xref: /openbmc/linux/fs/reiserfs/stree.c (revision 78700c0a)
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 "reiserfs.h"
15 #include <linux/buffer_head.h>
16 #include <linux/quotaops.h>
17 
18 /* Does the buffer contain a disk block which is in the tree. */
19 inline int B_IS_IN_TREE(const struct buffer_head *bh)
20 {
21 
22 	RFALSE(B_LEVEL(bh) > MAX_HEIGHT,
23 	       "PAP-1010: block (%b) has too big level (%z)", bh, bh);
24 
25 	return (B_LEVEL(bh) != FREE_LEVEL);
26 }
27 
28 /* to get item head in le form */
29 inline void copy_item_head(struct item_head *to,
30 			   const struct item_head *from)
31 {
32 	memcpy(to, from, IH_SIZE);
33 }
34 
35 /*
36  * k1 is pointer to on-disk structure which is stored in little-endian
37  * form. k2 is pointer to cpu variable. For key of items of the same
38  * object this returns 0.
39  * Returns: -1 if key1 < key2
40  * 0 if key1 == key2
41  * 1 if key1 > key2
42  */
43 inline int comp_short_keys(const struct reiserfs_key *le_key,
44 			   const struct cpu_key *cpu_key)
45 {
46 	__u32 n;
47 	n = le32_to_cpu(le_key->k_dir_id);
48 	if (n < cpu_key->on_disk_key.k_dir_id)
49 		return -1;
50 	if (n > cpu_key->on_disk_key.k_dir_id)
51 		return 1;
52 	n = le32_to_cpu(le_key->k_objectid);
53 	if (n < cpu_key->on_disk_key.k_objectid)
54 		return -1;
55 	if (n > cpu_key->on_disk_key.k_objectid)
56 		return 1;
57 	return 0;
58 }
59 
60 /*
61  * k1 is pointer to on-disk structure which is stored in little-endian
62  * form. k2 is pointer to cpu variable.
63  * Compare keys using all 4 key fields.
64  * Returns: -1 if key1 < key2 0
65  * if key1 = key2 1 if key1 > key2
66  */
67 static inline int comp_keys(const struct reiserfs_key *le_key,
68 			    const struct cpu_key *cpu_key)
69 {
70 	int retval;
71 
72 	retval = comp_short_keys(le_key, cpu_key);
73 	if (retval)
74 		return retval;
75 	if (le_key_k_offset(le_key_version(le_key), le_key) <
76 	    cpu_key_k_offset(cpu_key))
77 		return -1;
78 	if (le_key_k_offset(le_key_version(le_key), le_key) >
79 	    cpu_key_k_offset(cpu_key))
80 		return 1;
81 
82 	if (cpu_key->key_length == 3)
83 		return 0;
84 
85 	/* this part is needed only when tail conversion is in progress */
86 	if (le_key_k_type(le_key_version(le_key), le_key) <
87 	    cpu_key_k_type(cpu_key))
88 		return -1;
89 
90 	if (le_key_k_type(le_key_version(le_key), le_key) >
91 	    cpu_key_k_type(cpu_key))
92 		return 1;
93 
94 	return 0;
95 }
96 
97 inline int comp_short_le_keys(const struct reiserfs_key *key1,
98 			      const struct reiserfs_key *key2)
99 {
100 	__u32 *k1_u32, *k2_u32;
101 	int key_length = REISERFS_SHORT_KEY_LEN;
102 
103 	k1_u32 = (__u32 *) key1;
104 	k2_u32 = (__u32 *) key2;
105 	for (; key_length--; ++k1_u32, ++k2_u32) {
106 		if (le32_to_cpu(*k1_u32) < le32_to_cpu(*k2_u32))
107 			return -1;
108 		if (le32_to_cpu(*k1_u32) > le32_to_cpu(*k2_u32))
109 			return 1;
110 	}
111 	return 0;
112 }
113 
114 inline void le_key2cpu_key(struct cpu_key *to, const struct reiserfs_key *from)
115 {
116 	int version;
117 	to->on_disk_key.k_dir_id = le32_to_cpu(from->k_dir_id);
118 	to->on_disk_key.k_objectid = le32_to_cpu(from->k_objectid);
119 
120 	/* find out version of the key */
121 	version = le_key_version(from);
122 	to->version = version;
123 	to->on_disk_key.k_offset = le_key_k_offset(version, from);
124 	to->on_disk_key.k_type = le_key_k_type(version, from);
125 }
126 
127 /*
128  * this does not say which one is bigger, it only returns 1 if keys
129  * are not equal, 0 otherwise
130  */
131 inline int comp_le_keys(const struct reiserfs_key *k1,
132 			const struct reiserfs_key *k2)
133 {
134 	return memcmp(k1, k2, sizeof(struct reiserfs_key));
135 }
136 
137 /**************************************************************************
138  *  Binary search toolkit function                                        *
139  *  Search for an item in the array by the item key                       *
140  *  Returns:    1 if found,  0 if not found;                              *
141  *        *pos = number of the searched element if found, else the        *
142  *        number of the first element that is larger than key.            *
143  **************************************************************************/
144 /*
145  * For those not familiar with binary search: lbound is the leftmost item
146  * that it could be, rbound the rightmost item that it could be.  We examine
147  * the item halfway between lbound and rbound, and that tells us either
148  * that we can increase lbound, or decrease rbound, or that we have found it,
149  * or if lbound <= rbound that there are no possible items, and we have not
150  * found it. With each examination we cut the number of possible items it
151  * could be by one more than half rounded down, or we find it.
152  */
153 static inline int bin_search(const void *key,	/* Key to search for. */
154 			     const void *base,	/* First item in the array. */
155 			     int num,	/* Number of items in the array. */
156 			     /*
157 			      * Item size in the array.  searched. Lest the
158 			      * reader be confused, note that this is crafted
159 			      * as a general function, and when it is applied
160 			      * specifically to the array of item headers in a
161 			      * node, width is actually the item header size
162 			      * not the item size.
163 			      */
164 			     int width,
165 			     int *pos /* Number of the searched for element. */
166     )
167 {
168 	int rbound, lbound, j;
169 
170 	for (j = ((rbound = num - 1) + (lbound = 0)) / 2;
171 	     lbound <= rbound; j = (rbound + lbound) / 2)
172 		switch (comp_keys
173 			((struct reiserfs_key *)((char *)base + j * width),
174 			 (struct cpu_key *)key)) {
175 		case -1:
176 			lbound = j + 1;
177 			continue;
178 		case 1:
179 			rbound = j - 1;
180 			continue;
181 		case 0:
182 			*pos = j;
183 			return ITEM_FOUND;	/* Key found in the array.  */
184 		}
185 
186 	/*
187 	 * bin_search did not find given key, it returns position of key,
188 	 * that is minimal and greater than the given one.
189 	 */
190 	*pos = lbound;
191 	return ITEM_NOT_FOUND;
192 }
193 
194 
195 /* Minimal possible key. It is never in the tree. */
196 const struct reiserfs_key MIN_KEY = { 0, 0, {{0, 0},} };
197 
198 /* Maximal possible key. It is never in the tree. */
199 static const struct reiserfs_key MAX_KEY = {
200 	cpu_to_le32(0xffffffff),
201 	cpu_to_le32(0xffffffff),
202 	{{cpu_to_le32(0xffffffff),
203 	  cpu_to_le32(0xffffffff)},}
204 };
205 
206 /*
207  * Get delimiting key of the buffer by looking for it in the buffers in the
208  * path, starting from the bottom of the path, and going upwards.  We must
209  * check the path's validity at each step.  If the key is not in the path,
210  * there is no delimiting key in the tree (buffer is first or last buffer
211  * in tree), and in this case we return a special key, either MIN_KEY or
212  * MAX_KEY.
213  */
214 static inline const struct reiserfs_key *get_lkey(const struct treepath *chk_path,
215 						  const struct super_block *sb)
216 {
217 	int position, path_offset = chk_path->path_length;
218 	struct buffer_head *parent;
219 
220 	RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
221 	       "PAP-5010: invalid offset in the path");
222 
223 	/* While not higher in path than first element. */
224 	while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
225 
226 		RFALSE(!buffer_uptodate
227 		       (PATH_OFFSET_PBUFFER(chk_path, path_offset)),
228 		       "PAP-5020: parent is not uptodate");
229 
230 		/* Parent at the path is not in the tree now. */
231 		if (!B_IS_IN_TREE
232 		    (parent =
233 		     PATH_OFFSET_PBUFFER(chk_path, path_offset)))
234 			return &MAX_KEY;
235 		/* Check whether position in the parent is correct. */
236 		if ((position =
237 		     PATH_OFFSET_POSITION(chk_path,
238 					  path_offset)) >
239 		    B_NR_ITEMS(parent))
240 			return &MAX_KEY;
241 		/* Check whether parent at the path really points to the child. */
242 		if (B_N_CHILD_NUM(parent, position) !=
243 		    PATH_OFFSET_PBUFFER(chk_path,
244 					path_offset + 1)->b_blocknr)
245 			return &MAX_KEY;
246 		/*
247 		 * Return delimiting key if position in the parent
248 		 * is not equal to zero.
249 		 */
250 		if (position)
251 			return internal_key(parent, position - 1);
252 	}
253 	/* Return MIN_KEY if we are in the root of the buffer tree. */
254 	if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
255 	    b_blocknr == SB_ROOT_BLOCK(sb))
256 		return &MIN_KEY;
257 	return &MAX_KEY;
258 }
259 
260 /* Get delimiting key of the buffer at the path and its right neighbor. */
261 inline const struct reiserfs_key *get_rkey(const struct treepath *chk_path,
262 					   const struct super_block *sb)
263 {
264 	int position, path_offset = chk_path->path_length;
265 	struct buffer_head *parent;
266 
267 	RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
268 	       "PAP-5030: invalid offset in the path");
269 
270 	while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
271 
272 		RFALSE(!buffer_uptodate
273 		       (PATH_OFFSET_PBUFFER(chk_path, path_offset)),
274 		       "PAP-5040: parent is not uptodate");
275 
276 		/* Parent at the path is not in the tree now. */
277 		if (!B_IS_IN_TREE
278 		    (parent =
279 		     PATH_OFFSET_PBUFFER(chk_path, path_offset)))
280 			return &MIN_KEY;
281 		/* Check whether position in the parent is correct. */
282 		if ((position =
283 		     PATH_OFFSET_POSITION(chk_path,
284 					  path_offset)) >
285 		    B_NR_ITEMS(parent))
286 			return &MIN_KEY;
287 		/*
288 		 * Check whether parent at the path really points
289 		 * to the child.
290 		 */
291 		if (B_N_CHILD_NUM(parent, position) !=
292 		    PATH_OFFSET_PBUFFER(chk_path,
293 					path_offset + 1)->b_blocknr)
294 			return &MIN_KEY;
295 
296 		/*
297 		 * Return delimiting key if position in the parent
298 		 * is not the last one.
299 		 */
300 		if (position != B_NR_ITEMS(parent))
301 			return internal_key(parent, position);
302 	}
303 
304 	/* Return MAX_KEY if we are in the root of the buffer tree. */
305 	if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
306 	    b_blocknr == SB_ROOT_BLOCK(sb))
307 		return &MAX_KEY;
308 	return &MIN_KEY;
309 }
310 
311 /*
312  * Check whether a key is contained in the tree rooted from a buffer at a path.
313  * This works by looking at the left and right delimiting keys for the buffer
314  * in the last path_element in the path.  These delimiting keys are stored
315  * at least one level above that buffer in the tree. If the buffer is the
316  * first or last node in the tree order then one of the delimiting keys may
317  * be absent, and in this case get_lkey and get_rkey return a special key
318  * which is MIN_KEY or MAX_KEY.
319  */
320 static inline int key_in_buffer(
321 				/* Path which should be checked. */
322 				struct treepath *chk_path,
323 				/* Key which should be checked. */
324 				const struct cpu_key *key,
325 				struct super_block *sb
326     )
327 {
328 
329 	RFALSE(!key || chk_path->path_length < FIRST_PATH_ELEMENT_OFFSET
330 	       || chk_path->path_length > MAX_HEIGHT,
331 	       "PAP-5050: pointer to the key(%p) is NULL or invalid path length(%d)",
332 	       key, chk_path->path_length);
333 	RFALSE(!PATH_PLAST_BUFFER(chk_path)->b_bdev,
334 	       "PAP-5060: device must not be NODEV");
335 
336 	if (comp_keys(get_lkey(chk_path, sb), key) == 1)
337 		/* left delimiting key is bigger, that the key we look for */
338 		return 0;
339 	/*  if ( comp_keys(key, get_rkey(chk_path, sb)) != -1 ) */
340 	if (comp_keys(get_rkey(chk_path, sb), key) != 1)
341 		/* key must be less than right delimitiing key */
342 		return 0;
343 	return 1;
344 }
345 
346 int reiserfs_check_path(struct treepath *p)
347 {
348 	RFALSE(p->path_length != ILLEGAL_PATH_ELEMENT_OFFSET,
349 	       "path not properly relsed");
350 	return 0;
351 }
352 
353 /*
354  * Drop the reference to each buffer in a path and restore
355  * dirty bits clean when preparing the buffer for the log.
356  * This version should only be called from fix_nodes()
357  */
358 void pathrelse_and_restore(struct super_block *sb,
359 			   struct treepath *search_path)
360 {
361 	int path_offset = search_path->path_length;
362 
363 	RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
364 	       "clm-4000: invalid path offset");
365 
366 	while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET) {
367 		struct buffer_head *bh;
368 		bh = PATH_OFFSET_PBUFFER(search_path, path_offset--);
369 		reiserfs_restore_prepared_buffer(sb, bh);
370 		brelse(bh);
371 	}
372 	search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
373 }
374 
375 /* Drop the reference to each buffer in a path */
376 void pathrelse(struct treepath *search_path)
377 {
378 	int path_offset = search_path->path_length;
379 
380 	RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
381 	       "PAP-5090: invalid path offset");
382 
383 	while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET)
384 		brelse(PATH_OFFSET_PBUFFER(search_path, path_offset--));
385 
386 	search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
387 }
388 
389 static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
390 {
391 	struct block_head *blkh;
392 	struct item_head *ih;
393 	int used_space;
394 	int prev_location;
395 	int i;
396 	int nr;
397 
398 	blkh = (struct block_head *)buf;
399 	if (blkh_level(blkh) != DISK_LEAF_NODE_LEVEL) {
400 		reiserfs_warning(NULL, "reiserfs-5080",
401 				 "this should be caught earlier");
402 		return 0;
403 	}
404 
405 	nr = blkh_nr_item(blkh);
406 	if (nr < 1 || nr > ((blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN))) {
407 		/* item number is too big or too small */
408 		reiserfs_warning(NULL, "reiserfs-5081",
409 				 "nr_item seems wrong: %z", bh);
410 		return 0;
411 	}
412 	ih = (struct item_head *)(buf + BLKH_SIZE) + nr - 1;
413 	used_space = BLKH_SIZE + IH_SIZE * nr + (blocksize - ih_location(ih));
414 
415 	/* free space does not match to calculated amount of use space */
416 	if (used_space != blocksize - blkh_free_space(blkh)) {
417 		reiserfs_warning(NULL, "reiserfs-5082",
418 				 "free space seems wrong: %z", bh);
419 		return 0;
420 	}
421 	/*
422 	 * FIXME: it is_leaf will hit performance too much - we may have
423 	 * return 1 here
424 	 */
425 
426 	/* check tables of item heads */
427 	ih = (struct item_head *)(buf + BLKH_SIZE);
428 	prev_location = blocksize;
429 	for (i = 0; i < nr; i++, ih++) {
430 		if (le_ih_k_type(ih) == TYPE_ANY) {
431 			reiserfs_warning(NULL, "reiserfs-5083",
432 					 "wrong item type for item %h",
433 					 ih);
434 			return 0;
435 		}
436 		if (ih_location(ih) >= blocksize
437 		    || ih_location(ih) < IH_SIZE * nr) {
438 			reiserfs_warning(NULL, "reiserfs-5084",
439 					 "item location seems wrong: %h",
440 					 ih);
441 			return 0;
442 		}
443 		if (ih_item_len(ih) < 1
444 		    || ih_item_len(ih) > MAX_ITEM_LEN(blocksize)) {
445 			reiserfs_warning(NULL, "reiserfs-5085",
446 					 "item length seems wrong: %h",
447 					 ih);
448 			return 0;
449 		}
450 		if (prev_location - ih_location(ih) != ih_item_len(ih)) {
451 			reiserfs_warning(NULL, "reiserfs-5086",
452 					 "item location seems wrong "
453 					 "(second one): %h", ih);
454 			return 0;
455 		}
456 		prev_location = ih_location(ih);
457 	}
458 
459 	/* one may imagine many more checks */
460 	return 1;
461 }
462 
463 /* returns 1 if buf looks like an internal node, 0 otherwise */
464 static int is_internal(char *buf, int blocksize, struct buffer_head *bh)
465 {
466 	struct block_head *blkh;
467 	int nr;
468 	int used_space;
469 
470 	blkh = (struct block_head *)buf;
471 	nr = blkh_level(blkh);
472 	if (nr <= DISK_LEAF_NODE_LEVEL || nr > MAX_HEIGHT) {
473 		/* this level is not possible for internal nodes */
474 		reiserfs_warning(NULL, "reiserfs-5087",
475 				 "this should be caught earlier");
476 		return 0;
477 	}
478 
479 	nr = blkh_nr_item(blkh);
480 	/* for internal which is not root we might check min number of keys */
481 	if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
482 		reiserfs_warning(NULL, "reiserfs-5088",
483 				 "number of key seems wrong: %z", bh);
484 		return 0;
485 	}
486 
487 	used_space = BLKH_SIZE + KEY_SIZE * nr + DC_SIZE * (nr + 1);
488 	if (used_space != blocksize - blkh_free_space(blkh)) {
489 		reiserfs_warning(NULL, "reiserfs-5089",
490 				 "free space seems wrong: %z", bh);
491 		return 0;
492 	}
493 
494 	/* one may imagine many more checks */
495 	return 1;
496 }
497 
498 /*
499  * make sure that bh contains formatted node of reiserfs tree of
500  * 'level'-th level
501  */
502 static int is_tree_node(struct buffer_head *bh, int level)
503 {
504 	if (B_LEVEL(bh) != level) {
505 		reiserfs_warning(NULL, "reiserfs-5090", "node level %d does "
506 				 "not match to the expected one %d",
507 				 B_LEVEL(bh), level);
508 		return 0;
509 	}
510 	if (level == DISK_LEAF_NODE_LEVEL)
511 		return is_leaf(bh->b_data, bh->b_size, bh);
512 
513 	return is_internal(bh->b_data, bh->b_size, bh);
514 }
515 
516 #define SEARCH_BY_KEY_READA 16
517 
518 /*
519  * The function is NOT SCHEDULE-SAFE!
520  * It might unlock the write lock if we needed to wait for a block
521  * to be read. Note that in this case it won't recover the lock to avoid
522  * high contention resulting from too much lock requests, especially
523  * the caller (search_by_key) will perform other schedule-unsafe
524  * operations just after calling this function.
525  *
526  * @return depth of lock to be restored after read completes
527  */
528 static int search_by_key_reada(struct super_block *s,
529 				struct buffer_head **bh,
530 				b_blocknr_t *b, int num)
531 {
532 	int i, j;
533 	int depth = -1;
534 
535 	for (i = 0; i < num; i++) {
536 		bh[i] = sb_getblk(s, b[i]);
537 	}
538 	/*
539 	 * We are going to read some blocks on which we
540 	 * have a reference. It's safe, though we might be
541 	 * reading blocks concurrently changed if we release
542 	 * the lock. But it's still fine because we check later
543 	 * if the tree changed
544 	 */
545 	for (j = 0; j < i; j++) {
546 		/*
547 		 * note, this needs attention if we are getting rid of the BKL
548 		 * you have to make sure the prepared bit isn't set on this
549 		 * buffer
550 		 */
551 		if (!buffer_uptodate(bh[j])) {
552 			if (depth == -1)
553 				depth = reiserfs_write_unlock_nested(s);
554 			ll_rw_block(READA, 1, bh + j);
555 		}
556 		brelse(bh[j]);
557 	}
558 	return depth;
559 }
560 
561 /*
562  * This function fills up the path from the root to the leaf as it
563  * descends the tree looking for the key.  It uses reiserfs_bread to
564  * try to find buffers in the cache given their block number.  If it
565  * does not find them in the cache it reads them from disk.  For each
566  * node search_by_key finds using reiserfs_bread it then uses
567  * bin_search to look through that node.  bin_search will find the
568  * position of the block_number of the next node if it is looking
569  * through an internal node.  If it is looking through a leaf node
570  * bin_search will find the position of the item which has key either
571  * equal to given key, or which is the maximal key less than the given
572  * key.  search_by_key returns a path that must be checked for the
573  * correctness of the top of the path but need not be checked for the
574  * correctness of the bottom of the path
575  */
576 /*
577  * search_by_key - search for key (and item) in stree
578  * @sb: superblock
579  * @key: pointer to key to search for
580  * @search_path: Allocated and initialized struct treepath; Returned filled
581  *		 on success.
582  * @stop_level: How far down the tree to search, Use DISK_LEAF_NODE_LEVEL to
583  *		stop at leaf level.
584  *
585  * The function is NOT SCHEDULE-SAFE!
586  */
587 int search_by_key(struct super_block *sb, const struct cpu_key *key,
588 		  struct treepath *search_path, int stop_level)
589 {
590 	b_blocknr_t block_number;
591 	int expected_level;
592 	struct buffer_head *bh;
593 	struct path_element *last_element;
594 	int node_level, retval;
595 	int right_neighbor_of_leaf_node;
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 	right_neighbor_of_leaf_node = 0;
617 
618 	/*
619 	 * With each iteration of this loop we search through the items in the
620 	 * current node, and calculate the next current node(next path element)
621 	 * for the next iteration of this loop..
622 	 */
623 	block_number = SB_ROOT_BLOCK(sb);
624 	expected_level = -1;
625 	while (1) {
626 
627 #ifdef CONFIG_REISERFS_CHECK
628 		if (!(++repeat_counter % 50000))
629 			reiserfs_warning(sb, "PAP-5100",
630 					 "%s: there were %d iterations of "
631 					 "while loop looking for key %K",
632 					 current->comm, repeat_counter,
633 					 key);
634 #endif
635 
636 		/* prep path to have another element added to it. */
637 		last_element =
638 		    PATH_OFFSET_PELEMENT(search_path,
639 					 ++search_path->path_length);
640 		fs_gen = get_generation(sb);
641 
642 		/*
643 		 * Read the next tree node, and set the last element
644 		 * in the path to have a pointer to it.
645 		 */
646 		if ((bh = last_element->pe_buffer =
647 		     sb_getblk(sb, block_number))) {
648 
649 			/*
650 			 * We'll need to drop the lock if we encounter any
651 			 * buffers that need to be read. If all of them are
652 			 * already up to date, we don't need to drop the lock.
653 			 */
654 			int depth = -1;
655 
656 			if (!buffer_uptodate(bh) && reada_count > 1)
657 				depth = search_by_key_reada(sb, reada_bh,
658 						    reada_blocks, reada_count);
659 
660 			if (!buffer_uptodate(bh) && depth == -1)
661 				depth = reiserfs_write_unlock_nested(sb);
662 
663 			ll_rw_block(READ, 1, &bh);
664 			wait_on_buffer(bh);
665 
666 			if (depth != -1)
667 				reiserfs_write_lock_nested(sb, depth);
668 			if (!buffer_uptodate(bh))
669 				goto io_error;
670 		} else {
671 io_error:
672 			search_path->path_length--;
673 			pathrelse(search_path);
674 			return IO_ERROR;
675 		}
676 		reada_count = 0;
677 		if (expected_level == -1)
678 			expected_level = SB_TREE_HEIGHT(sb);
679 		expected_level--;
680 
681 		/*
682 		 * It is possible that schedule occurred. We must check
683 		 * whether the key to search is still in the tree rooted
684 		 * from the current buffer. If not then repeat search
685 		 * from the root.
686 		 */
687 		if (fs_changed(fs_gen, sb) &&
688 		    (!B_IS_IN_TREE(bh) ||
689 		     B_LEVEL(bh) != expected_level ||
690 		     !key_in_buffer(search_path, key, sb))) {
691 			PROC_INFO_INC(sb, search_by_key_fs_changed);
692 			PROC_INFO_INC(sb, search_by_key_restarted);
693 			PROC_INFO_INC(sb,
694 				      sbk_restarted[expected_level - 1]);
695 			pathrelse(search_path);
696 
697 			/*
698 			 * Get the root block number so that we can
699 			 * repeat the search starting from the root.
700 			 */
701 			block_number = SB_ROOT_BLOCK(sb);
702 			expected_level = -1;
703 			right_neighbor_of_leaf_node = 0;
704 
705 			/* repeat search from the root */
706 			continue;
707 		}
708 
709 		/*
710 		 * only check that the key is in the buffer if key is not
711 		 * equal to the MAX_KEY. Latter case is only possible in
712 		 * "finish_unfinished()" processing during mount.
713 		 */
714 		RFALSE(comp_keys(&MAX_KEY, key) &&
715 		       !key_in_buffer(search_path, key, sb),
716 		       "PAP-5130: key is not in the buffer");
717 #ifdef CONFIG_REISERFS_CHECK
718 		if (REISERFS_SB(sb)->cur_tb) {
719 			print_cur_tb("5140");
720 			reiserfs_panic(sb, "PAP-5140",
721 				       "schedule occurred in do_balance!");
722 		}
723 #endif
724 
725 		/*
726 		 * make sure, that the node contents look like a node of
727 		 * certain level
728 		 */
729 		if (!is_tree_node(bh, expected_level)) {
730 			reiserfs_error(sb, "vs-5150",
731 				       "invalid format found in block %ld. "
732 				       "Fsck?", bh->b_blocknr);
733 			pathrelse(search_path);
734 			return IO_ERROR;
735 		}
736 
737 		/* ok, we have acquired next formatted node in the tree */
738 		node_level = B_LEVEL(bh);
739 
740 		PROC_INFO_BH_STAT(sb, bh, node_level - 1);
741 
742 		RFALSE(node_level < stop_level,
743 		       "vs-5152: tree level (%d) is less than stop level (%d)",
744 		       node_level, stop_level);
745 
746 		retval = bin_search(key, item_head(bh, 0),
747 				      B_NR_ITEMS(bh),
748 				      (node_level ==
749 				       DISK_LEAF_NODE_LEVEL) ? IH_SIZE :
750 				      KEY_SIZE,
751 				      &last_element->pe_position);
752 		if (node_level == stop_level) {
753 			return retval;
754 		}
755 
756 		/* we are not in the stop level */
757 		/*
758 		 * item has been found, so we choose the pointer which
759 		 * is to the right of the found one
760 		 */
761 		if (retval == ITEM_FOUND)
762 			last_element->pe_position++;
763 
764 		/*
765 		 * if item was not found we choose the position which is to
766 		 * the left of the found item. This requires no code,
767 		 * bin_search did it already.
768 		 */
769 
770 		/*
771 		 * So we have chosen a position in the current node which is
772 		 * an internal node.  Now we calculate child block number by
773 		 * position in the node.
774 		 */
775 		block_number =
776 		    B_N_CHILD_NUM(bh, last_element->pe_position);
777 
778 		/*
779 		 * if we are going to read leaf nodes, try for read
780 		 * ahead as well
781 		 */
782 		if ((search_path->reada & PATH_READA) &&
783 		    node_level == DISK_LEAF_NODE_LEVEL + 1) {
784 			int pos = last_element->pe_position;
785 			int limit = B_NR_ITEMS(bh);
786 			struct reiserfs_key *le_key;
787 
788 			if (search_path->reada & PATH_READA_BACK)
789 				limit = 0;
790 			while (reada_count < SEARCH_BY_KEY_READA) {
791 				if (pos == limit)
792 					break;
793 				reada_blocks[reada_count++] =
794 				    B_N_CHILD_NUM(bh, pos);
795 				if (search_path->reada & PATH_READA_BACK)
796 					pos--;
797 				else
798 					pos++;
799 
800 				/*
801 				 * check to make sure we're in the same object
802 				 */
803 				le_key = internal_key(bh, pos);
804 				if (le32_to_cpu(le_key->k_objectid) !=
805 				    key->on_disk_key.k_objectid) {
806 					break;
807 				}
808 			}
809 		}
810 	}
811 }
812 
813 /*
814  * Form the path to an item and position in this item which contains
815  * file byte defined by key. If there is no such item
816  * corresponding to the key, we point the path to the item with
817  * maximal key less than key, and *pos_in_item is set to one
818  * past the last entry/byte in the item.  If searching for entry in a
819  * directory item, and it is not found, *pos_in_item is set to one
820  * entry more than the entry with maximal key which is less than the
821  * sought key.
822  *
823  * Note that if there is no entry in this same node which is one more,
824  * then we point to an imaginary entry.  for direct items, the
825  * position is in units of bytes, for indirect items the position is
826  * in units of blocknr entries, for directory items the position is in
827  * units of directory entries.
828  */
829 /* The function is NOT SCHEDULE-SAFE! */
830 int search_for_position_by_key(struct super_block *sb,
831 			       /* Key to search (cpu variable) */
832 			       const struct cpu_key *p_cpu_key,
833 			       /* Filled up by this function. */
834 			       struct treepath *search_path)
835 {
836 	struct item_head *p_le_ih;	/* pointer to on-disk structure */
837 	int blk_size;
838 	loff_t item_offset, offset;
839 	struct reiserfs_dir_entry de;
840 	int retval;
841 
842 	/* If searching for directory entry. */
843 	if (is_direntry_cpu_key(p_cpu_key))
844 		return search_by_entry_key(sb, p_cpu_key, search_path,
845 					   &de);
846 
847 	/* If not searching for directory entry. */
848 
849 	/* If item is found. */
850 	retval = search_item(sb, p_cpu_key, search_path);
851 	if (retval == IO_ERROR)
852 		return retval;
853 	if (retval == ITEM_FOUND) {
854 
855 		RFALSE(!ih_item_len
856 		       (item_head
857 			(PATH_PLAST_BUFFER(search_path),
858 			 PATH_LAST_POSITION(search_path))),
859 		       "PAP-5165: item length equals zero");
860 
861 		pos_in_item(search_path) = 0;
862 		return POSITION_FOUND;
863 	}
864 
865 	RFALSE(!PATH_LAST_POSITION(search_path),
866 	       "PAP-5170: position equals zero");
867 
868 	/* Item is not found. Set path to the previous item. */
869 	p_le_ih =
870 	    item_head(PATH_PLAST_BUFFER(search_path),
871 			   --PATH_LAST_POSITION(search_path));
872 	blk_size = sb->s_blocksize;
873 
874 	if (comp_short_keys(&p_le_ih->ih_key, p_cpu_key))
875 		return FILE_NOT_FOUND;
876 
877 	/* FIXME: quite ugly this far */
878 
879 	item_offset = le_ih_k_offset(p_le_ih);
880 	offset = cpu_key_k_offset(p_cpu_key);
881 
882 	/* Needed byte is contained in the item pointed to by the path. */
883 	if (item_offset <= offset &&
884 	    item_offset + op_bytes_number(p_le_ih, blk_size) > offset) {
885 		pos_in_item(search_path) = offset - item_offset;
886 		if (is_indirect_le_ih(p_le_ih)) {
887 			pos_in_item(search_path) /= blk_size;
888 		}
889 		return POSITION_FOUND;
890 	}
891 
892 	/*
893 	 * Needed byte is not contained in the item pointed to by the
894 	 * path. Set pos_in_item out of the item.
895 	 */
896 	if (is_indirect_le_ih(p_le_ih))
897 		pos_in_item(search_path) =
898 		    ih_item_len(p_le_ih) / UNFM_P_SIZE;
899 	else
900 		pos_in_item(search_path) = ih_item_len(p_le_ih);
901 
902 	return POSITION_NOT_FOUND;
903 }
904 
905 /* Compare given item and item pointed to by the path. */
906 int comp_items(const struct item_head *stored_ih, const struct treepath *path)
907 {
908 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
909 	struct item_head *ih;
910 
911 	/* Last buffer at the path is not in the tree. */
912 	if (!B_IS_IN_TREE(bh))
913 		return 1;
914 
915 	/* Last path position is invalid. */
916 	if (PATH_LAST_POSITION(path) >= B_NR_ITEMS(bh))
917 		return 1;
918 
919 	/* we need only to know, whether it is the same item */
920 	ih = tp_item_head(path);
921 	return memcmp(stored_ih, ih, IH_SIZE);
922 }
923 
924 /* unformatted nodes are not logged anymore, ever.  This is safe now */
925 #define held_by_others(bh) (atomic_read(&(bh)->b_count) > 1)
926 
927 /* block can not be forgotten as it is in I/O or held by someone */
928 #define block_in_use(bh) (buffer_locked(bh) || (held_by_others(bh)))
929 
930 /* prepare for delete or cut of direct item */
931 static inline int prepare_for_direct_item(struct treepath *path,
932 					  struct item_head *le_ih,
933 					  struct inode *inode,
934 					  loff_t new_file_length, int *cut_size)
935 {
936 	loff_t round_len;
937 
938 	if (new_file_length == max_reiserfs_offset(inode)) {
939 		/* item has to be deleted */
940 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
941 		return M_DELETE;
942 	}
943 	/* new file gets truncated */
944 	if (get_inode_item_key_version(inode) == KEY_FORMAT_3_6) {
945 		round_len = ROUND_UP(new_file_length);
946 		/* this was new_file_length < le_ih ... */
947 		if (round_len < le_ih_k_offset(le_ih)) {
948 			*cut_size = -(IH_SIZE + ih_item_len(le_ih));
949 			return M_DELETE;	/* Delete this item. */
950 		}
951 		/* Calculate first position and size for cutting from item. */
952 		pos_in_item(path) = round_len - (le_ih_k_offset(le_ih) - 1);
953 		*cut_size = -(ih_item_len(le_ih) - pos_in_item(path));
954 
955 		return M_CUT;	/* Cut from this item. */
956 	}
957 
958 	/* old file: items may have any length */
959 
960 	if (new_file_length < le_ih_k_offset(le_ih)) {
961 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
962 		return M_DELETE;	/* Delete this item. */
963 	}
964 
965 	/* Calculate first position and size for cutting from item. */
966 	*cut_size = -(ih_item_len(le_ih) -
967 		      (pos_in_item(path) =
968 		       new_file_length + 1 - le_ih_k_offset(le_ih)));
969 	return M_CUT;		/* Cut from this item. */
970 }
971 
972 static inline int prepare_for_direntry_item(struct treepath *path,
973 					    struct item_head *le_ih,
974 					    struct inode *inode,
975 					    loff_t new_file_length,
976 					    int *cut_size)
977 {
978 	if (le_ih_k_offset(le_ih) == DOT_OFFSET &&
979 	    new_file_length == max_reiserfs_offset(inode)) {
980 		RFALSE(ih_entry_count(le_ih) != 2,
981 		       "PAP-5220: incorrect empty directory item (%h)", le_ih);
982 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
983 		/* Delete the directory item containing "." and ".." entry. */
984 		return M_DELETE;
985 	}
986 
987 	if (ih_entry_count(le_ih) == 1) {
988 		/*
989 		 * Delete the directory item such as there is one record only
990 		 * in this item
991 		 */
992 		*cut_size = -(IH_SIZE + ih_item_len(le_ih));
993 		return M_DELETE;
994 	}
995 
996 	/* Cut one record from the directory item. */
997 	*cut_size =
998 	    -(DEH_SIZE +
999 	      entry_length(get_last_bh(path), le_ih, pos_in_item(path)));
1000 	return M_CUT;
1001 }
1002 
1003 #define JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD (2 * JOURNAL_PER_BALANCE_CNT + 1)
1004 
1005 /*
1006  * If the path points to a directory or direct item, calculate mode
1007  * and the size cut, for balance.
1008  * If the path points to an indirect item, remove some number of its
1009  * unformatted nodes.
1010  * In case of file truncate calculate whether this item must be
1011  * deleted/truncated or last unformatted node of this item will be
1012  * converted to a direct item.
1013  * This function returns a determination of what balance mode the
1014  * calling function should employ.
1015  */
1016 static char prepare_for_delete_or_cut(struct reiserfs_transaction_handle *th,
1017 				      struct inode *inode,
1018 				      struct treepath *path,
1019 				      const struct cpu_key *item_key,
1020 				      /*
1021 				       * Number of unformatted nodes
1022 				       * which were removed from end
1023 				       * of the file.
1024 				       */
1025 				      int *removed,
1026 				      int *cut_size,
1027 				      /* MAX_KEY_OFFSET in case of delete. */
1028 				      unsigned long long new_file_length
1029     )
1030 {
1031 	struct super_block *sb = inode->i_sb;
1032 	struct item_head *p_le_ih = tp_item_head(path);
1033 	struct buffer_head *bh = PATH_PLAST_BUFFER(path);
1034 
1035 	BUG_ON(!th->t_trans_id);
1036 
1037 	/* Stat_data item. */
1038 	if (is_statdata_le_ih(p_le_ih)) {
1039 
1040 		RFALSE(new_file_length != max_reiserfs_offset(inode),
1041 		       "PAP-5210: mode must be M_DELETE");
1042 
1043 		*cut_size = -(IH_SIZE + ih_item_len(p_le_ih));
1044 		return M_DELETE;
1045 	}
1046 
1047 	/* Directory item. */
1048 	if (is_direntry_le_ih(p_le_ih))
1049 		return prepare_for_direntry_item(path, p_le_ih, inode,
1050 						 new_file_length,
1051 						 cut_size);
1052 
1053 	/* Direct item. */
1054 	if (is_direct_le_ih(p_le_ih))
1055 		return prepare_for_direct_item(path, p_le_ih, inode,
1056 					       new_file_length, cut_size);
1057 
1058 	/* Case of an indirect item. */
1059 	{
1060 	    int blk_size = sb->s_blocksize;
1061 	    struct item_head s_ih;
1062 	    int need_re_search;
1063 	    int delete = 0;
1064 	    int result = M_CUT;
1065 	    int pos = 0;
1066 
1067 	    if ( new_file_length == max_reiserfs_offset (inode) ) {
1068 		/*
1069 		 * prepare_for_delete_or_cut() is called by
1070 		 * reiserfs_delete_item()
1071 		 */
1072 		new_file_length = 0;
1073 		delete = 1;
1074 	    }
1075 
1076 	    do {
1077 		need_re_search = 0;
1078 		*cut_size = 0;
1079 		bh = PATH_PLAST_BUFFER(path);
1080 		copy_item_head(&s_ih, tp_item_head(path));
1081 		pos = I_UNFM_NUM(&s_ih);
1082 
1083 		while (le_ih_k_offset (&s_ih) + (pos - 1) * blk_size > new_file_length) {
1084 		    __le32 *unfm;
1085 		    __u32 block;
1086 
1087 		    /*
1088 		     * Each unformatted block deletion may involve
1089 		     * one additional bitmap block into the transaction,
1090 		     * thereby the initial journal space reservation
1091 		     * might not be enough.
1092 		     */
1093 		    if (!delete && (*cut_size) != 0 &&
1094 			reiserfs_transaction_free_space(th) < JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD)
1095 			break;
1096 
1097 		    unfm = (__le32 *)ih_item_body(bh, &s_ih) + pos - 1;
1098 		    block = get_block_num(unfm, 0);
1099 
1100 		    if (block != 0) {
1101 			reiserfs_prepare_for_journal(sb, bh, 1);
1102 			put_block_num(unfm, 0, 0);
1103 			journal_mark_dirty(th, bh);
1104 			reiserfs_free_block(th, inode, block, 1);
1105 		    }
1106 
1107 		    reiserfs_cond_resched(sb);
1108 
1109 		    if (item_moved (&s_ih, path))  {
1110 			need_re_search = 1;
1111 			break;
1112 		    }
1113 
1114 		    pos --;
1115 		    (*removed)++;
1116 		    (*cut_size) -= UNFM_P_SIZE;
1117 
1118 		    if (pos == 0) {
1119 			(*cut_size) -= IH_SIZE;
1120 			result = M_DELETE;
1121 			break;
1122 		    }
1123 		}
1124 		/*
1125 		 * a trick.  If the buffer has been logged, this will
1126 		 * do nothing.  If we've broken the loop without logging
1127 		 * it, it will restore the buffer
1128 		 */
1129 		reiserfs_restore_prepared_buffer(sb, bh);
1130 	    } while (need_re_search &&
1131 		     search_for_position_by_key(sb, item_key, path) == POSITION_FOUND);
1132 	    pos_in_item(path) = pos * UNFM_P_SIZE;
1133 
1134 	    if (*cut_size == 0) {
1135 		/*
1136 		 * Nothing was cut. maybe convert last unformatted node to the
1137 		 * direct item?
1138 		 */
1139 		result = M_CONVERT;
1140 	    }
1141 	    return result;
1142 	}
1143 }
1144 
1145 /* Calculate number of bytes which will be deleted or cut during balance */
1146 static int calc_deleted_bytes_number(struct tree_balance *tb, char mode)
1147 {
1148 	int del_size;
1149 	struct item_head *p_le_ih = tp_item_head(tb->tb_path);
1150 
1151 	if (is_statdata_le_ih(p_le_ih))
1152 		return 0;
1153 
1154 	del_size =
1155 	    (mode ==
1156 	     M_DELETE) ? ih_item_len(p_le_ih) : -tb->insert_size[0];
1157 	if (is_direntry_le_ih(p_le_ih)) {
1158 		/*
1159 		 * return EMPTY_DIR_SIZE; We delete emty directories only.
1160 		 * we can't use EMPTY_DIR_SIZE, as old format dirs have a
1161 		 * different empty size.  ick. FIXME, is this right?
1162 		 */
1163 		return del_size;
1164 	}
1165 
1166 	if (is_indirect_le_ih(p_le_ih))
1167 		del_size = (del_size / UNFM_P_SIZE) *
1168 				(PATH_PLAST_BUFFER(tb->tb_path)->b_size);
1169 	return del_size;
1170 }
1171 
1172 static void init_tb_struct(struct reiserfs_transaction_handle *th,
1173 			   struct tree_balance *tb,
1174 			   struct super_block *sb,
1175 			   struct treepath *path, int size)
1176 {
1177 
1178 	BUG_ON(!th->t_trans_id);
1179 
1180 	memset(tb, '\0', sizeof(struct tree_balance));
1181 	tb->transaction_handle = th;
1182 	tb->tb_sb = sb;
1183 	tb->tb_path = path;
1184 	PATH_OFFSET_PBUFFER(path, ILLEGAL_PATH_ELEMENT_OFFSET) = NULL;
1185 	PATH_OFFSET_POSITION(path, ILLEGAL_PATH_ELEMENT_OFFSET) = 0;
1186 	tb->insert_size[0] = size;
1187 }
1188 
1189 void padd_item(char *item, int total_length, int length)
1190 {
1191 	int i;
1192 
1193 	for (i = total_length; i > length;)
1194 		item[--i] = 0;
1195 }
1196 
1197 #ifdef REISERQUOTA_DEBUG
1198 char key2type(struct reiserfs_key *ih)
1199 {
1200 	if (is_direntry_le_key(2, ih))
1201 		return 'd';
1202 	if (is_direct_le_key(2, ih))
1203 		return 'D';
1204 	if (is_indirect_le_key(2, ih))
1205 		return 'i';
1206 	if (is_statdata_le_key(2, ih))
1207 		return 's';
1208 	return 'u';
1209 }
1210 
1211 char head2type(struct item_head *ih)
1212 {
1213 	if (is_direntry_le_ih(ih))
1214 		return 'd';
1215 	if (is_direct_le_ih(ih))
1216 		return 'D';
1217 	if (is_indirect_le_ih(ih))
1218 		return 'i';
1219 	if (is_statdata_le_ih(ih))
1220 		return 's';
1221 	return 'u';
1222 }
1223 #endif
1224 
1225 /*
1226  * Delete object item.
1227  * th       - active transaction handle
1228  * path     - path to the deleted item
1229  * item_key - key to search for the deleted item
1230  * indode   - used for updating i_blocks and quotas
1231  * un_bh    - NULL or unformatted node pointer
1232  */
1233 int reiserfs_delete_item(struct reiserfs_transaction_handle *th,
1234 			 struct treepath *path, const struct cpu_key *item_key,
1235 			 struct inode *inode, struct buffer_head *un_bh)
1236 {
1237 	struct super_block *sb = inode->i_sb;
1238 	struct tree_balance s_del_balance;
1239 	struct item_head s_ih;
1240 	struct item_head *q_ih;
1241 	int quota_cut_bytes;
1242 	int ret_value, del_size, removed;
1243 	int depth;
1244 
1245 #ifdef CONFIG_REISERFS_CHECK
1246 	char mode;
1247 	int iter = 0;
1248 #endif
1249 
1250 	BUG_ON(!th->t_trans_id);
1251 
1252 	init_tb_struct(th, &s_del_balance, sb, path,
1253 		       0 /*size is unknown */ );
1254 
1255 	while (1) {
1256 		removed = 0;
1257 
1258 #ifdef CONFIG_REISERFS_CHECK
1259 		iter++;
1260 		mode =
1261 #endif
1262 		    prepare_for_delete_or_cut(th, inode, path,
1263 					      item_key, &removed,
1264 					      &del_size,
1265 					      max_reiserfs_offset(inode));
1266 
1267 		RFALSE(mode != M_DELETE, "PAP-5320: mode must be M_DELETE");
1268 
1269 		copy_item_head(&s_ih, tp_item_head(path));
1270 		s_del_balance.insert_size[0] = del_size;
1271 
1272 		ret_value = fix_nodes(M_DELETE, &s_del_balance, NULL, NULL);
1273 		if (ret_value != REPEAT_SEARCH)
1274 			break;
1275 
1276 		PROC_INFO_INC(sb, delete_item_restarted);
1277 
1278 		/* file system changed, repeat search */
1279 		ret_value =
1280 		    search_for_position_by_key(sb, item_key, path);
1281 		if (ret_value == IO_ERROR)
1282 			break;
1283 		if (ret_value == FILE_NOT_FOUND) {
1284 			reiserfs_warning(sb, "vs-5340",
1285 					 "no items of the file %K found",
1286 					 item_key);
1287 			break;
1288 		}
1289 	}			/* while (1) */
1290 
1291 	if (ret_value != CARRY_ON) {
1292 		unfix_nodes(&s_del_balance);
1293 		return 0;
1294 	}
1295 
1296 	/* reiserfs_delete_item returns item length when success */
1297 	ret_value = calc_deleted_bytes_number(&s_del_balance, M_DELETE);
1298 	q_ih = tp_item_head(path);
1299 	quota_cut_bytes = ih_item_len(q_ih);
1300 
1301 	/*
1302 	 * hack so the quota code doesn't have to guess if the file has a
1303 	 * tail.  On tail insert, we allocate quota for 1 unformatted node.
1304 	 * We test the offset because the tail might have been
1305 	 * split into multiple items, and we only want to decrement for
1306 	 * the unfm node once
1307 	 */
1308 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(q_ih)) {
1309 		if ((le_ih_k_offset(q_ih) & (sb->s_blocksize - 1)) == 1) {
1310 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1311 		} else {
1312 			quota_cut_bytes = 0;
1313 		}
1314 	}
1315 
1316 	if (un_bh) {
1317 		int off;
1318 		char *data;
1319 
1320 		/*
1321 		 * We are in direct2indirect conversion, so move tail contents
1322 		 * to the unformatted node
1323 		 */
1324 		/*
1325 		 * note, we do the copy before preparing the buffer because we
1326 		 * don't care about the contents of the unformatted node yet.
1327 		 * the only thing we really care about is the direct item's
1328 		 * data is in the unformatted node.
1329 		 *
1330 		 * Otherwise, we would have to call
1331 		 * reiserfs_prepare_for_journal on the unformatted node,
1332 		 * which might schedule, meaning we'd have to loop all the
1333 		 * way back up to the start of the while loop.
1334 		 *
1335 		 * The unformatted node must be dirtied later on.  We can't be
1336 		 * sure here if the entire tail has been deleted yet.
1337 		 *
1338 		 * un_bh is from the page cache (all unformatted nodes are
1339 		 * from the page cache) and might be a highmem page.  So, we
1340 		 * can't use un_bh->b_data.
1341 		 * -clm
1342 		 */
1343 
1344 		data = kmap_atomic(un_bh->b_page);
1345 		off = ((le_ih_k_offset(&s_ih) - 1) & (PAGE_SIZE - 1));
1346 		memcpy(data + off,
1347 		       ih_item_body(PATH_PLAST_BUFFER(path), &s_ih),
1348 		       ret_value);
1349 		kunmap_atomic(data);
1350 	}
1351 
1352 	/* Perform balancing after all resources have been collected at once. */
1353 	do_balance(&s_del_balance, NULL, NULL, M_DELETE);
1354 
1355 #ifdef REISERQUOTA_DEBUG
1356 	reiserfs_debug(sb, REISERFS_DEBUG_CODE,
1357 		       "reiserquota delete_item(): freeing %u, id=%u type=%c",
1358 		       quota_cut_bytes, inode->i_uid, head2type(&s_ih));
1359 #endif
1360 	depth = reiserfs_write_unlock_nested(inode->i_sb);
1361 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1362 	reiserfs_write_lock_nested(inode->i_sb, depth);
1363 
1364 	/* Return deleted body length */
1365 	return ret_value;
1366 }
1367 
1368 /*
1369  * Summary Of Mechanisms For Handling Collisions Between Processes:
1370  *
1371  *  deletion of the body of the object is performed by iput(), with the
1372  *  result that if multiple processes are operating on a file, the
1373  *  deletion of the body of the file is deferred until the last process
1374  *  that has an open inode performs its iput().
1375  *
1376  *  writes and truncates are protected from collisions by use of
1377  *  semaphores.
1378  *
1379  *  creates, linking, and mknod are protected from collisions with other
1380  *  processes by making the reiserfs_add_entry() the last step in the
1381  *  creation, and then rolling back all changes if there was a collision.
1382  *  - Hans
1383 */
1384 
1385 /* this deletes item which never gets split */
1386 void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
1387 				struct inode *inode, struct reiserfs_key *key)
1388 {
1389 	struct super_block *sb = th->t_super;
1390 	struct tree_balance tb;
1391 	INITIALIZE_PATH(path);
1392 	int item_len = 0;
1393 	int tb_init = 0;
1394 	struct cpu_key cpu_key;
1395 	int retval;
1396 	int quota_cut_bytes = 0;
1397 
1398 	BUG_ON(!th->t_trans_id);
1399 
1400 	le_key2cpu_key(&cpu_key, key);
1401 
1402 	while (1) {
1403 		retval = search_item(th->t_super, &cpu_key, &path);
1404 		if (retval == IO_ERROR) {
1405 			reiserfs_error(th->t_super, "vs-5350",
1406 				       "i/o failure occurred trying "
1407 				       "to delete %K", &cpu_key);
1408 			break;
1409 		}
1410 		if (retval != ITEM_FOUND) {
1411 			pathrelse(&path);
1412 			/*
1413 			 * No need for a warning, if there is just no free
1414 			 * space to insert '..' item into the
1415 			 * newly-created subdir
1416 			 */
1417 			if (!
1418 			    ((unsigned long long)
1419 			     GET_HASH_VALUE(le_key_k_offset
1420 					    (le_key_version(key), key)) == 0
1421 			     && (unsigned long long)
1422 			     GET_GENERATION_NUMBER(le_key_k_offset
1423 						   (le_key_version(key),
1424 						    key)) == 1))
1425 				reiserfs_warning(th->t_super, "vs-5355",
1426 						 "%k not found", key);
1427 			break;
1428 		}
1429 		if (!tb_init) {
1430 			tb_init = 1;
1431 			item_len = ih_item_len(tp_item_head(&path));
1432 			init_tb_struct(th, &tb, th->t_super, &path,
1433 				       -(IH_SIZE + item_len));
1434 		}
1435 		quota_cut_bytes = ih_item_len(tp_item_head(&path));
1436 
1437 		retval = fix_nodes(M_DELETE, &tb, NULL, NULL);
1438 		if (retval == REPEAT_SEARCH) {
1439 			PROC_INFO_INC(th->t_super, delete_solid_item_restarted);
1440 			continue;
1441 		}
1442 
1443 		if (retval == CARRY_ON) {
1444 			do_balance(&tb, NULL, NULL, M_DELETE);
1445 			/*
1446 			 * Should we count quota for item? (we don't
1447 			 * count quotas for save-links)
1448 			 */
1449 			if (inode) {
1450 				int depth;
1451 #ifdef REISERQUOTA_DEBUG
1452 				reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
1453 					       "reiserquota delete_solid_item(): freeing %u id=%u type=%c",
1454 					       quota_cut_bytes, inode->i_uid,
1455 					       key2type(key));
1456 #endif
1457 				depth = reiserfs_write_unlock_nested(sb);
1458 				dquot_free_space_nodirty(inode,
1459 							 quota_cut_bytes);
1460 				reiserfs_write_lock_nested(sb, depth);
1461 			}
1462 			break;
1463 		}
1464 
1465 		/* IO_ERROR, NO_DISK_SPACE, etc */
1466 		reiserfs_warning(th->t_super, "vs-5360",
1467 				 "could not delete %K due to fix_nodes failure",
1468 				 &cpu_key);
1469 		unfix_nodes(&tb);
1470 		break;
1471 	}
1472 
1473 	reiserfs_check_path(&path);
1474 }
1475 
1476 int reiserfs_delete_object(struct reiserfs_transaction_handle *th,
1477 			   struct inode *inode)
1478 {
1479 	int err;
1480 	inode->i_size = 0;
1481 	BUG_ON(!th->t_trans_id);
1482 
1483 	/* for directory this deletes item containing "." and ".." */
1484 	err =
1485 	    reiserfs_do_truncate(th, inode, NULL, 0 /*no timestamp updates */ );
1486 	if (err)
1487 		return err;
1488 
1489 #if defined( USE_INODE_GENERATION_COUNTER )
1490 	if (!old_format_only(th->t_super)) {
1491 		__le32 *inode_generation;
1492 
1493 		inode_generation =
1494 		    &REISERFS_SB(th->t_super)->s_rs->s_inode_generation;
1495 		le32_add_cpu(inode_generation, 1);
1496 	}
1497 /* USE_INODE_GENERATION_COUNTER */
1498 #endif
1499 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1500 
1501 	return err;
1502 }
1503 
1504 static void unmap_buffers(struct page *page, loff_t pos)
1505 {
1506 	struct buffer_head *bh;
1507 	struct buffer_head *head;
1508 	struct buffer_head *next;
1509 	unsigned long tail_index;
1510 	unsigned long cur_index;
1511 
1512 	if (page) {
1513 		if (page_has_buffers(page)) {
1514 			tail_index = pos & (PAGE_SIZE - 1);
1515 			cur_index = 0;
1516 			head = page_buffers(page);
1517 			bh = head;
1518 			do {
1519 				next = bh->b_this_page;
1520 
1521 				/*
1522 				 * we want to unmap the buffers that contain
1523 				 * the tail, and all the buffers after it
1524 				 * (since the tail must be at the end of the
1525 				 * file).  We don't want to unmap file data
1526 				 * before the tail, since it might be dirty
1527 				 * and waiting to reach disk
1528 				 */
1529 				cur_index += bh->b_size;
1530 				if (cur_index > tail_index) {
1531 					reiserfs_unmap_buffer(bh);
1532 				}
1533 				bh = next;
1534 			} while (bh != head);
1535 		}
1536 	}
1537 }
1538 
1539 static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
1540 				    struct inode *inode,
1541 				    struct page *page,
1542 				    struct treepath *path,
1543 				    const struct cpu_key *item_key,
1544 				    loff_t new_file_size, char *mode)
1545 {
1546 	struct super_block *sb = inode->i_sb;
1547 	int block_size = sb->s_blocksize;
1548 	int cut_bytes;
1549 	BUG_ON(!th->t_trans_id);
1550 	BUG_ON(new_file_size != inode->i_size);
1551 
1552 	/*
1553 	 * the page being sent in could be NULL if there was an i/o error
1554 	 * reading in the last block.  The user will hit problems trying to
1555 	 * read the file, but for now we just skip the indirect2direct
1556 	 */
1557 	if (atomic_read(&inode->i_count) > 1 ||
1558 	    !tail_has_to_be_packed(inode) ||
1559 	    !page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
1560 		/* leave tail in an unformatted node */
1561 		*mode = M_SKIP_BALANCING;
1562 		cut_bytes =
1563 		    block_size - (new_file_size & (block_size - 1));
1564 		pathrelse(path);
1565 		return cut_bytes;
1566 	}
1567 
1568 	/* Perform the conversion to a direct_item. */
1569 	return indirect2direct(th, inode, page, path, item_key,
1570 			       new_file_size, mode);
1571 }
1572 
1573 /*
1574  * we did indirect_to_direct conversion. And we have inserted direct
1575  * item successesfully, but there were no disk space to cut unfm
1576  * pointer being converted. Therefore we have to delete inserted
1577  * direct item(s)
1578  */
1579 static void indirect_to_direct_roll_back(struct reiserfs_transaction_handle *th,
1580 					 struct inode *inode, struct treepath *path)
1581 {
1582 	struct cpu_key tail_key;
1583 	int tail_len;
1584 	int removed;
1585 	BUG_ON(!th->t_trans_id);
1586 
1587 	make_cpu_key(&tail_key, inode, inode->i_size + 1, TYPE_DIRECT, 4);
1588 	tail_key.key_length = 4;
1589 
1590 	tail_len =
1591 	    (cpu_key_k_offset(&tail_key) & (inode->i_sb->s_blocksize - 1)) - 1;
1592 	while (tail_len) {
1593 		/* look for the last byte of the tail */
1594 		if (search_for_position_by_key(inode->i_sb, &tail_key, path) ==
1595 		    POSITION_NOT_FOUND)
1596 			reiserfs_panic(inode->i_sb, "vs-5615",
1597 				       "found invalid item");
1598 		RFALSE(path->pos_in_item !=
1599 		       ih_item_len(tp_item_head(path)) - 1,
1600 		       "vs-5616: appended bytes found");
1601 		PATH_LAST_POSITION(path)--;
1602 
1603 		removed =
1604 		    reiserfs_delete_item(th, path, &tail_key, inode,
1605 					 NULL /*unbh not needed */ );
1606 		RFALSE(removed <= 0
1607 		       || removed > tail_len,
1608 		       "vs-5617: there was tail %d bytes, removed item length %d bytes",
1609 		       tail_len, removed);
1610 		tail_len -= removed;
1611 		set_cpu_key_k_offset(&tail_key,
1612 				     cpu_key_k_offset(&tail_key) - removed);
1613 	}
1614 	reiserfs_warning(inode->i_sb, "reiserfs-5091", "indirect_to_direct "
1615 			 "conversion has been rolled back due to "
1616 			 "lack of disk space");
1617 	mark_inode_dirty(inode);
1618 }
1619 
1620 /* (Truncate or cut entry) or delete object item. Returns < 0 on failure */
1621 int reiserfs_cut_from_item(struct reiserfs_transaction_handle *th,
1622 			   struct treepath *path,
1623 			   struct cpu_key *item_key,
1624 			   struct inode *inode,
1625 			   struct page *page, loff_t new_file_size)
1626 {
1627 	struct super_block *sb = inode->i_sb;
1628 	/*
1629 	 * Every function which is going to call do_balance must first
1630 	 * create a tree_balance structure.  Then it must fill up this
1631 	 * structure by using the init_tb_struct and fix_nodes functions.
1632 	 * After that we can make tree balancing.
1633 	 */
1634 	struct tree_balance s_cut_balance;
1635 	struct item_head *p_le_ih;
1636 	int cut_size = 0;	/* Amount to be cut. */
1637 	int ret_value = CARRY_ON;
1638 	int removed = 0;	/* Number of the removed unformatted nodes. */
1639 	int is_inode_locked = 0;
1640 	char mode;		/* Mode of the balance. */
1641 	int retval2 = -1;
1642 	int quota_cut_bytes;
1643 	loff_t tail_pos = 0;
1644 	int depth;
1645 
1646 	BUG_ON(!th->t_trans_id);
1647 
1648 	init_tb_struct(th, &s_cut_balance, inode->i_sb, path,
1649 		       cut_size);
1650 
1651 	/*
1652 	 * Repeat this loop until we either cut the item without needing
1653 	 * to balance, or we fix_nodes without schedule occurring
1654 	 */
1655 	while (1) {
1656 		/*
1657 		 * Determine the balance mode, position of the first byte to
1658 		 * be cut, and size to be cut.  In case of the indirect item
1659 		 * free unformatted nodes which are pointed to by the cut
1660 		 * pointers.
1661 		 */
1662 
1663 		mode =
1664 		    prepare_for_delete_or_cut(th, inode, path,
1665 					      item_key, &removed,
1666 					      &cut_size, new_file_size);
1667 		if (mode == M_CONVERT) {
1668 			/*
1669 			 * convert last unformatted node to direct item or
1670 			 * leave tail in the unformatted node
1671 			 */
1672 			RFALSE(ret_value != CARRY_ON,
1673 			       "PAP-5570: can not convert twice");
1674 
1675 			ret_value =
1676 			    maybe_indirect_to_direct(th, inode, page,
1677 						     path, item_key,
1678 						     new_file_size, &mode);
1679 			if (mode == M_SKIP_BALANCING)
1680 				/* tail has been left in the unformatted node */
1681 				return ret_value;
1682 
1683 			is_inode_locked = 1;
1684 
1685 			/*
1686 			 * removing of last unformatted node will
1687 			 * change value we have to return to truncate.
1688 			 * Save it
1689 			 */
1690 			retval2 = ret_value;
1691 
1692 			/*
1693 			 * So, we have performed the first part of the
1694 			 * conversion:
1695 			 * inserting the new direct item.  Now we are
1696 			 * removing the last unformatted node pointer.
1697 			 * Set key to search for it.
1698 			 */
1699 			set_cpu_key_k_type(item_key, TYPE_INDIRECT);
1700 			item_key->key_length = 4;
1701 			new_file_size -=
1702 			    (new_file_size & (sb->s_blocksize - 1));
1703 			tail_pos = new_file_size;
1704 			set_cpu_key_k_offset(item_key, new_file_size + 1);
1705 			if (search_for_position_by_key
1706 			    (sb, item_key,
1707 			     path) == POSITION_NOT_FOUND) {
1708 				print_block(PATH_PLAST_BUFFER(path), 3,
1709 					    PATH_LAST_POSITION(path) - 1,
1710 					    PATH_LAST_POSITION(path) + 1);
1711 				reiserfs_panic(sb, "PAP-5580", "item to "
1712 					       "convert does not exist (%K)",
1713 					       item_key);
1714 			}
1715 			continue;
1716 		}
1717 		if (cut_size == 0) {
1718 			pathrelse(path);
1719 			return 0;
1720 		}
1721 
1722 		s_cut_balance.insert_size[0] = cut_size;
1723 
1724 		ret_value = fix_nodes(mode, &s_cut_balance, NULL, NULL);
1725 		if (ret_value != REPEAT_SEARCH)
1726 			break;
1727 
1728 		PROC_INFO_INC(sb, cut_from_item_restarted);
1729 
1730 		ret_value =
1731 		    search_for_position_by_key(sb, item_key, path);
1732 		if (ret_value == POSITION_FOUND)
1733 			continue;
1734 
1735 		reiserfs_warning(sb, "PAP-5610", "item %K not found",
1736 				 item_key);
1737 		unfix_nodes(&s_cut_balance);
1738 		return (ret_value == IO_ERROR) ? -EIO : -ENOENT;
1739 	}			/* while */
1740 
1741 	/* check fix_nodes results (IO_ERROR or NO_DISK_SPACE) */
1742 	if (ret_value != CARRY_ON) {
1743 		if (is_inode_locked) {
1744 			/*
1745 			 * FIXME: this seems to be not needed: we are always
1746 			 * able to cut item
1747 			 */
1748 			indirect_to_direct_roll_back(th, inode, path);
1749 		}
1750 		if (ret_value == NO_DISK_SPACE)
1751 			reiserfs_warning(sb, "reiserfs-5092",
1752 					 "NO_DISK_SPACE");
1753 		unfix_nodes(&s_cut_balance);
1754 		return -EIO;
1755 	}
1756 
1757 	/* go ahead and perform balancing */
1758 
1759 	RFALSE(mode == M_PASTE || mode == M_INSERT, "invalid mode");
1760 
1761 	/* Calculate number of bytes that need to be cut from the item. */
1762 	quota_cut_bytes =
1763 	    (mode ==
1764 	     M_DELETE) ? ih_item_len(tp_item_head(path)) : -s_cut_balance.
1765 	    insert_size[0];
1766 	if (retval2 == -1)
1767 		ret_value = calc_deleted_bytes_number(&s_cut_balance, mode);
1768 	else
1769 		ret_value = retval2;
1770 
1771 	/*
1772 	 * For direct items, we only change the quota when deleting the last
1773 	 * item.
1774 	 */
1775 	p_le_ih = tp_item_head(s_cut_balance.tb_path);
1776 	if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(p_le_ih)) {
1777 		if (mode == M_DELETE &&
1778 		    (le_ih_k_offset(p_le_ih) & (sb->s_blocksize - 1)) ==
1779 		    1) {
1780 			/* FIXME: this is to keep 3.5 happy */
1781 			REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
1782 			quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
1783 		} else {
1784 			quota_cut_bytes = 0;
1785 		}
1786 	}
1787 #ifdef CONFIG_REISERFS_CHECK
1788 	if (is_inode_locked) {
1789 		struct item_head *le_ih =
1790 		    tp_item_head(s_cut_balance.tb_path);
1791 		/*
1792 		 * we are going to complete indirect2direct conversion. Make
1793 		 * sure, that we exactly remove last unformatted node pointer
1794 		 * of the item
1795 		 */
1796 		if (!is_indirect_le_ih(le_ih))
1797 			reiserfs_panic(sb, "vs-5652",
1798 				       "item must be indirect %h", le_ih);
1799 
1800 		if (mode == M_DELETE && ih_item_len(le_ih) != UNFM_P_SIZE)
1801 			reiserfs_panic(sb, "vs-5653", "completing "
1802 				       "indirect2direct conversion indirect "
1803 				       "item %h being deleted must be of "
1804 				       "4 byte long", le_ih);
1805 
1806 		if (mode == M_CUT
1807 		    && s_cut_balance.insert_size[0] != -UNFM_P_SIZE) {
1808 			reiserfs_panic(sb, "vs-5654", "can not complete "
1809 				       "indirect2direct conversion of %h "
1810 				       "(CUT, insert_size==%d)",
1811 				       le_ih, s_cut_balance.insert_size[0]);
1812 		}
1813 		/*
1814 		 * it would be useful to make sure, that right neighboring
1815 		 * item is direct item of this file
1816 		 */
1817 	}
1818 #endif
1819 
1820 	do_balance(&s_cut_balance, NULL, NULL, mode);
1821 	if (is_inode_locked) {
1822 		/*
1823 		 * we've done an indirect->direct conversion.  when the
1824 		 * data block was freed, it was removed from the list of
1825 		 * blocks that must be flushed before the transaction
1826 		 * commits, make sure to unmap and invalidate it
1827 		 */
1828 		unmap_buffers(page, tail_pos);
1829 		REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
1830 	}
1831 #ifdef REISERQUOTA_DEBUG
1832 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
1833 		       "reiserquota cut_from_item(): freeing %u id=%u type=%c",
1834 		       quota_cut_bytes, inode->i_uid, '?');
1835 #endif
1836 	depth = reiserfs_write_unlock_nested(sb);
1837 	dquot_free_space_nodirty(inode, quota_cut_bytes);
1838 	reiserfs_write_lock_nested(sb, depth);
1839 	return ret_value;
1840 }
1841 
1842 static void truncate_directory(struct reiserfs_transaction_handle *th,
1843 			       struct inode *inode)
1844 {
1845 	BUG_ON(!th->t_trans_id);
1846 	if (inode->i_nlink)
1847 		reiserfs_error(inode->i_sb, "vs-5655", "link count != 0");
1848 
1849 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), DOT_OFFSET);
1850 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_DIRENTRY);
1851 	reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
1852 	reiserfs_update_sd(th, inode);
1853 	set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), SD_OFFSET);
1854 	set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_STAT_DATA);
1855 }
1856 
1857 /*
1858  * Truncate file to the new size. Note, this must be called with a
1859  * transaction already started
1860  */
1861 int reiserfs_do_truncate(struct reiserfs_transaction_handle *th,
1862 			 struct inode *inode,	/* ->i_size contains new size */
1863 			 struct page *page,	/* up to date for last block */
1864 			 /*
1865 			  * when it is called by file_release to convert
1866 			  * the tail - no timestamps should be updated
1867 			  */
1868 			 int update_timestamps
1869     )
1870 {
1871 	INITIALIZE_PATH(s_search_path);	/* Path to the current object item. */
1872 	struct item_head *p_le_ih;	/* Pointer to an item header. */
1873 
1874 	/* Key to search for a previous file item. */
1875 	struct cpu_key s_item_key;
1876 	loff_t file_size,	/* Old file size. */
1877 	 new_file_size;	/* New file size. */
1878 	int deleted;		/* Number of deleted or truncated bytes. */
1879 	int retval;
1880 	int err = 0;
1881 
1882 	BUG_ON(!th->t_trans_id);
1883 	if (!
1884 	    (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
1885 	     || S_ISLNK(inode->i_mode)))
1886 		return 0;
1887 
1888 	/* deletion of directory - no need to update timestamps */
1889 	if (S_ISDIR(inode->i_mode)) {
1890 		truncate_directory(th, inode);
1891 		return 0;
1892 	}
1893 
1894 	/* Get new file size. */
1895 	new_file_size = inode->i_size;
1896 
1897 	/* FIXME: note, that key type is unimportant here */
1898 	make_cpu_key(&s_item_key, inode, max_reiserfs_offset(inode),
1899 		     TYPE_DIRECT, 3);
1900 
1901 	retval =
1902 	    search_for_position_by_key(inode->i_sb, &s_item_key,
1903 				       &s_search_path);
1904 	if (retval == IO_ERROR) {
1905 		reiserfs_error(inode->i_sb, "vs-5657",
1906 			       "i/o failure occurred trying to truncate %K",
1907 			       &s_item_key);
1908 		err = -EIO;
1909 		goto out;
1910 	}
1911 	if (retval == POSITION_FOUND || retval == FILE_NOT_FOUND) {
1912 		reiserfs_error(inode->i_sb, "PAP-5660",
1913 			       "wrong result %d of search for %K", retval,
1914 			       &s_item_key);
1915 
1916 		err = -EIO;
1917 		goto out;
1918 	}
1919 
1920 	s_search_path.pos_in_item--;
1921 
1922 	/* Get real file size (total length of all file items) */
1923 	p_le_ih = tp_item_head(&s_search_path);
1924 	if (is_statdata_le_ih(p_le_ih))
1925 		file_size = 0;
1926 	else {
1927 		loff_t offset = le_ih_k_offset(p_le_ih);
1928 		int bytes =
1929 		    op_bytes_number(p_le_ih, inode->i_sb->s_blocksize);
1930 
1931 		/*
1932 		 * this may mismatch with real file size: if last direct item
1933 		 * had no padding zeros and last unformatted node had no free
1934 		 * space, this file would have this file size
1935 		 */
1936 		file_size = offset + bytes - 1;
1937 	}
1938 	/*
1939 	 * are we doing a full truncate or delete, if so
1940 	 * kick in the reada code
1941 	 */
1942 	if (new_file_size == 0)
1943 		s_search_path.reada = PATH_READA | PATH_READA_BACK;
1944 
1945 	if (file_size == 0 || file_size < new_file_size) {
1946 		goto update_and_out;
1947 	}
1948 
1949 	/* Update key to search for the last file item. */
1950 	set_cpu_key_k_offset(&s_item_key, file_size);
1951 
1952 	do {
1953 		/* Cut or delete file item. */
1954 		deleted =
1955 		    reiserfs_cut_from_item(th, &s_search_path, &s_item_key,
1956 					   inode, page, new_file_size);
1957 		if (deleted < 0) {
1958 			reiserfs_warning(inode->i_sb, "vs-5665",
1959 					 "reiserfs_cut_from_item failed");
1960 			reiserfs_check_path(&s_search_path);
1961 			return 0;
1962 		}
1963 
1964 		RFALSE(deleted > file_size,
1965 		       "PAP-5670: reiserfs_cut_from_item: too many bytes deleted: deleted %d, file_size %lu, item_key %K",
1966 		       deleted, file_size, &s_item_key);
1967 
1968 		/* Change key to search the last file item. */
1969 		file_size -= deleted;
1970 
1971 		set_cpu_key_k_offset(&s_item_key, file_size);
1972 
1973 		/*
1974 		 * While there are bytes to truncate and previous
1975 		 * file item is presented in the tree.
1976 		 */
1977 
1978 		/*
1979 		 * This loop could take a really long time, and could log
1980 		 * many more blocks than a transaction can hold.  So, we do
1981 		 * a polite journal end here, and if the transaction needs
1982 		 * ending, we make sure the file is consistent before ending
1983 		 * the current trans and starting a new one
1984 		 */
1985 		if (journal_transaction_should_end(th, 0) ||
1986 		    reiserfs_transaction_free_space(th) <= JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD) {
1987 			pathrelse(&s_search_path);
1988 
1989 			if (update_timestamps) {
1990 				inode->i_mtime = CURRENT_TIME_SEC;
1991 				inode->i_ctime = CURRENT_TIME_SEC;
1992 			}
1993 			reiserfs_update_sd(th, inode);
1994 
1995 			err = journal_end(th);
1996 			if (err)
1997 				goto out;
1998 			err = journal_begin(th, inode->i_sb,
1999 					    JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD + JOURNAL_PER_BALANCE_CNT * 4) ;
2000 			if (err)
2001 				goto out;
2002 			reiserfs_update_inode_transaction(inode);
2003 		}
2004 	} while (file_size > ROUND_UP(new_file_size) &&
2005 		 search_for_position_by_key(inode->i_sb, &s_item_key,
2006 					    &s_search_path) == POSITION_FOUND);
2007 
2008 	RFALSE(file_size > ROUND_UP(new_file_size),
2009 	       "PAP-5680: truncate did not finish: new_file_size %lld, current %lld, oid %d",
2010 	       new_file_size, file_size, s_item_key.on_disk_key.k_objectid);
2011 
2012 update_and_out:
2013 	if (update_timestamps) {
2014 		/* this is truncate, not file closing */
2015 		inode->i_mtime = CURRENT_TIME_SEC;
2016 		inode->i_ctime = CURRENT_TIME_SEC;
2017 	}
2018 	reiserfs_update_sd(th, inode);
2019 
2020 out:
2021 	pathrelse(&s_search_path);
2022 	return err;
2023 }
2024 
2025 #ifdef CONFIG_REISERFS_CHECK
2026 /* this makes sure, that we __append__, not overwrite or add holes */
2027 static void check_research_for_paste(struct treepath *path,
2028 				     const struct cpu_key *key)
2029 {
2030 	struct item_head *found_ih = tp_item_head(path);
2031 
2032 	if (is_direct_le_ih(found_ih)) {
2033 		if (le_ih_k_offset(found_ih) +
2034 		    op_bytes_number(found_ih,
2035 				    get_last_bh(path)->b_size) !=
2036 		    cpu_key_k_offset(key)
2037 		    || op_bytes_number(found_ih,
2038 				       get_last_bh(path)->b_size) !=
2039 		    pos_in_item(path))
2040 			reiserfs_panic(NULL, "PAP-5720", "found direct item "
2041 				       "%h or position (%d) does not match "
2042 				       "to key %K", found_ih,
2043 				       pos_in_item(path), key);
2044 	}
2045 	if (is_indirect_le_ih(found_ih)) {
2046 		if (le_ih_k_offset(found_ih) +
2047 		    op_bytes_number(found_ih,
2048 				    get_last_bh(path)->b_size) !=
2049 		    cpu_key_k_offset(key)
2050 		    || I_UNFM_NUM(found_ih) != pos_in_item(path)
2051 		    || get_ih_free_space(found_ih) != 0)
2052 			reiserfs_panic(NULL, "PAP-5730", "found indirect "
2053 				       "item (%h) or position (%d) does not "
2054 				       "match to key (%K)",
2055 				       found_ih, pos_in_item(path), key);
2056 	}
2057 }
2058 #endif				/* config reiserfs check */
2059 
2060 /*
2061  * Paste bytes to the existing item.
2062  * Returns bytes number pasted into the item.
2063  */
2064 int reiserfs_paste_into_item(struct reiserfs_transaction_handle *th,
2065 			     /* Path to the pasted item. */
2066 			     struct treepath *search_path,
2067 			     /* Key to search for the needed item. */
2068 			     const struct cpu_key *key,
2069 			     /* Inode item belongs to */
2070 			     struct inode *inode,
2071 			     /* Pointer to the bytes to paste. */
2072 			     const char *body,
2073 			     /* Size of pasted bytes. */
2074 			     int pasted_size)
2075 {
2076 	struct super_block *sb = inode->i_sb;
2077 	struct tree_balance s_paste_balance;
2078 	int retval;
2079 	int fs_gen;
2080 	int depth;
2081 
2082 	BUG_ON(!th->t_trans_id);
2083 
2084 	fs_gen = get_generation(inode->i_sb);
2085 
2086 #ifdef REISERQUOTA_DEBUG
2087 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2088 		       "reiserquota paste_into_item(): allocating %u id=%u type=%c",
2089 		       pasted_size, inode->i_uid,
2090 		       key2type(&key->on_disk_key));
2091 #endif
2092 
2093 	depth = reiserfs_write_unlock_nested(sb);
2094 	retval = dquot_alloc_space_nodirty(inode, pasted_size);
2095 	reiserfs_write_lock_nested(sb, depth);
2096 	if (retval) {
2097 		pathrelse(search_path);
2098 		return retval;
2099 	}
2100 	init_tb_struct(th, &s_paste_balance, th->t_super, search_path,
2101 		       pasted_size);
2102 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2103 	s_paste_balance.key = key->on_disk_key;
2104 #endif
2105 
2106 	/* DQUOT_* can schedule, must check before the fix_nodes */
2107 	if (fs_changed(fs_gen, inode->i_sb)) {
2108 		goto search_again;
2109 	}
2110 
2111 	while ((retval =
2112 		fix_nodes(M_PASTE, &s_paste_balance, NULL,
2113 			  body)) == REPEAT_SEARCH) {
2114 search_again:
2115 		/* file system changed while we were in the fix_nodes */
2116 		PROC_INFO_INC(th->t_super, paste_into_item_restarted);
2117 		retval =
2118 		    search_for_position_by_key(th->t_super, key,
2119 					       search_path);
2120 		if (retval == IO_ERROR) {
2121 			retval = -EIO;
2122 			goto error_out;
2123 		}
2124 		if (retval == POSITION_FOUND) {
2125 			reiserfs_warning(inode->i_sb, "PAP-5710",
2126 					 "entry or pasted byte (%K) exists",
2127 					 key);
2128 			retval = -EEXIST;
2129 			goto error_out;
2130 		}
2131 #ifdef CONFIG_REISERFS_CHECK
2132 		check_research_for_paste(search_path, key);
2133 #endif
2134 	}
2135 
2136 	/*
2137 	 * Perform balancing after all resources are collected by fix_nodes,
2138 	 * and accessing them will not risk triggering schedule.
2139 	 */
2140 	if (retval == CARRY_ON) {
2141 		do_balance(&s_paste_balance, NULL /*ih */ , body, M_PASTE);
2142 		return 0;
2143 	}
2144 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2145 error_out:
2146 	/* this also releases the path */
2147 	unfix_nodes(&s_paste_balance);
2148 #ifdef REISERQUOTA_DEBUG
2149 	reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2150 		       "reiserquota paste_into_item(): freeing %u id=%u type=%c",
2151 		       pasted_size, inode->i_uid,
2152 		       key2type(&key->on_disk_key));
2153 #endif
2154 	depth = reiserfs_write_unlock_nested(sb);
2155 	dquot_free_space_nodirty(inode, pasted_size);
2156 	reiserfs_write_lock_nested(sb, depth);
2157 	return retval;
2158 }
2159 
2160 /*
2161  * Insert new item into the buffer at the path.
2162  * th   - active transaction handle
2163  * path - path to the inserted item
2164  * ih   - pointer to the item header to insert
2165  * body - pointer to the bytes to insert
2166  */
2167 int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
2168 			 struct treepath *path, const struct cpu_key *key,
2169 			 struct item_head *ih, struct inode *inode,
2170 			 const char *body)
2171 {
2172 	struct tree_balance s_ins_balance;
2173 	int retval;
2174 	int fs_gen = 0;
2175 	int quota_bytes = 0;
2176 
2177 	BUG_ON(!th->t_trans_id);
2178 
2179 	if (inode) {		/* Do we count quotas for item? */
2180 		int depth;
2181 		fs_gen = get_generation(inode->i_sb);
2182 		quota_bytes = ih_item_len(ih);
2183 
2184 		/*
2185 		 * hack so the quota code doesn't have to guess
2186 		 * if the file has a tail, links are always tails,
2187 		 * so there's no guessing needed
2188 		 */
2189 		if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(ih))
2190 			quota_bytes = inode->i_sb->s_blocksize + UNFM_P_SIZE;
2191 #ifdef REISERQUOTA_DEBUG
2192 		reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
2193 			       "reiserquota insert_item(): allocating %u id=%u type=%c",
2194 			       quota_bytes, inode->i_uid, head2type(ih));
2195 #endif
2196 		/*
2197 		 * We can't dirty inode here. It would be immediately
2198 		 * written but appropriate stat item isn't inserted yet...
2199 		 */
2200 		depth = reiserfs_write_unlock_nested(inode->i_sb);
2201 		retval = dquot_alloc_space_nodirty(inode, quota_bytes);
2202 		reiserfs_write_lock_nested(inode->i_sb, depth);
2203 		if (retval) {
2204 			pathrelse(path);
2205 			return retval;
2206 		}
2207 	}
2208 	init_tb_struct(th, &s_ins_balance, th->t_super, path,
2209 		       IH_SIZE + ih_item_len(ih));
2210 #ifdef DISPLACE_NEW_PACKING_LOCALITIES
2211 	s_ins_balance.key = key->on_disk_key;
2212 #endif
2213 	/*
2214 	 * DQUOT_* can schedule, must check to be sure calling
2215 	 * fix_nodes is safe
2216 	 */
2217 	if (inode && fs_changed(fs_gen, inode->i_sb)) {
2218 		goto search_again;
2219 	}
2220 
2221 	while ((retval =
2222 		fix_nodes(M_INSERT, &s_ins_balance, ih,
2223 			  body)) == REPEAT_SEARCH) {
2224 search_again:
2225 		/* file system changed while we were in the fix_nodes */
2226 		PROC_INFO_INC(th->t_super, insert_item_restarted);
2227 		retval = search_item(th->t_super, key, path);
2228 		if (retval == IO_ERROR) {
2229 			retval = -EIO;
2230 			goto error_out;
2231 		}
2232 		if (retval == ITEM_FOUND) {
2233 			reiserfs_warning(th->t_super, "PAP-5760",
2234 					 "key %K already exists in the tree",
2235 					 key);
2236 			retval = -EEXIST;
2237 			goto error_out;
2238 		}
2239 	}
2240 
2241 	/* make balancing after all resources will be collected at a time */
2242 	if (retval == CARRY_ON) {
2243 		do_balance(&s_ins_balance, ih, body, M_INSERT);
2244 		return 0;
2245 	}
2246 
2247 	retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
2248 error_out:
2249 	/* also releases the path */
2250 	unfix_nodes(&s_ins_balance);
2251 #ifdef REISERQUOTA_DEBUG
2252 	reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
2253 		       "reiserquota insert_item(): freeing %u id=%u type=%c",
2254 		       quota_bytes, inode->i_uid, head2type(ih));
2255 #endif
2256 	if (inode) {
2257 		int depth = reiserfs_write_unlock_nested(inode->i_sb);
2258 		dquot_free_space_nodirty(inode, quota_bytes);
2259 		reiserfs_write_lock_nested(inode->i_sb, depth);
2260 	}
2261 	return retval;
2262 }
2263