xref: /linux/fs/jfs/jfs_xtree.c (revision 71d441ddb51941d9d8279bdc858f965711b85c14)
1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2005
3  *
4  *   This program is free software;  you can redistribute it and/or modify
5  *   it under the terms of the GNU General Public License as published by
6  *   the Free Software Foundation; either version 2 of the License, or
7  *   (at your option) any later version.
8  *
9  *   This program is distributed in the hope that it will be useful,
10  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
12  *   the GNU General Public License for more details.
13  *
14  *   You should have received a copy of the GNU General Public License
15  *   along with this program;  if not, write to the Free Software
16  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18 /*
19  *	jfs_xtree.c: extent allocation descriptor B+-tree manager
20  */
21 
22 #include <linux/fs.h>
23 #include <linux/quotaops.h>
24 #include "jfs_incore.h"
25 #include "jfs_filsys.h"
26 #include "jfs_metapage.h"
27 #include "jfs_dmap.h"
28 #include "jfs_dinode.h"
29 #include "jfs_superblock.h"
30 #include "jfs_debug.h"
31 
32 /*
33  * xtree local flag
34  */
35 #define XT_INSERT	0x00000001
36 
37 /*
38  *	xtree key/entry comparison: extent offset
39  *
40  * return:
41  *	-1: k < start of extent
42  *	 0: start_of_extent <= k <= end_of_extent
43  *	 1: k > end_of_extent
44  */
45 #define XT_CMP(CMP, K, X, OFFSET64)\
46 {\
47 	OFFSET64 = offsetXAD(X);\
48 	(CMP) = ((K) >= OFFSET64 + lengthXAD(X)) ? 1 :\
49 		((K) < OFFSET64) ? -1 : 0;\
50 }
51 
52 /* write a xad entry */
53 #define XT_PUTENTRY(XAD, FLAG, OFF, LEN, ADDR)\
54 {\
55 	(XAD)->flag = (FLAG);\
56 	XADoffset((XAD), (OFF));\
57 	XADlength((XAD), (LEN));\
58 	XADaddress((XAD), (ADDR));\
59 }
60 
61 #define XT_PAGE(IP, MP) BT_PAGE(IP, MP, xtpage_t, i_xtroot)
62 
63 /* get page buffer for specified block address */
64 /* ToDo: Replace this ugly macro with a function */
65 #define XT_GETPAGE(IP, BN, MP, SIZE, P, RC)\
66 {\
67 	BT_GETPAGE(IP, BN, MP, xtpage_t, SIZE, P, RC, i_xtroot)\
68 	if (!(RC))\
69 	{\
70 		if ((le16_to_cpu((P)->header.nextindex) < XTENTRYSTART) ||\
71 		    (le16_to_cpu((P)->header.nextindex) > le16_to_cpu((P)->header.maxentry)) ||\
72 		    (le16_to_cpu((P)->header.maxentry) > (((BN)==0)?XTROOTMAXSLOT:PSIZE>>L2XTSLOTSIZE)))\
73 		{\
74 			jfs_error((IP)->i_sb, "XT_GETPAGE: xtree page corrupt");\
75 			BT_PUTPAGE(MP);\
76 			MP = NULL;\
77 			RC = -EIO;\
78 		}\
79 	}\
80 }
81 
82 /* for consistency */
83 #define XT_PUTPAGE(MP) BT_PUTPAGE(MP)
84 
85 #define XT_GETSEARCH(IP, LEAF, BN, MP, P, INDEX) \
86 	BT_GETSEARCH(IP, LEAF, BN, MP, xtpage_t, P, INDEX, i_xtroot)
87 /* xtree entry parameter descriptor */
88 struct xtsplit {
89 	struct metapage *mp;
90 	s16 index;
91 	u8 flag;
92 	s64 off;
93 	s64 addr;
94 	int len;
95 	struct pxdlist *pxdlist;
96 };
97 
98 
99 /*
100  *	statistics
101  */
102 #ifdef CONFIG_JFS_STATISTICS
103 static struct {
104 	uint search;
105 	uint fastSearch;
106 	uint split;
107 } xtStat;
108 #endif
109 
110 
111 /*
112  * forward references
113  */
114 static int xtSearch(struct inode *ip, s64 xoff, s64 *next, int *cmpp,
115 		    struct btstack * btstack, int flag);
116 
117 static int xtSplitUp(tid_t tid,
118 		     struct inode *ip,
119 		     struct xtsplit * split, struct btstack * btstack);
120 
121 static int xtSplitPage(tid_t tid, struct inode *ip, struct xtsplit * split,
122 		       struct metapage ** rmpp, s64 * rbnp);
123 
124 static int xtSplitRoot(tid_t tid, struct inode *ip,
125 		       struct xtsplit * split, struct metapage ** rmpp);
126 
127 #ifdef _STILL_TO_PORT
128 static int xtDeleteUp(tid_t tid, struct inode *ip, struct metapage * fmp,
129 		      xtpage_t * fp, struct btstack * btstack);
130 
131 static int xtSearchNode(struct inode *ip,
132 			xad_t * xad,
133 			int *cmpp, struct btstack * btstack, int flag);
134 
135 static int xtRelink(tid_t tid, struct inode *ip, xtpage_t * fp);
136 #endif				/*  _STILL_TO_PORT */
137 
138 /*
139  *	xtLookup()
140  *
141  * function: map a single page into a physical extent;
142  */
143 int xtLookup(struct inode *ip, s64 lstart,
144 	     s64 llen, int *pflag, s64 * paddr, s32 * plen, int no_check)
145 {
146 	int rc = 0;
147 	struct btstack btstack;
148 	int cmp;
149 	s64 bn;
150 	struct metapage *mp;
151 	xtpage_t *p;
152 	int index;
153 	xad_t *xad;
154 	s64 next, size, xoff, xend;
155 	int xlen;
156 	s64 xaddr;
157 
158 	*paddr = 0;
159 	*plen = llen;
160 
161 	if (!no_check) {
162 		/* is lookup offset beyond eof ? */
163 		size = ((u64) ip->i_size + (JFS_SBI(ip->i_sb)->bsize - 1)) >>
164 		    JFS_SBI(ip->i_sb)->l2bsize;
165 		if (lstart >= size) {
166 			jfs_err("xtLookup: lstart (0x%lx) >= size (0x%lx)",
167 				(ulong) lstart, (ulong) size);
168 			return 0;
169 		}
170 	}
171 
172 	/*
173 	 * search for the xad entry covering the logical extent
174 	 */
175 //search:
176 	if ((rc = xtSearch(ip, lstart, &next, &cmp, &btstack, 0))) {
177 		jfs_err("xtLookup: xtSearch returned %d", rc);
178 		return rc;
179 	}
180 
181 	/*
182 	 *	compute the physical extent covering logical extent
183 	 *
184 	 * N.B. search may have failed (e.g., hole in sparse file),
185 	 * and returned the index of the next entry.
186 	 */
187 	/* retrieve search result */
188 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
189 
190 	/* is xad found covering start of logical extent ?
191 	 * lstart is a page start address,
192 	 * i.e., lstart cannot start in a hole;
193 	 */
194 	if (cmp) {
195 		if (next)
196 			*plen = min(next - lstart, llen);
197 		goto out;
198 	}
199 
200 	/*
201 	 * lxd covered by xad
202 	 */
203 	xad = &p->xad[index];
204 	xoff = offsetXAD(xad);
205 	xlen = lengthXAD(xad);
206 	xend = xoff + xlen;
207 	xaddr = addressXAD(xad);
208 
209 	/* initialize new pxd */
210 	*pflag = xad->flag;
211 	*paddr = xaddr + (lstart - xoff);
212 	/* a page must be fully covered by an xad */
213 	*plen = min(xend - lstart, llen);
214 
215       out:
216 	XT_PUTPAGE(mp);
217 
218 	return rc;
219 }
220 
221 
222 /*
223  *	xtLookupList()
224  *
225  * function: map a single logical extent into a list of physical extent;
226  *
227  * parameter:
228  *	struct inode	*ip,
229  *	struct lxdlist	*lxdlist,	lxd list (in)
230  *	struct xadlist	*xadlist,	xad list (in/out)
231  *	int		flag)
232  *
233  * coverage of lxd by xad under assumption of
234  * . lxd's are ordered and disjoint.
235  * . xad's are ordered and disjoint.
236  *
237  * return:
238  *	0:	success
239  *
240  * note: a page being written (even a single byte) is backed fully,
241  *	except the last page which is only backed with blocks
242  *	required to cover the last byte;
243  *	the extent backing a page is fully contained within an xad;
244  */
245 int xtLookupList(struct inode *ip, struct lxdlist * lxdlist,
246 		 struct xadlist * xadlist, int flag)
247 {
248 	int rc = 0;
249 	struct btstack btstack;
250 	int cmp;
251 	s64 bn;
252 	struct metapage *mp;
253 	xtpage_t *p;
254 	int index;
255 	lxd_t *lxd;
256 	xad_t *xad, *pxd;
257 	s64 size, lstart, lend, xstart, xend, pstart;
258 	s64 llen, xlen, plen;
259 	s64 xaddr, paddr;
260 	int nlxd, npxd, maxnpxd;
261 
262 	npxd = xadlist->nxad = 0;
263 	maxnpxd = xadlist->maxnxad;
264 	pxd = xadlist->xad;
265 
266 	nlxd = lxdlist->nlxd;
267 	lxd = lxdlist->lxd;
268 
269 	lstart = offsetLXD(lxd);
270 	llen = lengthLXD(lxd);
271 	lend = lstart + llen;
272 
273 	size = (ip->i_size + (JFS_SBI(ip->i_sb)->bsize - 1)) >>
274 	    JFS_SBI(ip->i_sb)->l2bsize;
275 
276 	/*
277 	 * search for the xad entry covering the logical extent
278 	 */
279       search:
280 	if (lstart >= size)
281 		return 0;
282 
283 	if ((rc = xtSearch(ip, lstart, NULL, &cmp, &btstack, 0)))
284 		return rc;
285 
286 	/*
287 	 *	compute the physical extent covering logical extent
288 	 *
289 	 * N.B. search may have failed (e.g., hole in sparse file),
290 	 * and returned the index of the next entry.
291 	 */
292 //map:
293 	/* retrieve search result */
294 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
295 
296 	/* is xad on the next sibling page ? */
297 	if (index == le16_to_cpu(p->header.nextindex)) {
298 		if (p->header.flag & BT_ROOT)
299 			goto mapend;
300 
301 		if ((bn = le64_to_cpu(p->header.next)) == 0)
302 			goto mapend;
303 
304 		XT_PUTPAGE(mp);
305 
306 		/* get next sibling page */
307 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
308 		if (rc)
309 			return rc;
310 
311 		index = XTENTRYSTART;
312 	}
313 
314 	xad = &p->xad[index];
315 
316 	/*
317 	 * is lxd covered by xad ?
318 	 */
319       compare:
320 	xstart = offsetXAD(xad);
321 	xlen = lengthXAD(xad);
322 	xend = xstart + xlen;
323 	xaddr = addressXAD(xad);
324 
325       compare1:
326 	if (xstart < lstart)
327 		goto compare2;
328 
329 	/* (lstart <= xstart) */
330 
331 	/* lxd is NOT covered by xad */
332 	if (lend <= xstart) {
333 		/*
334 		 * get next lxd
335 		 */
336 		if (--nlxd == 0)
337 			goto mapend;
338 		lxd++;
339 
340 		lstart = offsetLXD(lxd);
341 		llen = lengthLXD(lxd);
342 		lend = lstart + llen;
343 		if (lstart >= size)
344 			goto mapend;
345 
346 		/* compare with the current xad */
347 		goto compare1;
348 	}
349 	/* lxd is covered by xad */
350 	else {			/* (xstart < lend) */
351 
352 		/* initialize new pxd */
353 		pstart = xstart;
354 		plen = min(lend - xstart, xlen);
355 		paddr = xaddr;
356 
357 		goto cover;
358 	}
359 
360 	/* (xstart < lstart) */
361       compare2:
362 	/* lxd is covered by xad */
363 	if (lstart < xend) {
364 		/* initialize new pxd */
365 		pstart = lstart;
366 		plen = min(xend - lstart, llen);
367 		paddr = xaddr + (lstart - xstart);
368 
369 		goto cover;
370 	}
371 	/* lxd is NOT covered by xad */
372 	else {			/* (xend <= lstart) */
373 
374 		/*
375 		 * get next xad
376 		 *
377 		 * linear search next xad covering lxd on
378 		 * the current xad page, and then tree search
379 		 */
380 		if (index == le16_to_cpu(p->header.nextindex) - 1) {
381 			if (p->header.flag & BT_ROOT)
382 				goto mapend;
383 
384 			XT_PUTPAGE(mp);
385 			goto search;
386 		} else {
387 			index++;
388 			xad++;
389 
390 			/* compare with new xad */
391 			goto compare;
392 		}
393 	}
394 
395 	/*
396 	 * lxd is covered by xad and a new pxd has been initialized
397 	 * (lstart <= xstart < lend) or (xstart < lstart < xend)
398 	 */
399       cover:
400 	/* finalize pxd corresponding to current xad */
401 	XT_PUTENTRY(pxd, xad->flag, pstart, plen, paddr);
402 
403 	if (++npxd >= maxnpxd)
404 		goto mapend;
405 	pxd++;
406 
407 	/*
408 	 * lxd is fully covered by xad
409 	 */
410 	if (lend <= xend) {
411 		/*
412 		 * get next lxd
413 		 */
414 		if (--nlxd == 0)
415 			goto mapend;
416 		lxd++;
417 
418 		lstart = offsetLXD(lxd);
419 		llen = lengthLXD(lxd);
420 		lend = lstart + llen;
421 		if (lstart >= size)
422 			goto mapend;
423 
424 		/*
425 		 * test for old xad covering new lxd
426 		 * (old xstart < new lstart)
427 		 */
428 		goto compare2;
429 	}
430 	/*
431 	 * lxd is partially covered by xad
432 	 */
433 	else {			/* (xend < lend) */
434 
435 		/*
436 		 * get next xad
437 		 *
438 		 * linear search next xad covering lxd on
439 		 * the current xad page, and then next xad page search
440 		 */
441 		if (index == le16_to_cpu(p->header.nextindex) - 1) {
442 			if (p->header.flag & BT_ROOT)
443 				goto mapend;
444 
445 			if ((bn = le64_to_cpu(p->header.next)) == 0)
446 				goto mapend;
447 
448 			XT_PUTPAGE(mp);
449 
450 			/* get next sibling page */
451 			XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
452 			if (rc)
453 				return rc;
454 
455 			index = XTENTRYSTART;
456 			xad = &p->xad[index];
457 		} else {
458 			index++;
459 			xad++;
460 		}
461 
462 		/*
463 		 * test for new xad covering old lxd
464 		 * (old lstart < new xstart)
465 		 */
466 		goto compare;
467 	}
468 
469       mapend:
470 	xadlist->nxad = npxd;
471 
472 //out:
473 	XT_PUTPAGE(mp);
474 
475 	return rc;
476 }
477 
478 
479 /*
480  *	xtSearch()
481  *
482  * function:	search for the xad entry covering specified offset.
483  *
484  * parameters:
485  *	ip	- file object;
486  *	xoff	- extent offset;
487  *	nextp	- address of next extent (if any) for search miss
488  *	cmpp	- comparison result:
489  *	btstack - traverse stack;
490  *	flag	- search process flag (XT_INSERT);
491  *
492  * returns:
493  *	btstack contains (bn, index) of search path traversed to the entry.
494  *	*cmpp is set to result of comparison with the entry returned.
495  *	the page containing the entry is pinned at exit.
496  */
497 static int xtSearch(struct inode *ip, s64 xoff,	s64 *nextp,
498 		    int *cmpp, struct btstack * btstack, int flag)
499 {
500 	struct jfs_inode_info *jfs_ip = JFS_IP(ip);
501 	int rc = 0;
502 	int cmp = 1;		/* init for empty page */
503 	s64 bn;			/* block number */
504 	struct metapage *mp;	/* page buffer */
505 	xtpage_t *p;		/* page */
506 	xad_t *xad;
507 	int base, index, lim, btindex;
508 	struct btframe *btsp;
509 	int nsplit = 0;		/* number of pages to split */
510 	s64 t64;
511 	s64 next = 0;
512 
513 	INCREMENT(xtStat.search);
514 
515 	BT_CLR(btstack);
516 
517 	btstack->nsplit = 0;
518 
519 	/*
520 	 *	search down tree from root:
521 	 *
522 	 * between two consecutive entries of <Ki, Pi> and <Kj, Pj> of
523 	 * internal page, child page Pi contains entry with k, Ki <= K < Kj.
524 	 *
525 	 * if entry with search key K is not found
526 	 * internal page search find the entry with largest key Ki
527 	 * less than K which point to the child page to search;
528 	 * leaf page search find the entry with smallest key Kj
529 	 * greater than K so that the returned index is the position of
530 	 * the entry to be shifted right for insertion of new entry.
531 	 * for empty tree, search key is greater than any key of the tree.
532 	 *
533 	 * by convention, root bn = 0.
534 	 */
535 	for (bn = 0;;) {
536 		/* get/pin the page to search */
537 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
538 		if (rc)
539 			return rc;
540 
541 		/* try sequential access heuristics with the previous
542 		 * access entry in target leaf page:
543 		 * once search narrowed down into the target leaf,
544 		 * key must either match an entry in the leaf or
545 		 * key entry does not exist in the tree;
546 		 */
547 //fastSearch:
548 		if ((jfs_ip->btorder & BT_SEQUENTIAL) &&
549 		    (p->header.flag & BT_LEAF) &&
550 		    (index = jfs_ip->btindex) <
551 		    le16_to_cpu(p->header.nextindex)) {
552 			xad = &p->xad[index];
553 			t64 = offsetXAD(xad);
554 			if (xoff < t64 + lengthXAD(xad)) {
555 				if (xoff >= t64) {
556 					*cmpp = 0;
557 					goto out;
558 				}
559 
560 				/* stop sequential access heuristics */
561 				goto binarySearch;
562 			} else {	/* (t64 + lengthXAD(xad)) <= xoff */
563 
564 				/* try next sequential entry */
565 				index++;
566 				if (index <
567 				    le16_to_cpu(p->header.nextindex)) {
568 					xad++;
569 					t64 = offsetXAD(xad);
570 					if (xoff < t64 + lengthXAD(xad)) {
571 						if (xoff >= t64) {
572 							*cmpp = 0;
573 							goto out;
574 						}
575 
576 						/* miss: key falls between
577 						 * previous and this entry
578 						 */
579 						*cmpp = 1;
580 						next = t64;
581 						goto out;
582 					}
583 
584 					/* (xoff >= t64 + lengthXAD(xad));
585 					 * matching entry may be further out:
586 					 * stop heuristic search
587 					 */
588 					/* stop sequential access heuristics */
589 					goto binarySearch;
590 				}
591 
592 				/* (index == p->header.nextindex);
593 				 * miss: key entry does not exist in
594 				 * the target leaf/tree
595 				 */
596 				*cmpp = 1;
597 				goto out;
598 			}
599 
600 			/*
601 			 * if hit, return index of the entry found, and
602 			 * if miss, where new entry with search key is
603 			 * to be inserted;
604 			 */
605 		      out:
606 			/* compute number of pages to split */
607 			if (flag & XT_INSERT) {
608 				if (p->header.nextindex ==	/* little-endian */
609 				    p->header.maxentry)
610 					nsplit++;
611 				else
612 					nsplit = 0;
613 				btstack->nsplit = nsplit;
614 			}
615 
616 			/* save search result */
617 			btsp = btstack->top;
618 			btsp->bn = bn;
619 			btsp->index = index;
620 			btsp->mp = mp;
621 
622 			/* update sequential access heuristics */
623 			jfs_ip->btindex = index;
624 
625 			if (nextp)
626 				*nextp = next;
627 
628 			INCREMENT(xtStat.fastSearch);
629 			return 0;
630 		}
631 
632 		/* well, ... full search now */
633 	      binarySearch:
634 		lim = le16_to_cpu(p->header.nextindex) - XTENTRYSTART;
635 
636 		/*
637 		 * binary search with search key K on the current page
638 		 */
639 		for (base = XTENTRYSTART; lim; lim >>= 1) {
640 			index = base + (lim >> 1);
641 
642 			XT_CMP(cmp, xoff, &p->xad[index], t64);
643 			if (cmp == 0) {
644 				/*
645 				 *	search hit
646 				 */
647 				/* search hit - leaf page:
648 				 * return the entry found
649 				 */
650 				if (p->header.flag & BT_LEAF) {
651 					*cmpp = cmp;
652 
653 					/* compute number of pages to split */
654 					if (flag & XT_INSERT) {
655 						if (p->header.nextindex ==
656 						    p->header.maxentry)
657 							nsplit++;
658 						else
659 							nsplit = 0;
660 						btstack->nsplit = nsplit;
661 					}
662 
663 					/* save search result */
664 					btsp = btstack->top;
665 					btsp->bn = bn;
666 					btsp->index = index;
667 					btsp->mp = mp;
668 
669 					/* init sequential access heuristics */
670 					btindex = jfs_ip->btindex;
671 					if (index == btindex ||
672 					    index == btindex + 1)
673 						jfs_ip->btorder = BT_SEQUENTIAL;
674 					else
675 						jfs_ip->btorder = BT_RANDOM;
676 					jfs_ip->btindex = index;
677 
678 					return 0;
679 				}
680 				/* search hit - internal page:
681 				 * descend/search its child page
682 				 */
683 				if (index < le16_to_cpu(p->header.nextindex)-1)
684 					next = offsetXAD(&p->xad[index + 1]);
685 				goto next;
686 			}
687 
688 			if (cmp > 0) {
689 				base = index + 1;
690 				--lim;
691 			}
692 		}
693 
694 		/*
695 		 *	search miss
696 		 *
697 		 * base is the smallest index with key (Kj) greater than
698 		 * search key (K) and may be zero or maxentry index.
699 		 */
700 		if (base < le16_to_cpu(p->header.nextindex))
701 			next = offsetXAD(&p->xad[base]);
702 		/*
703 		 * search miss - leaf page:
704 		 *
705 		 * return location of entry (base) where new entry with
706 		 * search key K is to be inserted.
707 		 */
708 		if (p->header.flag & BT_LEAF) {
709 			*cmpp = cmp;
710 
711 			/* compute number of pages to split */
712 			if (flag & XT_INSERT) {
713 				if (p->header.nextindex ==
714 				    p->header.maxentry)
715 					nsplit++;
716 				else
717 					nsplit = 0;
718 				btstack->nsplit = nsplit;
719 			}
720 
721 			/* save search result */
722 			btsp = btstack->top;
723 			btsp->bn = bn;
724 			btsp->index = base;
725 			btsp->mp = mp;
726 
727 			/* init sequential access heuristics */
728 			btindex = jfs_ip->btindex;
729 			if (base == btindex || base == btindex + 1)
730 				jfs_ip->btorder = BT_SEQUENTIAL;
731 			else
732 				jfs_ip->btorder = BT_RANDOM;
733 			jfs_ip->btindex = base;
734 
735 			if (nextp)
736 				*nextp = next;
737 
738 			return 0;
739 		}
740 
741 		/*
742 		 * search miss - non-leaf page:
743 		 *
744 		 * if base is non-zero, decrement base by one to get the parent
745 		 * entry of the child page to search.
746 		 */
747 		index = base ? base - 1 : base;
748 
749 		/*
750 		 * go down to child page
751 		 */
752 	      next:
753 		/* update number of pages to split */
754 		if (p->header.nextindex == p->header.maxentry)
755 			nsplit++;
756 		else
757 			nsplit = 0;
758 
759 		/* push (bn, index) of the parent page/entry */
760 		if (BT_STACK_FULL(btstack)) {
761 			jfs_error(ip->i_sb, "stack overrun in xtSearch!");
762 			XT_PUTPAGE(mp);
763 			return -EIO;
764 		}
765 		BT_PUSH(btstack, bn, index);
766 
767 		/* get the child page block number */
768 		bn = addressXAD(&p->xad[index]);
769 
770 		/* unpin the parent page */
771 		XT_PUTPAGE(mp);
772 	}
773 }
774 
775 /*
776  *	xtInsert()
777  *
778  * function:
779  *
780  * parameter:
781  *	tid	- transaction id;
782  *	ip	- file object;
783  *	xflag	- extent flag (XAD_NOTRECORDED):
784  *	xoff	- extent offset;
785  *	xlen	- extent length;
786  *	xaddrp	- extent address pointer (in/out):
787  *		if (*xaddrp)
788  *			caller allocated data extent at *xaddrp;
789  *		else
790  *			allocate data extent and return its xaddr;
791  *	flag	-
792  *
793  * return:
794  */
795 int xtInsert(tid_t tid,		/* transaction id */
796 	     struct inode *ip, int xflag, s64 xoff, s32 xlen, s64 * xaddrp,
797 	     int flag)
798 {
799 	int rc = 0;
800 	s64 xaddr, hint;
801 	struct metapage *mp;	/* meta-page buffer */
802 	xtpage_t *p;		/* base B+-tree index page */
803 	s64 bn;
804 	int index, nextindex;
805 	struct btstack btstack;	/* traverse stack */
806 	struct xtsplit split;	/* split information */
807 	xad_t *xad;
808 	int cmp;
809 	s64 next;
810 	struct tlock *tlck;
811 	struct xtlock *xtlck;
812 
813 	jfs_info("xtInsert: nxoff:0x%lx nxlen:0x%x", (ulong) xoff, xlen);
814 
815 	/*
816 	 *	search for the entry location at which to insert:
817 	 *
818 	 * xtFastSearch() and xtSearch() both returns (leaf page
819 	 * pinned, index at which to insert).
820 	 * n.b. xtSearch() may return index of maxentry of
821 	 * the full page.
822 	 */
823 	if ((rc = xtSearch(ip, xoff, &next, &cmp, &btstack, XT_INSERT)))
824 		return rc;
825 
826 	/* retrieve search result */
827 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
828 
829 	/* This test must follow XT_GETSEARCH since mp must be valid if
830 	 * we branch to out: */
831 	if ((cmp == 0) || (next && (xlen > next - xoff))) {
832 		rc = -EEXIST;
833 		goto out;
834 	}
835 
836 	/*
837 	 * allocate data extent requested
838 	 *
839 	 * allocation hint: last xad
840 	 */
841 	if ((xaddr = *xaddrp) == 0) {
842 		if (index > XTENTRYSTART) {
843 			xad = &p->xad[index - 1];
844 			hint = addressXAD(xad) + lengthXAD(xad) - 1;
845 		} else
846 			hint = 0;
847 		if ((rc = DQUOT_ALLOC_BLOCK(ip, xlen)))
848 			goto out;
849 		if ((rc = dbAlloc(ip, hint, (s64) xlen, &xaddr))) {
850 			DQUOT_FREE_BLOCK(ip, xlen);
851 			goto out;
852 		}
853 	}
854 
855 	/*
856 	 *	insert entry for new extent
857 	 */
858 	xflag |= XAD_NEW;
859 
860 	/*
861 	 *	if the leaf page is full, split the page and
862 	 *	propagate up the router entry for the new page from split
863 	 *
864 	 * The xtSplitUp() will insert the entry and unpin the leaf page.
865 	 */
866 	nextindex = le16_to_cpu(p->header.nextindex);
867 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
868 		split.mp = mp;
869 		split.index = index;
870 		split.flag = xflag;
871 		split.off = xoff;
872 		split.len = xlen;
873 		split.addr = xaddr;
874 		split.pxdlist = NULL;
875 		if ((rc = xtSplitUp(tid, ip, &split, &btstack))) {
876 			/* undo data extent allocation */
877 			if (*xaddrp == 0) {
878 				dbFree(ip, xaddr, (s64) xlen);
879 				DQUOT_FREE_BLOCK(ip, xlen);
880 			}
881 			return rc;
882 		}
883 
884 		*xaddrp = xaddr;
885 		return 0;
886 	}
887 
888 	/*
889 	 *	insert the new entry into the leaf page
890 	 */
891 	/*
892 	 * acquire a transaction lock on the leaf page;
893 	 *
894 	 * action: xad insertion/extension;
895 	 */
896 	BT_MARK_DIRTY(mp, ip);
897 
898 	/* if insert into middle, shift right remaining entries. */
899 	if (index < nextindex)
900 		memmove(&p->xad[index + 1], &p->xad[index],
901 			(nextindex - index) * sizeof(xad_t));
902 
903 	/* insert the new entry: mark the entry NEW */
904 	xad = &p->xad[index];
905 	XT_PUTENTRY(xad, xflag, xoff, xlen, xaddr);
906 
907 	/* advance next available entry index */
908 	p->header.nextindex =
909 	    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
910 
911 	/* Don't log it if there are no links to the file */
912 	if (!test_cflag(COMMIT_Nolink, ip)) {
913 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
914 		xtlck = (struct xtlock *) & tlck->lock;
915 		xtlck->lwm.offset =
916 		    (xtlck->lwm.offset) ? min(index,
917 					      (int)xtlck->lwm.offset) : index;
918 		xtlck->lwm.length =
919 		    le16_to_cpu(p->header.nextindex) - xtlck->lwm.offset;
920 	}
921 
922 	*xaddrp = xaddr;
923 
924       out:
925 	/* unpin the leaf page */
926 	XT_PUTPAGE(mp);
927 
928 	return rc;
929 }
930 
931 
932 /*
933  *	xtSplitUp()
934  *
935  * function:
936  *	split full pages as propagating insertion up the tree
937  *
938  * parameter:
939  *	tid	- transaction id;
940  *	ip	- file object;
941  *	split	- entry parameter descriptor;
942  *	btstack - traverse stack from xtSearch()
943  *
944  * return:
945  */
946 static int
947 xtSplitUp(tid_t tid,
948 	  struct inode *ip, struct xtsplit * split, struct btstack * btstack)
949 {
950 	int rc = 0;
951 	struct metapage *smp;
952 	xtpage_t *sp;		/* split page */
953 	struct metapage *rmp;
954 	s64 rbn;		/* new right page block number */
955 	struct metapage *rcmp;
956 	xtpage_t *rcp;		/* right child page */
957 	s64 rcbn;		/* right child page block number */
958 	int skip;		/* index of entry of insertion */
959 	int nextindex;		/* next available entry index of p */
960 	struct btframe *parent;	/* parent page entry on traverse stack */
961 	xad_t *xad;
962 	s64 xaddr;
963 	int xlen;
964 	int nsplit;		/* number of pages split */
965 	struct pxdlist pxdlist;
966 	pxd_t *pxd;
967 	struct tlock *tlck;
968 	struct xtlock *xtlck;
969 
970 	smp = split->mp;
971 	sp = XT_PAGE(ip, smp);
972 
973 	/* is inode xtree root extension/inline EA area free ? */
974 	if ((sp->header.flag & BT_ROOT) && (!S_ISDIR(ip->i_mode)) &&
975 	    (le16_to_cpu(sp->header.maxentry) < XTROOTMAXSLOT) &&
976 	    (JFS_IP(ip)->mode2 & INLINEEA)) {
977 		sp->header.maxentry = cpu_to_le16(XTROOTMAXSLOT);
978 		JFS_IP(ip)->mode2 &= ~INLINEEA;
979 
980 		BT_MARK_DIRTY(smp, ip);
981 		/*
982 		 * acquire a transaction lock on the leaf page;
983 		 *
984 		 * action: xad insertion/extension;
985 		 */
986 
987 		/* if insert into middle, shift right remaining entries. */
988 		skip = split->index;
989 		nextindex = le16_to_cpu(sp->header.nextindex);
990 		if (skip < nextindex)
991 			memmove(&sp->xad[skip + 1], &sp->xad[skip],
992 				(nextindex - skip) * sizeof(xad_t));
993 
994 		/* insert the new entry: mark the entry NEW */
995 		xad = &sp->xad[skip];
996 		XT_PUTENTRY(xad, split->flag, split->off, split->len,
997 			    split->addr);
998 
999 		/* advance next available entry index */
1000 		sp->header.nextindex =
1001 		    cpu_to_le16(le16_to_cpu(sp->header.nextindex) + 1);
1002 
1003 		/* Don't log it if there are no links to the file */
1004 		if (!test_cflag(COMMIT_Nolink, ip)) {
1005 			tlck = txLock(tid, ip, smp, tlckXTREE | tlckGROW);
1006 			xtlck = (struct xtlock *) & tlck->lock;
1007 			xtlck->lwm.offset = (xtlck->lwm.offset) ?
1008 			    min(skip, (int)xtlck->lwm.offset) : skip;
1009 			xtlck->lwm.length =
1010 			    le16_to_cpu(sp->header.nextindex) -
1011 			    xtlck->lwm.offset;
1012 		}
1013 
1014 		return 0;
1015 	}
1016 
1017 	/*
1018 	 * allocate new index blocks to cover index page split(s)
1019 	 *
1020 	 * allocation hint: ?
1021 	 */
1022 	if (split->pxdlist == NULL) {
1023 		nsplit = btstack->nsplit;
1024 		split->pxdlist = &pxdlist;
1025 		pxdlist.maxnpxd = pxdlist.npxd = 0;
1026 		pxd = &pxdlist.pxd[0];
1027 		xlen = JFS_SBI(ip->i_sb)->nbperpage;
1028 		for (; nsplit > 0; nsplit--, pxd++) {
1029 			if ((rc = dbAlloc(ip, (s64) 0, (s64) xlen, &xaddr))
1030 			    == 0) {
1031 				PXDaddress(pxd, xaddr);
1032 				PXDlength(pxd, xlen);
1033 
1034 				pxdlist.maxnpxd++;
1035 
1036 				continue;
1037 			}
1038 
1039 			/* undo allocation */
1040 
1041 			XT_PUTPAGE(smp);
1042 			return rc;
1043 		}
1044 	}
1045 
1046 	/*
1047 	 * Split leaf page <sp> into <sp> and a new right page <rp>.
1048 	 *
1049 	 * The split routines insert the new entry into the leaf page,
1050 	 * and acquire txLock as appropriate.
1051 	 * return <rp> pinned and its block number <rpbn>.
1052 	 */
1053 	rc = (sp->header.flag & BT_ROOT) ?
1054 	    xtSplitRoot(tid, ip, split, &rmp) :
1055 	    xtSplitPage(tid, ip, split, &rmp, &rbn);
1056 
1057 	XT_PUTPAGE(smp);
1058 
1059 	if (rc)
1060 		return -EIO;
1061 	/*
1062 	 * propagate up the router entry for the leaf page just split
1063 	 *
1064 	 * insert a router entry for the new page into the parent page,
1065 	 * propagate the insert/split up the tree by walking back the stack
1066 	 * of (bn of parent page, index of child page entry in parent page)
1067 	 * that were traversed during the search for the page that split.
1068 	 *
1069 	 * the propagation of insert/split up the tree stops if the root
1070 	 * splits or the page inserted into doesn't have to split to hold
1071 	 * the new entry.
1072 	 *
1073 	 * the parent entry for the split page remains the same, and
1074 	 * a new entry is inserted at its right with the first key and
1075 	 * block number of the new right page.
1076 	 *
1077 	 * There are a maximum of 3 pages pinned at any time:
1078 	 * right child, left parent and right parent (when the parent splits)
1079 	 * to keep the child page pinned while working on the parent.
1080 	 * make sure that all pins are released at exit.
1081 	 */
1082 	while ((parent = BT_POP(btstack)) != NULL) {
1083 		/* parent page specified by stack frame <parent> */
1084 
1085 		/* keep current child pages <rcp> pinned */
1086 		rcmp = rmp;
1087 		rcbn = rbn;
1088 		rcp = XT_PAGE(ip, rcmp);
1089 
1090 		/*
1091 		 * insert router entry in parent for new right child page <rp>
1092 		 */
1093 		/* get/pin the parent page <sp> */
1094 		XT_GETPAGE(ip, parent->bn, smp, PSIZE, sp, rc);
1095 		if (rc) {
1096 			XT_PUTPAGE(rcmp);
1097 			return rc;
1098 		}
1099 
1100 		/*
1101 		 * The new key entry goes ONE AFTER the index of parent entry,
1102 		 * because the split was to the right.
1103 		 */
1104 		skip = parent->index + 1;
1105 
1106 		/*
1107 		 * split or shift right remaining entries of the parent page
1108 		 */
1109 		nextindex = le16_to_cpu(sp->header.nextindex);
1110 		/*
1111 		 * parent page is full - split the parent page
1112 		 */
1113 		if (nextindex == le16_to_cpu(sp->header.maxentry)) {
1114 			/* init for parent page split */
1115 			split->mp = smp;
1116 			split->index = skip;	/* index at insert */
1117 			split->flag = XAD_NEW;
1118 			split->off = offsetXAD(&rcp->xad[XTENTRYSTART]);
1119 			split->len = JFS_SBI(ip->i_sb)->nbperpage;
1120 			split->addr = rcbn;
1121 
1122 			/* unpin previous right child page */
1123 			XT_PUTPAGE(rcmp);
1124 
1125 			/* The split routines insert the new entry,
1126 			 * and acquire txLock as appropriate.
1127 			 * return <rp> pinned and its block number <rpbn>.
1128 			 */
1129 			rc = (sp->header.flag & BT_ROOT) ?
1130 			    xtSplitRoot(tid, ip, split, &rmp) :
1131 			    xtSplitPage(tid, ip, split, &rmp, &rbn);
1132 			if (rc) {
1133 				XT_PUTPAGE(smp);
1134 				return rc;
1135 			}
1136 
1137 			XT_PUTPAGE(smp);
1138 			/* keep new child page <rp> pinned */
1139 		}
1140 		/*
1141 		 * parent page is not full - insert in parent page
1142 		 */
1143 		else {
1144 			/*
1145 			 * insert router entry in parent for the right child
1146 			 * page from the first entry of the right child page:
1147 			 */
1148 			/*
1149 			 * acquire a transaction lock on the parent page;
1150 			 *
1151 			 * action: router xad insertion;
1152 			 */
1153 			BT_MARK_DIRTY(smp, ip);
1154 
1155 			/*
1156 			 * if insert into middle, shift right remaining entries
1157 			 */
1158 			if (skip < nextindex)
1159 				memmove(&sp->xad[skip + 1], &sp->xad[skip],
1160 					(nextindex -
1161 					 skip) << L2XTSLOTSIZE);
1162 
1163 			/* insert the router entry */
1164 			xad = &sp->xad[skip];
1165 			XT_PUTENTRY(xad, XAD_NEW,
1166 				    offsetXAD(&rcp->xad[XTENTRYSTART]),
1167 				    JFS_SBI(ip->i_sb)->nbperpage, rcbn);
1168 
1169 			/* advance next available entry index. */
1170 			sp->header.nextindex =
1171 			    cpu_to_le16(le16_to_cpu(sp->header.nextindex) +
1172 					1);
1173 
1174 			/* Don't log it if there are no links to the file */
1175 			if (!test_cflag(COMMIT_Nolink, ip)) {
1176 				tlck = txLock(tid, ip, smp,
1177 					      tlckXTREE | tlckGROW);
1178 				xtlck = (struct xtlock *) & tlck->lock;
1179 				xtlck->lwm.offset = (xtlck->lwm.offset) ?
1180 				    min(skip, (int)xtlck->lwm.offset) : skip;
1181 				xtlck->lwm.length =
1182 				    le16_to_cpu(sp->header.nextindex) -
1183 				    xtlck->lwm.offset;
1184 			}
1185 
1186 			/* unpin parent page */
1187 			XT_PUTPAGE(smp);
1188 
1189 			/* exit propagate up */
1190 			break;
1191 		}
1192 	}
1193 
1194 	/* unpin current right page */
1195 	XT_PUTPAGE(rmp);
1196 
1197 	return 0;
1198 }
1199 
1200 
1201 /*
1202  *	xtSplitPage()
1203  *
1204  * function:
1205  *	split a full non-root page into
1206  *	original/split/left page and new right page
1207  *	i.e., the original/split page remains as left page.
1208  *
1209  * parameter:
1210  *	int		tid,
1211  *	struct inode	*ip,
1212  *	struct xtsplit	*split,
1213  *	struct metapage	**rmpp,
1214  *	u64		*rbnp,
1215  *
1216  * return:
1217  *	Pointer to page in which to insert or NULL on error.
1218  */
1219 static int
1220 xtSplitPage(tid_t tid, struct inode *ip,
1221 	    struct xtsplit * split, struct metapage ** rmpp, s64 * rbnp)
1222 {
1223 	int rc = 0;
1224 	struct metapage *smp;
1225 	xtpage_t *sp;
1226 	struct metapage *rmp;
1227 	xtpage_t *rp;		/* new right page allocated */
1228 	s64 rbn;		/* new right page block number */
1229 	struct metapage *mp;
1230 	xtpage_t *p;
1231 	s64 nextbn;
1232 	int skip, maxentry, middle, righthalf, n;
1233 	xad_t *xad;
1234 	struct pxdlist *pxdlist;
1235 	pxd_t *pxd;
1236 	struct tlock *tlck;
1237 	struct xtlock *sxtlck = NULL, *rxtlck = NULL;
1238 	int quota_allocation = 0;
1239 
1240 	smp = split->mp;
1241 	sp = XT_PAGE(ip, smp);
1242 
1243 	INCREMENT(xtStat.split);
1244 
1245 	pxdlist = split->pxdlist;
1246 	pxd = &pxdlist->pxd[pxdlist->npxd];
1247 	pxdlist->npxd++;
1248 	rbn = addressPXD(pxd);
1249 
1250 	/* Allocate blocks to quota. */
1251 	if (DQUOT_ALLOC_BLOCK(ip, lengthPXD(pxd))) {
1252 		rc = -EDQUOT;
1253 		goto clean_up;
1254 	}
1255 
1256 	quota_allocation += lengthPXD(pxd);
1257 
1258 	/*
1259 	 * allocate the new right page for the split
1260 	 */
1261 	rmp = get_metapage(ip, rbn, PSIZE, 1);
1262 	if (rmp == NULL) {
1263 		rc = -EIO;
1264 		goto clean_up;
1265 	}
1266 
1267 	jfs_info("xtSplitPage: ip:0x%p smp:0x%p rmp:0x%p", ip, smp, rmp);
1268 
1269 	BT_MARK_DIRTY(rmp, ip);
1270 	/*
1271 	 * action: new page;
1272 	 */
1273 
1274 	rp = (xtpage_t *) rmp->data;
1275 	rp->header.self = *pxd;
1276 	rp->header.flag = sp->header.flag & BT_TYPE;
1277 	rp->header.maxentry = sp->header.maxentry;	/* little-endian */
1278 	rp->header.nextindex = cpu_to_le16(XTENTRYSTART);
1279 
1280 	BT_MARK_DIRTY(smp, ip);
1281 	/* Don't log it if there are no links to the file */
1282 	if (!test_cflag(COMMIT_Nolink, ip)) {
1283 		/*
1284 		 * acquire a transaction lock on the new right page;
1285 		 */
1286 		tlck = txLock(tid, ip, rmp, tlckXTREE | tlckNEW);
1287 		rxtlck = (struct xtlock *) & tlck->lock;
1288 		rxtlck->lwm.offset = XTENTRYSTART;
1289 		/*
1290 		 * acquire a transaction lock on the split page
1291 		 */
1292 		tlck = txLock(tid, ip, smp, tlckXTREE | tlckGROW);
1293 		sxtlck = (struct xtlock *) & tlck->lock;
1294 	}
1295 
1296 	/*
1297 	 * initialize/update sibling pointers of <sp> and <rp>
1298 	 */
1299 	nextbn = le64_to_cpu(sp->header.next);
1300 	rp->header.next = cpu_to_le64(nextbn);
1301 	rp->header.prev = cpu_to_le64(addressPXD(&sp->header.self));
1302 	sp->header.next = cpu_to_le64(rbn);
1303 
1304 	skip = split->index;
1305 
1306 	/*
1307 	 *	sequential append at tail (after last entry of last page)
1308 	 *
1309 	 * if splitting the last page on a level because of appending
1310 	 * a entry to it (skip is maxentry), it's likely that the access is
1311 	 * sequential. adding an empty page on the side of the level is less
1312 	 * work and can push the fill factor much higher than normal.
1313 	 * if we're wrong it's no big deal -  we will do the split the right
1314 	 * way next time.
1315 	 * (it may look like it's equally easy to do a similar hack for
1316 	 * reverse sorted data, that is, split the tree left, but it's not.
1317 	 * Be my guest.)
1318 	 */
1319 	if (nextbn == 0 && skip == le16_to_cpu(sp->header.maxentry)) {
1320 		/*
1321 		 * acquire a transaction lock on the new/right page;
1322 		 *
1323 		 * action: xad insertion;
1324 		 */
1325 		/* insert entry at the first entry of the new right page */
1326 		xad = &rp->xad[XTENTRYSTART];
1327 		XT_PUTENTRY(xad, split->flag, split->off, split->len,
1328 			    split->addr);
1329 
1330 		rp->header.nextindex = cpu_to_le16(XTENTRYSTART + 1);
1331 
1332 		if (!test_cflag(COMMIT_Nolink, ip)) {
1333 			/* rxtlck->lwm.offset = XTENTRYSTART; */
1334 			rxtlck->lwm.length = 1;
1335 		}
1336 
1337 		*rmpp = rmp;
1338 		*rbnp = rbn;
1339 
1340 		jfs_info("xtSplitPage: sp:0x%p rp:0x%p", sp, rp);
1341 		return 0;
1342 	}
1343 
1344 	/*
1345 	 *	non-sequential insert (at possibly middle page)
1346 	 */
1347 
1348 	/*
1349 	 * update previous pointer of old next/right page of <sp>
1350 	 */
1351 	if (nextbn != 0) {
1352 		XT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
1353 		if (rc) {
1354 			XT_PUTPAGE(rmp);
1355 			goto clean_up;
1356 		}
1357 
1358 		BT_MARK_DIRTY(mp, ip);
1359 		/*
1360 		 * acquire a transaction lock on the next page;
1361 		 *
1362 		 * action:sibling pointer update;
1363 		 */
1364 		if (!test_cflag(COMMIT_Nolink, ip))
1365 			tlck = txLock(tid, ip, mp, tlckXTREE | tlckRELINK);
1366 
1367 		p->header.prev = cpu_to_le64(rbn);
1368 
1369 		/* sibling page may have been updated previously, or
1370 		 * it may be updated later;
1371 		 */
1372 
1373 		XT_PUTPAGE(mp);
1374 	}
1375 
1376 	/*
1377 	 * split the data between the split and new/right pages
1378 	 */
1379 	maxentry = le16_to_cpu(sp->header.maxentry);
1380 	middle = maxentry >> 1;
1381 	righthalf = maxentry - middle;
1382 
1383 	/*
1384 	 * skip index in old split/left page - insert into left page:
1385 	 */
1386 	if (skip <= middle) {
1387 		/* move right half of split page to the new right page */
1388 		memmove(&rp->xad[XTENTRYSTART], &sp->xad[middle],
1389 			righthalf << L2XTSLOTSIZE);
1390 
1391 		/* shift right tail of left half to make room for new entry */
1392 		if (skip < middle)
1393 			memmove(&sp->xad[skip + 1], &sp->xad[skip],
1394 				(middle - skip) << L2XTSLOTSIZE);
1395 
1396 		/* insert new entry */
1397 		xad = &sp->xad[skip];
1398 		XT_PUTENTRY(xad, split->flag, split->off, split->len,
1399 			    split->addr);
1400 
1401 		/* update page header */
1402 		sp->header.nextindex = cpu_to_le16(middle + 1);
1403 		if (!test_cflag(COMMIT_Nolink, ip)) {
1404 			sxtlck->lwm.offset = (sxtlck->lwm.offset) ?
1405 			    min(skip, (int)sxtlck->lwm.offset) : skip;
1406 		}
1407 
1408 		rp->header.nextindex =
1409 		    cpu_to_le16(XTENTRYSTART + righthalf);
1410 	}
1411 	/*
1412 	 * skip index in new right page - insert into right page:
1413 	 */
1414 	else {
1415 		/* move left head of right half to right page */
1416 		n = skip - middle;
1417 		memmove(&rp->xad[XTENTRYSTART], &sp->xad[middle],
1418 			n << L2XTSLOTSIZE);
1419 
1420 		/* insert new entry */
1421 		n += XTENTRYSTART;
1422 		xad = &rp->xad[n];
1423 		XT_PUTENTRY(xad, split->flag, split->off, split->len,
1424 			    split->addr);
1425 
1426 		/* move right tail of right half to right page */
1427 		if (skip < maxentry)
1428 			memmove(&rp->xad[n + 1], &sp->xad[skip],
1429 				(maxentry - skip) << L2XTSLOTSIZE);
1430 
1431 		/* update page header */
1432 		sp->header.nextindex = cpu_to_le16(middle);
1433 		if (!test_cflag(COMMIT_Nolink, ip)) {
1434 			sxtlck->lwm.offset = (sxtlck->lwm.offset) ?
1435 			    min(middle, (int)sxtlck->lwm.offset) : middle;
1436 		}
1437 
1438 		rp->header.nextindex = cpu_to_le16(XTENTRYSTART +
1439 						   righthalf + 1);
1440 	}
1441 
1442 	if (!test_cflag(COMMIT_Nolink, ip)) {
1443 		sxtlck->lwm.length = le16_to_cpu(sp->header.nextindex) -
1444 		    sxtlck->lwm.offset;
1445 
1446 		/* rxtlck->lwm.offset = XTENTRYSTART; */
1447 		rxtlck->lwm.length = le16_to_cpu(rp->header.nextindex) -
1448 		    XTENTRYSTART;
1449 	}
1450 
1451 	*rmpp = rmp;
1452 	*rbnp = rbn;
1453 
1454 	jfs_info("xtSplitPage: sp:0x%p rp:0x%p", sp, rp);
1455 	return rc;
1456 
1457       clean_up:
1458 
1459 	/* Rollback quota allocation. */
1460 	if (quota_allocation)
1461 		DQUOT_FREE_BLOCK(ip, quota_allocation);
1462 
1463 	return (rc);
1464 }
1465 
1466 
1467 /*
1468  *	xtSplitRoot()
1469  *
1470  * function:
1471  *	split the full root page into original/root/split page and new
1472  *	right page
1473  *	i.e., root remains fixed in tree anchor (inode) and the root is
1474  *	copied to a single new right child page since root page <<
1475  *	non-root page, and the split root page contains a single entry
1476  *	for the new right child page.
1477  *
1478  * parameter:
1479  *	int		tid,
1480  *	struct inode	*ip,
1481  *	struct xtsplit	*split,
1482  *	struct metapage	**rmpp)
1483  *
1484  * return:
1485  *	Pointer to page in which to insert or NULL on error.
1486  */
1487 static int
1488 xtSplitRoot(tid_t tid,
1489 	    struct inode *ip, struct xtsplit * split, struct metapage ** rmpp)
1490 {
1491 	xtpage_t *sp;
1492 	struct metapage *rmp;
1493 	xtpage_t *rp;
1494 	s64 rbn;
1495 	int skip, nextindex;
1496 	xad_t *xad;
1497 	pxd_t *pxd;
1498 	struct pxdlist *pxdlist;
1499 	struct tlock *tlck;
1500 	struct xtlock *xtlck;
1501 
1502 	sp = &JFS_IP(ip)->i_xtroot;
1503 
1504 	INCREMENT(xtStat.split);
1505 
1506 	/*
1507 	 *	allocate a single (right) child page
1508 	 */
1509 	pxdlist = split->pxdlist;
1510 	pxd = &pxdlist->pxd[pxdlist->npxd];
1511 	pxdlist->npxd++;
1512 	rbn = addressPXD(pxd);
1513 	rmp = get_metapage(ip, rbn, PSIZE, 1);
1514 	if (rmp == NULL)
1515 		return -EIO;
1516 
1517 	/* Allocate blocks to quota. */
1518 	if (DQUOT_ALLOC_BLOCK(ip, lengthPXD(pxd))) {
1519 		release_metapage(rmp);
1520 		return -EDQUOT;
1521 	}
1522 
1523 	jfs_info("xtSplitRoot: ip:0x%p rmp:0x%p", ip, rmp);
1524 
1525 	/*
1526 	 * acquire a transaction lock on the new right page;
1527 	 *
1528 	 * action: new page;
1529 	 */
1530 	BT_MARK_DIRTY(rmp, ip);
1531 
1532 	rp = (xtpage_t *) rmp->data;
1533 	rp->header.flag =
1534 	    (sp->header.flag & BT_LEAF) ? BT_LEAF : BT_INTERNAL;
1535 	rp->header.self = *pxd;
1536 	rp->header.nextindex = cpu_to_le16(XTENTRYSTART);
1537 	rp->header.maxentry = cpu_to_le16(PSIZE >> L2XTSLOTSIZE);
1538 
1539 	/* initialize sibling pointers */
1540 	rp->header.next = 0;
1541 	rp->header.prev = 0;
1542 
1543 	/*
1544 	 * copy the in-line root page into new right page extent
1545 	 */
1546 	nextindex = le16_to_cpu(sp->header.maxentry);
1547 	memmove(&rp->xad[XTENTRYSTART], &sp->xad[XTENTRYSTART],
1548 		(nextindex - XTENTRYSTART) << L2XTSLOTSIZE);
1549 
1550 	/*
1551 	 * insert the new entry into the new right/child page
1552 	 * (skip index in the new right page will not change)
1553 	 */
1554 	skip = split->index;
1555 	/* if insert into middle, shift right remaining entries */
1556 	if (skip != nextindex)
1557 		memmove(&rp->xad[skip + 1], &rp->xad[skip],
1558 			(nextindex - skip) * sizeof(xad_t));
1559 
1560 	xad = &rp->xad[skip];
1561 	XT_PUTENTRY(xad, split->flag, split->off, split->len, split->addr);
1562 
1563 	/* update page header */
1564 	rp->header.nextindex = cpu_to_le16(nextindex + 1);
1565 
1566 	if (!test_cflag(COMMIT_Nolink, ip)) {
1567 		tlck = txLock(tid, ip, rmp, tlckXTREE | tlckNEW);
1568 		xtlck = (struct xtlock *) & tlck->lock;
1569 		xtlck->lwm.offset = XTENTRYSTART;
1570 		xtlck->lwm.length = le16_to_cpu(rp->header.nextindex) -
1571 		    XTENTRYSTART;
1572 	}
1573 
1574 	/*
1575 	 *	reset the root
1576 	 *
1577 	 * init root with the single entry for the new right page
1578 	 * set the 1st entry offset to 0, which force the left-most key
1579 	 * at any level of the tree to be less than any search key.
1580 	 */
1581 	/*
1582 	 * acquire a transaction lock on the root page (in-memory inode);
1583 	 *
1584 	 * action: root split;
1585 	 */
1586 	BT_MARK_DIRTY(split->mp, ip);
1587 
1588 	xad = &sp->xad[XTENTRYSTART];
1589 	XT_PUTENTRY(xad, XAD_NEW, 0, JFS_SBI(ip->i_sb)->nbperpage, rbn);
1590 
1591 	/* update page header of root */
1592 	sp->header.flag &= ~BT_LEAF;
1593 	sp->header.flag |= BT_INTERNAL;
1594 
1595 	sp->header.nextindex = cpu_to_le16(XTENTRYSTART + 1);
1596 
1597 	if (!test_cflag(COMMIT_Nolink, ip)) {
1598 		tlck = txLock(tid, ip, split->mp, tlckXTREE | tlckGROW);
1599 		xtlck = (struct xtlock *) & tlck->lock;
1600 		xtlck->lwm.offset = XTENTRYSTART;
1601 		xtlck->lwm.length = 1;
1602 	}
1603 
1604 	*rmpp = rmp;
1605 
1606 	jfs_info("xtSplitRoot: sp:0x%p rp:0x%p", sp, rp);
1607 	return 0;
1608 }
1609 
1610 
1611 /*
1612  *	xtExtend()
1613  *
1614  * function: extend in-place;
1615  *
1616  * note: existing extent may or may not have been committed.
1617  * caller is responsible for pager buffer cache update, and
1618  * working block allocation map update;
1619  * update pmap: alloc whole extended extent;
1620  */
1621 int xtExtend(tid_t tid,		/* transaction id */
1622 	     struct inode *ip, s64 xoff,	/* delta extent offset */
1623 	     s32 xlen,		/* delta extent length */
1624 	     int flag)
1625 {
1626 	int rc = 0;
1627 	int cmp;
1628 	struct metapage *mp;	/* meta-page buffer */
1629 	xtpage_t *p;		/* base B+-tree index page */
1630 	s64 bn;
1631 	int index, nextindex, len;
1632 	struct btstack btstack;	/* traverse stack */
1633 	struct xtsplit split;	/* split information */
1634 	xad_t *xad;
1635 	s64 xaddr;
1636 	struct tlock *tlck;
1637 	struct xtlock *xtlck = NULL;
1638 
1639 	jfs_info("xtExtend: nxoff:0x%lx nxlen:0x%x", (ulong) xoff, xlen);
1640 
1641 	/* there must exist extent to be extended */
1642 	if ((rc = xtSearch(ip, xoff - 1, NULL, &cmp, &btstack, XT_INSERT)))
1643 		return rc;
1644 
1645 	/* retrieve search result */
1646 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
1647 
1648 	if (cmp != 0) {
1649 		XT_PUTPAGE(mp);
1650 		jfs_error(ip->i_sb, "xtExtend: xtSearch did not find extent");
1651 		return -EIO;
1652 	}
1653 
1654 	/* extension must be contiguous */
1655 	xad = &p->xad[index];
1656 	if ((offsetXAD(xad) + lengthXAD(xad)) != xoff) {
1657 		XT_PUTPAGE(mp);
1658 		jfs_error(ip->i_sb, "xtExtend: extension is not contiguous");
1659 		return -EIO;
1660 	}
1661 
1662 	/*
1663 	 * acquire a transaction lock on the leaf page;
1664 	 *
1665 	 * action: xad insertion/extension;
1666 	 */
1667 	BT_MARK_DIRTY(mp, ip);
1668 	if (!test_cflag(COMMIT_Nolink, ip)) {
1669 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
1670 		xtlck = (struct xtlock *) & tlck->lock;
1671 	}
1672 
1673 	/* extend will overflow extent ? */
1674 	xlen = lengthXAD(xad) + xlen;
1675 	if ((len = xlen - MAXXLEN) <= 0)
1676 		goto extendOld;
1677 
1678 	/*
1679 	 *	extent overflow: insert entry for new extent
1680 	 */
1681 //insertNew:
1682 	xoff = offsetXAD(xad) + MAXXLEN;
1683 	xaddr = addressXAD(xad) + MAXXLEN;
1684 	nextindex = le16_to_cpu(p->header.nextindex);
1685 
1686 	/*
1687 	 *	if the leaf page is full, insert the new entry and
1688 	 *	propagate up the router entry for the new page from split
1689 	 *
1690 	 * The xtSplitUp() will insert the entry and unpin the leaf page.
1691 	 */
1692 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
1693 		/* xtSpliUp() unpins leaf pages */
1694 		split.mp = mp;
1695 		split.index = index + 1;
1696 		split.flag = XAD_NEW;
1697 		split.off = xoff;	/* split offset */
1698 		split.len = len;
1699 		split.addr = xaddr;
1700 		split.pxdlist = NULL;
1701 		if ((rc = xtSplitUp(tid, ip, &split, &btstack)))
1702 			return rc;
1703 
1704 		/* get back old page */
1705 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
1706 		if (rc)
1707 			return rc;
1708 		/*
1709 		 * if leaf root has been split, original root has been
1710 		 * copied to new child page, i.e., original entry now
1711 		 * resides on the new child page;
1712 		 */
1713 		if (p->header.flag & BT_INTERNAL) {
1714 			ASSERT(p->header.nextindex ==
1715 			       cpu_to_le16(XTENTRYSTART + 1));
1716 			xad = &p->xad[XTENTRYSTART];
1717 			bn = addressXAD(xad);
1718 			XT_PUTPAGE(mp);
1719 
1720 			/* get new child page */
1721 			XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
1722 			if (rc)
1723 				return rc;
1724 
1725 			BT_MARK_DIRTY(mp, ip);
1726 			if (!test_cflag(COMMIT_Nolink, ip)) {
1727 				tlck = txLock(tid, ip, mp, tlckXTREE|tlckGROW);
1728 				xtlck = (struct xtlock *) & tlck->lock;
1729 			}
1730 		}
1731 	}
1732 	/*
1733 	 *	insert the new entry into the leaf page
1734 	 */
1735 	else {
1736 		/* insert the new entry: mark the entry NEW */
1737 		xad = &p->xad[index + 1];
1738 		XT_PUTENTRY(xad, XAD_NEW, xoff, len, xaddr);
1739 
1740 		/* advance next available entry index */
1741 		p->header.nextindex =
1742 		    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
1743 	}
1744 
1745 	/* get back old entry */
1746 	xad = &p->xad[index];
1747 	xlen = MAXXLEN;
1748 
1749 	/*
1750 	 * extend old extent
1751 	 */
1752       extendOld:
1753 	XADlength(xad, xlen);
1754 	if (!(xad->flag & XAD_NEW))
1755 		xad->flag |= XAD_EXTENDED;
1756 
1757 	if (!test_cflag(COMMIT_Nolink, ip)) {
1758 		xtlck->lwm.offset =
1759 		    (xtlck->lwm.offset) ? min(index,
1760 					      (int)xtlck->lwm.offset) : index;
1761 		xtlck->lwm.length =
1762 		    le16_to_cpu(p->header.nextindex) - xtlck->lwm.offset;
1763 	}
1764 
1765 	/* unpin the leaf page */
1766 	XT_PUTPAGE(mp);
1767 
1768 	return rc;
1769 }
1770 
1771 #ifdef _NOTYET
1772 /*
1773  *	xtTailgate()
1774  *
1775  * function: split existing 'tail' extent
1776  *	(split offset >= start offset of tail extent), and
1777  *	relocate and extend the split tail half;
1778  *
1779  * note: existing extent may or may not have been committed.
1780  * caller is responsible for pager buffer cache update, and
1781  * working block allocation map update;
1782  * update pmap: free old split tail extent, alloc new extent;
1783  */
1784 int xtTailgate(tid_t tid,		/* transaction id */
1785 	       struct inode *ip, s64 xoff,	/* split/new extent offset */
1786 	       s32 xlen,	/* new extent length */
1787 	       s64 xaddr,	/* new extent address */
1788 	       int flag)
1789 {
1790 	int rc = 0;
1791 	int cmp;
1792 	struct metapage *mp;	/* meta-page buffer */
1793 	xtpage_t *p;		/* base B+-tree index page */
1794 	s64 bn;
1795 	int index, nextindex, llen, rlen;
1796 	struct btstack btstack;	/* traverse stack */
1797 	struct xtsplit split;	/* split information */
1798 	xad_t *xad;
1799 	struct tlock *tlck;
1800 	struct xtlock *xtlck = 0;
1801 	struct tlock *mtlck;
1802 	struct maplock *pxdlock;
1803 
1804 /*
1805 printf("xtTailgate: nxoff:0x%lx nxlen:0x%x nxaddr:0x%lx\n",
1806 	(ulong)xoff, xlen, (ulong)xaddr);
1807 */
1808 
1809 	/* there must exist extent to be tailgated */
1810 	if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, XT_INSERT)))
1811 		return rc;
1812 
1813 	/* retrieve search result */
1814 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
1815 
1816 	if (cmp != 0) {
1817 		XT_PUTPAGE(mp);
1818 		jfs_error(ip->i_sb, "xtTailgate: couldn't find extent");
1819 		return -EIO;
1820 	}
1821 
1822 	/* entry found must be last entry */
1823 	nextindex = le16_to_cpu(p->header.nextindex);
1824 	if (index != nextindex - 1) {
1825 		XT_PUTPAGE(mp);
1826 		jfs_error(ip->i_sb,
1827 			  "xtTailgate: the entry found is not the last entry");
1828 		return -EIO;
1829 	}
1830 
1831 	BT_MARK_DIRTY(mp, ip);
1832 	/*
1833 	 * acquire tlock of the leaf page containing original entry
1834 	 */
1835 	if (!test_cflag(COMMIT_Nolink, ip)) {
1836 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
1837 		xtlck = (struct xtlock *) & tlck->lock;
1838 	}
1839 
1840 	/* completely replace extent ? */
1841 	xad = &p->xad[index];
1842 /*
1843 printf("xtTailgate: xoff:0x%lx xlen:0x%x xaddr:0x%lx\n",
1844 	(ulong)offsetXAD(xad), lengthXAD(xad), (ulong)addressXAD(xad));
1845 */
1846 	if ((llen = xoff - offsetXAD(xad)) == 0)
1847 		goto updateOld;
1848 
1849 	/*
1850 	 *	partially replace extent: insert entry for new extent
1851 	 */
1852 //insertNew:
1853 	/*
1854 	 *	if the leaf page is full, insert the new entry and
1855 	 *	propagate up the router entry for the new page from split
1856 	 *
1857 	 * The xtSplitUp() will insert the entry and unpin the leaf page.
1858 	 */
1859 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
1860 		/* xtSpliUp() unpins leaf pages */
1861 		split.mp = mp;
1862 		split.index = index + 1;
1863 		split.flag = XAD_NEW;
1864 		split.off = xoff;	/* split offset */
1865 		split.len = xlen;
1866 		split.addr = xaddr;
1867 		split.pxdlist = NULL;
1868 		if ((rc = xtSplitUp(tid, ip, &split, &btstack)))
1869 			return rc;
1870 
1871 		/* get back old page */
1872 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
1873 		if (rc)
1874 			return rc;
1875 		/*
1876 		 * if leaf root has been split, original root has been
1877 		 * copied to new child page, i.e., original entry now
1878 		 * resides on the new child page;
1879 		 */
1880 		if (p->header.flag & BT_INTERNAL) {
1881 			ASSERT(p->header.nextindex ==
1882 			       cpu_to_le16(XTENTRYSTART + 1));
1883 			xad = &p->xad[XTENTRYSTART];
1884 			bn = addressXAD(xad);
1885 			XT_PUTPAGE(mp);
1886 
1887 			/* get new child page */
1888 			XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
1889 			if (rc)
1890 				return rc;
1891 
1892 			BT_MARK_DIRTY(mp, ip);
1893 			if (!test_cflag(COMMIT_Nolink, ip)) {
1894 				tlck = txLock(tid, ip, mp, tlckXTREE|tlckGROW);
1895 				xtlck = (struct xtlock *) & tlck->lock;
1896 			}
1897 		}
1898 	}
1899 	/*
1900 	 *	insert the new entry into the leaf page
1901 	 */
1902 	else {
1903 		/* insert the new entry: mark the entry NEW */
1904 		xad = &p->xad[index + 1];
1905 		XT_PUTENTRY(xad, XAD_NEW, xoff, xlen, xaddr);
1906 
1907 		/* advance next available entry index */
1908 		p->header.nextindex =
1909 		    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
1910 	}
1911 
1912 	/* get back old XAD */
1913 	xad = &p->xad[index];
1914 
1915 	/*
1916 	 * truncate/relocate old extent at split offset
1917 	 */
1918       updateOld:
1919 	/* update dmap for old/committed/truncated extent */
1920 	rlen = lengthXAD(xad) - llen;
1921 	if (!(xad->flag & XAD_NEW)) {
1922 		/* free from PWMAP at commit */
1923 		if (!test_cflag(COMMIT_Nolink, ip)) {
1924 			mtlck = txMaplock(tid, ip, tlckMAP);
1925 			pxdlock = (struct maplock *) & mtlck->lock;
1926 			pxdlock->flag = mlckFREEPXD;
1927 			PXDaddress(&pxdlock->pxd, addressXAD(xad) + llen);
1928 			PXDlength(&pxdlock->pxd, rlen);
1929 			pxdlock->index = 1;
1930 		}
1931 	} else
1932 		/* free from WMAP */
1933 		dbFree(ip, addressXAD(xad) + llen, (s64) rlen);
1934 
1935 	if (llen)
1936 		/* truncate */
1937 		XADlength(xad, llen);
1938 	else
1939 		/* replace */
1940 		XT_PUTENTRY(xad, XAD_NEW, xoff, xlen, xaddr);
1941 
1942 	if (!test_cflag(COMMIT_Nolink, ip)) {
1943 		xtlck->lwm.offset = (xtlck->lwm.offset) ?
1944 		    min(index, (int)xtlck->lwm.offset) : index;
1945 		xtlck->lwm.length = le16_to_cpu(p->header.nextindex) -
1946 		    xtlck->lwm.offset;
1947 	}
1948 
1949 	/* unpin the leaf page */
1950 	XT_PUTPAGE(mp);
1951 
1952 	return rc;
1953 }
1954 #endif /* _NOTYET */
1955 
1956 /*
1957  *	xtUpdate()
1958  *
1959  * function: update XAD;
1960  *
1961  *	update extent for allocated_but_not_recorded or
1962  *	compressed extent;
1963  *
1964  * parameter:
1965  *	nxad	- new XAD;
1966  *		logical extent of the specified XAD must be completely
1967  *		contained by an existing XAD;
1968  */
1969 int xtUpdate(tid_t tid, struct inode *ip, xad_t * nxad)
1970 {				/* new XAD */
1971 	int rc = 0;
1972 	int cmp;
1973 	struct metapage *mp;	/* meta-page buffer */
1974 	xtpage_t *p;		/* base B+-tree index page */
1975 	s64 bn;
1976 	int index0, index, newindex, nextindex;
1977 	struct btstack btstack;	/* traverse stack */
1978 	struct xtsplit split;	/* split information */
1979 	xad_t *xad, *lxad, *rxad;
1980 	int xflag;
1981 	s64 nxoff, xoff;
1982 	int nxlen, xlen, lxlen, rxlen;
1983 	s64 nxaddr, xaddr;
1984 	struct tlock *tlck;
1985 	struct xtlock *xtlck = NULL;
1986 	int newpage = 0;
1987 
1988 	/* there must exist extent to be tailgated */
1989 	nxoff = offsetXAD(nxad);
1990 	nxlen = lengthXAD(nxad);
1991 	nxaddr = addressXAD(nxad);
1992 
1993 	if ((rc = xtSearch(ip, nxoff, NULL, &cmp, &btstack, XT_INSERT)))
1994 		return rc;
1995 
1996 	/* retrieve search result */
1997 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index0);
1998 
1999 	if (cmp != 0) {
2000 		XT_PUTPAGE(mp);
2001 		jfs_error(ip->i_sb, "xtUpdate: Could not find extent");
2002 		return -EIO;
2003 	}
2004 
2005 	BT_MARK_DIRTY(mp, ip);
2006 	/*
2007 	 * acquire tlock of the leaf page containing original entry
2008 	 */
2009 	if (!test_cflag(COMMIT_Nolink, ip)) {
2010 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
2011 		xtlck = (struct xtlock *) & tlck->lock;
2012 	}
2013 
2014 	xad = &p->xad[index0];
2015 	xflag = xad->flag;
2016 	xoff = offsetXAD(xad);
2017 	xlen = lengthXAD(xad);
2018 	xaddr = addressXAD(xad);
2019 
2020 	/* nXAD must be completely contained within XAD */
2021 	if ((xoff > nxoff) ||
2022 	    (nxoff + nxlen > xoff + xlen)) {
2023 		XT_PUTPAGE(mp);
2024 		jfs_error(ip->i_sb,
2025 			  "xtUpdate: nXAD in not completely contained within XAD");
2026 		return -EIO;
2027 	}
2028 
2029 	index = index0;
2030 	newindex = index + 1;
2031 	nextindex = le16_to_cpu(p->header.nextindex);
2032 
2033 #ifdef  _JFS_WIP_NOCOALESCE
2034 	if (xoff < nxoff)
2035 		goto updateRight;
2036 
2037 	/*
2038 	 * replace XAD with nXAD
2039 	 */
2040       replace:			/* (nxoff == xoff) */
2041 	if (nxlen == xlen) {
2042 		/* replace XAD with nXAD:recorded */
2043 		*xad = *nxad;
2044 		xad->flag = xflag & ~XAD_NOTRECORDED;
2045 
2046 		goto out;
2047 	} else			/* (nxlen < xlen) */
2048 		goto updateLeft;
2049 #endif				/* _JFS_WIP_NOCOALESCE */
2050 
2051 /* #ifdef _JFS_WIP_COALESCE */
2052 	if (xoff < nxoff)
2053 		goto coalesceRight;
2054 
2055 	/*
2056 	 * coalesce with left XAD
2057 	 */
2058 //coalesceLeft: /* (xoff == nxoff) */
2059 	/* is XAD first entry of page ? */
2060 	if (index == XTENTRYSTART)
2061 		goto replace;
2062 
2063 	/* is nXAD logically and physically contiguous with lXAD ? */
2064 	lxad = &p->xad[index - 1];
2065 	lxlen = lengthXAD(lxad);
2066 	if (!(lxad->flag & XAD_NOTRECORDED) &&
2067 	    (nxoff == offsetXAD(lxad) + lxlen) &&
2068 	    (nxaddr == addressXAD(lxad) + lxlen) &&
2069 	    (lxlen + nxlen < MAXXLEN)) {
2070 		/* extend right lXAD */
2071 		index0 = index - 1;
2072 		XADlength(lxad, lxlen + nxlen);
2073 
2074 		/* If we just merged two extents together, need to make sure the
2075 		 * right extent gets logged.  If the left one is marked XAD_NEW,
2076 		 * then we know it will be logged.  Otherwise, mark as
2077 		 * XAD_EXTENDED
2078 		 */
2079 		if (!(lxad->flag & XAD_NEW))
2080 			lxad->flag |= XAD_EXTENDED;
2081 
2082 		if (xlen > nxlen) {
2083 			/* truncate XAD */
2084 			XADoffset(xad, xoff + nxlen);
2085 			XADlength(xad, xlen - nxlen);
2086 			XADaddress(xad, xaddr + nxlen);
2087 			goto out;
2088 		} else {	/* (xlen == nxlen) */
2089 
2090 			/* remove XAD */
2091 			if (index < nextindex - 1)
2092 				memmove(&p->xad[index], &p->xad[index + 1],
2093 					(nextindex - index -
2094 					 1) << L2XTSLOTSIZE);
2095 
2096 			p->header.nextindex =
2097 			    cpu_to_le16(le16_to_cpu(p->header.nextindex) -
2098 					1);
2099 
2100 			index = index0;
2101 			newindex = index + 1;
2102 			nextindex = le16_to_cpu(p->header.nextindex);
2103 			xoff = nxoff = offsetXAD(lxad);
2104 			xlen = nxlen = lxlen + nxlen;
2105 			xaddr = nxaddr = addressXAD(lxad);
2106 			goto coalesceRight;
2107 		}
2108 	}
2109 
2110 	/*
2111 	 * replace XAD with nXAD
2112 	 */
2113       replace:			/* (nxoff == xoff) */
2114 	if (nxlen == xlen) {
2115 		/* replace XAD with nXAD:recorded */
2116 		*xad = *nxad;
2117 		xad->flag = xflag & ~XAD_NOTRECORDED;
2118 
2119 		goto coalesceRight;
2120 	} else			/* (nxlen < xlen) */
2121 		goto updateLeft;
2122 
2123 	/*
2124 	 * coalesce with right XAD
2125 	 */
2126       coalesceRight:		/* (xoff <= nxoff) */
2127 	/* is XAD last entry of page ? */
2128 	if (newindex == nextindex) {
2129 		if (xoff == nxoff)
2130 			goto out;
2131 		goto updateRight;
2132 	}
2133 
2134 	/* is nXAD logically and physically contiguous with rXAD ? */
2135 	rxad = &p->xad[index + 1];
2136 	rxlen = lengthXAD(rxad);
2137 	if (!(rxad->flag & XAD_NOTRECORDED) &&
2138 	    (nxoff + nxlen == offsetXAD(rxad)) &&
2139 	    (nxaddr + nxlen == addressXAD(rxad)) &&
2140 	    (rxlen + nxlen < MAXXLEN)) {
2141 		/* extend left rXAD */
2142 		XADoffset(rxad, nxoff);
2143 		XADlength(rxad, rxlen + nxlen);
2144 		XADaddress(rxad, nxaddr);
2145 
2146 		/* If we just merged two extents together, need to make sure
2147 		 * the left extent gets logged.  If the right one is marked
2148 		 * XAD_NEW, then we know it will be logged.  Otherwise, mark as
2149 		 * XAD_EXTENDED
2150 		 */
2151 		if (!(rxad->flag & XAD_NEW))
2152 			rxad->flag |= XAD_EXTENDED;
2153 
2154 		if (xlen > nxlen)
2155 			/* truncate XAD */
2156 			XADlength(xad, xlen - nxlen);
2157 		else {		/* (xlen == nxlen) */
2158 
2159 			/* remove XAD */
2160 			memmove(&p->xad[index], &p->xad[index + 1],
2161 				(nextindex - index - 1) << L2XTSLOTSIZE);
2162 
2163 			p->header.nextindex =
2164 			    cpu_to_le16(le16_to_cpu(p->header.nextindex) -
2165 					1);
2166 		}
2167 
2168 		goto out;
2169 	} else if (xoff == nxoff)
2170 		goto out;
2171 
2172 	if (xoff >= nxoff) {
2173 		XT_PUTPAGE(mp);
2174 		jfs_error(ip->i_sb, "xtUpdate: xoff >= nxoff");
2175 		return -EIO;
2176 	}
2177 /* #endif _JFS_WIP_COALESCE */
2178 
2179 	/*
2180 	 * split XAD into (lXAD, nXAD):
2181 	 *
2182 	 *          |---nXAD--->
2183 	 * --|----------XAD----------|--
2184 	 *   |-lXAD-|
2185 	 */
2186       updateRight:		/* (xoff < nxoff) */
2187 	/* truncate old XAD as lXAD:not_recorded */
2188 	xad = &p->xad[index];
2189 	XADlength(xad, nxoff - xoff);
2190 
2191 	/* insert nXAD:recorded */
2192 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
2193 
2194 		/* xtSpliUp() unpins leaf pages */
2195 		split.mp = mp;
2196 		split.index = newindex;
2197 		split.flag = xflag & ~XAD_NOTRECORDED;
2198 		split.off = nxoff;
2199 		split.len = nxlen;
2200 		split.addr = nxaddr;
2201 		split.pxdlist = NULL;
2202 		if ((rc = xtSplitUp(tid, ip, &split, &btstack)))
2203 			return rc;
2204 
2205 		/* get back old page */
2206 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
2207 		if (rc)
2208 			return rc;
2209 		/*
2210 		 * if leaf root has been split, original root has been
2211 		 * copied to new child page, i.e., original entry now
2212 		 * resides on the new child page;
2213 		 */
2214 		if (p->header.flag & BT_INTERNAL) {
2215 			ASSERT(p->header.nextindex ==
2216 			       cpu_to_le16(XTENTRYSTART + 1));
2217 			xad = &p->xad[XTENTRYSTART];
2218 			bn = addressXAD(xad);
2219 			XT_PUTPAGE(mp);
2220 
2221 			/* get new child page */
2222 			XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
2223 			if (rc)
2224 				return rc;
2225 
2226 			BT_MARK_DIRTY(mp, ip);
2227 			if (!test_cflag(COMMIT_Nolink, ip)) {
2228 				tlck = txLock(tid, ip, mp, tlckXTREE|tlckGROW);
2229 				xtlck = (struct xtlock *) & tlck->lock;
2230 			}
2231 		} else {
2232 			/* is nXAD on new page ? */
2233 			if (newindex >
2234 			    (le16_to_cpu(p->header.maxentry) >> 1)) {
2235 				newindex =
2236 				    newindex -
2237 				    le16_to_cpu(p->header.nextindex) +
2238 				    XTENTRYSTART;
2239 				newpage = 1;
2240 			}
2241 		}
2242 	} else {
2243 		/* if insert into middle, shift right remaining entries */
2244 		if (newindex < nextindex)
2245 			memmove(&p->xad[newindex + 1], &p->xad[newindex],
2246 				(nextindex - newindex) << L2XTSLOTSIZE);
2247 
2248 		/* insert the entry */
2249 		xad = &p->xad[newindex];
2250 		*xad = *nxad;
2251 		xad->flag = xflag & ~XAD_NOTRECORDED;
2252 
2253 		/* advance next available entry index. */
2254 		p->header.nextindex =
2255 		    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
2256 	}
2257 
2258 	/*
2259 	 * does nXAD force 3-way split ?
2260 	 *
2261 	 *          |---nXAD--->|
2262 	 * --|----------XAD-------------|--
2263 	 *   |-lXAD-|           |-rXAD -|
2264 	 */
2265 	if (nxoff + nxlen == xoff + xlen)
2266 		goto out;
2267 
2268 	/* reorient nXAD as XAD for further split XAD into (nXAD, rXAD) */
2269 	if (newpage) {
2270 		/* close out old page */
2271 		if (!test_cflag(COMMIT_Nolink, ip)) {
2272 			xtlck->lwm.offset = (xtlck->lwm.offset) ?
2273 			    min(index0, (int)xtlck->lwm.offset) : index0;
2274 			xtlck->lwm.length =
2275 			    le16_to_cpu(p->header.nextindex) -
2276 			    xtlck->lwm.offset;
2277 		}
2278 
2279 		bn = le64_to_cpu(p->header.next);
2280 		XT_PUTPAGE(mp);
2281 
2282 		/* get new right page */
2283 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
2284 		if (rc)
2285 			return rc;
2286 
2287 		BT_MARK_DIRTY(mp, ip);
2288 		if (!test_cflag(COMMIT_Nolink, ip)) {
2289 			tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
2290 			xtlck = (struct xtlock *) & tlck->lock;
2291 		}
2292 
2293 		index0 = index = newindex;
2294 	} else
2295 		index++;
2296 
2297 	newindex = index + 1;
2298 	nextindex = le16_to_cpu(p->header.nextindex);
2299 	xlen = xlen - (nxoff - xoff);
2300 	xoff = nxoff;
2301 	xaddr = nxaddr;
2302 
2303 	/* recompute split pages */
2304 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
2305 		XT_PUTPAGE(mp);
2306 
2307 		if ((rc = xtSearch(ip, nxoff, NULL, &cmp, &btstack, XT_INSERT)))
2308 			return rc;
2309 
2310 		/* retrieve search result */
2311 		XT_GETSEARCH(ip, btstack.top, bn, mp, p, index0);
2312 
2313 		if (cmp != 0) {
2314 			XT_PUTPAGE(mp);
2315 			jfs_error(ip->i_sb, "xtUpdate: xtSearch failed");
2316 			return -EIO;
2317 		}
2318 
2319 		if (index0 != index) {
2320 			XT_PUTPAGE(mp);
2321 			jfs_error(ip->i_sb,
2322 				  "xtUpdate: unexpected value of index");
2323 			return -EIO;
2324 		}
2325 	}
2326 
2327 	/*
2328 	 * split XAD into (nXAD, rXAD)
2329 	 *
2330 	 *          ---nXAD---|
2331 	 * --|----------XAD----------|--
2332 	 *                    |-rXAD-|
2333 	 */
2334       updateLeft:		/* (nxoff == xoff) && (nxlen < xlen) */
2335 	/* update old XAD with nXAD:recorded */
2336 	xad = &p->xad[index];
2337 	*xad = *nxad;
2338 	xad->flag = xflag & ~XAD_NOTRECORDED;
2339 
2340 	/* insert rXAD:not_recorded */
2341 	xoff = xoff + nxlen;
2342 	xlen = xlen - nxlen;
2343 	xaddr = xaddr + nxlen;
2344 	if (nextindex == le16_to_cpu(p->header.maxentry)) {
2345 /*
2346 printf("xtUpdate.updateLeft.split p:0x%p\n", p);
2347 */
2348 		/* xtSpliUp() unpins leaf pages */
2349 		split.mp = mp;
2350 		split.index = newindex;
2351 		split.flag = xflag;
2352 		split.off = xoff;
2353 		split.len = xlen;
2354 		split.addr = xaddr;
2355 		split.pxdlist = NULL;
2356 		if ((rc = xtSplitUp(tid, ip, &split, &btstack)))
2357 			return rc;
2358 
2359 		/* get back old page */
2360 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
2361 		if (rc)
2362 			return rc;
2363 
2364 		/*
2365 		 * if leaf root has been split, original root has been
2366 		 * copied to new child page, i.e., original entry now
2367 		 * resides on the new child page;
2368 		 */
2369 		if (p->header.flag & BT_INTERNAL) {
2370 			ASSERT(p->header.nextindex ==
2371 			       cpu_to_le16(XTENTRYSTART + 1));
2372 			xad = &p->xad[XTENTRYSTART];
2373 			bn = addressXAD(xad);
2374 			XT_PUTPAGE(mp);
2375 
2376 			/* get new child page */
2377 			XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
2378 			if (rc)
2379 				return rc;
2380 
2381 			BT_MARK_DIRTY(mp, ip);
2382 			if (!test_cflag(COMMIT_Nolink, ip)) {
2383 				tlck = txLock(tid, ip, mp, tlckXTREE|tlckGROW);
2384 				xtlck = (struct xtlock *) & tlck->lock;
2385 			}
2386 		}
2387 	} else {
2388 		/* if insert into middle, shift right remaining entries */
2389 		if (newindex < nextindex)
2390 			memmove(&p->xad[newindex + 1], &p->xad[newindex],
2391 				(nextindex - newindex) << L2XTSLOTSIZE);
2392 
2393 		/* insert the entry */
2394 		xad = &p->xad[newindex];
2395 		XT_PUTENTRY(xad, xflag, xoff, xlen, xaddr);
2396 
2397 		/* advance next available entry index. */
2398 		p->header.nextindex =
2399 		    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
2400 	}
2401 
2402       out:
2403 	if (!test_cflag(COMMIT_Nolink, ip)) {
2404 		xtlck->lwm.offset = (xtlck->lwm.offset) ?
2405 		    min(index0, (int)xtlck->lwm.offset) : index0;
2406 		xtlck->lwm.length = le16_to_cpu(p->header.nextindex) -
2407 		    xtlck->lwm.offset;
2408 	}
2409 
2410 	/* unpin the leaf page */
2411 	XT_PUTPAGE(mp);
2412 
2413 	return rc;
2414 }
2415 
2416 
2417 /*
2418  *	xtAppend()
2419  *
2420  * function: grow in append mode from contiguous region specified ;
2421  *
2422  * parameter:
2423  *	tid		- transaction id;
2424  *	ip		- file object;
2425  *	xflag		- extent flag:
2426  *	xoff		- extent offset;
2427  *	maxblocks	- max extent length;
2428  *	xlen		- extent length (in/out);
2429  *	xaddrp		- extent address pointer (in/out):
2430  *	flag		-
2431  *
2432  * return:
2433  */
2434 int xtAppend(tid_t tid,		/* transaction id */
2435 	     struct inode *ip, int xflag, s64 xoff, s32 maxblocks,
2436 	     s32 * xlenp,	/* (in/out) */
2437 	     s64 * xaddrp,	/* (in/out) */
2438 	     int flag)
2439 {
2440 	int rc = 0;
2441 	struct metapage *mp;	/* meta-page buffer */
2442 	xtpage_t *p;		/* base B+-tree index page */
2443 	s64 bn, xaddr;
2444 	int index, nextindex;
2445 	struct btstack btstack;	/* traverse stack */
2446 	struct xtsplit split;	/* split information */
2447 	xad_t *xad;
2448 	int cmp;
2449 	struct tlock *tlck;
2450 	struct xtlock *xtlck;
2451 	int nsplit, nblocks, xlen;
2452 	struct pxdlist pxdlist;
2453 	pxd_t *pxd;
2454 	s64 next;
2455 
2456 	xaddr = *xaddrp;
2457 	xlen = *xlenp;
2458 	jfs_info("xtAppend: xoff:0x%lx maxblocks:%d xlen:%d xaddr:0x%lx",
2459 		 (ulong) xoff, maxblocks, xlen, (ulong) xaddr);
2460 
2461 	/*
2462 	 *	search for the entry location at which to insert:
2463 	 *
2464 	 * xtFastSearch() and xtSearch() both returns (leaf page
2465 	 * pinned, index at which to insert).
2466 	 * n.b. xtSearch() may return index of maxentry of
2467 	 * the full page.
2468 	 */
2469 	if ((rc = xtSearch(ip, xoff, &next, &cmp, &btstack, XT_INSERT)))
2470 		return rc;
2471 
2472 	/* retrieve search result */
2473 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
2474 
2475 	if (cmp == 0) {
2476 		rc = -EEXIST;
2477 		goto out;
2478 	}
2479 
2480 	if (next)
2481 		xlen = min(xlen, (int)(next - xoff));
2482 //insert:
2483 	/*
2484 	 *	insert entry for new extent
2485 	 */
2486 	xflag |= XAD_NEW;
2487 
2488 	/*
2489 	 *	if the leaf page is full, split the page and
2490 	 *	propagate up the router entry for the new page from split
2491 	 *
2492 	 * The xtSplitUp() will insert the entry and unpin the leaf page.
2493 	 */
2494 	nextindex = le16_to_cpu(p->header.nextindex);
2495 	if (nextindex < le16_to_cpu(p->header.maxentry))
2496 		goto insertLeaf;
2497 
2498 	/*
2499 	 * allocate new index blocks to cover index page split(s)
2500 	 */
2501 	nsplit = btstack.nsplit;
2502 	split.pxdlist = &pxdlist;
2503 	pxdlist.maxnpxd = pxdlist.npxd = 0;
2504 	pxd = &pxdlist.pxd[0];
2505 	nblocks = JFS_SBI(ip->i_sb)->nbperpage;
2506 	for (; nsplit > 0; nsplit--, pxd++, xaddr += nblocks, maxblocks -= nblocks) {
2507 		if ((rc = dbAllocBottomUp(ip, xaddr, (s64) nblocks)) == 0) {
2508 			PXDaddress(pxd, xaddr);
2509 			PXDlength(pxd, nblocks);
2510 
2511 			pxdlist.maxnpxd++;
2512 
2513 			continue;
2514 		}
2515 
2516 		/* undo allocation */
2517 
2518 		goto out;
2519 	}
2520 
2521 	xlen = min(xlen, maxblocks);
2522 
2523 	/*
2524 	 * allocate data extent requested
2525 	 */
2526 	if ((rc = dbAllocBottomUp(ip, xaddr, (s64) xlen)))
2527 		goto out;
2528 
2529 	split.mp = mp;
2530 	split.index = index;
2531 	split.flag = xflag;
2532 	split.off = xoff;
2533 	split.len = xlen;
2534 	split.addr = xaddr;
2535 	if ((rc = xtSplitUp(tid, ip, &split, &btstack))) {
2536 		/* undo data extent allocation */
2537 		dbFree(ip, *xaddrp, (s64) * xlenp);
2538 
2539 		return rc;
2540 	}
2541 
2542 	*xaddrp = xaddr;
2543 	*xlenp = xlen;
2544 	return 0;
2545 
2546 	/*
2547 	 *	insert the new entry into the leaf page
2548 	 */
2549       insertLeaf:
2550 	/*
2551 	 * allocate data extent requested
2552 	 */
2553 	if ((rc = dbAllocBottomUp(ip, xaddr, (s64) xlen)))
2554 		goto out;
2555 
2556 	BT_MARK_DIRTY(mp, ip);
2557 	/*
2558 	 * acquire a transaction lock on the leaf page;
2559 	 *
2560 	 * action: xad insertion/extension;
2561 	 */
2562 	tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
2563 	xtlck = (struct xtlock *) & tlck->lock;
2564 
2565 	/* insert the new entry: mark the entry NEW */
2566 	xad = &p->xad[index];
2567 	XT_PUTENTRY(xad, xflag, xoff, xlen, xaddr);
2568 
2569 	/* advance next available entry index */
2570 	p->header.nextindex =
2571 	    cpu_to_le16(le16_to_cpu(p->header.nextindex) + 1);
2572 
2573 	xtlck->lwm.offset =
2574 	    (xtlck->lwm.offset) ? min(index,(int) xtlck->lwm.offset) : index;
2575 	xtlck->lwm.length = le16_to_cpu(p->header.nextindex) -
2576 	    xtlck->lwm.offset;
2577 
2578 	*xaddrp = xaddr;
2579 	*xlenp = xlen;
2580 
2581       out:
2582 	/* unpin the leaf page */
2583 	XT_PUTPAGE(mp);
2584 
2585 	return rc;
2586 }
2587 #ifdef _STILL_TO_PORT
2588 
2589 /* - TBD for defragmentaion/reorganization -
2590  *
2591  *	xtDelete()
2592  *
2593  * function:
2594  *	delete the entry with the specified key.
2595  *
2596  *	N.B.: whole extent of the entry is assumed to be deleted.
2597  *
2598  * parameter:
2599  *
2600  * return:
2601  *	ENOENT: if the entry is not found.
2602  *
2603  * exception:
2604  */
2605 int xtDelete(tid_t tid, struct inode *ip, s64 xoff, s32 xlen, int flag)
2606 {
2607 	int rc = 0;
2608 	struct btstack btstack;
2609 	int cmp;
2610 	s64 bn;
2611 	struct metapage *mp;
2612 	xtpage_t *p;
2613 	int index, nextindex;
2614 	struct tlock *tlck;
2615 	struct xtlock *xtlck;
2616 
2617 	/*
2618 	 * find the matching entry; xtSearch() pins the page
2619 	 */
2620 	if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0)))
2621 		return rc;
2622 
2623 	XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
2624 	if (cmp) {
2625 		/* unpin the leaf page */
2626 		XT_PUTPAGE(mp);
2627 		return -ENOENT;
2628 	}
2629 
2630 	/*
2631 	 * delete the entry from the leaf page
2632 	 */
2633 	nextindex = le16_to_cpu(p->header.nextindex);
2634 	p->header.nextindex =
2635 	    cpu_to_le16(le16_to_cpu(p->header.nextindex) - 1);
2636 
2637 	/*
2638 	 * if the leaf page bocome empty, free the page
2639 	 */
2640 	if (p->header.nextindex == cpu_to_le16(XTENTRYSTART))
2641 		return (xtDeleteUp(tid, ip, mp, p, &btstack));
2642 
2643 	BT_MARK_DIRTY(mp, ip);
2644 	/*
2645 	 * acquire a transaction lock on the leaf page;
2646 	 *
2647 	 * action:xad deletion;
2648 	 */
2649 	tlck = txLock(tid, ip, mp, tlckXTREE);
2650 	xtlck = (struct xtlock *) & tlck->lock;
2651 	xtlck->lwm.offset =
2652 	    (xtlck->lwm.offset) ? min(index, xtlck->lwm.offset) : index;
2653 
2654 	/* if delete from middle, shift left/compact the remaining entries */
2655 	if (index < nextindex - 1)
2656 		memmove(&p->xad[index], &p->xad[index + 1],
2657 			(nextindex - index - 1) * sizeof(xad_t));
2658 
2659 	XT_PUTPAGE(mp);
2660 
2661 	return 0;
2662 }
2663 
2664 
2665 /* - TBD for defragmentaion/reorganization -
2666  *
2667  *	xtDeleteUp()
2668  *
2669  * function:
2670  *	free empty pages as propagating deletion up the tree
2671  *
2672  * parameter:
2673  *
2674  * return:
2675  */
2676 static int
2677 xtDeleteUp(tid_t tid, struct inode *ip,
2678 	   struct metapage * fmp, xtpage_t * fp, struct btstack * btstack)
2679 {
2680 	int rc = 0;
2681 	struct metapage *mp;
2682 	xtpage_t *p;
2683 	int index, nextindex;
2684 	s64 xaddr;
2685 	int xlen;
2686 	struct btframe *parent;
2687 	struct tlock *tlck;
2688 	struct xtlock *xtlck;
2689 
2690 	/*
2691 	 * keep root leaf page which has become empty
2692 	 */
2693 	if (fp->header.flag & BT_ROOT) {
2694 		/* keep the root page */
2695 		fp->header.flag &= ~BT_INTERNAL;
2696 		fp->header.flag |= BT_LEAF;
2697 		fp->header.nextindex = cpu_to_le16(XTENTRYSTART);
2698 
2699 		/* XT_PUTPAGE(fmp); */
2700 
2701 		return 0;
2702 	}
2703 
2704 	/*
2705 	 * free non-root leaf page
2706 	 */
2707 	if ((rc = xtRelink(tid, ip, fp))) {
2708 		XT_PUTPAGE(fmp);
2709 		return rc;
2710 	}
2711 
2712 	xaddr = addressPXD(&fp->header.self);
2713 	xlen = lengthPXD(&fp->header.self);
2714 	/* free the page extent */
2715 	dbFree(ip, xaddr, (s64) xlen);
2716 
2717 	/* free the buffer page */
2718 	discard_metapage(fmp);
2719 
2720 	/*
2721 	 * propagate page deletion up the index tree
2722 	 *
2723 	 * If the delete from the parent page makes it empty,
2724 	 * continue all the way up the tree.
2725 	 * stop if the root page is reached (which is never deleted) or
2726 	 * if the entry deletion does not empty the page.
2727 	 */
2728 	while ((parent = BT_POP(btstack)) != NULL) {
2729 		/* get/pin the parent page <sp> */
2730 		XT_GETPAGE(ip, parent->bn, mp, PSIZE, p, rc);
2731 		if (rc)
2732 			return rc;
2733 
2734 		index = parent->index;
2735 
2736 		/* delete the entry for the freed child page from parent.
2737 		 */
2738 		nextindex = le16_to_cpu(p->header.nextindex);
2739 
2740 		/*
2741 		 * the parent has the single entry being deleted:
2742 		 * free the parent page which has become empty.
2743 		 */
2744 		if (nextindex == 1) {
2745 			if (p->header.flag & BT_ROOT) {
2746 				/* keep the root page */
2747 				p->header.flag &= ~BT_INTERNAL;
2748 				p->header.flag |= BT_LEAF;
2749 				p->header.nextindex =
2750 				    cpu_to_le16(XTENTRYSTART);
2751 
2752 				/* XT_PUTPAGE(mp); */
2753 
2754 				break;
2755 			} else {
2756 				/* free the parent page */
2757 				if ((rc = xtRelink(tid, ip, p)))
2758 					return rc;
2759 
2760 				xaddr = addressPXD(&p->header.self);
2761 				/* free the page extent */
2762 				dbFree(ip, xaddr,
2763 				       (s64) JFS_SBI(ip->i_sb)->nbperpage);
2764 
2765 				/* unpin/free the buffer page */
2766 				discard_metapage(mp);
2767 
2768 				/* propagate up */
2769 				continue;
2770 			}
2771 		}
2772 		/*
2773 		 * the parent has other entries remaining:
2774 		 * delete the router entry from the parent page.
2775 		 */
2776 		else {
2777 			BT_MARK_DIRTY(mp, ip);
2778 			/*
2779 			 * acquire a transaction lock on the leaf page;
2780 			 *
2781 			 * action:xad deletion;
2782 			 */
2783 			tlck = txLock(tid, ip, mp, tlckXTREE);
2784 			xtlck = (struct xtlock *) & tlck->lock;
2785 			xtlck->lwm.offset =
2786 			    (xtlck->lwm.offset) ? min(index,
2787 						      xtlck->lwm.
2788 						      offset) : index;
2789 
2790 			/* if delete from middle,
2791 			 * shift left/compact the remaining entries in the page
2792 			 */
2793 			if (index < nextindex - 1)
2794 				memmove(&p->xad[index], &p->xad[index + 1],
2795 					(nextindex - index -
2796 					 1) << L2XTSLOTSIZE);
2797 
2798 			p->header.nextindex =
2799 			    cpu_to_le16(le16_to_cpu(p->header.nextindex) -
2800 					1);
2801 			jfs_info("xtDeleteUp(entry): 0x%lx[%d]",
2802 				 (ulong) parent->bn, index);
2803 		}
2804 
2805 		/* unpin the parent page */
2806 		XT_PUTPAGE(mp);
2807 
2808 		/* exit propagation up */
2809 		break;
2810 	}
2811 
2812 	return 0;
2813 }
2814 
2815 
2816 /*
2817  * NAME:	xtRelocate()
2818  *
2819  * FUNCTION:	relocate xtpage or data extent of regular file;
2820  *		This function is mainly used by defragfs utility.
2821  *
2822  * NOTE:	This routine does not have the logic to handle
2823  *		uncommitted allocated extent. The caller should call
2824  *		txCommit() to commit all the allocation before call
2825  *		this routine.
2826  */
2827 int
2828 xtRelocate(tid_t tid, struct inode * ip, xad_t * oxad,	/* old XAD */
2829 	   s64 nxaddr,		/* new xaddr */
2830 	   int xtype)
2831 {				/* extent type: XTPAGE or DATAEXT */
2832 	int rc = 0;
2833 	struct tblock *tblk;
2834 	struct tlock *tlck;
2835 	struct xtlock *xtlck;
2836 	struct metapage *mp, *pmp, *lmp, *rmp;	/* meta-page buffer */
2837 	xtpage_t *p, *pp, *rp, *lp;	/* base B+-tree index page */
2838 	xad_t *xad;
2839 	pxd_t *pxd;
2840 	s64 xoff, xsize;
2841 	int xlen;
2842 	s64 oxaddr, sxaddr, dxaddr, nextbn, prevbn;
2843 	cbuf_t *cp;
2844 	s64 offset, nbytes, nbrd, pno;
2845 	int nb, npages, nblks;
2846 	s64 bn;
2847 	int cmp;
2848 	int index;
2849 	struct pxd_lock *pxdlock;
2850 	struct btstack btstack;	/* traverse stack */
2851 
2852 	xtype = xtype & EXTENT_TYPE;
2853 
2854 	xoff = offsetXAD(oxad);
2855 	oxaddr = addressXAD(oxad);
2856 	xlen = lengthXAD(oxad);
2857 
2858 	/* validate extent offset */
2859 	offset = xoff << JFS_SBI(ip->i_sb)->l2bsize;
2860 	if (offset >= ip->i_size)
2861 		return -ESTALE;	/* stale extent */
2862 
2863 	jfs_info("xtRelocate: xtype:%d xoff:0x%lx xlen:0x%x xaddr:0x%lx:0x%lx",
2864 		 xtype, (ulong) xoff, xlen, (ulong) oxaddr, (ulong) nxaddr);
2865 
2866 	/*
2867 	 *	1. get and validate the parent xtpage/xad entry
2868 	 *	covering the source extent to be relocated;
2869 	 */
2870 	if (xtype == DATAEXT) {
2871 		/* search in leaf entry */
2872 		rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0);
2873 		if (rc)
2874 			return rc;
2875 
2876 		/* retrieve search result */
2877 		XT_GETSEARCH(ip, btstack.top, bn, pmp, pp, index);
2878 
2879 		if (cmp) {
2880 			XT_PUTPAGE(pmp);
2881 			return -ESTALE;
2882 		}
2883 
2884 		/* validate for exact match with a single entry */
2885 		xad = &pp->xad[index];
2886 		if (addressXAD(xad) != oxaddr || lengthXAD(xad) != xlen) {
2887 			XT_PUTPAGE(pmp);
2888 			return -ESTALE;
2889 		}
2890 	} else {		/* (xtype == XTPAGE) */
2891 
2892 		/* search in internal entry */
2893 		rc = xtSearchNode(ip, oxad, &cmp, &btstack, 0);
2894 		if (rc)
2895 			return rc;
2896 
2897 		/* retrieve search result */
2898 		XT_GETSEARCH(ip, btstack.top, bn, pmp, pp, index);
2899 
2900 		if (cmp) {
2901 			XT_PUTPAGE(pmp);
2902 			return -ESTALE;
2903 		}
2904 
2905 		/* xtSearchNode() validated for exact match with a single entry
2906 		 */
2907 		xad = &pp->xad[index];
2908 	}
2909 	jfs_info("xtRelocate: parent xad entry validated.");
2910 
2911 	/*
2912 	 *	2. relocate the extent
2913 	 */
2914 	if (xtype == DATAEXT) {
2915 		/* if the extent is allocated-but-not-recorded
2916 		 * there is no real data to be moved in this extent,
2917 		 */
2918 		if (xad->flag & XAD_NOTRECORDED)
2919 			goto out;
2920 		else
2921 			/* release xtpage for cmRead()/xtLookup() */
2922 			XT_PUTPAGE(pmp);
2923 
2924 		/*
2925 		 *	cmRelocate()
2926 		 *
2927 		 * copy target data pages to be relocated;
2928 		 *
2929 		 * data extent must start at page boundary and
2930 		 * multiple of page size (except the last data extent);
2931 		 * read in each page of the source data extent into cbuf,
2932 		 * update the cbuf extent descriptor of the page to be
2933 		 * homeward bound to new dst data extent
2934 		 * copy the data from the old extent to new extent.
2935 		 * copy is essential for compressed files to avoid problems
2936 		 * that can arise if there was a change in compression
2937 		 * algorithms.
2938 		 * it is a good strategy because it may disrupt cache
2939 		 * policy to keep the pages in memory afterwards.
2940 		 */
2941 		offset = xoff << JFS_SBI(ip->i_sb)->l2bsize;
2942 		assert((offset & CM_OFFSET) == 0);
2943 		nbytes = xlen << JFS_SBI(ip->i_sb)->l2bsize;
2944 		pno = offset >> CM_L2BSIZE;
2945 		npages = (nbytes + (CM_BSIZE - 1)) >> CM_L2BSIZE;
2946 /*
2947 		npages = ((offset + nbytes - 1) >> CM_L2BSIZE) -
2948 			  (offset >> CM_L2BSIZE) + 1;
2949 */
2950 		sxaddr = oxaddr;
2951 		dxaddr = nxaddr;
2952 
2953 		/* process the request one cache buffer at a time */
2954 		for (nbrd = 0; nbrd < nbytes; nbrd += nb,
2955 		     offset += nb, pno++, npages--) {
2956 			/* compute page size */
2957 			nb = min(nbytes - nbrd, CM_BSIZE);
2958 
2959 			/* get the cache buffer of the page */
2960 			if (rc = cmRead(ip, offset, npages, &cp))
2961 				break;
2962 
2963 			assert(addressPXD(&cp->cm_pxd) == sxaddr);
2964 			assert(!cp->cm_modified);
2965 
2966 			/* bind buffer with the new extent address */
2967 			nblks = nb >> JFS_IP(ip->i_sb)->l2bsize;
2968 			cmSetXD(ip, cp, pno, dxaddr, nblks);
2969 
2970 			/* release the cbuf, mark it as modified */
2971 			cmPut(cp, true);
2972 
2973 			dxaddr += nblks;
2974 			sxaddr += nblks;
2975 		}
2976 
2977 		/* get back parent page */
2978 		if ((rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0)))
2979 			return rc;
2980 
2981 		XT_GETSEARCH(ip, btstack.top, bn, pmp, pp, index);
2982 		jfs_info("xtRelocate: target data extent relocated.");
2983 	} else {		/* (xtype == XTPAGE) */
2984 
2985 		/*
2986 		 * read in the target xtpage from the source extent;
2987 		 */
2988 		XT_GETPAGE(ip, oxaddr, mp, PSIZE, p, rc);
2989 		if (rc) {
2990 			XT_PUTPAGE(pmp);
2991 			return rc;
2992 		}
2993 
2994 		/*
2995 		 * read in sibling pages if any to update sibling pointers;
2996 		 */
2997 		rmp = NULL;
2998 		if (p->header.next) {
2999 			nextbn = le64_to_cpu(p->header.next);
3000 			XT_GETPAGE(ip, nextbn, rmp, PSIZE, rp, rc);
3001 			if (rc) {
3002 				XT_PUTPAGE(pmp);
3003 				XT_PUTPAGE(mp);
3004 				return (rc);
3005 			}
3006 		}
3007 
3008 		lmp = NULL;
3009 		if (p->header.prev) {
3010 			prevbn = le64_to_cpu(p->header.prev);
3011 			XT_GETPAGE(ip, prevbn, lmp, PSIZE, lp, rc);
3012 			if (rc) {
3013 				XT_PUTPAGE(pmp);
3014 				XT_PUTPAGE(mp);
3015 				if (rmp)
3016 					XT_PUTPAGE(rmp);
3017 				return (rc);
3018 			}
3019 		}
3020 
3021 		/* at this point, all xtpages to be updated are in memory */
3022 
3023 		/*
3024 		 * update sibling pointers of sibling xtpages if any;
3025 		 */
3026 		if (lmp) {
3027 			BT_MARK_DIRTY(lmp, ip);
3028 			tlck = txLock(tid, ip, lmp, tlckXTREE | tlckRELINK);
3029 			lp->header.next = cpu_to_le64(nxaddr);
3030 			XT_PUTPAGE(lmp);
3031 		}
3032 
3033 		if (rmp) {
3034 			BT_MARK_DIRTY(rmp, ip);
3035 			tlck = txLock(tid, ip, rmp, tlckXTREE | tlckRELINK);
3036 			rp->header.prev = cpu_to_le64(nxaddr);
3037 			XT_PUTPAGE(rmp);
3038 		}
3039 
3040 		/*
3041 		 * update the target xtpage to be relocated
3042 		 *
3043 		 * update the self address of the target page
3044 		 * and write to destination extent;
3045 		 * redo image covers the whole xtpage since it is new page
3046 		 * to the destination extent;
3047 		 * update of bmap for the free of source extent
3048 		 * of the target xtpage itself:
3049 		 * update of bmap for the allocation of destination extent
3050 		 * of the target xtpage itself:
3051 		 * update of bmap for the extents covered by xad entries in
3052 		 * the target xtpage is not necessary since they are not
3053 		 * updated;
3054 		 * if not committed before this relocation,
3055 		 * target page may contain XAD_NEW entries which must
3056 		 * be scanned for bmap update (logredo() always
3057 		 * scan xtpage REDOPAGE image for bmap update);
3058 		 * if committed before this relocation (tlckRELOCATE),
3059 		 * scan may be skipped by commit() and logredo();
3060 		 */
3061 		BT_MARK_DIRTY(mp, ip);
3062 		/* tlckNEW init xtlck->lwm.offset = XTENTRYSTART; */
3063 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckNEW);
3064 		xtlck = (struct xtlock *) & tlck->lock;
3065 
3066 		/* update the self address in the xtpage header */
3067 		pxd = &p->header.self;
3068 		PXDaddress(pxd, nxaddr);
3069 
3070 		/* linelock for the after image of the whole page */
3071 		xtlck->lwm.length =
3072 		    le16_to_cpu(p->header.nextindex) - xtlck->lwm.offset;
3073 
3074 		/* update the buffer extent descriptor of target xtpage */
3075 		xsize = xlen << JFS_SBI(ip->i_sb)->l2bsize;
3076 		bmSetXD(mp, nxaddr, xsize);
3077 
3078 		/* unpin the target page to new homeward bound */
3079 		XT_PUTPAGE(mp);
3080 		jfs_info("xtRelocate: target xtpage relocated.");
3081 	}
3082 
3083 	/*
3084 	 *	3. acquire maplock for the source extent to be freed;
3085 	 *
3086 	 * acquire a maplock saving the src relocated extent address;
3087 	 * to free of the extent at commit time;
3088 	 */
3089       out:
3090 	/* if DATAEXT relocation, write a LOG_UPDATEMAP record for
3091 	 * free PXD of the source data extent (logredo() will update
3092 	 * bmap for free of source data extent), and update bmap for
3093 	 * free of the source data extent;
3094 	 */
3095 	if (xtype == DATAEXT)
3096 		tlck = txMaplock(tid, ip, tlckMAP);
3097 	/* if XTPAGE relocation, write a LOG_NOREDOPAGE record
3098 	 * for the source xtpage (logredo() will init NoRedoPage
3099 	 * filter and will also update bmap for free of the source
3100 	 * xtpage), and update bmap for free of the source xtpage;
3101 	 * N.B. We use tlckMAP instead of tlkcXTREE because there
3102 	 *      is no buffer associated with this lock since the buffer
3103 	 *      has been redirected to the target location.
3104 	 */
3105 	else			/* (xtype == XTPAGE) */
3106 		tlck = txMaplock(tid, ip, tlckMAP | tlckRELOCATE);
3107 
3108 	pxdlock = (struct pxd_lock *) & tlck->lock;
3109 	pxdlock->flag = mlckFREEPXD;
3110 	PXDaddress(&pxdlock->pxd, oxaddr);
3111 	PXDlength(&pxdlock->pxd, xlen);
3112 	pxdlock->index = 1;
3113 
3114 	/*
3115 	 *	4. update the parent xad entry for relocation;
3116 	 *
3117 	 * acquire tlck for the parent entry with XAD_NEW as entry
3118 	 * update which will write LOG_REDOPAGE and update bmap for
3119 	 * allocation of XAD_NEW destination extent;
3120 	 */
3121 	jfs_info("xtRelocate: update parent xad entry.");
3122 	BT_MARK_DIRTY(pmp, ip);
3123 	tlck = txLock(tid, ip, pmp, tlckXTREE | tlckGROW);
3124 	xtlck = (struct xtlock *) & tlck->lock;
3125 
3126 	/* update the XAD with the new destination extent; */
3127 	xad = &pp->xad[index];
3128 	xad->flag |= XAD_NEW;
3129 	XADaddress(xad, nxaddr);
3130 
3131 	xtlck->lwm.offset = min(index, xtlck->lwm.offset);
3132 	xtlck->lwm.length = le16_to_cpu(pp->header.nextindex) -
3133 	    xtlck->lwm.offset;
3134 
3135 	/* unpin the parent xtpage */
3136 	XT_PUTPAGE(pmp);
3137 
3138 	return rc;
3139 }
3140 
3141 
3142 /*
3143  *	xtSearchNode()
3144  *
3145  * function:	search for the internal xad entry covering specified extent.
3146  *		This function is mainly used by defragfs utility.
3147  *
3148  * parameters:
3149  *	ip	- file object;
3150  *	xad	- extent to find;
3151  *	cmpp	- comparison result:
3152  *	btstack - traverse stack;
3153  *	flag	- search process flag;
3154  *
3155  * returns:
3156  *	btstack contains (bn, index) of search path traversed to the entry.
3157  *	*cmpp is set to result of comparison with the entry returned.
3158  *	the page containing the entry is pinned at exit.
3159  */
3160 static int xtSearchNode(struct inode *ip, xad_t * xad,	/* required XAD entry */
3161 			int *cmpp, struct btstack * btstack, int flag)
3162 {
3163 	int rc = 0;
3164 	s64 xoff, xaddr;
3165 	int xlen;
3166 	int cmp = 1;		/* init for empty page */
3167 	s64 bn;			/* block number */
3168 	struct metapage *mp;	/* meta-page buffer */
3169 	xtpage_t *p;		/* page */
3170 	int base, index, lim;
3171 	struct btframe *btsp;
3172 	s64 t64;
3173 
3174 	BT_CLR(btstack);
3175 
3176 	xoff = offsetXAD(xad);
3177 	xlen = lengthXAD(xad);
3178 	xaddr = addressXAD(xad);
3179 
3180 	/*
3181 	 *	search down tree from root:
3182 	 *
3183 	 * between two consecutive entries of <Ki, Pi> and <Kj, Pj> of
3184 	 * internal page, child page Pi contains entry with k, Ki <= K < Kj.
3185 	 *
3186 	 * if entry with search key K is not found
3187 	 * internal page search find the entry with largest key Ki
3188 	 * less than K which point to the child page to search;
3189 	 * leaf page search find the entry with smallest key Kj
3190 	 * greater than K so that the returned index is the position of
3191 	 * the entry to be shifted right for insertion of new entry.
3192 	 * for empty tree, search key is greater than any key of the tree.
3193 	 *
3194 	 * by convention, root bn = 0.
3195 	 */
3196 	for (bn = 0;;) {
3197 		/* get/pin the page to search */
3198 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
3199 		if (rc)
3200 			return rc;
3201 		if (p->header.flag & BT_LEAF) {
3202 			XT_PUTPAGE(mp);
3203 			return -ESTALE;
3204 		}
3205 
3206 		lim = le16_to_cpu(p->header.nextindex) - XTENTRYSTART;
3207 
3208 		/*
3209 		 * binary search with search key K on the current page
3210 		 */
3211 		for (base = XTENTRYSTART; lim; lim >>= 1) {
3212 			index = base + (lim >> 1);
3213 
3214 			XT_CMP(cmp, xoff, &p->xad[index], t64);
3215 			if (cmp == 0) {
3216 				/*
3217 				 *	search hit
3218 				 *
3219 				 * verify for exact match;
3220 				 */
3221 				if (xaddr == addressXAD(&p->xad[index]) &&
3222 				    xoff == offsetXAD(&p->xad[index])) {
3223 					*cmpp = cmp;
3224 
3225 					/* save search result */
3226 					btsp = btstack->top;
3227 					btsp->bn = bn;
3228 					btsp->index = index;
3229 					btsp->mp = mp;
3230 
3231 					return 0;
3232 				}
3233 
3234 				/* descend/search its child page */
3235 				goto next;
3236 			}
3237 
3238 			if (cmp > 0) {
3239 				base = index + 1;
3240 				--lim;
3241 			}
3242 		}
3243 
3244 		/*
3245 		 *	search miss - non-leaf page:
3246 		 *
3247 		 * base is the smallest index with key (Kj) greater than
3248 		 * search key (K) and may be zero or maxentry index.
3249 		 * if base is non-zero, decrement base by one to get the parent
3250 		 * entry of the child page to search.
3251 		 */
3252 		index = base ? base - 1 : base;
3253 
3254 		/*
3255 		 * go down to child page
3256 		 */
3257 	      next:
3258 		/* get the child page block number */
3259 		bn = addressXAD(&p->xad[index]);
3260 
3261 		/* unpin the parent page */
3262 		XT_PUTPAGE(mp);
3263 	}
3264 }
3265 
3266 
3267 /*
3268  *	xtRelink()
3269  *
3270  * function:
3271  *	link around a freed page.
3272  *
3273  * Parameter:
3274  *	int		tid,
3275  *	struct inode	*ip,
3276  *	xtpage_t	*p)
3277  *
3278  * returns:
3279  */
3280 static int xtRelink(tid_t tid, struct inode *ip, xtpage_t * p)
3281 {
3282 	int rc = 0;
3283 	struct metapage *mp;
3284 	s64 nextbn, prevbn;
3285 	struct tlock *tlck;
3286 
3287 	nextbn = le64_to_cpu(p->header.next);
3288 	prevbn = le64_to_cpu(p->header.prev);
3289 
3290 	/* update prev pointer of the next page */
3291 	if (nextbn != 0) {
3292 		XT_GETPAGE(ip, nextbn, mp, PSIZE, p, rc);
3293 		if (rc)
3294 			return rc;
3295 
3296 		/*
3297 		 * acquire a transaction lock on the page;
3298 		 *
3299 		 * action: update prev pointer;
3300 		 */
3301 		BT_MARK_DIRTY(mp, ip);
3302 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckRELINK);
3303 
3304 		/* the page may already have been tlock'd */
3305 
3306 		p->header.prev = cpu_to_le64(prevbn);
3307 
3308 		XT_PUTPAGE(mp);
3309 	}
3310 
3311 	/* update next pointer of the previous page */
3312 	if (prevbn != 0) {
3313 		XT_GETPAGE(ip, prevbn, mp, PSIZE, p, rc);
3314 		if (rc)
3315 			return rc;
3316 
3317 		/*
3318 		 * acquire a transaction lock on the page;
3319 		 *
3320 		 * action: update next pointer;
3321 		 */
3322 		BT_MARK_DIRTY(mp, ip);
3323 		tlck = txLock(tid, ip, mp, tlckXTREE | tlckRELINK);
3324 
3325 		/* the page may already have been tlock'd */
3326 
3327 		p->header.next = le64_to_cpu(nextbn);
3328 
3329 		XT_PUTPAGE(mp);
3330 	}
3331 
3332 	return 0;
3333 }
3334 #endif				/*  _STILL_TO_PORT */
3335 
3336 
3337 /*
3338  *	xtInitRoot()
3339  *
3340  * initialize file root (inline in inode)
3341  */
3342 void xtInitRoot(tid_t tid, struct inode *ip)
3343 {
3344 	xtpage_t *p;
3345 
3346 	/*
3347 	 * acquire a transaction lock on the root
3348 	 *
3349 	 * action:
3350 	 */
3351 	txLock(tid, ip, (struct metapage *) &JFS_IP(ip)->bxflag,
3352 		      tlckXTREE | tlckNEW);
3353 	p = &JFS_IP(ip)->i_xtroot;
3354 
3355 	p->header.flag = DXD_INDEX | BT_ROOT | BT_LEAF;
3356 	p->header.nextindex = cpu_to_le16(XTENTRYSTART);
3357 
3358 	if (S_ISDIR(ip->i_mode))
3359 		p->header.maxentry = cpu_to_le16(XTROOTINITSLOT_DIR);
3360 	else {
3361 		p->header.maxentry = cpu_to_le16(XTROOTINITSLOT);
3362 		ip->i_size = 0;
3363 	}
3364 
3365 
3366 	return;
3367 }
3368 
3369 
3370 /*
3371  * We can run into a deadlock truncating a file with a large number of
3372  * xtree pages (large fragmented file).  A robust fix would entail a
3373  * reservation system where we would reserve a number of metadata pages
3374  * and tlocks which we would be guaranteed without a deadlock.  Without
3375  * this, a partial fix is to limit number of metadata pages we will lock
3376  * in a single transaction.  Currently we will truncate the file so that
3377  * no more than 50 leaf pages will be locked.  The caller of xtTruncate
3378  * will be responsible for ensuring that the current transaction gets
3379  * committed, and that subsequent transactions are created to truncate
3380  * the file further if needed.
3381  */
3382 #define MAX_TRUNCATE_LEAVES 50
3383 
3384 /*
3385  *	xtTruncate()
3386  *
3387  * function:
3388  *	traverse for truncation logging backward bottom up;
3389  *	terminate at the last extent entry at the current subtree
3390  *	root page covering new down size.
3391  *	truncation may occur within the last extent entry.
3392  *
3393  * parameter:
3394  *	int		tid,
3395  *	struct inode	*ip,
3396  *	s64		newsize,
3397  *	int		type)	{PWMAP, PMAP, WMAP; DELETE, TRUNCATE}
3398  *
3399  * return:
3400  *
3401  * note:
3402  *	PWMAP:
3403  *	 1. truncate (non-COMMIT_NOLINK file)
3404  *	    by jfs_truncate() or jfs_open(O_TRUNC):
3405  *	    xtree is updated;
3406  *	 2. truncate index table of directory when last entry removed
3407  *	map update via tlock at commit time;
3408  *	PMAP:
3409  *	 Call xtTruncate_pmap instead
3410  *	WMAP:
3411  *	 1. remove (free zero link count) on last reference release
3412  *	    (pmap has been freed at commit zero link count);
3413  *	 2. truncate (COMMIT_NOLINK file, i.e., tmp file):
3414  *	    xtree is updated;
3415  *	 map update directly at truncation time;
3416  *
3417  *	if (DELETE)
3418  *		no LOG_NOREDOPAGE is required (NOREDOFILE is sufficient);
3419  *	else if (TRUNCATE)
3420  *		must write LOG_NOREDOPAGE for deleted index page;
3421  *
3422  * pages may already have been tlocked by anonymous transactions
3423  * during file growth (i.e., write) before truncation;
3424  *
3425  * except last truncated entry, deleted entries remains as is
3426  * in the page (nextindex is updated) for other use
3427  * (e.g., log/update allocation map): this avoid copying the page
3428  * info but delay free of pages;
3429  *
3430  */
3431 s64 xtTruncate(tid_t tid, struct inode *ip, s64 newsize, int flag)
3432 {
3433 	int rc = 0;
3434 	s64 teof;
3435 	struct metapage *mp;
3436 	xtpage_t *p;
3437 	s64 bn;
3438 	int index, nextindex;
3439 	xad_t *xad;
3440 	s64 xoff, xaddr;
3441 	int xlen, len, freexlen;
3442 	struct btstack btstack;
3443 	struct btframe *parent;
3444 	struct tblock *tblk = NULL;
3445 	struct tlock *tlck = NULL;
3446 	struct xtlock *xtlck = NULL;
3447 	struct xdlistlock xadlock;	/* maplock for COMMIT_WMAP */
3448 	struct pxd_lock *pxdlock;		/* maplock for COMMIT_WMAP */
3449 	s64 nfreed;
3450 	int freed, log;
3451 	int locked_leaves = 0;
3452 
3453 	/* save object truncation type */
3454 	if (tid) {
3455 		tblk = tid_to_tblock(tid);
3456 		tblk->xflag |= flag;
3457 	}
3458 
3459 	nfreed = 0;
3460 
3461 	flag &= COMMIT_MAP;
3462 	assert(flag != COMMIT_PMAP);
3463 
3464 	if (flag == COMMIT_PWMAP)
3465 		log = 1;
3466 	else {
3467 		log = 0;
3468 		xadlock.flag = mlckFREEXADLIST;
3469 		xadlock.index = 1;
3470 	}
3471 
3472 	/*
3473 	 * if the newsize is not an integral number of pages,
3474 	 * the file between newsize and next page boundary will
3475 	 * be cleared.
3476 	 * if truncating into a file hole, it will cause
3477 	 * a full block to be allocated for the logical block.
3478 	 */
3479 
3480 	/*
3481 	 * release page blocks of truncated region <teof, eof>
3482 	 *
3483 	 * free the data blocks from the leaf index blocks.
3484 	 * delete the parent index entries corresponding to
3485 	 * the freed child data/index blocks.
3486 	 * free the index blocks themselves which aren't needed
3487 	 * in new sized file.
3488 	 *
3489 	 * index blocks are updated only if the blocks are to be
3490 	 * retained in the new sized file.
3491 	 * if type is PMAP, the data and index pages are NOT
3492 	 * freed, and the data and index blocks are NOT freed
3493 	 * from working map.
3494 	 * (this will allow continued access of data/index of
3495 	 * temporary file (zerolink count file truncated to zero-length)).
3496 	 */
3497 	teof = (newsize + (JFS_SBI(ip->i_sb)->bsize - 1)) >>
3498 	    JFS_SBI(ip->i_sb)->l2bsize;
3499 
3500 	/* clear stack */
3501 	BT_CLR(&btstack);
3502 
3503 	/*
3504 	 * start with root
3505 	 *
3506 	 * root resides in the inode
3507 	 */
3508 	bn = 0;
3509 
3510 	/*
3511 	 * first access of each page:
3512 	 */
3513       getPage:
3514 	XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
3515 	if (rc)
3516 		return rc;
3517 
3518 	/* process entries backward from last index */
3519 	index = le16_to_cpu(p->header.nextindex) - 1;
3520 
3521 
3522 	/* Since this is the rightmost page at this level, and we may have
3523 	 * already freed a page that was formerly to the right, let's make
3524 	 * sure that the next pointer is zero.
3525 	 */
3526 	if (p->header.next) {
3527 		if (log)
3528 			/*
3529 			 * Make sure this change to the header is logged.
3530 			 * If we really truncate this leaf, the flag
3531 			 * will be changed to tlckTRUNCATE
3532 			 */
3533 			tlck = txLock(tid, ip, mp, tlckXTREE|tlckGROW);
3534 		BT_MARK_DIRTY(mp, ip);
3535 		p->header.next = 0;
3536 	}
3537 
3538 	if (p->header.flag & BT_INTERNAL)
3539 		goto getChild;
3540 
3541 	/*
3542 	 *	leaf page
3543 	 */
3544 	freed = 0;
3545 
3546 	/* does region covered by leaf page precede Teof ? */
3547 	xad = &p->xad[index];
3548 	xoff = offsetXAD(xad);
3549 	xlen = lengthXAD(xad);
3550 	if (teof >= xoff + xlen) {
3551 		XT_PUTPAGE(mp);
3552 		goto getParent;
3553 	}
3554 
3555 	/* (re)acquire tlock of the leaf page */
3556 	if (log) {
3557 		if (++locked_leaves > MAX_TRUNCATE_LEAVES) {
3558 			/*
3559 			 * We need to limit the size of the transaction
3560 			 * to avoid exhausting pagecache & tlocks
3561 			 */
3562 			XT_PUTPAGE(mp);
3563 			newsize = (xoff + xlen) << JFS_SBI(ip->i_sb)->l2bsize;
3564 			goto getParent;
3565 		}
3566 		tlck = txLock(tid, ip, mp, tlckXTREE);
3567 		tlck->type = tlckXTREE | tlckTRUNCATE;
3568 		xtlck = (struct xtlock *) & tlck->lock;
3569 		xtlck->hwm.offset = le16_to_cpu(p->header.nextindex) - 1;
3570 	}
3571 	BT_MARK_DIRTY(mp, ip);
3572 
3573 	/*
3574 	 * scan backward leaf page entries
3575 	 */
3576 	for (; index >= XTENTRYSTART; index--) {
3577 		xad = &p->xad[index];
3578 		xoff = offsetXAD(xad);
3579 		xlen = lengthXAD(xad);
3580 		xaddr = addressXAD(xad);
3581 
3582 		/*
3583 		 * The "data" for a directory is indexed by the block
3584 		 * device's address space.  This metadata must be invalidated
3585 		 * here
3586 		 */
3587 		if (S_ISDIR(ip->i_mode) && (teof == 0))
3588 			invalidate_xad_metapages(ip, *xad);
3589 		/*
3590 		 * entry beyond eof: continue scan of current page
3591 		 *          xad
3592 		 * ---|---=======------->
3593 		 *   eof
3594 		 */
3595 		if (teof < xoff) {
3596 			nfreed += xlen;
3597 			continue;
3598 		}
3599 
3600 		/*
3601 		 * (xoff <= teof): last entry to be deleted from page;
3602 		 * If other entries remain in page: keep and update the page.
3603 		 */
3604 
3605 		/*
3606 		 * eof == entry_start: delete the entry
3607 		 *           xad
3608 		 * -------|=======------->
3609 		 *       eof
3610 		 *
3611 		 */
3612 		if (teof == xoff) {
3613 			nfreed += xlen;
3614 
3615 			if (index == XTENTRYSTART)
3616 				break;
3617 
3618 			nextindex = index;
3619 		}
3620 		/*
3621 		 * eof within the entry: truncate the entry.
3622 		 *          xad
3623 		 * -------===|===------->
3624 		 *          eof
3625 		 */
3626 		else if (teof < xoff + xlen) {
3627 			/* update truncated entry */
3628 			len = teof - xoff;
3629 			freexlen = xlen - len;
3630 			XADlength(xad, len);
3631 
3632 			/* save pxd of truncated extent in tlck */
3633 			xaddr += len;
3634 			if (log) {	/* COMMIT_PWMAP */
3635 				xtlck->lwm.offset = (xtlck->lwm.offset) ?
3636 				    min(index, (int)xtlck->lwm.offset) : index;
3637 				xtlck->lwm.length = index + 1 -
3638 				    xtlck->lwm.offset;
3639 				xtlck->twm.offset = index;
3640 				pxdlock = (struct pxd_lock *) & xtlck->pxdlock;
3641 				pxdlock->flag = mlckFREEPXD;
3642 				PXDaddress(&pxdlock->pxd, xaddr);
3643 				PXDlength(&pxdlock->pxd, freexlen);
3644 			}
3645 			/* free truncated extent */
3646 			else {	/* COMMIT_WMAP */
3647 
3648 				pxdlock = (struct pxd_lock *) & xadlock;
3649 				pxdlock->flag = mlckFREEPXD;
3650 				PXDaddress(&pxdlock->pxd, xaddr);
3651 				PXDlength(&pxdlock->pxd, freexlen);
3652 				txFreeMap(ip, pxdlock, NULL, COMMIT_WMAP);
3653 
3654 				/* reset map lock */
3655 				xadlock.flag = mlckFREEXADLIST;
3656 			}
3657 
3658 			/* current entry is new last entry; */
3659 			nextindex = index + 1;
3660 
3661 			nfreed += freexlen;
3662 		}
3663 		/*
3664 		 * eof beyond the entry:
3665 		 *          xad
3666 		 * -------=======---|--->
3667 		 *                 eof
3668 		 */
3669 		else {		/* (xoff + xlen < teof) */
3670 
3671 			nextindex = index + 1;
3672 		}
3673 
3674 		if (nextindex < le16_to_cpu(p->header.nextindex)) {
3675 			if (!log) {	/* COMMIT_WAMP */
3676 				xadlock.xdlist = &p->xad[nextindex];
3677 				xadlock.count =
3678 				    le16_to_cpu(p->header.nextindex) -
3679 				    nextindex;
3680 				txFreeMap(ip, (struct maplock *) & xadlock,
3681 					  NULL, COMMIT_WMAP);
3682 			}
3683 			p->header.nextindex = cpu_to_le16(nextindex);
3684 		}
3685 
3686 		XT_PUTPAGE(mp);
3687 
3688 		/* assert(freed == 0); */
3689 		goto getParent;
3690 	}			/* end scan of leaf page entries */
3691 
3692 	freed = 1;
3693 
3694 	/*
3695 	 * leaf page become empty: free the page if type != PMAP
3696 	 */
3697 	if (log) {		/* COMMIT_PWMAP */
3698 		/* txCommit() with tlckFREE:
3699 		 * free data extents covered by leaf [XTENTRYSTART:hwm);
3700 		 * invalidate leaf if COMMIT_PWMAP;
3701 		 * if (TRUNCATE), will write LOG_NOREDOPAGE;
3702 		 */
3703 		tlck->type = tlckXTREE | tlckFREE;
3704 	} else {		/* COMMIT_WAMP */
3705 
3706 		/* free data extents covered by leaf */
3707 		xadlock.xdlist = &p->xad[XTENTRYSTART];
3708 		xadlock.count =
3709 		    le16_to_cpu(p->header.nextindex) - XTENTRYSTART;
3710 		txFreeMap(ip, (struct maplock *) & xadlock, NULL, COMMIT_WMAP);
3711 	}
3712 
3713 	if (p->header.flag & BT_ROOT) {
3714 		p->header.flag &= ~BT_INTERNAL;
3715 		p->header.flag |= BT_LEAF;
3716 		p->header.nextindex = cpu_to_le16(XTENTRYSTART);
3717 
3718 		XT_PUTPAGE(mp);	/* debug */
3719 		goto out;
3720 	} else {
3721 		if (log) {	/* COMMIT_PWMAP */
3722 			/* page will be invalidated at tx completion
3723 			 */
3724 			XT_PUTPAGE(mp);
3725 		} else {	/* COMMIT_WMAP */
3726 
3727 			if (mp->lid)
3728 				lid_to_tlock(mp->lid)->flag |= tlckFREELOCK;
3729 
3730 			/* invalidate empty leaf page */
3731 			discard_metapage(mp);
3732 		}
3733 	}
3734 
3735 	/*
3736 	 * the leaf page become empty: delete the parent entry
3737 	 * for the leaf page if the parent page is to be kept
3738 	 * in the new sized file.
3739 	 */
3740 
3741 	/*
3742 	 * go back up to the parent page
3743 	 */
3744       getParent:
3745 	/* pop/restore parent entry for the current child page */
3746 	if ((parent = BT_POP(&btstack)) == NULL)
3747 		/* current page must have been root */
3748 		goto out;
3749 
3750 	/* get back the parent page */
3751 	bn = parent->bn;
3752 	XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
3753 	if (rc)
3754 		return rc;
3755 
3756 	index = parent->index;
3757 
3758 	/*
3759 	 * child page was not empty:
3760 	 */
3761 	if (freed == 0) {
3762 		/* has any entry deleted from parent ? */
3763 		if (index < le16_to_cpu(p->header.nextindex) - 1) {
3764 			/* (re)acquire tlock on the parent page */
3765 			if (log) {	/* COMMIT_PWMAP */
3766 				/* txCommit() with tlckTRUNCATE:
3767 				 * free child extents covered by parent [);
3768 				 */
3769 				tlck = txLock(tid, ip, mp, tlckXTREE);
3770 				xtlck = (struct xtlock *) & tlck->lock;
3771 				if (!(tlck->type & tlckTRUNCATE)) {
3772 					xtlck->hwm.offset =
3773 					    le16_to_cpu(p->header.
3774 							nextindex) - 1;
3775 					tlck->type =
3776 					    tlckXTREE | tlckTRUNCATE;
3777 				}
3778 			} else {	/* COMMIT_WMAP */
3779 
3780 				/* free child extents covered by parent */
3781 				xadlock.xdlist = &p->xad[index + 1];
3782 				xadlock.count =
3783 				    le16_to_cpu(p->header.nextindex) -
3784 				    index - 1;
3785 				txFreeMap(ip, (struct maplock *) & xadlock,
3786 					  NULL, COMMIT_WMAP);
3787 			}
3788 			BT_MARK_DIRTY(mp, ip);
3789 
3790 			p->header.nextindex = cpu_to_le16(index + 1);
3791 		}
3792 		XT_PUTPAGE(mp);
3793 		goto getParent;
3794 	}
3795 
3796 	/*
3797 	 * child page was empty:
3798 	 */
3799 	nfreed += lengthXAD(&p->xad[index]);
3800 
3801 	/*
3802 	 * During working map update, child page's tlock must be handled
3803 	 * before parent's.  This is because the parent's tlock will cause
3804 	 * the child's disk space to be marked available in the wmap, so
3805 	 * it's important that the child page be released by that time.
3806 	 *
3807 	 * ToDo:  tlocks should be on doubly-linked list, so we can
3808 	 * quickly remove it and add it to the end.
3809 	 */
3810 
3811 	/*
3812 	 * Move parent page's tlock to the end of the tid's tlock list
3813 	 */
3814 	if (log && mp->lid && (tblk->last != mp->lid) &&
3815 	    lid_to_tlock(mp->lid)->tid) {
3816 		lid_t lid = mp->lid;
3817 		struct tlock *prev;
3818 
3819 		tlck = lid_to_tlock(lid);
3820 
3821 		if (tblk->next == lid)
3822 			tblk->next = tlck->next;
3823 		else {
3824 			for (prev = lid_to_tlock(tblk->next);
3825 			     prev->next != lid;
3826 			     prev = lid_to_tlock(prev->next)) {
3827 				assert(prev->next);
3828 			}
3829 			prev->next = tlck->next;
3830 		}
3831 		lid_to_tlock(tblk->last)->next = lid;
3832 		tlck->next = 0;
3833 		tblk->last = lid;
3834 	}
3835 
3836 	/*
3837 	 * parent page become empty: free the page
3838 	 */
3839 	if (index == XTENTRYSTART) {
3840 		if (log) {	/* COMMIT_PWMAP */
3841 			/* txCommit() with tlckFREE:
3842 			 * free child extents covered by parent;
3843 			 * invalidate parent if COMMIT_PWMAP;
3844 			 */
3845 			tlck = txLock(tid, ip, mp, tlckXTREE);
3846 			xtlck = (struct xtlock *) & tlck->lock;
3847 			xtlck->hwm.offset =
3848 			    le16_to_cpu(p->header.nextindex) - 1;
3849 			tlck->type = tlckXTREE | tlckFREE;
3850 		} else {	/* COMMIT_WMAP */
3851 
3852 			/* free child extents covered by parent */
3853 			xadlock.xdlist = &p->xad[XTENTRYSTART];
3854 			xadlock.count =
3855 			    le16_to_cpu(p->header.nextindex) -
3856 			    XTENTRYSTART;
3857 			txFreeMap(ip, (struct maplock *) & xadlock, NULL,
3858 				  COMMIT_WMAP);
3859 		}
3860 		BT_MARK_DIRTY(mp, ip);
3861 
3862 		if (p->header.flag & BT_ROOT) {
3863 			p->header.flag &= ~BT_INTERNAL;
3864 			p->header.flag |= BT_LEAF;
3865 			p->header.nextindex = cpu_to_le16(XTENTRYSTART);
3866 			if (le16_to_cpu(p->header.maxentry) == XTROOTMAXSLOT) {
3867 				/*
3868 				 * Shrink root down to allow inline
3869 				 * EA (otherwise fsck complains)
3870 				 */
3871 				p->header.maxentry =
3872 				    cpu_to_le16(XTROOTINITSLOT);
3873 				JFS_IP(ip)->mode2 |= INLINEEA;
3874 			}
3875 
3876 			XT_PUTPAGE(mp);	/* debug */
3877 			goto out;
3878 		} else {
3879 			if (log) {	/* COMMIT_PWMAP */
3880 				/* page will be invalidated at tx completion
3881 				 */
3882 				XT_PUTPAGE(mp);
3883 			} else {	/* COMMIT_WMAP */
3884 
3885 				if (mp->lid)
3886 					lid_to_tlock(mp->lid)->flag |=
3887 						tlckFREELOCK;
3888 
3889 				/* invalidate parent page */
3890 				discard_metapage(mp);
3891 			}
3892 
3893 			/* parent has become empty and freed:
3894 			 * go back up to its parent page
3895 			 */
3896 			/* freed = 1; */
3897 			goto getParent;
3898 		}
3899 	}
3900 	/*
3901 	 * parent page still has entries for front region;
3902 	 */
3903 	else {
3904 		/* try truncate region covered by preceding entry
3905 		 * (process backward)
3906 		 */
3907 		index--;
3908 
3909 		/* go back down to the child page corresponding
3910 		 * to the entry
3911 		 */
3912 		goto getChild;
3913 	}
3914 
3915 	/*
3916 	 *	internal page: go down to child page of current entry
3917 	 */
3918       getChild:
3919 	/* save current parent entry for the child page */
3920 	if (BT_STACK_FULL(&btstack)) {
3921 		jfs_error(ip->i_sb, "stack overrun in xtTruncate!");
3922 		XT_PUTPAGE(mp);
3923 		return -EIO;
3924 	}
3925 	BT_PUSH(&btstack, bn, index);
3926 
3927 	/* get child page */
3928 	xad = &p->xad[index];
3929 	bn = addressXAD(xad);
3930 
3931 	/*
3932 	 * first access of each internal entry:
3933 	 */
3934 	/* release parent page */
3935 	XT_PUTPAGE(mp);
3936 
3937 	/* process the child page */
3938 	goto getPage;
3939 
3940       out:
3941 	/*
3942 	 * update file resource stat
3943 	 */
3944 	/* set size
3945 	 */
3946 	if (S_ISDIR(ip->i_mode) && !newsize)
3947 		ip->i_size = 1;	/* fsck hates zero-length directories */
3948 	else
3949 		ip->i_size = newsize;
3950 
3951 	/* update quota allocation to reflect freed blocks */
3952 	DQUOT_FREE_BLOCK(ip, nfreed);
3953 
3954 	/*
3955 	 * free tlock of invalidated pages
3956 	 */
3957 	if (flag == COMMIT_WMAP)
3958 		txFreelock(ip);
3959 
3960 	return newsize;
3961 }
3962 
3963 
3964 /*
3965  *	xtTruncate_pmap()
3966  *
3967  * function:
3968  *	Perform truncate to zero lenghth for deleted file, leaving the
3969  *	the xtree and working map untouched.  This allows the file to
3970  *	be accessed via open file handles, while the delete of the file
3971  *	is committed to disk.
3972  *
3973  * parameter:
3974  *	tid_t		tid,
3975  *	struct inode	*ip,
3976  *	s64		committed_size)
3977  *
3978  * return: new committed size
3979  *
3980  * note:
3981  *
3982  *	To avoid deadlock by holding too many transaction locks, the
3983  *	truncation may be broken up into multiple transactions.
3984  *	The committed_size keeps track of part of the file has been
3985  *	freed from the pmaps.
3986  */
3987 s64 xtTruncate_pmap(tid_t tid, struct inode *ip, s64 committed_size)
3988 {
3989 	s64 bn;
3990 	struct btstack btstack;
3991 	int cmp;
3992 	int index;
3993 	int locked_leaves = 0;
3994 	struct metapage *mp;
3995 	xtpage_t *p;
3996 	struct btframe *parent;
3997 	int rc;
3998 	struct tblock *tblk;
3999 	struct tlock *tlck = NULL;
4000 	xad_t *xad;
4001 	int xlen;
4002 	s64 xoff;
4003 	struct xtlock *xtlck = NULL;
4004 
4005 	/* save object truncation type */
4006 	tblk = tid_to_tblock(tid);
4007 	tblk->xflag |= COMMIT_PMAP;
4008 
4009 	/* clear stack */
4010 	BT_CLR(&btstack);
4011 
4012 	if (committed_size) {
4013 		xoff = (committed_size >> JFS_SBI(ip->i_sb)->l2bsize) - 1;
4014 		rc = xtSearch(ip, xoff, NULL, &cmp, &btstack, 0);
4015 		if (rc)
4016 			return rc;
4017 
4018 		XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
4019 
4020 		if (cmp != 0) {
4021 			XT_PUTPAGE(mp);
4022 			jfs_error(ip->i_sb,
4023 				  "xtTruncate_pmap: did not find extent");
4024 			return -EIO;
4025 		}
4026 	} else {
4027 		/*
4028 		 * start with root
4029 		 *
4030 		 * root resides in the inode
4031 		 */
4032 		bn = 0;
4033 
4034 		/*
4035 		 * first access of each page:
4036 		 */
4037       getPage:
4038 		XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
4039 		if (rc)
4040 			return rc;
4041 
4042 		/* process entries backward from last index */
4043 		index = le16_to_cpu(p->header.nextindex) - 1;
4044 
4045 		if (p->header.flag & BT_INTERNAL)
4046 			goto getChild;
4047 	}
4048 
4049 	/*
4050 	 *	leaf page
4051 	 */
4052 
4053 	if (++locked_leaves > MAX_TRUNCATE_LEAVES) {
4054 		/*
4055 		 * We need to limit the size of the transaction
4056 		 * to avoid exhausting pagecache & tlocks
4057 		 */
4058 		xad = &p->xad[index];
4059 		xoff = offsetXAD(xad);
4060 		xlen = lengthXAD(xad);
4061 		XT_PUTPAGE(mp);
4062 		return (xoff + xlen) << JFS_SBI(ip->i_sb)->l2bsize;
4063 	}
4064 	tlck = txLock(tid, ip, mp, tlckXTREE);
4065 	tlck->type = tlckXTREE | tlckFREE;
4066 	xtlck = (struct xtlock *) & tlck->lock;
4067 	xtlck->hwm.offset = index;
4068 
4069 
4070 	XT_PUTPAGE(mp);
4071 
4072 	/*
4073 	 * go back up to the parent page
4074 	 */
4075       getParent:
4076 	/* pop/restore parent entry for the current child page */
4077 	if ((parent = BT_POP(&btstack)) == NULL)
4078 		/* current page must have been root */
4079 		goto out;
4080 
4081 	/* get back the parent page */
4082 	bn = parent->bn;
4083 	XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
4084 	if (rc)
4085 		return rc;
4086 
4087 	index = parent->index;
4088 
4089 	/*
4090 	 * parent page become empty: free the page
4091 	 */
4092 	if (index == XTENTRYSTART) {
4093 		/* txCommit() with tlckFREE:
4094 		 * free child extents covered by parent;
4095 		 * invalidate parent if COMMIT_PWMAP;
4096 		 */
4097 		tlck = txLock(tid, ip, mp, tlckXTREE);
4098 		xtlck = (struct xtlock *) & tlck->lock;
4099 		xtlck->hwm.offset = le16_to_cpu(p->header.nextindex) - 1;
4100 		tlck->type = tlckXTREE | tlckFREE;
4101 
4102 		XT_PUTPAGE(mp);
4103 
4104 		if (p->header.flag & BT_ROOT) {
4105 
4106 			goto out;
4107 		} else {
4108 			goto getParent;
4109 		}
4110 	}
4111 	/*
4112 	 * parent page still has entries for front region;
4113 	 */
4114 	else
4115 		index--;
4116 	/*
4117 	 *	internal page: go down to child page of current entry
4118 	 */
4119       getChild:
4120 	/* save current parent entry for the child page */
4121 	if (BT_STACK_FULL(&btstack)) {
4122 		jfs_error(ip->i_sb, "stack overrun in xtTruncate_pmap!");
4123 		XT_PUTPAGE(mp);
4124 		return -EIO;
4125 	}
4126 	BT_PUSH(&btstack, bn, index);
4127 
4128 	/* get child page */
4129 	xad = &p->xad[index];
4130 	bn = addressXAD(xad);
4131 
4132 	/*
4133 	 * first access of each internal entry:
4134 	 */
4135 	/* release parent page */
4136 	XT_PUTPAGE(mp);
4137 
4138 	/* process the child page */
4139 	goto getPage;
4140 
4141       out:
4142 
4143 	return 0;
4144 }
4145 
4146 #ifdef CONFIG_JFS_STATISTICS
4147 int jfs_xtstat_read(char *buffer, char **start, off_t offset, int length,
4148 		    int *eof, void *data)
4149 {
4150 	int len = 0;
4151 	off_t begin;
4152 
4153 	len += sprintf(buffer,
4154 		       "JFS Xtree statistics\n"
4155 		       "====================\n"
4156 		       "searches = %d\n"
4157 		       "fast searches = %d\n"
4158 		       "splits = %d\n",
4159 		       xtStat.search,
4160 		       xtStat.fastSearch,
4161 		       xtStat.split);
4162 
4163 	begin = offset;
4164 	*start = buffer + begin;
4165 	len -= begin;
4166 
4167 	if (len > length)
4168 		len = length;
4169 	else
4170 		*eof = 1;
4171 
4172 	if (len < 0)
4173 		len = 0;
4174 
4175 	return len;
4176 }
4177 #endif
4178