1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4	* All Rights Reserved.
5	*/
6	#include "xfs.h"
7	#include "xfs_fs.h"
8	#include "xfs_shared.h"
9	#include "xfs_format.h"
10	#include "xfs_log_format.h"
11	#include "xfs_trans_resv.h"
12	#include "xfs_bit.h"
13	#include "xfs_mount.h"
14	#include "xfs_inode.h"
15	#include "xfs_trans.h"
16	#include "xfs_buf_item.h"
17	#include "xfs_btree.h"
18	#include "xfs_errortag.h"
19	#include "xfs_error.h"
20	#include "xfs_trace.h"
21	#include "xfs_alloc.h"
22	#include "xfs_log.h"
23	#include "xfs_btree_staging.h"
24	#include "xfs_ag.h"
25	#include "xfs_alloc_btree.h"
26	#include "xfs_ialloc_btree.h"
27	#include "xfs_bmap_btree.h"
28	#include "xfs_rmap_btree.h"
29	#include "xfs_refcount_btree.h"
30	#include "xfs_health.h"
31	#include "xfs_buf_mem.h"
32	#include "xfs_btree_mem.h"
33
34	/*
35	* Btree magic numbers.
36	*/
37	uint32_t
38	xfs_btree_magic(
39	struct xfs_mount *mp,
40	const struct xfs_btree_ops *ops)
41	{
42	int idx = xfs_has_crc(mp) ? 1 : 0;
43	__be32 magic = ops->buf_ops->magic[idx];
44
45	/* Ensure we asked for crc for crc-only magics. */
46	ASSERT(magic != 0);
47	return be32_to_cpu(magic);
48	}
49
50	/*
51	* These sibling pointer checks are optimised for null sibling pointers. This
52	* happens a lot, and we don't need to byte swap at runtime if the sibling
53	* pointer is NULL.
54	*
55	* These are explicitly marked at inline because the cost of calling them as
56	* functions instead of inlining them is about 36 bytes extra code per call site
57	* on x86-64. Yes, gcc-11 fails to inline them, and explicit inlining of these
58	* two sibling check functions reduces the compiled code size by over 300
59	* bytes.
60	*/
61	static inline xfs_failaddr_t
62	xfs_btree_check_fsblock_siblings(
63	struct xfs_mount *mp,
64	xfs_fsblock_t fsb,
65	__be64 dsibling)
66	{
67	xfs_fsblock_t sibling;
68
69	if (dsibling == cpu_to_be64(NULLFSBLOCK))
70	return NULL;
71
72	sibling = be64_to_cpu(dsibling);
73	if (sibling == fsb)
74	return __this_address;
75	if (!xfs_verify_fsbno(mp, sibling))
76	return __this_address;
77	return NULL;
78	}
79
80	static inline xfs_failaddr_t
81	xfs_btree_check_memblock_siblings(
82	struct xfs_buftarg *btp,
83	xfbno_t bno,
84	__be64 dsibling)
85	{
86	xfbno_t sibling;
87
88	if (dsibling == cpu_to_be64(NULLFSBLOCK))
89	return NULL;
90
91	sibling = be64_to_cpu(dsibling);
92	if (sibling == bno)
93	return __this_address;
94	if (!xmbuf_verify_daddr(btp, xfbno_to_daddr(sibling)))
95	return __this_address;
96	return NULL;
97	}
98
99	static inline xfs_failaddr_t
100	xfs_btree_check_agblock_siblings(
101	struct xfs_perag *pag,
102	xfs_agblock_t agbno,
103	__be32 dsibling)
104	{
105	xfs_agblock_t sibling;
106
107	if (dsibling == cpu_to_be32(NULLAGBLOCK))
108	return NULL;
109
110	sibling = be32_to_cpu(dsibling);
111	if (sibling == agbno)
112	return __this_address;
113	if (!xfs_verify_agbno(pag, sibling))
114	return __this_address;
115	return NULL;
116	}
117
118	static xfs_failaddr_t
119	__xfs_btree_check_lblock_hdr(
120	struct xfs_btree_cur *cur,
121	struct xfs_btree_block *block,
122	int level,
123	struct xfs_buf *bp)
124	{
125	struct xfs_mount *mp = cur->bc_mp;
126
127	if (xfs_has_crc(mp)) {
128	if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
129	return __this_address;
130	if (block->bb_u.l.bb_blkno !=
131	cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
132	return __this_address;
133	if (block->bb_u.l.bb_pad != cpu_to_be32(0))
134	return __this_address;
135	}
136
137	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(mp, cur->bc_ops))
138	return __this_address;
139	if (be16_to_cpu(block->bb_level) != level)
140	return __this_address;
141	if (be16_to_cpu(block->bb_numrecs) >
142	cur->bc_ops->get_maxrecs(cur, level))
143	return __this_address;
144
145	return NULL;
146	}
147
148	/*
149	* Check a long btree block header. Return the address of the failing check,
150	* or NULL if everything is ok.
151	*/
152	static xfs_failaddr_t
153	__xfs_btree_check_fsblock(
154	struct xfs_btree_cur *cur,
155	struct xfs_btree_block *block,
156	int level,
157	struct xfs_buf *bp)
158	{
159	struct xfs_mount *mp = cur->bc_mp;
160	xfs_failaddr_t fa;
161	xfs_fsblock_t fsb;
162
163	fa = __xfs_btree_check_lblock_hdr(cur, block, level, bp);
164	if (fa)
165	return fa;
166
167	/*
168	* For inode-rooted btrees, the root block sits in the inode fork. In
169	* that case bp is NULL, and the block must not have any siblings.
170	*/
171	if (!bp) {
172	if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK))
173	return __this_address;
174	if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK))
175	return __this_address;
176	return NULL;
177	}
178
179	fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
180	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
181	block->bb_u.l.bb_leftsib);
182	if (!fa)
183	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
184	block->bb_u.l.bb_rightsib);
185	return fa;
186	}
187
188	/*
189	* Check an in-memory btree block header. Return the address of the failing
190	* check, or NULL if everything is ok.
191	*/
192	static xfs_failaddr_t
193	__xfs_btree_check_memblock(
194	struct xfs_btree_cur *cur,
195	struct xfs_btree_block *block,
196	int level,
197	struct xfs_buf *bp)
198	{
199	struct xfs_buftarg *btp = cur->bc_mem.xfbtree->target;
200	xfs_failaddr_t fa;
201	xfbno_t bno;
202
203	fa = __xfs_btree_check_lblock_hdr(cur, block, level, bp);
204	if (fa)
205	return fa;
206
207	bno = xfs_daddr_to_xfbno(xfs_buf_daddr(bp));
208	fa = xfs_btree_check_memblock_siblings(btp, bno,
209	block->bb_u.l.bb_leftsib);
210	if (!fa)
211	fa = xfs_btree_check_memblock_siblings(btp, bno,
212	block->bb_u.l.bb_rightsib);
213	return fa;
214	}
215
216	/*
217	* Check a short btree block header. Return the address of the failing check,
218	* or NULL if everything is ok.
219	*/
220	static xfs_failaddr_t
221	__xfs_btree_check_agblock(
222	struct xfs_btree_cur *cur,
223	struct xfs_btree_block *block,
224	int level,
225	struct xfs_buf *bp)
226	{
227	struct xfs_mount *mp = cur->bc_mp;
228	struct xfs_perag *pag = cur->bc_ag.pag;
229	xfs_failaddr_t fa;
230	xfs_agblock_t agbno;
231
232	if (xfs_has_crc(mp)) {
233	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
234	return __this_address;
235	if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
236	return __this_address;
237	}
238
239	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(mp, cur->bc_ops))
240	return __this_address;
241	if (be16_to_cpu(block->bb_level) != level)
242	return __this_address;
243	if (be16_to_cpu(block->bb_numrecs) >
244	cur->bc_ops->get_maxrecs(cur, level))
245	return __this_address;
246
247	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
248	fa = xfs_btree_check_agblock_siblings(pag, agbno,
249	block->bb_u.s.bb_leftsib);
250	if (!fa)
251	fa = xfs_btree_check_agblock_siblings(pag, agbno,
252	block->bb_u.s.bb_rightsib);
253	return fa;
254	}
255
256	/*
257	* Internal btree block check.
258	*
259	* Return NULL if the block is ok or the address of the failed check otherwise.
260	*/
261	xfs_failaddr_t
262	__xfs_btree_check_block(
263	struct xfs_btree_cur *cur,
264	struct xfs_btree_block *block,
265	int level,
266	struct xfs_buf *bp)
267	{
268	switch (cur->bc_ops->type) {
269	case XFS_BTREE_TYPE_MEM:
270	return __xfs_btree_check_memblock(cur, block, level, bp);
271	case XFS_BTREE_TYPE_AG:
272	return __xfs_btree_check_agblock(cur, block, level, bp);
273	case XFS_BTREE_TYPE_INODE:
274	return __xfs_btree_check_fsblock(cur, block, level, bp);
275	default:
276	ASSERT(0);
277	return __this_address;
278	}
279	}
280
281	static inline unsigned int xfs_btree_block_errtag(struct xfs_btree_cur *cur)
282	{
283	if (cur->bc_ops->ptr_len == XFS_BTREE_SHORT_PTR_LEN)
284	return XFS_ERRTAG_BTREE_CHECK_SBLOCK;
285	return XFS_ERRTAG_BTREE_CHECK_LBLOCK;
286	}
287
288	/*
289	* Debug routine: check that block header is ok.
290	*/
291	int
292	xfs_btree_check_block(
293	struct xfs_btree_cur *cur, /* btree cursor */
294	struct xfs_btree_block *block, /* generic btree block pointer */
295	int level, /* level of the btree block */
296	struct xfs_buf *bp) /* buffer containing block, if any */
297	{
298	struct xfs_mount *mp = cur->bc_mp;
299	xfs_failaddr_t fa;
300
301	fa = __xfs_btree_check_block(cur, block, level, bp);
302	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
303	XFS_TEST_ERROR(false, mp, xfs_btree_block_errtag(cur))) {
304	if (bp)
305	trace_xfs_btree_corrupt(bp, _RET_IP_);
306	xfs_btree_mark_sick(cur);
307	return -EFSCORRUPTED;
308	}
309	return 0;
310	}
311
312	int
313	__xfs_btree_check_ptr(
314	struct xfs_btree_cur *cur,
315	const union xfs_btree_ptr *ptr,
316	int index,
317	int level)
318	{
319	if (level <= 0)
320	return -EFSCORRUPTED;
321
322	switch (cur->bc_ops->type) {
323	case XFS_BTREE_TYPE_MEM:
324	if (!xfbtree_verify_bno(cur->bc_mem.xfbtree,
325	be64_to_cpu((&ptr->l)[index])))
326	return -EFSCORRUPTED;
327	break;
328	case XFS_BTREE_TYPE_INODE:
329	if (!xfs_verify_fsbno(cur->bc_mp,
330	be64_to_cpu((&ptr->l)[index])))
331	return -EFSCORRUPTED;
332	break;
333	case XFS_BTREE_TYPE_AG:
334	if (!xfs_verify_agbno(cur->bc_ag.pag,
335	be32_to_cpu((&ptr->s)[index])))
336	return -EFSCORRUPTED;
337	break;
338	}
339
340	return 0;
341	}
342
343	/*
344	* Check that a given (indexed) btree pointer at a certain level of a
345	* btree is valid and doesn't point past where it should.
346	*/
347	static int
348	xfs_btree_check_ptr(
349	struct xfs_btree_cur *cur,
350	const union xfs_btree_ptr *ptr,
351	int index,
352	int level)
353	{
354	int error;
355
356	error = __xfs_btree_check_ptr(cur, ptr, index, level);
357	if (error) {
358	switch (cur->bc_ops->type) {
359	case XFS_BTREE_TYPE_MEM:
360	xfs_err(cur->bc_mp,
361	"In-memory: Corrupt %sbt flags 0x%x pointer at level %d index %d fa %pS.",
362	cur->bc_ops->name, cur->bc_flags, level, index,
363	__this_address);
364	break;
365	case XFS_BTREE_TYPE_INODE:
366	xfs_err(cur->bc_mp,
367	"Inode %llu fork %d: Corrupt %sbt pointer at level %d index %d.",
368	cur->bc_ino.ip->i_ino,
369	cur->bc_ino.whichfork, cur->bc_ops->name,
370	level, index);
371	break;
372	case XFS_BTREE_TYPE_AG:
373	xfs_err(cur->bc_mp,
374	"AG %u: Corrupt %sbt pointer at level %d index %d.",
375	cur->bc_ag.pag->pag_agno, cur->bc_ops->name,
376	level, index);
377	break;
378	}
379	xfs_btree_mark_sick(cur);
380	}
381
382	return error;
383	}
384
385	#ifdef DEBUG
386	# define xfs_btree_debug_check_ptr xfs_btree_check_ptr
387	#else
388	# define xfs_btree_debug_check_ptr(...) (0)
389	#endif
390
391	/*
392	* Calculate CRC on the whole btree block and stuff it into the
393	* long-form btree header.
394	*
395	* Prior to calculting the CRC, pull the LSN out of the buffer log item and put
396	* it into the buffer so recovery knows what the last modification was that made
397	* it to disk.
398	*/
399	void
400	xfs_btree_fsblock_calc_crc(
401	struct xfs_buf *bp)
402	{
403	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
404	struct xfs_buf_log_item *bip = bp->b_log_item;
405
406	if (!xfs_has_crc(bp->b_mount))
407	return;
408	if (bip)
409	block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
410	xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
411	}
412
413	bool
414	xfs_btree_fsblock_verify_crc(
415	struct xfs_buf *bp)
416	{
417	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
418	struct xfs_mount *mp = bp->b_mount;
419
420	if (xfs_has_crc(mp)) {
421	if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
422	return false;
423	return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
424	}
425
426	return true;
427	}
428
429	/*
430	* Calculate CRC on the whole btree block and stuff it into the
431	* short-form btree header.
432	*
433	* Prior to calculting the CRC, pull the LSN out of the buffer log item and put
434	* it into the buffer so recovery knows what the last modification was that made
435	* it to disk.
436	*/
437	void
438	xfs_btree_agblock_calc_crc(
439	struct xfs_buf *bp)
440	{
441	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
442	struct xfs_buf_log_item *bip = bp->b_log_item;
443
444	if (!xfs_has_crc(bp->b_mount))
445	return;
446	if (bip)
447	block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
448	xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
449	}
450
451	bool
452	xfs_btree_agblock_verify_crc(
453	struct xfs_buf *bp)
454	{
455	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
456	struct xfs_mount *mp = bp->b_mount;
457
458	if (xfs_has_crc(mp)) {
459	if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
460	return false;
461	return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
462	}
463
464	return true;
465	}
466
467	static int
468	xfs_btree_free_block(
469	struct xfs_btree_cur *cur,
470	struct xfs_buf *bp)
471	{
472	int error;
473
474	trace_xfs_btree_free_block(cur, bp);
475
476	/*
477	* Don't allow block freeing for a staging cursor, because staging
478	* cursors do not support regular btree modifications.
479	*/
480	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
481	ASSERT(0);
482	return -EFSCORRUPTED;
483	}
484
485	error = cur->bc_ops->free_block(cur, bp);
486	if (!error) {
487	xfs_trans_binval(cur->bc_tp, bp);
488	XFS_BTREE_STATS_INC(cur, free);
489	}
490	return error;
491	}
492
493	/*
494	* Delete the btree cursor.
495	*/
496	void
497	xfs_btree_del_cursor(
498	struct xfs_btree_cur *cur, /* btree cursor */
499	int error) /* del because of error */
500	{
501	int i; /* btree level */
502
503	/*
504	* Clear the buffer pointers and release the buffers. If we're doing
505	* this because of an error, inspect all of the entries in the bc_bufs
506	* array for buffers to be unlocked. This is because some of the btree
507	* code works from level n down to 0, and if we get an error along the
508	* way we won't have initialized all the entries down to 0.
509	*/
510	for (i = 0; i < cur->bc_nlevels; i++) {
511	if (cur->bc_levels[i].bp)
512	xfs_trans_brelse(cur->bc_tp, cur->bc_levels[i].bp);
513	else if (!error)
514	break;
515	}
516
517	/*
518	* If we are doing a BMBT update, the number of unaccounted blocks
519	* allocated during this cursor life time should be zero. If it's not
520	* zero, then we should be shut down or on our way to shutdown due to
521	* cancelling a dirty transaction on error.
522	*/
523	ASSERT(!xfs_btree_is_bmap(cur->bc_ops) || cur->bc_bmap.allocated == 0 ||
524	xfs_is_shutdown(cur->bc_mp) || error != 0);
525
526	switch (cur->bc_ops->type) {
527	case XFS_BTREE_TYPE_AG:
528	if (cur->bc_ag.pag)
529	xfs_perag_put(pag: cur->bc_ag.pag);
530	break;
531	case XFS_BTREE_TYPE_INODE:
532	/* nothing to do */
533	break;
534	case XFS_BTREE_TYPE_MEM:
535	if (cur->bc_mem.pag)
536	xfs_perag_put(pag: cur->bc_mem.pag);
537	break;
538	}
539
540	kmem_cache_free(cur->bc_cache, cur);
541	}
542
543	/* Return the buffer target for this btree's buffer. */
544	static inline struct xfs_buftarg *
545	xfs_btree_buftarg(
546	struct xfs_btree_cur *cur)
547	{
548	if (cur->bc_ops->type == XFS_BTREE_TYPE_MEM)
549	return cur->bc_mem.xfbtree->target;
550	return cur->bc_mp->m_ddev_targp;
551	}
552
553	/* Return the block size (in units of 512b sectors) for this btree. */
554	static inline unsigned int
555	xfs_btree_bbsize(
556	struct xfs_btree_cur *cur)
557	{
558	if (cur->bc_ops->type == XFS_BTREE_TYPE_MEM)
559	return XFBNO_BBSIZE;
560	return cur->bc_mp->m_bsize;
561	}
562
563	/*
564	* Duplicate the btree cursor.
565	* Allocate a new one, copy the record, re-get the buffers.
566	*/
567	int /* error */
568	xfs_btree_dup_cursor(
569	struct xfs_btree_cur *cur, /* input cursor */
570	struct xfs_btree_cur **ncur) /* output cursor */
571	{
572	struct xfs_mount *mp = cur->bc_mp;
573	struct xfs_trans *tp = cur->bc_tp;
574	struct xfs_buf *bp;
575	struct xfs_btree_cur *new;
576	int error;
577	int i;
578
579	/*
580	* Don't allow staging cursors to be duplicated because they're supposed
581	* to be kept private to a single thread.
582	*/
583	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
584	ASSERT(0);
585	return -EFSCORRUPTED;
586	}
587
588	/*
589	* Allocate a new cursor like the old one.
590	*/
591	new = cur->bc_ops->dup_cursor(cur);
592
593	/*
594	* Copy the record currently in the cursor.
595	*/
596	new->bc_rec = cur->bc_rec;
597
598	/*
599	* For each level current, re-get the buffer and copy the ptr value.
600	*/
601	for (i = 0; i < new->bc_nlevels; i++) {
602	new->bc_levels[i].ptr = cur->bc_levels[i].ptr;
603	new->bc_levels[i].ra = cur->bc_levels[i].ra;
604	bp = cur->bc_levels[i].bp;
605	if (bp) {
606	error = xfs_trans_read_buf(mp, tp,
607	xfs_btree_buftarg(cur),
608	xfs_buf_daddr(bp),
609	xfs_btree_bbsize(cur), 0, &bp,
610	cur->bc_ops->buf_ops);
611	if (xfs_metadata_is_sick(error))
612	xfs_btree_mark_sick(cur: new);
613	if (error) {
614	xfs_btree_del_cursor(cur: new, error);
615	*ncur = NULL;
616	return error;
617	}
618	}
619	new->bc_levels[i].bp = bp;
620	}
621	*ncur = new;
622	return 0;
623	}
624
625	/*
626	* XFS btree block layout and addressing:
627	*
628	* There are two types of blocks in the btree: leaf and non-leaf blocks.
629	*
630	* The leaf record start with a header then followed by records containing
631	* the values. A non-leaf block also starts with the same header, and
632	* then first contains lookup keys followed by an equal number of pointers
633	* to the btree blocks at the previous level.
634	*
635	* +--------+-------+-------+-------+-------+-------+-------+
636	* Leaf: | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
637	* +--------+-------+-------+-------+-------+-------+-------+
638	*
639	* +--------+-------+-------+-------+-------+-------+-------+
640	* Non-Leaf: | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
641	* +--------+-------+-------+-------+-------+-------+-------+
642	*
643	* The header is called struct xfs_btree_block for reasons better left unknown
644	* and comes in different versions for short (32bit) and long (64bit) block
645	* pointers. The record and key structures are defined by the btree instances
646	* and opaque to the btree core. The block pointers are simple disk endian
647	* integers, available in a short (32bit) and long (64bit) variant.
648	*
649	* The helpers below calculate the offset of a given record, key or pointer
650	* into a btree block (xfs_btree_*_offset) or return a pointer to the given
651	* record, key or pointer (xfs_btree_*_addr). Note that all addressing
652	* inside the btree block is done using indices starting at one, not zero!
653	*
654	* If XFS_BTGEO_OVERLAPPING is set, then this btree supports keys containing
655	* overlapping intervals. In such a tree, records are still sorted lowest to
656	* highest and indexed by the smallest key value that refers to the record.
657	* However, nodes are different: each pointer has two associated keys -- one
658	* indexing the lowest key available in the block(s) below (the same behavior
659	* as the key in a regular btree) and another indexing the highest key
660	* available in the block(s) below. Because records are /not/ sorted by the
661	* highest key, all leaf block updates require us to compute the highest key
662	* that matches any record in the leaf and to recursively update the high keys
663	* in the nodes going further up in the tree, if necessary. Nodes look like
664	* this:
665	*
666	* +--------+-----+-----+-----+-----+-----+-------+-------+-----+
667	* Non-Leaf: | header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
668	* +--------+-----+-----+-----+-----+-----+-------+-------+-----+
669	*
670	* To perform an interval query on an overlapped tree, perform the usual
671	* depth-first search and use the low and high keys to decide if we can skip
672	* that particular node. If a leaf node is reached, return the records that
673	* intersect the interval. Note that an interval query may return numerous
674	* entries. For a non-overlapped tree, simply search for the record associated
675	* with the lowest key and iterate forward until a non-matching record is
676	* found. Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
677	* Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
678	* more detail.
679	*
680	* Why do we care about overlapping intervals? Let's say you have a bunch of
681	* reverse mapping records on a reflink filesystem:
682	*
683	* 1: +- file A startblock B offset C length D -----------+
684	* 2: +- file E startblock F offset G length H --------------+
685	* 3: +- file I startblock F offset J length K --+
686	* 4: +- file L... --+
687	*
688	* Now say we want to map block (B+D) into file A at offset (C+D). Ideally,
689	* we'd simply increment the length of record 1. But how do we find the record
690	* that ends at (B+D-1) (i.e. record 1)? A LE lookup of (B+D-1) would return
691	* record 3 because the keys are ordered first by startblock. An interval
692	* query would return records 1 and 2 because they both overlap (B+D-1), and
693	* from that we can pick out record 1 as the appropriate left neighbor.
694	*
695	* In the non-overlapped case you can do a LE lookup and decrement the cursor
696	* because a record's interval must end before the next record.
697	*/
698
699	/*
700	* Return size of the btree block header for this btree instance.
701	*/
702	static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
703	{
704	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
705	if (xfs_has_crc(cur->bc_mp))
706	return XFS_BTREE_LBLOCK_CRC_LEN;
707	return XFS_BTREE_LBLOCK_LEN;
708	}
709	if (xfs_has_crc(cur->bc_mp))
710	return XFS_BTREE_SBLOCK_CRC_LEN;
711	return XFS_BTREE_SBLOCK_LEN;
712	}
713
714	/*
715	* Calculate offset of the n-th record in a btree block.
716	*/
717	STATIC size_t
718	xfs_btree_rec_offset(
719	struct xfs_btree_cur *cur,
720	int n)
721	{
722	return xfs_btree_block_len(cur) +
723	(n - 1) * cur->bc_ops->rec_len;
724	}
725
726	/*
727	* Calculate offset of the n-th key in a btree block.
728	*/
729	STATIC size_t
730	xfs_btree_key_offset(
731	struct xfs_btree_cur *cur,
732	int n)
733	{
734	return xfs_btree_block_len(cur) +
735	(n - 1) * cur->bc_ops->key_len;
736	}
737
738	/*
739	* Calculate offset of the n-th high key in a btree block.
740	*/
741	STATIC size_t
742	xfs_btree_high_key_offset(
743	struct xfs_btree_cur *cur,
744	int n)
745	{
746	return xfs_btree_block_len(cur) +
747	(n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
748	}
749
750	/*
751	* Calculate offset of the n-th block pointer in a btree block.
752	*/
753	STATIC size_t
754	xfs_btree_ptr_offset(
755	struct xfs_btree_cur *cur,
756	int n,
757	int level)
758	{
759	return xfs_btree_block_len(cur) +
760	cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
761	(n - 1) * cur->bc_ops->ptr_len;
762	}
763
764	/*
765	* Return a pointer to the n-th record in the btree block.
766	*/
767	union xfs_btree_rec *
768	xfs_btree_rec_addr(
769	struct xfs_btree_cur *cur,
770	int n,
771	struct xfs_btree_block *block)
772	{
773	return (union xfs_btree_rec *)
774	((char *)block + xfs_btree_rec_offset(cur, n));
775	}
776
777	/*
778	* Return a pointer to the n-th key in the btree block.
779	*/
780	union xfs_btree_key *
781	xfs_btree_key_addr(
782	struct xfs_btree_cur *cur,
783	int n,
784	struct xfs_btree_block *block)
785	{
786	return (union xfs_btree_key *)
787	((char *)block + xfs_btree_key_offset(cur, n));
788	}
789
790	/*
791	* Return a pointer to the n-th high key in the btree block.
792	*/
793	union xfs_btree_key *
794	xfs_btree_high_key_addr(
795	struct xfs_btree_cur *cur,
796	int n,
797	struct xfs_btree_block *block)
798	{
799	return (union xfs_btree_key *)
800	((char *)block + xfs_btree_high_key_offset(cur, n));
801	}
802
803	/*
804	* Return a pointer to the n-th block pointer in the btree block.
805	*/
806	union xfs_btree_ptr *
807	xfs_btree_ptr_addr(
808	struct xfs_btree_cur *cur,
809	int n,
810	struct xfs_btree_block *block)
811	{
812	int level = xfs_btree_get_level(block);
813
814	ASSERT(block->bb_level != 0);
815
816	return (union xfs_btree_ptr *)
817	((char *)block + xfs_btree_ptr_offset(cur, n, level));
818	}
819
820	struct xfs_ifork *
821	xfs_btree_ifork_ptr(
822	struct xfs_btree_cur *cur)
823	{
824	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
825
826	if (cur->bc_flags & XFS_BTREE_STAGING)
827	return cur->bc_ino.ifake->if_fork;
828	return xfs_ifork_ptr(cur->bc_ino.ip, cur->bc_ino.whichfork);
829	}
830
831	/*
832	* Get the root block which is stored in the inode.
833	*
834	* For now this btree implementation assumes the btree root is always
835	* stored in the if_broot field of an inode fork.
836	*/
837	STATIC struct xfs_btree_block *
838	xfs_btree_get_iroot(
839	struct xfs_btree_cur *cur)
840	{
841	struct xfs_ifork *ifp = xfs_btree_ifork_ptr(cur);
842
843	return (struct xfs_btree_block *)ifp->if_broot;
844	}
845
846	/*
847	* Retrieve the block pointer from the cursor at the given level.
848	* This may be an inode btree root or from a buffer.
849	*/
850	struct xfs_btree_block * /* generic btree block pointer */
851	xfs_btree_get_block(
852	struct xfs_btree_cur *cur, /* btree cursor */
853	int level, /* level in btree */
854	struct xfs_buf **bpp) /* buffer containing the block */
855	{
856	if (xfs_btree_at_iroot(cur, level)) {
857	*bpp = NULL;
858	return xfs_btree_get_iroot(cur);
859	}
860
861	*bpp = cur->bc_levels[level].bp;
862	return XFS_BUF_TO_BLOCK(*bpp);
863	}
864
865	/*
866	* Change the cursor to point to the first record at the given level.
867	* Other levels are unaffected.
868	*/
869	STATIC int /* success=1, failure=0 */
870	xfs_btree_firstrec(
871	struct xfs_btree_cur *cur, /* btree cursor */
872	int level) /* level to change */
873	{
874	struct xfs_btree_block *block; /* generic btree block pointer */
875	struct xfs_buf *bp; /* buffer containing block */
876
877	/*
878	* Get the block pointer for this level.
879	*/
880	block = xfs_btree_get_block(cur, level, bpp: &bp);
881	if (xfs_btree_check_block(cur, block, level, bp))
882	return 0;
883	/*
884	* It's empty, there is no such record.
885	*/
886	if (!block->bb_numrecs)
887	return 0;
888	/*
889	* Set the ptr value to 1, that's the first record/key.
890	*/
891	cur->bc_levels[level].ptr = 1;
892	return 1;
893	}
894
895	/*
896	* Change the cursor to point to the last record in the current block
897	* at the given level. Other levels are unaffected.
898	*/
899	STATIC int /* success=1, failure=0 */
900	xfs_btree_lastrec(
901	struct xfs_btree_cur *cur, /* btree cursor */
902	int level) /* level to change */
903	{
904	struct xfs_btree_block *block; /* generic btree block pointer */
905	struct xfs_buf *bp; /* buffer containing block */
906
907	/*
908	* Get the block pointer for this level.
909	*/
910	block = xfs_btree_get_block(cur, level, bpp: &bp);
911	if (xfs_btree_check_block(cur, block, level, bp))
912	return 0;
913	/*
914	* It's empty, there is no such record.
915	*/
916	if (!block->bb_numrecs)
917	return 0;
918	/*
919	* Set the ptr value to numrecs, that's the last record/key.
920	*/
921	cur->bc_levels[level].ptr = be16_to_cpu(block->bb_numrecs);
922	return 1;
923	}
924
925	/*
926	* Compute first and last byte offsets for the fields given.
927	* Interprets the offsets table, which contains struct field offsets.
928	*/
929	void
930	xfs_btree_offsets(
931	uint32_t fields, /* bitmask of fields */
932	const short *offsets, /* table of field offsets */
933	int nbits, /* number of bits to inspect */
934	int *first, /* output: first byte offset */
935	int *last) /* output: last byte offset */
936	{
937	int i; /* current bit number */
938	uint32_t imask; /* mask for current bit number */
939
940	ASSERT(fields != 0);
941	/*
942	* Find the lowest bit, so the first byte offset.
943	*/
944	for (i = 0, imask = 1u; ; i++, imask <<= 1) {
945	if (imask & fields) {
946	*first = offsets[i];
947	break;
948	}
949	}
950	/*
951	* Find the highest bit, so the last byte offset.
952	*/
953	for (i = nbits - 1, imask = 1u << i; ; i--, imask >>= 1) {
954	if (imask & fields) {
955	*last = offsets[i + 1] - 1;
956	break;
957	}
958	}
959	}
960
961	STATIC int
962	xfs_btree_readahead_fsblock(
963	struct xfs_btree_cur *cur,
964	int lr,
965	struct xfs_btree_block *block)
966	{
967	struct xfs_mount *mp = cur->bc_mp;
968	xfs_fsblock_t left = be64_to_cpu(block->bb_u.l.bb_leftsib);
969	xfs_fsblock_t right = be64_to_cpu(block->bb_u.l.bb_rightsib);
970	int rval = 0;
971
972	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
973	xfs_buf_readahead(mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, left),
974	mp->m_bsize, cur->bc_ops->buf_ops);
975	rval++;
976	}
977
978	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
979	xfs_buf_readahead(mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, right),
980	mp->m_bsize, cur->bc_ops->buf_ops);
981	rval++;
982	}
983
984	return rval;
985	}
986
987	STATIC int
988	xfs_btree_readahead_memblock(
989	struct xfs_btree_cur *cur,
990	int lr,
991	struct xfs_btree_block *block)
992	{
993	struct xfs_buftarg *btp = cur->bc_mem.xfbtree->target;
994	xfbno_t left = be64_to_cpu(block->bb_u.l.bb_leftsib);
995	xfbno_t right = be64_to_cpu(block->bb_u.l.bb_rightsib);
996	int rval = 0;
997
998	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
999	xfs_buf_readahead(btp, xfbno_to_daddr(left), XFBNO_BBSIZE,
1000	cur->bc_ops->buf_ops);
1001	rval++;
1002	}
1003
1004	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
1005	xfs_buf_readahead(btp, xfbno_to_daddr(right), XFBNO_BBSIZE,
1006	cur->bc_ops->buf_ops);
1007	rval++;
1008	}
1009
1010	return rval;
1011	}
1012
1013	STATIC int
1014	xfs_btree_readahead_agblock(
1015	struct xfs_btree_cur *cur,
1016	int lr,
1017	struct xfs_btree_block *block)
1018	{
1019	struct xfs_mount *mp = cur->bc_mp;
1020	xfs_agnumber_t agno = cur->bc_ag.pag->pag_agno;
1021	xfs_agblock_t left = be32_to_cpu(block->bb_u.s.bb_leftsib);
1022	xfs_agblock_t right = be32_to_cpu(block->bb_u.s.bb_rightsib);
1023	int rval = 0;
1024
1025	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
1026	xfs_buf_readahead(mp->m_ddev_targp,
1027	XFS_AGB_TO_DADDR(mp, agno, left),
1028	mp->m_bsize, cur->bc_ops->buf_ops);
1029	rval++;
1030	}
1031
1032	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
1033	xfs_buf_readahead(mp->m_ddev_targp,
1034	XFS_AGB_TO_DADDR(mp, agno, right),
1035	mp->m_bsize, cur->bc_ops->buf_ops);
1036	rval++;
1037	}
1038
1039	return rval;
1040	}
1041
1042	/*
1043	* Read-ahead btree blocks, at the given level.
1044	* Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
1045	*/
1046	STATIC int
1047	xfs_btree_readahead(
1048	struct xfs_btree_cur *cur, /* btree cursor */
1049	int lev, /* level in btree */
1050	int lr) /* left/right bits */
1051	{
1052	struct xfs_btree_block *block;
1053
1054	/*
1055	* No readahead needed if we are at the root level and the
1056	* btree root is stored in the inode.
1057	*/
1058	if (xfs_btree_at_iroot(cur, lev))
1059	return 0;
1060
1061	if ((cur->bc_levels[lev].ra | lr) == cur->bc_levels[lev].ra)
1062	return 0;
1063
1064	cur->bc_levels[lev].ra |= lr;
1065	block = XFS_BUF_TO_BLOCK(cur->bc_levels[lev].bp);
1066
1067	switch (cur->bc_ops->type) {
1068	case XFS_BTREE_TYPE_AG:
1069	return xfs_btree_readahead_agblock(cur, lr, block);
1070	case XFS_BTREE_TYPE_INODE:
1071	return xfs_btree_readahead_fsblock(cur, lr, block);
1072	case XFS_BTREE_TYPE_MEM:
1073	return xfs_btree_readahead_memblock(cur, lr, block);
1074	default:
1075	ASSERT(0);
1076	return 0;
1077	}
1078	}
1079
1080	STATIC int
1081	xfs_btree_ptr_to_daddr(
1082	struct xfs_btree_cur *cur,
1083	const union xfs_btree_ptr *ptr,
1084	xfs_daddr_t *daddr)
1085	{
1086	int error;
1087
1088	error = xfs_btree_check_ptr(cur, ptr, index: 0, level: 1);
1089	if (error)
1090	return error;
1091
1092	switch (cur->bc_ops->type) {
1093	case XFS_BTREE_TYPE_AG:
1094	*daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1095	be32_to_cpu(ptr->s));
1096	break;
1097	case XFS_BTREE_TYPE_INODE:
1098	*daddr = XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
1099	break;
1100	case XFS_BTREE_TYPE_MEM:
1101	*daddr = xfbno_to_daddr(be64_to_cpu(ptr->l));
1102	break;
1103	}
1104	return 0;
1105	}
1106
1107	/*
1108	* Readahead @count btree blocks at the given @ptr location.
1109	*
1110	* We don't need to care about long or short form btrees here as we have a
1111	* method of converting the ptr directly to a daddr available to us.
1112	*/
1113	STATIC void
1114	xfs_btree_readahead_ptr(
1115	struct xfs_btree_cur *cur,
1116	union xfs_btree_ptr *ptr,
1117	xfs_extlen_t count)
1118	{
1119	xfs_daddr_t daddr;
1120
1121	if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
1122	return;
1123	xfs_buf_readahead(xfs_btree_buftarg(cur), daddr,
1124	xfs_btree_bbsize(cur) * count,
1125	cur->bc_ops->buf_ops);
1126	}
1127
1128	/*
1129	* Set the buffer for level "lev" in the cursor to bp, releasing
1130	* any previous buffer.
1131	*/
1132	STATIC void
1133	xfs_btree_setbuf(
1134	struct xfs_btree_cur *cur, /* btree cursor */
1135	int lev, /* level in btree */
1136	struct xfs_buf *bp) /* new buffer to set */
1137	{
1138	struct xfs_btree_block *b; /* btree block */
1139
1140	if (cur->bc_levels[lev].bp)
1141	xfs_trans_brelse(cur->bc_tp, cur->bc_levels[lev].bp);
1142	cur->bc_levels[lev].bp = bp;
1143	cur->bc_levels[lev].ra = 0;
1144
1145	b = XFS_BUF_TO_BLOCK(bp);
1146	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1147	if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1148	cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1149	if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1150	cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1151	} else {
1152	if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1153	cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1154	if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1155	cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1156	}
1157	}
1158
1159	bool
1160	xfs_btree_ptr_is_null(
1161	struct xfs_btree_cur *cur,
1162	const union xfs_btree_ptr *ptr)
1163	{
1164	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1165	return ptr->l == cpu_to_be64(NULLFSBLOCK);
1166	else
1167	return ptr->s == cpu_to_be32(NULLAGBLOCK);
1168	}
1169
1170	void
1171	xfs_btree_set_ptr_null(
1172	struct xfs_btree_cur *cur,
1173	union xfs_btree_ptr *ptr)
1174	{
1175	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1176	ptr->l = cpu_to_be64(NULLFSBLOCK);
1177	else
1178	ptr->s = cpu_to_be32(NULLAGBLOCK);
1179	}
1180
1181	static inline bool
1182	xfs_btree_ptrs_equal(
1183	struct xfs_btree_cur *cur,
1184	union xfs_btree_ptr *ptr1,
1185	union xfs_btree_ptr *ptr2)
1186	{
1187	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1188	return ptr1->l == ptr2->l;
1189	return ptr1->s == ptr2->s;
1190	}
1191
1192	/*
1193	* Get/set/init sibling pointers
1194	*/
1195	void
1196	xfs_btree_get_sibling(
1197	struct xfs_btree_cur *cur,
1198	struct xfs_btree_block *block,
1199	union xfs_btree_ptr *ptr,
1200	int lr)
1201	{
1202	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1203
1204	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1205	if (lr == XFS_BB_RIGHTSIB)
1206	ptr->l = block->bb_u.l.bb_rightsib;
1207	else
1208	ptr->l = block->bb_u.l.bb_leftsib;
1209	} else {
1210	if (lr == XFS_BB_RIGHTSIB)
1211	ptr->s = block->bb_u.s.bb_rightsib;
1212	else
1213	ptr->s = block->bb_u.s.bb_leftsib;
1214	}
1215	}
1216
1217	void
1218	xfs_btree_set_sibling(
1219	struct xfs_btree_cur *cur,
1220	struct xfs_btree_block *block,
1221	const union xfs_btree_ptr *ptr,
1222	int lr)
1223	{
1224	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1225
1226	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1227	if (lr == XFS_BB_RIGHTSIB)
1228	block->bb_u.l.bb_rightsib = ptr->l;
1229	else
1230	block->bb_u.l.bb_leftsib = ptr->l;
1231	} else {
1232	if (lr == XFS_BB_RIGHTSIB)
1233	block->bb_u.s.bb_rightsib = ptr->s;
1234	else
1235	block->bb_u.s.bb_leftsib = ptr->s;
1236	}
1237	}
1238
1239	static void
1240	__xfs_btree_init_block(
1241	struct xfs_mount *mp,
1242	struct xfs_btree_block *buf,
1243	const struct xfs_btree_ops *ops,
1244	xfs_daddr_t blkno,
1245	__u16 level,
1246	__u16 numrecs,
1247	__u64 owner)
1248	{
1249	bool crc = xfs_has_crc(mp);
1250	__u32 magic = xfs_btree_magic(mp, ops);
1251
1252	buf->bb_magic = cpu_to_be32(magic);
1253	buf->bb_level = cpu_to_be16(level);
1254	buf->bb_numrecs = cpu_to_be16(numrecs);
1255
1256	if (ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1257	buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1258	buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1259	if (crc) {
1260	buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1261	buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1262	uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1263	buf->bb_u.l.bb_pad = 0;
1264	buf->bb_u.l.bb_lsn = 0;
1265	}
1266	} else {
1267	buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1268	buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1269	if (crc) {
1270	buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1271	/* owner is a 32 bit value on short blocks */
1272	buf->bb_u.s.bb_owner = cpu_to_be32((__u32)owner);
1273	uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1274	buf->bb_u.s.bb_lsn = 0;
1275	}
1276	}
1277	}
1278
1279	void
1280	xfs_btree_init_block(
1281	struct xfs_mount *mp,
1282	struct xfs_btree_block *block,
1283	const struct xfs_btree_ops *ops,
1284	__u16 level,
1285	__u16 numrecs,
1286	__u64 owner)
1287	{
1288	__xfs_btree_init_block(mp, block, ops, XFS_BUF_DADDR_NULL, level,
1289	numrecs, owner);
1290	}
1291
1292	void
1293	xfs_btree_init_buf(
1294	struct xfs_mount *mp,
1295	struct xfs_buf *bp,
1296	const struct xfs_btree_ops *ops,
1297	__u16 level,
1298	__u16 numrecs,
1299	__u64 owner)
1300	{
1301	__xfs_btree_init_block(mp, XFS_BUF_TO_BLOCK(bp), ops,
1302	xfs_buf_daddr(bp), level, numrecs, owner);
1303	bp->b_ops = ops->buf_ops;
1304	}
1305
1306	static inline __u64
1307	xfs_btree_owner(
1308	struct xfs_btree_cur *cur)
1309	{
1310	switch (cur->bc_ops->type) {
1311	case XFS_BTREE_TYPE_MEM:
1312	return cur->bc_mem.xfbtree->owner;
1313	case XFS_BTREE_TYPE_INODE:
1314	return cur->bc_ino.ip->i_ino;
1315	case XFS_BTREE_TYPE_AG:
1316	return cur->bc_ag.pag->pag_agno;
1317	default:
1318	ASSERT(0);
1319	return 0;
1320	}
1321	}
1322
1323	void
1324	xfs_btree_init_block_cur(
1325	struct xfs_btree_cur *cur,
1326	struct xfs_buf *bp,
1327	int level,
1328	int numrecs)
1329	{
1330	xfs_btree_init_buf(cur->bc_mp, bp, cur->bc_ops, level, numrecs,
1331	xfs_btree_owner(cur));
1332	}
1333
1334	/*
1335	* Return true if ptr is the last record in the btree and
1336	* we need to track updates to this record. The decision
1337	* will be further refined in the update_lastrec method.
1338	*/
1339	STATIC int
1340	xfs_btree_is_lastrec(
1341	struct xfs_btree_cur *cur,
1342	struct xfs_btree_block *block,
1343	int level)
1344	{
1345	union xfs_btree_ptr ptr;
1346
1347	if (level > 0)
1348	return 0;
1349	if (!(cur->bc_ops->geom_flags & XFS_BTGEO_LASTREC_UPDATE))
1350	return 0;
1351
1352	xfs_btree_get_sibling(cur, block, ptr: &ptr, XFS_BB_RIGHTSIB);
1353	if (!xfs_btree_ptr_is_null(cur, &ptr))
1354	return 0;
1355	return 1;
1356	}
1357
1358	STATIC void
1359	xfs_btree_buf_to_ptr(
1360	struct xfs_btree_cur *cur,
1361	struct xfs_buf *bp,
1362	union xfs_btree_ptr *ptr)
1363	{
1364	switch (cur->bc_ops->type) {
1365	case XFS_BTREE_TYPE_AG:
1366	ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1367	xfs_buf_daddr(bp)));
1368	break;
1369	case XFS_BTREE_TYPE_INODE:
1370	ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1371	xfs_buf_daddr(bp)));
1372	break;
1373	case XFS_BTREE_TYPE_MEM:
1374	ptr->l = cpu_to_be64(xfs_daddr_to_xfbno(xfs_buf_daddr(bp)));
1375	break;
1376	}
1377	}
1378
1379	static inline void
1380	xfs_btree_set_refs(
1381	struct xfs_btree_cur *cur,
1382	struct xfs_buf *bp)
1383	{
1384	xfs_buf_set_ref(bp, cur->bc_ops->lru_refs);
1385	}
1386
1387	int
1388	xfs_btree_get_buf_block(
1389	struct xfs_btree_cur *cur,
1390	const union xfs_btree_ptr *ptr,
1391	struct xfs_btree_block **block,
1392	struct xfs_buf **bpp)
1393	{
1394	xfs_daddr_t d;
1395	int error;
1396
1397	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1398	if (error)
1399	return error;
1400	error = xfs_trans_get_buf(cur->bc_tp, xfs_btree_buftarg(cur), d,
1401	xfs_btree_bbsize(cur), 0, bpp);
1402	if (error)
1403	return error;
1404
1405	(*bpp)->b_ops = cur->bc_ops->buf_ops;
1406	*block = XFS_BUF_TO_BLOCK(*bpp);
1407	return 0;
1408	}
1409
1410	/*
1411	* Read in the buffer at the given ptr and return the buffer and
1412	* the block pointer within the buffer.
1413	*/
1414	int
1415	xfs_btree_read_buf_block(
1416	struct xfs_btree_cur *cur,
1417	const union xfs_btree_ptr *ptr,
1418	int flags,
1419	struct xfs_btree_block **block,
1420	struct xfs_buf **bpp)
1421	{
1422	struct xfs_mount *mp = cur->bc_mp;
1423	xfs_daddr_t d;
1424	int error;
1425
1426	/* need to sort out how callers deal with failures first */
1427	ASSERT(!(flags & XBF_TRYLOCK));
1428
1429	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1430	if (error)
1431	return error;
1432	error = xfs_trans_read_buf(mp, cur->bc_tp, xfs_btree_buftarg(cur), d,
1433	xfs_btree_bbsize(cur), flags, bpp,
1434	cur->bc_ops->buf_ops);
1435	if (xfs_metadata_is_sick(error))
1436	xfs_btree_mark_sick(cur);
1437	if (error)
1438	return error;
1439
1440	xfs_btree_set_refs(cur, bp: *bpp);
1441	*block = XFS_BUF_TO_BLOCK(*bpp);
1442	return 0;
1443	}
1444
1445	/*
1446	* Copy keys from one btree block to another.
1447	*/
1448	void
1449	xfs_btree_copy_keys(
1450	struct xfs_btree_cur *cur,
1451	union xfs_btree_key *dst_key,
1452	const union xfs_btree_key *src_key,
1453	int numkeys)
1454	{
1455	ASSERT(numkeys >= 0);
1456	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1457	}
1458
1459	/*
1460	* Copy records from one btree block to another.
1461	*/
1462	STATIC void
1463	xfs_btree_copy_recs(
1464	struct xfs_btree_cur *cur,
1465	union xfs_btree_rec *dst_rec,
1466	union xfs_btree_rec *src_rec,
1467	int numrecs)
1468	{
1469	ASSERT(numrecs >= 0);
1470	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1471	}
1472
1473	/*
1474	* Copy block pointers from one btree block to another.
1475	*/
1476	void
1477	xfs_btree_copy_ptrs(
1478	struct xfs_btree_cur *cur,
1479	union xfs_btree_ptr *dst_ptr,
1480	const union xfs_btree_ptr *src_ptr,
1481	int numptrs)
1482	{
1483	ASSERT(numptrs >= 0);
1484	memcpy(dst_ptr, src_ptr, numptrs * cur->bc_ops->ptr_len);
1485	}
1486
1487	/*
1488	* Shift keys one index left/right inside a single btree block.
1489	*/
1490	STATIC void
1491	xfs_btree_shift_keys(
1492	struct xfs_btree_cur *cur,
1493	union xfs_btree_key *key,
1494	int dir,
1495	int numkeys)
1496	{
1497	char *dst_key;
1498
1499	ASSERT(numkeys >= 0);
1500	ASSERT(dir == 1 || dir == -1);
1501
1502	dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1503	memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1504	}
1505
1506	/*
1507	* Shift records one index left/right inside a single btree block.
1508	*/
1509	STATIC void
1510	xfs_btree_shift_recs(
1511	struct xfs_btree_cur *cur,
1512	union xfs_btree_rec *rec,
1513	int dir,
1514	int numrecs)
1515	{
1516	char *dst_rec;
1517
1518	ASSERT(numrecs >= 0);
1519	ASSERT(dir == 1 || dir == -1);
1520
1521	dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1522	memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1523	}
1524
1525	/*
1526	* Shift block pointers one index left/right inside a single btree block.
1527	*/
1528	STATIC void
1529	xfs_btree_shift_ptrs(
1530	struct xfs_btree_cur *cur,
1531	union xfs_btree_ptr *ptr,
1532	int dir,
1533	int numptrs)
1534	{
1535	char *dst_ptr;
1536
1537	ASSERT(numptrs >= 0);
1538	ASSERT(dir == 1 || dir == -1);
1539
1540	dst_ptr = (char *)ptr + (dir * cur->bc_ops->ptr_len);
1541	memmove(dst_ptr, ptr, numptrs * cur->bc_ops->ptr_len);
1542	}
1543
1544	/*
1545	* Log key values from the btree block.
1546	*/
1547	STATIC void
1548	xfs_btree_log_keys(
1549	struct xfs_btree_cur *cur,
1550	struct xfs_buf *bp,
1551	int first,
1552	int last)
1553	{
1554
1555	if (bp) {
1556	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1557	xfs_trans_log_buf(cur->bc_tp, bp,
1558	xfs_btree_key_offset(cur, first),
1559	xfs_btree_key_offset(cur, last + 1) - 1);
1560	} else {
1561	xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1562	xfs_ilog_fbroot(w: cur->bc_ino.whichfork));
1563	}
1564	}
1565
1566	/*
1567	* Log record values from the btree block.
1568	*/
1569	void
1570	xfs_btree_log_recs(
1571	struct xfs_btree_cur *cur,
1572	struct xfs_buf *bp,
1573	int first,
1574	int last)
1575	{
1576
1577	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1578	xfs_trans_log_buf(cur->bc_tp, bp,
1579	xfs_btree_rec_offset(cur, first),
1580	xfs_btree_rec_offset(cur, last + 1) - 1);
1581
1582	}
1583
1584	/*
1585	* Log block pointer fields from a btree block (nonleaf).
1586	*/
1587	STATIC void
1588	xfs_btree_log_ptrs(
1589	struct xfs_btree_cur *cur, /* btree cursor */
1590	struct xfs_buf *bp, /* buffer containing btree block */
1591	int first, /* index of first pointer to log */
1592	int last) /* index of last pointer to log */
1593	{
1594
1595	if (bp) {
1596	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
1597	int level = xfs_btree_get_level(block);
1598
1599	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1600	xfs_trans_log_buf(cur->bc_tp, bp,
1601	xfs_btree_ptr_offset(cur, first, level),
1602	xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1603	} else {
1604	xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1605	xfs_ilog_fbroot(w: cur->bc_ino.whichfork));
1606	}
1607
1608	}
1609
1610	/*
1611	* Log fields from a btree block header.
1612	*/
1613	void
1614	xfs_btree_log_block(
1615	struct xfs_btree_cur *cur, /* btree cursor */
1616	struct xfs_buf *bp, /* buffer containing btree block */
1617	uint32_t fields) /* mask of fields: XFS_BB_... */
1618	{
1619	int first; /* first byte offset logged */
1620	int last; /* last byte offset logged */
1621	static const short soffsets[] = { /* table of offsets (short) */
1622	offsetof(struct xfs_btree_block, bb_magic),
1623	offsetof(struct xfs_btree_block, bb_level),
1624	offsetof(struct xfs_btree_block, bb_numrecs),
1625	offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1626	offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1627	offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1628	offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1629	offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1630	offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1631	offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1632	XFS_BTREE_SBLOCK_CRC_LEN
1633	};
1634	static const short loffsets[] = { /* table of offsets (long) */
1635	offsetof(struct xfs_btree_block, bb_magic),
1636	offsetof(struct xfs_btree_block, bb_level),
1637	offsetof(struct xfs_btree_block, bb_numrecs),
1638	offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1639	offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1640	offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1641	offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1642	offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1643	offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1644	offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1645	offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1646	XFS_BTREE_LBLOCK_CRC_LEN
1647	};
1648
1649	if (bp) {
1650	int nbits;
1651
1652	if (xfs_has_crc(cur->bc_mp)) {
1653	/*
1654	* We don't log the CRC when updating a btree
1655	* block but instead recreate it during log
1656	* recovery. As the log buffers have checksums
1657	* of their own this is safe and avoids logging a crc
1658	* update in a lot of places.
1659	*/
1660	if (fields == XFS_BB_ALL_BITS)
1661	fields = XFS_BB_ALL_BITS_CRC;
1662	nbits = XFS_BB_NUM_BITS_CRC;
1663	} else {
1664	nbits = XFS_BB_NUM_BITS;
1665	}
1666	xfs_btree_offsets(fields,
1667	(cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) ?
1668	loffsets : soffsets,
1669	nbits, &first, &last);
1670	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1671	xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1672	} else {
1673	xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1674	xfs_ilog_fbroot(w: cur->bc_ino.whichfork));
1675	}
1676	}
1677
1678	/*
1679	* Increment cursor by one record at the level.
1680	* For nonzero levels the leaf-ward information is untouched.
1681	*/
1682	int /* error */
1683	xfs_btree_increment(
1684	struct xfs_btree_cur *cur,
1685	int level,
1686	int *stat) /* success/failure */
1687	{
1688	struct xfs_btree_block *block;
1689	union xfs_btree_ptr ptr;
1690	struct xfs_buf *bp;
1691	int error; /* error return value */
1692	int lev;
1693
1694	ASSERT(level < cur->bc_nlevels);
1695
1696	/* Read-ahead to the right at this level. */
1697	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1698
1699	/* Get a pointer to the btree block. */
1700	block = xfs_btree_get_block(cur, level, bpp: &bp);
1701
1702	#ifdef DEBUG
1703	error = xfs_btree_check_block(cur, block, level, bp);
1704	if (error)
1705	goto error0;
1706	#endif
1707
1708	/* We're done if we remain in the block after the increment. */
1709	if (++cur->bc_levels[level].ptr <= xfs_btree_get_numrecs(block))
1710	goto out1;
1711
1712	/* Fail if we just went off the right edge of the tree. */
1713	xfs_btree_get_sibling(cur, block, ptr: &ptr, XFS_BB_RIGHTSIB);
1714	if (xfs_btree_ptr_is_null(cur, &ptr))
1715	goto out0;
1716
1717	XFS_BTREE_STATS_INC(cur, increment);
1718
1719	/*
1720	* March up the tree incrementing pointers.
1721	* Stop when we don't go off the right edge of a block.
1722	*/
1723	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1724	block = xfs_btree_get_block(cur, level: lev, bpp: &bp);
1725
1726	#ifdef DEBUG
1727	error = xfs_btree_check_block(cur, block, lev, bp);
1728	if (error)
1729	goto error0;
1730	#endif
1731
1732	if (++cur->bc_levels[lev].ptr <= xfs_btree_get_numrecs(block))
1733	break;
1734
1735	/* Read-ahead the right block for the next loop. */
1736	xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1737	}
1738
1739	/*
1740	* If we went off the root then we are either seriously
1741	* confused or have the tree root in an inode.
1742	*/
1743	if (lev == cur->bc_nlevels) {
1744	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE)
1745	goto out0;
1746	ASSERT(0);
1747	xfs_btree_mark_sick(cur);
1748	error = -EFSCORRUPTED;
1749	goto error0;
1750	}
1751	ASSERT(lev < cur->bc_nlevels);
1752
1753	/*
1754	* Now walk back down the tree, fixing up the cursor's buffer
1755	* pointers and key numbers.
1756	*/
1757	for (block = xfs_btree_get_block(cur, level: lev, bpp: &bp); lev > level; ) {
1758	union xfs_btree_ptr *ptrp;
1759
1760	ptrp = xfs_btree_ptr_addr(cur, n: cur->bc_levels[lev].ptr, block);
1761	--lev;
1762	error = xfs_btree_read_buf_block(cur, ptr: ptrp, flags: 0, block: &block, bpp: &bp);
1763	if (error)
1764	goto error0;
1765
1766	xfs_btree_setbuf(cur, lev, bp);
1767	cur->bc_levels[lev].ptr = 1;
1768	}
1769	out1:
1770	*stat = 1;
1771	return 0;
1772
1773	out0:
1774	*stat = 0;
1775	return 0;
1776
1777	error0:
1778	return error;
1779	}
1780
1781	/*
1782	* Decrement cursor by one record at the level.
1783	* For nonzero levels the leaf-ward information is untouched.
1784	*/
1785	int /* error */
1786	xfs_btree_decrement(
1787	struct xfs_btree_cur *cur,
1788	int level,
1789	int *stat) /* success/failure */
1790	{
1791	struct xfs_btree_block *block;
1792	struct xfs_buf *bp;
1793	int error; /* error return value */
1794	int lev;
1795	union xfs_btree_ptr ptr;
1796
1797	ASSERT(level < cur->bc_nlevels);
1798
1799	/* Read-ahead to the left at this level. */
1800	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1801
1802	/* We're done if we remain in the block after the decrement. */
1803	if (--cur->bc_levels[level].ptr > 0)
1804	goto out1;
1805
1806	/* Get a pointer to the btree block. */
1807	block = xfs_btree_get_block(cur, level, bpp: &bp);
1808
1809	#ifdef DEBUG
1810	error = xfs_btree_check_block(cur, block, level, bp);
1811	if (error)
1812	goto error0;
1813	#endif
1814
1815	/* Fail if we just went off the left edge of the tree. */
1816	xfs_btree_get_sibling(cur, block, ptr: &ptr, XFS_BB_LEFTSIB);
1817	if (xfs_btree_ptr_is_null(cur, &ptr))
1818	goto out0;
1819
1820	XFS_BTREE_STATS_INC(cur, decrement);
1821
1822	/*
1823	* March up the tree decrementing pointers.
1824	* Stop when we don't go off the left edge of a block.
1825	*/
1826	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1827	if (--cur->bc_levels[lev].ptr > 0)
1828	break;
1829	/* Read-ahead the left block for the next loop. */
1830	xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1831	}
1832
1833	/*
1834	* If we went off the root then we are seriously confused.
1835	* or the root of the tree is in an inode.
1836	*/
1837	if (lev == cur->bc_nlevels) {
1838	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE)
1839	goto out0;
1840	ASSERT(0);
1841	xfs_btree_mark_sick(cur);
1842	error = -EFSCORRUPTED;
1843	goto error0;
1844	}
1845	ASSERT(lev < cur->bc_nlevels);
1846
1847	/*
1848	* Now walk back down the tree, fixing up the cursor's buffer
1849	* pointers and key numbers.
1850	*/
1851	for (block = xfs_btree_get_block(cur, level: lev, bpp: &bp); lev > level; ) {
1852	union xfs_btree_ptr *ptrp;
1853
1854	ptrp = xfs_btree_ptr_addr(cur, n: cur->bc_levels[lev].ptr, block);
1855	--lev;
1856	error = xfs_btree_read_buf_block(cur, ptr: ptrp, flags: 0, block: &block, bpp: &bp);
1857	if (error)
1858	goto error0;
1859	xfs_btree_setbuf(cur, lev, bp);
1860	cur->bc_levels[lev].ptr = xfs_btree_get_numrecs(block);
1861	}
1862	out1:
1863	*stat = 1;
1864	return 0;
1865
1866	out0:
1867	*stat = 0;
1868	return 0;
1869
1870	error0:
1871	return error;
1872	}
1873
1874	/*
1875	* Check the btree block owner now that we have the context to know who the
1876	* real owner is.
1877	*/
1878	static inline xfs_failaddr_t
1879	xfs_btree_check_block_owner(
1880	struct xfs_btree_cur *cur,
1881	struct xfs_btree_block *block)
1882	{
1883	__u64 owner;
1884
1885	if (!xfs_has_crc(cur->bc_mp) ||
1886	(cur->bc_flags & XFS_BTREE_BMBT_INVALID_OWNER))
1887	return NULL;
1888
1889	owner = xfs_btree_owner(cur);
1890	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1891	if (be64_to_cpu(block->bb_u.l.bb_owner) != owner)
1892	return __this_address;
1893	} else {
1894	if (be32_to_cpu(block->bb_u.s.bb_owner) != owner)
1895	return __this_address;
1896	}
1897
1898	return NULL;
1899	}
1900
1901	int
1902	xfs_btree_lookup_get_block(
1903	struct xfs_btree_cur *cur, /* btree cursor */
1904	int level, /* level in the btree */
1905	const union xfs_btree_ptr *pp, /* ptr to btree block */
1906	struct xfs_btree_block **blkp) /* return btree block */
1907	{
1908	struct xfs_buf *bp; /* buffer pointer for btree block */
1909	xfs_daddr_t daddr;
1910	int error = 0;
1911
1912	/* special case the root block if in an inode */
1913	if (xfs_btree_at_iroot(cur, level)) {
1914	*blkp = xfs_btree_get_iroot(cur);
1915	return 0;
1916	}
1917
1918	/*
1919	* If the old buffer at this level for the disk address we are
1920	* looking for re-use it.
1921	*
1922	* Otherwise throw it away and get a new one.
1923	*/
1924	bp = cur->bc_levels[level].bp;
1925	error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1926	if (error)
1927	return error;
1928	if (bp && xfs_buf_daddr(bp) == daddr) {
1929	*blkp = XFS_BUF_TO_BLOCK(bp);
1930	return 0;
1931	}
1932
1933	error = xfs_btree_read_buf_block(cur, ptr: pp, flags: 0, block: blkp, bpp: &bp);
1934	if (error)
1935	return error;
1936
1937	/* Check the inode owner since the verifiers don't. */
1938	if (xfs_btree_check_block_owner(cur, *blkp) != NULL)
1939	goto out_bad;
1940
1941	/* Did we get the level we were looking for? */
1942	if (be16_to_cpu((*blkp)->bb_level) != level)
1943	goto out_bad;
1944
1945	/* Check that internal nodes have at least one record. */
1946	if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1947	goto out_bad;
1948
1949	xfs_btree_setbuf(cur, level, bp);
1950	return 0;
1951
1952	out_bad:
1953	*blkp = NULL;
1954	xfs_buf_mark_corrupt(bp);
1955	xfs_trans_brelse(cur->bc_tp, bp);
1956	xfs_btree_mark_sick(cur);
1957	return -EFSCORRUPTED;
1958	}
1959
1960	/*
1961	* Get current search key. For level 0 we don't actually have a key
1962	* structure so we make one up from the record. For all other levels
1963	* we just return the right key.
1964	*/
1965	STATIC union xfs_btree_key *
1966	xfs_lookup_get_search_key(
1967	struct xfs_btree_cur *cur,
1968	int level,
1969	int keyno,
1970	struct xfs_btree_block *block,
1971	union xfs_btree_key *kp)
1972	{
1973	if (level == 0) {
1974	cur->bc_ops->init_key_from_rec(kp,
1975	xfs_btree_rec_addr(cur, n: keyno, block));
1976	return kp;
1977	}
1978
1979	return xfs_btree_key_addr(cur, n: keyno, block);
1980	}
1981
1982	/*
1983	* Initialize a pointer to the root block.
1984	*/
1985	void
1986	xfs_btree_init_ptr_from_cur(
1987	struct xfs_btree_cur *cur,
1988	union xfs_btree_ptr *ptr)
1989	{
1990	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE) {
1991	/*
1992	* Inode-rooted btrees call xfs_btree_get_iroot to find the root
1993	* in xfs_btree_lookup_get_block and don't need a pointer here.
1994	*/
1995	ptr->l = 0;
1996	} else if (cur->bc_flags & XFS_BTREE_STAGING) {
1997	ptr->s = cpu_to_be32(cur->bc_ag.afake->af_root);
1998	} else {
1999	cur->bc_ops->init_ptr_from_cur(cur, ptr);
2000	}
2001	}
2002
2003	/*
2004	* Lookup the record. The cursor is made to point to it, based on dir.
2005	* stat is set to 0 if can't find any such record, 1 for success.
2006	*/
2007	int /* error */
2008	xfs_btree_lookup(
2009	struct xfs_btree_cur *cur, /* btree cursor */
2010	xfs_lookup_t dir, /* <=, ==, or >= */
2011	int *stat) /* success/failure */
2012	{
2013	struct xfs_btree_block *block; /* current btree block */
2014	int64_t diff; /* difference for the current key */
2015	int error; /* error return value */
2016	int keyno; /* current key number */
2017	int level; /* level in the btree */
2018	union xfs_btree_ptr *pp; /* ptr to btree block */
2019	union xfs_btree_ptr ptr; /* ptr to btree block */
2020
2021	XFS_BTREE_STATS_INC(cur, lookup);
2022
2023	/* No such thing as a zero-level tree. */
2024	if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0)) {
2025	xfs_btree_mark_sick(cur);
2026	return -EFSCORRUPTED;
2027	}
2028
2029	block = NULL;
2030	keyno = 0;
2031
2032	/* initialise start pointer from cursor */
2033	xfs_btree_init_ptr_from_cur(cur, ptr: &ptr);
2034	pp = &ptr;
2035
2036	/*
2037	* Iterate over each level in the btree, starting at the root.
2038	* For each level above the leaves, find the key we need, based
2039	* on the lookup record, then follow the corresponding block
2040	* pointer down to the next level.
2041	*/
2042	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
2043	/* Get the block we need to do the lookup on. */
2044	error = xfs_btree_lookup_get_block(cur, level, pp, blkp: &block);
2045	if (error)
2046	goto error0;
2047
2048	if (diff == 0) {
2049	/*
2050	* If we already had a key match at a higher level, we
2051	* know we need to use the first entry in this block.
2052	*/
2053	keyno = 1;
2054	} else {
2055	/* Otherwise search this block. Do a binary search. */
2056
2057	int high; /* high entry number */
2058	int low; /* low entry number */
2059
2060	/* Set low and high entry numbers, 1-based. */
2061	low = 1;
2062	high = xfs_btree_get_numrecs(block);
2063	if (!high) {
2064	/* Block is empty, must be an empty leaf. */
2065	if (level != 0 || cur->bc_nlevels != 1) {
2066	XFS_CORRUPTION_ERROR(__func__,
2067	XFS_ERRLEVEL_LOW,
2068	cur->bc_mp, block,
2069	sizeof(*block));
2070	xfs_btree_mark_sick(cur);
2071	return -EFSCORRUPTED;
2072	}
2073
2074	cur->bc_levels[0].ptr = dir != XFS_LOOKUP_LE;
2075	*stat = 0;
2076	return 0;
2077	}
2078
2079	/* Binary search the block. */
2080	while (low <= high) {
2081	union xfs_btree_key key;
2082	union xfs_btree_key *kp;
2083
2084	XFS_BTREE_STATS_INC(cur, compare);
2085
2086	/* keyno is average of low and high. */
2087	keyno = (low + high) >> 1;
2088
2089	/* Get current search key */
2090	kp = xfs_lookup_get_search_key(cur, level,
2091	keyno, block, &key);
2092
2093	/*
2094	* Compute difference to get next direction:
2095	* - less than, move right
2096	* - greater than, move left
2097	* - equal, we're done
2098	*/
2099	diff = cur->bc_ops->key_diff(cur, kp);
2100	if (diff < 0)
2101	low = keyno + 1;
2102	else if (diff > 0)
2103	high = keyno - 1;
2104	else
2105	break;
2106	}
2107	}
2108
2109	/*
2110	* If there are more levels, set up for the next level
2111	* by getting the block number and filling in the cursor.
2112	*/
2113	if (level > 0) {
2114	/*
2115	* If we moved left, need the previous key number,
2116	* unless there isn't one.
2117	*/
2118	if (diff > 0 && --keyno < 1)
2119	keyno = 1;
2120	pp = xfs_btree_ptr_addr(cur, n: keyno, block);
2121
2122	error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
2123	if (error)
2124	goto error0;
2125
2126	cur->bc_levels[level].ptr = keyno;
2127	}
2128	}
2129
2130	/* Done with the search. See if we need to adjust the results. */
2131	if (dir != XFS_LOOKUP_LE && diff < 0) {
2132	keyno++;
2133	/*
2134	* If ge search and we went off the end of the block, but it's
2135	* not the last block, we're in the wrong block.
2136	*/
2137	xfs_btree_get_sibling(cur, block, ptr: &ptr, XFS_BB_RIGHTSIB);
2138	if (dir == XFS_LOOKUP_GE &&
2139	keyno > xfs_btree_get_numrecs(block) &&
2140	!xfs_btree_ptr_is_null(cur, &ptr)) {
2141	int i;
2142
2143	cur->bc_levels[0].ptr = keyno;
2144	error = xfs_btree_increment(cur, level: 0, stat: &i);
2145	if (error)
2146	goto error0;
2147	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
2148	xfs_btree_mark_sick(cur);
2149	return -EFSCORRUPTED;
2150	}
2151	*stat = 1;
2152	return 0;
2153	}
2154	} else if (dir == XFS_LOOKUP_LE && diff > 0)
2155	keyno--;
2156	cur->bc_levels[0].ptr = keyno;
2157
2158	/* Return if we succeeded or not. */
2159	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
2160	*stat = 0;
2161	else if (dir != XFS_LOOKUP_EQ || diff == 0)
2162	*stat = 1;
2163	else
2164	*stat = 0;
2165	return 0;
2166
2167	error0:
2168	return error;
2169	}
2170
2171	/* Find the high key storage area from a regular key. */
2172	union xfs_btree_key *
2173	xfs_btree_high_key_from_key(
2174	struct xfs_btree_cur *cur,
2175	union xfs_btree_key *key)
2176	{
2177	ASSERT(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING);
2178	return (union xfs_btree_key *)((char *)key +
2179	(cur->bc_ops->key_len / 2));
2180	}
2181
2182	/* Determine the low (and high if overlapped) keys of a leaf block */
2183	STATIC void
2184	xfs_btree_get_leaf_keys(
2185	struct xfs_btree_cur *cur,
2186	struct xfs_btree_block *block,
2187	union xfs_btree_key *key)
2188	{
2189	union xfs_btree_key max_hkey;
2190	union xfs_btree_key hkey;
2191	union xfs_btree_rec *rec;
2192	union xfs_btree_key *high;
2193	int n;
2194
2195	rec = xfs_btree_rec_addr(cur, n: 1, block);
2196	cur->bc_ops->init_key_from_rec(key, rec);
2197
2198	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2199
2200	cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2201	for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2202	rec = xfs_btree_rec_addr(cur, n, block);
2203	cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2204	if (xfs_btree_keycmp_gt(cur, &hkey, &max_hkey))
2205	max_hkey = hkey;
2206	}
2207
2208	high = xfs_btree_high_key_from_key(cur, key);
2209	memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2210	}
2211	}
2212
2213	/* Determine the low (and high if overlapped) keys of a node block */
2214	STATIC void
2215	xfs_btree_get_node_keys(
2216	struct xfs_btree_cur *cur,
2217	struct xfs_btree_block *block,
2218	union xfs_btree_key *key)
2219	{
2220	union xfs_btree_key *hkey;
2221	union xfs_btree_key *max_hkey;
2222	union xfs_btree_key *high;
2223	int n;
2224
2225	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2226	memcpy(key, xfs_btree_key_addr(cur, n: 1, block),
2227	cur->bc_ops->key_len / 2);
2228
2229	max_hkey = xfs_btree_high_key_addr(cur, n: 1, block);
2230	for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2231	hkey = xfs_btree_high_key_addr(cur, n, block);
2232	if (xfs_btree_keycmp_gt(cur, hkey, max_hkey))
2233	max_hkey = hkey;
2234	}
2235
2236	high = xfs_btree_high_key_from_key(cur, key);
2237	memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2238	} else {
2239	memcpy(key, xfs_btree_key_addr(cur, n: 1, block),
2240	cur->bc_ops->key_len);
2241	}
2242	}
2243
2244	/* Derive the keys for any btree block. */
2245	void
2246	xfs_btree_get_keys(
2247	struct xfs_btree_cur *cur,
2248	struct xfs_btree_block *block,
2249	union xfs_btree_key *key)
2250	{
2251	if (be16_to_cpu(block->bb_level) == 0)
2252	xfs_btree_get_leaf_keys(cur, block, key);
2253	else
2254	xfs_btree_get_node_keys(cur, block, key);
2255	}
2256
2257	/*
2258	* Decide if we need to update the parent keys of a btree block. For
2259	* a standard btree this is only necessary if we're updating the first
2260	* record/key. For an overlapping btree, we must always update the
2261	* keys because the highest key can be in any of the records or keys
2262	* in the block.
2263	*/
2264	static inline bool
2265	xfs_btree_needs_key_update(
2266	struct xfs_btree_cur *cur,
2267	int ptr)
2268	{
2269	return (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) || ptr == 1;
2270	}
2271
2272	/*
2273	* Update the low and high parent keys of the given level, progressing
2274	* towards the root. If force_all is false, stop if the keys for a given
2275	* level do not need updating.
2276	*/
2277	STATIC int
2278	__xfs_btree_updkeys(
2279	struct xfs_btree_cur *cur,
2280	int level,
2281	struct xfs_btree_block *block,
2282	struct xfs_buf *bp0,
2283	bool force_all)
2284	{
2285	union xfs_btree_key key; /* keys from current level */
2286	union xfs_btree_key *lkey; /* keys from the next level up */
2287	union xfs_btree_key *hkey;
2288	union xfs_btree_key *nlkey; /* keys from the next level up */
2289	union xfs_btree_key *nhkey;
2290	struct xfs_buf *bp;
2291	int ptr;
2292
2293	ASSERT(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING);
2294
2295	/* Exit if there aren't any parent levels to update. */
2296	if (level + 1 >= cur->bc_nlevels)
2297	return 0;
2298
2299	trace_xfs_btree_updkeys(cur, level, bp0);
2300
2301	lkey = &key;
2302	hkey = xfs_btree_high_key_from_key(cur, key: lkey);
2303	xfs_btree_get_keys(cur, block, key: lkey);
2304	for (level++; level < cur->bc_nlevels; level++) {
2305	#ifdef DEBUG
2306	int error;
2307	#endif
2308	block = xfs_btree_get_block(cur, level, bpp: &bp);
2309	trace_xfs_btree_updkeys(cur, level, bp);
2310	#ifdef DEBUG
2311	error = xfs_btree_check_block(cur, block, level, bp);
2312	if (error)
2313	return error;
2314	#endif
2315	ptr = cur->bc_levels[level].ptr;
2316	nlkey = xfs_btree_key_addr(cur, n: ptr, block);
2317	nhkey = xfs_btree_high_key_addr(cur, n: ptr, block);
2318	if (!force_all &&
2319	xfs_btree_keycmp_eq(cur, nlkey, lkey) &&
2320	xfs_btree_keycmp_eq(cur, nhkey, hkey))
2321	break;
2322	xfs_btree_copy_keys(cur, dst_key: nlkey, src_key: lkey, numkeys: 1);
2323	xfs_btree_log_keys(cur, bp, ptr, ptr);
2324	if (level + 1 >= cur->bc_nlevels)
2325	break;
2326	xfs_btree_get_node_keys(cur, block, lkey);
2327	}
2328
2329	return 0;
2330	}
2331
2332	/* Update all the keys from some level in cursor back to the root. */
2333	STATIC int
2334	xfs_btree_updkeys_force(
2335	struct xfs_btree_cur *cur,
2336	int level)
2337	{
2338	struct xfs_buf *bp;
2339	struct xfs_btree_block *block;
2340
2341	block = xfs_btree_get_block(cur, level, bpp: &bp);
2342	return __xfs_btree_updkeys(cur, level, block, bp, true);
2343	}
2344
2345	/*
2346	* Update the parent keys of the given level, progressing towards the root.
2347	*/
2348	STATIC int
2349	xfs_btree_update_keys(
2350	struct xfs_btree_cur *cur,
2351	int level)
2352	{
2353	struct xfs_btree_block *block;
2354	struct xfs_buf *bp;
2355	union xfs_btree_key *kp;
2356	union xfs_btree_key key;
2357	int ptr;
2358
2359	ASSERT(level >= 0);
2360
2361	block = xfs_btree_get_block(cur, level, bpp: &bp);
2362	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING)
2363	return __xfs_btree_updkeys(cur, level, block, bp, false);
2364
2365	/*
2366	* Go up the tree from this level toward the root.
2367	* At each level, update the key value to the value input.
2368	* Stop when we reach a level where the cursor isn't pointing
2369	* at the first entry in the block.
2370	*/
2371	xfs_btree_get_keys(cur, block, key: &key);
2372	for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2373	#ifdef DEBUG
2374	int error;
2375	#endif
2376	block = xfs_btree_get_block(cur, level, bpp: &bp);
2377	#ifdef DEBUG
2378	error = xfs_btree_check_block(cur, block, level, bp);
2379	if (error)
2380	return error;
2381	#endif
2382	ptr = cur->bc_levels[level].ptr;
2383	kp = xfs_btree_key_addr(cur, n: ptr, block);
2384	xfs_btree_copy_keys(cur, dst_key: kp, src_key: &key, numkeys: 1);
2385	xfs_btree_log_keys(cur, bp, ptr, ptr);
2386	}
2387
2388	return 0;
2389	}
2390
2391	/*
2392	* Update the record referred to by cur to the value in the
2393	* given record. This either works (return 0) or gets an
2394	* EFSCORRUPTED error.
2395	*/
2396	int
2397	xfs_btree_update(
2398	struct xfs_btree_cur *cur,
2399	union xfs_btree_rec *rec)
2400	{
2401	struct xfs_btree_block *block;
2402	struct xfs_buf *bp;
2403	int error;
2404	int ptr;
2405	union xfs_btree_rec *rp;
2406
2407	/* Pick up the current block. */
2408	block = xfs_btree_get_block(cur, level: 0, bpp: &bp);
2409
2410	#ifdef DEBUG
2411	error = xfs_btree_check_block(cur, block, 0, bp);
2412	if (error)
2413	goto error0;
2414	#endif
2415	/* Get the address of the rec to be updated. */
2416	ptr = cur->bc_levels[0].ptr;
2417	rp = xfs_btree_rec_addr(cur, n: ptr, block);
2418
2419	/* Fill in the new contents and log them. */
2420	xfs_btree_copy_recs(cur, rp, rec, 1);
2421	xfs_btree_log_recs(cur, bp, first: ptr, last: ptr);
2422
2423	/*
2424	* If we are tracking the last record in the tree and
2425	* we are at the far right edge of the tree, update it.
2426	*/
2427	if (xfs_btree_is_lastrec(cur, block, 0)) {
2428	cur->bc_ops->update_lastrec(cur, block, rec,
2429	ptr, LASTREC_UPDATE);
2430	}
2431
2432	/* Pass new key value up to our parent. */
2433	if (xfs_btree_needs_key_update(cur, ptr)) {
2434	error = xfs_btree_update_keys(cur, 0);
2435	if (error)
2436	goto error0;
2437	}
2438
2439	return 0;
2440
2441	error0:
2442	return error;
2443	}
2444
2445	/*
2446	* Move 1 record left from cur/level if possible.
2447	* Update cur to reflect the new path.
2448	*/
2449	STATIC int /* error */
2450	xfs_btree_lshift(
2451	struct xfs_btree_cur *cur,
2452	int level,
2453	int *stat) /* success/failure */
2454	{
2455	struct xfs_buf *lbp; /* left buffer pointer */
2456	struct xfs_btree_block *left; /* left btree block */
2457	int lrecs; /* left record count */
2458	struct xfs_buf *rbp; /* right buffer pointer */
2459	struct xfs_btree_block *right; /* right btree block */
2460	struct xfs_btree_cur *tcur; /* temporary btree cursor */
2461	int rrecs; /* right record count */
2462	union xfs_btree_ptr lptr; /* left btree pointer */
2463	union xfs_btree_key *rkp = NULL; /* right btree key */
2464	union xfs_btree_ptr *rpp = NULL; /* right address pointer */
2465	union xfs_btree_rec *rrp = NULL; /* right record pointer */
2466	int error; /* error return value */
2467	int i;
2468
2469	if (xfs_btree_at_iroot(cur, level))
2470	goto out0;
2471
2472	/* Set up variables for this block as "right". */
2473	right = xfs_btree_get_block(cur, level, bpp: &rbp);
2474
2475	#ifdef DEBUG
2476	error = xfs_btree_check_block(cur, right, level, rbp);
2477	if (error)
2478	goto error0;
2479	#endif
2480
2481	/* If we've got no left sibling then we can't shift an entry left. */
2482	xfs_btree_get_sibling(cur, block: right, ptr: &lptr, XFS_BB_LEFTSIB);
2483	if (xfs_btree_ptr_is_null(cur, &lptr))
2484	goto out0;
2485
2486	/*
2487	* If the cursor entry is the one that would be moved, don't
2488	* do it... it's too complicated.
2489	*/
2490	if (cur->bc_levels[level].ptr <= 1)
2491	goto out0;
2492
2493	/* Set up the left neighbor as "left". */
2494	error = xfs_btree_read_buf_block(cur, ptr: &lptr, flags: 0, block: &left, bpp: &lbp);
2495	if (error)
2496	goto error0;
2497
2498	/* If it's full, it can't take another entry. */
2499	lrecs = xfs_btree_get_numrecs(block: left);
2500	if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2501	goto out0;
2502
2503	rrecs = xfs_btree_get_numrecs(block: right);
2504
2505	/*
2506	* We add one entry to the left side and remove one for the right side.
2507	* Account for it here, the changes will be updated on disk and logged
2508	* later.
2509	*/
2510	lrecs++;
2511	rrecs--;
2512
2513	XFS_BTREE_STATS_INC(cur, lshift);
2514	XFS_BTREE_STATS_ADD(cur, moves, 1);
2515
2516	/*
2517	* If non-leaf, copy a key and a ptr to the left block.
2518	* Log the changes to the left block.
2519	*/
2520	if (level > 0) {
2521	/* It's a non-leaf. Move keys and pointers. */
2522	union xfs_btree_key *lkp; /* left btree key */
2523	union xfs_btree_ptr *lpp; /* left address pointer */
2524
2525	lkp = xfs_btree_key_addr(cur, n: lrecs, block: left);
2526	rkp = xfs_btree_key_addr(cur, n: 1, block: right);
2527
2528	lpp = xfs_btree_ptr_addr(cur, n: lrecs, block: left);
2529	rpp = xfs_btree_ptr_addr(cur, n: 1, block: right);
2530
2531	error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2532	if (error)
2533	goto error0;
2534
2535	xfs_btree_copy_keys(cur, dst_key: lkp, src_key: rkp, numkeys: 1);
2536	xfs_btree_copy_ptrs(cur, dst_ptr: lpp, src_ptr: rpp, numptrs: 1);
2537
2538	xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2539	xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2540
2541	ASSERT(cur->bc_ops->keys_inorder(cur,
2542	xfs_btree_key_addr(cur, n: lrecs - 1, block: left), lkp));
2543	} else {
2544	/* It's a leaf. Move records. */
2545	union xfs_btree_rec *lrp; /* left record pointer */
2546
2547	lrp = xfs_btree_rec_addr(cur, n: lrecs, block: left);
2548	rrp = xfs_btree_rec_addr(cur, n: 1, block: right);
2549
2550	xfs_btree_copy_recs(cur, lrp, rrp, 1);
2551	xfs_btree_log_recs(cur, bp: lbp, first: lrecs, last: lrecs);
2552
2553	ASSERT(cur->bc_ops->recs_inorder(cur,
2554	xfs_btree_rec_addr(cur, n: lrecs - 1, block: left), lrp));
2555	}
2556
2557	xfs_btree_set_numrecs(left, lrecs);
2558	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2559
2560	xfs_btree_set_numrecs(right, rrecs);
2561	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2562
2563	/*
2564	* Slide the contents of right down one entry.
2565	*/
2566	XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2567	if (level > 0) {
2568	/* It's a nonleaf. operate on keys and ptrs */
2569	for (i = 0; i < rrecs; i++) {
2570	error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2571	if (error)
2572	goto error0;
2573	}
2574
2575	xfs_btree_shift_keys(cur,
2576	xfs_btree_key_addr(cur, n: 2, block: right),
2577	-1, rrecs);
2578	xfs_btree_shift_ptrs(cur,
2579	xfs_btree_ptr_addr(cur, n: 2, block: right),
2580	-1, rrecs);
2581
2582	xfs_btree_log_keys(cur, rbp, 1, rrecs);
2583	xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2584	} else {
2585	/* It's a leaf. operate on records */
2586	xfs_btree_shift_recs(cur,
2587	xfs_btree_rec_addr(cur, n: 2, block: right),
2588	-1, rrecs);
2589	xfs_btree_log_recs(cur, bp: rbp, first: 1, last: rrecs);
2590	}
2591
2592	/*
2593	* Using a temporary cursor, update the parent key values of the
2594	* block on the left.
2595	*/
2596	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2597	error = xfs_btree_dup_cursor(cur, ncur: &tcur);
2598	if (error)
2599	goto error0;
2600	i = xfs_btree_firstrec(tcur, level);
2601	if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2602	xfs_btree_mark_sick(cur);
2603	error = -EFSCORRUPTED;
2604	goto error0;
2605	}
2606
2607	error = xfs_btree_decrement(cur: tcur, level, stat: &i);
2608	if (error)
2609	goto error1;
2610
2611	/* Update the parent high keys of the left block, if needed. */
2612	error = xfs_btree_update_keys(tcur, level);
2613	if (error)
2614	goto error1;
2615
2616	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_NOERROR);
2617	}
2618
2619	/* Update the parent keys of the right block. */
2620	error = xfs_btree_update_keys(cur, level);
2621	if (error)
2622	goto error0;
2623
2624	/* Slide the cursor value left one. */
2625	cur->bc_levels[level].ptr--;
2626
2627	*stat = 1;
2628	return 0;
2629
2630	out0:
2631	*stat = 0;
2632	return 0;
2633
2634	error0:
2635	return error;
2636
2637	error1:
2638	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_ERROR);
2639	return error;
2640	}
2641
2642	/*
2643	* Move 1 record right from cur/level if possible.
2644	* Update cur to reflect the new path.
2645	*/
2646	STATIC int /* error */
2647	xfs_btree_rshift(
2648	struct xfs_btree_cur *cur,
2649	int level,
2650	int *stat) /* success/failure */
2651	{
2652	struct xfs_buf *lbp; /* left buffer pointer */
2653	struct xfs_btree_block *left; /* left btree block */
2654	struct xfs_buf *rbp; /* right buffer pointer */
2655	struct xfs_btree_block *right; /* right btree block */
2656	struct xfs_btree_cur *tcur; /* temporary btree cursor */
2657	union xfs_btree_ptr rptr; /* right block pointer */
2658	union xfs_btree_key *rkp; /* right btree key */
2659	int rrecs; /* right record count */
2660	int lrecs; /* left record count */
2661	int error; /* error return value */
2662	int i; /* loop counter */
2663
2664	if (xfs_btree_at_iroot(cur, level))
2665	goto out0;
2666
2667	/* Set up variables for this block as "left". */
2668	left = xfs_btree_get_block(cur, level, bpp: &lbp);
2669
2670	#ifdef DEBUG
2671	error = xfs_btree_check_block(cur, left, level, lbp);
2672	if (error)
2673	goto error0;
2674	#endif
2675
2676	/* If we've got no right sibling then we can't shift an entry right. */
2677	xfs_btree_get_sibling(cur, block: left, ptr: &rptr, XFS_BB_RIGHTSIB);
2678	if (xfs_btree_ptr_is_null(cur, &rptr))
2679	goto out0;
2680
2681	/*
2682	* If the cursor entry is the one that would be moved, don't
2683	* do it... it's too complicated.
2684	*/
2685	lrecs = xfs_btree_get_numrecs(block: left);
2686	if (cur->bc_levels[level].ptr >= lrecs)
2687	goto out0;
2688
2689	/* Set up the right neighbor as "right". */
2690	error = xfs_btree_read_buf_block(cur, ptr: &rptr, flags: 0, block: &right, bpp: &rbp);
2691	if (error)
2692	goto error0;
2693
2694	/* If it's full, it can't take another entry. */
2695	rrecs = xfs_btree_get_numrecs(block: right);
2696	if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2697	goto out0;
2698
2699	XFS_BTREE_STATS_INC(cur, rshift);
2700	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2701
2702	/*
2703	* Make a hole at the start of the right neighbor block, then
2704	* copy the last left block entry to the hole.
2705	*/
2706	if (level > 0) {
2707	/* It's a nonleaf. make a hole in the keys and ptrs */
2708	union xfs_btree_key *lkp;
2709	union xfs_btree_ptr *lpp;
2710	union xfs_btree_ptr *rpp;
2711
2712	lkp = xfs_btree_key_addr(cur, n: lrecs, block: left);
2713	lpp = xfs_btree_ptr_addr(cur, n: lrecs, block: left);
2714	rkp = xfs_btree_key_addr(cur, n: 1, block: right);
2715	rpp = xfs_btree_ptr_addr(cur, n: 1, block: right);
2716
2717	for (i = rrecs - 1; i >= 0; i--) {
2718	error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2719	if (error)
2720	goto error0;
2721	}
2722
2723	xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2724	xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2725
2726	error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2727	if (error)
2728	goto error0;
2729
2730	/* Now put the new data in, and log it. */
2731	xfs_btree_copy_keys(cur, dst_key: rkp, src_key: lkp, numkeys: 1);
2732	xfs_btree_copy_ptrs(cur, dst_ptr: rpp, src_ptr: lpp, numptrs: 1);
2733
2734	xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2735	xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2736
2737	ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2738	xfs_btree_key_addr(cur, n: 2, block: right)));
2739	} else {
2740	/* It's a leaf. make a hole in the records */
2741	union xfs_btree_rec *lrp;
2742	union xfs_btree_rec *rrp;
2743
2744	lrp = xfs_btree_rec_addr(cur, n: lrecs, block: left);
2745	rrp = xfs_btree_rec_addr(cur, n: 1, block: right);
2746
2747	xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2748
2749	/* Now put the new data in, and log it. */
2750	xfs_btree_copy_recs(cur, rrp, lrp, 1);
2751	xfs_btree_log_recs(cur, bp: rbp, first: 1, last: rrecs + 1);
2752	}
2753
2754	/*
2755	* Decrement and log left's numrecs, bump and log right's numrecs.
2756	*/
2757	xfs_btree_set_numrecs(left, --lrecs);
2758	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2759
2760	xfs_btree_set_numrecs(right, ++rrecs);
2761	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2762
2763	/*
2764	* Using a temporary cursor, update the parent key values of the
2765	* block on the right.
2766	*/
2767	error = xfs_btree_dup_cursor(cur, ncur: &tcur);
2768	if (error)
2769	goto error0;
2770	i = xfs_btree_lastrec(tcur, level);
2771	if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2772	xfs_btree_mark_sick(cur);
2773	error = -EFSCORRUPTED;
2774	goto error0;
2775	}
2776
2777	error = xfs_btree_increment(cur: tcur, level, stat: &i);
2778	if (error)
2779	goto error1;
2780
2781	/* Update the parent high keys of the left block, if needed. */
2782	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2783	error = xfs_btree_update_keys(cur, level);
2784	if (error)
2785	goto error1;
2786	}
2787
2788	/* Update the parent keys of the right block. */
2789	error = xfs_btree_update_keys(tcur, level);
2790	if (error)
2791	goto error1;
2792
2793	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_NOERROR);
2794
2795	*stat = 1;
2796	return 0;
2797
2798	out0:
2799	*stat = 0;
2800	return 0;
2801
2802	error0:
2803	return error;
2804
2805	error1:
2806	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_ERROR);
2807	return error;
2808	}
2809
2810	static inline int
2811	xfs_btree_alloc_block(
2812	struct xfs_btree_cur *cur,
2813	const union xfs_btree_ptr *hint_block,
2814	union xfs_btree_ptr *new_block,
2815	int *stat)
2816	{
2817	int error;
2818
2819	/*
2820	* Don't allow block allocation for a staging cursor, because staging
2821	* cursors do not support regular btree modifications.
2822	*
2823	* Bulk loading uses a separate callback to obtain new blocks from a
2824	* preallocated list, which prevents ENOSPC failures during loading.
2825	*/
2826	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
2827	ASSERT(0);
2828	return -EFSCORRUPTED;
2829	}
2830
2831	error = cur->bc_ops->alloc_block(cur, hint_block, new_block, stat);
2832	trace_xfs_btree_alloc_block(cur, new_block, *stat, error);
2833	return error;
2834	}
2835
2836	/*
2837	* Split cur/level block in half.
2838	* Return new block number and the key to its first
2839	* record (to be inserted into parent).
2840	*/
2841	STATIC int /* error */
2842	__xfs_btree_split(
2843	struct xfs_btree_cur *cur,
2844	int level,
2845	union xfs_btree_ptr *ptrp,
2846	union xfs_btree_key *key,
2847	struct xfs_btree_cur **curp,
2848	int *stat) /* success/failure */
2849	{
2850	union xfs_btree_ptr lptr; /* left sibling block ptr */
2851	struct xfs_buf *lbp; /* left buffer pointer */
2852	struct xfs_btree_block *left; /* left btree block */
2853	union xfs_btree_ptr rptr; /* right sibling block ptr */
2854	struct xfs_buf *rbp; /* right buffer pointer */
2855	struct xfs_btree_block *right; /* right btree block */
2856	union xfs_btree_ptr rrptr; /* right-right sibling ptr */
2857	struct xfs_buf *rrbp; /* right-right buffer pointer */
2858	struct xfs_btree_block *rrblock; /* right-right btree block */
2859	int lrecs;
2860	int rrecs;
2861	int src_index;
2862	int error; /* error return value */
2863	int i;
2864
2865	XFS_BTREE_STATS_INC(cur, split);
2866
2867	/* Set up left block (current one). */
2868	left = xfs_btree_get_block(cur, level, bpp: &lbp);
2869
2870	#ifdef DEBUG
2871	error = xfs_btree_check_block(cur, left, level, lbp);
2872	if (error)
2873	goto error0;
2874	#endif
2875
2876	xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2877
2878	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2879	error = xfs_btree_alloc_block(cur, hint_block: &lptr, new_block: &rptr, stat);
2880	if (error)
2881	goto error0;
2882	if (*stat == 0)
2883	goto out0;
2884	XFS_BTREE_STATS_INC(cur, alloc);
2885
2886	/* Set up the new block as "right". */
2887	error = xfs_btree_get_buf_block(cur, ptr: &rptr, block: &right, bpp: &rbp);
2888	if (error)
2889	goto error0;
2890
2891	/* Fill in the btree header for the new right block. */
2892	xfs_btree_init_block_cur(cur, bp: rbp, level: xfs_btree_get_level(block: left), numrecs: 0);
2893
2894	/*
2895	* Split the entries between the old and the new block evenly.
2896	* Make sure that if there's an odd number of entries now, that
2897	* each new block will have the same number of entries.
2898	*/
2899	lrecs = xfs_btree_get_numrecs(block: left);
2900	rrecs = lrecs / 2;
2901	if ((lrecs & 1) && cur->bc_levels[level].ptr <= rrecs + 1)
2902	rrecs++;
2903	src_index = (lrecs - rrecs + 1);
2904
2905	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2906
2907	/* Adjust numrecs for the later get_*_keys() calls. */
2908	lrecs -= rrecs;
2909	xfs_btree_set_numrecs(left, lrecs);
2910	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(block: right) + rrecs);
2911
2912	/*
2913	* Copy btree block entries from the left block over to the
2914	* new block, the right. Update the right block and log the
2915	* changes.
2916	*/
2917	if (level > 0) {
2918	/* It's a non-leaf. Move keys and pointers. */
2919	union xfs_btree_key *lkp; /* left btree key */
2920	union xfs_btree_ptr *lpp; /* left address pointer */
2921	union xfs_btree_key *rkp; /* right btree key */
2922	union xfs_btree_ptr *rpp; /* right address pointer */
2923
2924	lkp = xfs_btree_key_addr(cur, n: src_index, block: left);
2925	lpp = xfs_btree_ptr_addr(cur, n: src_index, block: left);
2926	rkp = xfs_btree_key_addr(cur, n: 1, block: right);
2927	rpp = xfs_btree_ptr_addr(cur, n: 1, block: right);
2928
2929	for (i = src_index; i < rrecs; i++) {
2930	error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2931	if (error)
2932	goto error0;
2933	}
2934
2935	/* Copy the keys & pointers to the new block. */
2936	xfs_btree_copy_keys(cur, dst_key: rkp, src_key: lkp, numkeys: rrecs);
2937	xfs_btree_copy_ptrs(cur, dst_ptr: rpp, src_ptr: lpp, numptrs: rrecs);
2938
2939	xfs_btree_log_keys(cur, rbp, 1, rrecs);
2940	xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2941
2942	/* Stash the keys of the new block for later insertion. */
2943	xfs_btree_get_node_keys(cur, right, key);
2944	} else {
2945	/* It's a leaf. Move records. */
2946	union xfs_btree_rec *lrp; /* left record pointer */
2947	union xfs_btree_rec *rrp; /* right record pointer */
2948
2949	lrp = xfs_btree_rec_addr(cur, n: src_index, block: left);
2950	rrp = xfs_btree_rec_addr(cur, n: 1, block: right);
2951
2952	/* Copy records to the new block. */
2953	xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2954	xfs_btree_log_recs(cur, bp: rbp, first: 1, last: rrecs);
2955
2956	/* Stash the keys of the new block for later insertion. */
2957	xfs_btree_get_leaf_keys(cur, right, key);
2958	}
2959
2960	/*
2961	* Find the left block number by looking in the buffer.
2962	* Adjust sibling pointers.
2963	*/
2964	xfs_btree_get_sibling(cur, block: left, ptr: &rrptr, XFS_BB_RIGHTSIB);
2965	xfs_btree_set_sibling(cur, block: right, ptr: &rrptr, XFS_BB_RIGHTSIB);
2966	xfs_btree_set_sibling(cur, block: right, ptr: &lptr, XFS_BB_LEFTSIB);
2967	xfs_btree_set_sibling(cur, block: left, ptr: &rptr, XFS_BB_RIGHTSIB);
2968
2969	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2970	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2971
2972	/*
2973	* If there's a block to the new block's right, make that block
2974	* point back to right instead of to left.
2975	*/
2976	if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2977	error = xfs_btree_read_buf_block(cur, ptr: &rrptr,
2978	flags: 0, block: &rrblock, bpp: &rrbp);
2979	if (error)
2980	goto error0;
2981	xfs_btree_set_sibling(cur, block: rrblock, ptr: &rptr, XFS_BB_LEFTSIB);
2982	xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2983	}
2984
2985	/* Update the parent high keys of the left block, if needed. */
2986	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2987	error = xfs_btree_update_keys(cur, level);
2988	if (error)
2989	goto error0;
2990	}
2991
2992	/*
2993	* If the cursor is really in the right block, move it there.
2994	* If it's just pointing past the last entry in left, then we'll
2995	* insert there, so don't change anything in that case.
2996	*/
2997	if (cur->bc_levels[level].ptr > lrecs + 1) {
2998	xfs_btree_setbuf(cur, level, rbp);
2999	cur->bc_levels[level].ptr -= lrecs;
3000	}
3001	/*
3002	* If there are more levels, we'll need another cursor which refers
3003	* the right block, no matter where this cursor was.
3004	*/
3005	if (level + 1 < cur->bc_nlevels) {
3006	error = xfs_btree_dup_cursor(cur, ncur: curp);
3007	if (error)
3008	goto error0;
3009	(*curp)->bc_levels[level + 1].ptr++;
3010	}
3011	*ptrp = rptr;
3012	*stat = 1;
3013	return 0;
3014	out0:
3015	*stat = 0;
3016	return 0;
3017
3018	error0:
3019	return error;
3020	}
3021
3022	#ifdef __KERNEL__
3023	struct xfs_btree_split_args {
3024	struct xfs_btree_cur *cur;
3025	int level;
3026	union xfs_btree_ptr *ptrp;
3027	union xfs_btree_key *key;
3028	struct xfs_btree_cur **curp;
3029	int *stat; /* success/failure */
3030	int result;
3031	bool kswapd; /* allocation in kswapd context */
3032	struct completion *done;
3033	struct work_struct work;
3034	};
3035
3036	/*
3037	* Stack switching interfaces for allocation
3038	*/
3039	static void
3040	xfs_btree_split_worker(
3041	struct work_struct *work)
3042	{
3043	struct xfs_btree_split_args *args = container_of(work,
3044	struct xfs_btree_split_args, work);
3045	unsigned long pflags;
3046	unsigned long new_pflags = 0;
3047
3048	/*
3049	* we are in a transaction context here, but may also be doing work
3050	* in kswapd context, and hence we may need to inherit that state
3051	* temporarily to ensure that we don't block waiting for memory reclaim
3052	* in any way.
3053	*/
3054	if (args->kswapd)
3055	new_pflags |= PF_MEMALLOC | PF_KSWAPD;
3056
3057	current_set_flags_nested(&pflags, new_pflags);
3058	xfs_trans_set_context(args->cur->bc_tp);
3059
3060	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
3061	args->key, args->curp, args->stat);
3062
3063	xfs_trans_clear_context(args->cur->bc_tp);
3064	current_restore_flags_nested(&pflags, new_pflags);
3065
3066	/*
3067	* Do not access args after complete() has run here. We don't own args
3068	* and the owner may run and free args before we return here.
3069	*/
3070	complete(args->done);
3071
3072	}
3073
3074	/*
3075	* BMBT split requests often come in with little stack to work on so we push
3076	* them off to a worker thread so there is lots of stack to use. For the other
3077	* btree types, just call directly to avoid the context switch overhead here.
3078	*
3079	* Care must be taken here - the work queue rescuer thread introduces potential
3080	* AGF <> worker queue deadlocks if the BMBT block allocation has to lock new
3081	* AGFs to allocate blocks. A task being run by the rescuer could attempt to
3082	* lock an AGF that is already locked by a task queued to run by the rescuer,
3083	* resulting in an ABBA deadlock as the rescuer cannot run the lock holder to
3084	* release it until the current thread it is running gains the lock.
3085	*
3086	* To avoid this issue, we only ever queue BMBT splits that don't have an AGF
3087	* already locked to allocate from. The only place that doesn't hold an AGF
3088	* locked is unwritten extent conversion at IO completion, but that has already
3089	* been offloaded to a worker thread and hence has no stack consumption issues
3090	* we have to worry about.
3091	*/
3092	STATIC int /* error */
3093	xfs_btree_split(
3094	struct xfs_btree_cur *cur,
3095	int level,
3096	union xfs_btree_ptr *ptrp,
3097	union xfs_btree_key *key,
3098	struct xfs_btree_cur **curp,
3099	int *stat) /* success/failure */
3100	{
3101	struct xfs_btree_split_args args;
3102	DECLARE_COMPLETION_ONSTACK(done);
3103
3104	if (!xfs_btree_is_bmap(cur->bc_ops) ||
3105	cur->bc_tp->t_highest_agno == NULLAGNUMBER)
3106	return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
3107
3108	args.cur = cur;
3109	args.level = level;
3110	args.ptrp = ptrp;
3111	args.key = key;
3112	args.curp = curp;
3113	args.stat = stat;
3114	args.done = &done;
3115	args.kswapd = current_is_kswapd();
3116	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
3117	queue_work(xfs_alloc_wq, &args.work);
3118	wait_for_completion(&done);
3119	destroy_work_on_stack(&args.work);
3120	return args.result;
3121	}
3122	#else
3123	#define xfs_btree_split __xfs_btree_split
3124	#endif /* __KERNEL__ */
3125
3126	/*
3127	* Copy the old inode root contents into a real block and make the
3128	* broot point to it.
3129	*/
3130	int /* error */
3131	xfs_btree_new_iroot(
3132	struct xfs_btree_cur *cur, /* btree cursor */
3133	int *logflags, /* logging flags for inode */
3134	int *stat) /* return status - 0 fail */
3135	{
3136	struct xfs_buf *cbp; /* buffer for cblock */
3137	struct xfs_btree_block *block; /* btree block */
3138	struct xfs_btree_block *cblock; /* child btree block */
3139	union xfs_btree_key *ckp; /* child key pointer */
3140	union xfs_btree_ptr *cpp; /* child ptr pointer */
3141	union xfs_btree_key *kp; /* pointer to btree key */
3142	union xfs_btree_ptr *pp; /* pointer to block addr */
3143	union xfs_btree_ptr nptr; /* new block addr */
3144	int level; /* btree level */
3145	int error; /* error return code */
3146	int i; /* loop counter */
3147
3148	XFS_BTREE_STATS_INC(cur, newroot);
3149
3150	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
3151
3152	level = cur->bc_nlevels - 1;
3153
3154	block = xfs_btree_get_iroot(cur);
3155	pp = xfs_btree_ptr_addr(cur, n: 1, block);
3156
3157	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3158	error = xfs_btree_alloc_block(cur, hint_block: pp, new_block: &nptr, stat);
3159	if (error)
3160	goto error0;
3161	if (*stat == 0)
3162	return 0;
3163
3164	XFS_BTREE_STATS_INC(cur, alloc);
3165
3166	/* Copy the root into a real block. */
3167	error = xfs_btree_get_buf_block(cur, ptr: &nptr, block: &cblock, bpp: &cbp);
3168	if (error)
3169	goto error0;
3170
3171	/*
3172	* we can't just memcpy() the root in for CRC enabled btree blocks.
3173	* In that case have to also ensure the blkno remains correct
3174	*/
3175	memcpy(cblock, block, xfs_btree_block_len(cur));
3176	if (xfs_has_crc(cur->bc_mp)) {
3177	__be64 bno = cpu_to_be64(xfs_buf_daddr(cbp));
3178	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
3179	cblock->bb_u.l.bb_blkno = bno;
3180	else
3181	cblock->bb_u.s.bb_blkno = bno;
3182	}
3183
3184	be16_add_cpu(&block->bb_level, 1);
3185	xfs_btree_set_numrecs(block, 1);
3186	cur->bc_nlevels++;
3187	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3188	cur->bc_levels[level + 1].ptr = 1;
3189
3190	kp = xfs_btree_key_addr(cur, n: 1, block);
3191	ckp = xfs_btree_key_addr(cur, n: 1, block: cblock);
3192	xfs_btree_copy_keys(cur, dst_key: ckp, src_key: kp, numkeys: xfs_btree_get_numrecs(block: cblock));
3193
3194	cpp = xfs_btree_ptr_addr(cur, n: 1, block: cblock);
3195	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
3196	error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3197	if (error)
3198	goto error0;
3199	}
3200
3201	xfs_btree_copy_ptrs(cur, dst_ptr: cpp, src_ptr: pp, numptrs: xfs_btree_get_numrecs(block: cblock));
3202
3203	error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
3204	if (error)
3205	goto error0;
3206
3207	xfs_btree_copy_ptrs(cur, dst_ptr: pp, src_ptr: &nptr, numptrs: 1);
3208
3209	xfs_iroot_realloc(cur->bc_ino.ip,
3210	1 - xfs_btree_get_numrecs(block: cblock),
3211	cur->bc_ino.whichfork);
3212
3213	xfs_btree_setbuf(cur, level, cbp);
3214
3215	/*
3216	* Do all this logging at the end so that
3217	* the root is at the right level.
3218	*/
3219	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3220	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3221	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3222
3223	*logflags |=
3224	XFS_ILOG_CORE | xfs_ilog_fbroot(w: cur->bc_ino.whichfork);
3225	*stat = 1;
3226	return 0;
3227	error0:
3228	return error;
3229	}
3230
3231	static void
3232	xfs_btree_set_root(
3233	struct xfs_btree_cur *cur,
3234	const union xfs_btree_ptr *ptr,
3235	int inc)
3236	{
3237	if (cur->bc_flags & XFS_BTREE_STAGING) {
3238	/* Update the btree root information for a per-AG fake root. */
3239	cur->bc_ag.afake->af_root = be32_to_cpu(ptr->s);
3240	cur->bc_ag.afake->af_levels += inc;
3241	} else {
3242	cur->bc_ops->set_root(cur, ptr, inc);
3243	}
3244	}
3245
3246	/*
3247	* Allocate a new root block, fill it in.
3248	*/
3249	STATIC int /* error */
3250	xfs_btree_new_root(
3251	struct xfs_btree_cur *cur, /* btree cursor */
3252	int *stat) /* success/failure */
3253	{
3254	struct xfs_btree_block *block; /* one half of the old root block */
3255	struct xfs_buf *bp; /* buffer containing block */
3256	int error; /* error return value */
3257	struct xfs_buf *lbp; /* left buffer pointer */
3258	struct xfs_btree_block *left; /* left btree block */
3259	struct xfs_buf *nbp; /* new (root) buffer */
3260	struct xfs_btree_block *new; /* new (root) btree block */
3261	int nptr; /* new value for key index, 1 or 2 */
3262	struct xfs_buf *rbp; /* right buffer pointer */
3263	struct xfs_btree_block *right; /* right btree block */
3264	union xfs_btree_ptr rptr;
3265	union xfs_btree_ptr lptr;
3266
3267	XFS_BTREE_STATS_INC(cur, newroot);
3268
3269	/* initialise our start point from the cursor */
3270	xfs_btree_init_ptr_from_cur(cur, ptr: &rptr);
3271
3272	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3273	error = xfs_btree_alloc_block(cur, hint_block: &rptr, new_block: &lptr, stat);
3274	if (error)
3275	goto error0;
3276	if (*stat == 0)
3277	goto out0;
3278	XFS_BTREE_STATS_INC(cur, alloc);
3279
3280	/* Set up the new block. */
3281	error = xfs_btree_get_buf_block(cur, ptr: &lptr, block: &new, bpp: &nbp);
3282	if (error)
3283	goto error0;
3284
3285	/* Set the root in the holding structure increasing the level by 1. */
3286	xfs_btree_set_root(cur, ptr: &lptr, inc: 1);
3287
3288	/*
3289	* At the previous root level there are now two blocks: the old root,
3290	* and the new block generated when it was split. We don't know which
3291	* one the cursor is pointing at, so we set up variables "left" and
3292	* "right" for each case.
3293	*/
3294	block = xfs_btree_get_block(cur, level: cur->bc_nlevels - 1, bpp: &bp);
3295
3296	#ifdef DEBUG
3297	error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3298	if (error)
3299	goto error0;
3300	#endif
3301
3302	xfs_btree_get_sibling(cur, block, ptr: &rptr, XFS_BB_RIGHTSIB);
3303	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3304	/* Our block is left, pick up the right block. */
3305	lbp = bp;
3306	xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3307	left = block;
3308	error = xfs_btree_read_buf_block(cur, ptr: &rptr, flags: 0, block: &right, bpp: &rbp);
3309	if (error)
3310	goto error0;
3311	bp = rbp;
3312	nptr = 1;
3313	} else {
3314	/* Our block is right, pick up the left block. */
3315	rbp = bp;
3316	xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3317	right = block;
3318	xfs_btree_get_sibling(cur, block: right, ptr: &lptr, XFS_BB_LEFTSIB);
3319	error = xfs_btree_read_buf_block(cur, ptr: &lptr, flags: 0, block: &left, bpp: &lbp);
3320	if (error)
3321	goto error0;
3322	bp = lbp;
3323	nptr = 2;
3324	}
3325
3326	/* Fill in the new block's btree header and log it. */
3327	xfs_btree_init_block_cur(cur, bp: nbp, level: cur->bc_nlevels, numrecs: 2);
3328	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3329	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3330	!xfs_btree_ptr_is_null(cur, &rptr));
3331
3332	/* Fill in the key data in the new root. */
3333	if (xfs_btree_get_level(block: left) > 0) {
3334	/*
3335	* Get the keys for the left block's keys and put them directly
3336	* in the parent block. Do the same for the right block.
3337	*/
3338	xfs_btree_get_node_keys(cur, left,
3339	xfs_btree_key_addr(cur, n: 1, block: new));
3340	xfs_btree_get_node_keys(cur, right,
3341	xfs_btree_key_addr(cur, n: 2, block: new));
3342	} else {
3343	/*
3344	* Get the keys for the left block's records and put them
3345	* directly in the parent block. Do the same for the right
3346	* block.
3347	*/
3348	xfs_btree_get_leaf_keys(cur, left,
3349	xfs_btree_key_addr(cur, n: 1, block: new));
3350	xfs_btree_get_leaf_keys(cur, right,
3351	xfs_btree_key_addr(cur, n: 2, block: new));
3352	}
3353	xfs_btree_log_keys(cur, nbp, 1, 2);
3354
3355	/* Fill in the pointer data in the new root. */
3356	xfs_btree_copy_ptrs(cur,
3357	dst_ptr: xfs_btree_ptr_addr(cur, n: 1, block: new), src_ptr: &lptr, numptrs: 1);
3358	xfs_btree_copy_ptrs(cur,
3359	dst_ptr: xfs_btree_ptr_addr(cur, n: 2, block: new), src_ptr: &rptr, numptrs: 1);
3360	xfs_btree_log_ptrs(cur, nbp, 1, 2);
3361
3362	/* Fix up the cursor. */
3363	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3364	cur->bc_levels[cur->bc_nlevels].ptr = nptr;
3365	cur->bc_nlevels++;
3366	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3367	*stat = 1;
3368	return 0;
3369	error0:
3370	return error;
3371	out0:
3372	*stat = 0;
3373	return 0;
3374	}
3375
3376	STATIC int
3377	xfs_btree_make_block_unfull(
3378	struct xfs_btree_cur *cur, /* btree cursor */
3379	int level, /* btree level */
3380	int numrecs,/* # of recs in block */
3381	int *oindex,/* old tree index */
3382	int *index, /* new tree index */
3383	union xfs_btree_ptr *nptr, /* new btree ptr */
3384	struct xfs_btree_cur **ncur, /* new btree cursor */
3385	union xfs_btree_key *key, /* key of new block */
3386	int *stat)
3387	{
3388	int error = 0;
3389
3390	if (xfs_btree_at_iroot(cur, level)) {
3391	struct xfs_inode *ip = cur->bc_ino.ip;
3392
3393	if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3394	/* A root block that can be made bigger. */
3395	xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3396	*stat = 1;
3397	} else {
3398	/* A root block that needs replacing */
3399	int logflags = 0;
3400
3401	error = xfs_btree_new_iroot(cur, logflags: &logflags, stat);
3402	if (error || *stat == 0)
3403	return error;
3404
3405	xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3406	}
3407
3408	return 0;
3409	}
3410
3411	/* First, try shifting an entry to the right neighbor. */
3412	error = xfs_btree_rshift(cur, level, stat);
3413	if (error || *stat)
3414	return error;
3415
3416	/* Next, try shifting an entry to the left neighbor. */
3417	error = xfs_btree_lshift(cur, level, stat);
3418	if (error)
3419	return error;
3420
3421	if (*stat) {
3422	*oindex = *index = cur->bc_levels[level].ptr;
3423	return 0;
3424	}
3425
3426	/*
3427	* Next, try splitting the current block in half.
3428	*
3429	* If this works we have to re-set our variables because we
3430	* could be in a different block now.
3431	*/
3432	error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3433	if (error || *stat == 0)
3434	return error;
3435
3436
3437	*index = cur->bc_levels[level].ptr;
3438	return 0;
3439	}
3440
3441	/*
3442	* Insert one record/level. Return information to the caller
3443	* allowing the next level up to proceed if necessary.
3444	*/
3445	STATIC int
3446	xfs_btree_insrec(
3447	struct xfs_btree_cur *cur, /* btree cursor */
3448	int level, /* level to insert record at */
3449	union xfs_btree_ptr *ptrp, /* i/o: block number inserted */
3450	union xfs_btree_rec *rec, /* record to insert */
3451	union xfs_btree_key *key, /* i/o: block key for ptrp */
3452	struct xfs_btree_cur **curp, /* output: new cursor replacing cur */
3453	int *stat) /* success/failure */
3454	{
3455	struct xfs_btree_block *block; /* btree block */
3456	struct xfs_buf *bp; /* buffer for block */
3457	union xfs_btree_ptr nptr; /* new block ptr */
3458	struct xfs_btree_cur *ncur = NULL; /* new btree cursor */
3459	union xfs_btree_key nkey; /* new block key */
3460	union xfs_btree_key *lkey;
3461	int optr; /* old key/record index */
3462	int ptr; /* key/record index */
3463	int numrecs;/* number of records */
3464	int error; /* error return value */
3465	int i;
3466	xfs_daddr_t old_bn;
3467
3468	ncur = NULL;
3469	lkey = &nkey;
3470
3471	/*
3472	* If we have an external root pointer, and we've made it to the
3473	* root level, allocate a new root block and we're done.
3474	*/
3475	if (cur->bc_ops->type != XFS_BTREE_TYPE_INODE &&
3476	level >= cur->bc_nlevels) {
3477	error = xfs_btree_new_root(cur, stat);
3478	xfs_btree_set_ptr_null(cur, ptr: ptrp);
3479
3480	return error;
3481	}
3482
3483	/* If we're off the left edge, return failure. */
3484	ptr = cur->bc_levels[level].ptr;
3485	if (ptr == 0) {
3486	*stat = 0;
3487	return 0;
3488	}
3489
3490	optr = ptr;
3491
3492	XFS_BTREE_STATS_INC(cur, insrec);
3493
3494	/* Get pointers to the btree buffer and block. */
3495	block = xfs_btree_get_block(cur, level, bpp: &bp);
3496	old_bn = bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL;
3497	numrecs = xfs_btree_get_numrecs(block);
3498
3499	#ifdef DEBUG
3500	error = xfs_btree_check_block(cur, block, level, bp);
3501	if (error)
3502	goto error0;
3503
3504	/* Check that the new entry is being inserted in the right place. */
3505	if (ptr <= numrecs) {
3506	if (level == 0) {
3507	ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3508	xfs_btree_rec_addr(cur, ptr, block)));
3509	} else {
3510	ASSERT(cur->bc_ops->keys_inorder(cur, key,
3511	xfs_btree_key_addr(cur, ptr, block)));
3512	}
3513	}
3514	#endif
3515
3516	/*
3517	* If the block is full, we can't insert the new entry until we
3518	* make the block un-full.
3519	*/
3520	xfs_btree_set_ptr_null(cur, ptr: &nptr);
3521	if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3522	error = xfs_btree_make_block_unfull(cur, level, numrecs,
3523	&optr, &ptr, &nptr, &ncur, lkey, stat);
3524	if (error || *stat == 0)
3525	goto error0;
3526	}
3527
3528	/*
3529	* The current block may have changed if the block was
3530	* previously full and we have just made space in it.
3531	*/
3532	block = xfs_btree_get_block(cur, level, bpp: &bp);
3533	numrecs = xfs_btree_get_numrecs(block);
3534
3535	#ifdef DEBUG
3536	error = xfs_btree_check_block(cur, block, level, bp);
3537	if (error)
3538	goto error0;
3539	#endif
3540
3541	/*
3542	* At this point we know there's room for our new entry in the block
3543	* we're pointing at.
3544	*/
3545	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3546
3547	if (level > 0) {
3548	/* It's a nonleaf. make a hole in the keys and ptrs */
3549	union xfs_btree_key *kp;
3550	union xfs_btree_ptr *pp;
3551
3552	kp = xfs_btree_key_addr(cur, n: ptr, block);
3553	pp = xfs_btree_ptr_addr(cur, n: ptr, block);
3554
3555	for (i = numrecs - ptr; i >= 0; i--) {
3556	error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3557	if (error)
3558	goto error0;
3559	}
3560
3561	xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3562	xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3563
3564	error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3565	if (error)
3566	goto error0;
3567
3568	/* Now put the new data in, bump numrecs and log it. */
3569	xfs_btree_copy_keys(cur, dst_key: kp, src_key: key, numkeys: 1);
3570	xfs_btree_copy_ptrs(cur, dst_ptr: pp, src_ptr: ptrp, numptrs: 1);
3571	numrecs++;
3572	xfs_btree_set_numrecs(block, numrecs);
3573	xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3574	xfs_btree_log_keys(cur, bp, ptr, numrecs);
3575	#ifdef DEBUG
3576	if (ptr < numrecs) {
3577	ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3578	xfs_btree_key_addr(cur, ptr + 1, block)));
3579	}
3580	#endif
3581	} else {
3582	/* It's a leaf. make a hole in the records */
3583	union xfs_btree_rec *rp;
3584
3585	rp = xfs_btree_rec_addr(cur, n: ptr, block);
3586
3587	xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3588
3589	/* Now put the new data in, bump numrecs and log it. */
3590	xfs_btree_copy_recs(cur, rp, rec, 1);
3591	xfs_btree_set_numrecs(block, ++numrecs);
3592	xfs_btree_log_recs(cur, bp, first: ptr, last: numrecs);
3593	#ifdef DEBUG
3594	if (ptr < numrecs) {
3595	ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3596	xfs_btree_rec_addr(cur, ptr + 1, block)));
3597	}
3598	#endif
3599	}
3600
3601	/* Log the new number of records in the btree header. */
3602	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3603
3604	/*
3605	* If we just inserted into a new tree block, we have to
3606	* recalculate nkey here because nkey is out of date.
3607	*
3608	* Otherwise we're just updating an existing block (having shoved
3609	* some records into the new tree block), so use the regular key
3610	* update mechanism.
3611	*/
3612	if (bp && xfs_buf_daddr(bp) != old_bn) {
3613	xfs_btree_get_keys(cur, block, key: lkey);
3614	} else if (xfs_btree_needs_key_update(cur, optr)) {
3615	error = xfs_btree_update_keys(cur, level);
3616	if (error)
3617	goto error0;
3618	}
3619
3620	/*
3621	* If we are tracking the last record in the tree and
3622	* we are at the far right edge of the tree, update it.
3623	*/
3624	if (xfs_btree_is_lastrec(cur, block, level)) {
3625	cur->bc_ops->update_lastrec(cur, block, rec,
3626	ptr, LASTREC_INSREC);
3627	}
3628
3629	/*
3630	* Return the new block number, if any.
3631	* If there is one, give back a record value and a cursor too.
3632	*/
3633	*ptrp = nptr;
3634	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3635	xfs_btree_copy_keys(cur, dst_key: key, src_key: lkey, numkeys: 1);
3636	*curp = ncur;
3637	}
3638
3639	*stat = 1;
3640	return 0;
3641
3642	error0:
3643	if (ncur)
3644	xfs_btree_del_cursor(cur: ncur, error);
3645	return error;
3646	}
3647
3648	/*
3649	* Insert the record at the point referenced by cur.
3650	*
3651	* A multi-level split of the tree on insert will invalidate the original
3652	* cursor. All callers of this function should assume that the cursor is
3653	* no longer valid and revalidate it.
3654	*/
3655	int
3656	xfs_btree_insert(
3657	struct xfs_btree_cur *cur,
3658	int *stat)
3659	{
3660	int error; /* error return value */
3661	int i; /* result value, 0 for failure */
3662	int level; /* current level number in btree */
3663	union xfs_btree_ptr nptr; /* new block number (split result) */
3664	struct xfs_btree_cur *ncur; /* new cursor (split result) */
3665	struct xfs_btree_cur *pcur; /* previous level's cursor */
3666	union xfs_btree_key bkey; /* key of block to insert */
3667	union xfs_btree_key *key;
3668	union xfs_btree_rec rec; /* record to insert */
3669
3670	level = 0;
3671	ncur = NULL;
3672	pcur = cur;
3673	key = &bkey;
3674
3675	xfs_btree_set_ptr_null(cur, ptr: &nptr);
3676
3677	/* Make a key out of the record data to be inserted, and save it. */
3678	cur->bc_ops->init_rec_from_cur(cur, &rec);
3679	cur->bc_ops->init_key_from_rec(key, &rec);
3680
3681	/*
3682	* Loop going up the tree, starting at the leaf level.
3683	* Stop when we don't get a split block, that must mean that
3684	* the insert is finished with this level.
3685	*/
3686	do {
3687	/*
3688	* Insert nrec/nptr into this level of the tree.
3689	* Note if we fail, nptr will be null.
3690	*/
3691	error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3692	&ncur, &i);
3693	if (error) {
3694	if (pcur != cur)
3695	xfs_btree_del_cursor(cur: pcur, XFS_BTREE_ERROR);
3696	goto error0;
3697	}
3698
3699	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3700	xfs_btree_mark_sick(cur);
3701	error = -EFSCORRUPTED;
3702	goto error0;
3703	}
3704	level++;
3705
3706	/*
3707	* See if the cursor we just used is trash.
3708	* Can't trash the caller's cursor, but otherwise we should
3709	* if ncur is a new cursor or we're about to be done.
3710	*/
3711	if (pcur != cur &&
3712	(ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3713	/* Save the state from the cursor before we trash it */
3714	if (cur->bc_ops->update_cursor &&
3715	!(cur->bc_flags & XFS_BTREE_STAGING))
3716	cur->bc_ops->update_cursor(pcur, cur);
3717	cur->bc_nlevels = pcur->bc_nlevels;
3718	xfs_btree_del_cursor(cur: pcur, XFS_BTREE_NOERROR);
3719	}
3720	/* If we got a new cursor, switch to it. */
3721	if (ncur) {
3722	pcur = ncur;
3723	ncur = NULL;
3724	}
3725	} while (!xfs_btree_ptr_is_null(cur, &nptr));
3726
3727	*stat = i;
3728	return 0;
3729	error0:
3730	return error;
3731	}
3732
3733	/*
3734	* Try to merge a non-leaf block back into the inode root.
3735	*
3736	* Note: the killroot names comes from the fact that we're effectively
3737	* killing the old root block. But because we can't just delete the
3738	* inode we have to copy the single block it was pointing to into the
3739	* inode.
3740	*/
3741	STATIC int
3742	xfs_btree_kill_iroot(
3743	struct xfs_btree_cur *cur)
3744	{
3745	int whichfork = cur->bc_ino.whichfork;
3746	struct xfs_inode *ip = cur->bc_ino.ip;
3747	struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
3748	struct xfs_btree_block *block;
3749	struct xfs_btree_block *cblock;
3750	union xfs_btree_key *kp;
3751	union xfs_btree_key *ckp;
3752	union xfs_btree_ptr *pp;
3753	union xfs_btree_ptr *cpp;
3754	struct xfs_buf *cbp;
3755	int level;
3756	int index;
3757	int numrecs;
3758	int error;
3759	#ifdef DEBUG
3760	union xfs_btree_ptr ptr;
3761	#endif
3762	int i;
3763
3764	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
3765	ASSERT(cur->bc_nlevels > 1);
3766
3767	/*
3768	* Don't deal with the root block needs to be a leaf case.
3769	* We're just going to turn the thing back into extents anyway.
3770	*/
3771	level = cur->bc_nlevels - 1;
3772	if (level == 1)
3773	goto out0;
3774
3775	/*
3776	* Give up if the root has multiple children.
3777	*/
3778	block = xfs_btree_get_iroot(cur);
3779	if (xfs_btree_get_numrecs(block) != 1)
3780	goto out0;
3781
3782	cblock = xfs_btree_get_block(cur, level: level - 1, bpp: &cbp);
3783	numrecs = xfs_btree_get_numrecs(block: cblock);
3784
3785	/*
3786	* Only do this if the next level will fit.
3787	* Then the data must be copied up to the inode,
3788	* instead of freeing the root you free the next level.
3789	*/
3790	if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3791	goto out0;
3792
3793	XFS_BTREE_STATS_INC(cur, killroot);
3794
3795	#ifdef DEBUG
3796	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3797	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3798	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3799	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3800	#endif
3801
3802	index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3803	if (index) {
3804	xfs_iroot_realloc(cur->bc_ino.ip, index,
3805	cur->bc_ino.whichfork);
3806	block = ifp->if_broot;
3807	}
3808
3809	be16_add_cpu(&block->bb_numrecs, index);
3810	ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3811
3812	kp = xfs_btree_key_addr(cur, n: 1, block);
3813	ckp = xfs_btree_key_addr(cur, n: 1, block: cblock);
3814	xfs_btree_copy_keys(cur, dst_key: kp, src_key: ckp, numkeys: numrecs);
3815
3816	pp = xfs_btree_ptr_addr(cur, n: 1, block);
3817	cpp = xfs_btree_ptr_addr(cur, n: 1, block: cblock);
3818
3819	for (i = 0; i < numrecs; i++) {
3820	error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3821	if (error)
3822	return error;
3823	}
3824
3825	xfs_btree_copy_ptrs(cur, dst_ptr: pp, src_ptr: cpp, numptrs: numrecs);
3826
3827	error = xfs_btree_free_block(cur, bp: cbp);
3828	if (error)
3829	return error;
3830
3831	cur->bc_levels[level - 1].bp = NULL;
3832	be16_add_cpu(&block->bb_level, -1);
3833	xfs_trans_log_inode(cur->bc_tp, ip,
3834	XFS_ILOG_CORE | xfs_ilog_fbroot(w: cur->bc_ino.whichfork));
3835	cur->bc_nlevels--;
3836	out0:
3837	return 0;
3838	}
3839
3840	/*
3841	* Kill the current root node, and replace it with it's only child node.
3842	*/
3843	STATIC int
3844	xfs_btree_kill_root(
3845	struct xfs_btree_cur *cur,
3846	struct xfs_buf *bp,
3847	int level,
3848	union xfs_btree_ptr *newroot)
3849	{
3850	int error;
3851
3852	XFS_BTREE_STATS_INC(cur, killroot);
3853
3854	/*
3855	* Update the root pointer, decreasing the level by 1 and then
3856	* free the old root.
3857	*/
3858	xfs_btree_set_root(cur, ptr: newroot, inc: -1);
3859
3860	error = xfs_btree_free_block(cur, bp);
3861	if (error)
3862	return error;
3863
3864	cur->bc_levels[level].bp = NULL;
3865	cur->bc_levels[level].ra = 0;
3866	cur->bc_nlevels--;
3867
3868	return 0;
3869	}
3870
3871	STATIC int
3872	xfs_btree_dec_cursor(
3873	struct xfs_btree_cur *cur,
3874	int level,
3875	int *stat)
3876	{
3877	int error;
3878	int i;
3879
3880	if (level > 0) {
3881	error = xfs_btree_decrement(cur, level, stat: &i);
3882	if (error)
3883	return error;
3884	}
3885
3886	*stat = 1;
3887	return 0;
3888	}
3889
3890	/*
3891	* Single level of the btree record deletion routine.
3892	* Delete record pointed to by cur/level.
3893	* Remove the record from its block then rebalance the tree.
3894	* Return 0 for error, 1 for done, 2 to go on to the next level.
3895	*/
3896	STATIC int /* error */
3897	xfs_btree_delrec(
3898	struct xfs_btree_cur *cur, /* btree cursor */
3899	int level, /* level removing record from */
3900	int *stat) /* fail/done/go-on */
3901	{
3902	struct xfs_btree_block *block; /* btree block */
3903	union xfs_btree_ptr cptr; /* current block ptr */
3904	struct xfs_buf *bp; /* buffer for block */
3905	int error; /* error return value */
3906	int i; /* loop counter */
3907	union xfs_btree_ptr lptr; /* left sibling block ptr */
3908	struct xfs_buf *lbp; /* left buffer pointer */
3909	struct xfs_btree_block *left; /* left btree block */
3910	int lrecs = 0; /* left record count */
3911	int ptr; /* key/record index */
3912	union xfs_btree_ptr rptr; /* right sibling block ptr */
3913	struct xfs_buf *rbp; /* right buffer pointer */
3914	struct xfs_btree_block *right; /* right btree block */
3915	struct xfs_btree_block *rrblock; /* right-right btree block */
3916	struct xfs_buf *rrbp; /* right-right buffer pointer */
3917	int rrecs = 0; /* right record count */
3918	struct xfs_btree_cur *tcur; /* temporary btree cursor */
3919	int numrecs; /* temporary numrec count */
3920
3921	tcur = NULL;
3922
3923	/* Get the index of the entry being deleted, check for nothing there. */
3924	ptr = cur->bc_levels[level].ptr;
3925	if (ptr == 0) {
3926	*stat = 0;
3927	return 0;
3928	}
3929
3930	/* Get the buffer & block containing the record or key/ptr. */
3931	block = xfs_btree_get_block(cur, level, bpp: &bp);
3932	numrecs = xfs_btree_get_numrecs(block);
3933
3934	#ifdef DEBUG
3935	error = xfs_btree_check_block(cur, block, level, bp);
3936	if (error)
3937	goto error0;
3938	#endif
3939
3940	/* Fail if we're off the end of the block. */
3941	if (ptr > numrecs) {
3942	*stat = 0;
3943	return 0;
3944	}
3945
3946	XFS_BTREE_STATS_INC(cur, delrec);
3947	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3948
3949	/* Excise the entries being deleted. */
3950	if (level > 0) {
3951	/* It's a nonleaf. operate on keys and ptrs */
3952	union xfs_btree_key *lkp;
3953	union xfs_btree_ptr *lpp;
3954
3955	lkp = xfs_btree_key_addr(cur, n: ptr + 1, block);
3956	lpp = xfs_btree_ptr_addr(cur, n: ptr + 1, block);
3957
3958	for (i = 0; i < numrecs - ptr; i++) {
3959	error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3960	if (error)
3961	goto error0;
3962	}
3963
3964	if (ptr < numrecs) {
3965	xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3966	xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3967	xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3968	xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3969	}
3970	} else {
3971	/* It's a leaf. operate on records */
3972	if (ptr < numrecs) {
3973	xfs_btree_shift_recs(cur,
3974	xfs_btree_rec_addr(cur, n: ptr + 1, block),
3975	-1, numrecs - ptr);
3976	xfs_btree_log_recs(cur, bp, first: ptr, last: numrecs - 1);
3977	}
3978	}
3979
3980	/*
3981	* Decrement and log the number of entries in the block.
3982	*/
3983	xfs_btree_set_numrecs(block, --numrecs);
3984	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3985
3986	/*
3987	* If we are tracking the last record in the tree and
3988	* we are at the far right edge of the tree, update it.
3989	*/
3990	if (xfs_btree_is_lastrec(cur, block, level)) {
3991	cur->bc_ops->update_lastrec(cur, block, NULL,
3992	ptr, LASTREC_DELREC);
3993	}
3994
3995	/*
3996	* We're at the root level. First, shrink the root block in-memory.
3997	* Try to get rid of the next level down. If we can't then there's
3998	* nothing left to do.
3999	*/
4000	if (xfs_btree_at_iroot(cur, level)) {
4001	xfs_iroot_realloc(cur->bc_ino.ip, -1, cur->bc_ino.whichfork);
4002
4003	error = xfs_btree_kill_iroot(cur);
4004	if (error)
4005	goto error0;
4006
4007	error = xfs_btree_dec_cursor(cur, level, stat);
4008	if (error)
4009	goto error0;
4010	*stat = 1;
4011	return 0;
4012	}
4013
4014	/*
4015	* If this is the root level, and there's only one entry left, and it's
4016	* NOT the leaf level, then we can get rid of this level.
4017	*/
4018	if (level == cur->bc_nlevels - 1) {
4019	if (numrecs == 1 && level > 0) {
4020	union xfs_btree_ptr *pp;
4021	/*
4022	* pp is still set to the first pointer in the block.
4023	* Make it the new root of the btree.
4024	*/
4025	pp = xfs_btree_ptr_addr(cur, n: 1, block);
4026	error = xfs_btree_kill_root(cur, bp, level, pp);
4027	if (error)
4028	goto error0;
4029	} else if (level > 0) {
4030	error = xfs_btree_dec_cursor(cur, level, stat);
4031	if (error)
4032	goto error0;
4033	}
4034	*stat = 1;
4035	return 0;
4036	}
4037
4038	/*
4039	* If we deleted the leftmost entry in the block, update the
4040	* key values above us in the tree.
4041	*/
4042	if (xfs_btree_needs_key_update(cur, ptr)) {
4043	error = xfs_btree_update_keys(cur, level);
4044	if (error)
4045	goto error0;
4046	}
4047
4048	/*
4049	* If the number of records remaining in the block is at least
4050	* the minimum, we're done.
4051	*/
4052	if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
4053	error = xfs_btree_dec_cursor(cur, level, stat);
4054	if (error)
4055	goto error0;
4056	return 0;
4057	}
4058
4059	/*
4060	* Otherwise, we have to move some records around to keep the
4061	* tree balanced. Look at the left and right sibling blocks to
4062	* see if we can re-balance by moving only one record.
4063	*/
4064	xfs_btree_get_sibling(cur, block, ptr: &rptr, XFS_BB_RIGHTSIB);
4065	xfs_btree_get_sibling(cur, block, ptr: &lptr, XFS_BB_LEFTSIB);
4066
4067	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE) {
4068	/*
4069	* One child of root, need to get a chance to copy its contents
4070	* into the root and delete it. Can't go up to next level,
4071	* there's nothing to delete there.
4072	*/
4073	if (xfs_btree_ptr_is_null(cur, &rptr) &&
4074	xfs_btree_ptr_is_null(cur, &lptr) &&
4075	level == cur->bc_nlevels - 2) {
4076	error = xfs_btree_kill_iroot(cur);
4077	if (!error)
4078	error = xfs_btree_dec_cursor(cur, level, stat);
4079	if (error)
4080	goto error0;
4081	return 0;
4082	}
4083	}
4084
4085	ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
4086	!xfs_btree_ptr_is_null(cur, &lptr));
4087
4088	/*
4089	* Duplicate the cursor so our btree manipulations here won't
4090	* disrupt the next level up.
4091	*/
4092	error = xfs_btree_dup_cursor(cur, ncur: &tcur);
4093	if (error)
4094	goto error0;
4095
4096	/*
4097	* If there's a right sibling, see if it's ok to shift an entry
4098	* out of it.
4099	*/
4100	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
4101	/*
4102	* Move the temp cursor to the last entry in the next block.
4103	* Actually any entry but the first would suffice.
4104	*/
4105	i = xfs_btree_lastrec(tcur, level);
4106	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4107	xfs_btree_mark_sick(cur);
4108	error = -EFSCORRUPTED;
4109	goto error0;
4110	}
4111
4112	error = xfs_btree_increment(cur: tcur, level, stat: &i);
4113	if (error)
4114	goto error0;
4115	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4116	xfs_btree_mark_sick(cur);
4117	error = -EFSCORRUPTED;
4118	goto error0;
4119	}
4120
4121	i = xfs_btree_lastrec(tcur, level);
4122	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4123	xfs_btree_mark_sick(cur);
4124	error = -EFSCORRUPTED;
4125	goto error0;
4126	}
4127
4128	/* Grab a pointer to the block. */
4129	right = xfs_btree_get_block(cur: tcur, level, bpp: &rbp);
4130	#ifdef DEBUG
4131	error = xfs_btree_check_block(tcur, right, level, rbp);
4132	if (error)
4133	goto error0;
4134	#endif
4135	/* Grab the current block number, for future use. */
4136	xfs_btree_get_sibling(cur: tcur, block: right, ptr: &cptr, XFS_BB_LEFTSIB);
4137
4138	/*
4139	* If right block is full enough so that removing one entry
4140	* won't make it too empty, and left-shifting an entry out
4141	* of right to us works, we're done.
4142	*/
4143	if (xfs_btree_get_numrecs(block: right) - 1 >=
4144	cur->bc_ops->get_minrecs(tcur, level)) {
4145	error = xfs_btree_lshift(tcur, level, &i);
4146	if (error)
4147	goto error0;
4148	if (i) {
4149	ASSERT(xfs_btree_get_numrecs(block) >=
4150	cur->bc_ops->get_minrecs(tcur, level));
4151
4152	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_NOERROR);
4153	tcur = NULL;
4154
4155	error = xfs_btree_dec_cursor(cur, level, stat);
4156	if (error)
4157	goto error0;
4158	return 0;
4159	}
4160	}
4161
4162	/*
4163	* Otherwise, grab the number of records in right for
4164	* future reference, and fix up the temp cursor to point
4165	* to our block again (last record).
4166	*/
4167	rrecs = xfs_btree_get_numrecs(block: right);
4168	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4169	i = xfs_btree_firstrec(tcur, level);
4170	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4171	xfs_btree_mark_sick(cur);
4172	error = -EFSCORRUPTED;
4173	goto error0;
4174	}
4175
4176	error = xfs_btree_decrement(cur: tcur, level, stat: &i);
4177	if (error)
4178	goto error0;
4179	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4180	xfs_btree_mark_sick(cur);
4181	error = -EFSCORRUPTED;
4182	goto error0;
4183	}
4184	}
4185	}
4186
4187	/*
4188	* If there's a left sibling, see if it's ok to shift an entry
4189	* out of it.
4190	*/
4191	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4192	/*
4193	* Move the temp cursor to the first entry in the
4194	* previous block.
4195	*/
4196	i = xfs_btree_firstrec(tcur, level);
4197	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4198	xfs_btree_mark_sick(cur);
4199	error = -EFSCORRUPTED;
4200	goto error0;
4201	}
4202
4203	error = xfs_btree_decrement(cur: tcur, level, stat: &i);
4204	if (error)
4205	goto error0;
4206	i = xfs_btree_firstrec(tcur, level);
4207	if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4208	xfs_btree_mark_sick(cur);
4209	error = -EFSCORRUPTED;
4210	goto error0;
4211	}
4212
4213	/* Grab a pointer to the block. */
4214	left = xfs_btree_get_block(cur: tcur, level, bpp: &lbp);
4215	#ifdef DEBUG
4216	error = xfs_btree_check_block(cur, left, level, lbp);
4217	if (error)
4218	goto error0;
4219	#endif
4220	/* Grab the current block number, for future use. */
4221	xfs_btree_get_sibling(cur: tcur, block: left, ptr: &cptr, XFS_BB_RIGHTSIB);
4222
4223	/*
4224	* If left block is full enough so that removing one entry
4225	* won't make it too empty, and right-shifting an entry out
4226	* of left to us works, we're done.
4227	*/
4228	if (xfs_btree_get_numrecs(block: left) - 1 >=
4229	cur->bc_ops->get_minrecs(tcur, level)) {
4230	error = xfs_btree_rshift(tcur, level, &i);
4231	if (error)
4232	goto error0;
4233	if (i) {
4234	ASSERT(xfs_btree_get_numrecs(block) >=
4235	cur->bc_ops->get_minrecs(tcur, level));
4236	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_NOERROR);
4237	tcur = NULL;
4238	if (level == 0)
4239	cur->bc_levels[0].ptr++;
4240
4241	*stat = 1;
4242	return 0;
4243	}
4244	}
4245
4246	/*
4247	* Otherwise, grab the number of records in right for
4248	* future reference.
4249	*/
4250	lrecs = xfs_btree_get_numrecs(block: left);
4251	}
4252
4253	/* Delete the temp cursor, we're done with it. */
4254	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_NOERROR);
4255	tcur = NULL;
4256
4257	/* If here, we need to do a join to keep the tree balanced. */
4258	ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4259
4260	if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4261	lrecs + xfs_btree_get_numrecs(block) <=
4262	cur->bc_ops->get_maxrecs(cur, level)) {
4263	/*
4264	* Set "right" to be the starting block,
4265	* "left" to be the left neighbor.
4266	*/
4267	rptr = cptr;
4268	right = block;
4269	rbp = bp;
4270	error = xfs_btree_read_buf_block(cur, ptr: &lptr, flags: 0, block: &left, bpp: &lbp);
4271	if (error)
4272	goto error0;
4273
4274	/*
4275	* If that won't work, see if we can join with the right neighbor block.
4276	*/
4277	} else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4278	rrecs + xfs_btree_get_numrecs(block) <=
4279	cur->bc_ops->get_maxrecs(cur, level)) {
4280	/*
4281	* Set "left" to be the starting block,
4282	* "right" to be the right neighbor.
4283	*/
4284	lptr = cptr;
4285	left = block;
4286	lbp = bp;
4287	error = xfs_btree_read_buf_block(cur, ptr: &rptr, flags: 0, block: &right, bpp: &rbp);
4288	if (error)
4289	goto error0;
4290
4291	/*
4292	* Otherwise, we can't fix the imbalance.
4293	* Just return. This is probably a logic error, but it's not fatal.
4294	*/
4295	} else {
4296	error = xfs_btree_dec_cursor(cur, level, stat);
4297	if (error)
4298	goto error0;
4299	return 0;
4300	}
4301
4302	rrecs = xfs_btree_get_numrecs(block: right);
4303	lrecs = xfs_btree_get_numrecs(block: left);
4304
4305	/*
4306	* We're now going to join "left" and "right" by moving all the stuff
4307	* in "right" to "left" and deleting "right".
4308	*/
4309	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4310	if (level > 0) {
4311	/* It's a non-leaf. Move keys and pointers. */
4312	union xfs_btree_key *lkp; /* left btree key */
4313	union xfs_btree_ptr *lpp; /* left address pointer */
4314	union xfs_btree_key *rkp; /* right btree key */
4315	union xfs_btree_ptr *rpp; /* right address pointer */
4316
4317	lkp = xfs_btree_key_addr(cur, n: lrecs + 1, block: left);
4318	lpp = xfs_btree_ptr_addr(cur, n: lrecs + 1, block: left);
4319	rkp = xfs_btree_key_addr(cur, n: 1, block: right);
4320	rpp = xfs_btree_ptr_addr(cur, n: 1, block: right);
4321
4322	for (i = 1; i < rrecs; i++) {
4323	error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4324	if (error)
4325	goto error0;
4326	}
4327
4328	xfs_btree_copy_keys(cur, dst_key: lkp, src_key: rkp, numkeys: rrecs);
4329	xfs_btree_copy_ptrs(cur, dst_ptr: lpp, src_ptr: rpp, numptrs: rrecs);
4330
4331	xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4332	xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4333	} else {
4334	/* It's a leaf. Move records. */
4335	union xfs_btree_rec *lrp; /* left record pointer */
4336	union xfs_btree_rec *rrp; /* right record pointer */
4337
4338	lrp = xfs_btree_rec_addr(cur, n: lrecs + 1, block: left);
4339	rrp = xfs_btree_rec_addr(cur, n: 1, block: right);
4340
4341	xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4342	xfs_btree_log_recs(cur, bp: lbp, first: lrecs + 1, last: lrecs + rrecs);
4343	}
4344
4345	XFS_BTREE_STATS_INC(cur, join);
4346
4347	/*
4348	* Fix up the number of records and right block pointer in the
4349	* surviving block, and log it.
4350	*/
4351	xfs_btree_set_numrecs(left, lrecs + rrecs);
4352	xfs_btree_get_sibling(cur, block: right, ptr: &cptr, XFS_BB_RIGHTSIB);
4353	xfs_btree_set_sibling(cur, block: left, ptr: &cptr, XFS_BB_RIGHTSIB);
4354	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4355
4356	/* If there is a right sibling, point it to the remaining block. */
4357	xfs_btree_get_sibling(cur, block: left, ptr: &cptr, XFS_BB_RIGHTSIB);
4358	if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4359	error = xfs_btree_read_buf_block(cur, ptr: &cptr, flags: 0, block: &rrblock, bpp: &rrbp);
4360	if (error)
4361	goto error0;
4362	xfs_btree_set_sibling(cur, block: rrblock, ptr: &lptr, XFS_BB_LEFTSIB);
4363	xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4364	}
4365
4366	/* Free the deleted block. */
4367	error = xfs_btree_free_block(cur, bp: rbp);
4368	if (error)
4369	goto error0;
4370
4371	/*
4372	* If we joined with the left neighbor, set the buffer in the
4373	* cursor to the left block, and fix up the index.
4374	*/
4375	if (bp != lbp) {
4376	cur->bc_levels[level].bp = lbp;
4377	cur->bc_levels[level].ptr += lrecs;
4378	cur->bc_levels[level].ra = 0;
4379	}
4380	/*
4381	* If we joined with the right neighbor and there's a level above
4382	* us, increment the cursor at that level.
4383	*/
4384	else if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE ||
4385	level + 1 < cur->bc_nlevels) {
4386	error = xfs_btree_increment(cur, level: level + 1, stat: &i);
4387	if (error)
4388	goto error0;
4389	}
4390
4391	/*
4392	* Readjust the ptr at this level if it's not a leaf, since it's
4393	* still pointing at the deletion point, which makes the cursor
4394	* inconsistent. If this makes the ptr 0, the caller fixes it up.
4395	* We can't use decrement because it would change the next level up.
4396	*/
4397	if (level > 0)
4398	cur->bc_levels[level].ptr--;
4399
4400	/*
4401	* We combined blocks, so we have to update the parent keys if the
4402	* btree supports overlapped intervals. However,
4403	* bc_levels[level + 1].ptr points to the old block so that the caller
4404	* knows which record to delete. Therefore, the caller must be savvy
4405	* enough to call updkeys for us if we return stat == 2. The other
4406	* exit points from this function don't require deletions further up
4407	* the tree, so they can call updkeys directly.
4408	*/
4409
4410	/* Return value means the next level up has something to do. */
4411	*stat = 2;
4412	return 0;
4413
4414	error0:
4415	if (tcur)
4416	xfs_btree_del_cursor(cur: tcur, XFS_BTREE_ERROR);
4417	return error;
4418	}
4419
4420	/*
4421	* Delete the record pointed to by cur.
4422	* The cursor refers to the place where the record was (could be inserted)
4423	* when the operation returns.
4424	*/
4425	int /* error */
4426	xfs_btree_delete(
4427	struct xfs_btree_cur *cur,
4428	int *stat) /* success/failure */
4429	{
4430	int error; /* error return value */
4431	int level;
4432	int i;
4433	bool joined = false;
4434
4435	/*
4436	* Go up the tree, starting at leaf level.
4437	*
4438	* If 2 is returned then a join was done; go to the next level.
4439	* Otherwise we are done.
4440	*/
4441	for (level = 0, i = 2; i == 2; level++) {
4442	error = xfs_btree_delrec(cur, level, &i);
4443	if (error)
4444	goto error0;
4445	if (i == 2)
4446	joined = true;
4447	}
4448
4449	/*
4450	* If we combined blocks as part of deleting the record, delrec won't
4451	* have updated the parent high keys so we have to do that here.
4452	*/
4453	if (joined && (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING)) {
4454	error = xfs_btree_updkeys_force(cur, 0);
4455	if (error)
4456	goto error0;
4457	}
4458
4459	if (i == 0) {
4460	for (level = 1; level < cur->bc_nlevels; level++) {
4461	if (cur->bc_levels[level].ptr == 0) {
4462	error = xfs_btree_decrement(cur, level, stat: &i);
4463	if (error)
4464	goto error0;
4465	break;
4466	}
4467	}
4468	}
4469
4470	*stat = i;
4471	return 0;
4472	error0:
4473	return error;
4474	}
4475
4476	/*
4477	* Get the data from the pointed-to record.
4478	*/
4479	int /* error */
4480	xfs_btree_get_rec(
4481	struct xfs_btree_cur *cur, /* btree cursor */
4482	union xfs_btree_rec **recp, /* output: btree record */
4483	int *stat) /* output: success/failure */
4484	{
4485	struct xfs_btree_block *block; /* btree block */
4486	struct xfs_buf *bp; /* buffer pointer */
4487	int ptr; /* record number */
4488	#ifdef DEBUG
4489	int error; /* error return value */
4490	#endif
4491
4492	ptr = cur->bc_levels[0].ptr;
4493	block = xfs_btree_get_block(cur, level: 0, bpp: &bp);
4494
4495	#ifdef DEBUG
4496	error = xfs_btree_check_block(cur, block, 0, bp);
4497	if (error)
4498	return error;
4499	#endif
4500
4501	/*
4502	* Off the right end or left end, return failure.
4503	*/
4504	if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4505	*stat = 0;
4506	return 0;
4507	}
4508
4509	/*
4510	* Point to the record and extract its data.
4511	*/
4512	*recp = xfs_btree_rec_addr(cur, n: ptr, block);
4513	*stat = 1;
4514	return 0;
4515	}
4516
4517	/* Visit a block in a btree. */
4518	STATIC int
4519	xfs_btree_visit_block(
4520	struct xfs_btree_cur *cur,
4521	int level,
4522	xfs_btree_visit_blocks_fn fn,
4523	void *data)
4524	{
4525	struct xfs_btree_block *block;
4526	struct xfs_buf *bp;
4527	union xfs_btree_ptr rptr, bufptr;
4528	int error;
4529
4530	/* do right sibling readahead */
4531	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4532	block = xfs_btree_get_block(cur, level, bpp: &bp);
4533
4534	/* process the block */
4535	error = fn(cur, level, data);
4536	if (error)
4537	return error;
4538
4539	/* now read rh sibling block for next iteration */
4540	xfs_btree_get_sibling(cur, block, ptr: &rptr, XFS_BB_RIGHTSIB);
4541	if (xfs_btree_ptr_is_null(cur, &rptr))
4542	return -ENOENT;
4543
4544	/*
4545	* We only visit blocks once in this walk, so we have to avoid the
4546	* internal xfs_btree_lookup_get_block() optimisation where it will
4547	* return the same block without checking if the right sibling points
4548	* back to us and creates a cyclic reference in the btree.
4549	*/
4550	xfs_btree_buf_to_ptr(cur, bp, &bufptr);
4551	if (xfs_btree_ptrs_equal(cur, &rptr, &bufptr)) {
4552	xfs_btree_mark_sick(cur);
4553	return -EFSCORRUPTED;
4554	}
4555
4556	return xfs_btree_lookup_get_block(cur, level, pp: &rptr, blkp: &block);
4557	}
4558
4559
4560	/* Visit every block in a btree. */
4561	int
4562	xfs_btree_visit_blocks(
4563	struct xfs_btree_cur *cur,
4564	xfs_btree_visit_blocks_fn fn,
4565	unsigned int flags,
4566	void *data)
4567	{
4568	union xfs_btree_ptr lptr;
4569	int level;
4570	struct xfs_btree_block *block = NULL;
4571	int error = 0;
4572
4573	xfs_btree_init_ptr_from_cur(cur, ptr: &lptr);
4574
4575	/* for each level */
4576	for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4577	/* grab the left hand block */
4578	error = xfs_btree_lookup_get_block(cur, level, pp: &lptr, blkp: &block);
4579	if (error)
4580	return error;
4581
4582	/* readahead the left most block for the next level down */
4583	if (level > 0) {
4584	union xfs_btree_ptr *ptr;
4585
4586	ptr = xfs_btree_ptr_addr(cur, n: 1, block);
4587	xfs_btree_readahead_ptr(cur, ptr, 1);
4588
4589	/* save for the next iteration of the loop */
4590	xfs_btree_copy_ptrs(cur, dst_ptr: &lptr, src_ptr: ptr, numptrs: 1);
4591
4592	if (!(flags & XFS_BTREE_VISIT_LEAVES))
4593	continue;
4594	} else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4595	continue;
4596	}
4597
4598	/* for each buffer in the level */
4599	do {
4600	error = xfs_btree_visit_block(cur, level, fn, data);
4601	} while (!error);
4602
4603	if (error != -ENOENT)
4604	return error;
4605	}
4606
4607	return 0;
4608	}
4609
4610	/*
4611	* Change the owner of a btree.
4612	*
4613	* The mechanism we use here is ordered buffer logging. Because we don't know
4614	* how many buffers were are going to need to modify, we don't really want to
4615	* have to make transaction reservations for the worst case of every buffer in a
4616	* full size btree as that may be more space that we can fit in the log....
4617	*
4618	* We do the btree walk in the most optimal manner possible - we have sibling
4619	* pointers so we can just walk all the blocks on each level from left to right
4620	* in a single pass, and then move to the next level and do the same. We can
4621	* also do readahead on the sibling pointers to get IO moving more quickly,
4622	* though for slow disks this is unlikely to make much difference to performance
4623	* as the amount of CPU work we have to do before moving to the next block is
4624	* relatively small.
4625	*
4626	* For each btree block that we load, modify the owner appropriately, set the
4627	* buffer as an ordered buffer and log it appropriately. We need to ensure that
4628	* we mark the region we change dirty so that if the buffer is relogged in
4629	* a subsequent transaction the changes we make here as an ordered buffer are
4630	* correctly relogged in that transaction. If we are in recovery context, then
4631	* just queue the modified buffer as delayed write buffer so the transaction
4632	* recovery completion writes the changes to disk.
4633	*/
4634	struct xfs_btree_block_change_owner_info {
4635	uint64_t new_owner;
4636	struct list_head *buffer_list;
4637	};
4638
4639	static int
4640	xfs_btree_block_change_owner(
4641	struct xfs_btree_cur *cur,
4642	int level,
4643	void *data)
4644	{
4645	struct xfs_btree_block_change_owner_info *bbcoi = data;
4646	struct xfs_btree_block *block;
4647	struct xfs_buf *bp;
4648
4649	/* modify the owner */
4650	block = xfs_btree_get_block(cur, level, bpp: &bp);
4651	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
4652	if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4653	return 0;
4654	block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4655	} else {
4656	if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4657	return 0;
4658	block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4659	}
4660
4661	/*
4662	* If the block is a root block hosted in an inode, we might not have a
4663	* buffer pointer here and we shouldn't attempt to log the change as the
4664	* information is already held in the inode and discarded when the root
4665	* block is formatted into the on-disk inode fork. We still change it,
4666	* though, so everything is consistent in memory.
4667	*/
4668	if (!bp) {
4669	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
4670	ASSERT(level == cur->bc_nlevels - 1);
4671	return 0;
4672	}
4673
4674	if (cur->bc_tp) {
4675	if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4676	xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4677	return -EAGAIN;
4678	}
4679	} else {
4680	xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4681	}
4682
4683	return 0;
4684	}
4685
4686	int
4687	xfs_btree_change_owner(
4688	struct xfs_btree_cur *cur,
4689	uint64_t new_owner,
4690	struct list_head *buffer_list)
4691	{
4692	struct xfs_btree_block_change_owner_info bbcoi;
4693
4694	bbcoi.new_owner = new_owner;
4695	bbcoi.buffer_list = buffer_list;
4696
4697	return xfs_btree_visit_blocks(cur, fn: xfs_btree_block_change_owner,
4698	XFS_BTREE_VISIT_ALL, data: &bbcoi);
4699	}
4700
4701	/* Verify the v5 fields of a long-format btree block. */
4702	xfs_failaddr_t
4703	xfs_btree_fsblock_v5hdr_verify(
4704	struct xfs_buf *bp,
4705	uint64_t owner)
4706	{
4707	struct xfs_mount *mp = bp->b_mount;
4708	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4709
4710	if (!xfs_has_crc(mp))
4711	return __this_address;
4712	if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4713	return __this_address;
4714	if (block->bb_u.l.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4715	return __this_address;
4716	if (owner != XFS_RMAP_OWN_UNKNOWN &&
4717	be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4718	return __this_address;
4719	return NULL;
4720	}
4721
4722	/* Verify a long-format btree block. */
4723	xfs_failaddr_t
4724	xfs_btree_fsblock_verify(
4725	struct xfs_buf *bp,
4726	unsigned int max_recs)
4727	{
4728	struct xfs_mount *mp = bp->b_mount;
4729	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4730	xfs_fsblock_t fsb;
4731	xfs_failaddr_t fa;
4732
4733	ASSERT(!xfs_buftarg_is_mem(bp->b_target));
4734
4735	/* numrecs verification */
4736	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4737	return __this_address;
4738
4739	/* sibling pointer verification */
4740	fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
4741	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
4742	block->bb_u.l.bb_leftsib);
4743	if (!fa)
4744	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
4745	block->bb_u.l.bb_rightsib);
4746	return fa;
4747	}
4748
4749	/* Verify an in-memory btree block. */
4750	xfs_failaddr_t
4751	xfs_btree_memblock_verify(
4752	struct xfs_buf *bp,
4753	unsigned int max_recs)
4754	{
4755	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4756	struct xfs_buftarg *btp = bp->b_target;
4757	xfs_failaddr_t fa;
4758	xfbno_t bno;
4759
4760	ASSERT(xfs_buftarg_is_mem(bp->b_target));
4761
4762	/* numrecs verification */
4763	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4764	return __this_address;
4765
4766	/* sibling pointer verification */
4767	bno = xfs_daddr_to_xfbno(xfs_buf_daddr(bp));
4768	fa = xfs_btree_check_memblock_siblings(btp, bno,
4769	block->bb_u.l.bb_leftsib);
4770	if (fa)
4771	return fa;
4772	fa = xfs_btree_check_memblock_siblings(btp, bno,
4773	block->bb_u.l.bb_rightsib);
4774	if (fa)
4775	return fa;
4776
4777	return NULL;
4778	}
4779	/**
4780	* xfs_btree_agblock_v5hdr_verify() -- verify the v5 fields of a short-format
4781	* btree block
4782	*
4783	* @bp: buffer containing the btree block
4784	*/
4785	xfs_failaddr_t
4786	xfs_btree_agblock_v5hdr_verify(
4787	struct xfs_buf *bp)
4788	{
4789	struct xfs_mount *mp = bp->b_mount;
4790	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4791	struct xfs_perag *pag = bp->b_pag;
4792
4793	if (!xfs_has_crc(mp))
4794	return __this_address;
4795	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4796	return __this_address;
4797	if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4798	return __this_address;
4799	if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4800	return __this_address;
4801	return NULL;
4802	}
4803
4804	/**
4805	* xfs_btree_agblock_verify() -- verify a short-format btree block
4806	*
4807	* @bp: buffer containing the btree block
4808	* @max_recs: maximum records allowed in this btree node
4809	*/
4810	xfs_failaddr_t
4811	xfs_btree_agblock_verify(
4812	struct xfs_buf *bp,
4813	unsigned int max_recs)
4814	{
4815	struct xfs_mount *mp = bp->b_mount;
4816	struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
4817	xfs_agblock_t agbno;
4818	xfs_failaddr_t fa;
4819
4820	ASSERT(!xfs_buftarg_is_mem(bp->b_target));
4821
4822	/* numrecs verification */
4823	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4824	return __this_address;
4825
4826	/* sibling pointer verification */
4827	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
4828	fa = xfs_btree_check_agblock_siblings(bp->b_pag, agbno,
4829	block->bb_u.s.bb_leftsib);
4830	if (!fa)
4831	fa = xfs_btree_check_agblock_siblings(bp->b_pag, agbno,
4832	block->bb_u.s.bb_rightsib);
4833	return fa;
4834	}
4835
4836	/*
4837	* For the given limits on leaf and keyptr records per block, calculate the
4838	* height of the tree needed to index the number of leaf records.
4839	*/
4840	unsigned int
4841	xfs_btree_compute_maxlevels(
4842	const unsigned int *limits,
4843	unsigned long long records)
4844	{
4845	unsigned long long level_blocks = howmany_64(records, limits[0]);
4846	unsigned int height = 1;
4847
4848	while (level_blocks > 1) {
4849	level_blocks = howmany_64(level_blocks, limits[1]);
4850	height++;
4851	}
4852
4853	return height;
4854	}
4855
4856	/*
4857	* For the given limits on leaf and keyptr records per block, calculate the
4858	* number of blocks needed to index the given number of leaf records.
4859	*/
4860	unsigned long long
4861	xfs_btree_calc_size(
4862	const unsigned int *limits,
4863	unsigned long long records)
4864	{
4865	unsigned long long level_blocks = howmany_64(records, limits[0]);
4866	unsigned long long blocks = level_blocks;
4867
4868	while (level_blocks > 1) {
4869	level_blocks = howmany_64(level_blocks, limits[1]);
4870	blocks += level_blocks;
4871	}
4872
4873	return blocks;
4874	}
4875
4876	/*
4877	* Given a number of available blocks for the btree to consume with records and
4878	* pointers, calculate the height of the tree needed to index all the records
4879	* that space can hold based on the number of pointers each interior node
4880	* holds.
4881	*
4882	* We start by assuming a single level tree consumes a single block, then track
4883	* the number of blocks each node level consumes until we no longer have space
4884	* to store the next node level. At this point, we are indexing all the leaf
4885	* blocks in the space, and there's no more free space to split the tree any
4886	* further. That's our maximum btree height.
4887	*/
4888	unsigned int
4889	xfs_btree_space_to_height(
4890	const unsigned int *limits,
4891	unsigned long long leaf_blocks)
4892	{
4893	/*
4894	* The root btree block can have fewer than minrecs pointers in it
4895	* because the tree might not be big enough to require that amount of
4896	* fanout. Hence it has a minimum size of 2 pointers, not limits[1].
4897	*/
4898	unsigned long long node_blocks = 2;
4899	unsigned long long blocks_left = leaf_blocks - 1;
4900	unsigned int height = 1;
4901
4902	if (leaf_blocks < 1)
4903	return 0;
4904
4905	while (node_blocks < blocks_left) {
4906	blocks_left -= node_blocks;
4907	node_blocks *= limits[1];
4908	height++;
4909	}
4910
4911	return height;
4912	}
4913
4914	/*
4915	* Query a regular btree for all records overlapping a given interval.
4916	* Start with a LE lookup of the key of low_rec and return all records
4917	* until we find a record with a key greater than the key of high_rec.
4918	*/
4919	STATIC int
4920	xfs_btree_simple_query_range(
4921	struct xfs_btree_cur *cur,
4922	const union xfs_btree_key *low_key,
4923	const union xfs_btree_key *high_key,
4924	xfs_btree_query_range_fn fn,
4925	void *priv)
4926	{
4927	union xfs_btree_rec *recp;
4928	union xfs_btree_key rec_key;
4929	int stat;
4930	bool firstrec = true;
4931	int error;
4932
4933	ASSERT(cur->bc_ops->init_high_key_from_rec);
4934	ASSERT(cur->bc_ops->diff_two_keys);
4935
4936	/*
4937	* Find the leftmost record. The btree cursor must be set
4938	* to the low record used to generate low_key.
4939	*/
4940	stat = 0;
4941	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4942	if (error)
4943	goto out;
4944
4945	/* Nothing? See if there's anything to the right. */
4946	if (!stat) {
4947	error = xfs_btree_increment(cur, level: 0, stat: &stat);
4948	if (error)
4949	goto out;
4950	}
4951
4952	while (stat) {
4953	/* Find the record. */
4954	error = xfs_btree_get_rec(cur, recp: &recp, stat: &stat);
4955	if (error || !stat)
4956	break;
4957
4958	/* Skip if low_key > high_key(rec). */
4959	if (firstrec) {
4960	cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4961	firstrec = false;
4962	if (xfs_btree_keycmp_gt(cur, low_key, &rec_key))
4963	goto advloop;
4964	}
4965
4966	/* Stop if low_key(rec) > high_key. */
4967	cur->bc_ops->init_key_from_rec(&rec_key, recp);
4968	if (xfs_btree_keycmp_gt(cur, &rec_key, high_key))
4969	break;
4970
4971	/* Callback */
4972	error = fn(cur, recp, priv);
4973	if (error)
4974	break;
4975
4976	advloop:
4977	/* Move on to the next record. */
4978	error = xfs_btree_increment(cur, level: 0, stat: &stat);
4979	if (error)
4980	break;
4981	}
4982
4983	out:
4984	return error;
4985	}
4986
4987	/*
4988	* Query an overlapped interval btree for all records overlapping a given
4989	* interval. This function roughly follows the algorithm given in
4990	* "Interval Trees" of _Introduction to Algorithms_, which is section
4991	* 14.3 in the 2nd and 3rd editions.
4992	*
4993	* First, generate keys for the low and high records passed in.
4994	*
4995	* For any leaf node, generate the high and low keys for the record.
4996	* If the record keys overlap with the query low/high keys, pass the
4997	* record to the function iterator.
4998	*
4999	* For any internal node, compare the low and high keys of each
5000	* pointer against the query low/high keys. If there's an overlap,
5001	* follow the pointer.
5002	*
5003	* As an optimization, we stop scanning a block when we find a low key
5004	* that is greater than the query's high key.
5005	*/
5006	STATIC int
5007	xfs_btree_overlapped_query_range(
5008	struct xfs_btree_cur *cur,
5009	const union xfs_btree_key *low_key,
5010	const union xfs_btree_key *high_key,
5011	xfs_btree_query_range_fn fn,
5012	void *priv)
5013	{
5014	union xfs_btree_ptr ptr;
5015	union xfs_btree_ptr *pp;
5016	union xfs_btree_key rec_key;
5017	union xfs_btree_key rec_hkey;
5018	union xfs_btree_key *lkp;
5019	union xfs_btree_key *hkp;
5020	union xfs_btree_rec *recp;
5021	struct xfs_btree_block *block;
5022	int level;
5023	struct xfs_buf *bp;
5024	int i;
5025	int error;
5026
5027	/* Load the root of the btree. */
5028	level = cur->bc_nlevels - 1;
5029	xfs_btree_init_ptr_from_cur(cur, ptr: &ptr);
5030	error = xfs_btree_lookup_get_block(cur, level, pp: &ptr, blkp: &block);
5031	if (error)
5032	return error;
5033	xfs_btree_get_block(cur, level, bpp: &bp);
5034	trace_xfs_btree_overlapped_query_range(cur, level, bp);
5035	#ifdef DEBUG
5036	error = xfs_btree_check_block(cur, block, level, bp);
5037	if (error)
5038	goto out;
5039	#endif
5040	cur->bc_levels[level].ptr = 1;
5041
5042	while (level < cur->bc_nlevels) {
5043	block = xfs_btree_get_block(cur, level, bpp: &bp);
5044
5045	/* End of node, pop back towards the root. */
5046	if (cur->bc_levels[level].ptr >
5047	be16_to_cpu(block->bb_numrecs)) {
5048	pop_up:
5049	if (level < cur->bc_nlevels - 1)
5050	cur->bc_levels[level + 1].ptr++;
5051	level++;
5052	continue;
5053	}
5054
5055	if (level == 0) {
5056	/* Handle a leaf node. */
5057	recp = xfs_btree_rec_addr(cur, n: cur->bc_levels[0].ptr,
5058	block);
5059
5060	cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
5061	cur->bc_ops->init_key_from_rec(&rec_key, recp);
5062
5063	/*
5064	* If (query's high key < record's low key), then there
5065	* are no more interesting records in this block. Pop
5066	* up to the leaf level to find more record blocks.
5067	*
5068	* If (record's high key >= query's low key) and
5069	* (query's high key >= record's low key), then
5070	* this record overlaps the query range; callback.
5071	*/
5072	if (xfs_btree_keycmp_lt(cur, high_key, &rec_key))
5073	goto pop_up;
5074	if (xfs_btree_keycmp_ge(cur, &rec_hkey, low_key)) {
5075	error = fn(cur, recp, priv);
5076	if (error)
5077	break;
5078	}
5079	cur->bc_levels[level].ptr++;
5080	continue;
5081	}
5082
5083	/* Handle an internal node. */
5084	lkp = xfs_btree_key_addr(cur, n: cur->bc_levels[level].ptr, block);
5085	hkp = xfs_btree_high_key_addr(cur, n: cur->bc_levels[level].ptr,
5086	block);
5087	pp = xfs_btree_ptr_addr(cur, n: cur->bc_levels[level].ptr, block);
5088
5089	/*
5090	* If (query's high key < pointer's low key), then there are no
5091	* more interesting keys in this block. Pop up one leaf level
5092	* to continue looking for records.
5093	*
5094	* If (pointer's high key >= query's low key) and
5095	* (query's high key >= pointer's low key), then
5096	* this record overlaps the query range; follow pointer.
5097	*/
5098	if (xfs_btree_keycmp_lt(cur, high_key, lkp))
5099	goto pop_up;
5100	if (xfs_btree_keycmp_ge(cur, hkp, low_key)) {
5101	level--;
5102	error = xfs_btree_lookup_get_block(cur, level, pp,
5103	blkp: &block);
5104	if (error)
5105	goto out;
5106	xfs_btree_get_block(cur, level, bpp: &bp);
5107	trace_xfs_btree_overlapped_query_range(cur, level, bp);
5108	#ifdef DEBUG
5109	error = xfs_btree_check_block(cur, block, level, bp);
5110	if (error)
5111	goto out;
5112	#endif
5113	cur->bc_levels[level].ptr = 1;
5114	continue;
5115	}
5116	cur->bc_levels[level].ptr++;
5117	}
5118
5119	out:
5120	/*
5121	* If we don't end this function with the cursor pointing at a record
5122	* block, a subsequent non-error cursor deletion will not release
5123	* node-level buffers, causing a buffer leak. This is quite possible
5124	* with a zero-results range query, so release the buffers if we
5125	* failed to return any results.
5126	*/
5127	if (cur->bc_levels[0].bp == NULL) {
5128	for (i = 0; i < cur->bc_nlevels; i++) {
5129	if (cur->bc_levels[i].bp) {
5130	xfs_trans_brelse(cur->bc_tp,
5131	cur->bc_levels[i].bp);
5132	cur->bc_levels[i].bp = NULL;
5133	cur->bc_levels[i].ptr = 0;
5134	cur->bc_levels[i].ra = 0;
5135	}
5136	}
5137	}
5138
5139	return error;
5140	}
5141
5142	static inline void
5143	xfs_btree_key_from_irec(
5144	struct xfs_btree_cur *cur,
5145	union xfs_btree_key *key,
5146	const union xfs_btree_irec *irec)
5147	{
5148	union xfs_btree_rec rec;
5149
5150	cur->bc_rec = *irec;
5151	cur->bc_ops->init_rec_from_cur(cur, &rec);
5152	cur->bc_ops->init_key_from_rec(key, &rec);
5153	}
5154
5155	/*
5156	* Query a btree for all records overlapping a given interval of keys. The
5157	* supplied function will be called with each record found; return one of the
5158	* XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
5159	* code. This function returns -ECANCELED, zero, or a negative error code.
5160	*/
5161	int
5162	xfs_btree_query_range(
5163	struct xfs_btree_cur *cur,
5164	const union xfs_btree_irec *low_rec,
5165	const union xfs_btree_irec *high_rec,
5166	xfs_btree_query_range_fn fn,
5167	void *priv)
5168	{
5169	union xfs_btree_key low_key;
5170	union xfs_btree_key high_key;
5171
5172	/* Find the keys of both ends of the interval. */
5173	xfs_btree_key_from_irec(cur, key: &high_key, irec: high_rec);
5174	xfs_btree_key_from_irec(cur, key: &low_key, irec: low_rec);
5175
5176	/* Enforce low key <= high key. */
5177	if (!xfs_btree_keycmp_le(cur, &low_key, &high_key))
5178	return -EINVAL;
5179
5180	if (!(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING))
5181	return xfs_btree_simple_query_range(cur, &low_key,
5182	&high_key, fn, priv);
5183	return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
5184	fn, priv);
5185	}
5186
5187	/* Query a btree for all records. */
5188	int
5189	xfs_btree_query_all(
5190	struct xfs_btree_cur *cur,
5191	xfs_btree_query_range_fn fn,
5192	void *priv)
5193	{
5194	union xfs_btree_key low_key;
5195	union xfs_btree_key high_key;
5196
5197	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
5198	memset(&low_key, 0, sizeof(low_key));
5199	memset(&high_key, 0xFF, sizeof(high_key));
5200
5201	return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
5202	}
5203
5204	static int
5205	xfs_btree_count_blocks_helper(
5206	struct xfs_btree_cur *cur,
5207	int level,
5208	void *data)
5209	{
5210	xfs_extlen_t *blocks = data;
5211	(*blocks)++;
5212
5213	return 0;
5214	}
5215
5216	/* Count the blocks in a btree and return the result in *blocks. */
5217	int
5218	xfs_btree_count_blocks(
5219	struct xfs_btree_cur *cur,
5220	xfs_extlen_t *blocks)
5221	{
5222	*blocks = 0;
5223	return xfs_btree_visit_blocks(cur, fn: xfs_btree_count_blocks_helper,
5224	XFS_BTREE_VISIT_ALL, data: blocks);
5225	}
5226
5227	/* Compare two btree pointers. */
5228	int64_t
5229	xfs_btree_diff_two_ptrs(
5230	struct xfs_btree_cur *cur,
5231	const union xfs_btree_ptr *a,
5232	const union xfs_btree_ptr *b)
5233	{
5234	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
5235	return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
5236	return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
5237	}
5238
5239	struct xfs_btree_has_records {
5240	/* Keys for the start and end of the range we want to know about. */
5241	union xfs_btree_key start_key;
5242	union xfs_btree_key end_key;
5243
5244	/* Mask for key comparisons, if desired. */
5245	const union xfs_btree_key *key_mask;
5246
5247	/* Highest record key we've seen so far. */
5248	union xfs_btree_key high_key;
5249
5250	enum xbtree_recpacking outcome;
5251	};
5252
5253	STATIC int
5254	xfs_btree_has_records_helper(
5255	struct xfs_btree_cur *cur,
5256	const union xfs_btree_rec *rec,
5257	void *priv)
5258	{
5259	union xfs_btree_key rec_key;
5260	union xfs_btree_key rec_high_key;
5261	struct xfs_btree_has_records *info = priv;
5262	enum xbtree_key_contig key_contig;
5263
5264	cur->bc_ops->init_key_from_rec(&rec_key, rec);
5265
5266	if (info->outcome == XBTREE_RECPACKING_EMPTY) {
5267	info->outcome = XBTREE_RECPACKING_SPARSE;
5268
5269	/*
5270	* If the first record we find does not overlap the start key,
5271	* then there is a hole at the start of the search range.
5272	* Classify this as sparse and stop immediately.
5273	*/
5274	if (xfs_btree_masked_keycmp_lt(cur, &info->start_key, &rec_key,
5275	info->key_mask))
5276	return -ECANCELED;
5277	} else {
5278	/*
5279	* If a subsequent record does not overlap with the any record
5280	* we've seen so far, there is a hole in the middle of the
5281	* search range. Classify this as sparse and stop.
5282	* If the keys overlap and this btree does not allow overlap,
5283	* signal corruption.
5284	*/
5285	key_contig = cur->bc_ops->keys_contiguous(cur, &info->high_key,
5286	&rec_key, info->key_mask);
5287	if (key_contig == XBTREE_KEY_OVERLAP &&
5288	!(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING))
5289	return -EFSCORRUPTED;
5290	if (key_contig == XBTREE_KEY_GAP)
5291	return -ECANCELED;
5292	}
5293
5294	/*
5295	* If high_key(rec) is larger than any other high key we've seen,
5296	* remember it for later.
5297	*/
5298	cur->bc_ops->init_high_key_from_rec(&rec_high_key, rec);
5299	if (xfs_btree_masked_keycmp_gt(cur, &rec_high_key, &info->high_key,
5300	info->key_mask))
5301	info->high_key = rec_high_key; /* struct copy */
5302
5303	return 0;
5304	}
5305
5306	/*
5307	* Scan part of the keyspace of a btree and tell us if that keyspace does not
5308	* map to any records; is fully mapped to records; or is partially mapped to
5309	* records. This is the btree record equivalent to determining if a file is
5310	* sparse.
5311	*
5312	* For most btree types, the record scan should use all available btree key
5313	* fields to compare the keys encountered. These callers should pass NULL for
5314	* @mask. However, some callers (e.g. scanning physical space in the rmapbt)
5315	* want to ignore some part of the btree record keyspace when performing the
5316	* comparison. These callers should pass in a union xfs_btree_key object with
5317	* the fields that *should* be a part of the comparison set to any nonzero
5318	* value, and the rest zeroed.
5319	*/
5320	int
5321	xfs_btree_has_records(
5322	struct xfs_btree_cur *cur,
5323	const union xfs_btree_irec *low,
5324	const union xfs_btree_irec *high,
5325	const union xfs_btree_key *mask,
5326	enum xbtree_recpacking *outcome)
5327	{
5328	struct xfs_btree_has_records info = {
5329	.outcome = XBTREE_RECPACKING_EMPTY,
5330	.key_mask = mask,
5331	};
5332	int error;
5333
5334	/* Not all btrees support this operation. */
5335	if (!cur->bc_ops->keys_contiguous) {
5336	ASSERT(0);
5337	return -EOPNOTSUPP;
5338	}
5339
5340	xfs_btree_key_from_irec(cur, key: &info.start_key, irec: low);
5341	xfs_btree_key_from_irec(cur, key: &info.end_key, irec: high);
5342
5343	error = xfs_btree_query_range(cur, low_rec: low, high_rec: high,
5344	fn: xfs_btree_has_records_helper, priv: &info);
5345	if (error == -ECANCELED)
5346	goto out;
5347	if (error)
5348	return error;
5349
5350	if (info.outcome == XBTREE_RECPACKING_EMPTY)
5351	goto out;
5352
5353	/*
5354	* If the largest high_key(rec) we saw during the walk is greater than
5355	* the end of the search range, classify this as full. Otherwise,
5356	* there is a hole at the end of the search range.
5357	*/
5358	if (xfs_btree_masked_keycmp_ge(cur, &info.high_key, &info.end_key,
5359	mask))
5360	info.outcome = XBTREE_RECPACKING_FULL;
5361
5362	out:
5363	*outcome = info.outcome;
5364	return 0;
5365	}
5366
5367	/* Are there more records in this btree? */
5368	bool
5369	xfs_btree_has_more_records(
5370	struct xfs_btree_cur *cur)
5371	{
5372	struct xfs_btree_block *block;
5373	struct xfs_buf *bp;
5374
5375	block = xfs_btree_get_block(cur, level: 0, bpp: &bp);
5376
5377	/* There are still records in this block. */
5378	if (cur->bc_levels[0].ptr < xfs_btree_get_numrecs(block))
5379	return true;
5380
5381	/* There are more record blocks. */
5382	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
5383	return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
5384	else
5385	return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
5386	}
5387
5388	/* Set up all the btree cursor caches. */
5389	int __init
5390	xfs_btree_init_cur_caches(void)
5391	{
5392	int error;
5393
5394	error = xfs_allocbt_init_cur_cache();
5395	if (error)
5396	return error;
5397	error = xfs_inobt_init_cur_cache();
5398	if (error)
5399	goto err;
5400	error = xfs_bmbt_init_cur_cache();
5401	if (error)
5402	goto err;
5403	error = xfs_rmapbt_init_cur_cache();
5404	if (error)
5405	goto err;
5406	error = xfs_refcountbt_init_cur_cache();
5407	if (error)
5408	goto err;
5409
5410	return 0;
5411	err:
5412	xfs_btree_destroy_cur_caches();
5413	return error;
5414	}
5415
5416	/* Destroy all the btree cursor caches, if they've been allocated. */
5417	void
5418	xfs_btree_destroy_cur_caches(void)
5419	{
5420	xfs_allocbt_destroy_cur_cache();
5421	xfs_inobt_destroy_cur_cache();
5422	xfs_bmbt_destroy_cur_cache();
5423	xfs_rmapbt_destroy_cur_cache();
5424	xfs_refcountbt_destroy_cur_cache();
5425	}
5426
5427	/* Move the btree cursor before the first record. */
5428	int
5429	xfs_btree_goto_left_edge(
5430	struct xfs_btree_cur *cur)
5431	{
5432	int stat = 0;
5433	int error;
5434
5435	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
5436	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
5437	if (error)
5438	return error;
5439	if (!stat)
5440	return 0;
5441
5442	error = xfs_btree_decrement(cur, level: 0, stat: &stat);
5443	if (error)
5444	return error;
5445	if (stat != 0) {
5446	ASSERT(0);
5447	xfs_btree_mark_sick(cur);
5448	return -EFSCORRUPTED;
5449	}
5450
5451	return 0;
5452	}
5453