_length == max_reiserfs_offset (inode) ) {
1065 		/*
1066 		 * prepare_for_delete_or_cut() is called by
1067 		 * reiserfs_delete_item()
1068 		 */
1069 		new_file_length = 0;
1070 		delete = 1;
1071 	    }
1072 
1073 	    do {
1074 		need_re_search = 0;
1075 		*cut_size = 0;
1076 		bh = PATH_PLAST_BUFFER(path);
1077 		copy_item_head(&s_ih, tp_item_head(path));
1078 		pos = I_UNFM_NUM(&s_ih);
1079 
1080 		while (le_ih_k_offset (&s_ih) + (pos - 1) * blk_size > new_file_length) {
1081 		    __le32 *unfm;
1082 		    __u32 block;
1083 
1084 		    /*
1085 		     * Each unformatted block deletion may involve
1086 		     * one additional bitmap block into the transaction,
1087 		     * thereby the initial journal space reservation
1088 		     * might not be enough.
1089 		     */
1090 		    if (!delete && (*cut_size) != 0 &&
1091 			reiserfs_transaction_free_space(th) < JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD)
1092 			break;
1093 
1094 		    unfm = (__le32 *)ih_item_body(bh, &s_ih) + pos - 1;
1095 		    block = get_block_num(unfm, 0);
1096 
1097 		    if (block != 0) {
1098 			reiserfs_prepare_for_journal(sb, bh, 1);
1099 			put_block_num(unfm, 0, 0);
1100 			journal_mark_dirty(th, bh);
1101 			reiserfs_free_block(th, inode, block, 1);
1102 		    }
1103 
1104 		    reiserfs_cond_resched(sb);
1105 
1106 		    if (item_moved (&s_ih, path))  {
1107 			need_re_search = 1;
1108 			break;
1109 		    }
1110 
1111 		    pos --;
1112 		    (*removed)++;
1113 		    (*cut_size) -= UNFM_P_SIZE;
1114 
1115 		    if (pos == 0) {
1116 			(*cut_size) -= IH_SIZE;
1117 			result = M_DELETE;
1118 			break;
1119 		    }
1120 		}
1121 		/*
1122 		 * a trick.  If the buffer has been logged, this will
1123 		 * do nothing.  If we've broken the loop without logging
1124 		 * it, it will restore the buffer
1125 		 */
1126 		reiserfs_restore_prepared_buffer(sb, bh);
1127 	    } while (need_re_search &&
1128 		     search_for_position_by_key(sb, item_key, path) == POSITION_FOUND);
1129 	    pos_in_item(path) = pos * UNFM_P_SIZE;
1130 
1131 	    if (*cut_size == 0) {
1132 		/*
1133 		 * Nothing was cut. maybe convert last unformatted node to the
1134 		 * direct item?
1135 		 */
1136 		result = M_CONVERT;
1137 	    }
1138 	    return result;
1139 	}
1140 }
1141 
1142 /* Calculate number of bytes which will be deleted or cut during balance */
1143 static int calc_deleted_bytes_number(struct tree_balance *tb, char mode)
1144 {
1145 	int del_size;
1146 	struct item_head *p_le_ih = tp_item_head(tb->tb_path);
1147 
1148 	if (is_statdata_le_ih(p_le_ih))
1149 		return 0;
1150 
1151 	del_size =
1152 	    (mode ==
1153 	     M_DELETE) ? ih_item_len(p_le_ih) : -tb->insert_size[0];
1154 	if (is_direntry_le_ih(p_le_ih)) {
1155 		/*
1156 		 * return EMPTY_DIR_SIZE; We delete emty directories only.
1157 		 * we can't use EMPTY_DIR_SIZE, as old format dirs have a
1158 		 * different empty size.  ick. FIXME, is this right?
1159 		 */
1160 		return del_size;
1161 	}
1162 
1163 	if (is_indirect_le_ih(p_le_ih))
1164 		del_size = (del_size / UNFM_P_SIZE) *
1165 				(PATH_PLAST_BUFFER(tb->tb_path)->b_size);
1166 	return del_size;
1167 }
1168 
1169 static void init_tb_struct(struct reiserfs_transaction_handle *th,
1170 			   struct tree_balance *tb,
1171 			   struct super_block *sb,
1172 			   struct treepath *path, int size)
1173 {
1174 
1175 	BUG_ON(!th->t_trans_id);
1176 
1177 	memset(tb, '\0', sizeof(struct tree_balance));
1178 	tb->transaction_handle = th;
1179 	tb->tb_sb = sb;
1180 	tb->tb_path = path;
1181 	PATH_OFFSET_PBUFFER(path, ILLEGAL_PATH_ELEMENT_OFFSET) = NULL;
1182 	PATH_OFFSET_POSITION(path, ILLEGAL_PATH_ELEMENT_OFFSET) = 0;
1183 	tb->insert_size[0] = size;
1184 }
1185 
1186 void padd_item(char *item, int total_length, int length)
1187 {
1188 	int i;
1189 
1190 	for (i = total_length; i > length;)
1191 		item[--i] = 0;
1192 }
1193 
1194 #ifdef REISERQUOTA_DEBUG
1195 char key2type(struct reiserfs_key *ih)
1196 {
1197 	if (is_direntry_le_key(2, ih))
1198 		return 'd';
1199 	if (is_direct_le_key(2, ih))
1200 		return 'D';
1201 	if (is_indirect_le_key(2, ih))
1202 		return 'i';
1203 	if (is_statdata_le_key(2, ih))
1204 		return 's';
1205 	return 'u';
1206 }
1207 
1208 char head2type(struct item_head *ih)
1209 {
1210 	if (is_direntry_le_ih(ih))
1211 		return 'd';
1212 	if (is_direct_le_ih(ih))
1213 		return 'D';
1214 	if (is_indirect_le_ih(ih))
1215 		return 'i';
1216 	if (is_statdata_le_ih(ih))
1217 		return 's';
1218 	return 'u';
1219 }
1220 #endif
1221 
1222 /*
1223  * Delete object item.
1224  * th       - active transaction handle
1225  * path     - path to the deleted item
1226  * item_key - key to search for the deleted item
1227  * indode   - used for updating i_blocks and quotas
1228  * un_bh    - NULL or unformatted node pointer
1229  */
1230 int reiserfs_delete_item(struct reiserfs_transaction_handle *th,
1231 			 struct treepath *path, const struct cpu_key *item_key,
1232 			 struct inode *inode, struct buffer_head *un_bh)
1233 {
1234 	struct super_block *sb = inode->i_sb;
1235 	struct tree_balance s_del_balance;
1236 	struct item_head s_ih;
1237 	struct item_head *q_ih;
1238 	int quota_cut_bytes;
1239 	int ret_value, del_size, removed;
1240 	int depth;
1241 
1242 #ifdef CONFIG_REISERFS_CHECK
1243 	char mode;
1244 	int iter = 0;
1245 #endif
1246 
1247 	BUG_ON(!th->t_trans_id);
1248 
1249 	init_tb_struct(th, &s_del_balance, sb, path,
1250 		       0 /*size is unknown */ );
1251 
1252 	while (1) {
1253 		removed = 0;
1254 
1255 #ifdef CONFIG_REISERFS_CHECK
1256 		iter++;
1257 		mode =
1258 #endif
1259 		    prepare_for_delete_or_cut(th, inode, path,
1260 					      item_key, &removed,
1261 					      &del_size,
1262 					      max_reiserfs_offset(inode));
1263 
1264 		RFALSE(mode != M_DELETE, "PAP-5320: mode must be M_DELETE");
1265 
1266 		copy_item_head(&s_ih, tp_item_head(path));
1267 		s_del_balance.insert_size[0] = del_size;
1268 
1269 		ret_value = fix_nodes(M_DELETE, &s_del_balance, NULL, NULL);
1270 		if (ret_value != REPEAT_SEARCH)
1271 			break;
1272 
1273 		PROC_INFO_INC(sb, delete_item_restarted);
1274 
1275 		/* file system changed, repeat search */
1276 		ret_value =
1277 		    search_for_position_by_key(sb, item_key, path);
1278 		if (ret_value == IO_ERROR)
1279 			break;
1280 		if (ret_value == FILE_NOT_FOUND) {
1281 			reiserfs_warning(sb, "vs-5340",
1282 					 "no items of the file %K found",
1283 					 item_key);
1284 			break;
1285 		}
1286 	}			/* while (1) */
1287 
1288 	if (ret_value != CARRY_ON) {
1289 		unfix_nodes(&s_del_balance);
1290 		return 0;
1291 	}
1292 
1293 	/* reiserfs_delete_item returns item length when success */
1294 	ret_value = calc_deleted_bytes_number(&s_del_balance, M_DELETE);
1295 	q_ih = tp_item_head(path);
1296 	quota_cut_bytes = ih_item_len(q_ih);
1297 
1298 	/*
1299 	 * hack so the quota code doesn't have to guess if the file has a
1300 	 * tail.  On tail insert, we allocate quota for 1 unformatted node.
1301 	 * We test the offset because the tail might have been
1302 	 * split into multiple items, and we only want to decrement for
1303 	 * the unfm node once
1304 	 */
1305 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(q_ih)) {
1306 		if ((le_ih_k_offset(q_ih) & (sb->s_blocksize - 1)) == 1) {
1307 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1308 		} else {
1309 			quota_cut_bytes = 0;
1310 		}
1311 	}
1312 
1313 	if (un_bh) {
1314 		int off;
1315 		char *data;
1316 
1317 		/*
1318 		 * We are in direct2indirect conversion, so move tail contents
1319 		 * to the unformatted node
1320 		 */
1321 		/*
1322 		 * note, we do the copy before preparing the buffer because we
1323 		 * don't care about the contents of the unformatted node yet.
1324 		 * the only thing we really care about is the direct item's
1325 		 * data is in the unformatted node.
1326 		 *
1327 		 * Otherwise, we would have to call
1328 		 * reiserfs_prepare_for_journal on the unformatted node,
1329 		 * which might schedule, meaning we'd have to loop all the
1330 		 * way back up to the start of the while loop.
1331 		 *
1332 		 * The unformatted node must be dirtied later on.  We can't be
1333 		 * sure here if the entire tail has been deleted yet.
1334 		 *
1335 		 * un_bh is from the page cache (all unformatted nodes are
1336 		 * from the page cache) and might be a highmem page.  So, we
1337 		 * can't use un_bh->b_data.
1338 		 * -clm
1339 		 */
1340 
1341 		data = kmap_atomic(un_bh->b_page);
1342 		off = ((le_ih_k_offset(&s_ih) - 1) & (PAGE_SIZE - 1));
1343 		memcpy(data + off,
1344 		       ih_item_body(PATH_PLAST_BUFFER(path), &s_ih),
1345 		       ret_value);
1346 		kunmap_atomic(data);
1347 	}
1348 
1349 	/* Perform balancing after all resources have been collected at once. */
1350 	do_balance(&s_del_balance, NULL, NULL, M_DELETE);
1351 
1352 #ifdef REISERQUOTA_DEBUG
1353 	reiserfs_debug(sb, REISERFS_DEBUG_CODE,
1354 		       "reiserquota delete_item(): freeing %u, id=%u type=%c",
1355 		       quota_cut_bytes, inode->i_uid, head2type(&s_ih));
1356 #endif
1357 	depth = reiserfs_write_unlock_nested(inode->i_sb);
1358 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1359 	reiserfs_write_lock_nested(inode->i_sb, depth);
1360 
1361 	/* Return deleted body length */
1362 	return ret_value;
1363 }
1364 
1365 /*
1366  * Summary Of Mechanisms For Handling Collisions Between Processes:
1367  *
1368  *  deletion of the body of the object is performed by iput(), with the
1369  *  result that if multiple processes are operating on a file, the
1370  *  deletion of the body of the file is deferred until the last process
1371  *  that has an open inode performs its iput().
1372  *
1373  *  writes and truncates are protected from collisions by use of
1374  *  semaphores.
1375  *
1376  *  creates, linking, and mknod are protected from collisions with other
1377  *  processes by making the reiserfs_add_entry() the last step in the
1378  *  creation, and then rolling back all changes if there was a collision.
1379  *  - Hans
1380 */
1381 
1382 /* this deletes item which never gets split */
1383 void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
1384 				struct inode *inode, struct reiserfs_key *key)
1385 {
1386 	struct super_block *sb = th->t_super;
1387 	struct tree_balance tb;
1388 	INITIALIZE_PATH(path);
1389 	int item_len = 0;
1390 	int tb_init = 0;
1391 	struct cpu_key cpu_key;
1392 	int retval;
1393 	int quota_cut_bytes = 0;
1394 
1395 	BUG_ON(!th->t_trans_id);
1396 
1397 	le_key2cpu_key(&cpu_key, key);
1398 
1399 	while (1) {
1400 		retval = search_item(th->t_super, &cpu_key, &path);
1401 		if (retval == IO_ERROR) {
1402 			reiserfs_error(th->t_super, "vs-5350",
1403 				       "i/o failure occurred trying "
1404 				       "to delete %K", &cpu_key);
1405 			break;
1406 		}
1407 		if (retval != ITEM_FOUND) {
1408 			pathrelse(&path);
1409 			/*
1410 			 * No need for a warning, if there is just no free
1411 			 * space to insert '..' item into the
1412 			 * newly-created subdir
1413 			 */
1414 			if (!
1415 			    ((unsigned long long)
1416 			     GET_HASH_VALUE(le_key_k_offset
1417 					    (le_key_version(key), key)) == 0
1418 			     && (unsigned long long)
1419 			     GET_GENERATION_NUMBER(le_key_k_offset
1420 						   (le_key_version(key),
1421 						    key)) == 1))
1422 				reiserfs_warning(th->t_super, "vs-5355",
1423 						 "%k not found", key);
1424 			break;
1425 		}
1426 		if (!tb_init) {
1427 			tb_init = 1;
1428 			item_len = ih_item_len(tp_item_head(&path));
1429 			init_tb_struct(th, &tb, th->t_super, &path,
1430 				       -(IH_SIZE + item_len));
1431 		}
1432 		quota_cut_bytes = ih_item_len(tp_item_head(&path));
1433 
1434 		retval = fix_nodes(M_DELETE, &tb, NULL, NULL);
1435 		if (retval == REPEAT_SEARCH) {
1436 			PROC_INFO_INC(th->t_super, delete_solid_item_restarted);
1437 			continue;
1438 		}
1439 
1440 		if (retval == CARRY_ON) {
1441 			do_balance(&tb, NULL, NULL, M_DELETE);
1442 			/*
1443 			 * Should we count quota for item? (we don't
1444 			 * count quotas for save-links)
1445 			 */
1446 			if (inode) {
1447 				int depth;
1448 #ifdef REISERQUOTA_DEBUG
1449 				reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
1450 					       "reiserquota delete_solid_item(): freeing %u id=%u type=%c",
1451 					       quota_cut_bytes, inode->i_uid,
1452 					       key2type(key));
1453 #endif
1454 				depth = reiserfs_write_unlock_nested(sb);
1455 				dquot_free_space_nodirty(inode,
1456 							 quota_cut_bytes);
1457 				reiserfs_write_lock_nested(sb, depth);
1458 			}
1459 			break;
1460 		}
1461 
1462 		/* IO_ERROR, NO_DISK_SPACE, etc */
1463 		reiserfs_warning(th->t_super, "vs-5360",
1464 				 "could not delete %K due to fix_nodes failure",
1465 				 &cpu_key);
1466 		unfix_nodes(&tb);
1467 		break;
1468 	}
1469 
1470 	reiserfs_check_path(&path);
1471 }
1472 
1473 int reiserfs_delete_object(struct reiserfs_transaction_handle *th,
1474 			   struct inode *inode)
1475 {
1476 	int err;
1477 	inode->i_size = 0;
1478 	BUG_ON(!th->t_trans_id);
1479 
1480 	/* for directory this deletes item containing "." and ".." */
1481 	err =
1482 	    reiserfs_do_truncate(th, inode, NULL, 0 /*no timestamp updates */ );
1483 	if (err)
1484 		return err;
1485 
1486 #if defined( USE_INODE_GENERATION_COUNTER )
1487 	if (!old_format_only(th->t_super)) {
1488 		__le32 *inode_generation;
1489 
1490 		inode_generation =
1491 		    &REISERFS_SB(th->t_super)->s_rs->s_inode_generation;
1492 		le32_add_cpu(inode_generation, 1);
1493 	}
1494 /* USE_INODE_GENERATION_COUNTER */
1495 #endif
1496 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1497 
1498 	return err;
1499 }
1500 
1501 static void unmap_buffers(struct page *page, loff_t pos)
1502 {
1503 	struct buffer_head *bh;
1504 	struct buffer_head *head;
1505 	struct buffer_head *next;
1506 	unsigned long tail_index;
1507 	unsigned long cur_index;
1508 
1509 	if (page) {
1510 		if (page_has_buffers(page)) {
1511 			tail_index = pos & (PAGE_SIZE - 1);
1512 			cur_index = 0;
1513 			head = page_buffers(page);
1514 			bh = head;
1515 			do {
1516 				next = bh->b_this_page;
1517 
1518 				/*
1519 				 * we want to unmap the buffers that contain
1520 				 * the tail, and all the buffers after it
1521 				 * (since the tail must be at the end of the
1522 				 * file).  We don't want to unmap file data
1523 				 * before the tail, since it might be dirty
1524 				 * and waiting to reach disk
1525 				 */
1526 				cur_index += bh->b_size;
1527 				if (cur_index > tail_index) {
1528 					reiserfs_unmap_buffer(bh);
1529 				}
1530 				bh = next;
1531 			} while (bh != head);
1532 		}
1533 	}
1534 }
1535 
1536 static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
1537 				    struct inode *inode,
1538 				    struct page *page,
1539 				    struct treepath *path,
1540 				    const struct cpu_key *item_key,
1541 				    loff_t new_file_size, char *mode)
1542 {
1543 	struct super_block *sb = inode->i_sb;
1544 	int block_size = sb->s_blocksize;
1545 	int cut_bytes;
1546 	BUG_ON(!th->t_trans_id);
1547 	BUG_ON(new_file_size != inode->i_size);
1548 
1549 	/*
1550 	 * the page being sent in could be NULL if there was an i/o error
1551 	 * reading in the last block.  The user will hit problems trying to
1552 	 * read the file, but for now we just skip the indirect2direct
1553 	 */
1554 	if (atomic_read(&inode->i_count) > 1 ||
1555 	    !tail_has_to_be_packed(inode) ||
1556 	    !page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
1557 		/* leave tail in an unformatted node */
1558 		*mode = M_SKIP_BALANCING;
1559 		cut_bytes =
1560 		    block_size - (new_file_size & (block_size - 1));
1561 		pathrelse(path);
1562 		return cut_bytes;
1563 	}
1564 
1565 	/* Perform the conversion to a direct_item. */
1566 	return indirect2direct(th, inode, page, path, item_key,
1567 			       new_file_size, mode);
1568 }
1569 
1570 /*
1571  * we did indirect_to_direct conversion. And we have inserted direct
1572  * item successesfully, but there were no disk space to cut unfm
1573  * pointer being converted. Therefore we have to delete inserted
1574  * direct item(s)
1575  */
1576 static void indirect_to_direct_roll_back(struct reiserfs_transaction_handle *th,
1577 					 struct inode *inode, struct treepath *path)
1578 {
1579 	struct cpu_key tail_key;
1580 	int tail_len;
1581 	int removed;
1582 	BUG_ON(!th->t_trans_id);
1583 
1584 	make_cpu_key(&tail_key, inode, inode->i_size + 1, TYPE_DIRECT, 4);
1585 	tail_key.key_length = 4;
1586 
1587 	tail_len =
1588 	    (cpu_key_k_offset(&tail_key) & (inode->i_sb->s_blocksize - 1)) - 1;
1589 	while (tail_len) {
1590 		/* look for the last byte of the tail */
1591 		if (search_for_position_by_key(inode->i_sb, &tail_key, path) ==
1592 		    POSITION_NOT_FOUND)
1593 			reiserfs_panic(inode->i_sb, "vs-5615",
1594 				       "found invalid item");
1595 		RFALSE(path->pos_in_item !=
1596 		       ih_item_len(tp_item_head(path)) - 1,
1597 		       "vs-5616: appended bytes found");
1598 		PATH_LAST_POSITION(path)--;
1599 
1600 		removed =
1601 		    reiserfs_delete_item(th, path, &tail_key, inode,
1602 					 NULL /*unbh not needed */ );
1603 		RFALSE(removed <= 0
1604 		       || removed > tail_len,
1605 		       "vs-5617: there was tail %d bytes, removed item length %d bytes",
1606 		       tail_len, removed);
1607 		tail_len -= removed;
1608 		set_cpu_key_k_offset(&tail_key,
1609 				     cpu_key_k_offset(&tail_key) - removed);
1610 	}
1611 	reiserfs_warning(inode->i_sb, "reiserfs-5091", "indirect_to_direct "
1612 			 "conversion has been rolled back due to "
1613 			 "lack of disk space");
1614 	mark_inode_dirty(inode);
1615 }
1616 
1617 /* (Truncate or cut entry) or delete object item. Returns < 0 on failure */
1618 int reiserfs_cut_from_item(struct reiserfs_transaction_handle *th,
1619 			   struct treepath *path,
1620 			   struct cpu_key *item_key,
1621 			   struct inode *inode,
1622 			   struct page *page, loff_t new_file_size)
1623 {
1624 	struct super_block *sb = inode->i_sb;
1625 	/*
1626 	 * Every function which is going to call do_balance must first
1627 	 * create a tree_balance structure.  Then it must fill up this
1628 	 * structure by using the init_tb_struct and fix_nodes functions.
1629 	 * After that we can make tree balancing.
1630 	 */
1631 	struct tree_balance s_cut_balance;
1632 	struct item_head *p_le_ih;
1633 	int cut_size = 0;	/* Amount to be cut. */
1634 	int ret_value = CARRY_ON;
1635 	int removed = 0;	/* Number of the removed unformatted nodes. */
1636 	int is_inode_locked = 0;
1637 	char mode;		/* Mode of the balance. */
1638 	int retval2 = -1;
1639 	int quota_cut_bytes;
1640 	loff_t tail_pos = 0;
1641 	int depth;
1642 
1643 	BUG_ON(!th->t_trans_id);
1644 
1645 	init_tb_struct(th, &s_cut_balance, inode->i_sb, path,
1646 		       cut_size);
1647 
1648 	/*
1649 	 * Repeat this loop until we either cut the item without needing
1650 	 * to balance, or we fix_nodes without schedule occurring
1651 	 */
1652 	while (1) {
1653 		/*
1654 		 * Determine the balance mode, position of the first byte to
1655 		 * be cut, and size to be cut.  In case of the indirect item
1656 		 * free unformatted nodes which are pointed to by the cut
1657 		 * pointers.
1658 		 */
1659 
1660 		mode =
1661 		    prepare_for_delete_or_cut(th, inode, path,
1662 					      item_key, &removed,
1663 					      &cut_size, new_file_size);
1664 		if (mode == M_CONVERT) {
1665 			/*
1666 			 * convert last unformatted node to direct item or
1667 			 * leave tail in the unformatted node
1668 			 */
1669 			RFALSE(ret_value != CARRY_ON,
1670 			       "PAP-5570: can not convert twice");
1671 
1672 			ret_value =
1673 			    maybe_indirect_to_direct(th, inode, page,
1674 						     path, item_key,
1675 						     new_file_size, &mode);
1676 			if (mode == M_SKIP_BALANCING)
1677 				/* tail has been left in the unformatted node */
1678 				return ret_value;
1679 
1680 			is_inode_locked = 1;
1681 
1682 			/*
1683 			 * removing of last unformatted node will
1684 			 * change value we have to return to truncate.
1685 			 * Save it
1686 			 */
1687 			retval2 = ret_value;
1688 
1689 			/*
1690 			 * So, we have performed the first part of the
1691 			 * conversion:
1692 			 * inserting the new direct item.  Now we are
1693 			 * removing the last unformatted node pointer.
1694 			 * Set key to search for it.
1695 			 */
1696 			set_cpu_key_k_type(item_key, TYPE_INDIRECT);
1697 			item_key->key_length = 4;
1698 			new_file_size -=
1699 			    (new_file_size & (sb->s_blocksize - 1));
1700 			tail_pos = new_file_size;
1701 			set_cpu_key_k_offset(item_key, new_file_size + 1);
1702 			if (search_for_position_by_key
1703 			    (sb, item_key,
1704 			     path) == POSITION_NOT_FOUND) {
1705 				print_block(PATH_PLAST_BUFFER(path), 3,
1706 					    PATH_LAST_POSITION(path) - 1,
1707 					    PATH_LAST_POSITION(path) + 1);
1708 				reiserfs_panic(sb, "PAP-5580", "item to "
1709 					       "convert does not exist (%K)",
1710 					       item_key);
1711 			}
1712 			continue;
1713 		}
1714 		if (cut_size == 0) {
1715 			pathrelse(path);
1716 			return 0;
1717 		}
1718 
1719 		s_cut_balance.insert_size[0] = cut_size;
1720 
1721 		ret_value = fix_nodes(mode, &s_cut_balance, NULL, NULL);
1722 		if (ret_value != REPEAT_SEARCH)
1723 			break;
1724 
1725 		PROC_INFO_INC(sb, cut_from_item_restarted);
1726 
1727 		ret_value =
1728 		    search_for_position_by_key(sb, item_key, path);
1729 		if (ret_value == POSITION_FOUND)
1730 			continue;
1731 
1732 		reiserfs_warning(sb, "PAP-5610", "item %K not found",
1733 				 item_key);
1734 		unfix_nodes(&s_cut_balance);
1735 		return (ret_value == IO_ERROR) ? -EIO : -ENOENT;
1736 	}			/* while */
1737 
1738 	/* check fix_nodes results (IO_ERROR or NO_DISK_SPACE) */
1739 	if (ret_value != CARRY_ON) {
1740 		if (is_inode_locked) {
1741 			/*
1742 			 * FIXME: this seems to be not needed: we are always
1743 			 * able to cut item
1744 			 */
1745 			indirect_to_direct_roll_back(th, inode, path);
1746 		}
1747 		if (ret_value == NO_DISK_SPACE)
1748 			reiserfs_warning(sb, "reiserfs-5092",
1749 					 "NO_DISK_SPACE");
1750 		unfix_nodes(&s_cut_balance);
1751 		return -EIO;
1752 	}
1753 
1754 	/* go ahead and perform balancing */
1755 
1756 	RFALSE(mode == M_PASTE || mode == M_INSERT, "invalid mode");
1757 
1758 	/* Calculate number of bytes that need to be cut from the item. */
1759 	quota_cut_bytes =
1760 	    (mode ==
1761 	     M_DELETE) ? ih_item_len(tp_item_head(path)) : -s_cut_balance.
1762 	    insert_size[0];
1763 	if (retval2 == -1)
1764 		ret_value = calc_deleted_bytes_number(&s_cut_balance, mode);
1765 	else
1766 		ret_value = retval2;
1767 
1768 	/*
1769 	 * For direct items, we only change the quota when deleting the last
1770 	 * item.
1771 	 */
1772 	p_le_ih = tp_item_head(s_cut_balance.tb_path);
1773 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(p_le_ih)) {
1774 		if (mode == M_DELETE &&
1775 		    (le_ih_k_offset(p_le_ih) & (sb->s_blocksize - 1)) ==
1776 		    1) {
1777 			/* FIXME: this is to keep 3.5 happy */
1778 			REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
1779 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1780 		} else {
1781 			quota_cut_bytes = 0;
1782 		}
1783 	}
1784 #ifdef CONFIG_REISERFS_CHECK
1785 	if (is_inode_locked) {
1786 		struct item_head *le_ih =
1787 		    tp_item_head(s_cut_balance.tb_path);
1788 		/*
1789 		 * we are going to complete indirect2direct conversion. Make
1790 		 * sure, that we exactly remove last unformatted node pointer
1791 		 * of the item
1792 		 */
1793 		if (!is_indirect_le_ih(le_ih))
1794 			reiserfs_panic(sb, "vs-5652",
1795 				       "item must be indirect %h", le_ih);
1796 
1797 		if (mode == M_DELETE && ih_item_len(le_ih) != UNFM_P_SIZE)
1798 			reiserfs_panic(sb, "vs-5653", "completing "
1799 				       "indirect2direct conversion indirect "
1800 				       "item %h being deleted must be of "
1801 				       "4 byte long", le_ih);
1802 
1803 		if (mode == M_CUT
1804 		    && s_cut_balance.insert_size[0] != -UNFM_P_SIZE) {
1805 			reiserfs_panic(sb, "vs-5654", "can not complete "
1806 				       "indirect2direct conversion of %h "
1807 				       "(CUT, insert_size==%d)",
1808 				       le_ih, s_cut_balance.insert_size[0]);
1809 		}
1810 		/*
1811 		 * it would be useful to make sure, that right neighboring
1812 		 * item is direct item of this file
1813 		 */
1814 	}
1815 #endif
1816 
1817 	do_balance(&s_cut_balance, NULL, NULL, mode);
1818 	if (is_inode_locked) {
1819 		/*
1820 		 * we've done an indirect->direct conversion.  when the
1821 		 * data block was freed, it was removed from the list of
1822 		 * blocks that must be flushed before the transaction
1823 		 * commits, make sure to unmap and invalidate it
1824 		 */
1825 		unmap_buffers(page, tail_pos);
1826 		REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
1827 	}
1828 #ifdef REISERQUOTA_DEBUG
1829 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
1830 		       "reiserquota cut_from_item(): freeing %u id=%u type=%c",
1831 		       quota_cut_bytes, inode->i_uid, '?');
1832 #endif
1833 	depth = reiserfs_write_unlock_nested(sb);
1834 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1835 	reiserfs_write_lock_nested(sb, depth);
1836 	return ret_value;
1837 }
1838 
1839 static void truncate_directory(struct reiserfs_transaction_handle *th,
1840 			       struct inode *inode)
1841 {
1842 	BUG_ON(!th->t_trans_id);
1843 	if (inode->i_nlink)
1844 		reiserfs_error(inode->i_sb, "vs-5655", "link count != 0");
1845 
1846 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), DOT_OFFSET);
1847 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_DIRENTRY);
1848 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1849 	reiserfs_update_sd(th, inode);
1850 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), SD_OFFSET);
1851 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_STAT_DATA);
1852 }
1853 
1854 /*
1855  * Truncate file to the new size. Note, this must be called with a
1856  * transaction already started
1857  */
1858 int reiserfs_do_truncate(struct reiserfs_transaction_handle *th,
1859 			 struct inode *inode,	/* ->i_size contains new size */
1860 			 struct page *page,	/* up to date for last block */
1861 			 /*
1862 			  * when it is called by file_release to convert
1863 			  * the tail - no timestamps should be updated
1864 			  */
1865 			 int update_timestamps
1866     )
1867 {
1868 	INITIALIZE_PATH(s_search_path);	/* Path to the current object item. */
1869 	struct item_head *p_le_ih;	/* Pointer to an item header. */
1870 
1871 	/* Key to search for a previous file item. */
1872 	struct cpu_key s_item_key;
1873 	loff_t file_size,	/* Old file size. */
1874 	 new_file_size;	/* New file size. */
1875 	int deleted;		/* Number of deleted or truncated bytes. */
1876 	int retval;
1877 	int err = 0;
1878 
1879 	BUG_ON(!th->t_trans_id);
1880 	if (!
1881 	    (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
1882 	     || S_ISLNK(inode->i_mode)))
1883 		return 0;
1884 
1885 	/* deletion of directory - no need to update timestamps */
1886 	if (S_ISDIR(inode->i_mode)) {
1887 		truncate_directory(th, inode);
1888 		return 0;
1889 	}
1890 
1891 	/* Get new file size. */
1892 	new_file_size = inode->i_size;
1893 
1894 	/* FIXME: note, that key type is unimportant here */
1895 	make_cpu_key(&s_item_key, inode, max_reiserfs_offset(inode),
1896 		     TYPE_DIRECT, 3);
1897 
1898 	retval =
1899 	    search_for_position_by_key(inode->i_sb, &s_item_key,
1900 				       &s_search_path);
1901 	if (retval == IO_ERROR) {
1902 		reiserfs_error(inode->i_sb, "vs-5657",
1903 			       "i/o failure occurred trying to truncate %K",
1904 			       &s_item_key);
1905 		err = -EIO;
1906 		goto out;
1907 	}
1908 	if (retval == POSITION_FOUND || retval == FILE_NOT_FOUND) {
1909 		reiserfs_error(inode->i_sb, "PAP-5660",
1910 			       "wrong result %d of search for %K", retval,
1911 			       &s_item_key);
1912 
1913 		err = -EIO;
1914 		goto out;
1915 	}
1916 
1917 	s_search_path.pos_in_item--;
1918 
1919 	/* Get real file size (total length of all file items) */
1920 	p_le_ih = tp_item_head(&s_search_path);
1921 	if (is_statdata_le_ih(p_le_ih))
1922 		file_size = 0;
1923 	else {
1924 		loff_t offset = le_ih_k_offset(p_le_ih);
1925 		int bytes =
1926 		    op_bytes_number(p_le_ih, inode->i_sb->s_blocksize);
1927 
1928 		/*
1929 		 * this may mismatch with real file size: if last direct item
1930 		 * had no padding zeros and last unformatted node had no free
1931 		 * space, this file would have this file size
1932 		 */
1933 		file_size = offset + bytes - 1;
1934 	}
1935 	/*
1936 	 * are we doing a full truncate or delete, if so
1937 	 * kick in the reada code
1938 	 */
1939 	if (new_file_size == 0)
1940 		s_search_path.reada = PATH_READA | PATH_READA_BACK;
1941 
1942 	if (file_size == 0 || file_size < new_file_size) {
1943 		goto update_and_out;
1944 	}
1945 
1946 	/* Update key to search for the last file item. */
1947 	set_cpu_key_k_offset(&s_item_key, file_size);
1948 
1949 	do {
1950 		/* Cut or delete file item. */
1951 		deleted =
1952 		    reiserfs_cut_from_item(th, &s_search_path, &s_item_key,
1953 					   inode, page, new_file_size);
1954 		if (deleted < 0) {
1955 			reiserfs_warning(inode->i_sb, "vs-5665",
1956 					 "reiserfs_cut_from_item failed");
1957 			reiserfs_check_path(&s_search_path);
1958 			return 0;
1959 		}
1960 
1961 		RFALSE(deleted > file_size,
1962 		       "PAP-5670: reiserfs_cut_from_item: too many bytes deleted: deleted %d, file_size %lu, item_key %K",
1963 		       deleted, file_size, &s_item_key);
1964 
1965 		/* Change key to search the last file item. */
1966 		file_size -= deleted;
1967 
1968 		set_cpu_key_k_offset(&s_item_key, file_size);
1969 
1970 		/*
1971 		 * While there are bytes to truncate and previous
1972 		 * file item is presented in the tree.
1973 		 */
1974 
1975 		/*
1976 		 * This loop could take a really long time, and could log
1977 		 * many more blocks than a transaction can hold.  So, we do
1978 		 * a polite journal end here, and if the transaction needs
1979 		 * ending, we make sure the file is consistent before ending
1980 		 * the current trans and starting a new one
1981 		 */
1982 		if (journal_transaction_should_end(th, 0) ||
1983 		    reiserfs_transaction_free_space(th) <= JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD) {
1984 			pathrelse(&s_search_path);
1985 
1986 			if (update_timestamps) {
1987 				inode->i_mtime = current_time(inode);
1988 				inode->i_ctime = current_time(inode);
1989 			}
1990 			reiserfs_update_sd(th, inode);
1991 
1992 			err = journal_end(th);
1993 			if (err)
1994 				goto out;
1995 			err = journal_begin(th, inode->i_sb,
1996 					    JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD + JOURNAL_PER_BALANCE_CNT * 4) ;
1997 			if (err)
1998 				goto out;
1999 			reiserfs_update_inode_transaction(inode);
2000 		}
2001 	} while (file_size > ROUND_UP(new_file_size) &&
2002 		 search_for_position_by_key(inode->i_sb, &s_item_key,
2003 					    &s_search_path) == POSITION_FOUND);
2004 
2005 	RFALSE(file_size > ROUND_UP(new_file_size),
2006 	       "PAP-5680: truncate did not finish: new_file_size %lld, current %lld, oid %d",
2007 	       new_file_size, file_size, s_item_key.on_disk_key.k_objectid);
2008 
2009 update_and_out:
2010 	if (update_timestamps) {
2011 		/* this is truncate, not file closing */
2012 		inode->i_mtime = current_time(inode);
2013 		inode->i_ctime = current_time(inode);
2014 	}
2015 	reiserfs_update_sd(th, inode);
2016 
2017 out:
2018 	pathrelse(&s_search_path);
2019 	return err;
2020 }
2021 
2022 #ifdef CONFIG_REISERFS_CHECK
2023 /* this makes sure, that we __append__, not overwrite or add holes */
2024 static void check_research_for_paste(struct treepath *path,
2025 				     const struct cpu_key *key)
2026 {
2027 	struct item_head *found_ih = tp_item_head(path);
2028 
2029 	if (is_direct_le_ih(found_ih)) {
2030 		if (le_ih_k_offset(found_ih) +
2031 		    op_bytes_number(found_ih,
2032 				    get_last_bh(path)->b_size) !=
2033 		    cpu_key_k_offset(key)
2034 		    || op_bytes_number(found_ih,
2035 				       get_last_bh(path)->b_size) !=
2036 		    pos_in_item(path))
2037 			reiserfs_panic(NULL, "PAP-5720", "found direct item "
2038 				       "%h or position (%d) does not match "
2039 				       "to key %K", found_ih,
2040 				       pos_in_item(path), key);
2041 	}
2042 	if (is_indirect_le_ih(found_ih)) {
2043 		if (le_ih_k_offset(found_ih) +
2044 		    op_bytes_number(found_ih,
2045 				    get_last_bh(path)->b_size) !=
2046 		    cpu_key_k_offset(key)
2047 		    || I_UNFM_NUM(found_ih) != pos_in_item(path)
2048 		    || get_ih_free_space(found_ih) != 0)
2049 			reiserfs_panic(NULL, "PAP-5730", "found indirect "
2050 				       "item (%h) or position (%d) does not "
2051 				       "match to key (%K)",
2052 				       found_ih, pos_in_item(path), key);
2053 	}
2054 }
2055 #endif				/* config reiserfs check */
2056 
2057 /*
2058  * Paste bytes to the existing item.
2059  * Returns bytes number pasted into the item.
2060  */
2061 int reiserfs_paste_into_item(struct reiserfs_transaction_handle *th,
2062 			     /* Path to the pasted item. */
2063 			     struct treepath *search_path,
2064 			     /* Key to search for the needed item. */
2065 			     const struct cpu_key *key,
2066 			     /* Inode item belongs to */
2067 			     struct inode *inode,
2068 			     /* Pointer to the bytes to paste. */
2069 			     const char *body,
2070 			     /* Size of pasted bytes. */
2071 			     int pasted_size)
2072 {
2073 	struct super_block *sb = inode->i_sb;
2074 	struct tree_balance s_paste_balance;
2075 	int retval;
2076 	int fs_gen;
2077 	int depth;
2078 
2079 	BUG_ON(!th->t_trans_id);
2080 
2081 	fs_gen = get_generation(inode->i_sb);
2082 
2083 #ifdef REISERQUOTA_DEBUG
2084 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2085 		       "reiserquota paste_into_item(): allocating %u id=%u type=%c",
2086 		       pasted_size, inode->i_uid,
2087 		       key2type(&key->on_disk_key));
2088 #endif
2089 
2090 	depth = reiserfs_write_unlock_nested(sb);
2091 	retval = dquot_alloc_space_nodirty(inode, pasted_size);
2092 	reiserfs_write_lock_nested(sb, depth);
2093 	if (retval) {
2094 		pathrelse(search_path);
2095 		return retval;
2096 	}
2097 	init_tb_struct(th, &s_paste_balance, th->t_super, search_path,
2098 		       pasted_size);
2099 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2100 	s_paste_balance.key = key->on_disk_key;
2101 #endif
2102 
2103 	/* DQUOT_* can schedule, must check before the fix_nodes */
2104 	if (fs_changed(fs_gen, inode->i_sb)) {
2105 		goto search_again;
2106 	}
2107 
2108 	while ((retval =
2109 		fix_nodes(M_PASTE, &s_paste_balance, NULL,
2110 			  body)) == REPEAT_SEARCH) {
2111 search_again:
2112 		/* file system changed while we were in the fix_nodes */
2113 		PROC_INFO_INC(th->t_super, paste_into_item_restarted);
2114 		retval =
2115 		    search_for_position_by_key(th->t_super, key,
2116 					       search_path);
2117 		if (retval == IO_ERROR) {
2118 			retval = -EIO;
2119 			goto error_out;
2120 		}
2121 		if (retval == POSITION_FOUND) {
2122 			reiserfs_warning(inode->i_sb, "PAP-5710",
2123 					 "entry or pasted byte (%K) exists",
2124 					 key);
2125 			retval = -EEXIST;
2126 			goto error_out;
2127 		}
2128 #ifdef CONFIG_REISERFS_CHECK
2129 		check_research_for_paste(search_path, key);
2130 #endif
2131 	}
2132 
2133 	/*
2134 	 * Perform balancing after all resources are collected by fix_nodes,
2135 	 * and accessing them will not risk triggering schedule.
2136 	 */
2137 	if (retval == CARRY_ON) {
2138 		do_balance(&s_paste_balance, NULL /*ih */ , body, M_PASTE);
2139 		return 0;
2140 	}
2141 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2142 error_out:
2143 	/* this also releases the path */
2144 	unfix_nodes(&s_paste_balance);
2145 #ifdef REISERQUOTA_DEBUG
2146 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2147 		       "reiserquota paste_into_item(): freeing %u id=%u type=%c",
2148 		       pasted_size, inode->i_uid,
2149 		       key2type(&key->on_disk_key));
2150 #endif
2151 	depth = reiserfs_write_unlock_nested(sb);
2152 	dquot_free_space_nodirty(inode, pasted_size);
2153 	reiserfs_write_lock_nested(sb, depth);
2154 	return retval;
2155 }
2156 
2157 /*
2158  * Insert new item into the buffer at the path.
2159  * th   - active transaction handle
2160  * path - path to the inserted item
2161  * ih   - pointer to the item header to insert
2162  * body - pointer to the bytes to insert
2163  */
2164 int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
2165 			 struct treepath *path, const struct cpu_key *key,
2166 			 struct item_head *ih, struct inode *inode,
2167 			 const char *body)
2168 {
2169 	struct tree_balance s_ins_balance;
2170 	int retval;
2171 	int fs_gen = 0;
2172 	int quota_bytes = 0;
2173 
2174 	BUG_ON(!th->t_trans_id);
2175 
2176 	if (inode) {		/* Do we count quotas for item? */
2177 		int depth;
2178 		fs_gen = get_generation(inode->i_sb);
2179 		quota_bytes = ih_item_len(ih);
2180 
2181 		/*
2182 		 * hack so the quota code doesn't have to guess
2183 		 * if the file has a tail, links are always tails,
2184 		 * so there's no guessing needed
2185 		 */
2186 		if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(ih))
2187 			quota_bytes = inode->i_sb->s_blocksize + UNFM_P_SIZE;
2188 #ifdef REISERQUOTA_DEBUG
2189 		reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2190 			       "reiserquota insert_item(): allocating %u id=%u type=%c",
2191 			       quota_bytes, inode->i_uid, head2type(ih));
2192 #endif
2193 		/*
2194 		 * We can't dirty inode here. It would be immediately
2195 		 * written but appropriate stat item isn't inserted yet...
2196 		 */
2197 		depth = reiserfs_write_unlock_nested(inode->i_sb);
2198 		retval = dquot_alloc_space_nodirty(inode, quota_bytes);
2199 		reiserfs_write_lock_nested(inode->i_sb, depth);
2200 		if (retval) {
2201 			pathrelse(path);
2202 			return retval;
2203 		}
2204 	}
2205 	init_tb_struct(th, &s_ins_balance, th->t_super, path,
2206 		       IH_SIZE + ih_item_len(ih));
2207 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2208 	s_ins_balance.key = key->on_disk_key;
2209 #endif
2210 	/*
2211 	 * DQUOT_* can schedule, must check to be sure calling
2212 	 * fix_nodes is safe
2213 	 */
2214 	if (inode && fs_changed(fs_gen, inode->i_sb)) {
2215 		goto search_again;
2216 	}
2217 
2218 	while ((retval =
2219 		fix_nodes(M_INSERT, &s_ins_balance, ih,
2220 			  body)) == REPEAT_SEARCH) {
2221 search_again:
2222 		/* file system changed while we were in the fix_nodes */
2223 		PROC_INFO_INC(th->t_super, insert_item_restarted);
2224 		retval = search_item(th->t_super, key, path);
2225 		if (retval == IO_ERROR) {
2226 			retval = -EIO;
2227 			goto error_out;
2228 		}
2229 		if (retval == ITEM_FOUND) {
2230 			reiserfs_warning(th->t_super, "PAP-5760",
2231 					 "key %K already exists in the tree",
2232 					 key);
2233 			retval = -EEXIST;
2234 			goto error_out;
2235 		}
2236 	}
2237 
2238 	/* make balancing after all resources will be collected at a time */
2239 	if (retval == CARRY_ON) {
2240 		do_balance(&s_ins_balance, ih, body, M_INSERT);
2241 		return 0;
2242 	}
2243 
2244 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2245 error_out:
2246 	/* also releases the path */
2247 	unfix_nodes(&s_ins_balance);
2248 #ifdef REISERQUOTA_DEBUG
2249 	if (inode)
2250 		reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
2251 		       "reiserquota insert_item(): freeing %u id=%u type=%c",
2252 		       quota_bytes, inode->i_uid, head2type(ih));
2253 #endif
2254 	if (inode) {
2255 		int depth = reiserfs_write_unlock_nested(inode->i_sb);
2256 		dquot_free_space_nodirty(inode, quota_bytes);
2257 		reiserfs_write_lock_nested(inode->i_sb, depth);
2258 	}
2259 	return retval;
2260 }
2261